[CFG]

After discussion with Zhongxing, don't force the initializer of DeclStmts to be
block-level expressions.

This led to some interesting fallout:

[UninitializedValues]

Always visit the initializer of DeclStmts (do not assume they are block-level expressions).

[BasicStore]

With initializers of DeclStmts no longer block-level expressions, this causes self-referencing initializers (e.g. 'int x = x') to no longer cause the initialized variable to be live before the DeclStmt.  While this is correct, it caused BasicStore::RemoveDeadBindings() to prune off the values of these variables from the initial store (where they are set to uninitialized).  The fix is to back-port some (and only some) of the lazy-binding logic from RegionStore to
BasicStore.  Now the default values of local variables are determined lazily as opposed
to explicitly initialized.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@97591 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 6 insertions, 2 deletions

diff --git a/lib/Analysis/UninitializedValues.cpp b/lib/Analysis/UninitializedValues.cpp
index bdc0e7c621..7a628642dc 100644
--- a/lib/Analysis/UninitializedValues.cpp
+++ b/lib/Analysis/UninitializedValues.cpp
@@ -134,8 +134,12 @@ bool TransferFuncs::VisitDeclStmt(DeclStmt* S) {
   for (DeclStmt::decl_iterator I=S->decl_begin(), E=S->decl_end(); I!=E; ++I) {
     VarDecl *VD = dyn_cast<VarDecl>(*I);
     if (VD && VD->isBlockVarDecl()) {
-      if (Stmt* I = VD->getInit())
-        V(VD,AD) = AD.FullUninitTaint ? V(cast<Expr>(I),AD) : Initialized;
+      if (Stmt* I = VD->getInit()) {
+        // Visit the subexpression to check for uses of uninitialized values,
+        // even if we don't propagate that value.
+        bool isSubExprUninit = Visit(I);
+        V(VD,AD) = AD.FullUninitTaint ? isSubExprUninit : Initialized;
+      }
       else {
         // Special case for declarations of array types.  For things like:
         //