1 //===--- CGStmt.cpp - Emit LLVM Code from Statements ----------------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // This contains code to emit Stmt nodes as LLVM code.
10 //
11 //===----------------------------------------------------------------------===//
12 
13 #include "CGDebugInfo.h"
14 #include "CodeGenFunction.h"
15 #include "CodeGenModule.h"
16 #include "TargetInfo.h"
17 #include "clang/AST/Attr.h"
18 #include "clang/AST/StmtVisitor.h"
19 #include "clang/Basic/Builtins.h"
20 #include "clang/Basic/PrettyStackTrace.h"
21 #include "clang/Basic/SourceManager.h"
22 #include "clang/Basic/TargetInfo.h"
23 #include "llvm/ADT/StringExtras.h"
24 #include "llvm/IR/DataLayout.h"
25 #include "llvm/IR/InlineAsm.h"
26 #include "llvm/IR/Intrinsics.h"
27 #include "llvm/IR/MDBuilder.h"
28 
29 using namespace clang;
30 using namespace CodeGen;
31 
32 //===----------------------------------------------------------------------===//
33 //                              Statement Emission
34 //===----------------------------------------------------------------------===//
35 
36 void CodeGenFunction::EmitStopPoint(const Stmt *S) {
37   if (CGDebugInfo *DI = getDebugInfo()) {
38     SourceLocation Loc;
39     Loc = S->getBeginLoc();
40     DI->EmitLocation(Builder, Loc);
41 
42     LastStopPoint = Loc;
43   }
44 }
45 
46 void CodeGenFunction::EmitStmt(const Stmt *S, ArrayRef<const Attr *> Attrs) {
47   assert(S && "Null statement?");
48   PGO.setCurrentStmt(S);
49 
50   // These statements have their own debug info handling.
51   if (EmitSimpleStmt(S))
52     return;
53 
54   // Check if we are generating unreachable code.
55   if (!HaveInsertPoint()) {
56     // If so, and the statement doesn't contain a label, then we do not need to
57     // generate actual code. This is safe because (1) the current point is
58     // unreachable, so we don't need to execute the code, and (2) we've already
59     // handled the statements which update internal data structures (like the
60     // local variable map) which could be used by subsequent statements.
61     if (!ContainsLabel(S)) {
62       // Verify that any decl statements were handled as simple, they may be in
63       // scope of subsequent reachable statements.
64       assert(!isa<DeclStmt>(*S) && "Unexpected DeclStmt!");
65       return;
66     }
67 
68     // Otherwise, make a new block to hold the code.
69     EnsureInsertPoint();
70   }
71 
72   // Generate a stoppoint if we are emitting debug info.
73   EmitStopPoint(S);
74 
75   // Ignore all OpenMP directives except for simd if OpenMP with Simd is
76   // enabled.
77   if (getLangOpts().OpenMP && getLangOpts().OpenMPSimd) {
78     if (const auto *D = dyn_cast<OMPExecutableDirective>(S)) {
79       EmitSimpleOMPExecutableDirective(*D);
80       return;
81     }
82   }
83 
84   switch (S->getStmtClass()) {
85   case Stmt::NoStmtClass:
86   case Stmt::CXXCatchStmtClass:
87   case Stmt::SEHExceptStmtClass:
88   case Stmt::SEHFinallyStmtClass:
89   case Stmt::MSDependentExistsStmtClass:
90     llvm_unreachable("invalid statement class to emit generically");
91   case Stmt::NullStmtClass:
92   case Stmt::CompoundStmtClass:
93   case Stmt::DeclStmtClass:
94   case Stmt::LabelStmtClass:
95   case Stmt::AttributedStmtClass:
96   case Stmt::GotoStmtClass:
97   case Stmt::BreakStmtClass:
98   case Stmt::ContinueStmtClass:
99   case Stmt::DefaultStmtClass:
100   case Stmt::CaseStmtClass:
101   case Stmt::SEHLeaveStmtClass:
102     llvm_unreachable("should have emitted these statements as simple");
103 
104 #define STMT(Type, Base)
105 #define ABSTRACT_STMT(Op)
106 #define EXPR(Type, Base) \
107   case Stmt::Type##Class:
108 #include "clang/AST/StmtNodes.inc"
109   {
110     // Remember the block we came in on.
111     llvm::BasicBlock *incoming = Builder.GetInsertBlock();
112     assert(incoming && "expression emission must have an insertion point");
113 
114     EmitIgnoredExpr(cast<Expr>(S));
115 
116     llvm::BasicBlock *outgoing = Builder.GetInsertBlock();
117     assert(outgoing && "expression emission cleared block!");
118 
119     // The expression emitters assume (reasonably!) that the insertion
120     // point is always set.  To maintain that, the call-emission code
121     // for noreturn functions has to enter a new block with no
122     // predecessors.  We want to kill that block and mark the current
123     // insertion point unreachable in the common case of a call like
124     // "exit();".  Since expression emission doesn't otherwise create
125     // blocks with no predecessors, we can just test for that.
126     // However, we must be careful not to do this to our incoming
127     // block, because *statement* emission does sometimes create
128     // reachable blocks which will have no predecessors until later in
129     // the function.  This occurs with, e.g., labels that are not
130     // reachable by fallthrough.
131     if (incoming != outgoing && outgoing->use_empty()) {
132       outgoing->eraseFromParent();
133       Builder.ClearInsertionPoint();
134     }
135     break;
136   }
137 
138   case Stmt::IndirectGotoStmtClass:
139     EmitIndirectGotoStmt(cast<IndirectGotoStmt>(*S)); break;
140 
141   case Stmt::IfStmtClass:      EmitIfStmt(cast<IfStmt>(*S));              break;
142   case Stmt::WhileStmtClass:   EmitWhileStmt(cast<WhileStmt>(*S), Attrs); break;
143   case Stmt::DoStmtClass:      EmitDoStmt(cast<DoStmt>(*S), Attrs);       break;
144   case Stmt::ForStmtClass:     EmitForStmt(cast<ForStmt>(*S), Attrs);     break;
145 
146   case Stmt::ReturnStmtClass:  EmitReturnStmt(cast<ReturnStmt>(*S));      break;
147 
148   case Stmt::SwitchStmtClass:  EmitSwitchStmt(cast<SwitchStmt>(*S));      break;
149   case Stmt::GCCAsmStmtClass:  // Intentional fall-through.
150   case Stmt::MSAsmStmtClass:   EmitAsmStmt(cast<AsmStmt>(*S));            break;
151   case Stmt::CoroutineBodyStmtClass:
152     EmitCoroutineBody(cast<CoroutineBodyStmt>(*S));
153     break;
154   case Stmt::CoreturnStmtClass:
155     EmitCoreturnStmt(cast<CoreturnStmt>(*S));
156     break;
157   case Stmt::CapturedStmtClass: {
158     const CapturedStmt *CS = cast<CapturedStmt>(S);
159     EmitCapturedStmt(*CS, CS->getCapturedRegionKind());
160     }
161     break;
162   case Stmt::ObjCAtTryStmtClass:
163     EmitObjCAtTryStmt(cast<ObjCAtTryStmt>(*S));
164     break;
165   case Stmt::ObjCAtCatchStmtClass:
166     llvm_unreachable(
167                     "@catch statements should be handled by EmitObjCAtTryStmt");
168   case Stmt::ObjCAtFinallyStmtClass:
169     llvm_unreachable(
170                   "@finally statements should be handled by EmitObjCAtTryStmt");
171   case Stmt::ObjCAtThrowStmtClass:
172     EmitObjCAtThrowStmt(cast<ObjCAtThrowStmt>(*S));
173     break;
174   case Stmt::ObjCAtSynchronizedStmtClass:
175     EmitObjCAtSynchronizedStmt(cast<ObjCAtSynchronizedStmt>(*S));
176     break;
177   case Stmt::ObjCForCollectionStmtClass:
178     EmitObjCForCollectionStmt(cast<ObjCForCollectionStmt>(*S));
179     break;
180   case Stmt::ObjCAutoreleasePoolStmtClass:
181     EmitObjCAutoreleasePoolStmt(cast<ObjCAutoreleasePoolStmt>(*S));
182     break;
183 
184   case Stmt::CXXTryStmtClass:
185     EmitCXXTryStmt(cast<CXXTryStmt>(*S));
186     break;
187   case Stmt::CXXForRangeStmtClass:
188     EmitCXXForRangeStmt(cast<CXXForRangeStmt>(*S), Attrs);
189     break;
190   case Stmt::SEHTryStmtClass:
191     EmitSEHTryStmt(cast<SEHTryStmt>(*S));
192     break;
193   case Stmt::OMPParallelDirectiveClass:
194     EmitOMPParallelDirective(cast<OMPParallelDirective>(*S));
195     break;
196   case Stmt::OMPSimdDirectiveClass:
197     EmitOMPSimdDirective(cast<OMPSimdDirective>(*S));
198     break;
199   case Stmt::OMPForDirectiveClass:
200     EmitOMPForDirective(cast<OMPForDirective>(*S));
201     break;
202   case Stmt::OMPForSimdDirectiveClass:
203     EmitOMPForSimdDirective(cast<OMPForSimdDirective>(*S));
204     break;
205   case Stmt::OMPSectionsDirectiveClass:
206     EmitOMPSectionsDirective(cast<OMPSectionsDirective>(*S));
207     break;
208   case Stmt::OMPSectionDirectiveClass:
209     EmitOMPSectionDirective(cast<OMPSectionDirective>(*S));
210     break;
211   case Stmt::OMPSingleDirectiveClass:
212     EmitOMPSingleDirective(cast<OMPSingleDirective>(*S));
213     break;
214   case Stmt::OMPMasterDirectiveClass:
215     EmitOMPMasterDirective(cast<OMPMasterDirective>(*S));
216     break;
217   case Stmt::OMPCriticalDirectiveClass:
218     EmitOMPCriticalDirective(cast<OMPCriticalDirective>(*S));
219     break;
220   case Stmt::OMPParallelForDirectiveClass:
221     EmitOMPParallelForDirective(cast<OMPParallelForDirective>(*S));
222     break;
223   case Stmt::OMPParallelForSimdDirectiveClass:
224     EmitOMPParallelForSimdDirective(cast<OMPParallelForSimdDirective>(*S));
225     break;
226   case Stmt::OMPParallelMasterDirectiveClass:
227     EmitOMPParallelMasterDirective(cast<OMPParallelMasterDirective>(*S));
228     break;
229   case Stmt::OMPParallelSectionsDirectiveClass:
230     EmitOMPParallelSectionsDirective(cast<OMPParallelSectionsDirective>(*S));
231     break;
232   case Stmt::OMPTaskDirectiveClass:
233     EmitOMPTaskDirective(cast<OMPTaskDirective>(*S));
234     break;
235   case Stmt::OMPTaskyieldDirectiveClass:
236     EmitOMPTaskyieldDirective(cast<OMPTaskyieldDirective>(*S));
237     break;
238   case Stmt::OMPBarrierDirectiveClass:
239     EmitOMPBarrierDirective(cast<OMPBarrierDirective>(*S));
240     break;
241   case Stmt::OMPTaskwaitDirectiveClass:
242     EmitOMPTaskwaitDirective(cast<OMPTaskwaitDirective>(*S));
243     break;
244   case Stmt::OMPTaskgroupDirectiveClass:
245     EmitOMPTaskgroupDirective(cast<OMPTaskgroupDirective>(*S));
246     break;
247   case Stmt::OMPFlushDirectiveClass:
248     EmitOMPFlushDirective(cast<OMPFlushDirective>(*S));
249     break;
250   case Stmt::OMPDepobjDirectiveClass:
251     EmitOMPDepobjDirective(cast<OMPDepobjDirective>(*S));
252     break;
253   case Stmt::OMPOrderedDirectiveClass:
254     EmitOMPOrderedDirective(cast<OMPOrderedDirective>(*S));
255     break;
256   case Stmt::OMPAtomicDirectiveClass:
257     EmitOMPAtomicDirective(cast<OMPAtomicDirective>(*S));
258     break;
259   case Stmt::OMPTargetDirectiveClass:
260     EmitOMPTargetDirective(cast<OMPTargetDirective>(*S));
261     break;
262   case Stmt::OMPTeamsDirectiveClass:
263     EmitOMPTeamsDirective(cast<OMPTeamsDirective>(*S));
264     break;
265   case Stmt::OMPCancellationPointDirectiveClass:
266     EmitOMPCancellationPointDirective(cast<OMPCancellationPointDirective>(*S));
267     break;
268   case Stmt::OMPCancelDirectiveClass:
269     EmitOMPCancelDirective(cast<OMPCancelDirective>(*S));
270     break;
271   case Stmt::OMPTargetDataDirectiveClass:
272     EmitOMPTargetDataDirective(cast<OMPTargetDataDirective>(*S));
273     break;
274   case Stmt::OMPTargetEnterDataDirectiveClass:
275     EmitOMPTargetEnterDataDirective(cast<OMPTargetEnterDataDirective>(*S));
276     break;
277   case Stmt::OMPTargetExitDataDirectiveClass:
278     EmitOMPTargetExitDataDirective(cast<OMPTargetExitDataDirective>(*S));
279     break;
280   case Stmt::OMPTargetParallelDirectiveClass:
281     EmitOMPTargetParallelDirective(cast<OMPTargetParallelDirective>(*S));
282     break;
283   case Stmt::OMPTargetParallelForDirectiveClass:
284     EmitOMPTargetParallelForDirective(cast<OMPTargetParallelForDirective>(*S));
285     break;
286   case Stmt::OMPTaskLoopDirectiveClass:
287     EmitOMPTaskLoopDirective(cast<OMPTaskLoopDirective>(*S));
288     break;
289   case Stmt::OMPTaskLoopSimdDirectiveClass:
290     EmitOMPTaskLoopSimdDirective(cast<OMPTaskLoopSimdDirective>(*S));
291     break;
292   case Stmt::OMPMasterTaskLoopDirectiveClass:
293     EmitOMPMasterTaskLoopDirective(cast<OMPMasterTaskLoopDirective>(*S));
294     break;
295   case Stmt::OMPMasterTaskLoopSimdDirectiveClass:
296     EmitOMPMasterTaskLoopSimdDirective(
297         cast<OMPMasterTaskLoopSimdDirective>(*S));
298     break;
299   case Stmt::OMPParallelMasterTaskLoopDirectiveClass:
300     EmitOMPParallelMasterTaskLoopDirective(
301         cast<OMPParallelMasterTaskLoopDirective>(*S));
302     break;
303   case Stmt::OMPParallelMasterTaskLoopSimdDirectiveClass:
304     EmitOMPParallelMasterTaskLoopSimdDirective(
305         cast<OMPParallelMasterTaskLoopSimdDirective>(*S));
306     break;
307   case Stmt::OMPDistributeDirectiveClass:
308     EmitOMPDistributeDirective(cast<OMPDistributeDirective>(*S));
309     break;
310   case Stmt::OMPTargetUpdateDirectiveClass:
311     EmitOMPTargetUpdateDirective(cast<OMPTargetUpdateDirective>(*S));
312     break;
313   case Stmt::OMPDistributeParallelForDirectiveClass:
314     EmitOMPDistributeParallelForDirective(
315         cast<OMPDistributeParallelForDirective>(*S));
316     break;
317   case Stmt::OMPDistributeParallelForSimdDirectiveClass:
318     EmitOMPDistributeParallelForSimdDirective(
319         cast<OMPDistributeParallelForSimdDirective>(*S));
320     break;
321   case Stmt::OMPDistributeSimdDirectiveClass:
322     EmitOMPDistributeSimdDirective(cast<OMPDistributeSimdDirective>(*S));
323     break;
324   case Stmt::OMPTargetParallelForSimdDirectiveClass:
325     EmitOMPTargetParallelForSimdDirective(
326         cast<OMPTargetParallelForSimdDirective>(*S));
327     break;
328   case Stmt::OMPTargetSimdDirectiveClass:
329     EmitOMPTargetSimdDirective(cast<OMPTargetSimdDirective>(*S));
330     break;
331   case Stmt::OMPTeamsDistributeDirectiveClass:
332     EmitOMPTeamsDistributeDirective(cast<OMPTeamsDistributeDirective>(*S));
333     break;
334   case Stmt::OMPTeamsDistributeSimdDirectiveClass:
335     EmitOMPTeamsDistributeSimdDirective(
336         cast<OMPTeamsDistributeSimdDirective>(*S));
337     break;
338   case Stmt::OMPTeamsDistributeParallelForSimdDirectiveClass:
339     EmitOMPTeamsDistributeParallelForSimdDirective(
340         cast<OMPTeamsDistributeParallelForSimdDirective>(*S));
341     break;
342   case Stmt::OMPTeamsDistributeParallelForDirectiveClass:
343     EmitOMPTeamsDistributeParallelForDirective(
344         cast<OMPTeamsDistributeParallelForDirective>(*S));
345     break;
346   case Stmt::OMPTargetTeamsDirectiveClass:
347     EmitOMPTargetTeamsDirective(cast<OMPTargetTeamsDirective>(*S));
348     break;
349   case Stmt::OMPTargetTeamsDistributeDirectiveClass:
350     EmitOMPTargetTeamsDistributeDirective(
351         cast<OMPTargetTeamsDistributeDirective>(*S));
352     break;
353   case Stmt::OMPTargetTeamsDistributeParallelForDirectiveClass:
354     EmitOMPTargetTeamsDistributeParallelForDirective(
355         cast<OMPTargetTeamsDistributeParallelForDirective>(*S));
356     break;
357   case Stmt::OMPTargetTeamsDistributeParallelForSimdDirectiveClass:
358     EmitOMPTargetTeamsDistributeParallelForSimdDirective(
359         cast<OMPTargetTeamsDistributeParallelForSimdDirective>(*S));
360     break;
361   case Stmt::OMPTargetTeamsDistributeSimdDirectiveClass:
362     EmitOMPTargetTeamsDistributeSimdDirective(
363         cast<OMPTargetTeamsDistributeSimdDirective>(*S));
364     break;
365   }
366 }
367 
368 bool CodeGenFunction::EmitSimpleStmt(const Stmt *S) {
369   switch (S->getStmtClass()) {
370   default: return false;
371   case Stmt::NullStmtClass: break;
372   case Stmt::CompoundStmtClass: EmitCompoundStmt(cast<CompoundStmt>(*S)); break;
373   case Stmt::DeclStmtClass:     EmitDeclStmt(cast<DeclStmt>(*S));         break;
374   case Stmt::LabelStmtClass:    EmitLabelStmt(cast<LabelStmt>(*S));       break;
375   case Stmt::AttributedStmtClass:
376                             EmitAttributedStmt(cast<AttributedStmt>(*S)); break;
377   case Stmt::GotoStmtClass:     EmitGotoStmt(cast<GotoStmt>(*S));         break;
378   case Stmt::BreakStmtClass:    EmitBreakStmt(cast<BreakStmt>(*S));       break;
379   case Stmt::ContinueStmtClass: EmitContinueStmt(cast<ContinueStmt>(*S)); break;
380   case Stmt::DefaultStmtClass:  EmitDefaultStmt(cast<DefaultStmt>(*S));   break;
381   case Stmt::CaseStmtClass:     EmitCaseStmt(cast<CaseStmt>(*S));         break;
382   case Stmt::SEHLeaveStmtClass: EmitSEHLeaveStmt(cast<SEHLeaveStmt>(*S)); break;
383   }
384 
385   return true;
386 }
387 
388 /// EmitCompoundStmt - Emit a compound statement {..} node.  If GetLast is true,
389 /// this captures the expression result of the last sub-statement and returns it
390 /// (for use by the statement expression extension).
391 Address CodeGenFunction::EmitCompoundStmt(const CompoundStmt &S, bool GetLast,
392                                           AggValueSlot AggSlot) {
393   PrettyStackTraceLoc CrashInfo(getContext().getSourceManager(),S.getLBracLoc(),
394                              "LLVM IR generation of compound statement ('{}')");
395 
396   // Keep track of the current cleanup stack depth, including debug scopes.
397   LexicalScope Scope(*this, S.getSourceRange());
398 
399   return EmitCompoundStmtWithoutScope(S, GetLast, AggSlot);
400 }
401 
402 Address
403 CodeGenFunction::EmitCompoundStmtWithoutScope(const CompoundStmt &S,
404                                               bool GetLast,
405                                               AggValueSlot AggSlot) {
406 
407   const Stmt *ExprResult = S.getStmtExprResult();
408   assert((!GetLast || (GetLast && ExprResult)) &&
409          "If GetLast is true then the CompoundStmt must have a StmtExprResult");
410 
411   Address RetAlloca = Address::invalid();
412 
413   for (auto *CurStmt : S.body()) {
414     if (GetLast && ExprResult == CurStmt) {
415       // We have to special case labels here.  They are statements, but when put
416       // at the end of a statement expression, they yield the value of their
417       // subexpression.  Handle this by walking through all labels we encounter,
418       // emitting them before we evaluate the subexpr.
419       // Similar issues arise for attributed statements.
420       while (!isa<Expr>(ExprResult)) {
421         if (const auto *LS = dyn_cast<LabelStmt>(ExprResult)) {
422           EmitLabel(LS->getDecl());
423           ExprResult = LS->getSubStmt();
424         } else if (const auto *AS = dyn_cast<AttributedStmt>(ExprResult)) {
425           // FIXME: Update this if we ever have attributes that affect the
426           // semantics of an expression.
427           ExprResult = AS->getSubStmt();
428         } else {
429           llvm_unreachable("unknown value statement");
430         }
431       }
432 
433       EnsureInsertPoint();
434 
435       const Expr *E = cast<Expr>(ExprResult);
436       QualType ExprTy = E->getType();
437       if (hasAggregateEvaluationKind(ExprTy)) {
438         EmitAggExpr(E, AggSlot);
439       } else {
440         // We can't return an RValue here because there might be cleanups at
441         // the end of the StmtExpr.  Because of that, we have to emit the result
442         // here into a temporary alloca.
443         RetAlloca = CreateMemTemp(ExprTy);
444         EmitAnyExprToMem(E, RetAlloca, Qualifiers(),
445                          /*IsInit*/ false);
446       }
447     } else {
448       EmitStmt(CurStmt);
449     }
450   }
451 
452   return RetAlloca;
453 }
454 
455 void CodeGenFunction::SimplifyForwardingBlocks(llvm::BasicBlock *BB) {
456   llvm::BranchInst *BI = dyn_cast<llvm::BranchInst>(BB->getTerminator());
457 
458   // If there is a cleanup stack, then we it isn't worth trying to
459   // simplify this block (we would need to remove it from the scope map
460   // and cleanup entry).
461   if (!EHStack.empty())
462     return;
463 
464   // Can only simplify direct branches.
465   if (!BI || !BI->isUnconditional())
466     return;
467 
468   // Can only simplify empty blocks.
469   if (BI->getIterator() != BB->begin())
470     return;
471 
472   BB->replaceAllUsesWith(BI->getSuccessor(0));
473   BI->eraseFromParent();
474   BB->eraseFromParent();
475 }
476 
477 void CodeGenFunction::EmitBlock(llvm::BasicBlock *BB, bool IsFinished) {
478   llvm::BasicBlock *CurBB = Builder.GetInsertBlock();
479 
480   // Fall out of the current block (if necessary).
481   EmitBranch(BB);
482 
483   if (IsFinished && BB->use_empty()) {
484     delete BB;
485     return;
486   }
487 
488   // Place the block after the current block, if possible, or else at
489   // the end of the function.
490   if (CurBB && CurBB->getParent())
491     CurFn->getBasicBlockList().insertAfter(CurBB->getIterator(), BB);
492   else
493     CurFn->getBasicBlockList().push_back(BB);
494   Builder.SetInsertPoint(BB);
495 }
496 
497 void CodeGenFunction::EmitBranch(llvm::BasicBlock *Target) {
498   // Emit a branch from the current block to the target one if this
499   // was a real block.  If this was just a fall-through block after a
500   // terminator, don't emit it.
501   llvm::BasicBlock *CurBB = Builder.GetInsertBlock();
502 
503   if (!CurBB || CurBB->getTerminator()) {
504     // If there is no insert point or the previous block is already
505     // terminated, don't touch it.
506   } else {
507     // Otherwise, create a fall-through branch.
508     Builder.CreateBr(Target);
509   }
510 
511   Builder.ClearInsertionPoint();
512 }
513 
514 void CodeGenFunction::EmitBlockAfterUses(llvm::BasicBlock *block) {
515   bool inserted = false;
516   for (llvm::User *u : block->users()) {
517     if (llvm::Instruction *insn = dyn_cast<llvm::Instruction>(u)) {
518       CurFn->getBasicBlockList().insertAfter(insn->getParent()->getIterator(),
519                                              block);
520       inserted = true;
521       break;
522     }
523   }
524 
525   if (!inserted)
526     CurFn->getBasicBlockList().push_back(block);
527 
528   Builder.SetInsertPoint(block);
529 }
530 
531 CodeGenFunction::JumpDest
532 CodeGenFunction::getJumpDestForLabel(const LabelDecl *D) {
533   JumpDest &Dest = LabelMap[D];
534   if (Dest.isValid()) return Dest;
535 
536   // Create, but don't insert, the new block.
537   Dest = JumpDest(createBasicBlock(D->getName()),
538                   EHScopeStack::stable_iterator::invalid(),
539                   NextCleanupDestIndex++);
540   return Dest;
541 }
542 
543 void CodeGenFunction::EmitLabel(const LabelDecl *D) {
544   // Add this label to the current lexical scope if we're within any
545   // normal cleanups.  Jumps "in" to this label --- when permitted by
546   // the language --- may need to be routed around such cleanups.
547   if (EHStack.hasNormalCleanups() && CurLexicalScope)
548     CurLexicalScope->addLabel(D);
549 
550   JumpDest &Dest = LabelMap[D];
551 
552   // If we didn't need a forward reference to this label, just go
553   // ahead and create a destination at the current scope.
554   if (!Dest.isValid()) {
555     Dest = getJumpDestInCurrentScope(D->getName());
556 
557   // Otherwise, we need to give this label a target depth and remove
558   // it from the branch-fixups list.
559   } else {
560     assert(!Dest.getScopeDepth().isValid() && "already emitted label!");
561     Dest.setScopeDepth(EHStack.stable_begin());
562     ResolveBranchFixups(Dest.getBlock());
563   }
564 
565   EmitBlock(Dest.getBlock());
566 
567   // Emit debug info for labels.
568   if (CGDebugInfo *DI = getDebugInfo()) {
569     if (CGM.getCodeGenOpts().hasReducedDebugInfo()) {
570       DI->setLocation(D->getLocation());
571       DI->EmitLabel(D, Builder);
572     }
573   }
574 
575   incrementProfileCounter(D->getStmt());
576 }
577 
578 /// Change the cleanup scope of the labels in this lexical scope to
579 /// match the scope of the enclosing context.
580 void CodeGenFunction::LexicalScope::rescopeLabels() {
581   assert(!Labels.empty());
582   EHScopeStack::stable_iterator innermostScope
583     = CGF.EHStack.getInnermostNormalCleanup();
584 
585   // Change the scope depth of all the labels.
586   for (SmallVectorImpl<const LabelDecl*>::const_iterator
587          i = Labels.begin(), e = Labels.end(); i != e; ++i) {
588     assert(CGF.LabelMap.count(*i));
589     JumpDest &dest = CGF.LabelMap.find(*i)->second;
590     assert(dest.getScopeDepth().isValid());
591     assert(innermostScope.encloses(dest.getScopeDepth()));
592     dest.setScopeDepth(innermostScope);
593   }
594 
595   // Reparent the labels if the new scope also has cleanups.
596   if (innermostScope != EHScopeStack::stable_end() && ParentScope) {
597     ParentScope->Labels.append(Labels.begin(), Labels.end());
598   }
599 }
600 
601 
602 void CodeGenFunction::EmitLabelStmt(const LabelStmt &S) {
603   EmitLabel(S.getDecl());
604   EmitStmt(S.getSubStmt());
605 }
606 
607 void CodeGenFunction::EmitAttributedStmt(const AttributedStmt &S) {
608   EmitStmt(S.getSubStmt(), S.getAttrs());
609 }
610 
611 void CodeGenFunction::EmitGotoStmt(const GotoStmt &S) {
612   // If this code is reachable then emit a stop point (if generating
613   // debug info). We have to do this ourselves because we are on the
614   // "simple" statement path.
615   if (HaveInsertPoint())
616     EmitStopPoint(&S);
617 
618   EmitBranchThroughCleanup(getJumpDestForLabel(S.getLabel()));
619 }
620 
621 
622 void CodeGenFunction::EmitIndirectGotoStmt(const IndirectGotoStmt &S) {
623   if (const LabelDecl *Target = S.getConstantTarget()) {
624     EmitBranchThroughCleanup(getJumpDestForLabel(Target));
625     return;
626   }
627 
628   // Ensure that we have an i8* for our PHI node.
629   llvm::Value *V = Builder.CreateBitCast(EmitScalarExpr(S.getTarget()),
630                                          Int8PtrTy, "addr");
631   llvm::BasicBlock *CurBB = Builder.GetInsertBlock();
632 
633   // Get the basic block for the indirect goto.
634   llvm::BasicBlock *IndGotoBB = GetIndirectGotoBlock();
635 
636   // The first instruction in the block has to be the PHI for the switch dest,
637   // add an entry for this branch.
638   cast<llvm::PHINode>(IndGotoBB->begin())->addIncoming(V, CurBB);
639 
640   EmitBranch(IndGotoBB);
641 }
642 
643 void CodeGenFunction::EmitIfStmt(const IfStmt &S) {
644   // C99 6.8.4.1: The first substatement is executed if the expression compares
645   // unequal to 0.  The condition must be a scalar type.
646   LexicalScope ConditionScope(*this, S.getCond()->getSourceRange());
647 
648   if (S.getInit())
649     EmitStmt(S.getInit());
650 
651   if (S.getConditionVariable())
652     EmitDecl(*S.getConditionVariable());
653 
654   // If the condition constant folds and can be elided, try to avoid emitting
655   // the condition and the dead arm of the if/else.
656   bool CondConstant;
657   if (ConstantFoldsToSimpleInteger(S.getCond(), CondConstant,
658                                    S.isConstexpr())) {
659     // Figure out which block (then or else) is executed.
660     const Stmt *Executed = S.getThen();
661     const Stmt *Skipped  = S.getElse();
662     if (!CondConstant)  // Condition false?
663       std::swap(Executed, Skipped);
664 
665     // If the skipped block has no labels in it, just emit the executed block.
666     // This avoids emitting dead code and simplifies the CFG substantially.
667     if (S.isConstexpr() || !ContainsLabel(Skipped)) {
668       if (CondConstant)
669         incrementProfileCounter(&S);
670       if (Executed) {
671         RunCleanupsScope ExecutedScope(*this);
672         EmitStmt(Executed);
673       }
674       return;
675     }
676   }
677 
678   // Otherwise, the condition did not fold, or we couldn't elide it.  Just emit
679   // the conditional branch.
680   llvm::BasicBlock *ThenBlock = createBasicBlock("if.then");
681   llvm::BasicBlock *ContBlock = createBasicBlock("if.end");
682   llvm::BasicBlock *ElseBlock = ContBlock;
683   if (S.getElse())
684     ElseBlock = createBasicBlock("if.else");
685 
686   EmitBranchOnBoolExpr(S.getCond(), ThenBlock, ElseBlock,
687                        getProfileCount(S.getThen()));
688 
689   // Emit the 'then' code.
690   EmitBlock(ThenBlock);
691   incrementProfileCounter(&S);
692   {
693     RunCleanupsScope ThenScope(*this);
694     EmitStmt(S.getThen());
695   }
696   EmitBranch(ContBlock);
697 
698   // Emit the 'else' code if present.
699   if (const Stmt *Else = S.getElse()) {
700     {
701       // There is no need to emit line number for an unconditional branch.
702       auto NL = ApplyDebugLocation::CreateEmpty(*this);
703       EmitBlock(ElseBlock);
704     }
705     {
706       RunCleanupsScope ElseScope(*this);
707       EmitStmt(Else);
708     }
709     {
710       // There is no need to emit line number for an unconditional branch.
711       auto NL = ApplyDebugLocation::CreateEmpty(*this);
712       EmitBranch(ContBlock);
713     }
714   }
715 
716   // Emit the continuation block for code after the if.
717   EmitBlock(ContBlock, true);
718 }
719 
720 void CodeGenFunction::EmitWhileStmt(const WhileStmt &S,
721                                     ArrayRef<const Attr *> WhileAttrs) {
722   // Emit the header for the loop, which will also become
723   // the continue target.
724   JumpDest LoopHeader = getJumpDestInCurrentScope("while.cond");
725   EmitBlock(LoopHeader.getBlock());
726 
727   const SourceRange &R = S.getSourceRange();
728   LoopStack.push(LoopHeader.getBlock(), CGM.getContext(), WhileAttrs,
729                  SourceLocToDebugLoc(R.getBegin()),
730                  SourceLocToDebugLoc(R.getEnd()));
731 
732   // Create an exit block for when the condition fails, which will
733   // also become the break target.
734   JumpDest LoopExit = getJumpDestInCurrentScope("while.end");
735 
736   // Store the blocks to use for break and continue.
737   BreakContinueStack.push_back(BreakContinue(LoopExit, LoopHeader));
738 
739   // C++ [stmt.while]p2:
740   //   When the condition of a while statement is a declaration, the
741   //   scope of the variable that is declared extends from its point
742   //   of declaration (3.3.2) to the end of the while statement.
743   //   [...]
744   //   The object created in a condition is destroyed and created
745   //   with each iteration of the loop.
746   RunCleanupsScope ConditionScope(*this);
747 
748   if (S.getConditionVariable())
749     EmitDecl(*S.getConditionVariable());
750 
751   // Evaluate the conditional in the while header.  C99 6.8.5.1: The
752   // evaluation of the controlling expression takes place before each
753   // execution of the loop body.
754   llvm::Value *BoolCondVal = EvaluateExprAsBool(S.getCond());
755 
756   // while(1) is common, avoid extra exit blocks.  Be sure
757   // to correctly handle break/continue though.
758   bool EmitBoolCondBranch = true;
759   if (llvm::ConstantInt *C = dyn_cast<llvm::ConstantInt>(BoolCondVal))
760     if (C->isOne())
761       EmitBoolCondBranch = false;
762 
763   // As long as the condition is true, go to the loop body.
764   llvm::BasicBlock *LoopBody = createBasicBlock("while.body");
765   if (EmitBoolCondBranch) {
766     llvm::BasicBlock *ExitBlock = LoopExit.getBlock();
767     if (ConditionScope.requiresCleanups())
768       ExitBlock = createBasicBlock("while.exit");
769     Builder.CreateCondBr(
770         BoolCondVal, LoopBody, ExitBlock,
771         createProfileWeightsForLoop(S.getCond(), getProfileCount(S.getBody())));
772 
773     if (ExitBlock != LoopExit.getBlock()) {
774       EmitBlock(ExitBlock);
775       EmitBranchThroughCleanup(LoopExit);
776     }
777   }
778 
779   // Emit the loop body.  We have to emit this in a cleanup scope
780   // because it might be a singleton DeclStmt.
781   {
782     RunCleanupsScope BodyScope(*this);
783     EmitBlock(LoopBody);
784     incrementProfileCounter(&S);
785     EmitStmt(S.getBody());
786   }
787 
788   BreakContinueStack.pop_back();
789 
790   // Immediately force cleanup.
791   ConditionScope.ForceCleanup();
792 
793   EmitStopPoint(&S);
794   // Branch to the loop header again.
795   EmitBranch(LoopHeader.getBlock());
796 
797   LoopStack.pop();
798 
799   // Emit the exit block.
800   EmitBlock(LoopExit.getBlock(), true);
801 
802   // The LoopHeader typically is just a branch if we skipped emitting
803   // a branch, try to erase it.
804   if (!EmitBoolCondBranch)
805     SimplifyForwardingBlocks(LoopHeader.getBlock());
806 }
807 
808 void CodeGenFunction::EmitDoStmt(const DoStmt &S,
809                                  ArrayRef<const Attr *> DoAttrs) {
810   JumpDest LoopExit = getJumpDestInCurrentScope("do.end");
811   JumpDest LoopCond = getJumpDestInCurrentScope("do.cond");
812 
813   uint64_t ParentCount = getCurrentProfileCount();
814 
815   // Store the blocks to use for break and continue.
816   BreakContinueStack.push_back(BreakContinue(LoopExit, LoopCond));
817 
818   // Emit the body of the loop.
819   llvm::BasicBlock *LoopBody = createBasicBlock("do.body");
820 
821   EmitBlockWithFallThrough(LoopBody, &S);
822   {
823     RunCleanupsScope BodyScope(*this);
824     EmitStmt(S.getBody());
825   }
826 
827   EmitBlock(LoopCond.getBlock());
828 
829   const SourceRange &R = S.getSourceRange();
830   LoopStack.push(LoopBody, CGM.getContext(), DoAttrs,
831                  SourceLocToDebugLoc(R.getBegin()),
832                  SourceLocToDebugLoc(R.getEnd()));
833 
834   // C99 6.8.5.2: "The evaluation of the controlling expression takes place
835   // after each execution of the loop body."
836 
837   // Evaluate the conditional in the while header.
838   // C99 6.8.5p2/p4: The first substatement is executed if the expression
839   // compares unequal to 0.  The condition must be a scalar type.
840   llvm::Value *BoolCondVal = EvaluateExprAsBool(S.getCond());
841 
842   BreakContinueStack.pop_back();
843 
844   // "do {} while (0)" is common in macros, avoid extra blocks.  Be sure
845   // to correctly handle break/continue though.
846   bool EmitBoolCondBranch = true;
847   if (llvm::ConstantInt *C = dyn_cast<llvm::ConstantInt>(BoolCondVal))
848     if (C->isZero())
849       EmitBoolCondBranch = false;
850 
851   // As long as the condition is true, iterate the loop.
852   if (EmitBoolCondBranch) {
853     uint64_t BackedgeCount = getProfileCount(S.getBody()) - ParentCount;
854     Builder.CreateCondBr(
855         BoolCondVal, LoopBody, LoopExit.getBlock(),
856         createProfileWeightsForLoop(S.getCond(), BackedgeCount));
857   }
858 
859   LoopStack.pop();
860 
861   // Emit the exit block.
862   EmitBlock(LoopExit.getBlock());
863 
864   // The DoCond block typically is just a branch if we skipped
865   // emitting a branch, try to erase it.
866   if (!EmitBoolCondBranch)
867     SimplifyForwardingBlocks(LoopCond.getBlock());
868 }
869 
870 void CodeGenFunction::EmitForStmt(const ForStmt &S,
871                                   ArrayRef<const Attr *> ForAttrs) {
872   JumpDest LoopExit = getJumpDestInCurrentScope("for.end");
873 
874   LexicalScope ForScope(*this, S.getSourceRange());
875 
876   // Evaluate the first part before the loop.
877   if (S.getInit())
878     EmitStmt(S.getInit());
879 
880   // Start the loop with a block that tests the condition.
881   // If there's an increment, the continue scope will be overwritten
882   // later.
883   JumpDest Continue = getJumpDestInCurrentScope("for.cond");
884   llvm::BasicBlock *CondBlock = Continue.getBlock();
885   EmitBlock(CondBlock);
886 
887   const SourceRange &R = S.getSourceRange();
888   LoopStack.push(CondBlock, CGM.getContext(), ForAttrs,
889                  SourceLocToDebugLoc(R.getBegin()),
890                  SourceLocToDebugLoc(R.getEnd()));
891 
892   // If the for loop doesn't have an increment we can just use the
893   // condition as the continue block.  Otherwise we'll need to create
894   // a block for it (in the current scope, i.e. in the scope of the
895   // condition), and that we will become our continue block.
896   if (S.getInc())
897     Continue = getJumpDestInCurrentScope("for.inc");
898 
899   // Store the blocks to use for break and continue.
900   BreakContinueStack.push_back(BreakContinue(LoopExit, Continue));
901 
902   // Create a cleanup scope for the condition variable cleanups.
903   LexicalScope ConditionScope(*this, S.getSourceRange());
904 
905   if (S.getCond()) {
906     // If the for statement has a condition scope, emit the local variable
907     // declaration.
908     if (S.getConditionVariable()) {
909       EmitDecl(*S.getConditionVariable());
910     }
911 
912     llvm::BasicBlock *ExitBlock = LoopExit.getBlock();
913     // If there are any cleanups between here and the loop-exit scope,
914     // create a block to stage a loop exit along.
915     if (ForScope.requiresCleanups())
916       ExitBlock = createBasicBlock("for.cond.cleanup");
917 
918     // As long as the condition is true, iterate the loop.
919     llvm::BasicBlock *ForBody = createBasicBlock("for.body");
920 
921     // C99 6.8.5p2/p4: The first substatement is executed if the expression
922     // compares unequal to 0.  The condition must be a scalar type.
923     llvm::Value *BoolCondVal = EvaluateExprAsBool(S.getCond());
924     Builder.CreateCondBr(
925         BoolCondVal, ForBody, ExitBlock,
926         createProfileWeightsForLoop(S.getCond(), getProfileCount(S.getBody())));
927 
928     if (ExitBlock != LoopExit.getBlock()) {
929       EmitBlock(ExitBlock);
930       EmitBranchThroughCleanup(LoopExit);
931     }
932 
933     EmitBlock(ForBody);
934   } else {
935     // Treat it as a non-zero constant.  Don't even create a new block for the
936     // body, just fall into it.
937   }
938   incrementProfileCounter(&S);
939 
940   {
941     // Create a separate cleanup scope for the body, in case it is not
942     // a compound statement.
943     RunCleanupsScope BodyScope(*this);
944     EmitStmt(S.getBody());
945   }
946 
947   // If there is an increment, emit it next.
948   if (S.getInc()) {
949     EmitBlock(Continue.getBlock());
950     EmitStmt(S.getInc());
951   }
952 
953   BreakContinueStack.pop_back();
954 
955   ConditionScope.ForceCleanup();
956 
957   EmitStopPoint(&S);
958   EmitBranch(CondBlock);
959 
960   ForScope.ForceCleanup();
961 
962   LoopStack.pop();
963 
964   // Emit the fall-through block.
965   EmitBlock(LoopExit.getBlock(), true);
966 }
967 
968 void
969 CodeGenFunction::EmitCXXForRangeStmt(const CXXForRangeStmt &S,
970                                      ArrayRef<const Attr *> ForAttrs) {
971   JumpDest LoopExit = getJumpDestInCurrentScope("for.end");
972 
973   LexicalScope ForScope(*this, S.getSourceRange());
974 
975   // Evaluate the first pieces before the loop.
976   if (S.getInit())
977     EmitStmt(S.getInit());
978   EmitStmt(S.getRangeStmt());
979   EmitStmt(S.getBeginStmt());
980   EmitStmt(S.getEndStmt());
981 
982   // Start the loop with a block that tests the condition.
983   // If there's an increment, the continue scope will be overwritten
984   // later.
985   llvm::BasicBlock *CondBlock = createBasicBlock("for.cond");
986   EmitBlock(CondBlock);
987 
988   const SourceRange &R = S.getSourceRange();
989   LoopStack.push(CondBlock, CGM.getContext(), ForAttrs,
990                  SourceLocToDebugLoc(R.getBegin()),
991                  SourceLocToDebugLoc(R.getEnd()));
992 
993   // If there are any cleanups between here and the loop-exit scope,
994   // create a block to stage a loop exit along.
995   llvm::BasicBlock *ExitBlock = LoopExit.getBlock();
996   if (ForScope.requiresCleanups())
997     ExitBlock = createBasicBlock("for.cond.cleanup");
998 
999   // The loop body, consisting of the specified body and the loop variable.
1000   llvm::BasicBlock *ForBody = createBasicBlock("for.body");
1001 
1002   // The body is executed if the expression, contextually converted
1003   // to bool, is true.
1004   llvm::Value *BoolCondVal = EvaluateExprAsBool(S.getCond());
1005   Builder.CreateCondBr(
1006       BoolCondVal, ForBody, ExitBlock,
1007       createProfileWeightsForLoop(S.getCond(), getProfileCount(S.getBody())));
1008 
1009   if (ExitBlock != LoopExit.getBlock()) {
1010     EmitBlock(ExitBlock);
1011     EmitBranchThroughCleanup(LoopExit);
1012   }
1013 
1014   EmitBlock(ForBody);
1015   incrementProfileCounter(&S);
1016 
1017   // Create a block for the increment. In case of a 'continue', we jump there.
1018   JumpDest Continue = getJumpDestInCurrentScope("for.inc");
1019 
1020   // Store the blocks to use for break and continue.
1021   BreakContinueStack.push_back(BreakContinue(LoopExit, Continue));
1022 
1023   {
1024     // Create a separate cleanup scope for the loop variable and body.
1025     LexicalScope BodyScope(*this, S.getSourceRange());
1026     EmitStmt(S.getLoopVarStmt());
1027     EmitStmt(S.getBody());
1028   }
1029 
1030   EmitStopPoint(&S);
1031   // If there is an increment, emit it next.
1032   EmitBlock(Continue.getBlock());
1033   EmitStmt(S.getInc());
1034 
1035   BreakContinueStack.pop_back();
1036 
1037   EmitBranch(CondBlock);
1038 
1039   ForScope.ForceCleanup();
1040 
1041   LoopStack.pop();
1042 
1043   // Emit the fall-through block.
1044   EmitBlock(LoopExit.getBlock(), true);
1045 }
1046 
1047 void CodeGenFunction::EmitReturnOfRValue(RValue RV, QualType Ty) {
1048   if (RV.isScalar()) {
1049     Builder.CreateStore(RV.getScalarVal(), ReturnValue);
1050   } else if (RV.isAggregate()) {
1051     LValue Dest = MakeAddrLValue(ReturnValue, Ty);
1052     LValue Src = MakeAddrLValue(RV.getAggregateAddress(), Ty);
1053     EmitAggregateCopy(Dest, Src, Ty, getOverlapForReturnValue());
1054   } else {
1055     EmitStoreOfComplex(RV.getComplexVal(), MakeAddrLValue(ReturnValue, Ty),
1056                        /*init*/ true);
1057   }
1058   EmitBranchThroughCleanup(ReturnBlock);
1059 }
1060 
1061 /// EmitReturnStmt - Note that due to GCC extensions, this can have an operand
1062 /// if the function returns void, or may be missing one if the function returns
1063 /// non-void.  Fun stuff :).
1064 void CodeGenFunction::EmitReturnStmt(const ReturnStmt &S) {
1065   if (requiresReturnValueCheck()) {
1066     llvm::Constant *SLoc = EmitCheckSourceLocation(S.getBeginLoc());
1067     auto *SLocPtr =
1068         new llvm::GlobalVariable(CGM.getModule(), SLoc->getType(), false,
1069                                  llvm::GlobalVariable::PrivateLinkage, SLoc);
1070     SLocPtr->setUnnamedAddr(llvm::GlobalValue::UnnamedAddr::Global);
1071     CGM.getSanitizerMetadata()->disableSanitizerForGlobal(SLocPtr);
1072     assert(ReturnLocation.isValid() && "No valid return location");
1073     Builder.CreateStore(Builder.CreateBitCast(SLocPtr, Int8PtrTy),
1074                         ReturnLocation);
1075   }
1076 
1077   // Returning from an outlined SEH helper is UB, and we already warn on it.
1078   if (IsOutlinedSEHHelper) {
1079     Builder.CreateUnreachable();
1080     Builder.ClearInsertionPoint();
1081   }
1082 
1083   // Emit the result value, even if unused, to evaluate the side effects.
1084   const Expr *RV = S.getRetValue();
1085 
1086   // Treat block literals in a return expression as if they appeared
1087   // in their own scope.  This permits a small, easily-implemented
1088   // exception to our over-conservative rules about not jumping to
1089   // statements following block literals with non-trivial cleanups.
1090   RunCleanupsScope cleanupScope(*this);
1091   if (const FullExpr *fe = dyn_cast_or_null<FullExpr>(RV)) {
1092     enterFullExpression(fe);
1093     RV = fe->getSubExpr();
1094   }
1095 
1096   // FIXME: Clean this up by using an LValue for ReturnTemp,
1097   // EmitStoreThroughLValue, and EmitAnyExpr.
1098   if (getLangOpts().ElideConstructors &&
1099       S.getNRVOCandidate() && S.getNRVOCandidate()->isNRVOVariable()) {
1100     // Apply the named return value optimization for this return statement,
1101     // which means doing nothing: the appropriate result has already been
1102     // constructed into the NRVO variable.
1103 
1104     // If there is an NRVO flag for this variable, set it to 1 into indicate
1105     // that the cleanup code should not destroy the variable.
1106     if (llvm::Value *NRVOFlag = NRVOFlags[S.getNRVOCandidate()])
1107       Builder.CreateFlagStore(Builder.getTrue(), NRVOFlag);
1108   } else if (!ReturnValue.isValid() || (RV && RV->getType()->isVoidType())) {
1109     // Make sure not to return anything, but evaluate the expression
1110     // for side effects.
1111     if (RV)
1112       EmitAnyExpr(RV);
1113   } else if (!RV) {
1114     // Do nothing (return value is left uninitialized)
1115   } else if (FnRetTy->isReferenceType()) {
1116     // If this function returns a reference, take the address of the expression
1117     // rather than the value.
1118     RValue Result = EmitReferenceBindingToExpr(RV);
1119     Builder.CreateStore(Result.getScalarVal(), ReturnValue);
1120   } else {
1121     switch (getEvaluationKind(RV->getType())) {
1122     case TEK_Scalar:
1123       Builder.CreateStore(EmitScalarExpr(RV), ReturnValue);
1124       break;
1125     case TEK_Complex:
1126       EmitComplexExprIntoLValue(RV, MakeAddrLValue(ReturnValue, RV->getType()),
1127                                 /*isInit*/ true);
1128       break;
1129     case TEK_Aggregate:
1130       EmitAggExpr(RV, AggValueSlot::forAddr(
1131                           ReturnValue, Qualifiers(),
1132                           AggValueSlot::IsDestructed,
1133                           AggValueSlot::DoesNotNeedGCBarriers,
1134                           AggValueSlot::IsNotAliased,
1135                           getOverlapForReturnValue()));
1136       break;
1137     }
1138   }
1139 
1140   ++NumReturnExprs;
1141   if (!RV || RV->isEvaluatable(getContext()))
1142     ++NumSimpleReturnExprs;
1143 
1144   cleanupScope.ForceCleanup();
1145   EmitBranchThroughCleanup(ReturnBlock);
1146 }
1147 
1148 void CodeGenFunction::EmitDeclStmt(const DeclStmt &S) {
1149   // As long as debug info is modeled with instructions, we have to ensure we
1150   // have a place to insert here and write the stop point here.
1151   if (HaveInsertPoint())
1152     EmitStopPoint(&S);
1153 
1154   for (const auto *I : S.decls())
1155     EmitDecl(*I);
1156 }
1157 
1158 void CodeGenFunction::EmitBreakStmt(const BreakStmt &S) {
1159   assert(!BreakContinueStack.empty() && "break stmt not in a loop or switch!");
1160 
1161   // If this code is reachable then emit a stop point (if generating
1162   // debug info). We have to do this ourselves because we are on the
1163   // "simple" statement path.
1164   if (HaveInsertPoint())
1165     EmitStopPoint(&S);
1166 
1167   EmitBranchThroughCleanup(BreakContinueStack.back().BreakBlock);
1168 }
1169 
1170 void CodeGenFunction::EmitContinueStmt(const ContinueStmt &S) {
1171   assert(!BreakContinueStack.empty() && "continue stmt not in a loop!");
1172 
1173   // If this code is reachable then emit a stop point (if generating
1174   // debug info). We have to do this ourselves because we are on the
1175   // "simple" statement path.
1176   if (HaveInsertPoint())
1177     EmitStopPoint(&S);
1178 
1179   EmitBranchThroughCleanup(BreakContinueStack.back().ContinueBlock);
1180 }
1181 
1182 /// EmitCaseStmtRange - If case statement range is not too big then
1183 /// add multiple cases to switch instruction, one for each value within
1184 /// the range. If range is too big then emit "if" condition check.
1185 void CodeGenFunction::EmitCaseStmtRange(const CaseStmt &S) {
1186   assert(S.getRHS() && "Expected RHS value in CaseStmt");
1187 
1188   llvm::APSInt LHS = S.getLHS()->EvaluateKnownConstInt(getContext());
1189   llvm::APSInt RHS = S.getRHS()->EvaluateKnownConstInt(getContext());
1190 
1191   // Emit the code for this case. We do this first to make sure it is
1192   // properly chained from our predecessor before generating the
1193   // switch machinery to enter this block.
1194   llvm::BasicBlock *CaseDest = createBasicBlock("sw.bb");
1195   EmitBlockWithFallThrough(CaseDest, &S);
1196   EmitStmt(S.getSubStmt());
1197 
1198   // If range is empty, do nothing.
1199   if (LHS.isSigned() ? RHS.slt(LHS) : RHS.ult(LHS))
1200     return;
1201 
1202   llvm::APInt Range = RHS - LHS;
1203   // FIXME: parameters such as this should not be hardcoded.
1204   if (Range.ult(llvm::APInt(Range.getBitWidth(), 64))) {
1205     // Range is small enough to add multiple switch instruction cases.
1206     uint64_t Total = getProfileCount(&S);
1207     unsigned NCases = Range.getZExtValue() + 1;
1208     // We only have one region counter for the entire set of cases here, so we
1209     // need to divide the weights evenly between the generated cases, ensuring
1210     // that the total weight is preserved. E.g., a weight of 5 over three cases
1211     // will be distributed as weights of 2, 2, and 1.
1212     uint64_t Weight = Total / NCases, Rem = Total % NCases;
1213     for (unsigned I = 0; I != NCases; ++I) {
1214       if (SwitchWeights)
1215         SwitchWeights->push_back(Weight + (Rem ? 1 : 0));
1216       if (Rem)
1217         Rem--;
1218       SwitchInsn->addCase(Builder.getInt(LHS), CaseDest);
1219       ++LHS;
1220     }
1221     return;
1222   }
1223 
1224   // The range is too big. Emit "if" condition into a new block,
1225   // making sure to save and restore the current insertion point.
1226   llvm::BasicBlock *RestoreBB = Builder.GetInsertBlock();
1227 
1228   // Push this test onto the chain of range checks (which terminates
1229   // in the default basic block). The switch's default will be changed
1230   // to the top of this chain after switch emission is complete.
1231   llvm::BasicBlock *FalseDest = CaseRangeBlock;
1232   CaseRangeBlock = createBasicBlock("sw.caserange");
1233 
1234   CurFn->getBasicBlockList().push_back(CaseRangeBlock);
1235   Builder.SetInsertPoint(CaseRangeBlock);
1236 
1237   // Emit range check.
1238   llvm::Value *Diff =
1239     Builder.CreateSub(SwitchInsn->getCondition(), Builder.getInt(LHS));
1240   llvm::Value *Cond =
1241     Builder.CreateICmpULE(Diff, Builder.getInt(Range), "inbounds");
1242 
1243   llvm::MDNode *Weights = nullptr;
1244   if (SwitchWeights) {
1245     uint64_t ThisCount = getProfileCount(&S);
1246     uint64_t DefaultCount = (*SwitchWeights)[0];
1247     Weights = createProfileWeights(ThisCount, DefaultCount);
1248 
1249     // Since we're chaining the switch default through each large case range, we
1250     // need to update the weight for the default, ie, the first case, to include
1251     // this case.
1252     (*SwitchWeights)[0] += ThisCount;
1253   }
1254   Builder.CreateCondBr(Cond, CaseDest, FalseDest, Weights);
1255 
1256   // Restore the appropriate insertion point.
1257   if (RestoreBB)
1258     Builder.SetInsertPoint(RestoreBB);
1259   else
1260     Builder.ClearInsertionPoint();
1261 }
1262 
1263 void CodeGenFunction::EmitCaseStmt(const CaseStmt &S) {
1264   // If there is no enclosing switch instance that we're aware of, then this
1265   // case statement and its block can be elided.  This situation only happens
1266   // when we've constant-folded the switch, are emitting the constant case,
1267   // and part of the constant case includes another case statement.  For
1268   // instance: switch (4) { case 4: do { case 5: } while (1); }
1269   if (!SwitchInsn) {
1270     EmitStmt(S.getSubStmt());
1271     return;
1272   }
1273 
1274   // Handle case ranges.
1275   if (S.getRHS()) {
1276     EmitCaseStmtRange(S);
1277     return;
1278   }
1279 
1280   llvm::ConstantInt *CaseVal =
1281     Builder.getInt(S.getLHS()->EvaluateKnownConstInt(getContext()));
1282 
1283   // If the body of the case is just a 'break', try to not emit an empty block.
1284   // If we're profiling or we're not optimizing, leave the block in for better
1285   // debug and coverage analysis.
1286   if (!CGM.getCodeGenOpts().hasProfileClangInstr() &&
1287       CGM.getCodeGenOpts().OptimizationLevel > 0 &&
1288       isa<BreakStmt>(S.getSubStmt())) {
1289     JumpDest Block = BreakContinueStack.back().BreakBlock;
1290 
1291     // Only do this optimization if there are no cleanups that need emitting.
1292     if (isObviouslyBranchWithoutCleanups(Block)) {
1293       if (SwitchWeights)
1294         SwitchWeights->push_back(getProfileCount(&S));
1295       SwitchInsn->addCase(CaseVal, Block.getBlock());
1296 
1297       // If there was a fallthrough into this case, make sure to redirect it to
1298       // the end of the switch as well.
1299       if (Builder.GetInsertBlock()) {
1300         Builder.CreateBr(Block.getBlock());
1301         Builder.ClearInsertionPoint();
1302       }
1303       return;
1304     }
1305   }
1306 
1307   llvm::BasicBlock *CaseDest = createBasicBlock("sw.bb");
1308   EmitBlockWithFallThrough(CaseDest, &S);
1309   if (SwitchWeights)
1310     SwitchWeights->push_back(getProfileCount(&S));
1311   SwitchInsn->addCase(CaseVal, CaseDest);
1312 
1313   // Recursively emitting the statement is acceptable, but is not wonderful for
1314   // code where we have many case statements nested together, i.e.:
1315   //  case 1:
1316   //    case 2:
1317   //      case 3: etc.
1318   // Handling this recursively will create a new block for each case statement
1319   // that falls through to the next case which is IR intensive.  It also causes
1320   // deep recursion which can run into stack depth limitations.  Handle
1321   // sequential non-range case statements specially.
1322   const CaseStmt *CurCase = &S;
1323   const CaseStmt *NextCase = dyn_cast<CaseStmt>(S.getSubStmt());
1324 
1325   // Otherwise, iteratively add consecutive cases to this switch stmt.
1326   while (NextCase && NextCase->getRHS() == nullptr) {
1327     CurCase = NextCase;
1328     llvm::ConstantInt *CaseVal =
1329       Builder.getInt(CurCase->getLHS()->EvaluateKnownConstInt(getContext()));
1330 
1331     if (SwitchWeights)
1332       SwitchWeights->push_back(getProfileCount(NextCase));
1333     if (CGM.getCodeGenOpts().hasProfileClangInstr()) {
1334       CaseDest = createBasicBlock("sw.bb");
1335       EmitBlockWithFallThrough(CaseDest, &S);
1336     }
1337 
1338     SwitchInsn->addCase(CaseVal, CaseDest);
1339     NextCase = dyn_cast<CaseStmt>(CurCase->getSubStmt());
1340   }
1341 
1342   // Normal default recursion for non-cases.
1343   EmitStmt(CurCase->getSubStmt());
1344 }
1345 
1346 void CodeGenFunction::EmitDefaultStmt(const DefaultStmt &S) {
1347   // If there is no enclosing switch instance that we're aware of, then this
1348   // default statement can be elided. This situation only happens when we've
1349   // constant-folded the switch.
1350   if (!SwitchInsn) {
1351     EmitStmt(S.getSubStmt());
1352     return;
1353   }
1354 
1355   llvm::BasicBlock *DefaultBlock = SwitchInsn->getDefaultDest();
1356   assert(DefaultBlock->empty() &&
1357          "EmitDefaultStmt: Default block already defined?");
1358 
1359   EmitBlockWithFallThrough(DefaultBlock, &S);
1360 
1361   EmitStmt(S.getSubStmt());
1362 }
1363 
1364 /// CollectStatementsForCase - Given the body of a 'switch' statement and a
1365 /// constant value that is being switched on, see if we can dead code eliminate
1366 /// the body of the switch to a simple series of statements to emit.  Basically,
1367 /// on a switch (5) we want to find these statements:
1368 ///    case 5:
1369 ///      printf(...);    <--
1370 ///      ++i;            <--
1371 ///      break;
1372 ///
1373 /// and add them to the ResultStmts vector.  If it is unsafe to do this
1374 /// transformation (for example, one of the elided statements contains a label
1375 /// that might be jumped to), return CSFC_Failure.  If we handled it and 'S'
1376 /// should include statements after it (e.g. the printf() line is a substmt of
1377 /// the case) then return CSFC_FallThrough.  If we handled it and found a break
1378 /// statement, then return CSFC_Success.
1379 ///
1380 /// If Case is non-null, then we are looking for the specified case, checking
1381 /// that nothing we jump over contains labels.  If Case is null, then we found
1382 /// the case and are looking for the break.
1383 ///
1384 /// If the recursive walk actually finds our Case, then we set FoundCase to
1385 /// true.
1386 ///
1387 enum CSFC_Result { CSFC_Failure, CSFC_FallThrough, CSFC_Success };
1388 static CSFC_Result CollectStatementsForCase(const Stmt *S,
1389                                             const SwitchCase *Case,
1390                                             bool &FoundCase,
1391                               SmallVectorImpl<const Stmt*> &ResultStmts) {
1392   // If this is a null statement, just succeed.
1393   if (!S)
1394     return Case ? CSFC_Success : CSFC_FallThrough;
1395 
1396   // If this is the switchcase (case 4: or default) that we're looking for, then
1397   // we're in business.  Just add the substatement.
1398   if (const SwitchCase *SC = dyn_cast<SwitchCase>(S)) {
1399     if (S == Case) {
1400       FoundCase = true;
1401       return CollectStatementsForCase(SC->getSubStmt(), nullptr, FoundCase,
1402                                       ResultStmts);
1403     }
1404 
1405     // Otherwise, this is some other case or default statement, just ignore it.
1406     return CollectStatementsForCase(SC->getSubStmt(), Case, FoundCase,
1407                                     ResultStmts);
1408   }
1409 
1410   // If we are in the live part of the code and we found our break statement,
1411   // return a success!
1412   if (!Case && isa<BreakStmt>(S))
1413     return CSFC_Success;
1414 
1415   // If this is a switch statement, then it might contain the SwitchCase, the
1416   // break, or neither.
1417   if (const CompoundStmt *CS = dyn_cast<CompoundStmt>(S)) {
1418     // Handle this as two cases: we might be looking for the SwitchCase (if so
1419     // the skipped statements must be skippable) or we might already have it.
1420     CompoundStmt::const_body_iterator I = CS->body_begin(), E = CS->body_end();
1421     bool StartedInLiveCode = FoundCase;
1422     unsigned StartSize = ResultStmts.size();
1423 
1424     // If we've not found the case yet, scan through looking for it.
1425     if (Case) {
1426       // Keep track of whether we see a skipped declaration.  The code could be
1427       // using the declaration even if it is skipped, so we can't optimize out
1428       // the decl if the kept statements might refer to it.
1429       bool HadSkippedDecl = false;
1430 
1431       // If we're looking for the case, just see if we can skip each of the
1432       // substatements.
1433       for (; Case && I != E; ++I) {
1434         HadSkippedDecl |= CodeGenFunction::mightAddDeclToScope(*I);
1435 
1436         switch (CollectStatementsForCase(*I, Case, FoundCase, ResultStmts)) {
1437         case CSFC_Failure: return CSFC_Failure;
1438         case CSFC_Success:
1439           // A successful result means that either 1) that the statement doesn't
1440           // have the case and is skippable, or 2) does contain the case value
1441           // and also contains the break to exit the switch.  In the later case,
1442           // we just verify the rest of the statements are elidable.
1443           if (FoundCase) {
1444             // If we found the case and skipped declarations, we can't do the
1445             // optimization.
1446             if (HadSkippedDecl)
1447               return CSFC_Failure;
1448 
1449             for (++I; I != E; ++I)
1450               if (CodeGenFunction::ContainsLabel(*I, true))
1451                 return CSFC_Failure;
1452             return CSFC_Success;
1453           }
1454           break;
1455         case CSFC_FallThrough:
1456           // If we have a fallthrough condition, then we must have found the
1457           // case started to include statements.  Consider the rest of the
1458           // statements in the compound statement as candidates for inclusion.
1459           assert(FoundCase && "Didn't find case but returned fallthrough?");
1460           // We recursively found Case, so we're not looking for it anymore.
1461           Case = nullptr;
1462 
1463           // If we found the case and skipped declarations, we can't do the
1464           // optimization.
1465           if (HadSkippedDecl)
1466             return CSFC_Failure;
1467           break;
1468         }
1469       }
1470 
1471       if (!FoundCase)
1472         return CSFC_Success;
1473 
1474       assert(!HadSkippedDecl && "fallthrough after skipping decl");
1475     }
1476 
1477     // If we have statements in our range, then we know that the statements are
1478     // live and need to be added to the set of statements we're tracking.
1479     bool AnyDecls = false;
1480     for (; I != E; ++I) {
1481       AnyDecls |= CodeGenFunction::mightAddDeclToScope(*I);
1482 
1483       switch (CollectStatementsForCase(*I, nullptr, FoundCase, ResultStmts)) {
1484       case CSFC_Failure: return CSFC_Failure;
1485       case CSFC_FallThrough:
1486         // A fallthrough result means that the statement was simple and just
1487         // included in ResultStmt, keep adding them afterwards.
1488         break;
1489       case CSFC_Success:
1490         // A successful result means that we found the break statement and
1491         // stopped statement inclusion.  We just ensure that any leftover stmts
1492         // are skippable and return success ourselves.
1493         for (++I; I != E; ++I)
1494           if (CodeGenFunction::ContainsLabel(*I, true))
1495             return CSFC_Failure;
1496         return CSFC_Success;
1497       }
1498     }
1499 
1500     // If we're about to fall out of a scope without hitting a 'break;', we
1501     // can't perform the optimization if there were any decls in that scope
1502     // (we'd lose their end-of-lifetime).
1503     if (AnyDecls) {
1504       // If the entire compound statement was live, there's one more thing we
1505       // can try before giving up: emit the whole thing as a single statement.
1506       // We can do that unless the statement contains a 'break;'.
1507       // FIXME: Such a break must be at the end of a construct within this one.
1508       // We could emit this by just ignoring the BreakStmts entirely.
1509       if (StartedInLiveCode && !CodeGenFunction::containsBreak(S)) {
1510         ResultStmts.resize(StartSize);
1511         ResultStmts.push_back(S);
1512       } else {
1513         return CSFC_Failure;
1514       }
1515     }
1516 
1517     return CSFC_FallThrough;
1518   }
1519 
1520   // Okay, this is some other statement that we don't handle explicitly, like a
1521   // for statement or increment etc.  If we are skipping over this statement,
1522   // just verify it doesn't have labels, which would make it invalid to elide.
1523   if (Case) {
1524     if (CodeGenFunction::ContainsLabel(S, true))
1525       return CSFC_Failure;
1526     return CSFC_Success;
1527   }
1528 
1529   // Otherwise, we want to include this statement.  Everything is cool with that
1530   // so long as it doesn't contain a break out of the switch we're in.
1531   if (CodeGenFunction::containsBreak(S)) return CSFC_Failure;
1532 
1533   // Otherwise, everything is great.  Include the statement and tell the caller
1534   // that we fall through and include the next statement as well.
1535   ResultStmts.push_back(S);
1536   return CSFC_FallThrough;
1537 }
1538 
1539 /// FindCaseStatementsForValue - Find the case statement being jumped to and
1540 /// then invoke CollectStatementsForCase to find the list of statements to emit
1541 /// for a switch on constant.  See the comment above CollectStatementsForCase
1542 /// for more details.
1543 static bool FindCaseStatementsForValue(const SwitchStmt &S,
1544                                        const llvm::APSInt &ConstantCondValue,
1545                                 SmallVectorImpl<const Stmt*> &ResultStmts,
1546                                        ASTContext &C,
1547                                        const SwitchCase *&ResultCase) {
1548   // First step, find the switch case that is being branched to.  We can do this
1549   // efficiently by scanning the SwitchCase list.
1550   const SwitchCase *Case = S.getSwitchCaseList();
1551   const DefaultStmt *DefaultCase = nullptr;
1552 
1553   for (; Case; Case = Case->getNextSwitchCase()) {
1554     // It's either a default or case.  Just remember the default statement in
1555     // case we're not jumping to any numbered cases.
1556     if (const DefaultStmt *DS = dyn_cast<DefaultStmt>(Case)) {
1557       DefaultCase = DS;
1558       continue;
1559     }
1560 
1561     // Check to see if this case is the one we're looking for.
1562     const CaseStmt *CS = cast<CaseStmt>(Case);
1563     // Don't handle case ranges yet.
1564     if (CS->getRHS()) return false;
1565 
1566     // If we found our case, remember it as 'case'.
1567     if (CS->getLHS()->EvaluateKnownConstInt(C) == ConstantCondValue)
1568       break;
1569   }
1570 
1571   // If we didn't find a matching case, we use a default if it exists, or we
1572   // elide the whole switch body!
1573   if (!Case) {
1574     // It is safe to elide the body of the switch if it doesn't contain labels
1575     // etc.  If it is safe, return successfully with an empty ResultStmts list.
1576     if (!DefaultCase)
1577       return !CodeGenFunction::ContainsLabel(&S);
1578     Case = DefaultCase;
1579   }
1580 
1581   // Ok, we know which case is being jumped to, try to collect all the
1582   // statements that follow it.  This can fail for a variety of reasons.  Also,
1583   // check to see that the recursive walk actually found our case statement.
1584   // Insane cases like this can fail to find it in the recursive walk since we
1585   // don't handle every stmt kind:
1586   // switch (4) {
1587   //   while (1) {
1588   //     case 4: ...
1589   bool FoundCase = false;
1590   ResultCase = Case;
1591   return CollectStatementsForCase(S.getBody(), Case, FoundCase,
1592                                   ResultStmts) != CSFC_Failure &&
1593          FoundCase;
1594 }
1595 
1596 void CodeGenFunction::EmitSwitchStmt(const SwitchStmt &S) {
1597   // Handle nested switch statements.
1598   llvm::SwitchInst *SavedSwitchInsn = SwitchInsn;
1599   SmallVector<uint64_t, 16> *SavedSwitchWeights = SwitchWeights;
1600   llvm::BasicBlock *SavedCRBlock = CaseRangeBlock;
1601 
1602   // See if we can constant fold the condition of the switch and therefore only
1603   // emit the live case statement (if any) of the switch.
1604   llvm::APSInt ConstantCondValue;
1605   if (ConstantFoldsToSimpleInteger(S.getCond(), ConstantCondValue)) {
1606     SmallVector<const Stmt*, 4> CaseStmts;
1607     const SwitchCase *Case = nullptr;
1608     if (FindCaseStatementsForValue(S, ConstantCondValue, CaseStmts,
1609                                    getContext(), Case)) {
1610       if (Case)
1611         incrementProfileCounter(Case);
1612       RunCleanupsScope ExecutedScope(*this);
1613 
1614       if (S.getInit())
1615         EmitStmt(S.getInit());
1616 
1617       // Emit the condition variable if needed inside the entire cleanup scope
1618       // used by this special case for constant folded switches.
1619       if (S.getConditionVariable())
1620         EmitDecl(*S.getConditionVariable());
1621 
1622       // At this point, we are no longer "within" a switch instance, so
1623       // we can temporarily enforce this to ensure that any embedded case
1624       // statements are not emitted.
1625       SwitchInsn = nullptr;
1626 
1627       // Okay, we can dead code eliminate everything except this case.  Emit the
1628       // specified series of statements and we're good.
1629       for (unsigned i = 0, e = CaseStmts.size(); i != e; ++i)
1630         EmitStmt(CaseStmts[i]);
1631       incrementProfileCounter(&S);
1632 
1633       // Now we want to restore the saved switch instance so that nested
1634       // switches continue to function properly
1635       SwitchInsn = SavedSwitchInsn;
1636 
1637       return;
1638     }
1639   }
1640 
1641   JumpDest SwitchExit = getJumpDestInCurrentScope("sw.epilog");
1642 
1643   RunCleanupsScope ConditionScope(*this);
1644 
1645   if (S.getInit())
1646     EmitStmt(S.getInit());
1647 
1648   if (S.getConditionVariable())
1649     EmitDecl(*S.getConditionVariable());
1650   llvm::Value *CondV = EmitScalarExpr(S.getCond());
1651 
1652   // Create basic block to hold stuff that comes after switch
1653   // statement. We also need to create a default block now so that
1654   // explicit case ranges tests can have a place to jump to on
1655   // failure.
1656   llvm::BasicBlock *DefaultBlock = createBasicBlock("sw.default");
1657   SwitchInsn = Builder.CreateSwitch(CondV, DefaultBlock);
1658   if (PGO.haveRegionCounts()) {
1659     // Walk the SwitchCase list to find how many there are.
1660     uint64_t DefaultCount = 0;
1661     unsigned NumCases = 0;
1662     for (const SwitchCase *Case = S.getSwitchCaseList();
1663          Case;
1664          Case = Case->getNextSwitchCase()) {
1665       if (isa<DefaultStmt>(Case))
1666         DefaultCount = getProfileCount(Case);
1667       NumCases += 1;
1668     }
1669     SwitchWeights = new SmallVector<uint64_t, 16>();
1670     SwitchWeights->reserve(NumCases);
1671     // The default needs to be first. We store the edge count, so we already
1672     // know the right weight.
1673     SwitchWeights->push_back(DefaultCount);
1674   }
1675   CaseRangeBlock = DefaultBlock;
1676 
1677   // Clear the insertion point to indicate we are in unreachable code.
1678   Builder.ClearInsertionPoint();
1679 
1680   // All break statements jump to NextBlock. If BreakContinueStack is non-empty
1681   // then reuse last ContinueBlock.
1682   JumpDest OuterContinue;
1683   if (!BreakContinueStack.empty())
1684     OuterContinue = BreakContinueStack.back().ContinueBlock;
1685 
1686   BreakContinueStack.push_back(BreakContinue(SwitchExit, OuterContinue));
1687 
1688   // Emit switch body.
1689   EmitStmt(S.getBody());
1690 
1691   BreakContinueStack.pop_back();
1692 
1693   // Update the default block in case explicit case range tests have
1694   // been chained on top.
1695   SwitchInsn->setDefaultDest(CaseRangeBlock);
1696 
1697   // If a default was never emitted:
1698   if (!DefaultBlock->getParent()) {
1699     // If we have cleanups, emit the default block so that there's a
1700     // place to jump through the cleanups from.
1701     if (ConditionScope.requiresCleanups()) {
1702       EmitBlock(DefaultBlock);
1703 
1704     // Otherwise, just forward the default block to the switch end.
1705     } else {
1706       DefaultBlock->replaceAllUsesWith(SwitchExit.getBlock());
1707       delete DefaultBlock;
1708     }
1709   }
1710 
1711   ConditionScope.ForceCleanup();
1712 
1713   // Emit continuation.
1714   EmitBlock(SwitchExit.getBlock(), true);
1715   incrementProfileCounter(&S);
1716 
1717   // If the switch has a condition wrapped by __builtin_unpredictable,
1718   // create metadata that specifies that the switch is unpredictable.
1719   // Don't bother if not optimizing because that metadata would not be used.
1720   auto *Call = dyn_cast<CallExpr>(S.getCond());
1721   if (Call && CGM.getCodeGenOpts().OptimizationLevel != 0) {
1722     auto *FD = dyn_cast_or_null<FunctionDecl>(Call->getCalleeDecl());
1723     if (FD && FD->getBuiltinID() == Builtin::BI__builtin_unpredictable) {
1724       llvm::MDBuilder MDHelper(getLLVMContext());
1725       SwitchInsn->setMetadata(llvm::LLVMContext::MD_unpredictable,
1726                               MDHelper.createUnpredictable());
1727     }
1728   }
1729 
1730   if (SwitchWeights) {
1731     assert(SwitchWeights->size() == 1 + SwitchInsn->getNumCases() &&
1732            "switch weights do not match switch cases");
1733     // If there's only one jump destination there's no sense weighting it.
1734     if (SwitchWeights->size() > 1)
1735       SwitchInsn->setMetadata(llvm::LLVMContext::MD_prof,
1736                               createProfileWeights(*SwitchWeights));
1737     delete SwitchWeights;
1738   }
1739   SwitchInsn = SavedSwitchInsn;
1740   SwitchWeights = SavedSwitchWeights;
1741   CaseRangeBlock = SavedCRBlock;
1742 }
1743 
1744 static std::string
1745 SimplifyConstraint(const char *Constraint, const TargetInfo &Target,
1746                  SmallVectorImpl<TargetInfo::ConstraintInfo> *OutCons=nullptr) {
1747   std::string Result;
1748 
1749   while (*Constraint) {
1750     switch (*Constraint) {
1751     default:
1752       Result += Target.convertConstraint(Constraint);
1753       break;
1754     // Ignore these
1755     case '*':
1756     case '?':
1757     case '!':
1758     case '=': // Will see this and the following in mult-alt constraints.
1759     case '+':
1760       break;
1761     case '#': // Ignore the rest of the constraint alternative.
1762       while (Constraint[1] && Constraint[1] != ',')
1763         Constraint++;
1764       break;
1765     case '&':
1766     case '%':
1767       Result += *Constraint;
1768       while (Constraint[1] && Constraint[1] == *Constraint)
1769         Constraint++;
1770       break;
1771     case ',':
1772       Result += "|";
1773       break;
1774     case 'g':
1775       Result += "imr";
1776       break;
1777     case '[': {
1778       assert(OutCons &&
1779              "Must pass output names to constraints with a symbolic name");
1780       unsigned Index;
1781       bool result = Target.resolveSymbolicName(Constraint, *OutCons, Index);
1782       assert(result && "Could not resolve symbolic name"); (void)result;
1783       Result += llvm::utostr(Index);
1784       break;
1785     }
1786     }
1787 
1788     Constraint++;
1789   }
1790 
1791   return Result;
1792 }
1793 
1794 /// AddVariableConstraints - Look at AsmExpr and if it is a variable declared
1795 /// as using a particular register add that as a constraint that will be used
1796 /// in this asm stmt.
1797 static std::string
1798 AddVariableConstraints(const std::string &Constraint, const Expr &AsmExpr,
1799                        const TargetInfo &Target, CodeGenModule &CGM,
1800                        const AsmStmt &Stmt, const bool EarlyClobber) {
1801   const DeclRefExpr *AsmDeclRef = dyn_cast<DeclRefExpr>(&AsmExpr);
1802   if (!AsmDeclRef)
1803     return Constraint;
1804   const ValueDecl &Value = *AsmDeclRef->getDecl();
1805   const VarDecl *Variable = dyn_cast<VarDecl>(&Value);
1806   if (!Variable)
1807     return Constraint;
1808   if (Variable->getStorageClass() != SC_Register)
1809     return Constraint;
1810   AsmLabelAttr *Attr = Variable->getAttr<AsmLabelAttr>();
1811   if (!Attr)
1812     return Constraint;
1813   StringRef Register = Attr->getLabel();
1814   assert(Target.isValidGCCRegisterName(Register));
1815   // We're using validateOutputConstraint here because we only care if
1816   // this is a register constraint.
1817   TargetInfo::ConstraintInfo Info(Constraint, "");
1818   if (Target.validateOutputConstraint(Info) &&
1819       !Info.allowsRegister()) {
1820     CGM.ErrorUnsupported(&Stmt, "__asm__");
1821     return Constraint;
1822   }
1823   // Canonicalize the register here before returning it.
1824   Register = Target.getNormalizedGCCRegisterName(Register);
1825   return (EarlyClobber ? "&{" : "{") + Register.str() + "}";
1826 }
1827 
1828 llvm::Value*
1829 CodeGenFunction::EmitAsmInputLValue(const TargetInfo::ConstraintInfo &Info,
1830                                     LValue InputValue, QualType InputType,
1831                                     std::string &ConstraintStr,
1832                                     SourceLocation Loc) {
1833   llvm::Value *Arg;
1834   if (Info.allowsRegister() || !Info.allowsMemory()) {
1835     if (CodeGenFunction::hasScalarEvaluationKind(InputType)) {
1836       Arg = EmitLoadOfLValue(InputValue, Loc).getScalarVal();
1837     } else {
1838       llvm::Type *Ty = ConvertType(InputType);
1839       uint64_t Size = CGM.getDataLayout().getTypeSizeInBits(Ty);
1840       if (Size <= 64 && llvm::isPowerOf2_64(Size)) {
1841         Ty = llvm::IntegerType::get(getLLVMContext(), Size);
1842         Ty = llvm::PointerType::getUnqual(Ty);
1843 
1844         Arg = Builder.CreateLoad(
1845             Builder.CreateBitCast(InputValue.getAddress(*this), Ty));
1846       } else {
1847         Arg = InputValue.getPointer(*this);
1848         ConstraintStr += '*';
1849       }
1850     }
1851   } else {
1852     Arg = InputValue.getPointer(*this);
1853     ConstraintStr += '*';
1854   }
1855 
1856   return Arg;
1857 }
1858 
1859 llvm::Value* CodeGenFunction::EmitAsmInput(
1860                                          const TargetInfo::ConstraintInfo &Info,
1861                                            const Expr *InputExpr,
1862                                            std::string &ConstraintStr) {
1863   // If this can't be a register or memory, i.e., has to be a constant
1864   // (immediate or symbolic), try to emit it as such.
1865   if (!Info.allowsRegister() && !Info.allowsMemory()) {
1866     if (Info.requiresImmediateConstant()) {
1867       Expr::EvalResult EVResult;
1868       InputExpr->EvaluateAsRValue(EVResult, getContext(), true);
1869 
1870       llvm::APSInt IntResult;
1871       if (EVResult.Val.toIntegralConstant(IntResult, InputExpr->getType(),
1872                                           getContext()))
1873         return llvm::ConstantInt::get(getLLVMContext(), IntResult);
1874     }
1875 
1876     Expr::EvalResult Result;
1877     if (InputExpr->EvaluateAsInt(Result, getContext()))
1878       return llvm::ConstantInt::get(getLLVMContext(), Result.Val.getInt());
1879   }
1880 
1881   if (Info.allowsRegister() || !Info.allowsMemory())
1882     if (CodeGenFunction::hasScalarEvaluationKind(InputExpr->getType()))
1883       return EmitScalarExpr(InputExpr);
1884   if (InputExpr->getStmtClass() == Expr::CXXThisExprClass)
1885     return EmitScalarExpr(InputExpr);
1886   InputExpr = InputExpr->IgnoreParenNoopCasts(getContext());
1887   LValue Dest = EmitLValue(InputExpr);
1888   return EmitAsmInputLValue(Info, Dest, InputExpr->getType(), ConstraintStr,
1889                             InputExpr->getExprLoc());
1890 }
1891 
1892 /// getAsmSrcLocInfo - Return the !srcloc metadata node to attach to an inline
1893 /// asm call instruction.  The !srcloc MDNode contains a list of constant
1894 /// integers which are the source locations of the start of each line in the
1895 /// asm.
1896 static llvm::MDNode *getAsmSrcLocInfo(const StringLiteral *Str,
1897                                       CodeGenFunction &CGF) {
1898   SmallVector<llvm::Metadata *, 8> Locs;
1899   // Add the location of the first line to the MDNode.
1900   Locs.push_back(llvm::ConstantAsMetadata::get(llvm::ConstantInt::get(
1901       CGF.Int32Ty, Str->getBeginLoc().getRawEncoding())));
1902   StringRef StrVal = Str->getString();
1903   if (!StrVal.empty()) {
1904     const SourceManager &SM = CGF.CGM.getContext().getSourceManager();
1905     const LangOptions &LangOpts = CGF.CGM.getLangOpts();
1906     unsigned StartToken = 0;
1907     unsigned ByteOffset = 0;
1908 
1909     // Add the location of the start of each subsequent line of the asm to the
1910     // MDNode.
1911     for (unsigned i = 0, e = StrVal.size() - 1; i != e; ++i) {
1912       if (StrVal[i] != '\n') continue;
1913       SourceLocation LineLoc = Str->getLocationOfByte(
1914           i + 1, SM, LangOpts, CGF.getTarget(), &StartToken, &ByteOffset);
1915       Locs.push_back(llvm::ConstantAsMetadata::get(
1916           llvm::ConstantInt::get(CGF.Int32Ty, LineLoc.getRawEncoding())));
1917     }
1918   }
1919 
1920   return llvm::MDNode::get(CGF.getLLVMContext(), Locs);
1921 }
1922 
1923 static void UpdateAsmCallInst(llvm::CallBase &Result, bool HasSideEffect,
1924                               bool ReadOnly, bool ReadNone, const AsmStmt &S,
1925                               const std::vector<llvm::Type *> &ResultRegTypes,
1926                               CodeGenFunction &CGF,
1927                               std::vector<llvm::Value *> &RegResults) {
1928   Result.addAttribute(llvm::AttributeList::FunctionIndex,
1929                       llvm::Attribute::NoUnwind);
1930   // Attach readnone and readonly attributes.
1931   if (!HasSideEffect) {
1932     if (ReadNone)
1933       Result.addAttribute(llvm::AttributeList::FunctionIndex,
1934                           llvm::Attribute::ReadNone);
1935     else if (ReadOnly)
1936       Result.addAttribute(llvm::AttributeList::FunctionIndex,
1937                           llvm::Attribute::ReadOnly);
1938   }
1939 
1940   // Slap the source location of the inline asm into a !srcloc metadata on the
1941   // call.
1942   if (const auto *gccAsmStmt = dyn_cast<GCCAsmStmt>(&S))
1943     Result.setMetadata("srcloc",
1944                        getAsmSrcLocInfo(gccAsmStmt->getAsmString(), CGF));
1945   else {
1946     // At least put the line number on MS inline asm blobs.
1947     llvm::Constant *Loc = llvm::ConstantInt::get(CGF.Int32Ty,
1948                                         S.getAsmLoc().getRawEncoding());
1949     Result.setMetadata("srcloc",
1950                        llvm::MDNode::get(CGF.getLLVMContext(),
1951                                          llvm::ConstantAsMetadata::get(Loc)));
1952   }
1953 
1954   if (CGF.getLangOpts().assumeFunctionsAreConvergent())
1955     // Conservatively, mark all inline asm blocks in CUDA or OpenCL as
1956     // convergent (meaning, they may call an intrinsically convergent op, such
1957     // as bar.sync, and so can't have certain optimizations applied around
1958     // them).
1959     Result.addAttribute(llvm::AttributeList::FunctionIndex,
1960                         llvm::Attribute::Convergent);
1961   // Extract all of the register value results from the asm.
1962   if (ResultRegTypes.size() == 1) {
1963     RegResults.push_back(&Result);
1964   } else {
1965     for (unsigned i = 0, e = ResultRegTypes.size(); i != e; ++i) {
1966       llvm::Value *Tmp = CGF.Builder.CreateExtractValue(&Result, i, "asmresult");
1967       RegResults.push_back(Tmp);
1968     }
1969   }
1970 }
1971 
1972 void CodeGenFunction::EmitAsmStmt(const AsmStmt &S) {
1973   // Assemble the final asm string.
1974   std::string AsmString = S.generateAsmString(getContext());
1975 
1976   // Get all the output and input constraints together.
1977   SmallVector<TargetInfo::ConstraintInfo, 4> OutputConstraintInfos;
1978   SmallVector<TargetInfo::ConstraintInfo, 4> InputConstraintInfos;
1979 
1980   for (unsigned i = 0, e = S.getNumOutputs(); i != e; i++) {
1981     StringRef Name;
1982     if (const GCCAsmStmt *GAS = dyn_cast<GCCAsmStmt>(&S))
1983       Name = GAS->getOutputName(i);
1984     TargetInfo::ConstraintInfo Info(S.getOutputConstraint(i), Name);
1985     bool IsValid = getTarget().validateOutputConstraint(Info); (void)IsValid;
1986     assert(IsValid && "Failed to parse output constraint");
1987     OutputConstraintInfos.push_back(Info);
1988   }
1989 
1990   for (unsigned i = 0, e = S.getNumInputs(); i != e; i++) {
1991     StringRef Name;
1992     if (const GCCAsmStmt *GAS = dyn_cast<GCCAsmStmt>(&S))
1993       Name = GAS->getInputName(i);
1994     TargetInfo::ConstraintInfo Info(S.getInputConstraint(i), Name);
1995     bool IsValid =
1996       getTarget().validateInputConstraint(OutputConstraintInfos, Info);
1997     assert(IsValid && "Failed to parse input constraint"); (void)IsValid;
1998     InputConstraintInfos.push_back(Info);
1999   }
2000 
2001   std::string Constraints;
2002 
2003   std::vector<LValue> ResultRegDests;
2004   std::vector<QualType> ResultRegQualTys;
2005   std::vector<llvm::Type *> ResultRegTypes;
2006   std::vector<llvm::Type *> ResultTruncRegTypes;
2007   std::vector<llvm::Type *> ArgTypes;
2008   std::vector<llvm::Value*> Args;
2009   llvm::BitVector ResultTypeRequiresCast;
2010 
2011   // Keep track of inout constraints.
2012   std::string InOutConstraints;
2013   std::vector<llvm::Value*> InOutArgs;
2014   std::vector<llvm::Type*> InOutArgTypes;
2015 
2016   // Keep track of out constraints for tied input operand.
2017   std::vector<std::string> OutputConstraints;
2018 
2019   // An inline asm can be marked readonly if it meets the following conditions:
2020   //  - it doesn't have any sideeffects
2021   //  - it doesn't clobber memory
2022   //  - it doesn't return a value by-reference
2023   // It can be marked readnone if it doesn't have any input memory constraints
2024   // in addition to meeting the conditions listed above.
2025   bool ReadOnly = true, ReadNone = true;
2026 
2027   for (unsigned i = 0, e = S.getNumOutputs(); i != e; i++) {
2028     TargetInfo::ConstraintInfo &Info = OutputConstraintInfos[i];
2029 
2030     // Simplify the output constraint.
2031     std::string OutputConstraint(S.getOutputConstraint(i));
2032     OutputConstraint = SimplifyConstraint(OutputConstraint.c_str() + 1,
2033                                           getTarget(), &OutputConstraintInfos);
2034 
2035     const Expr *OutExpr = S.getOutputExpr(i);
2036     OutExpr = OutExpr->IgnoreParenNoopCasts(getContext());
2037 
2038     OutputConstraint = AddVariableConstraints(OutputConstraint, *OutExpr,
2039                                               getTarget(), CGM, S,
2040                                               Info.earlyClobber());
2041     OutputConstraints.push_back(OutputConstraint);
2042     LValue Dest = EmitLValue(OutExpr);
2043     if (!Constraints.empty())
2044       Constraints += ',';
2045 
2046     // If this is a register output, then make the inline asm return it
2047     // by-value.  If this is a memory result, return the value by-reference.
2048     bool isScalarizableAggregate =
2049         hasAggregateEvaluationKind(OutExpr->getType());
2050     if (!Info.allowsMemory() && (hasScalarEvaluationKind(OutExpr->getType()) ||
2051                                  isScalarizableAggregate)) {
2052       Constraints += "=" + OutputConstraint;
2053       ResultRegQualTys.push_back(OutExpr->getType());
2054       ResultRegDests.push_back(Dest);
2055       ResultTruncRegTypes.push_back(ConvertTypeForMem(OutExpr->getType()));
2056       if (Info.allowsRegister() && isScalarizableAggregate) {
2057         ResultTypeRequiresCast.push_back(true);
2058         unsigned Size = getContext().getTypeSize(OutExpr->getType());
2059         llvm::Type *ConvTy = llvm::IntegerType::get(getLLVMContext(), Size);
2060         ResultRegTypes.push_back(ConvTy);
2061       } else {
2062         ResultTypeRequiresCast.push_back(false);
2063         ResultRegTypes.push_back(ResultTruncRegTypes.back());
2064       }
2065       // If this output is tied to an input, and if the input is larger, then
2066       // we need to set the actual result type of the inline asm node to be the
2067       // same as the input type.
2068       if (Info.hasMatchingInput()) {
2069         unsigned InputNo;
2070         for (InputNo = 0; InputNo != S.getNumInputs(); ++InputNo) {
2071           TargetInfo::ConstraintInfo &Input = InputConstraintInfos[InputNo];
2072           if (Input.hasTiedOperand() && Input.getTiedOperand() == i)
2073             break;
2074         }
2075         assert(InputNo != S.getNumInputs() && "Didn't find matching input!");
2076 
2077         QualType InputTy = S.getInputExpr(InputNo)->getType();
2078         QualType OutputType = OutExpr->getType();
2079 
2080         uint64_t InputSize = getContext().getTypeSize(InputTy);
2081         if (getContext().getTypeSize(OutputType) < InputSize) {
2082           // Form the asm to return the value as a larger integer or fp type.
2083           ResultRegTypes.back() = ConvertType(InputTy);
2084         }
2085       }
2086       if (llvm::Type* AdjTy =
2087             getTargetHooks().adjustInlineAsmType(*this, OutputConstraint,
2088                                                  ResultRegTypes.back()))
2089         ResultRegTypes.back() = AdjTy;
2090       else {
2091         CGM.getDiags().Report(S.getAsmLoc(),
2092                               diag::err_asm_invalid_type_in_input)
2093             << OutExpr->getType() << OutputConstraint;
2094       }
2095 
2096       // Update largest vector width for any vector types.
2097       if (auto *VT = dyn_cast<llvm::VectorType>(ResultRegTypes.back()))
2098         LargestVectorWidth =
2099             std::max((uint64_t)LargestVectorWidth,
2100                      VT->getPrimitiveSizeInBits().getKnownMinSize());
2101     } else {
2102       ArgTypes.push_back(Dest.getAddress(*this).getType());
2103       Args.push_back(Dest.getPointer(*this));
2104       Constraints += "=*";
2105       Constraints += OutputConstraint;
2106       ReadOnly = ReadNone = false;
2107     }
2108 
2109     if (Info.isReadWrite()) {
2110       InOutConstraints += ',';
2111 
2112       const Expr *InputExpr = S.getOutputExpr(i);
2113       llvm::Value *Arg = EmitAsmInputLValue(Info, Dest, InputExpr->getType(),
2114                                             InOutConstraints,
2115                                             InputExpr->getExprLoc());
2116 
2117       if (llvm::Type* AdjTy =
2118           getTargetHooks().adjustInlineAsmType(*this, OutputConstraint,
2119                                                Arg->getType()))
2120         Arg = Builder.CreateBitCast(Arg, AdjTy);
2121 
2122       // Update largest vector width for any vector types.
2123       if (auto *VT = dyn_cast<llvm::VectorType>(Arg->getType()))
2124         LargestVectorWidth =
2125             std::max((uint64_t)LargestVectorWidth,
2126                      VT->getPrimitiveSizeInBits().getKnownMinSize());
2127       if (Info.allowsRegister())
2128         InOutConstraints += llvm::utostr(i);
2129       else
2130         InOutConstraints += OutputConstraint;
2131 
2132       InOutArgTypes.push_back(Arg->getType());
2133       InOutArgs.push_back(Arg);
2134     }
2135   }
2136 
2137   // If this is a Microsoft-style asm blob, store the return registers (EAX:EDX)
2138   // to the return value slot. Only do this when returning in registers.
2139   if (isa<MSAsmStmt>(&S)) {
2140     const ABIArgInfo &RetAI = CurFnInfo->getReturnInfo();
2141     if (RetAI.isDirect() || RetAI.isExtend()) {
2142       // Make a fake lvalue for the return value slot.
2143       LValue ReturnSlot = MakeAddrLValue(ReturnValue, FnRetTy);
2144       CGM.getTargetCodeGenInfo().addReturnRegisterOutputs(
2145           *this, ReturnSlot, Constraints, ResultRegTypes, ResultTruncRegTypes,
2146           ResultRegDests, AsmString, S.getNumOutputs());
2147       SawAsmBlock = true;
2148     }
2149   }
2150 
2151   for (unsigned i = 0, e = S.getNumInputs(); i != e; i++) {
2152     const Expr *InputExpr = S.getInputExpr(i);
2153 
2154     TargetInfo::ConstraintInfo &Info = InputConstraintInfos[i];
2155 
2156     if (Info.allowsMemory())
2157       ReadNone = false;
2158 
2159     if (!Constraints.empty())
2160       Constraints += ',';
2161 
2162     // Simplify the input constraint.
2163     std::string InputConstraint(S.getInputConstraint(i));
2164     InputConstraint = SimplifyConstraint(InputConstraint.c_str(), getTarget(),
2165                                          &OutputConstraintInfos);
2166 
2167     InputConstraint = AddVariableConstraints(
2168         InputConstraint, *InputExpr->IgnoreParenNoopCasts(getContext()),
2169         getTarget(), CGM, S, false /* No EarlyClobber */);
2170 
2171     std::string ReplaceConstraint (InputConstraint);
2172     llvm::Value *Arg = EmitAsmInput(Info, InputExpr, Constraints);
2173 
2174     // If this input argument is tied to a larger output result, extend the
2175     // input to be the same size as the output.  The LLVM backend wants to see
2176     // the input and output of a matching constraint be the same size.  Note
2177     // that GCC does not define what the top bits are here.  We use zext because
2178     // that is usually cheaper, but LLVM IR should really get an anyext someday.
2179     if (Info.hasTiedOperand()) {
2180       unsigned Output = Info.getTiedOperand();
2181       QualType OutputType = S.getOutputExpr(Output)->getType();
2182       QualType InputTy = InputExpr->getType();
2183 
2184       if (getContext().getTypeSize(OutputType) >
2185           getContext().getTypeSize(InputTy)) {
2186         // Use ptrtoint as appropriate so that we can do our extension.
2187         if (isa<llvm::PointerType>(Arg->getType()))
2188           Arg = Builder.CreatePtrToInt(Arg, IntPtrTy);
2189         llvm::Type *OutputTy = ConvertType(OutputType);
2190         if (isa<llvm::IntegerType>(OutputTy))
2191           Arg = Builder.CreateZExt(Arg, OutputTy);
2192         else if (isa<llvm::PointerType>(OutputTy))
2193           Arg = Builder.CreateZExt(Arg, IntPtrTy);
2194         else {
2195           assert(OutputTy->isFloatingPointTy() && "Unexpected output type");
2196           Arg = Builder.CreateFPExt(Arg, OutputTy);
2197         }
2198       }
2199       // Deal with the tied operands' constraint code in adjustInlineAsmType.
2200       ReplaceConstraint = OutputConstraints[Output];
2201     }
2202     if (llvm::Type* AdjTy =
2203           getTargetHooks().adjustInlineAsmType(*this, ReplaceConstraint,
2204                                                    Arg->getType()))
2205       Arg = Builder.CreateBitCast(Arg, AdjTy);
2206     else
2207       CGM.getDiags().Report(S.getAsmLoc(), diag::err_asm_invalid_type_in_input)
2208           << InputExpr->getType() << InputConstraint;
2209 
2210     // Update largest vector width for any vector types.
2211     if (auto *VT = dyn_cast<llvm::VectorType>(Arg->getType()))
2212       LargestVectorWidth =
2213           std::max((uint64_t)LargestVectorWidth,
2214                    VT->getPrimitiveSizeInBits().getKnownMinSize());
2215 
2216     ArgTypes.push_back(Arg->getType());
2217     Args.push_back(Arg);
2218     Constraints += InputConstraint;
2219   }
2220 
2221   // Labels
2222   SmallVector<llvm::BasicBlock *, 16> Transfer;
2223   llvm::BasicBlock *Fallthrough = nullptr;
2224   bool IsGCCAsmGoto = false;
2225   if (const auto *GS =  dyn_cast<GCCAsmStmt>(&S)) {
2226     IsGCCAsmGoto = GS->isAsmGoto();
2227     if (IsGCCAsmGoto) {
2228       for (const auto *E : GS->labels()) {
2229         JumpDest Dest = getJumpDestForLabel(E->getLabel());
2230         Transfer.push_back(Dest.getBlock());
2231         llvm::BlockAddress *BA =
2232             llvm::BlockAddress::get(CurFn, Dest.getBlock());
2233         Args.push_back(BA);
2234         ArgTypes.push_back(BA->getType());
2235         if (!Constraints.empty())
2236           Constraints += ',';
2237         Constraints += 'X';
2238       }
2239       Fallthrough = createBasicBlock("asm.fallthrough");
2240     }
2241   }
2242 
2243   // Append the "input" part of inout constraints last.
2244   for (unsigned i = 0, e = InOutArgs.size(); i != e; i++) {
2245     ArgTypes.push_back(InOutArgTypes[i]);
2246     Args.push_back(InOutArgs[i]);
2247   }
2248   Constraints += InOutConstraints;
2249 
2250   // Clobbers
2251   for (unsigned i = 0, e = S.getNumClobbers(); i != e; i++) {
2252     StringRef Clobber = S.getClobber(i);
2253 
2254     if (Clobber == "memory")
2255       ReadOnly = ReadNone = false;
2256     else if (Clobber != "cc") {
2257       Clobber = getTarget().getNormalizedGCCRegisterName(Clobber);
2258       if (CGM.getCodeGenOpts().StackClashProtector &&
2259           getTarget().isSPRegName(Clobber)) {
2260         CGM.getDiags().Report(S.getAsmLoc(),
2261                               diag::warn_stack_clash_protection_inline_asm);
2262       }
2263     }
2264 
2265     if (!Constraints.empty())
2266       Constraints += ',';
2267 
2268     Constraints += "~{";
2269     Constraints += Clobber;
2270     Constraints += '}';
2271   }
2272 
2273   // Add machine specific clobbers
2274   std::string MachineClobbers = getTarget().getClobbers();
2275   if (!MachineClobbers.empty()) {
2276     if (!Constraints.empty())
2277       Constraints += ',';
2278     Constraints += MachineClobbers;
2279   }
2280 
2281   llvm::Type *ResultType;
2282   if (ResultRegTypes.empty())
2283     ResultType = VoidTy;
2284   else if (ResultRegTypes.size() == 1)
2285     ResultType = ResultRegTypes[0];
2286   else
2287     ResultType = llvm::StructType::get(getLLVMContext(), ResultRegTypes);
2288 
2289   llvm::FunctionType *FTy =
2290     llvm::FunctionType::get(ResultType, ArgTypes, false);
2291 
2292   bool HasSideEffect = S.isVolatile() || S.getNumOutputs() == 0;
2293   llvm::InlineAsm::AsmDialect AsmDialect = isa<MSAsmStmt>(&S) ?
2294     llvm::InlineAsm::AD_Intel : llvm::InlineAsm::AD_ATT;
2295   llvm::InlineAsm *IA =
2296     llvm::InlineAsm::get(FTy, AsmString, Constraints, HasSideEffect,
2297                          /* IsAlignStack */ false, AsmDialect);
2298   std::vector<llvm::Value*> RegResults;
2299   if (IsGCCAsmGoto) {
2300     llvm::CallBrInst *Result =
2301         Builder.CreateCallBr(IA, Fallthrough, Transfer, Args);
2302     EmitBlock(Fallthrough);
2303     UpdateAsmCallInst(cast<llvm::CallBase>(*Result), HasSideEffect, ReadOnly,
2304                       ReadNone, S, ResultRegTypes, *this, RegResults);
2305   } else {
2306     llvm::CallInst *Result =
2307         Builder.CreateCall(IA, Args, getBundlesForFunclet(IA));
2308     UpdateAsmCallInst(cast<llvm::CallBase>(*Result), HasSideEffect, ReadOnly,
2309                       ReadNone, S, ResultRegTypes, *this, RegResults);
2310   }
2311 
2312   assert(RegResults.size() == ResultRegTypes.size());
2313   assert(RegResults.size() == ResultTruncRegTypes.size());
2314   assert(RegResults.size() == ResultRegDests.size());
2315   // ResultRegDests can be also populated by addReturnRegisterOutputs() above,
2316   // in which case its size may grow.
2317   assert(ResultTypeRequiresCast.size() <= ResultRegDests.size());
2318   for (unsigned i = 0, e = RegResults.size(); i != e; ++i) {
2319     llvm::Value *Tmp = RegResults[i];
2320 
2321     // If the result type of the LLVM IR asm doesn't match the result type of
2322     // the expression, do the conversion.
2323     if (ResultRegTypes[i] != ResultTruncRegTypes[i]) {
2324       llvm::Type *TruncTy = ResultTruncRegTypes[i];
2325 
2326       // Truncate the integer result to the right size, note that TruncTy can be
2327       // a pointer.
2328       if (TruncTy->isFloatingPointTy())
2329         Tmp = Builder.CreateFPTrunc(Tmp, TruncTy);
2330       else if (TruncTy->isPointerTy() && Tmp->getType()->isIntegerTy()) {
2331         uint64_t ResSize = CGM.getDataLayout().getTypeSizeInBits(TruncTy);
2332         Tmp = Builder.CreateTrunc(Tmp,
2333                    llvm::IntegerType::get(getLLVMContext(), (unsigned)ResSize));
2334         Tmp = Builder.CreateIntToPtr(Tmp, TruncTy);
2335       } else if (Tmp->getType()->isPointerTy() && TruncTy->isIntegerTy()) {
2336         uint64_t TmpSize =CGM.getDataLayout().getTypeSizeInBits(Tmp->getType());
2337         Tmp = Builder.CreatePtrToInt(Tmp,
2338                    llvm::IntegerType::get(getLLVMContext(), (unsigned)TmpSize));
2339         Tmp = Builder.CreateTrunc(Tmp, TruncTy);
2340       } else if (TruncTy->isIntegerTy()) {
2341         Tmp = Builder.CreateZExtOrTrunc(Tmp, TruncTy);
2342       } else if (TruncTy->isVectorTy()) {
2343         Tmp = Builder.CreateBitCast(Tmp, TruncTy);
2344       }
2345     }
2346 
2347     LValue Dest = ResultRegDests[i];
2348     // ResultTypeRequiresCast elements correspond to the first
2349     // ResultTypeRequiresCast.size() elements of RegResults.
2350     if ((i < ResultTypeRequiresCast.size()) && ResultTypeRequiresCast[i]) {
2351       unsigned Size = getContext().getTypeSize(ResultRegQualTys[i]);
2352       Address A = Builder.CreateBitCast(Dest.getAddress(*this),
2353                                         ResultRegTypes[i]->getPointerTo());
2354       QualType Ty = getContext().getIntTypeForBitwidth(Size, /*Signed*/ false);
2355       if (Ty.isNull()) {
2356         const Expr *OutExpr = S.getOutputExpr(i);
2357         CGM.Error(
2358             OutExpr->getExprLoc(),
2359             "impossible constraint in asm: can't store value into a register");
2360         return;
2361       }
2362       Dest = MakeAddrLValue(A, Ty);
2363     }
2364     EmitStoreThroughLValue(RValue::get(Tmp), Dest);
2365   }
2366 }
2367 
2368 LValue CodeGenFunction::InitCapturedStruct(const CapturedStmt &S) {
2369   const RecordDecl *RD = S.getCapturedRecordDecl();
2370   QualType RecordTy = getContext().getRecordType(RD);
2371 
2372   // Initialize the captured struct.
2373   LValue SlotLV =
2374     MakeAddrLValue(CreateMemTemp(RecordTy, "agg.captured"), RecordTy);
2375 
2376   RecordDecl::field_iterator CurField = RD->field_begin();
2377   for (CapturedStmt::const_capture_init_iterator I = S.capture_init_begin(),
2378                                                  E = S.capture_init_end();
2379        I != E; ++I, ++CurField) {
2380     LValue LV = EmitLValueForFieldInitialization(SlotLV, *CurField);
2381     if (CurField->hasCapturedVLAType()) {
2382       auto VAT = CurField->getCapturedVLAType();
2383       EmitStoreThroughLValue(RValue::get(VLASizeMap[VAT->getSizeExpr()]), LV);
2384     } else {
2385       EmitInitializerForField(*CurField, LV, *I);
2386     }
2387   }
2388 
2389   return SlotLV;
2390 }
2391 
2392 /// Generate an outlined function for the body of a CapturedStmt, store any
2393 /// captured variables into the captured struct, and call the outlined function.
2394 llvm::Function *
2395 CodeGenFunction::EmitCapturedStmt(const CapturedStmt &S, CapturedRegionKind K) {
2396   LValue CapStruct = InitCapturedStruct(S);
2397 
2398   // Emit the CapturedDecl
2399   CodeGenFunction CGF(CGM, true);
2400   CGCapturedStmtRAII CapInfoRAII(CGF, new CGCapturedStmtInfo(S, K));
2401   llvm::Function *F = CGF.GenerateCapturedStmtFunction(S);
2402   delete CGF.CapturedStmtInfo;
2403 
2404   // Emit call to the helper function.
2405   EmitCallOrInvoke(F, CapStruct.getPointer(*this));
2406 
2407   return F;
2408 }
2409 
2410 Address CodeGenFunction::GenerateCapturedStmtArgument(const CapturedStmt &S) {
2411   LValue CapStruct = InitCapturedStruct(S);
2412   return CapStruct.getAddress(*this);
2413 }
2414 
2415 /// Creates the outlined function for a CapturedStmt.
2416 llvm::Function *
2417 CodeGenFunction::GenerateCapturedStmtFunction(const CapturedStmt &S) {
2418   assert(CapturedStmtInfo &&
2419     "CapturedStmtInfo should be set when generating the captured function");
2420   const CapturedDecl *CD = S.getCapturedDecl();
2421   const RecordDecl *RD = S.getCapturedRecordDecl();
2422   SourceLocation Loc = S.getBeginLoc();
2423   assert(CD->hasBody() && "missing CapturedDecl body");
2424 
2425   // Build the argument list.
2426   ASTContext &Ctx = CGM.getContext();
2427   FunctionArgList Args;
2428   Args.append(CD->param_begin(), CD->param_end());
2429 
2430   // Create the function declaration.
2431   const CGFunctionInfo &FuncInfo =
2432     CGM.getTypes().arrangeBuiltinFunctionDeclaration(Ctx.VoidTy, Args);
2433   llvm::FunctionType *FuncLLVMTy = CGM.getTypes().GetFunctionType(FuncInfo);
2434 
2435   llvm::Function *F =
2436     llvm::Function::Create(FuncLLVMTy, llvm::GlobalValue::InternalLinkage,
2437                            CapturedStmtInfo->getHelperName(), &CGM.getModule());
2438   CGM.SetInternalFunctionAttributes(CD, F, FuncInfo);
2439   if (CD->isNothrow())
2440     F->addFnAttr(llvm::Attribute::NoUnwind);
2441 
2442   // Generate the function.
2443   StartFunction(CD, Ctx.VoidTy, F, FuncInfo, Args, CD->getLocation(),
2444                 CD->getBody()->getBeginLoc());
2445   // Set the context parameter in CapturedStmtInfo.
2446   Address DeclPtr = GetAddrOfLocalVar(CD->getContextParam());
2447   CapturedStmtInfo->setContextValue(Builder.CreateLoad(DeclPtr));
2448 
2449   // Initialize variable-length arrays.
2450   LValue Base = MakeNaturalAlignAddrLValue(CapturedStmtInfo->getContextValue(),
2451                                            Ctx.getTagDeclType(RD));
2452   for (auto *FD : RD->fields()) {
2453     if (FD->hasCapturedVLAType()) {
2454       auto *ExprArg =
2455           EmitLoadOfLValue(EmitLValueForField(Base, FD), S.getBeginLoc())
2456               .getScalarVal();
2457       auto VAT = FD->getCapturedVLAType();
2458       VLASizeMap[VAT->getSizeExpr()] = ExprArg;
2459     }
2460   }
2461 
2462   // If 'this' is captured, load it into CXXThisValue.
2463   if (CapturedStmtInfo->isCXXThisExprCaptured()) {
2464     FieldDecl *FD = CapturedStmtInfo->getThisFieldDecl();
2465     LValue ThisLValue = EmitLValueForField(Base, FD);
2466     CXXThisValue = EmitLoadOfLValue(ThisLValue, Loc).getScalarVal();
2467   }
2468 
2469   PGO.assignRegionCounters(GlobalDecl(CD), F);
2470   CapturedStmtInfo->EmitBody(*this, CD->getBody());
2471   FinishFunction(CD->getBodyRBrace());
2472 
2473   return F;
2474 }
2475