declareSymbol

pub fn declareSymbol(
    elf: *Elf,
    section_kind: Object.Section,
    maybe_name: ?[]const u8,
    linkage: std.builtin.GlobalLinkage,
    @"type": Object.SymbolType,
    offset: u64,
    size: u64,
) ![]const u8

File

Code

pub fn declareSymbol(
    elf: *Elf,
    section_kind: Object.Section,
    maybe_name: ?[]const u8,
    linkage: std.builtin.GlobalLinkage,
    @"type": Object.SymbolType,
    offset: u64,
    size: u64,
) ![]const u8 {
    const section = blk: {
        if (section_kind == .undefined) break :blk null;
        const section_name = sectionString(section_kind);
        break :blk elf.sections.get(section_name);
    };
    const binding: u8 = switch (linkage) {
        .Internal => std.elf.STB_LOCAL,
        .Strong => std.elf.STB_GLOBAL,
        .Weak => std.elf.STB_WEAK,
        .LinkOnce => unreachable,
    };
    const sym_type: u8 = switch (@"type") {
        .func => std.elf.STT_FUNC,
        .variable => std.elf.STT_OBJECT,
        .external => std.elf.STT_NOTYPE,
    };
    const name = if (maybe_name) |some| some else blk: {
        defer elf.unnamed_symbol_mangle += 1;
        break :blk try std.fmt.allocPrint(elf.arena.allocator(), ".L.{d}", .{elf.unnamed_symbol_mangle});
    };

    const gop = if (linkage == .Internal)
        try elf.local_symbols.getOrPut(elf.arena.child_allocator, name)
    else
        try elf.global_symbols.getOrPut(elf.arena.child_allocator, name);

    if (!gop.found_existing) {
        gop.value_ptr.* = try elf.arena.allocator().create(Symbol);
        elf.strtab_len += name.len + 1; // +1 for null byte
    }
    gop.value_ptr.*.* = .{
        .section = section,
        .size = size,
        .offset = offset,
        .info = (binding << 4) + sym_type,
    };
    return name;
}