[analyzer] Ensure BugReporterTracking works on regions with pointer arithmetic

Introduce a new helper function, which computes the first symbolic region in
the base region chain. The corresponding symbol has been used for assuming that
a pointer is null. Now, it will also be used for checking if it is null.

This ensures that we are tracking a null pointer correctly in the BugReporter.

llvm-svn: 179916

1 files changed, 8 insertions, 13 deletions

diff --git a/clang/lib/StaticAnalyzer/Core/SimpleConstraintManager.cpp b/clang/lib/StaticAnalyzer/Core/SimpleConstraintManager.cpp
index 34de3453ca3..a06268dd331 100644
--- a/clang/lib/StaticAnalyzer/Core/SimpleConstraintManager.cpp
+++ b/clang/lib/StaticAnalyzer/Core/SimpleConstraintManager.cpp
@@ -90,20 +90,15 @@ ProgramStateRef SimpleConstraintManager::assumeAux(ProgramStateRef state,
 
   case loc::MemRegionKind: {
     // FIXME: Should this go into the storemanager?
-
     const MemRegion *R = Cond.castAs<loc::MemRegionVal>().getRegion();
-    const SubRegion *SubR = dyn_cast<SubRegion>(R);
-
-    while (SubR) {
-      // FIXME: now we only find the first symbolic region.
-      if (const SymbolicRegion *SymR = dyn_cast<SymbolicRegion>(SubR)) {
-        const llvm::APSInt &zero = getBasicVals().getZeroWithPtrWidth();
-        if (Assumption)
-          return assumeSymNE(state, SymR->getSymbol(), zero, zero);
-        else
-          return assumeSymEQ(state, SymR->getSymbol(), zero, zero);
-      }
-      SubR = dyn_cast<SubRegion>(SubR->getSuperRegion());
+
+    // FIXME: now we only find the first symbolic region.
+    if (const SymbolicRegion *SymR = R->getSymbolicBase()) {
+      const llvm::APSInt &zero = getBasicVals().getZeroWithPtrWidth();
+      if (Assumption)
+        return assumeSymNE(state, SymR->getSymbol(), zero, zero);
+      else
+        return assumeSymEQ(state, SymR->getSymbol(), zero, zero);
     }
 
     // FALL-THROUGH.