//===----------------------------------------------------------------------===//
#define DEBUG_TYPE "elfwriter"
-
#include "ELF.h"
#include "ELFWriter.h"
#include "ELFCodeEmitter.h"
#include "llvm/CodeGen/ObjectCodeEmitter.h"
#include "llvm/CodeGen/MachineCodeEmitter.h"
#include "llvm/CodeGen/MachineConstantPool.h"
+#include "llvm/MC/MCContext.h"
+#include "llvm/MC/MCSectionELF.h"
#include "llvm/Target/TargetAsmInfo.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/Mangler.h"
#include "llvm/Support/Streams.h"
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) {
ELFWriter::~ELFWriter() {
delete ElfCE;
+ delete &OutContext;
}
// 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
// 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;
}
-// Get jump table section on the section name returned by TAI
+// 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() {
- unsigned Align = TM.getTargetData()->getPointerABIAlignment();
- return getSection(TAI->getJumpTableDataSection(),
- ELFSection::SHT_PROGBITS,
- ELFSection::SHF_ALLOC, Align);
+ const MCSectionELF *JT =
+ (const MCSectionELF *)TLOF.getSectionForConstant(SectionKind::getReadOnly());
+ return getSection(JT->getSectionName(), JT->getType(), JT->getFlags(),
+ TM.getTargetData()->getPointerABIAlignment());
}
-// Get a constant pool section based on the section name returned by TAI
+// getConstantPoolSection - Get a constant pool section based on the machine
+// constant pool entry type and relocation info.
ELFSection &ELFWriter::getConstantPoolSection(MachineConstantPoolEntry &CPE) {
- std::string CstPoolName =
- TAI->SelectSectionForMachineConst(CPE.getType())->getName();
- return getSection(CstPoolName,
- ELFSection::SHT_PROGBITS,
- ELFSection::SHF_MERGE | ELFSection::SHF_ALLOC,
- CPE.getAlignment());
+ 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());
}
-// Return the relocation section of section 'S'. 'RelA' is true
-// if the relocation section contains entries with addends.
+// 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 SectionHeaderTy = TEW->hasRelocationAddend() ?
- ELFSection::SHT_RELA : ELFSection::SHT_REL;
- std::string RelSName(".rel");
+ unsigned SectionType = TEW->hasRelocationAddend() ?
+ ELFSection::SHT_RELA : ELFSection::SHT_REL;
+
+ std::string SectionName(".rel");
if (TEW->hasRelocationAddend())
- RelSName.append("a");
- RelSName.append(S.getName());
+ SectionName.append("a");
+ SectionName.append(S.getName());
- return getSection(RelSName, SectionHeaderTy, 0, TEW->getPrefELFAlignment());
+ return getSection(SectionName, SectionType, 0, TEW->getPrefELFAlignment());
}
// getGlobalELFVisibility - Returns the ELF specific visibility type
if (GV->hasInternalLinkage())
return ELFSym::STB_LOCAL;
- if (GV->hasWeakLinkage())
+ if (GV->isWeakForLinker() && !GV->hasCommonLinkage())
return ELFSym::STB_WEAK;
return ELFSym::STB_GLOBAL;
return ELFSym::STT_OBJECT;
}
-// getElfSectionFlags - Get the ELF Section Header flags 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;
-}
-
-// isELFUndefSym - the symbol has no section and must be placed in
-// the symbol table with a reference to the null section.
-static bool isELFUndefSym(const GlobalValue *GV) {
- return GV->isDeclaration();
-}
-
-// isELFBssSym - for an undef or null value, the symbol must go to a bss
-// section if it's not weak for linker, otherwise it's a common sym.
-static bool isELFBssSym(const GlobalValue *GV) {
- return (!GV->isDeclaration() &&
- (GV->isNullValue() || isa<UndefValue>(GV)) &&
- !GV->isWeakForLinker());
+// 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));
}
-// isELFCommonSym - for an undef or null value, the symbol must go to a
-// common section if it's weak for linker, otherwise bss.
-static bool isELFCommonSym(const GlobalValue *GV) {
- return (!GV->isDeclaration() &&
- (GV->isNullValue() || isa<UndefValue>(GV))
- && GV->isWeakForLinker());
-}
+// 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");
-// isELFDataSym - if the symbol is an initialized but no null constant
-// it must go to some kind of data section gathered from TAI
-static bool isELFDataSym(const GlobalValue *GV) {
- return (!GV->isDeclaration() &&
- !(GV->isNullValue() || isa<UndefValue>(GV)));
+ 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 {
+ // 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;
+ }
}
// EmitGlobal - Choose the right section for global and emit it
void ELFWriter::EmitGlobal(const GlobalValue *GV) {
+ // 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);
- ELFSym *GblSym = new ELFSym(GV);
- GblSym->setBind(SymBind);
- GblSym->setVisibility(getGlobalELFVisibility(GV));
- GblSym->setType(getGlobalELFType(GV));
+ unsigned SymType = getGlobalELFType(GV);
+ bool IsUndefSym = IsELFUndefSym(GV);
- if (isELFUndefSym(GV)) {
- GblSym->SectionIdx = ELFSection::SHN_UNDEF;
- } else {
+ 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);
- // Get ELF section from TAI
- const Section *S = TAI->SectionForGlobal(GV);
- unsigned SectionFlags = getElfSectionFlags(S->getFlags());
+ // 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 Size = TD->getTypeAllocSize(GVar->getInitializer()->getType());
GblSym->Size = Size;
- if (isELFCommonSym(GV)) {
+ if (S->IsCommon()) { // Symbol must go to a common section
GblSym->SectionIdx = ELFSection::SHN_COMMON;
- getSection(S->getName(), ELFSection::SHT_NOBITS, SectionFlags, 1);
// 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 (isELFBssSym(GV)) {
- ELFSection &ES =
- getSection(S->getName(), ELFSection::SHT_NOBITS, SectionFlags);
+ } else if (Kind.isBSS() || Kind.isThreadBSS()) { // Symbol goes to BSS.
GblSym->SectionIdx = ES.SectionIdx;
// Update the size with alignment and the next object can
GblSym->Value = ES.Size;
ES.Size += Size;
- } else if (isELFDataSym(GV)) {
- ELFSection &ES =
- getSection(S->getName(), ELFSection::SHT_PROGBITS, SectionFlags);
+ } 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);
- GblSym->Value = (ES.size() + (Align-1)) & (-Align);
- ES.emitAlignment(ES.Align);
+ ES.emitAlignment(Align);
+ GblSym->Value = ES.size();
// Emit the global to the data section 'ES'
EmitGlobalConstant(GVar->getInitializer(), ES);
}
}
- // Private symbols must never go to the symbol table.
- unsigned SymIdx = 0;
- if (GV->hasPrivateLinkage()) {
- PrivateSyms.push_back(GblSym);
- SymIdx = PrivateSyms.size()-1;
- } else {
- SymbolList.push_back(GblSym);
- }
-
- GblSymLookup[GV] = SymIdx;
+ AddToSymbolList(GblSym);
}
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!");
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) {
- llvm_unreachable("X86_FP80Ty global emission not implemented");
- } else if (CFP->getType() == Type::PPC_FP128Ty)
+ APInt Val = CFP->getValueAPF().bitcastToAPInt();
+ if (CFP->getType() == Type::getDoubleTy(CV->getContext()))
+ GblS.emitWord64(Val.getZExtValue());
+ else if (CFP->getType() == Type::getFloatTy(CV->getContext()))
+ GblS.emitWord32(Val.getZExtValue());
+ else if (CFP->getType() == Type::getX86_FP80Ty(CV->getContext())) {
+ unsigned PadSize =
+ TD->getTypeAllocSize(Type::getX86_FP80Ty(CV->getContext()))-
+ TD->getTypeStoreSize(Type::getX86_FP80Ty(CV->getContext()));
+ GblS.emitWordFP80(Val.getRawData(), PadSize);
+ } else if (CFP->getType() == Type::getPPC_FP128Ty(CV->getContext()))
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
- llvm_unreachable("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");
}
- llvm_unreachable("unknown global constant");
+ 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);
+ }
+}
+
+/// 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 ElfCE object above.
// Build and emit data, bss and "common" sections.
for (Module::global_iterator I = M.global_begin(), E = M.global_end();
- I != E; ++I) {
+ 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) {
- // No need to emit the symbol again
- if (GblSymLookup.find(*I) != GblSymLookup.end())
- continue;
+ for (PendingGblsIter I = PendingGlobals.begin(), E = PendingGlobals.end();
+ I != E; ++I)
EmitGlobal(*I);
- }
+
+ // 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())
// 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 = new ELFSym(0);
+ ELFSym *SectionSym = ELFSym::getSectionSym();
SectionSym->SectionIdx = ES.SectionIdx;
- SectionSym->Size = 0;
- SectionSym->setBind(ELFSym::STB_LOCAL);
- SectionSym->setType(ELFSym::STT_SECTION);
- SectionSym->setVisibility(ELFSym::STV_DEFAULT);
SymbolList.push_back(SectionSym);
ES.Sym = SymbolList.back();
}
// Emit string table
- EmitStringTable();
+ EmitStringTable(M.getModuleIdentifier());
// Emit the symbol table now, if non-empty.
EmitSymbolTable();
// 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];
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;
+ Addend = PrivateSyms[SymIdx]->Value + GlobalOffset;
SymIdx = SectionList[SectionIdx]->getSymbolTableIndex();
} else {
- Addend = TEW->getDefaultAddendForRelTy(RelType);
+ 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();
SymIdx = SectionList[SectionIdx]->getSymbolTableIndex();
- Addend = (uint64_t)MR.getResultPointer();
+
+ // 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(Addend, RelOffset, RelType);
+ int64_t Value = TEW->computeRelocation(SymOffset, RelOffset, RelType);
RelocateField(S, RelOffset, Value, RelTySize);
continue;
}
- // Handle Jump Table Index relocation
- if ((SectionIdx == getJumpTableSection().SectionIdx) &&
- TEW->hasCustomJumpTableIndexRelTy()) {
- RelType = TEW->getJumpTableIndexRelTy();
- RelTySize = TEW->getRelocationTySize(RelType);
- }
+ 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
- if (!HasRelA)
- RelocateField(S, RelOffset, Addend, RelTySize);
+ // 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(RelOffset, SymIdx, RelType, HasRelA, Addend);
/// 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();
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 (Sym.GV) Name.append(Mang->getMangledName(Sym.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()) {
Sym.NameIdx = 0;
// Size of each symtab entry.
SymTab.EntSize = TEW->getSymTabEntrySize();
- // The first entry in the symtab is the null symbol
- SymbolList.insert(SymbolList.begin(), new ELFSym(0));
-
// Reorder the symbol table with local symbols first!
unsigned FirstNonLocalSymbol = SortSymbols();
// Emit symbol to the symbol table
EmitSymbol(SymTab, Sym);
- // Record the symbol table index for each global value
- if (Sym.GV) GblSymLookup[Sym.GV] = i;
+ // 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
Sym.SymTabIdx = i;
projects / oota-llvm.git / blobdiff