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[Bug lto/46319] LTO plugin test failures with --with-build-config=bootstrap-lto --with-plugin-ld=ld
- From: "davek at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: Mon, 8 Nov 2010 04:53:05 +0000
- Subject: [Bug lto/46319] LTO plugin test failures with --with-build-config=bootstrap-lto --with-plugin-ld=ld
- Auto-submitted: auto-generated
- References: <bug-46319-4@http.gcc.gnu.org/bugzilla/>
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46319
--- Comment #8 from Dave Korn <davek at gcc dot gnu.org> 2010-11-08 04:52:12 UTC ---
The generated source file selfassign.so.ltrans0.s (and hence also the object
file selfassign.so.ltrans0.ltrans.o) file which gets created when lto-plugin
invokes lto1 on the original input selfassign.o file has no contents.
This appears to be because plugin_init in selfassign.c isn't marked with
__attribute__((externally_visible)), and the resolution file marks it as
PREVAILING_DEF_IRONLY. WPA then concludes that everything can be made static,
nothing is referenced, and discards the lot.
The consequence of this is that the object file that the pluging then adds back
into the link has no contents, so it doesn't override the symbol definitions
supplied from the IR when it first claimed the input selfassign.o file.
It works with GOLD because GOLD thinks the plugin's external symbols are
PREVAILING_DEF, not PREVAILING_DEF_IRONLY. This is the resolution file that
the lto-plugin writes based on what LD tells it at all_symbols_read time:
1
selfassign.o 27
5072 e2eb6ce9 PREVAILING_DEF_IRONLY plugin_init
5105 e2eb6ce9 UNDEF tree_check_failed
5114 e2eb6ce9 UNDEF tree_class_check_failed
5148 e2eb6ce9 UNDEF fancy_abort
5155 e2eb6ce9 UNDEF gimple_check_failed
5165 e2eb6ce9 UNDEF gimple_assign_single_p
5169 e2eb6ce9 UNDEF tree_contains_struct_check_failed
5253 e2eb6ce9 UNDEF build4_stat
5262 e2eb6ce9 UNDEF tree_operand_check_failed
5271 e2eb6ce9 UNDEF fold_build2_stat_loc
5279 e2eb6ce9 UNDEF build3_stat
5287 e2eb6ce9 UNDEF warning_at
5302 e2eb6ce9 UNDEF operand_equal_p
5308 e2eb6ce9 UNDEF maybe_get_identifier
5312 e2eb6ce9 UNDEF integer_zerop
5314 e2eb6ce9 UNDEF register_callback
5324 e2eb6ce9 UNDEF warning
5351 e2eb6ce9 UNDEF plugin_default_version_check
5494 e2eb6ce9 PREVAILING_DEF_IRONLY check_operator_eq
5536 e2eb6ce9 PREVAILING_DEF_IRONLY plugin_is_GPL_compatible
5433 e2eb6ce9 UNDEF tree_code_type
5442 e2eb6ce9 UNDEF tree_code_length
5452 e2eb6ce9 UNDEF gss_for_code_
5457 e2eb6ce9 UNDEF gimple_ops_offset_
5471 e2eb6ce9 UNDEF tree_contains_struct
5486 e2eb6ce9 UNDEF input_location
5502 e2eb6ce9 UNDEF cfun
... and here is the one generated when the plugin is loaded into GOLD:
1
selfassign.o 27
5072 e2eb6ce9 PREVAILING_DEF plugin_init
5105 e2eb6ce9 UNDEF tree_check_failed
5114 e2eb6ce9 UNDEF tree_class_check_failed
5148 e2eb6ce9 UNDEF fancy_abort
5155 e2eb6ce9 UNDEF gimple_check_failed
5165 e2eb6ce9 UNDEF gimple_assign_single_p
5169 e2eb6ce9 UNDEF tree_contains_struct_check_failed
5253 e2eb6ce9 UNDEF build4_stat
5262 e2eb6ce9 UNDEF tree_operand_check_failed
5271 e2eb6ce9 UNDEF fold_build2_stat_loc
5279 e2eb6ce9 UNDEF build3_stat
5287 e2eb6ce9 UNDEF warning_at
5302 e2eb6ce9 UNDEF operand_equal_p
5308 e2eb6ce9 UNDEF maybe_get_identifier
5312 e2eb6ce9 UNDEF integer_zerop
5314 e2eb6ce9 UNDEF register_callback
5324 e2eb6ce9 UNDEF warning
5351 e2eb6ce9 UNDEF plugin_default_version_check
5494 e2eb6ce9 PREVAILING_DEF check_operator_eq
5536 e2eb6ce9 PREVAILING_DEF plugin_is_GPL_compatible
5433 e2eb6ce9 UNDEF tree_code_type
5442 e2eb6ce9 UNDEF tree_code_length
5452 e2eb6ce9 UNDEF gss_for_code_
5457 e2eb6ce9 UNDEF gimple_ops_offset_
5471 e2eb6ce9 UNDEF tree_contains_struct
5486 e2eb6ce9 UNDEF input_location
5502 e2eb6ce9 UNDEF cfun