diff options
Diffstat (limited to 'llvm/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldELF.cpp')
| -rw-r--r-- | llvm/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldELF.cpp | 167 |
1 files changed, 65 insertions, 102 deletions
diff --git a/llvm/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldELF.cpp b/llvm/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldELF.cpp index 6381c0495c3..bbffdfb3941 100644 --- a/llvm/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldELF.cpp +++ b/llvm/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldELF.cpp @@ -12,6 +12,7 @@ //===----------------------------------------------------------------------===// #include "RuntimeDyldELF.h" +#include "RuntimeDyldCheckerImpl.h" #include "llvm/ADT/IntervalMap.h" #include "llvm/ADT/STLExtras.h" #include "llvm/ADT/StringRef.h" @@ -185,7 +186,7 @@ namespace llvm { RuntimeDyldELF::RuntimeDyldELF(RuntimeDyld::MemoryManager &MemMgr, RuntimeDyld::SymbolResolver &Resolver) - : RuntimeDyldImpl(MemMgr, Resolver) {} + : RuntimeDyldImpl(MemMgr, Resolver), GOTSectionID(0), CurrentGOTIndex(0) {} RuntimeDyldELF::~RuntimeDyldELF() {} void RuntimeDyldELF::registerEHFrames() { @@ -245,27 +246,16 @@ void RuntimeDyldELF::resolveX86_64Relocation(const SectionEntry &Section, << format("%p\n", Section.Address + Offset)); break; } - case ELF::R_X86_64_GOTPCREL: { - // findGOTEntry returns the 'G + GOT' part of the relocation calculation - // based on the load/target address of the GOT (not the current/local addr). - uint64_t GOTAddr = findGOTEntry(Value, SymOffset); - uint64_t FinalAddress = Section.LoadAddress + Offset; - // The processRelocationRef method combines the symbol offset and the addend - // and in most cases that's what we want. For this relocation type, we need - // the raw addend, so we subtract the symbol offset to get it. - int64_t RealOffset = GOTAddr + Addend - SymOffset - FinalAddress; - assert(RealOffset <= INT32_MAX && RealOffset >= INT32_MIN); - int32_t TruncOffset = (RealOffset & 0xFFFFFFFF); - support::ulittle32_t::ref(Section.Address + Offset) = TruncOffset; - break; - } case ELF::R_X86_64_PC32: { // Get the placeholder value from the generated object since // a previous relocation attempt may have overwritten the loaded version support::ulittle32_t::ref Placeholder( (void *)(Section.ObjAddress + Offset)); uint64_t FinalAddress = Section.LoadAddress + Offset; - int64_t RealOffset = Placeholder + Value + Addend - FinalAddress; + int64_t RealOffset = Value + Addend - FinalAddress; + // Don't add the placeholder if this is a stub + if (Offset < Section.Size) + RealOffset += Placeholder; assert(RealOffset <= INT32_MAX && RealOffset >= INT32_MIN); int32_t TruncOffset = (RealOffset & 0xFFFFFFFF); support::ulittle32_t::ref(Section.Address + Offset) = TruncOffset; @@ -277,8 +267,10 @@ void RuntimeDyldELF::resolveX86_64Relocation(const SectionEntry &Section, support::ulittle64_t::ref Placeholder( (void *)(Section.ObjAddress + Offset)); uint64_t FinalAddress = Section.LoadAddress + Offset; - support::ulittle64_t::ref(Section.Address + Offset) = - Placeholder + Value + Addend - FinalAddress; + int64_t RealOffset = Value + Addend - FinalAddress; + if (Offset < Section.Size) + RealOffset += Placeholder; + support::ulittle64_t::ref(Section.Address + Offset) = RealOffset; break; } } @@ -1323,16 +1315,18 @@ relocation_iterator RuntimeDyldELF::processRelocationRef( Stubs[Value] = StubOffset; createStubFunction((uint8_t *)StubAddress); - // Create a GOT entry for the external function. - GOTEntries.push_back(Value); - - // Make our stub function a relative call to the GOT entry. - RelocationEntry RE(SectionID, StubOffset + 2, ELF::R_X86_64_GOTPCREL, - -4); - addRelocationForSymbol(RE, Value.SymbolName); - // Bump our stub offset counter Section.StubOffset = StubOffset + getMaxStubSize(); + + // Allocate a GOT Entry + uint64_t GOTOffset = allocateGOTEntries(SectionID, 1); + + // The load of the GOT address has an addend of -4 + resolveGOTOffsetRelocation(SectionID, StubOffset + 2, GOTOffset - 4); + + // Fill in the value of the symbol we're targeting into the GOT + addRelocationForSymbol(computeGOTOffsetRE(SectionID,GOTOffset,0,ELF::R_X86_64_64), + Value.SymbolName); } // Make the target call a call into the stub table. @@ -1343,10 +1337,17 @@ relocation_iterator RuntimeDyldELF::processRelocationRef( Value.Offset); addRelocationForSection(RE, Value.SectionID); } + } else if (Arch == Triple::x86_64 && RelType == ELF::R_X86_64_GOTPCREL) { + uint64_t GOTOffset = allocateGOTEntries(SectionID, 1); + resolveGOTOffsetRelocation(SectionID, Offset, GOTOffset + Addend); + + // Fill in the value of the symbol we're targeting into the GOT + RelocationEntry RE = computeGOTOffsetRE(SectionID, GOTOffset, Value.Offset, ELF::R_X86_64_64); + if (Value.SymbolName) + addRelocationForSymbol(RE, Value.SymbolName); + else + addRelocationForSection(RE, Value.SectionID); } else { - if (Arch == Triple::x86_64 && RelType == ELF::R_X86_64_GOTPCREL) { - GOTEntries.push_back(Value); - } RelocationEntry RE(SectionID, Offset, RelType, Value.Addend, Value.Offset); if (Value.SymbolName) addRelocationForSymbol(RE, Value.SymbolName); @@ -1356,22 +1357,6 @@ relocation_iterator RuntimeDyldELF::processRelocationRef( return ++RelI; } -void RuntimeDyldELF::updateGOTEntries(StringRef Name, uint64_t Addr) { - - SmallVectorImpl<std::pair<SID, GOTRelocations>>::iterator it; - SmallVectorImpl<std::pair<SID, GOTRelocations>>::iterator end = GOTs.end(); - - for (it = GOTs.begin(); it != end; ++it) { - GOTRelocations &GOTEntries = it->second; - for (int i = 0, e = GOTEntries.size(); i != e; ++i) { - if (GOTEntries[i].SymbolName != nullptr && - GOTEntries[i].SymbolName == Name) { - GOTEntries[i].Offset = Addr; - } - } - } -} - size_t RuntimeDyldELF::getGOTEntrySize() { // We don't use the GOT in all of these cases, but it's essentially free // to put them all here. @@ -1398,75 +1383,50 @@ size_t RuntimeDyldELF::getGOTEntrySize() { return Result; } -uint64_t RuntimeDyldELF::findGOTEntry(uint64_t LoadAddress, uint64_t Offset) { - - const size_t GOTEntrySize = getGOTEntrySize(); - - SmallVectorImpl<std::pair<SID, GOTRelocations>>::const_iterator it; - SmallVectorImpl<std::pair<SID, GOTRelocations>>::const_iterator end = - GOTs.end(); - - int GOTIndex = -1; - for (it = GOTs.begin(); it != end; ++it) { - SID GOTSectionID = it->first; - const GOTRelocations &GOTEntries = it->second; - - // Find the matching entry in our vector. - uint64_t SymbolOffset = 0; - for (int i = 0, e = GOTEntries.size(); i != e; ++i) { - if (!GOTEntries[i].SymbolName) { - if (getSectionLoadAddress(GOTEntries[i].SectionID) == LoadAddress && - GOTEntries[i].Offset == Offset) { - GOTIndex = i; - SymbolOffset = GOTEntries[i].Offset; - break; - } - } else { - // GOT entries for external symbols use the addend as the address when - // the external symbol has been resolved. - if (GOTEntries[i].Offset == LoadAddress) { - GOTIndex = i; - // Don't use the Addend here. The relocation handler will use it. - break; - } - } - } - - if (GOTIndex != -1) { - if (GOTEntrySize == sizeof(uint64_t)) { - uint64_t *LocalGOTAddr = (uint64_t *)getSectionAddress(GOTSectionID); - // Fill in this entry with the address of the symbol being referenced. - LocalGOTAddr[GOTIndex] = LoadAddress + SymbolOffset; - } else { - uint32_t *LocalGOTAddr = (uint32_t *)getSectionAddress(GOTSectionID); - // Fill in this entry with the address of the symbol being referenced. - LocalGOTAddr[GOTIndex] = (uint32_t)(LoadAddress + SymbolOffset); - } - - // Calculate the load address of this entry - return getSectionLoadAddress(GOTSectionID) + (GOTIndex * GOTEntrySize); - } +uint64_t RuntimeDyldELF::allocateGOTEntries(unsigned SectionID, unsigned no) +{ + (void)SectionID; // The GOT Section is the same for all section in the object file + if (GOTSectionID == 0) { + GOTSectionID = Sections.size(); + // Reserve a section id. We'll allocate the section later + // once we know the total size + Sections.push_back(SectionEntry(".got", 0, 0, 0)); } + uint64_t StartOffset = CurrentGOTIndex * getGOTEntrySize(); + CurrentGOTIndex += no; + return StartOffset; +} - assert(GOTIndex != -1 && "Unable to find requested GOT entry."); - return 0; +void RuntimeDyldELF::resolveGOTOffsetRelocation(unsigned SectionID, uint64_t Offset, uint64_t GOTOffset) +{ + // Fill in the relative address of the GOT Entry into the stub + RelocationEntry GOTRE(SectionID, Offset, ELF::R_X86_64_PC32, GOTOffset); + addRelocationForSection(GOTRE, GOTSectionID); +} + +RelocationEntry RuntimeDyldELF::computeGOTOffsetRE(unsigned SectionID, uint64_t GOTOffset, uint64_t SymbolOffset, + uint32_t Type) +{ + (void)SectionID; // The GOT Section is the same for all section in the object file + return RelocationEntry(GOTSectionID, GOTOffset, Type, SymbolOffset); } void RuntimeDyldELF::finalizeLoad(const ObjectFile &Obj, ObjSectionToIDMap &SectionMap) { // If necessary, allocate the global offset table - size_t numGOTEntries = GOTEntries.size(); - if (numGOTEntries != 0) { + if (GOTSectionID != 0) { // Allocate memory for the section - unsigned SectionID = Sections.size(); - size_t TotalSize = numGOTEntries * getGOTEntrySize(); + size_t TotalSize = CurrentGOTIndex * getGOTEntrySize(); uint8_t *Addr = MemMgr.allocateDataSection(TotalSize, getGOTEntrySize(), - SectionID, ".got", false); + GOTSectionID, ".got", false); if (!Addr) report_fatal_error("Unable to allocate memory for GOT!"); - GOTs.push_back(std::make_pair(SectionID, GOTEntries)); - Sections.push_back(SectionEntry(".got", Addr, TotalSize, 0)); + Sections[GOTSectionID] = SectionEntry(".got", Addr, TotalSize, 0); + + if (Checker) + Checker->registerSection(Obj.getFileName(), GOTSectionID); + // For now, initialize all GOT entries to zero. We'll fill them in as // needed when GOT-based relocations are applied. memset(Addr, 0, TotalSize); @@ -1483,6 +1443,9 @@ void RuntimeDyldELF::finalizeLoad(const ObjectFile &Obj, break; } } + + GOTSectionID = 0; + CurrentGOTIndex = 0; } bool RuntimeDyldELF::isCompatibleFile(const object::ObjectFile &Obj) const { |
