diff mbox series

[2/2] gdbhooks: Add attempt to invoke on-gcc-hooks-load

Message ID ZqtSgzKxKeAkaCsf@arm.com
State Committed
Commit f01df5e47b2551e0f435a9efa8e0a30142f3d46b
Headers
Series [1/2] gdbhooks: Make dot viewer configurable |

Checks

Context Check Description
linaro-tcwg-bot/tcwg_gcc_build--master-aarch64 success Build passed
linaro-tcwg-bot/tcwg_gcc_build--master-arm success Build passed

Commit Message

Alex Coplan Aug. 1, 2024, 9:16 a.m. UTC 
  This extends GCC's GDB hooks to attempt invoking the user-defined
command "on-gcc-hooks-load".  The idea is that users can define the
command in their .gdbinit to override the default values of parameters
defined by GCC's GDB extensions.

For example, together with the previous patch, I can add the following
fragment to my .gdbinit:

define on-gcc-hooks-load
  set gcc-dot-cmd xdot
end

which means, once the GCC extensions get loaded, whenever I invoke
dot-fn then the graph will be rendered using xdot.

The try/except should make this patch a no-op for users that don't
currently define this command.  I looked for a way to test explicitly
for whether a GDB command exists but didn't find one.

This is needed because the user's .gdbinit is sourced before GCC's GDB
extensions are loaded, and GCC-specific parameters can't be configured
before they are defined.

As an alternative (to avoid having the callback), I considered having
the user define a convenience variable with a well-known name and using
that (if defined) in gdbhooks.py to set the default value for
gcc-dot-cmd.  But that seemed like a hack.  I'd be interested to hear
from any GDB experts if there's a better way of managing configuration
like this.

Tested by invoking dot-fn with/without the above fragment in my .gdbinit
and observing the change in dot renderer.

OK to install?

Thanks,
Alex

gcc/ChangeLog:

	* gdbhooks.py: Add attempted call to "on-gcc-hooks-load" once
	we've finished loading the hooks.
diff mbox series

Patch

diff --git a/gcc/gdbhooks.py b/gcc/gdbhooks.py
index db8ce0d071b..7a64c03b8ac 100644
--- a/gcc/gdbhooks.py
+++ b/gcc/gdbhooks.py
@@ -865,4 +865,12 @@  class DotFn(gdb.Command):
 
 DotFn()
 
+# Try and invoke the user-defined command "on-gcc-hooks-load".  Doing
+# this allows users to customize the GCC extensions once they've been
+# loaded by defining the hook in their .gdbinit.
+try:
+    gdb.execute('on-gcc-hooks-load')
+except gdb.error:
+    pass
+
 print('Successfully loaded GDB hooks for GCC')