1 //===- MCStreamer.h - High-level Streaming Machine Code Output --*- C++ -*-===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 // 9 // This file declares the MCStreamer class. 10 // 11 //===----------------------------------------------------------------------===// 12 13 #ifndef LLVM_MC_MCSTREAMER_H 14 #define LLVM_MC_MCSTREAMER_H 15 16 #include "llvm/ADT/APInt.h" 17 #include "llvm/ADT/ArrayRef.h" 18 #include "llvm/ADT/DenseMap.h" 19 #include "llvm/ADT/Optional.h" 20 #include "llvm/ADT/SmallVector.h" 21 #include "llvm/ADT/StringRef.h" 22 #include "llvm/MC/MCDirectives.h" 23 #include "llvm/MC/MCLinkerOptimizationHint.h" 24 #include "llvm/MC/MCPseudoProbe.h" 25 #include "llvm/MC/MCSymbol.h" 26 #include "llvm/MC/MCWinEH.h" 27 #include "llvm/Support/Error.h" 28 #include "llvm/Support/MD5.h" 29 #include "llvm/Support/SMLoc.h" 30 #include "llvm/Support/TargetParser.h" 31 #include "llvm/Support/VersionTuple.h" 32 #include <cassert> 33 #include <cstdint> 34 #include <memory> 35 #include <string> 36 #include <utility> 37 #include <vector> 38 39 namespace llvm { 40 41 class AssemblerConstantPools; 42 class MCAsmBackend; 43 class MCCodeEmitter; 44 class MCContext; 45 struct MCDwarfFrameInfo; 46 class MCExpr; 47 class MCInst; 48 class MCInstPrinter; 49 class MCRegister; 50 class MCSection; 51 class MCStreamer; 52 class MCSymbolRefExpr; 53 class MCSubtargetInfo; 54 class raw_ostream; 55 class Twine; 56 57 namespace codeview { 58 struct DefRangeRegisterRelHeader; 59 struct DefRangeSubfieldRegisterHeader; 60 struct DefRangeRegisterHeader; 61 struct DefRangeFramePointerRelHeader; 62 } 63 64 using MCSectionSubPair = std::pair<MCSection *, const MCExpr *>; 65 66 /// Target specific streamer interface. This is used so that targets can 67 /// implement support for target specific assembly directives. 68 /// 69 /// If target foo wants to use this, it should implement 3 classes: 70 /// * FooTargetStreamer : public MCTargetStreamer 71 /// * FooTargetAsmStreamer : public FooTargetStreamer 72 /// * FooTargetELFStreamer : public FooTargetStreamer 73 /// 74 /// FooTargetStreamer should have a pure virtual method for each directive. For 75 /// example, for a ".bar symbol_name" directive, it should have 76 /// virtual emitBar(const MCSymbol &Symbol) = 0; 77 /// 78 /// The FooTargetAsmStreamer and FooTargetELFStreamer classes implement the 79 /// method. The assembly streamer just prints ".bar symbol_name". The object 80 /// streamer does whatever is needed to implement .bar in the object file. 81 /// 82 /// In the assembly printer and parser the target streamer can be used by 83 /// calling getTargetStreamer and casting it to FooTargetStreamer: 84 /// 85 /// MCTargetStreamer &TS = OutStreamer.getTargetStreamer(); 86 /// FooTargetStreamer &ATS = static_cast<FooTargetStreamer &>(TS); 87 /// 88 /// The base classes FooTargetAsmStreamer and FooTargetELFStreamer should 89 /// *never* be treated differently. Callers should always talk to a 90 /// FooTargetStreamer. 91 class MCTargetStreamer { 92 protected: 93 MCStreamer &Streamer; 94 95 public: 96 MCTargetStreamer(MCStreamer &S); 97 virtual ~MCTargetStreamer(); 98 getStreamer()99 MCStreamer &getStreamer() { return Streamer; } 100 101 // Allow a target to add behavior to the EmitLabel of MCStreamer. 102 virtual void emitLabel(MCSymbol *Symbol); 103 // Allow a target to add behavior to the emitAssignment of MCStreamer. 104 virtual void emitAssignment(MCSymbol *Symbol, const MCExpr *Value); 105 106 virtual void prettyPrintAsm(MCInstPrinter &InstPrinter, uint64_t Address, 107 const MCInst &Inst, const MCSubtargetInfo &STI, 108 raw_ostream &OS); 109 110 virtual void emitDwarfFileDirective(StringRef Directive); 111 112 /// Update streamer for a new active section. 113 /// 114 /// This is called by PopSection and SwitchSection, if the current 115 /// section changes. 116 virtual void changeSection(const MCSection *CurSection, MCSection *Section, 117 const MCExpr *SubSection, raw_ostream &OS); 118 119 virtual void emitValue(const MCExpr *Value); 120 121 /// Emit the bytes in \p Data into the output. 122 /// 123 /// This is used to emit bytes in \p Data as sequence of .byte directives. 124 virtual void emitRawBytes(StringRef Data); 125 126 virtual void finish(); 127 }; 128 129 // FIXME: declared here because it is used from 130 // lib/CodeGen/AsmPrinter/ARMException.cpp. 131 class ARMTargetStreamer : public MCTargetStreamer { 132 public: 133 ARMTargetStreamer(MCStreamer &S); 134 ~ARMTargetStreamer() override; 135 136 virtual void emitFnStart(); 137 virtual void emitFnEnd(); 138 virtual void emitCantUnwind(); 139 virtual void emitPersonality(const MCSymbol *Personality); 140 virtual void emitPersonalityIndex(unsigned Index); 141 virtual void emitHandlerData(); 142 virtual void emitSetFP(unsigned FpReg, unsigned SpReg, 143 int64_t Offset = 0); 144 virtual void emitMovSP(unsigned Reg, int64_t Offset = 0); 145 virtual void emitPad(int64_t Offset); 146 virtual void emitRegSave(const SmallVectorImpl<unsigned> &RegList, 147 bool isVector); 148 virtual void emitUnwindRaw(int64_t StackOffset, 149 const SmallVectorImpl<uint8_t> &Opcodes); 150 151 virtual void switchVendor(StringRef Vendor); 152 virtual void emitAttribute(unsigned Attribute, unsigned Value); 153 virtual void emitTextAttribute(unsigned Attribute, StringRef String); 154 virtual void emitIntTextAttribute(unsigned Attribute, unsigned IntValue, 155 StringRef StringValue = ""); 156 virtual void emitFPU(unsigned FPU); 157 virtual void emitArch(ARM::ArchKind Arch); 158 virtual void emitArchExtension(uint64_t ArchExt); 159 virtual void emitObjectArch(ARM::ArchKind Arch); 160 void emitTargetAttributes(const MCSubtargetInfo &STI); 161 virtual void finishAttributeSection(); 162 virtual void emitInst(uint32_t Inst, char Suffix = '\0'); 163 164 virtual void AnnotateTLSDescriptorSequence(const MCSymbolRefExpr *SRE); 165 166 virtual void emitThumbSet(MCSymbol *Symbol, const MCExpr *Value); 167 168 void finish() override; 169 170 /// Reset any state between object emissions, i.e. the equivalent of 171 /// MCStreamer's reset method. 172 virtual void reset(); 173 174 /// Callback used to implement the ldr= pseudo. 175 /// Add a new entry to the constant pool for the current section and return an 176 /// MCExpr that can be used to refer to the constant pool location. 177 const MCExpr *addConstantPoolEntry(const MCExpr *, SMLoc Loc); 178 179 /// Callback used to implement the .ltorg directive. 180 /// Emit contents of constant pool for the current section. 181 void emitCurrentConstantPool(); 182 183 private: 184 std::unique_ptr<AssemblerConstantPools> ConstantPools; 185 }; 186 187 /// Streaming machine code generation interface. 188 /// 189 /// This interface is intended to provide a programmatic interface that is very 190 /// similar to the level that an assembler .s file provides. It has callbacks 191 /// to emit bytes, handle directives, etc. The implementation of this interface 192 /// retains state to know what the current section is etc. 193 /// 194 /// There are multiple implementations of this interface: one for writing out 195 /// a .s file, and implementations that write out .o files of various formats. 196 /// 197 class MCStreamer { 198 MCContext &Context; 199 std::unique_ptr<MCTargetStreamer> TargetStreamer; 200 201 std::vector<MCDwarfFrameInfo> DwarfFrameInfos; 202 MCDwarfFrameInfo *getCurrentDwarfFrameInfo(); 203 204 /// Similar to DwarfFrameInfos, but for SEH unwind info. Chained frames may 205 /// refer to each other, so use std::unique_ptr to provide pointer stability. 206 std::vector<std::unique_ptr<WinEH::FrameInfo>> WinFrameInfos; 207 208 WinEH::FrameInfo *CurrentWinFrameInfo; 209 size_t CurrentProcWinFrameInfoStartIndex; 210 211 /// Tracks an index to represent the order a symbol was emitted in. 212 /// Zero means we did not emit that symbol. 213 DenseMap<const MCSymbol *, unsigned> SymbolOrdering; 214 215 /// This is stack of current and previous section values saved by 216 /// PushSection. 217 SmallVector<std::pair<MCSectionSubPair, MCSectionSubPair>, 4> SectionStack; 218 219 /// Pointer to the parser's SMLoc if available. This is used to provide 220 /// locations for diagnostics. 221 const SMLoc *StartTokLocPtr = nullptr; 222 223 /// The next unique ID to use when creating a WinCFI-related section (.pdata 224 /// or .xdata). This ID ensures that we have a one-to-one mapping from 225 /// code section to unwind info section, which MSVC's incremental linker 226 /// requires. 227 unsigned NextWinCFIID = 0; 228 229 bool UseAssemblerInfoForParsing; 230 231 /// Is the assembler allowed to insert padding automatically? For 232 /// correctness reasons, we sometimes need to ensure instructions aren't 233 /// separated in unexpected ways. At the moment, this feature is only 234 /// useable from an integrated assembler, but assembly syntax is under 235 /// discussion for future inclusion. 236 bool AllowAutoPadding = false; 237 238 protected: 239 MCStreamer(MCContext &Ctx); 240 241 virtual void emitCFIStartProcImpl(MCDwarfFrameInfo &Frame); 242 virtual void emitCFIEndProcImpl(MCDwarfFrameInfo &CurFrame); 243 getCurrentWinFrameInfo()244 WinEH::FrameInfo *getCurrentWinFrameInfo() { 245 return CurrentWinFrameInfo; 246 } 247 248 virtual void EmitWindowsUnwindTables(WinEH::FrameInfo *Frame); 249 250 virtual void EmitWindowsUnwindTables(); 251 252 virtual void emitRawTextImpl(StringRef String); 253 254 /// Returns true if the the .cv_loc directive is in the right section. 255 bool checkCVLocSection(unsigned FuncId, unsigned FileNo, SMLoc Loc); 256 257 public: 258 MCStreamer(const MCStreamer &) = delete; 259 MCStreamer &operator=(const MCStreamer &) = delete; 260 virtual ~MCStreamer(); 261 262 void visitUsedExpr(const MCExpr &Expr); 263 virtual void visitUsedSymbol(const MCSymbol &Sym); 264 setTargetStreamer(MCTargetStreamer * TS)265 void setTargetStreamer(MCTargetStreamer *TS) { 266 TargetStreamer.reset(TS); 267 } 268 setStartTokLocPtr(const SMLoc * Loc)269 void setStartTokLocPtr(const SMLoc *Loc) { StartTokLocPtr = Loc; } getStartTokLoc()270 SMLoc getStartTokLoc() const { 271 return StartTokLocPtr ? *StartTokLocPtr : SMLoc(); 272 } 273 274 /// State management 275 /// 276 virtual void reset(); 277 getContext()278 MCContext &getContext() const { return Context; } 279 getAssemblerPtr()280 virtual MCAssembler *getAssemblerPtr() { return nullptr; } 281 setUseAssemblerInfoForParsing(bool v)282 void setUseAssemblerInfoForParsing(bool v) { UseAssemblerInfoForParsing = v; } getUseAssemblerInfoForParsing()283 bool getUseAssemblerInfoForParsing() { return UseAssemblerInfoForParsing; } 284 getTargetStreamer()285 MCTargetStreamer *getTargetStreamer() { 286 return TargetStreamer.get(); 287 } 288 setAllowAutoPadding(bool v)289 void setAllowAutoPadding(bool v) { AllowAutoPadding = v; } getAllowAutoPadding()290 bool getAllowAutoPadding() const { return AllowAutoPadding; } 291 292 /// When emitting an object file, create and emit a real label. When emitting 293 /// textual assembly, this should do nothing to avoid polluting our output. 294 virtual MCSymbol *emitCFILabel(); 295 296 /// Retrieve the current frame info if one is available and it is not yet 297 /// closed. Otherwise, issue an error and return null. 298 WinEH::FrameInfo *EnsureValidWinFrameInfo(SMLoc Loc); 299 300 unsigned getNumFrameInfos(); 301 ArrayRef<MCDwarfFrameInfo> getDwarfFrameInfos() const; 302 303 bool hasUnfinishedDwarfFrameInfo(); 304 getNumWinFrameInfos()305 unsigned getNumWinFrameInfos() { return WinFrameInfos.size(); } getWinFrameInfos()306 ArrayRef<std::unique_ptr<WinEH::FrameInfo>> getWinFrameInfos() const { 307 return WinFrameInfos; 308 } 309 310 void generateCompactUnwindEncodings(MCAsmBackend *MAB); 311 312 /// \name Assembly File Formatting. 313 /// @{ 314 315 /// Return true if this streamer supports verbose assembly and if it is 316 /// enabled. isVerboseAsm()317 virtual bool isVerboseAsm() const { return false; } 318 319 /// Return true if this asm streamer supports emitting unformatted text 320 /// to the .s file with EmitRawText. hasRawTextSupport()321 virtual bool hasRawTextSupport() const { return false; } 322 323 /// Is the integrated assembler required for this streamer to function 324 /// correctly? isIntegratedAssemblerRequired()325 virtual bool isIntegratedAssemblerRequired() const { return false; } 326 327 /// Add a textual comment. 328 /// 329 /// Typically for comments that can be emitted to the generated .s 330 /// file if applicable as a QoI issue to make the output of the compiler 331 /// more readable. This only affects the MCAsmStreamer, and only when 332 /// verbose assembly output is enabled. 333 /// 334 /// If the comment includes embedded \n's, they will each get the comment 335 /// prefix as appropriate. The added comment should not end with a \n. 336 /// By default, each comment is terminated with an end of line, i.e. the 337 /// EOL param is set to true by default. If one prefers not to end the 338 /// comment with a new line then the EOL param should be passed 339 /// with a false value. 340 virtual void AddComment(const Twine &T, bool EOL = true) {} 341 342 /// Return a raw_ostream that comments can be written to. Unlike 343 /// AddComment, you are required to terminate comments with \n if you use this 344 /// method. 345 virtual raw_ostream &GetCommentOS(); 346 347 /// Print T and prefix it with the comment string (normally #) and 348 /// optionally a tab. This prints the comment immediately, not at the end of 349 /// the current line. It is basically a safe version of EmitRawText: since it 350 /// only prints comments, the object streamer ignores it instead of asserting. 351 virtual void emitRawComment(const Twine &T, bool TabPrefix = true); 352 353 /// Add explicit comment T. T is required to be a valid 354 /// comment in the output and does not need to be escaped. 355 virtual void addExplicitComment(const Twine &T); 356 357 /// Emit added explicit comments. 358 virtual void emitExplicitComments(); 359 360 /// AddBlankLine - Emit a blank line to a .s file to pretty it up. AddBlankLine()361 virtual void AddBlankLine() {} 362 363 /// @} 364 365 /// \name Symbol & Section Management 366 /// @{ 367 368 /// Return the current section that the streamer is emitting code to. getCurrentSection()369 MCSectionSubPair getCurrentSection() const { 370 if (!SectionStack.empty()) 371 return SectionStack.back().first; 372 return MCSectionSubPair(); 373 } getCurrentSectionOnly()374 MCSection *getCurrentSectionOnly() const { return getCurrentSection().first; } 375 376 /// Return the previous section that the streamer is emitting code to. getPreviousSection()377 MCSectionSubPair getPreviousSection() const { 378 if (!SectionStack.empty()) 379 return SectionStack.back().second; 380 return MCSectionSubPair(); 381 } 382 383 /// Returns an index to represent the order a symbol was emitted in. 384 /// (zero if we did not emit that symbol) GetSymbolOrder(const MCSymbol * Sym)385 unsigned GetSymbolOrder(const MCSymbol *Sym) const { 386 return SymbolOrdering.lookup(Sym); 387 } 388 389 /// Update streamer for a new active section. 390 /// 391 /// This is called by PopSection and SwitchSection, if the current 392 /// section changes. 393 virtual void changeSection(MCSection *, const MCExpr *); 394 395 /// Save the current and previous section on the section stack. PushSection()396 void PushSection() { 397 SectionStack.push_back( 398 std::make_pair(getCurrentSection(), getPreviousSection())); 399 } 400 401 /// Restore the current and previous section from the section stack. 402 /// Calls changeSection as needed. 403 /// 404 /// Returns false if the stack was empty. PopSection()405 bool PopSection() { 406 if (SectionStack.size() <= 1) 407 return false; 408 auto I = SectionStack.end(); 409 --I; 410 MCSectionSubPair OldSection = I->first; 411 --I; 412 MCSectionSubPair NewSection = I->first; 413 414 if (NewSection.first && OldSection != NewSection) 415 changeSection(NewSection.first, NewSection.second); 416 SectionStack.pop_back(); 417 return true; 418 } 419 SubSection(const MCExpr * Subsection)420 bool SubSection(const MCExpr *Subsection) { 421 if (SectionStack.empty()) 422 return false; 423 424 SwitchSection(SectionStack.back().first.first, Subsection); 425 return true; 426 } 427 428 /// Set the current section where code is being emitted to \p Section. This 429 /// is required to update CurSection. 430 /// 431 /// This corresponds to assembler directives like .section, .text, etc. 432 virtual void SwitchSection(MCSection *Section, 433 const MCExpr *Subsection = nullptr); 434 435 /// Set the current section where code is being emitted to \p Section. 436 /// This is required to update CurSection. This version does not call 437 /// changeSection. 438 void SwitchSectionNoChange(MCSection *Section, 439 const MCExpr *Subsection = nullptr) { 440 assert(Section && "Cannot switch to a null section!"); 441 MCSectionSubPair curSection = SectionStack.back().first; 442 SectionStack.back().second = curSection; 443 if (MCSectionSubPair(Section, Subsection) != curSection) 444 SectionStack.back().first = MCSectionSubPair(Section, Subsection); 445 } 446 447 /// Create the default sections and set the initial one. 448 virtual void InitSections(bool NoExecStack); 449 450 MCSymbol *endSection(MCSection *Section); 451 452 /// Sets the symbol's section. 453 /// 454 /// Each emitted symbol will be tracked in the ordering table, 455 /// so we can sort on them later. 456 void AssignFragment(MCSymbol *Symbol, MCFragment *Fragment); 457 458 /// Returns the mnemonic for \p MI, if the streamer has access to a 459 /// instruction printer and returns an empty string otherwise. getMnemonic(MCInst & MI)460 virtual StringRef getMnemonic(MCInst &MI) { return ""; } 461 462 /// Emit a label for \p Symbol into the current section. 463 /// 464 /// This corresponds to an assembler statement such as: 465 /// foo: 466 /// 467 /// \param Symbol - The symbol to emit. A given symbol should only be 468 /// emitted as a label once, and symbols emitted as a label should never be 469 /// used in an assignment. 470 // FIXME: These emission are non-const because we mutate the symbol to 471 // add the section we're emitting it to later. 472 virtual void emitLabel(MCSymbol *Symbol, SMLoc Loc = SMLoc()); 473 474 virtual void emitEHSymAttributes(const MCSymbol *Symbol, MCSymbol *EHSymbol); 475 476 /// Note in the output the specified \p Flag. 477 virtual void emitAssemblerFlag(MCAssemblerFlag Flag); 478 479 /// Emit the given list \p Options of strings as linker 480 /// options into the output. emitLinkerOptions(ArrayRef<std::string> Kind)481 virtual void emitLinkerOptions(ArrayRef<std::string> Kind) {} 482 483 /// Note in the output the specified region \p Kind. emitDataRegion(MCDataRegionType Kind)484 virtual void emitDataRegion(MCDataRegionType Kind) {} 485 486 /// Specify the Mach-O minimum deployment target version. emitVersionMin(MCVersionMinType Type,unsigned Major,unsigned Minor,unsigned Update,VersionTuple SDKVersion)487 virtual void emitVersionMin(MCVersionMinType Type, unsigned Major, 488 unsigned Minor, unsigned Update, 489 VersionTuple SDKVersion) {} 490 491 /// Emit/Specify Mach-O build version command. 492 /// \p Platform should be one of MachO::PlatformType. emitBuildVersion(unsigned Platform,unsigned Major,unsigned Minor,unsigned Update,VersionTuple SDKVersion)493 virtual void emitBuildVersion(unsigned Platform, unsigned Major, 494 unsigned Minor, unsigned Update, 495 VersionTuple SDKVersion) {} 496 497 void emitVersionForTarget(const Triple &Target, 498 const VersionTuple &SDKVersion); 499 500 /// Note in the output that the specified \p Func is a Thumb mode 501 /// function (ARM target only). 502 virtual void emitThumbFunc(MCSymbol *Func); 503 504 /// Emit an assignment of \p Value to \p Symbol. 505 /// 506 /// This corresponds to an assembler statement such as: 507 /// symbol = value 508 /// 509 /// The assignment generates no code, but has the side effect of binding the 510 /// value in the current context. For the assembly streamer, this prints the 511 /// binding into the .s file. 512 /// 513 /// \param Symbol - The symbol being assigned to. 514 /// \param Value - The value for the symbol. 515 virtual void emitAssignment(MCSymbol *Symbol, const MCExpr *Value); 516 517 /// Emit an weak reference from \p Alias to \p Symbol. 518 /// 519 /// This corresponds to an assembler statement such as: 520 /// .weakref alias, symbol 521 /// 522 /// \param Alias - The alias that is being created. 523 /// \param Symbol - The symbol being aliased. 524 virtual void emitWeakReference(MCSymbol *Alias, const MCSymbol *Symbol); 525 526 /// Add the given \p Attribute to \p Symbol. 527 virtual bool emitSymbolAttribute(MCSymbol *Symbol, 528 MCSymbolAttr Attribute) = 0; 529 530 /// Set the \p DescValue for the \p Symbol. 531 /// 532 /// \param Symbol - The symbol to have its n_desc field set. 533 /// \param DescValue - The value to set into the n_desc field. 534 virtual void emitSymbolDesc(MCSymbol *Symbol, unsigned DescValue); 535 536 /// Start emitting COFF symbol definition 537 /// 538 /// \param Symbol - The symbol to have its External & Type fields set. 539 virtual void BeginCOFFSymbolDef(const MCSymbol *Symbol); 540 541 /// Emit the storage class of the symbol. 542 /// 543 /// \param StorageClass - The storage class the symbol should have. 544 virtual void EmitCOFFSymbolStorageClass(int StorageClass); 545 546 /// Emit the type of the symbol. 547 /// 548 /// \param Type - A COFF type identifier (see COFF::SymbolType in X86COFF.h) 549 virtual void EmitCOFFSymbolType(int Type); 550 551 /// Marks the end of the symbol definition. 552 virtual void EndCOFFSymbolDef(); 553 554 virtual void EmitCOFFSafeSEH(MCSymbol const *Symbol); 555 556 /// Emits the symbol table index of a Symbol into the current section. 557 virtual void EmitCOFFSymbolIndex(MCSymbol const *Symbol); 558 559 /// Emits a COFF section index. 560 /// 561 /// \param Symbol - Symbol the section number relocation should point to. 562 virtual void EmitCOFFSectionIndex(MCSymbol const *Symbol); 563 564 /// Emits a COFF section relative relocation. 565 /// 566 /// \param Symbol - Symbol the section relative relocation should point to. 567 virtual void EmitCOFFSecRel32(MCSymbol const *Symbol, uint64_t Offset); 568 569 /// Emits a COFF image relative relocation. 570 /// 571 /// \param Symbol - Symbol the image relative relocation should point to. 572 virtual void EmitCOFFImgRel32(MCSymbol const *Symbol, int64_t Offset); 573 574 /// Emits an lcomm directive with XCOFF csect information. 575 /// 576 /// \param LabelSym - Label on the block of storage. 577 /// \param Size - The size of the block of storage. 578 /// \param CsectSym - Csect name for the block of storage. 579 /// \param ByteAlignment - The alignment of the symbol in bytes. Must be a 580 /// power of 2. 581 virtual void emitXCOFFLocalCommonSymbol(MCSymbol *LabelSym, uint64_t Size, 582 MCSymbol *CsectSym, 583 unsigned ByteAlignment); 584 585 /// Emit a symbol's linkage and visibility with a linkage directive for XCOFF. 586 /// 587 /// \param Symbol - The symbol to emit. 588 /// \param Linkage - The linkage of the symbol to emit. 589 /// \param Visibility - The visibility of the symbol to emit or MCSA_Invalid 590 /// if the symbol does not have an explicit visibility. 591 virtual void emitXCOFFSymbolLinkageWithVisibility(MCSymbol *Symbol, 592 MCSymbolAttr Linkage, 593 MCSymbolAttr Visibility); 594 595 /// Emit a XCOFF .rename directive which creates a synonym for an illegal or 596 /// undesirable name. 597 /// 598 /// \param Name - The name used internally in the assembly for references to 599 /// the symbol. 600 /// \param Rename - The value to which the Name parameter is 601 /// changed at the end of assembly. 602 virtual void emitXCOFFRenameDirective(const MCSymbol *Name, StringRef Rename); 603 604 /// Emit an ELF .size directive. 605 /// 606 /// This corresponds to an assembler statement such as: 607 /// .size symbol, expression 608 virtual void emitELFSize(MCSymbol *Symbol, const MCExpr *Value); 609 610 /// Emit an ELF .symver directive. 611 /// 612 /// This corresponds to an assembler statement such as: 613 /// .symver _start, foo@@SOME_VERSION 614 virtual void emitELFSymverDirective(const MCSymbol *OriginalSym, 615 StringRef Name, bool KeepOriginalSym); 616 617 /// Emit a Linker Optimization Hint (LOH) directive. 618 /// \param Args - Arguments of the LOH. emitLOHDirective(MCLOHType Kind,const MCLOHArgs & Args)619 virtual void emitLOHDirective(MCLOHType Kind, const MCLOHArgs &Args) {} 620 621 /// Emit a common symbol. 622 /// 623 /// \param Symbol - The common symbol to emit. 624 /// \param Size - The size of the common symbol. 625 /// \param ByteAlignment - The alignment of the symbol if 626 /// non-zero. This must be a power of 2. 627 virtual void emitCommonSymbol(MCSymbol *Symbol, uint64_t Size, 628 unsigned ByteAlignment) = 0; 629 630 /// Emit a local common (.lcomm) symbol. 631 /// 632 /// \param Symbol - The common symbol to emit. 633 /// \param Size - The size of the common symbol. 634 /// \param ByteAlignment - The alignment of the common symbol in bytes. 635 virtual void emitLocalCommonSymbol(MCSymbol *Symbol, uint64_t Size, 636 unsigned ByteAlignment); 637 638 /// Emit the zerofill section and an optional symbol. 639 /// 640 /// \param Section - The zerofill section to create and or to put the symbol 641 /// \param Symbol - The zerofill symbol to emit, if non-NULL. 642 /// \param Size - The size of the zerofill symbol. 643 /// \param ByteAlignment - The alignment of the zerofill symbol if 644 /// non-zero. This must be a power of 2 on some targets. 645 virtual void emitZerofill(MCSection *Section, MCSymbol *Symbol = nullptr, 646 uint64_t Size = 0, unsigned ByteAlignment = 0, 647 SMLoc Loc = SMLoc()) = 0; 648 649 /// Emit a thread local bss (.tbss) symbol. 650 /// 651 /// \param Section - The thread local common section. 652 /// \param Symbol - The thread local common symbol to emit. 653 /// \param Size - The size of the symbol. 654 /// \param ByteAlignment - The alignment of the thread local common symbol 655 /// if non-zero. This must be a power of 2 on some targets. 656 virtual void emitTBSSSymbol(MCSection *Section, MCSymbol *Symbol, 657 uint64_t Size, unsigned ByteAlignment = 0); 658 659 /// @} 660 /// \name Generating Data 661 /// @{ 662 663 /// Emit the bytes in \p Data into the output. 664 /// 665 /// This is used to implement assembler directives such as .byte, .ascii, 666 /// etc. 667 virtual void emitBytes(StringRef Data); 668 669 /// Functionally identical to EmitBytes. When emitting textual assembly, this 670 /// method uses .byte directives instead of .ascii or .asciz for readability. 671 virtual void emitBinaryData(StringRef Data); 672 673 /// Emit the expression \p Value into the output as a native 674 /// integer of the given \p Size bytes. 675 /// 676 /// This is used to implement assembler directives such as .word, .quad, 677 /// etc. 678 /// 679 /// \param Value - The value to emit. 680 /// \param Size - The size of the integer (in bytes) to emit. This must 681 /// match a native machine width. 682 /// \param Loc - The location of the expression for error reporting. 683 virtual void emitValueImpl(const MCExpr *Value, unsigned Size, 684 SMLoc Loc = SMLoc()); 685 686 void emitValue(const MCExpr *Value, unsigned Size, SMLoc Loc = SMLoc()); 687 688 /// Special case of EmitValue that avoids the client having 689 /// to pass in a MCExpr for constant integers. 690 virtual void emitIntValue(uint64_t Value, unsigned Size); 691 virtual void emitIntValue(APInt Value); 692 693 /// Special case of EmitValue that avoids the client having to pass 694 /// in a MCExpr for constant integers & prints in Hex format for certain 695 /// modes. emitIntValueInHex(uint64_t Value,unsigned Size)696 virtual void emitIntValueInHex(uint64_t Value, unsigned Size) { 697 emitIntValue(Value, Size); 698 } 699 emitInt8(uint64_t Value)700 void emitInt8(uint64_t Value) { emitIntValue(Value, 1); } emitInt16(uint64_t Value)701 void emitInt16(uint64_t Value) { emitIntValue(Value, 2); } emitInt32(uint64_t Value)702 void emitInt32(uint64_t Value) { emitIntValue(Value, 4); } emitInt64(uint64_t Value)703 void emitInt64(uint64_t Value) { emitIntValue(Value, 8); } 704 705 /// Special case of EmitValue that avoids the client having to pass 706 /// in a MCExpr for constant integers & prints in Hex format for certain 707 /// modes, pads the field with leading zeros to Size width emitIntValueInHexWithPadding(uint64_t Value,unsigned Size)708 virtual void emitIntValueInHexWithPadding(uint64_t Value, unsigned Size) { 709 emitIntValue(Value, Size); 710 } 711 712 virtual void emitULEB128Value(const MCExpr *Value); 713 714 virtual void emitSLEB128Value(const MCExpr *Value); 715 716 /// Special case of EmitULEB128Value that avoids the client having to 717 /// pass in a MCExpr for constant integers. 718 void emitULEB128IntValue(uint64_t Value, unsigned PadTo = 0); 719 720 /// Special case of EmitSLEB128Value that avoids the client having to 721 /// pass in a MCExpr for constant integers. 722 void emitSLEB128IntValue(int64_t Value); 723 724 /// Special case of EmitValue that avoids the client having to pass in 725 /// a MCExpr for MCSymbols. 726 void emitSymbolValue(const MCSymbol *Sym, unsigned Size, 727 bool IsSectionRelative = false); 728 729 /// Emit the expression \p Value into the output as a dtprel 730 /// (64-bit DTP relative) value. 731 /// 732 /// This is used to implement assembler directives such as .dtpreldword on 733 /// targets that support them. 734 virtual void emitDTPRel64Value(const MCExpr *Value); 735 736 /// Emit the expression \p Value into the output as a dtprel 737 /// (32-bit DTP relative) value. 738 /// 739 /// This is used to implement assembler directives such as .dtprelword on 740 /// targets that support them. 741 virtual void emitDTPRel32Value(const MCExpr *Value); 742 743 /// Emit the expression \p Value into the output as a tprel 744 /// (64-bit TP relative) value. 745 /// 746 /// This is used to implement assembler directives such as .tpreldword on 747 /// targets that support them. 748 virtual void emitTPRel64Value(const MCExpr *Value); 749 750 /// Emit the expression \p Value into the output as a tprel 751 /// (32-bit TP relative) value. 752 /// 753 /// This is used to implement assembler directives such as .tprelword on 754 /// targets that support them. 755 virtual void emitTPRel32Value(const MCExpr *Value); 756 757 /// Emit the expression \p Value into the output as a gprel64 (64-bit 758 /// GP relative) value. 759 /// 760 /// This is used to implement assembler directives such as .gpdword on 761 /// targets that support them. 762 virtual void emitGPRel64Value(const MCExpr *Value); 763 764 /// Emit the expression \p Value into the output as a gprel32 (32-bit 765 /// GP relative) value. 766 /// 767 /// This is used to implement assembler directives such as .gprel32 on 768 /// targets that support them. 769 virtual void emitGPRel32Value(const MCExpr *Value); 770 771 /// Emit NumBytes bytes worth of the value specified by FillValue. 772 /// This implements directives such as '.space'. 773 void emitFill(uint64_t NumBytes, uint8_t FillValue); 774 775 /// Emit \p Size bytes worth of the value specified by \p FillValue. 776 /// 777 /// This is used to implement assembler directives such as .space or .skip. 778 /// 779 /// \param NumBytes - The number of bytes to emit. 780 /// \param FillValue - The value to use when filling bytes. 781 /// \param Loc - The location of the expression for error reporting. 782 virtual void emitFill(const MCExpr &NumBytes, uint64_t FillValue, 783 SMLoc Loc = SMLoc()); 784 785 /// Emit \p NumValues copies of \p Size bytes. Each \p Size bytes is 786 /// taken from the lowest order 4 bytes of \p Expr expression. 787 /// 788 /// This is used to implement assembler directives such as .fill. 789 /// 790 /// \param NumValues - The number of copies of \p Size bytes to emit. 791 /// \param Size - The size (in bytes) of each repeated value. 792 /// \param Expr - The expression from which \p Size bytes are used. 793 virtual void emitFill(const MCExpr &NumValues, int64_t Size, int64_t Expr, 794 SMLoc Loc = SMLoc()); 795 796 virtual void emitNops(int64_t NumBytes, int64_t ControlledNopLength, 797 SMLoc Loc); 798 799 /// Emit NumBytes worth of zeros. 800 /// This function properly handles data in virtual sections. 801 void emitZeros(uint64_t NumBytes); 802 803 /// Emit some number of copies of \p Value until the byte alignment \p 804 /// ByteAlignment is reached. 805 /// 806 /// If the number of bytes need to emit for the alignment is not a multiple 807 /// of \p ValueSize, then the contents of the emitted fill bytes is 808 /// undefined. 809 /// 810 /// This used to implement the .align assembler directive. 811 /// 812 /// \param ByteAlignment - The alignment to reach. This must be a power of 813 /// two on some targets. 814 /// \param Value - The value to use when filling bytes. 815 /// \param ValueSize - The size of the integer (in bytes) to emit for 816 /// \p Value. This must match a native machine width. 817 /// \param MaxBytesToEmit - The maximum numbers of bytes to emit, or 0. If 818 /// the alignment cannot be reached in this many bytes, no bytes are 819 /// emitted. 820 virtual void emitValueToAlignment(unsigned ByteAlignment, int64_t Value = 0, 821 unsigned ValueSize = 1, 822 unsigned MaxBytesToEmit = 0); 823 824 /// Emit nops until the byte alignment \p ByteAlignment is reached. 825 /// 826 /// This used to align code where the alignment bytes may be executed. This 827 /// can emit different bytes for different sizes to optimize execution. 828 /// 829 /// \param ByteAlignment - The alignment to reach. This must be a power of 830 /// two on some targets. 831 /// \param MaxBytesToEmit - The maximum numbers of bytes to emit, or 0. If 832 /// the alignment cannot be reached in this many bytes, no bytes are 833 /// emitted. 834 virtual void emitCodeAlignment(unsigned ByteAlignment, 835 unsigned MaxBytesToEmit = 0); 836 837 /// Emit some number of copies of \p Value until the byte offset \p 838 /// Offset is reached. 839 /// 840 /// This is used to implement assembler directives such as .org. 841 /// 842 /// \param Offset - The offset to reach. This may be an expression, but the 843 /// expression must be associated with the current section. 844 /// \param Value - The value to use when filling bytes. 845 virtual void emitValueToOffset(const MCExpr *Offset, unsigned char Value, 846 SMLoc Loc); 847 848 /// @} 849 850 /// Switch to a new logical file. This is used to implement the '.file 851 /// "foo.c"' assembler directive. 852 virtual void emitFileDirective(StringRef Filename); 853 854 /// Emit the "identifiers" directive. This implements the 855 /// '.ident "version foo"' assembler directive. emitIdent(StringRef IdentString)856 virtual void emitIdent(StringRef IdentString) {} 857 858 /// Associate a filename with a specified logical file number. This 859 /// implements the DWARF2 '.file 4 "foo.c"' assembler directive. 860 unsigned emitDwarfFileDirective(unsigned FileNo, StringRef Directory, 861 StringRef Filename, 862 Optional<MD5::MD5Result> Checksum = None, 863 Optional<StringRef> Source = None, 864 unsigned CUID = 0) { 865 return cantFail( 866 tryEmitDwarfFileDirective(FileNo, Directory, Filename, Checksum, 867 Source, CUID)); 868 } 869 870 /// Associate a filename with a specified logical file number. 871 /// Also associate a directory, optional checksum, and optional source 872 /// text with the logical file. This implements the DWARF2 873 /// '.file 4 "dir/foo.c"' assembler directive, and the DWARF5 874 /// '.file 4 "dir/foo.c" md5 "..." source "..."' assembler directive. 875 virtual Expected<unsigned> tryEmitDwarfFileDirective( 876 unsigned FileNo, StringRef Directory, StringRef Filename, 877 Optional<MD5::MD5Result> Checksum = None, Optional<StringRef> Source = None, 878 unsigned CUID = 0); 879 880 /// Specify the "root" file of the compilation, using the ".file 0" extension. 881 virtual void emitDwarfFile0Directive(StringRef Directory, StringRef Filename, 882 Optional<MD5::MD5Result> Checksum, 883 Optional<StringRef> Source, 884 unsigned CUID = 0); 885 886 virtual void emitCFIBKeyFrame(); 887 888 /// This implements the DWARF2 '.loc fileno lineno ...' assembler 889 /// directive. 890 virtual void emitDwarfLocDirective(unsigned FileNo, unsigned Line, 891 unsigned Column, unsigned Flags, 892 unsigned Isa, unsigned Discriminator, 893 StringRef FileName); 894 895 /// Associate a filename with a specified logical file number, and also 896 /// specify that file's checksum information. This implements the '.cv_file 4 897 /// "foo.c"' assembler directive. Returns true on success. 898 virtual bool EmitCVFileDirective(unsigned FileNo, StringRef Filename, 899 ArrayRef<uint8_t> Checksum, 900 unsigned ChecksumKind); 901 902 /// Introduces a function id for use with .cv_loc. 903 virtual bool EmitCVFuncIdDirective(unsigned FunctionId); 904 905 /// Introduces an inline call site id for use with .cv_loc. Includes 906 /// extra information for inline line table generation. 907 virtual bool EmitCVInlineSiteIdDirective(unsigned FunctionId, unsigned IAFunc, 908 unsigned IAFile, unsigned IALine, 909 unsigned IACol, SMLoc Loc); 910 911 /// This implements the CodeView '.cv_loc' assembler directive. 912 virtual void emitCVLocDirective(unsigned FunctionId, unsigned FileNo, 913 unsigned Line, unsigned Column, 914 bool PrologueEnd, bool IsStmt, 915 StringRef FileName, SMLoc Loc); 916 917 /// This implements the CodeView '.cv_linetable' assembler directive. 918 virtual void emitCVLinetableDirective(unsigned FunctionId, 919 const MCSymbol *FnStart, 920 const MCSymbol *FnEnd); 921 922 /// This implements the CodeView '.cv_inline_linetable' assembler 923 /// directive. 924 virtual void emitCVInlineLinetableDirective(unsigned PrimaryFunctionId, 925 unsigned SourceFileId, 926 unsigned SourceLineNum, 927 const MCSymbol *FnStartSym, 928 const MCSymbol *FnEndSym); 929 930 /// This implements the CodeView '.cv_def_range' assembler 931 /// directive. 932 virtual void emitCVDefRangeDirective( 933 ArrayRef<std::pair<const MCSymbol *, const MCSymbol *>> Ranges, 934 StringRef FixedSizePortion); 935 936 virtual void emitCVDefRangeDirective( 937 ArrayRef<std::pair<const MCSymbol *, const MCSymbol *>> Ranges, 938 codeview::DefRangeRegisterRelHeader DRHdr); 939 940 virtual void emitCVDefRangeDirective( 941 ArrayRef<std::pair<const MCSymbol *, const MCSymbol *>> Ranges, 942 codeview::DefRangeSubfieldRegisterHeader DRHdr); 943 944 virtual void emitCVDefRangeDirective( 945 ArrayRef<std::pair<const MCSymbol *, const MCSymbol *>> Ranges, 946 codeview::DefRangeRegisterHeader DRHdr); 947 948 virtual void emitCVDefRangeDirective( 949 ArrayRef<std::pair<const MCSymbol *, const MCSymbol *>> Ranges, 950 codeview::DefRangeFramePointerRelHeader DRHdr); 951 952 /// This implements the CodeView '.cv_stringtable' assembler directive. emitCVStringTableDirective()953 virtual void emitCVStringTableDirective() {} 954 955 /// This implements the CodeView '.cv_filechecksums' assembler directive. emitCVFileChecksumsDirective()956 virtual void emitCVFileChecksumsDirective() {} 957 958 /// This implements the CodeView '.cv_filechecksumoffset' assembler 959 /// directive. emitCVFileChecksumOffsetDirective(unsigned FileNo)960 virtual void emitCVFileChecksumOffsetDirective(unsigned FileNo) {} 961 962 /// This implements the CodeView '.cv_fpo_data' assembler directive. 963 virtual void EmitCVFPOData(const MCSymbol *ProcSym, SMLoc Loc = {}) {} 964 965 /// Emit the absolute difference between two symbols. 966 /// 967 /// \pre Offset of \c Hi is greater than the offset \c Lo. 968 virtual void emitAbsoluteSymbolDiff(const MCSymbol *Hi, const MCSymbol *Lo, 969 unsigned Size); 970 971 /// Emit the absolute difference between two symbols encoded with ULEB128. 972 virtual void emitAbsoluteSymbolDiffAsULEB128(const MCSymbol *Hi, 973 const MCSymbol *Lo); 974 975 virtual MCSymbol *getDwarfLineTableSymbol(unsigned CUID); 976 virtual void emitCFISections(bool EH, bool Debug); 977 void emitCFIStartProc(bool IsSimple, SMLoc Loc = SMLoc()); 978 void emitCFIEndProc(); 979 virtual void emitCFIDefCfa(int64_t Register, int64_t Offset); 980 virtual void emitCFIDefCfaOffset(int64_t Offset); 981 virtual void emitCFIDefCfaRegister(int64_t Register); 982 virtual void emitCFIOffset(int64_t Register, int64_t Offset); 983 virtual void emitCFIPersonality(const MCSymbol *Sym, unsigned Encoding); 984 virtual void emitCFILsda(const MCSymbol *Sym, unsigned Encoding); 985 virtual void emitCFIRememberState(); 986 virtual void emitCFIRestoreState(); 987 virtual void emitCFISameValue(int64_t Register); 988 virtual void emitCFIRestore(int64_t Register); 989 virtual void emitCFIRelOffset(int64_t Register, int64_t Offset); 990 virtual void emitCFIAdjustCfaOffset(int64_t Adjustment); 991 virtual void emitCFIEscape(StringRef Values); 992 virtual void emitCFIReturnColumn(int64_t Register); 993 virtual void emitCFIGnuArgsSize(int64_t Size); 994 virtual void emitCFISignalFrame(); 995 virtual void emitCFIUndefined(int64_t Register); 996 virtual void emitCFIRegister(int64_t Register1, int64_t Register2); 997 virtual void emitCFIWindowSave(); 998 virtual void emitCFINegateRAState(); 999 1000 virtual void EmitWinCFIStartProc(const MCSymbol *Symbol, SMLoc Loc = SMLoc()); 1001 virtual void EmitWinCFIEndProc(SMLoc Loc = SMLoc()); 1002 /// This is used on platforms, such as Windows on ARM64, that require function 1003 /// or funclet sizes to be emitted in .xdata before the End marker is emitted 1004 /// for the frame. We cannot use the End marker, as it is not set at the 1005 /// point of emitting .xdata, in order to indicate that the frame is active. 1006 virtual void EmitWinCFIFuncletOrFuncEnd(SMLoc Loc = SMLoc()); 1007 virtual void EmitWinCFIStartChained(SMLoc Loc = SMLoc()); 1008 virtual void EmitWinCFIEndChained(SMLoc Loc = SMLoc()); 1009 virtual void EmitWinCFIPushReg(MCRegister Register, SMLoc Loc = SMLoc()); 1010 virtual void EmitWinCFISetFrame(MCRegister Register, unsigned Offset, 1011 SMLoc Loc = SMLoc()); 1012 virtual void EmitWinCFIAllocStack(unsigned Size, SMLoc Loc = SMLoc()); 1013 virtual void EmitWinCFISaveReg(MCRegister Register, unsigned Offset, 1014 SMLoc Loc = SMLoc()); 1015 virtual void EmitWinCFISaveXMM(MCRegister Register, unsigned Offset, 1016 SMLoc Loc = SMLoc()); 1017 virtual void EmitWinCFIPushFrame(bool Code, SMLoc Loc = SMLoc()); 1018 virtual void EmitWinCFIEndProlog(SMLoc Loc = SMLoc()); 1019 virtual void EmitWinEHHandler(const MCSymbol *Sym, bool Unwind, bool Except, 1020 SMLoc Loc = SMLoc()); 1021 virtual void EmitWinEHHandlerData(SMLoc Loc = SMLoc()); 1022 1023 virtual void emitCGProfileEntry(const MCSymbolRefExpr *From, 1024 const MCSymbolRefExpr *To, uint64_t Count); 1025 1026 /// Get the .pdata section used for the given section. Typically the given 1027 /// section is either the main .text section or some other COMDAT .text 1028 /// section, but it may be any section containing code. 1029 MCSection *getAssociatedPDataSection(const MCSection *TextSec); 1030 1031 /// Get the .xdata section used for the given section. 1032 MCSection *getAssociatedXDataSection(const MCSection *TextSec); 1033 1034 virtual void emitSyntaxDirective(); 1035 1036 /// Record a relocation described by the .reloc directive. Return None if 1037 /// succeeded. Otherwise, return a pair (Name is invalid, error message). 1038 virtual Optional<std::pair<bool, std::string>> emitRelocDirective(const MCExpr & Offset,StringRef Name,const MCExpr * Expr,SMLoc Loc,const MCSubtargetInfo & STI)1039 emitRelocDirective(const MCExpr &Offset, StringRef Name, const MCExpr *Expr, 1040 SMLoc Loc, const MCSubtargetInfo &STI) { 1041 return None; 1042 } 1043 emitAddrsig()1044 virtual void emitAddrsig() {} emitAddrsigSym(const MCSymbol * Sym)1045 virtual void emitAddrsigSym(const MCSymbol *Sym) {} 1046 1047 /// Emit the given \p Instruction into the current section. 1048 virtual void emitInstruction(const MCInst &Inst, const MCSubtargetInfo &STI); 1049 1050 /// Emit the a pseudo probe into the current section. 1051 virtual void emitPseudoProbe(uint64_t Guid, uint64_t Index, uint64_t Type, 1052 uint64_t Attr, 1053 const MCPseudoProbeInlineStack &InlineStack); 1054 1055 /// Set the bundle alignment mode from now on in the section. 1056 /// The argument is the power of 2 to which the alignment is set. The 1057 /// value 0 means turn the bundle alignment off. 1058 virtual void emitBundleAlignMode(unsigned AlignPow2); 1059 1060 /// The following instructions are a bundle-locked group. 1061 /// 1062 /// \param AlignToEnd - If true, the bundle-locked group will be aligned to 1063 /// the end of a bundle. 1064 virtual void emitBundleLock(bool AlignToEnd); 1065 1066 /// Ends a bundle-locked group. 1067 virtual void emitBundleUnlock(); 1068 1069 /// If this file is backed by a assembly streamer, this dumps the 1070 /// specified string in the output .s file. This capability is indicated by 1071 /// the hasRawTextSupport() predicate. By default this aborts. 1072 void emitRawText(const Twine &String); 1073 1074 /// Streamer specific finalization. 1075 virtual void finishImpl(); 1076 /// Finish emission of machine code. 1077 void Finish(SMLoc EndLoc = SMLoc()); 1078 mayHaveInstructions(MCSection & Sec)1079 virtual bool mayHaveInstructions(MCSection &Sec) const { return true; } 1080 1081 /// Emit a special value of 0xffffffff if producing 64-bit debugging info. 1082 void maybeEmitDwarf64Mark(); 1083 1084 /// Emit a unit length field. The actual format, DWARF32 or DWARF64, is chosen 1085 /// according to the settings. 1086 virtual void emitDwarfUnitLength(uint64_t Length, const Twine &Comment); 1087 1088 /// Emit a unit length field. The actual format, DWARF32 or DWARF64, is chosen 1089 /// according to the settings. 1090 /// Return the end symbol generated inside, the caller needs to emit it. 1091 virtual MCSymbol *emitDwarfUnitLength(const Twine &Prefix, 1092 const Twine &Comment); 1093 1094 /// Emit the debug line start label. 1095 virtual void emitDwarfLineStartLabel(MCSymbol *StartSym); 1096 1097 /// Emit the debug line end entry. emitDwarfLineEndEntry(MCSection * Section,MCSymbol * LastLabel)1098 virtual void emitDwarfLineEndEntry(MCSection *Section, MCSymbol *LastLabel) {} 1099 1100 /// If targets does not support representing debug line section by .loc/.file 1101 /// directives in assembly output, we need to populate debug line section with 1102 /// raw debug line contents. emitDwarfAdvanceLineAddr(int64_t LineDelta,const MCSymbol * LastLabel,const MCSymbol * Label,unsigned PointerSize)1103 virtual void emitDwarfAdvanceLineAddr(int64_t LineDelta, 1104 const MCSymbol *LastLabel, 1105 const MCSymbol *Label, 1106 unsigned PointerSize) {} 1107 1108 /// Do finalization for the streamer at the end of a section. doFinalizationAtSectionEnd(MCSection * Section)1109 virtual void doFinalizationAtSectionEnd(MCSection *Section) {} 1110 }; 1111 1112 /// Create a dummy machine code streamer, which does nothing. This is useful for 1113 /// timing the assembler front end. 1114 MCStreamer *createNullStreamer(MCContext &Ctx); 1115 1116 } // end namespace llvm 1117 1118 #endif // LLVM_MC_MCSTREAMER_H 1119