MCAsmInfo.h revision 2d28617de2b0b731c08d1af9e830f31e14ac75b4 
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  /// MCAsmInfo - This class is intended to be used as a base class for asm
36  /// properties and features specific to the target.
37  class MCAsmInfo {
38  protected:
39    //===------------------------------------------------------------------===//
40    // Properties to be set by the target writer, used to configure asm printer.
41    //
42
43    /// PointerSize - Pointer size in bytes.
44    ///               Default is 4.
45    unsigned PointerSize;
46
47    /// IsLittleEndian - True if target is little endian.
48    ///                  Default is true.
49    bool IsLittleEndian;
50
51    /// StackGrowsUp - True if target stack grow up.
52    ///                Default is false.
53    bool StackGrowsUp;
54
55    /// HasSubsectionsViaSymbols - True if this target has the MachO
56    /// .subsections_via_symbols directive.
57    bool HasSubsectionsViaSymbols;           // Default is false.
58
59    /// HasMachoZeroFillDirective - True if this is a MachO target that supports
60    /// the macho-specific .zerofill directive for emitting BSS Symbols.
61    bool HasMachoZeroFillDirective;               // Default is false.
62
63    /// HasMachoTBSSDirective - True if this is a MachO target that supports
64    /// the macho-specific .tbss directive for emitting thread local BSS Symbols
65    bool HasMachoTBSSDirective;                 // Default is false.
66
67    /// HasStaticCtorDtorReferenceInStaticMode - True if the compiler should
68    /// emit a ".reference .constructors_used" or ".reference .destructors_used"
69    /// directive after the a static ctor/dtor list.  This directive is only
70    /// emitted in Static relocation model.
71    bool HasStaticCtorDtorReferenceInStaticMode;  // Default is false.
72
73    /// LinkerRequiresNonEmptyDwarfLines - True if the linker has a bug and
74    /// requires that the debug_line section be of a minimum size. In practice
75    /// such a linker requires a non empty line sequence if a file is present.
76    bool LinkerRequiresNonEmptyDwarfLines; // Default to false.
77
78    /// MaxInstLength - This is the maximum possible length of an instruction,
79    /// which is needed to compute the size of an inline asm.
80    unsigned MaxInstLength;                  // Defaults to 4.
81
82    /// PCSymbol - The symbol used to represent the current PC.  Used in PC
83    /// relative expressions.
84    const char *PCSymbol;                    // Defaults to "$".
85
86    /// SeparatorString - This string, if specified, is used to separate
87    /// instructions from each other when on the same line.
88    const char *SeparatorString;             // Defaults to ';'
89
90    /// CommentColumn - This indicates the comment num (zero-based) at
91    /// which asm comments should be printed.
92    unsigned CommentColumn;                  // Defaults to 40
93
94    /// CommentString - This indicates the comment character used by the
95    /// assembler.
96    const char *CommentString;               // Defaults to "#"
97
98    /// LabelSuffix - This is appended to emitted labels.
99    const char *LabelSuffix;                 // Defaults to ":"
100
101    /// GlobalPrefix - If this is set to a non-empty string, it is prepended
102    /// onto all global symbols.  This is often used for "_" or ".".
103    const char *GlobalPrefix;                // Defaults to ""
104
105    /// PrivateGlobalPrefix - This prefix is used for globals like constant
106    /// pool entries that are completely private to the .s file and should not
107    /// have names in the .o file.  This is often "." or "L".
108    const char *PrivateGlobalPrefix;         // Defaults to "."
109
110    /// LinkerPrivateGlobalPrefix - This prefix is used for symbols that should
111    /// be passed through the assembler but be removed by the linker.  This
112    /// is "l" on Darwin, currently used for some ObjC metadata.
113    const char *LinkerPrivateGlobalPrefix;   // Defaults to ""
114
115    /// InlineAsmStart/End - If these are nonempty, they contain a directive to
116    /// emit before and after an inline assembly statement.
117    const char *InlineAsmStart;              // Defaults to "#APP\n"
118    const char *InlineAsmEnd;                // Defaults to "#NO_APP\n"
119
120    /// AssemblerDialect - Which dialect of an assembler variant to use.
121    unsigned AssemblerDialect;               // Defaults to 0
122
123    /// AllowQuotesInName - This is true if the assembler allows for complex
124    /// symbol names to be surrounded in quotes.  This defaults to false.
125    bool AllowQuotesInName;
126
127    /// AllowNameToStartWithDigit - This is true if the assembler allows symbol
128    /// names to start with a digit (e.g., "0x0021").  This defaults to false.
129    bool AllowNameToStartWithDigit;
130
131    /// AllowPeriodsInName - This is true if the assembler allows periods in
132    /// symbol names.  This defaults to true.
133    bool AllowPeriodsInName;
134
135    //===--- Data Emission Directives -------------------------------------===//
136
137    /// ZeroDirective - this should be set to the directive used to get some
138    /// number of zero bytes emitted to the current section.  Common cases are
139    /// "\t.zero\t" and "\t.space\t".  If this is set to null, the
140    /// Data*bitsDirective's will be used to emit zero bytes.
141    const char *ZeroDirective;               // Defaults to "\t.zero\t"
142
143    /// AsciiDirective - This directive allows emission of an ascii string with
144    /// the standard C escape characters embedded into it.
145    const char *AsciiDirective;              // Defaults to "\t.ascii\t"
146
147    /// AscizDirective - If not null, this allows for special handling of
148    /// zero terminated strings on this target.  This is commonly supported as
149    /// ".asciz".  If a target doesn't support this, it can be set to null.
150    const char *AscizDirective;              // Defaults to "\t.asciz\t"
151
152    /// DataDirectives - These directives are used to output some unit of
153    /// integer data to the current section.  If a data directive is set to
154    /// null, smaller data directives will be used to emit the large sizes.
155    const char *Data8bitsDirective;          // Defaults to "\t.byte\t"
156    const char *Data16bitsDirective;         // Defaults to "\t.short\t"
157    const char *Data32bitsDirective;         // Defaults to "\t.long\t"
158    const char *Data64bitsDirective;         // Defaults to "\t.quad\t"
159
160    /// GPRel32Directive - if non-null, a directive that is used to emit a word
161    /// which should be relocated as a 32-bit GP-relative offset, e.g. .gpword
162    /// on Mips or .gprel32 on Alpha.
163    const char *GPRel32Directive;            // Defaults to NULL.
164
165    /// getDataASDirective - Return the directive that should be used to emit
166    /// data of the specified size to the specified numeric address space.
167    virtual const char *getDataASDirective(unsigned Size, unsigned AS) const {
168      assert(AS != 0 && "Don't know the directives for default addr space");
169      return 0;
170    }
171
172    /// SunStyleELFSectionSwitchSyntax - This is true if this target uses "Sun
173    /// Style" syntax for section switching ("#alloc,#write" etc) instead of the
174    /// normal ELF syntax (,"a,w") in .section directives.
175    bool SunStyleELFSectionSwitchSyntax;     // Defaults to false.
176
177    /// UsesELFSectionDirectiveForBSS - This is true if this target uses ELF
178    /// '.section' directive before the '.bss' one. It's used for PPC/Linux
179    /// which doesn't support the '.bss' directive only.
180    bool UsesELFSectionDirectiveForBSS;      // Defaults to false.
181
182    /// HasMicrosoftFastStdCallMangling - True if this target uses microsoft
183    /// style mangling for functions with X86_StdCall/X86_FastCall calling
184    /// convention.
185    bool HasMicrosoftFastStdCallMangling;    // Defaults to false.
186
187    //===--- Alignment Information ----------------------------------------===//
188
189    /// AlignDirective - The directive used to emit round up to an alignment
190    /// boundary.
191    ///
192    const char *AlignDirective;              // Defaults to "\t.align\t"
193
194    /// AlignmentIsInBytes - If this is true (the default) then the asmprinter
195    /// emits ".align N" directives, where N is the number of bytes to align to.
196    /// Otherwise, it emits ".align log2(N)", e.g. 3 to align to an 8 byte
197    /// boundary.
198    bool AlignmentIsInBytes;                 // Defaults to true
199
200    /// TextAlignFillValue - If non-zero, this is used to fill the executable
201    /// space created as the result of a alignment directive.
202    unsigned TextAlignFillValue;             // Defaults to 0
203
204    //===--- Global Variable Emission Directives --------------------------===//
205
206    /// GlobalDirective - This is the directive used to declare a global entity.
207    ///
208    const char *GlobalDirective;             // Defaults to NULL.
209
210    /// ExternDirective - This is the directive used to declare external
211    /// globals.
212    ///
213    const char *ExternDirective;             // Defaults to NULL.
214
215    /// HasSetDirective - True if the assembler supports the .set directive.
216    bool HasSetDirective;                    // Defaults to true.
217
218    /// HasAggressiveSymbolFolding - False if the assembler requires that we use
219    /// Lc = a - b
220    /// .long Lc
221    /// instead of
222    /// .long a - b
223    bool HasAggressiveSymbolFolding;           // Defaults to true.
224
225    /// HasLCOMMDirective - This is true if the target supports the .lcomm
226    /// directive.
227    bool HasLCOMMDirective;                  // Defaults to false.
228
229    /// COMMDirectiveAlignmentIsInBytes - True is COMMDirective's optional
230    /// alignment is to be specified in bytes instead of log2(n).
231    bool COMMDirectiveAlignmentIsInBytes;    // Defaults to true;
232
233    /// HasDotTypeDotSizeDirective - True if the target has .type and .size
234    /// directives, this is true for most ELF targets.
235    bool HasDotTypeDotSizeDirective;         // Defaults to true.
236
237    /// HasSingleParameterDotFile - True if the target has a single parameter
238    /// .file directive, this is true for ELF targets.
239    bool HasSingleParameterDotFile;          // Defaults to true.
240
241    /// HasNoDeadStrip - True if this target supports the MachO .no_dead_strip
242    /// directive.
243    bool HasNoDeadStrip;                     // Defaults to false.
244
245    /// HasSymbolResolver - True if this target supports the MachO
246    /// .symbol_resolver directive.
247    bool HasSymbolResolver;                     // Defaults to false.
248
249    /// WeakRefDirective - This directive, if non-null, is used to declare a
250    /// global as being a weak undefined symbol.
251    const char *WeakRefDirective;            // Defaults to NULL.
252
253    /// WeakDefDirective - This directive, if non-null, is used to declare a
254    /// global as being a weak defined symbol.
255    const char *WeakDefDirective;            // Defaults to NULL.
256
257    /// LinkOnceDirective - This directive, if non-null is used to declare a
258    /// global as being a weak defined symbol.  This is used on cygwin/mingw.
259    const char *LinkOnceDirective;           // Defaults to NULL.
260
261    /// HiddenVisibilityAttr - This attribute, if not MCSA_Invalid, is used to
262    /// declare a symbol as having hidden visibility.
263    MCSymbolAttr HiddenVisibilityAttr;       // Defaults to MCSA_Hidden.
264
265    /// HiddenDeclarationVisibilityAttr - This attribute, if not MCSA_Invalid,
266    /// is used to declare an undefined symbol as having hidden visibility.
267    MCSymbolAttr HiddenDeclarationVisibilityAttr;   // Defaults to MCSA_Hidden.
268
269
270    /// ProtectedVisibilityAttr - This attribute, if not MCSA_Invalid, is used
271    /// to declare a symbol as having protected visibility.
272    MCSymbolAttr ProtectedVisibilityAttr;    // Defaults to MCSA_Protected
273
274    //===--- Dwarf Emission Directives -----------------------------------===//
275
276    /// HasLEB128 - True if target asm supports leb128 directives.
277    bool HasLEB128;                          // Defaults to false.
278
279    /// SupportsDebugInformation - True if target supports emission of debugging
280    /// information.
281    bool SupportsDebugInformation;           // Defaults to false.
282
283    /// SupportsExceptionHandling - True if target supports exception handling.
284    ExceptionHandling::ExceptionsType ExceptionsType; // Defaults to None
285
286    /// DwarfUsesInlineInfoSection - True if DwarfDebugInlineSection is used to
287    /// encode inline subroutine information.
288    bool DwarfUsesInlineInfoSection;         // Defaults to false.
289
290    /// DwarfSectionOffsetDirective - Special section offset directive.
291    const char* DwarfSectionOffsetDirective; // Defaults to NULL
292
293    /// DwarfRequiresRelocationForSectionOffset - True if we need to produce a
294    // relocation when we want a section offset in dwarf.
295    bool DwarfRequiresRelocationForSectionOffset;  // Defaults to true;
296
297    // DwarfUsesLabelOffsetDifference - True if Dwarf2 output can
298    // use EmitLabelOffsetDifference.
299    bool DwarfUsesLabelOffsetForRanges;
300
301    /// DwarfRegNumForCFI - True if dwarf register numbers are printed
302    /// instead of symbolic register names in .cfi_* directives.
303    bool DwarfRegNumForCFI;  // Defaults to false;
304
305    //===--- CBE Asm Translation Table -----------------------------------===//
306
307    const char *const *AsmTransCBE;          // Defaults to empty
308
309    //===--- Prologue State ----------------------------------------------===//
310
311    std::vector<MachineMove> InitialFrameState;
312
313  public:
314    explicit MCAsmInfo();
315    virtual ~MCAsmInfo();
316
317    // FIXME: move these methods to DwarfPrinter when the JIT stops using them.
318    static unsigned getSLEB128Size(int Value);
319    static unsigned getULEB128Size(unsigned Value);
320
321    /// getPointerSize - Get the pointer size in bytes.
322    unsigned getPointerSize() const {
323      return PointerSize;
324    }
325
326    /// islittleendian - True if the target is little endian.
327    bool isLittleEndian() const {
328      return IsLittleEndian;
329    }
330
331    /// isStackGrowthDirectionUp - True if target stack grow up.
332    bool isStackGrowthDirectionUp() const {
333      return StackGrowsUp;
334    }
335
336    bool hasSubsectionsViaSymbols() const { return HasSubsectionsViaSymbols; }
337
338    // Data directive accessors.
339    //
340    const char *getData8bitsDirective(unsigned AS = 0) const {
341      return AS == 0 ? Data8bitsDirective : getDataASDirective(8, AS);
342    }
343    const char *getData16bitsDirective(unsigned AS = 0) const {
344      return AS == 0 ? Data16bitsDirective : getDataASDirective(16, AS);
345    }
346    const char *getData32bitsDirective(unsigned AS = 0) const {
347      return AS == 0 ? Data32bitsDirective : getDataASDirective(32, AS);
348    }
349    const char *getData64bitsDirective(unsigned AS = 0) const {
350      return AS == 0 ? Data64bitsDirective : getDataASDirective(64, AS);
351    }
352    const char *getGPRel32Directive() const { return GPRel32Directive; }
353
354    /// getNonexecutableStackSection - Targets can implement this method to
355    /// specify a section to switch to if the translation unit doesn't have any
356    /// trampolines that require an executable stack.
357    virtual const MCSection *getNonexecutableStackSection(MCContext &Ctx) const{
358      return 0;
359    }
360
361    virtual const MCExpr *
362    getExprForPersonalitySymbol(const MCSymbol *Sym,
363                                unsigned Encoding,
364                                MCStreamer &Streamer) const;
365
366    const MCExpr *
367    getExprForFDESymbol(const MCSymbol *Sym,
368                        unsigned Encoding,
369                        MCStreamer &Streamer) const;
370
371    bool usesSunStyleELFSectionSwitchSyntax() const {
372      return SunStyleELFSectionSwitchSyntax;
373    }
374
375    bool usesELFSectionDirectiveForBSS() const {
376      return UsesELFSectionDirectiveForBSS;
377    }
378
379    bool hasMicrosoftFastStdCallMangling() const {
380      return HasMicrosoftFastStdCallMangling;
381    }
382
383    // Accessors.
384    //
385    bool hasMachoZeroFillDirective() const { return HasMachoZeroFillDirective; }
386    bool hasMachoTBSSDirective() const { return HasMachoTBSSDirective; }
387    bool hasStaticCtorDtorReferenceInStaticMode() const {
388      return HasStaticCtorDtorReferenceInStaticMode;
389    }
390    bool getLinkerRequiresNonEmptyDwarfLines() const {
391      return LinkerRequiresNonEmptyDwarfLines;
392    }
393    unsigned getMaxInstLength() const {
394      return MaxInstLength;
395    }
396    const char *getPCSymbol() const {
397      return PCSymbol;
398    }
399    const char *getSeparatorString() const {
400      return SeparatorString;
401    }
402    unsigned getCommentColumn() const {
403      return CommentColumn;
404    }
405    const char *getCommentString() const {
406      return CommentString;
407    }
408    const char *getLabelSuffix() const {
409      return LabelSuffix;
410    }
411    const char *getGlobalPrefix() const {
412      return GlobalPrefix;
413    }
414    const char *getPrivateGlobalPrefix() const {
415      return PrivateGlobalPrefix;
416    }
417    const char *getLinkerPrivateGlobalPrefix() const {
418      return LinkerPrivateGlobalPrefix;
419    }
420    const char *getInlineAsmStart() const {
421      return InlineAsmStart;
422    }
423    const char *getInlineAsmEnd() const {
424      return InlineAsmEnd;
425    }
426    unsigned getAssemblerDialect() const {
427      return AssemblerDialect;
428    }
429    bool doesAllowQuotesInName() const {
430      return AllowQuotesInName;
431    }
432    bool doesAllowNameToStartWithDigit() const {
433      return AllowNameToStartWithDigit;
434    }
435    bool doesAllowPeriodsInName() const {
436      return AllowPeriodsInName;
437    }
438    const char *getZeroDirective() const {
439      return ZeroDirective;
440    }
441    const char *getAsciiDirective() const {
442      return AsciiDirective;
443    }
444    const char *getAscizDirective() const {
445      return AscizDirective;
446    }
447    const char *getAlignDirective() const {
448      return AlignDirective;
449    }
450    bool getAlignmentIsInBytes() const {
451      return AlignmentIsInBytes;
452    }
453    unsigned getTextAlignFillValue() const {
454      return TextAlignFillValue;
455    }
456    const char *getGlobalDirective() const {
457      return GlobalDirective;
458    }
459    const char *getExternDirective() const {
460      return ExternDirective;
461    }
462    bool hasSetDirective() const { return HasSetDirective; }
463    bool hasAggressiveSymbolFolding() const {
464      return HasAggressiveSymbolFolding;
465    }
466    bool hasLCOMMDirective() const { return HasLCOMMDirective; }
467    bool hasDotTypeDotSizeDirective() const {return HasDotTypeDotSizeDirective;}
468    bool getCOMMDirectiveAlignmentIsInBytes() const {
469      return COMMDirectiveAlignmentIsInBytes;
470    }
471    bool hasSingleParameterDotFile() const { return HasSingleParameterDotFile; }
472    bool hasNoDeadStrip() const { return HasNoDeadStrip; }
473    bool hasSymbolResolver() const { return HasSymbolResolver; }
474    const char *getWeakRefDirective() const { return WeakRefDirective; }
475    const char *getWeakDefDirective() const { return WeakDefDirective; }
476    const char *getLinkOnceDirective() const { return LinkOnceDirective; }
477
478    MCSymbolAttr getHiddenVisibilityAttr() const { return HiddenVisibilityAttr;}
479    MCSymbolAttr getHiddenDeclarationVisibilityAttr() const {
480      return HiddenDeclarationVisibilityAttr;
481    }
482    MCSymbolAttr getProtectedVisibilityAttr() const {
483      return ProtectedVisibilityAttr;
484    }
485    bool hasLEB128() const {
486      return HasLEB128;
487    }
488    bool doesSupportDebugInformation() const {
489      return SupportsDebugInformation;
490    }
491    bool doesSupportExceptionHandling() const {
492      return ExceptionsType != ExceptionHandling::None;
493    }
494    ExceptionHandling::ExceptionsType getExceptionHandlingType() const {
495      return ExceptionsType;
496    }
497    bool isExceptionHandlingDwarf() const {
498      return
499        (ExceptionsType == ExceptionHandling::DwarfCFI ||
500         ExceptionsType == ExceptionHandling::ARM ||
501         ExceptionsType == ExceptionHandling::Win64);
502    }
503    bool doesDwarfUsesInlineInfoSection() const {
504      return DwarfUsesInlineInfoSection;
505    }
506    const char *getDwarfSectionOffsetDirective() const {
507      return DwarfSectionOffsetDirective;
508    }
509    bool doesDwarfRequireRelocationForSectionOffset() const {
510      return DwarfRequiresRelocationForSectionOffset;
511    }
512    bool doesDwarfUsesLabelOffsetForRanges() const {
513      return DwarfUsesLabelOffsetForRanges;
514    }
515    bool useDwarfRegNumForCFI() const {
516      return DwarfRegNumForCFI;
517    }
518    const char *const *getAsmCBE() const {
519      return AsmTransCBE;
520    }
521
522    void addInitialFrameState(MCSymbol *label, const MachineLocation &D,
523                              const MachineLocation &S) {
524      InitialFrameState.push_back(MachineMove(label, D, S));
525    }
526    const std::vector<MachineMove> &getInitialFrameState() const {
527      return InitialFrameState;
528    }
529  };
530}
531
532#endif
533