gcc/gdbhooks.py

   1 # Python hooks for gdb for debugging GCC
   2 # Copyright (C) 2013-2023 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 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         # extern const enum tree_code_class tree_code_type[];
 224         # #define TREE_CODE_CLASS(CODE) tree_code_type[(int) (CODE)]
 225
 226         if val_TREE_CODE == 0xa5a5:
 227             return '<ggc_freed 0x%x>' % intptr(self.gdbval)
 228
 229         val_tree_code_type = gdb.parse_and_eval('tree_code_type')
 230         val_tclass = val_tree_code_type[val_TREE_CODE]
 231
 232         val_tree_code_name = gdb.parse_and_eval('tree_code_name')
 233         val_code_name = val_tree_code_name[intptr(val_TREE_CODE)]
 234         #print(val_code_name.string())
 235
 236         try:
 237             result = '<%s 0x%x' % (val_code_name.string(), intptr(self.gdbval))
 238         except:
 239             return '<tree 0x%x>' % intptr(self.gdbval)
 240         if intptr(val_tclass) == tcc_declaration:
 241             tree_DECL_NAME = self.node.DECL_NAME()
 242             if tree_DECL_NAME.is_nonnull():
 243                  result += ' %s' % tree_DECL_NAME.IDENTIFIER_POINTER()
 244             else:
 245                 pass # TODO: labels etc
 246         elif intptr(val_tclass) == tcc_type:
 247             tree_TYPE_NAME = Tree(self.gdbval['type_common']['name'])
 248             if tree_TYPE_NAME.is_nonnull():
 249                 if tree_TYPE_NAME.TREE_CODE() == IDENTIFIER_NODE:
 250                     result += ' %s' % tree_TYPE_NAME.IDENTIFIER_POINTER()
 251                 elif tree_TYPE_NAME.TREE_CODE() == TYPE_DECL:
 252                     if tree_TYPE_NAME.DECL_NAME().is_nonnull():
 253                         result += ' %s' % tree_TYPE_NAME.DECL_NAME().IDENTIFIER_POINTER()
 254         if self.node.TREE_CODE() == IDENTIFIER_NODE:
 255             result += ' %s' % self.node.IDENTIFIER_POINTER()
 256         elif self.node.TREE_CODE() == SSA_NAME:
 257             result += ' %u' % self.gdbval['base']['u']['version']
 258         # etc
 259         result += '>'
 260         return result
 261
 262 ######################################################################
 263 # Callgraph pretty-printers
 264 ######################################################################
 265
 266 class SymtabNodePrinter:
 267     def __init__(self, gdbval):
 268         self.gdbval = gdbval
 269
 270     def to_string (self):
 271         t = str(self.gdbval.type)
 272         result = '<%s 0x%x' % (t, intptr(self.gdbval))
 273         if intptr(self.gdbval):
 274             # symtab_node::name calls lang_hooks.decl_printable_name
 275             # default implementation (lhd_decl_printable_name) is:
 276             #    return IDENTIFIER_POINTER (DECL_NAME (decl));
 277             tree_decl = Tree(self.gdbval['decl'])
 278             result += ' "%s"/%d' % (tree_decl.DECL_NAME().IDENTIFIER_POINTER(), self.gdbval['order'])
 279         result += '>'
 280         return result
 281
 282 class CgraphEdgePrinter:
 283     def __init__(self, gdbval):
 284         self.gdbval = gdbval
 285
 286     def to_string (self):
 287         result = '<cgraph_edge* 0x%x' % intptr(self.gdbval)
 288         if intptr(self.gdbval):
 289             src = SymtabNodePrinter(self.gdbval['caller']).to_string()
 290             dest = SymtabNodePrinter(self.gdbval['callee']).to_string()
 291             result += ' (%s -> %s)' % (src, dest)
 292         result += '>'
 293         return result
 294
 295 class IpaReferencePrinter:
 296     def __init__(self, gdbval):
 297         self.gdbval = gdbval
 298
 299     def to_string (self):
 300         result = '<ipa_ref* 0x%x' % intptr(self.gdbval)
 301         if intptr(self.gdbval):
 302             src = SymtabNodePrinter(self.gdbval['referring']).to_string()
 303             dest = SymtabNodePrinter(self.gdbval['referred']).to_string()
 304             result += ' (%s -> %s:%s)' % (src, dest, str(self.gdbval['use']))
 305         result += '>'
 306         return result
 307
 308 ######################################################################
 309 # Dwarf DIE pretty-printers
 310 ######################################################################
 311
 312 class DWDieRefPrinter:
 313     def __init__(self, gdbval):
 314         self.gdbval = gdbval
 315
 316     def to_string (self):
 317         if intptr(self.gdbval) == 0:
 318             return '<dw_die_ref 0x0>'
 319         result = '<dw_die_ref 0x%x' % intptr(self.gdbval)
 320         result += ' %s' % self.gdbval['die_tag']
 321         if intptr(self.gdbval['die_parent']) != 0:
 322             result += ' <parent=0x%x %s>' % (intptr(self.gdbval['die_parent']),
 323                                              self.gdbval['die_parent']['die_tag'])
 324
 325         result += '>'
 326         return result
 327
 328 ######################################################################
 329
 330 class GimplePrinter:
 331     def __init__(self, gdbval):
 332         self.gdbval = gdbval
 333
 334     def to_string (self):
 335         if intptr(self.gdbval) == 0:
 336             return '<gimple 0x0>'
 337         val_gimple_code = self.gdbval['code']
 338         val_gimple_code_name = gdb.parse_and_eval('gimple_code_name')
 339         val_code_name = val_gimple_code_name[intptr(val_gimple_code)]
 340         result = '<%s 0x%x' % (val_code_name.string(),
 341                                intptr(self.gdbval))
 342         result += '>'
 343         return result
 344
 345 ######################################################################
 346 # CFG pretty-printers
 347 ######################################################################
 348
 349 def bb_index_to_str(index):
 350     if index == 0:
 351         return 'ENTRY'
 352     elif index == 1:
 353         return 'EXIT'
 354     else:
 355         return '%i' % index
 356
 357 class BasicBlockPrinter:
 358     def __init__(self, gdbval):
 359         self.gdbval = gdbval
 360
 361     def to_string (self):
 362         result = '<basic_block 0x%x' % intptr(self.gdbval)
 363         if intptr(self.gdbval):
 364             result += ' (%s)' % bb_index_to_str(intptr(self.gdbval['index']))
 365         result += '>'
 366         return result
 367
 368 class CfgEdgePrinter:
 369     def __init__(self, gdbval):
 370         self.gdbval = gdbval
 371
 372     def to_string (self):
 373         result = '<edge 0x%x' % intptr(self.gdbval)
 374         if intptr(self.gdbval):
 375             src = bb_index_to_str(intptr(self.gdbval['src']['index']))
 376             dest = bb_index_to_str(intptr(self.gdbval['dest']['index']))
 377             result += ' (%s -> %s)' % (src, dest)
 378         result += '>'
 379         return result
 380
 381 ######################################################################
 382
 383 class Rtx:
 384     def __init__(self, gdbval):
 385         self.gdbval = gdbval
 386
 387     def GET_CODE(self):
 388         return self.gdbval['code']
 389
 390 def GET_RTX_LENGTH(code):
 391     val_rtx_length = gdb.parse_and_eval('rtx_length')
 392     return intptr(val_rtx_length[code])
 393
 394 def GET_RTX_NAME(code):
 395     val_rtx_name = gdb.parse_and_eval('rtx_name')
 396     return val_rtx_name[code].string()
 397
 398 def GET_RTX_FORMAT(code):
 399     val_rtx_format = gdb.parse_and_eval('rtx_format')
 400     return val_rtx_format[code].string()
 401
 402 class RtxPrinter:
 403     def __init__(self, gdbval):
 404         self.gdbval = gdbval
 405         self.rtx = Rtx(gdbval)
 406
 407     def to_string (self):
 408         """
 409         For now, a cheap kludge: invoke the inferior's print
 410         function to get a string to use the user, and return an empty
 411         string for gdb
 412         """
 413         # We use print_inline_rtx to avoid a trailing newline
 414         gdb.execute('call print_inline_rtx (stderr, (const_rtx) %s, 0)'
 415                     % intptr(self.gdbval))
 416         return ''
 417
 418         # or by hand; based on gcc/print-rtl.c:print_rtx
 419         result = ('<rtx_def 0x%x'
 420                   % (intptr(self.gdbval)))
 421         code = self.rtx.GET_CODE()
 422         result += ' (%s' % GET_RTX_NAME(code)
 423         format_ = GET_RTX_FORMAT(code)
 424         for i in range(GET_RTX_LENGTH(code)):
 425             print(format_[i])
 426         result += ')>'
 427         return result
 428
 429 ######################################################################
 430
 431 class PassPrinter:
 432     def __init__(self, gdbval):
 433         self.gdbval = gdbval
 434
 435     def to_string (self):
 436         result = '<opt_pass* 0x%x' % intptr(self.gdbval)
 437         if intptr(self.gdbval):
 438             result += (' "%s"(%i)'
 439                        % (self.gdbval['name'].string(),
 440                           intptr(self.gdbval['static_pass_number'])))
 441         result += '>'
 442         return result
 443
 444 ######################################################################
 445
 446 class VecPrinter:
 447     #    -ex "up" -ex "p bb->preds"
 448     def __init__(self, gdbval):
 449         self.gdbval = gdbval
 450
 451     def display_hint (self):
 452         return 'array'
 453
 454     def to_string (self):
 455         # A trivial implementation; prettyprinting the contents is done
 456         # by gdb calling the "children" method below.
 457         return '0x%x' % intptr(self.gdbval)
 458
 459     def children (self):
 460         if intptr(self.gdbval) == 0:
 461             return
 462         m_vecpfx = self.gdbval['m_vecpfx']
 463         m_num = m_vecpfx['m_num']
 464         m_vecdata = self.gdbval['m_vecdata']
 465         for i in range(m_num):
 466             yield ('[%d]' % i, m_vecdata[i])
 467
 468 ######################################################################
 469
 470 class MachineModePrinter:
 471     def __init__(self, gdbval):
 472         self.gdbval = gdbval
 473
 474     def to_string (self):
 475         name = str(self.gdbval['m_mode'])
 476         return name[2:] if name.startswith('E_') else name
 477
 478 ######################################################################
 479
 480 class OptMachineModePrinter:
 481     def __init__(self, gdbval):
 482         self.gdbval = gdbval
 483
 484     def to_string (self):
 485         name = str(self.gdbval['m_mode'])
 486         if name == 'E_VOIDmode':
 487             return '<None>'
 488         return name[2:] if name.startswith('E_') else name
 489
 490 ######################################################################
 491
 492 # TODO:
 493 #   * hashtab
 494 #   * location_t
 495
 496 class GdbSubprinter(gdb.printing.SubPrettyPrinter):
 497     def __init__(self, name, class_):
 498         super(GdbSubprinter, self).__init__(name)
 499         self.class_ = class_
 500
 501     def handles_type(self, str_type):
 502         raise NotImplementedError
 503
 504 class GdbSubprinterTypeList(GdbSubprinter):
 505     """
 506     A GdbSubprinter that handles a specific set of types
 507     """
 508     def __init__(self, str_types, name, class_):
 509         super(GdbSubprinterTypeList, self).__init__(name, class_)
 510         self.str_types = frozenset(str_types)
 511
 512     def handles_type(self, str_type):
 513         return str_type in self.str_types
 514
 515 class GdbSubprinterRegex(GdbSubprinter):
 516     """
 517     A GdbSubprinter that handles types that match a regex
 518     """
 519     def __init__(self, regex, name, class_):
 520         super(GdbSubprinterRegex, self).__init__(name, class_)
 521         self.regex = re.compile(regex)
 522
 523     def handles_type(self, str_type):
 524         return self.regex.match(str_type)
 525
 526 class GdbPrettyPrinters(gdb.printing.PrettyPrinter):
 527     def __init__(self, name):
 528         super(GdbPrettyPrinters, self).__init__(name, [])
 529
 530     def add_printer_for_types(self, types, name, class_):
 531         self.subprinters.append(GdbSubprinterTypeList(types, name, class_))
 532
 533     def add_printer_for_regex(self, regex, name, class_):
 534         self.subprinters.append(GdbSubprinterRegex(regex, name, class_))
 535
 536     def __call__(self, gdbval):
 537         type_ = gdbval.type.unqualified()
 538         str_type = str(type_)
 539         for printer in self.subprinters:
 540             if printer.enabled and printer.handles_type(str_type):
 541                 return printer.class_(gdbval)
 542
 543         # Couldn't find a pretty printer (or it was disabled):
 544         return None
 545
 546
 547 def build_pretty_printer():
 548     pp = GdbPrettyPrinters('gcc')
 549     pp.add_printer_for_types(['tree', 'const_tree'],
 550                              'tree', TreePrinter)
 551     pp.add_printer_for_types(['cgraph_node *', 'varpool_node *', 'symtab_node *'],
 552                              'symtab_node', SymtabNodePrinter)
 553     pp.add_printer_for_types(['cgraph_edge *'],
 554                              'cgraph_edge', CgraphEdgePrinter)
 555     pp.add_printer_for_types(['ipa_ref *'],
 556                              'ipa_ref', IpaReferencePrinter)
 557     pp.add_printer_for_types(['dw_die_ref'],
 558                              'dw_die_ref', DWDieRefPrinter)
 559     pp.add_printer_for_types(['gimple', 'gimple *',
 560
 561                               # Keep this in the same order as gimple.def:
 562                               'gimple_cond', 'const_gimple_cond',
 563                               'gimple_statement_cond *',
 564                               'gimple_debug', 'const_gimple_debug',
 565                               'gimple_statement_debug *',
 566                               'gimple_label', 'const_gimple_label',
 567                               'gimple_statement_label *',
 568                               'gimple_switch', 'const_gimple_switch',
 569                               'gimple_statement_switch *',
 570                               'gimple_assign', 'const_gimple_assign',
 571                               'gimple_statement_assign *',
 572                               'gimple_bind', 'const_gimple_bind',
 573                               'gimple_statement_bind *',
 574                               'gimple_phi', 'const_gimple_phi',
 575                               'gimple_statement_phi *'],
 576
 577                              'gimple',
 578                              GimplePrinter)
 579     pp.add_printer_for_types(['basic_block', 'basic_block_def *'],
 580                              'basic_block',
 581                              BasicBlockPrinter)
 582     pp.add_printer_for_types(['edge', 'edge_def *'],
 583                              'edge',
 584                              CfgEdgePrinter)
 585     pp.add_printer_for_types(['rtx_def *'], 'rtx_def', RtxPrinter)
 586     pp.add_printer_for_types(['opt_pass *'], 'opt_pass', PassPrinter)
 587
 588     pp.add_printer_for_regex(r'vec<(\S+), (\S+), (\S+)> \*',
 589                              'vec',
 590                              VecPrinter)
 591
 592     pp.add_printer_for_regex(r'opt_mode<(\S+)>',
 593                              'opt_mode', OptMachineModePrinter)
 594     pp.add_printer_for_types(['opt_scalar_int_mode',
 595                               'opt_scalar_float_mode',
 596                               'opt_scalar_mode'],
 597                              'opt_mode', OptMachineModePrinter)
 598     pp.add_printer_for_regex(r'pod_mode<(\S+)>',
 599                              'pod_mode', MachineModePrinter)
 600     pp.add_printer_for_types(['scalar_int_mode_pod',
 601                               'scalar_mode_pod'],
 602                              'pod_mode', MachineModePrinter)
 603     for mode in ('scalar_mode', 'scalar_int_mode', 'scalar_float_mode',
 604                  'complex_mode'):
 605         pp.add_printer_for_types([mode], mode, MachineModePrinter)
 606
 607     return pp
 608
 609 gdb.printing.register_pretty_printer(
 610     gdb.current_objfile(),
 611     build_pretty_printer(),
 612     replace=True)
 613
 614 def find_gcc_source_dir():
 615     # Use location of global "g" to locate the source tree
 616     sym_g = gdb.lookup_global_symbol('g')
 617     path = sym_g.symtab.filename # e.g. '../../src/gcc/context.h'
 618     srcdir = os.path.split(path)[0] # e.g. '../../src/gcc'
 619     return srcdir
 620
 621 class PassNames:
 622     """Parse passes.def, gathering a list of pass class names"""
 623     def __init__(self):
 624         srcdir = find_gcc_source_dir()
 625         self.names = []
 626         with open(os.path.join(srcdir, 'passes.def')) as f:
 627             for line in f:
 628                 m = re.match('\s*NEXT_PASS \(([^,]+).*\);', line)
 629                 if m:
 630                     self.names.append(m.group(1))
 631
 632 class BreakOnPass(gdb.Command):
 633     """
 634     A custom command for putting breakpoints on the execute hook of passes.
 635     This is largely a workaround for issues with tab-completion in gdb when
 636     setting breakpoints on methods on classes within anonymous namespaces.
 637
 638     Example of use: putting a breakpoint on "final"
 639       (gdb) break-on-pass
 640     Press <TAB>; it autocompletes to "pass_":
 641       (gdb) break-on-pass pass_
 642     Press <TAB>:
 643       Display all 219 possibilities? (y or n)
 644     Press "n"; then type "f":
 645       (gdb) break-on-pass pass_f
 646     Press <TAB> to autocomplete to pass classnames beginning with "pass_f":
 647       pass_fast_rtl_dce              pass_fold_builtins
 648       pass_feedback_split_functions  pass_forwprop
 649       pass_final                     pass_fre
 650       pass_fixup_cfg                 pass_free_cfg
 651     Type "in<TAB>" to complete to "pass_final":
 652       (gdb) break-on-pass pass_final
 653     ...and hit <RETURN>:
 654       Breakpoint 6 at 0x8396ba: file ../../src/gcc/final.c, line 4526.
 655     ...and we have a breakpoint set; continue execution:
 656       (gdb) cont
 657       Continuing.
 658       Breakpoint 6, (anonymous namespace)::pass_final::execute (this=0x17fb990) at ../../src/gcc/final.c:4526
 659       4526        virtual unsigned int execute (function *) { return rest_of_handle_final (); }
 660     """
 661     def __init__(self):
 662         gdb.Command.__init__(self, 'break-on-pass', gdb.COMMAND_BREAKPOINTS)
 663         self.pass_names = None
 664
 665     def complete(self, text, word):
 666         # Lazily load pass names:
 667         if not self.pass_names:
 668             self.pass_names = PassNames()
 669
 670         return [name
 671                 for name in sorted(self.pass_names.names)
 672                 if name.startswith(text)]
 673
 674     def invoke(self, arg, from_tty):
 675         sym = '(anonymous namespace)::%s::execute' % arg
 676         breakpoint = gdb.Breakpoint(sym)
 677
 678 BreakOnPass()
 679
 680 class DumpFn(gdb.Command):
 681     """
 682     A custom command to dump a gimple/rtl function to file.  By default, it
 683     dumps the current function using 0 as dump_flags, but the function and flags
 684     can also be specified. If /f <file> are passed as the first two arguments,
 685     the dump is written to that file.  Otherwise, a temporary file is created
 686     and opened in the text editor specified in the EDITOR environment variable.
 687
 688     Examples of use:
 689       (gdb) dump-fn
 690       (gdb) dump-fn /f foo.1.txt
 691       (gdb) dump-fn cfun->decl
 692       (gdb) dump-fn /f foo.1.txt cfun->decl
 693       (gdb) dump-fn cfun->decl 0
 694       (gdb) dump-fn cfun->decl dump_flags
 695     """
 696
 697     def __init__(self):
 698         gdb.Command.__init__(self, 'dump-fn', gdb.COMMAND_USER)
 699
 700     def invoke(self, arg, from_tty):
 701         # Parse args, check number of args
 702         args = gdb.string_to_argv(arg)
 703         if len(args) >= 1 and args[0] == "/f":
 704             if len(args) == 1:
 705                 print ("Missing file argument")
 706                 return
 707             filename = args[1]
 708             editor_mode = False
 709             base_arg = 2
 710         else:
 711             editor = os.getenv("EDITOR", "")
 712             if editor == "":
 713                 print ("EDITOR environment variable not defined")
 714                 return
 715             editor_mode = True
 716             base_arg = 0
 717         if len(args) - base_arg > 2:
 718             print ("Too many arguments")
 719             return
 720
 721         # Set func
 722         if len(args) - base_arg >= 1:
 723             funcname = args[base_arg]
 724             printfuncname = "function %s" % funcname
 725         else:
 726             funcname = "cfun ? cfun->decl : current_function_decl"
 727             printfuncname = "current function"
 728         func = gdb.parse_and_eval(funcname)
 729         if func == 0:
 730             print ("Could not find %s" % printfuncname)
 731             return
 732         func = "(tree)%u" % func
 733
 734         # Set flags
 735         if len(args) - base_arg >= 2:
 736             flags = gdb.parse_and_eval(args[base_arg + 1])
 737         else:
 738             flags = 0
 739
 740         # Get tempory file, if necessary
 741         if editor_mode:
 742             f = tempfile.NamedTemporaryFile(delete=False, suffix=".txt")
 743             filename = f.name
 744             f.close()
 745
 746         # Open file
 747         fp = gdb.parse_and_eval("(FILE *) fopen (\"%s\", \"w\")" % filename)
 748         if fp == 0:
 749             print ("Could not open file: %s" % filename)
 750             return
 751
 752         # Dump function to file
 753         _ = gdb.parse_and_eval("dump_function_to_file (%s, %s, %u)" %
 754                                (func, fp, flags))
 755
 756         # Close file
 757         ret = gdb.parse_and_eval("(int) fclose (%s)" % fp)
 758         if ret != 0:
 759             print ("Could not close file: %s" % filename)
 760             return
 761
 762         # Open file in editor, if necessary
 763         if editor_mode:
 764             os.system("( %s \"%s\"; rm \"%s\" ) &" %
 765                       (editor, filename, filename))
 766
 767 DumpFn()
 768
 769 class DotFn(gdb.Command):
 770     """
 771     A custom command to show a gimple/rtl function control flow graph.
 772     By default, it show the current function, but the function can also be
 773     specified.
 774
 775     Examples of use:
 776       (gdb) dot-fn
 777       (gdb) dot-fn cfun
 778       (gdb) dot-fn cfun 0
 779       (gdb) dot-fn cfun dump_flags
 780     """
 781     def __init__(self):
 782         gdb.Command.__init__(self, 'dot-fn', gdb.COMMAND_USER)
 783
 784     def invoke(self, arg, from_tty):
 785         # Parse args, check number of args
 786         args = gdb.string_to_argv(arg)
 787         if len(args) > 2:
 788             print("Too many arguments")
 789             return
 790
 791         # Set func
 792         if len(args) >= 1:
 793             funcname = args[0]
 794             printfuncname = "function %s" % funcname
 795         else:
 796             funcname = "cfun"
 797             printfuncname = "current function"
 798         func = gdb.parse_and_eval(funcname)
 799         if func == 0:
 800             print("Could not find %s" % printfuncname)
 801             return
 802         func = "(struct function *)%s" % func
 803
 804         # Set flags
 805         if len(args) >= 2:
 806             flags = gdb.parse_and_eval(args[1])
 807         else:
 808             flags = 0
 809
 810         # Get temp file
 811         f = tempfile.NamedTemporaryFile(delete=False)
 812         filename = f.name
 813
 814         # Close and reopen temp file to get C FILE*
 815         f.close()
 816         fp = gdb.parse_and_eval("(FILE *) fopen (\"%s\", \"w\")" % filename)
 817         if fp == 0:
 818             print("Cannot open temp file")
 819             return
 820
 821         # Write graph to temp file
 822         _ = gdb.parse_and_eval("start_graph_dump (%s, \"<debug>\")" % fp)
 823         _ = gdb.parse_and_eval("print_graph_cfg (%s, %s, %u)"
 824                                % (fp, func, flags))
 825         _ = gdb.parse_and_eval("end_graph_dump (%s)" % fp)
 826
 827         # Close temp file
 828         ret = gdb.parse_and_eval("(int) fclose (%s)" % fp)
 829         if ret != 0:
 830             print("Could not close temp file: %s" % filename)
 831             return
 832
 833         # Show graph in temp file
 834         os.system("( dot -Tx11 \"%s\"; rm \"%s\" ) &" % (filename, filename))
 835
 836 DotFn()
 837
 838 print('Successfully loaded GDB hooks for GCC')