#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/Support/Debug.h"
+#include "llvm/Support/ErrorHandling.h"
//===----------------------------------------------------------------------===//
// ELFCodeEmitter Implementation
/// startFunction - This callback is invoked when a new machine function is
/// about to be emitted.
void ELFCodeEmitter::startFunction(MachineFunction &MF) {
+ DOUT << "processing function: " << MF.getFunction()->getName() << "\n";
+
// Get the ELF Section that this function belongs in.
ES = &EW.getTextSection();
- DOUT << "processing function: " << MF.getFunction()->getName() << "\n";
-
- // 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.
+ // The function must start on its required alignment
+ ES->emitAlignment(Align);
+
+ // 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;
+
+ // 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 = new ELFSym(F);
+ FnSym->setType(ELFSym::STT_FUNC);
+ FnSym->setBind(EW.getGlobalELFBinding(F));
+ FnSym->setVisibility(EW.getGlobalELFVisibility(F));
+ FnSym->SectionIdx = ES->SectionIdx;
+ FnSym->Size = ES->getCurrentPCOffset()-FnStartOff;
+
+ // keep track of the emitted function leaving its symbol index as zero
+ // to be patched up later when emitting the symbol table
+ EW.setGlobalSymLookup(F, 0);
// 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.
+ 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
MR.setResultPointer((void*)Addr);
} else if (MR.isJumpTableIndex()) {
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();
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);
}
}
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);
}
}
}