--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gcc/gdbhooks.py	Fri Oct 27 22:46:09 2017 +0900
@@ -0,0 +1,790 @@
+# Python hooks for gdb for debugging GCC
+# Copyright (C) 2013-2017 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 os.path
+import re
+import sys
+import tempfile
+
+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']
+
+# Python3 has int() with arbitrary precision (bignum).  Python2 int() is 32-bit
+# on 32-bit hosts but remote targets may have 64-bit pointers there; Python2
+# long() is always 64-bit but Python3 no longer has anything named long.
+def intptr(gdbval):
+    return long(gdbval) if sys.version_info.major == 2 else int(gdbval)
+
+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 intptr(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 intptr(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[intptr(val_TREE_CODE)]
+        #print(val_code_name.string())
+
+        result = '<%s 0x%x' % (val_code_name.string(), intptr(self.gdbval))
+        if intptr(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 intptr(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' % intptr(self.gdbval)
+        if intptr(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
+
+######################################################################
+# Dwarf DIE pretty-printers
+######################################################################
+
+class DWDieRefPrinter:
+    def __init__(self, gdbval):
+        self.gdbval = gdbval
+
+    def to_string (self):
+        if intptr(self.gdbval) == 0:
+            return '<dw_die_ref 0x0>'
+        result = '<dw_die_ref 0x%x' % intptr(self.gdbval)
+        result += ' %s' % self.gdbval['die_tag']
+        if intptr(self.gdbval['die_parent']) != 0:
+            result += ' <parent=0x%x %s>' % (intptr(self.gdbval['die_parent']),
+                                             self.gdbval['die_parent']['die_tag'])
+                                             
+        result += '>'
+        return result
+
+######################################################################
+
+class GimplePrinter:
+    def __init__(self, gdbval):
+        self.gdbval = gdbval
+
+    def to_string (self):
+        if intptr(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[intptr(val_gimple_code)]
+        result = '<%s 0x%x' % (val_code_name.string(),
+                               intptr(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' % intptr(self.gdbval)
+        if intptr(self.gdbval):
+            result += ' (%s)' % bb_index_to_str(intptr(self.gdbval['index']))
+        result += '>'
+        return result
+
+class CfgEdgePrinter:
+    def __init__(self, gdbval):
+        self.gdbval = gdbval
+
+    def to_string (self):
+        result = '<edge 0x%x' % intptr(self.gdbval)
+        if intptr(self.gdbval):
+            src = bb_index_to_str(intptr(self.gdbval['src']['index']))
+            dest = bb_index_to_str(intptr(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 intptr(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)'
+                    % intptr(self.gdbval))
+        return ''
+
+        # or by hand; based on gcc/print-rtl.c:print_rtx
+        result = ('<rtx_def 0x%x'
+                  % (intptr(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' % intptr(self.gdbval)
+        if intptr(self.gdbval):
+            result += (' "%s"(%i)'
+                       % (self.gdbval['name'].string(),
+                          intptr(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' % intptr(self.gdbval)
+
+    def children (self):
+        if intptr(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])
+
+######################################################################
+
+class MachineModePrinter:
+    def __init__(self, gdbval):
+        self.gdbval = gdbval
+
+    def to_string (self):
+        name = str(self.gdbval['m_mode'])
+        return name[2:] if name.startswith('E_') else name
+
+######################################################################
+
+class OptMachineModePrinter:
+    def __init__(self, gdbval):
+        self.gdbval = gdbval
+
+    def to_string (self):
+        name = str(self.gdbval['m_mode'])
+        if name == 'E_VOIDmode':
+            return '<None>'
+        return name[2:] if name.startswith('E_') else name
+
+######################################################################
+
+# 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(['dw_die_ref'],
+                             'dw_die_ref', DWDieRefPrinter)
+    pp.add_printer_for_types(['gimple', 'gimple *',
+
+                              # Keep this in the same order as gimple.def:
+                              'gimple_cond', 'const_gimple_cond',
+                              'gimple_statement_cond *',
+                              'gimple_debug', 'const_gimple_debug',
+                              'gimple_statement_debug *',
+                              'gimple_label', 'const_gimple_label',
+                              'gimple_statement_label *',
+                              'gimple_switch', 'const_gimple_switch',
+                              'gimple_statement_switch *',
+                              'gimple_assign', 'const_gimple_assign',
+                              'gimple_statement_assign *',
+                              'gimple_bind', 'const_gimple_bind',
+                              'gimple_statement_bind *',
+                              'gimple_phi', 'const_gimple_phi',
+                              'gimple_statement_phi *'],
+
+                             '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)
+
+    pp.add_printer_for_regex(r'opt_mode<(\S+)>',
+                             'opt_mode', OptMachineModePrinter)
+    pp.add_printer_for_types(['opt_scalar_int_mode',
+                              'opt_scalar_float_mode',
+                              'opt_scalar_mode'],
+                             'opt_mode', OptMachineModePrinter)
+    pp.add_printer_for_regex(r'pod_mode<(\S+)>',
+                             'pod_mode', MachineModePrinter)
+    pp.add_printer_for_types(['scalar_int_mode_pod',
+                              'scalar_mode_pod'],
+                             'pod_mode', MachineModePrinter)
+    for mode in ('scalar_mode', 'scalar_int_mode', 'scalar_float_mode',
+                 'complex_mode'):
+        pp.add_printer_for_types([mode], mode, MachineModePrinter)
+
+    return pp
+
+gdb.printing.register_pretty_printer(
+    gdb.current_objfile(),
+    build_pretty_printer())
+
+def find_gcc_source_dir():
+    # Use location of global "g" to locate the source tree
+    sym_g = gdb.lookup_global_symbol('g')
+    path = sym_g.symtab.filename # e.g. '../../src/gcc/context.h'
+    srcdir = os.path.split(path)[0] # e.g. '../../src/gcc'
+    return srcdir
+
+class PassNames:
+    """Parse passes.def, gathering a list of pass class names"""
+    def __init__(self):
+        srcdir = find_gcc_source_dir()
+        self.names = []
+        with open(os.path.join(srcdir, 'passes.def')) as f:
+            for line in f:
+                m = re.match('\s*NEXT_PASS \(([^,]+).*\);', line)
+                if m:
+                    self.names.append(m.group(1))
+
+class BreakOnPass(gdb.Command):
+    """
+    A custom command for putting breakpoints on the execute hook of passes.
+    This is largely a workaround for issues with tab-completion in gdb when
+    setting breakpoints on methods on classes within anonymous namespaces.
+
+    Example of use: putting a breakpoint on "final"
+      (gdb) break-on-pass
+    Press <TAB>; it autocompletes to "pass_":
+      (gdb) break-on-pass pass_
+    Press <TAB>:
+      Display all 219 possibilities? (y or n)
+    Press "n"; then type "f":
+      (gdb) break-on-pass pass_f
+    Press <TAB> to autocomplete to pass classnames beginning with "pass_f":
+      pass_fast_rtl_dce              pass_fold_builtins
+      pass_feedback_split_functions  pass_forwprop
+      pass_final                     pass_fre
+      pass_fixup_cfg                 pass_free_cfg
+    Type "in<TAB>" to complete to "pass_final":
+      (gdb) break-on-pass pass_final
+    ...and hit <RETURN>:
+      Breakpoint 6 at 0x8396ba: file ../../src/gcc/final.c, line 4526.
+    ...and we have a breakpoint set; continue execution:
+      (gdb) cont
+      Continuing.
+      Breakpoint 6, (anonymous namespace)::pass_final::execute (this=0x17fb990) at ../../src/gcc/final.c:4526
+      4526	  virtual unsigned int execute (function *) { return rest_of_handle_final (); }
+    """
+    def __init__(self):
+        gdb.Command.__init__(self, 'break-on-pass', gdb.COMMAND_BREAKPOINTS)
+        self.pass_names = None
+
+    def complete(self, text, word):
+        # Lazily load pass names:
+        if not self.pass_names:
+            self.pass_names = PassNames()
+
+        return [name
+                for name in sorted(self.pass_names.names)
+                if name.startswith(text)]
+
+    def invoke(self, arg, from_tty):
+        sym = '(anonymous namespace)::%s::execute' % arg
+        breakpoint = gdb.Breakpoint(sym)
+
+BreakOnPass()
+
+class DumpFn(gdb.Command):
+    """
+    A custom command to dump a gimple/rtl function to file.  By default, it
+    dumps the current function using 0 as dump_flags, but the function and flags
+    can also be specified. If /f <file> are passed as the first two arguments,
+    the dump is written to that file.  Otherwise, a temporary file is created
+    and opened in the text editor specified in the EDITOR environment variable.
+
+    Examples of use:
+      (gdb) dump-fn
+      (gdb) dump-fn /f foo.1.txt
+      (gdb) dump-fn cfun->decl
+      (gdb) dump-fn /f foo.1.txt cfun->decl
+      (gdb) dump-fn cfun->decl 0
+      (gdb) dump-fn cfun->decl dump_flags
+    """
+
+    def __init__(self):
+        gdb.Command.__init__(self, 'dump-fn', gdb.COMMAND_USER)
+
+    def invoke(self, arg, from_tty):
+        # Parse args, check number of args
+        args = gdb.string_to_argv(arg)
+        if len(args) >= 1 and args[0] == "/f":
+            if len(args) == 1:
+                print ("Missing file argument")
+                return
+            filename = args[1]
+            editor_mode = False
+            base_arg = 2
+        else:
+            editor = os.getenv("EDITOR", "")
+            if editor == "":
+                print ("EDITOR environment variable not defined")
+                return
+            editor_mode = True
+            base_arg = 0
+        if len(args) - base_arg > 2:
+            print ("Too many arguments")
+            return
+
+        # Set func
+        if len(args) - base_arg >= 1:
+            funcname = args[base_arg]
+            printfuncname = "function %s" % funcname
+        else:
+            funcname = "cfun ? cfun->decl : current_function_decl"
+            printfuncname = "current function"
+        func = gdb.parse_and_eval(funcname)
+        if func == 0:
+            print ("Could not find %s" % printfuncname)
+            return
+        func = "(tree)%u" % func
+
+        # Set flags
+        if len(args) - base_arg >= 2:
+            flags = gdb.parse_and_eval(args[base_arg + 1])
+        else:
+            flags = 0
+
+        # Get tempory file, if necessary
+        if editor_mode:
+            f = tempfile.NamedTemporaryFile(delete=False, suffix=".txt")
+            filename = f.name
+            f.close()
+
+        # Open file
+        fp = gdb.parse_and_eval("fopen (\"%s\", \"w\")" % filename)
+        if fp == 0:
+            print ("Could not open file: %s" % filename)
+            return
+        fp = "(FILE *)%u" % fp
+
+        # Dump function to file
+        _ = gdb.parse_and_eval("dump_function_to_file (%s, %s, %u)" %
+                               (func, fp, flags))
+
+        # Close file
+        ret = gdb.parse_and_eval("fclose (%s)" % fp)
+        if ret != 0:
+            print ("Could not close file: %s" % filename)
+            return
+
+        # Open file in editor, if necessary
+        if editor_mode:
+            os.system("( %s \"%s\"; rm \"%s\" ) &" %
+                      (editor, filename, filename))
+
+DumpFn()
+
+class DotFn(gdb.Command):
+    """
+    A custom command to show a gimple/rtl function control flow graph.
+    By default, it show the current function, but the function can also be
+    specified.
+
+    Examples of use:
+      (gdb) dot-fn
+      (gdb) dot-fn cfun
+      (gdb) dot-fn cfun 0
+      (gdb) dot-fn cfun dump_flags
+    """
+    def __init__(self):
+        gdb.Command.__init__(self, 'dot-fn', gdb.COMMAND_USER)
+
+    def invoke(self, arg, from_tty):
+        # Parse args, check number of args
+        args = gdb.string_to_argv(arg)
+        if len(args) > 2:
+            print("Too many arguments")
+            return
+
+        # Set func
+        if len(args) >= 1:
+            funcname = args[0]
+            printfuncname = "function %s" % funcname
+        else:
+            funcname = "cfun"
+            printfuncname = "current function"
+        func = gdb.parse_and_eval(funcname)
+        if func == 0:
+            print("Could not find %s" % printfuncname)
+            return
+        func = "(struct function *)%s" % func
+
+        # Set flags
+        if len(args) >= 2:
+            flags = gdb.parse_and_eval(args[1])
+        else:
+            flags = 0
+
+        # Get temp file
+        f = tempfile.NamedTemporaryFile(delete=False)
+        filename = f.name
+
+        # Close and reopen temp file to get C FILE*
+        f.close()
+        fp = gdb.parse_and_eval("fopen (\"%s\", \"w\")" % filename)
+        if fp == 0:
+            print("Cannot open temp file")
+            return
+        fp = "(FILE *)%u" % fp
+
+        # Write graph to temp file
+        _ = gdb.parse_and_eval("start_graph_dump (%s, \"<debug>\")" % fp)
+        _ = gdb.parse_and_eval("print_graph_cfg (%s, %s, %u)"
+                               % (fp, func, flags))
+        _ = gdb.parse_and_eval("end_graph_dump (%s)" % fp)
+
+        # Close temp file
+        ret = gdb.parse_and_eval("fclose (%s)" % fp)
+        if ret != 0:
+            print("Could not close temp file: %s" % filename)
+            return
+
+        # Show graph in temp file
+        os.system("( dot -Tx11 \"%s\"; rm \"%s\" ) &" % (filename, filename))
+
+DotFn()
+
+print('Successfully loaded GDB hooks for GCC')