1 //===-- AsmPrinter.cpp - Common AsmPrinter code ---------------------------===//
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 implements the AsmPrinter class.
12 //===----------------------------------------------------------------------===//
14 #include "llvm/CodeGen/AsmPrinter.h"
15 #include "DwarfDebug.h"
16 #include "DwarfException.h"
17 #include "Win64Exception.h"
18 #include "WinCodeViewLineTables.h"
19 #include "llvm/ADT/SmallString.h"
20 #include "llvm/ADT/Statistic.h"
21 #include "llvm/Analysis/ConstantFolding.h"
22 #include "llvm/Analysis/JumpInstrTableInfo.h"
23 #include "llvm/CodeGen/Analysis.h"
24 #include "llvm/CodeGen/GCMetadataPrinter.h"
25 #include "llvm/CodeGen/MachineConstantPool.h"
26 #include "llvm/CodeGen/MachineFrameInfo.h"
27 #include "llvm/CodeGen/MachineFunction.h"
28 #include "llvm/CodeGen/MachineInstrBundle.h"
29 #include "llvm/CodeGen/MachineJumpTableInfo.h"
30 #include "llvm/CodeGen/MachineLoopInfo.h"
31 #include "llvm/CodeGen/MachineModuleInfo.h"
32 #include "llvm/IR/DataLayout.h"
33 #include "llvm/IR/DebugInfo.h"
34 #include "llvm/IR/Mangler.h"
35 #include "llvm/IR/Module.h"
36 #include "llvm/IR/Operator.h"
37 #include "llvm/MC/MCAsmInfo.h"
38 #include "llvm/MC/MCContext.h"
39 #include "llvm/MC/MCExpr.h"
40 #include "llvm/MC/MCInst.h"
41 #include "llvm/MC/MCSection.h"
42 #include "llvm/MC/MCStreamer.h"
43 #include "llvm/MC/MCSymbol.h"
44 #include "llvm/Support/ErrorHandling.h"
45 #include "llvm/Support/Format.h"
46 #include "llvm/Support/MathExtras.h"
47 #include "llvm/Support/TargetRegistry.h"
48 #include "llvm/Support/Timer.h"
49 #include "llvm/Target/TargetFrameLowering.h"
50 #include "llvm/Target/TargetInstrInfo.h"
51 #include "llvm/Target/TargetLowering.h"
52 #include "llvm/Target/TargetLoweringObjectFile.h"
53 #include "llvm/Target/TargetRegisterInfo.h"
54 #include "llvm/Target/TargetSubtargetInfo.h"
57 #define DEBUG_TYPE "asm-printer"
59 static const char *const DWARFGroupName = "DWARF Emission";
60 static const char *const DbgTimerName = "Debug Info Emission";
61 static const char *const EHTimerName = "DWARF Exception Writer";
62 static const char *const CodeViewLineTablesGroupName = "CodeView Line Tables";
64 STATISTIC(EmittedInsts, "Number of machine instrs printed");
66 char AsmPrinter::ID = 0;
68 typedef DenseMap<GCStrategy*, std::unique_ptr<GCMetadataPrinter>> gcp_map_type;
69 static gcp_map_type &getGCMap(void *&P) {
71 P = new gcp_map_type();
72 return *(gcp_map_type*)P;
76 /// getGVAlignmentLog2 - Return the alignment to use for the specified global
77 /// value in log2 form. This rounds up to the preferred alignment if possible
79 static unsigned getGVAlignmentLog2(const GlobalValue *GV, const DataLayout &TD,
80 unsigned InBits = 0) {
82 if (const GlobalVariable *GVar = dyn_cast<GlobalVariable>(GV))
83 NumBits = TD.getPreferredAlignmentLog(GVar);
85 // If InBits is specified, round it to it.
89 // If the GV has a specified alignment, take it into account.
90 if (GV->getAlignment() == 0)
93 unsigned GVAlign = Log2_32(GV->getAlignment());
95 // If the GVAlign is larger than NumBits, or if we are required to obey
96 // NumBits because the GV has an assigned section, obey it.
97 if (GVAlign > NumBits || GV->hasSection())
102 AsmPrinter::AsmPrinter(TargetMachine &tm, std::unique_ptr<MCStreamer> Streamer)
103 : MachineFunctionPass(ID), TM(tm), MAI(tm.getMCAsmInfo()),
104 OutContext(Streamer->getContext()), OutStreamer(*Streamer.release()),
105 LastMI(nullptr), LastFn(0), Counter(~0U), SetCounter(0) {
110 CurrentFnSym = CurrentFnSymForSize = nullptr;
111 GCMetadataPrinters = nullptr;
112 VerboseAsm = OutStreamer.isVerboseAsm();
115 AsmPrinter::~AsmPrinter() {
116 assert(!DD && Handlers.empty() && "Debug/EH info didn't get finalized");
118 if (GCMetadataPrinters) {
119 gcp_map_type &GCMap = getGCMap(GCMetadataPrinters);
122 GCMetadataPrinters = nullptr;
128 /// getFunctionNumber - Return a unique ID for the current function.
130 unsigned AsmPrinter::getFunctionNumber() const {
131 return MF->getFunctionNumber();
134 const TargetLoweringObjectFile &AsmPrinter::getObjFileLowering() const {
135 return *TM.getObjFileLowering();
138 /// getDataLayout - Return information about data layout.
139 const DataLayout &AsmPrinter::getDataLayout() const {
140 return *TM.getDataLayout();
143 const MCSubtargetInfo &AsmPrinter::getSubtargetInfo() const {
144 return TM.getSubtarget<MCSubtargetInfo>();
147 void AsmPrinter::EmitToStreamer(MCStreamer &S, const MCInst &Inst) {
148 S.EmitInstruction(Inst, getSubtargetInfo());
151 StringRef AsmPrinter::getTargetTriple() const {
152 return TM.getTargetTriple();
155 /// getCurrentSection() - Return the current section we are emitting to.
156 const MCSection *AsmPrinter::getCurrentSection() const {
157 return OutStreamer.getCurrentSection().first;
162 void AsmPrinter::getAnalysisUsage(AnalysisUsage &AU) const {
163 AU.setPreservesAll();
164 MachineFunctionPass::getAnalysisUsage(AU);
165 AU.addRequired<MachineModuleInfo>();
166 AU.addRequired<GCModuleInfo>();
168 AU.addRequired<MachineLoopInfo>();
171 bool AsmPrinter::doInitialization(Module &M) {
172 MMI = getAnalysisIfAvailable<MachineModuleInfo>();
173 MMI->AnalyzeModule(M);
175 // Initialize TargetLoweringObjectFile.
176 const_cast<TargetLoweringObjectFile&>(getObjFileLowering())
177 .Initialize(OutContext, TM);
179 OutStreamer.InitSections(false);
181 Mang = new Mangler(TM.getDataLayout());
183 // Emit the version-min deplyment target directive if needed.
185 // FIXME: If we end up with a collection of these sorts of Darwin-specific
186 // or ELF-specific things, it may make sense to have a platform helper class
187 // that will work with the target helper class. For now keep it here, as the
188 // alternative is duplicated code in each of the target asm printers that
189 // use the directive, where it would need the same conditionalization
191 Triple TT(getTargetTriple());
192 if (TT.isOSDarwin()) {
193 unsigned Major, Minor, Update;
194 TT.getOSVersion(Major, Minor, Update);
195 // If there is a version specified, Major will be non-zero.
197 OutStreamer.EmitVersionMin((TT.isMacOSX() ?
198 MCVM_OSXVersionMin : MCVM_IOSVersionMin),
199 Major, Minor, Update);
202 // Allow the target to emit any magic that it wants at the start of the file.
203 EmitStartOfAsmFile(M);
205 // Very minimal debug info. It is ignored if we emit actual debug info. If we
206 // don't, this at least helps the user find where a global came from.
207 if (MAI->hasSingleParameterDotFile()) {
209 OutStreamer.EmitFileDirective(M.getModuleIdentifier());
212 GCModuleInfo *MI = getAnalysisIfAvailable<GCModuleInfo>();
213 assert(MI && "AsmPrinter didn't require GCModuleInfo?");
215 if (GCMetadataPrinter *MP = GetOrCreateGCPrinter(*I))
216 MP->beginAssembly(M, *MI, *this);
218 // Emit module-level inline asm if it exists.
219 if (!M.getModuleInlineAsm().empty()) {
220 OutStreamer.AddComment("Start of file scope inline assembly");
221 OutStreamer.AddBlankLine();
222 EmitInlineAsm(M.getModuleInlineAsm()+"\n");
223 OutStreamer.AddComment("End of file scope inline assembly");
224 OutStreamer.AddBlankLine();
227 if (MAI->doesSupportDebugInformation()) {
228 bool skip_dwarf = false;
229 if (Triple(TM.getTargetTriple()).isKnownWindowsMSVCEnvironment()) {
230 Handlers.push_back(HandlerInfo(new WinCodeViewLineTables(this),
232 CodeViewLineTablesGroupName));
233 // FIXME: Don't emit DWARF debug info if there's at least one function
234 // with AddressSanitizer instrumentation.
235 // This is a band-aid fix for PR22032.
236 for (auto &F : M.functions()) {
237 if (F.hasFnAttribute(Attribute::SanitizeAddress)) {
244 DD = new DwarfDebug(this, &M);
245 Handlers.push_back(HandlerInfo(DD, DbgTimerName, DWARFGroupName));
249 EHStreamer *ES = nullptr;
250 switch (MAI->getExceptionHandlingType()) {
251 case ExceptionHandling::None:
253 case ExceptionHandling::SjLj:
254 case ExceptionHandling::DwarfCFI:
255 ES = new DwarfCFIException(this);
257 case ExceptionHandling::ARM:
258 ES = new ARMException(this);
260 case ExceptionHandling::WinEH:
261 switch (MAI->getWinEHEncodingType()) {
262 default: llvm_unreachable("unsupported unwinding information encoding");
263 case WinEH::EncodingType::Itanium:
264 ES = new Win64Exception(this);
270 Handlers.push_back(HandlerInfo(ES, EHTimerName, DWARFGroupName));
274 static bool canBeHidden(const GlobalValue *GV, const MCAsmInfo &MAI) {
275 if (!MAI.hasWeakDefCanBeHiddenDirective())
278 return canBeOmittedFromSymbolTable(GV);
281 void AsmPrinter::EmitLinkage(const GlobalValue *GV, MCSymbol *GVSym) const {
282 GlobalValue::LinkageTypes Linkage = GV->getLinkage();
284 case GlobalValue::CommonLinkage:
285 case GlobalValue::LinkOnceAnyLinkage:
286 case GlobalValue::LinkOnceODRLinkage:
287 case GlobalValue::WeakAnyLinkage:
288 case GlobalValue::WeakODRLinkage:
289 if (MAI->hasWeakDefDirective()) {
291 OutStreamer.EmitSymbolAttribute(GVSym, MCSA_Global);
293 if (!canBeHidden(GV, *MAI))
294 // .weak_definition _foo
295 OutStreamer.EmitSymbolAttribute(GVSym, MCSA_WeakDefinition);
297 OutStreamer.EmitSymbolAttribute(GVSym, MCSA_WeakDefAutoPrivate);
298 } else if (MAI->hasLinkOnceDirective()) {
300 OutStreamer.EmitSymbolAttribute(GVSym, MCSA_Global);
301 //NOTE: linkonce is handled by the section the symbol was assigned to.
304 OutStreamer.EmitSymbolAttribute(GVSym, MCSA_Weak);
307 case GlobalValue::AppendingLinkage:
308 // FIXME: appending linkage variables should go into a section of
309 // their name or something. For now, just emit them as external.
310 case GlobalValue::ExternalLinkage:
311 // If external or appending, declare as a global symbol.
313 OutStreamer.EmitSymbolAttribute(GVSym, MCSA_Global);
315 case GlobalValue::PrivateLinkage:
316 case GlobalValue::InternalLinkage:
318 case GlobalValue::AvailableExternallyLinkage:
319 llvm_unreachable("Should never emit this");
320 case GlobalValue::ExternalWeakLinkage:
321 llvm_unreachable("Don't know how to emit these");
323 llvm_unreachable("Unknown linkage type!");
326 void AsmPrinter::getNameWithPrefix(SmallVectorImpl<char> &Name,
327 const GlobalValue *GV) const {
328 TM.getNameWithPrefix(Name, GV, *Mang);
331 MCSymbol *AsmPrinter::getSymbol(const GlobalValue *GV) const {
332 return TM.getSymbol(GV, *Mang);
335 /// EmitGlobalVariable - Emit the specified global variable to the .s file.
336 void AsmPrinter::EmitGlobalVariable(const GlobalVariable *GV) {
337 if (GV->hasInitializer()) {
338 // Check to see if this is a special global used by LLVM, if so, emit it.
339 if (EmitSpecialLLVMGlobal(GV))
343 GV->printAsOperand(OutStreamer.GetCommentOS(),
344 /*PrintType=*/false, GV->getParent());
345 OutStreamer.GetCommentOS() << '\n';
349 MCSymbol *GVSym = getSymbol(GV);
350 EmitVisibility(GVSym, GV->getVisibility(), !GV->isDeclaration());
352 if (!GV->hasInitializer()) // External globals require no extra code.
355 GVSym->redefineIfPossible();
356 if (GVSym->isDefined() || GVSym->isVariable())
357 report_fatal_error("symbol '" + Twine(GVSym->getName()) +
358 "' is already defined");
360 if (MAI->hasDotTypeDotSizeDirective())
361 OutStreamer.EmitSymbolAttribute(GVSym, MCSA_ELF_TypeObject);
363 SectionKind GVKind = TargetLoweringObjectFile::getKindForGlobal(GV, TM);
365 const DataLayout *DL = TM.getDataLayout();
366 uint64_t Size = DL->getTypeAllocSize(GV->getType()->getElementType());
368 // If the alignment is specified, we *must* obey it. Overaligning a global
369 // with a specified alignment is a prompt way to break globals emitted to
370 // sections and expected to be contiguous (e.g. ObjC metadata).
371 unsigned AlignLog = getGVAlignmentLog2(GV, *DL);
373 for (const HandlerInfo &HI : Handlers) {
374 NamedRegionTimer T(HI.TimerName, HI.TimerGroupName, TimePassesIsEnabled);
375 HI.Handler->setSymbolSize(GVSym, Size);
378 // Handle common and BSS local symbols (.lcomm).
379 if (GVKind.isCommon() || GVKind.isBSSLocal()) {
380 if (Size == 0) Size = 1; // .comm Foo, 0 is undefined, avoid it.
381 unsigned Align = 1 << AlignLog;
383 // Handle common symbols.
384 if (GVKind.isCommon()) {
385 if (!getObjFileLowering().getCommDirectiveSupportsAlignment())
389 OutStreamer.EmitCommonSymbol(GVSym, Size, Align);
393 // Handle local BSS symbols.
394 if (MAI->hasMachoZeroFillDirective()) {
395 const MCSection *TheSection =
396 getObjFileLowering().SectionForGlobal(GV, GVKind, *Mang, TM);
397 // .zerofill __DATA, __bss, _foo, 400, 5
398 OutStreamer.EmitZerofill(TheSection, GVSym, Size, Align);
402 // Use .lcomm only if it supports user-specified alignment.
403 // Otherwise, while it would still be correct to use .lcomm in some
404 // cases (e.g. when Align == 1), the external assembler might enfore
405 // some -unknown- default alignment behavior, which could cause
406 // spurious differences between external and integrated assembler.
407 // Prefer to simply fall back to .local / .comm in this case.
408 if (MAI->getLCOMMDirectiveAlignmentType() != LCOMM::NoAlignment) {
410 OutStreamer.EmitLocalCommonSymbol(GVSym, Size, Align);
414 if (!getObjFileLowering().getCommDirectiveSupportsAlignment())
418 OutStreamer.EmitSymbolAttribute(GVSym, MCSA_Local);
420 OutStreamer.EmitCommonSymbol(GVSym, Size, Align);
424 const MCSection *TheSection =
425 getObjFileLowering().SectionForGlobal(GV, GVKind, *Mang, TM);
427 // Handle the zerofill directive on darwin, which is a special form of BSS
429 if (GVKind.isBSSExtern() && MAI->hasMachoZeroFillDirective()) {
430 if (Size == 0) Size = 1; // zerofill of 0 bytes is undefined.
433 OutStreamer.EmitSymbolAttribute(GVSym, MCSA_Global);
434 // .zerofill __DATA, __common, _foo, 400, 5
435 OutStreamer.EmitZerofill(TheSection, GVSym, Size, 1 << AlignLog);
439 // Handle thread local data for mach-o which requires us to output an
440 // additional structure of data and mangle the original symbol so that we
441 // can reference it later.
443 // TODO: This should become an "emit thread local global" method on TLOF.
444 // All of this macho specific stuff should be sunk down into TLOFMachO and
445 // stuff like "TLSExtraDataSection" should no longer be part of the parent
446 // TLOF class. This will also make it more obvious that stuff like
447 // MCStreamer::EmitTBSSSymbol is macho specific and only called from macho
449 if (GVKind.isThreadLocal() && MAI->hasMachoTBSSDirective()) {
450 // Emit the .tbss symbol
452 OutContext.GetOrCreateSymbol(GVSym->getName() + Twine("$tlv$init"));
454 if (GVKind.isThreadBSS()) {
455 TheSection = getObjFileLowering().getTLSBSSSection();
456 OutStreamer.EmitTBSSSymbol(TheSection, MangSym, Size, 1 << AlignLog);
457 } else if (GVKind.isThreadData()) {
458 OutStreamer.SwitchSection(TheSection);
460 EmitAlignment(AlignLog, GV);
461 OutStreamer.EmitLabel(MangSym);
463 EmitGlobalConstant(GV->getInitializer());
466 OutStreamer.AddBlankLine();
468 // Emit the variable struct for the runtime.
469 const MCSection *TLVSect
470 = getObjFileLowering().getTLSExtraDataSection();
472 OutStreamer.SwitchSection(TLVSect);
473 // Emit the linkage here.
474 EmitLinkage(GV, GVSym);
475 OutStreamer.EmitLabel(GVSym);
477 // Three pointers in size:
478 // - __tlv_bootstrap - used to make sure support exists
479 // - spare pointer, used when mapped by the runtime
480 // - pointer to mangled symbol above with initializer
481 unsigned PtrSize = DL->getPointerTypeSize(GV->getType());
482 OutStreamer.EmitSymbolValue(GetExternalSymbolSymbol("_tlv_bootstrap"),
484 OutStreamer.EmitIntValue(0, PtrSize);
485 OutStreamer.EmitSymbolValue(MangSym, PtrSize);
487 OutStreamer.AddBlankLine();
491 OutStreamer.SwitchSection(TheSection);
493 EmitLinkage(GV, GVSym);
494 EmitAlignment(AlignLog, GV);
496 OutStreamer.EmitLabel(GVSym);
498 EmitGlobalConstant(GV->getInitializer());
500 if (MAI->hasDotTypeDotSizeDirective())
502 OutStreamer.EmitELFSize(GVSym, MCConstantExpr::Create(Size, OutContext));
504 OutStreamer.AddBlankLine();
507 /// EmitFunctionHeader - This method emits the header for the current
509 void AsmPrinter::EmitFunctionHeader() {
510 // Print out constants referenced by the function
513 // Print the 'header' of function.
514 const Function *F = MF->getFunction();
516 OutStreamer.SwitchSection(
517 getObjFileLowering().SectionForGlobal(F, *Mang, TM));
518 EmitVisibility(CurrentFnSym, F->getVisibility());
520 EmitLinkage(F, CurrentFnSym);
521 EmitAlignment(MF->getAlignment(), F);
523 if (MAI->hasDotTypeDotSizeDirective())
524 OutStreamer.EmitSymbolAttribute(CurrentFnSym, MCSA_ELF_TypeFunction);
527 F->printAsOperand(OutStreamer.GetCommentOS(),
528 /*PrintType=*/false, F->getParent());
529 OutStreamer.GetCommentOS() << '\n';
532 // Emit the prefix data.
533 if (F->hasPrefixData())
534 EmitGlobalConstant(F->getPrefixData());
536 // Emit the CurrentFnSym. This is a virtual function to allow targets to
537 // do their wild and crazy things as required.
538 EmitFunctionEntryLabel();
540 // If the function had address-taken blocks that got deleted, then we have
541 // references to the dangling symbols. Emit them at the start of the function
542 // so that we don't get references to undefined symbols.
543 std::vector<MCSymbol*> DeadBlockSyms;
544 MMI->takeDeletedSymbolsForFunction(F, DeadBlockSyms);
545 for (unsigned i = 0, e = DeadBlockSyms.size(); i != e; ++i) {
546 OutStreamer.AddComment("Address taken block that was later removed");
547 OutStreamer.EmitLabel(DeadBlockSyms[i]);
550 // Emit pre-function debug and/or EH information.
551 for (const HandlerInfo &HI : Handlers) {
552 NamedRegionTimer T(HI.TimerName, HI.TimerGroupName, TimePassesIsEnabled);
553 HI.Handler->beginFunction(MF);
556 // Emit the prologue data.
557 if (F->hasPrologueData())
558 EmitGlobalConstant(F->getPrologueData());
561 /// EmitFunctionEntryLabel - Emit the label that is the entrypoint for the
562 /// function. This can be overridden by targets as required to do custom stuff.
563 void AsmPrinter::EmitFunctionEntryLabel() {
564 CurrentFnSym->redefineIfPossible();
566 // The function label could have already been emitted if two symbols end up
567 // conflicting due to asm renaming. Detect this and emit an error.
568 if (CurrentFnSym->isVariable())
569 report_fatal_error("'" + Twine(CurrentFnSym->getName()) +
570 "' is a protected alias");
571 if (CurrentFnSym->isDefined())
572 report_fatal_error("'" + Twine(CurrentFnSym->getName()) +
573 "' label emitted multiple times to assembly file");
575 return OutStreamer.EmitLabel(CurrentFnSym);
578 /// emitComments - Pretty-print comments for instructions.
579 static void emitComments(const MachineInstr &MI, raw_ostream &CommentOS) {
580 const MachineFunction *MF = MI.getParent()->getParent();
581 const TargetInstrInfo *TII = MF->getSubtarget().getInstrInfo();
583 // Check for spills and reloads
586 const MachineFrameInfo *FrameInfo = MF->getFrameInfo();
588 // We assume a single instruction only has a spill or reload, not
590 const MachineMemOperand *MMO;
591 if (TII->isLoadFromStackSlotPostFE(&MI, FI)) {
592 if (FrameInfo->isSpillSlotObjectIndex(FI)) {
593 MMO = *MI.memoperands_begin();
594 CommentOS << MMO->getSize() << "-byte Reload\n";
596 } else if (TII->hasLoadFromStackSlot(&MI, MMO, FI)) {
597 if (FrameInfo->isSpillSlotObjectIndex(FI))
598 CommentOS << MMO->getSize() << "-byte Folded Reload\n";
599 } else if (TII->isStoreToStackSlotPostFE(&MI, FI)) {
600 if (FrameInfo->isSpillSlotObjectIndex(FI)) {
601 MMO = *MI.memoperands_begin();
602 CommentOS << MMO->getSize() << "-byte Spill\n";
604 } else if (TII->hasStoreToStackSlot(&MI, MMO, FI)) {
605 if (FrameInfo->isSpillSlotObjectIndex(FI))
606 CommentOS << MMO->getSize() << "-byte Folded Spill\n";
609 // Check for spill-induced copies
610 if (MI.getAsmPrinterFlag(MachineInstr::ReloadReuse))
611 CommentOS << " Reload Reuse\n";
614 /// emitImplicitDef - This method emits the specified machine instruction
615 /// that is an implicit def.
616 void AsmPrinter::emitImplicitDef(const MachineInstr *MI) const {
617 unsigned RegNo = MI->getOperand(0).getReg();
618 OutStreamer.AddComment(
619 Twine("implicit-def: ") +
620 TM.getSubtargetImpl()->getRegisterInfo()->getName(RegNo));
621 OutStreamer.AddBlankLine();
624 static void emitKill(const MachineInstr *MI, AsmPrinter &AP) {
625 std::string Str = "kill:";
626 for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
627 const MachineOperand &Op = MI->getOperand(i);
628 assert(Op.isReg() && "KILL instruction must have only register operands");
630 Str += AP.TM.getSubtargetImpl()->getRegisterInfo()->getName(Op.getReg());
631 Str += (Op.isDef() ? "<def>" : "<kill>");
633 AP.OutStreamer.AddComment(Str);
634 AP.OutStreamer.AddBlankLine();
637 /// emitDebugValueComment - This method handles the target-independent form
638 /// of DBG_VALUE, returning true if it was able to do so. A false return
639 /// means the target will need to handle MI in EmitInstruction.
640 static bool emitDebugValueComment(const MachineInstr *MI, AsmPrinter &AP) {
641 // This code handles only the 4-operand target-independent form.
642 if (MI->getNumOperands() != 4)
645 SmallString<128> Str;
646 raw_svector_ostream OS(Str);
647 OS << "DEBUG_VALUE: ";
649 DIVariable V = MI->getDebugVariable();
650 if (V.getContext().isSubprogram()) {
651 StringRef Name = DISubprogram(V.getContext()).getDisplayName();
657 DIExpression Expr = MI->getDebugExpression();
658 if (Expr.isBitPiece())
659 OS << " [bit_piece offset=" << Expr.getBitPieceOffset()
660 << " size=" << Expr.getBitPieceSize() << "]";
663 // The second operand is only an offset if it's an immediate.
664 bool Deref = MI->getOperand(0).isReg() && MI->getOperand(1).isImm();
665 int64_t Offset = Deref ? MI->getOperand(1).getImm() : 0;
667 // Register or immediate value. Register 0 means undef.
668 if (MI->getOperand(0).isFPImm()) {
669 APFloat APF = APFloat(MI->getOperand(0).getFPImm()->getValueAPF());
670 if (MI->getOperand(0).getFPImm()->getType()->isFloatTy()) {
671 OS << (double)APF.convertToFloat();
672 } else if (MI->getOperand(0).getFPImm()->getType()->isDoubleTy()) {
673 OS << APF.convertToDouble();
675 // There is no good way to print long double. Convert a copy to
676 // double. Ah well, it's only a comment.
678 APF.convert(APFloat::IEEEdouble, APFloat::rmNearestTiesToEven,
680 OS << "(long double) " << APF.convertToDouble();
682 } else if (MI->getOperand(0).isImm()) {
683 OS << MI->getOperand(0).getImm();
684 } else if (MI->getOperand(0).isCImm()) {
685 MI->getOperand(0).getCImm()->getValue().print(OS, false /*isSigned*/);
688 if (MI->getOperand(0).isReg()) {
689 Reg = MI->getOperand(0).getReg();
691 assert(MI->getOperand(0).isFI() && "Unknown operand type");
692 const TargetFrameLowering *TFI =
693 AP.TM.getSubtargetImpl()->getFrameLowering();
694 Offset += TFI->getFrameIndexReference(*AP.MF,
695 MI->getOperand(0).getIndex(), Reg);
699 // Suppress offset, it is not meaningful here.
701 // NOTE: Want this comment at start of line, don't emit with AddComment.
702 AP.OutStreamer.emitRawComment(OS.str());
707 OS << AP.TM.getSubtargetImpl()->getRegisterInfo()->getName(Reg);
711 OS << '+' << Offset << ']';
713 // NOTE: Want this comment at start of line, don't emit with AddComment.
714 AP.OutStreamer.emitRawComment(OS.str());
718 AsmPrinter::CFIMoveType AsmPrinter::needsCFIMoves() {
719 if (MAI->getExceptionHandlingType() == ExceptionHandling::DwarfCFI &&
720 MF->getFunction()->needsUnwindTableEntry())
723 if (MMI->hasDebugInfo())
729 bool AsmPrinter::needsSEHMoves() {
730 return MAI->usesWindowsCFI() && MF->getFunction()->needsUnwindTableEntry();
733 void AsmPrinter::emitCFIInstruction(const MachineInstr &MI) {
734 ExceptionHandling ExceptionHandlingType = MAI->getExceptionHandlingType();
735 if (ExceptionHandlingType != ExceptionHandling::DwarfCFI &&
736 ExceptionHandlingType != ExceptionHandling::ARM)
739 if (needsCFIMoves() == CFI_M_None)
742 const MachineModuleInfo &MMI = MF->getMMI();
743 const std::vector<MCCFIInstruction> &Instrs = MMI.getFrameInstructions();
744 unsigned CFIIndex = MI.getOperand(0).getCFIIndex();
745 const MCCFIInstruction &CFI = Instrs[CFIIndex];
746 emitCFIInstruction(CFI);
749 void AsmPrinter::emitFrameAlloc(const MachineInstr &MI) {
750 // The operands are the MCSymbol and the frame offset of the allocation.
751 MCSymbol *FrameAllocSym = MI.getOperand(0).getMCSymbol();
752 int FrameOffset = MI.getOperand(1).getImm();
754 // Emit a symbol assignment.
755 OutStreamer.EmitAssignment(FrameAllocSym,
756 MCConstantExpr::Create(FrameOffset, OutContext));
759 /// EmitFunctionBody - This method emits the body and trailer for a
761 void AsmPrinter::EmitFunctionBody() {
762 // Emit target-specific gunk before the function body.
763 EmitFunctionBodyStart();
765 bool ShouldPrintDebugScopes = MMI->hasDebugInfo();
767 // Print out code for the function.
768 bool HasAnyRealCode = false;
769 for (auto &MBB : *MF) {
770 // Print a label for the basic block.
771 EmitBasicBlockStart(MBB);
772 for (auto &MI : MBB) {
774 // Print the assembly for the instruction.
775 if (!MI.isPosition() && !MI.isImplicitDef() && !MI.isKill() &&
776 !MI.isDebugValue()) {
777 HasAnyRealCode = true;
781 if (ShouldPrintDebugScopes) {
782 for (const HandlerInfo &HI : Handlers) {
783 NamedRegionTimer T(HI.TimerName, HI.TimerGroupName,
784 TimePassesIsEnabled);
785 HI.Handler->beginInstruction(&MI);
790 emitComments(MI, OutStreamer.GetCommentOS());
792 switch (MI.getOpcode()) {
793 case TargetOpcode::CFI_INSTRUCTION:
794 emitCFIInstruction(MI);
797 case TargetOpcode::FRAME_ALLOC:
801 case TargetOpcode::EH_LABEL:
802 case TargetOpcode::GC_LABEL:
803 OutStreamer.EmitLabel(MI.getOperand(0).getMCSymbol());
805 case TargetOpcode::INLINEASM:
808 case TargetOpcode::DBG_VALUE:
810 if (!emitDebugValueComment(&MI, *this))
811 EmitInstruction(&MI);
814 case TargetOpcode::IMPLICIT_DEF:
815 if (isVerbose()) emitImplicitDef(&MI);
817 case TargetOpcode::KILL:
818 if (isVerbose()) emitKill(&MI, *this);
821 EmitInstruction(&MI);
825 if (ShouldPrintDebugScopes) {
826 for (const HandlerInfo &HI : Handlers) {
827 NamedRegionTimer T(HI.TimerName, HI.TimerGroupName,
828 TimePassesIsEnabled);
829 HI.Handler->endInstruction();
834 EmitBasicBlockEnd(MBB);
837 // If the function is empty and the object file uses .subsections_via_symbols,
838 // then we need to emit *something* to the function body to prevent the
839 // labels from collapsing together. Just emit a noop.
840 if ((MAI->hasSubsectionsViaSymbols() && !HasAnyRealCode)) {
842 MF->getSubtarget().getInstrInfo()->getNoopForMachoTarget(Noop);
843 OutStreamer.AddComment("avoids zero-length function");
845 // Targets can opt-out of emitting the noop here by leaving the opcode
847 if (Noop.getOpcode())
848 OutStreamer.EmitInstruction(Noop, getSubtargetInfo());
851 const Function *F = MF->getFunction();
852 for (const auto &BB : *F) {
853 if (!BB.hasAddressTaken())
855 MCSymbol *Sym = GetBlockAddressSymbol(&BB);
856 if (Sym->isDefined())
858 OutStreamer.AddComment("Address of block that was removed by CodeGen");
859 OutStreamer.EmitLabel(Sym);
862 // Emit target-specific gunk after the function body.
863 EmitFunctionBodyEnd();
865 // If the target wants a .size directive for the size of the function, emit
867 if (MAI->hasDotTypeDotSizeDirective()) {
868 // Create a symbol for the end of function, so we can get the size as
869 // difference between the function label and the temp label.
870 MCSymbol *FnEndLabel = OutContext.CreateTempSymbol();
871 OutStreamer.EmitLabel(FnEndLabel);
873 const MCExpr *SizeExp =
874 MCBinaryExpr::CreateSub(MCSymbolRefExpr::Create(FnEndLabel, OutContext),
875 MCSymbolRefExpr::Create(CurrentFnSymForSize,
878 OutStreamer.EmitELFSize(CurrentFnSym, SizeExp);
881 // Emit post-function debug and/or EH information.
882 for (const HandlerInfo &HI : Handlers) {
883 NamedRegionTimer T(HI.TimerName, HI.TimerGroupName, TimePassesIsEnabled);
884 HI.Handler->endFunction(MF);
888 // Print out jump tables referenced by the function.
891 OutStreamer.AddBlankLine();
894 bool AsmPrinter::doFinalization(Module &M) {
895 // Emit global variables.
896 for (const auto &G : M.globals())
897 EmitGlobalVariable(&G);
899 // Emit visibility info for declarations
900 for (const Function &F : M) {
901 if (!F.isDeclaration())
903 GlobalValue::VisibilityTypes V = F.getVisibility();
904 if (V == GlobalValue::DefaultVisibility)
907 MCSymbol *Name = getSymbol(&F);
908 EmitVisibility(Name, V, false);
911 // Get information about jump-instruction tables to print.
912 JumpInstrTableInfo *JITI = getAnalysisIfAvailable<JumpInstrTableInfo>();
914 if (JITI && !JITI->getTables().empty()) {
915 // Since we're at the module level we can't use a function specific
916 // MCSubtargetInfo - instead create one with the module defaults.
917 std::unique_ptr<MCSubtargetInfo> STI(TM.getTarget().createMCSubtargetInfo(
918 TM.getTargetTriple(), TM.getTargetCPU(), TM.getTargetFeatureString()));
919 unsigned Arch = Triple(getTargetTriple()).getArch();
920 bool IsThumb = (Arch == Triple::thumb || Arch == Triple::thumbeb);
921 const TargetInstrInfo *TII = TM.getSubtargetImpl()->getInstrInfo();
923 TII->getTrap(TrapInst);
924 unsigned LogAlignment = llvm::Log2_64(JITI->entryByteAlignment());
926 // Emit the right section for these functions.
927 OutStreamer.SwitchSection(OutContext.getObjectFileInfo()->getTextSection());
928 for (const auto &KV : JITI->getTables()) {
930 for (const auto &FunPair : KV.second) {
931 // Emit the function labels to make this be a function entry point.
933 OutContext.GetOrCreateSymbol(FunPair.second->getName());
934 EmitAlignment(LogAlignment);
936 OutStreamer.EmitThumbFunc(FunSym);
937 if (MAI->hasDotTypeDotSizeDirective())
938 OutStreamer.EmitSymbolAttribute(FunSym, MCSA_ELF_TypeFunction);
939 OutStreamer.EmitLabel(FunSym);
941 // Emit the jump instruction to transfer control to the original
944 MCSymbol *TargetSymbol =
945 OutContext.GetOrCreateSymbol(FunPair.first->getName());
946 const MCSymbolRefExpr *TargetSymRef =
947 MCSymbolRefExpr::Create(TargetSymbol, MCSymbolRefExpr::VK_PLT,
949 TII->getUnconditionalBranch(JumpToFun, TargetSymRef);
950 OutStreamer.EmitInstruction(JumpToFun, *STI);
954 // Emit enough padding instructions to fill up to the next power of two.
955 uint64_t Remaining = NextPowerOf2(Count) - Count;
956 for (uint64_t C = 0; C < Remaining; ++C) {
957 EmitAlignment(LogAlignment);
958 OutStreamer.EmitInstruction(TrapInst, *STI);
964 // Emit module flags.
965 SmallVector<Module::ModuleFlagEntry, 8> ModuleFlags;
966 M.getModuleFlagsMetadata(ModuleFlags);
967 if (!ModuleFlags.empty())
968 getObjFileLowering().emitModuleFlags(OutStreamer, ModuleFlags, *Mang, TM);
970 // Make sure we wrote out everything we need.
973 // Finalize debug and EH information.
974 for (const HandlerInfo &HI : Handlers) {
975 NamedRegionTimer T(HI.TimerName, HI.TimerGroupName,
976 TimePassesIsEnabled);
977 HI.Handler->endModule();
983 // If the target wants to know about weak references, print them all.
984 if (MAI->getWeakRefDirective()) {
985 // FIXME: This is not lazy, it would be nice to only print weak references
986 // to stuff that is actually used. Note that doing so would require targets
987 // to notice uses in operands (due to constant exprs etc). This should
988 // happen with the MC stuff eventually.
990 // Print out module-level global variables here.
991 for (const auto &G : M.globals()) {
992 if (!G.hasExternalWeakLinkage())
994 OutStreamer.EmitSymbolAttribute(getSymbol(&G), MCSA_WeakReference);
997 for (const auto &F : M) {
998 if (!F.hasExternalWeakLinkage())
1000 OutStreamer.EmitSymbolAttribute(getSymbol(&F), MCSA_WeakReference);
1004 OutStreamer.AddBlankLine();
1005 for (const auto &Alias : M.aliases()) {
1006 MCSymbol *Name = getSymbol(&Alias);
1008 if (Alias.hasExternalLinkage() || !MAI->getWeakRefDirective())
1009 OutStreamer.EmitSymbolAttribute(Name, MCSA_Global);
1010 else if (Alias.hasWeakLinkage() || Alias.hasLinkOnceLinkage())
1011 OutStreamer.EmitSymbolAttribute(Name, MCSA_WeakReference);
1013 assert(Alias.hasLocalLinkage() && "Invalid alias linkage");
1015 EmitVisibility(Name, Alias.getVisibility());
1017 // Emit the directives as assignments aka .set:
1018 OutStreamer.EmitAssignment(Name, lowerConstant(Alias.getAliasee()));
1021 GCModuleInfo *MI = getAnalysisIfAvailable<GCModuleInfo>();
1022 assert(MI && "AsmPrinter didn't require GCModuleInfo?");
1023 for (GCModuleInfo::iterator I = MI->end(), E = MI->begin(); I != E; )
1024 if (GCMetadataPrinter *MP = GetOrCreateGCPrinter(**--I))
1025 MP->finishAssembly(M, *MI, *this);
1027 // Emit llvm.ident metadata in an '.ident' directive.
1028 EmitModuleIdents(M);
1030 // Emit __morestack address if needed for indirect calls.
1031 if (MMI->usesMorestackAddr()) {
1032 const MCSection *ReadOnlySection =
1033 getObjFileLowering().getSectionForConstant(SectionKind::getReadOnly(),
1035 OutStreamer.SwitchSection(ReadOnlySection);
1037 MCSymbol *AddrSymbol =
1038 OutContext.GetOrCreateSymbol(StringRef("__morestack_addr"));
1039 OutStreamer.EmitLabel(AddrSymbol);
1041 unsigned PtrSize = TM.getDataLayout()->getPointerSize(0);
1042 OutStreamer.EmitSymbolValue(GetExternalSymbolSymbol("__morestack"),
1046 // If we don't have any trampolines, then we don't require stack memory
1047 // to be executable. Some targets have a directive to declare this.
1048 Function *InitTrampolineIntrinsic = M.getFunction("llvm.init.trampoline");
1049 if (!InitTrampolineIntrinsic || InitTrampolineIntrinsic->use_empty())
1050 if (const MCSection *S = MAI->getNonexecutableStackSection(OutContext))
1051 OutStreamer.SwitchSection(S);
1053 // Allow the target to emit any magic that it wants at the end of the file,
1054 // after everything else has gone out.
1055 EmitEndOfAsmFile(M);
1057 delete Mang; Mang = nullptr;
1060 OutStreamer.Finish();
1061 OutStreamer.reset();
1066 void AsmPrinter::SetupMachineFunction(MachineFunction &MF) {
1068 // Get the function symbol.
1069 CurrentFnSym = getSymbol(MF.getFunction());
1070 CurrentFnSymForSize = CurrentFnSym;
1073 LI = &getAnalysis<MachineLoopInfo>();
1077 // SectionCPs - Keep track the alignment, constpool entries per Section.
1081 SmallVector<unsigned, 4> CPEs;
1082 SectionCPs(const MCSection *s, unsigned a) : S(s), Alignment(a) {}
1086 /// EmitConstantPool - Print to the current output stream assembly
1087 /// representations of the constants in the constant pool MCP. This is
1088 /// used to print out constants which have been "spilled to memory" by
1089 /// the code generator.
1091 void AsmPrinter::EmitConstantPool() {
1092 const MachineConstantPool *MCP = MF->getConstantPool();
1093 const std::vector<MachineConstantPoolEntry> &CP = MCP->getConstants();
1094 if (CP.empty()) return;
1096 // Calculate sections for constant pool entries. We collect entries to go into
1097 // the same section together to reduce amount of section switch statements.
1098 SmallVector<SectionCPs, 4> CPSections;
1099 for (unsigned i = 0, e = CP.size(); i != e; ++i) {
1100 const MachineConstantPoolEntry &CPE = CP[i];
1101 unsigned Align = CPE.getAlignment();
1104 CPE.getSectionKind(TM.getDataLayout());
1106 const Constant *C = nullptr;
1107 if (!CPE.isMachineConstantPoolEntry())
1108 C = CPE.Val.ConstVal;
1110 const MCSection *S = getObjFileLowering().getSectionForConstant(Kind, C);
1112 // The number of sections are small, just do a linear search from the
1113 // last section to the first.
1115 unsigned SecIdx = CPSections.size();
1116 while (SecIdx != 0) {
1117 if (CPSections[--SecIdx].S == S) {
1123 SecIdx = CPSections.size();
1124 CPSections.push_back(SectionCPs(S, Align));
1127 if (Align > CPSections[SecIdx].Alignment)
1128 CPSections[SecIdx].Alignment = Align;
1129 CPSections[SecIdx].CPEs.push_back(i);
1132 // Now print stuff into the calculated sections.
1133 const MCSection *CurSection = nullptr;
1134 unsigned Offset = 0;
1135 for (unsigned i = 0, e = CPSections.size(); i != e; ++i) {
1136 for (unsigned j = 0, ee = CPSections[i].CPEs.size(); j != ee; ++j) {
1137 unsigned CPI = CPSections[i].CPEs[j];
1138 MCSymbol *Sym = GetCPISymbol(CPI);
1139 if (!Sym->isUndefined())
1142 if (CurSection != CPSections[i].S) {
1143 OutStreamer.SwitchSection(CPSections[i].S);
1144 EmitAlignment(Log2_32(CPSections[i].Alignment));
1145 CurSection = CPSections[i].S;
1149 MachineConstantPoolEntry CPE = CP[CPI];
1151 // Emit inter-object padding for alignment.
1152 unsigned AlignMask = CPE.getAlignment() - 1;
1153 unsigned NewOffset = (Offset + AlignMask) & ~AlignMask;
1154 OutStreamer.EmitZeros(NewOffset - Offset);
1156 Type *Ty = CPE.getType();
1157 Offset = NewOffset +
1158 TM.getDataLayout()->getTypeAllocSize(Ty);
1160 OutStreamer.EmitLabel(Sym);
1161 if (CPE.isMachineConstantPoolEntry())
1162 EmitMachineConstantPoolValue(CPE.Val.MachineCPVal);
1164 EmitGlobalConstant(CPE.Val.ConstVal);
1169 /// EmitJumpTableInfo - Print assembly representations of the jump tables used
1170 /// by the current function to the current output stream.
1172 void AsmPrinter::EmitJumpTableInfo() {
1173 const DataLayout *DL = MF->getTarget().getDataLayout();
1174 const MachineJumpTableInfo *MJTI = MF->getJumpTableInfo();
1176 if (MJTI->getEntryKind() == MachineJumpTableInfo::EK_Inline) return;
1177 const std::vector<MachineJumpTableEntry> &JT = MJTI->getJumpTables();
1178 if (JT.empty()) return;
1180 // Pick the directive to use to print the jump table entries, and switch to
1181 // the appropriate section.
1182 const Function *F = MF->getFunction();
1183 const TargetLoweringObjectFile &TLOF = getObjFileLowering();
1184 bool JTInDiffSection = !TLOF.shouldPutJumpTableInFunctionSection(
1185 MJTI->getEntryKind() == MachineJumpTableInfo::EK_LabelDifference32,
1187 if (!JTInDiffSection) {
1188 OutStreamer.SwitchSection(TLOF.SectionForGlobal(F, *Mang, TM));
1190 // Otherwise, drop it in the readonly section.
1191 const MCSection *ReadOnlySection =
1192 TLOF.getSectionForJumpTable(*F, *Mang, TM);
1193 OutStreamer.SwitchSection(ReadOnlySection);
1196 EmitAlignment(Log2_32(
1197 MJTI->getEntryAlignment(*TM.getDataLayout())));
1199 // Jump tables in code sections are marked with a data_region directive
1200 // where that's supported.
1201 if (!JTInDiffSection)
1202 OutStreamer.EmitDataRegion(MCDR_DataRegionJT32);
1204 for (unsigned JTI = 0, e = JT.size(); JTI != e; ++JTI) {
1205 const std::vector<MachineBasicBlock*> &JTBBs = JT[JTI].MBBs;
1207 // If this jump table was deleted, ignore it.
1208 if (JTBBs.empty()) continue;
1210 // For the EK_LabelDifference32 entry, if using .set avoids a relocation,
1211 /// emit a .set directive for each unique entry.
1212 if (MJTI->getEntryKind() == MachineJumpTableInfo::EK_LabelDifference32 &&
1213 MAI->doesSetDirectiveSuppressesReloc()) {
1214 SmallPtrSet<const MachineBasicBlock*, 16> EmittedSets;
1215 const TargetLowering *TLI = MF->getSubtarget().getTargetLowering();
1216 const MCExpr *Base = TLI->getPICJumpTableRelocBaseExpr(MF,JTI,OutContext);
1217 for (unsigned ii = 0, ee = JTBBs.size(); ii != ee; ++ii) {
1218 const MachineBasicBlock *MBB = JTBBs[ii];
1219 if (!EmittedSets.insert(MBB).second)
1222 // .set LJTSet, LBB32-base
1224 MCSymbolRefExpr::Create(MBB->getSymbol(), OutContext);
1225 OutStreamer.EmitAssignment(GetJTSetSymbol(JTI, MBB->getNumber()),
1226 MCBinaryExpr::CreateSub(LHS, Base, OutContext));
1230 // On some targets (e.g. Darwin) we want to emit two consecutive labels
1231 // before each jump table. The first label is never referenced, but tells
1232 // the assembler and linker the extents of the jump table object. The
1233 // second label is actually referenced by the code.
1234 if (JTInDiffSection && DL->hasLinkerPrivateGlobalPrefix())
1235 // FIXME: This doesn't have to have any specific name, just any randomly
1236 // named and numbered 'l' label would work. Simplify GetJTISymbol.
1237 OutStreamer.EmitLabel(GetJTISymbol(JTI, true));
1239 OutStreamer.EmitLabel(GetJTISymbol(JTI));
1241 for (unsigned ii = 0, ee = JTBBs.size(); ii != ee; ++ii)
1242 EmitJumpTableEntry(MJTI, JTBBs[ii], JTI);
1244 if (!JTInDiffSection)
1245 OutStreamer.EmitDataRegion(MCDR_DataRegionEnd);
1248 /// EmitJumpTableEntry - Emit a jump table entry for the specified MBB to the
1250 void AsmPrinter::EmitJumpTableEntry(const MachineJumpTableInfo *MJTI,
1251 const MachineBasicBlock *MBB,
1252 unsigned UID) const {
1253 assert(MBB && MBB->getNumber() >= 0 && "Invalid basic block");
1254 const MCExpr *Value = nullptr;
1255 switch (MJTI->getEntryKind()) {
1256 case MachineJumpTableInfo::EK_Inline:
1257 llvm_unreachable("Cannot emit EK_Inline jump table entry");
1258 case MachineJumpTableInfo::EK_Custom32:
1259 Value = MF->getSubtarget().getTargetLowering()->LowerCustomJumpTableEntry(
1260 MJTI, MBB, UID, OutContext);
1262 case MachineJumpTableInfo::EK_BlockAddress:
1263 // EK_BlockAddress - Each entry is a plain address of block, e.g.:
1265 Value = MCSymbolRefExpr::Create(MBB->getSymbol(), OutContext);
1267 case MachineJumpTableInfo::EK_GPRel32BlockAddress: {
1268 // EK_GPRel32BlockAddress - Each entry is an address of block, encoded
1269 // with a relocation as gp-relative, e.g.:
1271 MCSymbol *MBBSym = MBB->getSymbol();
1272 OutStreamer.EmitGPRel32Value(MCSymbolRefExpr::Create(MBBSym, OutContext));
1276 case MachineJumpTableInfo::EK_GPRel64BlockAddress: {
1277 // EK_GPRel64BlockAddress - Each entry is an address of block, encoded
1278 // with a relocation as gp-relative, e.g.:
1280 MCSymbol *MBBSym = MBB->getSymbol();
1281 OutStreamer.EmitGPRel64Value(MCSymbolRefExpr::Create(MBBSym, OutContext));
1285 case MachineJumpTableInfo::EK_LabelDifference32: {
1286 // Each entry is the address of the block minus the address of the jump
1287 // table. This is used for PIC jump tables where gprel32 is not supported.
1289 // .word LBB123 - LJTI1_2
1290 // If the .set directive avoids relocations, this is emitted as:
1291 // .set L4_5_set_123, LBB123 - LJTI1_2
1292 // .word L4_5_set_123
1293 if (MAI->doesSetDirectiveSuppressesReloc()) {
1294 Value = MCSymbolRefExpr::Create(GetJTSetSymbol(UID, MBB->getNumber()),
1298 Value = MCSymbolRefExpr::Create(MBB->getSymbol(), OutContext);
1299 const TargetLowering *TLI = TM.getSubtargetImpl()->getTargetLowering();
1300 const MCExpr *Base = TLI->getPICJumpTableRelocBaseExpr(MF, UID, OutContext);
1301 Value = MCBinaryExpr::CreateSub(Value, Base, OutContext);
1306 assert(Value && "Unknown entry kind!");
1308 unsigned EntrySize =
1309 MJTI->getEntrySize(*TM.getDataLayout());
1310 OutStreamer.EmitValue(Value, EntrySize);
1314 /// EmitSpecialLLVMGlobal - Check to see if the specified global is a
1315 /// special global used by LLVM. If so, emit it and return true, otherwise
1316 /// do nothing and return false.
1317 bool AsmPrinter::EmitSpecialLLVMGlobal(const GlobalVariable *GV) {
1318 if (GV->getName() == "llvm.used") {
1319 if (MAI->hasNoDeadStrip()) // No need to emit this at all.
1320 EmitLLVMUsedList(cast<ConstantArray>(GV->getInitializer()));
1324 // Ignore debug and non-emitted data. This handles llvm.compiler.used.
1325 if (StringRef(GV->getSection()) == "llvm.metadata" ||
1326 GV->hasAvailableExternallyLinkage())
1329 if (!GV->hasAppendingLinkage()) return false;
1331 assert(GV->hasInitializer() && "Not a special LLVM global!");
1333 if (GV->getName() == "llvm.global_ctors") {
1334 EmitXXStructorList(GV->getInitializer(), /* isCtor */ true);
1336 if (TM.getRelocationModel() == Reloc::Static &&
1337 MAI->hasStaticCtorDtorReferenceInStaticMode()) {
1338 StringRef Sym(".constructors_used");
1339 OutStreamer.EmitSymbolAttribute(OutContext.GetOrCreateSymbol(Sym),
1345 if (GV->getName() == "llvm.global_dtors") {
1346 EmitXXStructorList(GV->getInitializer(), /* isCtor */ false);
1348 if (TM.getRelocationModel() == Reloc::Static &&
1349 MAI->hasStaticCtorDtorReferenceInStaticMode()) {
1350 StringRef Sym(".destructors_used");
1351 OutStreamer.EmitSymbolAttribute(OutContext.GetOrCreateSymbol(Sym),
1360 /// EmitLLVMUsedList - For targets that define a MAI::UsedDirective, mark each
1361 /// global in the specified llvm.used list for which emitUsedDirectiveFor
1362 /// is true, as being used with this directive.
1363 void AsmPrinter::EmitLLVMUsedList(const ConstantArray *InitList) {
1364 // Should be an array of 'i8*'.
1365 for (unsigned i = 0, e = InitList->getNumOperands(); i != e; ++i) {
1366 const GlobalValue *GV =
1367 dyn_cast<GlobalValue>(InitList->getOperand(i)->stripPointerCasts());
1369 OutStreamer.EmitSymbolAttribute(getSymbol(GV), MCSA_NoDeadStrip);
1375 Structor() : Priority(0), Func(nullptr), ComdatKey(nullptr) {}
1377 llvm::Constant *Func;
1378 llvm::GlobalValue *ComdatKey;
1382 /// EmitXXStructorList - Emit the ctor or dtor list taking into account the init
1384 void AsmPrinter::EmitXXStructorList(const Constant *List, bool isCtor) {
1385 // Should be an array of '{ int, void ()* }' structs. The first value is the
1387 if (!isa<ConstantArray>(List)) return;
1389 // Sanity check the structors list.
1390 const ConstantArray *InitList = dyn_cast<ConstantArray>(List);
1391 if (!InitList) return; // Not an array!
1392 StructType *ETy = dyn_cast<StructType>(InitList->getType()->getElementType());
1393 // FIXME: Only allow the 3-field form in LLVM 4.0.
1394 if (!ETy || ETy->getNumElements() < 2 || ETy->getNumElements() > 3)
1395 return; // Not an array of two or three elements!
1396 if (!isa<IntegerType>(ETy->getTypeAtIndex(0U)) ||
1397 !isa<PointerType>(ETy->getTypeAtIndex(1U))) return; // Not (int, ptr).
1398 if (ETy->getNumElements() == 3 && !isa<PointerType>(ETy->getTypeAtIndex(2U)))
1399 return; // Not (int, ptr, ptr).
1401 // Gather the structors in a form that's convenient for sorting by priority.
1402 SmallVector<Structor, 8> Structors;
1403 for (Value *O : InitList->operands()) {
1404 ConstantStruct *CS = dyn_cast<ConstantStruct>(O);
1405 if (!CS) continue; // Malformed.
1406 if (CS->getOperand(1)->isNullValue())
1407 break; // Found a null terminator, skip the rest.
1408 ConstantInt *Priority = dyn_cast<ConstantInt>(CS->getOperand(0));
1409 if (!Priority) continue; // Malformed.
1410 Structors.push_back(Structor());
1411 Structor &S = Structors.back();
1412 S.Priority = Priority->getLimitedValue(65535);
1413 S.Func = CS->getOperand(1);
1414 if (ETy->getNumElements() == 3 && !CS->getOperand(2)->isNullValue())
1415 S.ComdatKey = dyn_cast<GlobalValue>(CS->getOperand(2)->stripPointerCasts());
1418 // Emit the function pointers in the target-specific order
1419 const DataLayout *DL = TM.getDataLayout();
1420 unsigned Align = Log2_32(DL->getPointerPrefAlignment());
1421 std::stable_sort(Structors.begin(), Structors.end(),
1422 [](const Structor &L,
1423 const Structor &R) { return L.Priority < R.Priority; });
1424 for (Structor &S : Structors) {
1425 const TargetLoweringObjectFile &Obj = getObjFileLowering();
1426 const MCSymbol *KeySym = nullptr;
1427 if (GlobalValue *GV = S.ComdatKey) {
1428 if (GV->hasAvailableExternallyLinkage())
1429 // If the associated variable is available_externally, some other TU
1430 // will provide its dynamic initializer.
1433 KeySym = getSymbol(GV);
1435 const MCSection *OutputSection =
1436 (isCtor ? Obj.getStaticCtorSection(S.Priority, KeySym)
1437 : Obj.getStaticDtorSection(S.Priority, KeySym));
1438 OutStreamer.SwitchSection(OutputSection);
1439 if (OutStreamer.getCurrentSection() != OutStreamer.getPreviousSection())
1440 EmitAlignment(Align);
1441 EmitXXStructor(S.Func);
1445 void AsmPrinter::EmitModuleIdents(Module &M) {
1446 if (!MAI->hasIdentDirective())
1449 if (const NamedMDNode *NMD = M.getNamedMetadata("llvm.ident")) {
1450 for (unsigned i = 0, e = NMD->getNumOperands(); i != e; ++i) {
1451 const MDNode *N = NMD->getOperand(i);
1452 assert(N->getNumOperands() == 1 &&
1453 "llvm.ident metadata entry can have only one operand");
1454 const MDString *S = cast<MDString>(N->getOperand(0));
1455 OutStreamer.EmitIdent(S->getString());
1460 //===--------------------------------------------------------------------===//
1461 // Emission and print routines
1464 /// EmitInt8 - Emit a byte directive and value.
1466 void AsmPrinter::EmitInt8(int Value) const {
1467 OutStreamer.EmitIntValue(Value, 1);
1470 /// EmitInt16 - Emit a short directive and value.
1472 void AsmPrinter::EmitInt16(int Value) const {
1473 OutStreamer.EmitIntValue(Value, 2);
1476 /// EmitInt32 - Emit a long directive and value.
1478 void AsmPrinter::EmitInt32(int Value) const {
1479 OutStreamer.EmitIntValue(Value, 4);
1482 /// Emit something like ".long Hi-Lo" where the size in bytes of the directive
1483 /// is specified by Size and Hi/Lo specify the labels. This implicitly uses
1484 /// .set if it avoids relocations.
1485 void AsmPrinter::EmitLabelDifference(const MCSymbol *Hi, const MCSymbol *Lo,
1486 unsigned Size) const {
1487 // Get the Hi-Lo expression.
1488 const MCExpr *Diff =
1489 MCBinaryExpr::CreateSub(MCSymbolRefExpr::Create(Hi, OutContext),
1490 MCSymbolRefExpr::Create(Lo, OutContext),
1493 if (!MAI->doesSetDirectiveSuppressesReloc()) {
1494 OutStreamer.EmitValue(Diff, Size);
1498 // Otherwise, emit with .set (aka assignment).
1499 MCSymbol *SetLabel = GetTempSymbol("set", SetCounter++);
1500 OutStreamer.EmitAssignment(SetLabel, Diff);
1501 OutStreamer.EmitSymbolValue(SetLabel, Size);
1504 /// EmitLabelPlusOffset - Emit something like ".long Label+Offset"
1505 /// where the size in bytes of the directive is specified by Size and Label
1506 /// specifies the label. This implicitly uses .set if it is available.
1507 void AsmPrinter::EmitLabelPlusOffset(const MCSymbol *Label, uint64_t Offset,
1509 bool IsSectionRelative) const {
1510 if (MAI->needsDwarfSectionOffsetDirective() && IsSectionRelative) {
1511 OutStreamer.EmitCOFFSecRel32(Label);
1515 // Emit Label+Offset (or just Label if Offset is zero)
1516 const MCExpr *Expr = MCSymbolRefExpr::Create(Label, OutContext);
1518 Expr = MCBinaryExpr::CreateAdd(
1519 Expr, MCConstantExpr::Create(Offset, OutContext), OutContext);
1521 OutStreamer.EmitValue(Expr, Size);
1524 //===----------------------------------------------------------------------===//
1526 // EmitAlignment - Emit an alignment directive to the specified power of
1527 // two boundary. For example, if you pass in 3 here, you will get an 8
1528 // byte alignment. If a global value is specified, and if that global has
1529 // an explicit alignment requested, it will override the alignment request
1530 // if required for correctness.
1532 void AsmPrinter::EmitAlignment(unsigned NumBits, const GlobalObject *GV) const {
1534 NumBits = getGVAlignmentLog2(GV, *TM.getDataLayout(),
1537 if (NumBits == 0) return; // 1-byte aligned: no need to emit alignment.
1540 static_cast<unsigned>(std::numeric_limits<unsigned>::digits) &&
1541 "undefined behavior");
1542 if (getCurrentSection()->getKind().isText())
1543 OutStreamer.EmitCodeAlignment(1u << NumBits);
1545 OutStreamer.EmitValueToAlignment(1u << NumBits);
1548 //===----------------------------------------------------------------------===//
1549 // Constant emission.
1550 //===----------------------------------------------------------------------===//
1552 const MCExpr *AsmPrinter::lowerConstant(const Constant *CV) {
1553 MCContext &Ctx = OutContext;
1555 if (CV->isNullValue() || isa<UndefValue>(CV))
1556 return MCConstantExpr::Create(0, Ctx);
1558 if (const ConstantInt *CI = dyn_cast<ConstantInt>(CV))
1559 return MCConstantExpr::Create(CI->getZExtValue(), Ctx);
1561 if (const GlobalValue *GV = dyn_cast<GlobalValue>(CV))
1562 return MCSymbolRefExpr::Create(getSymbol(GV), Ctx);
1564 if (const BlockAddress *BA = dyn_cast<BlockAddress>(CV))
1565 return MCSymbolRefExpr::Create(GetBlockAddressSymbol(BA), Ctx);
1567 const ConstantExpr *CE = dyn_cast<ConstantExpr>(CV);
1569 llvm_unreachable("Unknown constant value to lower!");
1572 if (const MCExpr *RelocExpr
1573 = getObjFileLowering().getExecutableRelativeSymbol(CE, *Mang, TM))
1576 switch (CE->getOpcode()) {
1578 // If the code isn't optimized, there may be outstanding folding
1579 // opportunities. Attempt to fold the expression using DataLayout as a
1580 // last resort before giving up.
1581 if (Constant *C = ConstantFoldConstantExpression(
1582 CE, TM.getDataLayout()))
1584 return lowerConstant(C);
1586 // Otherwise report the problem to the user.
1589 raw_string_ostream OS(S);
1590 OS << "Unsupported expression in static initializer: ";
1591 CE->printAsOperand(OS, /*PrintType=*/false,
1592 !MF ? nullptr : MF->getFunction()->getParent());
1593 report_fatal_error(OS.str());
1595 case Instruction::GetElementPtr: {
1596 const DataLayout &DL = *TM.getDataLayout();
1598 // Generate a symbolic expression for the byte address
1599 APInt OffsetAI(DL.getPointerTypeSizeInBits(CE->getType()), 0);
1600 cast<GEPOperator>(CE)->accumulateConstantOffset(DL, OffsetAI);
1602 const MCExpr *Base = lowerConstant(CE->getOperand(0));
1606 int64_t Offset = OffsetAI.getSExtValue();
1607 return MCBinaryExpr::CreateAdd(Base, MCConstantExpr::Create(Offset, Ctx),
1611 case Instruction::Trunc:
1612 // We emit the value and depend on the assembler to truncate the generated
1613 // expression properly. This is important for differences between
1614 // blockaddress labels. Since the two labels are in the same function, it
1615 // is reasonable to treat their delta as a 32-bit value.
1617 case Instruction::BitCast:
1618 return lowerConstant(CE->getOperand(0));
1620 case Instruction::IntToPtr: {
1621 const DataLayout &DL = *TM.getDataLayout();
1623 // Handle casts to pointers by changing them into casts to the appropriate
1624 // integer type. This promotes constant folding and simplifies this code.
1625 Constant *Op = CE->getOperand(0);
1626 Op = ConstantExpr::getIntegerCast(Op, DL.getIntPtrType(CV->getType()),
1628 return lowerConstant(Op);
1631 case Instruction::PtrToInt: {
1632 const DataLayout &DL = *TM.getDataLayout();
1634 // Support only foldable casts to/from pointers that can be eliminated by
1635 // changing the pointer to the appropriately sized integer type.
1636 Constant *Op = CE->getOperand(0);
1637 Type *Ty = CE->getType();
1639 const MCExpr *OpExpr = lowerConstant(Op);
1641 // We can emit the pointer value into this slot if the slot is an
1642 // integer slot equal to the size of the pointer.
1643 if (DL.getTypeAllocSize(Ty) == DL.getTypeAllocSize(Op->getType()))
1646 // Otherwise the pointer is smaller than the resultant integer, mask off
1647 // the high bits so we are sure to get a proper truncation if the input is
1649 unsigned InBits = DL.getTypeAllocSizeInBits(Op->getType());
1650 const MCExpr *MaskExpr = MCConstantExpr::Create(~0ULL >> (64-InBits), Ctx);
1651 return MCBinaryExpr::CreateAnd(OpExpr, MaskExpr, Ctx);
1654 // The MC library also has a right-shift operator, but it isn't consistently
1655 // signed or unsigned between different targets.
1656 case Instruction::Add:
1657 case Instruction::Sub:
1658 case Instruction::Mul:
1659 case Instruction::SDiv:
1660 case Instruction::SRem:
1661 case Instruction::Shl:
1662 case Instruction::And:
1663 case Instruction::Or:
1664 case Instruction::Xor: {
1665 const MCExpr *LHS = lowerConstant(CE->getOperand(0));
1666 const MCExpr *RHS = lowerConstant(CE->getOperand(1));
1667 switch (CE->getOpcode()) {
1668 default: llvm_unreachable("Unknown binary operator constant cast expr");
1669 case Instruction::Add: return MCBinaryExpr::CreateAdd(LHS, RHS, Ctx);
1670 case Instruction::Sub: return MCBinaryExpr::CreateSub(LHS, RHS, Ctx);
1671 case Instruction::Mul: return MCBinaryExpr::CreateMul(LHS, RHS, Ctx);
1672 case Instruction::SDiv: return MCBinaryExpr::CreateDiv(LHS, RHS, Ctx);
1673 case Instruction::SRem: return MCBinaryExpr::CreateMod(LHS, RHS, Ctx);
1674 case Instruction::Shl: return MCBinaryExpr::CreateShl(LHS, RHS, Ctx);
1675 case Instruction::And: return MCBinaryExpr::CreateAnd(LHS, RHS, Ctx);
1676 case Instruction::Or: return MCBinaryExpr::CreateOr (LHS, RHS, Ctx);
1677 case Instruction::Xor: return MCBinaryExpr::CreateXor(LHS, RHS, Ctx);
1683 static void emitGlobalConstantImpl(const Constant *C, AsmPrinter &AP);
1685 /// isRepeatedByteSequence - Determine whether the given value is
1686 /// composed of a repeated sequence of identical bytes and return the
1687 /// byte value. If it is not a repeated sequence, return -1.
1688 static int isRepeatedByteSequence(const ConstantDataSequential *V) {
1689 StringRef Data = V->getRawDataValues();
1690 assert(!Data.empty() && "Empty aggregates should be CAZ node");
1692 for (unsigned i = 1, e = Data.size(); i != e; ++i)
1693 if (Data[i] != C) return -1;
1694 return static_cast<uint8_t>(C); // Ensure 255 is not returned as -1.
1698 /// isRepeatedByteSequence - Determine whether the given value is
1699 /// composed of a repeated sequence of identical bytes and return the
1700 /// byte value. If it is not a repeated sequence, return -1.
1701 static int isRepeatedByteSequence(const Value *V, TargetMachine &TM) {
1703 if (const ConstantInt *CI = dyn_cast<ConstantInt>(V)) {
1704 if (CI->getBitWidth() > 64) return -1;
1707 TM.getDataLayout()->getTypeAllocSize(V->getType());
1708 uint64_t Value = CI->getZExtValue();
1710 // Make sure the constant is at least 8 bits long and has a power
1711 // of 2 bit width. This guarantees the constant bit width is
1712 // always a multiple of 8 bits, avoiding issues with padding out
1713 // to Size and other such corner cases.
1714 if (CI->getBitWidth() < 8 || !isPowerOf2_64(CI->getBitWidth())) return -1;
1716 uint8_t Byte = static_cast<uint8_t>(Value);
1718 for (unsigned i = 1; i < Size; ++i) {
1720 if (static_cast<uint8_t>(Value) != Byte) return -1;
1724 if (const ConstantArray *CA = dyn_cast<ConstantArray>(V)) {
1725 // Make sure all array elements are sequences of the same repeated
1727 assert(CA->getNumOperands() != 0 && "Should be a CAZ");
1728 int Byte = isRepeatedByteSequence(CA->getOperand(0), TM);
1729 if (Byte == -1) return -1;
1731 for (unsigned i = 1, e = CA->getNumOperands(); i != e; ++i) {
1732 int ThisByte = isRepeatedByteSequence(CA->getOperand(i), TM);
1733 if (ThisByte == -1) return -1;
1734 if (Byte != ThisByte) return -1;
1739 if (const ConstantDataSequential *CDS = dyn_cast<ConstantDataSequential>(V))
1740 return isRepeatedByteSequence(CDS);
1745 static void emitGlobalConstantDataSequential(const ConstantDataSequential *CDS,
1748 // See if we can aggregate this into a .fill, if so, emit it as such.
1749 int Value = isRepeatedByteSequence(CDS, AP.TM);
1752 AP.TM.getDataLayout()->getTypeAllocSize(
1754 // Don't emit a 1-byte object as a .fill.
1756 return AP.OutStreamer.EmitFill(Bytes, Value);
1759 // If this can be emitted with .ascii/.asciz, emit it as such.
1760 if (CDS->isString())
1761 return AP.OutStreamer.EmitBytes(CDS->getAsString());
1763 // Otherwise, emit the values in successive locations.
1764 unsigned ElementByteSize = CDS->getElementByteSize();
1765 if (isa<IntegerType>(CDS->getElementType())) {
1766 for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i) {
1768 AP.OutStreamer.GetCommentOS() << format("0x%" PRIx64 "\n",
1769 CDS->getElementAsInteger(i));
1770 AP.OutStreamer.EmitIntValue(CDS->getElementAsInteger(i),
1773 } else if (ElementByteSize == 4) {
1774 // FP Constants are printed as integer constants to avoid losing
1776 assert(CDS->getElementType()->isFloatTy());
1777 for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i) {
1783 F = CDS->getElementAsFloat(i);
1785 AP.OutStreamer.GetCommentOS() << "float " << F << '\n';
1786 AP.OutStreamer.EmitIntValue(I, 4);
1789 assert(CDS->getElementType()->isDoubleTy());
1790 for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i) {
1796 F = CDS->getElementAsDouble(i);
1798 AP.OutStreamer.GetCommentOS() << "double " << F << '\n';
1799 AP.OutStreamer.EmitIntValue(I, 8);
1803 const DataLayout &DL = *AP.TM.getDataLayout();
1804 unsigned Size = DL.getTypeAllocSize(CDS->getType());
1805 unsigned EmittedSize = DL.getTypeAllocSize(CDS->getType()->getElementType()) *
1806 CDS->getNumElements();
1807 if (unsigned Padding = Size - EmittedSize)
1808 AP.OutStreamer.EmitZeros(Padding);
1812 static void emitGlobalConstantArray(const ConstantArray *CA, AsmPrinter &AP) {
1813 // See if we can aggregate some values. Make sure it can be
1814 // represented as a series of bytes of the constant value.
1815 int Value = isRepeatedByteSequence(CA, AP.TM);
1819 AP.TM.getDataLayout()->getTypeAllocSize(
1821 AP.OutStreamer.EmitFill(Bytes, Value);
1824 for (unsigned i = 0, e = CA->getNumOperands(); i != e; ++i)
1825 emitGlobalConstantImpl(CA->getOperand(i), AP);
1829 static void emitGlobalConstantVector(const ConstantVector *CV, AsmPrinter &AP) {
1830 for (unsigned i = 0, e = CV->getType()->getNumElements(); i != e; ++i)
1831 emitGlobalConstantImpl(CV->getOperand(i), AP);
1833 const DataLayout &DL = *AP.TM.getDataLayout();
1834 unsigned Size = DL.getTypeAllocSize(CV->getType());
1835 unsigned EmittedSize = DL.getTypeAllocSize(CV->getType()->getElementType()) *
1836 CV->getType()->getNumElements();
1837 if (unsigned Padding = Size - EmittedSize)
1838 AP.OutStreamer.EmitZeros(Padding);
1841 static void emitGlobalConstantStruct(const ConstantStruct *CS, AsmPrinter &AP) {
1842 // Print the fields in successive locations. Pad to align if needed!
1843 const DataLayout *DL = AP.TM.getDataLayout();
1844 unsigned Size = DL->getTypeAllocSize(CS->getType());
1845 const StructLayout *Layout = DL->getStructLayout(CS->getType());
1846 uint64_t SizeSoFar = 0;
1847 for (unsigned i = 0, e = CS->getNumOperands(); i != e; ++i) {
1848 const Constant *Field = CS->getOperand(i);
1850 // Check if padding is needed and insert one or more 0s.
1851 uint64_t FieldSize = DL->getTypeAllocSize(Field->getType());
1852 uint64_t PadSize = ((i == e-1 ? Size : Layout->getElementOffset(i+1))
1853 - Layout->getElementOffset(i)) - FieldSize;
1854 SizeSoFar += FieldSize + PadSize;
1856 // Now print the actual field value.
1857 emitGlobalConstantImpl(Field, AP);
1859 // Insert padding - this may include padding to increase the size of the
1860 // current field up to the ABI size (if the struct is not packed) as well
1861 // as padding to ensure that the next field starts at the right offset.
1862 AP.OutStreamer.EmitZeros(PadSize);
1864 assert(SizeSoFar == Layout->getSizeInBytes() &&
1865 "Layout of constant struct may be incorrect!");
1868 static void emitGlobalConstantFP(const ConstantFP *CFP, AsmPrinter &AP) {
1869 APInt API = CFP->getValueAPF().bitcastToAPInt();
1871 // First print a comment with what we think the original floating-point value
1872 // should have been.
1873 if (AP.isVerbose()) {
1874 SmallString<8> StrVal;
1875 CFP->getValueAPF().toString(StrVal);
1878 CFP->getType()->print(AP.OutStreamer.GetCommentOS());
1880 AP.OutStreamer.GetCommentOS() << "Printing <null> Type";
1881 AP.OutStreamer.GetCommentOS() << ' ' << StrVal << '\n';
1884 // Now iterate through the APInt chunks, emitting them in endian-correct
1885 // order, possibly with a smaller chunk at beginning/end (e.g. for x87 80-bit
1887 unsigned NumBytes = API.getBitWidth() / 8;
1888 unsigned TrailingBytes = NumBytes % sizeof(uint64_t);
1889 const uint64_t *p = API.getRawData();
1891 // PPC's long double has odd notions of endianness compared to how LLVM
1892 // handles it: p[0] goes first for *big* endian on PPC.
1893 if (AP.TM.getDataLayout()->isBigEndian() &&
1894 !CFP->getType()->isPPC_FP128Ty()) {
1895 int Chunk = API.getNumWords() - 1;
1898 AP.OutStreamer.EmitIntValue(p[Chunk--], TrailingBytes);
1900 for (; Chunk >= 0; --Chunk)
1901 AP.OutStreamer.EmitIntValue(p[Chunk], sizeof(uint64_t));
1904 for (Chunk = 0; Chunk < NumBytes / sizeof(uint64_t); ++Chunk)
1905 AP.OutStreamer.EmitIntValue(p[Chunk], sizeof(uint64_t));
1908 AP.OutStreamer.EmitIntValue(p[Chunk], TrailingBytes);
1911 // Emit the tail padding for the long double.
1912 const DataLayout &DL = *AP.TM.getDataLayout();
1913 AP.OutStreamer.EmitZeros(DL.getTypeAllocSize(CFP->getType()) -
1914 DL.getTypeStoreSize(CFP->getType()));
1917 static void emitGlobalConstantLargeInt(const ConstantInt *CI, AsmPrinter &AP) {
1918 const DataLayout *DL = AP.TM.getDataLayout();
1919 unsigned BitWidth = CI->getBitWidth();
1921 // Copy the value as we may massage the layout for constants whose bit width
1922 // is not a multiple of 64-bits.
1923 APInt Realigned(CI->getValue());
1924 uint64_t ExtraBits = 0;
1925 unsigned ExtraBitsSize = BitWidth & 63;
1927 if (ExtraBitsSize) {
1928 // The bit width of the data is not a multiple of 64-bits.
1929 // The extra bits are expected to be at the end of the chunk of the memory.
1931 // * Nothing to be done, just record the extra bits to emit.
1933 // * Record the extra bits to emit.
1934 // * Realign the raw data to emit the chunks of 64-bits.
1935 if (DL->isBigEndian()) {
1936 // Basically the structure of the raw data is a chunk of 64-bits cells:
1937 // 0 1 BitWidth / 64
1938 // [chunk1][chunk2] ... [chunkN].
1939 // The most significant chunk is chunkN and it should be emitted first.
1940 // However, due to the alignment issue chunkN contains useless bits.
1941 // Realign the chunks so that they contain only useless information:
1942 // ExtraBits 0 1 (BitWidth / 64) - 1
1943 // chu[nk1 chu][nk2 chu] ... [nkN-1 chunkN]
1944 ExtraBits = Realigned.getRawData()[0] &
1945 (((uint64_t)-1) >> (64 - ExtraBitsSize));
1946 Realigned = Realigned.lshr(ExtraBitsSize);
1948 ExtraBits = Realigned.getRawData()[BitWidth / 64];
1951 // We don't expect assemblers to support integer data directives
1952 // for more than 64 bits, so we emit the data in at most 64-bit
1953 // quantities at a time.
1954 const uint64_t *RawData = Realigned.getRawData();
1955 for (unsigned i = 0, e = BitWidth / 64; i != e; ++i) {
1956 uint64_t Val = DL->isBigEndian() ? RawData[e - i - 1] : RawData[i];
1957 AP.OutStreamer.EmitIntValue(Val, 8);
1960 if (ExtraBitsSize) {
1961 // Emit the extra bits after the 64-bits chunks.
1963 // Emit a directive that fills the expected size.
1964 uint64_t Size = AP.TM.getDataLayout()->getTypeAllocSize(
1966 Size -= (BitWidth / 64) * 8;
1967 assert(Size && Size * 8 >= ExtraBitsSize &&
1968 (ExtraBits & (((uint64_t)-1) >> (64 - ExtraBitsSize)))
1969 == ExtraBits && "Directive too small for extra bits.");
1970 AP.OutStreamer.EmitIntValue(ExtraBits, Size);
1974 static void emitGlobalConstantImpl(const Constant *CV, AsmPrinter &AP) {
1975 const DataLayout *DL = AP.TM.getDataLayout();
1976 uint64_t Size = DL->getTypeAllocSize(CV->getType());
1977 if (isa<ConstantAggregateZero>(CV) || isa<UndefValue>(CV))
1978 return AP.OutStreamer.EmitZeros(Size);
1980 if (const ConstantInt *CI = dyn_cast<ConstantInt>(CV)) {
1987 AP.OutStreamer.GetCommentOS() << format("0x%" PRIx64 "\n",
1988 CI->getZExtValue());
1989 AP.OutStreamer.EmitIntValue(CI->getZExtValue(), Size);
1992 emitGlobalConstantLargeInt(CI, AP);
1997 if (const ConstantFP *CFP = dyn_cast<ConstantFP>(CV))
1998 return emitGlobalConstantFP(CFP, AP);
2000 if (isa<ConstantPointerNull>(CV)) {
2001 AP.OutStreamer.EmitIntValue(0, Size);
2005 if (const ConstantDataSequential *CDS = dyn_cast<ConstantDataSequential>(CV))
2006 return emitGlobalConstantDataSequential(CDS, AP);
2008 if (const ConstantArray *CVA = dyn_cast<ConstantArray>(CV))
2009 return emitGlobalConstantArray(CVA, AP);
2011 if (const ConstantStruct *CVS = dyn_cast<ConstantStruct>(CV))
2012 return emitGlobalConstantStruct(CVS, AP);
2014 if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(CV)) {
2015 // Look through bitcasts, which might not be able to be MCExpr'ized (e.g. of
2017 if (CE->getOpcode() == Instruction::BitCast)
2018 return emitGlobalConstantImpl(CE->getOperand(0), AP);
2021 // If the constant expression's size is greater than 64-bits, then we have
2022 // to emit the value in chunks. Try to constant fold the value and emit it
2024 Constant *New = ConstantFoldConstantExpression(CE, DL);
2025 if (New && New != CE)
2026 return emitGlobalConstantImpl(New, AP);
2030 if (const ConstantVector *V = dyn_cast<ConstantVector>(CV))
2031 return emitGlobalConstantVector(V, AP);
2033 // Otherwise, it must be a ConstantExpr. Lower it to an MCExpr, then emit it
2034 // thread the streamer with EmitValue.
2035 AP.OutStreamer.EmitValue(AP.lowerConstant(CV), Size);
2038 /// EmitGlobalConstant - Print a general LLVM constant to the .s file.
2039 void AsmPrinter::EmitGlobalConstant(const Constant *CV) {
2041 TM.getDataLayout()->getTypeAllocSize(CV->getType());
2043 emitGlobalConstantImpl(CV, *this);
2044 else if (MAI->hasSubsectionsViaSymbols()) {
2045 // If the global has zero size, emit a single byte so that two labels don't
2046 // look like they are at the same location.
2047 OutStreamer.EmitIntValue(0, 1);
2051 void AsmPrinter::EmitMachineConstantPoolValue(MachineConstantPoolValue *MCPV) {
2052 // Target doesn't support this yet!
2053 llvm_unreachable("Target does not support EmitMachineConstantPoolValue");
2056 void AsmPrinter::printOffset(int64_t Offset, raw_ostream &OS) const {
2058 OS << '+' << Offset;
2059 else if (Offset < 0)
2063 //===----------------------------------------------------------------------===//
2064 // Symbol Lowering Routines.
2065 //===----------------------------------------------------------------------===//
2067 /// GetTempSymbol - Return the MCSymbol corresponding to the assembler
2068 /// temporary label with the specified stem and unique ID.
2069 MCSymbol *AsmPrinter::GetTempSymbol(const Twine &Name, unsigned ID) const {
2070 const DataLayout *DL = TM.getDataLayout();
2071 return OutContext.GetOrCreateSymbol(Twine(DL->getPrivateGlobalPrefix()) +
2075 /// GetTempSymbol - Return an assembler temporary label with the specified
2077 MCSymbol *AsmPrinter::GetTempSymbol(const Twine &Name) const {
2078 const DataLayout *DL = TM.getDataLayout();
2079 return OutContext.GetOrCreateSymbol(Twine(DL->getPrivateGlobalPrefix())+
2084 MCSymbol *AsmPrinter::GetBlockAddressSymbol(const BlockAddress *BA) const {
2085 return MMI->getAddrLabelSymbol(BA->getBasicBlock());
2088 MCSymbol *AsmPrinter::GetBlockAddressSymbol(const BasicBlock *BB) const {
2089 return MMI->getAddrLabelSymbol(BB);
2092 /// GetCPISymbol - Return the symbol for the specified constant pool entry.
2093 MCSymbol *AsmPrinter::GetCPISymbol(unsigned CPID) const {
2094 const DataLayout *DL = TM.getDataLayout();
2095 return OutContext.GetOrCreateSymbol
2096 (Twine(DL->getPrivateGlobalPrefix()) + "CPI" + Twine(getFunctionNumber())
2097 + "_" + Twine(CPID));
2100 /// GetJTISymbol - Return the symbol for the specified jump table entry.
2101 MCSymbol *AsmPrinter::GetJTISymbol(unsigned JTID, bool isLinkerPrivate) const {
2102 return MF->getJTISymbol(JTID, OutContext, isLinkerPrivate);
2105 /// GetJTSetSymbol - Return the symbol for the specified jump table .set
2106 /// FIXME: privatize to AsmPrinter.
2107 MCSymbol *AsmPrinter::GetJTSetSymbol(unsigned UID, unsigned MBBID) const {
2108 const DataLayout *DL = TM.getDataLayout();
2109 return OutContext.GetOrCreateSymbol
2110 (Twine(DL->getPrivateGlobalPrefix()) + Twine(getFunctionNumber()) + "_" +
2111 Twine(UID) + "_set_" + Twine(MBBID));
2114 MCSymbol *AsmPrinter::getSymbolWithGlobalValueBase(const GlobalValue *GV,
2115 StringRef Suffix) const {
2116 return getObjFileLowering().getSymbolWithGlobalValueBase(GV, Suffix, *Mang,
2120 /// GetExternalSymbolSymbol - Return the MCSymbol for the specified
2122 MCSymbol *AsmPrinter::GetExternalSymbolSymbol(StringRef Sym) const {
2123 SmallString<60> NameStr;
2124 Mang->getNameWithPrefix(NameStr, Sym);
2125 return OutContext.GetOrCreateSymbol(NameStr.str());
2130 /// PrintParentLoopComment - Print comments about parent loops of this one.
2131 static void PrintParentLoopComment(raw_ostream &OS, const MachineLoop *Loop,
2132 unsigned FunctionNumber) {
2134 PrintParentLoopComment(OS, Loop->getParentLoop(), FunctionNumber);
2135 OS.indent(Loop->getLoopDepth()*2)
2136 << "Parent Loop BB" << FunctionNumber << "_"
2137 << Loop->getHeader()->getNumber()
2138 << " Depth=" << Loop->getLoopDepth() << '\n';
2142 /// PrintChildLoopComment - Print comments about child loops within
2143 /// the loop for this basic block, with nesting.
2144 static void PrintChildLoopComment(raw_ostream &OS, const MachineLoop *Loop,
2145 unsigned FunctionNumber) {
2146 // Add child loop information
2147 for (const MachineLoop *CL : *Loop) {
2148 OS.indent(CL->getLoopDepth()*2)
2149 << "Child Loop BB" << FunctionNumber << "_"
2150 << CL->getHeader()->getNumber() << " Depth " << CL->getLoopDepth()
2152 PrintChildLoopComment(OS, CL, FunctionNumber);
2156 /// emitBasicBlockLoopComments - Pretty-print comments for basic blocks.
2157 static void emitBasicBlockLoopComments(const MachineBasicBlock &MBB,
2158 const MachineLoopInfo *LI,
2159 const AsmPrinter &AP) {
2160 // Add loop depth information
2161 const MachineLoop *Loop = LI->getLoopFor(&MBB);
2164 MachineBasicBlock *Header = Loop->getHeader();
2165 assert(Header && "No header for loop");
2167 // If this block is not a loop header, just print out what is the loop header
2169 if (Header != &MBB) {
2170 AP.OutStreamer.AddComment(" in Loop: Header=BB" +
2171 Twine(AP.getFunctionNumber())+"_" +
2172 Twine(Loop->getHeader()->getNumber())+
2173 " Depth="+Twine(Loop->getLoopDepth()));
2177 // Otherwise, it is a loop header. Print out information about child and
2179 raw_ostream &OS = AP.OutStreamer.GetCommentOS();
2181 PrintParentLoopComment(OS, Loop->getParentLoop(), AP.getFunctionNumber());
2184 OS.indent(Loop->getLoopDepth()*2-2);
2189 OS << "Loop Header: Depth=" + Twine(Loop->getLoopDepth()) << '\n';
2191 PrintChildLoopComment(OS, Loop, AP.getFunctionNumber());
2195 /// EmitBasicBlockStart - This method prints the label for the specified
2196 /// MachineBasicBlock, an alignment (if present) and a comment describing
2197 /// it if appropriate.
2198 void AsmPrinter::EmitBasicBlockStart(const MachineBasicBlock &MBB) const {
2199 // Emit an alignment directive for this block, if needed.
2200 if (unsigned Align = MBB.getAlignment())
2201 EmitAlignment(Align);
2203 // If the block has its address taken, emit any labels that were used to
2204 // reference the block. It is possible that there is more than one label
2205 // here, because multiple LLVM BB's may have been RAUW'd to this block after
2206 // the references were generated.
2207 if (MBB.hasAddressTaken()) {
2208 const BasicBlock *BB = MBB.getBasicBlock();
2210 OutStreamer.AddComment("Block address taken");
2212 std::vector<MCSymbol*> Symbols = MMI->getAddrLabelSymbolToEmit(BB);
2213 for (auto *Sym : Symbols)
2214 OutStreamer.EmitLabel(Sym);
2217 // Print some verbose block comments.
2219 if (const BasicBlock *BB = MBB.getBasicBlock())
2221 OutStreamer.AddComment("%" + BB->getName());
2222 emitBasicBlockLoopComments(MBB, LI, *this);
2225 // Print the main label for the block.
2226 if (MBB.pred_empty() || isBlockOnlyReachableByFallthrough(&MBB)) {
2228 // NOTE: Want this comment at start of line, don't emit with AddComment.
2229 OutStreamer.emitRawComment(" BB#" + Twine(MBB.getNumber()) + ":", false);
2232 OutStreamer.EmitLabel(MBB.getSymbol());
2236 void AsmPrinter::EmitVisibility(MCSymbol *Sym, unsigned Visibility,
2237 bool IsDefinition) const {
2238 MCSymbolAttr Attr = MCSA_Invalid;
2240 switch (Visibility) {
2242 case GlobalValue::HiddenVisibility:
2244 Attr = MAI->getHiddenVisibilityAttr();
2246 Attr = MAI->getHiddenDeclarationVisibilityAttr();
2248 case GlobalValue::ProtectedVisibility:
2249 Attr = MAI->getProtectedVisibilityAttr();
2253 if (Attr != MCSA_Invalid)
2254 OutStreamer.EmitSymbolAttribute(Sym, Attr);
2257 /// isBlockOnlyReachableByFallthough - Return true if the basic block has
2258 /// exactly one predecessor and the control transfer mechanism between
2259 /// the predecessor and this block is a fall-through.
2261 isBlockOnlyReachableByFallthrough(const MachineBasicBlock *MBB) const {
2262 // If this is a landing pad, it isn't a fall through. If it has no preds,
2263 // then nothing falls through to it.
2264 if (MBB->isLandingPad() || MBB->pred_empty())
2267 // If there isn't exactly one predecessor, it can't be a fall through.
2268 if (MBB->pred_size() > 1)
2271 // The predecessor has to be immediately before this block.
2272 MachineBasicBlock *Pred = *MBB->pred_begin();
2273 if (!Pred->isLayoutSuccessor(MBB))
2276 // If the block is completely empty, then it definitely does fall through.
2280 // Check the terminators in the previous blocks
2281 for (const auto &MI : Pred->terminators()) {
2282 // If it is not a simple branch, we are in a table somewhere.
2283 if (!MI.isBranch() || MI.isIndirectBranch())
2286 // If we are the operands of one of the branches, this is not a fall
2287 // through. Note that targets with delay slots will usually bundle
2288 // terminators with the delay slot instruction.
2289 for (ConstMIBundleOperands OP(&MI); OP.isValid(); ++OP) {
2292 if (OP->isMBB() && OP->getMBB() == MBB)
2302 GCMetadataPrinter *AsmPrinter::GetOrCreateGCPrinter(GCStrategy &S) {
2303 if (!S.usesMetadata())
2306 assert(!S.useStatepoints() && "statepoints do not currently support custom"
2307 " stackmap formats, please see the documentation for a description of"
2308 " the default format. If you really need a custom serialized format,"
2309 " please file a bug");
2311 gcp_map_type &GCMap = getGCMap(GCMetadataPrinters);
2312 gcp_map_type::iterator GCPI = GCMap.find(&S);
2313 if (GCPI != GCMap.end())
2314 return GCPI->second.get();
2316 const char *Name = S.getName().c_str();
2318 for (GCMetadataPrinterRegistry::iterator
2319 I = GCMetadataPrinterRegistry::begin(),
2320 E = GCMetadataPrinterRegistry::end(); I != E; ++I)
2321 if (strcmp(Name, I->getName()) == 0) {
2322 std::unique_ptr<GCMetadataPrinter> GMP = I->instantiate();
2324 auto IterBool = GCMap.insert(std::make_pair(&S, std::move(GMP)));
2325 return IterBool.first->second.get();
2328 report_fatal_error("no GCMetadataPrinter registered for GC: " + Twine(Name));
2331 /// Pin vtable to this file.
2332 AsmPrinterHandler::~AsmPrinterHandler() {}