[analyzer] Use Clang's evaluation for global constants and default arguments.

Previously, we were handling only simple integer constants for globals and
the smattering of implicitly-valued expressions handled by Environment for
default arguments. Now, we can use any integer constant expression that
Clang can evaluate, in addition to everything we handled before.

PR15094 / <rdar://problem/12830437>

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@175026 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 8 insertions, 5 deletions

diff --git a/lib/StaticAnalyzer/Core/RegionStore.cpp b/lib/StaticAnalyzer/Core/RegionStore.cpp
index 399f9ebae8..9572f64865 100644
--- a/lib/StaticAnalyzer/Core/RegionStore.cpp
+++ b/lib/StaticAnalyzer/Core/RegionStore.cpp
@@ -1524,11 +1524,14 @@ SVal RegionStoreManager::getBindingForVar(RegionBindingsConstRef B,
     QualType CT = Ctx.getCanonicalType(T);
     if (CT.isConstQualified()) {
       if (const Expr *Init = VD->getInit()) {
-        if (const IntegerLiteral *IL =
-            dyn_cast<IntegerLiteral>(Init->IgnoreParenCasts())) {
-          const nonloc::ConcreteInt &V = svalBuilder.makeIntVal(IL);
-          return svalBuilder.evalCast(V, Init->getType(), IL->getType());
-        }
+        llvm::APSInt Result;
+        if (Init->EvaluateAsInt(Result, Ctx))
+          return svalBuilder.makeIntVal(Result);
+
+        if (Init->isNullPointerConstant(Ctx, Expr::NPC_ValueDependentIsNotNull))
+          return svalBuilder.makeNull();
+
+        // FIXME: Handle other possible constant expressions.
       }
     }