diff options
Diffstat (limited to 'lib/CodeGen/ELFCodeEmitter.cpp')
| -rw-r--r-- | lib/CodeGen/ELFCodeEmitter.cpp | 155 |
1 files changed, 67 insertions, 88 deletions
diff --git a/lib/CodeGen/ELFCodeEmitter.cpp b/lib/CodeGen/ELFCodeEmitter.cpp index 691f194..a6429f7 100644 --- a/lib/CodeGen/ELFCodeEmitter.cpp +++ b/lib/CodeGen/ELFCodeEmitter.cpp @@ -17,12 +17,16 @@ #include "llvm/Function.h" #include "llvm/CodeGen/BinaryObject.h" #include "llvm/CodeGen/MachineConstantPool.h" +#include "llvm/CodeGen/MachineFunction.h" #include "llvm/CodeGen/MachineJumpTableInfo.h" #include "llvm/CodeGen/MachineRelocation.h" #include "llvm/Target/TargetData.h" +#include "llvm/Target/TargetELFWriterInfo.h" #include "llvm/Target/TargetMachine.h" -#include "llvm/Target/TargetAsmInfo.h" +#include "llvm/MC/MCAsmInfo.h" #include "llvm/Support/Debug.h" +#include "llvm/Support/ErrorHandling.h" +#include "llvm/Support/raw_ostream.h" //===----------------------------------------------------------------------===// // ELFCodeEmitter Implementation @@ -33,84 +37,75 @@ namespace llvm { /// startFunction - This callback is invoked when a new machine function is /// about to be emitted. void ELFCodeEmitter::startFunction(MachineFunction &MF) { - // Get the ELF Section that this function belongs in. - ES = &EW.getTextSection(); + DEBUG(errs() << "processing function: " + << MF.getFunction()->getName() << "\n"); - DOUT << "processing function: " << MF.getFunction()->getName() << "\n"; + // Get the ELF Section that this function belongs in. + ES = &EW.getTextSection(MF.getFunction()); - // FIXME: better memory management, this will be replaced by BinaryObjects - BinaryData &BD = ES->getData(); - BD.reserve(4096); - BufferBegin = &BD[0]; - BufferEnd = BufferBegin + BD.capacity(); + // Set the desired binary object to be used by the code emitters + setBinaryObject(ES); // Get the function alignment in bytes unsigned Align = (1 << MF.getAlignment()); - // Align the section size with the function alignment, so the function can - // start in a aligned offset, also update the section alignment if needed. - if (ES->Align < Align) ES->Align = Align; - ES->Size = (ES->Size + (Align-1)) & (-Align); - - // Snaity check on allocated space for text section - assert( ES->Size < 4096 && "no more space in TextSection" ); - - // FIXME: Using ES->Size directly here instead of calculating it from the - // output buffer size (impossible because the code emitter deals only in raw - // bytes) forces us to manually synchronize size and write padding zero bytes - // to the output buffer for all non-text sections. For text sections, we do - // not synchonize the output buffer, and we just blow up if anyone tries to - // write non-code to it. An assert should probably be added to - // AddSymbolToSection to prevent calling it on the text section. - CurBufferPtr = BufferBegin + ES->Size; - - // Record function start address relative to BufferBegin - FnStartPtr = CurBufferPtr; + // The function must start on its required alignment + ES->emitAlignment(Align); + + // Update the section alignment if needed. + ES->Align = std::max(ES->Align, Align); + + // Record the function start offset + FnStartOff = ES->getCurrentPCOffset(); + + // Emit constant pool and jump tables to their appropriate sections. + // They need to be emitted before the function because in some targets + // the later may reference JT or CP entry address. + emitConstantPool(MF.getConstantPool()); + emitJumpTables(MF.getJumpTableInfo()); } /// finishFunction - This callback is invoked after the function is completely /// finished. bool ELFCodeEmitter::finishFunction(MachineFunction &MF) { - // Update Section Size - ES->Size = CurBufferPtr - BufferBegin; - // Add a symbol to represent the function. const Function *F = MF.getFunction(); - ELFSym FnSym(F); - FnSym.setType(ELFSym::STT_FUNC); - FnSym.setBind(EW.getGlobalELFLinkage(F)); - FnSym.setVisibility(EW.getGlobalELFVisibility(F)); - FnSym.SectionIdx = ES->SectionIdx; - FnSym.Size = CurBufferPtr-FnStartPtr; + ELFSym *FnSym = ELFSym::getGV(F, EW.getGlobalELFBinding(F), ELFSym::STT_FUNC, + EW.getGlobalELFVisibility(F)); + FnSym->SectionIdx = ES->SectionIdx; + FnSym->Size = ES->getCurrentPCOffset()-FnStartOff; + EW.AddPendingGlobalSymbol(F, true); // Offset from start of Section - FnSym.Value = FnStartPtr-BufferBegin; - - // Locals should go on the symbol list front - if (!F->hasPrivateLinkage()) { - if (FnSym.getBind() == ELFSym::STB_LOCAL) - EW.SymbolList.push_front(FnSym); - else - EW.SymbolList.push_back(FnSym); + FnSym->Value = FnStartOff; + + if (!F->hasPrivateLinkage()) + EW.SymbolList.push_back(FnSym); + + // Patch up Jump Table Section relocations to use the real MBBs offsets + // now that the MBB label offsets inside the function are known. + if (!MF.getJumpTableInfo()->isEmpty()) { + ELFSection &JTSection = EW.getJumpTableSection(); + for (std::vector<MachineRelocation>::iterator MRI = JTRelocations.begin(), + MRE = JTRelocations.end(); MRI != MRE; ++MRI) { + MachineRelocation &MR = *MRI; + unsigned MBBOffset = getMachineBasicBlockAddress(MR.getBasicBlock()); + MR.setResultPointer((void*)MBBOffset); + MR.setConstantVal(ES->SectionIdx); + JTSection.addRelocation(MR); + } } - // Emit constant pool to appropriate section(s) - emitConstantPool(MF.getConstantPool()); - - // Emit jump tables to appropriate section - emitJumpTables(MF.getJumpTableInfo()); - - // Relocations - // ----------- // If we have emitted any relocations to function-specific objects such as // basic blocks, constant pools entries, or jump tables, record their - // addresses now so that we can rewrite them with the correct addresses - // later. + // addresses now so that we can rewrite them with the correct addresses later for (unsigned i = 0, e = Relocations.size(); i != e; ++i) { MachineRelocation &MR = Relocations[i]; intptr_t Addr; if (MR.isGlobalValue()) { - EW.PendingGlobals.insert(MR.getGlobalValue()); + EW.AddPendingGlobalSymbol(MR.getGlobalValue()); + } else if (MR.isExternalSymbol()) { + EW.AddPendingExternalSymbol(MR.getExternalSymbol()); } else if (MR.isBasicBlock()) { Addr = getMachineBasicBlockAddress(MR.getBasicBlock()); MR.setConstantVal(ES->SectionIdx); @@ -120,16 +115,18 @@ bool ELFCodeEmitter::finishFunction(MachineFunction &MF) { MR.setConstantVal(CPSections[MR.getConstantPoolIndex()]); MR.setResultPointer((void*)Addr); } else if (MR.isJumpTableIndex()) { + ELFSection &JTSection = EW.getJumpTableSection(); Addr = getJumpTableEntryAddress(MR.getJumpTableIndex()); + MR.setConstantVal(JTSection.SectionIdx); MR.setResultPointer((void*)Addr); - MR.setConstantVal(JumpTableSectionIdx); } else { - assert(0 && "Unhandled relocation type"); + llvm_unreachable("Unhandled relocation type"); } ES->addRelocation(MR); } // Clear per-function data structures. + JTRelocations.clear(); Relocations.clear(); CPLocations.clear(); CPSections.clear(); @@ -148,25 +145,19 @@ void ELFCodeEmitter::emitConstantPool(MachineConstantPool *MCP) { assert(TM.getRelocationModel() != Reloc::PIC_ && "PIC codegen not yet handled for elf constant pools!"); - const TargetAsmInfo *TAI = TM.getTargetAsmInfo(); for (unsigned i = 0, e = CP.size(); i != e; ++i) { MachineConstantPoolEntry CPE = CP[i]; - // Get the right ELF Section for this constant pool entry - std::string CstPoolName = - TAI->SelectSectionForMachineConst(CPE.getType())->getName(); - ELFSection &CstPoolSection = - EW.getConstantPoolSection(CstPoolName, CPE.getAlignment()); - // Record the constant pool location and the section index - CPLocations.push_back(CstPoolSection.size()); - CPSections.push_back(CstPoolSection.SectionIdx); + ELFSection &CstPool = EW.getConstantPoolSection(CPE); + CPLocations.push_back(CstPool.size()); + CPSections.push_back(CstPool.SectionIdx); if (CPE.isMachineConstantPoolEntry()) assert("CPE.isMachineConstantPoolEntry not supported yet"); // Emit the constant to constant pool section - EW.EmitGlobalConstant(CPE.Val.ConstVal, CstPoolSection); + EW.EmitGlobalConstant(CPE.Val.ConstVal, CstPool); } } @@ -180,44 +171,32 @@ void ELFCodeEmitter::emitJumpTables(MachineJumpTableInfo *MJTI) { assert(TM.getRelocationModel() != Reloc::PIC_ && "PIC codegen not yet handled for elf jump tables!"); - const TargetAsmInfo *TAI = TM.getTargetAsmInfo(); + const TargetELFWriterInfo *TEW = TM.getELFWriterInfo(); + unsigned EntrySize = MJTI->getEntrySize(); // Get the ELF Section to emit the jump table - unsigned Align = TM.getTargetData()->getPointerABIAlignment(); - std::string JTName(TAI->getJumpTableDataSection()); - ELFSection &JTSection = EW.getJumpTableSection(JTName, Align); - JumpTableSectionIdx = JTSection.SectionIdx; - - // Entries in the JT Section are relocated against the text section - ELFSection &TextSection = EW.getTextSection(); + ELFSection &JTSection = EW.getJumpTableSection(); // For each JT, record its offset from the start of the section for (unsigned i = 0, e = JT.size(); i != e; ++i) { const std::vector<MachineBasicBlock*> &MBBs = JT[i].MBBs; - DOUT << "JTSection.size(): " << JTSection.size() << "\n"; - DOUT << "JTLocations.size: " << JTLocations.size() << "\n"; - // Record JT 'i' offset in the JT section JTLocations.push_back(JTSection.size()); // Each MBB entry in the Jump table section has a relocation entry // against the current text section. for (unsigned mi = 0, me = MBBs.size(); mi != me; ++mi) { + unsigned MachineRelTy = TEW->getAbsoluteLabelMachineRelTy(); MachineRelocation MR = - MachineRelocation::getBB(JTSection.size(), - MachineRelocation::VANILLA, - MBBs[mi]); - - // Offset of JT 'i' in JT section - MR.setResultPointer((void*)getMachineBasicBlockAddress(MBBs[mi])); - MR.setConstantVal(TextSection.SectionIdx); + MachineRelocation::getBB(JTSection.size(), MachineRelTy, MBBs[mi]); // Add the relocation to the Jump Table section - JTSection.addRelocation(MR); + JTRelocations.push_back(MR); // Output placeholder for MBB in the JT section - JTSection.emitWord(0); + for (unsigned s=0; s < EntrySize; ++s) + JTSection.emitByte(0); } } } |
