tasn pushed a commit to branch efl-1.16.
http://git.enlightenment.org/core/efl.git/commit/?id=34efbca16e954d994a26d730753b8fbd1d4a37ec
commit 34efbca16e954d994a26d730753b8fbd1d4a37ec
Author: Tom Hacohen <t...@stosb.com>
Date: Fri Nov 18 08:44:21 2016 +0000
Eo gdb: add a way to resolve Eo ids from GDB without a running process
This is a backport of 79d76fb25ece4ffbf5785b4be2b030f062ef9f2c.
Normally when debugging Eo with gdb you can just use any of the internal
eo functions to resolve the id to its internal pointer. However, when
loading a coredump you can't execute any code, not even the id resolve
code.
This change adds a gdb function that resolves the id to its pointer form
without executing any code in the process space. This plugin is
essentially the id resolve code written in python as a gdb function.
Usage:
Print the pointer:
(gdb) print $eo_resolve(obj)
$1 = (_Eo_Object *) 0x5555559bbe70
Use it directly (e.g. to print the class name):
(gdb) $eo_resolve(obj)->klass->desc.name
This plugin requires that the coredump would be loaded with the exact
same libeo.so binary (or at least one that hasn't changed eo internals),
and that the debug symbols for libeo.so would be available for gdb to
use.
@feature
---
data/eo/eo_gdb.py | 83 +++++++++++++++++++++++++++++++++++++++++++++++++++++--
1 file changed, 81 insertions(+), 2 deletions(-)
diff --git a/data/eo/eo_gdb.py b/data/eo/eo_gdb.py
index 2191210..e54797d 100644
--- a/data/eo/eo_gdb.py
+++ b/data/eo/eo_gdb.py
@@ -1,4 +1,83 @@
-# Implement eo_break that'll break on a macro/subid/whatever.
-
import gdb
+"""
+All of this script relies heavily on Eo internals and will break if they
+change. Need to make sure this is always in sync.
+"""
+
+ptr_size = int(gdb.parse_and_eval('sizeof(void *)'))
+
+if ptr_size == 4:
+ # 32 bits
+ BITS_MID_TABLE_ID = 5
+ BITS_TABLE_ID = 5
+ BITS_ENTRY_ID = 12
+ BITS_GENERATION_COUNTER = 9
+ REF_TAG_SHIFT = 31
+ DROPPED_TABLES = 0
+ DROPPED_ENTRIES = 4
+else:
+ # 64 bits
+ BITS_MID_TABLE_ID = 11
+ BITS_TABLE_ID = 11
+ BITS_ENTRY_ID = 12
+ BITS_GENERATION_COUNTER = 29
+ REF_TAG_SHIFT = 63
+ DROPPED_TABLES = 2
+ DROPPED_ENTRIES = 3
+
+# /* Shifts macros to manipulate the Eo id */
+SHIFT_MID_TABLE_ID = (BITS_TABLE_ID + BITS_ENTRY_ID + BITS_GENERATION_COUNTER)
+SHIFT_TABLE_ID = (BITS_ENTRY_ID + BITS_GENERATION_COUNTER)
+SHIFT_ENTRY_ID = (BITS_GENERATION_COUNTER)
+
+# /* Maximum ranges */
+MAX_MID_TABLE_ID = (1 << BITS_MID_TABLE_ID)
+MAX_TABLE_ID = ((1 << BITS_TABLE_ID) - DROPPED_TABLES)
+MAX_ENTRY_ID = ((1 << BITS_ENTRY_ID) - DROPPED_ENTRIES)
+MAX_GENERATIONS = (1 << BITS_GENERATION_COUNTER)
+
+# /* Masks */
+MASK_MID_TABLE_ID = (MAX_MID_TABLE_ID - 1)
+MASK_TABLE_ID = ((1 << BITS_TABLE_ID) - 1)
+MASK_ENTRY_ID = ((1 << BITS_ENTRY_ID) - 1)
+MASK_GENERATIONS = (MAX_GENERATIONS - 1)
+MASK_OBJ_TAG = (1 << (REF_TAG_SHIFT))
+
+
+null_ptr = gdb.parse_and_eval('(_Eo_Object *) 0')
+
+
+class Eo_resolve(gdb.Function):
+ def __init__(self):
+ gdb.Function.__init__(self, 'eo_resolve')
+
+ def invoke(self, arg):
+ obj_id = int(arg)
+
+ mid_table_id = (obj_id >> SHIFT_MID_TABLE_ID) & MASK_MID_TABLE_ID
+ table_id = (obj_id >> SHIFT_TABLE_ID) & MASK_TABLE_ID
+ entry_id = (obj_id >> SHIFT_ENTRY_ID) & MASK_ENTRY_ID
+ tag_bit = (obj_id) & MASK_OBJ_TAG
+ generation = obj_id & MASK_GENERATIONS
+
+ if (obj_id == 0) or (tag_bit == 0):
+ gdb.write('Pointer is NULL or not a valid object.\n')
+ return null_ptr
+
+ entries =
gdb.parse_and_eval('_eo_ids_tables[{0}]'.format(mid_table_id))
+
+ if int(entries) == 0:
+ gdb.write('Pointer is not a valid object.\n')
+ return null_ptr
+
+ entry = entries[table_id]['entries'][entry_id]
+
+ if (not entry['active']) or (int(entry['generation']) != generation):
+ gdb.write('Pointer is no longer active.\n')
+ return null_ptr
+
+ return entry['ptr']
+
+
+Eo_resolve()
--
