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/ArrayRef.h"
28 #include "llvm/ADT/DenseMap.h"
29 #include "llvm/ADT/SmallSet.h"
30 #include "llvm/ADT/StringExtras.h"
31 #include "llvm/IR/Assumptions.h"
32 #include "llvm/IR/DataLayout.h"
33 #include "llvm/IR/InlineAsm.h"
34 #include "llvm/IR/Intrinsics.h"
35 #include "llvm/IR/MDBuilder.h"
36 #include "llvm/Support/SaveAndRestore.h"
37 #include <optional>
38 
39 using namespace clang;
40 using namespace CodeGen;
41 
42 //===----------------------------------------------------------------------===//
43 //                              Statement Emission
44 //===----------------------------------------------------------------------===//
45 
46 void CodeGenFunction::EmitStopPoint(const Stmt *S) {
47   if (CGDebugInfo *DI = getDebugInfo()) {
48     SourceLocation Loc;
49     Loc = S->getBeginLoc();
50     DI->EmitLocation(Builder, Loc);
51 
52     LastStopPoint = Loc;
53   }
54 }
55 
56 void CodeGenFunction::EmitStmt(const Stmt *S, ArrayRef<const Attr *> Attrs) {
57   assert(S && "Null statement?");
58   PGO.setCurrentStmt(S);
59 
60   // These statements have their own debug info handling.
61   if (EmitSimpleStmt(S, Attrs))
62     return;
63 
64   // Check if we are generating unreachable code.
65   if (!HaveInsertPoint()) {
66     // If so, and the statement doesn't contain a label, then we do not need to
67     // generate actual code. This is safe because (1) the current point is
68     // unreachable, so we don't need to execute the code, and (2) we've already
69     // handled the statements which update internal data structures (like the
70     // local variable map) which could be used by subsequent statements.
71     if (!ContainsLabel(S)) {
72       // Verify that any decl statements were handled as simple, they may be in
73       // scope of subsequent reachable statements.
74       assert(!isa<DeclStmt>(*S) && "Unexpected DeclStmt!");
75       return;
76     }
77 
78     // Otherwise, make a new block to hold the code.
79     EnsureInsertPoint();
80   }
81 
82   // Generate a stoppoint if we are emitting debug info.
83   EmitStopPoint(S);
84 
85   // Ignore all OpenMP directives except for simd if OpenMP with Simd is
86   // enabled.
87   if (getLangOpts().OpenMP && getLangOpts().OpenMPSimd) {
88     if (const auto *D = dyn_cast<OMPExecutableDirective>(S)) {
89       EmitSimpleOMPExecutableDirective(*D);
90       return;
91     }
92   }
93 
94   switch (S->getStmtClass()) {
95   case Stmt::NoStmtClass:
96   case Stmt::CXXCatchStmtClass:
97   case Stmt::SEHExceptStmtClass:
98   case Stmt::SEHFinallyStmtClass:
99   case Stmt::MSDependentExistsStmtClass:
100     llvm_unreachable("invalid statement class to emit generically");
101   case Stmt::NullStmtClass:
102   case Stmt::CompoundStmtClass:
103   case Stmt::DeclStmtClass:
104   case Stmt::LabelStmtClass:
105   case Stmt::AttributedStmtClass:
106   case Stmt::GotoStmtClass:
107   case Stmt::BreakStmtClass:
108   case Stmt::ContinueStmtClass:
109   case Stmt::DefaultStmtClass:
110   case Stmt::CaseStmtClass:
111   case Stmt::SEHLeaveStmtClass:
112     llvm_unreachable("should have emitted these statements as simple");
113 
114 #define STMT(Type, Base)
115 #define ABSTRACT_STMT(Op)
116 #define EXPR(Type, Base) \
117   case Stmt::Type##Class:
118 #include "clang/AST/StmtNodes.inc"
119   {
120     // Remember the block we came in on.
121     llvm::BasicBlock *incoming = Builder.GetInsertBlock();
122     assert(incoming && "expression emission must have an insertion point");
123 
124     EmitIgnoredExpr(cast<Expr>(S));
125 
126     llvm::BasicBlock *outgoing = Builder.GetInsertBlock();
127     assert(outgoing && "expression emission cleared block!");
128 
129     // The expression emitters assume (reasonably!) that the insertion
130     // point is always set.  To maintain that, the call-emission code
131     // for noreturn functions has to enter a new block with no
132     // predecessors.  We want to kill that block and mark the current
133     // insertion point unreachable in the common case of a call like
134     // "exit();".  Since expression emission doesn't otherwise create
135     // blocks with no predecessors, we can just test for that.
136     // However, we must be careful not to do this to our incoming
137     // block, because *statement* emission does sometimes create
138     // reachable blocks which will have no predecessors until later in
139     // the function.  This occurs with, e.g., labels that are not
140     // reachable by fallthrough.
141     if (incoming != outgoing && outgoing->use_empty()) {
142       outgoing->eraseFromParent();
143       Builder.ClearInsertionPoint();
144     }
145     break;
146   }
147 
148   case Stmt::IndirectGotoStmtClass:
149     EmitIndirectGotoStmt(cast<IndirectGotoStmt>(*S)); break;
150 
151   case Stmt::IfStmtClass:      EmitIfStmt(cast<IfStmt>(*S));              break;
152   case Stmt::WhileStmtClass:   EmitWhileStmt(cast<WhileStmt>(*S), Attrs); break;
153   case Stmt::DoStmtClass:      EmitDoStmt(cast<DoStmt>(*S), Attrs);       break;
154   case Stmt::ForStmtClass:     EmitForStmt(cast<ForStmt>(*S), Attrs);     break;
155 
156   case Stmt::ReturnStmtClass:  EmitReturnStmt(cast<ReturnStmt>(*S));      break;
157 
158   case Stmt::SwitchStmtClass:  EmitSwitchStmt(cast<SwitchStmt>(*S));      break;
159   case Stmt::GCCAsmStmtClass:  // Intentional fall-through.
160   case Stmt::MSAsmStmtClass:   EmitAsmStmt(cast<AsmStmt>(*S));            break;
161   case Stmt::CoroutineBodyStmtClass:
162     EmitCoroutineBody(cast<CoroutineBodyStmt>(*S));
163     break;
164   case Stmt::CoreturnStmtClass:
165     EmitCoreturnStmt(cast<CoreturnStmt>(*S));
166     break;
167   case Stmt::CapturedStmtClass: {
168     const CapturedStmt *CS = cast<CapturedStmt>(S);
169     EmitCapturedStmt(*CS, CS->getCapturedRegionKind());
170     }
171     break;
172   case Stmt::ObjCAtTryStmtClass:
173     EmitObjCAtTryStmt(cast<ObjCAtTryStmt>(*S));
174     break;
175   case Stmt::ObjCAtCatchStmtClass:
176     llvm_unreachable(
177                     "@catch statements should be handled by EmitObjCAtTryStmt");
178   case Stmt::ObjCAtFinallyStmtClass:
179     llvm_unreachable(
180                   "@finally statements should be handled by EmitObjCAtTryStmt");
181   case Stmt::ObjCAtThrowStmtClass:
182     EmitObjCAtThrowStmt(cast<ObjCAtThrowStmt>(*S));
183     break;
184   case Stmt::ObjCAtSynchronizedStmtClass:
185     EmitObjCAtSynchronizedStmt(cast<ObjCAtSynchronizedStmt>(*S));
186     break;
187   case Stmt::ObjCForCollectionStmtClass:
188     EmitObjCForCollectionStmt(cast<ObjCForCollectionStmt>(*S));
189     break;
190   case Stmt::ObjCAutoreleasePoolStmtClass:
191     EmitObjCAutoreleasePoolStmt(cast<ObjCAutoreleasePoolStmt>(*S));
192     break;
193 
194   case Stmt::CXXTryStmtClass:
195     EmitCXXTryStmt(cast<CXXTryStmt>(*S));
196     break;
197   case Stmt::CXXForRangeStmtClass:
198     EmitCXXForRangeStmt(cast<CXXForRangeStmt>(*S), Attrs);
199     break;
200   case Stmt::SEHTryStmtClass:
201     EmitSEHTryStmt(cast<SEHTryStmt>(*S));
202     break;
203   case Stmt::OMPMetaDirectiveClass:
204     EmitOMPMetaDirective(cast<OMPMetaDirective>(*S));
205     break;
206   case Stmt::OMPCanonicalLoopClass:
207     EmitOMPCanonicalLoop(cast<OMPCanonicalLoop>(S));
208     break;
209   case Stmt::OMPParallelDirectiveClass:
210     EmitOMPParallelDirective(cast<OMPParallelDirective>(*S));
211     break;
212   case Stmt::OMPSimdDirectiveClass:
213     EmitOMPSimdDirective(cast<OMPSimdDirective>(*S));
214     break;
215   case Stmt::OMPTileDirectiveClass:
216     EmitOMPTileDirective(cast<OMPTileDirective>(*S));
217     break;
218   case Stmt::OMPUnrollDirectiveClass:
219     EmitOMPUnrollDirective(cast<OMPUnrollDirective>(*S));
220     break;
221   case Stmt::OMPForDirectiveClass:
222     EmitOMPForDirective(cast<OMPForDirective>(*S));
223     break;
224   case Stmt::OMPForSimdDirectiveClass:
225     EmitOMPForSimdDirective(cast<OMPForSimdDirective>(*S));
226     break;
227   case Stmt::OMPSectionsDirectiveClass:
228     EmitOMPSectionsDirective(cast<OMPSectionsDirective>(*S));
229     break;
230   case Stmt::OMPSectionDirectiveClass:
231     EmitOMPSectionDirective(cast<OMPSectionDirective>(*S));
232     break;
233   case Stmt::OMPSingleDirectiveClass:
234     EmitOMPSingleDirective(cast<OMPSingleDirective>(*S));
235     break;
236   case Stmt::OMPMasterDirectiveClass:
237     EmitOMPMasterDirective(cast<OMPMasterDirective>(*S));
238     break;
239   case Stmt::OMPCriticalDirectiveClass:
240     EmitOMPCriticalDirective(cast<OMPCriticalDirective>(*S));
241     break;
242   case Stmt::OMPParallelForDirectiveClass:
243     EmitOMPParallelForDirective(cast<OMPParallelForDirective>(*S));
244     break;
245   case Stmt::OMPParallelForSimdDirectiveClass:
246     EmitOMPParallelForSimdDirective(cast<OMPParallelForSimdDirective>(*S));
247     break;
248   case Stmt::OMPParallelMasterDirectiveClass:
249     EmitOMPParallelMasterDirective(cast<OMPParallelMasterDirective>(*S));
250     break;
251   case Stmt::OMPParallelSectionsDirectiveClass:
252     EmitOMPParallelSectionsDirective(cast<OMPParallelSectionsDirective>(*S));
253     break;
254   case Stmt::OMPTaskDirectiveClass:
255     EmitOMPTaskDirective(cast<OMPTaskDirective>(*S));
256     break;
257   case Stmt::OMPTaskyieldDirectiveClass:
258     EmitOMPTaskyieldDirective(cast<OMPTaskyieldDirective>(*S));
259     break;
260   case Stmt::OMPErrorDirectiveClass:
261     EmitOMPErrorDirective(cast<OMPErrorDirective>(*S));
262     break;
263   case Stmt::OMPBarrierDirectiveClass:
264     EmitOMPBarrierDirective(cast<OMPBarrierDirective>(*S));
265     break;
266   case Stmt::OMPTaskwaitDirectiveClass:
267     EmitOMPTaskwaitDirective(cast<OMPTaskwaitDirective>(*S));
268     break;
269   case Stmt::OMPTaskgroupDirectiveClass:
270     EmitOMPTaskgroupDirective(cast<OMPTaskgroupDirective>(*S));
271     break;
272   case Stmt::OMPFlushDirectiveClass:
273     EmitOMPFlushDirective(cast<OMPFlushDirective>(*S));
274     break;
275   case Stmt::OMPDepobjDirectiveClass:
276     EmitOMPDepobjDirective(cast<OMPDepobjDirective>(*S));
277     break;
278   case Stmt::OMPScanDirectiveClass:
279     EmitOMPScanDirective(cast<OMPScanDirective>(*S));
280     break;
281   case Stmt::OMPOrderedDirectiveClass:
282     EmitOMPOrderedDirective(cast<OMPOrderedDirective>(*S));
283     break;
284   case Stmt::OMPAtomicDirectiveClass:
285     EmitOMPAtomicDirective(cast<OMPAtomicDirective>(*S));
286     break;
287   case Stmt::OMPTargetDirectiveClass:
288     EmitOMPTargetDirective(cast<OMPTargetDirective>(*S));
289     break;
290   case Stmt::OMPTeamsDirectiveClass:
291     EmitOMPTeamsDirective(cast<OMPTeamsDirective>(*S));
292     break;
293   case Stmt::OMPCancellationPointDirectiveClass:
294     EmitOMPCancellationPointDirective(cast<OMPCancellationPointDirective>(*S));
295     break;
296   case Stmt::OMPCancelDirectiveClass:
297     EmitOMPCancelDirective(cast<OMPCancelDirective>(*S));
298     break;
299   case Stmt::OMPTargetDataDirectiveClass:
300     EmitOMPTargetDataDirective(cast<OMPTargetDataDirective>(*S));
301     break;
302   case Stmt::OMPTargetEnterDataDirectiveClass:
303     EmitOMPTargetEnterDataDirective(cast<OMPTargetEnterDataDirective>(*S));
304     break;
305   case Stmt::OMPTargetExitDataDirectiveClass:
306     EmitOMPTargetExitDataDirective(cast<OMPTargetExitDataDirective>(*S));
307     break;
308   case Stmt::OMPTargetParallelDirectiveClass:
309     EmitOMPTargetParallelDirective(cast<OMPTargetParallelDirective>(*S));
310     break;
311   case Stmt::OMPTargetParallelForDirectiveClass:
312     EmitOMPTargetParallelForDirective(cast<OMPTargetParallelForDirective>(*S));
313     break;
314   case Stmt::OMPTaskLoopDirectiveClass:
315     EmitOMPTaskLoopDirective(cast<OMPTaskLoopDirective>(*S));
316     break;
317   case Stmt::OMPTaskLoopSimdDirectiveClass:
318     EmitOMPTaskLoopSimdDirective(cast<OMPTaskLoopSimdDirective>(*S));
319     break;
320   case Stmt::OMPMasterTaskLoopDirectiveClass:
321     EmitOMPMasterTaskLoopDirective(cast<OMPMasterTaskLoopDirective>(*S));
322     break;
323   case Stmt::OMPMaskedTaskLoopDirectiveClass:
324     llvm_unreachable("masked taskloop directive not supported yet.");
325     break;
326   case Stmt::OMPMasterTaskLoopSimdDirectiveClass:
327     EmitOMPMasterTaskLoopSimdDirective(
328         cast<OMPMasterTaskLoopSimdDirective>(*S));
329     break;
330   case Stmt::OMPMaskedTaskLoopSimdDirectiveClass:
331     llvm_unreachable("masked taskloop simd directive not supported yet.");
332     break;
333   case Stmt::OMPParallelMasterTaskLoopDirectiveClass:
334     EmitOMPParallelMasterTaskLoopDirective(
335         cast<OMPParallelMasterTaskLoopDirective>(*S));
336     break;
337   case Stmt::OMPParallelMaskedTaskLoopDirectiveClass:
338     llvm_unreachable("parallel masked taskloop directive not supported yet.");
339     break;
340   case Stmt::OMPParallelMasterTaskLoopSimdDirectiveClass:
341     EmitOMPParallelMasterTaskLoopSimdDirective(
342         cast<OMPParallelMasterTaskLoopSimdDirective>(*S));
343     break;
344   case Stmt::OMPParallelMaskedTaskLoopSimdDirectiveClass:
345     llvm_unreachable(
346         "parallel masked taskloop simd directive not supported yet.");
347     break;
348   case Stmt::OMPDistributeDirectiveClass:
349     EmitOMPDistributeDirective(cast<OMPDistributeDirective>(*S));
350     break;
351   case Stmt::OMPTargetUpdateDirectiveClass:
352     EmitOMPTargetUpdateDirective(cast<OMPTargetUpdateDirective>(*S));
353     break;
354   case Stmt::OMPDistributeParallelForDirectiveClass:
355     EmitOMPDistributeParallelForDirective(
356         cast<OMPDistributeParallelForDirective>(*S));
357     break;
358   case Stmt::OMPDistributeParallelForSimdDirectiveClass:
359     EmitOMPDistributeParallelForSimdDirective(
360         cast<OMPDistributeParallelForSimdDirective>(*S));
361     break;
362   case Stmt::OMPDistributeSimdDirectiveClass:
363     EmitOMPDistributeSimdDirective(cast<OMPDistributeSimdDirective>(*S));
364     break;
365   case Stmt::OMPTargetParallelForSimdDirectiveClass:
366     EmitOMPTargetParallelForSimdDirective(
367         cast<OMPTargetParallelForSimdDirective>(*S));
368     break;
369   case Stmt::OMPTargetSimdDirectiveClass:
370     EmitOMPTargetSimdDirective(cast<OMPTargetSimdDirective>(*S));
371     break;
372   case Stmt::OMPTeamsDistributeDirectiveClass:
373     EmitOMPTeamsDistributeDirective(cast<OMPTeamsDistributeDirective>(*S));
374     break;
375   case Stmt::OMPTeamsDistributeSimdDirectiveClass:
376     EmitOMPTeamsDistributeSimdDirective(
377         cast<OMPTeamsDistributeSimdDirective>(*S));
378     break;
379   case Stmt::OMPTeamsDistributeParallelForSimdDirectiveClass:
380     EmitOMPTeamsDistributeParallelForSimdDirective(
381         cast<OMPTeamsDistributeParallelForSimdDirective>(*S));
382     break;
383   case Stmt::OMPTeamsDistributeParallelForDirectiveClass:
384     EmitOMPTeamsDistributeParallelForDirective(
385         cast<OMPTeamsDistributeParallelForDirective>(*S));
386     break;
387   case Stmt::OMPTargetTeamsDirectiveClass:
388     EmitOMPTargetTeamsDirective(cast<OMPTargetTeamsDirective>(*S));
389     break;
390   case Stmt::OMPTargetTeamsDistributeDirectiveClass:
391     EmitOMPTargetTeamsDistributeDirective(
392         cast<OMPTargetTeamsDistributeDirective>(*S));
393     break;
394   case Stmt::OMPTargetTeamsDistributeParallelForDirectiveClass:
395     EmitOMPTargetTeamsDistributeParallelForDirective(
396         cast<OMPTargetTeamsDistributeParallelForDirective>(*S));
397     break;
398   case Stmt::OMPTargetTeamsDistributeParallelForSimdDirectiveClass:
399     EmitOMPTargetTeamsDistributeParallelForSimdDirective(
400         cast<OMPTargetTeamsDistributeParallelForSimdDirective>(*S));
401     break;
402   case Stmt::OMPTargetTeamsDistributeSimdDirectiveClass:
403     EmitOMPTargetTeamsDistributeSimdDirective(
404         cast<OMPTargetTeamsDistributeSimdDirective>(*S));
405     break;
406   case Stmt::OMPInteropDirectiveClass:
407     EmitOMPInteropDirective(cast<OMPInteropDirective>(*S));
408     break;
409   case Stmt::OMPDispatchDirectiveClass:
410     CGM.ErrorUnsupported(S, "OpenMP dispatch directive");
411     break;
412   case Stmt::OMPScopeDirectiveClass:
413     llvm_unreachable("scope not supported with FE outlining");
414   case Stmt::OMPMaskedDirectiveClass:
415     EmitOMPMaskedDirective(cast<OMPMaskedDirective>(*S));
416     break;
417   case Stmt::OMPGenericLoopDirectiveClass:
418     EmitOMPGenericLoopDirective(cast<OMPGenericLoopDirective>(*S));
419     break;
420   case Stmt::OMPTeamsGenericLoopDirectiveClass:
421     EmitOMPTeamsGenericLoopDirective(cast<OMPTeamsGenericLoopDirective>(*S));
422     break;
423   case Stmt::OMPTargetTeamsGenericLoopDirectiveClass:
424     EmitOMPTargetTeamsGenericLoopDirective(
425         cast<OMPTargetTeamsGenericLoopDirective>(*S));
426     break;
427   case Stmt::OMPParallelGenericLoopDirectiveClass:
428     EmitOMPParallelGenericLoopDirective(
429         cast<OMPParallelGenericLoopDirective>(*S));
430     break;
431   case Stmt::OMPTargetParallelGenericLoopDirectiveClass:
432     EmitOMPTargetParallelGenericLoopDirective(
433         cast<OMPTargetParallelGenericLoopDirective>(*S));
434     break;
435   case Stmt::OMPParallelMaskedDirectiveClass:
436     EmitOMPParallelMaskedDirective(cast<OMPParallelMaskedDirective>(*S));
437     break;
438   }
439 }
440 
441 bool CodeGenFunction::EmitSimpleStmt(const Stmt *S,
442                                      ArrayRef<const Attr *> Attrs) {
443   switch (S->getStmtClass()) {
444   default:
445     return false;
446   case Stmt::NullStmtClass:
447     break;
448   case Stmt::CompoundStmtClass:
449     EmitCompoundStmt(cast<CompoundStmt>(*S));
450     break;
451   case Stmt::DeclStmtClass:
452     EmitDeclStmt(cast<DeclStmt>(*S));
453     break;
454   case Stmt::LabelStmtClass:
455     EmitLabelStmt(cast<LabelStmt>(*S));
456     break;
457   case Stmt::AttributedStmtClass:
458     EmitAttributedStmt(cast<AttributedStmt>(*S));
459     break;
460   case Stmt::GotoStmtClass:
461     EmitGotoStmt(cast<GotoStmt>(*S));
462     break;
463   case Stmt::BreakStmtClass:
464     EmitBreakStmt(cast<BreakStmt>(*S));
465     break;
466   case Stmt::ContinueStmtClass:
467     EmitContinueStmt(cast<ContinueStmt>(*S));
468     break;
469   case Stmt::DefaultStmtClass:
470     EmitDefaultStmt(cast<DefaultStmt>(*S), Attrs);
471     break;
472   case Stmt::CaseStmtClass:
473     EmitCaseStmt(cast<CaseStmt>(*S), Attrs);
474     break;
475   case Stmt::SEHLeaveStmtClass:
476     EmitSEHLeaveStmt(cast<SEHLeaveStmt>(*S));
477     break;
478   }
479   return true;
480 }
481 
482 /// EmitCompoundStmt - Emit a compound statement {..} node.  If GetLast is true,
483 /// this captures the expression result of the last sub-statement and returns it
484 /// (for use by the statement expression extension).
485 Address CodeGenFunction::EmitCompoundStmt(const CompoundStmt &S, bool GetLast,
486                                           AggValueSlot AggSlot) {
487   PrettyStackTraceLoc CrashInfo(getContext().getSourceManager(),S.getLBracLoc(),
488                              "LLVM IR generation of compound statement ('{}')");
489 
490   // Keep track of the current cleanup stack depth, including debug scopes.
491   LexicalScope Scope(*this, S.getSourceRange());
492 
493   return EmitCompoundStmtWithoutScope(S, GetLast, AggSlot);
494 }
495 
496 Address
497 CodeGenFunction::EmitCompoundStmtWithoutScope(const CompoundStmt &S,
498                                               bool GetLast,
499                                               AggValueSlot AggSlot) {
500 
501   const Stmt *ExprResult = S.getStmtExprResult();
502   assert((!GetLast || (GetLast && ExprResult)) &&
503          "If GetLast is true then the CompoundStmt must have a StmtExprResult");
504 
505   Address RetAlloca = Address::invalid();
506 
507   for (auto *CurStmt : S.body()) {
508     if (GetLast && ExprResult == CurStmt) {
509       // We have to special case labels here.  They are statements, but when put
510       // at the end of a statement expression, they yield the value of their
511       // subexpression.  Handle this by walking through all labels we encounter,
512       // emitting them before we evaluate the subexpr.
513       // Similar issues arise for attributed statements.
514       while (!isa<Expr>(ExprResult)) {
515         if (const auto *LS = dyn_cast<LabelStmt>(ExprResult)) {
516           EmitLabel(LS->getDecl());
517           ExprResult = LS->getSubStmt();
518         } else if (const auto *AS = dyn_cast<AttributedStmt>(ExprResult)) {
519           // FIXME: Update this if we ever have attributes that affect the
520           // semantics of an expression.
521           ExprResult = AS->getSubStmt();
522         } else {
523           llvm_unreachable("unknown value statement");
524         }
525       }
526 
527       EnsureInsertPoint();
528 
529       const Expr *E = cast<Expr>(ExprResult);
530       QualType ExprTy = E->getType();
531       if (hasAggregateEvaluationKind(ExprTy)) {
532         EmitAggExpr(E, AggSlot);
533       } else {
534         // We can't return an RValue here because there might be cleanups at
535         // the end of the StmtExpr.  Because of that, we have to emit the result
536         // here into a temporary alloca.
537         RetAlloca = CreateMemTemp(ExprTy);
538         EmitAnyExprToMem(E, RetAlloca, Qualifiers(),
539                          /*IsInit*/ false);
540       }
541     } else {
542       EmitStmt(CurStmt);
543     }
544   }
545 
546   return RetAlloca;
547 }
548 
549 void CodeGenFunction::SimplifyForwardingBlocks(llvm::BasicBlock *BB) {
550   llvm::BranchInst *BI = dyn_cast<llvm::BranchInst>(BB->getTerminator());
551 
552   // If there is a cleanup stack, then we it isn't worth trying to
553   // simplify this block (we would need to remove it from the scope map
554   // and cleanup entry).
555   if (!EHStack.empty())
556     return;
557 
558   // Can only simplify direct branches.
559   if (!BI || !BI->isUnconditional())
560     return;
561 
562   // Can only simplify empty blocks.
563   if (BI->getIterator() != BB->begin())
564     return;
565 
566   BB->replaceAllUsesWith(BI->getSuccessor(0));
567   BI->eraseFromParent();
568   BB->eraseFromParent();
569 }
570 
571 void CodeGenFunction::EmitBlock(llvm::BasicBlock *BB, bool IsFinished) {
572   llvm::BasicBlock *CurBB = Builder.GetInsertBlock();
573 
574   // Fall out of the current block (if necessary).
575   EmitBranch(BB);
576 
577   if (IsFinished && BB->use_empty()) {
578     delete BB;
579     return;
580   }
581 
582   // Place the block after the current block, if possible, or else at
583   // the end of the function.
584   if (CurBB && CurBB->getParent())
585     CurFn->insert(std::next(CurBB->getIterator()), BB);
586   else
587     CurFn->insert(CurFn->end(), BB);
588   Builder.SetInsertPoint(BB);
589 }
590 
591 void CodeGenFunction::EmitBranch(llvm::BasicBlock *Target) {
592   // Emit a branch from the current block to the target one if this
593   // was a real block.  If this was just a fall-through block after a
594   // terminator, don't emit it.
595   llvm::BasicBlock *CurBB = Builder.GetInsertBlock();
596 
597   if (!CurBB || CurBB->getTerminator()) {
598     // If there is no insert point or the previous block is already
599     // terminated, don't touch it.
600   } else {
601     // Otherwise, create a fall-through branch.
602     Builder.CreateBr(Target);
603   }
604 
605   Builder.ClearInsertionPoint();
606 }
607 
608 void CodeGenFunction::EmitBlockAfterUses(llvm::BasicBlock *block) {
609   bool inserted = false;
610   for (llvm::User *u : block->users()) {
611     if (llvm::Instruction *insn = dyn_cast<llvm::Instruction>(u)) {
612       CurFn->insert(std::next(insn->getParent()->getIterator()), block);
613       inserted = true;
614       break;
615     }
616   }
617 
618   if (!inserted)
619     CurFn->insert(CurFn->end(), block);
620 
621   Builder.SetInsertPoint(block);
622 }
623 
624 CodeGenFunction::JumpDest
625 CodeGenFunction::getJumpDestForLabel(const LabelDecl *D) {
626   JumpDest &Dest = LabelMap[D];
627   if (Dest.isValid()) return Dest;
628 
629   // Create, but don't insert, the new block.
630   Dest = JumpDest(createBasicBlock(D->getName()),
631                   EHScopeStack::stable_iterator::invalid(),
632                   NextCleanupDestIndex++);
633   return Dest;
634 }
635 
636 void CodeGenFunction::EmitLabel(const LabelDecl *D) {
637   // Add this label to the current lexical scope if we're within any
638   // normal cleanups.  Jumps "in" to this label --- when permitted by
639   // the language --- may need to be routed around such cleanups.
640   if (EHStack.hasNormalCleanups() && CurLexicalScope)
641     CurLexicalScope->addLabel(D);
642 
643   JumpDest &Dest = LabelMap[D];
644 
645   // If we didn't need a forward reference to this label, just go
646   // ahead and create a destination at the current scope.
647   if (!Dest.isValid()) {
648     Dest = getJumpDestInCurrentScope(D->getName());
649 
650   // Otherwise, we need to give this label a target depth and remove
651   // it from the branch-fixups list.
652   } else {
653     assert(!Dest.getScopeDepth().isValid() && "already emitted label!");
654     Dest.setScopeDepth(EHStack.stable_begin());
655     ResolveBranchFixups(Dest.getBlock());
656   }
657 
658   EmitBlock(Dest.getBlock());
659 
660   // Emit debug info for labels.
661   if (CGDebugInfo *DI = getDebugInfo()) {
662     if (CGM.getCodeGenOpts().hasReducedDebugInfo()) {
663       DI->setLocation(D->getLocation());
664       DI->EmitLabel(D, Builder);
665     }
666   }
667 
668   incrementProfileCounter(D->getStmt());
669 }
670 
671 /// Change the cleanup scope of the labels in this lexical scope to
672 /// match the scope of the enclosing context.
673 void CodeGenFunction::LexicalScope::rescopeLabels() {
674   assert(!Labels.empty());
675   EHScopeStack::stable_iterator innermostScope
676     = CGF.EHStack.getInnermostNormalCleanup();
677 
678   // Change the scope depth of all the labels.
679   for (SmallVectorImpl<const LabelDecl*>::const_iterator
680          i = Labels.begin(), e = Labels.end(); i != e; ++i) {
681     assert(CGF.LabelMap.count(*i));
682     JumpDest &dest = CGF.LabelMap.find(*i)->second;
683     assert(dest.getScopeDepth().isValid());
684     assert(innermostScope.encloses(dest.getScopeDepth()));
685     dest.setScopeDepth(innermostScope);
686   }
687 
688   // Reparent the labels if the new scope also has cleanups.
689   if (innermostScope != EHScopeStack::stable_end() && ParentScope) {
690     ParentScope->Labels.append(Labels.begin(), Labels.end());
691   }
692 }
693 
694 
695 void CodeGenFunction::EmitLabelStmt(const LabelStmt &S) {
696   EmitLabel(S.getDecl());
697 
698   // IsEHa - emit eha.scope.begin if it's a side entry of a scope
699   if (getLangOpts().EHAsynch && S.isSideEntry())
700     EmitSehCppScopeBegin();
701 
702   EmitStmt(S.getSubStmt());
703 }
704 
705 void CodeGenFunction::EmitAttributedStmt(const AttributedStmt &S) {
706   bool nomerge = false;
707   bool noinline = false;
708   bool alwaysinline = false;
709   const CallExpr *musttail = nullptr;
710 
711   for (const auto *A : S.getAttrs()) {
712     switch (A->getKind()) {
713     default:
714       break;
715     case attr::NoMerge:
716       nomerge = true;
717       break;
718     case attr::NoInline:
719       noinline = true;
720       break;
721     case attr::AlwaysInline:
722       alwaysinline = true;
723       break;
724     case attr::MustTail:
725       const Stmt *Sub = S.getSubStmt();
726       const ReturnStmt *R = cast<ReturnStmt>(Sub);
727       musttail = cast<CallExpr>(R->getRetValue()->IgnoreParens());
728       break;
729     }
730   }
731   SaveAndRestore save_nomerge(InNoMergeAttributedStmt, nomerge);
732   SaveAndRestore save_noinline(InNoInlineAttributedStmt, noinline);
733   SaveAndRestore save_alwaysinline(InAlwaysInlineAttributedStmt, alwaysinline);
734   SaveAndRestore save_musttail(MustTailCall, musttail);
735   EmitStmt(S.getSubStmt(), S.getAttrs());
736 }
737 
738 void CodeGenFunction::EmitGotoStmt(const GotoStmt &S) {
739   // If this code is reachable then emit a stop point (if generating
740   // debug info). We have to do this ourselves because we are on the
741   // "simple" statement path.
742   if (HaveInsertPoint())
743     EmitStopPoint(&S);
744 
745   EmitBranchThroughCleanup(getJumpDestForLabel(S.getLabel()));
746 }
747 
748 
749 void CodeGenFunction::EmitIndirectGotoStmt(const IndirectGotoStmt &S) {
750   if (const LabelDecl *Target = S.getConstantTarget()) {
751     EmitBranchThroughCleanup(getJumpDestForLabel(Target));
752     return;
753   }
754 
755   // Ensure that we have an i8* for our PHI node.
756   llvm::Value *V = Builder.CreateBitCast(EmitScalarExpr(S.getTarget()),
757                                          Int8PtrTy, "addr");
758   llvm::BasicBlock *CurBB = Builder.GetInsertBlock();
759 
760   // Get the basic block for the indirect goto.
761   llvm::BasicBlock *IndGotoBB = GetIndirectGotoBlock();
762 
763   // The first instruction in the block has to be the PHI for the switch dest,
764   // add an entry for this branch.
765   cast<llvm::PHINode>(IndGotoBB->begin())->addIncoming(V, CurBB);
766 
767   EmitBranch(IndGotoBB);
768 }
769 
770 void CodeGenFunction::EmitIfStmt(const IfStmt &S) {
771   // The else branch of a consteval if statement is always the only branch that
772   // can be runtime evaluated.
773   if (S.isConsteval()) {
774     const Stmt *Executed = S.isNegatedConsteval() ? S.getThen() : S.getElse();
775     if (Executed) {
776       RunCleanupsScope ExecutedScope(*this);
777       EmitStmt(Executed);
778     }
779     return;
780   }
781 
782   // C99 6.8.4.1: The first substatement is executed if the expression compares
783   // unequal to 0.  The condition must be a scalar type.
784   LexicalScope ConditionScope(*this, S.getCond()->getSourceRange());
785 
786   if (S.getInit())
787     EmitStmt(S.getInit());
788 
789   if (S.getConditionVariable())
790     EmitDecl(*S.getConditionVariable());
791 
792   // If the condition constant folds and can be elided, try to avoid emitting
793   // the condition and the dead arm of the if/else.
794   bool CondConstant;
795   if (ConstantFoldsToSimpleInteger(S.getCond(), CondConstant,
796                                    S.isConstexpr())) {
797     // Figure out which block (then or else) is executed.
798     const Stmt *Executed = S.getThen();
799     const Stmt *Skipped  = S.getElse();
800     if (!CondConstant)  // Condition false?
801       std::swap(Executed, Skipped);
802 
803     // If the skipped block has no labels in it, just emit the executed block.
804     // This avoids emitting dead code and simplifies the CFG substantially.
805     if (S.isConstexpr() || !ContainsLabel(Skipped)) {
806       if (CondConstant)
807         incrementProfileCounter(&S);
808       if (Executed) {
809         RunCleanupsScope ExecutedScope(*this);
810         EmitStmt(Executed);
811       }
812       return;
813     }
814   }
815 
816   // Otherwise, the condition did not fold, or we couldn't elide it.  Just emit
817   // the conditional branch.
818   llvm::BasicBlock *ThenBlock = createBasicBlock("if.then");
819   llvm::BasicBlock *ContBlock = createBasicBlock("if.end");
820   llvm::BasicBlock *ElseBlock = ContBlock;
821   if (S.getElse())
822     ElseBlock = createBasicBlock("if.else");
823 
824   // Prefer the PGO based weights over the likelihood attribute.
825   // When the build isn't optimized the metadata isn't used, so don't generate
826   // it.
827   // Also, differentiate between disabled PGO and a never executed branch with
828   // PGO. Assuming PGO is in use:
829   // - we want to ignore the [[likely]] attribute if the branch is never
830   // executed,
831   // - assuming the profile is poor, preserving the attribute may still be
832   // beneficial.
833   // As an approximation, preserve the attribute only if both the branch and the
834   // parent context were not executed.
835   Stmt::Likelihood LH = Stmt::LH_None;
836   uint64_t ThenCount = getProfileCount(S.getThen());
837   if (!ThenCount && !getCurrentProfileCount() &&
838       CGM.getCodeGenOpts().OptimizationLevel)
839     LH = Stmt::getLikelihood(S.getThen(), S.getElse());
840   EmitBranchOnBoolExpr(S.getCond(), ThenBlock, ElseBlock, ThenCount, LH);
841 
842   // Emit the 'then' code.
843   EmitBlock(ThenBlock);
844   incrementProfileCounter(&S);
845   {
846     RunCleanupsScope ThenScope(*this);
847     EmitStmt(S.getThen());
848   }
849   EmitBranch(ContBlock);
850 
851   // Emit the 'else' code if present.
852   if (const Stmt *Else = S.getElse()) {
853     {
854       // There is no need to emit line number for an unconditional branch.
855       auto NL = ApplyDebugLocation::CreateEmpty(*this);
856       EmitBlock(ElseBlock);
857     }
858     {
859       RunCleanupsScope ElseScope(*this);
860       EmitStmt(Else);
861     }
862     {
863       // There is no need to emit line number for an unconditional branch.
864       auto NL = ApplyDebugLocation::CreateEmpty(*this);
865       EmitBranch(ContBlock);
866     }
867   }
868 
869   // Emit the continuation block for code after the if.
870   EmitBlock(ContBlock, true);
871 }
872 
873 void CodeGenFunction::EmitWhileStmt(const WhileStmt &S,
874                                     ArrayRef<const Attr *> WhileAttrs) {
875   // Emit the header for the loop, which will also become
876   // the continue target.
877   JumpDest LoopHeader = getJumpDestInCurrentScope("while.cond");
878   EmitBlock(LoopHeader.getBlock());
879 
880   // Create an exit block for when the condition fails, which will
881   // also become the break target.
882   JumpDest LoopExit = getJumpDestInCurrentScope("while.end");
883 
884   // Store the blocks to use for break and continue.
885   BreakContinueStack.push_back(BreakContinue(LoopExit, LoopHeader));
886 
887   // C++ [stmt.while]p2:
888   //   When the condition of a while statement is a declaration, the
889   //   scope of the variable that is declared extends from its point
890   //   of declaration (3.3.2) to the end of the while statement.
891   //   [...]
892   //   The object created in a condition is destroyed and created
893   //   with each iteration of the loop.
894   RunCleanupsScope ConditionScope(*this);
895 
896   if (S.getConditionVariable())
897     EmitDecl(*S.getConditionVariable());
898 
899   // Evaluate the conditional in the while header.  C99 6.8.5.1: The
900   // evaluation of the controlling expression takes place before each
901   // execution of the loop body.
902   llvm::Value *BoolCondVal = EvaluateExprAsBool(S.getCond());
903 
904   // while(1) is common, avoid extra exit blocks.  Be sure
905   // to correctly handle break/continue though.
906   llvm::ConstantInt *C = dyn_cast<llvm::ConstantInt>(BoolCondVal);
907   bool CondIsConstInt = C != nullptr;
908   bool EmitBoolCondBranch = !CondIsConstInt || !C->isOne();
909   const SourceRange &R = S.getSourceRange();
910   LoopStack.push(LoopHeader.getBlock(), CGM.getContext(), CGM.getCodeGenOpts(),
911                  WhileAttrs, SourceLocToDebugLoc(R.getBegin()),
912                  SourceLocToDebugLoc(R.getEnd()),
913                  checkIfLoopMustProgress(CondIsConstInt));
914 
915   // As long as the condition is true, go to the loop body.
916   llvm::BasicBlock *LoopBody = createBasicBlock("while.body");
917   if (EmitBoolCondBranch) {
918     llvm::BasicBlock *ExitBlock = LoopExit.getBlock();
919     if (ConditionScope.requiresCleanups())
920       ExitBlock = createBasicBlock("while.exit");
921     llvm::MDNode *Weights =
922         createProfileWeightsForLoop(S.getCond(), getProfileCount(S.getBody()));
923     if (!Weights && CGM.getCodeGenOpts().OptimizationLevel)
924       BoolCondVal = emitCondLikelihoodViaExpectIntrinsic(
925           BoolCondVal, Stmt::getLikelihood(S.getBody()));
926     Builder.CreateCondBr(BoolCondVal, LoopBody, ExitBlock, Weights);
927 
928     if (ExitBlock != LoopExit.getBlock()) {
929       EmitBlock(ExitBlock);
930       EmitBranchThroughCleanup(LoopExit);
931     }
932   } else if (const Attr *A = Stmt::getLikelihoodAttr(S.getBody())) {
933     CGM.getDiags().Report(A->getLocation(),
934                           diag::warn_attribute_has_no_effect_on_infinite_loop)
935         << A << A->getRange();
936     CGM.getDiags().Report(
937         S.getWhileLoc(),
938         diag::note_attribute_has_no_effect_on_infinite_loop_here)
939         << SourceRange(S.getWhileLoc(), S.getRParenLoc());
940   }
941 
942   // Emit the loop body.  We have to emit this in a cleanup scope
943   // because it might be a singleton DeclStmt.
944   {
945     RunCleanupsScope BodyScope(*this);
946     EmitBlock(LoopBody);
947     incrementProfileCounter(&S);
948     EmitStmt(S.getBody());
949   }
950 
951   BreakContinueStack.pop_back();
952 
953   // Immediately force cleanup.
954   ConditionScope.ForceCleanup();
955 
956   EmitStopPoint(&S);
957   // Branch to the loop header again.
958   EmitBranch(LoopHeader.getBlock());
959 
960   LoopStack.pop();
961 
962   // Emit the exit block.
963   EmitBlock(LoopExit.getBlock(), true);
964 
965   // The LoopHeader typically is just a branch if we skipped emitting
966   // a branch, try to erase it.
967   if (!EmitBoolCondBranch)
968     SimplifyForwardingBlocks(LoopHeader.getBlock());
969 }
970 
971 void CodeGenFunction::EmitDoStmt(const DoStmt &S,
972                                  ArrayRef<const Attr *> DoAttrs) {
973   JumpDest LoopExit = getJumpDestInCurrentScope("do.end");
974   JumpDest LoopCond = getJumpDestInCurrentScope("do.cond");
975 
976   uint64_t ParentCount = getCurrentProfileCount();
977 
978   // Store the blocks to use for break and continue.
979   BreakContinueStack.push_back(BreakContinue(LoopExit, LoopCond));
980 
981   // Emit the body of the loop.
982   llvm::BasicBlock *LoopBody = createBasicBlock("do.body");
983 
984   EmitBlockWithFallThrough(LoopBody, &S);
985   {
986     RunCleanupsScope BodyScope(*this);
987     EmitStmt(S.getBody());
988   }
989 
990   EmitBlock(LoopCond.getBlock());
991 
992   // C99 6.8.5.2: "The evaluation of the controlling expression takes place
993   // after each execution of the loop body."
994 
995   // Evaluate the conditional in the while header.
996   // C99 6.8.5p2/p4: The first substatement is executed if the expression
997   // compares unequal to 0.  The condition must be a scalar type.
998   llvm::Value *BoolCondVal = EvaluateExprAsBool(S.getCond());
999 
1000   BreakContinueStack.pop_back();
1001 
1002   // "do {} while (0)" is common in macros, avoid extra blocks.  Be sure
1003   // to correctly handle break/continue though.
1004   llvm::ConstantInt *C = dyn_cast<llvm::ConstantInt>(BoolCondVal);
1005   bool CondIsConstInt = C;
1006   bool EmitBoolCondBranch = !C || !C->isZero();
1007 
1008   const SourceRange &R = S.getSourceRange();
1009   LoopStack.push(LoopBody, CGM.getContext(), CGM.getCodeGenOpts(), DoAttrs,
1010                  SourceLocToDebugLoc(R.getBegin()),
1011                  SourceLocToDebugLoc(R.getEnd()),
1012                  checkIfLoopMustProgress(CondIsConstInt));
1013 
1014   // As long as the condition is true, iterate the loop.
1015   if (EmitBoolCondBranch) {
1016     uint64_t BackedgeCount = getProfileCount(S.getBody()) - ParentCount;
1017     Builder.CreateCondBr(
1018         BoolCondVal, LoopBody, LoopExit.getBlock(),
1019         createProfileWeightsForLoop(S.getCond(), BackedgeCount));
1020   }
1021 
1022   LoopStack.pop();
1023 
1024   // Emit the exit block.
1025   EmitBlock(LoopExit.getBlock());
1026 
1027   // The DoCond block typically is just a branch if we skipped
1028   // emitting a branch, try to erase it.
1029   if (!EmitBoolCondBranch)
1030     SimplifyForwardingBlocks(LoopCond.getBlock());
1031 }
1032 
1033 void CodeGenFunction::EmitForStmt(const ForStmt &S,
1034                                   ArrayRef<const Attr *> ForAttrs) {
1035   JumpDest LoopExit = getJumpDestInCurrentScope("for.end");
1036 
1037   LexicalScope ForScope(*this, S.getSourceRange());
1038 
1039   // Evaluate the first part before the loop.
1040   if (S.getInit())
1041     EmitStmt(S.getInit());
1042 
1043   // Start the loop with a block that tests the condition.
1044   // If there's an increment, the continue scope will be overwritten
1045   // later.
1046   JumpDest CondDest = getJumpDestInCurrentScope("for.cond");
1047   llvm::BasicBlock *CondBlock = CondDest.getBlock();
1048   EmitBlock(CondBlock);
1049 
1050   Expr::EvalResult Result;
1051   bool CondIsConstInt =
1052       !S.getCond() || S.getCond()->EvaluateAsInt(Result, getContext());
1053 
1054   const SourceRange &R = S.getSourceRange();
1055   LoopStack.push(CondBlock, CGM.getContext(), CGM.getCodeGenOpts(), ForAttrs,
1056                  SourceLocToDebugLoc(R.getBegin()),
1057                  SourceLocToDebugLoc(R.getEnd()),
1058                  checkIfLoopMustProgress(CondIsConstInt));
1059 
1060   // Create a cleanup scope for the condition variable cleanups.
1061   LexicalScope ConditionScope(*this, S.getSourceRange());
1062 
1063   // If the for loop doesn't have an increment we can just use the condition as
1064   // the continue block. Otherwise, if there is no condition variable, we can
1065   // form the continue block now. If there is a condition variable, we can't
1066   // form the continue block until after we've emitted the condition, because
1067   // the condition is in scope in the increment, but Sema's jump diagnostics
1068   // ensure that there are no continues from the condition variable that jump
1069   // to the loop increment.
1070   JumpDest Continue;
1071   if (!S.getInc())
1072     Continue = CondDest;
1073   else if (!S.getConditionVariable())
1074     Continue = getJumpDestInCurrentScope("for.inc");
1075   BreakContinueStack.push_back(BreakContinue(LoopExit, Continue));
1076 
1077   if (S.getCond()) {
1078     // If the for statement has a condition scope, emit the local variable
1079     // declaration.
1080     if (S.getConditionVariable()) {
1081       EmitDecl(*S.getConditionVariable());
1082 
1083       // We have entered the condition variable's scope, so we're now able to
1084       // jump to the continue block.
1085       Continue = S.getInc() ? getJumpDestInCurrentScope("for.inc") : CondDest;
1086       BreakContinueStack.back().ContinueBlock = Continue;
1087     }
1088 
1089     llvm::BasicBlock *ExitBlock = LoopExit.getBlock();
1090     // If there are any cleanups between here and the loop-exit scope,
1091     // create a block to stage a loop exit along.
1092     if (ForScope.requiresCleanups())
1093       ExitBlock = createBasicBlock("for.cond.cleanup");
1094 
1095     // As long as the condition is true, iterate the loop.
1096     llvm::BasicBlock *ForBody = createBasicBlock("for.body");
1097 
1098     // C99 6.8.5p2/p4: The first substatement is executed if the expression
1099     // compares unequal to 0.  The condition must be a scalar type.
1100     llvm::Value *BoolCondVal = EvaluateExprAsBool(S.getCond());
1101     llvm::MDNode *Weights =
1102         createProfileWeightsForLoop(S.getCond(), getProfileCount(S.getBody()));
1103     if (!Weights && CGM.getCodeGenOpts().OptimizationLevel)
1104       BoolCondVal = emitCondLikelihoodViaExpectIntrinsic(
1105           BoolCondVal, Stmt::getLikelihood(S.getBody()));
1106 
1107     Builder.CreateCondBr(BoolCondVal, ForBody, ExitBlock, Weights);
1108 
1109     if (ExitBlock != LoopExit.getBlock()) {
1110       EmitBlock(ExitBlock);
1111       EmitBranchThroughCleanup(LoopExit);
1112     }
1113 
1114     EmitBlock(ForBody);
1115   } else {
1116     // Treat it as a non-zero constant.  Don't even create a new block for the
1117     // body, just fall into it.
1118   }
1119   incrementProfileCounter(&S);
1120 
1121   {
1122     // Create a separate cleanup scope for the body, in case it is not
1123     // a compound statement.
1124     RunCleanupsScope BodyScope(*this);
1125     EmitStmt(S.getBody());
1126   }
1127 
1128   // If there is an increment, emit it next.
1129   if (S.getInc()) {
1130     EmitBlock(Continue.getBlock());
1131     EmitStmt(S.getInc());
1132   }
1133 
1134   BreakContinueStack.pop_back();
1135 
1136   ConditionScope.ForceCleanup();
1137 
1138   EmitStopPoint(&S);
1139   EmitBranch(CondBlock);
1140 
1141   ForScope.ForceCleanup();
1142 
1143   LoopStack.pop();
1144 
1145   // Emit the fall-through block.
1146   EmitBlock(LoopExit.getBlock(), true);
1147 }
1148 
1149 void
1150 CodeGenFunction::EmitCXXForRangeStmt(const CXXForRangeStmt &S,
1151                                      ArrayRef<const Attr *> ForAttrs) {
1152   JumpDest LoopExit = getJumpDestInCurrentScope("for.end");
1153 
1154   LexicalScope ForScope(*this, S.getSourceRange());
1155 
1156   // Evaluate the first pieces before the loop.
1157   if (S.getInit())
1158     EmitStmt(S.getInit());
1159   EmitStmt(S.getRangeStmt());
1160   EmitStmt(S.getBeginStmt());
1161   EmitStmt(S.getEndStmt());
1162 
1163   // Start the loop with a block that tests the condition.
1164   // If there's an increment, the continue scope will be overwritten
1165   // later.
1166   llvm::BasicBlock *CondBlock = createBasicBlock("for.cond");
1167   EmitBlock(CondBlock);
1168 
1169   const SourceRange &R = S.getSourceRange();
1170   LoopStack.push(CondBlock, CGM.getContext(), CGM.getCodeGenOpts(), ForAttrs,
1171                  SourceLocToDebugLoc(R.getBegin()),
1172                  SourceLocToDebugLoc(R.getEnd()));
1173 
1174   // If there are any cleanups between here and the loop-exit scope,
1175   // create a block to stage a loop exit along.
1176   llvm::BasicBlock *ExitBlock = LoopExit.getBlock();
1177   if (ForScope.requiresCleanups())
1178     ExitBlock = createBasicBlock("for.cond.cleanup");
1179 
1180   // The loop body, consisting of the specified body and the loop variable.
1181   llvm::BasicBlock *ForBody = createBasicBlock("for.body");
1182 
1183   // The body is executed if the expression, contextually converted
1184   // to bool, is true.
1185   llvm::Value *BoolCondVal = EvaluateExprAsBool(S.getCond());
1186   llvm::MDNode *Weights =
1187       createProfileWeightsForLoop(S.getCond(), getProfileCount(S.getBody()));
1188   if (!Weights && CGM.getCodeGenOpts().OptimizationLevel)
1189     BoolCondVal = emitCondLikelihoodViaExpectIntrinsic(
1190         BoolCondVal, Stmt::getLikelihood(S.getBody()));
1191   Builder.CreateCondBr(BoolCondVal, ForBody, ExitBlock, Weights);
1192 
1193   if (ExitBlock != LoopExit.getBlock()) {
1194     EmitBlock(ExitBlock);
1195     EmitBranchThroughCleanup(LoopExit);
1196   }
1197 
1198   EmitBlock(ForBody);
1199   incrementProfileCounter(&S);
1200 
1201   // Create a block for the increment. In case of a 'continue', we jump there.
1202   JumpDest Continue = getJumpDestInCurrentScope("for.inc");
1203 
1204   // Store the blocks to use for break and continue.
1205   BreakContinueStack.push_back(BreakContinue(LoopExit, Continue));
1206 
1207   {
1208     // Create a separate cleanup scope for the loop variable and body.
1209     LexicalScope BodyScope(*this, S.getSourceRange());
1210     EmitStmt(S.getLoopVarStmt());
1211     EmitStmt(S.getBody());
1212   }
1213 
1214   EmitStopPoint(&S);
1215   // If there is an increment, emit it next.
1216   EmitBlock(Continue.getBlock());
1217   EmitStmt(S.getInc());
1218 
1219   BreakContinueStack.pop_back();
1220 
1221   EmitBranch(CondBlock);
1222 
1223   ForScope.ForceCleanup();
1224 
1225   LoopStack.pop();
1226 
1227   // Emit the fall-through block.
1228   EmitBlock(LoopExit.getBlock(), true);
1229 }
1230 
1231 void CodeGenFunction::EmitReturnOfRValue(RValue RV, QualType Ty) {
1232   if (RV.isScalar()) {
1233     Builder.CreateStore(RV.getScalarVal(), ReturnValue);
1234   } else if (RV.isAggregate()) {
1235     LValue Dest = MakeAddrLValue(ReturnValue, Ty);
1236     LValue Src = MakeAddrLValue(RV.getAggregateAddress(), Ty);
1237     EmitAggregateCopy(Dest, Src, Ty, getOverlapForReturnValue());
1238   } else {
1239     EmitStoreOfComplex(RV.getComplexVal(), MakeAddrLValue(ReturnValue, Ty),
1240                        /*init*/ true);
1241   }
1242   EmitBranchThroughCleanup(ReturnBlock);
1243 }
1244 
1245 namespace {
1246 // RAII struct used to save and restore a return statment's result expression.
1247 struct SaveRetExprRAII {
1248   SaveRetExprRAII(const Expr *RetExpr, CodeGenFunction &CGF)
1249       : OldRetExpr(CGF.RetExpr), CGF(CGF) {
1250     CGF.RetExpr = RetExpr;
1251   }
1252   ~SaveRetExprRAII() { CGF.RetExpr = OldRetExpr; }
1253   const Expr *OldRetExpr;
1254   CodeGenFunction &CGF;
1255 };
1256 } // namespace
1257 
1258 /// If we have 'return f(...);', where both caller and callee are SwiftAsync,
1259 /// codegen it as 'tail call ...; ret void;'.
1260 static void makeTailCallIfSwiftAsync(const CallExpr *CE, CGBuilderTy &Builder,
1261                                      const CGFunctionInfo *CurFnInfo) {
1262   auto calleeQualType = CE->getCallee()->getType();
1263   const FunctionType *calleeType = nullptr;
1264   if (calleeQualType->isFunctionPointerType() ||
1265       calleeQualType->isFunctionReferenceType() ||
1266       calleeQualType->isBlockPointerType() ||
1267       calleeQualType->isMemberFunctionPointerType()) {
1268     calleeType = calleeQualType->getPointeeType()->castAs<FunctionType>();
1269   } else if (auto *ty = dyn_cast<FunctionType>(calleeQualType)) {
1270     calleeType = ty;
1271   } else if (auto CMCE = dyn_cast<CXXMemberCallExpr>(CE)) {
1272     if (auto methodDecl = CMCE->getMethodDecl()) {
1273       // getMethodDecl() doesn't handle member pointers at the moment.
1274       calleeType = methodDecl->getType()->castAs<FunctionType>();
1275     } else {
1276       return;
1277     }
1278   } else {
1279     return;
1280   }
1281   if (calleeType->getCallConv() == CallingConv::CC_SwiftAsync &&
1282       (CurFnInfo->getASTCallingConvention() == CallingConv::CC_SwiftAsync)) {
1283     auto CI = cast<llvm::CallInst>(&Builder.GetInsertBlock()->back());
1284     CI->setTailCallKind(llvm::CallInst::TCK_MustTail);
1285     Builder.CreateRetVoid();
1286     Builder.ClearInsertionPoint();
1287   }
1288 }
1289 
1290 /// EmitReturnStmt - Note that due to GCC extensions, this can have an operand
1291 /// if the function returns void, or may be missing one if the function returns
1292 /// non-void.  Fun stuff :).
1293 void CodeGenFunction::EmitReturnStmt(const ReturnStmt &S) {
1294   if (requiresReturnValueCheck()) {
1295     llvm::Constant *SLoc = EmitCheckSourceLocation(S.getBeginLoc());
1296     auto *SLocPtr =
1297         new llvm::GlobalVariable(CGM.getModule(), SLoc->getType(), false,
1298                                  llvm::GlobalVariable::PrivateLinkage, SLoc);
1299     SLocPtr->setUnnamedAddr(llvm::GlobalValue::UnnamedAddr::Global);
1300     CGM.getSanitizerMetadata()->disableSanitizerForGlobal(SLocPtr);
1301     assert(ReturnLocation.isValid() && "No valid return location");
1302     Builder.CreateStore(SLocPtr, ReturnLocation);
1303   }
1304 
1305   // Returning from an outlined SEH helper is UB, and we already warn on it.
1306   if (IsOutlinedSEHHelper) {
1307     Builder.CreateUnreachable();
1308     Builder.ClearInsertionPoint();
1309   }
1310 
1311   // Emit the result value, even if unused, to evaluate the side effects.
1312   const Expr *RV = S.getRetValue();
1313 
1314   // Record the result expression of the return statement. The recorded
1315   // expression is used to determine whether a block capture's lifetime should
1316   // end at the end of the full expression as opposed to the end of the scope
1317   // enclosing the block expression.
1318   //
1319   // This permits a small, easily-implemented exception to our over-conservative
1320   // rules about not jumping to statements following block literals with
1321   // non-trivial cleanups.
1322   SaveRetExprRAII SaveRetExpr(RV, *this);
1323 
1324   RunCleanupsScope cleanupScope(*this);
1325   if (const auto *EWC = dyn_cast_or_null<ExprWithCleanups>(RV))
1326     RV = EWC->getSubExpr();
1327   // FIXME: Clean this up by using an LValue for ReturnTemp,
1328   // EmitStoreThroughLValue, and EmitAnyExpr.
1329   // Check if the NRVO candidate was not globalized in OpenMP mode.
1330   if (getLangOpts().ElideConstructors && S.getNRVOCandidate() &&
1331       S.getNRVOCandidate()->isNRVOVariable() &&
1332       (!getLangOpts().OpenMP ||
1333        !CGM.getOpenMPRuntime()
1334             .getAddressOfLocalVariable(*this, S.getNRVOCandidate())
1335             .isValid())) {
1336     // Apply the named return value optimization for this return statement,
1337     // which means doing nothing: the appropriate result has already been
1338     // constructed into the NRVO variable.
1339 
1340     // If there is an NRVO flag for this variable, set it to 1 into indicate
1341     // that the cleanup code should not destroy the variable.
1342     if (llvm::Value *NRVOFlag = NRVOFlags[S.getNRVOCandidate()])
1343       Builder.CreateFlagStore(Builder.getTrue(), NRVOFlag);
1344   } else if (!ReturnValue.isValid() || (RV && RV->getType()->isVoidType())) {
1345     // Make sure not to return anything, but evaluate the expression
1346     // for side effects.
1347     if (RV) {
1348       EmitAnyExpr(RV);
1349       if (auto *CE = dyn_cast<CallExpr>(RV))
1350         makeTailCallIfSwiftAsync(CE, Builder, CurFnInfo);
1351     }
1352   } else if (!RV) {
1353     // Do nothing (return value is left uninitialized)
1354   } else if (FnRetTy->isReferenceType()) {
1355     // If this function returns a reference, take the address of the expression
1356     // rather than the value.
1357     RValue Result = EmitReferenceBindingToExpr(RV);
1358     Builder.CreateStore(Result.getScalarVal(), ReturnValue);
1359   } else {
1360     switch (getEvaluationKind(RV->getType())) {
1361     case TEK_Scalar:
1362       Builder.CreateStore(EmitScalarExpr(RV), ReturnValue);
1363       break;
1364     case TEK_Complex:
1365       EmitComplexExprIntoLValue(RV, MakeAddrLValue(ReturnValue, RV->getType()),
1366                                 /*isInit*/ true);
1367       break;
1368     case TEK_Aggregate:
1369       EmitAggExpr(RV, AggValueSlot::forAddr(
1370                           ReturnValue, Qualifiers(),
1371                           AggValueSlot::IsDestructed,
1372                           AggValueSlot::DoesNotNeedGCBarriers,
1373                           AggValueSlot::IsNotAliased,
1374                           getOverlapForReturnValue()));
1375       break;
1376     }
1377   }
1378 
1379   ++NumReturnExprs;
1380   if (!RV || RV->isEvaluatable(getContext()))
1381     ++NumSimpleReturnExprs;
1382 
1383   cleanupScope.ForceCleanup();
1384   EmitBranchThroughCleanup(ReturnBlock);
1385 }
1386 
1387 void CodeGenFunction::EmitDeclStmt(const DeclStmt &S) {
1388   // As long as debug info is modeled with instructions, we have to ensure we
1389   // have a place to insert here and write the stop point here.
1390   if (HaveInsertPoint())
1391     EmitStopPoint(&S);
1392 
1393   for (const auto *I : S.decls())
1394     EmitDecl(*I);
1395 }
1396 
1397 void CodeGenFunction::EmitBreakStmt(const BreakStmt &S) {
1398   assert(!BreakContinueStack.empty() && "break stmt not in a loop or switch!");
1399 
1400   // If this code is reachable then emit a stop point (if generating
1401   // debug info). We have to do this ourselves because we are on the
1402   // "simple" statement path.
1403   if (HaveInsertPoint())
1404     EmitStopPoint(&S);
1405 
1406   EmitBranchThroughCleanup(BreakContinueStack.back().BreakBlock);
1407 }
1408 
1409 void CodeGenFunction::EmitContinueStmt(const ContinueStmt &S) {
1410   assert(!BreakContinueStack.empty() && "continue stmt not in a loop!");
1411 
1412   // If this code is reachable then emit a stop point (if generating
1413   // debug info). We have to do this ourselves because we are on the
1414   // "simple" statement path.
1415   if (HaveInsertPoint())
1416     EmitStopPoint(&S);
1417 
1418   EmitBranchThroughCleanup(BreakContinueStack.back().ContinueBlock);
1419 }
1420 
1421 /// EmitCaseStmtRange - If case statement range is not too big then
1422 /// add multiple cases to switch instruction, one for each value within
1423 /// the range. If range is too big then emit "if" condition check.
1424 void CodeGenFunction::EmitCaseStmtRange(const CaseStmt &S,
1425                                         ArrayRef<const Attr *> Attrs) {
1426   assert(S.getRHS() && "Expected RHS value in CaseStmt");
1427 
1428   llvm::APSInt LHS = S.getLHS()->EvaluateKnownConstInt(getContext());
1429   llvm::APSInt RHS = S.getRHS()->EvaluateKnownConstInt(getContext());
1430 
1431   // Emit the code for this case. We do this first to make sure it is
1432   // properly chained from our predecessor before generating the
1433   // switch machinery to enter this block.
1434   llvm::BasicBlock *CaseDest = createBasicBlock("sw.bb");
1435   EmitBlockWithFallThrough(CaseDest, &S);
1436   EmitStmt(S.getSubStmt());
1437 
1438   // If range is empty, do nothing.
1439   if (LHS.isSigned() ? RHS.slt(LHS) : RHS.ult(LHS))
1440     return;
1441 
1442   Stmt::Likelihood LH = Stmt::getLikelihood(Attrs);
1443   llvm::APInt Range = RHS - LHS;
1444   // FIXME: parameters such as this should not be hardcoded.
1445   if (Range.ult(llvm::APInt(Range.getBitWidth(), 64))) {
1446     // Range is small enough to add multiple switch instruction cases.
1447     uint64_t Total = getProfileCount(&S);
1448     unsigned NCases = Range.getZExtValue() + 1;
1449     // We only have one region counter for the entire set of cases here, so we
1450     // need to divide the weights evenly between the generated cases, ensuring
1451     // that the total weight is preserved. E.g., a weight of 5 over three cases
1452     // will be distributed as weights of 2, 2, and 1.
1453     uint64_t Weight = Total / NCases, Rem = Total % NCases;
1454     for (unsigned I = 0; I != NCases; ++I) {
1455       if (SwitchWeights)
1456         SwitchWeights->push_back(Weight + (Rem ? 1 : 0));
1457       else if (SwitchLikelihood)
1458         SwitchLikelihood->push_back(LH);
1459 
1460       if (Rem)
1461         Rem--;
1462       SwitchInsn->addCase(Builder.getInt(LHS), CaseDest);
1463       ++LHS;
1464     }
1465     return;
1466   }
1467 
1468   // The range is too big. Emit "if" condition into a new block,
1469   // making sure to save and restore the current insertion point.
1470   llvm::BasicBlock *RestoreBB = Builder.GetInsertBlock();
1471 
1472   // Push this test onto the chain of range checks (which terminates
1473   // in the default basic block). The switch's default will be changed
1474   // to the top of this chain after switch emission is complete.
1475   llvm::BasicBlock *FalseDest = CaseRangeBlock;
1476   CaseRangeBlock = createBasicBlock("sw.caserange");
1477 
1478   CurFn->insert(CurFn->end(), CaseRangeBlock);
1479   Builder.SetInsertPoint(CaseRangeBlock);
1480 
1481   // Emit range check.
1482   llvm::Value *Diff =
1483     Builder.CreateSub(SwitchInsn->getCondition(), Builder.getInt(LHS));
1484   llvm::Value *Cond =
1485     Builder.CreateICmpULE(Diff, Builder.getInt(Range), "inbounds");
1486 
1487   llvm::MDNode *Weights = nullptr;
1488   if (SwitchWeights) {
1489     uint64_t ThisCount = getProfileCount(&S);
1490     uint64_t DefaultCount = (*SwitchWeights)[0];
1491     Weights = createProfileWeights(ThisCount, DefaultCount);
1492 
1493     // Since we're chaining the switch default through each large case range, we
1494     // need to update the weight for the default, ie, the first case, to include
1495     // this case.
1496     (*SwitchWeights)[0] += ThisCount;
1497   } else if (SwitchLikelihood)
1498     Cond = emitCondLikelihoodViaExpectIntrinsic(Cond, LH);
1499 
1500   Builder.CreateCondBr(Cond, CaseDest, FalseDest, Weights);
1501 
1502   // Restore the appropriate insertion point.
1503   if (RestoreBB)
1504     Builder.SetInsertPoint(RestoreBB);
1505   else
1506     Builder.ClearInsertionPoint();
1507 }
1508 
1509 void CodeGenFunction::EmitCaseStmt(const CaseStmt &S,
1510                                    ArrayRef<const Attr *> Attrs) {
1511   // If there is no enclosing switch instance that we're aware of, then this
1512   // case statement and its block can be elided.  This situation only happens
1513   // when we've constant-folded the switch, are emitting the constant case,
1514   // and part of the constant case includes another case statement.  For
1515   // instance: switch (4) { case 4: do { case 5: } while (1); }
1516   if (!SwitchInsn) {
1517     EmitStmt(S.getSubStmt());
1518     return;
1519   }
1520 
1521   // Handle case ranges.
1522   if (S.getRHS()) {
1523     EmitCaseStmtRange(S, Attrs);
1524     return;
1525   }
1526 
1527   llvm::ConstantInt *CaseVal =
1528     Builder.getInt(S.getLHS()->EvaluateKnownConstInt(getContext()));
1529 
1530   // Emit debuginfo for the case value if it is an enum value.
1531   const ConstantExpr *CE;
1532   if (auto ICE = dyn_cast<ImplicitCastExpr>(S.getLHS()))
1533     CE = dyn_cast<ConstantExpr>(ICE->getSubExpr());
1534   else
1535     CE = dyn_cast<ConstantExpr>(S.getLHS());
1536   if (CE) {
1537     if (auto DE = dyn_cast<DeclRefExpr>(CE->getSubExpr()))
1538       if (CGDebugInfo *Dbg = getDebugInfo())
1539         if (CGM.getCodeGenOpts().hasReducedDebugInfo())
1540           Dbg->EmitGlobalVariable(DE->getDecl(),
1541               APValue(llvm::APSInt(CaseVal->getValue())));
1542   }
1543 
1544   if (SwitchLikelihood)
1545     SwitchLikelihood->push_back(Stmt::getLikelihood(Attrs));
1546 
1547   // If the body of the case is just a 'break', try to not emit an empty block.
1548   // If we're profiling or we're not optimizing, leave the block in for better
1549   // debug and coverage analysis.
1550   if (!CGM.getCodeGenOpts().hasProfileClangInstr() &&
1551       CGM.getCodeGenOpts().OptimizationLevel > 0 &&
1552       isa<BreakStmt>(S.getSubStmt())) {
1553     JumpDest Block = BreakContinueStack.back().BreakBlock;
1554 
1555     // Only do this optimization if there are no cleanups that need emitting.
1556     if (isObviouslyBranchWithoutCleanups(Block)) {
1557       if (SwitchWeights)
1558         SwitchWeights->push_back(getProfileCount(&S));
1559       SwitchInsn->addCase(CaseVal, Block.getBlock());
1560 
1561       // If there was a fallthrough into this case, make sure to redirect it to
1562       // the end of the switch as well.
1563       if (Builder.GetInsertBlock()) {
1564         Builder.CreateBr(Block.getBlock());
1565         Builder.ClearInsertionPoint();
1566       }
1567       return;
1568     }
1569   }
1570 
1571   llvm::BasicBlock *CaseDest = createBasicBlock("sw.bb");
1572   EmitBlockWithFallThrough(CaseDest, &S);
1573   if (SwitchWeights)
1574     SwitchWeights->push_back(getProfileCount(&S));
1575   SwitchInsn->addCase(CaseVal, CaseDest);
1576 
1577   // Recursively emitting the statement is acceptable, but is not wonderful for
1578   // code where we have many case statements nested together, i.e.:
1579   //  case 1:
1580   //    case 2:
1581   //      case 3: etc.
1582   // Handling this recursively will create a new block for each case statement
1583   // that falls through to the next case which is IR intensive.  It also causes
1584   // deep recursion which can run into stack depth limitations.  Handle
1585   // sequential non-range case statements specially.
1586   //
1587   // TODO When the next case has a likelihood attribute the code returns to the
1588   // recursive algorithm. Maybe improve this case if it becomes common practice
1589   // to use a lot of attributes.
1590   const CaseStmt *CurCase = &S;
1591   const CaseStmt *NextCase = dyn_cast<CaseStmt>(S.getSubStmt());
1592 
1593   // Otherwise, iteratively add consecutive cases to this switch stmt.
1594   while (NextCase && NextCase->getRHS() == nullptr) {
1595     CurCase = NextCase;
1596     llvm::ConstantInt *CaseVal =
1597       Builder.getInt(CurCase->getLHS()->EvaluateKnownConstInt(getContext()));
1598 
1599     if (SwitchWeights)
1600       SwitchWeights->push_back(getProfileCount(NextCase));
1601     if (CGM.getCodeGenOpts().hasProfileClangInstr()) {
1602       CaseDest = createBasicBlock("sw.bb");
1603       EmitBlockWithFallThrough(CaseDest, CurCase);
1604     }
1605     // Since this loop is only executed when the CaseStmt has no attributes
1606     // use a hard-coded value.
1607     if (SwitchLikelihood)
1608       SwitchLikelihood->push_back(Stmt::LH_None);
1609 
1610     SwitchInsn->addCase(CaseVal, CaseDest);
1611     NextCase = dyn_cast<CaseStmt>(CurCase->getSubStmt());
1612   }
1613 
1614   // Generate a stop point for debug info if the case statement is
1615   // followed by a default statement. A fallthrough case before a
1616   // default case gets its own branch target.
1617   if (CurCase->getSubStmt()->getStmtClass() == Stmt::DefaultStmtClass)
1618     EmitStopPoint(CurCase);
1619 
1620   // Normal default recursion for non-cases.
1621   EmitStmt(CurCase->getSubStmt());
1622 }
1623 
1624 void CodeGenFunction::EmitDefaultStmt(const DefaultStmt &S,
1625                                       ArrayRef<const Attr *> Attrs) {
1626   // If there is no enclosing switch instance that we're aware of, then this
1627   // default statement can be elided. This situation only happens when we've
1628   // constant-folded the switch.
1629   if (!SwitchInsn) {
1630     EmitStmt(S.getSubStmt());
1631     return;
1632   }
1633 
1634   llvm::BasicBlock *DefaultBlock = SwitchInsn->getDefaultDest();
1635   assert(DefaultBlock->empty() &&
1636          "EmitDefaultStmt: Default block already defined?");
1637 
1638   if (SwitchLikelihood)
1639     SwitchLikelihood->front() = Stmt::getLikelihood(Attrs);
1640 
1641   EmitBlockWithFallThrough(DefaultBlock, &S);
1642 
1643   EmitStmt(S.getSubStmt());
1644 }
1645 
1646 /// CollectStatementsForCase - Given the body of a 'switch' statement and a
1647 /// constant value that is being switched on, see if we can dead code eliminate
1648 /// the body of the switch to a simple series of statements to emit.  Basically,
1649 /// on a switch (5) we want to find these statements:
1650 ///    case 5:
1651 ///      printf(...);    <--
1652 ///      ++i;            <--
1653 ///      break;
1654 ///
1655 /// and add them to the ResultStmts vector.  If it is unsafe to do this
1656 /// transformation (for example, one of the elided statements contains a label
1657 /// that might be jumped to), return CSFC_Failure.  If we handled it and 'S'
1658 /// should include statements after it (e.g. the printf() line is a substmt of
1659 /// the case) then return CSFC_FallThrough.  If we handled it and found a break
1660 /// statement, then return CSFC_Success.
1661 ///
1662 /// If Case is non-null, then we are looking for the specified case, checking
1663 /// that nothing we jump over contains labels.  If Case is null, then we found
1664 /// the case and are looking for the break.
1665 ///
1666 /// If the recursive walk actually finds our Case, then we set FoundCase to
1667 /// true.
1668 ///
1669 enum CSFC_Result { CSFC_Failure, CSFC_FallThrough, CSFC_Success };
1670 static CSFC_Result CollectStatementsForCase(const Stmt *S,
1671                                             const SwitchCase *Case,
1672                                             bool &FoundCase,
1673                               SmallVectorImpl<const Stmt*> &ResultStmts) {
1674   // If this is a null statement, just succeed.
1675   if (!S)
1676     return Case ? CSFC_Success : CSFC_FallThrough;
1677 
1678   // If this is the switchcase (case 4: or default) that we're looking for, then
1679   // we're in business.  Just add the substatement.
1680   if (const SwitchCase *SC = dyn_cast<SwitchCase>(S)) {
1681     if (S == Case) {
1682       FoundCase = true;
1683       return CollectStatementsForCase(SC->getSubStmt(), nullptr, FoundCase,
1684                                       ResultStmts);
1685     }
1686 
1687     // Otherwise, this is some other case or default statement, just ignore it.
1688     return CollectStatementsForCase(SC->getSubStmt(), Case, FoundCase,
1689                                     ResultStmts);
1690   }
1691 
1692   // If we are in the live part of the code and we found our break statement,
1693   // return a success!
1694   if (!Case && isa<BreakStmt>(S))
1695     return CSFC_Success;
1696 
1697   // If this is a switch statement, then it might contain the SwitchCase, the
1698   // break, or neither.
1699   if (const CompoundStmt *CS = dyn_cast<CompoundStmt>(S)) {
1700     // Handle this as two cases: we might be looking for the SwitchCase (if so
1701     // the skipped statements must be skippable) or we might already have it.
1702     CompoundStmt::const_body_iterator I = CS->body_begin(), E = CS->body_end();
1703     bool StartedInLiveCode = FoundCase;
1704     unsigned StartSize = ResultStmts.size();
1705 
1706     // If we've not found the case yet, scan through looking for it.
1707     if (Case) {
1708       // Keep track of whether we see a skipped declaration.  The code could be
1709       // using the declaration even if it is skipped, so we can't optimize out
1710       // the decl if the kept statements might refer to it.
1711       bool HadSkippedDecl = false;
1712 
1713       // If we're looking for the case, just see if we can skip each of the
1714       // substatements.
1715       for (; Case && I != E; ++I) {
1716         HadSkippedDecl |= CodeGenFunction::mightAddDeclToScope(*I);
1717 
1718         switch (CollectStatementsForCase(*I, Case, FoundCase, ResultStmts)) {
1719         case CSFC_Failure: return CSFC_Failure;
1720         case CSFC_Success:
1721           // A successful result means that either 1) that the statement doesn't
1722           // have the case and is skippable, or 2) does contain the case value
1723           // and also contains the break to exit the switch.  In the later case,
1724           // we just verify the rest of the statements are elidable.
1725           if (FoundCase) {
1726             // If we found the case and skipped declarations, we can't do the
1727             // optimization.
1728             if (HadSkippedDecl)
1729               return CSFC_Failure;
1730 
1731             for (++I; I != E; ++I)
1732               if (CodeGenFunction::ContainsLabel(*I, true))
1733                 return CSFC_Failure;
1734             return CSFC_Success;
1735           }
1736           break;
1737         case CSFC_FallThrough:
1738           // If we have a fallthrough condition, then we must have found the
1739           // case started to include statements.  Consider the rest of the
1740           // statements in the compound statement as candidates for inclusion.
1741           assert(FoundCase && "Didn't find case but returned fallthrough?");
1742           // We recursively found Case, so we're not looking for it anymore.
1743           Case = nullptr;
1744 
1745           // If we found the case and skipped declarations, we can't do the
1746           // optimization.
1747           if (HadSkippedDecl)
1748             return CSFC_Failure;
1749           break;
1750         }
1751       }
1752 
1753       if (!FoundCase)
1754         return CSFC_Success;
1755 
1756       assert(!HadSkippedDecl && "fallthrough after skipping decl");
1757     }
1758 
1759     // If we have statements in our range, then we know that the statements are
1760     // live and need to be added to the set of statements we're tracking.
1761     bool AnyDecls = false;
1762     for (; I != E; ++I) {
1763       AnyDecls |= CodeGenFunction::mightAddDeclToScope(*I);
1764 
1765       switch (CollectStatementsForCase(*I, nullptr, FoundCase, ResultStmts)) {
1766       case CSFC_Failure: return CSFC_Failure;
1767       case CSFC_FallThrough:
1768         // A fallthrough result means that the statement was simple and just
1769         // included in ResultStmt, keep adding them afterwards.
1770         break;
1771       case CSFC_Success:
1772         // A successful result means that we found the break statement and
1773         // stopped statement inclusion.  We just ensure that any leftover stmts
1774         // are skippable and return success ourselves.
1775         for (++I; I != E; ++I)
1776           if (CodeGenFunction::ContainsLabel(*I, true))
1777             return CSFC_Failure;
1778         return CSFC_Success;
1779       }
1780     }
1781 
1782     // If we're about to fall out of a scope without hitting a 'break;', we
1783     // can't perform the optimization if there were any decls in that scope
1784     // (we'd lose their end-of-lifetime).
1785     if (AnyDecls) {
1786       // If the entire compound statement was live, there's one more thing we
1787       // can try before giving up: emit the whole thing as a single statement.
1788       // We can do that unless the statement contains a 'break;'.
1789       // FIXME: Such a break must be at the end of a construct within this one.
1790       // We could emit this by just ignoring the BreakStmts entirely.
1791       if (StartedInLiveCode && !CodeGenFunction::containsBreak(S)) {
1792         ResultStmts.resize(StartSize);
1793         ResultStmts.push_back(S);
1794       } else {
1795         return CSFC_Failure;
1796       }
1797     }
1798 
1799     return CSFC_FallThrough;
1800   }
1801 
1802   // Okay, this is some other statement that we don't handle explicitly, like a
1803   // for statement or increment etc.  If we are skipping over this statement,
1804   // just verify it doesn't have labels, which would make it invalid to elide.
1805   if (Case) {
1806     if (CodeGenFunction::ContainsLabel(S, true))
1807       return CSFC_Failure;
1808     return CSFC_Success;
1809   }
1810 
1811   // Otherwise, we want to include this statement.  Everything is cool with that
1812   // so long as it doesn't contain a break out of the switch we're in.
1813   if (CodeGenFunction::containsBreak(S)) return CSFC_Failure;
1814 
1815   // Otherwise, everything is great.  Include the statement and tell the caller
1816   // that we fall through and include the next statement as well.
1817   ResultStmts.push_back(S);
1818   return CSFC_FallThrough;
1819 }
1820 
1821 /// FindCaseStatementsForValue - Find the case statement being jumped to and
1822 /// then invoke CollectStatementsForCase to find the list of statements to emit
1823 /// for a switch on constant.  See the comment above CollectStatementsForCase
1824 /// for more details.
1825 static bool FindCaseStatementsForValue(const SwitchStmt &S,
1826                                        const llvm::APSInt &ConstantCondValue,
1827                                 SmallVectorImpl<const Stmt*> &ResultStmts,
1828                                        ASTContext &C,
1829                                        const SwitchCase *&ResultCase) {
1830   // First step, find the switch case that is being branched to.  We can do this
1831   // efficiently by scanning the SwitchCase list.
1832   const SwitchCase *Case = S.getSwitchCaseList();
1833   const DefaultStmt *DefaultCase = nullptr;
1834 
1835   for (; Case; Case = Case->getNextSwitchCase()) {
1836     // It's either a default or case.  Just remember the default statement in
1837     // case we're not jumping to any numbered cases.
1838     if (const DefaultStmt *DS = dyn_cast<DefaultStmt>(Case)) {
1839       DefaultCase = DS;
1840       continue;
1841     }
1842 
1843     // Check to see if this case is the one we're looking for.
1844     const CaseStmt *CS = cast<CaseStmt>(Case);
1845     // Don't handle case ranges yet.
1846     if (CS->getRHS()) return false;
1847 
1848     // If we found our case, remember it as 'case'.
1849     if (CS->getLHS()->EvaluateKnownConstInt(C) == ConstantCondValue)
1850       break;
1851   }
1852 
1853   // If we didn't find a matching case, we use a default if it exists, or we
1854   // elide the whole switch body!
1855   if (!Case) {
1856     // It is safe to elide the body of the switch if it doesn't contain labels
1857     // etc.  If it is safe, return successfully with an empty ResultStmts list.
1858     if (!DefaultCase)
1859       return !CodeGenFunction::ContainsLabel(&S);
1860     Case = DefaultCase;
1861   }
1862 
1863   // Ok, we know which case is being jumped to, try to collect all the
1864   // statements that follow it.  This can fail for a variety of reasons.  Also,
1865   // check to see that the recursive walk actually found our case statement.
1866   // Insane cases like this can fail to find it in the recursive walk since we
1867   // don't handle every stmt kind:
1868   // switch (4) {
1869   //   while (1) {
1870   //     case 4: ...
1871   bool FoundCase = false;
1872   ResultCase = Case;
1873   return CollectStatementsForCase(S.getBody(), Case, FoundCase,
1874                                   ResultStmts) != CSFC_Failure &&
1875          FoundCase;
1876 }
1877 
1878 static std::optional<SmallVector<uint64_t, 16>>
1879 getLikelihoodWeights(ArrayRef<Stmt::Likelihood> Likelihoods) {
1880   // Are there enough branches to weight them?
1881   if (Likelihoods.size() <= 1)
1882     return std::nullopt;
1883 
1884   uint64_t NumUnlikely = 0;
1885   uint64_t NumNone = 0;
1886   uint64_t NumLikely = 0;
1887   for (const auto LH : Likelihoods) {
1888     switch (LH) {
1889     case Stmt::LH_Unlikely:
1890       ++NumUnlikely;
1891       break;
1892     case Stmt::LH_None:
1893       ++NumNone;
1894       break;
1895     case Stmt::LH_Likely:
1896       ++NumLikely;
1897       break;
1898     }
1899   }
1900 
1901   // Is there a likelihood attribute used?
1902   if (NumUnlikely == 0 && NumLikely == 0)
1903     return std::nullopt;
1904 
1905   // When multiple cases share the same code they can be combined during
1906   // optimization. In that case the weights of the branch will be the sum of
1907   // the individual weights. Make sure the combined sum of all neutral cases
1908   // doesn't exceed the value of a single likely attribute.
1909   // The additions both avoid divisions by 0 and make sure the weights of None
1910   // don't exceed the weight of Likely.
1911   const uint64_t Likely = INT32_MAX / (NumLikely + 2);
1912   const uint64_t None = Likely / (NumNone + 1);
1913   const uint64_t Unlikely = 0;
1914 
1915   SmallVector<uint64_t, 16> Result;
1916   Result.reserve(Likelihoods.size());
1917   for (const auto LH : Likelihoods) {
1918     switch (LH) {
1919     case Stmt::LH_Unlikely:
1920       Result.push_back(Unlikely);
1921       break;
1922     case Stmt::LH_None:
1923       Result.push_back(None);
1924       break;
1925     case Stmt::LH_Likely:
1926       Result.push_back(Likely);
1927       break;
1928     }
1929   }
1930 
1931   return Result;
1932 }
1933 
1934 void CodeGenFunction::EmitSwitchStmt(const SwitchStmt &S) {
1935   // Handle nested switch statements.
1936   llvm::SwitchInst *SavedSwitchInsn = SwitchInsn;
1937   SmallVector<uint64_t, 16> *SavedSwitchWeights = SwitchWeights;
1938   SmallVector<Stmt::Likelihood, 16> *SavedSwitchLikelihood = SwitchLikelihood;
1939   llvm::BasicBlock *SavedCRBlock = CaseRangeBlock;
1940 
1941   // See if we can constant fold the condition of the switch and therefore only
1942   // emit the live case statement (if any) of the switch.
1943   llvm::APSInt ConstantCondValue;
1944   if (ConstantFoldsToSimpleInteger(S.getCond(), ConstantCondValue)) {
1945     SmallVector<const Stmt*, 4> CaseStmts;
1946     const SwitchCase *Case = nullptr;
1947     if (FindCaseStatementsForValue(S, ConstantCondValue, CaseStmts,
1948                                    getContext(), Case)) {
1949       if (Case)
1950         incrementProfileCounter(Case);
1951       RunCleanupsScope ExecutedScope(*this);
1952 
1953       if (S.getInit())
1954         EmitStmt(S.getInit());
1955 
1956       // Emit the condition variable if needed inside the entire cleanup scope
1957       // used by this special case for constant folded switches.
1958       if (S.getConditionVariable())
1959         EmitDecl(*S.getConditionVariable());
1960 
1961       // At this point, we are no longer "within" a switch instance, so
1962       // we can temporarily enforce this to ensure that any embedded case
1963       // statements are not emitted.
1964       SwitchInsn = nullptr;
1965 
1966       // Okay, we can dead code eliminate everything except this case.  Emit the
1967       // specified series of statements and we're good.
1968       for (unsigned i = 0, e = CaseStmts.size(); i != e; ++i)
1969         EmitStmt(CaseStmts[i]);
1970       incrementProfileCounter(&S);
1971 
1972       // Now we want to restore the saved switch instance so that nested
1973       // switches continue to function properly
1974       SwitchInsn = SavedSwitchInsn;
1975 
1976       return;
1977     }
1978   }
1979 
1980   JumpDest SwitchExit = getJumpDestInCurrentScope("sw.epilog");
1981 
1982   RunCleanupsScope ConditionScope(*this);
1983 
1984   if (S.getInit())
1985     EmitStmt(S.getInit());
1986 
1987   if (S.getConditionVariable())
1988     EmitDecl(*S.getConditionVariable());
1989   llvm::Value *CondV = EmitScalarExpr(S.getCond());
1990 
1991   // Create basic block to hold stuff that comes after switch
1992   // statement. We also need to create a default block now so that
1993   // explicit case ranges tests can have a place to jump to on
1994   // failure.
1995   llvm::BasicBlock *DefaultBlock = createBasicBlock("sw.default");
1996   SwitchInsn = Builder.CreateSwitch(CondV, DefaultBlock);
1997   if (PGO.haveRegionCounts()) {
1998     // Walk the SwitchCase list to find how many there are.
1999     uint64_t DefaultCount = 0;
2000     unsigned NumCases = 0;
2001     for (const SwitchCase *Case = S.getSwitchCaseList();
2002          Case;
2003          Case = Case->getNextSwitchCase()) {
2004       if (isa<DefaultStmt>(Case))
2005         DefaultCount = getProfileCount(Case);
2006       NumCases += 1;
2007     }
2008     SwitchWeights = new SmallVector<uint64_t, 16>();
2009     SwitchWeights->reserve(NumCases);
2010     // The default needs to be first. We store the edge count, so we already
2011     // know the right weight.
2012     SwitchWeights->push_back(DefaultCount);
2013   } else if (CGM.getCodeGenOpts().OptimizationLevel) {
2014     SwitchLikelihood = new SmallVector<Stmt::Likelihood, 16>();
2015     // Initialize the default case.
2016     SwitchLikelihood->push_back(Stmt::LH_None);
2017   }
2018 
2019   CaseRangeBlock = DefaultBlock;
2020 
2021   // Clear the insertion point to indicate we are in unreachable code.
2022   Builder.ClearInsertionPoint();
2023 
2024   // All break statements jump to NextBlock. If BreakContinueStack is non-empty
2025   // then reuse last ContinueBlock.
2026   JumpDest OuterContinue;
2027   if (!BreakContinueStack.empty())
2028     OuterContinue = BreakContinueStack.back().ContinueBlock;
2029 
2030   BreakContinueStack.push_back(BreakContinue(SwitchExit, OuterContinue));
2031 
2032   // Emit switch body.
2033   EmitStmt(S.getBody());
2034 
2035   BreakContinueStack.pop_back();
2036 
2037   // Update the default block in case explicit case range tests have
2038   // been chained on top.
2039   SwitchInsn->setDefaultDest(CaseRangeBlock);
2040 
2041   // If a default was never emitted:
2042   if (!DefaultBlock->getParent()) {
2043     // If we have cleanups, emit the default block so that there's a
2044     // place to jump through the cleanups from.
2045     if (ConditionScope.requiresCleanups()) {
2046       EmitBlock(DefaultBlock);
2047 
2048     // Otherwise, just forward the default block to the switch end.
2049     } else {
2050       DefaultBlock->replaceAllUsesWith(SwitchExit.getBlock());
2051       delete DefaultBlock;
2052     }
2053   }
2054 
2055   ConditionScope.ForceCleanup();
2056 
2057   // Emit continuation.
2058   EmitBlock(SwitchExit.getBlock(), true);
2059   incrementProfileCounter(&S);
2060 
2061   // If the switch has a condition wrapped by __builtin_unpredictable,
2062   // create metadata that specifies that the switch is unpredictable.
2063   // Don't bother if not optimizing because that metadata would not be used.
2064   auto *Call = dyn_cast<CallExpr>(S.getCond());
2065   if (Call && CGM.getCodeGenOpts().OptimizationLevel != 0) {
2066     auto *FD = dyn_cast_or_null<FunctionDecl>(Call->getCalleeDecl());
2067     if (FD && FD->getBuiltinID() == Builtin::BI__builtin_unpredictable) {
2068       llvm::MDBuilder MDHelper(getLLVMContext());
2069       SwitchInsn->setMetadata(llvm::LLVMContext::MD_unpredictable,
2070                               MDHelper.createUnpredictable());
2071     }
2072   }
2073 
2074   if (SwitchWeights) {
2075     assert(SwitchWeights->size() == 1 + SwitchInsn->getNumCases() &&
2076            "switch weights do not match switch cases");
2077     // If there's only one jump destination there's no sense weighting it.
2078     if (SwitchWeights->size() > 1)
2079       SwitchInsn->setMetadata(llvm::LLVMContext::MD_prof,
2080                               createProfileWeights(*SwitchWeights));
2081     delete SwitchWeights;
2082   } else if (SwitchLikelihood) {
2083     assert(SwitchLikelihood->size() == 1 + SwitchInsn->getNumCases() &&
2084            "switch likelihoods do not match switch cases");
2085     std::optional<SmallVector<uint64_t, 16>> LHW =
2086         getLikelihoodWeights(*SwitchLikelihood);
2087     if (LHW) {
2088       llvm::MDBuilder MDHelper(CGM.getLLVMContext());
2089       SwitchInsn->setMetadata(llvm::LLVMContext::MD_prof,
2090                               createProfileWeights(*LHW));
2091     }
2092     delete SwitchLikelihood;
2093   }
2094   SwitchInsn = SavedSwitchInsn;
2095   SwitchWeights = SavedSwitchWeights;
2096   SwitchLikelihood = SavedSwitchLikelihood;
2097   CaseRangeBlock = SavedCRBlock;
2098 }
2099 
2100 static std::string
2101 SimplifyConstraint(const char *Constraint, const TargetInfo &Target,
2102                  SmallVectorImpl<TargetInfo::ConstraintInfo> *OutCons=nullptr) {
2103   std::string Result;
2104 
2105   while (*Constraint) {
2106     switch (*Constraint) {
2107     default:
2108       Result += Target.convertConstraint(Constraint);
2109       break;
2110     // Ignore these
2111     case '*':
2112     case '?':
2113     case '!':
2114     case '=': // Will see this and the following in mult-alt constraints.
2115     case '+':
2116       break;
2117     case '#': // Ignore the rest of the constraint alternative.
2118       while (Constraint[1] && Constraint[1] != ',')
2119         Constraint++;
2120       break;
2121     case '&':
2122     case '%':
2123       Result += *Constraint;
2124       while (Constraint[1] && Constraint[1] == *Constraint)
2125         Constraint++;
2126       break;
2127     case ',':
2128       Result += "|";
2129       break;
2130     case 'g':
2131       Result += "imr";
2132       break;
2133     case '[': {
2134       assert(OutCons &&
2135              "Must pass output names to constraints with a symbolic name");
2136       unsigned Index;
2137       bool result = Target.resolveSymbolicName(Constraint, *OutCons, Index);
2138       assert(result && "Could not resolve symbolic name"); (void)result;
2139       Result += llvm::utostr(Index);
2140       break;
2141     }
2142     }
2143 
2144     Constraint++;
2145   }
2146 
2147   return Result;
2148 }
2149 
2150 /// AddVariableConstraints - Look at AsmExpr and if it is a variable declared
2151 /// as using a particular register add that as a constraint that will be used
2152 /// in this asm stmt.
2153 static std::string
2154 AddVariableConstraints(const std::string &Constraint, const Expr &AsmExpr,
2155                        const TargetInfo &Target, CodeGenModule &CGM,
2156                        const AsmStmt &Stmt, const bool EarlyClobber,
2157                        std::string *GCCReg = nullptr) {
2158   const DeclRefExpr *AsmDeclRef = dyn_cast<DeclRefExpr>(&AsmExpr);
2159   if (!AsmDeclRef)
2160     return Constraint;
2161   const ValueDecl &Value = *AsmDeclRef->getDecl();
2162   const VarDecl *Variable = dyn_cast<VarDecl>(&Value);
2163   if (!Variable)
2164     return Constraint;
2165   if (Variable->getStorageClass() != SC_Register)
2166     return Constraint;
2167   AsmLabelAttr *Attr = Variable->getAttr<AsmLabelAttr>();
2168   if (!Attr)
2169     return Constraint;
2170   StringRef Register = Attr->getLabel();
2171   assert(Target.isValidGCCRegisterName(Register));
2172   // We're using validateOutputConstraint here because we only care if
2173   // this is a register constraint.
2174   TargetInfo::ConstraintInfo Info(Constraint, "");
2175   if (Target.validateOutputConstraint(Info) &&
2176       !Info.allowsRegister()) {
2177     CGM.ErrorUnsupported(&Stmt, "__asm__");
2178     return Constraint;
2179   }
2180   // Canonicalize the register here before returning it.
2181   Register = Target.getNormalizedGCCRegisterName(Register);
2182   if (GCCReg != nullptr)
2183     *GCCReg = Register.str();
2184   return (EarlyClobber ? "&{" : "{") + Register.str() + "}";
2185 }
2186 
2187 std::pair<llvm::Value*, llvm::Type *> CodeGenFunction::EmitAsmInputLValue(
2188     const TargetInfo::ConstraintInfo &Info, LValue InputValue,
2189     QualType InputType, std::string &ConstraintStr, SourceLocation Loc) {
2190   if (Info.allowsRegister() || !Info.allowsMemory()) {
2191     if (CodeGenFunction::hasScalarEvaluationKind(InputType))
2192       return {EmitLoadOfLValue(InputValue, Loc).getScalarVal(), nullptr};
2193 
2194     llvm::Type *Ty = ConvertType(InputType);
2195     uint64_t Size = CGM.getDataLayout().getTypeSizeInBits(Ty);
2196     if ((Size <= 64 && llvm::isPowerOf2_64(Size)) ||
2197         getTargetHooks().isScalarizableAsmOperand(*this, Ty)) {
2198       Ty = llvm::IntegerType::get(getLLVMContext(), Size);
2199 
2200       return {
2201           Builder.CreateLoad(InputValue.getAddress(*this).withElementType(Ty)),
2202           nullptr};
2203     }
2204   }
2205 
2206   Address Addr = InputValue.getAddress(*this);
2207   ConstraintStr += '*';
2208   return {Addr.getPointer(), Addr.getElementType()};
2209 }
2210 
2211 std::pair<llvm::Value *, llvm::Type *>
2212 CodeGenFunction::EmitAsmInput(const TargetInfo::ConstraintInfo &Info,
2213                               const Expr *InputExpr,
2214                               std::string &ConstraintStr) {
2215   // If this can't be a register or memory, i.e., has to be a constant
2216   // (immediate or symbolic), try to emit it as such.
2217   if (!Info.allowsRegister() && !Info.allowsMemory()) {
2218     if (Info.requiresImmediateConstant()) {
2219       Expr::EvalResult EVResult;
2220       InputExpr->EvaluateAsRValue(EVResult, getContext(), true);
2221 
2222       llvm::APSInt IntResult;
2223       if (EVResult.Val.toIntegralConstant(IntResult, InputExpr->getType(),
2224                                           getContext()))
2225         return {llvm::ConstantInt::get(getLLVMContext(), IntResult), nullptr};
2226     }
2227 
2228     Expr::EvalResult Result;
2229     if (InputExpr->EvaluateAsInt(Result, getContext()))
2230       return {llvm::ConstantInt::get(getLLVMContext(), Result.Val.getInt()),
2231               nullptr};
2232   }
2233 
2234   if (Info.allowsRegister() || !Info.allowsMemory())
2235     if (CodeGenFunction::hasScalarEvaluationKind(InputExpr->getType()))
2236       return {EmitScalarExpr(InputExpr), nullptr};
2237   if (InputExpr->getStmtClass() == Expr::CXXThisExprClass)
2238     return {EmitScalarExpr(InputExpr), nullptr};
2239   InputExpr = InputExpr->IgnoreParenNoopCasts(getContext());
2240   LValue Dest = EmitLValue(InputExpr);
2241   return EmitAsmInputLValue(Info, Dest, InputExpr->getType(), ConstraintStr,
2242                             InputExpr->getExprLoc());
2243 }
2244 
2245 /// getAsmSrcLocInfo - Return the !srcloc metadata node to attach to an inline
2246 /// asm call instruction.  The !srcloc MDNode contains a list of constant
2247 /// integers which are the source locations of the start of each line in the
2248 /// asm.
2249 static llvm::MDNode *getAsmSrcLocInfo(const StringLiteral *Str,
2250                                       CodeGenFunction &CGF) {
2251   SmallVector<llvm::Metadata *, 8> Locs;
2252   // Add the location of the first line to the MDNode.
2253   Locs.push_back(llvm::ConstantAsMetadata::get(llvm::ConstantInt::get(
2254       CGF.Int64Ty, Str->getBeginLoc().getRawEncoding())));
2255   StringRef StrVal = Str->getString();
2256   if (!StrVal.empty()) {
2257     const SourceManager &SM = CGF.CGM.getContext().getSourceManager();
2258     const LangOptions &LangOpts = CGF.CGM.getLangOpts();
2259     unsigned StartToken = 0;
2260     unsigned ByteOffset = 0;
2261 
2262     // Add the location of the start of each subsequent line of the asm to the
2263     // MDNode.
2264     for (unsigned i = 0, e = StrVal.size() - 1; i != e; ++i) {
2265       if (StrVal[i] != '\n') continue;
2266       SourceLocation LineLoc = Str->getLocationOfByte(
2267           i + 1, SM, LangOpts, CGF.getTarget(), &StartToken, &ByteOffset);
2268       Locs.push_back(llvm::ConstantAsMetadata::get(
2269           llvm::ConstantInt::get(CGF.Int64Ty, LineLoc.getRawEncoding())));
2270     }
2271   }
2272 
2273   return llvm::MDNode::get(CGF.getLLVMContext(), Locs);
2274 }
2275 
2276 static void UpdateAsmCallInst(llvm::CallBase &Result, bool HasSideEffect,
2277                               bool HasUnwindClobber, bool ReadOnly,
2278                               bool ReadNone, bool NoMerge, const AsmStmt &S,
2279                               const std::vector<llvm::Type *> &ResultRegTypes,
2280                               const std::vector<llvm::Type *> &ArgElemTypes,
2281                               CodeGenFunction &CGF,
2282                               std::vector<llvm::Value *> &RegResults) {
2283   if (!HasUnwindClobber)
2284     Result.addFnAttr(llvm::Attribute::NoUnwind);
2285 
2286   if (NoMerge)
2287     Result.addFnAttr(llvm::Attribute::NoMerge);
2288   // Attach readnone and readonly attributes.
2289   if (!HasSideEffect) {
2290     if (ReadNone)
2291       Result.setDoesNotAccessMemory();
2292     else if (ReadOnly)
2293       Result.setOnlyReadsMemory();
2294   }
2295 
2296   // Add elementtype attribute for indirect constraints.
2297   for (auto Pair : llvm::enumerate(ArgElemTypes)) {
2298     if (Pair.value()) {
2299       auto Attr = llvm::Attribute::get(
2300           CGF.getLLVMContext(), llvm::Attribute::ElementType, Pair.value());
2301       Result.addParamAttr(Pair.index(), Attr);
2302     }
2303   }
2304 
2305   // Slap the source location of the inline asm into a !srcloc metadata on the
2306   // call.
2307   if (const auto *gccAsmStmt = dyn_cast<GCCAsmStmt>(&S))
2308     Result.setMetadata("srcloc",
2309                        getAsmSrcLocInfo(gccAsmStmt->getAsmString(), CGF));
2310   else {
2311     // At least put the line number on MS inline asm blobs.
2312     llvm::Constant *Loc =
2313         llvm::ConstantInt::get(CGF.Int64Ty, S.getAsmLoc().getRawEncoding());
2314     Result.setMetadata("srcloc",
2315                        llvm::MDNode::get(CGF.getLLVMContext(),
2316                                          llvm::ConstantAsMetadata::get(Loc)));
2317   }
2318 
2319   if (CGF.getLangOpts().assumeFunctionsAreConvergent())
2320     // Conservatively, mark all inline asm blocks in CUDA or OpenCL as
2321     // convergent (meaning, they may call an intrinsically convergent op, such
2322     // as bar.sync, and so can't have certain optimizations applied around
2323     // them).
2324     Result.addFnAttr(llvm::Attribute::Convergent);
2325   // Extract all of the register value results from the asm.
2326   if (ResultRegTypes.size() == 1) {
2327     RegResults.push_back(&Result);
2328   } else {
2329     for (unsigned i = 0, e = ResultRegTypes.size(); i != e; ++i) {
2330       llvm::Value *Tmp = CGF.Builder.CreateExtractValue(&Result, i, "asmresult");
2331       RegResults.push_back(Tmp);
2332     }
2333   }
2334 }
2335 
2336 static void
2337 EmitAsmStores(CodeGenFunction &CGF, const AsmStmt &S,
2338               const llvm::ArrayRef<llvm::Value *> RegResults,
2339               const llvm::ArrayRef<llvm::Type *> ResultRegTypes,
2340               const llvm::ArrayRef<llvm::Type *> ResultTruncRegTypes,
2341               const llvm::ArrayRef<LValue> ResultRegDests,
2342               const llvm::ArrayRef<QualType> ResultRegQualTys,
2343               const llvm::BitVector &ResultTypeRequiresCast,
2344               const llvm::BitVector &ResultRegIsFlagReg) {
2345   CGBuilderTy &Builder = CGF.Builder;
2346   CodeGenModule &CGM = CGF.CGM;
2347   llvm::LLVMContext &CTX = CGF.getLLVMContext();
2348 
2349   assert(RegResults.size() == ResultRegTypes.size());
2350   assert(RegResults.size() == ResultTruncRegTypes.size());
2351   assert(RegResults.size() == ResultRegDests.size());
2352   // ResultRegDests can be also populated by addReturnRegisterOutputs() above,
2353   // in which case its size may grow.
2354   assert(ResultTypeRequiresCast.size() <= ResultRegDests.size());
2355   assert(ResultRegIsFlagReg.size() <= ResultRegDests.size());
2356 
2357   for (unsigned i = 0, e = RegResults.size(); i != e; ++i) {
2358     llvm::Value *Tmp = RegResults[i];
2359     llvm::Type *TruncTy = ResultTruncRegTypes[i];
2360 
2361     if ((i < ResultRegIsFlagReg.size()) && ResultRegIsFlagReg[i]) {
2362       // Target must guarantee the Value `Tmp` here is lowered to a boolean
2363       // value.
2364       llvm::Constant *Two = llvm::ConstantInt::get(Tmp->getType(), 2);
2365       llvm::Value *IsBooleanValue =
2366           Builder.CreateCmp(llvm::CmpInst::ICMP_ULT, Tmp, Two);
2367       llvm::Function *FnAssume = CGM.getIntrinsic(llvm::Intrinsic::assume);
2368       Builder.CreateCall(FnAssume, IsBooleanValue);
2369     }
2370 
2371     // If the result type of the LLVM IR asm doesn't match the result type of
2372     // the expression, do the conversion.
2373     if (ResultRegTypes[i] != TruncTy) {
2374 
2375       // Truncate the integer result to the right size, note that TruncTy can be
2376       // a pointer.
2377       if (TruncTy->isFloatingPointTy())
2378         Tmp = Builder.CreateFPTrunc(Tmp, TruncTy);
2379       else if (TruncTy->isPointerTy() && Tmp->getType()->isIntegerTy()) {
2380         uint64_t ResSize = CGM.getDataLayout().getTypeSizeInBits(TruncTy);
2381         Tmp = Builder.CreateTrunc(
2382             Tmp, llvm::IntegerType::get(CTX, (unsigned)ResSize));
2383         Tmp = Builder.CreateIntToPtr(Tmp, TruncTy);
2384       } else if (Tmp->getType()->isPointerTy() && TruncTy->isIntegerTy()) {
2385         uint64_t TmpSize =
2386             CGM.getDataLayout().getTypeSizeInBits(Tmp->getType());
2387         Tmp = Builder.CreatePtrToInt(
2388             Tmp, llvm::IntegerType::get(CTX, (unsigned)TmpSize));
2389         Tmp = Builder.CreateTrunc(Tmp, TruncTy);
2390       } else if (TruncTy->isIntegerTy()) {
2391         Tmp = Builder.CreateZExtOrTrunc(Tmp, TruncTy);
2392       } else if (TruncTy->isVectorTy()) {
2393         Tmp = Builder.CreateBitCast(Tmp, TruncTy);
2394       }
2395     }
2396 
2397     LValue Dest = ResultRegDests[i];
2398     // ResultTypeRequiresCast elements correspond to the first
2399     // ResultTypeRequiresCast.size() elements of RegResults.
2400     if ((i < ResultTypeRequiresCast.size()) && ResultTypeRequiresCast[i]) {
2401       unsigned Size = CGF.getContext().getTypeSize(ResultRegQualTys[i]);
2402       Address A = Dest.getAddress(CGF).withElementType(ResultRegTypes[i]);
2403       if (CGF.getTargetHooks().isScalarizableAsmOperand(CGF, TruncTy)) {
2404         Builder.CreateStore(Tmp, A);
2405         continue;
2406       }
2407 
2408       QualType Ty =
2409           CGF.getContext().getIntTypeForBitwidth(Size, /*Signed=*/false);
2410       if (Ty.isNull()) {
2411         const Expr *OutExpr = S.getOutputExpr(i);
2412         CGM.getDiags().Report(OutExpr->getExprLoc(),
2413                               diag::err_store_value_to_reg);
2414         return;
2415       }
2416       Dest = CGF.MakeAddrLValue(A, Ty);
2417     }
2418     CGF.EmitStoreThroughLValue(RValue::get(Tmp), Dest);
2419   }
2420 }
2421 
2422 static void EmitHipStdParUnsupportedAsm(CodeGenFunction *CGF,
2423                                         const AsmStmt &S) {
2424   constexpr auto Name = "__ASM__hipstdpar_unsupported";
2425 
2426   StringRef Asm;
2427   if (auto GCCAsm = dyn_cast<GCCAsmStmt>(&S))
2428     Asm = GCCAsm->getAsmString()->getString();
2429 
2430   auto &Ctx = CGF->CGM.getLLVMContext();
2431 
2432   auto StrTy = llvm::ConstantDataArray::getString(Ctx, Asm);
2433   auto FnTy = llvm::FunctionType::get(llvm::Type::getVoidTy(Ctx),
2434                                       {StrTy->getType()}, false);
2435   auto UBF = CGF->CGM.getModule().getOrInsertFunction(Name, FnTy);
2436 
2437   CGF->Builder.CreateCall(UBF, {StrTy});
2438 }
2439 
2440 void CodeGenFunction::EmitAsmStmt(const AsmStmt &S) {
2441   // Pop all cleanup blocks at the end of the asm statement.
2442   CodeGenFunction::RunCleanupsScope Cleanups(*this);
2443 
2444   // Assemble the final asm string.
2445   std::string AsmString = S.generateAsmString(getContext());
2446 
2447   // Get all the output and input constraints together.
2448   SmallVector<TargetInfo::ConstraintInfo, 4> OutputConstraintInfos;
2449   SmallVector<TargetInfo::ConstraintInfo, 4> InputConstraintInfos;
2450 
2451   bool IsHipStdPar = getLangOpts().HIPStdPar && getLangOpts().CUDAIsDevice;
2452   bool IsValidTargetAsm = true;
2453   for (unsigned i = 0, e = S.getNumOutputs(); i != e && IsValidTargetAsm; i++) {
2454     StringRef Name;
2455     if (const GCCAsmStmt *GAS = dyn_cast<GCCAsmStmt>(&S))
2456       Name = GAS->getOutputName(i);
2457     TargetInfo::ConstraintInfo Info(S.getOutputConstraint(i), Name);
2458     bool IsValid = getTarget().validateOutputConstraint(Info); (void)IsValid;
2459     if (IsHipStdPar && !IsValid)
2460       IsValidTargetAsm = false;
2461     else
2462       assert(IsValid && "Failed to parse output constraint");
2463     OutputConstraintInfos.push_back(Info);
2464   }
2465 
2466   for (unsigned i = 0, e = S.getNumInputs(); i != e && IsValidTargetAsm; i++) {
2467     StringRef Name;
2468     if (const GCCAsmStmt *GAS = dyn_cast<GCCAsmStmt>(&S))
2469       Name = GAS->getInputName(i);
2470     TargetInfo::ConstraintInfo Info(S.getInputConstraint(i), Name);
2471     bool IsValid =
2472       getTarget().validateInputConstraint(OutputConstraintInfos, Info);
2473     if (IsHipStdPar && !IsValid)
2474       IsValidTargetAsm = false;
2475     else
2476       assert(IsValid && "Failed to parse input constraint");
2477     InputConstraintInfos.push_back(Info);
2478   }
2479 
2480   if (!IsValidTargetAsm)
2481     return EmitHipStdParUnsupportedAsm(this, S);
2482 
2483   std::string Constraints;
2484 
2485   std::vector<LValue> ResultRegDests;
2486   std::vector<QualType> ResultRegQualTys;
2487   std::vector<llvm::Type *> ResultRegTypes;
2488   std::vector<llvm::Type *> ResultTruncRegTypes;
2489   std::vector<llvm::Type *> ArgTypes;
2490   std::vector<llvm::Type *> ArgElemTypes;
2491   std::vector<llvm::Value*> Args;
2492   llvm::BitVector ResultTypeRequiresCast;
2493   llvm::BitVector ResultRegIsFlagReg;
2494 
2495   // Keep track of inout constraints.
2496   std::string InOutConstraints;
2497   std::vector<llvm::Value*> InOutArgs;
2498   std::vector<llvm::Type*> InOutArgTypes;
2499   std::vector<llvm::Type*> InOutArgElemTypes;
2500 
2501   // Keep track of out constraints for tied input operand.
2502   std::vector<std::string> OutputConstraints;
2503 
2504   // Keep track of defined physregs.
2505   llvm::SmallSet<std::string, 8> PhysRegOutputs;
2506 
2507   // An inline asm can be marked readonly if it meets the following conditions:
2508   //  - it doesn't have any sideeffects
2509   //  - it doesn't clobber memory
2510   //  - it doesn't return a value by-reference
2511   // It can be marked readnone if it doesn't have any input memory constraints
2512   // in addition to meeting the conditions listed above.
2513   bool ReadOnly = true, ReadNone = true;
2514 
2515   for (unsigned i = 0, e = S.getNumOutputs(); i != e; i++) {
2516     TargetInfo::ConstraintInfo &Info = OutputConstraintInfos[i];
2517 
2518     // Simplify the output constraint.
2519     std::string OutputConstraint(S.getOutputConstraint(i));
2520     OutputConstraint = SimplifyConstraint(OutputConstraint.c_str() + 1,
2521                                           getTarget(), &OutputConstraintInfos);
2522 
2523     const Expr *OutExpr = S.getOutputExpr(i);
2524     OutExpr = OutExpr->IgnoreParenNoopCasts(getContext());
2525 
2526     std::string GCCReg;
2527     OutputConstraint = AddVariableConstraints(OutputConstraint, *OutExpr,
2528                                               getTarget(), CGM, S,
2529                                               Info.earlyClobber(),
2530                                               &GCCReg);
2531     // Give an error on multiple outputs to same physreg.
2532     if (!GCCReg.empty() && !PhysRegOutputs.insert(GCCReg).second)
2533       CGM.Error(S.getAsmLoc(), "multiple outputs to hard register: " + GCCReg);
2534 
2535     OutputConstraints.push_back(OutputConstraint);
2536     LValue Dest = EmitLValue(OutExpr);
2537     if (!Constraints.empty())
2538       Constraints += ',';
2539 
2540     // If this is a register output, then make the inline asm return it
2541     // by-value.  If this is a memory result, return the value by-reference.
2542     QualType QTy = OutExpr->getType();
2543     const bool IsScalarOrAggregate = hasScalarEvaluationKind(QTy) ||
2544                                      hasAggregateEvaluationKind(QTy);
2545     if (!Info.allowsMemory() && IsScalarOrAggregate) {
2546 
2547       Constraints += "=" + OutputConstraint;
2548       ResultRegQualTys.push_back(QTy);
2549       ResultRegDests.push_back(Dest);
2550 
2551       bool IsFlagReg = llvm::StringRef(OutputConstraint).starts_with("{@cc");
2552       ResultRegIsFlagReg.push_back(IsFlagReg);
2553 
2554       llvm::Type *Ty = ConvertTypeForMem(QTy);
2555       const bool RequiresCast = Info.allowsRegister() &&
2556           (getTargetHooks().isScalarizableAsmOperand(*this, Ty) ||
2557            Ty->isAggregateType());
2558 
2559       ResultTruncRegTypes.push_back(Ty);
2560       ResultTypeRequiresCast.push_back(RequiresCast);
2561 
2562       if (RequiresCast) {
2563         unsigned Size = getContext().getTypeSize(QTy);
2564         Ty = llvm::IntegerType::get(getLLVMContext(), Size);
2565       }
2566       ResultRegTypes.push_back(Ty);
2567       // If this output is tied to an input, and if the input is larger, then
2568       // we need to set the actual result type of the inline asm node to be the
2569       // same as the input type.
2570       if (Info.hasMatchingInput()) {
2571         unsigned InputNo;
2572         for (InputNo = 0; InputNo != S.getNumInputs(); ++InputNo) {
2573           TargetInfo::ConstraintInfo &Input = InputConstraintInfos[InputNo];
2574           if (Input.hasTiedOperand() && Input.getTiedOperand() == i)
2575             break;
2576         }
2577         assert(InputNo != S.getNumInputs() && "Didn't find matching input!");
2578 
2579         QualType InputTy = S.getInputExpr(InputNo)->getType();
2580         QualType OutputType = OutExpr->getType();
2581 
2582         uint64_t InputSize = getContext().getTypeSize(InputTy);
2583         if (getContext().getTypeSize(OutputType) < InputSize) {
2584           // Form the asm to return the value as a larger integer or fp type.
2585           ResultRegTypes.back() = ConvertType(InputTy);
2586         }
2587       }
2588       if (llvm::Type* AdjTy =
2589             getTargetHooks().adjustInlineAsmType(*this, OutputConstraint,
2590                                                  ResultRegTypes.back()))
2591         ResultRegTypes.back() = AdjTy;
2592       else {
2593         CGM.getDiags().Report(S.getAsmLoc(),
2594                               diag::err_asm_invalid_type_in_input)
2595             << OutExpr->getType() << OutputConstraint;
2596       }
2597 
2598       // Update largest vector width for any vector types.
2599       if (auto *VT = dyn_cast<llvm::VectorType>(ResultRegTypes.back()))
2600         LargestVectorWidth =
2601             std::max((uint64_t)LargestVectorWidth,
2602                      VT->getPrimitiveSizeInBits().getKnownMinValue());
2603     } else {
2604       Address DestAddr = Dest.getAddress(*this);
2605       // Matrix types in memory are represented by arrays, but accessed through
2606       // vector pointers, with the alignment specified on the access operation.
2607       // For inline assembly, update pointer arguments to use vector pointers.
2608       // Otherwise there will be a mis-match if the matrix is also an
2609       // input-argument which is represented as vector.
2610       if (isa<MatrixType>(OutExpr->getType().getCanonicalType()))
2611         DestAddr = DestAddr.withElementType(ConvertType(OutExpr->getType()));
2612 
2613       ArgTypes.push_back(DestAddr.getType());
2614       ArgElemTypes.push_back(DestAddr.getElementType());
2615       Args.push_back(DestAddr.getPointer());
2616       Constraints += "=*";
2617       Constraints += OutputConstraint;
2618       ReadOnly = ReadNone = false;
2619     }
2620 
2621     if (Info.isReadWrite()) {
2622       InOutConstraints += ',';
2623 
2624       const Expr *InputExpr = S.getOutputExpr(i);
2625       llvm::Value *Arg;
2626       llvm::Type *ArgElemType;
2627       std::tie(Arg, ArgElemType) = EmitAsmInputLValue(
2628           Info, Dest, InputExpr->getType(), InOutConstraints,
2629           InputExpr->getExprLoc());
2630 
2631       if (llvm::Type* AdjTy =
2632           getTargetHooks().adjustInlineAsmType(*this, OutputConstraint,
2633                                                Arg->getType()))
2634         Arg = Builder.CreateBitCast(Arg, AdjTy);
2635 
2636       // Update largest vector width for any vector types.
2637       if (auto *VT = dyn_cast<llvm::VectorType>(Arg->getType()))
2638         LargestVectorWidth =
2639             std::max((uint64_t)LargestVectorWidth,
2640                      VT->getPrimitiveSizeInBits().getKnownMinValue());
2641       // Only tie earlyclobber physregs.
2642       if (Info.allowsRegister() && (GCCReg.empty() || Info.earlyClobber()))
2643         InOutConstraints += llvm::utostr(i);
2644       else
2645         InOutConstraints += OutputConstraint;
2646 
2647       InOutArgTypes.push_back(Arg->getType());
2648       InOutArgElemTypes.push_back(ArgElemType);
2649       InOutArgs.push_back(Arg);
2650     }
2651   }
2652 
2653   // If this is a Microsoft-style asm blob, store the return registers (EAX:EDX)
2654   // to the return value slot. Only do this when returning in registers.
2655   if (isa<MSAsmStmt>(&S)) {
2656     const ABIArgInfo &RetAI = CurFnInfo->getReturnInfo();
2657     if (RetAI.isDirect() || RetAI.isExtend()) {
2658       // Make a fake lvalue for the return value slot.
2659       LValue ReturnSlot = MakeAddrLValueWithoutTBAA(ReturnValue, FnRetTy);
2660       CGM.getTargetCodeGenInfo().addReturnRegisterOutputs(
2661           *this, ReturnSlot, Constraints, ResultRegTypes, ResultTruncRegTypes,
2662           ResultRegDests, AsmString, S.getNumOutputs());
2663       SawAsmBlock = true;
2664     }
2665   }
2666 
2667   for (unsigned i = 0, e = S.getNumInputs(); i != e; i++) {
2668     const Expr *InputExpr = S.getInputExpr(i);
2669 
2670     TargetInfo::ConstraintInfo &Info = InputConstraintInfos[i];
2671 
2672     if (Info.allowsMemory())
2673       ReadNone = false;
2674 
2675     if (!Constraints.empty())
2676       Constraints += ',';
2677 
2678     // Simplify the input constraint.
2679     std::string InputConstraint(S.getInputConstraint(i));
2680     InputConstraint = SimplifyConstraint(InputConstraint.c_str(), getTarget(),
2681                                          &OutputConstraintInfos);
2682 
2683     InputConstraint = AddVariableConstraints(
2684         InputConstraint, *InputExpr->IgnoreParenNoopCasts(getContext()),
2685         getTarget(), CGM, S, false /* No EarlyClobber */);
2686 
2687     std::string ReplaceConstraint (InputConstraint);
2688     llvm::Value *Arg;
2689     llvm::Type *ArgElemType;
2690     std::tie(Arg, ArgElemType) = EmitAsmInput(Info, InputExpr, Constraints);
2691 
2692     // If this input argument is tied to a larger output result, extend the
2693     // input to be the same size as the output.  The LLVM backend wants to see
2694     // the input and output of a matching constraint be the same size.  Note
2695     // that GCC does not define what the top bits are here.  We use zext because
2696     // that is usually cheaper, but LLVM IR should really get an anyext someday.
2697     if (Info.hasTiedOperand()) {
2698       unsigned Output = Info.getTiedOperand();
2699       QualType OutputType = S.getOutputExpr(Output)->getType();
2700       QualType InputTy = InputExpr->getType();
2701 
2702       if (getContext().getTypeSize(OutputType) >
2703           getContext().getTypeSize(InputTy)) {
2704         // Use ptrtoint as appropriate so that we can do our extension.
2705         if (isa<llvm::PointerType>(Arg->getType()))
2706           Arg = Builder.CreatePtrToInt(Arg, IntPtrTy);
2707         llvm::Type *OutputTy = ConvertType(OutputType);
2708         if (isa<llvm::IntegerType>(OutputTy))
2709           Arg = Builder.CreateZExt(Arg, OutputTy);
2710         else if (isa<llvm::PointerType>(OutputTy))
2711           Arg = Builder.CreateZExt(Arg, IntPtrTy);
2712         else if (OutputTy->isFloatingPointTy())
2713           Arg = Builder.CreateFPExt(Arg, OutputTy);
2714       }
2715       // Deal with the tied operands' constraint code in adjustInlineAsmType.
2716       ReplaceConstraint = OutputConstraints[Output];
2717     }
2718     if (llvm::Type* AdjTy =
2719           getTargetHooks().adjustInlineAsmType(*this, ReplaceConstraint,
2720                                                    Arg->getType()))
2721       Arg = Builder.CreateBitCast(Arg, AdjTy);
2722     else
2723       CGM.getDiags().Report(S.getAsmLoc(), diag::err_asm_invalid_type_in_input)
2724           << InputExpr->getType() << InputConstraint;
2725 
2726     // Update largest vector width for any vector types.
2727     if (auto *VT = dyn_cast<llvm::VectorType>(Arg->getType()))
2728       LargestVectorWidth =
2729           std::max((uint64_t)LargestVectorWidth,
2730                    VT->getPrimitiveSizeInBits().getKnownMinValue());
2731 
2732     ArgTypes.push_back(Arg->getType());
2733     ArgElemTypes.push_back(ArgElemType);
2734     Args.push_back(Arg);
2735     Constraints += InputConstraint;
2736   }
2737 
2738   // Append the "input" part of inout constraints.
2739   for (unsigned i = 0, e = InOutArgs.size(); i != e; i++) {
2740     ArgTypes.push_back(InOutArgTypes[i]);
2741     ArgElemTypes.push_back(InOutArgElemTypes[i]);
2742     Args.push_back(InOutArgs[i]);
2743   }
2744   Constraints += InOutConstraints;
2745 
2746   // Labels
2747   SmallVector<llvm::BasicBlock *, 16> Transfer;
2748   llvm::BasicBlock *Fallthrough = nullptr;
2749   bool IsGCCAsmGoto = false;
2750   if (const auto *GS = dyn_cast<GCCAsmStmt>(&S)) {
2751     IsGCCAsmGoto = GS->isAsmGoto();
2752     if (IsGCCAsmGoto) {
2753       for (const auto *E : GS->labels()) {
2754         JumpDest Dest = getJumpDestForLabel(E->getLabel());
2755         Transfer.push_back(Dest.getBlock());
2756         if (!Constraints.empty())
2757           Constraints += ',';
2758         Constraints += "!i";
2759       }
2760       Fallthrough = createBasicBlock("asm.fallthrough");
2761     }
2762   }
2763 
2764   bool HasUnwindClobber = false;
2765 
2766   // Clobbers
2767   for (unsigned i = 0, e = S.getNumClobbers(); i != e; i++) {
2768     StringRef Clobber = S.getClobber(i);
2769 
2770     if (Clobber == "memory")
2771       ReadOnly = ReadNone = false;
2772     else if (Clobber == "unwind") {
2773       HasUnwindClobber = true;
2774       continue;
2775     } else if (Clobber != "cc") {
2776       Clobber = getTarget().getNormalizedGCCRegisterName(Clobber);
2777       if (CGM.getCodeGenOpts().StackClashProtector &&
2778           getTarget().isSPRegName(Clobber)) {
2779         CGM.getDiags().Report(S.getAsmLoc(),
2780                               diag::warn_stack_clash_protection_inline_asm);
2781       }
2782     }
2783 
2784     if (isa<MSAsmStmt>(&S)) {
2785       if (Clobber == "eax" || Clobber == "edx") {
2786         if (Constraints.find("=&A") != std::string::npos)
2787           continue;
2788         std::string::size_type position1 =
2789             Constraints.find("={" + Clobber.str() + "}");
2790         if (position1 != std::string::npos) {
2791           Constraints.insert(position1 + 1, "&");
2792           continue;
2793         }
2794         std::string::size_type position2 = Constraints.find("=A");
2795         if (position2 != std::string::npos) {
2796           Constraints.insert(position2 + 1, "&");
2797           continue;
2798         }
2799       }
2800     }
2801     if (!Constraints.empty())
2802       Constraints += ',';
2803 
2804     Constraints += "~{";
2805     Constraints += Clobber;
2806     Constraints += '}';
2807   }
2808 
2809   assert(!(HasUnwindClobber && IsGCCAsmGoto) &&
2810          "unwind clobber can't be used with asm goto");
2811 
2812   // Add machine specific clobbers
2813   std::string_view MachineClobbers = getTarget().getClobbers();
2814   if (!MachineClobbers.empty()) {
2815     if (!Constraints.empty())
2816       Constraints += ',';
2817     Constraints += MachineClobbers;
2818   }
2819 
2820   llvm::Type *ResultType;
2821   if (ResultRegTypes.empty())
2822     ResultType = VoidTy;
2823   else if (ResultRegTypes.size() == 1)
2824     ResultType = ResultRegTypes[0];
2825   else
2826     ResultType = llvm::StructType::get(getLLVMContext(), ResultRegTypes);
2827 
2828   llvm::FunctionType *FTy =
2829     llvm::FunctionType::get(ResultType, ArgTypes, false);
2830 
2831   bool HasSideEffect = S.isVolatile() || S.getNumOutputs() == 0;
2832 
2833   llvm::InlineAsm::AsmDialect GnuAsmDialect =
2834       CGM.getCodeGenOpts().getInlineAsmDialect() == CodeGenOptions::IAD_ATT
2835           ? llvm::InlineAsm::AD_ATT
2836           : llvm::InlineAsm::AD_Intel;
2837   llvm::InlineAsm::AsmDialect AsmDialect = isa<MSAsmStmt>(&S) ?
2838     llvm::InlineAsm::AD_Intel : GnuAsmDialect;
2839 
2840   llvm::InlineAsm *IA = llvm::InlineAsm::get(
2841       FTy, AsmString, Constraints, HasSideEffect,
2842       /* IsAlignStack */ false, AsmDialect, HasUnwindClobber);
2843   std::vector<llvm::Value*> RegResults;
2844   llvm::CallBrInst *CBR;
2845   llvm::DenseMap<llvm::BasicBlock *, SmallVector<llvm::Value *, 4>>
2846       CBRRegResults;
2847   if (IsGCCAsmGoto) {
2848     CBR = Builder.CreateCallBr(IA, Fallthrough, Transfer, Args);
2849     EmitBlock(Fallthrough);
2850     UpdateAsmCallInst(*CBR, HasSideEffect, false, ReadOnly, ReadNone,
2851                       InNoMergeAttributedStmt, S, ResultRegTypes, ArgElemTypes,
2852                       *this, RegResults);
2853     // Because we are emitting code top to bottom, we don't have enough
2854     // information at this point to know precisely whether we have a critical
2855     // edge. If we have outputs, split all indirect destinations.
2856     if (!RegResults.empty()) {
2857       unsigned i = 0;
2858       for (llvm::BasicBlock *Dest : CBR->getIndirectDests()) {
2859         llvm::Twine SynthName = Dest->getName() + ".split";
2860         llvm::BasicBlock *SynthBB = createBasicBlock(SynthName);
2861         llvm::IRBuilderBase::InsertPointGuard IPG(Builder);
2862         Builder.SetInsertPoint(SynthBB);
2863 
2864         if (ResultRegTypes.size() == 1) {
2865           CBRRegResults[SynthBB].push_back(CBR);
2866         } else {
2867           for (unsigned j = 0, e = ResultRegTypes.size(); j != e; ++j) {
2868             llvm::Value *Tmp = Builder.CreateExtractValue(CBR, j, "asmresult");
2869             CBRRegResults[SynthBB].push_back(Tmp);
2870           }
2871         }
2872 
2873         EmitBranch(Dest);
2874         EmitBlock(SynthBB);
2875         CBR->setIndirectDest(i++, SynthBB);
2876       }
2877     }
2878   } else if (HasUnwindClobber) {
2879     llvm::CallBase *Result = EmitCallOrInvoke(IA, Args, "");
2880     UpdateAsmCallInst(*Result, HasSideEffect, true, ReadOnly, ReadNone,
2881                       InNoMergeAttributedStmt, S, ResultRegTypes, ArgElemTypes,
2882                       *this, RegResults);
2883   } else {
2884     llvm::CallInst *Result =
2885         Builder.CreateCall(IA, Args, getBundlesForFunclet(IA));
2886     UpdateAsmCallInst(*Result, HasSideEffect, false, ReadOnly, ReadNone,
2887                       InNoMergeAttributedStmt, S, ResultRegTypes, ArgElemTypes,
2888                       *this, RegResults);
2889   }
2890 
2891   EmitAsmStores(*this, S, RegResults, ResultRegTypes, ResultTruncRegTypes,
2892                 ResultRegDests, ResultRegQualTys, ResultTypeRequiresCast,
2893                 ResultRegIsFlagReg);
2894 
2895   // If this is an asm goto with outputs, repeat EmitAsmStores, but with a
2896   // different insertion point; one for each indirect destination and with
2897   // CBRRegResults rather than RegResults.
2898   if (IsGCCAsmGoto && !CBRRegResults.empty()) {
2899     for (llvm::BasicBlock *Succ : CBR->getIndirectDests()) {
2900       llvm::IRBuilderBase::InsertPointGuard IPG(Builder);
2901       Builder.SetInsertPoint(Succ, --(Succ->end()));
2902       EmitAsmStores(*this, S, CBRRegResults[Succ], ResultRegTypes,
2903                     ResultTruncRegTypes, ResultRegDests, ResultRegQualTys,
2904                     ResultTypeRequiresCast, ResultRegIsFlagReg);
2905     }
2906   }
2907 }
2908 
2909 LValue CodeGenFunction::InitCapturedStruct(const CapturedStmt &S) {
2910   const RecordDecl *RD = S.getCapturedRecordDecl();
2911   QualType RecordTy = getContext().getRecordType(RD);
2912 
2913   // Initialize the captured struct.
2914   LValue SlotLV =
2915     MakeAddrLValue(CreateMemTemp(RecordTy, "agg.captured"), RecordTy);
2916 
2917   RecordDecl::field_iterator CurField = RD->field_begin();
2918   for (CapturedStmt::const_capture_init_iterator I = S.capture_init_begin(),
2919                                                  E = S.capture_init_end();
2920        I != E; ++I, ++CurField) {
2921     LValue LV = EmitLValueForFieldInitialization(SlotLV, *CurField);
2922     if (CurField->hasCapturedVLAType()) {
2923       EmitLambdaVLACapture(CurField->getCapturedVLAType(), LV);
2924     } else {
2925       EmitInitializerForField(*CurField, LV, *I);
2926     }
2927   }
2928 
2929   return SlotLV;
2930 }
2931 
2932 /// Generate an outlined function for the body of a CapturedStmt, store any
2933 /// captured variables into the captured struct, and call the outlined function.
2934 llvm::Function *
2935 CodeGenFunction::EmitCapturedStmt(const CapturedStmt &S, CapturedRegionKind K) {
2936   LValue CapStruct = InitCapturedStruct(S);
2937 
2938   // Emit the CapturedDecl
2939   CodeGenFunction CGF(CGM, true);
2940   CGCapturedStmtRAII CapInfoRAII(CGF, new CGCapturedStmtInfo(S, K));
2941   llvm::Function *F = CGF.GenerateCapturedStmtFunction(S);
2942   delete CGF.CapturedStmtInfo;
2943 
2944   // Emit call to the helper function.
2945   EmitCallOrInvoke(F, CapStruct.getPointer(*this));
2946 
2947   return F;
2948 }
2949 
2950 Address CodeGenFunction::GenerateCapturedStmtArgument(const CapturedStmt &S) {
2951   LValue CapStruct = InitCapturedStruct(S);
2952   return CapStruct.getAddress(*this);
2953 }
2954 
2955 /// Creates the outlined function for a CapturedStmt.
2956 llvm::Function *
2957 CodeGenFunction::GenerateCapturedStmtFunction(const CapturedStmt &S) {
2958   assert(CapturedStmtInfo &&
2959     "CapturedStmtInfo should be set when generating the captured function");
2960   const CapturedDecl *CD = S.getCapturedDecl();
2961   const RecordDecl *RD = S.getCapturedRecordDecl();
2962   SourceLocation Loc = S.getBeginLoc();
2963   assert(CD->hasBody() && "missing CapturedDecl body");
2964 
2965   // Build the argument list.
2966   ASTContext &Ctx = CGM.getContext();
2967   FunctionArgList Args;
2968   Args.append(CD->param_begin(), CD->param_end());
2969 
2970   // Create the function declaration.
2971   const CGFunctionInfo &FuncInfo =
2972     CGM.getTypes().arrangeBuiltinFunctionDeclaration(Ctx.VoidTy, Args);
2973   llvm::FunctionType *FuncLLVMTy = CGM.getTypes().GetFunctionType(FuncInfo);
2974 
2975   llvm::Function *F =
2976     llvm::Function::Create(FuncLLVMTy, llvm::GlobalValue::InternalLinkage,
2977                            CapturedStmtInfo->getHelperName(), &CGM.getModule());
2978   CGM.SetInternalFunctionAttributes(CD, F, FuncInfo);
2979   if (CD->isNothrow())
2980     F->addFnAttr(llvm::Attribute::NoUnwind);
2981 
2982   // Generate the function.
2983   StartFunction(CD, Ctx.VoidTy, F, FuncInfo, Args, CD->getLocation(),
2984                 CD->getBody()->getBeginLoc());
2985   // Set the context parameter in CapturedStmtInfo.
2986   Address DeclPtr = GetAddrOfLocalVar(CD->getContextParam());
2987   CapturedStmtInfo->setContextValue(Builder.CreateLoad(DeclPtr));
2988 
2989   // Initialize variable-length arrays.
2990   LValue Base = MakeNaturalAlignAddrLValue(CapturedStmtInfo->getContextValue(),
2991                                            Ctx.getTagDeclType(RD));
2992   for (auto *FD : RD->fields()) {
2993     if (FD->hasCapturedVLAType()) {
2994       auto *ExprArg =
2995           EmitLoadOfLValue(EmitLValueForField(Base, FD), S.getBeginLoc())
2996               .getScalarVal();
2997       auto VAT = FD->getCapturedVLAType();
2998       VLASizeMap[VAT->getSizeExpr()] = ExprArg;
2999     }
3000   }
3001 
3002   // If 'this' is captured, load it into CXXThisValue.
3003   if (CapturedStmtInfo->isCXXThisExprCaptured()) {
3004     FieldDecl *FD = CapturedStmtInfo->getThisFieldDecl();
3005     LValue ThisLValue = EmitLValueForField(Base, FD);
3006     CXXThisValue = EmitLoadOfLValue(ThisLValue, Loc).getScalarVal();
3007   }
3008 
3009   PGO.assignRegionCounters(GlobalDecl(CD), F);
3010   CapturedStmtInfo->EmitBody(*this, CD->getBody());
3011   FinishFunction(CD->getBodyRBrace());
3012 
3013   return F;
3014 }
3015