Commit 7b4611cfb3
Changed files (2)
lib
std
lib/std/dwarf/call_frame.zig
@@ -1,9 +1,11 @@
+const builtin = @import("builtin");
const std = @import("../std.zig");
const debug = std.debug;
const leb = @import("../leb128.zig");
const abi = @import("abi.zig");
const dwarf = @import("../dwarf.zig");
const expressions = @import("expressions.zig");
+const assert = std.debug.assert;
const Opcode = enum(u8) {
advance_loc = 0x1 << 6,
@@ -36,7 +38,7 @@ const Opcode = enum(u8) {
// These opcodes encode an operand in the lower 6 bits of the opcode itself
pub const lo_inline = Opcode.advance_loc;
- pub const hi_inline = Opcode.restore;
+ pub const hi_inline = @enumToInt(Opcode.restore) | 0b111111;
// These opcodes are trailed by zero or more operands
pub const lo_reserved = Opcode.nop;
@@ -61,7 +63,7 @@ const Operand = enum {
fn Storage(comptime self: Operand) type {
return switch (self) {
- .opcode_delta, .opcode_register => u6,
+ .opcode_delta, .opcode_register => u8,
.uleb128_register => u8,
.uleb128_offset => u64,
.sleb128_offset => i64,
@@ -110,7 +112,7 @@ const Operand = enum {
fn InstructionType(comptime definition: anytype) type {
const definition_type = @typeInfo(@TypeOf(definition));
- debug.assert(definition_type == .Struct);
+ assert(definition_type == .Struct);
const definition_len = definition_type.Struct.fields.len;
comptime var fields: [definition_len]std.builtin.Type.StructField = undefined;
@@ -159,14 +161,14 @@ fn InstructionType(comptime definition: anytype) type {
pub const Instruction = union(Opcode) {
advance_loc: InstructionType(.{ .delta = .opcode_delta }),
offset: InstructionType(.{ .register = .opcode_register, .offset = .uleb128_offset }),
+ offset_extended: InstructionType(.{ .register = .uleb128_register, .offset = .uleb128_offset }),
restore: InstructionType(.{ .register = .opcode_register }),
+ restore_extended: InstructionType(.{ .register = .uleb128_register }),
nop: InstructionType(.{}),
set_loc: InstructionType(.{ .address = .address }),
advance_loc1: InstructionType(.{ .delta = .u8_delta }),
advance_loc2: InstructionType(.{ .delta = .u16_delta }),
advance_loc4: InstructionType(.{ .delta = .u32_delta }),
- offset_extended: InstructionType(.{ .register = .uleb128_register, .offset = .uleb128_offset }),
- restore_extended: InstructionType(.{ .register = .uleb128_register }),
undefined: InstructionType(.{ .register = .uleb128_register }),
same_value: InstructionType(.{ .register = .uleb128_register }),
register: InstructionType(.{ .register = .uleb128_register, .offset = .uleb128_offset }),
@@ -192,7 +194,7 @@ pub const Instruction = union(Opcode) {
@setEvalBranchQuota(1800);
return switch (try stream.reader().readByte()) {
- inline @enumToInt(Opcode.lo_inline)...@enumToInt(Opcode.hi_inline) => |opcode| blk: {
+ inline @enumToInt(Opcode.lo_inline)...Opcode.hi_inline => |opcode| blk: {
const e = @intToEnum(Opcode, opcode & 0b11000000);
const payload_type = std.meta.TagPayload(Instruction, e);
const value = try payload_type.read(stream, @intCast(u6, opcode & 0b111111), addr_size_bytes, endian);
@@ -205,112 +207,15 @@ pub const Instruction = union(Opcode) {
break :blk @unionInit(Instruction, @tagName(e), value);
},
Opcode.lo_user...Opcode.hi_user => error.UnimplementedUserOpcode,
- else => error.InvalidOpcode,
- };
- }
+ else => |opcode| blk: {
+ std.debug.print("Opcode {x}\n", .{opcode});
- pub fn writeOperands(
- self: Instruction,
- writer: anytype,
- cie: dwarf.CommonInformationEntry,
- arch: ?std.Target.Cpu.Arch,
- addr_size_bytes: u8,
- endian: std.builtin.Endian,
- ) !void {
- switch (self) {
- inline .advance_loc, .advance_loc1, .advance_loc2, .advance_loc4 => |i| try writer.print("{}", .{i.operands.delta * cie.code_alignment_factor}),
- .offset => |i| {
- try abi.writeRegisterName(writer, arch, i.operands.register);
- try writer.print(" {}", .{@intCast(i64, i.operands.offset) * cie.data_alignment_factor});
+ break :blk error.InvalidOpcode;
},
- .restore => {},
- .nop => {},
- .set_loc => {},
- .offset_extended => {},
- .restore_extended => {},
- .undefined => {},
- .same_value => {},
- .register => {},
- .remember_state => {},
- .restore_state => {},
- .def_cfa => |i| try writer.print("{} {d:<1}", .{ abi.fmtRegister(i.operands.register, arch), @intCast(i64, i.operands.offset)}),
- .def_cfa_register => |i| try abi.writeRegisterName(writer, arch, i.operands.register),
- .def_cfa_offset => |i| try writer.print("{d:<1}", .{@intCast(i64, i.operands.offset)}),
- .def_cfa_expression => |i| try writeExpression(writer, i.operands.block, arch, addr_size_bytes, endian),
- .expression => {},
- .offset_extended_sf => {},
- .def_cfa_sf => {},
- .def_cfa_offset_sf => {},
- .val_offset => {},
- .val_offset_sf => {},
- .val_expression => {},
- }
+ };
}
};
-fn writeExpression(
- writer: anytype,
- block: []const u8,
- arch: ?std.Target.Cpu.Arch,
- addr_size_bytes: u8,
- endian: std.builtin.Endian,
-) !void {
- var stream = std.io.fixedBufferStream(block);
-
- // Generate a lookup table from opcode value to name
- const opcode_lut_len = 256;
- const opcode_lut: [opcode_lut_len]?[]const u8 = comptime blk: {
- var lut: [opcode_lut_len]?[]const u8 = [_]?[]const u8{null} ** opcode_lut_len;
- for (@typeInfo(dwarf.OP).Struct.decls) |decl| {
- lut[@as(u8, @field(dwarf.OP, decl.name))] = decl.name;
- }
-
- break :blk lut;
- };
-
- switch (endian) {
- inline .Little, .Big => |e| {
- switch (addr_size_bytes) {
- inline 2, 4, 8 => |size| {
- const StackMachine = expressions.StackMachine(.{
- .addr_size = size,
- .endian = e,
- .call_frame_mode = true,
- });
-
- const reader = stream.reader();
- while (stream.pos < stream.buffer.len) {
- if (stream.pos > 0) try writer.writeAll(", ");
-
- const opcode = try reader.readByte();
- if (opcode_lut[opcode]) |opcode_name| {
- try writer.print("DW_OP_{s}", .{opcode_name});
- } else {
- // TODO: See how llvm-dwarfdump prints these?
- if (opcode >= dwarf.OP.lo_user and opcode <= dwarf.OP.lo_user) {
- try writer.print("<unknown vendor opcode: 0x{x}>", .{opcode});
- } else {
- try writer.print("<invalid opcode: 0x{x}>", .{opcode});
- }
- }
-
- if (try StackMachine.readOperand(&stream, opcode)) |value| {
- switch (value) {
- //.generic => |v| try writer.print("{d}", .{v}),
- .generic => {}, // Constant values are implied by the opcode name
- .register => |v| try writer.print(" {}", .{ abi.fmtRegister(v, arch) }),
- .base_register => |v| try writer.print(" {}{d:<1}", .{ abi.fmtRegister(v.base_register, arch), v.offset }),
- else => try writer.print(" TODO({s})", .{@tagName(value)}),
- }
- }
- }
- },
- else => return error.InvalidAddrSize,
- }
- },
- }
-}
-
/// See section 6.4.1 of the DWARF5 specification
pub const VirtualMachine = struct {
const RegisterRule = union(enum) {
@@ -324,52 +229,6 @@ pub const VirtualMachine = struct {
architectural: void,
};
- pub const Column = struct {
- register: u8 = undefined,
- rule: RegisterRule = .{ .undefined = {} },
-
- pub fn writeRule(
- self: Column,
- writer: anytype,
- is_cfa: bool,
- arch: ?std.Target.Cpu.Arch,
- addr_size_bytes: u8,
- endian: std.builtin.Endian,
- ) !void {
- if (is_cfa) {
- try writer.writeAll("CFA");
- } else {
- try abi.writeRegisterName(writer, arch, self.register);
- }
-
- try writer.writeByte('=');
- switch (self.rule) {
- .undefined => {},
- .same_value => try writer.writeAll("S"),
- .offset => |offset| {
- if (is_cfa) {
- try abi.writeRegisterName(writer, arch, self.register);
- try writer.print("{d:<1}", .{offset});
- } else {
- try writer.print("[CFA{d:<1}]", .{offset});
- }
- },
- .val_offset => |offset| {
- if (is_cfa) {
- try abi.writeRegisterName(writer, arch, self.register);
- try writer.print("{d:<1}", .{offset});
- } else {
- try writer.print("CFA{d:<1}", .{offset});
- }
- },
- .register => |register| try abi.writeRegisterName(writer, arch, register),
- .expression => |expression| try writeExpression(writer, expression, arch, addr_size_bytes, endian),
- .val_expression => try writer.writeAll("TODO(val_expression)"),
- .architectural => try writer.writeAll("TODO(architectural)"),
- }
- }
- };
-
/// Each row contains unwinding rules for a set of registers at a specific location in the
pub const Row = struct {
/// Offset from pc_begin
@@ -381,6 +240,12 @@ pub const VirtualMachine = struct {
columns: ColumnRange = .{},
};
+ pub const Column = struct {
+ /// Register can only null in the case of the CFA column
+ register: ?u8 = null,
+ rule: RegisterRule = .{ .undefined = {} },
+ };
+
const ColumnRange = struct {
/// Index into `columns` of the first column in this row.
start: usize = undefined,
@@ -391,10 +256,14 @@ pub const VirtualMachine = struct {
stack: std.ArrayListUnmanaged(ColumnRange) = .{},
current_row: Row = .{},
+ /// The result of executing the CIE's initial_instructions
+ cie_row: ?Row = null,
+
pub fn reset(self: *VirtualMachine) void {
self.stack.clearRetainingCapacity();
self.columns.clearRetainingCapacity();
self.current_row = .{};
+ self.cie_row = null;
}
pub fn deinit(self: *VirtualMachine, allocator: std.mem.Allocator) void {
@@ -403,12 +272,14 @@ pub const VirtualMachine = struct {
self.* = undefined;
}
- pub fn getColumns(self: VirtualMachine, row: Row) []Column {
+ /// Return a slice backed by the row's non-CFA columns
+ pub fn rowColumns(self: VirtualMachine, row: Row) []Column {
return self.columns.items[row.columns.start..][0..row.columns.len];
}
+ /// Either retrieves or adds a column for `register` (non-CFA) in the current row
fn getOrAddColumn(self: *VirtualMachine, allocator: std.mem.Allocator, register: u8) !*Column {
- for (self.getColumns(self.current_row)) |*c| {
+ for (self.rowColumns(self.current_row)) |*c| {
if (c.register == register) return c;
}
@@ -425,20 +296,82 @@ pub const VirtualMachine = struct {
return column;
}
- pub fn step(self: *VirtualMachine, allocator: std.mem.Allocator, cie: dwarf.CommonInformationEntry, instruction: Instruction) !void {
+ /// Runs the CIE instructions, then the FDE instructions. Execution halts
+ /// once the row that corresponds to `pc` is known, and it is returned.
+ pub fn unwindTo(
+ self: *VirtualMachine,
+ allocator: std.mem.Allocator,
+ pc: u64,
+ cie: dwarf.CommonInformationEntry,
+ fde: dwarf.FrameDescriptionEntry,
+ addr_size_bytes: u8,
+ endian: std.builtin.Endian,
+ ) !Row {
+ assert(self.cie_row == null);
+ if (pc < fde.pc_begin or pc >= fde.pc_begin + fde.pc_range) return error.AddressOutOfRange;
+
+ var prev_row: Row = self.current_row;
+ const streams = .{
+ std.io.fixedBufferStream(cie.initial_instructions),
+ std.io.fixedBufferStream(fde.instructions),
+ };
+
+ outer: for (streams, 0..) |*stream, i| {
+ while (stream.pos < stream.buffer.len) {
+ const instruction = try 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) {
+ break :outer;
+ }
+ }
+ }
+
+ return prev_row;
+ }
+
+ pub fn unwindToNative(
+ self: *VirtualMachine,
+ allocator: std.mem.Allocator,
+ pc: u64,
+ cie: dwarf.CommonInformationEntry,
+ fde: dwarf.FrameDescriptionEntry,
+ ) void {
+ self.stepTo(allocator, pc, cie, fde, @sizeOf(usize), builtin.target.cpu.arch.endian());
+ }
+
+ /// Executes a single instruction.
+ /// If this instruction is from the CIE, `is_initial` should be set.
+ /// Returns the value of `current_row` before executing this instruction
+ pub fn step(
+ self: *VirtualMachine,
+ allocator: std.mem.Allocator,
+ cie: dwarf.CommonInformationEntry,
+ is_initial: bool,
+ instruction: Instruction,
+ ) !Row {
+ // CIE instructions must be run before FDE instructions
+ assert(!is_initial or self.cie_row == null);
+ if (!is_initial and self.cie_row == null) self.cie_row = self.current_row;
+
+ const prev_row = self.current_row;
switch (instruction) {
inline .advance_loc, .advance_loc1, .advance_loc2, .advance_loc4 => |i| {
self.current_row.offset += i.operands.delta * cie.code_alignment_factor;
},
- .offset => |i| {
+ inline .offset, .offset_extended => |i| {
const column = try self.getOrAddColumn(allocator, i.operands.register);
column.rule = .{ .offset = @intCast(i64, i.operands.offset) * cie.data_alignment_factor };
},
- .restore => {},
+ inline .restore, .restore_extended => |i| {
+ if (self.cie_row) |cie_row| {
+ const column = try self.getOrAddColumn(allocator, i.operands.register);
+ column.rule = for (self.rowColumns(cie_row)) |cie_column| {
+ if (cie_column.register == i.operands.register) break cie_column.rule;
+ } else .{ .undefined = {} };
+ } else return error.InvalidOperation;
+ },
.nop => {},
.set_loc => {},
- .offset_extended => {},
- .restore_extended => {},
.undefined => {},
.same_value => {},
.register => {},
@@ -448,17 +381,19 @@ pub const VirtualMachine = struct {
const new_start = self.columns.items.len;
if (self.current_row.columns.len > 0) {
- // Since we're copying from the same backing array, ensure it won't be reallocated
try self.columns.ensureUnusedCapacity(allocator, self.current_row.columns.len);
- self.columns.appendSliceAssumeCapacity(self.getColumns(self.current_row));
+ self.columns.appendSliceAssumeCapacity(self.rowColumns(self.current_row));
self.current_row.columns.start = new_start;
}
},
.restore_state => {
- // TODO: Is it possible to remove the duplicate from above? Other instructions may have added columns since then though
- const columns = self.stack.popOrNull() orelse return error.InvalidOperation;
- self.current_row.columns.len = columns.len;
- self.current_row.columns.start = columns.start;
+ const restored_columns = self.stack.popOrNull() orelse return error.InvalidOperation;
+ self.columns.shrinkRetainingCapacity(self.columns.items.len - self.current_row.columns.len);
+ try self.columns.ensureUnusedCapacity(allocator, restored_columns.len);
+
+ self.current_row.columns.start = self.columns.items.len;
+ self.current_row.columns.len = restored_columns.len;
+ self.columns.appendSliceAssumeCapacity(self.columns.items[restored_columns.start..][0..restored_columns.len]);
},
.def_cfa => |i| {
self.current_row.cfa = .{
@@ -488,5 +423,7 @@ pub const VirtualMachine = struct {
.val_offset_sf => {},
.val_expression => {},
}
+
+ return prev_row;
}
};
lib/std/dwarf.zig
@@ -16,6 +16,7 @@ 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 LLE = struct {
pub const end_of_list = 0x00;