[Diagnostics] Check for integer overflow in array size expressions

Summary: Fixes PR27439

Reviewers: rsmith, Rakete1111

Reviewed By: rsmith

Subscribers: Rakete1111, cfe-commits

Differential Revision: https://reviews.llvm.org/D52750

llvm-svn: 344759

1 files changed, 13 insertions, 0 deletions

diff --git a/clang/lib/AST/ExprConstant.cpp b/clang/lib/AST/ExprConstant.cpp
index de0de5d13cd..c4d1245071d 100644
--- a/clang/lib/AST/ExprConstant.cpp
+++ b/clang/lib/AST/ExprConstant.cpp
@@ -10851,6 +10851,19 @@ APSInt Expr::EvaluateKnownConstInt(const ASTContext &Ctx,
   return EvalResult.Val.getInt();
 }
 
+APSInt Expr::EvaluateKnownConstIntCheckOverflow(
+    const ASTContext &Ctx, SmallVectorImpl<PartialDiagnosticAt> *Diag) const {
+  EvalResult EvalResult;
+  EvalResult.Diag = Diag;
+  EvalInfo Info(Ctx, EvalResult, EvalInfo::EM_EvaluateForOverflow);
+  bool Result = ::EvaluateAsRValue(Info, this, EvalResult.Val);
+  (void)Result;
+  assert(Result && "Could not evaluate expression");
+  assert(EvalResult.Val.isInt() && "Expression did not evaluate to integer");
+
+  return EvalResult.Val.getInt();
+}
+
 void Expr::EvaluateForOverflow(const ASTContext &Ctx) const {
   bool IsConst;
   EvalResult EvalResult;