Re: [PATCH] Do not declare artificial variables in tree-profile.c to have a definition (PR lto/69188).

[Jeff Law <law@redhat.com>]

On 01/23/2017 03:05 AM, Kyrill Tkachov wrote:
>
> On 23/01/17 09:58, Christophe Lyon wrote:
>> On 13 January 2017 at 18:21, Jeff Law <law@redhat.com> wrote:
>>> On 01/13/2017 08:08 AM, Martin Liška wrote:
>>>> Hello.
>>>>
>>>> Nice example provided in the PR causes ICE as we have an artificial
>>>> symbol
>>>> created in tree-profile.c once being removed by remove unreachable
>>>> nodes
>>>> (-O0)
>>>> and once not (-O1). Well, difference is in process_references where
>>>> following hunk
>>>> prevent removal:
>>>>
>>>>                || (((before_inlining_p
>>>>                      && ((TREE_CODE (node->decl) != FUNCTION_DECL
>>>>                           && optimize)
>>>>
>>>> Anyway, these artificial symbols really should be just declarations as
>>>> they are defined
>>>> in libgcov library.
>>>>
>>>> Patch can bootstrap on ppc64le-redhat-linux and survives regression
>>>> tests.
>>>>
>>>> Ready to be installed?
>>>> Martin
>>>>
>>>>
>>>> 0001-Do-not-declare-artificial-variables-in-tree-profile..patch
>>>>
>>>>
>>>>  From 87262b1b60009381fd943fb433bc38f5d5685ac9 Mon Sep 17 00:00:00 2001
>>>> From: marxin <mliska@suse.cz>
>>>> Date: Fri, 13 Jan 2017 13:12:57 +0100
>>>> Subject: [PATCH] Do not declare artificial variables in
>>>> tree-profile.c to
>>>> have
>>>>   a definition (PR lto/69188).
>>>>
>>>> gcc/testsuite/ChangeLog:
>>>>
>>>> 2017-01-13  Martin Liska  <mliska@suse.cz>
>>>>
>>>>          PR lto/69188
>>>>          * gcc.dg/lto/pr69188_0.c: New test.
>>>>          * gcc.dg/lto/pr69188_1.c: New test.
>>>>
>>>> gcc/ChangeLog:
>>>>
>>>> 2017-01-13  Martin Liska  <mliska@suse.cz>
>>>>
>>>>          PR lto/69188
>>>>          * tree-profile.c (init_ic_make_global_vars): Do not call
>>>>          finalize_decl.
>>>>          (gimple_init_gcov_profiler): Likewise.
>>> OK.
>>> jeff
>>>
>> Hi,
>>
>> The new test fails on arm-none-eabi:
>> /cc6RcpEu.ltrans0.ltrans.o: In function `fn1':
>> <artificial>:(.text+0x18): undefined reference to
>> `__gcov_indirect_call_profiler_v2'
>> <artificial>:(.text+0x1c): undefined reference to
>> `__gcov_indirect_call_callee'
>> <artificial>:(.text+0x20): undefined reference to
>> `__gcov_indirect_call_callee'
>> <artificial>:(.text+0x60): undefined reference to
>> `__gcov_time_profiler_counter'
>> <artificial>:(.text+0x64): undefined reference to
>> `__gcov_time_profiler_counter'
>> <artificial>:(.text+0x80): undefined reference to
>> `__gcov_time_profiler_counter'
>> <artificial>:(.text+0x84): undefined reference to
>> `__gcov_time_profiler_counter'
>> /cc6RcpEu.ltrans0.ltrans.o: In function `_GLOBAL__sub_D_00100_1_fn1':
>> <artificial>:(.text+0xb8): undefined reference to `__gcov_exit'
>> /cc6RcpEu.ltrans0.ltrans.o: In function `main':
>> <artificial>:(.text+0xd4): undefined reference to
>> `__gcov_indirect_call_profiler_v2'
>> <artificial>:(.text+0xd8): undefined reference to
>> `__gcov_indirect_call_callee'
>> <artificial>:(.text+0xdc): undefined reference to
>> `__gcov_indirect_call_callee'
>> <artificial>:(.text+0x10c): undefined reference to
>> `__gcov_time_profiler_counter'
>> <artificial>:(.text+0x110): undefined reference to
>> `__gcov_time_profiler_counter'
>> /cc6RcpEu.ltrans0.ltrans.o: In function `_GLOBAL__sub_D_00100_1_main':
>> <artificial>:(.text+0x180): undefined reference to `__gcov_exit'
>> /cc6RcpEu.ltrans0.ltrans.o:(.data+0x4c): undefined reference to
>> `__gcov_merge_time_profile'
>> /cc6RcpEu.ltrans0.ltrans.o:(.data+0xac): undefined reference to
>> `__gcov_merge_time_profile'
>> collect2: error: ld returned 1 exit status
>>
>> FAIL: gcc.dg/lto/pr69188 c_lto_pr69188_0.o-c_lto_pr69188_1.o link,
>> -flto -O0 -fprofile-generate
>>
>> It works on arm-linux*.
>
> Hi,
>
> The testcase fails on bare-metal targets that don't support profiling.
> I believe it needs to be guarded with dg-require-profiling (I grepped
> around the testsuite for similar directives).
> With this patch the testcase appears unsupported on aarch64-none-elf
> where I observed the failure.
>
> Ok to commit?
>
> Thanks,
> Kyrill
>
> 2016-01-23  Kyrylo Tkachov  <kyrylo.tkachov@arm.com>
>
>     * gcc.dg/lto/pr69188_0.c: Require profiling support for testcase.
OK.
jeff