[analyzer] Include block capture copy expressions in the CFG.

This prevents spurious dead store warnings when a C++ lambda is casted to a block.

I've also added several tests documenting our still-incomplete support for lambda-to-block
casts.

rdar://problem/22236293

llvm-svn: 254107

1 files changed, 14 insertions, 1 deletions

diff --git a/clang/lib/Analysis/CFG.cpp b/clang/lib/Analysis/CFG.cpp
index fba9a41f232..cff15cb3fd8 100644
--- a/clang/lib/Analysis/CFG.cpp
+++ b/clang/lib/Analysis/CFG.cpp
@@ -460,6 +460,7 @@ private:
   CFGBlock *VisitImplicitCastExpr(ImplicitCastExpr *E, AddStmtChoice asc);
   CFGBlock *VisitIndirectGotoStmt(IndirectGotoStmt *I);
   CFGBlock *VisitLabelStmt(LabelStmt *L);
+  CFGBlock *VisitBlockExpr(BlockExpr *E, AddStmtChoice asc);
   CFGBlock *VisitLambdaExpr(LambdaExpr *E, AddStmtChoice asc);
   CFGBlock *VisitLogicalOperator(BinaryOperator *B);
   std::pair<CFGBlock *, CFGBlock *> VisitLogicalOperator(BinaryOperator *B,
@@ -1453,7 +1454,7 @@ CFGBlock *CFGBuilder::Visit(Stmt * S, AddStmtChoice asc) {
       return VisitBinaryOperator(cast<BinaryOperator>(S), asc);
 
     case Stmt::BlockExprClass:
-      return VisitNoRecurse(cast<Expr>(S), asc);
+      return VisitBlockExpr(cast<BlockExpr>(S), asc);
 
     case Stmt::BreakStmtClass:
       return VisitBreakStmt(cast<BreakStmt>(S));
@@ -2333,6 +2334,18 @@ CFGBlock *CFGBuilder::VisitLabelStmt(LabelStmt *L) {
   return LabelBlock;
 }
 
+CFGBlock *CFGBuilder::VisitBlockExpr(BlockExpr *E, AddStmtChoice asc) {
+  CFGBlock *LastBlock = VisitNoRecurse(E, asc);
+  for (const BlockDecl::Capture &CI : E->getBlockDecl()->captures()) {
+    if (Expr *CopyExpr = CI.getCopyExpr()) {
+      CFGBlock *Tmp = Visit(CopyExpr);
+      if (Tmp)
+        LastBlock = Tmp;
+    }
+  }
+  return LastBlock;
+}
+
 CFGBlock *CFGBuilder::VisitLambdaExpr(LambdaExpr *E, AddStmtChoice asc) {
   CFGBlock *LastBlock = VisitNoRecurse(E, asc);
   for (LambdaExpr::capture_init_iterator it = E->capture_init_begin(),