1 //===- MCStreamer.h - High-level Streaming Machine Code Output --*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file declares the MCStreamer class.
12 //===----------------------------------------------------------------------===//
14 #ifndef LLVM_MC_MCSTREAMER_H
15 #define LLVM_MC_MCSTREAMER_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/MCDwarf.h"
24 #include "llvm/MC/MCLinkerOptimizationHint.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"
40 class AssemblerConstantPools;
41 class formatted_raw_ostream;
44 struct MCCodePaddingContext;
51 class MCSymbolRefExpr;
52 class MCSubtargetInfo;
56 using MCSectionSubPair = std::pair<MCSection *, const MCExpr *>;
58 /// Target specific streamer interface. This is used so that targets can
59 /// implement support for target specific assembly directives.
61 /// If target foo wants to use this, it should implement 3 classes:
62 /// * FooTargetStreamer : public MCTargetStreamer
63 /// * FooTargetAsmStreamer : public FooTargetStreamer
64 /// * FooTargetELFStreamer : public FooTargetStreamer
66 /// FooTargetStreamer should have a pure virtual method for each directive. For
67 /// example, for a ".bar symbol_name" directive, it should have
68 /// virtual emitBar(const MCSymbol &Symbol) = 0;
70 /// The FooTargetAsmStreamer and FooTargetELFStreamer classes implement the
71 /// method. The assembly streamer just prints ".bar symbol_name". The object
72 /// streamer does whatever is needed to implement .bar in the object file.
74 /// In the assembly printer and parser the target streamer can be used by
75 /// calling getTargetStreamer and casting it to FooTargetStreamer:
77 /// MCTargetStreamer &TS = OutStreamer.getTargetStreamer();
78 /// FooTargetStreamer &ATS = static_cast<FooTargetStreamer &>(TS);
80 /// The base classes FooTargetAsmStreamer and FooTargetELFStreamer should
81 /// *never* be treated differently. Callers should always talk to a
82 /// FooTargetStreamer.
83 class MCTargetStreamer {
88 MCTargetStreamer(MCStreamer &S);
89 virtual ~MCTargetStreamer();
91 MCStreamer &getStreamer() { return Streamer; }
93 // Allow a target to add behavior to the EmitLabel of MCStreamer.
94 virtual void emitLabel(MCSymbol *Symbol);
95 // Allow a target to add behavior to the emitAssignment of MCStreamer.
96 virtual void emitAssignment(MCSymbol *Symbol, const MCExpr *Value);
98 virtual void prettyPrintAsm(MCInstPrinter &InstPrinter, raw_ostream &OS,
99 const MCInst &Inst, const MCSubtargetInfo &STI);
101 virtual void emitDwarfFileDirective(StringRef Directive);
103 /// Update streamer for a new active section.
105 /// This is called by PopSection and SwitchSection, if the current
107 virtual void changeSection(const MCSection *CurSection, MCSection *Section,
108 const MCExpr *SubSection, raw_ostream &OS);
110 virtual void emitValue(const MCExpr *Value);
112 virtual void finish();
115 // FIXME: declared here because it is used from
116 // lib/CodeGen/AsmPrinter/ARMException.cpp.
117 class ARMTargetStreamer : public MCTargetStreamer {
119 ARMTargetStreamer(MCStreamer &S);
120 ~ARMTargetStreamer() override;
122 virtual void emitFnStart();
123 virtual void emitFnEnd();
124 virtual void emitCantUnwind();
125 virtual void emitPersonality(const MCSymbol *Personality);
126 virtual void emitPersonalityIndex(unsigned Index);
127 virtual void emitHandlerData();
128 virtual void emitSetFP(unsigned FpReg, unsigned SpReg,
130 virtual void emitMovSP(unsigned Reg, int64_t Offset = 0);
131 virtual void emitPad(int64_t Offset);
132 virtual void emitRegSave(const SmallVectorImpl<unsigned> &RegList,
134 virtual void emitUnwindRaw(int64_t StackOffset,
135 const SmallVectorImpl<uint8_t> &Opcodes);
137 virtual void switchVendor(StringRef Vendor);
138 virtual void emitAttribute(unsigned Attribute, unsigned Value);
139 virtual void emitTextAttribute(unsigned Attribute, StringRef String);
140 virtual void emitIntTextAttribute(unsigned Attribute, unsigned IntValue,
141 StringRef StringValue = "");
142 virtual void emitFPU(unsigned FPU);
143 virtual void emitArch(ARM::ArchKind Arch);
144 virtual void emitArchExtension(unsigned ArchExt);
145 virtual void emitObjectArch(ARM::ArchKind Arch);
146 void emitTargetAttributes(const MCSubtargetInfo &STI);
147 virtual void finishAttributeSection();
148 virtual void emitInst(uint32_t Inst, char Suffix = '\0');
150 virtual void AnnotateTLSDescriptorSequence(const MCSymbolRefExpr *SRE);
152 virtual void emitThumbSet(MCSymbol *Symbol, const MCExpr *Value);
154 void finish() override;
156 /// Reset any state between object emissions, i.e. the equivalent of
157 /// MCStreamer's reset method.
158 virtual void reset();
160 /// Callback used to implement the ldr= pseudo.
161 /// Add a new entry to the constant pool for the current section and return an
162 /// MCExpr that can be used to refer to the constant pool location.
163 const MCExpr *addConstantPoolEntry(const MCExpr *, SMLoc Loc);
165 /// Callback used to implemnt the .ltorg directive.
166 /// Emit contents of constant pool for the current section.
167 void emitCurrentConstantPool();
170 std::unique_ptr<AssemblerConstantPools> ConstantPools;
173 /// Streaming machine code generation interface.
175 /// This interface is intended to provide a programatic interface that is very
176 /// similar to the level that an assembler .s file provides. It has callbacks
177 /// to emit bytes, handle directives, etc. The implementation of this interface
178 /// retains state to know what the current section is etc.
180 /// There are multiple implementations of this interface: one for writing out
181 /// a .s file, and implementations that write out .o files of various formats.
185 std::unique_ptr<MCTargetStreamer> TargetStreamer;
187 std::vector<MCDwarfFrameInfo> DwarfFrameInfos;
188 MCDwarfFrameInfo *getCurrentDwarfFrameInfo();
190 /// Similar to DwarfFrameInfos, but for SEH unwind info. Chained frames may
191 /// refer to each other, so use std::unique_ptr to provide pointer stability.
192 std::vector<std::unique_ptr<WinEH::FrameInfo>> WinFrameInfos;
194 WinEH::FrameInfo *CurrentWinFrameInfo;
196 /// Retreive the current frame info if one is available and it is not yet
197 /// closed. Otherwise, issue an error and return null.
198 WinEH::FrameInfo *EnsureValidWinFrameInfo(SMLoc Loc);
200 /// Tracks an index to represent the order a symbol was emitted in.
201 /// Zero means we did not emit that symbol.
202 DenseMap<const MCSymbol *, unsigned> SymbolOrdering;
204 /// This is stack of current and previous section values saved by
206 SmallVector<std::pair<MCSectionSubPair, MCSectionSubPair>, 4> SectionStack;
208 /// The next unique ID to use when creating a WinCFI-related section (.pdata
209 /// or .xdata). This ID ensures that we have a one-to-one mapping from
210 /// code section to unwind info section, which MSVC's incremental linker
212 unsigned NextWinCFIID = 0;
214 bool UseAssemblerInfoForParsing;
217 MCStreamer(MCContext &Ctx);
219 virtual void EmitCFIStartProcImpl(MCDwarfFrameInfo &Frame);
220 virtual void EmitCFIEndProcImpl(MCDwarfFrameInfo &CurFrame);
222 /// When emitting an object file, create and emit a real label. When emitting
223 /// textual assembly, this should do nothing to avoid polluting our output.
224 virtual MCSymbol *EmitCFILabel();
226 WinEH::FrameInfo *getCurrentWinFrameInfo() {
227 return CurrentWinFrameInfo;
230 virtual void EmitWindowsUnwindTables();
232 virtual void EmitRawTextImpl(StringRef String);
235 MCStreamer(const MCStreamer &) = delete;
236 MCStreamer &operator=(const MCStreamer &) = delete;
237 virtual ~MCStreamer();
239 void visitUsedExpr(const MCExpr &Expr);
240 virtual void visitUsedSymbol(const MCSymbol &Sym);
242 void setTargetStreamer(MCTargetStreamer *TS) {
243 TargetStreamer.reset(TS);
248 virtual void reset();
250 MCContext &getContext() const { return Context; }
252 virtual MCAssembler *getAssemblerPtr() { return nullptr; }
254 void setUseAssemblerInfoForParsing(bool v) { UseAssemblerInfoForParsing = v; }
255 bool getUseAssemblerInfoForParsing() { return UseAssemblerInfoForParsing; }
257 MCTargetStreamer *getTargetStreamer() {
258 return TargetStreamer.get();
261 unsigned getNumFrameInfos() { return DwarfFrameInfos.size(); }
262 ArrayRef<MCDwarfFrameInfo> getDwarfFrameInfos() const {
263 return DwarfFrameInfos;
266 bool hasUnfinishedDwarfFrameInfo();
268 unsigned getNumWinFrameInfos() { return WinFrameInfos.size(); }
269 ArrayRef<std::unique_ptr<WinEH::FrameInfo>> getWinFrameInfos() const {
270 return WinFrameInfos;
273 void generateCompactUnwindEncodings(MCAsmBackend *MAB);
275 /// \name Assembly File Formatting.
278 /// Return true if this streamer supports verbose assembly and if it is
280 virtual bool isVerboseAsm() const { return false; }
282 /// Return true if this asm streamer supports emitting unformatted text
283 /// to the .s file with EmitRawText.
284 virtual bool hasRawTextSupport() const { return false; }
286 /// Is the integrated assembler required for this streamer to function
288 virtual bool isIntegratedAssemblerRequired() const { return false; }
290 /// Add a textual comment.
292 /// Typically for comments that can be emitted to the generated .s
293 /// file if applicable as a QoI issue to make the output of the compiler
294 /// more readable. This only affects the MCAsmStreamer, and only when
295 /// verbose assembly output is enabled.
297 /// If the comment includes embedded \n's, they will each get the comment
298 /// prefix as appropriate. The added comment should not end with a \n.
299 /// By default, each comment is terminated with an end of line, i.e. the
300 /// EOL param is set to true by default. If one prefers not to end the
301 /// comment with a new line then the EOL param should be passed
302 /// with a false value.
303 virtual void AddComment(const Twine &T, bool EOL = true) {}
305 /// Return a raw_ostream that comments can be written to. Unlike
306 /// AddComment, you are required to terminate comments with \n if you use this
308 virtual raw_ostream &GetCommentOS();
310 /// Print T and prefix it with the comment string (normally #) and
311 /// optionally a tab. This prints the comment immediately, not at the end of
312 /// the current line. It is basically a safe version of EmitRawText: since it
313 /// only prints comments, the object streamer ignores it instead of asserting.
314 virtual void emitRawComment(const Twine &T, bool TabPrefix = true);
316 /// Add explicit comment T. T is required to be a valid
317 /// comment in the output and does not need to be escaped.
318 virtual void addExplicitComment(const Twine &T);
320 /// Emit added explicit comments.
321 virtual void emitExplicitComments();
323 /// AddBlankLine - Emit a blank line to a .s file to pretty it up.
324 virtual void AddBlankLine() {}
328 /// \name Symbol & Section Management
331 /// Return the current section that the streamer is emitting code to.
332 MCSectionSubPair getCurrentSection() const {
333 if (!SectionStack.empty())
334 return SectionStack.back().first;
335 return MCSectionSubPair();
337 MCSection *getCurrentSectionOnly() const { return getCurrentSection().first; }
339 /// Return the previous section that the streamer is emitting code to.
340 MCSectionSubPair getPreviousSection() const {
341 if (!SectionStack.empty())
342 return SectionStack.back().second;
343 return MCSectionSubPair();
346 /// Returns an index to represent the order a symbol was emitted in.
347 /// (zero if we did not emit that symbol)
348 unsigned GetSymbolOrder(const MCSymbol *Sym) const {
349 return SymbolOrdering.lookup(Sym);
352 /// Update streamer for a new active section.
354 /// This is called by PopSection and SwitchSection, if the current
356 virtual void ChangeSection(MCSection *, const MCExpr *);
358 /// Save the current and previous section on the section stack.
360 SectionStack.push_back(
361 std::make_pair(getCurrentSection(), getPreviousSection()));
364 /// Restore the current and previous section from the section stack.
365 /// Calls ChangeSection as needed.
367 /// Returns false if the stack was empty.
369 if (SectionStack.size() <= 1)
371 auto I = SectionStack.end();
373 MCSectionSubPair OldSection = I->first;
375 MCSectionSubPair NewSection = I->first;
377 if (OldSection != NewSection)
378 ChangeSection(NewSection.first, NewSection.second);
379 SectionStack.pop_back();
383 bool SubSection(const MCExpr *Subsection) {
384 if (SectionStack.empty())
387 SwitchSection(SectionStack.back().first.first, Subsection);
391 /// Set the current section where code is being emitted to \p Section. This
392 /// is required to update CurSection.
394 /// This corresponds to assembler directives like .section, .text, etc.
395 virtual void SwitchSection(MCSection *Section,
396 const MCExpr *Subsection = nullptr);
398 /// Set the current section where code is being emitted to \p Section.
399 /// This is required to update CurSection. This version does not call
401 void SwitchSectionNoChange(MCSection *Section,
402 const MCExpr *Subsection = nullptr) {
403 assert(Section && "Cannot switch to a null section!");
404 MCSectionSubPair curSection = SectionStack.back().first;
405 SectionStack.back().second = curSection;
406 if (MCSectionSubPair(Section, Subsection) != curSection)
407 SectionStack.back().first = MCSectionSubPair(Section, Subsection);
410 /// Create the default sections and set the initial one.
411 virtual void InitSections(bool NoExecStack);
413 MCSymbol *endSection(MCSection *Section);
415 /// Sets the symbol's section.
417 /// Each emitted symbol will be tracked in the ordering table,
418 /// so we can sort on them later.
419 void AssignFragment(MCSymbol *Symbol, MCFragment *Fragment);
421 /// Emit a label for \p Symbol into the current section.
423 /// This corresponds to an assembler statement such as:
426 /// \param Symbol - The symbol to emit. A given symbol should only be
427 /// emitted as a label once, and symbols emitted as a label should never be
428 /// used in an assignment.
429 // FIXME: These emission are non-const because we mutate the symbol to
430 // add the section we're emitting it to later.
431 virtual void EmitLabel(MCSymbol *Symbol, SMLoc Loc = SMLoc());
433 virtual void EmitEHSymAttributes(const MCSymbol *Symbol, MCSymbol *EHSymbol);
435 /// Note in the output the specified \p Flag.
436 virtual void EmitAssemblerFlag(MCAssemblerFlag Flag);
438 /// Emit the given list \p Options of strings as linker
439 /// options into the output.
440 virtual void EmitLinkerOptions(ArrayRef<std::string> Kind) {}
442 /// Note in the output the specified region \p Kind.
443 virtual void EmitDataRegion(MCDataRegionType Kind) {}
445 /// Specify the Mach-O minimum deployment target version.
446 virtual void EmitVersionMin(MCVersionMinType Type, unsigned Major,
447 unsigned Minor, unsigned Update) {}
449 /// Emit/Specify Mach-O build version command.
450 /// \p Platform should be one of MachO::PlatformType.
451 virtual void EmitBuildVersion(unsigned Platform, unsigned Major,
452 unsigned Minor, unsigned Update) {}
454 void EmitVersionForTarget(const Triple &Target);
456 /// Note in the output that the specified \p Func is a Thumb mode
457 /// function (ARM target only).
458 virtual void EmitThumbFunc(MCSymbol *Func);
460 /// Emit an assignment of \p Value to \p Symbol.
462 /// This corresponds to an assembler statement such as:
465 /// The assignment generates no code, but has the side effect of binding the
466 /// value in the current context. For the assembly streamer, this prints the
467 /// binding into the .s file.
469 /// \param Symbol - The symbol being assigned to.
470 /// \param Value - The value for the symbol.
471 virtual void EmitAssignment(MCSymbol *Symbol, const MCExpr *Value);
473 /// Emit an weak reference from \p Alias to \p Symbol.
475 /// This corresponds to an assembler statement such as:
476 /// .weakref alias, symbol
478 /// \param Alias - The alias that is being created.
479 /// \param Symbol - The symbol being aliased.
480 virtual void EmitWeakReference(MCSymbol *Alias, const MCSymbol *Symbol);
482 /// Add the given \p Attribute to \p Symbol.
483 virtual bool EmitSymbolAttribute(MCSymbol *Symbol,
484 MCSymbolAttr Attribute) = 0;
486 /// Set the \p DescValue for the \p Symbol.
488 /// \param Symbol - The symbol to have its n_desc field set.
489 /// \param DescValue - The value to set into the n_desc field.
490 virtual void EmitSymbolDesc(MCSymbol *Symbol, unsigned DescValue);
492 /// Start emitting COFF symbol definition
494 /// \param Symbol - The symbol to have its External & Type fields set.
495 virtual void BeginCOFFSymbolDef(const MCSymbol *Symbol);
497 /// Emit the storage class of the symbol.
499 /// \param StorageClass - The storage class the symbol should have.
500 virtual void EmitCOFFSymbolStorageClass(int StorageClass);
502 /// Emit the type of the symbol.
504 /// \param Type - A COFF type identifier (see COFF::SymbolType in X86COFF.h)
505 virtual void EmitCOFFSymbolType(int Type);
507 /// Marks the end of the symbol definition.
508 virtual void EndCOFFSymbolDef();
510 virtual void EmitCOFFSafeSEH(MCSymbol const *Symbol);
512 /// Emits the symbol table index of a Symbol into the current section.
513 virtual void EmitCOFFSymbolIndex(MCSymbol const *Symbol);
515 /// Emits a COFF section index.
517 /// \param Symbol - Symbol the section number relocation should point to.
518 virtual void EmitCOFFSectionIndex(MCSymbol const *Symbol);
520 /// Emits a COFF section relative relocation.
522 /// \param Symbol - Symbol the section relative relocation should point to.
523 virtual void EmitCOFFSecRel32(MCSymbol const *Symbol, uint64_t Offset);
525 /// Emits a COFF image relative relocation.
527 /// \param Symbol - Symbol the image relative relocation should point to.
528 virtual void EmitCOFFImgRel32(MCSymbol const *Symbol, int64_t Offset);
530 /// Emit an ELF .size directive.
532 /// This corresponds to an assembler statement such as:
533 /// .size symbol, expression
534 virtual void emitELFSize(MCSymbol *Symbol, const MCExpr *Value);
536 /// Emit an ELF .symver directive.
538 /// This corresponds to an assembler statement such as:
539 /// .symver _start, foo@@SOME_VERSION
540 /// \param AliasName - The versioned alias (i.e. "foo@@SOME_VERSION")
541 /// \param Aliasee - The aliased symbol (i.e. "_start")
542 virtual void emitELFSymverDirective(StringRef AliasName,
543 const MCSymbol *Aliasee);
545 /// Emit a Linker Optimization Hint (LOH) directive.
546 /// \param Args - Arguments of the LOH.
547 virtual void EmitLOHDirective(MCLOHType Kind, const MCLOHArgs &Args) {}
549 /// Emit a common symbol.
551 /// \param Symbol - The common symbol to emit.
552 /// \param Size - The size of the common symbol.
553 /// \param ByteAlignment - The alignment of the symbol if
554 /// non-zero. This must be a power of 2.
555 virtual void EmitCommonSymbol(MCSymbol *Symbol, uint64_t Size,
556 unsigned ByteAlignment) = 0;
558 /// Emit a local common (.lcomm) symbol.
560 /// \param Symbol - The common symbol to emit.
561 /// \param Size - The size of the common symbol.
562 /// \param ByteAlignment - The alignment of the common symbol in bytes.
563 virtual void EmitLocalCommonSymbol(MCSymbol *Symbol, uint64_t Size,
564 unsigned ByteAlignment);
566 /// Emit the zerofill section and an optional symbol.
568 /// \param Section - The zerofill section to create and or to put the symbol
569 /// \param Symbol - The zerofill symbol to emit, if non-NULL.
570 /// \param Size - The size of the zerofill symbol.
571 /// \param ByteAlignment - The alignment of the zerofill symbol if
572 /// non-zero. This must be a power of 2 on some targets.
573 virtual void EmitZerofill(MCSection *Section, MCSymbol *Symbol = nullptr,
574 uint64_t Size = 0, unsigned ByteAlignment = 0,
575 SMLoc Loc = SMLoc()) = 0;
577 /// Emit a thread local bss (.tbss) symbol.
579 /// \param Section - The thread local common section.
580 /// \param Symbol - The thread local common symbol to emit.
581 /// \param Size - The size of the symbol.
582 /// \param ByteAlignment - The alignment of the thread local common symbol
583 /// if non-zero. This must be a power of 2 on some targets.
584 virtual void EmitTBSSSymbol(MCSection *Section, MCSymbol *Symbol,
585 uint64_t Size, unsigned ByteAlignment = 0);
588 /// \name Generating Data
591 /// Emit the bytes in \p Data into the output.
593 /// This is used to implement assembler directives such as .byte, .ascii,
595 virtual void EmitBytes(StringRef Data);
597 /// Functionally identical to EmitBytes. When emitting textual assembly, this
598 /// method uses .byte directives instead of .ascii or .asciz for readability.
599 virtual void EmitBinaryData(StringRef Data);
601 /// Emit the expression \p Value into the output as a native
602 /// integer of the given \p Size bytes.
604 /// This is used to implement assembler directives such as .word, .quad,
607 /// \param Value - The value to emit.
608 /// \param Size - The size of the integer (in bytes) to emit. This must
609 /// match a native machine width.
610 /// \param Loc - The location of the expression for error reporting.
611 virtual void EmitValueImpl(const MCExpr *Value, unsigned Size,
612 SMLoc Loc = SMLoc());
614 void EmitValue(const MCExpr *Value, unsigned Size, SMLoc Loc = SMLoc());
616 /// Special case of EmitValue that avoids the client having
617 /// to pass in a MCExpr for constant integers.
618 virtual void EmitIntValue(uint64_t Value, unsigned Size);
620 virtual void EmitULEB128Value(const MCExpr *Value);
622 virtual void EmitSLEB128Value(const MCExpr *Value);
624 /// Special case of EmitULEB128Value that avoids the client having to
625 /// pass in a MCExpr for constant integers.
626 void EmitULEB128IntValue(uint64_t Value);
628 /// Special case of EmitSLEB128Value that avoids the client having to
629 /// pass in a MCExpr for constant integers.
630 void EmitSLEB128IntValue(int64_t Value);
632 /// Special case of EmitValue that avoids the client having to pass in
633 /// a MCExpr for MCSymbols.
634 void EmitSymbolValue(const MCSymbol *Sym, unsigned Size,
635 bool IsSectionRelative = false);
637 /// Emit the expression \p Value into the output as a dtprel
638 /// (64-bit DTP relative) value.
640 /// This is used to implement assembler directives such as .dtpreldword on
641 /// targets that support them.
642 virtual void EmitDTPRel64Value(const MCExpr *Value);
644 /// Emit the expression \p Value into the output as a dtprel
645 /// (32-bit DTP relative) value.
647 /// This is used to implement assembler directives such as .dtprelword on
648 /// targets that support them.
649 virtual void EmitDTPRel32Value(const MCExpr *Value);
651 /// Emit the expression \p Value into the output as a tprel
652 /// (64-bit TP relative) value.
654 /// This is used to implement assembler directives such as .tpreldword on
655 /// targets that support them.
656 virtual void EmitTPRel64Value(const MCExpr *Value);
658 /// Emit the expression \p Value into the output as a tprel
659 /// (32-bit TP relative) value.
661 /// This is used to implement assembler directives such as .tprelword on
662 /// targets that support them.
663 virtual void EmitTPRel32Value(const MCExpr *Value);
665 /// Emit the expression \p Value into the output as a gprel64 (64-bit
666 /// GP relative) value.
668 /// This is used to implement assembler directives such as .gpdword on
669 /// targets that support them.
670 virtual void EmitGPRel64Value(const MCExpr *Value);
672 /// Emit the expression \p Value into the output as a gprel32 (32-bit
673 /// GP relative) value.
675 /// This is used to implement assembler directives such as .gprel32 on
676 /// targets that support them.
677 virtual void EmitGPRel32Value(const MCExpr *Value);
679 /// Emit NumBytes bytes worth of the value specified by FillValue.
680 /// This implements directives such as '.space'.
681 void emitFill(uint64_t NumBytes, uint8_t FillValue);
683 /// Emit \p Size bytes worth of the value specified by \p FillValue.
685 /// This is used to implement assembler directives such as .space or .skip.
687 /// \param NumBytes - The number of bytes to emit.
688 /// \param FillValue - The value to use when filling bytes.
689 /// \param Loc - The location of the expression for error reporting.
690 virtual void emitFill(const MCExpr &NumBytes, uint64_t FillValue,
691 SMLoc Loc = SMLoc());
693 /// Emit \p NumValues copies of \p Size bytes. Each \p Size bytes is
694 /// taken from the lowest order 4 bytes of \p Expr expression.
696 /// This is used to implement assembler directives such as .fill.
698 /// \param NumValues - The number of copies of \p Size bytes to emit.
699 /// \param Size - The size (in bytes) of each repeated value.
700 /// \param Expr - The expression from which \p Size bytes are used.
701 virtual void emitFill(const MCExpr &NumValues, int64_t Size, int64_t Expr,
702 SMLoc Loc = SMLoc());
704 /// Emit NumBytes worth of zeros.
705 /// This function properly handles data in virtual sections.
706 void EmitZeros(uint64_t NumBytes);
708 /// Emit some number of copies of \p Value until the byte alignment \p
709 /// ByteAlignment is reached.
711 /// If the number of bytes need to emit for the alignment is not a multiple
712 /// of \p ValueSize, then the contents of the emitted fill bytes is
715 /// This used to implement the .align assembler directive.
717 /// \param ByteAlignment - The alignment to reach. This must be a power of
718 /// two on some targets.
719 /// \param Value - The value to use when filling bytes.
720 /// \param ValueSize - The size of the integer (in bytes) to emit for
721 /// \p Value. This must match a native machine width.
722 /// \param MaxBytesToEmit - The maximum numbers of bytes to emit, or 0. If
723 /// the alignment cannot be reached in this many bytes, no bytes are
725 virtual void EmitValueToAlignment(unsigned ByteAlignment, int64_t Value = 0,
726 unsigned ValueSize = 1,
727 unsigned MaxBytesToEmit = 0);
729 /// Emit nops until the byte alignment \p ByteAlignment is reached.
731 /// This used to align code where the alignment bytes may be executed. This
732 /// can emit different bytes for different sizes to optimize execution.
734 /// \param ByteAlignment - The alignment to reach. This must be a power of
735 /// two on some targets.
736 /// \param MaxBytesToEmit - The maximum numbers of bytes to emit, or 0. If
737 /// the alignment cannot be reached in this many bytes, no bytes are
739 virtual void EmitCodeAlignment(unsigned ByteAlignment,
740 unsigned MaxBytesToEmit = 0);
742 /// Emit some number of copies of \p Value until the byte offset \p
743 /// Offset is reached.
745 /// This is used to implement assembler directives such as .org.
747 /// \param Offset - The offset to reach. This may be an expression, but the
748 /// expression must be associated with the current section.
749 /// \param Value - The value to use when filling bytes.
750 virtual void emitValueToOffset(const MCExpr *Offset, unsigned char Value,
754 EmitCodePaddingBasicBlockStart(const MCCodePaddingContext &Context) {}
757 EmitCodePaddingBasicBlockEnd(const MCCodePaddingContext &Context) {}
761 /// Switch to a new logical file. This is used to implement the '.file
762 /// "foo.c"' assembler directive.
763 virtual void EmitFileDirective(StringRef Filename);
765 /// Emit the "identifiers" directive. This implements the
766 /// '.ident "version foo"' assembler directive.
767 virtual void EmitIdent(StringRef IdentString) {}
769 /// Associate a filename with a specified logical file number. This
770 /// implements the DWARF2 '.file 4 "foo.c"' assembler directive.
771 unsigned EmitDwarfFileDirective(unsigned FileNo, StringRef Directory,
773 MD5::MD5Result *Checksum = nullptr,
774 Optional<StringRef> Source = None,
777 tryEmitDwarfFileDirective(FileNo, Directory, Filename, Checksum,
781 /// Associate a filename with a specified logical file number.
782 /// Also associate a directory, optional checksum, and optional source
783 /// text with the logical file. This implements the DWARF2
784 /// '.file 4 "dir/foo.c"' assembler directive, and the DWARF5
785 /// '.file 4 "dir/foo.c" md5 "..." source "..."' assembler directive.
786 virtual Expected<unsigned> tryEmitDwarfFileDirective(
787 unsigned FileNo, StringRef Directory, StringRef Filename,
788 MD5::MD5Result *Checksum = nullptr, Optional<StringRef> Source = None,
791 /// Specify the "root" file of the compilation, using the ".file 0" extension.
792 virtual void emitDwarfFile0Directive(StringRef Directory, StringRef Filename,
793 MD5::MD5Result *Checksum,
794 Optional<StringRef> Source,
797 /// This implements the DWARF2 '.loc fileno lineno ...' assembler
799 virtual void EmitDwarfLocDirective(unsigned FileNo, unsigned Line,
800 unsigned Column, unsigned Flags,
801 unsigned Isa, unsigned Discriminator,
804 /// Associate a filename with a specified logical file number, and also
805 /// specify that file's checksum information. This implements the '.cv_file 4
806 /// "foo.c"' assembler directive. Returns true on success.
807 virtual bool EmitCVFileDirective(unsigned FileNo, StringRef Filename,
808 ArrayRef<uint8_t> Checksum,
809 unsigned ChecksumKind);
811 /// Introduces a function id for use with .cv_loc.
812 virtual bool EmitCVFuncIdDirective(unsigned FunctionId);
814 /// Introduces an inline call site id for use with .cv_loc. Includes
815 /// extra information for inline line table generation.
816 virtual bool EmitCVInlineSiteIdDirective(unsigned FunctionId, unsigned IAFunc,
817 unsigned IAFile, unsigned IALine,
818 unsigned IACol, SMLoc Loc);
820 /// This implements the CodeView '.cv_loc' assembler directive.
821 virtual void EmitCVLocDirective(unsigned FunctionId, unsigned FileNo,
822 unsigned Line, unsigned Column,
823 bool PrologueEnd, bool IsStmt,
824 StringRef FileName, SMLoc Loc);
826 /// This implements the CodeView '.cv_linetable' assembler directive.
827 virtual void EmitCVLinetableDirective(unsigned FunctionId,
828 const MCSymbol *FnStart,
829 const MCSymbol *FnEnd);
831 /// This implements the CodeView '.cv_inline_linetable' assembler
833 virtual void EmitCVInlineLinetableDirective(unsigned PrimaryFunctionId,
834 unsigned SourceFileId,
835 unsigned SourceLineNum,
836 const MCSymbol *FnStartSym,
837 const MCSymbol *FnEndSym);
839 /// This implements the CodeView '.cv_def_range' assembler
841 virtual void EmitCVDefRangeDirective(
842 ArrayRef<std::pair<const MCSymbol *, const MCSymbol *>> Ranges,
843 StringRef FixedSizePortion);
845 /// This implements the CodeView '.cv_stringtable' assembler directive.
846 virtual void EmitCVStringTableDirective() {}
848 /// This implements the CodeView '.cv_filechecksums' assembler directive.
849 virtual void EmitCVFileChecksumsDirective() {}
851 /// This implements the CodeView '.cv_filechecksumoffset' assembler
853 virtual void EmitCVFileChecksumOffsetDirective(unsigned FileNo) {}
855 /// This implements the CodeView '.cv_fpo_data' assembler directive.
856 virtual void EmitCVFPOData(const MCSymbol *ProcSym, SMLoc Loc = {}) {}
858 /// Emit the absolute difference between two symbols.
860 /// \pre Offset of \c Hi is greater than the offset \c Lo.
861 virtual void emitAbsoluteSymbolDiff(const MCSymbol *Hi, const MCSymbol *Lo,
864 /// Emit the absolute difference between two symbols encoded with ULEB128.
865 virtual void emitAbsoluteSymbolDiffAsULEB128(const MCSymbol *Hi,
868 virtual MCSymbol *getDwarfLineTableSymbol(unsigned CUID);
869 virtual void EmitCFISections(bool EH, bool Debug);
870 void EmitCFIStartProc(bool IsSimple);
871 void EmitCFIEndProc();
872 virtual void EmitCFIDefCfa(int64_t Register, int64_t Offset);
873 virtual void EmitCFIDefCfaOffset(int64_t Offset);
874 virtual void EmitCFIDefCfaRegister(int64_t Register);
875 virtual void EmitCFIOffset(int64_t Register, int64_t Offset);
876 virtual void EmitCFIPersonality(const MCSymbol *Sym, unsigned Encoding);
877 virtual void EmitCFILsda(const MCSymbol *Sym, unsigned Encoding);
878 virtual void EmitCFIRememberState();
879 virtual void EmitCFIRestoreState();
880 virtual void EmitCFISameValue(int64_t Register);
881 virtual void EmitCFIRestore(int64_t Register);
882 virtual void EmitCFIRelOffset(int64_t Register, int64_t Offset);
883 virtual void EmitCFIAdjustCfaOffset(int64_t Adjustment);
884 virtual void EmitCFIEscape(StringRef Values);
885 virtual void EmitCFIReturnColumn(int64_t Register);
886 virtual void EmitCFIGnuArgsSize(int64_t Size);
887 virtual void EmitCFISignalFrame();
888 virtual void EmitCFIUndefined(int64_t Register);
889 virtual void EmitCFIRegister(int64_t Register1, int64_t Register2);
890 virtual void EmitCFIWindowSave();
892 virtual void EmitWinCFIStartProc(const MCSymbol *Symbol, SMLoc Loc = SMLoc());
893 virtual void EmitWinCFIEndProc(SMLoc Loc = SMLoc());
894 virtual void EmitWinCFIStartChained(SMLoc Loc = SMLoc());
895 virtual void EmitWinCFIEndChained(SMLoc Loc = SMLoc());
896 virtual void EmitWinCFIPushReg(unsigned Register, SMLoc Loc = SMLoc());
897 virtual void EmitWinCFISetFrame(unsigned Register, unsigned Offset,
898 SMLoc Loc = SMLoc());
899 virtual void EmitWinCFIAllocStack(unsigned Size, SMLoc Loc = SMLoc());
900 virtual void EmitWinCFISaveReg(unsigned Register, unsigned Offset,
901 SMLoc Loc = SMLoc());
902 virtual void EmitWinCFISaveXMM(unsigned Register, unsigned Offset,
903 SMLoc Loc = SMLoc());
904 virtual void EmitWinCFIPushFrame(bool Code, SMLoc Loc = SMLoc());
905 virtual void EmitWinCFIEndProlog(SMLoc Loc = SMLoc());
906 virtual void EmitWinEHHandler(const MCSymbol *Sym, bool Unwind, bool Except,
907 SMLoc Loc = SMLoc());
908 virtual void EmitWinEHHandlerData(SMLoc Loc = SMLoc());
910 virtual void emitCGProfileEntry(const MCSymbolRefExpr *From,
911 const MCSymbolRefExpr *To, uint64_t Count);
913 /// Get the .pdata section used for the given section. Typically the given
914 /// section is either the main .text section or some other COMDAT .text
915 /// section, but it may be any section containing code.
916 MCSection *getAssociatedPDataSection(const MCSection *TextSec);
918 /// Get the .xdata section used for the given section.
919 MCSection *getAssociatedXDataSection(const MCSection *TextSec);
921 virtual void EmitSyntaxDirective();
923 /// Emit a .reloc directive.
924 /// Returns true if the relocation could not be emitted because Name is not
926 virtual bool EmitRelocDirective(const MCExpr &Offset, StringRef Name,
927 const MCExpr *Expr, SMLoc Loc,
928 const MCSubtargetInfo &STI) {
932 virtual void EmitAddrsig() {}
933 virtual void EmitAddrsigSym(const MCSymbol *Sym) {}
935 /// Emit the given \p Instruction into the current section.
936 /// PrintSchedInfo == true then schedul comment should be added to output
937 virtual void EmitInstruction(const MCInst &Inst, const MCSubtargetInfo &STI,
938 bool PrintSchedInfo = false);
940 /// Set the bundle alignment mode from now on in the section.
941 /// The argument is the power of 2 to which the alignment is set. The
942 /// value 0 means turn the bundle alignment off.
943 virtual void EmitBundleAlignMode(unsigned AlignPow2);
945 /// The following instructions are a bundle-locked group.
947 /// \param AlignToEnd - If true, the bundle-locked group will be aligned to
948 /// the end of a bundle.
949 virtual void EmitBundleLock(bool AlignToEnd);
951 /// Ends a bundle-locked group.
952 virtual void EmitBundleUnlock();
954 /// If this file is backed by a assembly streamer, this dumps the
955 /// specified string in the output .s file. This capability is indicated by
956 /// the hasRawTextSupport() predicate. By default this aborts.
957 void EmitRawText(const Twine &String);
959 /// Streamer specific finalization.
960 virtual void FinishImpl();
961 /// Finish emission of machine code.
964 virtual bool mayHaveInstructions(MCSection &Sec) const { return true; }
967 /// Create a dummy machine code streamer, which does nothing. This is useful for
968 /// timing the assembler front end.
969 MCStreamer *createNullStreamer(MCContext &Ctx);
971 /// Create a machine code streamer which will print out assembly for the native
972 /// target, suitable for compiling with a native assembler.
974 /// \param InstPrint - If given, the instruction printer to use. If not given
975 /// the MCInst representation will be printed. This method takes ownership of
978 /// \param CE - If given, a code emitter to use to show the instruction
979 /// encoding inline with the assembly. This method takes ownership of \p CE.
981 /// \param TAB - If given, a target asm backend to use to show the fixup
982 /// information in conjunction with encoding information. This method takes
983 /// ownership of \p TAB.
985 /// \param ShowInst - Whether to show the MCInst representation inline with
987 MCStreamer *createAsmStreamer(MCContext &Ctx,
988 std::unique_ptr<formatted_raw_ostream> OS,
989 bool isVerboseAsm, bool useDwarfDirectory,
990 MCInstPrinter *InstPrint, MCCodeEmitter *CE,
991 MCAsmBackend *TAB, bool ShowInst);
993 } // end namespace llvm
995 #endif // LLVM_MC_MCSTREAMER_H