When determining whether an expression refers to a bit-field, look

into the left-hand side of an assignment expression. This completes
most of PR3500; the only remaining part is to deal with the
GCC-specific implementation-defined behavior for "unsigned long" (and
other) bit-fields.

llvm-svn: 70623

1 files changed, 10 insertions, 4 deletions

diff --git a/clang/lib/AST/Expr.cpp b/clang/lib/AST/Expr.cpp
index d89290bbb97..19d67bb7f8a 100644
--- a/clang/lib/AST/Expr.cpp
+++ b/clang/lib/AST/Expr.cpp
@@ -1379,13 +1379,19 @@ bool Expr::isNullPointerConstant(ASTContext &Ctx) const
   return isIntegerConstantExpr(Result, Ctx) && Result == 0;
 }
 
-/// isBitField - Return true if this expression is a bit-field.
-bool Expr::isBitField() {
+FieldDecl *Expr::getBitField() {
   Expr *E = this->IgnoreParenCasts();
+
   if (MemberExpr *MemRef = dyn_cast<MemberExpr>(E))
     if (FieldDecl *Field = dyn_cast<FieldDecl>(MemRef->getMemberDecl()))
-        return Field->isBitField();
-  return false;
+      if (Field->isBitField())
+        return Field;
+
+  if (BinaryOperator *BinOp = dyn_cast<BinaryOperator>(E))
+    if (BinOp->isAssignmentOp() && BinOp->getLHS())
+      return BinOp->getLHS()->getBitField();
+
+  return 0;
 }
 
 /// isArrow - Return true if the base expression is a pointer to vector,