Re: [PATCH 2/6] gdb/testsuite: fix gdb.trace/unavailable-dwarf-piece.exp with Clang

[Bruno Larsen <blarsen@redhat.com>]

On 11/11/2022 17:36, Andrew Burgess via Gdb-patches wrote:
> I noticed that the test gdb.trace/unavailable-dwarf-piece.exp was
> failing when run with Clang.  Or rather, the test was not running as
> the test executable failed to compile.
>
> The problem is that Clang was emitting this warning:
>
>    warning: argument unused during compilation: '-fdiagnostics-color=never' [-Wunused-command-line-argument]
>
> This warning is emitted when compiling the assembler file generated
> by the DWARF assembler.
>
> Most DWARF assembler tests generate the assembler file into a file
> with the '.S' extension.  However, this particular test uses a '.s'
> extension.
>
> Now a .S file will be passed through the preprocessor, while a .s will
> be sent straight to the assembler.  My guess is that Clang doesn't
> support the -fdiagnostics-color=never option for the assembler, but
> does for the preprocessor.
>
> That's a little annoying, but easily worked around.  We don't care if
> our assembler file is passed through the preprocessor, so, in this
> commit, I just change the file extension from .s to .S, and the
> problem is fixed.
>
> Currently, the unavailable-dwarf-piece.exp script names the assembler
> file using standard_output_file, in this commit I've switched to make
> use of standard_testfile, as that seems to be the more common way of
> doing this sort of thing.
>
> With these changes the test now passes with Clang 9.0.1 and 15.0.2,
> and also still passes with gcc.
> ---
>   gdb/testsuite/gdb.trace/unavailable-dwarf-piece.exp | 4 ++--
>   1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/gdb/testsuite/gdb.trace/unavailable-dwarf-piece.exp b/gdb/testsuite/gdb.trace/unavailable-dwarf-piece.exp
> index f80f8005fcf..13c6f38737c 100644
> --- a/gdb/testsuite/gdb.trace/unavailable-dwarf-piece.exp
> +++ b/gdb/testsuite/gdb.trace/unavailable-dwarf-piece.exp
> @@ -20,9 +20,9 @@ if {![dwarf2_support]} {
>       return 0
>   }
>   
> -standard_testfile .c
> +standard_testfile .c -dbg.S
>   
> -set asm_file [standard_output_file "${testfile}-dbg.s"]
> +set asm_file $srcfile2
>   set opts {}
>   
>   if  { [gdb_compile ${srcdir}/${subdir}/${srcfile} ${binfile}1.o \

I tried running this test with these changes using clang 14.0.5 and 
clang 16.0.0, and both times I got the following output:

builtin_spawn -ignore SIGHUP clang-14 -fdiagnostics-color=never 
-Wno-unknown-warning-option -w -c -g -o 
/home/blarsen/Documents/fsf_build/gdb/testsuite/temp/1163842/is_ilp32_target-1163842.o 
/home/blarsen/Documents/fsf_build/gdb/testsuite/temp/1163842/is_ilp32_target-1163842.c
/home/blarsen/Documents/fsf_build/gdb/testsuite/temp/1163842/is_ilp32_target-1163842.c:2:12: 
error: 'dummy' declared as an array with a negative size
         int dummy[sizeof (int) == 4
                   ^~~~~~~~~~~~~~~~~
1 error generated.


And I get an "unsupported" test. The error message says that the target 
doesn't support trace, but I'm not sure if it isn't related to the 
compilation failure. Do you see anything similar?

-- 
Cheers,
Bruno