    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];
    }