Commit 1392a7af17
Changed files (6)
lib
lib/std/debug/SelfInfo/DarwinModule.zig
@@ -252,10 +252,11 @@ pub fn getSymbolAtAddress(module: *const DarwinModule, gpa: Allocator, di: *Debu
};
}
pub const supports_unwinding: bool = true;
+pub const UnwindContext = std.debug.SelfInfo.DwarfUnwindContext;
/// 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 unwindFrame(module: *const DarwinModule, gpa: Allocator, di: *DebugInfo, context: *DwarfUnwindContext) Error!usize {
+pub fn unwindFrame(module: *const DarwinModule, gpa: Allocator, di: *DebugInfo, context: *UnwindContext) Error!usize {
return unwindFrameInner(module, gpa, di, context) catch |err| switch (err) {
error.InvalidDebugInfo,
error.MissingDebugInfo,
@@ -274,7 +275,7 @@ pub fn unwindFrame(module: *const DarwinModule, gpa: Allocator, di: *DebugInfo,
=> return error.InvalidDebugInfo,
};
}
-fn unwindFrameInner(module: *const DarwinModule, gpa: Allocator, di: *DebugInfo, context: *DwarfUnwindContext) !usize {
+fn unwindFrameInner(module: *const DarwinModule, gpa: Allocator, di: *DebugInfo, context: *UnwindContext) !usize {
if (di.unwind == null) di.unwind = module.loadUnwindInfo();
const unwind = &di.unwind.?;
@@ -575,7 +576,7 @@ fn unwindFrameInner(module: *const DarwinModule, gpa: Allocator, di: *DebugInfo,
else => comptime unreachable, // unimplemented
};
- context.pc = DwarfUnwindContext.stripInstructionPtrAuthCode(new_ip);
+ context.pc = UnwindContext.stripInstructionPtrAuthCode(new_ip);
if (context.pc > 0) context.pc -= 1;
return new_ip;
}
@@ -819,7 +820,6 @@ const macho = std.macho;
const mem = std.mem;
const posix = std.posix;
const testing = std.testing;
-const DwarfUnwindContext = std.debug.SelfInfo.DwarfUnwindContext;
const Error = std.debug.SelfInfo.Error;
const regBytes = Dwarf.abi.regBytes;
const regValueNative = Dwarf.abi.regValueNative;
lib/std/debug/SelfInfo/ElfModule.zig
@@ -193,7 +193,7 @@ fn loadUnwindInfo(module: *const ElfModule, gpa: Allocator, di: *DebugInfo) Erro
else => unreachable,
}
}
-pub fn unwindFrame(module: *const ElfModule, gpa: Allocator, di: *DebugInfo, context: *DwarfUnwindContext) Error!usize {
+pub fn unwindFrame(module: *const ElfModule, gpa: Allocator, di: *DebugInfo, context: *UnwindContext) Error!usize {
if (di.unwind[0] == null) try module.loadUnwindInfo(gpa, di);
std.debug.assert(di.unwind[0] != null);
for (&di.unwind) |*opt_unwind| {
@@ -205,6 +205,7 @@ pub fn unwindFrame(module: *const ElfModule, gpa: Allocator, di: *DebugInfo, con
}
return error.MissingDebugInfo;
}
+pub const UnwindContext = std.debug.SelfInfo.DwarfUnwindContext;
pub const supports_unwinding: bool = s: {
const archs: []const std.Target.Cpu.Arch = switch (builtin.target.os.tag) {
.linux => &.{ .x86, .x86_64, .arm, .armeb, .thumb, .thumbeb, .aarch64, .aarch64_be },
@@ -233,7 +234,6 @@ const Allocator = std.mem.Allocator;
const Dwarf = std.debug.Dwarf;
const elf = std.elf;
const mem = std.mem;
-const DwarfUnwindContext = std.debug.SelfInfo.DwarfUnwindContext;
const Error = std.debug.SelfInfo.Error;
const builtin = @import("builtin");
lib/std/debug/SelfInfo/WindowsModule.zig
@@ -102,7 +102,7 @@ fn loadDebugInfo(module: *const WindowsModule, gpa: Allocator, di: *DebugInfo) !
if (create_section_rc != .SUCCESS) return error.MissingDebugInfo;
errdefer windows.CloseHandle(section_handle);
var coff_len: usize = 0;
- var section_view_ptr: [*]const u8 = undefined;
+ var section_view_ptr: ?[*]const u8 = null;
const map_section_rc = windows.ntdll.NtMapViewOfSection(
section_handle,
process_handle,
@@ -116,8 +116,8 @@ fn loadDebugInfo(module: *const WindowsModule, gpa: Allocator, di: *DebugInfo) !
windows.PAGE_READONLY,
);
if (map_section_rc != .SUCCESS) return error.MissingDebugInfo;
- errdefer assert(windows.ntdll.NtUnmapViewOfSection(process_handle, @constCast(section_view_ptr)) == .SUCCESS);
- const section_view = section_view_ptr[0..coff_len];
+ errdefer assert(windows.ntdll.NtUnmapViewOfSection(process_handle, @constCast(section_view_ptr.?)) == .SUCCESS);
+ const section_view = section_view_ptr.?[0..coff_len];
coff_obj = coff.Coff.init(section_view, false) catch return error.InvalidDebugInfo;
di.mapped_file = .{
.file = coff_file,
@@ -246,7 +246,116 @@ pub const DebugInfo = struct {
};
}
};
-pub const supports_unwinding: bool = false;
+
+pub const supports_unwinding: bool = true;
+pub const UnwindContext = switch (builtin.cpu.arch) {
+ .x86 => struct {
+ pc: usize,
+ frames: []usize,
+ frames_capacity: usize,
+ next_index: usize,
+ /// Marked `noinline` to ensure that `RtlCaptureStackBackTrace` includes our caller.
+ pub noinline fn init(ctx: *windows.CONTEXT, gpa: Allocator) Allocator.Error!UnwindContext {
+ const frames_buf = try gpa.alloc(usize, 1024);
+ errdefer comptime unreachable;
+ const frames_len = windows.ntdll.RtlCaptureStackBackTrace(0, frames_buf.len, @ptrCast(frames_buf.ptr), null);
+ const regs = ctx.getRegs();
+ const first_index = for (frames_buf[0..frames_len], 0..) |ret_addr, idx| {
+ if (ret_addr == regs.ip) break idx;
+ } else i: {
+ // If we were called by an exception handler, `regs.ip` wasn't in the trace because
+ // RtlCaptureStackBackTrace omits the KiUserExceptionDispatcher frame, which is the
+ // one in `regs.ip`. In that case, we have to start one frame shallower instead, and
+ // we can figure out that frame's ip from the context's bp.
+ const start_addr_ptr: *const usize = @ptrFromInt(regs.bp + 4);
+ const start_addr = start_addr_ptr.*;
+ for (frames_buf[0..frames_len], 0..) |ret_addr, idx| {
+ if (ret_addr == start_addr) break :i idx;
+ }
+ // The IP in the context can't be found; return an empty trace.
+ gpa.free(frames_buf);
+ return .{ .pc = 0, .frames = &.{}, .frames_capacity = 0, .next_index = 0 };
+ };
+ return .{
+ .pc = @returnAddress(),
+ .frames = frames_buf[0..frames_len],
+ .frames_capacity = 0,
+ .next_index = first_index,
+ };
+ }
+ pub fn deinit(ctx: *UnwindContext, gpa: Allocator) void {
+ gpa.free(ctx.frames.ptr[0..ctx.frames_capacity]);
+ ctx.* = undefined;
+ }
+ pub fn getFp(ctx: *UnwindContext) usize {
+ _ = ctx;
+ return 0;
+ }
+ },
+ else => struct {
+ pc: usize,
+ cur: windows.CONTEXT,
+ history_table: windows.UNWIND_HISTORY_TABLE,
+ pub fn init(ctx: *const windows.CONTEXT, gpa: Allocator) Allocator.Error!UnwindContext {
+ _ = gpa;
+ return .{
+ .pc = @returnAddress(),
+ .cur = ctx.*,
+ .history_table = std.mem.zeroes(windows.UNWIND_HISTORY_TABLE),
+ };
+ }
+ pub fn deinit(ctx: *UnwindContext, gpa: Allocator) void {
+ _ = ctx;
+ _ = gpa;
+ }
+ pub fn getFp(ctx: *UnwindContext) usize {
+ return ctx.cur.getRegs().bp;
+ }
+ },
+};
+pub fn unwindFrame(module: *const WindowsModule, gpa: Allocator, di: *DebugInfo, context: *UnwindContext) !usize {
+ _ = module;
+ _ = gpa;
+ _ = di;
+
+ if (builtin.cpu.arch == .x86) {
+ const i = context.next_index;
+ if (i == context.frames.len) return 0;
+ context.next_index += 1;
+ const ip = context.frames[i];
+ context.pc = ip -| 1;
+ return ip;
+ }
+
+ const current_regs = context.cur.getRegs();
+ var image_base: windows.DWORD64 = undefined;
+ if (windows.ntdll.RtlLookupFunctionEntry(current_regs.ip, &image_base, &context.history_table)) |runtime_function| {
+ var handler_data: ?*anyopaque = null;
+ var establisher_frame: u64 = undefined;
+ _ = windows.ntdll.RtlVirtualUnwind(
+ windows.UNW_FLAG_NHANDLER,
+ image_base,
+ current_regs.ip,
+ runtime_function,
+ &context.cur,
+ &handler_data,
+ &establisher_frame,
+ null,
+ );
+ } else {
+ // leaf function
+ context.cur.setIp(@as(*const usize, @ptrFromInt(current_regs.sp)).*);
+ context.cur.setSp(current_regs.sp + @sizeOf(usize));
+ }
+
+ const next_regs = context.cur.getRegs();
+ const tib = &windows.teb().NtTib;
+ if (next_regs.sp < @intFromPtr(tib.StackLimit) or next_regs.sp > @intFromPtr(tib.StackBase)) {
+ return 0;
+ }
+ context.pc = next_regs.ip -| 1;
+ return next_regs.ip;
+}
const WindowsModule = @This();
lib/std/debug/Dwarf.zig
@@ -282,13 +282,13 @@ pub const Die = struct {
.@"32" => {
const byte_offset = compile_unit.str_offsets_base + 4 * index;
if (byte_offset + 4 > debug_str_offsets.len) return bad();
- const offset = mem.readInt(u32, debug_str_offsets[byte_offset..][0..4], endian);
+ const offset = mem.readInt(u32, debug_str_offsets[@intCast(byte_offset)..][0..4], 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 bad();
- const offset = mem.readInt(u64, debug_str_offsets[byte_offset..][0..8], endian);
+ const offset = mem.readInt(u64, debug_str_offsets[@intCast(byte_offset)..][0..8], endian);
return getStringGeneric(opt_str, offset);
},
}
lib/std/debug/SelfInfo.zig
@@ -42,6 +42,8 @@ pub const target_supported: bool = Module != void;
/// For whether DWARF unwinding is *theoretically* possible, see `Dwarf.abi.supportsUnwinding`.
pub const supports_unwinding: bool = Module.supports_unwinding;
+pub const UnwindContext = if (supports_unwinding) Module.UnwindContext;
+
pub const init: SelfInfo = .{
.modules = .empty,
.lookup_cache = if (Module.LookupCache != void) .init,
@@ -53,7 +55,7 @@ pub fn deinit(self: *SelfInfo, gpa: Allocator) void {
if (Module.LookupCache != void) self.lookup_cache.deinit(gpa);
}
-pub fn unwindFrame(self: *SelfInfo, gpa: Allocator, context: *DwarfUnwindContext) Error!usize {
+pub fn unwindFrame(self: *SelfInfo, gpa: Allocator, context: *UnwindContext) Error!usize {
comptime assert(supports_unwinding);
const module: Module = try .lookup(&self.lookup_cache, gpa, context.pc);
const gop = try self.modules.getOrPut(gpa, module.key());
@@ -113,14 +115,23 @@ pub fn getModuleNameForAddress(self: *SelfInfo, gpa: Allocator, address: usize)
/// ) SelfInfo.Error!std.debug.Symbol;
/// /// Whether a reliable stack unwinding strategy, such as DWARF unwinding, is available.
/// pub const supports_unwinding: bool;
+/// /// Only required if `supports_unwinding == true`.
+/// pub const UnwindContext = struct {
+/// /// A PC value inside the function of the last unwound frame.
+/// pc: usize,
+/// pub fn init(tc: *std.debug.ThreadContext, gpa: Allocator) Allocator.Error!UnwindContext;
+/// pub fn deinit(uc: *UnwindContext, gpa: Allocator) void;
+/// /// Returns the frame pointer associated with the last unwound stack frame. If the frame
+/// /// pointer is unknown, 0 may be returned instead.
+/// pub fn getFp(uc: *UnwindContext) usize;
+/// };
/// /// Only required if `supports_unwinding == true`. Unwinds a single stack frame and returns
-/// /// the next return address (which may be 0 indicating end of stack). This is currently
-/// /// specialized to DWARF unwinding.
+/// /// the next return address (which may be 0 indicating end of stack).
/// pub fn unwindFrame(
/// mod: *const Module,
/// gpa: Allocator,
/// di: *DebugInfo,
-/// ctx: *SelfInfo.DwarfUnwindContext,
+/// ctx: *UnwindContext,
/// ) SelfInfo.Error!usize;
/// ```
const Module: type = Module: {
@@ -136,6 +147,8 @@ const Module: type = Module: {
};
};
+/// An implementation of `UnwindContext` useful for DWARF-based unwinders. The `Module.unwindFrame`
+/// implementation should wrap `DwarfUnwindContext.unwindFrame`.
pub const DwarfUnwindContext = struct {
cfa: ?usize,
pc: usize,
@@ -144,8 +157,9 @@ pub const DwarfUnwindContext = struct {
vm: Dwarf.Unwind.VirtualMachine,
stack_machine: Dwarf.expression.StackMachine(.{ .call_frame_context = true }),
- pub fn init(thread_context: *std.debug.ThreadContext) DwarfUnwindContext {
+ pub fn init(thread_context: *std.debug.ThreadContext, gpa: Allocator) error{}!DwarfUnwindContext {
comptime assert(supports_unwinding);
+ _ = gpa;
const ip_reg_num = Dwarf.abi.ipRegNum(native_arch).?;
const raw_pc_ptr = regValueNative(thread_context, ip_reg_num, null) catch {
@@ -169,8 +183,8 @@ pub const DwarfUnwindContext = struct {
self.* = undefined;
}
- pub fn getFp(self: *const DwarfUnwindContext) !usize {
- return (try regValueNative(self.thread_context, Dwarf.abi.fpRegNum(native_arch, self.reg_context), self.reg_context)).*;
+ pub fn getFp(self: *const DwarfUnwindContext) usize {
+ return (regValueNative(self.thread_context, Dwarf.abi.fpRegNum(native_arch, self.reg_context), self.reg_context) catch return 0).*;
}
/// Resolves the register rule and places the result into `out` (see regBytes)
lib/std/debug.zig
@@ -378,6 +378,8 @@ pub inline fn getContext(context: *ThreadContext) bool {
}
return true;
}
+
+ return false;
}
/// Invokes detectable illegal behavior when `ok` is `false`.
@@ -619,7 +621,9 @@ pub const StackUnwindOptions = struct {
/// See `writeCurrentStackTrace` to immediately print the trace instead of capturing it.
pub fn captureCurrentStackTrace(options: StackUnwindOptions, addr_buf: []usize) std.builtin.StackTrace {
var context_buf: ThreadContext = undefined;
- var it: StackIterator = .init(options.context, &context_buf);
+ var it = StackIterator.init(options.context, &context_buf) catch {
+ return .{ .index = 0, .instruction_addresses = &.{} };
+ };
defer it.deinit();
if (!it.stratOk(options.allow_unsafe_unwind)) {
return .{ .index = 0, .instruction_addresses = &.{} };
@@ -657,7 +661,14 @@ pub fn writeCurrentStackTrace(options: StackUnwindOptions, writer: *Writer, tty_
},
};
var context_buf: ThreadContext = undefined;
- var it: StackIterator = .init(options.context, &context_buf);
+ var it = StackIterator.init(options.context, &context_buf) catch |err| switch (err) {
+ error.OutOfMemory => {
+ tty_config.setColor(writer, .dim) catch {};
+ try writer.print("Cannot print stack trace: out of memory\n", .{});
+ tty_config.setColor(writer, .reset) catch {};
+ return;
+ },
+ };
defer it.deinit();
if (!it.stratOk(options.allow_unsafe_unwind)) {
tty_config.setColor(writer, .dim) catch {};
@@ -751,14 +762,14 @@ pub fn dumpStackTrace(st: *const std.builtin.StackTrace) void {
const StackIterator = union(enum) {
/// Unwinding using debug info (e.g. DWARF CFI).
- di: if (SelfInfo.supports_unwinding) SelfInfo.DwarfUnwindContext else noreturn,
+ di: if (SelfInfo.supports_unwinding) SelfInfo.UnwindContext else noreturn,
/// Naive frame-pointer-based unwinding. Very simple, but typically unreliable.
fp: usize,
/// It is important that this function is marked `inline` so that it can safely use
/// `@frameAddress` and `getContext` as the caller's stack frame and our own are one
/// and the same.
- inline fn init(context_opt: ?*const ThreadContext, context_buf: *ThreadContext) StackIterator {
+ inline fn init(context_opt: ?*const ThreadContext, context_buf: *ThreadContext) error{OutOfMemory}!StackIterator {
if (builtin.cpu.arch.isSPARC()) {
// Flush all the register windows on stack.
if (builtin.cpu.has(.sparc, .v9)) {
@@ -770,10 +781,10 @@ const StackIterator = union(enum) {
if (context_opt) |context| {
context_buf.* = context.*;
relocateContext(context_buf);
- return .{ .di = .init(context_buf) };
+ return .{ .di = try .init(context_buf, getDebugInfoAllocator()) };
}
if (getContext(context_buf)) {
- return .{ .di = .init(context_buf) };
+ return .{ .di = try .init(context_buf, getDebugInfoAllocator()) };
}
return .{ .fp = @frameAddress() };
}
@@ -816,10 +827,10 @@ const StackIterator = union(enum) {
if (ra == 0) return .end;
return .{ .frame = ra };
} else |err| {
- const bad_pc = unwind_context.pc;
- it.* = .{ .fp = unwind_context.getFp() catch 0 };
+ const pc = unwind_context.pc;
+ it.* = .{ .fp = unwind_context.getFp() };
return .{ .switch_to_fp = .{
- .address = bad_pc,
+ .address = pc,
.err = err,
} };
}