Re: [PATCH] tests/docker: only enable ubsan for test-clang

[John Snow]

On 10/1/19 10:14 AM, Paolo Bonzini wrote:
> -fsanitize=undefined is not the same thing as --enable-sanitizers.  After
> commit 47c823e ("tests/docker: add sanitizers back to clang build", 
> 2019-09-11)
> test-clang is almost duplicating the asan (test-debug) test, so
> partly revert commit 47c823e5b while leaving ubsan enabled.
> 
> Signed-off-by: Paolo Bonzini <address@hidden>

I got confused by this:

```
  if compile_prog "$CPU_CFLAGS -Werror -fsanitize=undefined" ""; then
      have_ubsan=yes
  fi

```

it looked quite like --enable-sanitizers was indeed the same as
-fsanitize=undefined; or at least was a superset of such.

I suppose the argument you're making here is that we *only* want ubsan
for test-clang?

(I guess so, since test-debug also stipulates that clang be used; but
enables debug.)

In this case, is there a use for test-clang at all, actually?

--js


> ---
>  tests/docker/test-clang | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/tests/docker/test-clang b/tests/docker/test-clang
> index db9e697..8c51ead 100755
> --- a/tests/docker/test-clang
> +++ b/tests/docker/test-clang
> @@ -17,7 +17,9 @@ requires clang
>  
>  cd "$BUILD_DIR"
>  
> -OPTS="--cxx=clang++ --cc=clang --host-cc=clang --enable-sanitizers"
> +OPTS="--cxx=clang++ --cc=clang --host-cc=clang"
> +OPTS="$OPTS --extra-cflags=-fsanitize=undefined \
> +    --extra-cflags=-fno-sanitize=float-divide-by-zero"
>  build_qemu $OPTS
>  check_qemu
>  install_qemu
> 

-- 
—js