Re: [PATCH] Skip gdb.base/break.exp catchpoint tests without catchpoints [PR34535]

[Tom Tromey <tom@tromey.com>]

>>>>> "Rainer" == Rainer Orth <ro@CeBiTec.Uni-Bielefeld.DE> writes:

Rainer> As detailed in PR PR testsuite/34535, the gdb.base/break.exp test FAILs
Rainer> on Solaris:

Thanks for the patch.

Rainer> While this patch avoids the failure, I wonder if there's some document
Rainer> on what it takes to actually implement catchpoints.

There's not really docs on anything.  However, most catchpoints are
implemented in break-catch-*.c.  Looking at break-catch-fork.c:

int
fork_catchpoint::insert_location (struct bp_location *bl)
{
  if (is_vfork)
    return target_insert_vfork_catchpoint (inferior_ptid.pid ());
  else
    return target_insert_fork_catchpoint (inferior_ptid.pid ());
}

So basically the target has to implement the insert_fork_catchpoint
target method; then arrange to tell gdb about TARGET_WAITKIND_FORKED
when appropriate.

Unfortunately the target methods don't have comments; while we try to
add descriptions nowadays, in the past gdb was lax about this :(
But there's a "paragraph" of them in target.h that you'd probably need
to handle:

    virtual int insert_fork_catchpoint (int)
      TARGET_DEFAULT_RETURN (1);
    virtual int remove_fork_catchpoint (int)
      TARGET_DEFAULT_RETURN (1);
    virtual int insert_vfork_catchpoint (int)
      TARGET_DEFAULT_RETURN (1);
    virtual int remove_vfork_catchpoint (int)
      TARGET_DEFAULT_RETURN (1);
    virtual void follow_fork (inferior *, ptid_t, target_waitkind, bool, bool)
      TARGET_DEFAULT_FUNC (default_follow_fork);

Rainer> +    set test "probe fork catchpoint"
Rainer> +    gdb_test_multiple "" $test {
Rainer> +	-re "Your system does not support this type.*" {
Rainer> +	    unsupported $test
Rainer> +	}
Rainer> +	-re "$::gdb_prompt $" {
Rainer> +	    set ::fork_catchpoints_supported 1
Rainer> +	    pass $test
Rainer> +	}
Rainer> +    }
Rainer> +}
 
Rainer> +    if {!$::fork_catchpoints_supported} {
Rainer> +	return
Rainer> +    }
Rainer> +
Rainer>      gdb_test "catch fork" "Catchpoint ${::decimal} \\(fork\\)" \
Rainer>  	"set catch fork, never expected to trigger"
 
I think it would be better to just use gdb_test_multiple here, and if
the "not supported" case is found, just return here.  That would avoid
starting another gdb.

thanks,
Tom