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Re: [PATCH] Limit alignment on error_mark_node variable
- From: "H.J. Lu" <hjl dot tools at gmail dot com>
- To: Richard Biener <richard dot guenther at gmail dot com>
- Cc: GCC Patches <gcc-patches at gcc dot gnu dot org>
- Date: Thu, 9 Jul 2015 04:08:47 -0700
- Subject: Re: [PATCH] Limit alignment on error_mark_node variable
- Authentication-results: sourceware.org; auth=none
- References: <20150708153211 dot GA14935 at intel dot com> <CAFiYyc0YLAMVNOOHWZh9m4XBPHwJ=ejx4wpvVrfNRc7u8Vh+RA at mail dot gmail dot com> <20150709095228 dot GA3414 at gmail dot com> <CAFiYyc1eUoM5Du4kxZ1HYB3QqkZXxz2M5LOvxYsX3XpbnJKRtA at mail dot gmail dot com>
On Thu, Jul 9, 2015 at 2:54 AM, Richard Biener
<richard.guenther@gmail.com> wrote:
> On Thu, Jul 9, 2015 at 11:52 AM, H.J. Lu <hjl.tools@gmail.com> wrote:
>> On Thu, Jul 09, 2015 at 10:16:38AM +0200, Richard Biener wrote:
>>> On Wed, Jul 8, 2015 at 5:32 PM, H.J. Lu <hongjiu.lu@intel.com> wrote:
>>> > There is no need to try different alignment on variable of
>>> > error_mark_node.
>>> >
>>> > OK for trunk if there is no regression?
>>>
>>> Can't we avoid calling align_variable on error_mark_node type decls
>>> completely? That is, punt earlier when we try to emit it.
>>>
>>
>> How about this? OK for trunk?
>
> Heh, you now get the obvious question why we can't simply avoid
> adding the varpool node in the first place ;)
>
When it was first added to varpool, its type was OK:
(gdb) bt
#0 varpool_node::get_create (decl=<var_decl 0x7ffff1506900 vv>)
at /export/gnu/import/git/sources/gcc/gcc/varpool.c:150
#1 0x0000000000e1c3e8 in rest_of_decl_compilation (
decl=<var_decl 0x7ffff1506900 vv>, top_level=1, at_end=0)
at /export/gnu/import/git/sources/gcc/gcc/passes.c:271
#2 0x0000000000731d39 in finish_decl (decl=<var_decl 0x7ffff1506900 vv>,
init_loc=0, init=<tree 0x0>, origtype=<tree 0x0>, asmspec_tree=<tree 0x0>)
at /export/gnu/import/git/sources/gcc/gcc/c/c-decl.c:4863
#3 0x000000000078d1ed in c_parser_declaration_or_fndef (
parser=0x7ffff15050a8, fndef_ok=false, static_assert_ok=true,
empty_ok=true, nested=false, start_attr_ok=true,
objc_foreach_object_declaration=0x0, omp_declare_simd_clauses=...)
at /export/gnu/import/git/sources/gcc/gcc/c/c-parser.c:1855
#4 0x000000000078c234 in c_parser_external_declaration (parser=0x7ffff15050a8)
at /export/gnu/import/git/sources/gcc/gcc/c/c-parser.c:1435
#5 0x000000000078be45 in c_parser_translation_unit (parser=0x7ffff15050a8)
at /export/gnu/import/git/sources/gcc/gcc/c/c-parser.c:1322
#6 0x00000000007b3271 in c_parse_file ()
at /export/gnu/import/git/sources/gcc/gcc/c/c-parser.c:15440
#7 0x000000000081cb97 in c_common_parse_file ()
at /export/gnu/import/git/sources/gcc/gcc/c-family/c-opts.c:1059
#8 0x0000000000f27662 in compile_file ()
at /export/gnu/import/git/sources/gcc/gcc/toplev.c:543
---Type <return> to continue, or q <return> to quit---
#9 0x0000000000f29baa in do_compile ()
at /export/gnu/import/git/sources/gcc/gcc/toplev.c:2041
#10 0x0000000000f29df9 in toplev::main (this=0x7fffffffdc90, argc=17,
argv=0x7fffffffdd98)
at /export/gnu/import/git/sources/gcc/gcc/toplev.c:2142
#11 0x00000000017d8228 in main (argc=17, argv=0x7fffffffdd98)
at /export/gnu/import/git/sources/gcc/gcc/main.c:39
Later, it was turned into error_mark_node:
Old value = <array_type 0x7ffff15ee150>
New value = <error_mark 0x7ffff14fac90>
finish_decl (decl=<var_decl 0x7ffff1506990 a>, init_loc=0, init=<tree 0x0>,
origtype=<tree 0x0>, asmspec_tree=<tree 0x0>)
at /export/gnu/import/git/sources/gcc/gcc/c/c-decl.c:4802
4802 if (TREE_USED (type))
(gdb) bt
#0 finish_decl (decl=<var_decl 0x7ffff1506990 a>, init_loc=0,
init=<tree 0x0>, origtype=<tree 0x0>, asmspec_tree=<tree 0x0>)
at /export/gnu/import/git/sources/gcc/gcc/c/c-decl.c:4802
#1 0x000000000078d1ed in c_parser_declaration_or_fndef (
parser=0x7ffff15050a8, fndef_ok=false, static_assert_ok=true,
empty_ok=true, nested=true, start_attr_ok=true,
objc_foreach_object_declaration=0x0, omp_declare_simd_clauses=...)
at /export/gnu/import/git/sources/gcc/gcc/c/c-parser.c:1855
#2 0x0000000000792a23 in c_parser_compound_statement_nostart (
parser=0x7ffff15050a8)
at /export/gnu/import/git/sources/gcc/gcc/c/c-parser.c:4621
#3 0x0000000000792688 in c_parser_compound_statement (parser=0x7ffff15050a8)
at /export/gnu/import/git/sources/gcc/gcc/c/c-parser.c:4532
#4 0x000000000078d5a3 in c_parser_declaration_or_fndef (
parser=0x7ffff15050a8, fndef_ok=true, static_assert_ok=true,
empty_ok=true, nested=false, start_attr_ok=true,
objc_foreach_object_declaration=0x0, omp_declare_simd_clauses=...)
at /export/gnu/import/git/sources/gcc/gcc/c/c-parser.c:1965
#5 0x000000000078c234 in c_parser_external_declaration (parser=0x7ffff15050a8)
at /export/gnu/import/git/sources/gcc/gcc/c/c-parser.c:1435
#6 0x000000000078be45 in c_parser_translation_unit (parser=0x7ffff15050a8)
at /export/gnu/import/git/sources/gcc/gcc/c/c-parser.c:1322
#7 0x00000000007b3271 in c_parse_file ()
---Type <return> to continue, or q <return> to quit---
at /export/gnu/import/git/sources/gcc/gcc/c/c-parser.c:15440
#8 0x000000000081cb97 in c_common_parse_file ()
at /export/gnu/import/git/sources/gcc/gcc/c-family/c-opts.c:1059
#9 0x0000000000f27662 in compile_file ()
at /export/gnu/import/git/sources/gcc/gcc/toplev.c:543
#10 0x0000000000f29baa in do_compile ()
at /export/gnu/import/git/sources/gcc/gcc/toplev.c:2041
#11 0x0000000000f29df9 in toplev::main (this=0x7fffffffdc90, argc=17,
argv=0x7fffffffdd98)
at /export/gnu/import/git/sources/gcc/gcc/toplev.c:2142
#12 0x00000000017d8228 in main (argc=17, argv=0x7fffffffdd98)
at /export/gnu/import/git/sources/gcc/gcc/main.c:39
(gdb)
I guess it isn't worth to take it out of varpool.
Is my patch OK for trunk?
--
H.J.