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 "AsmPrinterHandler.h"
15 #include "CodeViewDebug.h"
16 #include "DwarfDebug.h"
17 #include "DwarfException.h"
18 #include "WinException.h"
19 #include "llvm/ADT/APFloat.h"
20 #include "llvm/ADT/APInt.h"
21 #include "llvm/ADT/DenseMap.h"
22 #include "llvm/ADT/SmallPtrSet.h"
23 #include "llvm/ADT/SmallString.h"
24 #include "llvm/ADT/SmallVector.h"
25 #include "llvm/ADT/Statistic.h"
26 #include "llvm/ADT/STLExtras.h"
27 #include "llvm/ADT/StringRef.h"
28 #include "llvm/ADT/Triple.h"
29 #include "llvm/ADT/Twine.h"
30 #include "llvm/Analysis/ConstantFolding.h"
31 #include "llvm/Analysis/ObjectUtils.h"
32 #include "llvm/CodeGen/Analysis.h"
33 #include "llvm/CodeGen/AsmPrinter.h"
34 #include "llvm/CodeGen/GCMetadata.h"
35 #include "llvm/CodeGen/GCMetadataPrinter.h"
36 #include "llvm/CodeGen/GCStrategy.h"
37 #include "llvm/CodeGen/MachineBasicBlock.h"
38 #include "llvm/CodeGen/MachineConstantPool.h"
39 #include "llvm/CodeGen/MachineFrameInfo.h"
40 #include "llvm/CodeGen/MachineFunction.h"
41 #include "llvm/CodeGen/MachineFunctionPass.h"
42 #include "llvm/CodeGen/MachineInstr.h"
43 #include "llvm/CodeGen/MachineInstrBundle.h"
44 #include "llvm/CodeGen/MachineJumpTableInfo.h"
45 #include "llvm/CodeGen/MachineLoopInfo.h"
46 #include "llvm/CodeGen/MachineMemOperand.h"
47 #include "llvm/CodeGen/MachineModuleInfoImpls.h"
48 #include "llvm/CodeGen/MachineOperand.h"
49 #include "llvm/CodeGen/MachineOptimizationRemarkEmitter.h"
50 #include "llvm/IR/BasicBlock.h"
51 #include "llvm/IR/Constant.h"
52 #include "llvm/IR/Constants.h"
53 #include "llvm/IR/DataLayout.h"
54 #include "llvm/IR/DebugInfoMetadata.h"
55 #include "llvm/IR/DerivedTypes.h"
56 #include "llvm/IR/Function.h"
57 #include "llvm/IR/GlobalAlias.h"
58 #include "llvm/IR/GlobalIFunc.h"
59 #include "llvm/IR/GlobalIndirectSymbol.h"
60 #include "llvm/IR/GlobalObject.h"
61 #include "llvm/IR/GlobalValue.h"
62 #include "llvm/IR/GlobalVariable.h"
63 #include "llvm/IR/Mangler.h"
64 #include "llvm/IR/Metadata.h"
65 #include "llvm/IR/Module.h"
66 #include "llvm/IR/Operator.h"
67 #include "llvm/IR/Value.h"
68 #include "llvm/MC/MCAsmInfo.h"
69 #include "llvm/MC/MCContext.h"
70 #include "llvm/MC/MCDirectives.h"
71 #include "llvm/MC/MCExpr.h"
72 #include "llvm/MC/MCInst.h"
73 #include "llvm/MC/MCSection.h"
74 #include "llvm/MC/MCSectionELF.h"
75 #include "llvm/MC/MCSectionMachO.h"
76 #include "llvm/MC/MCStreamer.h"
77 #include "llvm/MC/MCSubtargetInfo.h"
78 #include "llvm/MC/MCSymbol.h"
79 #include "llvm/MC/MCTargetOptions.h"
80 #include "llvm/MC/MCValue.h"
81 #include "llvm/MC/SectionKind.h"
82 #include "llvm/Pass.h"
83 #include "llvm/Support/Casting.h"
84 #include "llvm/Support/Compiler.h"
85 #include "llvm/Support/Dwarf.h"
86 #include "llvm/Support/ELF.h"
87 #include "llvm/Support/ErrorHandling.h"
88 #include "llvm/Support/Format.h"
89 #include "llvm/Support/MathExtras.h"
90 #include "llvm/Support/raw_ostream.h"
91 #include "llvm/Support/TargetRegistry.h"
92 #include "llvm/Support/Timer.h"
93 #include "llvm/Target/TargetFrameLowering.h"
94 #include "llvm/Target/TargetInstrInfo.h"
95 #include "llvm/Target/TargetLowering.h"
96 #include "llvm/Target/TargetLoweringObjectFile.h"
97 #include "llvm/Target/TargetMachine.h"
98 #include "llvm/Target/TargetRegisterInfo.h"
99 #include "llvm/Target/TargetSubtargetInfo.h"
110 using namespace llvm;
112 #define DEBUG_TYPE "asm-printer"
114 static const char *const DWARFGroupName = "dwarf";
115 static const char *const DWARFGroupDescription = "DWARF Emission";
116 static const char *const DbgTimerName = "emit";
117 static const char *const DbgTimerDescription = "Debug Info Emission";
118 static const char *const EHTimerName = "write_exception";
119 static const char *const EHTimerDescription = "DWARF Exception Writer";
120 static const char *const CodeViewLineTablesGroupName = "linetables";
121 static const char *const CodeViewLineTablesGroupDescription =
122 "CodeView Line Tables";
124 STATISTIC(EmittedInsts, "Number of machine instrs printed");
127 PrintSchedule("print-schedule", cl::Hidden, cl::init(false),
128 cl::desc("Print 'sched: [latency:throughput]' in .s output"));
130 char AsmPrinter::ID = 0;
132 typedef DenseMap<GCStrategy*, std::unique_ptr<GCMetadataPrinter>> gcp_map_type;
133 static gcp_map_type &getGCMap(void *&P) {
135 P = new gcp_map_type();
136 return *(gcp_map_type*)P;
139 /// getGVAlignmentLog2 - Return the alignment to use for the specified global
140 /// value in log2 form. This rounds up to the preferred alignment if possible
142 static unsigned getGVAlignmentLog2(const GlobalValue *GV, const DataLayout &DL,
143 unsigned InBits = 0) {
144 unsigned NumBits = 0;
145 if (const GlobalVariable *GVar = dyn_cast<GlobalVariable>(GV))
146 NumBits = DL.getPreferredAlignmentLog(GVar);
148 // If InBits is specified, round it to it.
149 if (InBits > NumBits)
152 // If the GV has a specified alignment, take it into account.
153 if (GV->getAlignment() == 0)
156 unsigned GVAlign = Log2_32(GV->getAlignment());
158 // If the GVAlign is larger than NumBits, or if we are required to obey
159 // NumBits because the GV has an assigned section, obey it.
160 if (GVAlign > NumBits || GV->hasSection())
165 AsmPrinter::AsmPrinter(TargetMachine &tm, std::unique_ptr<MCStreamer> Streamer)
166 : MachineFunctionPass(ID), TM(tm), MAI(tm.getMCAsmInfo()),
167 OutContext(Streamer->getContext()), OutStreamer(std::move(Streamer)) {
168 VerboseAsm = OutStreamer->isVerboseAsm();
171 AsmPrinter::~AsmPrinter() {
172 assert(!DD && Handlers.empty() && "Debug/EH info didn't get finalized");
174 if (GCMetadataPrinters) {
175 gcp_map_type &GCMap = getGCMap(GCMetadataPrinters);
178 GCMetadataPrinters = nullptr;
182 bool AsmPrinter::isPositionIndependent() const {
183 return TM.isPositionIndependent();
186 /// getFunctionNumber - Return a unique ID for the current function.
188 unsigned AsmPrinter::getFunctionNumber() const {
189 return MF->getFunctionNumber();
192 const TargetLoweringObjectFile &AsmPrinter::getObjFileLowering() const {
193 return *TM.getObjFileLowering();
196 const DataLayout &AsmPrinter::getDataLayout() const {
197 return MMI->getModule()->getDataLayout();
200 // Do not use the cached DataLayout because some client use it without a Module
201 // (llvm-dsymutil, llvm-dwarfdump).
202 unsigned AsmPrinter::getPointerSize() const { return TM.getPointerSize(); }
204 const MCSubtargetInfo &AsmPrinter::getSubtargetInfo() const {
205 assert(MF && "getSubtargetInfo requires a valid MachineFunction!");
206 return MF->getSubtarget<MCSubtargetInfo>();
209 void AsmPrinter::EmitToStreamer(MCStreamer &S, const MCInst &Inst) {
210 S.EmitInstruction(Inst, getSubtargetInfo());
213 /// getCurrentSection() - Return the current section we are emitting to.
214 const MCSection *AsmPrinter::getCurrentSection() const {
215 return OutStreamer->getCurrentSectionOnly();
218 void AsmPrinter::getAnalysisUsage(AnalysisUsage &AU) const {
219 AU.setPreservesAll();
220 MachineFunctionPass::getAnalysisUsage(AU);
221 AU.addRequired<MachineModuleInfo>();
222 AU.addRequired<MachineOptimizationRemarkEmitterPass>();
223 AU.addRequired<GCModuleInfo>();
225 AU.addRequired<MachineLoopInfo>();
228 bool AsmPrinter::doInitialization(Module &M) {
229 MMI = getAnalysisIfAvailable<MachineModuleInfo>();
231 // Initialize TargetLoweringObjectFile.
232 const_cast<TargetLoweringObjectFile&>(getObjFileLowering())
233 .Initialize(OutContext, TM);
235 OutStreamer->InitSections(false);
237 // Emit the version-min deplyment target directive if needed.
239 // FIXME: If we end up with a collection of these sorts of Darwin-specific
240 // or ELF-specific things, it may make sense to have a platform helper class
241 // that will work with the target helper class. For now keep it here, as the
242 // alternative is duplicated code in each of the target asm printers that
243 // use the directive, where it would need the same conditionalization
245 const Triple &TT = TM.getTargetTriple();
246 // If there is a version specified, Major will be non-zero.
247 if (TT.isOSDarwin() && TT.getOSMajorVersion() != 0) {
248 unsigned Major, Minor, Update;
249 MCVersionMinType VersionType;
250 if (TT.isWatchOS()) {
251 VersionType = MCVM_WatchOSVersionMin;
252 TT.getWatchOSVersion(Major, Minor, Update);
253 } else if (TT.isTvOS()) {
254 VersionType = MCVM_TvOSVersionMin;
255 TT.getiOSVersion(Major, Minor, Update);
256 } else if (TT.isMacOSX()) {
257 VersionType = MCVM_OSXVersionMin;
258 if (!TT.getMacOSXVersion(Major, Minor, Update))
261 VersionType = MCVM_IOSVersionMin;
262 TT.getiOSVersion(Major, Minor, Update);
265 OutStreamer->EmitVersionMin(VersionType, Major, Minor, Update);
268 // Allow the target to emit any magic that it wants at the start of the file.
269 EmitStartOfAsmFile(M);
271 // Very minimal debug info. It is ignored if we emit actual debug info. If we
272 // don't, this at least helps the user find where a global came from.
273 if (MAI->hasSingleParameterDotFile()) {
275 OutStreamer->EmitFileDirective(M.getSourceFileName());
278 GCModuleInfo *MI = getAnalysisIfAvailable<GCModuleInfo>();
279 assert(MI && "AsmPrinter didn't require GCModuleInfo?");
281 if (GCMetadataPrinter *MP = GetOrCreateGCPrinter(*I))
282 MP->beginAssembly(M, *MI, *this);
284 // Emit module-level inline asm if it exists.
285 if (!M.getModuleInlineAsm().empty()) {
286 // We're at the module level. Construct MCSubtarget from the default CPU
287 // and target triple.
288 std::unique_ptr<MCSubtargetInfo> STI(TM.getTarget().createMCSubtargetInfo(
289 TM.getTargetTriple().str(), TM.getTargetCPU(),
290 TM.getTargetFeatureString()));
291 OutStreamer->AddComment("Start of file scope inline assembly");
292 OutStreamer->AddBlankLine();
293 EmitInlineAsm(M.getModuleInlineAsm()+"\n",
294 OutContext.getSubtargetCopy(*STI), TM.Options.MCOptions);
295 OutStreamer->AddComment("End of file scope inline assembly");
296 OutStreamer->AddBlankLine();
299 if (MAI->doesSupportDebugInformation()) {
300 bool EmitCodeView = MMI->getModule()->getCodeViewFlag();
301 if (EmitCodeView && (TM.getTargetTriple().isKnownWindowsMSVCEnvironment() ||
302 TM.getTargetTriple().isWindowsItaniumEnvironment())) {
303 Handlers.push_back(HandlerInfo(new CodeViewDebug(this),
304 DbgTimerName, DbgTimerDescription,
305 CodeViewLineTablesGroupName,
306 CodeViewLineTablesGroupDescription));
308 if (!EmitCodeView || MMI->getModule()->getDwarfVersion()) {
309 DD = new DwarfDebug(this, &M);
311 Handlers.push_back(HandlerInfo(DD, DbgTimerName, DbgTimerDescription,
312 DWARFGroupName, DWARFGroupDescription));
316 switch (MAI->getExceptionHandlingType()) {
317 case ExceptionHandling::SjLj:
318 case ExceptionHandling::DwarfCFI:
319 case ExceptionHandling::ARM:
320 isCFIMoveForDebugging = true;
321 if (MAI->getExceptionHandlingType() != ExceptionHandling::DwarfCFI)
323 for (auto &F: M.getFunctionList()) {
324 // If the module contains any function with unwind data,
325 // .eh_frame has to be emitted.
326 // Ignore functions that won't get emitted.
327 if (!F.isDeclarationForLinker() && F.needsUnwindTableEntry()) {
328 isCFIMoveForDebugging = false;
334 isCFIMoveForDebugging = false;
338 EHStreamer *ES = nullptr;
339 switch (MAI->getExceptionHandlingType()) {
340 case ExceptionHandling::None:
342 case ExceptionHandling::SjLj:
343 case ExceptionHandling::DwarfCFI:
344 ES = new DwarfCFIException(this);
346 case ExceptionHandling::ARM:
347 ES = new ARMException(this);
349 case ExceptionHandling::WinEH:
350 switch (MAI->getWinEHEncodingType()) {
351 default: llvm_unreachable("unsupported unwinding information encoding");
352 case WinEH::EncodingType::Invalid:
354 case WinEH::EncodingType::X86:
355 case WinEH::EncodingType::Itanium:
356 ES = new WinException(this);
362 Handlers.push_back(HandlerInfo(ES, EHTimerName, EHTimerDescription,
363 DWARFGroupName, DWARFGroupDescription));
367 static bool canBeHidden(const GlobalValue *GV, const MCAsmInfo &MAI) {
368 if (!MAI.hasWeakDefCanBeHiddenDirective())
371 return canBeOmittedFromSymbolTable(GV);
374 void AsmPrinter::EmitLinkage(const GlobalValue *GV, MCSymbol *GVSym) const {
375 GlobalValue::LinkageTypes Linkage = GV->getLinkage();
377 case GlobalValue::CommonLinkage:
378 case GlobalValue::LinkOnceAnyLinkage:
379 case GlobalValue::LinkOnceODRLinkage:
380 case GlobalValue::WeakAnyLinkage:
381 case GlobalValue::WeakODRLinkage:
382 if (MAI->hasWeakDefDirective()) {
384 OutStreamer->EmitSymbolAttribute(GVSym, MCSA_Global);
386 if (!canBeHidden(GV, *MAI))
387 // .weak_definition _foo
388 OutStreamer->EmitSymbolAttribute(GVSym, MCSA_WeakDefinition);
390 OutStreamer->EmitSymbolAttribute(GVSym, MCSA_WeakDefAutoPrivate);
391 } else if (MAI->hasLinkOnceDirective()) {
393 OutStreamer->EmitSymbolAttribute(GVSym, MCSA_Global);
394 //NOTE: linkonce is handled by the section the symbol was assigned to.
397 OutStreamer->EmitSymbolAttribute(GVSym, MCSA_Weak);
400 case GlobalValue::ExternalLinkage:
401 // If external, declare as a global symbol: .globl _foo
402 OutStreamer->EmitSymbolAttribute(GVSym, MCSA_Global);
404 case GlobalValue::PrivateLinkage:
405 case GlobalValue::InternalLinkage:
407 case GlobalValue::AppendingLinkage:
408 case GlobalValue::AvailableExternallyLinkage:
409 case GlobalValue::ExternalWeakLinkage:
410 llvm_unreachable("Should never emit this");
412 llvm_unreachable("Unknown linkage type!");
415 void AsmPrinter::getNameWithPrefix(SmallVectorImpl<char> &Name,
416 const GlobalValue *GV) const {
417 TM.getNameWithPrefix(Name, GV, getObjFileLowering().getMangler());
420 MCSymbol *AsmPrinter::getSymbol(const GlobalValue *GV) const {
421 return TM.getSymbol(GV);
424 /// EmitGlobalVariable - Emit the specified global variable to the .s file.
425 void AsmPrinter::EmitGlobalVariable(const GlobalVariable *GV) {
426 bool IsEmuTLSVar = TM.Options.EmulatedTLS && GV->isThreadLocal();
427 assert(!(IsEmuTLSVar && GV->hasCommonLinkage()) &&
428 "No emulated TLS variables in the common section");
430 // Never emit TLS variable xyz in emulated TLS model.
431 // The initialization value is in __emutls_t.xyz instead of xyz.
435 if (GV->hasInitializer()) {
436 // Check to see if this is a special global used by LLVM, if so, emit it.
437 if (EmitSpecialLLVMGlobal(GV))
440 // Skip the emission of global equivalents. The symbol can be emitted later
441 // on by emitGlobalGOTEquivs in case it turns out to be needed.
442 if (GlobalGOTEquivs.count(getSymbol(GV)))
446 // When printing the control variable __emutls_v.*,
447 // we don't need to print the original TLS variable name.
448 GV->printAsOperand(OutStreamer->GetCommentOS(),
449 /*PrintType=*/false, GV->getParent());
450 OutStreamer->GetCommentOS() << '\n';
454 MCSymbol *GVSym = getSymbol(GV);
455 MCSymbol *EmittedSym = GVSym;
457 // getOrCreateEmuTLSControlSym only creates the symbol with name and default
459 // GV's or GVSym's attributes will be used for the EmittedSym.
460 EmitVisibility(EmittedSym, GV->getVisibility(), !GV->isDeclaration());
462 if (!GV->hasInitializer()) // External globals require no extra code.
465 GVSym->redefineIfPossible();
466 if (GVSym->isDefined() || GVSym->isVariable())
467 report_fatal_error("symbol '" + Twine(GVSym->getName()) +
468 "' is already defined");
470 if (MAI->hasDotTypeDotSizeDirective())
471 OutStreamer->EmitSymbolAttribute(EmittedSym, MCSA_ELF_TypeObject);
473 SectionKind GVKind = TargetLoweringObjectFile::getKindForGlobal(GV, TM);
475 const DataLayout &DL = GV->getParent()->getDataLayout();
476 uint64_t Size = DL.getTypeAllocSize(GV->getType()->getElementType());
478 // If the alignment is specified, we *must* obey it. Overaligning a global
479 // with a specified alignment is a prompt way to break globals emitted to
480 // sections and expected to be contiguous (e.g. ObjC metadata).
481 unsigned AlignLog = getGVAlignmentLog2(GV, DL);
483 for (const HandlerInfo &HI : Handlers) {
484 NamedRegionTimer T(HI.TimerName, HI.TimerDescription,
485 HI.TimerGroupName, HI.TimerGroupDescription,
486 TimePassesIsEnabled);
487 HI.Handler->setSymbolSize(GVSym, Size);
490 // Handle common symbols
491 if (GVKind.isCommon()) {
492 if (Size == 0) Size = 1; // .comm Foo, 0 is undefined, avoid it.
493 unsigned Align = 1 << AlignLog;
494 if (!getObjFileLowering().getCommDirectiveSupportsAlignment())
498 OutStreamer->EmitCommonSymbol(GVSym, Size, Align);
502 // Determine to which section this global should be emitted.
503 MCSection *TheSection = getObjFileLowering().SectionForGlobal(GV, GVKind, TM);
505 // If we have a bss global going to a section that supports the
506 // zerofill directive, do so here.
507 if (GVKind.isBSS() && MAI->hasMachoZeroFillDirective() &&
508 TheSection->isVirtualSection()) {
510 Size = 1; // zerofill of 0 bytes is undefined.
511 unsigned Align = 1 << AlignLog;
512 EmitLinkage(GV, GVSym);
513 // .zerofill __DATA, __bss, _foo, 400, 5
514 OutStreamer->EmitZerofill(TheSection, GVSym, Size, Align);
518 // If this is a BSS local symbol and we are emitting in the BSS
519 // section use .lcomm/.comm directive.
520 if (GVKind.isBSSLocal() &&
521 getObjFileLowering().getBSSSection() == TheSection) {
523 Size = 1; // .comm Foo, 0 is undefined, avoid it.
524 unsigned Align = 1 << AlignLog;
526 // Use .lcomm only if it supports user-specified alignment.
527 // Otherwise, while it would still be correct to use .lcomm in some
528 // cases (e.g. when Align == 1), the external assembler might enfore
529 // some -unknown- default alignment behavior, which could cause
530 // spurious differences between external and integrated assembler.
531 // Prefer to simply fall back to .local / .comm in this case.
532 if (MAI->getLCOMMDirectiveAlignmentType() != LCOMM::NoAlignment) {
534 OutStreamer->EmitLocalCommonSymbol(GVSym, Size, Align);
538 if (!getObjFileLowering().getCommDirectiveSupportsAlignment())
542 OutStreamer->EmitSymbolAttribute(GVSym, MCSA_Local);
544 OutStreamer->EmitCommonSymbol(GVSym, Size, Align);
548 // Handle thread local data for mach-o which requires us to output an
549 // additional structure of data and mangle the original symbol so that we
550 // can reference it later.
552 // TODO: This should become an "emit thread local global" method on TLOF.
553 // All of this macho specific stuff should be sunk down into TLOFMachO and
554 // stuff like "TLSExtraDataSection" should no longer be part of the parent
555 // TLOF class. This will also make it more obvious that stuff like
556 // MCStreamer::EmitTBSSSymbol is macho specific and only called from macho
558 if (GVKind.isThreadLocal() && MAI->hasMachoTBSSDirective()) {
559 // Emit the .tbss symbol
561 OutContext.getOrCreateSymbol(GVSym->getName() + Twine("$tlv$init"));
563 if (GVKind.isThreadBSS()) {
564 TheSection = getObjFileLowering().getTLSBSSSection();
565 OutStreamer->EmitTBSSSymbol(TheSection, MangSym, Size, 1 << AlignLog);
566 } else if (GVKind.isThreadData()) {
567 OutStreamer->SwitchSection(TheSection);
569 EmitAlignment(AlignLog, GV);
570 OutStreamer->EmitLabel(MangSym);
572 EmitGlobalConstant(GV->getParent()->getDataLayout(),
573 GV->getInitializer());
576 OutStreamer->AddBlankLine();
578 // Emit the variable struct for the runtime.
579 MCSection *TLVSect = getObjFileLowering().getTLSExtraDataSection();
581 OutStreamer->SwitchSection(TLVSect);
582 // Emit the linkage here.
583 EmitLinkage(GV, GVSym);
584 OutStreamer->EmitLabel(GVSym);
586 // Three pointers in size:
587 // - __tlv_bootstrap - used to make sure support exists
588 // - spare pointer, used when mapped by the runtime
589 // - pointer to mangled symbol above with initializer
590 unsigned PtrSize = DL.getPointerTypeSize(GV->getType());
591 OutStreamer->EmitSymbolValue(GetExternalSymbolSymbol("_tlv_bootstrap"),
593 OutStreamer->EmitIntValue(0, PtrSize);
594 OutStreamer->EmitSymbolValue(MangSym, PtrSize);
596 OutStreamer->AddBlankLine();
600 MCSymbol *EmittedInitSym = GVSym;
602 OutStreamer->SwitchSection(TheSection);
604 EmitLinkage(GV, EmittedInitSym);
605 EmitAlignment(AlignLog, GV);
607 OutStreamer->EmitLabel(EmittedInitSym);
609 EmitGlobalConstant(GV->getParent()->getDataLayout(), GV->getInitializer());
611 if (MAI->hasDotTypeDotSizeDirective())
613 OutStreamer->emitELFSize(EmittedInitSym,
614 MCConstantExpr::create(Size, OutContext));
616 OutStreamer->AddBlankLine();
619 /// Emit the directive and value for debug thread local expression
621 /// \p Value - The value to emit.
622 /// \p Size - The size of the integer (in bytes) to emit.
623 void AsmPrinter::EmitDebugThreadLocal(const MCExpr *Value,
624 unsigned Size) const {
625 OutStreamer->EmitValue(Value, Size);
628 /// EmitFunctionHeader - This method emits the header for the current
630 void AsmPrinter::EmitFunctionHeader() {
631 // Print out constants referenced by the function
634 // Print the 'header' of function.
635 const Function *F = MF->getFunction();
637 OutStreamer->SwitchSection(getObjFileLowering().SectionForGlobal(F, TM));
638 EmitVisibility(CurrentFnSym, F->getVisibility());
640 EmitLinkage(F, CurrentFnSym);
641 if (MAI->hasFunctionAlignment())
642 EmitAlignment(MF->getAlignment(), F);
644 if (MAI->hasDotTypeDotSizeDirective())
645 OutStreamer->EmitSymbolAttribute(CurrentFnSym, MCSA_ELF_TypeFunction);
648 F->printAsOperand(OutStreamer->GetCommentOS(),
649 /*PrintType=*/false, F->getParent());
650 OutStreamer->GetCommentOS() << '\n';
653 // Emit the prefix data.
654 if (F->hasPrefixData()) {
655 if (MAI->hasSubsectionsViaSymbols()) {
656 // Preserving prefix data on platforms which use subsections-via-symbols
657 // is a bit tricky. Here we introduce a symbol for the prefix data
658 // and use the .alt_entry attribute to mark the function's real entry point
659 // as an alternative entry point to the prefix-data symbol.
660 MCSymbol *PrefixSym = OutContext.createLinkerPrivateTempSymbol();
661 OutStreamer->EmitLabel(PrefixSym);
663 EmitGlobalConstant(F->getParent()->getDataLayout(), F->getPrefixData());
665 // Emit an .alt_entry directive for the actual function symbol.
666 OutStreamer->EmitSymbolAttribute(CurrentFnSym, MCSA_AltEntry);
668 EmitGlobalConstant(F->getParent()->getDataLayout(), F->getPrefixData());
672 // Emit the CurrentFnSym. This is a virtual function to allow targets to
673 // do their wild and crazy things as required.
674 EmitFunctionEntryLabel();
676 // If the function had address-taken blocks that got deleted, then we have
677 // references to the dangling symbols. Emit them at the start of the function
678 // so that we don't get references to undefined symbols.
679 std::vector<MCSymbol*> DeadBlockSyms;
680 MMI->takeDeletedSymbolsForFunction(F, DeadBlockSyms);
681 for (unsigned i = 0, e = DeadBlockSyms.size(); i != e; ++i) {
682 OutStreamer->AddComment("Address taken block that was later removed");
683 OutStreamer->EmitLabel(DeadBlockSyms[i]);
686 if (CurrentFnBegin) {
687 if (MAI->useAssignmentForEHBegin()) {
688 MCSymbol *CurPos = OutContext.createTempSymbol();
689 OutStreamer->EmitLabel(CurPos);
690 OutStreamer->EmitAssignment(CurrentFnBegin,
691 MCSymbolRefExpr::create(CurPos, OutContext));
693 OutStreamer->EmitLabel(CurrentFnBegin);
697 // Emit pre-function debug and/or EH information.
698 for (const HandlerInfo &HI : Handlers) {
699 NamedRegionTimer T(HI.TimerName, HI.TimerDescription, HI.TimerGroupName,
700 HI.TimerGroupDescription, TimePassesIsEnabled);
701 HI.Handler->beginFunction(MF);
704 // Emit the prologue data.
705 if (F->hasPrologueData())
706 EmitGlobalConstant(F->getParent()->getDataLayout(), F->getPrologueData());
709 /// EmitFunctionEntryLabel - Emit the label that is the entrypoint for the
710 /// function. This can be overridden by targets as required to do custom stuff.
711 void AsmPrinter::EmitFunctionEntryLabel() {
712 CurrentFnSym->redefineIfPossible();
714 // The function label could have already been emitted if two symbols end up
715 // conflicting due to asm renaming. Detect this and emit an error.
716 if (CurrentFnSym->isVariable())
717 report_fatal_error("'" + Twine(CurrentFnSym->getName()) +
718 "' is a protected alias");
719 if (CurrentFnSym->isDefined())
720 report_fatal_error("'" + Twine(CurrentFnSym->getName()) +
721 "' label emitted multiple times to assembly file");
723 return OutStreamer->EmitLabel(CurrentFnSym);
726 /// emitComments - Pretty-print comments for instructions.
727 static void emitComments(const MachineInstr &MI, raw_ostream &CommentOS,
729 const MachineFunction *MF = MI.getParent()->getParent();
730 const TargetInstrInfo *TII = MF->getSubtarget().getInstrInfo();
732 // Check for spills and reloads
735 const MachineFrameInfo &MFI = MF->getFrameInfo();
736 bool Commented = false;
738 // We assume a single instruction only has a spill or reload, not
740 const MachineMemOperand *MMO;
741 if (TII->isLoadFromStackSlotPostFE(MI, FI)) {
742 if (MFI.isSpillSlotObjectIndex(FI)) {
743 MMO = *MI.memoperands_begin();
744 CommentOS << MMO->getSize() << "-byte Reload";
747 } else if (TII->hasLoadFromStackSlot(MI, MMO, FI)) {
748 if (MFI.isSpillSlotObjectIndex(FI)) {
749 CommentOS << MMO->getSize() << "-byte Folded Reload";
752 } else if (TII->isStoreToStackSlotPostFE(MI, FI)) {
753 if (MFI.isSpillSlotObjectIndex(FI)) {
754 MMO = *MI.memoperands_begin();
755 CommentOS << MMO->getSize() << "-byte Spill";
758 } else if (TII->hasStoreToStackSlot(MI, MMO, FI)) {
759 if (MFI.isSpillSlotObjectIndex(FI)) {
760 CommentOS << MMO->getSize() << "-byte Folded Spill";
765 // Check for spill-induced copies
766 if (MI.getAsmPrinterFlag(MachineInstr::ReloadReuse)) {
768 CommentOS << " Reload Reuse";
771 if (Commented && AP->EnablePrintSchedInfo)
772 // If any comment was added above and we need sched info comment then
773 // add this new comment just after the above comment w/o "\n" between them.
774 CommentOS << " " << MF->getSubtarget().getSchedInfoStr(MI) << "\n";
779 /// emitImplicitDef - This method emits the specified machine instruction
780 /// that is an implicit def.
781 void AsmPrinter::emitImplicitDef(const MachineInstr *MI) const {
782 unsigned RegNo = MI->getOperand(0).getReg();
784 SmallString<128> Str;
785 raw_svector_ostream OS(Str);
786 OS << "implicit-def: "
787 << PrintReg(RegNo, MF->getSubtarget().getRegisterInfo());
789 OutStreamer->AddComment(OS.str());
790 OutStreamer->AddBlankLine();
793 static void emitKill(const MachineInstr *MI, AsmPrinter &AP) {
795 raw_string_ostream OS(Str);
797 for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
798 const MachineOperand &Op = MI->getOperand(i);
799 assert(Op.isReg() && "KILL instruction must have only register operands");
801 << PrintReg(Op.getReg(),
802 AP.MF->getSubtarget().getRegisterInfo())
803 << (Op.isDef() ? "<def>" : "<kill>");
805 AP.OutStreamer->AddComment(OS.str());
806 AP.OutStreamer->AddBlankLine();
809 /// emitDebugValueComment - This method handles the target-independent form
810 /// of DBG_VALUE, returning true if it was able to do so. A false return
811 /// means the target will need to handle MI in EmitInstruction.
812 static bool emitDebugValueComment(const MachineInstr *MI, AsmPrinter &AP) {
813 // This code handles only the 4-operand target-independent form.
814 if (MI->getNumOperands() != 4)
817 SmallString<128> Str;
818 raw_svector_ostream OS(Str);
819 OS << "DEBUG_VALUE: ";
821 const DILocalVariable *V = MI->getDebugVariable();
822 if (auto *SP = dyn_cast<DISubprogram>(V->getScope())) {
823 StringRef Name = SP->getDisplayName();
829 const DIExpression *Expr = MI->getDebugExpression();
830 auto Fragment = Expr->getFragmentInfo();
832 OS << " [fragment offset=" << Fragment->OffsetInBits
833 << " size=" << Fragment->SizeInBits << "]";
836 // The second operand is only an offset if it's an immediate.
838 bool MemLoc = MI->getOperand(0).isReg() && MI->getOperand(1).isImm();
839 int64_t Offset = MemLoc ? MI->getOperand(1).getImm() : 0;
840 for (unsigned i = 0; i < Expr->getNumElements(); ++i) {
841 uint64_t Op = Expr->getElement(i);
842 if (Op == dwarf::DW_OP_LLVM_fragment) {
843 // There can't be any operands after this in a valid expression
846 // We currently don't support extra Offsets or derefs after the first
847 // one. Bail out early instead of emitting an incorrect comment.
848 OS << " [complex expression]";
849 AP.OutStreamer->emitRawComment(OS.str());
851 } else if (Op == dwarf::DW_OP_deref) {
856 uint64_t ExtraOffset = Expr->getElement(i++);
857 if (Op == dwarf::DW_OP_plus)
858 Offset += ExtraOffset;
860 assert(Op == dwarf::DW_OP_minus);
861 Offset -= ExtraOffset;
865 // Register or immediate value. Register 0 means undef.
866 if (MI->getOperand(0).isFPImm()) {
867 APFloat APF = APFloat(MI->getOperand(0).getFPImm()->getValueAPF());
868 if (MI->getOperand(0).getFPImm()->getType()->isFloatTy()) {
869 OS << (double)APF.convertToFloat();
870 } else if (MI->getOperand(0).getFPImm()->getType()->isDoubleTy()) {
871 OS << APF.convertToDouble();
873 // There is no good way to print long double. Convert a copy to
874 // double. Ah well, it's only a comment.
876 APF.convert(APFloat::IEEEdouble(), APFloat::rmNearestTiesToEven,
878 OS << "(long double) " << APF.convertToDouble();
880 } else if (MI->getOperand(0).isImm()) {
881 OS << MI->getOperand(0).getImm();
882 } else if (MI->getOperand(0).isCImm()) {
883 MI->getOperand(0).getCImm()->getValue().print(OS, false /*isSigned*/);
886 if (MI->getOperand(0).isReg()) {
887 Reg = MI->getOperand(0).getReg();
889 assert(MI->getOperand(0).isFI() && "Unknown operand type");
890 const TargetFrameLowering *TFI = AP.MF->getSubtarget().getFrameLowering();
891 Offset += TFI->getFrameIndexReference(*AP.MF,
892 MI->getOperand(0).getIndex(), Reg);
896 // Suppress offset, it is not meaningful here.
898 // NOTE: Want this comment at start of line, don't emit with AddComment.
899 AP.OutStreamer->emitRawComment(OS.str());
904 OS << PrintReg(Reg, AP.MF->getSubtarget().getRegisterInfo());
908 OS << '+' << Offset << ']';
910 // NOTE: Want this comment at start of line, don't emit with AddComment.
911 AP.OutStreamer->emitRawComment(OS.str());
915 AsmPrinter::CFIMoveType AsmPrinter::needsCFIMoves() {
916 if (MAI->getExceptionHandlingType() == ExceptionHandling::DwarfCFI &&
917 MF->getFunction()->needsUnwindTableEntry())
920 if (MMI->hasDebugInfo())
926 bool AsmPrinter::needsSEHMoves() {
927 return MAI->usesWindowsCFI() && MF->getFunction()->needsUnwindTableEntry();
930 void AsmPrinter::emitCFIInstruction(const MachineInstr &MI) {
931 ExceptionHandling ExceptionHandlingType = MAI->getExceptionHandlingType();
932 if (ExceptionHandlingType != ExceptionHandling::DwarfCFI &&
933 ExceptionHandlingType != ExceptionHandling::ARM)
936 if (needsCFIMoves() == CFI_M_None)
939 const std::vector<MCCFIInstruction> &Instrs = MF->getFrameInstructions();
940 unsigned CFIIndex = MI.getOperand(0).getCFIIndex();
941 const MCCFIInstruction &CFI = Instrs[CFIIndex];
942 emitCFIInstruction(CFI);
945 void AsmPrinter::emitFrameAlloc(const MachineInstr &MI) {
946 // The operands are the MCSymbol and the frame offset of the allocation.
947 MCSymbol *FrameAllocSym = MI.getOperand(0).getMCSymbol();
948 int FrameOffset = MI.getOperand(1).getImm();
950 // Emit a symbol assignment.
951 OutStreamer->EmitAssignment(FrameAllocSym,
952 MCConstantExpr::create(FrameOffset, OutContext));
955 /// EmitFunctionBody - This method emits the body and trailer for a
957 void AsmPrinter::EmitFunctionBody() {
958 EmitFunctionHeader();
960 // Emit target-specific gunk before the function body.
961 EmitFunctionBodyStart();
963 bool ShouldPrintDebugScopes = MMI->hasDebugInfo();
965 // Print out code for the function.
966 bool HasAnyRealCode = false;
967 int NumInstsInFunction = 0;
968 for (auto &MBB : *MF) {
969 // Print a label for the basic block.
970 EmitBasicBlockStart(MBB);
971 for (auto &MI : MBB) {
973 // Print the assembly for the instruction.
974 if (!MI.isPosition() && !MI.isImplicitDef() && !MI.isKill() &&
975 !MI.isDebugValue()) {
976 HasAnyRealCode = true;
977 ++NumInstsInFunction;
980 if (ShouldPrintDebugScopes) {
981 for (const HandlerInfo &HI : Handlers) {
982 NamedRegionTimer T(HI.TimerName, HI.TimerDescription,
983 HI.TimerGroupName, HI.TimerGroupDescription,
984 TimePassesIsEnabled);
985 HI.Handler->beginInstruction(&MI);
990 emitComments(MI, OutStreamer->GetCommentOS(), this);
992 switch (MI.getOpcode()) {
993 case TargetOpcode::CFI_INSTRUCTION:
994 emitCFIInstruction(MI);
997 case TargetOpcode::LOCAL_ESCAPE:
1001 case TargetOpcode::EH_LABEL:
1002 case TargetOpcode::GC_LABEL:
1003 OutStreamer->EmitLabel(MI.getOperand(0).getMCSymbol());
1005 case TargetOpcode::INLINEASM:
1008 case TargetOpcode::DBG_VALUE:
1010 if (!emitDebugValueComment(&MI, *this))
1011 EmitInstruction(&MI);
1014 case TargetOpcode::IMPLICIT_DEF:
1015 if (isVerbose()) emitImplicitDef(&MI);
1017 case TargetOpcode::KILL:
1018 if (isVerbose()) emitKill(&MI, *this);
1021 EmitInstruction(&MI);
1025 if (ShouldPrintDebugScopes) {
1026 for (const HandlerInfo &HI : Handlers) {
1027 NamedRegionTimer T(HI.TimerName, HI.TimerDescription,
1028 HI.TimerGroupName, HI.TimerGroupDescription,
1029 TimePassesIsEnabled);
1030 HI.Handler->endInstruction();
1035 EmitBasicBlockEnd(MBB);
1038 EmittedInsts += NumInstsInFunction;
1039 MachineOptimizationRemarkAnalysis R(DEBUG_TYPE, "InstructionCount",
1040 MF->getFunction()->getSubprogram(),
1042 R << ore::NV("NumInstructions", NumInstsInFunction)
1043 << " instructions in function";
1046 // If the function is empty and the object file uses .subsections_via_symbols,
1047 // then we need to emit *something* to the function body to prevent the
1048 // labels from collapsing together. Just emit a noop.
1049 if ((MAI->hasSubsectionsViaSymbols() && !HasAnyRealCode)) {
1051 MF->getSubtarget().getInstrInfo()->getNoopForMachoTarget(Noop);
1052 OutStreamer->AddComment("avoids zero-length function");
1054 // Targets can opt-out of emitting the noop here by leaving the opcode
1056 if (Noop.getOpcode())
1057 OutStreamer->EmitInstruction(Noop, getSubtargetInfo());
1060 const Function *F = MF->getFunction();
1061 for (const auto &BB : *F) {
1062 if (!BB.hasAddressTaken())
1064 MCSymbol *Sym = GetBlockAddressSymbol(&BB);
1065 if (Sym->isDefined())
1067 OutStreamer->AddComment("Address of block that was removed by CodeGen");
1068 OutStreamer->EmitLabel(Sym);
1071 // Emit target-specific gunk after the function body.
1072 EmitFunctionBodyEnd();
1074 if (!MF->getLandingPads().empty() || MMI->hasDebugInfo() ||
1075 MF->hasEHFunclets() || MAI->hasDotTypeDotSizeDirective()) {
1076 // Create a symbol for the end of function.
1077 CurrentFnEnd = createTempSymbol("func_end");
1078 OutStreamer->EmitLabel(CurrentFnEnd);
1081 // If the target wants a .size directive for the size of the function, emit
1083 if (MAI->hasDotTypeDotSizeDirective()) {
1084 // We can get the size as difference between the function label and the
1086 const MCExpr *SizeExp = MCBinaryExpr::createSub(
1087 MCSymbolRefExpr::create(CurrentFnEnd, OutContext),
1088 MCSymbolRefExpr::create(CurrentFnSymForSize, OutContext), OutContext);
1089 OutStreamer->emitELFSize(CurrentFnSym, SizeExp);
1092 for (const HandlerInfo &HI : Handlers) {
1093 NamedRegionTimer T(HI.TimerName, HI.TimerDescription, HI.TimerGroupName,
1094 HI.TimerGroupDescription, TimePassesIsEnabled);
1095 HI.Handler->markFunctionEnd();
1098 // Print out jump tables referenced by the function.
1099 EmitJumpTableInfo();
1101 // Emit post-function debug and/or EH information.
1102 for (const HandlerInfo &HI : Handlers) {
1103 NamedRegionTimer T(HI.TimerName, HI.TimerDescription, HI.TimerGroupName,
1104 HI.TimerGroupDescription, TimePassesIsEnabled);
1105 HI.Handler->endFunction(MF);
1108 OutStreamer->AddBlankLine();
1111 /// \brief Compute the number of Global Variables that uses a Constant.
1112 static unsigned getNumGlobalVariableUses(const Constant *C) {
1116 if (isa<GlobalVariable>(C))
1119 unsigned NumUses = 0;
1120 for (auto *CU : C->users())
1121 NumUses += getNumGlobalVariableUses(dyn_cast<Constant>(CU));
1126 /// \brief Only consider global GOT equivalents if at least one user is a
1127 /// cstexpr inside an initializer of another global variables. Also, don't
1128 /// handle cstexpr inside instructions. During global variable emission,
1129 /// candidates are skipped and are emitted later in case at least one cstexpr
1130 /// isn't replaced by a PC relative GOT entry access.
1131 static bool isGOTEquivalentCandidate(const GlobalVariable *GV,
1132 unsigned &NumGOTEquivUsers) {
1133 // Global GOT equivalents are unnamed private globals with a constant
1134 // pointer initializer to another global symbol. They must point to a
1135 // GlobalVariable or Function, i.e., as GlobalValue.
1136 if (!GV->hasGlobalUnnamedAddr() || !GV->hasInitializer() ||
1137 !GV->isConstant() || !GV->isDiscardableIfUnused() ||
1138 !dyn_cast<GlobalValue>(GV->getOperand(0)))
1141 // To be a got equivalent, at least one of its users need to be a constant
1142 // expression used by another global variable.
1143 for (auto *U : GV->users())
1144 NumGOTEquivUsers += getNumGlobalVariableUses(dyn_cast<Constant>(U));
1146 return NumGOTEquivUsers > 0;
1149 /// \brief Unnamed constant global variables solely contaning a pointer to
1150 /// another globals variable is equivalent to a GOT table entry; it contains the
1151 /// the address of another symbol. Optimize it and replace accesses to these
1152 /// "GOT equivalents" by using the GOT entry for the final global instead.
1153 /// Compute GOT equivalent candidates among all global variables to avoid
1154 /// emitting them if possible later on, after it use is replaced by a GOT entry
1156 void AsmPrinter::computeGlobalGOTEquivs(Module &M) {
1157 if (!getObjFileLowering().supportIndirectSymViaGOTPCRel())
1160 for (const auto &G : M.globals()) {
1161 unsigned NumGOTEquivUsers = 0;
1162 if (!isGOTEquivalentCandidate(&G, NumGOTEquivUsers))
1165 const MCSymbol *GOTEquivSym = getSymbol(&G);
1166 GlobalGOTEquivs[GOTEquivSym] = std::make_pair(&G, NumGOTEquivUsers);
1170 /// \brief Constant expressions using GOT equivalent globals may not be eligible
1171 /// for PC relative GOT entry conversion, in such cases we need to emit such
1172 /// globals we previously omitted in EmitGlobalVariable.
1173 void AsmPrinter::emitGlobalGOTEquivs() {
1174 if (!getObjFileLowering().supportIndirectSymViaGOTPCRel())
1177 SmallVector<const GlobalVariable *, 8> FailedCandidates;
1178 for (auto &I : GlobalGOTEquivs) {
1179 const GlobalVariable *GV = I.second.first;
1180 unsigned Cnt = I.second.second;
1182 FailedCandidates.push_back(GV);
1184 GlobalGOTEquivs.clear();
1186 for (auto *GV : FailedCandidates)
1187 EmitGlobalVariable(GV);
1190 void AsmPrinter::emitGlobalIndirectSymbol(Module &M,
1191 const GlobalIndirectSymbol& GIS) {
1192 MCSymbol *Name = getSymbol(&GIS);
1194 if (GIS.hasExternalLinkage() || !MAI->getWeakRefDirective())
1195 OutStreamer->EmitSymbolAttribute(Name, MCSA_Global);
1196 else if (GIS.hasWeakLinkage() || GIS.hasLinkOnceLinkage())
1197 OutStreamer->EmitSymbolAttribute(Name, MCSA_WeakReference);
1199 assert(GIS.hasLocalLinkage() && "Invalid alias or ifunc linkage");
1201 // Set the symbol type to function if the alias has a function type.
1202 // This affects codegen when the aliasee is not a function.
1203 if (GIS.getType()->getPointerElementType()->isFunctionTy()) {
1204 OutStreamer->EmitSymbolAttribute(Name, MCSA_ELF_TypeFunction);
1205 if (isa<GlobalIFunc>(GIS))
1206 OutStreamer->EmitSymbolAttribute(Name, MCSA_ELF_TypeIndFunction);
1209 EmitVisibility(Name, GIS.getVisibility());
1211 const MCExpr *Expr = lowerConstant(GIS.getIndirectSymbol());
1213 if (isa<GlobalAlias>(&GIS) && MAI->hasAltEntry() && isa<MCBinaryExpr>(Expr))
1214 OutStreamer->EmitSymbolAttribute(Name, MCSA_AltEntry);
1216 // Emit the directives as assignments aka .set:
1217 OutStreamer->EmitAssignment(Name, Expr);
1219 if (auto *GA = dyn_cast<GlobalAlias>(&GIS)) {
1220 // If the aliasee does not correspond to a symbol in the output, i.e. the
1221 // alias is not of an object or the aliased object is private, then set the
1222 // size of the alias symbol from the type of the alias. We don't do this in
1223 // other situations as the alias and aliasee having differing types but same
1224 // size may be intentional.
1225 const GlobalObject *BaseObject = GA->getBaseObject();
1226 if (MAI->hasDotTypeDotSizeDirective() && GA->getValueType()->isSized() &&
1227 (!BaseObject || BaseObject->hasPrivateLinkage())) {
1228 const DataLayout &DL = M.getDataLayout();
1229 uint64_t Size = DL.getTypeAllocSize(GA->getValueType());
1230 OutStreamer->emitELFSize(Name, MCConstantExpr::create(Size, OutContext));
1235 bool AsmPrinter::doFinalization(Module &M) {
1236 // Set the MachineFunction to nullptr so that we can catch attempted
1237 // accesses to MF specific features at the module level and so that
1238 // we can conditionalize accesses based on whether or not it is nullptr.
1241 // Gather all GOT equivalent globals in the module. We really need two
1242 // passes over the globals: one to compute and another to avoid its emission
1243 // in EmitGlobalVariable, otherwise we would not be able to handle cases
1244 // where the got equivalent shows up before its use.
1245 computeGlobalGOTEquivs(M);
1247 // Emit global variables.
1248 for (const auto &G : M.globals())
1249 EmitGlobalVariable(&G);
1251 // Emit remaining GOT equivalent globals.
1252 emitGlobalGOTEquivs();
1254 // Emit visibility info for declarations
1255 for (const Function &F : M) {
1256 if (!F.isDeclarationForLinker())
1258 GlobalValue::VisibilityTypes V = F.getVisibility();
1259 if (V == GlobalValue::DefaultVisibility)
1262 MCSymbol *Name = getSymbol(&F);
1263 EmitVisibility(Name, V, false);
1266 const TargetLoweringObjectFile &TLOF = getObjFileLowering();
1268 // Emit module flags.
1269 SmallVector<Module::ModuleFlagEntry, 8> ModuleFlags;
1270 M.getModuleFlagsMetadata(ModuleFlags);
1271 if (!ModuleFlags.empty())
1272 TLOF.emitModuleFlags(*OutStreamer, ModuleFlags, TM);
1274 if (TM.getTargetTriple().isOSBinFormatELF()) {
1275 MachineModuleInfoELF &MMIELF = MMI->getObjFileInfo<MachineModuleInfoELF>();
1277 // Output stubs for external and common global variables.
1278 MachineModuleInfoELF::SymbolListTy Stubs = MMIELF.GetGVStubList();
1279 if (!Stubs.empty()) {
1280 OutStreamer->SwitchSection(TLOF.getDataSection());
1281 const DataLayout &DL = M.getDataLayout();
1283 for (const auto &Stub : Stubs) {
1284 OutStreamer->EmitLabel(Stub.first);
1285 OutStreamer->EmitSymbolValue(Stub.second.getPointer(),
1286 DL.getPointerSize());
1291 // Finalize debug and EH information.
1292 for (const HandlerInfo &HI : Handlers) {
1293 NamedRegionTimer T(HI.TimerName, HI.TimerDescription, HI.TimerGroupName,
1294 HI.TimerGroupDescription, TimePassesIsEnabled);
1295 HI.Handler->endModule();
1301 // If the target wants to know about weak references, print them all.
1302 if (MAI->getWeakRefDirective()) {
1303 // FIXME: This is not lazy, it would be nice to only print weak references
1304 // to stuff that is actually used. Note that doing so would require targets
1305 // to notice uses in operands (due to constant exprs etc). This should
1306 // happen with the MC stuff eventually.
1308 // Print out module-level global objects here.
1309 for (const auto &GO : M.global_objects()) {
1310 if (!GO.hasExternalWeakLinkage())
1312 OutStreamer->EmitSymbolAttribute(getSymbol(&GO), MCSA_WeakReference);
1316 OutStreamer->AddBlankLine();
1318 // Print aliases in topological order, that is, for each alias a = b,
1319 // b must be printed before a.
1320 // This is because on some targets (e.g. PowerPC) linker expects aliases in
1321 // such an order to generate correct TOC information.
1322 SmallVector<const GlobalAlias *, 16> AliasStack;
1323 SmallPtrSet<const GlobalAlias *, 16> AliasVisited;
1324 for (const auto &Alias : M.aliases()) {
1325 for (const GlobalAlias *Cur = &Alias; Cur;
1326 Cur = dyn_cast<GlobalAlias>(Cur->getAliasee())) {
1327 if (!AliasVisited.insert(Cur).second)
1329 AliasStack.push_back(Cur);
1331 for (const GlobalAlias *AncestorAlias : llvm::reverse(AliasStack))
1332 emitGlobalIndirectSymbol(M, *AncestorAlias);
1335 for (const auto &IFunc : M.ifuncs())
1336 emitGlobalIndirectSymbol(M, IFunc);
1338 GCModuleInfo *MI = getAnalysisIfAvailable<GCModuleInfo>();
1339 assert(MI && "AsmPrinter didn't require GCModuleInfo?");
1340 for (GCModuleInfo::iterator I = MI->end(), E = MI->begin(); I != E; )
1341 if (GCMetadataPrinter *MP = GetOrCreateGCPrinter(**--I))
1342 MP->finishAssembly(M, *MI, *this);
1344 // Emit llvm.ident metadata in an '.ident' directive.
1345 EmitModuleIdents(M);
1347 // Emit __morestack address if needed for indirect calls.
1348 if (MMI->usesMorestackAddr()) {
1350 MCSection *ReadOnlySection = getObjFileLowering().getSectionForConstant(
1351 getDataLayout(), SectionKind::getReadOnly(),
1352 /*C=*/nullptr, Align);
1353 OutStreamer->SwitchSection(ReadOnlySection);
1355 MCSymbol *AddrSymbol =
1356 OutContext.getOrCreateSymbol(StringRef("__morestack_addr"));
1357 OutStreamer->EmitLabel(AddrSymbol);
1359 unsigned PtrSize = MAI->getCodePointerSize();
1360 OutStreamer->EmitSymbolValue(GetExternalSymbolSymbol("__morestack"),
1364 // If we don't have any trampolines, then we don't require stack memory
1365 // to be executable. Some targets have a directive to declare this.
1366 Function *InitTrampolineIntrinsic = M.getFunction("llvm.init.trampoline");
1367 if (!InitTrampolineIntrinsic || InitTrampolineIntrinsic->use_empty())
1368 if (MCSection *S = MAI->getNonexecutableStackSection(OutContext))
1369 OutStreamer->SwitchSection(S);
1371 // Allow the target to emit any magic that it wants at the end of the file,
1372 // after everything else has gone out.
1373 EmitEndOfAsmFile(M);
1377 OutStreamer->Finish();
1378 OutStreamer->reset();
1383 MCSymbol *AsmPrinter::getCurExceptionSym() {
1384 if (!CurExceptionSym)
1385 CurExceptionSym = createTempSymbol("exception");
1386 return CurExceptionSym;
1389 void AsmPrinter::SetupMachineFunction(MachineFunction &MF) {
1391 // Get the function symbol.
1392 CurrentFnSym = getSymbol(MF.getFunction());
1393 CurrentFnSymForSize = CurrentFnSym;
1394 CurrentFnBegin = nullptr;
1395 CurExceptionSym = nullptr;
1396 bool NeedsLocalForSize = MAI->needsLocalForSize();
1397 if (!MF.getLandingPads().empty() || MMI->hasDebugInfo() ||
1398 MF.hasEHFunclets() || NeedsLocalForSize) {
1399 CurrentFnBegin = createTempSymbol("func_begin");
1400 if (NeedsLocalForSize)
1401 CurrentFnSymForSize = CurrentFnBegin;
1404 ORE = &getAnalysis<MachineOptimizationRemarkEmitterPass>().getORE();
1406 LI = &getAnalysis<MachineLoopInfo>();
1408 const TargetSubtargetInfo &STI = MF.getSubtarget();
1409 EnablePrintSchedInfo = PrintSchedule.getNumOccurrences()
1411 : STI.supportPrintSchedInfo();
1416 // Keep track the alignment, constpool entries per Section.
1420 SmallVector<unsigned, 4> CPEs;
1422 SectionCPs(MCSection *s, unsigned a) : S(s), Alignment(a) {}
1425 } // end anonymous namespace
1427 /// EmitConstantPool - Print to the current output stream assembly
1428 /// representations of the constants in the constant pool MCP. This is
1429 /// used to print out constants which have been "spilled to memory" by
1430 /// the code generator.
1432 void AsmPrinter::EmitConstantPool() {
1433 const MachineConstantPool *MCP = MF->getConstantPool();
1434 const std::vector<MachineConstantPoolEntry> &CP = MCP->getConstants();
1435 if (CP.empty()) return;
1437 // Calculate sections for constant pool entries. We collect entries to go into
1438 // the same section together to reduce amount of section switch statements.
1439 SmallVector<SectionCPs, 4> CPSections;
1440 for (unsigned i = 0, e = CP.size(); i != e; ++i) {
1441 const MachineConstantPoolEntry &CPE = CP[i];
1442 unsigned Align = CPE.getAlignment();
1444 SectionKind Kind = CPE.getSectionKind(&getDataLayout());
1446 const Constant *C = nullptr;
1447 if (!CPE.isMachineConstantPoolEntry())
1448 C = CPE.Val.ConstVal;
1450 MCSection *S = getObjFileLowering().getSectionForConstant(getDataLayout(),
1453 // The number of sections are small, just do a linear search from the
1454 // last section to the first.
1456 unsigned SecIdx = CPSections.size();
1457 while (SecIdx != 0) {
1458 if (CPSections[--SecIdx].S == S) {
1464 SecIdx = CPSections.size();
1465 CPSections.push_back(SectionCPs(S, Align));
1468 if (Align > CPSections[SecIdx].Alignment)
1469 CPSections[SecIdx].Alignment = Align;
1470 CPSections[SecIdx].CPEs.push_back(i);
1473 // Now print stuff into the calculated sections.
1474 const MCSection *CurSection = nullptr;
1475 unsigned Offset = 0;
1476 for (unsigned i = 0, e = CPSections.size(); i != e; ++i) {
1477 for (unsigned j = 0, ee = CPSections[i].CPEs.size(); j != ee; ++j) {
1478 unsigned CPI = CPSections[i].CPEs[j];
1479 MCSymbol *Sym = GetCPISymbol(CPI);
1480 if (!Sym->isUndefined())
1483 if (CurSection != CPSections[i].S) {
1484 OutStreamer->SwitchSection(CPSections[i].S);
1485 EmitAlignment(Log2_32(CPSections[i].Alignment));
1486 CurSection = CPSections[i].S;
1490 MachineConstantPoolEntry CPE = CP[CPI];
1492 // Emit inter-object padding for alignment.
1493 unsigned AlignMask = CPE.getAlignment() - 1;
1494 unsigned NewOffset = (Offset + AlignMask) & ~AlignMask;
1495 OutStreamer->EmitZeros(NewOffset - Offset);
1497 Type *Ty = CPE.getType();
1498 Offset = NewOffset + getDataLayout().getTypeAllocSize(Ty);
1500 OutStreamer->EmitLabel(Sym);
1501 if (CPE.isMachineConstantPoolEntry())
1502 EmitMachineConstantPoolValue(CPE.Val.MachineCPVal);
1504 EmitGlobalConstant(getDataLayout(), CPE.Val.ConstVal);
1509 /// EmitJumpTableInfo - Print assembly representations of the jump tables used
1510 /// by the current function to the current output stream.
1512 void AsmPrinter::EmitJumpTableInfo() {
1513 const DataLayout &DL = MF->getDataLayout();
1514 const MachineJumpTableInfo *MJTI = MF->getJumpTableInfo();
1516 if (MJTI->getEntryKind() == MachineJumpTableInfo::EK_Inline) return;
1517 const std::vector<MachineJumpTableEntry> &JT = MJTI->getJumpTables();
1518 if (JT.empty()) return;
1520 // Pick the directive to use to print the jump table entries, and switch to
1521 // the appropriate section.
1522 const Function *F = MF->getFunction();
1523 const TargetLoweringObjectFile &TLOF = getObjFileLowering();
1524 bool JTInDiffSection = !TLOF.shouldPutJumpTableInFunctionSection(
1525 MJTI->getEntryKind() == MachineJumpTableInfo::EK_LabelDifference32,
1527 if (JTInDiffSection) {
1528 // Drop it in the readonly section.
1529 MCSection *ReadOnlySection = TLOF.getSectionForJumpTable(*F, TM);
1530 OutStreamer->SwitchSection(ReadOnlySection);
1533 EmitAlignment(Log2_32(MJTI->getEntryAlignment(DL)));
1535 // Jump tables in code sections are marked with a data_region directive
1536 // where that's supported.
1537 if (!JTInDiffSection)
1538 OutStreamer->EmitDataRegion(MCDR_DataRegionJT32);
1540 for (unsigned JTI = 0, e = JT.size(); JTI != e; ++JTI) {
1541 const std::vector<MachineBasicBlock*> &JTBBs = JT[JTI].MBBs;
1543 // If this jump table was deleted, ignore it.
1544 if (JTBBs.empty()) continue;
1546 // For the EK_LabelDifference32 entry, if using .set avoids a relocation,
1547 /// emit a .set directive for each unique entry.
1548 if (MJTI->getEntryKind() == MachineJumpTableInfo::EK_LabelDifference32 &&
1549 MAI->doesSetDirectiveSuppressReloc()) {
1550 SmallPtrSet<const MachineBasicBlock*, 16> EmittedSets;
1551 const TargetLowering *TLI = MF->getSubtarget().getTargetLowering();
1552 const MCExpr *Base = TLI->getPICJumpTableRelocBaseExpr(MF,JTI,OutContext);
1553 for (unsigned ii = 0, ee = JTBBs.size(); ii != ee; ++ii) {
1554 const MachineBasicBlock *MBB = JTBBs[ii];
1555 if (!EmittedSets.insert(MBB).second)
1558 // .set LJTSet, LBB32-base
1560 MCSymbolRefExpr::create(MBB->getSymbol(), OutContext);
1561 OutStreamer->EmitAssignment(GetJTSetSymbol(JTI, MBB->getNumber()),
1562 MCBinaryExpr::createSub(LHS, Base,
1567 // On some targets (e.g. Darwin) we want to emit two consecutive labels
1568 // before each jump table. The first label is never referenced, but tells
1569 // the assembler and linker the extents of the jump table object. The
1570 // second label is actually referenced by the code.
1571 if (JTInDiffSection && DL.hasLinkerPrivateGlobalPrefix())
1572 // FIXME: This doesn't have to have any specific name, just any randomly
1573 // named and numbered 'l' label would work. Simplify GetJTISymbol.
1574 OutStreamer->EmitLabel(GetJTISymbol(JTI, true));
1576 OutStreamer->EmitLabel(GetJTISymbol(JTI));
1578 for (unsigned ii = 0, ee = JTBBs.size(); ii != ee; ++ii)
1579 EmitJumpTableEntry(MJTI, JTBBs[ii], JTI);
1581 if (!JTInDiffSection)
1582 OutStreamer->EmitDataRegion(MCDR_DataRegionEnd);
1585 /// EmitJumpTableEntry - Emit a jump table entry for the specified MBB to the
1587 void AsmPrinter::EmitJumpTableEntry(const MachineJumpTableInfo *MJTI,
1588 const MachineBasicBlock *MBB,
1589 unsigned UID) const {
1590 assert(MBB && MBB->getNumber() >= 0 && "Invalid basic block");
1591 const MCExpr *Value = nullptr;
1592 switch (MJTI->getEntryKind()) {
1593 case MachineJumpTableInfo::EK_Inline:
1594 llvm_unreachable("Cannot emit EK_Inline jump table entry");
1595 case MachineJumpTableInfo::EK_Custom32:
1596 Value = MF->getSubtarget().getTargetLowering()->LowerCustomJumpTableEntry(
1597 MJTI, MBB, UID, OutContext);
1599 case MachineJumpTableInfo::EK_BlockAddress:
1600 // EK_BlockAddress - Each entry is a plain address of block, e.g.:
1602 Value = MCSymbolRefExpr::create(MBB->getSymbol(), OutContext);
1604 case MachineJumpTableInfo::EK_GPRel32BlockAddress: {
1605 // EK_GPRel32BlockAddress - Each entry is an address of block, encoded
1606 // with a relocation as gp-relative, e.g.:
1608 MCSymbol *MBBSym = MBB->getSymbol();
1609 OutStreamer->EmitGPRel32Value(MCSymbolRefExpr::create(MBBSym, OutContext));
1613 case MachineJumpTableInfo::EK_GPRel64BlockAddress: {
1614 // EK_GPRel64BlockAddress - Each entry is an address of block, encoded
1615 // with a relocation as gp-relative, e.g.:
1617 MCSymbol *MBBSym = MBB->getSymbol();
1618 OutStreamer->EmitGPRel64Value(MCSymbolRefExpr::create(MBBSym, OutContext));
1622 case MachineJumpTableInfo::EK_LabelDifference32: {
1623 // Each entry is the address of the block minus the address of the jump
1624 // table. This is used for PIC jump tables where gprel32 is not supported.
1626 // .word LBB123 - LJTI1_2
1627 // If the .set directive avoids relocations, this is emitted as:
1628 // .set L4_5_set_123, LBB123 - LJTI1_2
1629 // .word L4_5_set_123
1630 if (MAI->doesSetDirectiveSuppressReloc()) {
1631 Value = MCSymbolRefExpr::create(GetJTSetSymbol(UID, MBB->getNumber()),
1635 Value = MCSymbolRefExpr::create(MBB->getSymbol(), OutContext);
1636 const TargetLowering *TLI = MF->getSubtarget().getTargetLowering();
1637 const MCExpr *Base = TLI->getPICJumpTableRelocBaseExpr(MF, UID, OutContext);
1638 Value = MCBinaryExpr::createSub(Value, Base, OutContext);
1643 assert(Value && "Unknown entry kind!");
1645 unsigned EntrySize = MJTI->getEntrySize(getDataLayout());
1646 OutStreamer->EmitValue(Value, EntrySize);
1649 /// EmitSpecialLLVMGlobal - Check to see if the specified global is a
1650 /// special global used by LLVM. If so, emit it and return true, otherwise
1651 /// do nothing and return false.
1652 bool AsmPrinter::EmitSpecialLLVMGlobal(const GlobalVariable *GV) {
1653 if (GV->getName() == "llvm.used") {
1654 if (MAI->hasNoDeadStrip()) // No need to emit this at all.
1655 EmitLLVMUsedList(cast<ConstantArray>(GV->getInitializer()));
1659 // Ignore debug and non-emitted data. This handles llvm.compiler.used.
1660 if (GV->getSection() == "llvm.metadata" ||
1661 GV->hasAvailableExternallyLinkage())
1664 if (!GV->hasAppendingLinkage()) return false;
1666 assert(GV->hasInitializer() && "Not a special LLVM global!");
1668 if (GV->getName() == "llvm.global_ctors") {
1669 EmitXXStructorList(GV->getParent()->getDataLayout(), GV->getInitializer(),
1675 if (GV->getName() == "llvm.global_dtors") {
1676 EmitXXStructorList(GV->getParent()->getDataLayout(), GV->getInitializer(),
1677 /* isCtor */ false);
1682 report_fatal_error("unknown special variable");
1685 /// EmitLLVMUsedList - For targets that define a MAI::UsedDirective, mark each
1686 /// global in the specified llvm.used list for which emitUsedDirectiveFor
1687 /// is true, as being used with this directive.
1688 void AsmPrinter::EmitLLVMUsedList(const ConstantArray *InitList) {
1689 // Should be an array of 'i8*'.
1690 for (unsigned i = 0, e = InitList->getNumOperands(); i != e; ++i) {
1691 const GlobalValue *GV =
1692 dyn_cast<GlobalValue>(InitList->getOperand(i)->stripPointerCasts());
1694 OutStreamer->EmitSymbolAttribute(getSymbol(GV), MCSA_NoDeadStrip);
1702 Constant *Func = nullptr;
1703 GlobalValue *ComdatKey = nullptr;
1705 Structor() = default;
1708 } // end anonymous namespace
1710 /// EmitXXStructorList - Emit the ctor or dtor list taking into account the init
1712 void AsmPrinter::EmitXXStructorList(const DataLayout &DL, const Constant *List,
1714 // Should be an array of '{ int, void ()* }' structs. The first value is the
1716 if (!isa<ConstantArray>(List)) return;
1718 // Sanity check the structors list.
1719 const ConstantArray *InitList = dyn_cast<ConstantArray>(List);
1720 if (!InitList) return; // Not an array!
1721 StructType *ETy = dyn_cast<StructType>(InitList->getType()->getElementType());
1722 // FIXME: Only allow the 3-field form in LLVM 4.0.
1723 if (!ETy || ETy->getNumElements() < 2 || ETy->getNumElements() > 3)
1724 return; // Not an array of two or three elements!
1725 if (!isa<IntegerType>(ETy->getTypeAtIndex(0U)) ||
1726 !isa<PointerType>(ETy->getTypeAtIndex(1U))) return; // Not (int, ptr).
1727 if (ETy->getNumElements() == 3 && !isa<PointerType>(ETy->getTypeAtIndex(2U)))
1728 return; // Not (int, ptr, ptr).
1730 // Gather the structors in a form that's convenient for sorting by priority.
1731 SmallVector<Structor, 8> Structors;
1732 for (Value *O : InitList->operands()) {
1733 ConstantStruct *CS = dyn_cast<ConstantStruct>(O);
1734 if (!CS) continue; // Malformed.
1735 if (CS->getOperand(1)->isNullValue())
1736 break; // Found a null terminator, skip the rest.
1737 ConstantInt *Priority = dyn_cast<ConstantInt>(CS->getOperand(0));
1738 if (!Priority) continue; // Malformed.
1739 Structors.push_back(Structor());
1740 Structor &S = Structors.back();
1741 S.Priority = Priority->getLimitedValue(65535);
1742 S.Func = CS->getOperand(1);
1743 if (ETy->getNumElements() == 3 && !CS->getOperand(2)->isNullValue())
1745 dyn_cast<GlobalValue>(CS->getOperand(2)->stripPointerCasts());
1748 // Emit the function pointers in the target-specific order
1749 unsigned Align = Log2_32(DL.getPointerPrefAlignment());
1750 std::stable_sort(Structors.begin(), Structors.end(),
1751 [](const Structor &L,
1752 const Structor &R) { return L.Priority < R.Priority; });
1753 for (Structor &S : Structors) {
1754 const TargetLoweringObjectFile &Obj = getObjFileLowering();
1755 const MCSymbol *KeySym = nullptr;
1756 if (GlobalValue *GV = S.ComdatKey) {
1757 if (GV->isDeclarationForLinker())
1758 // If the associated variable is not defined in this module
1759 // (it might be available_externally, or have been an
1760 // available_externally definition that was dropped by the
1761 // EliminateAvailableExternally pass), some other TU
1762 // will provide its dynamic initializer.
1765 KeySym = getSymbol(GV);
1767 MCSection *OutputSection =
1768 (isCtor ? Obj.getStaticCtorSection(S.Priority, KeySym)
1769 : Obj.getStaticDtorSection(S.Priority, KeySym));
1770 OutStreamer->SwitchSection(OutputSection);
1771 if (OutStreamer->getCurrentSection() != OutStreamer->getPreviousSection())
1772 EmitAlignment(Align);
1773 EmitXXStructor(DL, S.Func);
1777 void AsmPrinter::EmitModuleIdents(Module &M) {
1778 if (!MAI->hasIdentDirective())
1781 if (const NamedMDNode *NMD = M.getNamedMetadata("llvm.ident")) {
1782 for (unsigned i = 0, e = NMD->getNumOperands(); i != e; ++i) {
1783 const MDNode *N = NMD->getOperand(i);
1784 assert(N->getNumOperands() == 1 &&
1785 "llvm.ident metadata entry can have only one operand");
1786 const MDString *S = cast<MDString>(N->getOperand(0));
1787 OutStreamer->EmitIdent(S->getString());
1792 //===--------------------------------------------------------------------===//
1793 // Emission and print routines
1796 /// EmitInt8 - Emit a byte directive and value.
1798 void AsmPrinter::EmitInt8(int Value) const {
1799 OutStreamer->EmitIntValue(Value, 1);
1802 /// EmitInt16 - Emit a short directive and value.
1804 void AsmPrinter::EmitInt16(int Value) const {
1805 OutStreamer->EmitIntValue(Value, 2);
1808 /// EmitInt32 - Emit a long directive and value.
1810 void AsmPrinter::EmitInt32(int Value) const {
1811 OutStreamer->EmitIntValue(Value, 4);
1814 /// Emit something like ".long Hi-Lo" where the size in bytes of the directive
1815 /// is specified by Size and Hi/Lo specify the labels. This implicitly uses
1816 /// .set if it avoids relocations.
1817 void AsmPrinter::EmitLabelDifference(const MCSymbol *Hi, const MCSymbol *Lo,
1818 unsigned Size) const {
1819 OutStreamer->emitAbsoluteSymbolDiff(Hi, Lo, Size);
1822 /// EmitLabelPlusOffset - Emit something like ".long Label+Offset"
1823 /// where the size in bytes of the directive is specified by Size and Label
1824 /// specifies the label. This implicitly uses .set if it is available.
1825 void AsmPrinter::EmitLabelPlusOffset(const MCSymbol *Label, uint64_t Offset,
1827 bool IsSectionRelative) const {
1828 if (MAI->needsDwarfSectionOffsetDirective() && IsSectionRelative) {
1829 OutStreamer->EmitCOFFSecRel32(Label, Offset);
1831 OutStreamer->EmitZeros(Size - 4);
1835 // Emit Label+Offset (or just Label if Offset is zero)
1836 const MCExpr *Expr = MCSymbolRefExpr::create(Label, OutContext);
1838 Expr = MCBinaryExpr::createAdd(
1839 Expr, MCConstantExpr::create(Offset, OutContext), OutContext);
1841 OutStreamer->EmitValue(Expr, Size);
1844 //===----------------------------------------------------------------------===//
1846 // EmitAlignment - Emit an alignment directive to the specified power of
1847 // two boundary. For example, if you pass in 3 here, you will get an 8
1848 // byte alignment. If a global value is specified, and if that global has
1849 // an explicit alignment requested, it will override the alignment request
1850 // if required for correctness.
1852 void AsmPrinter::EmitAlignment(unsigned NumBits, const GlobalObject *GV) const {
1854 NumBits = getGVAlignmentLog2(GV, GV->getParent()->getDataLayout(), NumBits);
1856 if (NumBits == 0) return; // 1-byte aligned: no need to emit alignment.
1859 static_cast<unsigned>(std::numeric_limits<unsigned>::digits) &&
1860 "undefined behavior");
1861 if (getCurrentSection()->getKind().isText())
1862 OutStreamer->EmitCodeAlignment(1u << NumBits);
1864 OutStreamer->EmitValueToAlignment(1u << NumBits);
1867 //===----------------------------------------------------------------------===//
1868 // Constant emission.
1869 //===----------------------------------------------------------------------===//
1871 const MCExpr *AsmPrinter::lowerConstant(const Constant *CV) {
1872 MCContext &Ctx = OutContext;
1874 if (CV->isNullValue() || isa<UndefValue>(CV))
1875 return MCConstantExpr::create(0, Ctx);
1877 if (const ConstantInt *CI = dyn_cast<ConstantInt>(CV))
1878 return MCConstantExpr::create(CI->getZExtValue(), Ctx);
1880 if (const GlobalValue *GV = dyn_cast<GlobalValue>(CV))
1881 return MCSymbolRefExpr::create(getSymbol(GV), Ctx);
1883 if (const BlockAddress *BA = dyn_cast<BlockAddress>(CV))
1884 return MCSymbolRefExpr::create(GetBlockAddressSymbol(BA), Ctx);
1886 const ConstantExpr *CE = dyn_cast<ConstantExpr>(CV);
1888 llvm_unreachable("Unknown constant value to lower!");
1891 switch (CE->getOpcode()) {
1893 // If the code isn't optimized, there may be outstanding folding
1894 // opportunities. Attempt to fold the expression using DataLayout as a
1895 // last resort before giving up.
1896 if (Constant *C = ConstantFoldConstant(CE, getDataLayout()))
1898 return lowerConstant(C);
1900 // Otherwise report the problem to the user.
1903 raw_string_ostream OS(S);
1904 OS << "Unsupported expression in static initializer: ";
1905 CE->printAsOperand(OS, /*PrintType=*/false,
1906 !MF ? nullptr : MF->getFunction()->getParent());
1907 report_fatal_error(OS.str());
1909 case Instruction::GetElementPtr: {
1910 // Generate a symbolic expression for the byte address
1911 APInt OffsetAI(getDataLayout().getPointerTypeSizeInBits(CE->getType()), 0);
1912 cast<GEPOperator>(CE)->accumulateConstantOffset(getDataLayout(), OffsetAI);
1914 const MCExpr *Base = lowerConstant(CE->getOperand(0));
1918 int64_t Offset = OffsetAI.getSExtValue();
1919 return MCBinaryExpr::createAdd(Base, MCConstantExpr::create(Offset, Ctx),
1923 case Instruction::Trunc:
1924 // We emit the value and depend on the assembler to truncate the generated
1925 // expression properly. This is important for differences between
1926 // blockaddress labels. Since the two labels are in the same function, it
1927 // is reasonable to treat their delta as a 32-bit value.
1929 case Instruction::BitCast:
1930 return lowerConstant(CE->getOperand(0));
1932 case Instruction::IntToPtr: {
1933 const DataLayout &DL = getDataLayout();
1935 // Handle casts to pointers by changing them into casts to the appropriate
1936 // integer type. This promotes constant folding and simplifies this code.
1937 Constant *Op = CE->getOperand(0);
1938 Op = ConstantExpr::getIntegerCast(Op, DL.getIntPtrType(CV->getType()),
1940 return lowerConstant(Op);
1943 case Instruction::PtrToInt: {
1944 const DataLayout &DL = getDataLayout();
1946 // Support only foldable casts to/from pointers that can be eliminated by
1947 // changing the pointer to the appropriately sized integer type.
1948 Constant *Op = CE->getOperand(0);
1949 Type *Ty = CE->getType();
1951 const MCExpr *OpExpr = lowerConstant(Op);
1953 // We can emit the pointer value into this slot if the slot is an
1954 // integer slot equal to the size of the pointer.
1955 if (DL.getTypeAllocSize(Ty) == DL.getTypeAllocSize(Op->getType()))
1958 // Otherwise the pointer is smaller than the resultant integer, mask off
1959 // the high bits so we are sure to get a proper truncation if the input is
1961 unsigned InBits = DL.getTypeAllocSizeInBits(Op->getType());
1962 const MCExpr *MaskExpr = MCConstantExpr::create(~0ULL >> (64-InBits), Ctx);
1963 return MCBinaryExpr::createAnd(OpExpr, MaskExpr, Ctx);
1966 case Instruction::Sub: {
1969 if (IsConstantOffsetFromGlobal(CE->getOperand(0), LHSGV, LHSOffset,
1973 if (IsConstantOffsetFromGlobal(CE->getOperand(1), RHSGV, RHSOffset,
1975 const MCExpr *RelocExpr =
1976 getObjFileLowering().lowerRelativeReference(LHSGV, RHSGV, TM);
1978 RelocExpr = MCBinaryExpr::createSub(
1979 MCSymbolRefExpr::create(getSymbol(LHSGV), Ctx),
1980 MCSymbolRefExpr::create(getSymbol(RHSGV), Ctx), Ctx);
1981 int64_t Addend = (LHSOffset - RHSOffset).getSExtValue();
1983 RelocExpr = MCBinaryExpr::createAdd(
1984 RelocExpr, MCConstantExpr::create(Addend, Ctx), Ctx);
1991 // The MC library also has a right-shift operator, but it isn't consistently
1992 // signed or unsigned between different targets.
1993 case Instruction::Add:
1994 case Instruction::Mul:
1995 case Instruction::SDiv:
1996 case Instruction::SRem:
1997 case Instruction::Shl:
1998 case Instruction::And:
1999 case Instruction::Or:
2000 case Instruction::Xor: {
2001 const MCExpr *LHS = lowerConstant(CE->getOperand(0));
2002 const MCExpr *RHS = lowerConstant(CE->getOperand(1));
2003 switch (CE->getOpcode()) {
2004 default: llvm_unreachable("Unknown binary operator constant cast expr");
2005 case Instruction::Add: return MCBinaryExpr::createAdd(LHS, RHS, Ctx);
2006 case Instruction::Sub: return MCBinaryExpr::createSub(LHS, RHS, Ctx);
2007 case Instruction::Mul: return MCBinaryExpr::createMul(LHS, RHS, Ctx);
2008 case Instruction::SDiv: return MCBinaryExpr::createDiv(LHS, RHS, Ctx);
2009 case Instruction::SRem: return MCBinaryExpr::createMod(LHS, RHS, Ctx);
2010 case Instruction::Shl: return MCBinaryExpr::createShl(LHS, RHS, Ctx);
2011 case Instruction::And: return MCBinaryExpr::createAnd(LHS, RHS, Ctx);
2012 case Instruction::Or: return MCBinaryExpr::createOr (LHS, RHS, Ctx);
2013 case Instruction::Xor: return MCBinaryExpr::createXor(LHS, RHS, Ctx);
2019 static void emitGlobalConstantImpl(const DataLayout &DL, const Constant *C,
2021 const Constant *BaseCV = nullptr,
2022 uint64_t Offset = 0);
2024 static void emitGlobalConstantFP(const ConstantFP *CFP, AsmPrinter &AP);
2026 /// isRepeatedByteSequence - Determine whether the given value is
2027 /// composed of a repeated sequence of identical bytes and return the
2028 /// byte value. If it is not a repeated sequence, return -1.
2029 static int isRepeatedByteSequence(const ConstantDataSequential *V) {
2030 StringRef Data = V->getRawDataValues();
2031 assert(!Data.empty() && "Empty aggregates should be CAZ node");
2033 for (unsigned i = 1, e = Data.size(); i != e; ++i)
2034 if (Data[i] != C) return -1;
2035 return static_cast<uint8_t>(C); // Ensure 255 is not returned as -1.
2038 /// isRepeatedByteSequence - Determine whether the given value is
2039 /// composed of a repeated sequence of identical bytes and return the
2040 /// byte value. If it is not a repeated sequence, return -1.
2041 static int isRepeatedByteSequence(const Value *V, const DataLayout &DL) {
2042 if (const ConstantInt *CI = dyn_cast<ConstantInt>(V)) {
2043 uint64_t Size = DL.getTypeAllocSizeInBits(V->getType());
2044 assert(Size % 8 == 0);
2046 // Extend the element to take zero padding into account.
2047 APInt Value = CI->getValue().zextOrSelf(Size);
2048 if (!Value.isSplat(8))
2051 return Value.zextOrTrunc(8).getZExtValue();
2053 if (const ConstantArray *CA = dyn_cast<ConstantArray>(V)) {
2054 // Make sure all array elements are sequences of the same repeated
2056 assert(CA->getNumOperands() != 0 && "Should be a CAZ");
2057 Constant *Op0 = CA->getOperand(0);
2058 int Byte = isRepeatedByteSequence(Op0, DL);
2062 // All array elements must be equal.
2063 for (unsigned i = 1, e = CA->getNumOperands(); i != e; ++i)
2064 if (CA->getOperand(i) != Op0)
2069 if (const ConstantDataSequential *CDS = dyn_cast<ConstantDataSequential>(V))
2070 return isRepeatedByteSequence(CDS);
2075 static void emitGlobalConstantDataSequential(const DataLayout &DL,
2076 const ConstantDataSequential *CDS,
2078 // See if we can aggregate this into a .fill, if so, emit it as such.
2079 int Value = isRepeatedByteSequence(CDS, DL);
2081 uint64_t Bytes = DL.getTypeAllocSize(CDS->getType());
2082 // Don't emit a 1-byte object as a .fill.
2084 return AP.OutStreamer->emitFill(Bytes, Value);
2087 // If this can be emitted with .ascii/.asciz, emit it as such.
2088 if (CDS->isString())
2089 return AP.OutStreamer->EmitBytes(CDS->getAsString());
2091 // Otherwise, emit the values in successive locations.
2092 unsigned ElementByteSize = CDS->getElementByteSize();
2093 if (isa<IntegerType>(CDS->getElementType())) {
2094 for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i) {
2096 AP.OutStreamer->GetCommentOS() << format("0x%" PRIx64 "\n",
2097 CDS->getElementAsInteger(i));
2098 AP.OutStreamer->EmitIntValue(CDS->getElementAsInteger(i),
2102 for (unsigned I = 0, E = CDS->getNumElements(); I != E; ++I)
2103 emitGlobalConstantFP(cast<ConstantFP>(CDS->getElementAsConstant(I)), AP);
2106 unsigned Size = DL.getTypeAllocSize(CDS->getType());
2107 unsigned EmittedSize = DL.getTypeAllocSize(CDS->getType()->getElementType()) *
2108 CDS->getNumElements();
2109 if (unsigned Padding = Size - EmittedSize)
2110 AP.OutStreamer->EmitZeros(Padding);
2113 static void emitGlobalConstantArray(const DataLayout &DL,
2114 const ConstantArray *CA, AsmPrinter &AP,
2115 const Constant *BaseCV, uint64_t Offset) {
2116 // See if we can aggregate some values. Make sure it can be
2117 // represented as a series of bytes of the constant value.
2118 int Value = isRepeatedByteSequence(CA, DL);
2121 uint64_t Bytes = DL.getTypeAllocSize(CA->getType());
2122 AP.OutStreamer->emitFill(Bytes, Value);
2125 for (unsigned i = 0, e = CA->getNumOperands(); i != e; ++i) {
2126 emitGlobalConstantImpl(DL, CA->getOperand(i), AP, BaseCV, Offset);
2127 Offset += DL.getTypeAllocSize(CA->getOperand(i)->getType());
2132 static void emitGlobalConstantVector(const DataLayout &DL,
2133 const ConstantVector *CV, AsmPrinter &AP) {
2134 for (unsigned i = 0, e = CV->getType()->getNumElements(); i != e; ++i)
2135 emitGlobalConstantImpl(DL, CV->getOperand(i), AP);
2137 unsigned Size = DL.getTypeAllocSize(CV->getType());
2138 unsigned EmittedSize = DL.getTypeAllocSize(CV->getType()->getElementType()) *
2139 CV->getType()->getNumElements();
2140 if (unsigned Padding = Size - EmittedSize)
2141 AP.OutStreamer->EmitZeros(Padding);
2144 static void emitGlobalConstantStruct(const DataLayout &DL,
2145 const ConstantStruct *CS, AsmPrinter &AP,
2146 const Constant *BaseCV, uint64_t Offset) {
2147 // Print the fields in successive locations. Pad to align if needed!
2148 unsigned Size = DL.getTypeAllocSize(CS->getType());
2149 const StructLayout *Layout = DL.getStructLayout(CS->getType());
2150 uint64_t SizeSoFar = 0;
2151 for (unsigned i = 0, e = CS->getNumOperands(); i != e; ++i) {
2152 const Constant *Field = CS->getOperand(i);
2154 // Print the actual field value.
2155 emitGlobalConstantImpl(DL, Field, AP, BaseCV, Offset + SizeSoFar);
2157 // Check if padding is needed and insert one or more 0s.
2158 uint64_t FieldSize = DL.getTypeAllocSize(Field->getType());
2159 uint64_t PadSize = ((i == e-1 ? Size : Layout->getElementOffset(i+1))
2160 - Layout->getElementOffset(i)) - FieldSize;
2161 SizeSoFar += FieldSize + PadSize;
2163 // Insert padding - this may include padding to increase the size of the
2164 // current field up to the ABI size (if the struct is not packed) as well
2165 // as padding to ensure that the next field starts at the right offset.
2166 AP.OutStreamer->EmitZeros(PadSize);
2168 assert(SizeSoFar == Layout->getSizeInBytes() &&
2169 "Layout of constant struct may be incorrect!");
2172 static void emitGlobalConstantFP(const ConstantFP *CFP, AsmPrinter &AP) {
2173 APInt API = CFP->getValueAPF().bitcastToAPInt();
2175 // First print a comment with what we think the original floating-point value
2176 // should have been.
2177 if (AP.isVerbose()) {
2178 SmallString<8> StrVal;
2179 CFP->getValueAPF().toString(StrVal);
2182 CFP->getType()->print(AP.OutStreamer->GetCommentOS());
2184 AP.OutStreamer->GetCommentOS() << "Printing <null> Type";
2185 AP.OutStreamer->GetCommentOS() << ' ' << StrVal << '\n';
2188 // Now iterate through the APInt chunks, emitting them in endian-correct
2189 // order, possibly with a smaller chunk at beginning/end (e.g. for x87 80-bit
2191 unsigned NumBytes = API.getBitWidth() / 8;
2192 unsigned TrailingBytes = NumBytes % sizeof(uint64_t);
2193 const uint64_t *p = API.getRawData();
2195 // PPC's long double has odd notions of endianness compared to how LLVM
2196 // handles it: p[0] goes first for *big* endian on PPC.
2197 if (AP.getDataLayout().isBigEndian() && !CFP->getType()->isPPC_FP128Ty()) {
2198 int Chunk = API.getNumWords() - 1;
2201 AP.OutStreamer->EmitIntValue(p[Chunk--], TrailingBytes);
2203 for (; Chunk >= 0; --Chunk)
2204 AP.OutStreamer->EmitIntValue(p[Chunk], sizeof(uint64_t));
2207 for (Chunk = 0; Chunk < NumBytes / sizeof(uint64_t); ++Chunk)
2208 AP.OutStreamer->EmitIntValue(p[Chunk], sizeof(uint64_t));
2211 AP.OutStreamer->EmitIntValue(p[Chunk], TrailingBytes);
2214 // Emit the tail padding for the long double.
2215 const DataLayout &DL = AP.getDataLayout();
2216 AP.OutStreamer->EmitZeros(DL.getTypeAllocSize(CFP->getType()) -
2217 DL.getTypeStoreSize(CFP->getType()));
2220 static void emitGlobalConstantLargeInt(const ConstantInt *CI, AsmPrinter &AP) {
2221 const DataLayout &DL = AP.getDataLayout();
2222 unsigned BitWidth = CI->getBitWidth();
2224 // Copy the value as we may massage the layout for constants whose bit width
2225 // is not a multiple of 64-bits.
2226 APInt Realigned(CI->getValue());
2227 uint64_t ExtraBits = 0;
2228 unsigned ExtraBitsSize = BitWidth & 63;
2230 if (ExtraBitsSize) {
2231 // The bit width of the data is not a multiple of 64-bits.
2232 // The extra bits are expected to be at the end of the chunk of the memory.
2234 // * Nothing to be done, just record the extra bits to emit.
2236 // * Record the extra bits to emit.
2237 // * Realign the raw data to emit the chunks of 64-bits.
2238 if (DL.isBigEndian()) {
2239 // Basically the structure of the raw data is a chunk of 64-bits cells:
2240 // 0 1 BitWidth / 64
2241 // [chunk1][chunk2] ... [chunkN].
2242 // The most significant chunk is chunkN and it should be emitted first.
2243 // However, due to the alignment issue chunkN contains useless bits.
2244 // Realign the chunks so that they contain only useless information:
2245 // ExtraBits 0 1 (BitWidth / 64) - 1
2246 // chu[nk1 chu][nk2 chu] ... [nkN-1 chunkN]
2247 ExtraBits = Realigned.getRawData()[0] &
2248 (((uint64_t)-1) >> (64 - ExtraBitsSize));
2249 Realigned.lshrInPlace(ExtraBitsSize);
2251 ExtraBits = Realigned.getRawData()[BitWidth / 64];
2254 // We don't expect assemblers to support integer data directives
2255 // for more than 64 bits, so we emit the data in at most 64-bit
2256 // quantities at a time.
2257 const uint64_t *RawData = Realigned.getRawData();
2258 for (unsigned i = 0, e = BitWidth / 64; i != e; ++i) {
2259 uint64_t Val = DL.isBigEndian() ? RawData[e - i - 1] : RawData[i];
2260 AP.OutStreamer->EmitIntValue(Val, 8);
2263 if (ExtraBitsSize) {
2264 // Emit the extra bits after the 64-bits chunks.
2266 // Emit a directive that fills the expected size.
2267 uint64_t Size = AP.getDataLayout().getTypeAllocSize(CI->getType());
2268 Size -= (BitWidth / 64) * 8;
2269 assert(Size && Size * 8 >= ExtraBitsSize &&
2270 (ExtraBits & (((uint64_t)-1) >> (64 - ExtraBitsSize)))
2271 == ExtraBits && "Directive too small for extra bits.");
2272 AP.OutStreamer->EmitIntValue(ExtraBits, Size);
2276 /// \brief Transform a not absolute MCExpr containing a reference to a GOT
2277 /// equivalent global, by a target specific GOT pc relative access to the
2279 static void handleIndirectSymViaGOTPCRel(AsmPrinter &AP, const MCExpr **ME,
2280 const Constant *BaseCst,
2282 // The global @foo below illustrates a global that uses a got equivalent.
2284 // @bar = global i32 42
2285 // @gotequiv = private unnamed_addr constant i32* @bar
2286 // @foo = i32 trunc (i64 sub (i64 ptrtoint (i32** @gotequiv to i64),
2287 // i64 ptrtoint (i32* @foo to i64))
2290 // The cstexpr in @foo is converted into the MCExpr `ME`, where we actually
2291 // check whether @foo is suitable to use a GOTPCREL. `ME` is usually in the
2294 // foo = cstexpr, where
2295 // cstexpr := <gotequiv> - "." + <cst>
2296 // cstexpr := <gotequiv> - (<foo> - <offset from @foo base>) + <cst>
2298 // After canonicalization by evaluateAsRelocatable `ME` turns into:
2300 // cstexpr := <gotequiv> - <foo> + gotpcrelcst, where
2301 // gotpcrelcst := <offset from @foo base> + <cst>
2304 if (!(*ME)->evaluateAsRelocatable(MV, nullptr, nullptr) || MV.isAbsolute())
2306 const MCSymbolRefExpr *SymA = MV.getSymA();
2310 // Check that GOT equivalent symbol is cached.
2311 const MCSymbol *GOTEquivSym = &SymA->getSymbol();
2312 if (!AP.GlobalGOTEquivs.count(GOTEquivSym))
2315 const GlobalValue *BaseGV = dyn_cast_or_null<GlobalValue>(BaseCst);
2319 // Check for a valid base symbol
2320 const MCSymbol *BaseSym = AP.getSymbol(BaseGV);
2321 const MCSymbolRefExpr *SymB = MV.getSymB();
2323 if (!SymB || BaseSym != &SymB->getSymbol())
2326 // Make sure to match:
2328 // gotpcrelcst := <offset from @foo base> + <cst>
2330 // If gotpcrelcst is positive it means that we can safely fold the pc rel
2331 // displacement into the GOTPCREL. We can also can have an extra offset <cst>
2332 // if the target knows how to encode it.
2334 int64_t GOTPCRelCst = Offset + MV.getConstant();
2335 if (GOTPCRelCst < 0)
2337 if (!AP.getObjFileLowering().supportGOTPCRelWithOffset() && GOTPCRelCst != 0)
2340 // Emit the GOT PC relative to replace the got equivalent global, i.e.:
2347 // .long gotequiv - "." + <cst>
2349 // is replaced by the target specific equivalent to:
2354 // .long bar@GOTPCREL+<gotpcrelcst>
2356 AsmPrinter::GOTEquivUsePair Result = AP.GlobalGOTEquivs[GOTEquivSym];
2357 const GlobalVariable *GV = Result.first;
2358 int NumUses = (int)Result.second;
2359 const GlobalValue *FinalGV = dyn_cast<GlobalValue>(GV->getOperand(0));
2360 const MCSymbol *FinalSym = AP.getSymbol(FinalGV);
2361 *ME = AP.getObjFileLowering().getIndirectSymViaGOTPCRel(
2362 FinalSym, MV, Offset, AP.MMI, *AP.OutStreamer);
2364 // Update GOT equivalent usage information
2367 AP.GlobalGOTEquivs[GOTEquivSym] = std::make_pair(GV, NumUses);
2370 static void emitGlobalConstantImpl(const DataLayout &DL, const Constant *CV,
2371 AsmPrinter &AP, const Constant *BaseCV,
2373 uint64_t Size = DL.getTypeAllocSize(CV->getType());
2375 // Globals with sub-elements such as combinations of arrays and structs
2376 // are handled recursively by emitGlobalConstantImpl. Keep track of the
2377 // constant symbol base and the current position with BaseCV and Offset.
2378 if (!BaseCV && CV->hasOneUse())
2379 BaseCV = dyn_cast<Constant>(CV->user_back());
2381 if (isa<ConstantAggregateZero>(CV) || isa<UndefValue>(CV))
2382 return AP.OutStreamer->EmitZeros(Size);
2384 if (const ConstantInt *CI = dyn_cast<ConstantInt>(CV)) {
2391 AP.OutStreamer->GetCommentOS() << format("0x%" PRIx64 "\n",
2392 CI->getZExtValue());
2393 AP.OutStreamer->EmitIntValue(CI->getZExtValue(), Size);
2396 emitGlobalConstantLargeInt(CI, AP);
2401 if (const ConstantFP *CFP = dyn_cast<ConstantFP>(CV))
2402 return emitGlobalConstantFP(CFP, AP);
2404 if (isa<ConstantPointerNull>(CV)) {
2405 AP.OutStreamer->EmitIntValue(0, Size);
2409 if (const ConstantDataSequential *CDS = dyn_cast<ConstantDataSequential>(CV))
2410 return emitGlobalConstantDataSequential(DL, CDS, AP);
2412 if (const ConstantArray *CVA = dyn_cast<ConstantArray>(CV))
2413 return emitGlobalConstantArray(DL, CVA, AP, BaseCV, Offset);
2415 if (const ConstantStruct *CVS = dyn_cast<ConstantStruct>(CV))
2416 return emitGlobalConstantStruct(DL, CVS, AP, BaseCV, Offset);
2418 if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(CV)) {
2419 // Look through bitcasts, which might not be able to be MCExpr'ized (e.g. of
2421 if (CE->getOpcode() == Instruction::BitCast)
2422 return emitGlobalConstantImpl(DL, CE->getOperand(0), AP);
2425 // If the constant expression's size is greater than 64-bits, then we have
2426 // to emit the value in chunks. Try to constant fold the value and emit it
2428 Constant *New = ConstantFoldConstant(CE, DL);
2429 if (New && New != CE)
2430 return emitGlobalConstantImpl(DL, New, AP);
2434 if (const ConstantVector *V = dyn_cast<ConstantVector>(CV))
2435 return emitGlobalConstantVector(DL, V, AP);
2437 // Otherwise, it must be a ConstantExpr. Lower it to an MCExpr, then emit it
2438 // thread the streamer with EmitValue.
2439 const MCExpr *ME = AP.lowerConstant(CV);
2441 // Since lowerConstant already folded and got rid of all IR pointer and
2442 // integer casts, detect GOT equivalent accesses by looking into the MCExpr
2444 if (AP.getObjFileLowering().supportIndirectSymViaGOTPCRel())
2445 handleIndirectSymViaGOTPCRel(AP, &ME, BaseCV, Offset);
2447 AP.OutStreamer->EmitValue(ME, Size);
2450 /// EmitGlobalConstant - Print a general LLVM constant to the .s file.
2451 void AsmPrinter::EmitGlobalConstant(const DataLayout &DL, const Constant *CV) {
2452 uint64_t Size = DL.getTypeAllocSize(CV->getType());
2454 emitGlobalConstantImpl(DL, CV, *this);
2455 else if (MAI->hasSubsectionsViaSymbols()) {
2456 // If the global has zero size, emit a single byte so that two labels don't
2457 // look like they are at the same location.
2458 OutStreamer->EmitIntValue(0, 1);
2462 void AsmPrinter::EmitMachineConstantPoolValue(MachineConstantPoolValue *MCPV) {
2463 // Target doesn't support this yet!
2464 llvm_unreachable("Target does not support EmitMachineConstantPoolValue");
2467 void AsmPrinter::printOffset(int64_t Offset, raw_ostream &OS) const {
2469 OS << '+' << Offset;
2470 else if (Offset < 0)
2474 //===----------------------------------------------------------------------===//
2475 // Symbol Lowering Routines.
2476 //===----------------------------------------------------------------------===//
2478 MCSymbol *AsmPrinter::createTempSymbol(const Twine &Name) const {
2479 return OutContext.createTempSymbol(Name, true);
2482 MCSymbol *AsmPrinter::GetBlockAddressSymbol(const BlockAddress *BA) const {
2483 return MMI->getAddrLabelSymbol(BA->getBasicBlock());
2486 MCSymbol *AsmPrinter::GetBlockAddressSymbol(const BasicBlock *BB) const {
2487 return MMI->getAddrLabelSymbol(BB);
2490 /// GetCPISymbol - Return the symbol for the specified constant pool entry.
2491 MCSymbol *AsmPrinter::GetCPISymbol(unsigned CPID) const {
2492 const DataLayout &DL = getDataLayout();
2493 return OutContext.getOrCreateSymbol(Twine(DL.getPrivateGlobalPrefix()) +
2494 "CPI" + Twine(getFunctionNumber()) + "_" +
2498 /// GetJTISymbol - Return the symbol for the specified jump table entry.
2499 MCSymbol *AsmPrinter::GetJTISymbol(unsigned JTID, bool isLinkerPrivate) const {
2500 return MF->getJTISymbol(JTID, OutContext, isLinkerPrivate);
2503 /// GetJTSetSymbol - Return the symbol for the specified jump table .set
2504 /// FIXME: privatize to AsmPrinter.
2505 MCSymbol *AsmPrinter::GetJTSetSymbol(unsigned UID, unsigned MBBID) const {
2506 const DataLayout &DL = getDataLayout();
2507 return OutContext.getOrCreateSymbol(Twine(DL.getPrivateGlobalPrefix()) +
2508 Twine(getFunctionNumber()) + "_" +
2509 Twine(UID) + "_set_" + Twine(MBBID));
2512 MCSymbol *AsmPrinter::getSymbolWithGlobalValueBase(const GlobalValue *GV,
2513 StringRef Suffix) const {
2514 return getObjFileLowering().getSymbolWithGlobalValueBase(GV, Suffix, TM);
2517 /// Return the MCSymbol for the specified ExternalSymbol.
2518 MCSymbol *AsmPrinter::GetExternalSymbolSymbol(StringRef Sym) const {
2519 SmallString<60> NameStr;
2520 Mangler::getNameWithPrefix(NameStr, Sym, getDataLayout());
2521 return OutContext.getOrCreateSymbol(NameStr);
2524 /// PrintParentLoopComment - Print comments about parent loops of this one.
2525 static void PrintParentLoopComment(raw_ostream &OS, const MachineLoop *Loop,
2526 unsigned FunctionNumber) {
2528 PrintParentLoopComment(OS, Loop->getParentLoop(), FunctionNumber);
2529 OS.indent(Loop->getLoopDepth()*2)
2530 << "Parent Loop BB" << FunctionNumber << "_"
2531 << Loop->getHeader()->getNumber()
2532 << " Depth=" << Loop->getLoopDepth() << '\n';
2536 /// PrintChildLoopComment - Print comments about child loops within
2537 /// the loop for this basic block, with nesting.
2538 static void PrintChildLoopComment(raw_ostream &OS, const MachineLoop *Loop,
2539 unsigned FunctionNumber) {
2540 // Add child loop information
2541 for (const MachineLoop *CL : *Loop) {
2542 OS.indent(CL->getLoopDepth()*2)
2543 << "Child Loop BB" << FunctionNumber << "_"
2544 << CL->getHeader()->getNumber() << " Depth " << CL->getLoopDepth()
2546 PrintChildLoopComment(OS, CL, FunctionNumber);
2550 /// emitBasicBlockLoopComments - Pretty-print comments for basic blocks.
2551 static void emitBasicBlockLoopComments(const MachineBasicBlock &MBB,
2552 const MachineLoopInfo *LI,
2553 const AsmPrinter &AP) {
2554 // Add loop depth information
2555 const MachineLoop *Loop = LI->getLoopFor(&MBB);
2558 MachineBasicBlock *Header = Loop->getHeader();
2559 assert(Header && "No header for loop");
2561 // If this block is not a loop header, just print out what is the loop header
2563 if (Header != &MBB) {
2564 AP.OutStreamer->AddComment(" in Loop: Header=BB" +
2565 Twine(AP.getFunctionNumber())+"_" +
2566 Twine(Loop->getHeader()->getNumber())+
2567 " Depth="+Twine(Loop->getLoopDepth()));
2571 // Otherwise, it is a loop header. Print out information about child and
2573 raw_ostream &OS = AP.OutStreamer->GetCommentOS();
2575 PrintParentLoopComment(OS, Loop->getParentLoop(), AP.getFunctionNumber());
2578 OS.indent(Loop->getLoopDepth()*2-2);
2583 OS << "Loop Header: Depth=" + Twine(Loop->getLoopDepth()) << '\n';
2585 PrintChildLoopComment(OS, Loop, AP.getFunctionNumber());
2588 /// EmitBasicBlockStart - This method prints the label for the specified
2589 /// MachineBasicBlock, an alignment (if present) and a comment describing
2590 /// it if appropriate.
2591 void AsmPrinter::EmitBasicBlockStart(const MachineBasicBlock &MBB) const {
2592 // End the previous funclet and start a new one.
2593 if (MBB.isEHFuncletEntry()) {
2594 for (const HandlerInfo &HI : Handlers) {
2595 HI.Handler->endFunclet();
2596 HI.Handler->beginFunclet(MBB);
2600 // Emit an alignment directive for this block, if needed.
2601 if (unsigned Align = MBB.getAlignment())
2602 EmitAlignment(Align);
2604 // If the block has its address taken, emit any labels that were used to
2605 // reference the block. It is possible that there is more than one label
2606 // here, because multiple LLVM BB's may have been RAUW'd to this block after
2607 // the references were generated.
2608 if (MBB.hasAddressTaken()) {
2609 const BasicBlock *BB = MBB.getBasicBlock();
2611 OutStreamer->AddComment("Block address taken");
2613 // MBBs can have their address taken as part of CodeGen without having
2614 // their corresponding BB's address taken in IR
2615 if (BB->hasAddressTaken())
2616 for (MCSymbol *Sym : MMI->getAddrLabelSymbolToEmit(BB))
2617 OutStreamer->EmitLabel(Sym);
2620 // Print some verbose block comments.
2622 if (const BasicBlock *BB = MBB.getBasicBlock()) {
2623 if (BB->hasName()) {
2624 BB->printAsOperand(OutStreamer->GetCommentOS(),
2625 /*PrintType=*/false, BB->getModule());
2626 OutStreamer->GetCommentOS() << '\n';
2629 emitBasicBlockLoopComments(MBB, LI, *this);
2632 // Print the main label for the block.
2633 if (MBB.pred_empty() ||
2634 (isBlockOnlyReachableByFallthrough(&MBB) && !MBB.isEHFuncletEntry())) {
2636 // NOTE: Want this comment at start of line, don't emit with AddComment.
2637 OutStreamer->emitRawComment(" BB#" + Twine(MBB.getNumber()) + ":", false);
2640 OutStreamer->EmitLabel(MBB.getSymbol());
2644 void AsmPrinter::EmitVisibility(MCSymbol *Sym, unsigned Visibility,
2645 bool IsDefinition) const {
2646 MCSymbolAttr Attr = MCSA_Invalid;
2648 switch (Visibility) {
2650 case GlobalValue::HiddenVisibility:
2652 Attr = MAI->getHiddenVisibilityAttr();
2654 Attr = MAI->getHiddenDeclarationVisibilityAttr();
2656 case GlobalValue::ProtectedVisibility:
2657 Attr = MAI->getProtectedVisibilityAttr();
2661 if (Attr != MCSA_Invalid)
2662 OutStreamer->EmitSymbolAttribute(Sym, Attr);
2665 /// isBlockOnlyReachableByFallthough - Return true if the basic block has
2666 /// exactly one predecessor and the control transfer mechanism between
2667 /// the predecessor and this block is a fall-through.
2669 isBlockOnlyReachableByFallthrough(const MachineBasicBlock *MBB) const {
2670 // If this is a landing pad, it isn't a fall through. If it has no preds,
2671 // then nothing falls through to it.
2672 if (MBB->isEHPad() || MBB->pred_empty())
2675 // If there isn't exactly one predecessor, it can't be a fall through.
2676 if (MBB->pred_size() > 1)
2679 // The predecessor has to be immediately before this block.
2680 MachineBasicBlock *Pred = *MBB->pred_begin();
2681 if (!Pred->isLayoutSuccessor(MBB))
2684 // If the block is completely empty, then it definitely does fall through.
2688 // Check the terminators in the previous blocks
2689 for (const auto &MI : Pred->terminators()) {
2690 // If it is not a simple branch, we are in a table somewhere.
2691 if (!MI.isBranch() || MI.isIndirectBranch())
2694 // If we are the operands of one of the branches, this is not a fall
2695 // through. Note that targets with delay slots will usually bundle
2696 // terminators with the delay slot instruction.
2697 for (ConstMIBundleOperands OP(MI); OP.isValid(); ++OP) {
2700 if (OP->isMBB() && OP->getMBB() == MBB)
2708 GCMetadataPrinter *AsmPrinter::GetOrCreateGCPrinter(GCStrategy &S) {
2709 if (!S.usesMetadata())
2712 assert(!S.useStatepoints() && "statepoints do not currently support custom"
2713 " stackmap formats, please see the documentation for a description of"
2714 " the default format. If you really need a custom serialized format,"
2715 " please file a bug");
2717 gcp_map_type &GCMap = getGCMap(GCMetadataPrinters);
2718 gcp_map_type::iterator GCPI = GCMap.find(&S);
2719 if (GCPI != GCMap.end())
2720 return GCPI->second.get();
2722 auto Name = S.getName();
2724 for (GCMetadataPrinterRegistry::iterator
2725 I = GCMetadataPrinterRegistry::begin(),
2726 E = GCMetadataPrinterRegistry::end(); I != E; ++I)
2727 if (Name == I->getName()) {
2728 std::unique_ptr<GCMetadataPrinter> GMP = I->instantiate();
2730 auto IterBool = GCMap.insert(std::make_pair(&S, std::move(GMP)));
2731 return IterBool.first->second.get();
2734 report_fatal_error("no GCMetadataPrinter registered for GC: " + Twine(Name));
2737 /// Pin vtable to this file.
2738 AsmPrinterHandler::~AsmPrinterHandler() = default;
2740 void AsmPrinterHandler::markFunctionEnd() {}
2742 // In the binary's "xray_instr_map" section, an array of these function entries
2743 // describes each instrumentation point. When XRay patches your code, the index
2744 // into this table will be given to your handler as a patch point identifier.
2745 void AsmPrinter::XRayFunctionEntry::emit(int Bytes, MCStreamer *Out,
2746 const MCSymbol *CurrentFnSym) const {
2747 Out->EmitSymbolValue(Sled, Bytes);
2748 Out->EmitSymbolValue(CurrentFnSym, Bytes);
2749 auto Kind8 = static_cast<uint8_t>(Kind);
2750 Out->EmitBytes(StringRef(reinterpret_cast<const char *>(&Kind8), 1));
2752 StringRef(reinterpret_cast<const char *>(&AlwaysInstrument), 1));
2753 Out->EmitZeros(2 * Bytes - 2); // Pad the previous two entries
2756 void AsmPrinter::emitXRayTable() {
2760 auto PrevSection = OutStreamer->getCurrentSectionOnly();
2761 auto Fn = MF->getFunction();
2762 MCSection *Section = nullptr;
2763 if (MF->getSubtarget().getTargetTriple().isOSBinFormatELF()) {
2764 if (Fn->hasComdat()) {
2765 Section = OutContext.getELFSection("xray_instr_map", ELF::SHT_PROGBITS,
2766 ELF::SHF_ALLOC | ELF::SHF_GROUP, 0,
2767 Fn->getComdat()->getName());
2769 Section = OutContext.getELFSection("xray_instr_map", ELF::SHT_PROGBITS,
2772 } else if (MF->getSubtarget().getTargetTriple().isOSBinFormatMachO()) {
2773 Section = OutContext.getMachOSection("__DATA", "xray_instr_map", 0,
2774 SectionKind::getReadOnlyWithRel());
2776 llvm_unreachable("Unsupported target");
2779 // Before we switch over, we force a reference to a label inside the
2780 // xray_instr_map section. Since this function is always called just
2781 // before the function's end, we assume that this is happening after
2782 // the last return instruction.
2784 auto WordSizeBytes = MAI->getCodePointerSize();
2785 MCSymbol *Tmp = OutContext.createTempSymbol("xray_synthetic_", true);
2786 OutStreamer->EmitCodeAlignment(16);
2787 OutStreamer->EmitSymbolValue(Tmp, WordSizeBytes, false);
2788 OutStreamer->SwitchSection(Section);
2789 OutStreamer->EmitLabel(Tmp);
2790 for (const auto &Sled : Sleds)
2791 Sled.emit(WordSizeBytes, OutStreamer.get(), CurrentFnSym);
2793 OutStreamer->SwitchSection(PrevSection);
2797 void AsmPrinter::recordSled(MCSymbol *Sled, const MachineInstr &MI,
2799 auto Fn = MI.getParent()->getParent()->getFunction();
2800 auto Attr = Fn->getFnAttribute("function-instrument");
2801 bool LogArgs = Fn->hasFnAttribute("xray-log-args");
2802 bool AlwaysInstrument =
2803 Attr.isStringAttribute() && Attr.getValueAsString() == "xray-always";
2804 if (Kind == SledKind::FUNCTION_ENTER && LogArgs)
2805 Kind = SledKind::LOG_ARGS_ENTER;
2807 XRayFunctionEntry{ Sled, CurrentFnSym, Kind, AlwaysInstrument, Fn });
2810 uint16_t AsmPrinter::getDwarfVersion() const {
2811 return OutStreamer->getContext().getDwarfVersion();
2814 void AsmPrinter::setDwarfVersion(uint16_t Version) {
2815 OutStreamer->getContext().setDwarfVersion(Version);