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C++ PATCH to fix ICEs with alignas and template parameter pack (PR c++/79653)
- From: Marek Polacek <polacek at redhat dot com>
- To: GCC Patches <gcc-patches at gcc dot gnu dot org>, Jason Merrill <jason at redhat dot com>
- Date: Wed, 22 Feb 2017 19:53:53 +0100
- Subject: C++ PATCH to fix ICEs with alignas and template parameter pack (PR c++/79653)
- Authentication-results: sourceware.org; auth=none
This patch oughta fix a couple of ice-on-invalids.
The parser.c part: I think it makes no sense for cp_parser_std_attribute_spec
to create an attribute if something went wrong, e.g. in make_pack_expansion, so
return error_mark_node to signal an issue.
The pt.c part: tsubst_pack_expansion can return error_mark_node to indicate
that it couldn't handle something, in which case we cannot use TREE_VEC_LENGTH
on the result.
Bootstrapped/regtested on x86_64-linux, ok for trunk?
2017-02-22 Marek Polacek <polacek@redhat.com>
PR c++/79653
* parser.c (cp_parser_std_attribute_spec): Don't build the attribute
if the alignas expression is erroneous.
* pt.c (tsubst_attribute): If tsubst_pack_expansion fails, return
error_mark_node.
* g++.dg/cpp0x/alignas10.C: New test.
* g++.dg/cpp0x/alignas9.C: New test.
diff --git gcc/cp/parser.c gcc/cp/parser.c
index 3992516..e20257c 100644
--- gcc/cp/parser.c
+++ gcc/cp/parser.c
@@ -24977,12 +24977,17 @@ cp_parser_std_attribute_spec (cp_parser *parser)
alignas_expr = cxx_alignas_expr (alignas_expr);
alignas_expr = build_tree_list (NULL_TREE, alignas_expr);
+ /* Handle alignas (pack...). */
if (cp_lexer_next_token_is (parser->lexer, CPP_ELLIPSIS))
{
cp_lexer_consume_token (parser->lexer);
alignas_expr = make_pack_expansion (alignas_expr);
}
+ /* Something went wrong, so don't build the attribute. */
+ if (alignas_expr == error_mark_node)
+ return error_mark_node;
+
if (cp_parser_require (parser, CPP_CLOSE_PAREN, RT_CLOSE_PAREN) == NULL)
{
cp_parser_error (parser, "expected %<)%>");
diff --git gcc/cp/pt.c gcc/cp/pt.c
index 38a01e1..5b0f62d 100644
--- gcc/cp/pt.c
+++ gcc/cp/pt.c
@@ -10012,6 +10012,8 @@ tsubst_attribute (tree t, tree *decl_p, tree args,
/* An attribute pack expansion. */
tree purp = TREE_PURPOSE (t);
tree pack = tsubst_pack_expansion (val, args, complain, in_decl);
+ if (pack == error_mark_node)
+ return error_mark_node;
int len = TREE_VEC_LENGTH (pack);
tree list = NULL_TREE;
tree *q = &list;
diff --git gcc/testsuite/g++.dg/cpp0x/alignas10.C gcc/testsuite/g++.dg/cpp0x/alignas10.C
index e69de29..164994e 100644
--- gcc/testsuite/g++.dg/cpp0x/alignas10.C
+++ gcc/testsuite/g++.dg/cpp0x/alignas10.C
@@ -0,0 +1,7 @@
+// PR c++/79653
+// { dg-do compile { target c++11 } }
+
+template <typename... A> struct outer {
+ template <typename... B> struct alignas(alignof(A) * alignof(B)...) inner {}; // { dg-error "mismatched argument pack lengths" }
+};
+outer<int>::inner<> mismatched_packs;
diff --git gcc/testsuite/g++.dg/cpp0x/alignas9.C gcc/testsuite/g++.dg/cpp0x/alignas9.C
index e69de29..98fe707 100644
--- gcc/testsuite/g++.dg/cpp0x/alignas9.C
+++ gcc/testsuite/g++.dg/cpp0x/alignas9.C
@@ -0,0 +1,6 @@
+// PR c++/79653
+// { dg-do compile { target c++11 } }
+
+template <typename... T>
+struct A { alignas(int...) char c; }; // { dg-error "no argument packs|expected" }
+A<int, double> a;
Marek