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[PATCH] Fix PR c++/31517: ICE on invalid initialization of static member of a template class
- From: Simon Martin <simartin at users dot sourceforge dot net>
- To: gcc-patches at gcc dot gnu dot org
- Date: Tue, 17 Apr 2007 00:29:07 +0200
- Subject: [PATCH] Fix PR c++/31517: ICE on invalid initialization of static member of a template class
Hi all.
The following invalid snippet currently gives an ICE:
=== cut here ===
template <typename> struct A
{
static const int i=0;
};
template <typename T> const int A<T>::i = 0=0;
=== cut here ===
We call 'value_dependent_expression_p' with the "second" definition of
A<T>::i (0=0), which is a MODOP_EXPR with a NOP_EXPR (with no operand) as
second operand (a MODOP_EXPR's second operand only carries a tree code). This
results in the call of 'value_dependent_expression_p' with each of the
MODOP_EXPR's operands.
When working on the second one, 'value_dependent_expression_p' calls itself
with the NOP_EXPR's operand, that is NULL_TREE, and we end up with a
segmentation fault.
(One can note that the same testcase but without the in-class definition does
not segfault because in that case, the decl for A<T>::i is not a
DECL_INTEGRAL_CONSTANT_VAR_P, so we skip the call to
'value_dependent_expression_p' in decl.c:5130)
The attached patch fixes this PR by teaching 'value_dependent_expression_p' to
handle MODOP_EXPR properly, that is only call itself with the 0-th and 2-nd
operands.
I've successfully regtested it on i686-pc-linux-gnu. Is it OK for mainline?
For the 4.2 and 4.1 branches?
Thanks in advance,
Simon
:ADDPATCH c++:
2007-04-17 Simon Martin <simartin@users.sourceforge.net>
PR c++/31517
* pt.c (value_dependent_expression_p): Handle MODOP_EXPRs.
Index: gcc/cp/pt.c
===================================================================
--- gcc/cp/pt.c (revision 123881)
+++ gcc/cp/pt.c (working copy)
@@ -14949,6 +14949,10 @@ value_dependent_expression_p (tree expre
|| (type2 ? dependent_type_p (type2) : false));
}
+ case MODOP_EXPR:
+ return ((value_dependent_expression_p (TREE_OPERAND (expression, 0)))
+ || (value_dependent_expression_p (TREE_OPERAND (expression, 2))));
+
default:
/* A constant expression is value-dependent if any subexpression is
value-dependent. */
2007-04-17 Simon Martin <simartin@users.sourceforge.net>
PR c++/31517
* g++.dg/template/init7.C: New test.
/* PR c++/31517. This used to ICE. */
/* { dg-do "compile" } */
template<typename> struct A
{
static const int i=0;
};
template<typename T> const int A<T>::i = 0=0; /* { dg-error "duplicate initialization" } */