forked from OSchip/llvm-project
93 lines
2.6 KiB
C++
93 lines
2.6 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 "InputSection.h"
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#include "Error.h"
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#include "InputFiles.h"
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#include "llvm/ADT/STLExtras.h"
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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::elf2;
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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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// Returns 1, 0 or -1 if this symbol should take precedence
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// over the Other, tie or lose, respectively.
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template <class ELFT> int SymbolBody::compare(SymbolBody *Other) {
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assert(!isLazy() && !Other->isLazy());
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std::pair<bool, bool> L(isDefined(), !isWeak());
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std::pair<bool, bool> R(Other->isDefined(), !Other->isWeak());
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// Normalize
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if (L > R)
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return -Other->compare<ELFT>(this);
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uint8_t LV = getMostConstrainingVisibility();
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uint8_t RV = Other->getMostConstrainingVisibility();
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MostConstrainingVisibility = getMinVisibility(LV, RV);
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Other->MostConstrainingVisibility = MostConstrainingVisibility;
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IsUsedInRegularObj |= Other->IsUsedInRegularObj;
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Other->IsUsedInRegularObj |= IsUsedInRegularObj;
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if (L != R)
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return -1;
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if (!L.first || !L.second)
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return 1;
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if (isShared())
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return -1;
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if (Other->isShared())
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return 1;
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if (isCommon()) {
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if (!Other->isCommon())
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return -1;
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auto *ThisC = cast<DefinedCommon<ELFT>>(this);
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auto *OtherC = cast<DefinedCommon<ELFT>>(Other);
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typename DefinedCommon<ELFT>::uintX_t MaxAlign =
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std::max(ThisC->MaxAlignment, OtherC->MaxAlignment);
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if (ThisC->Sym.st_size >= OtherC->Sym.st_size) {
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ThisC->MaxAlignment = MaxAlign;
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return 1;
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}
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OtherC->MaxAlignment = MaxAlign;
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return -1;
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}
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if (Other->isCommon())
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return 1;
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return 0;
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}
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std::unique_ptr<InputFile> Lazy::getMember() {
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MemoryBufferRef MBRef = File->getMember(&Sym);
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// getMember returns an empty buffer if the member was already
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// read from the library.
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if (MBRef.getBuffer().empty())
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return std::unique_ptr<InputFile>(nullptr);
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return createELFFile<ObjectFile>(MBRef);
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}
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template int SymbolBody::compare<ELF32LE>(SymbolBody *Other);
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template int SymbolBody::compare<ELF32BE>(SymbolBody *Other);
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template int SymbolBody::compare<ELF64LE>(SymbolBody *Other);
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template int SymbolBody::compare<ELF64BE>(SymbolBody *Other);
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