MCAsmInfo.h revision 09d53fecfcc93377627b6ee7b4d92f8a6ff152e9
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 /// HasStaticCtorDtorReferenceInStaticMode - True if the compiler should 45 /// emit a ".reference .constructors_used" or ".reference .destructors_used" 46 /// directive after the a static ctor/dtor list. This directive is only 47 /// emitted in Static relocation model. 48 bool HasStaticCtorDtorReferenceInStaticMode; // Default is false. 49 50 /// MaxInstLength - This is the maximum possible length of an instruction, 51 /// which is needed to compute the size of an inline asm. 52 unsigned MaxInstLength; // Defaults to 4. 53 54 /// PCSymbol - The symbol used to represent the current PC. Used in PC 55 /// relative expressions. 56 const char *PCSymbol; // Defaults to "$". 57 58 /// SeparatorChar - This character, if specified, is used to separate 59 /// instructions from each other when on the same line. This is used to 60 /// measure inline asm instructions. 61 char SeparatorChar; // Defaults to ';' 62 63 /// CommentColumn - This indicates the comment num (zero-based) at 64 /// which asm comments should be printed. 65 unsigned CommentColumn; // Defaults to 40 66 67 /// CommentString - This indicates the comment character used by the 68 /// assembler. 69 const char *CommentString; // Defaults to "#" 70 71 /// GlobalPrefix - If this is set to a non-empty string, it is prepended 72 /// onto all global symbols. This is often used for "_" or ".". 73 const char *GlobalPrefix; // Defaults to "" 74 75 /// PrivateGlobalPrefix - This prefix is used for globals like constant 76 /// pool entries that are completely private to the .s file and should not 77 /// have names in the .o file. This is often "." or "L". 78 const char *PrivateGlobalPrefix; // Defaults to "." 79 80 /// LinkerPrivateGlobalPrefix - This prefix is used for symbols that should 81 /// be passed through the assembler but be removed by the linker. This 82 /// is "l" on Darwin, currently used for some ObjC metadata. 83 const char *LinkerPrivateGlobalPrefix; // Defaults to "" 84 85 /// InlineAsmStart/End - If these are nonempty, they contain a directive to 86 /// emit before and after an inline assembly statement. 87 const char *InlineAsmStart; // Defaults to "#APP\n" 88 const char *InlineAsmEnd; // Defaults to "#NO_APP\n" 89 90 /// AssemblerDialect - Which dialect of an assembler variant to use. 91 unsigned AssemblerDialect; // Defaults to 0 92 93 /// AllowQuotesInName - This is true if the assembler allows for complex 94 /// symbol names to be surrounded in quotes. This defaults to false. 95 bool AllowQuotesInName; 96 97 /// AllowNameToStartWithDigit - This is true if the assembler allows symbol 98 /// names to start with a digit (e.g., "0x0021"). This defaults to false. 99 bool AllowNameToStartWithDigit; 100 101 //===--- Data Emission Directives -------------------------------------===// 102 103 /// ZeroDirective - this should be set to the directive used to get some 104 /// number of zero bytes emitted to the current section. Common cases are 105 /// "\t.zero\t" and "\t.space\t". If this is set to null, the 106 /// Data*bitsDirective's will be used to emit zero bytes. 107 const char *ZeroDirective; // Defaults to "\t.zero\t" 108 109 /// AsciiDirective - This directive allows emission of an ascii string with 110 /// the standard C escape characters embedded into it. 111 const char *AsciiDirective; // Defaults to "\t.ascii\t" 112 113 /// AscizDirective - If not null, this allows for special handling of 114 /// zero terminated strings on this target. This is commonly supported as 115 /// ".asciz". If a target doesn't support this, it can be set to null. 116 const char *AscizDirective; // Defaults to "\t.asciz\t" 117 118 /// DataDirectives - These directives are used to output some unit of 119 /// integer data to the current section. If a data directive is set to 120 /// null, smaller data directives will be used to emit the large sizes. 121 const char *Data8bitsDirective; // Defaults to "\t.byte\t" 122 const char *Data16bitsDirective; // Defaults to "\t.short\t" 123 const char *Data32bitsDirective; // Defaults to "\t.long\t" 124 const char *Data64bitsDirective; // Defaults to "\t.quad\t" 125 126 /// GPRel32Directive - if non-null, a directive that is used to emit a word 127 /// which should be relocated as a 32-bit GP-relative offset, e.g. .gpword 128 /// on Mips or .gprel32 on Alpha. 129 const char *GPRel32Directive; // Defaults to NULL. 130 131 /// getDataASDirective - Return the directive that should be used to emit 132 /// data of the specified size to the specified numeric address space. 133 virtual const char *getDataASDirective(unsigned Size, unsigned AS) const { 134 assert(AS != 0 && "Don't know the directives for default addr space"); 135 return 0; 136 } 137 138 /// SunStyleELFSectionSwitchSyntax - This is true if this target uses "Sun 139 /// Style" syntax for section switching ("#alloc,#write" etc) instead of the 140 /// normal ELF syntax (,"a,w") in .section directives. 141 bool SunStyleELFSectionSwitchSyntax; // Defaults to false. 142 143 /// UsesELFSectionDirectiveForBSS - This is true if this target uses ELF 144 /// '.section' directive before the '.bss' one. It's used for PPC/Linux 145 /// which doesn't support the '.bss' directive only. 146 bool UsesELFSectionDirectiveForBSS; // Defaults to false. 147 148 //===--- Alignment Information ----------------------------------------===// 149 150 /// AlignDirective - The directive used to emit round up to an alignment 151 /// boundary. 152 /// 153 const char *AlignDirective; // Defaults to "\t.align\t" 154 155 /// AlignmentIsInBytes - If this is true (the default) then the asmprinter 156 /// emits ".align N" directives, where N is the number of bytes to align to. 157 /// Otherwise, it emits ".align log2(N)", e.g. 3 to align to an 8 byte 158 /// boundary. 159 bool AlignmentIsInBytes; // Defaults to true 160 161 /// TextAlignFillValue - If non-zero, this is used to fill the executable 162 /// space created as the result of a alignment directive. 163 unsigned TextAlignFillValue; // Defaults to 0 164 165 //===--- Global Variable Emission Directives --------------------------===// 166 167 /// GlobalDirective - This is the directive used to declare a global entity. 168 /// 169 const char *GlobalDirective; // Defaults to NULL. 170 171 /// ExternDirective - This is the directive used to declare external 172 /// globals. 173 /// 174 const char *ExternDirective; // Defaults to NULL. 175 176 /// HasSetDirective - True if the assembler supports the .set directive. 177 bool HasSetDirective; // Defaults to true. 178 179 /// HasLCOMMDirective - This is true if the target supports the .lcomm 180 /// directive. 181 bool HasLCOMMDirective; // Defaults to false. 182 183 /// COMMDirectiveAlignmentIsInBytes - True is COMMDirective's optional 184 /// alignment is to be specified in bytes instead of log2(n). 185 bool COMMDirectiveAlignmentIsInBytes; // Defaults to true; 186 187 /// HasDotTypeDotSizeDirective - True if the target has .type and .size 188 /// directives, this is true for most ELF targets. 189 bool HasDotTypeDotSizeDirective; // Defaults to true. 190 191 /// HasSingleParameterDotFile - True if the target has a single parameter 192 /// .file directive, this is true for ELF targets. 193 bool HasSingleParameterDotFile; // Defaults to true. 194 195 /// HasNoDeadStrip - True if this target supports the MachO .no_dead_strip 196 /// directive. 197 bool HasNoDeadStrip; // Defaults to false. 198 199 /// WeakRefDirective - This directive, if non-null, is used to declare a 200 /// global as being a weak undefined symbol. 201 const char *WeakRefDirective; // Defaults to NULL. 202 203 /// WeakDefDirective - This directive, if non-null, is used to declare a 204 /// global as being a weak defined symbol. 205 const char *WeakDefDirective; // Defaults to NULL. 206 207 /// LinkOnceDirective - This directive, if non-null is used to declare a 208 /// global as being a weak defined symbol. This is used on cygwin/mingw. 209 const char *LinkOnceDirective; // Defaults to NULL. 210 211 /// HiddenVisibilityAttr - This attribute, if not MCSA_Invalid, is used to 212 /// declare a symbol as having hidden visibility. 213 MCSymbolAttr HiddenVisibilityAttr; // Defaults to MCSA_Hidden. 214 215 /// ProtectedVisibilityAttr - This attribute, if not MCSA_Invalid, is used 216 /// to declare a symbol as having protected visibility. 217 MCSymbolAttr ProtectedVisibilityAttr; // Defaults to MCSA_Protected 218 219 //===--- Dwarf Emission Directives -----------------------------------===// 220 221 /// AbsoluteDebugSectionOffsets - True if we should emit abolute section 222 /// offsets for debug information. 223 bool AbsoluteDebugSectionOffsets; // Defaults to false. 224 225 /// AbsoluteEHSectionOffsets - True if we should emit abolute section 226 /// offsets for EH information. Defaults to false. 227 bool AbsoluteEHSectionOffsets; 228 229 /// HasLEB128 - True if target asm supports leb128 directives. 230 bool HasLEB128; // Defaults to false. 231 232 /// hasDotLocAndDotFile - True if target asm supports .loc and .file 233 /// directives for emitting debugging information. 234 bool HasDotLocAndDotFile; // Defaults to false. 235 236 /// SupportsDebugInformation - True if target supports emission of debugging 237 /// information. 238 bool SupportsDebugInformation; // Defaults to false. 239 240 /// SupportsExceptionHandling - True if target supports exception handling. 241 ExceptionHandling::ExceptionsType ExceptionsType; // Defaults to None 242 243 /// RequiresFrameSection - true if the Dwarf2 output needs a frame section 244 bool DwarfRequiresFrameSection; // Defaults to true. 245 246 /// DwarfUsesInlineInfoSection - True if DwarfDebugInlineSection is used to 247 /// encode inline subroutine information. 248 bool DwarfUsesInlineInfoSection; // Defaults to false. 249 250 /// DwarfSectionOffsetDirective - Special section offset directive. 251 const char* DwarfSectionOffsetDirective; // Defaults to NULL 252 253 //===--- CBE Asm Translation Table -----------------------------------===// 254 255 const char *const *AsmTransCBE; // Defaults to empty 256 257 public: 258 explicit MCAsmInfo(); 259 virtual ~MCAsmInfo(); 260 261 // FIXME: move these methods to DwarfPrinter when the JIT stops using them. 262 static unsigned getSLEB128Size(int Value); 263 static unsigned getULEB128Size(unsigned Value); 264 265 bool hasSubsectionsViaSymbols() const { return HasSubsectionsViaSymbols; } 266 267 // Data directive accessors. 268 // 269 const char *getData8bitsDirective(unsigned AS = 0) const { 270 return AS == 0 ? Data8bitsDirective : getDataASDirective(8, AS); 271 } 272 const char *getData16bitsDirective(unsigned AS = 0) const { 273 return AS == 0 ? Data16bitsDirective : getDataASDirective(16, AS); 274 } 275 const char *getData32bitsDirective(unsigned AS = 0) const { 276 return AS == 0 ? Data32bitsDirective : getDataASDirective(32, AS); 277 } 278 const char *getData64bitsDirective(unsigned AS = 0) const { 279 return AS == 0 ? Data64bitsDirective : getDataASDirective(64, AS); 280 } 281 const char *getGPRel32Directive() const { return GPRel32Directive; } 282 283 /// getNonexecutableStackSection - Targets can implement this method to 284 /// specify a section to switch to if the translation unit doesn't have any 285 /// trampolines that require an executable stack. 286 virtual MCSection *getNonexecutableStackSection(MCContext &Ctx) const { 287 return 0; 288 } 289 290 bool usesSunStyleELFSectionSwitchSyntax() const { 291 return SunStyleELFSectionSwitchSyntax; 292 } 293 294 bool usesELFSectionDirectiveForBSS() const { 295 return UsesELFSectionDirectiveForBSS; 296 } 297 298 // Accessors. 299 // 300 bool hasMachoZeroFillDirective() const { return HasMachoZeroFillDirective; } 301 bool hasStaticCtorDtorReferenceInStaticMode() const { 302 return HasStaticCtorDtorReferenceInStaticMode; 303 } 304 unsigned getMaxInstLength() const { 305 return MaxInstLength; 306 } 307 const char *getPCSymbol() const { 308 return PCSymbol; 309 } 310 char getSeparatorChar() const { 311 return SeparatorChar; 312 } 313 unsigned getCommentColumn() const { 314 return CommentColumn; 315 } 316 const char *getCommentString() const { 317 return CommentString; 318 } 319 const char *getGlobalPrefix() const { 320 return GlobalPrefix; 321 } 322 const char *getPrivateGlobalPrefix() const { 323 return PrivateGlobalPrefix; 324 } 325 const char *getLinkerPrivateGlobalPrefix() const { 326 return LinkerPrivateGlobalPrefix; 327 } 328 const char *getInlineAsmStart() const { 329 return InlineAsmStart; 330 } 331 const char *getInlineAsmEnd() const { 332 return InlineAsmEnd; 333 } 334 unsigned getAssemblerDialect() const { 335 return AssemblerDialect; 336 } 337 bool doesAllowQuotesInName() const { 338 return AllowQuotesInName; 339 } 340 bool doesAllowNameToStartWithDigit() const { 341 return AllowNameToStartWithDigit; 342 } 343 const char *getZeroDirective() const { 344 return ZeroDirective; 345 } 346 const char *getAsciiDirective() const { 347 return AsciiDirective; 348 } 349 const char *getAscizDirective() const { 350 return AscizDirective; 351 } 352 const char *getAlignDirective() const { 353 return AlignDirective; 354 } 355 bool getAlignmentIsInBytes() const { 356 return AlignmentIsInBytes; 357 } 358 unsigned getTextAlignFillValue() const { 359 return TextAlignFillValue; 360 } 361 const char *getGlobalDirective() const { 362 return GlobalDirective; 363 } 364 const char *getExternDirective() const { 365 return ExternDirective; 366 } 367 bool hasSetDirective() const { return HasSetDirective; } 368 bool hasLCOMMDirective() const { return HasLCOMMDirective; } 369 bool hasDotTypeDotSizeDirective() const {return HasDotTypeDotSizeDirective;} 370 bool getCOMMDirectiveAlignmentIsInBytes() const { 371 return COMMDirectiveAlignmentIsInBytes; 372 } 373 bool hasSingleParameterDotFile() const { return HasSingleParameterDotFile; } 374 bool hasNoDeadStrip() const { return HasNoDeadStrip; } 375 const char *getWeakRefDirective() const { return WeakRefDirective; } 376 const char *getWeakDefDirective() const { return WeakDefDirective; } 377 const char *getLinkOnceDirective() const { return LinkOnceDirective; } 378 379 MCSymbolAttr getHiddenVisibilityAttr() const { return HiddenVisibilityAttr;} 380 MCSymbolAttr getProtectedVisibilityAttr() const { 381 return ProtectedVisibilityAttr; 382 } 383 bool isAbsoluteDebugSectionOffsets() const { 384 return AbsoluteDebugSectionOffsets; 385 } 386 bool isAbsoluteEHSectionOffsets() const { 387 return AbsoluteEHSectionOffsets; 388 } 389 bool hasLEB128() const { 390 return HasLEB128; 391 } 392 bool hasDotLocAndDotFile() const { 393 return HasDotLocAndDotFile; 394 } 395 bool doesSupportDebugInformation() const { 396 return SupportsDebugInformation; 397 } 398 bool doesSupportExceptionHandling() const { 399 return ExceptionsType != ExceptionHandling::None; 400 } 401 ExceptionHandling::ExceptionsType getExceptionHandlingType() const { 402 return ExceptionsType; 403 } 404 bool doesDwarfRequireFrameSection() const { 405 return DwarfRequiresFrameSection; 406 } 407 bool doesDwarfUsesInlineInfoSection() const { 408 return DwarfUsesInlineInfoSection; 409 } 410 const char *getDwarfSectionOffsetDirective() const { 411 return DwarfSectionOffsetDirective; 412 } 413 const char *const *getAsmCBE() const { 414 return AsmTransCBE; 415 } 416 }; 417} 418 419#endif 420