[analyzer] Handle C string default values for const char * arguments.

Previously, SValBuilder knew how to evaluate StringLiterals, but couldn't
handle an array-to-pointer decay for constant values. Additionally,
RegionStore was being too strict about loading from an array, refusing to
return a 'char' value from a 'const char' array. Both of these have been
fixed.

llvm-svn: 186520

1 files changed, 11 insertions, 0 deletions

diff --git a/clang/lib/StaticAnalyzer/Core/SValBuilder.cpp b/clang/lib/StaticAnalyzer/Core/SValBuilder.cpp
index ecfceaa0f3c..1992abbf4c3 100644
--- a/clang/lib/StaticAnalyzer/Core/SValBuilder.cpp
+++ b/clang/lib/StaticAnalyzer/Core/SValBuilder.cpp
@@ -266,6 +266,17 @@ Optional<SVal> SValBuilder::getConstantVal(const Expr *E) {
   case Stmt::CXXNullPtrLiteralExprClass:
     return makeNull();
 
+  case Stmt::ImplicitCastExprClass: {
+    const CastExpr *CE = cast<CastExpr>(E);
+    if (CE->getCastKind() == CK_ArrayToPointerDecay) {
+      Optional<SVal> ArrayVal = getConstantVal(CE->getSubExpr());
+      if (!ArrayVal)
+        return None;
+      return evalCast(*ArrayVal, CE->getType(), CE->getSubExpr()->getType());
+    }
+    // FALLTHROUGH
+  }
+
   // If we don't have a special case, fall back to the AST's constant evaluator.
   default: {
     // Don't try to come up with a value for materialized temporaries.