Add Builtins.def attribute for "can be a constant expression".

 - Enabled for builtins which are always constant expressions
   (__builtin_huge_val*, __builtin_inf*, __builtin_constant_p,
   __builtin_classify_type, __builtin___CFStringMakeConstantString).

Added Builtin::Context::isConstantExpr.
 - Currently overly simply interface which only works for builtins
   whose constantexprness does not depend on their arguments.

CallExpr::isBuiltinConstantExpr now takes an ASTContext argument.

llvm-svn: 56983

1 files changed, 3 insertions, 6 deletions

diff --git a/clang/lib/AST/Expr.cpp b/clang/lib/AST/Expr.cpp
index 6a4b6b0493d..14b7b51ebb0 100644
--- a/clang/lib/AST/Expr.cpp
+++ b/clang/lib/AST/Expr.cpp
@@ -139,7 +139,7 @@ void CallExpr::setNumArgs(unsigned NumArgs) {
   this->NumArgs = NumArgs;
 }
 
-bool CallExpr::isBuiltinConstantExpr() const {
+bool CallExpr::isBuiltinConstantExpr(ASTContext &Ctx) const {
   // All simple function calls (e.g. func()) are implicitly cast to pointer to
   // function. As a result, we try and obtain the DeclRefExpr from the 
   // ImplicitCastExpr.
@@ -159,10 +159,7 @@ bool CallExpr::isBuiltinConstantExpr() const {
   if (!builtinID)
     return false;
 
-  // We have a builtin that is a constant expression
-  return builtinID == Builtin::BI__builtin___CFStringMakeConstantString ||
-         builtinID == Builtin::BI__builtin_classify_type ||
-         builtinID == Builtin::BI__builtin_huge_valf;
+  return Ctx.BuiltinInfo.isConstantExpr(builtinID);
 }
 
 bool CallExpr::isBuiltinClassifyType(llvm::APSInt &Result) const {
@@ -585,7 +582,7 @@ bool Expr::isConstantExpr(ASTContext &Ctx, SourceLocation *Loc) const {
     return true;
   case CallExprClass: {
     const CallExpr *CE = cast<CallExpr>(this);
-    if (CE->isBuiltinConstantExpr())
+    if (CE->isBuiltinConstantExpr(Ctx))
       return true;
     if (Loc) *Loc = getLocStart();
     return false;