1 //===--- CGStmt.cpp - Emit LLVM Code from Statements ----------------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // This contains code to emit Stmt nodes as LLVM code.
10 //
11 //===----------------------------------------------------------------------===//
12 
13 #include "CGDebugInfo.h"
14 #include "CGOpenMPRuntime.h"
15 #include "CodeGenFunction.h"
16 #include "CodeGenModule.h"
17 #include "TargetInfo.h"
18 #include "clang/AST/Attr.h"
19 #include "clang/AST/Expr.h"
20 #include "clang/AST/Stmt.h"
21 #include "clang/AST/StmtVisitor.h"
22 #include "clang/Basic/Builtins.h"
23 #include "clang/Basic/DiagnosticSema.h"
24 #include "clang/Basic/PrettyStackTrace.h"
25 #include "clang/Basic/SourceManager.h"
26 #include "clang/Basic/TargetInfo.h"
27 #include "llvm/ADT/SmallSet.h"
28 #include "llvm/ADT/StringExtras.h"
29 #include "llvm/IR/DataLayout.h"
30 #include "llvm/IR/InlineAsm.h"
31 #include "llvm/IR/Intrinsics.h"
32 #include "llvm/IR/MDBuilder.h"
33 #include "llvm/Support/SaveAndRestore.h"
34 
35 using namespace clang;
36 using namespace CodeGen;
37 
38 //===----------------------------------------------------------------------===//
39 //                              Statement Emission
40 //===----------------------------------------------------------------------===//
41 
EmitStopPoint(const Stmt * S)42 void CodeGenFunction::EmitStopPoint(const Stmt *S) {
43   if (CGDebugInfo *DI = getDebugInfo()) {
44     SourceLocation Loc;
45     Loc = S->getBeginLoc();
46     DI->EmitLocation(Builder, Loc);
47 
48     LastStopPoint = Loc;
49   }
50 }
51 
EmitStmt(const Stmt * S,ArrayRef<const Attr * > Attrs)52 void CodeGenFunction::EmitStmt(const Stmt *S, ArrayRef<const Attr *> Attrs) {
53   assert(S && "Null statement?");
54   PGO.setCurrentStmt(S);
55 
56   // These statements have their own debug info handling.
57   if (EmitSimpleStmt(S, Attrs))
58     return;
59 
60   // Check if we are generating unreachable code.
61   if (!HaveInsertPoint()) {
62     // If so, and the statement doesn't contain a label, then we do not need to
63     // generate actual code. This is safe because (1) the current point is
64     // unreachable, so we don't need to execute the code, and (2) we've already
65     // handled the statements which update internal data structures (like the
66     // local variable map) which could be used by subsequent statements.
67     if (!ContainsLabel(S)) {
68       // Verify that any decl statements were handled as simple, they may be in
69       // scope of subsequent reachable statements.
70       assert(!isa<DeclStmt>(*S) && "Unexpected DeclStmt!");
71       return;
72     }
73 
74     // Otherwise, make a new block to hold the code.
75     EnsureInsertPoint();
76   }
77 
78   // Generate a stoppoint if we are emitting debug info.
79   EmitStopPoint(S);
80 
81   // Ignore all OpenMP directives except for simd if OpenMP with Simd is
82   // enabled.
83   if (getLangOpts().OpenMP && getLangOpts().OpenMPSimd) {
84     if (const auto *D = dyn_cast<OMPExecutableDirective>(S)) {
85       EmitSimpleOMPExecutableDirective(*D);
86       return;
87     }
88   }
89 
90   switch (S->getStmtClass()) {
91   case Stmt::NoStmtClass:
92   case Stmt::CXXCatchStmtClass:
93   case Stmt::SEHExceptStmtClass:
94   case Stmt::SEHFinallyStmtClass:
95   case Stmt::MSDependentExistsStmtClass:
96     llvm_unreachable("invalid statement class to emit generically");
97   case Stmt::NullStmtClass:
98   case Stmt::CompoundStmtClass:
99   case Stmt::DeclStmtClass:
100   case Stmt::LabelStmtClass:
101   case Stmt::AttributedStmtClass:
102   case Stmt::GotoStmtClass:
103   case Stmt::BreakStmtClass:
104   case Stmt::ContinueStmtClass:
105   case Stmt::DefaultStmtClass:
106   case Stmt::CaseStmtClass:
107   case Stmt::SEHLeaveStmtClass:
108     llvm_unreachable("should have emitted these statements as simple");
109 
110 #define STMT(Type, Base)
111 #define ABSTRACT_STMT(Op)
112 #define EXPR(Type, Base) \
113   case Stmt::Type##Class:
114 #include "clang/AST/StmtNodes.inc"
115   {
116     // Remember the block we came in on.
117     llvm::BasicBlock *incoming = Builder.GetInsertBlock();
118     assert(incoming && "expression emission must have an insertion point");
119 
120     EmitIgnoredExpr(cast<Expr>(S));
121 
122     llvm::BasicBlock *outgoing = Builder.GetInsertBlock();
123     assert(outgoing && "expression emission cleared block!");
124 
125     // The expression emitters assume (reasonably!) that the insertion
126     // point is always set.  To maintain that, the call-emission code
127     // for noreturn functions has to enter a new block with no
128     // predecessors.  We want to kill that block and mark the current
129     // insertion point unreachable in the common case of a call like
130     // "exit();".  Since expression emission doesn't otherwise create
131     // blocks with no predecessors, we can just test for that.
132     // However, we must be careful not to do this to our incoming
133     // block, because *statement* emission does sometimes create
134     // reachable blocks which will have no predecessors until later in
135     // the function.  This occurs with, e.g., labels that are not
136     // reachable by fallthrough.
137     if (incoming != outgoing && outgoing->use_empty()) {
138       outgoing->eraseFromParent();
139       Builder.ClearInsertionPoint();
140     }
141     break;
142   }
143 
144   case Stmt::IndirectGotoStmtClass:
145     EmitIndirectGotoStmt(cast<IndirectGotoStmt>(*S)); break;
146 
147   case Stmt::IfStmtClass:      EmitIfStmt(cast<IfStmt>(*S));              break;
148   case Stmt::WhileStmtClass:   EmitWhileStmt(cast<WhileStmt>(*S), Attrs); break;
149   case Stmt::DoStmtClass:      EmitDoStmt(cast<DoStmt>(*S), Attrs);       break;
150   case Stmt::ForStmtClass:     EmitForStmt(cast<ForStmt>(*S), Attrs);     break;
151 
152   case Stmt::ReturnStmtClass:  EmitReturnStmt(cast<ReturnStmt>(*S));      break;
153 
154   case Stmt::SwitchStmtClass:  EmitSwitchStmt(cast<SwitchStmt>(*S));      break;
155   case Stmt::GCCAsmStmtClass:  // Intentional fall-through.
156   case Stmt::MSAsmStmtClass:   EmitAsmStmt(cast<AsmStmt>(*S));            break;
157   case Stmt::CoroutineBodyStmtClass:
158     EmitCoroutineBody(cast<CoroutineBodyStmt>(*S));
159     break;
160   case Stmt::CoreturnStmtClass:
161     EmitCoreturnStmt(cast<CoreturnStmt>(*S));
162     break;
163   case Stmt::CapturedStmtClass: {
164     const CapturedStmt *CS = cast<CapturedStmt>(S);
165     EmitCapturedStmt(*CS, CS->getCapturedRegionKind());
166     }
167     break;
168   case Stmt::ObjCAtTryStmtClass:
169     EmitObjCAtTryStmt(cast<ObjCAtTryStmt>(*S));
170     break;
171   case Stmt::ObjCAtCatchStmtClass:
172     llvm_unreachable(
173                     "@catch statements should be handled by EmitObjCAtTryStmt");
174   case Stmt::ObjCAtFinallyStmtClass:
175     llvm_unreachable(
176                   "@finally statements should be handled by EmitObjCAtTryStmt");
177   case Stmt::ObjCAtThrowStmtClass:
178     EmitObjCAtThrowStmt(cast<ObjCAtThrowStmt>(*S));
179     break;
180   case Stmt::ObjCAtSynchronizedStmtClass:
181     EmitObjCAtSynchronizedStmt(cast<ObjCAtSynchronizedStmt>(*S));
182     break;
183   case Stmt::ObjCForCollectionStmtClass:
184     EmitObjCForCollectionStmt(cast<ObjCForCollectionStmt>(*S));
185     break;
186   case Stmt::ObjCAutoreleasePoolStmtClass:
187     EmitObjCAutoreleasePoolStmt(cast<ObjCAutoreleasePoolStmt>(*S));
188     break;
189 
190   case Stmt::CXXTryStmtClass:
191     EmitCXXTryStmt(cast<CXXTryStmt>(*S));
192     break;
193   case Stmt::CXXForRangeStmtClass:
194     EmitCXXForRangeStmt(cast<CXXForRangeStmt>(*S), Attrs);
195     break;
196   case Stmt::SEHTryStmtClass:
197     EmitSEHTryStmt(cast<SEHTryStmt>(*S));
198     break;
199   case Stmt::OMPCanonicalLoopClass:
200     EmitOMPCanonicalLoop(cast<OMPCanonicalLoop>(S));
201     break;
202   case Stmt::OMPParallelDirectiveClass:
203     EmitOMPParallelDirective(cast<OMPParallelDirective>(*S));
204     break;
205   case Stmt::OMPSimdDirectiveClass:
206     EmitOMPSimdDirective(cast<OMPSimdDirective>(*S));
207     break;
208   case Stmt::OMPTileDirectiveClass:
209     EmitOMPTileDirective(cast<OMPTileDirective>(*S));
210     break;
211   case Stmt::OMPUnrollDirectiveClass:
212     EmitOMPUnrollDirective(cast<OMPUnrollDirective>(*S));
213     break;
214   case Stmt::OMPForDirectiveClass:
215     EmitOMPForDirective(cast<OMPForDirective>(*S));
216     break;
217   case Stmt::OMPForSimdDirectiveClass:
218     EmitOMPForSimdDirective(cast<OMPForSimdDirective>(*S));
219     break;
220   case Stmt::OMPSectionsDirectiveClass:
221     EmitOMPSectionsDirective(cast<OMPSectionsDirective>(*S));
222     break;
223   case Stmt::OMPSectionDirectiveClass:
224     EmitOMPSectionDirective(cast<OMPSectionDirective>(*S));
225     break;
226   case Stmt::OMPSingleDirectiveClass:
227     EmitOMPSingleDirective(cast<OMPSingleDirective>(*S));
228     break;
229   case Stmt::OMPMasterDirectiveClass:
230     EmitOMPMasterDirective(cast<OMPMasterDirective>(*S));
231     break;
232   case Stmt::OMPCriticalDirectiveClass:
233     EmitOMPCriticalDirective(cast<OMPCriticalDirective>(*S));
234     break;
235   case Stmt::OMPParallelForDirectiveClass:
236     EmitOMPParallelForDirective(cast<OMPParallelForDirective>(*S));
237     break;
238   case Stmt::OMPParallelForSimdDirectiveClass:
239     EmitOMPParallelForSimdDirective(cast<OMPParallelForSimdDirective>(*S));
240     break;
241   case Stmt::OMPParallelMasterDirectiveClass:
242     EmitOMPParallelMasterDirective(cast<OMPParallelMasterDirective>(*S));
243     break;
244   case Stmt::OMPParallelSectionsDirectiveClass:
245     EmitOMPParallelSectionsDirective(cast<OMPParallelSectionsDirective>(*S));
246     break;
247   case Stmt::OMPTaskDirectiveClass:
248     EmitOMPTaskDirective(cast<OMPTaskDirective>(*S));
249     break;
250   case Stmt::OMPTaskyieldDirectiveClass:
251     EmitOMPTaskyieldDirective(cast<OMPTaskyieldDirective>(*S));
252     break;
253   case Stmt::OMPBarrierDirectiveClass:
254     EmitOMPBarrierDirective(cast<OMPBarrierDirective>(*S));
255     break;
256   case Stmt::OMPTaskwaitDirectiveClass:
257     EmitOMPTaskwaitDirective(cast<OMPTaskwaitDirective>(*S));
258     break;
259   case Stmt::OMPTaskgroupDirectiveClass:
260     EmitOMPTaskgroupDirective(cast<OMPTaskgroupDirective>(*S));
261     break;
262   case Stmt::OMPFlushDirectiveClass:
263     EmitOMPFlushDirective(cast<OMPFlushDirective>(*S));
264     break;
265   case Stmt::OMPDepobjDirectiveClass:
266     EmitOMPDepobjDirective(cast<OMPDepobjDirective>(*S));
267     break;
268   case Stmt::OMPScanDirectiveClass:
269     EmitOMPScanDirective(cast<OMPScanDirective>(*S));
270     break;
271   case Stmt::OMPOrderedDirectiveClass:
272     EmitOMPOrderedDirective(cast<OMPOrderedDirective>(*S));
273     break;
274   case Stmt::OMPAtomicDirectiveClass:
275     EmitOMPAtomicDirective(cast<OMPAtomicDirective>(*S));
276     break;
277   case Stmt::OMPTargetDirectiveClass:
278     EmitOMPTargetDirective(cast<OMPTargetDirective>(*S));
279     break;
280   case Stmt::OMPTeamsDirectiveClass:
281     EmitOMPTeamsDirective(cast<OMPTeamsDirective>(*S));
282     break;
283   case Stmt::OMPCancellationPointDirectiveClass:
284     EmitOMPCancellationPointDirective(cast<OMPCancellationPointDirective>(*S));
285     break;
286   case Stmt::OMPCancelDirectiveClass:
287     EmitOMPCancelDirective(cast<OMPCancelDirective>(*S));
288     break;
289   case Stmt::OMPTargetDataDirectiveClass:
290     EmitOMPTargetDataDirective(cast<OMPTargetDataDirective>(*S));
291     break;
292   case Stmt::OMPTargetEnterDataDirectiveClass:
293     EmitOMPTargetEnterDataDirective(cast<OMPTargetEnterDataDirective>(*S));
294     break;
295   case Stmt::OMPTargetExitDataDirectiveClass:
296     EmitOMPTargetExitDataDirective(cast<OMPTargetExitDataDirective>(*S));
297     break;
298   case Stmt::OMPTargetParallelDirectiveClass:
299     EmitOMPTargetParallelDirective(cast<OMPTargetParallelDirective>(*S));
300     break;
301   case Stmt::OMPTargetParallelForDirectiveClass:
302     EmitOMPTargetParallelForDirective(cast<OMPTargetParallelForDirective>(*S));
303     break;
304   case Stmt::OMPTaskLoopDirectiveClass:
305     EmitOMPTaskLoopDirective(cast<OMPTaskLoopDirective>(*S));
306     break;
307   case Stmt::OMPTaskLoopSimdDirectiveClass:
308     EmitOMPTaskLoopSimdDirective(cast<OMPTaskLoopSimdDirective>(*S));
309     break;
310   case Stmt::OMPMasterTaskLoopDirectiveClass:
311     EmitOMPMasterTaskLoopDirective(cast<OMPMasterTaskLoopDirective>(*S));
312     break;
313   case Stmt::OMPMasterTaskLoopSimdDirectiveClass:
314     EmitOMPMasterTaskLoopSimdDirective(
315         cast<OMPMasterTaskLoopSimdDirective>(*S));
316     break;
317   case Stmt::OMPParallelMasterTaskLoopDirectiveClass:
318     EmitOMPParallelMasterTaskLoopDirective(
319         cast<OMPParallelMasterTaskLoopDirective>(*S));
320     break;
321   case Stmt::OMPParallelMasterTaskLoopSimdDirectiveClass:
322     EmitOMPParallelMasterTaskLoopSimdDirective(
323         cast<OMPParallelMasterTaskLoopSimdDirective>(*S));
324     break;
325   case Stmt::OMPDistributeDirectiveClass:
326     EmitOMPDistributeDirective(cast<OMPDistributeDirective>(*S));
327     break;
328   case Stmt::OMPTargetUpdateDirectiveClass:
329     EmitOMPTargetUpdateDirective(cast<OMPTargetUpdateDirective>(*S));
330     break;
331   case Stmt::OMPDistributeParallelForDirectiveClass:
332     EmitOMPDistributeParallelForDirective(
333         cast<OMPDistributeParallelForDirective>(*S));
334     break;
335   case Stmt::OMPDistributeParallelForSimdDirectiveClass:
336     EmitOMPDistributeParallelForSimdDirective(
337         cast<OMPDistributeParallelForSimdDirective>(*S));
338     break;
339   case Stmt::OMPDistributeSimdDirectiveClass:
340     EmitOMPDistributeSimdDirective(cast<OMPDistributeSimdDirective>(*S));
341     break;
342   case Stmt::OMPTargetParallelForSimdDirectiveClass:
343     EmitOMPTargetParallelForSimdDirective(
344         cast<OMPTargetParallelForSimdDirective>(*S));
345     break;
346   case Stmt::OMPTargetSimdDirectiveClass:
347     EmitOMPTargetSimdDirective(cast<OMPTargetSimdDirective>(*S));
348     break;
349   case Stmt::OMPTeamsDistributeDirectiveClass:
350     EmitOMPTeamsDistributeDirective(cast<OMPTeamsDistributeDirective>(*S));
351     break;
352   case Stmt::OMPTeamsDistributeSimdDirectiveClass:
353     EmitOMPTeamsDistributeSimdDirective(
354         cast<OMPTeamsDistributeSimdDirective>(*S));
355     break;
356   case Stmt::OMPTeamsDistributeParallelForSimdDirectiveClass:
357     EmitOMPTeamsDistributeParallelForSimdDirective(
358         cast<OMPTeamsDistributeParallelForSimdDirective>(*S));
359     break;
360   case Stmt::OMPTeamsDistributeParallelForDirectiveClass:
361     EmitOMPTeamsDistributeParallelForDirective(
362         cast<OMPTeamsDistributeParallelForDirective>(*S));
363     break;
364   case Stmt::OMPTargetTeamsDirectiveClass:
365     EmitOMPTargetTeamsDirective(cast<OMPTargetTeamsDirective>(*S));
366     break;
367   case Stmt::OMPTargetTeamsDistributeDirectiveClass:
368     EmitOMPTargetTeamsDistributeDirective(
369         cast<OMPTargetTeamsDistributeDirective>(*S));
370     break;
371   case Stmt::OMPTargetTeamsDistributeParallelForDirectiveClass:
372     EmitOMPTargetTeamsDistributeParallelForDirective(
373         cast<OMPTargetTeamsDistributeParallelForDirective>(*S));
374     break;
375   case Stmt::OMPTargetTeamsDistributeParallelForSimdDirectiveClass:
376     EmitOMPTargetTeamsDistributeParallelForSimdDirective(
377         cast<OMPTargetTeamsDistributeParallelForSimdDirective>(*S));
378     break;
379   case Stmt::OMPTargetTeamsDistributeSimdDirectiveClass:
380     EmitOMPTargetTeamsDistributeSimdDirective(
381         cast<OMPTargetTeamsDistributeSimdDirective>(*S));
382     break;
383   case Stmt::OMPInteropDirectiveClass:
384     llvm_unreachable("Interop directive not supported yet.");
385     break;
386   case Stmt::OMPDispatchDirectiveClass:
387     llvm_unreachable("Dispatch directive not supported yet.");
388     break;
389   case Stmt::OMPMaskedDirectiveClass:
390     EmitOMPMaskedDirective(cast<OMPMaskedDirective>(*S));
391     break;
392   }
393 }
394 
EmitSimpleStmt(const Stmt * S,ArrayRef<const Attr * > Attrs)395 bool CodeGenFunction::EmitSimpleStmt(const Stmt *S,
396                                      ArrayRef<const Attr *> Attrs) {
397   switch (S->getStmtClass()) {
398   default:
399     return false;
400   case Stmt::NullStmtClass:
401     break;
402   case Stmt::CompoundStmtClass:
403     EmitCompoundStmt(cast<CompoundStmt>(*S));
404     break;
405   case Stmt::DeclStmtClass:
406     EmitDeclStmt(cast<DeclStmt>(*S));
407     break;
408   case Stmt::LabelStmtClass:
409     EmitLabelStmt(cast<LabelStmt>(*S));
410     break;
411   case Stmt::AttributedStmtClass:
412     EmitAttributedStmt(cast<AttributedStmt>(*S));
413     break;
414   case Stmt::GotoStmtClass:
415     EmitGotoStmt(cast<GotoStmt>(*S));
416     break;
417   case Stmt::BreakStmtClass:
418     EmitBreakStmt(cast<BreakStmt>(*S));
419     break;
420   case Stmt::ContinueStmtClass:
421     EmitContinueStmt(cast<ContinueStmt>(*S));
422     break;
423   case Stmt::DefaultStmtClass:
424     EmitDefaultStmt(cast<DefaultStmt>(*S), Attrs);
425     break;
426   case Stmt::CaseStmtClass:
427     EmitCaseStmt(cast<CaseStmt>(*S), Attrs);
428     break;
429   case Stmt::SEHLeaveStmtClass:
430     EmitSEHLeaveStmt(cast<SEHLeaveStmt>(*S));
431     break;
432   }
433   return true;
434 }
435 
436 /// EmitCompoundStmt - Emit a compound statement {..} node.  If GetLast is true,
437 /// this captures the expression result of the last sub-statement and returns it
438 /// (for use by the statement expression extension).
EmitCompoundStmt(const CompoundStmt & S,bool GetLast,AggValueSlot AggSlot)439 Address CodeGenFunction::EmitCompoundStmt(const CompoundStmt &S, bool GetLast,
440                                           AggValueSlot AggSlot) {
441   PrettyStackTraceLoc CrashInfo(getContext().getSourceManager(),S.getLBracLoc(),
442                              "LLVM IR generation of compound statement ('{}')");
443 
444   // Keep track of the current cleanup stack depth, including debug scopes.
445   LexicalScope Scope(*this, S.getSourceRange());
446 
447   return EmitCompoundStmtWithoutScope(S, GetLast, AggSlot);
448 }
449 
450 Address
EmitCompoundStmtWithoutScope(const CompoundStmt & S,bool GetLast,AggValueSlot AggSlot)451 CodeGenFunction::EmitCompoundStmtWithoutScope(const CompoundStmt &S,
452                                               bool GetLast,
453                                               AggValueSlot AggSlot) {
454 
455   const Stmt *ExprResult = S.getStmtExprResult();
456   assert((!GetLast || (GetLast && ExprResult)) &&
457          "If GetLast is true then the CompoundStmt must have a StmtExprResult");
458 
459   Address RetAlloca = Address::invalid();
460 
461   for (auto *CurStmt : S.body()) {
462     if (GetLast && ExprResult == CurStmt) {
463       // We have to special case labels here.  They are statements, but when put
464       // at the end of a statement expression, they yield the value of their
465       // subexpression.  Handle this by walking through all labels we encounter,
466       // emitting them before we evaluate the subexpr.
467       // Similar issues arise for attributed statements.
468       while (!isa<Expr>(ExprResult)) {
469         if (const auto *LS = dyn_cast<LabelStmt>(ExprResult)) {
470           EmitLabel(LS->getDecl());
471           ExprResult = LS->getSubStmt();
472         } else if (const auto *AS = dyn_cast<AttributedStmt>(ExprResult)) {
473           // FIXME: Update this if we ever have attributes that affect the
474           // semantics of an expression.
475           ExprResult = AS->getSubStmt();
476         } else {
477           llvm_unreachable("unknown value statement");
478         }
479       }
480 
481       EnsureInsertPoint();
482 
483       const Expr *E = cast<Expr>(ExprResult);
484       QualType ExprTy = E->getType();
485       if (hasAggregateEvaluationKind(ExprTy)) {
486         EmitAggExpr(E, AggSlot);
487       } else {
488         // We can't return an RValue here because there might be cleanups at
489         // the end of the StmtExpr.  Because of that, we have to emit the result
490         // here into a temporary alloca.
491         RetAlloca = CreateMemTemp(ExprTy);
492         EmitAnyExprToMem(E, RetAlloca, Qualifiers(),
493                          /*IsInit*/ false);
494       }
495     } else {
496       EmitStmt(CurStmt);
497     }
498   }
499 
500   return RetAlloca;
501 }
502 
SimplifyForwardingBlocks(llvm::BasicBlock * BB)503 void CodeGenFunction::SimplifyForwardingBlocks(llvm::BasicBlock *BB) {
504   llvm::BranchInst *BI = dyn_cast<llvm::BranchInst>(BB->getTerminator());
505 
506   // If there is a cleanup stack, then we it isn't worth trying to
507   // simplify this block (we would need to remove it from the scope map
508   // and cleanup entry).
509   if (!EHStack.empty())
510     return;
511 
512   // Can only simplify direct branches.
513   if (!BI || !BI->isUnconditional())
514     return;
515 
516   // Can only simplify empty blocks.
517   if (BI->getIterator() != BB->begin())
518     return;
519 
520   BB->replaceAllUsesWith(BI->getSuccessor(0));
521   BI->eraseFromParent();
522   BB->eraseFromParent();
523 }
524 
EmitBlock(llvm::BasicBlock * BB,bool IsFinished)525 void CodeGenFunction::EmitBlock(llvm::BasicBlock *BB, bool IsFinished) {
526   llvm::BasicBlock *CurBB = Builder.GetInsertBlock();
527 
528   // Fall out of the current block (if necessary).
529   EmitBranch(BB);
530 
531   if (IsFinished && BB->use_empty()) {
532     delete BB;
533     return;
534   }
535 
536   // Place the block after the current block, if possible, or else at
537   // the end of the function.
538   if (CurBB && CurBB->getParent())
539     CurFn->getBasicBlockList().insertAfter(CurBB->getIterator(), BB);
540   else
541     CurFn->getBasicBlockList().push_back(BB);
542   Builder.SetInsertPoint(BB);
543 }
544 
EmitBranch(llvm::BasicBlock * Target)545 void CodeGenFunction::EmitBranch(llvm::BasicBlock *Target) {
546   // Emit a branch from the current block to the target one if this
547   // was a real block.  If this was just a fall-through block after a
548   // terminator, don't emit it.
549   llvm::BasicBlock *CurBB = Builder.GetInsertBlock();
550 
551   if (!CurBB || CurBB->getTerminator()) {
552     // If there is no insert point or the previous block is already
553     // terminated, don't touch it.
554   } else {
555     // Otherwise, create a fall-through branch.
556     Builder.CreateBr(Target);
557   }
558 
559   Builder.ClearInsertionPoint();
560 }
561 
EmitBlockAfterUses(llvm::BasicBlock * block)562 void CodeGenFunction::EmitBlockAfterUses(llvm::BasicBlock *block) {
563   bool inserted = false;
564   for (llvm::User *u : block->users()) {
565     if (llvm::Instruction *insn = dyn_cast<llvm::Instruction>(u)) {
566       CurFn->getBasicBlockList().insertAfter(insn->getParent()->getIterator(),
567                                              block);
568       inserted = true;
569       break;
570     }
571   }
572 
573   if (!inserted)
574     CurFn->getBasicBlockList().push_back(block);
575 
576   Builder.SetInsertPoint(block);
577 }
578 
579 CodeGenFunction::JumpDest
getJumpDestForLabel(const LabelDecl * D)580 CodeGenFunction::getJumpDestForLabel(const LabelDecl *D) {
581   JumpDest &Dest = LabelMap[D];
582   if (Dest.isValid()) return Dest;
583 
584   // Create, but don't insert, the new block.
585   Dest = JumpDest(createBasicBlock(D->getName()),
586                   EHScopeStack::stable_iterator::invalid(),
587                   NextCleanupDestIndex++);
588   return Dest;
589 }
590 
EmitLabel(const LabelDecl * D)591 void CodeGenFunction::EmitLabel(const LabelDecl *D) {
592   // Add this label to the current lexical scope if we're within any
593   // normal cleanups.  Jumps "in" to this label --- when permitted by
594   // the language --- may need to be routed around such cleanups.
595   if (EHStack.hasNormalCleanups() && CurLexicalScope)
596     CurLexicalScope->addLabel(D);
597 
598   JumpDest &Dest = LabelMap[D];
599 
600   // If we didn't need a forward reference to this label, just go
601   // ahead and create a destination at the current scope.
602   if (!Dest.isValid()) {
603     Dest = getJumpDestInCurrentScope(D->getName());
604 
605   // Otherwise, we need to give this label a target depth and remove
606   // it from the branch-fixups list.
607   } else {
608     assert(!Dest.getScopeDepth().isValid() && "already emitted label!");
609     Dest.setScopeDepth(EHStack.stable_begin());
610     ResolveBranchFixups(Dest.getBlock());
611   }
612 
613   EmitBlock(Dest.getBlock());
614 
615   // Emit debug info for labels.
616   if (CGDebugInfo *DI = getDebugInfo()) {
617     if (CGM.getCodeGenOpts().hasReducedDebugInfo()) {
618       DI->setLocation(D->getLocation());
619       DI->EmitLabel(D, Builder);
620     }
621   }
622 
623   incrementProfileCounter(D->getStmt());
624 }
625 
626 /// Change the cleanup scope of the labels in this lexical scope to
627 /// match the scope of the enclosing context.
rescopeLabels()628 void CodeGenFunction::LexicalScope::rescopeLabels() {
629   assert(!Labels.empty());
630   EHScopeStack::stable_iterator innermostScope
631     = CGF.EHStack.getInnermostNormalCleanup();
632 
633   // Change the scope depth of all the labels.
634   for (SmallVectorImpl<const LabelDecl*>::const_iterator
635          i = Labels.begin(), e = Labels.end(); i != e; ++i) {
636     assert(CGF.LabelMap.count(*i));
637     JumpDest &dest = CGF.LabelMap.find(*i)->second;
638     assert(dest.getScopeDepth().isValid());
639     assert(innermostScope.encloses(dest.getScopeDepth()));
640     dest.setScopeDepth(innermostScope);
641   }
642 
643   // Reparent the labels if the new scope also has cleanups.
644   if (innermostScope != EHScopeStack::stable_end() && ParentScope) {
645     ParentScope->Labels.append(Labels.begin(), Labels.end());
646   }
647 }
648 
649 
EmitLabelStmt(const LabelStmt & S)650 void CodeGenFunction::EmitLabelStmt(const LabelStmt &S) {
651   EmitLabel(S.getDecl());
652 
653   // IsEHa - emit eha.scope.begin if it's a side entry of a scope
654   if (getLangOpts().EHAsynch && S.isSideEntry())
655     EmitSehCppScopeBegin();
656 
657   EmitStmt(S.getSubStmt());
658 }
659 
EmitAttributedStmt(const AttributedStmt & S)660 void CodeGenFunction::EmitAttributedStmt(const AttributedStmt &S) {
661   bool nomerge = false;
662   const CallExpr *musttail = nullptr;
663 
664   for (const auto *A : S.getAttrs()) {
665     if (A->getKind() == attr::NoMerge) {
666       nomerge = true;
667     }
668     if (A->getKind() == attr::MustTail) {
669       const Stmt *Sub = S.getSubStmt();
670       const ReturnStmt *R = cast<ReturnStmt>(Sub);
671       musttail = cast<CallExpr>(R->getRetValue()->IgnoreParens());
672     }
673   }
674   SaveAndRestore<bool> save_nomerge(InNoMergeAttributedStmt, nomerge);
675   SaveAndRestore<const CallExpr *> save_musttail(MustTailCall, musttail);
676   EmitStmt(S.getSubStmt(), S.getAttrs());
677 }
678 
EmitGotoStmt(const GotoStmt & S)679 void CodeGenFunction::EmitGotoStmt(const GotoStmt &S) {
680   // If this code is reachable then emit a stop point (if generating
681   // debug info). We have to do this ourselves because we are on the
682   // "simple" statement path.
683   if (HaveInsertPoint())
684     EmitStopPoint(&S);
685 
686   EmitBranchThroughCleanup(getJumpDestForLabel(S.getLabel()));
687 }
688 
689 
EmitIndirectGotoStmt(const IndirectGotoStmt & S)690 void CodeGenFunction::EmitIndirectGotoStmt(const IndirectGotoStmt &S) {
691   if (const LabelDecl *Target = S.getConstantTarget()) {
692     EmitBranchThroughCleanup(getJumpDestForLabel(Target));
693     return;
694   }
695 
696   // Ensure that we have an i8* for our PHI node.
697   llvm::Value *V = Builder.CreateBitCast(EmitScalarExpr(S.getTarget()),
698                                          Int8PtrTy, "addr");
699   llvm::BasicBlock *CurBB = Builder.GetInsertBlock();
700 
701   // Get the basic block for the indirect goto.
702   llvm::BasicBlock *IndGotoBB = GetIndirectGotoBlock();
703 
704   // The first instruction in the block has to be the PHI for the switch dest,
705   // add an entry for this branch.
706   cast<llvm::PHINode>(IndGotoBB->begin())->addIncoming(V, CurBB);
707 
708   EmitBranch(IndGotoBB);
709 }
710 
EmitIfStmt(const IfStmt & S)711 void CodeGenFunction::EmitIfStmt(const IfStmt &S) {
712   // C99 6.8.4.1: The first substatement is executed if the expression compares
713   // unequal to 0.  The condition must be a scalar type.
714   LexicalScope ConditionScope(*this, S.getCond()->getSourceRange());
715 
716   if (S.getInit())
717     EmitStmt(S.getInit());
718 
719   if (S.getConditionVariable())
720     EmitDecl(*S.getConditionVariable());
721 
722   // If the condition constant folds and can be elided, try to avoid emitting
723   // the condition and the dead arm of the if/else.
724   bool CondConstant;
725   if (ConstantFoldsToSimpleInteger(S.getCond(), CondConstant,
726                                    S.isConstexpr())) {
727     // Figure out which block (then or else) is executed.
728     const Stmt *Executed = S.getThen();
729     const Stmt *Skipped  = S.getElse();
730     if (!CondConstant)  // Condition false?
731       std::swap(Executed, Skipped);
732 
733     // If the skipped block has no labels in it, just emit the executed block.
734     // This avoids emitting dead code and simplifies the CFG substantially.
735     if (S.isConstexpr() || !ContainsLabel(Skipped)) {
736       if (CondConstant)
737         incrementProfileCounter(&S);
738       if (Executed) {
739         RunCleanupsScope ExecutedScope(*this);
740         EmitStmt(Executed);
741       }
742       return;
743     }
744   }
745 
746   // Otherwise, the condition did not fold, or we couldn't elide it.  Just emit
747   // the conditional branch.
748   llvm::BasicBlock *ThenBlock = createBasicBlock("if.then");
749   llvm::BasicBlock *ContBlock = createBasicBlock("if.end");
750   llvm::BasicBlock *ElseBlock = ContBlock;
751   if (S.getElse())
752     ElseBlock = createBasicBlock("if.else");
753 
754   // Prefer the PGO based weights over the likelihood attribute.
755   // When the build isn't optimized the metadata isn't used, so don't generate
756   // it.
757   Stmt::Likelihood LH = Stmt::LH_None;
758   uint64_t Count = getProfileCount(S.getThen());
759   if (!Count && CGM.getCodeGenOpts().OptimizationLevel)
760     LH = Stmt::getLikelihood(S.getThen(), S.getElse());
761   EmitBranchOnBoolExpr(S.getCond(), ThenBlock, ElseBlock, Count, LH);
762 
763   // Emit the 'then' code.
764   EmitBlock(ThenBlock);
765   incrementProfileCounter(&S);
766   {
767     RunCleanupsScope ThenScope(*this);
768     EmitStmt(S.getThen());
769   }
770   EmitBranch(ContBlock);
771 
772   // Emit the 'else' code if present.
773   if (const Stmt *Else = S.getElse()) {
774     {
775       // There is no need to emit line number for an unconditional branch.
776       auto NL = ApplyDebugLocation::CreateEmpty(*this);
777       EmitBlock(ElseBlock);
778     }
779     {
780       RunCleanupsScope ElseScope(*this);
781       EmitStmt(Else);
782     }
783     {
784       // There is no need to emit line number for an unconditional branch.
785       auto NL = ApplyDebugLocation::CreateEmpty(*this);
786       EmitBranch(ContBlock);
787     }
788   }
789 
790   // Emit the continuation block for code after the if.
791   EmitBlock(ContBlock, true);
792 }
793 
EmitWhileStmt(const WhileStmt & S,ArrayRef<const Attr * > WhileAttrs)794 void CodeGenFunction::EmitWhileStmt(const WhileStmt &S,
795                                     ArrayRef<const Attr *> WhileAttrs) {
796   // Emit the header for the loop, which will also become
797   // the continue target.
798   JumpDest LoopHeader = getJumpDestInCurrentScope("while.cond");
799   EmitBlock(LoopHeader.getBlock());
800 
801   // Create an exit block for when the condition fails, which will
802   // also become the break target.
803   JumpDest LoopExit = getJumpDestInCurrentScope("while.end");
804 
805   // Store the blocks to use for break and continue.
806   BreakContinueStack.push_back(BreakContinue(LoopExit, LoopHeader));
807 
808   // C++ [stmt.while]p2:
809   //   When the condition of a while statement is a declaration, the
810   //   scope of the variable that is declared extends from its point
811   //   of declaration (3.3.2) to the end of the while statement.
812   //   [...]
813   //   The object created in a condition is destroyed and created
814   //   with each iteration of the loop.
815   RunCleanupsScope ConditionScope(*this);
816 
817   if (S.getConditionVariable())
818     EmitDecl(*S.getConditionVariable());
819 
820   // Evaluate the conditional in the while header.  C99 6.8.5.1: The
821   // evaluation of the controlling expression takes place before each
822   // execution of the loop body.
823   llvm::Value *BoolCondVal = EvaluateExprAsBool(S.getCond());
824 
825   // while(1) is common, avoid extra exit blocks.  Be sure
826   // to correctly handle break/continue though.
827   llvm::ConstantInt *C = dyn_cast<llvm::ConstantInt>(BoolCondVal);
828   bool CondIsConstInt = C != nullptr;
829   bool EmitBoolCondBranch = !CondIsConstInt || !C->isOne();
830   const SourceRange &R = S.getSourceRange();
831   LoopStack.push(LoopHeader.getBlock(), CGM.getContext(), CGM.getCodeGenOpts(),
832                  WhileAttrs, SourceLocToDebugLoc(R.getBegin()),
833                  SourceLocToDebugLoc(R.getEnd()),
834                  checkIfLoopMustProgress(CondIsConstInt));
835 
836   // As long as the condition is true, go to the loop body.
837   llvm::BasicBlock *LoopBody = createBasicBlock("while.body");
838   if (EmitBoolCondBranch) {
839     llvm::BasicBlock *ExitBlock = LoopExit.getBlock();
840     if (ConditionScope.requiresCleanups())
841       ExitBlock = createBasicBlock("while.exit");
842     llvm::MDNode *Weights =
843         createProfileWeightsForLoop(S.getCond(), getProfileCount(S.getBody()));
844     if (!Weights && CGM.getCodeGenOpts().OptimizationLevel)
845       BoolCondVal = emitCondLikelihoodViaExpectIntrinsic(
846           BoolCondVal, Stmt::getLikelihood(S.getBody()));
847     Builder.CreateCondBr(BoolCondVal, LoopBody, ExitBlock, Weights);
848 
849     if (ExitBlock != LoopExit.getBlock()) {
850       EmitBlock(ExitBlock);
851       EmitBranchThroughCleanup(LoopExit);
852     }
853   } else if (const Attr *A = Stmt::getLikelihoodAttr(S.getBody())) {
854     CGM.getDiags().Report(A->getLocation(),
855                           diag::warn_attribute_has_no_effect_on_infinite_loop)
856         << A << A->getRange();
857     CGM.getDiags().Report(
858         S.getWhileLoc(),
859         diag::note_attribute_has_no_effect_on_infinite_loop_here)
860         << SourceRange(S.getWhileLoc(), S.getRParenLoc());
861   }
862 
863   // Emit the loop body.  We have to emit this in a cleanup scope
864   // because it might be a singleton DeclStmt.
865   {
866     RunCleanupsScope BodyScope(*this);
867     EmitBlock(LoopBody);
868     incrementProfileCounter(&S);
869     EmitStmt(S.getBody());
870   }
871 
872   BreakContinueStack.pop_back();
873 
874   // Immediately force cleanup.
875   ConditionScope.ForceCleanup();
876 
877   EmitStopPoint(&S);
878   // Branch to the loop header again.
879   EmitBranch(LoopHeader.getBlock());
880 
881   LoopStack.pop();
882 
883   // Emit the exit block.
884   EmitBlock(LoopExit.getBlock(), true);
885 
886   // The LoopHeader typically is just a branch if we skipped emitting
887   // a branch, try to erase it.
888   if (!EmitBoolCondBranch)
889     SimplifyForwardingBlocks(LoopHeader.getBlock());
890 }
891 
EmitDoStmt(const DoStmt & S,ArrayRef<const Attr * > DoAttrs)892 void CodeGenFunction::EmitDoStmt(const DoStmt &S,
893                                  ArrayRef<const Attr *> DoAttrs) {
894   JumpDest LoopExit = getJumpDestInCurrentScope("do.end");
895   JumpDest LoopCond = getJumpDestInCurrentScope("do.cond");
896 
897   uint64_t ParentCount = getCurrentProfileCount();
898 
899   // Store the blocks to use for break and continue.
900   BreakContinueStack.push_back(BreakContinue(LoopExit, LoopCond));
901 
902   // Emit the body of the loop.
903   llvm::BasicBlock *LoopBody = createBasicBlock("do.body");
904 
905   EmitBlockWithFallThrough(LoopBody, &S);
906   {
907     RunCleanupsScope BodyScope(*this);
908     EmitStmt(S.getBody());
909   }
910 
911   EmitBlock(LoopCond.getBlock());
912 
913   // C99 6.8.5.2: "The evaluation of the controlling expression takes place
914   // after each execution of the loop body."
915 
916   // Evaluate the conditional in the while header.
917   // C99 6.8.5p2/p4: The first substatement is executed if the expression
918   // compares unequal to 0.  The condition must be a scalar type.
919   llvm::Value *BoolCondVal = EvaluateExprAsBool(S.getCond());
920 
921   BreakContinueStack.pop_back();
922 
923   // "do {} while (0)" is common in macros, avoid extra blocks.  Be sure
924   // to correctly handle break/continue though.
925   llvm::ConstantInt *C = dyn_cast<llvm::ConstantInt>(BoolCondVal);
926   bool CondIsConstInt = C;
927   bool EmitBoolCondBranch = !C || !C->isZero();
928 
929   const SourceRange &R = S.getSourceRange();
930   LoopStack.push(LoopBody, CGM.getContext(), CGM.getCodeGenOpts(), DoAttrs,
931                  SourceLocToDebugLoc(R.getBegin()),
932                  SourceLocToDebugLoc(R.getEnd()),
933                  checkIfLoopMustProgress(CondIsConstInt));
934 
935   // As long as the condition is true, iterate the loop.
936   if (EmitBoolCondBranch) {
937     uint64_t BackedgeCount = getProfileCount(S.getBody()) - ParentCount;
938     Builder.CreateCondBr(
939         BoolCondVal, LoopBody, LoopExit.getBlock(),
940         createProfileWeightsForLoop(S.getCond(), BackedgeCount));
941   }
942 
943   LoopStack.pop();
944 
945   // Emit the exit block.
946   EmitBlock(LoopExit.getBlock());
947 
948   // The DoCond block typically is just a branch if we skipped
949   // emitting a branch, try to erase it.
950   if (!EmitBoolCondBranch)
951     SimplifyForwardingBlocks(LoopCond.getBlock());
952 }
953 
EmitForStmt(const ForStmt & S,ArrayRef<const Attr * > ForAttrs)954 void CodeGenFunction::EmitForStmt(const ForStmt &S,
955                                   ArrayRef<const Attr *> ForAttrs) {
956   JumpDest LoopExit = getJumpDestInCurrentScope("for.end");
957 
958   LexicalScope ForScope(*this, S.getSourceRange());
959 
960   // Evaluate the first part before the loop.
961   if (S.getInit())
962     EmitStmt(S.getInit());
963 
964   // Start the loop with a block that tests the condition.
965   // If there's an increment, the continue scope will be overwritten
966   // later.
967   JumpDest CondDest = getJumpDestInCurrentScope("for.cond");
968   llvm::BasicBlock *CondBlock = CondDest.getBlock();
969   EmitBlock(CondBlock);
970 
971   Expr::EvalResult Result;
972   bool CondIsConstInt =
973       !S.getCond() || S.getCond()->EvaluateAsInt(Result, getContext());
974 
975   const SourceRange &R = S.getSourceRange();
976   LoopStack.push(CondBlock, CGM.getContext(), CGM.getCodeGenOpts(), ForAttrs,
977                  SourceLocToDebugLoc(R.getBegin()),
978                  SourceLocToDebugLoc(R.getEnd()),
979                  checkIfLoopMustProgress(CondIsConstInt));
980 
981   // Create a cleanup scope for the condition variable cleanups.
982   LexicalScope ConditionScope(*this, S.getSourceRange());
983 
984   // If the for loop doesn't have an increment we can just use the condition as
985   // the continue block. Otherwise, if there is no condition variable, we can
986   // form the continue block now. If there is a condition variable, we can't
987   // form the continue block until after we've emitted the condition, because
988   // the condition is in scope in the increment, but Sema's jump diagnostics
989   // ensure that there are no continues from the condition variable that jump
990   // to the loop increment.
991   JumpDest Continue;
992   if (!S.getInc())
993     Continue = CondDest;
994   else if (!S.getConditionVariable())
995     Continue = getJumpDestInCurrentScope("for.inc");
996   BreakContinueStack.push_back(BreakContinue(LoopExit, Continue));
997 
998   if (S.getCond()) {
999     // If the for statement has a condition scope, emit the local variable
1000     // declaration.
1001     if (S.getConditionVariable()) {
1002       EmitDecl(*S.getConditionVariable());
1003 
1004       // We have entered the condition variable's scope, so we're now able to
1005       // jump to the continue block.
1006       Continue = S.getInc() ? getJumpDestInCurrentScope("for.inc") : CondDest;
1007       BreakContinueStack.back().ContinueBlock = Continue;
1008     }
1009 
1010     llvm::BasicBlock *ExitBlock = LoopExit.getBlock();
1011     // If there are any cleanups between here and the loop-exit scope,
1012     // create a block to stage a loop exit along.
1013     if (ForScope.requiresCleanups())
1014       ExitBlock = createBasicBlock("for.cond.cleanup");
1015 
1016     // As long as the condition is true, iterate the loop.
1017     llvm::BasicBlock *ForBody = createBasicBlock("for.body");
1018 
1019     // C99 6.8.5p2/p4: The first substatement is executed if the expression
1020     // compares unequal to 0.  The condition must be a scalar type.
1021     llvm::Value *BoolCondVal = EvaluateExprAsBool(S.getCond());
1022     llvm::MDNode *Weights =
1023         createProfileWeightsForLoop(S.getCond(), getProfileCount(S.getBody()));
1024     if (!Weights && CGM.getCodeGenOpts().OptimizationLevel)
1025       BoolCondVal = emitCondLikelihoodViaExpectIntrinsic(
1026           BoolCondVal, Stmt::getLikelihood(S.getBody()));
1027 
1028     Builder.CreateCondBr(BoolCondVal, ForBody, ExitBlock, Weights);
1029 
1030     if (ExitBlock != LoopExit.getBlock()) {
1031       EmitBlock(ExitBlock);
1032       EmitBranchThroughCleanup(LoopExit);
1033     }
1034 
1035     EmitBlock(ForBody);
1036   } else {
1037     // Treat it as a non-zero constant.  Don't even create a new block for the
1038     // body, just fall into it.
1039   }
1040   incrementProfileCounter(&S);
1041 
1042   {
1043     // Create a separate cleanup scope for the body, in case it is not
1044     // a compound statement.
1045     RunCleanupsScope BodyScope(*this);
1046     EmitStmt(S.getBody());
1047   }
1048 
1049   // If there is an increment, emit it next.
1050   if (S.getInc()) {
1051     EmitBlock(Continue.getBlock());
1052     EmitStmt(S.getInc());
1053   }
1054 
1055   BreakContinueStack.pop_back();
1056 
1057   ConditionScope.ForceCleanup();
1058 
1059   EmitStopPoint(&S);
1060   EmitBranch(CondBlock);
1061 
1062   ForScope.ForceCleanup();
1063 
1064   LoopStack.pop();
1065 
1066   // Emit the fall-through block.
1067   EmitBlock(LoopExit.getBlock(), true);
1068 }
1069 
1070 void
EmitCXXForRangeStmt(const CXXForRangeStmt & S,ArrayRef<const Attr * > ForAttrs)1071 CodeGenFunction::EmitCXXForRangeStmt(const CXXForRangeStmt &S,
1072                                      ArrayRef<const Attr *> ForAttrs) {
1073   JumpDest LoopExit = getJumpDestInCurrentScope("for.end");
1074 
1075   LexicalScope ForScope(*this, S.getSourceRange());
1076 
1077   // Evaluate the first pieces before the loop.
1078   if (S.getInit())
1079     EmitStmt(S.getInit());
1080   EmitStmt(S.getRangeStmt());
1081   EmitStmt(S.getBeginStmt());
1082   EmitStmt(S.getEndStmt());
1083 
1084   // Start the loop with a block that tests the condition.
1085   // If there's an increment, the continue scope will be overwritten
1086   // later.
1087   llvm::BasicBlock *CondBlock = createBasicBlock("for.cond");
1088   EmitBlock(CondBlock);
1089 
1090   const SourceRange &R = S.getSourceRange();
1091   LoopStack.push(CondBlock, CGM.getContext(), CGM.getCodeGenOpts(), ForAttrs,
1092                  SourceLocToDebugLoc(R.getBegin()),
1093                  SourceLocToDebugLoc(R.getEnd()));
1094 
1095   // If there are any cleanups between here and the loop-exit scope,
1096   // create a block to stage a loop exit along.
1097   llvm::BasicBlock *ExitBlock = LoopExit.getBlock();
1098   if (ForScope.requiresCleanups())
1099     ExitBlock = createBasicBlock("for.cond.cleanup");
1100 
1101   // The loop body, consisting of the specified body and the loop variable.
1102   llvm::BasicBlock *ForBody = createBasicBlock("for.body");
1103 
1104   // The body is executed if the expression, contextually converted
1105   // to bool, is true.
1106   llvm::Value *BoolCondVal = EvaluateExprAsBool(S.getCond());
1107   llvm::MDNode *Weights =
1108       createProfileWeightsForLoop(S.getCond(), getProfileCount(S.getBody()));
1109   if (!Weights && CGM.getCodeGenOpts().OptimizationLevel)
1110     BoolCondVal = emitCondLikelihoodViaExpectIntrinsic(
1111         BoolCondVal, Stmt::getLikelihood(S.getBody()));
1112   Builder.CreateCondBr(BoolCondVal, ForBody, ExitBlock, Weights);
1113 
1114   if (ExitBlock != LoopExit.getBlock()) {
1115     EmitBlock(ExitBlock);
1116     EmitBranchThroughCleanup(LoopExit);
1117   }
1118 
1119   EmitBlock(ForBody);
1120   incrementProfileCounter(&S);
1121 
1122   // Create a block for the increment. In case of a 'continue', we jump there.
1123   JumpDest Continue = getJumpDestInCurrentScope("for.inc");
1124 
1125   // Store the blocks to use for break and continue.
1126   BreakContinueStack.push_back(BreakContinue(LoopExit, Continue));
1127 
1128   {
1129     // Create a separate cleanup scope for the loop variable and body.
1130     LexicalScope BodyScope(*this, S.getSourceRange());
1131     EmitStmt(S.getLoopVarStmt());
1132     EmitStmt(S.getBody());
1133   }
1134 
1135   EmitStopPoint(&S);
1136   // If there is an increment, emit it next.
1137   EmitBlock(Continue.getBlock());
1138   EmitStmt(S.getInc());
1139 
1140   BreakContinueStack.pop_back();
1141 
1142   EmitBranch(CondBlock);
1143 
1144   ForScope.ForceCleanup();
1145 
1146   LoopStack.pop();
1147 
1148   // Emit the fall-through block.
1149   EmitBlock(LoopExit.getBlock(), true);
1150 }
1151 
EmitReturnOfRValue(RValue RV,QualType Ty)1152 void CodeGenFunction::EmitReturnOfRValue(RValue RV, QualType Ty) {
1153   if (RV.isScalar()) {
1154     Builder.CreateStore(RV.getScalarVal(), ReturnValue);
1155   } else if (RV.isAggregate()) {
1156     LValue Dest = MakeAddrLValue(ReturnValue, Ty);
1157     LValue Src = MakeAddrLValue(RV.getAggregateAddress(), Ty);
1158     EmitAggregateCopy(Dest, Src, Ty, getOverlapForReturnValue());
1159   } else {
1160     EmitStoreOfComplex(RV.getComplexVal(), MakeAddrLValue(ReturnValue, Ty),
1161                        /*init*/ true);
1162   }
1163   EmitBranchThroughCleanup(ReturnBlock);
1164 }
1165 
1166 namespace {
1167 // RAII struct used to save and restore a return statment's result expression.
1168 struct SaveRetExprRAII {
SaveRetExprRAII__anond272b0f60111::SaveRetExprRAII1169   SaveRetExprRAII(const Expr *RetExpr, CodeGenFunction &CGF)
1170       : OldRetExpr(CGF.RetExpr), CGF(CGF) {
1171     CGF.RetExpr = RetExpr;
1172   }
~SaveRetExprRAII__anond272b0f60111::SaveRetExprRAII1173   ~SaveRetExprRAII() { CGF.RetExpr = OldRetExpr; }
1174   const Expr *OldRetExpr;
1175   CodeGenFunction &CGF;
1176 };
1177 } // namespace
1178 
1179 /// If we have 'return f(...);', where both caller and callee are SwiftAsync,
1180 /// codegen it as 'tail call ...; ret void;'.
makeTailCallIfSwiftAsync(const CallExpr * CE,CGBuilderTy & Builder,const CGFunctionInfo * CurFnInfo)1181 static void makeTailCallIfSwiftAsync(const CallExpr *CE, CGBuilderTy &Builder,
1182                                      const CGFunctionInfo *CurFnInfo) {
1183   auto calleeQualType = CE->getCallee()->getType();
1184   const FunctionType *calleeType = nullptr;
1185   if (calleeQualType->isFunctionPointerType() ||
1186       calleeQualType->isFunctionReferenceType() ||
1187       calleeQualType->isBlockPointerType() ||
1188       calleeQualType->isMemberFunctionPointerType()) {
1189     calleeType = calleeQualType->getPointeeType()->castAs<FunctionType>();
1190   } else if (auto *ty = dyn_cast<FunctionType>(calleeQualType)) {
1191     calleeType = ty;
1192   } else if (auto CMCE = dyn_cast<CXXMemberCallExpr>(CE)) {
1193     if (auto methodDecl = CMCE->getMethodDecl()) {
1194       // getMethodDecl() doesn't handle member pointers at the moment.
1195       calleeType = methodDecl->getType()->castAs<FunctionType>();
1196     } else {
1197       return;
1198     }
1199   } else {
1200     return;
1201   }
1202   if (calleeType->getCallConv() == CallingConv::CC_SwiftAsync &&
1203       (CurFnInfo->getASTCallingConvention() == CallingConv::CC_SwiftAsync)) {
1204     auto CI = cast<llvm::CallInst>(&Builder.GetInsertBlock()->back());
1205     CI->setTailCallKind(llvm::CallInst::TCK_MustTail);
1206     Builder.CreateRetVoid();
1207     Builder.ClearInsertionPoint();
1208   }
1209 }
1210 
1211 /// EmitReturnStmt - Note that due to GCC extensions, this can have an operand
1212 /// if the function returns void, or may be missing one if the function returns
1213 /// non-void.  Fun stuff :).
EmitReturnStmt(const ReturnStmt & S)1214 void CodeGenFunction::EmitReturnStmt(const ReturnStmt &S) {
1215   if (requiresReturnValueCheck()) {
1216     llvm::Constant *SLoc = EmitCheckSourceLocation(S.getBeginLoc());
1217     auto *SLocPtr =
1218         new llvm::GlobalVariable(CGM.getModule(), SLoc->getType(), false,
1219                                  llvm::GlobalVariable::PrivateLinkage, SLoc);
1220     SLocPtr->setUnnamedAddr(llvm::GlobalValue::UnnamedAddr::Global);
1221     CGM.getSanitizerMetadata()->disableSanitizerForGlobal(SLocPtr);
1222     assert(ReturnLocation.isValid() && "No valid return location");
1223     Builder.CreateStore(Builder.CreateBitCast(SLocPtr, Int8PtrTy),
1224                         ReturnLocation);
1225   }
1226 
1227   // Returning from an outlined SEH helper is UB, and we already warn on it.
1228   if (IsOutlinedSEHHelper) {
1229     Builder.CreateUnreachable();
1230     Builder.ClearInsertionPoint();
1231   }
1232 
1233   // Emit the result value, even if unused, to evaluate the side effects.
1234   const Expr *RV = S.getRetValue();
1235 
1236   // Record the result expression of the return statement. The recorded
1237   // expression is used to determine whether a block capture's lifetime should
1238   // end at the end of the full expression as opposed to the end of the scope
1239   // enclosing the block expression.
1240   //
1241   // This permits a small, easily-implemented exception to our over-conservative
1242   // rules about not jumping to statements following block literals with
1243   // non-trivial cleanups.
1244   SaveRetExprRAII SaveRetExpr(RV, *this);
1245 
1246   RunCleanupsScope cleanupScope(*this);
1247   if (const auto *EWC = dyn_cast_or_null<ExprWithCleanups>(RV))
1248     RV = EWC->getSubExpr();
1249   // FIXME: Clean this up by using an LValue for ReturnTemp,
1250   // EmitStoreThroughLValue, and EmitAnyExpr.
1251   // Check if the NRVO candidate was not globalized in OpenMP mode.
1252   if (getLangOpts().ElideConstructors && S.getNRVOCandidate() &&
1253       S.getNRVOCandidate()->isNRVOVariable() &&
1254       (!getLangOpts().OpenMP ||
1255        !CGM.getOpenMPRuntime()
1256             .getAddressOfLocalVariable(*this, S.getNRVOCandidate())
1257             .isValid())) {
1258     // Apply the named return value optimization for this return statement,
1259     // which means doing nothing: the appropriate result has already been
1260     // constructed into the NRVO variable.
1261 
1262     // If there is an NRVO flag for this variable, set it to 1 into indicate
1263     // that the cleanup code should not destroy the variable.
1264     if (llvm::Value *NRVOFlag = NRVOFlags[S.getNRVOCandidate()])
1265       Builder.CreateFlagStore(Builder.getTrue(), NRVOFlag);
1266   } else if (!ReturnValue.isValid() || (RV && RV->getType()->isVoidType())) {
1267     // Make sure not to return anything, but evaluate the expression
1268     // for side effects.
1269     if (RV) {
1270       EmitAnyExpr(RV);
1271       if (auto *CE = dyn_cast<CallExpr>(RV))
1272         makeTailCallIfSwiftAsync(CE, Builder, CurFnInfo);
1273     }
1274   } else if (!RV) {
1275     // Do nothing (return value is left uninitialized)
1276   } else if (FnRetTy->isReferenceType()) {
1277     // If this function returns a reference, take the address of the expression
1278     // rather than the value.
1279     RValue Result = EmitReferenceBindingToExpr(RV);
1280     Builder.CreateStore(Result.getScalarVal(), ReturnValue);
1281   } else {
1282     switch (getEvaluationKind(RV->getType())) {
1283     case TEK_Scalar:
1284       Builder.CreateStore(EmitScalarExpr(RV), ReturnValue);
1285       break;
1286     case TEK_Complex:
1287       EmitComplexExprIntoLValue(RV, MakeAddrLValue(ReturnValue, RV->getType()),
1288                                 /*isInit*/ true);
1289       break;
1290     case TEK_Aggregate:
1291       EmitAggExpr(RV, AggValueSlot::forAddr(
1292                           ReturnValue, Qualifiers(),
1293                           AggValueSlot::IsDestructed,
1294                           AggValueSlot::DoesNotNeedGCBarriers,
1295                           AggValueSlot::IsNotAliased,
1296                           getOverlapForReturnValue()));
1297       break;
1298     }
1299   }
1300 
1301   ++NumReturnExprs;
1302   if (!RV || RV->isEvaluatable(getContext()))
1303     ++NumSimpleReturnExprs;
1304 
1305   cleanupScope.ForceCleanup();
1306   EmitBranchThroughCleanup(ReturnBlock);
1307 }
1308 
EmitDeclStmt(const DeclStmt & S)1309 void CodeGenFunction::EmitDeclStmt(const DeclStmt &S) {
1310   // As long as debug info is modeled with instructions, we have to ensure we
1311   // have a place to insert here and write the stop point here.
1312   if (HaveInsertPoint())
1313     EmitStopPoint(&S);
1314 
1315   for (const auto *I : S.decls())
1316     EmitDecl(*I);
1317 }
1318 
EmitBreakStmt(const BreakStmt & S)1319 void CodeGenFunction::EmitBreakStmt(const BreakStmt &S) {
1320   assert(!BreakContinueStack.empty() && "break stmt not in a loop or switch!");
1321 
1322   // If this code is reachable then emit a stop point (if generating
1323   // debug info). We have to do this ourselves because we are on the
1324   // "simple" statement path.
1325   if (HaveInsertPoint())
1326     EmitStopPoint(&S);
1327 
1328   EmitBranchThroughCleanup(BreakContinueStack.back().BreakBlock);
1329 }
1330 
EmitContinueStmt(const ContinueStmt & S)1331 void CodeGenFunction::EmitContinueStmt(const ContinueStmt &S) {
1332   assert(!BreakContinueStack.empty() && "continue stmt not in a loop!");
1333 
1334   // If this code is reachable then emit a stop point (if generating
1335   // debug info). We have to do this ourselves because we are on the
1336   // "simple" statement path.
1337   if (HaveInsertPoint())
1338     EmitStopPoint(&S);
1339 
1340   EmitBranchThroughCleanup(BreakContinueStack.back().ContinueBlock);
1341 }
1342 
1343 /// EmitCaseStmtRange - If case statement range is not too big then
1344 /// add multiple cases to switch instruction, one for each value within
1345 /// the range. If range is too big then emit "if" condition check.
EmitCaseStmtRange(const CaseStmt & S,ArrayRef<const Attr * > Attrs)1346 void CodeGenFunction::EmitCaseStmtRange(const CaseStmt &S,
1347                                         ArrayRef<const Attr *> Attrs) {
1348   assert(S.getRHS() && "Expected RHS value in CaseStmt");
1349 
1350   llvm::APSInt LHS = S.getLHS()->EvaluateKnownConstInt(getContext());
1351   llvm::APSInt RHS = S.getRHS()->EvaluateKnownConstInt(getContext());
1352 
1353   // Emit the code for this case. We do this first to make sure it is
1354   // properly chained from our predecessor before generating the
1355   // switch machinery to enter this block.
1356   llvm::BasicBlock *CaseDest = createBasicBlock("sw.bb");
1357   EmitBlockWithFallThrough(CaseDest, &S);
1358   EmitStmt(S.getSubStmt());
1359 
1360   // If range is empty, do nothing.
1361   if (LHS.isSigned() ? RHS.slt(LHS) : RHS.ult(LHS))
1362     return;
1363 
1364   Stmt::Likelihood LH = Stmt::getLikelihood(Attrs);
1365   llvm::APInt Range = RHS - LHS;
1366   // FIXME: parameters such as this should not be hardcoded.
1367   if (Range.ult(llvm::APInt(Range.getBitWidth(), 64))) {
1368     // Range is small enough to add multiple switch instruction cases.
1369     uint64_t Total = getProfileCount(&S);
1370     unsigned NCases = Range.getZExtValue() + 1;
1371     // We only have one region counter for the entire set of cases here, so we
1372     // need to divide the weights evenly between the generated cases, ensuring
1373     // that the total weight is preserved. E.g., a weight of 5 over three cases
1374     // will be distributed as weights of 2, 2, and 1.
1375     uint64_t Weight = Total / NCases, Rem = Total % NCases;
1376     for (unsigned I = 0; I != NCases; ++I) {
1377       if (SwitchWeights)
1378         SwitchWeights->push_back(Weight + (Rem ? 1 : 0));
1379       else if (SwitchLikelihood)
1380         SwitchLikelihood->push_back(LH);
1381 
1382       if (Rem)
1383         Rem--;
1384       SwitchInsn->addCase(Builder.getInt(LHS), CaseDest);
1385       ++LHS;
1386     }
1387     return;
1388   }
1389 
1390   // The range is too big. Emit "if" condition into a new block,
1391   // making sure to save and restore the current insertion point.
1392   llvm::BasicBlock *RestoreBB = Builder.GetInsertBlock();
1393 
1394   // Push this test onto the chain of range checks (which terminates
1395   // in the default basic block). The switch's default will be changed
1396   // to the top of this chain after switch emission is complete.
1397   llvm::BasicBlock *FalseDest = CaseRangeBlock;
1398   CaseRangeBlock = createBasicBlock("sw.caserange");
1399 
1400   CurFn->getBasicBlockList().push_back(CaseRangeBlock);
1401   Builder.SetInsertPoint(CaseRangeBlock);
1402 
1403   // Emit range check.
1404   llvm::Value *Diff =
1405     Builder.CreateSub(SwitchInsn->getCondition(), Builder.getInt(LHS));
1406   llvm::Value *Cond =
1407     Builder.CreateICmpULE(Diff, Builder.getInt(Range), "inbounds");
1408 
1409   llvm::MDNode *Weights = nullptr;
1410   if (SwitchWeights) {
1411     uint64_t ThisCount = getProfileCount(&S);
1412     uint64_t DefaultCount = (*SwitchWeights)[0];
1413     Weights = createProfileWeights(ThisCount, DefaultCount);
1414 
1415     // Since we're chaining the switch default through each large case range, we
1416     // need to update the weight for the default, ie, the first case, to include
1417     // this case.
1418     (*SwitchWeights)[0] += ThisCount;
1419   } else if (SwitchLikelihood)
1420     Cond = emitCondLikelihoodViaExpectIntrinsic(Cond, LH);
1421 
1422   Builder.CreateCondBr(Cond, CaseDest, FalseDest, Weights);
1423 
1424   // Restore the appropriate insertion point.
1425   if (RestoreBB)
1426     Builder.SetInsertPoint(RestoreBB);
1427   else
1428     Builder.ClearInsertionPoint();
1429 }
1430 
EmitCaseStmt(const CaseStmt & S,ArrayRef<const Attr * > Attrs)1431 void CodeGenFunction::EmitCaseStmt(const CaseStmt &S,
1432                                    ArrayRef<const Attr *> Attrs) {
1433   // If there is no enclosing switch instance that we're aware of, then this
1434   // case statement and its block can be elided.  This situation only happens
1435   // when we've constant-folded the switch, are emitting the constant case,
1436   // and part of the constant case includes another case statement.  For
1437   // instance: switch (4) { case 4: do { case 5: } while (1); }
1438   if (!SwitchInsn) {
1439     EmitStmt(S.getSubStmt());
1440     return;
1441   }
1442 
1443   // Handle case ranges.
1444   if (S.getRHS()) {
1445     EmitCaseStmtRange(S, Attrs);
1446     return;
1447   }
1448 
1449   llvm::ConstantInt *CaseVal =
1450     Builder.getInt(S.getLHS()->EvaluateKnownConstInt(getContext()));
1451   if (SwitchLikelihood)
1452     SwitchLikelihood->push_back(Stmt::getLikelihood(Attrs));
1453 
1454   // If the body of the case is just a 'break', try to not emit an empty block.
1455   // If we're profiling or we're not optimizing, leave the block in for better
1456   // debug and coverage analysis.
1457   if (!CGM.getCodeGenOpts().hasProfileClangInstr() &&
1458       CGM.getCodeGenOpts().OptimizationLevel > 0 &&
1459       isa<BreakStmt>(S.getSubStmt())) {
1460     JumpDest Block = BreakContinueStack.back().BreakBlock;
1461 
1462     // Only do this optimization if there are no cleanups that need emitting.
1463     if (isObviouslyBranchWithoutCleanups(Block)) {
1464       if (SwitchWeights)
1465         SwitchWeights->push_back(getProfileCount(&S));
1466       SwitchInsn->addCase(CaseVal, Block.getBlock());
1467 
1468       // If there was a fallthrough into this case, make sure to redirect it to
1469       // the end of the switch as well.
1470       if (Builder.GetInsertBlock()) {
1471         Builder.CreateBr(Block.getBlock());
1472         Builder.ClearInsertionPoint();
1473       }
1474       return;
1475     }
1476   }
1477 
1478   llvm::BasicBlock *CaseDest = createBasicBlock("sw.bb");
1479   EmitBlockWithFallThrough(CaseDest, &S);
1480   if (SwitchWeights)
1481     SwitchWeights->push_back(getProfileCount(&S));
1482   SwitchInsn->addCase(CaseVal, CaseDest);
1483 
1484   // Recursively emitting the statement is acceptable, but is not wonderful for
1485   // code where we have many case statements nested together, i.e.:
1486   //  case 1:
1487   //    case 2:
1488   //      case 3: etc.
1489   // Handling this recursively will create a new block for each case statement
1490   // that falls through to the next case which is IR intensive.  It also causes
1491   // deep recursion which can run into stack depth limitations.  Handle
1492   // sequential non-range case statements specially.
1493   //
1494   // TODO When the next case has a likelihood attribute the code returns to the
1495   // recursive algorithm. Maybe improve this case if it becomes common practice
1496   // to use a lot of attributes.
1497   const CaseStmt *CurCase = &S;
1498   const CaseStmt *NextCase = dyn_cast<CaseStmt>(S.getSubStmt());
1499 
1500   // Otherwise, iteratively add consecutive cases to this switch stmt.
1501   while (NextCase && NextCase->getRHS() == nullptr) {
1502     CurCase = NextCase;
1503     llvm::ConstantInt *CaseVal =
1504       Builder.getInt(CurCase->getLHS()->EvaluateKnownConstInt(getContext()));
1505 
1506     if (SwitchWeights)
1507       SwitchWeights->push_back(getProfileCount(NextCase));
1508     if (CGM.getCodeGenOpts().hasProfileClangInstr()) {
1509       CaseDest = createBasicBlock("sw.bb");
1510       EmitBlockWithFallThrough(CaseDest, CurCase);
1511     }
1512     // Since this loop is only executed when the CaseStmt has no attributes
1513     // use a hard-coded value.
1514     if (SwitchLikelihood)
1515       SwitchLikelihood->push_back(Stmt::LH_None);
1516 
1517     SwitchInsn->addCase(CaseVal, CaseDest);
1518     NextCase = dyn_cast<CaseStmt>(CurCase->getSubStmt());
1519   }
1520 
1521   // Normal default recursion for non-cases.
1522   EmitStmt(CurCase->getSubStmt());
1523 }
1524 
EmitDefaultStmt(const DefaultStmt & S,ArrayRef<const Attr * > Attrs)1525 void CodeGenFunction::EmitDefaultStmt(const DefaultStmt &S,
1526                                       ArrayRef<const Attr *> Attrs) {
1527   // If there is no enclosing switch instance that we're aware of, then this
1528   // default statement can be elided. This situation only happens when we've
1529   // constant-folded the switch.
1530   if (!SwitchInsn) {
1531     EmitStmt(S.getSubStmt());
1532     return;
1533   }
1534 
1535   llvm::BasicBlock *DefaultBlock = SwitchInsn->getDefaultDest();
1536   assert(DefaultBlock->empty() &&
1537          "EmitDefaultStmt: Default block already defined?");
1538 
1539   if (SwitchLikelihood)
1540     SwitchLikelihood->front() = Stmt::getLikelihood(Attrs);
1541 
1542   EmitBlockWithFallThrough(DefaultBlock, &S);
1543 
1544   EmitStmt(S.getSubStmt());
1545 }
1546 
1547 /// CollectStatementsForCase - Given the body of a 'switch' statement and a
1548 /// constant value that is being switched on, see if we can dead code eliminate
1549 /// the body of the switch to a simple series of statements to emit.  Basically,
1550 /// on a switch (5) we want to find these statements:
1551 ///    case 5:
1552 ///      printf(...);    <--
1553 ///      ++i;            <--
1554 ///      break;
1555 ///
1556 /// and add them to the ResultStmts vector.  If it is unsafe to do this
1557 /// transformation (for example, one of the elided statements contains a label
1558 /// that might be jumped to), return CSFC_Failure.  If we handled it and 'S'
1559 /// should include statements after it (e.g. the printf() line is a substmt of
1560 /// the case) then return CSFC_FallThrough.  If we handled it and found a break
1561 /// statement, then return CSFC_Success.
1562 ///
1563 /// If Case is non-null, then we are looking for the specified case, checking
1564 /// that nothing we jump over contains labels.  If Case is null, then we found
1565 /// the case and are looking for the break.
1566 ///
1567 /// If the recursive walk actually finds our Case, then we set FoundCase to
1568 /// true.
1569 ///
1570 enum CSFC_Result { CSFC_Failure, CSFC_FallThrough, CSFC_Success };
CollectStatementsForCase(const Stmt * S,const SwitchCase * Case,bool & FoundCase,SmallVectorImpl<const Stmt * > & ResultStmts)1571 static CSFC_Result CollectStatementsForCase(const Stmt *S,
1572                                             const SwitchCase *Case,
1573                                             bool &FoundCase,
1574                               SmallVectorImpl<const Stmt*> &ResultStmts) {
1575   // If this is a null statement, just succeed.
1576   if (!S)
1577     return Case ? CSFC_Success : CSFC_FallThrough;
1578 
1579   // If this is the switchcase (case 4: or default) that we're looking for, then
1580   // we're in business.  Just add the substatement.
1581   if (const SwitchCase *SC = dyn_cast<SwitchCase>(S)) {
1582     if (S == Case) {
1583       FoundCase = true;
1584       return CollectStatementsForCase(SC->getSubStmt(), nullptr, FoundCase,
1585                                       ResultStmts);
1586     }
1587 
1588     // Otherwise, this is some other case or default statement, just ignore it.
1589     return CollectStatementsForCase(SC->getSubStmt(), Case, FoundCase,
1590                                     ResultStmts);
1591   }
1592 
1593   // If we are in the live part of the code and we found our break statement,
1594   // return a success!
1595   if (!Case && isa<BreakStmt>(S))
1596     return CSFC_Success;
1597 
1598   // If this is a switch statement, then it might contain the SwitchCase, the
1599   // break, or neither.
1600   if (const CompoundStmt *CS = dyn_cast<CompoundStmt>(S)) {
1601     // Handle this as two cases: we might be looking for the SwitchCase (if so
1602     // the skipped statements must be skippable) or we might already have it.
1603     CompoundStmt::const_body_iterator I = CS->body_begin(), E = CS->body_end();
1604     bool StartedInLiveCode = FoundCase;
1605     unsigned StartSize = ResultStmts.size();
1606 
1607     // If we've not found the case yet, scan through looking for it.
1608     if (Case) {
1609       // Keep track of whether we see a skipped declaration.  The code could be
1610       // using the declaration even if it is skipped, so we can't optimize out
1611       // the decl if the kept statements might refer to it.
1612       bool HadSkippedDecl = false;
1613 
1614       // If we're looking for the case, just see if we can skip each of the
1615       // substatements.
1616       for (; Case && I != E; ++I) {
1617         HadSkippedDecl |= CodeGenFunction::mightAddDeclToScope(*I);
1618 
1619         switch (CollectStatementsForCase(*I, Case, FoundCase, ResultStmts)) {
1620         case CSFC_Failure: return CSFC_Failure;
1621         case CSFC_Success:
1622           // A successful result means that either 1) that the statement doesn't
1623           // have the case and is skippable, or 2) does contain the case value
1624           // and also contains the break to exit the switch.  In the later case,
1625           // we just verify the rest of the statements are elidable.
1626           if (FoundCase) {
1627             // If we found the case and skipped declarations, we can't do the
1628             // optimization.
1629             if (HadSkippedDecl)
1630               return CSFC_Failure;
1631 
1632             for (++I; I != E; ++I)
1633               if (CodeGenFunction::ContainsLabel(*I, true))
1634                 return CSFC_Failure;
1635             return CSFC_Success;
1636           }
1637           break;
1638         case CSFC_FallThrough:
1639           // If we have a fallthrough condition, then we must have found the
1640           // case started to include statements.  Consider the rest of the
1641           // statements in the compound statement as candidates for inclusion.
1642           assert(FoundCase && "Didn't find case but returned fallthrough?");
1643           // We recursively found Case, so we're not looking for it anymore.
1644           Case = nullptr;
1645 
1646           // If we found the case and skipped declarations, we can't do the
1647           // optimization.
1648           if (HadSkippedDecl)
1649             return CSFC_Failure;
1650           break;
1651         }
1652       }
1653 
1654       if (!FoundCase)
1655         return CSFC_Success;
1656 
1657       assert(!HadSkippedDecl && "fallthrough after skipping decl");
1658     }
1659 
1660     // If we have statements in our range, then we know that the statements are
1661     // live and need to be added to the set of statements we're tracking.
1662     bool AnyDecls = false;
1663     for (; I != E; ++I) {
1664       AnyDecls |= CodeGenFunction::mightAddDeclToScope(*I);
1665 
1666       switch (CollectStatementsForCase(*I, nullptr, FoundCase, ResultStmts)) {
1667       case CSFC_Failure: return CSFC_Failure;
1668       case CSFC_FallThrough:
1669         // A fallthrough result means that the statement was simple and just
1670         // included in ResultStmt, keep adding them afterwards.
1671         break;
1672       case CSFC_Success:
1673         // A successful result means that we found the break statement and
1674         // stopped statement inclusion.  We just ensure that any leftover stmts
1675         // are skippable and return success ourselves.
1676         for (++I; I != E; ++I)
1677           if (CodeGenFunction::ContainsLabel(*I, true))
1678             return CSFC_Failure;
1679         return CSFC_Success;
1680       }
1681     }
1682 
1683     // If we're about to fall out of a scope without hitting a 'break;', we
1684     // can't perform the optimization if there were any decls in that scope
1685     // (we'd lose their end-of-lifetime).
1686     if (AnyDecls) {
1687       // If the entire compound statement was live, there's one more thing we
1688       // can try before giving up: emit the whole thing as a single statement.
1689       // We can do that unless the statement contains a 'break;'.
1690       // FIXME: Such a break must be at the end of a construct within this one.
1691       // We could emit this by just ignoring the BreakStmts entirely.
1692       if (StartedInLiveCode && !CodeGenFunction::containsBreak(S)) {
1693         ResultStmts.resize(StartSize);
1694         ResultStmts.push_back(S);
1695       } else {
1696         return CSFC_Failure;
1697       }
1698     }
1699 
1700     return CSFC_FallThrough;
1701   }
1702 
1703   // Okay, this is some other statement that we don't handle explicitly, like a
1704   // for statement or increment etc.  If we are skipping over this statement,
1705   // just verify it doesn't have labels, which would make it invalid to elide.
1706   if (Case) {
1707     if (CodeGenFunction::ContainsLabel(S, true))
1708       return CSFC_Failure;
1709     return CSFC_Success;
1710   }
1711 
1712   // Otherwise, we want to include this statement.  Everything is cool with that
1713   // so long as it doesn't contain a break out of the switch we're in.
1714   if (CodeGenFunction::containsBreak(S)) return CSFC_Failure;
1715 
1716   // Otherwise, everything is great.  Include the statement and tell the caller
1717   // that we fall through and include the next statement as well.
1718   ResultStmts.push_back(S);
1719   return CSFC_FallThrough;
1720 }
1721 
1722 /// FindCaseStatementsForValue - Find the case statement being jumped to and
1723 /// then invoke CollectStatementsForCase to find the list of statements to emit
1724 /// for a switch on constant.  See the comment above CollectStatementsForCase
1725 /// for more details.
FindCaseStatementsForValue(const SwitchStmt & S,const llvm::APSInt & ConstantCondValue,SmallVectorImpl<const Stmt * > & ResultStmts,ASTContext & C,const SwitchCase * & ResultCase)1726 static bool FindCaseStatementsForValue(const SwitchStmt &S,
1727                                        const llvm::APSInt &ConstantCondValue,
1728                                 SmallVectorImpl<const Stmt*> &ResultStmts,
1729                                        ASTContext &C,
1730                                        const SwitchCase *&ResultCase) {
1731   // First step, find the switch case that is being branched to.  We can do this
1732   // efficiently by scanning the SwitchCase list.
1733   const SwitchCase *Case = S.getSwitchCaseList();
1734   const DefaultStmt *DefaultCase = nullptr;
1735 
1736   for (; Case; Case = Case->getNextSwitchCase()) {
1737     // It's either a default or case.  Just remember the default statement in
1738     // case we're not jumping to any numbered cases.
1739     if (const DefaultStmt *DS = dyn_cast<DefaultStmt>(Case)) {
1740       DefaultCase = DS;
1741       continue;
1742     }
1743 
1744     // Check to see if this case is the one we're looking for.
1745     const CaseStmt *CS = cast<CaseStmt>(Case);
1746     // Don't handle case ranges yet.
1747     if (CS->getRHS()) return false;
1748 
1749     // If we found our case, remember it as 'case'.
1750     if (CS->getLHS()->EvaluateKnownConstInt(C) == ConstantCondValue)
1751       break;
1752   }
1753 
1754   // If we didn't find a matching case, we use a default if it exists, or we
1755   // elide the whole switch body!
1756   if (!Case) {
1757     // It is safe to elide the body of the switch if it doesn't contain labels
1758     // etc.  If it is safe, return successfully with an empty ResultStmts list.
1759     if (!DefaultCase)
1760       return !CodeGenFunction::ContainsLabel(&S);
1761     Case = DefaultCase;
1762   }
1763 
1764   // Ok, we know which case is being jumped to, try to collect all the
1765   // statements that follow it.  This can fail for a variety of reasons.  Also,
1766   // check to see that the recursive walk actually found our case statement.
1767   // Insane cases like this can fail to find it in the recursive walk since we
1768   // don't handle every stmt kind:
1769   // switch (4) {
1770   //   while (1) {
1771   //     case 4: ...
1772   bool FoundCase = false;
1773   ResultCase = Case;
1774   return CollectStatementsForCase(S.getBody(), Case, FoundCase,
1775                                   ResultStmts) != CSFC_Failure &&
1776          FoundCase;
1777 }
1778 
1779 static Optional<SmallVector<uint64_t, 16>>
getLikelihoodWeights(ArrayRef<Stmt::Likelihood> Likelihoods)1780 getLikelihoodWeights(ArrayRef<Stmt::Likelihood> Likelihoods) {
1781   // Are there enough branches to weight them?
1782   if (Likelihoods.size() <= 1)
1783     return None;
1784 
1785   uint64_t NumUnlikely = 0;
1786   uint64_t NumNone = 0;
1787   uint64_t NumLikely = 0;
1788   for (const auto LH : Likelihoods) {
1789     switch (LH) {
1790     case Stmt::LH_Unlikely:
1791       ++NumUnlikely;
1792       break;
1793     case Stmt::LH_None:
1794       ++NumNone;
1795       break;
1796     case Stmt::LH_Likely:
1797       ++NumLikely;
1798       break;
1799     }
1800   }
1801 
1802   // Is there a likelihood attribute used?
1803   if (NumUnlikely == 0 && NumLikely == 0)
1804     return None;
1805 
1806   // When multiple cases share the same code they can be combined during
1807   // optimization. In that case the weights of the branch will be the sum of
1808   // the individual weights. Make sure the combined sum of all neutral cases
1809   // doesn't exceed the value of a single likely attribute.
1810   // The additions both avoid divisions by 0 and make sure the weights of None
1811   // don't exceed the weight of Likely.
1812   const uint64_t Likely = INT32_MAX / (NumLikely + 2);
1813   const uint64_t None = Likely / (NumNone + 1);
1814   const uint64_t Unlikely = 0;
1815 
1816   SmallVector<uint64_t, 16> Result;
1817   Result.reserve(Likelihoods.size());
1818   for (const auto LH : Likelihoods) {
1819     switch (LH) {
1820     case Stmt::LH_Unlikely:
1821       Result.push_back(Unlikely);
1822       break;
1823     case Stmt::LH_None:
1824       Result.push_back(None);
1825       break;
1826     case Stmt::LH_Likely:
1827       Result.push_back(Likely);
1828       break;
1829     }
1830   }
1831 
1832   return Result;
1833 }
1834 
EmitSwitchStmt(const SwitchStmt & S)1835 void CodeGenFunction::EmitSwitchStmt(const SwitchStmt &S) {
1836   // Handle nested switch statements.
1837   llvm::SwitchInst *SavedSwitchInsn = SwitchInsn;
1838   SmallVector<uint64_t, 16> *SavedSwitchWeights = SwitchWeights;
1839   SmallVector<Stmt::Likelihood, 16> *SavedSwitchLikelihood = SwitchLikelihood;
1840   llvm::BasicBlock *SavedCRBlock = CaseRangeBlock;
1841 
1842   // See if we can constant fold the condition of the switch and therefore only
1843   // emit the live case statement (if any) of the switch.
1844   llvm::APSInt ConstantCondValue;
1845   if (ConstantFoldsToSimpleInteger(S.getCond(), ConstantCondValue)) {
1846     SmallVector<const Stmt*, 4> CaseStmts;
1847     const SwitchCase *Case = nullptr;
1848     if (FindCaseStatementsForValue(S, ConstantCondValue, CaseStmts,
1849                                    getContext(), Case)) {
1850       if (Case)
1851         incrementProfileCounter(Case);
1852       RunCleanupsScope ExecutedScope(*this);
1853 
1854       if (S.getInit())
1855         EmitStmt(S.getInit());
1856 
1857       // Emit the condition variable if needed inside the entire cleanup scope
1858       // used by this special case for constant folded switches.
1859       if (S.getConditionVariable())
1860         EmitDecl(*S.getConditionVariable());
1861 
1862       // At this point, we are no longer "within" a switch instance, so
1863       // we can temporarily enforce this to ensure that any embedded case
1864       // statements are not emitted.
1865       SwitchInsn = nullptr;
1866 
1867       // Okay, we can dead code eliminate everything except this case.  Emit the
1868       // specified series of statements and we're good.
1869       for (unsigned i = 0, e = CaseStmts.size(); i != e; ++i)
1870         EmitStmt(CaseStmts[i]);
1871       incrementProfileCounter(&S);
1872 
1873       // Now we want to restore the saved switch instance so that nested
1874       // switches continue to function properly
1875       SwitchInsn = SavedSwitchInsn;
1876 
1877       return;
1878     }
1879   }
1880 
1881   JumpDest SwitchExit = getJumpDestInCurrentScope("sw.epilog");
1882 
1883   RunCleanupsScope ConditionScope(*this);
1884 
1885   if (S.getInit())
1886     EmitStmt(S.getInit());
1887 
1888   if (S.getConditionVariable())
1889     EmitDecl(*S.getConditionVariable());
1890   llvm::Value *CondV = EmitScalarExpr(S.getCond());
1891 
1892   // Create basic block to hold stuff that comes after switch
1893   // statement. We also need to create a default block now so that
1894   // explicit case ranges tests can have a place to jump to on
1895   // failure.
1896   llvm::BasicBlock *DefaultBlock = createBasicBlock("sw.default");
1897   SwitchInsn = Builder.CreateSwitch(CondV, DefaultBlock);
1898   if (PGO.haveRegionCounts()) {
1899     // Walk the SwitchCase list to find how many there are.
1900     uint64_t DefaultCount = 0;
1901     unsigned NumCases = 0;
1902     for (const SwitchCase *Case = S.getSwitchCaseList();
1903          Case;
1904          Case = Case->getNextSwitchCase()) {
1905       if (isa<DefaultStmt>(Case))
1906         DefaultCount = getProfileCount(Case);
1907       NumCases += 1;
1908     }
1909     SwitchWeights = new SmallVector<uint64_t, 16>();
1910     SwitchWeights->reserve(NumCases);
1911     // The default needs to be first. We store the edge count, so we already
1912     // know the right weight.
1913     SwitchWeights->push_back(DefaultCount);
1914   } else if (CGM.getCodeGenOpts().OptimizationLevel) {
1915     SwitchLikelihood = new SmallVector<Stmt::Likelihood, 16>();
1916     // Initialize the default case.
1917     SwitchLikelihood->push_back(Stmt::LH_None);
1918   }
1919 
1920   CaseRangeBlock = DefaultBlock;
1921 
1922   // Clear the insertion point to indicate we are in unreachable code.
1923   Builder.ClearInsertionPoint();
1924 
1925   // All break statements jump to NextBlock. If BreakContinueStack is non-empty
1926   // then reuse last ContinueBlock.
1927   JumpDest OuterContinue;
1928   if (!BreakContinueStack.empty())
1929     OuterContinue = BreakContinueStack.back().ContinueBlock;
1930 
1931   BreakContinueStack.push_back(BreakContinue(SwitchExit, OuterContinue));
1932 
1933   // Emit switch body.
1934   EmitStmt(S.getBody());
1935 
1936   BreakContinueStack.pop_back();
1937 
1938   // Update the default block in case explicit case range tests have
1939   // been chained on top.
1940   SwitchInsn->setDefaultDest(CaseRangeBlock);
1941 
1942   // If a default was never emitted:
1943   if (!DefaultBlock->getParent()) {
1944     // If we have cleanups, emit the default block so that there's a
1945     // place to jump through the cleanups from.
1946     if (ConditionScope.requiresCleanups()) {
1947       EmitBlock(DefaultBlock);
1948 
1949     // Otherwise, just forward the default block to the switch end.
1950     } else {
1951       DefaultBlock->replaceAllUsesWith(SwitchExit.getBlock());
1952       delete DefaultBlock;
1953     }
1954   }
1955 
1956   ConditionScope.ForceCleanup();
1957 
1958   // Emit continuation.
1959   EmitBlock(SwitchExit.getBlock(), true);
1960   incrementProfileCounter(&S);
1961 
1962   // If the switch has a condition wrapped by __builtin_unpredictable,
1963   // create metadata that specifies that the switch is unpredictable.
1964   // Don't bother if not optimizing because that metadata would not be used.
1965   auto *Call = dyn_cast<CallExpr>(S.getCond());
1966   if (Call && CGM.getCodeGenOpts().OptimizationLevel != 0) {
1967     auto *FD = dyn_cast_or_null<FunctionDecl>(Call->getCalleeDecl());
1968     if (FD && FD->getBuiltinID() == Builtin::BI__builtin_unpredictable) {
1969       llvm::MDBuilder MDHelper(getLLVMContext());
1970       SwitchInsn->setMetadata(llvm::LLVMContext::MD_unpredictable,
1971                               MDHelper.createUnpredictable());
1972     }
1973   }
1974 
1975   if (SwitchWeights) {
1976     assert(SwitchWeights->size() == 1 + SwitchInsn->getNumCases() &&
1977            "switch weights do not match switch cases");
1978     // If there's only one jump destination there's no sense weighting it.
1979     if (SwitchWeights->size() > 1)
1980       SwitchInsn->setMetadata(llvm::LLVMContext::MD_prof,
1981                               createProfileWeights(*SwitchWeights));
1982     delete SwitchWeights;
1983   } else if (SwitchLikelihood) {
1984     assert(SwitchLikelihood->size() == 1 + SwitchInsn->getNumCases() &&
1985            "switch likelihoods do not match switch cases");
1986     Optional<SmallVector<uint64_t, 16>> LHW =
1987         getLikelihoodWeights(*SwitchLikelihood);
1988     if (LHW) {
1989       llvm::MDBuilder MDHelper(CGM.getLLVMContext());
1990       SwitchInsn->setMetadata(llvm::LLVMContext::MD_prof,
1991                               createProfileWeights(*LHW));
1992     }
1993     delete SwitchLikelihood;
1994   }
1995   SwitchInsn = SavedSwitchInsn;
1996   SwitchWeights = SavedSwitchWeights;
1997   SwitchLikelihood = SavedSwitchLikelihood;
1998   CaseRangeBlock = SavedCRBlock;
1999 }
2000 
2001 static std::string
SimplifyConstraint(const char * Constraint,const TargetInfo & Target,SmallVectorImpl<TargetInfo::ConstraintInfo> * OutCons=nullptr)2002 SimplifyConstraint(const char *Constraint, const TargetInfo &Target,
2003                  SmallVectorImpl<TargetInfo::ConstraintInfo> *OutCons=nullptr) {
2004   std::string Result;
2005 
2006   while (*Constraint) {
2007     switch (*Constraint) {
2008     default:
2009       Result += Target.convertConstraint(Constraint);
2010       break;
2011     // Ignore these
2012     case '*':
2013     case '?':
2014     case '!':
2015     case '=': // Will see this and the following in mult-alt constraints.
2016     case '+':
2017       break;
2018     case '#': // Ignore the rest of the constraint alternative.
2019       while (Constraint[1] && Constraint[1] != ',')
2020         Constraint++;
2021       break;
2022     case '&':
2023     case '%':
2024       Result += *Constraint;
2025       while (Constraint[1] && Constraint[1] == *Constraint)
2026         Constraint++;
2027       break;
2028     case ',':
2029       Result += "|";
2030       break;
2031     case 'g':
2032       Result += "imr";
2033       break;
2034     case '[': {
2035       assert(OutCons &&
2036              "Must pass output names to constraints with a symbolic name");
2037       unsigned Index;
2038       bool result = Target.resolveSymbolicName(Constraint, *OutCons, Index);
2039       assert(result && "Could not resolve symbolic name"); (void)result;
2040       Result += llvm::utostr(Index);
2041       break;
2042     }
2043     }
2044 
2045     Constraint++;
2046   }
2047 
2048   return Result;
2049 }
2050 
2051 /// AddVariableConstraints - Look at AsmExpr and if it is a variable declared
2052 /// as using a particular register add that as a constraint that will be used
2053 /// in this asm stmt.
2054 static std::string
AddVariableConstraints(const std::string & Constraint,const Expr & AsmExpr,const TargetInfo & Target,CodeGenModule & CGM,const AsmStmt & Stmt,const bool EarlyClobber,std::string * GCCReg=nullptr)2055 AddVariableConstraints(const std::string &Constraint, const Expr &AsmExpr,
2056                        const TargetInfo &Target, CodeGenModule &CGM,
2057                        const AsmStmt &Stmt, const bool EarlyClobber,
2058                        std::string *GCCReg = nullptr) {
2059   const DeclRefExpr *AsmDeclRef = dyn_cast<DeclRefExpr>(&AsmExpr);
2060   if (!AsmDeclRef)
2061     return Constraint;
2062   const ValueDecl &Value = *AsmDeclRef->getDecl();
2063   const VarDecl *Variable = dyn_cast<VarDecl>(&Value);
2064   if (!Variable)
2065     return Constraint;
2066   if (Variable->getStorageClass() != SC_Register)
2067     return Constraint;
2068   AsmLabelAttr *Attr = Variable->getAttr<AsmLabelAttr>();
2069   if (!Attr)
2070     return Constraint;
2071   StringRef Register = Attr->getLabel();
2072   assert(Target.isValidGCCRegisterName(Register));
2073   // We're using validateOutputConstraint here because we only care if
2074   // this is a register constraint.
2075   TargetInfo::ConstraintInfo Info(Constraint, "");
2076   if (Target.validateOutputConstraint(Info) &&
2077       !Info.allowsRegister()) {
2078     CGM.ErrorUnsupported(&Stmt, "__asm__");
2079     return Constraint;
2080   }
2081   // Canonicalize the register here before returning it.
2082   Register = Target.getNormalizedGCCRegisterName(Register);
2083   if (GCCReg != nullptr)
2084     *GCCReg = Register.str();
2085   return (EarlyClobber ? "&{" : "{") + Register.str() + "}";
2086 }
2087 
2088 llvm::Value*
EmitAsmInputLValue(const TargetInfo::ConstraintInfo & Info,LValue InputValue,QualType InputType,std::string & ConstraintStr,SourceLocation Loc)2089 CodeGenFunction::EmitAsmInputLValue(const TargetInfo::ConstraintInfo &Info,
2090                                     LValue InputValue, QualType InputType,
2091                                     std::string &ConstraintStr,
2092                                     SourceLocation Loc) {
2093   llvm::Value *Arg;
2094   if (Info.allowsRegister() || !Info.allowsMemory()) {
2095     if (CodeGenFunction::hasScalarEvaluationKind(InputType)) {
2096       Arg = EmitLoadOfLValue(InputValue, Loc).getScalarVal();
2097     } else {
2098       llvm::Type *Ty = ConvertType(InputType);
2099       uint64_t Size = CGM.getDataLayout().getTypeSizeInBits(Ty);
2100       if ((Size <= 64 && llvm::isPowerOf2_64(Size)) ||
2101           getTargetHooks().isScalarizableAsmOperand(*this, Ty)) {
2102         Ty = llvm::IntegerType::get(getLLVMContext(), Size);
2103         Ty = llvm::PointerType::getUnqual(Ty);
2104 
2105         Arg = Builder.CreateLoad(
2106             Builder.CreateBitCast(InputValue.getAddress(*this), Ty));
2107       } else {
2108         Arg = InputValue.getPointer(*this);
2109         ConstraintStr += '*';
2110       }
2111     }
2112   } else {
2113     Arg = InputValue.getPointer(*this);
2114     ConstraintStr += '*';
2115   }
2116 
2117   return Arg;
2118 }
2119 
EmitAsmInput(const TargetInfo::ConstraintInfo & Info,const Expr * InputExpr,std::string & ConstraintStr)2120 llvm::Value* CodeGenFunction::EmitAsmInput(
2121                                          const TargetInfo::ConstraintInfo &Info,
2122                                            const Expr *InputExpr,
2123                                            std::string &ConstraintStr) {
2124   // If this can't be a register or memory, i.e., has to be a constant
2125   // (immediate or symbolic), try to emit it as such.
2126   if (!Info.allowsRegister() && !Info.allowsMemory()) {
2127     if (Info.requiresImmediateConstant()) {
2128       Expr::EvalResult EVResult;
2129       InputExpr->EvaluateAsRValue(EVResult, getContext(), true);
2130 
2131       llvm::APSInt IntResult;
2132       if (EVResult.Val.toIntegralConstant(IntResult, InputExpr->getType(),
2133                                           getContext()))
2134         return llvm::ConstantInt::get(getLLVMContext(), IntResult);
2135     }
2136 
2137     Expr::EvalResult Result;
2138     if (InputExpr->EvaluateAsInt(Result, getContext()))
2139       return llvm::ConstantInt::get(getLLVMContext(), Result.Val.getInt());
2140   }
2141 
2142   if (Info.allowsRegister() || !Info.allowsMemory())
2143     if (CodeGenFunction::hasScalarEvaluationKind(InputExpr->getType()))
2144       return EmitScalarExpr(InputExpr);
2145   if (InputExpr->getStmtClass() == Expr::CXXThisExprClass)
2146     return EmitScalarExpr(InputExpr);
2147   InputExpr = InputExpr->IgnoreParenNoopCasts(getContext());
2148   LValue Dest = EmitLValue(InputExpr);
2149   return EmitAsmInputLValue(Info, Dest, InputExpr->getType(), ConstraintStr,
2150                             InputExpr->getExprLoc());
2151 }
2152 
2153 /// getAsmSrcLocInfo - Return the !srcloc metadata node to attach to an inline
2154 /// asm call instruction.  The !srcloc MDNode contains a list of constant
2155 /// integers which are the source locations of the start of each line in the
2156 /// asm.
getAsmSrcLocInfo(const StringLiteral * Str,CodeGenFunction & CGF)2157 static llvm::MDNode *getAsmSrcLocInfo(const StringLiteral *Str,
2158                                       CodeGenFunction &CGF) {
2159   SmallVector<llvm::Metadata *, 8> Locs;
2160   // Add the location of the first line to the MDNode.
2161   Locs.push_back(llvm::ConstantAsMetadata::get(llvm::ConstantInt::get(
2162       CGF.Int64Ty, Str->getBeginLoc().getRawEncoding())));
2163   StringRef StrVal = Str->getString();
2164   if (!StrVal.empty()) {
2165     const SourceManager &SM = CGF.CGM.getContext().getSourceManager();
2166     const LangOptions &LangOpts = CGF.CGM.getLangOpts();
2167     unsigned StartToken = 0;
2168     unsigned ByteOffset = 0;
2169 
2170     // Add the location of the start of each subsequent line of the asm to the
2171     // MDNode.
2172     for (unsigned i = 0, e = StrVal.size() - 1; i != e; ++i) {
2173       if (StrVal[i] != '\n') continue;
2174       SourceLocation LineLoc = Str->getLocationOfByte(
2175           i + 1, SM, LangOpts, CGF.getTarget(), &StartToken, &ByteOffset);
2176       Locs.push_back(llvm::ConstantAsMetadata::get(
2177           llvm::ConstantInt::get(CGF.Int64Ty, LineLoc.getRawEncoding())));
2178     }
2179   }
2180 
2181   return llvm::MDNode::get(CGF.getLLVMContext(), Locs);
2182 }
2183 
UpdateAsmCallInst(llvm::CallBase & Result,bool HasSideEffect,bool HasUnwindClobber,bool ReadOnly,bool ReadNone,bool NoMerge,const AsmStmt & S,const std::vector<llvm::Type * > & ResultRegTypes,CodeGenFunction & CGF,std::vector<llvm::Value * > & RegResults)2184 static void UpdateAsmCallInst(llvm::CallBase &Result, bool HasSideEffect,
2185                               bool HasUnwindClobber, bool ReadOnly,
2186                               bool ReadNone, bool NoMerge, const AsmStmt &S,
2187                               const std::vector<llvm::Type *> &ResultRegTypes,
2188                               CodeGenFunction &CGF,
2189                               std::vector<llvm::Value *> &RegResults) {
2190   if (!HasUnwindClobber)
2191     Result.addAttribute(llvm::AttributeList::FunctionIndex,
2192                         llvm::Attribute::NoUnwind);
2193 
2194   if (NoMerge)
2195     Result.addAttribute(llvm::AttributeList::FunctionIndex,
2196                         llvm::Attribute::NoMerge);
2197   // Attach readnone and readonly attributes.
2198   if (!HasSideEffect) {
2199     if (ReadNone)
2200       Result.addAttribute(llvm::AttributeList::FunctionIndex,
2201                           llvm::Attribute::ReadNone);
2202     else if (ReadOnly)
2203       Result.addAttribute(llvm::AttributeList::FunctionIndex,
2204                           llvm::Attribute::ReadOnly);
2205   }
2206 
2207   // Slap the source location of the inline asm into a !srcloc metadata on the
2208   // call.
2209   if (const auto *gccAsmStmt = dyn_cast<GCCAsmStmt>(&S))
2210     Result.setMetadata("srcloc",
2211                        getAsmSrcLocInfo(gccAsmStmt->getAsmString(), CGF));
2212   else {
2213     // At least put the line number on MS inline asm blobs.
2214     llvm::Constant *Loc =
2215         llvm::ConstantInt::get(CGF.Int64Ty, S.getAsmLoc().getRawEncoding());
2216     Result.setMetadata("srcloc",
2217                        llvm::MDNode::get(CGF.getLLVMContext(),
2218                                          llvm::ConstantAsMetadata::get(Loc)));
2219   }
2220 
2221   if (CGF.getLangOpts().assumeFunctionsAreConvergent())
2222     // Conservatively, mark all inline asm blocks in CUDA or OpenCL as
2223     // convergent (meaning, they may call an intrinsically convergent op, such
2224     // as bar.sync, and so can't have certain optimizations applied around
2225     // them).
2226     Result.addAttribute(llvm::AttributeList::FunctionIndex,
2227                         llvm::Attribute::Convergent);
2228   // Extract all of the register value results from the asm.
2229   if (ResultRegTypes.size() == 1) {
2230     RegResults.push_back(&Result);
2231   } else {
2232     for (unsigned i = 0, e = ResultRegTypes.size(); i != e; ++i) {
2233       llvm::Value *Tmp = CGF.Builder.CreateExtractValue(&Result, i, "asmresult");
2234       RegResults.push_back(Tmp);
2235     }
2236   }
2237 }
2238 
EmitAsmStmt(const AsmStmt & S)2239 void CodeGenFunction::EmitAsmStmt(const AsmStmt &S) {
2240   // Assemble the final asm string.
2241   std::string AsmString = S.generateAsmString(getContext());
2242 
2243   // Get all the output and input constraints together.
2244   SmallVector<TargetInfo::ConstraintInfo, 4> OutputConstraintInfos;
2245   SmallVector<TargetInfo::ConstraintInfo, 4> InputConstraintInfos;
2246 
2247   for (unsigned i = 0, e = S.getNumOutputs(); i != e; i++) {
2248     StringRef Name;
2249     if (const GCCAsmStmt *GAS = dyn_cast<GCCAsmStmt>(&S))
2250       Name = GAS->getOutputName(i);
2251     TargetInfo::ConstraintInfo Info(S.getOutputConstraint(i), Name);
2252     bool IsValid = getTarget().validateOutputConstraint(Info); (void)IsValid;
2253     assert(IsValid && "Failed to parse output constraint");
2254     OutputConstraintInfos.push_back(Info);
2255   }
2256 
2257   for (unsigned i = 0, e = S.getNumInputs(); i != e; i++) {
2258     StringRef Name;
2259     if (const GCCAsmStmt *GAS = dyn_cast<GCCAsmStmt>(&S))
2260       Name = GAS->getInputName(i);
2261     TargetInfo::ConstraintInfo Info(S.getInputConstraint(i), Name);
2262     bool IsValid =
2263       getTarget().validateInputConstraint(OutputConstraintInfos, Info);
2264     assert(IsValid && "Failed to parse input constraint"); (void)IsValid;
2265     InputConstraintInfos.push_back(Info);
2266   }
2267 
2268   std::string Constraints;
2269 
2270   std::vector<LValue> ResultRegDests;
2271   std::vector<QualType> ResultRegQualTys;
2272   std::vector<llvm::Type *> ResultRegTypes;
2273   std::vector<llvm::Type *> ResultTruncRegTypes;
2274   std::vector<llvm::Type *> ArgTypes;
2275   std::vector<llvm::Value*> Args;
2276   llvm::BitVector ResultTypeRequiresCast;
2277 
2278   // Keep track of inout constraints.
2279   std::string InOutConstraints;
2280   std::vector<llvm::Value*> InOutArgs;
2281   std::vector<llvm::Type*> InOutArgTypes;
2282 
2283   // Keep track of out constraints for tied input operand.
2284   std::vector<std::string> OutputConstraints;
2285 
2286   // Keep track of defined physregs.
2287   llvm::SmallSet<std::string, 8> PhysRegOutputs;
2288 
2289   // An inline asm can be marked readonly if it meets the following conditions:
2290   //  - it doesn't have any sideeffects
2291   //  - it doesn't clobber memory
2292   //  - it doesn't return a value by-reference
2293   // It can be marked readnone if it doesn't have any input memory constraints
2294   // in addition to meeting the conditions listed above.
2295   bool ReadOnly = true, ReadNone = true;
2296 
2297   for (unsigned i = 0, e = S.getNumOutputs(); i != e; i++) {
2298     TargetInfo::ConstraintInfo &Info = OutputConstraintInfos[i];
2299 
2300     // Simplify the output constraint.
2301     std::string OutputConstraint(S.getOutputConstraint(i));
2302     OutputConstraint = SimplifyConstraint(OutputConstraint.c_str() + 1,
2303                                           getTarget(), &OutputConstraintInfos);
2304 
2305     const Expr *OutExpr = S.getOutputExpr(i);
2306     OutExpr = OutExpr->IgnoreParenNoopCasts(getContext());
2307 
2308     std::string GCCReg;
2309     OutputConstraint = AddVariableConstraints(OutputConstraint, *OutExpr,
2310                                               getTarget(), CGM, S,
2311                                               Info.earlyClobber(),
2312                                               &GCCReg);
2313     // Give an error on multiple outputs to same physreg.
2314     if (!GCCReg.empty() && !PhysRegOutputs.insert(GCCReg).second)
2315       CGM.Error(S.getAsmLoc(), "multiple outputs to hard register: " + GCCReg);
2316 
2317     OutputConstraints.push_back(OutputConstraint);
2318     LValue Dest = EmitLValue(OutExpr);
2319     if (!Constraints.empty())
2320       Constraints += ',';
2321 
2322     // If this is a register output, then make the inline asm return it
2323     // by-value.  If this is a memory result, return the value by-reference.
2324     QualType QTy = OutExpr->getType();
2325     const bool IsScalarOrAggregate = hasScalarEvaluationKind(QTy) ||
2326                                      hasAggregateEvaluationKind(QTy);
2327     if (!Info.allowsMemory() && IsScalarOrAggregate) {
2328 
2329       Constraints += "=" + OutputConstraint;
2330       ResultRegQualTys.push_back(QTy);
2331       ResultRegDests.push_back(Dest);
2332 
2333       llvm::Type *Ty = ConvertTypeForMem(QTy);
2334       const bool RequiresCast = Info.allowsRegister() &&
2335           (getTargetHooks().isScalarizableAsmOperand(*this, Ty) ||
2336            Ty->isAggregateType());
2337 
2338       ResultTruncRegTypes.push_back(Ty);
2339       ResultTypeRequiresCast.push_back(RequiresCast);
2340 
2341       if (RequiresCast) {
2342         unsigned Size = getContext().getTypeSize(QTy);
2343         Ty = llvm::IntegerType::get(getLLVMContext(), Size);
2344       }
2345       ResultRegTypes.push_back(Ty);
2346       // If this output is tied to an input, and if the input is larger, then
2347       // we need to set the actual result type of the inline asm node to be the
2348       // same as the input type.
2349       if (Info.hasMatchingInput()) {
2350         unsigned InputNo;
2351         for (InputNo = 0; InputNo != S.getNumInputs(); ++InputNo) {
2352           TargetInfo::ConstraintInfo &Input = InputConstraintInfos[InputNo];
2353           if (Input.hasTiedOperand() && Input.getTiedOperand() == i)
2354             break;
2355         }
2356         assert(InputNo != S.getNumInputs() && "Didn't find matching input!");
2357 
2358         QualType InputTy = S.getInputExpr(InputNo)->getType();
2359         QualType OutputType = OutExpr->getType();
2360 
2361         uint64_t InputSize = getContext().getTypeSize(InputTy);
2362         if (getContext().getTypeSize(OutputType) < InputSize) {
2363           // Form the asm to return the value as a larger integer or fp type.
2364           ResultRegTypes.back() = ConvertType(InputTy);
2365         }
2366       }
2367       if (llvm::Type* AdjTy =
2368             getTargetHooks().adjustInlineAsmType(*this, OutputConstraint,
2369                                                  ResultRegTypes.back()))
2370         ResultRegTypes.back() = AdjTy;
2371       else {
2372         CGM.getDiags().Report(S.getAsmLoc(),
2373                               diag::err_asm_invalid_type_in_input)
2374             << OutExpr->getType() << OutputConstraint;
2375       }
2376 
2377       // Update largest vector width for any vector types.
2378       if (auto *VT = dyn_cast<llvm::VectorType>(ResultRegTypes.back()))
2379         LargestVectorWidth =
2380             std::max((uint64_t)LargestVectorWidth,
2381                      VT->getPrimitiveSizeInBits().getKnownMinSize());
2382     } else {
2383       llvm::Type *DestAddrTy = Dest.getAddress(*this).getType();
2384       llvm::Value *DestPtr = Dest.getPointer(*this);
2385       // Matrix types in memory are represented by arrays, but accessed through
2386       // vector pointers, with the alignment specified on the access operation.
2387       // For inline assembly, update pointer arguments to use vector pointers.
2388       // Otherwise there will be a mis-match if the matrix is also an
2389       // input-argument which is represented as vector.
2390       if (isa<MatrixType>(OutExpr->getType().getCanonicalType())) {
2391         DestAddrTy = llvm::PointerType::get(
2392             ConvertType(OutExpr->getType()),
2393             cast<llvm::PointerType>(DestAddrTy)->getAddressSpace());
2394         DestPtr = Builder.CreateBitCast(DestPtr, DestAddrTy);
2395       }
2396       ArgTypes.push_back(DestAddrTy);
2397       Args.push_back(DestPtr);
2398       Constraints += "=*";
2399       Constraints += OutputConstraint;
2400       ReadOnly = ReadNone = false;
2401     }
2402 
2403     if (Info.isReadWrite()) {
2404       InOutConstraints += ',';
2405 
2406       const Expr *InputExpr = S.getOutputExpr(i);
2407       llvm::Value *Arg = EmitAsmInputLValue(Info, Dest, InputExpr->getType(),
2408                                             InOutConstraints,
2409                                             InputExpr->getExprLoc());
2410 
2411       if (llvm::Type* AdjTy =
2412           getTargetHooks().adjustInlineAsmType(*this, OutputConstraint,
2413                                                Arg->getType()))
2414         Arg = Builder.CreateBitCast(Arg, AdjTy);
2415 
2416       // Update largest vector width for any vector types.
2417       if (auto *VT = dyn_cast<llvm::VectorType>(Arg->getType()))
2418         LargestVectorWidth =
2419             std::max((uint64_t)LargestVectorWidth,
2420                      VT->getPrimitiveSizeInBits().getKnownMinSize());
2421       // Only tie earlyclobber physregs.
2422       if (Info.allowsRegister() && (GCCReg.empty() || Info.earlyClobber()))
2423         InOutConstraints += llvm::utostr(i);
2424       else
2425         InOutConstraints += OutputConstraint;
2426 
2427       InOutArgTypes.push_back(Arg->getType());
2428       InOutArgs.push_back(Arg);
2429     }
2430   }
2431 
2432   // If this is a Microsoft-style asm blob, store the return registers (EAX:EDX)
2433   // to the return value slot. Only do this when returning in registers.
2434   if (isa<MSAsmStmt>(&S)) {
2435     const ABIArgInfo &RetAI = CurFnInfo->getReturnInfo();
2436     if (RetAI.isDirect() || RetAI.isExtend()) {
2437       // Make a fake lvalue for the return value slot.
2438       LValue ReturnSlot = MakeAddrLValue(ReturnValue, FnRetTy);
2439       CGM.getTargetCodeGenInfo().addReturnRegisterOutputs(
2440           *this, ReturnSlot, Constraints, ResultRegTypes, ResultTruncRegTypes,
2441           ResultRegDests, AsmString, S.getNumOutputs());
2442       SawAsmBlock = true;
2443     }
2444   }
2445 
2446   for (unsigned i = 0, e = S.getNumInputs(); i != e; i++) {
2447     const Expr *InputExpr = S.getInputExpr(i);
2448 
2449     TargetInfo::ConstraintInfo &Info = InputConstraintInfos[i];
2450 
2451     if (Info.allowsMemory())
2452       ReadNone = false;
2453 
2454     if (!Constraints.empty())
2455       Constraints += ',';
2456 
2457     // Simplify the input constraint.
2458     std::string InputConstraint(S.getInputConstraint(i));
2459     InputConstraint = SimplifyConstraint(InputConstraint.c_str(), getTarget(),
2460                                          &OutputConstraintInfos);
2461 
2462     InputConstraint = AddVariableConstraints(
2463         InputConstraint, *InputExpr->IgnoreParenNoopCasts(getContext()),
2464         getTarget(), CGM, S, false /* No EarlyClobber */);
2465 
2466     std::string ReplaceConstraint (InputConstraint);
2467     llvm::Value *Arg = EmitAsmInput(Info, InputExpr, Constraints);
2468 
2469     // If this input argument is tied to a larger output result, extend the
2470     // input to be the same size as the output.  The LLVM backend wants to see
2471     // the input and output of a matching constraint be the same size.  Note
2472     // that GCC does not define what the top bits are here.  We use zext because
2473     // that is usually cheaper, but LLVM IR should really get an anyext someday.
2474     if (Info.hasTiedOperand()) {
2475       unsigned Output = Info.getTiedOperand();
2476       QualType OutputType = S.getOutputExpr(Output)->getType();
2477       QualType InputTy = InputExpr->getType();
2478 
2479       if (getContext().getTypeSize(OutputType) >
2480           getContext().getTypeSize(InputTy)) {
2481         // Use ptrtoint as appropriate so that we can do our extension.
2482         if (isa<llvm::PointerType>(Arg->getType()))
2483           Arg = Builder.CreatePtrToInt(Arg, IntPtrTy);
2484         llvm::Type *OutputTy = ConvertType(OutputType);
2485         if (isa<llvm::IntegerType>(OutputTy))
2486           Arg = Builder.CreateZExt(Arg, OutputTy);
2487         else if (isa<llvm::PointerType>(OutputTy))
2488           Arg = Builder.CreateZExt(Arg, IntPtrTy);
2489         else {
2490           assert(OutputTy->isFloatingPointTy() && "Unexpected output type");
2491           Arg = Builder.CreateFPExt(Arg, OutputTy);
2492         }
2493       }
2494       // Deal with the tied operands' constraint code in adjustInlineAsmType.
2495       ReplaceConstraint = OutputConstraints[Output];
2496     }
2497     if (llvm::Type* AdjTy =
2498           getTargetHooks().adjustInlineAsmType(*this, ReplaceConstraint,
2499                                                    Arg->getType()))
2500       Arg = Builder.CreateBitCast(Arg, AdjTy);
2501     else
2502       CGM.getDiags().Report(S.getAsmLoc(), diag::err_asm_invalid_type_in_input)
2503           << InputExpr->getType() << InputConstraint;
2504 
2505     // Update largest vector width for any vector types.
2506     if (auto *VT = dyn_cast<llvm::VectorType>(Arg->getType()))
2507       LargestVectorWidth =
2508           std::max((uint64_t)LargestVectorWidth,
2509                    VT->getPrimitiveSizeInBits().getKnownMinSize());
2510 
2511     ArgTypes.push_back(Arg->getType());
2512     Args.push_back(Arg);
2513     Constraints += InputConstraint;
2514   }
2515 
2516   // Labels
2517   SmallVector<llvm::BasicBlock *, 16> Transfer;
2518   llvm::BasicBlock *Fallthrough = nullptr;
2519   bool IsGCCAsmGoto = false;
2520   if (const auto *GS =  dyn_cast<GCCAsmStmt>(&S)) {
2521     IsGCCAsmGoto = GS->isAsmGoto();
2522     if (IsGCCAsmGoto) {
2523       for (const auto *E : GS->labels()) {
2524         JumpDest Dest = getJumpDestForLabel(E->getLabel());
2525         Transfer.push_back(Dest.getBlock());
2526         llvm::BlockAddress *BA =
2527             llvm::BlockAddress::get(CurFn, Dest.getBlock());
2528         Args.push_back(BA);
2529         ArgTypes.push_back(BA->getType());
2530         if (!Constraints.empty())
2531           Constraints += ',';
2532         Constraints += 'X';
2533       }
2534       Fallthrough = createBasicBlock("asm.fallthrough");
2535     }
2536   }
2537 
2538   // Append the "input" part of inout constraints last.
2539   for (unsigned i = 0, e = InOutArgs.size(); i != e; i++) {
2540     ArgTypes.push_back(InOutArgTypes[i]);
2541     Args.push_back(InOutArgs[i]);
2542   }
2543   Constraints += InOutConstraints;
2544 
2545   bool HasUnwindClobber = false;
2546 
2547   // Clobbers
2548   for (unsigned i = 0, e = S.getNumClobbers(); i != e; i++) {
2549     StringRef Clobber = S.getClobber(i);
2550 
2551     if (Clobber == "memory")
2552       ReadOnly = ReadNone = false;
2553     else if (Clobber == "unwind") {
2554       HasUnwindClobber = true;
2555       continue;
2556     } else if (Clobber != "cc") {
2557       Clobber = getTarget().getNormalizedGCCRegisterName(Clobber);
2558       if (CGM.getCodeGenOpts().StackClashProtector &&
2559           getTarget().isSPRegName(Clobber)) {
2560         CGM.getDiags().Report(S.getAsmLoc(),
2561                               diag::warn_stack_clash_protection_inline_asm);
2562       }
2563     }
2564 
2565     if (isa<MSAsmStmt>(&S)) {
2566       if (Clobber == "eax" || Clobber == "edx") {
2567         if (Constraints.find("=&A") != std::string::npos)
2568           continue;
2569         std::string::size_type position1 =
2570             Constraints.find("={" + Clobber.str() + "}");
2571         if (position1 != std::string::npos) {
2572           Constraints.insert(position1 + 1, "&");
2573           continue;
2574         }
2575         std::string::size_type position2 = Constraints.find("=A");
2576         if (position2 != std::string::npos) {
2577           Constraints.insert(position2 + 1, "&");
2578           continue;
2579         }
2580       }
2581     }
2582     if (!Constraints.empty())
2583       Constraints += ',';
2584 
2585     Constraints += "~{";
2586     Constraints += Clobber;
2587     Constraints += '}';
2588   }
2589 
2590   assert(!(HasUnwindClobber && IsGCCAsmGoto) &&
2591          "unwind clobber can't be used with asm goto");
2592 
2593   // Add machine specific clobbers
2594   std::string MachineClobbers = getTarget().getClobbers();
2595   if (!MachineClobbers.empty()) {
2596     if (!Constraints.empty())
2597       Constraints += ',';
2598     Constraints += MachineClobbers;
2599   }
2600 
2601   llvm::Type *ResultType;
2602   if (ResultRegTypes.empty())
2603     ResultType = VoidTy;
2604   else if (ResultRegTypes.size() == 1)
2605     ResultType = ResultRegTypes[0];
2606   else
2607     ResultType = llvm::StructType::get(getLLVMContext(), ResultRegTypes);
2608 
2609   llvm::FunctionType *FTy =
2610     llvm::FunctionType::get(ResultType, ArgTypes, false);
2611 
2612   bool HasSideEffect = S.isVolatile() || S.getNumOutputs() == 0;
2613   llvm::InlineAsm::AsmDialect AsmDialect = isa<MSAsmStmt>(&S) ?
2614     llvm::InlineAsm::AD_Intel : llvm::InlineAsm::AD_ATT;
2615   llvm::InlineAsm *IA = llvm::InlineAsm::get(
2616       FTy, AsmString, Constraints, HasSideEffect,
2617       /* IsAlignStack */ false, AsmDialect, HasUnwindClobber);
2618   std::vector<llvm::Value*> RegResults;
2619   if (IsGCCAsmGoto) {
2620     llvm::CallBrInst *Result =
2621         Builder.CreateCallBr(IA, Fallthrough, Transfer, Args);
2622     EmitBlock(Fallthrough);
2623     UpdateAsmCallInst(cast<llvm::CallBase>(*Result), HasSideEffect, false,
2624                       ReadOnly, ReadNone, InNoMergeAttributedStmt, S,
2625                       ResultRegTypes, *this, RegResults);
2626   } else if (HasUnwindClobber) {
2627     llvm::CallBase *Result = EmitCallOrInvoke(IA, Args, "");
2628     UpdateAsmCallInst(*Result, HasSideEffect, true, ReadOnly, ReadNone,
2629                       InNoMergeAttributedStmt, S, ResultRegTypes, *this,
2630                       RegResults);
2631   } else {
2632     llvm::CallInst *Result =
2633         Builder.CreateCall(IA, Args, getBundlesForFunclet(IA));
2634     UpdateAsmCallInst(cast<llvm::CallBase>(*Result), HasSideEffect, false,
2635                       ReadOnly, ReadNone, InNoMergeAttributedStmt, S,
2636                       ResultRegTypes, *this, RegResults);
2637   }
2638 
2639   assert(RegResults.size() == ResultRegTypes.size());
2640   assert(RegResults.size() == ResultTruncRegTypes.size());
2641   assert(RegResults.size() == ResultRegDests.size());
2642   // ResultRegDests can be also populated by addReturnRegisterOutputs() above,
2643   // in which case its size may grow.
2644   assert(ResultTypeRequiresCast.size() <= ResultRegDests.size());
2645   for (unsigned i = 0, e = RegResults.size(); i != e; ++i) {
2646     llvm::Value *Tmp = RegResults[i];
2647     llvm::Type *TruncTy = ResultTruncRegTypes[i];
2648 
2649     // If the result type of the LLVM IR asm doesn't match the result type of
2650     // the expression, do the conversion.
2651     if (ResultRegTypes[i] != ResultTruncRegTypes[i]) {
2652 
2653       // Truncate the integer result to the right size, note that TruncTy can be
2654       // a pointer.
2655       if (TruncTy->isFloatingPointTy())
2656         Tmp = Builder.CreateFPTrunc(Tmp, TruncTy);
2657       else if (TruncTy->isPointerTy() && Tmp->getType()->isIntegerTy()) {
2658         uint64_t ResSize = CGM.getDataLayout().getTypeSizeInBits(TruncTy);
2659         Tmp = Builder.CreateTrunc(Tmp,
2660                    llvm::IntegerType::get(getLLVMContext(), (unsigned)ResSize));
2661         Tmp = Builder.CreateIntToPtr(Tmp, TruncTy);
2662       } else if (Tmp->getType()->isPointerTy() && TruncTy->isIntegerTy()) {
2663         uint64_t TmpSize =CGM.getDataLayout().getTypeSizeInBits(Tmp->getType());
2664         Tmp = Builder.CreatePtrToInt(Tmp,
2665                    llvm::IntegerType::get(getLLVMContext(), (unsigned)TmpSize));
2666         Tmp = Builder.CreateTrunc(Tmp, TruncTy);
2667       } else if (TruncTy->isIntegerTy()) {
2668         Tmp = Builder.CreateZExtOrTrunc(Tmp, TruncTy);
2669       } else if (TruncTy->isVectorTy()) {
2670         Tmp = Builder.CreateBitCast(Tmp, TruncTy);
2671       }
2672     }
2673 
2674     LValue Dest = ResultRegDests[i];
2675     // ResultTypeRequiresCast elements correspond to the first
2676     // ResultTypeRequiresCast.size() elements of RegResults.
2677     if ((i < ResultTypeRequiresCast.size()) && ResultTypeRequiresCast[i]) {
2678       unsigned Size = getContext().getTypeSize(ResultRegQualTys[i]);
2679       Address A = Builder.CreateBitCast(Dest.getAddress(*this),
2680                                         ResultRegTypes[i]->getPointerTo());
2681       if (getTargetHooks().isScalarizableAsmOperand(*this, TruncTy)) {
2682         Builder.CreateStore(Tmp, A);
2683         continue;
2684       }
2685 
2686       QualType Ty = getContext().getIntTypeForBitwidth(Size, /*Signed*/ false);
2687       if (Ty.isNull()) {
2688         const Expr *OutExpr = S.getOutputExpr(i);
2689         CGM.Error(
2690             OutExpr->getExprLoc(),
2691             "impossible constraint in asm: can't store value into a register");
2692         return;
2693       }
2694       Dest = MakeAddrLValue(A, Ty);
2695     }
2696     EmitStoreThroughLValue(RValue::get(Tmp), Dest);
2697   }
2698 }
2699 
InitCapturedStruct(const CapturedStmt & S)2700 LValue CodeGenFunction::InitCapturedStruct(const CapturedStmt &S) {
2701   const RecordDecl *RD = S.getCapturedRecordDecl();
2702   QualType RecordTy = getContext().getRecordType(RD);
2703 
2704   // Initialize the captured struct.
2705   LValue SlotLV =
2706     MakeAddrLValue(CreateMemTemp(RecordTy, "agg.captured"), RecordTy);
2707 
2708   RecordDecl::field_iterator CurField = RD->field_begin();
2709   for (CapturedStmt::const_capture_init_iterator I = S.capture_init_begin(),
2710                                                  E = S.capture_init_end();
2711        I != E; ++I, ++CurField) {
2712     LValue LV = EmitLValueForFieldInitialization(SlotLV, *CurField);
2713     if (CurField->hasCapturedVLAType()) {
2714       EmitLambdaVLACapture(CurField->getCapturedVLAType(), LV);
2715     } else {
2716       EmitInitializerForField(*CurField, LV, *I);
2717     }
2718   }
2719 
2720   return SlotLV;
2721 }
2722 
2723 /// Generate an outlined function for the body of a CapturedStmt, store any
2724 /// captured variables into the captured struct, and call the outlined function.
2725 llvm::Function *
EmitCapturedStmt(const CapturedStmt & S,CapturedRegionKind K)2726 CodeGenFunction::EmitCapturedStmt(const CapturedStmt &S, CapturedRegionKind K) {
2727   LValue CapStruct = InitCapturedStruct(S);
2728 
2729   // Emit the CapturedDecl
2730   CodeGenFunction CGF(CGM, true);
2731   CGCapturedStmtRAII CapInfoRAII(CGF, new CGCapturedStmtInfo(S, K));
2732   llvm::Function *F = CGF.GenerateCapturedStmtFunction(S);
2733   delete CGF.CapturedStmtInfo;
2734 
2735   // Emit call to the helper function.
2736   EmitCallOrInvoke(F, CapStruct.getPointer(*this));
2737 
2738   return F;
2739 }
2740 
GenerateCapturedStmtArgument(const CapturedStmt & S)2741 Address CodeGenFunction::GenerateCapturedStmtArgument(const CapturedStmt &S) {
2742   LValue CapStruct = InitCapturedStruct(S);
2743   return CapStruct.getAddress(*this);
2744 }
2745 
2746 /// Creates the outlined function for a CapturedStmt.
2747 llvm::Function *
GenerateCapturedStmtFunction(const CapturedStmt & S)2748 CodeGenFunction::GenerateCapturedStmtFunction(const CapturedStmt &S) {
2749   assert(CapturedStmtInfo &&
2750     "CapturedStmtInfo should be set when generating the captured function");
2751   const CapturedDecl *CD = S.getCapturedDecl();
2752   const RecordDecl *RD = S.getCapturedRecordDecl();
2753   SourceLocation Loc = S.getBeginLoc();
2754   assert(CD->hasBody() && "missing CapturedDecl body");
2755 
2756   // Build the argument list.
2757   ASTContext &Ctx = CGM.getContext();
2758   FunctionArgList Args;
2759   Args.append(CD->param_begin(), CD->param_end());
2760 
2761   // Create the function declaration.
2762   const CGFunctionInfo &FuncInfo =
2763     CGM.getTypes().arrangeBuiltinFunctionDeclaration(Ctx.VoidTy, Args);
2764   llvm::FunctionType *FuncLLVMTy = CGM.getTypes().GetFunctionType(FuncInfo);
2765 
2766   llvm::Function *F =
2767     llvm::Function::Create(FuncLLVMTy, llvm::GlobalValue::InternalLinkage,
2768                            CapturedStmtInfo->getHelperName(), &CGM.getModule());
2769   CGM.SetInternalFunctionAttributes(CD, F, FuncInfo);
2770   if (CD->isNothrow())
2771     F->addFnAttr(llvm::Attribute::NoUnwind);
2772 
2773   // Generate the function.
2774   StartFunction(CD, Ctx.VoidTy, F, FuncInfo, Args, CD->getLocation(),
2775                 CD->getBody()->getBeginLoc());
2776   // Set the context parameter in CapturedStmtInfo.
2777   Address DeclPtr = GetAddrOfLocalVar(CD->getContextParam());
2778   CapturedStmtInfo->setContextValue(Builder.CreateLoad(DeclPtr));
2779 
2780   // Initialize variable-length arrays.
2781   LValue Base = MakeNaturalAlignAddrLValue(CapturedStmtInfo->getContextValue(),
2782                                            Ctx.getTagDeclType(RD));
2783   for (auto *FD : RD->fields()) {
2784     if (FD->hasCapturedVLAType()) {
2785       auto *ExprArg =
2786           EmitLoadOfLValue(EmitLValueForField(Base, FD), S.getBeginLoc())
2787               .getScalarVal();
2788       auto VAT = FD->getCapturedVLAType();
2789       VLASizeMap[VAT->getSizeExpr()] = ExprArg;
2790     }
2791   }
2792 
2793   // If 'this' is captured, load it into CXXThisValue.
2794   if (CapturedStmtInfo->isCXXThisExprCaptured()) {
2795     FieldDecl *FD = CapturedStmtInfo->getThisFieldDecl();
2796     LValue ThisLValue = EmitLValueForField(Base, FD);
2797     CXXThisValue = EmitLoadOfLValue(ThisLValue, Loc).getScalarVal();
2798   }
2799 
2800   PGO.assignRegionCounters(GlobalDecl(CD), F);
2801   CapturedStmtInfo->EmitBody(*this, CD->getBody());
2802   FinishFunction(CD->getBodyRBrace());
2803 
2804   return F;
2805 }
2806