path: root/include/llvm/Target/TargetAsmInfo.h

//===-- llvm/Target/TargetAsmInfo.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_TARGET_ASM_INFO_H
#define LLVM_TARGET_ASM_INFO_H

#include "llvm/CodeGen/MachineFunctionPass.h"
#include "llvm/Support/DataTypes.h"

namespace llvm {
  // DWARF encoding query type
  namespace DwarfEncoding {
    enum Target {
      Data       = 0,
      CodeLabels = 1,
      Functions  = 2
    };
  }

  class TargetMachine;
  class CallInst;

  /// TargetAsmInfo - This class is intended to be used as a base class for asm
  /// properties and features specific to the target.
  class TargetAsmInfo {
  protected:
    //===------------------------------------------------------------------===//
    // Properties to be set by the target writer, used to configure asm printer.
    //
    
    /// TextSection - Section directive for standard text.
    ///
    const char *TextSection;              // Defaults to ".text".
    
    /// DataSection - Section directive for standard data.
    ///
    const char *DataSection;              // Defaults to ".data".

    /// BSSSection - Section directive for uninitialized data.  Null if this
    /// target doesn't support a BSS section.
    ///
    const char *BSSSection;               // Default to ".bss".

    /// TLSDataSection - Section directive for Thread Local data.
    ///
    const char *TLSDataSection;// Defaults to ".section .tdata,"awT",@progbits".

    /// TLSBSSSection - Section directive for Thread Local uninitialized data.
    /// Null if this target doesn't support a BSS section.
    ///
    const char *TLSBSSSection;// Default to ".section .tbss,"awT",@nobits".

    /// ZeroFillDirective - Directive for emitting a global to the ZeroFill
    /// section on this target.  Null if this target doesn't support zerofill.
    const char *ZeroFillDirective;        // Default is null.
    
    /// NonexecutableStackDirective - Directive for declaring to the
    /// linker and beyond that the emitted code does not require stack
    /// memory to be executable.
    const char *NonexecutableStackDirective; // Default is null.

    /// NeedsSet - True if target asm treats expressions in data directives
    /// as linktime-relocatable.  For assembly-time computation, we need to
    /// use a .set.  Thus:
    /// .set w, x-y
    /// .long w
    /// is computed at assembly time, while
    /// .long x-y
    /// is relocated if the relative locations of x and y change at linktime.
    /// We want both these things in different places.
    bool NeedsSet;                        // Defaults 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.
    
    /// PCSymbol - The symbol used to represent the current PC.  Used in PC
    /// relative expressions.
    const char *PCSymbol;                 // Defaults to "$".

    /// SeparatorChar - This character, if specified, is used to separate
    /// instructions from each other when on the same line.  This is used to
    /// measure inline asm instructions.
    char SeparatorChar;                   // Defaults to ';'

    /// CommentString - This indicates the comment character used by the
    /// assembler.
    const char *CommentString;            // 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 .o file and should not
    /// have names in the .o file.  This is often "." or "L".
    const char *PrivateGlobalPrefix;      // Defaults to "."
    
    /// JumpTableSpecialLabelPrefix - If not null, a extra (dead) label is
    /// emitted before jump tables with the specified prefix.
    const char *JumpTableSpecialLabelPrefix;  // Default to null.
    
    /// GlobalVarAddrPrefix/Suffix - If these are nonempty, these strings
    /// will enclose any GlobalVariable (that isn't a function)
    ///
    const char *GlobalVarAddrPrefix;      // Defaults to ""
    const char *GlobalVarAddrSuffix;      // Defaults to ""

    /// FunctionAddrPrefix/Suffix - If these are nonempty, these strings
    /// will enclose any GlobalVariable that points to a function.
    /// For example, this is used by the IA64 backend to materialize
    /// function descriptors, by decorating the ".data8" object with the
    /// @verbatim @fptr( ) @endverbatim
    /// link-relocation operator.
    ///
    const char *FunctionAddrPrefix;       // Defaults to ""
    const char *FunctionAddrSuffix;       // Defaults to ""

    /// PersonalityPrefix/Suffix - If these are nonempty, these strings will
    /// enclose any personality function in the common frame section.
    /// 
    const char *PersonalityPrefix;        // Defaults to ""
    const char *PersonalitySuffix;        // Defaults to ""

    /// NeedsIndirectEncoding - If set, we need to set the indirect encoding bit
    /// for EH in Dwarf.
    /// 
    bool NeedsIndirectEncoding;           // Defaults to false

    /// 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"

    /// AssemblerDialect - Which dialect of an assembler variant to use.
    unsigned AssemblerDialect;            // Defaults to 0

    //===--- 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"
    const char *ZeroDirectiveSuffix;      // Defaults to ""

    /// 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"

    //===--- 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;

    //===--- Section Switching Directives ---------------------------------===//
    
    /// SwitchToSectionDirective - This is the directive used when we want to
    /// emit a global to an arbitrary section.  The section name is emited after
    /// this.
    const char *SwitchToSectionDirective; // Defaults to "\t.section\t"
    
    /// TextSectionStartSuffix - This is printed after each start of section
    /// directive for text sections.
    const char *TextSectionStartSuffix;   // Defaults to "".

    /// DataSectionStartSuffix - This is printed after each start of section
    /// directive for data sections.
    const char *DataSectionStartSuffix;   // Defaults to "".
    
    /// SectionEndDirectiveSuffix - If non-null, the asm printer will close each
    /// section with the section name and this suffix printed.
    const char *SectionEndDirectiveSuffix;// Defaults to null.
    
    /// ConstantPoolSection - This is the section that we SwitchToSection right
    /// before emitting the constant pool for a function.
    const char *ConstantPoolSection;      // Defaults to "\t.section .rodata"

    /// JumpTableDataSection - This is the section that we SwitchToSection right
    /// before emitting the jump tables for a function when the relocation model
    /// is not PIC.
    const char *JumpTableDataSection;     // Defaults to "\t.section .rodata"
    
    /// JumpTableDirective - if non-null, the directive to emit before a jump
    /// table.
    const char *JumpTableDirective;

    /// CStringSection - If not null, this allows for special handling of
    /// cstring constants (null terminated string that does not contain any
    /// other null bytes) on this target. This is commonly supported as
    /// ".cstring".
    const char *CStringSection;           // Defaults to NULL

    /// StaticCtorsSection - This is the directive that is emitted to switch to
    /// a section to emit the static constructor list.
    /// Defaults to "\t.section .ctors,\"aw\",@progbits".
    const char *StaticCtorsSection;

    /// StaticDtorsSection - This is the directive that is emitted to switch to
    /// a section to emit the static destructor list.
    /// Defaults to "\t.section .dtors,\"aw\",@progbits".
    const char *StaticDtorsSection;

    /// FourByteConstantSection, EightByteConstantSection,
    /// SixteenByteConstantSection - These are special sections where we place
    /// 4-, 8-, and 16- byte constant literals.
    const char *FourByteConstantSection;
    const char *EightByteConstantSection;
    const char *SixteenByteConstantSection;

    /// ReadOnlySection - This is the directive that is emitted to switch to a
    /// read-only section for constant data (e.g. data declared const,
    /// jump tables).
    const char *ReadOnlySection;          // Defaults to NULL

    //===--- Global Variable Emission Directives --------------------------===//
    
    /// GlobalDirective - This is the directive used to declare a global entity.
    ///
    const char *GlobalDirective;          // Defaults to NULL.
    
    /// SetDirective - This is the name of a directive that can be used to tell
    /// the assembler to set the value of a variable to some expression.
    const char *SetDirective;             // Defaults to null.
    
    /// LCOMMDirective - This is the name of a directive (if supported) that can
    /// be used to efficiently declare a local (internal) block of zero
    /// initialized data in the .bss/.data section.  The syntax expected is:
    /// @verbatim <LCOMMDirective> SYMBOLNAME LENGTHINBYTES, ALIGNMENT
    /// @endverbatim
    const char *LCOMMDirective;           // Defaults to null.
    
    const char *COMMDirective;            // Defaults to "\t.comm\t".

    /// COMMDirectiveTakesAlignment - True if COMMDirective take a third
    /// argument that specifies the alignment of the declaration.
    bool COMMDirectiveTakesAlignment;     // Defaults to true.
    
    /// HasDotTypeDotSizeDirective - True if the target has .type and .size
    /// directives, this is true for most ELF targets.
    bool