Commit 46ed89b7 authored by Luuk van Dijk's avatar Luuk van Dijk

runtime: gdb support: gracefully handle not being able to find types

The Dwarf info has the full typenames, the go *struct runtime.commonType
has the short name.  A more permanent fix would link the two together
but this way the user gets useable stack traces for now.

R=rsc
CC=golang-dev
https://golang.org/cl/5097046
parent 7249fa77
......@@ -187,6 +187,8 @@ def lookup_type(name):
def iface_dtype(obj):
"Decode type of the data field of an eface or iface struct."
# known issue: dtype_name decoded from runtime.commonType is "nested.Foo"
# but the dwarf table lists it as "full/path/to/nested.Foo"
if is_iface(obj):
go_type_ptr = obj['tab']['_type']
......@@ -198,13 +200,30 @@ def iface_dtype(obj):
ct = gdb.lookup_type("struct runtime.commonType").pointer()
dynamic_go_type = go_type_ptr['ptr'].cast(ct).dereference()
dtype_name = dynamic_go_type['string'].dereference()['str'].string()
type_size = int(dynamic_go_type['size'])
uintptr_size = int(dynamic_go_type['size'].type.sizeof) # size is itself an uintptr
dynamic_gdb_type = lookup_type(dtype_name)
if type_size > uintptr_size:
dynamic_gdb_type = dynamic_gdb_type.pointer()
if dynamic_gdb_type:
type_size = int(dynamic_go_type['size'])
uintptr_size = int(dynamic_go_type['size'].type.sizeof) # size is itself an uintptr
if type_size > uintptr_size:
dynamic_gdb_type = dynamic_gdb_type.pointer()
return dynamic_gdb_type
def iface_dtype_name(obj):
"Decode type name of the data field of an eface or iface struct."
if is_iface(obj):
go_type_ptr = obj['tab']['_type']
elif is_eface(obj):
go_type_ptr = obj['_type']
else:
return
ct = gdb.lookup_type("struct runtime.commonType").pointer()
dynamic_go_type = go_type_ptr['ptr'].cast(ct).dereference()
return dynamic_go_type['string'].dereference()['str'].string()
class IfacePrinter:
"""Pretty print interface values
......@@ -224,6 +243,10 @@ class IfacePrinter:
dtype = iface_dtype(self.val)
except:
return "<bad dynamic type>"
if not dtype: # trouble looking up, print something reasonable
return "(%s)%s" % (iface_dtype_name(self.val), self.val['data'])
try:
return self.val['data'].cast(dtype).dereference()
except:
......
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