MCAsmInfo.h revision 5ec2e6b586bf4029763711d6860b57d312eb2d2e 
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/Support/DataTypes.h"
20#include <cassert>
21
22namespace llvm {
23  template <typename T> class SmallVectorImpl;
24
25  /// MCAsmInfo - This class is intended to be used as a base class for asm
26  /// properties and features specific to the target.
27  namespace ExceptionHandling { enum ExceptionsType { None, Dwarf, SjLj }; }
28
29  class MCAsmInfo {
30  protected:
31    //===------------------------------------------------------------------===//
32    // Properties to be set by the target writer, used to configure asm printer.
33    //
34
35    /// ZeroFillDirective - Directive for emitting a global to the ZeroFill
36    /// section on this target.  Null if this target doesn't support zerofill.
37    const char *ZeroFillDirective;        // Default is null.
38
39    /// NonexecutableStackDirective - Directive for declaring to the
40    /// linker and beyond that the emitted code does not require stack
41    /// memory to be executable.
42    const char *NonexecutableStackDirective; // Default is null.
43
44    /// NeedsSet - True if target asm treats expressions in data directives
45    /// as linktime-relocatable.  For assembly-time computation, we need to
46    /// use a .set.  Thus:
47    /// .set w, x-y
48    /// .long w
49    /// is computed at assembly time, while
50    /// .long x-y
51    /// is relocated if the relative locations of x and y change at linktime.
52    /// We want both these things in different places.
53    bool NeedsSet;                        // Defaults to false.
54
55    /// MaxInstLength - This is the maximum possible length of an instruction,
56    /// which is needed to compute the size of an inline asm.
57    unsigned MaxInstLength;               // Defaults to 4.
58
59    /// PCSymbol - The symbol used to represent the current PC.  Used in PC
60    /// relative expressions.
61    const char *PCSymbol;                 // Defaults to "$".
62
63    /// SeparatorChar - This character, if specified, is used to separate
64    /// instructions from each other when on the same line.  This is used to
65    /// measure inline asm instructions.
66    char SeparatorChar;                   // Defaults to ';'
67
68    /// CommentColumn - This indicates the comment num (zero-based) at
69    /// which asm comments should be printed.
70    unsigned CommentColumn;               // Defaults to 60
71
72    /// CommentString - This indicates the comment character used by the
73    /// assembler.
74    const char *CommentString;            // Defaults to "#"
75
76    /// GlobalPrefix - If this is set to a non-empty string, it is prepended
77    /// onto all global symbols.  This is often used for "_" or ".".
78    const char *GlobalPrefix;             // Defaults to ""
79
80    /// PrivateGlobalPrefix - This prefix is used for globals like constant
81    /// pool entries that are completely private to the .s file and should not
82    /// have names in the .o file.  This is often "." or "L".
83    const char *PrivateGlobalPrefix;      // Defaults to "."
84
85    /// LinkerPrivateGlobalPrefix - This prefix is used for symbols that should
86    /// be passed through the assembler but be removed by the linker.  This
87    /// is "l" on Darwin, currently used for some ObjC metadata.
88    const char *LinkerPrivateGlobalPrefix;      // Defaults to ""
89
90    /// JumpTableSpecialLabelPrefix - If not null, a extra (dead) label is
91    /// emitted before jump tables with the specified prefix.
92    const char *JumpTableSpecialLabelPrefix;  // Default to null.
93
94    /// GlobalVarAddrPrefix/Suffix - If these are nonempty, these strings
95    /// will enclose any GlobalVariable (that isn't a function)
96    ///
97    const char *GlobalVarAddrPrefix;      // Defaults to ""
98    const char *GlobalVarAddrSuffix;      // Defaults to ""
99
100    /// FunctionAddrPrefix/Suffix - If these are nonempty, these strings
101    /// will enclose any GlobalVariable that points to a function.
102    ///
103    const char *FunctionAddrPrefix;       // Defaults to ""
104    const char *FunctionAddrSuffix;       // Defaults to ""
105
106    /// PersonalityPrefix/Suffix - If these are nonempty, these strings will
107    /// enclose any personality function in the common frame section.
108    ///
109    const char *PersonalityPrefix;        // Defaults to ""
110    const char *PersonalitySuffix;        // Defaults to ""
111
112    /// NeedsIndirectEncoding - If set, we need to set the indirect encoding bit
113    /// for EH in Dwarf.
114    ///
115    bool NeedsIndirectEncoding;           // Defaults to false
116
117    /// InlineAsmStart/End - If these are nonempty, they contain a directive to
118    /// emit before and after an inline assembly statement.
119    const char *InlineAsmStart;           // Defaults to "#APP\n"
120    const char *InlineAsmEnd;             // Defaults to "#NO_APP\n"
121
122    /// AssemblerDialect - Which dialect of an assembler variant to use.
123    unsigned AssemblerDialect;            // Defaults to 0
124
125    /// AllowQuotesInName - This is true if the assembler allows for complex
126    /// symbol names to be surrounded in quotes.  This defaults to false.
127    bool AllowQuotesInName;
128
129    //===--- Data Emission Directives -------------------------------------===//
130
131    /// ZeroDirective - this should be set to the directive used to get some
132    /// number of zero bytes emitted to the current section.  Common cases are
133    /// "\t.zero\t" and "\t.space\t".  If this is set to null, the
134    /// Data*bitsDirective's will be used to emit zero bytes.
135    const char *ZeroDirective;            // Defaults to "\t.zero\t"
136    const char *ZeroDirectiveSuffix;      // Defaults to ""
137
138    /// AsciiDirective - This directive allows emission of an ascii string with
139    /// the standard C escape characters embedded into it.
140    const char *AsciiDirective;           // Defaults to "\t.ascii\t"
141
142    /// AscizDirective - If not null, this allows for special handling of
143    /// zero terminated strings on this target.  This is commonly supported as
144    /// ".asciz".  If a target doesn't support this, it can be set to null.
145    const char *AscizDirective;           // Defaults to "\t.asciz\t"
146
147    /// DataDirectives - These directives are used to output some unit of
148    /// integer data to the current section.  If a data directive is set to
149    /// null, smaller data directives will be used to emit the large sizes.
150    const char *Data8bitsDirective;       // Defaults to "\t.byte\t"
151    const char *Data16bitsDirective;      // Defaults to "\t.short\t"
152    const char *Data32bitsDirective;      // Defaults to "\t.long\t"
153    const char *Data64bitsDirective;      // Defaults to "\t.quad\t"
154
155    /// getDataASDirective - Return the directive that should be used to emit
156    /// data of the specified size to the specified numeric address space.
157    virtual const char *getDataASDirective(unsigned Size, unsigned AS) const {
158      assert(AS != 0 && "Don't know the directives for default addr space");
159      return 0;
160    }
161
162    /// SunStyleELFSectionSwitchSyntax - This is true if this target uses "Sun
163    /// Style" syntax for section switching ("#alloc,#write" etc) instead of the
164    /// normal ELF syntax (,"a,w") in .section directives.
165    bool SunStyleELFSectionSwitchSyntax;   // Defaults to false.
166
167    /// UsesELFSectionDirectiveForBSS - This is true if this target uses ELF
168    /// '.section' directive before the '.bss' one. It's used for PPC/Linux
169    /// which doesn't support the '.bss' directive only.
170    bool UsesELFSectionDirectiveForBSS;  // Defaults to false.
171
172    //===--- Alignment Information ----------------------------------------===//
173
174    /// AlignDirective - The directive used to emit round up to an alignment
175    /// boundary.
176    ///
177    const char *AlignDirective;           // Defaults to "\t.align\t"
178
179    /// AlignmentIsInBytes - If this is true (the default) then the asmprinter
180    /// emits ".align N" directives, where N is the number of bytes to align to.
181    /// Otherwise, it emits ".align log2(N)", e.g. 3 to align to an 8 byte
182    /// boundary.
183    bool AlignmentIsInBytes;              // Defaults to true
184
185    /// TextAlignFillValue - If non-zero, this is used to fill the executable
186    /// space created as the result of a alignment directive.
187    unsigned TextAlignFillValue;
188
189    //===--- Section Switching Directives ---------------------------------===//
190
191    /// JumpTableDirective - if non-null, the directive to emit before jump
192    /// table entries.  FIXME: REMOVE THIS.
193    const char *JumpTableDirective;
194    const char *PICJumpTableDirective;
195
196
197    //===--- Global Variable Emission Directives --------------------------===//
198
199    /// GlobalDirective - This is the directive used to declare a global entity.
200    ///
201    const char *GlobalDirective;          // Defaults to NULL.
202
203    /// ExternDirective - This is the directive used to declare external
204    /// globals.
205    ///
206    const char *ExternDirective;          // Defaults to NULL.
207
208    /// SetDirective - This is the name of a directive that can be used to tell
209    /// the assembler to set the value of a variable to some expression.
210    const char *SetDirective;             // Defaults to null.
211
212    /// LCOMMDirective - This is the name of a directive (if supported) that can
213    /// be used to efficiently declare a local (internal) block of zero
214    /// initialized data in the .bss/.data section.  The syntax expected is:
215    /// @verbatim <LCOMMDirective> SYMBOLNAME LENGTHINBYTES, ALIGNMENT
216    /// @endverbatim
217    const char *LCOMMDirective;           // Defaults to null.
218
219    const char *COMMDirective;            // Defaults to "\t.comm\t".
220
221    /// COMMDirectiveTakesAlignment - True if COMMDirective take a third
222    /// argument that specifies the alignment of the declaration.
223    bool COMMDirectiveTakesAlignment;     // Defaults to true.
224
225    /// HasDotTypeDotSizeDirective - True if the target has .type and .size
226    /// directives, this is true for most ELF targets.
227    bool HasDotTypeDotSizeDirective;      // Defaults to true.
228
229    /// HasSingleParameterDotFile - True if the target has a single parameter
230    /// .file directive, this is true for ELF targets.
231    bool HasSingleParameterDotFile;      // Defaults to true.
232
233    /// UsedDirective - This directive, if non-null, is used to declare a global
234    /// as being used somehow that the assembler can't see.  This prevents dead
235    /// code elimination on some targets.
236    const char *UsedDirective;            // Defaults to null.
237
238    /// WeakRefDirective - This directive, if non-null, is used to declare a
239    /// global as being a weak undefined symbol.
240    const char *WeakRefDirective;         // Defaults to null.
241
242    /// WeakDefDirective - This directive, if non-null, is used to declare a
243    /// global as being a weak defined symbol.
244    const char *WeakDefDirective;         // Defaults to null.
245
246    /// HiddenDirective - This directive, if non-null, is used to declare a
247    /// global or function as having hidden visibility.
248    const char *HiddenDirective;          // Defaults to "\t.hidden\t".
249
250    /// ProtectedDirective - This directive, if non-null, is used to declare a
251    /// global or function as having protected visibility.
252    const char *ProtectedDirective;       // Defaults to "\t.protected\t".
253
254    //===--- Dwarf Emission Directives -----------------------------------===//
255
256    /// AbsoluteDebugSectionOffsets - True if we should emit abolute section
257    /// offsets for debug information. Defaults to false.
258    bool AbsoluteDebugSectionOffsets;
259
260    /// AbsoluteEHSectionOffsets - True if we should emit abolute section
261    /// offsets for EH information. Defaults to false.
262    bool AbsoluteEHSectionOffsets;
263
264    /// HasLEB128 - True if target asm supports leb128 directives.
265    ///
266    bool HasLEB128; // Defaults to false.
267
268    /// hasDotLocAndDotFile - True if target asm supports .loc and .file
269    /// directives for emitting debugging information.
270    ///
271    bool HasDotLocAndDotFile; // Defaults to false.
272
273    /// SupportsDebugInformation - True if target supports emission of debugging
274    /// information.
275    bool SupportsDebugInformation;
276
277    /// SupportsExceptionHandling - True if target supports
278    /// exception handling.
279    ///
280    // Defaults to None
281    ExceptionHandling::ExceptionsType ExceptionsType;
282
283    /// RequiresFrameSection - true if the Dwarf2 output needs a frame section
284    ///
285    bool DwarfRequiresFrameSection; // Defaults to true.
286
287    /// DwarfUsesInlineInfoSection - True if DwarfDebugInlineSection is used to
288    /// encode inline subroutine information.
289    bool DwarfUsesInlineInfoSection; // Defaults to false.
290
291    /// Is_EHSymbolPrivate - If set, the "_foo.eh" is made private so that it
292    /// doesn't show up in the symbol table of the object file.
293    bool Is_EHSymbolPrivate;                // Defaults to true.
294
295    /// GlobalEHDirective - This is the directive used to make exception frame
296    /// tables globally visible.
297    ///
298    const char *GlobalEHDirective;          // Defaults to NULL.
299
300    /// SupportsWeakEmptyEHFrame - True if target assembler and linker will
301    /// handle a weak_definition of constant 0 for an omitted EH frame.
302    bool SupportsWeakOmittedEHFrame;  // Defaults to true.
303
304    /// DwarfSectionOffsetDirective - Special section offset directive.
305    const char* DwarfSectionOffsetDirective; // Defaults to NULL
306
307    //===--- CBE Asm Translation Table -----------------------------------===//
308
309    const char *const *AsmTransCBE; // Defaults to empty
310
311  public:
312    explicit MCAsmInfo();
313    virtual ~MCAsmInfo();
314
315    /// getSLEB128Size - Compute the number of bytes required for a signed
316    /// leb128 value.
317    static unsigned getSLEB128Size(int Value);
318
319    /// getULEB128Size - Compute the number of bytes required for an unsigned
320    /// leb128 value.
321    static unsigned getULEB128Size(unsigned Value);
322
323    // Data directive accessors.
324    //
325    const char *getData8bitsDirective(unsigned AS = 0) const {
326      return AS == 0 ? Data8bitsDirective : getDataASDirective(8, AS);
327    }
328    const char *getData16bitsDirective(unsigned AS = 0) const {
329      return AS == 0 ? Data16bitsDirective : getDataASDirective(16, AS);
330    }
331    const char *getData32bitsDirective(unsigned AS = 0) const {
332      return AS == 0 ? Data32bitsDirective : getDataASDirective(32, AS);
333    }
334    const char *getData64bitsDirective(unsigned AS = 0) const {
335      return AS == 0 ? Data64bitsDirective : getDataASDirective(64, AS);
336    }
337
338
339    bool usesSunStyleELFSectionSwitchSyntax() const {
340      return SunStyleELFSectionSwitchSyntax;
341    }
342
343    bool usesELFSectionDirectiveForBSS() const {
344      return UsesELFSectionDirectiveForBSS;
345    }
346
347    // Accessors.
348    //
349    const char *getZeroFillDirective() const {
350      return ZeroFillDirective;
351    }
352    const char *getNonexecutableStackDirective() const {
353      return NonexecutableStackDirective;
354    }
355    bool needsSet() const {
356      return NeedsSet;
357    }
358    unsigned getMaxInstLength() const {
359      return MaxInstLength;
360    }
361    const char *getPCSymbol() const {
362      return PCSymbol;
363    }
364    char getSeparatorChar() const {
365      return SeparatorChar;
366    }
367    unsigned getCommentColumn() const {
368      return CommentColumn;
369    }
370    const char *getCommentString() const {
371      return CommentString;
372    }
373    const char *getGlobalPrefix() const {
374      return GlobalPrefix;
375    }
376    const char *getPrivateGlobalPrefix() const {
377      return PrivateGlobalPrefix;
378    }
379    const char *getLinkerPrivateGlobalPrefix() const {
380      return LinkerPrivateGlobalPrefix;
381    }
382    const char *getJumpTableSpecialLabelPrefix() const {
383      return JumpTableSpecialLabelPrefix;
384    }
385    const char *getGlobalVarAddrPrefix() const {
386      return GlobalVarAddrPrefix;
387    }
388    const char *getGlobalVarAddrSuffix() const {
389      return GlobalVarAddrSuffix;
390    }
391    const char *getFunctionAddrPrefix() const {
392      return FunctionAddrPrefix;
393    }
394    const char *getFunctionAddrSuffix() const {
395      return FunctionAddrSuffix;
396    }
397    const char *getPersonalityPrefix() const {
398      return PersonalityPrefix;
399    }
400    const char *getPersonalitySuffix() const {
401      return PersonalitySuffix;
402    }
403    bool getNeedsIndirectEncoding() const {
404      return NeedsIndirectEncoding;
405    }
406    const char *getInlineAsmStart() const {
407      return InlineAsmStart;
408    }
409    const char *getInlineAsmEnd() const {
410      return InlineAsmEnd;
411    }
412    unsigned getAssemblerDialect() const {
413      return AssemblerDialect;
414    }
415    bool doesAllowQuotesInName() const {
416      return AllowQuotesInName;
417    }
418    const char *getZeroDirective() const {
419      return ZeroDirective;
420    }
421    const char *getZeroDirectiveSuffix() const {
422      return ZeroDirectiveSuffix;
423    }
424    const char *getAsciiDirective() const {
425      return AsciiDirective;
426    }
427    const char *getAscizDirective() const {
428      return AscizDirective;
429    }
430    const char *getJumpTableDirective(bool isPIC) const {
431      return isPIC ? PICJumpTableDirective : JumpTableDirective;
432    }
433    const char *getAlignDirective() const {
434      return AlignDirective;
435    }
436    bool getAlignmentIsInBytes() const {
437      return AlignmentIsInBytes;
438    }
439    unsigned getTextAlignFillValue() const {
440      return TextAlignFillValue;
441    }
442    const char *getGlobalDirective() const {
443      return GlobalDirective;
444    }
445    const char *getExternDirective() const {
446      return ExternDirective;
447    }
448    const char *getSetDirective() const {
449      return SetDirective;
450    }
451    const char *getLCOMMDirective() const {
452      return LCOMMDirective;
453    }
454    const char *getCOMMDirective() const {
455      return COMMDirective;
456    }
457    bool getCOMMDirectiveTakesAlignment() const {
458      return COMMDirectiveTakesAlignment;
459    }
460    bool hasDotTypeDotSizeDirective() const {
461      return HasDotTypeDotSizeDirective;
462    }
463    bool hasSingleParameterDotFile() const {
464      return HasSingleParameterDotFile;
465    }
466    const char *getUsedDirective() const {
467      return UsedDirective;
468    }
469    const char *getWeakRefDirective() const {
470      return WeakRefDirective;
471    }
472    const char *getWeakDefDirective() const {
473      return WeakDefDirective;
474    }
475    const char *getHiddenDirective() const {
476      return HiddenDirective;
477    }
478    const char *getProtectedDirective() const {
479      return ProtectedDirective;
480    }
481    bool isAbsoluteDebugSectionOffsets() const {
482      return AbsoluteDebugSectionOffsets;
483    }
484    bool isAbsoluteEHSectionOffsets() const {
485      return AbsoluteEHSectionOffsets;
486    }
487    bool hasLEB128() const {
488      return HasLEB128;
489    }
490    bool hasDotLocAndDotFile() const {
491      return HasDotLocAndDotFile;
492    }
493    bool doesSupportDebugInformation() const {
494      return SupportsDebugInformation;
495    }
496    bool doesSupportExceptionHandling() const {
497      return ExceptionsType != ExceptionHandling::None;
498    }
499    ExceptionHandling::ExceptionsType getExceptionHandlingType() const {
500      return ExceptionsType;
501    }
502    bool doesDwarfRequireFrameSection() const {
503      return DwarfRequiresFrameSection;
504    }
505    bool doesDwarfUsesInlineInfoSection() const {
506      return DwarfUsesInlineInfoSection;
507    }
508    bool is_EHSymbolPrivate() const {
509      return Is_EHSymbolPrivate;
510    }
511    const char *getGlobalEHDirective() const {
512      return GlobalEHDirective;
513    }
514    bool getSupportsWeakOmittedEHFrame() const {
515      return SupportsWeakOmittedEHFrame;
516    }
517    const char *getDwarfSectionOffsetDirective() const {
518      return DwarfSectionOffsetDirective;
519    }
520    const char *const *getAsmCBE() const {
521      return AsmTransCBE;
522    }
523  };
524}
525
526#endif
527