On Thu, 9 Nov 2023 16:07:53 GMT, Mikael Vidstedt <[email protected]> wrote:
> This PR is splitting out the GCC 13.2.0 warning related changes from #16550, > excluding the Oracle/devkit parts, for clarity and to make potential > backports more straightforward. > > GCC 13.2.0 generates two new warnings: > > * linux-aarch64-debug > > src/hotspot/os_cpu/linux_aarch64/atomic_linux_aarch64.hpp:203:66: error: > 'long unsigned int __atomic_load_8(const volatile void*, int)' writing 8 > bytes into a region of size 0 overflows the destination > [-Werror=stringop-overflow=] > > I did not find any way to adjust the code to avoid this warning, so I instead > chose to disable it in `CompileJvm.gmk` for linux-aarch64-(fast)debug only. > > * linux-zero > > src/hotspot/share/runtime/thread.hpp:579:77: error: storing the address of > local variable 'rm' in '*_thr_current.Thread::_current_resource_mark' > [-Werror=dangling-pointer=] > > Lots and lots of warnings related to ResourceMark. Thanks to @stefank for > suggesting moving the ASSERT implementation of the ResourceMark constructor > to the .cpp file. With that change there's no need to explicitly disable the > warning. As for `dangling-pointer`, to be honest, I didn't fully understand why such a change could work. But it's nice to see that we can avoid compiler warnings by proper code modifications. As for `stringop-overflow`, we encountered this warning before. 1) https://bugs.openjdk.org/browse/JDK-8294031, gcc-12 raised the same warnings for the same file, i.e. `atomic_linux_aarch64.hpp`. After several fixes by @kimbarrett, this warning is gone. 2) https://bugs.openjdk.org/browse/JDK-8299580, gcc-12 also raised the same warnings for risc-v in the similar way, for file `atomic_linux_riscv.hpp`. And as suggested by @kimbarrett, this might be one fundamental problem and we can hold on before we fully understand it. Hi @kimbarrett, can we have your comments for this warning? Thanks. make/hotspot/lib/CompileJvm.gmk line 93: > 91: ifeq ($(DEBUG_LEVEL), fastdebug) > 92: ifeq ($(call And, $(call isTargetOs, linux) $(call isTargetCpu, > aarch64)), true) > 93: DISABLED_WARNINGS_gcc += stringop-overflow Do you think it would be better if we add some comments here? Suggestion: # False positive warnings for atomic_linux_aarch64.hpp on GCC >= 13 DISABLED_WARNINGS_gcc += stringop-overflow ------------- PR Review: https://git.openjdk.org/jdk/pull/16584#pullrequestreview-1723782910 PR Review Comment: https://git.openjdk.org/jdk/pull/16584#discussion_r1388766021
