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

1 files changed, 6 insertions, 0 deletions

diff --git a/clang/lib/AST/Decl.cpp b/clang/lib/AST/Decl.cpp
index 7d3390f1334..5cd98584bf9 100644
--- a/clang/lib/AST/Decl.cpp
+++ b/clang/lib/AST/Decl.cpp
@@ -2187,6 +2187,12 @@ bool FieldDecl::isAnonymousStructOrUnion() const {
   return false;
 }
 
+unsigned FieldDecl::getBitWidthValue(const ASTContext &Ctx) const {
+  assert(isBitField() && "not a bitfield");
+  Expr *BitWidth = InitializerOrBitWidth.getPointer();
+  return BitWidth->EvaluateKnownConstInt(Ctx).getZExtValue();
+}
+
 unsigned FieldDecl::getFieldIndex() const {
   if (CachedFieldIndex) return CachedFieldIndex - 1;