gdb: remove unnecessary 'dir' commands from gdb-gdb.gdb script

While debugging GDB I used 'show directories' and spotted lots of
entries that didn't make much sense. Here are all the entries that are
in my directories list:

  /tmp/binutils-gdb/build
  /tmp/binutils-gdb/build/../../src/gdb
  /tmp/binutils-gdb/build/../../src/gdb/../bfd
  /tmp/binutils-gdb/build/../../src/gdb/../libiberty
  $cdir
  $cwd

Notice the second, third, and fourth entries in this list, these
should really be:

  /tmp/binutils-gdb/build/../src/gdb
  /tmp/binutils-gdb/build/../src/gdb/../bfd
  /tmp/binutils-gdb/build/../src/gdb/../libiberty

The problem is because I generally run everything from the top level
build directory, not the gdb/ sub-directory, thus, I start GDB like:

  ./gdb/gdb --data-directory ./gdb/data-directory

If run GDB under GDB, then I end up loading the gdb/gdb-gdb.gdb
script, which contains these lines:

  dir ../../src/gdb/../libiberty
  dir ../../src/gdb/../bfd
  dir ../../src/gdb
  dir .

These commands only make sense when running within the gdb/
sub-directory.

However, my debugging experience doesn't seem to be degraded at all, I
can still see the GDB source code just fine; which is because the
directory list still contains $cdir.

The build/gdb/gdb-gdb.gdb script is created from the
src/gdb/gdb-gdb.gdb.in template, which includes the automake @srcdir@
markers.

The 'dir' commands have mostly been around since the sourceware
repository was first created, though this commit 67f0714670383a did
reorder some of the 'dir' commands, which would seem to indicate these
commands were important to some people, at some time.

One possible fix would be to replace @srcdir@ with @abs_srcdir@, this
would ensure that the entries added were all valid, no matter the
user's current directory when debugging GDB.

However... I'd like to propose that we instead remove all the extra
directories completely.  My hope is that, with more recent tools, the
debug information should allow us to correctly find all of the source
files without having to add any extra 'dir' entries.  Obviously,
commit 67f0714670383a does make me a little nervous, but the
gdb-gdb.gdb script isn't something a non-maintainer will be using, so
I think we can afford to be a little more aggressive here.  If it
turns out the 'dir' entries are needed then we can add them back, but
actually document why they are needed.  Plus, when we add them back we
will use @abs_srcdir@ instead of @srcdir@.

Reviewed-By: Tom Tromey <tom@tromey.com>

diff --git a/gdb/gdb-gdb.gdb.in b/gdb/gdb-gdb.gdb.in
index 8d97c95a70e9830c98f853a1d42c166bd2d13b8b..b9fd457d069d044fdfe3136a7a1367c577979bd2 100644 (file)
--- a/gdb/gdb-gdb.gdb.in
+++ b/gdb/gdb-gdb.gdb.in
@@ -16,11 +16,6 @@ if !$gdb_init_done
     return
   end
 
-  dir @srcdir@/../libiberty
-  dir @srcdir@/../bfd
-  dir @srcdir@
-  dir .
-
   # Commands below are not fully compatible with wrapping into an 'if' block.
 end