diff options
Diffstat (limited to 'lib/CodeGen/AsmPrinter/AsmPrinterDwarf.cpp')
| -rw-r--r-- | lib/CodeGen/AsmPrinter/AsmPrinterDwarf.cpp | 253 |
1 files changed, 224 insertions, 29 deletions
diff --git a/lib/CodeGen/AsmPrinter/AsmPrinterDwarf.cpp b/lib/CodeGen/AsmPrinter/AsmPrinterDwarf.cpp index b92f49cfaed8..02cd12be0453 100644 --- a/lib/CodeGen/AsmPrinter/AsmPrinterDwarf.cpp +++ b/lib/CodeGen/AsmPrinter/AsmPrinterDwarf.cpp @@ -11,8 +11,9 @@ // //===----------------------------------------------------------------------===// -#define DEBUG_TYPE "asm-printer" +#include "ByteStreamer.h" #include "llvm/CodeGen/AsmPrinter.h" +#include "llvm/ADT/SmallBitVector.h" #include "llvm/ADT/Twine.h" #include "llvm/IR/DataLayout.h" #include "llvm/MC/MCAsmInfo.h" @@ -28,6 +29,8 @@ #include "llvm/Target/TargetRegisterInfo.h" using namespace llvm; +#define DEBUG_TYPE "asm-printer" + //===----------------------------------------------------------------------===// // Dwarf Emission Helper Routines //===----------------------------------------------------------------------===// @@ -52,9 +55,9 @@ void AsmPrinter::EmitULEB128(uint64_t Value, const char *Desc, /// 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) + if (Val >= dwarf::DW_CFA_offset && Val < dwarf::DW_CFA_offset + 64) OutStreamer.AddComment("DW_CFA_offset + Reg (" + - Twine(Val-dwarf::DW_CFA_offset) + ")"); + Twine(Val - dwarf::DW_CFA_offset) + ")"); else OutStreamer.AddComment(dwarf::CallFrameString(Val)); } @@ -63,43 +66,56 @@ void AsmPrinter::EmitCFAByte(unsigned Val) const { 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: + 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: + 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: + 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: + 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 = " + + if (Desc) + OutStreamer.AddComment(Twine(Desc) + " Encoding = " + Twine(DecodeDWARFEncoding(Val))); else - OutStreamer.AddComment(Twine("Encoding = ") + - DecodeDWARFEncoding(Val)); + OutStreamer.AddComment(Twine("Encoding = ") + DecodeDWARFEncoding(Val)); } OutStreamer.EmitIntValue(Val, 1); @@ -111,11 +127,16 @@ unsigned AsmPrinter::GetSizeOfEncodedValue(unsigned Encoding) const { return 0; switch (Encoding & 0x07) { - default: llvm_unreachable("Invalid encoded value."); - case dwarf::DW_EH_PE_absptr: return TM.getDataLayout()->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; + default: + llvm_unreachable("Invalid encoded value."); + case dwarf::DW_EH_PE_absptr: + return TM.getDataLayout()->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; } } @@ -125,7 +146,7 @@ void AsmPrinter::EmitTTypeReference(const GlobalValue *GV, const TargetLoweringObjectFile &TLOF = getObjFileLowering(); const MCExpr *Exp = - TLOF.getTTypeGlobalReference(GV, Mang, MMI, Encoding, OutStreamer); + TLOF.getTTypeGlobalReference(GV, Encoding, *Mang, TM, MMI, OutStreamer); OutStreamer.EmitValue(Exp, GetSizeOfEncodedValue(Encoding)); } else OutStreamer.EmitIntValue(0, GetSizeOfEncodedValue(Encoding)); @@ -165,6 +186,177 @@ void AsmPrinter::EmitSectionOffset(const MCSymbol *Label, EmitLabelDifference(Label, SectionLabel, 4); } +/// Emit a dwarf register operation. +static void emitDwarfRegOp(ByteStreamer &Streamer, int Reg) { + assert(Reg >= 0); + if (Reg < 32) { + Streamer.EmitInt8(dwarf::DW_OP_reg0 + Reg, + dwarf::OperationEncodingString(dwarf::DW_OP_reg0 + Reg)); + } else { + Streamer.EmitInt8(dwarf::DW_OP_regx, "DW_OP_regx"); + Streamer.EmitULEB128(Reg, Twine(Reg)); + } +} + +/// Emit an (double-)indirect dwarf register operation. +static void emitDwarfRegOpIndirect(ByteStreamer &Streamer, int Reg, int Offset, + bool Deref) { + assert(Reg >= 0); + if (Reg < 32) { + Streamer.EmitInt8(dwarf::DW_OP_breg0 + Reg, + dwarf::OperationEncodingString(dwarf::DW_OP_breg0 + Reg)); + } else { + Streamer.EmitInt8(dwarf::DW_OP_bregx, "DW_OP_bregx"); + Streamer.EmitULEB128(Reg, Twine(Reg)); + } + Streamer.EmitSLEB128(Offset); + if (Deref) + Streamer.EmitInt8(dwarf::DW_OP_deref, "DW_OP_deref"); +} + +/// Emit a dwarf register operation for describing +/// - a small value occupying only part of a register or +/// - a small register representing only part of a value. +static void emitDwarfOpPiece(ByteStreamer &Streamer, unsigned SizeInBits, + unsigned OffsetInBits) { + assert(SizeInBits > 0 && "zero-sized piece"); + unsigned SizeOfByte = 8; + if (OffsetInBits > 0 || SizeInBits % SizeOfByte) { + Streamer.EmitInt8(dwarf::DW_OP_bit_piece, "DW_OP_bit_piece"); + Streamer.EmitULEB128(SizeInBits, Twine(SizeInBits)); + Streamer.EmitULEB128(OffsetInBits, Twine(OffsetInBits)); + } else { + Streamer.EmitInt8(dwarf::DW_OP_piece, "DW_OP_piece"); + unsigned ByteSize = SizeInBits / SizeOfByte; + Streamer.EmitULEB128(ByteSize, Twine(ByteSize)); + } +} + +/// Emit a shift-right dwarf expression. +static void emitDwarfOpShr(ByteStreamer &Streamer, + unsigned ShiftBy) { + Streamer.EmitInt8(dwarf::DW_OP_constu, "DW_OP_constu"); + Streamer.EmitULEB128(ShiftBy); + Streamer.EmitInt8(dwarf::DW_OP_shr, "DW_OP_shr"); +} + +// Some targets do not provide a DWARF register number for every +// register. This function attempts to emit a DWARF register by +// emitting a piece of a super-register or by piecing together +// multiple subregisters that alias the register. +void AsmPrinter::EmitDwarfRegOpPiece(ByteStreamer &Streamer, + const MachineLocation &MLoc, + unsigned PieceSizeInBits, + unsigned PieceOffsetInBits) const { + assert(MLoc.isReg() && "MLoc must be a register"); + const TargetRegisterInfo *TRI = TM.getRegisterInfo(); + int Reg = TRI->getDwarfRegNum(MLoc.getReg(), false); + + // If this is a valid register number, emit it. + if (Reg >= 0) { + emitDwarfRegOp(Streamer, Reg); + emitDwarfOpPiece(Streamer, PieceSizeInBits, PieceOffsetInBits); + return; + } + + // Walk up the super-register chain until we find a valid number. + // For example, EAX on x86_64 is a 32-bit piece of RAX with offset 0. + for (MCSuperRegIterator SR(MLoc.getReg(), TRI); SR.isValid(); ++SR) { + Reg = TRI->getDwarfRegNum(*SR, false); + if (Reg >= 0) { + unsigned Idx = TRI->getSubRegIndex(*SR, MLoc.getReg()); + unsigned Size = TRI->getSubRegIdxSize(Idx); + unsigned Offset = TRI->getSubRegIdxOffset(Idx); + OutStreamer.AddComment("super-register"); + emitDwarfRegOp(Streamer, Reg); + if (PieceOffsetInBits == Offset) { + emitDwarfOpPiece(Streamer, Size, Offset); + } else { + // If this is part of a variable in a sub-register at a + // non-zero offset, we need to manually shift the value into + // place, since the DW_OP_piece describes the part of the + // variable, not the position of the subregister. + emitDwarfOpPiece(Streamer, Size, PieceOffsetInBits); + if (Offset) + emitDwarfOpShr(Streamer, Offset); + } + return; + } + } + + // Otherwise, attempt to find a covering set of sub-register numbers. + // For example, Q0 on ARM is a composition of D0+D1. + // + // Keep track of the current position so we can emit the more + // efficient DW_OP_piece. + unsigned CurPos = PieceOffsetInBits; + // The size of the register in bits, assuming 8 bits per byte. + unsigned RegSize = TRI->getMinimalPhysRegClass(MLoc.getReg())->getSize() * 8; + // Keep track of the bits in the register we already emitted, so we + // can avoid emitting redundant aliasing subregs. + SmallBitVector Coverage(RegSize, false); + for (MCSubRegIterator SR(MLoc.getReg(), TRI); SR.isValid(); ++SR) { + unsigned Idx = TRI->getSubRegIndex(MLoc.getReg(), *SR); + unsigned Size = TRI->getSubRegIdxSize(Idx); + unsigned Offset = TRI->getSubRegIdxOffset(Idx); + Reg = TRI->getDwarfRegNum(*SR, false); + + // Intersection between the bits we already emitted and the bits + // covered by this subregister. + SmallBitVector Intersection(RegSize, false); + Intersection.set(Offset, Offset + Size); + Intersection ^= Coverage; + + // If this sub-register has a DWARF number and we haven't covered + // its range, emit a DWARF piece for it. + if (Reg >= 0 && Intersection.any()) { + OutStreamer.AddComment("sub-register"); + emitDwarfRegOp(Streamer, Reg); + emitDwarfOpPiece(Streamer, Size, Offset == CurPos ? 0 : Offset); + CurPos = Offset + Size; + + // Mark it as emitted. + Coverage.set(Offset, Offset + Size); + } + } + + if (CurPos == PieceOffsetInBits) { + // FIXME: We have no reasonable way of handling errors in here. + Streamer.EmitInt8(dwarf::DW_OP_nop, + "nop (could not find a dwarf register number)"); + } +} + +/// EmitDwarfRegOp - Emit dwarf register operation. +void AsmPrinter::EmitDwarfRegOp(ByteStreamer &Streamer, + const MachineLocation &MLoc, + bool Indirect) const { + const TargetRegisterInfo *TRI = TM.getRegisterInfo(); + int Reg = TRI->getDwarfRegNum(MLoc.getReg(), false); + if (Reg < 0) { + // We assume that pointers are always in an addressable register. + if (Indirect || MLoc.isIndirect()) { + // FIXME: We have no reasonable way of handling errors in here. The + // caller might be in the middle of a dwarf expression. We should + // probably assert that Reg >= 0 once debug info generation is more + // mature. + Streamer.EmitInt8(dwarf::DW_OP_nop, + "nop (invalid dwarf register number for indirect loc)"); + return; + } + + // Attempt to find a valid super- or sub-register. + return EmitDwarfRegOpPiece(Streamer, MLoc); + } + + if (MLoc.isIndirect()) + emitDwarfRegOpIndirect(Streamer, Reg, MLoc.getOffset(), Indirect); + else if (Indirect) + emitDwarfRegOpIndirect(Streamer, Reg, 0, false); + else + emitDwarfRegOp(Streamer, Reg); +} + //===----------------------------------------------------------------------===// // Dwarf Lowering Routines //===----------------------------------------------------------------------===// @@ -191,5 +383,8 @@ void AsmPrinter::emitCFIInstruction(const MCCFIInstruction &Inst) const { case MCCFIInstruction::OpWindowSave: OutStreamer.EmitCFIWindowSave(); break; + case MCCFIInstruction::OpSameValue: + OutStreamer.EmitCFISameValue(Inst.getRegister()); + break; } } |