1 //===-- llvm/MC/MCAsmInfo.h - Asm info --------------------------*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
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.
14 //===----------------------------------------------------------------------===//
16 #ifndef LLVM_TARGET_ASM_INFO_H
17 #define LLVM_TARGET_ASM_INFO_H
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 }; }
28 //===------------------------------------------------------------------===//
29 // Properties to be set by the target writer, used to configure asm printer.
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.
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.
41 /// NeedsSet - True if target asm treats expressions in data directives
42 /// as linktime-relocatable. For assembly-time computation, we need to
46 /// is computed at assembly time, while
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.
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.
56 /// PCSymbol - The symbol used to represent the current PC. Used in PC
57 /// relative expressions.
58 const char *PCSymbol; // Defaults to "$".
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 ';'
65 /// CommentColumn - This indicates the comment num (zero-based) at
66 /// which asm comments should be printed.
67 unsigned CommentColumn; // Defaults to 60
69 /// CommentString - This indicates the comment character used by the
71 const char *CommentString; // Defaults to "#"
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 ""
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 "."
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 ""
87 /// InlineAsmStart/End - If these are nonempty, they contain a directive to
88 /// emit before and after an inline assembly statement.
89 const char *InlineAsmStart; // Defaults to "#APP\n"
90 const char *InlineAsmEnd; // Defaults to "#NO_APP\n"
92 /// AssemblerDialect - Which dialect of an assembler variant to use.
93 unsigned AssemblerDialect; // Defaults to 0
95 /// AllowQuotesInName - This is true if the assembler allows for complex
96 /// symbol names to be surrounded in quotes. This defaults to false.
97 bool AllowQuotesInName;
99 /// AllowNameToStartWithDigit - This is true if the assembler allows symbol
100 /// names to start with a digit (e.g., "0x0021"). This defaults to false.
101 bool AllowNameToStartWithDigit;
103 //===--- Data Emission Directives -------------------------------------===//
105 /// ZeroDirective - this should be set to the directive used to get some
106 /// number of zero bytes emitted to the current section. Common cases are
107 /// "\t.zero\t" and "\t.space\t". If this is set to null, the
108 /// Data*bitsDirective's will be used to emit zero bytes.
109 const char *ZeroDirective; // Defaults to "\t.zero\t"
110 const char *ZeroDirectiveSuffix; // Defaults to ""
112 /// AsciiDirective - This directive allows emission of an ascii string with
113 /// the standard C escape characters embedded into it.
114 const char *AsciiDirective; // Defaults to "\t.ascii\t"
116 /// AscizDirective - If not null, this allows for special handling of
117 /// zero terminated strings on this target. This is commonly supported as
118 /// ".asciz". If a target doesn't support this, it can be set to null.
119 const char *AscizDirective; // Defaults to "\t.asciz\t"
121 /// DataDirectives - These directives are used to output some unit of
122 /// integer data to the current section. If a data directive is set to
123 /// null, smaller data directives will be used to emit the large sizes.
124 const char *Data8bitsDirective; // Defaults to "\t.byte\t"
125 const char *Data16bitsDirective; // Defaults to "\t.short\t"
126 const char *Data32bitsDirective; // Defaults to "\t.long\t"
127 const char *Data64bitsDirective; // Defaults to "\t.quad\t"
129 /// getDataASDirective - Return the directive that should be used to emit
130 /// data of the specified size to the specified numeric address space.
131 virtual const char *getDataASDirective(unsigned Size, unsigned AS) const {
132 assert(AS != 0 && "Don't know the directives for default addr space");
136 /// SunStyleELFSectionSwitchSyntax - This is true if this target uses "Sun
137 /// Style" syntax for section switching ("#alloc,#write" etc) instead of the
138 /// normal ELF syntax (,"a,w") in .section directives.
139 bool SunStyleELFSectionSwitchSyntax; // Defaults to false.
141 /// UsesELFSectionDirectiveForBSS - This is true if this target uses ELF
142 /// '.section' directive before the '.bss' one. It's used for PPC/Linux
143 /// which doesn't support the '.bss' directive only.
144 bool UsesELFSectionDirectiveForBSS; // Defaults to false.
146 //===--- Alignment Information ----------------------------------------===//
148 /// AlignDirective - The directive used to emit round up to an alignment
151 const char *AlignDirective; // Defaults to "\t.align\t"
153 /// AlignmentIsInBytes - If this is true (the default) then the asmprinter
154 /// emits ".align N" directives, where N is the number of bytes to align to.
155 /// Otherwise, it emits ".align log2(N)", e.g. 3 to align to an 8 byte
157 bool AlignmentIsInBytes; // Defaults to true
159 /// TextAlignFillValue - If non-zero, this is used to fill the executable
160 /// space created as the result of a alignment directive.
161 unsigned TextAlignFillValue; // Defaults to 0
163 //===--- Section Switching Directives ---------------------------------===//
165 /// JumpTableDirective - if non-null, the directive to emit before jump
166 /// table entries. FIXME: REMOVE THIS.
167 const char *JumpTableDirective; // Defaults to NULL.
168 const char *PICJumpTableDirective; // Defaults to NULL.
171 //===--- Global Variable Emission Directives --------------------------===//
173 /// GlobalDirective - This is the directive used to declare a global entity.
175 const char *GlobalDirective; // Defaults to NULL.
177 /// ExternDirective - This is the directive used to declare external
180 const char *ExternDirective; // Defaults to NULL.
182 /// SetDirective - This is the name of a directive that can be used to tell
183 /// the assembler to set the value of a variable to some expression.
184 const char *SetDirective; // Defaults to null.
186 /// LCOMMDirective - This is the name of a directive (if supported) that can
187 /// be used to efficiently declare a local (internal) block of zero
188 /// initialized data in the .bss/.data section. The syntax expected is:
189 /// @verbatim <LCOMMDirective> SYMBOLNAME LENGTHINBYTES, ALIGNMENT
191 const char *LCOMMDirective; // Defaults to null.
193 const char *COMMDirective; // Defaults to "\t.comm\t".
195 /// COMMDirectiveTakesAlignment - True if COMMDirective take a third
196 /// argument that specifies the alignment of the declaration.
197 bool COMMDirectiveTakesAlignment; // Defaults to true.
199 /// HasDotTypeDotSizeDirective - True if the target has .type and .size
200 /// directives, this is true for most ELF targets.
201 bool HasDotTypeDotSizeDirective; // Defaults to true.
203 /// HasSingleParameterDotFile - True if the target has a single parameter
204 /// .file directive, this is true for ELF targets.
205 bool HasSingleParameterDotFile; // Defaults to true.
207 /// UsedDirective - This directive, if non-null, is used to declare a global
208 /// as being used somehow that the assembler can't see. This prevents dead
209 /// code elimination on some targets.
210 const char *UsedDirective; // Defaults to NULL.
212 /// WeakRefDirective - This directive, if non-null, is used to declare a
213 /// global as being a weak undefined symbol.
214 const char *WeakRefDirective; // Defaults to NULL.
216 /// WeakDefDirective - This directive, if non-null, is used to declare a
217 /// global as being a weak defined symbol.
218 const char *WeakDefDirective; // Defaults to NULL.
220 /// HiddenDirective - This directive, if non-null, is used to declare a
221 /// global or function as having hidden visibility.
222 const char *HiddenDirective; // Defaults to "\t.hidden\t".
224 /// ProtectedDirective - This directive, if non-null, is used to declare a
225 /// global or function as having protected visibility.
226 const char *ProtectedDirective; // Defaults to "\t.protected\t".
228 //===--- Dwarf Emission Directives -----------------------------------===//
230 /// AbsoluteDebugSectionOffsets - True if we should emit abolute section
231 /// offsets for debug information.
232 bool AbsoluteDebugSectionOffsets; // Defaults to false.
234 /// AbsoluteEHSectionOffsets - True if we should emit abolute section
235 /// offsets for EH information. Defaults to false.
236 bool AbsoluteEHSectionOffsets;
238 /// HasLEB128 - True if target asm supports leb128 directives.
239 bool HasLEB128; // Defaults to false.
241 /// hasDotLocAndDotFile - True if target asm supports .loc and .file
242 /// directives for emitting debugging information.
243 bool HasDotLocAndDotFile; // Defaults to false.
245 /// SupportsDebugInformation - True if target supports emission of debugging
247 bool SupportsDebugInformation; // Defaults to false.
249 /// SupportsExceptionHandling - True if target supports exception handling.
250 ExceptionHandling::ExceptionsType ExceptionsType; // Defaults to None
252 /// RequiresFrameSection - true if the Dwarf2 output needs a frame section
253 bool DwarfRequiresFrameSection; // Defaults to true.
255 /// DwarfUsesInlineInfoSection - True if DwarfDebugInlineSection is used to
256 /// encode inline subroutine information.
257 bool DwarfUsesInlineInfoSection; // Defaults to false.
259 /// Is_EHSymbolPrivate - If set, the "_foo.eh" is made private so that it
260 /// doesn't show up in the symbol table of the object file.
261 bool Is_EHSymbolPrivate; // Defaults to true.
263 /// GlobalEHDirective - This is the directive used to make exception frame
264 /// tables globally visible.
265 const char *GlobalEHDirective; // Defaults to NULL.
267 /// SupportsWeakEmptyEHFrame - True if target assembler and linker will
268 /// handle a weak_definition of constant 0 for an omitted EH frame.
269 bool SupportsWeakOmittedEHFrame; // Defaults to true.
271 /// DwarfSectionOffsetDirective - Special section offset directive.
272 const char* DwarfSectionOffsetDirective; // Defaults to NULL
274 //===--- CBE Asm Translation Table -----------------------------------===//
276 const char *const *AsmTransCBE; // Defaults to empty
279 explicit MCAsmInfo();
280 virtual ~MCAsmInfo();
282 /// getSLEB128Size - Compute the number of bytes required for a signed
284 static unsigned getSLEB128Size(int Value);
286 /// getULEB128Size - Compute the number of bytes required for an unsigned
288 static unsigned getULEB128Size(unsigned Value);
290 // Data directive accessors.
292 const char *getData8bitsDirective(unsigned AS = 0) const {
293 return AS == 0 ? Data8bitsDirective : getDataASDirective(8, AS);
295 const char *getData16bitsDirective(unsigned AS = 0) const {
296 return AS == 0 ? Data16bitsDirective : getDataASDirective(16, AS);
298 const char *getData32bitsDirective(unsigned AS = 0) const {
299 return AS == 0 ? Data32bitsDirective : getDataASDirective(32, AS);
301 const char *getData64bitsDirective(unsigned AS = 0) const {
302 return AS == 0 ? Data64bitsDirective : getDataASDirective(64, AS);
306 bool usesSunStyleELFSectionSwitchSyntax() const {
307 return SunStyleELFSectionSwitchSyntax;
310 bool usesELFSectionDirectiveForBSS() const {
311 return UsesELFSectionDirectiveForBSS;
316 const char *getZeroFillDirective() const {
317 return ZeroFillDirective;
319 const char *getNonexecutableStackDirective() const {
320 return NonexecutableStackDirective;
322 bool needsSet() const {
325 unsigned getMaxInstLength() const {
326 return MaxInstLength;
328 const char *getPCSymbol() const {
331 char getSeparatorChar() const {
332 return SeparatorChar;
334 unsigned getCommentColumn() const {
335 return CommentColumn;
337 const char *getCommentString() const {
338 return CommentString;
340 const char *getGlobalPrefix() const {
343 const char *getPrivateGlobalPrefix() const {
344 return PrivateGlobalPrefix;
346 const char *getLinkerPrivateGlobalPrefix() const {
347 return LinkerPrivateGlobalPrefix;
349 const char *getInlineAsmStart() const {
350 return InlineAsmStart;
352 const char *getInlineAsmEnd() const {
355 unsigned getAssemblerDialect() const {
356 return AssemblerDialect;
358 bool doesAllowQuotesInName() const {
359 return AllowQuotesInName;
361 bool doesAllowNameToStartWithDigit() const {
362 return AllowNameToStartWithDigit;
364 const char *getZeroDirective() const {
365 return ZeroDirective;
367 const char *getZeroDirectiveSuffix() const {
368 return ZeroDirectiveSuffix;
370 const char *getAsciiDirective() const {
371 return AsciiDirective;
373 const char *getAscizDirective() const {
374 return AscizDirective;
376 const char *getJumpTableDirective(bool isPIC) const {
377 return isPIC ? PICJumpTableDirective : JumpTableDirective;
379 const char *getAlignDirective() const {
380 return AlignDirective;
382 bool getAlignmentIsInBytes() const {
383 return AlignmentIsInBytes;
385 unsigned getTextAlignFillValue() const {
386 return TextAlignFillValue;
388 const char *getGlobalDirective() const {
389 return GlobalDirective;
391 const char *getExternDirective() const {
392 return ExternDirective;
394 const char *getSetDirective() const {
397 const char *getLCOMMDirective() const {
398 return LCOMMDirective;
400 const char *getCOMMDirective() const {
401 return COMMDirective;
403 bool getCOMMDirectiveTakesAlignment() const {
404 return COMMDirectiveTakesAlignment;
406 bool hasDotTypeDotSizeDirective() const {
407 return HasDotTypeDotSizeDirective;
409 bool hasSingleParameterDotFile() const {
410 return HasSingleParameterDotFile;
412 const char *getUsedDirective() const {
413 return UsedDirective;
415 const char *getWeakRefDirective() const {
416 return WeakRefDirective;
418 const char *getWeakDefDirective() const {
419 return WeakDefDirective;
421 const char *getHiddenDirective() const {
422 return HiddenDirective;
424 const char *getProtectedDirective() const {
425 return ProtectedDirective;
427 bool isAbsoluteDebugSectionOffsets() const {
428 return AbsoluteDebugSectionOffsets;
430 bool isAbsoluteEHSectionOffsets() const {
431 return AbsoluteEHSectionOffsets;
433 bool hasLEB128() const {
436 bool hasDotLocAndDotFile() const {
437 return HasDotLocAndDotFile;
439 bool doesSupportDebugInformation() const {
440 return SupportsDebugInformation;
442 bool doesSupportExceptionHandling() const {
443 return ExceptionsType != ExceptionHandling::None;
445 ExceptionHandling::ExceptionsType getExceptionHandlingType() const {
446 return ExceptionsType;
448 bool doesDwarfRequireFrameSection() const {
449 return DwarfRequiresFrameSection;
451 bool doesDwarfUsesInlineInfoSection() const {
452 return DwarfUsesInlineInfoSection;
454 bool is_EHSymbolPrivate() const {
455 return Is_EHSymbolPrivate;
457 const char *getGlobalEHDirective() const {
458 return GlobalEHDirective;
460 bool getSupportsWeakOmittedEHFrame() const {
461 return SupportsWeakOmittedEHFrame;
463 const char *getDwarfSectionOffsetDirective() const {
464 return DwarfSectionOffsetDirective;
466 const char *const *getAsmCBE() const {