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authorBen Cheng <bccheng@google.com>2014-03-25 22:37:19 -0700
committerBen Cheng <bccheng@google.com>2014-03-25 22:37:19 -0700
commit1bc5aee63eb72b341f506ad058502cd0361f0d10 (patch)
treec607e8252f3405424ff15bc2d00aa38dadbb2518 /gcc-4.9/gcc/gdbhooks.py
parent283a0bf58fcf333c58a2a92c3ebbc41fb9eb1fdb (diff)
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Initial checkin of GCC 4.9.0 from trunk (r208799).
Change-Id: I48a3c08bb98542aa215912a75f03c0890e497dba
Diffstat (limited to 'gcc-4.9/gcc/gdbhooks.py')
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+# 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')