Add PreVisitReturn to Malloc checker. Now we can recognize returned memory

block.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@89071 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 30 insertions, 4 deletions

diff --git a/lib/Analysis/MallocChecker.cpp b/lib/Analysis/MallocChecker.cpp
index fdd6a3d026..93e708332e 100644
--- a/lib/Analysis/MallocChecker.cpp
+++ b/lib/Analysis/MallocChecker.cpp
@@ -60,6 +60,7 @@ public:
   void PostVisitCallExpr(CheckerContext &C, const CallExpr *CE);
   void EvalDeadSymbols(CheckerContext &C,const Stmt *S,SymbolReaper &SymReaper);
   void EvalEndPath(GREndPathNodeBuilder &B, void *tag, GRExprEngine &Eng);
+  void PreVisitReturnStmt(CheckerContext &C, const ReturnStmt *S);
 private:
   void MallocMem(CheckerContext &C, const CallExpr *CE);
   void FreeMem(CheckerContext &C, const CallExpr *CE);
@@ -190,3 +191,28 @@ void MallocChecker::EvalEndPath(GREndPathNodeBuilder &B, void *tag,
     }
   }
 }
+
+void MallocChecker::PreVisitReturnStmt(CheckerContext &C, const ReturnStmt *S) {
+  const Expr *RetE = S->getRetValue();
+  if (!RetE)
+    return;
+
+  const GRState *state = C.getState();
+
+  SymbolRef Sym = state->getSVal(RetE).getAsSymbol();
+
+  if (!Sym)
+    return;
+
+  const RefState *RS = state->get<RegionState>(Sym);
+  if (!RS)
+    return;
+
+  // FIXME: check other cases.
+  if (RS->isAllocated())
+    state = state->set<RegionState>(Sym, RefState::getEscaped(S));
+
+  ExplodedNode *N = C.GenerateNode(S, state);
+  if (N)
+    C.addTransition(N);
+}
diff --git a/test/Analysis/malloc.c b/test/Analysis/malloc.c
index 3dc5843ae0..6a17cba349 100644
--- a/test/Analysis/malloc.c
+++ b/test/Analysis/malloc.c
@@ -23,8 +23,8 @@ void f2() {
 // or inter-procedural analysis, this is a conservative answer.
 int *f3() {
   static int *p = 0;
-  p = malloc(10); // will be fixed.
-  return p; // expected-warning{{Allocated memory never released. Potential memory leak.}}
+  p = malloc(10); 
+  return p; // no-warning
 }
 
 // This case tests that storing malloc'ed memory to a static global variable
@@ -32,6 +32,6 @@ int *f3() {
 // functions or inter-procedural analysis, this is a conservative answer.
 static int *p_f4 = 0;
 int *f4() {
-  p_f4 = malloc(10); // will be fixed.
-  return p_f4; // expected-warning{{Allocated memory never released. Potential memory leak.}}
+  p_f4 = malloc(10); 
+  return p_f4; // no-warning
 }