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Use TYPE_NEXT_VARIANT instead of TREE_CHAIN as chain_next for types during GC (PR c++/46400)

Message ID 20110624144358.GX16443@tyan-ft48-01.lab.bos.redhat.com
State New
Headers show

Commit Message

Jakub Jelinek June 24, 2011, 2:43 p.m. UTC 
Hi!

On the huge testcase in the PR we ICE, because GC needs too deep recursion.
I've noticed that part of the problem is deep recursion through
TYPE_NEXT_VARIANT pointers.
As TREE_CHAIN on types is TYPE_STUB_DECL, therefore should point
to a different kind of tree and thus isn't really a pointer through
which long chain of trees are linked together, I think we should
use TYPE_NEXT_VARIANT as such chain instead.
In fact, the C FE already uses it, just for INTEGER_TYPEs only.
This patch changes both C and C++ FEs to use it for all types.

The patch fixes the testcase (while without the patch it needs
roughly 35MB of stack, with the patch 5.25MB is enough) and has been
bootstrapped/regtested on x86_64-linux and i686-linux.  Ok for trunk?

2011-06-24  Jakub Jelinek  <jakub@redhat.com>

	PR c++/46400
	* cp-tree.h (union lang_tree_node): Use TYPE_NEXT_VARIANT
	instead of TYPE_CHAIN for chain_next for types.

	* c-decl.c (union lang_tree_node): Use TYPE_NEXT_VARIANT
	instead of TYPE_CHAIN for chain_next for types.


	Jakub

Comments

Joseph Myers June 24, 2011, 6:29 p.m. UTC | #1 
On Fri, 24 Jun 2011, Jakub Jelinek wrote:

> 	* c-decl.c (union lang_tree_node): Use TYPE_NEXT_VARIANT
> 	instead of TYPE_CHAIN for chain_next for types.

The C changes are OK.
Jason Merrill June 24, 2011, 9:07 p.m. UTC | #2 
OK.

Jason
Richard Henderson June 24, 2011, 10:21 p.m. UTC | #3 
On 06/24/2011 07:43 AM, Jakub Jelinek wrote:
> +       chain_next ("CODE_CONTAINS_STRUCT (TREE_CODE (&%h.generic), TS_TYPE_COMMON) ? ((union lang_tree_node *) TYPE_NEXT_VARIANT (&%h.generic)) : CODE_CONTAINS_STRUCT (TREE_CODE (&%h.generic), TS_COMMON) ? ((union lang_tree_node *) TREE_CHAIN (&%h.generic)) : NULL"))) lang_tree_node {

Is it possible to break this out into an inline (or, i suppose, out of line)
function?  This is getting fairly unreadable...


r~
diff mbox

Patch

--- gcc/cp/cp-tree.h.jj	2011-06-21 16:45:52.000000000 +0200
+++ gcc/cp/cp-tree.h	2011-06-24 12:07:42.000000000 +0200
@@ -729,7 +729,7 @@  enum cp_tree_node_structure_enum {
 
 /* The resulting tree type.  */
 union GTY((desc ("cp_tree_node_structure (&%h)"),
-       chain_next ("CODE_CONTAINS_STRUCT (TREE_CODE (&%h.generic), TS_COMMON) ? ((union lang_tree_node *) TREE_CHAIN (&%h.generic)) : NULL"))) lang_tree_node {
+       chain_next ("CODE_CONTAINS_STRUCT (TREE_CODE (&%h.generic), TS_TYPE_COMMON) ? ((union lang_tree_node *) TYPE_NEXT_VARIANT (&%h.generic)) : CODE_CONTAINS_STRUCT (TREE_CODE (&%h.generic), TS_COMMON) ? ((union lang_tree_node *) TREE_CHAIN (&%h.generic)) : NULL"))) lang_tree_node {
   union tree_node GTY ((tag ("TS_CP_GENERIC"),
 			desc ("tree_node_structure (&%h)"))) generic;
   struct template_parm_index_s GTY ((tag ("TS_CP_TPI"))) tpi;
--- gcc/c-decl.c.jj	2011-06-17 11:02:19.000000000 +0200
+++ gcc/c-decl.c	2011-06-24 12:13:35.000000000 +0200
@@ -238,7 +238,7 @@  extern char C_SIZEOF_STRUCT_LANG_IDENTIF
 /* The resulting tree type.  */
 
 union GTY((desc ("TREE_CODE (&%h.generic) == IDENTIFIER_NODE"),
-       chain_next ("TREE_CODE (&%h.generic) == INTEGER_TYPE ? (union lang_tree_node *) TYPE_NEXT_VARIANT (&%h.generic) : CODE_CONTAINS_STRUCT (TREE_CODE (&%h.generic), TS_COMMON) ? ((union lang_tree_node *) TREE_CHAIN (&%h.generic)) : NULL")))  lang_tree_node
+       chain_next ("CODE_CONTAINS_STRUCT (TREE_CODE (&%h.generic), TS_TYPE_COMMON) ? (union lang_tree_node *) TYPE_NEXT_VARIANT (&%h.generic) : CODE_CONTAINS_STRUCT (TREE_CODE (&%h.generic), TS_COMMON) ? ((union lang_tree_node *) TREE_CHAIN (&%h.generic)) : NULL")))  lang_tree_node
  {
   union tree_node GTY ((tag ("0"),
 			desc ("tree_node_structure (&%h)")))