Commit e5b46eab3b
Changed files (7)
lib
src
lib/std/dwarf/abi.zig → lib/std/debug/Dwarf/abi.zig
@@ -1,5 +1,5 @@
const builtin = @import("builtin");
-const std = @import("../std.zig");
+const std = @import("../../std.zig");
const mem = std.mem;
const native_os = builtin.os.tag;
const posix = std.posix;
@@ -392,7 +392,7 @@ pub fn regBytes(
/// Returns the ABI-defined default value this register has in the unwinding table
/// before running any of the CIE instructions. The DWARF spec defines these as having
/// the .undefined rule by default, but allows ABI authors to override that.
-pub fn getRegDefaultValue(reg_number: u8, context: *std.dwarf.UnwindContext, out: []u8) !void {
+pub fn getRegDefaultValue(reg_number: u8, context: *std.debug.Dwarf.UnwindContext, out: []u8) !void {
switch (builtin.cpu.arch) {
.aarch64 => {
// Callee-saved registers are initialized as if they had the .same_value rule
lib/std/dwarf/call_frame.zig → lib/std/debug/Dwarf/call_frame.zig
@@ -1,14 +1,14 @@
const builtin = @import("builtin");
-const std = @import("../std.zig");
+const std = @import("../../std.zig");
const mem = std.mem;
const debug = std.debug;
const leb = std.leb;
-const dwarf = std.dwarf;
-const abi = dwarf.abi;
-const expressions = dwarf.expressions;
+const DW = std.dwarf;
+const abi = std.debug.Dwarf.abi;
const assert = std.debug.assert;
const native_endian = builtin.cpu.arch.endian();
+/// TODO merge with std.dwarf.CFA
const Opcode = enum(u8) {
advance_loc = 0x1 << 6,
offset = 0x2 << 6,
@@ -363,8 +363,8 @@ pub const VirtualMachine = struct {
/// Resolves the register rule and places the result into `out` (see dwarf.abi.regBytes)
pub fn resolveValue(
self: Column,
- context: *dwarf.UnwindContext,
- expression_context: dwarf.expressions.ExpressionContext,
+ context: *std.debug.Dwarf.UnwindContext,
+ expression_context: std.debug.Dwarf.expression.Context,
ma: *debug.StackIterator.MemoryAccessor,
out: []u8,
) !void {
@@ -483,8 +483,8 @@ pub const VirtualMachine = struct {
self: *VirtualMachine,
allocator: std.mem.Allocator,
pc: u64,
- cie: dwarf.CommonInformationEntry,
- fde: dwarf.FrameDescriptionEntry,
+ cie: std.debug.Dwarf.CommonInformationEntry,
+ fde: std.debug.Dwarf.FrameDescriptionEntry,
addr_size_bytes: u8,
endian: std.builtin.Endian,
) !Row {
@@ -502,7 +502,7 @@ pub const VirtualMachine = struct {
for (&streams, 0..) |stream, i| {
while (stream.pos < stream.buffer.len) {
- const instruction = try dwarf.call_frame.Instruction.read(stream, addr_size_bytes, endian);
+ const instruction = try std.debug.Dwarf.call_frame.Instruction.read(stream, addr_size_bytes, endian);
prev_row = try self.step(allocator, cie, i == 0, instruction);
if (pc < fde.pc_begin + self.current_row.offset) return prev_row;
}
@@ -515,8 +515,8 @@ pub const VirtualMachine = struct {
self: *VirtualMachine,
allocator: std.mem.Allocator,
pc: u64,
- cie: dwarf.CommonInformationEntry,
- fde: dwarf.FrameDescriptionEntry,
+ cie: std.debug.Dwarf.CommonInformationEntry,
+ fde: std.debug.Dwarf.FrameDescriptionEntry,
) !Row {
return self.runTo(allocator, pc, cie, fde, @sizeOf(usize), builtin.target.cpu.arch.endian());
}
@@ -538,7 +538,7 @@ pub const VirtualMachine = struct {
pub fn step(
self: *VirtualMachine,
allocator: std.mem.Allocator,
- cie: dwarf.CommonInformationEntry,
+ cie: std.debug.Dwarf.CommonInformationEntry,
is_initial: bool,
instruction: Instruction,
) !Row {
lib/std/dwarf/expressions.zig → lib/std/debug/Dwarf/expression.zig
@@ -1,9 +1,8 @@
const std = @import("std");
const builtin = @import("builtin");
-const OP = @import("OP.zig");
const leb = std.leb;
-const dwarf = std.dwarf;
-const abi = dwarf.abi;
+const OP = std.dwarf.OP;
+const abi = std.debug.Dwarf.abi;
const mem = std.mem;
const assert = std.debug.assert;
const native_endian = builtin.cpu.arch.endian();
@@ -11,46 +10,37 @@ const native_endian = builtin.cpu.arch.endian();
/// Expressions can be evaluated in different contexts, each requiring its own set of inputs.
/// Callers should specify all the fields relevant to their context. If a field is required
/// by the expression and it isn't in the context, error.IncompleteExpressionContext is returned.
-pub const ExpressionContext = struct {
+pub const Context = struct {
/// The dwarf format of the section this expression is in
- format: dwarf.Format = .@"32",
-
+ format: std.dwarf.Format = .@"32",
/// If specified, any addresses will pass through before being accessed
memory_accessor: ?*std.debug.StackIterator.MemoryAccessor = null,
-
/// The compilation unit this expression relates to, if any
- compile_unit: ?*const dwarf.CompileUnit = null,
-
+ compile_unit: ?*const std.debug.Dwarf.CompileUnit = null,
/// When evaluating a user-presented expression, this is the address of the object being evaluated
object_address: ?*const anyopaque = null,
-
/// .debug_addr section
debug_addr: ?[]const u8 = null,
-
/// Thread context
thread_context: ?*std.debug.ThreadContext = null,
reg_context: ?abi.RegisterContext = null,
-
/// Call frame address, if in a CFI context
cfa: ?usize = null,
-
/// This expression is a sub-expression from an OP.entry_value instruction
entry_value_context: bool = false,
};
-pub const ExpressionOptions = struct {
+pub const Options = struct {
/// The address size of the target architecture
addr_size: u8 = @sizeOf(usize),
-
/// Endianness of the target architecture
endian: std.builtin.Endian = builtin.target.cpu.arch.endian(),
-
/// Restrict the stack machine to a subset of opcodes used in call frame instructions
call_frame_context: bool = false,
};
// Explicitly defined to support executing sub-expressions
-pub const ExpressionError = error{
+pub const Error = error{
UnimplementedExpressionCall,
UnimplementedOpcode,
UnimplementedUserOpcode,
@@ -75,7 +65,7 @@ pub const ExpressionError = error{
/// A stack machine that can decode and run DWARF expressions.
/// Expressions can be decoded for non-native address size and endianness,
/// but can only be executed if the current target matches the configuration.
-pub fn StackMachine(comptime options: ExpressionOptions) type {
+pub fn StackMachine(comptime options: Options) type {
const addr_type = switch (options.addr_size) {
2 => u16,
4 => u32,
@@ -186,7 +176,7 @@ pub fn StackMachine(comptime options: ExpressionOptions) type {
}
}
- pub fn readOperand(stream: *std.io.FixedBufferStream([]const u8), opcode: u8, context: ExpressionContext) !?Operand {
+ pub fn readOperand(stream: *std.io.FixedBufferStream([]const u8), opcode: u8, context: Context) !?Operand {
const reader = stream.reader();
return switch (opcode) {
OP.addr => generic(try reader.readInt(addr_type, options.endian)),
@@ -297,9 +287,9 @@ pub fn StackMachine(comptime options: ExpressionOptions) type {
self: *Self,
expression: []const u8,
allocator: std.mem.Allocator,
- context: ExpressionContext,
+ context: Context,
initial_value: ?usize,
- ) ExpressionError!?Value {
+ ) Error!?Value {
if (initial_value) |i| try self.stack.append(allocator, .{ .generic = i });
var stream = std.io.fixedBufferStream(expression);
while (try self.step(&stream, allocator, context)) {}
@@ -312,8 +302,8 @@ pub fn StackMachine(comptime options: ExpressionOptions) type {
self: *Self,
stream: *std.io.FixedBufferStream([]const u8),
allocator: std.mem.Allocator,
- context: ExpressionContext,
- ) ExpressionError!bool {
+ context: Context,
+ ) Error!bool {
if (@sizeOf(usize) != @sizeOf(addr_type) or options.endian != comptime builtin.target.cpu.arch.endian())
@compileError("Execution of non-native address sizes / endianness is not supported");
@@ -792,7 +782,7 @@ pub fn StackMachine(comptime options: ExpressionOptions) type {
};
}
-pub fn Builder(comptime options: ExpressionOptions) type {
+pub fn Builder(comptime options: Options) type {
const addr_type = switch (options.addr_size) {
2 => u16,
4 => u32,
@@ -1066,7 +1056,7 @@ const testing = std.testing;
test "DWARF expressions" {
const allocator = std.testing.allocator;
- const options = ExpressionOptions{};
+ const options = Options{};
var stack_machine = StackMachine(options){};
defer stack_machine.deinit(allocator);
@@ -1079,7 +1069,7 @@ test "DWARF expressions" {
// Literals
{
- const context = ExpressionContext{};
+ const context = Context{};
for (0..32) |i| {
try b.writeLiteral(writer, @intCast(i));
}
@@ -1125,7 +1115,7 @@ test "DWARF expressions" {
try b.writeConst(writer, i28, input[9]);
try b.writeAddr(writer, input[10]);
- var mock_compile_unit: dwarf.CompileUnit = undefined;
+ var mock_compile_unit: std.debug.Dwarf.CompileUnit = undefined;
mock_compile_unit.addr_base = 1;
var mock_debug_addr = std.ArrayList(u8).init(allocator);
@@ -1135,7 +1125,7 @@ test "DWARF expressions" {
try mock_debug_addr.writer().writeInt(usize, input[11], native_endian);
try mock_debug_addr.writer().writeInt(usize, input[12], native_endian);
- const context = ExpressionContext{
+ const context = Context{
.compile_unit = &mock_compile_unit,
.debug_addr = mock_debug_addr.items,
};
@@ -1185,7 +1175,7 @@ test "DWARF expressions" {
};
var thread_context: std.debug.ThreadContext = undefined;
std.debug.relocateContext(&thread_context);
- const context = ExpressionContext{
+ const context = Context{
.thread_context = &thread_context,
.reg_context = reg_context,
};
@@ -1228,7 +1218,7 @@ test "DWARF expressions" {
// Stack operations
{
- var context = ExpressionContext{};
+ var context = Context{};
stack_machine.reset();
program.clearRetainingCapacity();
@@ -1359,7 +1349,7 @@ test "DWARF expressions" {
// Arithmetic and Logical Operations
{
- const context = ExpressionContext{};
+ const context = Context{};
stack_machine.reset();
program.clearRetainingCapacity();
@@ -1483,7 +1473,7 @@ test "DWARF expressions" {
// Control Flow Operations
{
- const context = ExpressionContext{};
+ const context = Context{};
const expected = .{
.{ OP.le, 1, 1, 0 },
.{ OP.ge, 1, 0, 1 },
@@ -1540,7 +1530,7 @@ test "DWARF expressions" {
// Type conversions
{
- const context = ExpressionContext{};
+ const context = Context{};
stack_machine.reset();
program.clearRetainingCapacity();
@@ -1588,7 +1578,7 @@ test "DWARF expressions" {
// Special operations
{
- var context = ExpressionContext{};
+ var context = Context{};
stack_machine.reset();
program.clearRetainingCapacity();
@@ -1617,7 +1607,7 @@ test "DWARF expressions" {
};
var thread_context: std.debug.ThreadContext = undefined;
std.debug.relocateContext(&thread_context);
- context = ExpressionContext{
+ context = Context{
.thread_context = &thread_context,
.reg_context = reg_context,
};
lib/std/debug/Dwarf.zig
@@ -0,0 +1,2709 @@
+//! Implements parsing, decoding, and caching of DWARF information.
+//!
+//! For unopinionated types and bits, see `std.dwarf`.
+
+const builtin = @import("builtin");
+const std = @import("../std.zig");
+const AT = DW.AT;
+const Allocator = std.mem.Allocator;
+const DW = std.dwarf;
+const EH = DW.EH;
+const FORM = DW.FORM;
+const Format = DW.Format;
+const RLE = DW.RLE;
+const StackIterator = std.debug.StackIterator;
+const UT = DW.UT;
+const assert = std.debug.assert;
+const cast = std.math.cast;
+const maxInt = std.math.maxInt;
+const native_endian = builtin.cpu.arch.endian();
+const readInt = std.mem.readInt;
+
+const Dwarf = @This();
+
+pub const expression = @import("Dwarf/expression.zig");
+pub const abi = @import("Dwarf/abi.zig");
+pub const call_frame = @import("Dwarf/call_frame.zig");
+
+endian: std.builtin.Endian,
+sections: SectionArray = null_section_array,
+is_macho: bool,
+
+// Filled later by the initializer
+abbrev_table_list: std.ArrayListUnmanaged(Abbrev.Table) = .{},
+compile_unit_list: std.ArrayListUnmanaged(CompileUnit) = .{},
+func_list: std.ArrayListUnmanaged(Func) = .{},
+
+eh_frame_hdr: ?ExceptionFrameHeader = null,
+// These lookup tables are only used if `eh_frame_hdr` is null
+cie_map: std.AutoArrayHashMapUnmanaged(u64, CommonInformationEntry) = .{},
+// Sorted by start_pc
+fde_list: std.ArrayListUnmanaged(FrameDescriptionEntry) = .{},
+
+pub const Section = struct {
+ data: []const u8,
+ // Module-relative virtual address.
+ // Only set if the section data was loaded from disk.
+ virtual_address: ?usize = null,
+ // If `data` is owned by this Dwarf.
+ owned: bool,
+
+ pub const Id = enum {
+ debug_info,
+ debug_abbrev,
+ debug_str,
+ debug_str_offsets,
+ debug_line,
+ debug_line_str,
+ debug_ranges,
+ debug_loclists,
+ debug_rnglists,
+ debug_addr,
+ debug_names,
+ debug_frame,
+ eh_frame,
+ eh_frame_hdr,
+ };
+
+ // For sections that are not memory mapped by the loader, this is an offset
+ // from `data.ptr` to where the section would have been mapped. Otherwise,
+ // `data` is directly backed by the section and the offset is zero.
+ pub fn virtualOffset(self: Section, base_address: usize) i64 {
+ return if (self.virtual_address) |va|
+ @as(i64, @intCast(base_address + va)) -
+ @as(i64, @intCast(@intFromPtr(self.data.ptr)))
+ else
+ 0;
+ }
+};
+
+pub const Abbrev = struct {
+ code: u64,
+ tag_id: u64,
+ has_children: bool,
+ attrs: []Attr,
+
+ fn deinit(abbrev: *Abbrev, allocator: Allocator) void {
+ allocator.free(abbrev.attrs);
+ abbrev.* = undefined;
+ }
+
+ const Attr = struct {
+ id: u64,
+ form_id: u64,
+ /// Only valid if form_id is .implicit_const
+ payload: i64,
+ };
+
+ const Table = struct {
+ // offset from .debug_abbrev
+ offset: u64,
+ abbrevs: []Abbrev,
+
+ fn deinit(table: *Table, allocator: Allocator) void {
+ for (table.abbrevs) |*abbrev| {
+ abbrev.deinit(allocator);
+ }
+ allocator.free(table.abbrevs);
+ table.* = undefined;
+ }
+
+ fn get(table: *const Table, abbrev_code: u64) ?*const Abbrev {
+ return for (table.abbrevs) |*abbrev| {
+ if (abbrev.code == abbrev_code) break abbrev;
+ } else null;
+ }
+ };
+};
+
+pub const CompileUnit = struct {
+ version: u16,
+ format: Format,
+ die: Die,
+ pc_range: ?PcRange,
+
+ str_offsets_base: usize,
+ addr_base: usize,
+ rnglists_base: usize,
+ loclists_base: usize,
+ frame_base: ?*const FormValue,
+};
+
+pub const FormValue = union(enum) {
+ addr: u64,
+ addrx: usize,
+ block: []const u8,
+ udata: u64,
+ data16: *const [16]u8,
+ sdata: i64,
+ exprloc: []const u8,
+ flag: bool,
+ sec_offset: u64,
+ ref: u64,
+ ref_addr: u64,
+ string: [:0]const u8,
+ strp: u64,
+ strx: usize,
+ line_strp: u64,
+ loclistx: u64,
+ rnglistx: u64,
+
+ fn getString(fv: FormValue, di: Dwarf) ![:0]const u8 {
+ switch (fv) {
+ .string => |s| return s,
+ .strp => |off| return di.getString(off),
+ .line_strp => |off| return di.getLineString(off),
+ else => return badDwarf(),
+ }
+ }
+
+ fn getUInt(fv: FormValue, comptime U: type) !U {
+ return switch (fv) {
+ inline .udata,
+ .sdata,
+ .sec_offset,
+ => |c| cast(U, c) orelse badDwarf(),
+ else => badDwarf(),
+ };
+ }
+};
+
+pub const Die = struct {
+ tag_id: u64,
+ has_children: bool,
+ attrs: []Attr,
+
+ const Attr = struct {
+ id: u64,
+ value: FormValue,
+ };
+
+ fn deinit(self: *Die, allocator: Allocator) void {
+ allocator.free(self.attrs);
+ self.* = undefined;
+ }
+
+ fn getAttr(self: *const Die, id: u64) ?*const FormValue {
+ for (self.attrs) |*attr| {
+ if (attr.id == id) return &attr.value;
+ }
+ return null;
+ }
+
+ fn getAttrAddr(
+ self: *const Die,
+ di: *const Dwarf,
+ id: u64,
+ compile_unit: CompileUnit,
+ ) error{ InvalidDebugInfo, MissingDebugInfo }!u64 {
+ const form_value = self.getAttr(id) orelse return error.MissingDebugInfo;
+ return switch (form_value.*) {
+ .addr => |value| value,
+ .addrx => |index| di.readDebugAddr(compile_unit, index),
+ else => error.InvalidDebugInfo,
+ };
+ }
+
+ fn getAttrSecOffset(self: *const Die, id: u64) !u64 {
+ const form_value = self.getAttr(id) orelse return error.MissingDebugInfo;
+ return form_value.getUInt(u64);
+ }
+
+ fn getAttrUnsignedLe(self: *const Die, id: u64) !u64 {
+ const form_value = self.getAttr(id) orelse return error.MissingDebugInfo;
+ return switch (form_value.*) {
+ .Const => |value| value.asUnsignedLe(),
+ else => error.InvalidDebugInfo,
+ };
+ }
+
+ fn getAttrRef(self: *const Die, id: u64) !u64 {
+ const form_value = self.getAttr(id) orelse return error.MissingDebugInfo;
+ return switch (form_value.*) {
+ .ref => |value| value,
+ else => error.InvalidDebugInfo,
+ };
+ }
+
+ pub fn getAttrString(
+ self: *const Die,
+ di: *Dwarf,
+ id: u64,
+ opt_str: ?[]const u8,
+ compile_unit: CompileUnit,
+ ) error{ InvalidDebugInfo, MissingDebugInfo }![]const u8 {
+ const form_value = self.getAttr(id) orelse return error.MissingDebugInfo;
+ switch (form_value.*) {
+ .string => |value| return value,
+ .strp => |offset| return di.getString(offset),
+ .strx => |index| {
+ const debug_str_offsets = di.section(.debug_str_offsets) orelse return badDwarf();
+ if (compile_unit.str_offsets_base == 0) return badDwarf();
+ switch (compile_unit.format) {
+ .@"32" => {
+ const byte_offset = compile_unit.str_offsets_base + 4 * index;
+ if (byte_offset + 4 > debug_str_offsets.len) return badDwarf();
+ const offset = readInt(u32, debug_str_offsets[byte_offset..][0..4], di.endian);
+ return getStringGeneric(opt_str, offset);
+ },
+ .@"64" => {
+ const byte_offset = compile_unit.str_offsets_base + 8 * index;
+ if (byte_offset + 8 > debug_str_offsets.len) return badDwarf();
+ const offset = readInt(u64, debug_str_offsets[byte_offset..][0..8], di.endian);
+ return getStringGeneric(opt_str, offset);
+ },
+ }
+ },
+ .line_strp => |offset| return di.getLineString(offset),
+ else => return badDwarf(),
+ }
+ }
+};
+
+/// This represents the decoded .eh_frame_hdr header
+pub const ExceptionFrameHeader = struct {
+ eh_frame_ptr: usize,
+ table_enc: u8,
+ fde_count: usize,
+ entries: []const u8,
+
+ pub fn entrySize(table_enc: u8) !u8 {
+ return switch (table_enc & EH.PE.type_mask) {
+ EH.PE.udata2,
+ EH.PE.sdata2,
+ => 4,
+ EH.PE.udata4,
+ EH.PE.sdata4,
+ => 8,
+ EH.PE.udata8,
+ EH.PE.sdata8,
+ => 16,
+ // This is a binary search table, so all entries must be the same length
+ else => return badDwarf(),
+ };
+ }
+
+ fn isValidPtr(
+ self: ExceptionFrameHeader,
+ comptime T: type,
+ ptr: usize,
+ ma: *StackIterator.MemoryAccessor,
+ eh_frame_len: ?usize,
+ ) bool {
+ if (eh_frame_len) |len| {
+ return ptr >= self.eh_frame_ptr and ptr <= self.eh_frame_ptr + len - @sizeOf(T);
+ } else {
+ return ma.load(T, ptr) != null;
+ }
+ }
+
+ /// Find an entry by binary searching the eh_frame_hdr section.
+ ///
+ /// Since the length of the eh_frame section (`eh_frame_len`) may not be known by the caller,
+ /// MemoryAccessor will be used to verify readability of the header entries.
+ /// If `eh_frame_len` is provided, then these checks can be skipped.
+ pub fn findEntry(
+ self: ExceptionFrameHeader,
+ ma: *StackIterator.MemoryAccessor,
+ eh_frame_len: ?usize,
+ eh_frame_hdr_ptr: usize,
+ pc: usize,
+ cie: *CommonInformationEntry,
+ fde: *FrameDescriptionEntry,
+ ) !void {
+ const entry_size = try entrySize(self.table_enc);
+
+ var left: usize = 0;
+ var len: usize = self.fde_count;
+
+ var fbr: FixedBufferReader = .{ .buf = self.entries, .endian = native_endian };
+
+ while (len > 1) {
+ const mid = left + len / 2;
+
+ fbr.pos = mid * entry_size;
+ const pc_begin = try readEhPointer(&fbr, self.table_enc, @sizeOf(usize), .{
+ .pc_rel_base = @intFromPtr(&self.entries[fbr.pos]),
+ .follow_indirect = true,
+ .data_rel_base = eh_frame_hdr_ptr,
+ }) orelse return badDwarf();
+
+ if (pc < pc_begin) {
+ len /= 2;
+ } else {
+ left = mid;
+ if (pc == pc_begin) break;
+ len -= len / 2;
+ }
+ }
+
+ if (len == 0) return badDwarf();
+ fbr.pos = left * entry_size;
+
+ // Read past the pc_begin field of the entry
+ _ = try readEhPointer(&fbr, self.table_enc, @sizeOf(usize), .{
+ .pc_rel_base = @intFromPtr(&self.entries[fbr.pos]),
+ .follow_indirect = true,
+ .data_rel_base = eh_frame_hdr_ptr,
+ }) orelse return badDwarf();
+
+ const fde_ptr = cast(usize, try readEhPointer(&fbr, self.table_enc, @sizeOf(usize), .{
+ .pc_rel_base = @intFromPtr(&self.entries[fbr.pos]),
+ .follow_indirect = true,
+ .data_rel_base = eh_frame_hdr_ptr,
+ }) orelse return badDwarf()) orelse return badDwarf();
+
+ if (fde_ptr < self.eh_frame_ptr) return badDwarf();
+
+ // Even if eh_frame_len is not specified, all ranges accssed are checked via MemoryAccessor
+ const eh_frame = @as([*]const u8, @ptrFromInt(self.eh_frame_ptr))[0 .. eh_frame_len orelse maxInt(u32)];
+
+ const fde_offset = fde_ptr - self.eh_frame_ptr;
+ var eh_frame_fbr: FixedBufferReader = .{
+ .buf = eh_frame,
+ .pos = fde_offset,
+ .endian = native_endian,
+ };
+
+ const fde_entry_header = try EntryHeader.read(&eh_frame_fbr, if (eh_frame_len == null) ma else null, .eh_frame);
+ if (!self.isValidPtr(u8, @intFromPtr(&fde_entry_header.entry_bytes[fde_entry_header.entry_bytes.len - 1]), ma, eh_frame_len)) return badDwarf();
+ if (fde_entry_header.type != .fde) return badDwarf();
+
+ // CIEs always come before FDEs (the offset is a subtraction), so we can assume this memory is readable
+ const cie_offset = fde_entry_header.type.fde;
+ try eh_frame_fbr.seekTo(cie_offset);
+ const cie_entry_header = try EntryHeader.read(&eh_frame_fbr, if (eh_frame_len == null) ma else null, .eh_frame);
+ if (!self.isValidPtr(u8, @intFromPtr(&cie_entry_header.entry_bytes[cie_entry_header.entry_bytes.len - 1]), ma, eh_frame_len)) return badDwarf();
+ if (cie_entry_header.type != .cie) return badDwarf();
+
+ cie.* = try CommonInformationEntry.parse(
+ cie_entry_header.entry_bytes,
+ 0,
+ true,
+ cie_entry_header.format,
+ .eh_frame,
+ cie_entry_header.length_offset,
+ @sizeOf(usize),
+ native_endian,
+ );
+
+ fde.* = try FrameDescriptionEntry.parse(
+ fde_entry_header.entry_bytes,
+ 0,
+ true,
+ cie.*,
+ @sizeOf(usize),
+ native_endian,
+ );
+ }
+};
+
+pub const EntryHeader = struct {
+ /// Offset of the length field in the backing buffer
+ length_offset: usize,
+ format: Format,
+ type: union(enum) {
+ cie,
+ /// Value is the offset of the corresponding CIE
+ fde: u64,
+ terminator,
+ },
+ /// The entry's contents, not including the ID field
+ entry_bytes: []const u8,
+
+ /// The length of the entry including the ID field, but not the length field itself
+ pub fn entryLength(self: EntryHeader) usize {
+ return self.entry_bytes.len + @as(u8, if (self.format == .@"64") 8 else 4);
+ }
+
+ /// Reads a header for either an FDE or a CIE, then advances the fbr to the position after the trailing structure.
+ /// `fbr` must be a FixedBufferReader backed by either the .eh_frame or .debug_frame sections.
+ pub fn read(
+ fbr: *FixedBufferReader,
+ opt_ma: ?*StackIterator.MemoryAccessor,
+ dwarf_section: Section.Id,
+ ) !EntryHeader {
+ assert(dwarf_section == .eh_frame or dwarf_section == .debug_frame);
+
+ const length_offset = fbr.pos;
+ const unit_header = try readUnitHeader(fbr, opt_ma);
+ const unit_length = cast(usize, unit_header.unit_length) orelse return badDwarf();
+ if (unit_length == 0) return .{
+ .length_offset = length_offset,
+ .format = unit_header.format,
+ .type = .terminator,
+ .entry_bytes = &.{},
+ };
+ const start_offset = fbr.pos;
+ const end_offset = start_offset + unit_length;
+ defer fbr.pos = end_offset;
+
+ const id = try if (opt_ma) |ma|
+ fbr.readAddressChecked(unit_header.format, ma)
+ else
+ fbr.readAddress(unit_header.format);
+ const entry_bytes = fbr.buf[fbr.pos..end_offset];
+ const cie_id: u64 = switch (dwarf_section) {
+ .eh_frame => CommonInformationEntry.eh_id,
+ .debug_frame => switch (unit_header.format) {
+ .@"32" => CommonInformationEntry.dwarf32_id,
+ .@"64" => CommonInformationEntry.dwarf64_id,
+ },
+ else => unreachable,
+ };
+
+ return .{
+ .length_offset = length_offset,
+ .format = unit_header.format,
+ .type = if (id == cie_id) .cie else .{ .fde = switch (dwarf_section) {
+ .eh_frame => try std.math.sub(u64, start_offset, id),
+ .debug_frame => id,
+ else => unreachable,
+ } },
+ .entry_bytes = entry_bytes,
+ };
+ }
+};
+
+pub const CommonInformationEntry = struct {
+ // Used in .eh_frame
+ pub const eh_id = 0;
+
+ // Used in .debug_frame (DWARF32)
+ pub const dwarf32_id = maxInt(u32);
+
+ // Used in .debug_frame (DWARF64)
+ pub const dwarf64_id = maxInt(u64);
+
+ // Offset of the length field of this entry in the eh_frame section.
+ // This is the key that FDEs use to reference CIEs.
+ length_offset: u64,
+ version: u8,
+ address_size: u8,
+ format: Format,
+
+ // Only present in version 4
+ segment_selector_size: ?u8,
+
+ code_alignment_factor: u32,
+ data_alignment_factor: i32,
+ return_address_register: u8,
+
+ aug_str: []const u8,
+ aug_data: []const u8,
+ lsda_pointer_enc: u8,
+ personality_enc: ?u8,
+ personality_routine_pointer: ?u64,
+ fde_pointer_enc: u8,
+ initial_instructions: []const u8,
+
+ pub fn isSignalFrame(self: CommonInformationEntry) bool {
+ for (self.aug_str) |c| if (c == 'S') return true;
+ return false;
+ }
+
+ pub fn addressesSignedWithBKey(self: CommonInformationEntry) bool {
+ for (self.aug_str) |c| if (c == 'B') return true;
+ return false;
+ }
+
+ pub fn mteTaggedFrame(self: CommonInformationEntry) bool {
+ for (self.aug_str) |c| if (c == 'G') return true;
+ return false;
+ }
+
+ /// This function expects to read the CIE starting with the version field.
+ /// The returned struct references memory backed by cie_bytes.
+ ///
+ /// See the FrameDescriptionEntry.parse documentation for the description
+ /// of `pc_rel_offset` and `is_runtime`.
+ ///
+ /// `length_offset` specifies the offset of this CIE's length field in the
+ /// .eh_frame / .debug_frame section.
+ pub fn parse(
+ cie_bytes: []const u8,
+ pc_rel_offset: i64,
+ is_runtime: bool,
+ format: Format,
+ dwarf_section: Section.Id,
+ length_offset: u64,
+ addr_size_bytes: u8,
+ endian: std.builtin.Endian,
+ ) !CommonInformationEntry {
+ if (addr_size_bytes > 8) return error.UnsupportedAddrSize;
+
+ var fbr: FixedBufferReader = .{ .buf = cie_bytes, .endian = endian };
+
+ const version = try fbr.readByte();
+ switch (dwarf_section) {
+ .eh_frame => if (version != 1 and version != 3) return error.UnsupportedDwarfVersion,
+ .debug_frame => if (version != 4) return error.UnsupportedDwarfVersion,
+ else => return error.UnsupportedDwarfSection,
+ }
+
+ var has_eh_data = false;
+ var has_aug_data = false;
+
+ var aug_str_len: usize = 0;
+ const aug_str_start = fbr.pos;
+ var aug_byte = try fbr.readByte();
+ while (aug_byte != 0) : (aug_byte = try fbr.readByte()) {
+ switch (aug_byte) {
+ 'z' => {
+ if (aug_str_len != 0) return badDwarf();
+ has_aug_data = true;
+ },
+ 'e' => {
+ if (has_aug_data or aug_str_len != 0) return badDwarf();
+ if (try fbr.readByte() != 'h') return badDwarf();
+ has_eh_data = true;
+ },
+ else => if (has_eh_data) return badDwarf(),
+ }
+
+ aug_str_len += 1;
+ }
+
+ if (has_eh_data) {
+ // legacy data created by older versions of gcc - unsupported here
+ for (0..addr_size_bytes) |_| _ = try fbr.readByte();
+ }
+
+ const address_size = if (version == 4) try fbr.readByte() else addr_size_bytes;
+ const segment_selector_size = if (version == 4) try fbr.readByte() else null;
+
+ const code_alignment_factor = try fbr.readUleb128(u32);
+ const data_alignment_factor = try fbr.readIleb128(i32);
+ const return_address_register = if (version == 1) try fbr.readByte() else try fbr.readUleb128(u8);
+
+ var lsda_pointer_enc: u8 = EH.PE.omit;
+ var personality_enc: ?u8 = null;
+ var personality_routine_pointer: ?u64 = null;
+ var fde_pointer_enc: u8 = EH.PE.absptr;
+
+ var aug_data: []const u8 = &[_]u8{};
+ const aug_str = if (has_aug_data) blk: {
+ const aug_data_len = try fbr.readUleb128(usize);
+ const aug_data_start = fbr.pos;
+ aug_data = cie_bytes[aug_data_start..][0..aug_data_len];
+
+ const aug_str = cie_bytes[aug_str_start..][0..aug_str_len];
+ for (aug_str[1..]) |byte| {
+ switch (byte) {
+ 'L' => {
+ lsda_pointer_enc = try fbr.readByte();
+ },
+ 'P' => {
+ personality_enc = try fbr.readByte();
+ personality_routine_pointer = try readEhPointer(&fbr, personality_enc.?, addr_size_bytes, .{
+ .pc_rel_base = try pcRelBase(@intFromPtr(&cie_bytes[fbr.pos]), pc_rel_offset),
+ .follow_indirect = is_runtime,
+ });
+ },
+ 'R' => {
+ fde_pointer_enc = try fbr.readByte();
+ },
+ 'S', 'B', 'G' => {},
+ else => return badDwarf(),
+ }
+ }
+
+ // aug_data_len can include padding so the CIE ends on an address boundary
+ fbr.pos = aug_data_start + aug_data_len;
+ break :blk aug_str;
+ } else &[_]u8{};
+
+ const initial_instructions = cie_bytes[fbr.pos..];
+ return .{
+ .length_offset = length_offset,
+ .version = version,
+ .address_size = address_size,
+ .format = format,
+ .segment_selector_size = segment_selector_size,
+ .code_alignment_factor = code_alignment_factor,
+ .data_alignment_factor = data_alignment_factor,
+ .return_address_register = return_address_register,
+ .aug_str = aug_str,
+ .aug_data = aug_data,
+ .lsda_pointer_enc = lsda_pointer_enc,
+ .personality_enc = personality_enc,
+ .personality_routine_pointer = personality_routine_pointer,
+ .fde_pointer_enc = fde_pointer_enc,
+ .initial_instructions = initial_instructions,
+ };
+ }
+};
+
+pub const FrameDescriptionEntry = struct {
+ // Offset into eh_frame where the CIE for this FDE is stored
+ cie_length_offset: u64,
+
+ pc_begin: u64,
+ pc_range: u64,
+ lsda_pointer: ?u64,
+ aug_data: []const u8,
+ instructions: []const u8,
+
+ /// This function expects to read the FDE starting at the PC Begin field.
+ /// The returned struct references memory backed by `fde_bytes`.
+ ///
+ /// `pc_rel_offset` specifies an offset to be applied to pc_rel_base values
+ /// used when decoding pointers. This should be set to zero if fde_bytes is
+ /// backed by the memory of a .eh_frame / .debug_frame section in the running executable.
+ /// Otherwise, it should be the relative offset to translate addresses from
+ /// where the section is currently stored in memory, to where it *would* be
+ /// stored at runtime: section base addr - backing data base ptr.
+ ///
+ /// Similarly, `is_runtime` specifies this function is being called on a runtime
+ /// section, and so indirect pointers can be followed.
+ pub fn parse(
+ fde_bytes: []const u8,
+ pc_rel_offset: i64,
+ is_runtime: bool,
+ cie: CommonInformationEntry,
+ addr_size_bytes: u8,
+ endian: std.builtin.Endian,
+ ) !FrameDescriptionEntry {
+ if (addr_size_bytes > 8) return error.InvalidAddrSize;
+
+ var fbr: FixedBufferReader = .{ .buf = fde_bytes, .endian = endian };
+
+ const pc_begin = try readEhPointer(&fbr, cie.fde_pointer_enc, addr_size_bytes, .{
+ .pc_rel_base = try pcRelBase(@intFromPtr(&fde_bytes[fbr.pos]), pc_rel_offset),
+ .follow_indirect = is_runtime,
+ }) orelse return badDwarf();
+
+ const pc_range = try readEhPointer(&fbr, cie.fde_pointer_enc, addr_size_bytes, .{
+ .pc_rel_base = 0,
+ .follow_indirect = false,
+ }) orelse return badDwarf();
+
+ var aug_data: []const u8 = &[_]u8{};
+ const lsda_pointer = if (cie.aug_str.len > 0) blk: {
+ const aug_data_len = try fbr.readUleb128(usize);
+ const aug_data_start = fbr.pos;
+ aug_data = fde_bytes[aug_data_start..][0..aug_data_len];
+
+ const lsda_pointer = if (cie.lsda_pointer_enc != EH.PE.omit)
+ try readEhPointer(&fbr, cie.lsda_pointer_enc, addr_size_bytes, .{
+ .pc_rel_base = try pcRelBase(@intFromPtr(&fde_bytes[fbr.pos]), pc_rel_offset),
+ .follow_indirect = is_runtime,
+ })
+ else
+ null;
+
+ fbr.pos = aug_data_start + aug_data_len;
+ break :blk lsda_pointer;
+ } else null;
+
+ const instructions = fde_bytes[fbr.pos..];
+ return .{
+ .cie_length_offset = cie.length_offset,
+ .pc_begin = pc_begin,
+ .pc_range = pc_range,
+ .lsda_pointer = lsda_pointer,
+ .aug_data = aug_data,
+ .instructions = instructions,
+ };
+ }
+};
+
+pub const UnwindContext = struct {
+ allocator: Allocator,
+ cfa: ?usize,
+ pc: usize,
+ thread_context: *std.debug.ThreadContext,
+ reg_context: abi.RegisterContext,
+ vm: call_frame.VirtualMachine,
+ stack_machine: expression.StackMachine(.{ .call_frame_context = true }),
+
+ pub fn init(
+ allocator: Allocator,
+ thread_context: *const std.debug.ThreadContext,
+ ) !UnwindContext {
+ const pc = abi.stripInstructionPtrAuthCode(
+ (try abi.regValueNative(
+ usize,
+ thread_context,
+ abi.ipRegNum(),
+ null,
+ )).*,
+ );
+
+ const context_copy = try allocator.create(std.debug.ThreadContext);
+ std.debug.copyContext(thread_context, context_copy);
+
+ return .{
+ .allocator = allocator,
+ .cfa = null,
+ .pc = pc,
+ .thread_context = context_copy,
+ .reg_context = undefined,
+ .vm = .{},
+ .stack_machine = .{},
+ };
+ }
+
+ pub fn deinit(self: *UnwindContext) void {
+ self.vm.deinit(self.allocator);
+ self.stack_machine.deinit(self.allocator);
+ self.allocator.destroy(self.thread_context);
+ self.* = undefined;
+ }
+
+ pub fn getFp(self: *const UnwindContext) !usize {
+ return (try abi.regValueNative(usize, self.thread_context, abi.fpRegNum(self.reg_context), self.reg_context)).*;
+ }
+};
+
+const num_sections = std.enums.directEnumArrayLen(Section.Id, 0);
+pub const SectionArray = [num_sections]?Section;
+pub const null_section_array = [_]?Section{null} ** num_sections;
+
+/// Initialize DWARF info. The caller has the responsibility to initialize most
+/// the `Dwarf` fields before calling. `binary_mem` is the raw bytes of the
+/// main binary file (not the secondary debug info file).
+pub fn open(di: *Dwarf, allocator: Allocator) !void {
+ try di.scanAllFunctions(allocator);
+ try di.scanAllCompileUnits(allocator);
+}
+
+const PcRange = struct {
+ start: u64,
+ end: u64,
+};
+
+const Func = struct {
+ pc_range: ?PcRange,
+ name: ?[]const u8,
+};
+
+pub fn section(di: Dwarf, dwarf_section: Section.Id) ?[]const u8 {
+ return if (di.sections[@intFromEnum(dwarf_section)]) |s| s.data else null;
+}
+
+pub fn sectionVirtualOffset(di: Dwarf, dwarf_section: Section.Id, base_address: usize) ?i64 {
+ return if (di.sections[@intFromEnum(dwarf_section)]) |s| s.virtualOffset(base_address) else null;
+}
+
+pub fn deinit(di: *Dwarf, allocator: Allocator) void {
+ for (di.sections) |opt_section| {
+ if (opt_section) |s| if (s.owned) allocator.free(s.data);
+ }
+ for (di.abbrev_table_list.items) |*abbrev| {
+ abbrev.deinit(allocator);
+ }
+ di.abbrev_table_list.deinit(allocator);
+ for (di.compile_unit_list.items) |*cu| {
+ cu.die.deinit(allocator);
+ }
+ di.compile_unit_list.deinit(allocator);
+ di.func_list.deinit(allocator);
+ di.cie_map.deinit(allocator);
+ di.fde_list.deinit(allocator);
+ di.* = undefined;
+}
+
+pub fn getSymbolName(di: *Dwarf, address: u64) ?[]const u8 {
+ for (di.func_list.items) |*func| {
+ if (func.pc_range) |range| {
+ if (address >= range.start and address < range.end) {
+ return func.name;
+ }
+ }
+ }
+
+ return null;
+}
+
+fn scanAllFunctions(di: *Dwarf, allocator: Allocator) !void {
+ var fbr: FixedBufferReader = .{ .buf = di.section(.debug_info).?, .endian = di.endian };
+ var this_unit_offset: u64 = 0;
+
+ while (this_unit_offset < fbr.buf.len) {
+ try fbr.seekTo(this_unit_offset);
+
+ const unit_header = try readUnitHeader(&fbr, null);
+ if (unit_header.unit_length == 0) return;
+ const next_offset = unit_header.header_length + unit_header.unit_length;
+
+ const version = try fbr.readInt(u16);
+ if (version < 2 or version > 5) return badDwarf();
+
+ var address_size: u8 = undefined;
+ var debug_abbrev_offset: u64 = undefined;
+ if (version >= 5) {
+ const unit_type = try fbr.readInt(u8);
+ if (unit_type != DW.UT.compile) return badDwarf();
+ address_size = try fbr.readByte();
+ debug_abbrev_offset = try fbr.readAddress(unit_header.format);
+ } else {
+ debug_abbrev_offset = try fbr.readAddress(unit_header.format);
+ address_size = try fbr.readByte();
+ }
+ if (address_size != @sizeOf(usize)) return badDwarf();
+
+ const abbrev_table = try di.getAbbrevTable(allocator, debug_abbrev_offset);
+
+ var max_attrs: usize = 0;
+ var zig_padding_abbrev_code: u7 = 0;
+ for (abbrev_table.abbrevs) |abbrev| {
+ max_attrs = @max(max_attrs, abbrev.attrs.len);
+ if (cast(u7, abbrev.code)) |code| {
+ if (abbrev.tag_id == DW.TAG.ZIG_padding and
+ !abbrev.has_children and
+ abbrev.attrs.len == 0)
+ {
+ zig_padding_abbrev_code = code;
+ }
+ }
+ }
+ const attrs_buf = try allocator.alloc(Die.Attr, max_attrs * 3);
+ defer allocator.free(attrs_buf);
+ var attrs_bufs: [3][]Die.Attr = undefined;
+ for (&attrs_bufs, 0..) |*buf, index| buf.* = attrs_buf[index * max_attrs ..][0..max_attrs];
+
+ const next_unit_pos = this_unit_offset + next_offset;
+
+ var compile_unit: CompileUnit = .{
+ .version = version,
+ .format = unit_header.format,
+ .die = undefined,
+ .pc_range = null,
+
+ .str_offsets_base = 0,
+ .addr_base = 0,
+ .rnglists_base = 0,
+ .loclists_base = 0,
+ .frame_base = null,
+ };
+
+ while (true) {
+ fbr.pos = std.mem.indexOfNonePos(u8, fbr.buf, fbr.pos, &.{
+ zig_padding_abbrev_code, 0,
+ }) orelse fbr.buf.len;
+ if (fbr.pos >= next_unit_pos) break;
+ var die_obj = (try parseDie(
+ &fbr,
+ attrs_bufs[0],
+ abbrev_table,
+ unit_header.format,
+ )) orelse continue;
+
+ switch (die_obj.tag_id) {
+ DW.TAG.compile_unit => {
+ compile_unit.die = die_obj;
+ compile_unit.die.attrs = attrs_bufs[1][0..die_obj.attrs.len];
+ @memcpy(compile_unit.die.attrs, die_obj.attrs);
+
+ compile_unit.str_offsets_base = if (die_obj.getAttr(AT.str_offsets_base)) |fv| try fv.getUInt(usize) else 0;
+ compile_unit.addr_base = if (die_obj.getAttr(AT.addr_base)) |fv| try fv.getUInt(usize) else 0;
+ compile_unit.rnglists_base = if (die_obj.getAttr(AT.rnglists_base)) |fv| try fv.getUInt(usize) else 0;
+ compile_unit.loclists_base = if (die_obj.getAttr(AT.loclists_base)) |fv| try fv.getUInt(usize) else 0;
+ compile_unit.frame_base = die_obj.getAttr(AT.frame_base);
+ },
+ DW.TAG.subprogram, DW.TAG.inlined_subroutine, DW.TAG.subroutine, DW.TAG.entry_point => {
+ const fn_name = x: {
+ var this_die_obj = die_obj;
+ // Prevent endless loops
+ for (0..3) |_| {
+ if (this_die_obj.getAttr(AT.name)) |_| {
+ break :x try this_die_obj.getAttrString(di, AT.name, di.section(.debug_str), compile_unit);
+ } else if (this_die_obj.getAttr(AT.abstract_origin)) |_| {
+ const after_die_offset = fbr.pos;
+ defer fbr.pos = after_die_offset;
+
+ // Follow the DIE it points to and repeat
+ const ref_offset = try this_die_obj.getAttrRef(AT.abstract_origin);
+ if (ref_offset > next_offset) return badDwarf();
+ try fbr.seekTo(this_unit_offset + ref_offset);
+ this_die_obj = (try parseDie(
+ &fbr,
+ attrs_bufs[2],
+ abbrev_table,
+ unit_header.format,
+ )) orelse return badDwarf();
+ } else if (this_die_obj.getAttr(AT.specification)) |_| {
+ const after_die_offset = fbr.pos;
+ defer fbr.pos = after_die_offset;
+
+ // Follow the DIE it points to and repeat
+ const ref_offset = try this_die_obj.getAttrRef(AT.specification);
+ if (ref_offset > next_offset) return badDwarf();
+ try fbr.seekTo(this_unit_offset + ref_offset);
+ this_die_obj = (try parseDie(
+ &fbr,
+ attrs_bufs[2],
+ abbrev_table,
+ unit_header.format,
+ )) orelse return badDwarf();
+ } else {
+ break :x null;
+ }
+ }
+
+ break :x null;
+ };
+
+ var range_added = if (die_obj.getAttrAddr(di, AT.low_pc, compile_unit)) |low_pc| blk: {
+ if (die_obj.getAttr(AT.high_pc)) |high_pc_value| {
+ const pc_end = switch (high_pc_value.*) {
+ .addr => |value| value,
+ .udata => |offset| low_pc + offset,
+ else => return badDwarf(),
+ };
+
+ try di.func_list.append(allocator, .{
+ .name = fn_name,
+ .pc_range = .{
+ .start = low_pc,
+ .end = pc_end,
+ },
+ });
+
+ break :blk true;
+ }
+
+ break :blk false;
+ } else |err| blk: {
+ if (err != error.MissingDebugInfo) return err;
+ break :blk false;
+ };
+
+ if (die_obj.getAttr(AT.ranges)) |ranges_value| blk: {
+ var iter = DebugRangeIterator.init(ranges_value, di, &compile_unit) catch |err| {
+ if (err != error.MissingDebugInfo) return err;
+ break :blk;
+ };
+
+ while (try iter.next()) |range| {
+ range_added = true;
+ try di.func_list.append(allocator, .{
+ .name = fn_name,
+ .pc_range = .{
+ .start = range.start_addr,
+ .end = range.end_addr,
+ },
+ });
+ }
+ }
+
+ if (fn_name != null and !range_added) {
+ try di.func_list.append(allocator, .{
+ .name = fn_name,
+ .pc_range = null,
+ });
+ }
+ },
+ else => {},
+ }
+ }
+
+ this_unit_offset += next_offset;
+ }
+}
+
+fn scanAllCompileUnits(di: *Dwarf, allocator: Allocator) !void {
+ var fbr: FixedBufferReader = .{ .buf = di.section(.debug_info).?, .endian = di.endian };
+ var this_unit_offset: u64 = 0;
+
+ var attrs_buf = std.ArrayList(Die.Attr).init(allocator);
+ defer attrs_buf.deinit();
+
+ while (this_unit_offset < fbr.buf.len) {
+ try fbr.seekTo(this_unit_offset);
+
+ const unit_header = try readUnitHeader(&fbr, null);
+ if (unit_header.unit_length == 0) return;
+ const next_offset = unit_header.header_length + unit_header.unit_length;
+
+ const version = try fbr.readInt(u16);
+ if (version < 2 or version > 5) return badDwarf();
+
+ var address_size: u8 = undefined;
+ var debug_abbrev_offset: u64 = undefined;
+ if (version >= 5) {
+ const unit_type = try fbr.readInt(u8);
+ if (unit_type != UT.compile) return badDwarf();
+ address_size = try fbr.readByte();
+ debug_abbrev_offset = try fbr.readAddress(unit_header.format);
+ } else {
+ debug_abbrev_offset = try fbr.readAddress(unit_header.format);
+ address_size = try fbr.readByte();
+ }
+ if (address_size != @sizeOf(usize)) return badDwarf();
+
+ const abbrev_table = try di.getAbbrevTable(allocator, debug_abbrev_offset);
+
+ var max_attrs: usize = 0;
+ for (abbrev_table.abbrevs) |abbrev| {
+ max_attrs = @max(max_attrs, abbrev.attrs.len);
+ }
+ try attrs_buf.resize(max_attrs);
+
+ var compile_unit_die = (try parseDie(
+ &fbr,
+ attrs_buf.items,
+ abbrev_table,
+ unit_header.format,
+ )) orelse return badDwarf();
+
+ if (compile_unit_die.tag_id != DW.TAG.compile_unit) return badDwarf();
+
+ compile_unit_die.attrs = try allocator.dupe(Die.Attr, compile_unit_die.attrs);
+
+ var compile_unit: CompileUnit = .{
+ .version = version,
+ .format = unit_header.format,
+ .pc_range = null,
+ .die = compile_unit_die,
+ .str_offsets_base = if (compile_unit_die.getAttr(AT.str_offsets_base)) |fv| try fv.getUInt(usize) else 0,
+ .addr_base = if (compile_unit_die.getAttr(AT.addr_base)) |fv| try fv.getUInt(usize) else 0,
+ .rnglists_base = if (compile_unit_die.getAttr(AT.rnglists_base)) |fv| try fv.getUInt(usize) else 0,
+ .loclists_base = if (compile_unit_die.getAttr(AT.loclists_base)) |fv| try fv.getUInt(usize) else 0,
+ .frame_base = compile_unit_die.getAttr(AT.frame_base),
+ };
+
+ compile_unit.pc_range = x: {
+ if (compile_unit_die.getAttrAddr(di, AT.low_pc, compile_unit)) |low_pc| {
+ if (compile_unit_die.getAttr(AT.high_pc)) |high_pc_value| {
+ const pc_end = switch (high_pc_value.*) {
+ .addr => |value| value,
+ .udata => |offset| low_pc + offset,
+ else => return badDwarf(),
+ };
+ break :x PcRange{
+ .start = low_pc,
+ .end = pc_end,
+ };
+ } else {
+ break :x null;
+ }
+ } else |err| {
+ if (err != error.MissingDebugInfo) return err;
+ break :x null;
+ }
+ };
+
+ try di.compile_unit_list.append(allocator, compile_unit);
+
+ this_unit_offset += next_offset;
+ }
+}
+
+const DebugRangeIterator = struct {
+ base_address: u64,
+ section_type: Section.Id,
+ di: *const Dwarf,
+ compile_unit: *const CompileUnit,
+ fbr: FixedBufferReader,
+
+ pub fn init(ranges_value: *const FormValue, di: *const Dwarf, compile_unit: *const CompileUnit) !@This() {
+ const section_type = if (compile_unit.version >= 5) Section.Id.debug_rnglists else Section.Id.debug_ranges;
+ const debug_ranges = di.section(section_type) orelse return error.MissingDebugInfo;
+
+ const ranges_offset = switch (ranges_value.*) {
+ .sec_offset, .udata => |off| off,
+ .rnglistx => |idx| off: {
+ switch (compile_unit.format) {
+ .@"32" => {
+ const offset_loc = @as(usize, @intCast(compile_unit.rnglists_base + 4 * idx));
+ if (offset_loc + 4 > debug_ranges.len) return badDwarf();
+ const offset = readInt(u32, debug_ranges[offset_loc..][0..4], di.endian);
+ break :off compile_unit.rnglists_base + offset;
+ },
+ .@"64" => {
+ const offset_loc = @as(usize, @intCast(compile_unit.rnglists_base + 8 * idx));
+ if (offset_loc + 8 > debug_ranges.len) return badDwarf();
+ const offset = readInt(u64, debug_ranges[offset_loc..][0..8], di.endian);
+ break :off compile_unit.rnglists_base + offset;
+ },
+ }
+ },
+ else => return badDwarf(),
+ };
+
+ // All the addresses in the list are relative to the value
+ // specified by DW_AT.low_pc or to some other value encoded
+ // in the list itself.
+ // If no starting value is specified use zero.
+ const base_address = compile_unit.die.getAttrAddr(di, AT.low_pc, compile_unit.*) catch |err| switch (err) {
+ error.MissingDebugInfo => 0,
+ else => return err,
+ };
+
+ return .{
+ .base_address = base_address,
+ .section_type = section_type,
+ .di = di,
+ .compile_unit = compile_unit,
+ .fbr = .{
+ .buf = debug_ranges,
+ .pos = cast(usize, ranges_offset) orelse return badDwarf(),
+ .endian = di.endian,
+ },
+ };
+ }
+
+ // Returns the next range in the list, or null if the end was reached.
+ pub fn next(self: *@This()) !?struct { start_addr: u64, end_addr: u64 } {
+ switch (self.section_type) {
+ .debug_rnglists => {
+ const kind = try self.fbr.readByte();
+ switch (kind) {
+ RLE.end_of_list => return null,
+ RLE.base_addressx => {
+ const index = try self.fbr.readUleb128(usize);
+ self.base_address = try self.di.readDebugAddr(self.compile_unit.*, index);
+ return try self.next();
+ },
+ RLE.startx_endx => {
+ const start_index = try self.fbr.readUleb128(usize);
+ const start_addr = try self.di.readDebugAddr(self.compile_unit.*, start_index);
+
+ const end_index = try self.fbr.readUleb128(usize);
+ const end_addr = try self.di.readDebugAddr(self.compile_unit.*, end_index);
+
+ return .{
+ .start_addr = start_addr,
+ .end_addr = end_addr,
+ };
+ },
+ RLE.startx_length => {
+ const start_index = try self.fbr.readUleb128(usize);
+ const start_addr = try self.di.readDebugAddr(self.compile_unit.*, start_index);
+
+ const len = try self.fbr.readUleb128(usize);
+ const end_addr = start_addr + len;
+
+ return .{
+ .start_addr = start_addr,
+ .end_addr = end_addr,
+ };
+ },
+ RLE.offset_pair => {
+ const start_addr = try self.fbr.readUleb128(usize);
+ const end_addr = try self.fbr.readUleb128(usize);
+
+ // This is the only kind that uses the base address
+ return .{
+ .start_addr = self.base_address + start_addr,
+ .end_addr = self.base_address + end_addr,
+ };
+ },
+ RLE.base_address => {
+ self.base_address = try self.fbr.readInt(usize);
+ return try self.next();
+ },
+ RLE.start_end => {
+ const start_addr = try self.fbr.readInt(usize);
+ const end_addr = try self.fbr.readInt(usize);
+
+ return .{
+ .start_addr = start_addr,
+ .end_addr = end_addr,
+ };
+ },
+ RLE.start_length => {
+ const start_addr = try self.fbr.readInt(usize);
+ const len = try self.fbr.readUleb128(usize);
+ const end_addr = start_addr + len;
+
+ return .{
+ .start_addr = start_addr,
+ .end_addr = end_addr,
+ };
+ },
+ else => return badDwarf(),
+ }
+ },
+ .debug_ranges => {
+ const start_addr = try self.fbr.readInt(usize);
+ const end_addr = try self.fbr.readInt(usize);
+ if (start_addr == 0 and end_addr == 0) return null;
+
+ // This entry selects a new value for the base address
+ if (start_addr == maxInt(usize)) {
+ self.base_address = end_addr;
+ return try self.next();
+ }
+
+ return .{
+ .start_addr = self.base_address + start_addr,
+ .end_addr = self.base_address + end_addr,
+ };
+ },
+ else => unreachable,
+ }
+ }
+};
+
+pub fn findCompileUnit(di: *const Dwarf, target_address: u64) !*const CompileUnit {
+ for (di.compile_unit_list.items) |*compile_unit| {
+ if (compile_unit.pc_range) |range| {
+ if (target_address >= range.start and target_address < range.end) return compile_unit;
+ }
+
+ const ranges_value = compile_unit.die.getAttr(AT.ranges) orelse continue;
+ var iter = DebugRangeIterator.init(ranges_value, di, compile_unit) catch continue;
+ while (try iter.next()) |range| {
+ if (target_address >= range.start_addr and target_address < range.end_addr) return compile_unit;
+ }
+ }
+
+ return missingDwarf();
+}
+
+/// Gets an already existing AbbrevTable given the abbrev_offset, or if not found,
+/// seeks in the stream and parses it.
+fn getAbbrevTable(di: *Dwarf, allocator: Allocator, abbrev_offset: u64) !*const Abbrev.Table {
+ for (di.abbrev_table_list.items) |*table| {
+ if (table.offset == abbrev_offset) {
+ return table;
+ }
+ }
+ try di.abbrev_table_list.append(
+ allocator,
+ try di.parseAbbrevTable(allocator, abbrev_offset),
+ );
+ return &di.abbrev_table_list.items[di.abbrev_table_list.items.len - 1];
+}
+
+fn parseAbbrevTable(di: *Dwarf, allocator: Allocator, offset: u64) !Abbrev.Table {
+ var fbr: FixedBufferReader = .{
+ .buf = di.section(.debug_abbrev).?,
+ .pos = cast(usize, offset) orelse return badDwarf(),
+ .endian = di.endian,
+ };
+
+ var abbrevs = std.ArrayList(Abbrev).init(allocator);
+ defer {
+ for (abbrevs.items) |*abbrev| {
+ abbrev.deinit(allocator);
+ }
+ abbrevs.deinit();
+ }
+
+ var attrs = std.ArrayList(Abbrev.Attr).init(allocator);
+ defer attrs.deinit();
+
+ while (true) {
+ const code = try fbr.readUleb128(u64);
+ if (code == 0) break;
+ const tag_id = try fbr.readUleb128(u64);
+ const has_children = (try fbr.readByte()) == DW.CHILDREN.yes;
+
+ while (true) {
+ const attr_id = try fbr.readUleb128(u64);
+ const form_id = try fbr.readUleb128(u64);
+ if (attr_id == 0 and form_id == 0) break;
+ try attrs.append(.{
+ .id = attr_id,
+ .form_id = form_id,
+ .payload = switch (form_id) {
+ FORM.implicit_const => try fbr.readIleb128(i64),
+ else => undefined,
+ },
+ });
+ }
+
+ try abbrevs.append(.{
+ .code = code,
+ .tag_id = tag_id,
+ .has_children = has_children,
+ .attrs = try attrs.toOwnedSlice(),
+ });
+ }
+
+ return .{
+ .offset = offset,
+ .abbrevs = try abbrevs.toOwnedSlice(),
+ };
+}
+
+fn parseDie(
+ fbr: *FixedBufferReader,
+ attrs_buf: []Die.Attr,
+ abbrev_table: *const Abbrev.Table,
+ format: Format,
+) !?Die {
+ const abbrev_code = try fbr.readUleb128(u64);
+ if (abbrev_code == 0) return null;
+ const table_entry = abbrev_table.get(abbrev_code) orelse return badDwarf();
+
+ const attrs = attrs_buf[0..table_entry.attrs.len];
+ for (attrs, table_entry.attrs) |*result_attr, attr| result_attr.* = Die.Attr{
+ .id = attr.id,
+ .value = try parseFormValue(
+ fbr,
+ attr.form_id,
+ format,
+ attr.payload,
+ ),
+ };
+ return .{
+ .tag_id = table_entry.tag_id,
+ .has_children = table_entry.has_children,
+ .attrs = attrs,
+ };
+}
+
+pub fn getLineNumberInfo(
+ di: *Dwarf,
+ allocator: Allocator,
+ compile_unit: CompileUnit,
+ target_address: u64,
+) !std.debug.LineInfo {
+ const compile_unit_cwd = try compile_unit.die.getAttrString(di, AT.comp_dir, di.section(.debug_line_str), compile_unit);
+ const line_info_offset = try compile_unit.die.getAttrSecOffset(AT.stmt_list);
+
+ var fbr: FixedBufferReader = .{ .buf = di.section(.debug_line).?, .endian = di.endian };
+ try fbr.seekTo(line_info_offset);
+
+ const unit_header = try readUnitHeader(&fbr, null);
+ if (unit_header.unit_length == 0) return missingDwarf();
+ const next_offset = unit_header.header_length + unit_header.unit_length;
+
+ const version = try fbr.readInt(u16);
+ if (version < 2) return badDwarf();
+
+ var addr_size: u8 = switch (unit_header.format) {
+ .@"32" => 4,
+ .@"64" => 8,
+ };
+ var seg_size: u8 = 0;
+ if (version >= 5) {
+ addr_size = try fbr.readByte();
+ seg_size = try fbr.readByte();
+ }
+
+ const prologue_length = try fbr.readAddress(unit_header.format);
+ const prog_start_offset = fbr.pos + prologue_length;
+
+ const minimum_instruction_length = try fbr.readByte();
+ if (minimum_instruction_length == 0) return badDwarf();
+
+ if (version >= 4) {
+ // maximum_operations_per_instruction
+ _ = try fbr.readByte();
+ }
+
+ const default_is_stmt = (try fbr.readByte()) != 0;
+ const line_base = try fbr.readByteSigned();
+
+ const line_range = try fbr.readByte();
+ if (line_range == 0) return badDwarf();
+
+ const opcode_base = try fbr.readByte();
+
+ const standard_opcode_lengths = try fbr.readBytes(opcode_base - 1);
+
+ var include_directories = std.ArrayList(FileEntry).init(allocator);
+ defer include_directories.deinit();
+ var file_entries = std.ArrayList(FileEntry).init(allocator);
+ defer file_entries.deinit();
+
+ if (version < 5) {
+ try include_directories.append(.{ .path = compile_unit_cwd });
+
+ while (true) {
+ const dir = try fbr.readBytesTo(0);
+ if (dir.len == 0) break;
+ try include_directories.append(.{ .path = dir });
+ }
+
+ while (true) {
+ const file_name = try fbr.readBytesTo(0);
+ if (file_name.len == 0) break;
+ const dir_index = try fbr.readUleb128(u32);
+ const mtime = try fbr.readUleb128(u64);
+ const size = try fbr.readUleb128(u64);
+ try file_entries.append(.{
+ .path = file_name,
+ .dir_index = dir_index,
+ .mtime = mtime,
+ .size = size,
+ });
+ }
+ } else {
+ const FileEntFmt = struct {
+ content_type_code: u8,
+ form_code: u16,
+ };
+ {
+ var dir_ent_fmt_buf: [10]FileEntFmt = undefined;
+ const directory_entry_format_count = try fbr.readByte();
+ if (directory_entry_format_count > dir_ent_fmt_buf.len) return badDwarf();
+ for (dir_ent_fmt_buf[0..directory_entry_format_count]) |*ent_fmt| {
+ ent_fmt.* = .{
+ .content_type_code = try fbr.readUleb128(u8),
+ .form_code = try fbr.readUleb128(u16),
+ };
+ }
+
+ const directories_count = try fbr.readUleb128(usize);
+ try include_directories.ensureUnusedCapacity(directories_count);
+ {
+ var i: usize = 0;
+ while (i < directories_count) : (i += 1) {
+ var e: FileEntry = .{ .path = &.{} };
+ for (dir_ent_fmt_buf[0..directory_entry_format_count]) |ent_fmt| {
+ const form_value = try parseFormValue(
+ &fbr,
+ ent_fmt.form_code,
+ unit_header.format,
+ null,
+ );
+ switch (ent_fmt.content_type_code) {
+ DW.LNCT.path => e.path = try form_value.getString(di.*),
+ DW.LNCT.directory_index => e.dir_index = try form_value.getUInt(u32),
+ DW.LNCT.timestamp => e.mtime = try form_value.getUInt(u64),
+ DW.LNCT.size => e.size = try form_value.getUInt(u64),
+ DW.LNCT.MD5 => e.md5 = switch (form_value) {
+ .data16 => |data16| data16.*,
+ else => return badDwarf(),
+ },
+ else => continue,
+ }
+ }
+ include_directories.appendAssumeCapacity(e);
+ }
+ }
+ }
+
+ var file_ent_fmt_buf: [10]FileEntFmt = undefined;
+ const file_name_entry_format_count = try fbr.readByte();
+ if (file_name_entry_format_count > file_ent_fmt_buf.len) return badDwarf();
+ for (file_ent_fmt_buf[0..file_name_entry_format_count]) |*ent_fmt| {
+ ent_fmt.* = .{
+ .content_type_code = try fbr.readUleb128(u8),
+ .form_code = try fbr.readUleb128(u16),
+ };
+ }
+
+ const file_names_count = try fbr.readUleb128(usize);
+ try file_entries.ensureUnusedCapacity(file_names_count);
+ {
+ var i: usize = 0;
+ while (i < file_names_count) : (i += 1) {
+ var e: FileEntry = .{ .path = &.{} };
+ for (file_ent_fmt_buf[0..file_name_entry_format_count]) |ent_fmt| {
+ const form_value = try parseFormValue(
+ &fbr,
+ ent_fmt.form_code,
+ unit_header.format,
+ null,
+ );
+ switch (ent_fmt.content_type_code) {
+ DW.LNCT.path => e.path = try form_value.getString(di.*),
+ DW.LNCT.directory_index => e.dir_index = try form_value.getUInt(u32),
+ DW.LNCT.timestamp => e.mtime = try form_value.getUInt(u64),
+ DW.LNCT.size => e.size = try form_value.getUInt(u64),
+ DW.LNCT.MD5 => e.md5 = switch (form_value) {
+ .data16 => |data16| data16.*,
+ else => return badDwarf(),
+ },
+ else => continue,
+ }
+ }
+ file_entries.appendAssumeCapacity(e);
+ }
+ }
+ }
+
+ var prog = LineNumberProgram.init(
+ default_is_stmt,
+ include_directories.items,
+ target_address,
+ version,
+ );
+
+ try fbr.seekTo(prog_start_offset);
+
+ const next_unit_pos = line_info_offset + next_offset;
+
+ while (fbr.pos < next_unit_pos) {
+ const opcode = try fbr.readByte();
+
+ if (opcode == DW.LNS.extended_op) {
+ const op_size = try fbr.readUleb128(u64);
+ if (op_size < 1) return badDwarf();
+ const sub_op = try fbr.readByte();
+ switch (sub_op) {
+ DW.LNE.end_sequence => {
+ prog.end_sequence = true;
+ if (try prog.checkLineMatch(allocator, file_entries.items)) |info| return info;
+ prog.reset();
+ },
+ DW.LNE.set_address => {
+ const addr = try fbr.readInt(usize);
+ prog.address = addr;
+ },
+ DW.LNE.define_file => {
+ const path = try fbr.readBytesTo(0);
+ const dir_index = try fbr.readUleb128(u32);
+ const mtime = try fbr.readUleb128(u64);
+ const size = try fbr.readUleb128(u64);
+ try file_entries.append(.{
+ .path = path,
+ .dir_index = dir_index,
+ .mtime = mtime,
+ .size = size,
+ });
+ },
+ else => try fbr.seekForward(op_size - 1),
+ }
+ } else if (opcode >= opcode_base) {
+ // special opcodes
+ const adjusted_opcode = opcode - opcode_base;
+ const inc_addr = minimum_instruction_length * (adjusted_opcode / line_range);
+ const inc_line = @as(i32, line_base) + @as(i32, adjusted_opcode % line_range);
+ prog.line += inc_line;
+ prog.address += inc_addr;
+ if (try prog.checkLineMatch(allocator, file_entries.items)) |info| return info;
+ prog.basic_block = false;
+ } else {
+ switch (opcode) {
+ DW.LNS.copy => {
+ if (try prog.checkLineMatch(allocator, file_entries.items)) |info| return info;
+ prog.basic_block = false;
+ },
+ DW.LNS.advance_pc => {
+ const arg = try fbr.readUleb128(usize);
+ prog.address += arg * minimum_instruction_length;
+ },
+ DW.LNS.advance_line => {
+ const arg = try fbr.readIleb128(i64);
+ prog.line += arg;
+ },
+ DW.LNS.set_file => {
+ const arg = try fbr.readUleb128(usize);
+ prog.file = arg;
+ },
+ DW.LNS.set_column => {
+ const arg = try fbr.readUleb128(u64);
+ prog.column = arg;
+ },
+ DW.LNS.negate_stmt => {
+ prog.is_stmt = !prog.is_stmt;
+ },
+ DW.LNS.set_basic_block => {
+ prog.basic_block = true;
+ },
+ DW.LNS.const_add_pc => {
+ const inc_addr = minimum_instruction_length * ((255 - opcode_base) / line_range);
+ prog.address += inc_addr;
+ },
+ DW.LNS.fixed_advance_pc => {
+ const arg = try fbr.readInt(u16);
+ prog.address += arg;
+ },
+ DW.LNS.set_prologue_end => {},
+ else => {
+ if (opcode - 1 >= standard_opcode_lengths.len) return badDwarf();
+ try fbr.seekForward(standard_opcode_lengths[opcode - 1]);
+ },
+ }
+ }
+ }
+
+ return missingDwarf();
+}
+
+fn getString(di: Dwarf, offset: u64) ![:0]const u8 {
+ return getStringGeneric(di.section(.debug_str), offset);
+}
+
+fn getLineString(di: Dwarf, offset: u64) ![:0]const u8 {
+ return getStringGeneric(di.section(.debug_line_str), offset);
+}
+
+fn readDebugAddr(di: Dwarf, compile_unit: CompileUnit, index: u64) !u64 {
+ const debug_addr = di.section(.debug_addr) orelse return badDwarf();
+
+ // addr_base points to the first item after the header, however we
+ // need to read the header to know the size of each item. Empirically,
+ // it may disagree with is_64 on the compile unit.
+ // The header is 8 or 12 bytes depending on is_64.
+ if (compile_unit.addr_base < 8) return badDwarf();
+
+ const version = readInt(u16, debug_addr[compile_unit.addr_base - 4 ..][0..2], di.endian);
+ if (version != 5) return badDwarf();
+
+ const addr_size = debug_addr[compile_unit.addr_base - 2];
+ const seg_size = debug_addr[compile_unit.addr_base - 1];
+
+ const byte_offset = @as(usize, @intCast(compile_unit.addr_base + (addr_size + seg_size) * index));
+ if (byte_offset + addr_size > debug_addr.len) return badDwarf();
+ return switch (addr_size) {
+ 1 => debug_addr[byte_offset],
+ 2 => readInt(u16, debug_addr[byte_offset..][0..2], di.endian),
+ 4 => readInt(u32, debug_addr[byte_offset..][0..4], di.endian),
+ 8 => readInt(u64, debug_addr[byte_offset..][0..8], di.endian),
+ else => badDwarf(),
+ };
+}
+
+/// If .eh_frame_hdr is present, then only the header needs to be parsed.
+///
+/// Otherwise, .eh_frame and .debug_frame are scanned and a sorted list
+/// of FDEs is built for binary searching during unwinding.
+pub fn scanAllUnwindInfo(di: *Dwarf, allocator: Allocator, base_address: usize) !void {
+ if (di.section(.eh_frame_hdr)) |eh_frame_hdr| blk: {
+ var fbr: FixedBufferReader = .{ .buf = eh_frame_hdr, .endian = native_endian };
+
+ const version = try fbr.readByte();
+ if (version != 1) break :blk;
+
+ const eh_frame_ptr_enc = try fbr.readByte();
+ if (eh_frame_ptr_enc == EH.PE.omit) break :blk;
+ const fde_count_enc = try fbr.readByte();
+ if (fde_count_enc == EH.PE.omit) break :blk;
+ const table_enc = try fbr.readByte();
+ if (table_enc == EH.PE.omit) break :blk;
+
+ const eh_frame_ptr = cast(usize, try readEhPointer(&fbr, eh_frame_ptr_enc, @sizeOf(usize), .{
+ .pc_rel_base = @intFromPtr(&eh_frame_hdr[fbr.pos]),
+ .follow_indirect = true,
+ }) orelse return badDwarf()) orelse return badDwarf();
+
+ const fde_count = cast(usize, try readEhPointer(&fbr, fde_count_enc, @sizeOf(usize), .{
+ .pc_rel_base = @intFromPtr(&eh_frame_hdr[fbr.pos]),
+ .follow_indirect = true,
+ }) orelse return badDwarf()) orelse return badDwarf();
+
+ const entry_size = try ExceptionFrameHeader.entrySize(table_enc);
+ const entries_len = fde_count * entry_size;
+ if (entries_len > eh_frame_hdr.len - fbr.pos) return badDwarf();
+
+ di.eh_frame_hdr = .{
+ .eh_frame_ptr = eh_frame_ptr,
+ .table_enc = table_enc,
+ .fde_count = fde_count,
+ .entries = eh_frame_hdr[fbr.pos..][0..entries_len],
+ };
+
+ // No need to scan .eh_frame, we have a binary search table already
+ return;
+ }
+
+ const frame_sections = [2]Section.Id{ .eh_frame, .debug_frame };
+ for (frame_sections) |frame_section| {
+ if (di.section(frame_section)) |section_data| {
+ var fbr: FixedBufferReader = .{ .buf = section_data, .endian = di.endian };
+ while (fbr.pos < fbr.buf.len) {
+ const entry_header = try EntryHeader.read(&fbr, null, frame_section);
+ switch (entry_header.type) {
+ .cie => {
+ const cie = try CommonInformationEntry.parse(
+ entry_header.entry_bytes,
+ di.sectionVirtualOffset(frame_section, base_address).?,
+ true,
+ entry_header.format,
+ frame_section,
+ entry_header.length_offset,
+ @sizeOf(usize),
+ di.endian,
+ );
+ try di.cie_map.put(allocator, entry_header.length_offset, cie);
+ },
+ .fde => |cie_offset| {
+ const cie = di.cie_map.get(cie_offset) orelse return badDwarf();
+ const fde = try FrameDescriptionEntry.parse(
+ entry_header.entry_bytes,
+ di.sectionVirtualOffset(frame_section, base_address).?,
+ true,
+ cie,
+ @sizeOf(usize),
+ di.endian,
+ );
+ try di.fde_list.append(allocator, fde);
+ },
+ .terminator => break,
+ }
+ }
+
+ std.mem.sortUnstable(FrameDescriptionEntry, di.fde_list.items, {}, struct {
+ fn lessThan(ctx: void, a: FrameDescriptionEntry, b: FrameDescriptionEntry) bool {
+ _ = ctx;
+ return a.pc_begin < b.pc_begin;
+ }
+ }.lessThan);
+ }
+ }
+}
+
+/// Unwind a stack frame using DWARF unwinding info, updating the register context.
+///
+/// If `.eh_frame_hdr` is available, it will be used to binary search for the FDE.
+/// Otherwise, a linear scan of `.eh_frame` and `.debug_frame` is done to find the FDE.
+///
+/// `explicit_fde_offset` is for cases where the FDE offset is known, such as when __unwind_info
+/// defers unwinding to DWARF. This is an offset into the `.eh_frame` section.
+pub fn unwindFrame(di: *const Dwarf, context: *UnwindContext, ma: *StackIterator.MemoryAccessor, explicit_fde_offset: ?usize) !usize {
+ if (!comptime abi.supportsUnwinding(builtin.target)) return error.UnsupportedCpuArchitecture;
+ if (context.pc == 0) return 0;
+
+ // Find the FDE and CIE
+ var cie: CommonInformationEntry = undefined;
+ var fde: FrameDescriptionEntry = undefined;
+
+ if (explicit_fde_offset) |fde_offset| {
+ const dwarf_section: Section.Id = .eh_frame;
+ const frame_section = di.section(dwarf_section) orelse return error.MissingFDE;
+ if (fde_offset >= frame_section.len) return error.MissingFDE;
+
+ var fbr: FixedBufferReader = .{
+ .buf = frame_section,
+ .pos = fde_offset,
+ .endian = di.endian,
+ };
+
+ const fde_entry_header = try EntryHeader.read(&fbr, null, dwarf_section);
+ if (fde_entry_header.type != .fde) return error.MissingFDE;
+
+ const cie_offset = fde_entry_header.type.fde;
+ try fbr.seekTo(cie_offset);
+
+ fbr.endian = native_endian;
+ const cie_entry_header = try EntryHeader.read(&fbr, null, dwarf_section);
+ if (cie_entry_header.type != .cie) return badDwarf();
+
+ cie = try CommonInformationEntry.parse(
+ cie_entry_header.entry_bytes,
+ 0,
+ true,
+ cie_entry_header.format,
+ dwarf_section,
+ cie_entry_header.length_offset,
+ @sizeOf(usize),
+ native_endian,
+ );
+
+ fde = try FrameDescriptionEntry.parse(
+ fde_entry_header.entry_bytes,
+ 0,
+ true,
+ cie,
+ @sizeOf(usize),
+ native_endian,
+ );
+ } else if (di.eh_frame_hdr) |header| {
+ const eh_frame_len = if (di.section(.eh_frame)) |eh_frame| eh_frame.len else null;
+ try header.findEntry(
+ ma,
+ eh_frame_len,
+ @intFromPtr(di.section(.eh_frame_hdr).?.ptr),
+ context.pc,
+ &cie,
+ &fde,
+ );
+ } else {
+ const index = std.sort.binarySearch(FrameDescriptionEntry, context.pc, di.fde_list.items, {}, struct {
+ pub fn compareFn(_: void, pc: usize, mid_item: FrameDescriptionEntry) std.math.Order {
+ if (pc < mid_item.pc_begin) return .lt;
+
+ const range_end = mid_item.pc_begin + mid_item.pc_range;
+ if (pc < range_end) return .eq;
+
+ return .gt;
+ }
+ }.compareFn);
+
+ fde = if (index) |i| di.fde_list.items[i] else return error.MissingFDE;
+ cie = di.cie_map.get(fde.cie_length_offset) orelse return error.MissingCIE;
+ }
+
+ var expression_context: expression.Context = .{
+ .format = cie.format,
+ .memory_accessor = ma,
+ .compile_unit = di.findCompileUnit(fde.pc_begin) catch null,
+ .thread_context = context.thread_context,
+ .reg_context = context.reg_context,
+ .cfa = context.cfa,
+ };
+
+ context.vm.reset();
+ context.reg_context.eh_frame = cie.version != 4;
+ context.reg_context.is_macho = di.is_macho;
+
+ const row = try context.vm.runToNative(context.allocator, context.pc, cie, fde);
+ context.cfa = switch (row.cfa.rule) {
+ .val_offset => |offset| blk: {
+ const register = row.cfa.register orelse return error.InvalidCFARule;
+ const value = readInt(usize, (try abi.regBytes(context.thread_context, register, context.reg_context))[0..@sizeOf(usize)], native_endian);
+ break :blk try call_frame.applyOffset(value, offset);
+ },
+ .expression => |expr| blk: {
+ context.stack_machine.reset();
+ const value = try context.stack_machine.run(
+ expr,
+ context.allocator,
+ expression_context,
+ context.cfa,
+ );
+
+ if (value) |v| {
+ if (v != .generic) return error.InvalidExpressionValue;
+ break :blk v.generic;
+ } else return error.NoExpressionValue;
+ },
+ else => return error.InvalidCFARule,
+ };
+
+ if (ma.load(usize, context.cfa.?) == null) return error.InvalidCFA;
+ expression_context.cfa = context.cfa;
+
+ // Buffering the modifications is done because copying the thread context is not portable,
+ // some implementations (ie. darwin) use internal pointers to the mcontext.
+ var arena = std.heap.ArenaAllocator.init(context.allocator);
+ defer arena.deinit();
+ const update_allocator = arena.allocator();
+
+ const RegisterUpdate = struct {
+ // Backed by thread_context
+ dest: []u8,
+ // Backed by arena
+ src: []const u8,
+ prev: ?*@This(),
+ };
+
+ var update_tail: ?*RegisterUpdate = null;
+ var has_return_address = true;
+ for (context.vm.rowColumns(row)) |column| {
+ if (column.register) |register| {
+ if (register == cie.return_address_register) {
+ has_return_address = column.rule != .undefined;
+ }
+
+ const dest = try abi.regBytes(context.thread_context, register, context.reg_context);
+ const src = try update_allocator.alloc(u8, dest.len);
+
+ const prev = update_tail;
+ update_tail = try update_allocator.create(RegisterUpdate);
+ update_tail.?.* = .{
+ .dest = dest,
+ .src = src,
+ .prev = prev,
+ };
+
+ try column.resolveValue(
+ context,
+ expression_context,
+ ma,
+ src,
+ );
+ }
+ }
+
+ // On all implemented architectures, the CFA is defined as being the previous frame's SP
+ (try abi.regValueNative(usize, context.thread_context, abi.spRegNum(context.reg_context), context.reg_context)).* = context.cfa.?;
+
+ while (update_tail) |tail| {
+ @memcpy(tail.dest, tail.src);
+ update_tail = tail.prev;
+ }
+
+ if (has_return_address) {
+ context.pc = abi.stripInstructionPtrAuthCode(readInt(usize, (try abi.regBytes(
+ context.thread_context,
+ cie.return_address_register,
+ context.reg_context,
+ ))[0..@sizeOf(usize)], native_endian));
+ } else {
+ context.pc = 0;
+ }
+
+ (try abi.regValueNative(usize, context.thread_context, abi.ipRegNum(), context.reg_context)).* = context.pc;
+
+ // The call instruction will have pushed the address of the instruction that follows the call as the return address.
+ // This next instruction may be past the end of the function if the caller was `noreturn` (ie. the last instruction in
+ // the function was the call). If we were to look up an FDE entry using the return address directly, it could end up
+ // either not finding an FDE at all, or using the next FDE in the program, producing incorrect results. To prevent this,
+ // we subtract one so that the next lookup is guaranteed to land inside the
+ //
+ // The exception to this rule is signal frames, where we return execution would be returned to the instruction
+ // that triggered the handler.
+ const return_address = context.pc;
+ if (context.pc > 0 and !cie.isSignalFrame()) context.pc -= 1;
+
+ return return_address;
+}
+
+fn parseFormValue(
+ fbr: *FixedBufferReader,
+ form_id: u64,
+ format: Format,
+ implicit_const: ?i64,
+) anyerror!FormValue {
+ return switch (form_id) {
+ FORM.addr => .{ .addr = try fbr.readAddress(switch (@bitSizeOf(usize)) {
+ 32 => .@"32",
+ 64 => .@"64",
+ else => @compileError("unsupported @sizeOf(usize)"),
+ }) },
+ FORM.addrx1 => .{ .addrx = try fbr.readInt(u8) },
+ FORM.addrx2 => .{ .addrx = try fbr.readInt(u16) },
+ FORM.addrx3 => .{ .addrx = try fbr.readInt(u24) },
+ FORM.addrx4 => .{ .addrx = try fbr.readInt(u32) },
+ FORM.addrx => .{ .addrx = try fbr.readUleb128(usize) },
+
+ FORM.block1,
+ FORM.block2,
+ FORM.block4,
+ FORM.block,
+ => .{ .block = try fbr.readBytes(switch (form_id) {
+ FORM.block1 => try fbr.readInt(u8),
+ FORM.block2 => try fbr.readInt(u16),
+ FORM.block4 => try fbr.readInt(u32),
+ FORM.block => try fbr.readUleb128(usize),
+ else => unreachable,
+ }) },
+
+ FORM.data1 => .{ .udata = try fbr.readInt(u8) },
+ FORM.data2 => .{ .udata = try fbr.readInt(u16) },
+ FORM.data4 => .{ .udata = try fbr.readInt(u32) },
+ FORM.data8 => .{ .udata = try fbr.readInt(u64) },
+ FORM.data16 => .{ .data16 = (try fbr.readBytes(16))[0..16] },
+ FORM.udata => .{ .udata = try fbr.readUleb128(u64) },
+ FORM.sdata => .{ .sdata = try fbr.readIleb128(i64) },
+ FORM.exprloc => .{ .exprloc = try fbr.readBytes(try fbr.readUleb128(usize)) },
+ FORM.flag => .{ .flag = (try fbr.readByte()) != 0 },
+ FORM.flag_present => .{ .flag = true },
+ FORM.sec_offset => .{ .sec_offset = try fbr.readAddress(format) },
+
+ FORM.ref1 => .{ .ref = try fbr.readInt(u8) },
+ FORM.ref2 => .{ .ref = try fbr.readInt(u16) },
+ FORM.ref4 => .{ .ref = try fbr.readInt(u32) },
+ FORM.ref8 => .{ .ref = try fbr.readInt(u64) },
+ FORM.ref_udata => .{ .ref = try fbr.readUleb128(u64) },
+
+ FORM.ref_addr => .{ .ref_addr = try fbr.readAddress(format) },
+ FORM.ref_sig8 => .{ .ref = try fbr.readInt(u64) },
+
+ FORM.string => .{ .string = try fbr.readBytesTo(0) },
+ FORM.strp => .{ .strp = try fbr.readAddress(format) },
+ FORM.strx1 => .{ .strx = try fbr.readInt(u8) },
+ FORM.strx2 => .{ .strx = try fbr.readInt(u16) },
+ FORM.strx3 => .{ .strx = try fbr.readInt(u24) },
+ FORM.strx4 => .{ .strx = try fbr.readInt(u32) },
+ FORM.strx => .{ .strx = try fbr.readUleb128(usize) },
+ FORM.line_strp => .{ .line_strp = try fbr.readAddress(format) },
+ FORM.indirect => parseFormValue(fbr, try fbr.readUleb128(u64), format, implicit_const),
+ FORM.implicit_const => .{ .sdata = implicit_const orelse return badDwarf() },
+ FORM.loclistx => .{ .loclistx = try fbr.readUleb128(u64) },
+ FORM.rnglistx => .{ .rnglistx = try fbr.readUleb128(u64) },
+ else => {
+ //debug.print("unrecognized form id: {x}\n", .{form_id});
+ return badDwarf();
+ },
+ };
+}
+
+const FileEntry = struct {
+ path: []const u8,
+ dir_index: u32 = 0,
+ mtime: u64 = 0,
+ size: u64 = 0,
+ md5: [16]u8 = [1]u8{0} ** 16,
+};
+
+const LineNumberProgram = struct {
+ address: u64,
+ file: usize,
+ line: i64,
+ column: u64,
+ version: u16,
+ is_stmt: bool,
+ basic_block: bool,
+ end_sequence: bool,
+
+ default_is_stmt: bool,
+ target_address: u64,
+ include_dirs: []const FileEntry,
+
+ prev_valid: bool,
+ prev_address: u64,
+ prev_file: usize,
+ prev_line: i64,
+ prev_column: u64,
+ prev_is_stmt: bool,
+ prev_basic_block: bool,
+ prev_end_sequence: bool,
+
+ // Reset the state machine following the DWARF specification
+ pub fn reset(self: *LineNumberProgram) void {
+ self.address = 0;
+ self.file = 1;
+ self.line = 1;
+ self.column = 0;
+ self.is_stmt = self.default_is_stmt;
+ self.basic_block = false;
+ self.end_sequence = false;
+ // Invalidate all the remaining fields
+ self.prev_valid = false;
+ self.prev_address = 0;
+ self.prev_file = undefined;
+ self.prev_line = undefined;
+ self.prev_column = undefined;
+ self.prev_is_stmt = undefined;
+ self.prev_basic_block = undefined;
+ self.prev_end_sequence = undefined;
+ }
+
+ pub fn init(
+ is_stmt: bool,
+ include_dirs: []const FileEntry,
+ target_address: u64,
+ version: u16,
+ ) LineNumberProgram {
+ return LineNumberProgram{
+ .address = 0,
+ .file = 1,
+ .line = 1,
+ .column = 0,
+ .version = version,
+ .is_stmt = is_stmt,
+ .basic_block = false,
+ .end_sequence = false,
+ .include_dirs = include_dirs,
+ .default_is_stmt = is_stmt,
+ .target_address = target_address,
+ .prev_valid = false,
+ .prev_address = 0,
+ .prev_file = undefined,
+ .prev_line = undefined,
+ .prev_column = undefined,
+ .prev_is_stmt = undefined,
+ .prev_basic_block = undefined,
+ .prev_end_sequence = undefined,
+ };
+ }
+
+ pub fn checkLineMatch(
+ self: *LineNumberProgram,
+ allocator: Allocator,
+ file_entries: []const FileEntry,
+ ) !?std.debug.LineInfo {
+ if (self.prev_valid and
+ self.target_address >= self.prev_address and
+ self.target_address < self.address)
+ {
+ const file_index = if (self.version >= 5) self.prev_file else i: {
+ if (self.prev_file == 0) return missingDwarf();
+ break :i self.prev_file - 1;
+ };
+
+ if (file_index >= file_entries.len) return badDwarf();
+ const file_entry = &file_entries[file_index];
+
+ if (file_entry.dir_index >= self.include_dirs.len) return badDwarf();
+ const dir_name = self.include_dirs[file_entry.dir_index].path;
+
+ const file_name = try std.fs.path.join(allocator, &[_][]const u8{
+ dir_name, file_entry.path,
+ });
+
+ return std.debug.LineInfo{
+ .line = if (self.prev_line >= 0) @as(u64, @intCast(self.prev_line)) else 0,
+ .column = self.prev_column,
+ .file_name = file_name,
+ };
+ }
+
+ self.prev_valid = true;
+ self.prev_address = self.address;
+ self.prev_file = self.file;
+ self.prev_line = self.line;
+ self.prev_column = self.column;
+ self.prev_is_stmt = self.is_stmt;
+ self.prev_basic_block = self.basic_block;
+ self.prev_end_sequence = self.end_sequence;
+ return null;
+ }
+};
+
+const UnitHeader = struct {
+ format: Format,
+ header_length: u4,
+ unit_length: u64,
+};
+fn readUnitHeader(fbr: *FixedBufferReader, opt_ma: ?*StackIterator.MemoryAccessor) !UnitHeader {
+ return switch (try if (opt_ma) |ma| fbr.readIntChecked(u32, ma) else fbr.readInt(u32)) {
+ 0...0xfffffff0 - 1 => |unit_length| .{
+ .format = .@"32",
+ .header_length = 4,
+ .unit_length = unit_length,
+ },
+ 0xfffffff0...0xffffffff - 1 => badDwarf(),
+ 0xffffffff => .{
+ .format = .@"64",
+ .header_length = 12,
+ .unit_length = try if (opt_ma) |ma| fbr.readIntChecked(u64, ma) else fbr.readInt(u64),
+ },
+ };
+}
+
+/// Returns the DWARF register number for an x86_64 register number found in compact unwind info
+fn compactUnwindToDwarfRegNumber(unwind_reg_number: u3) !u8 {
+ return switch (unwind_reg_number) {
+ 1 => 3, // RBX
+ 2 => 12, // R12
+ 3 => 13, // R13
+ 4 => 14, // R14
+ 5 => 15, // R15
+ 6 => 6, // RBP
+ else => error.InvalidUnwindRegisterNumber,
+ };
+}
+
+/// This function is to make it handy to comment out the return and make it
+/// into a crash when working on this file.
+fn badDwarf() error{InvalidDebugInfo} {
+ //if (true) @panic("badDwarf"); // can be handy to uncomment when working on this file
+ return error.InvalidDebugInfo;
+}
+
+fn missingDwarf() error{MissingDebugInfo} {
+ //if (true) @panic("missingDwarf"); // can be handy to uncomment when working on this file
+ return error.MissingDebugInfo;
+}
+
+fn getStringGeneric(opt_str: ?[]const u8, offset: u64) ![:0]const u8 {
+ const str = opt_str orelse return badDwarf();
+ if (offset > str.len) return badDwarf();
+ const casted_offset = cast(usize, offset) orelse return badDwarf();
+ // Valid strings always have a terminating zero byte
+ const last = std.mem.indexOfScalarPos(u8, str, casted_offset, 0) orelse return badDwarf();
+ return str[casted_offset..last :0];
+}
+
+// Reading debug info needs to be fast, even when compiled in debug mode,
+// so avoid using a `std.io.FixedBufferStream` which is too slow.
+pub const FixedBufferReader = struct {
+ buf: []const u8,
+ pos: usize = 0,
+ endian: std.builtin.Endian,
+
+ pub const Error = error{ EndOfBuffer, Overflow, InvalidBuffer };
+
+ fn seekTo(fbr: *FixedBufferReader, pos: u64) Error!void {
+ if (pos > fbr.buf.len) return error.EndOfBuffer;
+ fbr.pos = @intCast(pos);
+ }
+
+ fn seekForward(fbr: *FixedBufferReader, amount: u64) Error!void {
+ if (fbr.buf.len - fbr.pos < amount) return error.EndOfBuffer;
+ fbr.pos += @intCast(amount);
+ }
+
+ pub inline fn readByte(fbr: *FixedBufferReader) Error!u8 {
+ if (fbr.pos >= fbr.buf.len) return error.EndOfBuffer;
+ defer fbr.pos += 1;
+ return fbr.buf[fbr.pos];
+ }
+
+ fn readByteSigned(fbr: *FixedBufferReader) Error!i8 {
+ return @bitCast(try fbr.readByte());
+ }
+
+ fn readInt(fbr: *FixedBufferReader, comptime T: type) Error!T {
+ const size = @divExact(@typeInfo(T).Int.bits, 8);
+ if (fbr.buf.len - fbr.pos < size) return error.EndOfBuffer;
+ defer fbr.pos += size;
+ return std.mem.readInt(T, fbr.buf[fbr.pos..][0..size], fbr.endian);
+ }
+
+ fn readIntChecked(
+ fbr: *FixedBufferReader,
+ comptime T: type,
+ ma: *std.debug.StackIterator.MemoryAccessor,
+ ) Error!T {
+ if (ma.load(T, @intFromPtr(fbr.buf[fbr.pos..].ptr)) == null)
+ return error.InvalidBuffer;
+
+ return fbr.readInt(T);
+ }
+
+ fn readUleb128(fbr: *FixedBufferReader, comptime T: type) Error!T {
+ return std.leb.readUleb128(T, fbr);
+ }
+
+ fn readIleb128(fbr: *FixedBufferReader, comptime T: type) Error!T {
+ return std.leb.readIleb128(T, fbr);
+ }
+
+ fn readAddress(fbr: *FixedBufferReader, format: Format) Error!u64 {
+ return switch (format) {
+ .@"32" => try fbr.readInt(u32),
+ .@"64" => try fbr.readInt(u64),
+ };
+ }
+
+ fn readAddressChecked(
+ fbr: *FixedBufferReader,
+ format: Format,
+ ma: *std.debug.StackIterator.MemoryAccessor,
+ ) Error!u64 {
+ return switch (format) {
+ .@"32" => try fbr.readIntChecked(u32, ma),
+ .@"64" => try fbr.readIntChecked(u64, ma),
+ };
+ }
+
+ fn readBytes(fbr: *FixedBufferReader, len: usize) Error![]const u8 {
+ if (fbr.buf.len - fbr.pos < len) return error.EndOfBuffer;
+ defer fbr.pos += len;
+ return fbr.buf[fbr.pos..][0..len];
+ }
+
+ fn readBytesTo(fbr: *FixedBufferReader, comptime sentinel: u8) Error![:sentinel]const u8 {
+ const end = @call(.always_inline, std.mem.indexOfScalarPos, .{
+ u8,
+ fbr.buf,
+ fbr.pos,
+ sentinel,
+ }) orelse return error.EndOfBuffer;
+ defer fbr.pos = end + 1;
+ return fbr.buf[fbr.pos..end :sentinel];
+ }
+};
+
+/// Unwind a frame using MachO compact unwind info (from __unwind_info).
+/// If the compact encoding can't encode a way to unwind a frame, it will
+/// defer unwinding to DWARF, in which case `.eh_frame` will be used if available.
+pub fn unwindFrameMachO(
+ context: *UnwindContext,
+ ma: *StackIterator.MemoryAccessor,
+ unwind_info: []const u8,
+ eh_frame: ?[]const u8,
+ module_base_address: usize,
+) !usize {
+ const macho = std.macho;
+
+ const header = std.mem.bytesAsValue(
+ macho.unwind_info_section_header,
+ unwind_info[0..@sizeOf(macho.unwind_info_section_header)],
+ );
+ const indices = std.mem.bytesAsSlice(
+ macho.unwind_info_section_header_index_entry,
+ unwind_info[header.indexSectionOffset..][0 .. header.indexCount * @sizeOf(macho.unwind_info_section_header_index_entry)],
+ );
+ if (indices.len == 0) return error.MissingUnwindInfo;
+
+ const mapped_pc = context.pc - module_base_address;
+ const second_level_index = blk: {
+ var left: usize = 0;
+ var len: usize = indices.len;
+
+ while (len > 1) {
+ const mid = left + len / 2;
+ const offset = indices[mid].functionOffset;
+ if (mapped_pc < offset) {
+ len /= 2;
+ } else {
+ left = mid;
+ if (mapped_pc == offset) break;
+ len -= len / 2;
+ }
+ }
+
+ // Last index is a sentinel containing the highest address as its functionOffset
+ if (indices[left].secondLevelPagesSectionOffset == 0) return error.MissingUnwindInfo;
+ break :blk &indices[left];
+ };
+
+ const common_encodings = std.mem.bytesAsSlice(
+ macho.compact_unwind_encoding_t,
+ unwind_info[header.commonEncodingsArraySectionOffset..][0 .. header.commonEncodingsArrayCount * @sizeOf(macho.compact_unwind_encoding_t)],
+ );
+
+ const start_offset = second_level_index.secondLevelPagesSectionOffset;
+ const kind = std.mem.bytesAsValue(
+ macho.UNWIND_SECOND_LEVEL,
+ unwind_info[start_offset..][0..@sizeOf(macho.UNWIND_SECOND_LEVEL)],
+ );
+
+ const entry: struct {
+ function_offset: usize,
+ raw_encoding: u32,
+ } = switch (kind.*) {
+ .REGULAR => blk: {
+ const page_header = std.mem.bytesAsValue(
+ macho.unwind_info_regular_second_level_page_header,
+ unwind_info[start_offset..][0..@sizeOf(macho.unwind_info_regular_second_level_page_header)],
+ );
+
+ const entries = std.mem.bytesAsSlice(
+ macho.unwind_info_regular_second_level_entry,
+ unwind_info[start_offset + page_header.entryPageOffset ..][0 .. page_header.entryCount * @sizeOf(macho.unwind_info_regular_second_level_entry)],
+ );
+ if (entries.len == 0) return error.InvalidUnwindInfo;
+
+ var left: usize = 0;
+ var len: usize = entries.len;
+ while (len > 1) {
+ const mid = left + len / 2;
+ const offset = entries[mid].functionOffset;
+ if (mapped_pc < offset) {
+ len /= 2;
+ } else {
+ left = mid;
+ if (mapped_pc == offset) break;
+ len -= len / 2;
+ }
+ }
+
+ break :blk .{
+ .function_offset = entries[left].functionOffset,
+ .raw_encoding = entries[left].encoding,
+ };
+ },
+ .COMPRESSED => blk: {
+ const page_header = std.mem.bytesAsValue(
+ macho.unwind_info_compressed_second_level_page_header,
+ unwind_info[start_offset..][0..@sizeOf(macho.unwind_info_compressed_second_level_page_header)],
+ );
+
+ const entries = std.mem.bytesAsSlice(
+ macho.UnwindInfoCompressedEntry,
+ unwind_info[start_offset + page_header.entryPageOffset ..][0 .. page_header.entryCount * @sizeOf(macho.UnwindInfoCompressedEntry)],
+ );
+ if (entries.len == 0) return error.InvalidUnwindInfo;
+
+ var left: usize = 0;
+ var len: usize = entries.len;
+ while (len > 1) {
+ const mid = left + len / 2;
+ const offset = second_level_index.functionOffset + entries[mid].funcOffset;
+ if (mapped_pc < offset) {
+ len /= 2;
+ } else {
+ left = mid;
+ if (mapped_pc == offset) break;
+ len -= len / 2;
+ }
+ }
+
+ const entry = entries[left];
+ const function_offset = second_level_index.functionOffset + entry.funcOffset;
+ if (entry.encodingIndex < header.commonEncodingsArrayCount) {
+ if (entry.encodingIndex >= common_encodings.len) return error.InvalidUnwindInfo;
+ break :blk .{
+ .function_offset = function_offset,
+ .raw_encoding = common_encodings[entry.encodingIndex],
+ };
+ } else {
+ const local_index = try std.math.sub(
+ u8,
+ entry.encodingIndex,
+ cast(u8, header.commonEncodingsArrayCount) orelse return error.InvalidUnwindInfo,
+ );
+ const local_encodings = std.mem.bytesAsSlice(
+ macho.compact_unwind_encoding_t,
+ unwind_info[start_offset + page_header.encodingsPageOffset ..][0 .. page_header.encodingsCount * @sizeOf(macho.compact_unwind_encoding_t)],
+ );
+ if (local_index >= local_encodings.len) return error.InvalidUnwindInfo;
+ break :blk .{
+ .function_offset = function_offset,
+ .raw_encoding = local_encodings[local_index],
+ };
+ }
+ },
+ else => return error.InvalidUnwindInfo,
+ };
+
+ if (entry.raw_encoding == 0) return error.NoUnwindInfo;
+ const reg_context = abi.RegisterContext{
+ .eh_frame = false,
+ .is_macho = true,
+ };
+
+ const encoding: macho.CompactUnwindEncoding = @bitCast(entry.raw_encoding);
+ const new_ip = switch (builtin.cpu.arch) {
+ .x86_64 => switch (encoding.mode.x86_64) {
+ .OLD => return error.UnimplementedUnwindEncoding,
+ .RBP_FRAME => blk: {
+ const regs: [5]u3 = .{
+ encoding.value.x86_64.frame.reg0,
+ encoding.value.x86_64.frame.reg1,
+ encoding.value.x86_64.frame.reg2,
+ encoding.value.x86_64.frame.reg3,
+ encoding.value.x86_64.frame.reg4,
+ };
+
+ const frame_offset = encoding.value.x86_64.frame.frame_offset * @sizeOf(usize);
+ var max_reg: usize = 0;
+ inline for (regs, 0..) |reg, i| {
+ if (reg > 0) max_reg = i;
+ }
+
+ const fp = (try abi.regValueNative(usize, context.thread_context, abi.fpRegNum(reg_context), reg_context)).*;
+ const new_sp = fp + 2 * @sizeOf(usize);
+
+ // Verify the stack range we're about to read register values from
+ if (ma.load(usize, new_sp) == null or ma.load(usize, fp - frame_offset + max_reg * @sizeOf(usize)) == null) return error.InvalidUnwindInfo;
+
+ const ip_ptr = fp + @sizeOf(usize);
+ const new_ip = @as(*const usize, @ptrFromInt(ip_ptr)).*;
+ const new_fp = @as(*const usize, @ptrFromInt(fp)).*;
+
+ (try abi.regValueNative(usize, context.thread_context, abi.fpRegNum(reg_context), reg_context)).* = new_fp;
+ (try abi.regValueNative(usize, context.thread_context, abi.spRegNum(reg_context), reg_context)).* = new_sp;
+ (try abi.regValueNative(usize, context.thread_context, abi.ipRegNum(), reg_context)).* = new_ip;
+
+ for (regs, 0..) |reg, i| {
+ if (reg == 0) continue;
+ const addr = fp - frame_offset + i * @sizeOf(usize);
+ const reg_number = try compactUnwindToDwarfRegNumber(reg);
+ (try abi.regValueNative(usize, context.thread_context, reg_number, reg_context)).* = @as(*const usize, @ptrFromInt(addr)).*;
+ }
+
+ break :blk new_ip;
+ },
+ .STACK_IMMD,
+ .STACK_IND,
+ => blk: {
+ const sp = (try abi.regValueNative(usize, context.thread_context, abi.spRegNum(reg_context), reg_context)).*;
+ const stack_size = if (encoding.mode.x86_64 == .STACK_IMMD)
+ @as(usize, encoding.value.x86_64.frameless.stack.direct.stack_size) * @sizeOf(usize)
+ else stack_size: {
+ // In .STACK_IND, the stack size is inferred from the subq instruction at the beginning of the function.
+ const sub_offset_addr =
+ module_base_address +
+ entry.function_offset +
+ encoding.value.x86_64.frameless.stack.indirect.sub_offset;
+ if (ma.load(usize, sub_offset_addr) == null) return error.InvalidUnwindInfo;
+
+ // `sub_offset_addr` points to the offset of the literal within the instruction
+ const sub_operand = @as(*align(1) const u32, @ptrFromInt(sub_offset_addr)).*;
+ break :stack_size sub_operand + @sizeOf(usize) * @as(usize, encoding.value.x86_64.frameless.stack.indirect.stack_adjust);
+ };
+
+ // Decode the Lehmer-coded sequence of registers.
+ // For a description of the encoding see lib/libc/include/any-macos.13-any/mach-o/compact_unwind_encoding.h
+
+ // Decode the variable-based permutation number into its digits. Each digit represents
+ // an index into the list of register numbers that weren't yet used in the sequence at
+ // the time the digit was added.
+ const reg_count = encoding.value.x86_64.frameless.stack_reg_count;
+ const ip_ptr = if (reg_count > 0) reg_blk: {
+ var digits: [6]u3 = undefined;
+ var accumulator: usize = encoding.value.x86_64.frameless.stack_reg_permutation;
+ var base: usize = 2;
+ for (0..reg_count) |i| {
+ const div = accumulator / base;
+ digits[digits.len - 1 - i] = @intCast(accumulator - base * div);
+ accumulator = div;
+ base += 1;
+ }
+
+ const reg_numbers = [_]u3{ 1, 2, 3, 4, 5, 6 };
+ var registers: [reg_numbers.len]u3 = undefined;
+ var used_indices = [_]bool{false} ** reg_numbers.len;
+ for (digits[digits.len - reg_count ..], 0..) |target_unused_index, i| {
+ var unused_count: u8 = 0;
+ const unused_index = for (used_indices, 0..) |used, index| {
+ if (!used) {
+ if (target_unused_index == unused_count) break index;
+ unused_count += 1;
+ }
+ } else unreachable;
+
+ registers[i] = reg_numbers[unused_index];
+ used_indices[unused_index] = true;
+ }
+
+ var reg_addr = sp + stack_size - @sizeOf(usize) * @as(usize, reg_count + 1);
+ if (ma.load(usize, reg_addr) == null) return error.InvalidUnwindInfo;
+ for (0..reg_count) |i| {
+ const reg_number = try compactUnwindToDwarfRegNumber(registers[i]);
+ (try abi.regValueNative(usize, context.thread_context, reg_number, reg_context)).* = @as(*const usize, @ptrFromInt(reg_addr)).*;
+ reg_addr += @sizeOf(usize);
+ }
+
+ break :reg_blk reg_addr;
+ } else sp + stack_size - @sizeOf(usize);
+
+ const new_ip = @as(*const usize, @ptrFromInt(ip_ptr)).*;
+ const new_sp = ip_ptr + @sizeOf(usize);
+ if (ma.load(usize, new_sp) == null) return error.InvalidUnwindInfo;
+
+ (try abi.regValueNative(usize, context.thread_context, abi.spRegNum(reg_context), reg_context)).* = new_sp;
+ (try abi.regValueNative(usize, context.thread_context, abi.ipRegNum(), reg_context)).* = new_ip;
+
+ break :blk new_ip;
+ },
+ .DWARF => {
+ return unwindFrameMachODwarf(context, ma, eh_frame orelse return error.MissingEhFrame, @intCast(encoding.value.x86_64.dwarf));
+ },
+ },
+ .aarch64 => switch (encoding.mode.arm64) {
+ .OLD => return error.UnimplementedUnwindEncoding,
+ .FRAMELESS => blk: {
+ const sp = (try abi.regValueNative(usize, context.thread_context, abi.spRegNum(reg_context), reg_context)).*;
+ const new_sp = sp + encoding.value.arm64.frameless.stack_size * 16;
+ const new_ip = (try abi.regValueNative(usize, context.thread_context, 30, reg_context)).*;
+ if (ma.load(usize, new_sp) == null) return error.InvalidUnwindInfo;
+ (try abi.regValueNative(usize, context.thread_context, abi.spRegNum(reg_context), reg_context)).* = new_sp;
+ break :blk new_ip;
+ },
+ .DWARF => {
+ return unwindFrameMachODwarf(context, ma, eh_frame orelse return error.MissingEhFrame, @intCast(encoding.value.arm64.dwarf));
+ },
+ .FRAME => blk: {
+ const fp = (try abi.regValueNative(usize, context.thread_context, abi.fpRegNum(reg_context), reg_context)).*;
+ const new_sp = fp + 16;
+ const ip_ptr = fp + @sizeOf(usize);
+
+ const num_restored_pairs: usize =
+ @popCount(@as(u5, @bitCast(encoding.value.arm64.frame.x_reg_pairs))) +
+ @popCount(@as(u4, @bitCast(encoding.value.arm64.frame.d_reg_pairs)));
+ const min_reg_addr = fp - num_restored_pairs * 2 * @sizeOf(usize);
+
+ if (ma.load(usize, new_sp) == null or ma.load(usize, min_reg_addr) == null) return error.InvalidUnwindInfo;
+
+ var reg_addr = fp - @sizeOf(usize);
+ inline for (@typeInfo(@TypeOf(encoding.value.arm64.frame.x_reg_pairs)).Struct.fields, 0..) |field, i| {
+ if (@field(encoding.value.arm64.frame.x_reg_pairs, field.name) != 0) {
+ (try abi.regValueNative(usize, context.thread_context, 19 + i, reg_context)).* = @as(*const usize, @ptrFromInt(reg_addr)).*;
+ reg_addr += @sizeOf(usize);
+ (try abi.regValueNative(usize, context.thread_context, 20 + i, reg_context)).* = @as(*const usize, @ptrFromInt(reg_addr)).*;
+ reg_addr += @sizeOf(usize);
+ }
+ }
+
+ inline for (@typeInfo(@TypeOf(encoding.value.arm64.frame.d_reg_pairs)).Struct.fields, 0..) |field, i| {
+ if (@field(encoding.value.arm64.frame.d_reg_pairs, field.name) != 0) {
+ // Only the lower half of the 128-bit V registers are restored during unwinding
+ @memcpy(
+ try abi.regBytes(context.thread_context, 64 + 8 + i, context.reg_context),
+ std.mem.asBytes(@as(*const usize, @ptrFromInt(reg_addr))),
+ );
+ reg_addr += @sizeOf(usize);
+ @memcpy(
+ try abi.regBytes(context.thread_context, 64 + 9 + i, context.reg_context),
+ std.mem.asBytes(@as(*const usize, @ptrFromInt(reg_addr))),
+ );
+ reg_addr += @sizeOf(usize);
+ }
+ }
+
+ const new_ip = @as(*const usize, @ptrFromInt(ip_ptr)).*;
+ const new_fp = @as(*const usize, @ptrFromInt(fp)).*;
+
+ (try abi.regValueNative(usize, context.thread_context, abi.fpRegNum(reg_context), reg_context)).* = new_fp;
+ (try abi.regValueNative(usize, context.thread_context, abi.ipRegNum(), reg_context)).* = new_ip;
+
+ break :blk new_ip;
+ },
+ },
+ else => return error.UnimplementedArch,
+ };
+
+ context.pc = abi.stripInstructionPtrAuthCode(new_ip);
+ if (context.pc > 0) context.pc -= 1;
+ return new_ip;
+}
+
+fn unwindFrameMachODwarf(
+ context: *UnwindContext,
+ ma: *std.debug.StackIterator.MemoryAccessor,
+ eh_frame: []const u8,
+ fde_offset: usize,
+) !usize {
+ var di = Dwarf{
+ .endian = native_endian,
+ .is_macho = true,
+ };
+ defer di.deinit(context.allocator);
+
+ di.sections[@intFromEnum(Section.Id.eh_frame)] = .{
+ .data = eh_frame,
+ .owned = false,
+ };
+
+ return di.unwindFrame(context, ma, fde_offset);
+}
+
+const EhPointerContext = struct {
+ // The address of the pointer field itself
+ pc_rel_base: u64,
+
+ // Whether or not to follow indirect pointers. This should only be
+ // used when decoding pointers at runtime using the current process's
+ // debug info
+ follow_indirect: bool,
+
+ // These relative addressing modes are only used in specific cases, and
+ // might not be available / required in all parsing contexts
+ data_rel_base: ?u64 = null,
+ text_rel_base: ?u64 = null,
+ function_rel_base: ?u64 = null,
+};
+fn readEhPointer(fbr: *FixedBufferReader, enc: u8, addr_size_bytes: u8, ctx: EhPointerContext) !?u64 {
+ if (enc == EH.PE.omit) return null;
+
+ const value: union(enum) {
+ signed: i64,
+ unsigned: u64,
+ } = switch (enc & EH.PE.type_mask) {
+ EH.PE.absptr => .{
+ .unsigned = switch (addr_size_bytes) {
+ 2 => try fbr.readInt(u16),
+ 4 => try fbr.readInt(u32),
+ 8 => try fbr.readInt(u64),
+ else => return error.InvalidAddrSize,
+ },
+ },
+ EH.PE.uleb128 => .{ .unsigned = try fbr.readUleb128(u64) },
+ EH.PE.udata2 => .{ .unsigned = try fbr.readInt(u16) },
+ EH.PE.udata4 => .{ .unsigned = try fbr.readInt(u32) },
+ EH.PE.udata8 => .{ .unsigned = try fbr.readInt(u64) },
+ EH.PE.sleb128 => .{ .signed = try fbr.readIleb128(i64) },
+ EH.PE.sdata2 => .{ .signed = try fbr.readInt(i16) },
+ EH.PE.sdata4 => .{ .signed = try fbr.readInt(i32) },
+ EH.PE.sdata8 => .{ .signed = try fbr.readInt(i64) },
+ else => return badDwarf(),
+ };
+
+ const base = switch (enc & EH.PE.rel_mask) {
+ EH.PE.pcrel => ctx.pc_rel_base,
+ EH.PE.textrel => ctx.text_rel_base orelse return error.PointerBaseNotSpecified,
+ EH.PE.datarel => ctx.data_rel_base orelse return error.PointerBaseNotSpecified,
+ EH.PE.funcrel => ctx.function_rel_base orelse return error.PointerBaseNotSpecified,
+ else => null,
+ };
+
+ const ptr: u64 = if (base) |b| switch (value) {
+ .signed => |s| @intCast(try std.math.add(i64, s, @as(i64, @intCast(b)))),
+ // absptr can actually contain signed values in some cases (aarch64 MachO)
+ .unsigned => |u| u +% b,
+ } else switch (value) {
+ .signed => |s| @as(u64, @intCast(s)),
+ .unsigned => |u| u,
+ };
+
+ if ((enc & EH.PE.indirect) > 0 and ctx.follow_indirect) {
+ if (@sizeOf(usize) != addr_size_bytes) {
+ // See the documentation for `follow_indirect`
+ return error.NonNativeIndirection;
+ }
+
+ const native_ptr = cast(usize, ptr) orelse return error.PointerOverflow;
+ return switch (addr_size_bytes) {
+ 2, 4, 8 => return @as(*const usize, @ptrFromInt(native_ptr)).*,
+ else => return error.UnsupportedAddrSize,
+ };
+ } else {
+ return ptr;
+ }
+}
+
+fn pcRelBase(field_ptr: usize, pc_rel_offset: i64) !usize {
+ if (pc_rel_offset < 0) {
+ return std.math.sub(usize, field_ptr, @as(usize, @intCast(-pc_rel_offset)));
+ } else {
+ return std.math.add(usize, field_ptr, @as(usize, @intCast(pc_rel_offset)));
+ }
+}
lib/std/debug.zig
@@ -18,6 +18,8 @@ const native_arch = builtin.cpu.arch;
const native_os = builtin.os.tag;
const native_endian = native_arch.endian();
+pub const Dwarf = @import("debug/Dwarf.zig");
+
pub const runtime_safety = switch (builtin.mode) {
.Debug, .ReleaseSafe => true,
.ReleaseFast, .ReleaseSmall => false,
@@ -67,7 +69,7 @@ pub const SymbolInfo = struct {
};
const PdbOrDwarf = union(enum) {
pdb: pdb.Pdb,
- dwarf: DW.DwarfInfo,
+ dwarf: Dwarf,
fn deinit(self: *PdbOrDwarf, allocator: mem.Allocator) void {
switch (self.*) {
@@ -566,7 +568,7 @@ pub const StackIterator = struct {
// using DWARF and MachO unwind info.
unwind_state: if (have_ucontext) ?struct {
debug_info: *Info,
- dwarf_context: DW.UnwindContext,
+ dwarf_context: Dwarf.UnwindContext,
last_error: ?UnwindError = null,
failed: bool = false,
} else void = if (have_ucontext) null else {},
@@ -599,7 +601,7 @@ pub const StackIterator = struct {
var iterator = init(first_address, null);
iterator.unwind_state = .{
.debug_info = debug_info,
- .dwarf_context = try DW.UnwindContext.init(debug_info.allocator, context),
+ .dwarf_context = try Dwarf.UnwindContext.init(debug_info.allocator, context),
};
return iterator;
@@ -783,7 +785,7 @@ pub const StackIterator = struct {
// __unwind_info is a requirement for unwinding on Darwin. It may fall back to DWARF, but unwinding
// via DWARF before attempting to use the compact unwind info will produce incorrect results.
if (module.unwind_info) |unwind_info| {
- if (DW.unwindFrameMachO(&unwind_state.dwarf_context, &it.ma, unwind_info, module.eh_frame, module.base_address)) |return_address| {
+ if (Dwarf.unwindFrameMachO(&unwind_state.dwarf_context, &it.ma, unwind_info, module.eh_frame, module.base_address)) |return_address| {
return return_address;
} else |err| {
if (err != error.RequiresDWARFUnwind) return err;
@@ -1140,10 +1142,10 @@ fn readCoffDebugInfo(allocator: mem.Allocator, coff_obj: *coff.Coff) !ModuleDebu
if (coff_obj.getSectionByName(".debug_info")) |_| {
// This coff file has embedded DWARF debug info
- var sections: DW.DwarfInfo.SectionArray = DW.DwarfInfo.null_section_array;
+ var sections: Dwarf.SectionArray = Dwarf.null_section_array;
errdefer for (sections) |section| if (section) |s| if (s.owned) allocator.free(s.data);
- inline for (@typeInfo(DW.DwarfSection).Enum.fields, 0..) |section, i| {
+ inline for (@typeInfo(Dwarf.Section.Id).Enum.fields, 0..) |section, i| {
sections[i] = if (coff_obj.getSectionByName("." ++ section.name)) |section_header| blk: {
break :blk .{
.data = try coff_obj.getSectionDataAlloc(section_header, allocator),
@@ -1153,13 +1155,13 @@ fn readCoffDebugInfo(allocator: mem.Allocator, coff_obj: *coff.Coff) !ModuleDebu
} else null;
}
- var dwarf = DW.DwarfInfo{
+ var dwarf = Dwarf{
.endian = native_endian,
.sections = sections,
.is_macho = false,
};
- try DW.openDwarfDebugInfo(&dwarf, allocator);
+ try Dwarf.open(&dwarf, allocator);
di.dwarf = dwarf;
}
@@ -1211,7 +1213,7 @@ pub fn readElfDebugInfo(
elf_filename: ?[]const u8,
build_id: ?[]const u8,
expected_crc: ?u32,
- parent_sections: *DW.DwarfInfo.SectionArray,
+ parent_sections: *Dwarf.SectionArray,
parent_mapped_mem: ?[]align(mem.page_size) const u8,
) !ModuleDebugInfo {
nosuspend {
@@ -1245,7 +1247,7 @@ pub fn readElfDebugInfo(
@ptrCast(@alignCast(&mapped_mem[shoff])),
)[0..hdr.e_shnum];
- var sections: DW.DwarfInfo.SectionArray = DW.DwarfInfo.null_section_array;
+ var sections: Dwarf.SectionArray = Dwarf.null_section_array;
// Combine section list. This takes ownership over any owned sections from the parent scope.
for (parent_sections, §ions) |*parent, *section| {
@@ -1274,7 +1276,7 @@ pub fn readElfDebugInfo(
}
var section_index: ?usize = null;
- inline for (@typeInfo(DW.DwarfSection).Enum.fields, 0..) |section, i| {
+ inline for (@typeInfo(Dwarf.Section.Id).Enum.fields, 0..) |section, i| {
if (mem.eql(u8, "." ++ section.name, name)) section_index = i;
}
if (section_index == null) continue;
@@ -1308,10 +1310,10 @@ pub fn readElfDebugInfo(
}
const missing_debug_info =
- sections[@intFromEnum(DW.DwarfSection.debug_info)] == null or
- sections[@intFromEnum(DW.DwarfSection.debug_abbrev)] == null or
- sections[@intFromEnum(DW.DwarfSection.debug_str)] == null or
- sections[@intFromEnum(DW.DwarfSection.debug_line)] == null;
+ sections[@intFromEnum(Dwarf.Section.Id.debug_info)] == null or
+ sections[@intFromEnum(Dwarf.Section.Id.debug_abbrev)] == null or
+ sections[@intFromEnum(Dwarf.Section.Id.debug_str)] == null or
+ sections[@intFromEnum(Dwarf.Section.Id.debug_line)] == null;
// Attempt to load debug info from an external file
// See: https://sourceware.org/gdb/onlinedocs/gdb/Separate-Debug-Files.html
@@ -1379,13 +1381,13 @@ pub fn readElfDebugInfo(
return error.MissingDebugInfo;
}
- var di = DW.DwarfInfo{
+ var di = Dwarf{
.endian = endian,
.sections = sections,
.is_macho = false,
};
- try DW.openDwarfDebugInfo(&di, allocator);
+ try Dwarf.open(&di, allocator);
return ModuleDebugInfo{
.base_address = undefined,
@@ -2168,13 +2170,13 @@ pub const Info = struct {
const obj_di = try self.allocator.create(ModuleDebugInfo);
errdefer self.allocator.destroy(obj_di);
- var sections: DW.DwarfInfo.SectionArray = DW.DwarfInfo.null_section_array;
+ var sections: Dwarf.SectionArray = Dwarf.null_section_array;
if (ctx.gnu_eh_frame) |eh_frame_hdr| {
// This is a special case - pointer offsets inside .eh_frame_hdr
// are encoded relative to its base address, so we must use the
// version that is already memory mapped, and not the one that
// will be mapped separately from the ELF file.
- sections[@intFromEnum(DW.DwarfSection.eh_frame_hdr)] = .{
+ sections[@intFromEnum(Dwarf.Section.Id.eh_frame_hdr)] = .{
.data = eh_frame_hdr,
.owned = false,
};
@@ -2219,7 +2221,7 @@ pub const ModuleDebugInfo = switch (native_os) {
const OFileTable = std.StringHashMap(OFileInfo);
const OFileInfo = struct {
- di: DW.DwarfInfo,
+ di: Dwarf,
addr_table: std.StringHashMap(u64),
};
@@ -2278,8 +2280,8 @@ pub const ModuleDebugInfo = switch (native_os) {
addr_table.putAssumeCapacityNoClobber(sym_name, sym.n_value);
}
- var sections: DW.DwarfInfo.SectionArray = DW.DwarfInfo.null_section_array;
- if (self.eh_frame) |eh_frame| sections[@intFromEnum(DW.DwarfSection.eh_frame)] = .{
+ var sections: Dwarf.SectionArray = Dwarf.null_section_array;
+ if (self.eh_frame) |eh_frame| sections[@intFromEnum(Dwarf.Section.Id.eh_frame)] = .{
.data = eh_frame,
.owned = false,
};
@@ -2288,7 +2290,7 @@ pub const ModuleDebugInfo = switch (native_os) {
if (!std.mem.eql(u8, "__DWARF", sect.segName())) continue;
var section_index: ?usize = null;
- inline for (@typeInfo(DW.DwarfSection).Enum.fields, 0..) |section, i| {
+ inline for (@typeInfo(Dwarf.Section.Id).Enum.fields, 0..) |section, i| {
if (mem.eql(u8, "__" ++ section.name, sect.sectName())) section_index = i;
}
if (section_index == null) continue;
@@ -2302,19 +2304,19 @@ pub const ModuleDebugInfo = switch (native_os) {
}
const missing_debug_info =
- sections[@intFromEnum(DW.DwarfSection.debug_info)] == null or
- sections[@intFromEnum(DW.DwarfSection.debug_abbrev)] == null or
- sections[@intFromEnum(DW.DwarfSection.debug_str)] == null or
- sections[@intFromEnum(DW.DwarfSection.debug_line)] == null;
+ sections[@intFromEnum(Dwarf.Section.Id.debug_info)] == null or
+ sections[@intFromEnum(Dwarf.Section.Id.debug_abbrev)] == null or
+ sections[@intFromEnum(Dwarf.Section.Id.debug_str)] == null or
+ sections[@intFromEnum(Dwarf.Section.Id.debug_line)] == null;
if (missing_debug_info) return error.MissingDebugInfo;
- var di = DW.DwarfInfo{
+ var di = Dwarf{
.endian = .little,
.sections = sections,
.is_macho = true,
};
- try DW.openDwarfDebugInfo(&di, allocator);
+ try Dwarf.open(&di, allocator);
const info = OFileInfo{
.di = di,
.addr_table = addr_table,
@@ -2411,14 +2413,14 @@ pub const ModuleDebugInfo = switch (native_os) {
}
}
- pub fn getDwarfInfoForAddress(self: *@This(), allocator: mem.Allocator, address: usize) !?*const DW.DwarfInfo {
+ pub fn getDwarfInfoForAddress(self: *@This(), allocator: mem.Allocator, address: usize) !?*const Dwarf {
return if ((try self.getOFileInfoForAddress(allocator, address)).o_file_info) |o_file_info| &o_file_info.di else null;
}
},
.uefi, .windows => struct {
base_address: usize,
pdb: ?pdb.Pdb = null,
- dwarf: ?DW.DwarfInfo = null,
+ dwarf: ?Dwarf = null,
coff_image_base: u64,
/// Only used if pdb is non-null
@@ -2488,7 +2490,7 @@ pub const ModuleDebugInfo = switch (native_os) {
return SymbolInfo{};
}
- pub fn getDwarfInfoForAddress(self: *@This(), allocator: mem.Allocator, address: usize) !?*const DW.DwarfInfo {
+ pub fn getDwarfInfoForAddress(self: *@This(), allocator: mem.Allocator, address: usize) !?*const Dwarf {
_ = allocator;
_ = address;
@@ -2500,7 +2502,7 @@ pub const ModuleDebugInfo = switch (native_os) {
},
.linux, .netbsd, .freebsd, .dragonfly, .openbsd, .haiku, .solaris, .illumos => struct {
base_address: usize,
- dwarf: DW.DwarfInfo,
+ dwarf: Dwarf,
mapped_memory: []align(mem.page_size) const u8,
external_mapped_memory: ?[]align(mem.page_size) const u8,
@@ -2516,7 +2518,7 @@ pub const ModuleDebugInfo = switch (native_os) {
return getSymbolFromDwarf(allocator, relocated_address, &self.dwarf);
}
- pub fn getDwarfInfoForAddress(self: *@This(), allocator: mem.Allocator, address: usize) !?*const DW.DwarfInfo {
+ pub fn getDwarfInfoForAddress(self: *@This(), allocator: mem.Allocator, address: usize) !?*const Dwarf {
_ = allocator;
_ = address;
return &self.dwarf;
@@ -2535,17 +2537,17 @@ pub const ModuleDebugInfo = switch (native_os) {
return SymbolInfo{};
}
- pub fn getDwarfInfoForAddress(self: *@This(), allocator: mem.Allocator, address: usize) !?*const DW.DwarfInfo {
+ pub fn getDwarfInfoForAddress(self: *@This(), allocator: mem.Allocator, address: usize) !?*const Dwarf {
_ = self;
_ = allocator;
_ = address;
return null;
}
},
- else => DW.DwarfInfo,
+ else => Dwarf,
};
-fn getSymbolFromDwarf(allocator: mem.Allocator, address: u64, di: *DW.DwarfInfo) !SymbolInfo {
+fn getSymbolFromDwarf(allocator: mem.Allocator, address: u64, di: *Dwarf) !SymbolInfo {
if (nosuspend di.findCompileUnit(address)) |compile_unit| {
return SymbolInfo{
.symbol_name = nosuspend di.getSymbolName(address) orelse "???",
lib/std/dwarf.zig
@@ -1,12 +1,8 @@
//! DWARF debugging data format.
-
-const builtin = @import("builtin");
-const std = @import("std.zig");
-const debug = std.debug;
-const mem = std.mem;
-const math = std.math;
-const assert = debug.assert;
-const native_endian = builtin.cpu.arch.endian();
+//!
+//! This namespace contains unopinionated types and data definitions only. For
+//! an implementation of parsing and caching DWARF information, see
+//! `std.debug.Dwarf`.
pub const TAG = @import("dwarf/TAG.zig");
pub const AT = @import("dwarf/AT.zig");
@@ -15,9 +11,7 @@ pub const LANG = @import("dwarf/LANG.zig");
pub const FORM = @import("dwarf/FORM.zig");
pub const ATE = @import("dwarf/ATE.zig");
pub const EH = @import("dwarf/EH.zig");
-pub const abi = @import("dwarf/abi.zig");
-pub const call_frame = @import("dwarf/call_frame.zig");
-pub const expressions = @import("dwarf/expressions.zig");
+pub const Format = enum { @"32", @"64" };
pub const LLE = struct {
pub const end_of_list = 0x00;
@@ -151,2689 +145,3 @@ pub const CC = enum(u8) {
pub const lo_user = 0x40;
pub const hi_user = 0xff;
};
-
-pub const Format = enum { @"32", @"64" };
-
-const PcRange = struct {
- start: u64,
- end: u64,
-};
-
-const Func = struct {
- pc_range: ?PcRange,
- name: ?[]const u8,
-};
-
-pub const CompileUnit = struct {
- version: u16,
- format: Format,
- die: Die,
- pc_range: ?PcRange,
-
- str_offsets_base: usize,
- addr_base: usize,
- rnglists_base: usize,
- loclists_base: usize,
- frame_base: ?*const FormValue,
-};
-
-const Abbrev = struct {
- code: u64,
- tag_id: u64,
- has_children: bool,
- attrs: []Attr,
-
- fn deinit(abbrev: *Abbrev, allocator: mem.Allocator) void {
- allocator.free(abbrev.attrs);
- abbrev.* = undefined;
- }
-
- const Attr = struct {
- id: u64,
- form_id: u64,
- /// Only valid if form_id is .implicit_const
- payload: i64,
- };
-
- const Table = struct {
- // offset from .debug_abbrev
- offset: u64,
- abbrevs: []Abbrev,
-
- fn deinit(table: *Table, allocator: mem.Allocator) void {
- for (table.abbrevs) |*abbrev| {
- abbrev.deinit(allocator);
- }
- allocator.free(table.abbrevs);
- table.* = undefined;
- }
-
- fn get(table: *const Table, abbrev_code: u64) ?*const Abbrev {
- return for (table.abbrevs) |*abbrev| {
- if (abbrev.code == abbrev_code) break abbrev;
- } else null;
- }
- };
-};
-
-pub const FormValue = union(enum) {
- addr: u64,
- addrx: usize,
- block: []const u8,
- udata: u64,
- data16: *const [16]u8,
- sdata: i64,
- exprloc: []const u8,
- flag: bool,
- sec_offset: u64,
- ref: u64,
- ref_addr: u64,
- string: [:0]const u8,
- strp: u64,
- strx: usize,
- line_strp: u64,
- loclistx: u64,
- rnglistx: u64,
-
- fn getString(fv: FormValue, di: DwarfInfo) ![:0]const u8 {
- switch (fv) {
- .string => |s| return s,
- .strp => |off| return di.getString(off),
- .line_strp => |off| return di.getLineString(off),
- else => return badDwarf(),
- }
- }
-
- fn getUInt(fv: FormValue, comptime U: type) !U {
- return switch (fv) {
- inline .udata,
- .sdata,
- .sec_offset,
- => |c| math.cast(U, c) orelse badDwarf(),
- else => badDwarf(),
- };
- }
-};
-
-const Die = struct {
- tag_id: u64,
- has_children: bool,
- attrs: []Attr,
-
- const Attr = struct {
- id: u64,
- value: FormValue,
- };
-
- fn deinit(self: *Die, allocator: mem.Allocator) void {
- allocator.free(self.attrs);
- self.* = undefined;
- }
-
- fn getAttr(self: *const Die, id: u64) ?*const FormValue {
- for (self.attrs) |*attr| {
- if (attr.id == id) return &attr.value;
- }
- return null;
- }
-
- fn getAttrAddr(
- self: *const Die,
- di: *const DwarfInfo,
- id: u64,
- compile_unit: CompileUnit,
- ) error{ InvalidDebugInfo, MissingDebugInfo }!u64 {
- const form_value = self.getAttr(id) orelse return error.MissingDebugInfo;
- return switch (form_value.*) {
- .addr => |value| value,
- .addrx => |index| di.readDebugAddr(compile_unit, index),
- else => error.InvalidDebugInfo,
- };
- }
-
- fn getAttrSecOffset(self: *const Die, id: u64) !u64 {
- const form_value = self.getAttr(id) orelse return error.MissingDebugInfo;
- return form_value.getUInt(u64);
- }
-
- fn getAttrUnsignedLe(self: *const Die, id: u64) !u64 {
- const form_value = self.getAttr(id) orelse return error.MissingDebugInfo;
- return switch (form_value.*) {
- .Const => |value| value.asUnsignedLe(),
- else => error.InvalidDebugInfo,
- };
- }
-
- fn getAttrRef(self: *const Die, id: u64) !u64 {
- const form_value = self.getAttr(id) orelse return error.MissingDebugInfo;
- return switch (form_value.*) {
- .ref => |value| value,
- else => error.InvalidDebugInfo,
- };
- }
-
- pub fn getAttrString(
- self: *const Die,
- di: *DwarfInfo,
- id: u64,
- opt_str: ?[]const u8,
- compile_unit: CompileUnit,
- ) error{ InvalidDebugInfo, MissingDebugInfo }![]const u8 {
- const form_value = self.getAttr(id) orelse return error.MissingDebugInfo;
- switch (form_value.*) {
- .string => |value| return value,
- .strp => |offset| return di.getString(offset),
- .strx => |index| {
- const debug_str_offsets = di.section(.debug_str_offsets) orelse return badDwarf();
- if (compile_unit.str_offsets_base == 0) return badDwarf();
- switch (compile_unit.format) {
- .@"32" => {
- const byte_offset = compile_unit.str_offsets_base + 4 * index;
- if (byte_offset + 4 > debug_str_offsets.len) return badDwarf();
- const offset = mem.readInt(u32, debug_str_offsets[byte_offset..][0..4], di.endian);
- return getStringGeneric(opt_str, offset);
- },
- .@"64" => {
- const byte_offset = compile_unit.str_offsets_base + 8 * index;
- if (byte_offset + 8 > debug_str_offsets.len) return badDwarf();
- const offset = mem.readInt(u64, debug_str_offsets[byte_offset..][0..8], di.endian);
- return getStringGeneric(opt_str, offset);
- },
- }
- },
- .line_strp => |offset| return di.getLineString(offset),
- else => return badDwarf(),
- }
- }
-};
-
-const FileEntry = struct {
- path: []const u8,
- dir_index: u32 = 0,
- mtime: u64 = 0,
- size: u64 = 0,
- md5: [16]u8 = [1]u8{0} ** 16,
-};
-
-const LineNumberProgram = struct {
- address: u64,
- file: usize,
- line: i64,
- column: u64,
- version: u16,
- is_stmt: bool,
- basic_block: bool,
- end_sequence: bool,
-
- default_is_stmt: bool,
- target_address: u64,
- include_dirs: []const FileEntry,
-
- prev_valid: bool,
- prev_address: u64,
- prev_file: usize,
- prev_line: i64,
- prev_column: u64,
- prev_is_stmt: bool,
- prev_basic_block: bool,
- prev_end_sequence: bool,
-
- // Reset the state machine following the DWARF specification
- pub fn reset(self: *LineNumberProgram) void {
- self.address = 0;
- self.file = 1;
- self.line = 1;
- self.column = 0;
- self.is_stmt = self.default_is_stmt;
- self.basic_block = false;
- self.end_sequence = false;
- // Invalidate all the remaining fields
- self.prev_valid = false;
- self.prev_address = 0;
- self.prev_file = undefined;
- self.prev_line = undefined;
- self.prev_column = undefined;
- self.prev_is_stmt = undefined;
- self.prev_basic_block = undefined;
- self.prev_end_sequence = undefined;
- }
-
- pub fn init(
- is_stmt: bool,
- include_dirs: []const FileEntry,
- target_address: u64,
- version: u16,
- ) LineNumberProgram {
- return LineNumberProgram{
- .address = 0,
- .file = 1,
- .line = 1,
- .column = 0,
- .version = version,
- .is_stmt = is_stmt,
- .basic_block = false,
- .end_sequence = false,
- .include_dirs = include_dirs,
- .default_is_stmt = is_stmt,
- .target_address = target_address,
- .prev_valid = false,
- .prev_address = 0,
- .prev_file = undefined,
- .prev_line = undefined,
- .prev_column = undefined,
- .prev_is_stmt = undefined,
- .prev_basic_block = undefined,
- .prev_end_sequence = undefined,
- };
- }
-
- pub fn checkLineMatch(
- self: *LineNumberProgram,
- allocator: mem.Allocator,
- file_entries: []const FileEntry,
- ) !?debug.LineInfo {
- if (self.prev_valid and
- self.target_address >= self.prev_address and
- self.target_address < self.address)
- {
- const file_index = if (self.version >= 5) self.prev_file else i: {
- if (self.prev_file == 0) return missingDwarf();
- break :i self.prev_file - 1;
- };
-
- if (file_index >= file_entries.len) return badDwarf();
- const file_entry = &file_entries[file_index];
-
- if (file_entry.dir_index >= self.include_dirs.len) return badDwarf();
- const dir_name = self.include_dirs[file_entry.dir_index].path;
-
- const file_name = try std.fs.path.join(allocator, &[_][]const u8{
- dir_name, file_entry.path,
- });
-
- return debug.LineInfo{
- .line = if (self.prev_line >= 0) @as(u64, @intCast(self.prev_line)) else 0,
- .column = self.prev_column,
- .file_name = file_name,
- };
- }
-
- self.prev_valid = true;
- self.prev_address = self.address;
- self.prev_file = self.file;
- self.prev_line = self.line;
- self.prev_column = self.column;
- self.prev_is_stmt = self.is_stmt;
- self.prev_basic_block = self.basic_block;
- self.prev_end_sequence = self.end_sequence;
- return null;
- }
-};
-
-const UnitHeader = struct {
- format: Format,
- header_length: u4,
- unit_length: u64,
-};
-fn readUnitHeader(fbr: *FixedBufferReader, opt_ma: ?*debug.StackIterator.MemoryAccessor) !UnitHeader {
- return switch (try if (opt_ma) |ma| fbr.readIntChecked(u32, ma) else fbr.readInt(u32)) {
- 0...0xfffffff0 - 1 => |unit_length| .{
- .format = .@"32",
- .header_length = 4,
- .unit_length = unit_length,
- },
- 0xfffffff0...0xffffffff - 1 => badDwarf(),
- 0xffffffff => .{
- .format = .@"64",
- .header_length = 12,
- .unit_length = try if (opt_ma) |ma| fbr.readIntChecked(u64, ma) else fbr.readInt(u64),
- },
- };
-}
-
-fn parseFormValue(
- fbr: *FixedBufferReader,
- form_id: u64,
- format: Format,
- implicit_const: ?i64,
-) anyerror!FormValue {
- return switch (form_id) {
- FORM.addr => .{ .addr = try fbr.readAddress(switch (@bitSizeOf(usize)) {
- 32 => .@"32",
- 64 => .@"64",
- else => @compileError("unsupported @sizeOf(usize)"),
- }) },
- FORM.addrx1 => .{ .addrx = try fbr.readInt(u8) },
- FORM.addrx2 => .{ .addrx = try fbr.readInt(u16) },
- FORM.addrx3 => .{ .addrx = try fbr.readInt(u24) },
- FORM.addrx4 => .{ .addrx = try fbr.readInt(u32) },
- FORM.addrx => .{ .addrx = try fbr.readUleb128(usize) },
-
- FORM.block1,
- FORM.block2,
- FORM.block4,
- FORM.block,
- => .{ .block = try fbr.readBytes(switch (form_id) {
- FORM.block1 => try fbr.readInt(u8),
- FORM.block2 => try fbr.readInt(u16),
- FORM.block4 => try fbr.readInt(u32),
- FORM.block => try fbr.readUleb128(usize),
- else => unreachable,
- }) },
-
- FORM.data1 => .{ .udata = try fbr.readInt(u8) },
- FORM.data2 => .{ .udata = try fbr.readInt(u16) },
- FORM.data4 => .{ .udata = try fbr.readInt(u32) },
- FORM.data8 => .{ .udata = try fbr.readInt(u64) },
- FORM.data16 => .{ .data16 = (try fbr.readBytes(16))[0..16] },
- FORM.udata => .{ .udata = try fbr.readUleb128(u64) },
- FORM.sdata => .{ .sdata = try fbr.readIleb128(i64) },
- FORM.exprloc => .{ .exprloc = try fbr.readBytes(try fbr.readUleb128(usize)) },
- FORM.flag => .{ .flag = (try fbr.readByte()) != 0 },
- FORM.flag_present => .{ .flag = true },
- FORM.sec_offset => .{ .sec_offset = try fbr.readAddress(format) },
-
- FORM.ref1 => .{ .ref = try fbr.readInt(u8) },
- FORM.ref2 => .{ .ref = try fbr.readInt(u16) },
- FORM.ref4 => .{ .ref = try fbr.readInt(u32) },
- FORM.ref8 => .{ .ref = try fbr.readInt(u64) },
- FORM.ref_udata => .{ .ref = try fbr.readUleb128(u64) },
-
- FORM.ref_addr => .{ .ref_addr = try fbr.readAddress(format) },
- FORM.ref_sig8 => .{ .ref = try fbr.readInt(u64) },
-
- FORM.string => .{ .string = try fbr.readBytesTo(0) },
- FORM.strp => .{ .strp = try fbr.readAddress(format) },
- FORM.strx1 => .{ .strx = try fbr.readInt(u8) },
- FORM.strx2 => .{ .strx = try fbr.readInt(u16) },
- FORM.strx3 => .{ .strx = try fbr.readInt(u24) },
- FORM.strx4 => .{ .strx = try fbr.readInt(u32) },
- FORM.strx => .{ .strx = try fbr.readUleb128(usize) },
- FORM.line_strp => .{ .line_strp = try fbr.readAddress(format) },
- FORM.indirect => parseFormValue(fbr, try fbr.readUleb128(u64), format, implicit_const),
- FORM.implicit_const => .{ .sdata = implicit_const orelse return badDwarf() },
- FORM.loclistx => .{ .loclistx = try fbr.readUleb128(u64) },
- FORM.rnglistx => .{ .rnglistx = try fbr.readUleb128(u64) },
- else => {
- //debug.print("unrecognized form id: {x}\n", .{form_id});
- return badDwarf();
- },
- };
-}
-
-pub const DwarfSection = enum {
- debug_info,
- debug_abbrev,
- debug_str,
- debug_str_offsets,
- debug_line,
- debug_line_str,
- debug_ranges,
- debug_loclists,
- debug_rnglists,
- debug_addr,
- debug_names,
- debug_frame,
- eh_frame,
- eh_frame_hdr,
-};
-
-pub const DwarfInfo = struct {
- pub const Section = struct {
- data: []const u8,
- // Module-relative virtual address.
- // Only set if the section data was loaded from disk.
- virtual_address: ?usize = null,
- // If `data` is owned by this DwarfInfo.
- owned: bool,
-
- // For sections that are not memory mapped by the loader, this is an offset
- // from `data.ptr` to where the section would have been mapped. Otherwise,
- // `data` is directly backed by the section and the offset is zero.
- pub fn virtualOffset(self: Section, base_address: usize) i64 {
- return if (self.virtual_address) |va|
- @as(i64, @intCast(base_address + va)) -
- @as(i64, @intCast(@intFromPtr(self.data.ptr)))
- else
- 0;
- }
- };
-
- const num_sections = std.enums.directEnumArrayLen(DwarfSection, 0);
- pub const SectionArray = [num_sections]?Section;
- pub const null_section_array = [_]?Section{null} ** num_sections;
-
- endian: std.builtin.Endian,
- sections: SectionArray = null_section_array,
- is_macho: bool,
-
- // Filled later by the initializer
- abbrev_table_list: std.ArrayListUnmanaged(Abbrev.Table) = .{},
- compile_unit_list: std.ArrayListUnmanaged(CompileUnit) = .{},
- func_list: std.ArrayListUnmanaged(Func) = .{},
-
- eh_frame_hdr: ?ExceptionFrameHeader = null,
- // These lookup tables are only used if `eh_frame_hdr` is null
- cie_map: std.AutoArrayHashMapUnmanaged(u64, CommonInformationEntry) = .{},
- // Sorted by start_pc
- fde_list: std.ArrayListUnmanaged(FrameDescriptionEntry) = .{},
-
- pub fn section(di: DwarfInfo, dwarf_section: DwarfSection) ?[]const u8 {
- return if (di.sections[@intFromEnum(dwarf_section)]) |s| s.data else null;
- }
-
- pub fn sectionVirtualOffset(di: DwarfInfo, dwarf_section: DwarfSection, base_address: usize) ?i64 {
- return if (di.sections[@intFromEnum(dwarf_section)]) |s| s.virtualOffset(base_address) else null;
- }
-
- pub fn deinit(di: *DwarfInfo, allocator: mem.Allocator) void {
- for (di.sections) |opt_section| {
- if (opt_section) |s| if (s.owned) allocator.free(s.data);
- }
- for (di.abbrev_table_list.items) |*abbrev| {
- abbrev.deinit(allocator);
- }
- di.abbrev_table_list.deinit(allocator);
- for (di.compile_unit_list.items) |*cu| {
- cu.die.deinit(allocator);
- }
- di.compile_unit_list.deinit(allocator);
- di.func_list.deinit(allocator);
- di.cie_map.deinit(allocator);
- di.fde_list.deinit(allocator);
- di.* = undefined;
- }
-
- pub fn getSymbolName(di: *DwarfInfo, address: u64) ?[]const u8 {
- for (di.func_list.items) |*func| {
- if (func.pc_range) |range| {
- if (address >= range.start and address < range.end) {
- return func.name;
- }
- }
- }
-
- return null;
- }
-
- fn scanAllFunctions(di: *DwarfInfo, allocator: mem.Allocator) !void {
- var fbr: FixedBufferReader = .{ .buf = di.section(.debug_info).?, .endian = di.endian };
- var this_unit_offset: u64 = 0;
-
- while (this_unit_offset < fbr.buf.len) {
- try fbr.seekTo(this_unit_offset);
-
- const unit_header = try readUnitHeader(&fbr, null);
- if (unit_header.unit_length == 0) return;
- const next_offset = unit_header.header_length + unit_header.unit_length;
-
- const version = try fbr.readInt(u16);
- if (version < 2 or version > 5) return badDwarf();
-
- var address_size: u8 = undefined;
- var debug_abbrev_offset: u64 = undefined;
- if (version >= 5) {
- const unit_type = try fbr.readInt(u8);
- if (unit_type != UT.compile) return badDwarf();
- address_size = try fbr.readByte();
- debug_abbrev_offset = try fbr.readAddress(unit_header.format);
- } else {
- debug_abbrev_offset = try fbr.readAddress(unit_header.format);
- address_size = try fbr.readByte();
- }
- if (address_size != @sizeOf(usize)) return badDwarf();
-
- const abbrev_table = try di.getAbbrevTable(allocator, debug_abbrev_offset);
-
- var max_attrs: usize = 0;
- var zig_padding_abbrev_code: u7 = 0;
- for (abbrev_table.abbrevs) |abbrev| {
- max_attrs = @max(max_attrs, abbrev.attrs.len);
- if (math.cast(u7, abbrev.code)) |code| {
- if (abbrev.tag_id == TAG.ZIG_padding and
- !abbrev.has_children and
- abbrev.attrs.len == 0)
- {
- zig_padding_abbrev_code = code;
- }
- }
- }
- const attrs_buf = try allocator.alloc(Die.Attr, max_attrs * 3);
- defer allocator.free(attrs_buf);
- var attrs_bufs: [3][]Die.Attr = undefined;
- for (&attrs_bufs, 0..) |*buf, index| buf.* = attrs_buf[index * max_attrs ..][0..max_attrs];
-
- const next_unit_pos = this_unit_offset + next_offset;
-
- var compile_unit: CompileUnit = .{
- .version = version,
- .format = unit_header.format,
- .die = undefined,
- .pc_range = null,
-
- .str_offsets_base = 0,
- .addr_base = 0,
- .rnglists_base = 0,
- .loclists_base = 0,
- .frame_base = null,
- };
-
- while (true) {
- fbr.pos = mem.indexOfNonePos(u8, fbr.buf, fbr.pos, &.{
- zig_padding_abbrev_code, 0,
- }) orelse fbr.buf.len;
- if (fbr.pos >= next_unit_pos) break;
- var die_obj = (try parseDie(
- &fbr,
- attrs_bufs[0],
- abbrev_table,
- unit_header.format,
- )) orelse continue;
-
- switch (die_obj.tag_id) {
- TAG.compile_unit => {
- compile_unit.die = die_obj;
- compile_unit.die.attrs = attrs_bufs[1][0..die_obj.attrs.len];
- @memcpy(compile_unit.die.attrs, die_obj.attrs);
-
- compile_unit.str_offsets_base = if (die_obj.getAttr(AT.str_offsets_base)) |fv| try fv.getUInt(usize) else 0;
- compile_unit.addr_base = if (die_obj.getAttr(AT.addr_base)) |fv| try fv.getUInt(usize) else 0;
- compile_unit.rnglists_base = if (die_obj.getAttr(AT.rnglists_base)) |fv| try fv.getUInt(usize) else 0;
- compile_unit.loclists_base = if (die_obj.getAttr(AT.loclists_base)) |fv| try fv.getUInt(usize) else 0;
- compile_unit.frame_base = die_obj.getAttr(AT.frame_base);
- },
- TAG.subprogram, TAG.inlined_subroutine, TAG.subroutine, TAG.entry_point => {
- const fn_name = x: {
- var this_die_obj = die_obj;
- // Prevent endless loops
- for (0..3) |_| {
- if (this_die_obj.getAttr(AT.name)) |_| {
- break :x try this_die_obj.getAttrString(di, AT.name, di.section(.debug_str), compile_unit);
- } else if (this_die_obj.getAttr(AT.abstract_origin)) |_| {
- const after_die_offset = fbr.pos;
- defer fbr.pos = after_die_offset;
-
- // Follow the DIE it points to and repeat
- const ref_offset = try this_die_obj.getAttrRef(AT.abstract_origin);
- if (ref_offset > next_offset) return badDwarf();
- try fbr.seekTo(this_unit_offset + ref_offset);
- this_die_obj = (try parseDie(
- &fbr,
- attrs_bufs[2],
- abbrev_table,
- unit_header.format,
- )) orelse return badDwarf();
- } else if (this_die_obj.getAttr(AT.specification)) |_| {
- const after_die_offset = fbr.pos;
- defer fbr.pos = after_die_offset;
-
- // Follow the DIE it points to and repeat
- const ref_offset = try this_die_obj.getAttrRef(AT.specification);
- if (ref_offset > next_offset) return badDwarf();
- try fbr.seekTo(this_unit_offset + ref_offset);
- this_die_obj = (try parseDie(
- &fbr,
- attrs_bufs[2],
- abbrev_table,
- unit_header.format,
- )) orelse return badDwarf();
- } else {
- break :x null;
- }
- }
-
- break :x null;
- };
-
- var range_added = if (die_obj.getAttrAddr(di, AT.low_pc, compile_unit)) |low_pc| blk: {
- if (die_obj.getAttr(AT.high_pc)) |high_pc_value| {
- const pc_end = switch (high_pc_value.*) {
- .addr => |value| value,
- .udata => |offset| low_pc + offset,
- else => return badDwarf(),
- };
-
- try di.func_list.append(allocator, .{
- .name = fn_name,
- .pc_range = .{
- .start = low_pc,
- .end = pc_end,
- },
- });
-
- break :blk true;
- }
-
- break :blk false;
- } else |err| blk: {
- if (err != error.MissingDebugInfo) return err;
- break :blk false;
- };
-
- if (die_obj.getAttr(AT.ranges)) |ranges_value| blk: {
- var iter = DebugRangeIterator.init(ranges_value, di, &compile_unit) catch |err| {
- if (err != error.MissingDebugInfo) return err;
- break :blk;
- };
-
- while (try iter.next()) |range| {
- range_added = true;
- try di.func_list.append(allocator, .{
- .name = fn_name,
- .pc_range = .{
- .start = range.start_addr,
- .end = range.end_addr,
- },
- });
- }
- }
-
- if (fn_name != null and !range_added) {
- try di.func_list.append(allocator, .{
- .name = fn_name,
- .pc_range = null,
- });
- }
- },
- else => {},
- }
- }
-
- this_unit_offset += next_offset;
- }
- }
-
- fn scanAllCompileUnits(di: *DwarfInfo, allocator: mem.Allocator) !void {
- var fbr: FixedBufferReader = .{ .buf = di.section(.debug_info).?, .endian = di.endian };
- var this_unit_offset: u64 = 0;
-
- var attrs_buf = std.ArrayList(Die.Attr).init(allocator);
- defer attrs_buf.deinit();
-
- while (this_unit_offset < fbr.buf.len) {
- try fbr.seekTo(this_unit_offset);
-
- const unit_header = try readUnitHeader(&fbr, null);
- if (unit_header.unit_length == 0) return;
- const next_offset = unit_header.header_length + unit_header.unit_length;
-
- const version = try fbr.readInt(u16);
- if (version < 2 or version > 5) return badDwarf();
-
- var address_size: u8 = undefined;
- var debug_abbrev_offset: u64 = undefined;
- if (version >= 5) {
- const unit_type = try fbr.readInt(u8);
- if (unit_type != UT.compile) return badDwarf();
- address_size = try fbr.readByte();
- debug_abbrev_offset = try fbr.readAddress(unit_header.format);
- } else {
- debug_abbrev_offset = try fbr.readAddress(unit_header.format);
- address_size = try fbr.readByte();
- }
- if (address_size != @sizeOf(usize)) return badDwarf();
-
- const abbrev_table = try di.getAbbrevTable(allocator, debug_abbrev_offset);
-
- var max_attrs: usize = 0;
- for (abbrev_table.abbrevs) |abbrev| {
- max_attrs = @max(max_attrs, abbrev.attrs.len);
- }
- try attrs_buf.resize(max_attrs);
-
- var compile_unit_die = (try parseDie(
- &fbr,
- attrs_buf.items,
- abbrev_table,
- unit_header.format,
- )) orelse return badDwarf();
-
- if (compile_unit_die.tag_id != TAG.compile_unit) return badDwarf();
-
- compile_unit_die.attrs = try allocator.dupe(Die.Attr, compile_unit_die.attrs);
-
- var compile_unit: CompileUnit = .{
- .version = version,
- .format = unit_header.format,
- .pc_range = null,
- .die = compile_unit_die,
- .str_offsets_base = if (compile_unit_die.getAttr(AT.str_offsets_base)) |fv| try fv.getUInt(usize) else 0,
- .addr_base = if (compile_unit_die.getAttr(AT.addr_base)) |fv| try fv.getUInt(usize) else 0,
- .rnglists_base = if (compile_unit_die.getAttr(AT.rnglists_base)) |fv| try fv.getUInt(usize) else 0,
- .loclists_base = if (compile_unit_die.getAttr(AT.loclists_base)) |fv| try fv.getUInt(usize) else 0,
- .frame_base = compile_unit_die.getAttr(AT.frame_base),
- };
-
- compile_unit.pc_range = x: {
- if (compile_unit_die.getAttrAddr(di, AT.low_pc, compile_unit)) |low_pc| {
- if (compile_unit_die.getAttr(AT.high_pc)) |high_pc_value| {
- const pc_end = switch (high_pc_value.*) {
- .addr => |value| value,
- .udata => |offset| low_pc + offset,
- else => return badDwarf(),
- };
- break :x PcRange{
- .start = low_pc,
- .end = pc_end,
- };
- } else {
- break :x null;
- }
- } else |err| {
- if (err != error.MissingDebugInfo) return err;
- break :x null;
- }
- };
-
- try di.compile_unit_list.append(allocator, compile_unit);
-
- this_unit_offset += next_offset;
- }
- }
-
- const DebugRangeIterator = struct {
- base_address: u64,
- section_type: DwarfSection,
- di: *const DwarfInfo,
- compile_unit: *const CompileUnit,
- fbr: FixedBufferReader,
-
- pub fn init(ranges_value: *const FormValue, di: *const DwarfInfo, compile_unit: *const CompileUnit) !@This() {
- const section_type = if (compile_unit.version >= 5) DwarfSection.debug_rnglists else DwarfSection.debug_ranges;
- const debug_ranges = di.section(section_type) orelse return error.MissingDebugInfo;
-
- const ranges_offset = switch (ranges_value.*) {
- .sec_offset, .udata => |off| off,
- .rnglistx => |idx| off: {
- switch (compile_unit.format) {
- .@"32" => {
- const offset_loc = @as(usize, @intCast(compile_unit.rnglists_base + 4 * idx));
- if (offset_loc + 4 > debug_ranges.len) return badDwarf();
- const offset = mem.readInt(u32, debug_ranges[offset_loc..][0..4], di.endian);
- break :off compile_unit.rnglists_base + offset;
- },
- .@"64" => {
- const offset_loc = @as(usize, @intCast(compile_unit.rnglists_base + 8 * idx));
- if (offset_loc + 8 > debug_ranges.len) return badDwarf();
- const offset = mem.readInt(u64, debug_ranges[offset_loc..][0..8], di.endian);
- break :off compile_unit.rnglists_base + offset;
- },
- }
- },
- else => return badDwarf(),
- };
-
- // All the addresses in the list are relative to the value
- // specified by DW_AT.low_pc or to some other value encoded
- // in the list itself.
- // If no starting value is specified use zero.
- const base_address = compile_unit.die.getAttrAddr(di, AT.low_pc, compile_unit.*) catch |err| switch (err) {
- error.MissingDebugInfo => 0,
- else => return err,
- };
-
- return .{
- .base_address = base_address,
- .section_type = section_type,
- .di = di,
- .compile_unit = compile_unit,
- .fbr = .{
- .buf = debug_ranges,
- .pos = math.cast(usize, ranges_offset) orelse return badDwarf(),
- .endian = di.endian,
- },
- };
- }
-
- // Returns the next range in the list, or null if the end was reached.
- pub fn next(self: *@This()) !?struct { start_addr: u64, end_addr: u64 } {
- switch (self.section_type) {
- .debug_rnglists => {
- const kind = try self.fbr.readByte();
- switch (kind) {
- RLE.end_of_list => return null,
- RLE.base_addressx => {
- const index = try self.fbr.readUleb128(usize);
- self.base_address = try self.di.readDebugAddr(self.compile_unit.*, index);
- return try self.next();
- },
- RLE.startx_endx => {
- const start_index = try self.fbr.readUleb128(usize);
- const start_addr = try self.di.readDebugAddr(self.compile_unit.*, start_index);
-
- const end_index = try self.fbr.readUleb128(usize);
- const end_addr = try self.di.readDebugAddr(self.compile_unit.*, end_index);
-
- return .{
- .start_addr = start_addr,
- .end_addr = end_addr,
- };
- },
- RLE.startx_length => {
- const start_index = try self.fbr.readUleb128(usize);
- const start_addr = try self.di.readDebugAddr(self.compile_unit.*, start_index);
-
- const len = try self.fbr.readUleb128(usize);
- const end_addr = start_addr + len;
-
- return .{
- .start_addr = start_addr,
- .end_addr = end_addr,
- };
- },
- RLE.offset_pair => {
- const start_addr = try self.fbr.readUleb128(usize);
- const end_addr = try self.fbr.readUleb128(usize);
-
- // This is the only kind that uses the base address
- return .{
- .start_addr = self.base_address + start_addr,
- .end_addr = self.base_address + end_addr,
- };
- },
- RLE.base_address => {
- self.base_address = try self.fbr.readInt(usize);
- return try self.next();
- },
- RLE.start_end => {
- const start_addr = try self.fbr.readInt(usize);
- const end_addr = try self.fbr.readInt(usize);
-
- return .{
- .start_addr = start_addr,
- .end_addr = end_addr,
- };
- },
- RLE.start_length => {
- const start_addr = try self.fbr.readInt(usize);
- const len = try self.fbr.readUleb128(usize);
- const end_addr = start_addr + len;
-
- return .{
- .start_addr = start_addr,
- .end_addr = end_addr,
- };
- },
- else => return badDwarf(),
- }
- },
- .debug_ranges => {
- const start_addr = try self.fbr.readInt(usize);
- const end_addr = try self.fbr.readInt(usize);
- if (start_addr == 0 and end_addr == 0) return null;
-
- // This entry selects a new value for the base address
- if (start_addr == math.maxInt(usize)) {
- self.base_address = end_addr;
- return try self.next();
- }
-
- return .{
- .start_addr = self.base_address + start_addr,
- .end_addr = self.base_address + end_addr,
- };
- },
- else => unreachable,
- }
- }
- };
-
- pub fn findCompileUnit(di: *const DwarfInfo, target_address: u64) !*const CompileUnit {
- for (di.compile_unit_list.items) |*compile_unit| {
- if (compile_unit.pc_range) |range| {
- if (target_address >= range.start and target_address < range.end) return compile_unit;
- }
-
- const ranges_value = compile_unit.die.getAttr(AT.ranges) orelse continue;
- var iter = DebugRangeIterator.init(ranges_value, di, compile_unit) catch continue;
- while (try iter.next()) |range| {
- if (target_address >= range.start_addr and target_address < range.end_addr) return compile_unit;
- }
- }
-
- return missingDwarf();
- }
-
- /// Gets an already existing AbbrevTable given the abbrev_offset, or if not found,
- /// seeks in the stream and parses it.
- fn getAbbrevTable(di: *DwarfInfo, allocator: mem.Allocator, abbrev_offset: u64) !*const Abbrev.Table {
- for (di.abbrev_table_list.items) |*table| {
- if (table.offset == abbrev_offset) {
- return table;
- }
- }
- try di.abbrev_table_list.append(
- allocator,
- try di.parseAbbrevTable(allocator, abbrev_offset),
- );
- return &di.abbrev_table_list.items[di.abbrev_table_list.items.len - 1];
- }
-
- fn parseAbbrevTable(di: *DwarfInfo, allocator: mem.Allocator, offset: u64) !Abbrev.Table {
- var fbr: FixedBufferReader = .{
- .buf = di.section(.debug_abbrev).?,
- .pos = math.cast(usize, offset) orelse return badDwarf(),
- .endian = di.endian,
- };
-
- var abbrevs = std.ArrayList(Abbrev).init(allocator);
- defer {
- for (abbrevs.items) |*abbrev| {
- abbrev.deinit(allocator);
- }
- abbrevs.deinit();
- }
-
- var attrs = std.ArrayList(Abbrev.Attr).init(allocator);
- defer attrs.deinit();
-
- while (true) {
- const code = try fbr.readUleb128(u64);
- if (code == 0) break;
- const tag_id = try fbr.readUleb128(u64);
- const has_children = (try fbr.readByte()) == CHILDREN.yes;
-
- while (true) {
- const attr_id = try fbr.readUleb128(u64);
- const form_id = try fbr.readUleb128(u64);
- if (attr_id == 0 and form_id == 0) break;
- try attrs.append(.{
- .id = attr_id,
- .form_id = form_id,
- .payload = switch (form_id) {
- FORM.implicit_const => try fbr.readIleb128(i64),
- else => undefined,
- },
- });
- }
-
- try abbrevs.append(.{
- .code = code,
- .tag_id = tag_id,
- .has_children = has_children,
- .attrs = try attrs.toOwnedSlice(),
- });
- }
-
- return .{
- .offset = offset,
- .abbrevs = try abbrevs.toOwnedSlice(),
- };
- }
-
- fn parseDie(
- fbr: *FixedBufferReader,
- attrs_buf: []Die.Attr,
- abbrev_table: *const Abbrev.Table,
- format: Format,
- ) !?Die {
- const abbrev_code = try fbr.readUleb128(u64);
- if (abbrev_code == 0) return null;
- const table_entry = abbrev_table.get(abbrev_code) orelse return badDwarf();
-
- const attrs = attrs_buf[0..table_entry.attrs.len];
- for (attrs, table_entry.attrs) |*result_attr, attr| result_attr.* = Die.Attr{
- .id = attr.id,
- .value = try parseFormValue(
- fbr,
- attr.form_id,
- format,
- attr.payload,
- ),
- };
- return .{
- .tag_id = table_entry.tag_id,
- .has_children = table_entry.has_children,
- .attrs = attrs,
- };
- }
-
- pub fn getLineNumberInfo(
- di: *DwarfInfo,
- allocator: mem.Allocator,
- compile_unit: CompileUnit,
- target_address: u64,
- ) !debug.LineInfo {
- const compile_unit_cwd = try compile_unit.die.getAttrString(di, AT.comp_dir, di.section(.debug_line_str), compile_unit);
- const line_info_offset = try compile_unit.die.getAttrSecOffset(AT.stmt_list);
-
- var fbr: FixedBufferReader = .{ .buf = di.section(.debug_line).?, .endian = di.endian };
- try fbr.seekTo(line_info_offset);
-
- const unit_header = try readUnitHeader(&fbr, null);
- if (unit_header.unit_length == 0) return missingDwarf();
- const next_offset = unit_header.header_length + unit_header.unit_length;
-
- const version = try fbr.readInt(u16);
- if (version < 2) return badDwarf();
-
- var addr_size: u8 = switch (unit_header.format) {
- .@"32" => 4,
- .@"64" => 8,
- };
- var seg_size: u8 = 0;
- if (version >= 5) {
- addr_size = try fbr.readByte();
- seg_size = try fbr.readByte();
- }
-
- const prologue_length = try fbr.readAddress(unit_header.format);
- const prog_start_offset = fbr.pos + prologue_length;
-
- const minimum_instruction_length = try fbr.readByte();
- if (minimum_instruction_length == 0) return badDwarf();
-
- if (version >= 4) {
- // maximum_operations_per_instruction
- _ = try fbr.readByte();
- }
-
- const default_is_stmt = (try fbr.readByte()) != 0;
- const line_base = try fbr.readByteSigned();
-
- const line_range = try fbr.readByte();
- if (line_range == 0) return badDwarf();
-
- const opcode_base = try fbr.readByte();
-
- const standard_opcode_lengths = try fbr.readBytes(opcode_base - 1);
-
- var include_directories = std.ArrayList(FileEntry).init(allocator);
- defer include_directories.deinit();
- var file_entries = std.ArrayList(FileEntry).init(allocator);
- defer file_entries.deinit();
-
- if (version < 5) {
- try include_directories.append(.{ .path = compile_unit_cwd });
-
- while (true) {
- const dir = try fbr.readBytesTo(0);
- if (dir.len == 0) break;
- try include_directories.append(.{ .path = dir });
- }
-
- while (true) {
- const file_name = try fbr.readBytesTo(0);
- if (file_name.len == 0) break;
- const dir_index = try fbr.readUleb128(u32);
- const mtime = try fbr.readUleb128(u64);
- const size = try fbr.readUleb128(u64);
- try file_entries.append(.{
- .path = file_name,
- .dir_index = dir_index,
- .mtime = mtime,
- .size = size,
- });
- }
- } else {
- const FileEntFmt = struct {
- content_type_code: u8,
- form_code: u16,
- };
- {
- var dir_ent_fmt_buf: [10]FileEntFmt = undefined;
- const directory_entry_format_count = try fbr.readByte();
- if (directory_entry_format_count > dir_ent_fmt_buf.len) return badDwarf();
- for (dir_ent_fmt_buf[0..directory_entry_format_count]) |*ent_fmt| {
- ent_fmt.* = .{
- .content_type_code = try fbr.readUleb128(u8),
- .form_code = try fbr.readUleb128(u16),
- };
- }
-
- const directories_count = try fbr.readUleb128(usize);
- try include_directories.ensureUnusedCapacity(directories_count);
- {
- var i: usize = 0;
- while (i < directories_count) : (i += 1) {
- var e: FileEntry = .{ .path = &.{} };
- for (dir_ent_fmt_buf[0..directory_entry_format_count]) |ent_fmt| {
- const form_value = try parseFormValue(
- &fbr,
- ent_fmt.form_code,
- unit_header.format,
- null,
- );
- switch (ent_fmt.content_type_code) {
- LNCT.path => e.path = try form_value.getString(di.*),
- LNCT.directory_index => e.dir_index = try form_value.getUInt(u32),
- LNCT.timestamp => e.mtime = try form_value.getUInt(u64),
- LNCT.size => e.size = try form_value.getUInt(u64),
- LNCT.MD5 => e.md5 = switch (form_value) {
- .data16 => |data16| data16.*,
- else => return badDwarf(),
- },
- else => continue,
- }
- }
- include_directories.appendAssumeCapacity(e);
- }
- }
- }
-
- var file_ent_fmt_buf: [10]FileEntFmt = undefined;
- const file_name_entry_format_count = try fbr.readByte();
- if (file_name_entry_format_count > file_ent_fmt_buf.len) return badDwarf();
- for (file_ent_fmt_buf[0..file_name_entry_format_count]) |*ent_fmt| {
- ent_fmt.* = .{
- .content_type_code = try fbr.readUleb128(u8),
- .form_code = try fbr.readUleb128(u16),
- };
- }
-
- const file_names_count = try fbr.readUleb128(usize);
- try file_entries.ensureUnusedCapacity(file_names_count);
- {
- var i: usize = 0;
- while (i < file_names_count) : (i += 1) {
- var e: FileEntry = .{ .path = &.{} };
- for (file_ent_fmt_buf[0..file_name_entry_format_count]) |ent_fmt| {
- const form_value = try parseFormValue(
- &fbr,
- ent_fmt.form_code,
- unit_header.format,
- null,
- );
- switch (ent_fmt.content_type_code) {
- LNCT.path => e.path = try form_value.getString(di.*),
- LNCT.directory_index => e.dir_index = try form_value.getUInt(u32),
- LNCT.timestamp => e.mtime = try form_value.getUInt(u64),
- LNCT.size => e.size = try form_value.getUInt(u64),
- LNCT.MD5 => e.md5 = switch (form_value) {
- .data16 => |data16| data16.*,
- else => return badDwarf(),
- },
- else => continue,
- }
- }
- file_entries.appendAssumeCapacity(e);
- }
- }
- }
-
- var prog = LineNumberProgram.init(
- default_is_stmt,
- include_directories.items,
- target_address,
- version,
- );
-
- try fbr.seekTo(prog_start_offset);
-
- const next_unit_pos = line_info_offset + next_offset;
-
- while (fbr.pos < next_unit_pos) {
- const opcode = try fbr.readByte();
-
- if (opcode == LNS.extended_op) {
- const op_size = try fbr.readUleb128(u64);
- if (op_size < 1) return badDwarf();
- const sub_op = try fbr.readByte();
- switch (sub_op) {
- LNE.end_sequence => {
- prog.end_sequence = true;
- if (try prog.checkLineMatch(allocator, file_entries.items)) |info| return info;
- prog.reset();
- },
- LNE.set_address => {
- const addr = try fbr.readInt(usize);
- prog.address = addr;
- },
- LNE.define_file => {
- const path = try fbr.readBytesTo(0);
- const dir_index = try fbr.readUleb128(u32);
- const mtime = try fbr.readUleb128(u64);
- const size = try fbr.readUleb128(u64);
- try file_entries.append(.{
- .path = path,
- .dir_index = dir_index,
- .mtime = mtime,
- .size = size,
- });
- },
- else => try fbr.seekForward(op_size - 1),
- }
- } else if (opcode >= opcode_base) {
- // special opcodes
- const adjusted_opcode = opcode - opcode_base;
- const inc_addr = minimum_instruction_length * (adjusted_opcode / line_range);
- const inc_line = @as(i32, line_base) + @as(i32, adjusted_opcode % line_range);
- prog.line += inc_line;
- prog.address += inc_addr;
- if (try prog.checkLineMatch(allocator, file_entries.items)) |info| return info;
- prog.basic_block = false;
- } else {
- switch (opcode) {
- LNS.copy => {
- if (try prog.checkLineMatch(allocator, file_entries.items)) |info| return info;
- prog.basic_block = false;
- },
- LNS.advance_pc => {
- const arg = try fbr.readUleb128(usize);
- prog.address += arg * minimum_instruction_length;
- },
- LNS.advance_line => {
- const arg = try fbr.readIleb128(i64);
- prog.line += arg;
- },
- LNS.set_file => {
- const arg = try fbr.readUleb128(usize);
- prog.file = arg;
- },
- LNS.set_column => {
- const arg = try fbr.readUleb128(u64);
- prog.column = arg;
- },
- LNS.negate_stmt => {
- prog.is_stmt = !prog.is_stmt;
- },
- LNS.set_basic_block => {
- prog.basic_block = true;
- },
- LNS.const_add_pc => {
- const inc_addr = minimum_instruction_length * ((255 - opcode_base) / line_range);
- prog.address += inc_addr;
- },
- LNS.fixed_advance_pc => {
- const arg = try fbr.readInt(u16);
- prog.address += arg;
- },
- LNS.set_prologue_end => {},
- else => {
- if (opcode - 1 >= standard_opcode_lengths.len) return badDwarf();
- try fbr.seekForward(standard_opcode_lengths[opcode - 1]);
- },
- }
- }
- }
-
- return missingDwarf();
- }
-
- fn getString(di: DwarfInfo, offset: u64) ![:0]const u8 {
- return getStringGeneric(di.section(.debug_str), offset);
- }
-
- fn getLineString(di: DwarfInfo, offset: u64) ![:0]const u8 {
- return getStringGeneric(di.section(.debug_line_str), offset);
- }
-
- fn readDebugAddr(di: DwarfInfo, compile_unit: CompileUnit, index: u64) !u64 {
- const debug_addr = di.section(.debug_addr) orelse return badDwarf();
-
- // addr_base points to the first item after the header, however we
- // need to read the header to know the size of each item. Empirically,
- // it may disagree with is_64 on the compile unit.
- // The header is 8 or 12 bytes depending on is_64.
- if (compile_unit.addr_base < 8) return badDwarf();
-
- const version = mem.readInt(u16, debug_addr[compile_unit.addr_base - 4 ..][0..2], di.endian);
- if (version != 5) return badDwarf();
-
- const addr_size = debug_addr[compile_unit.addr_base - 2];
- const seg_size = debug_addr[compile_unit.addr_base - 1];
-
- const byte_offset = @as(usize, @intCast(compile_unit.addr_base + (addr_size + seg_size) * index));
- if (byte_offset + addr_size > debug_addr.len) return badDwarf();
- return switch (addr_size) {
- 1 => debug_addr[byte_offset],
- 2 => mem.readInt(u16, debug_addr[byte_offset..][0..2], di.endian),
- 4 => mem.readInt(u32, debug_addr[byte_offset..][0..4], di.endian),
- 8 => mem.readInt(u64, debug_addr[byte_offset..][0..8], di.endian),
- else => badDwarf(),
- };
- }
-
- /// If .eh_frame_hdr is present, then only the header needs to be parsed.
- ///
- /// Otherwise, .eh_frame and .debug_frame are scanned and a sorted list
- /// of FDEs is built for binary searching during unwinding.
- pub fn scanAllUnwindInfo(di: *DwarfInfo, allocator: mem.Allocator, base_address: usize) !void {
- if (di.section(.eh_frame_hdr)) |eh_frame_hdr| blk: {
- var fbr: FixedBufferReader = .{ .buf = eh_frame_hdr, .endian = native_endian };
-
- const version = try fbr.readByte();
- if (version != 1) break :blk;
-
- const eh_frame_ptr_enc = try fbr.readByte();
- if (eh_frame_ptr_enc == EH.PE.omit) break :blk;
- const fde_count_enc = try fbr.readByte();
- if (fde_count_enc == EH.PE.omit) break :blk;
- const table_enc = try fbr.readByte();
- if (table_enc == EH.PE.omit) break :blk;
-
- const eh_frame_ptr = math.cast(usize, try readEhPointer(&fbr, eh_frame_ptr_enc, @sizeOf(usize), .{
- .pc_rel_base = @intFromPtr(&eh_frame_hdr[fbr.pos]),
- .follow_indirect = true,
- }) orelse return badDwarf()) orelse return badDwarf();
-
- const fde_count = math.cast(usize, try readEhPointer(&fbr, fde_count_enc, @sizeOf(usize), .{
- .pc_rel_base = @intFromPtr(&eh_frame_hdr[fbr.pos]),
- .follow_indirect = true,
- }) orelse return badDwarf()) orelse return badDwarf();
-
- const entry_size = try ExceptionFrameHeader.entrySize(table_enc);
- const entries_len = fde_count * entry_size;
- if (entries_len > eh_frame_hdr.len - fbr.pos) return badDwarf();
-
- di.eh_frame_hdr = .{
- .eh_frame_ptr = eh_frame_ptr,
- .table_enc = table_enc,
- .fde_count = fde_count,
- .entries = eh_frame_hdr[fbr.pos..][0..entries_len],
- };
-
- // No need to scan .eh_frame, we have a binary search table already
- return;
- }
-
- const frame_sections = [2]DwarfSection{ .eh_frame, .debug_frame };
- for (frame_sections) |frame_section| {
- if (di.section(frame_section)) |section_data| {
- var fbr: FixedBufferReader = .{ .buf = section_data, .endian = di.endian };
- while (fbr.pos < fbr.buf.len) {
- const entry_header = try EntryHeader.read(&fbr, null, frame_section);
- switch (entry_header.type) {
- .cie => {
- const cie = try CommonInformationEntry.parse(
- entry_header.entry_bytes,
- di.sectionVirtualOffset(frame_section, base_address).?,
- true,
- entry_header.format,
- frame_section,
- entry_header.length_offset,
- @sizeOf(usize),
- di.endian,
- );
- try di.cie_map.put(allocator, entry_header.length_offset, cie);
- },
- .fde => |cie_offset| {
- const cie = di.cie_map.get(cie_offset) orelse return badDwarf();
- const fde = try FrameDescriptionEntry.parse(
- entry_header.entry_bytes,
- di.sectionVirtualOffset(frame_section, base_address).?,
- true,
- cie,
- @sizeOf(usize),
- di.endian,
- );
- try di.fde_list.append(allocator, fde);
- },
- .terminator => break,
- }
- }
-
- mem.sortUnstable(FrameDescriptionEntry, di.fde_list.items, {}, struct {
- fn lessThan(ctx: void, a: FrameDescriptionEntry, b: FrameDescriptionEntry) bool {
- _ = ctx;
- return a.pc_begin < b.pc_begin;
- }
- }.lessThan);
- }
- }
- }
-
- /// Unwind a stack frame using DWARF unwinding info, updating the register context.
- ///
- /// If `.eh_frame_hdr` is available, it will be used to binary search for the FDE.
- /// Otherwise, a linear scan of `.eh_frame` and `.debug_frame` is done to find the FDE.
- ///
- /// `explicit_fde_offset` is for cases where the FDE offset is known, such as when __unwind_info
- /// defers unwinding to DWARF. This is an offset into the `.eh_frame` section.
- pub fn unwindFrame(di: *const DwarfInfo, context: *UnwindContext, ma: *debug.StackIterator.MemoryAccessor, explicit_fde_offset: ?usize) !usize {
- if (!comptime abi.supportsUnwinding(builtin.target)) return error.UnsupportedCpuArchitecture;
- if (context.pc == 0) return 0;
-
- // Find the FDE and CIE
- var cie: CommonInformationEntry = undefined;
- var fde: FrameDescriptionEntry = undefined;
-
- if (explicit_fde_offset) |fde_offset| {
- const dwarf_section: DwarfSection = .eh_frame;
- const frame_section = di.section(dwarf_section) orelse return error.MissingFDE;
- if (fde_offset >= frame_section.len) return error.MissingFDE;
-
- var fbr: FixedBufferReader = .{
- .buf = frame_section,
- .pos = fde_offset,
- .endian = di.endian,
- };
-
- const fde_entry_header = try EntryHeader.read(&fbr, null, dwarf_section);
- if (fde_entry_header.type != .fde) return error.MissingFDE;
-
- const cie_offset = fde_entry_header.type.fde;
- try fbr.seekTo(cie_offset);
-
- fbr.endian = native_endian;
- const cie_entry_header = try EntryHeader.read(&fbr, null, dwarf_section);
- if (cie_entry_header.type != .cie) return badDwarf();
-
- cie = try CommonInformationEntry.parse(
- cie_entry_header.entry_bytes,
- 0,
- true,
- cie_entry_header.format,
- dwarf_section,
- cie_entry_header.length_offset,
- @sizeOf(usize),
- native_endian,
- );
-
- fde = try FrameDescriptionEntry.parse(
- fde_entry_header.entry_bytes,
- 0,
- true,
- cie,
- @sizeOf(usize),
- native_endian,
- );
- } else if (di.eh_frame_hdr) |header| {
- const eh_frame_len = if (di.section(.eh_frame)) |eh_frame| eh_frame.len else null;
- try header.findEntry(
- ma,
- eh_frame_len,
- @intFromPtr(di.section(.eh_frame_hdr).?.ptr),
- context.pc,
- &cie,
- &fde,
- );
- } else {
- const index = std.sort.binarySearch(FrameDescriptionEntry, context.pc, di.fde_list.items, {}, struct {
- pub fn compareFn(_: void, pc: usize, mid_item: FrameDescriptionEntry) math.Order {
- if (pc < mid_item.pc_begin) return .lt;
-
- const range_end = mid_item.pc_begin + mid_item.pc_range;
- if (pc < range_end) return .eq;
-
- return .gt;
- }
- }.compareFn);
-
- fde = if (index) |i| di.fde_list.items[i] else return error.MissingFDE;
- cie = di.cie_map.get(fde.cie_length_offset) orelse return error.MissingCIE;
- }
-
- var expression_context: expressions.ExpressionContext = .{
- .format = cie.format,
- .memory_accessor = ma,
- .compile_unit = di.findCompileUnit(fde.pc_begin) catch null,
- .thread_context = context.thread_context,
- .reg_context = context.reg_context,
- .cfa = context.cfa,
- };
-
- context.vm.reset();
- context.reg_context.eh_frame = cie.version != 4;
- context.reg_context.is_macho = di.is_macho;
-
- const row = try context.vm.runToNative(context.allocator, context.pc, cie, fde);
- context.cfa = switch (row.cfa.rule) {
- .val_offset => |offset| blk: {
- const register = row.cfa.register orelse return error.InvalidCFARule;
- const value = mem.readInt(usize, (try abi.regBytes(context.thread_context, register, context.reg_context))[0..@sizeOf(usize)], native_endian);
- break :blk try call_frame.applyOffset(value, offset);
- },
- .expression => |expression| blk: {
- context.stack_machine.reset();
- const value = try context.stack_machine.run(
- expression,
- context.allocator,
- expression_context,
- context.cfa,
- );
-
- if (value) |v| {
- if (v != .generic) return error.InvalidExpressionValue;
- break :blk v.generic;
- } else return error.NoExpressionValue;
- },
- else => return error.InvalidCFARule,
- };
-
- if (ma.load(usize, context.cfa.?) == null) return error.InvalidCFA;
- expression_context.cfa = context.cfa;
-
- // Buffering the modifications is done because copying the thread context is not portable,
- // some implementations (ie. darwin) use internal pointers to the mcontext.
- var arena = std.heap.ArenaAllocator.init(context.allocator);
- defer arena.deinit();
- const update_allocator = arena.allocator();
-
- const RegisterUpdate = struct {
- // Backed by thread_context
- dest: []u8,
- // Backed by arena
- src: []const u8,
- prev: ?*@This(),
- };
-
- var update_tail: ?*RegisterUpdate = null;
- var has_return_address = true;
- for (context.vm.rowColumns(row)) |column| {
- if (column.register) |register| {
- if (register == cie.return_address_register) {
- has_return_address = column.rule != .undefined;
- }
-
- const dest = try abi.regBytes(context.thread_context, register, context.reg_context);
- const src = try update_allocator.alloc(u8, dest.len);
-
- const prev = update_tail;
- update_tail = try update_allocator.create(RegisterUpdate);
- update_tail.?.* = .{
- .dest = dest,
- .src = src,
- .prev = prev,
- };
-
- try column.resolveValue(
- context,
- expression_context,
- ma,
- src,
- );
- }
- }
-
- // On all implemented architectures, the CFA is defined as being the previous frame's SP
- (try abi.regValueNative(usize, context.thread_context, abi.spRegNum(context.reg_context), context.reg_context)).* = context.cfa.?;
-
- while (update_tail) |tail| {
- @memcpy(tail.dest, tail.src);
- update_tail = tail.prev;
- }
-
- if (has_return_address) {
- context.pc = abi.stripInstructionPtrAuthCode(mem.readInt(usize, (try abi.regBytes(
- context.thread_context,
- cie.return_address_register,
- context.reg_context,
- ))[0..@sizeOf(usize)], native_endian));
- } else {
- context.pc = 0;
- }
-
- (try abi.regValueNative(usize, context.thread_context, abi.ipRegNum(), context.reg_context)).* = context.pc;
-
- // The call instruction will have pushed the address of the instruction that follows the call as the return address.
- // This next instruction may be past the end of the function if the caller was `noreturn` (ie. the last instruction in
- // the function was the call). If we were to look up an FDE entry using the return address directly, it could end up
- // either not finding an FDE at all, or using the next FDE in the program, producing incorrect results. To prevent this,
- // we subtract one so that the next lookup is guaranteed to land inside the
- //
- // The exception to this rule is signal frames, where we return execution would be returned to the instruction
- // that triggered the handler.
- const return_address = context.pc;
- if (context.pc > 0 and !cie.isSignalFrame()) context.pc -= 1;
-
- return return_address;
- }
-};
-
-/// Returns the DWARF register number for an x86_64 register number found in compact unwind info
-fn compactUnwindToDwarfRegNumber(unwind_reg_number: u3) !u8 {
- return switch (unwind_reg_number) {
- 1 => 3, // RBX
- 2 => 12, // R12
- 3 => 13, // R13
- 4 => 14, // R14
- 5 => 15, // R15
- 6 => 6, // RBP
- else => error.InvalidUnwindRegisterNumber,
- };
-}
-
-const macho = std.macho;
-
-/// Unwind a frame using MachO compact unwind info (from __unwind_info).
-/// If the compact encoding can't encode a way to unwind a frame, it will
-/// defer unwinding to DWARF, in which case `.eh_frame` will be used if available.
-pub fn unwindFrameMachO(
- context: *UnwindContext,
- ma: *debug.StackIterator.MemoryAccessor,
- unwind_info: []const u8,
- eh_frame: ?[]const u8,
- module_base_address: usize,
-) !usize {
- const header = mem.bytesAsValue(
- macho.unwind_info_section_header,
- unwind_info[0..@sizeOf(macho.unwind_info_section_header)],
- );
- const indices = mem.bytesAsSlice(
- macho.unwind_info_section_header_index_entry,
- unwind_info[header.indexSectionOffset..][0 .. header.indexCount * @sizeOf(macho.unwind_info_section_header_index_entry)],
- );
- if (indices.len == 0) return error.MissingUnwindInfo;
-
- const mapped_pc = context.pc - module_base_address;
- const second_level_index = blk: {
- var left: usize = 0;
- var len: usize = indices.len;
-
- while (len > 1) {
- const mid = left + len / 2;
- const offset = indices[mid].functionOffset;
- if (mapped_pc < offset) {
- len /= 2;
- } else {
- left = mid;
- if (mapped_pc == offset) break;
- len -= len / 2;
- }
- }
-
- // Last index is a sentinel containing the highest address as its functionOffset
- if (indices[left].secondLevelPagesSectionOffset == 0) return error.MissingUnwindInfo;
- break :blk &indices[left];
- };
-
- const common_encodings = mem.bytesAsSlice(
- macho.compact_unwind_encoding_t,
- unwind_info[header.commonEncodingsArraySectionOffset..][0 .. header.commonEncodingsArrayCount * @sizeOf(macho.compact_unwind_encoding_t)],
- );
-
- const start_offset = second_level_index.secondLevelPagesSectionOffset;
- const kind = mem.bytesAsValue(
- macho.UNWIND_SECOND_LEVEL,
- unwind_info[start_offset..][0..@sizeOf(macho.UNWIND_SECOND_LEVEL)],
- );
-
- const entry: struct {
- function_offset: usize,
- raw_encoding: u32,
- } = switch (kind.*) {
- .REGULAR => blk: {
- const page_header = mem.bytesAsValue(
- macho.unwind_info_regular_second_level_page_header,
- unwind_info[start_offset..][0..@sizeOf(macho.unwind_info_regular_second_level_page_header)],
- );
-
- const entries = mem.bytesAsSlice(
- macho.unwind_info_regular_second_level_entry,
- unwind_info[start_offset + page_header.entryPageOffset ..][0 .. page_header.entryCount * @sizeOf(macho.unwind_info_regular_second_level_entry)],
- );
- if (entries.len == 0) return error.InvalidUnwindInfo;
-
- var left: usize = 0;
- var len: usize = entries.len;
- while (len > 1) {
- const mid = left + len / 2;
- const offset = entries[mid].functionOffset;
- if (mapped_pc < offset) {
- len /= 2;
- } else {
- left = mid;
- if (mapped_pc == offset) break;
- len -= len / 2;
- }
- }
-
- break :blk .{
- .function_offset = entries[left].functionOffset,
- .raw_encoding = entries[left].encoding,
- };
- },
- .COMPRESSED => blk: {
- const page_header = mem.bytesAsValue(
- macho.unwind_info_compressed_second_level_page_header,
- unwind_info[start_offset..][0..@sizeOf(macho.unwind_info_compressed_second_level_page_header)],
- );
-
- const entries = mem.bytesAsSlice(
- macho.UnwindInfoCompressedEntry,
- unwind_info[start_offset + page_header.entryPageOffset ..][0 .. page_header.entryCount * @sizeOf(macho.UnwindInfoCompressedEntry)],
- );
- if (entries.len == 0) return error.InvalidUnwindInfo;
-
- var left: usize = 0;
- var len: usize = entries.len;
- while (len > 1) {
- const mid = left + len / 2;
- const offset = second_level_index.functionOffset + entries[mid].funcOffset;
- if (mapped_pc < offset) {
- len /= 2;
- } else {
- left = mid;
- if (mapped_pc == offset) break;
- len -= len / 2;
- }
- }
-
- const entry = entries[left];
- const function_offset = second_level_index.functionOffset + entry.funcOffset;
- if (entry.encodingIndex < header.commonEncodingsArrayCount) {
- if (entry.encodingIndex >= common_encodings.len) return error.InvalidUnwindInfo;
- break :blk .{
- .function_offset = function_offset,
- .raw_encoding = common_encodings[entry.encodingIndex],
- };
- } else {
- const local_index = try math.sub(
- u8,
- entry.encodingIndex,
- math.cast(u8, header.commonEncodingsArrayCount) orelse return error.InvalidUnwindInfo,
- );
- const local_encodings = mem.bytesAsSlice(
- macho.compact_unwind_encoding_t,
- unwind_info[start_offset + page_header.encodingsPageOffset ..][0 .. page_header.encodingsCount * @sizeOf(macho.compact_unwind_encoding_t)],
- );
- if (local_index >= local_encodings.len) return error.InvalidUnwindInfo;
- break :blk .{
- .function_offset = function_offset,
- .raw_encoding = local_encodings[local_index],
- };
- }
- },
- else => return error.InvalidUnwindInfo,
- };
-
- if (entry.raw_encoding == 0) return error.NoUnwindInfo;
- const reg_context = abi.RegisterContext{
- .eh_frame = false,
- .is_macho = true,
- };
-
- const encoding: macho.CompactUnwindEncoding = @bitCast(entry.raw_encoding);
- const new_ip = switch (builtin.cpu.arch) {
- .x86_64 => switch (encoding.mode.x86_64) {
- .OLD => return error.UnimplementedUnwindEncoding,
- .RBP_FRAME => blk: {
- const regs: [5]u3 = .{
- encoding.value.x86_64.frame.reg0,
- encoding.value.x86_64.frame.reg1,
- encoding.value.x86_64.frame.reg2,
- encoding.value.x86_64.frame.reg3,
- encoding.value.x86_64.frame.reg4,
- };
-
- const frame_offset = encoding.value.x86_64.frame.frame_offset * @sizeOf(usize);
- var max_reg: usize = 0;
- inline for (regs, 0..) |reg, i| {
- if (reg > 0) max_reg = i;
- }
-
- const fp = (try abi.regValueNative(usize, context.thread_context, abi.fpRegNum(reg_context), reg_context)).*;
- const new_sp = fp + 2 * @sizeOf(usize);
-
- // Verify the stack range we're about to read register values from
- if (ma.load(usize, new_sp) == null or ma.load(usize, fp - frame_offset + max_reg * @sizeOf(usize)) == null) return error.InvalidUnwindInfo;
-
- const ip_ptr = fp + @sizeOf(usize);
- const new_ip = @as(*const usize, @ptrFromInt(ip_ptr)).*;
- const new_fp = @as(*const usize, @ptrFromInt(fp)).*;
-
- (try abi.regValueNative(usize, context.thread_context, abi.fpRegNum(reg_context), reg_context)).* = new_fp;
- (try abi.regValueNative(usize, context.thread_context, abi.spRegNum(reg_context), reg_context)).* = new_sp;
- (try abi.regValueNative(usize, context.thread_context, abi.ipRegNum(), reg_context)).* = new_ip;
-
- for (regs, 0..) |reg, i| {
- if (reg == 0) continue;
- const addr = fp - frame_offset + i * @sizeOf(usize);
- const reg_number = try compactUnwindToDwarfRegNumber(reg);
- (try abi.regValueNative(usize, context.thread_context, reg_number, reg_context)).* = @as(*const usize, @ptrFromInt(addr)).*;
- }
-
- break :blk new_ip;
- },
- .STACK_IMMD,
- .STACK_IND,
- => blk: {
- const sp = (try abi.regValueNative(usize, context.thread_context, abi.spRegNum(reg_context), reg_context)).*;
- const stack_size = if (encoding.mode.x86_64 == .STACK_IMMD)
- @as(usize, encoding.value.x86_64.frameless.stack.direct.stack_size) * @sizeOf(usize)
- else stack_size: {
- // In .STACK_IND, the stack size is inferred from the subq instruction at the beginning of the function.
- const sub_offset_addr =
- module_base_address +
- entry.function_offset +
- encoding.value.x86_64.frameless.stack.indirect.sub_offset;
- if (ma.load(usize, sub_offset_addr) == null) return error.InvalidUnwindInfo;
-
- // `sub_offset_addr` points to the offset of the literal within the instruction
- const sub_operand = @as(*align(1) const u32, @ptrFromInt(sub_offset_addr)).*;
- break :stack_size sub_operand + @sizeOf(usize) * @as(usize, encoding.value.x86_64.frameless.stack.indirect.stack_adjust);
- };
-
- // Decode the Lehmer-coded sequence of registers.
- // For a description of the encoding see lib/libc/include/any-macos.13-any/mach-o/compact_unwind_encoding.h
-
- // Decode the variable-based permutation number into its digits. Each digit represents
- // an index into the list of register numbers that weren't yet used in the sequence at
- // the time the digit was added.
- const reg_count = encoding.value.x86_64.frameless.stack_reg_count;
- const ip_ptr = if (reg_count > 0) reg_blk: {
- var digits: [6]u3 = undefined;
- var accumulator: usize = encoding.value.x86_64.frameless.stack_reg_permutation;
- var base: usize = 2;
- for (0..reg_count) |i| {
- const div = accumulator / base;
- digits[digits.len - 1 - i] = @intCast(accumulator - base * div);
- accumulator = div;
- base += 1;
- }
-
- const reg_numbers = [_]u3{ 1, 2, 3, 4, 5, 6 };
- var registers: [reg_numbers.len]u3 = undefined;
- var used_indices = [_]bool{false} ** reg_numbers.len;
- for (digits[digits.len - reg_count ..], 0..) |target_unused_index, i| {
- var unused_count: u8 = 0;
- const unused_index = for (used_indices, 0..) |used, index| {
- if (!used) {
- if (target_unused_index == unused_count) break index;
- unused_count += 1;
- }
- } else unreachable;
-
- registers[i] = reg_numbers[unused_index];
- used_indices[unused_index] = true;
- }
-
- var reg_addr = sp + stack_size - @sizeOf(usize) * @as(usize, reg_count + 1);
- if (ma.load(usize, reg_addr) == null) return error.InvalidUnwindInfo;
- for (0..reg_count) |i| {
- const reg_number = try compactUnwindToDwarfRegNumber(registers[i]);
- (try abi.regValueNative(usize, context.thread_context, reg_number, reg_context)).* = @as(*const usize, @ptrFromInt(reg_addr)).*;
- reg_addr += @sizeOf(usize);
- }
-
- break :reg_blk reg_addr;
- } else sp + stack_size - @sizeOf(usize);
-
- const new_ip = @as(*const usize, @ptrFromInt(ip_ptr)).*;
- const new_sp = ip_ptr + @sizeOf(usize);
- if (ma.load(usize, new_sp) == null) return error.InvalidUnwindInfo;
-
- (try abi.regValueNative(usize, context.thread_context, abi.spRegNum(reg_context), reg_context)).* = new_sp;
- (try abi.regValueNative(usize, context.thread_context, abi.ipRegNum(), reg_context)).* = new_ip;
-
- break :blk new_ip;
- },
- .DWARF => {
- return unwindFrameMachODwarf(context, ma, eh_frame orelse return error.MissingEhFrame, @intCast(encoding.value.x86_64.dwarf));
- },
- },
- .aarch64 => switch (encoding.mode.arm64) {
- .OLD => return error.UnimplementedUnwindEncoding,
- .FRAMELESS => blk: {
- const sp = (try abi.regValueNative(usize, context.thread_context, abi.spRegNum(reg_context), reg_context)).*;
- const new_sp = sp + encoding.value.arm64.frameless.stack_size * 16;
- const new_ip = (try abi.regValueNative(usize, context.thread_context, 30, reg_context)).*;
- if (ma.load(usize, new_sp) == null) return error.InvalidUnwindInfo;
- (try abi.regValueNative(usize, context.thread_context, abi.spRegNum(reg_context), reg_context)).* = new_sp;
- break :blk new_ip;
- },
- .DWARF => {
- return unwindFrameMachODwarf(context, ma, eh_frame orelse return error.MissingEhFrame, @intCast(encoding.value.arm64.dwarf));
- },
- .FRAME => blk: {
- const fp = (try abi.regValueNative(usize, context.thread_context, abi.fpRegNum(reg_context), reg_context)).*;
- const new_sp = fp + 16;
- const ip_ptr = fp + @sizeOf(usize);
-
- const num_restored_pairs: usize =
- @popCount(@as(u5, @bitCast(encoding.value.arm64.frame.x_reg_pairs))) +
- @popCount(@as(u4, @bitCast(encoding.value.arm64.frame.d_reg_pairs)));
- const min_reg_addr = fp - num_restored_pairs * 2 * @sizeOf(usize);
-
- if (ma.load(usize, new_sp) == null or ma.load(usize, min_reg_addr) == null) return error.InvalidUnwindInfo;
-
- var reg_addr = fp - @sizeOf(usize);
- inline for (@typeInfo(@TypeOf(encoding.value.arm64.frame.x_reg_pairs)).Struct.fields, 0..) |field, i| {
- if (@field(encoding.value.arm64.frame.x_reg_pairs, field.name) != 0) {
- (try abi.regValueNative(usize, context.thread_context, 19 + i, reg_context)).* = @as(*const usize, @ptrFromInt(reg_addr)).*;
- reg_addr += @sizeOf(usize);
- (try abi.regValueNative(usize, context.thread_context, 20 + i, reg_context)).* = @as(*const usize, @ptrFromInt(reg_addr)).*;
- reg_addr += @sizeOf(usize);
- }
- }
-
- inline for (@typeInfo(@TypeOf(encoding.value.arm64.frame.d_reg_pairs)).Struct.fields, 0..) |field, i| {
- if (@field(encoding.value.arm64.frame.d_reg_pairs, field.name) != 0) {
- // Only the lower half of the 128-bit V registers are restored during unwinding
- @memcpy(
- try abi.regBytes(context.thread_context, 64 + 8 + i, context.reg_context),
- mem.asBytes(@as(*const usize, @ptrFromInt(reg_addr))),
- );
- reg_addr += @sizeOf(usize);
- @memcpy(
- try abi.regBytes(context.thread_context, 64 + 9 + i, context.reg_context),
- mem.asBytes(@as(*const usize, @ptrFromInt(reg_addr))),
- );
- reg_addr += @sizeOf(usize);
- }
- }
-
- const new_ip = @as(*const usize, @ptrFromInt(ip_ptr)).*;
- const new_fp = @as(*const usize, @ptrFromInt(fp)).*;
-
- (try abi.regValueNative(usize, context.thread_context, abi.fpRegNum(reg_context), reg_context)).* = new_fp;
- (try abi.regValueNative(usize, context.thread_context, abi.ipRegNum(), reg_context)).* = new_ip;
-
- break :blk new_ip;
- },
- },
- else => return error.UnimplementedArch,
- };
-
- context.pc = abi.stripInstructionPtrAuthCode(new_ip);
- if (context.pc > 0) context.pc -= 1;
- return new_ip;
-}
-
-fn unwindFrameMachODwarf(context: *UnwindContext, ma: *debug.StackIterator.MemoryAccessor, eh_frame: []const u8, fde_offset: usize) !usize {
- var di = DwarfInfo{
- .endian = native_endian,
- .is_macho = true,
- };
- defer di.deinit(context.allocator);
-
- di.sections[@intFromEnum(DwarfSection.eh_frame)] = .{
- .data = eh_frame,
- .owned = false,
- };
-
- return di.unwindFrame(context, ma, fde_offset);
-}
-
-pub const UnwindContext = struct {
- allocator: mem.Allocator,
- cfa: ?usize,
- pc: usize,
- thread_context: *debug.ThreadContext,
- reg_context: abi.RegisterContext,
- vm: call_frame.VirtualMachine,
- stack_machine: expressions.StackMachine(.{ .call_frame_context = true }),
-
- pub fn init(
- allocator: mem.Allocator,
- thread_context: *const debug.ThreadContext,
- ) !UnwindContext {
- const pc = abi.stripInstructionPtrAuthCode(
- (try abi.regValueNative(
- usize,
- thread_context,
- abi.ipRegNum(),
- null,
- )).*,
- );
-
- const context_copy = try allocator.create(debug.ThreadContext);
- debug.copyContext(thread_context, context_copy);
-
- return .{
- .allocator = allocator,
- .cfa = null,
- .pc = pc,
- .thread_context = context_copy,
- .reg_context = undefined,
- .vm = .{},
- .stack_machine = .{},
- };
- }
-
- pub fn deinit(self: *UnwindContext) void {
- self.vm.deinit(self.allocator);
- self.stack_machine.deinit(self.allocator);
- self.allocator.destroy(self.thread_context);
- self.* = undefined;
- }
-
- pub fn getFp(self: *const UnwindContext) !usize {
- return (try abi.regValueNative(usize, self.thread_context, abi.fpRegNum(self.reg_context), self.reg_context)).*;
- }
-};
-
-/// Initialize DWARF info. The caller has the responsibility to initialize most
-/// the DwarfInfo fields before calling. `binary_mem` is the raw bytes of the
-/// main binary file (not the secondary debug info file).
-pub fn openDwarfDebugInfo(di: *DwarfInfo, allocator: mem.Allocator) !void {
- try di.scanAllFunctions(allocator);
- try di.scanAllCompileUnits(allocator);
-}
-
-/// This function is to make it handy to comment out the return and make it
-/// into a crash when working on this file.
-fn badDwarf() error{InvalidDebugInfo} {
- //if (true) @panic("badDwarf"); // can be handy to uncomment when working on this file
- return error.InvalidDebugInfo;
-}
-
-fn missingDwarf() error{MissingDebugInfo} {
- //if (true) @panic("missingDwarf"); // can be handy to uncomment when working on this file
- return error.MissingDebugInfo;
-}
-
-fn getStringGeneric(opt_str: ?[]const u8, offset: u64) ![:0]const u8 {
- const str = opt_str orelse return badDwarf();
- if (offset > str.len) return badDwarf();
- const casted_offset = math.cast(usize, offset) orelse return badDwarf();
- // Valid strings always have a terminating zero byte
- const last = mem.indexOfScalarPos(u8, str, casted_offset, 0) orelse return badDwarf();
- return str[casted_offset..last :0];
-}
-
-const EhPointerContext = struct {
- // The address of the pointer field itself
- pc_rel_base: u64,
-
- // Whether or not to follow indirect pointers. This should only be
- // used when decoding pointers at runtime using the current process's
- // debug info
- follow_indirect: bool,
-
- // These relative addressing modes are only used in specific cases, and
- // might not be available / required in all parsing contexts
- data_rel_base: ?u64 = null,
- text_rel_base: ?u64 = null,
- function_rel_base: ?u64 = null,
-};
-fn readEhPointer(fbr: *FixedBufferReader, enc: u8, addr_size_bytes: u8, ctx: EhPointerContext) !?u64 {
- if (enc == EH.PE.omit) return null;
-
- const value: union(enum) {
- signed: i64,
- unsigned: u64,
- } = switch (enc & EH.PE.type_mask) {
- EH.PE.absptr => .{
- .unsigned = switch (addr_size_bytes) {
- 2 => try fbr.readInt(u16),
- 4 => try fbr.readInt(u32),
- 8 => try fbr.readInt(u64),
- else => return error.InvalidAddrSize,
- },
- },
- EH.PE.uleb128 => .{ .unsigned = try fbr.readUleb128(u64) },
- EH.PE.udata2 => .{ .unsigned = try fbr.readInt(u16) },
- EH.PE.udata4 => .{ .unsigned = try fbr.readInt(u32) },
- EH.PE.udata8 => .{ .unsigned = try fbr.readInt(u64) },
- EH.PE.sleb128 => .{ .signed = try fbr.readIleb128(i64) },
- EH.PE.sdata2 => .{ .signed = try fbr.readInt(i16) },
- EH.PE.sdata4 => .{ .signed = try fbr.readInt(i32) },
- EH.PE.sdata8 => .{ .signed = try fbr.readInt(i64) },
- else => return badDwarf(),
- };
-
- const base = switch (enc & EH.PE.rel_mask) {
- EH.PE.pcrel => ctx.pc_rel_base,
- EH.PE.textrel => ctx.text_rel_base orelse return error.PointerBaseNotSpecified,
- EH.PE.datarel => ctx.data_rel_base orelse return error.PointerBaseNotSpecified,
- EH.PE.funcrel => ctx.function_rel_base orelse return error.PointerBaseNotSpecified,
- else => null,
- };
-
- const ptr: u64 = if (base) |b| switch (value) {
- .signed => |s| @intCast(try math.add(i64, s, @as(i64, @intCast(b)))),
- // absptr can actually contain signed values in some cases (aarch64 MachO)
- .unsigned => |u| u +% b,
- } else switch (value) {
- .signed => |s| @as(u64, @intCast(s)),
- .unsigned => |u| u,
- };
-
- if ((enc & EH.PE.indirect) > 0 and ctx.follow_indirect) {
- if (@sizeOf(usize) != addr_size_bytes) {
- // See the documentation for `follow_indirect`
- return error.NonNativeIndirection;
- }
-
- const native_ptr = math.cast(usize, ptr) orelse return error.PointerOverflow;
- return switch (addr_size_bytes) {
- 2, 4, 8 => return @as(*const usize, @ptrFromInt(native_ptr)).*,
- else => return error.UnsupportedAddrSize,
- };
- } else {
- return ptr;
- }
-}
-
-/// This represents the decoded .eh_frame_hdr header
-pub const ExceptionFrameHeader = struct {
- eh_frame_ptr: usize,
- table_enc: u8,
- fde_count: usize,
- entries: []const u8,
-
- pub fn entrySize(table_enc: u8) !u8 {
- return switch (table_enc & EH.PE.type_mask) {
- EH.PE.udata2,
- EH.PE.sdata2,
- => 4,
- EH.PE.udata4,
- EH.PE.sdata4,
- => 8,
- EH.PE.udata8,
- EH.PE.sdata8,
- => 16,
- // This is a binary search table, so all entries must be the same length
- else => return badDwarf(),
- };
- }
-
- fn isValidPtr(
- self: ExceptionFrameHeader,
- comptime T: type,
- ptr: usize,
- ma: *debug.StackIterator.MemoryAccessor,
- eh_frame_len: ?usize,
- ) bool {
- if (eh_frame_len) |len| {
- return ptr >= self.eh_frame_ptr and ptr <= self.eh_frame_ptr + len - @sizeOf(T);
- } else {
- return ma.load(T, ptr) != null;
- }
- }
-
- /// Find an entry by binary searching the eh_frame_hdr section.
- ///
- /// Since the length of the eh_frame section (`eh_frame_len`) may not be known by the caller,
- /// MemoryAccessor will be used to verify readability of the header entries.
- /// If `eh_frame_len` is provided, then these checks can be skipped.
- pub fn findEntry(
- self: ExceptionFrameHeader,
- ma: *debug.StackIterator.MemoryAccessor,
- eh_frame_len: ?usize,
- eh_frame_hdr_ptr: usize,
- pc: usize,
- cie: *CommonInformationEntry,
- fde: *FrameDescriptionEntry,
- ) !void {
- const entry_size = try entrySize(self.table_enc);
-
- var left: usize = 0;
- var len: usize = self.fde_count;
-
- var fbr: FixedBufferReader = .{ .buf = self.entries, .endian = native_endian };
-
- while (len > 1) {
- const mid = left + len / 2;
-
- fbr.pos = mid * entry_size;
- const pc_begin = try readEhPointer(&fbr, self.table_enc, @sizeOf(usize), .{
- .pc_rel_base = @intFromPtr(&self.entries[fbr.pos]),
- .follow_indirect = true,
- .data_rel_base = eh_frame_hdr_ptr,
- }) orelse return badDwarf();
-
- if (pc < pc_begin) {
- len /= 2;
- } else {
- left = mid;
- if (pc == pc_begin) break;
- len -= len / 2;
- }
- }
-
- if (len == 0) return badDwarf();
- fbr.pos = left * entry_size;
-
- // Read past the pc_begin field of the entry
- _ = try readEhPointer(&fbr, self.table_enc, @sizeOf(usize), .{
- .pc_rel_base = @intFromPtr(&self.entries[fbr.pos]),
- .follow_indirect = true,
- .data_rel_base = eh_frame_hdr_ptr,
- }) orelse return badDwarf();
-
- const fde_ptr = math.cast(usize, try readEhPointer(&fbr, self.table_enc, @sizeOf(usize), .{
- .pc_rel_base = @intFromPtr(&self.entries[fbr.pos]),
- .follow_indirect = true,
- .data_rel_base = eh_frame_hdr_ptr,
- }) orelse return badDwarf()) orelse return badDwarf();
-
- if (fde_ptr < self.eh_frame_ptr) return badDwarf();
-
- // Even if eh_frame_len is not specified, all ranges accssed are checked via MemoryAccessor
- const eh_frame = @as([*]const u8, @ptrFromInt(self.eh_frame_ptr))[0 .. eh_frame_len orelse math.maxInt(u32)];
-
- const fde_offset = fde_ptr - self.eh_frame_ptr;
- var eh_frame_fbr: FixedBufferReader = .{
- .buf = eh_frame,
- .pos = fde_offset,
- .endian = native_endian,
- };
-
- const fde_entry_header = try EntryHeader.read(&eh_frame_fbr, if (eh_frame_len == null) ma else null, .eh_frame);
- if (!self.isValidPtr(u8, @intFromPtr(&fde_entry_header.entry_bytes[fde_entry_header.entry_bytes.len - 1]), ma, eh_frame_len)) return badDwarf();
- if (fde_entry_header.type != .fde) return badDwarf();
-
- // CIEs always come before FDEs (the offset is a subtraction), so we can assume this memory is readable
- const cie_offset = fde_entry_header.type.fde;
- try eh_frame_fbr.seekTo(cie_offset);
- const cie_entry_header = try EntryHeader.read(&eh_frame_fbr, if (eh_frame_len == null) ma else null, .eh_frame);
- if (!self.isValidPtr(u8, @intFromPtr(&cie_entry_header.entry_bytes[cie_entry_header.entry_bytes.len - 1]), ma, eh_frame_len)) return badDwarf();
- if (cie_entry_header.type != .cie) return badDwarf();
-
- cie.* = try CommonInformationEntry.parse(
- cie_entry_header.entry_bytes,
- 0,
- true,
- cie_entry_header.format,
- .eh_frame,
- cie_entry_header.length_offset,
- @sizeOf(usize),
- native_endian,
- );
-
- fde.* = try FrameDescriptionEntry.parse(
- fde_entry_header.entry_bytes,
- 0,
- true,
- cie.*,
- @sizeOf(usize),
- native_endian,
- );
- }
-};
-
-pub const EntryHeader = struct {
- /// Offset of the length field in the backing buffer
- length_offset: usize,
- format: Format,
- type: union(enum) {
- cie,
- /// Value is the offset of the corresponding CIE
- fde: u64,
- terminator,
- },
- /// The entry's contents, not including the ID field
- entry_bytes: []const u8,
-
- /// The length of the entry including the ID field, but not the length field itself
- pub fn entryLength(self: EntryHeader) usize {
- return self.entry_bytes.len + @as(u8, if (self.format == .@"64") 8 else 4);
- }
-
- /// Reads a header for either an FDE or a CIE, then advances the fbr to the position after the trailing structure.
- /// `fbr` must be a FixedBufferReader backed by either the .eh_frame or .debug_frame sections.
- pub fn read(
- fbr: *FixedBufferReader,
- opt_ma: ?*debug.StackIterator.MemoryAccessor,
- dwarf_section: DwarfSection,
- ) !EntryHeader {
- assert(dwarf_section == .eh_frame or dwarf_section == .debug_frame);
-
- const length_offset = fbr.pos;
- const unit_header = try readUnitHeader(fbr, opt_ma);
- const unit_length = math.cast(usize, unit_header.unit_length) orelse return badDwarf();
- if (unit_length == 0) return .{
- .length_offset = length_offset,
- .format = unit_header.format,
- .type = .terminator,
- .entry_bytes = &.{},
- };
- const start_offset = fbr.pos;
- const end_offset = start_offset + unit_length;
- defer fbr.pos = end_offset;
-
- const id = try if (opt_ma) |ma|
- fbr.readAddressChecked(unit_header.format, ma)
- else
- fbr.readAddress(unit_header.format);
- const entry_bytes = fbr.buf[fbr.pos..end_offset];
- const cie_id: u64 = switch (dwarf_section) {
- .eh_frame => CommonInformationEntry.eh_id,
- .debug_frame => switch (unit_header.format) {
- .@"32" => CommonInformationEntry.dwarf32_id,
- .@"64" => CommonInformationEntry.dwarf64_id,
- },
- else => unreachable,
- };
-
- return .{
- .length_offset = length_offset,
- .format = unit_header.format,
- .type = if (id == cie_id) .cie else .{ .fde = switch (dwarf_section) {
- .eh_frame => try math.sub(u64, start_offset, id),
- .debug_frame => id,
- else => unreachable,
- } },
- .entry_bytes = entry_bytes,
- };
- }
-};
-
-pub const CommonInformationEntry = struct {
- // Used in .eh_frame
- pub const eh_id = 0;
-
- // Used in .debug_frame (DWARF32)
- pub const dwarf32_id = math.maxInt(u32);
-
- // Used in .debug_frame (DWARF64)
- pub const dwarf64_id = math.maxInt(u64);
-
- // Offset of the length field of this entry in the eh_frame section.
- // This is the key that FDEs use to reference CIEs.
- length_offset: u64,
- version: u8,
- address_size: u8,
- format: Format,
-
- // Only present in version 4
- segment_selector_size: ?u8,
-
- code_alignment_factor: u32,
- data_alignment_factor: i32,
- return_address_register: u8,
-
- aug_str: []const u8,
- aug_data: []const u8,
- lsda_pointer_enc: u8,
- personality_enc: ?u8,
- personality_routine_pointer: ?u64,
- fde_pointer_enc: u8,
- initial_instructions: []const u8,
-
- pub fn isSignalFrame(self: CommonInformationEntry) bool {
- for (self.aug_str) |c| if (c == 'S') return true;
- return false;
- }
-
- pub fn addressesSignedWithBKey(self: CommonInformationEntry) bool {
- for (self.aug_str) |c| if (c == 'B') return true;
- return false;
- }
-
- pub fn mteTaggedFrame(self: CommonInformationEntry) bool {
- for (self.aug_str) |c| if (c == 'G') return true;
- return false;
- }
-
- /// This function expects to read the CIE starting with the version field.
- /// The returned struct references memory backed by cie_bytes.
- ///
- /// See the FrameDescriptionEntry.parse documentation for the description
- /// of `pc_rel_offset` and `is_runtime`.
- ///
- /// `length_offset` specifies the offset of this CIE's length field in the
- /// .eh_frame / .debug_frame section.
- pub fn parse(
- cie_bytes: []const u8,
- pc_rel_offset: i64,
- is_runtime: bool,
- format: Format,
- dwarf_section: DwarfSection,
- length_offset: u64,
- addr_size_bytes: u8,
- endian: std.builtin.Endian,
- ) !CommonInformationEntry {
- if (addr_size_bytes > 8) return error.UnsupportedAddrSize;
-
- var fbr: FixedBufferReader = .{ .buf = cie_bytes, .endian = endian };
-
- const version = try fbr.readByte();
- switch (dwarf_section) {
- .eh_frame => if (version != 1 and version != 3) return error.UnsupportedDwarfVersion,
- .debug_frame => if (version != 4) return error.UnsupportedDwarfVersion,
- else => return error.UnsupportedDwarfSection,
- }
-
- var has_eh_data = false;
- var has_aug_data = false;
-
- var aug_str_len: usize = 0;
- const aug_str_start = fbr.pos;
- var aug_byte = try fbr.readByte();
- while (aug_byte != 0) : (aug_byte = try fbr.readByte()) {
- switch (aug_byte) {
- 'z' => {
- if (aug_str_len != 0) return badDwarf();
- has_aug_data = true;
- },
- 'e' => {
- if (has_aug_data or aug_str_len != 0) return badDwarf();
- if (try fbr.readByte() != 'h') return badDwarf();
- has_eh_data = true;
- },
- else => if (has_eh_data) return badDwarf(),
- }
-
- aug_str_len += 1;
- }
-
- if (has_eh_data) {
- // legacy data created by older versions of gcc - unsupported here
- for (0..addr_size_bytes) |_| _ = try fbr.readByte();
- }
-
- const address_size = if (version == 4) try fbr.readByte() else addr_size_bytes;
- const segment_selector_size = if (version == 4) try fbr.readByte() else null;
-
- const code_alignment_factor = try fbr.readUleb128(u32);
- const data_alignment_factor = try fbr.readIleb128(i32);
- const return_address_register = if (version == 1) try fbr.readByte() else try fbr.readUleb128(u8);
-
- var lsda_pointer_enc: u8 = EH.PE.omit;
- var personality_enc: ?u8 = null;
- var personality_routine_pointer: ?u64 = null;
- var fde_pointer_enc: u8 = EH.PE.absptr;
-
- var aug_data: []const u8 = &[_]u8{};
- const aug_str = if (has_aug_data) blk: {
- const aug_data_len = try fbr.readUleb128(usize);
- const aug_data_start = fbr.pos;
- aug_data = cie_bytes[aug_data_start..][0..aug_data_len];
-
- const aug_str = cie_bytes[aug_str_start..][0..aug_str_len];
- for (aug_str[1..]) |byte| {
- switch (byte) {
- 'L' => {
- lsda_pointer_enc = try fbr.readByte();
- },
- 'P' => {
- personality_enc = try fbr.readByte();
- personality_routine_pointer = try readEhPointer(&fbr, personality_enc.?, addr_size_bytes, .{
- .pc_rel_base = try pcRelBase(@intFromPtr(&cie_bytes[fbr.pos]), pc_rel_offset),
- .follow_indirect = is_runtime,
- });
- },
- 'R' => {
- fde_pointer_enc = try fbr.readByte();
- },
- 'S', 'B', 'G' => {},
- else => return badDwarf(),
- }
- }
-
- // aug_data_len can include padding so the CIE ends on an address boundary
- fbr.pos = aug_data_start + aug_data_len;
- break :blk aug_str;
- } else &[_]u8{};
-
- const initial_instructions = cie_bytes[fbr.pos..];
- return .{
- .length_offset = length_offset,
- .version = version,
- .address_size = address_size,
- .format = format,
- .segment_selector_size = segment_selector_size,
- .code_alignment_factor = code_alignment_factor,
- .data_alignment_factor = data_alignment_factor,
- .return_address_register = return_address_register,
- .aug_str = aug_str,
- .aug_data = aug_data,
- .lsda_pointer_enc = lsda_pointer_enc,
- .personality_enc = personality_enc,
- .personality_routine_pointer = personality_routine_pointer,
- .fde_pointer_enc = fde_pointer_enc,
- .initial_instructions = initial_instructions,
- };
- }
-};
-
-pub const FrameDescriptionEntry = struct {
- // Offset into eh_frame where the CIE for this FDE is stored
- cie_length_offset: u64,
-
- pc_begin: u64,
- pc_range: u64,
- lsda_pointer: ?u64,
- aug_data: []const u8,
- instructions: []const u8,
-
- /// This function expects to read the FDE starting at the PC Begin field.
- /// The returned struct references memory backed by `fde_bytes`.
- ///
- /// `pc_rel_offset` specifies an offset to be applied to pc_rel_base values
- /// used when decoding pointers. This should be set to zero if fde_bytes is
- /// backed by the memory of a .eh_frame / .debug_frame section in the running executable.
- /// Otherwise, it should be the relative offset to translate addresses from
- /// where the section is currently stored in memory, to where it *would* be
- /// stored at runtime: section base addr - backing data base ptr.
- ///
- /// Similarly, `is_runtime` specifies this function is being called on a runtime
- /// section, and so indirect pointers can be followed.
- pub fn parse(
- fde_bytes: []const u8,
- pc_rel_offset: i64,
- is_runtime: bool,
- cie: CommonInformationEntry,
- addr_size_bytes: u8,
- endian: std.builtin.Endian,
- ) !FrameDescriptionEntry {
- if (addr_size_bytes > 8) return error.InvalidAddrSize;
-
- var fbr: FixedBufferReader = .{ .buf = fde_bytes, .endian = endian };
-
- const pc_begin = try readEhPointer(&fbr, cie.fde_pointer_enc, addr_size_bytes, .{
- .pc_rel_base = try pcRelBase(@intFromPtr(&fde_bytes[fbr.pos]), pc_rel_offset),
- .follow_indirect = is_runtime,
- }) orelse return badDwarf();
-
- const pc_range = try readEhPointer(&fbr, cie.fde_pointer_enc, addr_size_bytes, .{
- .pc_rel_base = 0,
- .follow_indirect = false,
- }) orelse return badDwarf();
-
- var aug_data: []const u8 = &[_]u8{};
- const lsda_pointer = if (cie.aug_str.len > 0) blk: {
- const aug_data_len = try fbr.readUleb128(usize);
- const aug_data_start = fbr.pos;
- aug_data = fde_bytes[aug_data_start..][0..aug_data_len];
-
- const lsda_pointer = if (cie.lsda_pointer_enc != EH.PE.omit)
- try readEhPointer(&fbr, cie.lsda_pointer_enc, addr_size_bytes, .{
- .pc_rel_base = try pcRelBase(@intFromPtr(&fde_bytes[fbr.pos]), pc_rel_offset),
- .follow_indirect = is_runtime,
- })
- else
- null;
-
- fbr.pos = aug_data_start + aug_data_len;
- break :blk lsda_pointer;
- } else null;
-
- const instructions = fde_bytes[fbr.pos..];
- return .{
- .cie_length_offset = cie.length_offset,
- .pc_begin = pc_begin,
- .pc_range = pc_range,
- .lsda_pointer = lsda_pointer,
- .aug_data = aug_data,
- .instructions = instructions,
- };
- }
-};
-
-fn pcRelBase(field_ptr: usize, pc_rel_offset: i64) !usize {
- if (pc_rel_offset < 0) {
- return math.sub(usize, field_ptr, @as(usize, @intCast(-pc_rel_offset)));
- } else {
- return math.add(usize, field_ptr, @as(usize, @intCast(pc_rel_offset)));
- }
-}
-
-// Reading debug info needs to be fast, even when compiled in debug mode,
-// so avoid using a `std.io.FixedBufferStream` which is too slow.
-pub const FixedBufferReader = struct {
- buf: []const u8,
- pos: usize = 0,
- endian: std.builtin.Endian,
-
- pub const Error = error{ EndOfBuffer, Overflow, InvalidBuffer };
-
- fn seekTo(fbr: *FixedBufferReader, pos: u64) Error!void {
- if (pos > fbr.buf.len) return error.EndOfBuffer;
- fbr.pos = @intCast(pos);
- }
-
- fn seekForward(fbr: *FixedBufferReader, amount: u64) Error!void {
- if (fbr.buf.len - fbr.pos < amount) return error.EndOfBuffer;
- fbr.pos += @intCast(amount);
- }
-
- pub inline fn readByte(fbr: *FixedBufferReader) Error!u8 {
- if (fbr.pos >= fbr.buf.len) return error.EndOfBuffer;
- defer fbr.pos += 1;
- return fbr.buf[fbr.pos];
- }
-
- fn readByteSigned(fbr: *FixedBufferReader) Error!i8 {
- return @bitCast(try fbr.readByte());
- }
-
- fn readInt(fbr: *FixedBufferReader, comptime T: type) Error!T {
- const size = @divExact(@typeInfo(T).Int.bits, 8);
- if (fbr.buf.len - fbr.pos < size) return error.EndOfBuffer;
- defer fbr.pos += size;
- return mem.readInt(T, fbr.buf[fbr.pos..][0..size], fbr.endian);
- }
-
- fn readIntChecked(
- fbr: *FixedBufferReader,
- comptime T: type,
- ma: *debug.StackIterator.MemoryAccessor,
- ) Error!T {
- if (ma.load(T, @intFromPtr(fbr.buf[fbr.pos..].ptr)) == null)
- return error.InvalidBuffer;
-
- return readInt(fbr, T);
- }
-
- fn readUleb128(fbr: *FixedBufferReader, comptime T: type) Error!T {
- return std.leb.readUleb128(T, fbr);
- }
-
- fn readIleb128(fbr: *FixedBufferReader, comptime T: type) Error!T {
- return std.leb.readIleb128(T, fbr);
- }
-
- fn readAddress(fbr: *FixedBufferReader, format: Format) Error!u64 {
- return switch (format) {
- .@"32" => try fbr.readInt(u32),
- .@"64" => try fbr.readInt(u64),
- };
- }
-
- fn readAddressChecked(
- fbr: *FixedBufferReader,
- format: Format,
- ma: *debug.StackIterator.MemoryAccessor,
- ) Error!u64 {
- return switch (format) {
- .@"32" => try fbr.readIntChecked(u32, ma),
- .@"64" => try fbr.readIntChecked(u64, ma),
- };
- }
-
- fn readBytes(fbr: *FixedBufferReader, len: usize) Error![]const u8 {
- if (fbr.buf.len - fbr.pos < len) return error.EndOfBuffer;
- defer fbr.pos += len;
- return fbr.buf[fbr.pos..][0..len];
- }
-
- fn readBytesTo(fbr: *FixedBufferReader, comptime sentinel: u8) Error![:sentinel]const u8 {
- const end = @call(.always_inline, mem.indexOfScalarPos, .{
- u8,
- fbr.buf,
- fbr.pos,
- sentinel,
- }) orelse return error.EndOfBuffer;
- defer fbr.pos = end + 1;
- return fbr.buf[fbr.pos..end :sentinel];
- }
-};
-
-test {
- std.testing.refAllDecls(@This());
-}
src/target.zig
@@ -327,7 +327,7 @@ pub fn clangAssemblerSupportsMcpuArg(target: std.Target) bool {
}
pub fn needUnwindTables(target: std.Target) bool {
- return target.os.tag == .windows or target.isDarwin() or std.dwarf.abi.supportsUnwinding(target);
+ return target.os.tag == .windows or target.isDarwin() or std.debug.Dwarf.abi.supportsUnwinding(target);
}
pub fn defaultAddressSpace(