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C++ PATCH for bugs in strip_typedefs*

Message ID 555A1D24.7040504@redhat.com
State New
Headers show

Commit Message

Jason Merrill May 18, 2015, 5:11 p.m. UTC 
While looking at a bug report caused by failure to strip all typedefs, I 
came across a few latent bugs in the strip_typedefs functions.

First, if we're going to return a TREE_LIST unchanged we need to copy 
the pointer before we change the input variable.

Second, if we have a decltype with no typedefs in the argument, we still 
need to handle a typedef to that decltype.

Third, when we strip the operands of a TRAIT_EXPR we want to update the 
operands of the copy, not the original.

Tested x86_64-pc-linux-gnu, applying to trunk and 5.
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Patch

commit a5bfb34605c5ea629db6ff6db76cdaed0f675670
Author: Jason Merrill <jason@redhat.com>
Date:   Fri May 15 15:28:54 2015 -0400

    	* tree.c (strip_typedefs_expr) [TRAIT_EXPR]: Fix typo.
    	(strip_typedefs) [DECLTYPE_TYPE]: Fix typedef of decltype.
    	[TREE_LIST]: Fix no-change case.

diff --git a/gcc/cp/tree.c b/gcc/cp/tree.c
index ec9be8c..eebb415 100644
--- a/gcc/cp/tree.c
+++ b/gcc/cp/tree.c
@@ -1265,6 +1265,7 @@  strip_typedefs (tree t, bool *remove_attributes)
     {
       bool changed = false;
       vec<tree,va_gc> *vec = make_tree_vector ();
+      tree r = t;
       for (; t; t = TREE_CHAIN (t))
 	{
 	  gcc_assert (!TREE_PURPOSE (t));
@@ -1273,7 +1274,6 @@  strip_typedefs (tree t, bool *remove_attributes)
 	    changed = true;
 	  vec_safe_push (vec, elt);
 	}
-      tree r = t;
       if (changed)
 	r = build_tree_list_vec (vec);
       release_tree_vector (vec);
@@ -1411,7 +1411,7 @@  strip_typedefs (tree t, bool *remove_attributes)
       result = strip_typedefs_expr (DECLTYPE_TYPE_EXPR (t),
 				    remove_attributes);
       if (result == DECLTYPE_TYPE_EXPR (t))
-	return t;
+	result = NULL_TREE;
       else
 	result = (finish_decltype_type
 		  (result,
@@ -1496,8 +1496,8 @@  strip_typedefs_expr (tree t, bool *remove_attributes)
 	    && type2 == TRAIT_EXPR_TYPE2 (t))
 	  return t;
 	r = copy_node (t);
-	TRAIT_EXPR_TYPE1 (t) = type1;
-	TRAIT_EXPR_TYPE2 (t) = type2;
+	TRAIT_EXPR_TYPE1 (r) = type1;
+	TRAIT_EXPR_TYPE2 (r) = type2;
 	return r;
       }