gecko-dev/servo/etc/servo_gdb.py
Corey Farwell 5ddbba3c32 servo: Merge #6279 - Add flake8 to the tidy process for Python files (from frewsxcv:flake8); r=jdm
Fixes #6236

Also included in this commit are the changes need to make flake8 pass
for the existing python file

Source-Repo: https://github.com/servo/servo
Source-Revision: ccfe29d8f284dedc0101045d574a98fb1f69aa62
2015-06-04 10:41:36 -05:00

153 lines
4.2 KiB
Python

# Copyright 2013 The Servo Project Developers. See the COPYRIGHT
# file at the top-level directory of this distribution.
#
# Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
# http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
# <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
# option. This file may not be copied, modified, or distributed
# except according to those terms.
"""
A set of simple pretty printers for gdb to make debugging Servo a bit easier.
To load these, you need to add something like the following to your .gdbinit file:
python
import sys
sys.path.insert(0, '/home/<path to git checkout>/servo/src/etc')
import servo_gdb
servo_gdb.register_printers(None)
end
"""
import gdb
# Print Au in both raw value and CSS pixels
class AuPrinter:
def __init__(self, val):
self.val = val
def to_string(self):
i32_type = gdb.lookup_type("i32")
au = self.val.cast(i32_type)
return "{0}px".format(au / 60.0)
# Print a U8 bitfield as binary
class BitFieldU8Printer:
def __init__(self, val):
self.val = val
def to_string(self):
u8_type = gdb.lookup_type("u8")
value = self.val.cast(u8_type)
return "[{0:#010b}]".format(int(value))
# Print a struct with fields as children
class ChildPrinter:
def __init__(self, val):
self.val = val
def children(self):
children = []
for f in self.val.type.fields():
children.append((f.name, self.val[f.name]))
return children
def to_string(self):
return None
# Allow a trusted node to be dereferenced in the debugger
class TrustedNodeAddressPrinter:
def __init__(self, val):
self.val = val
def children(self):
node_type = gdb.lookup_type("struct script::dom::node::Node").pointer()
value = self.val.cast(node_type)
return [('Node', value)]
def to_string(self):
return self.val.address
# Extract a node type ID from enum
class NodeTypeIdPrinter:
def __init__(self, val):
self.val = val
def to_string(self):
u8_ptr_type = gdb.lookup_type("u8").pointer()
enum_0 = self.val.address.cast(u8_ptr_type).dereference()
enum_type = self.val.type.fields()[int(enum_0)].type
return str(enum_type).lstrip('struct ')
# Printer for std::Option<>
class OptionPrinter:
def __init__(self, val):
self.val = val
def is_some(self):
# Get size of discriminator
d_size = self.val.type.fields()[0].type.sizeof
if d_size > 0 and d_size <= 8:
# Read first byte to check if None or Some
ptr = self.val.address.cast(gdb.lookup_type("unsigned char").pointer())
discriminator = int(ptr.dereference())
return discriminator != 0
raise "unhandled discriminator size"
def children(self):
if self.is_some():
option_type = self.val.type
# Get total size and size of value
ptr = self.val.address.cast(gdb.lookup_type("unsigned char").pointer())
t_size = option_type.sizeof
value_type = option_type.fields()[1].type.fields()[1].type
v_size = value_type.sizeof
data_ptr = (ptr + t_size - v_size).cast(value_type.pointer()).dereference()
return [('Some', data_ptr)]
return [('None', None)]
def to_string(self):
return None
# Useful for debugging when type is unknown
class TestPrinter:
def __init__(self, val):
self.val = val
def to_string(self):
return "[UNKNOWN - type = {0}]".format(str(self.val.type))
type_map = [
('struct Au', AuPrinter),
('FlowFlags', BitFieldU8Printer),
('IntrinsicWidths', ChildPrinter),
('PlacementInfo', ChildPrinter),
('TrustedNodeAddress', TrustedNodeAddressPrinter),
('NodeTypeId', NodeTypeIdPrinter),
('Option', OptionPrinter),
]
def lookup_servo_type(val):
val_type = str(val.type)
for (type_name, printer) in type_map:
if val_type == type_name or val_type.endswith("::" + type_name):
return printer(val)
return None
# return TestPrinter(val)
def register_printers(obj):
gdb.pretty_printers.append(lookup_servo_type)