//===- lib/MC/MCAsmStreamer.cpp - Text Assembly Output --------------------===// // // The LLVM Compiler Infrastructure // // This file is distributed under the University of Illinois Open Source // License. See LICENSE.TXT for details. // //===----------------------------------------------------------------------===// #include "llvm/MC/MCStreamer.h" #include "llvm/MC/MCAsmInfo.h" #include "llvm/MC/MCCodeEmitter.h" #include "llvm/MC/MCContext.h" #include "llvm/MC/MCExpr.h" #include "llvm/MC/MCInst.h" #include "llvm/MC/MCInstPrinter.h" #include "llvm/MC/MCSectionMachO.h" #include "llvm/MC/MCSymbol.h" #include "llvm/ADT/OwningPtr.h" #include "llvm/ADT/SmallString.h" #include "llvm/ADT/Twine.h" #include "llvm/Support/ErrorHandling.h" #include "llvm/Support/MathExtras.h" #include "llvm/Support/Format.h" #include "llvm/Support/FormattedStream.h" using namespace llvm; namespace { class MCAsmStreamer : public MCStreamer { formatted_raw_ostream &OS; const MCAsmInfo &MAI; OwningPtr InstPrinter; OwningPtr Emitter; SmallString<128> CommentToEmit; raw_svector_ostream CommentStream; unsigned IsLittleEndian : 1; unsigned IsVerboseAsm : 1; unsigned ShowInst : 1; public: MCAsmStreamer(MCContext &Context, formatted_raw_ostream &os, bool isLittleEndian, bool isVerboseAsm, MCInstPrinter *printer, MCCodeEmitter *emitter, bool showInst) : MCStreamer(Context), OS(os), MAI(Context.getAsmInfo()), InstPrinter(printer), Emitter(emitter), CommentStream(CommentToEmit), IsLittleEndian(isLittleEndian), IsVerboseAsm(isVerboseAsm), ShowInst(showInst) { if (InstPrinter && IsVerboseAsm) InstPrinter->setCommentStream(CommentStream); } ~MCAsmStreamer() {} bool isLittleEndian() const { return IsLittleEndian; } inline void EmitEOL() { // If we don't have any comments, just emit a \n. if (!IsVerboseAsm) { OS << '\n'; return; } EmitCommentsAndEOL(); } void EmitCommentsAndEOL(); /// isVerboseAsm - Return true if this streamer supports verbose assembly at /// all. virtual bool isVerboseAsm() const { return IsVerboseAsm; } /// hasRawTextSupport - We support EmitRawText. virtual bool hasRawTextSupport() const { return true; } /// AddComment - Add a comment that can be emitted to the generated .s /// file if applicable as a QoI issue to make the output of the compiler /// more readable. This only affects the MCAsmStreamer, and only when /// verbose assembly output is enabled. virtual void AddComment(const Twine &T); /// AddEncodingComment - Add a comment showing the encoding of an instruction. virtual void AddEncodingComment(const MCInst &Inst); /// GetCommentOS - Return a raw_ostream that comments can be written to. /// Unlike AddComment, you are required to terminate comments with \n if you /// use this method. virtual raw_ostream &GetCommentOS() { if (!IsVerboseAsm) return nulls(); // Discard comments unless in verbose asm mode. return CommentStream; } /// AddBlankLine - Emit a blank line to a .s file to pretty it up. virtual void AddBlankLine() { EmitEOL(); } /// @name MCStreamer Interface /// @{ virtual void SwitchSection(const MCSection *Section); virtual void EmitLabel(MCSymbol *Symbol); virtual void EmitAssemblerFlag(MCAssemblerFlag Flag); virtual void EmitAssignment(MCSymbol *Symbol, const MCExpr *Value); virtual void EmitSymbolAttribute(MCSymbol *Symbol, MCSymbolAttr Attribute); virtual void EmitSymbolDesc(MCSymbol *Symbol, unsigned DescValue); virtual void BeginCOFFSymbolDef(const MCSymbol *Symbol); virtual void EmitCOFFSymbolStorageClass(int StorageClass); virtual void EmitCOFFSymbolType(int Type); virtual void EndCOFFSymbolDef(); virtual void EmitELFSize(MCSymbol *Symbol, const MCExpr *Value); virtual void EmitCommonSymbol(MCSymbol *Symbol, uint64_t Size, unsigned ByteAlignment); /// EmitLocalCommonSymbol - Emit a local common (.lcomm) symbol. /// /// @param Symbol - The common symbol to emit. /// @param Size - The size of the common symbol. virtual void EmitLocalCommonSymbol(MCSymbol *Symbol, uint64_t Size); virtual void EmitZerofill(const MCSection *Section, MCSymbol *Symbol = 0, unsigned Size = 0, unsigned ByteAlignment = 0); virtual void EmitTBSSSymbol (const MCSection *Section, MCSymbol *Symbol, uint64_t Size, unsigned ByteAlignment = 0); virtual void EmitBytes(StringRef Data, unsigned AddrSpace); virtual void EmitValue(const MCExpr *Value, unsigned Size,unsigned AddrSpace); virtual void EmitIntValue(uint64_t Value, unsigned Size, unsigned AddrSpace); virtual void EmitGPRel32Value(const MCExpr *Value); virtual void EmitFill(uint64_t NumBytes, uint8_t FillValue, unsigned AddrSpace); virtual void EmitValueToAlignment(unsigned ByteAlignment, int64_t Value = 0, unsigned ValueSize = 1, unsigned MaxBytesToEmit = 0); virtual void EmitCodeAlignment(unsigned ByteAlignment, unsigned MaxBytesToEmit = 0); virtual void EmitValueToOffset(const MCExpr *Offset, unsigned char Value = 0); virtual void EmitFileDirective(StringRef Filename); virtual void EmitDwarfFileDirective(unsigned FileNo, StringRef Filename); virtual void EmitInstruction(const MCInst &Inst); /// EmitRawText - If this file is backed by a assembly streamer, this dumps /// the specified string in the output .s file. This capability is /// indicated by the hasRawTextSupport() predicate. virtual void EmitRawText(StringRef String); virtual void Finish(); /// @} }; } // end anonymous namespace. /// AddComment - Add a comment that can be emitted to the generated .s /// file if applicable as a QoI issue to make the output of the compiler /// more readable. This only affects the MCAsmStreamer, and only when /// verbose assembly output is enabled. void MCAsmStreamer::AddComment(const Twine &T) { if (!IsVerboseAsm) return; // Make sure that CommentStream is flushed. CommentStream.flush(); T.toVector(CommentToEmit); // Each comment goes on its own line. CommentToEmit.push_back('\n'); // Tell the comment stream that the vector changed underneath it. CommentStream.resync(); } void MCAsmStreamer::EmitCommentsAndEOL() { if (CommentToEmit.empty() && CommentStream.GetNumBytesInBuffer() == 0) { OS << '\n'; return; } CommentStream.flush(); StringRef Comments = CommentToEmit.str(); assert(Comments.back() == '\n' && "Comment array not newline terminated"); do { // Emit a line of comments. OS.PadToColumn(MAI.getCommentColumn()); size_t Position = Comments.find('\n'); OS << MAI.getCommentString() << ' ' << Comments.substr(0, Position) << '\n'; Comments = Comments.substr(Position+1); } while (!Comments.empty()); CommentToEmit.clear(); // Tell the comment stream that the vector changed underneath it. CommentStream.resync(); } static inline int64_t truncateToSize(int64_t Value, unsigned Bytes) { assert(Bytes && "Invalid size!"); return Value & ((uint64_t) (int64_t) -1 >> (64 - Bytes * 8)); } void MCAsmStreamer::SwitchSection(const MCSection *Section) { assert(Section && "Cannot switch to a null section!"); if (Section != CurSection) { PrevSection = CurSection; CurSection = Section; Section->PrintSwitchToSection(MAI, OS); } } void MCAsmStreamer::EmitLabel(MCSymbol *Symbol) { assert(Symbol->isUndefined() && "Cannot define a symbol twice!"); assert(!Symbol->isVariable() && "Cannot emit a variable symbol!"); assert(CurSection && "Cannot emit before setting section!"); OS << *Symbol << ":"; EmitEOL(); Symbol->setSection(*CurSection); } void MCAsmStreamer::EmitAssemblerFlag(MCAssemblerFlag Flag) { switch (Flag) { default: assert(0 && "Invalid flag!"); case MCAF_SubsectionsViaSymbols: OS << ".subsections_via_symbols"; break; } EmitEOL(); } void MCAsmStreamer::EmitAssignment(MCSymbol *Symbol, const MCExpr *Value) { OS << *Symbol << " = " << *Value; EmitEOL(); // FIXME: Lift context changes into super class. Symbol->setVariableValue(Value); } void MCAsmStreamer::EmitSymbolAttribute(MCSymbol *Symbol, MCSymbolAttr Attribute) { switch (Attribute) { case MCSA_Invalid: assert(0 && "Invalid symbol attribute"); case MCSA_ELF_TypeFunction: /// .type _foo, STT_FUNC # aka @function case MCSA_ELF_TypeIndFunction: /// .type _foo, STT_GNU_IFUNC case MCSA_ELF_TypeObject: /// .type _foo, STT_OBJECT # aka @object case MCSA_ELF_TypeTLS: /// .type _foo, STT_TLS # aka @tls_object case MCSA_ELF_TypeCommon: /// .type _foo, STT_COMMON # aka @common case MCSA_ELF_TypeNoType: /// .type _foo, STT_NOTYPE # aka @notype assert(MAI.hasDotTypeDotSizeDirective() && "Symbol Attr not supported"); OS << "\t.type\t" << *Symbol << ',' << ((MAI.getCommentString()[0] != '@') ? '@' : '%'); switch (Attribute) { default: assert(0 && "Unknown ELF .type"); case MCSA_ELF_TypeFunction: OS << "function"; break; case MCSA_ELF_TypeIndFunction: OS << "gnu_indirect_function"; break; case MCSA_ELF_TypeObject: OS << "object"; break; case MCSA_ELF_TypeTLS: OS << "tls_object"; break; case MCSA_ELF_TypeCommon: OS << "common"; break; case MCSA_ELF_TypeNoType: OS << "no_type"; break; } EmitEOL(); return; case MCSA_Global: // .globl/.global OS << MAI.getGlobalDirective(); break; case MCSA_Hidden: OS << "\t.hidden\t"; break; case MCSA_IndirectSymbol: OS << "\t.indirect_symbol\t"; break; case MCSA_Internal: OS << "\t.internal\t"; break; case MCSA_LazyReference: OS << "\t.lazy_reference\t"; break; case MCSA_Local: OS << "\t.local\t"; break; case MCSA_NoDeadStrip: OS << "\t.no_dead_strip\t"; break; case MCSA_PrivateExtern: OS << "\t.private_extern\t"; break; case MCSA_Protected: OS << "\t.protected\t"; break; case MCSA_Reference: OS << "\t.reference\t"; break; case MCSA_Weak: OS << "\t.weak\t"; break; case MCSA_WeakDefinition: OS << "\t.weak_definition\t"; break; // .weak_reference case MCSA_WeakReference: OS << MAI.getWeakRefDirective(); break; case MCSA_WeakDefAutoPrivate: OS << "\t.weak_def_can_be_hidden\t"; break; } OS << *Symbol; EmitEOL(); } void MCAsmStreamer::EmitSymbolDesc(MCSymbol *Symbol, unsigned DescValue) { OS << ".desc" << ' ' << *Symbol << ',' << DescValue; EmitEOL(); } void MCAsmStreamer::BeginCOFFSymbolDef(const MCSymbol *Symbol) { OS << "\t.def\t " << *Symbol << ';'; EmitEOL(); } void MCAsmStreamer::EmitCOFFSymbolStorageClass (int StorageClass) { OS << "\t.scl\t" << StorageClass << ';'; EmitEOL(); } void MCAsmStreamer::EmitCOFFSymbolType (int Type) { OS << "\t.type\t" << Type << ';'; EmitEOL(); } void MCAsmStreamer::EndCOFFSymbolDef() { OS << "\t.endef"; EmitEOL(); } void MCAsmStreamer::EmitELFSize(MCSymbol *Symbol, const MCExpr *Value) { assert(MAI.hasDotTypeDotSizeDirective()); OS << "\t.size\t" << *Symbol << ", " << *Value << '\n'; } void MCAsmStreamer::EmitCommonSymbol(MCSymbol *Symbol, uint64_t Size, unsigned ByteAlignment) { OS << "\t.comm\t" << *Symbol << ',' << Size; if (ByteAlignment != 0) { if (MAI.getCOMMDirectiveAlignmentIsInBytes()) OS << ',' << ByteAlignment; else OS << ',' << Log2_32(ByteAlignment); } EmitEOL(); } /// EmitLocalCommonSymbol - Emit a local common (.lcomm) symbol. /// /// @param Symbol - The common symbol to emit. /// @param Size - The size of the common symbol. void MCAsmStreamer::EmitLocalCommonSymbol(MCSymbol *Symbol, uint64_t Size) { assert(MAI.hasLCOMMDirective() && "Doesn't have .lcomm, can't emit it!"); OS << "\t.lcomm\t" << *Symbol << ',' << Size; EmitEOL(); } void MCAsmStreamer::EmitZerofill(const MCSection *Section, MCSymbol *Symbol, unsigned Size, unsigned ByteAlignment) { // Note: a .zerofill directive does not switch sections. OS << ".zerofill "; // This is a mach-o specific directive. const MCSectionMachO *MOSection = ((const MCSectionMachO*)Section); OS << MOSection->getSegmentName() << "," << MOSection->getSectionName(); if (Symbol != NULL) { OS << ',' << *Symbol << ',' << Size; if (ByteAlignment != 0) OS << ',' << Log2_32(ByteAlignment); } EmitEOL(); } // .tbss sym, size, align // This depends that the symbol has already been mangled from the original, // e.g. _a. void MCAsmStreamer::EmitTBSSSymbol(const MCSection *Section, MCSymbol *Symbol, uint64_t Size, unsigned ByteAlignment) { assert(Symbol != NULL && "Symbol shouldn't be NULL!"); // Instead of using the Section we'll just use the shortcut. // This is a mach-o specific directive and section. OS << ".tbss " << *Symbol << ", " << Size; // Output align if we have it. We default to 1 so don't bother printing // that. if (ByteAlignment > 1) OS << ", " << Log2_32(ByteAlignment); EmitEOL(); } static inline char toOctal(int X) { return (X&7)+'0'; } static void PrintQuotedString(StringRef Data, raw_ostream &OS) { OS << '"'; for (unsigned i = 0, e = Data.size(); i != e; ++i) { unsigned char C = Data[i]; if (C == '"' || C == '\\') { OS << '\\' << (char)C; continue; } if (isprint((unsigned char)C)) { OS << (char)C; continue; } switch (C) { case '\b': OS << "\\b"; break; case '\f': OS << "\\f"; break; case '\n': OS << "\\n"; break; case '\r': OS << "\\r"; break; case '\t': OS << "\\t"; break; default: OS << '\\'; OS << toOctal(C >> 6); OS << toOctal(C >> 3); OS << toOctal(C >> 0); break; } } OS << '"'; } void MCAsmStreamer::EmitBytes(StringRef Data, unsigned AddrSpace) { assert(CurSection && "Cannot emit contents before setting section!"); if (Data.empty()) return; if (Data.size() == 1) { OS << MAI.getData8bitsDirective(AddrSpace); OS << (unsigned)(unsigned char)Data[0]; EmitEOL(); return; } // If the data ends with 0 and the target supports .asciz, use it, otherwise // use .ascii if (MAI.getAscizDirective() && Data.back() == 0) { OS << MAI.getAscizDirective(); Data = Data.substr(0, Data.size()-1); } else { OS << MAI.getAsciiDirective(); } OS << ' '; PrintQuotedString(Data, OS); EmitEOL(); } /// EmitIntValue - Special case of EmitValue that avoids the client having /// to pass in a MCExpr for constant integers. void MCAsmStreamer::EmitIntValue(uint64_t Value, unsigned Size, unsigned AddrSpace) { assert(CurSection && "Cannot emit contents before setting section!"); const char *Directive = 0; switch (Size) { default: break; case 1: Directive = MAI.getData8bitsDirective(AddrSpace); break; case 2: Directive = MAI.getData16bitsDirective(AddrSpace); break; case 4: Directive = MAI.getData32bitsDirective(AddrSpace); break; case 8: Directive = MAI.getData64bitsDirective(AddrSpace); // If the target doesn't support 64-bit data, emit as two 32-bit halves. if (Directive) break; if (isLittleEndian()) { EmitIntValue((uint32_t)(Value >> 0 ), 4, AddrSpace); EmitIntValue((uint32_t)(Value >> 32), 4, AddrSpace); } else { EmitIntValue((uint32_t)(Value >> 32), 4, AddrSpace); EmitIntValue((uint32_t)(Value >> 0 ), 4, AddrSpace); } return; } assert(Directive && "Invalid size for machine code value!"); OS << Directive << truncateToSize(Value, Size); EmitEOL(); } void MCAsmStreamer::EmitValue(const MCExpr *Value, unsigned Size, unsigned AddrSpace) { assert(CurSection && "Cannot emit contents before setting section!"); const char *Directive = 0; switch (Size) { default: break; case 1: Directive = MAI.getData8bitsDirective(AddrSpace); break; case 2: Directive = MAI.getData16bitsDirective(AddrSpace); break; case 4: Directive = MAI.getData32bitsDirective(AddrSpace); break; case 8: Directive = MAI.getData64bitsDirective(AddrSpace); break; } assert(Directive && "Invalid size for machine code value!"); OS << Directive << *Value; EmitEOL(); } void MCAsmStreamer::EmitGPRel32Value(const MCExpr *Value) { assert(MAI.getGPRel32Directive() != 0); OS << MAI.getGPRel32Directive() << *Value; EmitEOL(); } /// EmitFill - Emit NumBytes bytes worth of the value specified by /// FillValue. This implements directives such as '.space'. void MCAsmStreamer::EmitFill(uint64_t NumBytes, uint8_t FillValue, unsigned AddrSpace) { if (NumBytes == 0) return; if (AddrSpace == 0) if (const char *ZeroDirective = MAI.getZeroDirective()) { OS << ZeroDirective << NumBytes; if (FillValue != 0) OS << ',' << (int)FillValue; EmitEOL(); return; } // Emit a byte at a time. MCStreamer::EmitFill(NumBytes, FillValue, AddrSpace); } void MCAsmStreamer::EmitValueToAlignment(unsigned ByteAlignment, int64_t Value, unsigned ValueSize, unsigned MaxBytesToEmit) { // Some assemblers don't support non-power of two alignments, so we always // emit alignments as a power of two if possible. if (isPowerOf2_32(ByteAlignment)) { switch (ValueSize) { default: llvm_unreachable("Invalid size for machine code value!"); case 1: OS << MAI.getAlignDirective(); break; // FIXME: use MAI for this! case 2: OS << ".p2alignw "; break; case 4: OS << ".p2alignl "; break; case 8: llvm_unreachable("Unsupported alignment size!"); } if (MAI.getAlignmentIsInBytes()) OS << ByteAlignment; else OS << Log2_32(ByteAlignment); if (Value || MaxBytesToEmit) { OS << ", 0x"; OS.write_hex(truncateToSize(Value, ValueSize)); if (MaxBytesToEmit) OS << ", " << MaxBytesToEmit; } EmitEOL(); return; } // Non-power of two alignment. This is not widely supported by assemblers. // FIXME: Parameterize this based on MAI. switch (ValueSize) { default: llvm_unreachable("Invalid size for machine code value!"); case 1: OS << ".balign"; break; case 2: OS << ".balignw"; break; case 4: OS << ".balignl"; break; case 8: llvm_unreachable("Unsupported alignment size!"); } OS << ' ' << ByteAlignment; OS << ", " << truncateToSize(Value, ValueSize); if (MaxBytesToEmit) OS << ", " << MaxBytesToEmit; EmitEOL(); } void MCAsmStreamer::EmitCodeAlignment(unsigned ByteAlignment, unsigned MaxBytesToEmit) { // Emit with a text fill value. EmitValueToAlignment(ByteAlignment, MAI.getTextAlignFillValue(), 1, MaxBytesToEmit); } void MCAsmStreamer::EmitValueToOffset(const MCExpr *Offset, unsigned char Value) { // FIXME: Verify that Offset is associated with the current section. OS << ".org " << *Offset << ", " << (unsigned) Value; EmitEOL(); } void MCAsmStreamer::EmitFileDirective(StringRef Filename) { assert(MAI.hasSingleParameterDotFile()); OS << "\t.file\t"; PrintQuotedString(Filename, OS); EmitEOL(); } void MCAsmStreamer::EmitDwarfFileDirective(unsigned FileNo, StringRef Filename){ OS << "\t.file\t" << FileNo << ' '; PrintQuotedString(Filename, OS); EmitEOL(); } void MCAsmStreamer::AddEncodingComment(const MCInst &Inst) { raw_ostream &OS = GetCommentOS(); SmallString<256> Code; SmallVector Fixups; raw_svector_ostream VecOS(Code); Emitter->EncodeInstruction(Inst, VecOS, Fixups); VecOS.flush(); // If we are showing fixups, create symbolic markers in the encoded // representation. We do this by making a per-bit map to the fixup item index, // then trying to display it as nicely as possible. SmallVector FixupMap; FixupMap.resize(Code.size() * 8); for (unsigned i = 0, e = Code.size() * 8; i != e; ++i) FixupMap[i] = 0; for (unsigned i = 0, e = Fixups.size(); i != e; ++i) { MCFixup &F = Fixups[i]; const MCFixupKindInfo &Info = Emitter->getFixupKindInfo(F.getKind()); for (unsigned j = 0; j != Info.TargetSize; ++j) { unsigned Index = F.getOffset() * 8 + Info.TargetOffset + j; assert(Index < Code.size() * 8 && "Invalid offset in fixup!"); FixupMap[Index] = 1 + i; } } OS << "encoding: ["; for (unsigned i = 0, e = Code.size(); i != e; ++i) { if (i) OS << ','; // See if all bits are the same map entry. uint8_t MapEntry = FixupMap[i * 8 + 0]; for (unsigned j = 1; j != 8; ++j) { if (FixupMap[i * 8 + j] == MapEntry) continue; MapEntry = uint8_t(~0U); break; } if (MapEntry != uint8_t(~0U)) { if (MapEntry == 0) { OS << format("0x%02x", uint8_t(Code[i])); } else { assert(Code[i] == 0 && "Encoder wrote into fixed up bit!"); OS << char('A' + MapEntry - 1); } } else { // Otherwise, write out in binary. OS << "0b"; for (unsigned j = 8; j--;) { unsigned Bit = (Code[i] >> j) & 1; if (uint8_t MapEntry = FixupMap[i * 8 + j]) { assert(Bit == 0 && "Encoder wrote into fixed up bit!"); OS << char('A' + MapEntry - 1); } else OS << Bit; } } } OS << "]\n"; for (unsigned i = 0, e = Fixups.size(); i != e; ++i) { MCFixup &F = Fixups[i]; const MCFixupKindInfo &Info = Emitter->getFixupKindInfo(F.getKind()); OS << " fixup " << char('A' + i) << " - " << "offset: " << F.getOffset() << ", value: " << *F.getValue() << ", kind: " << Info.Name << "\n"; } } void MCAsmStreamer::EmitInstruction(const MCInst &Inst) { assert(CurSection && "Cannot emit contents before setting section!"); // Show the encoding in a comment if we have a code emitter. if (Emitter) AddEncodingComment(Inst); // Show the MCInst if enabled. if (ShowInst) { Inst.dump_pretty(GetCommentOS(), &MAI, InstPrinter.get(), "\n "); GetCommentOS() << "\n"; } // If we have an AsmPrinter, use that to print, otherwise print the MCInst. if (InstPrinter) InstPrinter->printInst(&Inst, OS); else Inst.print(OS, &MAI); EmitEOL(); } /// EmitRawText - If this file is backed by a assembly streamer, this dumps /// the specified string in the output .s file. This capability is /// indicated by the hasRawTextSupport() predicate. void MCAsmStreamer::EmitRawText(StringRef String) { if (!String.empty() && String.back() == '\n') String = String.substr(0, String.size()-1); OS << String; EmitEOL(); } void MCAsmStreamer::Finish() { } MCStreamer *llvm::createAsmStreamer(MCContext &Context, formatted_raw_ostream &OS, bool isLittleEndian, bool isVerboseAsm, MCInstPrinter *IP, MCCodeEmitter *CE, bool ShowInst) { return new MCAsmStreamer(Context, OS, isLittleEndian, isVerboseAsm, IP, CE, ShowInst); }