misc/gdb.py: Allow overriding stack_size [ci skip]

misc/gdb.py

@@ -1,8 +1,17 @@
+import argparse
 import textwrap
 
-# Usage:
-#   cfp: Dump the current cfp
-#   cfp 1: Dump the caller cfp
+# usage: [-h] [-s STACK_SIZE] [uplevel]
+#
+# Dump a control frame
+#
+# positional arguments:
+#   uplevel               CFP offset from the stack top
+#
+# options:
+#   -h, --help            show this help message and exit
+#   -s STACK_SIZE, --stack-size STACK_SIZE
+#                         override stack_size (useful for JIT frames)
 class CFP(gdb.Command):
     FRAME_MAGICS = [
         # frame types
@@ -35,10 +44,16 @@ class CFP(gdb.Command):
     def __init__(self):
         super(CFP, self).__init__('cfp', gdb.COMMAND_USER)
 
-    def invoke(self, offset, from_tty):
-        if not offset:
-            offset = '0'
-        cfp = f'(ruby_current_ec->cfp + ({offset}))'
+        self.parser = argparse.ArgumentParser(description='Dump a control frame')
+        self.parser.add_argument('uplevel', type=int, nargs='?', default=0, help='CFP offset from the stack top')
+        self.parser.add_argument('-s', '--stack-size', type=int, help='override stack_size (useful for JIT frames)')
+
+    def invoke(self, args, from_tty):
+        try:
+            args = self.parser.parse_args(args.split())
+        except SystemExit:
+            return
+        cfp = f'(ruby_current_ec->cfp + ({args.uplevel}))'
 
         end_cfp = self.get_int('ruby_current_ec->vm_stack + ruby_current_ec->vm_stack_size')
         cfp_count = int((end_cfp - self.get_int('ruby_current_ec->cfp')) / self.get_int('sizeof(rb_control_frame_t)'))
@@ -65,7 +80,10 @@ def invoke(self, offset, from_tty):
         self.print_stack(cfp, -1, self.frame_types(cfp, -1))
         print()
 
-        stack_size = int((self.get_int(f'{cfp}->sp') - self.get_int(f'vm_base_ptr({cfp})')) / 8)
+        if args.stack_size is not None:
+            stack_size = args.stack_size
+        else:
+            stack_size = int((self.get_int(f'{cfp}->sp') - self.get_int(f'vm_base_ptr({cfp})')) / 8)
         print(f'Stack (size={stack_size}):')
         for i in range(0, stack_size):
             self.print_stack(cfp, i, self.rp(cfp, i))