1 //===-- AsmPrinter.cpp - Common AsmPrinter code ---------------------------===//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // This file implements the AsmPrinter class.
11 //
12 //===----------------------------------------------------------------------===//
14 #define DEBUG_TYPE "asm-printer"
15 #include "llvm/CodeGen/AsmPrinter.h"
16 #include "DwarfDebug.h"
17 #include "DwarfException.h"
18 #include "llvm/ADT/SmallString.h"
19 #include "llvm/ADT/Statistic.h"
20 #include "llvm/Analysis/ConstantFolding.h"
21 #include "llvm/CodeGen/GCMetadataPrinter.h"
22 #include "llvm/CodeGen/MachineConstantPool.h"
23 #include "llvm/CodeGen/MachineFrameInfo.h"
24 #include "llvm/CodeGen/MachineFunction.h"
25 #include "llvm/CodeGen/MachineInstrBundle.h"
26 #include "llvm/CodeGen/MachineJumpTableInfo.h"
27 #include "llvm/CodeGen/MachineLoopInfo.h"
28 #include "llvm/CodeGen/MachineModuleInfo.h"
29 #include "llvm/DebugInfo.h"
30 #include "llvm/IR/DataLayout.h"
31 #include "llvm/IR/Mangler.h"
32 #include "llvm/IR/Module.h"
33 #include "llvm/IR/Operator.h"
34 #include "llvm/MC/MCAsmInfo.h"
35 #include "llvm/MC/MCContext.h"
36 #include "llvm/MC/MCExpr.h"
37 #include "llvm/MC/MCInst.h"
38 #include "llvm/MC/MCSection.h"
39 #include "llvm/MC/MCStreamer.h"
40 #include "llvm/MC/MCSymbol.h"
41 #include "llvm/Support/ErrorHandling.h"
42 #include "llvm/Support/Format.h"
43 #include "llvm/Support/MathExtras.h"
44 #include "llvm/Support/Timer.h"
45 #include "llvm/Target/TargetFrameLowering.h"
46 #include "llvm/Target/TargetInstrInfo.h"
47 #include "llvm/Target/TargetLowering.h"
48 #include "llvm/Target/TargetLoweringObjectFile.h"
49 #include "llvm/Target/TargetOptions.h"
50 #include "llvm/Target/TargetRegisterInfo.h"
51 #include "llvm/Target/TargetSubtargetInfo.h"
52 #include "llvm/Transforms/Utils/GlobalStatus.h"
53 #include "WinCodeViewLineTables.h"
54 using namespace llvm;
56 static const char *const DWARFGroupName = "DWARF Emission";
57 static const char *const DbgTimerName = "Debug Info Emission";
58 static const char *const EHTimerName = "DWARF Exception Writer";
59 static const char *const CodeViewLineTablesGroupName = "CodeView Line Tables";
61 STATISTIC(EmittedInsts, "Number of machine instrs printed");
63 char AsmPrinter::ID = 0;
65 typedef DenseMap<GCStrategy*,GCMetadataPrinter*> gcp_map_type;
66 static gcp_map_type &getGCMap(void *&P) {
67 if (P == 0)
68 P = new gcp_map_type();
69 return *(gcp_map_type*)P;
70 }
73 /// getGVAlignmentLog2 - Return the alignment to use for the specified global
74 /// value in log2 form. This rounds up to the preferred alignment if possible
75 /// and legal.
76 static unsigned getGVAlignmentLog2(const GlobalValue *GV, const DataLayout &TD,
77 unsigned InBits = 0) {
78 unsigned NumBits = 0;
79 if (const GlobalVariable *GVar = dyn_cast<GlobalVariable>(GV))
80 NumBits = TD.getPreferredAlignmentLog(GVar);
82 // If InBits is specified, round it to it.
83 if (InBits > NumBits)
84 NumBits = InBits;
86 // If the GV has a specified alignment, take it into account.
87 if (GV->getAlignment() == 0)
88 return NumBits;
90 unsigned GVAlign = Log2_32(GV->getAlignment());
92 // If the GVAlign is larger than NumBits, or if we are required to obey
93 // NumBits because the GV has an assigned section, obey it.
94 if (GVAlign > NumBits || GV->hasSection())
95 NumBits = GVAlign;
96 return NumBits;
97 }
99 AsmPrinter::AsmPrinter(TargetMachine &tm, MCStreamer &Streamer)
100 : MachineFunctionPass(ID),
101 TM(tm), MAI(tm.getMCAsmInfo()), MII(tm.getInstrInfo()),
102 OutContext(Streamer.getContext()),
103 OutStreamer(Streamer),
104 LastMI(0), LastFn(0), Counter(~0U), SetCounter(0) {
105 DD = 0; MMI = 0; LI = 0; MF = 0;
106 CurrentFnSym = CurrentFnSymForSize = 0;
107 GCMetadataPrinters = 0;
108 VerboseAsm = Streamer.isVerboseAsm();
109 }
111 AsmPrinter::~AsmPrinter() {
112 assert(DD == 0 && Handlers.empty() && "Debug/EH info didn't get finalized");
114 if (GCMetadataPrinters != 0) {
115 gcp_map_type &GCMap = getGCMap(GCMetadataPrinters);
117 for (gcp_map_type::iterator I = GCMap.begin(), E = GCMap.end(); I != E; ++I)
118 delete I->second;
119 delete &GCMap;
120 GCMetadataPrinters = 0;
121 }
123 delete &OutStreamer;
124 }
126 /// getFunctionNumber - Return a unique ID for the current function.
127 ///
128 unsigned AsmPrinter::getFunctionNumber() const {
129 return MF->getFunctionNumber();
130 }
132 const TargetLoweringObjectFile &AsmPrinter::getObjFileLowering() const {
133 return TM.getTargetLowering()->getObjFileLowering();
134 }
136 /// getDataLayout - Return information about data layout.
137 const DataLayout &AsmPrinter::getDataLayout() const {
138 return *TM.getDataLayout();
139 }
141 const MCSubtargetInfo &AsmPrinter::getSubtargetInfo() const {
142 return TM.getSubtarget<MCSubtargetInfo>();
143 }
145 void AsmPrinter::EmitToStreamer(MCStreamer &S, const MCInst &Inst) {
146 S.EmitInstruction(Inst, getSubtargetInfo());
147 }
149 StringRef AsmPrinter::getTargetTriple() const {
150 return TM.getTargetTriple();
151 }
153 /// getCurrentSection() - Return the current section we are emitting to.
154 const MCSection *AsmPrinter::getCurrentSection() const {
155 return OutStreamer.getCurrentSection().first;
156 }
160 void AsmPrinter::getAnalysisUsage(AnalysisUsage &AU) const {
161 AU.setPreservesAll();
162 MachineFunctionPass::getAnalysisUsage(AU);
163 AU.addRequired<MachineModuleInfo>();
164 AU.addRequired<GCModuleInfo>();
165 if (isVerbose())
166 AU.addRequired<MachineLoopInfo>();
167 }
169 bool AsmPrinter::doInitialization(Module &M) {
170 MMI = getAnalysisIfAvailable<MachineModuleInfo>();
171 MMI->AnalyzeModule(M);
173 // Initialize TargetLoweringObjectFile.
174 const_cast<TargetLoweringObjectFile&>(getObjFileLowering())
175 .Initialize(OutContext, TM);
177 OutStreamer.InitSections(false);
179 Mang = new Mangler(TM.getDataLayout());
181 // Allow the target to emit any magic that it wants at the start of the file.
182 EmitStartOfAsmFile(M);
184 // Very minimal debug info. It is ignored if we emit actual debug info. If we
185 // don't, this at least helps the user find where a global came from.
186 if (MAI->hasSingleParameterDotFile()) {
187 // .file "foo.c"
188 OutStreamer.EmitFileDirective(M.getModuleIdentifier());
189 }
191 GCModuleInfo *MI = getAnalysisIfAvailable<GCModuleInfo>();
192 assert(MI && "AsmPrinter didn't require GCModuleInfo?");
193 for (GCModuleInfo::iterator I = MI->begin(), E = MI->end(); I != E; ++I)
194 if (GCMetadataPrinter *MP = GetOrCreateGCPrinter(*I))
195 MP->beginAssembly(*this);
197 // Emit module-level inline asm if it exists.
198 if (!M.getModuleInlineAsm().empty()) {
199 OutStreamer.AddComment("Start of file scope inline assembly");
200 OutStreamer.AddBlankLine();
201 EmitInlineAsm(M.getModuleInlineAsm()+"\n");
202 OutStreamer.AddComment("End of file scope inline assembly");
203 OutStreamer.AddBlankLine();
204 }
206 if (MAI->doesSupportDebugInformation()) {
207 if (Triple(TM.getTargetTriple()).getOS() == Triple::Win32) {
208 Handlers.push_back(HandlerInfo(new WinCodeViewLineTables(this),
209 DbgTimerName,
210 CodeViewLineTablesGroupName));
211 } else {
212 DD = new DwarfDebug(this, &M);
213 Handlers.push_back(HandlerInfo(DD, DbgTimerName, DWARFGroupName));
214 }
215 }
217 DwarfException *DE = 0;
218 switch (MAI->getExceptionHandlingType()) {
219 case ExceptionHandling::None:
220 break;
221 case ExceptionHandling::SjLj:
222 case ExceptionHandling::DwarfCFI:
223 DE = new DwarfCFIException(this);
224 break;
225 case ExceptionHandling::ARM:
226 DE = new ARMException(this);
227 break;
228 case ExceptionHandling::Win64:
229 DE = new Win64Exception(this);
230 break;
231 }
232 if (DE)
233 Handlers.push_back(HandlerInfo(DE, EHTimerName, DWARFGroupName));
234 return false;
235 }
237 static bool canBeHidden(const GlobalValue *GV, const MCAsmInfo &MAI) {
238 GlobalValue::LinkageTypes Linkage = GV->getLinkage();
239 if (Linkage != GlobalValue::LinkOnceODRLinkage)
240 return false;
242 if (!MAI.hasWeakDefCanBeHiddenDirective())
243 return false;
245 if (GV->hasUnnamedAddr())
246 return true;
248 // This is only used for MachO, so right now it doesn't really matter how
249 // we handle alias. Revisit this once the MachO linker implements aliases.
250 if (isa<GlobalAlias>(GV))
251 return false;
253 // If it is a non constant variable, it needs to be uniqued across shared
254 // objects.
255 if (const GlobalVariable *Var = dyn_cast<GlobalVariable>(GV)) {
256 if (!Var->isConstant())
257 return false;
258 }
260 GlobalStatus GS;
261 if (!GlobalStatus::analyzeGlobal(GV, GS) && !GS.IsCompared)
262 return true;
264 return false;
265 }
267 void AsmPrinter::EmitLinkage(const GlobalValue *GV, MCSymbol *GVSym) const {
268 GlobalValue::LinkageTypes Linkage = GV->getLinkage();
269 switch (Linkage) {
270 case GlobalValue::CommonLinkage:
271 case GlobalValue::LinkOnceAnyLinkage:
272 case GlobalValue::LinkOnceODRLinkage:
273 case GlobalValue::WeakAnyLinkage:
274 case GlobalValue::WeakODRLinkage:
275 case GlobalValue::LinkerPrivateWeakLinkage:
276 if (MAI->hasWeakDefDirective()) {
277 // .globl _foo
278 OutStreamer.EmitSymbolAttribute(GVSym, MCSA_Global);
280 if (!canBeHidden(GV, *MAI))
281 // .weak_definition _foo
282 OutStreamer.EmitSymbolAttribute(GVSym, MCSA_WeakDefinition);
283 else
284 OutStreamer.EmitSymbolAttribute(GVSym, MCSA_WeakDefAutoPrivate);
285 } else if (MAI->hasLinkOnceDirective()) {
286 // .globl _foo
287 OutStreamer.EmitSymbolAttribute(GVSym, MCSA_Global);
288 //NOTE: linkonce is handled by the section the symbol was assigned to.
289 } else {
290 // .weak _foo
291 OutStreamer.EmitSymbolAttribute(GVSym, MCSA_Weak);
292 }
293 return;
294 case GlobalValue::AppendingLinkage:
295 // FIXME: appending linkage variables should go into a section of
296 // their name or something. For now, just emit them as external.
297 case GlobalValue::ExternalLinkage:
298 // If external or appending, declare as a global symbol.
299 // .globl _foo
300 OutStreamer.EmitSymbolAttribute(GVSym, MCSA_Global);
301 return;
302 case GlobalValue::PrivateLinkage:
303 case GlobalValue::InternalLinkage:
304 case GlobalValue::LinkerPrivateLinkage:
305 return;
306 case GlobalValue::AvailableExternallyLinkage:
307 llvm_unreachable("Should never emit this");
308 case GlobalValue::ExternalWeakLinkage:
309 llvm_unreachable("Don't know how to emit these");
310 }
311 llvm_unreachable("Unknown linkage type!");
312 }
314 void AsmPrinter::getNameWithPrefix(SmallVectorImpl<char> &Name,
315 const GlobalValue *GV) const {
316 TM.getNameWithPrefix(Name, GV, *Mang);
317 }
319 MCSymbol *AsmPrinter::getSymbol(const GlobalValue *GV) const {
320 return TM.getSymbol(GV, *Mang);
321 }
323 /// EmitGlobalVariable - Emit the specified global variable to the .s file.
324 void AsmPrinter::EmitGlobalVariable(const GlobalVariable *GV) {
325 if (GV->hasInitializer()) {
326 // Check to see if this is a special global used by LLVM, if so, emit it.
327 if (EmitSpecialLLVMGlobal(GV))
328 return;
330 if (isVerbose()) {
331 GV->printAsOperand(OutStreamer.GetCommentOS(),
332 /*PrintType=*/false, GV->getParent());
333 OutStreamer.GetCommentOS() << '\n';
334 }
335 }
337 MCSymbol *GVSym = getSymbol(GV);
338 EmitVisibility(GVSym, GV->getVisibility(), !GV->isDeclaration());
340 if (!GV->hasInitializer()) // External globals require no extra code.
341 return;
343 if (MAI->hasDotTypeDotSizeDirective())
344 OutStreamer.EmitSymbolAttribute(GVSym, MCSA_ELF_TypeObject);
346 SectionKind GVKind = TargetLoweringObjectFile::getKindForGlobal(GV, TM);
348 const DataLayout *DL = TM.getDataLayout();
349 uint64_t Size = DL->getTypeAllocSize(GV->getType()->getElementType());
351 // If the alignment is specified, we *must* obey it. Overaligning a global
352 // with a specified alignment is a prompt way to break globals emitted to
353 // sections and expected to be contiguous (e.g. ObjC metadata).
354 unsigned AlignLog = getGVAlignmentLog2(GV, *DL);
356 for (unsigned I = 0, E = Handlers.size(); I != E; ++I) {
357 const HandlerInfo &OI = Handlers[I];
358 NamedRegionTimer T(OI.TimerName, OI.TimerGroupName, TimePassesIsEnabled);
359 OI.Handler->setSymbolSize(GVSym, Size);
360 }
362 // Handle common and BSS local symbols (.lcomm).
363 if (GVKind.isCommon() || GVKind.isBSSLocal()) {
364 if (Size == 0) Size = 1; // .comm Foo, 0 is undefined, avoid it.
365 unsigned Align = 1 << AlignLog;
367 // Handle common symbols.
368 if (GVKind.isCommon()) {
369 if (!getObjFileLowering().getCommDirectiveSupportsAlignment())
370 Align = 0;
372 // .comm _foo, 42, 4
373 OutStreamer.EmitCommonSymbol(GVSym, Size, Align);
374 return;
375 }
377 // Handle local BSS symbols.
378 if (MAI->hasMachoZeroFillDirective()) {
379 const MCSection *TheSection =
380 getObjFileLowering().SectionForGlobal(GV, GVKind, *Mang, TM);
381 // .zerofill __DATA, __bss, _foo, 400, 5
382 OutStreamer.EmitZerofill(TheSection, GVSym, Size, Align);
383 return;
384 }
386 // Use .lcomm only if it supports user-specified alignment.
387 // Otherwise, while it would still be correct to use .lcomm in some
388 // cases (e.g. when Align == 1), the external assembler might enfore
389 // some -unknown- default alignment behavior, which could cause
390 // spurious differences between external and integrated assembler.
391 // Prefer to simply fall back to .local / .comm in this case.
392 if (MAI->getLCOMMDirectiveAlignmentType() != LCOMM::NoAlignment) {
393 // .lcomm _foo, 42
394 OutStreamer.EmitLocalCommonSymbol(GVSym, Size, Align);
395 return;
396 }
398 if (!getObjFileLowering().getCommDirectiveSupportsAlignment())
399 Align = 0;
401 // .local _foo
402 OutStreamer.EmitSymbolAttribute(GVSym, MCSA_Local);
403 // .comm _foo, 42, 4
404 OutStreamer.EmitCommonSymbol(GVSym, Size, Align);
405 return;
406 }
408 const MCSection *TheSection =
409 getObjFileLowering().SectionForGlobal(GV, GVKind, *Mang, TM);
411 // Handle the zerofill directive on darwin, which is a special form of BSS
412 // emission.
413 if (GVKind.isBSSExtern() && MAI->hasMachoZeroFillDirective()) {
414 if (Size == 0) Size = 1; // zerofill of 0 bytes is undefined.
416 // .globl _foo
417 OutStreamer.EmitSymbolAttribute(GVSym, MCSA_Global);
418 // .zerofill __DATA, __common, _foo, 400, 5
419 OutStreamer.EmitZerofill(TheSection, GVSym, Size, 1 << AlignLog);
420 return;
421 }
423 // Handle thread local data for mach-o which requires us to output an
424 // additional structure of data and mangle the original symbol so that we
425 // can reference it later.
426 //
427 // TODO: This should become an "emit thread local global" method on TLOF.
428 // All of this macho specific stuff should be sunk down into TLOFMachO and
429 // stuff like "TLSExtraDataSection" should no longer be part of the parent
430 // TLOF class. This will also make it more obvious that stuff like
431 // MCStreamer::EmitTBSSSymbol is macho specific and only called from macho
432 // specific code.
433 if (GVKind.isThreadLocal() && MAI->hasMachoTBSSDirective()) {
434 // Emit the .tbss symbol
435 MCSymbol *MangSym =
436 OutContext.GetOrCreateSymbol(GVSym->getName() + Twine("$tlv$init"));
438 if (GVKind.isThreadBSS()) {
439 TheSection = getObjFileLowering().getTLSBSSSection();
440 OutStreamer.EmitTBSSSymbol(TheSection, MangSym, Size, 1 << AlignLog);
441 } else if (GVKind.isThreadData()) {
442 OutStreamer.SwitchSection(TheSection);
444 EmitAlignment(AlignLog, GV);
445 OutStreamer.EmitLabel(MangSym);
447 EmitGlobalConstant(GV->getInitializer());
448 }
450 OutStreamer.AddBlankLine();
452 // Emit the variable struct for the runtime.
453 const MCSection *TLVSect
454 = getObjFileLowering().getTLSExtraDataSection();
456 OutStreamer.SwitchSection(TLVSect);
457 // Emit the linkage here.
458 EmitLinkage(GV, GVSym);
459 OutStreamer.EmitLabel(GVSym);
461 // Three pointers in size:
462 // - __tlv_bootstrap - used to make sure support exists
463 // - spare pointer, used when mapped by the runtime
464 // - pointer to mangled symbol above with initializer
465 unsigned PtrSize = DL->getPointerTypeSize(GV->getType());
466 OutStreamer.EmitSymbolValue(GetExternalSymbolSymbol("_tlv_bootstrap"),
467 PtrSize);
468 OutStreamer.EmitIntValue(0, PtrSize);
469 OutStreamer.EmitSymbolValue(MangSym, PtrSize);
471 OutStreamer.AddBlankLine();
472 return;
473 }
475 OutStreamer.SwitchSection(TheSection);
477 EmitLinkage(GV, GVSym);
478 EmitAlignment(AlignLog, GV);
480 OutStreamer.EmitLabel(GVSym);
482 EmitGlobalConstant(GV->getInitializer());
484 if (MAI->hasDotTypeDotSizeDirective())
485 // .size foo, 42
486 OutStreamer.EmitELFSize(GVSym, MCConstantExpr::Create(Size, OutContext));
488 OutStreamer.AddBlankLine();
489 }
491 /// EmitFunctionHeader - This method emits the header for the current
492 /// function.
493 void AsmPrinter::EmitFunctionHeader() {
494 // Print out constants referenced by the function
495 EmitConstantPool();
497 // Print the 'header' of function.
498 const Function *F = MF->getFunction();
500 OutStreamer.SwitchSection(
501 getObjFileLowering().SectionForGlobal(F, *Mang, TM));
502 EmitVisibility(CurrentFnSym, F->getVisibility());
504 EmitLinkage(F, CurrentFnSym);
505 EmitAlignment(MF->getAlignment(), F);
507 if (MAI->hasDotTypeDotSizeDirective())
508 OutStreamer.EmitSymbolAttribute(CurrentFnSym, MCSA_ELF_TypeFunction);
510 if (isVerbose()) {
511 F->printAsOperand(OutStreamer.GetCommentOS(),
512 /*PrintType=*/false, F->getParent());
513 OutStreamer.GetCommentOS() << '\n';
514 }
516 // Emit the CurrentFnSym. This is a virtual function to allow targets to
517 // do their wild and crazy things as required.
518 EmitFunctionEntryLabel();
520 // If the function had address-taken blocks that got deleted, then we have
521 // references to the dangling symbols. Emit them at the start of the function
522 // so that we don't get references to undefined symbols.
523 std::vector<MCSymbol*> DeadBlockSyms;
524 MMI->takeDeletedSymbolsForFunction(F, DeadBlockSyms);
525 for (unsigned i = 0, e = DeadBlockSyms.size(); i != e; ++i) {
526 OutStreamer.AddComment("Address taken block that was later removed");
527 OutStreamer.EmitLabel(DeadBlockSyms[i]);
528 }
530 // Emit pre-function debug and/or EH information.
531 for (unsigned I = 0, E = Handlers.size(); I != E; ++I) {
532 const HandlerInfo &OI = Handlers[I];
533 NamedRegionTimer T(OI.TimerName, OI.TimerGroupName, TimePassesIsEnabled);
534 OI.Handler->beginFunction(MF);
535 }
537 // Emit the prefix data.
538 if (F->hasPrefixData())
539 EmitGlobalConstant(F->getPrefixData());
540 }
542 /// EmitFunctionEntryLabel - Emit the label that is the entrypoint for the
543 /// function. This can be overridden by targets as required to do custom stuff.
544 void AsmPrinter::EmitFunctionEntryLabel() {
545 // The function label could have already been emitted if two symbols end up
546 // conflicting due to asm renaming. Detect this and emit an error.
547 if (CurrentFnSym->isUndefined())
548 return OutStreamer.EmitLabel(CurrentFnSym);
550 report_fatal_error("'" + Twine(CurrentFnSym->getName()) +
551 "' label emitted multiple times to assembly file");
552 }
554 /// emitComments - Pretty-print comments for instructions.
555 static void emitComments(const MachineInstr &MI, raw_ostream &CommentOS) {
556 const MachineFunction *MF = MI.getParent()->getParent();
557 const TargetMachine &TM = MF->getTarget();
559 // Check for spills and reloads
560 int FI;
562 const MachineFrameInfo *FrameInfo = MF->getFrameInfo();
564 // We assume a single instruction only has a spill or reload, not
565 // both.
566 const MachineMemOperand *MMO;
567 if (TM.getInstrInfo()->isLoadFromStackSlotPostFE(&MI, FI)) {
568 if (FrameInfo->isSpillSlotObjectIndex(FI)) {
569 MMO = *MI.memoperands_begin();
570 CommentOS << MMO->getSize() << "-byte Reload\n";
571 }
572 } else if (TM.getInstrInfo()->hasLoadFromStackSlot(&MI, MMO, FI)) {
573 if (FrameInfo->isSpillSlotObjectIndex(FI))
574 CommentOS << MMO->getSize() << "-byte Folded Reload\n";
575 } else if (TM.getInstrInfo()->isStoreToStackSlotPostFE(&MI, FI)) {
576 if (FrameInfo->isSpillSlotObjectIndex(FI)) {
577 MMO = *MI.memoperands_begin();
578 CommentOS << MMO->getSize() << "-byte Spill\n";
579 }
580 } else if (TM.getInstrInfo()->hasStoreToStackSlot(&MI, MMO, FI)) {
581 if (FrameInfo->isSpillSlotObjectIndex(FI))
582 CommentOS << MMO->getSize() << "-byte Folded Spill\n";
583 }
585 // Check for spill-induced copies
586 if (MI.getAsmPrinterFlag(MachineInstr::ReloadReuse))
587 CommentOS << " Reload Reuse\n";
588 }
590 /// emitImplicitDef - This method emits the specified machine instruction
591 /// that is an implicit def.
592 void AsmPrinter::emitImplicitDef(const MachineInstr *MI) const {
593 unsigned RegNo = MI->getOperand(0).getReg();
594 OutStreamer.AddComment(Twine("implicit-def: ") +
595 TM.getRegisterInfo()->getName(RegNo));
596 OutStreamer.AddBlankLine();
597 }
599 static void emitKill(const MachineInstr *MI, AsmPrinter &AP) {
600 std::string Str = "kill:";
601 for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
602 const MachineOperand &Op = MI->getOperand(i);
603 assert(Op.isReg() && "KILL instruction must have only register operands");
604 Str += ' ';
605 Str += AP.TM.getRegisterInfo()->getName(Op.getReg());
606 Str += (Op.isDef() ? "<def>" : "<kill>");
607 }
608 AP.OutStreamer.AddComment(Str);
609 AP.OutStreamer.AddBlankLine();
610 }
612 /// emitDebugValueComment - This method handles the target-independent form
613 /// of DBG_VALUE, returning true if it was able to do so. A false return
614 /// means the target will need to handle MI in EmitInstruction.
615 static bool emitDebugValueComment(const MachineInstr *MI, AsmPrinter &AP) {
616 // This code handles only the 3-operand target-independent form.
617 if (MI->getNumOperands() != 3)
618 return false;
620 SmallString<128> Str;
621 raw_svector_ostream OS(Str);
622 OS << "DEBUG_VALUE: ";
624 DIVariable V(MI->getOperand(2).getMetadata());
625 if (V.getContext().isSubprogram()) {
626 StringRef Name = DISubprogram(V.getContext()).getDisplayName();
627 if (!Name.empty())
628 OS << Name << ":";
629 }
630 OS << V.getName() << " <- ";
632 // The second operand is only an offset if it's an immediate.
633 bool Deref = MI->getOperand(0).isReg() && MI->getOperand(1).isImm();
634 int64_t Offset = Deref ? MI->getOperand(1).getImm() : 0;
636 // Register or immediate value. Register 0 means undef.
637 if (MI->getOperand(0).isFPImm()) {
638 APFloat APF = APFloat(MI->getOperand(0).getFPImm()->getValueAPF());
639 if (MI->getOperand(0).getFPImm()->getType()->isFloatTy()) {
640 OS << (double)APF.convertToFloat();
641 } else if (MI->getOperand(0).getFPImm()->getType()->isDoubleTy()) {
642 OS << APF.convertToDouble();
643 } else {
644 // There is no good way to print long double. Convert a copy to
645 // double. Ah well, it's only a comment.
646 bool ignored;
647 APF.convert(APFloat::IEEEdouble, APFloat::rmNearestTiesToEven,
648 &ignored);
649 OS << "(long double) " << APF.convertToDouble();
650 }
651 } else if (MI->getOperand(0).isImm()) {
652 OS << MI->getOperand(0).getImm();
653 } else if (MI->getOperand(0).isCImm()) {
654 MI->getOperand(0).getCImm()->getValue().print(OS, false /*isSigned*/);
655 } else {
656 unsigned Reg;
657 if (MI->getOperand(0).isReg()) {
658 Reg = MI->getOperand(0).getReg();
659 } else {
660 assert(MI->getOperand(0).isFI() && "Unknown operand type");
661 const TargetFrameLowering *TFI = AP.TM.getFrameLowering();
662 Offset += TFI->getFrameIndexReference(*AP.MF,
663 MI->getOperand(0).getIndex(), Reg);
664 Deref = true;
665 }
666 if (Reg == 0) {
667 // Suppress offset, it is not meaningful here.
668 OS << "undef";
669 // NOTE: Want this comment at start of line, don't emit with AddComment.
670 AP.OutStreamer.emitRawComment(OS.str());
671 return true;
672 }
673 if (Deref)
674 OS << '[';
675 OS << AP.TM.getRegisterInfo()->getName(Reg);
676 }
678 if (Deref)
679 OS << '+' << Offset << ']';
681 // NOTE: Want this comment at start of line, don't emit with AddComment.
682 AP.OutStreamer.emitRawComment(OS.str());
683 return true;
684 }
686 AsmPrinter::CFIMoveType AsmPrinter::needsCFIMoves() {
687 if (MAI->getExceptionHandlingType() == ExceptionHandling::DwarfCFI &&
688 MF->getFunction()->needsUnwindTableEntry())
689 return CFI_M_EH;
691 if (MMI->hasDebugInfo())
692 return CFI_M_Debug;
694 return CFI_M_None;
695 }
697 bool AsmPrinter::needsSEHMoves() {
698 return MAI->getExceptionHandlingType() == ExceptionHandling::Win64 &&
699 MF->getFunction()->needsUnwindTableEntry();
700 }
702 void AsmPrinter::emitPrologLabel(const MachineInstr &MI) {
703 const MCSymbol *Label = MI.getOperand(0).getMCSymbol();
705 ExceptionHandling::ExceptionsType ExceptionHandlingType =
706 MAI->getExceptionHandlingType();
707 if (ExceptionHandlingType != ExceptionHandling::DwarfCFI &&
708 ExceptionHandlingType != ExceptionHandling::ARM)
709 return;
711 if (needsCFIMoves() == CFI_M_None)
712 return;
714 if (MMI->getCompactUnwindEncoding() != 0)
715 OutStreamer.EmitCompactUnwindEncoding(MMI->getCompactUnwindEncoding());
717 const MachineModuleInfo &MMI = MF->getMMI();
718 const std::vector<MCCFIInstruction> &Instrs = MMI.getFrameInstructions();
719 bool FoundOne = false;
720 (void)FoundOne;
721 for (std::vector<MCCFIInstruction>::const_iterator I = Instrs.begin(),
722 E = Instrs.end(); I != E; ++I) {
723 if (I->getLabel() == Label) {
724 emitCFIInstruction(*I);
725 FoundOne = true;
726 }
727 }
728 assert(FoundOne);
729 }
731 /// EmitFunctionBody - This method emits the body and trailer for a
732 /// function.
733 void AsmPrinter::EmitFunctionBody() {
734 // Emit target-specific gunk before the function body.
735 EmitFunctionBodyStart();
737 bool ShouldPrintDebugScopes = MMI->hasDebugInfo();
739 // Print out code for the function.
740 bool HasAnyRealCode = false;
741 const MachineInstr *LastMI = 0;
742 for (MachineFunction::const_iterator I = MF->begin(), E = MF->end();
743 I != E; ++I) {
744 // Print a label for the basic block.
745 EmitBasicBlockStart(I);
746 for (MachineBasicBlock::const_iterator II = I->begin(), IE = I->end();
747 II != IE; ++II) {
748 LastMI = II;
750 // Print the assembly for the instruction.
751 if (!II->isLabel() && !II->isImplicitDef() && !II->isKill() &&
752 !II->isDebugValue()) {
753 HasAnyRealCode = true;
754 ++EmittedInsts;
755 }
757 if (ShouldPrintDebugScopes) {
758 for (unsigned III = 0, EEE = Handlers.size(); III != EEE; ++III) {
759 const HandlerInfo &OI = Handlers[III];
760 NamedRegionTimer T(OI.TimerName, OI.TimerGroupName,
761 TimePassesIsEnabled);
762 OI.Handler->beginInstruction(II);
763 }
764 }
766 if (isVerbose())
767 emitComments(*II, OutStreamer.GetCommentOS());
769 switch (II->getOpcode()) {
770 case TargetOpcode::PROLOG_LABEL:
771 emitPrologLabel(*II);
772 break;
774 case TargetOpcode::EH_LABEL:
775 case TargetOpcode::GC_LABEL:
776 OutStreamer.EmitLabel(II->getOperand(0).getMCSymbol());
777 break;
778 case TargetOpcode::INLINEASM:
779 EmitInlineAsm(II);
780 break;
781 case TargetOpcode::DBG_VALUE:
782 if (isVerbose()) {
783 if (!emitDebugValueComment(II, *this))
784 EmitInstruction(II);
785 }
786 break;
787 case TargetOpcode::IMPLICIT_DEF:
788 if (isVerbose()) emitImplicitDef(II);
789 break;
790 case TargetOpcode::KILL:
791 if (isVerbose()) emitKill(II, *this);
792 break;
793 default:
794 EmitInstruction(II);
795 break;
796 }
798 if (ShouldPrintDebugScopes) {
799 for (unsigned III = 0, EEE = Handlers.size(); III != EEE; ++III) {
800 const HandlerInfo &OI = Handlers[III];
801 NamedRegionTimer T(OI.TimerName, OI.TimerGroupName,
802 TimePassesIsEnabled);
803 OI.Handler->endInstruction();
804 }
805 }
806 }
807 }
809 // If the last instruction was a prolog label, then we have a situation where
810 // we emitted a prolog but no function body. This results in the ending prolog
811 // label equaling the end of function label and an invalid "row" in the
812 // FDE. We need to emit a noop in this situation so that the FDE's rows are
813 // valid.
814 bool RequiresNoop = LastMI && LastMI->isPrologLabel();
816 // If the function is empty and the object file uses .subsections_via_symbols,
817 // then we need to emit *something* to the function body to prevent the
818 // labels from collapsing together. Just emit a noop.
819 if ((MAI->hasSubsectionsViaSymbols() && !HasAnyRealCode) || RequiresNoop) {
820 MCInst Noop;
821 TM.getInstrInfo()->getNoopForMachoTarget(Noop);
822 if (Noop.getOpcode()) {
823 OutStreamer.AddComment("avoids zero-length function");
824 OutStreamer.EmitInstruction(Noop, getSubtargetInfo());
825 } else // Target not mc-ized yet.
826 OutStreamer.EmitRawText(StringRef("\tnop\n"));
827 }
829 const Function *F = MF->getFunction();
830 for (Function::const_iterator i = F->begin(), e = F->end(); i != e; ++i) {
831 const BasicBlock *BB = i;
832 if (!BB->hasAddressTaken())
833 continue;
834 MCSymbol *Sym = GetBlockAddressSymbol(BB);
835 if (Sym->isDefined())
836 continue;
837 OutStreamer.AddComment("Address of block that was removed by CodeGen");
838 OutStreamer.EmitLabel(Sym);
839 }
841 // Emit target-specific gunk after the function body.
842 EmitFunctionBodyEnd();
844 // If the target wants a .size directive for the size of the function, emit
845 // it.
846 if (MAI->hasDotTypeDotSizeDirective()) {
847 // Create a symbol for the end of function, so we can get the size as
848 // difference between the function label and the temp label.
849 MCSymbol *FnEndLabel = OutContext.CreateTempSymbol();
850 OutStreamer.EmitLabel(FnEndLabel);
852 const MCExpr *SizeExp =
853 MCBinaryExpr::CreateSub(MCSymbolRefExpr::Create(FnEndLabel, OutContext),
854 MCSymbolRefExpr::Create(CurrentFnSymForSize,
855 OutContext),
856 OutContext);
857 OutStreamer.EmitELFSize(CurrentFnSym, SizeExp);
858 }
860 // Emit post-function debug and/or EH information.
861 for (unsigned I = 0, E = Handlers.size(); I != E; ++I) {
862 const HandlerInfo &OI = Handlers[I];
863 NamedRegionTimer T(OI.TimerName, OI.TimerGroupName, TimePassesIsEnabled);
864 OI.Handler->endFunction(MF);
865 }
866 MMI->EndFunction();
868 // Print out jump tables referenced by the function.
869 EmitJumpTableInfo();
871 OutStreamer.AddBlankLine();
872 }
874 /// Emit a dwarf register operation.
875 static void emitDwarfRegOp(const AsmPrinter &AP, int Reg) {
876 assert(Reg >= 0);
877 if (Reg < 32) {
878 AP.OutStreamer.AddComment(dwarf::
879 OperationEncodingString(dwarf::DW_OP_reg0 + Reg));
880 AP.EmitInt8(dwarf::DW_OP_reg0 + Reg);
881 } else {
882 AP.OutStreamer.AddComment("DW_OP_regx");
883 AP.EmitInt8(dwarf::DW_OP_regx);
884 AP.OutStreamer.AddComment(Twine(Reg));
885 AP.EmitULEB128(Reg);
886 }
887 }
889 /// Emit an (double-)indirect dwarf register operation.
890 static void emitDwarfRegOpIndirect(const AsmPrinter &AP,
891 int Reg, unsigned Offset, bool Deref) {
892 assert(Reg >= 0);
893 if (Reg < 32) {
894 AP.OutStreamer.AddComment(dwarf::
895 OperationEncodingString(dwarf::DW_OP_breg0 + Reg));
896 AP.EmitInt8(dwarf::DW_OP_breg0 + Reg);
897 } else {
898 AP.OutStreamer.AddComment("DW_OP_bregx");
899 AP.EmitInt8(dwarf::DW_OP_bregx);
900 AP.OutStreamer.AddComment(Twine(Reg));
901 AP.EmitULEB128(Reg);
902 }
903 AP.EmitSLEB128(Offset);
904 if (Deref)
905 AP.EmitInt8(dwarf::DW_OP_deref);
906 }
908 /// Emit a dwarf register operation for describing
909 /// - a small value occupying only part of a register or
910 /// - a small register representing only part of a value.
911 static void emitDwarfRegOpPiece(const AsmPrinter &AP,
912 int Reg, unsigned Size, unsigned Offset) {
913 assert(Reg >= 0);
914 assert(Size > 0);
916 emitDwarfRegOp(AP, Reg);
917 // Emit Mask
918 if (Offset > 0) {
919 AP.OutStreamer.AddComment("DW_OP_bit_piece");
920 AP.EmitInt8(dwarf::DW_OP_bit_piece);
921 AP.OutStreamer.AddComment(Twine(Size));
922 AP.EmitULEB128(Size);
923 AP.OutStreamer.AddComment(Twine(Offset));
924 AP.EmitULEB128(Offset);
925 } else {
926 AP.OutStreamer.AddComment("DW_OP_piece");
927 AP.EmitInt8(dwarf::DW_OP_piece);
928 unsigned ByteSize = Size / 8; // Assuming 8 bits per byte.
929 AP.OutStreamer.AddComment(Twine(ByteSize));
930 AP.EmitULEB128(ByteSize);
931 }
932 }
934 /// EmitDwarfRegOp - Emit dwarf register operation.
935 void AsmPrinter::EmitDwarfRegOp(const MachineLocation &MLoc,
936 bool Indirect) const {
937 const TargetRegisterInfo *TRI = TM.getRegisterInfo();
938 int Reg = TRI->getDwarfRegNum(MLoc.getReg(), false);
940 if (Reg < 0) {
941 // Walk up the super-register chain until we find a valid number.
942 for (MCSuperRegIterator SR(MLoc.getReg(), TRI); SR.isValid(); ++SR) {
943 Reg = TRI->getDwarfRegNum(*SR, false);
944 if (Reg >= 0) {
945 unsigned Idx = TRI->getSubRegIndex(*SR, MLoc.getReg());
946 unsigned Size = TRI->getSubRegIdxSize(Idx);
947 unsigned Offset = TRI->getSubRegIdxOffset(Idx);
948 emitDwarfRegOpPiece(*this, Reg, Size, Offset);
950 if (MLoc.isIndirect())
951 EmitInt8(dwarf::DW_OP_deref);
953 if (Indirect)
954 EmitInt8(dwarf::DW_OP_deref);
956 return;
957 }
959 // FIXME: Handle cases like a super register being encoded as
960 // DW_OP_reg 32 DW_OP_piece 4 DW_OP_reg 33
962 }
963 // FIXME: We have no reasonable way of handling errors in here. The
964 // caller might be in the middle of an dwarf expression. We should
965 // probably assert that Reg >= 0 once debug info generation is more mature.
966 OutStreamer.AddComment("nop (invalid dwarf register number)");
967 EmitInt8(dwarf::DW_OP_nop);
968 return;
969 }
971 if (MLoc.isIndirect())
972 emitDwarfRegOpIndirect(*this, Reg, MLoc.getOffset(), Indirect);
973 else if (Indirect)
974 emitDwarfRegOpIndirect(*this, Reg, 0, false);
975 else
976 emitDwarfRegOp(*this, Reg);
977 }
979 bool AsmPrinter::doFinalization(Module &M) {
980 // Emit global variables.
981 for (Module::const_global_iterator I = M.global_begin(), E = M.global_end();
982 I != E; ++I)
983 EmitGlobalVariable(I);
985 // Emit visibility info for declarations
986 for (Module::const_iterator I = M.begin(), E = M.end(); I != E; ++I) {
987 const Function &F = *I;
988 if (!F.isDeclaration())
989 continue;
990 GlobalValue::VisibilityTypes V = F.getVisibility();
991 if (V == GlobalValue::DefaultVisibility)
992 continue;
994 MCSymbol *Name = getSymbol(&F);
995 EmitVisibility(Name, V, false);
996 }
998 // Emit module flags.
999 SmallVector<Module::ModuleFlagEntry, 8> ModuleFlags;
1000 M.getModuleFlagsMetadata(ModuleFlags);
1001 if (!ModuleFlags.empty())
1002 getObjFileLowering().emitModuleFlags(OutStreamer, ModuleFlags, *Mang, TM);
1004 // Make sure we wrote out everything we need.
1005 OutStreamer.Flush();
1007 // Finalize debug and EH information.
1008 for (unsigned I = 0, E = Handlers.size(); I != E; ++I) {
1009 const HandlerInfo &OI = Handlers[I];
1010 NamedRegionTimer T(OI.TimerName, OI.TimerGroupName,
1011 TimePassesIsEnabled);
1012 OI.Handler->endModule();
1013 delete OI.Handler;
1014 }
1015 Handlers.clear();
1016 DD = 0;
1018 // If the target wants to know about weak references, print them all.
1019 if (MAI->getWeakRefDirective()) {
1020 // FIXME: This is not lazy, it would be nice to only print weak references
1021 // to stuff that is actually used. Note that doing so would require targets
1022 // to notice uses in operands (due to constant exprs etc). This should
1023 // happen with the MC stuff eventually.
1025 // Print out module-level global variables here.
1026 for (Module::const_global_iterator I = M.global_begin(), E = M.global_end();
1027 I != E; ++I) {
1028 if (!I->hasExternalWeakLinkage()) continue;
1029 OutStreamer.EmitSymbolAttribute(getSymbol(I), MCSA_WeakReference);
1030 }
1032 for (Module::const_iterator I = M.begin(), E = M.end(); I != E; ++I) {
1033 if (!I->hasExternalWeakLinkage()) continue;
1034 OutStreamer.EmitSymbolAttribute(getSymbol(I), MCSA_WeakReference);
1035 }
1036 }
1038 if (MAI->hasSetDirective()) {
1039 OutStreamer.AddBlankLine();
1040 for (Module::const_alias_iterator I = M.alias_begin(), E = M.alias_end();
1041 I != E; ++I) {
1042 MCSymbol *Name = getSymbol(I);
1044 const GlobalValue *GV = I->getAliasedGlobal();
1045 if (GV->isDeclaration()) {
1046 report_fatal_error(Name->getName() +
1047 ": Target doesn't support aliases to declarations");
1048 }
1050 MCSymbol *Target = getSymbol(GV);
1052 if (I->hasExternalLinkage() || !MAI->getWeakRefDirective())
1053 OutStreamer.EmitSymbolAttribute(Name, MCSA_Global);
1054 else if (I->hasWeakLinkage() || I->hasLinkOnceLinkage())
1055 OutStreamer.EmitSymbolAttribute(Name, MCSA_WeakReference);
1056 else
1057 assert(I->hasLocalLinkage() && "Invalid alias linkage");
1059 EmitVisibility(Name, I->getVisibility());
1061 // Emit the directives as assignments aka .set:
1062 OutStreamer.EmitAssignment(Name,
1063 MCSymbolRefExpr::Create(Target, OutContext));
1064 }
1065 }
1067 GCModuleInfo *MI = getAnalysisIfAvailable<GCModuleInfo>();
1068 assert(MI && "AsmPrinter didn't require GCModuleInfo?");
1069 for (GCModuleInfo::iterator I = MI->end(), E = MI->begin(); I != E; )
1070 if (GCMetadataPrinter *MP = GetOrCreateGCPrinter(*--I))
1071 MP->finishAssembly(*this);
1073 // Emit llvm.ident metadata in an '.ident' directive.
1074 EmitModuleIdents(M);
1076 // If we don't have any trampolines, then we don't require stack memory
1077 // to be executable. Some targets have a directive to declare this.
1078 Function *InitTrampolineIntrinsic = M.getFunction("llvm.init.trampoline");
1079 if (!InitTrampolineIntrinsic || InitTrampolineIntrinsic->use_empty())
1080 if (const MCSection *S = MAI->getNonexecutableStackSection(OutContext))
1081 OutStreamer.SwitchSection(S);
1083 // Allow the target to emit any magic that it wants at the end of the file,
1084 // after everything else has gone out.
1085 EmitEndOfAsmFile(M);
1087 delete Mang; Mang = 0;
1088 MMI = 0;
1090 OutStreamer.Finish();
1091 OutStreamer.reset();
1093 return false;
1094 }
1096 void AsmPrinter::SetupMachineFunction(MachineFunction &MF) {
1097 this->MF = &MF;
1098 // Get the function symbol.
1099 CurrentFnSym = getSymbol(MF.getFunction());
1100 CurrentFnSymForSize = CurrentFnSym;
1102 if (isVerbose())
1103 LI = &getAnalysis<MachineLoopInfo>();
1104 }
1106 namespace {
1107 // SectionCPs - Keep track the alignment, constpool entries per Section.
1108 struct SectionCPs {
1109 const MCSection *S;
1110 unsigned Alignment;
1111 SmallVector<unsigned, 4> CPEs;
1112 SectionCPs(const MCSection *s, unsigned a) : S(s), Alignment(a) {}
1113 };
1114 }
1116 /// EmitConstantPool - Print to the current output stream assembly
1117 /// representations of the constants in the constant pool MCP. This is
1118 /// used to print out constants which have been "spilled to memory" by
1119 /// the code generator.
1120 ///
1121 void AsmPrinter::EmitConstantPool() {
1122 const MachineConstantPool *MCP = MF->getConstantPool();
1123 const std::vector<MachineConstantPoolEntry> &CP = MCP->getConstants();
1124 if (CP.empty()) return;
1126 // Calculate sections for constant pool entries. We collect entries to go into
1127 // the same section together to reduce amount of section switch statements.
1128 SmallVector<SectionCPs, 4> CPSections;
1129 for (unsigned i = 0, e = CP.size(); i != e; ++i) {
1130 const MachineConstantPoolEntry &CPE = CP[i];
1131 unsigned Align = CPE.getAlignment();
1133 SectionKind Kind;
1134 switch (CPE.getRelocationInfo()) {
1135 default: llvm_unreachable("Unknown section kind");
1136 case 2: Kind = SectionKind::getReadOnlyWithRel(); break;
1137 case 1:
1138 Kind = SectionKind::getReadOnlyWithRelLocal();
1139 break;
1140 case 0:
1141 switch (TM.getDataLayout()->getTypeAllocSize(CPE.getType())) {
1142 case 4: Kind = SectionKind::getMergeableConst4(); break;
1143 case 8: Kind = SectionKind::getMergeableConst8(); break;
1144 case 16: Kind = SectionKind::getMergeableConst16();break;
1145 default: Kind = SectionKind::getMergeableConst(); break;
1146 }
1147 }
1149 const MCSection *S = getObjFileLowering().getSectionForConstant(Kind);
1151 // The number of sections are small, just do a linear search from the
1152 // last section to the first.
1153 bool Found = false;
1154 unsigned SecIdx = CPSections.size();
1155 while (SecIdx != 0) {
1156 if (CPSections[--SecIdx].S == S) {
1157 Found = true;
1158 break;
1159 }
1160 }
1161 if (!Found) {
1162 SecIdx = CPSections.size();
1163 CPSections.push_back(SectionCPs(S, Align));
1164 }
1166 if (Align > CPSections[SecIdx].Alignment)
1167 CPSections[SecIdx].Alignment = Align;
1168 CPSections[SecIdx].CPEs.push_back(i);
1169 }
1171 // Now print stuff into the calculated sections.
1172 for (unsigned i = 0, e = CPSections.size(); i != e; ++i) {
1173 OutStreamer.SwitchSection(CPSections[i].S);
1174 EmitAlignment(Log2_32(CPSections[i].Alignment));
1176 unsigned Offset = 0;
1177 for (unsigned j = 0, ee = CPSections[i].CPEs.size(); j != ee; ++j) {
1178 unsigned CPI = CPSections[i].CPEs[j];
1179 MachineConstantPoolEntry CPE = CP[CPI];
1181 // Emit inter-object padding for alignment.
1182 unsigned AlignMask = CPE.getAlignment() - 1;
1183 unsigned NewOffset = (Offset + AlignMask) & ~AlignMask;
1184 OutStreamer.EmitZeros(NewOffset - Offset);
1186 Type *Ty = CPE.getType();
1187 Offset = NewOffset + TM.getDataLayout()->getTypeAllocSize(Ty);
1188 OutStreamer.EmitLabel(GetCPISymbol(CPI));
1190 if (CPE.isMachineConstantPoolEntry())
1191 EmitMachineConstantPoolValue(CPE.Val.MachineCPVal);
1192 else
1193 EmitGlobalConstant(CPE.Val.ConstVal);
1194 }
1195 }
1196 }
1198 /// EmitJumpTableInfo - Print assembly representations of the jump tables used
1199 /// by the current function to the current output stream.
1200 ///
1201 void AsmPrinter::EmitJumpTableInfo() {
1202 const DataLayout *DL = MF->getTarget().getDataLayout();
1203 const MachineJumpTableInfo *MJTI = MF->getJumpTableInfo();
1204 if (MJTI == 0) return;
1205 if (MJTI->getEntryKind() == MachineJumpTableInfo::EK_Inline) return;
1206 const std::vector<MachineJumpTableEntry> &JT = MJTI->getJumpTables();
1207 if (JT.empty()) return;
1209 // Pick the directive to use to print the jump table entries, and switch to
1210 // the appropriate section.
1211 const Function *F = MF->getFunction();
1212 bool JTInDiffSection = false;
1213 if (// In PIC mode, we need to emit the jump table to the same section as the
1214 // function body itself, otherwise the label differences won't make sense.
1215 // FIXME: Need a better predicate for this: what about custom entries?
1216 MJTI->getEntryKind() == MachineJumpTableInfo::EK_LabelDifference32 ||
1217 // We should also do if the section name is NULL or function is declared
1218 // in discardable section
1219 // FIXME: this isn't the right predicate, should be based on the MCSection
1220 // for the function.
1221 F->isWeakForLinker()) {
1222 OutStreamer.SwitchSection(
1223 getObjFileLowering().SectionForGlobal(F, *Mang, TM));
1224 } else {
1225 // Otherwise, drop it in the readonly section.
1226 const MCSection *ReadOnlySection =
1227 getObjFileLowering().getSectionForConstant(SectionKind::getReadOnly());
1228 OutStreamer.SwitchSection(ReadOnlySection);
1229 JTInDiffSection = true;
1230 }
1232 EmitAlignment(Log2_32(MJTI->getEntryAlignment(*TM.getDataLayout())));
1234 // Jump tables in code sections are marked with a data_region directive
1235 // where that's supported.
1236 if (!JTInDiffSection)
1237 OutStreamer.EmitDataRegion(MCDR_DataRegionJT32);
1239 for (unsigned JTI = 0, e = JT.size(); JTI != e; ++JTI) {
1240 const std::vector<MachineBasicBlock*> &JTBBs = JT[JTI].MBBs;
1242 // If this jump table was deleted, ignore it.
1243 if (JTBBs.empty()) continue;
1245 // For the EK_LabelDifference32 entry, if the target supports .set, emit a
1246 // .set directive for each unique entry. This reduces the number of
1247 // relocations the assembler will generate for the jump table.
1248 if (MJTI->getEntryKind() == MachineJumpTableInfo::EK_LabelDifference32 &&
1249 MAI->hasSetDirective()) {
1250 SmallPtrSet<const MachineBasicBlock*, 16> EmittedSets;
1251 const TargetLowering *TLI = TM.getTargetLowering();
1252 const MCExpr *Base = TLI->getPICJumpTableRelocBaseExpr(MF,JTI,OutContext);
1253 for (unsigned ii = 0, ee = JTBBs.size(); ii != ee; ++ii) {
1254 const MachineBasicBlock *MBB = JTBBs[ii];
1255 if (!EmittedSets.insert(MBB)) continue;
1257 // .set LJTSet, LBB32-base
1258 const MCExpr *LHS =
1259 MCSymbolRefExpr::Create(MBB->getSymbol(), OutContext);
1260 OutStreamer.EmitAssignment(GetJTSetSymbol(JTI, MBB->getNumber()),
1261 MCBinaryExpr::CreateSub(LHS, Base, OutContext));
1262 }
1263 }
1265 // On some targets (e.g. Darwin) we want to emit two consecutive labels
1266 // before each jump table. The first label is never referenced, but tells
1267 // the assembler and linker the extents of the jump table object. The
1268 // second label is actually referenced by the code.
1269 if (JTInDiffSection && DL->hasLinkerPrivateGlobalPrefix())
1270 // FIXME: This doesn't have to have any specific name, just any randomly
1271 // named and numbered 'l' label would work. Simplify GetJTISymbol.
1272 OutStreamer.EmitLabel(GetJTISymbol(JTI, true));
1274 OutStreamer.EmitLabel(GetJTISymbol(JTI));
1276 for (unsigned ii = 0, ee = JTBBs.size(); ii != ee; ++ii)
1277 EmitJumpTableEntry(MJTI, JTBBs[ii], JTI);
1278 }
1279 if (!JTInDiffSection)
1280 OutStreamer.EmitDataRegion(MCDR_DataRegionEnd);
1281 }
1283 /// EmitJumpTableEntry - Emit a jump table entry for the specified MBB to the
1284 /// current stream.
1285 void AsmPrinter::EmitJumpTableEntry(const MachineJumpTableInfo *MJTI,
1286 const MachineBasicBlock *MBB,
1287 unsigned UID) const {
1288 assert(MBB && MBB->getNumber() >= 0 && "Invalid basic block");
1289 const MCExpr *Value = 0;
1290 switch (MJTI->getEntryKind()) {
1291 case MachineJumpTableInfo::EK_Inline:
1292 llvm_unreachable("Cannot emit EK_Inline jump table entry");
1293 case MachineJumpTableInfo::EK_Custom32:
1294 Value = TM.getTargetLowering()->LowerCustomJumpTableEntry(MJTI, MBB, UID,
1295 OutContext);
1296 break;
1297 case MachineJumpTableInfo::EK_BlockAddress:
1298 // EK_BlockAddress - Each entry is a plain address of block, e.g.:
1299 // .word LBB123
1300 Value = MCSymbolRefExpr::Create(MBB->getSymbol(), OutContext);
1301 break;
1302 case MachineJumpTableInfo::EK_GPRel32BlockAddress: {
1303 // EK_GPRel32BlockAddress - Each entry is an address of block, encoded
1304 // with a relocation as gp-relative, e.g.:
1305 // .gprel32 LBB123
1306 MCSymbol *MBBSym = MBB->getSymbol();
1307 OutStreamer.EmitGPRel32Value(MCSymbolRefExpr::Create(MBBSym, OutContext));
1308 return;
1309 }
1311 case MachineJumpTableInfo::EK_GPRel64BlockAddress: {
1312 // EK_GPRel64BlockAddress - Each entry is an address of block, encoded
1313 // with a relocation as gp-relative, e.g.:
1314 // .gpdword LBB123
1315 MCSymbol *MBBSym = MBB->getSymbol();
1316 OutStreamer.EmitGPRel64Value(MCSymbolRefExpr::Create(MBBSym, OutContext));
1317 return;
1318 }
1320 case MachineJumpTableInfo::EK_LabelDifference32: {
1321 // EK_LabelDifference32 - Each entry is the address of the block minus
1322 // the address of the jump table. This is used for PIC jump tables where
1323 // gprel32 is not supported. e.g.:
1324 // .word LBB123 - LJTI1_2
1325 // If the .set directive is supported, this is emitted as:
1326 // .set L4_5_set_123, LBB123 - LJTI1_2
1327 // .word L4_5_set_123
1329 // If we have emitted set directives for the jump table entries, print
1330 // them rather than the entries themselves. If we're emitting PIC, then
1331 // emit the table entries as differences between two text section labels.
1332 if (MAI->hasSetDirective()) {
1333 // If we used .set, reference the .set's symbol.
1334 Value = MCSymbolRefExpr::Create(GetJTSetSymbol(UID, MBB->getNumber()),
1335 OutContext);
1336 break;
1337 }
1338 // Otherwise, use the difference as the jump table entry.
1339 Value = MCSymbolRefExpr::Create(MBB->getSymbol(), OutContext);
1340 const MCExpr *JTI = MCSymbolRefExpr::Create(GetJTISymbol(UID), OutContext);
1341 Value = MCBinaryExpr::CreateSub(Value, JTI, OutContext);
1342 break;
1343 }
1344 }
1346 assert(Value && "Unknown entry kind!");
1348 unsigned EntrySize = MJTI->getEntrySize(*TM.getDataLayout());
1349 OutStreamer.EmitValue(Value, EntrySize);
1350 }
1353 /// EmitSpecialLLVMGlobal - Check to see if the specified global is a
1354 /// special global used by LLVM. If so, emit it and return true, otherwise
1355 /// do nothing and return false.
1356 bool AsmPrinter::EmitSpecialLLVMGlobal(const GlobalVariable *GV) {
1357 if (GV->getName() == "llvm.used") {
1358 if (MAI->hasNoDeadStrip()) // No need to emit this at all.
1359 EmitLLVMUsedList(cast<ConstantArray>(GV->getInitializer()));
1360 return true;
1361 }
1363 // Ignore debug and non-emitted data. This handles llvm.compiler.used.
1364 if (GV->getSection() == "llvm.metadata" ||
1365 GV->hasAvailableExternallyLinkage())
1366 return true;
1368 if (!GV->hasAppendingLinkage()) return false;
1370 assert(GV->hasInitializer() && "Not a special LLVM global!");
1372 if (GV->getName() == "llvm.global_ctors") {
1373 EmitXXStructorList(GV->getInitializer(), /* isCtor */ true);
1375 if (TM.getRelocationModel() == Reloc::Static &&
1376 MAI->hasStaticCtorDtorReferenceInStaticMode()) {
1377 StringRef Sym(".constructors_used");
1378 OutStreamer.EmitSymbolAttribute(OutContext.GetOrCreateSymbol(Sym),
1379 MCSA_Reference);
1380 }
1381 return true;
1382 }
1384 if (GV->getName() == "llvm.global_dtors") {
1385 EmitXXStructorList(GV->getInitializer(), /* isCtor */ false);
1387 if (TM.getRelocationModel() == Reloc::Static &&
1388 MAI->hasStaticCtorDtorReferenceInStaticMode()) {
1389 StringRef Sym(".destructors_used");
1390 OutStreamer.EmitSymbolAttribute(OutContext.GetOrCreateSymbol(Sym),
1391 MCSA_Reference);
1392 }
1393 return true;
1394 }
1396 return false;
1397 }
1399 /// EmitLLVMUsedList - For targets that define a MAI::UsedDirective, mark each
1400 /// global in the specified llvm.used list for which emitUsedDirectiveFor
1401 /// is true, as being used with this directive.
1402 void AsmPrinter::EmitLLVMUsedList(const ConstantArray *InitList) {
1403 // Should be an array of 'i8*'.
1404 for (unsigned i = 0, e = InitList->getNumOperands(); i != e; ++i) {
1405 const GlobalValue *GV =
1406 dyn_cast<GlobalValue>(InitList->getOperand(i)->stripPointerCasts());
1407 if (GV && getObjFileLowering().shouldEmitUsedDirectiveFor(GV, *Mang, TM))
1408 OutStreamer.EmitSymbolAttribute(getSymbol(GV), MCSA_NoDeadStrip);
1409 }
1410 }
1412 /// EmitXXStructorList - Emit the ctor or dtor list taking into account the init
1413 /// priority.
1414 void AsmPrinter::EmitXXStructorList(const Constant *List, bool isCtor) {
1415 // Should be an array of '{ int, void ()* }' structs. The first value is the
1416 // init priority.
1417 if (!isa<ConstantArray>(List)) return;
1419 // Sanity check the structors list.
1420 const ConstantArray *InitList = dyn_cast<ConstantArray>(List);
1421 if (!InitList) return; // Not an array!
1422 StructType *ETy = dyn_cast<StructType>(InitList->getType()->getElementType());
1423 if (!ETy || ETy->getNumElements() != 2) return; // Not an array of pairs!
1424 if (!isa<IntegerType>(ETy->getTypeAtIndex(0U)) ||
1425 !isa<PointerType>(ETy->getTypeAtIndex(1U))) return; // Not (int, ptr).
1427 // Gather the structors in a form that's convenient for sorting by priority.
1428 typedef std::pair<unsigned, Constant *> Structor;
1429 SmallVector<Structor, 8> Structors;
1430 for (unsigned i = 0, e = InitList->getNumOperands(); i != e; ++i) {
1431 ConstantStruct *CS = dyn_cast<ConstantStruct>(InitList->getOperand(i));
1432 if (!CS) continue; // Malformed.
1433 if (CS->getOperand(1)->isNullValue())
1434 break; // Found a null terminator, skip the rest.
1435 ConstantInt *Priority = dyn_cast<ConstantInt>(CS->getOperand(0));
1436 if (!Priority) continue; // Malformed.
1437 Structors.push_back(std::make_pair(Priority->getLimitedValue(65535),
1438 CS->getOperand(1)));
1439 }
1441 // Emit the function pointers in the target-specific order
1442 const DataLayout *DL = TM.getDataLayout();
1443 unsigned Align = Log2_32(DL->getPointerPrefAlignment());
1444 std::stable_sort(Structors.begin(), Structors.end(), less_first());
1445 for (unsigned i = 0, e = Structors.size(); i != e; ++i) {
1446 const MCSection *OutputSection =
1447 (isCtor ?
1448 getObjFileLowering().getStaticCtorSection(Structors[i].first) :
1449 getObjFileLowering().getStaticDtorSection(Structors[i].first));
1450 OutStreamer.SwitchSection(OutputSection);
1451 if (OutStreamer.getCurrentSection() != OutStreamer.getPreviousSection())
1452 EmitAlignment(Align);
1453 EmitXXStructor(Structors[i].second);
1454 }
1455 }
1457 void AsmPrinter::EmitModuleIdents(Module &M) {
1458 if (!MAI->hasIdentDirective())
1459 return;
1461 if (const NamedMDNode *NMD = M.getNamedMetadata("llvm.ident")) {
1462 for (unsigned i = 0, e = NMD->getNumOperands(); i != e; ++i) {
1463 const MDNode *N = NMD->getOperand(i);
1464 assert(N->getNumOperands() == 1 &&
1465 "llvm.ident metadata entry can have only one operand");
1466 const MDString *S = cast<MDString>(N->getOperand(0));
1467 OutStreamer.EmitIdent(S->getString());
1468 }
1469 }
1470 }
1472 //===--------------------------------------------------------------------===//
1473 // Emission and print routines
1474 //
1476 /// EmitInt8 - Emit a byte directive and value.
1477 ///
1478 void AsmPrinter::EmitInt8(int Value) const {
1479 OutStreamer.EmitIntValue(Value, 1);
1480 }
1482 /// EmitInt16 - Emit a short directive and value.
1483 ///
1484 void AsmPrinter::EmitInt16(int Value) const {
1485 OutStreamer.EmitIntValue(Value, 2);
1486 }
1488 /// EmitInt32 - Emit a long directive and value.
1489 ///
1490 void AsmPrinter::EmitInt32(int Value) const {
1491 OutStreamer.EmitIntValue(Value, 4);
1492 }
1494 /// EmitLabelDifference - Emit something like ".long Hi-Lo" where the size
1495 /// in bytes of the directive is specified by Size and Hi/Lo specify the
1496 /// labels. This implicitly uses .set if it is available.
1497 void AsmPrinter::EmitLabelDifference(const MCSymbol *Hi, const MCSymbol *Lo,
1498 unsigned Size) const {
1499 // Get the Hi-Lo expression.
1500 const MCExpr *Diff =
1501 MCBinaryExpr::CreateSub(MCSymbolRefExpr::Create(Hi, OutContext),
1502 MCSymbolRefExpr::Create(Lo, OutContext),
1503 OutContext);
1505 if (!MAI->hasSetDirective()) {
1506 OutStreamer.EmitValue(Diff, Size);
1507 return;
1508 }
1510 // Otherwise, emit with .set (aka assignment).
1511 MCSymbol *SetLabel = GetTempSymbol("set", SetCounter++);
1512 OutStreamer.EmitAssignment(SetLabel, Diff);
1513 OutStreamer.EmitSymbolValue(SetLabel, Size);
1514 }
1516 /// EmitLabelOffsetDifference - Emit something like ".long Hi+Offset-Lo"
1517 /// where the size in bytes of the directive is specified by Size and Hi/Lo
1518 /// specify the labels. This implicitly uses .set if it is available.
1519 void AsmPrinter::EmitLabelOffsetDifference(const MCSymbol *Hi, uint64_t Offset,
1520 const MCSymbol *Lo,
1521 unsigned Size) const {
1523 // Emit Hi+Offset - Lo
1524 // Get the Hi+Offset expression.
1525 const MCExpr *Plus =
1526 MCBinaryExpr::CreateAdd(MCSymbolRefExpr::Create(Hi, OutContext),
1527 MCConstantExpr::Create(Offset, OutContext),
1528 OutContext);
1530 // Get the Hi+Offset-Lo expression.
1531 const MCExpr *Diff =
1532 MCBinaryExpr::CreateSub(Plus,
1533 MCSymbolRefExpr::Create(Lo, OutContext),
1534 OutContext);
1536 if (!MAI->hasSetDirective())
1537 OutStreamer.EmitValue(Diff, Size);
1538 else {
1539 // Otherwise, emit with .set (aka assignment).
1540 MCSymbol *SetLabel = GetTempSymbol("set", SetCounter++);
1541 OutStreamer.EmitAssignment(SetLabel, Diff);
1542 OutStreamer.EmitSymbolValue(SetLabel, Size);
1543 }
1544 }
1546 /// EmitLabelPlusOffset - Emit something like ".long Label+Offset"
1547 /// where the size in bytes of the directive is specified by Size and Label
1548 /// specifies the label. This implicitly uses .set if it is available.
1549 void AsmPrinter::EmitLabelPlusOffset(const MCSymbol *Label, uint64_t Offset,
1550 unsigned Size,
1551 bool IsSectionRelative) const {
1552 if (MAI->needsDwarfSectionOffsetDirective() && IsSectionRelative) {
1553 OutStreamer.EmitCOFFSecRel32(Label);
1554 return;
1555 }
1557 // Emit Label+Offset (or just Label if Offset is zero)
1558 const MCExpr *Expr = MCSymbolRefExpr::Create(Label, OutContext);
1559 if (Offset)
1560 Expr = MCBinaryExpr::CreateAdd(
1561 Expr, MCConstantExpr::Create(Offset, OutContext), OutContext);
1563 OutStreamer.EmitValue(Expr, Size);
1564 }
1566 //===----------------------------------------------------------------------===//
1568 // EmitAlignment - Emit an alignment directive to the specified power of
1569 // two boundary. For example, if you pass in 3 here, you will get an 8
1570 // byte alignment. If a global value is specified, and if that global has
1571 // an explicit alignment requested, it will override the alignment request
1572 // if required for correctness.
1573 //
1574 void AsmPrinter::EmitAlignment(unsigned NumBits, const GlobalValue *GV) const {
1575 if (GV) NumBits = getGVAlignmentLog2(GV, *TM.getDataLayout(), NumBits);
1577 if (NumBits == 0) return; // 1-byte aligned: no need to emit alignment.
1579 if (getCurrentSection()->getKind().isText())
1580 OutStreamer.EmitCodeAlignment(1 << NumBits);
1581 else
1582 OutStreamer.EmitValueToAlignment(1 << NumBits);
1583 }
1585 //===----------------------------------------------------------------------===//
1586 // Constant emission.
1587 //===----------------------------------------------------------------------===//
1589 /// lowerConstant - Lower the specified LLVM Constant to an MCExpr.
1590 ///
1591 static const MCExpr *lowerConstant(const Constant *CV, AsmPrinter &AP) {
1592 MCContext &Ctx = AP.OutContext;
1594 if (CV->isNullValue() || isa<UndefValue>(CV))
1595 return MCConstantExpr::Create(0, Ctx);
1597 if (const ConstantInt *CI = dyn_cast<ConstantInt>(CV))
1598 return MCConstantExpr::Create(CI->getZExtValue(), Ctx);
1600 if (const GlobalValue *GV = dyn_cast<GlobalValue>(CV))
1601 return MCSymbolRefExpr::Create(AP.getSymbol(GV), Ctx);
1603 if (const BlockAddress *BA = dyn_cast<BlockAddress>(CV))
1604 return MCSymbolRefExpr::Create(AP.GetBlockAddressSymbol(BA), Ctx);
1606 const ConstantExpr *CE = dyn_cast<ConstantExpr>(CV);
1607 if (CE == 0) {
1608 llvm_unreachable("Unknown constant value to lower!");
1609 }
1611 if (const MCExpr *RelocExpr =
1612 AP.getObjFileLowering().getExecutableRelativeSymbol(CE, *AP.Mang,
1613 AP.TM))
1614 return RelocExpr;
1616 switch (CE->getOpcode()) {
1617 default:
1618 // If the code isn't optimized, there may be outstanding folding
1619 // opportunities. Attempt to fold the expression using DataLayout as a
1620 // last resort before giving up.
1621 if (Constant *C =
1622 ConstantFoldConstantExpression(CE, AP.TM.getDataLayout()))
1623 if (C != CE)
1624 return lowerConstant(C, AP);
1626 // Otherwise report the problem to the user.
1627 {
1628 std::string S;
1629 raw_string_ostream OS(S);
1630 OS << "Unsupported expression in static initializer: ";
1631 CE->printAsOperand(OS, /*PrintType=*/false,
1632 !AP.MF ? 0 : AP.MF->getFunction()->getParent());
1633 report_fatal_error(OS.str());
1634 }
1635 case Instruction::GetElementPtr: {
1636 const DataLayout &DL = *AP.TM.getDataLayout();
1637 // Generate a symbolic expression for the byte address
1638 APInt OffsetAI(DL.getPointerTypeSizeInBits(CE->getType()), 0);
1639 cast<GEPOperator>(CE)->accumulateConstantOffset(DL, OffsetAI);
1641 const MCExpr *Base = lowerConstant(CE->getOperand(0), AP);
1642 if (!OffsetAI)
1643 return Base;
1645 int64_t Offset = OffsetAI.getSExtValue();
1646 return MCBinaryExpr::CreateAdd(Base, MCConstantExpr::Create(Offset, Ctx),
1647 Ctx);
1648 }
1650 case Instruction::Trunc:
1651 // We emit the value and depend on the assembler to truncate the generated
1652 // expression properly. This is important for differences between
1653 // blockaddress labels. Since the two labels are in the same function, it
1654 // is reasonable to treat their delta as a 32-bit value.
1655 // FALL THROUGH.
1656 case Instruction::BitCast:
1657 return lowerConstant(CE->getOperand(0), AP);
1659 case Instruction::IntToPtr: {
1660 const DataLayout &DL = *AP.TM.getDataLayout();
1661 // Handle casts to pointers by changing them into casts to the appropriate
1662 // integer type. This promotes constant folding and simplifies this code.
1663 Constant *Op = CE->getOperand(0);
1664 Op = ConstantExpr::getIntegerCast(Op, DL.getIntPtrType(CV->getType()),
1665 false/*ZExt*/);
1666 return lowerConstant(Op, AP);
1667 }
1669 case Instruction::PtrToInt: {
1670 const DataLayout &DL = *AP.TM.getDataLayout();
1671 // Support only foldable casts to/from pointers that can be eliminated by
1672 // changing the pointer to the appropriately sized integer type.
1673 Constant *Op = CE->getOperand(0);
1674 Type *Ty = CE->getType();
1676 const MCExpr *OpExpr = lowerConstant(Op, AP);
1678 // We can emit the pointer value into this slot if the slot is an
1679 // integer slot equal to the size of the pointer.
1680 if (DL.getTypeAllocSize(Ty) == DL.getTypeAllocSize(Op->getType()))
1681 return OpExpr;
1683 // Otherwise the pointer is smaller than the resultant integer, mask off
1684 // the high bits so we are sure to get a proper truncation if the input is
1685 // a constant expr.
1686 unsigned InBits = DL.getTypeAllocSizeInBits(Op->getType());
1687 const MCExpr *MaskExpr = MCConstantExpr::Create(~0ULL >> (64-InBits), Ctx);
1688 return MCBinaryExpr::CreateAnd(OpExpr, MaskExpr, Ctx);
1689 }
1691 // The MC library also has a right-shift operator, but it isn't consistently
1692 // signed or unsigned between different targets.
1693 case Instruction::Add:
1694 case Instruction::Sub:
1695 case Instruction::Mul:
1696 case Instruction::SDiv:
1697 case Instruction::SRem:
1698 case Instruction::Shl:
1699 case Instruction::And:
1700 case Instruction::Or:
1701 case Instruction::Xor: {
1702 const MCExpr *LHS = lowerConstant(CE->getOperand(0), AP);
1703 const MCExpr *RHS = lowerConstant(CE->getOperand(1), AP);
1704 switch (CE->getOpcode()) {
1705 default: llvm_unreachable("Unknown binary operator constant cast expr");
1706 case Instruction::Add: return MCBinaryExpr::CreateAdd(LHS, RHS, Ctx);
1707 case Instruction::Sub: return MCBinaryExpr::CreateSub(LHS, RHS, Ctx);
1708 case Instruction::Mul: return MCBinaryExpr::CreateMul(LHS, RHS, Ctx);
1709 case Instruction::SDiv: return MCBinaryExpr::CreateDiv(LHS, RHS, Ctx);
1710 case Instruction::SRem: return MCBinaryExpr::CreateMod(LHS, RHS, Ctx);
1711 case Instruction::Shl: return MCBinaryExpr::CreateShl(LHS, RHS, Ctx);
1712 case Instruction::And: return MCBinaryExpr::CreateAnd(LHS, RHS, Ctx);
1713 case Instruction::Or: return MCBinaryExpr::CreateOr (LHS, RHS, Ctx);
1714 case Instruction::Xor: return MCBinaryExpr::CreateXor(LHS, RHS, Ctx);
1715 }
1716 }
1717 }
1718 }
1720 static void emitGlobalConstantImpl(const Constant *C, AsmPrinter &AP);
1722 /// isRepeatedByteSequence - Determine whether the given value is
1723 /// composed of a repeated sequence of identical bytes and return the
1724 /// byte value. If it is not a repeated sequence, return -1.
1725 static int isRepeatedByteSequence(const ConstantDataSequential *V) {
1726 StringRef Data = V->getRawDataValues();
1727 assert(!Data.empty() && "Empty aggregates should be CAZ node");
1728 char C = Data[0];
1729 for (unsigned i = 1, e = Data.size(); i != e; ++i)
1730 if (Data[i] != C) return -1;
1731 return static_cast<uint8_t>(C); // Ensure 255 is not returned as -1.
1732 }
1735 /// isRepeatedByteSequence - Determine whether the given value is
1736 /// composed of a repeated sequence of identical bytes and return the
1737 /// byte value. If it is not a repeated sequence, return -1.
1738 static int isRepeatedByteSequence(const Value *V, TargetMachine &TM) {
1740 if (const ConstantInt *CI = dyn_cast<ConstantInt>(V)) {
1741 if (CI->getBitWidth() > 64) return -1;
1743 uint64_t Size = TM.getDataLayout()->getTypeAllocSize(V->getType());
1744 uint64_t Value = CI->getZExtValue();
1746 // Make sure the constant is at least 8 bits long and has a power
1747 // of 2 bit width. This guarantees the constant bit width is
1748 // always a multiple of 8 bits, avoiding issues with padding out
1749 // to Size and other such corner cases.
1750 if (CI->getBitWidth() < 8 || !isPowerOf2_64(CI->getBitWidth())) return -1;
1752 uint8_t Byte = static_cast<uint8_t>(Value);
1754 for (unsigned i = 1; i < Size; ++i) {
1755 Value >>= 8;
1756 if (static_cast<uint8_t>(Value) != Byte) return -1;
1757 }
1758 return Byte;
1759 }
1760 if (const ConstantArray *CA = dyn_cast<ConstantArray>(V)) {
1761 // Make sure all array elements are sequences of the same repeated
1762 // byte.
1763 assert(CA->getNumOperands() != 0 && "Should be a CAZ");
1764 int Byte = isRepeatedByteSequence(CA->getOperand(0), TM);
1765 if (Byte == -1) return -1;
1767 for (unsigned i = 1, e = CA->getNumOperands(); i != e; ++i) {
1768 int ThisByte = isRepeatedByteSequence(CA->getOperand(i), TM);
1769 if (ThisByte == -1) return -1;
1770 if (Byte != ThisByte) return -1;
1771 }
1772 return Byte;
1773 }
1775 if (const ConstantDataSequential *CDS = dyn_cast<ConstantDataSequential>(V))
1776 return isRepeatedByteSequence(CDS);
1778 return -1;
1779 }
1781 static void emitGlobalConstantDataSequential(const ConstantDataSequential *CDS,
1782 AsmPrinter &AP){
1784 // See if we can aggregate this into a .fill, if so, emit it as such.
1785 int Value = isRepeatedByteSequence(CDS, AP.TM);
1786 if (Value != -1) {
1787 uint64_t Bytes = AP.TM.getDataLayout()->getTypeAllocSize(CDS->getType());
1788 // Don't emit a 1-byte object as a .fill.
1789 if (Bytes > 1)
1790 return AP.OutStreamer.EmitFill(Bytes, Value);
1791 }
1793 // If this can be emitted with .ascii/.asciz, emit it as such.
1794 if (CDS->isString())
1795 return AP.OutStreamer.EmitBytes(CDS->getAsString());
1797 // Otherwise, emit the values in successive locations.
1798 unsigned ElementByteSize = CDS->getElementByteSize();
1799 if (isa<IntegerType>(CDS->getElementType())) {
1800 for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i) {
1801 if (AP.isVerbose())
1802 AP.OutStreamer.GetCommentOS() << format("0x%" PRIx64 "\n",
1803 CDS->getElementAsInteger(i));
1804 AP.OutStreamer.EmitIntValue(CDS->getElementAsInteger(i),
1805 ElementByteSize);
1806 }
1807 } else if (ElementByteSize == 4) {
1808 // FP Constants are printed as integer constants to avoid losing
1809 // precision.
1810 assert(CDS->getElementType()->isFloatTy());
1811 for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i) {
1812 union {
1813 float F;
1814 uint32_t I;
1815 };
1817 F = CDS->getElementAsFloat(i);
1818 if (AP.isVerbose())
1819 AP.OutStreamer.GetCommentOS() << "float " << F << '\n';
1820 AP.OutStreamer.EmitIntValue(I, 4);
1821 }
1822 } else {
1823 assert(CDS->getElementType()->isDoubleTy());
1824 for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i) {
1825 union {
1826 double F;
1827 uint64_t I;
1828 };
1830 F = CDS->getElementAsDouble(i);
1831 if (AP.isVerbose())
1832 AP.OutStreamer.GetCommentOS() << "double " << F << '\n';
1833 AP.OutStreamer.EmitIntValue(I, 8);
1834 }
1835 }
1837 const DataLayout &DL = *AP.TM.getDataLayout();
1838 unsigned Size = DL.getTypeAllocSize(CDS->getType());
1839 unsigned EmittedSize = DL.getTypeAllocSize(CDS->getType()->getElementType()) *
1840 CDS->getNumElements();
1841 if (unsigned Padding = Size - EmittedSize)
1842 AP.OutStreamer.EmitZeros(Padding);
1844 }
1846 static void emitGlobalConstantArray(const ConstantArray *CA, AsmPrinter &AP) {
1847 // See if we can aggregate some values. Make sure it can be
1848 // represented as a series of bytes of the constant value.
1849 int Value = isRepeatedByteSequence(CA, AP.TM);
1851 if (Value != -1) {
1852 uint64_t Bytes = AP.TM.getDataLayout()->getTypeAllocSize(CA->getType());
1853 AP.OutStreamer.EmitFill(Bytes, Value);
1854 }
1855 else {
1856 for (unsigned i = 0, e = CA->getNumOperands(); i != e; ++i)
1857 emitGlobalConstantImpl(CA->getOperand(i), AP);
1858 }
1859 }
1861 static void emitGlobalConstantVector(const ConstantVector *CV, AsmPrinter &AP) {
1862 for (unsigned i = 0, e = CV->getType()->getNumElements(); i != e; ++i)
1863 emitGlobalConstantImpl(CV->getOperand(i), AP);
1865 const DataLayout &DL = *AP.TM.getDataLayout();
1866 unsigned Size = DL.getTypeAllocSize(CV->getType());
1867 unsigned EmittedSize = DL.getTypeAllocSize(CV->getType()->getElementType()) *
1868 CV->getType()->getNumElements();
1869 if (unsigned Padding = Size - EmittedSize)
1870 AP.OutStreamer.EmitZeros(Padding);
1871 }
1873 static void emitGlobalConstantStruct(const ConstantStruct *CS, AsmPrinter &AP) {
1874 // Print the fields in successive locations. Pad to align if needed!
1875 const DataLayout *DL = AP.TM.getDataLayout();
1876 unsigned Size = DL->getTypeAllocSize(CS->getType());
1877 const StructLayout *Layout = DL->getStructLayout(CS->getType());
1878 uint64_t SizeSoFar = 0;
1879 for (unsigned i = 0, e = CS->getNumOperands(); i != e; ++i) {
1880 const Constant *Field = CS->getOperand(i);
1882 // Check if padding is needed and insert one or more 0s.
1883 uint64_t FieldSize = DL->getTypeAllocSize(Field->getType());
1884 uint64_t PadSize = ((i == e-1 ? Size : Layout->getElementOffset(i+1))
1885 - Layout->getElementOffset(i)) - FieldSize;
1886 SizeSoFar += FieldSize + PadSize;
1888 // Now print the actual field value.
1889 emitGlobalConstantImpl(Field, AP);
1891 // Insert padding - this may include padding to increase the size of the
1892 // current field up to the ABI size (if the struct is not packed) as well
1893 // as padding to ensure that the next field starts at the right offset.
1894 AP.OutStreamer.EmitZeros(PadSize);
1895 }
1896 assert(SizeSoFar == Layout->getSizeInBytes() &&
1897 "Layout of constant struct may be incorrect!");
1898 }
1900 static void emitGlobalConstantFP(const ConstantFP *CFP, AsmPrinter &AP) {
1901 APInt API = CFP->getValueAPF().bitcastToAPInt();
1903 // First print a comment with what we think the original floating-point value
1904 // should have been.
1905 if (AP.isVerbose()) {
1906 SmallString<8> StrVal;
1907 CFP->getValueAPF().toString(StrVal);
1909 CFP->getType()->print(AP.OutStreamer.GetCommentOS());
1910 AP.OutStreamer.GetCommentOS() << ' ' << StrVal << '\n';
1911 }
1913 // Now iterate through the APInt chunks, emitting them in endian-correct
1914 // order, possibly with a smaller chunk at beginning/end (e.g. for x87 80-bit
1915 // floats).
1916 unsigned NumBytes = API.getBitWidth() / 8;
1917 unsigned TrailingBytes = NumBytes % sizeof(uint64_t);
1918 const uint64_t *p = API.getRawData();
1920 // PPC's long double has odd notions of endianness compared to how LLVM
1921 // handles it: p[0] goes first for *big* endian on PPC.
1922 if (AP.TM.getDataLayout()->isBigEndian() != CFP->getType()->isPPC_FP128Ty()) {
1923 int Chunk = API.getNumWords() - 1;
1925 if (TrailingBytes)
1926 AP.OutStreamer.EmitIntValue(p[Chunk--], TrailingBytes);
1928 for (; Chunk >= 0; --Chunk)
1929 AP.OutStreamer.EmitIntValue(p[Chunk], sizeof(uint64_t));
1930 } else {
1931 unsigned Chunk;
1932 for (Chunk = 0; Chunk < NumBytes / sizeof(uint64_t); ++Chunk)
1933 AP.OutStreamer.EmitIntValue(p[Chunk], sizeof(uint64_t));
1935 if (TrailingBytes)
1936 AP.OutStreamer.EmitIntValue(p[Chunk], TrailingBytes);
1937 }
1939 // Emit the tail padding for the long double.
1940 const DataLayout &DL = *AP.TM.getDataLayout();
1941 AP.OutStreamer.EmitZeros(DL.getTypeAllocSize(CFP->getType()) -
1942 DL.getTypeStoreSize(CFP->getType()));
1943 }
1945 static void emitGlobalConstantLargeInt(const ConstantInt *CI, AsmPrinter &AP) {
1946 const DataLayout *DL = AP.TM.getDataLayout();
1947 unsigned BitWidth = CI->getBitWidth();
1949 // Copy the value as we may massage the layout for constants whose bit width
1950 // is not a multiple of 64-bits.
1951 APInt Realigned(CI->getValue());
1952 uint64_t ExtraBits = 0;
1953 unsigned ExtraBitsSize = BitWidth & 63;
1955 if (ExtraBitsSize) {
1956 // The bit width of the data is not a multiple of 64-bits.
1957 // The extra bits are expected to be at the end of the chunk of the memory.
1958 // Little endian:
1959 // * Nothing to be done, just record the extra bits to emit.
1960 // Big endian:
1961 // * Record the extra bits to emit.
1962 // * Realign the raw data to emit the chunks of 64-bits.
1963 if (DL->isBigEndian()) {
1964 // Basically the structure of the raw data is a chunk of 64-bits cells:
1965 // 0 1 BitWidth / 64
1966 // [chunk1][chunk2] ... [chunkN].
1967 // The most significant chunk is chunkN and it should be emitted first.
1968 // However, due to the alignment issue chunkN contains useless bits.
1969 // Realign the chunks so that they contain only useless information:
1970 // ExtraBits 0 1 (BitWidth / 64) - 1
1971 // chu[nk1 chu][nk2 chu] ... [nkN-1 chunkN]
1972 ExtraBits = Realigned.getRawData()[0] &
1973 (((uint64_t)-1) >> (64 - ExtraBitsSize));
1974 Realigned = Realigned.lshr(ExtraBitsSize);
1975 } else
1976 ExtraBits = Realigned.getRawData()[BitWidth / 64];
1977 }
1979 // We don't expect assemblers to support integer data directives
1980 // for more than 64 bits, so we emit the data in at most 64-bit
1981 // quantities at a time.
1982 const uint64_t *RawData = Realigned.getRawData();
1983 for (unsigned i = 0, e = BitWidth / 64; i != e; ++i) {
1984 uint64_t Val = DL->isBigEndian() ? RawData[e - i - 1] : RawData[i];
1985 AP.OutStreamer.EmitIntValue(Val, 8);
1986 }
1988 if (ExtraBitsSize) {
1989 // Emit the extra bits after the 64-bits chunks.
1991 // Emit a directive that fills the expected size.
1992 uint64_t Size = AP.TM.getDataLayout()->getTypeAllocSize(CI->getType());
1993 Size -= (BitWidth / 64) * 8;
1994 assert(Size && Size * 8 >= ExtraBitsSize &&
1995 (ExtraBits & (((uint64_t)-1) >> (64 - ExtraBitsSize)))
1996 == ExtraBits && "Directive too small for extra bits.");
1997 AP.OutStreamer.EmitIntValue(ExtraBits, Size);
1998 }
1999 }
2001 static void emitGlobalConstantImpl(const Constant *CV, AsmPrinter &AP) {
2002 const DataLayout *DL = AP.TM.getDataLayout();
2003 uint64_t Size = DL->getTypeAllocSize(CV->getType());
2004 if (isa<ConstantAggregateZero>(CV) || isa<UndefValue>(CV))
2005 return AP.OutStreamer.EmitZeros(Size);
2007 if (const ConstantInt *CI = dyn_cast<ConstantInt>(CV)) {
2008 switch (Size) {
2009 case 1:
2010 case 2:
2011 case 4:
2012 case 8:
2013 if (AP.isVerbose())
2014 AP.OutStreamer.GetCommentOS() << format("0x%" PRIx64 "\n",
2015 CI->getZExtValue());
2016 AP.OutStreamer.EmitIntValue(CI->getZExtValue(), Size);
2017 return;
2018 default:
2019 emitGlobalConstantLargeInt(CI, AP);
2020 return;
2021 }
2022 }
2024 if (const ConstantFP *CFP = dyn_cast<ConstantFP>(CV))
2025 return emitGlobalConstantFP(CFP, AP);
2027 if (isa<ConstantPointerNull>(CV)) {
2028 AP.OutStreamer.EmitIntValue(0, Size);
2029 return;
2030 }
2032 if (const ConstantDataSequential *CDS = dyn_cast<ConstantDataSequential>(CV))
2033 return emitGlobalConstantDataSequential(CDS, AP);
2035 if (const ConstantArray *CVA = dyn_cast<ConstantArray>(CV))
2036 return emitGlobalConstantArray(CVA, AP);
2038 if (const ConstantStruct *CVS = dyn_cast<ConstantStruct>(CV))
2039 return emitGlobalConstantStruct(CVS, AP);
2041 if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(CV)) {
2042 // Look through bitcasts, which might not be able to be MCExpr'ized (e.g. of
2043 // vectors).
2044 if (CE->getOpcode() == Instruction::BitCast)
2045 return emitGlobalConstantImpl(CE->getOperand(0), AP);
2047 if (Size > 8) {
2048 // If the constant expression's size is greater than 64-bits, then we have
2049 // to emit the value in chunks. Try to constant fold the value and emit it
2050 // that way.
2051 Constant *New = ConstantFoldConstantExpression(CE, DL);
2052 if (New && New != CE)
2053 return emitGlobalConstantImpl(New, AP);
2054 }
2055 }
2057 if (const ConstantVector *V = dyn_cast<ConstantVector>(CV))
2058 return emitGlobalConstantVector(V, AP);
2060 // Otherwise, it must be a ConstantExpr. Lower it to an MCExpr, then emit it
2061 // thread the streamer with EmitValue.
2062 AP.OutStreamer.EmitValue(lowerConstant(CV, AP), Size);
2063 }
2065 /// EmitGlobalConstant - Print a general LLVM constant to the .s file.
2066 void AsmPrinter::EmitGlobalConstant(const Constant *CV) {
2067 uint64_t Size = TM.getDataLayout()->getTypeAllocSize(CV->getType());
2068 if (Size)
2069 emitGlobalConstantImpl(CV, *this);
2070 else if (MAI->hasSubsectionsViaSymbols()) {
2071 // If the global has zero size, emit a single byte so that two labels don't
2072 // look like they are at the same location.
2073 OutStreamer.EmitIntValue(0, 1);
2074 }
2075 }
2077 void AsmPrinter::EmitMachineConstantPoolValue(MachineConstantPoolValue *MCPV) {
2078 // Target doesn't support this yet!
2079 llvm_unreachable("Target does not support EmitMachineConstantPoolValue");
2080 }
2082 void AsmPrinter::printOffset(int64_t Offset, raw_ostream &OS) const {
2083 if (Offset > 0)
2084 OS << '+' << Offset;
2085 else if (Offset < 0)
2086 OS << Offset;
2087 }
2089 //===----------------------------------------------------------------------===//
2090 // Symbol Lowering Routines.
2091 //===----------------------------------------------------------------------===//
2093 /// GetTempSymbol - Return the MCSymbol corresponding to the assembler
2094 /// temporary label with the specified stem and unique ID.
2095 MCSymbol *AsmPrinter::GetTempSymbol(StringRef Name, unsigned ID) const {
2096 const DataLayout *DL = TM.getDataLayout();
2097 return OutContext.GetOrCreateSymbol(Twine(DL->getPrivateGlobalPrefix()) +
2098 Name + Twine(ID));
2099 }
2101 /// GetTempSymbol - Return an assembler temporary label with the specified
2102 /// stem.
2103 MCSymbol *AsmPrinter::GetTempSymbol(StringRef Name) const {
2104 const DataLayout *DL = TM.getDataLayout();
2105 return OutContext.GetOrCreateSymbol(Twine(DL->getPrivateGlobalPrefix())+
2106 Name);
2107 }
2110 MCSymbol *AsmPrinter::GetBlockAddressSymbol(const BlockAddress *BA) const {
2111 return MMI->getAddrLabelSymbol(BA->getBasicBlock());
2112 }
2114 MCSymbol *AsmPrinter::GetBlockAddressSymbol(const BasicBlock *BB) const {
2115 return MMI->getAddrLabelSymbol(BB);
2116 }
2118 /// GetCPISymbol - Return the symbol for the specified constant pool entry.
2119 MCSymbol *AsmPrinter::GetCPISymbol(unsigned CPID) const {
2120 const DataLayout *DL = TM.getDataLayout();
2121 return OutContext.GetOrCreateSymbol
2122 (Twine(DL->getPrivateGlobalPrefix()) + "CPI" + Twine(getFunctionNumber())
2123 + "_" + Twine(CPID));
2124 }
2126 /// GetJTISymbol - Return the symbol for the specified jump table entry.
2127 MCSymbol *AsmPrinter::GetJTISymbol(unsigned JTID, bool isLinkerPrivate) const {
2128 return MF->getJTISymbol(JTID, OutContext, isLinkerPrivate);
2129 }
2131 /// GetJTSetSymbol - Return the symbol for the specified jump table .set
2132 /// FIXME: privatize to AsmPrinter.
2133 MCSymbol *AsmPrinter::GetJTSetSymbol(unsigned UID, unsigned MBBID) const {
2134 const DataLayout *DL = TM.getDataLayout();
2135 return OutContext.GetOrCreateSymbol
2136 (Twine(DL->getPrivateGlobalPrefix()) + Twine(getFunctionNumber()) + "_" +
2137 Twine(UID) + "_set_" + Twine(MBBID));
2138 }
2140 MCSymbol *AsmPrinter::getSymbolWithGlobalValueBase(const GlobalValue *GV,
2141 StringRef Suffix) const {
2142 return getObjFileLowering().getSymbolWithGlobalValueBase(GV, Suffix, *Mang,
2143 TM);
2144 }
2146 /// GetExternalSymbolSymbol - Return the MCSymbol for the specified
2147 /// ExternalSymbol.
2148 MCSymbol *AsmPrinter::GetExternalSymbolSymbol(StringRef Sym) const {
2149 SmallString<60> NameStr;
2150 Mang->getNameWithPrefix(NameStr, Sym);
2151 return OutContext.GetOrCreateSymbol(NameStr.str());
2152 }
2156 /// PrintParentLoopComment - Print comments about parent loops of this one.
2157 static void PrintParentLoopComment(raw_ostream &OS, const MachineLoop *Loop,
2158 unsigned FunctionNumber) {
2159 if (Loop == 0) return;
2160 PrintParentLoopComment(OS, Loop->getParentLoop(), FunctionNumber);
2161 OS.indent(Loop->getLoopDepth()*2)
2162 << "Parent Loop BB" << FunctionNumber << "_"
2163 << Loop->getHeader()->getNumber()
2164 << " Depth=" << Loop->getLoopDepth() << '\n';
2165 }
2168 /// PrintChildLoopComment - Print comments about child loops within
2169 /// the loop for this basic block, with nesting.
2170 static void PrintChildLoopComment(raw_ostream &OS, const MachineLoop *Loop,
2171 unsigned FunctionNumber) {
2172 // Add child loop information
2173 for (MachineLoop::iterator CL = Loop->begin(), E = Loop->end();CL != E; ++CL){
2174 OS.indent((*CL)->getLoopDepth()*2)
2175 << "Child Loop BB" << FunctionNumber << "_"
2176 << (*CL)->getHeader()->getNumber() << " Depth " << (*CL)->getLoopDepth()
2177 << '\n';
2178 PrintChildLoopComment(OS, *CL, FunctionNumber);
2179 }
2180 }
2182 /// emitBasicBlockLoopComments - Pretty-print comments for basic blocks.
2183 static void emitBasicBlockLoopComments(const MachineBasicBlock &MBB,
2184 const MachineLoopInfo *LI,
2185 const AsmPrinter &AP) {
2186 // Add loop depth information
2187 const MachineLoop *Loop = LI->getLoopFor(&MBB);
2188 if (Loop == 0) return;
2190 MachineBasicBlock *Header = Loop->getHeader();
2191 assert(Header && "No header for loop");
2193 // If this block is not a loop header, just print out what is the loop header
2194 // and return.
2195 if (Header != &MBB) {
2196 AP.OutStreamer.AddComment(" in Loop: Header=BB" +
2197 Twine(AP.getFunctionNumber())+"_" +
2198 Twine(Loop->getHeader()->getNumber())+
2199 " Depth="+Twine(Loop->getLoopDepth()));
2200 return;
2201 }
2203 // Otherwise, it is a loop header. Print out information about child and
2204 // parent loops.
2205 raw_ostream &OS = AP.OutStreamer.GetCommentOS();
2207 PrintParentLoopComment(OS, Loop->getParentLoop(), AP.getFunctionNumber());
2209 OS << "=>";
2210 OS.indent(Loop->getLoopDepth()*2-2);
2212 OS << "This ";
2213 if (Loop->empty())
2214 OS << "Inner ";
2215 OS << "Loop Header: Depth=" + Twine(Loop->getLoopDepth()) << '\n';
2217 PrintChildLoopComment(OS, Loop, AP.getFunctionNumber());
2218 }
2221 /// EmitBasicBlockStart - This method prints the label for the specified
2222 /// MachineBasicBlock, an alignment (if present) and a comment describing
2223 /// it if appropriate.
2224 void AsmPrinter::EmitBasicBlockStart(const MachineBasicBlock *MBB) const {
2225 // Emit an alignment directive for this block, if needed.
2226 if (unsigned Align = MBB->getAlignment())
2227 EmitAlignment(Align);
2229 // If the block has its address taken, emit any labels that were used to
2230 // reference the block. It is possible that there is more than one label
2231 // here, because multiple LLVM BB's may have been RAUW'd to this block after
2232 // the references were generated.
2233 if (MBB->hasAddressTaken()) {
2234 const BasicBlock *BB = MBB->getBasicBlock();
2235 if (isVerbose())
2236 OutStreamer.AddComment("Block address taken");
2238 std::vector<MCSymbol*> Syms = MMI->getAddrLabelSymbolToEmit(BB);
2240 for (unsigned i = 0, e = Syms.size(); i != e; ++i)
2241 OutStreamer.EmitLabel(Syms[i]);
2242 }
2244 // Print some verbose block comments.
2245 if (isVerbose()) {
2246 if (const BasicBlock *BB = MBB->getBasicBlock())
2247 if (BB->hasName())
2248 OutStreamer.AddComment("%" + BB->getName());
2249 emitBasicBlockLoopComments(*MBB, LI, *this);
2250 }
2252 // Print the main label for the block.
2253 if (MBB->pred_empty() || isBlockOnlyReachableByFallthrough(MBB)) {
2254 if (isVerbose()) {
2255 // NOTE: Want this comment at start of line, don't emit with AddComment.
2256 OutStreamer.emitRawComment(" BB#" + Twine(MBB->getNumber()) + ":", false);
2257 }
2258 } else {
2259 OutStreamer.EmitLabel(MBB->getSymbol());
2260 }
2261 }
2263 void AsmPrinter::EmitVisibility(MCSymbol *Sym, unsigned Visibility,
2264 bool IsDefinition) const {
2265 MCSymbolAttr Attr = MCSA_Invalid;
2267 switch (Visibility) {
2268 default: break;
2269 case GlobalValue::HiddenVisibility:
2270 if (IsDefinition)
2271 Attr = MAI->getHiddenVisibilityAttr();
2272 else
2273 Attr = MAI->getHiddenDeclarationVisibilityAttr();
2274 break;
2275 case GlobalValue::ProtectedVisibility:
2276 Attr = MAI->getProtectedVisibilityAttr();
2277 break;
2278 }
2280 if (Attr != MCSA_Invalid)
2281 OutStreamer.EmitSymbolAttribute(Sym, Attr);
2282 }
2284 /// isBlockOnlyReachableByFallthough - Return true if the basic block has
2285 /// exactly one predecessor and the control transfer mechanism between
2286 /// the predecessor and this block is a fall-through.
2287 bool AsmPrinter::
2288 isBlockOnlyReachableByFallthrough(const MachineBasicBlock *MBB) const {
2289 // If this is a landing pad, it isn't a fall through. If it has no preds,
2290 // then nothing falls through to it.
2291 if (MBB->isLandingPad() || MBB->pred_empty())
2292 return false;
2294 // If there isn't exactly one predecessor, it can't be a fall through.
2295 MachineBasicBlock::const_pred_iterator PI = MBB->pred_begin(), PI2 = PI;
2296 ++PI2;
2297 if (PI2 != MBB->pred_end())
2298 return false;
2300 // The predecessor has to be immediately before this block.
2301 MachineBasicBlock *Pred = *PI;
2303 if (!Pred->isLayoutSuccessor(MBB))
2304 return false;
2306 // If the block is completely empty, then it definitely does fall through.
2307 if (Pred->empty())
2308 return true;
2310 // Check the terminators in the previous blocks
2311 for (MachineBasicBlock::iterator II = Pred->getFirstTerminator(),
2312 IE = Pred->end(); II != IE; ++II) {
2313 MachineInstr &MI = *II;
2315 // If it is not a simple branch, we are in a table somewhere.
2316 if (!MI.isBranch() || MI.isIndirectBranch())
2317 return false;
2319 // If we are the operands of one of the branches, this is not a fall
2320 // through. Note that targets with delay slots will usually bundle
2321 // terminators with the delay slot instruction.
2322 for (ConstMIBundleOperands OP(&MI); OP.isValid(); ++OP) {
2323 if (OP->isJTI())
2324 return false;
2325 if (OP->isMBB() && OP->getMBB() == MBB)
2326 return false;
2327 }
2328 }
2330 return true;
2331 }
2335 GCMetadataPrinter *AsmPrinter::GetOrCreateGCPrinter(GCStrategy *S) {
2336 if (!S->usesMetadata())
2337 return 0;
2339 gcp_map_type &GCMap = getGCMap(GCMetadataPrinters);
2340 gcp_map_type::iterator GCPI = GCMap.find(S);
2341 if (GCPI != GCMap.end())
2342 return GCPI->second;
2344 const char *Name = S->getName().c_str();
2346 for (GCMetadataPrinterRegistry::iterator
2347 I = GCMetadataPrinterRegistry::begin(),
2348 E = GCMetadataPrinterRegistry::end(); I != E; ++I)
2349 if (strcmp(Name, I->getName()) == 0) {
2350 GCMetadataPrinter *GMP = I->instantiate();
2351 GMP->S = S;
2352 GCMap.insert(std::make_pair(S, GMP));
2353 return GMP;
2354 }
2356 report_fatal_error("no GCMetadataPrinter registered for GC: " + Twine(Name));
2357 }
2359 /// Pin vtable to this file.
2360 AsmPrinterHandler::~AsmPrinterHandler() {}