//
// The LLVM Compiler Infrastructure
//
-// This file was developed by the LLVM research group and is distributed under
-// the University of Illinois Open Source License. See LICENSE.TXT for details.
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// #3. ".bss" entry - global variables without initializers. [ if needed ]
// ...
// #N. ".shstrtab" entry - String table for the section names.
-
-//
-// NOTE: This code should eventually be extended to support 64-bit ELF (this
-// won't be hard), but we haven't done so yet!
//
//===----------------------------------------------------------------------===//
-#include "llvm/CodeGen/ELFWriter.h"
+#define DEBUG_TYPE "elfwriter"
+
+#include "ELF.h"
+#include "ELFWriter.h"
+#include "ELFCodeEmitter.h"
+#include "llvm/Constants.h"
#include "llvm/Module.h"
+#include "llvm/PassManager.h"
+#include "llvm/DerivedTypes.h"
+#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/Target/TargetData.h"
+#include "llvm/Target/TargetELFWriterInfo.h"
#include "llvm/Target/TargetMachine.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;
-ELFWriter::ELFWriter(std::ostream &o, TargetMachine &tm) : O(o), TM(tm) {
- e_machine = 0; // e_machine defaults to 'No Machine'
- e_flags = 0; // e_flags defaults to 0, no flags.
+char ELFWriter::ID = 0;
+/// AddELFWriter - Concrete function to 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 (ObjectCodeEmitter*) &EW->getMachineCodeEmitter();
+}
+
+//===----------------------------------------------------------------------===//
+// ELFWriter Implementation
+//===----------------------------------------------------------------------===//
- is64Bit = TM.getTargetData().getPointerSizeInBits() == 64;
- isLittleEndian = TM.getTargetData().isLittleEndian();
+ELFWriter::ELFWriter(raw_ostream &o, TargetMachine &tm)
+ : MachineFunctionPass(&ID), O(o), TM(tm),
+ is64Bit(TM.getTargetData()->getPointerSizeInBits() == 64),
+ isLittleEndian(TM.getTargetData()->isLittleEndian()),
+ ElfHdr(isLittleEndian, is64Bit) {
+
+ TAI = TM.getTargetAsmInfo();
+ TEW = TM.getELFWriterInfo();
+
+ // Create the machine code emitter object for this target.
+ MCE = new ELFCodeEmitter(*this);
+
+ // Inital number of sections
+ NumSections = 0;
+}
+
+ELFWriter::~ELFWriter() {
+ delete MCE;
}
// doInitialization - Emit the file header and all of the global variables for
// the module to the ELF file.
bool ELFWriter::doInitialization(Module &M) {
- outbyte(0x7F); // EI_MAG0
- outbyte('E'); // EI_MAG1
- outbyte('L'); // EI_MAG2
- outbyte('F'); // EI_MAG3
- outbyte(is64Bit ? 2 : 1); // EI_CLASS
- outbyte(isLittleEndian ? 1 : 2); // EI_DATA
- outbyte(1); // EI_VERSION
- for (unsigned i = OutputBuffer.size(); i != 16; ++i)
- outbyte(0); // EI_PAD up to 16 bytes.
-
- // This should change for shared objects.
- outhalf(1); // e_type = ET_REL
- outhalf(e_machine); // e_machine = whatever the target wants
- outword(1); // e_version = 1
- outaddr(0); // e_entry = 0 -> no entry point in .o file
- outaddr(0); // e_phoff = 0 -> no program header for .o
-
- ELFHeader_e_shoff_Offset = OutputBuffer.size();
- outaddr(0); // e_shoff
- outword(e_flags); // e_flags = whatever the target wants
-
- assert(!is64Bit && "These sizes need to be adjusted for 64-bit!");
- outhalf(52); // e_ehsize = ELF header size
- outhalf(0); // e_phentsize = prog header entry size
- outhalf(0); // e_phnum = # prog header entries = 0
- outhalf(40); // e_shentsize = sect header entry size
-
-
- ELFHeader_e_shnum_Offset = OutputBuffer.size();
- outhalf(0); // e_shnum = # of section header ents
- ELFHeader_e_shstrndx_Offset = OutputBuffer.size();
- outhalf(0); // e_shstrndx = Section # of '.shstrtab'
-
- // Add the null section.
- SectionList.push_back(ELFSection());
-
- // Start up the symbol table. The first entry in the symtab is the null
- // entry.
- SymbolTable.push_back(ELFSym(0));
-
-
-
- // FIXME: Should start the .text section.
+ Mang = new Mangler(M);
+
+ // ELF Header
+ // ----------
+ // Fields e_shnum e_shstrndx are only known after all section have
+ // been emitted. They locations in the ouput buffer are recorded so
+ // to be patched up later.
+ //
+ // Note
+ // ----
+ // emitWord method behaves differently for ELF32 and ELF64, writing
+ // 4 bytes in the former and 8 in the last for *_off and *_addr elf types
+
+ ElfHdr.emitByte(0x7f); // e_ident[EI_MAG0]
+ ElfHdr.emitByte('E'); // e_ident[EI_MAG1]
+ ElfHdr.emitByte('L'); // e_ident[EI_MAG2]
+ ElfHdr.emitByte('F'); // e_ident[EI_MAG3]
+
+ ElfHdr.emitByte(TEW->getEIClass()); // e_ident[EI_CLASS]
+ ElfHdr.emitByte(TEW->getEIData()); // e_ident[EI_DATA]
+ ElfHdr.emitByte(EV_CURRENT); // e_ident[EI_VERSION]
+ ElfHdr.emitAlignment(16); // e_ident[EI_NIDENT-EI_PAD]
+
+ ElfHdr.emitWord16(ET_REL); // e_type
+ ElfHdr.emitWord16(TEW->getEMachine()); // e_machine = target
+ ElfHdr.emitWord32(EV_CURRENT); // e_version
+ ElfHdr.emitWord(0); // e_entry, no entry point in .o file
+ ElfHdr.emitWord(0); // e_phoff, no program header for .o
+ ELFHdr_e_shoff_Offset = ElfHdr.size();
+ ElfHdr.emitWord(0); // e_shoff = sec hdr table off in bytes
+ ElfHdr.emitWord32(TEW->getEFlags()); // e_flags = whatever the target wants
+ ElfHdr.emitWord16(TEW->getHdrSize()); // e_ehsize = ELF header size
+ ElfHdr.emitWord16(0); // e_phentsize = prog header entry size
+ ElfHdr.emitWord16(0); // e_phnum = # prog header entries = 0
+
+ // e_shentsize = Section header entry size
+ ElfHdr.emitWord16(TEW->getSHdrSize());
+
+ // e_shnum = # of section header ents
+ ELFHdr_e_shnum_Offset = ElfHdr.size();
+ ElfHdr.emitWord16(0); // Placeholder
+
+ // e_shstrndx = Section # of '.shstrtab'
+ ELFHdr_e_shstrndx_Offset = ElfHdr.size();
+ ElfHdr.emitWord16(0); // Placeholder
+
+ // Add the null section, which is required to be first in the file.
+ getNullSection();
+
return false;
}
-void ELFWriter::EmitGlobal(GlobalVariable *GV, ELFSection &DataSection,
- ELFSection &BSSSection) {
- // If this is an external global, emit it...
- assert(GV->hasInitializer() && "FIXME: unimp");
-
- // If this global has a zero initializer, it is part of the .bss or common
- // section.
- if (GV->getInitializer()->isNullValue()) {
- // If this global is part of the common block, add it now. Variables are
- // part of the common block if they are zero initialized and allowed to be
- // merged with other symbols.
- if (GV->hasLinkOnceLinkage() || GV->hasWeakLinkage()) {
- ELFSym CommonSym(GV);
- // Value for common symbols is the alignment required.
- const Type *GVType = (const Type*)GV->getType();
- CommonSym.Value = TM.getTargetData().getTypeAlignment(GVType);
- CommonSym.Size = TM.getTargetData().getTypeSize(GVType);
- CommonSym.SetBind(ELFSym::STB_GLOBAL);
- CommonSym.SetType(ELFSym::STT_OBJECT);
- // TODO SOMEDAY: add ELF visibility.
- CommonSym.SectionIdx = ELFSection::SHN_COMMON;
- SymbolTable.push_back(CommonSym);
- return;
+unsigned ELFWriter::getGlobalELFVisibility(const GlobalValue *GV) {
+ switch (GV->getVisibility()) {
+ default:
+ assert(0 && "unknown visibility type");
+ case GlobalValue::DefaultVisibility:
+ return ELFSym::STV_DEFAULT;
+ case GlobalValue::HiddenVisibility:
+ return ELFSym::STV_HIDDEN;
+ case GlobalValue::ProtectedVisibility:
+ return ELFSym::STV_PROTECTED;
+ }
+
+ return 0;
+}
+
+unsigned ELFWriter::getGlobalELFLinkage(const GlobalValue *GV) {
+ if (GV->hasInternalLinkage())
+ return ELFSym::STB_LOCAL;
+
+ if (GV->hasWeakLinkage())
+ 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();
+ }
+
+ // 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";
+
+ 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;
+ }
- // FIXME: Implement the .bss section.
- return;
+ Sym.IsConstant = true;
+ ELFSection &ElfS = getSection(S->getName(), SectionType, SectionFlags);
+ Sym.SectionIdx = ElfS.SectionIdx;
+ ElfS.Align = std::max(ElfS.Align, Align);
+ return ElfS;
+}
+
+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);
+}
+
+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;
+ } else {
+ GblSym.setType(ELFSym::STT_NOTYPE);
}
- // FIXME: handle .rodata
- //assert(!GV->isConstant() && "unimp");
+ 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);
+ }
+
+ // 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);
+ }
+}
+
+void ELFWriter::EmitGlobalConstantStruct(const ConstantStruct *CVS,
+ ELFSection &GblS) {
+
+ // Print the fields in successive locations. Pad to align if needed!
+ const TargetData *TD = TM.getTargetData();
+ unsigned Size = TD->getTypeAllocSize(CVS->getType());
+ const StructLayout *cvsLayout = TD->getStructLayout(CVS->getType());
+ uint64_t sizeSoFar = 0;
+ for (unsigned i = 0, e = CVS->getNumOperands(); i != e; ++i) {
+ const Constant* field = CVS->getOperand(i);
+
+ // Check if padding is needed and insert one or more 0s.
+ uint64_t fieldSize = TD->getTypeAllocSize(field->getType());
+ uint64_t padSize = ((i == e-1 ? Size : cvsLayout->getElementOffset(i+1))
+ - cvsLayout->getElementOffset(i)) - fieldSize;
+ sizeSoFar += fieldSize + padSize;
+
+ // Now print the actual field value.
+ EmitGlobalConstant(field, GblS);
+
+ // 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);
+ }
+ assert(sizeSoFar == cvsLayout->getSizeInBytes() &&
+ "Layout of constant struct may be incorrect!");
+}
- // FIXME: handle .data
- //assert(0 && "unimp");
+void ELFWriter::EmitGlobalConstant(const Constant *CV, ELFSection &GblS) {
+ const TargetData *TD = TM.getTargetData();
+ 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);
+ }
+ 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");
+ return;
+ } else if (const ConstantInt *CI = dyn_cast<ConstantInt>(CV)) {
+ if (Size == 4)
+ GblS.emitWord32(CI->getZExtValue());
+ else if (Size == 8)
+ GblS.emitWord64(CI->getZExtValue());
+ else
+ assert(0 && "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;
+ }
+ assert(0 && "unknown global constant");
}
bool ELFWriter::runOnMachineFunction(MachineFunction &MF) {
+ // Nothing to do here, this is all done through the MCE object above.
return false;
}
/// doFinalization - Now that the module has been completely processed, emit
/// the ELF file to 'O'.
bool ELFWriter::doFinalization(Module &M) {
- // Okay, the .text section has now been finalized.
- // FIXME: finalize the .text section.
+ /// 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]);
+ }
- // Okay, the ELF header and .text sections have been completed, build the
- // .data, .bss, and "common" sections next.
- ELFSection DataSection(".data", OutputBuffer.size());
- ELFSection BSSSection (".bss");
+ // Emit .data section placeholder
+ getDataSection();
+
+ // Emit .bss section placeholder
+ getBSSSection();
+
+ // Build and emit data, bss and "common" sections.
for (Module::global_iterator I = M.global_begin(), E = M.global_end();
- I != E; ++I)
- EmitGlobal(I, DataSection, BSSSection);
-
- // If the .data section is nonempty, add it to our list.
- if (DataSection.Size) {
- DataSection.Align = 4; // FIXME: Compute!
- // FIXME: Set the right flags and stuff.
- SectionList.push_back(DataSection);
+ I != E; ++I) {
+ EmitGlobalVar(I);
+ GblSymLookup[I] = 0;
}
- // If the .bss section is nonempty, add it to our list.
- if (BSSSection.Size) {
- BSSSection.Offset = OutputBuffer.size();
- BSSSection.Align = 4; // FIXME: Compute!
- // FIXME: Set the right flags and stuff.
- SectionList.push_back(BSSSection);
+ // 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;
+
+ 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 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 string table
+ EmitStringTable();
+
// Emit the symbol table now, if non-empty.
EmitSymbolTable();
- // FIXME: Emit the relocations now.
+ // Emit the relocation sections.
+ EmitRelocations();
- // Emit the string table for the sections in the ELF file we have.
+ // Emit the sections string table.
EmitSectionTableStringTable();
- // Emit the .o file section table.
- EmitSectionTable();
+ // Dump the sections and section table to the .o file.
+ OutputSectionsAndSectionTable();
- // Emit the .o file to the specified stream.
- O.write((char*)&OutputBuffer[0], OutputBuffer.size());
+ // We are done with the abstract symbols.
+ SectionList.clear();
+ NumSections = 0;
- // Free the output buffer.
- std::vector<unsigned char>().swap(OutputBuffer);
+ // Release the name mangler object.
+ delete Mang; Mang = 0;
return false;
}
-/// EmitSymbolTable - If the current symbol table is non-empty, emit the string
-/// table for it and then the symbol table itself.
-void ELFWriter::EmitSymbolTable() {
- if (SymbolTable.size() == 1) return; // Only the null entry.
+/// EmitRelocations - Emit relocations
+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) {
+
+ // 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());
+
+ // '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.EntSize = TEW->getRelocationEntrySize();
+
+ // Get the relocations from Section
+ std::vector<MachineRelocation> Relos = I->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();
+
+ // Symbol index in the symbol table
+ unsigned SymIdx = 0;
+
+ // Target specific ELF relocation type
+ unsigned RelType = TEW->getRelocationType(MR.getRelocationType());
+
+ // Constant addend used to compute the value to be stored
+ // into the relocatable field
+ 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();
+ SymIdx = GblSymLookup[G];
+ Addend = TEW->getAddendForRelTy(RelType);
+ } else {
+ 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();
+ }
+
+ // Get the relocation entry and emit to the relocation section
+ ELFRelocation Rel(Offset, SymIdx, RelType, HasRelA, Addend);
+ EmitRelocation(RelSec, Rel, HasRelA);
+ }
+ }
+}
- // FIXME: compact all local symbols to the start of the symtab.
- unsigned FirstNonLocalSymbol = 1;
+/// EmitRelocation - Write relocation 'Rel' to the relocation section 'Rel'
+void ELFWriter::EmitRelocation(BinaryObject &RelSec, ELFRelocation &Rel,
+ bool HasRelA) {
+ RelSec.emitWord(Rel.getOffset());
+ RelSec.emitWord(Rel.getInfo(is64Bit));
+ if (HasRelA)
+ RelSec.emitWord(Rel.getAddend());
+}
+
+/// EmitSymbol - Write symbol 'Sym' to the symbol table 'SymbolTable'
+void ELFWriter::EmitSymbol(BinaryObject &SymbolTable, ELFSym &Sym) {
+ if (is64Bit) {
+ SymbolTable.emitWord32(Sym.NameIdx);
+ SymbolTable.emitByte(Sym.Info);
+ SymbolTable.emitByte(Sym.Other);
+ SymbolTable.emitWord16(Sym.SectionIdx);
+ SymbolTable.emitWord64(Sym.Value);
+ SymbolTable.emitWord64(Sym.Size);
+ } else {
+ SymbolTable.emitWord32(Sym.NameIdx);
+ SymbolTable.emitWord32(Sym.Value);
+ SymbolTable.emitWord32(Sym.Size);
+ SymbolTable.emitByte(Sym.Info);
+ SymbolTable.emitByte(Sym.Other);
+ SymbolTable.emitWord16(Sym.SectionIdx);
+ }
+}
+
+/// EmitSectionHeader - Write section 'Section' header in 'SHdrTab'
+/// Section Header Table
+void ELFWriter::EmitSectionHeader(BinaryObject &SHdrTab,
+ const ELFSection &SHdr) {
+ SHdrTab.emitWord32(SHdr.NameIdx);
+ SHdrTab.emitWord32(SHdr.Type);
+ if (is64Bit) {
+ SHdrTab.emitWord64(SHdr.Flags);
+ SHdrTab.emitWord(SHdr.Addr);
+ SHdrTab.emitWord(SHdr.Offset);
+ SHdrTab.emitWord64(SHdr.Size);
+ SHdrTab.emitWord32(SHdr.Link);
+ SHdrTab.emitWord32(SHdr.Info);
+ SHdrTab.emitWord64(SHdr.Align);
+ SHdrTab.emitWord64(SHdr.EntSize);
+ } else {
+ SHdrTab.emitWord32(SHdr.Flags);
+ SHdrTab.emitWord(SHdr.Addr);
+ SHdrTab.emitWord(SHdr.Offset);
+ SHdrTab.emitWord32(SHdr.Size);
+ SHdrTab.emitWord32(SHdr.Link);
+ SHdrTab.emitWord32(SHdr.Info);
+ SHdrTab.emitWord32(SHdr.Align);
+ SHdrTab.emitWord32(SHdr.EntSize);
+ }
+}
- SectionList.push_back(ELFSection(".strtab", OutputBuffer.size()));
- ELFSection &StrTab = SectionList.back();
- StrTab.Type = ELFSection::SHT_STRTAB;
- StrTab.Align = 1;
+/// EmitStringTable - If the current symbol table is non-empty, emit the string
+/// table for it
+void ELFWriter::EmitStringTable() {
+ if (!SymbolList.size()) return; // Empty symbol table.
+ ELFSection &StrTab = getStringTableSection();
// Set the zero'th symbol to a null byte, as required.
- outbyte(0);
- SymbolTable[0].NameIdx = 0;
+ StrTab.emitByte(0);
+
+ // Walk on the symbol list and write symbol names into the
+ // string table.
unsigned Index = 1;
- for (unsigned i = 1, e = SymbolTable.size(); i != e; ++i) {
- // FIXME: USE A MANGLER!!
- const std::string &Name = SymbolTable[i].GV->getName();
+ for (std::list<ELFSym>::iterator I = SymbolList.begin(),
+ E = SymbolList.end(); I != E; ++I) {
+
+ // Use the name mangler to uniquify the LLVM symbol.
+ std::string Name;
+ if (I->GV) Name.append(Mang->getValueName(I->GV));
if (Name.empty()) {
- SymbolTable[i].NameIdx = 0;
+ I->NameIdx = 0;
} else {
- SymbolTable[i].NameIdx = Index;
-
- // Add the name to the output buffer, including the null terminator.
- OutputBuffer.insert(OutputBuffer.end(), Name.begin(), Name.end());
-
- // Add a null terminator.
- OutputBuffer.push_back(0);
+ I->NameIdx = Index;
+ StrTab.emitString(Name);
// Keep track of the number of bytes emitted to this section.
Index += Name.size()+1;
}
}
+ assert(Index == StrTab.size());
+ StrTab.Size = Index;
+}
- StrTab.Size = OutputBuffer.size()-StrTab.Offset;
+/// 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.
- assert(!is64Bit && "Should this be 8 byte aligned for 64-bit?"
- " (check .Align below also)");
- align(4);
-
- SectionList.push_back(ELFSection(".symtab", OutputBuffer.size()));
- ELFSection &SymTab = SectionList.back();
- SymTab.Type = ELFSection::SHT_SYMTAB;
- SymTab.Align = 4; // FIXME: check for ELF64
- SymTab.Link = SectionList.size()-2; // Section Index of .strtab.
- SymTab.Info = FirstNonLocalSymbol; // First non-STB_LOCAL symbol.
- SymTab.EntSize = 16; // Size of each symtab entry. FIXME: wrong for ELF64
-
- assert(!is64Bit && "check this!");
- for (unsigned i = 0, e = SymbolTable.size(); i != e; ++i) {
- ELFSym &Sym = SymbolTable[i];
- outword(Sym.NameIdx);
- outaddr(Sym.Value);
- outword(Sym.Size);
- outbyte(Sym.Info);
- outbyte(Sym.Other);
- outhalf(Sym.SectionIdx);
+ ELFSection &SymTab = getSymbolTableSection();
+ SymTab.Align = TEW->getPrefELFAlignment();
+
+ // Section Index of .strtab.
+ SymTab.Link = getStringTableSection().SectionIdx;
+
+ // 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);
+
+ // 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 symbol to the symbol table
+ EmitSymbol(SymTab, *I);
+
+ // Record the symbol table index for each global value
+ if (I->GV)
+ GblSymLookup[I->GV] = Index;
+
+ // Keep track on the symbol index into the symbol table
+ I->SymTabIdx = Index;
}
- SymTab.Size = OutputBuffer.size()-SymTab.Offset;
+ SymTab.Info = FirstNonLocalSymbol;
+ SymTab.Size = SymTab.size();
}
/// EmitSectionTableStringTable - This method adds and emits a section for the
/// section names.
void ELFWriter::EmitSectionTableStringTable() {
// First step: add the section for the string table to the list of sections:
- SectionList.push_back(ELFSection(".shstrtab", OutputBuffer.size()));
- SectionList.back().Type = ELFSection::SHT_STRTAB;
+ ELFSection &SHStrTab = getSectionHeaderStringTableSection();
// Now that we know which section number is the .shstrtab section, update the
// e_shstrndx entry in the ELF header.
- fixhalf(SectionList.size()-1, ELFHeader_e_shstrndx_Offset);
+ ElfHdr.fixWord16(SHStrTab.SectionIdx, ELFHdr_e_shstrndx_Offset);
// Set the NameIdx of each section in the string table and emit the bytes for
// the string table.
unsigned Index = 0;
- for (unsigned i = 0, e = SectionList.size(); i != e; ++i) {
+ for (std::list<ELFSection>::iterator I = SectionList.begin(),
+ E = SectionList.end(); I != E; ++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.
- SectionList[i].NameIdx = Index;
-
- // Add the name to the output buffer, including the null terminator.
- OutputBuffer.insert(OutputBuffer.end(), SectionList[i].Name.begin(),
- SectionList[i].Name.end());
- // Add a null terminator.
- OutputBuffer.push_back(0);
+ I->NameIdx = Index;
+ SHStrTab.emitString(I->getName());
// Keep track of the number of bytes emitted to this section.
- Index += SectionList[i].Name.size()+1;
+ Index += I->getName().size()+1;
}
// Set the size of .shstrtab now that we know what it is.
- SectionList.back().Size = Index;
+ assert(Index == SHStrTab.size());
+ SHStrTab.Size = Index;
}
-/// EmitSectionTable - Now that we have emitted the entire contents of the file
-/// (all of the sections), emit the section table which informs the reader where
-/// the boundaries are.
-void ELFWriter::EmitSectionTable() {
- // Now that all of the sections have been emitted, set the e_shnum entry in
- // the ELF header.
- fixhalf(SectionList.size(), ELFHeader_e_shnum_Offset);
-
- // Now that we know the offset in the file of the section table (which we emit
- // next), update the e_shoff address in the ELF header.
- fixaddr(OutputBuffer.size(), ELFHeader_e_shoff_Offset);
-
- // Emit all of the section table entries.
- for (unsigned i = 0, e = SectionList.size(); i != e; ++i) {
- const ELFSection &S = SectionList[i];
- outword(S.NameIdx); // sh_name - Symbol table name idx
- outword(S.Type); // sh_type - Section contents & semantics
- outword(S.Flags); // sh_flags - Section flags.
- outaddr(S.Addr); // sh_addr - The mem address this section appears in.
- outaddr(S.Offset); // sh_offset - The offset from the start of the file.
- outword(S.Size); // sh_size - The section size.
- outword(S.Link); // sh_link - Section header table index link.
- outword(S.Info); // sh_info - Auxillary information.
- outword(S.Align); // sh_addralign - Alignment of section.
- outword(S.EntSize); // sh_entsize - Size of each entry in the section.
+/// OutputSectionsAndSectionTable - Now that we have constructed the file header
+/// and all of the sections, emit these to the ostream destination and emit the
+/// SectionTable.
+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;
+ continue;
+ }
+
+ // Update Section size
+ if (!I->Size)
+ I->Size = I->size();
+
+ // Align FileOff to whatever the alignment restrictions of the section are.
+ if (I->Align)
+ FileOff = (FileOff+I->Align-1) & ~(I->Align-1);
+
+ I->Offset = FileOff;
+ FileOff += I->Size;
+ }
+
+ // Align Section Header.
+ unsigned TableAlign = TEW->getPrefELFAlignment();
+ FileOff = (FileOff+TableAlign-1) & ~(TableAlign-1);
+
+ // Now that we know where all of the sections will be emitted, set the e_shnum
+ // entry in the ELF header.
+ ElfHdr.fixWord16(NumSections, ELFHdr_e_shnum_Offset);
+
+ // Now that we know the offset in the file of the section table, update the
+ // e_shoff address in the ELF header.
+ ElfHdr.fixWord(FileOff, ELFHdr_e_shoff_Offset);
+
+ // Now that we know all of the data in the file header, emit it and all of the
+ // sections!
+ O.write((char *)&ElfHdr.getData()[0], ElfHdr.size());
+ FileOff = ElfHdr.size();
+
+ // Section Header Table blob
+ 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";
+
+ // Align FileOff to whatever the alignment restrictions of the section are.
+ if (S.size()) {
+ if (S.Align) {
+ for (size_t NewFileOff = (FileOff+S.Align-1) & ~(S.Align-1);
+ FileOff != NewFileOff; ++FileOff)
+ O << (char)0xAB;
+ }
+ O.write((char *)&S.getData()[0], S.Size);
+ FileOff += S.Size;
+ }
+
+ EmitSectionHeader(SHdrTable, S);
+ SectionList.pop_front();
}
- // Release the memory allocated for the section list.
- std::vector<ELFSection>().swap(SectionList);
+ // Align output for the section table.
+ for (size_t NewFileOff = (FileOff+TableAlign-1) & ~(TableAlign-1);
+ FileOff != NewFileOff; ++FileOff)
+ O << (char)0xAB;
+
+ // Emit the section table itself.
+ O.write((char *)&SHdrTable.getData()[0], SHdrTable.size());
}
projects / oota-llvm.git / blobdiff