text: //===-- llvm/MC/MCAsmInfo.h - Asm info --------------------------*- C++ -*-===//
  //
  //                     The LLVM Compiler Infrastructure
  //
  // This file is distributed under the University of Illinois Open Source
  // License. See LICENSE.TXT for details.
  //
  //===----------------------------------------------------------------------===//
  //
  // This file contains a class to be used as the basis for target specific
  // asm writers.  This class primarily takes care of global printing constants,
  // which are used in very similar ways across all targets.
  //
  //===----------------------------------------------------------------------===//
  
  #ifndef LLVM_MC_MCASMINFO_H
  #define LLVM_MC_MCASMINFO_H
  
  #include "llvm/MC/MCDirectives.h"
  #include "llvm/MC/MCDwarf.h"
  #include "llvm/MC/MachineLocation.h"
  #include <cassert>
  #include <vector>
  
  namespace llvm {
    class MCExpr;
    class MCSection;
    class MCStreamer;
    class MCSymbol;
    class MCContext;
  
    namespace ExceptionHandling {
      enum ExceptionsType { None, DwarfCFI, SjLj, ARM, Win64 };
    }
  
    namespace LCOMM {
      enum LCOMMType { NoAlignment, ByteAlignment, Log2Alignment };
    }
  
    /// MCAsmInfo - This class is intended to be used as a base class for asm
    /// properties and features specific to the target.
    class MCAsmInfo {
    protected:
      //===------------------------------------------------------------------===//
      // Properties to be set by the target writer, used to configure asm printer.
      //
  
      /// PointerSize - Pointer size in bytes.
      ///               Default is 4.
      unsigned PointerSize;
  
      /// CalleeSaveStackSlotSize - Size of the stack slot reserved for
      ///                           callee-saved registers, in bytes.
      ///                           Default is same as pointer size.
      unsigned CalleeSaveStackSlotSize;
  
      /// IsLittleEndian - True if target is little endian.
      ///                  Default is true.
      bool IsLittleEndian;
  
      /// StackGrowsUp - True if target stack grow up.
      ///                Default is false.
      bool StackGrowsUp;
  
      /// HasSubsectionsViaSymbols - True if this target has the MachO
      /// .subsections_via_symbols directive.
      bool HasSubsectionsViaSymbols;           // Default is false.
  
      /// HasMachoZeroFillDirective - True if this is a MachO target that supports
      /// the macho-specific .zerofill directive for emitting BSS Symbols.
      bool HasMachoZeroFillDirective;               // Default is false.
  
      /// HasMachoTBSSDirective - True if this is a MachO target that supports
      /// the macho-specific .tbss directive for emitting thread local BSS Symbols
      bool HasMachoTBSSDirective;                 // Default is false.
  
      /// HasStaticCtorDtorReferenceInStaticMode - True if the compiler should
      /// emit a ".reference .constructors_used" or ".reference .destructors_used"
      /// directive after the a static ctor/dtor list.  This directive is only
      /// emitted in Static relocation model.
      bool HasStaticCtorDtorReferenceInStaticMode;  // Default is false.
  
      /// LinkerRequiresNonEmptyDwarfLines - True if the linker has a bug and
      /// requires that the debug_line section be of a minimum size. In practice
      /// such a linker requires a non empty line sequence if a file is present.
      bool LinkerRequiresNonEmptyDwarfLines; // Default to false.
  
      /// MaxInstLength - This is the maximum possible length of an instruction,
      /// which is needed to compute the size of an inline asm.
      unsigned MaxInstLength;                  // Defaults to 4.
  
      /// MinInstAlignment - Every possible instruction length is a multiple of
      /// this value.  Factored out in .debug_frame and .debug_line.
      unsigned MinInstAlignment;                  // Defaults to 1.
  
      /// PCSymbol - The symbol used to represent the current PC.  Used in PC
      /// relative expressions.
      const char *PCSymbol;                    // Defaults to "$".
  
      /// SeparatorString - This string, if specified, is used to separate
      /// instructions from each other when on the same line.
      const char *SeparatorString;             // Defaults to ';'
  
      /// CommentColumn - This indicates the comment num (zero-based) at
      /// which asm comments should be printed.
      unsigned CommentColumn;                  // Defaults to 40
  
      /// CommentString - This indicates the comment character used by the
      /// assembler.
      const char *CommentString;               // Defaults to "#"
  
      /// LabelSuffix - This is appended to emitted labels.
      const char *LabelSuffix;                 // Defaults to ":"
  
      /// LabelSuffix - This is appended to emitted labels.
      const char *DebugLabelSuffix;                 // Defaults to ":"
  
      /// GlobalPrefix - If this is set to a non-empty string, it is prepended
      /// onto all global symbols.  This is often used for "_" or ".".
      const char *GlobalPrefix;                // Defaults to ""
  
      /// PrivateGlobalPrefix - This prefix is used for globals like constant
      /// pool entries that are completely private to the .s file and should not
      /// have names in the .o file.  This is often "." or "L".
      const char *PrivateGlobalPrefix;         // Defaults to "."
  
      /// LinkerPrivateGlobalPrefix - This prefix is used for symbols that should
      /// be passed through the assembler but be removed by the linker.  This
      /// is "l" on Darwin, currently used for some ObjC metadata.
      const char *LinkerPrivateGlobalPrefix;   // Defaults to ""
  
      /// InlineAsmStart/End - If these are nonempty, they contain a directive to
      /// emit before and after an inline assembly statement.
      const char *InlineAsmStart;              // Defaults to "#APP\n"
      const char *InlineAsmEnd;                // Defaults to "#NO_APP\n"
  
      /// Code16Directive, Code32Directive, Code64Directive - These are assembly
      /// directives that tells the assembler to interpret the following
      /// instructions differently.
      const char *Code16Directive;             // Defaults to ".code16"
      const char *Code32Directive;             // Defaults to ".code32"
      const char *Code64Directive;             // Defaults to ".code64"
  
      /// AssemblerDialect - Which dialect of an assembler variant to use.
      unsigned AssemblerDialect;               // Defaults to 0
  
      /// AllowQuotesInName - This is true if the assembler allows for complex
      /// symbol names to be surrounded in quotes.  This defaults to false.
      bool AllowQuotesInName;
  
      /// AllowNameToStartWithDigit - This is true if the assembler allows symbol
      /// names to start with a digit (e.g., "0x0021").  This defaults to false.
      bool AllowNameToStartWithDigit;
  
      /// AllowPeriodsInName - This is true if the assembler allows periods in
      /// symbol names.  This defaults to true.
      bool AllowPeriodsInName;
  
      /// AllowUTF8 - This is true if the assembler accepts UTF-8 input.
      // FIXME: Make this a more general encoding setting?
      bool AllowUTF8;
  
      /// UseDataRegionDirectives - This is true if data region markers should
      /// be printed as ".data_region/.end_data_region" directives. If false,
      /// use "$d/$a" labels instead.
      bool UseDataRegionDirectives;
  
      //===--- Data Emission Directives -------------------------------------===//
  
      /// ZeroDirective - this should be set to the directive used to get some
      /// number of zero bytes emitted to the current section.  Common cases are
      /// "\t.zero\t" and "\t.space\t".  If this is set to null, the
      /// Data*bitsDirective's will be used to emit zero bytes.
      const char *ZeroDirective;               // Defaults to "\t.zero\t"
  
      /// AsciiDirective - This directive allows emission of an ascii string with
      /// the standard C escape characters embedded into it.
      const char *AsciiDirective;              // Defaults to "\t.ascii\t"
  
      /// AscizDirective - If not null, this allows for special handling of
      /// zero terminated strings on this target.  This is commonly supported as
      /// ".asciz".  If a target doesn't support this, it can be set to null.
      const char *AscizDirective;              // Defaults to "\t.asciz\t"
  
      /// DataDirectives - These directives are used to output some unit of
      /// integer data to the current section.  If a data directive is set to
      /// null, smaller data directives will be used to emit the large sizes.
      const char *Data8bitsDirective;          // Defaults to "\t.byte\t"
      const char *Data16bitsDirective;         // Defaults to "\t.short\t"
      const char *Data32bitsDirective;         // Defaults to "\t.long\t"
      const char *Data64bitsDirective;         // Defaults to "\t.quad\t"
  
      /// GPRel64Directive - if non-null, a directive that is used to emit a word
      /// which should be relocated as a 64-bit GP-relative offset, e.g. .gpdword
      /// on Mips.
      const char *GPRel64Directive;            // Defaults to NULL.
  
      /// GPRel32Directive - if non-null, a directive that is used to emit a word
      /// which should be relocated as a 32-bit GP-relative offset, e.g. .gpword
      /// on Mips or .gprel32 on Alpha.
      const char *GPRel32Directive;            // Defaults to NULL.
  
      /// getDataASDirective - Return the directive that should be used to emit
      /// data of the specified size to the specified numeric address space.
      virtual const char *getDataASDirective(unsigned Size, unsigned AS) const {
        assert(AS != 0 && "Don't know the directives for default addr space");
        return 0;
      }
  
      /// SunStyleELFSectionSwitchSyntax - This is true if this target uses "Sun
      /// Style" syntax for section switching ("#alloc,#write" etc) instead of the
      /// normal ELF syntax (,"a,w") in .section directives.
      bool SunStyleELFSectionSwitchSyntax;     // Defaults to false.
  
      /// UsesELFSectionDirectiveForBSS - This is true if this target uses ELF
      /// '.section' directive before the '.bss' one. It's used for PPC/Linux
      /// which doesn't support the '.bss' directive only.
      bool UsesELFSectionDirectiveForBSS;      // Defaults to false.
  
      /// HasMicrosoftFastStdCallMangling - True if this target uses microsoft
      /// style mangling for functions with X86_StdCall/X86_FastCall calling
      /// convention.
      bool HasMicrosoftFastStdCallMangling;    // Defaults to false.
  
      bool NeedsDwarfSectionOffsetDirective;
  
      //===--- Alignment Information ----------------------------------------===//
  
      /// AlignDirective - The directive used to emit round up to an alignment
      /// boundary.
      ///
      const char *AlignDirective;              // Defaults to "\t.align\t"
  
      /// AlignmentIsInBytes - If this is true (the default) then the asmprinter
      /// emits ".align N" directives, where N is the number of bytes to align to.
      /// Otherwise, it emits ".align log2(N)", e.g. 3 to align to an 8 byte
      /// boundary.
      bool AlignmentIsInBytes;                 // Defaults to true
  
      /// TextAlignFillValue - If non-zero, this is used to fill the executable
      /// space created as the result of a alignment directive.
      unsigned TextAlignFillValue;             // Defaults to 0
  
      //===--- Global Variable Emission Directives --------------------------===//
  
      /// GlobalDirective - This is the directive used to declare a global entity.
      ///
      const char *GlobalDirective;             // Defaults to NULL.
  
      /// ExternDirective - This is the directive used to declare external
      /// globals.
      ///
      const char *ExternDirective;             // Defaults to NULL.
  
      /// HasSetDirective - True if the assembler supports the .set directive.
      bool HasSetDirective;                    // Defaults to true.
  
      /// HasAggressiveSymbolFolding - False if the assembler requires that we use
      /// Lc = a - b
      /// .long Lc
      /// instead of
      /// .long a - b
      bool HasAggressiveSymbolFolding;           // Defaults to true.
  
      /// COMMDirectiveAlignmentIsInBytes - True is .comm's and .lcomms optional
      /// alignment is to be specified in bytes instead of log2(n).
      bool COMMDirectiveAlignmentIsInBytes;    // Defaults to true;
  
      /// LCOMMDirectiveAlignment - Describes if the .lcomm directive for the
      /// target supports an alignment argument and how it is interpreted.
      LCOMM::LCOMMType LCOMMDirectiveAlignmentType; // Defaults to NoAlignment.
  
      /// HasDotTypeDotSizeDirective - True if the target has .type and .size
      /// directives, this is true for most ELF targets.
      bool HasDotTypeDotSizeDirective;         // Defaults to true.
  
      /// HasSingleParameterDotFile - True if the target has a single parameter
      /// .file directive, this is true for ELF targets.
      bool HasSingleParameterDotFile;          // Defaults to true.
  
      /// HasNoDeadStrip - True if this target supports the MachO .no_dead_strip
      /// directive.
      bool HasNoDeadStrip;                     // Defaults to false.
  
      /// HasSymbolResolver - True if this target supports the MachO
      /// .symbol_resolver directive.
      bool HasSymbolResolver;                     // Defaults to false.
  
      /// WeakRefDirective - This directive, if non-null, is used to declare a
      /// global as being a weak undefined symbol.
      const char *WeakRefDirective;            // Defaults to NULL.
  
      /// WeakDefDirective - This directive, if non-null, is used to declare a
      /// global as being a weak defined symbol.
      const char *WeakDefDirective;            // Defaults to NULL.
  
      /// LinkOnceDirective - This directive, if non-null is used to declare a
      /// global as being a weak defined symbol.  This is used on cygwin/mingw.
      const char *LinkOnceDirective;           // Defaults to NULL.
  
      /// HiddenVisibilityAttr - This attribute, if not MCSA_Invalid, is used to
      /// declare a symbol as having hidden visibility.
      MCSymbolAttr HiddenVisibilityAttr;       // Defaults to MCSA_Hidden.
  
      /// HiddenDeclarationVisibilityAttr - This attribute, if not MCSA_Invalid,
      /// is used to declare an undefined symbol as having hidden visibility.
      MCSymbolAttr HiddenDeclarationVisibilityAttr;   // Defaults to MCSA_Hidden.
  
  
      /// ProtectedVisibilityAttr - This attribute, if not MCSA_Invalid, is used
      /// to declare a symbol as having protected visibility.
      MCSymbolAttr ProtectedVisibilityAttr;    // Defaults to MCSA_Protected
  
      //===--- Dwarf Emission Directives -----------------------------------===//
  
      /// HasLEB128 - True if target asm supports leb128 directives.
      bool HasLEB128;                          // Defaults to false.
  
      /// SupportsDebugInformation - True if target supports emission of debugging
      /// information.
      bool SupportsDebugInformation;           // Defaults to false.
  
      /// SupportsExceptionHandling - True if target supports exception handling.
      ExceptionHandling::ExceptionsType ExceptionsType; // Defaults to None
  
      /// DwarfUsesInlineInfoSection - True if DwarfDebugInlineSection is used to
      /// encode inline subroutine information.
      bool DwarfUsesInlineInfoSection;         // Defaults to false.
  
      /// DwarfUsesRelocationsAcrossSections - True if Dwarf2 output generally
      /// uses relocations for references to other .debug_* sections.
      bool DwarfUsesRelocationsAcrossSections;
  
      /// DwarfRegNumForCFI - True if dwarf register numbers are printed
      /// instead of symbolic register names in .cfi_* directives.
      bool DwarfRegNumForCFI;  // Defaults to false;
  
      //===--- Prologue State ----------------------------------------------===//
  
      std::vector<MCCFIInstruction> InitialFrameState;
  
    public:
      explicit MCAsmInfo();
      virtual ~MCAsmInfo();
  
      // FIXME: move these methods to DwarfPrinter when the JIT stops using them.
      static unsigned getSLEB128Size(int Value);
      static unsigned getULEB128Size(unsigned Value);
  
      /// getPointerSize - Get the pointer size in bytes.
      unsigned getPointerSize() const {
        return PointerSize;
      }
  
      /// getCalleeSaveStackSlotSize - Get the callee-saved register stack slot
      /// size in bytes.
      unsigned getCalleeSaveStackSlotSize() const {
        return CalleeSaveStackSlotSize;
      }
  
      /// isLittleEndian - True if the target is little endian.
      bool isLittleEndian() const {
        return IsLittleEndian;
      }
  
      /// isStackGrowthDirectionUp - True if target stack grow up.
      bool isStackGrowthDirectionUp() const {
        return StackGrowsUp;
      }
  
      bool hasSubsectionsViaSymbols() const { return HasSubsectionsViaSymbols; }
  
      // Data directive accessors.
      //
      const char *getData8bitsDirective(unsigned AS = 0) const {
        return AS == 0 ? Data8bitsDirective : getDataASDirective(8, AS);
      }
      const char *getData16bitsDirective(unsigned AS = 0) const {
        return AS == 0 ? Data16bitsDirective : getDataASDirective(16, AS);
      }
      const char *getData32bitsDirective(unsigned AS = 0) const {
        return AS == 0 ? Data32bitsDirective : getDataASDirective(32, AS);
      }
      const char *getData64bitsDirective(unsigned AS = 0) const {
        return AS == 0 ? Data64bitsDirective : getDataASDirective(64, AS);
      }
      const char *getGPRel64Directive() const { return GPRel64Directive; }
      const char *getGPRel32Directive() const { return GPRel32Directive; }
  
      /// getNonexecutableStackSection - Targets can implement this method to
      /// specify a section to switch to if the translation unit doesn't have any
      /// trampolines that require an executable stack.
      virtual const MCSection *getNonexecutableStackSection(MCContext &Ctx) const{
        return 0;
      }
  
      virtual const MCExpr *
      getExprForPersonalitySymbol(const MCSymbol *Sym,
                                  unsigned Encoding,
                                  MCStreamer &Streamer) const;
  
      const MCExpr *
      getExprForFDESymbol(const MCSymbol *Sym,
                          unsigned Encoding,
                          MCStreamer &Streamer) const;
  
      bool usesSunStyleELFSectionSwitchSyntax() const {
        return SunStyleELFSectionSwitchSyntax;
      }
  
      bool usesELFSectionDirectiveForBSS() const {
        return UsesELFSectionDirectiveForBSS;
      }
  
      bool hasMicrosoftFastStdCallMangling() const {
        return HasMicrosoftFastStdCallMangling;
      }
  
      bool needsDwarfSectionOffsetDirective() const {
        return NeedsDwarfSectionOffsetDirective;
      }
  
      // Accessors.
      //
      bool hasMachoZeroFillDirective() const { return HasMachoZeroFillDirective; }
      bool hasMachoTBSSDirective() const { return HasMachoTBSSDirective; }
      bool hasStaticCtorDtorReferenceInStaticMode() const {
        return HasStaticCtorDtorReferenceInStaticMode;
      }
      bool getLinkerRequiresNonEmptyDwarfLines() const {
        return LinkerRequiresNonEmptyDwarfLines;
      }
      unsigned getMaxInstLength() const {
        return MaxInstLength;
      }
      unsigned getMinInstAlignment() const {
        return MinInstAlignment;
      }
      const char *getPCSymbol() const {
        return PCSymbol;
      }
      const char *getSeparatorString() const {
        return SeparatorString;
      }
      unsigned getCommentColumn() const {
        return CommentColumn;
      }
      const char *getCommentString() const {
        return CommentString;
      }
      const char *getLabelSuffix() const {
        return LabelSuffix;
      }
  
      const char *getDebugLabelSuffix() const {
        return DebugLabelSuffix;
      }
  
      const char *getGlobalPrefix() const {
        return GlobalPrefix;
      }
      const char *getPrivateGlobalPrefix() const {
        return PrivateGlobalPrefix;
      }
      const char *getLinkerPrivateGlobalPrefix() const {
        return LinkerPrivateGlobalPrefix;
      }
      const char *getInlineAsmStart() const {
        return InlineAsmStart;
      }
      const char *getInlineAsmEnd() const {
        return InlineAsmEnd;
      }
      const char *getCode16Directive() const {
        return Code16Directive;
      }
      const char *getCode32Directive() const {
        return Code32Directive;
      }
      const char *getCode64Directive() const {
        return Code64Directive;
      }
      unsigned getAssemblerDialect() const {
        return AssemblerDialect;
      }
      bool doesAllowQuotesInName() const {
        return AllowQuotesInName;
      }
      bool doesAllowNameToStartWithDigit() const {
        return AllowNameToStartWithDigit;
      }
      bool doesAllowPeriodsInName() const {
        return AllowPeriodsInName;
      }
      bool doesAllowUTF8() const {
        return AllowUTF8;
      }
      bool doesSupportDataRegionDirectives() const {
        return UseDataRegionDirectives;
      }
      const char *getZeroDirective() const {
        return ZeroDirective;
      }
      const char *getAsciiDirective() const {
        return AsciiDirective;
      }
      const char *getAscizDirective() const {
        return AscizDirective;
      }
      const char *getAlignDirective() const {
        return AlignDirective;
      }
      bool getAlignmentIsInBytes() const {
        return AlignmentIsInBytes;
      }
      unsigned getTextAlignFillValue() const {
        return TextAlignFillValue;
      }
      const char *getGlobalDirective() const {
        return GlobalDirective;
      }
      const char *getExternDirective() const {
        return ExternDirective;
      }
      bool hasSetDirective() const { return HasSetDirective; }
      bool hasAggressiveSymbolFolding() const {
        return HasAggressiveSymbolFolding;
      }
      bool getCOMMDirectiveAlignmentIsInBytes() const {
        return COMMDirectiveAlignmentIsInBytes;
      }
      LCOMM::LCOMMType getLCOMMDirectiveAlignmentType() const {
        return LCOMMDirectiveAlignmentType;
      }
      bool hasDotTypeDotSizeDirective() const {return HasDotTypeDotSizeDirective;}
      bool hasSingleParameterDotFile() const { return HasSingleParameterDotFile; }
      bool hasNoDeadStrip() const { return HasNoDeadStrip; }
      bool hasSymbolResolver() const { return HasSymbolResolver; }
      const char *getWeakRefDirective() const { return WeakRefDirective; }
      const char *getWeakDefDirective() const { return WeakDefDirective; }
      const char *getLinkOnceDirective() const { return LinkOnceDirective; }
  
      MCSymbolAttr getHiddenVisibilityAttr() const { return HiddenVisibilityAttr;}
      MCSymbolAttr getHiddenDeclarationVisibilityAttr() const {
        return HiddenDeclarationVisibilityAttr;
      }
      MCSymbolAttr getProtectedVisibilityAttr() const {
        return ProtectedVisibilityAttr;
      }
      bool hasLEB128() const {
        return HasLEB128;
      }
      bool doesSupportDebugInformation() const {
        return SupportsDebugInformation;
      }
      bool doesSupportExceptionHandling() const {
        return ExceptionsType != ExceptionHandling::None;
      }
      ExceptionHandling::ExceptionsType getExceptionHandlingType() const {
        return ExceptionsType;
      }
      bool isExceptionHandlingDwarf() const {
        return
          (ExceptionsType == ExceptionHandling::DwarfCFI ||
           ExceptionsType == ExceptionHandling::ARM ||
           ExceptionsType == ExceptionHandling::Win64);
      }
      bool doesDwarfUseInlineInfoSection() const {
        return DwarfUsesInlineInfoSection;
      }
      bool doesDwarfUseRelocationsAcrossSections() const {
        return DwarfUsesRelocationsAcrossSections;
      }
      bool useDwarfRegNumForCFI() const {
        return DwarfRegNumForCFI;
      }
  
      void addInitialFrameState(const MCCFIInstruction &Inst) {
        InitialFrameState.push_back(Inst);
      }
  
      const std::vector<MCCFIInstruction> &getInitialFrameState() const {
        return InitialFrameState;
      }
    };
  }
  
  #endif
  