clang-tools: teach about nix's include path #73345

Mic92 · 2019-11-13T14:42:11Z

By translating NIX_CFLAGS_COMPILE to CPATH,
all tools will now find c headers properly,
when run in a nix-shell.

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Mic92 · 2019-11-13T14:43:39Z

pkgs/development/tools/clang-tools/default.nix

+
+    export clang=${clang}
+    substituteAll ${./wrapper} $out/bin/clangd
+    chmod +x $out/bin/clangd
    for tool in \
      clang-apply-replacements \
      clang-check \
      clang-format \


Should we skip this one from being wrapped?

Mic92 · 2019-11-13T14:52:40Z

Might be worth a backport

Mic92 · 2019-11-13T16:44:23Z

Tested with non-trivial C projects and clangd.
Also tested with C++.

matthewbauer · 2019-11-13T18:21:20Z

pkgs/development/tools/clang-tools/wrapper

+  local path
+  while (( $# )); do
+    case $1 in
+        -isystem|-I)


idirafter could also be used.

I just noticed parsing of -I was wrong anyway, since there can be no space in between. Since we only use -isystem right now in stdenv, I just simplified the code of the wrapper rather than having a half broken implementation for -I. -Idirafter is also not used in nixpkgs.

By translating NIX_CFLAGS_COMPILE to CPATH, all tools will now find c headers properly, when run in a nix-shell.

clang-tools: teach about nix's include path (cherry picked from commit f3759a6)

nixos-discourse · 2019-11-17T20:30:46Z

This pull request has been mentioned on NixOS Discourse. There might be relevant details there:

https://discourse.nixos.org/t/clang-tooling-woes-on-nixos/2314/15

tazjin · 2020-05-19T19:11:25Z

Do you think changing the order of CPATH and libcpp_includes in the CPLUS_INCLUDE_PATH is feasible and would work?

Did you ever get around to submitting a change like this? I'm running into what I suspect is the same error at the moment and am wondering how deep I should dig :)

Mic92 · 2020-05-19T22:57:14Z

There is an alternative to @knedlsepp proposal: With https://github.com/NixOS/nixpkgs/pull/85189/files#diff-ae6d7fc8f1059168bd391972ef177c31R40 one could include the platforms native c++ headers. Don't know what the latest state of this is, but @Ericson2314 might know more.

knedlsepp · 2020-05-20T04:54:15Z

I don't think I could ever get this working 100%. I only got a local project specific workaround that basically breaks the C-only backend but makes C++ work. :-\

Vonfry · 2020-08-18T01:22:20Z

Do you think changing the order of CPATH and libcpp_includes in the CPLUS_INCLUDE_PATH is feasible and would work?

I met the same problem recently. It is solved by changing the order of CPATH and libcpp_includes.

By the way, buildcpath seemed not to work for me, it also returns an empty string.

Would someone modify the wrap or make it working more genericly?

Mic92 · 2020-08-18T06:10:42Z

Do you think changing the order of CPATH and libcpp_includes in the CPLUS_INCLUDE_PATH is feasible and would work?

I met the same problem recently. It is solved by changing the order of CPATH and libcpp_includes.

By the way, buildcpath seemed not to work for me, it also returns an empty string.

Would someone modify the wrap or make it working more genericly?

If it returns an empty string, you might be not in a nix-shell. Make sure that NIX_CFLAGS_COMPILE is not empty.

Mic92 · 2020-08-18T06:11:33Z

@knedlsepp @tazjin This PR should fix your problems with math.h: https://github.com/NixOS/nixpkgs/pull/95733/files
At least in theory, I need to build/test it.

Vonfry · 2020-08-18T06:45:04Z

I retried it and find the reason. The wrap is always worked under bash, it is not a problem. The one is caused by glibc and libc++ is more important.

buildcpath can work in a bash shell by nix-shell -p bash, but it cannot work in zsh.

$1(${NIX_CFLAGS_COMPILE}) is splitted by space in bash, but not in zsh. So the case can match -isystem in bash not in zsh.

Mic92 · 2020-08-18T06:58:04Z

I retried it and find the reason. The wrap is always worked under bash, it is not a problem. The one is caused by glibc and libc++ is more important.

buildcpath can work in a bash shell by nix-shell -p bash, but it cannot work in zsh.

$1(${NIX_CFLAGS_COMPILE}) is splitted by space in bash, but not in zsh. So the case can match -isystem in bash not in zsh.

In our wrapper it should be always bash. So that should be not a problem.

Mic92 requested a review from dtzWill November 13, 2019 14:42

Mic92 commented Nov 13, 2019

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ofborg bot requested a review from aherrmann November 13, 2019 14:51

ofborg bot added 10.rebuild-darwin: 1-10 10.rebuild-linux: 1-10 labels Nov 13, 2019

Mic92 force-pushed the fix-clang-tools branch from ae06bf0 to 1240f96 Compare November 13, 2019 14:52

Mic92 force-pushed the fix-clang-tools branch 2 times, most recently from 1174555 to 5c23507 Compare November 13, 2019 14:59

matthewbauer reviewed Nov 13, 2019

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clang-tools: teach about nix's include path

a10ef1a

By translating NIX_CFLAGS_COMPILE to CPATH, all tools will now find c headers properly, when run in a nix-shell.

Mic92 force-pushed the fix-clang-tools branch from 5c23507 to a10ef1a Compare November 13, 2019 18:30

Mic92 merged commit f3759a6 into NixOS:master Nov 17, 2019

Mic92 deleted the fix-clang-tools branch November 17, 2019 10:37

Mic92 mentioned this pull request Nov 17, 2019

clang-tools: teach about nix's include path [19.09] #73546

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dtzWill pushed a commit to dtzWill/nixpkgs that referenced this pull request Nov 17, 2019

clang-tools: teach about nix's include path (NixOS#73345)

f3853e7

clang-tools: teach about nix's include path (cherry picked from commit f3759a6)

Mic92 mentioned this pull request Aug 18, 2020

stdenv: expose libc/c++ stdlib header at runtime #95733

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clang-tools: teach about nix's include path #73345

clang-tools: teach about nix's include path #73345

Mic92 commented Nov 13, 2019 •

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Mic92 Nov 13, 2019

Mic92 commented Nov 13, 2019

Mic92 commented Nov 13, 2019

matthewbauer Nov 13, 2019

Mic92 Nov 13, 2019 •

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nixos-discourse commented Nov 17, 2019

tazjin commented May 19, 2020

Mic92 commented May 19, 2020

knedlsepp commented May 20, 2020 •

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Vonfry commented Aug 18, 2020 •

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Mic92 commented Aug 18, 2020

Vonfry commented Aug 18, 2020 •

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Mic92 commented Aug 18, 2020

clang-tools: teach about nix's include path #73345

clang-tools: teach about nix's include path #73345

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Mic92 commented Nov 13, 2019 • edited

Motivation for this change

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Mic92 commented Nov 13, 2019

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tazjin commented May 19, 2020

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knedlsepp commented May 20, 2020 • edited

Vonfry commented Aug 18, 2020 • edited

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Mic92 commented Nov 13, 2019 •

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Mic92 Nov 13, 2019 •

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knedlsepp commented May 20, 2020 •

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