MCAsmInfo.h revision b5e16af9ea04cc1f94ca631104e5e6be96546aa1
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/MCDirectives.h" 20#include <cassert> 21 22namespace llvm { 23 class MCSection; 24 class MCContext; 25 26 /// MCAsmInfo - This class is intended to be used as a base class for asm 27 /// properties and features specific to the target. 28 namespace ExceptionHandling { 29 enum ExceptionsType { None, DwarfTable, DwarfCFI, SjLj, ARM }; 30 } 31 32 class MCAsmInfo { 33 protected: 34 //===------------------------------------------------------------------===// 35 // Properties to be set by the target writer, used to configure asm printer. 36 // 37 38 /// HasSubsectionsViaSymbols - True if this target has the MachO 39 /// .subsections_via_symbols directive. 40 bool HasSubsectionsViaSymbols; // Default is false. 41 42 /// HasMachoZeroFillDirective - True if this is a MachO target that supports 43 /// the macho-specific .zerofill directive for emitting BSS Symbols. 44 bool HasMachoZeroFillDirective; // Default is false. 45 46 /// HasMachoTBSSDirective - True if this is a MachO target that supports 47 /// the macho-specific .tbss directive for emitting thread local BSS Symbols 48 bool HasMachoTBSSDirective; // Default is false. 49 50 /// HasStaticCtorDtorReferenceInStaticMode - True if the compiler should 51 /// emit a ".reference .constructors_used" or ".reference .destructors_used" 52 /// directive after the a static ctor/dtor list. This directive is only 53 /// emitted in Static relocation model. 54 bool HasStaticCtorDtorReferenceInStaticMode; // Default is false. 55 56 /// LinkerRequiresNonEmptyDwarfLines - True if the linker has a bug and 57 /// requires that the debug_line section be of a minimum size. In practice 58 /// such a linker requires a non empty line sequence if a file is present. 59 bool LinkerRequiresNonEmptyDwarfLines; // Default to false. 60 61 /// MaxInstLength - This is the maximum possible length of an instruction, 62 /// which is needed to compute the size of an inline asm. 63 unsigned MaxInstLength; // Defaults to 4. 64 65 /// PCSymbol - The symbol used to represent the current PC. Used in PC 66 /// relative expressions. 67 const char *PCSymbol; // Defaults to "$". 68 69 /// SeparatorChar - This character, if specified, is used to separate 70 /// instructions from each other when on the same line. This is used to 71 /// measure inline asm instructions. 72 char SeparatorChar; // Defaults to ';' 73 74 /// CommentColumn - This indicates the comment num (zero-based) at 75 /// which asm comments should be printed. 76 unsigned CommentColumn; // Defaults to 40 77 78 /// CommentString - This indicates the comment character used by the 79 /// assembler. 80 const char *CommentString; // Defaults to "#" 81 82 /// LabelSuffix - This is appended to emitted labels. 83 const char *LabelSuffix; // Defaults to ":" 84 85 /// GlobalPrefix - If this is set to a non-empty string, it is prepended 86 /// onto all global symbols. This is often used for "_" or ".". 87 const char *GlobalPrefix; // Defaults to "" 88 89 /// PrivateGlobalPrefix - This prefix is used for globals like constant 90 /// pool entries that are completely private to the .s file and should not 91 /// have names in the .o file. This is often "." or "L". 92 const char *PrivateGlobalPrefix; // Defaults to "." 93 94 /// LinkerPrivateGlobalPrefix - This prefix is used for symbols that should 95 /// be passed through the assembler but be removed by the linker. This 96 /// is "l" on Darwin, currently used for some ObjC metadata. 97 const char *LinkerPrivateGlobalPrefix; // Defaults to "" 98 99 /// InlineAsmStart/End - If these are nonempty, they contain a directive to 100 /// emit before and after an inline assembly statement. 101 const char *InlineAsmStart; // Defaults to "#APP\n" 102 const char *InlineAsmEnd; // Defaults to "#NO_APP\n" 103 104 /// AssemblerDialect - Which dialect of an assembler variant to use. 105 unsigned AssemblerDialect; // Defaults to 0 106 107 /// AllowQuotesInName - This is true if the assembler allows for complex 108 /// symbol names to be surrounded in quotes. This defaults to false. 109 bool AllowQuotesInName; 110 111 /// AllowNameToStartWithDigit - This is true if the assembler allows symbol 112 /// names to start with a digit (e.g., "0x0021"). This defaults to false. 113 bool AllowNameToStartWithDigit; 114 115 /// AllowPeriodsInName - This is true if the assembler allows periods in 116 /// symbol names. This defaults to true. 117 bool AllowPeriodsInName; 118 119 //===--- Data Emission Directives -------------------------------------===// 120 121 /// ZeroDirective - this should be set to the directive used to get some 122 /// number of zero bytes emitted to the current section. Common cases are 123 /// "\t.zero\t" and "\t.space\t". If this is set to null, the 124 /// Data*bitsDirective's will be used to emit zero bytes. 125 const char *ZeroDirective; // Defaults to "\t.zero\t" 126 127 /// AsciiDirective - This directive allows emission of an ascii string with 128 /// the standard C escape characters embedded into it. 129 const char *AsciiDirective; // Defaults to "\t.ascii\t" 130 131 /// AscizDirective - If not null, this allows for special handling of 132 /// zero terminated strings on this target. This is commonly supported as 133 /// ".asciz". If a target doesn't support this, it can be set to null. 134 const char *AscizDirective; // Defaults to "\t.asciz\t" 135 136 /// DataDirectives - These directives are used to output some unit of 137 /// integer data to the current section. If a data directive is set to 138 /// null, smaller data directives will be used to emit the large sizes. 139 const char *Data8bitsDirective; // Defaults to "\t.byte\t" 140 const char *Data16bitsDirective; // Defaults to "\t.short\t" 141 const char *Data32bitsDirective; // Defaults to "\t.long\t" 142 const char *Data64bitsDirective; // Defaults to "\t.quad\t" 143 144 /// GPRel32Directive - if non-null, a directive that is used to emit a word 145 /// which should be relocated as a 32-bit GP-relative offset, e.g. .gpword 146 /// on Mips or .gprel32 on Alpha. 147 const char *GPRel32Directive; // Defaults to NULL. 148 149 /// getDataASDirective - Return the directive that should be used to emit 150 /// data of the specified size to the specified numeric address space. 151 virtual const char *getDataASDirective(unsigned Size, unsigned AS) const { 152 assert(AS != 0 && "Don't know the directives for default addr space"); 153 return 0; 154 } 155 156 /// SunStyleELFSectionSwitchSyntax - This is true if this target uses "Sun 157 /// Style" syntax for section switching ("#alloc,#write" etc) instead of the 158 /// normal ELF syntax (,"a,w") in .section directives. 159 bool SunStyleELFSectionSwitchSyntax; // Defaults to false. 160 161 /// UsesELFSectionDirectiveForBSS - This is true if this target uses ELF 162 /// '.section' directive before the '.bss' one. It's used for PPC/Linux 163 /// which doesn't support the '.bss' directive only. 164 bool UsesELFSectionDirectiveForBSS; // Defaults to false. 165 166 /// HasMicrosoftFastStdCallMangling - True if this target uses microsoft 167 /// style mangling for functions with X86_StdCall/X86_FastCall calling 168 /// convention. 169 bool HasMicrosoftFastStdCallMangling; // Defaults to false. 170 171 //===--- Alignment Information ----------------------------------------===// 172 173 /// AlignDirective - The directive used to emit round up to an alignment 174 /// boundary. 175 /// 176 const char *AlignDirective; // Defaults to "\t.align\t" 177 178 /// AlignmentIsInBytes - If this is true (the default) then the asmprinter 179 /// emits ".align N" directives, where N is the number of bytes to align to. 180 /// Otherwise, it emits ".align log2(N)", e.g. 3 to align to an 8 byte 181 /// boundary. 182 bool AlignmentIsInBytes; // Defaults to true 183 184 /// TextAlignFillValue - If non-zero, this is used to fill the executable 185 /// space created as the result of a alignment directive. 186 unsigned TextAlignFillValue; // Defaults to 0 187 188 //===--- Global Variable Emission Directives --------------------------===// 189 190 /// GlobalDirective - This is the directive used to declare a global entity. 191 /// 192 const char *GlobalDirective; // Defaults to NULL. 193 194 /// ExternDirective - This is the directive used to declare external 195 /// globals. 196 /// 197 const char *ExternDirective; // Defaults to NULL. 198 199 /// HasSetDirective - True if the assembler supports the .set directive. 200 bool HasSetDirective; // Defaults to true. 201 202 /// HasAggressiveSymbolFolding - False if the assembler requires that we use 203 /// Lc = a - b 204 /// .long Lc 205 /// instead of 206 /// .long a - b 207 bool HasAggressiveSymbolFolding; // Defaults to true. 208 209 /// HasLCOMMDirective - This is true if the target supports the .lcomm 210 /// directive. 211 bool HasLCOMMDirective; // Defaults to false. 212 213 /// COMMDirectiveAlignmentIsInBytes - True is COMMDirective's optional 214 /// alignment is to be specified in bytes instead of log2(n). 215 bool COMMDirectiveAlignmentIsInBytes; // Defaults to true; 216 217 /// HasDotTypeDotSizeDirective - True if the target has .type and .size 218 /// directives, this is true for most ELF targets. 219 bool HasDotTypeDotSizeDirective; // Defaults to true. 220 221 /// HasSingleParameterDotFile - True if the target has a single parameter 222 /// .file directive, this is true for ELF targets. 223 bool HasSingleParameterDotFile; // Defaults to true. 224 225 /// HasNoDeadStrip - True if this target supports the MachO .no_dead_strip 226 /// directive. 227 bool HasNoDeadStrip; // Defaults to false. 228 229 /// HasSymbolResolver - True if this target supports the MachO 230 /// .symbol_resolver directive. 231 bool HasSymbolResolver; // Defaults to false. 232 233 /// WeakRefDirective - This directive, if non-null, is used to declare a 234 /// global as being a weak undefined symbol. 235 const char *WeakRefDirective; // Defaults to NULL. 236 237 /// WeakDefDirective - This directive, if non-null, is used to declare a 238 /// global as being a weak defined symbol. 239 const char *WeakDefDirective; // Defaults to NULL. 240 241 /// LinkOnceDirective - This directive, if non-null is used to declare a 242 /// global as being a weak defined symbol. This is used on cygwin/mingw. 243 const char *LinkOnceDirective; // Defaults to NULL. 244 245 /// HiddenVisibilityAttr - This attribute, if not MCSA_Invalid, is used to 246 /// declare a symbol as having hidden visibility. 247 MCSymbolAttr HiddenVisibilityAttr; // Defaults to MCSA_Hidden. 248 249 /// HiddenDeclarationVisibilityAttr - This attribute, if not MCSA_Invalid, 250 /// is used to declare an undefined symbol as having hidden visibility. 251 MCSymbolAttr HiddenDeclarationVisibilityAttr; // Defaults to MCSA_Hidden. 252 253 254 /// ProtectedVisibilityAttr - This attribute, if not MCSA_Invalid, is used 255 /// to declare a symbol as having protected visibility. 256 MCSymbolAttr ProtectedVisibilityAttr; // Defaults to MCSA_Protected 257 258 //===--- Dwarf Emission Directives -----------------------------------===// 259 260 /// HasLEB128 - True if target asm supports leb128 directives. 261 bool HasLEB128; // Defaults to false. 262 263 /// SupportsDebugInformation - True if target supports emission of debugging 264 /// information. 265 bool SupportsDebugInformation; // Defaults to false. 266 267 /// SupportsExceptionHandling - True if target supports exception handling. 268 ExceptionHandling::ExceptionsType ExceptionsType; // Defaults to None 269 270 /// RequiresFrameSection - true if the Dwarf2 output needs a frame section 271 bool DwarfRequiresFrameSection; // Defaults to true. 272 273 /// DwarfUsesInlineInfoSection - True if DwarfDebugInlineSection is used to 274 /// encode inline subroutine information. 275 bool DwarfUsesInlineInfoSection; // Defaults to false. 276 277 /// DwarfSectionOffsetDirective - Special section offset directive. 278 const char* DwarfSectionOffsetDirective; // Defaults to NULL 279 280 /// DwarfUsesAbsoluteLabelForStmtList - True if DW_AT_stmt_list needs 281 /// absolute label instead of offset. 282 bool DwarfUsesAbsoluteLabelForStmtList; // Defaults to true; 283 284 // DwarfUsesLabelOffsetDifference - True if Dwarf2 output can 285 // use EmitLabelOffsetDifference. 286 bool DwarfUsesLabelOffsetForRanges; 287 288 //===--- CBE Asm Translation Table -----------------------------------===// 289 290 const char *const *AsmTransCBE; // Defaults to empty 291 292 public: 293 explicit MCAsmInfo(); 294 virtual ~MCAsmInfo(); 295 296 // FIXME: move these methods to DwarfPrinter when the JIT stops using them. 297 static unsigned getSLEB128Size(int Value); 298 static unsigned getULEB128Size(unsigned Value); 299 300 bool hasSubsectionsViaSymbols() const { return HasSubsectionsViaSymbols; } 301 302 // Data directive accessors. 303 // 304 const char *getData8bitsDirective(unsigned AS = 0) const { 305 return AS == 0 ? Data8bitsDirective : getDataASDirective(8, AS); 306 } 307 const char *getData16bitsDirective(unsigned AS = 0) const { 308 return AS == 0 ? Data16bitsDirective : getDataASDirective(16, AS); 309 } 310 const char *getData32bitsDirective(unsigned AS = 0) const { 311 return AS == 0 ? Data32bitsDirective : getDataASDirective(32, AS); 312 } 313 const char *getData64bitsDirective(unsigned AS = 0) const { 314 return AS == 0 ? Data64bitsDirective : getDataASDirective(64, AS); 315 } 316 const char *getGPRel32Directive() const { return GPRel32Directive; } 317 318 /// getNonexecutableStackSection - Targets can implement this method to 319 /// specify a section to switch to if the translation unit doesn't have any 320 /// trampolines that require an executable stack. 321 virtual const MCSection *getNonexecutableStackSection(MCContext &Ctx) const{ 322 return 0; 323 } 324 325 bool usesSunStyleELFSectionSwitchSyntax() const { 326 return SunStyleELFSectionSwitchSyntax; 327 } 328 329 bool usesELFSectionDirectiveForBSS() const { 330 return UsesELFSectionDirectiveForBSS; 331 } 332 333 bool hasMicrosoftFastStdCallMangling() const { 334 return HasMicrosoftFastStdCallMangling; 335 } 336 337 // Accessors. 338 // 339 bool hasMachoZeroFillDirective() const { return HasMachoZeroFillDirective; } 340 bool hasMachoTBSSDirective() const { return HasMachoTBSSDirective; } 341 bool hasStaticCtorDtorReferenceInStaticMode() const { 342 return HasStaticCtorDtorReferenceInStaticMode; 343 } 344 bool getLinkerRequiresNonEmptyDwarfLines() const { 345 return LinkerRequiresNonEmptyDwarfLines; 346 } 347 unsigned getMaxInstLength() const { 348 return MaxInstLength; 349 } 350 const char *getPCSymbol() const { 351 return PCSymbol; 352 } 353 char getSeparatorChar() const { 354 return SeparatorChar; 355 } 356 unsigned getCommentColumn() const { 357 return CommentColumn; 358 } 359 const char *getCommentString() const { 360 return CommentString; 361 } 362 const char *getLabelSuffix() const { 363 return LabelSuffix; 364 } 365 const char *getGlobalPrefix() const { 366 return GlobalPrefix; 367 } 368 const char *getPrivateGlobalPrefix() const { 369 return PrivateGlobalPrefix; 370 } 371 const char *getLinkerPrivateGlobalPrefix() const { 372 return LinkerPrivateGlobalPrefix; 373 } 374 const char *getInlineAsmStart() const { 375 return InlineAsmStart; 376 } 377 const char *getInlineAsmEnd() const { 378 return InlineAsmEnd; 379 } 380 unsigned getAssemblerDialect() const { 381 return AssemblerDialect; 382 } 383 bool doesAllowQuotesInName() const { 384 return AllowQuotesInName; 385 } 386 bool doesAllowNameToStartWithDigit() const { 387 return AllowNameToStartWithDigit; 388 } 389 bool doesAllowPeriodsInName() const { 390 return AllowPeriodsInName; 391 } 392 const char *getZeroDirective() const { 393 return ZeroDirective; 394 } 395 const char *getAsciiDirective() const { 396 return AsciiDirective; 397 } 398 const char *getAscizDirective() const { 399 return AscizDirective; 400 } 401 const char *getAlignDirective() const { 402 return AlignDirective; 403 } 404 bool getAlignmentIsInBytes() const { 405 return AlignmentIsInBytes; 406 } 407 unsigned getTextAlignFillValue() const { 408 return TextAlignFillValue; 409 } 410 const char *getGlobalDirective() const { 411 return GlobalDirective; 412 } 413 const char *getExternDirective() const { 414 return ExternDirective; 415 } 416 bool hasSetDirective() const { return HasSetDirective; } 417 bool hasAggressiveSymbolFolding() const { 418 return HasAggressiveSymbolFolding; 419 } 420 bool hasLCOMMDirective() const { return HasLCOMMDirective; } 421 bool hasDotTypeDotSizeDirective() const {return HasDotTypeDotSizeDirective;} 422 bool getCOMMDirectiveAlignmentIsInBytes() const { 423 return COMMDirectiveAlignmentIsInBytes; 424 } 425 bool hasSingleParameterDotFile() const { return HasSingleParameterDotFile; } 426 bool hasNoDeadStrip() const { return HasNoDeadStrip; } 427 bool hasSymbolResolver() const { return HasSymbolResolver; } 428 const char *getWeakRefDirective() const { return WeakRefDirective; } 429 const char *getWeakDefDirective() const { return WeakDefDirective; } 430 const char *getLinkOnceDirective() const { return LinkOnceDirective; } 431 432 MCSymbolAttr getHiddenVisibilityAttr() const { return HiddenVisibilityAttr;} 433 MCSymbolAttr getHiddenDeclarationVisibilityAttr() const { 434 return HiddenDeclarationVisibilityAttr; 435 } 436 MCSymbolAttr getProtectedVisibilityAttr() const { 437 return ProtectedVisibilityAttr; 438 } 439 bool hasLEB128() const { 440 return HasLEB128; 441 } 442 bool doesSupportDebugInformation() const { 443 return SupportsDebugInformation; 444 } 445 bool doesSupportExceptionHandling() const { 446 return ExceptionsType != ExceptionHandling::None; 447 } 448 ExceptionHandling::ExceptionsType getExceptionHandlingType() const { 449 return ExceptionsType; 450 } 451 bool isExceptionHandlingDwarf() const { 452 return 453 (ExceptionsType == ExceptionHandling::DwarfTable || 454 ExceptionsType == ExceptionHandling::DwarfCFI || 455 ExceptionsType == ExceptionHandling::ARM); 456 } 457 458 bool doesDwarfRequireFrameSection() const { 459 return DwarfRequiresFrameSection; 460 } 461 bool doesDwarfUsesInlineInfoSection() const { 462 return DwarfUsesInlineInfoSection; 463 } 464 const char *getDwarfSectionOffsetDirective() const { 465 return DwarfSectionOffsetDirective; 466 } 467 bool doesDwarfUsesAbsoluteLabelForStmtList() const { 468 return DwarfUsesAbsoluteLabelForStmtList; 469 } 470 bool doesDwarfUsesLabelOffsetForRanges() const { 471 return DwarfUsesLabelOffsetForRanges; 472 } 473 const char *const *getAsmCBE() const { 474 return AsmTransCBE; 475 } 476 }; 477} 478 479#endif 480