MCAsmInfo.h revision 82d748d55c549dd055528ed10dbb534618ca8115 
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#include <string>
22
23namespace llvm {
24  template <typename T> class SmallVectorImpl;
25
26  /// MCAsmInfo - This class is intended to be used as a base class for asm
27  /// properties and features specific to the target.
28  namespace ExceptionHandling { enum ExceptionsType { None, Dwarf, SjLj }; }
29
30  class MCAsmInfo {
31  protected:
32    //===------------------------------------------------------------------===//
33    // Properties to be set by the target writer, used to configure asm printer.
34    //
35
36    /// ZeroFillDirective - Directive for emitting a global to the ZeroFill
37    /// section on this target.  Null if this target doesn't support zerofill.
38    const char *ZeroFillDirective;        // Default is null.
39
40    /// NonexecutableStackDirective - Directive for declaring to the
41    /// linker and beyond that the emitted code does not require stack
42    /// memory to be executable.
43    const char *NonexecutableStackDirective; // Default is null.
44
45    /// NeedsSet - True if target asm treats expressions in data directives
46    /// as linktime-relocatable.  For assembly-time computation, we need to
47    /// use a .set.  Thus:
48    /// .set w, x-y
49    /// .long w
50    /// is computed at assembly time, while
51    /// .long x-y
52    /// is relocated if the relative locations of x and y change at linktime.
53    /// We want both these things in different places.
54    bool NeedsSet;                        // Defaults to false.
55
56    /// MaxInstLength - This is the maximum possible length of an instruction,
57    /// which is needed to compute the size of an inline asm.
58    unsigned MaxInstLength;               // Defaults to 4.
59
60    /// PCSymbol - The symbol used to represent the current PC.  Used in PC
61    /// relative expressions.
62    const char *PCSymbol;                 // Defaults to "$".
63
64    /// SeparatorChar - This character, if specified, is used to separate
65    /// instructions from each other when on the same line.  This is used to
66    /// measure inline asm instructions.
67    char SeparatorChar;                   // Defaults to ';'
68
69    /// CommentColumn - This indicates the comment num (zero-based) at
70    /// which asm comments should be printed.
71    unsigned CommentColumn;               // Defaults to 60
72
73    /// CommentString - This indicates the comment character used by the
74    /// assembler.
75    const char *CommentString;            // Defaults to "#"
76
77    /// GlobalPrefix - If this is set to a non-empty string, it is prepended
78    /// onto all global symbols.  This is often used for "_" or ".".
79    const char *GlobalPrefix;             // Defaults to ""
80
81    /// PrivateGlobalPrefix - This prefix is used for globals like constant
82    /// pool entries that are completely private to the .s file and should not
83    /// have names in the .o file.  This is often "." or "L".
84    const char *PrivateGlobalPrefix;      // Defaults to "."
85
86    /// LinkerPrivateGlobalPrefix - This prefix is used for symbols that should
87    /// be passed through the assembler but be removed by the linker.  This
88    /// is "l" on Darwin, currently used for some ObjC metadata.
89    const char *LinkerPrivateGlobalPrefix;      // Defaults to ""
90
91    /// JumpTableSpecialLabelPrefix - If not null, a extra (dead) label is
92    /// emitted before jump tables with the specified prefix.
93    const char *JumpTableSpecialLabelPrefix;  // Default to null.
94
95    /// GlobalVarAddrPrefix/Suffix - If these are nonempty, these strings
96    /// will enclose any GlobalVariable (that isn't a function)
97    ///
98    const char *GlobalVarAddrPrefix;      // Defaults to ""
99    const char *GlobalVarAddrSuffix;      // Defaults to ""
100
101    /// FunctionAddrPrefix/Suffix - If these are nonempty, these strings
102    /// will enclose any GlobalVariable that points to a function.
103    ///
104    const char *FunctionAddrPrefix;       // Defaults to ""
105    const char *FunctionAddrSuffix;       // Defaults to ""
106
107    /// PersonalityPrefix/Suffix - If these are nonempty, these strings will
108    /// enclose any personality function in the common frame section.
109    ///
110    const char *PersonalityPrefix;        // Defaults to ""
111    const char *PersonalitySuffix;        // Defaults to ""
112
113    /// NeedsIndirectEncoding - If set, we need to set the indirect encoding bit
114    /// for EH in Dwarf.
115    ///
116    bool NeedsIndirectEncoding;           // Defaults to false
117
118    /// InlineAsmStart/End - If these are nonempty, they contain a directive to
119    /// emit before and after an inline assembly statement.
120    const char *InlineAsmStart;           // Defaults to "#APP\n"
121    const char *InlineAsmEnd;             // Defaults to "#NO_APP\n"
122
123    /// AssemblerDialect - Which dialect of an assembler variant to use.
124    unsigned AssemblerDialect;            // Defaults to 0
125
126    /// AllowQuotesInName - This is true if the assembler allows for complex
127    /// symbol names to be surrounded in quotes.  This defaults to false.
128    bool AllowQuotesInName;
129
130    //===--- Data Emission Directives -------------------------------------===//
131
132    /// ZeroDirective - this should be set to the directive used to get some
133    /// number of zero bytes emitted to the current section.  Common cases are
134    /// "\t.zero\t" and "\t.space\t".  If this is set to null, the
135    /// Data*bitsDirective's will be used to emit zero bytes.
136    const char *ZeroDirective;            // Defaults to "\t.zero\t"
137    const char *ZeroDirectiveSuffix;      // Defaults to ""
138
139    /// AsciiDirective - This directive allows emission of an ascii string with
140    /// the standard C escape characters embedded into it.
141    const char *AsciiDirective;           // Defaults to "\t.ascii\t"
142
143    /// AscizDirective - If not null, this allows for special handling of
144    /// zero terminated strings on this target.  This is commonly supported as
145    /// ".asciz".  If a target doesn't support this, it can be set to null.
146    const char *AscizDirective;           // Defaults to "\t.asciz\t"
147
148    /// DataDirectives - These directives are used to output some unit of
149    /// integer data to the current section.  If a data directive is set to
150    /// null, smaller data directives will be used to emit the large sizes.
151    const char *Data8bitsDirective;       // Defaults to "\t.byte\t"
152    const char *Data16bitsDirective;      // Defaults to "\t.short\t"
153    const char *Data32bitsDirective;      // Defaults to "\t.long\t"
154    const char *Data64bitsDirective;      // Defaults to "\t.quad\t"
155
156    /// getDataASDirective - Return the directive that should be used to emit
157    /// data of the specified size to the specified numeric address space.
158    virtual const char *getDataASDirective(unsigned Size, unsigned AS) const {
159      assert(AS != 0 && "Don't know the directives for default addr space");
160      return NULL;
161    }
162
163    /// SunStyleELFSectionSwitchSyntax - This is true if this target uses "Sun
164    /// Style" syntax for section switching ("#alloc,#write" etc) instead of the
165    /// normal ELF syntax (,"a,w") in .section directives.
166    bool SunStyleELFSectionSwitchSyntax;   // Defaults to false.
167
168    /// UsesELFSectionDirectiveForBSS - This is true if this target uses ELF
169    /// '.section' directive before the '.bss' one. It's used for PPC/Linux
170    /// which doesn't support the '.bss' directive only.
171    bool UsesELFSectionDirectiveForBSS;  // Defaults to false.
172
173    //===--- Alignment Information ----------------------------------------===//
174
175    /// AlignDirective - The directive used to emit round up to an alignment
176    /// boundary.
177    ///
178    const char *AlignDirective;           // Defaults to "\t.align\t"
179
180    /// AlignmentIsInBytes - If this is true (the default) then the asmprinter
181    /// emits ".align N" directives, where N is the number of bytes to align to.
182    /// Otherwise, it emits ".align log2(N)", e.g. 3 to align to an 8 byte
183    /// boundary.
184    bool AlignmentIsInBytes;              // Defaults to true
185
186    /// TextAlignFillValue - If non-zero, this is used to fill the executable
187    /// space created as the result of a alignment directive.
188    unsigned TextAlignFillValue;
189
190    //===--- Section Switching Directives ---------------------------------===//
191
192    /// JumpTableDirective - if non-null, the directive to emit before jump
193    /// table entries.  FIXME: REMOVE THIS.
194    const char *JumpTableDirective;
195    const char *PICJumpTableDirective;
196
197
198    //===--- Global Variable Emission Directives --------------------------===//
199
200    /// GlobalDirective - This is the directive used to declare a global entity.
201    ///
202    const char *GlobalDirective;          // Defaults to NULL.
203
204    /// ExternDirective - This is the directive used to declare external
205    /// globals.
206    ///
207    const char *ExternDirective;          // Defaults to NULL.
208
209    /// SetDirective - This is the name of a directive that can be used to tell
210    /// the assembler to set the value of a variable to some expression.
211    const char *SetDirective;             // Defaults to null.
212
213    /// LCOMMDirective - This is the name of a directive (if supported) that can
214    /// be used to efficiently declare a local (internal) block of zero
215    /// initialized data in the .bss/.data section.  The syntax expected is:
216    /// @verbatim <LCOMMDirective> SYMBOLNAME LENGTHINBYTES, ALIGNMENT
217    /// @endverbatim
218    const char *LCOMMDirective;           // Defaults to null.
219
220    const char *COMMDirective;            // Defaults to "\t.comm\t".
221
222    /// COMMDirectiveTakesAlignment - True if COMMDirective take a third
223    /// argument that specifies the alignment of the declaration.
224    bool COMMDirectiveTakesAlignment;     // Defaults to true.
225
226    /// HasDotTypeDotSizeDirective - True if the target has .type and .size
227    /// directives, this is true for most ELF targets.
228    bool HasDotTypeDotSizeDirective;      // Defaults to true.
229
230    /// HasSingleParameterDotFile - True if the target has a single parameter
231    /// .file directive, this is true for ELF targets.
232    bool HasSingleParameterDotFile;      // Defaults to true.
233
234    /// UsedDirective - This directive, if non-null, is used to declare a global
235    /// as being used somehow that the assembler can't see.  This prevents dead
236    /// code elimination on some targets.
237    const char *UsedDirective;            // Defaults to null.
238
239    /// WeakRefDirective - This directive, if non-null, is used to declare a
240    /// global as being a weak undefined symbol.
241    const char *WeakRefDirective;         // Defaults to null.
242
243    /// WeakDefDirective - This directive, if non-null, is used to declare a
244    /// global as being a weak defined symbol.
245    const char *WeakDefDirective;         // Defaults to null.
246
247    /// HiddenDirective - This directive, if non-null, is used to declare a
248    /// global or function as having hidden visibility.
249    const char *HiddenDirective;          // Defaults to "\t.hidden\t".
250
251    /// ProtectedDirective - This directive, if non-null, is used to declare a
252    /// global or function as having protected visibility.
253    const char *ProtectedDirective;       // Defaults to "\t.protected\t".
254
255    //===--- Dwarf Emission Directives -----------------------------------===//
256
257    /// AbsoluteDebugSectionOffsets - True if we should emit abolute section
258    /// offsets for debug information. Defaults to false.
259    bool AbsoluteDebugSectionOffsets;
260
261    /// AbsoluteEHSectionOffsets - True if we should emit abolute section
262    /// offsets for EH information. Defaults to false.
263    bool AbsoluteEHSectionOffsets;
264
265    /// HasLEB128 - True if target asm supports leb128 directives.
266    ///
267    bool HasLEB128; // Defaults to false.
268
269    /// hasDotLocAndDotFile - True if target asm supports .loc and .file
270    /// directives for emitting debugging information.
271    ///
272    bool HasDotLocAndDotFile; // Defaults to false.
273
274    /// SupportsDebugInformation - True if target supports emission of debugging
275    /// information.
276    bool SupportsDebugInformation;
277
278    /// SupportsExceptionHandling - True if target supports
279    /// exception handling.
280    ///
281    // Defaults to None
282    ExceptionHandling::ExceptionsType ExceptionsType;
283
284    /// RequiresFrameSection - true if the Dwarf2 output needs a frame section
285    ///
286    bool DwarfRequiresFrameSection; // Defaults to true.
287
288    /// DwarfUsesInlineInfoSection - True if DwarfDebugInlineSection is used to
289    /// encode inline subroutine information.
290    bool DwarfUsesInlineInfoSection; // Defaults to false.
291
292    /// Is_EHSymbolPrivate - If set, the "_foo.eh" is made private so that it
293    /// doesn't show up in the symbol table of the object file.
294    bool Is_EHSymbolPrivate;                // Defaults to true.
295
296    /// GlobalEHDirective - This is the directive used to make exception frame
297    /// tables globally visible.
298    ///
299    const char *GlobalEHDirective;          // Defaults to NULL.
300
301    /// SupportsWeakEmptyEHFrame - True if target assembler and linker will
302    /// handle a weak_definition of constant 0 for an omitted EH frame.
303    bool SupportsWeakOmittedEHFrame;  // Defaults to true.
304
305    /// DwarfSectionOffsetDirective - Special section offset directive.
306    const char* DwarfSectionOffsetDirective; // Defaults to NULL
307
308    //===--- CBE Asm Translation Table -----------------------------------===//
309
310    const char *const *AsmTransCBE; // Defaults to empty
311
312  public:
313    explicit MCAsmInfo();
314    virtual ~MCAsmInfo();
315
316    /// getSLEB128Size - Compute the number of bytes required for a signed
317    /// leb128 value.
318    static unsigned getSLEB128Size(int Value);
319
320    /// getULEB128Size - Compute the number of bytes required for an unsigned
321    /// leb128 value.
322    static unsigned getULEB128Size(unsigned Value);
323
324    // Data directive accessors.
325    //
326    const char *getData8bitsDirective(unsigned AS = 0) const {
327      return AS == 0 ? Data8bitsDirective : getDataASDirective(8, AS);
328    }
329    const char *getData16bitsDirective(unsigned AS = 0) const {
330      return AS == 0 ? Data16bitsDirective : getDataASDirective(16, AS);
331    }
332    const char *getData32bitsDirective(unsigned AS = 0) const {
333      return AS == 0 ? Data32bitsDirective : getDataASDirective(32, AS);
334    }
335    const char *getData64bitsDirective(unsigned AS = 0) const {
336      return AS == 0 ? Data64bitsDirective : getDataASDirective(64, AS);
337    }
338
339
340    bool usesSunStyleELFSectionSwitchSyntax() const {
341      return SunStyleELFSectionSwitchSyntax;
342    }
343
344    bool usesELFSectionDirectiveForBSS() const {
345      return UsesELFSectionDirectiveForBSS;
346    }
347
348    // Accessors.
349    //
350    const char *getZeroFillDirective() const {
351      return ZeroFillDirective;
352    }
353    const char *getNonexecutableStackDirective() const {
354      return NonexecutableStackDirective;
355    }
356    bool needsSet() const {
357      return NeedsSet;
358    }
359    unsigned getMaxInstLength() const {
360      return MaxInstLength;
361    }
362    const char *getPCSymbol() const {
363      return PCSymbol;
364    }
365    char getSeparatorChar() const {
366      return SeparatorChar;
367    }
368    unsigned getCommentColumn() const {
369      return CommentColumn;
370    }
371    const char *getCommentString() const {
372      return CommentString;
373    }
374    const char *getGlobalPrefix() const {
375      return GlobalPrefix;
376    }
377    const char *getPrivateGlobalPrefix() const {
378      return PrivateGlobalPrefix;
379    }
380    const char *getLinkerPrivateGlobalPrefix() const {
381      return LinkerPrivateGlobalPrefix;
382    }
383    const char *getJumpTableSpecialLabelPrefix() const {
384      return JumpTableSpecialLabelPrefix;
385    }
386    const char *getGlobalVarAddrPrefix() const {
387      return GlobalVarAddrPrefix;
388    }
389    const char *getGlobalVarAddrSuffix() const {
390      return GlobalVarAddrSuffix;
391    }
392    const char *getFunctionAddrPrefix() const {
393      return FunctionAddrPrefix;
394    }
395    const char *getFunctionAddrSuffix() const {
396      return FunctionAddrSuffix;
397    }
398    const char *getPersonalityPrefix() const {
399      return PersonalityPrefix;
400    }
401    const char *getPersonalitySuffix() const {
402      return PersonalitySuffix;
403    }
404    bool getNeedsIndirectEncoding() const {
405      return NeedsIndirectEncoding;
406    }
407    const char *getInlineAsmStart() const {
408      return InlineAsmStart;
409    }
410    const char *getInlineAsmEnd() const {
411      return InlineAsmEnd;
412    }
413    unsigned getAssemblerDialect() const {
414      return AssemblerDialect;
415    }
416    bool doesAllowQuotesInName() const {
417      return AllowQuotesInName;
418    }
419    const char *getZeroDirective() const {
420      return ZeroDirective;
421    }
422    const char *getZeroDirectiveSuffix() const {
423      return ZeroDirectiveSuffix;
424    }
425    const char *getAsciiDirective() const {
426      return AsciiDirective;
427    }
428    const char *getAscizDirective() const {
429      return AscizDirective;
430    }
431    const char *getJumpTableDirective(bool isPIC) const {
432      return isPIC ? PICJumpTableDirective : JumpTableDirective;
433    }
434    const char *getAlignDirective() const {
435      return AlignDirective;
436    }
437    bool getAlignmentIsInBytes() const {
438      return AlignmentIsInBytes;
439    }
440    unsigned getTextAlignFillValue() const {
441      return TextAlignFillValue;
442    }
443    const char *getGlobalDirective() const {
444      return GlobalDirective;
445    }
446    const char *getExternDirective() const {
447      return ExternDirective;
448    }
449    const char *getSetDirective() const {
450      return SetDirective;
451    }
452    const char *getLCOMMDirective() const {
453      return LCOMMDirective;
454    }
455    const char *getCOMMDirective() const {
456      return COMMDirective;
457    }
458    bool getCOMMDirectiveTakesAlignment() const {
459      return COMMDirectiveTakesAlignment;
460    }
461    bool hasDotTypeDotSizeDirective() const {
462      return HasDotTypeDotSizeDirective;
463    }
464    bool hasSingleParameterDotFile() const {
465      return HasSingleParameterDotFile;
466    }
467    const char *getUsedDirective() const {
468      return UsedDirective;
469    }
470    const char *getWeakRefDirective() const {
471      return WeakRefDirective;
472    }
473    const char *getWeakDefDirective() const {
474      return WeakDefDirective;
475    }
476    const char *getHiddenDirective() const {
477      return HiddenDirective;
478    }
479    const char *getProtectedDirective() const {
480      return ProtectedDirective;
481    }
482    bool isAbsoluteDebugSectionOffsets() const {
483      return AbsoluteDebugSectionOffsets;
484    }
485    bool isAbsoluteEHSectionOffsets() const {
486      return AbsoluteEHSectionOffsets;
487    }
488    bool hasLEB128() const {
489      return HasLEB128;
490    }
491    bool hasDotLocAndDotFile() const {
492      return HasDotLocAndDotFile;
493    }
494    bool doesSupportDebugInformation() const {
495      return SupportsDebugInformation;
496    }
497    bool doesSupportExceptionHandling() const {
498      return ExceptionsType != ExceptionHandling::None;
499    }
500    ExceptionHandling::ExceptionsType getExceptionHandlingType() const {
501      return ExceptionsType;
502    }
503    bool doesDwarfRequireFrameSection() const {
504      return DwarfRequiresFrameSection;
505    }
506    bool doesDwarfUsesInlineInfoSection() const {
507      return DwarfUsesInlineInfoSection;
508    }
509    bool is_EHSymbolPrivate() const {
510      return Is_EHSymbolPrivate;
511    }
512    const char *getGlobalEHDirective() const {
513      return GlobalEHDirective;
514    }
515    bool getSupportsWeakOmittedEHFrame() const {
516      return SupportsWeakOmittedEHFrame;
517    }
518    const char *getDwarfSectionOffsetDirective() const {
519      return DwarfSectionOffsetDirective;
520    }
521    const char *const *getAsmCBE() const {
522      return AsmTransCBE;
523    }
524  };
525}
526
527#endif
528