Fix: <rdar://problem/6740387>. Sending nil to an object that returns a struct

should only be an error if that value is consumed. This fix was largely
accomplished by moving 'isConsumedExpr' back to ParentMap.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@68195 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 3 insertions, 43 deletions

diff --git a/lib/Analysis/CheckDeadStores.cpp b/lib/Analysis/CheckDeadStores.cpp
index 504de3c97d..d1b3be511a 100644
--- a/lib/Analysis/CheckDeadStores.cpp
+++ b/lib/Analysis/CheckDeadStores.cpp
@@ -38,10 +38,7 @@ public:
     : Ctx(ctx), BR(br), Parents(parents) {}
   
   virtual ~DeadStoreObs() {}
-  
-  bool isConsumedExpr(Expr* E) const;
-  
-  
+
   void Report(VarDecl* V, DeadStoreKind dsk, SourceLocation L, SourceRange R) {
 
     std::string name = V->getNameAsString();
@@ -148,7 +145,7 @@ public:
               return;
             
           // Otherwise, issue a warning.
-          DeadStoreKind dsk = isConsumedExpr(B)
+          DeadStoreKind dsk = Parents.isConsumedExpr(B)
                               ? Enclosing 
                               : (isIncrement(VD,B) ? DeadIncrement : Standard);
           
@@ -163,7 +160,7 @@ public:
       //  about preincrements to dead variables when the preincrement occurs
       //  as a subexpression.  This can lead to false negatives, e.g. "(++x);"
       //  A generalized dead code checker should find such issues.
-      if (U->isPrefix() && isConsumedExpr(U))
+      if (U->isPrefix() && Parents.isConsumedExpr(U))
         return;
 
       Expr *Ex = U->getSubExpr()->IgnoreParenCasts();
@@ -218,43 +215,6 @@ public:
   
 } // end anonymous namespace
 
-bool DeadStoreObs::isConsumedExpr(Expr* E) const {
-  Stmt *P = Parents.getParent(E);
-  Stmt *DirectChild = E;
-  
-  // Ignore parents that are parentheses or casts.
-  while (P && (isa<ParenExpr>(E) || isa<CastExpr>(E))) {
-    DirectChild = P;
-    P = Parents.getParent(P);
-  }
-  
-  if (!P)
-    return false;
-  
-  switch (P->getStmtClass()) {
-    default:
-      return isa<Expr>(P);
-    case Stmt::BinaryOperatorClass: {
-      BinaryOperator *BE = cast<BinaryOperator>(P);
-      return BE->getOpcode()==BinaryOperator::Comma && DirectChild==BE->getLHS();
-    }
-    case Stmt::ForStmtClass:
-      return DirectChild == cast<ForStmt>(P)->getCond();
-    case Stmt::WhileStmtClass:
-      return DirectChild == cast<WhileStmt>(P)->getCond();      
-    case Stmt::DoStmtClass:
-      return DirectChild == cast<DoStmt>(P)->getCond();
-    case Stmt::IfStmtClass:
-      return DirectChild == cast<IfStmt>(P)->getCond();
-    case Stmt::IndirectGotoStmtClass:
-      return DirectChild == cast<IndirectGotoStmt>(P)->getTarget();
-    case Stmt::SwitchStmtClass:
-      return DirectChild == cast<SwitchStmt>(P)->getCond();
-    case Stmt::ReturnStmtClass:
-      return true;
-  }
-}
-
 //===----------------------------------------------------------------------===//
 // Driver function to invoke the Dead-Stores checker on a CFG.
 //===----------------------------------------------------------------------===//