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_MC_MCASMINFO_H
17 #define LLVM_MC_MCASMINFO_H
19 #include "llvm/MC/MCDirectives.h"
20 #include "llvm/MC/MCDwarf.h"
21 #include "llvm/MC/MachineLocation.h"
32 namespace ExceptionHandling {
33 enum ExceptionsType { None, DwarfCFI, SjLj, ARM, Win64 };
37 enum LCOMMType { NoAlignment, ByteAlignment, Log2Alignment };
40 /// MCAsmInfo - This class is intended to be used as a base class for asm
41 /// properties and features specific to the target.
44 //===------------------------------------------------------------------===//
45 // Properties to be set by the target writer, used to configure asm printer.
48 /// PointerSize - Pointer size in bytes.
52 /// CalleeSaveStackSlotSize - Size of the stack slot reserved for
53 /// callee-saved registers, in bytes.
54 /// Default is same as pointer size.
55 unsigned CalleeSaveStackSlotSize;
57 /// IsLittleEndian - True if target is little endian.
61 /// StackGrowsUp - True if target stack grow up.
65 /// HasSubsectionsViaSymbols - True if this target has the MachO
66 /// .subsections_via_symbols directive.
67 bool HasSubsectionsViaSymbols; // Default is false.
69 /// HasMachoZeroFillDirective - True if this is a MachO target that supports
70 /// the macho-specific .zerofill directive for emitting BSS Symbols.
71 bool HasMachoZeroFillDirective; // Default is false.
73 /// HasMachoTBSSDirective - True if this is a MachO target that supports
74 /// the macho-specific .tbss directive for emitting thread local BSS Symbols
75 bool HasMachoTBSSDirective; // Default is false.
77 /// HasStaticCtorDtorReferenceInStaticMode - True if the compiler should
78 /// emit a ".reference .constructors_used" or ".reference .destructors_used"
79 /// directive after the a static ctor/dtor list. This directive is only
80 /// emitted in Static relocation model.
81 bool HasStaticCtorDtorReferenceInStaticMode; // Default is false.
83 /// LinkerRequiresNonEmptyDwarfLines - True if the linker has a bug and
84 /// requires that the debug_line section be of a minimum size. In practice
85 /// such a linker requires a non-empty line sequence if a file is present.
86 bool LinkerRequiresNonEmptyDwarfLines; // Default to false.
88 /// MaxInstLength - This is the maximum possible length of an instruction,
89 /// which is needed to compute the size of an inline asm.
90 unsigned MaxInstLength; // Defaults to 4.
92 /// MinInstAlignment - Every possible instruction length is a multiple of
93 /// this value. Factored out in .debug_frame and .debug_line.
94 unsigned MinInstAlignment; // Defaults to 1.
96 /// DollarIsPC - The '$' token, when not referencing an identifier or
97 /// constant, refers to the current PC.
98 bool DollarIsPC; // Defaults to false.
100 /// SeparatorString - This string, if specified, is used to separate
101 /// instructions from each other when on the same line.
102 const char *SeparatorString; // Defaults to ';'
104 /// CommentColumn - This indicates the comment num (zero-based) at
105 /// which asm comments should be printed.
106 unsigned CommentColumn; // Defaults to 40
108 /// CommentString - This indicates the comment character used by the
110 const char *CommentString; // Defaults to "#"
112 /// LabelSuffix - This is appended to emitted labels.
113 const char *LabelSuffix; // Defaults to ":"
115 /// LabelSuffix - This is appended to emitted labels.
116 const char *DebugLabelSuffix; // Defaults to ":"
118 /// This prefix is used for globals like constant pool entries that are
119 /// completely private to the .s file and should not have names in the .o
121 const char *PrivateGlobalPrefix; // Defaults to "L"
123 /// InlineAsmStart/End - If these are nonempty, they contain a directive to
124 /// emit before and after an inline assembly statement.
125 const char *InlineAsmStart; // Defaults to "#APP\n"
126 const char *InlineAsmEnd; // Defaults to "#NO_APP\n"
128 /// Code16Directive, Code32Directive, Code64Directive - These are assembly
129 /// directives that tells the assembler to interpret the following
130 /// instructions differently.
131 const char *Code16Directive; // Defaults to ".code16"
132 const char *Code32Directive; // Defaults to ".code32"
133 const char *Code64Directive; // Defaults to ".code64"
135 /// AssemblerDialect - Which dialect of an assembler variant to use.
136 unsigned AssemblerDialect; // Defaults to 0
138 /// \brief This is true if the assembler allows @ characters in symbol
139 /// names. Defaults to false.
142 /// UseDataRegionDirectives - This is true if data region markers should
143 /// be printed as ".data_region/.end_data_region" directives. If false,
144 /// use "$d/$a" labels instead.
145 bool UseDataRegionDirectives;
147 //===--- Data Emission Directives -------------------------------------===//
149 /// ZeroDirective - this should be set to the directive used to get some
150 /// number of zero bytes emitted to the current section. Common cases are
151 /// "\t.zero\t" and "\t.space\t". If this is set to null, the
152 /// Data*bitsDirective's will be used to emit zero bytes.
153 const char *ZeroDirective; // Defaults to "\t.zero\t"
155 /// AsciiDirective - This directive allows emission of an ascii string with
156 /// the standard C escape characters embedded into it.
157 const char *AsciiDirective; // Defaults to "\t.ascii\t"
159 /// AscizDirective - If not null, this allows for special handling of
160 /// zero terminated strings on this target. This is commonly supported as
161 /// ".asciz". If a target doesn't support this, it can be set to null.
162 const char *AscizDirective; // Defaults to "\t.asciz\t"
164 /// DataDirectives - These directives are used to output some unit of
165 /// integer data to the current section. If a data directive is set to
166 /// null, smaller data directives will be used to emit the large sizes.
167 const char *Data8bitsDirective; // Defaults to "\t.byte\t"
168 const char *Data16bitsDirective; // Defaults to "\t.short\t"
169 const char *Data32bitsDirective; // Defaults to "\t.long\t"
170 const char *Data64bitsDirective; // Defaults to "\t.quad\t"
172 /// GPRel64Directive - if non-null, a directive that is used to emit a word
173 /// which should be relocated as a 64-bit GP-relative offset, e.g. .gpdword
175 const char *GPRel64Directive; // Defaults to NULL.
177 /// GPRel32Directive - if non-null, a directive that is used to emit a word
178 /// which should be relocated as a 32-bit GP-relative offset, e.g. .gpword
179 /// on Mips or .gprel32 on Alpha.
180 const char *GPRel32Directive; // Defaults to NULL.
182 /// SunStyleELFSectionSwitchSyntax - This is true if this target uses "Sun
183 /// Style" syntax for section switching ("#alloc,#write" etc) instead of the
184 /// normal ELF syntax (,"a,w") in .section directives.
185 bool SunStyleELFSectionSwitchSyntax; // Defaults to false.
187 /// UsesELFSectionDirectiveForBSS - This is true if this target uses ELF
188 /// '.section' directive before the '.bss' one. It's used for PPC/Linux
189 /// which doesn't support the '.bss' directive only.
190 bool UsesELFSectionDirectiveForBSS; // Defaults to false.
192 bool NeedsDwarfSectionOffsetDirective;
194 //===--- Alignment Information ----------------------------------------===//
196 /// AlignDirective - The directive used to emit round up to an alignment
199 const char *AlignDirective; // Defaults to "\t.align\t"
201 /// AlignmentIsInBytes - If this is true (the default) then the asmprinter
202 /// emits ".align N" directives, where N is the number of bytes to align to.
203 /// Otherwise, it emits ".align log2(N)", e.g. 3 to align to an 8 byte
205 bool AlignmentIsInBytes; // Defaults to true
207 /// TextAlignFillValue - If non-zero, this is used to fill the executable
208 /// space created as the result of a alignment directive.
209 unsigned TextAlignFillValue; // Defaults to 0
211 //===--- Global Variable Emission Directives --------------------------===//
213 /// GlobalDirective - This is the directive used to declare a global entity.
215 const char *GlobalDirective; // Defaults to NULL.
217 /// HasSetDirective - True if the assembler supports the .set directive.
218 bool HasSetDirective; // Defaults to true.
220 /// HasAggressiveSymbolFolding - False if the assembler requires that we use
225 bool HasAggressiveSymbolFolding; // Defaults to true.
227 /// COMMDirectiveAlignmentIsInBytes - True is .comm's and .lcomms optional
228 /// alignment is to be specified in bytes instead of log2(n).
229 bool COMMDirectiveAlignmentIsInBytes; // Defaults to true;
231 /// LCOMMDirectiveAlignment - Describes if the .lcomm directive for the
232 /// target supports an alignment argument and how it is interpreted.
233 LCOMM::LCOMMType LCOMMDirectiveAlignmentType; // Defaults to NoAlignment.
235 /// HasDotTypeDotSizeDirective - True if the target has .type and .size
236 /// directives, this is true for most ELF targets.
237 bool HasDotTypeDotSizeDirective; // Defaults to true.
239 /// HasSingleParameterDotFile - True if the target has a single parameter
240 /// .file directive, this is true for ELF targets.
241 bool HasSingleParameterDotFile; // Defaults to true.
243 /// hasIdentDirective - True if the target has a .ident directive, this is
244 /// true for ELF targets.
245 bool HasIdentDirective; // Defaults to false.
247 /// HasNoDeadStrip - True if this target supports the MachO .no_dead_strip
249 bool HasNoDeadStrip; // Defaults to false.
251 /// WeakRefDirective - This directive, if non-null, is used to declare a
252 /// global as being a weak undefined symbol.
253 const char *WeakRefDirective; // Defaults to NULL.
255 /// True if we have a directive to declare a global as being a weak
257 bool HasWeakDefDirective; // Defaults to false.
259 /// True if we have a directive to declare a global as being a weak
260 /// defined symbol that can be hidden (unexported).
261 bool HasWeakDefCanBeHiddenDirective; // Defaults to false.
263 /// True if we have a .linkonce directive. This is used on cygwin/mingw.
264 bool HasLinkOnceDirective; // Defaults to false.
266 /// HiddenVisibilityAttr - This attribute, if not MCSA_Invalid, is used to
267 /// declare a symbol as having hidden visibility.
268 MCSymbolAttr HiddenVisibilityAttr; // Defaults to MCSA_Hidden.
270 /// HiddenDeclarationVisibilityAttr - This attribute, if not MCSA_Invalid,
271 /// is used to declare an undefined symbol as having hidden visibility.
272 MCSymbolAttr HiddenDeclarationVisibilityAttr; // Defaults to MCSA_Hidden.
275 /// ProtectedVisibilityAttr - This attribute, if not MCSA_Invalid, is used
276 /// to declare a symbol as having protected visibility.
277 MCSymbolAttr ProtectedVisibilityAttr; // Defaults to MCSA_Protected
279 //===--- Dwarf Emission Directives -----------------------------------===//
281 /// HasLEB128 - True if target asm supports leb128 directives.
282 bool HasLEB128; // Defaults to false.
284 /// SupportsDebugInformation - True if target supports emission of debugging
286 bool SupportsDebugInformation; // Defaults to false.
288 /// SupportsExceptionHandling - True if target supports exception handling.
289 ExceptionHandling::ExceptionsType ExceptionsType; // Defaults to None
291 /// DwarfUsesRelocationsAcrossSections - True if Dwarf2 output generally
292 /// uses relocations for references to other .debug_* sections.
293 bool DwarfUsesRelocationsAcrossSections;
295 /// DwarfFDESymbolsUseAbsDiff - true if DWARF FDE symbol reference
296 /// relocations should be replaced by an absolute difference.
297 bool DwarfFDESymbolsUseAbsDiff;
299 /// DwarfRegNumForCFI - True if dwarf register numbers are printed
300 /// instead of symbolic register names in .cfi_* directives.
301 bool DwarfRegNumForCFI; // Defaults to false;
303 /// UseParensForSymbolVariant - True if target uses parens to indicate the
304 /// symbol variant instead of @. For example, foo(plt) instead of foo@plt.
305 bool UseParensForSymbolVariant; // Defaults to false;
307 //===--- Prologue State ----------------------------------------------===//
309 std::vector<MCCFIInstruction> InitialFrameState;
312 explicit MCAsmInfo();
313 virtual ~MCAsmInfo();
315 // FIXME: move these methods to DwarfPrinter when the JIT stops using them.
316 static unsigned getSLEB128Size(int64_t Value);
317 static unsigned getULEB128Size(uint64_t Value);
319 /// getPointerSize - Get the pointer size in bytes.
320 unsigned getPointerSize() const {
324 /// getCalleeSaveStackSlotSize - Get the callee-saved register stack slot
326 unsigned getCalleeSaveStackSlotSize() const {
327 return CalleeSaveStackSlotSize;
330 /// isLittleEndian - True if the target is little endian.
331 bool isLittleEndian() const {
332 return IsLittleEndian;
335 /// isStackGrowthDirectionUp - True if target stack grow up.
336 bool isStackGrowthDirectionUp() const {
340 bool hasSubsectionsViaSymbols() const { return HasSubsectionsViaSymbols; }
342 // Data directive accessors.
344 const char *getData8bitsDirective() const {
345 return Data8bitsDirective;
347 const char *getData16bitsDirective() const {
348 return Data16bitsDirective;
350 const char *getData32bitsDirective() const {
351 return Data32bitsDirective;
353 const char *getData64bitsDirective() const {
354 return Data64bitsDirective;
356 const char *getGPRel64Directive() const { return GPRel64Directive; }
357 const char *getGPRel32Directive() const { return GPRel32Directive; }
359 /// getNonexecutableStackSection - Targets can implement this method to
360 /// specify a section to switch to if the translation unit doesn't have any
361 /// trampolines that require an executable stack.
362 virtual const MCSection *getNonexecutableStackSection(MCContext &Ctx) const{
366 virtual const MCExpr *
367 getExprForPersonalitySymbol(const MCSymbol *Sym,
369 MCStreamer &Streamer) const;
372 getExprForFDESymbol(const MCSymbol *Sym,
374 MCStreamer &Streamer) const;
376 bool usesSunStyleELFSectionSwitchSyntax() const {
377 return SunStyleELFSectionSwitchSyntax;
380 bool usesELFSectionDirectiveForBSS() const {
381 return UsesELFSectionDirectiveForBSS;
384 bool needsDwarfSectionOffsetDirective() const {
385 return NeedsDwarfSectionOffsetDirective;
390 bool hasMachoZeroFillDirective() const { return HasMachoZeroFillDirective; }
391 bool hasMachoTBSSDirective() const { return HasMachoTBSSDirective; }
392 bool hasStaticCtorDtorReferenceInStaticMode() const {
393 return HasStaticCtorDtorReferenceInStaticMode;
395 bool getLinkerRequiresNonEmptyDwarfLines() const {
396 return LinkerRequiresNonEmptyDwarfLines;
398 unsigned getMaxInstLength() const {
399 return MaxInstLength;
401 unsigned getMinInstAlignment() const {
402 return MinInstAlignment;
404 bool getDollarIsPC() const {
407 const char *getSeparatorString() const {
408 return SeparatorString;
410 unsigned getCommentColumn() const {
411 return CommentColumn;
413 const char *getCommentString() const {
414 return CommentString;
416 const char *getLabelSuffix() const {
420 const char *getDebugLabelSuffix() const {
421 return DebugLabelSuffix;
423 const char *getPrivateGlobalPrefix() const {
424 return PrivateGlobalPrefix;
426 const char *getInlineAsmStart() const {
427 return InlineAsmStart;
429 const char *getInlineAsmEnd() const {
432 const char *getCode16Directive() const {
433 return Code16Directive;
435 const char *getCode32Directive() const {
436 return Code32Directive;
438 const char *getCode64Directive() const {
439 return Code64Directive;
441 unsigned getAssemblerDialect() const {
442 return AssemblerDialect;
444 bool doesAllowAtInName() const {
445 return AllowAtInName;
447 bool doesSupportDataRegionDirectives() const {
448 return UseDataRegionDirectives;
450 const char *getZeroDirective() const {
451 return ZeroDirective;
453 const char *getAsciiDirective() const {
454 return AsciiDirective;
456 const char *getAscizDirective() const {
457 return AscizDirective;
459 const char *getAlignDirective() const {
460 return AlignDirective;
462 bool getAlignmentIsInBytes() const {
463 return AlignmentIsInBytes;
465 unsigned getTextAlignFillValue() const {
466 return TextAlignFillValue;
468 const char *getGlobalDirective() const {
469 return GlobalDirective;
471 bool hasSetDirective() const { return HasSetDirective; }
472 bool hasAggressiveSymbolFolding() const {
473 return HasAggressiveSymbolFolding;
475 bool getCOMMDirectiveAlignmentIsInBytes() const {
476 return COMMDirectiveAlignmentIsInBytes;
478 LCOMM::LCOMMType getLCOMMDirectiveAlignmentType() const {
479 return LCOMMDirectiveAlignmentType;
481 bool hasDotTypeDotSizeDirective() const {return HasDotTypeDotSizeDirective;}
482 bool hasSingleParameterDotFile() const { return HasSingleParameterDotFile; }
483 bool hasIdentDirective() const { return HasIdentDirective; }
484 bool hasNoDeadStrip() const { return HasNoDeadStrip; }
485 const char *getWeakRefDirective() const { return WeakRefDirective; }
486 bool hasWeakDefDirective() const { return HasWeakDefDirective; }
487 bool hasWeakDefCanBeHiddenDirective() const {
488 return HasWeakDefCanBeHiddenDirective;
490 bool hasLinkOnceDirective() const { return HasLinkOnceDirective; }
492 MCSymbolAttr getHiddenVisibilityAttr() const { return HiddenVisibilityAttr;}
493 MCSymbolAttr getHiddenDeclarationVisibilityAttr() const {
494 return HiddenDeclarationVisibilityAttr;
496 MCSymbolAttr getProtectedVisibilityAttr() const {
497 return ProtectedVisibilityAttr;
499 bool hasLEB128() const {
502 bool doesSupportDebugInformation() const {
503 return SupportsDebugInformation;
505 bool doesSupportExceptionHandling() const {
506 return ExceptionsType != ExceptionHandling::None;
508 ExceptionHandling::ExceptionsType getExceptionHandlingType() const {
509 return ExceptionsType;
511 bool isExceptionHandlingDwarf() const {
513 (ExceptionsType == ExceptionHandling::DwarfCFI ||
514 ExceptionsType == ExceptionHandling::ARM ||
515 ExceptionsType == ExceptionHandling::Win64);
517 bool doesDwarfUseRelocationsAcrossSections() const {
518 return DwarfUsesRelocationsAcrossSections;
520 bool doDwarfFDESymbolsUseAbsDiff() const {
521 return DwarfFDESymbolsUseAbsDiff;
523 bool useDwarfRegNumForCFI() const {
524 return DwarfRegNumForCFI;
526 bool useParensForSymbolVariant() const {
527 return UseParensForSymbolVariant;
530 void addInitialFrameState(const MCCFIInstruction &Inst) {
531 InitialFrameState.push_back(Inst);
534 const std::vector<MCCFIInstruction> &getInitialFrameState() const {
535 return InitialFrameState;