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<p class="MsoNormal">/clang: sends to the ‘driver’. -Xclang sends to the ‘compiler instance’ (the -cc1 compiler), which the driver calls. They are actually the same executable which makes it a touch more confusing.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal"><b>From:</b> Gaier, Bjoern <Bjoern.Gaier@horiba.com> <br>
<b>Sent:</b> Wednesday, January 20, 2021 7:11 AM<br>
<b>To:</b> Keane, Erich <erich.keane@intel.com>; paul.robinson@sony.com; clang developer list <cfe-dev@lists.llvm.org><br>
<b>Subject:</b> RE: Clang function-sections flag<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><span lang="EN-GB">Using /clang:-fno-function-sections and /clang:-ffunction-sections were both accepted by Clang-cl while /clang:-planschbecken was rejected.</span><span lang="DE"><o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB"> </span><span lang="DE"><o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">Seems like that worked O_O Thank you!<br>
I gonna check if this will make a difference now.</span><span lang="DE"><o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB"> </span><span lang="DE"><o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">In the meantime… why isn’t /clang: and -Xclang the same?!</span><span lang="DE"><o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB"> </span><span lang="DE"><o:p></o:p></span></p>
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<p class="MsoNormal"><b>From:</b> Keane, Erich <<a href="mailto:erich.keane@intel.com">erich.keane@intel.com</a>>
<br>
<b>Sent:</b> 20 January 2021 16:07<br>
<b>To:</b> Gaier, Bjoern <<a href="mailto:Bjoern.Gaier@horiba.com">Bjoern.Gaier@horiba.com</a>>;
<a href="mailto:paul.robinson@sony.com">paul.robinson@sony.com</a>; clang developer list <<a href="mailto:cfe-dev@lists.llvm.org">cfe-dev@lists.llvm.org</a>><br>
<b>Subject:</b> RE: Clang function-sections flag<span lang="DE"><o:p></o:p></span></p>
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<p class="MsoNormal"><span lang="DE"> <o:p></o:p></span></p>
<p class="MsoNormal">Looks like CloudABI is the only triple that uses it by default. Presumably you aren’t on that, but I could also be missing something.<span lang="DE"><o:p></o:p></span></p>
<p class="MsoNormal"> <span lang="DE"><o:p></o:p></span></p>
<p class="MsoNormal">For me, it looks like BOTH -ffunction-sections and -fno-function-sections are unknown arguments in clang-cl, however if you use the /clang: syntax, both work. Can you try that?<span lang="DE"><o:p></o:p></span></p>
<p class="MsoNormal"> <span lang="DE"><o:p></o:p></span></p>
<p class="MsoNormal">/clang:-fno-function-sections<span lang="DE"><o:p></o:p></span></p>
<p class="MsoNormal"> <span lang="DE"><o:p></o:p></span></p>
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<p class="MsoNormal"><b>From:</b> cfe-dev <<a href="mailto:cfe-dev-bounces@lists.llvm.org">cfe-dev-bounces@lists.llvm.org</a>>
<b>On Behalf Of </b>Gaier, Bjoern via cfe-dev<br>
<b>Sent:</b> Wednesday, January 20, 2021 7:00 AM<br>
<b>To:</b> <a href="mailto:paul.robinson@sony.com">paul.robinson@sony.com</a>; <a href="mailto:cfe-dev@lists.llvm.org">
cfe-dev@lists.llvm.org</a><br>
<b>Subject:</b> Re: [cfe-dev] Clang function-sections flag<span lang="DE"><o:p></o:p></span></p>
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<p class="MsoNormal"> <span lang="DE"><o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">Hey Paul,</span><span lang="DE"><o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB"> </span><span lang="DE"><o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">I tried that already and got:</span><span lang="DE"><o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">“error: unknown argument: '-fno-function-sections'”</span><span lang="DE"><o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB"> </span><span lang="DE"><o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">I use Clang-Cl under Windows, creating an ELF file for x86_64-pc-windows-elf – however the flag is not supported (not with -Xclang but also not without)</span><span lang="DE"><o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">However “-ffunction-sections” is accepted (with -Xclang)</span><span lang="DE"><o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB"> </span><span lang="DE"><o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">Kind greetings</span><span lang="DE"><o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">Björn</span><span lang="DE"><o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB"> </span><span lang="DE"><o:p></o:p></span></p>
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<p class="MsoNormal"><b>From:</b> <a href="mailto:paul.robinson@sony.com">paul.robinson@sony.com</a> <<a href="mailto:paul.robinson@sony.com">paul.robinson@sony.com</a>>
<br>
<b>Sent:</b> 20 January 2021 15:56<br>
<b>To:</b> Gaier, Bjoern <<a href="mailto:Bjoern.Gaier@horiba.com">Bjoern.Gaier@horiba.com</a>>;
<a href="mailto:cfe-dev@lists.llvm.org">cfe-dev@lists.llvm.org</a><br>
<b>Subject:</b> RE: Clang function-sections flag<span lang="DE"><o:p></o:p></span></p>
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<p class="MsoNormal"><span lang="DE"> <o:p></o:p></span></p>
<p class="MsoNormal">Try adding -fno-function-sections to make sure it’s turned off (sounds like it is on by default for your target).<span lang="DE"><o:p></o:p></span></p>
<p class="MsoNormal">--paulr<span lang="DE"><o:p></o:p></span></p>
<p class="MsoNormal"> <span lang="DE"><o:p></o:p></span></p>
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<p class="MsoNormal"><b>From:</b> cfe-dev <<a href="mailto:cfe-dev-bounces@lists.llvm.org">cfe-dev-bounces@lists.llvm.org</a>>
<b>On Behalf Of </b>Gaier, Bjoern via cfe-dev<br>
<b>Sent:</b> Wednesday, January 20, 2021 5:01 AM<br>
<b>To:</b> Clang Dev <<a href="mailto:cfe-dev@lists.llvm.org">cfe-dev@lists.llvm.org</a>><br>
<b>Subject:</b> [cfe-dev] Clang function-sections flag<span lang="DE"><o:p></o:p></span></p>
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<p class="MsoNormal"> <span lang="DE"><o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">Hey Clang-people,</span><span lang="DE"><o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB"> </span><span lang="DE"><o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">I have a nooby question about the -ffunction-sections flag of Clang.
</span><span lang="DE"><o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">As far as I used to understand, setting this flag means, that every function gets their own section. Makes sense so far.</span><span lang="DE"><o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB"> </span><span lang="DE"><o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">Recently I started to look into the ELF format a bit so that subject came up. I created a macro to quickly generate me some functions:</span><span lang="DE"><o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">#define wuff(a, b) \</span><span lang="DE"><o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">a##b</span><span lang="DE"><o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB"> </span><span lang="DE"><o:p></o:p></span></p>
<p class="MsoNormal"><span lang="DE">#define crap(num) \<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="DE">int wuff(schwimmflugel, num) () \<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">{ \</span><span lang="DE"><o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB"> return num; \</span><span lang="DE"><o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">}</span><span lang="DE"><o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB"> </span><span lang="DE"><o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">Creating the object file and looking into it, I found a section header for every of my functions no matter if I set the -ffunction-sections flag or not.</span><span lang="DE"><o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">Also setting my function to static didn't changed a thing.... well besides from having those functions striped from my object file xD</span><span lang="DE"><o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB"> </span><span lang="DE"><o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">So... what does that flag effect?</span><span lang="DE"><o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB"> </span><span lang="DE"><o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">Kind greetings</span><span lang="DE"><o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">Björn</span><span lang="DE"><o:p></o:p></span></p>
<p class="MsoNormal"><span lang="DE">Als GmbH eingetragen im Handelsregister Bad Homburg v.d.H. HRB 9816, USt.ID-Nr. DE 114 165 789 Geschäftsführer: Dr. Hiroshi Nakamura, Dr. Robert Plank, Markus Bode, Takashi Nagano, Junichi Tajika, Ergin Cansiz.
<o:p></o:p></span></p>
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<p class="MsoNormal"><span lang="DE">Als GmbH eingetragen im Handelsregister Bad Homburg v.d.H. HRB 9816, USt.ID-Nr. DE 114 165 789 Geschäftsführer: Dr. Hiroshi Nakamura, Dr. Robert Plank, Markus Bode, Takashi Nagano, Junichi Tajika, Ergin Cansiz.
<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="DE">Als GmbH eingetragen im Handelsregister Bad Homburg v.d.H. HRB 9816, USt.ID-Nr. DE 114 165 789 Geschäftsführer: Dr. Hiroshi Nakamura, Dr. Robert Plank, Markus Bode, Takashi Nagano, Junichi Tajika, Ergin Cansiz.
<o:p></o:p></span></p>
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