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Initial version of gdb hooks

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* MAINTAINERS (gdbhooks.py): Add myself as maintainer
    
    gcc/
    	* gdbhooks.py: New.
    	* configure.ac (gdbinit.in): Add import of gcc/gdbhooks.py.
    	* configure: Regenerate.

From-SVN: r202040
This commit is contained in:
David Malcolm 2013-08-28 03:01:20 +00:00 committed by David Malcolm
parent 99236f3ae0
commit 8dce4dbc06
6 changed files with 410 additions and 0 deletions
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4
ChangeLog
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@ -1,3 +1,7 @@
2013-08-27 David Malcolm <dmalcolm@redhat.com>
* MAINTAINERS (gdbhooks.py): Add myself as maintainer.
2013-08-26 Caroline Tice <cmtice@google.com>
* MAINTAINERS: Correct earliers update: Move myself from libvtv

1
MAINTAINERS
View File

@ -257,6 +257,7 @@ testsuite Rainer Orth ro@CeBiTec.Uni-Bielefeld.DE
testsuite Mike Stump mikestump@comcast.net
testsuite Janis Johnson janisjo@codesourcery.com
register allocation Vladimir Makarov vmakarov@redhat.com
gdbhooks.py David Malcolm dmalcolm@redhat.com
Note that individuals who maintain parts of the compiler need approval to
check in changes outside of the parts of the compiler they maintain.

6
gcc/ChangeLog
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@ -1,3 +1,9 @@
2013-08-27 David Malcolm <dmalcolm@redhat.com>
* gdbhooks.py: New.
* configure.ac (gdbinit.in): Add import of gcc/gdbhooks.py.
* configure: Regenerate.
2013-08-27 Martin Jambor <mjambor@suse.cz>
* ipa-prop.h (ipa_pass_through_data): New field type_preserved.

1
gcc/configure vendored
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@ -27397,6 +27397,7 @@ if test "x$subdirs" != x; then
done
fi
echo "source ${srcdir}/gdbinit.in" >> .gdbinit
echo "python import sys; sys.path.append('${srcdir}'); import gdbhooks" >> .gdbinit
gcc_tooldir='$(libsubdir)/$(libsubdir_to_prefix)$(target_noncanonical)'

1
gcc/configure.ac
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@ -5181,6 +5181,7 @@ if test "x$subdirs" != x; then
done
fi
echo "source ${srcdir}/gdbinit.in" >> .gdbinit
echo "python import sys; sys.path.append('${srcdir}'); import gdbhooks" >> .gdbinit
gcc_tooldir='$(libsubdir)/$(libsubdir_to_prefix)$(target_noncanonical)'
AC_SUBST(gcc_tooldir)

397
gcc/gdbhooks.py Normal file
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@ -0,0 +1,397 @@
# Python hooks for gdb for debugging GCC
# Copyright (C) 2013 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">
"""
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));
symbol = self.gdbval['symbol']
tree_decl = Tree(symbol['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['gsbase']['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
######################################################################
# TODO:
# * vec
# * hashtab
# * location_t
class GdbSubprinter(gdb.printing.SubPrettyPrinter):
def __init__(self, name, str_type_, class_):
super(GdbSubprinter, self).__init__(name)
self.str_type_ = str_type_
self.class_ = class_
class GdbPrettyPrinters(gdb.printing.PrettyPrinter):
def __init__(self, name):
super(GdbPrettyPrinters, self).__init__(name, [])
def add_printer(self, name, exp, class_):
self.subprinters.append(GdbSubprinter(name, exp, class_))
def __call__(self, gdbval):
type_ = gdbval.type.unqualified()
str_type_ = str(type_)
for printer in self.subprinters:
if printer.enabled and str_type_ == printer.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('tree', 'tree', TreePrinter)
pp.add_printer('cgraph_node', 'cgraph_node *', CGraphNodePrinter)
pp.add_printer('gimple', 'gimple', GimplePrinter)
pp.add_printer('basic_block', 'basic_block', BasicBlockPrinter)
pp.add_printer('edge', 'edge', CfgEdgePrinter)
pp.add_printer('rtx_def', 'rtx_def *', RtxPrinter)
pp.add_printer('opt_pass', 'opt_pass *', PassPrinter)
return pp
gdb.printing.register_pretty_printer(
gdb.current_objfile(),
build_pretty_printer())
print('Successfully loaded GDB hooks for GCC')