MCAsmInfo.h revision d7ef09bc9a6dea29a4ac4a45e722d479e8c50f6d 
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_MC_MCASMINFO_H
17#define LLVM_MC_MCASMINFO_H
18
19#include "llvm/MC/MCDirectives.h"
20#include "llvm/MC/MCDwarf.h"
21#include "llvm/MC/MachineLocation.h"
22#include <cassert>
23#include <vector>
24
25namespace llvm {
26  class MCExpr;
27  class MCSection;
28  class MCStreamer;
29  class MCSymbol;
30  class MCContext;
31
32  namespace ExceptionHandling {
33    enum ExceptionsType { None, DwarfCFI, SjLj, ARM, Win64 };
34  }
35
36  namespace LCOMM {
37    enum LCOMMType { NoAlignment, ByteAlignment, Log2Alignment };
38  }
39
40  /// MCAsmInfo - This class is intended to be used as a base class for asm
41  /// properties and features specific to the target.
42  class MCAsmInfo {
43  protected:
44    //===------------------------------------------------------------------===//
45    // Properties to be set by the target writer, used to configure asm printer.
46    //
47
48    /// PointerSize - Pointer size in bytes.
49    ///               Default is 4.
50    unsigned PointerSize;
51
52    /// CalleeSaveStackSlotSize - Size of the stack slot reserved for
53    ///                           callee-saved registers, in bytes.
54    ///                           Default is same as pointer size.
55    unsigned CalleeSaveStackSlotSize;
56
57    /// IsLittleEndian - True if target is little endian.
58    ///                  Default is true.
59    bool IsLittleEndian;
60
61    /// StackGrowsUp - True if target stack grow up.
62    ///                Default is false.
63    bool StackGrowsUp;
64
65    /// HasSubsectionsViaSymbols - True if this target has the MachO
66    /// .subsections_via_symbols directive.
67    bool HasSubsectionsViaSymbols;           // Default is false.
68
69    /// HasMachoZeroFillDirective - True if this is a MachO target that supports
70    /// the macho-specific .zerofill directive for emitting BSS Symbols.
71    bool HasMachoZeroFillDirective;               // Default is false.
72
73    /// HasMachoTBSSDirective - True if this is a MachO target that supports
74    /// the macho-specific .tbss directive for emitting thread local BSS Symbols
75    bool HasMachoTBSSDirective;                 // Default is false.
76
77    /// HasStaticCtorDtorReferenceInStaticMode - True if the compiler should
78    /// emit a ".reference .constructors_used" or ".reference .destructors_used"
79    /// directive after the a static ctor/dtor list.  This directive is only
80    /// emitted in Static relocation model.
81    bool HasStaticCtorDtorReferenceInStaticMode;  // Default is false.
82
83    /// LinkerRequiresNonEmptyDwarfLines - True if the linker has a bug and
84    /// requires that the debug_line section be of a minimum size. In practice
85    /// such a linker requires a non empty line sequence if a file is present.
86    bool LinkerRequiresNonEmptyDwarfLines; // Default to false.
87
88    /// MaxInstLength - This is the maximum possible length of an instruction,
89    /// which is needed to compute the size of an inline asm.
90    unsigned MaxInstLength;                  // Defaults to 4.
91
92    /// MinInstAlignment - Every possible instruction length is a multiple of
93    /// this value.  Factored out in .debug_frame and .debug_line.
94    unsigned MinInstAlignment;                  // Defaults to 1.
95
96    /// DollarIsPC - The '$' token, when not referencing an identifier or
97    /// constant, refers to the current PC.
98    bool DollarIsPC;                         // Defaults to false.
99
100    /// SeparatorString - This string, if specified, is used to separate
101    /// instructions from each other when on the same line.
102    const char *SeparatorString;             // Defaults to ';'
103
104    /// CommentColumn - This indicates the comment num (zero-based) at
105    /// which asm comments should be printed.
106    unsigned CommentColumn;                  // Defaults to 40
107
108    /// CommentString - This indicates the comment character used by the
109    /// assembler.
110    const char *CommentString;               // Defaults to "#"
111
112    /// LabelSuffix - This is appended to emitted labels.
113    const char *LabelSuffix;                 // Defaults to ":"
114
115    /// LabelSuffix - This is appended to emitted labels.
116    const char *DebugLabelSuffix;                 // Defaults to ":"
117
118    /// GlobalPrefix - If this is set to a non-empty string, it is prepended
119    /// onto all global symbols.  This is often used for "_" or ".".
120    const char *GlobalPrefix;                // Defaults to ""
121
122    /// PrivateGlobalPrefix - This prefix is used for globals like constant
123    /// pool entries that are completely private to the .s file and should not
124    /// have names in the .o file.  This is often "." or "L".
125    const char *PrivateGlobalPrefix;         // Defaults to "."
126
127    /// LinkerPrivateGlobalPrefix - This prefix is used for symbols that should
128    /// be passed through the assembler but be removed by the linker.  This
129    /// is "l" on Darwin, currently used for some ObjC metadata.
130    const char *LinkerPrivateGlobalPrefix;   // Defaults to ""
131
132    /// InlineAsmStart/End - If these are nonempty, they contain a directive to
133    /// emit before and after an inline assembly statement.
134    const char *InlineAsmStart;              // Defaults to "#APP\n"
135    const char *InlineAsmEnd;                // Defaults to "#NO_APP\n"
136
137    /// Code16Directive, Code32Directive, Code64Directive - These are assembly
138    /// directives that tells the assembler to interpret the following
139    /// instructions differently.
140    const char *Code16Directive;             // Defaults to ".code16"
141    const char *Code32Directive;             // Defaults to ".code32"
142    const char *Code64Directive;             // Defaults to ".code64"
143
144    /// AssemblerDialect - Which dialect of an assembler variant to use.
145    unsigned AssemblerDialect;               // Defaults to 0
146
147    /// AllowQuotesInName - This is true if the assembler allows for complex
148    /// symbol names to be surrounded in quotes.  This defaults to false.
149    bool AllowQuotesInName;
150
151    /// AllowNameToStartWithDigit - This is true if the assembler allows symbol
152    /// names to start with a digit (e.g., "0x0021").  This defaults to false.
153    bool AllowNameToStartWithDigit;
154
155    /// AllowPeriodsInName - This is true if the assembler allows periods in
156    /// symbol names.  This defaults to true.
157    bool AllowPeriodsInName;
158
159    /// \brief This is true if the assembler allows @ characters in symbol
160    /// names. Defaults to false.
161    bool AllowAtInName;
162
163    /// AllowUTF8 - This is true if the assembler accepts UTF-8 input.
164    // FIXME: Make this a more general encoding setting?
165    bool AllowUTF8;
166
167    /// UseDataRegionDirectives - This is true if data region markers should
168    /// be printed as ".data_region/.end_data_region" directives. If false,
169    /// use "$d/$a" labels instead.
170    bool UseDataRegionDirectives;
171
172    //===--- Data Emission Directives -------------------------------------===//
173
174    /// ZeroDirective - this should be set to the directive used to get some
175    /// number of zero bytes emitted to the current section.  Common cases are
176    /// "\t.zero\t" and "\t.space\t".  If this is set to null, the
177    /// Data*bitsDirective's will be used to emit zero bytes.
178    const char *ZeroDirective;               // Defaults to "\t.zero\t"
179
180    /// AsciiDirective - This directive allows emission of an ascii string with
181    /// the standard C escape characters embedded into it.
182    const char *AsciiDirective;              // Defaults to "\t.ascii\t"
183
184    /// AscizDirective - If not null, this allows for special handling of
185    /// zero terminated strings on this target.  This is commonly supported as
186    /// ".asciz".  If a target doesn't support this, it can be set to null.
187    const char *AscizDirective;              // Defaults to "\t.asciz\t"
188
189    /// DataDirectives - These directives are used to output some unit of
190    /// integer data to the current section.  If a data directive is set to
191    /// null, smaller data directives will be used to emit the large sizes.
192    const char *Data8bitsDirective;          // Defaults to "\t.byte\t"
193    const char *Data16bitsDirective;         // Defaults to "\t.short\t"
194    const char *Data32bitsDirective;         // Defaults to "\t.long\t"
195    const char *Data64bitsDirective;         // Defaults to "\t.quad\t"
196
197    /// GPRel64Directive - if non-null, a directive that is used to emit a word
198    /// which should be relocated as a 64-bit GP-relative offset, e.g. .gpdword
199    /// on Mips.
200    const char *GPRel64Directive;            // Defaults to NULL.
201
202    /// GPRel32Directive - if non-null, a directive that is used to emit a word
203    /// which should be relocated as a 32-bit GP-relative offset, e.g. .gpword
204    /// on Mips or .gprel32 on Alpha.
205    const char *GPRel32Directive;            // Defaults to NULL.
206
207    /// SunStyleELFSectionSwitchSyntax - This is true if this target uses "Sun
208    /// Style" syntax for section switching ("#alloc,#write" etc) instead of the
209    /// normal ELF syntax (,"a,w") in .section directives.
210    bool SunStyleELFSectionSwitchSyntax;     // Defaults to false.
211
212    /// UsesELFSectionDirectiveForBSS - This is true if this target uses ELF
213    /// '.section' directive before the '.bss' one. It's used for PPC/Linux
214    /// which doesn't support the '.bss' directive only.
215    bool UsesELFSectionDirectiveForBSS;      // Defaults to false.
216
217    /// HasMicrosoftFastStdCallMangling - True if this target uses microsoft
218    /// style mangling for functions with X86_StdCall/X86_FastCall calling
219    /// convention.
220    bool HasMicrosoftFastStdCallMangling;    // Defaults to false.
221
222    bool NeedsDwarfSectionOffsetDirective;
223
224    //===--- Alignment Information ----------------------------------------===//
225
226    /// AlignDirective - The directive used to emit round up to an alignment
227    /// boundary.
228    ///
229    const char *AlignDirective;              // Defaults to "\t.align\t"
230
231    /// AlignmentIsInBytes - If this is true (the default) then the asmprinter
232    /// emits ".align N" directives, where N is the number of bytes to align to.
233    /// Otherwise, it emits ".align log2(N)", e.g. 3 to align to an 8 byte
234    /// boundary.
235    bool AlignmentIsInBytes;                 // Defaults to true
236
237    /// TextAlignFillValue - If non-zero, this is used to fill the executable
238    /// space created as the result of a alignment directive.
239    unsigned TextAlignFillValue;             // Defaults to 0
240
241    //===--- Global Variable Emission Directives --------------------------===//
242
243    /// GlobalDirective - This is the directive used to declare a global entity.
244    ///
245    const char *GlobalDirective;             // Defaults to NULL.
246
247    /// HasSetDirective - True if the assembler supports the .set directive.
248    bool HasSetDirective;                    // Defaults to true.
249
250    /// HasAggressiveSymbolFolding - False if the assembler requires that we use
251    /// Lc = a - b
252    /// .long Lc
253    /// instead of
254    /// .long a - b
255    bool HasAggressiveSymbolFolding;           // Defaults to true.
256
257    /// COMMDirectiveAlignmentIsInBytes - True is .comm's and .lcomms optional
258    /// alignment is to be specified in bytes instead of log2(n).
259    bool COMMDirectiveAlignmentIsInBytes;    // Defaults to true;
260
261    /// LCOMMDirectiveAlignment - Describes if the .lcomm directive for the
262    /// target supports an alignment argument and how it is interpreted.
263    LCOMM::LCOMMType LCOMMDirectiveAlignmentType; // Defaults to NoAlignment.
264
265    /// HasDotTypeDotSizeDirective - True if the target has .type and .size
266    /// directives, this is true for most ELF targets.
267    bool HasDotTypeDotSizeDirective;         // Defaults to true.
268
269    /// HasSingleParameterDotFile - True if the target has a single parameter
270    /// .file directive, this is true for ELF targets.
271    bool HasSingleParameterDotFile;          // Defaults to true.
272
273    /// hasIdentDirective - True if the target has a .ident directive, this is
274    /// true for ELF targets.
275    bool HasIdentDirective;                  // Defaults to false.
276
277    /// HasNoDeadStrip - True if this target supports the MachO .no_dead_strip
278    /// directive.
279    bool HasNoDeadStrip;                     // Defaults to false.
280
281    /// WeakRefDirective - This directive, if non-null, is used to declare a
282    /// global as being a weak undefined symbol.
283    const char *WeakRefDirective;            // Defaults to NULL.
284
285    /// WeakDefDirective - This directive, if non-null, is used to declare a
286    /// global as being a weak defined symbol.
287    const char *WeakDefDirective;            // Defaults to NULL.
288
289    /// LinkOnceDirective - This directive, if non-null is used to declare a
290    /// global as being a weak defined symbol.  This is used on cygwin/mingw.
291    const char *LinkOnceDirective;           // Defaults to NULL.
292
293    /// HiddenVisibilityAttr - This attribute, if not MCSA_Invalid, is used to
294    /// declare a symbol as having hidden visibility.
295    MCSymbolAttr HiddenVisibilityAttr;       // Defaults to MCSA_Hidden.
296
297    /// HiddenDeclarationVisibilityAttr - This attribute, if not MCSA_Invalid,
298    /// is used to declare an undefined symbol as having hidden visibility.
299    MCSymbolAttr HiddenDeclarationVisibilityAttr;   // Defaults to MCSA_Hidden.
300
301
302    /// ProtectedVisibilityAttr - This attribute, if not MCSA_Invalid, is used
303    /// to declare a symbol as having protected visibility.
304    MCSymbolAttr ProtectedVisibilityAttr;    // Defaults to MCSA_Protected
305
306    //===--- Dwarf Emission Directives -----------------------------------===//
307
308    /// HasLEB128 - True if target asm supports leb128 directives.
309    bool HasLEB128;                          // Defaults to false.
310
311    /// SupportsDebugInformation - True if target supports emission of debugging
312    /// information.
313    bool SupportsDebugInformation;           // Defaults to false.
314
315    /// SupportsExceptionHandling - True if target supports exception handling.
316    ExceptionHandling::ExceptionsType ExceptionsType; // Defaults to None
317
318    /// DwarfUsesRelocationsAcrossSections - True if Dwarf2 output generally
319    /// uses relocations for references to other .debug_* sections.
320    bool DwarfUsesRelocationsAcrossSections;
321
322    /// DwarfRegNumForCFI - True if dwarf register numbers are printed
323    /// instead of symbolic register names in .cfi_* directives.
324    bool DwarfRegNumForCFI;  // Defaults to false;
325
326    //===--- Prologue State ----------------------------------------------===//
327
328    std::vector<MCCFIInstruction> InitialFrameState;
329
330  public:
331    explicit MCAsmInfo();
332    virtual ~MCAsmInfo();
333
334    // FIXME: move these methods to DwarfPrinter when the JIT stops using them.
335    static unsigned getSLEB128Size(int64_t Value);
336    static unsigned getULEB128Size(uint64_t Value);
337
338    /// getPointerSize - Get the pointer size in bytes.
339    unsigned getPointerSize() const {
340      return PointerSize;
341    }
342
343    /// getCalleeSaveStackSlotSize - Get the callee-saved register stack slot
344    /// size in bytes.
345    unsigned getCalleeSaveStackSlotSize() const {
346      return CalleeSaveStackSlotSize;
347    }
348
349    /// isLittleEndian - True if the target is little endian.
350    bool isLittleEndian() const {
351      return IsLittleEndian;
352    }
353
354    /// isStackGrowthDirectionUp - True if target stack grow up.
355    bool isStackGrowthDirectionUp() const {
356      return StackGrowsUp;
357    }
358
359    bool hasSubsectionsViaSymbols() const { return HasSubsectionsViaSymbols; }
360
361    // Data directive accessors.
362    //
363    const char *getData8bitsDirective() const {
364      return Data8bitsDirective;
365    }
366    const char *getData16bitsDirective() const {
367      return Data16bitsDirective;
368    }
369    const char *getData32bitsDirective() const {
370      return Data32bitsDirective;
371    }
372    const char *getData64bitsDirective() const {
373      return Data64bitsDirective;
374    }
375    const char *getGPRel64Directive() const { return GPRel64Directive; }
376    const char *getGPRel32Directive() const { return GPRel32Directive; }
377
378    /// getNonexecutableStackSection - Targets can implement this method to
379    /// specify a section to switch to if the translation unit doesn't have any
380    /// trampolines that require an executable stack.
381    virtual const MCSection *getNonexecutableStackSection(MCContext &Ctx) const{
382      return 0;
383    }
384
385    virtual const MCExpr *
386    getExprForPersonalitySymbol(const MCSymbol *Sym,
387                                unsigned Encoding,
388                                MCStreamer &Streamer) const;
389
390    const MCExpr *
391    getExprForFDESymbol(const MCSymbol *Sym,
392                        unsigned Encoding,
393                        MCStreamer &Streamer) const;
394
395    bool usesSunStyleELFSectionSwitchSyntax() const {
396      return SunStyleELFSectionSwitchSyntax;
397    }
398
399    bool usesELFSectionDirectiveForBSS() const {
400      return UsesELFSectionDirectiveForBSS;
401    }
402
403    bool hasMicrosoftFastStdCallMangling() const {
404      return HasMicrosoftFastStdCallMangling;
405    }
406
407    bool needsDwarfSectionOffsetDirective() const {
408      return NeedsDwarfSectionOffsetDirective;
409    }
410
411    // Accessors.
412    //
413    bool hasMachoZeroFillDirective() const { return HasMachoZeroFillDirective; }
414    bool hasMachoTBSSDirective() const { return HasMachoTBSSDirective; }
415    bool hasStaticCtorDtorReferenceInStaticMode() const {
416      return HasStaticCtorDtorReferenceInStaticMode;
417    }
418    bool getLinkerRequiresNonEmptyDwarfLines() const {
419      return LinkerRequiresNonEmptyDwarfLines;
420    }
421    unsigned getMaxInstLength() const {
422      return MaxInstLength;
423    }
424    unsigned getMinInstAlignment() const {
425      return MinInstAlignment;
426    }
427    bool getDollarIsPC() const {
428      return DollarIsPC;
429    }
430    const char *getSeparatorString() const {
431      return SeparatorString;
432    }
433    unsigned getCommentColumn() const {
434      return CommentColumn;
435    }
436    const char *getCommentString() const {
437      return CommentString;
438    }
439    const char *getLabelSuffix() const {
440      return LabelSuffix;
441    }
442
443    const char *getDebugLabelSuffix() const {
444      return DebugLabelSuffix;
445    }
446
447    const char *getGlobalPrefix() const {
448      return GlobalPrefix;
449    }
450    const char *getPrivateGlobalPrefix() const {
451      return PrivateGlobalPrefix;
452    }
453    const char *getLinkerPrivateGlobalPrefix() const {
454      return LinkerPrivateGlobalPrefix;
455    }
456    const char *getInlineAsmStart() const {
457      return InlineAsmStart;
458    }
459    const char *getInlineAsmEnd() const {
460      return InlineAsmEnd;
461    }
462    const char *getCode16Directive() const {
463      return Code16Directive;
464    }
465    const char *getCode32Directive() const {
466      return Code32Directive;
467    }
468    const char *getCode64Directive() const {
469      return Code64Directive;
470    }
471    unsigned getAssemblerDialect() const {
472      return AssemblerDialect;
473    }
474    bool doesAllowQuotesInName() const {
475      return AllowQuotesInName;
476    }
477    bool doesAllowNameToStartWithDigit() const {
478      return AllowNameToStartWithDigit;
479    }
480    bool doesAllowPeriodsInName() const {
481      return AllowPeriodsInName;
482    }
483    bool doesAllowAtInName() const {
484      return AllowAtInName;
485    }
486    bool doesAllowUTF8() const {
487      return AllowUTF8;
488    }
489    bool doesSupportDataRegionDirectives() const {
490      return UseDataRegionDirectives;
491    }
492    const char *getZeroDirective() const {
493      return ZeroDirective;
494    }
495    const char *getAsciiDirective() const {
496      return AsciiDirective;
497    }
498    const char *getAscizDirective() const {
499      return AscizDirective;
500    }
501    const char *getAlignDirective() const {
502      return AlignDirective;
503    }
504    bool getAlignmentIsInBytes() const {
505      return AlignmentIsInBytes;
506    }
507    unsigned getTextAlignFillValue() const {
508      return TextAlignFillValue;
509    }
510    const char *getGlobalDirective() const {
511      return GlobalDirective;
512    }
513    bool hasSetDirective() const { return HasSetDirective; }
514    bool hasAggressiveSymbolFolding() const {
515      return HasAggressiveSymbolFolding;
516    }
517    bool getCOMMDirectiveAlignmentIsInBytes() const {
518      return COMMDirectiveAlignmentIsInBytes;
519    }
520    LCOMM::LCOMMType getLCOMMDirectiveAlignmentType() const {
521      return LCOMMDirectiveAlignmentType;
522    }
523    bool hasDotTypeDotSizeDirective() const {return HasDotTypeDotSizeDirective;}
524    bool hasSingleParameterDotFile() const { return HasSingleParameterDotFile; }
525    bool hasIdentDirective() const { return HasIdentDirective; }
526    bool hasNoDeadStrip() const { return HasNoDeadStrip; }
527    const char *getWeakRefDirective() const { return WeakRefDirective; }
528    const char *getWeakDefDirective() const { return WeakDefDirective; }
529    const char *getLinkOnceDirective() const { return LinkOnceDirective; }
530
531    MCSymbolAttr getHiddenVisibilityAttr() const { return HiddenVisibilityAttr;}
532    MCSymbolAttr getHiddenDeclarationVisibilityAttr() const {
533      return HiddenDeclarationVisibilityAttr;
534    }
535    MCSymbolAttr getProtectedVisibilityAttr() const {
536      return ProtectedVisibilityAttr;
537    }
538    bool hasLEB128() const {
539      return HasLEB128;
540    }
541    bool doesSupportDebugInformation() const {
542      return SupportsDebugInformation;
543    }
544    bool doesSupportExceptionHandling() const {
545      return ExceptionsType != ExceptionHandling::None;
546    }
547    ExceptionHandling::ExceptionsType getExceptionHandlingType() const {
548      return ExceptionsType;
549    }
550    bool isExceptionHandlingDwarf() const {
551      return
552        (ExceptionsType == ExceptionHandling::DwarfCFI ||
553         ExceptionsType == ExceptionHandling::ARM ||
554         ExceptionsType == ExceptionHandling::Win64);
555    }
556    bool doesDwarfUseRelocationsAcrossSections() const {
557      return DwarfUsesRelocationsAcrossSections;
558    }
559    bool useDwarfRegNumForCFI() const {
560      return DwarfRegNumForCFI;
561    }
562
563    void addInitialFrameState(const MCCFIInstruction &Inst) {
564      InitialFrameState.push_back(Inst);
565    }
566
567    const std::vector<MCCFIInstruction> &getInitialFrameState() const {
568      return InitialFrameState;
569    }
570  };
571}
572
573#endif
574