gcc/gdbhooks.py

   1 # Python hooks for gdb for debugging GCC
   2 # Copyright (C) 2013-2024 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 the payload directly:
 137   (gdb) p ((edge_def**)(bb->preds+1))[0]
 138   $20 = <edge 0x7ffff044d380 (3 -> 5)>
 139   (gdb) p ((edge_def**)(bb->preds+1))[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 SSA_NAME = tree_code_dict['SSA_NAME']
 158
 159 # Similarly for "enum tree_code_class" (tree.h):
 160 tree_code_class_dict = gdb.types.make_enum_dict(gdb.lookup_type('enum tree_code_class'))
 161 tcc_type = tree_code_class_dict['tcc_type']
 162 tcc_declaration = tree_code_class_dict['tcc_declaration']
 163
 164 # Python3 has int() with arbitrary precision (bignum).  Python2 int() is 32-bit
 165 # on 32-bit hosts but remote targets may have 64-bit pointers there; Python2
 166 # long() is always 64-bit but Python3 no longer has anything named long.
 167 def intptr(gdbval):
 168     return long(gdbval) if sys.version_info.major == 2 else int(gdbval)
 169
 170 class Tree:
 171     """
 172     Wrapper around a gdb.Value for a tree, with various methods
 173     corresponding to macros in gcc/tree.h
 174     """
 175     def __init__(self, gdbval):
 176         self.gdbval = gdbval
 177
 178     def is_nonnull(self):
 179         return intptr(self.gdbval)
 180
 181     def TREE_CODE(self):
 182         """
 183         Get gdb.Value corresponding to TREE_CODE (self)
 184         as per:
 185           #define TREE_CODE(NODE) ((enum tree_code) (NODE)->base.code)
 186         """
 187         return self.gdbval['base']['code']
 188
 189     def DECL_NAME(self):
 190         """
 191         Get Tree instance corresponding to DECL_NAME (self)
 192         """
 193         return Tree(self.gdbval['decl_minimal']['name'])
 194
 195     def TYPE_NAME(self):
 196         """
 197         Get Tree instance corresponding to result of TYPE_NAME (self)
 198         """
 199         return Tree(self.gdbval['type_common']['name'])
 200
 201     def IDENTIFIER_POINTER(self):
 202         """
 203         Get str correspoinding to result of IDENTIFIER_NODE (self)
 204         """
 205         return self.gdbval['identifier']['id']['str'].string()
 206
 207 class TreePrinter:
 208     "Prints a tree"
 209
 210     def __init__ (self, gdbval):
 211         self.gdbval = gdbval
 212         self.node = Tree(gdbval)
 213
 214     def to_string (self):
 215         # like gcc/print-tree.c:print_node_brief
 216         # #define TREE_CODE(NODE) ((enum tree_code) (NODE)->base.code)
 217         # tree_code_name[(int) TREE_CODE (node)])
 218         if intptr(self.gdbval) == 0:
 219             return '<tree 0x0>'
 220
 221         val_TREE_CODE = self.node.TREE_CODE()
 222
 223         # constexpr inline enum tree_code_class tree_code_type[] = { ... };
 224         # #define TREE_CODE_CLASS(CODE) tree_code_type[(int) (CODE)]
 225         # or
 226         # template <int N>
 227         # struct tree_code_type_tmpl {
 228         # static constexpr enum tree_code_class tree_code_type[] = { ... };
 229         # }; };
 230         # #define TREE_CODE_CLASS(CODE) \
 231         # tree_code_type_tmpl <0>::tree_code_type[(int) (CODE)]
 232
 233         if val_TREE_CODE == 0xa5a5:
 234             return '<ggc_freed 0x%x>' % intptr(self.gdbval)
 235
 236         try:
 237             val_tree_code_type = gdb.parse_and_eval('tree_code_type')
 238         except:
 239             val_tree_code_type = gdb.parse_and_eval('tree_code_type_tmpl<0>::tree_code_type')
 240         val_tclass = val_tree_code_type[val_TREE_CODE]
 241
 242         val_tree_code_name = gdb.parse_and_eval('tree_code_name')
 243         val_code_name = val_tree_code_name[intptr(val_TREE_CODE)]
 244         #print(val_code_name.string())
 245
 246         try:
 247             result = '<%s 0x%x' % (val_code_name.string(), intptr(self.gdbval))
 248         except:
 249             return '<tree 0x%x>' % intptr(self.gdbval)
 250         if intptr(val_tclass) == tcc_declaration:
 251             tree_DECL_NAME = self.node.DECL_NAME()
 252             if tree_DECL_NAME.is_nonnull():
 253                  result += ' %s' % tree_DECL_NAME.IDENTIFIER_POINTER()
 254             else:
 255                 pass # TODO: labels etc
 256         elif intptr(val_tclass) == tcc_type:
 257             tree_TYPE_NAME = Tree(self.gdbval['type_common']['name'])
 258             if tree_TYPE_NAME.is_nonnull():
 259                 if tree_TYPE_NAME.TREE_CODE() == IDENTIFIER_NODE:
 260                     result += ' %s' % tree_TYPE_NAME.IDENTIFIER_POINTER()
 261                 elif tree_TYPE_NAME.TREE_CODE() == TYPE_DECL:
 262                     if tree_TYPE_NAME.DECL_NAME().is_nonnull():
 263                         result += ' %s' % tree_TYPE_NAME.DECL_NAME().IDENTIFIER_POINTER()
 264         if self.node.TREE_CODE() == IDENTIFIER_NODE:
 265             result += ' %s' % self.node.IDENTIFIER_POINTER()
 266         elif self.node.TREE_CODE() == SSA_NAME:
 267             result += ' %u' % self.gdbval['base']['u']['version']
 268         # etc
 269         result += '>'
 270         return result
 271
 272 ######################################################################
 273 # Callgraph pretty-printers
 274 ######################################################################
 275
 276 class SymtabNodePrinter:
 277     def __init__(self, gdbval):
 278         self.gdbval = gdbval
 279
 280     def to_string (self):
 281         t = str(self.gdbval.type)
 282         result = '<%s 0x%x' % (t, intptr(self.gdbval))
 283         if intptr(self.gdbval):
 284             # symtab_node::name calls lang_hooks.decl_printable_name
 285             # default implementation (lhd_decl_printable_name) is:
 286             #    return IDENTIFIER_POINTER (DECL_NAME (decl));
 287             tree_decl = Tree(self.gdbval['decl'])
 288             result += ' "%s"/%d' % (tree_decl.DECL_NAME().IDENTIFIER_POINTER(), self.gdbval['order'])
 289         result += '>'
 290         return result
 291
 292 class CgraphEdgePrinter:
 293     def __init__(self, gdbval):
 294         self.gdbval = gdbval
 295
 296     def to_string (self):
 297         result = '<cgraph_edge* 0x%x' % intptr(self.gdbval)
 298         if intptr(self.gdbval):
 299             src = SymtabNodePrinter(self.gdbval['caller']).to_string()
 300             dest = SymtabNodePrinter(self.gdbval['callee']).to_string()
 301             result += ' (%s -> %s)' % (src, dest)
 302         result += '>'
 303         return result
 304
 305 class IpaReferencePrinter:
 306     def __init__(self, gdbval):
 307         self.gdbval = gdbval
 308
 309     def to_string (self):
 310         result = '<ipa_ref* 0x%x' % intptr(self.gdbval)
 311         if intptr(self.gdbval):
 312             src = SymtabNodePrinter(self.gdbval['referring']).to_string()
 313             dest = SymtabNodePrinter(self.gdbval['referred']).to_string()
 314             result += ' (%s -> %s:%s)' % (src, dest, str(self.gdbval['use']))
 315         result += '>'
 316         return result
 317
 318 ######################################################################
 319 # Dwarf DIE pretty-printers
 320 ######################################################################
 321
 322 class DWDieRefPrinter:
 323     def __init__(self, gdbval):
 324         self.gdbval = gdbval
 325
 326     def to_string (self):
 327         if intptr(self.gdbval) == 0:
 328             return '<dw_die_ref 0x0>'
 329         result = '<dw_die_ref 0x%x' % intptr(self.gdbval)
 330         result += ' %s' % self.gdbval['die_tag']
 331         if intptr(self.gdbval['die_parent']) != 0:
 332             result += ' <parent=0x%x %s>' % (intptr(self.gdbval['die_parent']),
 333                                              self.gdbval['die_parent']['die_tag'])
 334
 335         result += '>'
 336         return result
 337
 338 ######################################################################
 339
 340 class GimplePrinter:
 341     def __init__(self, gdbval):
 342         self.gdbval = gdbval
 343
 344     def to_string (self):
 345         if intptr(self.gdbval) == 0:
 346             return '<gimple 0x0>'
 347         val_gimple_code = self.gdbval['code']
 348         val_gimple_code_name = gdb.parse_and_eval('gimple_code_name')
 349         val_code_name = val_gimple_code_name[intptr(val_gimple_code)]
 350         result = '<%s 0x%x' % (val_code_name.string(),
 351                                intptr(self.gdbval))
 352         result += '>'
 353         return result
 354
 355 ######################################################################
 356 # CFG pretty-printers
 357 ######################################################################
 358
 359 def bb_index_to_str(index):
 360     if index == 0:
 361         return 'ENTRY'
 362     elif index == 1:
 363         return 'EXIT'
 364     else:
 365         return '%i' % index
 366
 367 class BasicBlockPrinter:
 368     def __init__(self, gdbval):
 369         self.gdbval = gdbval
 370
 371     def to_string (self):
 372         result = '<basic_block 0x%x' % intptr(self.gdbval)
 373         if intptr(self.gdbval):
 374             result += ' (%s)' % bb_index_to_str(intptr(self.gdbval['index']))
 375         result += '>'
 376         return result
 377
 378 class CfgEdgePrinter:
 379     def __init__(self, gdbval):
 380         self.gdbval = gdbval
 381
 382     def to_string (self):
 383         result = '<edge 0x%x' % intptr(self.gdbval)
 384         if intptr(self.gdbval):
 385             src = bb_index_to_str(intptr(self.gdbval['src']['index']))
 386             dest = bb_index_to_str(intptr(self.gdbval['dest']['index']))
 387             result += ' (%s -> %s)' % (src, dest)
 388         result += '>'
 389         return result
 390
 391 ######################################################################
 392
 393 class Rtx:
 394     def __init__(self, gdbval):
 395         self.gdbval = gdbval
 396
 397     def GET_CODE(self):
 398         return self.gdbval['code']
 399
 400 def GET_RTX_LENGTH(code):
 401     val_rtx_length = gdb.parse_and_eval('rtx_length')
 402     return intptr(val_rtx_length[code])
 403
 404 def GET_RTX_NAME(code):
 405     val_rtx_name = gdb.parse_and_eval('rtx_name')
 406     return val_rtx_name[code].string()
 407
 408 def GET_RTX_FORMAT(code):
 409     val_rtx_format = gdb.parse_and_eval('rtx_format')
 410     return val_rtx_format[code].string()
 411
 412 class RtxPrinter:
 413     def __init__(self, gdbval):
 414         self.gdbval = gdbval
 415         self.rtx = Rtx(gdbval)
 416
 417     def to_string (self):
 418         """
 419         For now, a cheap kludge: invoke the inferior's print
 420         function to get a string to use the user, and return an empty
 421         string for gdb
 422         """
 423         # We use print_inline_rtx to avoid a trailing newline
 424         gdb.execute('call print_inline_rtx (stderr, (const_rtx) %s, 0)'
 425                     % intptr(self.gdbval))
 426         return ''
 427
 428         # or by hand; based on gcc/print-rtl.c:print_rtx
 429         result = ('<rtx_def 0x%x'
 430                   % (intptr(self.gdbval)))
 431         code = self.rtx.GET_CODE()
 432         result += ' (%s' % GET_RTX_NAME(code)
 433         format_ = GET_RTX_FORMAT(code)
 434         for i in range(GET_RTX_LENGTH(code)):
 435             print(format_[i])
 436         result += ')>'
 437         return result
 438
 439 ######################################################################
 440
 441 class PassPrinter:
 442     def __init__(self, gdbval):
 443         self.gdbval = gdbval
 444
 445     def to_string (self):
 446         result = '<opt_pass* 0x%x' % intptr(self.gdbval)
 447         if intptr(self.gdbval):
 448             result += (' "%s"(%i)'
 449                        % (self.gdbval['name'].string(),
 450                           intptr(self.gdbval['static_pass_number'])))
 451         result += '>'
 452         return result
 453
 454 ######################################################################
 455
 456 class VecPrinter:
 457     #    -ex "up" -ex "p bb->preds"
 458     def __init__(self, gdbval):
 459         self.gdbval = gdbval
 460
 461     def display_hint (self):
 462         return 'array'
 463
 464     def to_string (self):
 465         # A trivial implementation; prettyprinting the contents is done
 466         # by gdb calling the "children" method below.
 467         return '0x%x' % intptr(self.gdbval)
 468
 469     def children (self):
 470         if intptr(self.gdbval) == 0:
 471             return
 472         m_vecpfx = self.gdbval['m_vecpfx']
 473         m_num = m_vecpfx['m_num']
 474         val = self.gdbval
 475         typ = val.type
 476         if typ.code == gdb.TYPE_CODE_PTR:
 477             typ = typ.target()
 478         else:
 479             val = val.address
 480         typ_T = typ.template_argument(0) # the type T
 481         vecdata = (val + 1).cast(typ_T.pointer())
 482         for i in range(m_num):
 483             yield ('[%d]' % i, vecdata[i])
 484
 485 ######################################################################
 486
 487 class MachineModePrinter:
 488     def __init__(self, gdbval):
 489         self.gdbval = gdbval
 490
 491     def to_string (self):
 492         name = str(self.gdbval['m_mode'])
 493         return name[2:] if name.startswith('E_') else name
 494
 495 ######################################################################
 496
 497 class OptMachineModePrinter:
 498     def __init__(self, gdbval):
 499         self.gdbval = gdbval
 500
 501     def to_string (self):
 502         name = str(self.gdbval['m_mode'])
 503         if name == 'E_VOIDmode':
 504             return '<None>'
 505         return name[2:] if name.startswith('E_') else name
 506
 507 ######################################################################
 508
 509 # TODO:
 510 #   * hashtab
 511 #   * location_t
 512
 513 class GdbSubprinter(gdb.printing.SubPrettyPrinter):
 514     def __init__(self, name, class_):
 515         super(GdbSubprinter, self).__init__(name)
 516         self.class_ = class_
 517
 518     def handles_type(self, str_type):
 519         raise NotImplementedError
 520
 521 class GdbSubprinterTypeList(GdbSubprinter):
 522     """
 523     A GdbSubprinter that handles a specific set of types
 524     """
 525     def __init__(self, str_types, name, class_):
 526         super(GdbSubprinterTypeList, self).__init__(name, class_)
 527         self.str_types = frozenset(str_types)
 528
 529     def handles_type(self, str_type):
 530         return str_type in self.str_types
 531
 532 class GdbSubprinterRegex(GdbSubprinter):
 533     """
 534     A GdbSubprinter that handles types that match a regex
 535     """
 536     def __init__(self, regex, name, class_):
 537         super(GdbSubprinterRegex, self).__init__(name, class_)
 538         self.regex = re.compile(regex)
 539
 540     def handles_type(self, str_type):
 541         return self.regex.match(str_type)
 542
 543 class GdbPrettyPrinters(gdb.printing.PrettyPrinter):
 544     def __init__(self, name):
 545         super(GdbPrettyPrinters, self).__init__(name, [])
 546
 547     def add_printer_for_types(self, types, name, class_):
 548         self.subprinters.append(GdbSubprinterTypeList(types, name, class_))
 549
 550     def add_printer_for_regex(self, regex, name, class_):
 551         self.subprinters.append(GdbSubprinterRegex(regex, name, class_))
 552
 553     def __call__(self, gdbval):
 554         type_ = gdbval.type.unqualified()
 555         str_type = str(type_)
 556         for printer in self.subprinters:
 557             if printer.enabled and printer.handles_type(str_type):
 558                 return printer.class_(gdbval)
 559
 560         # Couldn't find a pretty printer (or it was disabled):
 561         return None
 562
 563
 564 def build_pretty_printer():
 565     pp = GdbPrettyPrinters('gcc')
 566     pp.add_printer_for_types(['tree', 'const_tree'],
 567                              'tree', TreePrinter)
 568     pp.add_printer_for_types(['cgraph_node *', 'varpool_node *', 'symtab_node *'],
 569                              'symtab_node', SymtabNodePrinter)
 570     pp.add_printer_for_types(['cgraph_edge *'],
 571                              'cgraph_edge', CgraphEdgePrinter)
 572     pp.add_printer_for_types(['ipa_ref *'],
 573                              'ipa_ref', IpaReferencePrinter)
 574     pp.add_printer_for_types(['dw_die_ref'],
 575                              'dw_die_ref', DWDieRefPrinter)
 576     pp.add_printer_for_types(['gimple', 'gimple *',
 577
 578                               # Keep this in the same order as gimple.def:
 579                               'gimple_cond', 'const_gimple_cond',
 580                               'gimple_statement_cond *',
 581                               'gimple_debug', 'const_gimple_debug',
 582                               'gimple_statement_debug *',
 583                               'gimple_label', 'const_gimple_label',
 584                               'gimple_statement_label *',
 585                               'gimple_switch', 'const_gimple_switch',
 586                               'gimple_statement_switch *',
 587                               'gimple_assign', 'const_gimple_assign',
 588                               'gimple_statement_assign *',
 589                               'gimple_bind', 'const_gimple_bind',
 590                               'gimple_statement_bind *',
 591                               'gimple_phi', 'const_gimple_phi',
 592                               'gimple_statement_phi *'],
 593
 594                              'gimple',
 595                              GimplePrinter)
 596     pp.add_printer_for_types(['basic_block', 'basic_block_def *'],
 597                              'basic_block',
 598                              BasicBlockPrinter)
 599     pp.add_printer_for_types(['edge', 'edge_def *'],
 600                              'edge',
 601                              CfgEdgePrinter)
 602     pp.add_printer_for_types(['rtx_def *'], 'rtx_def', RtxPrinter)
 603     pp.add_printer_for_types(['opt_pass *'], 'opt_pass', PassPrinter)
 604
 605     pp.add_printer_for_regex(r'vec<(\S+), (\S+), (\S+)> \*',
 606                              'vec',
 607                              VecPrinter)
 608
 609     pp.add_printer_for_regex(r'opt_mode<(\S+)>',
 610                              'opt_mode', OptMachineModePrinter)
 611     pp.add_printer_for_types(['opt_scalar_int_mode',
 612                               'opt_scalar_float_mode',
 613                               'opt_scalar_mode'],
 614                              'opt_mode', OptMachineModePrinter)
 615     pp.add_printer_for_regex(r'pod_mode<(\S+)>',
 616                              'pod_mode', MachineModePrinter)
 617     pp.add_printer_for_types(['scalar_int_mode_pod',
 618                               'scalar_mode_pod'],
 619                              'pod_mode', MachineModePrinter)
 620     for mode in ('scalar_mode', 'scalar_int_mode', 'scalar_float_mode',
 621                  'complex_mode'):
 622         pp.add_printer_for_types([mode], mode, MachineModePrinter)
 623
 624     return pp
 625
 626 gdb.printing.register_pretty_printer(
 627     gdb.current_objfile(),
 628     build_pretty_printer(),
 629     replace=True)
 630
 631 def find_gcc_source_dir():
 632     # Use location of global "g" to locate the source tree
 633     sym_g = gdb.lookup_global_symbol('g')
 634     path = sym_g.symtab.filename # e.g. '../../src/gcc/context.h'
 635     srcdir = os.path.split(path)[0] # e.g. '../../src/gcc'
 636     return srcdir
 637
 638 class PassNames:
 639     """Parse passes.def, gathering a list of pass class names"""
 640     def __init__(self):
 641         srcdir = find_gcc_source_dir()
 642         self.names = []
 643         with open(os.path.join(srcdir, 'passes.def')) as f:
 644             for line in f:
 645                 m = re.match(r'\s*NEXT_PASS \(([^,]+).*\);', line)
 646                 if m:
 647                     self.names.append(m.group(1))
 648
 649 class BreakOnPass(gdb.Command):
 650     """
 651     A custom command for putting breakpoints on the execute hook of passes.
 652     This is largely a workaround for issues with tab-completion in gdb when
 653     setting breakpoints on methods on classes within anonymous namespaces.
 654
 655     Example of use: putting a breakpoint on "final"
 656       (gdb) break-on-pass
 657     Press <TAB>; it autocompletes to "pass_":
 658       (gdb) break-on-pass pass_
 659     Press <TAB>:
 660       Display all 219 possibilities? (y or n)
 661     Press "n"; then type "f":
 662       (gdb) break-on-pass pass_f
 663     Press <TAB> to autocomplete to pass classnames beginning with "pass_f":
 664       pass_fast_rtl_dce              pass_fold_builtins
 665       pass_feedback_split_functions  pass_forwprop
 666       pass_final                     pass_fre
 667       pass_fixup_cfg                 pass_free_cfg
 668     Type "in<TAB>" to complete to "pass_final":
 669       (gdb) break-on-pass pass_final
 670     ...and hit <RETURN>:
 671       Breakpoint 6 at 0x8396ba: file ../../src/gcc/final.c, line 4526.
 672     ...and we have a breakpoint set; continue execution:
 673       (gdb) cont
 674       Continuing.
 675       Breakpoint 6, (anonymous namespace)::pass_final::execute (this=0x17fb990) at ../../src/gcc/final.c:4526
 676       4526        virtual unsigned int execute (function *) { return rest_of_handle_final (); }
 677     """
 678     def __init__(self):
 679         gdb.Command.__init__(self, 'break-on-pass', gdb.COMMAND_BREAKPOINTS)
 680         self.pass_names = None
 681
 682     def complete(self, text, word):
 683         # Lazily load pass names:
 684         if not self.pass_names:
 685             self.pass_names = PassNames()
 686
 687         return [name
 688                 for name in sorted(self.pass_names.names)
 689                 if name.startswith(text)]
 690
 691     def invoke(self, arg, from_tty):
 692         sym = '(anonymous namespace)::%s::execute' % arg
 693         breakpoint = gdb.Breakpoint(sym)
 694
 695 BreakOnPass()
 696
 697 class DumpFn(gdb.Command):
 698     """
 699     A custom command to dump a gimple/rtl function to file.  By default, it
 700     dumps the current function using 0 as dump_flags, but the function and flags
 701     can also be specified. If /f <file> are passed as the first two arguments,
 702     the dump is written to that file.  Otherwise, a temporary file is created
 703     and opened in the text editor specified in the EDITOR environment variable.
 704
 705     Examples of use:
 706       (gdb) dump-fn
 707       (gdb) dump-fn /f foo.1.txt
 708       (gdb) dump-fn cfun->decl
 709       (gdb) dump-fn /f foo.1.txt cfun->decl
 710       (gdb) dump-fn cfun->decl 0
 711       (gdb) dump-fn cfun->decl dump_flags
 712     """
 713
 714     def __init__(self):
 715         gdb.Command.__init__(self, 'dump-fn', gdb.COMMAND_USER)
 716
 717     def invoke(self, arg, from_tty):
 718         # Parse args, check number of args
 719         args = gdb.string_to_argv(arg)
 720         if len(args) >= 1 and args[0] == "/f":
 721             if len(args) == 1:
 722                 print ("Missing file argument")
 723                 return
 724             filename = args[1]
 725             editor_mode = False
 726             base_arg = 2
 727         else:
 728             editor = os.getenv("EDITOR", "")
 729             if editor == "":
 730                 print ("EDITOR environment variable not defined")
 731                 return
 732             editor_mode = True
 733             base_arg = 0
 734         if len(args) - base_arg > 2:
 735             print ("Too many arguments")
 736             return
 737
 738         # Set func
 739         if len(args) - base_arg >= 1:
 740             funcname = args[base_arg]
 741             printfuncname = "function %s" % funcname
 742         else:
 743             funcname = "cfun ? cfun->decl : current_function_decl"
 744             printfuncname = "current function"
 745         func = gdb.parse_and_eval(funcname)
 746         if func == 0:
 747             print ("Could not find %s" % printfuncname)
 748             return
 749         func = "(tree)%u" % func
 750
 751         # Set flags
 752         if len(args) - base_arg >= 2:
 753             flags = gdb.parse_and_eval(args[base_arg + 1])
 754         else:
 755             flags = 0
 756
 757         # Get tempory file, if necessary
 758         if editor_mode:
 759             f = tempfile.NamedTemporaryFile(delete=False, suffix=".txt")
 760             filename = f.name
 761             f.close()
 762
 763         # Open file
 764         fp = gdb.parse_and_eval("(FILE *) fopen (\"%s\", \"w\")" % filename)
 765         if fp == 0:
 766             print ("Could not open file: %s" % filename)
 767             return
 768
 769         # Dump function to file
 770         _ = gdb.parse_and_eval("dump_function_to_file (%s, %s, %u)" %
 771                                (func, fp, flags))
 772
 773         # Close file
 774         ret = gdb.parse_and_eval("(int) fclose (%s)" % fp)
 775         if ret != 0:
 776             print ("Could not close file: %s" % filename)
 777             return
 778
 779         # Open file in editor, if necessary
 780         if editor_mode:
 781             os.system("( %s \"%s\"; rm \"%s\" ) &" %
 782                       (editor, filename, filename))
 783
 784 DumpFn()
 785
 786 class DotFn(gdb.Command):
 787     """
 788     A custom command to show a gimple/rtl function control flow graph.
 789     By default, it show the current function, but the function can also be
 790     specified.
 791
 792     Examples of use:
 793       (gdb) dot-fn
 794       (gdb) dot-fn cfun
 795       (gdb) dot-fn cfun 0
 796       (gdb) dot-fn cfun dump_flags
 797     """
 798     def __init__(self):
 799         gdb.Command.__init__(self, 'dot-fn', gdb.COMMAND_USER)
 800
 801     def invoke(self, arg, from_tty):
 802         # Parse args, check number of args
 803         args = gdb.string_to_argv(arg)
 804         if len(args) > 2:
 805             print("Too many arguments")
 806             return
 807
 808         # Set func
 809         if len(args) >= 1:
 810             funcname = args[0]
 811             printfuncname = "function %s" % funcname
 812         else:
 813             funcname = "cfun"
 814             printfuncname = "current function"
 815         func = gdb.parse_and_eval(funcname)
 816         if func == 0:
 817             print("Could not find %s" % printfuncname)
 818             return
 819         func = "(struct function *)%s" % func
 820
 821         # Set flags
 822         if len(args) >= 2:
 823             flags = gdb.parse_and_eval(args[1])
 824         else:
 825             flags = 0
 826
 827         # Get temp file
 828         f = tempfile.NamedTemporaryFile(delete=False)
 829         filename = f.name
 830
 831         # Close and reopen temp file to get C FILE*
 832         f.close()
 833         fp = gdb.parse_and_eval("(FILE *) fopen (\"%s\", \"w\")" % filename)
 834         if fp == 0:
 835             print("Cannot open temp file")
 836             return
 837
 838         # Write graph to temp file
 839         _ = gdb.parse_and_eval("start_graph_dump (%s, \"<debug>\")" % fp)
 840         _ = gdb.parse_and_eval("print_graph_cfg (%s, %s, %u)"
 841                                % (fp, func, flags))
 842         _ = gdb.parse_and_eval("end_graph_dump (%s)" % fp)
 843
 844         # Close temp file
 845         ret = gdb.parse_and_eval("(int) fclose (%s)" % fp)
 846         if ret != 0:
 847             print("Could not close temp file: %s" % filename)
 848             return
 849
 850         # Show graph in temp file
 851         os.system("( dot -Tx11 \"%s\"; rm \"%s\" ) &" % (filename, filename))
 852
 853 DotFn()
 854
 855 print('Successfully loaded GDB hooks for GCC')