[Bug c++/50255] Linker stumbles over non-grouped text/rodata for a non-virtual thunk
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50255 --- Comment #11 from Jakub Jelinek 2011-09-08 06:03:11 UTC --- Author: jakub Date: Thu Sep 8 06:03:01 2011 New Revision: 178675 URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=178675 Log: PR c++/50255 * method.c (use_thunk): If emitting thunk into the same section as function, use the same DECL_COMDAT_GROUP as well. Modified: branches/gcc-4_6-branch/gcc/cp/ChangeLog branches/gcc-4_6-branch/gcc/cp/method.c
[Bug c++/50255] Linker stumbles over non-grouped text/rodata for a non-virtual thunk
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50255 Jakub Jelinek changed: What|Removed |Added Status|NEW |ASSIGNED AssignedTo|unassigned at gcc dot |jakub at gcc dot gnu.org |gnu.org | --- Comment #10 from Jakub Jelinek 2011-09-07 15:27:16 UTC --- Created attachment 25223 --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=25223 gcc46-pr50255.patch Untested fix. If we decide to emit the thunk in the same section as the function, it'd better use the right comdat group as well.
[Bug c++/50255] Linker stumbles over non-grouped text/rodata for a non-virtual thunk
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50255 Jakub Jelinek changed: What|Removed |Added Status|UNCONFIRMED |NEW Last reconfirmed||2011-09-07 CC||jakub at gcc dot gnu.org Ever Confirmed|0 |1 --- Comment #9 from Jakub Jelinek 2011-09-07 14:33:52 UTC --- This changed on the trunk with Honza's Cgraph thunk reorg (which isn't really backportable): http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=173517 in r173516 we have .section .text._ZN1TI1WI1XEE1hEP1A,"axG",@progbits,_ZThn8_N1TI1WI1XEE1hEP1A,comdat .section .rodata._ZN1TI1WI1XEE1hEP1A,"aG",@progbits,_ZN1TI1WI1XEE1hEP1A,comdat .section .text._ZN1TI1WI1XEE1hEP1A,"axG",@progbits,_ZThn8_N1TI1WI1XEE1hEP1A,comdat while in r173517 .section .text._ZN1TI1WI1XEE1hEP1A,"axG",@progbits,_ZN1TI1WI1XEE1hEP1A,comdat .section .rodata._ZN1TI1WI1XEE1hEP1A,"aG",@progbits,_ZN1TI1WI1XEE1hEP1A,comdat .section .text._ZN1TI1WI1XEE1hEP1A,"axG",@progbits,_ZN1TI1WI1XEE1hEP1A,comdat
[Bug c++/50255] Linker stumbles over non-grouped text/rodata for a non-virtual thunk
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50255 --- Comment #8 from Stephan Bergmann 2011-09-07 12:14:56 UTC --- Created attachment 25221 --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=25221 script compiling test case and showing broken result I finally have a stripped down test case now that shows that compiling the given code leads to mismatched group names for the .text and .rodata sections of the non-virtual thunk (the first three .sections in the output).
[Bug c++/50255] Linker stumbles over non-grouped text/rodata for a non-virtual thunk
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50255 --- Comment #7 from Stephan Bergmann 2011-09-07 12:12:04 UTC --- Created attachment 25220 --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=25220 reduced test case
[Bug c++/50255] Linker stumbles over non-grouped text/rodata for a non-virtual thunk
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50255 --- Comment #6 from Stephan Bergmann 2011-09-02 13:15:42 UTC --- While I still don't have a stripped down test case, I at least know now what is going wrong (on recent gcc-4_6-branch rev 178396, at least): When compiling vbasheetobjects.cxx, the text section for the non-virtual thunk (with section name ".text._ZN19..." and group name "_ZThn20_N19...") is first obtained at get_section() hot_function_section() function_section_1() function_section_1() assemble_start_function() assemble_thunk() cgraph_expand_function() cgraph_expand_all_functions() cgraph_optimize() cgraph_finalize_compilation_unit() cp_write_global_declarations() compile_file() do_compile() toplev_main() main() There, get_section() is called with decl pointing to the thunk, as assemble_thunk() sets global current_function_decl = thunk_fndecl; Later on, the corresponding rodata section for the non-virtual thunk (with section name ".rodata._ZN19..." and erroneous group name "_ZN19..." instead of "_ZThn20_N19...") is first obtained at get_section() default_function_rodata_section() final_scan_insn() final() rest_of_handle_final() execute_one_pass() execute_pass_list() execute_pass_list() execute_pass_list() tree_rest_of_compilation() cgraph_expand_function() ... a few lines further down in the same invocation of cgraph_expand_function() (and in final_scan_insn() we are at switch_to_section(targetm.asm_out.function_rodata_section(current_function_decl));). But this time, current_function_decl points to the function itself, not the non-virtual thunk, as tree_rest_of_compilation() sets current_function_decl = fndecl;
[Bug c++/50255] Linker stumbles over non-grouped text/rodata for a non-virtual thunk
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50255 --- Comment #5 from Stephan Bergmann 2011-09-01 12:10:54 UTC --- By the way, the problem of the rodata section having a different GroupName than the text section is also present when you compile vbasheetobjects.cxx with plain (non-RedHat-modified) GCC 4.6.0 and GCC 4.6.1, respectively.
[Bug c++/50255] Linker stumbles over non-grouped text/rodata for a non-virtual thunk
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50255 --- Comment #4 from Stephan Bergmann 2011-09-01 08:39:59 UTC --- caolanm: will work on it, yes (wanted to clarify first whether looking at those group name mismatches is actually looking in the right direction)
[Bug c++/50255] Linker stumbles over non-grouped text/rodata for a non-virtual thunk
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50255 Caolan McNamara changed: What|Removed |Added CC||caolanm at redhat dot com, ||jakub at redhat dot com --- Comment #3 from Caolan McNamara 2011-09-01 08:29:54 UTC --- caolanm->jakub: this is the one I mentioned as FOSDEM 11. caolanm->sberg: able to attach something standalone that can reproduce this, i.e. .ii
[Bug c++/50255] Linker stumbles over non-grouped text/rodata for a non-virtual thunk
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50255 --- Comment #2 from Andrew Pinski 2011-08-31 21:06:43 UTC --- This sounds like http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49538 but without a testcase it is hard to say if it was really on the 4.6 branch or only with RedHat's compiler.
[Bug c++/50255] Linker stumbles over non-grouped text/rodata for a non-virtual thunk
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50255 --- Comment #1 from Andrew Pinski 2011-08-31 21:03:36 UTC --- >GCC 4.6.0 20110603 (Red Hat 4.6.0-10)). Does it happen with non RedHat version of the compiler meaning non modified version of GCC? Really you should have reported this first to redhat as they have some modifications to their compiler that might have caused this issue.
