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import argparse
import textwrap
# usage: [-h] [-a | --all | --no-all] [-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
# -a, --all, --no-all dump all frames
# -s STACK_SIZE, --stack-size STACK_SIZE
# override stack_size (useful for JIT frames)
class CFP(gdb.Command):
FRAME_MAGICS = [
# frame types
'VM_FRAME_MAGIC_METHOD',
'VM_FRAME_MAGIC_BLOCK',
'VM_FRAME_MAGIC_CLASS',
'VM_FRAME_MAGIC_TOP',
'VM_FRAME_MAGIC_CFUNC',
'VM_FRAME_MAGIC_IFUNC',
'VM_FRAME_MAGIC_EVAL',
'VM_FRAME_MAGIC_RESCUE',
'VM_FRAME_MAGIC_DUMMY',
]
FRAME_FLAGS = [
# frame flag
'VM_FRAME_FLAG_FINISH',
'VM_FRAME_FLAG_BMETHOD',
'VM_FRAME_FLAG_CFRAME',
'VM_FRAME_FLAG_LAMBDA',
'VM_FRAME_FLAG_MODIFIED_BLOCK_PARAM',
'VM_FRAME_FLAG_CFRAME_KW',
'VM_FRAME_FLAG_PASSED',
# env flag
'VM_ENV_FLAG_LOCAL',
'VM_ENV_FLAG_ESCAPED',
'VM_ENV_FLAG_WB_REQUIRED',
'VM_ENV_FLAG_ISOLATED',
]
def __init__(self):
super(CFP, self).__init__('cfp', gdb.COMMAND_USER)
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('-a', '--all', action=argparse.BooleanOptionalAction, help='dump all frames')
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_index = int((end_cfp - self.get_int(cfp) - 1) / self.get_int('sizeof(rb_control_frame_t)'))
if args.all:
cfp_count = int((end_cfp - self.get_int('ruby_current_ec->cfp')) / self.get_int('sizeof(rb_control_frame_t)')) - 1 # exclude dummy CFP
for i in range(cfp_count):
print('-' * 80)
self.invoke(str(cfp_count - i - 1), from_tty)
return
print('CFP (addr=0x{:x}, index={}):'.format(self.get_int(cfp), cfp_index))
gdb.execute(f'p *({cfp})')
print()
if self.get_int(f'{cfp}->iseq'):
local_size = self.get_int(f'{cfp}->iseq->body->local_table_size - {cfp}->iseq->body->param.size')
param_size = self.get_int(f'{cfp}->iseq->body->param.size')
if local_size:
print(f'Params (size={param_size}):')
for i in range(-3 - local_size - param_size, -3 - local_size):
self.print_stack(cfp, i, self.rp(cfp, i))
print()
if param_size:
print(f'Locals (size={local_size}):')
for i in range(-3 - local_size, -3):
self.print_stack(cfp, i, self.rp(cfp, i))
print()
print('Env:')
self.print_env(cfp, -3, self.rp_env(cfp, -3))
self.print_env(cfp, -2, self.specval(cfp, -2))
self.print_env(cfp, -1, self.frame_types(cfp, -1))
print()
# We can't calculate BP for the first frame.
# vm_base_ptr doesn't work for C frames either.
if cfp_index > 0 and self.get_int(f'{cfp}->iseq'):
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))
print(self.regs(cfp, stack_size))
def print_env(self, cfp, bp_index, content):
ep_index = bp_index + 1
address = self.get_int(f'((rb_control_frame_t *){cfp})->ep + {ep_index}')
value = self.get_env(cfp, bp_index)
regs = self.regs(cfp, bp_index)
if content:
content = textwrap.indent(content, ' ' * 3).lstrip() # Leave the regs column empty
content = f'{content} '
print('{:2} 0x{:x} [{}] {}(0x{:x})'.format(regs, address, bp_index, content, value))
def print_stack(self, cfp, bp_index, content):
address = self.get_int(f'vm_base_ptr({cfp}) + {bp_index}')
value = self.get_value(cfp, bp_index)
regs = self.regs(cfp, bp_index)
if content:
content = textwrap.indent(content, ' ' * 3).lstrip() # Leave the regs column empty
content = f'{content} '
print('{:2} 0x{:x} [{}] {}(0x{:x})'.format(regs, address, bp_index, content, value))
def regs(self, cfp, bp_index):
address = self.get_int(f'vm_base_ptr({cfp}) + {bp_index}')
regs = []
for reg, field in { 'EP': 'ep', 'SP': 'sp' }.items():
if address == self.get_int(f'{cfp}->{field}'):
regs.append(reg)
return ' '.join(regs)
def rp(self, cfp, bp_index):
value = self.get_value(cfp, bp_index)
return self.get_string(f'rp {value}').rstrip()
def rp_env(self, cfp, bp_index):
value = self.get_env(cfp, bp_index)
return self.get_string(f'rp {value}').rstrip()
# specval: block_handler or previous EP
def specval(self, cfp, bp_index):
value = self.get_env(cfp, bp_index)
if value == 0:
return 'VM_BLOCK_HANDLER_NONE'
if value == self.get_int('rb_block_param_proxy'):
return 'rb_block_param_proxy'
return ''
def frame_types(self, cfp, bp_index):
types = []
value = self.get_env(cfp, bp_index)
magic_mask = self.get_int('VM_FRAME_MAGIC_MASK')
for magic in self.FRAME_MAGICS:
magic_value = self.get_int(magic)
if value & magic_mask == magic_value:
types.append(magic)
for flag in self.FRAME_FLAGS:
flag_value = self.get_int(flag)
if value & flag_value:
types.append(flag)
return ' | '.join(types)
def get_env(self, cfp, bp_index):
ep_index = bp_index + 1
return self.get_int(f'((rb_control_frame_t *){cfp})->ep[{ep_index}]')
def get_value(self, cfp, bp_index):
return self.get_int(f'vm_base_ptr({cfp})[{bp_index}]')
def get_int(self, expr):
return int(self.get_string(f'printf "%ld", ({expr})'))
def get_string(self, expr):
return gdb.execute(expr, to_string=True)
CFP()
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