MCAsmInfo.h revision 767b1be3900bdc693aa0ad3e554ba034845f67f7
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 { enum ExceptionsType { None, Dwarf, SjLj }; } 29 30 class MCAsmInfo { 31 protected: 32 //===------------------------------------------------------------------===// 33 // Properties to be set by the target writer, used to configure asm printer. 34 // 35 36 /// HasSubsectionsViaSymbols - True if this target has the MachO 37 /// .subsections_via_symbols directive. 38 bool HasSubsectionsViaSymbols; // Default is false. 39 40 /// HasMachoZeroFillDirective - True if this is a MachO target that supports 41 /// the macho-specific .zerofill directive for emitting BSS Symbols. 42 bool HasMachoZeroFillDirective; // Default is false. 43 44 /// HasMachoTBSSDirective - True if this is a MachO target that supports 45 /// the macho-specific .tbss directive for emitting thread local BSS Symbols 46 bool HasMachoTBSSDirective; // Default is false. 47 48 /// HasStaticCtorDtorReferenceInStaticMode - True if the compiler should 49 /// emit a ".reference .constructors_used" or ".reference .destructors_used" 50 /// directive after the a static ctor/dtor list. This directive is only 51 /// emitted in Static relocation model. 52 bool HasStaticCtorDtorReferenceInStaticMode; // Default is false. 53 54 /// LinkerRequiresNonEmptyDwarfLines - True if the linker has a bug and 55 /// requires that the debug_line section be of a minimum size. In practice 56 /// such a linker requires a non empty line sequence if a file is present. 57 bool LinkerRequiresNonEmptyDwarfLines; // Default to false. 58 59 /// MaxInstLength - This is the maximum possible length of an instruction, 60 /// which is needed to compute the size of an inline asm. 61 unsigned MaxInstLength; // Defaults to 4. 62 63 /// PCSymbol - The symbol used to represent the current PC. Used in PC 64 /// relative expressions. 65 const char *PCSymbol; // Defaults to "$". 66 67 /// SeparatorChar - This character, if specified, is used to separate 68 /// instructions from each other when on the same line. This is used to 69 /// measure inline asm instructions. 70 char SeparatorChar; // Defaults to ';' 71 72 /// CommentColumn - This indicates the comment num (zero-based) at 73 /// which asm comments should be printed. 74 unsigned CommentColumn; // Defaults to 40 75 76 /// CommentString - This indicates the comment character used by the 77 /// assembler. 78 const char *CommentString; // Defaults to "#" 79 80 /// LabelSuffix - This is appended to emitted labels. 81 const char *LabelSuffix; // Defaults to ":" 82 83 /// GlobalPrefix - If this is set to a non-empty string, it is prepended 84 /// onto all global symbols. This is often used for "_" or ".". 85 const char *GlobalPrefix; // Defaults to "" 86 87 /// PrivateGlobalPrefix - This prefix is used for globals like constant 88 /// pool entries that are completely private to the .s file and should not 89 /// have names in the .o file. This is often "." or "L". 90 const char *PrivateGlobalPrefix; // Defaults to "." 91 92 /// LinkerPrivateGlobalPrefix - This prefix is used for symbols that should 93 /// be passed through the assembler but be removed by the linker. This 94 /// is "l" on Darwin, currently used for some ObjC metadata. 95 const char *LinkerPrivateGlobalPrefix; // Defaults to "" 96 97 /// InlineAsmStart/End - If these are nonempty, they contain a directive to 98 /// emit before and after an inline assembly statement. 99 const char *InlineAsmStart; // Defaults to "#APP\n" 100 const char *InlineAsmEnd; // Defaults to "#NO_APP\n" 101 102 /// AssemblerDialect - Which dialect of an assembler variant to use. 103 unsigned AssemblerDialect; // Defaults to 0 104 105 /// AllowQuotesInName - This is true if the assembler allows for complex 106 /// symbol names to be surrounded in quotes. This defaults to false. 107 bool AllowQuotesInName; 108 109 /// AllowNameToStartWithDigit - This is true if the assembler allows symbol 110 /// names to start with a digit (e.g., "0x0021"). This defaults to false. 111 bool AllowNameToStartWithDigit; 112 113 /// AllowPeriodsInName - This is true if the assembler allows periods in 114 /// symbol names. This defaults to true. 115 bool AllowPeriodsInName; 116 117 //===--- Data Emission Directives -------------------------------------===// 118 119 /// ZeroDirective - this should be set to the directive used to get some 120 /// number of zero bytes emitted to the current section. Common cases are 121 /// "\t.zero\t" and "\t.space\t". If this is set to null, the 122 /// Data*bitsDirective's will be used to emit zero bytes. 123 const char *ZeroDirective; // Defaults to "\t.zero\t" 124 125 /// AsciiDirective - This directive allows emission of an ascii string with 126 /// the standard C escape characters embedded into it. 127 const char *AsciiDirective; // Defaults to "\t.ascii\t" 128 129 /// AscizDirective - If not null, this allows for special handling of 130 /// zero terminated strings on this target. This is commonly supported as 131 /// ".asciz". If a target doesn't support this, it can be set to null. 132 const char *AscizDirective; // Defaults to "\t.asciz\t" 133 134 /// DataDirectives - These directives are used to output some unit of 135 /// integer data to the current section. If a data directive is set to 136 /// null, smaller data directives will be used to emit the large sizes. 137 const char *Data8bitsDirective; // Defaults to "\t.byte\t" 138 const char *Data16bitsDirective; // Defaults to "\t.short\t" 139 const char *Data32bitsDirective; // Defaults to "\t.long\t" 140 const char *Data64bitsDirective; // Defaults to "\t.quad\t" 141 142 /// GPRel32Directive - if non-null, a directive that is used to emit a word 143 /// which should be relocated as a 32-bit GP-relative offset, e.g. .gpword 144 /// on Mips or .gprel32 on Alpha. 145 const char *GPRel32Directive; // Defaults to NULL. 146 147 /// getDataASDirective - Return the directive that should be used to emit 148 /// data of the specified size to the specified numeric address space. 149 virtual const char *getDataASDirective(unsigned Size, unsigned AS) const { 150 assert(AS != 0 && "Don't know the directives for default addr space"); 151 return 0; 152 } 153 154 /// SunStyleELFSectionSwitchSyntax - This is true if this target uses "Sun 155 /// Style" syntax for section switching ("#alloc,#write" etc) instead of the 156 /// normal ELF syntax (,"a,w") in .section directives. 157 bool SunStyleELFSectionSwitchSyntax; // Defaults to false. 158 159 /// UsesELFSectionDirectiveForBSS - This is true if this target uses ELF 160 /// '.section' directive before the '.bss' one. It's used for PPC/Linux 161 /// which doesn't support the '.bss' directive only. 162 bool UsesELFSectionDirectiveForBSS; // Defaults to false. 163 164 /// HasMicrosoftFastStdCallMangling - True if this target uses microsoft 165 /// style mangling for functions with X86_StdCall/X86_FastCall calling 166 /// convention. 167 bool HasMicrosoftFastStdCallMangling; // Defaults to false. 168 169 //===--- Alignment Information ----------------------------------------===// 170 171 /// AlignDirective - The directive used to emit round up to an alignment 172 /// boundary. 173 /// 174 const char *AlignDirective; // Defaults to "\t.align\t" 175 176 /// AlignmentIsInBytes - If this is true (the default) then the asmprinter 177 /// emits ".align N" directives, where N is the number of bytes to align to. 178 /// Otherwise, it emits ".align log2(N)", e.g. 3 to align to an 8 byte 179 /// boundary. 180 bool AlignmentIsInBytes; // Defaults to true 181 182 /// TextAlignFillValue - If non-zero, this is used to fill the executable 183 /// space created as the result of a alignment directive. 184 unsigned TextAlignFillValue; // Defaults to 0 185 186 //===--- Global Variable Emission Directives --------------------------===// 187 188 /// GlobalDirective - This is the directive used to declare a global entity. 189 /// 190 const char *GlobalDirective; // Defaults to NULL. 191 192 /// ExternDirective - This is the directive used to declare external 193 /// globals. 194 /// 195 const char *ExternDirective; // Defaults to NULL. 196 197 /// HasSetDirective - True if the assembler supports the .set directive. 198 bool HasSetDirective; // Defaults to true. 199 200 /// HasLCOMMDirective - This is true if the target supports the .lcomm 201 /// directive. 202 bool HasLCOMMDirective; // Defaults to false. 203 204 /// COMMDirectiveAlignmentIsInBytes - True is COMMDirective's optional 205 /// alignment is to be specified in bytes instead of log2(n). 206 bool COMMDirectiveAlignmentIsInBytes; // Defaults to true; 207 208 /// HasDotTypeDotSizeDirective - True if the target has .type and .size 209 /// directives, this is true for most ELF targets. 210 bool HasDotTypeDotSizeDirective; // Defaults to true. 211 212 /// HasSingleParameterDotFile - True if the target has a single parameter 213 /// .file directive, this is true for ELF targets. 214 bool HasSingleParameterDotFile; // Defaults to true. 215 216 /// HasNoDeadStrip - True if this target supports the MachO .no_dead_strip 217 /// directive. 218 bool HasNoDeadStrip; // Defaults to false. 219 220 /// HasSymbolResolver - True if this target supports the MachO 221 /// .symbol_resolver directive. 222 bool HasSymbolResolver; // Defaults to false. 223 224 /// WeakRefDirective - This directive, if non-null, is used to declare a 225 /// global as being a weak undefined symbol. 226 const char *WeakRefDirective; // Defaults to NULL. 227 228 /// WeakDefDirective - This directive, if non-null, is used to declare a 229 /// global as being a weak defined symbol. 230 const char *WeakDefDirective; // Defaults to NULL. 231 232 /// LinkOnceDirective - This directive, if non-null is used to declare a 233 /// global as being a weak defined symbol. This is used on cygwin/mingw. 234 const char *LinkOnceDirective; // Defaults to NULL. 235 236 /// HiddenVisibilityAttr - This attribute, if not MCSA_Invalid, is used to 237 /// declare a symbol as having hidden visibility. 238 MCSymbolAttr HiddenVisibilityAttr; // Defaults to MCSA_Hidden. 239 240 /// ProtectedVisibilityAttr - This attribute, if not MCSA_Invalid, is used 241 /// to declare a symbol as having protected visibility. 242 MCSymbolAttr ProtectedVisibilityAttr; // Defaults to MCSA_Protected 243 244 //===--- Dwarf Emission Directives -----------------------------------===// 245 246 /// HasLEB128 - True if target asm supports leb128 directives. 247 bool HasLEB128; // Defaults to false. 248 249 /// SupportsDebugInformation - True if target supports emission of debugging 250 /// information. 251 bool SupportsDebugInformation; // Defaults to false. 252 253 /// SupportsExceptionHandling - True if target supports exception handling. 254 ExceptionHandling::ExceptionsType ExceptionsType; // Defaults to None 255 256 /// RequiresFrameSection - true if the Dwarf2 output needs a frame section 257 bool DwarfRequiresFrameSection; // Defaults to true. 258 259 /// DwarfUsesInlineInfoSection - True if DwarfDebugInlineSection is used to 260 /// encode inline subroutine information. 261 bool DwarfUsesInlineInfoSection; // Defaults to false. 262 263 /// DwarfSectionOffsetDirective - Special section offset directive. 264 const char* DwarfSectionOffsetDirective; // Defaults to NULL 265 266 /// DwarfUsesAbsoluteLabelForStmtList - True if DW_AT_stmt_list needs 267 /// absolute label instead of offset. 268 bool DwarfUsesAbsoluteLabelForStmtList; // Defaults to true; 269 270 // DwarfUsesLabelOffsetDifference - True if Dwarf2 output can 271 // use EmitLabelOffsetDifference. 272 bool DwarfUsesLabelOffsetForRanges; 273 274 //===--- CBE Asm Translation Table -----------------------------------===// 275 276 const char *const *AsmTransCBE; // Defaults to empty 277 278 public: 279 explicit MCAsmInfo(); 280 virtual ~MCAsmInfo(); 281 282 // FIXME: move these methods to DwarfPrinter when the JIT stops using them. 283 static unsigned getSLEB128Size(int Value); 284 static unsigned getULEB128Size(unsigned Value); 285 286 bool hasSubsectionsViaSymbols() const { return HasSubsectionsViaSymbols; } 287 288 // Data directive accessors. 289 // 290 const char *getData8bitsDirective(unsigned AS = 0) const { 291 return AS == 0 ? Data8bitsDirective : getDataASDirective(8, AS); 292 } 293 const char *getData16bitsDirective(unsigned AS = 0) const { 294 return AS == 0 ? Data16bitsDirective : getDataASDirective(16, AS); 295 } 296 const char *getData32bitsDirective(unsigned AS = 0) const { 297 return AS == 0 ? Data32bitsDirective : getDataASDirective(32, AS); 298 } 299 const char *getData64bitsDirective(unsigned AS = 0) const { 300 return AS == 0 ? Data64bitsDirective : getDataASDirective(64, AS); 301 } 302 const char *getGPRel32Directive() const { return GPRel32Directive; } 303 304 /// getNonexecutableStackSection - Targets can implement this method to 305 /// specify a section to switch to if the translation unit doesn't have any 306 /// trampolines that require an executable stack. 307 virtual const MCSection *getNonexecutableStackSection(MCContext &Ctx) const{ 308 return 0; 309 } 310 311 bool usesSunStyleELFSectionSwitchSyntax() const { 312 return SunStyleELFSectionSwitchSyntax; 313 } 314 315 bool usesELFSectionDirectiveForBSS() const { 316 return UsesELFSectionDirectiveForBSS; 317 } 318 319 bool hasMicrosoftFastStdCallMangling() const { 320 return HasMicrosoftFastStdCallMangling; 321 } 322 323 // Accessors. 324 // 325 bool hasMachoZeroFillDirective() const { return HasMachoZeroFillDirective; } 326 bool hasMachoTBSSDirective() const { return HasMachoTBSSDirective; } 327 bool hasStaticCtorDtorReferenceInStaticMode() const { 328 return HasStaticCtorDtorReferenceInStaticMode; 329 } 330 bool getLinkerRequiresNonEmptyDwarfLines() const { 331 return LinkerRequiresNonEmptyDwarfLines; 332 } 333 unsigned getMaxInstLength() const { 334 return MaxInstLength; 335 } 336 const char *getPCSymbol() const { 337 return PCSymbol; 338 } 339 char getSeparatorChar() const { 340 return SeparatorChar; 341 } 342 unsigned getCommentColumn() const { 343 return CommentColumn; 344 } 345 const char *getCommentString() const { 346 return CommentString; 347 } 348 const char *getLabelSuffix() const { 349 return LabelSuffix; 350 } 351 const char *getGlobalPrefix() const { 352 return GlobalPrefix; 353 } 354 const char *getPrivateGlobalPrefix() const { 355 return PrivateGlobalPrefix; 356 } 357 const char *getLinkerPrivateGlobalPrefix() const { 358 return LinkerPrivateGlobalPrefix; 359 } 360 const char *getInlineAsmStart() const { 361 return InlineAsmStart; 362 } 363 const char *getInlineAsmEnd() const { 364 return InlineAsmEnd; 365 } 366 unsigned getAssemblerDialect() const { 367 return AssemblerDialect; 368 } 369 bool doesAllowQuotesInName() const { 370 return AllowQuotesInName; 371 } 372 bool doesAllowNameToStartWithDigit() const { 373 return AllowNameToStartWithDigit; 374 } 375 bool doesAllowPeriodsInName() const { 376 return AllowPeriodsInName; 377 } 378 const char *getZeroDirective() const { 379 return ZeroDirective; 380 } 381 const char *getAsciiDirective() const { 382 return AsciiDirective; 383 } 384 const char *getAscizDirective() const { 385 return AscizDirective; 386 } 387 const char *getAlignDirective() const { 388 return AlignDirective; 389 } 390 bool getAlignmentIsInBytes() const { 391 return AlignmentIsInBytes; 392 } 393 unsigned getTextAlignFillValue() const { 394 return TextAlignFillValue; 395 } 396 const char *getGlobalDirective() const { 397 return GlobalDirective; 398 } 399 const char *getExternDirective() const { 400 return ExternDirective; 401 } 402 bool hasSetDirective() const { return HasSetDirective; } 403 bool hasLCOMMDirective() const { return HasLCOMMDirective; } 404 bool hasDotTypeDotSizeDirective() const {return HasDotTypeDotSizeDirective;} 405 bool getCOMMDirectiveAlignmentIsInBytes() const { 406 return COMMDirectiveAlignmentIsInBytes; 407 } 408 bool hasSingleParameterDotFile() const { return HasSingleParameterDotFile; } 409 bool hasNoDeadStrip() const { return HasNoDeadStrip; } 410 bool hasSymbolResolver() const { return HasSymbolResolver; } 411 const char *getWeakRefDirective() const { return WeakRefDirective; } 412 const char *getWeakDefDirective() const { return WeakDefDirective; } 413 const char *getLinkOnceDirective() const { return LinkOnceDirective; } 414 415 MCSymbolAttr getHiddenVisibilityAttr() const { return HiddenVisibilityAttr;} 416 MCSymbolAttr getProtectedVisibilityAttr() const { 417 return ProtectedVisibilityAttr; 418 } 419 bool hasLEB128() const { 420 return HasLEB128; 421 } 422 bool doesSupportDebugInformation() const { 423 return SupportsDebugInformation; 424 } 425 bool doesSupportExceptionHandling() const { 426 return ExceptionsType != ExceptionHandling::None; 427 } 428 ExceptionHandling::ExceptionsType getExceptionHandlingType() const { 429 return ExceptionsType; 430 } 431 bool doesDwarfRequireFrameSection() const { 432 return DwarfRequiresFrameSection; 433 } 434 bool doesDwarfUsesInlineInfoSection() const { 435 return DwarfUsesInlineInfoSection; 436 } 437 const char *getDwarfSectionOffsetDirective() const { 438 return DwarfSectionOffsetDirective; 439 } 440 bool doesDwarfUsesAbsoluteLabelForStmtList() const { 441 return DwarfUsesAbsoluteLabelForStmtList; 442 } 443 bool doesDwarfUsesLabelOffsetForRanges() const { 444 return DwarfUsesLabelOffsetForRanges; 445 } 446 const char *const *getAsmCBE() const { 447 return AsmTransCBE; 448 } 449 }; 450} 451 452#endif 453