Allow 'Environment::getSVal()' to allow an optional way for checkers to do a direct lookup to values bound to expressions, without
resulting to lazy logic.  This is critical for the OSAtomicChecker that does a simulated load on any arbitrary expression.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@130292 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/StaticAnalyzer/Checkers/OSAtomicChecker.cpp b/lib/StaticAnalyzer/Checkers/OSAtomicChecker.cpp
index 6a4f192..7262bc3 100644
--- a/lib/StaticAnalyzer/Checkers/OSAtomicChecker.cpp
+++ b/lib/StaticAnalyzer/Checkers/OSAtomicChecker.cpp
@@ -127,7 +127,12 @@
 
     ExplodedNode *N = *I;
     const GRState *stateLoad = N->getState();
-    SVal theValueVal_untested = stateLoad->getSVal(theValueExpr);
+
+    // Use direct bindings from the environment since we are forcing a load
+    // from a location that the Environment would typically not be used
+    // to bind a value.
+    SVal theValueVal_untested = stateLoad->getSVal(theValueExpr, true);
+
     SVal oldValueVal_untested = stateLoad->getSVal(oldValueExpr);
 
     // FIXME: Issue an error.
diff --git a/lib/StaticAnalyzer/Core/Environment.cpp b/lib/StaticAnalyzer/Core/Environment.cpp
index 0d43c37..a00f9dc 100644
--- a/lib/StaticAnalyzer/Core/Environment.cpp
+++ b/lib/StaticAnalyzer/Core/Environment.cpp
@@ -27,7 +27,17 @@
   return UnknownVal();
 }
 
-SVal Environment::getSVal(const Stmt *E, SValBuilder& svalBuilder) const {
+SVal Environment::getSVal(const Stmt *E, SValBuilder& svalBuilder,
+			  bool useOnlyDirectBindings) const {
+
+  if (useOnlyDirectBindings) {
+    // This branch is rarely taken, but can be exercised by
+    // checkers that explicitly bind values to arbitrary
+    // expressions.  It is crucial that we do not ignore any
+    // expression here, and do a direct lookup.
+    return lookupExpr(E);
+  }
+
   for (;;) {
     switch (E->getStmtClass()) {
       case Stmt::AddrLabelExprClass: