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