authorgravatar for kcbanner@gmail.comCasey Banner <kcbanner@gmail.com> 2023-07-17 10:22:01-04:00
committergravatar for kcbanner@gmail.comCasey Banner <kcbanner@gmail.com> 2023-07-20 22:58:16-04:00
log97bda56306622784b2f2e4f036d817bbe5f2025e
treeecec2a45ed278bf105155049695526d9d32b4006
parent774dc2fdb75dc7f6b7e0bd2cfe947fffb9829ba1

macho: don't scan all eh_frame entries, instead follow the offset from the __unwind_info directly

3 files changed, 29 insertions(+), 15 deletions(-)

lib/std/debug.zig+1-5
......@@ -642,7 +642,7 @@ pub const StackIterator = struct {
642642 // __unwind_info is a requirement for unwinding on Darwin. It may fall back to DWARF, but unwinding
643643 // via DWARF before attempting to use the compact unwind info will produce incorrect results.
644644 if (module.unwind_info) |unwind_info| {
645 if (macho.unwindFrame(&unwind_state.dwarf_context, unwind_info, module.base_address)) |return_address| {
645 if (macho.unwindFrame(&unwind_state.dwarf_context, unwind_info, module.eh_frame, module.base_address)) |return_address| {
646646 return return_address;
647647 } else |err| {
648648 if (err != error.RequiresDWARFUnwind) return err;
......@@ -2026,10 +2026,6 @@ pub const ModuleDebugInfo = switch (native_os) {
20262026 };
20272027
20282028 try DW.openDwarfDebugInfo(&di, allocator);
2029
2030 // TODO: Don't actually scan everything, search on demand
2031 di.scanAllUnwindInfo(allocator, self.base_address) catch {};
2032
20332029 var info = OFileInfo{
20342030 .di = di,
20352031 .addr_table = addr_table,
lib/std/dwarf.zig+4-5
......@@ -686,7 +686,8 @@ pub const DwarfInfo = struct {
686686 pub const null_section_array = [_]?Section{null} ** num_sections;
687687
688688 endian: std.builtin.Endian,
689 sections: SectionArray,
689 sections: SectionArray = null_section_array,
690 is_macho: bool,
690691
691692 // Filled later by the initializer
692693 abbrev_table_list: std.ArrayListUnmanaged(AbbrevTableHeader) = .{},
......@@ -699,8 +700,6 @@ pub const DwarfInfo = struct {
699700 // Sorted by start_pc
700701 fde_list: std.ArrayListUnmanaged(FrameDescriptionEntry) = .{},
701702
702 is_macho: bool,
703
704703 pub fn section(di: DwarfInfo, dwarf_section: DwarfSection) ?[]const u8 {
705704 return if (di.sections[@intFromEnum(dwarf_section)]) |s| s.data else null;
706705 }
......@@ -1672,6 +1671,8 @@ pub const DwarfInfo = struct {
16721671 if (fde_offset >= frame_section.len) return error.MissingFDE;
16731672
16741673 var stream = io.fixedBufferStream(frame_section);
1674 try stream.seekTo(fde_offset);
1675
16751676 const fde_entry_header = try EntryHeader.read(&stream, dwarf_section, di.endian);
16761677 if (fde_entry_header.type != .fde) return error.MissingFDE;
16771678
......@@ -1701,8 +1702,6 @@ pub const DwarfInfo = struct {
17011702 builtin.cpu.arch.endian(),
17021703 );
17031704 } else if (di.eh_frame_hdr) |header| {
1704 std.debug.print("EH_FRAME_HDR\n", .{});
1705
17061705 const eh_frame_len = if (di.section(.eh_frame)) |eh_frame| eh_frame.len else null;
17071706 try header.findEntry(
17081707 context.isValidMemory,
lib/std/macho.zig+24-5
......@@ -2142,7 +2142,7 @@ fn dwarfRegNumber(unwind_reg_number: u3) !u8 {
21422142const dwarf = std.dwarf;
21432143const abi = dwarf.abi;
21442144
2145pub fn unwindFrame(context: *dwarf.UnwindContext, unwind_info: []const u8, module_base_address: usize) !usize {
2145pub fn unwindFrame(context: *dwarf.UnwindContext, unwind_info: []const u8, eh_frame: ?[]const u8, module_base_address: usize) !usize {
21462146 const header = mem.bytesAsValue(
21472147 unwind_info_section_header,
21482148 unwind_info[0..@sizeOf(unwind_info_section_header)],
......@@ -2396,7 +2396,9 @@ pub fn unwindFrame(context: *dwarf.UnwindContext, unwind_info: []const u8, modul
23962396
23972397 break :blk new_ip;
23982398 },
2399 .DWARF => return error.RequiresDWARFUnwind,
2399 .DWARF => {
2400 return unwindFrameDwarf(context, eh_frame orelse return error.MissingEhFrame, @intCast(encoding.value.x86_64.dwarf));
2401 },
24002402 },
24012403 .aarch64 => switch (encoding.mode.arm64) {
24022404 .OLD => return error.UnimplementedUnwindEncoding,
......@@ -2408,8 +2410,10 @@ pub fn unwindFrame(context: *dwarf.UnwindContext, unwind_info: []const u8, modul
24082410 (try abi.regValueNative(usize, context.thread_context, abi.spRegNum(reg_context), reg_context)).* = new_sp;
24092411 break :blk new_ip;
24102412 },
2411 .DWARF => return error.RequiresDWARFUnwind,
2412 .FRAME => {
2413 .DWARF => {
2414 return unwindFrameDwarf(context, eh_frame orelse return error.MissingEhFrame, @intCast(encoding.value.arm64.dwarf));
2415 },
2416 .FRAME => blk: {
24132417 const fp = (try abi.regValueNative(usize, context.thread_context, abi.fpRegNum(reg_context), reg_context)).*;
24142418 const new_sp = fp + 16;
24152419 const ip_ptr = fp + @sizeOf(usize);
......@@ -2453,7 +2457,7 @@ pub fn unwindFrame(context: *dwarf.UnwindContext, unwind_info: []const u8, modul
24532457 (try abi.regValueNative(usize, context.thread_context, abi.fpRegNum(reg_context), reg_context)).* = new_fp;
24542458 (try abi.regValueNative(usize, context.thread_context, abi.ipRegNum(), reg_context)).* = new_ip;
24552459
2456 return error.UnimplementedUnwindEncoding;
2460 break :blk new_ip;
24572461 },
24582462 },
24592463 else => return error.UnimplementedArch,
......@@ -2463,3 +2467,18 @@ pub fn unwindFrame(context: *dwarf.UnwindContext, unwind_info: []const u8, modul
24632467 if (context.pc > 0) context.pc -= 1;
24642468 return new_ip;
24652469}
2470
2471fn unwindFrameDwarf(context: *dwarf.UnwindContext, eh_frame: []const u8, fde_offset: usize) !usize {
2472 var di = dwarf.DwarfInfo{
2473 .endian = builtin.cpu.arch.endian(),
2474 .is_macho = true,
2475 };
2476 defer di.deinit(context.allocator);
2477
2478 di.sections[@intFromEnum(dwarf.DwarfSection.eh_frame)] = .{
2479 .data = eh_frame,
2480 .owned = false,
2481 };
2482
2483 return di.unwindFrame(context, fde_offset);
2484}