configurator: make c file name last in compiler args to workaround clang bug #11123
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index 986cee9..3ca7459 100644
--- a/_build/.sandbox/beae43a6828cc6a280ceffe7f90d7970/default/test/blackbox-tests/test-cases/configurator-c-libraries.t/run.t
+++ b/_build/.sandbox/beae43a6828cc6a280ceffe7f90d7970/default/test/blackbox-tests/test-cases/configurator-c-libraries.t/run.t.corrected
@@ -10,4 +10,4 @@ link successfully
$ dune exec -- ./discover.exe
$ cat out
- 1
+ 0this is wrong. locally if I run this I get |
Re-order the compiler arguments so that the c file is last. This works around a clang bug which will suppress errors for unsupported flags if linker arguments come after the c file name. This suppression is a problem because it indicates that some argument is supported when it is not which can result in build errors. `https://github.com/llvm/llvm-project/issues/116278` eg: on aarch64 darwin and clang > 16 `-mpopcnt` will generate an error ``` $ clang -mpopcnt hello.c clang: error: unsupported option '-mpopcnt' for target 'aarch64-apple-darwin' $ echo $? 1 ``` however, if appending `-lpthread`: ``` $ clang -mpopcnt hello.c -lpthread $ echo $? 0 ``` Which is a problem as code will assume `-mpopcnt` is supported and will then break later when compiling with the unsupported flag Signed-off-by: Reno Dakota <paparodeo@proton.me>
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logged into the runner and sure enough gcc requires the args to be in order -- must succeed locally due to interaction with the gcc compiler wrapper on nix. anyway, this change won't work then. |
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Re-order the compiler arguments so the c file name is last. This works around a clang bug which will suppress errors for unsupported flags if linker arguments come after the c file name. This suppression is a problem because it indicates that some argument is supported when it is not which can result in build errors.
llvm/llvm-project#116278
after this change the
basemodule will build again with clang > 16 on systems without popcnt.https://github.com/janestreet/base/blob/6ddf3438c79184fa443727058b623ccfe1d82ead/src/discover/discover.ml#L13-L20
eg: on aarch64 darwin and clang > 16
-mpopcntwill generate an errorhowever, if appending
-lpthread:Which is a problem as code will assume
-mpopcntis supported and will then break later when compiling with the unsupported flag