1 //===-- llvm/MC/MCAsmInfo.h - Asm info --------------------------*- C++ -*-===// 2 // 3 // The LLVM Compiler Infrastructure 4 // 5 // This file is distributed under the University of Illinois Open Source 6 // License. See LICENSE.TXT for details. 7 // 8 //===----------------------------------------------------------------------===// 9 // 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. 13 // 14 //===----------------------------------------------------------------------===// 15 16 #ifndef LLVM_TARGET_ASM_INFO_H 17 #define LLVM_TARGET_ASM_INFO_H 18 19 #include "llvm/MC/MachineLocation.h" 20 #include "llvm/MC/MCDirectives.h" 21 #include <cassert> 22 #include <vector> 23 24 namespace llvm { 25 class MCExpr; 26 class MCSection; 27 class MCStreamer; 28 class MCSymbol; 29 class MCContext; 30 31 namespace ExceptionHandling { 32 enum ExceptionsType { None, DwarfCFI, SjLj, ARM, Win64 }; 33 } 34 35 namespace LCOMM { 36 enum LCOMMType { None, NoAlignment, ByteAlignment }; 37 } 38 39 /// MCAsmInfo - This class is intended to be used as a base class for asm 40 /// properties and features specific to the target. 41 class MCAsmInfo { 42 protected: 43 //===------------------------------------------------------------------===// 44 // Properties to be set by the target writer, used to configure asm printer. 45 // 46 47 /// PointerSize - Pointer size in bytes. 48 /// Default is 4. 49 unsigned PointerSize; 50 51 /// IsLittleEndian - True if target is little endian. 52 /// Default is true. 53 bool IsLittleEndian; 54 55 /// StackGrowsUp - True if target stack grow up. 56 /// Default is false. 57 bool StackGrowsUp; 58 59 /// HasSubsectionsViaSymbols - True if this target has the MachO 60 /// .subsections_via_symbols directive. 61 bool HasSubsectionsViaSymbols; // Default is false. 62 63 /// HasMachoZeroFillDirective - True if this is a MachO target that supports 64 /// the macho-specific .zerofill directive for emitting BSS Symbols. 65 bool HasMachoZeroFillDirective; // Default is false. 66 67 /// HasMachoTBSSDirective - True if this is a MachO target that supports 68 /// the macho-specific .tbss directive for emitting thread local BSS Symbols 69 bool HasMachoTBSSDirective; // Default is false. 70 71 /// HasStaticCtorDtorReferenceInStaticMode - True if the compiler should 72 /// emit a ".reference .constructors_used" or ".reference .destructors_used" 73 /// directive after the a static ctor/dtor list. This directive is only 74 /// emitted in Static relocation model. 75 bool HasStaticCtorDtorReferenceInStaticMode; // Default is false. 76 77 /// LinkerRequiresNonEmptyDwarfLines - True if the linker has a bug and 78 /// requires that the debug_line section be of a minimum size. In practice 79 /// such a linker requires a non empty line sequence if a file is present. 80 bool LinkerRequiresNonEmptyDwarfLines; // Default to false. 81 82 /// MaxInstLength - This is the maximum possible length of an instruction, 83 /// which is needed to compute the size of an inline asm. 84 unsigned MaxInstLength; // Defaults to 4. 85 86 /// PCSymbol - The symbol used to represent the current PC. Used in PC 87 /// relative expressions. 88 const char *PCSymbol; // Defaults to "$". 89 90 /// SeparatorString - This string, if specified, is used to separate 91 /// instructions from each other when on the same line. 92 const char *SeparatorString; // Defaults to ';' 93 94 /// CommentColumn - This indicates the comment num (zero-based) at 95 /// which asm comments should be printed. 96 unsigned CommentColumn; // Defaults to 40 97 98 /// CommentString - This indicates the comment character used by the 99 /// assembler. 100 const char *CommentString; // Defaults to "#" 101 102 /// LabelSuffix - This is appended to emitted labels. 103 const char *LabelSuffix; // Defaults to ":" 104 105 /// GlobalPrefix - If this is set to a non-empty string, it is prepended 106 /// onto all global symbols. This is often used for "_" or ".". 107 const char *GlobalPrefix; // Defaults to "" 108 109 /// PrivateGlobalPrefix - This prefix is used for globals like constant 110 /// pool entries that are completely private to the .s file and should not 111 /// have names in the .o file. This is often "." or "L". 112 const char *PrivateGlobalPrefix; // Defaults to "." 113 114 /// LinkerPrivateGlobalPrefix - This prefix is used for symbols that should 115 /// be passed through the assembler but be removed by the linker. This 116 /// is "l" on Darwin, currently used for some ObjC metadata. 117 const char *LinkerPrivateGlobalPrefix; // Defaults to "" 118 119 /// InlineAsmStart/End - If these are nonempty, they contain a directive to 120 /// emit before and after an inline assembly statement. 121 const char *InlineAsmStart; // Defaults to "#APP\n" 122 const char *InlineAsmEnd; // Defaults to "#NO_APP\n" 123 124 /// Code16Directive, Code32Directive, Code64Directive - These are assembly 125 /// directives that tells the assembler to interpret the following 126 /// instructions differently. 127 const char *Code16Directive; // Defaults to ".code16" 128 const char *Code32Directive; // Defaults to ".code32" 129 const char *Code64Directive; // Defaults to ".code64" 130 131 /// AssemblerDialect - Which dialect of an assembler variant to use. 132 unsigned AssemblerDialect; // Defaults to 0 133 134 /// AllowQuotesInName - This is true if the assembler allows for complex 135 /// symbol names to be surrounded in quotes. This defaults to false. 136 bool AllowQuotesInName; 137 138 /// AllowNameToStartWithDigit - This is true if the assembler allows symbol 139 /// names to start with a digit (e.g., "0x0021"). This defaults to false. 140 bool AllowNameToStartWithDigit; 141 142 /// AllowPeriodsInName - This is true if the assembler allows periods in 143 /// symbol names. This defaults to true. 144 bool AllowPeriodsInName; 145 146 /// AllowUTF8 - This is true if the assembler accepts UTF-8 input. 147 // FIXME: Make this a more general encoding setting? 148 bool AllowUTF8; 149 150 //===--- Data Emission Directives -------------------------------------===// 151 152 /// ZeroDirective - this should be set to the directive used to get some 153 /// number of zero bytes emitted to the current section. Common cases are 154 /// "\t.zero\t" and "\t.space\t". If this is set to null, the 155 /// Data*bitsDirective's will be used to emit zero bytes. 156 const char *ZeroDirective; // Defaults to "\t.zero\t" 157 158 /// AsciiDirective - This directive allows emission of an ascii string with 159 /// the standard C escape characters embedded into it. 160 const char *AsciiDirective; // Defaults to "\t.ascii\t" 161 162 /// AscizDirective - If not null, this allows for special handling of 163 /// zero terminated strings on this target. This is commonly supported as 164 /// ".asciz". If a target doesn't support this, it can be set to null. 165 const char *AscizDirective; // Defaults to "\t.asciz\t" 166 167 /// DataDirectives - These directives are used to output some unit of 168 /// integer data to the current section. If a data directive is set to 169 /// null, smaller data directives will be used to emit the large sizes. 170 const char *Data8bitsDirective; // Defaults to "\t.byte\t" 171 const char *Data16bitsDirective; // Defaults to "\t.short\t" 172 const char *Data32bitsDirective; // Defaults to "\t.long\t" 173 const char *Data64bitsDirective; // Defaults to "\t.quad\t" 174 175 /// [Data|Code]Begin - These magic labels are used to marked a region as 176 /// data or code, and are used to provide additional information for 177 /// correct disassembly on targets that like to mix data and code within 178 /// a segment. These labels will be implicitly suffixed by the streamer 179 /// to give them unique names. 180 const char *DataBegin; // Defaults to "$d." 181 const char *CodeBegin; // Defaults to "$a." 182 const char *JT8Begin; // Defaults to "$a." 183 const char *JT16Begin; // Defaults to "$a." 184 const char *JT32Begin; // Defaults to "$a." 185 bool SupportsDataRegions; 186 187 /// GPRel64Directive - if non-null, a directive that is used to emit a word 188 /// which should be relocated as a 64-bit GP-relative offset, e.g. .gpdword 189 /// on Mips. 190 const char *GPRel64Directive; // Defaults to NULL. 191 192 /// GPRel32Directive - if non-null, a directive that is used to emit a word 193 /// which should be relocated as a 32-bit GP-relative offset, e.g. .gpword 194 /// on Mips or .gprel32 on Alpha. 195 const char *GPRel32Directive; // Defaults to NULL. 196 197 /// getDataASDirective - Return the directive that should be used to emit 198 /// data of the specified size to the specified numeric address space. 199 virtual const char *getDataASDirective(unsigned Size, unsigned AS) const { 200 assert(AS != 0 && "Don't know the directives for default addr space"); 201 return 0; 202 } 203 204 /// SunStyleELFSectionSwitchSyntax - This is true if this target uses "Sun 205 /// Style" syntax for section switching ("#alloc,#write" etc) instead of the 206 /// normal ELF syntax (,"a,w") in .section directives. 207 bool SunStyleELFSectionSwitchSyntax; // Defaults to false. 208 209 /// UsesELFSectionDirectiveForBSS - This is true if this target uses ELF 210 /// '.section' directive before the '.bss' one. It's used for PPC/Linux 211 /// which doesn't support the '.bss' directive only. 212 bool UsesELFSectionDirectiveForBSS; // Defaults to false. 213 214 /// HasMicrosoftFastStdCallMangling - True if this target uses microsoft 215 /// style mangling for functions with X86_StdCall/X86_FastCall calling 216 /// convention. 217 bool HasMicrosoftFastStdCallMangling; // Defaults to false. 218 219 //===--- Alignment Information ----------------------------------------===// 220 221 /// AlignDirective - The directive used to emit round up to an alignment 222 /// boundary. 223 /// 224 const char *AlignDirective; // Defaults to "\t.align\t" 225 226 /// AlignmentIsInBytes - If this is true (the default) then the asmprinter 227 /// emits ".align N" directives, where N is the number of bytes to align to. 228 /// Otherwise, it emits ".align log2(N)", e.g. 3 to align to an 8 byte 229 /// boundary. 230 bool AlignmentIsInBytes; // Defaults to true 231 232 /// TextAlignFillValue - If non-zero, this is used to fill the executable 233 /// space created as the result of a alignment directive. 234 unsigned TextAlignFillValue; // Defaults to 0 235 236 //===--- Global Variable Emission Directives --------------------------===// 237 238 /// GlobalDirective - This is the directive used to declare a global entity. 239 /// 240 const char *GlobalDirective; // Defaults to NULL. 241 242 /// ExternDirective - This is the directive used to declare external 243 /// globals. 244 /// 245 const char *ExternDirective; // Defaults to NULL. 246 247 /// HasSetDirective - True if the assembler supports the .set directive. 248 bool HasSetDirective; // Defaults to true. 249 250 /// HasAggressiveSymbolFolding - False if the assembler requires that we use 251 /// Lc = a - b 252 /// .long Lc 253 /// instead of 254 /// .long a - b 255 bool HasAggressiveSymbolFolding; // Defaults to true. 256 257 /// LCOMMDirectiveType - Describes if the target supports the .lcomm 258 /// directive and whether it has an alignment parameter. 259 LCOMM::LCOMMType LCOMMDirectiveType; // Defaults to LCOMM::None. 260 261 /// COMMDirectiveAlignmentIsInBytes - True is COMMDirective's optional 262 /// alignment is to be specified in bytes instead of log2(n). 263 bool COMMDirectiveAlignmentIsInBytes; // Defaults to true; 264 265 /// HasDotTypeDotSizeDirective - True if the target has .type and .size 266 /// directives, this is true for most ELF targets. 267 bool HasDotTypeDotSizeDirective; // Defaults to true. 268 269 /// HasSingleParameterDotFile - True if the target has a single parameter 270 /// .file directive, this is true for ELF targets. 271 bool HasSingleParameterDotFile; // Defaults to true. 272 273 /// HasNoDeadStrip - True if this target supports the MachO .no_dead_strip 274 /// directive. 275 bool HasNoDeadStrip; // Defaults to false. 276 277 /// HasSymbolResolver - True if this target supports the MachO 278 /// .symbol_resolver directive. 279 bool HasSymbolResolver; // Defaults to false. 280 281 /// WeakRefDirective - This directive, if non-null, is used to declare a 282 /// global as being a weak undefined symbol. 283 const char *WeakRefDirective; // Defaults to NULL. 284 285 /// WeakDefDirective - This directive, if non-null, is used to declare a 286 /// global as being a weak defined symbol. 287 const char *WeakDefDirective; // Defaults to NULL. 288 289 /// LinkOnceDirective - This directive, if non-null is used to declare a 290 /// global as being a weak defined symbol. This is used on cygwin/mingw. 291 const char *LinkOnceDirective; // Defaults to NULL. 292 293 /// HiddenVisibilityAttr - This attribute, if not MCSA_Invalid, is used to 294 /// declare a symbol as having hidden visibility. 295 MCSymbolAttr HiddenVisibilityAttr; // Defaults to MCSA_Hidden. 296 297 /// HiddenDeclarationVisibilityAttr - This attribute, if not MCSA_Invalid, 298 /// is used to declare an undefined symbol as having hidden visibility. 299 MCSymbolAttr HiddenDeclarationVisibilityAttr; // Defaults to MCSA_Hidden. 300 301 302 /// ProtectedVisibilityAttr - This attribute, if not MCSA_Invalid, is used 303 /// to declare a symbol as having protected visibility. 304 MCSymbolAttr ProtectedVisibilityAttr; // Defaults to MCSA_Protected 305 306 //===--- Dwarf Emission Directives -----------------------------------===// 307 308 /// HasLEB128 - True if target asm supports leb128 directives. 309 bool HasLEB128; // Defaults to false. 310 311 /// SupportsDebugInformation - True if target supports emission of debugging 312 /// information. 313 bool SupportsDebugInformation; // Defaults to false. 314 315 /// SupportsExceptionHandling - True if target supports exception handling. 316 ExceptionHandling::ExceptionsType ExceptionsType; // Defaults to None 317 318 /// DwarfUsesInlineInfoSection - True if DwarfDebugInlineSection is used to 319 /// encode inline subroutine information. 320 bool DwarfUsesInlineInfoSection; // Defaults to false. 321 322 /// DwarfSectionOffsetDirective - Special section offset directive. 323 const char* DwarfSectionOffsetDirective; // Defaults to NULL 324 325 /// DwarfRequiresRelocationForSectionOffset - True if we need to produce a 326 /// relocation when we want a section offset in dwarf. 327 bool DwarfRequiresRelocationForSectionOffset; // Defaults to true; 328 329 /// DwarfUsesLabelOffsetDifference - True if Dwarf2 output can 330 /// use EmitLabelOffsetDifference. 331 bool DwarfUsesLabelOffsetForRanges; 332 333 /// DwarfUsesRelocationsForStringPool - True if this Dwarf output must use 334 /// relocations to refer to entries in the string pool. 335 bool DwarfUsesRelocationsForStringPool; 336 337 /// DwarfRegNumForCFI - True if dwarf register numbers are printed 338 /// instead of symbolic register names in .cfi_* directives. 339 bool DwarfRegNumForCFI; // Defaults to false; 340 341 //===--- CBE Asm Translation Table -----------------------------------===// 342 343 const char *const *AsmTransCBE; // Defaults to empty 344 345 //===--- Prologue State ----------------------------------------------===// 346 347 std::vector<MachineMove> InitialFrameState; 348 349 public: 350 explicit MCAsmInfo(); 351 virtual ~MCAsmInfo(); 352 353 // FIXME: move these methods to DwarfPrinter when the JIT stops using them. 354 static unsigned getSLEB128Size(int Value); 355 static unsigned getULEB128Size(unsigned Value); 356 357 /// getPointerSize - Get the pointer size in bytes. 358 unsigned getPointerSize() const { 359 return PointerSize; 360 } 361 362 /// islittleendian - True if the target is little endian. 363 bool isLittleEndian() const { 364 return IsLittleEndian; 365 } 366 367 /// isStackGrowthDirectionUp - True if target stack grow up. 368 bool isStackGrowthDirectionUp() const { 369 return StackGrowsUp; 370 } 371 372 bool hasSubsectionsViaSymbols() const { return HasSubsectionsViaSymbols; } 373 374 // Data directive accessors. 375 // 376 const char *getData8bitsDirective(unsigned AS = 0) const { 377 return AS == 0 ? Data8bitsDirective : getDataASDirective(8, AS); 378 } 379 const char *getData16bitsDirective(unsigned AS = 0) const { 380 return AS == 0 ? Data16bitsDirective : getDataASDirective(16, AS); 381 } 382 const char *getData32bitsDirective(unsigned AS = 0) const { 383 return AS == 0 ? Data32bitsDirective : getDataASDirective(32, AS); 384 } 385 const char *getData64bitsDirective(unsigned AS = 0) const { 386 return AS == 0 ? Data64bitsDirective : getDataASDirective(64, AS); 387 } 388 const char *getGPRel64Directive() const { return GPRel64Directive; } 389 const char *getGPRel32Directive() const { return GPRel32Directive; } 390 391 /// [Code|Data]Begin label name accessors. 392 const char *getCodeBeginLabelName() const { return CodeBegin; } 393 const char *getDataBeginLabelName() const { return DataBegin; } 394 const char *getJumpTable8BeginLabelName() const { return JT8Begin; } 395 const char *getJumpTable16BeginLabelName() const { return JT16Begin; } 396 const char *getJumpTable32BeginLabelName() const { return JT32Begin; } 397 bool getSupportsDataRegions() const { return SupportsDataRegions; } 398 399 /// getNonexecutableStackSection - Targets can implement this method to 400 /// specify a section to switch to if the translation unit doesn't have any 401 /// trampolines that require an executable stack. 402 virtual const MCSection *getNonexecutableStackSection(MCContext &Ctx) const{ 403 return 0; 404 } 405 406 virtual const MCExpr * 407 getExprForPersonalitySymbol(const MCSymbol *Sym, 408 unsigned Encoding, 409 MCStreamer &Streamer) const; 410 411 const MCExpr * 412 getExprForFDESymbol(const MCSymbol *Sym, 413 unsigned Encoding, 414 MCStreamer &Streamer) const; 415 416 bool usesSunStyleELFSectionSwitchSyntax() const { 417 return SunStyleELFSectionSwitchSyntax; 418 } 419 420 bool usesELFSectionDirectiveForBSS() const { 421 return UsesELFSectionDirectiveForBSS; 422 } 423 424 bool hasMicrosoftFastStdCallMangling() const { 425 return HasMicrosoftFastStdCallMangling; 426 } 427 428 // Accessors. 429 // 430 bool hasMachoZeroFillDirective() const { return HasMachoZeroFillDirective; } 431 bool hasMachoTBSSDirective() const { return HasMachoTBSSDirective; } 432 bool hasStaticCtorDtorReferenceInStaticMode() const { 433 return HasStaticCtorDtorReferenceInStaticMode; 434 } 435 bool getLinkerRequiresNonEmptyDwarfLines() const { 436 return LinkerRequiresNonEmptyDwarfLines; 437 } 438 unsigned getMaxInstLength() const { 439 return MaxInstLength; 440 } 441 const char *getPCSymbol() const { 442 return PCSymbol; 443 } 444 const char *getSeparatorString() const { 445 return SeparatorString; 446 } 447 unsigned getCommentColumn() const { 448 return CommentColumn; 449 } 450 const char *getCommentString() const { 451 return CommentString; 452 } 453 const char *getLabelSuffix() const { 454 return LabelSuffix; 455 } 456 const char *getGlobalPrefix() const { 457 return GlobalPrefix; 458 } 459 const char *getPrivateGlobalPrefix() const { 460 return PrivateGlobalPrefix; 461 } 462 const char *getLinkerPrivateGlobalPrefix() const { 463 return LinkerPrivateGlobalPrefix; 464 } 465 const char *getInlineAsmStart() const { 466 return InlineAsmStart; 467 } 468 const char *getInlineAsmEnd() const { 469 return InlineAsmEnd; 470 } 471 const char *getCode16Directive() const { 472 return Code16Directive; 473 } 474 const char *getCode32Directive() const { 475 return Code32Directive; 476 } 477 const char *getCode64Directive() const { 478 return Code64Directive; 479 } 480 unsigned getAssemblerDialect() const { 481 return AssemblerDialect; 482 } 483 bool doesAllowQuotesInName() const { 484 return AllowQuotesInName; 485 } 486 bool doesAllowNameToStartWithDigit() const { 487 return AllowNameToStartWithDigit; 488 } 489 bool doesAllowPeriodsInName() const { 490 return AllowPeriodsInName; 491 } 492 bool doesAllowUTF8() const { 493 return AllowUTF8; 494 } 495 const char *getZeroDirective() const { 496 return ZeroDirective; 497 } 498 const char *getAsciiDirective() const { 499 return AsciiDirective; 500 } 501 const char *getAscizDirective() const { 502 return AscizDirective; 503 } 504 const char *getAlignDirective() const { 505 return AlignDirective; 506 } 507 bool getAlignmentIsInBytes() const { 508 return AlignmentIsInBytes; 509 } 510 unsigned getTextAlignFillValue() const { 511 return TextAlignFillValue; 512 } 513 const char *getGlobalDirective() const { 514 return GlobalDirective; 515 } 516 const char *getExternDirective() const { 517 return ExternDirective; 518 } 519 bool hasSetDirective() const { return HasSetDirective; } 520 bool hasAggressiveSymbolFolding() const { 521 return HasAggressiveSymbolFolding; 522 } 523 LCOMM::LCOMMType getLCOMMDirectiveType() const { 524 return LCOMMDirectiveType; 525 } 526 bool hasDotTypeDotSizeDirective() const {return HasDotTypeDotSizeDirective;} 527 bool getCOMMDirectiveAlignmentIsInBytes() const { 528 return COMMDirectiveAlignmentIsInBytes; 529 } 530 bool hasSingleParameterDotFile() const { return HasSingleParameterDotFile; } 531 bool hasNoDeadStrip() const { return HasNoDeadStrip; } 532 bool hasSymbolResolver() const { return HasSymbolResolver; } 533 const char *getWeakRefDirective() const { return WeakRefDirective; } 534 const char *getWeakDefDirective() const { return WeakDefDirective; } 535 const char *getLinkOnceDirective() const { return LinkOnceDirective; } 536 537 MCSymbolAttr getHiddenVisibilityAttr() const { return HiddenVisibilityAttr;} 538 MCSymbolAttr getHiddenDeclarationVisibilityAttr() const { 539 return HiddenDeclarationVisibilityAttr; 540 } 541 MCSymbolAttr getProtectedVisibilityAttr() const { 542 return ProtectedVisibilityAttr; 543 } 544 bool hasLEB128() const { 545 return HasLEB128; 546 } 547 bool doesSupportDebugInformation() const { 548 return SupportsDebugInformation; 549 } 550 bool doesSupportExceptionHandling() const { 551 return ExceptionsType != ExceptionHandling::None; 552 } 553 ExceptionHandling::ExceptionsType getExceptionHandlingType() const { 554 return ExceptionsType; 555 } 556 bool isExceptionHandlingDwarf() const { 557 return 558 (ExceptionsType == ExceptionHandling::DwarfCFI || 559 ExceptionsType == ExceptionHandling::ARM || 560 ExceptionsType == ExceptionHandling::Win64); 561 } 562 bool doesDwarfUseInlineInfoSection() const { 563 return DwarfUsesInlineInfoSection; 564 } 565 const char *getDwarfSectionOffsetDirective() const { 566 return DwarfSectionOffsetDirective; 567 } 568 bool doesDwarfRequireRelocationForSectionOffset() const { 569 return DwarfRequiresRelocationForSectionOffset; 570 } 571 bool doesDwarfUseLabelOffsetForRanges() const { 572 return DwarfUsesLabelOffsetForRanges; 573 } 574 bool doesDwarfUseRelocationsForStringPool() const { 575 return DwarfUsesRelocationsForStringPool; 576 } 577 bool useDwarfRegNumForCFI() const { 578 return DwarfRegNumForCFI; 579 } 580 const char *const *getAsmCBE() const { 581 return AsmTransCBE; 582 } 583 584 void addInitialFrameState(MCSymbol *label, const MachineLocation &D, 585 const MachineLocation &S) { 586 InitialFrameState.push_back(MachineMove(label, D, S)); 587 } 588 const std::vector<MachineMove> &getInitialFrameState() const { 589 return InitialFrameState; 590 } 591 }; 592 } 593 594 #endif 595