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Message-ID: <684ec15f-6407-430d-af8f-8751e9aa4c43@kernel.org>
Date: Thu, 8 Feb 2024 11:30:31 +0100
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Subject: Re: [PATCH 1/6] tools/rtla: Fix Makefile compiler options for clang
To: Nathan Chancellor <nathan@kernel.org>
Cc: Steven Rostedt <rostedt@goodmis.org>,
 Masami Hiramatsu <mhiramat@kernel.org>,
 Nick Desaulniers <ndesaulniers@google.com>, Bill Wendling
 <morbo@google.com>, Justin Stitt <justinstitt@google.com>,
 Donald Zickus <dzickus@redhat.com>, stable@vger.kernel.org,
 linux-trace-kernel@vger.kernel.org, linux-kernel@vger.kernel.org,
 llvm@lists.linux.dev
References: <cover.1707217097.git.bristot@kernel.org>
 <567ac1b94effc228ce9a0225b9df7232a9b35b55.1707217097.git.bristot@kernel.org>
 <20240206154835.GA1433705@dev-arch.thelio-3990X>
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From: Daniel Bristot de Oliveira <bristot@kernel.org>
In-Reply-To: <20240206154835.GA1433705@dev-arch.thelio-3990X>
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On 2/6/24 16:48, Nathan Chancellor wrote:
> On Tue, Feb 06, 2024 at 12:05:29PM +0100, Daniel Bristot de Oliveira wrote:
>> The following errors are showing up when compiling rtla with clang:
>>
>>  $ make HOSTCC=clang CC=clang LLVM_IAS=1
>>  [...]
>>
>>   clang -O -g -DVERSION=\"6.8.0-rc1\" -flto=auto -ffat-lto-objects
>> 	-fexceptions -fstack-protector-strong
>> 	-fasynchronous-unwind-tables -fstack-clash-protection  -Wall
>> 	-Werror=format-security -Wp,-D_FORTIFY_SOURCE=2
>> 	-Wp,-D_GLIBCXX_ASSERTIONS -Wno-maybe-uninitialized
>> 	$(pkg-config --cflags libtracefs)    -c -o src/utils.o src/utils.c
>>
>>   clang: warning: optimization flag '-ffat-lto-objects' is not supported [-Wignored-optimization-argument]
> 
> For what it's worth, this flag is supported in clang 17.0.0 and newer:
> 
> https://github.com/llvm/llvm-project/commit/610fc5cbcc8b68879c562f6458608afe2473ab7f

Good! still, I am getting this error on fedora, with this clang version:

bristot@x1:~/src/git/linux/tools/tracing/rtla$ clang --version
clang version 17.0.6 (Fedora 17.0.6-1.fc39)
Target: x86_64-redhat-linux-gnu
Thread model: posix
InstalledDir: /usr/bin

:-(

> But if it is not critical, just dropping the flag like you have done
> here rather than conditionally supporting it is probably easier.

Yeah, I will drop it for now, and keep monitoring.

Thanks Natan!
-- Daniel