CFG: add all LHS of assingments as lvalue. This improves support for C++ reference. Patch by Jordy.

llvm-svn: 105383

2 files changed, 30 insertions, 2 deletions

diff --git a/clang/lib/Analysis/CFG.cpp b/clang/lib/Analysis/CFG.cpp
index 6f2cb41a6e4..1d294ae8eaf 100644
--- a/clang/lib/Analysis/CFG.cpp
+++ b/clang/lib/Analysis/CFG.cpp
@@ -538,6 +538,15 @@ CFGBlock *CFGBuilder::VisitBinaryOperator(BinaryOperator *B,
     addStmt(B->getRHS());
     return addStmt(B->getLHS());
   }
+  else if (B->isAssignmentOp()) {
+    if (asc.alwaysAdd()) {
+      autoCreateBlock();
+      AppendStmt(Block, B, asc);
+    }
+    
+    Visit(B->getRHS());
+    return Visit(B->getLHS(), AddStmtChoice::AsLValueNotAlwaysAdd);
+  }
 
   return VisitStmt(B, asc);
 }
@@ -612,8 +621,12 @@ CFGBlock *CFGBuilder::VisitCallExpr(CallExpr *C, AddStmtChoice asc) {
   if (!CanThrow(C->getCallee()))
     AddEHEdge = false;
 
-  if (!NoReturn && !AddEHEdge)
-    return VisitStmt(C, AddStmtChoice::AlwaysAdd);
+  if (!NoReturn && !AddEHEdge) {
+    if (asc.asLValue())
+      return VisitStmt(C, AddStmtChoice::AlwaysAddAsLValue);
+    else
+      return VisitStmt(C, AddStmtChoice::AlwaysAdd);
+  }
 
   if (Block) {
     Succ = Block;
diff --git a/clang/test/Analysis/reference.cpp b/clang/test/Analysis/reference.cpp
index 54d7cf57e0c..6b962157da7 100644
--- a/clang/test/Analysis/reference.cpp
+++ b/clang/test/Analysis/reference.cpp
@@ -9,3 +9,18 @@ void f1() {
   if (b != 3)
     *p = 1; // no-warning
 }
+
+char* ptr();
+char& ref();
+
+// These next two tests just shouldn't crash.
+char t1 () {
+  ref() = 'c';
+  return '0';
+}
+
+// just a sanity test, the same behavior as t1()
+char t2 () {
+  *ptr() = 'c';
+  return '0';
+}