mirror of
https://github.com/ziglang/zig.git
synced 2026-02-20 00:08:56 +00:00
macos: rewrite logic for generating stack traces on macOS
In order to be linker-independent, when parsing debug info in each linked OSO, we also create a quick lookup table for symbols defined within the OSO. We then use this lookup to map symbol from the EXE to its defined address within the original OSO which we can then use to extract its associated DWARF info (if any).
This commit is contained in:
Jakub Konka
parent
86fe47235e
commit
a56749b654
@ -559,7 +559,7 @@ pub const TTY = struct {
|
||||
|
||||
fn machoSearchSymbols(symbols: []const MachoSymbol, address: usize) ?*const MachoSymbol {
|
||||
var min: usize = 0;
|
||||
var max: usize = symbols.len - 1; // Exclude sentinel.
|
||||
var max: usize = symbols.len;
|
||||
while (min < max) {
|
||||
const mid = min + (max - min) / 2;
|
||||
const curr = &symbols[mid];
|
||||
@ -850,51 +850,91 @@ fn readMachODebugInfo(allocator: *mem.Allocator, macho_file: File) !ModuleDebugI
|
||||
} else {
|
||||
return error.MissingDebugInfo;
|
||||
};
|
||||
const syms = @ptrCast([*]const macho.nlist_64, @alignCast(@alignOf(macho.nlist_64), hdr_base + symtab.symoff))[0..symtab.nsyms];
|
||||
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 - 1 :0];
|
||||
|
||||
const symbols_buf = try allocator.alloc(MachoSymbol, syms.len);
|
||||
|
||||
var ofile: ?*const macho.nlist_64 = null;
|
||||
var reloc: u64 = 0;
|
||||
var ofile: u32 = undefined;
|
||||
var last_sym: MachoSymbol = undefined;
|
||||
var symbol_index: usize = 0;
|
||||
var last_len: u64 = 0;
|
||||
var state: enum {
|
||||
init,
|
||||
oso_open,
|
||||
oso_close,
|
||||
bnsym,
|
||||
fun_strx,
|
||||
fun_size,
|
||||
ensym,
|
||||
} = .init;
|
||||
|
||||
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,
|
||||
if (!sym.stab()) continue;
|
||||
|
||||
// TODO handle globals N_GSYM, and statics N_STSYM
|
||||
switch (sym.n_type) {
|
||||
macho.N_OSO => {
|
||||
switch (state) {
|
||||
.init, .oso_close => {
|
||||
state = .oso_open;
|
||||
ofile = sym.n_strx;
|
||||
},
|
||||
else => return error.InvalidDebugInfo,
|
||||
}
|
||||
},
|
||||
macho.N_BNSYM => {
|
||||
switch (state) {
|
||||
.oso_open, .ensym => {
|
||||
state = .bnsym;
|
||||
last_sym = .{
|
||||
.strx = 0,
|
||||
.addr = sym.n_value,
|
||||
.size = 0,
|
||||
.ofile = ofile,
|
||||
.reloc = reloc,
|
||||
};
|
||||
},
|
||||
else => return error.InvalidDebugInfo,
|
||||
}
|
||||
},
|
||||
macho.N_FUN => {
|
||||
switch (state) {
|
||||
.bnsym => {
|
||||
state = .fun_strx;
|
||||
last_sym.strx = sym.n_strx;
|
||||
},
|
||||
.fun_strx => {
|
||||
state = .fun_size;
|
||||
last_sym.size = @intCast(u32, sym.n_value);
|
||||
},
|
||||
else => return error.InvalidDebugInfo,
|
||||
}
|
||||
},
|
||||
macho.N_ENSYM => {
|
||||
switch (state) {
|
||||
.fun_size => {
|
||||
state = .ensym;
|
||||
symbols_buf[symbol_index] = last_sym;
|
||||
symbol_index += 1;
|
||||
}
|
||||
},
|
||||
std.macho.N_BNSYM => {
|
||||
if (reloc == 0) {
|
||||
reloc = sym.n_value;
|
||||
}
|
||||
},
|
||||
else => continue,
|
||||
}
|
||||
},
|
||||
else => return error.InvalidDebugInfo,
|
||||
}
|
||||
},
|
||||
macho.N_SO => {
|
||||
switch (state) {
|
||||
.init, .oso_close => {},
|
||||
.oso_open, .ensym => {
|
||||
state = .oso_close;
|
||||
},
|
||||
else => return error.InvalidDebugInfo,
|
||||
}
|
||||
},
|
||||
else => {},
|
||||
}
|
||||
}
|
||||
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,
|
||||
};
|
||||
assert(state == .oso_close);
|
||||
|
||||
const symbols = allocator.shrink(symbols_buf, symbol_index);
|
||||
|
||||
@ -946,18 +986,19 @@ fn printLineFromFileAnyOs(out_stream: anytype, line_info: LineInfo) !void {
|
||||
}
|
||||
|
||||
const MachoSymbol = struct {
|
||||
nlist: *const macho.nlist_64,
|
||||
ofile: ?*const macho.nlist_64,
|
||||
reloc: u64,
|
||||
strx: u32,
|
||||
addr: u64,
|
||||
size: u32,
|
||||
ofile: u32,
|
||||
|
||||
/// Returns the address from the macho file
|
||||
fn address(self: MachoSymbol) u64 {
|
||||
return self.nlist.n_value;
|
||||
return self.addr;
|
||||
}
|
||||
|
||||
fn addressLessThan(context: void, lhs: MachoSymbol, rhs: MachoSymbol) bool {
|
||||
_ = context;
|
||||
return lhs.address() < rhs.address();
|
||||
return lhs.addr < rhs.addr;
|
||||
}
|
||||
};
|
||||
|
||||
@ -1231,13 +1272,17 @@ pub const ModuleDebugInfo = switch (native_os) {
|
||||
strings: [:0]const u8,
|
||||
ofiles: OFileTable,
|
||||
|
||||
const OFileTable = std.StringHashMap(DW.DwarfInfo);
|
||||
const OFileTable = std.StringHashMap(OFileInfo);
|
||||
const OFileInfo = struct {
|
||||
di: DW.DwarfInfo,
|
||||
addr_table: std.StringHashMap(u64),
|
||||
};
|
||||
|
||||
pub fn allocator(self: @This()) *mem.Allocator {
|
||||
return self.ofiles.allocator;
|
||||
}
|
||||
|
||||
fn loadOFile(self: *@This(), o_file_path: []const u8) !DW.DwarfInfo {
|
||||
fn loadOFile(self: *@This(), o_file_path: []const u8) !OFileInfo {
|
||||
const o_file = try fs.cwd().openFile(o_file_path, .{ .intended_io_mode = .blocking });
|
||||
const mapped_mem = try mapWholeFile(o_file);
|
||||
|
||||
@ -1250,22 +1295,54 @@ pub const ModuleDebugInfo = switch (native_os) {
|
||||
|
||||
const hdr_base = @ptrCast([*]const u8, hdr);
|
||||
var ptr = hdr_base + @sizeOf(macho.mach_header_64);
|
||||
var segptr = ptr;
|
||||
var ncmd: u32 = hdr.ncmds;
|
||||
const segcmd = while (ncmd != 0) : (ncmd -= 1) {
|
||||
var segcmd: ?*const macho.segment_command_64 = null;
|
||||
var symtabcmd: ?*const macho.symtab_command = null;
|
||||
|
||||
while (ncmd != 0) : (ncmd -= 1) {
|
||||
const lc = @ptrCast(*const std.macho.load_command, ptr);
|
||||
switch (lc.cmd) {
|
||||
std.macho.LC_SEGMENT_64 => {
|
||||
break @ptrCast(
|
||||
segcmd = @ptrCast(
|
||||
*const std.macho.segment_command_64,
|
||||
@alignCast(@alignOf(std.macho.segment_command_64), ptr),
|
||||
);
|
||||
segptr = ptr;
|
||||
},
|
||||
std.macho.LC_SYMTAB => {
|
||||
symtabcmd = @ptrCast(
|
||||
*const std.macho.symtab_command,
|
||||
@alignCast(@alignOf(std.macho.symtab_command), ptr),
|
||||
);
|
||||
},
|
||||
else => {},
|
||||
}
|
||||
ptr = @alignCast(@alignOf(std.macho.load_command), ptr + lc.cmdsize);
|
||||
} else {
|
||||
return error.MissingDebugInfo;
|
||||
};
|
||||
}
|
||||
|
||||
if (segcmd == null or symtabcmd == null) return error.MissingDebugInfo;
|
||||
|
||||
// Parse symbols
|
||||
const strtab = @ptrCast(
|
||||
[*]const u8,
|
||||
hdr_base + symtabcmd.?.stroff,
|
||||
)[0 .. symtabcmd.?.strsize - 1 :0];
|
||||
const symtab = @ptrCast(
|
||||
[*]const macho.nlist_64,
|
||||
@alignCast(@alignOf(macho.nlist_64), hdr_base + symtabcmd.?.symoff),
|
||||
)[0..symtabcmd.?.nsyms];
|
||||
|
||||
// TODO handle tentative (common) symbols
|
||||
var addr_table = std.StringHashMap(u64).init(self.allocator());
|
||||
try addr_table.ensureTotalCapacity(@intCast(u32, symtab.len));
|
||||
for (symtab) |sym| {
|
||||
if (sym.n_strx == 0) continue;
|
||||
if (sym.undf() or sym.tentative() or sym.abs()) continue;
|
||||
const sym_name = mem.sliceTo(strtab[sym.n_strx..], 0);
|
||||
// TODO is it possible to have a symbol collision?
|
||||
addr_table.putAssumeCapacityNoClobber(sym_name, sym.n_value);
|
||||
}
|
||||
|
||||
var opt_debug_line: ?*const macho.section_64 = null;
|
||||
var opt_debug_info: ?*const macho.section_64 = null;
|
||||
@ -1275,8 +1352,8 @@ pub const ModuleDebugInfo = switch (native_os) {
|
||||
|
||||
const sections = @ptrCast(
|
||||
[*]const macho.section_64,
|
||||
@alignCast(@alignOf(macho.section_64), ptr + @sizeOf(std.macho.segment_command_64)),
|
||||
)[0..segcmd.nsects];
|
||||
@alignCast(@alignOf(macho.section_64), segptr + @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
|
||||
@ -1320,11 +1397,15 @@ pub const ModuleDebugInfo = switch (native_os) {
|
||||
};
|
||||
|
||||
try DW.openDwarfDebugInfo(&di, self.allocator());
|
||||
var info = OFileInfo{
|
||||
.di = di,
|
||||
.addr_table = addr_table,
|
||||
};
|
||||
|
||||
// Add the debug info to the cache
|
||||
try self.ofiles.putNoClobber(o_file_path, di);
|
||||
try self.ofiles.putNoClobber(o_file_path, info);
|
||||
|
||||
return di;
|
||||
return info;
|
||||
}
|
||||
|
||||
pub fn getSymbolAtAddress(self: *@This(), address: usize) !SymbolInfo {
|
||||
@ -1336,18 +1417,15 @@ pub const ModuleDebugInfo = switch (native_os) {
|
||||
// Find the .o file where this symbol is defined
|
||||
const symbol = machoSearchSymbols(self.symbols, relocated_address) orelse
|
||||
return SymbolInfo{};
|
||||
const addr_off = relocated_address - symbol.addr;
|
||||
|
||||
// Take the symbol name from the N_FUN STAB entry, we're going to
|
||||
// use it if we fail to find the DWARF infos
|
||||
const stab_symbol = mem.sliceTo(self.strings[symbol.nlist.n_strx..], 0);
|
||||
|
||||
if (symbol.ofile == null)
|
||||
return SymbolInfo{ .symbol_name = stab_symbol };
|
||||
|
||||
const o_file_path = mem.sliceTo(self.strings[symbol.ofile.?.n_strx..], 0);
|
||||
const stab_symbol = mem.sliceTo(self.strings[symbol.strx..], 0);
|
||||
const o_file_path = mem.sliceTo(self.strings[symbol.ofile..], 0);
|
||||
|
||||
// Check if its debug infos are already in the cache
|
||||
var o_file_di = self.ofiles.get(o_file_path) orelse
|
||||
var o_file_info = self.ofiles.get(o_file_path) orelse
|
||||
(self.loadOFile(o_file_path) catch |err| switch (err) {
|
||||
error.FileNotFound,
|
||||
error.MissingDebugInfo,
|
||||
@ -1357,19 +1435,22 @@ pub const ModuleDebugInfo = switch (native_os) {
|
||||
},
|
||||
else => return err,
|
||||
});
|
||||
const o_file_di = &o_file_info.di;
|
||||
|
||||
// Translate again the address, this time into an address inside the
|
||||
// .o file
|
||||
const relocated_address_o = relocated_address - symbol.reloc;
|
||||
const relocated_address_o = o_file_info.addr_table.get(stab_symbol) orelse return SymbolInfo{
|
||||
.symbol_name = "???",
|
||||
};
|
||||
|
||||
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) {
|
||||
.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) {
|
||||
.line_info = o_file_di.getLineNumberInfo(compile_unit.*, relocated_address_o + addr_off) catch |err| switch (err) {
|
||||
error.MissingDebugInfo, error.InvalidDebugInfo => null,
|
||||
else => return err,
|
||||
},
|
||||
|
||||
Loading…
x
Reference in New Issue
Block a user