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 "CGOpenMPRuntime.h"
15 #include "CodeGenFunction.h"
16 #include "CodeGenModule.h"
17 #include "TargetInfo.h"
18 #include "clang/AST/Attr.h"
19 #include "clang/AST/Expr.h"
20 #include "clang/AST/Stmt.h"
21 #include "clang/AST/StmtVisitor.h"
22 #include "clang/Basic/Builtins.h"
23 #include "clang/Basic/DiagnosticSema.h"
24 #include "clang/Basic/PrettyStackTrace.h"
25 #include "clang/Basic/SourceManager.h"
26 #include "clang/Basic/TargetInfo.h"
27 #include "llvm/ADT/SmallSet.h"
28 #include "llvm/ADT/StringExtras.h"
29 #include "llvm/IR/Assumptions.h"
30 #include "llvm/IR/DataLayout.h"
31 #include "llvm/IR/InlineAsm.h"
32 #include "llvm/IR/Intrinsics.h"
33 #include "llvm/IR/MDBuilder.h"
34 #include "llvm/Support/SaveAndRestore.h"
35 
36 using namespace clang;
37 using namespace CodeGen;
38 
39 //===----------------------------------------------------------------------===//
40 //                              Statement Emission
41 //===----------------------------------------------------------------------===//
42 
43 void CodeGenFunction::EmitStopPoint(const Stmt *S) {
44   if (CGDebugInfo *DI = getDebugInfo()) {
45     SourceLocation Loc;
46     Loc = S->getBeginLoc();
47     DI->EmitLocation(Builder, Loc);
48 
49     LastStopPoint = Loc;
50   }
51 }
52 
53 void CodeGenFunction::EmitStmt(const Stmt *S, ArrayRef<const Attr *> Attrs) {
54   assert(S && "Null statement?");
55   PGO.setCurrentStmt(S);
56 
57   // These statements have their own debug info handling.
58   if (EmitSimpleStmt(S, Attrs))
59     return;
60 
61   // Check if we are generating unreachable code.
62   if (!HaveInsertPoint()) {
63     // If so, and the statement doesn't contain a label, then we do not need to
64     // generate actual code. This is safe because (1) the current point is
65     // unreachable, so we don't need to execute the code, and (2) we've already
66     // handled the statements which update internal data structures (like the
67     // local variable map) which could be used by subsequent statements.
68     if (!ContainsLabel(S)) {
69       // Verify that any decl statements were handled as simple, they may be in
70       // scope of subsequent reachable statements.
71       assert(!isa<DeclStmt>(*S) && "Unexpected DeclStmt!");
72       return;
73     }
74 
75     // Otherwise, make a new block to hold the code.
76     EnsureInsertPoint();
77   }
78 
79   // Generate a stoppoint if we are emitting debug info.
80   EmitStopPoint(S);
81 
82   // Ignore all OpenMP directives except for simd if OpenMP with Simd is
83   // enabled.
84   if (getLangOpts().OpenMP && getLangOpts().OpenMPSimd) {
85     if (const auto *D = dyn_cast<OMPExecutableDirective>(S)) {
86       EmitSimpleOMPExecutableDirective(*D);
87       return;
88     }
89   }
90 
91   switch (S->getStmtClass()) {
92   case Stmt::NoStmtClass:
93   case Stmt::CXXCatchStmtClass:
94   case Stmt::SEHExceptStmtClass:
95   case Stmt::SEHFinallyStmtClass:
96   case Stmt::MSDependentExistsStmtClass:
97     llvm_unreachable("invalid statement class to emit generically");
98   case Stmt::NullStmtClass:
99   case Stmt::CompoundStmtClass:
100   case Stmt::DeclStmtClass:
101   case Stmt::LabelStmtClass:
102   case Stmt::AttributedStmtClass:
103   case Stmt::GotoStmtClass:
104   case Stmt::BreakStmtClass:
105   case Stmt::ContinueStmtClass:
106   case Stmt::DefaultStmtClass:
107   case Stmt::CaseStmtClass:
108   case Stmt::SEHLeaveStmtClass:
109     llvm_unreachable("should have emitted these statements as simple");
110 
111 #define STMT(Type, Base)
112 #define ABSTRACT_STMT(Op)
113 #define EXPR(Type, Base) \
114   case Stmt::Type##Class:
115 #include "clang/AST/StmtNodes.inc"
116   {
117     // Remember the block we came in on.
118     llvm::BasicBlock *incoming = Builder.GetInsertBlock();
119     assert(incoming && "expression emission must have an insertion point");
120 
121     EmitIgnoredExpr(cast<Expr>(S));
122 
123     llvm::BasicBlock *outgoing = Builder.GetInsertBlock();
124     assert(outgoing && "expression emission cleared block!");
125 
126     // The expression emitters assume (reasonably!) that the insertion
127     // point is always set.  To maintain that, the call-emission code
128     // for noreturn functions has to enter a new block with no
129     // predecessors.  We want to kill that block and mark the current
130     // insertion point unreachable in the common case of a call like
131     // "exit();".  Since expression emission doesn't otherwise create
132     // blocks with no predecessors, we can just test for that.
133     // However, we must be careful not to do this to our incoming
134     // block, because *statement* emission does sometimes create
135     // reachable blocks which will have no predecessors until later in
136     // the function.  This occurs with, e.g., labels that are not
137     // reachable by fallthrough.
138     if (incoming != outgoing && outgoing->use_empty()) {
139       outgoing->eraseFromParent();
140       Builder.ClearInsertionPoint();
141     }
142     break;
143   }
144 
145   case Stmt::IndirectGotoStmtClass:
146     EmitIndirectGotoStmt(cast<IndirectGotoStmt>(*S)); break;
147 
148   case Stmt::IfStmtClass:      EmitIfStmt(cast<IfStmt>(*S));              break;
149   case Stmt::WhileStmtClass:   EmitWhileStmt(cast<WhileStmt>(*S), Attrs); break;
150   case Stmt::DoStmtClass:      EmitDoStmt(cast<DoStmt>(*S), Attrs);       break;
151   case Stmt::ForStmtClass:     EmitForStmt(cast<ForStmt>(*S), Attrs);     break;
152 
153   case Stmt::ReturnStmtClass:  EmitReturnStmt(cast<ReturnStmt>(*S));      break;
154 
155   case Stmt::SwitchStmtClass:  EmitSwitchStmt(cast<SwitchStmt>(*S));      break;
156   case Stmt::GCCAsmStmtClass:  // Intentional fall-through.
157   case Stmt::MSAsmStmtClass:   EmitAsmStmt(cast<AsmStmt>(*S));            break;
158   case Stmt::CoroutineBodyStmtClass:
159     EmitCoroutineBody(cast<CoroutineBodyStmt>(*S));
160     break;
161   case Stmt::CoreturnStmtClass:
162     EmitCoreturnStmt(cast<CoreturnStmt>(*S));
163     break;
164   case Stmt::CapturedStmtClass: {
165     const CapturedStmt *CS = cast<CapturedStmt>(S);
166     EmitCapturedStmt(*CS, CS->getCapturedRegionKind());
167     }
168     break;
169   case Stmt::ObjCAtTryStmtClass:
170     EmitObjCAtTryStmt(cast<ObjCAtTryStmt>(*S));
171     break;
172   case Stmt::ObjCAtCatchStmtClass:
173     llvm_unreachable(
174                     "@catch statements should be handled by EmitObjCAtTryStmt");
175   case Stmt::ObjCAtFinallyStmtClass:
176     llvm_unreachable(
177                   "@finally statements should be handled by EmitObjCAtTryStmt");
178   case Stmt::ObjCAtThrowStmtClass:
179     EmitObjCAtThrowStmt(cast<ObjCAtThrowStmt>(*S));
180     break;
181   case Stmt::ObjCAtSynchronizedStmtClass:
182     EmitObjCAtSynchronizedStmt(cast<ObjCAtSynchronizedStmt>(*S));
183     break;
184   case Stmt::ObjCForCollectionStmtClass:
185     EmitObjCForCollectionStmt(cast<ObjCForCollectionStmt>(*S));
186     break;
187   case Stmt::ObjCAutoreleasePoolStmtClass:
188     EmitObjCAutoreleasePoolStmt(cast<ObjCAutoreleasePoolStmt>(*S));
189     break;
190 
191   case Stmt::CXXTryStmtClass:
192     EmitCXXTryStmt(cast<CXXTryStmt>(*S));
193     break;
194   case Stmt::CXXForRangeStmtClass:
195     EmitCXXForRangeStmt(cast<CXXForRangeStmt>(*S), Attrs);
196     break;
197   case Stmt::SEHTryStmtClass:
198     EmitSEHTryStmt(cast<SEHTryStmt>(*S));
199     break;
200   case Stmt::OMPMetaDirectiveClass:
201     EmitOMPMetaDirective(cast<OMPMetaDirective>(*S));
202     break;
203   case Stmt::OMPCanonicalLoopClass:
204     EmitOMPCanonicalLoop(cast<OMPCanonicalLoop>(S));
205     break;
206   case Stmt::OMPParallelDirectiveClass:
207     EmitOMPParallelDirective(cast<OMPParallelDirective>(*S));
208     break;
209   case Stmt::OMPSimdDirectiveClass:
210     EmitOMPSimdDirective(cast<OMPSimdDirective>(*S));
211     break;
212   case Stmt::OMPTileDirectiveClass:
213     EmitOMPTileDirective(cast<OMPTileDirective>(*S));
214     break;
215   case Stmt::OMPUnrollDirectiveClass:
216     EmitOMPUnrollDirective(cast<OMPUnrollDirective>(*S));
217     break;
218   case Stmt::OMPForDirectiveClass:
219     EmitOMPForDirective(cast<OMPForDirective>(*S));
220     break;
221   case Stmt::OMPForSimdDirectiveClass:
222     EmitOMPForSimdDirective(cast<OMPForSimdDirective>(*S));
223     break;
224   case Stmt::OMPSectionsDirectiveClass:
225     EmitOMPSectionsDirective(cast<OMPSectionsDirective>(*S));
226     break;
227   case Stmt::OMPSectionDirectiveClass:
228     EmitOMPSectionDirective(cast<OMPSectionDirective>(*S));
229     break;
230   case Stmt::OMPSingleDirectiveClass:
231     EmitOMPSingleDirective(cast<OMPSingleDirective>(*S));
232     break;
233   case Stmt::OMPMasterDirectiveClass:
234     EmitOMPMasterDirective(cast<OMPMasterDirective>(*S));
235     break;
236   case Stmt::OMPCriticalDirectiveClass:
237     EmitOMPCriticalDirective(cast<OMPCriticalDirective>(*S));
238     break;
239   case Stmt::OMPParallelForDirectiveClass:
240     EmitOMPParallelForDirective(cast<OMPParallelForDirective>(*S));
241     break;
242   case Stmt::OMPParallelForSimdDirectiveClass:
243     EmitOMPParallelForSimdDirective(cast<OMPParallelForSimdDirective>(*S));
244     break;
245   case Stmt::OMPParallelMasterDirectiveClass:
246     EmitOMPParallelMasterDirective(cast<OMPParallelMasterDirective>(*S));
247     break;
248   case Stmt::OMPParallelSectionsDirectiveClass:
249     EmitOMPParallelSectionsDirective(cast<OMPParallelSectionsDirective>(*S));
250     break;
251   case Stmt::OMPTaskDirectiveClass:
252     EmitOMPTaskDirective(cast<OMPTaskDirective>(*S));
253     break;
254   case Stmt::OMPTaskyieldDirectiveClass:
255     EmitOMPTaskyieldDirective(cast<OMPTaskyieldDirective>(*S));
256     break;
257   case Stmt::OMPBarrierDirectiveClass:
258     EmitOMPBarrierDirective(cast<OMPBarrierDirective>(*S));
259     break;
260   case Stmt::OMPTaskwaitDirectiveClass:
261     EmitOMPTaskwaitDirective(cast<OMPTaskwaitDirective>(*S));
262     break;
263   case Stmt::OMPTaskgroupDirectiveClass:
264     EmitOMPTaskgroupDirective(cast<OMPTaskgroupDirective>(*S));
265     break;
266   case Stmt::OMPFlushDirectiveClass:
267     EmitOMPFlushDirective(cast<OMPFlushDirective>(*S));
268     break;
269   case Stmt::OMPDepobjDirectiveClass:
270     EmitOMPDepobjDirective(cast<OMPDepobjDirective>(*S));
271     break;
272   case Stmt::OMPScanDirectiveClass:
273     EmitOMPScanDirective(cast<OMPScanDirective>(*S));
274     break;
275   case Stmt::OMPOrderedDirectiveClass:
276     EmitOMPOrderedDirective(cast<OMPOrderedDirective>(*S));
277     break;
278   case Stmt::OMPAtomicDirectiveClass:
279     EmitOMPAtomicDirective(cast<OMPAtomicDirective>(*S));
280     break;
281   case Stmt::OMPTargetDirectiveClass:
282     EmitOMPTargetDirective(cast<OMPTargetDirective>(*S));
283     break;
284   case Stmt::OMPTeamsDirectiveClass:
285     EmitOMPTeamsDirective(cast<OMPTeamsDirective>(*S));
286     break;
287   case Stmt::OMPCancellationPointDirectiveClass:
288     EmitOMPCancellationPointDirective(cast<OMPCancellationPointDirective>(*S));
289     break;
290   case Stmt::OMPCancelDirectiveClass:
291     EmitOMPCancelDirective(cast<OMPCancelDirective>(*S));
292     break;
293   case Stmt::OMPTargetDataDirectiveClass:
294     EmitOMPTargetDataDirective(cast<OMPTargetDataDirective>(*S));
295     break;
296   case Stmt::OMPTargetEnterDataDirectiveClass:
297     EmitOMPTargetEnterDataDirective(cast<OMPTargetEnterDataDirective>(*S));
298     break;
299   case Stmt::OMPTargetExitDataDirectiveClass:
300     EmitOMPTargetExitDataDirective(cast<OMPTargetExitDataDirective>(*S));
301     break;
302   case Stmt::OMPTargetParallelDirectiveClass:
303     EmitOMPTargetParallelDirective(cast<OMPTargetParallelDirective>(*S));
304     break;
305   case Stmt::OMPTargetParallelForDirectiveClass:
306     EmitOMPTargetParallelForDirective(cast<OMPTargetParallelForDirective>(*S));
307     break;
308   case Stmt::OMPTaskLoopDirectiveClass:
309     EmitOMPTaskLoopDirective(cast<OMPTaskLoopDirective>(*S));
310     break;
311   case Stmt::OMPTaskLoopSimdDirectiveClass:
312     EmitOMPTaskLoopSimdDirective(cast<OMPTaskLoopSimdDirective>(*S));
313     break;
314   case Stmt::OMPMasterTaskLoopDirectiveClass:
315     EmitOMPMasterTaskLoopDirective(cast<OMPMasterTaskLoopDirective>(*S));
316     break;
317   case Stmt::OMPMaskedTaskLoopDirectiveClass:
318     llvm_unreachable("masked taskloop directive not supported yet.");
319     break;
320   case Stmt::OMPMasterTaskLoopSimdDirectiveClass:
321     EmitOMPMasterTaskLoopSimdDirective(
322         cast<OMPMasterTaskLoopSimdDirective>(*S));
323     break;
324   case Stmt::OMPMaskedTaskLoopSimdDirectiveClass:
325     llvm_unreachable("masked taskloop simd directive not supported yet.");
326     break;
327   case Stmt::OMPParallelMasterTaskLoopDirectiveClass:
328     EmitOMPParallelMasterTaskLoopDirective(
329         cast<OMPParallelMasterTaskLoopDirective>(*S));
330     break;
331   case Stmt::OMPParallelMaskedTaskLoopDirectiveClass:
332     llvm_unreachable("parallel masked taskloop directive not supported yet.");
333     break;
334   case Stmt::OMPParallelMasterTaskLoopSimdDirectiveClass:
335     EmitOMPParallelMasterTaskLoopSimdDirective(
336         cast<OMPParallelMasterTaskLoopSimdDirective>(*S));
337     break;
338   case Stmt::OMPParallelMaskedTaskLoopSimdDirectiveClass:
339     llvm_unreachable(
340         "parallel masked taskloop simd directive not supported yet.");
341     break;
342   case Stmt::OMPDistributeDirectiveClass:
343     EmitOMPDistributeDirective(cast<OMPDistributeDirective>(*S));
344     break;
345   case Stmt::OMPTargetUpdateDirectiveClass:
346     EmitOMPTargetUpdateDirective(cast<OMPTargetUpdateDirective>(*S));
347     break;
348   case Stmt::OMPDistributeParallelForDirectiveClass:
349     EmitOMPDistributeParallelForDirective(
350         cast<OMPDistributeParallelForDirective>(*S));
351     break;
352   case Stmt::OMPDistributeParallelForSimdDirectiveClass:
353     EmitOMPDistributeParallelForSimdDirective(
354         cast<OMPDistributeParallelForSimdDirective>(*S));
355     break;
356   case Stmt::OMPDistributeSimdDirectiveClass:
357     EmitOMPDistributeSimdDirective(cast<OMPDistributeSimdDirective>(*S));
358     break;
359   case Stmt::OMPTargetParallelForSimdDirectiveClass:
360     EmitOMPTargetParallelForSimdDirective(
361         cast<OMPTargetParallelForSimdDirective>(*S));
362     break;
363   case Stmt::OMPTargetSimdDirectiveClass:
364     EmitOMPTargetSimdDirective(cast<OMPTargetSimdDirective>(*S));
365     break;
366   case Stmt::OMPTeamsDistributeDirectiveClass:
367     EmitOMPTeamsDistributeDirective(cast<OMPTeamsDistributeDirective>(*S));
368     break;
369   case Stmt::OMPTeamsDistributeSimdDirectiveClass:
370     EmitOMPTeamsDistributeSimdDirective(
371         cast<OMPTeamsDistributeSimdDirective>(*S));
372     break;
373   case Stmt::OMPTeamsDistributeParallelForSimdDirectiveClass:
374     EmitOMPTeamsDistributeParallelForSimdDirective(
375         cast<OMPTeamsDistributeParallelForSimdDirective>(*S));
376     break;
377   case Stmt::OMPTeamsDistributeParallelForDirectiveClass:
378     EmitOMPTeamsDistributeParallelForDirective(
379         cast<OMPTeamsDistributeParallelForDirective>(*S));
380     break;
381   case Stmt::OMPTargetTeamsDirectiveClass:
382     EmitOMPTargetTeamsDirective(cast<OMPTargetTeamsDirective>(*S));
383     break;
384   case Stmt::OMPTargetTeamsDistributeDirectiveClass:
385     EmitOMPTargetTeamsDistributeDirective(
386         cast<OMPTargetTeamsDistributeDirective>(*S));
387     break;
388   case Stmt::OMPTargetTeamsDistributeParallelForDirectiveClass:
389     EmitOMPTargetTeamsDistributeParallelForDirective(
390         cast<OMPTargetTeamsDistributeParallelForDirective>(*S));
391     break;
392   case Stmt::OMPTargetTeamsDistributeParallelForSimdDirectiveClass:
393     EmitOMPTargetTeamsDistributeParallelForSimdDirective(
394         cast<OMPTargetTeamsDistributeParallelForSimdDirective>(*S));
395     break;
396   case Stmt::OMPTargetTeamsDistributeSimdDirectiveClass:
397     EmitOMPTargetTeamsDistributeSimdDirective(
398         cast<OMPTargetTeamsDistributeSimdDirective>(*S));
399     break;
400   case Stmt::OMPInteropDirectiveClass:
401     EmitOMPInteropDirective(cast<OMPInteropDirective>(*S));
402     break;
403   case Stmt::OMPDispatchDirectiveClass:
404     llvm_unreachable("Dispatch directive not supported yet.");
405     break;
406   case Stmt::OMPMaskedDirectiveClass:
407     EmitOMPMaskedDirective(cast<OMPMaskedDirective>(*S));
408     break;
409   case Stmt::OMPGenericLoopDirectiveClass:
410     EmitOMPGenericLoopDirective(cast<OMPGenericLoopDirective>(*S));
411     break;
412   case Stmt::OMPTeamsGenericLoopDirectiveClass:
413     llvm_unreachable("teams loop directive not supported yet.");
414     break;
415   case Stmt::OMPTargetTeamsGenericLoopDirectiveClass:
416     llvm_unreachable("target teams loop directive not supported yet.");
417     break;
418   case Stmt::OMPParallelGenericLoopDirectiveClass:
419     llvm_unreachable("parallel loop directive not supported yet.");
420     break;
421   case Stmt::OMPTargetParallelGenericLoopDirectiveClass:
422     llvm_unreachable("target parallel loop directive not supported yet.");
423     break;
424   case Stmt::OMPParallelMaskedDirectiveClass:
425     llvm_unreachable("parallel masked directive not supported yet.");
426     break;
427   }
428 }
429 
430 bool CodeGenFunction::EmitSimpleStmt(const Stmt *S,
431                                      ArrayRef<const Attr *> Attrs) {
432   switch (S->getStmtClass()) {
433   default:
434     return false;
435   case Stmt::NullStmtClass:
436     break;
437   case Stmt::CompoundStmtClass:
438     EmitCompoundStmt(cast<CompoundStmt>(*S));
439     break;
440   case Stmt::DeclStmtClass:
441     EmitDeclStmt(cast<DeclStmt>(*S));
442     break;
443   case Stmt::LabelStmtClass:
444     EmitLabelStmt(cast<LabelStmt>(*S));
445     break;
446   case Stmt::AttributedStmtClass:
447     EmitAttributedStmt(cast<AttributedStmt>(*S));
448     break;
449   case Stmt::GotoStmtClass:
450     EmitGotoStmt(cast<GotoStmt>(*S));
451     break;
452   case Stmt::BreakStmtClass:
453     EmitBreakStmt(cast<BreakStmt>(*S));
454     break;
455   case Stmt::ContinueStmtClass:
456     EmitContinueStmt(cast<ContinueStmt>(*S));
457     break;
458   case Stmt::DefaultStmtClass:
459     EmitDefaultStmt(cast<DefaultStmt>(*S), Attrs);
460     break;
461   case Stmt::CaseStmtClass:
462     EmitCaseStmt(cast<CaseStmt>(*S), Attrs);
463     break;
464   case Stmt::SEHLeaveStmtClass:
465     EmitSEHLeaveStmt(cast<SEHLeaveStmt>(*S));
466     break;
467   }
468   return true;
469 }
470 
471 /// EmitCompoundStmt - Emit a compound statement {..} node.  If GetLast is true,
472 /// this captures the expression result of the last sub-statement and returns it
473 /// (for use by the statement expression extension).
474 Address CodeGenFunction::EmitCompoundStmt(const CompoundStmt &S, bool GetLast,
475                                           AggValueSlot AggSlot) {
476   PrettyStackTraceLoc CrashInfo(getContext().getSourceManager(),S.getLBracLoc(),
477                              "LLVM IR generation of compound statement ('{}')");
478 
479   // Keep track of the current cleanup stack depth, including debug scopes.
480   LexicalScope Scope(*this, S.getSourceRange());
481 
482   return EmitCompoundStmtWithoutScope(S, GetLast, AggSlot);
483 }
484 
485 Address
486 CodeGenFunction::EmitCompoundStmtWithoutScope(const CompoundStmt &S,
487                                               bool GetLast,
488                                               AggValueSlot AggSlot) {
489 
490   const Stmt *ExprResult = S.getStmtExprResult();
491   assert((!GetLast || (GetLast && ExprResult)) &&
492          "If GetLast is true then the CompoundStmt must have a StmtExprResult");
493 
494   Address RetAlloca = Address::invalid();
495 
496   for (auto *CurStmt : S.body()) {
497     if (GetLast && ExprResult == CurStmt) {
498       // We have to special case labels here.  They are statements, but when put
499       // at the end of a statement expression, they yield the value of their
500       // subexpression.  Handle this by walking through all labels we encounter,
501       // emitting them before we evaluate the subexpr.
502       // Similar issues arise for attributed statements.
503       while (!isa<Expr>(ExprResult)) {
504         if (const auto *LS = dyn_cast<LabelStmt>(ExprResult)) {
505           EmitLabel(LS->getDecl());
506           ExprResult = LS->getSubStmt();
507         } else if (const auto *AS = dyn_cast<AttributedStmt>(ExprResult)) {
508           // FIXME: Update this if we ever have attributes that affect the
509           // semantics of an expression.
510           ExprResult = AS->getSubStmt();
511         } else {
512           llvm_unreachable("unknown value statement");
513         }
514       }
515 
516       EnsureInsertPoint();
517 
518       const Expr *E = cast<Expr>(ExprResult);
519       QualType ExprTy = E->getType();
520       if (hasAggregateEvaluationKind(ExprTy)) {
521         EmitAggExpr(E, AggSlot);
522       } else {
523         // We can't return an RValue here because there might be cleanups at
524         // the end of the StmtExpr.  Because of that, we have to emit the result
525         // here into a temporary alloca.
526         RetAlloca = CreateMemTemp(ExprTy);
527         EmitAnyExprToMem(E, RetAlloca, Qualifiers(),
528                          /*IsInit*/ false);
529       }
530     } else {
531       EmitStmt(CurStmt);
532     }
533   }
534 
535   return RetAlloca;
536 }
537 
538 void CodeGenFunction::SimplifyForwardingBlocks(llvm::BasicBlock *BB) {
539   llvm::BranchInst *BI = dyn_cast<llvm::BranchInst>(BB->getTerminator());
540 
541   // If there is a cleanup stack, then we it isn't worth trying to
542   // simplify this block (we would need to remove it from the scope map
543   // and cleanup entry).
544   if (!EHStack.empty())
545     return;
546 
547   // Can only simplify direct branches.
548   if (!BI || !BI->isUnconditional())
549     return;
550 
551   // Can only simplify empty blocks.
552   if (BI->getIterator() != BB->begin())
553     return;
554 
555   BB->replaceAllUsesWith(BI->getSuccessor(0));
556   BI->eraseFromParent();
557   BB->eraseFromParent();
558 }
559 
560 void CodeGenFunction::EmitBlock(llvm::BasicBlock *BB, bool IsFinished) {
561   llvm::BasicBlock *CurBB = Builder.GetInsertBlock();
562 
563   // Fall out of the current block (if necessary).
564   EmitBranch(BB);
565 
566   if (IsFinished && BB->use_empty()) {
567     delete BB;
568     return;
569   }
570 
571   // Place the block after the current block, if possible, or else at
572   // the end of the function.
573   if (CurBB && CurBB->getParent())
574     CurFn->getBasicBlockList().insertAfter(CurBB->getIterator(), BB);
575   else
576     CurFn->getBasicBlockList().push_back(BB);
577   Builder.SetInsertPoint(BB);
578 }
579 
580 void CodeGenFunction::EmitBranch(llvm::BasicBlock *Target) {
581   // Emit a branch from the current block to the target one if this
582   // was a real block.  If this was just a fall-through block after a
583   // terminator, don't emit it.
584   llvm::BasicBlock *CurBB = Builder.GetInsertBlock();
585 
586   if (!CurBB || CurBB->getTerminator()) {
587     // If there is no insert point or the previous block is already
588     // terminated, don't touch it.
589   } else {
590     // Otherwise, create a fall-through branch.
591     Builder.CreateBr(Target);
592   }
593 
594   Builder.ClearInsertionPoint();
595 }
596 
597 void CodeGenFunction::EmitBlockAfterUses(llvm::BasicBlock *block) {
598   bool inserted = false;
599   for (llvm::User *u : block->users()) {
600     if (llvm::Instruction *insn = dyn_cast<llvm::Instruction>(u)) {
601       CurFn->getBasicBlockList().insertAfter(insn->getParent()->getIterator(),
602                                              block);
603       inserted = true;
604       break;
605     }
606   }
607 
608   if (!inserted)
609     CurFn->getBasicBlockList().push_back(block);
610 
611   Builder.SetInsertPoint(block);
612 }
613 
614 CodeGenFunction::JumpDest
615 CodeGenFunction::getJumpDestForLabel(const LabelDecl *D) {
616   JumpDest &Dest = LabelMap[D];
617   if (Dest.isValid()) return Dest;
618 
619   // Create, but don't insert, the new block.
620   Dest = JumpDest(createBasicBlock(D->getName()),
621                   EHScopeStack::stable_iterator::invalid(),
622                   NextCleanupDestIndex++);
623   return Dest;
624 }
625 
626 void CodeGenFunction::EmitLabel(const LabelDecl *D) {
627   // Add this label to the current lexical scope if we're within any
628   // normal cleanups.  Jumps "in" to this label --- when permitted by
629   // the language --- may need to be routed around such cleanups.
630   if (EHStack.hasNormalCleanups() && CurLexicalScope)
631     CurLexicalScope->addLabel(D);
632 
633   JumpDest &Dest = LabelMap[D];
634 
635   // If we didn't need a forward reference to this label, just go
636   // ahead and create a destination at the current scope.
637   if (!Dest.isValid()) {
638     Dest = getJumpDestInCurrentScope(D->getName());
639 
640   // Otherwise, we need to give this label a target depth and remove
641   // it from the branch-fixups list.
642   } else {
643     assert(!Dest.getScopeDepth().isValid() && "already emitted label!");
644     Dest.setScopeDepth(EHStack.stable_begin());
645     ResolveBranchFixups(Dest.getBlock());
646   }
647 
648   EmitBlock(Dest.getBlock());
649 
650   // Emit debug info for labels.
651   if (CGDebugInfo *DI = getDebugInfo()) {
652     if (CGM.getCodeGenOpts().hasReducedDebugInfo()) {
653       DI->setLocation(D->getLocation());
654       DI->EmitLabel(D, Builder);
655     }
656   }
657 
658   incrementProfileCounter(D->getStmt());
659 }
660 
661 /// Change the cleanup scope of the labels in this lexical scope to
662 /// match the scope of the enclosing context.
663 void CodeGenFunction::LexicalScope::rescopeLabels() {
664   assert(!Labels.empty());
665   EHScopeStack::stable_iterator innermostScope
666     = CGF.EHStack.getInnermostNormalCleanup();
667 
668   // Change the scope depth of all the labels.
669   for (SmallVectorImpl<const LabelDecl*>::const_iterator
670          i = Labels.begin(), e = Labels.end(); i != e; ++i) {
671     assert(CGF.LabelMap.count(*i));
672     JumpDest &dest = CGF.LabelMap.find(*i)->second;
673     assert(dest.getScopeDepth().isValid());
674     assert(innermostScope.encloses(dest.getScopeDepth()));
675     dest.setScopeDepth(innermostScope);
676   }
677 
678   // Reparent the labels if the new scope also has cleanups.
679   if (innermostScope != EHScopeStack::stable_end() && ParentScope) {
680     ParentScope->Labels.append(Labels.begin(), Labels.end());
681   }
682 }
683 
684 
685 void CodeGenFunction::EmitLabelStmt(const LabelStmt &S) {
686   EmitLabel(S.getDecl());
687 
688   // IsEHa - emit eha.scope.begin if it's a side entry of a scope
689   if (getLangOpts().EHAsynch && S.isSideEntry())
690     EmitSehCppScopeBegin();
691 
692   EmitStmt(S.getSubStmt());
693 }
694 
695 void CodeGenFunction::EmitAttributedStmt(const AttributedStmt &S) {
696   bool nomerge = false;
697   bool noinline = false;
698   bool alwaysinline = false;
699   const CallExpr *musttail = nullptr;
700 
701   for (const auto *A : S.getAttrs()) {
702     switch (A->getKind()) {
703     default:
704       break;
705     case attr::NoMerge:
706       nomerge = true;
707       break;
708     case attr::NoInline:
709       noinline = true;
710       break;
711     case attr::AlwaysInline:
712       alwaysinline = true;
713       break;
714     case attr::MustTail:
715       const Stmt *Sub = S.getSubStmt();
716       const ReturnStmt *R = cast<ReturnStmt>(Sub);
717       musttail = cast<CallExpr>(R->getRetValue()->IgnoreParens());
718       break;
719     }
720   }
721   SaveAndRestore<bool> save_nomerge(InNoMergeAttributedStmt, nomerge);
722   SaveAndRestore<bool> save_noinline(InNoInlineAttributedStmt, noinline);
723   SaveAndRestore<bool> save_alwaysinline(InAlwaysInlineAttributedStmt,
724                                          alwaysinline);
725   SaveAndRestore<const CallExpr *> save_musttail(MustTailCall, musttail);
726   EmitStmt(S.getSubStmt(), S.getAttrs());
727 }
728 
729 void CodeGenFunction::EmitGotoStmt(const GotoStmt &S) {
730   // If this code is reachable then emit a stop point (if generating
731   // debug info). We have to do this ourselves because we are on the
732   // "simple" statement path.
733   if (HaveInsertPoint())
734     EmitStopPoint(&S);
735 
736   EmitBranchThroughCleanup(getJumpDestForLabel(S.getLabel()));
737 }
738 
739 
740 void CodeGenFunction::EmitIndirectGotoStmt(const IndirectGotoStmt &S) {
741   if (const LabelDecl *Target = S.getConstantTarget()) {
742     EmitBranchThroughCleanup(getJumpDestForLabel(Target));
743     return;
744   }
745 
746   // Ensure that we have an i8* for our PHI node.
747   llvm::Value *V = Builder.CreateBitCast(EmitScalarExpr(S.getTarget()),
748                                          Int8PtrTy, "addr");
749   llvm::BasicBlock *CurBB = Builder.GetInsertBlock();
750 
751   // Get the basic block for the indirect goto.
752   llvm::BasicBlock *IndGotoBB = GetIndirectGotoBlock();
753 
754   // The first instruction in the block has to be the PHI for the switch dest,
755   // add an entry for this branch.
756   cast<llvm::PHINode>(IndGotoBB->begin())->addIncoming(V, CurBB);
757 
758   EmitBranch(IndGotoBB);
759 }
760 
761 void CodeGenFunction::EmitIfStmt(const IfStmt &S) {
762   // The else branch of a consteval if statement is always the only branch that
763   // can be runtime evaluated.
764   if (S.isConsteval()) {
765     const Stmt *Executed = S.isNegatedConsteval() ? S.getThen() : S.getElse();
766     if (Executed) {
767       RunCleanupsScope ExecutedScope(*this);
768       EmitStmt(Executed);
769     }
770     return;
771   }
772 
773   // C99 6.8.4.1: The first substatement is executed if the expression compares
774   // unequal to 0.  The condition must be a scalar type.
775   LexicalScope ConditionScope(*this, S.getCond()->getSourceRange());
776 
777   if (S.getInit())
778     EmitStmt(S.getInit());
779 
780   if (S.getConditionVariable())
781     EmitDecl(*S.getConditionVariable());
782 
783   // If the condition constant folds and can be elided, try to avoid emitting
784   // the condition and the dead arm of the if/else.
785   bool CondConstant;
786   if (ConstantFoldsToSimpleInteger(S.getCond(), CondConstant,
787                                    S.isConstexpr())) {
788     // Figure out which block (then or else) is executed.
789     const Stmt *Executed = S.getThen();
790     const Stmt *Skipped  = S.getElse();
791     if (!CondConstant)  // Condition false?
792       std::swap(Executed, Skipped);
793 
794     // If the skipped block has no labels in it, just emit the executed block.
795     // This avoids emitting dead code and simplifies the CFG substantially.
796     if (S.isConstexpr() || !ContainsLabel(Skipped)) {
797       if (CondConstant)
798         incrementProfileCounter(&S);
799       if (Executed) {
800         RunCleanupsScope ExecutedScope(*this);
801         EmitStmt(Executed);
802       }
803       return;
804     }
805   }
806 
807   // Otherwise, the condition did not fold, or we couldn't elide it.  Just emit
808   // the conditional branch.
809   llvm::BasicBlock *ThenBlock = createBasicBlock("if.then");
810   llvm::BasicBlock *ContBlock = createBasicBlock("if.end");
811   llvm::BasicBlock *ElseBlock = ContBlock;
812   if (S.getElse())
813     ElseBlock = createBasicBlock("if.else");
814 
815   // Prefer the PGO based weights over the likelihood attribute.
816   // When the build isn't optimized the metadata isn't used, so don't generate
817   // it.
818   Stmt::Likelihood LH = Stmt::LH_None;
819   uint64_t Count = getProfileCount(S.getThen());
820   if (!Count && CGM.getCodeGenOpts().OptimizationLevel)
821     LH = Stmt::getLikelihood(S.getThen(), S.getElse());
822   EmitBranchOnBoolExpr(S.getCond(), ThenBlock, ElseBlock, Count, LH);
823 
824   // Emit the 'then' code.
825   EmitBlock(ThenBlock);
826   incrementProfileCounter(&S);
827   {
828     RunCleanupsScope ThenScope(*this);
829     EmitStmt(S.getThen());
830   }
831   EmitBranch(ContBlock);
832 
833   // Emit the 'else' code if present.
834   if (const Stmt *Else = S.getElse()) {
835     {
836       // There is no need to emit line number for an unconditional branch.
837       auto NL = ApplyDebugLocation::CreateEmpty(*this);
838       EmitBlock(ElseBlock);
839     }
840     {
841       RunCleanupsScope ElseScope(*this);
842       EmitStmt(Else);
843     }
844     {
845       // There is no need to emit line number for an unconditional branch.
846       auto NL = ApplyDebugLocation::CreateEmpty(*this);
847       EmitBranch(ContBlock);
848     }
849   }
850 
851   // Emit the continuation block for code after the if.
852   EmitBlock(ContBlock, true);
853 }
854 
855 void CodeGenFunction::EmitWhileStmt(const WhileStmt &S,
856                                     ArrayRef<const Attr *> WhileAttrs) {
857   // Emit the header for the loop, which will also become
858   // the continue target.
859   JumpDest LoopHeader = getJumpDestInCurrentScope("while.cond");
860   EmitBlock(LoopHeader.getBlock());
861 
862   // Create an exit block for when the condition fails, which will
863   // also become the break target.
864   JumpDest LoopExit = getJumpDestInCurrentScope("while.end");
865 
866   // Store the blocks to use for break and continue.
867   BreakContinueStack.push_back(BreakContinue(LoopExit, LoopHeader));
868 
869   // C++ [stmt.while]p2:
870   //   When the condition of a while statement is a declaration, the
871   //   scope of the variable that is declared extends from its point
872   //   of declaration (3.3.2) to the end of the while statement.
873   //   [...]
874   //   The object created in a condition is destroyed and created
875   //   with each iteration of the loop.
876   RunCleanupsScope ConditionScope(*this);
877 
878   if (S.getConditionVariable())
879     EmitDecl(*S.getConditionVariable());
880 
881   // Evaluate the conditional in the while header.  C99 6.8.5.1: The
882   // evaluation of the controlling expression takes place before each
883   // execution of the loop body.
884   llvm::Value *BoolCondVal = EvaluateExprAsBool(S.getCond());
885 
886   // while(1) is common, avoid extra exit blocks.  Be sure
887   // to correctly handle break/continue though.
888   llvm::ConstantInt *C = dyn_cast<llvm::ConstantInt>(BoolCondVal);
889   bool CondIsConstInt = C != nullptr;
890   bool EmitBoolCondBranch = !CondIsConstInt || !C->isOne();
891   const SourceRange &R = S.getSourceRange();
892   LoopStack.push(LoopHeader.getBlock(), CGM.getContext(), CGM.getCodeGenOpts(),
893                  WhileAttrs, SourceLocToDebugLoc(R.getBegin()),
894                  SourceLocToDebugLoc(R.getEnd()),
895                  checkIfLoopMustProgress(CondIsConstInt));
896 
897   // As long as the condition is true, go to the loop body.
898   llvm::BasicBlock *LoopBody = createBasicBlock("while.body");
899   if (EmitBoolCondBranch) {
900     llvm::BasicBlock *ExitBlock = LoopExit.getBlock();
901     if (ConditionScope.requiresCleanups())
902       ExitBlock = createBasicBlock("while.exit");
903     llvm::MDNode *Weights =
904         createProfileWeightsForLoop(S.getCond(), getProfileCount(S.getBody()));
905     if (!Weights && CGM.getCodeGenOpts().OptimizationLevel)
906       BoolCondVal = emitCondLikelihoodViaExpectIntrinsic(
907           BoolCondVal, Stmt::getLikelihood(S.getBody()));
908     Builder.CreateCondBr(BoolCondVal, LoopBody, ExitBlock, Weights);
909 
910     if (ExitBlock != LoopExit.getBlock()) {
911       EmitBlock(ExitBlock);
912       EmitBranchThroughCleanup(LoopExit);
913     }
914   } else if (const Attr *A = Stmt::getLikelihoodAttr(S.getBody())) {
915     CGM.getDiags().Report(A->getLocation(),
916                           diag::warn_attribute_has_no_effect_on_infinite_loop)
917         << A << A->getRange();
918     CGM.getDiags().Report(
919         S.getWhileLoc(),
920         diag::note_attribute_has_no_effect_on_infinite_loop_here)
921         << SourceRange(S.getWhileLoc(), S.getRParenLoc());
922   }
923 
924   // Emit the loop body.  We have to emit this in a cleanup scope
925   // because it might be a singleton DeclStmt.
926   {
927     RunCleanupsScope BodyScope(*this);
928     EmitBlock(LoopBody);
929     incrementProfileCounter(&S);
930     EmitStmt(S.getBody());
931   }
932 
933   BreakContinueStack.pop_back();
934 
935   // Immediately force cleanup.
936   ConditionScope.ForceCleanup();
937 
938   EmitStopPoint(&S);
939   // Branch to the loop header again.
940   EmitBranch(LoopHeader.getBlock());
941 
942   LoopStack.pop();
943 
944   // Emit the exit block.
945   EmitBlock(LoopExit.getBlock(), true);
946 
947   // The LoopHeader typically is just a branch if we skipped emitting
948   // a branch, try to erase it.
949   if (!EmitBoolCondBranch)
950     SimplifyForwardingBlocks(LoopHeader.getBlock());
951 }
952 
953 void CodeGenFunction::EmitDoStmt(const DoStmt &S,
954                                  ArrayRef<const Attr *> DoAttrs) {
955   JumpDest LoopExit = getJumpDestInCurrentScope("do.end");
956   JumpDest LoopCond = getJumpDestInCurrentScope("do.cond");
957 
958   uint64_t ParentCount = getCurrentProfileCount();
959 
960   // Store the blocks to use for break and continue.
961   BreakContinueStack.push_back(BreakContinue(LoopExit, LoopCond));
962 
963   // Emit the body of the loop.
964   llvm::BasicBlock *LoopBody = createBasicBlock("do.body");
965 
966   EmitBlockWithFallThrough(LoopBody, &S);
967   {
968     RunCleanupsScope BodyScope(*this);
969     EmitStmt(S.getBody());
970   }
971 
972   EmitBlock(LoopCond.getBlock());
973 
974   // C99 6.8.5.2: "The evaluation of the controlling expression takes place
975   // after each execution of the loop body."
976 
977   // Evaluate the conditional in the while header.
978   // C99 6.8.5p2/p4: The first substatement is executed if the expression
979   // compares unequal to 0.  The condition must be a scalar type.
980   llvm::Value *BoolCondVal = EvaluateExprAsBool(S.getCond());
981 
982   BreakContinueStack.pop_back();
983 
984   // "do {} while (0)" is common in macros, avoid extra blocks.  Be sure
985   // to correctly handle break/continue though.
986   llvm::ConstantInt *C = dyn_cast<llvm::ConstantInt>(BoolCondVal);
987   bool CondIsConstInt = C;
988   bool EmitBoolCondBranch = !C || !C->isZero();
989 
990   const SourceRange &R = S.getSourceRange();
991   LoopStack.push(LoopBody, CGM.getContext(), CGM.getCodeGenOpts(), DoAttrs,
992                  SourceLocToDebugLoc(R.getBegin()),
993                  SourceLocToDebugLoc(R.getEnd()),
994                  checkIfLoopMustProgress(CondIsConstInt));
995 
996   // As long as the condition is true, iterate the loop.
997   if (EmitBoolCondBranch) {
998     uint64_t BackedgeCount = getProfileCount(S.getBody()) - ParentCount;
999     Builder.CreateCondBr(
1000         BoolCondVal, LoopBody, LoopExit.getBlock(),
1001         createProfileWeightsForLoop(S.getCond(), BackedgeCount));
1002   }
1003 
1004   LoopStack.pop();
1005 
1006   // Emit the exit block.
1007   EmitBlock(LoopExit.getBlock());
1008 
1009   // The DoCond block typically is just a branch if we skipped
1010   // emitting a branch, try to erase it.
1011   if (!EmitBoolCondBranch)
1012     SimplifyForwardingBlocks(LoopCond.getBlock());
1013 }
1014 
1015 void CodeGenFunction::EmitForStmt(const ForStmt &S,
1016                                   ArrayRef<const Attr *> ForAttrs) {
1017   JumpDest LoopExit = getJumpDestInCurrentScope("for.end");
1018 
1019   LexicalScope ForScope(*this, S.getSourceRange());
1020 
1021   // Evaluate the first part before the loop.
1022   if (S.getInit())
1023     EmitStmt(S.getInit());
1024 
1025   // Start the loop with a block that tests the condition.
1026   // If there's an increment, the continue scope will be overwritten
1027   // later.
1028   JumpDest CondDest = getJumpDestInCurrentScope("for.cond");
1029   llvm::BasicBlock *CondBlock = CondDest.getBlock();
1030   EmitBlock(CondBlock);
1031 
1032   Expr::EvalResult Result;
1033   bool CondIsConstInt =
1034       !S.getCond() || S.getCond()->EvaluateAsInt(Result, getContext());
1035 
1036   const SourceRange &R = S.getSourceRange();
1037   LoopStack.push(CondBlock, CGM.getContext(), CGM.getCodeGenOpts(), ForAttrs,
1038                  SourceLocToDebugLoc(R.getBegin()),
1039                  SourceLocToDebugLoc(R.getEnd()),
1040                  checkIfLoopMustProgress(CondIsConstInt));
1041 
1042   // Create a cleanup scope for the condition variable cleanups.
1043   LexicalScope ConditionScope(*this, S.getSourceRange());
1044 
1045   // If the for loop doesn't have an increment we can just use the condition as
1046   // the continue block. Otherwise, if there is no condition variable, we can
1047   // form the continue block now. If there is a condition variable, we can't
1048   // form the continue block until after we've emitted the condition, because
1049   // the condition is in scope in the increment, but Sema's jump diagnostics
1050   // ensure that there are no continues from the condition variable that jump
1051   // to the loop increment.
1052   JumpDest Continue;
1053   if (!S.getInc())
1054     Continue = CondDest;
1055   else if (!S.getConditionVariable())
1056     Continue = getJumpDestInCurrentScope("for.inc");
1057   BreakContinueStack.push_back(BreakContinue(LoopExit, Continue));
1058 
1059   if (S.getCond()) {
1060     // If the for statement has a condition scope, emit the local variable
1061     // declaration.
1062     if (S.getConditionVariable()) {
1063       EmitDecl(*S.getConditionVariable());
1064 
1065       // We have entered the condition variable's scope, so we're now able to
1066       // jump to the continue block.
1067       Continue = S.getInc() ? getJumpDestInCurrentScope("for.inc") : CondDest;
1068       BreakContinueStack.back().ContinueBlock = Continue;
1069     }
1070 
1071     llvm::BasicBlock *ExitBlock = LoopExit.getBlock();
1072     // If there are any cleanups between here and the loop-exit scope,
1073     // create a block to stage a loop exit along.
1074     if (ForScope.requiresCleanups())
1075       ExitBlock = createBasicBlock("for.cond.cleanup");
1076 
1077     // As long as the condition is true, iterate the loop.
1078     llvm::BasicBlock *ForBody = createBasicBlock("for.body");
1079 
1080     // C99 6.8.5p2/p4: The first substatement is executed if the expression
1081     // compares unequal to 0.  The condition must be a scalar type.
1082     llvm::Value *BoolCondVal = EvaluateExprAsBool(S.getCond());
1083     llvm::MDNode *Weights =
1084         createProfileWeightsForLoop(S.getCond(), getProfileCount(S.getBody()));
1085     if (!Weights && CGM.getCodeGenOpts().OptimizationLevel)
1086       BoolCondVal = emitCondLikelihoodViaExpectIntrinsic(
1087           BoolCondVal, Stmt::getLikelihood(S.getBody()));
1088 
1089     Builder.CreateCondBr(BoolCondVal, ForBody, ExitBlock, Weights);
1090 
1091     if (ExitBlock != LoopExit.getBlock()) {
1092       EmitBlock(ExitBlock);
1093       EmitBranchThroughCleanup(LoopExit);
1094     }
1095 
1096     EmitBlock(ForBody);
1097   } else {
1098     // Treat it as a non-zero constant.  Don't even create a new block for the
1099     // body, just fall into it.
1100   }
1101   incrementProfileCounter(&S);
1102 
1103   {
1104     // Create a separate cleanup scope for the body, in case it is not
1105     // a compound statement.
1106     RunCleanupsScope BodyScope(*this);
1107     EmitStmt(S.getBody());
1108   }
1109 
1110   // If there is an increment, emit it next.
1111   if (S.getInc()) {
1112     EmitBlock(Continue.getBlock());
1113     EmitStmt(S.getInc());
1114   }
1115 
1116   BreakContinueStack.pop_back();
1117 
1118   ConditionScope.ForceCleanup();
1119 
1120   EmitStopPoint(&S);
1121   EmitBranch(CondBlock);
1122 
1123   ForScope.ForceCleanup();
1124 
1125   LoopStack.pop();
1126 
1127   // Emit the fall-through block.
1128   EmitBlock(LoopExit.getBlock(), true);
1129 }
1130 
1131 void
1132 CodeGenFunction::EmitCXXForRangeStmt(const CXXForRangeStmt &S,
1133                                      ArrayRef<const Attr *> ForAttrs) {
1134   JumpDest LoopExit = getJumpDestInCurrentScope("for.end");
1135 
1136   LexicalScope ForScope(*this, S.getSourceRange());
1137 
1138   // Evaluate the first pieces before the loop.
1139   if (S.getInit())
1140     EmitStmt(S.getInit());
1141   EmitStmt(S.getRangeStmt());
1142   EmitStmt(S.getBeginStmt());
1143   EmitStmt(S.getEndStmt());
1144 
1145   // Start the loop with a block that tests the condition.
1146   // If there's an increment, the continue scope will be overwritten
1147   // later.
1148   llvm::BasicBlock *CondBlock = createBasicBlock("for.cond");
1149   EmitBlock(CondBlock);
1150 
1151   const SourceRange &R = S.getSourceRange();
1152   LoopStack.push(CondBlock, CGM.getContext(), CGM.getCodeGenOpts(), ForAttrs,
1153                  SourceLocToDebugLoc(R.getBegin()),
1154                  SourceLocToDebugLoc(R.getEnd()));
1155 
1156   // If there are any cleanups between here and the loop-exit scope,
1157   // create a block to stage a loop exit along.
1158   llvm::BasicBlock *ExitBlock = LoopExit.getBlock();
1159   if (ForScope.requiresCleanups())
1160     ExitBlock = createBasicBlock("for.cond.cleanup");
1161 
1162   // The loop body, consisting of the specified body and the loop variable.
1163   llvm::BasicBlock *ForBody = createBasicBlock("for.body");
1164 
1165   // The body is executed if the expression, contextually converted
1166   // to bool, is true.
1167   llvm::Value *BoolCondVal = EvaluateExprAsBool(S.getCond());
1168   llvm::MDNode *Weights =
1169       createProfileWeightsForLoop(S.getCond(), getProfileCount(S.getBody()));
1170   if (!Weights && CGM.getCodeGenOpts().OptimizationLevel)
1171     BoolCondVal = emitCondLikelihoodViaExpectIntrinsic(
1172         BoolCondVal, Stmt::getLikelihood(S.getBody()));
1173   Builder.CreateCondBr(BoolCondVal, ForBody, ExitBlock, Weights);
1174 
1175   if (ExitBlock != LoopExit.getBlock()) {
1176     EmitBlock(ExitBlock);
1177     EmitBranchThroughCleanup(LoopExit);
1178   }
1179 
1180   EmitBlock(ForBody);
1181   incrementProfileCounter(&S);
1182 
1183   // Create a block for the increment. In case of a 'continue', we jump there.
1184   JumpDest Continue = getJumpDestInCurrentScope("for.inc");
1185 
1186   // Store the blocks to use for break and continue.
1187   BreakContinueStack.push_back(BreakContinue(LoopExit, Continue));
1188 
1189   {
1190     // Create a separate cleanup scope for the loop variable and body.
1191     LexicalScope BodyScope(*this, S.getSourceRange());
1192     EmitStmt(S.getLoopVarStmt());
1193     EmitStmt(S.getBody());
1194   }
1195 
1196   EmitStopPoint(&S);
1197   // If there is an increment, emit it next.
1198   EmitBlock(Continue.getBlock());
1199   EmitStmt(S.getInc());
1200 
1201   BreakContinueStack.pop_back();
1202 
1203   EmitBranch(CondBlock);
1204 
1205   ForScope.ForceCleanup();
1206 
1207   LoopStack.pop();
1208 
1209   // Emit the fall-through block.
1210   EmitBlock(LoopExit.getBlock(), true);
1211 }
1212 
1213 void CodeGenFunction::EmitReturnOfRValue(RValue RV, QualType Ty) {
1214   if (RV.isScalar()) {
1215     Builder.CreateStore(RV.getScalarVal(), ReturnValue);
1216   } else if (RV.isAggregate()) {
1217     LValue Dest = MakeAddrLValue(ReturnValue, Ty);
1218     LValue Src = MakeAddrLValue(RV.getAggregateAddress(), Ty);
1219     EmitAggregateCopy(Dest, Src, Ty, getOverlapForReturnValue());
1220   } else {
1221     EmitStoreOfComplex(RV.getComplexVal(), MakeAddrLValue(ReturnValue, Ty),
1222                        /*init*/ true);
1223   }
1224   EmitBranchThroughCleanup(ReturnBlock);
1225 }
1226 
1227 namespace {
1228 // RAII struct used to save and restore a return statment's result expression.
1229 struct SaveRetExprRAII {
1230   SaveRetExprRAII(const Expr *RetExpr, CodeGenFunction &CGF)
1231       : OldRetExpr(CGF.RetExpr), CGF(CGF) {
1232     CGF.RetExpr = RetExpr;
1233   }
1234   ~SaveRetExprRAII() { CGF.RetExpr = OldRetExpr; }
1235   const Expr *OldRetExpr;
1236   CodeGenFunction &CGF;
1237 };
1238 } // namespace
1239 
1240 /// If we have 'return f(...);', where both caller and callee are SwiftAsync,
1241 /// codegen it as 'tail call ...; ret void;'.
1242 static void makeTailCallIfSwiftAsync(const CallExpr *CE, CGBuilderTy &Builder,
1243                                      const CGFunctionInfo *CurFnInfo) {
1244   auto calleeQualType = CE->getCallee()->getType();
1245   const FunctionType *calleeType = nullptr;
1246   if (calleeQualType->isFunctionPointerType() ||
1247       calleeQualType->isFunctionReferenceType() ||
1248       calleeQualType->isBlockPointerType() ||
1249       calleeQualType->isMemberFunctionPointerType()) {
1250     calleeType = calleeQualType->getPointeeType()->castAs<FunctionType>();
1251   } else if (auto *ty = dyn_cast<FunctionType>(calleeQualType)) {
1252     calleeType = ty;
1253   } else if (auto CMCE = dyn_cast<CXXMemberCallExpr>(CE)) {
1254     if (auto methodDecl = CMCE->getMethodDecl()) {
1255       // getMethodDecl() doesn't handle member pointers at the moment.
1256       calleeType = methodDecl->getType()->castAs<FunctionType>();
1257     } else {
1258       return;
1259     }
1260   } else {
1261     return;
1262   }
1263   if (calleeType->getCallConv() == CallingConv::CC_SwiftAsync &&
1264       (CurFnInfo->getASTCallingConvention() == CallingConv::CC_SwiftAsync)) {
1265     auto CI = cast<llvm::CallInst>(&Builder.GetInsertBlock()->back());
1266     CI->setTailCallKind(llvm::CallInst::TCK_MustTail);
1267     Builder.CreateRetVoid();
1268     Builder.ClearInsertionPoint();
1269   }
1270 }
1271 
1272 /// EmitReturnStmt - Note that due to GCC extensions, this can have an operand
1273 /// if the function returns void, or may be missing one if the function returns
1274 /// non-void.  Fun stuff :).
1275 void CodeGenFunction::EmitReturnStmt(const ReturnStmt &S) {
1276   if (requiresReturnValueCheck()) {
1277     llvm::Constant *SLoc = EmitCheckSourceLocation(S.getBeginLoc());
1278     auto *SLocPtr =
1279         new llvm::GlobalVariable(CGM.getModule(), SLoc->getType(), false,
1280                                  llvm::GlobalVariable::PrivateLinkage, SLoc);
1281     SLocPtr->setUnnamedAddr(llvm::GlobalValue::UnnamedAddr::Global);
1282     CGM.getSanitizerMetadata()->disableSanitizerForGlobal(SLocPtr);
1283     assert(ReturnLocation.isValid() && "No valid return location");
1284     Builder.CreateStore(Builder.CreateBitCast(SLocPtr, Int8PtrTy),
1285                         ReturnLocation);
1286   }
1287 
1288   // Returning from an outlined SEH helper is UB, and we already warn on it.
1289   if (IsOutlinedSEHHelper) {
1290     Builder.CreateUnreachable();
1291     Builder.ClearInsertionPoint();
1292   }
1293 
1294   // Emit the result value, even if unused, to evaluate the side effects.
1295   const Expr *RV = S.getRetValue();
1296 
1297   // Record the result expression of the return statement. The recorded
1298   // expression is used to determine whether a block capture's lifetime should
1299   // end at the end of the full expression as opposed to the end of the scope
1300   // enclosing the block expression.
1301   //
1302   // This permits a small, easily-implemented exception to our over-conservative
1303   // rules about not jumping to statements following block literals with
1304   // non-trivial cleanups.
1305   SaveRetExprRAII SaveRetExpr(RV, *this);
1306 
1307   RunCleanupsScope cleanupScope(*this);
1308   if (const auto *EWC = dyn_cast_or_null<ExprWithCleanups>(RV))
1309     RV = EWC->getSubExpr();
1310   // FIXME: Clean this up by using an LValue for ReturnTemp,
1311   // EmitStoreThroughLValue, and EmitAnyExpr.
1312   // Check if the NRVO candidate was not globalized in OpenMP mode.
1313   if (getLangOpts().ElideConstructors && S.getNRVOCandidate() &&
1314       S.getNRVOCandidate()->isNRVOVariable() &&
1315       (!getLangOpts().OpenMP ||
1316        !CGM.getOpenMPRuntime()
1317             .getAddressOfLocalVariable(*this, S.getNRVOCandidate())
1318             .isValid())) {
1319     // Apply the named return value optimization for this return statement,
1320     // which means doing nothing: the appropriate result has already been
1321     // constructed into the NRVO variable.
1322 
1323     // If there is an NRVO flag for this variable, set it to 1 into indicate
1324     // that the cleanup code should not destroy the variable.
1325     if (llvm::Value *NRVOFlag = NRVOFlags[S.getNRVOCandidate()])
1326       Builder.CreateFlagStore(Builder.getTrue(), NRVOFlag);
1327   } else if (!ReturnValue.isValid() || (RV && RV->getType()->isVoidType())) {
1328     // Make sure not to return anything, but evaluate the expression
1329     // for side effects.
1330     if (RV) {
1331       EmitAnyExpr(RV);
1332       if (auto *CE = dyn_cast<CallExpr>(RV))
1333         makeTailCallIfSwiftAsync(CE, Builder, CurFnInfo);
1334     }
1335   } else if (!RV) {
1336     // Do nothing (return value is left uninitialized)
1337   } else if (FnRetTy->isReferenceType()) {
1338     // If this function returns a reference, take the address of the expression
1339     // rather than the value.
1340     RValue Result = EmitReferenceBindingToExpr(RV);
1341     Builder.CreateStore(Result.getScalarVal(), ReturnValue);
1342   } else {
1343     switch (getEvaluationKind(RV->getType())) {
1344     case TEK_Scalar:
1345       Builder.CreateStore(EmitScalarExpr(RV), ReturnValue);
1346       break;
1347     case TEK_Complex:
1348       EmitComplexExprIntoLValue(RV, MakeAddrLValue(ReturnValue, RV->getType()),
1349                                 /*isInit*/ true);
1350       break;
1351     case TEK_Aggregate:
1352       EmitAggExpr(RV, AggValueSlot::forAddr(
1353                           ReturnValue, Qualifiers(),
1354                           AggValueSlot::IsDestructed,
1355                           AggValueSlot::DoesNotNeedGCBarriers,
1356                           AggValueSlot::IsNotAliased,
1357                           getOverlapForReturnValue()));
1358       break;
1359     }
1360   }
1361 
1362   ++NumReturnExprs;
1363   if (!RV || RV->isEvaluatable(getContext()))
1364     ++NumSimpleReturnExprs;
1365 
1366   cleanupScope.ForceCleanup();
1367   EmitBranchThroughCleanup(ReturnBlock);
1368 }
1369 
1370 void CodeGenFunction::EmitDeclStmt(const DeclStmt &S) {
1371   // As long as debug info is modeled with instructions, we have to ensure we
1372   // have a place to insert here and write the stop point here.
1373   if (HaveInsertPoint())
1374     EmitStopPoint(&S);
1375 
1376   for (const auto *I : S.decls())
1377     EmitDecl(*I);
1378 }
1379 
1380 void CodeGenFunction::EmitBreakStmt(const BreakStmt &S) {
1381   assert(!BreakContinueStack.empty() && "break stmt not in a loop or switch!");
1382 
1383   // If this code is reachable then emit a stop point (if generating
1384   // debug info). We have to do this ourselves because we are on the
1385   // "simple" statement path.
1386   if (HaveInsertPoint())
1387     EmitStopPoint(&S);
1388 
1389   EmitBranchThroughCleanup(BreakContinueStack.back().BreakBlock);
1390 }
1391 
1392 void CodeGenFunction::EmitContinueStmt(const ContinueStmt &S) {
1393   assert(!BreakContinueStack.empty() && "continue stmt not in a loop!");
1394 
1395   // If this code is reachable then emit a stop point (if generating
1396   // debug info). We have to do this ourselves because we are on the
1397   // "simple" statement path.
1398   if (HaveInsertPoint())
1399     EmitStopPoint(&S);
1400 
1401   EmitBranchThroughCleanup(BreakContinueStack.back().ContinueBlock);
1402 }
1403 
1404 /// EmitCaseStmtRange - If case statement range is not too big then
1405 /// add multiple cases to switch instruction, one for each value within
1406 /// the range. If range is too big then emit "if" condition check.
1407 void CodeGenFunction::EmitCaseStmtRange(const CaseStmt &S,
1408                                         ArrayRef<const Attr *> Attrs) {
1409   assert(S.getRHS() && "Expected RHS value in CaseStmt");
1410 
1411   llvm::APSInt LHS = S.getLHS()->EvaluateKnownConstInt(getContext());
1412   llvm::APSInt RHS = S.getRHS()->EvaluateKnownConstInt(getContext());
1413 
1414   // Emit the code for this case. We do this first to make sure it is
1415   // properly chained from our predecessor before generating the
1416   // switch machinery to enter this block.
1417   llvm::BasicBlock *CaseDest = createBasicBlock("sw.bb");
1418   EmitBlockWithFallThrough(CaseDest, &S);
1419   EmitStmt(S.getSubStmt());
1420 
1421   // If range is empty, do nothing.
1422   if (LHS.isSigned() ? RHS.slt(LHS) : RHS.ult(LHS))
1423     return;
1424 
1425   Stmt::Likelihood LH = Stmt::getLikelihood(Attrs);
1426   llvm::APInt Range = RHS - LHS;
1427   // FIXME: parameters such as this should not be hardcoded.
1428   if (Range.ult(llvm::APInt(Range.getBitWidth(), 64))) {
1429     // Range is small enough to add multiple switch instruction cases.
1430     uint64_t Total = getProfileCount(&S);
1431     unsigned NCases = Range.getZExtValue() + 1;
1432     // We only have one region counter for the entire set of cases here, so we
1433     // need to divide the weights evenly between the generated cases, ensuring
1434     // that the total weight is preserved. E.g., a weight of 5 over three cases
1435     // will be distributed as weights of 2, 2, and 1.
1436     uint64_t Weight = Total / NCases, Rem = Total % NCases;
1437     for (unsigned I = 0; I != NCases; ++I) {
1438       if (SwitchWeights)
1439         SwitchWeights->push_back(Weight + (Rem ? 1 : 0));
1440       else if (SwitchLikelihood)
1441         SwitchLikelihood->push_back(LH);
1442 
1443       if (Rem)
1444         Rem--;
1445       SwitchInsn->addCase(Builder.getInt(LHS), CaseDest);
1446       ++LHS;
1447     }
1448     return;
1449   }
1450 
1451   // The range is too big. Emit "if" condition into a new block,
1452   // making sure to save and restore the current insertion point.
1453   llvm::BasicBlock *RestoreBB = Builder.GetInsertBlock();
1454 
1455   // Push this test onto the chain of range checks (which terminates
1456   // in the default basic block). The switch's default will be changed
1457   // to the top of this chain after switch emission is complete.
1458   llvm::BasicBlock *FalseDest = CaseRangeBlock;
1459   CaseRangeBlock = createBasicBlock("sw.caserange");
1460 
1461   CurFn->getBasicBlockList().push_back(CaseRangeBlock);
1462   Builder.SetInsertPoint(CaseRangeBlock);
1463 
1464   // Emit range check.
1465   llvm::Value *Diff =
1466     Builder.CreateSub(SwitchInsn->getCondition(), Builder.getInt(LHS));
1467   llvm::Value *Cond =
1468     Builder.CreateICmpULE(Diff, Builder.getInt(Range), "inbounds");
1469 
1470   llvm::MDNode *Weights = nullptr;
1471   if (SwitchWeights) {
1472     uint64_t ThisCount = getProfileCount(&S);
1473     uint64_t DefaultCount = (*SwitchWeights)[0];
1474     Weights = createProfileWeights(ThisCount, DefaultCount);
1475 
1476     // Since we're chaining the switch default through each large case range, we
1477     // need to update the weight for the default, ie, the first case, to include
1478     // this case.
1479     (*SwitchWeights)[0] += ThisCount;
1480   } else if (SwitchLikelihood)
1481     Cond = emitCondLikelihoodViaExpectIntrinsic(Cond, LH);
1482 
1483   Builder.CreateCondBr(Cond, CaseDest, FalseDest, Weights);
1484 
1485   // Restore the appropriate insertion point.
1486   if (RestoreBB)
1487     Builder.SetInsertPoint(RestoreBB);
1488   else
1489     Builder.ClearInsertionPoint();
1490 }
1491 
1492 void CodeGenFunction::EmitCaseStmt(const CaseStmt &S,
1493                                    ArrayRef<const Attr *> Attrs) {
1494   // If there is no enclosing switch instance that we're aware of, then this
1495   // case statement and its block can be elided.  This situation only happens
1496   // when we've constant-folded the switch, are emitting the constant case,
1497   // and part of the constant case includes another case statement.  For
1498   // instance: switch (4) { case 4: do { case 5: } while (1); }
1499   if (!SwitchInsn) {
1500     EmitStmt(S.getSubStmt());
1501     return;
1502   }
1503 
1504   // Handle case ranges.
1505   if (S.getRHS()) {
1506     EmitCaseStmtRange(S, Attrs);
1507     return;
1508   }
1509 
1510   llvm::ConstantInt *CaseVal =
1511     Builder.getInt(S.getLHS()->EvaluateKnownConstInt(getContext()));
1512 
1513   // Emit debuginfo for the case value if it is an enum value.
1514   const ConstantExpr *CE;
1515   if (auto ICE = dyn_cast<ImplicitCastExpr>(S.getLHS()))
1516     CE = dyn_cast<ConstantExpr>(ICE->getSubExpr());
1517   else
1518     CE = dyn_cast<ConstantExpr>(S.getLHS());
1519   if (CE) {
1520     if (auto DE = dyn_cast<DeclRefExpr>(CE->getSubExpr()))
1521       if (CGDebugInfo *Dbg = getDebugInfo())
1522         if (CGM.getCodeGenOpts().hasReducedDebugInfo())
1523           Dbg->EmitGlobalVariable(DE->getDecl(),
1524               APValue(llvm::APSInt(CaseVal->getValue())));
1525   }
1526 
1527   if (SwitchLikelihood)
1528     SwitchLikelihood->push_back(Stmt::getLikelihood(Attrs));
1529 
1530   // If the body of the case is just a 'break', try to not emit an empty block.
1531   // If we're profiling or we're not optimizing, leave the block in for better
1532   // debug and coverage analysis.
1533   if (!CGM.getCodeGenOpts().hasProfileClangInstr() &&
1534       CGM.getCodeGenOpts().OptimizationLevel > 0 &&
1535       isa<BreakStmt>(S.getSubStmt())) {
1536     JumpDest Block = BreakContinueStack.back().BreakBlock;
1537 
1538     // Only do this optimization if there are no cleanups that need emitting.
1539     if (isObviouslyBranchWithoutCleanups(Block)) {
1540       if (SwitchWeights)
1541         SwitchWeights->push_back(getProfileCount(&S));
1542       SwitchInsn->addCase(CaseVal, Block.getBlock());
1543 
1544       // If there was a fallthrough into this case, make sure to redirect it to
1545       // the end of the switch as well.
1546       if (Builder.GetInsertBlock()) {
1547         Builder.CreateBr(Block.getBlock());
1548         Builder.ClearInsertionPoint();
1549       }
1550       return;
1551     }
1552   }
1553 
1554   llvm::BasicBlock *CaseDest = createBasicBlock("sw.bb");
1555   EmitBlockWithFallThrough(CaseDest, &S);
1556   if (SwitchWeights)
1557     SwitchWeights->push_back(getProfileCount(&S));
1558   SwitchInsn->addCase(CaseVal, CaseDest);
1559 
1560   // Recursively emitting the statement is acceptable, but is not wonderful for
1561   // code where we have many case statements nested together, i.e.:
1562   //  case 1:
1563   //    case 2:
1564   //      case 3: etc.
1565   // Handling this recursively will create a new block for each case statement
1566   // that falls through to the next case which is IR intensive.  It also causes
1567   // deep recursion which can run into stack depth limitations.  Handle
1568   // sequential non-range case statements specially.
1569   //
1570   // TODO When the next case has a likelihood attribute the code returns to the
1571   // recursive algorithm. Maybe improve this case if it becomes common practice
1572   // to use a lot of attributes.
1573   const CaseStmt *CurCase = &S;
1574   const CaseStmt *NextCase = dyn_cast<CaseStmt>(S.getSubStmt());
1575 
1576   // Otherwise, iteratively add consecutive cases to this switch stmt.
1577   while (NextCase && NextCase->getRHS() == nullptr) {
1578     CurCase = NextCase;
1579     llvm::ConstantInt *CaseVal =
1580       Builder.getInt(CurCase->getLHS()->EvaluateKnownConstInt(getContext()));
1581 
1582     if (SwitchWeights)
1583       SwitchWeights->push_back(getProfileCount(NextCase));
1584     if (CGM.getCodeGenOpts().hasProfileClangInstr()) {
1585       CaseDest = createBasicBlock("sw.bb");
1586       EmitBlockWithFallThrough(CaseDest, CurCase);
1587     }
1588     // Since this loop is only executed when the CaseStmt has no attributes
1589     // use a hard-coded value.
1590     if (SwitchLikelihood)
1591       SwitchLikelihood->push_back(Stmt::LH_None);
1592 
1593     SwitchInsn->addCase(CaseVal, CaseDest);
1594     NextCase = dyn_cast<CaseStmt>(CurCase->getSubStmt());
1595   }
1596 
1597   // Generate a stop point for debug info if the case statement is
1598   // followed by a default statement. A fallthrough case before a
1599   // default case gets its own branch target.
1600   if (CurCase->getSubStmt()->getStmtClass() == Stmt::DefaultStmtClass)
1601     EmitStopPoint(CurCase);
1602 
1603   // Normal default recursion for non-cases.
1604   EmitStmt(CurCase->getSubStmt());
1605 }
1606 
1607 void CodeGenFunction::EmitDefaultStmt(const DefaultStmt &S,
1608                                       ArrayRef<const Attr *> Attrs) {
1609   // If there is no enclosing switch instance that we're aware of, then this
1610   // default statement can be elided. This situation only happens when we've
1611   // constant-folded the switch.
1612   if (!SwitchInsn) {
1613     EmitStmt(S.getSubStmt());
1614     return;
1615   }
1616 
1617   llvm::BasicBlock *DefaultBlock = SwitchInsn->getDefaultDest();
1618   assert(DefaultBlock->empty() &&
1619          "EmitDefaultStmt: Default block already defined?");
1620 
1621   if (SwitchLikelihood)
1622     SwitchLikelihood->front() = Stmt::getLikelihood(Attrs);
1623 
1624   EmitBlockWithFallThrough(DefaultBlock, &S);
1625 
1626   EmitStmt(S.getSubStmt());
1627 }
1628 
1629 /// CollectStatementsForCase - Given the body of a 'switch' statement and a
1630 /// constant value that is being switched on, see if we can dead code eliminate
1631 /// the body of the switch to a simple series of statements to emit.  Basically,
1632 /// on a switch (5) we want to find these statements:
1633 ///    case 5:
1634 ///      printf(...);    <--
1635 ///      ++i;            <--
1636 ///      break;
1637 ///
1638 /// and add them to the ResultStmts vector.  If it is unsafe to do this
1639 /// transformation (for example, one of the elided statements contains a label
1640 /// that might be jumped to), return CSFC_Failure.  If we handled it and 'S'
1641 /// should include statements after it (e.g. the printf() line is a substmt of
1642 /// the case) then return CSFC_FallThrough.  If we handled it and found a break
1643 /// statement, then return CSFC_Success.
1644 ///
1645 /// If Case is non-null, then we are looking for the specified case, checking
1646 /// that nothing we jump over contains labels.  If Case is null, then we found
1647 /// the case and are looking for the break.
1648 ///
1649 /// If the recursive walk actually finds our Case, then we set FoundCase to
1650 /// true.
1651 ///
1652 enum CSFC_Result { CSFC_Failure, CSFC_FallThrough, CSFC_Success };
1653 static CSFC_Result CollectStatementsForCase(const Stmt *S,
1654                                             const SwitchCase *Case,
1655                                             bool &FoundCase,
1656                               SmallVectorImpl<const Stmt*> &ResultStmts) {
1657   // If this is a null statement, just succeed.
1658   if (!S)
1659     return Case ? CSFC_Success : CSFC_FallThrough;
1660 
1661   // If this is the switchcase (case 4: or default) that we're looking for, then
1662   // we're in business.  Just add the substatement.
1663   if (const SwitchCase *SC = dyn_cast<SwitchCase>(S)) {
1664     if (S == Case) {
1665       FoundCase = true;
1666       return CollectStatementsForCase(SC->getSubStmt(), nullptr, FoundCase,
1667                                       ResultStmts);
1668     }
1669 
1670     // Otherwise, this is some other case or default statement, just ignore it.
1671     return CollectStatementsForCase(SC->getSubStmt(), Case, FoundCase,
1672                                     ResultStmts);
1673   }
1674 
1675   // If we are in the live part of the code and we found our break statement,
1676   // return a success!
1677   if (!Case && isa<BreakStmt>(S))
1678     return CSFC_Success;
1679 
1680   // If this is a switch statement, then it might contain the SwitchCase, the
1681   // break, or neither.
1682   if (const CompoundStmt *CS = dyn_cast<CompoundStmt>(S)) {
1683     // Handle this as two cases: we might be looking for the SwitchCase (if so
1684     // the skipped statements must be skippable) or we might already have it.
1685     CompoundStmt::const_body_iterator I = CS->body_begin(), E = CS->body_end();
1686     bool StartedInLiveCode = FoundCase;
1687     unsigned StartSize = ResultStmts.size();
1688 
1689     // If we've not found the case yet, scan through looking for it.
1690     if (Case) {
1691       // Keep track of whether we see a skipped declaration.  The code could be
1692       // using the declaration even if it is skipped, so we can't optimize out
1693       // the decl if the kept statements might refer to it.
1694       bool HadSkippedDecl = false;
1695 
1696       // If we're looking for the case, just see if we can skip each of the
1697       // substatements.
1698       for (; Case && I != E; ++I) {
1699         HadSkippedDecl |= CodeGenFunction::mightAddDeclToScope(*I);
1700 
1701         switch (CollectStatementsForCase(*I, Case, FoundCase, ResultStmts)) {
1702         case CSFC_Failure: return CSFC_Failure;
1703         case CSFC_Success:
1704           // A successful result means that either 1) that the statement doesn't
1705           // have the case and is skippable, or 2) does contain the case value
1706           // and also contains the break to exit the switch.  In the later case,
1707           // we just verify the rest of the statements are elidable.
1708           if (FoundCase) {
1709             // If we found the case and skipped declarations, we can't do the
1710             // optimization.
1711             if (HadSkippedDecl)
1712               return CSFC_Failure;
1713 
1714             for (++I; I != E; ++I)
1715               if (CodeGenFunction::ContainsLabel(*I, true))
1716                 return CSFC_Failure;
1717             return CSFC_Success;
1718           }
1719           break;
1720         case CSFC_FallThrough:
1721           // If we have a fallthrough condition, then we must have found the
1722           // case started to include statements.  Consider the rest of the
1723           // statements in the compound statement as candidates for inclusion.
1724           assert(FoundCase && "Didn't find case but returned fallthrough?");
1725           // We recursively found Case, so we're not looking for it anymore.
1726           Case = nullptr;
1727 
1728           // If we found the case and skipped declarations, we can't do the
1729           // optimization.
1730           if (HadSkippedDecl)
1731             return CSFC_Failure;
1732           break;
1733         }
1734       }
1735 
1736       if (!FoundCase)
1737         return CSFC_Success;
1738 
1739       assert(!HadSkippedDecl && "fallthrough after skipping decl");
1740     }
1741 
1742     // If we have statements in our range, then we know that the statements are
1743     // live and need to be added to the set of statements we're tracking.
1744     bool AnyDecls = false;
1745     for (; I != E; ++I) {
1746       AnyDecls |= CodeGenFunction::mightAddDeclToScope(*I);
1747 
1748       switch (CollectStatementsForCase(*I, nullptr, FoundCase, ResultStmts)) {
1749       case CSFC_Failure: return CSFC_Failure;
1750       case CSFC_FallThrough:
1751         // A fallthrough result means that the statement was simple and just
1752         // included in ResultStmt, keep adding them afterwards.
1753         break;
1754       case CSFC_Success:
1755         // A successful result means that we found the break statement and
1756         // stopped statement inclusion.  We just ensure that any leftover stmts
1757         // are skippable and return success ourselves.
1758         for (++I; I != E; ++I)
1759           if (CodeGenFunction::ContainsLabel(*I, true))
1760             return CSFC_Failure;
1761         return CSFC_Success;
1762       }
1763     }
1764 
1765     // If we're about to fall out of a scope without hitting a 'break;', we
1766     // can't perform the optimization if there were any decls in that scope
1767     // (we'd lose their end-of-lifetime).
1768     if (AnyDecls) {
1769       // If the entire compound statement was live, there's one more thing we
1770       // can try before giving up: emit the whole thing as a single statement.
1771       // We can do that unless the statement contains a 'break;'.
1772       // FIXME: Such a break must be at the end of a construct within this one.
1773       // We could emit this by just ignoring the BreakStmts entirely.
1774       if (StartedInLiveCode && !CodeGenFunction::containsBreak(S)) {
1775         ResultStmts.resize(StartSize);
1776         ResultStmts.push_back(S);
1777       } else {
1778         return CSFC_Failure;
1779       }
1780     }
1781 
1782     return CSFC_FallThrough;
1783   }
1784 
1785   // Okay, this is some other statement that we don't handle explicitly, like a
1786   // for statement or increment etc.  If we are skipping over this statement,
1787   // just verify it doesn't have labels, which would make it invalid to elide.
1788   if (Case) {
1789     if (CodeGenFunction::ContainsLabel(S, true))
1790       return CSFC_Failure;
1791     return CSFC_Success;
1792   }
1793 
1794   // Otherwise, we want to include this statement.  Everything is cool with that
1795   // so long as it doesn't contain a break out of the switch we're in.
1796   if (CodeGenFunction::containsBreak(S)) return CSFC_Failure;
1797 
1798   // Otherwise, everything is great.  Include the statement and tell the caller
1799   // that we fall through and include the next statement as well.
1800   ResultStmts.push_back(S);
1801   return CSFC_FallThrough;
1802 }
1803 
1804 /// FindCaseStatementsForValue - Find the case statement being jumped to and
1805 /// then invoke CollectStatementsForCase to find the list of statements to emit
1806 /// for a switch on constant.  See the comment above CollectStatementsForCase
1807 /// for more details.
1808 static bool FindCaseStatementsForValue(const SwitchStmt &S,
1809                                        const llvm::APSInt &ConstantCondValue,
1810                                 SmallVectorImpl<const Stmt*> &ResultStmts,
1811                                        ASTContext &C,
1812                                        const SwitchCase *&ResultCase) {
1813   // First step, find the switch case that is being branched to.  We can do this
1814   // efficiently by scanning the SwitchCase list.
1815   const SwitchCase *Case = S.getSwitchCaseList();
1816   const DefaultStmt *DefaultCase = nullptr;
1817 
1818   for (; Case; Case = Case->getNextSwitchCase()) {
1819     // It's either a default or case.  Just remember the default statement in
1820     // case we're not jumping to any numbered cases.
1821     if (const DefaultStmt *DS = dyn_cast<DefaultStmt>(Case)) {
1822       DefaultCase = DS;
1823       continue;
1824     }
1825 
1826     // Check to see if this case is the one we're looking for.
1827     const CaseStmt *CS = cast<CaseStmt>(Case);
1828     // Don't handle case ranges yet.
1829     if (CS->getRHS()) return false;
1830 
1831     // If we found our case, remember it as 'case'.
1832     if (CS->getLHS()->EvaluateKnownConstInt(C) == ConstantCondValue)
1833       break;
1834   }
1835 
1836   // If we didn't find a matching case, we use a default if it exists, or we
1837   // elide the whole switch body!
1838   if (!Case) {
1839     // It is safe to elide the body of the switch if it doesn't contain labels
1840     // etc.  If it is safe, return successfully with an empty ResultStmts list.
1841     if (!DefaultCase)
1842       return !CodeGenFunction::ContainsLabel(&S);
1843     Case = DefaultCase;
1844   }
1845 
1846   // Ok, we know which case is being jumped to, try to collect all the
1847   // statements that follow it.  This can fail for a variety of reasons.  Also,
1848   // check to see that the recursive walk actually found our case statement.
1849   // Insane cases like this can fail to find it in the recursive walk since we
1850   // don't handle every stmt kind:
1851   // switch (4) {
1852   //   while (1) {
1853   //     case 4: ...
1854   bool FoundCase = false;
1855   ResultCase = Case;
1856   return CollectStatementsForCase(S.getBody(), Case, FoundCase,
1857                                   ResultStmts) != CSFC_Failure &&
1858          FoundCase;
1859 }
1860 
1861 static Optional<SmallVector<uint64_t, 16>>
1862 getLikelihoodWeights(ArrayRef<Stmt::Likelihood> Likelihoods) {
1863   // Are there enough branches to weight them?
1864   if (Likelihoods.size() <= 1)
1865     return None;
1866 
1867   uint64_t NumUnlikely = 0;
1868   uint64_t NumNone = 0;
1869   uint64_t NumLikely = 0;
1870   for (const auto LH : Likelihoods) {
1871     switch (LH) {
1872     case Stmt::LH_Unlikely:
1873       ++NumUnlikely;
1874       break;
1875     case Stmt::LH_None:
1876       ++NumNone;
1877       break;
1878     case Stmt::LH_Likely:
1879       ++NumLikely;
1880       break;
1881     }
1882   }
1883 
1884   // Is there a likelihood attribute used?
1885   if (NumUnlikely == 0 && NumLikely == 0)
1886     return None;
1887 
1888   // When multiple cases share the same code they can be combined during
1889   // optimization. In that case the weights of the branch will be the sum of
1890   // the individual weights. Make sure the combined sum of all neutral cases
1891   // doesn't exceed the value of a single likely attribute.
1892   // The additions both avoid divisions by 0 and make sure the weights of None
1893   // don't exceed the weight of Likely.
1894   const uint64_t Likely = INT32_MAX / (NumLikely + 2);
1895   const uint64_t None = Likely / (NumNone + 1);
1896   const uint64_t Unlikely = 0;
1897 
1898   SmallVector<uint64_t, 16> Result;
1899   Result.reserve(Likelihoods.size());
1900   for (const auto LH : Likelihoods) {
1901     switch (LH) {
1902     case Stmt::LH_Unlikely:
1903       Result.push_back(Unlikely);
1904       break;
1905     case Stmt::LH_None:
1906       Result.push_back(None);
1907       break;
1908     case Stmt::LH_Likely:
1909       Result.push_back(Likely);
1910       break;
1911     }
1912   }
1913 
1914   return Result;
1915 }
1916 
1917 void CodeGenFunction::EmitSwitchStmt(const SwitchStmt &S) {
1918   // Handle nested switch statements.
1919   llvm::SwitchInst *SavedSwitchInsn = SwitchInsn;
1920   SmallVector<uint64_t, 16> *SavedSwitchWeights = SwitchWeights;
1921   SmallVector<Stmt::Likelihood, 16> *SavedSwitchLikelihood = SwitchLikelihood;
1922   llvm::BasicBlock *SavedCRBlock = CaseRangeBlock;
1923 
1924   // See if we can constant fold the condition of the switch and therefore only
1925   // emit the live case statement (if any) of the switch.
1926   llvm::APSInt ConstantCondValue;
1927   if (ConstantFoldsToSimpleInteger(S.getCond(), ConstantCondValue)) {
1928     SmallVector<const Stmt*, 4> CaseStmts;
1929     const SwitchCase *Case = nullptr;
1930     if (FindCaseStatementsForValue(S, ConstantCondValue, CaseStmts,
1931                                    getContext(), Case)) {
1932       if (Case)
1933         incrementProfileCounter(Case);
1934       RunCleanupsScope ExecutedScope(*this);
1935 
1936       if (S.getInit())
1937         EmitStmt(S.getInit());
1938 
1939       // Emit the condition variable if needed inside the entire cleanup scope
1940       // used by this special case for constant folded switches.
1941       if (S.getConditionVariable())
1942         EmitDecl(*S.getConditionVariable());
1943 
1944       // At this point, we are no longer "within" a switch instance, so
1945       // we can temporarily enforce this to ensure that any embedded case
1946       // statements are not emitted.
1947       SwitchInsn = nullptr;
1948 
1949       // Okay, we can dead code eliminate everything except this case.  Emit the
1950       // specified series of statements and we're good.
1951       for (unsigned i = 0, e = CaseStmts.size(); i != e; ++i)
1952         EmitStmt(CaseStmts[i]);
1953       incrementProfileCounter(&S);
1954 
1955       // Now we want to restore the saved switch instance so that nested
1956       // switches continue to function properly
1957       SwitchInsn = SavedSwitchInsn;
1958 
1959       return;
1960     }
1961   }
1962 
1963   JumpDest SwitchExit = getJumpDestInCurrentScope("sw.epilog");
1964 
1965   RunCleanupsScope ConditionScope(*this);
1966 
1967   if (S.getInit())
1968     EmitStmt(S.getInit());
1969 
1970   if (S.getConditionVariable())
1971     EmitDecl(*S.getConditionVariable());
1972   llvm::Value *CondV = EmitScalarExpr(S.getCond());
1973 
1974   // Create basic block to hold stuff that comes after switch
1975   // statement. We also need to create a default block now so that
1976   // explicit case ranges tests can have a place to jump to on
1977   // failure.
1978   llvm::BasicBlock *DefaultBlock = createBasicBlock("sw.default");
1979   SwitchInsn = Builder.CreateSwitch(CondV, DefaultBlock);
1980   if (PGO.haveRegionCounts()) {
1981     // Walk the SwitchCase list to find how many there are.
1982     uint64_t DefaultCount = 0;
1983     unsigned NumCases = 0;
1984     for (const SwitchCase *Case = S.getSwitchCaseList();
1985          Case;
1986          Case = Case->getNextSwitchCase()) {
1987       if (isa<DefaultStmt>(Case))
1988         DefaultCount = getProfileCount(Case);
1989       NumCases += 1;
1990     }
1991     SwitchWeights = new SmallVector<uint64_t, 16>();
1992     SwitchWeights->reserve(NumCases);
1993     // The default needs to be first. We store the edge count, so we already
1994     // know the right weight.
1995     SwitchWeights->push_back(DefaultCount);
1996   } else if (CGM.getCodeGenOpts().OptimizationLevel) {
1997     SwitchLikelihood = new SmallVector<Stmt::Likelihood, 16>();
1998     // Initialize the default case.
1999     SwitchLikelihood->push_back(Stmt::LH_None);
2000   }
2001 
2002   CaseRangeBlock = DefaultBlock;
2003 
2004   // Clear the insertion point to indicate we are in unreachable code.
2005   Builder.ClearInsertionPoint();
2006 
2007   // All break statements jump to NextBlock. If BreakContinueStack is non-empty
2008   // then reuse last ContinueBlock.
2009   JumpDest OuterContinue;
2010   if (!BreakContinueStack.empty())
2011     OuterContinue = BreakContinueStack.back().ContinueBlock;
2012 
2013   BreakContinueStack.push_back(BreakContinue(SwitchExit, OuterContinue));
2014 
2015   // Emit switch body.
2016   EmitStmt(S.getBody());
2017 
2018   BreakContinueStack.pop_back();
2019 
2020   // Update the default block in case explicit case range tests have
2021   // been chained on top.
2022   SwitchInsn->setDefaultDest(CaseRangeBlock);
2023 
2024   // If a default was never emitted:
2025   if (!DefaultBlock->getParent()) {
2026     // If we have cleanups, emit the default block so that there's a
2027     // place to jump through the cleanups from.
2028     if (ConditionScope.requiresCleanups()) {
2029       EmitBlock(DefaultBlock);
2030 
2031     // Otherwise, just forward the default block to the switch end.
2032     } else {
2033       DefaultBlock->replaceAllUsesWith(SwitchExit.getBlock());
2034       delete DefaultBlock;
2035     }
2036   }
2037 
2038   ConditionScope.ForceCleanup();
2039 
2040   // Emit continuation.
2041   EmitBlock(SwitchExit.getBlock(), true);
2042   incrementProfileCounter(&S);
2043 
2044   // If the switch has a condition wrapped by __builtin_unpredictable,
2045   // create metadata that specifies that the switch is unpredictable.
2046   // Don't bother if not optimizing because that metadata would not be used.
2047   auto *Call = dyn_cast<CallExpr>(S.getCond());
2048   if (Call && CGM.getCodeGenOpts().OptimizationLevel != 0) {
2049     auto *FD = dyn_cast_or_null<FunctionDecl>(Call->getCalleeDecl());
2050     if (FD && FD->getBuiltinID() == Builtin::BI__builtin_unpredictable) {
2051       llvm::MDBuilder MDHelper(getLLVMContext());
2052       SwitchInsn->setMetadata(llvm::LLVMContext::MD_unpredictable,
2053                               MDHelper.createUnpredictable());
2054     }
2055   }
2056 
2057   if (SwitchWeights) {
2058     assert(SwitchWeights->size() == 1 + SwitchInsn->getNumCases() &&
2059            "switch weights do not match switch cases");
2060     // If there's only one jump destination there's no sense weighting it.
2061     if (SwitchWeights->size() > 1)
2062       SwitchInsn->setMetadata(llvm::LLVMContext::MD_prof,
2063                               createProfileWeights(*SwitchWeights));
2064     delete SwitchWeights;
2065   } else if (SwitchLikelihood) {
2066     assert(SwitchLikelihood->size() == 1 + SwitchInsn->getNumCases() &&
2067            "switch likelihoods do not match switch cases");
2068     Optional<SmallVector<uint64_t, 16>> LHW =
2069         getLikelihoodWeights(*SwitchLikelihood);
2070     if (LHW) {
2071       llvm::MDBuilder MDHelper(CGM.getLLVMContext());
2072       SwitchInsn->setMetadata(llvm::LLVMContext::MD_prof,
2073                               createProfileWeights(*LHW));
2074     }
2075     delete SwitchLikelihood;
2076   }
2077   SwitchInsn = SavedSwitchInsn;
2078   SwitchWeights = SavedSwitchWeights;
2079   SwitchLikelihood = SavedSwitchLikelihood;
2080   CaseRangeBlock = SavedCRBlock;
2081 }
2082 
2083 static std::string
2084 SimplifyConstraint(const char *Constraint, const TargetInfo &Target,
2085                  SmallVectorImpl<TargetInfo::ConstraintInfo> *OutCons=nullptr) {
2086   std::string Result;
2087 
2088   while (*Constraint) {
2089     switch (*Constraint) {
2090     default:
2091       Result += Target.convertConstraint(Constraint);
2092       break;
2093     // Ignore these
2094     case '*':
2095     case '?':
2096     case '!':
2097     case '=': // Will see this and the following in mult-alt constraints.
2098     case '+':
2099       break;
2100     case '#': // Ignore the rest of the constraint alternative.
2101       while (Constraint[1] && Constraint[1] != ',')
2102         Constraint++;
2103       break;
2104     case '&':
2105     case '%':
2106       Result += *Constraint;
2107       while (Constraint[1] && Constraint[1] == *Constraint)
2108         Constraint++;
2109       break;
2110     case ',':
2111       Result += "|";
2112       break;
2113     case 'g':
2114       Result += "imr";
2115       break;
2116     case '[': {
2117       assert(OutCons &&
2118              "Must pass output names to constraints with a symbolic name");
2119       unsigned Index;
2120       bool result = Target.resolveSymbolicName(Constraint, *OutCons, Index);
2121       assert(result && "Could not resolve symbolic name"); (void)result;
2122       Result += llvm::utostr(Index);
2123       break;
2124     }
2125     }
2126 
2127     Constraint++;
2128   }
2129 
2130   return Result;
2131 }
2132 
2133 /// AddVariableConstraints - Look at AsmExpr and if it is a variable declared
2134 /// as using a particular register add that as a constraint that will be used
2135 /// in this asm stmt.
2136 static std::string
2137 AddVariableConstraints(const std::string &Constraint, const Expr &AsmExpr,
2138                        const TargetInfo &Target, CodeGenModule &CGM,
2139                        const AsmStmt &Stmt, const bool EarlyClobber,
2140                        std::string *GCCReg = nullptr) {
2141   const DeclRefExpr *AsmDeclRef = dyn_cast<DeclRefExpr>(&AsmExpr);
2142   if (!AsmDeclRef)
2143     return Constraint;
2144   const ValueDecl &Value = *AsmDeclRef->getDecl();
2145   const VarDecl *Variable = dyn_cast<VarDecl>(&Value);
2146   if (!Variable)
2147     return Constraint;
2148   if (Variable->getStorageClass() != SC_Register)
2149     return Constraint;
2150   AsmLabelAttr *Attr = Variable->getAttr<AsmLabelAttr>();
2151   if (!Attr)
2152     return Constraint;
2153   StringRef Register = Attr->getLabel();
2154   assert(Target.isValidGCCRegisterName(Register));
2155   // We're using validateOutputConstraint here because we only care if
2156   // this is a register constraint.
2157   TargetInfo::ConstraintInfo Info(Constraint, "");
2158   if (Target.validateOutputConstraint(Info) &&
2159       !Info.allowsRegister()) {
2160     CGM.ErrorUnsupported(&Stmt, "__asm__");
2161     return Constraint;
2162   }
2163   // Canonicalize the register here before returning it.
2164   Register = Target.getNormalizedGCCRegisterName(Register);
2165   if (GCCReg != nullptr)
2166     *GCCReg = Register.str();
2167   return (EarlyClobber ? "&{" : "{") + Register.str() + "}";
2168 }
2169 
2170 std::pair<llvm::Value*, llvm::Type *> CodeGenFunction::EmitAsmInputLValue(
2171     const TargetInfo::ConstraintInfo &Info, LValue InputValue,
2172     QualType InputType, std::string &ConstraintStr, SourceLocation Loc) {
2173   if (Info.allowsRegister() || !Info.allowsMemory()) {
2174     if (CodeGenFunction::hasScalarEvaluationKind(InputType))
2175       return {EmitLoadOfLValue(InputValue, Loc).getScalarVal(), nullptr};
2176 
2177     llvm::Type *Ty = ConvertType(InputType);
2178     uint64_t Size = CGM.getDataLayout().getTypeSizeInBits(Ty);
2179     if ((Size <= 64 && llvm::isPowerOf2_64(Size)) ||
2180         getTargetHooks().isScalarizableAsmOperand(*this, Ty)) {
2181       Ty = llvm::IntegerType::get(getLLVMContext(), Size);
2182 
2183       return {Builder.CreateLoad(Builder.CreateElementBitCast(
2184                   InputValue.getAddress(*this), Ty)),
2185               nullptr};
2186     }
2187   }
2188 
2189   Address Addr = InputValue.getAddress(*this);
2190   ConstraintStr += '*';
2191   return {Addr.getPointer(), Addr.getElementType()};
2192 }
2193 
2194 std::pair<llvm::Value *, llvm::Type *>
2195 CodeGenFunction::EmitAsmInput(const TargetInfo::ConstraintInfo &Info,
2196                               const Expr *InputExpr,
2197                               std::string &ConstraintStr) {
2198   // If this can't be a register or memory, i.e., has to be a constant
2199   // (immediate or symbolic), try to emit it as such.
2200   if (!Info.allowsRegister() && !Info.allowsMemory()) {
2201     if (Info.requiresImmediateConstant()) {
2202       Expr::EvalResult EVResult;
2203       InputExpr->EvaluateAsRValue(EVResult, getContext(), true);
2204 
2205       llvm::APSInt IntResult;
2206       if (EVResult.Val.toIntegralConstant(IntResult, InputExpr->getType(),
2207                                           getContext()))
2208         return {llvm::ConstantInt::get(getLLVMContext(), IntResult), nullptr};
2209     }
2210 
2211     Expr::EvalResult Result;
2212     if (InputExpr->EvaluateAsInt(Result, getContext()))
2213       return {llvm::ConstantInt::get(getLLVMContext(), Result.Val.getInt()),
2214               nullptr};
2215   }
2216 
2217   if (Info.allowsRegister() || !Info.allowsMemory())
2218     if (CodeGenFunction::hasScalarEvaluationKind(InputExpr->getType()))
2219       return {EmitScalarExpr(InputExpr), nullptr};
2220   if (InputExpr->getStmtClass() == Expr::CXXThisExprClass)
2221     return {EmitScalarExpr(InputExpr), nullptr};
2222   InputExpr = InputExpr->IgnoreParenNoopCasts(getContext());
2223   LValue Dest = EmitLValue(InputExpr);
2224   return EmitAsmInputLValue(Info, Dest, InputExpr->getType(), ConstraintStr,
2225                             InputExpr->getExprLoc());
2226 }
2227 
2228 /// getAsmSrcLocInfo - Return the !srcloc metadata node to attach to an inline
2229 /// asm call instruction.  The !srcloc MDNode contains a list of constant
2230 /// integers which are the source locations of the start of each line in the
2231 /// asm.
2232 static llvm::MDNode *getAsmSrcLocInfo(const StringLiteral *Str,
2233                                       CodeGenFunction &CGF) {
2234   SmallVector<llvm::Metadata *, 8> Locs;
2235   // Add the location of the first line to the MDNode.
2236   Locs.push_back(llvm::ConstantAsMetadata::get(llvm::ConstantInt::get(
2237       CGF.Int64Ty, Str->getBeginLoc().getRawEncoding())));
2238   StringRef StrVal = Str->getString();
2239   if (!StrVal.empty()) {
2240     const SourceManager &SM = CGF.CGM.getContext().getSourceManager();
2241     const LangOptions &LangOpts = CGF.CGM.getLangOpts();
2242     unsigned StartToken = 0;
2243     unsigned ByteOffset = 0;
2244 
2245     // Add the location of the start of each subsequent line of the asm to the
2246     // MDNode.
2247     for (unsigned i = 0, e = StrVal.size() - 1; i != e; ++i) {
2248       if (StrVal[i] != '\n') continue;
2249       SourceLocation LineLoc = Str->getLocationOfByte(
2250           i + 1, SM, LangOpts, CGF.getTarget(), &StartToken, &ByteOffset);
2251       Locs.push_back(llvm::ConstantAsMetadata::get(
2252           llvm::ConstantInt::get(CGF.Int64Ty, LineLoc.getRawEncoding())));
2253     }
2254   }
2255 
2256   return llvm::MDNode::get(CGF.getLLVMContext(), Locs);
2257 }
2258 
2259 static void UpdateAsmCallInst(llvm::CallBase &Result, bool HasSideEffect,
2260                               bool HasUnwindClobber, bool ReadOnly,
2261                               bool ReadNone, bool NoMerge, const AsmStmt &S,
2262                               const std::vector<llvm::Type *> &ResultRegTypes,
2263                               const std::vector<llvm::Type *> &ArgElemTypes,
2264                               CodeGenFunction &CGF,
2265                               std::vector<llvm::Value *> &RegResults) {
2266   if (!HasUnwindClobber)
2267     Result.addFnAttr(llvm::Attribute::NoUnwind);
2268 
2269   if (NoMerge)
2270     Result.addFnAttr(llvm::Attribute::NoMerge);
2271   // Attach readnone and readonly attributes.
2272   if (!HasSideEffect) {
2273     if (ReadNone)
2274       Result.addFnAttr(llvm::Attribute::ReadNone);
2275     else if (ReadOnly)
2276       Result.addFnAttr(llvm::Attribute::ReadOnly);
2277   }
2278 
2279   // Add elementtype attribute for indirect constraints.
2280   for (auto Pair : llvm::enumerate(ArgElemTypes)) {
2281     if (Pair.value()) {
2282       auto Attr = llvm::Attribute::get(
2283           CGF.getLLVMContext(), llvm::Attribute::ElementType, Pair.value());
2284       Result.addParamAttr(Pair.index(), Attr);
2285     }
2286   }
2287 
2288   // Slap the source location of the inline asm into a !srcloc metadata on the
2289   // call.
2290   if (const auto *gccAsmStmt = dyn_cast<GCCAsmStmt>(&S))
2291     Result.setMetadata("srcloc",
2292                        getAsmSrcLocInfo(gccAsmStmt->getAsmString(), CGF));
2293   else {
2294     // At least put the line number on MS inline asm blobs.
2295     llvm::Constant *Loc =
2296         llvm::ConstantInt::get(CGF.Int64Ty, S.getAsmLoc().getRawEncoding());
2297     Result.setMetadata("srcloc",
2298                        llvm::MDNode::get(CGF.getLLVMContext(),
2299                                          llvm::ConstantAsMetadata::get(Loc)));
2300   }
2301 
2302   if (CGF.getLangOpts().assumeFunctionsAreConvergent())
2303     // Conservatively, mark all inline asm blocks in CUDA or OpenCL as
2304     // convergent (meaning, they may call an intrinsically convergent op, such
2305     // as bar.sync, and so can't have certain optimizations applied around
2306     // them).
2307     Result.addFnAttr(llvm::Attribute::Convergent);
2308   // Extract all of the register value results from the asm.
2309   if (ResultRegTypes.size() == 1) {
2310     RegResults.push_back(&Result);
2311   } else {
2312     for (unsigned i = 0, e = ResultRegTypes.size(); i != e; ++i) {
2313       llvm::Value *Tmp = CGF.Builder.CreateExtractValue(&Result, i, "asmresult");
2314       RegResults.push_back(Tmp);
2315     }
2316   }
2317 }
2318 
2319 void CodeGenFunction::EmitAsmStmt(const AsmStmt &S) {
2320   // Pop all cleanup blocks at the end of the asm statement.
2321   CodeGenFunction::RunCleanupsScope Cleanups(*this);
2322 
2323   // Assemble the final asm string.
2324   std::string AsmString = S.generateAsmString(getContext());
2325 
2326   // Get all the output and input constraints together.
2327   SmallVector<TargetInfo::ConstraintInfo, 4> OutputConstraintInfos;
2328   SmallVector<TargetInfo::ConstraintInfo, 4> InputConstraintInfos;
2329 
2330   for (unsigned i = 0, e = S.getNumOutputs(); i != e; i++) {
2331     StringRef Name;
2332     if (const GCCAsmStmt *GAS = dyn_cast<GCCAsmStmt>(&S))
2333       Name = GAS->getOutputName(i);
2334     TargetInfo::ConstraintInfo Info(S.getOutputConstraint(i), Name);
2335     bool IsValid = getTarget().validateOutputConstraint(Info); (void)IsValid;
2336     assert(IsValid && "Failed to parse output constraint");
2337     OutputConstraintInfos.push_back(Info);
2338   }
2339 
2340   for (unsigned i = 0, e = S.getNumInputs(); i != e; i++) {
2341     StringRef Name;
2342     if (const GCCAsmStmt *GAS = dyn_cast<GCCAsmStmt>(&S))
2343       Name = GAS->getInputName(i);
2344     TargetInfo::ConstraintInfo Info(S.getInputConstraint(i), Name);
2345     bool IsValid =
2346       getTarget().validateInputConstraint(OutputConstraintInfos, Info);
2347     assert(IsValid && "Failed to parse input constraint"); (void)IsValid;
2348     InputConstraintInfos.push_back(Info);
2349   }
2350 
2351   std::string Constraints;
2352 
2353   std::vector<LValue> ResultRegDests;
2354   std::vector<QualType> ResultRegQualTys;
2355   std::vector<llvm::Type *> ResultRegTypes;
2356   std::vector<llvm::Type *> ResultTruncRegTypes;
2357   std::vector<llvm::Type *> ArgTypes;
2358   std::vector<llvm::Type *> ArgElemTypes;
2359   std::vector<llvm::Value*> Args;
2360   llvm::BitVector ResultTypeRequiresCast;
2361   llvm::BitVector ResultRegIsFlagReg;
2362 
2363   // Keep track of inout constraints.
2364   std::string InOutConstraints;
2365   std::vector<llvm::Value*> InOutArgs;
2366   std::vector<llvm::Type*> InOutArgTypes;
2367   std::vector<llvm::Type*> InOutArgElemTypes;
2368 
2369   // Keep track of out constraints for tied input operand.
2370   std::vector<std::string> OutputConstraints;
2371 
2372   // Keep track of defined physregs.
2373   llvm::SmallSet<std::string, 8> PhysRegOutputs;
2374 
2375   // An inline asm can be marked readonly if it meets the following conditions:
2376   //  - it doesn't have any sideeffects
2377   //  - it doesn't clobber memory
2378   //  - it doesn't return a value by-reference
2379   // It can be marked readnone if it doesn't have any input memory constraints
2380   // in addition to meeting the conditions listed above.
2381   bool ReadOnly = true, ReadNone = true;
2382 
2383   for (unsigned i = 0, e = S.getNumOutputs(); i != e; i++) {
2384     TargetInfo::ConstraintInfo &Info = OutputConstraintInfos[i];
2385 
2386     // Simplify the output constraint.
2387     std::string OutputConstraint(S.getOutputConstraint(i));
2388     OutputConstraint = SimplifyConstraint(OutputConstraint.c_str() + 1,
2389                                           getTarget(), &OutputConstraintInfos);
2390 
2391     const Expr *OutExpr = S.getOutputExpr(i);
2392     OutExpr = OutExpr->IgnoreParenNoopCasts(getContext());
2393 
2394     std::string GCCReg;
2395     OutputConstraint = AddVariableConstraints(OutputConstraint, *OutExpr,
2396                                               getTarget(), CGM, S,
2397                                               Info.earlyClobber(),
2398                                               &GCCReg);
2399     // Give an error on multiple outputs to same physreg.
2400     if (!GCCReg.empty() && !PhysRegOutputs.insert(GCCReg).second)
2401       CGM.Error(S.getAsmLoc(), "multiple outputs to hard register: " + GCCReg);
2402 
2403     OutputConstraints.push_back(OutputConstraint);
2404     LValue Dest = EmitLValue(OutExpr);
2405     if (!Constraints.empty())
2406       Constraints += ',';
2407 
2408     // If this is a register output, then make the inline asm return it
2409     // by-value.  If this is a memory result, return the value by-reference.
2410     QualType QTy = OutExpr->getType();
2411     const bool IsScalarOrAggregate = hasScalarEvaluationKind(QTy) ||
2412                                      hasAggregateEvaluationKind(QTy);
2413     if (!Info.allowsMemory() && IsScalarOrAggregate) {
2414 
2415       Constraints += "=" + OutputConstraint;
2416       ResultRegQualTys.push_back(QTy);
2417       ResultRegDests.push_back(Dest);
2418 
2419       bool IsFlagReg = llvm::StringRef(OutputConstraint).startswith("{@cc");
2420       ResultRegIsFlagReg.push_back(IsFlagReg);
2421 
2422       llvm::Type *Ty = ConvertTypeForMem(QTy);
2423       const bool RequiresCast = Info.allowsRegister() &&
2424           (getTargetHooks().isScalarizableAsmOperand(*this, Ty) ||
2425            Ty->isAggregateType());
2426 
2427       ResultTruncRegTypes.push_back(Ty);
2428       ResultTypeRequiresCast.push_back(RequiresCast);
2429 
2430       if (RequiresCast) {
2431         unsigned Size = getContext().getTypeSize(QTy);
2432         Ty = llvm::IntegerType::get(getLLVMContext(), Size);
2433       }
2434       ResultRegTypes.push_back(Ty);
2435       // If this output is tied to an input, and if the input is larger, then
2436       // we need to set the actual result type of the inline asm node to be the
2437       // same as the input type.
2438       if (Info.hasMatchingInput()) {
2439         unsigned InputNo;
2440         for (InputNo = 0; InputNo != S.getNumInputs(); ++InputNo) {
2441           TargetInfo::ConstraintInfo &Input = InputConstraintInfos[InputNo];
2442           if (Input.hasTiedOperand() && Input.getTiedOperand() == i)
2443             break;
2444         }
2445         assert(InputNo != S.getNumInputs() && "Didn't find matching input!");
2446 
2447         QualType InputTy = S.getInputExpr(InputNo)->getType();
2448         QualType OutputType = OutExpr->getType();
2449 
2450         uint64_t InputSize = getContext().getTypeSize(InputTy);
2451         if (getContext().getTypeSize(OutputType) < InputSize) {
2452           // Form the asm to return the value as a larger integer or fp type.
2453           ResultRegTypes.back() = ConvertType(InputTy);
2454         }
2455       }
2456       if (llvm::Type* AdjTy =
2457             getTargetHooks().adjustInlineAsmType(*this, OutputConstraint,
2458                                                  ResultRegTypes.back()))
2459         ResultRegTypes.back() = AdjTy;
2460       else {
2461         CGM.getDiags().Report(S.getAsmLoc(),
2462                               diag::err_asm_invalid_type_in_input)
2463             << OutExpr->getType() << OutputConstraint;
2464       }
2465 
2466       // Update largest vector width for any vector types.
2467       if (auto *VT = dyn_cast<llvm::VectorType>(ResultRegTypes.back()))
2468         LargestVectorWidth =
2469             std::max((uint64_t)LargestVectorWidth,
2470                      VT->getPrimitiveSizeInBits().getKnownMinSize());
2471     } else {
2472       Address DestAddr = Dest.getAddress(*this);
2473       // Matrix types in memory are represented by arrays, but accessed through
2474       // vector pointers, with the alignment specified on the access operation.
2475       // For inline assembly, update pointer arguments to use vector pointers.
2476       // Otherwise there will be a mis-match if the matrix is also an
2477       // input-argument which is represented as vector.
2478       if (isa<MatrixType>(OutExpr->getType().getCanonicalType()))
2479         DestAddr = Builder.CreateElementBitCast(
2480             DestAddr, ConvertType(OutExpr->getType()));
2481 
2482       ArgTypes.push_back(DestAddr.getType());
2483       ArgElemTypes.push_back(DestAddr.getElementType());
2484       Args.push_back(DestAddr.getPointer());
2485       Constraints += "=*";
2486       Constraints += OutputConstraint;
2487       ReadOnly = ReadNone = false;
2488     }
2489 
2490     if (Info.isReadWrite()) {
2491       InOutConstraints += ',';
2492 
2493       const Expr *InputExpr = S.getOutputExpr(i);
2494       llvm::Value *Arg;
2495       llvm::Type *ArgElemType;
2496       std::tie(Arg, ArgElemType) = EmitAsmInputLValue(
2497           Info, Dest, InputExpr->getType(), InOutConstraints,
2498           InputExpr->getExprLoc());
2499 
2500       if (llvm::Type* AdjTy =
2501           getTargetHooks().adjustInlineAsmType(*this, OutputConstraint,
2502                                                Arg->getType()))
2503         Arg = Builder.CreateBitCast(Arg, AdjTy);
2504 
2505       // Update largest vector width for any vector types.
2506       if (auto *VT = dyn_cast<llvm::VectorType>(Arg->getType()))
2507         LargestVectorWidth =
2508             std::max((uint64_t)LargestVectorWidth,
2509                      VT->getPrimitiveSizeInBits().getKnownMinSize());
2510       // Only tie earlyclobber physregs.
2511       if (Info.allowsRegister() && (GCCReg.empty() || Info.earlyClobber()))
2512         InOutConstraints += llvm::utostr(i);
2513       else
2514         InOutConstraints += OutputConstraint;
2515 
2516       InOutArgTypes.push_back(Arg->getType());
2517       InOutArgElemTypes.push_back(ArgElemType);
2518       InOutArgs.push_back(Arg);
2519     }
2520   }
2521 
2522   // If this is a Microsoft-style asm blob, store the return registers (EAX:EDX)
2523   // to the return value slot. Only do this when returning in registers.
2524   if (isa<MSAsmStmt>(&S)) {
2525     const ABIArgInfo &RetAI = CurFnInfo->getReturnInfo();
2526     if (RetAI.isDirect() || RetAI.isExtend()) {
2527       // Make a fake lvalue for the return value slot.
2528       LValue ReturnSlot = MakeAddrLValueWithoutTBAA(ReturnValue, FnRetTy);
2529       CGM.getTargetCodeGenInfo().addReturnRegisterOutputs(
2530           *this, ReturnSlot, Constraints, ResultRegTypes, ResultTruncRegTypes,
2531           ResultRegDests, AsmString, S.getNumOutputs());
2532       SawAsmBlock = true;
2533     }
2534   }
2535 
2536   for (unsigned i = 0, e = S.getNumInputs(); i != e; i++) {
2537     const Expr *InputExpr = S.getInputExpr(i);
2538 
2539     TargetInfo::ConstraintInfo &Info = InputConstraintInfos[i];
2540 
2541     if (Info.allowsMemory())
2542       ReadNone = false;
2543 
2544     if (!Constraints.empty())
2545       Constraints += ',';
2546 
2547     // Simplify the input constraint.
2548     std::string InputConstraint(S.getInputConstraint(i));
2549     InputConstraint = SimplifyConstraint(InputConstraint.c_str(), getTarget(),
2550                                          &OutputConstraintInfos);
2551 
2552     InputConstraint = AddVariableConstraints(
2553         InputConstraint, *InputExpr->IgnoreParenNoopCasts(getContext()),
2554         getTarget(), CGM, S, false /* No EarlyClobber */);
2555 
2556     std::string ReplaceConstraint (InputConstraint);
2557     llvm::Value *Arg;
2558     llvm::Type *ArgElemType;
2559     std::tie(Arg, ArgElemType) = EmitAsmInput(Info, InputExpr, Constraints);
2560 
2561     // If this input argument is tied to a larger output result, extend the
2562     // input to be the same size as the output.  The LLVM backend wants to see
2563     // the input and output of a matching constraint be the same size.  Note
2564     // that GCC does not define what the top bits are here.  We use zext because
2565     // that is usually cheaper, but LLVM IR should really get an anyext someday.
2566     if (Info.hasTiedOperand()) {
2567       unsigned Output = Info.getTiedOperand();
2568       QualType OutputType = S.getOutputExpr(Output)->getType();
2569       QualType InputTy = InputExpr->getType();
2570 
2571       if (getContext().getTypeSize(OutputType) >
2572           getContext().getTypeSize(InputTy)) {
2573         // Use ptrtoint as appropriate so that we can do our extension.
2574         if (isa<llvm::PointerType>(Arg->getType()))
2575           Arg = Builder.CreatePtrToInt(Arg, IntPtrTy);
2576         llvm::Type *OutputTy = ConvertType(OutputType);
2577         if (isa<llvm::IntegerType>(OutputTy))
2578           Arg = Builder.CreateZExt(Arg, OutputTy);
2579         else if (isa<llvm::PointerType>(OutputTy))
2580           Arg = Builder.CreateZExt(Arg, IntPtrTy);
2581         else if (OutputTy->isFloatingPointTy())
2582           Arg = Builder.CreateFPExt(Arg, OutputTy);
2583       }
2584       // Deal with the tied operands' constraint code in adjustInlineAsmType.
2585       ReplaceConstraint = OutputConstraints[Output];
2586     }
2587     if (llvm::Type* AdjTy =
2588           getTargetHooks().adjustInlineAsmType(*this, ReplaceConstraint,
2589                                                    Arg->getType()))
2590       Arg = Builder.CreateBitCast(Arg, AdjTy);
2591     else
2592       CGM.getDiags().Report(S.getAsmLoc(), diag::err_asm_invalid_type_in_input)
2593           << InputExpr->getType() << InputConstraint;
2594 
2595     // Update largest vector width for any vector types.
2596     if (auto *VT = dyn_cast<llvm::VectorType>(Arg->getType()))
2597       LargestVectorWidth =
2598           std::max((uint64_t)LargestVectorWidth,
2599                    VT->getPrimitiveSizeInBits().getKnownMinSize());
2600 
2601     ArgTypes.push_back(Arg->getType());
2602     ArgElemTypes.push_back(ArgElemType);
2603     Args.push_back(Arg);
2604     Constraints += InputConstraint;
2605   }
2606 
2607   // Append the "input" part of inout constraints.
2608   for (unsigned i = 0, e = InOutArgs.size(); i != e; i++) {
2609     ArgTypes.push_back(InOutArgTypes[i]);
2610     ArgElemTypes.push_back(InOutArgElemTypes[i]);
2611     Args.push_back(InOutArgs[i]);
2612   }
2613   Constraints += InOutConstraints;
2614 
2615   // Labels
2616   SmallVector<llvm::BasicBlock *, 16> Transfer;
2617   llvm::BasicBlock *Fallthrough = nullptr;
2618   bool IsGCCAsmGoto = false;
2619   if (const auto *GS =  dyn_cast<GCCAsmStmt>(&S)) {
2620     IsGCCAsmGoto = GS->isAsmGoto();
2621     if (IsGCCAsmGoto) {
2622       for (const auto *E : GS->labels()) {
2623         JumpDest Dest = getJumpDestForLabel(E->getLabel());
2624         Transfer.push_back(Dest.getBlock());
2625         if (!Constraints.empty())
2626           Constraints += ',';
2627         Constraints += "!i";
2628       }
2629       Fallthrough = createBasicBlock("asm.fallthrough");
2630     }
2631   }
2632 
2633   bool HasUnwindClobber = false;
2634 
2635   // Clobbers
2636   for (unsigned i = 0, e = S.getNumClobbers(); i != e; i++) {
2637     StringRef Clobber = S.getClobber(i);
2638 
2639     if (Clobber == "memory")
2640       ReadOnly = ReadNone = false;
2641     else if (Clobber == "unwind") {
2642       HasUnwindClobber = true;
2643       continue;
2644     } else if (Clobber != "cc") {
2645       Clobber = getTarget().getNormalizedGCCRegisterName(Clobber);
2646       if (CGM.getCodeGenOpts().StackClashProtector &&
2647           getTarget().isSPRegName(Clobber)) {
2648         CGM.getDiags().Report(S.getAsmLoc(),
2649                               diag::warn_stack_clash_protection_inline_asm);
2650       }
2651     }
2652 
2653     if (isa<MSAsmStmt>(&S)) {
2654       if (Clobber == "eax" || Clobber == "edx") {
2655         if (Constraints.find("=&A") != std::string::npos)
2656           continue;
2657         std::string::size_type position1 =
2658             Constraints.find("={" + Clobber.str() + "}");
2659         if (position1 != std::string::npos) {
2660           Constraints.insert(position1 + 1, "&");
2661           continue;
2662         }
2663         std::string::size_type position2 = Constraints.find("=A");
2664         if (position2 != std::string::npos) {
2665           Constraints.insert(position2 + 1, "&");
2666           continue;
2667         }
2668       }
2669     }
2670     if (!Constraints.empty())
2671       Constraints += ',';
2672 
2673     Constraints += "~{";
2674     Constraints += Clobber;
2675     Constraints += '}';
2676   }
2677 
2678   assert(!(HasUnwindClobber && IsGCCAsmGoto) &&
2679          "unwind clobber can't be used with asm goto");
2680 
2681   // Add machine specific clobbers
2682   std::string MachineClobbers = getTarget().getClobbers();
2683   if (!MachineClobbers.empty()) {
2684     if (!Constraints.empty())
2685       Constraints += ',';
2686     Constraints += MachineClobbers;
2687   }
2688 
2689   llvm::Type *ResultType;
2690   if (ResultRegTypes.empty())
2691     ResultType = VoidTy;
2692   else if (ResultRegTypes.size() == 1)
2693     ResultType = ResultRegTypes[0];
2694   else
2695     ResultType = llvm::StructType::get(getLLVMContext(), ResultRegTypes);
2696 
2697   llvm::FunctionType *FTy =
2698     llvm::FunctionType::get(ResultType, ArgTypes, false);
2699 
2700   bool HasSideEffect = S.isVolatile() || S.getNumOutputs() == 0;
2701 
2702   llvm::InlineAsm::AsmDialect GnuAsmDialect =
2703       CGM.getCodeGenOpts().getInlineAsmDialect() == CodeGenOptions::IAD_ATT
2704           ? llvm::InlineAsm::AD_ATT
2705           : llvm::InlineAsm::AD_Intel;
2706   llvm::InlineAsm::AsmDialect AsmDialect = isa<MSAsmStmt>(&S) ?
2707     llvm::InlineAsm::AD_Intel : GnuAsmDialect;
2708 
2709   llvm::InlineAsm *IA = llvm::InlineAsm::get(
2710       FTy, AsmString, Constraints, HasSideEffect,
2711       /* IsAlignStack */ false, AsmDialect, HasUnwindClobber);
2712   std::vector<llvm::Value*> RegResults;
2713   if (IsGCCAsmGoto) {
2714     llvm::CallBrInst *Result =
2715         Builder.CreateCallBr(IA, Fallthrough, Transfer, Args);
2716     EmitBlock(Fallthrough);
2717     UpdateAsmCallInst(cast<llvm::CallBase>(*Result), HasSideEffect, false,
2718                       ReadOnly, ReadNone, InNoMergeAttributedStmt, S,
2719                       ResultRegTypes, ArgElemTypes, *this, RegResults);
2720   } else if (HasUnwindClobber) {
2721     llvm::CallBase *Result = EmitCallOrInvoke(IA, Args, "");
2722     UpdateAsmCallInst(*Result, HasSideEffect, true, ReadOnly, ReadNone,
2723                       InNoMergeAttributedStmt, S, ResultRegTypes, ArgElemTypes,
2724                       *this, RegResults);
2725   } else {
2726     llvm::CallInst *Result =
2727         Builder.CreateCall(IA, Args, getBundlesForFunclet(IA));
2728     UpdateAsmCallInst(cast<llvm::CallBase>(*Result), HasSideEffect, false,
2729                       ReadOnly, ReadNone, InNoMergeAttributedStmt, S,
2730                       ResultRegTypes, ArgElemTypes, *this, RegResults);
2731   }
2732 
2733   assert(RegResults.size() == ResultRegTypes.size());
2734   assert(RegResults.size() == ResultTruncRegTypes.size());
2735   assert(RegResults.size() == ResultRegDests.size());
2736   // ResultRegDests can be also populated by addReturnRegisterOutputs() above,
2737   // in which case its size may grow.
2738   assert(ResultTypeRequiresCast.size() <= ResultRegDests.size());
2739   assert(ResultRegIsFlagReg.size() <= ResultRegDests.size());
2740   for (unsigned i = 0, e = RegResults.size(); i != e; ++i) {
2741     llvm::Value *Tmp = RegResults[i];
2742     llvm::Type *TruncTy = ResultTruncRegTypes[i];
2743 
2744     if ((i < ResultRegIsFlagReg.size()) && ResultRegIsFlagReg[i]) {
2745       // Target must guarantee the Value `Tmp` here is lowered to a boolean
2746       // value.
2747       llvm::Constant *Two = llvm::ConstantInt::get(Tmp->getType(), 2);
2748       llvm::Value *IsBooleanValue =
2749           Builder.CreateCmp(llvm::CmpInst::ICMP_ULT, Tmp, Two);
2750       llvm::Function *FnAssume = CGM.getIntrinsic(llvm::Intrinsic::assume);
2751       Builder.CreateCall(FnAssume, IsBooleanValue);
2752     }
2753 
2754     // If the result type of the LLVM IR asm doesn't match the result type of
2755     // the expression, do the conversion.
2756     if (ResultRegTypes[i] != ResultTruncRegTypes[i]) {
2757 
2758       // Truncate the integer result to the right size, note that TruncTy can be
2759       // a pointer.
2760       if (TruncTy->isFloatingPointTy())
2761         Tmp = Builder.CreateFPTrunc(Tmp, TruncTy);
2762       else if (TruncTy->isPointerTy() && Tmp->getType()->isIntegerTy()) {
2763         uint64_t ResSize = CGM.getDataLayout().getTypeSizeInBits(TruncTy);
2764         Tmp = Builder.CreateTrunc(Tmp,
2765                    llvm::IntegerType::get(getLLVMContext(), (unsigned)ResSize));
2766         Tmp = Builder.CreateIntToPtr(Tmp, TruncTy);
2767       } else if (Tmp->getType()->isPointerTy() && TruncTy->isIntegerTy()) {
2768         uint64_t TmpSize =CGM.getDataLayout().getTypeSizeInBits(Tmp->getType());
2769         Tmp = Builder.CreatePtrToInt(Tmp,
2770                    llvm::IntegerType::get(getLLVMContext(), (unsigned)TmpSize));
2771         Tmp = Builder.CreateTrunc(Tmp, TruncTy);
2772       } else if (TruncTy->isIntegerTy()) {
2773         Tmp = Builder.CreateZExtOrTrunc(Tmp, TruncTy);
2774       } else if (TruncTy->isVectorTy()) {
2775         Tmp = Builder.CreateBitCast(Tmp, TruncTy);
2776       }
2777     }
2778 
2779     LValue Dest = ResultRegDests[i];
2780     // ResultTypeRequiresCast elements correspond to the first
2781     // ResultTypeRequiresCast.size() elements of RegResults.
2782     if ((i < ResultTypeRequiresCast.size()) && ResultTypeRequiresCast[i]) {
2783       unsigned Size = getContext().getTypeSize(ResultRegQualTys[i]);
2784       Address A = Builder.CreateElementBitCast(Dest.getAddress(*this),
2785                                                ResultRegTypes[i]);
2786       if (getTargetHooks().isScalarizableAsmOperand(*this, TruncTy)) {
2787         Builder.CreateStore(Tmp, A);
2788         continue;
2789       }
2790 
2791       QualType Ty = getContext().getIntTypeForBitwidth(Size, /*Signed*/ false);
2792       if (Ty.isNull()) {
2793         const Expr *OutExpr = S.getOutputExpr(i);
2794         CGM.getDiags().Report(OutExpr->getExprLoc(),
2795                               diag::err_store_value_to_reg);
2796         return;
2797       }
2798       Dest = MakeAddrLValue(A, Ty);
2799     }
2800     EmitStoreThroughLValue(RValue::get(Tmp), Dest);
2801   }
2802 }
2803 
2804 LValue CodeGenFunction::InitCapturedStruct(const CapturedStmt &S) {
2805   const RecordDecl *RD = S.getCapturedRecordDecl();
2806   QualType RecordTy = getContext().getRecordType(RD);
2807 
2808   // Initialize the captured struct.
2809   LValue SlotLV =
2810     MakeAddrLValue(CreateMemTemp(RecordTy, "agg.captured"), RecordTy);
2811 
2812   RecordDecl::field_iterator CurField = RD->field_begin();
2813   for (CapturedStmt::const_capture_init_iterator I = S.capture_init_begin(),
2814                                                  E = S.capture_init_end();
2815        I != E; ++I, ++CurField) {
2816     LValue LV = EmitLValueForFieldInitialization(SlotLV, *CurField);
2817     if (CurField->hasCapturedVLAType()) {
2818       EmitLambdaVLACapture(CurField->getCapturedVLAType(), LV);
2819     } else {
2820       EmitInitializerForField(*CurField, LV, *I);
2821     }
2822   }
2823 
2824   return SlotLV;
2825 }
2826 
2827 /// Generate an outlined function for the body of a CapturedStmt, store any
2828 /// captured variables into the captured struct, and call the outlined function.
2829 llvm::Function *
2830 CodeGenFunction::EmitCapturedStmt(const CapturedStmt &S, CapturedRegionKind K) {
2831   LValue CapStruct = InitCapturedStruct(S);
2832 
2833   // Emit the CapturedDecl
2834   CodeGenFunction CGF(CGM, true);
2835   CGCapturedStmtRAII CapInfoRAII(CGF, new CGCapturedStmtInfo(S, K));
2836   llvm::Function *F = CGF.GenerateCapturedStmtFunction(S);
2837   delete CGF.CapturedStmtInfo;
2838 
2839   // Emit call to the helper function.
2840   EmitCallOrInvoke(F, CapStruct.getPointer(*this));
2841 
2842   return F;
2843 }
2844 
2845 Address CodeGenFunction::GenerateCapturedStmtArgument(const CapturedStmt &S) {
2846   LValue CapStruct = InitCapturedStruct(S);
2847   return CapStruct.getAddress(*this);
2848 }
2849 
2850 /// Creates the outlined function for a CapturedStmt.
2851 llvm::Function *
2852 CodeGenFunction::GenerateCapturedStmtFunction(const CapturedStmt &S) {
2853   assert(CapturedStmtInfo &&
2854     "CapturedStmtInfo should be set when generating the captured function");
2855   const CapturedDecl *CD = S.getCapturedDecl();
2856   const RecordDecl *RD = S.getCapturedRecordDecl();
2857   SourceLocation Loc = S.getBeginLoc();
2858   assert(CD->hasBody() && "missing CapturedDecl body");
2859 
2860   // Build the argument list.
2861   ASTContext &Ctx = CGM.getContext();
2862   FunctionArgList Args;
2863   Args.append(CD->param_begin(), CD->param_end());
2864 
2865   // Create the function declaration.
2866   const CGFunctionInfo &FuncInfo =
2867     CGM.getTypes().arrangeBuiltinFunctionDeclaration(Ctx.VoidTy, Args);
2868   llvm::FunctionType *FuncLLVMTy = CGM.getTypes().GetFunctionType(FuncInfo);
2869 
2870   llvm::Function *F =
2871     llvm::Function::Create(FuncLLVMTy, llvm::GlobalValue::InternalLinkage,
2872                            CapturedStmtInfo->getHelperName(), &CGM.getModule());
2873   CGM.SetInternalFunctionAttributes(CD, F, FuncInfo);
2874   if (CD->isNothrow())
2875     F->addFnAttr(llvm::Attribute::NoUnwind);
2876 
2877   // Generate the function.
2878   StartFunction(CD, Ctx.VoidTy, F, FuncInfo, Args, CD->getLocation(),
2879                 CD->getBody()->getBeginLoc());
2880   // Set the context parameter in CapturedStmtInfo.
2881   Address DeclPtr = GetAddrOfLocalVar(CD->getContextParam());
2882   CapturedStmtInfo->setContextValue(Builder.CreateLoad(DeclPtr));
2883 
2884   // Initialize variable-length arrays.
2885   LValue Base = MakeNaturalAlignAddrLValue(CapturedStmtInfo->getContextValue(),
2886                                            Ctx.getTagDeclType(RD));
2887   for (auto *FD : RD->fields()) {
2888     if (FD->hasCapturedVLAType()) {
2889       auto *ExprArg =
2890           EmitLoadOfLValue(EmitLValueForField(Base, FD), S.getBeginLoc())
2891               .getScalarVal();
2892       auto VAT = FD->getCapturedVLAType();
2893       VLASizeMap[VAT->getSizeExpr()] = ExprArg;
2894     }
2895   }
2896 
2897   // If 'this' is captured, load it into CXXThisValue.
2898   if (CapturedStmtInfo->isCXXThisExprCaptured()) {
2899     FieldDecl *FD = CapturedStmtInfo->getThisFieldDecl();
2900     LValue ThisLValue = EmitLValueForField(Base, FD);
2901     CXXThisValue = EmitLoadOfLValue(ThisLValue, Loc).getScalarVal();
2902   }
2903 
2904   PGO.assignRegionCounters(GlobalDecl(CD), F);
2905   CapturedStmtInfo->EmitBody(*this, CD->getBody());
2906   FinishFunction(CD->getBodyRBrace());
2907 
2908   return F;
2909 }
2910