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 "WinException.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/MachineModuleInfoImpls.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/MC/MCValue.h"
45 #include "llvm/Support/ErrorHandling.h"
46 #include "llvm/Support/Format.h"
47 #include "llvm/Support/MathExtras.h"
48 #include "llvm/Support/TargetRegistry.h"
49 #include "llvm/Support/Timer.h"
50 #include "llvm/Target/TargetFrameLowering.h"
51 #include "llvm/Target/TargetInstrInfo.h"
52 #include "llvm/Target/TargetLowering.h"
53 #include "llvm/Target/TargetLoweringObjectFile.h"
54 #include "llvm/Target/TargetRegisterInfo.h"
55 #include "llvm/Target/TargetSubtargetInfo.h"
58 #define DEBUG_TYPE "asm-printer"
60 static const char *const DWARFGroupName = "DWARF Emission";
61 static const char *const DbgTimerName = "Debug Info Emission";
62 static const char *const EHTimerName = "DWARF Exception Writer";
63 static const char *const CodeViewLineTablesGroupName = "CodeView Line Tables";
65 STATISTIC(EmittedInsts, "Number of machine instrs printed");
67 char AsmPrinter::ID = 0;
69 typedef DenseMap<GCStrategy*, std::unique_ptr<GCMetadataPrinter>> gcp_map_type;
70 static gcp_map_type &getGCMap(void *&P) {
72 P = new gcp_map_type();
73 return *(gcp_map_type*)P;
77 /// getGVAlignmentLog2 - Return the alignment to use for the specified global
78 /// value in log2 form. This rounds up to the preferred alignment if possible
80 static unsigned getGVAlignmentLog2(const GlobalValue *GV, const DataLayout &DL,
81 unsigned InBits = 0) {
83 if (const GlobalVariable *GVar = dyn_cast<GlobalVariable>(GV))
84 NumBits = DL.getPreferredAlignmentLog(GVar);
86 // If InBits is specified, round it to it.
90 // If the GV has a specified alignment, take it into account.
91 if (GV->getAlignment() == 0)
94 unsigned GVAlign = Log2_32(GV->getAlignment());
96 // If the GVAlign is larger than NumBits, or if we are required to obey
97 // NumBits because the GV has an assigned section, obey it.
98 if (GVAlign > NumBits || GV->hasSection())
103 AsmPrinter::AsmPrinter(TargetMachine &tm, std::unique_ptr<MCStreamer> Streamer)
104 : MachineFunctionPass(ID), TM(tm), MAI(tm.getMCAsmInfo()),
105 OutContext(Streamer->getContext()), OutStreamer(std::move(Streamer)),
106 LastMI(nullptr), LastFn(0), Counter(~0U) {
111 CurExceptionSym = CurrentFnSym = CurrentFnSymForSize = nullptr;
112 CurrentFnBegin = nullptr;
113 CurrentFnEnd = nullptr;
114 GCMetadataPrinters = nullptr;
115 VerboseAsm = OutStreamer->isVerboseAsm();
118 AsmPrinter::~AsmPrinter() {
119 assert(!DD && Handlers.empty() && "Debug/EH info didn't get finalized");
121 if (GCMetadataPrinters) {
122 gcp_map_type &GCMap = getGCMap(GCMetadataPrinters);
125 GCMetadataPrinters = nullptr;
129 /// getFunctionNumber - Return a unique ID for the current function.
131 unsigned AsmPrinter::getFunctionNumber() const {
132 return MF->getFunctionNumber();
135 const TargetLoweringObjectFile &AsmPrinter::getObjFileLowering() const {
136 return *TM.getObjFileLowering();
139 /// getDataLayout - Return information about data layout.
140 const DataLayout &AsmPrinter::getDataLayout() const {
141 return *TM.getDataLayout();
144 const MCSubtargetInfo &AsmPrinter::getSubtargetInfo() const {
145 assert(MF && "getSubtargetInfo requires a valid MachineFunction!");
146 return MF->getSubtarget<MCSubtargetInfo>();
149 void AsmPrinter::EmitToStreamer(MCStreamer &S, const MCInst &Inst) {
150 S.EmitInstruction(Inst, getSubtargetInfo());
153 StringRef AsmPrinter::getTargetTriple() const {
154 return TM.getTargetTriple();
157 /// getCurrentSection() - Return the current section we are emitting to.
158 const MCSection *AsmPrinter::getCurrentSection() const {
159 return OutStreamer->getCurrentSection().first;
164 void AsmPrinter::getAnalysisUsage(AnalysisUsage &AU) const {
165 AU.setPreservesAll();
166 MachineFunctionPass::getAnalysisUsage(AU);
167 AU.addRequired<MachineModuleInfo>();
168 AU.addRequired<GCModuleInfo>();
170 AU.addRequired<MachineLoopInfo>();
173 bool AsmPrinter::doInitialization(Module &M) {
174 MMI = getAnalysisIfAvailable<MachineModuleInfo>();
175 MMI->AnalyzeModule(M);
177 // Initialize TargetLoweringObjectFile.
178 const_cast<TargetLoweringObjectFile&>(getObjFileLowering())
179 .Initialize(OutContext, TM);
181 OutStreamer->InitSections(false);
183 Mang = new Mangler(TM.getDataLayout());
185 // Emit the version-min deplyment target directive if needed.
187 // FIXME: If we end up with a collection of these sorts of Darwin-specific
188 // or ELF-specific things, it may make sense to have a platform helper class
189 // that will work with the target helper class. For now keep it here, as the
190 // alternative is duplicated code in each of the target asm printers that
191 // use the directive, where it would need the same conditionalization
193 Triple TT(getTargetTriple());
194 if (TT.isOSDarwin()) {
195 unsigned Major, Minor, Update;
196 TT.getOSVersion(Major, Minor, Update);
197 // If there is a version specified, Major will be non-zero.
199 OutStreamer->EmitVersionMin((TT.isMacOSX() ?
200 MCVM_OSXVersionMin : MCVM_IOSVersionMin),
201 Major, Minor, Update);
204 // Allow the target to emit any magic that it wants at the start of the file.
205 EmitStartOfAsmFile(M);
207 // Very minimal debug info. It is ignored if we emit actual debug info. If we
208 // don't, this at least helps the user find where a global came from.
209 if (MAI->hasSingleParameterDotFile()) {
211 OutStreamer->EmitFileDirective(M.getModuleIdentifier());
214 GCModuleInfo *MI = getAnalysisIfAvailable<GCModuleInfo>();
215 assert(MI && "AsmPrinter didn't require GCModuleInfo?");
217 if (GCMetadataPrinter *MP = GetOrCreateGCPrinter(*I))
218 MP->beginAssembly(M, *MI, *this);
220 // Emit module-level inline asm if it exists.
221 if (!M.getModuleInlineAsm().empty()) {
222 // We're at the module level. Construct MCSubtarget from the default CPU
223 // and target triple.
224 std::unique_ptr<MCSubtargetInfo> STI(TM.getTarget().createMCSubtargetInfo(
225 TM.getTargetTriple(), TM.getTargetCPU(), TM.getTargetFeatureString()));
226 OutStreamer->AddComment("Start of file scope inline assembly");
227 OutStreamer->AddBlankLine();
228 EmitInlineAsm(M.getModuleInlineAsm()+"\n", *STI, TM.Options.MCOptions);
229 OutStreamer->AddComment("End of file scope inline assembly");
230 OutStreamer->AddBlankLine();
233 if (MAI->doesSupportDebugInformation()) {
234 bool skip_dwarf = false;
235 if (Triple(TM.getTargetTriple()).isKnownWindowsMSVCEnvironment()) {
236 Handlers.push_back(HandlerInfo(new WinCodeViewLineTables(this),
238 CodeViewLineTablesGroupName));
239 // FIXME: Don't emit DWARF debug info if there's at least one function
240 // with AddressSanitizer instrumentation.
241 // This is a band-aid fix for PR22032.
242 for (auto &F : M.functions()) {
243 if (F.hasFnAttribute(Attribute::SanitizeAddress)) {
250 DD = new DwarfDebug(this, &M);
251 Handlers.push_back(HandlerInfo(DD, DbgTimerName, DWARFGroupName));
255 EHStreamer *ES = nullptr;
256 switch (MAI->getExceptionHandlingType()) {
257 case ExceptionHandling::None:
259 case ExceptionHandling::SjLj:
260 case ExceptionHandling::DwarfCFI:
261 ES = new DwarfCFIException(this);
263 case ExceptionHandling::ARM:
264 ES = new ARMException(this);
266 case ExceptionHandling::WinEH:
267 switch (MAI->getWinEHEncodingType()) {
268 default: llvm_unreachable("unsupported unwinding information encoding");
269 case WinEH::EncodingType::Invalid:
271 case WinEH::EncodingType::X86:
272 case WinEH::EncodingType::Itanium:
273 ES = new WinException(this);
279 Handlers.push_back(HandlerInfo(ES, EHTimerName, DWARFGroupName));
283 static bool canBeHidden(const GlobalValue *GV, const MCAsmInfo &MAI) {
284 if (!MAI.hasWeakDefCanBeHiddenDirective())
287 return canBeOmittedFromSymbolTable(GV);
290 void AsmPrinter::EmitLinkage(const GlobalValue *GV, MCSymbol *GVSym) const {
291 GlobalValue::LinkageTypes Linkage = GV->getLinkage();
293 case GlobalValue::CommonLinkage:
294 case GlobalValue::LinkOnceAnyLinkage:
295 case GlobalValue::LinkOnceODRLinkage:
296 case GlobalValue::WeakAnyLinkage:
297 case GlobalValue::WeakODRLinkage:
298 if (MAI->hasWeakDefDirective()) {
300 OutStreamer->EmitSymbolAttribute(GVSym, MCSA_Global);
302 if (!canBeHidden(GV, *MAI))
303 // .weak_definition _foo
304 OutStreamer->EmitSymbolAttribute(GVSym, MCSA_WeakDefinition);
306 OutStreamer->EmitSymbolAttribute(GVSym, MCSA_WeakDefAutoPrivate);
307 } else if (MAI->hasLinkOnceDirective()) {
309 OutStreamer->EmitSymbolAttribute(GVSym, MCSA_Global);
310 //NOTE: linkonce is handled by the section the symbol was assigned to.
313 OutStreamer->EmitSymbolAttribute(GVSym, MCSA_Weak);
316 case GlobalValue::AppendingLinkage:
317 // FIXME: appending linkage variables should go into a section of
318 // their name or something. For now, just emit them as external.
319 case GlobalValue::ExternalLinkage:
320 // If external or appending, declare as a global symbol.
322 OutStreamer->EmitSymbolAttribute(GVSym, MCSA_Global);
324 case GlobalValue::PrivateLinkage:
325 case GlobalValue::InternalLinkage:
327 case GlobalValue::AvailableExternallyLinkage:
328 llvm_unreachable("Should never emit this");
329 case GlobalValue::ExternalWeakLinkage:
330 llvm_unreachable("Don't know how to emit these");
332 llvm_unreachable("Unknown linkage type!");
335 void AsmPrinter::getNameWithPrefix(SmallVectorImpl<char> &Name,
336 const GlobalValue *GV) const {
337 TM.getNameWithPrefix(Name, GV, *Mang);
340 MCSymbol *AsmPrinter::getSymbol(const GlobalValue *GV) const {
341 return TM.getSymbol(GV, *Mang);
344 /// EmitGlobalVariable - Emit the specified global variable to the .s file.
345 void AsmPrinter::EmitGlobalVariable(const GlobalVariable *GV) {
346 if (GV->hasInitializer()) {
347 // Check to see if this is a special global used by LLVM, if so, emit it.
348 if (EmitSpecialLLVMGlobal(GV))
351 // Skip the emission of global equivalents. The symbol can be emitted later
352 // on by emitGlobalGOTEquivs in case it turns out to be needed.
353 if (GlobalGOTEquivs.count(getSymbol(GV)))
357 GV->printAsOperand(OutStreamer->GetCommentOS(),
358 /*PrintType=*/false, GV->getParent());
359 OutStreamer->GetCommentOS() << '\n';
363 MCSymbol *GVSym = getSymbol(GV);
364 EmitVisibility(GVSym, GV->getVisibility(), !GV->isDeclaration());
366 if (!GV->hasInitializer()) // External globals require no extra code.
369 GVSym->redefineIfPossible();
370 if (GVSym->isDefined() || GVSym->isVariable())
371 report_fatal_error("symbol '" + Twine(GVSym->getName()) +
372 "' is already defined");
374 if (MAI->hasDotTypeDotSizeDirective())
375 OutStreamer->EmitSymbolAttribute(GVSym, MCSA_ELF_TypeObject);
377 SectionKind GVKind = TargetLoweringObjectFile::getKindForGlobal(GV, TM);
379 const DataLayout *DL = TM.getDataLayout();
380 uint64_t Size = DL->getTypeAllocSize(GV->getType()->getElementType());
382 // If the alignment is specified, we *must* obey it. Overaligning a global
383 // with a specified alignment is a prompt way to break globals emitted to
384 // sections and expected to be contiguous (e.g. ObjC metadata).
385 unsigned AlignLog = getGVAlignmentLog2(GV, *DL);
387 for (const HandlerInfo &HI : Handlers) {
388 NamedRegionTimer T(HI.TimerName, HI.TimerGroupName, TimePassesIsEnabled);
389 HI.Handler->setSymbolSize(GVSym, Size);
392 // Handle common and BSS local symbols (.lcomm).
393 if (GVKind.isCommon() || GVKind.isBSSLocal()) {
394 if (Size == 0) Size = 1; // .comm Foo, 0 is undefined, avoid it.
395 unsigned Align = 1 << AlignLog;
397 // Handle common symbols.
398 if (GVKind.isCommon()) {
399 if (!getObjFileLowering().getCommDirectiveSupportsAlignment())
403 OutStreamer->EmitCommonSymbol(GVSym, Size, Align);
407 // Handle local BSS symbols.
408 if (MAI->hasMachoZeroFillDirective()) {
409 MCSection *TheSection =
410 getObjFileLowering().SectionForGlobal(GV, GVKind, *Mang, TM);
411 // .zerofill __DATA, __bss, _foo, 400, 5
412 OutStreamer->EmitZerofill(TheSection, GVSym, Size, Align);
416 // Use .lcomm only if it supports user-specified alignment.
417 // Otherwise, while it would still be correct to use .lcomm in some
418 // cases (e.g. when Align == 1), the external assembler might enfore
419 // some -unknown- default alignment behavior, which could cause
420 // spurious differences between external and integrated assembler.
421 // Prefer to simply fall back to .local / .comm in this case.
422 if (MAI->getLCOMMDirectiveAlignmentType() != LCOMM::NoAlignment) {
424 OutStreamer->EmitLocalCommonSymbol(GVSym, Size, Align);
428 if (!getObjFileLowering().getCommDirectiveSupportsAlignment())
432 OutStreamer->EmitSymbolAttribute(GVSym, MCSA_Local);
434 OutStreamer->EmitCommonSymbol(GVSym, Size, Align);
438 MCSection *TheSection =
439 getObjFileLowering().SectionForGlobal(GV, GVKind, *Mang, TM);
441 // Handle the zerofill directive on darwin, which is a special form of BSS
443 if (GVKind.isBSSExtern() && MAI->hasMachoZeroFillDirective()) {
444 if (Size == 0) Size = 1; // zerofill of 0 bytes is undefined.
447 OutStreamer->EmitSymbolAttribute(GVSym, MCSA_Global);
448 // .zerofill __DATA, __common, _foo, 400, 5
449 OutStreamer->EmitZerofill(TheSection, GVSym, Size, 1 << AlignLog);
453 // Handle thread local data for mach-o which requires us to output an
454 // additional structure of data and mangle the original symbol so that we
455 // can reference it later.
457 // TODO: This should become an "emit thread local global" method on TLOF.
458 // All of this macho specific stuff should be sunk down into TLOFMachO and
459 // stuff like "TLSExtraDataSection" should no longer be part of the parent
460 // TLOF class. This will also make it more obvious that stuff like
461 // MCStreamer::EmitTBSSSymbol is macho specific and only called from macho
463 if (GVKind.isThreadLocal() && MAI->hasMachoTBSSDirective()) {
464 // Emit the .tbss symbol
466 OutContext.getOrCreateSymbol(GVSym->getName() + Twine("$tlv$init"));
468 if (GVKind.isThreadBSS()) {
469 TheSection = getObjFileLowering().getTLSBSSSection();
470 OutStreamer->EmitTBSSSymbol(TheSection, MangSym, Size, 1 << AlignLog);
471 } else if (GVKind.isThreadData()) {
472 OutStreamer->SwitchSection(TheSection);
474 EmitAlignment(AlignLog, GV);
475 OutStreamer->EmitLabel(MangSym);
477 EmitGlobalConstant(GV->getInitializer());
480 OutStreamer->AddBlankLine();
482 // Emit the variable struct for the runtime.
483 MCSection *TLVSect = getObjFileLowering().getTLSExtraDataSection();
485 OutStreamer->SwitchSection(TLVSect);
486 // Emit the linkage here.
487 EmitLinkage(GV, GVSym);
488 OutStreamer->EmitLabel(GVSym);
490 // Three pointers in size:
491 // - __tlv_bootstrap - used to make sure support exists
492 // - spare pointer, used when mapped by the runtime
493 // - pointer to mangled symbol above with initializer
494 unsigned PtrSize = DL->getPointerTypeSize(GV->getType());
495 OutStreamer->EmitSymbolValue(GetExternalSymbolSymbol("_tlv_bootstrap"),
497 OutStreamer->EmitIntValue(0, PtrSize);
498 OutStreamer->EmitSymbolValue(MangSym, PtrSize);
500 OutStreamer->AddBlankLine();
504 OutStreamer->SwitchSection(TheSection);
506 EmitLinkage(GV, GVSym);
507 EmitAlignment(AlignLog, GV);
509 OutStreamer->EmitLabel(GVSym);
511 EmitGlobalConstant(GV->getInitializer());
513 if (MAI->hasDotTypeDotSizeDirective())
515 OutStreamer->EmitELFSize(GVSym, MCConstantExpr::Create(Size, OutContext));
517 OutStreamer->AddBlankLine();
520 /// EmitFunctionHeader - This method emits the header for the current
522 void AsmPrinter::EmitFunctionHeader() {
523 // Print out constants referenced by the function
526 // Print the 'header' of function.
527 const Function *F = MF->getFunction();
529 OutStreamer->SwitchSection(
530 getObjFileLowering().SectionForGlobal(F, *Mang, TM));
531 EmitVisibility(CurrentFnSym, F->getVisibility());
533 EmitLinkage(F, CurrentFnSym);
534 if (MAI->hasFunctionAlignment())
535 EmitAlignment(MF->getAlignment(), F);
537 if (MAI->hasDotTypeDotSizeDirective())
538 OutStreamer->EmitSymbolAttribute(CurrentFnSym, MCSA_ELF_TypeFunction);
541 F->printAsOperand(OutStreamer->GetCommentOS(),
542 /*PrintType=*/false, F->getParent());
543 OutStreamer->GetCommentOS() << '\n';
546 // Emit the prefix data.
547 if (F->hasPrefixData())
548 EmitGlobalConstant(F->getPrefixData());
550 // Emit the CurrentFnSym. This is a virtual function to allow targets to
551 // do their wild and crazy things as required.
552 EmitFunctionEntryLabel();
554 // If the function had address-taken blocks that got deleted, then we have
555 // references to the dangling symbols. Emit them at the start of the function
556 // so that we don't get references to undefined symbols.
557 std::vector<MCSymbol*> DeadBlockSyms;
558 MMI->takeDeletedSymbolsForFunction(F, DeadBlockSyms);
559 for (unsigned i = 0, e = DeadBlockSyms.size(); i != e; ++i) {
560 OutStreamer->AddComment("Address taken block that was later removed");
561 OutStreamer->EmitLabel(DeadBlockSyms[i]);
564 if (CurrentFnBegin) {
565 if (MAI->useAssignmentForEHBegin()) {
566 MCSymbol *CurPos = OutContext.createTempSymbol();
567 OutStreamer->EmitLabel(CurPos);
568 OutStreamer->EmitAssignment(CurrentFnBegin,
569 MCSymbolRefExpr::Create(CurPos, OutContext));
571 OutStreamer->EmitLabel(CurrentFnBegin);
575 // Emit pre-function debug and/or EH information.
576 for (const HandlerInfo &HI : Handlers) {
577 NamedRegionTimer T(HI.TimerName, HI.TimerGroupName, TimePassesIsEnabled);
578 HI.Handler->beginFunction(MF);
581 // Emit the prologue data.
582 if (F->hasPrologueData())
583 EmitGlobalConstant(F->getPrologueData());
586 /// EmitFunctionEntryLabel - Emit the label that is the entrypoint for the
587 /// function. This can be overridden by targets as required to do custom stuff.
588 void AsmPrinter::EmitFunctionEntryLabel() {
589 CurrentFnSym->redefineIfPossible();
591 // The function label could have already been emitted if two symbols end up
592 // conflicting due to asm renaming. Detect this and emit an error.
593 if (CurrentFnSym->isVariable())
594 report_fatal_error("'" + Twine(CurrentFnSym->getName()) +
595 "' is a protected alias");
596 if (CurrentFnSym->isDefined())
597 report_fatal_error("'" + Twine(CurrentFnSym->getName()) +
598 "' label emitted multiple times to assembly file");
600 return OutStreamer->EmitLabel(CurrentFnSym);
603 /// emitComments - Pretty-print comments for instructions.
604 static void emitComments(const MachineInstr &MI, raw_ostream &CommentOS) {
605 const MachineFunction *MF = MI.getParent()->getParent();
606 const TargetInstrInfo *TII = MF->getSubtarget().getInstrInfo();
608 // Check for spills and reloads
611 const MachineFrameInfo *FrameInfo = MF->getFrameInfo();
613 // We assume a single instruction only has a spill or reload, not
615 const MachineMemOperand *MMO;
616 if (TII->isLoadFromStackSlotPostFE(&MI, FI)) {
617 if (FrameInfo->isSpillSlotObjectIndex(FI)) {
618 MMO = *MI.memoperands_begin();
619 CommentOS << MMO->getSize() << "-byte Reload\n";
621 } else if (TII->hasLoadFromStackSlot(&MI, MMO, FI)) {
622 if (FrameInfo->isSpillSlotObjectIndex(FI))
623 CommentOS << MMO->getSize() << "-byte Folded Reload\n";
624 } else if (TII->isStoreToStackSlotPostFE(&MI, FI)) {
625 if (FrameInfo->isSpillSlotObjectIndex(FI)) {
626 MMO = *MI.memoperands_begin();
627 CommentOS << MMO->getSize() << "-byte Spill\n";
629 } else if (TII->hasStoreToStackSlot(&MI, MMO, FI)) {
630 if (FrameInfo->isSpillSlotObjectIndex(FI))
631 CommentOS << MMO->getSize() << "-byte Folded Spill\n";
634 // Check for spill-induced copies
635 if (MI.getAsmPrinterFlag(MachineInstr::ReloadReuse))
636 CommentOS << " Reload Reuse\n";
639 /// emitImplicitDef - This method emits the specified machine instruction
640 /// that is an implicit def.
641 void AsmPrinter::emitImplicitDef(const MachineInstr *MI) const {
642 unsigned RegNo = MI->getOperand(0).getReg();
643 OutStreamer->AddComment(Twine("implicit-def: ") +
644 MMI->getContext().getRegisterInfo()->getName(RegNo));
645 OutStreamer->AddBlankLine();
648 static void emitKill(const MachineInstr *MI, AsmPrinter &AP) {
649 std::string Str = "kill:";
650 for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
651 const MachineOperand &Op = MI->getOperand(i);
652 assert(Op.isReg() && "KILL instruction must have only register operands");
654 Str += AP.MMI->getContext().getRegisterInfo()->getName(Op.getReg());
655 Str += (Op.isDef() ? "<def>" : "<kill>");
657 AP.OutStreamer->AddComment(Str);
658 AP.OutStreamer->AddBlankLine();
661 /// emitDebugValueComment - This method handles the target-independent form
662 /// of DBG_VALUE, returning true if it was able to do so. A false return
663 /// means the target will need to handle MI in EmitInstruction.
664 static bool emitDebugValueComment(const MachineInstr *MI, AsmPrinter &AP) {
665 // This code handles only the 4-operand target-independent form.
666 if (MI->getNumOperands() != 4)
669 SmallString<128> Str;
670 raw_svector_ostream OS(Str);
671 OS << "DEBUG_VALUE: ";
673 const DILocalVariable *V = MI->getDebugVariable();
674 if (auto *SP = dyn_cast<DISubprogram>(V->getScope())) {
675 StringRef Name = SP->getDisplayName();
681 const DIExpression *Expr = MI->getDebugExpression();
682 if (Expr->isBitPiece())
683 OS << " [bit_piece offset=" << Expr->getBitPieceOffset()
684 << " size=" << Expr->getBitPieceSize() << "]";
687 // The second operand is only an offset if it's an immediate.
688 bool Deref = MI->getOperand(0).isReg() && MI->getOperand(1).isImm();
689 int64_t Offset = Deref ? MI->getOperand(1).getImm() : 0;
691 // Register or immediate value. Register 0 means undef.
692 if (MI->getOperand(0).isFPImm()) {
693 APFloat APF = APFloat(MI->getOperand(0).getFPImm()->getValueAPF());
694 if (MI->getOperand(0).getFPImm()->getType()->isFloatTy()) {
695 OS << (double)APF.convertToFloat();
696 } else if (MI->getOperand(0).getFPImm()->getType()->isDoubleTy()) {
697 OS << APF.convertToDouble();
699 // There is no good way to print long double. Convert a copy to
700 // double. Ah well, it's only a comment.
702 APF.convert(APFloat::IEEEdouble, APFloat::rmNearestTiesToEven,
704 OS << "(long double) " << APF.convertToDouble();
706 } else if (MI->getOperand(0).isImm()) {
707 OS << MI->getOperand(0).getImm();
708 } else if (MI->getOperand(0).isCImm()) {
709 MI->getOperand(0).getCImm()->getValue().print(OS, false /*isSigned*/);
712 if (MI->getOperand(0).isReg()) {
713 Reg = MI->getOperand(0).getReg();
715 assert(MI->getOperand(0).isFI() && "Unknown operand type");
716 const TargetFrameLowering *TFI = AP.MF->getSubtarget().getFrameLowering();
717 Offset += TFI->getFrameIndexReference(*AP.MF,
718 MI->getOperand(0).getIndex(), Reg);
722 // Suppress offset, it is not meaningful here.
724 // NOTE: Want this comment at start of line, don't emit with AddComment.
725 AP.OutStreamer->emitRawComment(OS.str());
730 OS << AP.MMI->getContext().getRegisterInfo()->getName(Reg);
734 OS << '+' << Offset << ']';
736 // NOTE: Want this comment at start of line, don't emit with AddComment.
737 AP.OutStreamer->emitRawComment(OS.str());
741 AsmPrinter::CFIMoveType AsmPrinter::needsCFIMoves() {
742 if (MAI->getExceptionHandlingType() == ExceptionHandling::DwarfCFI &&
743 MF->getFunction()->needsUnwindTableEntry())
746 if (MMI->hasDebugInfo())
752 bool AsmPrinter::needsSEHMoves() {
753 return MAI->usesWindowsCFI() && MF->getFunction()->needsUnwindTableEntry();
756 void AsmPrinter::emitCFIInstruction(const MachineInstr &MI) {
757 ExceptionHandling ExceptionHandlingType = MAI->getExceptionHandlingType();
758 if (ExceptionHandlingType != ExceptionHandling::DwarfCFI &&
759 ExceptionHandlingType != ExceptionHandling::ARM)
762 if (needsCFIMoves() == CFI_M_None)
765 const MachineModuleInfo &MMI = MF->getMMI();
766 const std::vector<MCCFIInstruction> &Instrs = MMI.getFrameInstructions();
767 unsigned CFIIndex = MI.getOperand(0).getCFIIndex();
768 const MCCFIInstruction &CFI = Instrs[CFIIndex];
769 emitCFIInstruction(CFI);
772 void AsmPrinter::emitFrameAlloc(const MachineInstr &MI) {
773 // The operands are the MCSymbol and the frame offset of the allocation.
774 MCSymbol *FrameAllocSym = MI.getOperand(0).getMCSymbol();
775 int FrameOffset = MI.getOperand(1).getImm();
777 // Emit a symbol assignment.
778 OutStreamer->EmitAssignment(FrameAllocSym,
779 MCConstantExpr::Create(FrameOffset, OutContext));
782 /// EmitFunctionBody - This method emits the body and trailer for a
784 void AsmPrinter::EmitFunctionBody() {
785 EmitFunctionHeader();
787 // Emit target-specific gunk before the function body.
788 EmitFunctionBodyStart();
790 bool ShouldPrintDebugScopes = MMI->hasDebugInfo();
792 // Print out code for the function.
793 bool HasAnyRealCode = false;
794 for (auto &MBB : *MF) {
795 // Print a label for the basic block.
796 EmitBasicBlockStart(MBB);
797 for (auto &MI : MBB) {
799 // Print the assembly for the instruction.
800 if (!MI.isPosition() && !MI.isImplicitDef() && !MI.isKill() &&
801 !MI.isDebugValue()) {
802 HasAnyRealCode = true;
806 if (ShouldPrintDebugScopes) {
807 for (const HandlerInfo &HI : Handlers) {
808 NamedRegionTimer T(HI.TimerName, HI.TimerGroupName,
809 TimePassesIsEnabled);
810 HI.Handler->beginInstruction(&MI);
815 emitComments(MI, OutStreamer->GetCommentOS());
817 switch (MI.getOpcode()) {
818 case TargetOpcode::CFI_INSTRUCTION:
819 emitCFIInstruction(MI);
822 case TargetOpcode::FRAME_ALLOC:
826 case TargetOpcode::EH_LABEL:
827 case TargetOpcode::GC_LABEL:
828 OutStreamer->EmitLabel(MI.getOperand(0).getMCSymbol());
830 case TargetOpcode::INLINEASM:
833 case TargetOpcode::DBG_VALUE:
835 if (!emitDebugValueComment(&MI, *this))
836 EmitInstruction(&MI);
839 case TargetOpcode::IMPLICIT_DEF:
840 if (isVerbose()) emitImplicitDef(&MI);
842 case TargetOpcode::KILL:
843 if (isVerbose()) emitKill(&MI, *this);
846 EmitInstruction(&MI);
850 if (ShouldPrintDebugScopes) {
851 for (const HandlerInfo &HI : Handlers) {
852 NamedRegionTimer T(HI.TimerName, HI.TimerGroupName,
853 TimePassesIsEnabled);
854 HI.Handler->endInstruction();
859 EmitBasicBlockEnd(MBB);
862 // If the function is empty and the object file uses .subsections_via_symbols,
863 // then we need to emit *something* to the function body to prevent the
864 // labels from collapsing together. Just emit a noop.
865 if ((MAI->hasSubsectionsViaSymbols() && !HasAnyRealCode)) {
867 MF->getSubtarget().getInstrInfo()->getNoopForMachoTarget(Noop);
868 OutStreamer->AddComment("avoids zero-length function");
870 // Targets can opt-out of emitting the noop here by leaving the opcode
872 if (Noop.getOpcode())
873 OutStreamer->EmitInstruction(Noop, getSubtargetInfo());
876 const Function *F = MF->getFunction();
877 for (const auto &BB : *F) {
878 if (!BB.hasAddressTaken())
880 MCSymbol *Sym = GetBlockAddressSymbol(&BB);
881 if (Sym->isDefined())
883 OutStreamer->AddComment("Address of block that was removed by CodeGen");
884 OutStreamer->EmitLabel(Sym);
887 // Emit target-specific gunk after the function body.
888 EmitFunctionBodyEnd();
890 if (!MMI->getLandingPads().empty() || MMI->hasDebugInfo() ||
891 MAI->hasDotTypeDotSizeDirective()) {
892 // Create a symbol for the end of function.
893 CurrentFnEnd = createTempSymbol("func_end");
894 OutStreamer->EmitLabel(CurrentFnEnd);
897 // If the target wants a .size directive for the size of the function, emit
899 if (MAI->hasDotTypeDotSizeDirective()) {
900 // We can get the size as difference between the function label and the
902 const MCExpr *SizeExp =
903 MCBinaryExpr::CreateSub(MCSymbolRefExpr::Create(CurrentFnEnd, OutContext),
904 MCSymbolRefExpr::Create(CurrentFnSymForSize,
907 OutStreamer->EmitELFSize(CurrentFnSym, SizeExp);
910 for (const HandlerInfo &HI : Handlers) {
911 NamedRegionTimer T(HI.TimerName, HI.TimerGroupName, TimePassesIsEnabled);
912 HI.Handler->markFunctionEnd();
915 // Print out jump tables referenced by the function.
918 // Emit post-function debug and/or EH information.
919 for (const HandlerInfo &HI : Handlers) {
920 NamedRegionTimer T(HI.TimerName, HI.TimerGroupName, TimePassesIsEnabled);
921 HI.Handler->endFunction(MF);
925 OutStreamer->AddBlankLine();
928 /// \brief Compute the number of Global Variables that uses a Constant.
929 static unsigned getNumGlobalVariableUses(const Constant *C) {
933 if (isa<GlobalVariable>(C))
936 unsigned NumUses = 0;
937 for (auto *CU : C->users())
938 NumUses += getNumGlobalVariableUses(dyn_cast<Constant>(CU));
943 /// \brief Only consider global GOT equivalents if at least one user is a
944 /// cstexpr inside an initializer of another global variables. Also, don't
945 /// handle cstexpr inside instructions. During global variable emission,
946 /// candidates are skipped and are emitted later in case at least one cstexpr
947 /// isn't replaced by a PC relative GOT entry access.
948 static bool isGOTEquivalentCandidate(const GlobalVariable *GV,
949 unsigned &NumGOTEquivUsers) {
950 // Global GOT equivalents are unnamed private globals with a constant
951 // pointer initializer to another global symbol. They must point to a
952 // GlobalVariable or Function, i.e., as GlobalValue.
953 if (!GV->hasUnnamedAddr() || !GV->hasInitializer() || !GV->isConstant() ||
954 !GV->isDiscardableIfUnused() || !dyn_cast<GlobalValue>(GV->getOperand(0)))
957 // To be a got equivalent, at least one of its users need to be a constant
958 // expression used by another global variable.
959 for (auto *U : GV->users())
960 NumGOTEquivUsers += getNumGlobalVariableUses(dyn_cast<Constant>(U));
962 return NumGOTEquivUsers > 0;
965 /// \brief Unnamed constant global variables solely contaning a pointer to
966 /// another globals variable is equivalent to a GOT table entry; it contains the
967 /// the address of another symbol. Optimize it and replace accesses to these
968 /// "GOT equivalents" by using the GOT entry for the final global instead.
969 /// Compute GOT equivalent candidates among all global variables to avoid
970 /// emitting them if possible later on, after it use is replaced by a GOT entry
972 void AsmPrinter::computeGlobalGOTEquivs(Module &M) {
973 if (!getObjFileLowering().supportIndirectSymViaGOTPCRel())
976 for (const auto &G : M.globals()) {
977 unsigned NumGOTEquivUsers = 0;
978 if (!isGOTEquivalentCandidate(&G, NumGOTEquivUsers))
981 const MCSymbol *GOTEquivSym = getSymbol(&G);
982 GlobalGOTEquivs[GOTEquivSym] = std::make_pair(&G, NumGOTEquivUsers);
986 /// \brief Constant expressions using GOT equivalent globals may not be eligible
987 /// for PC relative GOT entry conversion, in such cases we need to emit such
988 /// globals we previously omitted in EmitGlobalVariable.
989 void AsmPrinter::emitGlobalGOTEquivs() {
990 if (!getObjFileLowering().supportIndirectSymViaGOTPCRel())
993 SmallVector<const GlobalVariable *, 8> FailedCandidates;
994 for (auto &I : GlobalGOTEquivs) {
995 const GlobalVariable *GV = I.second.first;
996 unsigned Cnt = I.second.second;
998 FailedCandidates.push_back(GV);
1000 GlobalGOTEquivs.clear();
1002 for (auto *GV : FailedCandidates)
1003 EmitGlobalVariable(GV);
1006 bool AsmPrinter::doFinalization(Module &M) {
1007 // Set the MachineFunction to nullptr so that we can catch attempted
1008 // accesses to MF specific features at the module level and so that
1009 // we can conditionalize accesses based on whether or not it is nullptr.
1012 // Gather all GOT equivalent globals in the module. We really need two
1013 // passes over the globals: one to compute and another to avoid its emission
1014 // in EmitGlobalVariable, otherwise we would not be able to handle cases
1015 // where the got equivalent shows up before its use.
1016 computeGlobalGOTEquivs(M);
1018 // Emit global variables.
1019 for (const auto &G : M.globals())
1020 EmitGlobalVariable(&G);
1022 // Emit remaining GOT equivalent globals.
1023 emitGlobalGOTEquivs();
1025 // Emit visibility info for declarations
1026 for (const Function &F : M) {
1027 if (!F.isDeclaration())
1029 GlobalValue::VisibilityTypes V = F.getVisibility();
1030 if (V == GlobalValue::DefaultVisibility)
1033 MCSymbol *Name = getSymbol(&F);
1034 EmitVisibility(Name, V, false);
1037 const TargetLoweringObjectFile &TLOF = getObjFileLowering();
1039 // Emit module flags.
1040 SmallVector<Module::ModuleFlagEntry, 8> ModuleFlags;
1041 M.getModuleFlagsMetadata(ModuleFlags);
1042 if (!ModuleFlags.empty())
1043 TLOF.emitModuleFlags(*OutStreamer, ModuleFlags, *Mang, TM);
1045 Triple TT(TM.getTargetTriple());
1046 if (TT.isOSBinFormatELF()) {
1047 MachineModuleInfoELF &MMIELF = MMI->getObjFileInfo<MachineModuleInfoELF>();
1049 // Output stubs for external and common global variables.
1050 MachineModuleInfoELF::SymbolListTy Stubs = MMIELF.GetGVStubList();
1051 if (!Stubs.empty()) {
1052 OutStreamer->SwitchSection(TLOF.getDataRelSection());
1053 const DataLayout *DL = TM.getDataLayout();
1055 for (const auto &Stub : Stubs) {
1056 OutStreamer->EmitLabel(Stub.first);
1057 OutStreamer->EmitSymbolValue(Stub.second.getPointer(),
1058 DL->getPointerSize());
1063 // Make sure we wrote out everything we need.
1064 OutStreamer->Flush();
1066 // Finalize debug and EH information.
1067 for (const HandlerInfo &HI : Handlers) {
1068 NamedRegionTimer T(HI.TimerName, HI.TimerGroupName,
1069 TimePassesIsEnabled);
1070 HI.Handler->endModule();
1076 // If the target wants to know about weak references, print them all.
1077 if (MAI->getWeakRefDirective()) {
1078 // FIXME: This is not lazy, it would be nice to only print weak references
1079 // to stuff that is actually used. Note that doing so would require targets
1080 // to notice uses in operands (due to constant exprs etc). This should
1081 // happen with the MC stuff eventually.
1083 // Print out module-level global variables here.
1084 for (const auto &G : M.globals()) {
1085 if (!G.hasExternalWeakLinkage())
1087 OutStreamer->EmitSymbolAttribute(getSymbol(&G), MCSA_WeakReference);
1090 for (const auto &F : M) {
1091 if (!F.hasExternalWeakLinkage())
1093 OutStreamer->EmitSymbolAttribute(getSymbol(&F), MCSA_WeakReference);
1097 OutStreamer->AddBlankLine();
1098 for (const auto &Alias : M.aliases()) {
1099 MCSymbol *Name = getSymbol(&Alias);
1101 if (Alias.hasExternalLinkage() || !MAI->getWeakRefDirective())
1102 OutStreamer->EmitSymbolAttribute(Name, MCSA_Global);
1103 else if (Alias.hasWeakLinkage() || Alias.hasLinkOnceLinkage())
1104 OutStreamer->EmitSymbolAttribute(Name, MCSA_WeakReference);
1106 assert(Alias.hasLocalLinkage() && "Invalid alias linkage");
1108 EmitVisibility(Name, Alias.getVisibility());
1110 // Emit the directives as assignments aka .set:
1111 OutStreamer->EmitAssignment(Name, lowerConstant(Alias.getAliasee()));
1114 GCModuleInfo *MI = getAnalysisIfAvailable<GCModuleInfo>();
1115 assert(MI && "AsmPrinter didn't require GCModuleInfo?");
1116 for (GCModuleInfo::iterator I = MI->end(), E = MI->begin(); I != E; )
1117 if (GCMetadataPrinter *MP = GetOrCreateGCPrinter(**--I))
1118 MP->finishAssembly(M, *MI, *this);
1120 // Emit llvm.ident metadata in an '.ident' directive.
1121 EmitModuleIdents(M);
1123 // Emit __morestack address if needed for indirect calls.
1124 if (MMI->usesMorestackAddr()) {
1125 MCSection *ReadOnlySection =
1126 getObjFileLowering().getSectionForConstant(SectionKind::getReadOnly(),
1128 OutStreamer->SwitchSection(ReadOnlySection);
1130 MCSymbol *AddrSymbol =
1131 OutContext.getOrCreateSymbol(StringRef("__morestack_addr"));
1132 OutStreamer->EmitLabel(AddrSymbol);
1134 unsigned PtrSize = TM.getDataLayout()->getPointerSize(0);
1135 OutStreamer->EmitSymbolValue(GetExternalSymbolSymbol("__morestack"),
1139 // If we don't have any trampolines, then we don't require stack memory
1140 // to be executable. Some targets have a directive to declare this.
1141 Function *InitTrampolineIntrinsic = M.getFunction("llvm.init.trampoline");
1142 if (!InitTrampolineIntrinsic || InitTrampolineIntrinsic->use_empty())
1143 if (MCSection *S = MAI->getNonexecutableStackSection(OutContext))
1144 OutStreamer->SwitchSection(S);
1146 // Allow the target to emit any magic that it wants at the end of the file,
1147 // after everything else has gone out.
1148 EmitEndOfAsmFile(M);
1150 delete Mang; Mang = nullptr;
1153 OutStreamer->Finish();
1154 OutStreamer->reset();
1159 MCSymbol *AsmPrinter::getCurExceptionSym() {
1160 if (!CurExceptionSym)
1161 CurExceptionSym = createTempSymbol("exception");
1162 return CurExceptionSym;
1165 void AsmPrinter::SetupMachineFunction(MachineFunction &MF) {
1167 // Get the function symbol.
1168 CurrentFnSym = getSymbol(MF.getFunction());
1169 CurrentFnSymForSize = CurrentFnSym;
1170 CurrentFnBegin = nullptr;
1171 CurExceptionSym = nullptr;
1172 bool NeedsLocalForSize = MAI->needsLocalForSize();
1173 if (!MMI->getLandingPads().empty() || MMI->hasDebugInfo() ||
1174 NeedsLocalForSize) {
1175 CurrentFnBegin = createTempSymbol("func_begin");
1176 if (NeedsLocalForSize)
1177 CurrentFnSymForSize = CurrentFnBegin;
1181 LI = &getAnalysis<MachineLoopInfo>();
1185 // Keep track the alignment, constpool entries per Section.
1189 SmallVector<unsigned, 4> CPEs;
1190 SectionCPs(MCSection *s, unsigned a) : S(s), Alignment(a) {}
1194 /// EmitConstantPool - Print to the current output stream assembly
1195 /// representations of the constants in the constant pool MCP. This is
1196 /// used to print out constants which have been "spilled to memory" by
1197 /// the code generator.
1199 void AsmPrinter::EmitConstantPool() {
1200 const MachineConstantPool *MCP = MF->getConstantPool();
1201 const std::vector<MachineConstantPoolEntry> &CP = MCP->getConstants();
1202 if (CP.empty()) return;
1204 // Calculate sections for constant pool entries. We collect entries to go into
1205 // the same section together to reduce amount of section switch statements.
1206 SmallVector<SectionCPs, 4> CPSections;
1207 for (unsigned i = 0, e = CP.size(); i != e; ++i) {
1208 const MachineConstantPoolEntry &CPE = CP[i];
1209 unsigned Align = CPE.getAlignment();
1212 CPE.getSectionKind(TM.getDataLayout());
1214 const Constant *C = nullptr;
1215 if (!CPE.isMachineConstantPoolEntry())
1216 C = CPE.Val.ConstVal;
1218 MCSection *S = getObjFileLowering().getSectionForConstant(Kind, C);
1220 // The number of sections are small, just do a linear search from the
1221 // last section to the first.
1223 unsigned SecIdx = CPSections.size();
1224 while (SecIdx != 0) {
1225 if (CPSections[--SecIdx].S == S) {
1231 SecIdx = CPSections.size();
1232 CPSections.push_back(SectionCPs(S, Align));
1235 if (Align > CPSections[SecIdx].Alignment)
1236 CPSections[SecIdx].Alignment = Align;
1237 CPSections[SecIdx].CPEs.push_back(i);
1240 // Now print stuff into the calculated sections.
1241 const MCSection *CurSection = nullptr;
1242 unsigned Offset = 0;
1243 for (unsigned i = 0, e = CPSections.size(); i != e; ++i) {
1244 for (unsigned j = 0, ee = CPSections[i].CPEs.size(); j != ee; ++j) {
1245 unsigned CPI = CPSections[i].CPEs[j];
1246 MCSymbol *Sym = GetCPISymbol(CPI);
1247 if (!Sym->isUndefined())
1250 if (CurSection != CPSections[i].S) {
1251 OutStreamer->SwitchSection(CPSections[i].S);
1252 EmitAlignment(Log2_32(CPSections[i].Alignment));
1253 CurSection = CPSections[i].S;
1257 MachineConstantPoolEntry CPE = CP[CPI];
1259 // Emit inter-object padding for alignment.
1260 unsigned AlignMask = CPE.getAlignment() - 1;
1261 unsigned NewOffset = (Offset + AlignMask) & ~AlignMask;
1262 OutStreamer->EmitZeros(NewOffset - Offset);
1264 Type *Ty = CPE.getType();
1265 Offset = NewOffset +
1266 TM.getDataLayout()->getTypeAllocSize(Ty);
1268 OutStreamer->EmitLabel(Sym);
1269 if (CPE.isMachineConstantPoolEntry())
1270 EmitMachineConstantPoolValue(CPE.Val.MachineCPVal);
1272 EmitGlobalConstant(CPE.Val.ConstVal);
1277 /// EmitJumpTableInfo - Print assembly representations of the jump tables used
1278 /// by the current function to the current output stream.
1280 void AsmPrinter::EmitJumpTableInfo() {
1281 const DataLayout *DL = MF->getTarget().getDataLayout();
1282 const MachineJumpTableInfo *MJTI = MF->getJumpTableInfo();
1284 if (MJTI->getEntryKind() == MachineJumpTableInfo::EK_Inline) return;
1285 const std::vector<MachineJumpTableEntry> &JT = MJTI->getJumpTables();
1286 if (JT.empty()) return;
1288 // Pick the directive to use to print the jump table entries, and switch to
1289 // the appropriate section.
1290 const Function *F = MF->getFunction();
1291 const TargetLoweringObjectFile &TLOF = getObjFileLowering();
1292 bool JTInDiffSection = !TLOF.shouldPutJumpTableInFunctionSection(
1293 MJTI->getEntryKind() == MachineJumpTableInfo::EK_LabelDifference32,
1295 if (JTInDiffSection) {
1296 // Drop it in the readonly section.
1297 MCSection *ReadOnlySection = TLOF.getSectionForJumpTable(*F, *Mang, TM);
1298 OutStreamer->SwitchSection(ReadOnlySection);
1301 EmitAlignment(Log2_32(
1302 MJTI->getEntryAlignment(*TM.getDataLayout())));
1304 // Jump tables in code sections are marked with a data_region directive
1305 // where that's supported.
1306 if (!JTInDiffSection)
1307 OutStreamer->EmitDataRegion(MCDR_DataRegionJT32);
1309 for (unsigned JTI = 0, e = JT.size(); JTI != e; ++JTI) {
1310 const std::vector<MachineBasicBlock*> &JTBBs = JT[JTI].MBBs;
1312 // If this jump table was deleted, ignore it.
1313 if (JTBBs.empty()) continue;
1315 // For the EK_LabelDifference32 entry, if using .set avoids a relocation,
1316 /// emit a .set directive for each unique entry.
1317 if (MJTI->getEntryKind() == MachineJumpTableInfo::EK_LabelDifference32 &&
1318 MAI->doesSetDirectiveSuppressesReloc()) {
1319 SmallPtrSet<const MachineBasicBlock*, 16> EmittedSets;
1320 const TargetLowering *TLI = MF->getSubtarget().getTargetLowering();
1321 const MCExpr *Base = TLI->getPICJumpTableRelocBaseExpr(MF,JTI,OutContext);
1322 for (unsigned ii = 0, ee = JTBBs.size(); ii != ee; ++ii) {
1323 const MachineBasicBlock *MBB = JTBBs[ii];
1324 if (!EmittedSets.insert(MBB).second)
1327 // .set LJTSet, LBB32-base
1329 MCSymbolRefExpr::Create(MBB->getSymbol(), OutContext);
1330 OutStreamer->EmitAssignment(GetJTSetSymbol(JTI, MBB->getNumber()),
1331 MCBinaryExpr::CreateSub(LHS, Base,
1336 // On some targets (e.g. Darwin) we want to emit two consecutive labels
1337 // before each jump table. The first label is never referenced, but tells
1338 // the assembler and linker the extents of the jump table object. The
1339 // second label is actually referenced by the code.
1340 if (JTInDiffSection && DL->hasLinkerPrivateGlobalPrefix())
1341 // FIXME: This doesn't have to have any specific name, just any randomly
1342 // named and numbered 'l' label would work. Simplify GetJTISymbol.
1343 OutStreamer->EmitLabel(GetJTISymbol(JTI, true));
1345 OutStreamer->EmitLabel(GetJTISymbol(JTI));
1347 for (unsigned ii = 0, ee = JTBBs.size(); ii != ee; ++ii)
1348 EmitJumpTableEntry(MJTI, JTBBs[ii], JTI);
1350 if (!JTInDiffSection)
1351 OutStreamer->EmitDataRegion(MCDR_DataRegionEnd);
1354 /// EmitJumpTableEntry - Emit a jump table entry for the specified MBB to the
1356 void AsmPrinter::EmitJumpTableEntry(const MachineJumpTableInfo *MJTI,
1357 const MachineBasicBlock *MBB,
1358 unsigned UID) const {
1359 assert(MBB && MBB->getNumber() >= 0 && "Invalid basic block");
1360 const MCExpr *Value = nullptr;
1361 switch (MJTI->getEntryKind()) {
1362 case MachineJumpTableInfo::EK_Inline:
1363 llvm_unreachable("Cannot emit EK_Inline jump table entry");
1364 case MachineJumpTableInfo::EK_Custom32:
1365 Value = MF->getSubtarget().getTargetLowering()->LowerCustomJumpTableEntry(
1366 MJTI, MBB, UID, OutContext);
1368 case MachineJumpTableInfo::EK_BlockAddress:
1369 // EK_BlockAddress - Each entry is a plain address of block, e.g.:
1371 Value = MCSymbolRefExpr::Create(MBB->getSymbol(), OutContext);
1373 case MachineJumpTableInfo::EK_GPRel32BlockAddress: {
1374 // EK_GPRel32BlockAddress - Each entry is an address of block, encoded
1375 // with a relocation as gp-relative, e.g.:
1377 MCSymbol *MBBSym = MBB->getSymbol();
1378 OutStreamer->EmitGPRel32Value(MCSymbolRefExpr::Create(MBBSym, OutContext));
1382 case MachineJumpTableInfo::EK_GPRel64BlockAddress: {
1383 // EK_GPRel64BlockAddress - Each entry is an address of block, encoded
1384 // with a relocation as gp-relative, e.g.:
1386 MCSymbol *MBBSym = MBB->getSymbol();
1387 OutStreamer->EmitGPRel64Value(MCSymbolRefExpr::Create(MBBSym, OutContext));
1391 case MachineJumpTableInfo::EK_LabelDifference32: {
1392 // Each entry is the address of the block minus the address of the jump
1393 // table. This is used for PIC jump tables where gprel32 is not supported.
1395 // .word LBB123 - LJTI1_2
1396 // If the .set directive avoids relocations, this is emitted as:
1397 // .set L4_5_set_123, LBB123 - LJTI1_2
1398 // .word L4_5_set_123
1399 if (MAI->doesSetDirectiveSuppressesReloc()) {
1400 Value = MCSymbolRefExpr::Create(GetJTSetSymbol(UID, MBB->getNumber()),
1404 Value = MCSymbolRefExpr::Create(MBB->getSymbol(), OutContext);
1405 const TargetLowering *TLI = MF->getSubtarget().getTargetLowering();
1406 const MCExpr *Base = TLI->getPICJumpTableRelocBaseExpr(MF, UID, OutContext);
1407 Value = MCBinaryExpr::CreateSub(Value, Base, OutContext);
1412 assert(Value && "Unknown entry kind!");
1414 unsigned EntrySize =
1415 MJTI->getEntrySize(*TM.getDataLayout());
1416 OutStreamer->EmitValue(Value, EntrySize);
1420 /// EmitSpecialLLVMGlobal - Check to see if the specified global is a
1421 /// special global used by LLVM. If so, emit it and return true, otherwise
1422 /// do nothing and return false.
1423 bool AsmPrinter::EmitSpecialLLVMGlobal(const GlobalVariable *GV) {
1424 if (GV->getName() == "llvm.used") {
1425 if (MAI->hasNoDeadStrip()) // No need to emit this at all.
1426 EmitLLVMUsedList(cast<ConstantArray>(GV->getInitializer()));
1430 // Ignore debug and non-emitted data. This handles llvm.compiler.used.
1431 if (StringRef(GV->getSection()) == "llvm.metadata" ||
1432 GV->hasAvailableExternallyLinkage())
1435 if (!GV->hasAppendingLinkage()) return false;
1437 assert(GV->hasInitializer() && "Not a special LLVM global!");
1439 if (GV->getName() == "llvm.global_ctors") {
1440 EmitXXStructorList(GV->getInitializer(), /* isCtor */ true);
1442 if (TM.getRelocationModel() == Reloc::Static &&
1443 MAI->hasStaticCtorDtorReferenceInStaticMode()) {
1444 StringRef Sym(".constructors_used");
1445 OutStreamer->EmitSymbolAttribute(OutContext.getOrCreateSymbol(Sym),
1451 if (GV->getName() == "llvm.global_dtors") {
1452 EmitXXStructorList(GV->getInitializer(), /* isCtor */ false);
1454 if (TM.getRelocationModel() == Reloc::Static &&
1455 MAI->hasStaticCtorDtorReferenceInStaticMode()) {
1456 StringRef Sym(".destructors_used");
1457 OutStreamer->EmitSymbolAttribute(OutContext.getOrCreateSymbol(Sym),
1466 /// EmitLLVMUsedList - For targets that define a MAI::UsedDirective, mark each
1467 /// global in the specified llvm.used list for which emitUsedDirectiveFor
1468 /// is true, as being used with this directive.
1469 void AsmPrinter::EmitLLVMUsedList(const ConstantArray *InitList) {
1470 // Should be an array of 'i8*'.
1471 for (unsigned i = 0, e = InitList->getNumOperands(); i != e; ++i) {
1472 const GlobalValue *GV =
1473 dyn_cast<GlobalValue>(InitList->getOperand(i)->stripPointerCasts());
1475 OutStreamer->EmitSymbolAttribute(getSymbol(GV), MCSA_NoDeadStrip);
1481 Structor() : Priority(0), Func(nullptr), ComdatKey(nullptr) {}
1483 llvm::Constant *Func;
1484 llvm::GlobalValue *ComdatKey;
1488 /// EmitXXStructorList - Emit the ctor or dtor list taking into account the init
1490 void AsmPrinter::EmitXXStructorList(const Constant *List, bool isCtor) {
1491 // Should be an array of '{ int, void ()* }' structs. The first value is the
1493 if (!isa<ConstantArray>(List)) return;
1495 // Sanity check the structors list.
1496 const ConstantArray *InitList = dyn_cast<ConstantArray>(List);
1497 if (!InitList) return; // Not an array!
1498 StructType *ETy = dyn_cast<StructType>(InitList->getType()->getElementType());
1499 // FIXME: Only allow the 3-field form in LLVM 4.0.
1500 if (!ETy || ETy->getNumElements() < 2 || ETy->getNumElements() > 3)
1501 return; // Not an array of two or three elements!
1502 if (!isa<IntegerType>(ETy->getTypeAtIndex(0U)) ||
1503 !isa<PointerType>(ETy->getTypeAtIndex(1U))) return; // Not (int, ptr).
1504 if (ETy->getNumElements() == 3 && !isa<PointerType>(ETy->getTypeAtIndex(2U)))
1505 return; // Not (int, ptr, ptr).
1507 // Gather the structors in a form that's convenient for sorting by priority.
1508 SmallVector<Structor, 8> Structors;
1509 for (Value *O : InitList->operands()) {
1510 ConstantStruct *CS = dyn_cast<ConstantStruct>(O);
1511 if (!CS) continue; // Malformed.
1512 if (CS->getOperand(1)->isNullValue())
1513 break; // Found a null terminator, skip the rest.
1514 ConstantInt *Priority = dyn_cast<ConstantInt>(CS->getOperand(0));
1515 if (!Priority) continue; // Malformed.
1516 Structors.push_back(Structor());
1517 Structor &S = Structors.back();
1518 S.Priority = Priority->getLimitedValue(65535);
1519 S.Func = CS->getOperand(1);
1520 if (ETy->getNumElements() == 3 && !CS->getOperand(2)->isNullValue())
1521 S.ComdatKey = dyn_cast<GlobalValue>(CS->getOperand(2)->stripPointerCasts());
1524 // Emit the function pointers in the target-specific order
1525 const DataLayout *DL = TM.getDataLayout();
1526 unsigned Align = Log2_32(DL->getPointerPrefAlignment());
1527 std::stable_sort(Structors.begin(), Structors.end(),
1528 [](const Structor &L,
1529 const Structor &R) { return L.Priority < R.Priority; });
1530 for (Structor &S : Structors) {
1531 const TargetLoweringObjectFile &Obj = getObjFileLowering();
1532 const MCSymbol *KeySym = nullptr;
1533 if (GlobalValue *GV = S.ComdatKey) {
1534 if (GV->hasAvailableExternallyLinkage())
1535 // If the associated variable is available_externally, some other TU
1536 // will provide its dynamic initializer.
1539 KeySym = getSymbol(GV);
1541 MCSection *OutputSection =
1542 (isCtor ? Obj.getStaticCtorSection(S.Priority, KeySym)
1543 : Obj.getStaticDtorSection(S.Priority, KeySym));
1544 OutStreamer->SwitchSection(OutputSection);
1545 if (OutStreamer->getCurrentSection() != OutStreamer->getPreviousSection())
1546 EmitAlignment(Align);
1547 EmitXXStructor(S.Func);
1551 void AsmPrinter::EmitModuleIdents(Module &M) {
1552 if (!MAI->hasIdentDirective())
1555 if (const NamedMDNode *NMD = M.getNamedMetadata("llvm.ident")) {
1556 for (unsigned i = 0, e = NMD->getNumOperands(); i != e; ++i) {
1557 const MDNode *N = NMD->getOperand(i);
1558 assert(N->getNumOperands() == 1 &&
1559 "llvm.ident metadata entry can have only one operand");
1560 const MDString *S = cast<MDString>(N->getOperand(0));
1561 OutStreamer->EmitIdent(S->getString());
1566 //===--------------------------------------------------------------------===//
1567 // Emission and print routines
1570 /// EmitInt8 - Emit a byte directive and value.
1572 void AsmPrinter::EmitInt8(int Value) const {
1573 OutStreamer->EmitIntValue(Value, 1);
1576 /// EmitInt16 - Emit a short directive and value.
1578 void AsmPrinter::EmitInt16(int Value) const {
1579 OutStreamer->EmitIntValue(Value, 2);
1582 /// EmitInt32 - Emit a long directive and value.
1584 void AsmPrinter::EmitInt32(int Value) const {
1585 OutStreamer->EmitIntValue(Value, 4);
1588 /// Emit something like ".long Hi-Lo" where the size in bytes of the directive
1589 /// is specified by Size and Hi/Lo specify the labels. This implicitly uses
1590 /// .set if it avoids relocations.
1591 void AsmPrinter::EmitLabelDifference(const MCSymbol *Hi, const MCSymbol *Lo,
1592 unsigned Size) const {
1593 if (!MAI->doesDwarfUseRelocationsAcrossSections())
1594 if (OutStreamer->emitAbsoluteSymbolDiff(Hi, Lo, Size))
1597 // Get the Hi-Lo expression.
1598 const MCExpr *Diff =
1599 MCBinaryExpr::CreateSub(MCSymbolRefExpr::Create(Hi, OutContext),
1600 MCSymbolRefExpr::Create(Lo, OutContext),
1603 if (!MAI->doesSetDirectiveSuppressesReloc()) {
1604 OutStreamer->EmitValue(Diff, Size);
1608 // Otherwise, emit with .set (aka assignment).
1609 MCSymbol *SetLabel = createTempSymbol("set");
1610 OutStreamer->EmitAssignment(SetLabel, Diff);
1611 OutStreamer->EmitSymbolValue(SetLabel, Size);
1614 /// EmitLabelPlusOffset - Emit something like ".long Label+Offset"
1615 /// where the size in bytes of the directive is specified by Size and Label
1616 /// specifies the label. This implicitly uses .set if it is available.
1617 void AsmPrinter::EmitLabelPlusOffset(const MCSymbol *Label, uint64_t Offset,
1619 bool IsSectionRelative) const {
1620 if (MAI->needsDwarfSectionOffsetDirective() && IsSectionRelative) {
1621 OutStreamer->EmitCOFFSecRel32(Label);
1625 // Emit Label+Offset (or just Label if Offset is zero)
1626 const MCExpr *Expr = MCSymbolRefExpr::Create(Label, OutContext);
1628 Expr = MCBinaryExpr::CreateAdd(
1629 Expr, MCConstantExpr::Create(Offset, OutContext), OutContext);
1631 OutStreamer->EmitValue(Expr, Size);
1634 //===----------------------------------------------------------------------===//
1636 // EmitAlignment - Emit an alignment directive to the specified power of
1637 // two boundary. For example, if you pass in 3 here, you will get an 8
1638 // byte alignment. If a global value is specified, and if that global has
1639 // an explicit alignment requested, it will override the alignment request
1640 // if required for correctness.
1642 void AsmPrinter::EmitAlignment(unsigned NumBits, const GlobalObject *GV) const {
1644 NumBits = getGVAlignmentLog2(GV, *TM.getDataLayout(),
1647 if (NumBits == 0) return; // 1-byte aligned: no need to emit alignment.
1650 static_cast<unsigned>(std::numeric_limits<unsigned>::digits) &&
1651 "undefined behavior");
1652 if (getCurrentSection()->getKind().isText())
1653 OutStreamer->EmitCodeAlignment(1u << NumBits);
1655 OutStreamer->EmitValueToAlignment(1u << NumBits);
1658 //===----------------------------------------------------------------------===//
1659 // Constant emission.
1660 //===----------------------------------------------------------------------===//
1662 const MCExpr *AsmPrinter::lowerConstant(const Constant *CV) {
1663 MCContext &Ctx = OutContext;
1665 if (CV->isNullValue() || isa<UndefValue>(CV))
1666 return MCConstantExpr::Create(0, Ctx);
1668 if (const ConstantInt *CI = dyn_cast<ConstantInt>(CV))
1669 return MCConstantExpr::Create(CI->getZExtValue(), Ctx);
1671 if (const GlobalValue *GV = dyn_cast<GlobalValue>(CV))
1672 return MCSymbolRefExpr::Create(getSymbol(GV), Ctx);
1674 if (const BlockAddress *BA = dyn_cast<BlockAddress>(CV))
1675 return MCSymbolRefExpr::Create(GetBlockAddressSymbol(BA), Ctx);
1677 const ConstantExpr *CE = dyn_cast<ConstantExpr>(CV);
1679 llvm_unreachable("Unknown constant value to lower!");
1682 if (const MCExpr *RelocExpr
1683 = getObjFileLowering().getExecutableRelativeSymbol(CE, *Mang, TM))
1686 switch (CE->getOpcode()) {
1688 // If the code isn't optimized, there may be outstanding folding
1689 // opportunities. Attempt to fold the expression using DataLayout as a
1690 // last resort before giving up.
1691 if (Constant *C = ConstantFoldConstantExpression(CE, *TM.getDataLayout()))
1693 return lowerConstant(C);
1695 // Otherwise report the problem to the user.
1698 raw_string_ostream OS(S);
1699 OS << "Unsupported expression in static initializer: ";
1700 CE->printAsOperand(OS, /*PrintType=*/false,
1701 !MF ? nullptr : MF->getFunction()->getParent());
1702 report_fatal_error(OS.str());
1704 case Instruction::GetElementPtr: {
1705 const DataLayout &DL = *TM.getDataLayout();
1707 // Generate a symbolic expression for the byte address
1708 APInt OffsetAI(DL.getPointerTypeSizeInBits(CE->getType()), 0);
1709 cast<GEPOperator>(CE)->accumulateConstantOffset(DL, OffsetAI);
1711 const MCExpr *Base = lowerConstant(CE->getOperand(0));
1715 int64_t Offset = OffsetAI.getSExtValue();
1716 return MCBinaryExpr::CreateAdd(Base, MCConstantExpr::Create(Offset, Ctx),
1720 case Instruction::Trunc:
1721 // We emit the value and depend on the assembler to truncate the generated
1722 // expression properly. This is important for differences between
1723 // blockaddress labels. Since the two labels are in the same function, it
1724 // is reasonable to treat their delta as a 32-bit value.
1726 case Instruction::BitCast:
1727 return lowerConstant(CE->getOperand(0));
1729 case Instruction::IntToPtr: {
1730 const DataLayout &DL = *TM.getDataLayout();
1732 // Handle casts to pointers by changing them into casts to the appropriate
1733 // integer type. This promotes constant folding and simplifies this code.
1734 Constant *Op = CE->getOperand(0);
1735 Op = ConstantExpr::getIntegerCast(Op, DL.getIntPtrType(CV->getType()),
1737 return lowerConstant(Op);
1740 case Instruction::PtrToInt: {
1741 const DataLayout &DL = *TM.getDataLayout();
1743 // Support only foldable casts to/from pointers that can be eliminated by
1744 // changing the pointer to the appropriately sized integer type.
1745 Constant *Op = CE->getOperand(0);
1746 Type *Ty = CE->getType();
1748 const MCExpr *OpExpr = lowerConstant(Op);
1750 // We can emit the pointer value into this slot if the slot is an
1751 // integer slot equal to the size of the pointer.
1752 if (DL.getTypeAllocSize(Ty) == DL.getTypeAllocSize(Op->getType()))
1755 // Otherwise the pointer is smaller than the resultant integer, mask off
1756 // the high bits so we are sure to get a proper truncation if the input is
1758 unsigned InBits = DL.getTypeAllocSizeInBits(Op->getType());
1759 const MCExpr *MaskExpr = MCConstantExpr::Create(~0ULL >> (64-InBits), Ctx);
1760 return MCBinaryExpr::CreateAnd(OpExpr, MaskExpr, Ctx);
1763 // The MC library also has a right-shift operator, but it isn't consistently
1764 // signed or unsigned between different targets.
1765 case Instruction::Add:
1766 case Instruction::Sub:
1767 case Instruction::Mul:
1768 case Instruction::SDiv:
1769 case Instruction::SRem:
1770 case Instruction::Shl:
1771 case Instruction::And:
1772 case Instruction::Or:
1773 case Instruction::Xor: {
1774 const MCExpr *LHS = lowerConstant(CE->getOperand(0));
1775 const MCExpr *RHS = lowerConstant(CE->getOperand(1));
1776 switch (CE->getOpcode()) {
1777 default: llvm_unreachable("Unknown binary operator constant cast expr");
1778 case Instruction::Add: return MCBinaryExpr::CreateAdd(LHS, RHS, Ctx);
1779 case Instruction::Sub: return MCBinaryExpr::CreateSub(LHS, RHS, Ctx);
1780 case Instruction::Mul: return MCBinaryExpr::CreateMul(LHS, RHS, Ctx);
1781 case Instruction::SDiv: return MCBinaryExpr::CreateDiv(LHS, RHS, Ctx);
1782 case Instruction::SRem: return MCBinaryExpr::CreateMod(LHS, RHS, Ctx);
1783 case Instruction::Shl: return MCBinaryExpr::CreateShl(LHS, RHS, Ctx);
1784 case Instruction::And: return MCBinaryExpr::CreateAnd(LHS, RHS, Ctx);
1785 case Instruction::Or: return MCBinaryExpr::CreateOr (LHS, RHS, Ctx);
1786 case Instruction::Xor: return MCBinaryExpr::CreateXor(LHS, RHS, Ctx);
1792 static void emitGlobalConstantImpl(const Constant *C, AsmPrinter &AP,
1793 const Constant *BaseCV = nullptr,
1794 uint64_t Offset = 0);
1796 /// isRepeatedByteSequence - Determine whether the given value is
1797 /// composed of a repeated sequence of identical bytes and return the
1798 /// byte value. If it is not a repeated sequence, return -1.
1799 static int isRepeatedByteSequence(const ConstantDataSequential *V) {
1800 StringRef Data = V->getRawDataValues();
1801 assert(!Data.empty() && "Empty aggregates should be CAZ node");
1803 for (unsigned i = 1, e = Data.size(); i != e; ++i)
1804 if (Data[i] != C) return -1;
1805 return static_cast<uint8_t>(C); // Ensure 255 is not returned as -1.
1809 /// isRepeatedByteSequence - Determine whether the given value is
1810 /// composed of a repeated sequence of identical bytes and return the
1811 /// byte value. If it is not a repeated sequence, return -1.
1812 static int isRepeatedByteSequence(const Value *V, TargetMachine &TM) {
1814 if (const ConstantInt *CI = dyn_cast<ConstantInt>(V)) {
1815 if (CI->getBitWidth() > 64) return -1;
1818 TM.getDataLayout()->getTypeAllocSize(V->getType());
1819 uint64_t Value = CI->getZExtValue();
1821 // Make sure the constant is at least 8 bits long and has a power
1822 // of 2 bit width. This guarantees the constant bit width is
1823 // always a multiple of 8 bits, avoiding issues with padding out
1824 // to Size and other such corner cases.
1825 if (CI->getBitWidth() < 8 || !isPowerOf2_64(CI->getBitWidth())) return -1;
1827 uint8_t Byte = static_cast<uint8_t>(Value);
1829 for (unsigned i = 1; i < Size; ++i) {
1831 if (static_cast<uint8_t>(Value) != Byte) return -1;
1835 if (const ConstantArray *CA = dyn_cast<ConstantArray>(V)) {
1836 // Make sure all array elements are sequences of the same repeated
1838 assert(CA->getNumOperands() != 0 && "Should be a CAZ");
1839 int Byte = isRepeatedByteSequence(CA->getOperand(0), TM);
1840 if (Byte == -1) return -1;
1842 for (unsigned i = 1, e = CA->getNumOperands(); i != e; ++i) {
1843 int ThisByte = isRepeatedByteSequence(CA->getOperand(i), TM);
1844 if (ThisByte == -1) return -1;
1845 if (Byte != ThisByte) return -1;
1850 if (const ConstantDataSequential *CDS = dyn_cast<ConstantDataSequential>(V))
1851 return isRepeatedByteSequence(CDS);
1856 static void emitGlobalConstantDataSequential(const ConstantDataSequential *CDS,
1859 // See if we can aggregate this into a .fill, if so, emit it as such.
1860 int Value = isRepeatedByteSequence(CDS, AP.TM);
1863 AP.TM.getDataLayout()->getTypeAllocSize(
1865 // Don't emit a 1-byte object as a .fill.
1867 return AP.OutStreamer->EmitFill(Bytes, Value);
1870 // If this can be emitted with .ascii/.asciz, emit it as such.
1871 if (CDS->isString())
1872 return AP.OutStreamer->EmitBytes(CDS->getAsString());
1874 // Otherwise, emit the values in successive locations.
1875 unsigned ElementByteSize = CDS->getElementByteSize();
1876 if (isa<IntegerType>(CDS->getElementType())) {
1877 for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i) {
1879 AP.OutStreamer->GetCommentOS() << format("0x%" PRIx64 "\n",
1880 CDS->getElementAsInteger(i));
1881 AP.OutStreamer->EmitIntValue(CDS->getElementAsInteger(i),
1884 } else if (ElementByteSize == 4) {
1885 // FP Constants are printed as integer constants to avoid losing
1887 assert(CDS->getElementType()->isFloatTy());
1888 for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i) {
1894 F = CDS->getElementAsFloat(i);
1896 AP.OutStreamer->GetCommentOS() << "float " << F << '\n';
1897 AP.OutStreamer->EmitIntValue(I, 4);
1900 assert(CDS->getElementType()->isDoubleTy());
1901 for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i) {
1907 F = CDS->getElementAsDouble(i);
1909 AP.OutStreamer->GetCommentOS() << "double " << F << '\n';
1910 AP.OutStreamer->EmitIntValue(I, 8);
1914 const DataLayout &DL = *AP.TM.getDataLayout();
1915 unsigned Size = DL.getTypeAllocSize(CDS->getType());
1916 unsigned EmittedSize = DL.getTypeAllocSize(CDS->getType()->getElementType()) *
1917 CDS->getNumElements();
1918 if (unsigned Padding = Size - EmittedSize)
1919 AP.OutStreamer->EmitZeros(Padding);
1923 static void emitGlobalConstantArray(const ConstantArray *CA, AsmPrinter &AP,
1924 const Constant *BaseCV, uint64_t Offset) {
1925 // See if we can aggregate some values. Make sure it can be
1926 // represented as a series of bytes of the constant value.
1927 int Value = isRepeatedByteSequence(CA, AP.TM);
1928 const DataLayout &DL = *AP.TM.getDataLayout();
1931 uint64_t Bytes = DL.getTypeAllocSize(CA->getType());
1932 AP.OutStreamer->EmitFill(Bytes, Value);
1935 for (unsigned i = 0, e = CA->getNumOperands(); i != e; ++i) {
1936 emitGlobalConstantImpl(CA->getOperand(i), AP, BaseCV, Offset);
1937 Offset += DL.getTypeAllocSize(CA->getOperand(i)->getType());
1942 static void emitGlobalConstantVector(const ConstantVector *CV, AsmPrinter &AP) {
1943 for (unsigned i = 0, e = CV->getType()->getNumElements(); i != e; ++i)
1944 emitGlobalConstantImpl(CV->getOperand(i), AP);
1946 const DataLayout &DL = *AP.TM.getDataLayout();
1947 unsigned Size = DL.getTypeAllocSize(CV->getType());
1948 unsigned EmittedSize = DL.getTypeAllocSize(CV->getType()->getElementType()) *
1949 CV->getType()->getNumElements();
1950 if (unsigned Padding = Size - EmittedSize)
1951 AP.OutStreamer->EmitZeros(Padding);
1954 static void emitGlobalConstantStruct(const ConstantStruct *CS, AsmPrinter &AP,
1955 const Constant *BaseCV, uint64_t Offset) {
1956 // Print the fields in successive locations. Pad to align if needed!
1957 const DataLayout *DL = AP.TM.getDataLayout();
1958 unsigned Size = DL->getTypeAllocSize(CS->getType());
1959 const StructLayout *Layout = DL->getStructLayout(CS->getType());
1960 uint64_t SizeSoFar = 0;
1961 for (unsigned i = 0, e = CS->getNumOperands(); i != e; ++i) {
1962 const Constant *Field = CS->getOperand(i);
1964 // Print the actual field value.
1965 emitGlobalConstantImpl(Field, AP, BaseCV, Offset+SizeSoFar);
1967 // Check if padding is needed and insert one or more 0s.
1968 uint64_t FieldSize = DL->getTypeAllocSize(Field->getType());
1969 uint64_t PadSize = ((i == e-1 ? Size : Layout->getElementOffset(i+1))
1970 - Layout->getElementOffset(i)) - FieldSize;
1971 SizeSoFar += FieldSize + PadSize;
1973 // Insert padding - this may include padding to increase the size of the
1974 // current field up to the ABI size (if the struct is not packed) as well
1975 // as padding to ensure that the next field starts at the right offset.
1976 AP.OutStreamer->EmitZeros(PadSize);
1978 assert(SizeSoFar == Layout->getSizeInBytes() &&
1979 "Layout of constant struct may be incorrect!");
1982 static void emitGlobalConstantFP(const ConstantFP *CFP, AsmPrinter &AP) {
1983 APInt API = CFP->getValueAPF().bitcastToAPInt();
1985 // First print a comment with what we think the original floating-point value
1986 // should have been.
1987 if (AP.isVerbose()) {
1988 SmallString<8> StrVal;
1989 CFP->getValueAPF().toString(StrVal);
1992 CFP->getType()->print(AP.OutStreamer->GetCommentOS());
1994 AP.OutStreamer->GetCommentOS() << "Printing <null> Type";
1995 AP.OutStreamer->GetCommentOS() << ' ' << StrVal << '\n';
1998 // Now iterate through the APInt chunks, emitting them in endian-correct
1999 // order, possibly with a smaller chunk at beginning/end (e.g. for x87 80-bit
2001 unsigned NumBytes = API.getBitWidth() / 8;
2002 unsigned TrailingBytes = NumBytes % sizeof(uint64_t);
2003 const uint64_t *p = API.getRawData();
2005 // PPC's long double has odd notions of endianness compared to how LLVM
2006 // handles it: p[0] goes first for *big* endian on PPC.
2007 if (AP.TM.getDataLayout()->isBigEndian() &&
2008 !CFP->getType()->isPPC_FP128Ty()) {
2009 int Chunk = API.getNumWords() - 1;
2012 AP.OutStreamer->EmitIntValue(p[Chunk--], TrailingBytes);
2014 for (; Chunk >= 0; --Chunk)
2015 AP.OutStreamer->EmitIntValue(p[Chunk], sizeof(uint64_t));
2018 for (Chunk = 0; Chunk < NumBytes / sizeof(uint64_t); ++Chunk)
2019 AP.OutStreamer->EmitIntValue(p[Chunk], sizeof(uint64_t));
2022 AP.OutStreamer->EmitIntValue(p[Chunk], TrailingBytes);
2025 // Emit the tail padding for the long double.
2026 const DataLayout &DL = *AP.TM.getDataLayout();
2027 AP.OutStreamer->EmitZeros(DL.getTypeAllocSize(CFP->getType()) -
2028 DL.getTypeStoreSize(CFP->getType()));
2031 static void emitGlobalConstantLargeInt(const ConstantInt *CI, AsmPrinter &AP) {
2032 const DataLayout *DL = AP.TM.getDataLayout();
2033 unsigned BitWidth = CI->getBitWidth();
2035 // Copy the value as we may massage the layout for constants whose bit width
2036 // is not a multiple of 64-bits.
2037 APInt Realigned(CI->getValue());
2038 uint64_t ExtraBits = 0;
2039 unsigned ExtraBitsSize = BitWidth & 63;
2041 if (ExtraBitsSize) {
2042 // The bit width of the data is not a multiple of 64-bits.
2043 // The extra bits are expected to be at the end of the chunk of the memory.
2045 // * Nothing to be done, just record the extra bits to emit.
2047 // * Record the extra bits to emit.
2048 // * Realign the raw data to emit the chunks of 64-bits.
2049 if (DL->isBigEndian()) {
2050 // Basically the structure of the raw data is a chunk of 64-bits cells:
2051 // 0 1 BitWidth / 64
2052 // [chunk1][chunk2] ... [chunkN].
2053 // The most significant chunk is chunkN and it should be emitted first.
2054 // However, due to the alignment issue chunkN contains useless bits.
2055 // Realign the chunks so that they contain only useless information:
2056 // ExtraBits 0 1 (BitWidth / 64) - 1
2057 // chu[nk1 chu][nk2 chu] ... [nkN-1 chunkN]
2058 ExtraBits = Realigned.getRawData()[0] &
2059 (((uint64_t)-1) >> (64 - ExtraBitsSize));
2060 Realigned = Realigned.lshr(ExtraBitsSize);
2062 ExtraBits = Realigned.getRawData()[BitWidth / 64];
2065 // We don't expect assemblers to support integer data directives
2066 // for more than 64 bits, so we emit the data in at most 64-bit
2067 // quantities at a time.
2068 const uint64_t *RawData = Realigned.getRawData();
2069 for (unsigned i = 0, e = BitWidth / 64; i != e; ++i) {
2070 uint64_t Val = DL->isBigEndian() ? RawData[e - i - 1] : RawData[i];
2071 AP.OutStreamer->EmitIntValue(Val, 8);
2074 if (ExtraBitsSize) {
2075 // Emit the extra bits after the 64-bits chunks.
2077 // Emit a directive that fills the expected size.
2078 uint64_t Size = AP.TM.getDataLayout()->getTypeAllocSize(
2080 Size -= (BitWidth / 64) * 8;
2081 assert(Size && Size * 8 >= ExtraBitsSize &&
2082 (ExtraBits & (((uint64_t)-1) >> (64 - ExtraBitsSize)))
2083 == ExtraBits && "Directive too small for extra bits.");
2084 AP.OutStreamer->EmitIntValue(ExtraBits, Size);
2088 /// \brief Transform a not absolute MCExpr containing a reference to a GOT
2089 /// equivalent global, by a target specific GOT pc relative access to the
2091 static void handleIndirectSymViaGOTPCRel(AsmPrinter &AP, const MCExpr **ME,
2092 const Constant *BaseCst,
2094 // The global @foo below illustrates a global that uses a got equivalent.
2096 // @bar = global i32 42
2097 // @gotequiv = private unnamed_addr constant i32* @bar
2098 // @foo = i32 trunc (i64 sub (i64 ptrtoint (i32** @gotequiv to i64),
2099 // i64 ptrtoint (i32* @foo to i64))
2102 // The cstexpr in @foo is converted into the MCExpr `ME`, where we actually
2103 // check whether @foo is suitable to use a GOTPCREL. `ME` is usually in the
2106 // foo = cstexpr, where
2107 // cstexpr := <gotequiv> - "." + <cst>
2108 // cstexpr := <gotequiv> - (<foo> - <offset from @foo base>) + <cst>
2110 // After canonicalization by EvaluateAsRelocatable `ME` turns into:
2112 // cstexpr := <gotequiv> - <foo> + gotpcrelcst, where
2113 // gotpcrelcst := <offset from @foo base> + <cst>
2116 if (!(*ME)->EvaluateAsRelocatable(MV, nullptr, nullptr) || MV.isAbsolute())
2119 const MCSymbol *GOTEquivSym = &MV.getSymA()->getSymbol();
2120 if (!AP.GlobalGOTEquivs.count(GOTEquivSym))
2123 const GlobalValue *BaseGV = dyn_cast<GlobalValue>(BaseCst);
2127 const MCSymbol *BaseSym = AP.getSymbol(BaseGV);
2128 if (BaseSym != &MV.getSymB()->getSymbol())
2131 // Make sure to match:
2133 // gotpcrelcst := <offset from @foo base> + <cst>
2135 // If gotpcrelcst is positive it means that we can safely fold the pc rel
2136 // displacement into the GOTPCREL. We can also can have an extra offset <cst>
2137 // if the target knows how to encode it.
2139 int64_t GOTPCRelCst = Offset + MV.getConstant();
2140 if (GOTPCRelCst < 0)
2142 if (!AP.getObjFileLowering().supportGOTPCRelWithOffset() && GOTPCRelCst != 0)
2145 // Emit the GOT PC relative to replace the got equivalent global, i.e.:
2152 // .long gotequiv - "." + <cst>
2154 // is replaced by the target specific equivalent to:
2159 // .long bar@GOTPCREL+<gotpcrelcst>
2161 AsmPrinter::GOTEquivUsePair Result = AP.GlobalGOTEquivs[GOTEquivSym];
2162 const GlobalVariable *GV = Result.first;
2163 int NumUses = (int)Result.second;
2164 const GlobalValue *FinalGV = dyn_cast<GlobalValue>(GV->getOperand(0));
2165 const MCSymbol *FinalSym = AP.getSymbol(FinalGV);
2166 *ME = AP.getObjFileLowering().getIndirectSymViaGOTPCRel(
2167 FinalSym, MV, Offset, AP.MMI, *AP.OutStreamer);
2169 // Update GOT equivalent usage information
2172 AP.GlobalGOTEquivs[GOTEquivSym] = std::make_pair(GV, NumUses);
2175 static void emitGlobalConstantImpl(const Constant *CV, AsmPrinter &AP,
2176 const Constant *BaseCV, uint64_t Offset) {
2177 const DataLayout *DL = AP.TM.getDataLayout();
2178 uint64_t Size = DL->getTypeAllocSize(CV->getType());
2180 // Globals with sub-elements such as combinations of arrays and structs
2181 // are handled recursively by emitGlobalConstantImpl. Keep track of the
2182 // constant symbol base and the current position with BaseCV and Offset.
2183 if (!BaseCV && CV->hasOneUse())
2184 BaseCV = dyn_cast<Constant>(CV->user_back());
2186 if (isa<ConstantAggregateZero>(CV) || isa<UndefValue>(CV))
2187 return AP.OutStreamer->EmitZeros(Size);
2189 if (const ConstantInt *CI = dyn_cast<ConstantInt>(CV)) {
2196 AP.OutStreamer->GetCommentOS() << format("0x%" PRIx64 "\n",
2197 CI->getZExtValue());
2198 AP.OutStreamer->EmitIntValue(CI->getZExtValue(), Size);
2201 emitGlobalConstantLargeInt(CI, AP);
2206 if (const ConstantFP *CFP = dyn_cast<ConstantFP>(CV))
2207 return emitGlobalConstantFP(CFP, AP);
2209 if (isa<ConstantPointerNull>(CV)) {
2210 AP.OutStreamer->EmitIntValue(0, Size);
2214 if (const ConstantDataSequential *CDS = dyn_cast<ConstantDataSequential>(CV))
2215 return emitGlobalConstantDataSequential(CDS, AP);
2217 if (const ConstantArray *CVA = dyn_cast<ConstantArray>(CV))
2218 return emitGlobalConstantArray(CVA, AP, BaseCV, Offset);
2220 if (const ConstantStruct *CVS = dyn_cast<ConstantStruct>(CV))
2221 return emitGlobalConstantStruct(CVS, AP, BaseCV, Offset);
2223 if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(CV)) {
2224 // Look through bitcasts, which might not be able to be MCExpr'ized (e.g. of
2226 if (CE->getOpcode() == Instruction::BitCast)
2227 return emitGlobalConstantImpl(CE->getOperand(0), AP);
2230 // If the constant expression's size is greater than 64-bits, then we have
2231 // to emit the value in chunks. Try to constant fold the value and emit it
2233 Constant *New = ConstantFoldConstantExpression(CE, *DL);
2234 if (New && New != CE)
2235 return emitGlobalConstantImpl(New, AP);
2239 if (const ConstantVector *V = dyn_cast<ConstantVector>(CV))
2240 return emitGlobalConstantVector(V, AP);
2242 // Otherwise, it must be a ConstantExpr. Lower it to an MCExpr, then emit it
2243 // thread the streamer with EmitValue.
2244 const MCExpr *ME = AP.lowerConstant(CV);
2246 // Since lowerConstant already folded and got rid of all IR pointer and
2247 // integer casts, detect GOT equivalent accesses by looking into the MCExpr
2249 if (AP.getObjFileLowering().supportIndirectSymViaGOTPCRel())
2250 handleIndirectSymViaGOTPCRel(AP, &ME, BaseCV, Offset);
2252 AP.OutStreamer->EmitValue(ME, Size);
2255 /// EmitGlobalConstant - Print a general LLVM constant to the .s file.
2256 void AsmPrinter::EmitGlobalConstant(const Constant *CV) {
2258 TM.getDataLayout()->getTypeAllocSize(CV->getType());
2260 emitGlobalConstantImpl(CV, *this);
2261 else if (MAI->hasSubsectionsViaSymbols()) {
2262 // If the global has zero size, emit a single byte so that two labels don't
2263 // look like they are at the same location.
2264 OutStreamer->EmitIntValue(0, 1);
2268 void AsmPrinter::EmitMachineConstantPoolValue(MachineConstantPoolValue *MCPV) {
2269 // Target doesn't support this yet!
2270 llvm_unreachable("Target does not support EmitMachineConstantPoolValue");
2273 void AsmPrinter::printOffset(int64_t Offset, raw_ostream &OS) const {
2275 OS << '+' << Offset;
2276 else if (Offset < 0)
2280 //===----------------------------------------------------------------------===//
2281 // Symbol Lowering Routines.
2282 //===----------------------------------------------------------------------===//
2284 MCSymbol *AsmPrinter::createTempSymbol(const Twine &Name) const {
2285 return OutContext.createTempSymbol(Name, true);
2288 MCSymbol *AsmPrinter::GetBlockAddressSymbol(const BlockAddress *BA) const {
2289 return MMI->getAddrLabelSymbol(BA->getBasicBlock());
2292 MCSymbol *AsmPrinter::GetBlockAddressSymbol(const BasicBlock *BB) const {
2293 return MMI->getAddrLabelSymbol(BB);
2296 /// GetCPISymbol - Return the symbol for the specified constant pool entry.
2297 MCSymbol *AsmPrinter::GetCPISymbol(unsigned CPID) const {
2298 const DataLayout *DL = TM.getDataLayout();
2299 return OutContext.getOrCreateSymbol
2300 (Twine(DL->getPrivateGlobalPrefix()) + "CPI" + Twine(getFunctionNumber())
2301 + "_" + Twine(CPID));
2304 /// GetJTISymbol - Return the symbol for the specified jump table entry.
2305 MCSymbol *AsmPrinter::GetJTISymbol(unsigned JTID, bool isLinkerPrivate) const {
2306 return MF->getJTISymbol(JTID, OutContext, isLinkerPrivate);
2309 /// GetJTSetSymbol - Return the symbol for the specified jump table .set
2310 /// FIXME: privatize to AsmPrinter.
2311 MCSymbol *AsmPrinter::GetJTSetSymbol(unsigned UID, unsigned MBBID) const {
2312 const DataLayout *DL = TM.getDataLayout();
2313 return OutContext.getOrCreateSymbol
2314 (Twine(DL->getPrivateGlobalPrefix()) + Twine(getFunctionNumber()) + "_" +
2315 Twine(UID) + "_set_" + Twine(MBBID));
2318 MCSymbol *AsmPrinter::getSymbolWithGlobalValueBase(const GlobalValue *GV,
2319 StringRef Suffix) const {
2320 return getObjFileLowering().getSymbolWithGlobalValueBase(GV, Suffix, *Mang,
2324 /// GetExternalSymbolSymbol - Return the MCSymbol for the specified
2326 MCSymbol *AsmPrinter::GetExternalSymbolSymbol(StringRef Sym) const {
2327 SmallString<60> NameStr;
2328 Mang->getNameWithPrefix(NameStr, Sym);
2329 return OutContext.getOrCreateSymbol(NameStr);
2334 /// PrintParentLoopComment - Print comments about parent loops of this one.
2335 static void PrintParentLoopComment(raw_ostream &OS, const MachineLoop *Loop,
2336 unsigned FunctionNumber) {
2338 PrintParentLoopComment(OS, Loop->getParentLoop(), FunctionNumber);
2339 OS.indent(Loop->getLoopDepth()*2)
2340 << "Parent Loop BB" << FunctionNumber << "_"
2341 << Loop->getHeader()->getNumber()
2342 << " Depth=" << Loop->getLoopDepth() << '\n';
2346 /// PrintChildLoopComment - Print comments about child loops within
2347 /// the loop for this basic block, with nesting.
2348 static void PrintChildLoopComment(raw_ostream &OS, const MachineLoop *Loop,
2349 unsigned FunctionNumber) {
2350 // Add child loop information
2351 for (const MachineLoop *CL : *Loop) {
2352 OS.indent(CL->getLoopDepth()*2)
2353 << "Child Loop BB" << FunctionNumber << "_"
2354 << CL->getHeader()->getNumber() << " Depth " << CL->getLoopDepth()
2356 PrintChildLoopComment(OS, CL, FunctionNumber);
2360 /// emitBasicBlockLoopComments - Pretty-print comments for basic blocks.
2361 static void emitBasicBlockLoopComments(const MachineBasicBlock &MBB,
2362 const MachineLoopInfo *LI,
2363 const AsmPrinter &AP) {
2364 // Add loop depth information
2365 const MachineLoop *Loop = LI->getLoopFor(&MBB);
2368 MachineBasicBlock *Header = Loop->getHeader();
2369 assert(Header && "No header for loop");
2371 // If this block is not a loop header, just print out what is the loop header
2373 if (Header != &MBB) {
2374 AP.OutStreamer->AddComment(" in Loop: Header=BB" +
2375 Twine(AP.getFunctionNumber())+"_" +
2376 Twine(Loop->getHeader()->getNumber())+
2377 " Depth="+Twine(Loop->getLoopDepth()));
2381 // Otherwise, it is a loop header. Print out information about child and
2383 raw_ostream &OS = AP.OutStreamer->GetCommentOS();
2385 PrintParentLoopComment(OS, Loop->getParentLoop(), AP.getFunctionNumber());
2388 OS.indent(Loop->getLoopDepth()*2-2);
2393 OS << "Loop Header: Depth=" + Twine(Loop->getLoopDepth()) << '\n';
2395 PrintChildLoopComment(OS, Loop, AP.getFunctionNumber());
2399 /// EmitBasicBlockStart - This method prints the label for the specified
2400 /// MachineBasicBlock, an alignment (if present) and a comment describing
2401 /// it if appropriate.
2402 void AsmPrinter::EmitBasicBlockStart(const MachineBasicBlock &MBB) const {
2403 // Emit an alignment directive for this block, if needed.
2404 if (unsigned Align = MBB.getAlignment())
2405 EmitAlignment(Align);
2407 // If the block has its address taken, emit any labels that were used to
2408 // reference the block. It is possible that there is more than one label
2409 // here, because multiple LLVM BB's may have been RAUW'd to this block after
2410 // the references were generated.
2411 if (MBB.hasAddressTaken()) {
2412 const BasicBlock *BB = MBB.getBasicBlock();
2414 OutStreamer->AddComment("Block address taken");
2416 std::vector<MCSymbol*> Symbols = MMI->getAddrLabelSymbolToEmit(BB);
2417 for (auto *Sym : Symbols)
2418 OutStreamer->EmitLabel(Sym);
2421 // Print some verbose block comments.
2423 if (const BasicBlock *BB = MBB.getBasicBlock())
2425 OutStreamer->AddComment("%" + BB->getName());
2426 emitBasicBlockLoopComments(MBB, LI, *this);
2429 // Print the main label for the block.
2430 if (MBB.pred_empty() || isBlockOnlyReachableByFallthrough(&MBB)) {
2432 // NOTE: Want this comment at start of line, don't emit with AddComment.
2433 OutStreamer->emitRawComment(" BB#" + Twine(MBB.getNumber()) + ":", false);
2436 OutStreamer->EmitLabel(MBB.getSymbol());
2440 void AsmPrinter::EmitVisibility(MCSymbol *Sym, unsigned Visibility,
2441 bool IsDefinition) const {
2442 MCSymbolAttr Attr = MCSA_Invalid;
2444 switch (Visibility) {
2446 case GlobalValue::HiddenVisibility:
2448 Attr = MAI->getHiddenVisibilityAttr();
2450 Attr = MAI->getHiddenDeclarationVisibilityAttr();
2452 case GlobalValue::ProtectedVisibility:
2453 Attr = MAI->getProtectedVisibilityAttr();
2457 if (Attr != MCSA_Invalid)
2458 OutStreamer->EmitSymbolAttribute(Sym, Attr);
2461 /// isBlockOnlyReachableByFallthough - Return true if the basic block has
2462 /// exactly one predecessor and the control transfer mechanism between
2463 /// the predecessor and this block is a fall-through.
2465 isBlockOnlyReachableByFallthrough(const MachineBasicBlock *MBB) const {
2466 // If this is a landing pad, it isn't a fall through. If it has no preds,
2467 // then nothing falls through to it.
2468 if (MBB->isLandingPad() || MBB->pred_empty())
2471 // If there isn't exactly one predecessor, it can't be a fall through.
2472 if (MBB->pred_size() > 1)
2475 // The predecessor has to be immediately before this block.
2476 MachineBasicBlock *Pred = *MBB->pred_begin();
2477 if (!Pred->isLayoutSuccessor(MBB))
2480 // If the block is completely empty, then it definitely does fall through.
2484 // Check the terminators in the previous blocks
2485 for (const auto &MI : Pred->terminators()) {
2486 // If it is not a simple branch, we are in a table somewhere.
2487 if (!MI.isBranch() || MI.isIndirectBranch())
2490 // If we are the operands of one of the branches, this is not a fall
2491 // through. Note that targets with delay slots will usually bundle
2492 // terminators with the delay slot instruction.
2493 for (ConstMIBundleOperands OP(&MI); OP.isValid(); ++OP) {
2496 if (OP->isMBB() && OP->getMBB() == MBB)
2506 GCMetadataPrinter *AsmPrinter::GetOrCreateGCPrinter(GCStrategy &S) {
2507 if (!S.usesMetadata())
2510 assert(!S.useStatepoints() && "statepoints do not currently support custom"
2511 " stackmap formats, please see the documentation for a description of"
2512 " the default format. If you really need a custom serialized format,"
2513 " please file a bug");
2515 gcp_map_type &GCMap = getGCMap(GCMetadataPrinters);
2516 gcp_map_type::iterator GCPI = GCMap.find(&S);
2517 if (GCPI != GCMap.end())
2518 return GCPI->second.get();
2520 const char *Name = S.getName().c_str();
2522 for (GCMetadataPrinterRegistry::iterator
2523 I = GCMetadataPrinterRegistry::begin(),
2524 E = GCMetadataPrinterRegistry::end(); I != E; ++I)
2525 if (strcmp(Name, I->getName()) == 0) {
2526 std::unique_ptr<GCMetadataPrinter> GMP = I->instantiate();
2528 auto IterBool = GCMap.insert(std::make_pair(&S, std::move(GMP)));
2529 return IterBool.first->second.get();
2532 report_fatal_error("no GCMetadataPrinter registered for GC: " + Twine(Name));
2535 /// Pin vtable to this file.
2536 AsmPrinterHandler::~AsmPrinterHandler() {}
2538 void AsmPrinterHandler::markFunctionEnd() {}