// ...
// #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!
-//
//===----------------------------------------------------------------------===//
+#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/Type.h" // FIXME: For PATypeHolder::get().
-#include "llvm/CodeGen/FileWriters.h"
+#include "llvm/DerivedTypes.h"
+#include "llvm/CodeGen/BinaryObject.h"
+#include "llvm/CodeGen/MachineCodeEmitter.h"
+#include "llvm/CodeGen/ObjectCodeEmitter.h"
#include "llvm/CodeGen/MachineCodeEmitter.h"
#include "llvm/CodeGen/MachineConstantPool.h"
-#include "llvm/CodeGen/MachineFunctionPass.h"
+#include "llvm/MC/MCContext.h"
+#include "llvm/MC/MCSectionELF.h"
+#include "llvm/MC/MCAsmInfo.h"
+#include "llvm/Target/Mangler.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/OutputBuffer.h"
-#include "llvm/Support/Streams.h"
+#include "llvm/Target/TargetRegisterInfo.h"
+#include "llvm/Support/Debug.h"
+#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/raw_ostream.h"
-#include <list>
+#include "llvm/ADT/SmallString.h"
using namespace llvm;
char ELFWriter::ID = 0;
-/// AddELFWriter - Concrete function to add the ELF writer to the function pass
-/// manager.
-MachineCodeEmitter *llvm::AddELFWriter(PassManagerBase &PM,
- raw_ostream &O,
- TargetMachine &TM) {
- ELFWriter *EW = new ELFWriter(O, TM);
- PM.add(EW);
- return &EW->getMachineCodeEmitter();
-}
//===----------------------------------------------------------------------===//
-// ELFCodeEmitter Implementation
+// ELFWriter Implementation
//===----------------------------------------------------------------------===//
-namespace llvm {
- /// ELFCodeEmitter - This class is used by the ELFWriter to emit the code for
- /// functions to the ELF file.
- class ELFCodeEmitter : public MachineCodeEmitter {
- ELFWriter &EW;
- TargetMachine &TM;
- ELFWriter::ELFSection *ES; // Section to write to.
- std::vector<unsigned char> *OutBuffer;
- size_t FnStart;
- public:
- explicit ELFCodeEmitter(ELFWriter &ew) : EW(ew), TM(EW.TM), OutBuffer(0) {}
-
- void startFunction(MachineFunction &F);
- bool finishFunction(MachineFunction &F);
-
- void addRelocation(const MachineRelocation &MR) {
- assert(0 && "relo not handled yet!");
- }
-
- virtual void StartMachineBasicBlock(MachineBasicBlock *MBB) {
- }
+ELFWriter::ELFWriter(raw_ostream &o, TargetMachine &tm)
+ : MachineFunctionPass(ID), O(o), TM(tm),
+ OutContext(*new MCContext(*TM.getMCAsmInfo(), *TM.getRegisterInfo(),
+ &TM.getTargetLowering()->getObjFileLowering())),
+ TLOF(TM.getTargetLowering()->getObjFileLowering()),
+ is64Bit(TM.getTargetData()->getPointerSizeInBits() == 64),
+ isLittleEndian(TM.getTargetData()->isLittleEndian()),
+ ElfHdr(isLittleEndian, is64Bit) {
- virtual uintptr_t getConstantPoolEntryAddress(unsigned Index) const {
- assert(0 && "CP not implementated yet!");
- return 0;
- }
- virtual uintptr_t getJumpTableEntryAddress(unsigned Index) const {
- assert(0 && "JT not implementated yet!");
- return 0;
- }
+ MAI = TM.getMCAsmInfo();
+ TEW = TM.getELFWriterInfo();
- virtual uintptr_t getMachineBasicBlockAddress(MachineBasicBlock *MBB) const {
- assert(0 && "JT not implementated yet!");
- return 0;
- }
+ // Create the object code emitter object for this target.
+ ElfCE = new ELFCodeEmitter(*this);
- virtual uintptr_t getLabelAddress(uint64_t Label) const {
- assert(0 && "Label address not implementated yet!");
- abort();
- return 0;
- }
+ // Initial number of sections
+ NumSections = 0;
+}
- virtual void emitLabel(uint64_t LabelID) {
- assert(0 && "emit Label not implementated yet!");
- abort();
- }
+ELFWriter::~ELFWriter() {
+ delete ElfCE;
+ delete &OutContext;
+ while(!SymbolList.empty()) {
+ delete SymbolList.back();
+ SymbolList.pop_back();
+ }
- virtual void setModuleInfo(llvm::MachineModuleInfo* MMI) { }
+ while(!PrivateSyms.empty()) {
+ delete PrivateSyms.back();
+ PrivateSyms.pop_back();
+ }
+ while(!SectionList.empty()) {
+ delete SectionList.back();
+ SectionList.pop_back();
+ }
- /// JIT SPECIFIC FUNCTIONS - DO NOT IMPLEMENT THESE HERE!
- void startGVStub(const GlobalValue* F, unsigned StubSize,
- unsigned Alignment = 1) {
- assert(0 && "JIT specific function called!");
- abort();
- }
- void *finishGVStub(const GlobalValue *F) {
- assert(0 && "JIT specific function called!");
- abort();
- return 0;
- }
- };
-}
-
-/// startFunction - This callback is invoked when a new machine function is
-/// about to be emitted.
-void ELFCodeEmitter::startFunction(MachineFunction &F) {
- // Align the output buffer to the appropriate alignment.
- unsigned Align = 16; // FIXME: GENERICIZE!!
- // Get the ELF Section that this function belongs in.
- ES = &EW.getSection(".text", ELFWriter::ELFSection::SHT_PROGBITS,
- ELFWriter::ELFSection::SHF_EXECINSTR |
- ELFWriter::ELFSection::SHF_ALLOC);
- OutBuffer = &ES->SectionData;
- cerr << "FIXME: This code needs to be updated for changes in the "
- << "CodeEmitter interfaces. In particular, this should set "
- << "BufferBegin/BufferEnd/CurBufferPtr, not deal with OutBuffer!";
- abort();
-
- // Upgrade the section alignment if required.
- if (ES->Align < Align) ES->Align = Align;
-
- // Add padding zeros to the end of the buffer to make sure that the
- // function will start on the correct byte alignment within the section.
- OutputBuffer OB(*OutBuffer,
- TM.getTargetData()->getPointerSizeInBits() == 64,
- TM.getTargetData()->isLittleEndian());
- OB.align(Align);
- FnStart = OutBuffer->size();
-}
-
-/// finishFunction - This callback is invoked after the function is completely
-/// finished.
-bool ELFCodeEmitter::finishFunction(MachineFunction &F) {
- // We now know the size of the function, add a symbol to represent it.
- ELFWriter::ELFSym FnSym(F.getFunction());
-
- // Figure out the binding (linkage) of the symbol.
- switch (F.getFunction()->getLinkage()) {
- default:
- // appending linkage is illegal for functions.
- assert(0 && "Unknown linkage type!");
- case GlobalValue::ExternalLinkage:
- FnSym.SetBind(ELFWriter::ELFSym::STB_GLOBAL);
- break;
- case GlobalValue::LinkOnceLinkage:
- case GlobalValue::WeakLinkage:
- FnSym.SetBind(ELFWriter::ELFSym::STB_WEAK);
- break;
- case GlobalValue::InternalLinkage:
- FnSym.SetBind(ELFWriter::ELFSym::STB_LOCAL);
+ // Release the name mangler object.
+ delete Mang; Mang = 0;
+}
+
+// doInitialization - Emit the file header and all of the global variables for
+// the module to the ELF file.
+bool ELFWriter::doInitialization(Module &M) {
+ // Initialize TargetLoweringObjectFile.
+ const_cast<TargetLoweringObjectFile&>(TLOF).Initialize(OutContext, TM);
+
+ Mang = new Mangler(OutContext, *TM.getTargetData());
+
+ // 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(ELF::EV_CURRENT); // e_ident[EI_VERSION]
+ ElfHdr.emitAlignment(16); // e_ident[EI_NIDENT-EI_PAD]
+
+ ElfHdr.emitWord16(ELF::ET_REL); // e_type
+ ElfHdr.emitWord16(TEW->getEMachine()); // e_machine = target
+ ElfHdr.emitWord32(ELF::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();
+
+ // The first entry in the symtab is the null symbol and the second
+ // is a local symbol containing the module/file name
+ SymbolList.push_back(new ELFSym());
+ SymbolList.push_back(ELFSym::getFileSym());
+
+ return false;
+}
+
+// AddPendingGlobalSymbol - Add a global to be processed and to
+// the global symbol lookup, use a zero index because the table
+// index will be determined later.
+void ELFWriter::AddPendingGlobalSymbol(const GlobalValue *GV,
+ bool AddToLookup /* = false */) {
+ PendingGlobals.insert(GV);
+ if (AddToLookup)
+ GblSymLookup[GV] = 0;
+}
+
+// AddPendingExternalSymbol - Add the external to be processed
+// and to the external symbol lookup, use a zero index because
+// the symbol table index will be determined later.
+void ELFWriter::AddPendingExternalSymbol(const char *External) {
+ PendingExternals.insert(External);
+ ExtSymLookup[External] = 0;
+}
+
+ELFSection &ELFWriter::getDataSection() {
+ const MCSectionELF *Data = (const MCSectionELF *)TLOF.getDataSection();
+ return getSection(Data->getSectionName(), Data->getType(),
+ Data->getFlags(), 4);
+}
+
+ELFSection &ELFWriter::getBSSSection() {
+ const MCSectionELF *BSS = (const MCSectionELF *)TLOF.getBSSSection();
+ return getSection(BSS->getSectionName(), BSS->getType(), BSS->getFlags(), 4);
+}
+
+// getCtorSection - Get the static constructor section
+ELFSection &ELFWriter::getCtorSection() {
+ const MCSectionELF *Ctor = (const MCSectionELF *)TLOF.getStaticCtorSection();
+ return getSection(Ctor->getSectionName(), Ctor->getType(), Ctor->getFlags());
+}
+
+// getDtorSection - Get the static destructor section
+ELFSection &ELFWriter::getDtorSection() {
+ const MCSectionELF *Dtor = (const MCSectionELF *)TLOF.getStaticDtorSection();
+ return getSection(Dtor->getSectionName(), Dtor->getType(), Dtor->getFlags());
+}
+
+// getTextSection - Get the text section for the specified function
+ELFSection &ELFWriter::getTextSection(const Function *F) {
+ const MCSectionELF *Text =
+ (const MCSectionELF *)TLOF.SectionForGlobal(F, Mang, TM);
+ return getSection(Text->getSectionName(), Text->getType(), Text->getFlags());
+}
+
+// getJumpTableSection - Get a read only section for constants when
+// emitting jump tables. TODO: add PIC support
+ELFSection &ELFWriter::getJumpTableSection() {
+ const MCSectionELF *JT =
+ (const MCSectionELF *)TLOF.getSectionForConstant(SectionKind::getReadOnly());
+ return getSection(JT->getSectionName(), JT->getType(), JT->getFlags(),
+ TM.getTargetData()->getPointerABIAlignment());
+}
+
+// getConstantPoolSection - Get a constant pool section based on the machine
+// constant pool entry type and relocation info.
+ELFSection &ELFWriter::getConstantPoolSection(MachineConstantPoolEntry &CPE) {
+ SectionKind Kind;
+ switch (CPE.getRelocationInfo()) {
+ default: llvm_unreachable("Unknown section kind");
+ case 2: Kind = SectionKind::getReadOnlyWithRel(); break;
+ case 1:
+ Kind = SectionKind::getReadOnlyWithRelLocal();
break;
+ case 0:
+ switch (TM.getTargetData()->getTypeAllocSize(CPE.getType())) {
+ case 4: Kind = SectionKind::getMergeableConst4(); break;
+ case 8: Kind = SectionKind::getMergeableConst8(); break;
+ case 16: Kind = SectionKind::getMergeableConst16(); break;
+ default: Kind = SectionKind::getMergeableConst(); break;
+ }
}
- ES->Size = OutBuffer->size();
+ const MCSectionELF *CPSect =
+ (const MCSectionELF *)TLOF.getSectionForConstant(Kind);
+ return getSection(CPSect->getSectionName(), CPSect->getType(),
+ CPSect->getFlags(), CPE.getAlignment());
+}
- FnSym.SetType(ELFWriter::ELFSym::STT_FUNC);
- FnSym.SectionIdx = ES->SectionIdx;
- FnSym.Value = FnStart; // Value = Offset from start of Section.
- FnSym.Size = OutBuffer->size()-FnStart;
+// getRelocSection - Return the relocation section of section 'S'. 'RelA'
+// is true if the relocation section contains entries with addends.
+ELFSection &ELFWriter::getRelocSection(ELFSection &S) {
+ unsigned SectionType = TEW->hasRelocationAddend() ?
+ ELF::SHT_RELA : ELF::SHT_REL;
- // Finally, add it to the symtab.
- EW.SymbolTable.push_back(FnSym);
- return false;
+ std::string SectionName(".rel");
+ if (TEW->hasRelocationAddend())
+ SectionName.append("a");
+ SectionName.append(S.getName());
+
+ return getSection(SectionName, SectionType, 0, TEW->getPrefELFAlignment());
}
-//===----------------------------------------------------------------------===//
-// ELFWriter Implementation
-//===----------------------------------------------------------------------===//
+// getGlobalELFVisibility - Returns the ELF specific visibility type
+unsigned ELFWriter::getGlobalELFVisibility(const GlobalValue *GV) {
+ switch (GV->getVisibility()) {
+ default:
+ llvm_unreachable("unknown visibility type");
+ case GlobalValue::DefaultVisibility:
+ return ELF::STV_DEFAULT;
+ case GlobalValue::HiddenVisibility:
+ return ELF::STV_HIDDEN;
+ case GlobalValue::ProtectedVisibility:
+ return ELF::STV_PROTECTED;
+ }
+ return 0;
+}
-ELFWriter::ELFWriter(raw_ostream &o, TargetMachine &tm)
- : MachineFunctionPass(&ID), O(o), TM(tm) {
- e_flags = 0; // e_flags defaults to 0, no flags.
+// getGlobalELFBinding - Returns the ELF specific binding type
+unsigned ELFWriter::getGlobalELFBinding(const GlobalValue *GV) {
+ if (GV->hasInternalLinkage())
+ return ELF::STB_LOCAL;
- is64Bit = TM.getTargetData()->getPointerSizeInBits() == 64;
- isLittleEndian = TM.getTargetData()->isLittleEndian();
+ if (GV->isWeakForLinker() && !GV->hasCommonLinkage())
+ return ELF::STB_WEAK;
- // Create the machine code emitter object for this target.
- MCE = new ELFCodeEmitter(*this);
- NumSections = 0;
+ return ELF::STB_GLOBAL;
}
-ELFWriter::~ELFWriter() {
- delete MCE;
+// getGlobalELFType - Returns the ELF specific type for a global
+unsigned ELFWriter::getGlobalELFType(const GlobalValue *GV) {
+ if (GV->isDeclaration())
+ return ELF::STT_NOTYPE;
+
+ if (isa<Function>(GV))
+ return ELF::STT_FUNC;
+
+ return ELF::STT_OBJECT;
}
-// doInitialization - Emit the file header and all of the global variables for
-// the module to the ELF file.
-bool ELFWriter::doInitialization(Module &M) {
- Mang = new Mangler(M);
-
- // Local alias to shortenify coming code.
- std::vector<unsigned char> &FH = FileHeader;
- OutputBuffer FHOut(FH, is64Bit, isLittleEndian);
-
- FHOut.outbyte(0x7F); // EI_MAG0
- FHOut.outbyte('E'); // EI_MAG1
- FHOut.outbyte('L'); // EI_MAG2
- FHOut.outbyte('F'); // EI_MAG3
- FHOut.outbyte(is64Bit ? 2 : 1); // EI_CLASS
- FHOut.outbyte(isLittleEndian ? 1 : 2); // EI_DATA
- FHOut.outbyte(1); // EI_VERSION
- FH.resize(16); // EI_PAD up to 16 bytes.
-
- // This should change for shared objects.
- FHOut.outhalf(1); // e_type = ET_REL
- FHOut.outhalf(TM.getELFWriterInfo()->getEMachine()); // target-defined
- FHOut.outword(1); // e_version = 1
- FHOut.outaddr(0); // e_entry = 0 -> no entry point in .o file
- FHOut.outaddr(0); // e_phoff = 0 -> no program header for .o
-
- ELFHeader_e_shoff_Offset = FH.size();
- FHOut.outaddr(0); // e_shoff
- FHOut.outword(e_flags); // e_flags = whatever the target wants
-
- FHOut.outhalf(is64Bit ? 64 : 52); // e_ehsize = ELF header size
- FHOut.outhalf(0); // e_phentsize = prog header entry size
- FHOut.outhalf(0); // e_phnum = # prog header entries = 0
- FHOut.outhalf(is64Bit ? 64 : 40); // e_shentsize = sect hdr entry size
-
-
- ELFHeader_e_shnum_Offset = FH.size();
- FHOut.outhalf(0); // e_shnum = # of section header ents
- ELFHeader_e_shstrndx_Offset = FH.size();
- FHOut.outhalf(0); // e_shstrndx = Section # of '.shstrtab'
+// 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));
+}
- // Add the null section, which is required to be first in the file.
- getSection("", 0, 0);
+// AddToSymbolList - Update the symbol lookup and If the symbol is
+// private add it to PrivateSyms list, otherwise to SymbolList.
+void ELFWriter::AddToSymbolList(ELFSym *GblSym) {
+ assert(GblSym->isGlobalValue() && "Symbol must be a global value");
+
+ const GlobalValue *GV = GblSym->getGlobalValue();
+ if (GV->hasPrivateLinkage()) {
+ // For a private symbols, keep track of the index inside
+ // the private list since it will never go to the symbol
+ // table and won't be patched up later.
+ PrivateSyms.push_back(GblSym);
+ GblSymLookup[GV] = PrivateSyms.size()-1;
+ } else {
+ // 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;
+ }
+}
- // Start up the symbol table. The first entry in the symtab is the null
- // entry.
- SymbolTable.push_back(ELFSym(0));
+/// HasCommonSymbols - True if this section holds common symbols, this is
+/// indicated on the ELF object file by a symbol with SHN_COMMON section
+/// header index.
+static bool HasCommonSymbols(const MCSectionELF &S) {
+ // FIXME: this is wrong, a common symbol can be in .data for example.
+ if (StringRef(S.getSectionName()).startswith(".gnu.linkonce."))
+ return true;
return false;
}
-void ELFWriter::EmitGlobal(GlobalVariable *GV) {
- // If this is an external global, emit it now. TODO: Note that it would be
- // better to ignore the symbol here and only add it to the symbol table if
- // referenced.
- if (!GV->hasInitializer()) {
- ELFSym ExternalSym(GV);
- ExternalSym.SetBind(ELFSym::STB_GLOBAL);
- ExternalSym.SetType(ELFSym::STT_NOTYPE);
- ExternalSym.SectionIdx = ELFSection::SHN_UNDEF;
- SymbolTable.push_back(ExternalSym);
+
+// 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;
- }
- const Type *GVType = (const Type*)GV->getType();
- unsigned Align = TM.getTargetData()->getPreferredAlignment(GV);
- unsigned Size = TM.getTargetData()->getABITypeSize(GVType);
-
- // 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() ||
- GV->hasCommonLinkage()) {
- ELFSym CommonSym(GV);
- // Value for common symbols is the alignment required.
- CommonSym.Value = Align;
- CommonSym.Size = Size;
- CommonSym.SetBind(ELFSym::STB_GLOBAL);
- CommonSym.SetType(ELFSym::STT_OBJECT);
- // TODO SOMEDAY: add ELF visibility.
- CommonSym.SectionIdx = ELFSection::SHN_COMMON;
- SymbolTable.push_back(CommonSym);
+ // Handle ELF Bind, Visibility and Type for the current symbol
+ unsigned SymBind = getGlobalELFBinding(GV);
+ unsigned SymType = getGlobalELFType(GV);
+ bool IsUndefSym = IsELFUndefSym(GV);
+
+ ELFSym *GblSym = IsUndefSym ? ELFSym::getUndefGV(GV, SymBind)
+ : ELFSym::getGV(GV, SymBind, SymType, getGlobalELFVisibility(GV));
+
+ if (!IsUndefSym) {
+ assert(isa<GlobalVariable>(GV) && "GV not a global variable!");
+ const GlobalVariable *GVar = dyn_cast<GlobalVariable>(GV);
+
+ // Handle special llvm globals
+ if (EmitSpecialLLVMGlobal(GVar))
return;
- }
- // Otherwise, this symbol is part of the .bss section. Emit it now.
-
- // Handle alignment. Ensure section is aligned at least as much as required
- // by this symbol.
- ELFSection &BSSSection = getBSSSection();
- BSSSection.Align = std::max(BSSSection.Align, Align);
-
- // Within the section, emit enough virtual padding to get us to an alignment
- // boundary.
- if (Align)
- BSSSection.Size = (BSSSection.Size + Align - 1) & ~(Align-1);
-
- ELFSym BSSSym(GV);
- BSSSym.Value = BSSSection.Size;
- BSSSym.Size = Size;
- BSSSym.SetType(ELFSym::STT_OBJECT);
-
- switch (GV->getLinkage()) {
- default: // weak/linkonce/common handled above
- assert(0 && "Unexpected linkage type!");
- case GlobalValue::AppendingLinkage: // FIXME: This should be improved!
- case GlobalValue::ExternalLinkage:
- BSSSym.SetBind(ELFSym::STB_GLOBAL);
- break;
- case GlobalValue::InternalLinkage:
- BSSSym.SetBind(ELFSym::STB_LOCAL);
- break;
+ // Get the ELF section where this global belongs from TLOF
+ const MCSectionELF *S =
+ (const MCSectionELF *)TLOF.SectionForGlobal(GV, Mang, TM);
+ ELFSection &ES =
+ getSection(S->getSectionName(), S->getType(), S->getFlags());
+ SectionKind Kind = S->getKind();
+
+ // The symbol align should update the section alignment if needed
+ const TargetData *TD = TM.getTargetData();
+ unsigned Align = TD->getPreferredAlignment(GVar);
+ unsigned Size = TD->getTypeAllocSize(GVar->getInitializer()->getType());
+ GblSym->Size = Size;
+
+ if (HasCommonSymbols(*S)) { // Symbol must go to a common section
+ GblSym->SectionIdx = ELF::SHN_COMMON;
+
+ // A new linkonce section is created for each global in the
+ // common section, the default alignment is 1 and the symbol
+ // value contains its alignment.
+ ES.Align = 1;
+ GblSym->Value = Align;
+
+ } else if (Kind.isBSS() || Kind.isThreadBSS()) { // Symbol goes to BSS.
+ GblSym->SectionIdx = ES.SectionIdx;
+
+ // Update the size with alignment and the next object can
+ // start in the right offset in the section
+ if (Align) ES.Size = (ES.Size + Align-1) & ~(Align-1);
+ ES.Align = std::max(ES.Align, Align);
+
+ // GblSym->Value should contain the virtual offset inside the section.
+ // Virtual because the BSS space is not allocated on ELF objects
+ GblSym->Value = ES.Size;
+ ES.Size += Size;
+
+ } else { // The symbol must go to some kind of data section
+ GblSym->SectionIdx = ES.SectionIdx;
+
+ // GblSym->Value should contain the symbol offset inside the section,
+ // and all symbols should start on their required alignment boundary
+ ES.Align = std::max(ES.Align, Align);
+ ES.emitAlignment(Align);
+ GblSym->Value = ES.size();
+
+ // Emit the global to the data section 'ES'
+ EmitGlobalConstant(GVar->getInitializer(), ES);
}
+ }
+
+ AddToSymbolList(GblSym);
+}
+
+void ELFWriter::EmitGlobalConstantStruct(const ConstantStruct *CVS,
+ 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.
+ GblS.emitZeros(padSize);
+ }
+ assert(sizeSoFar == cvsLayout->getSizeInBytes() &&
+ "Layout of constant struct may be incorrect!");
+}
+
+void ELFWriter::EmitGlobalConstant(const Constant *CV, ELFSection &GblS) {
+ const TargetData *TD = TM.getTargetData();
+ unsigned Size = TD->getTypeAllocSize(CV->getType());
- // Set the idx of the .bss section
- BSSSym.SectionIdx = BSSSection.SectionIdx;
- SymbolTable.push_back(BSSSym);
+ if (const ConstantArray *CVA = dyn_cast<ConstantArray>(CV)) {
+ 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)) {
+ APInt Val = CFP->getValueAPF().bitcastToAPInt();
+ if (CFP->getType()->isDoubleTy())
+ GblS.emitWord64(Val.getZExtValue());
+ else if (CFP->getType()->isFloatTy())
+ GblS.emitWord32(Val.getZExtValue());
+ else if (CFP->getType()->isX86_FP80Ty()) {
+ unsigned PadSize = TD->getTypeAllocSize(CFP->getType())-
+ TD->getTypeStoreSize(CFP->getType());
+ GblS.emitWordFP80(Val.getRawData(), PadSize);
+ } else if (CFP->getType()->isPPC_FP128Ty())
+ llvm_unreachable("PPC_FP128Ty global emission not implemented");
+ return;
+ } else if (const ConstantInt *CI = dyn_cast<ConstantInt>(CV)) {
+ if (Size == 1)
+ GblS.emitByte(CI->getZExtValue());
+ else if (Size == 2)
+ GblS.emitWord16(CI->getZExtValue());
+ else if (Size == 4)
+ GblS.emitWord32(CI->getZExtValue());
+ else
+ EmitGlobalConstantLargeInt(CI, GblS);
+ return;
+ } else if (const ConstantVector *CP = dyn_cast<ConstantVector>(CV)) {
+ 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);
- // Reserve space in the .bss section for this symbol.
- BSSSection.Size += Size;
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();
+ report_fatal_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);
+ 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);
+ Type *Ty = CE->getType();
+
+ // We can emit the pointer value into this slot if the slot is an
+ // integer slot greater or equal to the size of the pointer.
+ if (TD->getTypeAllocSize(Ty) == TD->getTypeAllocSize(Op->getType()))
+ return ResolveConstantExpr(Op);
+
+ llvm_unreachable("Integer size less then pointer size");
}
+ case Instruction::Add:
+ case Instruction::Sub: {
+ // Only handle cases where there's a constant expression with GlobalValue
+ // as first operand and ConstantInt as second, which are the cases we can
+ // solve direclty using a relocation entry. GlobalValue=Op0, CstInt=Op1
+ // 1) Instruction::Add => (global) + CstInt
+ // 2) Instruction::Sub => (global) + -CstInt
+ const Constant *Op0 = CE->getOperand(0);
+ const Constant *Op1 = CE->getOperand(1);
+ assert(isa<ConstantInt>(Op1) && "Op1 must be a ConstantInt");
+
+ CstExprResTy Res = ResolveConstantExpr(Op0);
+ assert(isa<GlobalValue>(Res.first) && "Op0 must be a GlobalValue");
+
+ const APInt &RHS = cast<ConstantInt>(Op1)->getValue();
+ switch (CE->getOpcode()) {
+ case Instruction::Add:
+ return std::make_pair(Res.first, RHS.getSExtValue());
+ case Instruction::Sub:
+ return std::make_pair(Res.first, (-RHS).getSExtValue());
+ }
+ }
+ }
+
+ report_fatal_error(CE->getOpcodeName() +
+ StringRef(": Unsupported ConstantExpr type"));
+
+ return std::make_pair(CV, 0); // silence warning
+}
- // FIXME: handle .rodata
- //assert(!GV->isConstant() && "unimp");
+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);
- // FIXME: handle .data
- //assert(0 && "unimp");
+ // 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(const Constant *List, ELFSection &Xtor) {
+ // Should be an array of '{ i32, void ()* }' structs. The first value is the
+ // init priority, which we ignore.
+ if (List->isNullValue()) return;
+ const ConstantArray *InitList = cast<ConstantArray>(List);
+ for (unsigned i = 0, e = InitList->getNumOperands(); i != e; ++i) {
+ if (InitList->getOperand(i)->isNullValue())
+ continue;
+ ConstantStruct *CS = cast<ConstantStruct>(InitList->getOperand(i));
+
+ if (CS->getOperand(1)->isNullValue())
+ continue;
+
+ // Emit the function pointer.
+ EmitGlobalConstant(CS->getOperand(1), Xtor);
+ }
+}
bool ELFWriter::runOnMachineFunction(MachineFunction &MF) {
- // Nothing to do here, this is all done through the MCE object above.
+ // Nothing to do here, this is all done through the ElfCE object above.
return false;
}
/// doFinalization - Now that the module has been completely processed, emit
/// the ELF file to 'O'.
bool ELFWriter::doFinalization(Module &M) {
- // Okay, the ELF header and .text sections have been completed, build the
- // .data, .bss, and "common" sections next.
+ // 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);
+ // Emit all pending globals
+ 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 a symbol for each section created until now, skip null section
+ for (unsigned i = 1, e = SectionList.size(); i < e; ++i) {
+ ELFSection &ES = *SectionList[i];
+ ELFSym *SectionSym = ELFSym::getSectionSym();
+ SectionSym->SectionIdx = ES.SectionIdx;
+ SymbolList.push_back(SectionSym);
+ ES.Sym = SymbolList.back();
+ }
+
+ // Emit string table
+ EmitStringTable(M.getModuleIdentifier());
+
// 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 sections to the .o file, and emit the section table for the file.
+ // Dump the sections and section table to the .o file.
OutputSectionsAndSectionTable();
- // We are done with the abstract symbols.
- SectionList.clear();
- NumSections = 0;
-
- // Release the name mangler object.
- delete Mang; Mang = 0;
return false;
}
-/// 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.
+// 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 (unsigned i=0, e=SectionList.size(); i != e; ++i) {
+ ELFSection &S = *SectionList[i];
+
+ // This section does not have relocations
+ 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 = S.SectionIdx;
+ RelSec.EntSize = TEW->getRelocationEntrySize();
+
+ // Get the relocations from Section
+ std::vector<MachineRelocation> Relos = S.getRelocations();
+ for (std::vector<MachineRelocation>::iterator MRI = Relos.begin(),
+ MRE = Relos.end(); MRI != MRE; ++MRI) {
+ MachineRelocation &MR = *MRI;
+
+ // Relocatable field offset from the section start
+ unsigned RelOffset = MR.getMachineCodeOffset();
+
+ // Symbol index in the symbol table
+ unsigned SymIdx = 0;
+
+ // Target specific relocation field type and size
+ unsigned RelType = TEW->getRelocationType(MR.getRelocationType());
+ unsigned RelTySize = TEW->getRelocationTySize(RelType);
+ int64_t Addend = 0;
+
+ // There are several machine relocations types, and each one of
+ // them needs a different approach to retrieve the symbol table index.
+ if (MR.isGlobalValue()) {
+ const GlobalValue *G = MR.getGlobalValue();
+ int64_t GlobalOffset = MR.getConstantVal();
+ SymIdx = GblSymLookup[G];
+ if (G->hasPrivateLinkage()) {
+ // If the target uses a section offset in the relocation:
+ // SymIdx + Addend = section sym for global + section offset
+ unsigned SectionIdx = PrivateSyms[SymIdx]->SectionIdx;
+ Addend = PrivateSyms[SymIdx]->Value + GlobalOffset;
+ SymIdx = SectionList[SectionIdx]->getSymbolTableIndex();
+ } else {
+ Addend = TEW->getDefaultAddendForRelTy(RelType, GlobalOffset);
+ }
+ } else if (MR.isExternalSymbol()) {
+ const char *ExtSym = MR.getExternalSymbol();
+ SymIdx = ExtSymLookup[ExtSym];
+ Addend = TEW->getDefaultAddendForRelTy(RelType);
+ } else {
+ // Get the symbol index for the section symbol
+ unsigned SectionIdx = MR.getConstantVal();
+ SymIdx = SectionList[SectionIdx]->getSymbolTableIndex();
+
+ // The symbol offset inside the section
+ int64_t SymOffset = (int64_t)MR.getResultPointer();
+
+ // For pc relative relocations where symbols are defined in the same
+ // section they are referenced, ignore the relocation entry and patch
+ // the relocatable field with the symbol offset directly.
+ if (S.SectionIdx == SectionIdx && TEW->isPCRelativeRel(RelType)) {
+ int64_t Value = TEW->computeRelocation(SymOffset, RelOffset, RelType);
+ RelocateField(S, RelOffset, Value, RelTySize);
+ continue;
+ }
+
+ Addend = TEW->getDefaultAddendForRelTy(RelType, SymOffset);
+ }
+
+ // The target without addend on the relocation symbol must be
+ // patched in the relocation place itself to contain the addend
+ // otherwise write zeros to make sure there is no garbage there
+ RelocateField(S, RelOffset, HasRelA ? 0 : Addend, RelTySize);
+
+ // Get the relocation entry and emit to the relocation section
+ ELFRelocation Rel(RelOffset, 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);
+ }
+}
- ELFSection &StrTab = getSection(".strtab", ELFSection::SHT_STRTAB, 0);
- StrTab.Align = 1;
+/// 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);
+ }
+}
- DataBuffer &StrTabBuf = StrTab.SectionData;
- OutputBuffer StrTabOut(StrTabBuf, is64Bit, isLittleEndian);
+/// EmitStringTable - If the current symbol table is non-empty, emit the string
+/// table for it
+void ELFWriter::EmitStringTable(const std::string &ModuleName) {
+ if (!SymbolList.size()) return; // Empty symbol table.
+ ELFSection &StrTab = getStringTableSection();
// Set the zero'th symbol to a null byte, as required.
- StrTabOut.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) {
- // Use the name mangler to uniquify the LLVM symbol.
- std::string Name = Mang->getValueName(SymbolTable[i].GV);
+ for (ELFSymIter I=SymbolList.begin(), E=SymbolList.end(); I != E; ++I) {
+ ELFSym &Sym = *(*I);
+
+ std::string Name;
+ if (Sym.isGlobalValue()) {
+ SmallString<40> NameStr;
+ Mang->getNameWithPrefix(NameStr, Sym.getGlobalValue(), false);
+ Name.append(NameStr.begin(), NameStr.end());
+ } else if (Sym.isExternalSym())
+ Name.append(Sym.getExternalSymbol());
+ else if (Sym.isFileType())
+ Name.append(ModuleName);
if (Name.empty()) {
- SymbolTable[i].NameIdx = 0;
+ Sym.NameIdx = 0;
} else {
- SymbolTable[i].NameIdx = Index;
-
- // Add the name to the output buffer, including the null terminator.
- StrTabBuf.insert(StrTabBuf.end(), Name.begin(), Name.end());
-
- // Add a null terminator.
- StrTabBuf.push_back(0);
+ Sym.NameIdx = Index;
+ StrTab.emitString(Name);
// Keep track of the number of bytes emitted to this section.
Index += Name.size()+1;
}
}
- assert(Index == StrTabBuf.size());
+ assert(Index == StrTab.size());
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.
// 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 = getSection(".symtab", ELFSection::SHT_SYMTAB, 0);
- SymTab.Align = is64Bit ? 8 : 4;
- SymTab.Link = SymTab.SectionIdx; // Section Index of .strtab.
- SymTab.Info = FirstNonLocalSymbol; // First non-STB_LOCAL symbol.
- SymTab.EntSize = 16; // Size of each symtab entry. FIXME: wrong for ELF64
- DataBuffer &SymTabBuf = SymTab.SectionData;
- OutputBuffer SymTabOut(SymTabBuf, is64Bit, isLittleEndian);
-
- if (!is64Bit) { // 32-bit and 64-bit formats are shuffled a bit.
- for (unsigned i = 0, e = SymbolTable.size(); i != e; ++i) {
- ELFSym &Sym = SymbolTable[i];
- SymTabOut.outword(Sym.NameIdx);
- SymTabOut.outaddr32(Sym.Value);
- SymTabOut.outword(Sym.Size);
- SymTabOut.outbyte(Sym.Info);
- SymTabOut.outbyte(Sym.Other);
- SymTabOut.outhalf(Sym.SectionIdx);
- }
- } else {
- for (unsigned i = 0, e = SymbolTable.size(); i != e; ++i) {
- ELFSym &Sym = SymbolTable[i];
- SymTabOut.outword(Sym.NameIdx);
- SymTabOut.outbyte(Sym.Info);
- SymTabOut.outbyte(Sym.Other);
- SymTabOut.outhalf(Sym.SectionIdx);
- SymTabOut.outaddr64(Sym.Value);
- SymTabOut.outxword(Sym.Size);
- }
+ ELFSection &SymTab = getSymbolTableSection();
+ SymTab.Align = TEW->getPrefELFAlignment();
+
+ // Section Index of .strtab.
+ SymTab.Link = getStringTableSection().SectionIdx;
+
+ // Size of each symtab entry.
+ SymTab.EntSize = TEW->getSymTabEntrySize();
+
+ // 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, Sym);
+
+ // 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;
}
- SymTab.Size = SymTabBuf.size();
+ // One greater than the symbol table index of the last local symbol
+ 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:
- ELFSection &SHStrTab = getSection(".shstrtab", ELFSection::SHT_STRTAB, 0);
+ ELFSection &SHStrTab = getSectionHeaderStringTableSection();
// Now that we know which section number is the .shstrtab section, update the
// e_shstrndx entry in the ELF header.
- OutputBuffer FHOut(FileHeader, is64Bit, isLittleEndian);
- FHOut.fixhalf(SHStrTab.SectionIdx, 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;
- DataBuffer &Buf = SHStrTab.SectionData;
- 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;
-
- // Add the name to the output buffer, including the null terminator.
- Buf.insert(Buf.end(), I->Name.begin(), I->Name.end());
-
- // Add a null terminator.
- Buf.push_back(0);
+ S.NameIdx = Index;
+ SHStrTab.emitString(S.getName());
// Keep track of the number of bytes emitted to this section.
- Index += I->Name.size()+1;
+ Index += S.getName().size()+1;
}
// Set the size of .shstrtab now that we know what it is.
- assert(Index == Buf.size());
+ assert(Index == SHStrTab.size());
SHStrTab.Size = Index;
}
/// SectionTable.
void ELFWriter::OutputSectionsAndSectionTable() {
// Pass #1: Compute the file offset for each section.
- size_t FileOff = FileHeader.size(); // File header first.
+ size_t FileOff = ElfHdr.size(); // File header first.
+
+ // 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 (!ES.Size)
+ ES.Size = ES.size();
- // Emit all of the section data in order.
- for (std::list<ELFSection>::iterator I = SectionList.begin(),
- E = SectionList.end(); I != E; ++I) {
// 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->SectionData.size();
+ if (ES.Align)
+ FileOff = (FileOff+ES.Align-1) & ~(ES.Align-1);
+
+ ES.Offset = FileOff;
+ FileOff += ES.Size;
}
// Align Section Header.
- unsigned TableAlign = is64Bit ? 8 : 4;
+ 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.
- OutputBuffer FHOut(FileHeader, is64Bit, isLittleEndian);
- FHOut.fixhalf(NumSections, ELFHeader_e_shnum_Offset);
+ 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.
- FHOut.fixaddr(FileOff, ELFHeader_e_shoff_Offset);
+ 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*)&FileHeader[0], FileHeader.size());
- FileOff = FileHeader.size();
- DataBuffer().swap(FileHeader);
+ O.write((char *)&ElfHdr.getData()[0], ElfHdr.size());
+ FileOff = ElfHdr.size();
- DataBuffer Table;
- OutputBuffer TableOut(Table, is64Bit, isLittleEndian);
+ // Section Header Table blob
+ BinaryObject SHdrTable(isLittleEndian, is64Bit);
- // Emit all of the section data and build the section table itself.
- while (!SectionList.empty()) {
- const ELFSection &S = *SectionList.begin();
+ // Emit all of sections to the file and build the section header table.
+ for (ELFSectionIter I=SectionList.begin(), E=SectionList.end(); I != E; ++I) {
+ ELFSection &S = *(*I);
+ DEBUG(dbgs() << "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.Align)
- for (size_t NewFileOff = (FileOff+S.Align-1) & ~(S.Align-1);
- FileOff != NewFileOff; ++FileOff)
- O << (char)0xAB;
- O.write((char*)&S.SectionData[0], S.SectionData.size());
- FileOff += S.SectionData.size();
-
- TableOut.outword(S.NameIdx); // sh_name - Symbol table name idx
- TableOut.outword(S.Type); // sh_type - Section contents & semantics
- TableOut.outword(S.Flags); // sh_flags - Section flags.
- TableOut.outaddr(S.Addr); // sh_addr - The mem addr this section is in.
- TableOut.outaddr(S.Offset); // sh_offset - Offset from the file start.
- TableOut.outword(S.Size); // sh_size - The section size.
- TableOut.outword(S.Link); // sh_link - Section header table index link.
- TableOut.outword(S.Info); // sh_info - Auxillary information.
- TableOut.outword(S.Align); // sh_addralign - Alignment of section.
- TableOut.outword(S.EntSize); // sh_entsize - Size of entries in the section
-
- SectionList.pop_front();
+ 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);
}
// Align output for the section table.
O << (char)0xAB;
// Emit the section table itself.
- O.write((char*)&Table[0], Table.size());
+ O.write((char *)&SHdrTable.getData()[0], SHdrTable.size());
}
projects / oota-llvm.git / blobdiff