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zig/lib/std/debug.zig

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const std = @import("std.zig");
const builtin = std.builtin;
const math = std.math;
const mem = std.mem;
const io = std.io;
const os = std.os;
const fs = std.fs;
const process = std.process;
const elf = std.elf;
const DW = std.dwarf;
const macho = std.macho;
const coff = std.coff;
const pdb = std.pdb;
const ArrayList = std.ArrayList;
const root = @import("root");
const maxInt = std.math.maxInt;
const File = std.fs.File;
const windows = std.os.windows;
pub const leb = @import("debug/leb128.zig");
pub const global_allocator = @compileError("Please switch to std.testing.allocator.");
pub const failing_allocator = @compileError("Please switch to std.testing.failing_allocator.");
pub const runtime_safety = switch (builtin.mode) {
.Debug, .ReleaseSafe => true,
.ReleaseFast, .ReleaseSmall => false,
};
const Module = struct {
mod_info: pdb.ModInfo,
module_name: []u8,
obj_file_name: []u8,
populated: bool,
symbols: []u8,
subsect_info: []u8,
checksum_offset: ?usize,
};
pub const LineInfo = struct {
line: u64,
column: u64,
file_name: []const u8,
allocator: ?*mem.Allocator,
fn deinit(self: LineInfo) void {
const allocator = self.allocator orelse return;
allocator.free(self.file_name);
}
};
/// Tries to write to stderr, unbuffered, and ignores any error returned.
/// Does not append a newline.
var stderr_file: File = undefined;
var stderr_file_out_stream: File.OutStream = undefined;
var stderr_stream: ?*File.OutStream = null;
var stderr_mutex = std.Mutex.init();
pub fn warn(comptime fmt: []const u8, args: var) void {
const held = stderr_mutex.acquire();
defer held.release();
const stderr = getStderrStream();
noasync stderr.print(fmt, args) catch return;
}
pub fn getStderrStream() *File.OutStream {
if (stderr_stream) |st| {
return st;
} else {
stderr_file = io.getStdErr();
stderr_file_out_stream = stderr_file.outStream();
const st = &stderr_file_out_stream;
stderr_stream = st;
return st;
}
}
pub fn getStderrMutex() *std.Mutex {
return &stderr_mutex;
}
/// TODO multithreaded awareness
var self_debug_info: ?DebugInfo = null;
pub fn getSelfDebugInfo() !*DebugInfo {
if (self_debug_info) |*info| {
return info;
} else {
self_debug_info = try openSelfDebugInfo(getDebugInfoAllocator());
return &self_debug_info.?;
}
}
pub fn detectTTYConfig() TTY.Config {
var bytes: [128]u8 = undefined;
const allocator = &std.heap.FixedBufferAllocator.init(bytes[0..]).allocator;
if (process.getEnvVarOwned(allocator, "ZIG_DEBUG_COLOR")) |_| {
return .escape_codes;
} else |_| {
if (stderr_file.supportsAnsiEscapeCodes()) {
return .escape_codes;
} else if (builtin.os.tag == .windows and stderr_file.isTty()) {
return .windows_api;
} else {
return .no_color;
}
}
}
/// Tries to print the current stack trace to stderr, unbuffered, and ignores any error returned.
/// TODO multithreaded awareness
pub fn dumpCurrentStackTrace(start_addr: ?usize) void {
const stderr = getStderrStream();
if (builtin.strip_debug_info) {
noasync stderr.print("Unable to dump stack trace: debug info stripped\n", .{}) catch return;
return;
}
const debug_info = getSelfDebugInfo() catch |err| {
noasync stderr.print("Unable to dump stack trace: Unable to open debug info: {}\n", .{@errorName(err)}) catch return;
return;
};
writeCurrentStackTrace(stderr, debug_info, detectTTYConfig(), start_addr) catch |err| {
noasync stderr.print("Unable to dump stack trace: {}\n", .{@errorName(err)}) catch return;
return;
};
}
/// Tries to print the stack trace starting from the supplied base pointer to stderr,
/// unbuffered, and ignores any error returned.
/// TODO multithreaded awareness
pub fn dumpStackTraceFromBase(bp: usize, ip: usize) void {
const stderr = getStderrStream();
if (builtin.strip_debug_info) {
noasync stderr.print("Unable to dump stack trace: debug info stripped\n", .{}) catch return;
return;
}
const debug_info = getSelfDebugInfo() catch |err| {
noasync stderr.print("Unable to dump stack trace: Unable to open debug info: {}\n", .{@errorName(err)}) catch return;
return;
};
const tty_config = detectTTYConfig();
printSourceAtAddress(debug_info, stderr, ip, tty_config) catch return;
var it = StackIterator.init(null, bp);
while (it.next()) |return_address| {
printSourceAtAddress(debug_info, stderr, return_address - 1, tty_config) catch return;
}
}
/// Returns a slice with the same pointer as addresses, with a potentially smaller len.
/// On Windows, when first_address is not null, we ask for at least 32 stack frames,
/// and then try to find the first address. If addresses.len is more than 32, we
/// capture that many stack frames exactly, and then look for the first address,
/// chopping off the irrelevant frames and shifting so that the returned addresses pointer
/// equals the passed in addresses pointer.
pub fn captureStackTrace(first_address: ?usize, stack_trace: *builtin.StackTrace) void {
if (builtin.os.tag == .windows) {
const addrs = stack_trace.instruction_addresses;
const u32_addrs_len = @intCast(u32, addrs.len);
const first_addr = first_address orelse {
stack_trace.index = windows.ntdll.RtlCaptureStackBackTrace(
0,
u32_addrs_len,
@ptrCast(**c_void, addrs.ptr),
null,
);
return;
};
var addr_buf_stack: [32]usize = undefined;
const addr_buf = if (addr_buf_stack.len > addrs.len) addr_buf_stack[0..] else addrs;
const n = windows.ntdll.RtlCaptureStackBackTrace(0, u32_addrs_len, @ptrCast(**c_void, addr_buf.ptr), null);
const first_index = for (addr_buf[0..n]) |addr, i| {
if (addr == first_addr) {
break i;
}
} else {
stack_trace.index = 0;
return;
};
const slice = addr_buf[first_index..n];
// We use a for loop here because slice and addrs may alias.
for (slice) |addr, i| {
addrs[i] = addr;
}
stack_trace.index = slice.len;
} else {
var it = StackIterator.init(first_address, null);
for (stack_trace.instruction_addresses) |*addr, i| {
addr.* = it.next() orelse {
stack_trace.index = i;
return;
};
}
stack_trace.index = stack_trace.instruction_addresses.len;
}
}
/// Tries to print a stack trace to stderr, unbuffered, and ignores any error returned.
/// TODO multithreaded awareness
pub fn dumpStackTrace(stack_trace: builtin.StackTrace) void {
const stderr = getStderrStream();
if (builtin.strip_debug_info) {
noasync stderr.print("Unable to dump stack trace: debug info stripped\n", .{}) catch return;
return;
}
const debug_info = getSelfDebugInfo() catch |err| {
noasync stderr.print("Unable to dump stack trace: Unable to open debug info: {}\n", .{@errorName(err)}) catch return;
return;
};
writeStackTrace(stack_trace, stderr, getDebugInfoAllocator(), debug_info, detectTTYConfig()) catch |err| {
noasync stderr.print("Unable to dump stack trace: {}\n", .{@errorName(err)}) catch return;
return;
};
}
/// This function invokes undefined behavior when `ok` is `false`.
/// In Debug and ReleaseSafe modes, calls to this function are always
/// generated, and the `unreachable` statement triggers a panic.
/// In ReleaseFast and ReleaseSmall modes, calls to this function are
/// optimized away, and in fact the optimizer is able to use the assertion
/// in its heuristics.
/// Inside a test block, it is best to use the `std.testing` module rather
/// than this function, because this function may not detect a test failure
/// in ReleaseFast and ReleaseSmall mode. Outside of a test block, this assert
/// function is the correct function to use.
pub fn assert(ok: bool) void {
if (!ok) unreachable; // assertion failure
}
pub fn panic(comptime format: []const u8, args: var) noreturn {
@setCold(true);
// TODO: remove conditional once wasi / LLVM defines __builtin_return_address
const first_trace_addr = if (builtin.os.tag == .wasi) null else @returnAddress();
panicExtra(null, first_trace_addr, format, args);
}
/// Non-zero whenever the program triggered a panic.
/// The counter is incremented/decremented atomically.
var panicking: u8 = 0;
// Locked to avoid interleaving panic messages from multiple threads.
var panic_mutex = std.Mutex.init();
/// 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.
threadlocal var panic_stage: usize = 0;
pub fn panicExtra(trace: ?*const builtin.StackTrace, first_trace_addr: ?usize, comptime format: []const u8, args: var) noreturn {
@setCold(true);
if (enable_segfault_handler) {
// If a segfault happens while panicking, we want it to actually segfault, not trigger
// the handler.
resetSegfaultHandler();
}
switch (panic_stage) {
0 => {
panic_stage = 1;
_ = @atomicRmw(u8, &panicking, .Add, 1, .SeqCst);
// Make sure to release the mutex when done
{
const held = panic_mutex.acquire();
defer held.release();
const stderr = getStderrStream();
noasync stderr.print(format ++ "\n", args) catch os.abort();
if (trace) |t| {
dumpStackTrace(t.*);
}
dumpCurrentStackTrace(first_trace_addr);
}
if (@atomicRmw(u8, &panicking, .Sub, 1, .SeqCst) != 1) {
// Another thread is panicking, wait for the last one to finish
// and call abort()
// Sleep forever without hammering the CPU
var event = std.ResetEvent.init();
event.wait();
unreachable;
}
},
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()
const stderr = getStderrStream();
noasync stderr.print("Panicked during a panic. Aborting.\n", .{}) catch os.abort();
},
else => {
// Panicked while printing "Panicked during a panic."
},
}
os.abort();
}
const RED = "\x1b[31;1m";
const GREEN = "\x1b[32;1m";
const CYAN = "\x1b[36;1m";
const WHITE = "\x1b[37;1m";
const DIM = "\x1b[2m";
const RESET = "\x1b[0m";
pub fn writeStackTrace(
stack_trace: builtin.StackTrace,
out_stream: var,
allocator: *mem.Allocator,
debug_info: *DebugInfo,
tty_config: TTY.Config,
) !void {
if (builtin.strip_debug_info) return error.MissingDebugInfo;
var frame_index: usize = 0;
var frames_left: usize = std.math.min(stack_trace.index, stack_trace.instruction_addresses.len);
while (frames_left != 0) : ({
frames_left -= 1;
frame_index = (frame_index + 1) % stack_trace.instruction_addresses.len;
}) {
const return_address = stack_trace.instruction_addresses[frame_index];
try printSourceAtAddress(debug_info, out_stream, return_address - 1, tty_config);
}
}
pub const StackIterator = struct {
// Skip every frame before this address is found
first_address: ?usize,
// Last known value of the frame pointer register
fp: usize,
pub fn init(first_address: ?usize, fp: ?usize) StackIterator {
return StackIterator{
.first_address = first_address,
.fp = fp orelse @frameAddress(),
};
}
// On some architectures such as x86 the frame pointer is the address where
// the previous fp is stored, while on some other architectures such as
// RISC-V it points to the "top" of the frame, just above where the previous
// fp and the return address are stored.
const fp_offset = if (builtin.arch.isRISCV())
2 * @sizeOf(usize)
else
0;
fn next(self: *StackIterator) ?usize {
var address = self.next_internal() orelse return null;
if (self.first_address) |first_address| {
while (address != first_address) {
address = self.next_internal() orelse return null;
}
self.first_address = null;
}
return address;
}
fn next_internal(self: *StackIterator) ?usize {
const fp = math.sub(usize, self.fp, fp_offset) catch return null;
// Sanity check
if (fp == 0 or !mem.isAligned(fp, @alignOf(usize)))
return null;
const new_fp = @intToPtr(*const usize, fp).*;
// Sanity check: the stack grows down thus all the parent frames must be
// be at addresses that are greater (or equal) than the previous one.
// A zero frame pointer often signals this is the last frame, that case
// is gracefully handled by the next call to next_internal
if (new_fp != 0 and new_fp < self.fp)
return null;
const new_pc = @intToPtr(*const usize, fp + @sizeOf(usize)).*;
self.fp = new_fp;
return new_pc;
}
};
pub fn writeCurrentStackTrace(
out_stream: var,
debug_info: *DebugInfo,
tty_config: TTY.Config,
start_addr: ?usize,
) !void {
if (builtin.os.tag == .windows) {
return writeCurrentStackTraceWindows(out_stream, debug_info, tty_config, start_addr);
}
var it = StackIterator.init(start_addr, null);
while (it.next()) |return_address| {
try printSourceAtAddress(debug_info, out_stream, return_address - 1, tty_config);
}
}
pub fn writeCurrentStackTraceWindows(
out_stream: var,
debug_info: *DebugInfo,
tty_config: TTY.Config,
start_addr: ?usize,
) !void {
var addr_buf: [1024]usize = undefined;
const n = windows.ntdll.RtlCaptureStackBackTrace(0, addr_buf.len, @ptrCast(**c_void, &addr_buf), null);
const addrs = addr_buf[0..n];
var start_i: usize = if (start_addr) |saddr| blk: {
for (addrs) |addr, i| {
if (addr == saddr) break :blk i;
}
return;
} else 0;
for (addrs[start_i..]) |addr| {
try printSourceAtAddress(debug_info, out_stream, addr - 1, tty_config);
}
}
pub const TTY = struct {
pub const Color = enum {
Red,
Green,
Cyan,
White,
Dim,
Bold,
Reset,
};
pub const Config = enum {
no_color,
escape_codes,
// TODO give this a payload of file handle
windows_api,
fn setColor(conf: Config, out_stream: var, color: Color) void {
noasync switch (conf) {
.no_color => return,
.escape_codes => switch (color) {
.Red => out_stream.writeAll(RED) catch return,
.Green => out_stream.writeAll(GREEN) catch return,
.Cyan => out_stream.writeAll(CYAN) catch return,
.White, .Bold => out_stream.writeAll(WHITE) catch return,
.Dim => out_stream.writeAll(DIM) catch return,
.Reset => out_stream.writeAll(RESET) catch return,
},
.windows_api => if (builtin.os.tag == .windows) {
const S = struct {
var attrs: windows.WORD = undefined;
var init_attrs = false;
};
if (!S.init_attrs) {
S.init_attrs = true;
var info: windows.CONSOLE_SCREEN_BUFFER_INFO = undefined;
// TODO handle error
_ = windows.kernel32.GetConsoleScreenBufferInfo(stderr_file.handle, &info);
S.attrs = info.wAttributes;
}
// TODO handle errors
switch (color) {
.Red => {
_ = windows.SetConsoleTextAttribute(stderr_file.handle, windows.FOREGROUND_RED | windows.FOREGROUND_INTENSITY) catch {};
},
.Green => {
_ = windows.SetConsoleTextAttribute(stderr_file.handle, windows.FOREGROUND_GREEN | windows.FOREGROUND_INTENSITY) catch {};
},
.Cyan => {
_ = windows.SetConsoleTextAttribute(stderr_file.handle, windows.FOREGROUND_GREEN | windows.FOREGROUND_BLUE | windows.FOREGROUND_INTENSITY) catch {};
},
.White, .Bold => {
_ = windows.SetConsoleTextAttribute(stderr_file.handle, windows.FOREGROUND_RED | windows.FOREGROUND_GREEN | windows.FOREGROUND_BLUE | windows.FOREGROUND_INTENSITY) catch {};
},
.Dim => {
_ = windows.SetConsoleTextAttribute(stderr_file.handle, windows.FOREGROUND_INTENSITY) catch {};
},
.Reset => {
_ = windows.SetConsoleTextAttribute(stderr_file.handle, S.attrs) catch {};
},
}
} else {
unreachable;
},
};
}
};
};
/// TODO resources https://github.com/ziglang/zig/issues/4353
fn populateModule(di: *ModuleDebugInfo, mod: *Module) !void {
if (mod.populated)
return;
const allocator = getDebugInfoAllocator();
// At most one can be non-zero.
if (mod.mod_info.C11ByteSize != 0 and mod.mod_info.C13ByteSize != 0)
return error.InvalidDebugInfo;
if (mod.mod_info.C13ByteSize == 0)
return;
const modi = di.pdb.getStreamById(mod.mod_info.ModuleSymStream) orelse return error.MissingDebugInfo;
const signature = try modi.inStream().readIntLittle(u32);
if (signature != 4)
return error.InvalidDebugInfo;
mod.symbols = try allocator.alloc(u8, mod.mod_info.SymByteSize - 4);
try modi.inStream().readNoEof(mod.symbols);
mod.subsect_info = try allocator.alloc(u8, mod.mod_info.C13ByteSize);
try modi.inStream().readNoEof(mod.subsect_info);
var sect_offset: usize = 0;
var skip_len: usize = undefined;
while (sect_offset != mod.subsect_info.len) : (sect_offset += skip_len) {
const subsect_hdr = @ptrCast(*pdb.DebugSubsectionHeader, &mod.subsect_info[sect_offset]);
skip_len = subsect_hdr.Length;
sect_offset += @sizeOf(pdb.DebugSubsectionHeader);
switch (subsect_hdr.Kind) {
.FileChecksums => {
mod.checksum_offset = sect_offset;
break;
},
else => {},
}
if (sect_offset > mod.subsect_info.len)
return error.InvalidDebugInfo;
}
mod.populated = true;
}
fn machoSearchSymbols(symbols: []const MachoSymbol, address: usize) ?*const MachoSymbol {
var min: usize = 0;
var max: usize = symbols.len - 1; // Exclude sentinel.
while (min < max) {
const mid = min + (max - min) / 2;
const curr = &symbols[mid];
const next = &symbols[mid + 1];
if (address >= next.address()) {
min = mid + 1;
} else if (address < curr.address()) {
max = mid;
} else {
return curr;
}
}
return null;
}
/// TODO resources https://github.com/ziglang/zig/issues/4353
pub fn printSourceAtAddress(debug_info: *DebugInfo, out_stream: var, address: usize, tty_config: TTY.Config) !void {
const module = debug_info.getModuleForAddress(address) catch |err| switch (err) {
error.MissingDebugInfo, error.InvalidDebugInfo => {
return printLineInfo(
out_stream,
null,
address,
"???",
"???",
tty_config,
printLineFromFileAnyOs,
);
},
else => return err,
};
const symbol_info = try module.getSymbolAtAddress(address);
defer symbol_info.deinit();
return printLineInfo(
out_stream,
symbol_info.line_info,
address,
symbol_info.symbol_name,
symbol_info.compile_unit_name,
tty_config,
printLineFromFileAnyOs,
);
}
fn printLineInfo(
out_stream: var,
line_info: ?LineInfo,
address: usize,
symbol_name: []const u8,
compile_unit_name: []const u8,
tty_config: TTY.Config,
comptime printLineFromFile: var,
) !void {
noasync {
tty_config.setColor(out_stream, .White);
if (line_info) |*li| {
try out_stream.print("{}:{}:{}", .{ li.file_name, li.line, li.column });
} else {
try out_stream.writeAll("???:?:?");
}
tty_config.setColor(out_stream, .Reset);
try out_stream.writeAll(": ");
tty_config.setColor(out_stream, .Dim);
try out_stream.print("0x{x} in {} ({})", .{ address, symbol_name, compile_unit_name });
tty_config.setColor(out_stream, .Reset);
try out_stream.writeAll("\n");
// Show the matching source code line if possible
if (line_info) |li| {
if (printLineFromFile(out_stream, li)) {
if (li.column > 0) {
// The caret already takes one char
const space_needed = @intCast(usize, li.column - 1);
try out_stream.writeByteNTimes(' ', space_needed);
tty_config.setColor(out_stream, .Green);
try out_stream.writeAll("^");
tty_config.setColor(out_stream, .Reset);
}
try out_stream.writeAll("\n");
} else |err| switch (err) {
error.EndOfFile, error.FileNotFound => {},
error.BadPathName => {},
else => return err,
}
}
}
}
// TODO use this
pub const OpenSelfDebugInfoError = error{
MissingDebugInfo,
OutOfMemory,
UnsupportedOperatingSystem,
};
/// TODO resources https://github.com/ziglang/zig/issues/4353
pub fn openSelfDebugInfo(allocator: *mem.Allocator) anyerror!DebugInfo {
noasync {
if (builtin.strip_debug_info)
return error.MissingDebugInfo;
if (@hasDecl(root, "os") and @hasDecl(root.os, "debug") and @hasDecl(root.os.debug, "openSelfDebugInfo")) {
return root.os.debug.openSelfDebugInfo(allocator);
}
switch (builtin.os.tag) {
.linux,
.freebsd,
.macosx,
.windows,
=> return DebugInfo.init(allocator),
else => @compileError("openSelfDebugInfo unsupported for this platform"),
}
}
}
/// TODO resources https://github.com/ziglang/zig/issues/4353
fn openCoffDebugInfo(allocator: *mem.Allocator, coff_file_path: [:0]const u16) !ModuleDebugInfo {
const coff_file = try std.fs.openFileAbsoluteW(coff_file_path.ptr, .{});
errdefer coff_file.close();
const coff_obj = try allocator.create(coff.Coff);
coff_obj.* = coff.Coff.init(allocator, coff_file);
var di = ModuleDebugInfo{
.base_address = undefined,
.coff = coff_obj,
.pdb = undefined,
.sect_contribs = undefined,
.modules = undefined,
};
try di.coff.loadHeader();
var path_buf: [windows.MAX_PATH]u8 = undefined;
const len = try di.coff.getPdbPath(path_buf[0..]);
const raw_path = path_buf[0..len];
const path = try fs.path.resolve(allocator, &[_][]const u8{raw_path});
try di.pdb.openFile(di.coff, path);
var pdb_stream = di.pdb.getStream(pdb.StreamType.Pdb) orelse return error.InvalidDebugInfo;
const version = try pdb_stream.inStream().readIntLittle(u32);
const signature = try pdb_stream.inStream().readIntLittle(u32);
const age = try pdb_stream.inStream().readIntLittle(u32);
var guid: [16]u8 = undefined;
try pdb_stream.inStream().readNoEof(&guid);
if (version != 20000404) // VC70, only value observed by LLVM team
return error.UnknownPDBVersion;
if (!mem.eql(u8, &di.coff.guid, &guid) or di.coff.age != age)
return error.PDBMismatch;
// We validated the executable and pdb match.
const string_table_index = str_tab_index: {
const name_bytes_len = try pdb_stream.inStream().readIntLittle(u32);
const name_bytes = try allocator.alloc(u8, name_bytes_len);
try pdb_stream.inStream().readNoEof(name_bytes);
const HashTableHeader = packed struct {
Size: u32,
Capacity: u32,
fn maxLoad(cap: u32) u32 {
return cap * 2 / 3 + 1;
}
};
const hash_tbl_hdr = try pdb_stream.inStream().readStruct(HashTableHeader);
if (hash_tbl_hdr.Capacity == 0)
return error.InvalidDebugInfo;
if (hash_tbl_hdr.Size > HashTableHeader.maxLoad(hash_tbl_hdr.Capacity))
return error.InvalidDebugInfo;
const present = try readSparseBitVector(&pdb_stream.inStream(), allocator);
if (present.len != hash_tbl_hdr.Size)
return error.InvalidDebugInfo;
const deleted = try readSparseBitVector(&pdb_stream.inStream(), allocator);
const Bucket = struct {
first: u32,
second: u32,
};
const bucket_list = try allocator.alloc(Bucket, present.len);
for (present) |_| {
const name_offset = try pdb_stream.inStream().readIntLittle(u32);
const name_index = try pdb_stream.inStream().readIntLittle(u32);
const name = mem.toSlice(u8, @ptrCast([*:0]u8, name_bytes.ptr + name_offset));
if (mem.eql(u8, name, "/names")) {
break :str_tab_index name_index;
}
}
return error.MissingDebugInfo;
};
di.pdb.string_table = di.pdb.getStreamById(string_table_index) orelse return error.MissingDebugInfo;
di.pdb.dbi = di.pdb.getStream(pdb.StreamType.Dbi) orelse return error.MissingDebugInfo;
const dbi = di.pdb.dbi;
// Dbi Header
const dbi_stream_header = try dbi.inStream().readStruct(pdb.DbiStreamHeader);
if (dbi_stream_header.VersionHeader != 19990903) // V70, only value observed by LLVM team
return error.UnknownPDBVersion;
if (dbi_stream_header.Age != age)
return error.UnmatchingPDB;
const mod_info_size = dbi_stream_header.ModInfoSize;
const section_contrib_size = dbi_stream_header.SectionContributionSize;
var modules = ArrayList(Module).init(allocator);
// Module Info Substream
var mod_info_offset: usize = 0;
while (mod_info_offset != mod_info_size) {
const mod_info = try dbi.inStream().readStruct(pdb.ModInfo);
var this_record_len: usize = @sizeOf(pdb.ModInfo);
const module_name = try dbi.readNullTermString(allocator);
this_record_len += module_name.len + 1;
const obj_file_name = try dbi.readNullTermString(allocator);
this_record_len += obj_file_name.len + 1;
if (this_record_len % 4 != 0) {
const round_to_next_4 = (this_record_len | 0x3) + 1;
const march_forward_bytes = round_to_next_4 - this_record_len;
try dbi.seekBy(@intCast(isize, march_forward_bytes));
this_record_len += march_forward_bytes;
}
try modules.append(Module{
.mod_info = mod_info,
.module_name = module_name,
.obj_file_name = obj_file_name,
.populated = false,
.symbols = undefined,
.subsect_info = undefined,
.checksum_offset = null,
});
mod_info_offset += this_record_len;
if (mod_info_offset > mod_info_size)
return error.InvalidDebugInfo;
}
di.modules = modules.toOwnedSlice();
// Section Contribution Substream
var sect_contribs = ArrayList(pdb.SectionContribEntry).init(allocator);
var sect_cont_offset: usize = 0;
if (section_contrib_size != 0) {
const ver = @intToEnum(pdb.SectionContrSubstreamVersion, try dbi.inStream().readIntLittle(u32));
if (ver != pdb.SectionContrSubstreamVersion.Ver60)
return error.InvalidDebugInfo;
sect_cont_offset += @sizeOf(u32);
}
while (sect_cont_offset != section_contrib_size) {
const entry = try sect_contribs.addOne();
entry.* = try dbi.inStream().readStruct(pdb.SectionContribEntry);
sect_cont_offset += @sizeOf(pdb.SectionContribEntry);
if (sect_cont_offset > section_contrib_size)
return error.InvalidDebugInfo;
}
di.sect_contribs = sect_contribs.toOwnedSlice();
return di;
}
fn readSparseBitVector(stream: var, allocator: *mem.Allocator) ![]usize {
const num_words = try stream.readIntLittle(u32);
var word_i: usize = 0;
var list = ArrayList(usize).init(allocator);
while (word_i != num_words) : (word_i += 1) {
const word = try stream.readIntLittle(u32);
var bit_i: u5 = 0;
while (true) : (bit_i += 1) {
if (word & (@as(u32, 1) << bit_i) != 0) {
try list.append(word_i * 32 + bit_i);
}
if (bit_i == maxInt(u5)) break;
}
}
return list.toOwnedSlice();
}
fn chopSlice(ptr: []const u8, offset: u64, size: u64) ![]const u8 {
const start = try math.cast(usize, offset);
const end = start + try math.cast(usize, size);
return ptr[start..end];
}
/// TODO resources https://github.com/ziglang/zig/issues/4353
pub fn openElfDebugInfo(allocator: *mem.Allocator, elf_file_path: []const u8) !ModuleDebugInfo {
noasync {
const mapped_mem = try mapWholeFile(elf_file_path);
const hdr = @ptrCast(*const elf.Ehdr, &mapped_mem[0]);
if (!mem.eql(u8, hdr.e_ident[0..4], "\x7fELF")) return error.InvalidElfMagic;
if (hdr.e_ident[elf.EI_VERSION] != 1) return error.InvalidElfVersion;
const endian: builtin.Endian = switch (hdr.e_ident[elf.EI_DATA]) {
elf.ELFDATA2LSB => .Little,
elf.ELFDATA2MSB => .Big,
else => return error.InvalidElfEndian,
};
assert(endian == std.builtin.endian); // this is our own debug info
const shoff = hdr.e_shoff;
const str_section_off = shoff + @as(u64, hdr.e_shentsize) * @as(u64, hdr.e_shstrndx);
const str_shdr = @ptrCast(
*const elf.Shdr,
@alignCast(@alignOf(elf.Shdr), &mapped_mem[try math.cast(usize, str_section_off)]),
);
const header_strings = mapped_mem[str_shdr.sh_offset .. str_shdr.sh_offset + str_shdr.sh_size];
const shdrs = @ptrCast(
[*]const elf.Shdr,
@alignCast(@alignOf(elf.Shdr), &mapped_mem[shoff]),
)[0..hdr.e_shnum];
var opt_debug_info: ?[]const u8 = null;
var opt_debug_abbrev: ?[]const u8 = null;
var opt_debug_str: ?[]const u8 = null;
var opt_debug_line: ?[]const u8 = null;
var opt_debug_ranges: ?[]const u8 = null;
for (shdrs) |*shdr| {
if (shdr.sh_type == elf.SHT_NULL) continue;
const name = std.mem.span(@ptrCast([*:0]const u8, header_strings[shdr.sh_name..].ptr));
if (mem.eql(u8, name, ".debug_info")) {
opt_debug_info = try chopSlice(mapped_mem, shdr.sh_offset, shdr.sh_size);
} else if (mem.eql(u8, name, ".debug_abbrev")) {
opt_debug_abbrev = try chopSlice(mapped_mem, shdr.sh_offset, shdr.sh_size);
} else if (mem.eql(u8, name, ".debug_str")) {
opt_debug_str = try chopSlice(mapped_mem, shdr.sh_offset, shdr.sh_size);
} else if (mem.eql(u8, name, ".debug_line")) {
opt_debug_line = try chopSlice(mapped_mem, shdr.sh_offset, shdr.sh_size);
} else if (mem.eql(u8, name, ".debug_ranges")) {
opt_debug_ranges = try chopSlice(mapped_mem, shdr.sh_offset, shdr.sh_size);
}
}
var di = DW.DwarfInfo{
.endian = endian,
.debug_info = opt_debug_info orelse return error.MissingDebugInfo,
.debug_abbrev = opt_debug_abbrev orelse return error.MissingDebugInfo,
.debug_str = opt_debug_str orelse return error.MissingDebugInfo,
.debug_line = opt_debug_line orelse return error.MissingDebugInfo,
.debug_ranges = opt_debug_ranges,
};
try DW.openDwarfDebugInfo(&di, allocator);
return ModuleDebugInfo{
.base_address = undefined,
.dwarf = di,
.mapped_memory = mapped_mem,
};
}
}
/// TODO resources https://github.com/ziglang/zig/issues/4353
fn openMachODebugInfo(allocator: *mem.Allocator, macho_file_path: []const u8) !ModuleDebugInfo {
const mapped_mem = try mapWholeFile(macho_file_path);
const hdr = @ptrCast(
*const macho.mach_header_64,
@alignCast(@alignOf(macho.mach_header_64), mapped_mem.ptr),
);
if (hdr.magic != macho.MH_MAGIC_64)
return error.InvalidDebugInfo;
const hdr_base = @ptrCast([*]const u8, hdr);
var ptr = hdr_base + @sizeOf(macho.mach_header_64);
var ncmd: u32 = hdr.ncmds;
const symtab = while (ncmd != 0) : (ncmd -= 1) {
const lc = @ptrCast(*const std.macho.load_command, ptr);
switch (lc.cmd) {
std.macho.LC_SYMTAB => break @ptrCast(*const std.macho.symtab_command, ptr),
else => {},
}
ptr = @alignCast(@alignOf(std.macho.load_command), ptr + lc.cmdsize);
} else {
return error.MissingDebugInfo;
};
const syms = @ptrCast([*]const macho.nlist_64, @alignCast(@alignOf(macho.nlist_64), hdr_base + symtab.symoff))[0..symtab.nsyms];
const strings = @ptrCast([*]const u8, hdr_base + symtab.stroff)[0..symtab.strsize :0];
const symbols_buf = try allocator.alloc(MachoSymbol, syms.len);
var ofile: ?*const macho.nlist_64 = null;
var reloc: u64 = 0;
var symbol_index: usize = 0;
var last_len: u64 = 0;
for (syms) |*sym| {
if (sym.n_type & std.macho.N_STAB != 0) {
switch (sym.n_type) {
std.macho.N_OSO => {
ofile = sym;
reloc = 0;
},
std.macho.N_FUN => {
if (sym.n_sect == 0) {
last_len = sym.n_value;
} else {
symbols_buf[symbol_index] = MachoSymbol{
.nlist = sym,
.ofile = ofile,
.reloc = reloc,
};
symbol_index += 1;
}
},
std.macho.N_BNSYM => {
if (reloc == 0) {
reloc = sym.n_value;
}
},
else => continue,
}
}
}
const sentinel = try allocator.create(macho.nlist_64);
sentinel.* = macho.nlist_64{
.n_strx = 0,
.n_type = 36,
.n_sect = 0,
.n_desc = 0,
.n_value = symbols_buf[symbol_index - 1].nlist.n_value + last_len,
};
const symbols = allocator.shrink(symbols_buf, symbol_index);
// Even though lld emits symbols in ascending order, this debug code
// should work for programs linked in any valid way.
// This sort is so that we can binary search later.
std.sort.sort(MachoSymbol, symbols, MachoSymbol.addressLessThan);
return ModuleDebugInfo{
.base_address = undefined,
.mapped_memory = mapped_mem,
.ofiles = ModuleDebugInfo.OFileTable.init(allocator),
.symbols = symbols,
.strings = strings,
};
}
fn printLineFromFileAnyOs(out_stream: var, line_info: LineInfo) !void {
// 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(line_info.file_name, .{ .always_blocking = true });
defer f.close();
// TODO fstat and make sure that the file has the correct size
var buf: [mem.page_size]u8 = undefined;
var line: usize = 1;
var column: usize = 1;
var abs_index: usize = 0;
while (true) {
const amt_read = try f.read(buf[0..]);
const slice = buf[0..amt_read];
for (slice) |byte| {
if (line == line_info.line) {
try out_stream.writeByte(byte);
if (byte == '\n') {
return;
}
}
if (byte == '\n') {
line += 1;
column = 1;
} else {
column += 1;
}
}
if (amt_read < buf.len) return error.EndOfFile;
}
}
const MachoSymbol = struct {
nlist: *const macho.nlist_64,
ofile: ?*const macho.nlist_64,
reloc: u64,
/// Returns the address from the macho file
fn address(self: MachoSymbol) u64 {
return self.nlist.n_value;
}
fn addressLessThan(lhs: MachoSymbol, rhs: MachoSymbol) bool {
return lhs.address() < rhs.address();
}
};
fn mapWholeFile(path: []const u8) ![]align(mem.page_size) const u8 {
noasync {
const file = try fs.openFileAbsolute(path, .{ .always_blocking = true });
defer file.close();
const file_len = try math.cast(usize, try file.getEndPos());
const mapped_mem = try os.mmap(
null,
file_len,
os.PROT_READ,
os.MAP_SHARED,
file.handle,
0,
);
errdefer os.munmap(mapped_mem);
return mapped_mem;
}
}
pub const DebugInfo = struct {
allocator: *mem.Allocator,
address_map: std.AutoHashMap(usize, *ModuleDebugInfo),
pub fn init(allocator: *mem.Allocator) DebugInfo {
return DebugInfo{
.allocator = allocator,
.address_map = std.AutoHashMap(usize, *ModuleDebugInfo).init(allocator),
};
}
pub fn deinit(self: *DebugInfo) void {
// TODO: resources https://github.com/ziglang/zig/issues/4353
self.address_map.deinit();
}
pub fn getModuleForAddress(self: *DebugInfo, address: usize) !*ModuleDebugInfo {
if (comptime std.Target.current.isDarwin())
return self.lookupModuleDyld(address)
else if (builtin.os.tag == .windows)
return self.lookupModuleWin32(address)
else
return self.lookupModuleDl(address);
}
fn lookupModuleDyld(self: *DebugInfo, address: usize) !*ModuleDebugInfo {
const image_count = std.c._dyld_image_count();
var i: u32 = 0;
while (i < image_count) : (i += 1) {
const base_address = std.c._dyld_get_image_vmaddr_slide(i);
if (address < base_address) continue;
const header = std.c._dyld_get_image_header(i) orelse continue;
// The array of load commands is right after the header
var cmd_ptr = @intToPtr([*]u8, @ptrToInt(header) + @sizeOf(macho.mach_header_64));
var cmds = header.ncmds;
while (cmds != 0) : (cmds -= 1) {
const lc = @ptrCast(
*macho.load_command,
@alignCast(@alignOf(macho.load_command), cmd_ptr),
);
cmd_ptr += lc.cmdsize;
if (lc.cmd != macho.LC_SEGMENT_64) continue;
const segment_cmd = @ptrCast(
*const std.macho.segment_command_64,
@alignCast(@alignOf(std.macho.segment_command_64), lc),
);
const rebased_address = address - base_address;
const seg_start = segment_cmd.vmaddr;
const seg_end = seg_start + segment_cmd.vmsize;
if (rebased_address >= seg_start and rebased_address < seg_end) {
if (self.address_map.getValue(base_address)) |obj_di| {
return obj_di;
}
const obj_di = try self.allocator.create(ModuleDebugInfo);
errdefer self.allocator.destroy(obj_di);
const macho_path = mem.toSliceConst(u8, std.c._dyld_get_image_name(i));
obj_di.* = openMachODebugInfo(self.allocator, macho_path) catch |err| switch (err) {
error.FileNotFound => return error.MissingDebugInfo,
else => return err,
};
obj_di.base_address = base_address;
try self.address_map.putNoClobber(base_address, obj_di);
return obj_di;
}
}
}
return error.MissingDebugInfo;
}
fn lookupModuleWin32(self: *DebugInfo, address: usize) !*ModuleDebugInfo {
const process_handle = windows.kernel32.GetCurrentProcess();
// Find how many modules are actually loaded
var dummy: windows.HMODULE = undefined;
var bytes_needed: windows.DWORD = undefined;
if (windows.kernel32.K32EnumProcessModules(
process_handle,
@ptrCast([*]windows.HMODULE, &dummy),
0,
&bytes_needed,
) == 0)
return error.MissingDebugInfo;
const needed_modules = bytes_needed / @sizeOf(windows.HMODULE);
// Fetch the complete module list
var modules = try self.allocator.alloc(windows.HMODULE, needed_modules);
defer self.allocator.free(modules);
if (windows.kernel32.K32EnumProcessModules(
process_handle,
modules.ptr,
try math.cast(windows.DWORD, modules.len * @sizeOf(windows.HMODULE)),
&bytes_needed,
) == 0)
return error.MissingDebugInfo;
// There's an unavoidable TOCTOU problem here, the module list may have
// changed between the two EnumProcessModules call.
// Pick the smallest amount of elements to avoid processing garbage.
const needed_modules_after = bytes_needed / @sizeOf(windows.HMODULE);
const loaded_modules = math.min(needed_modules, needed_modules_after);
for (modules[0..loaded_modules]) |module| {
var info: windows.MODULEINFO = undefined;
if (windows.kernel32.K32GetModuleInformation(
process_handle,
module,
&info,
@sizeOf(@TypeOf(info)),
) == 0)
return error.MissingDebugInfo;
const seg_start = @ptrToInt(info.lpBaseOfDll);
const seg_end = seg_start + info.SizeOfImage;
if (address >= seg_start and address < seg_end) {
if (self.address_map.getValue(seg_start)) |obj_di| {
return obj_di;
}
var name_buffer: [windows.PATH_MAX_WIDE + 4:0]u16 = undefined;
// openFileAbsoluteW requires the prefix to be present
mem.copy(u16, name_buffer[0..4], &[_]u16{ '\\', '?', '?', '\\' });
const len = windows.kernel32.K32GetModuleFileNameExW(
process_handle,
module,
@ptrCast(windows.LPWSTR, &name_buffer[4]),
windows.PATH_MAX_WIDE,
);
assert(len > 0);
const obj_di = try self.allocator.create(ModuleDebugInfo);
errdefer self.allocator.destroy(obj_di);
obj_di.* = openCoffDebugInfo(self.allocator, name_buffer[0..:0]) catch |err| switch (err) {
error.FileNotFound => return error.MissingDebugInfo,
else => return err,
};
obj_di.base_address = seg_start;
try self.address_map.putNoClobber(seg_start, obj_di);
return obj_di;
}
}
return error.MissingDebugInfo;
}
fn lookupModuleDl(self: *DebugInfo, address: usize) !*ModuleDebugInfo {
var ctx: struct {
// Input
address: usize,
// Output
base_address: usize = undefined,
name: []const u8 = undefined,
} = .{ .address = address };
const CtxTy = @TypeOf(ctx);
if (os.dl_iterate_phdr(&ctx, anyerror, struct {
fn callback(info: *os.dl_phdr_info, size: usize, context: *CtxTy) !void {
// The base address is too high
if (context.address < info.dlpi_addr)
return;
const phdrs = info.dlpi_phdr[0..info.dlpi_phnum];
for (phdrs) |*phdr| {
if (phdr.p_type != elf.PT_LOAD) continue;
const seg_start = info.dlpi_addr + phdr.p_vaddr;
const seg_end = seg_start + phdr.p_memsz;
if (context.address >= seg_start and context.address < seg_end) {
// Android libc uses NULL instead of an empty string to mark the
// main program
context.name = if (info.dlpi_name) |dlpi_name|
mem.toSliceConst(u8, dlpi_name)
else
"";
context.base_address = info.dlpi_addr;
// Stop the iteration
return error.Found;
}
}
}
}.callback)) {
return error.MissingDebugInfo;
} else |err| switch (err) {
error.Found => {},
else => return error.MissingDebugInfo,
}
if (self.address_map.getValue(ctx.base_address)) |obj_di| {
return obj_di;
}
const elf_path = if (ctx.name.len > 0)
ctx.name
else blk: {
var buf: [fs.MAX_PATH_BYTES]u8 = undefined;
break :blk try fs.selfExePath(&buf);
};
const obj_di = try self.allocator.create(ModuleDebugInfo);
errdefer self.allocator.destroy(obj_di);
obj_di.* = openElfDebugInfo(self.allocator, elf_path) catch |err| switch (err) {
error.FileNotFound => return error.MissingDebugInfo,
else => return err,
};
obj_di.base_address = ctx.base_address;
try self.address_map.putNoClobber(ctx.base_address, obj_di);
return obj_di;
}
};
const SymbolInfo = struct {
symbol_name: []const u8 = "???",
compile_unit_name: []const u8 = "???",
line_info: ?LineInfo = null,
fn deinit(self: @This()) void {
if (self.line_info) |li| {
li.deinit();
}
}
};
pub const ModuleDebugInfo = switch (builtin.os.tag) {
.macosx, .ios, .watchos, .tvos => struct {
base_address: usize,
mapped_memory: []const u8,
symbols: []const MachoSymbol,
strings: [:0]const u8,
ofiles: OFileTable,
const OFileTable = std.StringHashMap(DW.DwarfInfo);
pub fn allocator(self: @This()) *mem.Allocator {
return self.ofiles.allocator;
}
fn loadOFile(self: *@This(), o_file_path: []const u8) !DW.DwarfInfo {
const mapped_mem = try mapWholeFile(o_file_path);
const hdr = @ptrCast(
*const macho.mach_header_64,
@alignCast(@alignOf(macho.mach_header_64), mapped_mem.ptr),
);
if (hdr.magic != std.macho.MH_MAGIC_64)
return error.InvalidDebugInfo;
const hdr_base = @ptrCast([*]const u8, hdr);
var ptr = hdr_base + @sizeOf(macho.mach_header_64);
var ncmd: u32 = hdr.ncmds;
const segcmd = while (ncmd != 0) : (ncmd -= 1) {
const lc = @ptrCast(*const std.macho.load_command, ptr);
switch (lc.cmd) {
std.macho.LC_SEGMENT_64 => {
break @ptrCast(
*const std.macho.segment_command_64,
@alignCast(@alignOf(std.macho.segment_command_64), ptr),
);
},
else => {},
}
ptr = @alignCast(@alignOf(std.macho.load_command), ptr + lc.cmdsize);
} else {
return error.MissingDebugInfo;
};
var opt_debug_line: ?*const macho.section_64 = null;
var opt_debug_info: ?*const macho.section_64 = null;
var opt_debug_abbrev: ?*const macho.section_64 = null;
var opt_debug_str: ?*const macho.section_64 = null;
var opt_debug_ranges: ?*const macho.section_64 = null;
const sections = @ptrCast(
[*]const macho.section_64,
@alignCast(@alignOf(macho.section_64), ptr + @sizeOf(std.macho.segment_command_64)),
)[0..segcmd.nsects];
for (sections) |*sect| {
// The section name may not exceed 16 chars and a trailing null may
// not be present
const name = if (mem.indexOfScalar(u8, sect.sectname[0..], 0)) |last|
sect.sectname[0..last]
else
sect.sectname[0..];
if (mem.eql(u8, name, "__debug_line")) {
opt_debug_line = sect;
} else if (mem.eql(u8, name, "__debug_info")) {
opt_debug_info = sect;
} else if (mem.eql(u8, name, "__debug_abbrev")) {
opt_debug_abbrev = sect;
} else if (mem.eql(u8, name, "__debug_str")) {
opt_debug_str = sect;
} else if (mem.eql(u8, name, "__debug_ranges")) {
opt_debug_ranges = sect;
}
}
const debug_line = opt_debug_line orelse
return error.MissingDebugInfo;
const debug_info = opt_debug_info orelse
return error.MissingDebugInfo;
const debug_str = opt_debug_str orelse
return error.MissingDebugInfo;
const debug_abbrev = opt_debug_abbrev orelse
return error.MissingDebugInfo;
var di = DW.DwarfInfo{
.endian = .Little,
.debug_info = try chopSlice(mapped_mem, debug_info.offset, debug_info.size),
.debug_abbrev = try chopSlice(mapped_mem, debug_abbrev.offset, debug_abbrev.size),
.debug_str = try chopSlice(mapped_mem, debug_str.offset, debug_str.size),
.debug_line = try chopSlice(mapped_mem, debug_line.offset, debug_line.size),
.debug_ranges = if (opt_debug_ranges) |debug_ranges|
try chopSlice(mapped_mem, debug_ranges.offset, debug_ranges.size)
else
null,
};
try DW.openDwarfDebugInfo(&di, self.allocator());
// Add the debug info to the cache
try self.ofiles.putNoClobber(o_file_path, di);
return di;
}
fn getSymbolAtAddress(self: *@This(), address: usize) !SymbolInfo {
// Translate the VA into an address into this object
const relocated_address = address - self.base_address;
assert(relocated_address >= 0x100000000);
// Find the .o file where this symbol is defined
const symbol = machoSearchSymbols(self.symbols, relocated_address) orelse
return SymbolInfo{};
// XXX: Return the symbol name
if (symbol.ofile == null)
return SymbolInfo{};
assert(symbol.ofile.?.n_strx < self.strings.len);
const o_file_path = mem.toSliceConst(u8, self.strings.ptr + symbol.ofile.?.n_strx);
// Check if its debug infos are already in the cache
var o_file_di = self.ofiles.getValue(o_file_path) orelse
(self.loadOFile(o_file_path) catch |err| switch (err) {
error.MissingDebugInfo, error.InvalidDebugInfo => {
// XXX: Return the symbol name
return SymbolInfo{};
},
else => return err,
});
// Translate again the address, this time into an address inside the
// .o file
const relocated_address_o = relocated_address - symbol.reloc;
if (o_file_di.findCompileUnit(relocated_address_o)) |compile_unit| {
return SymbolInfo{
.symbol_name = o_file_di.getSymbolName(relocated_address_o) orelse "???",
.compile_unit_name = compile_unit.die.getAttrString(&o_file_di, DW.AT_name) catch |err| switch (err) {
error.MissingDebugInfo, error.InvalidDebugInfo => "???",
else => return err,
},
.line_info = o_file_di.getLineNumberInfo(compile_unit.*, relocated_address_o) catch |err| switch (err) {
error.MissingDebugInfo, error.InvalidDebugInfo => null,
else => return err,
},
};
} else |err| switch (err) {
error.MissingDebugInfo, error.InvalidDebugInfo => {
return SymbolInfo{};
},
else => return err,
}
unreachable;
}
},
.uefi, .windows => struct {
base_address: usize,
pdb: pdb.Pdb,
coff: *coff.Coff,
sect_contribs: []pdb.SectionContribEntry,
modules: []Module,
pub fn allocator(self: @This()) *mem.Allocator {
return self.coff.allocator;
}
fn getSymbolAtAddress(self: *@This(), address: usize) !SymbolInfo {
// Translate the VA into an address into this object
const relocated_address = address - self.base_address;
var coff_section: *coff.Section = undefined;
const mod_index = for (self.sect_contribs) |sect_contrib| {
if (sect_contrib.Section > self.coff.sections.len) continue;
// Remember that SectionContribEntry.Section is 1-based.
coff_section = &self.coff.sections.toSlice()[sect_contrib.Section - 1];
const vaddr_start = coff_section.header.virtual_address + sect_contrib.Offset;
const vaddr_end = vaddr_start + sect_contrib.Size;
if (relocated_address >= vaddr_start and relocated_address < vaddr_end) {
break sect_contrib.ModuleIndex;
}
} else {
// we have no information to add to the address
return SymbolInfo{};
};
const mod = &self.modules[mod_index];
try populateModule(self, mod);
const obj_basename = fs.path.basename(mod.obj_file_name);
var symbol_i: usize = 0;
const symbol_name = if (!mod.populated) "???" else while (symbol_i != mod.symbols.len) {
const prefix = @ptrCast(*pdb.RecordPrefix, &mod.symbols[symbol_i]);
if (prefix.RecordLen < 2)
return error.InvalidDebugInfo;
switch (prefix.RecordKind) {
.S_LPROC32, .S_GPROC32 => {
const proc_sym = @ptrCast(*pdb.ProcSym, &mod.symbols[symbol_i + @sizeOf(pdb.RecordPrefix)]);
const vaddr_start = coff_section.header.virtual_address + proc_sym.CodeOffset;
const vaddr_end = vaddr_start + proc_sym.CodeSize;
if (relocated_address >= vaddr_start and relocated_address < vaddr_end) {
break mem.toSliceConst(u8, @ptrCast([*:0]u8, proc_sym) + @sizeOf(pdb.ProcSym));
}
},
else => {},
}
symbol_i += prefix.RecordLen + @sizeOf(u16);
if (symbol_i > mod.symbols.len)
return error.InvalidDebugInfo;
} else "???";
const subsect_info = mod.subsect_info;
var sect_offset: usize = 0;
var skip_len: usize = undefined;
const opt_line_info = subsections: {
const checksum_offset = mod.checksum_offset orelse break :subsections null;
while (sect_offset != subsect_info.len) : (sect_offset += skip_len) {
const subsect_hdr = @ptrCast(*pdb.DebugSubsectionHeader, &subsect_info[sect_offset]);
skip_len = subsect_hdr.Length;
sect_offset += @sizeOf(pdb.DebugSubsectionHeader);
switch (subsect_hdr.Kind) {
.Lines => {
var line_index = sect_offset;
const line_hdr = @ptrCast(*pdb.LineFragmentHeader, &subsect_info[line_index]);
if (line_hdr.RelocSegment == 0)
return error.MissingDebugInfo;
line_index += @sizeOf(pdb.LineFragmentHeader);
const frag_vaddr_start = coff_section.header.virtual_address + line_hdr.RelocOffset;
const frag_vaddr_end = frag_vaddr_start + line_hdr.CodeSize;
if (relocated_address >= frag_vaddr_start and relocated_address < frag_vaddr_end) {
// There is an unknown number of LineBlockFragmentHeaders (and their accompanying line and column records)
// from now on. We will iterate through them, and eventually find a LineInfo that we're interested in,
// breaking out to :subsections. If not, we will make sure to not read anything outside of this subsection.
const subsection_end_index = sect_offset + subsect_hdr.Length;
while (line_index < subsection_end_index) {
const block_hdr = @ptrCast(*pdb.LineBlockFragmentHeader, &subsect_info[line_index]);
line_index += @sizeOf(pdb.LineBlockFragmentHeader);
const start_line_index = line_index;
const has_column = line_hdr.Flags.LF_HaveColumns;
// All line entries are stored inside their line block by ascending start address.
// Heuristic: we want to find the last line entry
// that has a vaddr_start <= relocated_address.
// This is done with a simple linear search.
var line_i: u32 = 0;
while (line_i < block_hdr.NumLines) : (line_i += 1) {
const line_num_entry = @ptrCast(*pdb.LineNumberEntry, &subsect_info[line_index]);
line_index += @sizeOf(pdb.LineNumberEntry);
const vaddr_start = frag_vaddr_start + line_num_entry.Offset;
if (relocated_address < vaddr_start) {
break;
}
}
// line_i == 0 would mean that no matching LineNumberEntry was found.
if (line_i > 0) {
const subsect_index = checksum_offset + block_hdr.NameIndex;
const chksum_hdr = @ptrCast(*pdb.FileChecksumEntryHeader, &mod.subsect_info[subsect_index]);
const strtab_offset = @sizeOf(pdb.PDBStringTableHeader) + chksum_hdr.FileNameOffset;
try self.pdb.string_table.seekTo(strtab_offset);
const source_file_name = try self.pdb.string_table.readNullTermString(self.allocator());
const line_entry_idx = line_i - 1;
const column = if (has_column) blk: {
const start_col_index = start_line_index + @sizeOf(pdb.LineNumberEntry) * block_hdr.NumLines;
const col_index = start_col_index + @sizeOf(pdb.ColumnNumberEntry) * line_entry_idx;
const col_num_entry = @ptrCast(*pdb.ColumnNumberEntry, &subsect_info[col_index]);
break :blk col_num_entry.StartColumn;
} else 0;
const found_line_index = start_line_index + line_entry_idx * @sizeOf(pdb.LineNumberEntry);
const line_num_entry = @ptrCast(*pdb.LineNumberEntry, &subsect_info[found_line_index]);
const flags = @ptrCast(*pdb.LineNumberEntry.Flags, &line_num_entry.Flags);
break :subsections LineInfo{
.allocator = self.allocator(),
.file_name = source_file_name,
.line = flags.Start,
.column = column,
};
}
}
// Checking that we are not reading garbage after the (possibly) multiple block fragments.
if (line_index != subsection_end_index) {
return error.InvalidDebugInfo;
}
}
},
else => {},
}
if (sect_offset > subsect_info.len)
return error.InvalidDebugInfo;
} else {
break :subsections null;
}
};
return SymbolInfo{
.symbol_name = symbol_name,
.compile_unit_name = obj_basename,
.line_info = opt_line_info,
};
}
},
.linux, .freebsd => struct {
base_address: usize,
dwarf: DW.DwarfInfo,
mapped_memory: []const u8,
fn getSymbolAtAddress(self: *@This(), address: usize) !SymbolInfo {
// Translate the VA into an address into this object
const relocated_address = address - self.base_address;
if (noasync self.dwarf.findCompileUnit(relocated_address)) |compile_unit| {
return SymbolInfo{
.symbol_name = noasync self.dwarf.getSymbolName(relocated_address) orelse "???",
.compile_unit_name = compile_unit.die.getAttrString(&self.dwarf, DW.AT_name) catch |err| switch (err) {
error.MissingDebugInfo, error.InvalidDebugInfo => "???",
else => return err,
},
.line_info = noasync self.dwarf.getLineNumberInfo(compile_unit.*, relocated_address) catch |err| switch (err) {
error.MissingDebugInfo, error.InvalidDebugInfo => null,
else => return err,
},
};
} else |err| switch (err) {
error.MissingDebugInfo, error.InvalidDebugInfo => {
return SymbolInfo{};
},
else => return err,
}
unreachable;
}
},
else => DW.DwarfInfo,
};
/// TODO multithreaded awareness
var debug_info_allocator: ?*mem.Allocator = null;
var debug_info_arena_allocator: std.heap.ArenaAllocator = undefined;
fn getDebugInfoAllocator() *mem.Allocator {
if (debug_info_allocator) |a| return a;
debug_info_arena_allocator = std.heap.ArenaAllocator.init(std.heap.page_allocator);
debug_info_allocator = &debug_info_arena_allocator.allocator;
return &debug_info_arena_allocator.allocator;
}
/// Whether or not the current target can print useful debug information when a segfault occurs.
pub const have_segfault_handling_support = builtin.os.tag == .linux or builtin.os.tag == .windows;
pub const enable_segfault_handler: bool = if (@hasDecl(root, "enable_segfault_handler"))
root.enable_segfault_handler
else
runtime_safety and have_segfault_handling_support;
pub fn maybeEnableSegfaultHandler() void {
if (enable_segfault_handler) {
std.debug.attachSegfaultHandler();
}
}
var windows_segfault_handle: ?windows.HANDLE = null;
/// Attaches a global SIGSEGV handler which calls @panic("segmentation fault");
pub fn attachSegfaultHandler() void {
if (!have_segfault_handling_support) {
@compileError("segfault handler not supported for this target");
}
if (builtin.os.tag == .windows) {
windows_segfault_handle = windows.kernel32.AddVectoredExceptionHandler(0, handleSegfaultWindows);
return;
}
var act = os.Sigaction{
.sigaction = handleSegfaultLinux,
.mask = os.empty_sigset,
.flags = (os.SA_SIGINFO | os.SA_RESTART | os.SA_RESETHAND),
};
os.sigaction(os.SIGSEGV, &act, null);
os.sigaction(os.SIGILL, &act, null);
os.sigaction(os.SIGBUS, &act, null);
}
fn resetSegfaultHandler() void {
if (builtin.os.tag == .windows) {
if (windows_segfault_handle) |handle| {
assert(windows.kernel32.RemoveVectoredExceptionHandler(handle) != 0);
windows_segfault_handle = null;
}
return;
}
var act = os.Sigaction{
.sigaction = os.SIG_DFL,
.mask = os.empty_sigset,
.flags = 0,
};
os.sigaction(os.SIGSEGV, &act, null);
os.sigaction(os.SIGILL, &act, null);
os.sigaction(os.SIGBUS, &act, null);
}
fn handleSegfaultLinux(sig: i32, info: *const os.siginfo_t, ctx_ptr: *const c_void) callconv(.C) noreturn {
// Reset to the default handler so that if a segfault happens in this handler it will crash
// the process. Also when this handler returns, the original instruction will be repeated
// and the resulting segfault will crash the process rather than continually dump stack traces.
resetSegfaultHandler();
const addr = @ptrToInt(info.fields.sigfault.addr);
switch (sig) {
os.SIGSEGV => std.debug.warn("Segmentation fault at address 0x{x}\n", .{addr}),
os.SIGILL => std.debug.warn("Illegal instruction at address 0x{x}\n", .{addr}),
os.SIGBUS => std.debug.warn("Bus error at address 0x{x}\n", .{addr}),
else => unreachable,
}
switch (builtin.arch) {
.i386 => {
const ctx = @ptrCast(*const os.ucontext_t, @alignCast(@alignOf(os.ucontext_t), ctx_ptr));
const ip = @intCast(usize, ctx.mcontext.gregs[os.REG_EIP]);
const bp = @intCast(usize, ctx.mcontext.gregs[os.REG_EBP]);
dumpStackTraceFromBase(bp, ip);
},
.x86_64 => {
const ctx = @ptrCast(*const os.ucontext_t, @alignCast(@alignOf(os.ucontext_t), ctx_ptr));
const ip = @intCast(usize, ctx.mcontext.gregs[os.REG_RIP]);
const bp = @intCast(usize, ctx.mcontext.gregs[os.REG_RBP]);
dumpStackTraceFromBase(bp, ip);
},
.arm => {
const ctx = @ptrCast(*const os.ucontext_t, @alignCast(@alignOf(os.ucontext_t), ctx_ptr));
const ip = @intCast(usize, ctx.mcontext.arm_pc);
const bp = @intCast(usize, ctx.mcontext.arm_fp);
dumpStackTraceFromBase(bp, ip);
},
.aarch64 => {
const ctx = @ptrCast(*const os.ucontext_t, @alignCast(@alignOf(os.ucontext_t), ctx_ptr));
const ip = @intCast(usize, ctx.mcontext.pc);
// x29 is the ABI-designated frame pointer
const bp = @intCast(usize, ctx.mcontext.regs[29]);
dumpStackTraceFromBase(bp, ip);
},
else => {},
}
// 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.
os.abort();
}
fn handleSegfaultWindows(info: *windows.EXCEPTION_POINTERS) callconv(.Stdcall) c_long {
switch (info.ExceptionRecord.ExceptionCode) {
windows.EXCEPTION_DATATYPE_MISALIGNMENT => handleSegfaultWindowsExtra(info, 0, "Unaligned Memory Access"),
windows.EXCEPTION_ACCESS_VIOLATION => handleSegfaultWindowsExtra(info, 1, null),
windows.EXCEPTION_ILLEGAL_INSTRUCTION => handleSegfaultWindowsExtra(info, 2, null),
windows.EXCEPTION_STACK_OVERFLOW => handleSegfaultWindowsExtra(info, 0, "Stack Overflow"),
else => return windows.EXCEPTION_CONTINUE_SEARCH,
}
}
// zig won't let me use an anon enum here https://github.com/ziglang/zig/issues/3707
fn handleSegfaultWindowsExtra(info: *windows.EXCEPTION_POINTERS, comptime msg: u8, comptime format: ?[]const u8) noreturn {
const exception_address = @ptrToInt(info.ExceptionRecord.ExceptionAddress);
if (@hasDecl(windows, "CONTEXT")) {
const regs = info.ContextRecord.getRegs();
switch (msg) {
0 => std.debug.warn("{}\n", .{format.?}),
1 => std.debug.warn("Segmentation fault at address 0x{x}\n", .{info.ExceptionRecord.ExceptionInformation[1]}),
2 => std.debug.warn("Illegal instruction at address 0x{x}\n", .{regs.ip}),
else => unreachable,
}
dumpStackTraceFromBase(regs.bp, regs.ip);
os.abort();
} else {
switch (msg) {
0 => panicExtra(null, exception_address, format.?, .{}),
1 => panicExtra(null, exception_address, "Segmentation fault at address 0x{x}", .{info.ExceptionRecord.ExceptionInformation[1]}),
2 => panicExtra(null, exception_address, "Illegal Instruction", .{}),
else => unreachable,
}
}
}
pub fn dumpStackPointerAddr(prefix: []const u8) void {
const sp = asm (""
: [argc] "={rsp}" (-> usize)
);
std.debug.warn("{} sp = 0x{x}\n", .{ prefix, sp });
}
// Reference everything so it gets tested.
test "" {
_ = leb;
}
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