MCAsmInfo.h revision 746cb670c3cd4f79b288d56d8e9f195685a5381a 
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  namespace Structors {
40    enum OutputOrder { None, PriorityOrder, ReversePriorityOrder };
41  }
42
43  /// MCAsmInfo - This class is intended to be used as a base class for asm
44  /// properties and features specific to the target.
45  class MCAsmInfo {
46  protected:
47    //===------------------------------------------------------------------===//
48    // Properties to be set by the target writer, used to configure asm printer.
49    //
50
51    /// PointerSize - Pointer size in bytes.
52    ///               Default is 4.
53    unsigned PointerSize;
54
55    /// IsLittleEndian - True if target is little endian.
56    ///                  Default is true.
57    bool IsLittleEndian;
58
59    /// StackGrowsUp - True if target stack grow up.
60    ///                Default is false.
61    bool StackGrowsUp;
62
63    /// HasSubsectionsViaSymbols - True if this target has the MachO
64    /// .subsections_via_symbols directive.
65    bool HasSubsectionsViaSymbols;           // Default is false.
66
67    /// HasMachoZeroFillDirective - True if this is a MachO target that supports
68    /// the macho-specific .zerofill directive for emitting BSS Symbols.
69    bool HasMachoZeroFillDirective;               // Default is false.
70
71    /// HasMachoTBSSDirective - True if this is a MachO target that supports
72    /// the macho-specific .tbss directive for emitting thread local BSS Symbols
73    bool HasMachoTBSSDirective;                 // Default is false.
74
75    /// StructorOutputOrder - Whether the static ctor/dtor list should be output
76    /// in no particular order, in order of increasing priority or the reverse:
77    /// in order of decreasing priority (the default).
78    Structors::OutputOrder StructorOutputOrder; // Default is reverse order.
79
80    /// HasStaticCtorDtorReferenceInStaticMode - True if the compiler should
81    /// emit a ".reference .constructors_used" or ".reference .destructors_used"
82    /// directive after the a static ctor/dtor list.  This directive is only
83    /// emitted in Static relocation model.
84    bool HasStaticCtorDtorReferenceInStaticMode;  // Default is false.
85
86    /// LinkerRequiresNonEmptyDwarfLines - True if the linker has a bug and
87    /// requires that the debug_line section be of a minimum size. In practice
88    /// such a linker requires a non empty line sequence if a file is present.
89    bool LinkerRequiresNonEmptyDwarfLines; // Default to false.
90
91    /// MaxInstLength - This is the maximum possible length of an instruction,
92    /// which is needed to compute the size of an inline asm.
93    unsigned MaxInstLength;                  // Defaults to 4.
94
95    /// PCSymbol - The symbol used to represent the current PC.  Used in PC
96    /// relative expressions.
97    const char *PCSymbol;                    // Defaults to "$".
98
99    /// SeparatorString - This string, if specified, is used to separate
100    /// instructions from each other when on the same line.
101    const char *SeparatorString;             // Defaults to ';'
102
103    /// CommentColumn - This indicates the comment num (zero-based) at
104    /// which asm comments should be printed.
105    unsigned CommentColumn;                  // Defaults to 40
106
107    /// CommentString - This indicates the comment character used by the
108    /// assembler.
109    const char *CommentString;               // Defaults to "#"
110
111    /// LabelSuffix - This is appended to emitted labels.
112    const char *LabelSuffix;                 // Defaults to ":"
113
114    /// GlobalPrefix - If this is set to a non-empty string, it is prepended
115    /// onto all global symbols.  This is often used for "_" or ".".
116    const char *GlobalPrefix;                // Defaults to ""
117
118    /// PrivateGlobalPrefix - This prefix is used for globals like constant
119    /// pool entries that are completely private to the .s file and should not
120    /// have names in the .o file.  This is often "." or "L".
121    const char *PrivateGlobalPrefix;         // Defaults to "."
122
123    /// LinkerPrivateGlobalPrefix - This prefix is used for symbols that should
124    /// be passed through the assembler but be removed by the linker.  This
125    /// is "l" on Darwin, currently used for some ObjC metadata.
126    const char *LinkerPrivateGlobalPrefix;   // Defaults to ""
127
128    /// InlineAsmStart/End - If these are nonempty, they contain a directive to
129    /// emit before and after an inline assembly statement.
130    const char *InlineAsmStart;              // Defaults to "#APP\n"
131    const char *InlineAsmEnd;                // Defaults to "#NO_APP\n"
132
133    /// Code16Directive, Code32Directive, Code64Directive - These are assembly
134    /// directives that tells the assembler to interpret the following
135    /// instructions differently.
136    const char *Code16Directive;             // Defaults to ".code16"
137    const char *Code32Directive;             // Defaults to ".code32"
138    const char *Code64Directive;             // Defaults to ".code64"
139
140    /// AssemblerDialect - Which dialect of an assembler variant to use.
141    unsigned AssemblerDialect;               // Defaults to 0
142
143    /// AllowQuotesInName - This is true if the assembler allows for complex
144    /// symbol names to be surrounded in quotes.  This defaults to false.
145    bool AllowQuotesInName;
146
147    /// AllowNameToStartWithDigit - This is true if the assembler allows symbol
148    /// names to start with a digit (e.g., "0x0021").  This defaults to false.
149    bool AllowNameToStartWithDigit;
150
151    /// AllowPeriodsInName - This is true if the assembler allows periods in
152    /// symbol names.  This defaults to true.
153    bool AllowPeriodsInName;
154
155    //===--- Data Emission Directives -------------------------------------===//
156
157    /// ZeroDirective - this should be set to the directive used to get some
158    /// number of zero bytes emitted to the current section.  Common cases are
159    /// "\t.zero\t" and "\t.space\t".  If this is set to null, the
160    /// Data*bitsDirective's will be used to emit zero bytes.
161    const char *ZeroDirective;               // Defaults to "\t.zero\t"
162
163    /// AsciiDirective - This directive allows emission of an ascii string with
164    /// the standard C escape characters embedded into it.
165    const char *AsciiDirective;              // Defaults to "\t.ascii\t"
166
167    /// AscizDirective - If not null, this allows for special handling of
168    /// zero terminated strings on this target.  This is commonly supported as
169    /// ".asciz".  If a target doesn't support this, it can be set to null.
170    const char *AscizDirective;              // Defaults to "\t.asciz\t"
171
172    /// DataDirectives - These directives are used to output some unit of
173    /// integer data to the current section.  If a data directive is set to
174    /// null, smaller data directives will be used to emit the large sizes.
175    const char *Data8bitsDirective;          // Defaults to "\t.byte\t"
176    const char *Data16bitsDirective;         // Defaults to "\t.short\t"
177    const char *Data32bitsDirective;         // Defaults to "\t.long\t"
178    const char *Data64bitsDirective;         // Defaults to "\t.quad\t"
179
180    /// [Data|Code]Begin - These magic labels are used to marked a region as
181    /// data or code, and are used to provide additional information for
182    /// correct disassembly on targets that like to mix data and code within
183    /// a segment.  These labels will be implicitly suffixed by the streamer
184    /// to give them unique names.
185    const char *DataBegin;                   // Defaults to "$d."
186    const char *CodeBegin;                   // Defaults to "$a."
187    const char *JT8Begin;                    // Defaults to "$a."
188    const char *JT16Begin;                   // Defaults to "$a."
189    const char *JT32Begin;                   // Defaults to "$a."
190    bool SupportsDataRegions;
191
192    /// GPRel32Directive - if non-null, a directive that is used to emit a word
193    /// which should be relocated as a 32-bit GP-relative offset, e.g. .gpword
194    /// on Mips or .gprel32 on Alpha.
195    const char *GPRel32Directive;            // Defaults to NULL.
196
197    /// getDataASDirective - Return the directive that should be used to emit
198    /// data of the specified size to the specified numeric address space.
199    virtual const char *getDataASDirective(unsigned Size, unsigned AS) const {
200      assert(AS != 0 && "Don't know the directives for default addr space");
201      return 0;
202    }
203
204    /// SunStyleELFSectionSwitchSyntax - This is true if this target uses "Sun
205    /// Style" syntax for section switching ("#alloc,#write" etc) instead of the
206    /// normal ELF syntax (,"a,w") in .section directives.
207    bool SunStyleELFSectionSwitchSyntax;     // Defaults to false.
208
209    /// UsesELFSectionDirectiveForBSS - This is true if this target uses ELF
210    /// '.section' directive before the '.bss' one. It's used for PPC/Linux
211    /// which doesn't support the '.bss' directive only.
212    bool UsesELFSectionDirectiveForBSS;      // Defaults to false.
213
214    /// HasMicrosoftFastStdCallMangling - True if this target uses microsoft
215    /// style mangling for functions with X86_StdCall/X86_FastCall calling
216    /// convention.
217    bool HasMicrosoftFastStdCallMangling;    // Defaults to false.
218
219    //===--- Alignment Information ----------------------------------------===//
220
221    /// AlignDirective - The directive used to emit round up to an alignment
222    /// boundary.
223    ///
224    const char *AlignDirective;              // Defaults to "\t.align\t"
225
226    /// AlignmentIsInBytes - If this is true (the default) then the asmprinter
227    /// emits ".align N" directives, where N is the number of bytes to align to.
228    /// Otherwise, it emits ".align log2(N)", e.g. 3 to align to an 8 byte
229    /// boundary.
230    bool AlignmentIsInBytes;                 // Defaults to true
231
232    /// TextAlignFillValue - If non-zero, this is used to fill the executable
233    /// space created as the result of a alignment directive.
234    unsigned TextAlignFillValue;             // Defaults to 0
235
236    //===--- Global Variable Emission Directives --------------------------===//
237
238    /// GlobalDirective - This is the directive used to declare a global entity.
239    ///
240    const char *GlobalDirective;             // Defaults to NULL.
241
242    /// ExternDirective - This is the directive used to declare external
243    /// globals.
244    ///
245    const char *ExternDirective;             // 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    /// LCOMMDirectiveType - Describes if the target supports the .lcomm
258    /// directive and whether it has an alignment parameter.
259    LCOMM::LCOMMType LCOMMDirectiveType;     // Defaults to LCOMM::None.
260
261    /// COMMDirectiveAlignmentIsInBytes - True is COMMDirective's optional
262    /// alignment is to be specified in bytes instead of log2(n).
263    bool COMMDirectiveAlignmentIsInBytes;    // Defaults to true;
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    /// HasNoDeadStrip - True if this target supports the MachO .no_dead_strip
274    /// directive.
275    bool HasNoDeadStrip;                     // Defaults to false.
276
277    /// HasSymbolResolver - True if this target supports the MachO
278    /// .symbol_resolver directive.
279    bool HasSymbolResolver;                     // 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    /// DwarfUsesInlineInfoSection - True if DwarfDebugInlineSection is used to
319    /// encode inline subroutine information.
320    bool DwarfUsesInlineInfoSection;         // Defaults to false.
321
322    /// DwarfSectionOffsetDirective - Special section offset directive.
323    const char* DwarfSectionOffsetDirective; // Defaults to NULL
324
325    /// DwarfRequiresRelocationForSectionOffset - True if we need to produce a
326    /// relocation when we want a section offset in dwarf.
327    bool DwarfRequiresRelocationForSectionOffset;  // Defaults to true;
328
329    /// DwarfUsesLabelOffsetDifference - True if Dwarf2 output can
330    /// use EmitLabelOffsetDifference.
331    bool DwarfUsesLabelOffsetForRanges;
332
333    /// DwarfRegNumForCFI - True if dwarf register numbers are printed
334    /// instead of symbolic register names in .cfi_* directives.
335    bool DwarfRegNumForCFI;  // Defaults to false;
336
337    //===--- CBE Asm Translation Table -----------------------------------===//
338
339    const char *const *AsmTransCBE;          // Defaults to empty
340
341    //===--- Prologue State ----------------------------------------------===//
342
343    std::vector<MachineMove> InitialFrameState;
344
345  public:
346    explicit MCAsmInfo();
347    virtual ~MCAsmInfo();
348
349    // FIXME: move these methods to DwarfPrinter when the JIT stops using them.
350    static unsigned getSLEB128Size(int Value);
351    static unsigned getULEB128Size(unsigned Value);
352
353    /// getPointerSize - Get the pointer size in bytes.
354    unsigned getPointerSize() const {
355      return PointerSize;
356    }
357
358    /// islittleendian - True if the target is little endian.
359    bool isLittleEndian() const {
360      return IsLittleEndian;
361    }
362
363    /// isStackGrowthDirectionUp - True if target stack grow up.
364    bool isStackGrowthDirectionUp() const {
365      return StackGrowsUp;
366    }
367
368    bool hasSubsectionsViaSymbols() const { return HasSubsectionsViaSymbols; }
369
370    // Data directive accessors.
371    //
372    const char *getData8bitsDirective(unsigned AS = 0) const {
373      return AS == 0 ? Data8bitsDirective : getDataASDirective(8, AS);
374    }
375    const char *getData16bitsDirective(unsigned AS = 0) const {
376      return AS == 0 ? Data16bitsDirective : getDataASDirective(16, AS);
377    }
378    const char *getData32bitsDirective(unsigned AS = 0) const {
379      return AS == 0 ? Data32bitsDirective : getDataASDirective(32, AS);
380    }
381    const char *getData64bitsDirective(unsigned AS = 0) const {
382      return AS == 0 ? Data64bitsDirective : getDataASDirective(64, AS);
383    }
384    const char *getGPRel32Directive() const { return GPRel32Directive; }
385
386    /// [Code|Data]Begin label name accessors.
387    const char *getCodeBeginLabelName() const { return CodeBegin; }
388    const char *getDataBeginLabelName() const { return DataBegin; }
389    const char *getJumpTable8BeginLabelName() const { return JT8Begin; }
390    const char *getJumpTable16BeginLabelName() const { return JT16Begin; }
391    const char *getJumpTable32BeginLabelName() const { return JT32Begin; }
392    bool getSupportsDataRegions() const { return SupportsDataRegions; }
393
394    /// getNonexecutableStackSection - Targets can implement this method to
395    /// specify a section to switch to if the translation unit doesn't have any
396    /// trampolines that require an executable stack.
397    virtual const MCSection *getNonexecutableStackSection(MCContext &Ctx) const{
398      return 0;
399    }
400
401    virtual const MCExpr *
402    getExprForPersonalitySymbol(const MCSymbol *Sym,
403                                unsigned Encoding,
404                                MCStreamer &Streamer) const;
405
406    const MCExpr *
407    getExprForFDESymbol(const MCSymbol *Sym,
408                        unsigned Encoding,
409                        MCStreamer &Streamer) const;
410
411    bool usesSunStyleELFSectionSwitchSyntax() const {
412      return SunStyleELFSectionSwitchSyntax;
413    }
414
415    bool usesELFSectionDirectiveForBSS() const {
416      return UsesELFSectionDirectiveForBSS;
417    }
418
419    bool hasMicrosoftFastStdCallMangling() const {
420      return HasMicrosoftFastStdCallMangling;
421    }
422
423    // Accessors.
424    //
425    bool hasMachoZeroFillDirective() const { return HasMachoZeroFillDirective; }
426    bool hasMachoTBSSDirective() const { return HasMachoTBSSDirective; }
427    Structors::OutputOrder getStructorOutputOrder() const {
428      return StructorOutputOrder;
429    }
430    bool hasStaticCtorDtorReferenceInStaticMode() const {
431      return HasStaticCtorDtorReferenceInStaticMode;
432    }
433    bool getLinkerRequiresNonEmptyDwarfLines() const {
434      return LinkerRequiresNonEmptyDwarfLines;
435    }
436    unsigned getMaxInstLength() const {
437      return MaxInstLength;
438    }
439    const char *getPCSymbol() const {
440      return PCSymbol;
441    }
442    const char *getSeparatorString() const {
443      return SeparatorString;
444    }
445    unsigned getCommentColumn() const {
446      return CommentColumn;
447    }
448    const char *getCommentString() const {
449      return CommentString;
450    }
451    const char *getLabelSuffix() const {
452      return LabelSuffix;
453    }
454    const char *getGlobalPrefix() const {
455      return GlobalPrefix;
456    }
457    const char *getPrivateGlobalPrefix() const {
458      return PrivateGlobalPrefix;
459    }
460    const char *getLinkerPrivateGlobalPrefix() const {
461      return LinkerPrivateGlobalPrefix;
462    }
463    const char *getInlineAsmStart() const {
464      return InlineAsmStart;
465    }
466    const char *getInlineAsmEnd() const {
467      return InlineAsmEnd;
468    }
469    const char *getCode16Directive() const {
470      return Code16Directive;
471    }
472    const char *getCode32Directive() const {
473      return Code32Directive;
474    }
475    const char *getCode64Directive() const {
476      return Code64Directive;
477    }
478    unsigned getAssemblerDialect() const {
479      return AssemblerDialect;
480    }
481    bool doesAllowQuotesInName() const {
482      return AllowQuotesInName;
483    }
484    bool doesAllowNameToStartWithDigit() const {
485      return AllowNameToStartWithDigit;
486    }
487    bool doesAllowPeriodsInName() const {
488      return AllowPeriodsInName;
489    }
490    const char *getZeroDirective() const {
491      return ZeroDirective;
492    }
493    const char *getAsciiDirective() const {
494      return AsciiDirective;
495    }
496    const char *getAscizDirective() const {
497      return AscizDirective;
498    }
499    const char *getAlignDirective() const {
500      return AlignDirective;
501    }
502    bool getAlignmentIsInBytes() const {
503      return AlignmentIsInBytes;
504    }
505    unsigned getTextAlignFillValue() const {
506      return TextAlignFillValue;
507    }
508    const char *getGlobalDirective() const {
509      return GlobalDirective;
510    }
511    const char *getExternDirective() const {
512      return ExternDirective;
513    }
514    bool hasSetDirective() const { return HasSetDirective; }
515    bool hasAggressiveSymbolFolding() const {
516      return HasAggressiveSymbolFolding;
517    }
518    LCOMM::LCOMMType getLCOMMDirectiveType() const {
519      return LCOMMDirectiveType;
520    }
521    bool hasDotTypeDotSizeDirective() const {return HasDotTypeDotSizeDirective;}
522    bool getCOMMDirectiveAlignmentIsInBytes() const {
523      return COMMDirectiveAlignmentIsInBytes;
524    }
525    bool hasSingleParameterDotFile() const { return HasSingleParameterDotFile; }
526    bool hasNoDeadStrip() const { return HasNoDeadStrip; }
527    bool hasSymbolResolver() const { return HasSymbolResolver; }
528    const char *getWeakRefDirective() const { return WeakRefDirective; }
529    const char *getWeakDefDirective() const { return WeakDefDirective; }
530    const char *getLinkOnceDirective() const { return LinkOnceDirective; }
531
532    MCSymbolAttr getHiddenVisibilityAttr() const { return HiddenVisibilityAttr;}
533    MCSymbolAttr getHiddenDeclarationVisibilityAttr() const {
534      return HiddenDeclarationVisibilityAttr;
535    }
536    MCSymbolAttr getProtectedVisibilityAttr() const {
537      return ProtectedVisibilityAttr;
538    }
539    bool hasLEB128() const {
540      return HasLEB128;
541    }
542    bool doesSupportDebugInformation() const {
543      return SupportsDebugInformation;
544    }
545    bool doesSupportExceptionHandling() const {
546      return ExceptionsType != ExceptionHandling::None;
547    }
548    ExceptionHandling::ExceptionsType getExceptionHandlingType() const {
549      return ExceptionsType;
550    }
551    bool isExceptionHandlingDwarf() const {
552      return
553        (ExceptionsType == ExceptionHandling::DwarfCFI ||
554         ExceptionsType == ExceptionHandling::ARM ||
555         ExceptionsType == ExceptionHandling::Win64);
556    }
557    bool doesDwarfUsesInlineInfoSection() const {
558      return DwarfUsesInlineInfoSection;
559    }
560    const char *getDwarfSectionOffsetDirective() const {
561      return DwarfSectionOffsetDirective;
562    }
563    bool doesDwarfRequireRelocationForSectionOffset() const {
564      return DwarfRequiresRelocationForSectionOffset;
565    }
566    bool doesDwarfUsesLabelOffsetForRanges() const {
567      return DwarfUsesLabelOffsetForRanges;
568    }
569    bool useDwarfRegNumForCFI() const {
570      return DwarfRegNumForCFI;
571    }
572    const char *const *getAsmCBE() const {
573      return AsmTransCBE;
574    }
575
576    void addInitialFrameState(MCSymbol *label, const MachineLocation &D,
577                              const MachineLocation &S) {
578      InitialFrameState.push_back(MachineMove(label, D, S));
579    }
580    const std::vector<MachineMove> &getInitialFrameState() const {
581      return InitialFrameState;
582    }
583  };
584}
585
586#endif
587