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<p class="MsoNormal">Hi all<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">I feel like we could make a few simple tweaks to the throwaway driver to make it a bit friendlier in situations like Justin’s.
<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
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<li class="MsoListParagraph" style="margin-left:0in;mso-list:l0 level1 lfo1">If flang, when invoked with no input source files, printed a message explaining that it was waiting on standard input then that would immediately have allowed Justin to understand
what was happening rather than have to contact the list.<o:p></o:p></li><li class="MsoListParagraph" style="margin-left:0in;mso-list:l0 level1 lfo1">Additionally, we could do a better job in the –help screen of explaining the default Flang behaviour when invoked without input files and with input files, including the F18_FC setting.
That would have helped him interpret the failure he was getting.<o:p></o:p></li><li class="MsoListParagraph" style="margin-left:0in;mso-list:l0 level1 lfo1">We could easily support -h as a synonym to –help, -help and -? which we already support, which would then have helped him find that info.<o:p></o:p></li></ul>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">I have posted some patches for review that do all three of these things:<o:p></o:p></p>
<p class="MsoNormal"><a href="https://reviews.llvm.org/D84855">https://reviews.llvm.org/D84855</a><o:p></o:p></p>
<p class="MsoNormal"><a href="https://reviews.llvm.org/D84856">https://reviews.llvm.org/D84856</a><o:p></o:p></p>
<p class="MsoNormal"><a href="https://reviews.llvm.org/D84857">https://reviews.llvm.org/D84857</a><o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">I feel like we should try and get this cherry picked to the LLVM 11 branch also.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Ta<o:p></o:p></p>
<p class="MsoNormal">Rich<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal"><b><span lang="EN-US">From:</span></b><span lang="EN-US"> flang-dev <flang-dev-bounces@lists.llvm.org>
<b>On Behalf Of </b>Steve Scalpone via flang-dev<br>
<b>Sent:</b> 24 June, 2020 22:51<br>
<b>To:</b> Szaday, Justin Josef <szaday2@illinois.edu>; flang-dev@lists.llvm.org <flang-dev@lists.llvm.org><br>
<b>Subject:</b> Re: [flang-dev] Difficulties with In-Tree Build of Flang<o:p></o:p></span></p>
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<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><span lang="EN-US" style="color:black">Hi Justin,<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="color:black"> <o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="color:black">The flang script reads from standard input if a source file is not provided on the command line. It appears to hang, but it’s really just waiting for input.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="color:black"> <o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="color:black">Flang isn’t hooked up to a code generator yet, so instead, by default, flang generates another Fortran source file and tries to compile that file with a different compiler. The default is pgf90, but
you can set the environment variable F18_FC to be a different compiler, like gfortran.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="color:black"> <o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="color:black">The flang script that you are running is just a throwaway driver until the real driver is ready. That work is under development right now, but I don’t know when it will be ready. Until then, we have
this quirky script that lets us test flang semantics.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="color:black"> <o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="color:black">- Steve<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
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<p class="MsoNormal" style="margin-left:.5in"><b><span lang="EN-US" style="font-size:12.0pt;color:black">From:
</span></b><span lang="EN-US" style="font-size:12.0pt;color:black">flang-dev <<a href="mailto:flang-dev-bounces@lists.llvm.org">flang-dev-bounces@lists.llvm.org</a>> on behalf of flang-dev <<a href="mailto:flang-dev@lists.llvm.org">flang-dev@lists.llvm.org</a>><br>
<b>Reply-To: </b>"Szaday, Justin Josef" <<a href="mailto:szaday2@illinois.edu">szaday2@illinois.edu</a>><br>
<b>Date: </b>Wednesday, June 24, 2020 at 2:02 PM<br>
<b>To: </b>flang-dev <<a href="mailto:flang-dev@lists.llvm.org">flang-dev@lists.llvm.org</a>><br>
<b>Subject: </b>[flang-dev] Difficulties with In-Tree Build of Flang<o:p></o:p></span></p>
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<p class="MsoNormal" style="margin-left:.5in"><span lang="EN-US"><o:p> </o:p></span></p>
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<p class="MsoNormal"><b><span style="font-size:7.5pt;font-family:"Verdana",sans-serif;color:black">External email: Use caution opening links or attachments</span></b><span style="font-size:7.5pt;font-family:"Verdana",sans-serif;color:black">
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<p class="MsoNormal" style="margin-left:.5in"><span lang="EN-US"><o:p> </o:p></span></p>
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<p class="MsoNormal" style="margin-left:.5in"><span lang="EN-US">Hello all,<o:p></o:p></span></p>
<p class="MsoNormal" style="margin-left:.5in"><span lang="EN-US"> <o:p></o:p></span></p>
<p class="MsoNormal" style="margin-left:.5in"><span lang="EN-US">I am having a very difficult time getting in-tree builds of Flang working. My build commands are as follows:<o:p></o:p></span></p>
<p class="MsoNormal" style="margin-left:.5in"><span lang="EN-US">cmake -G Ninja -DLLVM_ENABLE_PROJECTS="flang" -DCMAKE_INSTALL_PREFIX=$(pwd) -DCMAKE_BUILD_TYPE=MinSizeRel ../llvm<o:p></o:p></span></p>
<p class="MsoNormal" style="margin-left:.5in"><span lang="EN-US">cmake --build . --target check-flang<o:p></o:p></span></p>
<p class="MsoNormal" style="margin-left:.5in"><span lang="EN-US">cmake --build . --target install<o:p></o:p></span></p>
<p class="MsoNormal" style="margin-left:.5in"><span lang="EN-US"> <o:p></o:p></span></p>
<p class="MsoNormal" style="margin-left:.5in"><span lang="EN-US">The build itself completes successfully, and all the Flang tests pass when using “check-flang”; however, “flang -v” and “flang -h” hang (it does not produce any output and has to be killed) and,
when trying to compile a program, I get the error message “execvp(pgf90) failed: No such file or directory” (which fails even if I set F18_FC to gfortran or flang). I have tried building it on a few machines to no avail. I have tested both the Debug and MinSizeRel
build types, used both Ninja and Unix Makefiles to build it, and tested a few different versions of GCC/G++, ultimately settling on v9.1.0. I am building from master of the llvm-project GitHub repository.<o:p></o:p></span></p>
<p class="MsoNormal" style="margin-left:.5in"><span lang="EN-US"> <o:p></o:p></span></p>
<p class="MsoNormal" style="margin-left:.5in"><span lang="EN-US">Any insights here would be appreciated, I am at a loss about what else to try here. Any other debugging suggestions or usage tips would be appreciated as well.<o:p></o:p></span></p>
<p class="MsoNormal" style="margin-left:.5in"><span lang="EN-US"> <o:p></o:p></span></p>
<p class="MsoNormal" style="margin-left:.5in"><span lang="EN-US">Thanks,<o:p></o:p></span></p>
<p class="MsoNormal" style="margin-left:.5in"><span lang="EN-US">Justin<o:p></o:p></span></p>
<p class="MsoNormal" style="margin-left:.5in"><span lang="EN-US"> <o:p></o:p></span></p>
<p class="MsoNormal" style="margin-left:.5in"><span lang="EN-US"> <o:p></o:p></span></p>
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