scripts: gdb: Added some useful GDB scripts to test.py --gdb

These just invoke the existing dbg*.py python scripts, but allow quick
references to variables in the debugginged process:

  (gdb) dbgflags o file->b.o.flags
  LFS3_O_RDWR    0x00000002  Open a file as read and write
  LFS3_o_REG     0x10000000  Type = regular-file
  LFS3_o_UNSYNC  0x01000000  File's metadata does not match disk

Quite neat and useful!

This works by injecting dbg.gdb.py via gdb -x, which includes the
necessary python hooks to add these commands to gdb. This can be
overridden/extended with test.py/bench.py's --gdb-script flag.

Currently limited to scripts that seem the most useful for process
internals:

- dbgerr - Decode littlefs error codes
- dbgflags - Decode littlefs flags
- dbgtag - Decode littlefs tags

scripts/bench.py

@@ -40,6 +40,7 @@ RUNNER_PATH = ['./runners/bench_runner']
 HEADER_PATH = 'runners/bench_runner.h'
 
 GDB_PATH = ['gdb']
+GDB_SCRIPTS = ['./scripts/dbg.gdb.py']
 VALGRIND_PATH = ['valgrind']
 PERF_SCRIPT = ['./scripts/perf.py']
 
@@ -1469,12 +1470,16 @@ def run(runner, bench_ids=[], **args):
             or args.get('gdb_main')):
         failure = failures[0]
         cmd = find_runner(runner, failure.id, **args)
+        gdb_path = args['gdb_path']
+        gdb_scripts = (args.get('gdb_script') or GDB_SCRIPTS)
 
         if args.get('gdb_main'):
             # we don't really need the case breakpoint here, but it
             # can be helpful
             path, lineno = find_path(runner, failure.id, **args)
-            cmd[:0] = args['gdb_path'] + [
+            cmd[:0] = [
+                    *gdb_path,
+                    *it.chain.from_iterable(['-x', s] for s in gdb_scripts),
                     '-q',
                     '-ex', 'break main',
                     '-ex', 'break %s:%d' % (path, lineno),
@@ -1482,13 +1487,17 @@ def run(runner, bench_ids=[], **args):
                     '--args']
         elif args.get('gdb_perm'):
             path, lineno = find_path(runner, failure.id, **args)
-            cmd[:0] = args['gdb_path'] + [
+            cmd[:0] = [
+                    *gdb_path,
+                    *it.chain.from_iterable(['-x', s] for s in gdb_scripts),
                     '-q',
                     '-ex', 'break %s:%d' % (path, lineno),
                     '-ex', 'run',
                     '--args']
         else:
-            cmd[:0] = args['gdb_path'] + [
+            cmd[:0] = [
+                    *gdb_path,
+                    *it.chain.from_iterable(['-x', s] for s in gdb_scripts),
                     '-q',
                     '-ex', 'run',
                     '--args']
@@ -1693,6 +1702,11 @@ if __name__ == "__main__":
             default=GDB_PATH,
             help="Path to the gdb executable, may include flags. "
                 "Defaults to %r." % GDB_PATH)
+    bench_parser.add_argument(
+            '--gdb-script',
+            action='append',
+            help="Paths to scripts to execute when dropping into gdb. "
+                "Defaults to %r." % GDB_SCRIPTS)
     bench_parser.add_argument(
             '-e', '--exec',
             type=lambda e: e.split(),

scripts/dbg.gdb.py

@@ -0,0 +1,97 @@
+#
+# hooks for gdb:
+# (gdb) source ./scripts/dbg.gdb.py
+#
+#
+
+
+# dbgerr
+class DbgErr(gdb.Command):
+    """Decode littlefs error codes. See -h/--help for more info."""
+
+    def __init__(self):
+        super().__init__("dbgerr",
+                gdb.COMMAND_DATA,
+                gdb.COMPLETE_EXPRESSION)
+
+    def invoke(self, args, *_):
+        args = args.split()
+        # find nonflags
+        nonflags = []
+        for i, a in enumerate(args):
+            if not a.startswith('-'):
+                nonflags.append(i)
+        # parse and eval
+        for i, n in enumerate(nonflags):
+            try:
+                args[n] = '%d' % gdb.parse_and_eval(args[n])
+            except gdb.error as e:
+                raise gdb.GdbError(e)
+
+        # execute
+        gdb.execute(' '.join(['!./scripts/dbgerr.py'] + args))
+
+DbgErr()
+
+
+# dbgflags
+class DbgFlags(gdb.Command):
+    """Decode littlefs flags. See -h/--help for more info."""
+
+    def __init__(self):
+        super().__init__("dbgflags",
+                gdb.COMMAND_DATA,
+                gdb.COMPLETE_EXPRESSION)
+
+    def invoke(self, args, *_):
+        args = args.split()
+        # hack, but don't eval if -l or --list specified
+        if '-l' not in args and '--list' not in args:
+            # find nonflags
+            nonflags = []
+            for i, a in enumerate(args):
+                if not a.startswith('-'):
+                    nonflags.append(i)
+            # parse and eval
+            for i, n in enumerate(nonflags):
+                # dbgflags is special in that first arg may be prefix
+                if i > 0 or len(nonflags) <= 1:
+                    try:
+                        args[n] = '%d' % gdb.parse_and_eval(args[n])
+                    except gdb.error as e:
+                        raise gdb.GdbError(e)
+
+        # execute
+        gdb.execute(' '.join(['!./scripts/dbgflags.py'] + args))
+
+DbgFlags()
+
+
+# dbgtag
+class DbgTag(gdb.Command):
+    """Decode littlefs tags. See -h/--help for more info."""
+
+    def __init__(self):
+        super().__init__("dbgtag",
+                gdb.COMMAND_DATA,
+                gdb.COMPLETE_EXPRESSION)
+
+    def invoke(self, args, *_):
+        args = args.split()
+        # find nonflags
+        nonflags = []
+        for i, a in enumerate(args):
+            if not a.startswith('-'):
+                nonflags.append(i)
+        # parse and eval
+        for i, n in enumerate(nonflags):
+            try:
+                args[n] = '%d' % gdb.parse_and_eval(args[n])
+            except gdb.error as e:
+                raise gdb.GdbError(e)
+
+        # execute
+        gdb.execute(' '.join(['!./scripts/dbgtag.py'] + args))
+
+DbgTag()
+

scripts/test.py

@@ -41,6 +41,7 @@ RUNNER_PATH = ['./runners/test_runner']
 HEADER_PATH = 'runners/test_runner.h'
 
 GDB_PATH = ['gdb']
+GDB_SCRIPTS = ['./scripts/dbg.gdb.py']
 VALGRIND_PATH = ['valgrind']
 PERF_SCRIPT = ['./scripts/perf.py']
 
@@ -1444,12 +1445,16 @@ def run(runner, test_ids=[], **args):
             or args.get('gdb_pl_after')):
         failure = failures[0]
         cmd = find_runner(runner, failure.id, **args)
+        gdb_path = args['gdb_path']
+        gdb_scripts = (args.get('gdb_script') or GDB_SCRIPTS)
 
         if args.get('gdb_main'):
             # we don't really need the case breakpoint here, but it
             # can be helpful
             path, lineno = find_path(runner, failure.id, **args)
-            cmd[:0] = args['gdb_path'] + [
+            cmd[:0] = [
+                    *gdb_path,
+                    *it.chain.from_iterable(['-x', s] for s in gdb_scripts),
                     '-q',
                     '-ex', 'break main',
                     '-ex', 'break %s:%d' % (path, lineno),
@@ -1457,14 +1462,18 @@ def run(runner, test_ids=[], **args):
                     '--args']
         elif args.get('gdb_perm'):
             path, lineno = find_path(runner, failure.id, **args)
-            cmd[:0] = args['gdb_path'] + [
+            cmd[:0] = [
+                    *gdb_path,
+                    *it.chain.from_iterable(['-x', s] for s in gdb_scripts),
                     '-q',
                     '-ex', 'break %s:%d' % (path, lineno),
                     '-ex', 'run',
                     '--args']
         elif args.get('gdb_pl') is not None:
             path, lineno = find_path(runner, failure.id, **args)
-            cmd[:0] = args['gdb_path'] + [
+            cmd[:0] = [
+                    *gdb_path,
+                    *it.chain.from_iterable(['-x', s] for s in gdb_scripts),
                     '-q',
                     '-ex', 'break %s:%d' % (path, lineno),
                     '-ex', 'ignore 1 %d' % args['gdb_pl'],
@@ -1477,7 +1486,9 @@ def run(runner, test_ids=[], **args):
                             failure.id.split(':', 2)[-1]))
                         if failure.id.count(':') >= 2 else 0)
             path, lineno = find_path(runner, failure.id, **args)
-            cmd[:0] = args['gdb_path'] + [
+            cmd[:0] = [
+                    *gdb_path,
+                    *it.chain.from_iterable(['-x', s] for s in gdb_scripts),
                     '-q',
                     '-ex', 'break %s:%d' % (path, lineno),
                     '-ex', 'ignore 1 %d' % max(powerlosses-1, 0),
@@ -1490,14 +1501,18 @@ def run(runner, test_ids=[], **args):
                             failure.id.split(':', 2)[-1]))
                         if failure.id.count(':') >= 2 else 0)
             path, lineno = find_path(runner, failure.id, **args)
-            cmd[:0] = args['gdb_path'] + [
+            cmd[:0] = [
+                    *gdb_path,
+                    *it.chain.from_iterable(['-x', s] for s in gdb_scripts),
                     '-q',
                     '-ex', 'break %s:%d' % (path, lineno),
                     '-ex', 'ignore 1 %d' % powerlosses,
                     '-ex', 'run',
                     '--args']
         else:
-            cmd[:0] = args['gdb_path'] + [
+            cmd[:0] = [
+                    *gdb_path,
+                    *it.chain.from_iterable(['-x', s] for s in gdb_scripts),
                     '-q',
                     '-ex', 'run',
                     '--args']
@@ -1722,6 +1737,11 @@ if __name__ == "__main__":
             default=GDB_PATH,
             help="Path to the gdb executable, may include flags. "
                 "Defaults to %r." % GDB_PATH)
+    test_parser.add_argument(
+            '--gdb-script',
+            action='append',
+            help="Paths to scripts to execute when dropping into gdb. "
+                "Defaults to %r." % GDB_SCRIPTS)
     test_parser.add_argument(
             '-e', '--exec',
             type=lambda e: e.split(),