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[PATCH][LTO] Fixup FIELD_DECLs in COMPONENT_REFs
- From: Richard Guenther <rguenther at suse dot de>
- To: gcc-patches at gcc dot gnu dot org
- Cc: Diego Novillo <dnovillo at google dot com>
- Date: Wed, 14 Oct 2009 17:55:27 +0200 (CEST)
- Subject: [PATCH][LTO] Fixup FIELD_DECLs in COMPONENT_REFs
The following replaces FIELD_DECLs with one from the canonical
type in COMPONENT_REFs. FIELD_DECLs are the most prominent thing
that we can't get rid of after type-merging because they are
still referenced from the IL (curiously it's also one example
for why we can't collect garbage after type-merging before streaming
in all IL we ever want to stream in).
This allows me to finish lto1 for 483.xalancbmk on a machine with
3GB ram where it previously failed running out of memory.
Wasting memory with yet-another hashtable for doing the replacement
would increase peak memory usage even further so I decided to do
stupid list walks. IL streaming after this patch is only taking
about 5% of the time we spend in fixing up decls and types before.
Bootstrapped and tested on x86_64-unknown-linux-gnu, a full SPEC 2006
is running. Ok if that passes?
Thanks,
Richard.
2009-10-14 Richard Guenther <rguenther@suse.de>
* tree.c (free_lang_data_in_decl): Free DECL_FCONTEXT.
* lto-streamer-in.c (input_gimple_stmt): Fixup FIELD_DECL
operands in COMPONENT_REFs.
Index: gcc/tree.c
===================================================================
*** gcc/tree.c (revision 152768)
--- gcc/tree.c (working copy)
*************** free_lang_data_in_decl (tree decl)
*** 4402,4407 ****
--- 4402,4411 ----
&& DECL_FIELD_OFFSET (decl)
&& TREE_CODE (DECL_FIELD_OFFSET (decl)) != INTEGER_CST)
DECL_FIELD_OFFSET (decl) = NULL_TREE;
+
+ /* DECL_FCONTEXT is only used for debug info generation. */
+ if (TREE_CODE (decl) == FIELD_DECL)
+ DECL_FCONTEXT (decl) = NULL_TREE;
}
else if (TREE_CODE (decl) == FUNCTION_DECL)
{
Index: gcc/lto-streamer-in.c
===================================================================
*** gcc/lto-streamer-in.c (revision 152768)
--- gcc/lto-streamer-in.c (working copy)
*************** input_gimple_stmt (struct lto_input_bloc
*** 948,953 ****
--- 948,979 ----
{
tree op = lto_input_tree (ib, data_in);
gimple_set_op (stmt, i, op);
+
+ /* Fixup FIELD_DECLs. */
+ while (op && handled_component_p (op))
+ {
+ if (TREE_CODE (op) == COMPONENT_REF)
+ {
+ tree field, type, tem;
+ field = TREE_OPERAND (op, 1);
+ type = DECL_CONTEXT (field);
+ for (tem = TYPE_FIELDS (type); tem; tem = TREE_CHAIN (tem))
+ {
+ if (tem == field
+ || ((DECL_FIELD_OFFSET (tem)
+ == DECL_FIELD_OFFSET (field))
+ && (DECL_FIELD_BIT_OFFSET (tem)
+ == DECL_FIELD_BIT_OFFSET (field))
+ && (DECL_OFFSET_ALIGN (tem)
+ == DECL_OFFSET_ALIGN (field))))
+ break;
+ }
+ gcc_assert (tem != NULL_TREE);
+ TREE_OPERAND (op, 1) = tem;
+ }
+
+ op = TREE_OPERAND (op, 0);
+ }
}
break;