MCAsmInfo.h revision 6b6345f0167fb9ddf60bdc51d616d7a9ae590442 
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    /// PCSymbol - The symbol used to represent the current PC.  Used in PC
97    /// relative expressions.
98    const char *PCSymbol;                    // Defaults to "$".
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    /// AllowUTF8 - This is true if the assembler accepts UTF-8 input.
160    // FIXME: Make this a more general encoding setting?
161    bool AllowUTF8;
162
163    /// UseDataRegionDirectives - This is true if data region markers should
164    /// be printed as ".data_region/.end_data_region" directives. If false,
165    /// use "$d/$a" labels instead.
166    bool UseDataRegionDirectives;
167
168    //===--- Data Emission Directives -------------------------------------===//
169
170    /// ZeroDirective - this should be set to the directive used to get some
171    /// number of zero bytes emitted to the current section.  Common cases are
172    /// "\t.zero\t" and "\t.space\t".  If this is set to null, the
173    /// Data*bitsDirective's will be used to emit zero bytes.
174    const char *ZeroDirective;               // Defaults to "\t.zero\t"
175
176    /// AsciiDirective - This directive allows emission of an ascii string with
177    /// the standard C escape characters embedded into it.
178    const char *AsciiDirective;              // Defaults to "\t.ascii\t"
179
180    /// AscizDirective - If not null, this allows for special handling of
181    /// zero terminated strings on this target.  This is commonly supported as
182    /// ".asciz".  If a target doesn't support this, it can be set to null.
183    const char *AscizDirective;              // Defaults to "\t.asciz\t"
184
185    /// DataDirectives - These directives are used to output some unit of
186    /// integer data to the current section.  If a data directive is set to
187    /// null, smaller data directives will be used to emit the large sizes.
188    const char *Data8bitsDirective;          // Defaults to "\t.byte\t"
189    const char *Data16bitsDirective;         // Defaults to "\t.short\t"
190    const char *Data32bitsDirective;         // Defaults to "\t.long\t"
191    const char *Data64bitsDirective;         // Defaults to "\t.quad\t"
192
193    /// GPRel64Directive - if non-null, a directive that is used to emit a word
194    /// which should be relocated as a 64-bit GP-relative offset, e.g. .gpdword
195    /// on Mips.
196    const char *GPRel64Directive;            // Defaults to NULL.
197
198    /// GPRel32Directive - if non-null, a directive that is used to emit a word
199    /// which should be relocated as a 32-bit GP-relative offset, e.g. .gpword
200    /// on Mips or .gprel32 on Alpha.
201    const char *GPRel32Directive;            // Defaults to NULL.
202
203    /// SunStyleELFSectionSwitchSyntax - This is true if this target uses "Sun
204    /// Style" syntax for section switching ("#alloc,#write" etc) instead of the
205    /// normal ELF syntax (,"a,w") in .section directives.
206    bool SunStyleELFSectionSwitchSyntax;     // Defaults to false.
207
208    /// UsesELFSectionDirectiveForBSS - This is true if this target uses ELF
209    /// '.section' directive before the '.bss' one. It's used for PPC/Linux
210    /// which doesn't support the '.bss' directive only.
211    bool UsesELFSectionDirectiveForBSS;      // Defaults to false.
212
213    /// HasMicrosoftFastStdCallMangling - True if this target uses microsoft
214    /// style mangling for functions with X86_StdCall/X86_FastCall calling
215    /// convention.
216    bool HasMicrosoftFastStdCallMangling;    // Defaults to false.
217
218    bool NeedsDwarfSectionOffsetDirective;
219
220    //===--- Alignment Information ----------------------------------------===//
221
222    /// AlignDirective - The directive used to emit round up to an alignment
223    /// boundary.
224    ///
225    const char *AlignDirective;              // Defaults to "\t.align\t"
226
227    /// AlignmentIsInBytes - If this is true (the default) then the asmprinter
228    /// emits ".align N" directives, where N is the number of bytes to align to.
229    /// Otherwise, it emits ".align log2(N)", e.g. 3 to align to an 8 byte
230    /// boundary.
231    bool AlignmentIsInBytes;                 // Defaults to true
232
233    /// TextAlignFillValue - If non-zero, this is used to fill the executable
234    /// space created as the result of a alignment directive.
235    unsigned TextAlignFillValue;             // Defaults to 0
236
237    //===--- Global Variable Emission Directives --------------------------===//
238
239    /// GlobalDirective - This is the directive used to declare a global entity.
240    ///
241    const char *GlobalDirective;             // Defaults to NULL.
242
243    /// ExternDirective - This is the directive used to declare external
244    /// globals.
245    ///
246    const char *ExternDirective;             // Defaults to NULL.
247
248    /// HasSetDirective - True if the assembler supports the .set directive.
249    bool HasSetDirective;                    // Defaults to true.
250
251    /// HasAggressiveSymbolFolding - False if the assembler requires that we use
252    /// Lc = a - b
253    /// .long Lc
254    /// instead of
255    /// .long a - b
256    bool HasAggressiveSymbolFolding;           // Defaults to true.
257
258    /// COMMDirectiveAlignmentIsInBytes - True is .comm's and .lcomms optional
259    /// alignment is to be specified in bytes instead of log2(n).
260    bool COMMDirectiveAlignmentIsInBytes;    // Defaults to true;
261
262    /// LCOMMDirectiveAlignment - Describes if the .lcomm directive for the
263    /// target supports an alignment argument and how it is interpreted.
264    LCOMM::LCOMMType LCOMMDirectiveAlignmentType; // Defaults to NoAlignment.
265
266    /// HasDotTypeDotSizeDirective - True if the target has .type and .size
267    /// directives, this is true for most ELF targets.
268    bool HasDotTypeDotSizeDirective;         // Defaults to true.
269
270    /// HasSingleParameterDotFile - True if the target has a single parameter
271    /// .file directive, this is true for ELF targets.
272    bool HasSingleParameterDotFile;          // Defaults to true.
273
274    /// HasNoDeadStrip - True if this target supports the MachO .no_dead_strip
275    /// directive.
276    bool HasNoDeadStrip;                     // Defaults to false.
277
278    /// HasSymbolResolver - True if this target supports the MachO
279    /// .symbol_resolver directive.
280    bool HasSymbolResolver;                     // Defaults to false.
281
282    /// WeakRefDirective - This directive, if non-null, is used to declare a
283    /// global as being a weak undefined symbol.
284    const char *WeakRefDirective;            // Defaults to NULL.
285
286    /// WeakDefDirective - This directive, if non-null, is used to declare a
287    /// global as being a weak defined symbol.
288    const char *WeakDefDirective;            // Defaults to NULL.
289
290    /// LinkOnceDirective - This directive, if non-null is used to declare a
291    /// global as being a weak defined symbol.  This is used on cygwin/mingw.
292    const char *LinkOnceDirective;           // Defaults to NULL.
293
294    /// HiddenVisibilityAttr - This attribute, if not MCSA_Invalid, is used to
295    /// declare a symbol as having hidden visibility.
296    MCSymbolAttr HiddenVisibilityAttr;       // Defaults to MCSA_Hidden.
297
298    /// HiddenDeclarationVisibilityAttr - This attribute, if not MCSA_Invalid,
299    /// is used to declare an undefined symbol as having hidden visibility.
300    MCSymbolAttr HiddenDeclarationVisibilityAttr;   // Defaults to MCSA_Hidden.
301
302
303    /// ProtectedVisibilityAttr - This attribute, if not MCSA_Invalid, is used
304    /// to declare a symbol as having protected visibility.
305    MCSymbolAttr ProtectedVisibilityAttr;    // Defaults to MCSA_Protected
306
307    //===--- Dwarf Emission Directives -----------------------------------===//
308
309    /// HasLEB128 - True if target asm supports leb128 directives.
310    bool HasLEB128;                          // Defaults to false.
311
312    /// SupportsDebugInformation - True if target supports emission of debugging
313    /// information.
314    bool SupportsDebugInformation;           // Defaults to false.
315
316    /// SupportsExceptionHandling - True if target supports exception handling.
317    ExceptionHandling::ExceptionsType ExceptionsType; // Defaults to None
318
319    /// DwarfUsesRelocationsAcrossSections - True if Dwarf2 output generally
320    /// uses relocations for references to other .debug_* sections.
321    bool DwarfUsesRelocationsAcrossSections;
322
323    /// DwarfRegNumForCFI - True if dwarf register numbers are printed
324    /// instead of symbolic register names in .cfi_* directives.
325    bool DwarfRegNumForCFI;  // Defaults to false;
326
327    //===--- Prologue State ----------------------------------------------===//
328
329    std::vector<MCCFIInstruction> InitialFrameState;
330
331  public:
332    explicit MCAsmInfo();
333    virtual ~MCAsmInfo();
334
335    // FIXME: move these methods to DwarfPrinter when the JIT stops using them.
336    static unsigned getSLEB128Size(int64_t Value);
337    static unsigned getULEB128Size(uint64_t Value);
338
339    /// getPointerSize - Get the pointer size in bytes.
340    unsigned getPointerSize() const {
341      return PointerSize;
342    }
343
344    /// getCalleeSaveStackSlotSize - Get the callee-saved register stack slot
345    /// size in bytes.
346    unsigned getCalleeSaveStackSlotSize() const {
347      return CalleeSaveStackSlotSize;
348    }
349
350    /// isLittleEndian - True if the target is little endian.
351    bool isLittleEndian() const {
352      return IsLittleEndian;
353    }
354
355    /// isStackGrowthDirectionUp - True if target stack grow up.
356    bool isStackGrowthDirectionUp() const {
357      return StackGrowsUp;
358    }
359
360    bool hasSubsectionsViaSymbols() const { return HasSubsectionsViaSymbols; }
361
362    // Data directive accessors.
363    //
364    const char *getData8bitsDirective() const {
365      return Data8bitsDirective;
366    }
367    const char *getData16bitsDirective() const {
368      return Data16bitsDirective;
369    }
370    const char *getData32bitsDirective() const {
371      return Data32bitsDirective;
372    }
373    const char *getData64bitsDirective() const {
374      return Data64bitsDirective;
375    }
376    const char *getGPRel64Directive() const { return GPRel64Directive; }
377    const char *getGPRel32Directive() const { return GPRel32Directive; }
378
379    /// getNonexecutableStackSection - Targets can implement this method to
380    /// specify a section to switch to if the translation unit doesn't have any
381    /// trampolines that require an executable stack.
382    virtual const MCSection *getNonexecutableStackSection(MCContext &Ctx) const{
383      return 0;
384    }
385
386    virtual const MCExpr *
387    getExprForPersonalitySymbol(const MCSymbol *Sym,
388                                unsigned Encoding,
389                                MCStreamer &Streamer) const;
390
391    const MCExpr *
392    getExprForFDESymbol(const MCSymbol *Sym,
393                        unsigned Encoding,
394                        MCStreamer &Streamer) const;
395
396    bool usesSunStyleELFSectionSwitchSyntax() const {
397      return SunStyleELFSectionSwitchSyntax;
398    }
399
400    bool usesELFSectionDirectiveForBSS() const {
401      return UsesELFSectionDirectiveForBSS;
402    }
403
404    bool hasMicrosoftFastStdCallMangling() const {
405      return HasMicrosoftFastStdCallMangling;
406    }
407
408    bool needsDwarfSectionOffsetDirective() const {
409      return NeedsDwarfSectionOffsetDirective;
410    }
411
412    // Accessors.
413    //
414    bool hasMachoZeroFillDirective() const { return HasMachoZeroFillDirective; }
415    bool hasMachoTBSSDirective() const { return HasMachoTBSSDirective; }
416    bool hasStaticCtorDtorReferenceInStaticMode() const {
417      return HasStaticCtorDtorReferenceInStaticMode;
418    }
419    bool getLinkerRequiresNonEmptyDwarfLines() const {
420      return LinkerRequiresNonEmptyDwarfLines;
421    }
422    unsigned getMaxInstLength() const {
423      return MaxInstLength;
424    }
425    unsigned getMinInstAlignment() const {
426      return MinInstAlignment;
427    }
428    const char *getPCSymbol() const {
429      return PCSymbol;
430    }
431    const char *getSeparatorString() const {
432      return SeparatorString;
433    }
434    unsigned getCommentColumn() const {
435      return CommentColumn;
436    }
437    const char *getCommentString() const {
438      return CommentString;
439    }
440    const char *getLabelSuffix() const {
441      return LabelSuffix;
442    }
443
444    const char *getDebugLabelSuffix() const {
445      return DebugLabelSuffix;
446    }
447
448    const char *getGlobalPrefix() const {
449      return GlobalPrefix;
450    }
451    const char *getPrivateGlobalPrefix() const {
452      return PrivateGlobalPrefix;
453    }
454    const char *getLinkerPrivateGlobalPrefix() const {
455      return LinkerPrivateGlobalPrefix;
456    }
457    const char *getInlineAsmStart() const {
458      return InlineAsmStart;
459    }
460    const char *getInlineAsmEnd() const {
461      return InlineAsmEnd;
462    }
463    const char *getCode16Directive() const {
464      return Code16Directive;
465    }
466    const char *getCode32Directive() const {
467      return Code32Directive;
468    }
469    const char *getCode64Directive() const {
470      return Code64Directive;
471    }
472    unsigned getAssemblerDialect() const {
473      return AssemblerDialect;
474    }
475    bool doesAllowQuotesInName() const {
476      return AllowQuotesInName;
477    }
478    bool doesAllowNameToStartWithDigit() const {
479      return AllowNameToStartWithDigit;
480    }
481    bool doesAllowPeriodsInName() const {
482      return AllowPeriodsInName;
483    }
484    bool doesAllowUTF8() const {
485      return AllowUTF8;
486    }
487    bool doesSupportDataRegionDirectives() const {
488      return UseDataRegionDirectives;
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    bool getCOMMDirectiveAlignmentIsInBytes() const {
519      return COMMDirectiveAlignmentIsInBytes;
520    }
521    LCOMM::LCOMMType getLCOMMDirectiveAlignmentType() const {
522      return LCOMMDirectiveAlignmentType;
523    }
524    bool hasDotTypeDotSizeDirective() const {return HasDotTypeDotSizeDirective;}
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 doesDwarfUseRelocationsAcrossSections() const {
558      return DwarfUsesRelocationsAcrossSections;
559    }
560    bool useDwarfRegNumForCFI() const {
561      return DwarfRegNumForCFI;
562    }
563
564    void addInitialFrameState(const MCCFIInstruction &Inst) {
565      InitialFrameState.push_back(Inst);
566    }
567
568    const std::vector<MCCFIInstruction> &getInitialFrameState() const {
569      return InitialFrameState;
570    }
571  };
572}
573
574#endif
575