Constant expression evaluation refactoring:

 - Remodel Expr::EvaluateAsInt to behave like the other EvaluateAs* functions,
   and add Expr::EvaluateKnownConstInt to capture the current fold-or-assert
   behaviour.
 - Factor out evaluation of bitfield bit widths.
 - Fix a few places which would evaluate an expression twice: once to determine
   whether it is a constant expression, then again to get the value.

llvm-svn: 141561

2 files changed, 7 insertions, 5 deletions

diff --git a/clang/lib/StaticAnalyzer/Checkers/MallocOverflowSecurityChecker.cpp b/clang/lib/StaticAnalyzer/Checkers/MallocOverflowSecurityChecker.cpp
index 0f6b621bf7c..cf5501a4ac1 100644
--- a/clang/lib/StaticAnalyzer/Checkers/MallocOverflowSecurityChecker.cpp
+++ b/clang/lib/StaticAnalyzer/Checkers/MallocOverflowSecurityChecker.cpp
@@ -118,9 +118,12 @@ private:
     ASTContext &Context;
 
     bool isIntZeroExpr(const Expr *E) const {
-      return (E->getType()->isIntegralOrEnumerationType()
-              && E->isEvaluatable(Context)
-              && E->EvaluateAsInt(Context) == 0);
+      if (!E->getType()->isIntegralOrEnumerationType())
+        return false;
+      llvm::APSInt Result;
+      if (E->EvaluateAsInt(Result, Context))
+        return Result == 0;
+      return false;
     }
 
     void CheckExpr(const Expr *E_p) {
@@ -263,4 +266,3 @@ void MallocOverflowSecurityChecker::checkASTCodeBody(const Decl *D,
 void ento::registerMallocOverflowSecurityChecker(CheckerManager &mgr) {
   mgr.registerChecker<MallocOverflowSecurityChecker>();
 }
-
diff --git a/clang/lib/StaticAnalyzer/Core/BugReporter.cpp b/clang/lib/StaticAnalyzer/Core/BugReporter.cpp
index 9e1c12ce1f7..cdc9dcf7528 100644
--- a/clang/lib/StaticAnalyzer/Core/BugReporter.cpp
+++ b/clang/lib/StaticAnalyzer/Core/BugReporter.cpp
@@ -599,7 +599,7 @@ static void GenerateMinimalPathDiagnostic(PathDiagnostic& PD,
                 }
 
                 if (GetRawInt)
-                  os << LHS->EvaluateAsInt(PDB.getASTContext());
+                  os << LHS->EvaluateKnownConstInt(PDB.getASTContext());
 
                 os << ":'  at line "
                 << End.asLocation().getExpansionLineNumber();