[MSVC Compat] Don't evaluate member base expressions w/o side effects
A member expression's base doesn't always have an impact on what the
member decl would evaluate to. In such a case, the base is used as a
poor man's scope qualifier.
This fixes PR26738.
Differential Revision: http://reviews.llvm.org/D17619
llvm-svn: 261975
diff --git a/clang/lib/AST/ExprConstant.cpp b/clang/lib/AST/ExprConstant.cpp
index 4089a20..89a21ac 100644
--- a/clang/lib/AST/ExprConstant.cpp
+++ b/clang/lib/AST/ExprConstant.cpp
@@ -4427,6 +4427,15 @@
void VisitIgnoredValue(const Expr *E) {
EvaluateIgnoredValue(Info, E);
}
+
+ /// Potentially visit a MemberExpr's base expression.
+ void VisitIgnoredBaseExpression(const Expr *E) {
+ // While MSVC doesn't evaluate the base expression, it does diagnose the
+ // presence of side-effecting behavior.
+ if (Info.getLangOpts().MSVCCompat && !E->HasSideEffects(Info.Ctx))
+ return;
+ VisitIgnoredValue(E);
+ }
};
}
@@ -4750,14 +4759,14 @@
bool LValueExprEvaluator::VisitMemberExpr(const MemberExpr *E) {
// Handle static data members.
if (const VarDecl *VD = dyn_cast<VarDecl>(E->getMemberDecl())) {
- VisitIgnoredValue(E->getBase());
+ VisitIgnoredBaseExpression(E->getBase());
return VisitVarDecl(E, VD);
}
// Handle static member functions.
if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(E->getMemberDecl())) {
if (MD->isStatic()) {
- VisitIgnoredValue(E->getBase());
+ VisitIgnoredBaseExpression(E->getBase());
return Success(MD);
}
}
@@ -6078,7 +6087,7 @@
}
bool VisitMemberExpr(const MemberExpr *E) {
if (CheckReferencedDecl(E, E->getMemberDecl())) {
- VisitIgnoredValue(E->getBase());
+ VisitIgnoredBaseExpression(E->getBase());
return true;
}