mirror of
https://codeberg.org/ziglang/zig.git
synced 2025-12-06 13:54:21 +00:00
156cd8f678
By my estimation, these changes speed up DWARF unwinding when using the self-hosted x86_64 backend by around 7x. There are two very significant enhancements: we no longer iterate frames which don't fit in the stack trace buffer, and we cache register rules (in a fixed buffer) to avoid re-parsing and evaluating CFI instructions in most cases. Alongside this are a bunch of smaller enhancements, such as pre-caching the result of evaluating the CIE's initial instructions, avoiding re-parsing of CIEs, and big simplifications to the `Dwarf.Unwind.VirtualMachine` logic.
1558 lines
63 KiB
Zig
1558 lines
63 KiB
Zig
const std = @import("std.zig");
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const math = std.math;
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const mem = std.mem;
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const posix = std.posix;
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const fs = std.fs;
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const testing = std.testing;
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const Allocator = mem.Allocator;
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const File = std.fs.File;
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const windows = std.os.windows;
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const Writer = std.Io.Writer;
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const tty = std.Io.tty;
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const builtin = @import("builtin");
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const native_arch = builtin.cpu.arch;
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const native_os = builtin.os.tag;
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const root = @import("root");
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pub const Dwarf = @import("debug/Dwarf.zig");
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pub const Pdb = @import("debug/Pdb.zig");
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pub const ElfFile = @import("debug/ElfFile.zig");
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pub const SelfInfo = @import("debug/SelfInfo.zig");
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pub const Info = @import("debug/Info.zig");
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pub const Coverage = @import("debug/Coverage.zig");
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pub const cpu_context = @import("debug/cpu_context.zig");
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pub const simple_panic = @import("debug/simple_panic.zig");
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pub const no_panic = @import("debug/no_panic.zig");
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/// A fully-featured panic handler namespace which lowers all panics to calls to `panicFn`.
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/// Safety panics will use formatted printing to provide a meaningful error message.
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/// The signature of `panicFn` should match that of `defaultPanic`.
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pub fn FullPanic(comptime panicFn: fn ([]const u8, ?usize) noreturn) type {
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return struct {
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pub const call = panicFn;
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pub fn sentinelMismatch(expected: anytype, found: @TypeOf(expected)) noreturn {
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@branchHint(.cold);
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std.debug.panicExtra(@returnAddress(), "sentinel mismatch: expected {any}, found {any}", .{
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expected, found,
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});
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}
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pub fn unwrapError(err: anyerror) noreturn {
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@branchHint(.cold);
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std.debug.panicExtra(@returnAddress(), "attempt to unwrap error: {s}", .{@errorName(err)});
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}
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pub fn outOfBounds(index: usize, len: usize) noreturn {
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@branchHint(.cold);
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std.debug.panicExtra(@returnAddress(), "index out of bounds: index {d}, len {d}", .{ index, len });
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}
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pub fn startGreaterThanEnd(start: usize, end: usize) noreturn {
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@branchHint(.cold);
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std.debug.panicExtra(@returnAddress(), "start index {d} is larger than end index {d}", .{ start, end });
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}
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pub fn inactiveUnionField(active: anytype, accessed: @TypeOf(active)) noreturn {
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@branchHint(.cold);
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std.debug.panicExtra(@returnAddress(), "access of union field '{s}' while field '{s}' is active", .{
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@tagName(accessed), @tagName(active),
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});
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}
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pub fn sliceCastLenRemainder(src_len: usize) noreturn {
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@branchHint(.cold);
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std.debug.panicExtra(@returnAddress(), "slice length '{d}' does not divide exactly into destination elements", .{src_len});
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}
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pub fn reachedUnreachable() noreturn {
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@branchHint(.cold);
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call("reached unreachable code", @returnAddress());
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}
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pub fn unwrapNull() noreturn {
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@branchHint(.cold);
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call("attempt to use null value", @returnAddress());
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}
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pub fn castToNull() noreturn {
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@branchHint(.cold);
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call("cast causes pointer to be null", @returnAddress());
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}
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pub fn incorrectAlignment() noreturn {
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@branchHint(.cold);
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call("incorrect alignment", @returnAddress());
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}
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pub fn invalidErrorCode() noreturn {
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@branchHint(.cold);
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call("invalid error code", @returnAddress());
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}
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pub fn integerOutOfBounds() noreturn {
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@branchHint(.cold);
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call("integer does not fit in destination type", @returnAddress());
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}
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pub fn integerOverflow() noreturn {
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@branchHint(.cold);
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call("integer overflow", @returnAddress());
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}
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pub fn shlOverflow() noreturn {
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@branchHint(.cold);
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call("left shift overflowed bits", @returnAddress());
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}
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pub fn shrOverflow() noreturn {
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@branchHint(.cold);
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call("right shift overflowed bits", @returnAddress());
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}
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pub fn divideByZero() noreturn {
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@branchHint(.cold);
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call("division by zero", @returnAddress());
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}
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pub fn exactDivisionRemainder() noreturn {
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@branchHint(.cold);
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call("exact division produced remainder", @returnAddress());
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}
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pub fn integerPartOutOfBounds() noreturn {
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@branchHint(.cold);
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call("integer part of floating point value out of bounds", @returnAddress());
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}
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pub fn corruptSwitch() noreturn {
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@branchHint(.cold);
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call("switch on corrupt value", @returnAddress());
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}
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pub fn shiftRhsTooBig() noreturn {
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@branchHint(.cold);
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call("shift amount is greater than the type size", @returnAddress());
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}
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pub fn invalidEnumValue() noreturn {
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@branchHint(.cold);
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call("invalid enum value", @returnAddress());
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}
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pub fn forLenMismatch() noreturn {
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@branchHint(.cold);
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call("for loop over objects with non-equal lengths", @returnAddress());
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}
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pub fn copyLenMismatch() noreturn {
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@branchHint(.cold);
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call("source and destination arguments have non-equal lengths", @returnAddress());
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}
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pub fn memcpyAlias() noreturn {
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@branchHint(.cold);
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call("@memcpy arguments alias", @returnAddress());
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}
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pub fn noreturnReturned() noreturn {
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@branchHint(.cold);
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call("'noreturn' function returned", @returnAddress());
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}
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};
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}
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/// Unresolved source locations can be represented with a single `usize` that
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/// corresponds to a virtual memory address of the program counter. Combined
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/// with debug information, those values can be converted into a resolved
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/// source location, including file, line, and column.
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pub const SourceLocation = struct {
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line: u64,
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column: u64,
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file_name: []const u8,
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pub const invalid: SourceLocation = .{
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.line = 0,
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.column = 0,
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.file_name = &.{},
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};
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};
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pub const Symbol = struct {
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name: ?[]const u8,
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compile_unit_name: ?[]const u8,
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source_location: ?SourceLocation,
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pub const unknown: Symbol = .{
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.name = null,
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.compile_unit_name = null,
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.source_location = null,
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};
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};
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/// Deprecated because it returns the optimization mode of the standard
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/// library, when the caller probably wants to use the optimization mode of
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/// their own module.
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pub const runtime_safety = switch (builtin.mode) {
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.Debug, .ReleaseSafe => true,
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.ReleaseFast, .ReleaseSmall => false,
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};
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/// Whether we can unwind the stack on this target, allowing capturing and/or printing the current
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/// stack trace. It is still legal to call `captureCurrentStackTrace`, `writeCurrentStackTrace`, and
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/// `dumpCurrentStackTrace` if this is `false`; it will just print an error / capture an empty
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/// trace due to missing functionality. This value is just intended as a heuristic to avoid
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/// pointless work e.g. capturing always-empty stack traces.
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pub const sys_can_stack_trace = switch (builtin.cpu.arch) {
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// `@returnAddress()` in LLVM 10 gives
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// "Non-Emscripten WebAssembly hasn't implemented __builtin_return_address".
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// On Emscripten, Zig only supports `@returnAddress()` in debug builds
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// because Emscripten's implementation is very slow.
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.wasm32,
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.wasm64,
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=> native_os == .emscripten and builtin.mode == .Debug,
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// `@returnAddress()` is unsupported in LLVM 21.
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.bpfel,
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.bpfeb,
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=> false,
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else => true,
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};
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/// Allows the caller to freely write to stderr until `unlockStdErr` is called.
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///
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/// During the lock, any `std.Progress` information is cleared from the terminal.
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pub fn lockStdErr() void {
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std.Progress.lockStdErr();
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}
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pub fn unlockStdErr() void {
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std.Progress.unlockStdErr();
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}
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/// Allows the caller to freely write to stderr until `unlockStdErr` is called.
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///
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/// During the lock, any `std.Progress` information is cleared from the terminal.
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///
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/// The lock is recursive, so it is valid for the same thread to call `lockStderrWriter` multiple
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/// times. The primary motivation is that this allows the panic handler to safely dump the stack
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/// trace and panic message even if the mutex was held at the panic site.
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///
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/// The returned `Writer` does not need to be manually flushed: flushing is performed automatically
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/// when the matching `unlockStderrWriter` call occurs.
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pub fn lockStderrWriter(buffer: []u8) *Writer {
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return std.Progress.lockStderrWriter(buffer);
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}
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pub fn unlockStderrWriter() void {
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std.Progress.unlockStderrWriter();
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}
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/// Print to stderr, silently returning on failure. Intended for use in "printf
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/// debugging". Use `std.log` functions for proper logging.
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///
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/// Uses a 64-byte buffer for formatted printing which is flushed before this
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/// function returns.
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pub fn print(comptime fmt: []const u8, args: anytype) void {
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var buffer: [64]u8 = undefined;
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const bw = lockStderrWriter(&buffer);
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defer unlockStderrWriter();
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nosuspend bw.print(fmt, args) catch return;
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}
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/// Marked `inline` to propagate a comptime-known error to callers.
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pub inline fn getSelfDebugInfo() !*SelfInfo {
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if (!SelfInfo.target_supported) return error.UnsupportedTarget;
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const S = struct {
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var self_info: SelfInfo = .init;
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};
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return &S.self_info;
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}
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/// Tries to print a hexadecimal view of the bytes, unbuffered, and ignores any error returned.
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/// Obtains the stderr mutex while dumping.
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pub fn dumpHex(bytes: []const u8) void {
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const bw = lockStderrWriter(&.{});
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defer unlockStderrWriter();
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const ttyconf = tty.detectConfig(.stderr());
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dumpHexFallible(bw, ttyconf, bytes) catch {};
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}
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/// Prints a hexadecimal view of the bytes, returning any error that occurs.
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pub fn dumpHexFallible(bw: *Writer, ttyconf: tty.Config, bytes: []const u8) !void {
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var chunks = mem.window(u8, bytes, 16, 16);
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while (chunks.next()) |window| {
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// 1. Print the address.
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const address = (@intFromPtr(bytes.ptr) + 0x10 * (std.math.divCeil(usize, chunks.index orelse bytes.len, 16) catch unreachable)) - 0x10;
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try ttyconf.setColor(bw, .dim);
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// We print the address in lowercase and the bytes in uppercase hexadecimal to distinguish them more.
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// Also, make sure all lines are aligned by padding the address.
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try bw.print("{x:0>[1]} ", .{ address, @sizeOf(usize) * 2 });
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try ttyconf.setColor(bw, .reset);
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// 2. Print the bytes.
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for (window, 0..) |byte, index| {
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try bw.print("{X:0>2} ", .{byte});
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if (index == 7) try bw.writeByte(' ');
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}
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try bw.writeByte(' ');
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if (window.len < 16) {
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var missing_columns = (16 - window.len) * 3;
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if (window.len < 8) missing_columns += 1;
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try bw.splatByteAll(' ', missing_columns);
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}
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// 3. Print the characters.
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for (window) |byte| {
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if (std.ascii.isPrint(byte)) {
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try bw.writeByte(byte);
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} else {
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// Related: https://github.com/ziglang/zig/issues/7600
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if (ttyconf == .windows_api) {
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try bw.writeByte('.');
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continue;
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}
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// Let's print some common control codes as graphical Unicode symbols.
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// We don't want to do this for all control codes because most control codes apart from
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// the ones that Zig has escape sequences for are likely not very useful to print as symbols.
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switch (byte) {
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'\n' => try bw.writeAll("␊"),
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'\r' => try bw.writeAll("␍"),
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'\t' => try bw.writeAll("␉"),
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else => try bw.writeByte('.'),
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}
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}
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}
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try bw.writeByte('\n');
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}
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}
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test dumpHexFallible {
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const bytes: []const u8 = &.{ 0x00, 0x11, 0x22, 0x33, 0x44, 0x55, 0x66, 0x77, 0x88, 0x99, 0xaa, 0xbb, 0xcc, 0xdd, 0xee, 0xff, 0x01, 0x12, 0x13 };
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var aw: Writer.Allocating = .init(std.testing.allocator);
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defer aw.deinit();
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try dumpHexFallible(&aw.writer, .no_color, bytes);
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const expected = try std.fmt.allocPrint(std.testing.allocator,
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\\{x:0>[2]} 00 11 22 33 44 55 66 77 88 99 AA BB CC DD EE FF .."3DUfw........
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\\{x:0>[2]} 01 12 13 ...
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\\
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, .{
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@intFromPtr(bytes.ptr),
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@intFromPtr(bytes.ptr) + 16,
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@sizeOf(usize) * 2,
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});
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defer std.testing.allocator.free(expected);
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try std.testing.expectEqualStrings(expected, aw.written());
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}
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/// The pointer through which a `cpu_context.Native` is received from callers of stack tracing logic.
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pub const CpuContextPtr = if (cpu_context.Native == noreturn) noreturn else *const cpu_context.Native;
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/// Invokes detectable illegal behavior when `ok` is `false`.
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///
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/// In Debug and ReleaseSafe modes, calls to this function are always
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/// generated, and the `unreachable` statement triggers a panic.
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///
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/// In ReleaseFast and ReleaseSmall modes, calls to this function are optimized
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/// away, and in fact the optimizer is able to use the assertion in its
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/// heuristics.
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///
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/// Inside a test block, it is best to use the `std.testing` module rather than
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/// this function, because this function may not detect a test failure in
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/// ReleaseFast and ReleaseSmall mode. Outside of a test block, this assert
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/// function is the correct function to use.
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pub fn assert(ok: bool) void {
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if (!ok) unreachable; // assertion failure
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}
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/// Invokes detectable illegal behavior when the provided slice is not mapped
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/// or lacks read permissions.
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pub fn assertReadable(slice: []const volatile u8) void {
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if (!runtime_safety) return;
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for (slice) |*byte| _ = byte.*;
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}
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/// Invokes detectable illegal behavior when the provided array is not aligned
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/// to the provided amount.
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pub fn assertAligned(ptr: anytype, comptime alignment: std.mem.Alignment) void {
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const aligned_ptr: *align(alignment.toByteUnits()) const anyopaque = @ptrCast(@alignCast(ptr));
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_ = aligned_ptr;
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}
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|
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/// Equivalent to `@panic` but with a formatted message.
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pub fn panic(comptime format: []const u8, args: anytype) noreturn {
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@branchHint(.cold);
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panicExtra(@returnAddress(), format, args);
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}
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|
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/// Equivalent to `@panic` but with a formatted message and an explicitly provided return address
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/// which will be the first address in the stack trace.
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pub fn panicExtra(
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ret_addr: ?usize,
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comptime format: []const u8,
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args: anytype,
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) noreturn {
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@branchHint(.cold);
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|
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const size = 0x1000;
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const trunc_msg = "(msg truncated)";
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var buf: [size + trunc_msg.len]u8 = undefined;
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var bw: Writer = .fixed(buf[0..size]);
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// a minor annoyance with this is that it will result in the NoSpaceLeft
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|
// error being part of the @panic stack trace (but that error should
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|
// only happen rarely)
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const msg = if (bw.print(format, args)) |_| bw.buffered() else |_| blk: {
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@memcpy(buf[size..], trunc_msg);
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break :blk &buf;
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|
};
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|
std.builtin.panic.call(msg, ret_addr);
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|
}
|
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|
|
/// Non-zero whenever the program triggered a panic.
|
|
/// The counter is incremented/decremented atomically.
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|
var panicking = std.atomic.Value(u8).init(0);
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|
|
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/// Counts how many times the panic handler is invoked by this thread.
|
|
/// This is used to catch and handle panics triggered by the panic handler.
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|
threadlocal var panic_stage: usize = 0;
|
|
|
|
/// For backends that cannot handle the language features depended on by the
|
|
/// default panic handler, we will use a simpler implementation.
|
|
const use_trap_panic = switch (builtin.zig_backend) {
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|
.stage2_aarch64,
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|
.stage2_arm,
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|
.stage2_powerpc,
|
|
.stage2_riscv64,
|
|
.stage2_spirv,
|
|
.stage2_wasm,
|
|
.stage2_x86,
|
|
=> true,
|
|
.stage2_x86_64 => switch (builtin.target.ofmt) {
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|
.elf, .macho => false,
|
|
else => true,
|
|
},
|
|
else => false,
|
|
};
|
|
|
|
/// Dumps a stack trace to standard error, then aborts.
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|
pub fn defaultPanic(
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|
msg: []const u8,
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|
first_trace_addr: ?usize,
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|
) noreturn {
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|
@branchHint(.cold);
|
|
|
|
if (use_trap_panic) @trap();
|
|
|
|
switch (builtin.zig_backend) {
|
|
.stage2_aarch64,
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|
.stage2_arm,
|
|
.stage2_powerpc,
|
|
.stage2_riscv64,
|
|
.stage2_spirv,
|
|
.stage2_wasm,
|
|
.stage2_x86,
|
|
=> @trap(),
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|
.stage2_x86_64 => switch (builtin.target.ofmt) {
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|
.elf, .macho => {},
|
|
else => @trap(),
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|
},
|
|
else => {},
|
|
}
|
|
|
|
switch (builtin.os.tag) {
|
|
.freestanding, .other => {
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|
@trap();
|
|
},
|
|
.uefi => {
|
|
const uefi = std.os.uefi;
|
|
|
|
var utf16_buffer: [1000]u16 = undefined;
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|
const len_minus_3 = std.unicode.utf8ToUtf16Le(&utf16_buffer, msg) catch 0;
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|
utf16_buffer[len_minus_3..][0..3].* = .{ '\r', '\n', 0 };
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|
const len = len_minus_3 + 3;
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|
const exit_msg = utf16_buffer[0 .. len - 1 :0];
|
|
|
|
// Output to both std_err and con_out, as std_err is easier
|
|
// to read in stuff like QEMU at times, but, unlike con_out,
|
|
// isn't visible on actual hardware if directly booted into
|
|
inline for ([_]?*uefi.protocol.SimpleTextOutput{ uefi.system_table.std_err, uefi.system_table.con_out }) |o| {
|
|
if (o) |out| {
|
|
out.setAttribute(.{ .foreground = .red }) catch {};
|
|
_ = out.outputString(exit_msg) catch {};
|
|
out.setAttribute(.{ .foreground = .white }) catch {};
|
|
}
|
|
}
|
|
|
|
if (uefi.system_table.boot_services) |bs| {
|
|
// ExitData buffer must be allocated using boot_services.allocatePool (spec: page 220)
|
|
const exit_data = uefi.raw_pool_allocator.dupeZ(u16, exit_msg) catch @trap();
|
|
bs.exit(uefi.handle, .aborted, exit_data) catch {};
|
|
}
|
|
@trap();
|
|
},
|
|
.cuda, .amdhsa => std.posix.abort(),
|
|
.plan9 => {
|
|
var status: [std.os.plan9.ERRMAX]u8 = undefined;
|
|
const len = @min(msg.len, status.len - 1);
|
|
@memcpy(status[0..len], msg[0..len]);
|
|
status[len] = 0;
|
|
std.os.plan9.exits(status[0..len :0]);
|
|
},
|
|
else => {},
|
|
}
|
|
|
|
if (enable_segfault_handler) {
|
|
// If a segfault happens while panicking, we want it to actually segfault, not trigger
|
|
// the handler.
|
|
resetSegfaultHandler();
|
|
}
|
|
|
|
// There is very similar logic to the following in `handleSegfault`.
|
|
switch (panic_stage) {
|
|
0 => {
|
|
panic_stage = 1;
|
|
_ = panicking.fetchAdd(1, .seq_cst);
|
|
|
|
trace: {
|
|
const tty_config = tty.detectConfig(.stderr());
|
|
|
|
const stderr = lockStderrWriter(&.{});
|
|
defer unlockStderrWriter();
|
|
|
|
if (builtin.single_threaded) {
|
|
stderr.print("panic: ", .{}) catch break :trace;
|
|
} else {
|
|
const current_thread_id = std.Thread.getCurrentId();
|
|
stderr.print("thread {} panic: ", .{current_thread_id}) catch break :trace;
|
|
}
|
|
stderr.print("{s}\n", .{msg}) catch break :trace;
|
|
|
|
if (@errorReturnTrace()) |t| if (t.index > 0) {
|
|
stderr.writeAll("error return context:\n") catch break :trace;
|
|
writeStackTrace(t, stderr, tty_config) catch break :trace;
|
|
stderr.writeAll("\nstack trace:\n") catch break :trace;
|
|
};
|
|
writeCurrentStackTrace(.{
|
|
.first_address = first_trace_addr orelse @returnAddress(),
|
|
.allow_unsafe_unwind = true, // we're crashing anyway, give it our all!
|
|
}, stderr, tty_config) catch break :trace;
|
|
}
|
|
|
|
waitForOtherThreadToFinishPanicking();
|
|
},
|
|
1 => {
|
|
panic_stage = 2;
|
|
// A panic happened while trying to print a previous panic message.
|
|
// We're still holding the mutex but that's fine as we're going to
|
|
// call abort().
|
|
fs.File.stderr().writeAll("aborting due to recursive panic\n") catch {};
|
|
},
|
|
else => {}, // Panicked while printing the recursive panic message.
|
|
}
|
|
|
|
posix.abort();
|
|
}
|
|
|
|
/// Must be called only after adding 1 to `panicking`. There are three callsites.
|
|
fn waitForOtherThreadToFinishPanicking() void {
|
|
if (panicking.fetchSub(1, .seq_cst) != 1) {
|
|
// Another thread is panicking, wait for the last one to finish
|
|
// and call abort()
|
|
if (builtin.single_threaded) unreachable;
|
|
|
|
// Sleep forever without hammering the CPU
|
|
var futex = std.atomic.Value(u32).init(0);
|
|
while (true) std.Thread.Futex.wait(&futex, 0);
|
|
unreachable;
|
|
}
|
|
}
|
|
|
|
pub const StackUnwindOptions = struct {
|
|
/// If not `null`, we will ignore all frames up until this return address. This is typically
|
|
/// used to omit intermediate handling code (for instance, a panic handler and its machinery)
|
|
/// from stack traces.
|
|
first_address: ?usize = null,
|
|
/// If not `null`, we will unwind from this `cpu_context.Native` instead of the current top of
|
|
/// the stack. The main use case here is printing stack traces from signal handlers, where the
|
|
/// kernel provides a `*const cpu_context.Native` of the state before the signal.
|
|
context: ?CpuContextPtr = null,
|
|
/// If `true`, stack unwinding strategies which may cause crashes are used as a last resort.
|
|
/// If `false`, only known-safe mechanisms will be attempted.
|
|
allow_unsafe_unwind: bool = false,
|
|
};
|
|
|
|
/// Capture and return the current stack trace. The returned `StackTrace` stores its addresses in
|
|
/// the given buffer, so `addr_buf` must have a lifetime at least equal to the `StackTrace`.
|
|
///
|
|
/// See `writeCurrentStackTrace` to immediately print the trace instead of capturing it.
|
|
pub fn captureCurrentStackTrace(options: StackUnwindOptions, addr_buf: []usize) std.builtin.StackTrace {
|
|
const empty_trace: std.builtin.StackTrace = .{ .index = 0, .instruction_addresses = &.{} };
|
|
if (!std.options.allow_stack_tracing) return empty_trace;
|
|
var it = StackIterator.init(options.context) catch return empty_trace;
|
|
defer it.deinit();
|
|
if (!it.stratOk(options.allow_unsafe_unwind)) return empty_trace;
|
|
var total_frames: usize = 0;
|
|
var index: usize = 0;
|
|
var wait_for = options.first_address;
|
|
// Ideally, we would iterate the whole stack so that the `index` in the returned trace was
|
|
// indicative of how many frames were skipped. However, this has a significant runtime cost
|
|
// in some cases, so at least for now, we don't do that.
|
|
while (index < addr_buf.len) switch (it.next()) {
|
|
.switch_to_fp => if (!it.stratOk(options.allow_unsafe_unwind)) break,
|
|
.end => break,
|
|
.frame => |ret_addr| {
|
|
if (total_frames > 10_000) {
|
|
// Limit the number of frames in case of (e.g.) broken debug information which is
|
|
// getting unwinding stuck in a loop.
|
|
break;
|
|
}
|
|
total_frames += 1;
|
|
if (wait_for) |target| {
|
|
if (ret_addr != target) continue;
|
|
wait_for = null;
|
|
}
|
|
addr_buf[index] = ret_addr;
|
|
index += 1;
|
|
},
|
|
};
|
|
return .{
|
|
.index = index,
|
|
.instruction_addresses = addr_buf[0..index],
|
|
};
|
|
}
|
|
/// Write the current stack trace to `writer`, annotated with source locations.
|
|
///
|
|
/// See `captureCurrentStackTrace` to capture the trace addresses into a buffer instead of printing.
|
|
pub fn writeCurrentStackTrace(options: StackUnwindOptions, writer: *Writer, tty_config: tty.Config) Writer.Error!void {
|
|
if (!std.options.allow_stack_tracing) {
|
|
tty_config.setColor(writer, .dim) catch {};
|
|
try writer.print("Cannot print stack trace: stack tracing is disabled\n", .{});
|
|
tty_config.setColor(writer, .reset) catch {};
|
|
return;
|
|
}
|
|
const di_gpa = getDebugInfoAllocator();
|
|
const di = getSelfDebugInfo() catch |err| switch (err) {
|
|
error.UnsupportedTarget => {
|
|
tty_config.setColor(writer, .dim) catch {};
|
|
try writer.print("Cannot print stack trace: debug info unavailable for target\n", .{});
|
|
tty_config.setColor(writer, .reset) catch {};
|
|
return;
|
|
},
|
|
};
|
|
var it = StackIterator.init(options.context) catch |err| switch (err) {
|
|
error.CannotUnwindFromContext => {
|
|
tty_config.setColor(writer, .dim) catch {};
|
|
try writer.print("Cannot print stack trace: context unwind unavailable for target\n", .{});
|
|
tty_config.setColor(writer, .reset) catch {};
|
|
return;
|
|
},
|
|
};
|
|
defer it.deinit();
|
|
if (!it.stratOk(options.allow_unsafe_unwind)) {
|
|
tty_config.setColor(writer, .dim) catch {};
|
|
try writer.print("Cannot print stack trace: safe unwind unavailable for target\n", .{});
|
|
tty_config.setColor(writer, .reset) catch {};
|
|
return;
|
|
}
|
|
var total_frames: usize = 0;
|
|
var wait_for = options.first_address;
|
|
var printed_any_frame = false;
|
|
while (true) switch (it.next()) {
|
|
.switch_to_fp => |unwind_error| {
|
|
if (StackIterator.fp_unwind_is_safe) continue; // no need to even warn
|
|
const module_name = di.getModuleNameForAddress(di_gpa, unwind_error.address) catch "???";
|
|
const caption: []const u8 = switch (unwind_error.err) {
|
|
error.MissingDebugInfo => "unwind info unavailable",
|
|
error.InvalidDebugInfo => "unwind info invalid",
|
|
error.UnsupportedDebugInfo => "unwind info unsupported",
|
|
error.ReadFailed => "filesystem error",
|
|
error.OutOfMemory => "out of memory",
|
|
error.Unexpected => "unexpected error",
|
|
};
|
|
if (it.stratOk(options.allow_unsafe_unwind)) {
|
|
tty_config.setColor(writer, .dim) catch {};
|
|
try writer.print(
|
|
"Unwind error at address `{s}:0x{x}` ({s}), remaining frames may be incorrect\n",
|
|
.{ module_name, unwind_error.address, caption },
|
|
);
|
|
tty_config.setColor(writer, .reset) catch {};
|
|
} else {
|
|
tty_config.setColor(writer, .dim) catch {};
|
|
try writer.print(
|
|
"Unwind error at address `{s}:0x{x}` ({s}), stopping trace early\n",
|
|
.{ module_name, unwind_error.address, caption },
|
|
);
|
|
tty_config.setColor(writer, .reset) catch {};
|
|
return;
|
|
}
|
|
},
|
|
.end => break,
|
|
.frame => |ret_addr| {
|
|
if (total_frames > 10_000) {
|
|
tty_config.setColor(writer, .dim) catch {};
|
|
try writer.print(
|
|
"Stopping trace after {d} frames (large frame count may indicate broken debug info)\n",
|
|
.{total_frames},
|
|
);
|
|
tty_config.setColor(writer, .reset) catch {};
|
|
return;
|
|
}
|
|
total_frames += 1;
|
|
if (wait_for) |target| {
|
|
if (ret_addr != target) continue;
|
|
wait_for = null;
|
|
}
|
|
// `ret_addr` is the return address, which is *after* the function call.
|
|
// Subtract 1 to get an address *in* the function call for a better source location.
|
|
try printSourceAtAddress(di_gpa, di, writer, ret_addr -| 1, tty_config);
|
|
printed_any_frame = true;
|
|
},
|
|
};
|
|
if (!printed_any_frame) return writer.writeAll("(empty stack trace)\n");
|
|
}
|
|
/// A thin wrapper around `writeCurrentStackTrace` which writes to stderr and ignores write errors.
|
|
pub fn dumpCurrentStackTrace(options: StackUnwindOptions) void {
|
|
const tty_config = tty.detectConfig(.stderr());
|
|
const stderr = lockStderrWriter(&.{});
|
|
defer unlockStderrWriter();
|
|
writeCurrentStackTrace(.{
|
|
.first_address = a: {
|
|
if (options.first_address) |a| break :a a;
|
|
if (options.context != null) break :a null;
|
|
break :a @returnAddress(); // don't include this frame in the trace
|
|
},
|
|
.context = options.context,
|
|
.allow_unsafe_unwind = options.allow_unsafe_unwind,
|
|
}, stderr, tty_config) catch |err| switch (err) {
|
|
error.WriteFailed => {},
|
|
};
|
|
}
|
|
|
|
/// Write a previously captured stack trace to `writer`, annotated with source locations.
|
|
pub fn writeStackTrace(st: *const std.builtin.StackTrace, writer: *Writer, tty_config: tty.Config) Writer.Error!void {
|
|
if (!std.options.allow_stack_tracing) {
|
|
tty_config.setColor(writer, .dim) catch {};
|
|
try writer.print("Cannot print stack trace: stack tracing is disabled\n", .{});
|
|
tty_config.setColor(writer, .reset) catch {};
|
|
return;
|
|
}
|
|
// Fetch `st.index` straight away. Aside from avoiding redundant loads, this prevents issues if
|
|
// `st` is `@errorReturnTrace()` and errors are encountered while writing the stack trace.
|
|
const n_frames = st.index;
|
|
if (n_frames == 0) return writer.writeAll("(empty stack trace)\n");
|
|
const di_gpa = getDebugInfoAllocator();
|
|
const di = getSelfDebugInfo() catch |err| switch (err) {
|
|
error.UnsupportedTarget => {
|
|
tty_config.setColor(writer, .dim) catch {};
|
|
try writer.print("Cannot print stack trace: debug info unavailable for target\n\n", .{});
|
|
tty_config.setColor(writer, .reset) catch {};
|
|
return;
|
|
},
|
|
};
|
|
const captured_frames = @min(n_frames, st.instruction_addresses.len);
|
|
for (st.instruction_addresses[0..captured_frames]) |ret_addr| {
|
|
// `ret_addr` is the return address, which is *after* the function call.
|
|
// Subtract 1 to get an address *in* the function call for a better source location.
|
|
try printSourceAtAddress(di_gpa, di, writer, ret_addr -| 1, tty_config);
|
|
}
|
|
if (n_frames > captured_frames) {
|
|
tty_config.setColor(writer, .bold) catch {};
|
|
try writer.print("({d} additional stack frames skipped...)\n", .{n_frames - captured_frames});
|
|
tty_config.setColor(writer, .reset) catch {};
|
|
}
|
|
}
|
|
/// A thin wrapper around `writeStackTrace` which writes to stderr and ignores write errors.
|
|
pub fn dumpStackTrace(st: *const std.builtin.StackTrace) void {
|
|
const tty_config = tty.detectConfig(.stderr());
|
|
const stderr = lockStderrWriter(&.{});
|
|
defer unlockStderrWriter();
|
|
writeStackTrace(st, stderr, tty_config) catch |err| switch (err) {
|
|
error.WriteFailed => {},
|
|
};
|
|
}
|
|
|
|
const StackIterator = union(enum) {
|
|
/// Unwinding using debug info (e.g. DWARF CFI).
|
|
di: if (SelfInfo.supports_unwinding) SelfInfo.UnwindContext else noreturn,
|
|
/// We will first report the *current* PC of this `UnwindContext`, then we will switch to `di`.
|
|
di_first: 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 `cpu_context.Native.current` as the caller's stack frame and
|
|
/// our own are one and the same.
|
|
inline fn init(opt_context_ptr: ?CpuContextPtr) error{CannotUnwindFromContext}!StackIterator {
|
|
if (builtin.cpu.arch.isSPARC()) {
|
|
// Flush all the register windows on stack.
|
|
if (builtin.cpu.has(.sparc, .v9)) {
|
|
asm volatile ("flushw" ::: .{ .memory = true });
|
|
} else {
|
|
asm volatile ("ta 3" ::: .{ .memory = true }); // ST_FLUSH_WINDOWS
|
|
}
|
|
}
|
|
if (opt_context_ptr) |context_ptr| {
|
|
if (!SelfInfo.supports_unwinding) return error.CannotUnwindFromContext;
|
|
// Use `di_first` here so we report the PC in the context before unwinding any further.
|
|
return .{ .di_first = .init(context_ptr) };
|
|
}
|
|
// Workaround the C backend being unable to use inline assembly on MSVC by disabling the
|
|
// call to `current`. This effectively constrains stack trace collection and dumping to FP
|
|
// unwinding when building with CBE for MSVC.
|
|
if (!(builtin.zig_backend == .stage2_c and builtin.target.abi == .msvc) and
|
|
SelfInfo.supports_unwinding and
|
|
cpu_context.Native != noreturn)
|
|
{
|
|
// We don't need `di_first` here, because our PC is in `std.debug`; we're only interested
|
|
// in our caller's frame and above.
|
|
return .{ .di = .init(&.current()) };
|
|
}
|
|
return .{ .fp = @frameAddress() };
|
|
}
|
|
fn deinit(si: *StackIterator) void {
|
|
switch (si.*) {
|
|
.fp => {},
|
|
.di, .di_first => |*unwind_context| unwind_context.deinit(getDebugInfoAllocator()),
|
|
}
|
|
}
|
|
|
|
/// On aarch64-macos, Apple mandate that the frame pointer is always used.
|
|
/// TODO: are there any other architectures with guarantees like this?
|
|
const fp_unwind_is_safe = builtin.cpu.arch == .aarch64 and builtin.os.tag.isDarwin();
|
|
|
|
/// Whether the current unwind strategy is allowed given `allow_unsafe`.
|
|
fn stratOk(it: *const StackIterator, allow_unsafe: bool) bool {
|
|
return switch (it.*) {
|
|
.di, .di_first => true,
|
|
// If we omitted frame pointers from *this* compilation, FP unwinding would crash
|
|
// immediately regardless of anything. But FPs could also be omitted from a different
|
|
// linked object, so it's not guaranteed to be safe, unless the target specifically
|
|
// requires it.
|
|
.fp => !builtin.omit_frame_pointer and (fp_unwind_is_safe or allow_unsafe),
|
|
};
|
|
}
|
|
|
|
const Result = union(enum) {
|
|
/// A stack frame has been found; this is the corresponding return address.
|
|
frame: usize,
|
|
/// The end of the stack has been reached.
|
|
end,
|
|
/// We were using `SelfInfo.UnwindInfo`, but are now switching to FP unwinding due to this error.
|
|
switch_to_fp: struct {
|
|
address: usize,
|
|
err: SelfInfo.Error,
|
|
},
|
|
};
|
|
|
|
fn next(it: *StackIterator) Result {
|
|
switch (it.*) {
|
|
.di_first => |unwind_context| {
|
|
const first_pc = unwind_context.pc;
|
|
if (first_pc == 0) return .end;
|
|
it.* = .{ .di = unwind_context };
|
|
// The caller expects *return* addresses, where they will subtract 1 to find the address of the call.
|
|
// However, we have the actual current PC, which should not be adjusted. Compensate by adding 1.
|
|
return .{ .frame = first_pc +| 1 };
|
|
},
|
|
.di => |*unwind_context| {
|
|
const di = getSelfDebugInfo() catch unreachable;
|
|
const di_gpa = getDebugInfoAllocator();
|
|
const ret_addr = di.unwindFrame(di_gpa, unwind_context) catch |err| {
|
|
const pc = unwind_context.pc;
|
|
it.* = .{ .fp = unwind_context.getFp() };
|
|
return .{ .switch_to_fp = .{
|
|
.address = pc,
|
|
.err = err,
|
|
} };
|
|
};
|
|
if (ret_addr <= 1) return .end;
|
|
return .{ .frame = ret_addr };
|
|
},
|
|
.fp => |fp| {
|
|
if (fp == 0) return .end; // we reached the "sentinel" base pointer
|
|
|
|
const bp_addr = applyOffset(fp, bp_offset) orelse return .end;
|
|
const ra_addr = applyOffset(fp, ra_offset) orelse return .end;
|
|
|
|
if (bp_addr == 0 or !mem.isAligned(bp_addr, @alignOf(usize)) or
|
|
ra_addr == 0 or !mem.isAligned(ra_addr, @alignOf(usize)))
|
|
{
|
|
// This isn't valid, but it most likely indicates end of stack.
|
|
return .end;
|
|
}
|
|
|
|
const bp_ptr: *const usize = @ptrFromInt(bp_addr);
|
|
const ra_ptr: *const usize = @ptrFromInt(ra_addr);
|
|
const bp = applyOffset(bp_ptr.*, bp_bias) orelse return .end;
|
|
|
|
// The stack grows downards, so `bp > fp` should always hold. If it doesn't, this
|
|
// frame is invalid, so we'll treat it as though it we reached end of stack. The
|
|
// exception is address 0, which is a graceful end-of-stack signal, in which case
|
|
// *this* return address is valid and the *next* iteration will be the last.
|
|
if (bp != 0 and bp <= fp) return .end;
|
|
|
|
it.fp = bp;
|
|
const ra = stripInstructionPtrAuthCode(ra_ptr.*);
|
|
if (ra <= 1) return .end;
|
|
return .{ .frame = ra };
|
|
},
|
|
}
|
|
}
|
|
|
|
/// Offset of the saved base pointer (previous frame pointer) wrt the frame pointer.
|
|
const bp_offset = off: {
|
|
// On RISC-V the frame pointer points to the top of the saved register
|
|
// area, on pretty much every other architecture it points to the stack
|
|
// slot where the previous frame pointer is saved.
|
|
if (native_arch.isRISCV()) break :off -2 * @sizeOf(usize);
|
|
// On SPARC the previous frame pointer is stored at 14 slots past %fp+BIAS.
|
|
if (native_arch.isSPARC()) break :off 14 * @sizeOf(usize);
|
|
break :off 0;
|
|
};
|
|
|
|
/// Offset of the saved return address wrt the frame pointer.
|
|
const ra_offset = off: {
|
|
if (native_arch == .powerpc64le) break :off 2 * @sizeOf(usize);
|
|
break :off @sizeOf(usize);
|
|
};
|
|
|
|
/// Value to add to a base pointer after loading it from the stack. Yes, SPARC really does this.
|
|
const bp_bias = bias: {
|
|
if (native_arch.isSPARC()) break :bias 2047;
|
|
break :bias 0;
|
|
};
|
|
|
|
fn applyOffset(addr: usize, comptime off: comptime_int) ?usize {
|
|
if (off >= 0) return math.add(usize, addr, off) catch return null;
|
|
return math.sub(usize, addr, -off) catch return null;
|
|
}
|
|
};
|
|
|
|
/// Some platforms use pointer authentication: the upper bits of instruction pointers contain a
|
|
/// signature. This function clears those signature bits to make the pointer directly usable.
|
|
pub inline fn stripInstructionPtrAuthCode(ptr: usize) usize {
|
|
if (native_arch.isAARCH64()) {
|
|
// `hint 0x07` maps to `xpaclri` (or `nop` if the hardware doesn't support it)
|
|
// The save / restore is because `xpaclri` operates on x30 (LR)
|
|
return asm (
|
|
\\mov x16, x30
|
|
\\mov x30, x15
|
|
\\hint 0x07
|
|
\\mov x15, x30
|
|
\\mov x30, x16
|
|
: [ret] "={x15}" (-> usize),
|
|
: [ptr] "{x15}" (ptr),
|
|
: .{ .x16 = true });
|
|
}
|
|
|
|
return ptr;
|
|
}
|
|
|
|
fn printSourceAtAddress(gpa: Allocator, debug_info: *SelfInfo, writer: *Writer, address: usize, tty_config: tty.Config) Writer.Error!void {
|
|
const symbol: Symbol = debug_info.getSymbolAtAddress(gpa, address) catch |err| switch (err) {
|
|
error.MissingDebugInfo,
|
|
error.UnsupportedDebugInfo,
|
|
error.InvalidDebugInfo,
|
|
=> .unknown,
|
|
error.ReadFailed, error.Unexpected => s: {
|
|
tty_config.setColor(writer, .dim) catch {};
|
|
try writer.print("Failed to read debug info from filesystem, trace may be incomplete\n\n", .{});
|
|
tty_config.setColor(writer, .reset) catch {};
|
|
break :s .unknown;
|
|
},
|
|
error.OutOfMemory => s: {
|
|
tty_config.setColor(writer, .dim) catch {};
|
|
try writer.print("Ran out of memory loading debug info, trace may be incomplete\n\n", .{});
|
|
tty_config.setColor(writer, .reset) catch {};
|
|
break :s .unknown;
|
|
},
|
|
};
|
|
defer if (symbol.source_location) |sl| gpa.free(sl.file_name);
|
|
return printLineInfo(
|
|
writer,
|
|
symbol.source_location,
|
|
address,
|
|
symbol.name orelse "???",
|
|
symbol.compile_unit_name orelse debug_info.getModuleNameForAddress(gpa, address) catch "???",
|
|
tty_config,
|
|
);
|
|
}
|
|
fn printLineInfo(
|
|
writer: *Writer,
|
|
source_location: ?SourceLocation,
|
|
address: usize,
|
|
symbol_name: []const u8,
|
|
compile_unit_name: []const u8,
|
|
tty_config: tty.Config,
|
|
) Writer.Error!void {
|
|
nosuspend {
|
|
tty_config.setColor(writer, .bold) catch {};
|
|
|
|
if (source_location) |*sl| {
|
|
try writer.print("{s}:{d}:{d}", .{ sl.file_name, sl.line, sl.column });
|
|
} else {
|
|
try writer.writeAll("???:?:?");
|
|
}
|
|
|
|
tty_config.setColor(writer, .reset) catch {};
|
|
try writer.writeAll(": ");
|
|
tty_config.setColor(writer, .dim) catch {};
|
|
try writer.print("0x{x} in {s} ({s})", .{ address, symbol_name, compile_unit_name });
|
|
tty_config.setColor(writer, .reset) catch {};
|
|
try writer.writeAll("\n");
|
|
|
|
// Show the matching source code line if possible
|
|
if (source_location) |sl| {
|
|
if (printLineFromFile(writer, sl)) {
|
|
if (sl.column > 0) {
|
|
// The caret already takes one char
|
|
const space_needed = @as(usize, @intCast(sl.column - 1));
|
|
|
|
try writer.splatByteAll(' ', space_needed);
|
|
tty_config.setColor(writer, .green) catch {};
|
|
try writer.writeAll("^");
|
|
tty_config.setColor(writer, .reset) catch {};
|
|
}
|
|
try writer.writeAll("\n");
|
|
} else |_| {
|
|
// Ignore all errors; it's a better UX to just print the source location without the
|
|
// corresponding line number. The user can always open the source file themselves.
|
|
}
|
|
}
|
|
}
|
|
}
|
|
fn printLineFromFile(writer: *Writer, source_location: SourceLocation) !void {
|
|
// Allow overriding the target-agnostic source line printing logic by exposing `root.debug.printLineFromFile`.
|
|
if (@hasDecl(root, "debug") and @hasDecl(root.debug, "printLineFromFile")) {
|
|
return root.debug.printLineFromFile(writer, source_location);
|
|
}
|
|
|
|
// Need this to always block even in async I/O mode, because this could potentially
|
|
// be called from e.g. the event loop code crashing.
|
|
var f = try fs.cwd().openFile(source_location.file_name, .{});
|
|
defer f.close();
|
|
// TODO fstat and make sure that the file has the correct size
|
|
|
|
var buf: [4096]u8 = undefined;
|
|
var amt_read = try f.read(buf[0..]);
|
|
const line_start = seek: {
|
|
var current_line_start: usize = 0;
|
|
var next_line: usize = 1;
|
|
while (next_line != source_location.line) {
|
|
const slice = buf[current_line_start..amt_read];
|
|
if (mem.indexOfScalar(u8, slice, '\n')) |pos| {
|
|
next_line += 1;
|
|
if (pos == slice.len - 1) {
|
|
amt_read = try f.read(buf[0..]);
|
|
current_line_start = 0;
|
|
} else current_line_start += pos + 1;
|
|
} else if (amt_read < buf.len) {
|
|
return error.EndOfFile;
|
|
} else {
|
|
amt_read = try f.read(buf[0..]);
|
|
current_line_start = 0;
|
|
}
|
|
}
|
|
break :seek current_line_start;
|
|
};
|
|
const slice = buf[line_start..amt_read];
|
|
if (mem.indexOfScalar(u8, slice, '\n')) |pos| {
|
|
const line = slice[0 .. pos + 1];
|
|
mem.replaceScalar(u8, line, '\t', ' ');
|
|
return writer.writeAll(line);
|
|
} else { // Line is the last inside the buffer, and requires another read to find delimiter. Alternatively the file ends.
|
|
mem.replaceScalar(u8, slice, '\t', ' ');
|
|
try writer.writeAll(slice);
|
|
while (amt_read == buf.len) {
|
|
amt_read = try f.read(buf[0..]);
|
|
if (mem.indexOfScalar(u8, buf[0..amt_read], '\n')) |pos| {
|
|
const line = buf[0 .. pos + 1];
|
|
mem.replaceScalar(u8, line, '\t', ' ');
|
|
return writer.writeAll(line);
|
|
} else {
|
|
const line = buf[0..amt_read];
|
|
mem.replaceScalar(u8, line, '\t', ' ');
|
|
try writer.writeAll(line);
|
|
}
|
|
}
|
|
// Make sure printing last line of file inserts extra newline
|
|
try writer.writeByte('\n');
|
|
}
|
|
}
|
|
|
|
test printLineFromFile {
|
|
var aw: Writer.Allocating = .init(std.testing.allocator);
|
|
defer aw.deinit();
|
|
const output_stream = &aw.writer;
|
|
|
|
const allocator = std.testing.allocator;
|
|
const join = std.fs.path.join;
|
|
const expectError = std.testing.expectError;
|
|
const expectEqualStrings = std.testing.expectEqualStrings;
|
|
|
|
var test_dir = std.testing.tmpDir(.{});
|
|
defer test_dir.cleanup();
|
|
// Relies on testing.tmpDir internals which is not ideal, but SourceLocation requires paths.
|
|
const test_dir_path = try join(allocator, &.{ ".zig-cache", "tmp", test_dir.sub_path[0..] });
|
|
defer allocator.free(test_dir_path);
|
|
|
|
// Cases
|
|
{
|
|
const path = try join(allocator, &.{ test_dir_path, "one_line.zig" });
|
|
defer allocator.free(path);
|
|
try test_dir.dir.writeFile(.{ .sub_path = "one_line.zig", .data = "no new lines in this file, but one is printed anyway" });
|
|
|
|
try expectError(error.EndOfFile, printLineFromFile(output_stream, .{ .file_name = path, .line = 2, .column = 0 }));
|
|
|
|
try printLineFromFile(output_stream, .{ .file_name = path, .line = 1, .column = 0 });
|
|
try expectEqualStrings("no new lines in this file, but one is printed anyway\n", aw.written());
|
|
aw.clearRetainingCapacity();
|
|
}
|
|
{
|
|
const path = try fs.path.join(allocator, &.{ test_dir_path, "three_lines.zig" });
|
|
defer allocator.free(path);
|
|
try test_dir.dir.writeFile(.{
|
|
.sub_path = "three_lines.zig",
|
|
.data =
|
|
\\1
|
|
\\2
|
|
\\3
|
|
,
|
|
});
|
|
|
|
try printLineFromFile(output_stream, .{ .file_name = path, .line = 1, .column = 0 });
|
|
try expectEqualStrings("1\n", aw.written());
|
|
aw.clearRetainingCapacity();
|
|
|
|
try printLineFromFile(output_stream, .{ .file_name = path, .line = 3, .column = 0 });
|
|
try expectEqualStrings("3\n", aw.written());
|
|
aw.clearRetainingCapacity();
|
|
}
|
|
{
|
|
const file = try test_dir.dir.createFile("line_overlaps_page_boundary.zig", .{});
|
|
defer file.close();
|
|
const path = try fs.path.join(allocator, &.{ test_dir_path, "line_overlaps_page_boundary.zig" });
|
|
defer allocator.free(path);
|
|
|
|
const overlap = 10;
|
|
var buf: [16]u8 = undefined;
|
|
var file_writer = file.writer(&buf);
|
|
const writer = &file_writer.interface;
|
|
try writer.splatByteAll('a', std.heap.page_size_min - overlap);
|
|
try writer.writeByte('\n');
|
|
try writer.splatByteAll('a', overlap);
|
|
try writer.flush();
|
|
|
|
try printLineFromFile(output_stream, .{ .file_name = path, .line = 2, .column = 0 });
|
|
try expectEqualStrings(("a" ** overlap) ++ "\n", aw.written());
|
|
aw.clearRetainingCapacity();
|
|
}
|
|
{
|
|
const file = try test_dir.dir.createFile("file_ends_on_page_boundary.zig", .{});
|
|
defer file.close();
|
|
const path = try fs.path.join(allocator, &.{ test_dir_path, "file_ends_on_page_boundary.zig" });
|
|
defer allocator.free(path);
|
|
|
|
var file_writer = file.writer(&.{});
|
|
const writer = &file_writer.interface;
|
|
try writer.splatByteAll('a', std.heap.page_size_max);
|
|
|
|
try printLineFromFile(output_stream, .{ .file_name = path, .line = 1, .column = 0 });
|
|
try expectEqualStrings(("a" ** std.heap.page_size_max) ++ "\n", aw.written());
|
|
aw.clearRetainingCapacity();
|
|
}
|
|
{
|
|
const file = try test_dir.dir.createFile("very_long_first_line_spanning_multiple_pages.zig", .{});
|
|
defer file.close();
|
|
const path = try fs.path.join(allocator, &.{ test_dir_path, "very_long_first_line_spanning_multiple_pages.zig" });
|
|
defer allocator.free(path);
|
|
|
|
var file_writer = file.writer(&.{});
|
|
const writer = &file_writer.interface;
|
|
try writer.splatByteAll('a', 3 * std.heap.page_size_max);
|
|
|
|
try expectError(error.EndOfFile, printLineFromFile(output_stream, .{ .file_name = path, .line = 2, .column = 0 }));
|
|
|
|
try printLineFromFile(output_stream, .{ .file_name = path, .line = 1, .column = 0 });
|
|
try expectEqualStrings(("a" ** (3 * std.heap.page_size_max)) ++ "\n", aw.written());
|
|
aw.clearRetainingCapacity();
|
|
|
|
try writer.writeAll("a\na");
|
|
|
|
try printLineFromFile(output_stream, .{ .file_name = path, .line = 1, .column = 0 });
|
|
try expectEqualStrings(("a" ** (3 * std.heap.page_size_max)) ++ "a\n", aw.written());
|
|
aw.clearRetainingCapacity();
|
|
|
|
try printLineFromFile(output_stream, .{ .file_name = path, .line = 2, .column = 0 });
|
|
try expectEqualStrings("a\n", aw.written());
|
|
aw.clearRetainingCapacity();
|
|
}
|
|
{
|
|
const file = try test_dir.dir.createFile("file_of_newlines.zig", .{});
|
|
defer file.close();
|
|
const path = try fs.path.join(allocator, &.{ test_dir_path, "file_of_newlines.zig" });
|
|
defer allocator.free(path);
|
|
|
|
var file_writer = file.writer(&.{});
|
|
const writer = &file_writer.interface;
|
|
const real_file_start = 3 * std.heap.page_size_min;
|
|
try writer.splatByteAll('\n', real_file_start);
|
|
try writer.writeAll("abc\ndef");
|
|
|
|
try printLineFromFile(output_stream, .{ .file_name = path, .line = real_file_start + 1, .column = 0 });
|
|
try expectEqualStrings("abc\n", aw.written());
|
|
aw.clearRetainingCapacity();
|
|
|
|
try printLineFromFile(output_stream, .{ .file_name = path, .line = real_file_start + 2, .column = 0 });
|
|
try expectEqualStrings("def\n", aw.written());
|
|
aw.clearRetainingCapacity();
|
|
}
|
|
}
|
|
|
|
/// The returned allocator should be thread-safe if the compilation is multi-threaded, because
|
|
/// multiple threads could capture and/or print stack traces simultaneously.
|
|
fn getDebugInfoAllocator() Allocator {
|
|
// Allow overriding the debug info allocator by exposing `root.debug.getDebugInfoAllocator`.
|
|
if (@hasDecl(root, "debug") and @hasDecl(root.debug, "getDebugInfoAllocator")) {
|
|
return root.debug.getDebugInfoAllocator();
|
|
}
|
|
// Otherwise, use a global arena backed by the page allocator
|
|
const S = struct {
|
|
var arena: std.heap.ArenaAllocator = .init(std.heap.page_allocator);
|
|
var ts_arena: std.heap.ThreadSafeAllocator = .{ .child_allocator = arena.allocator() };
|
|
};
|
|
return S.ts_arena.allocator();
|
|
}
|
|
|
|
/// Whether or not the current target can print useful debug information when a segfault occurs.
|
|
pub const have_segfault_handling_support = switch (native_os) {
|
|
.linux,
|
|
.macos,
|
|
.netbsd,
|
|
.solaris,
|
|
.illumos,
|
|
.windows,
|
|
.freebsd,
|
|
.openbsd,
|
|
=> true,
|
|
|
|
else => false,
|
|
};
|
|
|
|
const enable_segfault_handler = std.options.enable_segfault_handler;
|
|
pub const default_enable_segfault_handler = runtime_safety and have_segfault_handling_support;
|
|
|
|
pub fn maybeEnableSegfaultHandler() void {
|
|
if (enable_segfault_handler) {
|
|
attachSegfaultHandler();
|
|
}
|
|
}
|
|
|
|
var windows_segfault_handle: ?windows.HANDLE = null;
|
|
|
|
pub fn updateSegfaultHandler(act: ?*const posix.Sigaction) void {
|
|
posix.sigaction(posix.SIG.SEGV, act, null);
|
|
posix.sigaction(posix.SIG.ILL, act, null);
|
|
posix.sigaction(posix.SIG.BUS, act, null);
|
|
posix.sigaction(posix.SIG.FPE, act, null);
|
|
}
|
|
|
|
/// Attaches a global handler for several signals which, when triggered, prints output to stderr
|
|
/// similar to the default panic handler, with a message containing the type of signal and a stack
|
|
/// trace if possible. This implementation does not just call the panic handler, because unwinding
|
|
/// the stack (for a stack trace) when a signal is received requires special target-specific logic.
|
|
///
|
|
/// The signals for which a handler is installed are:
|
|
/// * SIGSEGV (segmentation fault)
|
|
/// * SIGILL (illegal instruction)
|
|
/// * SIGBUS (bus error)
|
|
/// * SIGFPE (arithmetic exception)
|
|
pub fn attachSegfaultHandler() void {
|
|
if (!have_segfault_handling_support) {
|
|
@compileError("segfault handler not supported for this target");
|
|
}
|
|
if (native_os == .windows) {
|
|
windows_segfault_handle = windows.kernel32.AddVectoredExceptionHandler(0, handleSegfaultWindows);
|
|
return;
|
|
}
|
|
const act = posix.Sigaction{
|
|
.handler = .{ .sigaction = handleSegfaultPosix },
|
|
.mask = posix.sigemptyset(),
|
|
.flags = (posix.SA.SIGINFO | posix.SA.RESTART | posix.SA.RESETHAND),
|
|
};
|
|
updateSegfaultHandler(&act);
|
|
}
|
|
|
|
fn resetSegfaultHandler() void {
|
|
if (native_os == .windows) {
|
|
if (windows_segfault_handle) |handle| {
|
|
assert(windows.kernel32.RemoveVectoredExceptionHandler(handle) != 0);
|
|
windows_segfault_handle = null;
|
|
}
|
|
return;
|
|
}
|
|
const act = posix.Sigaction{
|
|
.handler = .{ .handler = posix.SIG.DFL },
|
|
.mask = posix.sigemptyset(),
|
|
.flags = 0,
|
|
};
|
|
updateSegfaultHandler(&act);
|
|
}
|
|
|
|
fn handleSegfaultPosix(sig: i32, info: *const posix.siginfo_t, ctx_ptr: ?*anyopaque) callconv(.c) noreturn {
|
|
if (use_trap_panic) @trap();
|
|
const addr: ?usize, const name: []const u8 = info: {
|
|
if (native_os == .linux and native_arch == .x86_64) {
|
|
// x86_64 doesn't have a full 64-bit virtual address space.
|
|
// Addresses outside of that address space are non-canonical
|
|
// and the CPU won't provide the faulting address to us.
|
|
// This happens when accessing memory addresses such as 0xaaaaaaaaaaaaaaaa
|
|
// but can also happen when no addressable memory is involved;
|
|
// for example when reading/writing model-specific registers
|
|
// by executing `rdmsr` or `wrmsr` in user-space (unprivileged mode).
|
|
const SI_KERNEL = 0x80;
|
|
if (sig == posix.SIG.SEGV and info.code == SI_KERNEL) {
|
|
break :info .{ null, "General protection exception" };
|
|
}
|
|
}
|
|
const addr: usize = switch (native_os) {
|
|
.linux => @intFromPtr(info.fields.sigfault.addr),
|
|
.freebsd, .macos => @intFromPtr(info.addr),
|
|
.netbsd => @intFromPtr(info.info.reason.fault.addr),
|
|
.openbsd => @intFromPtr(info.data.fault.addr),
|
|
.solaris, .illumos => @intFromPtr(info.reason.fault.addr),
|
|
else => comptime unreachable,
|
|
};
|
|
const name = switch (sig) {
|
|
posix.SIG.SEGV => "Segmentation fault",
|
|
posix.SIG.ILL => "Illegal instruction",
|
|
posix.SIG.BUS => "Bus error",
|
|
posix.SIG.FPE => "Arithmetic exception",
|
|
else => unreachable,
|
|
};
|
|
break :info .{ addr, name };
|
|
};
|
|
const opt_cpu_context: ?cpu_context.Native = cpu_context.fromPosixSignalContext(ctx_ptr);
|
|
handleSegfault(addr, name, if (opt_cpu_context) |*ctx| ctx else null);
|
|
}
|
|
|
|
fn handleSegfaultWindows(info: *windows.EXCEPTION_POINTERS) callconv(.winapi) c_long {
|
|
if (use_trap_panic) @trap();
|
|
const name: []const u8, const addr: ?usize = switch (info.ExceptionRecord.ExceptionCode) {
|
|
windows.EXCEPTION_DATATYPE_MISALIGNMENT => .{ "Unaligned memory access", null },
|
|
windows.EXCEPTION_ACCESS_VIOLATION => .{ "Segmentation fault", info.ExceptionRecord.ExceptionInformation[1] },
|
|
windows.EXCEPTION_ILLEGAL_INSTRUCTION => .{ "Illegal instruction", info.ContextRecord.getRegs().ip },
|
|
windows.EXCEPTION_STACK_OVERFLOW => .{ "Stack overflow", null },
|
|
else => return windows.EXCEPTION_CONTINUE_SEARCH,
|
|
};
|
|
handleSegfault(addr, name, &cpu_context.fromWindowsContext(info.ContextRecord));
|
|
}
|
|
|
|
fn handleSegfault(addr: ?usize, name: []const u8, opt_ctx: ?CpuContextPtr) noreturn {
|
|
// Allow overriding the target-agnostic segfault handler by exposing `root.debug.handleSegfault`.
|
|
if (@hasDecl(root, "debug") and @hasDecl(root.debug, "handleSegfault")) {
|
|
return root.debug.handleSegfault(addr, name, opt_ctx);
|
|
}
|
|
return defaultHandleSegfault(addr, name, opt_ctx);
|
|
}
|
|
|
|
pub fn defaultHandleSegfault(addr: ?usize, name: []const u8, opt_ctx: ?CpuContextPtr) noreturn {
|
|
// There is very similar logic to the following in `defaultPanic`.
|
|
switch (panic_stage) {
|
|
0 => {
|
|
panic_stage = 1;
|
|
_ = panicking.fetchAdd(1, .seq_cst);
|
|
|
|
trace: {
|
|
const tty_config = tty.detectConfig(.stderr());
|
|
|
|
const stderr = lockStderrWriter(&.{});
|
|
defer unlockStderrWriter();
|
|
|
|
if (addr) |a| {
|
|
stderr.print("{s} at address 0x{x}\n", .{ name, a }) catch break :trace;
|
|
} else {
|
|
stderr.print("{s} (no address available)\n", .{name}) catch break :trace;
|
|
}
|
|
if (opt_ctx) |context| {
|
|
writeCurrentStackTrace(.{
|
|
.context = context,
|
|
.allow_unsafe_unwind = true, // we're crashing anyway, give it our all!
|
|
}, stderr, tty_config) catch break :trace;
|
|
}
|
|
}
|
|
},
|
|
1 => {
|
|
panic_stage = 2;
|
|
// A segfault happened while trying to print a previous panic message.
|
|
// We're still holding the mutex but that's fine as we're going to
|
|
// call abort().
|
|
fs.File.stderr().writeAll("aborting due to recursive panic\n") catch {};
|
|
},
|
|
else => {}, // Panicked while printing the recursive panic message.
|
|
}
|
|
|
|
// We cannot allow the signal handler to return because when it runs the original instruction
|
|
// again, the memory may be mapped and undefined behavior would occur rather than repeating
|
|
// the segfault. So we simply abort here.
|
|
posix.abort();
|
|
}
|
|
|
|
pub fn dumpStackPointerAddr(prefix: []const u8) void {
|
|
const sp = asm (""
|
|
: [argc] "={rsp}" (-> usize),
|
|
);
|
|
print("{s} sp = 0x{x}\n", .{ prefix, sp });
|
|
}
|
|
|
|
test "manage resources correctly" {
|
|
if (!SelfInfo.target_supported) return error.SkipZigTest;
|
|
const S = struct {
|
|
noinline fn showMyTrace() usize {
|
|
return @returnAddress();
|
|
}
|
|
};
|
|
const gpa = std.testing.allocator;
|
|
var discarding: std.Io.Writer.Discarding = .init(&.{});
|
|
var di: SelfInfo = .init;
|
|
defer di.deinit(gpa);
|
|
try printSourceAtAddress(
|
|
gpa,
|
|
&di,
|
|
&discarding.writer,
|
|
S.showMyTrace(),
|
|
tty.detectConfig(.stderr()),
|
|
);
|
|
}
|
|
|
|
/// This API helps you track where a value originated and where it was mutated,
|
|
/// or any other points of interest.
|
|
/// In debug mode, it adds a small size penalty (104 bytes on 64-bit architectures)
|
|
/// to the aggregate that you add it to.
|
|
/// In release mode, it is size 0 and all methods are no-ops.
|
|
/// This is a pre-made type with default settings.
|
|
/// For more advanced usage, see `ConfigurableTrace`.
|
|
pub const Trace = ConfigurableTrace(2, 4, builtin.mode == .Debug);
|
|
|
|
pub fn ConfigurableTrace(comptime size: usize, comptime stack_frame_count: usize, comptime is_enabled: bool) type {
|
|
return struct {
|
|
addrs: [actual_size][stack_frame_count]usize,
|
|
notes: [actual_size][]const u8,
|
|
index: Index,
|
|
|
|
const actual_size = if (enabled) size else 0;
|
|
const Index = if (enabled) usize else u0;
|
|
|
|
pub const init: @This() = .{
|
|
.addrs = undefined,
|
|
.notes = undefined,
|
|
.index = 0,
|
|
};
|
|
|
|
pub const enabled = is_enabled;
|
|
|
|
pub const add = if (enabled) addNoInline else addNoOp;
|
|
|
|
pub noinline fn addNoInline(t: *@This(), note: []const u8) void {
|
|
comptime assert(enabled);
|
|
return addAddr(t, @returnAddress(), note);
|
|
}
|
|
|
|
pub inline fn addNoOp(t: *@This(), note: []const u8) void {
|
|
_ = t;
|
|
_ = note;
|
|
comptime assert(!enabled);
|
|
}
|
|
|
|
pub fn addAddr(t: *@This(), addr: usize, note: []const u8) void {
|
|
if (!enabled) return;
|
|
|
|
if (t.index < size) {
|
|
t.notes[t.index] = note;
|
|
const addrs = &t.addrs[t.index];
|
|
const st = captureCurrentStackTrace(.{ .first_address = addr }, addrs);
|
|
if (st.index < addrs.len) {
|
|
@memset(addrs[st.index..], 0); // zero unused frames to indicate end of trace
|
|
}
|
|
}
|
|
// Keep counting even if the end is reached so that the
|
|
// user can find out how much more size they need.
|
|
t.index += 1;
|
|
}
|
|
|
|
pub fn dump(t: @This()) void {
|
|
if (!enabled) return;
|
|
|
|
const tty_config = tty.detectConfig(.stderr());
|
|
const stderr = lockStderrWriter(&.{});
|
|
defer unlockStderrWriter();
|
|
const end = @min(t.index, size);
|
|
for (t.addrs[0..end], 0..) |frames_array, i| {
|
|
stderr.print("{s}:\n", .{t.notes[i]}) catch return;
|
|
var frames_array_mutable = frames_array;
|
|
const frames = mem.sliceTo(frames_array_mutable[0..], 0);
|
|
const stack_trace: std.builtin.StackTrace = .{
|
|
.index = frames.len,
|
|
.instruction_addresses = frames,
|
|
};
|
|
writeStackTrace(&stack_trace, stderr, tty_config) catch return;
|
|
}
|
|
if (t.index > end) {
|
|
stderr.print("{d} more traces not shown; consider increasing trace size\n", .{
|
|
t.index - end,
|
|
}) catch return;
|
|
}
|
|
}
|
|
|
|
pub fn format(
|
|
t: @This(),
|
|
comptime fmt: []const u8,
|
|
options: std.fmt.Options,
|
|
writer: *Writer,
|
|
) !void {
|
|
if (fmt.len != 0) std.fmt.invalidFmtError(fmt, t);
|
|
_ = options;
|
|
if (enabled) {
|
|
try writer.writeAll("\n");
|
|
t.dump();
|
|
try writer.writeAll("\n");
|
|
} else {
|
|
return writer.writeAll("(value tracing disabled)");
|
|
}
|
|
}
|
|
};
|
|
}
|
|
|
|
pub const SafetyLock = struct {
|
|
state: State = if (runtime_safety) .unlocked else .unknown,
|
|
|
|
pub const State = if (runtime_safety) enum { unlocked, locked } else enum { unknown };
|
|
|
|
pub fn lock(l: *SafetyLock) void {
|
|
if (!runtime_safety) return;
|
|
assert(l.state == .unlocked);
|
|
l.state = .locked;
|
|
}
|
|
|
|
pub fn unlock(l: *SafetyLock) void {
|
|
if (!runtime_safety) return;
|
|
assert(l.state == .locked);
|
|
l.state = .unlocked;
|
|
}
|
|
|
|
pub fn assertUnlocked(l: SafetyLock) void {
|
|
if (!runtime_safety) return;
|
|
assert(l.state == .unlocked);
|
|
}
|
|
|
|
pub fn assertLocked(l: SafetyLock) void {
|
|
if (!runtime_safety) return;
|
|
assert(l.state == .locked);
|
|
}
|
|
};
|
|
|
|
test SafetyLock {
|
|
var safety_lock: SafetyLock = .{};
|
|
safety_lock.assertUnlocked();
|
|
safety_lock.lock();
|
|
safety_lock.assertLocked();
|
|
safety_lock.unlock();
|
|
safety_lock.assertUnlocked();
|
|
}
|
|
|
|
/// Detect whether the program is being executed in the Valgrind virtual machine.
|
|
///
|
|
/// When Valgrind integrations are disabled, this returns comptime-known false.
|
|
/// Otherwise, the result is runtime-known.
|
|
pub inline fn inValgrind() bool {
|
|
if (@inComptime()) return false;
|
|
if (!builtin.valgrind_support) return false;
|
|
return std.valgrind.runningOnValgrind() > 0;
|
|
}
|
|
|
|
test {
|
|
_ = &Dwarf;
|
|
_ = &Pdb;
|
|
_ = &SelfInfo;
|
|
_ = &dumpHex;
|
|
}
|