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 }; }
29 //===------------------------------------------------------------------===//
30 // Properties to be set by the target writer, used to configure asm printer.
33 /// NonexecutableStackDirective - Directive for declaring to the
34 /// linker and beyond that the emitted code does not require stack
35 /// memory to be executable.
36 const char *NonexecutableStackDirective; // Default is null.
38 /// HasMachoZeroFillDirective - True if this is a MachO target that supports
39 /// the macho-specific .zerofill directive for emitting BSS Symbols.
40 bool HasMachoZeroFillDirective; // Default is false.
42 /// HasStaticCtorDtorReferenceInStaticMode - True if the compiler should
43 /// emit a ".reference .constructors_used" or ".reference .destructors_used"
44 /// directive after the a static ctor/dtor list. This directive is only
45 /// emitted in Static relocation model.
46 bool HasStaticCtorDtorReferenceInStaticMode; // Default is false.
48 /// NeedsSet - True if target asm treats expressions in data directives
49 /// as linktime-relocatable. For assembly-time computation, we need to
53 /// is computed at assembly time, while
55 /// is relocated if the relative locations of x and y change at linktime.
56 /// We want both these things in different places.
57 bool NeedsSet; // Defaults to false.
59 /// MaxInstLength - This is the maximum possible length of an instruction,
60 /// which is needed to compute the size of an inline asm.
61 unsigned MaxInstLength; // Defaults to 4.
63 /// PCSymbol - The symbol used to represent the current PC. Used in PC
64 /// relative expressions.
65 const char *PCSymbol; // Defaults to "$".
67 /// SeparatorChar - This character, if specified, is used to separate
68 /// instructions from each other when on the same line. This is used to
69 /// measure inline asm instructions.
70 char SeparatorChar; // Defaults to ';'
72 /// CommentColumn - This indicates the comment num (zero-based) at
73 /// which asm comments should be printed.
74 unsigned CommentColumn; // Defaults to 60
76 /// CommentString - This indicates the comment character used by the
78 const char *CommentString; // Defaults to "#"
80 /// GlobalPrefix - If this is set to a non-empty string, it is prepended
81 /// onto all global symbols. This is often used for "_" or ".".
82 const char *GlobalPrefix; // Defaults to ""
84 /// PrivateGlobalPrefix - This prefix is used for globals like constant
85 /// pool entries that are completely private to the .s file and should not
86 /// have names in the .o file. This is often "." or "L".
87 const char *PrivateGlobalPrefix; // Defaults to "."
89 /// LinkerPrivateGlobalPrefix - This prefix is used for symbols that should
90 /// be passed through the assembler but be removed by the linker. This
91 /// is "l" on Darwin, currently used for some ObjC metadata.
92 const char *LinkerPrivateGlobalPrefix; // Defaults to ""
94 /// InlineAsmStart/End - If these are nonempty, they contain a directive to
95 /// emit before and after an inline assembly statement.
96 const char *InlineAsmStart; // Defaults to "#APP\n"
97 const char *InlineAsmEnd; // Defaults to "#NO_APP\n"
99 /// AssemblerDialect - Which dialect of an assembler variant to use.
100 unsigned AssemblerDialect; // Defaults to 0
102 /// AllowQuotesInName - This is true if the assembler allows for complex
103 /// symbol names to be surrounded in quotes. This defaults to false.
104 bool AllowQuotesInName;
106 /// AllowNameToStartWithDigit - This is true if the assembler allows symbol
107 /// names to start with a digit (e.g., "0x0021"). This defaults to false.
108 bool AllowNameToStartWithDigit;
110 //===--- Data Emission Directives -------------------------------------===//
112 /// ZeroDirective - this should be set to the directive used to get some
113 /// number of zero bytes emitted to the current section. Common cases are
114 /// "\t.zero\t" and "\t.space\t". If this is set to null, the
115 /// Data*bitsDirective's will be used to emit zero bytes.
116 const char *ZeroDirective; // Defaults to "\t.zero\t"
118 /// AsciiDirective - This directive allows emission of an ascii string with
119 /// the standard C escape characters embedded into it.
120 const char *AsciiDirective; // Defaults to "\t.ascii\t"
122 /// AscizDirective - If not null, this allows for special handling of
123 /// zero terminated strings on this target. This is commonly supported as
124 /// ".asciz". If a target doesn't support this, it can be set to null.
125 const char *AscizDirective; // Defaults to "\t.asciz\t"
127 /// DataDirectives - These directives are used to output some unit of
128 /// integer data to the current section. If a data directive is set to
129 /// null, smaller data directives will be used to emit the large sizes.
130 const char *Data8bitsDirective; // Defaults to "\t.byte\t"
131 const char *Data16bitsDirective; // Defaults to "\t.short\t"
132 const char *Data32bitsDirective; // Defaults to "\t.long\t"
133 const char *Data64bitsDirective; // Defaults to "\t.quad\t"
135 /// getDataASDirective - Return the directive that should be used to emit
136 /// data of the specified size to the specified numeric address space.
137 virtual const char *getDataASDirective(unsigned Size, unsigned AS) const {
138 assert(AS != 0 && "Don't know the directives for default addr space");
142 /// SunStyleELFSectionSwitchSyntax - This is true if this target uses "Sun
143 /// Style" syntax for section switching ("#alloc,#write" etc) instead of the
144 /// normal ELF syntax (,"a,w") in .section directives.
145 bool SunStyleELFSectionSwitchSyntax; // Defaults to false.
147 /// UsesELFSectionDirectiveForBSS - This is true if this target uses ELF
148 /// '.section' directive before the '.bss' one. It's used for PPC/Linux
149 /// which doesn't support the '.bss' directive only.
150 bool UsesELFSectionDirectiveForBSS; // Defaults to false.
152 //===--- Alignment Information ----------------------------------------===//
154 /// AlignDirective - The directive used to emit round up to an alignment
157 const char *AlignDirective; // Defaults to "\t.align\t"
159 /// AlignmentIsInBytes - If this is true (the default) then the asmprinter
160 /// emits ".align N" directives, where N is the number of bytes to align to.
161 /// Otherwise, it emits ".align log2(N)", e.g. 3 to align to an 8 byte
163 bool AlignmentIsInBytes; // Defaults to true
165 /// TextAlignFillValue - If non-zero, this is used to fill the executable
166 /// space created as the result of a alignment directive.
167 unsigned TextAlignFillValue; // Defaults to 0
169 //===--- Section Switching Directives ---------------------------------===//
171 /// JumpTableDirective - if non-null, the directive to emit before jump
172 /// table entries. FIXME: REMOVE THIS.
173 const char *JumpTableDirective; // Defaults to NULL.
174 const char *PICJumpTableDirective; // Defaults to NULL.
177 //===--- Global Variable Emission Directives --------------------------===//
179 /// GlobalDirective - This is the directive used to declare a global entity.
181 const char *GlobalDirective; // Defaults to NULL.
183 /// ExternDirective - This is the directive used to declare external
186 const char *ExternDirective; // Defaults to NULL.
188 /// SetDirective - This is the name of a directive that can be used to tell
189 /// the assembler to set the value of a variable to some expression.
190 const char *SetDirective; // Defaults to null.
192 /// LCOMMDirective - This is the name of a directive (if supported) that can
193 /// be used to efficiently declare a local (internal) block of zero
194 /// initialized data in the .bss/.data section. The syntax expected is:
195 /// @verbatim <LCOMMDirective> SYMBOLNAME LENGTHINBYTES
197 const char *LCOMMDirective; // Defaults to null.
199 const char *COMMDirective; // Defaults to "\t.comm\t".
201 /// COMMDirectiveTakesAlignment - True if COMMDirective take a third
202 /// argument that specifies the alignment of the declaration.
203 bool COMMDirectiveTakesAlignment; // Defaults to true.
205 /// HasDotTypeDotSizeDirective - True if the target has .type and .size
206 /// directives, this is true for most ELF targets.
207 bool HasDotTypeDotSizeDirective; // Defaults to true.
209 /// HasSingleParameterDotFile - True if the target has a single parameter
210 /// .file directive, this is true for ELF targets.
211 bool HasSingleParameterDotFile; // Defaults to true.
213 /// UsedDirective - This directive, if non-null, is used to declare a global
214 /// as being used somehow that the assembler can't see. This prevents dead
215 /// code elimination on some targets.
216 const char *UsedDirective; // Defaults to NULL.
218 /// WeakRefDirective - This directive, if non-null, is used to declare a
219 /// global as being a weak undefined symbol.
220 const char *WeakRefDirective; // Defaults to NULL.
222 /// WeakDefDirective - This directive, if non-null, is used to declare a
223 /// global as being a weak defined symbol.
224 const char *WeakDefDirective; // Defaults to NULL.
226 /// LinkOnceDirective - This directive, if non-null is used to declare a
227 /// global as being a weak defined symbol. This is used on cygwin/mingw.
228 const char *LinkOnceDirective; // Defaults to NULL.
230 /// HiddenDirective - This directive, if non-null, is used to declare a
231 /// global or function as having hidden visibility.
232 const char *HiddenDirective; // Defaults to "\t.hidden\t".
234 /// ProtectedDirective - This directive, if non-null, is used to declare a
235 /// global or function as having protected visibility.
236 const char *ProtectedDirective; // Defaults to "\t.protected\t".
238 //===--- Dwarf Emission Directives -----------------------------------===//
240 /// AbsoluteDebugSectionOffsets - True if we should emit abolute section
241 /// offsets for debug information.
242 bool AbsoluteDebugSectionOffsets; // Defaults to false.
244 /// AbsoluteEHSectionOffsets - True if we should emit abolute section
245 /// offsets for EH information. Defaults to false.
246 bool AbsoluteEHSectionOffsets;
248 /// HasLEB128 - True if target asm supports leb128 directives.
249 bool HasLEB128; // Defaults to false.
251 /// hasDotLocAndDotFile - True if target asm supports .loc and .file
252 /// directives for emitting debugging information.
253 bool HasDotLocAndDotFile; // Defaults to false.
255 /// SupportsDebugInformation - True if target supports emission of debugging
257 bool SupportsDebugInformation; // Defaults to false.
259 /// SupportsExceptionHandling - True if target supports exception handling.
260 ExceptionHandling::ExceptionsType ExceptionsType; // Defaults to None
262 /// RequiresFrameSection - true if the Dwarf2 output needs a frame section
263 bool DwarfRequiresFrameSection; // Defaults to true.
265 /// DwarfUsesInlineInfoSection - True if DwarfDebugInlineSection is used to
266 /// encode inline subroutine information.
267 bool DwarfUsesInlineInfoSection; // Defaults to false.
269 /// Is_EHSymbolPrivate - If set, the "_foo.eh" is made private so that it
270 /// doesn't show up in the symbol table of the object file.
271 bool Is_EHSymbolPrivate; // Defaults to true.
273 /// GlobalEHDirective - This is the directive used to make exception frame
274 /// tables globally visible.
275 const char *GlobalEHDirective; // Defaults to NULL.
277 /// SupportsWeakEmptyEHFrame - True if target assembler and linker will
278 /// handle a weak_definition of constant 0 for an omitted EH frame.
279 bool SupportsWeakOmittedEHFrame; // Defaults to true.
281 /// DwarfSectionOffsetDirective - Special section offset directive.
282 const char* DwarfSectionOffsetDirective; // Defaults to NULL
284 //===--- CBE Asm Translation Table -----------------------------------===//
286 const char *const *AsmTransCBE; // Defaults to empty
289 explicit MCAsmInfo(bool isLittleEndian);
290 virtual ~MCAsmInfo();
292 bool isLittleEndian() const { return IsLittleEndian; }
293 bool isBigEndian() const { return !IsLittleEndian; }
295 /// getSLEB128Size - Compute the number of bytes required for a signed
297 static unsigned getSLEB128Size(int Value);
299 /// getULEB128Size - Compute the number of bytes required for an unsigned
301 static unsigned getULEB128Size(unsigned Value);
303 // Data directive accessors.
305 const char *getData8bitsDirective(unsigned AS = 0) const {
306 return AS == 0 ? Data8bitsDirective : getDataASDirective(8, AS);
308 const char *getData16bitsDirective(unsigned AS = 0) const {
309 return AS == 0 ? Data16bitsDirective : getDataASDirective(16, AS);
311 const char *getData32bitsDirective(unsigned AS = 0) const {
312 return AS == 0 ? Data32bitsDirective : getDataASDirective(32, AS);
314 const char *getData64bitsDirective(unsigned AS = 0) const {
315 return AS == 0 ? Data64bitsDirective : getDataASDirective(64, AS);
319 bool usesSunStyleELFSectionSwitchSyntax() const {
320 return SunStyleELFSectionSwitchSyntax;
323 bool usesELFSectionDirectiveForBSS() const {
324 return UsesELFSectionDirectiveForBSS;
329 bool hasMachoZeroFillDirective() const { return HasMachoZeroFillDirective; }
330 bool hasStaticCtorDtorReferenceInStaticMode() const {
331 return HasStaticCtorDtorReferenceInStaticMode;
333 const char *getNonexecutableStackDirective() const {
334 return NonexecutableStackDirective;
336 bool needsSet() const {
339 unsigned getMaxInstLength() const {
340 return MaxInstLength;
342 const char *getPCSymbol() const {
345 char getSeparatorChar() const {
346 return SeparatorChar;
348 unsigned getCommentColumn() const {
349 return CommentColumn;
351 const char *getCommentString() const {
352 return CommentString;
354 const char *getGlobalPrefix() const {
357 const char *getPrivateGlobalPrefix() const {
358 return PrivateGlobalPrefix;
360 const char *getLinkerPrivateGlobalPrefix() const {
361 return LinkerPrivateGlobalPrefix;
363 const char *getInlineAsmStart() const {
364 return InlineAsmStart;
366 const char *getInlineAsmEnd() const {
369 unsigned getAssemblerDialect() const {
370 return AssemblerDialect;
372 bool doesAllowQuotesInName() const {
373 return AllowQuotesInName;
375 bool doesAllowNameToStartWithDigit() const {
376 return AllowNameToStartWithDigit;
378 const char *getZeroDirective() const {
379 return ZeroDirective;
381 const char *getAsciiDirective() const {
382 return AsciiDirective;
384 const char *getAscizDirective() const {
385 return AscizDirective;
387 const char *getJumpTableDirective(bool isPIC) const {
388 return isPIC ? PICJumpTableDirective : JumpTableDirective;
390 const char *getAlignDirective() const {
391 return AlignDirective;
393 bool getAlignmentIsInBytes() const {
394 return AlignmentIsInBytes;
396 unsigned getTextAlignFillValue() const {
397 return TextAlignFillValue;
399 const char *getGlobalDirective() const {
400 return GlobalDirective;
402 const char *getExternDirective() const {
403 return ExternDirective;
405 const char *getSetDirective() const {
408 const char *getLCOMMDirective() const {
409 return LCOMMDirective;
411 const char *getCOMMDirective() const {
412 return COMMDirective;
414 bool getCOMMDirectiveTakesAlignment() const {
415 return COMMDirectiveTakesAlignment;
417 bool hasDotTypeDotSizeDirective() const {
418 return HasDotTypeDotSizeDirective;
420 bool hasSingleParameterDotFile() const {
421 return HasSingleParameterDotFile;
423 const char *getUsedDirective() const {
424 return UsedDirective;
426 const char *getWeakRefDirective() const { return WeakRefDirective; }
427 const char *getWeakDefDirective() const { return WeakDefDirective; }
428 const char *getLinkOnceDirective() const { return LinkOnceDirective; }
429 const char *getHiddenDirective() const {
430 return HiddenDirective;
432 const char *getProtectedDirective() const {
433 return ProtectedDirective;
435 bool isAbsoluteDebugSectionOffsets() const {
436 return AbsoluteDebugSectionOffsets;
438 bool isAbsoluteEHSectionOffsets() const {
439 return AbsoluteEHSectionOffsets;
441 bool hasLEB128() const {
444 bool hasDotLocAndDotFile() const {
445 return HasDotLocAndDotFile;
447 bool doesSupportDebugInformation() const {
448 return SupportsDebugInformation;
450 bool doesSupportExceptionHandling() const {
451 return ExceptionsType != ExceptionHandling::None;
453 ExceptionHandling::ExceptionsType getExceptionHandlingType() const {
454 return ExceptionsType;
456 bool doesDwarfRequireFrameSection() const {
457 return DwarfRequiresFrameSection;
459 bool doesDwarfUsesInlineInfoSection() const {
460 return DwarfUsesInlineInfoSection;
462 bool is_EHSymbolPrivate() const {
463 return Is_EHSymbolPrivate;
465 const char *getGlobalEHDirective() const {
466 return GlobalEHDirective;
468 bool getSupportsWeakOmittedEHFrame() const {
469 return SupportsWeakOmittedEHFrame;
471 const char *getDwarfSectionOffsetDirective() const {
472 return DwarfSectionOffsetDirective;
474 const char *const *getAsmCBE() const {