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 namespace ExceptionHandling {
45 enum ExceptionsType { None, DwarfCFI, SjLj, ARM, Win64 };
49 enum LCOMMType { NoAlignment, ByteAlignment, Log2Alignment };
52 /// This class is intended to be used as a base class for asm
53 /// properties and features specific to the target.
56 //===------------------------------------------------------------------===//
57 // Properties to be set by the target writer, used to configure asm printer.
60 /// Pointer size in bytes. Default is 4.
63 /// Size of the stack slot reserved for callee-saved registers, in bytes.
64 /// Default is same as pointer size.
65 unsigned CalleeSaveStackSlotSize;
67 /// True if target is little endian. Default is true.
70 /// True if target stack grow up. Default is false.
73 /// True if this target has the MachO .subsections_via_symbols directive.
75 bool HasSubsectionsViaSymbols;
77 /// True if this is a MachO target that supports the macho-specific .zerofill
78 /// directive for emitting BSS Symbols. Default is false.
79 bool HasMachoZeroFillDirective;
81 /// True if this is a MachO target that supports the macho-specific .tbss
82 /// directive for emitting thread local BSS Symbols. Default is false.
83 bool HasMachoTBSSDirective;
85 /// True if the compiler should emit a ".reference .constructors_used" or
86 /// ".reference .destructors_used" directive after the a static ctor/dtor
87 /// list. This directive is only emitted in Static relocation model. Default
89 bool HasStaticCtorDtorReferenceInStaticMode;
91 /// True if the linker has a bug and requires that the debug_line section be
92 /// of a minimum size. In practice such a linker requires a non-empty line
93 /// sequence if a file is present. Default to false.
94 bool LinkerRequiresNonEmptyDwarfLines;
96 /// This is the maximum possible length of an instruction, which is needed to
97 /// compute the size of an inline asm. Defaults to 4.
98 unsigned MaxInstLength;
100 /// Every possible instruction length is a multiple of this value. Factored
101 /// out in .debug_frame and .debug_line. Defaults to 1.
102 unsigned MinInstAlignment;
104 /// The '$' token, when not referencing an identifier or constant, refers to
105 /// the current PC. Defaults to false.
108 /// This string, if specified, is used to separate instructions from each
109 /// other when on the same line. Defaults to ';'
110 const char *SeparatorString;
112 /// This indicates the comment character used by the assembler. Defaults to
114 const char *CommentString;
116 /// This is appended to emitted labels. Defaults to ":"
117 const char *LabelSuffix;
119 /// This is appended to emitted labels. Defaults to ":"
120 const char *DebugLabelSuffix;
122 /// This prefix is used for globals like constant pool entries that are
123 /// completely private to the .s file and should not have names in the .o
124 /// file. Defaults to "L"
125 const char *PrivateGlobalPrefix;
127 /// This prefix is used for symbols that should be passed through the
128 /// assembler but be removed by the linker. This is 'l' on Darwin, currently
129 /// used for some ObjC metadata. The default of "" meast that for this system
130 /// a plain private symbol should be used. Defaults to "".
131 const char *LinkerPrivateGlobalPrefix;
133 /// If these are nonempty, they contain a directive to emit before and after
134 /// an inline assembly statement. Defaults to "#APP\n", "#NO_APP\n"
135 const char *InlineAsmStart;
136 const char *InlineAsmEnd;
138 /// These are assembly directives that tells the assembler to interpret the
139 /// following instructions differently. Defaults to ".code16", ".code32",
141 const char *Code16Directive;
142 const char *Code32Directive;
143 const char *Code64Directive;
145 /// Which dialect of an assembler variant to use. Defaults to 0
146 unsigned AssemblerDialect;
148 /// This is true if the assembler allows @ characters in symbol names.
149 /// Defaults to false.
152 /// This is true if data region markers should be printed as
153 /// ".data_region/.end_data_region" directives. If false, use "$d/$a" labels
155 bool UseDataRegionDirectives;
157 //===--- Data Emission Directives -------------------------------------===//
159 /// This should be set to the directive used to get some number of zero bytes
160 /// emitted to the current section. Common cases are "\t.zero\t" and
161 /// "\t.space\t". If this is set to null, the Data*bitsDirective's will be
162 /// used to emit zero bytes. Defaults to "\t.zero\t"
163 const char *ZeroDirective;
165 /// This directive allows emission of an ascii string with the standard C
166 /// escape characters embedded into it. Defaults to "\t.ascii\t"
167 const char *AsciiDirective;
169 /// If not null, this allows for special handling of zero terminated strings
170 /// on this target. This is commonly supported as ".asciz". If a target
171 /// doesn't support this, it can be set to null. Defaults to "\t.asciz\t"
172 const char *AscizDirective;
174 /// These directives are used to output some unit of integer data to the
175 /// current section. If a data directive is set to null, smaller data
176 /// directives will be used to emit the large sizes. Defaults to "\t.byte\t",
177 /// "\t.short\t", "\t.long\t", "\t.quad\t"
178 const char *Data8bitsDirective;
179 const char *Data16bitsDirective;
180 const char *Data32bitsDirective;
181 const char *Data64bitsDirective;
183 /// If non-null, a directive that is used to emit a word which should be
184 /// relocated as a 64-bit GP-relative offset, e.g. .gpdword on Mips. Defaults
186 const char *GPRel64Directive;
188 /// If non-null, a directive that is used to emit a word which should be
189 /// relocated as a 32-bit GP-relative offset, e.g. .gpword on Mips or .gprel32
190 /// on Alpha. Defaults to NULL.
191 const char *GPRel32Directive;
193 /// This is true if this target uses "Sun Style" syntax for section switching
194 /// ("#alloc,#write" etc) instead of the normal ELF syntax (,"a,w") in
195 /// .section directives. Defaults to false.
196 bool SunStyleELFSectionSwitchSyntax;
198 /// This is true if this target uses ELF '.section' directive before the
199 /// '.bss' one. It's used for PPC/Linux which doesn't support the '.bss'
200 /// directive only. Defaults to false.
201 bool UsesELFSectionDirectiveForBSS;
203 bool NeedsDwarfSectionOffsetDirective;
205 //===--- Alignment Information ----------------------------------------===//
207 /// If this is true (the default) then the asmprinter emits ".align N"
208 /// directives, where N is the number of bytes to align to. Otherwise, it
209 /// emits ".align log2(N)", e.g. 3 to align to an 8 byte boundary. Defaults
211 bool AlignmentIsInBytes;
213 /// If non-zero, this is used to fill the executable space created as the
214 /// result of a alignment directive. Defaults to 0
215 unsigned TextAlignFillValue;
217 //===--- Global Variable Emission Directives --------------------------===//
219 /// This is the directive used to declare a global entity. Defaults to NULL.
220 const char *GlobalDirective;
222 /// True if the assembler supports the .set directive. Defaults to true.
223 bool HasSetDirective;
225 /// False if the assembler requires that we use
237 /// Defaults to true.
238 bool HasAggressiveSymbolFolding;
240 /// True is .comm's and .lcomms optional alignment is to be specified in bytes
241 /// instead of log2(n). Defaults to true.
242 bool COMMDirectiveAlignmentIsInBytes;
244 /// Describes if the .lcomm directive for the target supports an alignment
245 /// argument and how it is interpreted. Defaults to NoAlignment.
246 LCOMM::LCOMMType LCOMMDirectiveAlignmentType;
248 /// True if the target has .type and .size directives, this is true for most
249 /// ELF targets. Defaults to true.
250 bool HasDotTypeDotSizeDirective;
252 /// True if the target has a single parameter .file directive, this is true
253 /// for ELF targets. Defaults to true.
254 bool HasSingleParameterDotFile;
256 /// True if the target has a .ident directive, this is true for ELF targets.
257 /// Defaults to false.
258 bool HasIdentDirective;
260 /// True if this target supports the MachO .no_dead_strip directive. Defaults
264 /// This directive, if non-null, is used to declare a global as being a weak
265 /// undefined symbol. Defaults to NULL.
266 const char *WeakRefDirective;
268 /// True if we have a directive to declare a global as being a weak defined
269 /// symbol. Defaults to false.
270 bool HasWeakDefDirective;
272 /// True if we have a directive to declare a global as being a weak defined
273 /// symbol that can be hidden (unexported). Defaults to false.
274 bool HasWeakDefCanBeHiddenDirective;
276 /// True if we have a .linkonce directive. This is used on cygwin/mingw.
277 /// Defaults to false.
278 bool HasLinkOnceDirective;
280 /// This attribute, if not MCSA_Invalid, is used to declare a symbol as having
281 /// hidden visibility. Defaults to MCSA_Hidden.
282 MCSymbolAttr HiddenVisibilityAttr;
284 /// This attribute, if not MCSA_Invalid, is used to declare an undefined
285 /// symbol as having hidden visibility. Defaults to MCSA_Hidden.
286 MCSymbolAttr HiddenDeclarationVisibilityAttr;
288 /// This attribute, if not MCSA_Invalid, is used to declare a symbol as having
289 /// protected visibility. Defaults to MCSA_Protected
290 MCSymbolAttr ProtectedVisibilityAttr;
292 //===--- Dwarf Emission Directives -----------------------------------===//
294 /// True if target asm supports leb128 directives. Defaults to false.
297 /// True if target supports emission of debugging information. Defaults to
299 bool SupportsDebugInformation;
301 /// Exception handling format for the target. Defaults to None.
302 ExceptionHandling::ExceptionsType ExceptionsType;
304 /// Windows exception handling data (.pdata) encoding. Defaults to Invalid.
305 WinEH::EncodingType WinEHEncodingType;
307 /// True if Dwarf2 output generally uses relocations for references to other
308 /// .debug_* sections.
309 bool DwarfUsesRelocationsAcrossSections;
311 /// True if DWARF FDE symbol reference relocations should be replaced by an
312 /// absolute difference.
313 bool DwarfFDESymbolsUseAbsDiff;
315 /// True if dwarf register numbers are printed instead of symbolic register
316 /// names in .cfi_* directives. Defaults to false.
317 bool DwarfRegNumForCFI;
319 /// True if target uses parens to indicate the symbol variant instead of @.
320 /// For example, foo(plt) instead of foo@plt. Defaults to false.
321 bool UseParensForSymbolVariant;
323 //===--- Prologue State ----------------------------------------------===//
325 std::vector<MCCFIInstruction> InitialFrameState;
327 //===--- Integrated Assembler State ----------------------------------===//
329 /// Should we use the integrated assembler?
330 /// The integrated assembler should be enabled by default (by the
331 /// constructors) when failing to parse a valid piece of assembly (inline
332 /// or otherwise) is considered a bug. It may then be overridden after
333 /// construction (see LLVMTargetMachine::initAsmInfo()).
334 bool UseIntegratedAssembler;
336 /// Compress DWARF debug sections. Defaults to false.
337 bool CompressDebugSections;
340 explicit MCAsmInfo();
341 virtual ~MCAsmInfo();
343 /// Get the pointer size in bytes.
344 unsigned getPointerSize() const { return PointerSize; }
346 /// Get the callee-saved register stack slot
348 unsigned getCalleeSaveStackSlotSize() const {
349 return CalleeSaveStackSlotSize;
352 /// True if the target is little endian.
353 bool isLittleEndian() const { return IsLittleEndian; }
355 /// True if target stack grow up.
356 bool isStackGrowthDirectionUp() const { return StackGrowsUp; }
358 bool hasSubsectionsViaSymbols() const { return HasSubsectionsViaSymbols; }
360 // Data directive accessors.
362 const char *getData8bitsDirective() const { return Data8bitsDirective; }
363 const char *getData16bitsDirective() const { return Data16bitsDirective; }
364 const char *getData32bitsDirective() const { return Data32bitsDirective; }
365 const char *getData64bitsDirective() const { return Data64bitsDirective; }
366 const char *getGPRel64Directive() const { return GPRel64Directive; }
367 const char *getGPRel32Directive() const { return GPRel32Directive; }
369 /// Targets can implement this method to specify a section to switch to if the
370 /// translation unit doesn't have any trampolines that require an executable
372 virtual const MCSection *getNonexecutableStackSection(MCContext &Ctx) const {
376 virtual const MCExpr *getExprForPersonalitySymbol(const MCSymbol *Sym,
378 MCStreamer &Streamer) const;
380 virtual const MCExpr *getExprForFDESymbol(const MCSymbol *Sym,
382 MCStreamer &Streamer) const;
384 bool usesSunStyleELFSectionSwitchSyntax() const {
385 return SunStyleELFSectionSwitchSyntax;
388 bool usesELFSectionDirectiveForBSS() const {
389 return UsesELFSectionDirectiveForBSS;
392 bool needsDwarfSectionOffsetDirective() const {
393 return NeedsDwarfSectionOffsetDirective;
398 bool hasMachoZeroFillDirective() const { return HasMachoZeroFillDirective; }
399 bool hasMachoTBSSDirective() const { return HasMachoTBSSDirective; }
400 bool hasStaticCtorDtorReferenceInStaticMode() const {
401 return HasStaticCtorDtorReferenceInStaticMode;
403 bool getLinkerRequiresNonEmptyDwarfLines() const {
404 return LinkerRequiresNonEmptyDwarfLines;
406 unsigned getMaxInstLength() const { return MaxInstLength; }
407 unsigned getMinInstAlignment() const { return MinInstAlignment; }
408 bool getDollarIsPC() const { return DollarIsPC; }
409 const char *getSeparatorString() const { return SeparatorString; }
411 /// This indicates the column (zero-based) at which asm comments should be
413 unsigned getCommentColumn() const { return 40; }
415 const char *getCommentString() const { return CommentString; }
416 const char *getLabelSuffix() const { return LabelSuffix; }
418 const char *getDebugLabelSuffix() const { return DebugLabelSuffix; }
419 const char *getPrivateGlobalPrefix() const { return PrivateGlobalPrefix; }
420 bool hasLinkerPrivateGlobalPrefix() const {
421 return LinkerPrivateGlobalPrefix[0] != '\0';
423 const char *getLinkerPrivateGlobalPrefix() const {
424 if (hasLinkerPrivateGlobalPrefix())
425 return LinkerPrivateGlobalPrefix;
426 return getPrivateGlobalPrefix();
428 const char *getInlineAsmStart() const { return InlineAsmStart; }
429 const char *getInlineAsmEnd() const { return InlineAsmEnd; }
430 const char *getCode16Directive() const { return Code16Directive; }
431 const char *getCode32Directive() const { return Code32Directive; }
432 const char *getCode64Directive() const { return Code64Directive; }
433 unsigned getAssemblerDialect() const { return AssemblerDialect; }
434 bool doesAllowAtInName() const { return AllowAtInName; }
435 bool doesSupportDataRegionDirectives() const {
436 return UseDataRegionDirectives;
438 const char *getZeroDirective() const { return ZeroDirective; }
439 const char *getAsciiDirective() const { return AsciiDirective; }
440 const char *getAscizDirective() const { return AscizDirective; }
441 bool getAlignmentIsInBytes() const { return AlignmentIsInBytes; }
442 unsigned getTextAlignFillValue() const { return TextAlignFillValue; }
443 const char *getGlobalDirective() const { return GlobalDirective; }
444 bool hasSetDirective() const { return HasSetDirective; }
445 bool hasAggressiveSymbolFolding() const { return HasAggressiveSymbolFolding; }
446 bool getCOMMDirectiveAlignmentIsInBytes() const {
447 return COMMDirectiveAlignmentIsInBytes;
449 LCOMM::LCOMMType getLCOMMDirectiveAlignmentType() const {
450 return LCOMMDirectiveAlignmentType;
452 bool hasDotTypeDotSizeDirective() const { return HasDotTypeDotSizeDirective; }
453 bool hasSingleParameterDotFile() const { return HasSingleParameterDotFile; }
454 bool hasIdentDirective() const { return HasIdentDirective; }
455 bool hasNoDeadStrip() const { return HasNoDeadStrip; }
456 const char *getWeakRefDirective() const { return WeakRefDirective; }
457 bool hasWeakDefDirective() const { return HasWeakDefDirective; }
458 bool hasWeakDefCanBeHiddenDirective() const {
459 return HasWeakDefCanBeHiddenDirective;
461 bool hasLinkOnceDirective() const { return HasLinkOnceDirective; }
463 MCSymbolAttr getHiddenVisibilityAttr() const { return HiddenVisibilityAttr; }
464 MCSymbolAttr getHiddenDeclarationVisibilityAttr() const {
465 return HiddenDeclarationVisibilityAttr;
467 MCSymbolAttr getProtectedVisibilityAttr() const {
468 return ProtectedVisibilityAttr;
470 bool hasLEB128() const { return HasLEB128; }
471 bool doesSupportDebugInformation() const { return SupportsDebugInformation; }
472 bool doesSupportExceptionHandling() const {
473 return ExceptionsType != ExceptionHandling::None;
475 ExceptionHandling::ExceptionsType getExceptionHandlingType() const {
476 return ExceptionsType;
478 WinEH::EncodingType getWinEHEncodingType() const {
479 return WinEHEncodingType;
481 bool isExceptionHandlingDwarf() const {
482 return (ExceptionsType == ExceptionHandling::DwarfCFI ||
483 ExceptionsType == ExceptionHandling::ARM ||
484 ExceptionsType == ExceptionHandling::Win64);
486 bool doesDwarfUseRelocationsAcrossSections() const {
487 return DwarfUsesRelocationsAcrossSections;
489 bool doDwarfFDESymbolsUseAbsDiff() const { return DwarfFDESymbolsUseAbsDiff; }
490 bool useDwarfRegNumForCFI() const { return DwarfRegNumForCFI; }
491 bool useParensForSymbolVariant() const { return UseParensForSymbolVariant; }
493 void addInitialFrameState(const MCCFIInstruction &Inst) {
494 InitialFrameState.push_back(Inst);
497 const std::vector<MCCFIInstruction> &getInitialFrameState() const {
498 return InitialFrameState;
501 /// Return true if assembly (inline or otherwise) should be parsed.
502 bool useIntegratedAssembler() const { return UseIntegratedAssembler; }
504 /// Set whether assembly (inline or otherwise) should be parsed.
505 virtual void setUseIntegratedAssembler(bool Value) {
506 UseIntegratedAssembler = Value;
509 bool compressDebugSections() const { return CompressDebugSections; }
511 void setCompressDebugSections(bool CompressDebugSections) {
512 this->CompressDebugSections = CompressDebugSections;