#include "llvm/Support/Streams.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Support/Debug.h"
+#include "llvm/Support/ErrorHandling.h"
using namespace llvm;
return false;
}
+// 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:
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;
return ELFSym::STB_GLOBAL;
}
-// getElfSectionFlags - Get the ELF Section Header based on the
-// flags defined in ELFTargetAsmInfo.
+// getGlobalELFType - Returns the ELF specific type for a global
+unsigned ELFWriter::getGlobalELFType(const GlobalValue *GV) {
+ if (GV->isDeclaration())
+ return ELFSym::STT_NOTYPE;
+
+ if (isa<Function>(GV))
+ return ELFSym::STT_FUNC;
+
+ 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;
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();
- }
-
- // 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";
+// 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();
+}
- 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;
- }
+// 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());
+}
- Sym.IsConstant = true;
- ELFSection &ElfS = getSection(S->getName(), SectionType, SectionFlags);
- Sym.SectionIdx = ElfS.SectionIdx;
- ElfS.Align = std::max(ElfS.Align, Align);
- return ElfS;
+// 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());
}
-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);
+// 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)));
}
-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));
+// EmitGlobal - Choose the right section for global and emit it
+void ELFWriter::EmitGlobal(const GlobalValue *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;
+ // 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));
+
+ if (isELFUndefSym(GV)) {
+ GblSym->SectionIdx = ELFSection::SHN_UNDEF;
} else {
- GblSym.setType(ELFSym::STT_NOTYPE);
- }
+ assert(isa<GlobalVariable>(GV) && "GV not a global variable!");
+ const GlobalVariable *GVar = dyn_cast<GlobalVariable>(GV);
- 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);
- }
+ // Get ELF section from TAI
+ const Section *S = TAI->SectionForGlobal(GV);
+ unsigned SectionFlags = getElfSectionFlags(S->getFlags());
- // 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);
+ // 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 (isELFCommonSym(GV)) {
+ 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;
+
+ } else if (isELFBssSym(GV)) {
+ ELFSection &ES =
+ getSection(S->getName(), ELFSection::SHT_NOBITS, SectionFlags);
+ 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 if (isELFDataSym(GV)) {
+ ELFSection &ES =
+ getSection(S->getName(), ELFSection::SHT_PROGBITS, SectionFlags);
+ 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);
+
+ // Emit the global to the data section 'ES'
+ EmitGlobalConstant(GVar->getInitializer(), ES);
+ }
}
+
+ if (!GV->hasPrivateLinkage())
+ SymbolList.push_back(GblSym);
}
void ELFWriter::EmitGlobalConstantStruct(const ConstantStruct *CVS,
else if (CFP->getType() == Type::FloatTy)
GblS.emitWord32(Val);
else if (CFP->getType() == Type::X86_FP80Ty) {
- assert(0 && "X86_FP80Ty global emission not implemented");
+ llvm_unreachable("X86_FP80Ty global emission not implemented");
} else if (CFP->getType() == Type::PPC_FP128Ty)
- assert(0 && "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
- assert(0 && "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();
EmitGlobalConstant(CP->getOperand(I), GblS);
return;
}
- assert(0 && "unknown global constant");
+ llvm_unreachable("unknown global constant");
}
// 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);
+ EmitGlobal(I);
GblSymLookup[I] = 0;
}
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");
- }
+ EmitGlobal(*I);
GblSymLookup[*I] = 0;
}
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;
void ELFWriter::EmitRelocations() {
// 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;
+ if (!S.hasRelocations()) continue;
- // Get the relocation section for section 'I'
+ // Get the relocation section for section 'S'
bool HasRelA = TEW->hasRelocationAddend();
- ELFSection &RelSec = getRelocSection(I->getName(), HasRelA,
+ ELFSection &RelSec = getRelocSection(S.getName(), HasRelA,
TEW->getPrefELFAlignment());
// '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;
// Target specific ELF relocation type
unsigned RelType = TEW->getRelocationType(MR.getRelocationType());
- // Constant addend used to compute the value to be stored
+ // Constant addend used to compute the value to be stored
// into the relocatable field
int64_t Addend = 0;
SymIdx = GblSymLookup[G];
Addend = TEW->getAddendForRelTy(RelType);
} else {
+ // Get the symbol index for the section symbol referenced
+ // by the relocation
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]->Sym->SymTabIdx;
Addend = (uint64_t)MR.getResultPointer();
}
/// 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);
// 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) GblSymLookup[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