mirror of
https://github.com/rui314/mold.git
synced 2024-12-26 18:02:30 +03:00
245 lines
6.6 KiB
C++
245 lines
6.6 KiB
C++
#include "mold.h"
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using namespace llvm;
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using namespace llvm::ELF;
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InputChunk::InputChunk(Kind kind, ObjectFile *file, const ELF64LE::Shdr &shdr,
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StringRef name)
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: kind(kind), file(file), shdr(shdr), name(name) {
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output_section = OutputSection::get_instance(name, shdr.sh_flags, shdr.sh_type);
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u64 align = (shdr.sh_addralign == 0) ? 1 : shdr.sh_addralign;
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if (align > UINT32_MAX)
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error(toString(file) + ": section sh_addralign is too large");
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if (__builtin_popcount(align) != 1)
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error(toString(file) + ": section sh_addralign is not a power of two");
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}
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void InputSection::copy_to(u8 *buf) {
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if (shdr.sh_type == SHT_NOBITS || shdr.sh_size == 0)
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return;
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// Copy data
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ArrayRef<u8> data = check(file->obj.getSectionContents(shdr));
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memcpy(buf + output_section->shdr.sh_offset + offset, &data[0], data.size());
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// Apply relocations
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u8 *base = buf + output_section->shdr.sh_offset + offset;
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u64 sh_addr = output_section->shdr.sh_addr + offset;
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u64 GOT = out::got->shdr.sh_addr;
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for (int i = 0; i < rels.size(); i++) {
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const ELF64LE::Rela &rel = rels[i];
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StringPieceRef &ref = rel_pieces[i];
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Symbol &sym = *file->symbols[rel.getSymbol(false)];
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u8 *loc = base + rel.r_offset;
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u64 G = sym.got_offset;
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u64 S = ref.piece ? ref.piece->get_addr() : sym.get_addr();
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u64 A = ref.piece ? ref.addend : rel.r_addend;
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u64 P = sh_addr + rel.r_offset;
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u64 L = out::plt->shdr.sh_addr + sym.plt_offset;
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switch (rel.getType(false)) {
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case R_X86_64_NONE:
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break;
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case R_X86_64_64:
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*(u64 *)loc = S + A;
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break;
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case R_X86_64_PC32:
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*(u32 *)loc = S + A - P;
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break;
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case R_X86_64_GOT32:
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*(u64 *)loc = G + A;
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break;
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case R_X86_64_PLT32:
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if (config.is_static && sym.type != STT_GNU_IFUNC)
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*(u32 *)loc = S + A - P; // todo
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else
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*(u32 *)loc = L + A - P;
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break;
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case R_X86_64_GOTPCREL:
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*(u32 *)loc = G + GOT + A - P;
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break;
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case R_X86_64_32:
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case R_X86_64_32S:
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*(u32 *)loc = S + A;
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break;
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case R_X86_64_16:
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*(u16 *)loc = S + A;
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break;
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case R_X86_64_PC16:
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*(u16 *)loc = S + A - P;
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break;
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case R_X86_64_8:
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*loc = S + A;
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break;
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case R_X86_64_PC8:
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*loc = S + A - P;
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break;
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case R_X86_64_TLSGD:
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case R_X86_64_TLSLD:
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case R_X86_64_DTPOFF32:
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// TODO
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break;
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case R_X86_64_GOTTPOFF:
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*(u32 *)loc = sym.gottp_offset + GOT + A - P;
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break;
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case R_X86_64_TPOFF32:
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*(u32 *)loc = S - out::tls_end;
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break;
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case R_X86_64_PC64:
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*(u64 *)loc = S + A - P;
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break;
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case R_X86_64_GOTPC32:
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*(u32 *)loc = GOT + A - P;
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break;
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case R_X86_64_GOTPCRELX:
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case R_X86_64_REX_GOTPCRELX:
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*(u32 *)loc = G + GOT + A - P;
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break;
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default:
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error(toString(this) + ": unknown relocation: " +
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std::to_string(rel.getType(false)));
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}
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}
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static Counter counter("relocs");
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counter.inc(rels.size());
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}
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static bool set_flag(Symbol *sym, u8 bit) {
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u8 flags = sym->flags;
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while (!(flags & bit))
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if (sym->flags.compare_exchange_strong(flags, flags | bit))
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return true;
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return false;
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}
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static bool set_flag2(Symbol *sym, u8 bit) {
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u8 flags = sym->flags2;
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while (!(flags & bit))
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if (sym->flags.compare_exchange_strong(flags, flags | bit))
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return true;
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return false;
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}
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void InputSection::scan_relocations() {
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if (!(shdr.sh_flags & SHF_ALLOC))
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return;
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for (const ELF64LE::Rela &rel : rels) {
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Symbol *sym = file->symbols[rel.getSymbol(false)];
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if (!sym->file || !sym->file->is_alive)
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continue;
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if (sym->file->is_dso && set_flag(sym, Symbol::NEEDS_DYNSYM)) {
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sym->file->num_dynsym++;
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sym->file->dynstr_size += sym->name.size() + 1;
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}
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if (sym->type == STT_GNU_IFUNC && set_flag(sym, Symbol::NEEDS_PLT))
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sym->file->num_plt++;
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switch (rel.getType(false)) {
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case R_X86_64_8:
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case R_X86_64_16:
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case R_X86_64_32:
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case R_X86_64_32S:
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case R_X86_64_64:
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case R_X86_64_PC8:
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case R_X86_64_PC16:
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case R_X86_64_PC32:
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case R_X86_64_PC64:
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sym->flags2 |= Symbol::HAS_ADDR_REL;
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break;
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case R_X86_64_GOT32:
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case R_X86_64_GOTPC32:
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case R_X86_64_GOTPCREL:
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case R_X86_64_GOTPCRELX:
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case R_X86_64_REX_GOTPCRELX:
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sym->flags2 |= Symbol::HAS_GOT_REL;
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break;
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case R_X86_64_PLT32:
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sym->flags2 |= Symbol::HAS_PLT_REL;
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break;
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case R_X86_64_TLSGD:
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sym->flags2 |= Symbol::HAS_TLSGD_REL;
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break;
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case R_X86_64_TLSLD:
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sym->flags2 |= Symbol::HAS_TLSLD_REL;
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break;
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case R_X86_64_DTPOFF32:
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case R_X86_64_GOTTPOFF:
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case R_X86_64_TPOFF32:
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sym->flags2 |= Symbol::HAS_TPOFF_REL;
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break;
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case R_X86_64_NONE:
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break;
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default:
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error(toString(this) + ": unknown relocation: " +
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std::to_string(rel.getType(false)));
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}
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switch (rel.getType(false)) {
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case R_X86_64_GOT32:
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case R_X86_64_GOT64:
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case R_X86_64_GOTOFF64:
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case R_X86_64_GOTPC32:
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case R_X86_64_GOTPC32_TLSDESC:
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case R_X86_64_GOTPC64:
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case R_X86_64_GOTPCREL:
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case R_X86_64_GOTPCRELX:
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case R_X86_64_REX_GOTPCRELX:
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sym->flags2 |= Symbol::HAS_GOT_REL;
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if (set_flag(sym, Symbol::NEEDS_GOT))
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sym->file->num_got++;
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break;
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case R_X86_64_GOTTPOFF:
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sym->flags2 |= Symbol::HAS_GOTTP_REL;
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if (set_flag(sym, Symbol::NEEDS_GOTTP))
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sym->file->num_got++;
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break;
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case R_X86_64_PLT32:
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sym->flags2 |= Symbol::HAS_PLT_REL;
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if (config.is_static)
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break;
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if (set_flag(sym, Symbol::NEEDS_PLT))
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sym->file->num_plt++;
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break;
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default:
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sym->flags2 |= Symbol::HAS_ADDR_REL;
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break;
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}
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}
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}
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MergeableSection::MergeableSection(InputSection *isec, ArrayRef<u8> contents)
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: InputChunk(MERGEABLE, isec->file, isec->shdr, isec->name),
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parent(*MergedSection::get_instance(isec->name, isec->shdr.sh_flags,
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isec->shdr.sh_type)) {
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StringRef data((const char *)&contents[0], contents.size());
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u32 offset = 0;
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while (!data.empty()) {
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size_t end = data.find('\0');
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if (end == StringRef::npos)
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error(toString(this) + ": string is not null terminated");
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StringRef substr = data.substr(0, end + 1);
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data = data.substr(end + 1);
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StringPiece *piece = parent.map.insert(substr, StringPiece(substr));
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pieces.push_back({piece, offset});
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offset += substr.size();
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}
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static Counter counter("string_pieces");
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counter.inc(pieces.size());
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}
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std::string toString(InputChunk *chunk) {
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return (toString(chunk->file) + ":(" + chunk->name + ")").str();
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}
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