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<p class="MsoNormal">I've been playing around with the scripts I use to build flang in and out of tree. I don't think I used to be able to do this, but I can now build the front end by only specifying "flang" in the define for "DLLVM_ENABLE_PROJECTS". Here's
my full build script for doing in in-tree build of the front end:<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">#!/bin/bash<o:p></o:p></p>
<p class="MsoNormal">cmake -G Ninja ../llvm \<o:p></o:p></p>
<p class="MsoNormal"> -DCMAKE_BUILD_TYPE=Release \<o:p></o:p></p>
<p class="MsoNormal"> -DFLANG_ENABLE_WERROR=On \<o:p></o:p></p>
<p class="MsoNormal"> -DLLVM_ENABLE_PROJECTS="flang" \<o:p></o:p></p>
<p class="MsoNormal"> -DCMAKE_CXX_STANDARD=17 \<o:p></o:p></p>
<p class="MsoNormal"> -DLLVM_TARGETS_TO_BUILD=host \<o:p></o:p></p>
<p class="MsoNormal"> -DLLVM_LIT_ARGS=-v \<o:p></o:p></p>
<p class="MsoNormal"> -DLLVM_INSTALL_UTILS=On \<o:p></o:p></p>
<p class="MsoNormal"> -DCMAKE_INSTALL_PREFIX=../install<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">When I build clang, flang, and mlir, it takes 6 minutes, 8 seconds and produces an install area of 1.9 GB. When I do in in-tree build of just the flang front end, it takes 4 minutes, 33 seconds and produces an install area of 1.3 GB.
When I do an out-of-tree build, it takes 1 minute 52 seconds, and produces a build area of 651 MB.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">All of these times are running on a powerful lab machine using the GNU C++ compiler.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Pete<o:p></o:p></p>
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