Re: [PATCH 5/5] lto: Support #pragma GCC diagnostic [PR80922] [PR106823] [PR107936]
Torbjorn SVENSSON <[email protected]> Wed, 5 Aug 2026 08:52:41 +0200
| Newsgroups | gmane.comp.gcc.patches |
|---|---|
| Message-ID | <[email protected]> |
On 2026-08-05 02:06, Lewis Hyatt wrote:
> On Tue, Aug 04, 2026 at 02:31:51PM +0200, Torbjorn SVENSSON wrote:
>> Hello,
>>
>> The new gcc.dg/lto/pr80922 test appears to fail for all arm-none-eabi targets:
>>
>> Testing gcc.dg/lto/pr80922-2, -O0 -flto -flto-partition=none -fuse-linker-plugin
>> doing compile
>> Executing on host: /build/r17-2833-g32657f29f91871/bin/arm-none-eabi-gcc -mthumb -march=armv6s-m -mcpu=cortex-m0 -mfloat-abi=soft -mfpu=auto -fdiagnostics-plain-output -O0 -flto -flto-partition=none -fuse-linker-plugin -O2 -Wfree-nonheap-object -c -o c_lto_pr80922-2_0.o /build/gcc_src/gcc/testsuite/gcc.dg/lto/pr80922-2_0.c (timeout = 800)
>> spawn -ignore SIGHUP /build/r17-2833-g32657f29f91871/bin/arm-none-eabi-gcc -mthumb -march=armv6s-m -mcpu=cortex-m0 -mfloat-abi=soft -mfpu=auto -fdiagnostics-plain-output -O0 -flto -flto-partition=none -fuse-linker-plugin -O2 -Wfree-nonheap-object -c -o c_lto_pr80922-2_0.o /build/gcc_src/gcc/testsuite/gcc.dg/lto/pr80922-2_0.c
>> pid is 703324 -703324
>> pid is -1
>> output is status 0
>> PASS: gcc.dg/lto/pr80922-2 c_lto_pr80922-2_0.o assemble, -O0 -flto -flto-partition=none -fuse-linker-plugin
>> doing compile
>> Executing on host: /build/r17-2833-g32657f29f91871/bin/arm-none-eabi-gcc -mthumb -march=armv6s-m -mcpu=cortex-m0 -mfloat-abi=soft -mfpu=auto -fdiagnostics-plain-output -O0 -flto -flto-partition=none -fuse-linker-plugin -O2 -Wfree-nonheap-object -c -o c_lto_pr80922-2_1.o /build/gcc_src/gcc/testsuite/gcc.dg/lto/pr80922-2_1.c (timeout = 800)
>> spawn -ignore SIGHUP /build/r17-2833-g32657f29f91871/bin/arm-none-eabi-gcc -mthumb -march=armv6s-m -mcpu=cortex-m0 -mfloat-abi=soft -mfpu=auto -fdiagnostics-plain-output -O0 -flto -flto-partition=none -fuse-linker-plugin -O2 -Wfree-nonheap-object -c -o c_lto_pr80922-2_1.o /build/gcc_src/gcc/testsuite/gcc.dg/lto/pr80922-2_1.c
>> pid is 703370 -703370
>> pid is -1
>> output is status 0
>> PASS: gcc.dg/lto/pr80922-2 c_lto_pr80922-2_1.o assemble, -O0 -flto -flto-partition=none -fuse-linker-plugin
>> doing compile
>> Executing on host: /build/r17-2833-g32657f29f91871/bin/arm-none-eabi-gcc -mthumb -march=armv6s-m -mcpu=cortex-m0 -mfloat-abi=soft -mfpu=auto -fdiagnostics-plain-output -O0 -flto -flto-partition=none -fuse-linker-plugin -O2 -Wfree-nonheap-object -c -o c_lto_pr80922-2_2.o /build/gcc_src/gcc/testsuite/gcc.dg/lto/pr80922-2_2.c (timeout = 800)
>> spawn -ignore SIGHUP /build/r17-2833-g32657f29f91871/bin/arm-none-eabi-gcc -mthumb -march=armv6s-m -mcpu=cortex-m0 -mfloat-abi=soft -mfpu=auto -fdiagnostics-plain-output -O0 -flto -flto-partition=none -fuse-linker-plugin -O2 -Wfree-nonheap-object -c -o c_lto_pr80922-2_2.o /build/gcc_src/gcc/testsuite/gcc.dg/lto/pr80922-2_2.c
>> pid is 703406 -703406
>> pid is -1
>> output is status 0
>> PASS: gcc.dg/lto/pr80922-2 c_lto_pr80922-2_2.o assemble, -O0 -flto -flto-partition=none -fuse-linker-plugin
>> doing compile
>> Executing on host: /build/r17-2833-g32657f29f91871/bin/arm-none-eabi-gcc c_lto_pr80922-2_1.o c_lto_pr80922-2_2.o -mthumb -march=armv6s-m -mcpu=cortex-m0 -mfloat-abi=soft -mfpu=auto -dumpbase "" -fdiagnostics-plain-output -r --specs=rdimon.specs -Wl,--start-group -lc -lm -Wl,--end-group --specs=nosys.specs -Wl,--allow-multiple-definition -Wl,-u,_isatty,-u,_fstat -Wl,-wrap,exit -Wl,-wrap,_exit -Wl,-wrap,main -Wl,-wrap,abort -Wl,gcc_tg.o -o c_lto_pr80922-2.o (timeout = 800)
>> spawn -ignore SIGHUP /build/r17-2833-g32657f29f91871/bin/arm-none-eabi-gcc c_lto_pr80922-2_1.o c_lto_pr80922-2_2.o -mthumb -march=armv6s-m -mcpu=cortex-m0 -mfloat-abi=soft -mfpu=auto -dumpbase -fdiagnostics-plain-output -r --specs=rdimon.specs -Wl,--start-group -lc -lm -Wl,--end-group --specs=nosys.specs -Wl,--allow-multiple-definition -Wl,-u,_isatty,-u,_fstat -Wl,-wrap,exit -Wl,-wrap,_exit -Wl,-wrap,main -Wl,-wrap,abort -Wl,gcc_tg.o -o c_lto_pr80922-2.o
>> pid is 703440 -703440
>> /build/r17-2833-g32657f29f91871/arm-none-eabi/bin/ld: warning: incremental linking of LTO and non-LTO objects; using -flinker-output=nolto-rel which will bypass whole program optimization
>> In function 'myfree2',
>> inlined from 'main' at /build/gcc_src/gcc/testsuite/gcc.dg/lto/pr80922-1_1.c:8:3:
>> /build/gcc_src/gcc/testsuite/gcc.dg/lto/pr80922-2_1.c:5:3: warning: '__builtin_free' called on unallocated object 'a' [-Wfree-nonheap-object]
>> /build/gcc_src/gcc/testsuite/gcc.dg/lto/pr80922-1_1.c: In function 'main':
>> /build/gcc_src/gcc/testsuite/gcc.dg/lto/pr80922-1_1.c:4:13: note: declared here
>> In function 'myfree2',
>> inlined from 'main' at /build/gcc_src/gcc/testsuite/gcc.dg/lto/pr80922-1_1.c:8:3:
>> /build/gcc_src/gcc/testsuite/gcc.dg/lto/pr80922-2_1.c:10:3: warning: '__builtin_free' called on unallocated object 'c' [-Wfree-nonheap-object]
>> /build/gcc_src/gcc/testsuite/gcc.dg/lto/pr80922-1_1.c: In function 'main':
>> /build/gcc_src/gcc/testsuite/gcc.dg/lto/pr80922-1_1.c:4:19: note: declared here
>> pid is -1
>> output is /build/r17-2833-g32657f29f91871/arm-none-eabi/bin/ld: warning: incremental linking of LTO and non-LTO objects; using -flinker-output=nolto-rel which will bypass whole program optimization
>> In function 'myfree2',
>> inlined from 'main' at /build/gcc_src/gcc/testsuite/gcc.dg/lto/pr80922-1_1.c:8:3:
>> /build/gcc_src/gcc/testsuite/gcc.dg/lto/pr80922-2_1.c:5:3: warning: '__builtin_free' called on unallocated object 'a' [-Wfree-nonheap-object]
>> /build/gcc_src/gcc/testsuite/gcc.dg/lto/pr80922-1_1.c: In function 'main':
>> /build/gcc_src/gcc/testsuite/gcc.dg/lto/pr80922-1_1.c:4:13: note: declared here
>> In function 'myfree2',
>> inlined from 'main' at /build/gcc_src/gcc/testsuite/gcc.dg/lto/pr80922-1_1.c:8:3:
>> /build/gcc_src/gcc/testsuite/gcc.dg/lto/pr80922-2_1.c:10:3: warning: '__builtin_free' called on unallocated object 'c' [-Wfree-nonheap-object]
>> /build/gcc_src/gcc/testsuite/gcc.dg/lto/pr80922-1_1.c: In function 'main':
>> /build/gcc_src/gcc/testsuite/gcc.dg/lto/pr80922-1_1.c:4:19: note: declared here
>> status 0
>> FAIL: gcc.dg/lto/pr80922-2 c_lto_pr80922-2_2.o-c_lto_pr80922-2_2.o link, incr-link
>> doing compile
>> Executing on host: /build/r17-2833-g32657f29f91871/bin/arm-none-eabi-gcc c_lto_pr80922-2_0.o c_lto_pr80922-2.o -mthumb -march=armv6s-m -mcpu=cortex-m0 -mfloat-abi=soft -mfpu=auto -dumpbase "" -fdiagnostics-plain-output -O0 -flto -flto-partition=none -fuse-linker-plugin -O2 -Wfree-nonheap-object --specs=rdimon.specs -Wl,--start-group -lc -lm -Wl,--end-group --specs=nosys.specs -Wl,--allow-multiple-definition -Wl,-u,_isatty,-u,_fstat -Wl,-wrap,exit -Wl,-wrap,_exit -Wl,-wrap,main -Wl,-wrap,abort -Wl,gcc_tg.o -T qemu.ld -o gcc-dg-lto-pr80922-2-01.exe (timeout = 800)
>> spawn -ignore SIGHUP /build/r17-2833-g32657f29f91871/bin/arm-none-eabi-gcc c_lto_pr80922-2_0.o c_lto_pr80922-2.o -mthumb -march=armv6s-m -mcpu=cortex-m0 -mfloat-abi=soft -mfpu=auto -dumpbase -fdiagnostics-plain-output -O0 -flto -flto-partition=none -fuse-linker-plugin -O2 -Wfree-nonheap-object --specs=rdimon.specs -Wl,--start-group -lc -lm -Wl,--end-group --specs=nosys.specs -Wl,--allow-multiple-definition -Wl,-u,_isatty,-u,_fstat -Wl,-wrap,exit -Wl,-wrap,_exit -Wl,-wrap,main -Wl,-wrap,abort -Wl,gcc_tg.o -T qemu.ld -o gcc-dg-lto-pr80922-2-01.exe
>> pid is 703533 -703533
>> pid is -1
>> output is status 0
>> FAIL: gcc.dg/lto/pr80922-2 (test for LTO warnings, pr80922-2_0.c line 10 -O0 -flto -flto-partition=none -fuse-linker-plugin)
>> FAIL: gcc.dg/lto/pr80922-2 (test for LTO warnings, pr80922-2_0.c line 15 -O0 -flto -flto-partition=none -fuse-linker-plugin)
>> FAIL: gcc.dg/lto/pr80922-2 (test for LTO warnings, pr80922-2_1.c line 5 -O0 -flto -flto-partition=none -fuse-linker-plugin)
>> FAIL: gcc.dg/lto/pr80922-2 (test for LTO warnings, pr80922-2_1.c line 10 -O0 -flto -flto-partition=none -fuse-linker-plugin)
>> PASS: gcc.dg/lto/pr80922-2 c_lto_pr80922-2_0.o-c_lto_pr80922-2.o link, -O0 -flto -flto-partition=none -fuse-linker-plugin
>>
>>
>> Kind regards,
>> Torbjörn
>
> Thanks, so the test is expecting an LTO-only partial link, and it gets
> tripped up because this target adds an extra non-LTO wrapper object to every
> link. The attached patch disables the test using
> check_effective_target_unwrapped, which I think is the way to go for now? It
> works fine on x86-64, fwiw, in that the incr-link test still runs as
> before. I don't think I have a way to test on arm-none-eabi myself, unless
> there is a cfarm machine I have not found for that...
I've tested below patch on top of r17-2833-g32657f29f91871 and it appears to do the job. I do, however, not know if there is any better solution than disabling the incr-link.
What impact do you think it would have to compile the testglue.c from dejagnu with -flto? Would that be a better solution?
If think it's possible to add -flto when building testglue.c by adding
set_board_info wrap_compile_flags "-flto"
to the board definition. Perhaps, this is something that the harness in GCC should do?
Kind regards,
Torbjörn
>
> -Lewis
>
>
> 0001-lto-testsuite-Skip-incr-link-tests-on-targets-with-wra.txt
>
> [PATCH] lto: testsuite: Skip incr-link tests on targets with wrapper object [PR80922]
>
> The new incr-link LTO test expects to perform an LTO incremental link, but
> targets making use of a wrapper object add a non-LTO object to the link, in
> which case the test needs to be skipped.
>
> gcc/testsuite/ChangeLog:
>
> PR middle-end/80922
> * lib/lto.exp: Skip incremental linking test for wrapped targets.
> ---
> gcc/testsuite/lib/lto.exp | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/gcc/testsuite/lib/lto.exp b/gcc/testsuite/lib/lto.exp
> index 7243547a52d..db19ff00855 100644
> --- a/gcc/testsuite/lib/lto.exp
> +++ b/gcc/testsuite/lib/lto.exp
> @@ -854,7 +854,9 @@ proc lto-execute-1 { src1 sid } {
> # Only attempt the incr-link mode if the linker plugin is explicitly in use.
> set sav_compile_type $compile_type
> set sav_obj_list $obj_list
> - if { $is_incr_link && [lsearch -exact $option "-fuse-linker-plugin"] < 0 } {
> + if { $is_incr_link
> + && ([lsearch -exact $option "-fuse-linker-plugin"] < 0
> + || ![check_effective_target_unwrapped]) } {
> set compile_type "link"
> } elseif { $is_incr_link || $is_ar_link } {
> set mainsrc [lindex $obj_list 0]