return false;
}
+// Get jump table section on the section name returned by TAI
+ELFSection &ELFWriter::getJumpTableSection() {
+ unsigned Align = TM.getTargetData()->getPointerABIAlignment();
+ return getSection(TAI->getJumpTableDataSection(),
+ ELFSection::SHT_PROGBITS,
+ ELFSection::SHF_ALLOC, Align);
+}
+
+// Get a constant pool section based on the section name returned by TAI
+ELFSection &ELFWriter::getConstantPoolSection(MachineConstantPoolEntry &CPE) {
+ uint64_t Size = TM.getTargetData()->getTypeAllocSize(CPE.getType());
+
+ std::string CstPoolName =
+ TAI->getSectionForMergableConstant(Size,CPE.getRelocationInfo())->getName();
+ return getSection(CstPoolName,
+ ELFSection::SHT_PROGBITS,
+ ELFSection::SHF_MERGE | ELFSection::SHF_ALLOC,
+ CPE.getAlignment());
+}
+
+// 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");
+ if (TEW->hasRelocationAddend())
+ RelSName.append("a");
+ RelSName.append(S.getName());
+
+ return getSection(RelSName, SectionHeaderTy, 0, TEW->getPrefELFAlignment());
+}
+
// getGlobalELFVisibility - Returns the ELF specific visibility type
unsigned ELFWriter::getGlobalELFVisibility(const GlobalValue *GV) {
switch (GV->getVisibility()) {
default:
- LLVM_UNREACHABLE("unknown visibility type");
+ llvm_unreachable("unknown visibility type");
case GlobalValue::DefaultVisibility:
return ELFSym::STV_DEFAULT;
case GlobalValue::HiddenVisibility:
// 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());
+static bool isELFBssSym(const GlobalVariable *GV) {
+ const Constant *CV = GV->getInitializer();
+ return ((CV->isNullValue() || isa<UndefValue>(CV)) && !GV->isWeakForLinker());
}
// 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());
+static bool isELFCommonSym(const GlobalVariable *GV) {
+ const Constant *CV = GV->getInitializer();
+ return ((CV->isNullValue() || isa<UndefValue>(CV)) && GV->isWeakForLinker());
}
// 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)));
+static bool isELFDataSym(const Constant *CV) {
+ return (!(CV->isNullValue() || isa<UndefValue>(CV)));
}
// 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(GV);
- GblSym.setBind(SymBind);
- GblSym.setVisibility(getGlobalELFVisibility(GV));
- GblSym.setType(getGlobalELFType(GV));
+ ELFSym *GblSym = new ELFSym(GV);
+ GblSym->setBind(SymBind);
+ GblSym->setVisibility(getGlobalELFVisibility(GV));
+ GblSym->setType(getGlobalELFType(GV));
if (isELFUndefSym(GV)) {
- GblSym.SectionIdx = ELFSection::SHN_UNDEF;
+ GblSym->SectionIdx = ELFSection::SHN_UNDEF;
} else {
assert(isa<GlobalVariable>(GV) && "GV not a global variable!");
const GlobalVariable *GVar = dyn_cast<GlobalVariable>(GV);
const TargetData *TD = TM.getTargetData();
unsigned Align = TD->getPreferredAlignment(GVar);
unsigned Size = TD->getTypeAllocSize(GVar->getInitializer()->getType());
- GblSym.Size = Size;
+ GblSym->Size = Size;
- if (isELFCommonSym(GV)) {
- GblSym.SectionIdx = ELFSection::SHN_COMMON;
+ if (isELFCommonSym(GVar)) {
+ 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.
- GblSym.Value = Align;
+ GblSym->Value = Align;
- } else if (isELFBssSym(GV)) {
+ } else if (isELFBssSym(GVar)) {
ELFSection &ES =
getSection(S->getName(), ELFSection::SHT_NOBITS, SectionFlags);
- GblSym.SectionIdx = ES.SectionIdx;
+ 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.
+ // 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;
+ GblSym->Value = ES.Size;
ES.Size += Size;
} else if (isELFDataSym(GV)) {
ELFSection &ES =
getSection(S->getName(), ELFSection::SHT_PROGBITS, SectionFlags);
- GblSym.SectionIdx = ES.SectionIdx;
+ GblSym->SectionIdx = ES.SectionIdx;
- // GblSym.Value should contain the symbol offset inside the section,
+ // 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);
+ GblSym->Value = (ES.size() + (Align-1)) & (-Align);
ES.emitAlignment(ES.Align);
// Emit the global to the data section 'ES'
}
}
- // 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);
+ // 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);
}
+
+ setGlobalSymLookup(GV, SymIdx);
}
void ELFWriter::EmitGlobalConstantStruct(const ConstantStruct *CVS,
else if (CFP->getType() == Type::FloatTy)
GblS.emitWord32(Val);
else if (CFP->getType() == Type::X86_FP80Ty) {
- LLVM_UNREACHABLE("X86_FP80Ty global emission not implemented");
+ llvm_unreachable("X86_FP80Ty global emission not implemented");
} else if (CFP->getType() == Type::PPC_FP128Ty)
- LLVM_UNREACHABLE("PPC_FP128Ty global emission not implemented");
+ llvm_unreachable("PPC_FP128Ty global emission not implemented");
return;
} else if (const ConstantInt *CI = dyn_cast<ConstantInt>(CV)) {
if (Size == 4)
else if (Size == 8)
GblS.emitWord64(CI->getZExtValue());
else
- LLVM_UNREACHABLE("LargeInt global emission not implemented");
+ llvm_unreachable("LargeInt global emission not implemented");
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 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.
+
+ // Check if the referenced symbol is already emitted
+ if (GblSymLookup.find(GV) == GblSymLookup.end())
+ EmitGlobal(GV);
+
+ // Create the relocation entry for the global value
+ MachineRelocation MR =
+ MachineRelocation::getGV(GblS.getCurrentPCOffset(),
+ TEW->getAbsoluteLabelMachineRelTy(),
+ const_cast<GlobalValue*>(GV));
+
+ // Fill the data entry with zeros
+ for (unsigned i=0; i < Size; ++i)
+ GblS.emitByte(0);
+
+ // Add the relocation entry for the current data section
+ GblS.addRelocation(MR);
+ return;
+ } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(CV)) {
+ if (CE->getOpcode() == Instruction::BitCast) {
+ EmitGlobalConstant(CE->getOperand(0), GblS);
+ return;
+ }
+ // See AsmPrinter::EmitConstantValueOnly for other ConstantExpr types
+ llvm_unreachable("Unsupported ConstantExpr type");
}
- LLVM_UNREACHABLE("unknown global constant");
+
+ llvm_unreachable("Unknown global constant type");
}
// 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);
- GblSymLookup[I] = 0;
- }
// 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;
-
+ E = PendingGlobals.end(); I != E; ++I)
EmitGlobal(*I);
- GblSymLookup[*I] = 0;
- }
// Emit non-executable stack note
if (TAI->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 = new ELFSym(0);
+ 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
OutputSectionsAndSectionTable();
// We are done with the abstract symbols.
+ SymbolList.clear();
SectionList.clear();
NumSections = 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
if (MR.isGlobalValue()) {
const GlobalValue *G = MR.getGlobalValue();
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;
+ SymIdx = SectionList[SectionIdx]->getSymbolTableIndex();
+ } else {
+ 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;
- }
+ SymIdx = SectionList[SectionIdx]->getSymbolTableIndex();
Addend = (uint64_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);
+ RelocateField(S, RelOffset, Value, RelTySize);
+ continue;
+ }
+
+ // Handle Jump Table Index relocation
+ if ((SectionIdx == getJumpTableSection().SectionIdx) &&
+ TEW->hasCustomJumpTableIndexRelTy()) {
+ RelType = TEW->getJumpTableIndexRelTy();
+ RelTySize = TEW->getRelocationTySize(RelType);
+ }
}
+ // 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);
+
// 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);
}
}
// 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.GV) Name.append(Mang->getMangledName(Sym.GV));
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.
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();
SymTab.EntSize = TEW->getSymTabEntrySize();
// The first entry in the symtab is the null symbol
- ELFSym NullSym = ELFSym(0);
- EmitSymbol(SymTab, NullSym);
+ SymbolList.insert(SymbolList.begin(), new ELFSym(0));
- // 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++;
+ // Reorder the symbol table with local symbols first!
+ unsigned FirstNonLocalSymbol = SortSymbols();
+
+ // 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;
+ if (Sym.GV) setGlobalSymLookup(Sym.GV, 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();
}
// 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.
// 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.
BinaryObject SHdrTable(isLittleEndian, is64Bit);
// Emit all of sections to the file and build the section header table.
- while (!SectionList.empty()) {
- ELFSection &S = *SectionList.begin();
+ for (ELFSectionIter I=SectionList.begin(), E=SectionList.end(); I != E; ++I) {
+ ELFSection &S = *(*I);
DOUT << "SectionIdx: " << S.SectionIdx << ", Name: " << S.getName()
<< ", Size: " << S.Size << ", Offset: " << S.Offset
<< ", SectionData Size: " << S.size() << "\n";
}
EmitSectionHeader(SHdrTable, S);
- SectionList.pop_front();
}
// Align output for the section table.
projects / oota-llvm.git / blobdiff