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Diffstat (limited to 'contrib/llvm/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldELF.cpp')
| -rw-r--r-- | contrib/llvm/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldELF.cpp | 262 |
1 files changed, 262 insertions, 0 deletions
diff --git a/contrib/llvm/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldELF.cpp b/contrib/llvm/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldELF.cpp new file mode 100644 index 0000000..57fefee --- /dev/null +++ b/contrib/llvm/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldELF.cpp @@ -0,0 +1,262 @@ +//===-- RuntimeDyldELF.cpp - Run-time dynamic linker for MC-JIT -*- C++ -*-===// +// +// The LLVM Compiler Infrastructure +// +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// +// +// Implementation of ELF support for the MC-JIT runtime dynamic linker. +// +//===----------------------------------------------------------------------===// + +#define DEBUG_TYPE "dyld" +#include "llvm/ADT/OwningPtr.h" +#include "llvm/ADT/StringRef.h" +#include "llvm/ADT/STLExtras.h" +#include "llvm/ADT/IntervalMap.h" +#include "RuntimeDyldELF.h" +#include "llvm/Object/ObjectFile.h" +#include "llvm/Support/ELF.h" +#include "llvm/ADT/Triple.h" +using namespace llvm; +using namespace llvm::object; + +namespace llvm { + + +void RuntimeDyldELF::resolveX86_64Relocation(uint8_t *LocalAddress, + uint64_t FinalAddress, + uint64_t Value, + uint32_t Type, + int64_t Addend) { + switch (Type) { + default: + llvm_unreachable("Relocation type not implemented yet!"); + break; + case ELF::R_X86_64_64: { + uint64_t *Target = (uint64_t*)(LocalAddress); + *Target = Value + Addend; + break; + } + case ELF::R_X86_64_32: + case ELF::R_X86_64_32S: { + Value += Addend; + // FIXME: Handle the possibility of this assertion failing + assert((Type == ELF::R_X86_64_32 && !(Value & 0xFFFFFFFF00000000ULL)) || + (Type == ELF::R_X86_64_32S && + (Value & 0xFFFFFFFF00000000ULL) == 0xFFFFFFFF00000000ULL)); + uint32_t TruncatedAddr = (Value & 0xFFFFFFFF); + uint32_t *Target = reinterpret_cast<uint32_t*>(LocalAddress); + *Target = TruncatedAddr; + break; + } + case ELF::R_X86_64_PC32: { + uint32_t *Placeholder = reinterpret_cast<uint32_t*>(LocalAddress); + int64_t RealOffset = *Placeholder + Value + Addend - FinalAddress; + assert(RealOffset <= 214783647 && RealOffset >= -214783648); + int32_t TruncOffset = (RealOffset & 0xFFFFFFFF); + *Placeholder = TruncOffset; + break; + } + } +} + +void RuntimeDyldELF::resolveX86Relocation(uint8_t *LocalAddress, + uint32_t FinalAddress, + uint32_t Value, + uint32_t Type, + int32_t Addend) { + switch (Type) { + case ELF::R_386_32: { + uint32_t *Target = (uint32_t*)(LocalAddress); + uint32_t Placeholder = *Target; + *Target = Placeholder + Value + Addend; + break; + } + case ELF::R_386_PC32: { + uint32_t *Placeholder = reinterpret_cast<uint32_t*>(LocalAddress); + uint32_t RealOffset = *Placeholder + Value + Addend - FinalAddress; + *Placeholder = RealOffset; + break; + } + default: + // There are other relocation types, but it appears these are the + // only ones currently used by the LLVM ELF object writer + llvm_unreachable("Relocation type not implemented yet!"); + break; + } +} + +void RuntimeDyldELF::resolveARMRelocation(uint8_t *LocalAddress, + uint32_t FinalAddress, + uint32_t Value, + uint32_t Type, + int32_t Addend) { + // TODO: Add Thumb relocations. + uint32_t* TargetPtr = (uint32_t*)LocalAddress; + Value += Addend; + + DEBUG(dbgs() << "resolveARMRelocation, LocalAddress: " << LocalAddress + << " FinalAddress: " << format("%p",FinalAddress) + << " Value: " << format("%x",Value) + << " Type: " << format("%x",Type) + << " Addend: " << format("%x",Addend) + << "\n"); + + switch(Type) { + default: + llvm_unreachable("Not implemented relocation type!"); + + // Just write 32bit value to relocation address + case ELF::R_ARM_ABS32 : + *TargetPtr = Value; + break; + + // Write first 16 bit of 32 bit value to the mov instruction. + // Last 4 bit should be shifted. + case ELF::R_ARM_MOVW_ABS_NC : + Value = Value & 0xFFFF; + *TargetPtr |= Value & 0xFFF; + *TargetPtr |= ((Value >> 12) & 0xF) << 16; + break; + + // Write last 16 bit of 32 bit value to the mov instruction. + // Last 4 bit should be shifted. + case ELF::R_ARM_MOVT_ABS : + Value = (Value >> 16) & 0xFFFF; + *TargetPtr |= Value & 0xFFF; + *TargetPtr |= ((Value >> 12) & 0xF) << 16; + break; + + // Write 24 bit relative value to the branch instruction. + case ELF::R_ARM_PC24 : // Fall through. + case ELF::R_ARM_CALL : // Fall through. + case ELF::R_ARM_JUMP24 : + int32_t RelValue = static_cast<int32_t>(Value - FinalAddress - 8); + RelValue = (RelValue & 0x03FFFFFC) >> 2; + *TargetPtr &= 0xFF000000; + *TargetPtr |= RelValue; + break; + } +} + +void RuntimeDyldELF::resolveRelocation(uint8_t *LocalAddress, + uint64_t FinalAddress, + uint64_t Value, + uint32_t Type, + int64_t Addend) { + switch (Arch) { + case Triple::x86_64: + resolveX86_64Relocation(LocalAddress, FinalAddress, Value, Type, Addend); + break; + case Triple::x86: + resolveX86Relocation(LocalAddress, (uint32_t)(FinalAddress & 0xffffffffL), + (uint32_t)(Value & 0xffffffffL), Type, + (uint32_t)(Addend & 0xffffffffL)); + break; + case Triple::arm: // Fall through. + case Triple::thumb: + resolveARMRelocation(LocalAddress, (uint32_t)(FinalAddress & 0xffffffffL), + (uint32_t)(Value & 0xffffffffL), Type, + (uint32_t)(Addend & 0xffffffffL)); + break; + default: llvm_unreachable("Unsupported CPU type!"); + } +} + +void RuntimeDyldELF::processRelocationRef(const ObjRelocationInfo &Rel, + const ObjectFile &Obj, + ObjSectionToIDMap &ObjSectionToID, + LocalSymbolMap &Symbols, + StubMap &Stubs) { + + uint32_t RelType = (uint32_t)(Rel.Type & 0xffffffffL); + intptr_t Addend = (intptr_t)Rel.AdditionalInfo; + RelocationValueRef Value; + StringRef TargetName; + const SymbolRef &Symbol = Rel.Symbol; + Symbol.getName(TargetName); + DEBUG(dbgs() << "\t\tRelType: " << RelType + << " Addend: " << Addend + << " TargetName: " << TargetName + << "\n"); + // First look the symbol in object file symbols. + LocalSymbolMap::iterator lsi = Symbols.find(TargetName.data()); + if (lsi != Symbols.end()) { + Value.SectionID = lsi->second.first; + Value.Addend = lsi->second.second; + } else { + // Second look the symbol in global symbol table. + StringMap<SymbolLoc>::iterator gsi = SymbolTable.find(TargetName.data()); + if (gsi != SymbolTable.end()) { + Value.SectionID = gsi->second.first; + Value.Addend = gsi->second.second; + } else { + SymbolRef::Type SymType; + Symbol.getType(SymType); + switch (SymType) { + case SymbolRef::ST_Debug: { + // TODO: Now ELF SymbolRef::ST_Debug = STT_SECTION, it's not obviously + // and can be changed by another developers. Maybe best way is add + // a new symbol type ST_Section to SymbolRef and use it. + section_iterator si = Obj.end_sections(); + Symbol.getSection(si); + if (si == Obj.end_sections()) + llvm_unreachable("Symbol section not found, bad object file format!"); + DEBUG(dbgs() << "\t\tThis is section symbol\n"); + Value.SectionID = findOrEmitSection((*si), true, ObjSectionToID); + Value.Addend = Addend; + break; + } + case SymbolRef::ST_Unknown: { + Value.SymbolName = TargetName.data(); + Value.Addend = Addend; + break; + } + default: + llvm_unreachable("Unresolved symbol type!"); + break; + } + } + } + DEBUG(dbgs() << "\t\tRel.SectionID: " << Rel.SectionID + << " Rel.Offset: " << Rel.Offset + << "\n"); + if (Arch == Triple::arm && + (RelType == ELF::R_ARM_PC24 || + RelType == ELF::R_ARM_CALL || + RelType == ELF::R_ARM_JUMP24)) { + // This is an ARM branch relocation, need to use a stub function. + DEBUG(dbgs() << "\t\tThis is an ARM branch relocation."); + SectionEntry &Section = Sections[Rel.SectionID]; + uint8_t *Target = Section.Address + Rel.Offset; + + // Look up for existing stub. + StubMap::const_iterator i = Stubs.find(Value); + if (i != Stubs.end()) { + resolveRelocation(Target, Section.LoadAddress, (uint64_t)Section.Address + + i->second, RelType, 0); + DEBUG(dbgs() << " Stub function found\n"); + } else { + // Create a new stub function. + DEBUG(dbgs() << " Create a new stub function\n"); + Stubs[Value] = Section.StubOffset; + uint8_t *StubTargetAddr = createStubFunction(Section.Address + + Section.StubOffset); + AddRelocation(Value, Rel.SectionID, + StubTargetAddr - Section.Address, ELF::R_ARM_ABS32); + resolveRelocation(Target, Section.LoadAddress, (uint64_t)Section.Address + + Section.StubOffset, RelType, 0); + Section.StubOffset += getMaxStubSize(); + } + } else + AddRelocation(Value, Rel.SectionID, Rel.Offset, RelType); +} + +bool RuntimeDyldELF::isCompatibleFormat(const MemoryBuffer *InputBuffer) const { + StringRef Magic = InputBuffer->getBuffer().slice(0, ELF::EI_NIDENT); + return (memcmp(Magic.data(), ELF::ElfMagic, strlen(ELF::ElfMagic))) == 0; +} +} // namespace llvm |
