MCAsmInfo.h revision 263508
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 25namespace 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 /// DollarIsPC - The '$' token, when not referencing an identifier or 97 /// constant, refers to the current PC. 98 bool DollarIsPC; // Defaults to false. 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 /// \brief This is true if the assembler allows @ characters in symbol 148 /// names. Defaults to false. 149 bool AllowAtInName; 150 151 /// UseDataRegionDirectives - This is true if data region markers should 152 /// be printed as ".data_region/.end_data_region" directives. If false, 153 /// use "$d/$a" labels instead. 154 bool UseDataRegionDirectives; 155 156 //===--- Data Emission Directives -------------------------------------===// 157 158 /// ZeroDirective - this should be set to the directive used to get some 159 /// number of zero bytes emitted to the current section. Common cases are 160 /// "\t.zero\t" and "\t.space\t". If this is set to null, the 161 /// Data*bitsDirective's will be used to emit zero bytes. 162 const char *ZeroDirective; // Defaults to "\t.zero\t" 163 164 /// AsciiDirective - This directive allows emission of an ascii string with 165 /// the standard C escape characters embedded into it. 166 const char *AsciiDirective; // Defaults to "\t.ascii\t" 167 168 /// AscizDirective - If not null, this allows for special handling of 169 /// zero terminated strings on this target. This is commonly supported as 170 /// ".asciz". If a target doesn't support this, it can be set to null. 171 const char *AscizDirective; // Defaults to "\t.asciz\t" 172 173 /// DataDirectives - These directives are used to output some unit of 174 /// integer data to the current section. If a data directive is set to 175 /// null, smaller data directives will be used to emit the large sizes. 176 const char *Data8bitsDirective; // Defaults to "\t.byte\t" 177 const char *Data16bitsDirective; // Defaults to "\t.short\t" 178 const char *Data32bitsDirective; // Defaults to "\t.long\t" 179 const char *Data64bitsDirective; // Defaults to "\t.quad\t" 180 181 /// GPRel64Directive - if non-null, a directive that is used to emit a word 182 /// which should be relocated as a 64-bit GP-relative offset, e.g. .gpdword 183 /// on Mips. 184 const char *GPRel64Directive; // Defaults to NULL. 185 186 /// GPRel32Directive - if non-null, a directive that is used to emit a word 187 /// which should be relocated as a 32-bit GP-relative offset, e.g. .gpword 188 /// on Mips or .gprel32 on Alpha. 189 const char *GPRel32Directive; // Defaults to NULL. 190 191 /// SunStyleELFSectionSwitchSyntax - This is true if this target uses "Sun 192 /// Style" syntax for section switching ("#alloc,#write" etc) instead of the 193 /// normal ELF syntax (,"a,w") in .section directives. 194 bool SunStyleELFSectionSwitchSyntax; // Defaults to false. 195 196 /// UsesELFSectionDirectiveForBSS - This is true if this target uses ELF 197 /// '.section' directive before the '.bss' one. It's used for PPC/Linux 198 /// which doesn't support the '.bss' directive only. 199 bool UsesELFSectionDirectiveForBSS; // Defaults to false. 200 201 /// HasMicrosoftFastStdCallMangling - True if this target uses microsoft 202 /// style mangling for functions with X86_StdCall/X86_FastCall calling 203 /// convention. 204 bool HasMicrosoftFastStdCallMangling; // Defaults to false. 205 206 bool NeedsDwarfSectionOffsetDirective; 207 208 //===--- Alignment Information ----------------------------------------===// 209 210 /// AlignDirective - The directive used to emit round up to an alignment 211 /// boundary. 212 /// 213 const char *AlignDirective; // Defaults to "\t.align\t" 214 215 /// AlignmentIsInBytes - If this is true (the default) then the asmprinter 216 /// emits ".align N" directives, where N is the number of bytes to align to. 217 /// Otherwise, it emits ".align log2(N)", e.g. 3 to align to an 8 byte 218 /// boundary. 219 bool AlignmentIsInBytes; // Defaults to true 220 221 /// TextAlignFillValue - If non-zero, this is used to fill the executable 222 /// space created as the result of a alignment directive. 223 unsigned TextAlignFillValue; // Defaults to 0 224 225 //===--- Global Variable Emission Directives --------------------------===// 226 227 /// GlobalDirective - This is the directive used to declare a global entity. 228 /// 229 const char *GlobalDirective; // Defaults to NULL. 230 231 /// HasSetDirective - True if the assembler supports the .set directive. 232 bool HasSetDirective; // Defaults to true. 233 234 /// HasAggressiveSymbolFolding - False if the assembler requires that we use 235 /// Lc = a - b 236 /// .long Lc 237 /// instead of 238 /// .long a - b 239 bool HasAggressiveSymbolFolding; // Defaults to true. 240 241 /// COMMDirectiveAlignmentIsInBytes - True is .comm's and .lcomms optional 242 /// alignment is to be specified in bytes instead of log2(n). 243 bool COMMDirectiveAlignmentIsInBytes; // Defaults to true; 244 245 /// LCOMMDirectiveAlignment - Describes if the .lcomm directive for the 246 /// target supports an alignment argument and how it is interpreted. 247 LCOMM::LCOMMType LCOMMDirectiveAlignmentType; // Defaults to NoAlignment. 248 249 /// HasDotTypeDotSizeDirective - True if the target has .type and .size 250 /// directives, this is true for most ELF targets. 251 bool HasDotTypeDotSizeDirective; // Defaults to true. 252 253 /// HasSingleParameterDotFile - True if the target has a single parameter 254 /// .file directive, this is true for ELF targets. 255 bool HasSingleParameterDotFile; // Defaults to true. 256 257 /// hasIdentDirective - True if the target has a .ident directive, this is 258 /// true for ELF targets. 259 bool HasIdentDirective; // Defaults to false. 260 261 /// HasNoDeadStrip - True if this target supports the MachO .no_dead_strip 262 /// directive. 263 bool HasNoDeadStrip; // Defaults to false. 264 265 /// WeakRefDirective - This directive, if non-null, is used to declare a 266 /// global as being a weak undefined symbol. 267 const char *WeakRefDirective; // Defaults to NULL. 268 269 /// WeakDefDirective - This directive, if non-null, is used to declare a 270 /// global as being a weak defined symbol. 271 const char *WeakDefDirective; // Defaults to NULL. 272 273 /// LinkOnceDirective - This directive, if non-null is used to declare a 274 /// global as being a weak defined symbol. This is used on cygwin/mingw. 275 const char *LinkOnceDirective; // Defaults to NULL. 276 277 /// HiddenVisibilityAttr - This attribute, if not MCSA_Invalid, is used to 278 /// declare a symbol as having hidden visibility. 279 MCSymbolAttr HiddenVisibilityAttr; // Defaults to MCSA_Hidden. 280 281 /// HiddenDeclarationVisibilityAttr - This attribute, if not MCSA_Invalid, 282 /// is used to declare an undefined symbol as having hidden visibility. 283 MCSymbolAttr HiddenDeclarationVisibilityAttr; // Defaults to MCSA_Hidden. 284 285 286 /// ProtectedVisibilityAttr - This attribute, if not MCSA_Invalid, is used 287 /// to declare a symbol as having protected visibility. 288 MCSymbolAttr ProtectedVisibilityAttr; // Defaults to MCSA_Protected 289 290 //===--- Dwarf Emission Directives -----------------------------------===// 291 292 /// HasLEB128 - True if target asm supports leb128 directives. 293 bool HasLEB128; // Defaults to false. 294 295 /// SupportsDebugInformation - True if target supports emission of debugging 296 /// information. 297 bool SupportsDebugInformation; // Defaults to false. 298 299 /// SupportsExceptionHandling - True if target supports exception handling. 300 ExceptionHandling::ExceptionsType ExceptionsType; // Defaults to None 301 302 /// DwarfUsesRelocationsAcrossSections - True if Dwarf2 output generally 303 /// uses relocations for references to other .debug_* sections. 304 bool DwarfUsesRelocationsAcrossSections; 305 306 /// DwarfRegNumForCFI - True if dwarf register numbers are printed 307 /// instead of symbolic register names in .cfi_* directives. 308 bool DwarfRegNumForCFI; // Defaults to false; 309 310 //===--- Prologue State ----------------------------------------------===// 311 312 std::vector<MCCFIInstruction> InitialFrameState; 313 314 public: 315 explicit MCAsmInfo(); 316 virtual ~MCAsmInfo(); 317 318 // FIXME: move these methods to DwarfPrinter when the JIT stops using them. 319 static unsigned getSLEB128Size(int64_t Value); 320 static unsigned getULEB128Size(uint64_t Value); 321 322 /// getPointerSize - Get the pointer size in bytes. 323 unsigned getPointerSize() const { 324 return PointerSize; 325 } 326 327 /// getCalleeSaveStackSlotSize - Get the callee-saved register stack slot 328 /// size in bytes. 329 unsigned getCalleeSaveStackSlotSize() const { 330 return CalleeSaveStackSlotSize; 331 } 332 333 /// isLittleEndian - True if the target is little endian. 334 bool isLittleEndian() const { 335 return IsLittleEndian; 336 } 337 338 /// isStackGrowthDirectionUp - True if target stack grow up. 339 bool isStackGrowthDirectionUp() const { 340 return StackGrowsUp; 341 } 342 343 bool hasSubsectionsViaSymbols() const { return HasSubsectionsViaSymbols; } 344 345 // Data directive accessors. 346 // 347 const char *getData8bitsDirective() const { 348 return Data8bitsDirective; 349 } 350 const char *getData16bitsDirective() const { 351 return Data16bitsDirective; 352 } 353 const char *getData32bitsDirective() const { 354 return Data32bitsDirective; 355 } 356 const char *getData64bitsDirective() const { 357 return Data64bitsDirective; 358 } 359 const char *getGPRel64Directive() const { return GPRel64Directive; } 360 const char *getGPRel32Directive() const { return GPRel32Directive; } 361 362 /// getNonexecutableStackSection - Targets can implement this method to 363 /// specify a section to switch to if the translation unit doesn't have any 364 /// trampolines that require an executable stack. 365 virtual const MCSection *getNonexecutableStackSection(MCContext &Ctx) const{ 366 return 0; 367 } 368 369 virtual const MCExpr * 370 getExprForPersonalitySymbol(const MCSymbol *Sym, 371 unsigned Encoding, 372 MCStreamer &Streamer) const; 373 374 const MCExpr * 375 getExprForFDESymbol(const MCSymbol *Sym, 376 unsigned Encoding, 377 MCStreamer &Streamer) const; 378 379 bool usesSunStyleELFSectionSwitchSyntax() const { 380 return SunStyleELFSectionSwitchSyntax; 381 } 382 383 bool usesELFSectionDirectiveForBSS() const { 384 return UsesELFSectionDirectiveForBSS; 385 } 386 387 bool hasMicrosoftFastStdCallMangling() const { 388 return HasMicrosoftFastStdCallMangling; 389 } 390 391 bool needsDwarfSectionOffsetDirective() const { 392 return NeedsDwarfSectionOffsetDirective; 393 } 394 395 // Accessors. 396 // 397 bool hasMachoZeroFillDirective() const { return HasMachoZeroFillDirective; } 398 bool hasMachoTBSSDirective() const { return HasMachoTBSSDirective; } 399 bool hasStaticCtorDtorReferenceInStaticMode() const { 400 return HasStaticCtorDtorReferenceInStaticMode; 401 } 402 bool getLinkerRequiresNonEmptyDwarfLines() const { 403 return LinkerRequiresNonEmptyDwarfLines; 404 } 405 unsigned getMaxInstLength() const { 406 return MaxInstLength; 407 } 408 unsigned getMinInstAlignment() const { 409 return MinInstAlignment; 410 } 411 bool getDollarIsPC() const { 412 return DollarIsPC; 413 } 414 const char *getSeparatorString() const { 415 return SeparatorString; 416 } 417 unsigned getCommentColumn() const { 418 return CommentColumn; 419 } 420 const char *getCommentString() const { 421 return CommentString; 422 } 423 const char *getLabelSuffix() const { 424 return LabelSuffix; 425 } 426 427 const char *getDebugLabelSuffix() const { 428 return DebugLabelSuffix; 429 } 430 431 const char *getGlobalPrefix() const { 432 return GlobalPrefix; 433 } 434 const char *getPrivateGlobalPrefix() const { 435 return PrivateGlobalPrefix; 436 } 437 const char *getLinkerPrivateGlobalPrefix() const { 438 return LinkerPrivateGlobalPrefix; 439 } 440 const char *getInlineAsmStart() const { 441 return InlineAsmStart; 442 } 443 const char *getInlineAsmEnd() const { 444 return InlineAsmEnd; 445 } 446 const char *getCode16Directive() const { 447 return Code16Directive; 448 } 449 const char *getCode32Directive() const { 450 return Code32Directive; 451 } 452 const char *getCode64Directive() const { 453 return Code64Directive; 454 } 455 unsigned getAssemblerDialect() const { 456 return AssemblerDialect; 457 } 458 bool doesAllowAtInName() const { 459 return AllowAtInName; 460 } 461 bool doesSupportDataRegionDirectives() const { 462 return UseDataRegionDirectives; 463 } 464 const char *getZeroDirective() const { 465 return ZeroDirective; 466 } 467 const char *getAsciiDirective() const { 468 return AsciiDirective; 469 } 470 const char *getAscizDirective() const { 471 return AscizDirective; 472 } 473 const char *getAlignDirective() const { 474 return AlignDirective; 475 } 476 bool getAlignmentIsInBytes() const { 477 return AlignmentIsInBytes; 478 } 479 unsigned getTextAlignFillValue() const { 480 return TextAlignFillValue; 481 } 482 const char *getGlobalDirective() const { 483 return GlobalDirective; 484 } 485 bool hasSetDirective() const { return HasSetDirective; } 486 bool hasAggressiveSymbolFolding() const { 487 return HasAggressiveSymbolFolding; 488 } 489 bool getCOMMDirectiveAlignmentIsInBytes() const { 490 return COMMDirectiveAlignmentIsInBytes; 491 } 492 LCOMM::LCOMMType getLCOMMDirectiveAlignmentType() const { 493 return LCOMMDirectiveAlignmentType; 494 } 495 bool hasDotTypeDotSizeDirective() const {return HasDotTypeDotSizeDirective;} 496 bool hasSingleParameterDotFile() const { return HasSingleParameterDotFile; } 497 bool hasIdentDirective() const { return HasIdentDirective; } 498 bool hasNoDeadStrip() const { return HasNoDeadStrip; } 499 const char *getWeakRefDirective() const { return WeakRefDirective; } 500 const char *getWeakDefDirective() const { return WeakDefDirective; } 501 const char *getLinkOnceDirective() const { return LinkOnceDirective; } 502 503 MCSymbolAttr getHiddenVisibilityAttr() const { return HiddenVisibilityAttr;} 504 MCSymbolAttr getHiddenDeclarationVisibilityAttr() const { 505 return HiddenDeclarationVisibilityAttr; 506 } 507 MCSymbolAttr getProtectedVisibilityAttr() const { 508 return ProtectedVisibilityAttr; 509 } 510 bool hasLEB128() const { 511 return HasLEB128; 512 } 513 bool doesSupportDebugInformation() const { 514 return SupportsDebugInformation; 515 } 516 bool doesSupportExceptionHandling() const { 517 return ExceptionsType != ExceptionHandling::None; 518 } 519 ExceptionHandling::ExceptionsType getExceptionHandlingType() const { 520 return ExceptionsType; 521 } 522 bool isExceptionHandlingDwarf() const { 523 return 524 (ExceptionsType == ExceptionHandling::DwarfCFI || 525 ExceptionsType == ExceptionHandling::ARM || 526 ExceptionsType == ExceptionHandling::Win64); 527 } 528 bool doesDwarfUseRelocationsAcrossSections() const { 529 return DwarfUsesRelocationsAcrossSections; 530 } 531 bool useDwarfRegNumForCFI() const { 532 return DwarfRegNumForCFI; 533 } 534 535 void addInitialFrameState(const MCCFIInstruction &Inst) { 536 InitialFrameState.push_back(Inst); 537 } 538 539 const std::vector<MCCFIInstruction> &getInitialFrameState() const { 540 return InitialFrameState; 541 } 542 }; 543} 544 545#endif 546