<html><head><meta http-equiv="Content-Type" content="text/html charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class="">Hi Jie,<div class=""><br class=""></div><div class="">I’m using a Mac with Xcode and found that specifying DLLVM_OPTIMIZED_TABLEGEN=On helped. Incremental builds are faster but tablegen files are run every time anyway, so it’s not actually a fix. I posted this issue before but it seems solving this is not that easy, at least for Xcode. </div><div class=""><br class=""></div><div class="">In the case of Xcode I found big speed improvements after saving the project xcuserdata folder in a safe place, deleting the entire “build” folder, re-creating a fresh “build” with cmake, and moving the xcuserdata folder I saved before in place. Unfortunately, this stops working as soon as I checkout branches, or pull commits from origin, so I need to repeat the same procedure to get fast compiles again.</div><div class=""><br class=""></div><div class="">John, </div><div class=""><br class=""></div><div class=""><br class=""><div><blockquote type="cite" class=""><div class="">On 21 Oct 2019, at 01:20, Jie Zhou via llvm-dev <<a href="mailto:llvm-dev@lists.llvm.org" class="">llvm-dev@lists.llvm.org</a>> wrote:</div><br class="Apple-interchange-newline"><div class="">
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Dear all,
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<div class="">I’m developing Clang&LLVM on MacOS Catalina 10.15.</div>
<div class="">Now every time I "<font face="Arial" class="">make clang"</font>, the building systems rebuilds</div>
<div class="">all the .inc files generated by cmake, which essentially</div>
<div class="">rebuilds all the tablegen files in llvm, although I did not</div>
<div class="">change any of the tablegen files. The building is unnecessary</div>
<div class="">and slow, especially when it builds the X86GenSubtargetInfo.inc.</div>
<div class="">Is there a way to prevent cmake generating Makefiles that</div>
<div class="">rebuilds all the tablegen files?</div>
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<div class="">Here is my command line to run cmake for generating Makefiles:</div>
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<div class="">cmake -G “Unix Makefiles” -DLLVM_TARGETS_TO_BUILD=“X86" -DCMAKE_BUILD_TYPE=Debug $(LLVM_SRC)</div>
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<div class="">The cmake version is 3.13.4. And I did not experience the same behavior on a Linux.</div>
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<div class="">Thanks,</div>
<div class="">- Jie</div>
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