cde5e5b600
Summary: The COFF linker previously implemented link-time optimization using an API which has now been marked as legacy. This change refactors the COFF linker to use the new LTO API, which is also used by the ELF linker. Reviewers: pcc, ruiu Reviewed By: pcc Subscribers: mgorny, mehdi_amini Differential Revision: https://reviews.llvm.org/D29059 llvm-svn: 293967
84 lines
2.8 KiB
C++
84 lines
2.8 KiB
C++
//===- Symbols.cpp --------------------------------------------------------===//
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//
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// The LLVM Linker
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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#include "Symbols.h"
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#include "Error.h"
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#include "InputFiles.h"
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#include "Memory.h"
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#include "Strings.h"
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#include "llvm/ADT/STLExtras.h"
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#include "llvm/Support/Debug.h"
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#include "llvm/Support/raw_ostream.h"
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using namespace llvm;
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using namespace llvm::object;
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// Returns a symbol name for an error message.
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std::string lld::toString(coff::SymbolBody &B) {
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if (Optional<std::string> S = coff::demangle(B.getName()))
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return ("\"" + *S + "\" (" + B.getName() + ")").str();
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return B.getName();
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}
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namespace lld {
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namespace coff {
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StringRef SymbolBody::getName() {
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// COFF symbol names are read lazily for a performance reason.
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// Non-external symbol names are never used by the linker except for logging
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// or debugging. Their internal references are resolved not by name but by
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// symbol index. And because they are not external, no one can refer them by
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// name. Object files contain lots of non-external symbols, and creating
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// StringRefs for them (which involves lots of strlen() on the string table)
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// is a waste of time.
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if (Name.empty()) {
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auto *D = cast<DefinedCOFF>(this);
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cast<ObjectFile>(D->File)->getCOFFObj()->getSymbolName(D->Sym, Name);
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}
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return Name;
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}
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InputFile *SymbolBody::getFile() {
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if (auto *Sym = dyn_cast<DefinedCOFF>(this))
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return Sym->File;
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if (auto *Sym = dyn_cast<Lazy>(this))
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return Sym->File;
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return nullptr;
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}
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COFFSymbolRef DefinedCOFF::getCOFFSymbol() {
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size_t SymSize =
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cast<ObjectFile>(File)->getCOFFObj()->getSymbolTableEntrySize();
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if (SymSize == sizeof(coff_symbol16))
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return COFFSymbolRef(reinterpret_cast<const coff_symbol16 *>(Sym));
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assert(SymSize == sizeof(coff_symbol32));
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return COFFSymbolRef(reinterpret_cast<const coff_symbol32 *>(Sym));
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}
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DefinedImportThunk::DefinedImportThunk(StringRef Name, DefinedImportData *S,
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uint16_t Machine)
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: Defined(DefinedImportThunkKind, Name) {
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switch (Machine) {
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case AMD64: Data = make<ImportThunkChunkX64>(S); return;
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case I386: Data = make<ImportThunkChunkX86>(S); return;
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case ARMNT: Data = make<ImportThunkChunkARM>(S); return;
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default: llvm_unreachable("unknown machine type");
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}
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}
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Defined *Undefined::getWeakAlias() {
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// A weak alias may be a weak alias to another symbol, so check recursively.
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for (SymbolBody *A = WeakAlias; A; A = cast<Undefined>(A)->WeakAlias)
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if (auto *D = dyn_cast<Defined>(A))
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return D;
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return nullptr;
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}
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} // namespace coff
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} // namespace lld
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