forked from OSchip/llvm-project
757 lines
24 KiB
C++
757 lines
24 KiB
C++
//===- Symbols.cpp --------------------------------------------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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#include "Symbols.h"
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#include "InputFiles.h"
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#include "InputSection.h"
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#include "OutputSections.h"
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#include "SyntheticSections.h"
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#include "Target.h"
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#include "Writer.h"
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#include "lld/Common/ErrorHandler.h"
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#include "lld/Common/Strings.h"
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#include "llvm/ADT/STLExtras.h"
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#include "llvm/Support/FileSystem.h"
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#include "llvm/Support/Path.h"
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#include <cstring>
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using namespace llvm;
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using namespace llvm::object;
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using namespace llvm::ELF;
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using namespace lld;
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using namespace lld::elf;
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// Returns a symbol for an error message.
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static std::string demangle(StringRef symName) {
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if (elf::config->demangle)
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return demangleItanium(symName);
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return std::string(symName);
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}
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std::string lld::toString(const elf::Symbol &sym) {
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StringRef name = sym.getName();
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std::string ret = demangle(name);
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const char *suffix = sym.getVersionSuffix();
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if (*suffix == '@')
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ret += suffix;
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return ret;
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}
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std::string lld::toELFString(const Archive::Symbol &b) {
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return demangle(b.getName());
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}
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Defined *ElfSym::bss;
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Defined *ElfSym::etext1;
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Defined *ElfSym::etext2;
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Defined *ElfSym::edata1;
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Defined *ElfSym::edata2;
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Defined *ElfSym::end1;
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Defined *ElfSym::end2;
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Defined *ElfSym::globalOffsetTable;
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Defined *ElfSym::mipsGp;
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Defined *ElfSym::mipsGpDisp;
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Defined *ElfSym::mipsLocalGp;
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Defined *ElfSym::relaIpltStart;
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Defined *ElfSym::relaIpltEnd;
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Defined *ElfSym::riscvGlobalPointer;
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Defined *ElfSym::tlsModuleBase;
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DenseMap<const Symbol *, std::pair<const InputFile *, const InputFile *>>
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elf::backwardReferences;
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static uint64_t getSymVA(const Symbol &sym, int64_t &addend) {
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switch (sym.kind()) {
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case Symbol::DefinedKind: {
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auto &d = cast<Defined>(sym);
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SectionBase *isec = d.section;
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// This is an absolute symbol.
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if (!isec)
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return d.value;
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assert(isec != &InputSection::discarded);
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isec = isec->repl;
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uint64_t offset = d.value;
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// An object in an SHF_MERGE section might be referenced via a
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// section symbol (as a hack for reducing the number of local
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// symbols).
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// Depending on the addend, the reference via a section symbol
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// refers to a different object in the merge section.
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// Since the objects in the merge section are not necessarily
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// contiguous in the output, the addend can thus affect the final
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// VA in a non-linear way.
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// To make this work, we incorporate the addend into the section
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// offset (and zero out the addend for later processing) so that
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// we find the right object in the section.
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if (d.isSection()) {
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offset += addend;
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addend = 0;
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}
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// In the typical case, this is actually very simple and boils
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// down to adding together 3 numbers:
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// 1. The address of the output section.
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// 2. The offset of the input section within the output section.
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// 3. The offset within the input section (this addition happens
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// inside InputSection::getOffset).
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//
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// If you understand the data structures involved with this next
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// line (and how they get built), then you have a pretty good
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// understanding of the linker.
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uint64_t va = isec->getVA(offset);
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// MIPS relocatable files can mix regular and microMIPS code.
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// Linker needs to distinguish such code. To do so microMIPS
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// symbols has the `STO_MIPS_MICROMIPS` flag in the `st_other`
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// field. Unfortunately, the `MIPS::relocate()` method has
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// a symbol value only. To pass type of the symbol (regular/microMIPS)
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// to that routine as well as other places where we write
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// a symbol value as-is (.dynamic section, `Elf_Ehdr::e_entry`
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// field etc) do the same trick as compiler uses to mark microMIPS
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// for CPU - set the less-significant bit.
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if (config->emachine == EM_MIPS && isMicroMips() &&
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((sym.stOther & STO_MIPS_MICROMIPS) || sym.needsPltAddr))
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va |= 1;
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if (d.isTls() && !config->relocatable) {
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// Use the address of the TLS segment's first section rather than the
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// segment's address, because segment addresses aren't initialized until
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// after sections are finalized. (e.g. Measuring the size of .rela.dyn
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// for Android relocation packing requires knowing TLS symbol addresses
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// during section finalization.)
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if (!Out::tlsPhdr || !Out::tlsPhdr->firstSec)
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fatal(toString(d.file) +
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" has an STT_TLS symbol but doesn't have an SHF_TLS section");
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return va - Out::tlsPhdr->firstSec->addr;
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}
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return va;
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}
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case Symbol::SharedKind:
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case Symbol::UndefinedKind:
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return 0;
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case Symbol::LazyArchiveKind:
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case Symbol::LazyObjectKind:
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assert(sym.isUsedInRegularObj && "lazy symbol reached writer");
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return 0;
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case Symbol::CommonKind:
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llvm_unreachable("common symbol reached writer");
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case Symbol::PlaceholderKind:
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llvm_unreachable("placeholder symbol reached writer");
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}
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llvm_unreachable("invalid symbol kind");
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}
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uint64_t Symbol::getVA(int64_t addend) const {
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uint64_t outVA = getSymVA(*this, addend);
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return outVA + addend;
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}
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uint64_t Symbol::getGotVA() const {
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if (gotInIgot)
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return in.igotPlt->getVA() + getGotPltOffset();
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return in.got->getVA() + getGotOffset();
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}
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uint64_t Symbol::getGotOffset() const {
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return gotIndex * target->gotEntrySize;
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}
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uint64_t Symbol::getGotPltVA() const {
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if (isInIplt)
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return in.igotPlt->getVA() + getGotPltOffset();
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return in.gotPlt->getVA() + getGotPltOffset();
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}
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uint64_t Symbol::getGotPltOffset() const {
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if (isInIplt)
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return pltIndex * target->gotEntrySize;
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return (pltIndex + target->gotPltHeaderEntriesNum) * target->gotEntrySize;
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}
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uint64_t Symbol::getPltVA() const {
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uint64_t outVA = isInIplt
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? in.iplt->getVA() + pltIndex * target->ipltEntrySize
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: in.plt->getVA() + in.plt->headerSize +
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pltIndex * target->pltEntrySize;
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// While linking microMIPS code PLT code are always microMIPS
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// code. Set the less-significant bit to track that fact.
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// See detailed comment in the `getSymVA` function.
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if (config->emachine == EM_MIPS && isMicroMips())
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outVA |= 1;
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return outVA;
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}
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uint64_t Symbol::getSize() const {
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if (const auto *dr = dyn_cast<Defined>(this))
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return dr->size;
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return cast<SharedSymbol>(this)->size;
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}
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OutputSection *Symbol::getOutputSection() const {
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if (auto *s = dyn_cast<Defined>(this)) {
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if (auto *sec = s->section)
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return sec->repl->getOutputSection();
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return nullptr;
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}
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return nullptr;
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}
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// If a symbol name contains '@', the characters after that is
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// a symbol version name. This function parses that.
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void Symbol::parseSymbolVersion() {
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StringRef s = getName();
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size_t pos = s.find('@');
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if (pos == 0 || pos == StringRef::npos)
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return;
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StringRef verstr = s.substr(pos + 1);
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if (verstr.empty())
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return;
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// Truncate the symbol name so that it doesn't include the version string.
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nameSize = pos;
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// If this is not in this DSO, it is not a definition.
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if (!isDefined())
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return;
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// '@@' in a symbol name means the default version.
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// It is usually the most recent one.
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bool isDefault = (verstr[0] == '@');
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if (isDefault)
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verstr = verstr.substr(1);
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for (const VersionDefinition &ver : namedVersionDefs()) {
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if (ver.name != verstr)
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continue;
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if (isDefault)
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versionId = ver.id;
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else
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versionId = ver.id | VERSYM_HIDDEN;
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return;
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}
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// It is an error if the specified version is not defined.
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// Usually version script is not provided when linking executable,
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// but we may still want to override a versioned symbol from DSO,
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// so we do not report error in this case. We also do not error
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// if the symbol has a local version as it won't be in the dynamic
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// symbol table.
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if (config->shared && versionId != VER_NDX_LOCAL)
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error(toString(file) + ": symbol " + s + " has undefined version " +
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verstr);
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}
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void Symbol::fetch() const {
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if (auto *sym = dyn_cast<LazyArchive>(this)) {
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cast<ArchiveFile>(sym->file)->fetch(sym->sym);
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return;
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}
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if (auto *sym = dyn_cast<LazyObject>(this)) {
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dyn_cast<LazyObjFile>(sym->file)->fetch();
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return;
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}
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llvm_unreachable("Symbol::fetch() is called on a non-lazy symbol");
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}
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MemoryBufferRef LazyArchive::getMemberBuffer() {
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Archive::Child c =
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CHECK(sym.getMember(),
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"could not get the member for symbol " + toELFString(sym));
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return CHECK(c.getMemoryBufferRef(),
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"could not get the buffer for the member defining symbol " +
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toELFString(sym));
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}
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uint8_t Symbol::computeBinding() const {
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if (config->relocatable)
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return binding;
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if ((visibility != STV_DEFAULT && visibility != STV_PROTECTED) ||
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(versionId == VER_NDX_LOCAL && isDefined()))
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return STB_LOCAL;
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if (!config->gnuUnique && binding == STB_GNU_UNIQUE)
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return STB_GLOBAL;
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return binding;
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}
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bool Symbol::includeInDynsym() const {
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if (!config->hasDynSymTab)
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return false;
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if (computeBinding() == STB_LOCAL)
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return false;
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if (!isDefined() && !isCommon())
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// This should unconditionally return true, unfortunately glibc -static-pie
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// expects undefined weak symbols not to exist in .dynsym, e.g.
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// __pthread_mutex_lock reference in _dl_add_to_namespace_list,
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// __pthread_initialize_minimal reference in csu/libc-start.c.
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return !(config->noDynamicLinker && isUndefWeak());
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return exportDynamic || inDynamicList;
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}
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// Print out a log message for --trace-symbol.
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void elf::printTraceSymbol(const Symbol *sym) {
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std::string s;
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if (sym->isUndefined())
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s = ": reference to ";
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else if (sym->isLazy())
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s = ": lazy definition of ";
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else if (sym->isShared())
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s = ": shared definition of ";
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else if (sym->isCommon())
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s = ": common definition of ";
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else
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s = ": definition of ";
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message(toString(sym->file) + s + sym->getName());
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}
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void elf::maybeWarnUnorderableSymbol(const Symbol *sym) {
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if (!config->warnSymbolOrdering)
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return;
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// If UnresolvedPolicy::Ignore is used, no "undefined symbol" error/warning
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// is emitted. It makes sense to not warn on undefined symbols.
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//
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// Note, ld.bfd --symbol-ordering-file= does not warn on undefined symbols,
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// but we don't have to be compatible here.
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if (sym->isUndefined() &&
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config->unresolvedSymbols == UnresolvedPolicy::Ignore)
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return;
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const InputFile *file = sym->file;
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auto *d = dyn_cast<Defined>(sym);
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auto report = [&](StringRef s) { warn(toString(file) + s + sym->getName()); };
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if (sym->isUndefined())
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report(": unable to order undefined symbol: ");
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else if (sym->isShared())
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report(": unable to order shared symbol: ");
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else if (d && !d->section)
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report(": unable to order absolute symbol: ");
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else if (d && isa<OutputSection>(d->section))
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report(": unable to order synthetic symbol: ");
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else if (d && !d->section->repl->isLive())
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report(": unable to order discarded symbol: ");
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}
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// Returns true if a symbol can be replaced at load-time by a symbol
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// with the same name defined in other ELF executable or DSO.
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bool elf::computeIsPreemptible(const Symbol &sym) {
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assert(!sym.isLocal());
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// Only symbols with default visibility that appear in dynsym can be
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// preempted. Symbols with protected visibility cannot be preempted.
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if (!sym.includeInDynsym() || sym.visibility != STV_DEFAULT)
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return false;
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// At this point copy relocations have not been created yet, so any
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// symbol that is not defined locally is preemptible.
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if (!sym.isDefined())
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return true;
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if (!config->shared)
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return false;
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// If -Bsymbolic or --dynamic-list is specified, or -Bsymbolic-functions is
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// specified and the symbol is STT_FUNC, the symbol is preemptible iff it is
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// in the dynamic list.
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if (config->symbolic || (config->bsymbolicFunctions && sym.isFunc()))
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return sym.inDynamicList;
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return true;
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}
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void elf::reportBackrefs() {
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for (auto &it : backwardReferences) {
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const Symbol &sym = *it.first;
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std::string to = toString(it.second.second);
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// Some libraries have known problems and can cause noise. Filter them out
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// with --warn-backrefs-exclude=. to may look like *.o or *.a(*.o).
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bool exclude = false;
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for (const llvm::GlobPattern &pat : config->warnBackrefsExclude)
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if (pat.match(to)) {
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exclude = true;
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break;
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}
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if (!exclude)
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warn("backward reference detected: " + sym.getName() + " in " +
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toString(it.second.first) + " refers to " + to);
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}
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}
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static uint8_t getMinVisibility(uint8_t va, uint8_t vb) {
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if (va == STV_DEFAULT)
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return vb;
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if (vb == STV_DEFAULT)
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return va;
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return std::min(va, vb);
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}
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// Merge symbol properties.
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//
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// When we have many symbols of the same name, we choose one of them,
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// and that's the result of symbol resolution. However, symbols that
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// were not chosen still affect some symbol properties.
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void Symbol::mergeProperties(const Symbol &other) {
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if (other.exportDynamic)
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exportDynamic = true;
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if (other.isUsedInRegularObj)
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isUsedInRegularObj = true;
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// DSO symbols do not affect visibility in the output.
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if (!other.isShared())
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visibility = getMinVisibility(visibility, other.visibility);
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}
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void Symbol::resolve(const Symbol &other) {
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mergeProperties(other);
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if (isPlaceholder()) {
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replace(other);
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return;
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}
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switch (other.kind()) {
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case Symbol::UndefinedKind:
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resolveUndefined(cast<Undefined>(other));
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break;
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case Symbol::CommonKind:
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resolveCommon(cast<CommonSymbol>(other));
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break;
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case Symbol::DefinedKind:
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resolveDefined(cast<Defined>(other));
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break;
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case Symbol::LazyArchiveKind:
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resolveLazy(cast<LazyArchive>(other));
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break;
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case Symbol::LazyObjectKind:
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resolveLazy(cast<LazyObject>(other));
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break;
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case Symbol::SharedKind:
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resolveShared(cast<SharedSymbol>(other));
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break;
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case Symbol::PlaceholderKind:
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llvm_unreachable("bad symbol kind");
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}
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}
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void Symbol::resolveUndefined(const Undefined &other) {
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// An undefined symbol with non default visibility must be satisfied
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// in the same DSO.
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//
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// If this is a non-weak defined symbol in a discarded section, override the
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// existing undefined symbol for better error message later.
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if ((isShared() && other.visibility != STV_DEFAULT) ||
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(isUndefined() && other.binding != STB_WEAK && other.discardedSecIdx)) {
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replace(other);
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return;
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}
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if (traced)
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printTraceSymbol(&other);
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if (isLazy()) {
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// An undefined weak will not fetch archive members. See comment on Lazy in
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// Symbols.h for the details.
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if (other.binding == STB_WEAK) {
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binding = STB_WEAK;
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type = other.type;
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return;
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}
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// Do extra check for --warn-backrefs.
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//
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// --warn-backrefs is an option to prevent an undefined reference from
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// fetching an archive member written earlier in the command line. It can be
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// used to keep compatibility with GNU linkers to some degree.
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// I'll explain the feature and why you may find it useful in this comment.
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//
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// lld's symbol resolution semantics is more relaxed than traditional Unix
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// linkers. For example,
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//
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// ld.lld foo.a bar.o
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//
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// succeeds even if bar.o contains an undefined symbol that has to be
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// resolved by some object file in foo.a. Traditional Unix linkers don't
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// allow this kind of backward reference, as they visit each file only once
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// from left to right in the command line while resolving all undefined
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// symbols at the moment of visiting.
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//
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// In the above case, since there's no undefined symbol when a linker visits
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// foo.a, no files are pulled out from foo.a, and because the linker forgets
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// about foo.a after visiting, it can't resolve undefined symbols in bar.o
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// that could have been resolved otherwise.
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//
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// That lld accepts more relaxed form means that (besides it'd make more
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// sense) you can accidentally write a command line or a build file that
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// works only with lld, even if you have a plan to distribute it to wider
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// users who may be using GNU linkers. With --warn-backrefs, you can detect
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// a library order that doesn't work with other Unix linkers.
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//
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// The option is also useful to detect cyclic dependencies between static
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|
// archives. Again, lld accepts
|
|
//
|
|
// ld.lld foo.a bar.a
|
|
//
|
|
// even if foo.a and bar.a depend on each other. With --warn-backrefs, it is
|
|
// handled as an error.
|
|
//
|
|
// Here is how the option works. We assign a group ID to each file. A file
|
|
// with a smaller group ID can pull out object files from an archive file
|
|
// with an equal or greater group ID. Otherwise, it is a reverse dependency
|
|
// and an error.
|
|
//
|
|
// A file outside --{start,end}-group gets a fresh ID when instantiated. All
|
|
// files within the same --{start,end}-group get the same group ID. E.g.
|
|
//
|
|
// ld.lld A B --start-group C D --end-group E
|
|
//
|
|
// A forms group 0. B form group 1. C and D (including their member object
|
|
// files) form group 2. E forms group 3. I think that you can see how this
|
|
// group assignment rule simulates the traditional linker's semantics.
|
|
bool backref = config->warnBackrefs && other.file &&
|
|
file->groupId < other.file->groupId;
|
|
fetch();
|
|
|
|
// We don't report backward references to weak symbols as they can be
|
|
// overridden later.
|
|
//
|
|
// A traditional linker does not error for -ldef1 -lref -ldef2 (linking
|
|
// sandwich), where def2 may or may not be the same as def1. We don't want
|
|
// to warn for this case, so dismiss the warning if we see a subsequent lazy
|
|
// definition. this->file needs to be saved because in the case of LTO it
|
|
// may be reset to nullptr or be replaced with a file named lto.tmp.
|
|
if (backref && !isWeak())
|
|
backwardReferences.try_emplace(this, std::make_pair(other.file, file));
|
|
return;
|
|
}
|
|
|
|
// Undefined symbols in a SharedFile do not change the binding.
|
|
if (dyn_cast_or_null<SharedFile>(other.file))
|
|
return;
|
|
|
|
if (isUndefined() || isShared()) {
|
|
// The binding will be weak if there is at least one reference and all are
|
|
// weak. The binding has one opportunity to change to weak: if the first
|
|
// reference is weak.
|
|
if (other.binding != STB_WEAK || !referenced)
|
|
binding = other.binding;
|
|
}
|
|
}
|
|
|
|
// Using .symver foo,foo@@VER unfortunately creates two symbols: foo and
|
|
// foo@@VER. We want to effectively ignore foo, so give precedence to
|
|
// foo@@VER.
|
|
// FIXME: If users can transition to using
|
|
// .symver foo,foo@@@VER
|
|
// we can delete this hack.
|
|
static int compareVersion(StringRef a, StringRef b) {
|
|
bool x = a.contains("@@");
|
|
bool y = b.contains("@@");
|
|
if (!x && y)
|
|
return 1;
|
|
if (x && !y)
|
|
return -1;
|
|
return 0;
|
|
}
|
|
|
|
// Compare two symbols. Return 1 if the new symbol should win, -1 if
|
|
// the new symbol should lose, or 0 if there is a conflict.
|
|
int Symbol::compare(const Symbol *other) const {
|
|
assert(other->isDefined() || other->isCommon());
|
|
|
|
if (!isDefined() && !isCommon())
|
|
return 1;
|
|
|
|
if (int cmp = compareVersion(getName(), other->getName()))
|
|
return cmp;
|
|
|
|
if (other->isWeak())
|
|
return -1;
|
|
|
|
if (isWeak())
|
|
return 1;
|
|
|
|
if (isCommon() && other->isCommon()) {
|
|
if (config->warnCommon)
|
|
warn("multiple common of " + getName());
|
|
return 0;
|
|
}
|
|
|
|
if (isCommon()) {
|
|
if (config->warnCommon)
|
|
warn("common " + getName() + " is overridden");
|
|
return 1;
|
|
}
|
|
|
|
if (other->isCommon()) {
|
|
if (config->warnCommon)
|
|
warn("common " + getName() + " is overridden");
|
|
return -1;
|
|
}
|
|
|
|
auto *oldSym = cast<Defined>(this);
|
|
auto *newSym = cast<Defined>(other);
|
|
|
|
if (dyn_cast_or_null<BitcodeFile>(other->file))
|
|
return 0;
|
|
|
|
if (!oldSym->section && !newSym->section && oldSym->value == newSym->value &&
|
|
newSym->binding == STB_GLOBAL)
|
|
return -1;
|
|
|
|
return 0;
|
|
}
|
|
|
|
static void reportDuplicate(Symbol *sym, InputFile *newFile,
|
|
InputSectionBase *errSec, uint64_t errOffset) {
|
|
if (config->allowMultipleDefinition)
|
|
return;
|
|
|
|
Defined *d = cast<Defined>(sym);
|
|
if (!d->section || !errSec) {
|
|
error("duplicate symbol: " + toString(*sym) + "\n>>> defined in " +
|
|
toString(sym->file) + "\n>>> defined in " + toString(newFile));
|
|
return;
|
|
}
|
|
|
|
// Construct and print an error message in the form of:
|
|
//
|
|
// ld.lld: error: duplicate symbol: foo
|
|
// >>> defined at bar.c:30
|
|
// >>> bar.o (/home/alice/src/bar.o)
|
|
// >>> defined at baz.c:563
|
|
// >>> baz.o in archive libbaz.a
|
|
auto *sec1 = cast<InputSectionBase>(d->section);
|
|
std::string src1 = sec1->getSrcMsg(*sym, d->value);
|
|
std::string obj1 = sec1->getObjMsg(d->value);
|
|
std::string src2 = errSec->getSrcMsg(*sym, errOffset);
|
|
std::string obj2 = errSec->getObjMsg(errOffset);
|
|
|
|
std::string msg = "duplicate symbol: " + toString(*sym) + "\n>>> defined at ";
|
|
if (!src1.empty())
|
|
msg += src1 + "\n>>> ";
|
|
msg += obj1 + "\n>>> defined at ";
|
|
if (!src2.empty())
|
|
msg += src2 + "\n>>> ";
|
|
msg += obj2;
|
|
error(msg);
|
|
}
|
|
|
|
void Symbol::resolveCommon(const CommonSymbol &other) {
|
|
int cmp = compare(&other);
|
|
if (cmp < 0)
|
|
return;
|
|
|
|
if (cmp > 0) {
|
|
if (auto *s = dyn_cast<SharedSymbol>(this)) {
|
|
// Increase st_size if the shared symbol has a larger st_size. The shared
|
|
// symbol may be created from common symbols. The fact that some object
|
|
// files were linked into a shared object first should not change the
|
|
// regular rule that picks the largest st_size.
|
|
uint64_t size = s->size;
|
|
replace(other);
|
|
if (size > cast<CommonSymbol>(this)->size)
|
|
cast<CommonSymbol>(this)->size = size;
|
|
} else {
|
|
replace(other);
|
|
}
|
|
return;
|
|
}
|
|
|
|
CommonSymbol *oldSym = cast<CommonSymbol>(this);
|
|
|
|
oldSym->alignment = std::max(oldSym->alignment, other.alignment);
|
|
if (oldSym->size < other.size) {
|
|
oldSym->file = other.file;
|
|
oldSym->size = other.size;
|
|
}
|
|
}
|
|
|
|
void Symbol::resolveDefined(const Defined &other) {
|
|
int cmp = compare(&other);
|
|
if (cmp > 0)
|
|
replace(other);
|
|
else if (cmp == 0)
|
|
reportDuplicate(this, other.file,
|
|
dyn_cast_or_null<InputSectionBase>(other.section),
|
|
other.value);
|
|
}
|
|
|
|
template <class LazyT>
|
|
static void replaceCommon(Symbol &oldSym, const LazyT &newSym) {
|
|
backwardReferences.erase(&oldSym);
|
|
oldSym.replace(newSym);
|
|
newSym.fetch();
|
|
}
|
|
|
|
template <class LazyT> void Symbol::resolveLazy(const LazyT &other) {
|
|
// For common objects, we want to look for global or weak definitions that
|
|
// should be fetched as the canonical definition instead.
|
|
if (isCommon() && elf::config->fortranCommon) {
|
|
if (auto *laSym = dyn_cast<LazyArchive>(&other)) {
|
|
ArchiveFile *archive = cast<ArchiveFile>(laSym->file);
|
|
const Archive::Symbol &archiveSym = laSym->sym;
|
|
if (archive->shouldFetchForCommon(archiveSym)) {
|
|
replaceCommon(*this, other);
|
|
return;
|
|
}
|
|
} else if (auto *loSym = dyn_cast<LazyObject>(&other)) {
|
|
LazyObjFile *obj = cast<LazyObjFile>(loSym->file);
|
|
if (obj->shouldFetchForCommon(loSym->getName())) {
|
|
replaceCommon(*this, other);
|
|
return;
|
|
}
|
|
}
|
|
}
|
|
|
|
if (!isUndefined()) {
|
|
// See the comment in resolveUndefined().
|
|
if (isDefined())
|
|
backwardReferences.erase(this);
|
|
return;
|
|
}
|
|
|
|
// An undefined weak will not fetch archive members. See comment on Lazy in
|
|
// Symbols.h for the details.
|
|
if (isWeak()) {
|
|
uint8_t ty = type;
|
|
replace(other);
|
|
type = ty;
|
|
binding = STB_WEAK;
|
|
return;
|
|
}
|
|
|
|
other.fetch();
|
|
}
|
|
|
|
void Symbol::resolveShared(const SharedSymbol &other) {
|
|
if (isCommon()) {
|
|
// See the comment in resolveCommon() above.
|
|
if (other.size > cast<CommonSymbol>(this)->size)
|
|
cast<CommonSymbol>(this)->size = other.size;
|
|
return;
|
|
}
|
|
if (visibility == STV_DEFAULT && (isUndefined() || isLazy())) {
|
|
// An undefined symbol with non default visibility must be satisfied
|
|
// in the same DSO.
|
|
uint8_t bind = binding;
|
|
replace(other);
|
|
binding = bind;
|
|
} else if (traced)
|
|
printTraceSymbol(&other);
|
|
}
|