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_MC_MCASMINFO_H 17 #define LLVM_MC_MCASMINFO_H 18 19 #include "llvm/MC/MCDirectives.h" 20 #include "llvm/MC/MCDwarf.h" 21 #include "llvm/MC/MachineLocation.h" 22 #include <cassert> 23 #include <vector> 24 25 namespace llvm { 26 class MCExpr; 27 class MCSection; 28 class MCStreamer; 29 class MCSymbol; 30 class MCContext; 31 32 namespace ExceptionHandling { 33 enum ExceptionsType { None, DwarfCFI, SjLj, ARM, Win64 }; 34 } 35 36 namespace LCOMM { 37 enum LCOMMType { NoAlignment, ByteAlignment, Log2Alignment }; 38 } 39 40 /// MCAsmInfo - This class is intended to be used as a base class for asm 41 /// properties and features specific to the target. 42 class MCAsmInfo { 43 protected: 44 //===------------------------------------------------------------------===// 45 // Properties to be set by the target writer, used to configure asm printer. 46 // 47 48 /// PointerSize - Pointer size in bytes. 49 /// Default is 4. 50 unsigned PointerSize; 51 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; 56 57 /// IsLittleEndian - True if target is little endian. 58 /// Default is true. 59 bool IsLittleEndian; 60 61 /// StackGrowsUp - True if target stack grow up. 62 /// Default is false. 63 bool StackGrowsUp; 64 65 /// HasSubsectionsViaSymbols - True if this target has the MachO 66 /// .subsections_via_symbols directive. 67 bool HasSubsectionsViaSymbols; // Default is false. 68 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. 72 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. 76 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. 82 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. 87 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. 91 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. 95 96 /// PCSymbol - The symbol used to represent the current PC. Used in PC 97 /// relative expressions. 98 const char *PCSymbol; // Defaults to "$". 99 100 /// 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 ';' 103 104 /// CommentColumn - This indicates the comment num (zero-based) at 105 /// which asm comments should be printed. 106 unsigned CommentColumn; // Defaults to 40 107 108 /// CommentString - This indicates the comment character used by the 109 /// assembler. 110 const char *CommentString; // Defaults to "#" 111 112 /// LabelSuffix - This is appended to emitted labels. 113 const char *LabelSuffix; // Defaults to ":" 114 115 /// LabelSuffix - This is appended to emitted labels. 116 const char *DebugLabelSuffix; // Defaults to ":" 117 118 /// GlobalPrefix - If this is set to a non-empty string, it is prepended 119 /// onto all global symbols. This is often used for "_" or ".". 120 const char *GlobalPrefix; // Defaults to "" 121 122 /// PrivateGlobalPrefix - This prefix is used for globals like constant 123 /// pool entries that are completely private to the .s file and should not 124 /// have names in the .o file. This is often "." or "L". 125 const char *PrivateGlobalPrefix; // Defaults to "." 126 127 /// LinkerPrivateGlobalPrefix - This prefix is used for symbols that should 128 /// be passed through the assembler but be removed by the linker. This 129 /// is "l" on Darwin, currently used for some ObjC metadata. 130 const char *LinkerPrivateGlobalPrefix; // Defaults to "" 131 132 /// InlineAsmStart/End - If these are nonempty, they contain a directive to 133 /// emit before and after an inline assembly statement. 134 const char *InlineAsmStart; // Defaults to "#APP\n" 135 const char *InlineAsmEnd; // Defaults to "#NO_APP\n" 136 137 /// Code16Directive, Code32Directive, Code64Directive - These are assembly 138 /// directives that tells the assembler to interpret the following 139 /// instructions differently. 140 const char *Code16Directive; // Defaults to ".code16" 141 const char *Code32Directive; // Defaults to ".code32" 142 const char *Code64Directive; // Defaults to ".code64" 143 144 /// AssemblerDialect - Which dialect of an assembler variant to use. 145 unsigned AssemblerDialect; // Defaults to 0 146 147 /// AllowQuotesInName - This is true if the assembler allows for complex 148 /// symbol names to be surrounded in quotes. This defaults to false. 149 bool AllowQuotesInName; 150 151 /// AllowNameToStartWithDigit - This is true if the assembler allows symbol 152 /// names to start with a digit (e.g., "0x0021"). This defaults to false. 153 bool AllowNameToStartWithDigit; 154 155 /// AllowPeriodsInName - This is true if the assembler allows periods in 156 /// symbol names. This defaults to true. 157 bool AllowPeriodsInName; 158 159 /// AllowUTF8 - This is true if the assembler accepts UTF-8 input. 160 // FIXME: Make this a more general encoding setting? 161 bool AllowUTF8; 162 163 /// UseDataRegionDirectives - This is true if data region markers should 164 /// be printed as ".data_region/.end_data_region" directives. If false, 165 /// use "$d/$a" labels instead. 166 bool UseDataRegionDirectives; 167 168 //===--- Data Emission Directives -------------------------------------===// 169 170 /// ZeroDirective - this should be set to the directive used to get some 171 /// number of zero bytes emitted to the current section. Common cases are 172 /// "\t.zero\t" and "\t.space\t". If this is set to null, the 173 /// Data*bitsDirective's will be used to emit zero bytes. 174 const char *ZeroDirective; // Defaults to "\t.zero\t" 175 176 /// AsciiDirective - This directive allows emission of an ascii string with 177 /// the standard C escape characters embedded into it. 178 const char *AsciiDirective; // Defaults to "\t.ascii\t" 179 180 /// AscizDirective - If not null, this allows for special handling of 181 /// zero terminated strings on this target. This is commonly supported as 182 /// ".asciz". If a target doesn't support this, it can be set to null. 183 const char *AscizDirective; // Defaults to "\t.asciz\t" 184 185 /// DataDirectives - These directives are used to output some unit of 186 /// integer data to the current section. If a data directive is set to 187 /// null, smaller data directives will be used to emit the large sizes. 188 const char *Data8bitsDirective; // Defaults to "\t.byte\t" 189 const char *Data16bitsDirective; // Defaults to "\t.short\t" 190 const char *Data32bitsDirective; // Defaults to "\t.long\t" 191 const char *Data64bitsDirective; // Defaults to "\t.quad\t" 192 193 /// GPRel64Directive - if non-null, a directive that is used to emit a word 194 /// which should be relocated as a 64-bit GP-relative offset, e.g. .gpdword 195 /// on Mips. 196 const char *GPRel64Directive; // Defaults to NULL. 197 198 /// GPRel32Directive - if non-null, a directive that is used to emit a word 199 /// which should be relocated as a 32-bit GP-relative offset, e.g. .gpword 200 /// on Mips or .gprel32 on Alpha. 201 const char *GPRel32Directive; // Defaults to NULL. 202 203 /// SunStyleELFSectionSwitchSyntax - This is true if this target uses "Sun 204 /// Style" syntax for section switching ("#alloc,#write" etc) instead of the 205 /// normal ELF syntax (,"a,w") in .section directives. 206 bool SunStyleELFSectionSwitchSyntax; // Defaults to false. 207 208 /// UsesELFSectionDirectiveForBSS - This is true if this target uses ELF 209 /// '.section' directive before the '.bss' one. It's used for PPC/Linux 210 /// which doesn't support the '.bss' directive only. 211 bool UsesELFSectionDirectiveForBSS; // Defaults to false. 212 213 /// HasMicrosoftFastStdCallMangling - True if this target uses microsoft 214 /// style mangling for functions with X86_StdCall/X86_FastCall calling 215 /// convention. 216 bool HasMicrosoftFastStdCallMangling; // Defaults to false. 217 218 bool NeedsDwarfSectionOffsetDirective; 219 220 //===--- Alignment Information ----------------------------------------===// 221 222 /// AlignDirective - The directive used to emit round up to an alignment 223 /// boundary. 224 /// 225 const char *AlignDirective; // Defaults to "\t.align\t" 226 227 /// AlignmentIsInBytes - If this is true (the default) then the asmprinter 228 /// emits ".align N" directives, where N is the number of bytes to align to. 229 /// Otherwise, it emits ".align log2(N)", e.g. 3 to align to an 8 byte 230 /// boundary. 231 bool AlignmentIsInBytes; // Defaults to true 232 233 /// TextAlignFillValue - If non-zero, this is used to fill the executable 234 /// space created as the result of a alignment directive. 235 unsigned TextAlignFillValue; // Defaults to 0 236 237 //===--- Global Variable Emission Directives --------------------------===// 238 239 /// GlobalDirective - This is the directive used to declare a global entity. 240 /// 241 const char *GlobalDirective; // Defaults to NULL. 242 243 /// ExternDirective - This is the directive used to declare external 244 /// globals. 245 /// 246 const char *ExternDirective; // Defaults to NULL. 247 248 /// HasSetDirective - True if the assembler supports the .set directive. 249 bool HasSetDirective; // Defaults to true. 250 251 /// HasAggressiveSymbolFolding - False if the assembler requires that we use 252 /// Lc = a - b 253 /// .long Lc 254 /// instead of 255 /// .long a - b 256 bool HasAggressiveSymbolFolding; // Defaults to true. 257 258 /// COMMDirectiveAlignmentIsInBytes - True is .comm's and .lcomms optional 259 /// alignment is to be specified in bytes instead of log2(n). 260 bool COMMDirectiveAlignmentIsInBytes; // Defaults to true; 261 262 /// LCOMMDirectiveAlignment - Describes if the .lcomm directive for the 263 /// target supports an alignment argument and how it is interpreted. 264 LCOMM::LCOMMType LCOMMDirectiveAlignmentType; // Defaults to NoAlignment. 265 266 /// HasDotTypeDotSizeDirective - True if the target has .type and .size 267 /// directives, this is true for most ELF targets. 268 bool HasDotTypeDotSizeDirective; // Defaults to true. 269 270 /// HasSingleParameterDotFile - True if the target has a single parameter 271 /// .file directive, this is true for ELF targets. 272 bool HasSingleParameterDotFile; // Defaults to true. 273 274 /// HasNoDeadStrip - True if this target supports the MachO .no_dead_strip 275 /// directive. 276 bool HasNoDeadStrip; // Defaults to false. 277 278 /// HasSymbolResolver - True if this target supports the MachO 279 /// .symbol_resolver directive. 280 bool HasSymbolResolver; // Defaults to false. 281 282 /// WeakRefDirective - This directive, if non-null, is used to declare a 283 /// global as being a weak undefined symbol. 284 const char *WeakRefDirective; // Defaults to NULL. 285 286 /// WeakDefDirective - This directive, if non-null, is used to declare a 287 /// global as being a weak defined symbol. 288 const char *WeakDefDirective; // Defaults to NULL. 289 290 /// LinkOnceDirective - This directive, if non-null is used to declare a 291 /// global as being a weak defined symbol. This is used on cygwin/mingw. 292 const char *LinkOnceDirective; // Defaults to NULL. 293 294 /// HiddenVisibilityAttr - This attribute, if not MCSA_Invalid, is used to 295 /// declare a symbol as having hidden visibility. 296 MCSymbolAttr HiddenVisibilityAttr; // Defaults to MCSA_Hidden. 297 298 /// HiddenDeclarationVisibilityAttr - This attribute, if not MCSA_Invalid, 299 /// is used to declare an undefined symbol as having hidden visibility. 300 MCSymbolAttr HiddenDeclarationVisibilityAttr; // Defaults to MCSA_Hidden. 301 302 303 /// ProtectedVisibilityAttr - This attribute, if not MCSA_Invalid, is used 304 /// to declare a symbol as having protected visibility. 305 MCSymbolAttr ProtectedVisibilityAttr; // Defaults to MCSA_Protected 306 307 //===--- Dwarf Emission Directives -----------------------------------===// 308 309 /// HasLEB128 - True if target asm supports leb128 directives. 310 bool HasLEB128; // Defaults to false. 311 312 /// SupportsDebugInformation - True if target supports emission of debugging 313 /// information. 314 bool SupportsDebugInformation; // Defaults to false. 315 316 /// SupportsExceptionHandling - True if target supports exception handling. 317 ExceptionHandling::ExceptionsType ExceptionsType; // Defaults to None 318 319 /// DwarfUsesInlineInfoSection - True if DwarfDebugInlineSection is used to 320 /// encode inline subroutine information. 321 bool DwarfUsesInlineInfoSection; // Defaults to false. 322 323 /// DwarfUsesRelocationsAcrossSections - True if Dwarf2 output generally 324 /// uses relocations for references to other .debug_* sections. 325 bool DwarfUsesRelocationsAcrossSections; 326 327 /// DwarfRegNumForCFI - True if dwarf register numbers are printed 328 /// instead of symbolic register names in .cfi_* directives. 329 bool DwarfRegNumForCFI; // Defaults to false; 330 331 //===--- Prologue State ----------------------------------------------===// 332 333 std::vector<MCCFIInstruction> InitialFrameState; 334 335 public: 336 explicit MCAsmInfo(); 337 virtual ~MCAsmInfo(); 338 339 // FIXME: move these methods to DwarfPrinter when the JIT stops using them. 340 static unsigned getSLEB128Size(int64_t Value); 341 static unsigned getULEB128Size(uint64_t Value); 342 343 /// getPointerSize - Get the pointer size in bytes. 344 unsigned getPointerSize() const { 345 return PointerSize; 346 } 347 348 /// getCalleeSaveStackSlotSize - Get the callee-saved register stack slot 349 /// size in bytes. 350 unsigned getCalleeSaveStackSlotSize() const { 351 return CalleeSaveStackSlotSize; 352 } 353 354 /// isLittleEndian - True if the target is little endian. 355 bool isLittleEndian() const { 356 return IsLittleEndian; 357 } 358 359 /// isStackGrowthDirectionUp - True if target stack grow up. 360 bool isStackGrowthDirectionUp() const { 361 return StackGrowsUp; 362 } 363 364 bool hasSubsectionsViaSymbols() const { return HasSubsectionsViaSymbols; } 365 366 // Data directive accessors. 367 // 368 const char *getData8bitsDirective() const { 369 return Data8bitsDirective; 370 } 371 const char *getData16bitsDirective() const { 372 return Data16bitsDirective; 373 } 374 const char *getData32bitsDirective() const { 375 return Data32bitsDirective; 376 } 377 const char *getData64bitsDirective() const { 378 return Data64bitsDirective; 379 } 380 const char *getGPRel64Directive() const { return GPRel64Directive; } 381 const char *getGPRel32Directive() const { return GPRel32Directive; } 382 383 /// getNonexecutableStackSection - Targets can implement this method to 384 /// specify a section to switch to if the translation unit doesn't have any 385 /// trampolines that require an executable stack. 386 virtual const MCSection *getNonexecutableStackSection(MCContext &Ctx) const{ 387 return 0; 388 } 389 390 virtual const MCExpr * 391 getExprForPersonalitySymbol(const MCSymbol *Sym, 392 unsigned Encoding, 393 MCStreamer &Streamer) const; 394 395 const MCExpr * 396 getExprForFDESymbol(const MCSymbol *Sym, 397 unsigned Encoding, 398 MCStreamer &Streamer) const; 399 400 bool usesSunStyleELFSectionSwitchSyntax() const { 401 return SunStyleELFSectionSwitchSyntax; 402 } 403 404 bool usesELFSectionDirectiveForBSS() const { 405 return UsesELFSectionDirectiveForBSS; 406 } 407 408 bool hasMicrosoftFastStdCallMangling() const { 409 return HasMicrosoftFastStdCallMangling; 410 } 411 412 bool needsDwarfSectionOffsetDirective() const { 413 return NeedsDwarfSectionOffsetDirective; 414 } 415 416 // Accessors. 417 // 418 bool hasMachoZeroFillDirective() const { return HasMachoZeroFillDirective; } 419 bool hasMachoTBSSDirective() const { return HasMachoTBSSDirective; } 420 bool hasStaticCtorDtorReferenceInStaticMode() const { 421 return HasStaticCtorDtorReferenceInStaticMode; 422 } 423 bool getLinkerRequiresNonEmptyDwarfLines() const { 424 return LinkerRequiresNonEmptyDwarfLines; 425 } 426 unsigned getMaxInstLength() const { 427 return MaxInstLength; 428 } 429 unsigned getMinInstAlignment() const { 430 return MinInstAlignment; 431 } 432 const char *getPCSymbol() const { 433 return PCSymbol; 434 } 435 const char *getSeparatorString() const { 436 return SeparatorString; 437 } 438 unsigned getCommentColumn() const { 439 return CommentColumn; 440 } 441 const char *getCommentString() const { 442 return CommentString; 443 } 444 const char *getLabelSuffix() const { 445 return LabelSuffix; 446 } 447 448 const char *getDebugLabelSuffix() const { 449 return DebugLabelSuffix; 450 } 451 452 const char *getGlobalPrefix() const { 453 return GlobalPrefix; 454 } 455 const char *getPrivateGlobalPrefix() const { 456 return PrivateGlobalPrefix; 457 } 458 const char *getLinkerPrivateGlobalPrefix() const { 459 return LinkerPrivateGlobalPrefix; 460 } 461 const char *getInlineAsmStart() const { 462 return InlineAsmStart; 463 } 464 const char *getInlineAsmEnd() const { 465 return InlineAsmEnd; 466 } 467 const char *getCode16Directive() const { 468 return Code16Directive; 469 } 470 const char *getCode32Directive() const { 471 return Code32Directive; 472 } 473 const char *getCode64Directive() const { 474 return Code64Directive; 475 } 476 unsigned getAssemblerDialect() const { 477 return AssemblerDialect; 478 } 479 bool doesAllowQuotesInName() const { 480 return AllowQuotesInName; 481 } 482 bool doesAllowNameToStartWithDigit() const { 483 return AllowNameToStartWithDigit; 484 } 485 bool doesAllowPeriodsInName() const { 486 return AllowPeriodsInName; 487 } 488 bool doesAllowUTF8() const { 489 return AllowUTF8; 490 } 491 bool doesSupportDataRegionDirectives() const { 492 return UseDataRegionDirectives; 493 } 494 const char *getZeroDirective() const { 495 return ZeroDirective; 496 } 497 const char *getAsciiDirective() const { 498 return AsciiDirective; 499 } 500 const char *getAscizDirective() const { 501 return AscizDirective; 502 } 503 const char *getAlignDirective() const { 504 return AlignDirective; 505 } 506 bool getAlignmentIsInBytes() const { 507 return AlignmentIsInBytes; 508 } 509 unsigned getTextAlignFillValue() const { 510 return TextAlignFillValue; 511 } 512 const char *getGlobalDirective() const { 513 return GlobalDirective; 514 } 515 const char *getExternDirective() const { 516 return ExternDirective; 517 } 518 bool hasSetDirective() const { return HasSetDirective; } 519 bool hasAggressiveSymbolFolding() const { 520 return HasAggressiveSymbolFolding; 521 } 522 bool getCOMMDirectiveAlignmentIsInBytes() const { 523 return COMMDirectiveAlignmentIsInBytes; 524 } 525 LCOMM::LCOMMType getLCOMMDirectiveAlignmentType() const { 526 return LCOMMDirectiveAlignmentType; 527 } 528 bool hasDotTypeDotSizeDirective() const {return HasDotTypeDotSizeDirective;} 529 bool hasSingleParameterDotFile() const { return HasSingleParameterDotFile; } 530 bool hasNoDeadStrip() const { return HasNoDeadStrip; } 531 bool hasSymbolResolver() const { return HasSymbolResolver; } 532 const char *getWeakRefDirective() const { return WeakRefDirective; } 533 const char *getWeakDefDirective() const { return WeakDefDirective; } 534 const char *getLinkOnceDirective() const { return LinkOnceDirective; } 535 536 MCSymbolAttr getHiddenVisibilityAttr() const { return HiddenVisibilityAttr;} 537 MCSymbolAttr getHiddenDeclarationVisibilityAttr() const { 538 return HiddenDeclarationVisibilityAttr; 539 } 540 MCSymbolAttr getProtectedVisibilityAttr() const { 541 return ProtectedVisibilityAttr; 542 } 543 bool hasLEB128() const { 544 return HasLEB128; 545 } 546 bool doesSupportDebugInformation() const { 547 return SupportsDebugInformation; 548 } 549 bool doesSupportExceptionHandling() const { 550 return ExceptionsType != ExceptionHandling::None; 551 } 552 ExceptionHandling::ExceptionsType getExceptionHandlingType() const { 553 return ExceptionsType; 554 } 555 bool isExceptionHandlingDwarf() const { 556 return 557 (ExceptionsType == ExceptionHandling::DwarfCFI || 558 ExceptionsType == ExceptionHandling::ARM || 559 ExceptionsType == ExceptionHandling::Win64); 560 } 561 bool doesDwarfUseInlineInfoSection() const { 562 return DwarfUsesInlineInfoSection; 563 } 564 bool doesDwarfUseRelocationsAcrossSections() const { 565 return DwarfUsesRelocationsAcrossSections; 566 } 567 bool useDwarfRegNumForCFI() const { 568 return DwarfRegNumForCFI; 569 } 570 571 void addInitialFrameState(const MCCFIInstruction &Inst) { 572 InitialFrameState.push_back(Inst); 573 } 574 575 const std::vector<MCCFIInstruction> &getInitialFrameState() const { 576 return InitialFrameState; 577 } 578 }; 579 } 580 581 #endif 582