MCAsmInfo.h revision 56d339f68751aee16c032ed646158b992a200335 
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 <cassert>
20
21namespace llvm {
22  /// MCAsmInfo - This class is intended to be used as a base class for asm
23  /// properties and features specific to the target.
24  namespace ExceptionHandling { enum ExceptionsType { None, Dwarf, SjLj }; }
25
26  class MCAsmInfo {
27  protected:
28    //===------------------------------------------------------------------===//
29    // Properties to be set by the target writer, used to configure asm printer.
30    //
31
32    /// ZeroFillDirective - Directive for emitting a global to the ZeroFill
33    /// section on this target.  Null if this target doesn't support zerofill.
34    const char *ZeroFillDirective;           // Default is null.
35
36    /// NonexecutableStackDirective - Directive for declaring to the
37    /// linker and beyond that the emitted code does not require stack
38    /// memory to be executable.
39    const char *NonexecutableStackDirective; // Default is null.
40
41    /// NeedsSet - True if target asm treats expressions in data directives
42    /// as linktime-relocatable.  For assembly-time computation, we need to
43    /// use a .set.  Thus:
44    /// .set w, x-y
45    /// .long w
46    /// is computed at assembly time, while
47    /// .long x-y
48    /// is relocated if the relative locations of x and y change at linktime.
49    /// We want both these things in different places.
50    bool NeedsSet;                           // Defaults to false.
51
52    /// MaxInstLength - This is the maximum possible length of an instruction,
53    /// which is needed to compute the size of an inline asm.
54    unsigned MaxInstLength;                  // Defaults to 4.
55
56    /// PCSymbol - The symbol used to represent the current PC.  Used in PC
57    /// relative expressions.
58    const char *PCSymbol;                    // Defaults to "$".
59
60    /// SeparatorChar - This character, if specified, is used to separate
61    /// instructions from each other when on the same line.  This is used to
62    /// measure inline asm instructions.
63    char SeparatorChar;                      // Defaults to ';'
64
65    /// CommentColumn - This indicates the comment num (zero-based) at
66    /// which asm comments should be printed.
67    unsigned CommentColumn;                  // Defaults to 60
68
69    /// CommentString - This indicates the comment character used by the
70    /// assembler.
71    const char *CommentString;               // Defaults to "#"
72
73    /// GlobalPrefix - If this is set to a non-empty string, it is prepended
74    /// onto all global symbols.  This is often used for "_" or ".".
75    const char *GlobalPrefix;                // Defaults to ""
76
77    /// PrivateGlobalPrefix - This prefix is used for globals like constant
78    /// pool entries that are completely private to the .s file and should not
79    /// have names in the .o file.  This is often "." or "L".
80    const char *PrivateGlobalPrefix;         // Defaults to "."
81
82    /// LinkerPrivateGlobalPrefix - This prefix is used for symbols that should
83    /// be passed through the assembler but be removed by the linker.  This
84    /// is "l" on Darwin, currently used for some ObjC metadata.
85    const char *LinkerPrivateGlobalPrefix;   // Defaults to ""
86
87    /// GlobalVarAddrPrefix/Suffix - If these are nonempty, these strings
88    /// will enclose any GlobalVariable (that isn't a function)
89    ///
90    const char *GlobalVarAddrPrefix;         // Defaults to ""
91    const char *GlobalVarAddrSuffix;         // Defaults to ""
92
93    /// FunctionAddrPrefix/Suffix - If these are nonempty, these strings
94    /// will enclose any GlobalVariable that points to a function.
95    ///
96    const char *FunctionAddrPrefix;          // Defaults to ""
97    const char *FunctionAddrSuffix;          // Defaults to ""
98
99    /// PersonalityPrefix/Suffix - If these are nonempty, these strings will
100    /// enclose any personality function in the common frame section.
101    ///
102    const char *PersonalityPrefix;           // Defaults to ""
103    const char *PersonalitySuffix;           // Defaults to ""
104
105    /// NeedsIndirectEncoding - If set, we need to set the indirect encoding bit
106    /// for EH in Dwarf.
107    ///
108    bool NeedsIndirectEncoding;              // Defaults to false
109
110    /// InlineAsmStart/End - If these are nonempty, they contain a directive to
111    /// emit before and after an inline assembly statement.
112    const char *InlineAsmStart;              // Defaults to "#APP\n"
113    const char *InlineAsmEnd;                // Defaults to "#NO_APP\n"
114
115    /// AssemblerDialect - Which dialect of an assembler variant to use.
116    unsigned AssemblerDialect;               // Defaults to 0
117
118    /// AllowQuotesInName - This is true if the assembler allows for complex
119    /// symbol names to be surrounded in quotes.  This defaults to false.
120    bool AllowQuotesInName;
121
122    //===--- Data Emission Directives -------------------------------------===//
123
124    /// ZeroDirective - this should be set to the directive used to get some
125    /// number of zero bytes emitted to the current section.  Common cases are
126    /// "\t.zero\t" and "\t.space\t".  If this is set to null, the
127    /// Data*bitsDirective's will be used to emit zero bytes.
128    const char *ZeroDirective;               // Defaults to "\t.zero\t"
129    const char *ZeroDirectiveSuffix;         // Defaults to ""
130
131    /// AsciiDirective - This directive allows emission of an ascii string with
132    /// the standard C escape characters embedded into it.
133    const char *AsciiDirective;              // Defaults to "\t.ascii\t"
134
135    /// AscizDirective - If not null, this allows for special handling of
136    /// zero terminated strings on this target.  This is commonly supported as
137    /// ".asciz".  If a target doesn't support this, it can be set to null.
138    const char *AscizDirective;              // Defaults to "\t.asciz\t"
139
140    /// DataDirectives - These directives are used to output some unit of
141    /// integer data to the current section.  If a data directive is set to
142    /// null, smaller data directives will be used to emit the large sizes.
143    const char *Data8bitsDirective;          // Defaults to "\t.byte\t"
144    const char *Data16bitsDirective;         // Defaults to "\t.short\t"
145    const char *Data32bitsDirective;         // Defaults to "\t.long\t"
146    const char *Data64bitsDirective;         // Defaults to "\t.quad\t"
147
148    /// getDataASDirective - Return the directive that should be used to emit
149    /// data of the specified size to the specified numeric address space.
150    virtual const char *getDataASDirective(unsigned Size, unsigned AS) const {
151      assert(AS != 0 && "Don't know the directives for default addr space");
152      return 0;
153    }
154
155    /// SunStyleELFSectionSwitchSyntax - This is true if this target uses "Sun
156    /// Style" syntax for section switching ("#alloc,#write" etc) instead of the
157    /// normal ELF syntax (,"a,w") in .section directives.
158    bool SunStyleELFSectionSwitchSyntax;     // Defaults to false.
159
160    /// UsesELFSectionDirectiveForBSS - This is true if this target uses ELF
161    /// '.section' directive before the '.bss' one. It's used for PPC/Linux
162    /// which doesn't support the '.bss' directive only.
163    bool UsesELFSectionDirectiveForBSS;      // Defaults to false.
164
165    //===--- Alignment Information ----------------------------------------===//
166
167    /// AlignDirective - The directive used to emit round up to an alignment
168    /// boundary.
169    ///
170    const char *AlignDirective;              // Defaults to "\t.align\t"
171
172    /// AlignmentIsInBytes - If this is true (the default) then the asmprinter
173    /// emits ".align N" directives, where N is the number of bytes to align to.
174    /// Otherwise, it emits ".align log2(N)", e.g. 3 to align to an 8 byte
175    /// boundary.
176    bool AlignmentIsInBytes;                 // Defaults to true
177
178    /// TextAlignFillValue - If non-zero, this is used to fill the executable
179    /// space created as the result of a alignment directive.
180    unsigned TextAlignFillValue;             // Defaults to 0
181
182    //===--- Section Switching Directives ---------------------------------===//
183
184    /// JumpTableDirective - if non-null, the directive to emit before jump
185    /// table entries.  FIXME: REMOVE THIS.
186    const char *JumpTableDirective;          // Defaults to NULL.
187    const char *PICJumpTableDirective;       // Defaults to NULL.
188
189
190    //===--- Global Variable Emission Directives --------------------------===//
191
192    /// GlobalDirective - This is the directive used to declare a global entity.
193    ///
194    const char *GlobalDirective;             // Defaults to NULL.
195
196    /// ExternDirective - This is the directive used to declare external
197    /// globals.
198    ///
199    const char *ExternDirective;             // Defaults to NULL.
200
201    /// SetDirective - This is the name of a directive that can be used to tell
202    /// the assembler to set the value of a variable to some expression.
203    const char *SetDirective;                // Defaults to null.
204
205    /// LCOMMDirective - This is the name of a directive (if supported) that can
206    /// be used to efficiently declare a local (internal) block of zero
207    /// initialized data in the .bss/.data section.  The syntax expected is:
208    /// @verbatim <LCOMMDirective> SYMBOLNAME LENGTHINBYTES, ALIGNMENT
209    /// @endverbatim
210    const char *LCOMMDirective;              // Defaults to null.
211
212    const char *COMMDirective;               // Defaults to "\t.comm\t".
213
214    /// COMMDirectiveTakesAlignment - True if COMMDirective take a third
215    /// argument that specifies the alignment of the declaration.
216    bool COMMDirectiveTakesAlignment;        // Defaults to true.
217
218    /// HasDotTypeDotSizeDirective - True if the target has .type and .size
219    /// directives, this is true for most ELF targets.
220    bool HasDotTypeDotSizeDirective;         // Defaults to true.
221
222    /// HasSingleParameterDotFile - True if the target has a single parameter
223    /// .file directive, this is true for ELF targets.
224    bool HasSingleParameterDotFile;          // Defaults to true.
225
226    /// UsedDirective - This directive, if non-null, is used to declare a global
227    /// as being used somehow that the assembler can't see.  This prevents dead
228    /// code elimination on some targets.
229    const char *UsedDirective;               // Defaults to NULL.
230
231    /// WeakRefDirective - This directive, if non-null, is used to declare a
232    /// global as being a weak undefined symbol.
233    const char *WeakRefDirective;            // Defaults to NULL.
234
235    /// WeakDefDirective - This directive, if non-null, is used to declare a
236    /// global as being a weak defined symbol.
237    const char *WeakDefDirective;            // Defaults to NULL.
238
239    /// HiddenDirective - This directive, if non-null, is used to declare a
240    /// global or function as having hidden visibility.
241    const char *HiddenDirective;             // Defaults to "\t.hidden\t".
242
243    /// ProtectedDirective - This directive, if non-null, is used to declare a
244    /// global or function as having protected visibility.
245    const char *ProtectedDirective;          // Defaults to "\t.protected\t".
246
247    //===--- Dwarf Emission Directives -----------------------------------===//
248
249    /// AbsoluteDebugSectionOffsets - True if we should emit abolute section
250    /// offsets for debug information.
251    bool AbsoluteDebugSectionOffsets;        // Defaults to false.
252
253    /// AbsoluteEHSectionOffsets - True if we should emit abolute section
254    /// offsets for EH information. Defaults to false.
255    bool AbsoluteEHSectionOffsets;
256
257    /// HasLEB128 - True if target asm supports leb128 directives.
258    bool HasLEB128;                          // Defaults to false.
259
260    /// hasDotLocAndDotFile - True if target asm supports .loc and .file
261    /// directives for emitting debugging information.
262    bool HasDotLocAndDotFile;                // Defaults to false.
263
264    /// SupportsDebugInformation - True if target supports emission of debugging
265    /// information.
266    bool SupportsDebugInformation;           // Defaults to false.
267
268    /// SupportsExceptionHandling - True if target supports exception handling.
269    ExceptionHandling::ExceptionsType ExceptionsType; // Defaults to None
270
271    /// RequiresFrameSection - true if the Dwarf2 output needs a frame section
272    bool DwarfRequiresFrameSection;          // Defaults to true.
273
274    /// DwarfUsesInlineInfoSection - True if DwarfDebugInlineSection is used to
275    /// encode inline subroutine information.
276    bool DwarfUsesInlineInfoSection;         // Defaults to false.
277
278    /// Is_EHSymbolPrivate - If set, the "_foo.eh" is made private so that it
279    /// doesn't show up in the symbol table of the object file.
280    bool Is_EHSymbolPrivate;                 // Defaults to true.
281
282    /// GlobalEHDirective - This is the directive used to make exception frame
283    /// tables globally visible.
284    const char *GlobalEHDirective;           // Defaults to NULL.
285
286    /// SupportsWeakEmptyEHFrame - True if target assembler and linker will
287    /// handle a weak_definition of constant 0 for an omitted EH frame.
288    bool SupportsWeakOmittedEHFrame;         // Defaults to true.
289
290    /// DwarfSectionOffsetDirective - Special section offset directive.
291    const char* DwarfSectionOffsetDirective; // Defaults to NULL
292
293    //===--- CBE Asm Translation Table -----------------------------------===//
294
295    const char *const *AsmTransCBE;          // Defaults to empty
296
297  public:
298    explicit MCAsmInfo();
299    virtual ~MCAsmInfo();
300
301    /// getSLEB128Size - Compute the number of bytes required for a signed
302    /// leb128 value.
303    static unsigned getSLEB128Size(int Value);
304
305    /// getULEB128Size - Compute the number of bytes required for an unsigned
306    /// leb128 value.
307    static unsigned getULEB128Size(unsigned Value);
308
309    // Data directive accessors.
310    //
311    const char *getData8bitsDirective(unsigned AS = 0) const {
312      return AS == 0 ? Data8bitsDirective : getDataASDirective(8, AS);
313    }
314    const char *getData16bitsDirective(unsigned AS = 0) const {
315      return AS == 0 ? Data16bitsDirective : getDataASDirective(16, AS);
316    }
317    const char *getData32bitsDirective(unsigned AS = 0) const {
318      return AS == 0 ? Data32bitsDirective : getDataASDirective(32, AS);
319    }
320    const char *getData64bitsDirective(unsigned AS = 0) const {
321      return AS == 0 ? Data64bitsDirective : getDataASDirective(64, AS);
322    }
323
324
325    bool usesSunStyleELFSectionSwitchSyntax() const {
326      return SunStyleELFSectionSwitchSyntax;
327    }
328
329    bool usesELFSectionDirectiveForBSS() const {
330      return UsesELFSectionDirectiveForBSS;
331    }
332
333    // Accessors.
334    //
335    const char *getZeroFillDirective() const {
336      return ZeroFillDirective;
337    }
338    const char *getNonexecutableStackDirective() const {
339      return NonexecutableStackDirective;
340    }
341    bool needsSet() const {
342      return NeedsSet;
343    }
344    unsigned getMaxInstLength() const {
345      return MaxInstLength;
346    }
347    const char *getPCSymbol() const {
348      return PCSymbol;
349    }
350    char getSeparatorChar() const {
351      return SeparatorChar;
352    }
353    unsigned getCommentColumn() const {
354      return CommentColumn;
355    }
356    const char *getCommentString() const {
357      return CommentString;
358    }
359    const char *getGlobalPrefix() const {
360      return GlobalPrefix;
361    }
362    const char *getPrivateGlobalPrefix() const {
363      return PrivateGlobalPrefix;
364    }
365    const char *getLinkerPrivateGlobalPrefix() const {
366      return LinkerPrivateGlobalPrefix;
367    }
368    const char *getGlobalVarAddrPrefix() const {
369      return GlobalVarAddrPrefix;
370    }
371    const char *getGlobalVarAddrSuffix() const {
372      return GlobalVarAddrSuffix;
373    }
374    const char *getFunctionAddrPrefix() const {
375      return FunctionAddrPrefix;
376    }
377    const char *getFunctionAddrSuffix() const {
378      return FunctionAddrSuffix;
379    }
380    const char *getPersonalityPrefix() const {
381      return PersonalityPrefix;
382    }
383    const char *getPersonalitySuffix() const {
384      return PersonalitySuffix;
385    }
386    bool getNeedsIndirectEncoding() const {
387      return NeedsIndirectEncoding;
388    }
389    const char *getInlineAsmStart() const {
390      return InlineAsmStart;
391    }
392    const char *getInlineAsmEnd() const {
393      return InlineAsmEnd;
394    }
395    unsigned getAssemblerDialect() const {
396      return AssemblerDialect;
397    }
398    bool doesAllowQuotesInName() const {
399      return AllowQuotesInName;
400    }
401    const char *getZeroDirective() const {
402      return ZeroDirective;
403    }
404    const char *getZeroDirectiveSuffix() const {
405      return ZeroDirectiveSuffix;
406    }
407    const char *getAsciiDirective() const {
408      return AsciiDirective;
409    }
410    const char *getAscizDirective() const {
411      return AscizDirective;
412    }
413    const char *getJumpTableDirective(bool isPIC) const {
414      return isPIC ? PICJumpTableDirective : JumpTableDirective;
415    }
416    const char *getAlignDirective() const {
417      return AlignDirective;
418    }
419    bool getAlignmentIsInBytes() const {
420      return AlignmentIsInBytes;
421    }
422    unsigned getTextAlignFillValue() const {
423      return TextAlignFillValue;
424    }
425    const char *getGlobalDirective() const {
426      return GlobalDirective;
427    }
428    const char *getExternDirective() const {
429      return ExternDirective;
430    }
431    const char *getSetDirective() const {
432      return SetDirective;
433    }
434    const char *getLCOMMDirective() const {
435      return LCOMMDirective;
436    }
437    const char *getCOMMDirective() const {
438      return COMMDirective;
439    }
440    bool getCOMMDirectiveTakesAlignment() const {
441      return COMMDirectiveTakesAlignment;
442    }
443    bool hasDotTypeDotSizeDirective() const {
444      return HasDotTypeDotSizeDirective;
445    }
446    bool hasSingleParameterDotFile() const {
447      return HasSingleParameterDotFile;
448    }
449    const char *getUsedDirective() const {
450      return UsedDirective;
451    }
452    const char *getWeakRefDirective() const {
453      return WeakRefDirective;
454    }
455    const char *getWeakDefDirective() const {
456      return WeakDefDirective;
457    }
458    const char *getHiddenDirective() const {
459      return HiddenDirective;
460    }
461    const char *getProtectedDirective() const {
462      return ProtectedDirective;
463    }
464    bool isAbsoluteDebugSectionOffsets() const {
465      return AbsoluteDebugSectionOffsets;
466    }
467    bool isAbsoluteEHSectionOffsets() const {
468      return AbsoluteEHSectionOffsets;
469    }
470    bool hasLEB128() const {
471      return HasLEB128;
472    }
473    bool hasDotLocAndDotFile() const {
474      return HasDotLocAndDotFile;
475    }
476    bool doesSupportDebugInformation() const {
477      return SupportsDebugInformation;
478    }
479    bool doesSupportExceptionHandling() const {
480      return ExceptionsType != ExceptionHandling::None;
481    }
482    ExceptionHandling::ExceptionsType getExceptionHandlingType() const {
483      return ExceptionsType;
484    }
485    bool doesDwarfRequireFrameSection() const {
486      return DwarfRequiresFrameSection;
487    }
488    bool doesDwarfUsesInlineInfoSection() const {
489      return DwarfUsesInlineInfoSection;
490    }
491    bool is_EHSymbolPrivate() const {
492      return Is_EHSymbolPrivate;
493    }
494    const char *getGlobalEHDirective() const {
495      return GlobalEHDirective;
496    }
497    bool getSupportsWeakOmittedEHFrame() const {
498      return SupportsWeakOmittedEHFrame;
499    }
500    const char *getDwarfSectionOffsetDirective() const {
501      return DwarfSectionOffsetDirective;
502    }
503    const char *const *getAsmCBE() const {
504      return AsmTransCBE;
505    }
506  };
507}
508
509#endif
510