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# This Source Code Form is subject to the terms of the Mozilla Public
# License, v. 2.0. If a copy of the MPL was not distributed with this file,
# Pretty-printers for JSOp and jsbytecode values.
import gdb
import gdb.types
import mozilla.prettyprinters
from mozilla.prettyprinters import pretty_printer, ptr_pretty_printer
# Forget any printers from previous loads of this module.
mozilla.prettyprinters.clear_module_printers(__name__)
class JSOpTypeCache(object):
# Cache information about the JSOp type for this objfile.
def __init__(self, cache):
self.tJSOp = gdb.lookup_type("JSOp")
@classmethod
def get_or_create(cls, cache):
if not cache.mod_JSOp:
cache.mod_JSOp = cls(cache)
return cache.mod_JSOp
@pretty_printer("JSOp")
class JSOp(object):
def __init__(self, value, cache):
self.value = value
self.cache = cache
self.jotc = JSOpTypeCache.get_or_create(cache)
def to_string(self):
# JSOp's storage type is |uint8_t|, but gdb uses a signed value.
# Manually convert it to an unsigned value.
#
idx = int(self.value.cast(self.jotc.tJSOp.target()))
assert 0 <= idx and idx <= 255
fields = self.jotc.tJSOp.fields()
if idx < len(fields):
return fields[idx].name
return "(JSOp) {:d}".format(idx)
@ptr_pretty_printer("jsbytecode")
class JSBytecodePtr(mozilla.prettyprinters.Pointer):
def __init__(self, value, cache):
super(JSBytecodePtr, self).__init__(value, cache)
self.jotc = JSOpTypeCache.get_or_create(cache)
def to_string(self):
try:
opcode = str(self.value.dereference().cast(self.jotc.tJSOp))
except Exception:
opcode = "bad pc"
return "{} ({})".format(self.value.cast(self.cache.void_ptr_t), opcode)