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"
33 enum class EncodingType {
35 Alpha, /// Windows Alpha
36 Alpha64, /// Windows AXP64
37 ARM, /// Windows NT (Windows on ARM)
38 CE, /// Windows CE ARM, PowerPC, SH3, SH4
39 Itanium, /// Windows x64, Windows Itanium (IA-64)
44 enum class ExceptionHandling {
45 None, /// No exception support
46 DwarfCFI, /// DWARF-like instruction based exceptions
47 SjLj, /// setjmp/longjmp based exceptions
49 WinEH, /// Windows Exception Handling
53 enum LCOMMType { NoAlignment, ByteAlignment, Log2Alignment };
56 /// This class is intended to be used as a base class for asm
57 /// properties and features specific to the target.
60 //===------------------------------------------------------------------===//
61 // Properties to be set by the target writer, used to configure asm printer.
64 /// Pointer size in bytes. Default is 4.
67 /// Size of the stack slot reserved for callee-saved registers, in bytes.
68 /// Default is same as pointer size.
69 unsigned CalleeSaveStackSlotSize;
71 /// True if target is little endian. Default is true.
74 /// True if target stack grow up. Default is false.
77 /// True if this target has the MachO .subsections_via_symbols directive.
79 bool HasSubsectionsViaSymbols;
81 /// True if this is a MachO target that supports the macho-specific .zerofill
82 /// directive for emitting BSS Symbols. Default is false.
83 bool HasMachoZeroFillDirective;
85 /// True if this is a MachO target that supports the macho-specific .tbss
86 /// directive for emitting thread local BSS Symbols. Default is false.
87 bool HasMachoTBSSDirective;
89 /// True if the compiler should emit a ".reference .constructors_used" or
90 /// ".reference .destructors_used" directive after the static ctor/dtor
91 /// list. This directive is only emitted in Static relocation model. Default
93 bool HasStaticCtorDtorReferenceInStaticMode;
95 /// This is the maximum possible length of an instruction, which is needed to
96 /// compute the size of an inline asm. Defaults to 4.
97 unsigned MaxInstLength;
99 /// Every possible instruction length is a multiple of this value. Factored
100 /// out in .debug_frame and .debug_line. Defaults to 1.
101 unsigned MinInstAlignment;
103 /// The '$' token, when not referencing an identifier or constant, refers to
104 /// the current PC. Defaults to false.
107 /// This string, if specified, is used to separate instructions from each
108 /// other when on the same line. Defaults to ';'
109 const char *SeparatorString;
111 /// This indicates the comment character used by the assembler. Defaults to
113 const char *CommentString;
115 /// This is appended to emitted labels. Defaults to ":"
116 const char *LabelSuffix;
118 // Print the EH begin symbol with an assignment. Defaults to false.
119 bool UseAssignmentForEHBegin;
121 /// This prefix is used for globals like constant pool entries that are
122 /// completely private to the .s file and should not have names in the .o
123 /// file. Defaults to "L"
124 const char *PrivateGlobalPrefix;
126 /// This prefix is used for labels for basic blocks. Defaults to the same as
127 /// PrivateGlobalPrefix.
128 const char *PrivateLabelPrefix;
130 /// This prefix is used for symbols that should be passed through the
131 /// assembler but be removed by the linker. This is 'l' on Darwin, currently
132 /// used for some ObjC metadata. The default of "" meast that for this system
133 /// a plain private symbol should be used. Defaults to "".
134 const char *LinkerPrivateGlobalPrefix;
136 /// If these are nonempty, they contain a directive to emit before and after
137 /// an inline assembly statement. Defaults to "#APP\n", "#NO_APP\n"
138 const char *InlineAsmStart;
139 const char *InlineAsmEnd;
141 /// These are assembly directives that tells the assembler to interpret the
142 /// following instructions differently. Defaults to ".code16", ".code32",
144 const char *Code16Directive;
145 const char *Code32Directive;
146 const char *Code64Directive;
148 /// Which dialect of an assembler variant to use. Defaults to 0
149 unsigned AssemblerDialect;
151 /// This is true if the assembler allows @ characters in symbol names.
152 /// Defaults to false.
155 /// This is true if data region markers should be printed as
156 /// ".data_region/.end_data_region" directives. If false, use "$d/$a" labels
158 bool UseDataRegionDirectives;
160 //===--- Data Emission Directives -------------------------------------===//
162 /// This should be set to the directive used to get some number of zero bytes
163 /// emitted to the current section. Common cases are "\t.zero\t" and
164 /// "\t.space\t". If this is set to null, the Data*bitsDirective's will be
165 /// used to emit zero bytes. Defaults to "\t.zero\t"
166 const char *ZeroDirective;
168 /// This directive allows emission of an ascii string with the standard C
169 /// escape characters embedded into it. Defaults to "\t.ascii\t"
170 const char *AsciiDirective;
172 /// If not null, this allows for special handling of zero terminated strings
173 /// on this target. This is commonly supported as ".asciz". If a target
174 /// doesn't support this, it can be set to null. Defaults to "\t.asciz\t"
175 const char *AscizDirective;
177 /// These directives are used to output some unit of integer data to the
178 /// current section. If a data directive is set to null, smaller data
179 /// directives will be used to emit the large sizes. Defaults to "\t.byte\t",
180 /// "\t.short\t", "\t.long\t", "\t.quad\t"
181 const char *Data8bitsDirective;
182 const char *Data16bitsDirective;
183 const char *Data32bitsDirective;
184 const char *Data64bitsDirective;
186 /// If non-null, a directive that is used to emit a word which should be
187 /// relocated as a 64-bit GP-relative offset, e.g. .gpdword on Mips. Defaults
189 const char *GPRel64Directive;
191 /// If non-null, a directive that is used to emit a word which should be
192 /// relocated as a 32-bit GP-relative offset, e.g. .gpword on Mips or .gprel32
193 /// on Alpha. Defaults to NULL.
194 const char *GPRel32Directive;
196 /// This is true if this target uses "Sun Style" syntax for section switching
197 /// ("#alloc,#write" etc) instead of the normal ELF syntax (,"a,w") in
198 /// .section directives. Defaults to false.
199 bool SunStyleELFSectionSwitchSyntax;
201 /// This is true if this target uses ELF '.section' directive before the
202 /// '.bss' one. It's used for PPC/Linux which doesn't support the '.bss'
203 /// directive only. Defaults to false.
204 bool UsesELFSectionDirectiveForBSS;
206 bool NeedsDwarfSectionOffsetDirective;
208 //===--- Alignment Information ----------------------------------------===//
210 /// If this is true (the default) then the asmprinter emits ".align N"
211 /// directives, where N is the number of bytes to align to. Otherwise, it
212 /// emits ".align log2(N)", e.g. 3 to align to an 8 byte boundary. Defaults
214 bool AlignmentIsInBytes;
216 /// If non-zero, this is used to fill the executable space created as the
217 /// result of a alignment directive. Defaults to 0
218 unsigned TextAlignFillValue;
220 //===--- Global Variable Emission Directives --------------------------===//
222 /// This is the directive used to declare a global entity. Defaults to
224 const char *GlobalDirective;
226 /// True if the expression
228 /// uses an relocation but it can be supressed by writting
231 bool SetDirectiveSuppressesReloc;
233 /// False if the assembler requires that we use
245 /// Defaults to true.
246 bool HasAggressiveSymbolFolding;
248 /// True is .comm's and .lcomms optional alignment is to be specified in bytes
249 /// instead of log2(n). Defaults to true.
250 bool COMMDirectiveAlignmentIsInBytes;
252 /// Describes if the .lcomm directive for the target supports an alignment
253 /// argument and how it is interpreted. Defaults to NoAlignment.
254 LCOMM::LCOMMType LCOMMDirectiveAlignmentType;
256 /// True if the target has .type and .size directives, this is true for most
257 /// ELF targets. Defaults to true.
258 bool HasDotTypeDotSizeDirective;
260 /// True if the target has a single parameter .file directive, this is true
261 /// for ELF targets. Defaults to true.
262 bool HasSingleParameterDotFile;
264 /// True if the target has a .ident directive, this is true for ELF targets.
265 /// Defaults to false.
266 bool HasIdentDirective;
268 /// True if this target supports the MachO .no_dead_strip directive. Defaults
272 /// Used to declare a global as being a weak symbol. Defaults to ".weak".
273 const char *WeakDirective;
275 /// This directive, if non-null, is used to declare a global as being a weak
276 /// undefined symbol. Defaults to NULL.
277 const char *WeakRefDirective;
279 /// True if we have a directive to declare a global as being a weak defined
280 /// symbol. Defaults to false.
281 bool HasWeakDefDirective;
283 /// True if we have a directive to declare a global as being a weak defined
284 /// symbol that can be hidden (unexported). Defaults to false.
285 bool HasWeakDefCanBeHiddenDirective;
287 /// True if we have a .linkonce directive. This is used on cygwin/mingw.
288 /// Defaults to false.
289 bool HasLinkOnceDirective;
291 /// This attribute, if not MCSA_Invalid, is used to declare a symbol as having
292 /// hidden visibility. Defaults to MCSA_Hidden.
293 MCSymbolAttr HiddenVisibilityAttr;
295 /// This attribute, if not MCSA_Invalid, is used to declare an undefined
296 /// symbol as having hidden visibility. Defaults to MCSA_Hidden.
297 MCSymbolAttr HiddenDeclarationVisibilityAttr;
299 /// This attribute, if not MCSA_Invalid, is used to declare a symbol as having
300 /// protected visibility. Defaults to MCSA_Protected
301 MCSymbolAttr ProtectedVisibilityAttr;
303 //===--- Dwarf Emission Directives -----------------------------------===//
305 /// True if target supports emission of debugging information. Defaults to
307 bool SupportsDebugInformation;
309 /// Exception handling format for the target. Defaults to None.
310 ExceptionHandling ExceptionsType;
312 /// Windows exception handling data (.pdata) encoding. Defaults to Invalid.
313 WinEH::EncodingType WinEHEncodingType;
315 /// True if Dwarf2 output generally uses relocations for references to other
316 /// .debug_* sections.
317 bool DwarfUsesRelocationsAcrossSections;
319 /// True if DWARF FDE symbol reference relocations should be replaced by an
320 /// absolute difference.
321 bool DwarfFDESymbolsUseAbsDiff;
323 /// True if dwarf register numbers are printed instead of symbolic register
324 /// names in .cfi_* directives. Defaults to false.
325 bool DwarfRegNumForCFI;
327 /// True if target uses parens to indicate the symbol variant instead of @.
328 /// For example, foo(plt) instead of foo@plt. Defaults to false.
329 bool UseParensForSymbolVariant;
331 //===--- Prologue State ----------------------------------------------===//
333 std::vector<MCCFIInstruction> InitialFrameState;
335 //===--- Integrated Assembler State ----------------------------------===//
337 /// Should we use the integrated assembler?
338 /// The integrated assembler should be enabled by default (by the
339 /// constructors) when failing to parse a valid piece of assembly (inline
340 /// or otherwise) is considered a bug. It may then be overridden after
341 /// construction (see LLVMTargetMachine::initAsmInfo()).
342 bool UseIntegratedAssembler;
344 /// Compress DWARF debug sections. Defaults to false.
345 bool CompressDebugSections;
348 explicit MCAsmInfo();
349 virtual ~MCAsmInfo();
351 /// Get the pointer size in bytes.
352 unsigned getPointerSize() const { return PointerSize; }
354 /// Get the callee-saved register stack slot
356 unsigned getCalleeSaveStackSlotSize() const {
357 return CalleeSaveStackSlotSize;
360 /// True if the target is little endian.
361 bool isLittleEndian() const { return IsLittleEndian; }
363 /// True if target stack grow up.
364 bool isStackGrowthDirectionUp() const { return StackGrowsUp; }
366 bool hasSubsectionsViaSymbols() const { return HasSubsectionsViaSymbols; }
368 // Data directive accessors.
370 const char *getData8bitsDirective() const { return Data8bitsDirective; }
371 const char *getData16bitsDirective() const { return Data16bitsDirective; }
372 const char *getData32bitsDirective() const { return Data32bitsDirective; }
373 const char *getData64bitsDirective() const { return Data64bitsDirective; }
374 const char *getGPRel64Directive() const { return GPRel64Directive; }
375 const char *getGPRel32Directive() const { return GPRel32Directive; }
377 /// Targets can implement this method to specify a section to switch to if the
378 /// translation unit doesn't have any trampolines that require an executable
380 virtual const MCSection *getNonexecutableStackSection(MCContext &Ctx) const {
384 /// \brief True if the section is atomized using the symbols in it.
385 /// This is false if the section is not atomized at all (most ELF sections) or
386 /// if it is atomized based on its contents (MachO' __TEXT,__cstring for
388 virtual bool isSectionAtomizableBySymbols(const MCSection &Section) const;
390 virtual const MCExpr *getExprForPersonalitySymbol(const MCSymbol *Sym,
392 MCStreamer &Streamer) const;
394 virtual const MCExpr *getExprForFDESymbol(const MCSymbol *Sym,
396 MCStreamer &Streamer) const;
398 bool usesSunStyleELFSectionSwitchSyntax() const {
399 return SunStyleELFSectionSwitchSyntax;
402 bool usesELFSectionDirectiveForBSS() const {
403 return UsesELFSectionDirectiveForBSS;
406 bool needsDwarfSectionOffsetDirective() const {
407 return NeedsDwarfSectionOffsetDirective;
412 bool hasMachoZeroFillDirective() const { return HasMachoZeroFillDirective; }
413 bool hasMachoTBSSDirective() const { return HasMachoTBSSDirective; }
414 bool hasStaticCtorDtorReferenceInStaticMode() const {
415 return HasStaticCtorDtorReferenceInStaticMode;
417 unsigned getMaxInstLength() const { return MaxInstLength; }
418 unsigned getMinInstAlignment() const { return MinInstAlignment; }
419 bool getDollarIsPC() const { return DollarIsPC; }
420 const char *getSeparatorString() const { return SeparatorString; }
422 /// This indicates the column (zero-based) at which asm comments should be
424 unsigned getCommentColumn() const { return 40; }
426 const char *getCommentString() const { return CommentString; }
427 const char *getLabelSuffix() const { return LabelSuffix; }
429 bool useAssignmentForEHBegin() const { return UseAssignmentForEHBegin; }
430 const char *getPrivateGlobalPrefix() const { return PrivateGlobalPrefix; }
431 const char *getPrivateLabelPrefix() const { return PrivateLabelPrefix; }
432 bool hasLinkerPrivateGlobalPrefix() const {
433 return LinkerPrivateGlobalPrefix[0] != '\0';
435 const char *getLinkerPrivateGlobalPrefix() const {
436 if (hasLinkerPrivateGlobalPrefix())
437 return LinkerPrivateGlobalPrefix;
438 return getPrivateGlobalPrefix();
440 const char *getInlineAsmStart() const { return InlineAsmStart; }
441 const char *getInlineAsmEnd() const { return InlineAsmEnd; }
442 const char *getCode16Directive() const { return Code16Directive; }
443 const char *getCode32Directive() const { return Code32Directive; }
444 const char *getCode64Directive() const { return Code64Directive; }
445 unsigned getAssemblerDialect() const { return AssemblerDialect; }
446 bool doesAllowAtInName() const { return AllowAtInName; }
447 bool doesSupportDataRegionDirectives() const {
448 return UseDataRegionDirectives;
450 const char *getZeroDirective() const { return ZeroDirective; }
451 const char *getAsciiDirective() const { return AsciiDirective; }
452 const char *getAscizDirective() const { return AscizDirective; }
453 bool getAlignmentIsInBytes() const { return AlignmentIsInBytes; }
454 unsigned getTextAlignFillValue() const { return TextAlignFillValue; }
455 const char *getGlobalDirective() const { return GlobalDirective; }
456 bool doesSetDirectiveSuppressesReloc() const {
457 return SetDirectiveSuppressesReloc;
459 bool hasAggressiveSymbolFolding() const { return HasAggressiveSymbolFolding; }
460 bool getCOMMDirectiveAlignmentIsInBytes() const {
461 return COMMDirectiveAlignmentIsInBytes;
463 LCOMM::LCOMMType getLCOMMDirectiveAlignmentType() const {
464 return LCOMMDirectiveAlignmentType;
466 bool hasDotTypeDotSizeDirective() const { return HasDotTypeDotSizeDirective; }
467 bool hasSingleParameterDotFile() const { return HasSingleParameterDotFile; }
468 bool hasIdentDirective() const { return HasIdentDirective; }
469 bool hasNoDeadStrip() const { return HasNoDeadStrip; }
470 const char *getWeakDirective() const { return WeakDirective; }
471 const char *getWeakRefDirective() const { return WeakRefDirective; }
472 bool hasWeakDefDirective() const { return HasWeakDefDirective; }
473 bool hasWeakDefCanBeHiddenDirective() const {
474 return HasWeakDefCanBeHiddenDirective;
476 bool hasLinkOnceDirective() const { return HasLinkOnceDirective; }
478 MCSymbolAttr getHiddenVisibilityAttr() const { return HiddenVisibilityAttr; }
479 MCSymbolAttr getHiddenDeclarationVisibilityAttr() const {
480 return HiddenDeclarationVisibilityAttr;
482 MCSymbolAttr getProtectedVisibilityAttr() const {
483 return ProtectedVisibilityAttr;
485 bool doesSupportDebugInformation() const { return SupportsDebugInformation; }
486 bool doesSupportExceptionHandling() const {
487 return ExceptionsType != ExceptionHandling::None;
489 ExceptionHandling getExceptionHandlingType() const { return ExceptionsType; }
490 WinEH::EncodingType getWinEHEncodingType() const { return WinEHEncodingType; }
492 /// Returns true if the exception handling method for the platform uses call
493 /// frame information to unwind.
494 bool usesCFIForEH() const {
495 return (ExceptionsType == ExceptionHandling::DwarfCFI ||
496 ExceptionsType == ExceptionHandling::ARM ||
497 ExceptionsType == ExceptionHandling::WinEH);
500 bool usesWindowsCFI() const {
501 return ExceptionsType == ExceptionHandling::WinEH;
504 bool doesDwarfUseRelocationsAcrossSections() const {
505 return DwarfUsesRelocationsAcrossSections;
507 bool doDwarfFDESymbolsUseAbsDiff() const { return DwarfFDESymbolsUseAbsDiff; }
508 bool useDwarfRegNumForCFI() const { return DwarfRegNumForCFI; }
509 bool useParensForSymbolVariant() const { return UseParensForSymbolVariant; }
511 void addInitialFrameState(const MCCFIInstruction &Inst) {
512 InitialFrameState.push_back(Inst);
515 const std::vector<MCCFIInstruction> &getInitialFrameState() const {
516 return InitialFrameState;
519 /// Return true if assembly (inline or otherwise) should be parsed.
520 bool useIntegratedAssembler() const { return UseIntegratedAssembler; }
522 /// Set whether assembly (inline or otherwise) should be parsed.
523 virtual void setUseIntegratedAssembler(bool Value) {
524 UseIntegratedAssembler = Value;
527 bool compressDebugSections() const { return CompressDebugSections; }
529 void setCompressDebugSections(bool CompressDebugSections) {
530 this->CompressDebugSections = CompressDebugSections;