master
   1const std = @import("std");
   2const assert = std.debug.assert;
   3const elf = std.elf;
   4const fs = std.fs;
   5const macho = std.macho;
   6const math = std.math;
   7const mem = std.mem;
   8const testing = std.testing;
   9const Writer = std.Io.Writer;
  10
  11const CheckObject = @This();
  12
  13const Allocator = mem.Allocator;
  14const Step = std.Build.Step;
  15
  16pub const base_id: Step.Id = .check_object;
  17
  18step: Step,
  19source: std.Build.LazyPath,
  20max_bytes: usize = 20 * 1024 * 1024,
  21checks: std.array_list.Managed(Check),
  22obj_format: std.Target.ObjectFormat,
  23
  24pub fn create(
  25    owner: *std.Build,
  26    source: std.Build.LazyPath,
  27    obj_format: std.Target.ObjectFormat,
  28) *CheckObject {
  29    const gpa = owner.allocator;
  30    const check_object = gpa.create(CheckObject) catch @panic("OOM");
  31    check_object.* = .{
  32        .step = .init(.{
  33            .id = base_id,
  34            .name = "CheckObject",
  35            .owner = owner,
  36            .makeFn = make,
  37        }),
  38        .source = source.dupe(owner),
  39        .checks = std.array_list.Managed(Check).init(gpa),
  40        .obj_format = obj_format,
  41    };
  42    check_object.source.addStepDependencies(&check_object.step);
  43    return check_object;
  44}
  45
  46const SearchPhrase = struct {
  47    string: []const u8,
  48    lazy_path: ?std.Build.LazyPath = null,
  49
  50    fn resolve(phrase: SearchPhrase, b: *std.Build, step: *Step) []const u8 {
  51        const lazy_path = phrase.lazy_path orelse return phrase.string;
  52        return b.fmt("{s} {s}", .{ phrase.string, lazy_path.getPath2(b, step) });
  53    }
  54};
  55
  56/// There five types of actions currently supported:
  57/// .exact - will do an exact match against the haystack
  58/// .contains - will check for existence within the haystack
  59/// .not_present - will check for non-existence within the haystack
  60/// .extract - will do an exact match and extract into a variable enclosed within `{name}` braces
  61/// .compute_cmp - will perform an operation on the extracted global variables
  62/// using the MatchAction. It currently only supports an addition. The operation is required
  63/// to be specified in Reverse Polish Notation to ease in operator-precedence parsing (well,
  64/// to avoid any parsing really).
  65/// For example, if the two extracted values were saved as `vmaddr` and `entryoff` respectively
  66/// they could then be added with this simple program `vmaddr entryoff +`.
  67const Action = struct {
  68    tag: enum { exact, contains, not_present, extract, compute_cmp },
  69    phrase: SearchPhrase,
  70    expected: ?ComputeCompareExpected = null,
  71
  72    /// Returns true if the `phrase` is an exact match with the haystack and variable was successfully extracted.
  73    fn extract(
  74        act: Action,
  75        b: *std.Build,
  76        step: *Step,
  77        haystack: []const u8,
  78        global_vars: anytype,
  79    ) !bool {
  80        assert(act.tag == .extract);
  81        const hay = mem.trim(u8, haystack, " ");
  82        const phrase = mem.trim(u8, act.phrase.resolve(b, step), " ");
  83
  84        var candidate_vars: std.array_list.Managed(struct { name: []const u8, value: u64 }) = .init(b.allocator);
  85        var hay_it = mem.tokenizeScalar(u8, hay, ' ');
  86        var needle_it = mem.tokenizeScalar(u8, phrase, ' ');
  87
  88        while (needle_it.next()) |needle_tok| {
  89            const hay_tok = hay_it.next() orelse break;
  90            if (mem.startsWith(u8, needle_tok, "{")) {
  91                const closing_brace = mem.indexOf(u8, needle_tok, "}") orelse return error.MissingClosingBrace;
  92                if (closing_brace != needle_tok.len - 1) return error.ClosingBraceNotLast;
  93
  94                const name = needle_tok[1..closing_brace];
  95                if (name.len == 0) return error.MissingBraceValue;
  96                const value = std.fmt.parseInt(u64, hay_tok, 16) catch return false;
  97                try candidate_vars.append(.{
  98                    .name = name,
  99                    .value = value,
 100                });
 101            } else {
 102                if (!mem.eql(u8, hay_tok, needle_tok)) return false;
 103            }
 104        }
 105
 106        if (candidate_vars.items.len == 0) return false;
 107
 108        for (candidate_vars.items) |cv| try global_vars.putNoClobber(cv.name, cv.value);
 109
 110        return true;
 111    }
 112
 113    /// Returns true if the `phrase` is an exact match with the haystack.
 114    fn exact(
 115        act: Action,
 116        b: *std.Build,
 117        step: *Step,
 118        haystack: []const u8,
 119    ) bool {
 120        assert(act.tag == .exact);
 121        const hay = mem.trim(u8, haystack, " ");
 122        const phrase = mem.trim(u8, act.phrase.resolve(b, step), " ");
 123        return mem.eql(u8, hay, phrase);
 124    }
 125
 126    /// Returns true if the `phrase` exists within the haystack.
 127    fn contains(
 128        act: Action,
 129        b: *std.Build,
 130        step: *Step,
 131        haystack: []const u8,
 132    ) bool {
 133        assert(act.tag == .contains);
 134        const hay = mem.trim(u8, haystack, " ");
 135        const phrase = mem.trim(u8, act.phrase.resolve(b, step), " ");
 136        return mem.indexOf(u8, hay, phrase) != null;
 137    }
 138
 139    /// Returns true if the `phrase` does not exist within the haystack.
 140    fn notPresent(
 141        act: Action,
 142        b: *std.Build,
 143        step: *Step,
 144        haystack: []const u8,
 145    ) bool {
 146        assert(act.tag == .not_present);
 147        return !contains(.{
 148            .tag = .contains,
 149            .phrase = act.phrase,
 150            .expected = act.expected,
 151        }, b, step, haystack);
 152    }
 153
 154    /// Will return true if the `phrase` is correctly parsed into an RPN program and
 155    /// its reduced, computed value compares using `op` with the expected value, either
 156    /// a literal or another extracted variable.
 157    fn computeCmp(act: Action, b: *std.Build, step: *Step, global_vars: anytype) !bool {
 158        const gpa = step.owner.allocator;
 159        const phrase = act.phrase.resolve(b, step);
 160        var op_stack = std.array_list.Managed(enum { add, sub, mod, mul }).init(gpa);
 161        var values = std.array_list.Managed(u64).init(gpa);
 162
 163        var it = mem.tokenizeScalar(u8, phrase, ' ');
 164        while (it.next()) |next| {
 165            if (mem.eql(u8, next, "+")) {
 166                try op_stack.append(.add);
 167            } else if (mem.eql(u8, next, "-")) {
 168                try op_stack.append(.sub);
 169            } else if (mem.eql(u8, next, "%")) {
 170                try op_stack.append(.mod);
 171            } else if (mem.eql(u8, next, "*")) {
 172                try op_stack.append(.mul);
 173            } else {
 174                const val = std.fmt.parseInt(u64, next, 0) catch blk: {
 175                    break :blk global_vars.get(next) orelse {
 176                        try step.addError(
 177                            \\
 178                            \\========= variable was not extracted: ===========
 179                            \\{s}
 180                            \\=================================================
 181                        , .{next});
 182                        return error.UnknownVariable;
 183                    };
 184                };
 185                try values.append(val);
 186            }
 187        }
 188
 189        var op_i: usize = 1;
 190        var reduced: u64 = values.items[0];
 191        for (op_stack.items) |op| {
 192            const other = values.items[op_i];
 193            switch (op) {
 194                .add => {
 195                    reduced += other;
 196                },
 197                .sub => {
 198                    reduced -= other;
 199                },
 200                .mod => {
 201                    reduced %= other;
 202                },
 203                .mul => {
 204                    reduced *= other;
 205                },
 206            }
 207            op_i += 1;
 208        }
 209
 210        const exp_value = switch (act.expected.?.value) {
 211            .variable => |name| global_vars.get(name) orelse {
 212                try step.addError(
 213                    \\
 214                    \\========= variable was not extracted: ===========
 215                    \\{s}
 216                    \\=================================================
 217                , .{name});
 218                return error.UnknownVariable;
 219            },
 220            .literal => |x| x,
 221        };
 222        return math.compare(reduced, act.expected.?.op, exp_value);
 223    }
 224};
 225
 226const ComputeCompareExpected = struct {
 227    op: math.CompareOperator,
 228    value: union(enum) {
 229        variable: []const u8,
 230        literal: u64,
 231    },
 232
 233    pub fn format(value: ComputeCompareExpected, w: *Writer) Writer.Error!void {
 234        try w.print("{t} ", .{value.op});
 235        switch (value.value) {
 236            .variable => |name| try w.writeAll(name),
 237            .literal => |x| try w.print("{x}", .{x}),
 238        }
 239    }
 240};
 241
 242const Check = struct {
 243    kind: Kind,
 244    payload: Payload,
 245    data: std.array_list.Managed(u8),
 246    actions: std.array_list.Managed(Action),
 247
 248    fn create(allocator: Allocator, kind: Kind) Check {
 249        return .{
 250            .kind = kind,
 251            .payload = .{ .none = {} },
 252            .data = std.array_list.Managed(u8).init(allocator),
 253            .actions = std.array_list.Managed(Action).init(allocator),
 254        };
 255    }
 256
 257    fn dumpSection(allocator: Allocator, name: [:0]const u8) Check {
 258        var check = Check.create(allocator, .dump_section);
 259        const off: u32 = @intCast(check.data.items.len);
 260        check.data.print("{s}\x00", .{name}) catch @panic("OOM");
 261        check.payload = .{ .dump_section = off };
 262        return check;
 263    }
 264
 265    fn extract(check: *Check, phrase: SearchPhrase) void {
 266        check.actions.append(.{
 267            .tag = .extract,
 268            .phrase = phrase,
 269        }) catch @panic("OOM");
 270    }
 271
 272    fn exact(check: *Check, phrase: SearchPhrase) void {
 273        check.actions.append(.{
 274            .tag = .exact,
 275            .phrase = phrase,
 276        }) catch @panic("OOM");
 277    }
 278
 279    fn contains(check: *Check, phrase: SearchPhrase) void {
 280        check.actions.append(.{
 281            .tag = .contains,
 282            .phrase = phrase,
 283        }) catch @panic("OOM");
 284    }
 285
 286    fn notPresent(check: *Check, phrase: SearchPhrase) void {
 287        check.actions.append(.{
 288            .tag = .not_present,
 289            .phrase = phrase,
 290        }) catch @panic("OOM");
 291    }
 292
 293    fn computeCmp(check: *Check, phrase: SearchPhrase, expected: ComputeCompareExpected) void {
 294        check.actions.append(.{
 295            .tag = .compute_cmp,
 296            .phrase = phrase,
 297            .expected = expected,
 298        }) catch @panic("OOM");
 299    }
 300
 301    const Kind = enum {
 302        headers,
 303        symtab,
 304        indirect_symtab,
 305        dynamic_symtab,
 306        archive_symtab,
 307        dynamic_section,
 308        dyld_rebase,
 309        dyld_bind,
 310        dyld_weak_bind,
 311        dyld_lazy_bind,
 312        exports,
 313        compute_compare,
 314        dump_section,
 315    };
 316
 317    const Payload = union {
 318        none: void,
 319        /// Null-delimited string in the 'data' buffer.
 320        dump_section: u32,
 321    };
 322};
 323
 324/// Creates a new empty sequence of actions.
 325fn checkStart(check_object: *CheckObject, kind: Check.Kind) void {
 326    const check = Check.create(check_object.step.owner.allocator, kind);
 327    check_object.checks.append(check) catch @panic("OOM");
 328}
 329
 330/// Adds an exact match phrase to the latest created Check.
 331pub fn checkExact(check_object: *CheckObject, phrase: []const u8) void {
 332    check_object.checkExactInner(phrase, null);
 333}
 334
 335/// Like `checkExact()` but takes an additional argument `LazyPath` which will be
 336/// resolved to a full search query in `make()`.
 337pub fn checkExactPath(check_object: *CheckObject, phrase: []const u8, lazy_path: std.Build.LazyPath) void {
 338    check_object.checkExactInner(phrase, lazy_path);
 339}
 340
 341fn checkExactInner(check_object: *CheckObject, phrase: []const u8, lazy_path: ?std.Build.LazyPath) void {
 342    assert(check_object.checks.items.len > 0);
 343    const last = &check_object.checks.items[check_object.checks.items.len - 1];
 344    last.exact(.{ .string = check_object.step.owner.dupe(phrase), .lazy_path = lazy_path });
 345}
 346
 347/// Adds a fuzzy match phrase to the latest created Check.
 348pub fn checkContains(check_object: *CheckObject, phrase: []const u8) void {
 349    check_object.checkContainsInner(phrase, null);
 350}
 351
 352/// Like `checkContains()` but takes an additional argument `lazy_path` which will be
 353/// resolved to a full search query in `make()`.
 354pub fn checkContainsPath(
 355    check_object: *CheckObject,
 356    phrase: []const u8,
 357    lazy_path: std.Build.LazyPath,
 358) void {
 359    check_object.checkContainsInner(phrase, lazy_path);
 360}
 361
 362fn checkContainsInner(check_object: *CheckObject, phrase: []const u8, lazy_path: ?std.Build.LazyPath) void {
 363    assert(check_object.checks.items.len > 0);
 364    const last = &check_object.checks.items[check_object.checks.items.len - 1];
 365    last.contains(.{ .string = check_object.step.owner.dupe(phrase), .lazy_path = lazy_path });
 366}
 367
 368/// Adds an exact match phrase with variable extractor to the latest created Check.
 369pub fn checkExtract(check_object: *CheckObject, phrase: []const u8) void {
 370    check_object.checkExtractInner(phrase, null);
 371}
 372
 373/// Like `checkExtract()` but takes an additional argument `LazyPath` which will be
 374/// resolved to a full search query in `make()`.
 375pub fn checkExtractLazyPath(check_object: *CheckObject, phrase: []const u8, lazy_path: std.Build.LazyPath) void {
 376    check_object.checkExtractInner(phrase, lazy_path);
 377}
 378
 379fn checkExtractInner(check_object: *CheckObject, phrase: []const u8, lazy_path: ?std.Build.LazyPath) void {
 380    assert(check_object.checks.items.len > 0);
 381    const last = &check_object.checks.items[check_object.checks.items.len - 1];
 382    last.extract(.{ .string = check_object.step.owner.dupe(phrase), .lazy_path = lazy_path });
 383}
 384
 385/// Adds another searched phrase to the latest created Check
 386/// however ensures there is no matching phrase in the output.
 387pub fn checkNotPresent(check_object: *CheckObject, phrase: []const u8) void {
 388    check_object.checkNotPresentInner(phrase, null);
 389}
 390
 391/// Like `checkExtract()` but takes an additional argument `LazyPath` which will be
 392/// resolved to a full search query in `make()`.
 393pub fn checkNotPresentLazyPath(check_object: *CheckObject, phrase: []const u8, lazy_path: std.Build.LazyPath) void {
 394    check_object.checkNotPresentInner(phrase, lazy_path);
 395}
 396
 397fn checkNotPresentInner(check_object: *CheckObject, phrase: []const u8, lazy_path: ?std.Build.LazyPath) void {
 398    assert(check_object.checks.items.len > 0);
 399    const last = &check_object.checks.items[check_object.checks.items.len - 1];
 400    last.notPresent(.{ .string = check_object.step.owner.dupe(phrase), .lazy_path = lazy_path });
 401}
 402
 403/// Creates a new check checking in the file headers (section, program headers, etc.).
 404pub fn checkInHeaders(check_object: *CheckObject) void {
 405    check_object.checkStart(.headers);
 406}
 407
 408/// Creates a new check checking specifically symbol table parsed and dumped from the object
 409/// file.
 410pub fn checkInSymtab(check_object: *CheckObject) void {
 411    const label = switch (check_object.obj_format) {
 412        .macho => MachODumper.symtab_label,
 413        .elf => ElfDumper.symtab_label,
 414        .wasm => WasmDumper.symtab_label,
 415        .coff => @panic("TODO symtab for coff"),
 416        else => @panic("TODO other file formats"),
 417    };
 418    check_object.checkStart(.symtab);
 419    check_object.checkExact(label);
 420}
 421
 422/// Creates a new check checking specifically dyld rebase opcodes contents parsed and dumped
 423/// from the object file.
 424/// This check is target-dependent and applicable to MachO only.
 425pub fn checkInDyldRebase(check_object: *CheckObject) void {
 426    const label = switch (check_object.obj_format) {
 427        .macho => MachODumper.dyld_rebase_label,
 428        else => @panic("Unsupported target platform"),
 429    };
 430    check_object.checkStart(.dyld_rebase);
 431    check_object.checkExact(label);
 432}
 433
 434/// Creates a new check checking specifically dyld bind opcodes contents parsed and dumped
 435/// from the object file.
 436/// This check is target-dependent and applicable to MachO only.
 437pub fn checkInDyldBind(check_object: *CheckObject) void {
 438    const label = switch (check_object.obj_format) {
 439        .macho => MachODumper.dyld_bind_label,
 440        else => @panic("Unsupported target platform"),
 441    };
 442    check_object.checkStart(.dyld_bind);
 443    check_object.checkExact(label);
 444}
 445
 446/// Creates a new check checking specifically dyld weak bind opcodes contents parsed and dumped
 447/// from the object file.
 448/// This check is target-dependent and applicable to MachO only.
 449pub fn checkInDyldWeakBind(check_object: *CheckObject) void {
 450    const label = switch (check_object.obj_format) {
 451        .macho => MachODumper.dyld_weak_bind_label,
 452        else => @panic("Unsupported target platform"),
 453    };
 454    check_object.checkStart(.dyld_weak_bind);
 455    check_object.checkExact(label);
 456}
 457
 458/// Creates a new check checking specifically dyld lazy bind opcodes contents parsed and dumped
 459/// from the object file.
 460/// This check is target-dependent and applicable to MachO only.
 461pub fn checkInDyldLazyBind(check_object: *CheckObject) void {
 462    const label = switch (check_object.obj_format) {
 463        .macho => MachODumper.dyld_lazy_bind_label,
 464        else => @panic("Unsupported target platform"),
 465    };
 466    check_object.checkStart(.dyld_lazy_bind);
 467    check_object.checkExact(label);
 468}
 469
 470/// Creates a new check checking specifically exports info contents parsed and dumped
 471/// from the object file.
 472/// This check is target-dependent and applicable to MachO only.
 473pub fn checkInExports(check_object: *CheckObject) void {
 474    const label = switch (check_object.obj_format) {
 475        .macho => MachODumper.exports_label,
 476        else => @panic("Unsupported target platform"),
 477    };
 478    check_object.checkStart(.exports);
 479    check_object.checkExact(label);
 480}
 481
 482/// Creates a new check checking specifically indirect symbol table parsed and dumped
 483/// from the object file.
 484/// This check is target-dependent and applicable to MachO only.
 485pub fn checkInIndirectSymtab(check_object: *CheckObject) void {
 486    const label = switch (check_object.obj_format) {
 487        .macho => MachODumper.indirect_symtab_label,
 488        else => @panic("Unsupported target platform"),
 489    };
 490    check_object.checkStart(.indirect_symtab);
 491    check_object.checkExact(label);
 492}
 493
 494/// Creates a new check checking specifically dynamic symbol table parsed and dumped from the object
 495/// file.
 496/// This check is target-dependent and applicable to ELF only.
 497pub fn checkInDynamicSymtab(check_object: *CheckObject) void {
 498    const label = switch (check_object.obj_format) {
 499        .elf => ElfDumper.dynamic_symtab_label,
 500        else => @panic("Unsupported target platform"),
 501    };
 502    check_object.checkStart(.dynamic_symtab);
 503    check_object.checkExact(label);
 504}
 505
 506/// Creates a new check checking specifically dynamic section parsed and dumped from the object
 507/// file.
 508/// This check is target-dependent and applicable to ELF only.
 509pub fn checkInDynamicSection(check_object: *CheckObject) void {
 510    const label = switch (check_object.obj_format) {
 511        .elf => ElfDumper.dynamic_section_label,
 512        else => @panic("Unsupported target platform"),
 513    };
 514    check_object.checkStart(.dynamic_section);
 515    check_object.checkExact(label);
 516}
 517
 518/// Creates a new check checking specifically symbol table parsed and dumped from the archive
 519/// file.
 520pub fn checkInArchiveSymtab(check_object: *CheckObject) void {
 521    const label = switch (check_object.obj_format) {
 522        .elf => ElfDumper.archive_symtab_label,
 523        else => @panic("TODO other file formats"),
 524    };
 525    check_object.checkStart(.archive_symtab);
 526    check_object.checkExact(label);
 527}
 528
 529pub fn dumpSection(check_object: *CheckObject, name: [:0]const u8) void {
 530    const check = Check.dumpSection(check_object.step.owner.allocator, name);
 531    check_object.checks.append(check) catch @panic("OOM");
 532}
 533
 534/// Creates a new standalone, singular check which allows running simple binary operations
 535/// on the extracted variables. It will then compare the reduced program with the value of
 536/// the expected variable.
 537pub fn checkComputeCompare(
 538    check_object: *CheckObject,
 539    program: []const u8,
 540    expected: ComputeCompareExpected,
 541) void {
 542    var check = Check.create(check_object.step.owner.allocator, .compute_compare);
 543    check.computeCmp(.{ .string = check_object.step.owner.dupe(program) }, expected);
 544    check_object.checks.append(check) catch @panic("OOM");
 545}
 546
 547fn make(step: *Step, make_options: Step.MakeOptions) !void {
 548    _ = make_options;
 549    const b = step.owner;
 550    const gpa = b.allocator;
 551    const check_object: *CheckObject = @fieldParentPtr("step", step);
 552    try step.singleUnchangingWatchInput(check_object.source);
 553
 554    const src_path = check_object.source.getPath3(b, step);
 555    const contents = src_path.root_dir.handle.readFileAllocOptions(
 556        src_path.sub_path,
 557        gpa,
 558        .limited(check_object.max_bytes),
 559        .of(u64),
 560        null,
 561    ) catch |err| return step.fail("unable to read '{f}': {t}", .{
 562        std.fmt.alt(src_path, .formatEscapeChar), err,
 563    });
 564
 565    var vars: std.StringHashMap(u64) = .init(gpa);
 566    for (check_object.checks.items) |chk| {
 567        if (chk.kind == .compute_compare) {
 568            assert(chk.actions.items.len == 1);
 569            const act = chk.actions.items[0];
 570            assert(act.tag == .compute_cmp);
 571            const res = act.computeCmp(b, step, vars) catch |err| switch (err) {
 572                error.UnknownVariable => return step.fail("Unknown variable", .{}),
 573                else => |e| return e,
 574            };
 575            if (!res) {
 576                return step.fail(
 577                    \\
 578                    \\========= comparison failed for action: ===========
 579                    \\{s} {f}
 580                    \\===================================================
 581                , .{ act.phrase.resolve(b, step), act.expected.? });
 582            }
 583            continue;
 584        }
 585
 586        const output = switch (check_object.obj_format) {
 587            .macho => try MachODumper.parseAndDump(step, chk, contents),
 588            .elf => try ElfDumper.parseAndDump(step, chk, contents),
 589            .coff => return step.fail("TODO coff parser", .{}),
 590            .wasm => try WasmDumper.parseAndDump(step, chk, contents),
 591            else => unreachable,
 592        };
 593
 594        // Depending on whether we requested dumping section verbatim or not,
 595        // we either format message string with escaped codes, or not to aid debugging
 596        // the failed test.
 597        const fmtMessageString = struct {
 598            fn fmtMessageString(kind: Check.Kind, msg: []const u8) std.fmt.Alt(Ctx, formatMessageString) {
 599                return .{ .data = .{
 600                    .kind = kind,
 601                    .msg = msg,
 602                } };
 603            }
 604
 605            const Ctx = struct {
 606                kind: Check.Kind,
 607                msg: []const u8,
 608            };
 609
 610            fn formatMessageString(ctx: Ctx, w: *Writer) !void {
 611                switch (ctx.kind) {
 612                    .dump_section => try w.print("{f}", .{std.ascii.hexEscape(ctx.msg, .lower)}),
 613                    else => try w.writeAll(ctx.msg),
 614                }
 615            }
 616        }.fmtMessageString;
 617
 618        var it = mem.tokenizeAny(u8, output, "\r\n");
 619        for (chk.actions.items) |act| {
 620            switch (act.tag) {
 621                .exact => {
 622                    while (it.next()) |line| {
 623                        if (act.exact(b, step, line)) break;
 624                    } else {
 625                        return step.fail(
 626                            \\
 627                            \\========= expected to find: ==========================
 628                            \\{f}
 629                            \\========= but parsed file does not contain it: =======
 630                            \\{f}
 631                            \\========= file path: =================================
 632                            \\{f}
 633                        , .{
 634                            fmtMessageString(chk.kind, act.phrase.resolve(b, step)),
 635                            fmtMessageString(chk.kind, output),
 636                            src_path,
 637                        });
 638                    }
 639                },
 640
 641                .contains => {
 642                    while (it.next()) |line| {
 643                        if (act.contains(b, step, line)) break;
 644                    } else {
 645                        return step.fail(
 646                            \\
 647                            \\========= expected to find: ==========================
 648                            \\*{f}*
 649                            \\========= but parsed file does not contain it: =======
 650                            \\{f}
 651                            \\========= file path: =================================
 652                            \\{f}
 653                        , .{
 654                            fmtMessageString(chk.kind, act.phrase.resolve(b, step)),
 655                            fmtMessageString(chk.kind, output),
 656                            src_path,
 657                        });
 658                    }
 659                },
 660
 661                .not_present => {
 662                    while (it.next()) |line| {
 663                        if (act.notPresent(b, step, line)) continue;
 664                        return step.fail(
 665                            \\
 666                            \\========= expected not to find: ===================
 667                            \\{f}
 668                            \\========= but parsed file does contain it: ========
 669                            \\{f}
 670                            \\========= file path: ==============================
 671                            \\{f}
 672                        , .{
 673                            fmtMessageString(chk.kind, act.phrase.resolve(b, step)),
 674                            fmtMessageString(chk.kind, output),
 675                            src_path,
 676                        });
 677                    }
 678                },
 679
 680                .extract => {
 681                    while (it.next()) |line| {
 682                        if (try act.extract(b, step, line, &vars)) break;
 683                    } else {
 684                        return step.fail(
 685                            \\
 686                            \\========= expected to find and extract: ==============
 687                            \\{f}
 688                            \\========= but parsed file does not contain it: =======
 689                            \\{f}
 690                            \\========= file path: ==============================
 691                            \\{f}
 692                        , .{
 693                            fmtMessageString(chk.kind, act.phrase.resolve(b, step)),
 694                            fmtMessageString(chk.kind, output),
 695                            src_path,
 696                        });
 697                    }
 698                },
 699
 700                .compute_cmp => unreachable,
 701            }
 702        }
 703    }
 704}
 705
 706const MachODumper = struct {
 707    const dyld_rebase_label = "dyld rebase data";
 708    const dyld_bind_label = "dyld bind data";
 709    const dyld_weak_bind_label = "dyld weak bind data";
 710    const dyld_lazy_bind_label = "dyld lazy bind data";
 711    const exports_label = "exports data";
 712    const symtab_label = "symbol table";
 713    const indirect_symtab_label = "indirect symbol table";
 714
 715    fn parseAndDump(step: *Step, check: Check, bytes: []const u8) ![]const u8 {
 716        // TODO: handle archives and fat files
 717        return parseAndDumpObject(step, check, bytes);
 718    }
 719
 720    const ObjectContext = struct {
 721        gpa: Allocator,
 722        data: []const u8,
 723        header: macho.mach_header_64,
 724        segments: std.ArrayList(macho.segment_command_64) = .empty,
 725        sections: std.ArrayList(macho.section_64) = .empty,
 726        symtab: std.ArrayList(macho.nlist_64) = .empty,
 727        strtab: std.ArrayList(u8) = .empty,
 728        indsymtab: std.ArrayList(u32) = .empty,
 729        imports: std.ArrayList([]const u8) = .empty,
 730
 731        fn parse(ctx: *ObjectContext) !void {
 732            var it = try ctx.getLoadCommandIterator();
 733            var i: usize = 0;
 734            while (try it.next()) |cmd| {
 735                switch (cmd.hdr.cmd) {
 736                    .SEGMENT_64 => {
 737                        const seg = cmd.cast(macho.segment_command_64).?;
 738                        try ctx.segments.append(ctx.gpa, seg);
 739                        try ctx.sections.ensureUnusedCapacity(ctx.gpa, seg.nsects);
 740                        for (cmd.getSections()) |sect| {
 741                            ctx.sections.appendAssumeCapacity(sect);
 742                        }
 743                    },
 744                    .SYMTAB => {
 745                        const lc = cmd.cast(macho.symtab_command).?;
 746                        const symtab = @as([*]align(1) const macho.nlist_64, @ptrCast(ctx.data.ptr + lc.symoff))[0..lc.nsyms];
 747                        const strtab = ctx.data[lc.stroff..][0..lc.strsize];
 748                        try ctx.symtab.appendUnalignedSlice(ctx.gpa, symtab);
 749                        try ctx.strtab.appendSlice(ctx.gpa, strtab);
 750                    },
 751                    .DYSYMTAB => {
 752                        const lc = cmd.cast(macho.dysymtab_command).?;
 753                        const indexes = @as([*]align(1) const u32, @ptrCast(ctx.data.ptr + lc.indirectsymoff))[0..lc.nindirectsyms];
 754                        try ctx.indsymtab.appendUnalignedSlice(ctx.gpa, indexes);
 755                    },
 756                    .LOAD_DYLIB,
 757                    .LOAD_WEAK_DYLIB,
 758                    .REEXPORT_DYLIB,
 759                    => {
 760                        try ctx.imports.append(ctx.gpa, cmd.getDylibPathName());
 761                    },
 762                    else => {},
 763                }
 764
 765                i += 1;
 766            }
 767        }
 768
 769        fn getString(ctx: ObjectContext, off: u32) [:0]const u8 {
 770            assert(off < ctx.strtab.items.len);
 771            return mem.sliceTo(@as([*:0]const u8, @ptrCast(ctx.strtab.items.ptr + off)), 0);
 772        }
 773
 774        fn getLoadCommandIterator(ctx: ObjectContext) !macho.LoadCommandIterator {
 775            return .init(&ctx.header, ctx.data[@sizeOf(macho.mach_header_64)..]);
 776        }
 777
 778        fn getLoadCommand(ctx: ObjectContext, cmd: macho.LC) !?macho.LoadCommandIterator.LoadCommand {
 779            var it = try ctx.getLoadCommandIterator();
 780            while (try it.next()) |lc| if (lc.hdr.cmd == cmd) {
 781                return lc;
 782            };
 783            return null;
 784        }
 785
 786        fn getSegmentByName(ctx: ObjectContext, name: []const u8) ?macho.segment_command_64 {
 787            for (ctx.segments.items) |seg| {
 788                if (mem.eql(u8, seg.segName(), name)) return seg;
 789            }
 790            return null;
 791        }
 792
 793        fn getSectionByName(ctx: ObjectContext, segname: []const u8, sectname: []const u8) ?macho.section_64 {
 794            for (ctx.sections.items) |sect| {
 795                if (mem.eql(u8, sect.segName(), segname) and mem.eql(u8, sect.sectName(), sectname)) return sect;
 796            }
 797            return null;
 798        }
 799
 800        fn dumpHeader(hdr: macho.mach_header_64, writer: anytype) !void {
 801            const cputype = switch (hdr.cputype) {
 802                macho.CPU_TYPE_ARM64 => "ARM64",
 803                macho.CPU_TYPE_X86_64 => "X86_64",
 804                else => "Unknown",
 805            };
 806            const filetype = switch (hdr.filetype) {
 807                macho.MH_OBJECT => "MH_OBJECT",
 808                macho.MH_EXECUTE => "MH_EXECUTE",
 809                macho.MH_FVMLIB => "MH_FVMLIB",
 810                macho.MH_CORE => "MH_CORE",
 811                macho.MH_PRELOAD => "MH_PRELOAD",
 812                macho.MH_DYLIB => "MH_DYLIB",
 813                macho.MH_DYLINKER => "MH_DYLINKER",
 814                macho.MH_BUNDLE => "MH_BUNDLE",
 815                macho.MH_DYLIB_STUB => "MH_DYLIB_STUB",
 816                macho.MH_DSYM => "MH_DSYM",
 817                macho.MH_KEXT_BUNDLE => "MH_KEXT_BUNDLE",
 818                else => "Unknown",
 819            };
 820
 821            try writer.print(
 822                \\header
 823                \\cputype {s}
 824                \\filetype {s}
 825                \\ncmds {d}
 826                \\sizeofcmds {x}
 827                \\flags
 828            , .{
 829                cputype,
 830                filetype,
 831                hdr.ncmds,
 832                hdr.sizeofcmds,
 833            });
 834
 835            if (hdr.flags > 0) {
 836                if (hdr.flags & macho.MH_NOUNDEFS != 0) try writer.writeAll(" NOUNDEFS");
 837                if (hdr.flags & macho.MH_INCRLINK != 0) try writer.writeAll(" INCRLINK");
 838                if (hdr.flags & macho.MH_DYLDLINK != 0) try writer.writeAll(" DYLDLINK");
 839                if (hdr.flags & macho.MH_BINDATLOAD != 0) try writer.writeAll(" BINDATLOAD");
 840                if (hdr.flags & macho.MH_PREBOUND != 0) try writer.writeAll(" PREBOUND");
 841                if (hdr.flags & macho.MH_SPLIT_SEGS != 0) try writer.writeAll(" SPLIT_SEGS");
 842                if (hdr.flags & macho.MH_LAZY_INIT != 0) try writer.writeAll(" LAZY_INIT");
 843                if (hdr.flags & macho.MH_TWOLEVEL != 0) try writer.writeAll(" TWOLEVEL");
 844                if (hdr.flags & macho.MH_FORCE_FLAT != 0) try writer.writeAll(" FORCE_FLAT");
 845                if (hdr.flags & macho.MH_NOMULTIDEFS != 0) try writer.writeAll(" NOMULTIDEFS");
 846                if (hdr.flags & macho.MH_NOFIXPREBINDING != 0) try writer.writeAll(" NOFIXPREBINDING");
 847                if (hdr.flags & macho.MH_PREBINDABLE != 0) try writer.writeAll(" PREBINDABLE");
 848                if (hdr.flags & macho.MH_ALLMODSBOUND != 0) try writer.writeAll(" ALLMODSBOUND");
 849                if (hdr.flags & macho.MH_SUBSECTIONS_VIA_SYMBOLS != 0) try writer.writeAll(" SUBSECTIONS_VIA_SYMBOLS");
 850                if (hdr.flags & macho.MH_CANONICAL != 0) try writer.writeAll(" CANONICAL");
 851                if (hdr.flags & macho.MH_WEAK_DEFINES != 0) try writer.writeAll(" WEAK_DEFINES");
 852                if (hdr.flags & macho.MH_BINDS_TO_WEAK != 0) try writer.writeAll(" BINDS_TO_WEAK");
 853                if (hdr.flags & macho.MH_ALLOW_STACK_EXECUTION != 0) try writer.writeAll(" ALLOW_STACK_EXECUTION");
 854                if (hdr.flags & macho.MH_ROOT_SAFE != 0) try writer.writeAll(" ROOT_SAFE");
 855                if (hdr.flags & macho.MH_SETUID_SAFE != 0) try writer.writeAll(" SETUID_SAFE");
 856                if (hdr.flags & macho.MH_NO_REEXPORTED_DYLIBS != 0) try writer.writeAll(" NO_REEXPORTED_DYLIBS");
 857                if (hdr.flags & macho.MH_PIE != 0) try writer.writeAll(" PIE");
 858                if (hdr.flags & macho.MH_DEAD_STRIPPABLE_DYLIB != 0) try writer.writeAll(" DEAD_STRIPPABLE_DYLIB");
 859                if (hdr.flags & macho.MH_HAS_TLV_DESCRIPTORS != 0) try writer.writeAll(" HAS_TLV_DESCRIPTORS");
 860                if (hdr.flags & macho.MH_NO_HEAP_EXECUTION != 0) try writer.writeAll(" NO_HEAP_EXECUTION");
 861                if (hdr.flags & macho.MH_APP_EXTENSION_SAFE != 0) try writer.writeAll(" APP_EXTENSION_SAFE");
 862                if (hdr.flags & macho.MH_NLIST_OUTOFSYNC_WITH_DYLDINFO != 0) try writer.writeAll(" NLIST_OUTOFSYNC_WITH_DYLDINFO");
 863            }
 864
 865            try writer.writeByte('\n');
 866        }
 867
 868        fn dumpLoadCommand(lc: macho.LoadCommandIterator.LoadCommand, index: usize, writer: anytype) !void {
 869            // print header first
 870            try writer.print(
 871                \\LC {d}
 872                \\cmd {s}
 873                \\cmdsize {d}
 874            , .{ index, @tagName(lc.hdr.cmd), lc.hdr.cmdsize });
 875
 876            switch (lc.hdr.cmd) {
 877                .SEGMENT_64 => {
 878                    const seg = lc.cast(macho.segment_command_64).?;
 879                    try writer.writeByte('\n');
 880                    try writer.print(
 881                        \\segname {s}
 882                        \\vmaddr {x}
 883                        \\vmsize {x}
 884                        \\fileoff {x}
 885                        \\filesz {x}
 886                    , .{
 887                        seg.segName(),
 888                        seg.vmaddr,
 889                        seg.vmsize,
 890                        seg.fileoff,
 891                        seg.filesize,
 892                    });
 893
 894                    for (lc.getSections()) |sect| {
 895                        try writer.writeByte('\n');
 896                        try writer.print(
 897                            \\sectname {s}
 898                            \\addr {x}
 899                            \\size {x}
 900                            \\offset {x}
 901                            \\align {x}
 902                        , .{
 903                            sect.sectName(),
 904                            sect.addr,
 905                            sect.size,
 906                            sect.offset,
 907                            sect.@"align",
 908                        });
 909                    }
 910                },
 911
 912                .ID_DYLIB,
 913                .LOAD_DYLIB,
 914                .LOAD_WEAK_DYLIB,
 915                .REEXPORT_DYLIB,
 916                => {
 917                    const dylib = lc.cast(macho.dylib_command).?;
 918                    try writer.writeByte('\n');
 919                    try writer.print(
 920                        \\name {s}
 921                        \\timestamp {d}
 922                        \\current version {x}
 923                        \\compatibility version {x}
 924                    , .{
 925                        lc.getDylibPathName(),
 926                        dylib.dylib.timestamp,
 927                        dylib.dylib.current_version,
 928                        dylib.dylib.compatibility_version,
 929                    });
 930                },
 931
 932                .MAIN => {
 933                    const main = lc.cast(macho.entry_point_command).?;
 934                    try writer.writeByte('\n');
 935                    try writer.print(
 936                        \\entryoff {x}
 937                        \\stacksize {x}
 938                    , .{ main.entryoff, main.stacksize });
 939                },
 940
 941                .RPATH => {
 942                    try writer.writeByte('\n');
 943                    try writer.print(
 944                        \\path {s}
 945                    , .{
 946                        lc.getRpathPathName(),
 947                    });
 948                },
 949
 950                .UUID => {
 951                    const uuid = lc.cast(macho.uuid_command).?;
 952                    try writer.writeByte('\n');
 953                    try writer.print("uuid {x}", .{&uuid.uuid});
 954                },
 955
 956                .DATA_IN_CODE,
 957                .FUNCTION_STARTS,
 958                .CODE_SIGNATURE,
 959                => {
 960                    const llc = lc.cast(macho.linkedit_data_command).?;
 961                    try writer.writeByte('\n');
 962                    try writer.print(
 963                        \\dataoff {x}
 964                        \\datasize {x}
 965                    , .{ llc.dataoff, llc.datasize });
 966                },
 967
 968                .DYLD_INFO_ONLY => {
 969                    const dlc = lc.cast(macho.dyld_info_command).?;
 970                    try writer.writeByte('\n');
 971                    try writer.print(
 972                        \\rebaseoff {x}
 973                        \\rebasesize {x}
 974                        \\bindoff {x}
 975                        \\bindsize {x}
 976                        \\weakbindoff {x}
 977                        \\weakbindsize {x}
 978                        \\lazybindoff {x}
 979                        \\lazybindsize {x}
 980                        \\exportoff {x}
 981                        \\exportsize {x}
 982                    , .{
 983                        dlc.rebase_off,
 984                        dlc.rebase_size,
 985                        dlc.bind_off,
 986                        dlc.bind_size,
 987                        dlc.weak_bind_off,
 988                        dlc.weak_bind_size,
 989                        dlc.lazy_bind_off,
 990                        dlc.lazy_bind_size,
 991                        dlc.export_off,
 992                        dlc.export_size,
 993                    });
 994                },
 995
 996                .SYMTAB => {
 997                    const slc = lc.cast(macho.symtab_command).?;
 998                    try writer.writeByte('\n');
 999                    try writer.print(
1000                        \\symoff {x}
1001                        \\nsyms {x}
1002                        \\stroff {x}
1003                        \\strsize {x}
1004                    , .{
1005                        slc.symoff,
1006                        slc.nsyms,
1007                        slc.stroff,
1008                        slc.strsize,
1009                    });
1010                },
1011
1012                .DYSYMTAB => {
1013                    const dlc = lc.cast(macho.dysymtab_command).?;
1014                    try writer.writeByte('\n');
1015                    try writer.print(
1016                        \\ilocalsym {x}
1017                        \\nlocalsym {x}
1018                        \\iextdefsym {x}
1019                        \\nextdefsym {x}
1020                        \\iundefsym {x}
1021                        \\nundefsym {x}
1022                        \\indirectsymoff {x}
1023                        \\nindirectsyms {x}
1024                    , .{
1025                        dlc.ilocalsym,
1026                        dlc.nlocalsym,
1027                        dlc.iextdefsym,
1028                        dlc.nextdefsym,
1029                        dlc.iundefsym,
1030                        dlc.nundefsym,
1031                        dlc.indirectsymoff,
1032                        dlc.nindirectsyms,
1033                    });
1034                },
1035
1036                .BUILD_VERSION => {
1037                    const blc = lc.cast(macho.build_version_command).?;
1038                    try writer.writeByte('\n');
1039                    try writer.print(
1040                        \\platform {s}
1041                        \\minos {d}.{d}.{d}
1042                        \\sdk {d}.{d}.{d}
1043                        \\ntools {d}
1044                    , .{
1045                        @tagName(blc.platform),
1046                        blc.minos >> 16,
1047                        @as(u8, @truncate(blc.minos >> 8)),
1048                        @as(u8, @truncate(blc.minos)),
1049                        blc.sdk >> 16,
1050                        @as(u8, @truncate(blc.sdk >> 8)),
1051                        @as(u8, @truncate(blc.sdk)),
1052                        blc.ntools,
1053                    });
1054                    for (lc.getBuildVersionTools()) |tool| {
1055                        try writer.writeByte('\n');
1056                        switch (tool.tool) {
1057                            .CLANG, .SWIFT, .LD, .LLD, .ZIG => try writer.print("tool {s}\n", .{@tagName(tool.tool)}),
1058                            else => |x| try writer.print("tool {d}\n", .{@intFromEnum(x)}),
1059                        }
1060                        try writer.print(
1061                            \\version {d}.{d}.{d}
1062                        , .{
1063                            tool.version >> 16,
1064                            @as(u8, @truncate(tool.version >> 8)),
1065                            @as(u8, @truncate(tool.version)),
1066                        });
1067                    }
1068                },
1069
1070                .VERSION_MIN_MACOSX,
1071                .VERSION_MIN_IPHONEOS,
1072                .VERSION_MIN_WATCHOS,
1073                .VERSION_MIN_TVOS,
1074                => {
1075                    const vlc = lc.cast(macho.version_min_command).?;
1076                    try writer.writeByte('\n');
1077                    try writer.print(
1078                        \\version {d}.{d}.{d}
1079                        \\sdk {d}.{d}.{d}
1080                    , .{
1081                        vlc.version >> 16,
1082                        @as(u8, @truncate(vlc.version >> 8)),
1083                        @as(u8, @truncate(vlc.version)),
1084                        vlc.sdk >> 16,
1085                        @as(u8, @truncate(vlc.sdk >> 8)),
1086                        @as(u8, @truncate(vlc.sdk)),
1087                    });
1088                },
1089
1090                else => {},
1091            }
1092        }
1093
1094        fn dumpSymtab(ctx: ObjectContext, writer: anytype) !void {
1095            try writer.writeAll(symtab_label ++ "\n");
1096
1097            for (ctx.symtab.items) |sym| {
1098                const sym_name = ctx.getString(sym.n_strx);
1099                if (sym.n_type.bits.is_stab != 0) {
1100                    const tt = switch (sym.n_type.stab) {
1101                        _ => "UNKNOWN STAB",
1102                        else => @tagName(sym.n_type.stab),
1103                    };
1104                    try writer.print("{x}", .{sym.n_value});
1105                    if (sym.n_sect > 0) {
1106                        const sect = ctx.sections.items[sym.n_sect - 1];
1107                        try writer.print(" ({s},{s})", .{ sect.segName(), sect.sectName() });
1108                    }
1109                    try writer.print(" {s} (stab) {s}\n", .{ tt, sym_name });
1110                } else if (sym.n_type.bits.type == .sect) {
1111                    const sect = ctx.sections.items[sym.n_sect - 1];
1112                    try writer.print("{x} ({s},{s})", .{
1113                        sym.n_value,
1114                        sect.segName(),
1115                        sect.sectName(),
1116                    });
1117                    if (sym.n_desc.referenced_dynamically) try writer.writeAll(" [referenced dynamically]");
1118                    if (sym.n_desc.weak_def_or_ref_to_weak) try writer.writeAll(" weak");
1119                    if (sym.n_desc.weak_ref) try writer.writeAll(" weakref");
1120                    if (sym.n_type.bits.ext) {
1121                        if (sym.n_type.bits.pext) try writer.writeAll(" private");
1122                        try writer.writeAll(" external");
1123                    } else if (sym.n_type.bits.pext) try writer.writeAll(" (was private external)");
1124                    try writer.print(" {s}\n", .{sym_name});
1125                } else if (sym.tentative()) {
1126                    const alignment = (@as(u16, @bitCast(sym.n_desc)) >> 8) & 0x0F;
1127                    try writer.print("  0x{x:0>16} (common) (alignment 2^{d})", .{ sym.n_value, alignment });
1128                    if (sym.n_type.bits.ext) try writer.writeAll(" external");
1129                    try writer.print(" {s}\n", .{sym_name});
1130                } else if (sym.n_type.bits.type == .undf) {
1131                    const ordinal = @divFloor(@as(i16, @bitCast(sym.n_desc)), macho.N_SYMBOL_RESOLVER);
1132                    const import_name = blk: {
1133                        if (ordinal <= 0) {
1134                            if (ordinal == macho.BIND_SPECIAL_DYLIB_SELF)
1135                                break :blk "self import";
1136                            if (ordinal == macho.BIND_SPECIAL_DYLIB_MAIN_EXECUTABLE)
1137                                break :blk "main executable";
1138                            if (ordinal == macho.BIND_SPECIAL_DYLIB_FLAT_LOOKUP)
1139                                break :blk "flat lookup";
1140                            unreachable;
1141                        }
1142                        const full_path = ctx.imports.items[@as(u16, @bitCast(ordinal)) - 1];
1143                        const basename = fs.path.basename(full_path);
1144                        assert(basename.len > 0);
1145                        const ext = mem.lastIndexOfScalar(u8, basename, '.') orelse basename.len;
1146                        break :blk basename[0..ext];
1147                    };
1148                    try writer.writeAll("(undefined)");
1149                    if (sym.n_desc.weak_ref) try writer.writeAll(" weakref");
1150                    if (sym.n_type.bits.ext) try writer.writeAll(" external");
1151                    try writer.print(" {s} (from {s})\n", .{
1152                        sym_name,
1153                        import_name,
1154                    });
1155                }
1156            }
1157        }
1158
1159        fn dumpIndirectSymtab(ctx: ObjectContext, writer: anytype) !void {
1160            try writer.writeAll(indirect_symtab_label ++ "\n");
1161
1162            var sects_buffer: [3]macho.section_64 = undefined;
1163            const sects = blk: {
1164                var count: usize = 0;
1165                if (ctx.getSectionByName("__TEXT", "__stubs")) |sect| {
1166                    sects_buffer[count] = sect;
1167                    count += 1;
1168                }
1169                if (ctx.getSectionByName("__DATA_CONST", "__got")) |sect| {
1170                    sects_buffer[count] = sect;
1171                    count += 1;
1172                }
1173                if (ctx.getSectionByName("__DATA", "__la_symbol_ptr")) |sect| {
1174                    sects_buffer[count] = sect;
1175                    count += 1;
1176                }
1177                break :blk sects_buffer[0..count];
1178            };
1179
1180            const sortFn = struct {
1181                fn sortFn(c: void, lhs: macho.section_64, rhs: macho.section_64) bool {
1182                    _ = c;
1183                    return lhs.reserved1 < rhs.reserved1;
1184                }
1185            }.sortFn;
1186            mem.sort(macho.section_64, sects, {}, sortFn);
1187
1188            var i: usize = 0;
1189            while (i < sects.len) : (i += 1) {
1190                const sect = sects[i];
1191                const start = sect.reserved1;
1192                const end = if (i + 1 >= sects.len) ctx.indsymtab.items.len else sects[i + 1].reserved1;
1193                const entry_size = blk: {
1194                    if (mem.eql(u8, sect.sectName(), "__stubs")) break :blk sect.reserved2;
1195                    break :blk @sizeOf(u64);
1196                };
1197
1198                try writer.print("{s},{s}\n", .{ sect.segName(), sect.sectName() });
1199                try writer.print("nentries {d}\n", .{end - start});
1200                for (ctx.indsymtab.items[start..end], 0..) |index, j| {
1201                    const sym = ctx.symtab.items[index];
1202                    const addr = sect.addr + entry_size * j;
1203                    try writer.print("0x{x} {d} {s}\n", .{ addr, index, ctx.getString(sym.n_strx) });
1204                }
1205            }
1206        }
1207
1208        fn dumpRebaseInfo(ctx: ObjectContext, data: []const u8, writer: anytype) !void {
1209            var rebases = std.array_list.Managed(u64).init(ctx.gpa);
1210            defer rebases.deinit();
1211            try ctx.parseRebaseInfo(data, &rebases);
1212            mem.sort(u64, rebases.items, {}, std.sort.asc(u64));
1213            for (rebases.items) |addr| {
1214                try writer.print("0x{x}\n", .{addr});
1215            }
1216        }
1217
1218        fn parseRebaseInfo(ctx: ObjectContext, data: []const u8, rebases: *std.array_list.Managed(u64)) !void {
1219            var reader: std.Io.Reader = .fixed(data);
1220
1221            var seg_id: ?u8 = null;
1222            var offset: u64 = 0;
1223            while (true) {
1224                const byte = reader.takeByte() catch break;
1225                const opc = byte & macho.REBASE_OPCODE_MASK;
1226                const imm = byte & macho.REBASE_IMMEDIATE_MASK;
1227                switch (opc) {
1228                    macho.REBASE_OPCODE_DONE => break,
1229                    macho.REBASE_OPCODE_SET_TYPE_IMM => {},
1230                    macho.REBASE_OPCODE_SET_SEGMENT_AND_OFFSET_ULEB => {
1231                        seg_id = imm;
1232                        offset = try reader.takeLeb128(u64);
1233                    },
1234                    macho.REBASE_OPCODE_ADD_ADDR_IMM_SCALED => {
1235                        offset += imm * @sizeOf(u64);
1236                    },
1237                    macho.REBASE_OPCODE_ADD_ADDR_ULEB => {
1238                        const addend = try reader.takeLeb128(u64);
1239                        offset += addend;
1240                    },
1241                    macho.REBASE_OPCODE_DO_REBASE_ADD_ADDR_ULEB => {
1242                        const addend = try reader.takeLeb128(u64);
1243                        const seg = ctx.segments.items[seg_id.?];
1244                        const addr = seg.vmaddr + offset;
1245                        try rebases.append(addr);
1246                        offset += addend + @sizeOf(u64);
1247                    },
1248                    macho.REBASE_OPCODE_DO_REBASE_IMM_TIMES,
1249                    macho.REBASE_OPCODE_DO_REBASE_ULEB_TIMES,
1250                    macho.REBASE_OPCODE_DO_REBASE_ULEB_TIMES_SKIPPING_ULEB,
1251                    => {
1252                        var ntimes: u64 = 1;
1253                        var skip: u64 = 0;
1254                        switch (opc) {
1255                            macho.REBASE_OPCODE_DO_REBASE_IMM_TIMES => {
1256                                ntimes = imm;
1257                            },
1258                            macho.REBASE_OPCODE_DO_REBASE_ULEB_TIMES => {
1259                                ntimes = try reader.takeLeb128(u64);
1260                            },
1261                            macho.REBASE_OPCODE_DO_REBASE_ULEB_TIMES_SKIPPING_ULEB => {
1262                                ntimes = try reader.takeLeb128(u64);
1263                                skip = try reader.takeLeb128(u64);
1264                            },
1265                            else => unreachable,
1266                        }
1267                        const seg = ctx.segments.items[seg_id.?];
1268                        const base_addr = seg.vmaddr;
1269                        var count: usize = 0;
1270                        while (count < ntimes) : (count += 1) {
1271                            const addr = base_addr + offset;
1272                            try rebases.append(addr);
1273                            offset += skip + @sizeOf(u64);
1274                        }
1275                    },
1276                    else => break,
1277                }
1278            }
1279        }
1280
1281        const Binding = struct {
1282            address: u64,
1283            addend: i64,
1284            ordinal: u16,
1285            tag: Tag,
1286            name: []const u8,
1287
1288            fn deinit(binding: *Binding, gpa: Allocator) void {
1289                gpa.free(binding.name);
1290            }
1291
1292            fn lessThan(ctx: void, lhs: Binding, rhs: Binding) bool {
1293                _ = ctx;
1294                return lhs.address < rhs.address;
1295            }
1296
1297            const Tag = enum {
1298                ord,
1299                self,
1300                exe,
1301                flat,
1302            };
1303        };
1304
1305        fn dumpBindInfo(ctx: ObjectContext, data: []const u8, writer: anytype) !void {
1306            var bindings = std.array_list.Managed(Binding).init(ctx.gpa);
1307            defer {
1308                for (bindings.items) |*b| {
1309                    b.deinit(ctx.gpa);
1310                }
1311                bindings.deinit();
1312            }
1313            var data_reader: std.Io.Reader = .fixed(data);
1314            try ctx.parseBindInfo(&data_reader, &bindings);
1315            mem.sort(Binding, bindings.items, {}, Binding.lessThan);
1316            for (bindings.items) |binding| {
1317                try writer.print("0x{x} [addend: {d}]", .{ binding.address, binding.addend });
1318                try writer.writeAll(" (");
1319                switch (binding.tag) {
1320                    .self => try writer.writeAll("self"),
1321                    .exe => try writer.writeAll("main executable"),
1322                    .flat => try writer.writeAll("flat lookup"),
1323                    .ord => try writer.writeAll(std.fs.path.basename(ctx.imports.items[binding.ordinal - 1])),
1324                }
1325                try writer.print(") {s}\n", .{binding.name});
1326            }
1327        }
1328
1329        fn parseBindInfo(ctx: ObjectContext, reader: *std.Io.Reader, bindings: *std.array_list.Managed(Binding)) !void {
1330            var seg_id: ?u8 = null;
1331            var tag: Binding.Tag = .self;
1332            var ordinal: u16 = 0;
1333            var offset: u64 = 0;
1334            var addend: i64 = 0;
1335
1336            var name_buf = std.array_list.Managed(u8).init(ctx.gpa);
1337            defer name_buf.deinit();
1338
1339            while (true) {
1340                const byte = reader.takeByte() catch break;
1341                const opc = byte & macho.BIND_OPCODE_MASK;
1342                const imm = byte & macho.BIND_IMMEDIATE_MASK;
1343                switch (opc) {
1344                    macho.BIND_OPCODE_DONE,
1345                    macho.BIND_OPCODE_SET_TYPE_IMM,
1346                    => {},
1347                    macho.BIND_OPCODE_SET_DYLIB_ORDINAL_IMM => {
1348                        tag = .ord;
1349                        ordinal = imm;
1350                    },
1351                    macho.BIND_OPCODE_SET_DYLIB_SPECIAL_IMM => {
1352                        switch (imm) {
1353                            0 => tag = .self,
1354                            0xf => tag = .exe,
1355                            0xe => tag = .flat,
1356                            else => unreachable,
1357                        }
1358                    },
1359                    macho.BIND_OPCODE_SET_SEGMENT_AND_OFFSET_ULEB => {
1360                        seg_id = imm;
1361                        offset = try reader.takeLeb128(u64);
1362                    },
1363                    macho.BIND_OPCODE_SET_SYMBOL_TRAILING_FLAGS_IMM => {
1364                        name_buf.clearRetainingCapacity();
1365                        try name_buf.appendSlice(try reader.takeDelimiterInclusive(0));
1366                    },
1367                    macho.BIND_OPCODE_SET_ADDEND_SLEB => {
1368                        addend = try reader.takeLeb128(i64);
1369                    },
1370                    macho.BIND_OPCODE_ADD_ADDR_ULEB => {
1371                        const x = try reader.takeLeb128(u64);
1372                        offset = @intCast(@as(i64, @intCast(offset)) + @as(i64, @bitCast(x)));
1373                    },
1374                    macho.BIND_OPCODE_DO_BIND,
1375                    macho.BIND_OPCODE_DO_BIND_ADD_ADDR_ULEB,
1376                    macho.BIND_OPCODE_DO_BIND_ADD_ADDR_IMM_SCALED,
1377                    macho.BIND_OPCODE_DO_BIND_ULEB_TIMES_SKIPPING_ULEB,
1378                    => {
1379                        var add_addr: u64 = 0;
1380                        var count: u64 = 1;
1381                        var skip: u64 = 0;
1382
1383                        switch (opc) {
1384                            macho.BIND_OPCODE_DO_BIND => {},
1385                            macho.BIND_OPCODE_DO_BIND_ADD_ADDR_ULEB => {
1386                                add_addr = try reader.takeLeb128(u64);
1387                            },
1388                            macho.BIND_OPCODE_DO_BIND_ADD_ADDR_IMM_SCALED => {
1389                                add_addr = imm * @sizeOf(u64);
1390                            },
1391                            macho.BIND_OPCODE_DO_BIND_ULEB_TIMES_SKIPPING_ULEB => {
1392                                count = try reader.takeLeb128(u64);
1393                                skip = try reader.takeLeb128(u64);
1394                            },
1395                            else => unreachable,
1396                        }
1397
1398                        const seg = ctx.segments.items[seg_id.?];
1399                        var i: u64 = 0;
1400                        while (i < count) : (i += 1) {
1401                            const addr: u64 = @intCast(@as(i64, @intCast(seg.vmaddr + offset)));
1402                            try bindings.append(.{
1403                                .address = addr,
1404                                .addend = addend,
1405                                .tag = tag,
1406                                .ordinal = ordinal,
1407                                .name = try ctx.gpa.dupe(u8, name_buf.items),
1408                            });
1409                            offset += skip + @sizeOf(u64) + add_addr;
1410                        }
1411                    },
1412                    else => break,
1413                }
1414            }
1415        }
1416
1417        fn dumpExportsTrie(ctx: ObjectContext, data: []const u8, writer: anytype) !void {
1418            const seg = ctx.getSegmentByName("__TEXT") orelse return;
1419
1420            var arena = std.heap.ArenaAllocator.init(ctx.gpa);
1421            defer arena.deinit();
1422
1423            var exports = std.array_list.Managed(Export).init(arena.allocator());
1424            var it: TrieIterator = .{ .stream = .fixed(data) };
1425            try parseTrieNode(arena.allocator(), &it, "", &exports);
1426
1427            mem.sort(Export, exports.items, {}, Export.lessThan);
1428
1429            for (exports.items) |exp| {
1430                switch (exp.tag) {
1431                    .@"export" => {
1432                        const info = exp.data.@"export";
1433                        if (info.kind != .regular or info.weak) {
1434                            try writer.writeByte('[');
1435                        }
1436                        switch (info.kind) {
1437                            .regular => {},
1438                            .absolute => try writer.writeAll("ABS, "),
1439                            .tlv => try writer.writeAll("THREAD_LOCAL, "),
1440                        }
1441                        if (info.weak) try writer.writeAll("WEAK");
1442                        if (info.kind != .regular or info.weak) {
1443                            try writer.writeAll("] ");
1444                        }
1445                        try writer.print("{x} ", .{seg.vmaddr + info.vmoffset});
1446                    },
1447                    else => {},
1448                }
1449
1450                try writer.print("{s}\n", .{exp.name});
1451            }
1452        }
1453
1454        const TrieIterator = struct {
1455            stream: std.Io.Reader,
1456
1457            fn takeLeb128(it: *TrieIterator) !u64 {
1458                return it.stream.takeLeb128(u64);
1459            }
1460
1461            fn readString(it: *TrieIterator) ![:0]const u8 {
1462                return it.stream.takeSentinel(0);
1463            }
1464
1465            fn takeByte(it: *TrieIterator) !u8 {
1466                return it.stream.takeByte();
1467            }
1468        };
1469
1470        const Export = struct {
1471            name: []const u8,
1472            tag: enum { @"export", reexport, stub_resolver },
1473            data: union {
1474                @"export": struct {
1475                    kind: enum { regular, absolute, tlv },
1476                    weak: bool = false,
1477                    vmoffset: u64,
1478                },
1479                reexport: u64,
1480                stub_resolver: struct {
1481                    stub_offset: u64,
1482                    resolver_offset: u64,
1483                },
1484            },
1485
1486            inline fn rankByTag(@"export": Export) u3 {
1487                return switch (@"export".tag) {
1488                    .@"export" => 1,
1489                    .reexport => 2,
1490                    .stub_resolver => 3,
1491                };
1492            }
1493
1494            fn lessThan(ctx: void, lhs: Export, rhs: Export) bool {
1495                _ = ctx;
1496                if (lhs.rankByTag() == rhs.rankByTag()) {
1497                    return switch (lhs.tag) {
1498                        .@"export" => lhs.data.@"export".vmoffset < rhs.data.@"export".vmoffset,
1499                        .reexport => lhs.data.reexport < rhs.data.reexport,
1500                        .stub_resolver => lhs.data.stub_resolver.stub_offset < rhs.data.stub_resolver.stub_offset,
1501                    };
1502                }
1503                return lhs.rankByTag() < rhs.rankByTag();
1504            }
1505        };
1506
1507        fn parseTrieNode(
1508            arena: Allocator,
1509            it: *TrieIterator,
1510            prefix: []const u8,
1511            exports: *std.array_list.Managed(Export),
1512        ) !void {
1513            const size = try it.takeLeb128();
1514            if (size > 0) {
1515                const flags = try it.takeLeb128();
1516                switch (flags) {
1517                    macho.EXPORT_SYMBOL_FLAGS_REEXPORT => {
1518                        const ord = try it.takeLeb128();
1519                        const name = try arena.dupe(u8, try it.readString());
1520                        try exports.append(.{
1521                            .name = if (name.len > 0) name else prefix,
1522                            .tag = .reexport,
1523                            .data = .{ .reexport = ord },
1524                        });
1525                    },
1526                    macho.EXPORT_SYMBOL_FLAGS_STUB_AND_RESOLVER => {
1527                        const stub_offset = try it.takeLeb128();
1528                        const resolver_offset = try it.takeLeb128();
1529                        try exports.append(.{
1530                            .name = prefix,
1531                            .tag = .stub_resolver,
1532                            .data = .{ .stub_resolver = .{
1533                                .stub_offset = stub_offset,
1534                                .resolver_offset = resolver_offset,
1535                            } },
1536                        });
1537                    },
1538                    else => {
1539                        const vmoff = try it.takeLeb128();
1540                        try exports.append(.{
1541                            .name = prefix,
1542                            .tag = .@"export",
1543                            .data = .{ .@"export" = .{
1544                                .kind = switch (flags & macho.EXPORT_SYMBOL_FLAGS_KIND_MASK) {
1545                                    macho.EXPORT_SYMBOL_FLAGS_KIND_REGULAR => .regular,
1546                                    macho.EXPORT_SYMBOL_FLAGS_KIND_ABSOLUTE => .absolute,
1547                                    macho.EXPORT_SYMBOL_FLAGS_KIND_THREAD_LOCAL => .tlv,
1548                                    else => unreachable,
1549                                },
1550                                .weak = flags & macho.EXPORT_SYMBOL_FLAGS_WEAK_DEFINITION != 0,
1551                                .vmoffset = vmoff,
1552                            } },
1553                        });
1554                    },
1555                }
1556            }
1557
1558            const nedges = try it.takeByte();
1559            for (0..nedges) |_| {
1560                const label = try it.readString();
1561                const off = try it.takeLeb128();
1562                const prefix_label = try std.fmt.allocPrint(arena, "{s}{s}", .{ prefix, label });
1563                const curr = it.stream.seek;
1564                it.stream.seek = off;
1565                try parseTrieNode(arena, it, prefix_label, exports);
1566                it.stream.seek = curr;
1567            }
1568        }
1569
1570        fn dumpSection(ctx: ObjectContext, sect: macho.section_64, writer: anytype) !void {
1571            const data = ctx.data[sect.offset..][0..sect.size];
1572            try writer.print("{s}", .{data});
1573        }
1574    };
1575
1576    fn parseAndDumpObject(step: *Step, check: Check, bytes: []const u8) ![]const u8 {
1577        const gpa = step.owner.allocator;
1578        const hdr = @as(*align(1) const macho.mach_header_64, @ptrCast(bytes.ptr)).*;
1579        if (hdr.magic != macho.MH_MAGIC_64) {
1580            return error.InvalidMagicNumber;
1581        }
1582
1583        var ctx = ObjectContext{ .gpa = gpa, .data = bytes, .header = hdr };
1584        try ctx.parse();
1585
1586        var output: std.Io.Writer.Allocating = .init(gpa);
1587        defer output.deinit();
1588        const writer = &output.writer;
1589
1590        switch (check.kind) {
1591            .headers => {
1592                try ObjectContext.dumpHeader(ctx.header, writer);
1593
1594                var it = try ctx.getLoadCommandIterator();
1595                var i: usize = 0;
1596                while (try it.next()) |cmd| {
1597                    try ObjectContext.dumpLoadCommand(cmd, i, writer);
1598                    try writer.writeByte('\n');
1599
1600                    i += 1;
1601                }
1602            },
1603
1604            .symtab => if (ctx.symtab.items.len > 0) {
1605                try ctx.dumpSymtab(writer);
1606            } else return step.fail("no symbol table found", .{}),
1607
1608            .indirect_symtab => if (ctx.symtab.items.len > 0 and ctx.indsymtab.items.len > 0) {
1609                try ctx.dumpIndirectSymtab(writer);
1610            } else return step.fail("no indirect symbol table found", .{}),
1611
1612            .dyld_rebase,
1613            .dyld_bind,
1614            .dyld_weak_bind,
1615            .dyld_lazy_bind,
1616            => {
1617                const cmd = try ctx.getLoadCommand(.DYLD_INFO_ONLY) orelse
1618                    return step.fail("no dyld info found", .{});
1619                const lc = cmd.cast(macho.dyld_info_command).?;
1620
1621                switch (check.kind) {
1622                    .dyld_rebase => if (lc.rebase_size > 0) {
1623                        const data = ctx.data[lc.rebase_off..][0..lc.rebase_size];
1624                        try writer.writeAll(dyld_rebase_label ++ "\n");
1625                        try ctx.dumpRebaseInfo(data, writer);
1626                    } else return step.fail("no rebase data found", .{}),
1627
1628                    .dyld_bind => if (lc.bind_size > 0) {
1629                        const data = ctx.data[lc.bind_off..][0..lc.bind_size];
1630                        try writer.writeAll(dyld_bind_label ++ "\n");
1631                        try ctx.dumpBindInfo(data, writer);
1632                    } else return step.fail("no bind data found", .{}),
1633
1634                    .dyld_weak_bind => if (lc.weak_bind_size > 0) {
1635                        const data = ctx.data[lc.weak_bind_off..][0..lc.weak_bind_size];
1636                        try writer.writeAll(dyld_weak_bind_label ++ "\n");
1637                        try ctx.dumpBindInfo(data, writer);
1638                    } else return step.fail("no weak bind data found", .{}),
1639
1640                    .dyld_lazy_bind => if (lc.lazy_bind_size > 0) {
1641                        const data = ctx.data[lc.lazy_bind_off..][0..lc.lazy_bind_size];
1642                        try writer.writeAll(dyld_lazy_bind_label ++ "\n");
1643                        try ctx.dumpBindInfo(data, writer);
1644                    } else return step.fail("no lazy bind data found", .{}),
1645
1646                    else => unreachable,
1647                }
1648            },
1649
1650            .exports => blk: {
1651                if (try ctx.getLoadCommand(.DYLD_INFO_ONLY)) |cmd| {
1652                    const lc = cmd.cast(macho.dyld_info_command).?;
1653                    if (lc.export_size > 0) {
1654                        const data = ctx.data[lc.export_off..][0..lc.export_size];
1655                        try writer.writeAll(exports_label ++ "\n");
1656                        try ctx.dumpExportsTrie(data, writer);
1657                        break :blk;
1658                    }
1659                }
1660                return step.fail("no exports data found", .{});
1661            },
1662
1663            .dump_section => {
1664                const name = mem.sliceTo(@as([*:0]const u8, @ptrCast(check.data.items.ptr + check.payload.dump_section)), 0);
1665                const sep_index = mem.indexOfScalar(u8, name, ',') orelse
1666                    return step.fail("invalid section name: {s}", .{name});
1667                const segname = name[0..sep_index];
1668                const sectname = name[sep_index + 1 ..];
1669                const sect = ctx.getSectionByName(segname, sectname) orelse
1670                    return step.fail("section '{s}' not found", .{name});
1671                try ctx.dumpSection(sect, writer);
1672            },
1673
1674            else => return step.fail("invalid check kind for MachO file format: {s}", .{@tagName(check.kind)}),
1675        }
1676
1677        return output.toOwnedSlice();
1678    }
1679};
1680
1681const ElfDumper = struct {
1682    const symtab_label = "symbol table";
1683    const dynamic_symtab_label = "dynamic symbol table";
1684    const dynamic_section_label = "dynamic section";
1685    const archive_symtab_label = "archive symbol table";
1686
1687    fn parseAndDump(step: *Step, check: Check, bytes: []const u8) ![]const u8 {
1688        return parseAndDumpArchive(step, check, bytes) catch |err| switch (err) {
1689            error.InvalidArchiveMagicNumber => try parseAndDumpObject(step, check, bytes),
1690            else => |e| return e,
1691        };
1692    }
1693
1694    fn parseAndDumpArchive(step: *Step, check: Check, bytes: []const u8) ![]const u8 {
1695        const gpa = step.owner.allocator;
1696        var reader: std.Io.Reader = .fixed(bytes);
1697
1698        const magic = try reader.takeArray(elf.ARMAG.len);
1699        if (!mem.eql(u8, magic, elf.ARMAG)) {
1700            return error.InvalidArchiveMagicNumber;
1701        }
1702
1703        var ctx = ArchiveContext{
1704            .gpa = gpa,
1705            .data = bytes,
1706            .strtab = &[0]u8{},
1707        };
1708        defer {
1709            for (ctx.objects.items) |*object| {
1710                gpa.free(object.name);
1711            }
1712            ctx.objects.deinit(gpa);
1713        }
1714
1715        while (true) {
1716            if (reader.seek >= ctx.data.len) break;
1717            if (!mem.isAligned(reader.seek, 2)) reader.seek += 1;
1718
1719            const hdr = try reader.takeStruct(elf.ar_hdr, .little);
1720
1721            if (!mem.eql(u8, &hdr.ar_fmag, elf.ARFMAG)) return error.InvalidArchiveHeaderMagicNumber;
1722
1723            const size = try hdr.size();
1724            defer reader.seek += size;
1725
1726            if (hdr.isSymtab()) {
1727                try ctx.parseSymtab(ctx.data[reader.seek..][0..size], .p32);
1728                continue;
1729            }
1730            if (hdr.isSymtab64()) {
1731                try ctx.parseSymtab(ctx.data[reader.seek..][0..size], .p64);
1732                continue;
1733            }
1734            if (hdr.isStrtab()) {
1735                ctx.strtab = ctx.data[reader.seek..][0..size];
1736                continue;
1737            }
1738            if (hdr.isSymdef() or hdr.isSymdefSorted()) continue;
1739
1740            const name = if (hdr.name()) |name|
1741                try gpa.dupe(u8, name)
1742            else if (try hdr.nameOffset()) |off|
1743                try gpa.dupe(u8, ctx.getString(off))
1744            else
1745                unreachable;
1746
1747            try ctx.objects.append(gpa, .{ .name = name, .off = reader.seek, .len = size });
1748        }
1749
1750        var output: std.Io.Writer.Allocating = .init(gpa);
1751        defer output.deinit();
1752        const writer = &output.writer;
1753
1754        switch (check.kind) {
1755            .archive_symtab => if (ctx.symtab.items.len > 0) {
1756                try ctx.dumpSymtab(writer);
1757            } else return step.fail("no archive symbol table found", .{}),
1758
1759            else => if (ctx.objects.items.len > 0) {
1760                try ctx.dumpObjects(step, check, writer);
1761            } else return step.fail("empty archive", .{}),
1762        }
1763
1764        return output.toOwnedSlice();
1765    }
1766
1767    const ArchiveContext = struct {
1768        gpa: Allocator,
1769        data: []const u8,
1770        symtab: std.ArrayList(ArSymtabEntry) = .empty,
1771        strtab: []const u8,
1772        objects: std.ArrayList(struct { name: []const u8, off: usize, len: usize }) = .empty,
1773
1774        fn parseSymtab(ctx: *ArchiveContext, raw: []const u8, ptr_width: enum { p32, p64 }) !void {
1775            var reader: std.Io.Reader = .fixed(raw);
1776            const num = switch (ptr_width) {
1777                .p32 => try reader.takeInt(u32, .big),
1778                .p64 => try reader.takeInt(u64, .big),
1779            };
1780            const ptr_size: usize = switch (ptr_width) {
1781                .p32 => @sizeOf(u32),
1782                .p64 => @sizeOf(u64),
1783            };
1784            const strtab_off = (num + 1) * ptr_size;
1785            const strtab_len = raw.len - strtab_off;
1786            const strtab = raw[strtab_off..][0..strtab_len];
1787
1788            try ctx.symtab.ensureTotalCapacityPrecise(ctx.gpa, num);
1789
1790            var stroff: usize = 0;
1791            for (0..num) |_| {
1792                const off = switch (ptr_width) {
1793                    .p32 => try reader.takeInt(u32, .big),
1794                    .p64 => try reader.takeInt(u64, .big),
1795                };
1796                const name = mem.sliceTo(@as([*:0]const u8, @ptrCast(strtab.ptr + stroff)), 0);
1797                stroff += name.len + 1;
1798                ctx.symtab.appendAssumeCapacity(.{ .off = off, .name = name });
1799            }
1800        }
1801
1802        fn dumpSymtab(ctx: ArchiveContext, writer: anytype) !void {
1803            var files = std.AutoHashMap(usize, []const u8).init(ctx.gpa);
1804            defer files.deinit();
1805            try files.ensureUnusedCapacity(@intCast(ctx.objects.items.len));
1806
1807            for (ctx.objects.items) |object| {
1808                files.putAssumeCapacityNoClobber(object.off - @sizeOf(elf.ar_hdr), object.name);
1809            }
1810
1811            var symbols = std.AutoArrayHashMap(usize, std.array_list.Managed([]const u8)).init(ctx.gpa);
1812            defer {
1813                for (symbols.values()) |*value| {
1814                    value.deinit();
1815                }
1816                symbols.deinit();
1817            }
1818
1819            for (ctx.symtab.items) |entry| {
1820                const gop = try symbols.getOrPut(@intCast(entry.off));
1821                if (!gop.found_existing) {
1822                    gop.value_ptr.* = std.array_list.Managed([]const u8).init(ctx.gpa);
1823                }
1824                try gop.value_ptr.append(entry.name);
1825            }
1826
1827            try writer.print("{s}\n", .{archive_symtab_label});
1828            for (symbols.keys(), symbols.values()) |off, values| {
1829                try writer.print("in object {s}\n", .{files.get(off).?});
1830                for (values.items) |value| {
1831                    try writer.print("{s}\n", .{value});
1832                }
1833            }
1834        }
1835
1836        fn dumpObjects(ctx: ArchiveContext, step: *Step, check: Check, writer: anytype) !void {
1837            for (ctx.objects.items) |object| {
1838                try writer.print("object {s}\n", .{object.name});
1839                const output = try parseAndDumpObject(step, check, ctx.data[object.off..][0..object.len]);
1840                defer ctx.gpa.free(output);
1841                try writer.print("{s}\n", .{output});
1842            }
1843        }
1844
1845        fn getString(ctx: ArchiveContext, off: u32) []const u8 {
1846            assert(off < ctx.strtab.len);
1847            const name = mem.sliceTo(@as([*:'\n']const u8, @ptrCast(ctx.strtab.ptr + off)), 0);
1848            return name[0 .. name.len - 1];
1849        }
1850
1851        const ArSymtabEntry = struct {
1852            name: [:0]const u8,
1853            off: u64,
1854        };
1855    };
1856
1857    fn parseAndDumpObject(step: *Step, check: Check, bytes: []const u8) ![]const u8 {
1858        const gpa = step.owner.allocator;
1859
1860        // `std.elf.Header` takes care of endianness issues for us.
1861        var reader: std.Io.Reader = .fixed(bytes);
1862        const hdr = try elf.Header.read(&reader);
1863
1864        var shdrs = try gpa.alloc(elf.Elf64_Shdr, hdr.shnum);
1865        defer gpa.free(shdrs);
1866        {
1867            var shdr_it = hdr.iterateSectionHeadersBuffer(bytes);
1868            var shdr_i: usize = 0;
1869            while (try shdr_it.next()) |shdr| : (shdr_i += 1) shdrs[shdr_i] = shdr;
1870        }
1871
1872        var phdrs = try gpa.alloc(elf.Elf64_Phdr, hdr.shnum);
1873        defer gpa.free(phdrs);
1874        {
1875            var phdr_it = hdr.iterateProgramHeadersBuffer(bytes);
1876            var phdr_i: usize = 0;
1877            while (try phdr_it.next()) |phdr| : (phdr_i += 1) phdrs[phdr_i] = phdr;
1878        }
1879
1880        var ctx = ObjectContext{
1881            .gpa = gpa,
1882            .data = bytes,
1883            .hdr = hdr,
1884            .shdrs = shdrs,
1885            .phdrs = phdrs,
1886            .shstrtab = undefined,
1887        };
1888        ctx.shstrtab = ctx.getSectionContents(ctx.hdr.shstrndx);
1889
1890        defer gpa.free(ctx.symtab.symbols);
1891        defer gpa.free(ctx.dysymtab.symbols);
1892        defer gpa.free(ctx.dyns);
1893
1894        for (ctx.shdrs, 0..) |shdr, i| switch (shdr.sh_type) {
1895            elf.SHT_SYMTAB, elf.SHT_DYNSYM => {
1896                const raw = ctx.getSectionContents(i);
1897                const nsyms = @divExact(raw.len, @sizeOf(elf.Elf64_Sym));
1898                const symbols = try gpa.alloc(elf.Elf64_Sym, nsyms);
1899
1900                var r: std.Io.Reader = .fixed(raw);
1901                for (0..nsyms) |si| symbols[si] = r.takeStruct(elf.Elf64_Sym, ctx.hdr.endian) catch unreachable;
1902
1903                const strings = ctx.getSectionContents(shdr.sh_link);
1904
1905                switch (shdr.sh_type) {
1906                    elf.SHT_SYMTAB => {
1907                        ctx.symtab = .{
1908                            .symbols = symbols,
1909                            .strings = strings,
1910                        };
1911                    },
1912                    elf.SHT_DYNSYM => {
1913                        ctx.dysymtab = .{
1914                            .symbols = symbols,
1915                            .strings = strings,
1916                        };
1917                    },
1918                    else => unreachable,
1919                }
1920            },
1921            elf.SHT_DYNAMIC => {
1922                const raw = ctx.getSectionContents(i);
1923                const ndyns = @divExact(raw.len, @sizeOf(elf.Elf64_Dyn));
1924                const dyns = try gpa.alloc(elf.Elf64_Dyn, ndyns);
1925
1926                var r: std.Io.Reader = .fixed(raw);
1927                for (0..ndyns) |si| dyns[si] = r.takeStruct(elf.Elf64_Dyn, ctx.hdr.endian) catch unreachable;
1928
1929                ctx.dyns = dyns;
1930                ctx.dyns_strings = ctx.getSectionContents(shdr.sh_link);
1931            },
1932
1933            else => {},
1934        };
1935
1936        var output: std.Io.Writer.Allocating = .init(gpa);
1937        defer output.deinit();
1938        const writer = &output.writer;
1939
1940        switch (check.kind) {
1941            .headers => {
1942                try ctx.dumpHeader(writer);
1943                try ctx.dumpShdrs(writer);
1944                try ctx.dumpPhdrs(writer);
1945            },
1946
1947            .symtab => if (ctx.symtab.symbols.len > 0) {
1948                try ctx.dumpSymtab(.symtab, writer);
1949            } else return step.fail("no symbol table found", .{}),
1950
1951            .dynamic_symtab => if (ctx.dysymtab.symbols.len > 0) {
1952                try ctx.dumpSymtab(.dysymtab, writer);
1953            } else return step.fail("no dynamic symbol table found", .{}),
1954
1955            .dynamic_section => if (ctx.dyns.len > 0) {
1956                try ctx.dumpDynamicSection(writer);
1957            } else return step.fail("no dynamic section found", .{}),
1958
1959            .dump_section => {
1960                const name = mem.sliceTo(@as([*:0]const u8, @ptrCast(check.data.items.ptr + check.payload.dump_section)), 0);
1961                const shndx = ctx.getSectionByName(name) orelse return step.fail("no '{s}' section found", .{name});
1962                try ctx.dumpSection(shndx, writer);
1963            },
1964
1965            else => return step.fail("invalid check kind for ELF file format: {s}", .{@tagName(check.kind)}),
1966        }
1967
1968        return output.toOwnedSlice();
1969    }
1970
1971    const ObjectContext = struct {
1972        gpa: Allocator,
1973        data: []const u8,
1974        hdr: elf.Header,
1975        shdrs: []const elf.Elf64_Shdr,
1976        phdrs: []const elf.Elf64_Phdr,
1977        shstrtab: []const u8,
1978        symtab: Symtab = .{},
1979        dysymtab: Symtab = .{},
1980        dyns: []const elf.Elf64_Dyn = &.{},
1981        dyns_strings: []const u8 = &.{},
1982
1983        fn dumpHeader(ctx: ObjectContext, writer: anytype) !void {
1984            try writer.writeAll("header\n");
1985            try writer.print("type {s}\n", .{@tagName(ctx.hdr.type)});
1986            try writer.print("entry {x}\n", .{ctx.hdr.entry});
1987        }
1988
1989        fn dumpPhdrs(ctx: ObjectContext, writer: anytype) !void {
1990            if (ctx.phdrs.len == 0) return;
1991
1992            try writer.writeAll("program headers\n");
1993
1994            for (ctx.phdrs, 0..) |phdr, phndx| {
1995                try writer.print("phdr {d}\n", .{phndx});
1996                try writer.print("type {f}\n", .{fmtPhType(phdr.p_type)});
1997                try writer.print("vaddr {x}\n", .{phdr.p_vaddr});
1998                try writer.print("paddr {x}\n", .{phdr.p_paddr});
1999                try writer.print("offset {x}\n", .{phdr.p_offset});
2000                try writer.print("memsz {x}\n", .{phdr.p_memsz});
2001                try writer.print("filesz {x}\n", .{phdr.p_filesz});
2002                try writer.print("align {x}\n", .{phdr.p_align});
2003
2004                {
2005                    const flags = phdr.p_flags;
2006                    try writer.writeAll("flags");
2007                    if (flags > 0) try writer.writeByte(' ');
2008                    if (flags & elf.PF_R != 0) {
2009                        try writer.writeByte('R');
2010                    }
2011                    if (flags & elf.PF_W != 0) {
2012                        try writer.writeByte('W');
2013                    }
2014                    if (flags & elf.PF_X != 0) {
2015                        try writer.writeByte('E');
2016                    }
2017                    if (flags & elf.PF_MASKOS != 0) {
2018                        try writer.writeAll("OS");
2019                    }
2020                    if (flags & elf.PF_MASKPROC != 0) {
2021                        try writer.writeAll("PROC");
2022                    }
2023                    try writer.writeByte('\n');
2024                }
2025            }
2026        }
2027
2028        fn dumpShdrs(ctx: ObjectContext, writer: anytype) !void {
2029            if (ctx.shdrs.len == 0) return;
2030
2031            try writer.writeAll("section headers\n");
2032
2033            for (ctx.shdrs, 0..) |shdr, shndx| {
2034                try writer.print("shdr {d}\n", .{shndx});
2035                try writer.print("name {s}\n", .{ctx.getSectionName(shndx)});
2036                try writer.print("type {f}\n", .{fmtShType(shdr.sh_type)});
2037                try writer.print("addr {x}\n", .{shdr.sh_addr});
2038                try writer.print("offset {x}\n", .{shdr.sh_offset});
2039                try writer.print("size {x}\n", .{shdr.sh_size});
2040                try writer.print("addralign {x}\n", .{shdr.sh_addralign});
2041                // TODO dump formatted sh_flags
2042            }
2043        }
2044
2045        fn dumpDynamicSection(ctx: ObjectContext, writer: anytype) !void {
2046            try writer.writeAll(ElfDumper.dynamic_section_label ++ "\n");
2047
2048            for (ctx.dyns) |entry| {
2049                const key = @as(u64, @bitCast(entry.d_tag));
2050                const value = entry.d_val;
2051
2052                const key_str = switch (key) {
2053                    elf.DT_NEEDED => "NEEDED",
2054                    elf.DT_SONAME => "SONAME",
2055                    elf.DT_INIT_ARRAY => "INIT_ARRAY",
2056                    elf.DT_INIT_ARRAYSZ => "INIT_ARRAYSZ",
2057                    elf.DT_FINI_ARRAY => "FINI_ARRAY",
2058                    elf.DT_FINI_ARRAYSZ => "FINI_ARRAYSZ",
2059                    elf.DT_HASH => "HASH",
2060                    elf.DT_GNU_HASH => "GNU_HASH",
2061                    elf.DT_STRTAB => "STRTAB",
2062                    elf.DT_SYMTAB => "SYMTAB",
2063                    elf.DT_STRSZ => "STRSZ",
2064                    elf.DT_SYMENT => "SYMENT",
2065                    elf.DT_PLTGOT => "PLTGOT",
2066                    elf.DT_PLTRELSZ => "PLTRELSZ",
2067                    elf.DT_PLTREL => "PLTREL",
2068                    elf.DT_JMPREL => "JMPREL",
2069                    elf.DT_RELA => "RELA",
2070                    elf.DT_RELASZ => "RELASZ",
2071                    elf.DT_RELAENT => "RELAENT",
2072                    elf.DT_VERDEF => "VERDEF",
2073                    elf.DT_VERDEFNUM => "VERDEFNUM",
2074                    elf.DT_FLAGS => "FLAGS",
2075                    elf.DT_FLAGS_1 => "FLAGS_1",
2076                    elf.DT_VERNEED => "VERNEED",
2077                    elf.DT_VERNEEDNUM => "VERNEEDNUM",
2078                    elf.DT_VERSYM => "VERSYM",
2079                    elf.DT_RELACOUNT => "RELACOUNT",
2080                    elf.DT_RPATH => "RPATH",
2081                    elf.DT_RUNPATH => "RUNPATH",
2082                    elf.DT_INIT => "INIT",
2083                    elf.DT_FINI => "FINI",
2084                    elf.DT_NULL => "NULL",
2085                    else => "UNKNOWN",
2086                };
2087                try writer.print("{s}", .{key_str});
2088
2089                switch (key) {
2090                    elf.DT_NEEDED,
2091                    elf.DT_SONAME,
2092                    elf.DT_RPATH,
2093                    elf.DT_RUNPATH,
2094                    => {
2095                        const name = getString(ctx.dyns_strings, @intCast(value));
2096                        try writer.print(" {s}", .{name});
2097                    },
2098
2099                    elf.DT_INIT_ARRAY,
2100                    elf.DT_FINI_ARRAY,
2101                    elf.DT_HASH,
2102                    elf.DT_GNU_HASH,
2103                    elf.DT_STRTAB,
2104                    elf.DT_SYMTAB,
2105                    elf.DT_PLTGOT,
2106                    elf.DT_JMPREL,
2107                    elf.DT_RELA,
2108                    elf.DT_VERDEF,
2109                    elf.DT_VERNEED,
2110                    elf.DT_VERSYM,
2111                    elf.DT_INIT,
2112                    elf.DT_FINI,
2113                    elf.DT_NULL,
2114                    => try writer.print(" {x}", .{value}),
2115
2116                    elf.DT_INIT_ARRAYSZ,
2117                    elf.DT_FINI_ARRAYSZ,
2118                    elf.DT_STRSZ,
2119                    elf.DT_SYMENT,
2120                    elf.DT_PLTRELSZ,
2121                    elf.DT_RELASZ,
2122                    elf.DT_RELAENT,
2123                    elf.DT_RELACOUNT,
2124                    => try writer.print(" {d}", .{value}),
2125
2126                    elf.DT_PLTREL => try writer.writeAll(switch (value) {
2127                        elf.DT_REL => " REL",
2128                        elf.DT_RELA => " RELA",
2129                        else => " UNKNOWN",
2130                    }),
2131
2132                    elf.DT_FLAGS => if (value > 0) {
2133                        if (value & elf.DF_ORIGIN != 0) try writer.writeAll(" ORIGIN");
2134                        if (value & elf.DF_SYMBOLIC != 0) try writer.writeAll(" SYMBOLIC");
2135                        if (value & elf.DF_TEXTREL != 0) try writer.writeAll(" TEXTREL");
2136                        if (value & elf.DF_BIND_NOW != 0) try writer.writeAll(" BIND_NOW");
2137                        if (value & elf.DF_STATIC_TLS != 0) try writer.writeAll(" STATIC_TLS");
2138                    },
2139
2140                    elf.DT_FLAGS_1 => if (value > 0) {
2141                        if (value & elf.DF_1_NOW != 0) try writer.writeAll(" NOW");
2142                        if (value & elf.DF_1_GLOBAL != 0) try writer.writeAll(" GLOBAL");
2143                        if (value & elf.DF_1_GROUP != 0) try writer.writeAll(" GROUP");
2144                        if (value & elf.DF_1_NODELETE != 0) try writer.writeAll(" NODELETE");
2145                        if (value & elf.DF_1_LOADFLTR != 0) try writer.writeAll(" LOADFLTR");
2146                        if (value & elf.DF_1_INITFIRST != 0) try writer.writeAll(" INITFIRST");
2147                        if (value & elf.DF_1_NOOPEN != 0) try writer.writeAll(" NOOPEN");
2148                        if (value & elf.DF_1_ORIGIN != 0) try writer.writeAll(" ORIGIN");
2149                        if (value & elf.DF_1_DIRECT != 0) try writer.writeAll(" DIRECT");
2150                        if (value & elf.DF_1_TRANS != 0) try writer.writeAll(" TRANS");
2151                        if (value & elf.DF_1_INTERPOSE != 0) try writer.writeAll(" INTERPOSE");
2152                        if (value & elf.DF_1_NODEFLIB != 0) try writer.writeAll(" NODEFLIB");
2153                        if (value & elf.DF_1_NODUMP != 0) try writer.writeAll(" NODUMP");
2154                        if (value & elf.DF_1_CONFALT != 0) try writer.writeAll(" CONFALT");
2155                        if (value & elf.DF_1_ENDFILTEE != 0) try writer.writeAll(" ENDFILTEE");
2156                        if (value & elf.DF_1_DISPRELDNE != 0) try writer.writeAll(" DISPRELDNE");
2157                        if (value & elf.DF_1_DISPRELPND != 0) try writer.writeAll(" DISPRELPND");
2158                        if (value & elf.DF_1_NODIRECT != 0) try writer.writeAll(" NODIRECT");
2159                        if (value & elf.DF_1_IGNMULDEF != 0) try writer.writeAll(" IGNMULDEF");
2160                        if (value & elf.DF_1_NOKSYMS != 0) try writer.writeAll(" NOKSYMS");
2161                        if (value & elf.DF_1_NOHDR != 0) try writer.writeAll(" NOHDR");
2162                        if (value & elf.DF_1_EDITED != 0) try writer.writeAll(" EDITED");
2163                        if (value & elf.DF_1_NORELOC != 0) try writer.writeAll(" NORELOC");
2164                        if (value & elf.DF_1_SYMINTPOSE != 0) try writer.writeAll(" SYMINTPOSE");
2165                        if (value & elf.DF_1_GLOBAUDIT != 0) try writer.writeAll(" GLOBAUDIT");
2166                        if (value & elf.DF_1_SINGLETON != 0) try writer.writeAll(" SINGLETON");
2167                        if (value & elf.DF_1_STUB != 0) try writer.writeAll(" STUB");
2168                        if (value & elf.DF_1_PIE != 0) try writer.writeAll(" PIE");
2169                    },
2170
2171                    else => try writer.print(" {x}", .{value}),
2172                }
2173                try writer.writeByte('\n');
2174            }
2175        }
2176
2177        fn dumpSymtab(ctx: ObjectContext, comptime @"type": enum { symtab, dysymtab }, writer: anytype) !void {
2178            const symtab = switch (@"type") {
2179                .symtab => ctx.symtab,
2180                .dysymtab => ctx.dysymtab,
2181            };
2182
2183            try writer.writeAll(switch (@"type") {
2184                .symtab => symtab_label,
2185                .dysymtab => dynamic_symtab_label,
2186            } ++ "\n");
2187
2188            for (symtab.symbols, 0..) |sym, index| {
2189                try writer.print("{x} {x}", .{ sym.st_value, sym.st_size });
2190
2191                {
2192                    if (elf.SHN_LORESERVE <= sym.st_shndx and sym.st_shndx < elf.SHN_HIRESERVE) {
2193                        if (elf.SHN_LOPROC <= sym.st_shndx and sym.st_shndx < elf.SHN_HIPROC) {
2194                            try writer.print(" LO+{d}", .{sym.st_shndx - elf.SHN_LOPROC});
2195                        } else {
2196                            const sym_ndx = switch (sym.st_shndx) {
2197                                elf.SHN_ABS => "ABS",
2198                                elf.SHN_COMMON => "COM",
2199                                elf.SHN_LIVEPATCH => "LIV",
2200                                else => "UNK",
2201                            };
2202                            try writer.print(" {s}", .{sym_ndx});
2203                        }
2204                    } else if (sym.st_shndx == elf.SHN_UNDEF) {
2205                        try writer.writeAll(" UND");
2206                    } else {
2207                        try writer.print(" {x}", .{sym.st_shndx});
2208                    }
2209                }
2210
2211                blk: {
2212                    const tt = sym.st_type();
2213                    const sym_type = switch (tt) {
2214                        elf.STT_NOTYPE => "NOTYPE",
2215                        elf.STT_OBJECT => "OBJECT",
2216                        elf.STT_FUNC => "FUNC",
2217                        elf.STT_SECTION => "SECTION",
2218                        elf.STT_FILE => "FILE",
2219                        elf.STT_COMMON => "COMMON",
2220                        elf.STT_TLS => "TLS",
2221                        elf.STT_NUM => "NUM",
2222                        elf.STT_GNU_IFUNC => "IFUNC",
2223                        else => if (elf.STT_LOPROC <= tt and tt < elf.STT_HIPROC) {
2224                            break :blk try writer.print(" LOPROC+{d}", .{tt - elf.STT_LOPROC});
2225                        } else if (elf.STT_LOOS <= tt and tt < elf.STT_HIOS) {
2226                            break :blk try writer.print(" LOOS+{d}", .{tt - elf.STT_LOOS});
2227                        } else "UNK",
2228                    };
2229                    try writer.print(" {s}", .{sym_type});
2230                }
2231
2232                blk: {
2233                    const bind = sym.st_bind();
2234                    const sym_bind = switch (bind) {
2235                        elf.STB_LOCAL => "LOCAL",
2236                        elf.STB_GLOBAL => "GLOBAL",
2237                        elf.STB_WEAK => "WEAK",
2238                        elf.STB_NUM => "NUM",
2239                        else => if (elf.STB_LOPROC <= bind and bind < elf.STB_HIPROC) {
2240                            break :blk try writer.print(" LOPROC+{d}", .{bind - elf.STB_LOPROC});
2241                        } else if (elf.STB_LOOS <= bind and bind < elf.STB_HIOS) {
2242                            break :blk try writer.print(" LOOS+{d}", .{bind - elf.STB_LOOS});
2243                        } else "UNKNOWN",
2244                    };
2245                    try writer.print(" {s}", .{sym_bind});
2246                }
2247
2248                const sym_vis = @as(elf.STV, @enumFromInt(@as(u3, @truncate(sym.st_other))));
2249                try writer.print(" {s}", .{@tagName(sym_vis)});
2250
2251                const sym_name = switch (sym.st_type()) {
2252                    elf.STT_SECTION => ctx.getSectionName(sym.st_shndx),
2253                    else => symtab.getName(index).?,
2254                };
2255                try writer.print(" {s}\n", .{sym_name});
2256            }
2257        }
2258
2259        fn dumpSection(ctx: ObjectContext, shndx: usize, writer: anytype) !void {
2260            const data = ctx.getSectionContents(shndx);
2261            try writer.print("{s}", .{data});
2262        }
2263
2264        inline fn getSectionName(ctx: ObjectContext, shndx: usize) []const u8 {
2265            const shdr = ctx.shdrs[shndx];
2266            return getString(ctx.shstrtab, shdr.sh_name);
2267        }
2268
2269        fn getSectionContents(ctx: ObjectContext, shndx: usize) []const u8 {
2270            const shdr = ctx.shdrs[shndx];
2271            assert(shdr.sh_offset < ctx.data.len);
2272            assert(shdr.sh_offset + shdr.sh_size <= ctx.data.len);
2273            return ctx.data[shdr.sh_offset..][0..shdr.sh_size];
2274        }
2275
2276        fn getSectionByName(ctx: ObjectContext, name: []const u8) ?usize {
2277            for (0..ctx.shdrs.len) |shndx| {
2278                if (mem.eql(u8, ctx.getSectionName(shndx), name)) return shndx;
2279            } else return null;
2280        }
2281    };
2282
2283    const Symtab = struct {
2284        symbols: []const elf.Elf64_Sym = &.{},
2285        strings: []const u8 = &.{},
2286
2287        fn get(st: Symtab, index: usize) ?elf.Elf64_Sym {
2288            if (index >= st.symbols.len) return null;
2289            return st.symbols[index];
2290        }
2291
2292        fn getName(st: Symtab, index: usize) ?[]const u8 {
2293            const sym = st.get(index) orelse return null;
2294            return getString(st.strings, sym.st_name);
2295        }
2296    };
2297
2298    fn getString(strtab: []const u8, off: u32) []const u8 {
2299        assert(off < strtab.len);
2300        return mem.sliceTo(@as([*:0]const u8, @ptrCast(strtab.ptr + off)), 0);
2301    }
2302
2303    fn fmtShType(sh_type: u32) std.fmt.Alt(u32, formatShType) {
2304        return .{ .data = sh_type };
2305    }
2306
2307    fn formatShType(sh_type: u32, writer: *Writer) Writer.Error!void {
2308        const name = switch (sh_type) {
2309            elf.SHT_NULL => "NULL",
2310            elf.SHT_PROGBITS => "PROGBITS",
2311            elf.SHT_SYMTAB => "SYMTAB",
2312            elf.SHT_STRTAB => "STRTAB",
2313            elf.SHT_RELA => "RELA",
2314            elf.SHT_HASH => "HASH",
2315            elf.SHT_DYNAMIC => "DYNAMIC",
2316            elf.SHT_NOTE => "NOTE",
2317            elf.SHT_NOBITS => "NOBITS",
2318            elf.SHT_REL => "REL",
2319            elf.SHT_SHLIB => "SHLIB",
2320            elf.SHT_DYNSYM => "DYNSYM",
2321            elf.SHT_INIT_ARRAY => "INIT_ARRAY",
2322            elf.SHT_FINI_ARRAY => "FINI_ARRAY",
2323            elf.SHT_PREINIT_ARRAY => "PREINIT_ARRAY",
2324            elf.SHT_GROUP => "GROUP",
2325            elf.SHT_SYMTAB_SHNDX => "SYMTAB_SHNDX",
2326            elf.SHT_X86_64_UNWIND => "X86_64_UNWIND",
2327            elf.SHT_LLVM_ADDRSIG => "LLVM_ADDRSIG",
2328            elf.SHT_GNU_HASH => "GNU_HASH",
2329            elf.SHT_GNU_VERDEF => "VERDEF",
2330            elf.SHT_GNU_VERNEED => "VERNEED",
2331            elf.SHT_GNU_VERSYM => "VERSYM",
2332            else => if (elf.SHT_LOOS <= sh_type and sh_type < elf.SHT_HIOS) {
2333                return try writer.print("LOOS+0x{x}", .{sh_type - elf.SHT_LOOS});
2334            } else if (elf.SHT_LOPROC <= sh_type and sh_type < elf.SHT_HIPROC) {
2335                return try writer.print("LOPROC+0x{x}", .{sh_type - elf.SHT_LOPROC});
2336            } else if (elf.SHT_LOUSER <= sh_type and sh_type < elf.SHT_HIUSER) {
2337                return try writer.print("LOUSER+0x{x}", .{sh_type - elf.SHT_LOUSER});
2338            } else "UNKNOWN",
2339        };
2340        try writer.writeAll(name);
2341    }
2342
2343    fn fmtPhType(ph_type: u32) std.fmt.Alt(u32, formatPhType) {
2344        return .{ .data = ph_type };
2345    }
2346
2347    fn formatPhType(ph_type: u32, writer: *Writer) Writer.Error!void {
2348        const p_type = switch (ph_type) {
2349            elf.PT_NULL => "NULL",
2350            elf.PT_LOAD => "LOAD",
2351            elf.PT_DYNAMIC => "DYNAMIC",
2352            elf.PT_INTERP => "INTERP",
2353            elf.PT_NOTE => "NOTE",
2354            elf.PT_SHLIB => "SHLIB",
2355            elf.PT_PHDR => "PHDR",
2356            elf.PT_TLS => "TLS",
2357            elf.PT_NUM => "NUM",
2358            elf.PT_GNU_EH_FRAME => "GNU_EH_FRAME",
2359            elf.PT_GNU_STACK => "GNU_STACK",
2360            elf.PT_GNU_RELRO => "GNU_RELRO",
2361            else => if (elf.PT_LOOS <= ph_type and ph_type < elf.PT_HIOS) {
2362                return try writer.print("LOOS+0x{x}", .{ph_type - elf.PT_LOOS});
2363            } else if (elf.PT_LOPROC <= ph_type and ph_type < elf.PT_HIPROC) {
2364                return try writer.print("LOPROC+0x{x}", .{ph_type - elf.PT_LOPROC});
2365            } else "UNKNOWN",
2366        };
2367        try writer.writeAll(p_type);
2368    }
2369};
2370
2371const WasmDumper = struct {
2372    const symtab_label = "symbols";
2373
2374    fn parseAndDump(step: *Step, check: Check, bytes: []const u8) ![]const u8 {
2375        const gpa = step.owner.allocator;
2376        var reader: std.Io.Reader = .fixed(bytes);
2377
2378        const buf = try reader.takeArray(8);
2379        if (!mem.eql(u8, buf[0..4], &std.wasm.magic)) {
2380            return error.InvalidMagicByte;
2381        }
2382        if (!mem.eql(u8, buf[4..], &std.wasm.version)) {
2383            return error.UnsupportedWasmVersion;
2384        }
2385
2386        var output: std.Io.Writer.Allocating = .init(gpa);
2387        defer output.deinit();
2388        parseAndDumpInner(step, check, bytes, &reader, &output.writer) catch |err| switch (err) {
2389            error.EndOfStream => try output.writer.writeAll("\n<UnexpectedEndOfStream>"),
2390            else => |e| return e,
2391        };
2392        return output.toOwnedSlice();
2393    }
2394
2395    fn parseAndDumpInner(
2396        step: *Step,
2397        check: Check,
2398        bytes: []const u8,
2399        reader: *std.Io.Reader,
2400        writer: *std.Io.Writer,
2401    ) !void {
2402        switch (check.kind) {
2403            .headers => {
2404                while (reader.takeByte()) |current_byte| {
2405                    const section = std.enums.fromInt(std.wasm.Section, current_byte) orelse {
2406                        return step.fail("Found invalid section id '{d}'", .{current_byte});
2407                    };
2408
2409                    const section_length = try reader.takeLeb128(u32);
2410                    try parseAndDumpSection(step, section, bytes[reader.seek..][0..section_length], writer);
2411                    reader.seek += section_length;
2412                } else |_| {} // reached end of stream
2413            },
2414
2415            else => return step.fail("invalid check kind for Wasm file format: {s}", .{@tagName(check.kind)}),
2416        }
2417    }
2418
2419    fn parseAndDumpSection(
2420        step: *Step,
2421        section: std.wasm.Section,
2422        data: []const u8,
2423        writer: *std.Io.Writer,
2424    ) !void {
2425        var reader: std.Io.Reader = .fixed(data);
2426
2427        try writer.print(
2428            \\Section {s}
2429            \\size {d}
2430        , .{ @tagName(section), data.len });
2431
2432        switch (section) {
2433            .type,
2434            .import,
2435            .function,
2436            .table,
2437            .memory,
2438            .global,
2439            .@"export",
2440            .element,
2441            .code,
2442            .data,
2443            => {
2444                const entries = try reader.takeLeb128(u32);
2445                try writer.print("\nentries {d}\n", .{entries});
2446                try parseSection(step, section, data[reader.seek..], entries, writer);
2447            },
2448            .custom => {
2449                const name_length = try reader.takeLeb128(u32);
2450                const name = data[reader.seek..][0..name_length];
2451                reader.seek += name_length;
2452                try writer.print("\nname {s}\n", .{name});
2453
2454                if (mem.eql(u8, name, "name")) {
2455                    try parseDumpNames(step, &reader, writer, data);
2456                } else if (mem.eql(u8, name, "producers")) {
2457                    try parseDumpProducers(&reader, writer, data);
2458                } else if (mem.eql(u8, name, "target_features")) {
2459                    try parseDumpFeatures(&reader, writer, data);
2460                }
2461                // TODO: Implement parsing and dumping other custom sections (such as relocations)
2462            },
2463            .start => {
2464                const start = try reader.takeLeb128(u32);
2465                try writer.print("\nstart {d}\n", .{start});
2466            },
2467            .data_count => {
2468                const count = try reader.takeLeb128(u32);
2469                try writer.print("\ncount {d}\n", .{count});
2470            },
2471            else => {}, // skip unknown sections
2472        }
2473    }
2474
2475    fn parseSection(step: *Step, section: std.wasm.Section, data: []const u8, entries: u32, writer: anytype) !void {
2476        var reader: std.Io.Reader = .fixed(data);
2477
2478        switch (section) {
2479            .type => {
2480                var i: u32 = 0;
2481                while (i < entries) : (i += 1) {
2482                    const func_type = try reader.takeByte();
2483                    if (func_type != std.wasm.function_type) {
2484                        return step.fail("expected function type, found byte '{d}'", .{func_type});
2485                    }
2486                    const params = try reader.takeLeb128(u32);
2487                    try writer.print("params {d}\n", .{params});
2488                    var index: u32 = 0;
2489                    while (index < params) : (index += 1) {
2490                        _ = try parseDumpType(step, std.wasm.Valtype, &reader, writer);
2491                    } else index = 0;
2492                    const returns = try reader.takeLeb128(u32);
2493                    try writer.print("returns {d}\n", .{returns});
2494                    while (index < returns) : (index += 1) {
2495                        _ = try parseDumpType(step, std.wasm.Valtype, &reader, writer);
2496                    }
2497                }
2498            },
2499            .import => {
2500                var i: u32 = 0;
2501                while (i < entries) : (i += 1) {
2502                    const module_name_len = try reader.takeLeb128(u32);
2503                    const module_name = data[reader.seek..][0..module_name_len];
2504                    reader.seek += module_name_len;
2505                    const name_len = try reader.takeLeb128(u32);
2506                    const name = data[reader.seek..][0..name_len];
2507                    reader.seek += name_len;
2508
2509                    const kind = std.enums.fromInt(std.wasm.ExternalKind, try reader.takeByte()) orelse {
2510                        return step.fail("invalid import kind", .{});
2511                    };
2512
2513                    try writer.print(
2514                        \\module {s}
2515                        \\name {s}
2516                        \\kind {s}
2517                    , .{ module_name, name, @tagName(kind) });
2518                    try writer.writeByte('\n');
2519                    switch (kind) {
2520                        .function => {
2521                            try writer.print("index {d}\n", .{try reader.takeLeb128(u32)});
2522                        },
2523                        .memory => {
2524                            try parseDumpLimits(&reader, writer);
2525                        },
2526                        .global => {
2527                            _ = try parseDumpType(step, std.wasm.Valtype, &reader, writer);
2528                            try writer.print("mutable {}\n", .{0x01 == try reader.takeLeb128(u32)});
2529                        },
2530                        .table => {
2531                            _ = try parseDumpType(step, std.wasm.RefType, &reader, writer);
2532                            try parseDumpLimits(&reader, writer);
2533                        },
2534                    }
2535                }
2536            },
2537            .function => {
2538                var i: u32 = 0;
2539                while (i < entries) : (i += 1) {
2540                    try writer.print("index {d}\n", .{try reader.takeLeb128(u32)});
2541                }
2542            },
2543            .table => {
2544                var i: u32 = 0;
2545                while (i < entries) : (i += 1) {
2546                    _ = try parseDumpType(step, std.wasm.RefType, &reader, writer);
2547                    try parseDumpLimits(&reader, writer);
2548                }
2549            },
2550            .memory => {
2551                var i: u32 = 0;
2552                while (i < entries) : (i += 1) {
2553                    try parseDumpLimits(&reader, writer);
2554                }
2555            },
2556            .global => {
2557                var i: u32 = 0;
2558                while (i < entries) : (i += 1) {
2559                    _ = try parseDumpType(step, std.wasm.Valtype, &reader, writer);
2560                    try writer.print("mutable {}\n", .{0x01 == try reader.takeLeb128(u1)});
2561                    try parseDumpInit(step, &reader, writer);
2562                }
2563            },
2564            .@"export" => {
2565                var i: u32 = 0;
2566                while (i < entries) : (i += 1) {
2567                    const name_len = try reader.takeLeb128(u32);
2568                    const name = data[reader.seek..][0..name_len];
2569                    reader.seek += name_len;
2570                    const kind_byte = try reader.takeLeb128(u8);
2571                    const kind = std.enums.fromInt(std.wasm.ExternalKind, kind_byte) orelse {
2572                        return step.fail("invalid export kind value '{d}'", .{kind_byte});
2573                    };
2574                    const index = try reader.takeLeb128(u32);
2575                    try writer.print(
2576                        \\name {s}
2577                        \\kind {s}
2578                        \\index {d}
2579                    , .{ name, @tagName(kind), index });
2580                    try writer.writeByte('\n');
2581                }
2582            },
2583            .element => {
2584                var i: u32 = 0;
2585                while (i < entries) : (i += 1) {
2586                    try writer.print("table index {d}\n", .{try reader.takeLeb128(u32)});
2587                    try parseDumpInit(step, &reader, writer);
2588
2589                    const function_indexes = try reader.takeLeb128(u32);
2590                    var function_index: u32 = 0;
2591                    try writer.print("indexes {d}\n", .{function_indexes});
2592                    while (function_index < function_indexes) : (function_index += 1) {
2593                        try writer.print("index {d}\n", .{try reader.takeLeb128(u32)});
2594                    }
2595                }
2596            },
2597            .code => {}, // code section is considered opaque to linker
2598            .data => {
2599                var i: u32 = 0;
2600                while (i < entries) : (i += 1) {
2601                    const flags = try reader.takeLeb128(u32);
2602                    const index = if (flags & 0x02 != 0)
2603                        try reader.takeLeb128(u32)
2604                    else
2605                        0;
2606                    try writer.print("memory index 0x{x}\n", .{index});
2607                    if (flags == 0) {
2608                        try parseDumpInit(step, &reader, writer);
2609                    }
2610
2611                    const size = try reader.takeLeb128(u32);
2612                    try writer.print("size {d}\n", .{size});
2613                    try reader.discardAll(size); // we do not care about the content of the segments
2614                }
2615            },
2616            else => unreachable,
2617        }
2618    }
2619
2620    fn parseDumpType(step: *Step, comptime E: type, reader: *std.Io.Reader, writer: *std.Io.Writer) !E {
2621        const byte = try reader.takeByte();
2622        const tag = std.enums.fromInt(E, byte) orelse {
2623            return step.fail("invalid wasm type value '{d}'", .{byte});
2624        };
2625        try writer.print("type {s}\n", .{@tagName(tag)});
2626        return tag;
2627    }
2628
2629    fn parseDumpLimits(reader: anytype, writer: anytype) !void {
2630        const flags = try reader.takeLeb128(u8);
2631        const min = try reader.takeLeb128(u32);
2632
2633        try writer.print("min {x}\n", .{min});
2634        if (flags != 0) {
2635            try writer.print("max {x}\n", .{try reader.takeLeb128(u32)});
2636        }
2637    }
2638
2639    fn parseDumpInit(step: *Step, reader: *std.Io.Reader, writer: *std.Io.Writer) !void {
2640        const byte = try reader.takeByte();
2641        const opcode = std.enums.fromInt(std.wasm.Opcode, byte) orelse {
2642            return step.fail("invalid wasm opcode '{d}'", .{byte});
2643        };
2644        switch (opcode) {
2645            .i32_const => try writer.print("i32.const {x}\n", .{try reader.takeLeb128(i32)}),
2646            .i64_const => try writer.print("i64.const {x}\n", .{try reader.takeLeb128(i64)}),
2647            .f32_const => try writer.print("f32.const {x}\n", .{@as(f32, @bitCast(try reader.takeInt(u32, .little)))}),
2648            .f64_const => try writer.print("f64.const {x}\n", .{@as(f64, @bitCast(try reader.takeInt(u64, .little)))}),
2649            .global_get => try writer.print("global.get {x}\n", .{try reader.takeLeb128(u32)}),
2650            else => unreachable,
2651        }
2652        const end_opcode = try reader.takeLeb128(u8);
2653        if (end_opcode != @intFromEnum(std.wasm.Opcode.end)) {
2654            return step.fail("expected 'end' opcode in init expression", .{});
2655        }
2656    }
2657
2658    /// https://webassembly.github.io/spec/core/appendix/custom.html
2659    fn parseDumpNames(step: *Step, reader: *std.Io.Reader, writer: *std.Io.Writer, data: []const u8) !void {
2660        while (reader.seek < data.len) {
2661            switch (try parseDumpType(step, std.wasm.NameSubsection, reader, writer)) {
2662                // The module name subsection ... consists of a single name
2663                // that is assigned to the module itself.
2664                .module => {
2665                    const size = try reader.takeLeb128(u32);
2666                    const name_len = try reader.takeLeb128(u32);
2667                    if (size != name_len + 1) return error.BadSubsectionSize;
2668                    if (reader.seek + name_len > data.len) return error.UnexpectedEndOfStream;
2669                    try writer.print("name {s}\n", .{data[reader.seek..][0..name_len]});
2670                    reader.seek += name_len;
2671                },
2672
2673                // The function name subsection ... consists of a name map
2674                // assigning function names to function indices.
2675                .function, .global, .data_segment => {
2676                    const size = try reader.takeLeb128(u32);
2677                    const entries = try reader.takeLeb128(u32);
2678                    try writer.print(
2679                        \\size {d}
2680                        \\names {d}
2681                        \\
2682                    , .{ size, entries });
2683                    for (0..entries) |_| {
2684                        const index = try reader.takeLeb128(u32);
2685                        const name_len = try reader.takeLeb128(u32);
2686                        if (reader.seek + name_len > data.len) return error.UnexpectedEndOfStream;
2687                        const name = data[reader.seek..][0..name_len];
2688                        reader.seek += name.len;
2689
2690                        try writer.print(
2691                            \\index {d}
2692                            \\name {s}
2693                            \\
2694                        , .{ index, name });
2695                    }
2696                },
2697
2698                // The local name subsection ... consists of an indirect name
2699                // map assigning local names to local indices grouped by
2700                // function indices.
2701                .local => {
2702                    return step.fail("TODO implement parseDumpNames for local subsections", .{});
2703                },
2704
2705                else => |t| return step.fail("invalid subsection type: {s}", .{@tagName(t)}),
2706            }
2707        }
2708    }
2709
2710    fn parseDumpProducers(reader: *std.Io.Reader, writer: *std.Io.Writer, data: []const u8) !void {
2711        const field_count = try reader.takeLeb128(u32);
2712        try writer.print("fields {d}\n", .{field_count});
2713        var current_field: u32 = 0;
2714        while (current_field < field_count) : (current_field += 1) {
2715            const field_name_length = try reader.takeLeb128(u32);
2716            const field_name = data[reader.seek..][0..field_name_length];
2717            reader.seek += field_name_length;
2718
2719            const value_count = try reader.takeLeb128(u32);
2720            try writer.print(
2721                \\field_name {s}
2722                \\values {d}
2723            , .{ field_name, value_count });
2724            try writer.writeByte('\n');
2725            var current_value: u32 = 0;
2726            while (current_value < value_count) : (current_value += 1) {
2727                const value_length = try reader.takeLeb128(u32);
2728                const value = data[reader.seek..][0..value_length];
2729                reader.seek += value_length;
2730
2731                const version_length = try reader.takeLeb128(u32);
2732                const version = data[reader.seek..][0..version_length];
2733                reader.seek += version_length;
2734
2735                try writer.print(
2736                    \\value_name {s}
2737                    \\version {s}
2738                , .{ value, version });
2739                try writer.writeByte('\n');
2740            }
2741        }
2742    }
2743
2744    fn parseDumpFeatures(reader: *std.Io.Reader, writer: *std.Io.Writer, data: []const u8) !void {
2745        const feature_count = try reader.takeLeb128(u32);
2746        try writer.print("features {d}\n", .{feature_count});
2747
2748        var index: u32 = 0;
2749        while (index < feature_count) : (index += 1) {
2750            const prefix_byte = try reader.takeLeb128(u8);
2751            const name_length = try reader.takeLeb128(u32);
2752            const feature_name = data[reader.seek..][0..name_length];
2753            reader.seek += name_length;
2754
2755            try writer.print("{c} {s}\n", .{ prefix_byte, feature_name });
2756        }
2757    }
2758};