1 //===- Symbols.cpp --------------------------------------------------------===//
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
11 #include "InputFiles.h"
12 #include "lld/Common/ErrorHandler.h"
13 #include "lld/Common/Memory.h"
14 #include "lld/Common/Strings.h"
15 #include "llvm/ADT/STLExtras.h"
16 #include "llvm/Support/Debug.h"
17 #include "llvm/Support/raw_ostream.h"
20 using namespace llvm::object;
22 // Returns a symbol name for an error message.
23 std::string lld::toString(coff::Symbol &B) {
24 if (Optional<std::string> S = lld::demangleMSVC(B.getName()))
25 return ("\"" + *S + "\" (" + B.getName() + ")").str();
32 StringRef Symbol::getName() {
33 // COFF symbol names are read lazily for a performance reason.
34 // Non-external symbol names are never used by the linker except for logging
35 // or debugging. Their internal references are resolved not by name but by
36 // symbol index. And because they are not external, no one can refer them by
37 // name. Object files contain lots of non-external symbols, and creating
38 // StringRefs for them (which involves lots of strlen() on the string table)
39 // is a waste of time.
41 auto *D = cast<DefinedCOFF>(this);
42 cast<ObjFile>(D->File)->getCOFFObj()->getSymbolName(D->Sym, Name);
47 InputFile *Symbol::getFile() {
48 if (auto *Sym = dyn_cast<DefinedCOFF>(this))
50 if (auto *Sym = dyn_cast<Lazy>(this))
55 bool Symbol::isLive() const {
56 if (auto *R = dyn_cast<DefinedRegular>(this))
57 return R->getChunk()->isLive();
58 if (auto *Imp = dyn_cast<DefinedImportData>(this))
59 return Imp->File->Live;
60 if (auto *Imp = dyn_cast<DefinedImportThunk>(this))
61 return Imp->WrappedSym->File->ThunkLive;
62 // Assume any other kind of symbol is live.
66 COFFSymbolRef DefinedCOFF::getCOFFSymbol() {
67 size_t SymSize = cast<ObjFile>(File)->getCOFFObj()->getSymbolTableEntrySize();
68 if (SymSize == sizeof(coff_symbol16))
69 return COFFSymbolRef(reinterpret_cast<const coff_symbol16 *>(Sym));
70 assert(SymSize == sizeof(coff_symbol32));
71 return COFFSymbolRef(reinterpret_cast<const coff_symbol32 *>(Sym));
74 uint16_t DefinedAbsolute::NumOutputSections;
76 static Chunk *makeImportThunk(DefinedImportData *S, uint16_t Machine) {
78 return make<ImportThunkChunkX64>(S);
80 return make<ImportThunkChunkX86>(S);
82 return make<ImportThunkChunkARM64>(S);
83 assert(Machine == ARMNT);
84 return make<ImportThunkChunkARM>(S);
87 DefinedImportThunk::DefinedImportThunk(StringRef Name, DefinedImportData *S,
89 : Defined(DefinedImportThunkKind, Name), WrappedSym(S),
90 Data(makeImportThunk(S, Machine)) {}
92 Defined *Undefined::getWeakAlias() {
93 // A weak alias may be a weak alias to another symbol, so check recursively.
94 for (Symbol *A = WeakAlias; A; A = cast<Undefined>(A)->WeakAlias)
95 if (auto *D = dyn_cast<Defined>(A))