480 lines
16 KiB
Python
480 lines
16 KiB
Python
# Python hooks for gdb for debugging GCC
|
|
# Copyright (C) 2013-2014 Free Software Foundation, Inc.
|
|
|
|
# Contributed by David Malcolm <dmalcolm@redhat.com>
|
|
|
|
# This file is part of GCC.
|
|
|
|
# GCC is free software; you can redistribute it and/or modify it under
|
|
# the terms of the GNU General Public License as published by the Free
|
|
# Software Foundation; either version 3, or (at your option) any later
|
|
# version.
|
|
|
|
# GCC is distributed in the hope that it will be useful, but WITHOUT
|
|
# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
|
|
# FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
|
|
# for more details.
|
|
|
|
# You should have received a copy of the GNU General Public License
|
|
# along with GCC; see the file COPYING3. If not see
|
|
# <http://www.gnu.org/licenses/>.
|
|
|
|
"""
|
|
Enabling the debugging hooks
|
|
----------------------------
|
|
gcc/configure (from configure.ac) generates a .gdbinit within the "gcc"
|
|
subdirectory of the build directory, and when run by gdb, this imports
|
|
gcc/gdbhooks.py from the source directory, injecting useful Python code
|
|
into gdb.
|
|
|
|
You may see a message from gdb of the form:
|
|
"path-to-build/gcc/.gdbinit" auto-loading has been declined by your `auto-load safe-path'
|
|
as a protection against untrustworthy python scripts. See
|
|
http://sourceware.org/gdb/onlinedocs/gdb/Auto_002dloading-safe-path.html
|
|
|
|
The fix is to mark the paths of the build/gcc directory as trustworthy.
|
|
An easy way to do so is by adding the following to your ~/.gdbinit script:
|
|
add-auto-load-safe-path /absolute/path/to/build/gcc
|
|
for the build directories for your various checkouts of gcc.
|
|
|
|
If it's working, you should see the message:
|
|
Successfully loaded GDB hooks for GCC
|
|
as gdb starts up.
|
|
|
|
During development, I've been manually invoking the code in this way, as a
|
|
precanned way of printing a variety of different kinds of value:
|
|
|
|
gdb \
|
|
-ex "break expand_gimple_stmt" \
|
|
-ex "run" \
|
|
-ex "bt" \
|
|
--args \
|
|
./cc1 foo.c -O3
|
|
|
|
Examples of output using the pretty-printers
|
|
--------------------------------------------
|
|
Pointer values are generally shown in the form:
|
|
<type address extra_info>
|
|
|
|
For example, an opt_pass* might appear as:
|
|
(gdb) p pass
|
|
$2 = <opt_pass* 0x188b600 "expand"(170)>
|
|
|
|
The name of the pass is given ("expand"), together with the
|
|
static_pass_number.
|
|
|
|
Note that you can dereference the pointer in the normal way:
|
|
(gdb) p *pass
|
|
$4 = {type = RTL_PASS, name = 0x120a312 "expand",
|
|
[etc, ...snipped...]
|
|
|
|
and you can suppress pretty-printers using /r (for "raw"):
|
|
(gdb) p /r pass
|
|
$3 = (opt_pass *) 0x188b600
|
|
|
|
Basic blocks are shown with their index in parentheses, apart from the
|
|
CFG's entry and exit blocks, which are given as "ENTRY" and "EXIT":
|
|
(gdb) p bb
|
|
$9 = <basic_block 0x7ffff041f1a0 (2)>
|
|
(gdb) p cfun->cfg->x_entry_block_ptr
|
|
$10 = <basic_block 0x7ffff041f0d0 (ENTRY)>
|
|
(gdb) p cfun->cfg->x_exit_block_ptr
|
|
$11 = <basic_block 0x7ffff041f138 (EXIT)>
|
|
|
|
CFG edges are shown with the src and dest blocks given in parentheses:
|
|
(gdb) p e
|
|
$1 = <edge 0x7ffff043f118 (ENTRY -> 6)>
|
|
|
|
Tree nodes are printed using Python code that emulates print_node_brief,
|
|
running in gdb, rather than in the inferior:
|
|
(gdb) p cfun->decl
|
|
$1 = <function_decl 0x7ffff0420b00 foo>
|
|
For usability, the type is printed first (e.g. "function_decl"), rather
|
|
than just "tree".
|
|
|
|
RTL expressions use a kludge: they are pretty-printed by injecting
|
|
calls into print-rtl.c into the inferior:
|
|
Value returned is $1 = (note 9 8 10 [bb 3] NOTE_INSN_BASIC_BLOCK)
|
|
(gdb) p $1
|
|
$2 = (note 9 8 10 [bb 3] NOTE_INSN_BASIC_BLOCK)
|
|
(gdb) p /r $1
|
|
$3 = (rtx_def *) 0x7ffff043e140
|
|
This won't work for coredumps, and probably in other circumstances, but
|
|
it's a quick way of getting lots of debuggability quickly.
|
|
|
|
Callgraph nodes are printed with the name of the function decl, if
|
|
available:
|
|
(gdb) frame 5
|
|
#5 0x00000000006c288a in expand_function (node=<cgraph_node* 0x7ffff0312720 "foo">) at ../../src/gcc/cgraphunit.c:1594
|
|
1594 execute_pass_list (g->get_passes ()->all_passes);
|
|
(gdb) p node
|
|
$1 = <cgraph_node* 0x7ffff0312720 "foo">
|
|
|
|
vec<> pointers are printed as the address followed by the elements in
|
|
braces. Here's a length 2 vec:
|
|
(gdb) p bb->preds
|
|
$18 = 0x7ffff0428b68 = {<edge 0x7ffff044d380 (3 -> 5)>, <edge 0x7ffff044d3b8 (4 -> 5)>}
|
|
|
|
and here's a length 1 vec:
|
|
(gdb) p bb->succs
|
|
$19 = 0x7ffff0428bb8 = {<edge 0x7ffff044d3f0 (5 -> EXIT)>}
|
|
|
|
You cannot yet use array notation [] to access the elements within the
|
|
vector: attempting to do so instead gives you the vec itself (for vec[0]),
|
|
or a (probably) invalid cast to vec<> for the memory after the vec (for
|
|
vec[1] onwards).
|
|
|
|
Instead (for now) you must access m_vecdata:
|
|
(gdb) p bb->preds->m_vecdata[0]
|
|
$20 = <edge 0x7ffff044d380 (3 -> 5)>
|
|
(gdb) p bb->preds->m_vecdata[1]
|
|
$21 = <edge 0x7ffff044d3b8 (4 -> 5)>
|
|
"""
|
|
import re
|
|
|
|
import gdb
|
|
import gdb.printing
|
|
import gdb.types
|
|
|
|
# Convert "enum tree_code" (tree.def and tree.h) to a dict:
|
|
tree_code_dict = gdb.types.make_enum_dict(gdb.lookup_type('enum tree_code'))
|
|
|
|
# ...and look up specific values for use later:
|
|
IDENTIFIER_NODE = tree_code_dict['IDENTIFIER_NODE']
|
|
TYPE_DECL = tree_code_dict['TYPE_DECL']
|
|
|
|
# Similarly for "enum tree_code_class" (tree.h):
|
|
tree_code_class_dict = gdb.types.make_enum_dict(gdb.lookup_type('enum tree_code_class'))
|
|
tcc_type = tree_code_class_dict['tcc_type']
|
|
tcc_declaration = tree_code_class_dict['tcc_declaration']
|
|
|
|
class Tree:
|
|
"""
|
|
Wrapper around a gdb.Value for a tree, with various methods
|
|
corresponding to macros in gcc/tree.h
|
|
"""
|
|
def __init__(self, gdbval):
|
|
self.gdbval = gdbval
|
|
|
|
def is_nonnull(self):
|
|
return long(self.gdbval)
|
|
|
|
def TREE_CODE(self):
|
|
"""
|
|
Get gdb.Value corresponding to TREE_CODE (self)
|
|
as per:
|
|
#define TREE_CODE(NODE) ((enum tree_code) (NODE)->base.code)
|
|
"""
|
|
return self.gdbval['base']['code']
|
|
|
|
def DECL_NAME(self):
|
|
"""
|
|
Get Tree instance corresponding to DECL_NAME (self)
|
|
"""
|
|
return Tree(self.gdbval['decl_minimal']['name'])
|
|
|
|
def TYPE_NAME(self):
|
|
"""
|
|
Get Tree instance corresponding to result of TYPE_NAME (self)
|
|
"""
|
|
return Tree(self.gdbval['type_common']['name'])
|
|
|
|
def IDENTIFIER_POINTER(self):
|
|
"""
|
|
Get str correspoinding to result of IDENTIFIER_NODE (self)
|
|
"""
|
|
return self.gdbval['identifier']['id']['str'].string()
|
|
|
|
class TreePrinter:
|
|
"Prints a tree"
|
|
|
|
def __init__ (self, gdbval):
|
|
self.gdbval = gdbval
|
|
self.node = Tree(gdbval)
|
|
|
|
def to_string (self):
|
|
# like gcc/print-tree.c:print_node_brief
|
|
# #define TREE_CODE(NODE) ((enum tree_code) (NODE)->base.code)
|
|
# tree_code_name[(int) TREE_CODE (node)])
|
|
if long(self.gdbval) == 0:
|
|
return '<tree 0x0>'
|
|
|
|
val_TREE_CODE = self.node.TREE_CODE()
|
|
|
|
# extern const enum tree_code_class tree_code_type[];
|
|
# #define TREE_CODE_CLASS(CODE) tree_code_type[(int) (CODE)]
|
|
|
|
val_tree_code_type = gdb.parse_and_eval('tree_code_type')
|
|
val_tclass = val_tree_code_type[val_TREE_CODE]
|
|
|
|
val_tree_code_name = gdb.parse_and_eval('tree_code_name')
|
|
val_code_name = val_tree_code_name[long(val_TREE_CODE)]
|
|
#print val_code_name.string()
|
|
|
|
result = '<%s 0x%x' % (val_code_name.string(), long(self.gdbval))
|
|
if long(val_tclass) == tcc_declaration:
|
|
tree_DECL_NAME = self.node.DECL_NAME()
|
|
if tree_DECL_NAME.is_nonnull():
|
|
result += ' %s' % tree_DECL_NAME.IDENTIFIER_POINTER()
|
|
else:
|
|
pass # TODO: labels etc
|
|
elif long(val_tclass) == tcc_type:
|
|
tree_TYPE_NAME = Tree(self.gdbval['type_common']['name'])
|
|
if tree_TYPE_NAME.is_nonnull():
|
|
if tree_TYPE_NAME.TREE_CODE() == IDENTIFIER_NODE:
|
|
result += ' %s' % tree_TYPE_NAME.IDENTIFIER_POINTER()
|
|
elif tree_TYPE_NAME.TREE_CODE() == TYPE_DECL:
|
|
if tree_TYPE_NAME.DECL_NAME().is_nonnull():
|
|
result += ' %s' % tree_TYPE_NAME.DECL_NAME().IDENTIFIER_POINTER()
|
|
if self.node.TREE_CODE() == IDENTIFIER_NODE:
|
|
result += ' %s' % self.node.IDENTIFIER_POINTER()
|
|
# etc
|
|
result += '>'
|
|
return result
|
|
|
|
######################################################################
|
|
# Callgraph pretty-printers
|
|
######################################################################
|
|
|
|
class CGraphNodePrinter:
|
|
def __init__(self, gdbval):
|
|
self.gdbval = gdbval
|
|
|
|
def to_string (self):
|
|
result = '<cgraph_node* 0x%x' % long(self.gdbval)
|
|
if long(self.gdbval):
|
|
# symtab_node::name calls lang_hooks.decl_printable_name
|
|
# default implementation (lhd_decl_printable_name) is:
|
|
# return IDENTIFIER_POINTER (DECL_NAME (decl));
|
|
tree_decl = Tree(self.gdbval['decl'])
|
|
result += ' "%s"' % tree_decl.DECL_NAME().IDENTIFIER_POINTER()
|
|
result += '>'
|
|
return result
|
|
|
|
######################################################################
|
|
|
|
class GimplePrinter:
|
|
def __init__(self, gdbval):
|
|
self.gdbval = gdbval
|
|
|
|
def to_string (self):
|
|
if long(self.gdbval) == 0:
|
|
return '<gimple 0x0>'
|
|
val_gimple_code = self.gdbval['code']
|
|
val_gimple_code_name = gdb.parse_and_eval('gimple_code_name')
|
|
val_code_name = val_gimple_code_name[long(val_gimple_code)]
|
|
result = '<%s 0x%x' % (val_code_name.string(),
|
|
long(self.gdbval))
|
|
result += '>'
|
|
return result
|
|
|
|
######################################################################
|
|
# CFG pretty-printers
|
|
######################################################################
|
|
|
|
def bb_index_to_str(index):
|
|
if index == 0:
|
|
return 'ENTRY'
|
|
elif index == 1:
|
|
return 'EXIT'
|
|
else:
|
|
return '%i' % index
|
|
|
|
class BasicBlockPrinter:
|
|
def __init__(self, gdbval):
|
|
self.gdbval = gdbval
|
|
|
|
def to_string (self):
|
|
result = '<basic_block 0x%x' % long(self.gdbval)
|
|
if long(self.gdbval):
|
|
result += ' (%s)' % bb_index_to_str(long(self.gdbval['index']))
|
|
result += '>'
|
|
return result
|
|
|
|
class CfgEdgePrinter:
|
|
def __init__(self, gdbval):
|
|
self.gdbval = gdbval
|
|
|
|
def to_string (self):
|
|
result = '<edge 0x%x' % long(self.gdbval)
|
|
if long(self.gdbval):
|
|
src = bb_index_to_str(long(self.gdbval['src']['index']))
|
|
dest = bb_index_to_str(long(self.gdbval['dest']['index']))
|
|
result += ' (%s -> %s)' % (src, dest)
|
|
result += '>'
|
|
return result
|
|
|
|
######################################################################
|
|
|
|
class Rtx:
|
|
def __init__(self, gdbval):
|
|
self.gdbval = gdbval
|
|
|
|
def GET_CODE(self):
|
|
return self.gdbval['code']
|
|
|
|
def GET_RTX_LENGTH(code):
|
|
val_rtx_length = gdb.parse_and_eval('rtx_length')
|
|
return long(val_rtx_length[code])
|
|
|
|
def GET_RTX_NAME(code):
|
|
val_rtx_name = gdb.parse_and_eval('rtx_name')
|
|
return val_rtx_name[code].string()
|
|
|
|
def GET_RTX_FORMAT(code):
|
|
val_rtx_format = gdb.parse_and_eval('rtx_format')
|
|
return val_rtx_format[code].string()
|
|
|
|
class RtxPrinter:
|
|
def __init__(self, gdbval):
|
|
self.gdbval = gdbval
|
|
self.rtx = Rtx(gdbval)
|
|
|
|
def to_string (self):
|
|
"""
|
|
For now, a cheap kludge: invoke the inferior's print
|
|
function to get a string to use the user, and return an empty
|
|
string for gdb
|
|
"""
|
|
# We use print_inline_rtx to avoid a trailing newline
|
|
gdb.execute('call print_inline_rtx (stderr, (const_rtx) %s, 0)'
|
|
% long(self.gdbval))
|
|
return ''
|
|
|
|
# or by hand; based on gcc/print-rtl.c:print_rtx
|
|
result = ('<rtx_def 0x%x'
|
|
% (long(self.gdbval)))
|
|
code = self.rtx.GET_CODE()
|
|
result += ' (%s' % GET_RTX_NAME(code)
|
|
format_ = GET_RTX_FORMAT(code)
|
|
for i in range(GET_RTX_LENGTH(code)):
|
|
print format_[i]
|
|
result += ')>'
|
|
return result
|
|
|
|
######################################################################
|
|
|
|
class PassPrinter:
|
|
def __init__(self, gdbval):
|
|
self.gdbval = gdbval
|
|
|
|
def to_string (self):
|
|
result = '<opt_pass* 0x%x' % long(self.gdbval)
|
|
if long(self.gdbval):
|
|
result += (' "%s"(%i)'
|
|
% (self.gdbval['name'].string(),
|
|
long(self.gdbval['static_pass_number'])))
|
|
result += '>'
|
|
return result
|
|
|
|
######################################################################
|
|
|
|
class VecPrinter:
|
|
# -ex "up" -ex "p bb->preds"
|
|
def __init__(self, gdbval):
|
|
self.gdbval = gdbval
|
|
|
|
def display_hint (self):
|
|
return 'array'
|
|
|
|
def to_string (self):
|
|
# A trivial implementation; prettyprinting the contents is done
|
|
# by gdb calling the "children" method below.
|
|
return '0x%x' % long(self.gdbval)
|
|
|
|
def children (self):
|
|
if long(self.gdbval) == 0:
|
|
return
|
|
m_vecpfx = self.gdbval['m_vecpfx']
|
|
m_num = m_vecpfx['m_num']
|
|
m_vecdata = self.gdbval['m_vecdata']
|
|
for i in range(m_num):
|
|
yield ('[%d]' % i, m_vecdata[i])
|
|
|
|
######################################################################
|
|
|
|
# TODO:
|
|
# * hashtab
|
|
# * location_t
|
|
|
|
class GdbSubprinter(gdb.printing.SubPrettyPrinter):
|
|
def __init__(self, name, class_):
|
|
super(GdbSubprinter, self).__init__(name)
|
|
self.class_ = class_
|
|
|
|
def handles_type(self, str_type):
|
|
raise NotImplementedError
|
|
|
|
class GdbSubprinterTypeList(GdbSubprinter):
|
|
"""
|
|
A GdbSubprinter that handles a specific set of types
|
|
"""
|
|
def __init__(self, str_types, name, class_):
|
|
super(GdbSubprinterTypeList, self).__init__(name, class_)
|
|
self.str_types = frozenset(str_types)
|
|
|
|
def handles_type(self, str_type):
|
|
return str_type in self.str_types
|
|
|
|
class GdbSubprinterRegex(GdbSubprinter):
|
|
"""
|
|
A GdbSubprinter that handles types that match a regex
|
|
"""
|
|
def __init__(self, regex, name, class_):
|
|
super(GdbSubprinterRegex, self).__init__(name, class_)
|
|
self.regex = re.compile(regex)
|
|
|
|
def handles_type(self, str_type):
|
|
return self.regex.match(str_type)
|
|
|
|
class GdbPrettyPrinters(gdb.printing.PrettyPrinter):
|
|
def __init__(self, name):
|
|
super(GdbPrettyPrinters, self).__init__(name, [])
|
|
|
|
def add_printer_for_types(self, name, class_, types):
|
|
self.subprinters.append(GdbSubprinterTypeList(name, class_, types))
|
|
|
|
def add_printer_for_regex(self, name, class_, regex):
|
|
self.subprinters.append(GdbSubprinterRegex(name, class_, regex))
|
|
|
|
def __call__(self, gdbval):
|
|
type_ = gdbval.type.unqualified()
|
|
str_type = str(type_)
|
|
for printer in self.subprinters:
|
|
if printer.enabled and printer.handles_type(str_type):
|
|
return printer.class_(gdbval)
|
|
|
|
# Couldn't find a pretty printer (or it was disabled):
|
|
return None
|
|
|
|
|
|
def build_pretty_printer():
|
|
pp = GdbPrettyPrinters('gcc')
|
|
pp.add_printer_for_types(['tree'],
|
|
'tree', TreePrinter)
|
|
pp.add_printer_for_types(['cgraph_node *'],
|
|
'cgraph_node', CGraphNodePrinter)
|
|
pp.add_printer_for_types(['gimple', 'gimple_statement_base *'],
|
|
'gimple',
|
|
GimplePrinter)
|
|
pp.add_printer_for_types(['basic_block', 'basic_block_def *'],
|
|
'basic_block',
|
|
BasicBlockPrinter)
|
|
pp.add_printer_for_types(['edge', 'edge_def *'],
|
|
'edge',
|
|
CfgEdgePrinter)
|
|
pp.add_printer_for_types(['rtx_def *'], 'rtx_def', RtxPrinter)
|
|
pp.add_printer_for_types(['opt_pass *'], 'opt_pass', PassPrinter)
|
|
|
|
pp.add_printer_for_regex(r'vec<(\S+), (\S+), (\S+)> \*',
|
|
'vec',
|
|
VecPrinter)
|
|
|
|
return pp
|
|
|
|
gdb.printing.register_pretty_printer(
|
|
gdb.current_objfile(),
|
|
build_pretty_printer())
|
|
|
|
print('Successfully loaded GDB hooks for GCC')
|