tiny.tldr.formats.elf.liveness.symbols

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

1const std = @import("std");2const root = @import("../../../root.zig");3const elf = @import("../root.zig");4const state = @import("state.zig");56const model = root.model;7const GlobalSymbol = elf.layout.GlobalSymbol;8const ObjectFile = elf.parser.ObjectFile;9const SectionRef = elf.parser.SectionRef;10const State = state.State;11const SymbolRef = elf.layout.SymbolRef;12const SyntheticBoundary = elf.addressing.Boundary;13const boundarySectionNameMatches = elf.addressing.boundarySectionNameMatches;14const foldedSection = elf.section_state.foldedSection;15const sectionDiscarded = elf.section_state.sectionDiscarded;16const sectionIsAllocated = elf.format.sectionIsAllocated;17const sectionNameOrEmpty = elf.parser.sectionNameOrEmpty;18const symbolSectionDiscarded = elf.section_state.symbolSectionDiscarded;19const syntheticBoundaryForSymbol = elf.addressing.boundaryForSymbol;2021pub fn mark(22    objects: []const ObjectFile,23    globals: *const std.StringHashMapUnmanaged(GlobalSymbol),24    live: *State,25    symbol_ref: SymbolRef,26    options: model.LinkOptions,27) model.Error!void {28    if (symbol_ref.object_index >= objects.len) return error.InvalidObject;29    const object = objects[symbol_ref.object_index];30    if (symbol_ref.symbol_index >= object.symbols.len) return error.UndefinedSymbol;3132    const symbol = object.symbols[symbol_ref.symbol_index];33    if (symbol.isUndefined()) {34        const global = globals.get(symbol.name) orelse {35            if (symbol.isWeakUndefined()) return;36            const boundary = syntheticBoundaryForSymbol(symbol.name) orelse {37                elf.diagnostic.recordUndefinedSymbol(options, object, symbol);38                return error.UndefinedSymbol;39            };40            if (try markSyntheticBoundarySections(objects, live, boundary)) return;41            if (boundary.optional) return;42            elf.diagnostic.recordUndefinedSymbol(options, object, symbol);43            return error.UndefinedSymbol;44        };45        return mark(objects, globals, live, global.ref, options);46    }47    if (symbolSectionDiscarded(object, symbol) and symbol.name.len != 0) {48        const global = globals.get(symbol.name) orelse return error.MissingSection;49        return mark(objects, globals, live, global.ref, options);50    }51    if (symbol.isCommon()) return;52    if (symbol.isAbsolute()) return;53    if (symbol.section_index >= object.sections.len) return error.UnsupportedRelocation;5455    try state.markSection(56        live,57        objects,58        .{59            .object_index = symbol_ref.object_index,60            .section_index = symbol.section_index,61        },62    );63}6465fn markSyntheticBoundarySections(66    objects: []const ObjectFile,67    live: *State,68    boundary: SyntheticBoundary,69) model.Error!bool {70    var found = false;71    for (objects, 0..) |object, object_index| {72        for (object.sections, 0..) |section, section_index| {73            if (!sectionIsAllocated(section)) continue;74            if (section.size == 0) continue;75            if (sectionDiscarded(object, section_index)) continue;76            if (foldedSection(object, section_index) != null) continue;77            if (!boundarySectionNameMatches(boundary, sectionNameOrEmpty(object, section_index))) continue;78            try state.markSection(79                live,80                objects,81                .{82                    .object_index = object_index,83                    .section_index = section_index,84                },85            );86            found = true;87        }88    }89    return found;90}9192pub fn markRelocationTargets(93    objects: []const ObjectFile,94    globals: *const std.StringHashMapUnmanaged(GlobalSymbol),95    live: *State,96    section_ref: SectionRef,97    options: model.LinkOptions,98) model.Error!void {99    const object = objects[section_ref.object_index];100    for (object.relocationsForSection(section_ref.section_index)) |entry| {101        if (elf.relocation.isNone(entry)) continue;102        if (entry.symbolIndex() >= object.symbols.len) return error.UndefinedSymbol;103        try mark(104            objects,105            globals,106            live,107            .{108                .object_index = section_ref.object_index,109                .symbol_index = @intCast(entry.symbolIndex()),110            },111            options,112        );113    }114}