diff options
Diffstat (limited to 'lib/CodeGen/ELFWriter.cpp')
| -rw-r--r-- | lib/CodeGen/ELFWriter.cpp | 903 |
1 files changed, 618 insertions, 285 deletions
diff --git a/lib/CodeGen/ELFWriter.cpp b/lib/CodeGen/ELFWriter.cpp index 9e91524..3e1ee11 100644 --- a/lib/CodeGen/ELFWriter.cpp +++ b/lib/CodeGen/ELFWriter.cpp @@ -29,7 +29,6 @@ //===----------------------------------------------------------------------===// #define DEBUG_TYPE "elfwriter" - #include "ELF.h" #include "ELFWriter.h" #include "ELFCodeEmitter.h" @@ -40,26 +39,33 @@ #include "llvm/CodeGen/BinaryObject.h" #include "llvm/CodeGen/FileWriters.h" #include "llvm/CodeGen/MachineCodeEmitter.h" +#include "llvm/CodeGen/ObjectCodeEmitter.h" +#include "llvm/CodeGen/MachineCodeEmitter.h" #include "llvm/CodeGen/MachineConstantPool.h" -#include "llvm/Target/TargetAsmInfo.h" +#include "llvm/MC/MCContext.h" +#include "llvm/MC/MCSectionELF.h" +#include "llvm/MC/MCAsmInfo.h" #include "llvm/Target/TargetData.h" #include "llvm/Target/TargetELFWriterInfo.h" +#include "llvm/Target/TargetLowering.h" +#include "llvm/Target/TargetLoweringObjectFile.h" #include "llvm/Target/TargetMachine.h" +#include "llvm/Support/Debug.h" +#include "llvm/Support/ErrorHandling.h" #include "llvm/Support/Mangler.h" -#include "llvm/Support/Streams.h" #include "llvm/Support/raw_ostream.h" -#include "llvm/Support/Debug.h" + using namespace llvm; char ELFWriter::ID = 0; -/// AddELFWriter - Concrete function to add the ELF writer to the function pass -/// manager. -MachineCodeEmitter *llvm::AddELFWriter(PassManagerBase &PM, - raw_ostream &O, - TargetMachine &TM) { + +/// AddELFWriter - Add the ELF writer to the function pass manager +ObjectCodeEmitter *llvm::AddELFWriter(PassManagerBase &PM, + raw_ostream &O, + TargetMachine &TM) { ELFWriter *EW = new ELFWriter(O, TM); PM.add(EW); - return &EW->getMachineCodeEmitter(); + return EW->getObjectCodeEmitter(); } //===----------------------------------------------------------------------===// @@ -68,27 +74,51 @@ MachineCodeEmitter *llvm::AddELFWriter(PassManagerBase &PM, ELFWriter::ELFWriter(raw_ostream &o, TargetMachine &tm) : MachineFunctionPass(&ID), O(o), TM(tm), + OutContext(*new MCContext()), + TLOF(TM.getTargetLowering()->getObjFileLowering()), is64Bit(TM.getTargetData()->getPointerSizeInBits() == 64), isLittleEndian(TM.getTargetData()->isLittleEndian()), ElfHdr(isLittleEndian, is64Bit) { - TAI = TM.getTargetAsmInfo(); + MAI = TM.getMCAsmInfo(); TEW = TM.getELFWriterInfo(); - // Create the machine code emitter object for this target. - MCE = new ELFCodeEmitter(*this); + // Create the object code emitter object for this target. + ElfCE = new ELFCodeEmitter(*this); // Inital number of sections NumSections = 0; } ELFWriter::~ELFWriter() { - delete MCE; + delete ElfCE; + delete &OutContext; + + while(!SymbolList.empty()) { + delete SymbolList.back(); + SymbolList.pop_back(); + } + + while(!PrivateSyms.empty()) { + delete PrivateSyms.back(); + PrivateSyms.pop_back(); + } + + while(!SectionList.empty()) { + delete SectionList.back(); + SectionList.pop_back(); + } + + // Release the name mangler object. + delete Mang; Mang = 0; } // doInitialization - Emit the file header and all of the global variables for // the module to the ELF file. bool ELFWriter::doInitialization(Module &M) { + // Initialize TargetLoweringObjectFile. + const_cast<TargetLoweringObjectFile&>(TLOF).Initialize(OutContext, TM); + Mang = new Mangler(M); // ELF Header @@ -138,13 +168,115 @@ bool ELFWriter::doInitialization(Module &M) { // Add the null section, which is required to be first in the file. getNullSection(); + // The first entry in the symtab is the null symbol and the second + // is a local symbol containing the module/file name + SymbolList.push_back(new ELFSym()); + SymbolList.push_back(ELFSym::getFileSym()); + return false; } +// AddPendingGlobalSymbol - Add a global to be processed and to +// the global symbol lookup, use a zero index because the table +// index will be determined later. +void ELFWriter::AddPendingGlobalSymbol(const GlobalValue *GV, + bool AddToLookup /* = false */) { + PendingGlobals.insert(GV); + if (AddToLookup) + GblSymLookup[GV] = 0; +} + +// AddPendingExternalSymbol - Add the external to be processed +// and to the external symbol lookup, use a zero index because +// the symbol table index will be determined later. +void ELFWriter::AddPendingExternalSymbol(const char *External) { + PendingExternals.insert(External); + ExtSymLookup[External] = 0; +} + +ELFSection &ELFWriter::getDataSection() { + const MCSectionELF *Data = (const MCSectionELF *)TLOF.getDataSection(); + return getSection(Data->getSectionName(), Data->getType(), + Data->getFlags(), 4); +} + +ELFSection &ELFWriter::getBSSSection() { + const MCSectionELF *BSS = (const MCSectionELF *)TLOF.getBSSSection(); + return getSection(BSS->getSectionName(), BSS->getType(), BSS->getFlags(), 4); +} + +// getCtorSection - Get the static constructor section +ELFSection &ELFWriter::getCtorSection() { + const MCSectionELF *Ctor = (const MCSectionELF *)TLOF.getStaticCtorSection(); + return getSection(Ctor->getSectionName(), Ctor->getType(), Ctor->getFlags()); +} + +// getDtorSection - Get the static destructor section +ELFSection &ELFWriter::getDtorSection() { + const MCSectionELF *Dtor = (const MCSectionELF *)TLOF.getStaticDtorSection(); + return getSection(Dtor->getSectionName(), Dtor->getType(), Dtor->getFlags()); +} + +// getTextSection - Get the text section for the specified function +ELFSection &ELFWriter::getTextSection(Function *F) { + const MCSectionELF *Text = + (const MCSectionELF *)TLOF.SectionForGlobal(F, Mang, TM); + return getSection(Text->getSectionName(), Text->getType(), Text->getFlags()); +} + +// getJumpTableSection - Get a read only section for constants when +// emitting jump tables. TODO: add PIC support +ELFSection &ELFWriter::getJumpTableSection() { + const MCSectionELF *JT = + (const MCSectionELF *)TLOF.getSectionForConstant(SectionKind::getReadOnly()); + return getSection(JT->getSectionName(), JT->getType(), JT->getFlags(), + TM.getTargetData()->getPointerABIAlignment()); +} + +// getConstantPoolSection - Get a constant pool section based on the machine +// constant pool entry type and relocation info. +ELFSection &ELFWriter::getConstantPoolSection(MachineConstantPoolEntry &CPE) { + SectionKind Kind; + switch (CPE.getRelocationInfo()) { + default: llvm_unreachable("Unknown section kind"); + case 2: Kind = SectionKind::getReadOnlyWithRel(); break; + case 1: + Kind = SectionKind::getReadOnlyWithRelLocal(); + break; + case 0: + switch (TM.getTargetData()->getTypeAllocSize(CPE.getType())) { + case 4: Kind = SectionKind::getMergeableConst4(); break; + case 8: Kind = SectionKind::getMergeableConst8(); break; + case 16: Kind = SectionKind::getMergeableConst16(); break; + default: Kind = SectionKind::getMergeableConst(); break; + } + } + + const MCSectionELF *CPSect = + (const MCSectionELF *)TLOF.getSectionForConstant(Kind); + return getSection(CPSect->getSectionName(), CPSect->getType(), + CPSect->getFlags(), CPE.getAlignment()); +} + +// getRelocSection - Return the relocation section of section 'S'. 'RelA' +// is true if the relocation section contains entries with addends. +ELFSection &ELFWriter::getRelocSection(ELFSection &S) { + unsigned SectionType = TEW->hasRelocationAddend() ? + ELFSection::SHT_RELA : ELFSection::SHT_REL; + + std::string SectionName(".rel"); + if (TEW->hasRelocationAddend()) + SectionName.append("a"); + SectionName.append(S.getName()); + + return getSection(SectionName, SectionType, 0, TEW->getPrefELFAlignment()); +} + +// getGlobalELFVisibility - Returns the ELF specific visibility type unsigned ELFWriter::getGlobalELFVisibility(const GlobalValue *GV) { switch (GV->getVisibility()) { default: - assert(0 && "unknown visibility type"); + llvm_unreachable("unknown visibility type"); case GlobalValue::DefaultVisibility: return ELFSym::STV_DEFAULT; case GlobalValue::HiddenVisibility: @@ -152,134 +284,132 @@ unsigned ELFWriter::getGlobalELFVisibility(const GlobalValue *GV) { case GlobalValue::ProtectedVisibility: return ELFSym::STV_PROTECTED; } - return 0; } -unsigned ELFWriter::getGlobalELFLinkage(const GlobalValue *GV) { +// getGlobalELFBinding - Returns the ELF specific binding type +unsigned ELFWriter::getGlobalELFBinding(const GlobalValue *GV) { if (GV->hasInternalLinkage()) return ELFSym::STB_LOCAL; - if (GV->hasWeakLinkage()) + if (GV->isWeakForLinker() && !GV->hasCommonLinkage()) return ELFSym::STB_WEAK; return ELFSym::STB_GLOBAL; } -// getElfSectionFlags - Get the ELF Section Header based on the -// flags defined in ELFTargetAsmInfo. -unsigned ELFWriter::getElfSectionFlags(unsigned Flags) { - unsigned ElfSectionFlags = ELFSection::SHF_ALLOC; - - if (Flags & SectionFlags::Code) - ElfSectionFlags |= ELFSection::SHF_EXECINSTR; - if (Flags & SectionFlags::Writeable) - ElfSectionFlags |= ELFSection::SHF_WRITE; - if (Flags & SectionFlags::Mergeable) - ElfSectionFlags |= ELFSection::SHF_MERGE; - if (Flags & SectionFlags::TLS) - ElfSectionFlags |= ELFSection::SHF_TLS; - if (Flags & SectionFlags::Strings) - ElfSectionFlags |= ELFSection::SHF_STRINGS; - - return ElfSectionFlags; -} - -// For global symbols without a section, return the Null section as a -// placeholder -ELFSection &ELFWriter::getGlobalSymELFSection(const GlobalVariable *GV, - ELFSym &Sym) { - // If this is a declaration, the symbol does not have a section. - if (!GV->hasInitializer()) { - Sym.SectionIdx = ELFSection::SHN_UNDEF; - return getNullSection(); - } +// getGlobalELFType - Returns the ELF specific type for a global +unsigned ELFWriter::getGlobalELFType(const GlobalValue *GV) { + if (GV->isDeclaration()) + return ELFSym::STT_NOTYPE; - // Get the name and flags of the section for the global - const Section *S = TAI->SectionForGlobal(GV); - unsigned SectionType = ELFSection::SHT_PROGBITS; - unsigned SectionFlags = getElfSectionFlags(S->getFlags()); - DOUT << "Section " << S->getName() << " for global " << GV->getName() << "\n"; + if (isa<Function>(GV)) + return ELFSym::STT_FUNC; - const TargetData *TD = TM.getTargetData(); - unsigned Align = TD->getPreferredAlignment(GV); - Constant *CV = GV->getInitializer(); - - // If this global has a zero initializer, go to .bss or common section. - // Variables are part of the common block if they are zero initialized - // and allowed to be merged with other symbols. - if (CV->isNullValue() || isa<UndefValue>(CV)) { - SectionType = ELFSection::SHT_NOBITS; - ELFSection &ElfS = getSection(S->getName(), SectionType, SectionFlags); - if (GV->hasLinkOnceLinkage() || GV->hasWeakLinkage() || - GV->hasCommonLinkage()) { - Sym.SectionIdx = ELFSection::SHN_COMMON; - Sym.IsCommon = true; - ElfS.Align = 1; - return ElfS; - } - Sym.IsBss = true; - Sym.SectionIdx = ElfS.SectionIdx; - if (Align) ElfS.Size = (ElfS.Size + Align-1) & ~(Align-1); - ElfS.Align = std::max(ElfS.Align, Align); - return ElfS; - } - - Sym.IsConstant = true; - ELFSection &ElfS = getSection(S->getName(), SectionType, SectionFlags); - Sym.SectionIdx = ElfS.SectionIdx; - ElfS.Align = std::max(ElfS.Align, Align); - return ElfS; + return ELFSym::STT_OBJECT; } -void ELFWriter::EmitFunctionDeclaration(const Function *F) { - ELFSym GblSym(F); - GblSym.setBind(ELFSym::STB_GLOBAL); - GblSym.setType(ELFSym::STT_NOTYPE); - GblSym.setVisibility(ELFSym::STV_DEFAULT); - GblSym.SectionIdx = ELFSection::SHN_UNDEF; - SymbolList.push_back(GblSym); +// IsELFUndefSym - True if the global value must be marked as a symbol +// which points to a SHN_UNDEF section. This means that the symbol has +// no definition on the module. +static bool IsELFUndefSym(const GlobalValue *GV) { + return GV->isDeclaration() || (isa<Function>(GV)); } -void ELFWriter::EmitGlobalVar(const GlobalVariable *GV) { - unsigned SymBind = getGlobalELFLinkage(GV); - unsigned Align=0, Size=0; - ELFSym GblSym(GV); - GblSym.setBind(SymBind); - GblSym.setVisibility(getGlobalELFVisibility(GV)); - - if (GV->hasInitializer()) { - GblSym.setType(ELFSym::STT_OBJECT); - const TargetData *TD = TM.getTargetData(); - Align = TD->getPreferredAlignment(GV); - Size = TD->getTypeAllocSize(GV->getInitializer()->getType()); - GblSym.Size = Size; +// AddToSymbolList - Update the symbol lookup and If the symbol is +// private add it to PrivateSyms list, otherwise to SymbolList. +void ELFWriter::AddToSymbolList(ELFSym *GblSym) { + assert(GblSym->isGlobalValue() && "Symbol must be a global value"); + + const GlobalValue *GV = GblSym->getGlobalValue(); + if (GV->hasPrivateLinkage()) { + // For a private symbols, keep track of the index inside + // the private list since it will never go to the symbol + // table and won't be patched up later. + PrivateSyms.push_back(GblSym); + GblSymLookup[GV] = PrivateSyms.size()-1; } else { - GblSym.setType(ELFSym::STT_NOTYPE); + // Non private symbol are left with zero indices until + // they are patched up during the symbol table emition + // (where the indicies are created). + SymbolList.push_back(GblSym); + GblSymLookup[GV] = 0; } +} - ELFSection &GblSection = getGlobalSymELFSection(GV, GblSym); - - if (GblSym.IsCommon) { - GblSym.Value = Align; - } else if (GblSym.IsBss) { - GblSym.Value = GblSection.Size; - GblSection.Size += Size; - } else if (GblSym.IsConstant){ - // GblSym.Value should contain the symbol index inside the section, - // and all symbols should start on their required alignment boundary - GblSym.Value = (GblSection.size() + (Align-1)) & (-Align); - GblSection.emitAlignment(Align); - EmitGlobalConstant(GV->getInitializer(), GblSection); - } +// EmitGlobal - Choose the right section for global and emit it +void ELFWriter::EmitGlobal(const GlobalValue *GV) { - // Local symbols should come first on the symbol table. - if (!GV->hasPrivateLinkage()) { - if (SymBind == ELFSym::STB_LOCAL) - SymbolList.push_front(GblSym); - else - SymbolList.push_back(GblSym); + // Check if the referenced symbol is already emitted + if (GblSymLookup.find(GV) != GblSymLookup.end()) + return; + + // Handle ELF Bind, Visibility and Type for the current symbol + unsigned SymBind = getGlobalELFBinding(GV); + unsigned SymType = getGlobalELFType(GV); + bool IsUndefSym = IsELFUndefSym(GV); + + ELFSym *GblSym = IsUndefSym ? ELFSym::getUndefGV(GV, SymBind) + : ELFSym::getGV(GV, SymBind, SymType, getGlobalELFVisibility(GV)); + + if (!IsUndefSym) { + assert(isa<GlobalVariable>(GV) && "GV not a global variable!"); + const GlobalVariable *GVar = dyn_cast<GlobalVariable>(GV); + + // Handle special llvm globals + if (EmitSpecialLLVMGlobal(GVar)) + return; + + // Get the ELF section where this global belongs from TLOF + const MCSectionELF *S = + (const MCSectionELF *)TLOF.SectionForGlobal(GV, Mang, TM); + ELFSection &ES = + getSection(S->getSectionName(), S->getType(), S->getFlags()); + SectionKind Kind = S->getKind(); + + // The symbol align should update the section alignment if needed + const TargetData *TD = TM.getTargetData(); + unsigned Align = TD->getPreferredAlignment(GVar); + unsigned Size = TD->getTypeAllocSize(GVar->getInitializer()->getType()); + GblSym->Size = Size; + + if (S->HasCommonSymbols()) { // Symbol must go to a common section + GblSym->SectionIdx = ELFSection::SHN_COMMON; + + // A new linkonce section is created for each global in the + // common section, the default alignment is 1 and the symbol + // value contains its alignment. + ES.Align = 1; + GblSym->Value = Align; + + } else if (Kind.isBSS() || Kind.isThreadBSS()) { // Symbol goes to BSS. + GblSym->SectionIdx = ES.SectionIdx; + + // Update the size with alignment and the next object can + // start in the right offset in the section + if (Align) ES.Size = (ES.Size + Align-1) & ~(Align-1); + ES.Align = std::max(ES.Align, Align); + + // GblSym->Value should contain the virtual offset inside the section. + // Virtual because the BSS space is not allocated on ELF objects + GblSym->Value = ES.Size; + ES.Size += Size; + + } else { // The symbol must go to some kind of data section + GblSym->SectionIdx = ES.SectionIdx; + + // GblSym->Value should contain the symbol offset inside the section, + // and all symbols should start on their required alignment boundary + ES.Align = std::max(ES.Align, Align); + ES.emitAlignment(Align); + GblSym->Value = ES.size(); + + // Emit the global to the data section 'ES' + EmitGlobalConstant(GVar->getInitializer(), ES); + } } + + AddToSymbolList(GblSym); } void ELFWriter::EmitGlobalConstantStruct(const ConstantStruct *CVS, @@ -305,8 +435,7 @@ void ELFWriter::EmitGlobalConstantStruct(const ConstantStruct *CVS, // Insert padding - this may include padding to increase the size of the // current field up to the ABI size (if the struct is not packed) as well // as padding to ensure that the next field starts at the right offset. - for (unsigned p=0; p < padSize; p++) - GblS.emitByte(0); + GblS.emitZeros(padSize); } assert(sizeSoFar == cvsLayout->getSizeInBytes() && "Layout of constant struct may be incorrect!"); @@ -317,65 +446,242 @@ void ELFWriter::EmitGlobalConstant(const Constant *CV, ELFSection &GblS) { unsigned Size = TD->getTypeAllocSize(CV->getType()); if (const ConstantArray *CVA = dyn_cast<ConstantArray>(CV)) { - if (CVA->isString()) { - std::string GblStr = CVA->getAsString(); - GblStr.resize(GblStr.size()-1); - GblS.emitString(GblStr); - } else { // Not a string. Print the values in successive locations - for (unsigned i = 0, e = CVA->getNumOperands(); i != e; ++i) - EmitGlobalConstant(CVA->getOperand(i), GblS); - } + for (unsigned i = 0, e = CVA->getNumOperands(); i != e; ++i) + EmitGlobalConstant(CVA->getOperand(i), GblS); + return; + } else if (isa<ConstantAggregateZero>(CV)) { + GblS.emitZeros(Size); return; } else if (const ConstantStruct *CVS = dyn_cast<ConstantStruct>(CV)) { EmitGlobalConstantStruct(CVS, GblS); return; } else if (const ConstantFP *CFP = dyn_cast<ConstantFP>(CV)) { - uint64_t Val = CFP->getValueAPF().bitcastToAPInt().getZExtValue(); - if (CFP->getType() == Type::DoubleTy) - GblS.emitWord64(Val); - else if (CFP->getType() == Type::FloatTy) - GblS.emitWord32(Val); - else if (CFP->getType() == Type::X86_FP80Ty) { - assert(0 && "X86_FP80Ty global emission not implemented"); - } else if (CFP->getType() == Type::PPC_FP128Ty) - assert(0 && "PPC_FP128Ty global emission not implemented"); + APInt Val = CFP->getValueAPF().bitcastToAPInt(); + if (CFP->getType()->isDoubleTy()) + GblS.emitWord64(Val.getZExtValue()); + else if (CFP->getType()->isFloatTy()) + GblS.emitWord32(Val.getZExtValue()); + else if (CFP->getType()->isX86_FP80Ty()) { + unsigned PadSize = TD->getTypeAllocSize(CFP->getType())- + TD->getTypeStoreSize(CFP->getType()); + GblS.emitWordFP80(Val.getRawData(), PadSize); + } else if (CFP->getType()->isPPC_FP128Ty()) + llvm_unreachable("PPC_FP128Ty global emission not implemented"); return; } else if (const ConstantInt *CI = dyn_cast<ConstantInt>(CV)) { - if (Size == 4) + if (Size == 1) + GblS.emitByte(CI->getZExtValue()); + else if (Size == 2) + GblS.emitWord16(CI->getZExtValue()); + else if (Size == 4) GblS.emitWord32(CI->getZExtValue()); - else if (Size == 8) - GblS.emitWord64(CI->getZExtValue()); - else - assert(0 && "LargeInt global emission not implemented"); + else + EmitGlobalConstantLargeInt(CI, GblS); return; } else if (const ConstantVector *CP = dyn_cast<ConstantVector>(CV)) { const VectorType *PTy = CP->getType(); for (unsigned I = 0, E = PTy->getNumElements(); I < E; ++I) EmitGlobalConstant(CP->getOperand(I), GblS); return; + } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(CV)) { + // Resolve a constant expression which returns a (Constant, Offset) + // pair. If 'Res.first' is a GlobalValue, emit a relocation with + // the offset 'Res.second', otherwise emit a global constant like + // it is always done for not contant expression types. + CstExprResTy Res = ResolveConstantExpr(CE); + const Constant *Op = Res.first; + + if (isa<GlobalValue>(Op)) + EmitGlobalDataRelocation(cast<const GlobalValue>(Op), + TD->getTypeAllocSize(Op->getType()), + GblS, Res.second); + else + EmitGlobalConstant(Op, GblS); + + return; + } else if (CV->getType()->getTypeID() == Type::PointerTyID) { + // Fill the data entry with zeros or emit a relocation entry + if (isa<ConstantPointerNull>(CV)) + GblS.emitZeros(Size); + else + EmitGlobalDataRelocation(cast<const GlobalValue>(CV), + Size, GblS); + return; + } else if (const GlobalValue *GV = dyn_cast<GlobalValue>(CV)) { + // This is a constant address for a global variable or function and + // therefore must be referenced using a relocation entry. + EmitGlobalDataRelocation(GV, Size, GblS); + return; + } + + std::string msg; + raw_string_ostream ErrorMsg(msg); + ErrorMsg << "Constant unimp for type: " << *CV->getType(); + llvm_report_error(ErrorMsg.str()); +} + +// ResolveConstantExpr - Resolve the constant expression until it stop +// yielding other constant expressions. +CstExprResTy ELFWriter::ResolveConstantExpr(const Constant *CV) { + const TargetData *TD = TM.getTargetData(); + + // There ins't constant expression inside others anymore + if (!isa<ConstantExpr>(CV)) + return std::make_pair(CV, 0); + + const ConstantExpr *CE = dyn_cast<ConstantExpr>(CV); + switch (CE->getOpcode()) { + case Instruction::BitCast: + return ResolveConstantExpr(CE->getOperand(0)); + + case Instruction::GetElementPtr: { + const Constant *ptrVal = CE->getOperand(0); + SmallVector<Value*, 8> idxVec(CE->op_begin()+1, CE->op_end()); + int64_t Offset = TD->getIndexedOffset(ptrVal->getType(), &idxVec[0], + idxVec.size()); + return std::make_pair(ptrVal, Offset); + } + case Instruction::IntToPtr: { + Constant *Op = CE->getOperand(0); + Op = ConstantExpr::getIntegerCast(Op, TD->getIntPtrType(CV->getContext()), + false/*ZExt*/); + return ResolveConstantExpr(Op); + } + case Instruction::PtrToInt: { + Constant *Op = CE->getOperand(0); + const Type *Ty = CE->getType(); + + // We can emit the pointer value into this slot if the slot is an + // integer slot greater or equal to the size of the pointer. + if (TD->getTypeAllocSize(Ty) == TD->getTypeAllocSize(Op->getType())) + return ResolveConstantExpr(Op); + + llvm_unreachable("Integer size less then pointer size"); + } + case Instruction::Add: + case Instruction::Sub: { + // Only handle cases where there's a constant expression with GlobalValue + // as first operand and ConstantInt as second, which are the cases we can + // solve direclty using a relocation entry. GlobalValue=Op0, CstInt=Op1 + // 1) Instruction::Add => (global) + CstInt + // 2) Instruction::Sub => (global) + -CstInt + const Constant *Op0 = CE->getOperand(0); + const Constant *Op1 = CE->getOperand(1); + assert(isa<ConstantInt>(Op1) && "Op1 must be a ConstantInt"); + + CstExprResTy Res = ResolveConstantExpr(Op0); + assert(isa<GlobalValue>(Res.first) && "Op0 must be a GlobalValue"); + + const APInt &RHS = cast<ConstantInt>(Op1)->getValue(); + switch (CE->getOpcode()) { + case Instruction::Add: + return std::make_pair(Res.first, RHS.getSExtValue()); + case Instruction::Sub: + return std::make_pair(Res.first, (-RHS).getSExtValue()); + } + } + } + + std::string msg(CE->getOpcodeName()); + raw_string_ostream ErrorMsg(msg); + ErrorMsg << ": Unsupported ConstantExpr type"; + llvm_report_error(ErrorMsg.str()); + + return std::make_pair(CV, 0); // silence warning +} + +void ELFWriter::EmitGlobalDataRelocation(const GlobalValue *GV, unsigned Size, + ELFSection &GblS, int64_t Offset) { + // Create the relocation entry for the global value + MachineRelocation MR = + MachineRelocation::getGV(GblS.getCurrentPCOffset(), + TEW->getAbsoluteLabelMachineRelTy(), + const_cast<GlobalValue*>(GV), + Offset); + + // Fill the data entry with zeros + GblS.emitZeros(Size); + + // Add the relocation entry for the current data section + GblS.addRelocation(MR); +} + +void ELFWriter::EmitGlobalConstantLargeInt(const ConstantInt *CI, + ELFSection &S) { + const TargetData *TD = TM.getTargetData(); + unsigned BitWidth = CI->getBitWidth(); + assert(isPowerOf2_32(BitWidth) && + "Non-power-of-2-sized integers not handled!"); + + const uint64_t *RawData = CI->getValue().getRawData(); + uint64_t Val = 0; + for (unsigned i = 0, e = BitWidth / 64; i != e; ++i) { + Val = (TD->isBigEndian()) ? RawData[e - i - 1] : RawData[i]; + S.emitWord64(Val); } - assert(0 && "unknown global constant"); } +/// EmitSpecialLLVMGlobal - Check to see if the specified global is a +/// special global used by LLVM. If so, emit it and return true, otherwise +/// do nothing and return false. +bool ELFWriter::EmitSpecialLLVMGlobal(const GlobalVariable *GV) { + if (GV->getName() == "llvm.used") + llvm_unreachable("not implemented yet"); + + // Ignore debug and non-emitted data. This handles llvm.compiler.used. + if (GV->getSection() == "llvm.metadata" || + GV->hasAvailableExternallyLinkage()) + return true; + + if (!GV->hasAppendingLinkage()) return false; + + assert(GV->hasInitializer() && "Not a special LLVM global!"); + + const TargetData *TD = TM.getTargetData(); + unsigned Align = TD->getPointerPrefAlignment(); + if (GV->getName() == "llvm.global_ctors") { + ELFSection &Ctor = getCtorSection(); + Ctor.emitAlignment(Align); + EmitXXStructorList(GV->getInitializer(), Ctor); + return true; + } + + if (GV->getName() == "llvm.global_dtors") { + ELFSection &Dtor = getDtorSection(); + Dtor.emitAlignment(Align); + EmitXXStructorList(GV->getInitializer(), Dtor); + return true; + } + + return false; +} + +/// EmitXXStructorList - Emit the ctor or dtor list. This just emits out the +/// function pointers, ignoring the init priority. +void ELFWriter::EmitXXStructorList(Constant *List, ELFSection &Xtor) { + // Should be an array of '{ int, void ()* }' structs. The first value is the + // init priority, which we ignore. + if (!isa<ConstantArray>(List)) return; + ConstantArray *InitList = cast<ConstantArray>(List); + for (unsigned i = 0, e = InitList->getNumOperands(); i != e; ++i) + if (ConstantStruct *CS = dyn_cast<ConstantStruct>(InitList->getOperand(i))){ + if (CS->getNumOperands() != 2) return; // Not array of 2-element structs. + + if (CS->getOperand(1)->isNullValue()) + return; // Found a null terminator, exit printing. + // Emit the function pointer. + EmitGlobalConstant(CS->getOperand(1), Xtor); + } +} bool ELFWriter::runOnMachineFunction(MachineFunction &MF) { - // Nothing to do here, this is all done through the MCE object above. + // Nothing to do here, this is all done through the ElfCE object above. return false; } /// doFinalization - Now that the module has been completely processed, emit /// the ELF file to 'O'. bool ELFWriter::doFinalization(Module &M) { - /// FIXME: This should be removed when moving to ObjectCodeEmiter. Since the - /// current ELFCodeEmiter uses CurrBuff, ... it doesn't update S.Data - /// vector size for .text sections, so this is a quick dirty fix - ELFSection &TS = getTextSection(); - if (TS.Size) { - BinaryData &BD = TS.getData(); - for (unsigned e=0; e<TS.Size; ++e) - BD.push_back(BD[e]); - } - // Emit .data section placeholder getDataSection(); @@ -384,57 +690,34 @@ bool ELFWriter::doFinalization(Module &M) { // Build and emit data, bss and "common" sections. for (Module::global_iterator I = M.global_begin(), E = M.global_end(); - I != E; ++I) { - EmitGlobalVar(I); - GblSymLookup[I] = 0; - } + I != E; ++I) + EmitGlobal(I); // Emit all pending globals - // TODO: this should be done only for referenced symbols - for (SetVector<GlobalValue*>::const_iterator I = PendingGlobals.begin(), - E = PendingGlobals.end(); I != E; ++I) { + for (PendingGblsIter I = PendingGlobals.begin(), E = PendingGlobals.end(); + I != E; ++I) + EmitGlobal(*I); - // No need to emit the symbol again - if (GblSymLookup.find(*I) != GblSymLookup.end()) - continue; - - if (GlobalVariable *GV = dyn_cast<GlobalVariable>(*I)) { - EmitGlobalVar(GV); - } else if (Function *F = dyn_cast<Function>(*I)) { - // If function is not in GblSymLookup, it doesn't have a body, - // so emit the symbol as a function declaration (no section associated) - EmitFunctionDeclaration(F); - } else { - assert("unknown howto handle pending global"); - } - GblSymLookup[*I] = 0; - } + // Emit all pending externals + for (PendingExtsIter I = PendingExternals.begin(), E = PendingExternals.end(); + I != E; ++I) + SymbolList.push_back(ELFSym::getExtSym(*I)); // Emit non-executable stack note - if (TAI->getNonexecutableStackDirective()) + if (MAI->getNonexecutableStackDirective()) getNonExecStackSection(); - // Emit a symbol for each section created until now - for (std::map<std::string, ELFSection*>::iterator I = SectionLookup.begin(), - E = SectionLookup.end(); I != E; ++I) { - ELFSection *ES = I->second; - - // Skip null section - if (ES->SectionIdx == 0) continue; - - ELFSym SectionSym(0); - SectionSym.SectionIdx = ES->SectionIdx; - SectionSym.Size = 0; - SectionSym.setBind(ELFSym::STB_LOCAL); - SectionSym.setType(ELFSym::STT_SECTION); - SectionSym.setVisibility(ELFSym::STV_DEFAULT); - - // Local symbols go in the list front - SymbolList.push_front(SectionSym); + // Emit a symbol for each section created until now, skip null section + for (unsigned i = 1, e = SectionList.size(); i < e; ++i) { + ELFSection &ES = *SectionList[i]; + ELFSym *SectionSym = ELFSym::getSectionSym(); + SectionSym->SectionIdx = ES.SectionIdx; + SymbolList.push_back(SectionSym); + ES.Sym = SymbolList.back(); } // Emit string table - EmitStringTable(); + EmitStringTable(M.getModuleIdentifier()); // Emit the symbol table now, if non-empty. EmitSymbolTable(); @@ -448,77 +731,106 @@ bool ELFWriter::doFinalization(Module &M) { // Dump the sections and section table to the .o file. OutputSectionsAndSectionTable(); - // We are done with the abstract symbols. - SectionList.clear(); - NumSections = 0; - - // Release the name mangler object. - delete Mang; Mang = 0; return false; } +// RelocateField - Patch relocatable field with 'Offset' in 'BO' +// using a 'Value' of known 'Size' +void ELFWriter::RelocateField(BinaryObject &BO, uint32_t Offset, + int64_t Value, unsigned Size) { + if (Size == 32) + BO.fixWord32(Value, Offset); + else if (Size == 64) + BO.fixWord64(Value, Offset); + else + llvm_unreachable("don't know howto patch relocatable field"); +} + /// EmitRelocations - Emit relocations void ELFWriter::EmitRelocations() { + // True if the target uses the relocation entry to hold the addend, + // otherwise the addend is written directly to the relocatable field. + bool HasRelA = TEW->hasRelocationAddend(); + // Create Relocation sections for each section which needs it. - for (std::list<ELFSection>::iterator I = SectionList.begin(), - E = SectionList.end(); I != E; ++I) { + for (unsigned i=0, e=SectionList.size(); i != e; ++i) { + ELFSection &S = *SectionList[i]; // This section does not have relocations - if (!I->hasRelocations()) continue; - - // Get the relocation section for section 'I' - bool HasRelA = TEW->hasRelocationAddend(); - ELFSection &RelSec = getRelocSection(I->getName(), HasRelA, - TEW->getPrefELFAlignment()); + if (!S.hasRelocations()) continue; + ELFSection &RelSec = getRelocSection(S); // 'Link' - Section hdr idx of the associated symbol table // 'Info' - Section hdr idx of the section to which the relocation applies ELFSection &SymTab = getSymbolTableSection(); RelSec.Link = SymTab.SectionIdx; - RelSec.Info = I->SectionIdx; + RelSec.Info = S.SectionIdx; RelSec.EntSize = TEW->getRelocationEntrySize(); // Get the relocations from Section - std::vector<MachineRelocation> Relos = I->getRelocations(); + std::vector<MachineRelocation> Relos = S.getRelocations(); for (std::vector<MachineRelocation>::iterator MRI = Relos.begin(), MRE = Relos.end(); MRI != MRE; ++MRI) { MachineRelocation &MR = *MRI; - // Offset from the start of the section containing the symbol - unsigned Offset = MR.getMachineCodeOffset(); + // Relocatable field offset from the section start + unsigned RelOffset = MR.getMachineCodeOffset(); // Symbol index in the symbol table unsigned SymIdx = 0; - // Target specific ELF relocation type + // Target specific relocation field type and size unsigned RelType = TEW->getRelocationType(MR.getRelocationType()); - - // Constant addend used to compute the value to be stored - // into the relocatable field + unsigned RelTySize = TEW->getRelocationTySize(RelType); int64_t Addend = 0; // There are several machine relocations types, and each one of // them needs a different approach to retrieve the symbol table index. if (MR.isGlobalValue()) { const GlobalValue *G = MR.getGlobalValue(); + int64_t GlobalOffset = MR.getConstantVal(); SymIdx = GblSymLookup[G]; - Addend = TEW->getAddendForRelTy(RelType); + if (G->hasPrivateLinkage()) { + // If the target uses a section offset in the relocation: + // SymIdx + Addend = section sym for global + section offset + unsigned SectionIdx = PrivateSyms[SymIdx]->SectionIdx; + Addend = PrivateSyms[SymIdx]->Value + GlobalOffset; + SymIdx = SectionList[SectionIdx]->getSymbolTableIndex(); + } else { + Addend = TEW->getDefaultAddendForRelTy(RelType, GlobalOffset); + } + } else if (MR.isExternalSymbol()) { + const char *ExtSym = MR.getExternalSymbol(); + SymIdx = ExtSymLookup[ExtSym]; + Addend = TEW->getDefaultAddendForRelTy(RelType); } else { + // Get the symbol index for the section symbol unsigned SectionIdx = MR.getConstantVal(); - // TODO: use a map for this. - for (std::list<ELFSym>::iterator I = SymbolList.begin(), - E = SymbolList.end(); I != E; ++I) - if ((SectionIdx == I->SectionIdx) && - (I->getType() == ELFSym::STT_SECTION)) { - SymIdx = I->SymTabIdx; - break; - } - Addend = (uint64_t)MR.getResultPointer(); + SymIdx = SectionList[SectionIdx]->getSymbolTableIndex(); + + // The symbol offset inside the section + int64_t SymOffset = (int64_t)MR.getResultPointer(); + + // For pc relative relocations where symbols are defined in the same + // section they are referenced, ignore the relocation entry and patch + // the relocatable field with the symbol offset directly. + if (S.SectionIdx == SectionIdx && TEW->isPCRelativeRel(RelType)) { + int64_t Value = TEW->computeRelocation(SymOffset, RelOffset, RelType); + RelocateField(S, RelOffset, Value, RelTySize); + continue; + } + + Addend = TEW->getDefaultAddendForRelTy(RelType, SymOffset); } + // The target without addend on the relocation symbol must be + // patched in the relocation place itself to contain the addend + // otherwise write zeros to make sure there is no garbage there + RelocateField(S, RelOffset, HasRelA ? 0 : Addend, RelTySize); + // Get the relocation entry and emit to the relocation section - ELFRelocation Rel(Offset, SymIdx, RelType, HasRelA, Addend); + ELFRelocation Rel(RelOffset, SymIdx, RelType, HasRelA, Addend); EmitRelocation(RelSec, Rel, HasRelA); } } @@ -554,7 +866,7 @@ void ELFWriter::EmitSymbol(BinaryObject &SymbolTable, ELFSym &Sym) { /// EmitSectionHeader - Write section 'Section' header in 'SHdrTab' /// Section Header Table -void ELFWriter::EmitSectionHeader(BinaryObject &SHdrTab, +void ELFWriter::EmitSectionHeader(BinaryObject &SHdrTab, const ELFSection &SHdr) { SHdrTab.emitWord32(SHdr.NameIdx); SHdrTab.emitWord32(SHdr.Type); @@ -581,27 +893,30 @@ void ELFWriter::EmitSectionHeader(BinaryObject &SHdrTab, /// EmitStringTable - If the current symbol table is non-empty, emit the string /// table for it -void ELFWriter::EmitStringTable() { +void ELFWriter::EmitStringTable(const std::string &ModuleName) { if (!SymbolList.size()) return; // Empty symbol table. ELFSection &StrTab = getStringTableSection(); // Set the zero'th symbol to a null byte, as required. StrTab.emitByte(0); - // Walk on the symbol list and write symbol names into the - // string table. + // Walk on the symbol list and write symbol names into the string table. unsigned Index = 1; - for (std::list<ELFSym>::iterator I = SymbolList.begin(), - E = SymbolList.end(); I != E; ++I) { + for (ELFSymIter I=SymbolList.begin(), E=SymbolList.end(); I != E; ++I) { + ELFSym &Sym = *(*I); - // Use the name mangler to uniquify the LLVM symbol. std::string Name; - if (I->GV) Name.append(Mang->getValueName(I->GV)); + if (Sym.isGlobalValue()) + Name.append(Mang->getMangledName(Sym.getGlobalValue())); + else if (Sym.isExternalSym()) + Name.append(Sym.getExternalSymbol()); + else if (Sym.isFileType()) + Name.append(ModuleName); if (Name.empty()) { - I->NameIdx = 0; + Sym.NameIdx = 0; } else { - I->NameIdx = Index; + Sym.NameIdx = Index; StrTab.emitString(Name); // Keep track of the number of bytes emitted to this section. @@ -612,11 +927,38 @@ void ELFWriter::EmitStringTable() { StrTab.Size = Index; } +// SortSymbols - On the symbol table local symbols must come before +// all other symbols with non-local bindings. The return value is +// the position of the first non local symbol. +unsigned ELFWriter::SortSymbols() { + unsigned FirstNonLocalSymbol; + std::vector<ELFSym*> LocalSyms, OtherSyms; + + for (ELFSymIter I=SymbolList.begin(), E=SymbolList.end(); I != E; ++I) { + if ((*I)->isLocalBind()) + LocalSyms.push_back(*I); + else + OtherSyms.push_back(*I); + } + SymbolList.clear(); + FirstNonLocalSymbol = LocalSyms.size(); + + for (unsigned i = 0; i < FirstNonLocalSymbol; ++i) + SymbolList.push_back(LocalSyms[i]); + + for (ELFSymIter I=OtherSyms.begin(), E=OtherSyms.end(); I != E; ++I) + SymbolList.push_back(*I); + + LocalSyms.clear(); + OtherSyms.clear(); + + return FirstNonLocalSymbol; +} + /// EmitSymbolTable - Emit the symbol table itself. void ELFWriter::EmitSymbolTable() { if (!SymbolList.size()) return; // Empty symbol table. - unsigned FirstNonLocalSymbol = 1; // Now that we have emitted the string table and know the offset into the // string table of each symbol, emit the symbol table itself. ELFSection &SymTab = getSymbolTableSection(); @@ -628,30 +970,27 @@ void ELFWriter::EmitSymbolTable() { // Size of each symtab entry. SymTab.EntSize = TEW->getSymTabEntrySize(); - // The first entry in the symtab is the null symbol - ELFSym NullSym = ELFSym(0); - EmitSymbol(SymTab, NullSym); + // Reorder the symbol table with local symbols first! + unsigned FirstNonLocalSymbol = SortSymbols(); - // Emit all the symbols to the symbol table. Skip the null - // symbol, cause it's emitted already - unsigned Index = 1; - for (std::list<ELFSym>::iterator I = SymbolList.begin(), - E = SymbolList.end(); I != E; ++I, ++Index) { - // Keep track of the first non-local symbol - if (I->getBind() == ELFSym::STB_LOCAL) - FirstNonLocalSymbol++; + // Emit all the symbols to the symbol table. + for (unsigned i = 0, e = SymbolList.size(); i < e; ++i) { + ELFSym &Sym = *SymbolList[i]; // Emit symbol to the symbol table - EmitSymbol(SymTab, *I); + EmitSymbol(SymTab, Sym); - // Record the symbol table index for each global value - if (I->GV) - GblSymLookup[I->GV] = Index; + // Record the symbol table index for each symbol + if (Sym.isGlobalValue()) + GblSymLookup[Sym.getGlobalValue()] = i; + else if (Sym.isExternalSym()) + ExtSymLookup[Sym.getExternalSymbol()] = i; // Keep track on the symbol index into the symbol table - I->SymTabIdx = Index; + Sym.SymTabIdx = i; } + // One greater than the symbol table index of the last local symbol SymTab.Info = FirstNonLocalSymbol; SymTab.Size = SymTab.size(); } @@ -671,15 +1010,15 @@ void ELFWriter::EmitSectionTableStringTable() { // the string table. unsigned Index = 0; - for (std::list<ELFSection>::iterator I = SectionList.begin(), - E = SectionList.end(); I != E; ++I) { + for (ELFSectionIter I=SectionList.begin(), E=SectionList.end(); I != E; ++I) { + ELFSection &S = *(*I); // Set the index into the table. Note if we have lots of entries with // common suffixes, we could memoize them here if we cared. - I->NameIdx = Index; - SHStrTab.emitString(I->getName()); + S.NameIdx = Index; + SHStrTab.emitString(S.getName()); // Keep track of the number of bytes emitted to this section. - Index += I->getName().size()+1; + Index += S.getName().size()+1; } // Set the size of .shstrtab now that we know what it is. @@ -694,29 +1033,24 @@ void ELFWriter::OutputSectionsAndSectionTable() { // Pass #1: Compute the file offset for each section. size_t FileOff = ElfHdr.size(); // File header first. - // Adjust alignment of all section if needed. - for (std::list<ELFSection>::iterator I = SectionList.begin(), - E = SectionList.end(); I != E; ++I) { - - // Section idx 0 has 0 offset - if (!I->SectionIdx) - continue; - - if (!I->size()) { - I->Offset = FileOff; + // Adjust alignment of all section if needed, skip the null section. + for (unsigned i=1, e=SectionList.size(); i < e; ++i) { + ELFSection &ES = *SectionList[i]; + if (!ES.size()) { + ES.Offset = FileOff; continue; } // Update Section size - if (!I->Size) - I->Size = I->size(); + if (!ES.Size) + ES.Size = ES.size(); // Align FileOff to whatever the alignment restrictions of the section are. - if (I->Align) - FileOff = (FileOff+I->Align-1) & ~(I->Align-1); + if (ES.Align) + FileOff = (FileOff+ES.Align-1) & ~(ES.Align-1); - I->Offset = FileOff; - FileOff += I->Size; + ES.Offset = FileOff; + FileOff += ES.Size; } // Align Section Header. @@ -740,11 +1074,11 @@ void ELFWriter::OutputSectionsAndSectionTable() { BinaryObject SHdrTable(isLittleEndian, is64Bit); // Emit all of sections to the file and build the section header table. - while (!SectionList.empty()) { - ELFSection &S = *SectionList.begin(); - DOUT << "SectionIdx: " << S.SectionIdx << ", Name: " << S.getName() - << ", Size: " << S.Size << ", Offset: " << S.Offset - << ", SectionData Size: " << S.size() << "\n"; + for (ELFSectionIter I=SectionList.begin(), E=SectionList.end(); I != E; ++I) { + ELFSection &S = *(*I); + DEBUG(errs() << "SectionIdx: " << S.SectionIdx << ", Name: " << S.getName() + << ", Size: " << S.Size << ", Offset: " << S.Offset + << ", SectionData Size: " << S.size() << "\n"); // Align FileOff to whatever the alignment restrictions of the section are. if (S.size()) { @@ -758,7 +1092,6 @@ void ELFWriter::OutputSectionsAndSectionTable() { } EmitSectionHeader(SHdrTable, S); - SectionList.pop_front(); } // Align output for the section table. |
