tiny.tldr.formats.elf.image.symbols

1pub const symbols = @import("symbols.zig");

1const std = @import("std");2const root = @import("../../../root.zig");3const elf = @import("../root.zig");45const Allocator = std.mem.Allocator;6const model = root.model;7const parallel = root.parallel;8const StringTable = elf.string.Table;9const ObjectFile = elf.parser.ObjectFile;10const ObjectLayout = elf.layout.ObjectLayout;11const OutputSection = elf.layout.OutputSection;12const GlobalSymbol = elf.layout.GlobalSymbol;13const SymbolRef = elf.layout.SymbolRef;14const Access = elf.addressing.Access;15const SymbolAddressCache = elf.addressing.Cache;16const SymbolRecord = elf.format.SymbolRecord;1718const ResolvedEntry = struct {19    found: bool = false,20    name: []const u8 = "",21    entry: SymbolRecord = .{},22};2324const EntryFailure = struct {25    found: bool = false,26    ref_index: usize = 0,27    err: model.Error = error.InvalidObject,2829    fn isFound(failure: EntryFailure) bool {30        return failure.found;31    }3233    fn before(left: EntryFailure, right: EntryFailure) bool {34        return left.ref_index < right.ref_index;35    }36};3738const EntryFailures = parallel.FailureSlots(EntryFailure);3940const ParallelEntryContext = struct {41    objects: []const ObjectFile,42    layouts: []const ObjectLayout,43    output_sections: []const OutputSection,44    globals: *const std.StringHashMapUnmanaged(GlobalSymbol),45    global_symbol_refs: []const SymbolRef,46    symbol_addresses: *SymbolAddressCache,47    resolved_entries: []ResolvedEntry,48    failures: *EntryFailures,49};5051pub const parallel_entry_threshold = 32768;52const entries_per_worker = 8192;5354pub fn appendExecutable(55    allocator: Allocator,56    out: *std.ArrayListUnmanaged(SymbolRecord),57    strtab: *StringTable,58    objects: []const ObjectFile,59    layouts: []const ObjectLayout,60    output_sections: []const OutputSection,61    globals: *const std.StringHashMapUnmanaged(GlobalSymbol),62    global_symbol_refs: []const SymbolRef,63    symbol_addresses: *SymbolAddressCache,64    max_link_jobs: usize,65) model.Error!void {66    const requested_workers = if (max_link_jobs != 0)67        max_link_jobs68    else69        global_symbol_refs.len / entries_per_worker;70    const workers = if (global_symbol_refs.len >= parallel_entry_threshold)71        parallel.chooseWorkers(global_symbol_refs.len, requested_workers)72    else73        1;74    if (workers > 1) {75        return appendExecutableParallel(allocator, out, strtab, objects, layouts, output_sections, globals, global_symbol_refs, symbol_addresses, workers);76    }77    try appendExecutableSerial(allocator, out, strtab, objects, layouts, output_sections, globals, global_symbol_refs, symbol_addresses);78}7980fn appendExecutableSerial(81    allocator: Allocator,82    out: *std.ArrayListUnmanaged(SymbolRecord),83    strtab: *StringTable,84    objects: []const ObjectFile,85    layouts: []const ObjectLayout,86    output_sections: []const OutputSection,87    globals: *const std.StringHashMapUnmanaged(GlobalSymbol),88    global_symbol_refs: []const SymbolRef,89    symbol_addresses: *SymbolAddressCache,90) model.Error!void {91    for (global_symbol_refs) |current_ref| {92        if (try resolveExecutableEntry(.serial, objects, layouts, output_sections, globals, symbol_addresses, current_ref)) |resolved| {93            try appendResolvedEntry(allocator, out, strtab, resolved);94        }95    }96}9798fn appendExecutableParallel(99    allocator: Allocator,100    out: *std.ArrayListUnmanaged(SymbolRecord),101    strtab: *StringTable,102    objects: []const ObjectFile,103    layouts: []const ObjectLayout,104    output_sections: []const OutputSection,105    globals: *const std.StringHashMapUnmanaged(GlobalSymbol),106    global_symbol_refs: []const SymbolRef,107    symbol_addresses: *SymbolAddressCache,108    workers: usize,109) model.Error!void {110    const resolved_entries = try allocator.alloc(ResolvedEntry, global_symbol_refs.len);111    defer allocator.free(resolved_entries);112    for (resolved_entries) |*entry| entry.* = .{};113114    var failures = try EntryFailures.init(allocator, workers, .{});115    defer failures.deinit(allocator);116117    var context = ParallelEntryContext{118        .objects = objects,119        .layouts = layouts,120        .output_sections = output_sections,121        .globals = globals,122        .global_symbol_refs = global_symbol_refs,123        .symbol_addresses = symbol_addresses,124        .resolved_entries = resolved_entries,125        .failures = &failures,126    };127    parallel.forChunks(global_symbol_refs.len, workers, &context, resolveEntryChunk);128    if (failures.earliest(EntryFailure.isFound, EntryFailure.before)) |failure| return failure.err;129130    for (resolved_entries) |resolved| {131        if (!resolved.found) continue;132        try appendResolvedEntry(allocator, out, strtab, resolved);133    }134}135136fn resolveEntryChunk(context: *ParallelEntryContext, worker: usize, start: usize, end: usize) void {137    var index = start;138    while (index < end) : (index += 1) {139        const resolved = resolveExecutableEntry(.concurrent, context.objects, context.layouts, context.output_sections, context.globals, context.symbol_addresses, context.global_symbol_refs[index]) catch |err| {140            const current = context.failures.items[worker];141            const failure = EntryFailure{142                .found = true,143                .ref_index = index,144                .err = err,145            };146            if (!current.found or EntryFailure.before(failure, current)) {147                context.failures.record(worker, failure);148            }149            continue;150        };151        context.resolved_entries[index] = resolved orelse .{};152    }153}154155fn resolveExecutableEntry(156    comptime access: Access,157    objects: []const ObjectFile,158    layouts: []const ObjectLayout,159    output_sections: []const OutputSection,160    globals: *const std.StringHashMapUnmanaged(GlobalSymbol),161    symbol_addresses: *SymbolAddressCache,162    current_ref: SymbolRef,163) model.Error!?ResolvedEntry {164    const object = objects[current_ref.object_index];165    const symbol = object.symbols[current_ref.symbol_index];166    if (elf.section_state.symbolSectionDiscarded(object, symbol)) return null;167    if (elf.addressing.symbolIsTls(object, symbol)) {168        const value = try elf.addressing.tlsOffset(objects, layouts, output_sections, globals, symbol_addresses, current_ref.object_index, current_ref.symbol_index);169        const contribution = try elf.addressing.contribution(objects, layouts, current_ref.object_index, current_ref.symbol_index);170        const output = output_sections[contribution.outputIndex()];171        return .{172            .found = true,173            .name = symbol.name,174            .entry = .{175                .info = symbol.info,176                .other = symbol.other,177                .section_index = output.section_index,178                .value = value,179                .size = symbol.size,180            },181        };182    }183    if (symbol.isAbsolute()) {184        return .{185            .found = true,186            .name = symbol.name,187            .entry = .{188                .info = symbol.info,189                .other = symbol.other,190                .section_index = std.elf.SHN_ABS,191                .value = symbol.value,192                .size = symbol.size,193            },194        };195    }196    const value = try elf.addressing.symbolAddress(access, objects, layouts, output_sections, globals, symbol_addresses, current_ref.object_index, current_ref.symbol_index);197    const contribution = try elf.addressing.contribution(objects, layouts, current_ref.object_index, current_ref.symbol_index);198    const output = output_sections[contribution.outputIndex()];199    return .{200        .found = true,201        .name = symbol.name,202        .entry = .{203            .info = symbol.info,204            .other = symbol.other,205            .section_index = output.section_index,206            .value = value,207            .size = symbol.size,208        },209    };210}211212fn appendResolvedEntry(213    allocator: Allocator,214    out: *std.ArrayListUnmanaged(SymbolRecord),215    strtab: *StringTable,216    resolved: ResolvedEntry,217) model.Error!void {218    var entry = resolved.entry;219    entry.name_offset = try strtab.add(allocator, resolved.name);220    try out.append(allocator, entry);221}