diff options
Diffstat (limited to 'contrib/llvm/lib/CodeGen/AsmPrinter/AsmPrinterDwarf.cpp')
| -rw-r--r-- | contrib/llvm/lib/CodeGen/AsmPrinter/AsmPrinterDwarf.cpp | 279 |
1 files changed, 279 insertions, 0 deletions
diff --git a/contrib/llvm/lib/CodeGen/AsmPrinter/AsmPrinterDwarf.cpp b/contrib/llvm/lib/CodeGen/AsmPrinter/AsmPrinterDwarf.cpp new file mode 100644 index 0000000..b310578 --- /dev/null +++ b/contrib/llvm/lib/CodeGen/AsmPrinter/AsmPrinterDwarf.cpp @@ -0,0 +1,279 @@ +//===-- AsmPrinterDwarf.cpp - AsmPrinter Dwarf Support --------------------===// +// +// The LLVM Compiler Infrastructure +// +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// +// +// This file implements the Dwarf emissions parts of AsmPrinter. +// +//===----------------------------------------------------------------------===// + +#define DEBUG_TYPE "asm-printer" +#include "llvm/CodeGen/AsmPrinter.h" +#include "llvm/CodeGen/MachineLocation.h" +#include "llvm/MC/MCAsmInfo.h" +#include "llvm/MC/MCSection.h" +#include "llvm/MC/MCStreamer.h" +#include "llvm/MC/MCSymbol.h" +#include "llvm/Target/TargetData.h" +#include "llvm/Target/TargetFrameInfo.h" +#include "llvm/Target/TargetLoweringObjectFile.h" +#include "llvm/Target/TargetMachine.h" +#include "llvm/Target/TargetRegisterInfo.h" +#include "llvm/ADT/Twine.h" +#include "llvm/Support/Dwarf.h" +using namespace llvm; + +//===----------------------------------------------------------------------===// +// Dwarf Emission Helper Routines +//===----------------------------------------------------------------------===// + +/// EmitSLEB128 - emit the specified signed leb128 value. +void AsmPrinter::EmitSLEB128(int Value, const char *Desc) const { + if (isVerbose() && Desc) + OutStreamer.AddComment(Desc); + + if (MAI->hasLEB128()) { + // FIXME: MCize. + OutStreamer.EmitRawText("\t.sleb128\t" + Twine(Value)); + return; + } + + // If we don't have .sleb128, emit as .bytes. + int Sign = Value >> (8 * sizeof(Value) - 1); + bool IsMore; + + do { + unsigned char Byte = static_cast<unsigned char>(Value & 0x7f); + Value >>= 7; + IsMore = Value != Sign || ((Byte ^ Sign) & 0x40) != 0; + if (IsMore) Byte |= 0x80; + OutStreamer.EmitIntValue(Byte, 1, /*addrspace*/0); + } while (IsMore); +} + +/// EmitULEB128 - emit the specified signed leb128 value. +void AsmPrinter::EmitULEB128(unsigned Value, const char *Desc, + unsigned PadTo) const { + if (isVerbose() && Desc) + OutStreamer.AddComment(Desc); + + if (MAI->hasLEB128() && PadTo == 0) { + // FIXME: MCize. + OutStreamer.EmitRawText("\t.uleb128\t" + Twine(Value)); + return; + } + + // If we don't have .uleb128 or we want to emit padding, emit as .bytes. + do { + unsigned char Byte = static_cast<unsigned char>(Value & 0x7f); + Value >>= 7; + if (Value || PadTo != 0) Byte |= 0x80; + OutStreamer.EmitIntValue(Byte, 1, /*addrspace*/0); + } while (Value); + + if (PadTo) { + if (PadTo > 1) + OutStreamer.EmitFill(PadTo - 1, 0x80/*fillval*/, 0/*addrspace*/); + OutStreamer.EmitFill(1, 0/*fillval*/, 0/*addrspace*/); + } +} + +/// EmitCFAByte - Emit a .byte 42 directive for a DW_CFA_xxx value. +void AsmPrinter::EmitCFAByte(unsigned Val) const { + if (isVerbose()) { + if (Val >= dwarf::DW_CFA_offset && Val < dwarf::DW_CFA_offset+64) + OutStreamer.AddComment("DW_CFA_offset + Reg (" + + Twine(Val-dwarf::DW_CFA_offset) + ")"); + else + OutStreamer.AddComment(dwarf::CallFrameString(Val)); + } + OutStreamer.EmitIntValue(Val, 1, 0/*addrspace*/); +} + +static const char *DecodeDWARFEncoding(unsigned Encoding) { + switch (Encoding) { + case dwarf::DW_EH_PE_absptr: return "absptr"; + case dwarf::DW_EH_PE_omit: return "omit"; + case dwarf::DW_EH_PE_pcrel: return "pcrel"; + case dwarf::DW_EH_PE_udata4: return "udata4"; + case dwarf::DW_EH_PE_udata8: return "udata8"; + case dwarf::DW_EH_PE_sdata4: return "sdata4"; + case dwarf::DW_EH_PE_sdata8: return "sdata8"; + case dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_udata4: return "pcrel udata4"; + case dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4: return "pcrel sdata4"; + case dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_udata8: return "pcrel udata8"; + case dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata8: return "pcrel sdata8"; + case dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |dwarf::DW_EH_PE_udata4: + return "indirect pcrel udata4"; + case dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |dwarf::DW_EH_PE_sdata4: + return "indirect pcrel sdata4"; + case dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |dwarf::DW_EH_PE_udata8: + return "indirect pcrel udata8"; + case dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |dwarf::DW_EH_PE_sdata8: + return "indirect pcrel sdata8"; + } + + return "<unknown encoding>"; +} + + +/// EmitEncodingByte - Emit a .byte 42 directive that corresponds to an +/// encoding. If verbose assembly output is enabled, we output comments +/// describing the encoding. Desc is an optional string saying what the +/// encoding is specifying (e.g. "LSDA"). +void AsmPrinter::EmitEncodingByte(unsigned Val, const char *Desc) const { + if (isVerbose()) { + if (Desc != 0) + OutStreamer.AddComment(Twine(Desc)+" Encoding = " + + Twine(DecodeDWARFEncoding(Val))); + else + OutStreamer.AddComment(Twine("Encoding = ") + + DecodeDWARFEncoding(Val)); + } + + OutStreamer.EmitIntValue(Val, 1, 0/*addrspace*/); +} + +/// GetSizeOfEncodedValue - Return the size of the encoding in bytes. +unsigned AsmPrinter::GetSizeOfEncodedValue(unsigned Encoding) const { + if (Encoding == dwarf::DW_EH_PE_omit) + return 0; + + switch (Encoding & 0x07) { + default: assert(0 && "Invalid encoded value."); + case dwarf::DW_EH_PE_absptr: return TM.getTargetData()->getPointerSize(); + case dwarf::DW_EH_PE_udata2: return 2; + case dwarf::DW_EH_PE_udata4: return 4; + case dwarf::DW_EH_PE_udata8: return 8; + } +} + +void AsmPrinter::EmitReference(const MCSymbol *Sym, unsigned Encoding) const { + const TargetLoweringObjectFile &TLOF = getObjFileLowering(); + + const MCExpr *Exp = + TLOF.getExprForDwarfReference(Sym, Mang, MMI, Encoding, OutStreamer); + OutStreamer.EmitValue(Exp, GetSizeOfEncodedValue(Encoding), /*addrspace*/0); +} + +void AsmPrinter::EmitReference(const GlobalValue *GV, unsigned Encoding)const{ + const TargetLoweringObjectFile &TLOF = getObjFileLowering(); + + const MCExpr *Exp = + TLOF.getExprForDwarfGlobalReference(GV, Mang, MMI, Encoding, OutStreamer); + OutStreamer.EmitValue(Exp, GetSizeOfEncodedValue(Encoding), /*addrspace*/0); +} + +/// EmitSectionOffset - Emit the 4-byte offset of Label from the start of its +/// section. This can be done with a special directive if the target supports +/// it (e.g. cygwin) or by emitting it as an offset from a label at the start +/// of the section. +/// +/// SectionLabel is a temporary label emitted at the start of the section that +/// Label lives in. +void AsmPrinter::EmitSectionOffset(const MCSymbol *Label, + const MCSymbol *SectionLabel) const { + // On COFF targets, we have to emit the special .secrel32 directive. + if (const char *SecOffDir = MAI->getDwarfSectionOffsetDirective()) { + // FIXME: MCize. + OutStreamer.EmitRawText(SecOffDir + Twine(Label->getName())); + return; + } + + // Get the section that we're referring to, based on SectionLabel. + const MCSection &Section = SectionLabel->getSection(); + + // If Label has already been emitted, verify that it is in the same section as + // section label for sanity. + assert((!Label->isInSection() || &Label->getSection() == &Section) && + "Section offset using wrong section base for label"); + + // If the section in question will end up with an address of 0 anyway, we can + // just emit an absolute reference to save a relocation. + if (Section.isBaseAddressKnownZero()) { + OutStreamer.EmitSymbolValue(Label, 4, 0/*AddrSpace*/); + return; + } + + // Otherwise, emit it as a label difference from the start of the section. + EmitLabelDifference(Label, SectionLabel, 4); +} + +//===----------------------------------------------------------------------===// +// Dwarf Lowering Routines +//===----------------------------------------------------------------------===// + + +/// EmitFrameMoves - Emit frame instructions to describe the layout of the +/// frame. +void AsmPrinter::EmitFrameMoves(const std::vector<MachineMove> &Moves, + MCSymbol *BaseLabel, bool isEH) const { + const TargetRegisterInfo *RI = TM.getRegisterInfo(); + + int stackGrowth = TM.getTargetData()->getPointerSize(); + if (TM.getFrameInfo()->getStackGrowthDirection() != + TargetFrameInfo::StackGrowsUp) + stackGrowth *= -1; + + for (unsigned i = 0, N = Moves.size(); i < N; ++i) { + const MachineMove &Move = Moves[i]; + MCSymbol *Label = Move.getLabel(); + // Throw out move if the label is invalid. + if (Label && !Label->isDefined()) continue; // Not emitted, in dead code. + + const MachineLocation &Dst = Move.getDestination(); + const MachineLocation &Src = Move.getSource(); + + // Advance row if new location. + if (BaseLabel && Label) { + MCSymbol *ThisSym = Label; + if (ThisSym != BaseLabel) { + EmitCFAByte(dwarf::DW_CFA_advance_loc4); + EmitLabelDifference(ThisSym, BaseLabel, 4); + BaseLabel = ThisSym; + } + } + + // If advancing cfa. + if (Dst.isReg() && Dst.getReg() == MachineLocation::VirtualFP) { + assert(!Src.isReg() && "Machine move not supported yet."); + + if (Src.getReg() == MachineLocation::VirtualFP) { + EmitCFAByte(dwarf::DW_CFA_def_cfa_offset); + } else { + EmitCFAByte(dwarf::DW_CFA_def_cfa); + EmitULEB128(RI->getDwarfRegNum(Src.getReg(), isEH), "Register"); + } + + EmitULEB128(-Src.getOffset(), "Offset"); + continue; + } + + if (Src.isReg() && Src.getReg() == MachineLocation::VirtualFP) { + assert(Dst.isReg() && "Machine move not supported yet."); + EmitCFAByte(dwarf::DW_CFA_def_cfa_register); + EmitULEB128(RI->getDwarfRegNum(Dst.getReg(), isEH), "Register"); + continue; + } + + unsigned Reg = RI->getDwarfRegNum(Src.getReg(), isEH); + int Offset = Dst.getOffset() / stackGrowth; + + if (Offset < 0) { + EmitCFAByte(dwarf::DW_CFA_offset_extended_sf); + EmitULEB128(Reg, "Reg"); + EmitSLEB128(Offset, "Offset"); + } else if (Reg < 64) { + EmitCFAByte(dwarf::DW_CFA_offset + Reg); + EmitULEB128(Offset, "Offset"); + } else { + EmitCFAByte(dwarf::DW_CFA_offset_extended); + EmitULEB128(Reg, "Reg"); + EmitULEB128(Offset, "Offset"); + } + } +} |
