mirror of
https://github.com/golang/go
synced 2024-11-20 02:24:43 -07:00
3fbd478a8a
also, a few miscellaneous fixes to files outside pkg R=golang-dev, dsymonds, mikioh.mikioh, r CC=golang-dev https://golang.org/cl/4517116
401 lines
9.8 KiB
Python
401 lines
9.8 KiB
Python
# Copyright 2010 The Go Authors. All rights reserved.
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# Use of this source code is governed by a BSD-style
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# license that can be found in the LICENSE file.
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"""GDB Pretty printers and convenience functions for Go's runtime structures.
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This script is loaded by GDB when it finds a .debug_gdb_scripts
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section in the compiled binary. The [68]l linkers emit this with a
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path to this file based on the path to the runtime package.
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"""
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# Known issues:
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# - pretty printing only works for the 'native' strings. E.g. 'type
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# foo string' will make foo a plain struct in the eyes of gdb,
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# circumventing the pretty print triggering.
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import sys, re
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print >>sys.stderr, "Loading Go Runtime support."
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# allow to manually reload while developing
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goobjfile = gdb.current_objfile() or gdb.objfiles()[0]
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goobjfile.pretty_printers = []
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#
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# Pretty Printers
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#
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class StringTypePrinter:
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"Pretty print Go strings."
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pattern = re.compile(r'^struct string$')
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def __init__(self, val):
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self.val = val
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def display_hint(self):
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return 'string'
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def to_string(self):
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l = int(self.val['len'])
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return self.val['str'].string("utf-8", "ignore", l)
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class SliceTypePrinter:
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"Pretty print slices."
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pattern = re.compile(r'^struct \[\]')
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def __init__(self, val):
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self.val = val
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def display_hint(self):
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return 'array'
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def to_string(self):
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return str(self.val.type)[6:] # skip 'struct '
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def children(self):
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ptr = self.val["array"]
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for idx in range(self.val["len"]):
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yield ('[%d]' % idx, (ptr + idx).dereference())
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class MapTypePrinter:
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"""Pretty print map[K]V types.
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Map-typed go variables are really pointers. dereference them in gdb
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to inspect their contents with this pretty printer.
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"""
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pattern = re.compile(r'^struct hash<.*>$')
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def __init__(self, val):
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self.val = val
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def display_hint(self):
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return 'map'
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def to_string(self):
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return str(self.val.type)
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def children(self):
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stab = self.val['st']
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i = 0
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for v in self.traverse_hash(stab):
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yield ("[%d]" % i, v['key'])
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yield ("[%d]" % (i + 1), v['val'])
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i += 2
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def traverse_hash(self, stab):
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ptr = stab['entry'].address
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end = stab['end']
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while ptr < end:
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v = ptr.dereference()
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ptr = ptr + 1
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if v['hash'] == 0: continue
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if v['hash'] & 63 == 63: # subtable
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for v in self.traverse_hash(v['key'].cast(self.val['st'].type)):
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yield v
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else:
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yield v
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class ChanTypePrinter:
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"""Pretty print chan[T] types.
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Chan-typed go variables are really pointers. dereference them in gdb
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to inspect their contents with this pretty printer.
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"""
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pattern = re.compile(r'^struct hchan<.*>$')
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def __init__(self, val):
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self.val = val
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def display_hint(self):
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return 'array'
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def to_string(self):
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return str(self.val.type)
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def children(self):
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# see chan.c chanbuf()
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et = [x.type for x in self.val['free'].type.target().fields() if x.name == 'elem'][0]
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ptr = (self.val.address + 1).cast(et.pointer())
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for i in range(self.val["qcount"]):
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j = (self.val["recvx"] + i) % self.val["dataqsiz"]
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yield ('[%d]' % i, (ptr + j).dereference())
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#
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# Register all the *Printer classes above.
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#
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def makematcher(klass):
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def matcher(val):
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try:
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if klass.pattern.match(str(val.type)):
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return klass(val)
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except:
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pass
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return matcher
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goobjfile.pretty_printers.extend([makematcher(k) for k in vars().values() if hasattr(k, 'pattern')])
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#
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# For reference, this is what we're trying to do:
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# eface: p *(*(struct 'runtime.commonType'*)'main.e'->type_->data)->string
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# iface: p *(*(struct 'runtime.commonType'*)'main.s'->tab->Type->data)->string
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#
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# interface types can't be recognized by their name, instead we check
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# if they have the expected fields. Unfortunately the mapping of
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# fields to python attributes in gdb.py isn't complete: you can't test
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# for presence other than by trapping.
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def is_iface(val):
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try:
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return str(val['tab'].type) == "struct runtime.itab *" \
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and str(val['data'].type) == "void *"
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except:
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pass
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def is_eface(val):
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try:
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return str(val['_type'].type) == "struct runtime._type *" \
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and str(val['data'].type) == "void *"
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except:
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pass
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def lookup_type(name):
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try:
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return gdb.lookup_type(name)
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except:
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pass
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try:
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return gdb.lookup_type('struct ' + name)
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except:
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pass
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try:
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return gdb.lookup_type('struct ' + name[1:]).pointer()
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except:
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pass
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def iface_dtype(obj):
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"Decode type of the data field of an eface or iface struct."
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if is_iface(obj):
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go_type_ptr = obj['tab']['_type']
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elif is_eface(obj):
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go_type_ptr = obj['_type']
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else:
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return
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ct = gdb.lookup_type("struct runtime.commonType").pointer()
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dynamic_go_type = go_type_ptr['ptr'].cast(ct).dereference()
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dtype_name = dynamic_go_type['string'].dereference()['str'].string()
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type_size = int(dynamic_go_type['size'])
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uintptr_size = int(dynamic_go_type['size'].type.sizeof) # size is itself an uintptr
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dynamic_gdb_type = lookup_type(dtype_name)
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if type_size > uintptr_size:
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dynamic_gdb_type = dynamic_gdb_type.pointer()
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return dynamic_gdb_type
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class IfacePrinter:
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"""Pretty print interface values
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Casts the data field to the appropriate dynamic type."""
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def __init__(self, val):
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self.val = val
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def display_hint(self):
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return 'string'
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def to_string(self):
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if self.val['data'] == 0:
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return 0x0
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try:
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dtype = iface_dtype(self.val)
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except:
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return "<bad dynamic type>"
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try:
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return self.val['data'].cast(dtype).dereference()
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except:
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pass
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return self.val['data'].cast(dtype)
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def ifacematcher(val):
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if is_iface(val) or is_eface(val):
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return IfacePrinter(val)
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goobjfile.pretty_printers.append(ifacematcher)
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#
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# Convenience Functions
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#
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class GoLenFunc(gdb.Function):
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"Length of strings, slices, maps or channels"
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how = ((StringTypePrinter, 'len' ),
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(SliceTypePrinter, 'len'),
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(MapTypePrinter, 'count'),
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(ChanTypePrinter, 'qcount'))
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def __init__(self):
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super(GoLenFunc, self).__init__("len")
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def invoke(self, obj):
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typename = str(obj.type)
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for klass, fld in self.how:
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if klass.pattern.match(typename):
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return obj[fld]
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class GoCapFunc(gdb.Function):
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"Capacity of slices or channels"
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how = ((SliceTypePrinter, 'cap'),
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(ChanTypePrinter, 'dataqsiz'))
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def __init__(self):
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super(GoCapFunc, self).__init__("cap")
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def invoke(self, obj):
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typename = str(obj.type)
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for klass, fld in self.how:
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if klass.pattern.match(typename):
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return obj[fld]
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class DTypeFunc(gdb.Function):
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"""Cast Interface values to their dynamic type.
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For non-interface types this behaves as the identity operation.
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"""
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def __init__(self):
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super(DTypeFunc, self).__init__("dtype")
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def invoke(self, obj):
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try:
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return obj['data'].cast(iface_dtype(obj))
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except:
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pass
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return obj
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#
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# Commands
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#
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sts = ( 'idle', 'runnable', 'running', 'syscall', 'waiting', 'moribund', 'dead', 'recovery')
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def linked_list(ptr, linkfield):
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while ptr:
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yield ptr
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ptr = ptr[linkfield]
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class GoroutinesCmd(gdb.Command):
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"List all goroutines."
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def __init__(self):
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super(GoroutinesCmd, self).__init__("info goroutines", gdb.COMMAND_STACK, gdb.COMPLETE_NONE)
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def invoke(self, arg, from_tty):
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# args = gdb.string_to_argv(arg)
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vp = gdb.lookup_type('void').pointer()
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for ptr in linked_list(gdb.parse_and_eval("'runtime.allg'"), 'alllink'):
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if ptr['status'] == 6: # 'gdead'
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continue
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s = ' '
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if ptr['m']:
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s = '*'
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pc = ptr['sched']['pc'].cast(vp)
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sp = ptr['sched']['sp'].cast(vp)
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blk = gdb.block_for_pc(long((pc)))
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print s, ptr['goid'], "%8s" % sts[long((ptr['status']))], blk.function
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def find_goroutine(goid):
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vp = gdb.lookup_type('void').pointer()
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for ptr in linked_list(gdb.parse_and_eval("'runtime.allg'"), 'alllink'):
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if ptr['status'] == 6: # 'gdead'
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continue
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if ptr['goid'] == goid:
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return [ptr['sched'][x].cast(vp) for x in 'pc', 'sp']
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return None, None
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class GoroutineCmd(gdb.Command):
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"""Execute gdb command in the context of goroutine <goid>.
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Switch PC and SP to the ones in the goroutine's G structure,
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execute an arbitrary gdb command, and restore PC and SP.
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Usage: (gdb) goroutine <goid> <gdbcmd>
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Note that it is ill-defined to modify state in the context of a goroutine.
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Restrict yourself to inspecting values.
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"""
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def __init__(self):
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super(GoroutineCmd, self).__init__("goroutine", gdb.COMMAND_STACK, gdb.COMPLETE_NONE)
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def invoke(self, arg, from_tty):
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goid, cmd = arg.split(None, 1)
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pc, sp = find_goroutine(int(goid))
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if not pc:
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print "No such goroutine: ", goid
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return
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save_frame = gdb.selected_frame()
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gdb.parse_and_eval('$save_pc = $pc')
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gdb.parse_and_eval('$save_sp = $sp')
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gdb.parse_and_eval('$pc = 0x%x' % long(pc))
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gdb.parse_and_eval('$sp = 0x%x' % long(sp))
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try:
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gdb.execute(cmd)
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finally:
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gdb.parse_and_eval('$pc = $save_pc')
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gdb.parse_and_eval('$sp = $save_sp')
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save_frame.select()
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class GoIfaceCmd(gdb.Command):
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"Print Static and dynamic interface types"
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def __init__(self):
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super(GoIfaceCmd, self).__init__("iface", gdb.COMMAND_DATA, gdb.COMPLETE_SYMBOL)
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def invoke(self, arg, from_tty):
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for obj in gdb.string_to_argv(arg):
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try:
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#TODO fix quoting for qualified variable names
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obj = gdb.parse_and_eval("%s" % obj)
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except Exception, e:
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print "Can't parse ", obj, ": ", e
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continue
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dtype = iface_dtype(obj)
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if not dtype:
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print "Not an interface: ", obj.type
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continue
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print "%s: %s" % (obj.type, dtype)
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# TODO: print interface's methods and dynamic type's func pointers thereof.
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#rsc: "to find the number of entries in the itab's Fn field look at itab.inter->numMethods
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#i am sure i have the names wrong but look at the interface type and its method count"
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# so Itype will start with a commontype which has kind = interface
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#
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# Register all convenience functions and CLI commands
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#
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for k in vars().values():
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if hasattr(k, 'invoke'):
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k()
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