1 # Python hooks for gdb for debugging GCC 2 # Copyright (C) 2013-2022 Free Software Foundation, Inc. 3 4 # Contributed by David Malcolm <dmalcolm (at] 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') 839
Indexes created Tue Feb 24 01:34:59 UTC 2026