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zig/lib/std/dwarf.zig
Andrew Kelley 60722261fa std.debug: DWARFv5 fixes 
handle str_offsets_base and addr_base correctly.
handle data16
fix compilation on 32-bit hosts
remove stray debug print statement

closes #12120
2022-08-23 21:11:02 -07:00

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const builtin = @import("builtin");
const std = @import("std.zig");
const debug = std.debug;
const fs = std.fs;
const io = std.io;
const mem = std.mem;
const math = std.math;
const leb = @import("leb128.zig");
pub const TAG = @import("dwarf/TAG.zig");
pub const AT = @import("dwarf/AT.zig");
pub const OP = @import("dwarf/OP.zig");
pub const LANG = @import("dwarf/LANG.zig");
pub const FORM = @import("dwarf/FORM.zig");
pub const ATE = @import("dwarf/ATE.zig");
pub const LLE = struct {
pub const end_of_list = 0x00;
pub const base_addressx = 0x01;
pub const startx_endx = 0x02;
pub const startx_length = 0x03;
pub const offset_pair = 0x04;
pub const default_location = 0x05;
pub const base_address = 0x06;
pub const start_end = 0x07;
pub const start_length = 0x08;
};
pub const CFA = struct {
pub const advance_loc = 0x40;
pub const offset = 0x80;
pub const restore = 0xc0;
pub const nop = 0x00;
pub const set_loc = 0x01;
pub const advance_loc1 = 0x02;
pub const advance_loc2 = 0x03;
pub const advance_loc4 = 0x04;
pub const offset_extended = 0x05;
pub const restore_extended = 0x06;
pub const @"undefined" = 0x07;
pub const same_value = 0x08;
pub const register = 0x09;
pub const remember_state = 0x0a;
pub const restore_state = 0x0b;
pub const def_cfa = 0x0c;
pub const def_cfa_register = 0x0d;
pub const def_cfa_offset = 0x0e;
// DWARF 3.
pub const def_cfa_expression = 0x0f;
pub const expression = 0x10;
pub const offset_extended_sf = 0x11;
pub const def_cfa_sf = 0x12;
pub const def_cfa_offset_sf = 0x13;
pub const val_offset = 0x14;
pub const val_offset_sf = 0x15;
pub const val_expression = 0x16;
pub const lo_user = 0x1c;
pub const hi_user = 0x3f;
// SGI/MIPS specific.
pub const MIPS_advance_loc8 = 0x1d;
// GNU extensions.
pub const GNU_window_save = 0x2d;
pub const GNU_args_size = 0x2e;
pub const GNU_negative_offset_extended = 0x2f;
};
pub const CHILDREN = struct {
pub const no = 0x00;
pub const yes = 0x01;
};
pub const LNS = struct {
pub const extended_op = 0x00;
pub const copy = 0x01;
pub const advance_pc = 0x02;
pub const advance_line = 0x03;
pub const set_file = 0x04;
pub const set_column = 0x05;
pub const negate_stmt = 0x06;
pub const set_basic_block = 0x07;
pub const const_add_pc = 0x08;
pub const fixed_advance_pc = 0x09;
pub const set_prologue_end = 0x0a;
pub const set_epilogue_begin = 0x0b;
pub const set_isa = 0x0c;
};
pub const LNE = struct {
pub const end_sequence = 0x01;
pub const set_address = 0x02;
pub const define_file = 0x03;
pub const set_discriminator = 0x04;
pub const lo_user = 0x80;
pub const hi_user = 0xff;
};
pub const UT = struct {
pub const compile = 0x01;
pub const @"type" = 0x02;
pub const partial = 0x03;
pub const skeleton = 0x04;
pub const split_compile = 0x05;
pub const split_type = 0x06;
pub const lo_user = 0x80;
pub const hi_user = 0xff;
};
pub const LNCT = struct {
pub const path = 0x1;
pub const directory_index = 0x2;
pub const timestamp = 0x3;
pub const size = 0x4;
pub const MD5 = 0x5;
pub const lo_user = 0x2000;
pub const hi_user = 0x3fff;
};
pub const RLE = struct {
pub const end_of_list = 0x00;
pub const base_addressx = 0x01;
pub const startx_endx = 0x02;
pub const startx_length = 0x03;
pub const offset_pair = 0x04;
pub const base_address = 0x05;
pub const start_end = 0x06;
pub const start_length = 0x07;
};
pub const CC = enum(u8) {
normal = 0x1,
program = 0x2,
nocall = 0x3,
pass_by_reference = 0x4,
pass_by_value = 0x5,
lo_user = 0x40,
hi_user = 0xff,
GNU_renesas_sh = 0x40,
GNU_borland_fastcall_i386 = 0x41,
};
const PcRange = struct {
start: u64,
end: u64,
};
const Func = struct {
pc_range: ?PcRange,
name: ?[]const u8,
fn deinit(func: *Func, allocator: mem.Allocator) void {
if (func.name) |name| {
allocator.free(name);
}
}
};
const CompileUnit = struct {
version: u16,
is_64: bool,
die: *Die,
pc_range: ?PcRange,
str_offsets_base: usize,
addr_base: usize,
rnglists_base: usize,
loclists_base: usize,
};
const AbbrevTable = std.ArrayList(AbbrevTableEntry);
const AbbrevTableHeader = struct {
// offset from .debug_abbrev
offset: u64,
table: AbbrevTable,
fn deinit(header: *AbbrevTableHeader) void {
for (header.table.items) |*entry| {
entry.deinit();
}
header.table.deinit();
}
};
const AbbrevTableEntry = struct {
has_children: bool,
abbrev_code: u64,
tag_id: u64,
attrs: std.ArrayList(AbbrevAttr),
fn deinit(entry: *AbbrevTableEntry) void {
entry.attrs.deinit();
}
};
const AbbrevAttr = struct {
attr_id: u64,
form_id: u64,
/// Only valid if form_id is .implicit_const
payload: i64,
};
const FormValue = union(enum) {
Address: u64,
AddrOffset: usize,
Block: []u8,
Const: Constant,
ExprLoc: []u8,
Flag: bool,
SecOffset: u64,
Ref: u64,
RefAddr: u64,
String: []const u8,
StrPtr: u64,
StrOffset: usize,
LineStrPtr: u64,
LocListOffset: u64,
RangeListOffset: u64,
data16: [16]u8,
fn getString(fv: FormValue, di: DwarfInfo) ![]const u8 {
switch (fv) {
.String => |s| return s,
.StrPtr => |off| return di.getString(off),
.LineStrPtr => |off| return di.getLineString(off),
else => return badDwarf(),
}
}
fn getUInt(fv: FormValue, comptime U: type) !U {
switch (fv) {
.Const => |c| {
const int = try c.asUnsignedLe();
return math.cast(U, int) orelse return badDwarf();
},
.SecOffset => |x| return math.cast(U, x) orelse return badDwarf(),
else => return badDwarf(),
}
}
fn getData16(fv: FormValue) ![16]u8 {
switch (fv) {
.data16 => |d| return d,
else => return badDwarf(),
}
}
};
const Constant = struct {
payload: u64,
signed: bool,
fn asUnsignedLe(self: Constant) !u64 {
if (self.signed) return badDwarf();
return self.payload;
}
};
const Die = struct {
// Arena for Die's Attr's and FormValue's.
arena: std.heap.ArenaAllocator,
tag_id: u64,
has_children: bool,
attrs: std.ArrayListUnmanaged(Attr) = .{},
const Attr = struct {
id: u64,
value: FormValue,
};
fn deinit(self: *Die, allocator: mem.Allocator) void {
self.arena.deinit();
self.attrs.deinit(allocator);
}
fn getAttr(self: *const Die, id: u64) ?*const FormValue {
for (self.attrs.items) |*attr| {
if (attr.id == id) return &attr.value;
}
return null;
}
fn getAttrAddr(
self: *const Die,
di: *DwarfInfo,
id: u64,
compile_unit: CompileUnit,
) error{ InvalidDebugInfo, MissingDebugInfo }!u64 {
const form_value = self.getAttr(id) orelse return error.MissingDebugInfo;
return switch (form_value.*) {
FormValue.Address => |value| value,
FormValue.AddrOffset => |index| {
const debug_addr = di.debug_addr orelse return badDwarf();
// addr_base points to the first item after the header, however we
// need to read the header to know the size of each item. Empirically,
// it may disagree with is_64 on the compile unit.
// The header is 8 or 12 bytes depending on is_64.
if (compile_unit.addr_base < 8) return badDwarf();
const version = mem.readInt(u16, debug_addr[compile_unit.addr_base - 4 ..][0..2], di.endian);
if (version != 5) return badDwarf();
const addr_size = debug_addr[compile_unit.addr_base - 2];
const seg_size = debug_addr[compile_unit.addr_base - 1];
const byte_offset = compile_unit.addr_base + (addr_size + seg_size) * index;
if (byte_offset + addr_size > debug_addr.len) return badDwarf();
switch (addr_size) {
1 => return debug_addr[byte_offset],
2 => return mem.readInt(u16, debug_addr[byte_offset..][0..2], di.endian),
4 => return mem.readInt(u32, debug_addr[byte_offset..][0..4], di.endian),
8 => return mem.readInt(u64, debug_addr[byte_offset..][0..8], di.endian),
else => return badDwarf(),
}
},
else => error.InvalidDebugInfo,
};
}
fn getAttrSecOffset(self: *const Die, id: u64) !u64 {
const form_value = self.getAttr(id) orelse return error.MissingDebugInfo;
return form_value.getUInt(u64);
}
fn getAttrUnsignedLe(self: *const Die, id: u64) !u64 {
const form_value = self.getAttr(id) orelse return error.MissingDebugInfo;
return switch (form_value.*) {
FormValue.Const => |value| value.asUnsignedLe(),
else => error.InvalidDebugInfo,
};
}
fn getAttrRef(self: *const Die, id: u64) !u64 {
const form_value = self.getAttr(id) orelse return error.MissingDebugInfo;
return switch (form_value.*) {
FormValue.Ref => |value| value,
else => error.InvalidDebugInfo,
};
}
pub fn getAttrString(
self: *const Die,
di: *DwarfInfo,
id: u64,
opt_str: ?[]const u8,
compile_unit: CompileUnit,
) error{ InvalidDebugInfo, MissingDebugInfo }![]const u8 {
const form_value = self.getAttr(id) orelse return error.MissingDebugInfo;
switch (form_value.*) {
FormValue.String => |value| return value,
FormValue.StrPtr => |offset| return di.getString(offset),
FormValue.StrOffset => |index| {
const debug_str_offsets = di.debug_str_offsets orelse return badDwarf();
if (compile_unit.str_offsets_base == 0) return badDwarf();
if (compile_unit.is_64) {
const byte_offset = compile_unit.str_offsets_base + 8 * index;
if (byte_offset + 8 > debug_str_offsets.len) return badDwarf();
const offset = mem.readInt(u64, debug_str_offsets[byte_offset..][0..8], di.endian);
return getStringGeneric(opt_str, offset);
} else {
const byte_offset = compile_unit.str_offsets_base + 4 * index;
if (byte_offset + 4 > debug_str_offsets.len) return badDwarf();
const offset = mem.readInt(u32, debug_str_offsets[byte_offset..][0..4], di.endian);
return getStringGeneric(opt_str, offset);
}
},
FormValue.LineStrPtr => |offset| return di.getLineString(offset),
else => return badDwarf(),
}
}
};
const FileEntry = struct {
path: []const u8,
dir_index: u32 = 0,
mtime: u64 = 0,
size: u64 = 0,
md5: [16]u8 = [1]u8{0} ** 16,
};
const LineNumberProgram = struct {
address: u64,
file: usize,
line: i64,
column: u64,
version: u16,
is_stmt: bool,
basic_block: bool,
end_sequence: bool,
default_is_stmt: bool,
target_address: u64,
include_dirs: []const FileEntry,
prev_valid: bool,
prev_address: u64,
prev_file: usize,
prev_line: i64,
prev_column: u64,
prev_is_stmt: bool,
prev_basic_block: bool,
prev_end_sequence: bool,
// Reset the state machine following the DWARF specification
pub fn reset(self: *LineNumberProgram) void {
self.address = 0;
self.file = 1;
self.line = 1;
self.column = 0;
self.is_stmt = self.default_is_stmt;
self.basic_block = false;
self.end_sequence = false;
// Invalidate all the remaining fields
self.prev_valid = false;
self.prev_address = 0;
self.prev_file = undefined;
self.prev_line = undefined;
self.prev_column = undefined;
self.prev_is_stmt = undefined;
self.prev_basic_block = undefined;
self.prev_end_sequence = undefined;
}
pub fn init(
is_stmt: bool,
include_dirs: []const FileEntry,
target_address: u64,
version: u16,
) LineNumberProgram {
return LineNumberProgram{
.address = 0,
.file = 1,
.line = 1,
.column = 0,
.version = version,
.is_stmt = is_stmt,
.basic_block = false,
.end_sequence = false,
.include_dirs = include_dirs,
.default_is_stmt = is_stmt,
.target_address = target_address,
.prev_valid = false,
.prev_address = 0,
.prev_file = undefined,
.prev_line = undefined,
.prev_column = undefined,
.prev_is_stmt = undefined,
.prev_basic_block = undefined,
.prev_end_sequence = undefined,
};
}
pub fn checkLineMatch(
self: *LineNumberProgram,
allocator: mem.Allocator,
file_entries: []const FileEntry,
) !?debug.LineInfo {
if (self.prev_valid and
self.target_address >= self.prev_address and
self.target_address < self.address)
{
const file_index = if (self.version >= 5) self.prev_file else i: {
if (self.prev_file == 0) return missingDwarf();
break :i self.prev_file - 1;
};
if (file_index >= file_entries.len) return badDwarf();
const file_entry = &file_entries[file_index];
if (file_entry.dir_index >= self.include_dirs.len) return badDwarf();
const dir_name = self.include_dirs[file_entry.dir_index].path;
const file_name = try fs.path.join(allocator, &[_][]const u8{
dir_name, file_entry.path,
});
return debug.LineInfo{
.line = if (self.prev_line >= 0) @intCast(u64, self.prev_line) else 0,
.column = self.prev_column,
.file_name = file_name,
};
}
self.prev_valid = true;
self.prev_address = self.address;
self.prev_file = self.file;
self.prev_line = self.line;
self.prev_column = self.column;
self.prev_is_stmt = self.is_stmt;
self.prev_basic_block = self.basic_block;
self.prev_end_sequence = self.end_sequence;
return null;
}
};
fn readUnitLength(in_stream: anytype, endian: std.builtin.Endian, is_64: *bool) !u64 {
const first_32_bits = try in_stream.readInt(u32, endian);
is_64.* = (first_32_bits == 0xffffffff);
if (is_64.*) {
return in_stream.readInt(u64, endian);
} else {
if (first_32_bits >= 0xfffffff0) return badDwarf();
// TODO this cast should not be needed
return @as(u64, first_32_bits);
}
}
// TODO the nosuspends here are workarounds
fn readAllocBytes(allocator: mem.Allocator, in_stream: anytype, size: usize) ![]u8 {
const buf = try allocator.alloc(u8, size);
errdefer allocator.free(buf);
if ((try nosuspend in_stream.read(buf)) < size) return error.EndOfFile;
return buf;
}
// TODO the nosuspends here are workarounds
fn readAddress(in_stream: anytype, endian: std.builtin.Endian, is_64: bool) !u64 {
return nosuspend if (is_64)
try in_stream.readInt(u64, endian)
else
@as(u64, try in_stream.readInt(u32, endian));
}
fn parseFormValueBlockLen(allocator: mem.Allocator, in_stream: anytype, size: usize) !FormValue {
const buf = try readAllocBytes(allocator, in_stream, size);
return FormValue{ .Block = buf };
}
// TODO the nosuspends here are workarounds
fn parseFormValueBlock(allocator: mem.Allocator, in_stream: anytype, endian: std.builtin.Endian, size: usize) !FormValue {
const block_len = try nosuspend in_stream.readVarInt(usize, endian, size);
return parseFormValueBlockLen(allocator, in_stream, block_len);
}
fn parseFormValueConstant(in_stream: anytype, signed: bool, endian: std.builtin.Endian, comptime size: i32) !FormValue {
// TODO: Please forgive me, I've worked around zig not properly spilling some intermediate values here.
// `nosuspend` should be removed from all the function calls once it is fixed.
return FormValue{
.Const = Constant{
.signed = signed,
.payload = switch (size) {
1 => try nosuspend in_stream.readInt(u8, endian),
2 => try nosuspend in_stream.readInt(u16, endian),
4 => try nosuspend in_stream.readInt(u32, endian),
8 => try nosuspend in_stream.readInt(u64, endian),
-1 => blk: {
if (signed) {
const x = try nosuspend leb.readILEB128(i64, in_stream);
break :blk @bitCast(u64, x);
} else {
const x = try nosuspend leb.readULEB128(u64, in_stream);
break :blk x;
}
},
else => @compileError("Invalid size"),
},
},
};
}
// TODO the nosuspends here are workarounds
fn parseFormValueRef(in_stream: anytype, endian: std.builtin.Endian, size: i32) !FormValue {
return FormValue{
.Ref = switch (size) {
1 => try nosuspend in_stream.readInt(u8, endian),
2 => try nosuspend in_stream.readInt(u16, endian),
4 => try nosuspend in_stream.readInt(u32, endian),
8 => try nosuspend in_stream.readInt(u64, endian),
-1 => try nosuspend leb.readULEB128(u64, in_stream),
else => unreachable,
},
};
}
// TODO the nosuspends here are workarounds
fn parseFormValue(allocator: mem.Allocator, in_stream: anytype, form_id: u64, endian: std.builtin.Endian, is_64: bool) anyerror!FormValue {
return switch (form_id) {
FORM.addr => FormValue{ .Address = try readAddress(in_stream, endian, @sizeOf(usize) == 8) },
FORM.addrx1 => return FormValue{ .AddrOffset = try in_stream.readInt(u8, endian) },
FORM.addrx2 => return FormValue{ .AddrOffset = try in_stream.readInt(u16, endian) },
FORM.addrx3 => return FormValue{ .AddrOffset = try in_stream.readInt(u24, endian) },
FORM.addrx4 => return FormValue{ .AddrOffset = try in_stream.readInt(u32, endian) },
FORM.addrx => return FormValue{ .AddrOffset = try nosuspend leb.readULEB128(usize, in_stream) },
FORM.block1 => parseFormValueBlock(allocator, in_stream, endian, 1),
FORM.block2 => parseFormValueBlock(allocator, in_stream, endian, 2),
FORM.block4 => parseFormValueBlock(allocator, in_stream, endian, 4),
FORM.block => {
const block_len = try nosuspend leb.readULEB128(usize, in_stream);
return parseFormValueBlockLen(allocator, in_stream, block_len);
},
FORM.data1 => parseFormValueConstant(in_stream, false, endian, 1),
FORM.data2 => parseFormValueConstant(in_stream, false, endian, 2),
FORM.data4 => parseFormValueConstant(in_stream, false, endian, 4),
FORM.data8 => parseFormValueConstant(in_stream, false, endian, 8),
FORM.data16 => {
var buf: [16]u8 = undefined;
if ((try nosuspend in_stream.readAll(&buf)) < 16) return error.EndOfFile;
return FormValue{ .data16 = buf };
},
FORM.udata, FORM.sdata => {
const signed = form_id == FORM.sdata;
return parseFormValueConstant(in_stream, signed, endian, -1);
},
FORM.exprloc => {
const size = try nosuspend leb.readULEB128(usize, in_stream);
const buf = try readAllocBytes(allocator, in_stream, size);
return FormValue{ .ExprLoc = buf };
},
FORM.flag => FormValue{ .Flag = (try nosuspend in_stream.readByte()) != 0 },
FORM.flag_present => FormValue{ .Flag = true },
FORM.sec_offset => FormValue{ .SecOffset = try readAddress(in_stream, endian, is_64) },
FORM.ref1 => parseFormValueRef(in_stream, endian, 1),
FORM.ref2 => parseFormValueRef(in_stream, endian, 2),
FORM.ref4 => parseFormValueRef(in_stream, endian, 4),
FORM.ref8 => parseFormValueRef(in_stream, endian, 8),
FORM.ref_udata => parseFormValueRef(in_stream, endian, -1),
FORM.ref_addr => FormValue{ .RefAddr = try readAddress(in_stream, endian, is_64) },
FORM.ref_sig8 => FormValue{ .Ref = try nosuspend in_stream.readInt(u64, endian) },
FORM.string => FormValue{ .String = try in_stream.readUntilDelimiterAlloc(allocator, 0, math.maxInt(usize)) },
FORM.strp => FormValue{ .StrPtr = try readAddress(in_stream, endian, is_64) },
FORM.strx1 => return FormValue{ .StrOffset = try in_stream.readInt(u8, endian) },
FORM.strx2 => return FormValue{ .StrOffset = try in_stream.readInt(u16, endian) },
FORM.strx3 => return FormValue{ .StrOffset = try in_stream.readInt(u24, endian) },
FORM.strx4 => return FormValue{ .StrOffset = try in_stream.readInt(u32, endian) },
FORM.strx => return FormValue{ .StrOffset = try nosuspend leb.readULEB128(usize, in_stream) },
FORM.line_strp => FormValue{ .LineStrPtr = try readAddress(in_stream, endian, is_64) },
FORM.indirect => {
const child_form_id = try nosuspend leb.readULEB128(u64, in_stream);
if (builtin.zig_backend != .stage1) {
return parseFormValue(allocator, in_stream, child_form_id, endian, is_64);
}
const F = @TypeOf(async parseFormValue(allocator, in_stream, child_form_id, endian, is_64));
var frame = try allocator.create(F);
defer allocator.destroy(frame);
return await @asyncCall(frame, {}, parseFormValue, .{ allocator, in_stream, child_form_id, endian, is_64 });
},
FORM.implicit_const => FormValue{ .Const = Constant{ .signed = true, .payload = undefined } },
FORM.loclistx => return FormValue{ .LocListOffset = try nosuspend leb.readULEB128(u64, in_stream) },
FORM.rnglistx => return FormValue{ .RangeListOffset = try nosuspend leb.readULEB128(u64, in_stream) },
else => {
//std.debug.print("unrecognized form id: {x}\n", .{form_id});
return badDwarf();
},
};
}
fn getAbbrevTableEntry(abbrev_table: *const AbbrevTable, abbrev_code: u64) ?*const AbbrevTableEntry {
for (abbrev_table.items) |*table_entry| {
if (table_entry.abbrev_code == abbrev_code) return table_entry;
}
return null;
}
pub const DwarfInfo = struct {
endian: std.builtin.Endian,
// No memory is owned by the DwarfInfo
debug_info: []const u8,
debug_abbrev: []const u8,
debug_str: []const u8,
debug_str_offsets: ?[]const u8,
debug_line: []const u8,
debug_line_str: ?[]const u8,
debug_ranges: ?[]const u8,
debug_loclists: ?[]const u8,
debug_rnglists: ?[]const u8,
debug_addr: ?[]const u8,
debug_names: ?[]const u8,
debug_frame: ?[]const u8,
// Filled later by the initializer
abbrev_table_list: std.ArrayListUnmanaged(AbbrevTableHeader) = .{},
compile_unit_list: std.ArrayListUnmanaged(CompileUnit) = .{},
func_list: std.ArrayListUnmanaged(Func) = .{},
pub fn deinit(di: *DwarfInfo, allocator: mem.Allocator) void {
for (di.abbrev_table_list.items) |*abbrev| {
abbrev.deinit();
}
di.abbrev_table_list.deinit(allocator);
for (di.compile_unit_list.items) |*cu| {
cu.die.deinit(allocator);
allocator.destroy(cu.die);
}
di.compile_unit_list.deinit(allocator);
for (di.func_list.items) |*func| {
func.deinit(allocator);
}
di.func_list.deinit(allocator);
}
pub fn getSymbolName(di: *DwarfInfo, address: u64) ?[]const u8 {
for (di.func_list.items) |*func| {
if (func.pc_range) |range| {
if (address >= range.start and address < range.end) {
return func.name;
}
}
}
return null;
}
fn scanAllFunctions(di: *DwarfInfo, allocator: mem.Allocator) !void {
var stream = io.fixedBufferStream(di.debug_info);
const in = stream.reader();
const seekable = &stream.seekableStream();
var this_unit_offset: u64 = 0;
var tmp_arena = std.heap.ArenaAllocator.init(allocator);
defer tmp_arena.deinit();
const arena = tmp_arena.allocator();
while (this_unit_offset < try seekable.getEndPos()) {
try seekable.seekTo(this_unit_offset);
var is_64: bool = undefined;
const unit_length = try readUnitLength(in, di.endian, &is_64);
if (unit_length == 0) return;
const next_offset = unit_length + (if (is_64) @as(usize, 12) else @as(usize, 4));
const version = try in.readInt(u16, di.endian);
if (version < 2 or version > 5) return badDwarf();
var address_size: u8 = undefined;
var debug_abbrev_offset: u64 = undefined;
if (version >= 5) {
const unit_type = try in.readInt(u8, di.endian);
if (unit_type != UT.compile) return badDwarf();
address_size = try in.readByte();
debug_abbrev_offset = if (is_64)
try in.readInt(u64, di.endian)
else
try in.readInt(u32, di.endian);
} else {
debug_abbrev_offset = if (is_64)
try in.readInt(u64, di.endian)
else
try in.readInt(u32, di.endian);
address_size = try in.readByte();
}
if (address_size != @sizeOf(usize)) return badDwarf();
const compile_unit_pos = try seekable.getPos();
const abbrev_table = try di.getAbbrevTable(allocator, debug_abbrev_offset);
try seekable.seekTo(compile_unit_pos);
const next_unit_pos = this_unit_offset + next_offset;
var compile_unit: CompileUnit = undefined;
while ((try seekable.getPos()) < next_unit_pos) {
var die_obj = (try di.parseDie(arena, in, abbrev_table, is_64)) orelse continue;
const after_die_offset = try seekable.getPos();
switch (die_obj.tag_id) {
TAG.compile_unit => {
compile_unit = .{
.version = version,
.is_64 = is_64,
.die = &die_obj,
.pc_range = null,
.str_offsets_base = if (die_obj.getAttr(AT.str_offsets_base)) |fv| try fv.getUInt(usize) else 0,
.addr_base = if (die_obj.getAttr(AT.addr_base)) |fv| try fv.getUInt(usize) else 0,
.rnglists_base = if (die_obj.getAttr(AT.rnglists_base)) |fv| try fv.getUInt(usize) else 0,
.loclists_base = if (die_obj.getAttr(AT.loclists_base)) |fv| try fv.getUInt(usize) else 0,
};
},
TAG.subprogram, TAG.inlined_subroutine, TAG.subroutine, TAG.entry_point => {
const fn_name = x: {
var depth: i32 = 3;
var this_die_obj = die_obj;
// Prevent endless loops
while (depth > 0) : (depth -= 1) {
if (this_die_obj.getAttr(AT.name)) |_| {
const name = try this_die_obj.getAttrString(di, AT.name, di.debug_str, compile_unit);
break :x try allocator.dupe(u8, name);
} else if (this_die_obj.getAttr(AT.abstract_origin)) |_| {
// Follow the DIE it points to and repeat
const ref_offset = try this_die_obj.getAttrRef(AT.abstract_origin);
if (ref_offset > next_offset) return badDwarf();
try seekable.seekTo(this_unit_offset + ref_offset);
this_die_obj = (try di.parseDie(
arena,
in,
abbrev_table,
is_64,
)) orelse return badDwarf();
} else if (this_die_obj.getAttr(AT.specification)) |_| {
// Follow the DIE it points to and repeat
const ref_offset = try this_die_obj.getAttrRef(AT.specification);
if (ref_offset > next_offset) return badDwarf();
try seekable.seekTo(this_unit_offset + ref_offset);
this_die_obj = (try di.parseDie(
arena,
in,
abbrev_table,
is_64,
)) orelse return badDwarf();
} else {
break :x null;
}
}
break :x null;
};
const pc_range = x: {
if (die_obj.getAttrAddr(di, AT.low_pc, compile_unit)) |low_pc| {
if (die_obj.getAttr(AT.high_pc)) |high_pc_value| {
const pc_end = switch (high_pc_value.*) {
FormValue.Address => |value| value,
FormValue.Const => |value| b: {
const offset = try value.asUnsignedLe();
break :b (low_pc + offset);
},
else => return badDwarf(),
};
break :x PcRange{
.start = low_pc,
.end = pc_end,
};
} else {
break :x null;
}
} else |err| {
if (err != error.MissingDebugInfo) return err;
break :x null;
}
};
try di.func_list.append(allocator, Func{
.name = fn_name,
.pc_range = pc_range,
});
},
else => {},
}
try seekable.seekTo(after_die_offset);
}
this_unit_offset += next_offset;
}
}
fn scanAllCompileUnits(di: *DwarfInfo, allocator: mem.Allocator) !void {
var stream = io.fixedBufferStream(di.debug_info);
const in = &stream.reader();
const seekable = &stream.seekableStream();
var this_unit_offset: u64 = 0;
while (this_unit_offset < try seekable.getEndPos()) {
try seekable.seekTo(this_unit_offset);
var is_64: bool = undefined;
const unit_length = try readUnitLength(in, di.endian, &is_64);
if (unit_length == 0) return;
const next_offset = unit_length + (if (is_64) @as(usize, 12) else @as(usize, 4));
const version = try in.readInt(u16, di.endian);
if (version < 2 or version > 5) return badDwarf();
var address_size: u8 = undefined;
var debug_abbrev_offset: u64 = undefined;
if (version >= 5) {
const unit_type = try in.readInt(u8, di.endian);
if (unit_type != UT.compile) return badDwarf();
address_size = try in.readByte();
debug_abbrev_offset = if (is_64)
try in.readInt(u64, di.endian)
else
try in.readInt(u32, di.endian);
} else {
debug_abbrev_offset = if (is_64)
try in.readInt(u64, di.endian)
else
try in.readInt(u32, di.endian);
address_size = try in.readByte();
}
if (address_size != @sizeOf(usize)) return badDwarf();
const compile_unit_pos = try seekable.getPos();
const abbrev_table = try di.getAbbrevTable(allocator, debug_abbrev_offset);
try seekable.seekTo(compile_unit_pos);
const compile_unit_die = try allocator.create(Die);
errdefer allocator.destroy(compile_unit_die);
compile_unit_die.* = (try di.parseDie(allocator, in, abbrev_table, is_64)) orelse
return badDwarf();
if (compile_unit_die.tag_id != TAG.compile_unit) return badDwarf();
var compile_unit: CompileUnit = .{
.version = version,
.is_64 = is_64,
.pc_range = null,
.die = compile_unit_die,
.str_offsets_base = if (compile_unit_die.getAttr(AT.str_offsets_base)) |fv| try fv.getUInt(usize) else 0,
.addr_base = if (compile_unit_die.getAttr(AT.addr_base)) |fv| try fv.getUInt(usize) else 0,
.rnglists_base = if (compile_unit_die.getAttr(AT.rnglists_base)) |fv| try fv.getUInt(usize) else 0,
.loclists_base = if (compile_unit_die.getAttr(AT.loclists_base)) |fv| try fv.getUInt(usize) else 0,
};
compile_unit.pc_range = x: {
if (compile_unit_die.getAttrAddr(di, AT.low_pc, compile_unit)) |low_pc| {
if (compile_unit_die.getAttr(AT.high_pc)) |high_pc_value| {
const pc_end = switch (high_pc_value.*) {
FormValue.Address => |value| value,
FormValue.Const => |value| b: {
const offset = try value.asUnsignedLe();
break :b (low_pc + offset);
},
else => return badDwarf(),
};
break :x PcRange{
.start = low_pc,
.end = pc_end,
};
} else {
break :x null;
}
} else |err| {
if (err != error.MissingDebugInfo) return err;
break :x null;
}
};
try di.compile_unit_list.append(allocator, compile_unit);
this_unit_offset += next_offset;
}
}
pub fn findCompileUnit(di: *DwarfInfo, target_address: u64) !*const CompileUnit {
for (di.compile_unit_list.items) |*compile_unit| {
if (compile_unit.pc_range) |range| {
if (target_address >= range.start and target_address < range.end) return compile_unit;
}
if (di.debug_ranges) |debug_ranges| {
if (compile_unit.die.getAttrSecOffset(AT.ranges)) |ranges_offset| {
var stream = io.fixedBufferStream(debug_ranges);
const in = &stream.reader();
const seekable = &stream.seekableStream();
// All the addresses in the list are relative to the value
// specified by DW_AT.low_pc or to some other value encoded
// in the list itself.
// If no starting value is specified use zero.
var base_address = compile_unit.die.getAttrAddr(di, AT.low_pc, compile_unit.*) catch |err| switch (err) {
error.MissingDebugInfo => @as(u64, 0), // TODO https://github.com/ziglang/zig/issues/11135
else => return err,
};
try seekable.seekTo(ranges_offset);
while (true) {
const begin_addr = try in.readInt(usize, di.endian);
const end_addr = try in.readInt(usize, di.endian);
if (begin_addr == 0 and end_addr == 0) {
break;
}
// This entry selects a new value for the base address
if (begin_addr == math.maxInt(usize)) {
base_address = end_addr;
continue;
}
if (target_address >= base_address + begin_addr and target_address < base_address + end_addr) {
return compile_unit;
}
}
} else |err| {
if (err != error.MissingDebugInfo) return err;
continue;
}
}
}
return missingDwarf();
}
/// Gets an already existing AbbrevTable given the abbrev_offset, or if not found,
/// seeks in the stream and parses it.
fn getAbbrevTable(di: *DwarfInfo, allocator: mem.Allocator, abbrev_offset: u64) !*const AbbrevTable {
for (di.abbrev_table_list.items) |*header| {
if (header.offset == abbrev_offset) {
return &header.table;
}
}
try di.abbrev_table_list.append(allocator, AbbrevTableHeader{
.offset = abbrev_offset,
.table = try di.parseAbbrevTable(allocator, abbrev_offset),
});
return &di.abbrev_table_list.items[di.abbrev_table_list.items.len - 1].table;
}
fn parseAbbrevTable(di: *DwarfInfo, allocator: mem.Allocator, offset: u64) !AbbrevTable {
var stream = io.fixedBufferStream(di.debug_abbrev);
const in = &stream.reader();
const seekable = &stream.seekableStream();
try seekable.seekTo(offset);
var result = AbbrevTable.init(allocator);
errdefer {
for (result.items) |*entry| {
entry.attrs.deinit();
}
result.deinit();
}
while (true) {
const abbrev_code = try leb.readULEB128(u64, in);
if (abbrev_code == 0) return result;
try result.append(AbbrevTableEntry{
.abbrev_code = abbrev_code,
.tag_id = try leb.readULEB128(u64, in),
.has_children = (try in.readByte()) == CHILDREN.yes,
.attrs = std.ArrayList(AbbrevAttr).init(allocator),
});
const attrs = &result.items[result.items.len - 1].attrs;
while (true) {
const attr_id = try leb.readULEB128(u64, in);
const form_id = try leb.readULEB128(u64, in);
if (attr_id == 0 and form_id == 0) break;
// DW_FORM_implicit_const stores its value immediately after the attribute pair :(
const payload = if (form_id == FORM.implicit_const) try leb.readILEB128(i64, in) else undefined;
try attrs.append(AbbrevAttr{
.attr_id = attr_id,
.form_id = form_id,
.payload = payload,
});
}
}
}
fn parseDie(
di: *DwarfInfo,
allocator: mem.Allocator,
in_stream: anytype,
abbrev_table: *const AbbrevTable,
is_64: bool,
) !?Die {
const abbrev_code = try leb.readULEB128(u64, in_stream);
if (abbrev_code == 0) return null;
const table_entry = getAbbrevTableEntry(abbrev_table, abbrev_code) orelse return badDwarf();
var result = Die{
// Lives as long as the Die.
.arena = std.heap.ArenaAllocator.init(allocator),
.tag_id = table_entry.tag_id,
.has_children = table_entry.has_children,
};
try result.attrs.resize(allocator, table_entry.attrs.items.len);
for (table_entry.attrs.items) |attr, i| {
result.attrs.items[i] = Die.Attr{
.id = attr.attr_id,
.value = try parseFormValue(
result.arena.allocator(),
in_stream,
attr.form_id,
di.endian,
is_64,
),
};
if (attr.form_id == FORM.implicit_const) {
result.attrs.items[i].value.Const.payload = @bitCast(u64, attr.payload);
}
}
return result;
}
pub fn getLineNumberInfo(
di: *DwarfInfo,
allocator: mem.Allocator,
compile_unit: CompileUnit,
target_address: u64,
) !debug.LineInfo {
var stream = io.fixedBufferStream(di.debug_line);
const in = &stream.reader();
const seekable = &stream.seekableStream();
const compile_unit_cwd = try compile_unit.die.getAttrString(di, AT.comp_dir, di.debug_line_str, compile_unit);
const line_info_offset = try compile_unit.die.getAttrSecOffset(AT.stmt_list);
try seekable.seekTo(line_info_offset);
var is_64: bool = undefined;
const unit_length = try readUnitLength(in, di.endian, &is_64);
if (unit_length == 0) {
return missingDwarf();
}
const next_offset = unit_length + (if (is_64) @as(usize, 12) else @as(usize, 4));
const version = try in.readInt(u16, di.endian);
if (version < 2) return badDwarf();
var addr_size: u8 = if (is_64) 8 else 4;
var seg_size: u8 = 0;
if (version >= 5) {
addr_size = try in.readByte();
seg_size = try in.readByte();
}
const prologue_length = if (is_64) try in.readInt(u64, di.endian) else try in.readInt(u32, di.endian);
const prog_start_offset = (try seekable.getPos()) + prologue_length;
const minimum_instruction_length = try in.readByte();
if (minimum_instruction_length == 0) return badDwarf();
if (version >= 4) {
// maximum_operations_per_instruction
_ = try in.readByte();
}
const default_is_stmt = (try in.readByte()) != 0;
const line_base = try in.readByteSigned();
const line_range = try in.readByte();
if (line_range == 0) return badDwarf();
const opcode_base = try in.readByte();
const standard_opcode_lengths = try allocator.alloc(u8, opcode_base - 1);
defer allocator.free(standard_opcode_lengths);
{
var i: usize = 0;
while (i < opcode_base - 1) : (i += 1) {
standard_opcode_lengths[i] = try in.readByte();
}
}
var tmp_arena = std.heap.ArenaAllocator.init(allocator);
defer tmp_arena.deinit();
const arena = tmp_arena.allocator();
var include_directories = std.ArrayList(FileEntry).init(arena);
var file_entries = std.ArrayList(FileEntry).init(arena);
if (version < 5) {
try include_directories.append(.{ .path = compile_unit_cwd });
while (true) {
const dir = try in.readUntilDelimiterAlloc(arena, 0, math.maxInt(usize));
if (dir.len == 0) break;
try include_directories.append(.{ .path = dir });
}
while (true) {
const file_name = try in.readUntilDelimiterAlloc(arena, 0, math.maxInt(usize));
if (file_name.len == 0) break;
const dir_index = try leb.readULEB128(u32, in);
const mtime = try leb.readULEB128(u64, in);
const size = try leb.readULEB128(u64, in);
try file_entries.append(FileEntry{
.path = file_name,
.dir_index = dir_index,
.mtime = mtime,
.size = size,
});
}
} else {
const FileEntFmt = struct {
content_type_code: u8,
form_code: u16,
};
{
var dir_ent_fmt_buf: [10]FileEntFmt = undefined;
const directory_entry_format_count = try in.readByte();
if (directory_entry_format_count > dir_ent_fmt_buf.len) return badDwarf();
for (dir_ent_fmt_buf[0..directory_entry_format_count]) |*ent_fmt| {
ent_fmt.* = .{
.content_type_code = try leb.readULEB128(u8, in),
.form_code = try leb.readULEB128(u16, in),
};
}
const directories_count = try leb.readULEB128(usize, in);
try include_directories.ensureUnusedCapacity(directories_count);
{
var i: usize = 0;
while (i < directories_count) : (i += 1) {
var e: FileEntry = .{ .path = &.{} };
for (dir_ent_fmt_buf[0..directory_entry_format_count]) |ent_fmt| {
const form_value = try parseFormValue(
arena,
in,
ent_fmt.form_code,
di.endian,
is_64,
);
switch (ent_fmt.content_type_code) {
LNCT.path => e.path = try form_value.getString(di.*),
LNCT.directory_index => e.dir_index = try form_value.getUInt(u32),
LNCT.timestamp => e.mtime = try form_value.getUInt(u64),
LNCT.size => e.size = try form_value.getUInt(u64),
LNCT.MD5 => e.md5 = try form_value.getData16(),
else => continue,
}
}
include_directories.appendAssumeCapacity(e);
}
}
}
var file_ent_fmt_buf: [10]FileEntFmt = undefined;
const file_name_entry_format_count = try in.readByte();
if (file_name_entry_format_count > file_ent_fmt_buf.len) return badDwarf();
for (file_ent_fmt_buf[0..file_name_entry_format_count]) |*ent_fmt| {
ent_fmt.* = .{
.content_type_code = try leb.readULEB128(u8, in),
.form_code = try leb.readULEB128(u16, in),
};
}
const file_names_count = try leb.readULEB128(usize, in);
try file_entries.ensureUnusedCapacity(file_names_count);
{
var i: usize = 0;
while (i < file_names_count) : (i += 1) {
var e: FileEntry = .{ .path = &.{} };
for (file_ent_fmt_buf[0..file_name_entry_format_count]) |ent_fmt| {
const form_value = try parseFormValue(
arena,
in,
ent_fmt.form_code,
di.endian,
is_64,
);
switch (ent_fmt.content_type_code) {
LNCT.path => e.path = try form_value.getString(di.*),
LNCT.directory_index => e.dir_index = try form_value.getUInt(u32),
LNCT.timestamp => e.mtime = try form_value.getUInt(u64),
LNCT.size => e.size = try form_value.getUInt(u64),
LNCT.MD5 => e.md5 = try form_value.getData16(),
else => continue,
}
}
file_entries.appendAssumeCapacity(e);
}
}
}
var prog = LineNumberProgram.init(
default_is_stmt,
include_directories.items,
target_address,
version,
);
try seekable.seekTo(prog_start_offset);
const next_unit_pos = line_info_offset + next_offset;
while ((try seekable.getPos()) < next_unit_pos) {
const opcode = try in.readByte();
if (opcode == LNS.extended_op) {
const op_size = try leb.readULEB128(u64, in);
if (op_size < 1) return badDwarf();
var sub_op = try in.readByte();
switch (sub_op) {
LNE.end_sequence => {
prog.end_sequence = true;
if (try prog.checkLineMatch(allocator, file_entries.items)) |info| return info;
prog.reset();
},
LNE.set_address => {
const addr = try in.readInt(usize, di.endian);
prog.address = addr;
},
LNE.define_file => {
const path = try in.readUntilDelimiterAlloc(arena, 0, math.maxInt(usize));
const dir_index = try leb.readULEB128(u32, in);
const mtime = try leb.readULEB128(u64, in);
const size = try leb.readULEB128(u64, in);
try file_entries.append(FileEntry{
.path = path,
.dir_index = dir_index,
.mtime = mtime,
.size = size,
});
},
else => {
const fwd_amt = math.cast(isize, op_size - 1) orelse return badDwarf();
try seekable.seekBy(fwd_amt);
},
}
} else if (opcode >= opcode_base) {
// special opcodes
const adjusted_opcode = opcode - opcode_base;
const inc_addr = minimum_instruction_length * (adjusted_opcode / line_range);
const inc_line = @as(i32, line_base) + @as(i32, adjusted_opcode % line_range);
prog.line += inc_line;
prog.address += inc_addr;
if (try prog.checkLineMatch(allocator, file_entries.items)) |info| return info;
prog.basic_block = false;
} else {
switch (opcode) {
LNS.copy => {
if (try prog.checkLineMatch(allocator, file_entries.items)) |info| return info;
prog.basic_block = false;
},
LNS.advance_pc => {
const arg = try leb.readULEB128(usize, in);
prog.address += arg * minimum_instruction_length;
},
LNS.advance_line => {
const arg = try leb.readILEB128(i64, in);
prog.line += arg;
},
LNS.set_file => {
const arg = try leb.readULEB128(usize, in);
prog.file = arg;
},
LNS.set_column => {
const arg = try leb.readULEB128(u64, in);
prog.column = arg;
},
LNS.negate_stmt => {
prog.is_stmt = !prog.is_stmt;
},
LNS.set_basic_block => {
prog.basic_block = true;
},
LNS.const_add_pc => {
const inc_addr = minimum_instruction_length * ((255 - opcode_base) / line_range);
prog.address += inc_addr;
},
LNS.fixed_advance_pc => {
const arg = try in.readInt(u16, di.endian);
prog.address += arg;
},
LNS.set_prologue_end => {},
else => {
if (opcode - 1 >= standard_opcode_lengths.len) return badDwarf();
const len_bytes = standard_opcode_lengths[opcode - 1];
try seekable.seekBy(len_bytes);
},
}
}
}
return missingDwarf();
}
fn getString(di: DwarfInfo, offset: u64) ![]const u8 {
return getStringGeneric(di.debug_str, offset);
}
fn getLineString(di: DwarfInfo, offset: u64) ![]const u8 {
return getStringGeneric(di.debug_line_str, offset);
}
};
/// Initialize DWARF info. The caller has the responsibility to initialize most
/// the DwarfInfo fields before calling.
pub fn openDwarfDebugInfo(di: *DwarfInfo, allocator: mem.Allocator) !void {
try di.scanAllFunctions(allocator);
try di.scanAllCompileUnits(allocator);
}
/// This function is to make it handy to comment out the return and make it
/// into a crash when working on this file.
fn badDwarf() error{InvalidDebugInfo} {
//std.os.abort(); // can be handy to uncomment when working on this file
return error.InvalidDebugInfo;
}
fn missingDwarf() error{MissingDebugInfo} {
//std.os.abort(); // can be handy to uncomment when working on this file
return error.MissingDebugInfo;
}
fn getStringGeneric(opt_str: ?[]const u8, offset: u64) ![:0]const u8 {
const str = opt_str orelse return badDwarf();
if (offset > str.len) return badDwarf();
const casted_offset = math.cast(usize, offset) orelse return badDwarf();
// Valid strings always have a terminating zero byte
const last = mem.indexOfScalarPos(u8, str, casted_offset, 0) orelse return badDwarf();
return str[casted_offset..last :0];
}
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