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<p class="MsoNormal">Forgot to mention the platform is Linux. I found where clang++ automatically detects the C++ include path for libc++:<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Driver/ToolChains/Linux.cpp: <o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">DetectLibcxxIncludePath<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Not sure if this ever gets invoked from clang-check driver.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">/Riyaz<o:p></o:p></p>
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<p class="MsoNormal"><b>From:</b> cfe-dev [mailto:cfe-dev-bounces@lists.llvm.org]
<b>On Behalf Of </b>Riyaz Puthiyapurayil via cfe-dev<br>
<b>Sent:</b> Tuesday, April 24, 2018 8:24 PM<br>
<b>To:</b> cfe-dev@lists.llvm.org<br>
<b>Subject:</b> [cfe-dev] clang-check doesn't find C++ headers with -stdlib=libc++ option<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">I have clang, clang-check, libc++, libc++abi, etc. installed in a tree rooted in a non-standard location. The directory structure looks like this:<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><span style="font-family:Consolas">$CLANG_ROOT<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:Consolas">|_bin<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:Consolas">| |_ clang<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:Consolas">| |_ clang-check<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:Consolas">| |…<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:Consolas">|<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:Consolas">|_include<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:Consolas">| |_ various built-in C header files<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:Consolas">| |_c++<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:Consolas">| |_v1<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:Consolas">| |_ various libc++ header files<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:Consolas">|_lib -> lib64<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:Consolas">|_lib64<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:Consolas"> |_ various libraries<o:p></o:p></span></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Note that the above directory structure is standard, only the root directory is in a non-standard location. A simple C++ file like this:<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><span style="font-family:Consolas">// /tmp/fill.cpp<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:Consolas">#include <algorithm><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:Consolas">#include <vector><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:Consolas">std::vector<int> v{1, 2, 3};<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:Consolas">int main() {<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:Consolas"> std::fill(v.begin(), v.end(), -1);<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:Consolas"> return 0;<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:Consolas">}<o:p></o:p></span></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">compiles fine with clang++:<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><span style="font-family:Consolas">$ clang++ -std=c++11 -stdlib=libc++ /tmp/fill.cpp<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:Consolas">$<o:p></o:p></span></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">But with clang-check, it doesn’t compile fine even though compile_commands.json has the exact same clang “command”. Even specifying -stdlib=libc++ on the command line doesn’t work:<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><span style="font-family:Consolas">$ clang-check /tmp/fill.cpp -- -stdlib=libc++ -std=c++11 -xc++<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:Consolas">/tmp/fill.cpp:1:10: fatal error: 'algorithm' file not found<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:Consolas">#include <algorithm><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:Consolas"> ^~~~~~~~~~~<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:Consolas">1 error generated.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:Consolas">Error while processing /tmp/fill.cpp.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:Consolas">$<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:Consolas"><o:p> </o:p></span></p>
<p class="MsoNormal">But the following works:<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><span style="font-family:Consolas">$ clang-check /tmp/fill.cpp -- -std=c++11 -cxx-isystem ${CLANG_ROOT}/include/c++/v1<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:Consolas">$<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:Consolas"><o:p> </o:p></span></p>
<p class="MsoNormal">Why is clang-check not automatically inferring libc++ header paths the same way clang++ driver finds them? Is there some build configuration that can make clang tools find libc++ headers automatically when -stdlib=libc++ is specified.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">BTW, clang-check finds libstdc++ headers if –gcc-toolchain option is specified.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
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