MCAsmInfo.h revision 3eb4be0ace6263f35a2f3aae9e964a752ebe55af 
1//===-- llvm/MC/MCAsmInfo.h - Asm info --------------------------*- C++ -*-===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10// This file contains a class to be used as the basis for target specific
11// asm writers.  This class primarily takes care of global printing constants,
12// which are used in very similar ways across all targets.
13//
14//===----------------------------------------------------------------------===//
15
16#ifndef LLVM_TARGET_ASM_INFO_H
17#define LLVM_TARGET_ASM_INFO_H
18
19#include "llvm/MC/MachineLocation.h"
20#include "llvm/MC/MCDirectives.h"
21#include <cassert>
22#include <vector>
23
24namespace llvm {
25  class MCExpr;
26  class MCSection;
27  class MCStreamer;
28  class MCSymbol;
29  class MCContext;
30
31  namespace ExceptionHandling {
32    enum ExceptionsType { None, DwarfCFI, SjLj, ARM, Win64 };
33  }
34
35  namespace LCOMM {
36    enum LCOMMType { None, NoAlignment, ByteAlignment };
37  }
38
39  /// MCAsmInfo - This class is intended to be used as a base class for asm
40  /// properties and features specific to the target.
41  class MCAsmInfo {
42  protected:
43    //===------------------------------------------------------------------===//
44    // Properties to be set by the target writer, used to configure asm printer.
45    //
46
47    /// PointerSize - Pointer size in bytes.
48    ///               Default is 4.
49    unsigned PointerSize;
50
51    /// IsLittleEndian - True if target is little endian.
52    ///                  Default is true.
53    bool IsLittleEndian;
54
55    /// StackGrowsUp - True if target stack grow up.
56    ///                Default is false.
57    bool StackGrowsUp;
58
59    /// HasSubsectionsViaSymbols - True if this target has the MachO
60    /// .subsections_via_symbols directive.
61    bool HasSubsectionsViaSymbols;           // Default is false.
62
63    /// HasMachoZeroFillDirective - True if this is a MachO target that supports
64    /// the macho-specific .zerofill directive for emitting BSS Symbols.
65    bool HasMachoZeroFillDirective;               // Default is false.
66
67    /// HasMachoTBSSDirective - True if this is a MachO target that supports
68    /// the macho-specific .tbss directive for emitting thread local BSS Symbols
69    bool HasMachoTBSSDirective;                 // Default is false.
70
71    /// HasStaticCtorDtorReferenceInStaticMode - True if the compiler should
72    /// emit a ".reference .constructors_used" or ".reference .destructors_used"
73    /// directive after the a static ctor/dtor list.  This directive is only
74    /// emitted in Static relocation model.
75    bool HasStaticCtorDtorReferenceInStaticMode;  // Default is false.
76
77    /// LinkerRequiresNonEmptyDwarfLines - True if the linker has a bug and
78    /// requires that the debug_line section be of a minimum size. In practice
79    /// such a linker requires a non empty line sequence if a file is present.
80    bool LinkerRequiresNonEmptyDwarfLines; // Default to false.
81
82    /// MaxInstLength - This is the maximum possible length of an instruction,
83    /// which is needed to compute the size of an inline asm.
84    unsigned MaxInstLength;                  // Defaults to 4.
85
86    /// PCSymbol - The symbol used to represent the current PC.  Used in PC
87    /// relative expressions.
88    const char *PCSymbol;                    // Defaults to "$".
89
90    /// SeparatorString - This string, if specified, is used to separate
91    /// instructions from each other when on the same line.
92    const char *SeparatorString;             // Defaults to ';'
93
94    /// CommentColumn - This indicates the comment num (zero-based) at
95    /// which asm comments should be printed.
96    unsigned CommentColumn;                  // Defaults to 40
97
98    /// CommentString - This indicates the comment character used by the
99    /// assembler.
100    const char *CommentString;               // Defaults to "#"
101
102    /// LabelSuffix - This is appended to emitted labels.
103    const char *LabelSuffix;                 // Defaults to ":"
104
105    /// GlobalPrefix - If this is set to a non-empty string, it is prepended
106    /// onto all global symbols.  This is often used for "_" or ".".
107    const char *GlobalPrefix;                // Defaults to ""
108
109    /// PrivateGlobalPrefix - This prefix is used for globals like constant
110    /// pool entries that are completely private to the .s file and should not
111    /// have names in the .o file.  This is often "." or "L".
112    const char *PrivateGlobalPrefix;         // Defaults to "."
113
114    /// LinkerPrivateGlobalPrefix - This prefix is used for symbols that should
115    /// be passed through the assembler but be removed by the linker.  This
116    /// is "l" on Darwin, currently used for some ObjC metadata.
117    const char *LinkerPrivateGlobalPrefix;   // Defaults to ""
118
119    /// InlineAsmStart/End - If these are nonempty, they contain a directive to
120    /// emit before and after an inline assembly statement.
121    const char *InlineAsmStart;              // Defaults to "#APP\n"
122    const char *InlineAsmEnd;                // Defaults to "#NO_APP\n"
123
124    /// Code16Directive, Code32Directive, Code64Directive - These are assembly
125    /// directives that tells the assembler to interpret the following
126    /// instructions differently.
127    const char *Code16Directive;             // Defaults to ".code16"
128    const char *Code32Directive;             // Defaults to ".code32"
129    const char *Code64Directive;             // Defaults to ".code64"
130
131    /// AssemblerDialect - Which dialect of an assembler variant to use.
132    unsigned AssemblerDialect;               // Defaults to 0
133
134    /// AllowQuotesInName - This is true if the assembler allows for complex
135    /// symbol names to be surrounded in quotes.  This defaults to false.
136    bool AllowQuotesInName;
137
138    /// AllowNameToStartWithDigit - This is true if the assembler allows symbol
139    /// names to start with a digit (e.g., "0x0021").  This defaults to false.
140    bool AllowNameToStartWithDigit;
141
142    /// AllowPeriodsInName - This is true if the assembler allows periods in
143    /// symbol names.  This defaults to true.
144    bool AllowPeriodsInName;
145
146    //===--- Data Emission Directives -------------------------------------===//
147
148    /// ZeroDirective - this should be set to the directive used to get some
149    /// number of zero bytes emitted to the current section.  Common cases are
150    /// "\t.zero\t" and "\t.space\t".  If this is set to null, the
151    /// Data*bitsDirective's will be used to emit zero bytes.
152    const char *ZeroDirective;               // Defaults to "\t.zero\t"
153
154    /// AsciiDirective - This directive allows emission of an ascii string with
155    /// the standard C escape characters embedded into it.
156    const char *AsciiDirective;              // Defaults to "\t.ascii\t"
157
158    /// AscizDirective - If not null, this allows for special handling of
159    /// zero terminated strings on this target.  This is commonly supported as
160    /// ".asciz".  If a target doesn't support this, it can be set to null.
161    const char *AscizDirective;              // Defaults to "\t.asciz\t"
162
163    /// DataDirectives - These directives are used to output some unit of
164    /// integer data to the current section.  If a data directive is set to
165    /// null, smaller data directives will be used to emit the large sizes.
166    const char *Data8bitsDirective;          // Defaults to "\t.byte\t"
167    const char *Data16bitsDirective;         // Defaults to "\t.short\t"
168    const char *Data32bitsDirective;         // Defaults to "\t.long\t"
169    const char *Data64bitsDirective;         // Defaults to "\t.quad\t"
170
171    /// [Data|Code]Begin - These magic labels are used to marked a region as
172    /// data or code, and are used to provide additional information for
173    /// correct disassembly on targets that like to mix data and code within
174    /// a segment.  These labels will be implicitly suffixed by the streamer
175    /// to give them unique names.
176    const char *DataBegin;                   // Defaults to "$d."
177    const char *CodeBegin;                   // Defaults to "$a."
178    const char *JT8Begin;                    // Defaults to "$a."
179    const char *JT16Begin;                   // Defaults to "$a."
180    const char *JT32Begin;                   // Defaults to "$a."
181    bool SupportsDataRegions;
182
183    /// GPRel32Directive - if non-null, a directive that is used to emit a word
184    /// which should be relocated as a 32-bit GP-relative offset, e.g. .gpword
185    /// on Mips or .gprel32 on Alpha.
186    const char *GPRel32Directive;            // Defaults to NULL.
187
188    /// getDataASDirective - Return the directive that should be used to emit
189    /// data of the specified size to the specified numeric address space.
190    virtual const char *getDataASDirective(unsigned Size, unsigned AS) const {
191      assert(AS != 0 && "Don't know the directives for default addr space");
192      return 0;
193    }
194
195    /// SunStyleELFSectionSwitchSyntax - This is true if this target uses "Sun
196    /// Style" syntax for section switching ("#alloc,#write" etc) instead of the
197    /// normal ELF syntax (,"a,w") in .section directives.
198    bool SunStyleELFSectionSwitchSyntax;     // Defaults to false.
199
200    /// UsesELFSectionDirectiveForBSS - This is true if this target uses ELF
201    /// '.section' directive before the '.bss' one. It's used for PPC/Linux
202    /// which doesn't support the '.bss' directive only.
203    bool UsesELFSectionDirectiveForBSS;      // Defaults to false.
204
205    /// HasMicrosoftFastStdCallMangling - True if this target uses microsoft
206    /// style mangling for functions with X86_StdCall/X86_FastCall calling
207    /// convention.
208    bool HasMicrosoftFastStdCallMangling;    // Defaults to false.
209
210    //===--- Alignment Information ----------------------------------------===//
211
212    /// AlignDirective - The directive used to emit round up to an alignment
213    /// boundary.
214    ///
215    const char *AlignDirective;              // Defaults to "\t.align\t"
216
217    /// AlignmentIsInBytes - If this is true (the default) then the asmprinter
218    /// emits ".align N" directives, where N is the number of bytes to align to.
219    /// Otherwise, it emits ".align log2(N)", e.g. 3 to align to an 8 byte
220    /// boundary.
221    bool AlignmentIsInBytes;                 // Defaults to true
222
223    /// TextAlignFillValue - If non-zero, this is used to fill the executable
224    /// space created as the result of a alignment directive.
225    unsigned TextAlignFillValue;             // Defaults to 0
226
227    //===--- Global Variable Emission Directives --------------------------===//
228
229    /// GlobalDirective - This is the directive used to declare a global entity.
230    ///
231    const char *GlobalDirective;             // Defaults to NULL.
232
233    /// ExternDirective - This is the directive used to declare external
234    /// globals.
235    ///
236    const char *ExternDirective;             // Defaults to NULL.
237
238    /// HasSetDirective - True if the assembler supports the .set directive.
239    bool HasSetDirective;                    // Defaults to true.
240
241    /// HasAggressiveSymbolFolding - False if the assembler requires that we use
242    /// Lc = a - b
243    /// .long Lc
244    /// instead of
245    /// .long a - b
246    bool HasAggressiveSymbolFolding;           // Defaults to true.
247
248    /// LCOMMDirectiveType - Describes if the target supports the .lcomm
249    /// directive and whether it has an alignment parameter.
250    LCOMM::LCOMMType LCOMMDirectiveType;     // Defaults to LCOMM::None.
251
252    /// COMMDirectiveAlignmentIsInBytes - True is COMMDirective's optional
253    /// alignment is to be specified in bytes instead of log2(n).
254    bool COMMDirectiveAlignmentIsInBytes;    // Defaults to true;
255
256    /// HasDotTypeDotSizeDirective - True if the target has .type and .size
257    /// directives, this is true for most ELF targets.
258    bool HasDotTypeDotSizeDirective;         // Defaults to true.
259
260    /// HasSingleParameterDotFile - True if the target has a single parameter
261    /// .file directive, this is true for ELF targets.
262    bool HasSingleParameterDotFile;          // Defaults to true.
263
264    /// HasNoDeadStrip - True if this target supports the MachO .no_dead_strip
265    /// directive.
266    bool HasNoDeadStrip;                     // Defaults to false.
267
268    /// HasSymbolResolver - True if this target supports the MachO
269    /// .symbol_resolver directive.
270    bool HasSymbolResolver;                     // Defaults to false.
271
272    /// WeakRefDirective - This directive, if non-null, is used to declare a
273    /// global as being a weak undefined symbol.
274    const char *WeakRefDirective;            // Defaults to NULL.
275
276    /// WeakDefDirective - This directive, if non-null, is used to declare a
277    /// global as being a weak defined symbol.
278    const char *WeakDefDirective;            // Defaults to NULL.
279
280    /// LinkOnceDirective - This directive, if non-null is used to declare a
281    /// global as being a weak defined symbol.  This is used on cygwin/mingw.
282    const char *LinkOnceDirective;           // Defaults to NULL.
283
284    /// HiddenVisibilityAttr - This attribute, if not MCSA_Invalid, is used to
285    /// declare a symbol as having hidden visibility.
286    MCSymbolAttr HiddenVisibilityAttr;       // Defaults to MCSA_Hidden.
287
288    /// HiddenDeclarationVisibilityAttr - This attribute, if not MCSA_Invalid,
289    /// is used to declare an undefined symbol as having hidden visibility.
290    MCSymbolAttr HiddenDeclarationVisibilityAttr;   // Defaults to MCSA_Hidden.
291
292
293    /// ProtectedVisibilityAttr - This attribute, if not MCSA_Invalid, is used
294    /// to declare a symbol as having protected visibility.
295    MCSymbolAttr ProtectedVisibilityAttr;    // Defaults to MCSA_Protected
296
297    //===--- Dwarf Emission Directives -----------------------------------===//
298
299    /// HasLEB128 - True if target asm supports leb128 directives.
300    bool HasLEB128;                          // Defaults to false.
301
302    /// SupportsDebugInformation - True if target supports emission of debugging
303    /// information.
304    bool SupportsDebugInformation;           // Defaults to false.
305
306    /// SupportsExceptionHandling - True if target supports exception handling.
307    ExceptionHandling::ExceptionsType ExceptionsType; // Defaults to None
308
309    /// DwarfUsesInlineInfoSection - True if DwarfDebugInlineSection is used to
310    /// encode inline subroutine information.
311    bool DwarfUsesInlineInfoSection;         // Defaults to false.
312
313    /// DwarfSectionOffsetDirective - Special section offset directive.
314    const char* DwarfSectionOffsetDirective; // Defaults to NULL
315
316    /// DwarfRequiresRelocationForSectionOffset - True if we need to produce a
317    /// relocation when we want a section offset in dwarf.
318    bool DwarfRequiresRelocationForSectionOffset;  // Defaults to true;
319
320    /// DwarfUsesLabelOffsetDifference - True if Dwarf2 output can
321    /// use EmitLabelOffsetDifference.
322    bool DwarfUsesLabelOffsetForRanges;
323
324    /// DwarfUsesRelocationsForStringPool - True if this Dwarf output must use
325    /// relocations to refer to entries in the string pool.
326    bool DwarfUsesRelocationsForStringPool;
327
328    /// DwarfRegNumForCFI - True if dwarf register numbers are printed
329    /// instead of symbolic register names in .cfi_* directives.
330    bool DwarfRegNumForCFI;  // Defaults to false;
331
332    //===--- CBE Asm Translation Table -----------------------------------===//
333
334    const char *const *AsmTransCBE;          // Defaults to empty
335
336    //===--- Prologue State ----------------------------------------------===//
337
338    std::vector<MachineMove> InitialFrameState;
339
340  public:
341    explicit MCAsmInfo();
342    virtual ~MCAsmInfo();
343
344    // FIXME: move these methods to DwarfPrinter when the JIT stops using them.
345    static unsigned getSLEB128Size(int Value);
346    static unsigned getULEB128Size(unsigned Value);
347
348    /// getPointerSize - Get the pointer size in bytes.
349    unsigned getPointerSize() const {
350      return PointerSize;
351    }
352
353    /// islittleendian - True if the target is little endian.
354    bool isLittleEndian() const {
355      return IsLittleEndian;
356    }
357
358    /// isStackGrowthDirectionUp - True if target stack grow up.
359    bool isStackGrowthDirectionUp() const {
360      return StackGrowsUp;
361    }
362
363    bool hasSubsectionsViaSymbols() const { return HasSubsectionsViaSymbols; }
364
365    // Data directive accessors.
366    //
367    const char *getData8bitsDirective(unsigned AS = 0) const {
368      return AS == 0 ? Data8bitsDirective : getDataASDirective(8, AS);
369    }
370    const char *getData16bitsDirective(unsigned AS = 0) const {
371      return AS == 0 ? Data16bitsDirective : getDataASDirective(16, AS);
372    }
373    const char *getData32bitsDirective(unsigned AS = 0) const {
374      return AS == 0 ? Data32bitsDirective : getDataASDirective(32, AS);
375    }
376    const char *getData64bitsDirective(unsigned AS = 0) const {
377      return AS == 0 ? Data64bitsDirective : getDataASDirective(64, AS);
378    }
379    const char *getGPRel32Directive() const { return GPRel32Directive; }
380
381    /// [Code|Data]Begin label name accessors.
382    const char *getCodeBeginLabelName() const { return CodeBegin; }
383    const char *getDataBeginLabelName() const { return DataBegin; }
384    const char *getJumpTable8BeginLabelName() const { return JT8Begin; }
385    const char *getJumpTable16BeginLabelName() const { return JT16Begin; }
386    const char *getJumpTable32BeginLabelName() const { return JT32Begin; }
387    bool getSupportsDataRegions() const { return SupportsDataRegions; }
388
389    /// getNonexecutableStackSection - Targets can implement this method to
390    /// specify a section to switch to if the translation unit doesn't have any
391    /// trampolines that require an executable stack.
392    virtual const MCSection *getNonexecutableStackSection(MCContext &Ctx) const{
393      return 0;
394    }
395
396    virtual const MCExpr *
397    getExprForPersonalitySymbol(const MCSymbol *Sym,
398                                unsigned Encoding,
399                                MCStreamer &Streamer) const;
400
401    const MCExpr *
402    getExprForFDESymbol(const MCSymbol *Sym,
403                        unsigned Encoding,
404                        MCStreamer &Streamer) const;
405
406    bool usesSunStyleELFSectionSwitchSyntax() const {
407      return SunStyleELFSectionSwitchSyntax;
408    }
409
410    bool usesELFSectionDirectiveForBSS() const {
411      return UsesELFSectionDirectiveForBSS;
412    }
413
414    bool hasMicrosoftFastStdCallMangling() const {
415      return HasMicrosoftFastStdCallMangling;
416    }
417
418    // Accessors.
419    //
420    bool hasMachoZeroFillDirective() const { return HasMachoZeroFillDirective; }
421    bool hasMachoTBSSDirective() const { return HasMachoTBSSDirective; }
422    bool hasStaticCtorDtorReferenceInStaticMode() const {
423      return HasStaticCtorDtorReferenceInStaticMode;
424    }
425    bool getLinkerRequiresNonEmptyDwarfLines() const {
426      return LinkerRequiresNonEmptyDwarfLines;
427    }
428    unsigned getMaxInstLength() const {
429      return MaxInstLength;
430    }
431    const char *getPCSymbol() const {
432      return PCSymbol;
433    }
434    const char *getSeparatorString() const {
435      return SeparatorString;
436    }
437    unsigned getCommentColumn() const {
438      return CommentColumn;
439    }
440    const char *getCommentString() const {
441      return CommentString;
442    }
443    const char *getLabelSuffix() const {
444      return LabelSuffix;
445    }
446    const char *getGlobalPrefix() const {
447      return GlobalPrefix;
448    }
449    const char *getPrivateGlobalPrefix() const {
450      return PrivateGlobalPrefix;
451    }
452    const char *getLinkerPrivateGlobalPrefix() const {
453      return LinkerPrivateGlobalPrefix;
454    }
455    const char *getInlineAsmStart() const {
456      return InlineAsmStart;
457    }
458    const char *getInlineAsmEnd() const {
459      return InlineAsmEnd;
460    }
461    const char *getCode16Directive() const {
462      return Code16Directive;
463    }
464    const char *getCode32Directive() const {
465      return Code32Directive;
466    }
467    const char *getCode64Directive() const {
468      return Code64Directive;
469    }
470    unsigned getAssemblerDialect() const {
471      return AssemblerDialect;
472    }
473    bool doesAllowQuotesInName() const {
474      return AllowQuotesInName;
475    }
476    bool doesAllowNameToStartWithDigit() const {
477      return AllowNameToStartWithDigit;
478    }
479    bool doesAllowPeriodsInName() const {
480      return AllowPeriodsInName;
481    }
482    const char *getZeroDirective() const {
483      return ZeroDirective;
484    }
485    const char *getAsciiDirective() const {
486      return AsciiDirective;
487    }
488    const char *getAscizDirective() const {
489      return AscizDirective;
490    }
491    const char *getAlignDirective() const {
492      return AlignDirective;
493    }
494    bool getAlignmentIsInBytes() const {
495      return AlignmentIsInBytes;
496    }
497    unsigned getTextAlignFillValue() const {
498      return TextAlignFillValue;
499    }
500    const char *getGlobalDirective() const {
501      return GlobalDirective;
502    }
503    const char *getExternDirective() const {
504      return ExternDirective;
505    }
506    bool hasSetDirective() const { return HasSetDirective; }
507    bool hasAggressiveSymbolFolding() const {
508      return HasAggressiveSymbolFolding;
509    }
510    LCOMM::LCOMMType getLCOMMDirectiveType() const {
511      return LCOMMDirectiveType;
512    }
513    bool hasDotTypeDotSizeDirective() const {return HasDotTypeDotSizeDirective;}
514    bool getCOMMDirectiveAlignmentIsInBytes() const {
515      return COMMDirectiveAlignmentIsInBytes;
516    }
517    bool hasSingleParameterDotFile() const { return HasSingleParameterDotFile; }
518    bool hasNoDeadStrip() const { return HasNoDeadStrip; }
519    bool hasSymbolResolver() const { return HasSymbolResolver; }
520    const char *getWeakRefDirective() const { return WeakRefDirective; }
521    const char *getWeakDefDirective() const { return WeakDefDirective; }
522    const char *getLinkOnceDirective() const { return LinkOnceDirective; }
523
524    MCSymbolAttr getHiddenVisibilityAttr() const { return HiddenVisibilityAttr;}
525    MCSymbolAttr getHiddenDeclarationVisibilityAttr() const {
526      return HiddenDeclarationVisibilityAttr;
527    }
528    MCSymbolAttr getProtectedVisibilityAttr() const {
529      return ProtectedVisibilityAttr;
530    }
531    bool hasLEB128() const {
532      return HasLEB128;
533    }
534    bool doesSupportDebugInformation() const {
535      return SupportsDebugInformation;
536    }
537    bool doesSupportExceptionHandling() const {
538      return ExceptionsType != ExceptionHandling::None;
539    }
540    ExceptionHandling::ExceptionsType getExceptionHandlingType() const {
541      return ExceptionsType;
542    }
543    bool isExceptionHandlingDwarf() const {
544      return
545        (ExceptionsType == ExceptionHandling::DwarfCFI ||
546         ExceptionsType == ExceptionHandling::ARM ||
547         ExceptionsType == ExceptionHandling::Win64);
548    }
549    bool doesDwarfUsesInlineInfoSection() const {
550      return DwarfUsesInlineInfoSection;
551    }
552    const char *getDwarfSectionOffsetDirective() const {
553      return DwarfSectionOffsetDirective;
554    }
555    bool doesDwarfRequireRelocationForSectionOffset() const {
556      return DwarfRequiresRelocationForSectionOffset;
557    }
558    bool doesDwarfUsesLabelOffsetForRanges() const {
559      return DwarfUsesLabelOffsetForRanges;
560    }
561    bool doesDwarfUseRelocationsForStringPool() const {
562      return DwarfUsesRelocationsForStringPool;
563    }
564    bool useDwarfRegNumForCFI() const {
565      return DwarfRegNumForCFI;
566    }
567    const char *const *getAsmCBE() const {
568      return AsmTransCBE;
569    }
570
571    void addInitialFrameState(MCSymbol *label, const MachineLocation &D,
572                              const MachineLocation &S) {
573      InitialFrameState.push_back(MachineMove(label, D, S));
574    }
575    const std::vector<MachineMove> &getInitialFrameState() const {
576      return InitialFrameState;
577    }
578  };
579}
580
581#endif
582