gcc/gdbhooks.py

   1 # Python hooks for gdb for debugging GCC
   2 # Copyright (C) 2013-2019 Free Software Foundation, Inc.
   3
   4 # Contributed by David Malcolm <dmalcolm@redhat.com>
   5
   6 # This file is part of GCC.
   7
   8 # GCC is free software; you can redistribute it and/or modify it under
   9 # the terms of the GNU General Public License as published by the Free
  10 # Software Foundation; either version 3, or (at your option) any later
  11 # version.
  12
  13 # GCC is distributed in the hope that it will be useful, but WITHOUT
  14 # ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  15 # FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  16 # for more details.
  17
  18 # You should have received a copy of the GNU General Public License
  19 # along with GCC; see the file COPYING3.  If not see
  20 # <http://www.gnu.org/licenses/>.
  21
  22 """
  23 Enabling the debugging hooks
  24 ----------------------------
  25 gcc/configure (from configure.ac) generates a .gdbinit within the "gcc"
  26 subdirectory of the build directory, and when run by gdb, this imports
  27 gcc/gdbhooks.py from the source directory, injecting useful Python code
  28 into gdb.
  29
  30 You may see a message from gdb of the form:
  31   "path-to-build/gcc/.gdbinit" auto-loading has been declined by your `auto-load safe-path'
  32 as a protection against untrustworthy python scripts.  See
  33   http://sourceware.org/gdb/onlinedocs/gdb/Auto_002dloading-safe-path.html
  34
  35 The fix is to mark the paths of the build/gcc directory as trustworthy.
  36 An easy way to do so is by adding the following to your ~/.gdbinit script:
  37   add-auto-load-safe-path /absolute/path/to/build/gcc
  38 for the build directories for your various checkouts of gcc.
  39
  40 If it's working, you should see the message:
  41   Successfully loaded GDB hooks for GCC
  42 as gdb starts up.
  43
  44 During development, I've been manually invoking the code in this way, as a
  45 precanned way of printing a variety of different kinds of value:
  46
  47   gdb \
  48     -ex "break expand_gimple_stmt" \
  49     -ex "run" \
  50     -ex "bt" \
  51     --args \
  52       ./cc1 foo.c -O3
  53
  54 Examples of output using the pretty-printers
  55 --------------------------------------------
  56 Pointer values are generally shown in the form:
  57   <type address extra_info>
  58
  59 For example, an opt_pass* might appear as:
  60   (gdb) p pass
  61   $2 = <opt_pass* 0x188b600 "expand"(170)>
  62
  63 The name of the pass is given ("expand"), together with the
  64 static_pass_number.
  65
  66 Note that you can dereference the pointer in the normal way:
  67   (gdb) p *pass
  68   $4 = {type = RTL_PASS, name = 0x120a312 "expand",
  69   [etc, ...snipped...]
  70
  71 and you can suppress pretty-printers using /r (for "raw"):
  72   (gdb) p /r pass
  73   $3 = (opt_pass *) 0x188b600
  74
  75 Basic blocks are shown with their index in parentheses, apart from the
  76 CFG's entry and exit blocks, which are given as "ENTRY" and "EXIT":
  77   (gdb) p bb
  78   $9 = <basic_block 0x7ffff041f1a0 (2)>
  79   (gdb) p cfun->cfg->x_entry_block_ptr
  80   $10 = <basic_block 0x7ffff041f0d0 (ENTRY)>
  81   (gdb) p cfun->cfg->x_exit_block_ptr
  82   $11 = <basic_block 0x7ffff041f138 (EXIT)>
  83
  84 CFG edges are shown with the src and dest blocks given in parentheses:
  85   (gdb) p e
  86   $1 = <edge 0x7ffff043f118 (ENTRY -> 6)>
  87
  88 Tree nodes are printed using Python code that emulates print_node_brief,
  89 running in gdb, rather than in the inferior:
  90   (gdb) p cfun->decl
  91   $1 = <function_decl 0x7ffff0420b00 foo>
  92 For usability, the type is printed first (e.g. "function_decl"), rather
  93 than just "tree".
  94
  95 RTL expressions use a kludge: they are pretty-printed by injecting
  96 calls into print-rtl.c into the inferior:
  97   Value returned is $1 = (note 9 8 10 [bb 3] NOTE_INSN_BASIC_BLOCK)
  98   (gdb) p $1
  99   $2 = (note 9 8 10 [bb 3] NOTE_INSN_BASIC_BLOCK)
 100   (gdb) p /r $1
 101   $3 = (rtx_def *) 0x7ffff043e140
 102 This won't work for coredumps, and probably in other circumstances, but
 103 it's a quick way of getting lots of debuggability quickly.
 104
 105 Callgraph nodes are printed with the name of the function decl, if
 106 available:
 107   (gdb) frame 5
 108   #5  0x00000000006c288a in expand_function (node=<cgraph_node* 0x7ffff0312720 "foo"/12345>) at ../../src/gcc/cgraphunit.c:1594
 109   1594    execute_pass_list (g->get_passes ()->all_passes);
 110   (gdb) p node
 111   $1 = <cgraph_node* 0x7ffff0312720 "foo"/12345>
 112
 113 Similarly for symtab_node and varpool_node classes.
 114
 115 Cgraph edges are printed with the name of caller and callee:
 116     (gdb) p this->callees
 117     $4 = <cgraph_edge* 0x7fffe25aa000 (<cgraph_node * 0x7fffe62b22e0 "_GLOBAL__sub_I__ZN5Pooma5pinfoE"/19660> -> <cgraph_node * 0x7fffe620f730 "__static_initialization_and_destruction_1"/19575>)>
 118
 119 IPA reference follow very similar format:
 120     (gdb) Value returned is $5 = <ipa_ref* 0x7fffefcb80c8 (<symtab_node * 0x7ffff562f000 "__dt_base "/875> -> <symtab_node * 0x7fffe795f000 "_ZTVN6Smarts8RunnableE"/16056>:IPA_REF_ADDR)>
 121
 122 vec<> pointers are printed as the address followed by the elements in
 123 braces.  Here's a length 2 vec:
 124   (gdb) p bb->preds
 125   $18 = 0x7ffff0428b68 = {<edge 0x7ffff044d380 (3 -> 5)>, <edge 0x7ffff044d3b8 (4 -> 5)>}
 126
 127 and here's a length 1 vec:
 128   (gdb) p bb->succs
 129   $19 = 0x7ffff0428bb8 = {<edge 0x7ffff044d3f0 (5 -> EXIT)>}
 130
 131 You cannot yet use array notation [] to access the elements within the
 132 vector: attempting to do so instead gives you the vec itself (for vec[0]),
 133 or a (probably) invalid cast to vec<> for the memory after the vec (for
 134 vec[1] onwards).
 135
 136 Instead (for now) you must access m_vecdata:
 137   (gdb) p bb->preds->m_vecdata[0]
 138   $20 = <edge 0x7ffff044d380 (3 -> 5)>
 139   (gdb) p bb->preds->m_vecdata[1]
 140   $21 = <edge 0x7ffff044d3b8 (4 -> 5)>
 141 """
 142 import os.path
 143 import re
 144 import sys
 145 import tempfile
 146
 147 import gdb
 148 import gdb.printing
 149 import gdb.types
 150
 151 # Convert "enum tree_code" (tree.def and tree.h) to a dict:
 152 tree_code_dict = gdb.types.make_enum_dict(gdb.lookup_type('enum tree_code'))
 153
 154 # ...and look up specific values for use later:
 155 IDENTIFIER_NODE = tree_code_dict['IDENTIFIER_NODE']
 156 TYPE_DECL = tree_code_dict['TYPE_DECL']
 157
 158 # Similarly for "enum tree_code_class" (tree.h):
 159 tree_code_class_dict = gdb.types.make_enum_dict(gdb.lookup_type('enum tree_code_class'))
 160 tcc_type = tree_code_class_dict['tcc_type']
 161 tcc_declaration = tree_code_class_dict['tcc_declaration']
 162
 163 # Python3 has int() with arbitrary precision (bignum).  Python2 int() is 32-bit
 164 # on 32-bit hosts but remote targets may have 64-bit pointers there; Python2
 165 # long() is always 64-bit but Python3 no longer has anything named long.
 166 def intptr(gdbval):
 167     return long(gdbval) if sys.version_info.major == 2 else int(gdbval)
 168
 169 class Tree:
 170     """
 171     Wrapper around a gdb.Value for a tree, with various methods
 172     corresponding to macros in gcc/tree.h
 173     """
 174     def __init__(self, gdbval):
 175         self.gdbval = gdbval
 176
 177     def is_nonnull(self):
 178         return intptr(self.gdbval)
 179
 180     def TREE_CODE(self):
 181         """
 182         Get gdb.Value corresponding to TREE_CODE (self)
 183         as per:
 184           #define TREE_CODE(NODE) ((enum tree_code) (NODE)->base.code)
 185         """
 186         return self.gdbval['base']['code']
 187
 188     def DECL_NAME(self):
 189         """
 190         Get Tree instance corresponding to DECL_NAME (self)
 191         """
 192         return Tree(self.gdbval['decl_minimal']['name'])
 193
 194     def TYPE_NAME(self):
 195         """
 196         Get Tree instance corresponding to result of TYPE_NAME (self)
 197         """
 198         return Tree(self.gdbval['type_common']['name'])
 199
 200     def IDENTIFIER_POINTER(self):
 201         """
 202         Get str correspoinding to result of IDENTIFIER_NODE (self)
 203         """
 204         return self.gdbval['identifier']['id']['str'].string()
 205
 206 class TreePrinter:
 207     "Prints a tree"
 208
 209     def __init__ (self, gdbval):
 210         self.gdbval = gdbval
 211         self.node = Tree(gdbval)
 212
 213     def to_string (self):
 214         # like gcc/print-tree.c:print_node_brief
 215         # #define TREE_CODE(NODE) ((enum tree_code) (NODE)->base.code)
 216         # tree_code_name[(int) TREE_CODE (node)])
 217         if intptr(self.gdbval) == 0:
 218             return '<tree 0x0>'
 219
 220         val_TREE_CODE = self.node.TREE_CODE()
 221
 222         # extern const enum tree_code_class tree_code_type[];
 223         # #define TREE_CODE_CLASS(CODE) tree_code_type[(int) (CODE)]
 224
 225         val_tree_code_type = gdb.parse_and_eval('tree_code_type')
 226         val_tclass = val_tree_code_type[val_TREE_CODE]
 227
 228         val_tree_code_name = gdb.parse_and_eval('tree_code_name')
 229         val_code_name = val_tree_code_name[intptr(val_TREE_CODE)]
 230         #print(val_code_name.string())
 231
 232         try:
 233             result = '<%s 0x%x' % (val_code_name.string(), intptr(self.gdbval))
 234         except:
 235             return '<tree 0x%x>' % intptr(self.gdbval)
 236         if intptr(val_tclass) == tcc_declaration:
 237             tree_DECL_NAME = self.node.DECL_NAME()
 238             if tree_DECL_NAME.is_nonnull():
 239                  result += ' %s' % tree_DECL_NAME.IDENTIFIER_POINTER()
 240             else:
 241                 pass # TODO: labels etc
 242         elif intptr(val_tclass) == tcc_type:
 243             tree_TYPE_NAME = Tree(self.gdbval['type_common']['name'])
 244             if tree_TYPE_NAME.is_nonnull():
 245                 if tree_TYPE_NAME.TREE_CODE() == IDENTIFIER_NODE:
 246                     result += ' %s' % tree_TYPE_NAME.IDENTIFIER_POINTER()
 247                 elif tree_TYPE_NAME.TREE_CODE() == TYPE_DECL:
 248                     if tree_TYPE_NAME.DECL_NAME().is_nonnull():
 249                         result += ' %s' % tree_TYPE_NAME.DECL_NAME().IDENTIFIER_POINTER()
 250         if self.node.TREE_CODE() == IDENTIFIER_NODE:
 251             result += ' %s' % self.node.IDENTIFIER_POINTER()
 252         # etc
 253         result += '>'
 254         return result
 255
 256 ######################################################################
 257 # Callgraph pretty-printers
 258 ######################################################################
 259
 260 class SymtabNodePrinter:
 261     def __init__(self, gdbval):
 262         self.gdbval = gdbval
 263
 264     def to_string (self):
 265         t = str(self.gdbval.type)
 266         result = '<%s 0x%x' % (t, intptr(self.gdbval))
 267         if intptr(self.gdbval):
 268             # symtab_node::name calls lang_hooks.decl_printable_name
 269             # default implementation (lhd_decl_printable_name) is:
 270             #    return IDENTIFIER_POINTER (DECL_NAME (decl));
 271             tree_decl = Tree(self.gdbval['decl'])
 272             result += ' "%s"/%d' % (tree_decl.DECL_NAME().IDENTIFIER_POINTER(), self.gdbval['order'])
 273         result += '>'
 274         return result
 275
 276 class CgraphEdgePrinter:
 277     def __init__(self, gdbval):
 278         self.gdbval = gdbval
 279
 280     def to_string (self):
 281         result = '<cgraph_edge* 0x%x' % intptr(self.gdbval)
 282         if intptr(self.gdbval):
 283             src = SymtabNodePrinter(self.gdbval['caller']).to_string()
 284             dest = SymtabNodePrinter(self.gdbval['callee']).to_string()
 285             result += ' (%s -> %s)' % (src, dest)
 286         result += '>'
 287         return result
 288
 289 class IpaReferencePrinter:
 290     def __init__(self, gdbval):
 291         self.gdbval = gdbval
 292
 293     def to_string (self):
 294         result = '<ipa_ref* 0x%x' % intptr(self.gdbval)
 295         if intptr(self.gdbval):
 296             src = SymtabNodePrinter(self.gdbval['referring']).to_string()
 297             dest = SymtabNodePrinter(self.gdbval['referred']).to_string()
 298             result += ' (%s -> %s:%s)' % (src, dest, str(self.gdbval['use']))
 299         result += '>'
 300         return result
 301
 302 ######################################################################
 303 # Dwarf DIE pretty-printers
 304 ######################################################################
 305
 306 class DWDieRefPrinter:
 307     def __init__(self, gdbval):
 308         self.gdbval = gdbval
 309
 310     def to_string (self):
 311         if intptr(self.gdbval) == 0:
 312             return '<dw_die_ref 0x0>'
 313         result = '<dw_die_ref 0x%x' % intptr(self.gdbval)
 314         result += ' %s' % self.gdbval['die_tag']
 315         if intptr(self.gdbval['die_parent']) != 0:
 316             result += ' <parent=0x%x %s>' % (intptr(self.gdbval['die_parent']),
 317                                              self.gdbval['die_parent']['die_tag'])
 318
 319         result += '>'
 320         return result
 321
 322 ######################################################################
 323
 324 class GimplePrinter:
 325     def __init__(self, gdbval):
 326         self.gdbval = gdbval
 327
 328     def to_string (self):
 329         if intptr(self.gdbval) == 0:
 330             return '<gimple 0x0>'
 331         val_gimple_code = self.gdbval['code']
 332         val_gimple_code_name = gdb.parse_and_eval('gimple_code_name')
 333         val_code_name = val_gimple_code_name[intptr(val_gimple_code)]
 334         result = '<%s 0x%x' % (val_code_name.string(),
 335                                intptr(self.gdbval))
 336         result += '>'
 337         return result
 338
 339 ######################################################################
 340 # CFG pretty-printers
 341 ######################################################################
 342
 343 def bb_index_to_str(index):
 344     if index == 0:
 345         return 'ENTRY'
 346     elif index == 1:
 347         return 'EXIT'
 348     else:
 349         return '%i' % index
 350
 351 class BasicBlockPrinter:
 352     def __init__(self, gdbval):
 353         self.gdbval = gdbval
 354
 355     def to_string (self):
 356         result = '<basic_block 0x%x' % intptr(self.gdbval)
 357         if intptr(self.gdbval):
 358             result += ' (%s)' % bb_index_to_str(intptr(self.gdbval['index']))
 359         result += '>'
 360         return result
 361
 362 class CfgEdgePrinter:
 363     def __init__(self, gdbval):
 364         self.gdbval = gdbval
 365
 366     def to_string (self):
 367         result = '<edge 0x%x' % intptr(self.gdbval)
 368         if intptr(self.gdbval):
 369             src = bb_index_to_str(intptr(self.gdbval['src']['index']))
 370             dest = bb_index_to_str(intptr(self.gdbval['dest']['index']))
 371             result += ' (%s -> %s)' % (src, dest)
 372         result += '>'
 373         return result
 374
 375 ######################################################################
 376
 377 class Rtx:
 378     def __init__(self, gdbval):
 379         self.gdbval = gdbval
 380
 381     def GET_CODE(self):
 382         return self.gdbval['code']
 383
 384 def GET_RTX_LENGTH(code):
 385     val_rtx_length = gdb.parse_and_eval('rtx_length')
 386     return intptr(val_rtx_length[code])
 387
 388 def GET_RTX_NAME(code):
 389     val_rtx_name = gdb.parse_and_eval('rtx_name')
 390     return val_rtx_name[code].string()
 391
 392 def GET_RTX_FORMAT(code):
 393     val_rtx_format = gdb.parse_and_eval('rtx_format')
 394     return val_rtx_format[code].string()
 395
 396 class RtxPrinter:
 397     def __init__(self, gdbval):
 398         self.gdbval = gdbval
 399         self.rtx = Rtx(gdbval)
 400
 401     def to_string (self):
 402         """
 403         For now, a cheap kludge: invoke the inferior's print
 404         function to get a string to use the user, and return an empty
 405         string for gdb
 406         """
 407         # We use print_inline_rtx to avoid a trailing newline
 408         gdb.execute('call print_inline_rtx (stderr, (const_rtx) %s, 0)'
 409                     % intptr(self.gdbval))
 410         return ''
 411
 412         # or by hand; based on gcc/print-rtl.c:print_rtx
 413         result = ('<rtx_def 0x%x'
 414                   % (intptr(self.gdbval)))
 415         code = self.rtx.GET_CODE()
 416         result += ' (%s' % GET_RTX_NAME(code)
 417         format_ = GET_RTX_FORMAT(code)
 418         for i in range(GET_RTX_LENGTH(code)):
 419             print(format_[i])
 420         result += ')>'
 421         return result
 422
 423 ######################################################################
 424
 425 class PassPrinter:
 426     def __init__(self, gdbval):
 427         self.gdbval = gdbval
 428
 429     def to_string (self):
 430         result = '<opt_pass* 0x%x' % intptr(self.gdbval)
 431         if intptr(self.gdbval):
 432             result += (' "%s"(%i)'
 433                        % (self.gdbval['name'].string(),
 434                           intptr(self.gdbval['static_pass_number'])))
 435         result += '>'
 436         return result
 437
 438 ######################################################################
 439
 440 class VecPrinter:
 441     #    -ex "up" -ex "p bb->preds"
 442     def __init__(self, gdbval):
 443         self.gdbval = gdbval
 444
 445     def display_hint (self):
 446         return 'array'
 447
 448     def to_string (self):
 449         # A trivial implementation; prettyprinting the contents is done
 450         # by gdb calling the "children" method below.
 451         return '0x%x' % intptr(self.gdbval)
 452
 453     def children (self):
 454         if intptr(self.gdbval) == 0:
 455             return
 456         m_vecpfx = self.gdbval['m_vecpfx']
 457         m_num = m_vecpfx['m_num']
 458         m_vecdata = self.gdbval['m_vecdata']
 459         for i in range(m_num):
 460             yield ('[%d]' % i, m_vecdata[i])
 461
 462 ######################################################################
 463
 464 class MachineModePrinter:
 465     def __init__(self, gdbval):
 466         self.gdbval = gdbval
 467
 468     def to_string (self):
 469         name = str(self.gdbval['m_mode'])
 470         return name[2:] if name.startswith('E_') else name
 471
 472 ######################################################################
 473
 474 class OptMachineModePrinter:
 475     def __init__(self, gdbval):
 476         self.gdbval = gdbval
 477
 478     def to_string (self):
 479         name = str(self.gdbval['m_mode'])
 480         if name == 'E_VOIDmode':
 481             return '<None>'
 482         return name[2:] if name.startswith('E_') else name
 483
 484 ######################################################################
 485
 486 # TODO:
 487 #   * hashtab
 488 #   * location_t
 489
 490 class GdbSubprinter(gdb.printing.SubPrettyPrinter):
 491     def __init__(self, name, class_):
 492         super(GdbSubprinter, self).__init__(name)
 493         self.class_ = class_
 494
 495     def handles_type(self, str_type):
 496         raise NotImplementedError
 497
 498 class GdbSubprinterTypeList(GdbSubprinter):
 499     """
 500     A GdbSubprinter that handles a specific set of types
 501     """
 502     def __init__(self, str_types, name, class_):
 503         super(GdbSubprinterTypeList, self).__init__(name, class_)
 504         self.str_types = frozenset(str_types)
 505
 506     def handles_type(self, str_type):
 507         return str_type in self.str_types
 508
 509 class GdbSubprinterRegex(GdbSubprinter):
 510     """
 511     A GdbSubprinter that handles types that match a regex
 512     """
 513     def __init__(self, regex, name, class_):
 514         super(GdbSubprinterRegex, self).__init__(name, class_)
 515         self.regex = re.compile(regex)
 516
 517     def handles_type(self, str_type):
 518         return self.regex.match(str_type)
 519
 520 class GdbPrettyPrinters(gdb.printing.PrettyPrinter):
 521     def __init__(self, name):
 522         super(GdbPrettyPrinters, self).__init__(name, [])
 523
 524     def add_printer_for_types(self, name, class_, types):
 525         self.subprinters.append(GdbSubprinterTypeList(name, class_, types))
 526
 527     def add_printer_for_regex(self, name, class_, regex):
 528         self.subprinters.append(GdbSubprinterRegex(name, class_, regex))
 529
 530     def __call__(self, gdbval):
 531         type_ = gdbval.type.unqualified()
 532         str_type = str(type_)
 533         for printer in self.subprinters:
 534             if printer.enabled and printer.handles_type(str_type):
 535                 return printer.class_(gdbval)
 536
 537         # Couldn't find a pretty printer (or it was disabled):
 538         return None
 539
 540
 541 def build_pretty_printer():
 542     pp = GdbPrettyPrinters('gcc')
 543     pp.add_printer_for_types(['tree', 'const_tree'],
 544                              'tree', TreePrinter)
 545     pp.add_printer_for_types(['cgraph_node *', 'varpool_node *', 'symtab_node *'],
 546                              'symtab_node', SymtabNodePrinter)
 547     pp.add_printer_for_types(['cgraph_edge *'],
 548                              'cgraph_edge', CgraphEdgePrinter)
 549     pp.add_printer_for_types(['ipa_ref *'],
 550                              'ipa_ref', IpaReferencePrinter)
 551     pp.add_printer_for_types(['dw_die_ref'],
 552                              'dw_die_ref', DWDieRefPrinter)
 553     pp.add_printer_for_types(['gimple', 'gimple *',
 554
 555                               # Keep this in the same order as gimple.def:
 556                               'gimple_cond', 'const_gimple_cond',
 557                               'gimple_statement_cond *',
 558                               'gimple_debug', 'const_gimple_debug',
 559                               'gimple_statement_debug *',
 560                               'gimple_label', 'const_gimple_label',
 561                               'gimple_statement_label *',
 562                               'gimple_switch', 'const_gimple_switch',
 563                               'gimple_statement_switch *',
 564                               'gimple_assign', 'const_gimple_assign',
 565                               'gimple_statement_assign *',
 566                               'gimple_bind', 'const_gimple_bind',
 567                               'gimple_statement_bind *',
 568                               'gimple_phi', 'const_gimple_phi',
 569                               'gimple_statement_phi *'],
 570
 571                              'gimple',
 572                              GimplePrinter)
 573     pp.add_printer_for_types(['basic_block', 'basic_block_def *'],
 574                              'basic_block',
 575                              BasicBlockPrinter)
 576     pp.add_printer_for_types(['edge', 'edge_def *'],
 577                              'edge',
 578                              CfgEdgePrinter)
 579     pp.add_printer_for_types(['rtx_def *'], 'rtx_def', RtxPrinter)
 580     pp.add_printer_for_types(['opt_pass *'], 'opt_pass', PassPrinter)
 581
 582     pp.add_printer_for_regex(r'vec<(\S+), (\S+), (\S+)> \*',
 583                              'vec',
 584                              VecPrinter)
 585
 586     pp.add_printer_for_regex(r'opt_mode<(\S+)>',
 587                              'opt_mode', OptMachineModePrinter)
 588     pp.add_printer_for_types(['opt_scalar_int_mode',
 589                               'opt_scalar_float_mode',
 590                               'opt_scalar_mode'],
 591                              'opt_mode', OptMachineModePrinter)
 592     pp.add_printer_for_regex(r'pod_mode<(\S+)>',
 593                              'pod_mode', MachineModePrinter)
 594     pp.add_printer_for_types(['scalar_int_mode_pod',
 595                               'scalar_mode_pod'],
 596                              'pod_mode', MachineModePrinter)
 597     for mode in ('scalar_mode', 'scalar_int_mode', 'scalar_float_mode',
 598                  'complex_mode'):
 599         pp.add_printer_for_types([mode], mode, MachineModePrinter)
 600
 601     return pp
 602
 603 gdb.printing.register_pretty_printer(
 604     gdb.current_objfile(),
 605     build_pretty_printer())
 606
 607 def find_gcc_source_dir():
 608     # Use location of global "g" to locate the source tree
 609     sym_g = gdb.lookup_global_symbol('g')
 610     path = sym_g.symtab.filename # e.g. '../../src/gcc/context.h'
 611     srcdir = os.path.split(path)[0] # e.g. '../../src/gcc'
 612     return srcdir
 613
 614 class PassNames:
 615     """Parse passes.def, gathering a list of pass class names"""
 616     def __init__(self):
 617         srcdir = find_gcc_source_dir()
 618         self.names = []
 619         with open(os.path.join(srcdir, 'passes.def')) as f:
 620             for line in f:
 621                 m = re.match('\s*NEXT_PASS \(([^,]+).*\);', line)
 622                 if m:
 623                     self.names.append(m.group(1))
 624
 625 class BreakOnPass(gdb.Command):
 626     """
 627     A custom command for putting breakpoints on the execute hook of passes.
 628     This is largely a workaround for issues with tab-completion in gdb when
 629     setting breakpoints on methods on classes within anonymous namespaces.
 630
 631     Example of use: putting a breakpoint on "final"
 632       (gdb) break-on-pass
 633     Press <TAB>; it autocompletes to "pass_":
 634       (gdb) break-on-pass pass_
 635     Press <TAB>:
 636       Display all 219 possibilities? (y or n)
 637     Press "n"; then type "f":
 638       (gdb) break-on-pass pass_f
 639     Press <TAB> to autocomplete to pass classnames beginning with "pass_f":
 640       pass_fast_rtl_dce              pass_fold_builtins
 641       pass_feedback_split_functions  pass_forwprop
 642       pass_final                     pass_fre
 643       pass_fixup_cfg                 pass_free_cfg
 644     Type "in<TAB>" to complete to "pass_final":
 645       (gdb) break-on-pass pass_final
 646     ...and hit <RETURN>:
 647       Breakpoint 6 at 0x8396ba: file ../../src/gcc/final.c, line 4526.
 648     ...and we have a breakpoint set; continue execution:
 649       (gdb) cont
 650       Continuing.
 651       Breakpoint 6, (anonymous namespace)::pass_final::execute (this=0x17fb990) at ../../src/gcc/final.c:4526
 652       4526        virtual unsigned int execute (function *) { return rest_of_handle_final (); }
 653     """
 654     def __init__(self):
 655         gdb.Command.__init__(self, 'break-on-pass', gdb.COMMAND_BREAKPOINTS)
 656         self.pass_names = None
 657
 658     def complete(self, text, word):
 659         # Lazily load pass names:
 660         if not self.pass_names:
 661             self.pass_names = PassNames()
 662
 663         return [name
 664                 for name in sorted(self.pass_names.names)
 665                 if name.startswith(text)]
 666
 667     def invoke(self, arg, from_tty):
 668         sym = '(anonymous namespace)::%s::execute' % arg
 669         breakpoint = gdb.Breakpoint(sym)
 670
 671 BreakOnPass()
 672
 673 class DumpFn(gdb.Command):
 674     """
 675     A custom command to dump a gimple/rtl function to file.  By default, it
 676     dumps the current function using 0 as dump_flags, but the function and flags
 677     can also be specified. If /f <file> are passed as the first two arguments,
 678     the dump is written to that file.  Otherwise, a temporary file is created
 679     and opened in the text editor specified in the EDITOR environment variable.
 680
 681     Examples of use:
 682       (gdb) dump-fn
 683       (gdb) dump-fn /f foo.1.txt
 684       (gdb) dump-fn cfun->decl
 685       (gdb) dump-fn /f foo.1.txt cfun->decl
 686       (gdb) dump-fn cfun->decl 0
 687       (gdb) dump-fn cfun->decl dump_flags
 688     """
 689
 690     def __init__(self):
 691         gdb.Command.__init__(self, 'dump-fn', gdb.COMMAND_USER)
 692
 693     def invoke(self, arg, from_tty):
 694         # Parse args, check number of args
 695         args = gdb.string_to_argv(arg)
 696         if len(args) >= 1 and args[0] == "/f":
 697             if len(args) == 1:
 698                 print ("Missing file argument")
 699                 return
 700             filename = args[1]
 701             editor_mode = False
 702             base_arg = 2
 703         else:
 704             editor = os.getenv("EDITOR", "")
 705             if editor == "":
 706                 print ("EDITOR environment variable not defined")
 707                 return
 708             editor_mode = True
 709             base_arg = 0
 710         if len(args) - base_arg > 2:
 711             print ("Too many arguments")
 712             return
 713
 714         # Set func
 715         if len(args) - base_arg >= 1:
 716             funcname = args[base_arg]
 717             printfuncname = "function %s" % funcname
 718         else:
 719             funcname = "cfun ? cfun->decl : current_function_decl"
 720             printfuncname = "current function"
 721         func = gdb.parse_and_eval(funcname)
 722         if func == 0:
 723             print ("Could not find %s" % printfuncname)
 724             return
 725         func = "(tree)%u" % func
 726
 727         # Set flags
 728         if len(args) - base_arg >= 2:
 729             flags = gdb.parse_and_eval(args[base_arg + 1])
 730         else:
 731             flags = 0
 732
 733         # Get tempory file, if necessary
 734         if editor_mode:
 735             f = tempfile.NamedTemporaryFile(delete=False, suffix=".txt")
 736             filename = f.name
 737             f.close()
 738
 739         # Open file
 740         fp = gdb.parse_and_eval("fopen (\"%s\", \"w\")" % filename)
 741         if fp == 0:
 742             print ("Could not open file: %s" % filename)
 743             return
 744         fp = "(FILE *)%u" % fp
 745
 746         # Dump function to file
 747         _ = gdb.parse_and_eval("dump_function_to_file (%s, %s, %u)" %
 748                                (func, fp, flags))
 749
 750         # Close file
 751         ret = gdb.parse_and_eval("fclose (%s)" % fp)
 752         if ret != 0:
 753             print ("Could not close file: %s" % filename)
 754             return
 755
 756         # Open file in editor, if necessary
 757         if editor_mode:
 758             os.system("( %s \"%s\"; rm \"%s\" ) &" %
 759                       (editor, filename, filename))
 760
 761 DumpFn()
 762
 763 class DotFn(gdb.Command):
 764     """
 765     A custom command to show a gimple/rtl function control flow graph.
 766     By default, it show the current function, but the function can also be
 767     specified.
 768
 769     Examples of use:
 770       (gdb) dot-fn
 771       (gdb) dot-fn cfun
 772       (gdb) dot-fn cfun 0
 773       (gdb) dot-fn cfun dump_flags
 774     """
 775     def __init__(self):
 776         gdb.Command.__init__(self, 'dot-fn', gdb.COMMAND_USER)
 777
 778     def invoke(self, arg, from_tty):
 779         # Parse args, check number of args
 780         args = gdb.string_to_argv(arg)
 781         if len(args) > 2:
 782             print("Too many arguments")
 783             return
 784
 785         # Set func
 786         if len(args) >= 1:
 787             funcname = args[0]
 788             printfuncname = "function %s" % funcname
 789         else:
 790             funcname = "cfun"
 791             printfuncname = "current function"
 792         func = gdb.parse_and_eval(funcname)
 793         if func == 0:
 794             print("Could not find %s" % printfuncname)
 795             return
 796         func = "(struct function *)%s" % func
 797
 798         # Set flags
 799         if len(args) >= 2:
 800             flags = gdb.parse_and_eval(args[1])
 801         else:
 802             flags = 0
 803
 804         # Get temp file
 805         f = tempfile.NamedTemporaryFile(delete=False)
 806         filename = f.name
 807
 808         # Close and reopen temp file to get C FILE*
 809         f.close()
 810         fp = gdb.parse_and_eval("fopen (\"%s\", \"w\")" % filename)
 811         if fp == 0:
 812             print("Cannot open temp file")
 813             return
 814         fp = "(FILE *)%u" % fp
 815
 816         # Write graph to temp file
 817         _ = gdb.parse_and_eval("start_graph_dump (%s, \"<debug>\")" % fp)
 818         _ = gdb.parse_and_eval("print_graph_cfg (%s, %s, %u)"
 819                                % (fp, func, flags))
 820         _ = gdb.parse_and_eval("end_graph_dump (%s)" % fp)
 821
 822         # Close temp file
 823         ret = gdb.parse_and_eval("fclose (%s)" % fp)
 824         if ret != 0:
 825             print("Could not close temp file: %s" % filename)
 826             return
 827
 828         # Show graph in temp file
 829         os.system("( dot -Tx11 \"%s\"; rm \"%s\" ) &" % (filename, filename))
 830
 831 DotFn()
 832
 833 print('Successfully loaded GDB hooks for GCC')