[cfe-dev] clang built from source in Mac OSX 10.14 with apple-clang/Xcode missing stdlib from include search path

Wed Sep 25 05:49:57 PDT 2019

I'm always confused when trying to get locally-built Clang to find
stdlib headers on my Mac.

Last time, after upgrading to Mojave, following the TL;DR advice from
this answer made it work for me: https://stackoverflow.com/a/52530212

It would certainly be nice if this could somehow work out of the box.

On Wed, Sep 25, 2019 at 7:17 AM Jens Jorgensen via cfe-dev
<cfe-dev at lists.llvm.org> wrote:
>
> I recently cloned llvm from git and did a build of clang on my Macbook
> (OSX 10.14.6). I have Xcode (11.0) installed and built using Xcode's
> included apple-clang. The build worked fine but when I went to compile
> my project I got an error where it was trying to #include a stdlib
> header file. I'm not really sure but I think this is because in MacOS
> Mojave by default the os has System Integrity Protection enabled which
> among other things prevents modification to at least some locations
> under /usr (root user unable to ln -s ... /usr/include/c++, tried that).
> So Xcode does not install or symlink the standard library headers into
> /usr/include. apple-clang as installed already includes the installed
> stdlib header directories in its search path. Looking at the current git
> source I don't see a way to build clang to set a directory to look in
> for the stdlib. I did try -DGCC_INSTALL_PREFIX=... and that did not do
> the trick, apparently because it does not end up keeping that path for
> searching include <...>.
>
> I made a local git branch and made some changes to allow me to build a
> clang++ that includes the installed location in the include search path
> but before I log a bug/submit a change for review I wanted to see what
> constraints around this would end up being acceptable. Should the cmake
> scripts automatically pick this up by default on OSX if building with
> the Xcode-supplied compiler? Should it be structured/would it be useful
> to introduce a top-level #define to set this default stdlib search path
> in clang/include/clang/Config/config.h.cmake?
>
> For reference, here's a comparison on a test.cpp file containing simple
> #include <string>:
>
> ~/src/clang-build-20190828/bin/clang++  -v -c /tmp/test.cpp
> clang version 10.0.0 (https://github.com/llvm/llvm-project.git
> 92ed86d239cdd6ed97dae3084f6537088da88677)
> Target: x86_64-apple-darwin18.7.0
> Thread model: posix
> InstalledDir: /Users/user/src/clang-build-20190828/bin
>  "/Users/user/src/clang-build-20190828/bin/clang-10" -cc1 -triple
> x86_64-apple-macosx10.14.0 -Wdeprecated-objc-isa-usage
> -Werror=deprecated-objc-isa-usage -emit-obj -mrelax-all -disable-free
> -disable-llvm-verifier -discard-value-names -main-file-name test.cpp
> -mrelocation-model pic -pic-level 2 -mthread-model posix
> -mframe-pointer=all -masm-verbose -munwind-tables -target-cpu penryn
> -dwarf-column-info -debugger-tuning=lldb -ggnu-pubnames
> -target-linker-version 450.3 -v -coverage-notes-file
> /Users/user/src/llvm-project/test.gcno -resource-dir
> /Users/user/src/clang-build-20190828/lib/clang/10.0.0 -stdlib=libc++
> -internal-isystem
> /Users/user/src/clang-build-20190828/bin/../include/c++/v1
> -internal-isystem /usr/include/c++/v1 -internal-isystem
> /usr/local/include -internal-isystem
> /Users/user/src/clang-build-20190828/lib/clang/10.0.0/include
> -internal-externc-isystem /usr/include -fdeprecated-macro
> -fdebug-compilation-dir /Users/user/src/llvm-project -ferror-limit 19
> -fmessage-length 80 -stack-protector 1 -fblocks
> -fencode-extended-block-signature -fregister-global-dtors-with-atexit
> -fobjc-runtime=macosx-10.14.0 -fcxx-exceptions -fexceptions
> -fmax-type-align=16 -fdiagnostics-show-option -fcolor-diagnostics -o
> test.o -x c++ /tmp/test.cpp
> clang -cc1 version 10.0.0 based upon LLVM 10.0.0svn default target
> x86_64-apple-darwin18.7.0
> ignoring nonexistent directory
> "/Users/user/src/clang-build-20190828/bin/../include/c++/v1"
> ignoring nonexistent directory "/usr/include/c++/v1"
> #include "..." search starts here:
> #include <...> search starts here:
>  /usr/local/include
>  /Users/user/src/clang-build-20190828/lib/clang/10.0.0/include
>  /usr/include
>  /System/Library/Frameworks (framework directory)
>  /Library/Frameworks (framework directory)
> End of search list.
> /tmp/test.cpp:1:10: fatal error: 'string' file not found
> #include <string>
>          ^~~~~~~~
> 1 error generated.
>
>  and with the Xcode clang:
>
> clang++  -v -c /tmp/test.cpp
> Apple clang version 11.0.0 (clang-1100.0.33.8)
> Target: x86_64-apple-darwin18.7.0
> Thread model: posix
> InstalledDir:
> /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin
>  "/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/clang"
> -cc1 -triple x86_64-apple-macosx10.14.0 -Wdeprecated-objc-isa-usage
> -Werror=deprecated-objc-isa-usage -emit-obj -mrelax-all -disable-free
> -disable-llvm-verifier -discard-value-names -main-file-name test.cpp
> -mrelocation-model pic -pic-level 2 -mthread-model posix
> -mdisable-fp-elim -fno-strict-return -masm-verbose -munwind-tables
> -target-cpu penryn -dwarf-column-info -debugger-tuning=lldb
> -ggnu-pubnames -target-linker-version 512.4 -v -coverage-notes-file
> /Users/jbj1/src/llvm-project/test.gcno -resource-dir
> /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/lib/clang/11.0.0
> -stdlib=libc++ -internal-isystem
> /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../include/c++/v1
> -Wno-framework-include-private-from-public
> -Wno-atimport-in-framework-header -Wno-extra-semi-stmt
> -Wno-quoted-include-in-framework-header -fdeprecated-macro
> -fdebug-compilation-dir /Users/jbj1/src/llvm-project -ferror-limit 19
> -fmessage-length 80 -stack-protector 1 -mdarwin-stkchk-strong-link
> -fblocks -fencode-extended-block-signature
> -fregister-global-dtors-with-atexit -fobjc-runtime=macosx-10.14.0
> -fcxx-exceptions -fexceptions -fmax-type-align=16
> -fdiagnostics-show-option -fcolor-diagnostics -o test.o -x c++ /tmp/test.cpp
> clang -cc1 version 11.0.0 (clang-1100.0.33.8) default target
> x86_64-apple-darwin18.7.0
> ignoring nonexistent directory "/usr/include/c++/v1"
> #include "..." search starts here:
> #include <...> search starts here:
>  /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../include/c++/v1
>  /usr/local/include
>  /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/lib/clang/11.0.0/include
>  /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/include
>  /usr/include
>  /System/Library/Frameworks (framework directory)
>  /Library/Frameworks (framework directory)
> End of search list.
>
>
> --
> Jens B. Jorgensen
> jbj1 at ultraemail.net
>
>
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