1# Python hooks for gdb for debugging GCC 2# Copyright (C) 2013-2018 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""" 23Enabling the debugging hooks 24---------------------------- 25gcc/configure (from configure.ac) generates a .gdbinit within the "gcc" 26subdirectory of the build directory, and when run by gdb, this imports 27gcc/gdbhooks.py from the source directory, injecting useful Python code 28into gdb. 29 30You 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' 32as a protection against untrustworthy python scripts. See 33 http://sourceware.org/gdb/onlinedocs/gdb/Auto_002dloading-safe-path.html 34 35The fix is to mark the paths of the build/gcc directory as trustworthy. 36An 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 38for the build directories for your various checkouts of gcc. 39 40If it's working, you should see the message: 41 Successfully loaded GDB hooks for GCC 42as gdb starts up. 43 44During development, I've been manually invoking the code in this way, as a 45precanned 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 54Examples of output using the pretty-printers 55-------------------------------------------- 56Pointer values are generally shown in the form: 57 <type address extra_info> 58 59For example, an opt_pass* might appear as: 60 (gdb) p pass 61 $2 = <opt_pass* 0x188b600 "expand"(170)> 62 63The name of the pass is given ("expand"), together with the 64static_pass_number. 65 66Note 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 71and you can suppress pretty-printers using /r (for "raw"): 72 (gdb) p /r pass 73 $3 = (opt_pass *) 0x188b600 74 75Basic blocks are shown with their index in parentheses, apart from the 76CFG'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 84CFG edges are shown with the src and dest blocks given in parentheses: 85 (gdb) p e 86 $1 = <edge 0x7ffff043f118 (ENTRY -> 6)> 87 88Tree nodes are printed using Python code that emulates print_node_brief, 89running in gdb, rather than in the inferior: 90 (gdb) p cfun->decl 91 $1 = <function_decl 0x7ffff0420b00 foo> 92For usability, the type is printed first (e.g. "function_decl"), rather 93than just "tree". 94 95RTL expressions use a kludge: they are pretty-printed by injecting 96calls 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 102This won't work for coredumps, and probably in other circumstances, but 103it's a quick way of getting lots of debuggability quickly. 104 105Callgraph nodes are printed with the name of the function decl, if 106available: 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 113Similarly for symtab_node and varpool_node classes. 114 115Cgraph 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 119IPA 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 122vec<> pointers are printed as the address followed by the elements in 123braces. Here's a length 2 vec: 124 (gdb) p bb->preds 125 $18 = 0x7ffff0428b68 = {<edge 0x7ffff044d380 (3 -> 5)>, <edge 0x7ffff044d3b8 (4 -> 5)>} 126 127and here's a length 1 vec: 128 (gdb) p bb->succs 129 $19 = 0x7ffff0428bb8 = {<edge 0x7ffff044d3f0 (5 -> EXIT)>} 130 131You cannot yet use array notation [] to access the elements within the 132vector: attempting to do so instead gives you the vec itself (for vec[0]), 133or a (probably) invalid cast to vec<> for the memory after the vec (for 134vec[1] onwards). 135 136Instead (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""" 142import os.path 143import re 144import sys 145import tempfile 146 147import gdb 148import gdb.printing 149import gdb.types 150 151# Convert "enum tree_code" (tree.def and tree.h) to a dict: 152tree_code_dict = gdb.types.make_enum_dict(gdb.lookup_type('enum tree_code')) 153 154# ...and look up specific values for use later: 155IDENTIFIER_NODE = tree_code_dict['IDENTIFIER_NODE'] 156TYPE_DECL = tree_code_dict['TYPE_DECL'] 157 158# Similarly for "enum tree_code_class" (tree.h): 159tree_code_class_dict = gdb.types.make_enum_dict(gdb.lookup_type('enum tree_code_class')) 160tcc_type = tree_code_class_dict['tcc_type'] 161tcc_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. 166def intptr(gdbval): 167 return long(gdbval) if sys.version_info.major == 2 else int(gdbval) 168 169class 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 206class 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 result = '<%s 0x%x' % (val_code_name.string(), intptr(self.gdbval)) 233 if intptr(val_tclass) == tcc_declaration: 234 tree_DECL_NAME = self.node.DECL_NAME() 235 if tree_DECL_NAME.is_nonnull(): 236 result += ' %s' % tree_DECL_NAME.IDENTIFIER_POINTER() 237 else: 238 pass # TODO: labels etc 239 elif intptr(val_tclass) == tcc_type: 240 tree_TYPE_NAME = Tree(self.gdbval['type_common']['name']) 241 if tree_TYPE_NAME.is_nonnull(): 242 if tree_TYPE_NAME.TREE_CODE() == IDENTIFIER_NODE: 243 result += ' %s' % tree_TYPE_NAME.IDENTIFIER_POINTER() 244 elif tree_TYPE_NAME.TREE_CODE() == TYPE_DECL: 245 if tree_TYPE_NAME.DECL_NAME().is_nonnull(): 246 result += ' %s' % tree_TYPE_NAME.DECL_NAME().IDENTIFIER_POINTER() 247 if self.node.TREE_CODE() == IDENTIFIER_NODE: 248 result += ' %s' % self.node.IDENTIFIER_POINTER() 249 # etc 250 result += '>' 251 return result 252 253###################################################################### 254# Callgraph pretty-printers 255###################################################################### 256 257class SymtabNodePrinter: 258 def __init__(self, gdbval): 259 self.gdbval = gdbval 260 261 def to_string (self): 262 t = str(self.gdbval.type) 263 result = '<%s 0x%x' % (t, intptr(self.gdbval)) 264 if intptr(self.gdbval): 265 # symtab_node::name calls lang_hooks.decl_printable_name 266 # default implementation (lhd_decl_printable_name) is: 267 # return IDENTIFIER_POINTER (DECL_NAME (decl)); 268 tree_decl = Tree(self.gdbval['decl']) 269 result += ' "%s"/%d' % (tree_decl.DECL_NAME().IDENTIFIER_POINTER(), self.gdbval['order']) 270 result += '>' 271 return result 272 273class CgraphEdgePrinter: 274 def __init__(self, gdbval): 275 self.gdbval = gdbval 276 277 def to_string (self): 278 result = '<cgraph_edge* 0x%x' % intptr(self.gdbval) 279 if intptr(self.gdbval): 280 src = SymtabNodePrinter(self.gdbval['caller']).to_string() 281 dest = SymtabNodePrinter(self.gdbval['callee']).to_string() 282 result += ' (%s -> %s)' % (src, dest) 283 result += '>' 284 return result 285 286class IpaReferencePrinter: 287 def __init__(self, gdbval): 288 self.gdbval = gdbval 289 290 def to_string (self): 291 result = '<ipa_ref* 0x%x' % intptr(self.gdbval) 292 if intptr(self.gdbval): 293 src = SymtabNodePrinter(self.gdbval['referring']).to_string() 294 dest = SymtabNodePrinter(self.gdbval['referred']).to_string() 295 result += ' (%s -> %s:%s)' % (src, dest, str(self.gdbval['use'])) 296 result += '>' 297 return result 298 299###################################################################### 300# Dwarf DIE pretty-printers 301###################################################################### 302 303class DWDieRefPrinter: 304 def __init__(self, gdbval): 305 self.gdbval = gdbval 306 307 def to_string (self): 308 if intptr(self.gdbval) == 0: 309 return '<dw_die_ref 0x0>' 310 result = '<dw_die_ref 0x%x' % intptr(self.gdbval) 311 result += ' %s' % self.gdbval['die_tag'] 312 if intptr(self.gdbval['die_parent']) != 0: 313 result += ' <parent=0x%x %s>' % (intptr(self.gdbval['die_parent']), 314 self.gdbval['die_parent']['die_tag']) 315 316 result += '>' 317 return result 318 319###################################################################### 320 321class GimplePrinter: 322 def __init__(self, gdbval): 323 self.gdbval = gdbval 324 325 def to_string (self): 326 if intptr(self.gdbval) == 0: 327 return '<gimple 0x0>' 328 val_gimple_code = self.gdbval['code'] 329 val_gimple_code_name = gdb.parse_and_eval('gimple_code_name') 330 val_code_name = val_gimple_code_name[intptr(val_gimple_code)] 331 result = '<%s 0x%x' % (val_code_name.string(), 332 intptr(self.gdbval)) 333 result += '>' 334 return result 335 336###################################################################### 337# CFG pretty-printers 338###################################################################### 339 340def bb_index_to_str(index): 341 if index == 0: 342 return 'ENTRY' 343 elif index == 1: 344 return 'EXIT' 345 else: 346 return '%i' % index 347 348class BasicBlockPrinter: 349 def __init__(self, gdbval): 350 self.gdbval = gdbval 351 352 def to_string (self): 353 result = '<basic_block 0x%x' % intptr(self.gdbval) 354 if intptr(self.gdbval): 355 result += ' (%s)' % bb_index_to_str(intptr(self.gdbval['index'])) 356 result += '>' 357 return result 358 359class CfgEdgePrinter: 360 def __init__(self, gdbval): 361 self.gdbval = gdbval 362 363 def to_string (self): 364 result = '<edge 0x%x' % intptr(self.gdbval) 365 if intptr(self.gdbval): 366 src = bb_index_to_str(intptr(self.gdbval['src']['index'])) 367 dest = bb_index_to_str(intptr(self.gdbval['dest']['index'])) 368 result += ' (%s -> %s)' % (src, dest) 369 result += '>' 370 return result 371 372###################################################################### 373 374class Rtx: 375 def __init__(self, gdbval): 376 self.gdbval = gdbval 377 378 def GET_CODE(self): 379 return self.gdbval['code'] 380 381def GET_RTX_LENGTH(code): 382 val_rtx_length = gdb.parse_and_eval('rtx_length') 383 return intptr(val_rtx_length[code]) 384 385def GET_RTX_NAME(code): 386 val_rtx_name = gdb.parse_and_eval('rtx_name') 387 return val_rtx_name[code].string() 388 389def GET_RTX_FORMAT(code): 390 val_rtx_format = gdb.parse_and_eval('rtx_format') 391 return val_rtx_format[code].string() 392 393class RtxPrinter: 394 def __init__(self, gdbval): 395 self.gdbval = gdbval 396 self.rtx = Rtx(gdbval) 397 398 def to_string (self): 399 """ 400 For now, a cheap kludge: invoke the inferior's print 401 function to get a string to use the user, and return an empty 402 string for gdb 403 """ 404 # We use print_inline_rtx to avoid a trailing newline 405 gdb.execute('call print_inline_rtx (stderr, (const_rtx) %s, 0)' 406 % intptr(self.gdbval)) 407 return '' 408 409 # or by hand; based on gcc/print-rtl.c:print_rtx 410 result = ('<rtx_def 0x%x' 411 % (intptr(self.gdbval))) 412 code = self.rtx.GET_CODE() 413 result += ' (%s' % GET_RTX_NAME(code) 414 format_ = GET_RTX_FORMAT(code) 415 for i in range(GET_RTX_LENGTH(code)): 416 print(format_[i]) 417 result += ')>' 418 return result 419 420###################################################################### 421 422class PassPrinter: 423 def __init__(self, gdbval): 424 self.gdbval = gdbval 425 426 def to_string (self): 427 result = '<opt_pass* 0x%x' % intptr(self.gdbval) 428 if intptr(self.gdbval): 429 result += (' "%s"(%i)' 430 % (self.gdbval['name'].string(), 431 intptr(self.gdbval['static_pass_number']))) 432 result += '>' 433 return result 434 435###################################################################### 436 437class VecPrinter: 438 # -ex "up" -ex "p bb->preds" 439 def __init__(self, gdbval): 440 self.gdbval = gdbval 441 442 def display_hint (self): 443 return 'array' 444 445 def to_string (self): 446 # A trivial implementation; prettyprinting the contents is done 447 # by gdb calling the "children" method below. 448 return '0x%x' % intptr(self.gdbval) 449 450 def children (self): 451 if intptr(self.gdbval) == 0: 452 return 453 m_vecpfx = self.gdbval['m_vecpfx'] 454 m_num = m_vecpfx['m_num'] 455 m_vecdata = self.gdbval['m_vecdata'] 456 for i in range(m_num): 457 yield ('[%d]' % i, m_vecdata[i]) 458 459###################################################################### 460 461class MachineModePrinter: 462 def __init__(self, gdbval): 463 self.gdbval = gdbval 464 465 def to_string (self): 466 name = str(self.gdbval['m_mode']) 467 return name[2:] if name.startswith('E_') else name 468 469###################################################################### 470 471class OptMachineModePrinter: 472 def __init__(self, gdbval): 473 self.gdbval = gdbval 474 475 def to_string (self): 476 name = str(self.gdbval['m_mode']) 477 if name == 'E_VOIDmode': 478 return '<None>' 479 return name[2:] if name.startswith('E_') else name 480 481###################################################################### 482 483# TODO: 484# * hashtab 485# * location_t 486 487class GdbSubprinter(gdb.printing.SubPrettyPrinter): 488 def __init__(self, name, class_): 489 super(GdbSubprinter, self).__init__(name) 490 self.class_ = class_ 491 492 def handles_type(self, str_type): 493 raise NotImplementedError 494 495class GdbSubprinterTypeList(GdbSubprinter): 496 """ 497 A GdbSubprinter that handles a specific set of types 498 """ 499 def __init__(self, str_types, name, class_): 500 super(GdbSubprinterTypeList, self).__init__(name, class_) 501 self.str_types = frozenset(str_types) 502 503 def handles_type(self, str_type): 504 return str_type in self.str_types 505 506class GdbSubprinterRegex(GdbSubprinter): 507 """ 508 A GdbSubprinter that handles types that match a regex 509 """ 510 def __init__(self, regex, name, class_): 511 super(GdbSubprinterRegex, self).__init__(name, class_) 512 self.regex = re.compile(regex) 513 514 def handles_type(self, str_type): 515 return self.regex.match(str_type) 516 517class GdbPrettyPrinters(gdb.printing.PrettyPrinter): 518 def __init__(self, name): 519 super(GdbPrettyPrinters, self).__init__(name, []) 520 521 def add_printer_for_types(self, name, class_, types): 522 self.subprinters.append(GdbSubprinterTypeList(name, class_, types)) 523 524 def add_printer_for_regex(self, name, class_, regex): 525 self.subprinters.append(GdbSubprinterRegex(name, class_, regex)) 526 527 def __call__(self, gdbval): 528 type_ = gdbval.type.unqualified() 529 str_type = str(type_) 530 for printer in self.subprinters: 531 if printer.enabled and printer.handles_type(str_type): 532 return printer.class_(gdbval) 533 534 # Couldn't find a pretty printer (or it was disabled): 535 return None 536 537 538def build_pretty_printer(): 539 pp = GdbPrettyPrinters('gcc') 540 pp.add_printer_for_types(['tree'], 541 'tree', TreePrinter) 542 pp.add_printer_for_types(['cgraph_node *', 'varpool_node *', 'symtab_node *'], 543 'symtab_node', SymtabNodePrinter) 544 pp.add_printer_for_types(['cgraph_edge *'], 545 'cgraph_edge', CgraphEdgePrinter) 546 pp.add_printer_for_types(['ipa_ref *'], 547 'ipa_ref', IpaReferencePrinter) 548 pp.add_printer_for_types(['dw_die_ref'], 549 'dw_die_ref', DWDieRefPrinter) 550 pp.add_printer_for_types(['gimple', 'gimple *', 551 552 # Keep this in the same order as gimple.def: 553 'gimple_cond', 'const_gimple_cond', 554 'gimple_statement_cond *', 555 'gimple_debug', 'const_gimple_debug', 556 'gimple_statement_debug *', 557 'gimple_label', 'const_gimple_label', 558 'gimple_statement_label *', 559 'gimple_switch', 'const_gimple_switch', 560 'gimple_statement_switch *', 561 'gimple_assign', 'const_gimple_assign', 562 'gimple_statement_assign *', 563 'gimple_bind', 'const_gimple_bind', 564 'gimple_statement_bind *', 565 'gimple_phi', 'const_gimple_phi', 566 'gimple_statement_phi *'], 567 568 'gimple', 569 GimplePrinter) 570 pp.add_printer_for_types(['basic_block', 'basic_block_def *'], 571 'basic_block', 572 BasicBlockPrinter) 573 pp.add_printer_for_types(['edge', 'edge_def *'], 574 'edge', 575 CfgEdgePrinter) 576 pp.add_printer_for_types(['rtx_def *'], 'rtx_def', RtxPrinter) 577 pp.add_printer_for_types(['opt_pass *'], 'opt_pass', PassPrinter) 578 579 pp.add_printer_for_regex(r'vec<(\S+), (\S+), (\S+)> \*', 580 'vec', 581 VecPrinter) 582 583 pp.add_printer_for_regex(r'opt_mode<(\S+)>', 584 'opt_mode', OptMachineModePrinter) 585 pp.add_printer_for_types(['opt_scalar_int_mode', 586 'opt_scalar_float_mode', 587 'opt_scalar_mode'], 588 'opt_mode', OptMachineModePrinter) 589 pp.add_printer_for_regex(r'pod_mode<(\S+)>', 590 'pod_mode', MachineModePrinter) 591 pp.add_printer_for_types(['scalar_int_mode_pod', 592 'scalar_mode_pod'], 593 'pod_mode', MachineModePrinter) 594 for mode in ('scalar_mode', 'scalar_int_mode', 'scalar_float_mode', 595 'complex_mode'): 596 pp.add_printer_for_types([mode], mode, MachineModePrinter) 597 598 return pp 599 600gdb.printing.register_pretty_printer( 601 gdb.current_objfile(), 602 build_pretty_printer()) 603 604def find_gcc_source_dir(): 605 # Use location of global "g" to locate the source tree 606 sym_g = gdb.lookup_global_symbol('g') 607 path = sym_g.symtab.filename # e.g. '../../src/gcc/context.h' 608 srcdir = os.path.split(path)[0] # e.g. '../../src/gcc' 609 return srcdir 610 611class PassNames: 612 """Parse passes.def, gathering a list of pass class names""" 613 def __init__(self): 614 srcdir = find_gcc_source_dir() 615 self.names = [] 616 with open(os.path.join(srcdir, 'passes.def')) as f: 617 for line in f: 618 m = re.match('\s*NEXT_PASS \(([^,]+).*\);', line) 619 if m: 620 self.names.append(m.group(1)) 621 622class BreakOnPass(gdb.Command): 623 """ 624 A custom command for putting breakpoints on the execute hook of passes. 625 This is largely a workaround for issues with tab-completion in gdb when 626 setting breakpoints on methods on classes within anonymous namespaces. 627 628 Example of use: putting a breakpoint on "final" 629 (gdb) break-on-pass 630 Press <TAB>; it autocompletes to "pass_": 631 (gdb) break-on-pass pass_ 632 Press <TAB>: 633 Display all 219 possibilities? (y or n) 634 Press "n"; then type "f": 635 (gdb) break-on-pass pass_f 636 Press <TAB> to autocomplete to pass classnames beginning with "pass_f": 637 pass_fast_rtl_dce pass_fold_builtins 638 pass_feedback_split_functions pass_forwprop 639 pass_final pass_fre 640 pass_fixup_cfg pass_free_cfg 641 Type "in<TAB>" to complete to "pass_final": 642 (gdb) break-on-pass pass_final 643 ...and hit <RETURN>: 644 Breakpoint 6 at 0x8396ba: file ../../src/gcc/final.c, line 4526. 645 ...and we have a breakpoint set; continue execution: 646 (gdb) cont 647 Continuing. 648 Breakpoint 6, (anonymous namespace)::pass_final::execute (this=0x17fb990) at ../../src/gcc/final.c:4526 649 4526 virtual unsigned int execute (function *) { return rest_of_handle_final (); } 650 """ 651 def __init__(self): 652 gdb.Command.__init__(self, 'break-on-pass', gdb.COMMAND_BREAKPOINTS) 653 self.pass_names = None 654 655 def complete(self, text, word): 656 # Lazily load pass names: 657 if not self.pass_names: 658 self.pass_names = PassNames() 659 660 return [name 661 for name in sorted(self.pass_names.names) 662 if name.startswith(text)] 663 664 def invoke(self, arg, from_tty): 665 sym = '(anonymous namespace)::%s::execute' % arg 666 breakpoint = gdb.Breakpoint(sym) 667 668BreakOnPass() 669 670class DumpFn(gdb.Command): 671 """ 672 A custom command to dump a gimple/rtl function to file. By default, it 673 dumps the current function using 0 as dump_flags, but the function and flags 674 can also be specified. If /f <file> are passed as the first two arguments, 675 the dump is written to that file. Otherwise, a temporary file is created 676 and opened in the text editor specified in the EDITOR environment variable. 677 678 Examples of use: 679 (gdb) dump-fn 680 (gdb) dump-fn /f foo.1.txt 681 (gdb) dump-fn cfun->decl 682 (gdb) dump-fn /f foo.1.txt cfun->decl 683 (gdb) dump-fn cfun->decl 0 684 (gdb) dump-fn cfun->decl dump_flags 685 """ 686 687 def __init__(self): 688 gdb.Command.__init__(self, 'dump-fn', gdb.COMMAND_USER) 689 690 def invoke(self, arg, from_tty): 691 # Parse args, check number of args 692 args = gdb.string_to_argv(arg) 693 if len(args) >= 1 and args[0] == "/f": 694 if len(args) == 1: 695 print ("Missing file argument") 696 return 697 filename = args[1] 698 editor_mode = False 699 base_arg = 2 700 else: 701 editor = os.getenv("EDITOR", "") 702 if editor == "": 703 print ("EDITOR environment variable not defined") 704 return 705 editor_mode = True 706 base_arg = 0 707 if len(args) - base_arg > 2: 708 print ("Too many arguments") 709 return 710 711 # Set func 712 if len(args) - base_arg >= 1: 713 funcname = args[base_arg] 714 printfuncname = "function %s" % funcname 715 else: 716 funcname = "cfun ? cfun->decl : current_function_decl" 717 printfuncname = "current function" 718 func = gdb.parse_and_eval(funcname) 719 if func == 0: 720 print ("Could not find %s" % printfuncname) 721 return 722 func = "(tree)%u" % func 723 724 # Set flags 725 if len(args) - base_arg >= 2: 726 flags = gdb.parse_and_eval(args[base_arg + 1]) 727 else: 728 flags = 0 729 730 # Get tempory file, if necessary 731 if editor_mode: 732 f = tempfile.NamedTemporaryFile(delete=False, suffix=".txt") 733 filename = f.name 734 f.close() 735 736 # Open file 737 fp = gdb.parse_and_eval("fopen (\"%s\", \"w\")" % filename) 738 if fp == 0: 739 print ("Could not open file: %s" % filename) 740 return 741 fp = "(FILE *)%u" % fp 742 743 # Dump function to file 744 _ = gdb.parse_and_eval("dump_function_to_file (%s, %s, %u)" % 745 (func, fp, flags)) 746 747 # Close file 748 ret = gdb.parse_and_eval("fclose (%s)" % fp) 749 if ret != 0: 750 print ("Could not close file: %s" % filename) 751 return 752 753 # Open file in editor, if necessary 754 if editor_mode: 755 os.system("( %s \"%s\"; rm \"%s\" ) &" % 756 (editor, filename, filename)) 757 758DumpFn() 759 760class DotFn(gdb.Command): 761 """ 762 A custom command to show a gimple/rtl function control flow graph. 763 By default, it show the current function, but the function can also be 764 specified. 765 766 Examples of use: 767 (gdb) dot-fn 768 (gdb) dot-fn cfun 769 (gdb) dot-fn cfun 0 770 (gdb) dot-fn cfun dump_flags 771 """ 772 def __init__(self): 773 gdb.Command.__init__(self, 'dot-fn', gdb.COMMAND_USER) 774 775 def invoke(self, arg, from_tty): 776 # Parse args, check number of args 777 args = gdb.string_to_argv(arg) 778 if len(args) > 2: 779 print("Too many arguments") 780 return 781 782 # Set func 783 if len(args) >= 1: 784 funcname = args[0] 785 printfuncname = "function %s" % funcname 786 else: 787 funcname = "cfun" 788 printfuncname = "current function" 789 func = gdb.parse_and_eval(funcname) 790 if func == 0: 791 print("Could not find %s" % printfuncname) 792 return 793 func = "(struct function *)%s" % func 794 795 # Set flags 796 if len(args) >= 2: 797 flags = gdb.parse_and_eval(args[1]) 798 else: 799 flags = 0 800 801 # Get temp file 802 f = tempfile.NamedTemporaryFile(delete=False) 803 filename = f.name 804 805 # Close and reopen temp file to get C FILE* 806 f.close() 807 fp = gdb.parse_and_eval("fopen (\"%s\", \"w\")" % filename) 808 if fp == 0: 809 print("Cannot open temp file") 810 return 811 fp = "(FILE *)%u" % fp 812 813 # Write graph to temp file 814 _ = gdb.parse_and_eval("start_graph_dump (%s, \"<debug>\")" % fp) 815 _ = gdb.parse_and_eval("print_graph_cfg (%s, %s, %u)" 816 % (fp, func, flags)) 817 _ = gdb.parse_and_eval("end_graph_dump (%s)" % fp) 818 819 # Close temp file 820 ret = gdb.parse_and_eval("fclose (%s)" % fp) 821 if ret != 0: 822 print("Could not close temp file: %s" % filename) 823 return 824 825 # Show graph in temp file 826 os.system("( dot -Tx11 \"%s\"; rm \"%s\" ) &" % (filename, filename)) 827 828DotFn() 829 830print('Successfully loaded GDB hooks for GCC') 831