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 {
34 ET_Invalid, /// Invalid
35 ET_Alpha, /// Windows Alpha
36 ET_Alpha64, /// Windows AXP64
37 ET_ARM, /// Windows NT (Windows on ARM)
38 ET_CE, /// Windows CE ARM, PowerPC, SH3, SH4
39 ET_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 a static ctor/dtor
91 /// list. This directive is only emitted in Static relocation model. Default
93 bool HasStaticCtorDtorReferenceInStaticMode;
95 /// True if the linker has a bug and requires that the debug_line section be
96 /// of a minimum size. In practice such a linker requires a non-empty line
97 /// sequence if a file is present. Default to false.
98 bool LinkerRequiresNonEmptyDwarfLines;
100 /// This is the maximum possible length of an instruction, which is needed to
101 /// compute the size of an inline asm. Defaults to 4.
102 unsigned MaxInstLength;
104 /// Every possible instruction length is a multiple of this value. Factored
105 /// out in .debug_frame and .debug_line. Defaults to 1.
106 unsigned MinInstAlignment;
108 /// The '$' token, when not referencing an identifier or constant, refers to
109 /// the current PC. Defaults to false.
112 /// This string, if specified, is used to separate instructions from each
113 /// other when on the same line. Defaults to ';'
114 const char *SeparatorString;
116 /// This indicates the comment character used by the assembler. Defaults to
118 const char *CommentString;
120 /// This is appended to emitted labels. Defaults to ":"
121 const char *LabelSuffix;
123 // Print the EH begin symbol with an assignment. Defaults to false.
124 bool UseAssignmentForEHBegin;
126 /// This prefix is used for globals like constant pool entries that are
127 /// completely private to the .s file and should not have names in the .o
128 /// file. Defaults to "L"
129 const char *PrivateGlobalPrefix;
131 /// This prefix is used for symbols that should be passed through the
132 /// assembler but be removed by the linker. This is 'l' on Darwin, currently
133 /// used for some ObjC metadata. The default of "" meast that for this system
134 /// a plain private symbol should be used. Defaults to "".
135 const char *LinkerPrivateGlobalPrefix;
137 /// If these are nonempty, they contain a directive to emit before and after
138 /// an inline assembly statement. Defaults to "#APP\n", "#NO_APP\n"
139 const char *InlineAsmStart;
140 const char *InlineAsmEnd;
142 /// These are assembly directives that tells the assembler to interpret the
143 /// following instructions differently. Defaults to ".code16", ".code32",
145 const char *Code16Directive;
146 const char *Code32Directive;
147 const char *Code64Directive;
149 /// Which dialect of an assembler variant to use. Defaults to 0
150 unsigned AssemblerDialect;
152 /// This is true if the assembler allows @ characters in symbol names.
153 /// Defaults to false.
156 /// This is true if data region markers should be printed as
157 /// ".data_region/.end_data_region" directives. If false, use "$d/$a" labels
159 bool UseDataRegionDirectives;
161 //===--- Data Emission Directives -------------------------------------===//
163 /// This should be set to the directive used to get some number of zero bytes
164 /// emitted to the current section. Common cases are "\t.zero\t" and
165 /// "\t.space\t". If this is set to null, the Data*bitsDirective's will be
166 /// used to emit zero bytes. Defaults to "\t.zero\t"
167 const char *ZeroDirective;
169 /// This directive allows emission of an ascii string with the standard C
170 /// escape characters embedded into it. Defaults to "\t.ascii\t"
171 const char *AsciiDirective;
173 /// If not null, this allows for special handling of zero terminated strings
174 /// on this target. This is commonly supported as ".asciz". If a target
175 /// doesn't support this, it can be set to null. Defaults to "\t.asciz\t"
176 const char *AscizDirective;
178 /// These directives are used to output some unit of integer data to the
179 /// current section. If a data directive is set to null, smaller data
180 /// directives will be used to emit the large sizes. Defaults to "\t.byte\t",
181 /// "\t.short\t", "\t.long\t", "\t.quad\t"
182 const char *Data8bitsDirective;
183 const char *Data16bitsDirective;
184 const char *Data32bitsDirective;
185 const char *Data64bitsDirective;
187 /// If non-null, a directive that is used to emit a word which should be
188 /// relocated as a 64-bit GP-relative offset, e.g. .gpdword on Mips. Defaults
190 const char *GPRel64Directive;
192 /// If non-null, a directive that is used to emit a word which should be
193 /// relocated as a 32-bit GP-relative offset, e.g. .gpword on Mips or .gprel32
194 /// on Alpha. Defaults to NULL.
195 const char *GPRel32Directive;
197 /// This is true if this target uses "Sun Style" syntax for section switching
198 /// ("#alloc,#write" etc) instead of the normal ELF syntax (,"a,w") in
199 /// .section directives. Defaults to false.
200 bool SunStyleELFSectionSwitchSyntax;
202 /// This is true if this target uses ELF '.section' directive before the
203 /// '.bss' one. It's used for PPC/Linux which doesn't support the '.bss'
204 /// directive only. Defaults to false.
205 bool UsesELFSectionDirectiveForBSS;
207 bool NeedsDwarfSectionOffsetDirective;
209 //===--- Alignment Information ----------------------------------------===//
211 /// If this is true (the default) then the asmprinter emits ".align N"
212 /// directives, where N is the number of bytes to align to. Otherwise, it
213 /// emits ".align log2(N)", e.g. 3 to align to an 8 byte boundary. Defaults
215 bool AlignmentIsInBytes;
217 /// If non-zero, this is used to fill the executable space created as the
218 /// result of a alignment directive. Defaults to 0
219 unsigned TextAlignFillValue;
221 //===--- Global Variable Emission Directives --------------------------===//
223 /// This is the directive used to declare a global entity. Defaults to NULL.
224 const char *GlobalDirective;
226 /// True if the assembler supports the .set directive. Defaults to true.
227 bool HasSetDirective;
229 /// False if the assembler requires that we use
241 /// Defaults to true.
242 bool HasAggressiveSymbolFolding;
244 /// True is .comm's and .lcomms optional alignment is to be specified in bytes
245 /// instead of log2(n). Defaults to true.
246 bool COMMDirectiveAlignmentIsInBytes;
248 /// Describes if the .lcomm directive for the target supports an alignment
249 /// argument and how it is interpreted. Defaults to NoAlignment.
250 LCOMM::LCOMMType LCOMMDirectiveAlignmentType;
252 /// True if the target has .type and .size directives, this is true for most
253 /// ELF targets. Defaults to true.
254 bool HasDotTypeDotSizeDirective;
256 /// True if the target has a single parameter .file directive, this is true
257 /// for ELF targets. Defaults to true.
258 bool HasSingleParameterDotFile;
260 /// True if the target has a .ident directive, this is true for ELF targets.
261 /// Defaults to false.
262 bool HasIdentDirective;
264 /// True if this target supports the MachO .no_dead_strip directive. Defaults
268 /// This directive, if non-null, is used to declare a global as being a weak
269 /// undefined symbol. Defaults to NULL.
270 const char *WeakRefDirective;
272 /// True if we have a directive to declare a global as being a weak defined
273 /// symbol. Defaults to false.
274 bool HasWeakDefDirective;
276 /// True if we have a directive to declare a global as being a weak defined
277 /// symbol that can be hidden (unexported). Defaults to false.
278 bool HasWeakDefCanBeHiddenDirective;
280 /// True if we have a .linkonce directive. This is used on cygwin/mingw.
281 /// Defaults to false.
282 bool HasLinkOnceDirective;
284 /// This attribute, if not MCSA_Invalid, is used to declare a symbol as having
285 /// hidden visibility. Defaults to MCSA_Hidden.
286 MCSymbolAttr HiddenVisibilityAttr;
288 /// This attribute, if not MCSA_Invalid, is used to declare an undefined
289 /// symbol as having hidden visibility. Defaults to MCSA_Hidden.
290 MCSymbolAttr HiddenDeclarationVisibilityAttr;
292 /// This attribute, if not MCSA_Invalid, is used to declare a symbol as having
293 /// protected visibility. Defaults to MCSA_Protected
294 MCSymbolAttr ProtectedVisibilityAttr;
296 //===--- Dwarf Emission Directives -----------------------------------===//
298 /// True if target asm supports leb128 directives. Defaults to false.
301 /// True if target supports emission of debugging information. Defaults to
303 bool SupportsDebugInformation;
305 /// Exception handling format for the target. Defaults to None.
306 ExceptionHandling ExceptionsType;
308 /// Windows exception handling data (.pdata) encoding. Defaults to Invalid.
309 WinEH::EncodingType WinEHEncodingType;
311 /// True if Dwarf2 output generally uses relocations for references to other
312 /// .debug_* sections.
313 bool DwarfUsesRelocationsAcrossSections;
315 /// True if DWARF FDE symbol reference relocations should be replaced by an
316 /// absolute difference.
317 bool DwarfFDESymbolsUseAbsDiff;
319 /// True if dwarf register numbers are printed instead of symbolic register
320 /// names in .cfi_* directives. Defaults to false.
321 bool DwarfRegNumForCFI;
323 /// True if target uses parens to indicate the symbol variant instead of @.
324 /// For example, foo(plt) instead of foo@plt. Defaults to false.
325 bool UseParensForSymbolVariant;
327 //===--- Prologue State ----------------------------------------------===//
329 std::vector<MCCFIInstruction> InitialFrameState;
331 //===--- Integrated Assembler State ----------------------------------===//
333 /// Should we use the integrated assembler?
334 /// The integrated assembler should be enabled by default (by the
335 /// constructors) when failing to parse a valid piece of assembly (inline
336 /// or otherwise) is considered a bug. It may then be overridden after
337 /// construction (see LLVMTargetMachine::initAsmInfo()).
338 bool UseIntegratedAssembler;
340 /// Compress DWARF debug sections. Defaults to false.
341 bool CompressDebugSections;
344 explicit MCAsmInfo();
345 virtual ~MCAsmInfo();
347 /// Get the pointer size in bytes.
348 unsigned getPointerSize() const { return PointerSize; }
350 /// Get the callee-saved register stack slot
352 unsigned getCalleeSaveStackSlotSize() const {
353 return CalleeSaveStackSlotSize;
356 /// True if the target is little endian.
357 bool isLittleEndian() const { return IsLittleEndian; }
359 /// True if target stack grow up.
360 bool isStackGrowthDirectionUp() const { return StackGrowsUp; }
362 bool hasSubsectionsViaSymbols() const { return HasSubsectionsViaSymbols; }
364 // Data directive accessors.
366 const char *getData8bitsDirective() const { return Data8bitsDirective; }
367 const char *getData16bitsDirective() const { return Data16bitsDirective; }
368 const char *getData32bitsDirective() const { return Data32bitsDirective; }
369 const char *getData64bitsDirective() const { return Data64bitsDirective; }
370 const char *getGPRel64Directive() const { return GPRel64Directive; }
371 const char *getGPRel32Directive() const { return GPRel32Directive; }
373 /// Targets can implement this method to specify a section to switch to if the
374 /// translation unit doesn't have any trampolines that require an executable
376 virtual const MCSection *getNonexecutableStackSection(MCContext &Ctx) const {
380 virtual const MCExpr *getExprForPersonalitySymbol(const MCSymbol *Sym,
382 MCStreamer &Streamer) const;
384 virtual const MCExpr *getExprForFDESymbol(const MCSymbol *Sym,
386 MCStreamer &Streamer) const;
388 bool usesSunStyleELFSectionSwitchSyntax() const {
389 return SunStyleELFSectionSwitchSyntax;
392 bool usesELFSectionDirectiveForBSS() const {
393 return UsesELFSectionDirectiveForBSS;
396 bool needsDwarfSectionOffsetDirective() const {
397 return NeedsDwarfSectionOffsetDirective;
402 bool hasMachoZeroFillDirective() const { return HasMachoZeroFillDirective; }
403 bool hasMachoTBSSDirective() const { return HasMachoTBSSDirective; }
404 bool hasStaticCtorDtorReferenceInStaticMode() const {
405 return HasStaticCtorDtorReferenceInStaticMode;
407 bool getLinkerRequiresNonEmptyDwarfLines() const {
408 return LinkerRequiresNonEmptyDwarfLines;
410 unsigned getMaxInstLength() const { return MaxInstLength; }
411 unsigned getMinInstAlignment() const { return MinInstAlignment; }
412 bool getDollarIsPC() const { return DollarIsPC; }
413 const char *getSeparatorString() const { return SeparatorString; }
415 /// This indicates the column (zero-based) at which asm comments should be
417 unsigned getCommentColumn() const { return 40; }
419 const char *getCommentString() const { return CommentString; }
420 const char *getLabelSuffix() const { return LabelSuffix; }
422 bool useAssignmentForEHBegin() const { return UseAssignmentForEHBegin; }
423 const char *getPrivateGlobalPrefix() const { return PrivateGlobalPrefix; }
424 bool hasLinkerPrivateGlobalPrefix() const {
425 return LinkerPrivateGlobalPrefix[0] != '\0';
427 const char *getLinkerPrivateGlobalPrefix() const {
428 if (hasLinkerPrivateGlobalPrefix())
429 return LinkerPrivateGlobalPrefix;
430 return getPrivateGlobalPrefix();
432 const char *getInlineAsmStart() const { return InlineAsmStart; }
433 const char *getInlineAsmEnd() const { return InlineAsmEnd; }
434 const char *getCode16Directive() const { return Code16Directive; }
435 const char *getCode32Directive() const { return Code32Directive; }
436 const char *getCode64Directive() const { return Code64Directive; }
437 unsigned getAssemblerDialect() const { return AssemblerDialect; }
438 bool doesAllowAtInName() const { return AllowAtInName; }
439 bool doesSupportDataRegionDirectives() const {
440 return UseDataRegionDirectives;
442 const char *getZeroDirective() const { return ZeroDirective; }
443 const char *getAsciiDirective() const { return AsciiDirective; }
444 const char *getAscizDirective() const { return AscizDirective; }
445 bool getAlignmentIsInBytes() const { return AlignmentIsInBytes; }
446 unsigned getTextAlignFillValue() const { return TextAlignFillValue; }
447 const char *getGlobalDirective() const { return GlobalDirective; }
448 bool hasSetDirective() const { return HasSetDirective; }
449 bool hasAggressiveSymbolFolding() const { return HasAggressiveSymbolFolding; }
450 bool getCOMMDirectiveAlignmentIsInBytes() const {
451 return COMMDirectiveAlignmentIsInBytes;
453 LCOMM::LCOMMType getLCOMMDirectiveAlignmentType() const {
454 return LCOMMDirectiveAlignmentType;
456 bool hasDotTypeDotSizeDirective() const { return HasDotTypeDotSizeDirective; }
457 bool hasSingleParameterDotFile() const { return HasSingleParameterDotFile; }
458 bool hasIdentDirective() const { return HasIdentDirective; }
459 bool hasNoDeadStrip() const { return HasNoDeadStrip; }
460 const char *getWeakRefDirective() const { return WeakRefDirective; }
461 bool hasWeakDefDirective() const { return HasWeakDefDirective; }
462 bool hasWeakDefCanBeHiddenDirective() const {
463 return HasWeakDefCanBeHiddenDirective;
465 bool hasLinkOnceDirective() const { return HasLinkOnceDirective; }
467 MCSymbolAttr getHiddenVisibilityAttr() const { return HiddenVisibilityAttr; }
468 MCSymbolAttr getHiddenDeclarationVisibilityAttr() const {
469 return HiddenDeclarationVisibilityAttr;
471 MCSymbolAttr getProtectedVisibilityAttr() const {
472 return ProtectedVisibilityAttr;
474 bool hasLEB128() const { return HasLEB128; }
475 bool doesSupportDebugInformation() const { return SupportsDebugInformation; }
476 bool doesSupportExceptionHandling() const {
477 return ExceptionsType != ExceptionHandling::None;
479 ExceptionHandling getExceptionHandlingType() const { return ExceptionsType; }
480 WinEH::EncodingType getWinEHEncodingType() const { return WinEHEncodingType; }
481 bool isExceptionHandlingDwarf() const {
482 return (ExceptionsType == ExceptionHandling::DwarfCFI ||
483 ExceptionsType == ExceptionHandling::ARM ||
484 // Windows handler data still uses DWARF LSDA encoding.
485 ExceptionsType == ExceptionHandling::WinEH);
487 bool doesDwarfUseRelocationsAcrossSections() const {
488 return DwarfUsesRelocationsAcrossSections;
490 bool doDwarfFDESymbolsUseAbsDiff() const { return DwarfFDESymbolsUseAbsDiff; }
491 bool useDwarfRegNumForCFI() const { return DwarfRegNumForCFI; }
492 bool useParensForSymbolVariant() const { return UseParensForSymbolVariant; }
494 void addInitialFrameState(const MCCFIInstruction &Inst) {
495 InitialFrameState.push_back(Inst);
498 const std::vector<MCCFIInstruction> &getInitialFrameState() const {
499 return InitialFrameState;
502 /// Return true if assembly (inline or otherwise) should be parsed.
503 bool useIntegratedAssembler() const { return UseIntegratedAssembler; }
505 /// Set whether assembly (inline or otherwise) should be parsed.
506 virtual void setUseIntegratedAssembler(bool Value) {
507 UseIntegratedAssembler = Value;
510 bool compressDebugSections() const { return CompressDebugSections; }
512 void setCompressDebugSections(bool CompressDebugSections) {
513 this->CompressDebugSections = CompressDebugSections;