1 //===- MCContext.h - Machine Code Context -----------------------*- 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 #ifndef LLVM_MC_MCCONTEXT_H 11 #define LLVM_MC_MCCONTEXT_H 12 13 #include "llvm/ADT/DenseMap.h" 14 #include "llvm/ADT/SetVector.h" 15 #include "llvm/ADT/SmallString.h" 16 #include "llvm/ADT/SmallVector.h" 17 #include "llvm/ADT/StringMap.h" 18 #include "llvm/ADT/Twine.h" 19 #include "llvm/MC/MCCodeView.h" 20 #include "llvm/MC/MCDwarf.h" 21 #include "llvm/MC/MCSubtargetInfo.h" 22 #include "llvm/MC/SectionKind.h" 23 #include "llvm/Support/Allocator.h" 24 #include "llvm/Support/Compiler.h" 25 #include "llvm/Support/raw_ostream.h" 26 #include <map> 27 #include <tuple> 28 #include <vector> // FIXME: Shouldn't be needed. 29 30 namespace llvm { 31 class MCAsmInfo; 32 class MCExpr; 33 class MCSection; 34 class MCSymbol; 35 class MCSymbolELF; 36 class MCLabel; 37 struct MCDwarfFile; 38 class MCDwarfLoc; 39 class MCObjectFileInfo; 40 class MCRegisterInfo; 41 class MCLineSection; 42 class SMLoc; 43 class MCSectionMachO; 44 class MCSectionELF; 45 class MCSectionCOFF; 46 class CodeViewContext; 47 48 /// Context object for machine code objects. This class owns all of the 49 /// sections that it creates. 50 /// 51 class MCContext { 52 MCContext(const MCContext &) = delete; 53 MCContext &operator=(const MCContext &) = delete; 54 55 public: 56 typedef StringMap<MCSymbol *, BumpPtrAllocator &> SymbolTable; 57 58 private: 59 /// The SourceMgr for this object, if any. 60 const SourceMgr *SrcMgr; 61 62 /// The MCAsmInfo for this target. 63 const MCAsmInfo *MAI; 64 65 /// The MCRegisterInfo for this target. 66 const MCRegisterInfo *MRI; 67 68 /// The MCObjectFileInfo for this target. 69 const MCObjectFileInfo *MOFI; 70 71 std::unique_ptr<CodeViewContext> CVContext; 72 73 /// Allocator object used for creating machine code objects. 74 /// 75 /// We use a bump pointer allocator to avoid the need to track all allocated 76 /// objects. 77 BumpPtrAllocator Allocator; 78 79 SpecificBumpPtrAllocator<MCSectionCOFF> COFFAllocator; 80 SpecificBumpPtrAllocator<MCSectionELF> ELFAllocator; 81 SpecificBumpPtrAllocator<MCSectionMachO> MachOAllocator; 82 83 /// Bindings of names to symbols. 84 SymbolTable Symbols; 85 86 /// ELF sections can have a corresponding symbol. This maps one to the 87 /// other. 88 DenseMap<const MCSectionELF *, MCSymbolELF *> SectionSymbols; 89 90 /// A mapping from a local label number and an instance count to a symbol. 91 /// For example, in the assembly 92 /// 1: 93 /// 2: 94 /// 1: 95 /// We have three labels represented by the pairs (1, 0), (2, 0) and (1, 1) 96 DenseMap<std::pair<unsigned, unsigned>, MCSymbol *> LocalSymbols; 97 98 /// Keeps tracks of names that were used both for used declared and 99 /// artificial symbols. The value is "true" if the name has been used for a 100 /// non-section symbol (there can be at most one of those, plus an unlimited 101 /// number of section symbols with the same name). 102 StringMap<bool, BumpPtrAllocator &> UsedNames; 103 104 /// The next ID to dole out to an unnamed assembler temporary symbol with 105 /// a given prefix. 106 StringMap<unsigned> NextID; 107 108 /// Instances of directional local labels. 109 DenseMap<unsigned, MCLabel *> Instances; 110 /// NextInstance() creates the next instance of the directional local label 111 /// for the LocalLabelVal and adds it to the map if needed. 112 unsigned NextInstance(unsigned LocalLabelVal); 113 /// GetInstance() gets the current instance of the directional local label 114 /// for the LocalLabelVal and adds it to the map if needed. 115 unsigned GetInstance(unsigned LocalLabelVal); 116 117 /// The file name of the log file from the environment variable 118 /// AS_SECURE_LOG_FILE. Which must be set before the .secure_log_unique 119 /// directive is used or it is an error. 120 char *SecureLogFile; 121 /// The stream that gets written to for the .secure_log_unique directive. 122 std::unique_ptr<raw_fd_ostream> SecureLog; 123 /// Boolean toggled when .secure_log_unique / .secure_log_reset is seen to 124 /// catch errors if .secure_log_unique appears twice without 125 /// .secure_log_reset appearing between them. 126 bool SecureLogUsed; 127 128 /// The compilation directory to use for DW_AT_comp_dir. 129 SmallString<128> CompilationDir; 130 131 /// The main file name if passed in explicitly. 132 std::string MainFileName; 133 134 /// The dwarf file and directory tables from the dwarf .file directive. 135 /// We now emit a line table for each compile unit. To reduce the prologue 136 /// size of each line table, the files and directories used by each compile 137 /// unit are separated. 138 std::map<unsigned, MCDwarfLineTable> MCDwarfLineTablesCUMap; 139 140 /// The current dwarf line information from the last dwarf .loc directive. 141 MCDwarfLoc CurrentDwarfLoc; 142 bool DwarfLocSeen; 143 144 /// The current CodeView line information from the last .cv_loc directive. 145 MCCVLoc CurrentCVLoc = MCCVLoc(0, 0, 0, 0, false, true); 146 bool CVLocSeen = false; 147 148 /// Generate dwarf debugging info for assembly source files. 149 bool GenDwarfForAssembly; 150 151 /// The current dwarf file number when generate dwarf debugging info for 152 /// assembly source files. 153 unsigned GenDwarfFileNumber; 154 155 /// Sections for generating the .debug_ranges and .debug_aranges sections. 156 SetVector<MCSection *> SectionsForRanges; 157 158 /// The information gathered from labels that will have dwarf label 159 /// entries when generating dwarf assembly source files. 160 std::vector<MCGenDwarfLabelEntry> MCGenDwarfLabelEntries; 161 162 /// The string to embed in the debug information for the compile unit, if 163 /// non-empty. 164 StringRef DwarfDebugFlags; 165 166 /// The string to embed in as the dwarf AT_producer for the compile unit, if 167 /// non-empty. 168 StringRef DwarfDebugProducer; 169 170 /// The maximum version of dwarf that we should emit. 171 uint16_t DwarfVersion; 172 173 /// Honor temporary labels, this is useful for debugging semantic 174 /// differences between temporary and non-temporary labels (primarily on 175 /// Darwin). 176 bool AllowTemporaryLabels; 177 bool UseNamesOnTempLabels = true; 178 179 /// The Compile Unit ID that we are currently processing. 180 unsigned DwarfCompileUnitID; 181 182 struct ELFSectionKey { 183 std::string SectionName; 184 StringRef GroupName; 185 unsigned UniqueID; 186 ELFSectionKey(StringRef SectionName, StringRef GroupName, 187 unsigned UniqueID) 188 : SectionName(SectionName), GroupName(GroupName), UniqueID(UniqueID) { 189 } 190 bool operator<(const ELFSectionKey &Other) const { 191 if (SectionName != Other.SectionName) 192 return SectionName < Other.SectionName; 193 if (GroupName != Other.GroupName) 194 return GroupName < Other.GroupName; 195 return UniqueID < Other.UniqueID; 196 } 197 }; 198 199 struct COFFSectionKey { 200 std::string SectionName; 201 StringRef GroupName; 202 int SelectionKey; 203 unsigned UniqueID; 204 COFFSectionKey(StringRef SectionName, StringRef GroupName, 205 int SelectionKey, unsigned UniqueID) 206 : SectionName(SectionName), GroupName(GroupName), 207 SelectionKey(SelectionKey), UniqueID(UniqueID) {} 208 bool operator<(const COFFSectionKey &Other) const { 209 if (SectionName != Other.SectionName) 210 return SectionName < Other.SectionName; 211 if (GroupName != Other.GroupName) 212 return GroupName < Other.GroupName; 213 if (SelectionKey != Other.SelectionKey) 214 return SelectionKey < Other.SelectionKey; 215 return UniqueID < Other.UniqueID; 216 } 217 }; 218 219 StringMap<MCSectionMachO *> MachOUniquingMap; 220 std::map<ELFSectionKey, MCSectionELF *> ELFUniquingMap; 221 std::map<COFFSectionKey, MCSectionCOFF *> COFFUniquingMap; 222 StringMap<bool> ELFRelSecNames; 223 224 SpecificBumpPtrAllocator<MCSubtargetInfo> MCSubtargetAllocator; 225 226 /// Do automatic reset in destructor 227 bool AutoReset; 228 229 bool HadError; 230 231 MCSymbol *createSymbolImpl(const StringMapEntry<bool> *Name, 232 bool CanBeUnnamed); 233 MCSymbol *createSymbol(StringRef Name, bool AlwaysAddSuffix, 234 bool IsTemporary); 235 236 MCSymbol *getOrCreateDirectionalLocalSymbol(unsigned LocalLabelVal, 237 unsigned Instance); 238 239 public: 240 explicit MCContext(const MCAsmInfo *MAI, const MCRegisterInfo *MRI, 241 const MCObjectFileInfo *MOFI, 242 const SourceMgr *Mgr = nullptr, bool DoAutoReset = true); 243 ~MCContext(); 244 245 const SourceMgr *getSourceManager() const { return SrcMgr; } 246 247 const MCAsmInfo *getAsmInfo() const { return MAI; } 248 249 const MCRegisterInfo *getRegisterInfo() const { return MRI; } 250 251 const MCObjectFileInfo *getObjectFileInfo() const { return MOFI; } 252 253 CodeViewContext &getCVContext(); 254 255 void setAllowTemporaryLabels(bool Value) { AllowTemporaryLabels = Value; } 256 void setUseNamesOnTempLabels(bool Value) { UseNamesOnTempLabels = Value; } 257 258 /// \name Module Lifetime Management 259 /// @{ 260 261 /// reset - return object to right after construction state to prepare 262 /// to process a new module 263 void reset(); 264 265 /// @} 266 267 /// \name Symbol Management 268 /// @{ 269 270 /// Create and return a new linker temporary symbol with a unique but 271 /// unspecified name. 272 MCSymbol *createLinkerPrivateTempSymbol(); 273 274 /// Create and return a new assembler temporary symbol with a unique but 275 /// unspecified name. 276 MCSymbol *createTempSymbol(bool CanBeUnnamed = true); 277 278 MCSymbol *createTempSymbol(const Twine &Name, bool AlwaysAddSuffix, 279 bool CanBeUnnamed = true); 280 281 /// Create the definition of a directional local symbol for numbered label 282 /// (used for "1:" definitions). 283 MCSymbol *createDirectionalLocalSymbol(unsigned LocalLabelVal); 284 285 /// Create and return a directional local symbol for numbered label (used 286 /// for "1b" or 1f" references). 287 MCSymbol *getDirectionalLocalSymbol(unsigned LocalLabelVal, bool Before); 288 289 /// Lookup the symbol inside with the specified \p Name. If it exists, 290 /// return it. If not, create a forward reference and return it. 291 /// 292 /// \param Name - The symbol name, which must be unique across all symbols. 293 MCSymbol *getOrCreateSymbol(const Twine &Name); 294 295 MCSymbolELF *getOrCreateSectionSymbol(const MCSectionELF &Section); 296 297 /// Gets a symbol that will be defined to the final stack offset of a local 298 /// variable after codegen. 299 /// 300 /// \param Idx - The index of a local variable passed to @llvm.localescape. 301 MCSymbol *getOrCreateFrameAllocSymbol(StringRef FuncName, unsigned Idx); 302 303 MCSymbol *getOrCreateParentFrameOffsetSymbol(StringRef FuncName); 304 305 MCSymbol *getOrCreateLSDASymbol(StringRef FuncName); 306 307 /// Get the symbol for \p Name, or null. 308 MCSymbol *lookupSymbol(const Twine &Name) const; 309 310 /// getSymbols - Get a reference for the symbol table for clients that 311 /// want to, for example, iterate over all symbols. 'const' because we 312 /// still want any modifications to the table itself to use the MCContext 313 /// APIs. 314 const SymbolTable &getSymbols() const { return Symbols; } 315 316 /// @} 317 318 /// \name Section Management 319 /// @{ 320 321 enum : unsigned { 322 /// Pass this value as the UniqueID during section creation to get the 323 /// generic section with the given name and characteristics. The usual 324 /// sections such as .text use this ID. 325 GenericSectionID = ~0U 326 }; 327 328 /// Return the MCSection for the specified mach-o section. This requires 329 /// the operands to be valid. 330 MCSectionMachO *getMachOSection(StringRef Segment, StringRef Section, 331 unsigned TypeAndAttributes, 332 unsigned Reserved2, SectionKind K, 333 const char *BeginSymName = nullptr); 334 335 MCSectionMachO *getMachOSection(StringRef Segment, StringRef Section, 336 unsigned TypeAndAttributes, SectionKind K, 337 const char *BeginSymName = nullptr) { 338 return getMachOSection(Segment, Section, TypeAndAttributes, 0, K, 339 BeginSymName); 340 } 341 342 MCSectionELF *getELFSection(const Twine &Section, unsigned Type, 343 unsigned Flags) { 344 return getELFSection(Section, Type, Flags, nullptr); 345 } 346 347 MCSectionELF *getELFSection(const Twine &Section, unsigned Type, 348 unsigned Flags, const char *BeginSymName) { 349 return getELFSection(Section, Type, Flags, 0, "", BeginSymName); 350 } 351 352 MCSectionELF *getELFSection(const Twine &Section, unsigned Type, 353 unsigned Flags, unsigned EntrySize, 354 const Twine &Group) { 355 return getELFSection(Section, Type, Flags, EntrySize, Group, nullptr); 356 } 357 358 MCSectionELF *getELFSection(const Twine &Section, unsigned Type, 359 unsigned Flags, unsigned EntrySize, 360 const Twine &Group, const char *BeginSymName) { 361 return getELFSection(Section, Type, Flags, EntrySize, Group, ~0, 362 BeginSymName); 363 } 364 365 MCSectionELF *getELFSection(const Twine &Section, unsigned Type, 366 unsigned Flags, unsigned EntrySize, 367 const Twine &Group, unsigned UniqueID) { 368 return getELFSection(Section, Type, Flags, EntrySize, Group, UniqueID, 369 nullptr); 370 } 371 372 MCSectionELF *getELFSection(const Twine &Section, unsigned Type, 373 unsigned Flags, unsigned EntrySize, 374 const Twine &Group, unsigned UniqueID, 375 const char *BeginSymName); 376 377 MCSectionELF *getELFSection(const Twine &Section, unsigned Type, 378 unsigned Flags, unsigned EntrySize, 379 const MCSymbolELF *Group, unsigned UniqueID, 380 const char *BeginSymName, 381 const MCSectionELF *Associated); 382 383 /// Get a section with the provided group identifier. This section is 384 /// named by concatenating \p Prefix with '.' then \p Suffix. The \p Type 385 /// describes the type of the section and \p Flags are used to further 386 /// configure this named section. 387 MCSectionELF *getELFNamedSection(const Twine &Prefix, const Twine &Suffix, 388 unsigned Type, unsigned Flags, 389 unsigned EntrySize = 0); 390 391 MCSectionELF *createELFRelSection(const Twine &Name, unsigned Type, 392 unsigned Flags, unsigned EntrySize, 393 const MCSymbolELF *Group, 394 const MCSectionELF *Associated); 395 396 void renameELFSection(MCSectionELF *Section, StringRef Name); 397 398 MCSectionELF *createELFGroupSection(const MCSymbolELF *Group); 399 400 MCSectionCOFF *getCOFFSection(StringRef Section, unsigned Characteristics, 401 SectionKind Kind, StringRef COMDATSymName, 402 int Selection, 403 unsigned UniqueID = GenericSectionID, 404 const char *BeginSymName = nullptr); 405 406 MCSectionCOFF *getCOFFSection(StringRef Section, unsigned Characteristics, 407 SectionKind Kind, 408 const char *BeginSymName = nullptr); 409 410 MCSectionCOFF *getCOFFSection(StringRef Section); 411 412 /// Gets or creates a section equivalent to Sec that is associated with the 413 /// section containing KeySym. For example, to create a debug info section 414 /// associated with an inline function, pass the normal debug info section 415 /// as Sec and the function symbol as KeySym. 416 MCSectionCOFF * 417 getAssociativeCOFFSection(MCSectionCOFF *Sec, const MCSymbol *KeySym, 418 unsigned UniqueID = GenericSectionID); 419 420 // Create and save a copy of STI and return a reference to the copy. 421 MCSubtargetInfo &getSubtargetCopy(const MCSubtargetInfo &STI); 422 423 /// @} 424 425 /// \name Dwarf Management 426 /// @{ 427 428 /// \brief Get the compilation directory for DW_AT_comp_dir 429 /// The compilation directory should be set with \c setCompilationDir before 430 /// calling this function. If it is unset, an empty string will be returned. 431 StringRef getCompilationDir() const { return CompilationDir; } 432 433 /// \brief Set the compilation directory for DW_AT_comp_dir 434 void setCompilationDir(StringRef S) { CompilationDir = S.str(); } 435 436 /// \brief Get the main file name for use in error messages and debug 437 /// info. This can be set to ensure we've got the correct file name 438 /// after preprocessing or for -save-temps. 439 const std::string &getMainFileName() const { return MainFileName; } 440 441 /// \brief Set the main file name and override the default. 442 void setMainFileName(StringRef S) { MainFileName = S; } 443 444 /// Creates an entry in the dwarf file and directory tables. 445 unsigned getDwarfFile(StringRef Directory, StringRef FileName, 446 unsigned FileNumber, unsigned CUID); 447 448 bool isValidDwarfFileNumber(unsigned FileNumber, unsigned CUID = 0); 449 450 const std::map<unsigned, MCDwarfLineTable> &getMCDwarfLineTables() const { 451 return MCDwarfLineTablesCUMap; 452 } 453 454 MCDwarfLineTable &getMCDwarfLineTable(unsigned CUID) { 455 return MCDwarfLineTablesCUMap[CUID]; 456 } 457 458 const MCDwarfLineTable &getMCDwarfLineTable(unsigned CUID) const { 459 auto I = MCDwarfLineTablesCUMap.find(CUID); 460 assert(I != MCDwarfLineTablesCUMap.end()); 461 return I->second; 462 } 463 464 const SmallVectorImpl<MCDwarfFile> &getMCDwarfFiles(unsigned CUID = 0) { 465 return getMCDwarfLineTable(CUID).getMCDwarfFiles(); 466 } 467 const SmallVectorImpl<std::string> &getMCDwarfDirs(unsigned CUID = 0) { 468 return getMCDwarfLineTable(CUID).getMCDwarfDirs(); 469 } 470 471 bool hasMCLineSections() const { 472 for (const auto &Table : MCDwarfLineTablesCUMap) 473 if (!Table.second.getMCDwarfFiles().empty() || Table.second.getLabel()) 474 return true; 475 return false; 476 } 477 unsigned getDwarfCompileUnitID() { return DwarfCompileUnitID; } 478 void setDwarfCompileUnitID(unsigned CUIndex) { 479 DwarfCompileUnitID = CUIndex; 480 } 481 void setMCLineTableCompilationDir(unsigned CUID, StringRef CompilationDir) { 482 getMCDwarfLineTable(CUID).setCompilationDir(CompilationDir); 483 } 484 485 /// Saves the information from the currently parsed dwarf .loc directive 486 /// and sets DwarfLocSeen. When the next instruction is assembled an entry 487 /// in the line number table with this information and the address of the 488 /// instruction will be created. 489 void setCurrentDwarfLoc(unsigned FileNum, unsigned Line, unsigned Column, 490 unsigned Flags, unsigned Isa, 491 unsigned Discriminator) { 492 CurrentDwarfLoc.setFileNum(FileNum); 493 CurrentDwarfLoc.setLine(Line); 494 CurrentDwarfLoc.setColumn(Column); 495 CurrentDwarfLoc.setFlags(Flags); 496 CurrentDwarfLoc.setIsa(Isa); 497 CurrentDwarfLoc.setDiscriminator(Discriminator); 498 DwarfLocSeen = true; 499 } 500 void clearDwarfLocSeen() { DwarfLocSeen = false; } 501 502 bool getDwarfLocSeen() { return DwarfLocSeen; } 503 const MCDwarfLoc &getCurrentDwarfLoc() { return CurrentDwarfLoc; } 504 505 bool getGenDwarfForAssembly() { return GenDwarfForAssembly; } 506 void setGenDwarfForAssembly(bool Value) { GenDwarfForAssembly = Value; } 507 unsigned getGenDwarfFileNumber() { return GenDwarfFileNumber; } 508 void setGenDwarfFileNumber(unsigned FileNumber) { 509 GenDwarfFileNumber = FileNumber; 510 } 511 const SetVector<MCSection *> &getGenDwarfSectionSyms() { 512 return SectionsForRanges; 513 } 514 bool addGenDwarfSection(MCSection *Sec) { 515 return SectionsForRanges.insert(Sec); 516 } 517 518 void finalizeDwarfSections(MCStreamer &MCOS); 519 const std::vector<MCGenDwarfLabelEntry> &getMCGenDwarfLabelEntries() const { 520 return MCGenDwarfLabelEntries; 521 } 522 void addMCGenDwarfLabelEntry(const MCGenDwarfLabelEntry &E) { 523 MCGenDwarfLabelEntries.push_back(E); 524 } 525 526 void setDwarfDebugFlags(StringRef S) { DwarfDebugFlags = S; } 527 StringRef getDwarfDebugFlags() { return DwarfDebugFlags; } 528 529 void setDwarfDebugProducer(StringRef S) { DwarfDebugProducer = S; } 530 StringRef getDwarfDebugProducer() { return DwarfDebugProducer; } 531 532 void setDwarfVersion(uint16_t v) { DwarfVersion = v; } 533 uint16_t getDwarfVersion() const { return DwarfVersion; } 534 535 /// @} 536 537 538 /// \name CodeView Management 539 /// @{ 540 541 /// Creates an entry in the cv file table. 542 unsigned getCVFile(StringRef FileName, unsigned FileNumber); 543 544 /// Saves the information from the currently parsed .cv_loc directive 545 /// and sets CVLocSeen. When the next instruction is assembled an entry 546 /// in the line number table with this information and the address of the 547 /// instruction will be created. 548 void setCurrentCVLoc(unsigned FunctionId, unsigned FileNo, unsigned Line, 549 unsigned Column, bool PrologueEnd, bool IsStmt) { 550 CurrentCVLoc.setFunctionId(FunctionId); 551 CurrentCVLoc.setFileNum(FileNo); 552 CurrentCVLoc.setLine(Line); 553 CurrentCVLoc.setColumn(Column); 554 CurrentCVLoc.setPrologueEnd(PrologueEnd); 555 CurrentCVLoc.setIsStmt(IsStmt); 556 CVLocSeen = true; 557 } 558 void clearCVLocSeen() { CVLocSeen = false; } 559 560 bool getCVLocSeen() { return CVLocSeen; } 561 const MCCVLoc &getCurrentCVLoc() { return CurrentCVLoc; } 562 563 bool isValidCVFileNumber(unsigned FileNumber); 564 /// @} 565 566 char *getSecureLogFile() { return SecureLogFile; } 567 raw_fd_ostream *getSecureLog() { return SecureLog.get(); } 568 bool getSecureLogUsed() { return SecureLogUsed; } 569 void setSecureLog(std::unique_ptr<raw_fd_ostream> Value) { 570 SecureLog = std::move(Value); 571 } 572 void setSecureLogUsed(bool Value) { SecureLogUsed = Value; } 573 574 void *allocate(unsigned Size, unsigned Align = 8) { 575 return Allocator.Allocate(Size, Align); 576 } 577 void deallocate(void *Ptr) {} 578 579 bool hadError() { return HadError; } 580 void reportError(SMLoc L, const Twine &Msg); 581 // Unrecoverable error has occurred. Display the best diagnostic we can 582 // and bail via exit(1). For now, most MC backend errors are unrecoverable. 583 // FIXME: We should really do something about that. 584 LLVM_ATTRIBUTE_NORETURN void reportFatalError(SMLoc L, 585 const Twine &Msg); 586 }; 587 588 } // end namespace llvm 589 590 // operator new and delete aren't allowed inside namespaces. 591 // The throw specifications are mandated by the standard. 592 /// \brief Placement new for using the MCContext's allocator. 593 /// 594 /// This placement form of operator new uses the MCContext's allocator for 595 /// obtaining memory. It is a non-throwing new, which means that it returns 596 /// null on error. (If that is what the allocator does. The current does, so if 597 /// this ever changes, this operator will have to be changed, too.) 598 /// Usage looks like this (assuming there's an MCContext 'Context' in scope): 599 /// \code 600 /// // Default alignment (8) 601 /// IntegerLiteral *Ex = new (Context) IntegerLiteral(arguments); 602 /// // Specific alignment 603 /// IntegerLiteral *Ex2 = new (Context, 4) IntegerLiteral(arguments); 604 /// \endcode 605 /// Please note that you cannot use delete on the pointer; it must be 606 /// deallocated using an explicit destructor call followed by 607 /// \c Context.Deallocate(Ptr). 608 /// 609 /// \param Bytes The number of bytes to allocate. Calculated by the compiler. 610 /// \param C The MCContext that provides the allocator. 611 /// \param Alignment The alignment of the allocated memory (if the underlying 612 /// allocator supports it). 613 /// \return The allocated memory. Could be NULL. 614 inline void *operator new(size_t Bytes, llvm::MCContext &C, 615 size_t Alignment = 8) LLVM_NOEXCEPT { 616 return C.allocate(Bytes, Alignment); 617 } 618 /// \brief Placement delete companion to the new above. 619 /// 620 /// This operator is just a companion to the new above. There is no way of 621 /// invoking it directly; see the new operator for more details. This operator 622 /// is called implicitly by the compiler if a placement new expression using 623 /// the MCContext throws in the object constructor. 624 inline void operator delete(void *Ptr, llvm::MCContext &C, 625 size_t) LLVM_NOEXCEPT { 626 C.deallocate(Ptr); 627 } 628 629 /// This placement form of operator new[] uses the MCContext's allocator for 630 /// obtaining memory. It is a non-throwing new[], which means that it returns 631 /// null on error. 632 /// Usage looks like this (assuming there's an MCContext 'Context' in scope): 633 /// \code 634 /// // Default alignment (8) 635 /// char *data = new (Context) char[10]; 636 /// // Specific alignment 637 /// char *data = new (Context, 4) char[10]; 638 /// \endcode 639 /// Please note that you cannot use delete on the pointer; it must be 640 /// deallocated using an explicit destructor call followed by 641 /// \c Context.Deallocate(Ptr). 642 /// 643 /// \param Bytes The number of bytes to allocate. Calculated by the compiler. 644 /// \param C The MCContext that provides the allocator. 645 /// \param Alignment The alignment of the allocated memory (if the underlying 646 /// allocator supports it). 647 /// \return The allocated memory. Could be NULL. 648 inline void *operator new[](size_t Bytes, llvm::MCContext &C, 649 size_t Alignment = 8) LLVM_NOEXCEPT { 650 return C.allocate(Bytes, Alignment); 651 } 652 653 /// \brief Placement delete[] companion to the new[] above. 654 /// 655 /// This operator is just a companion to the new[] above. There is no way of 656 /// invoking it directly; see the new[] operator for more details. This operator 657 /// is called implicitly by the compiler if a placement new[] expression using 658 /// the MCContext throws in the object constructor. 659 inline void operator delete[](void *Ptr, llvm::MCContext &C) LLVM_NOEXCEPT { 660 C.deallocate(Ptr); 661 } 662 663 #endif 664
