Subject: bug#33709: Hang when compiled with --coverage and gcc 7.3

From: Eli Zaretskii <[email-masked]>
Date: Tue, 11 Dec 2018 21:27:39 +0200

> From: Glenn Morris <[email-masked]>
> Date: Tue, 11 Dec 2018 13:59:34 -0500
> 
> The Emacs hydra jobset at https://hydra.nixos.org/jobset/gnu/emacs-trunk
> was recently updated to a more recent version of the Nix package
> collection. Ever since then, the "coverage" job (which is the one that
> runs "make check") has timed out after spending hours failing to
> compiled the first test .el file.

Why do we use --coverage when running the test suite?

> bootstrap as normal
> ./make-dist --snapshot --no-check --no-changelog --no-compress
> tar xvf ../emacs-27.0.50.tar
> cd emacs-27.0.50
> 
> scl enable devtoolset-7  # this enables gcc 7.3.1 as the default compiler
> export CFLAGS=--coverage
> ./configure --without-all --without-x --without-libgmp
> make -j8
> 
> The build completes fine, but now eg:
> 
> ./src/emacs --help
> 
> never exits. It prints the usage message, then hangs.

"Hangs" as in "infloops"?  If so, where does it infloop?
Or does "hangs" mean something else here?

Thanks.