MCAsmInfo.h revision aac138e84dee1cb3ffc1035b2a1e4361fe0b4f80
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 <cassert> 20 21namespace llvm { 22 /// MCAsmInfo - This class is intended to be used as a base class for asm 23 /// properties and features specific to the target. 24 namespace ExceptionHandling { enum ExceptionsType { None, Dwarf, SjLj }; } 25 26 class MCAsmInfo { 27 protected: 28 //===------------------------------------------------------------------===// 29 // Properties to be set by the target writer, used to configure asm printer. 30 // 31 32 /// NonexecutableStackDirective - Directive for declaring to the 33 /// linker and beyond that the emitted code does not require stack 34 /// memory to be executable. 35 const char *NonexecutableStackDirective; // Default is null. 36 37 /// HasMachoZeroFillDirective - True if this is a MachO target that supports 38 /// the macho-specific .zerofill directive for emitting BSS Symbols. 39 bool HasMachoZeroFillDirective; // Default is false. 40 41 /// NeedsSet - True if target asm treats expressions in data directives 42 /// as linktime-relocatable. For assembly-time computation, we need to 43 /// use a .set. Thus: 44 /// .set w, x-y 45 /// .long w 46 /// is computed at assembly time, while 47 /// .long x-y 48 /// is relocated if the relative locations of x and y change at linktime. 49 /// We want both these things in different places. 50 bool NeedsSet; // Defaults to false. 51 52 /// MaxInstLength - This is the maximum possible length of an instruction, 53 /// which is needed to compute the size of an inline asm. 54 unsigned MaxInstLength; // Defaults to 4. 55 56 /// PCSymbol - The symbol used to represent the current PC. Used in PC 57 /// relative expressions. 58 const char *PCSymbol; // Defaults to "$". 59 60 /// SeparatorChar - This character, if specified, is used to separate 61 /// instructions from each other when on the same line. This is used to 62 /// measure inline asm instructions. 63 char SeparatorChar; // Defaults to ';' 64 65 /// CommentColumn - This indicates the comment num (zero-based) at 66 /// which asm comments should be printed. 67 unsigned CommentColumn; // Defaults to 60 68 69 /// CommentString - This indicates the comment character used by the 70 /// assembler. 71 const char *CommentString; // Defaults to "#" 72 73 /// GlobalPrefix - If this is set to a non-empty string, it is prepended 74 /// onto all global symbols. This is often used for "_" or ".". 75 const char *GlobalPrefix; // Defaults to "" 76 77 /// PrivateGlobalPrefix - This prefix is used for globals like constant 78 /// pool entries that are completely private to the .s file and should not 79 /// have names in the .o file. This is often "." or "L". 80 const char *PrivateGlobalPrefix; // Defaults to "." 81 82 /// LinkerPrivateGlobalPrefix - This prefix is used for symbols that should 83 /// be passed through the assembler but be removed by the linker. This 84 /// is "l" on Darwin, currently used for some ObjC metadata. 85 const char *LinkerPrivateGlobalPrefix; // Defaults to "" 86 87 /// InlineAsmStart/End - If these are nonempty, they contain a directive to 88 /// emit before and after an inline assembly statement. 89 const char *InlineAsmStart; // Defaults to "#APP\n" 90 const char *InlineAsmEnd; // Defaults to "#NO_APP\n" 91 92 /// AssemblerDialect - Which dialect of an assembler variant to use. 93 unsigned AssemblerDialect; // Defaults to 0 94 95 /// AllowQuotesInName - This is true if the assembler allows for complex 96 /// symbol names to be surrounded in quotes. This defaults to false. 97 bool AllowQuotesInName; 98 99 /// AllowNameToStartWithDigit - This is true if the assembler allows symbol 100 /// names to start with a digit (e.g., "0x0021"). This defaults to false. 101 bool AllowNameToStartWithDigit; 102 103 //===--- Data Emission Directives -------------------------------------===// 104 105 /// ZeroDirective - this should be set to the directive used to get some 106 /// number of zero bytes emitted to the current section. Common cases are 107 /// "\t.zero\t" and "\t.space\t". If this is set to null, the 108 /// Data*bitsDirective's will be used to emit zero bytes. 109 const char *ZeroDirective; // Defaults to "\t.zero\t" 110 const char *ZeroDirectiveSuffix; // Defaults to "" 111 112 /// AsciiDirective - This directive allows emission of an ascii string with 113 /// the standard C escape characters embedded into it. 114 const char *AsciiDirective; // Defaults to "\t.ascii\t" 115 116 /// AscizDirective - If not null, this allows for special handling of 117 /// zero terminated strings on this target. This is commonly supported as 118 /// ".asciz". If a target doesn't support this, it can be set to null. 119 const char *AscizDirective; // Defaults to "\t.asciz\t" 120 121 /// DataDirectives - These directives are used to output some unit of 122 /// integer data to the current section. If a data directive is set to 123 /// null, smaller data directives will be used to emit the large sizes. 124 const char *Data8bitsDirective; // Defaults to "\t.byte\t" 125 const char *Data16bitsDirective; // Defaults to "\t.short\t" 126 const char *Data32bitsDirective; // Defaults to "\t.long\t" 127 const char *Data64bitsDirective; // Defaults to "\t.quad\t" 128 129 /// getDataASDirective - Return the directive that should be used to emit 130 /// data of the specified size to the specified numeric address space. 131 virtual const char *getDataASDirective(unsigned Size, unsigned AS) const { 132 assert(AS != 0 && "Don't know the directives for default addr space"); 133 return 0; 134 } 135 136 /// SunStyleELFSectionSwitchSyntax - This is true if this target uses "Sun 137 /// Style" syntax for section switching ("#alloc,#write" etc) instead of the 138 /// normal ELF syntax (,"a,w") in .section directives. 139 bool SunStyleELFSectionSwitchSyntax; // Defaults to false. 140 141 /// UsesELFSectionDirectiveForBSS - This is true if this target uses ELF 142 /// '.section' directive before the '.bss' one. It's used for PPC/Linux 143 /// which doesn't support the '.bss' directive only. 144 bool UsesELFSectionDirectiveForBSS; // Defaults to false. 145 146 //===--- Alignment Information ----------------------------------------===// 147 148 /// AlignDirective - The directive used to emit round up to an alignment 149 /// boundary. 150 /// 151 const char *AlignDirective; // Defaults to "\t.align\t" 152 153 /// AlignmentIsInBytes - If this is true (the default) then the asmprinter 154 /// emits ".align N" directives, where N is the number of bytes to align to. 155 /// Otherwise, it emits ".align log2(N)", e.g. 3 to align to an 8 byte 156 /// boundary. 157 bool AlignmentIsInBytes; // Defaults to true 158 159 /// TextAlignFillValue - If non-zero, this is used to fill the executable 160 /// space created as the result of a alignment directive. 161 unsigned TextAlignFillValue; // Defaults to 0 162 163 //===--- Section Switching Directives ---------------------------------===// 164 165 /// JumpTableDirective - if non-null, the directive to emit before jump 166 /// table entries. FIXME: REMOVE THIS. 167 const char *JumpTableDirective; // Defaults to NULL. 168 const char *PICJumpTableDirective; // Defaults to NULL. 169 170 171 //===--- Global Variable Emission Directives --------------------------===// 172 173 /// GlobalDirective - This is the directive used to declare a global entity. 174 /// 175 const char *GlobalDirective; // Defaults to NULL. 176 177 /// ExternDirective - This is the directive used to declare external 178 /// globals. 179 /// 180 const char *ExternDirective; // Defaults to NULL. 181 182 /// SetDirective - This is the name of a directive that can be used to tell 183 /// the assembler to set the value of a variable to some expression. 184 const char *SetDirective; // Defaults to null. 185 186 /// LCOMMDirective - This is the name of a directive (if supported) that can 187 /// be used to efficiently declare a local (internal) block of zero 188 /// initialized data in the .bss/.data section. The syntax expected is: 189 /// @verbatim <LCOMMDirective> SYMBOLNAME LENGTHINBYTES, ALIGNMENT 190 /// @endverbatim 191 const char *LCOMMDirective; // Defaults to null. 192 193 const char *COMMDirective; // Defaults to "\t.comm\t". 194 195 /// COMMDirectiveTakesAlignment - True if COMMDirective take a third 196 /// argument that specifies the alignment of the declaration. 197 bool COMMDirectiveTakesAlignment; // Defaults to true. 198 199 /// HasDotTypeDotSizeDirective - True if the target has .type and .size 200 /// directives, this is true for most ELF targets. 201 bool HasDotTypeDotSizeDirective; // Defaults to true. 202 203 /// HasSingleParameterDotFile - True if the target has a single parameter 204 /// .file directive, this is true for ELF targets. 205 bool HasSingleParameterDotFile; // Defaults to true. 206 207 /// UsedDirective - This directive, if non-null, is used to declare a global 208 /// as being used somehow that the assembler can't see. This prevents dead 209 /// code elimination on some targets. 210 const char *UsedDirective; // Defaults to NULL. 211 212 /// WeakRefDirective - This directive, if non-null, is used to declare a 213 /// global as being a weak undefined symbol. 214 const char *WeakRefDirective; // Defaults to NULL. 215 216 /// WeakDefDirective - This directive, if non-null, is used to declare a 217 /// global as being a weak defined symbol. 218 const char *WeakDefDirective; // Defaults to NULL. 219 220 /// HiddenDirective - This directive, if non-null, is used to declare a 221 /// global or function as having hidden visibility. 222 const char *HiddenDirective; // Defaults to "\t.hidden\t". 223 224 /// ProtectedDirective - This directive, if non-null, is used to declare a 225 /// global or function as having protected visibility. 226 const char *ProtectedDirective; // Defaults to "\t.protected\t". 227 228 //===--- Dwarf Emission Directives -----------------------------------===// 229 230 /// AbsoluteDebugSectionOffsets - True if we should emit abolute section 231 /// offsets for debug information. 232 bool AbsoluteDebugSectionOffsets; // Defaults to false. 233 234 /// AbsoluteEHSectionOffsets - True if we should emit abolute section 235 /// offsets for EH information. Defaults to false. 236 bool AbsoluteEHSectionOffsets; 237 238 /// HasLEB128 - True if target asm supports leb128 directives. 239 bool HasLEB128; // Defaults to false. 240 241 /// hasDotLocAndDotFile - True if target asm supports .loc and .file 242 /// directives for emitting debugging information. 243 bool HasDotLocAndDotFile; // Defaults to false. 244 245 /// SupportsDebugInformation - True if target supports emission of debugging 246 /// information. 247 bool SupportsDebugInformation; // Defaults to false. 248 249 /// SupportsExceptionHandling - True if target supports exception handling. 250 ExceptionHandling::ExceptionsType ExceptionsType; // Defaults to None 251 252 /// RequiresFrameSection - true if the Dwarf2 output needs a frame section 253 bool DwarfRequiresFrameSection; // Defaults to true. 254 255 /// DwarfUsesInlineInfoSection - True if DwarfDebugInlineSection is used to 256 /// encode inline subroutine information. 257 bool DwarfUsesInlineInfoSection; // Defaults to false. 258 259 /// Is_EHSymbolPrivate - If set, the "_foo.eh" is made private so that it 260 /// doesn't show up in the symbol table of the object file. 261 bool Is_EHSymbolPrivate; // Defaults to true. 262 263 /// GlobalEHDirective - This is the directive used to make exception frame 264 /// tables globally visible. 265 const char *GlobalEHDirective; // Defaults to NULL. 266 267 /// SupportsWeakEmptyEHFrame - True if target assembler and linker will 268 /// handle a weak_definition of constant 0 for an omitted EH frame. 269 bool SupportsWeakOmittedEHFrame; // Defaults to true. 270 271 /// DwarfSectionOffsetDirective - Special section offset directive. 272 const char* DwarfSectionOffsetDirective; // Defaults to NULL 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 /// getSLEB128Size - Compute the number of bytes required for a signed 283 /// leb128 value. 284 static unsigned getSLEB128Size(int Value); 285 286 /// getULEB128Size - Compute the number of bytes required for an unsigned 287 /// leb128 value. 288 static unsigned getULEB128Size(unsigned Value); 289 290 // Data directive accessors. 291 // 292 const char *getData8bitsDirective(unsigned AS = 0) const { 293 return AS == 0 ? Data8bitsDirective : getDataASDirective(8, AS); 294 } 295 const char *getData16bitsDirective(unsigned AS = 0) const { 296 return AS == 0 ? Data16bitsDirective : getDataASDirective(16, AS); 297 } 298 const char *getData32bitsDirective(unsigned AS = 0) const { 299 return AS == 0 ? Data32bitsDirective : getDataASDirective(32, AS); 300 } 301 const char *getData64bitsDirective(unsigned AS = 0) const { 302 return AS == 0 ? Data64bitsDirective : getDataASDirective(64, AS); 303 } 304 305 306 bool usesSunStyleELFSectionSwitchSyntax() const { 307 return SunStyleELFSectionSwitchSyntax; 308 } 309 310 bool usesELFSectionDirectiveForBSS() const { 311 return UsesELFSectionDirectiveForBSS; 312 } 313 314 // Accessors. 315 // 316 bool hasMachoZeroFillDirective() const { return HasMachoZeroFillDirective; } 317 318 const char *getNonexecutableStackDirective() const { 319 return NonexecutableStackDirective; 320 } 321 bool needsSet() const { 322 return NeedsSet; 323 } 324 unsigned getMaxInstLength() const { 325 return MaxInstLength; 326 } 327 const char *getPCSymbol() const { 328 return PCSymbol; 329 } 330 char getSeparatorChar() const { 331 return SeparatorChar; 332 } 333 unsigned getCommentColumn() const { 334 return CommentColumn; 335 } 336 const char *getCommentString() const { 337 return CommentString; 338 } 339 const char *getGlobalPrefix() const { 340 return GlobalPrefix; 341 } 342 const char *getPrivateGlobalPrefix() const { 343 return PrivateGlobalPrefix; 344 } 345 const char *getLinkerPrivateGlobalPrefix() const { 346 return LinkerPrivateGlobalPrefix; 347 } 348 const char *getInlineAsmStart() const { 349 return InlineAsmStart; 350 } 351 const char *getInlineAsmEnd() const { 352 return InlineAsmEnd; 353 } 354 unsigned getAssemblerDialect() const { 355 return AssemblerDialect; 356 } 357 bool doesAllowQuotesInName() const { 358 return AllowQuotesInName; 359 } 360 bool doesAllowNameToStartWithDigit() const { 361 return AllowNameToStartWithDigit; 362 } 363 const char *getZeroDirective() const { 364 return ZeroDirective; 365 } 366 const char *getZeroDirectiveSuffix() const { 367 return ZeroDirectiveSuffix; 368 } 369 const char *getAsciiDirective() const { 370 return AsciiDirective; 371 } 372 const char *getAscizDirective() const { 373 return AscizDirective; 374 } 375 const char *getJumpTableDirective(bool isPIC) const { 376 return isPIC ? PICJumpTableDirective : JumpTableDirective; 377 } 378 const char *getAlignDirective() const { 379 return AlignDirective; 380 } 381 bool getAlignmentIsInBytes() const { 382 return AlignmentIsInBytes; 383 } 384 unsigned getTextAlignFillValue() const { 385 return TextAlignFillValue; 386 } 387 const char *getGlobalDirective() const { 388 return GlobalDirective; 389 } 390 const char *getExternDirective() const { 391 return ExternDirective; 392 } 393 const char *getSetDirective() const { 394 return SetDirective; 395 } 396 const char *getLCOMMDirective() const { 397 return LCOMMDirective; 398 } 399 const char *getCOMMDirective() const { 400 return COMMDirective; 401 } 402 bool getCOMMDirectiveTakesAlignment() const { 403 return COMMDirectiveTakesAlignment; 404 } 405 bool hasDotTypeDotSizeDirective() const { 406 return HasDotTypeDotSizeDirective; 407 } 408 bool hasSingleParameterDotFile() const { 409 return HasSingleParameterDotFile; 410 } 411 const char *getUsedDirective() const { 412 return UsedDirective; 413 } 414 const char *getWeakRefDirective() const { 415 return WeakRefDirective; 416 } 417 const char *getWeakDefDirective() const { 418 return WeakDefDirective; 419 } 420 const char *getHiddenDirective() const { 421 return HiddenDirective; 422 } 423 const char *getProtectedDirective() const { 424 return ProtectedDirective; 425 } 426 bool isAbsoluteDebugSectionOffsets() const { 427 return AbsoluteDebugSectionOffsets; 428 } 429 bool isAbsoluteEHSectionOffsets() const { 430 return AbsoluteEHSectionOffsets; 431 } 432 bool hasLEB128() const { 433 return HasLEB128; 434 } 435 bool hasDotLocAndDotFile() const { 436 return HasDotLocAndDotFile; 437 } 438 bool doesSupportDebugInformation() const { 439 return SupportsDebugInformation; 440 } 441 bool doesSupportExceptionHandling() const { 442 return ExceptionsType != ExceptionHandling::None; 443 } 444 ExceptionHandling::ExceptionsType getExceptionHandlingType() const { 445 return ExceptionsType; 446 } 447 bool doesDwarfRequireFrameSection() const { 448 return DwarfRequiresFrameSection; 449 } 450 bool doesDwarfUsesInlineInfoSection() const { 451 return DwarfUsesInlineInfoSection; 452 } 453 bool is_EHSymbolPrivate() const { 454 return Is_EHSymbolPrivate; 455 } 456 const char *getGlobalEHDirective() const { 457 return GlobalEHDirective; 458 } 459 bool getSupportsWeakOmittedEHFrame() const { 460 return SupportsWeakOmittedEHFrame; 461 } 462 const char *getDwarfSectionOffsetDirective() const { 463 return DwarfSectionOffsetDirective; 464 } 465 const char *const *getAsmCBE() const { 466 return AsmTransCBE; 467 } 468 }; 469} 470 471#endif 472