MCAsmInfo.h revision 9a0e12a6ed7db1bf49e4676932427e91ae4eb9be 
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/MachineLocation.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 { NoAlignment, ByteAlignment, Log2Alignment };
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    /// CalleeSaveStackSlotSize - Size of the stack slot reserved for
52    ///                           callee-saved registers, in bytes.
53    ///                           Default is same as pointer size.
54    unsigned CalleeSaveStackSlotSize;
55
56    /// IsLittleEndian - True if target is little endian.
57    ///                  Default is true.
58    bool IsLittleEndian;
59
60    /// StackGrowsUp - True if target stack grow up.
61    ///                Default is false.
62    bool StackGrowsUp;
63
64    /// HasSubsectionsViaSymbols - True if this target has the MachO
65    /// .subsections_via_symbols directive.
66    bool HasSubsectionsViaSymbols;           // Default is false.
67
68    /// HasMachoZeroFillDirective - True if this is a MachO target that supports
69    /// the macho-specific .zerofill directive for emitting BSS Symbols.
70    bool HasMachoZeroFillDirective;               // Default is false.
71
72    /// HasMachoTBSSDirective - True if this is a MachO target that supports
73    /// the macho-specific .tbss directive for emitting thread local BSS Symbols
74    bool HasMachoTBSSDirective;                 // Default is false.
75
76    /// HasStaticCtorDtorReferenceInStaticMode - True if the compiler should
77    /// emit a ".reference .constructors_used" or ".reference .destructors_used"
78    /// directive after the a static ctor/dtor list.  This directive is only
79    /// emitted in Static relocation model.
80    bool HasStaticCtorDtorReferenceInStaticMode;  // Default is false.
81
82    /// LinkerRequiresNonEmptyDwarfLines - True if the linker has a bug and
83    /// requires that the debug_line section be of a minimum size. In practice
84    /// such a linker requires a non empty line sequence if a file is present.
85    bool LinkerRequiresNonEmptyDwarfLines; // Default to false.
86
87    /// MaxInstLength - This is the maximum possible length of an instruction,
88    /// which is needed to compute the size of an inline asm.
89    unsigned MaxInstLength;                  // Defaults to 4.
90
91    /// PCSymbol - The symbol used to represent the current PC.  Used in PC
92    /// relative expressions.
93    const char *PCSymbol;                    // Defaults to "$".
94
95    /// SeparatorString - This string, if specified, is used to separate
96    /// instructions from each other when on the same line.
97    const char *SeparatorString;             // Defaults to ';'
98
99    /// CommentColumn - This indicates the comment num (zero-based) at
100    /// which asm comments should be printed.
101    unsigned CommentColumn;                  // Defaults to 40
102
103    /// CommentString - This indicates the comment character used by the
104    /// assembler.
105    const char *CommentString;               // Defaults to "#"
106
107    /// LabelSuffix - This is appended to emitted labels.
108    const char *LabelSuffix;                 // Defaults to ":"
109
110    /// LabelSuffix - This is appended to emitted labels.
111    const char *DebugLabelSuffix;                 // Defaults to ":"
112
113    /// GlobalPrefix - If this is set to a non-empty string, it is prepended
114    /// onto all global symbols.  This is often used for "_" or ".".
115    const char *GlobalPrefix;                // Defaults to ""
116
117    /// PrivateGlobalPrefix - This prefix is used for globals like constant
118    /// pool entries that are completely private to the .s file and should not
119    /// have names in the .o file.  This is often "." or "L".
120    const char *PrivateGlobalPrefix;         // Defaults to "."
121
122    /// LinkerPrivateGlobalPrefix - This prefix is used for symbols that should
123    /// be passed through the assembler but be removed by the linker.  This
124    /// is "l" on Darwin, currently used for some ObjC metadata.
125    const char *LinkerPrivateGlobalPrefix;   // Defaults to ""
126
127    /// InlineAsmStart/End - If these are nonempty, they contain a directive to
128    /// emit before and after an inline assembly statement.
129    const char *InlineAsmStart;              // Defaults to "#APP\n"
130    const char *InlineAsmEnd;                // Defaults to "#NO_APP\n"
131
132    /// Code16Directive, Code32Directive, Code64Directive - These are assembly
133    /// directives that tells the assembler to interpret the following
134    /// instructions differently.
135    const char *Code16Directive;             // Defaults to ".code16"
136    const char *Code32Directive;             // Defaults to ".code32"
137    const char *Code64Directive;             // Defaults to ".code64"
138
139    /// AssemblerDialect - Which dialect of an assembler variant to use.
140    unsigned AssemblerDialect;               // Defaults to 0
141
142    /// AllowQuotesInName - This is true if the assembler allows for complex
143    /// symbol names to be surrounded in quotes.  This defaults to false.
144    bool AllowQuotesInName;
145
146    /// AllowNameToStartWithDigit - This is true if the assembler allows symbol
147    /// names to start with a digit (e.g., "0x0021").  This defaults to false.
148    bool AllowNameToStartWithDigit;
149
150    /// AllowPeriodsInName - This is true if the assembler allows periods in
151    /// symbol names.  This defaults to true.
152    bool AllowPeriodsInName;
153
154    /// AllowUTF8 - This is true if the assembler accepts UTF-8 input.
155    // FIXME: Make this a more general encoding setting?
156    bool AllowUTF8;
157
158    /// UseDataRegionDirectives - This is true if data region markers should
159    /// be printed as ".data_region/.end_data_region" directives. If false,
160    /// use "$d/$a" labels instead.
161    bool UseDataRegionDirectives;
162
163    //===--- Data Emission Directives -------------------------------------===//
164
165    /// ZeroDirective - this should be set to the directive used to get some
166    /// number of zero bytes emitted to the current section.  Common cases are
167    /// "\t.zero\t" and "\t.space\t".  If this is set to null, the
168    /// Data*bitsDirective's will be used to emit zero bytes.
169    const char *ZeroDirective;               // Defaults to "\t.zero\t"
170
171    /// AsciiDirective - This directive allows emission of an ascii string with
172    /// the standard C escape characters embedded into it.
173    const char *AsciiDirective;              // Defaults to "\t.ascii\t"
174
175    /// AscizDirective - If not null, this allows for special handling of
176    /// zero terminated strings on this target.  This is commonly supported as
177    /// ".asciz".  If a target doesn't support this, it can be set to null.
178    const char *AscizDirective;              // Defaults to "\t.asciz\t"
179
180    /// DataDirectives - These directives are used to output some unit of
181    /// integer data to the current section.  If a data directive is set to
182    /// null, smaller data directives will be used to emit the large sizes.
183    const char *Data8bitsDirective;          // Defaults to "\t.byte\t"
184    const char *Data16bitsDirective;         // Defaults to "\t.short\t"
185    const char *Data32bitsDirective;         // Defaults to "\t.long\t"
186    const char *Data64bitsDirective;         // Defaults to "\t.quad\t"
187
188    /// GPRel64Directive - if non-null, a directive that is used to emit a word
189    /// which should be relocated as a 64-bit GP-relative offset, e.g. .gpdword
190    /// on Mips.
191    const char *GPRel64Directive;            // Defaults to NULL.
192
193    /// GPRel32Directive - if non-null, a directive that is used to emit a word
194    /// which should be relocated as a 32-bit GP-relative offset, e.g. .gpword
195    /// on Mips or .gprel32 on Alpha.
196    const char *GPRel32Directive;            // Defaults to NULL.
197
198    /// getDataASDirective - Return the directive that should be used to emit
199    /// data of the specified size to the specified numeric address space.
200    virtual const char *getDataASDirective(unsigned Size, unsigned AS) const {
201      assert(AS != 0 && "Don't know the directives for default addr space");
202      return 0;
203    }
204
205    /// SunStyleELFSectionSwitchSyntax - This is true if this target uses "Sun
206    /// Style" syntax for section switching ("#alloc,#write" etc) instead of the
207    /// normal ELF syntax (,"a,w") in .section directives.
208    bool SunStyleELFSectionSwitchSyntax;     // Defaults to false.
209
210    /// UsesELFSectionDirectiveForBSS - This is true if this target uses ELF
211    /// '.section' directive before the '.bss' one. It's used for PPC/Linux
212    /// which doesn't support the '.bss' directive only.
213    bool UsesELFSectionDirectiveForBSS;      // Defaults to false.
214
215    /// HasMicrosoftFastStdCallMangling - True if this target uses microsoft
216    /// style mangling for functions with X86_StdCall/X86_FastCall calling
217    /// convention.
218    bool HasMicrosoftFastStdCallMangling;    // Defaults to false.
219
220    bool NeedsDwarfSectionOffsetDirective;
221
222    //===--- Alignment Information ----------------------------------------===//
223
224    /// AlignDirective - The directive used to emit round up to an alignment
225    /// boundary.
226    ///
227    const char *AlignDirective;              // Defaults to "\t.align\t"
228
229    /// AlignmentIsInBytes - If this is true (the default) then the asmprinter
230    /// emits ".align N" directives, where N is the number of bytes to align to.
231    /// Otherwise, it emits ".align log2(N)", e.g. 3 to align to an 8 byte
232    /// boundary.
233    bool AlignmentIsInBytes;                 // Defaults to true
234
235    /// TextAlignFillValue - If non-zero, this is used to fill the executable
236    /// space created as the result of a alignment directive.
237    unsigned TextAlignFillValue;             // Defaults to 0
238
239    //===--- Global Variable Emission Directives --------------------------===//
240
241    /// GlobalDirective - This is the directive used to declare a global entity.
242    ///
243    const char *GlobalDirective;             // Defaults to NULL.
244
245    /// ExternDirective - This is the directive used to declare external
246    /// globals.
247    ///
248    const char *ExternDirective;             // Defaults to NULL.
249
250    /// HasSetDirective - True if the assembler supports the .set directive.
251    bool HasSetDirective;                    // Defaults to true.
252
253    /// HasAggressiveSymbolFolding - False if the assembler requires that we use
254    /// Lc = a - b
255    /// .long Lc
256    /// instead of
257    /// .long a - b
258    bool HasAggressiveSymbolFolding;           // Defaults to true.
259
260    /// COMMDirectiveAlignmentIsInBytes - True is .comm's and .lcomms optional
261    /// alignment is to be specified in bytes instead of log2(n).
262    bool COMMDirectiveAlignmentIsInBytes;    // Defaults to true;
263
264    /// LCOMMDirectiveAlignment - Describes if the .lcomm directive for the
265    /// target supports an alignment argument and how it is interpreted.
266    LCOMM::LCOMMType LCOMMDirectiveAlignmentType; // Defaults to NoAlignment.
267
268    /// HasDotTypeDotSizeDirective - True if the target has .type and .size
269    /// directives, this is true for most ELF targets.
270    bool HasDotTypeDotSizeDirective;         // Defaults to true.
271
272    /// HasSingleParameterDotFile - True if the target has a single parameter
273    /// .file directive, this is true for ELF targets.
274    bool HasSingleParameterDotFile;          // Defaults to true.
275
276    /// HasNoDeadStrip - True if this target supports the MachO .no_dead_strip
277    /// directive.
278    bool HasNoDeadStrip;                     // Defaults to false.
279
280    /// HasSymbolResolver - True if this target supports the MachO
281    /// .symbol_resolver directive.
282    bool HasSymbolResolver;                     // Defaults to false.
283
284    /// WeakRefDirective - This directive, if non-null, is used to declare a
285    /// global as being a weak undefined symbol.
286    const char *WeakRefDirective;            // Defaults to NULL.
287
288    /// WeakDefDirective - This directive, if non-null, is used to declare a
289    /// global as being a weak defined symbol.
290    const char *WeakDefDirective;            // Defaults to NULL.
291
292    /// LinkOnceDirective - This directive, if non-null is used to declare a
293    /// global as being a weak defined symbol.  This is used on cygwin/mingw.
294    const char *LinkOnceDirective;           // Defaults to NULL.
295
296    /// HiddenVisibilityAttr - This attribute, if not MCSA_Invalid, is used to
297    /// declare a symbol as having hidden visibility.
298    MCSymbolAttr HiddenVisibilityAttr;       // Defaults to MCSA_Hidden.
299
300    /// HiddenDeclarationVisibilityAttr - This attribute, if not MCSA_Invalid,
301    /// is used to declare an undefined symbol as having hidden visibility.
302    MCSymbolAttr HiddenDeclarationVisibilityAttr;   // Defaults to MCSA_Hidden.
303
304
305    /// ProtectedVisibilityAttr - This attribute, if not MCSA_Invalid, is used
306    /// to declare a symbol as having protected visibility.
307    MCSymbolAttr ProtectedVisibilityAttr;    // Defaults to MCSA_Protected
308
309    //===--- Dwarf Emission Directives -----------------------------------===//
310
311    /// HasLEB128 - True if target asm supports leb128 directives.
312    bool HasLEB128;                          // Defaults to false.
313
314    /// SupportsDebugInformation - True if target supports emission of debugging
315    /// information.
316    bool SupportsDebugInformation;           // Defaults to false.
317
318    /// SupportsExceptionHandling - True if target supports exception handling.
319    ExceptionHandling::ExceptionsType ExceptionsType; // Defaults to None
320
321    /// DwarfUsesInlineInfoSection - True if DwarfDebugInlineSection is used to
322    /// encode inline subroutine information.
323    bool DwarfUsesInlineInfoSection;         // Defaults to false.
324
325    /// DwarfUsesRelocationsAcrossSections - True if Dwarf2 output generally
326    /// uses relocations for references to other .debug_* sections.
327    bool DwarfUsesRelocationsAcrossSections;
328
329    /// DwarfRegNumForCFI - True if dwarf register numbers are printed
330    /// instead of symbolic register names in .cfi_* directives.
331    bool DwarfRegNumForCFI;  // Defaults to false;
332
333    //===--- Prologue State ----------------------------------------------===//
334
335    std::vector<MachineMove> InitialFrameState;
336
337  public:
338    explicit MCAsmInfo();
339    virtual ~MCAsmInfo();
340
341    // FIXME: move these methods to DwarfPrinter when the JIT stops using them.
342    static unsigned getSLEB128Size(int Value);
343    static unsigned getULEB128Size(unsigned Value);
344
345    /// getPointerSize - Get the pointer size in bytes.
346    unsigned getPointerSize() const {
347      return PointerSize;
348    }
349
350    /// getCalleeSaveStackSlotSize - Get the callee-saved register stack slot
351    /// size in bytes.
352    unsigned getCalleeSaveStackSlotSize() const {
353      return CalleeSaveStackSlotSize;
354    }
355
356    /// isLittleEndian - True if the target is little endian.
357    bool isLittleEndian() const {
358      return IsLittleEndian;
359    }
360
361    /// isStackGrowthDirectionUp - True if target stack grow up.
362    bool isStackGrowthDirectionUp() const {
363      return StackGrowsUp;
364    }
365
366    bool hasSubsectionsViaSymbols() const { return HasSubsectionsViaSymbols; }
367
368    // Data directive accessors.
369    //
370    const char *getData8bitsDirective(unsigned AS = 0) const {
371      return AS == 0 ? Data8bitsDirective : getDataASDirective(8, AS);
372    }
373    const char *getData16bitsDirective(unsigned AS = 0) const {
374      return AS == 0 ? Data16bitsDirective : getDataASDirective(16, AS);
375    }
376    const char *getData32bitsDirective(unsigned AS = 0) const {
377      return AS == 0 ? Data32bitsDirective : getDataASDirective(32, AS);
378    }
379    const char *getData64bitsDirective(unsigned AS = 0) const {
380      return AS == 0 ? Data64bitsDirective : getDataASDirective(64, AS);
381    }
382    const char *getGPRel64Directive() const { return GPRel64Directive; }
383    const char *getGPRel32Directive() const { return GPRel32Directive; }
384
385    /// getNonexecutableStackSection - Targets can implement this method to
386    /// specify a section to switch to if the translation unit doesn't have any
387    /// trampolines that require an executable stack.
388    virtual const MCSection *getNonexecutableStackSection(MCContext &Ctx) const{
389      return 0;
390    }
391
392    virtual const MCExpr *
393    getExprForPersonalitySymbol(const MCSymbol *Sym,
394                                unsigned Encoding,
395                                MCStreamer &Streamer) const;
396
397    const MCExpr *
398    getExprForFDESymbol(const MCSymbol *Sym,
399                        unsigned Encoding,
400                        MCStreamer &Streamer) const;
401
402    bool usesSunStyleELFSectionSwitchSyntax() const {
403      return SunStyleELFSectionSwitchSyntax;
404    }
405
406    bool usesELFSectionDirectiveForBSS() const {
407      return UsesELFSectionDirectiveForBSS;
408    }
409
410    bool hasMicrosoftFastStdCallMangling() const {
411      return HasMicrosoftFastStdCallMangling;
412    }
413
414    bool needsDwarfSectionOffsetDirective() const {
415      return NeedsDwarfSectionOffsetDirective;
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
447    const char *getDebugLabelSuffix() const {
448      return DebugLabelSuffix;
449    }
450
451    const char *getGlobalPrefix() const {
452      return GlobalPrefix;
453    }
454    const char *getPrivateGlobalPrefix() const {
455      return PrivateGlobalPrefix;
456    }
457    const char *getLinkerPrivateGlobalPrefix() const {
458      return LinkerPrivateGlobalPrefix;
459    }
460    const char *getInlineAsmStart() const {
461      return InlineAsmStart;
462    }
463    const char *getInlineAsmEnd() const {
464      return InlineAsmEnd;
465    }
466    const char *getCode16Directive() const {
467      return Code16Directive;
468    }
469    const char *getCode32Directive() const {
470      return Code32Directive;
471    }
472    const char *getCode64Directive() const {
473      return Code64Directive;
474    }
475    unsigned getAssemblerDialect() const {
476      return AssemblerDialect;
477    }
478    bool doesAllowQuotesInName() const {
479      return AllowQuotesInName;
480    }
481    bool doesAllowNameToStartWithDigit() const {
482      return AllowNameToStartWithDigit;
483    }
484    bool doesAllowPeriodsInName() const {
485      return AllowPeriodsInName;
486    }
487    bool doesAllowUTF8() const {
488      return AllowUTF8;
489    }
490    bool doesSupportDataRegionDirectives() const {
491      return UseDataRegionDirectives;
492    }
493    const char *getZeroDirective() const {
494      return ZeroDirective;
495    }
496    const char *getAsciiDirective() const {
497      return AsciiDirective;
498    }
499    const char *getAscizDirective() const {
500      return AscizDirective;
501    }
502    const char *getAlignDirective() const {
503      return AlignDirective;
504    }
505    bool getAlignmentIsInBytes() const {
506      return AlignmentIsInBytes;
507    }
508    unsigned getTextAlignFillValue() const {
509      return TextAlignFillValue;
510    }
511    const char *getGlobalDirective() const {
512      return GlobalDirective;
513    }
514    const char *getExternDirective() const {
515      return ExternDirective;
516    }
517    bool hasSetDirective() const { return HasSetDirective; }
518    bool hasAggressiveSymbolFolding() const {
519      return HasAggressiveSymbolFolding;
520    }
521    bool getCOMMDirectiveAlignmentIsInBytes() const {
522      return COMMDirectiveAlignmentIsInBytes;
523    }
524    LCOMM::LCOMMType getLCOMMDirectiveAlignmentType() const {
525      return LCOMMDirectiveAlignmentType;
526    }
527    bool hasDotTypeDotSizeDirective() const {return HasDotTypeDotSizeDirective;}
528    bool hasSingleParameterDotFile() const { return HasSingleParameterDotFile; }
529    bool hasNoDeadStrip() const { return HasNoDeadStrip; }
530    bool hasSymbolResolver() const { return HasSymbolResolver; }
531    const char *getWeakRefDirective() const { return WeakRefDirective; }
532    const char *getWeakDefDirective() const { return WeakDefDirective; }
533    const char *getLinkOnceDirective() const { return LinkOnceDirective; }
534
535    MCSymbolAttr getHiddenVisibilityAttr() const { return HiddenVisibilityAttr;}
536    MCSymbolAttr getHiddenDeclarationVisibilityAttr() const {
537      return HiddenDeclarationVisibilityAttr;
538    }
539    MCSymbolAttr getProtectedVisibilityAttr() const {
540      return ProtectedVisibilityAttr;
541    }
542    bool hasLEB128() const {
543      return HasLEB128;
544    }
545    bool doesSupportDebugInformation() const {
546      return SupportsDebugInformation;
547    }
548    bool doesSupportExceptionHandling() const {
549      return ExceptionsType != ExceptionHandling::None;
550    }
551    ExceptionHandling::ExceptionsType getExceptionHandlingType() const {
552      return ExceptionsType;
553    }
554    bool isExceptionHandlingDwarf() const {
555      return
556        (ExceptionsType == ExceptionHandling::DwarfCFI ||
557         ExceptionsType == ExceptionHandling::ARM ||
558         ExceptionsType == ExceptionHandling::Win64);
559    }
560    bool doesDwarfUseInlineInfoSection() const {
561      return DwarfUsesInlineInfoSection;
562    }
563    bool doesDwarfUseRelocationsAcrossSections() const {
564      return DwarfUsesRelocationsAcrossSections;
565    }
566    bool useDwarfRegNumForCFI() const {
567      return DwarfRegNumForCFI;
568    }
569
570    void addInitialFrameState(MCSymbol *label, const MachineLocation &D,
571                              const MachineLocation &S) {
572      InitialFrameState.push_back(MachineMove(label, D, S));
573    }
574    const std::vector<MachineMove> &getInitialFrameState() const {
575      return InitialFrameState;
576    }
577  };
578}
579
580#endif
581