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diff --git a/lib/ReaderWriter/ELF/X86_64/X86_64RelocationPass.cpp b/lib/ReaderWriter/ELF/X86_64/X86_64RelocationPass.cpp
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-//===- lib/ReaderWriter/ELF/X86_64/X86_64RelocationPass.cpp ---------------===//
-//
-// The LLVM Linker
-//
-// This file is distributed under the University of Illinois Open Source
-// License. See LICENSE.TXT for details.
-//
-//===----------------------------------------------------------------------===//
-///
-/// \file
-/// \brief Defines the relocation processing pass for x86-64. This includes
-/// GOT and PLT entries, TLS, COPY, and ifunc.
-///
-/// This is based on section 4.4.1 of the AMD64 ABI (no stable URL as of Oct,
-/// 2013).
-///
-/// This also includes aditional behaivor that gnu-ld and gold implement but
-/// which is not specified anywhere.
-///
-//===----------------------------------------------------------------------===//
-
-#include "X86_64RelocationPass.h"
-#include "Atoms.h"
-#include "X86_64LinkingContext.h"
-#include "lld/Core/Simple.h"
-#include "llvm/ADT/DenseMap.h"
-#include "llvm/ADT/STLExtras.h"
-
-using namespace lld;
-using namespace lld::elf;
-using namespace llvm::ELF;
-
-// .got values
-static const uint8_t x86_64GotAtomContent[8] = {0};
-
-// .plt value (entry 0)
-static const uint8_t x86_64Plt0AtomContent[16] = {
- 0xff, 0x35, 0x00, 0x00, 0x00, 0x00, // pushq GOT+8(%rip)
- 0xff, 0x25, 0x00, 0x00, 0x00, 0x00, // jmp *GOT+16(%rip)
- 0x90, 0x90, 0x90, 0x90 // nopnopnop
-};
-
-// .plt values (other entries)
-static const uint8_t x86_64PltAtomContent[16] = {
- 0xff, 0x25, 0x00, 0x00, 0x00, 0x00, // jmpq *gotatom(%rip)
- 0x68, 0x00, 0x00, 0x00, 0x00, // pushq reloc-index
- 0xe9, 0x00, 0x00, 0x00, 0x00 // jmpq plt[-1]
-};
-
-// TLS GD Entry
-static const uint8_t x86_64GotTlsGdAtomContent[] = {
- 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
- 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
-};
-
-namespace {
-/// \brief Atoms that are used by X86_64 dynamic linking
-class X86_64GOTAtom : public GOTAtom {
-public:
- X86_64GOTAtom(const File &f, StringRef secName) : GOTAtom(f, secName) {}
-
- ArrayRef<uint8_t> rawContent() const override {
- return ArrayRef<uint8_t>(x86_64GotAtomContent, 8);
- }
-};
-
-/// \brief X86_64 GOT TLS GD entry.
-class GOTTLSGdAtom : public X86_64GOTAtom {
-public:
- GOTTLSGdAtom(const File &f, StringRef secName) : X86_64GOTAtom(f, secName) {}
-
- ArrayRef<uint8_t> rawContent() const override {
- return llvm::makeArrayRef(x86_64GotTlsGdAtomContent);
- }
-};
-
-class X86_64PLT0Atom : public PLT0Atom {
-public:
- X86_64PLT0Atom(const File &f) : PLT0Atom(f) {}
- ArrayRef<uint8_t> rawContent() const override {
- return ArrayRef<uint8_t>(x86_64Plt0AtomContent, 16);
- }
-};
-
-class X86_64PLTAtom : public PLTAtom {
-public:
- X86_64PLTAtom(const File &f, StringRef secName) : PLTAtom(f, secName) {}
-
- ArrayRef<uint8_t> rawContent() const override {
- return ArrayRef<uint8_t>(x86_64PltAtomContent, 16);
- }
-};
-
-class ELFPassFile : public SimpleFile {
-public:
- ELFPassFile(const ELFLinkingContext &eti) : SimpleFile("ELFPassFile") {
- setOrdinal(eti.getNextOrdinalAndIncrement());
- }
-
- llvm::BumpPtrAllocator _alloc;
-};
-
-/// \brief CRTP base for handling relocations.
-template <class Derived> class RelocationPass : public Pass {
- /// \brief Handle a specific reference.
- void handleReference(const DefinedAtom &atom, const Reference &ref) {
- if (ref.kindNamespace() != Reference::KindNamespace::ELF)
- return;
- assert(ref.kindArch() == Reference::KindArch::x86_64);
- switch (ref.kindValue()) {
- case R_X86_64_16:
- case R_X86_64_32:
- case R_X86_64_32S:
- case R_X86_64_64:
- case R_X86_64_PC16:
- case R_X86_64_PC32:
- case R_X86_64_PC64:
- static_cast<Derived *>(this)->handlePlain(ref);
- break;
- case R_X86_64_PLT32:
- static_cast<Derived *>(this)->handlePLT32(ref);
- break;
- case R_X86_64_GOT32:
- case R_X86_64_GOTPC32:
- case R_X86_64_GOTPCREL:
- case R_X86_64_GOTOFF64:
- static_cast<Derived *>(this)->handleGOT(ref);
- break;
- case R_X86_64_GOTTPOFF: // GOT Thread Pointer Offset
- static_cast<Derived *>(this)->handleGOTTPOFF(ref);
- break;
- case R_X86_64_TLSGD:
- static_cast<Derived *>(this)->handleTLSGd(ref);
- break;
- }
- }
-
-protected:
- /// \brief get the PLT entry for a given IFUNC Atom.
- ///
- /// If the entry does not exist. Both the GOT and PLT entry is created.
- const PLTAtom *getIFUNCPLTEntry(const DefinedAtom *da) {
- auto plt = _pltMap.find(da);
- if (plt != _pltMap.end())
- return plt->second;
- auto ga = new (_file._alloc) X86_64GOTAtom(_file, ".got.plt");
- ga->addReferenceELF_x86_64(R_X86_64_IRELATIVE, 0, da, 0);
- auto pa = new (_file._alloc) X86_64PLTAtom(_file, ".plt");
- pa->addReferenceELF_x86_64(R_X86_64_PC32, 2, ga, -4);
-#ifndef NDEBUG
- ga->_name = "__got_ifunc_";
- ga->_name += da->name();
- pa->_name = "__plt_ifunc_";
- pa->_name += da->name();
-#endif
- _gotMap[da] = ga;
- _pltMap[da] = pa;
- _gotVector.push_back(ga);
- _pltVector.push_back(pa);
- return pa;
- }
-
- /// \brief Redirect the call to the PLT stub for the target IFUNC.
- ///
- /// This create a PLT and GOT entry for the IFUNC if one does not exist. The
- /// GOT entry and a IRELATIVE relocation to the original target resolver.
- std::error_code handleIFUNC(const Reference &ref) {
- auto target = dyn_cast_or_null<const DefinedAtom>(ref.target());
- if (target && target->contentType() == DefinedAtom::typeResolver)
- const_cast<Reference &>(ref).setTarget(getIFUNCPLTEntry(target));
- return std::error_code();
- }
-
- /// \brief Create a GOT entry for the TP offset of a TLS atom.
- const GOTAtom *getGOTTPOFF(const Atom *atom) {
- auto got = _gotMap.find(atom);
- if (got == _gotMap.end()) {
- auto g = new (_file._alloc) X86_64GOTAtom(_file, ".got");
- g->addReferenceELF_x86_64(R_X86_64_TPOFF64, 0, atom, 0);
-#ifndef NDEBUG
- g->_name = "__got_tls_";
- g->_name += atom->name();
-#endif
- _gotMap[atom] = g;
- _gotVector.push_back(g);
- return g;
- }
- return got->second;
- }
-
- /// \brief Create a TPOFF64 GOT entry.
- std::error_code handleGOTTPOFF(const Reference &ref) {
- if (isa<DefinedAtom>(ref.target())) {
- const_cast<Reference &>(ref).setTarget(getGOTTPOFF(ref.target()));
- }
- return std::error_code();
- }
-
- /// \brief Create a TLS GOT entry with DTPMOD64/DTPOFF64 dynamic relocations.
- void handleTLSGd(const Reference &ref) {
- const_cast<Reference &>(ref).setTarget(getTLSGdGOTEntry(ref.target()));
- }
-
- /// \brief Create a GOT entry containing 0.
- const GOTAtom *getNullGOT() {
- if (!_null) {
- _null = new (_file._alloc) X86_64GOTAtom(_file, ".got.plt");
-#ifndef NDEBUG
- _null->_name = "__got_null";
-#endif
- }
- return _null;
- }
-
- const GOTAtom *getGOT(const DefinedAtom *da) {
- auto got = _gotMap.find(da);
- if (got == _gotMap.end()) {
- auto g = new (_file._alloc) X86_64GOTAtom(_file, ".got");
- g->addReferenceELF_x86_64(R_X86_64_64, 0, da, 0);
-#ifndef NDEBUG
- g->_name = "__got_";
- g->_name += da->name();
-#endif
- _gotMap[da] = g;
- _gotVector.push_back(g);
- return g;
- }
- return got->second;
- }
-
- const GOTAtom *getTLSGdGOTEntry(const Atom *a) {
- auto got = _gotTLSGdMap.find(a);
- if (got != _gotTLSGdMap.end())
- return got->second;
-
- auto ga = new (_file._alloc) GOTTLSGdAtom(_file, ".got");
- _gotTLSGdMap[a] = ga;
-
- _tlsGotVector.push_back(ga);
- ga->addReferenceELF_x86_64(R_X86_64_DTPMOD64, 0, a, 0);
- ga->addReferenceELF_x86_64(R_X86_64_DTPOFF64, 8, a, 0);
-
- return ga;
- }
-
-public:
- RelocationPass(const ELFLinkingContext &ctx) : _file(ctx), _ctx(ctx) {}
-
- /// \brief Do the pass.
- ///
- /// The goal here is to first process each reference individually. Each call
- /// to handleReference may modify the reference itself and/or create new
- /// atoms which must be stored in one of the maps below.
- ///
- /// After all references are handled, the atoms created during that are all
- /// added to mf.
- std::error_code perform(SimpleFile &mf) override {
- ScopedTask task(getDefaultDomain(), "X86-64 GOT/PLT Pass");
- // Process all references.
- for (const auto &atom : mf.defined())
- for (const auto &ref : *atom)
- handleReference(*atom, *ref);
-
- // Add all created atoms to the link.
- uint64_t ordinal = 0;
- if (_plt0) {
- _plt0->setOrdinal(ordinal++);
- mf.addAtom(*_plt0);
- }
- for (auto &plt : _pltVector) {
- plt->setOrdinal(ordinal++);
- mf.addAtom(*plt);
- }
- if (_null) {
- _null->setOrdinal(ordinal++);
- mf.addAtom(*_null);
- }
- if (_plt0) {
- _got0->setOrdinal(ordinal++);
- _got1->setOrdinal(ordinal++);
- mf.addAtom(*_got0);
- mf.addAtom(*_got1);
- }
- for (auto &got : _gotVector) {
- got->setOrdinal(ordinal++);
- mf.addAtom(*got);
- }
- for (auto &got : _tlsGotVector) {
- got->setOrdinal(ordinal++);
- mf.addAtom(*got);
- }
- for (auto obj : _objectVector) {
- obj->setOrdinal(ordinal++);
- mf.addAtom(*obj);
- }
- return std::error_code();
- }
-
-protected:
- /// \brief Owner of all the Atoms created by this pass.
- ELFPassFile _file;
- const ELFLinkingContext &_ctx;
-
- /// \brief Map Atoms to their GOT entries.
- llvm::DenseMap<const Atom *, GOTAtom *> _gotMap;
-
- /// \brief Map Atoms to their PLT entries.
- llvm::DenseMap<const Atom *, PLTAtom *> _pltMap;
-
- /// \brief Map Atoms to TLS GD GOT entries.
- llvm::DenseMap<const Atom *, GOTAtom *> _gotTLSGdMap;
-
- /// \brief Map Atoms to their Object entries.
- llvm::DenseMap<const Atom *, ObjectAtom *> _objectMap;
-
- /// \brief the list of GOT/PLT atoms
- std::vector<GOTAtom *> _gotVector;
- std::vector<PLTAtom *> _pltVector;
- std::vector<ObjectAtom *> _objectVector;
-
- /// \brief the list of TLS GOT atoms.
- std::vector<GOTAtom *> _tlsGotVector;
-
- /// \brief GOT entry that is always 0. Used for undefined weaks.
- GOTAtom *_null = nullptr;
-
- /// \brief The got and plt entries for .PLT0. This is used to call into the
- /// dynamic linker for symbol resolution.
- /// @{
- PLT0Atom *_plt0 = nullptr;
- GOTAtom *_got0 = nullptr;
- GOTAtom *_got1 = nullptr;
- /// @}
-};
-
-/// This implements the static relocation model. Meaning GOT and PLT entries are
-/// not created for references that can be directly resolved. These are
-/// converted to a direct relocation. For entries that do require a GOT or PLT
-/// entry, that entry is statically bound.
-///
-/// TLS always assumes module 1 and attempts to remove indirection.
-class StaticRelocationPass final
- : public RelocationPass<StaticRelocationPass> {
-public:
- StaticRelocationPass(const elf::X86_64LinkingContext &ctx)
- : RelocationPass(ctx) {}
-
- std::error_code handlePlain(const Reference &ref) { return handleIFUNC(ref); }
-
- std::error_code handlePLT32(const Reference &ref) {
- // __tls_get_addr is handled elsewhere.
- if (ref.target() && ref.target()->name() == "__tls_get_addr") {
- const_cast<Reference &>(ref).setKindValue(R_X86_64_NONE);
- return std::error_code();
- }
- // Static code doesn't need PLTs.
- const_cast<Reference &>(ref).setKindValue(R_X86_64_PC32);
- // Handle IFUNC.
- if (const DefinedAtom *da =
- dyn_cast_or_null<const DefinedAtom>(ref.target()))
- if (da->contentType() == DefinedAtom::typeResolver)
- return handleIFUNC(ref);
- return std::error_code();
- }
-
- std::error_code handleGOT(const Reference &ref) {
- if (isa<UndefinedAtom>(ref.target()))
- const_cast<Reference &>(ref).setTarget(getNullGOT());
- else if (const DefinedAtom *da = dyn_cast<const DefinedAtom>(ref.target()))
- const_cast<Reference &>(ref).setTarget(getGOT(da));
- return std::error_code();
- }
-};
-
-class DynamicRelocationPass final
- : public RelocationPass<DynamicRelocationPass> {
-public:
- DynamicRelocationPass(const elf::X86_64LinkingContext &ctx)
- : RelocationPass(ctx) {}
-
- const PLT0Atom *getPLT0() {
- if (_plt0)
- return _plt0;
- // Fill in the null entry.
- getNullGOT();
- _plt0 = new (_file._alloc) X86_64PLT0Atom(_file);
- _got0 = new (_file._alloc) X86_64GOTAtom(_file, ".got.plt");
- _got1 = new (_file._alloc) X86_64GOTAtom(_file, ".got.plt");
- _plt0->addReferenceELF_x86_64(R_X86_64_PC32, 2, _got0, -4);
- _plt0->addReferenceELF_x86_64(R_X86_64_PC32, 8, _got1, -4);
-#ifndef NDEBUG
- _got0->_name = "__got0";
- _got1->_name = "__got1";
-#endif
- return _plt0;
- }
-
- const PLTAtom *getPLTEntry(const Atom *a) {
- auto plt = _pltMap.find(a);
- if (plt != _pltMap.end())
- return plt->second;
- auto ga = new (_file._alloc) X86_64GOTAtom(_file, ".got.plt");
- ga->addReferenceELF_x86_64(R_X86_64_JUMP_SLOT, 0, a, 0);
- auto pa = new (_file._alloc) X86_64PLTAtom(_file, ".plt");
- pa->addReferenceELF_x86_64(R_X86_64_PC32, 2, ga, -4);
- pa->addReferenceELF_x86_64(LLD_R_X86_64_GOTRELINDEX, 7, ga, 0);
- pa->addReferenceELF_x86_64(R_X86_64_PC32, 12, getPLT0(), -4);
- // Set the starting address of the got entry to the second instruction in
- // the plt entry.
- ga->addReferenceELF_x86_64(R_X86_64_64, 0, pa, 6);
-#ifndef NDEBUG
- ga->_name = "__got_";
- ga->_name += a->name();
- pa->_name = "__plt_";
- pa->_name += a->name();
-#endif
- _gotMap[a] = ga;
- _pltMap[a] = pa;
- _gotVector.push_back(ga);
- _pltVector.push_back(pa);
- return pa;
- }
-
- const ObjectAtom *getObjectEntry(const SharedLibraryAtom *a) {
- auto obj = _objectMap.find(a);
- if (obj != _objectMap.end())
- return obj->second;
-
- auto oa = new (_file._alloc) ObjectAtom(_file);
- // This needs to point to the atom that we just created.
- oa->addReferenceELF_x86_64(R_X86_64_COPY, 0, oa, 0);
-
- oa->_name = a->name();
- oa->_size = a->size();
-
- _objectMap[a] = oa;
- _objectVector.push_back(oa);
- return oa;
- }
-
- std::error_code handlePlain(const Reference &ref) {
- if (!ref.target())
- return std::error_code();
- if (auto sla = dyn_cast<SharedLibraryAtom>(ref.target())) {
- if (sla->type() == SharedLibraryAtom::Type::Data)
- const_cast<Reference &>(ref).setTarget(getObjectEntry(sla));
- else if (sla->type() == SharedLibraryAtom::Type::Code)
- const_cast<Reference &>(ref).setTarget(getPLTEntry(sla));
- } else
- return handleIFUNC(ref);
- return std::error_code();
- }
-
- std::error_code handlePLT32(const Reference &ref) {
- // Turn this into a PC32 to the PLT entry.
- const_cast<Reference &>(ref).setKindValue(R_X86_64_PC32);
- // Handle IFUNC.
- if (const DefinedAtom *da =
- dyn_cast_or_null<const DefinedAtom>(ref.target()))
- if (da->contentType() == DefinedAtom::typeResolver)
- return handleIFUNC(ref);
- // If it is undefined at link time, push the work to the dynamic linker by
- // creating a PLT entry
- if (isa<SharedLibraryAtom>(ref.target()) ||
- isa<UndefinedAtom>(ref.target()))
- const_cast<Reference &>(ref).setTarget(getPLTEntry(ref.target()));
- return std::error_code();
- }
-
- const GOTAtom *getSharedGOT(const Atom *a) {
- auto got = _gotMap.find(a);
- if (got == _gotMap.end()) {
- auto g = new (_file._alloc) X86_64GOTAtom(_file, ".got");
- g->addReferenceELF_x86_64(R_X86_64_GLOB_DAT, 0, a, 0);
-#ifndef NDEBUG
- g->_name = "__got_";
- g->_name += a->name();
-#endif
- _gotMap[a] = g;
- _gotVector.push_back(g);
- return g;
- }
- return got->second;
- }
-
- std::error_code handleGOT(const Reference &ref) {
- if (const DefinedAtom *da = dyn_cast<const DefinedAtom>(ref.target()))
- const_cast<Reference &>(ref).setTarget(getGOT(da));
- // Handle undefined atoms in the same way as shared lib atoms: to be
- // resolved at run time.
- else if (isa<SharedLibraryAtom>(ref.target()) ||
- isa<UndefinedAtom>(ref.target()))
- const_cast<Reference &>(ref).setTarget(getSharedGOT(ref.target()));
- return std::error_code();
- }
-};
-} // end anon namespace
-
-std::unique_ptr<Pass>
-lld::elf::createX86_64RelocationPass(const X86_64LinkingContext &ctx) {
- switch (ctx.getOutputELFType()) {
- case llvm::ELF::ET_EXEC:
- if (ctx.isDynamic())
- return llvm::make_unique<DynamicRelocationPass>(ctx);
- return llvm::make_unique<StaticRelocationPass>(ctx);
- case llvm::ELF::ET_DYN:
- return llvm::make_unique<DynamicRelocationPass>(ctx);
- case llvm::ELF::ET_REL:
- return nullptr;
- default:
- llvm_unreachable("Unhandled output file type");
- }
-}
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