MCAsmInfo.h revision 8ba3f9c9008223136207295b48b53c8aefffa178 
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    /// SeparatorString - This string, if specified, is used to separate
97    /// instructions from each other when on the same line.
98    const char *SeparatorString;             // Defaults to ';'
99
100    /// CommentColumn - This indicates the comment num (zero-based) at
101    /// which asm comments should be printed.
102    unsigned CommentColumn;                  // Defaults to 40
103
104    /// CommentString - This indicates the comment character used by the
105    /// assembler.
106    const char *CommentString;               // Defaults to "#"
107
108    /// LabelSuffix - This is appended to emitted labels.
109    const char *LabelSuffix;                 // Defaults to ":"
110
111    /// LabelSuffix - This is appended to emitted labels.
112    const char *DebugLabelSuffix;                 // 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    /// AllowUTF8 - This is true if the assembler accepts UTF-8 input.
156    // FIXME: Make this a more general encoding setting?
157    bool AllowUTF8;
158
159    /// UseDataRegionDirectives - This is true if data region markers should
160    /// be printed as ".data_region/.end_data_region" directives. If false,
161    /// use "$d/$a" labels instead.
162    bool UseDataRegionDirectives;
163
164    //===--- Data Emission Directives -------------------------------------===//
165
166    /// ZeroDirective - this should be set to the directive used to get some
167    /// number of zero bytes emitted to the current section.  Common cases are
168    /// "\t.zero\t" and "\t.space\t".  If this is set to null, the
169    /// Data*bitsDirective's will be used to emit zero bytes.
170    const char *ZeroDirective;               // Defaults to "\t.zero\t"
171
172    /// AsciiDirective - This directive allows emission of an ascii string with
173    /// the standard C escape characters embedded into it.
174    const char *AsciiDirective;              // Defaults to "\t.ascii\t"
175
176    /// AscizDirective - If not null, this allows for special handling of
177    /// zero terminated strings on this target.  This is commonly supported as
178    /// ".asciz".  If a target doesn't support this, it can be set to null.
179    const char *AscizDirective;              // Defaults to "\t.asciz\t"
180
181    /// DataDirectives - These directives are used to output some unit of
182    /// integer data to the current section.  If a data directive is set to
183    /// null, smaller data directives will be used to emit the large sizes.
184    const char *Data8bitsDirective;          // Defaults to "\t.byte\t"
185    const char *Data16bitsDirective;         // Defaults to "\t.short\t"
186    const char *Data32bitsDirective;         // Defaults to "\t.long\t"
187    const char *Data64bitsDirective;         // Defaults to "\t.quad\t"
188
189    /// GPRel64Directive - if non-null, a directive that is used to emit a word
190    /// which should be relocated as a 64-bit GP-relative offset, e.g. .gpdword
191    /// on Mips.
192    const char *GPRel64Directive;            // Defaults to NULL.
193
194    /// GPRel32Directive - if non-null, a directive that is used to emit a word
195    /// which should be relocated as a 32-bit GP-relative offset, e.g. .gpword
196    /// on Mips or .gprel32 on Alpha.
197    const char *GPRel32Directive;            // Defaults to NULL.
198
199    /// SunStyleELFSectionSwitchSyntax - This is true if this target uses "Sun
200    /// Style" syntax for section switching ("#alloc,#write" etc) instead of the
201    /// normal ELF syntax (,"a,w") in .section directives.
202    bool SunStyleELFSectionSwitchSyntax;     // Defaults to false.
203
204    /// UsesELFSectionDirectiveForBSS - This is true if this target uses ELF
205    /// '.section' directive before the '.bss' one. It's used for PPC/Linux
206    /// which doesn't support the '.bss' directive only.
207    bool UsesELFSectionDirectiveForBSS;      // Defaults to false.
208
209    /// HasMicrosoftFastStdCallMangling - True if this target uses microsoft
210    /// style mangling for functions with X86_StdCall/X86_FastCall calling
211    /// convention.
212    bool HasMicrosoftFastStdCallMangling;    // Defaults to false.
213
214    bool NeedsDwarfSectionOffsetDirective;
215
216    //===--- Alignment Information ----------------------------------------===//
217
218    /// AlignDirective - The directive used to emit round up to an alignment
219    /// boundary.
220    ///
221    const char *AlignDirective;              // Defaults to "\t.align\t"
222
223    /// AlignmentIsInBytes - If this is true (the default) then the asmprinter
224    /// emits ".align N" directives, where N is the number of bytes to align to.
225    /// Otherwise, it emits ".align log2(N)", e.g. 3 to align to an 8 byte
226    /// boundary.
227    bool AlignmentIsInBytes;                 // Defaults to true
228
229    /// TextAlignFillValue - If non-zero, this is used to fill the executable
230    /// space created as the result of a alignment directive.
231    unsigned TextAlignFillValue;             // Defaults to 0
232
233    //===--- Global Variable Emission Directives --------------------------===//
234
235    /// GlobalDirective - This is the directive used to declare a global entity.
236    ///
237    const char *GlobalDirective;             // Defaults to NULL.
238
239    /// ExternDirective - This is the directive used to declare external
240    /// globals.
241    ///
242    const char *ExternDirective;             // Defaults to NULL.
243
244    /// HasSetDirective - True if the assembler supports the .set directive.
245    bool HasSetDirective;                    // Defaults to true.
246
247    /// HasAggressiveSymbolFolding - False if the assembler requires that we use
248    /// Lc = a - b
249    /// .long Lc
250    /// instead of
251    /// .long a - b
252    bool HasAggressiveSymbolFolding;           // Defaults to true.
253
254    /// COMMDirectiveAlignmentIsInBytes - True is .comm's and .lcomms optional
255    /// alignment is to be specified in bytes instead of log2(n).
256    bool COMMDirectiveAlignmentIsInBytes;    // Defaults to true;
257
258    /// LCOMMDirectiveAlignment - Describes if the .lcomm directive for the
259    /// target supports an alignment argument and how it is interpreted.
260    LCOMM::LCOMMType LCOMMDirectiveAlignmentType; // Defaults to NoAlignment.
261
262    /// HasDotTypeDotSizeDirective - True if the target has .type and .size
263    /// directives, this is true for most ELF targets.
264    bool HasDotTypeDotSizeDirective;         // Defaults to true.
265
266    /// HasSingleParameterDotFile - True if the target has a single parameter
267    /// .file directive, this is true for ELF targets.
268    bool HasSingleParameterDotFile;          // Defaults to true.
269
270    /// HasNoDeadStrip - True if this target supports the MachO .no_dead_strip
271    /// directive.
272    bool HasNoDeadStrip;                     // Defaults to false.
273
274    /// HasSymbolResolver - True if this target supports the MachO
275    /// .symbol_resolver directive.
276    bool HasSymbolResolver;                     // Defaults to false.
277
278    /// WeakRefDirective - This directive, if non-null, is used to declare a
279    /// global as being a weak undefined symbol.
280    const char *WeakRefDirective;            // Defaults to NULL.
281
282    /// WeakDefDirective - This directive, if non-null, is used to declare a
283    /// global as being a weak defined symbol.
284    const char *WeakDefDirective;            // Defaults to NULL.
285
286    /// LinkOnceDirective - This directive, if non-null is used to declare a
287    /// global as being a weak defined symbol.  This is used on cygwin/mingw.
288    const char *LinkOnceDirective;           // Defaults to NULL.
289
290    /// HiddenVisibilityAttr - This attribute, if not MCSA_Invalid, is used to
291    /// declare a symbol as having hidden visibility.
292    MCSymbolAttr HiddenVisibilityAttr;       // Defaults to MCSA_Hidden.
293
294    /// HiddenDeclarationVisibilityAttr - This attribute, if not MCSA_Invalid,
295    /// is used to declare an undefined symbol as having hidden visibility.
296    MCSymbolAttr HiddenDeclarationVisibilityAttr;   // Defaults to MCSA_Hidden.
297
298
299    /// ProtectedVisibilityAttr - This attribute, if not MCSA_Invalid, is used
300    /// to declare a symbol as having protected visibility.
301    MCSymbolAttr ProtectedVisibilityAttr;    // Defaults to MCSA_Protected
302
303    //===--- Dwarf Emission Directives -----------------------------------===//
304
305    /// HasLEB128 - True if target asm supports leb128 directives.
306    bool HasLEB128;                          // Defaults to false.
307
308    /// SupportsDebugInformation - True if target supports emission of debugging
309    /// information.
310    bool SupportsDebugInformation;           // Defaults to false.
311
312    /// SupportsExceptionHandling - True if target supports exception handling.
313    ExceptionHandling::ExceptionsType ExceptionsType; // Defaults to None
314
315    /// DwarfUsesRelocationsAcrossSections - True if Dwarf2 output generally
316    /// uses relocations for references to other .debug_* sections.
317    bool DwarfUsesRelocationsAcrossSections;
318
319    /// DwarfRegNumForCFI - True if dwarf register numbers are printed
320    /// instead of symbolic register names in .cfi_* directives.
321    bool DwarfRegNumForCFI;  // Defaults to false;
322
323    //===--- Prologue State ----------------------------------------------===//
324
325    std::vector<MCCFIInstruction> InitialFrameState;
326
327  public:
328    explicit MCAsmInfo();
329    virtual ~MCAsmInfo();
330
331    // FIXME: move these methods to DwarfPrinter when the JIT stops using them.
332    static unsigned getSLEB128Size(int64_t Value);
333    static unsigned getULEB128Size(uint64_t Value);
334
335    /// getPointerSize - Get the pointer size in bytes.
336    unsigned getPointerSize() const {
337      return PointerSize;
338    }
339
340    /// getCalleeSaveStackSlotSize - Get the callee-saved register stack slot
341    /// size in bytes.
342    unsigned getCalleeSaveStackSlotSize() const {
343      return CalleeSaveStackSlotSize;
344    }
345
346    /// isLittleEndian - True if the target is little endian.
347    bool isLittleEndian() const {
348      return IsLittleEndian;
349    }
350
351    /// isStackGrowthDirectionUp - True if target stack grow up.
352    bool isStackGrowthDirectionUp() const {
353      return StackGrowsUp;
354    }
355
356    bool hasSubsectionsViaSymbols() const { return HasSubsectionsViaSymbols; }
357
358    // Data directive accessors.
359    //
360    const char *getData8bitsDirective() const {
361      return Data8bitsDirective;
362    }
363    const char *getData16bitsDirective() const {
364      return Data16bitsDirective;
365    }
366    const char *getData32bitsDirective() const {
367      return Data32bitsDirective;
368    }
369    const char *getData64bitsDirective() const {
370      return Data64bitsDirective;
371    }
372    const char *getGPRel64Directive() const { return GPRel64Directive; }
373    const char *getGPRel32Directive() const { return GPRel32Directive; }
374
375    /// getNonexecutableStackSection - Targets can implement this method to
376    /// specify a section to switch to if the translation unit doesn't have any
377    /// trampolines that require an executable stack.
378    virtual const MCSection *getNonexecutableStackSection(MCContext &Ctx) const{
379      return 0;
380    }
381
382    virtual const MCExpr *
383    getExprForPersonalitySymbol(const MCSymbol *Sym,
384                                unsigned Encoding,
385                                MCStreamer &Streamer) const;
386
387    const MCExpr *
388    getExprForFDESymbol(const MCSymbol *Sym,
389                        unsigned Encoding,
390                        MCStreamer &Streamer) const;
391
392    bool usesSunStyleELFSectionSwitchSyntax() const {
393      return SunStyleELFSectionSwitchSyntax;
394    }
395
396    bool usesELFSectionDirectiveForBSS() const {
397      return UsesELFSectionDirectiveForBSS;
398    }
399
400    bool hasMicrosoftFastStdCallMangling() const {
401      return HasMicrosoftFastStdCallMangling;
402    }
403
404    bool needsDwarfSectionOffsetDirective() const {
405      return NeedsDwarfSectionOffsetDirective;
406    }
407
408    // Accessors.
409    //
410    bool hasMachoZeroFillDirective() const { return HasMachoZeroFillDirective; }
411    bool hasMachoTBSSDirective() const { return HasMachoTBSSDirective; }
412    bool hasStaticCtorDtorReferenceInStaticMode() const {
413      return HasStaticCtorDtorReferenceInStaticMode;
414    }
415    bool getLinkerRequiresNonEmptyDwarfLines() const {
416      return LinkerRequiresNonEmptyDwarfLines;
417    }
418    unsigned getMaxInstLength() const {
419      return MaxInstLength;
420    }
421    unsigned getMinInstAlignment() const {
422      return MinInstAlignment;
423    }
424    const char *getSeparatorString() const {
425      return SeparatorString;
426    }
427    unsigned getCommentColumn() const {
428      return CommentColumn;
429    }
430    const char *getCommentString() const {
431      return CommentString;
432    }
433    const char *getLabelSuffix() const {
434      return LabelSuffix;
435    }
436
437    const char *getDebugLabelSuffix() const {
438      return DebugLabelSuffix;
439    }
440
441    const char *getGlobalPrefix() const {
442      return GlobalPrefix;
443    }
444    const char *getPrivateGlobalPrefix() const {
445      return PrivateGlobalPrefix;
446    }
447    const char *getLinkerPrivateGlobalPrefix() const {
448      return LinkerPrivateGlobalPrefix;
449    }
450    const char *getInlineAsmStart() const {
451      return InlineAsmStart;
452    }
453    const char *getInlineAsmEnd() const {
454      return InlineAsmEnd;
455    }
456    const char *getCode16Directive() const {
457      return Code16Directive;
458    }
459    const char *getCode32Directive() const {
460      return Code32Directive;
461    }
462    const char *getCode64Directive() const {
463      return Code64Directive;
464    }
465    unsigned getAssemblerDialect() const {
466      return AssemblerDialect;
467    }
468    bool doesAllowQuotesInName() const {
469      return AllowQuotesInName;
470    }
471    bool doesAllowNameToStartWithDigit() const {
472      return AllowNameToStartWithDigit;
473    }
474    bool doesAllowPeriodsInName() const {
475      return AllowPeriodsInName;
476    }
477    bool doesAllowUTF8() const {
478      return AllowUTF8;
479    }
480    bool doesSupportDataRegionDirectives() const {
481      return UseDataRegionDirectives;
482    }
483    const char *getZeroDirective() const {
484      return ZeroDirective;
485    }
486    const char *getAsciiDirective() const {
487      return AsciiDirective;
488    }
489    const char *getAscizDirective() const {
490      return AscizDirective;
491    }
492    const char *getAlignDirective() const {
493      return AlignDirective;
494    }
495    bool getAlignmentIsInBytes() const {
496      return AlignmentIsInBytes;
497    }
498    unsigned getTextAlignFillValue() const {
499      return TextAlignFillValue;
500    }
501    const char *getGlobalDirective() const {
502      return GlobalDirective;
503    }
504    const char *getExternDirective() const {
505      return ExternDirective;
506    }
507    bool hasSetDirective() const { return HasSetDirective; }
508    bool hasAggressiveSymbolFolding() const {
509      return HasAggressiveSymbolFolding;
510    }
511    bool getCOMMDirectiveAlignmentIsInBytes() const {
512      return COMMDirectiveAlignmentIsInBytes;
513    }
514    LCOMM::LCOMMType getLCOMMDirectiveAlignmentType() const {
515      return LCOMMDirectiveAlignmentType;
516    }
517    bool hasDotTypeDotSizeDirective() const {return HasDotTypeDotSizeDirective;}
518    bool hasSingleParameterDotFile() const { return HasSingleParameterDotFile; }
519    bool hasNoDeadStrip() const { return HasNoDeadStrip; }
520    bool hasSymbolResolver() const { return HasSymbolResolver; }
521    const char *getWeakRefDirective() const { return WeakRefDirective; }
522    const char *getWeakDefDirective() const { return WeakDefDirective; }
523    const char *getLinkOnceDirective() const { return LinkOnceDirective; }
524
525    MCSymbolAttr getHiddenVisibilityAttr() const { return HiddenVisibilityAttr;}
526    MCSymbolAttr getHiddenDeclarationVisibilityAttr() const {
527      return HiddenDeclarationVisibilityAttr;
528    }
529    MCSymbolAttr getProtectedVisibilityAttr() const {
530      return ProtectedVisibilityAttr;
531    }
532    bool hasLEB128() const {
533      return HasLEB128;
534    }
535    bool doesSupportDebugInformation() const {
536      return SupportsDebugInformation;
537    }
538    bool doesSupportExceptionHandling() const {
539      return ExceptionsType != ExceptionHandling::None;
540    }
541    ExceptionHandling::ExceptionsType getExceptionHandlingType() const {
542      return ExceptionsType;
543    }
544    bool isExceptionHandlingDwarf() const {
545      return
546        (ExceptionsType == ExceptionHandling::DwarfCFI ||
547         ExceptionsType == ExceptionHandling::ARM ||
548         ExceptionsType == ExceptionHandling::Win64);
549    }
550    bool doesDwarfUseRelocationsAcrossSections() const {
551      return DwarfUsesRelocationsAcrossSections;
552    }
553    bool useDwarfRegNumForCFI() const {
554      return DwarfRegNumForCFI;
555    }
556
557    void addInitialFrameState(const MCCFIInstruction &Inst) {
558      InitialFrameState.push_back(Inst);
559    }
560
561    const std::vector<MCCFIInstruction> &getInitialFrameState() const {
562      return InitialFrameState;
563    }
564  };
565}
566
567#endif
568