1 /* Perform an inferior function call, for GDB, the GNU debugger. 2 3 Copyright (C) 1986-2023 Free Software Foundation, Inc. 4 5 This file is part of GDB. 6 7 This program is free software; you can redistribute it and/or modify 8 it under the terms of the GNU General Public License as published by 9 the Free Software Foundation; either version 3 of the License, or 10 (at your option) any later version. 11 12 This program is distributed in the hope that it will be useful, 13 but WITHOUT ANY WARRANTY; without even the implied warranty of 14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 15 GNU General Public License for more details. 16 17 You should have received a copy of the GNU General Public License 18 along with this program. If not, see <http://www.gnu.org/licenses/>. */ 19 20 #include "defs.h" 21 #include "infcall.h" 22 #include "breakpoint.h" 23 #include "tracepoint.h" 24 #include "target.h" 25 #include "regcache.h" 26 #include "inferior.h" 27 #include "infrun.h" 28 #include "block.h" 29 #include "gdbcore.h" 30 #include "language.h" 31 #include "objfiles.h" 32 #include "gdbcmd.h" 33 #include "command.h" 34 #include "dummy-frame.h" 35 #include "ada-lang.h" 36 #include "f-lang.h" 37 #include "gdbthread.h" 38 #include "event-top.h" 39 #include "observable.h" 40 #include "top.h" 41 #include "interps.h" 42 #include "thread-fsm.h" 43 #include <algorithm> 44 #include "gdbsupport/scope-exit.h" 45 #include <list> 46 47 /* True if we are debugging inferior calls. */ 48 49 static bool debug_infcall = false; 50 51 /* Print an "infcall" debug statement. */ 52 53 #define infcall_debug_printf(fmt, ...) \ 54 debug_prefixed_printf_cond (debug_infcall, "infcall", fmt, ##__VA_ARGS__) 55 56 /* Print "infcall" enter/exit debug statements. */ 57 58 #define INFCALL_SCOPED_DEBUG_ENTER_EXIT \ 59 scoped_debug_enter_exit (debug_infcall, "infcall") 60 61 /* Print "infcall" start/end debug statements. */ 62 63 #define INFCALL_SCOPED_DEBUG_START_END(fmt, ...) \ 64 scoped_debug_start_end (debug_infrun, "infcall", fmt, ##__VA_ARGS__) 65 66 /* Implement 'show debug infcall'. */ 67 68 static void 69 show_debug_infcall (struct ui_file *file, int from_tty, 70 struct cmd_list_element *c, const char *value) 71 { 72 gdb_printf (file, _("Inferior call debugging is %s.\n"), value); 73 } 74 75 /* If we can't find a function's name from its address, 76 we print this instead. */ 77 #define RAW_FUNCTION_ADDRESS_FORMAT "at 0x%s" 78 #define RAW_FUNCTION_ADDRESS_SIZE (sizeof (RAW_FUNCTION_ADDRESS_FORMAT) \ 79 + 2 * sizeof (CORE_ADDR)) 80 81 /* NOTE: cagney/2003-04-16: What's the future of this code? 82 83 GDB needs an asynchronous expression evaluator, that means an 84 asynchronous inferior function call implementation, and that in 85 turn means restructuring the code so that it is event driven. */ 86 87 static bool may_call_functions_p = true; 88 static void 89 show_may_call_functions_p (struct ui_file *file, int from_tty, 90 struct cmd_list_element *c, 91 const char *value) 92 { 93 gdb_printf (file, 94 _("Permission to call functions in the program is %s.\n"), 95 value); 96 } 97 98 /* How you should pass arguments to a function depends on whether it 99 was defined in K&R style or prototype style. If you define a 100 function using the K&R syntax that takes a `float' argument, then 101 callers must pass that argument as a `double'. If you define the 102 function using the prototype syntax, then you must pass the 103 argument as a `float', with no promotion. 104 105 Unfortunately, on certain older platforms, the debug info doesn't 106 indicate reliably how each function was defined. A function type's 107 TYPE_PROTOTYPED flag may be clear, even if the function was defined 108 in prototype style. When calling a function whose TYPE_PROTOTYPED 109 flag is clear, GDB consults this flag to decide what to do. 110 111 For modern targets, it is proper to assume that, if the prototype 112 flag is clear, that can be trusted: `float' arguments should be 113 promoted to `double'. For some older targets, if the prototype 114 flag is clear, that doesn't tell us anything. The default is to 115 trust the debug information; the user can override this behavior 116 with "set coerce-float-to-double 0". */ 117 118 static bool coerce_float_to_double_p = true; 119 static void 120 show_coerce_float_to_double_p (struct ui_file *file, int from_tty, 121 struct cmd_list_element *c, const char *value) 122 { 123 gdb_printf (file, 124 _("Coercion of floats to doubles " 125 "when calling functions is %s.\n"), 126 value); 127 } 128 129 /* This boolean tells what gdb should do if a signal is received while 130 in a function called from gdb (call dummy). If set, gdb unwinds 131 the stack and restore the context to what as it was before the 132 call. 133 134 The default is to stop in the frame where the signal was received. */ 135 136 static bool unwind_on_signal_p = false; 137 static void 138 show_unwind_on_signal_p (struct ui_file *file, int from_tty, 139 struct cmd_list_element *c, const char *value) 140 { 141 gdb_printf (file, 142 _("Unwinding of stack if a signal is " 143 "received while in a call dummy is %s.\n"), 144 value); 145 } 146 147 /* This boolean tells what gdb should do if a std::terminate call is 148 made while in a function called from gdb (call dummy). 149 As the confines of a single dummy stack prohibit out-of-frame 150 handlers from handling a raised exception, and as out-of-frame 151 handlers are common in C++, this can lead to no handler being found 152 by the unwinder, and a std::terminate call. This is a false positive. 153 If set, gdb unwinds the stack and restores the context to what it 154 was before the call. 155 156 The default is to unwind the frame if a std::terminate call is 157 made. */ 158 159 static bool unwind_on_terminating_exception_p = true; 160 161 static void 162 show_unwind_on_terminating_exception_p (struct ui_file *file, int from_tty, 163 struct cmd_list_element *c, 164 const char *value) 165 166 { 167 gdb_printf (file, 168 _("Unwind stack if a C++ exception is " 169 "unhandled while in a call dummy is %s.\n"), 170 value); 171 } 172 173 /* Perform the standard coercions that are specified 174 for arguments to be passed to C, Ada or Fortran functions. 175 176 If PARAM_TYPE is non-NULL, it is the expected parameter type. 177 IS_PROTOTYPED is non-zero if the function declaration is prototyped. */ 178 179 static struct value * 180 value_arg_coerce (struct gdbarch *gdbarch, struct value *arg, 181 struct type *param_type, int is_prototyped) 182 { 183 const struct builtin_type *builtin = builtin_type (gdbarch); 184 struct type *arg_type = check_typedef (value_type (arg)); 185 struct type *type 186 = param_type ? check_typedef (param_type) : arg_type; 187 188 /* Perform any Ada- and Fortran-specific coercion first. */ 189 if (current_language->la_language == language_ada) 190 arg = ada_convert_actual (arg, type); 191 else if (current_language->la_language == language_fortran) 192 type = fortran_preserve_arg_pointer (arg, type); 193 194 /* Force the value to the target if we will need its address. At 195 this point, we could allocate arguments on the stack instead of 196 calling malloc if we knew that their addresses would not be 197 saved by the called function. */ 198 arg = value_coerce_to_target (arg); 199 200 switch (type->code ()) 201 { 202 case TYPE_CODE_REF: 203 case TYPE_CODE_RVALUE_REF: 204 { 205 struct value *new_value; 206 207 if (TYPE_IS_REFERENCE (arg_type)) 208 return value_cast_pointers (type, arg, 0); 209 210 /* Cast the value to the reference's target type, and then 211 convert it back to a reference. This will issue an error 212 if the value was not previously in memory - in some cases 213 we should clearly be allowing this, but how? */ 214 new_value = value_cast (type->target_type (), arg); 215 new_value = value_ref (new_value, type->code ()); 216 return new_value; 217 } 218 case TYPE_CODE_INT: 219 case TYPE_CODE_CHAR: 220 case TYPE_CODE_BOOL: 221 case TYPE_CODE_ENUM: 222 /* If we don't have a prototype, coerce to integer type if necessary. */ 223 if (!is_prototyped) 224 { 225 if (type->length () < builtin->builtin_int->length ()) 226 type = builtin->builtin_int; 227 } 228 /* Currently all target ABIs require at least the width of an integer 229 type for an argument. We may have to conditionalize the following 230 type coercion for future targets. */ 231 if (type->length () < builtin->builtin_int->length ()) 232 type = builtin->builtin_int; 233 break; 234 case TYPE_CODE_FLT: 235 if (!is_prototyped && coerce_float_to_double_p) 236 { 237 if (type->length () < builtin->builtin_double->length ()) 238 type = builtin->builtin_double; 239 else if (type->length () > builtin->builtin_double->length ()) 240 type = builtin->builtin_long_double; 241 } 242 break; 243 case TYPE_CODE_FUNC: 244 type = lookup_pointer_type (type); 245 break; 246 case TYPE_CODE_ARRAY: 247 /* Arrays are coerced to pointers to their first element, unless 248 they are vectors, in which case we want to leave them alone, 249 because they are passed by value. */ 250 if (current_language->c_style_arrays_p ()) 251 if (!type->is_vector ()) 252 type = lookup_pointer_type (type->target_type ()); 253 break; 254 case TYPE_CODE_UNDEF: 255 case TYPE_CODE_PTR: 256 case TYPE_CODE_STRUCT: 257 case TYPE_CODE_UNION: 258 case TYPE_CODE_VOID: 259 case TYPE_CODE_SET: 260 case TYPE_CODE_RANGE: 261 case TYPE_CODE_STRING: 262 case TYPE_CODE_ERROR: 263 case TYPE_CODE_MEMBERPTR: 264 case TYPE_CODE_METHODPTR: 265 case TYPE_CODE_METHOD: 266 case TYPE_CODE_COMPLEX: 267 default: 268 break; 269 } 270 271 return value_cast (type, arg); 272 } 273 274 /* See infcall.h. */ 275 276 CORE_ADDR 277 find_function_addr (struct value *function, 278 struct type **retval_type, 279 struct type **function_type) 280 { 281 struct type *ftype = check_typedef (value_type (function)); 282 struct gdbarch *gdbarch = ftype->arch (); 283 struct type *value_type = NULL; 284 /* Initialize it just to avoid a GCC false warning. */ 285 CORE_ADDR funaddr = 0; 286 287 /* If it's a member function, just look at the function 288 part of it. */ 289 290 /* Determine address to call. */ 291 if (ftype->code () == TYPE_CODE_FUNC 292 || ftype->code () == TYPE_CODE_METHOD) 293 funaddr = value_address (function); 294 else if (ftype->code () == TYPE_CODE_PTR) 295 { 296 funaddr = value_as_address (function); 297 ftype = check_typedef (ftype->target_type ()); 298 if (ftype->code () == TYPE_CODE_FUNC 299 || ftype->code () == TYPE_CODE_METHOD) 300 funaddr = gdbarch_convert_from_func_ptr_addr 301 (gdbarch, funaddr, current_inferior ()->top_target()); 302 } 303 if (ftype->code () == TYPE_CODE_FUNC 304 || ftype->code () == TYPE_CODE_METHOD) 305 { 306 if (ftype->is_gnu_ifunc ()) 307 { 308 CORE_ADDR resolver_addr = funaddr; 309 310 /* Resolve the ifunc. Note this may call the resolver 311 function in the inferior. */ 312 funaddr = gnu_ifunc_resolve_addr (gdbarch, resolver_addr); 313 314 /* Skip querying the function symbol if no RETVAL_TYPE or 315 FUNCTION_TYPE have been asked for. */ 316 if (retval_type != NULL || function_type != NULL) 317 { 318 type *target_ftype = find_function_type (funaddr); 319 /* If we don't have debug info for the target function, 320 see if we can instead extract the target function's 321 type from the type that the resolver returns. */ 322 if (target_ftype == NULL) 323 target_ftype = find_gnu_ifunc_target_type (resolver_addr); 324 if (target_ftype != NULL) 325 { 326 value_type = check_typedef (target_ftype)->target_type (); 327 ftype = target_ftype; 328 } 329 } 330 } 331 else 332 value_type = ftype->target_type (); 333 } 334 else if (ftype->code () == TYPE_CODE_INT) 335 { 336 /* Handle the case of functions lacking debugging info. 337 Their values are characters since their addresses are char. */ 338 if (ftype->length () == 1) 339 funaddr = value_as_address (value_addr (function)); 340 else 341 { 342 /* Handle function descriptors lacking debug info. */ 343 int found_descriptor = 0; 344 345 funaddr = 0; /* pacify "gcc -Werror" */ 346 if (VALUE_LVAL (function) == lval_memory) 347 { 348 CORE_ADDR nfunaddr; 349 350 funaddr = value_as_address (value_addr (function)); 351 nfunaddr = funaddr; 352 funaddr = gdbarch_convert_from_func_ptr_addr 353 (gdbarch, funaddr, current_inferior ()->top_target ()); 354 if (funaddr != nfunaddr) 355 found_descriptor = 1; 356 } 357 if (!found_descriptor) 358 /* Handle integer used as address of a function. */ 359 funaddr = (CORE_ADDR) value_as_long (function); 360 } 361 } 362 else 363 error (_("Invalid data type for function to be called.")); 364 365 if (retval_type != NULL) 366 *retval_type = value_type; 367 if (function_type != NULL) 368 *function_type = ftype; 369 return funaddr + gdbarch_deprecated_function_start_offset (gdbarch); 370 } 371 372 /* For CALL_DUMMY_ON_STACK, push a breakpoint sequence that the called 373 function returns to. */ 374 375 static CORE_ADDR 376 push_dummy_code (struct gdbarch *gdbarch, 377 CORE_ADDR sp, CORE_ADDR funaddr, 378 gdb::array_view<value *> args, 379 struct type *value_type, 380 CORE_ADDR *real_pc, CORE_ADDR *bp_addr, 381 struct regcache *regcache) 382 { 383 gdb_assert (gdbarch_push_dummy_code_p (gdbarch)); 384 385 return gdbarch_push_dummy_code (gdbarch, sp, funaddr, 386 args.data (), args.size (), 387 value_type, real_pc, bp_addr, 388 regcache); 389 } 390 391 /* See infcall.h. */ 392 393 void 394 error_call_unknown_return_type (const char *func_name) 395 { 396 if (func_name != NULL) 397 error (_("'%s' has unknown return type; " 398 "cast the call to its declared return type"), 399 func_name); 400 else 401 error (_("function has unknown return type; " 402 "cast the call to its declared return type")); 403 } 404 405 /* Fetch the name of the function at FUNADDR. 406 This is used in printing an error message for call_function_by_hand. 407 BUF is used to print FUNADDR in hex if the function name cannot be 408 determined. It must be large enough to hold formatted result of 409 RAW_FUNCTION_ADDRESS_FORMAT. */ 410 411 static const char * 412 get_function_name (CORE_ADDR funaddr, char *buf, int buf_size) 413 { 414 { 415 struct symbol *symbol = find_pc_function (funaddr); 416 417 if (symbol) 418 return symbol->print_name (); 419 } 420 421 { 422 /* Try the minimal symbols. */ 423 struct bound_minimal_symbol msymbol = lookup_minimal_symbol_by_pc (funaddr); 424 425 if (msymbol.minsym) 426 return msymbol.minsym->print_name (); 427 } 428 429 { 430 std::string tmp = string_printf (_(RAW_FUNCTION_ADDRESS_FORMAT), 431 hex_string (funaddr)); 432 433 gdb_assert (tmp.length () + 1 <= buf_size); 434 return strcpy (buf, tmp.c_str ()); 435 } 436 } 437 438 /* All the meta data necessary to extract the call's return value. */ 439 440 struct call_return_meta_info 441 { 442 /* The caller frame's architecture. */ 443 struct gdbarch *gdbarch; 444 445 /* The called function. */ 446 struct value *function; 447 448 /* The return value's type. */ 449 struct type *value_type; 450 451 /* Are we returning a value using a structure return or a normal 452 value return? */ 453 int struct_return_p; 454 455 /* If using a structure return, this is the structure's address. */ 456 CORE_ADDR struct_addr; 457 }; 458 459 /* Extract the called function's return value. */ 460 461 static struct value * 462 get_call_return_value (struct call_return_meta_info *ri) 463 { 464 struct value *retval = NULL; 465 thread_info *thr = inferior_thread (); 466 bool stack_temporaries = thread_stack_temporaries_enabled_p (thr); 467 468 if (ri->value_type->code () == TYPE_CODE_VOID) 469 retval = allocate_value (ri->value_type); 470 else if (ri->struct_return_p) 471 { 472 if (stack_temporaries) 473 { 474 retval = value_from_contents_and_address (ri->value_type, NULL, 475 ri->struct_addr); 476 push_thread_stack_temporary (thr, retval); 477 } 478 else 479 { 480 retval = allocate_value (ri->value_type); 481 read_value_memory (retval, 0, 1, ri->struct_addr, 482 value_contents_raw (retval).data (), 483 ri->value_type->length ()); 484 } 485 } 486 else 487 { 488 retval = allocate_value (ri->value_type); 489 gdbarch_return_value (ri->gdbarch, ri->function, ri->value_type, 490 get_current_regcache (), 491 value_contents_raw (retval).data (), NULL); 492 if (stack_temporaries && class_or_union_p (ri->value_type)) 493 { 494 /* Values of class type returned in registers are copied onto 495 the stack and their lval_type set to lval_memory. This is 496 required because further evaluation of the expression 497 could potentially invoke methods on the return value 498 requiring GDB to evaluate the "this" pointer. To evaluate 499 the this pointer, GDB needs the memory address of the 500 value. */ 501 value_force_lval (retval, ri->struct_addr); 502 push_thread_stack_temporary (thr, retval); 503 } 504 } 505 506 gdb_assert (retval != NULL); 507 return retval; 508 } 509 510 /* Data for the FSM that manages an infcall. It's main job is to 511 record the called function's return value. */ 512 513 struct call_thread_fsm : public thread_fsm 514 { 515 /* All the info necessary to be able to extract the return 516 value. */ 517 struct call_return_meta_info return_meta_info; 518 519 /* The called function's return value. This is extracted from the 520 target before the dummy frame is popped. */ 521 struct value *return_value = nullptr; 522 523 /* The top level that started the infcall (and is synchronously 524 waiting for it to end). */ 525 struct ui *waiting_ui; 526 527 call_thread_fsm (struct ui *waiting_ui, struct interp *cmd_interp, 528 struct gdbarch *gdbarch, struct value *function, 529 struct type *value_type, 530 int struct_return_p, CORE_ADDR struct_addr); 531 532 bool should_stop (struct thread_info *thread) override; 533 534 bool should_notify_stop () override; 535 }; 536 537 /* Allocate a new call_thread_fsm object. */ 538 539 call_thread_fsm::call_thread_fsm (struct ui *waiting_ui, 540 struct interp *cmd_interp, 541 struct gdbarch *gdbarch, 542 struct value *function, 543 struct type *value_type, 544 int struct_return_p, CORE_ADDR struct_addr) 545 : thread_fsm (cmd_interp), 546 waiting_ui (waiting_ui) 547 { 548 return_meta_info.gdbarch = gdbarch; 549 return_meta_info.function = function; 550 return_meta_info.value_type = value_type; 551 return_meta_info.struct_return_p = struct_return_p; 552 return_meta_info.struct_addr = struct_addr; 553 } 554 555 /* Implementation of should_stop method for infcalls. */ 556 557 bool 558 call_thread_fsm::should_stop (struct thread_info *thread) 559 { 560 INFCALL_SCOPED_DEBUG_ENTER_EXIT; 561 562 if (stop_stack_dummy == STOP_STACK_DUMMY) 563 { 564 /* Done. */ 565 set_finished (); 566 567 /* Stash the return value before the dummy frame is popped and 568 registers are restored to what they were before the 569 call.. */ 570 return_value = get_call_return_value (&return_meta_info); 571 572 /* Break out of wait_sync_command_done. */ 573 scoped_restore save_ui = make_scoped_restore (¤t_ui, waiting_ui); 574 target_terminal::ours (); 575 waiting_ui->prompt_state = PROMPT_NEEDED; 576 } 577 578 return true; 579 } 580 581 /* Implementation of should_notify_stop method for infcalls. */ 582 583 bool 584 call_thread_fsm::should_notify_stop () 585 { 586 if (finished_p ()) 587 { 588 /* Infcall succeeded. Be silent and proceed with evaluating the 589 expression. */ 590 return false; 591 } 592 593 /* Something wrong happened. E.g., an unexpected breakpoint 594 triggered, or a signal was intercepted. Notify the stop. */ 595 return true; 596 } 597 598 /* Subroutine of call_function_by_hand to simplify it. 599 Start up the inferior and wait for it to stop. 600 Return the exception if there's an error, or an exception with 601 reason >= 0 if there's no error. 602 603 This is done inside a TRY_CATCH so the caller needn't worry about 604 thrown errors. The caller should rethrow if there's an error. */ 605 606 static struct gdb_exception 607 run_inferior_call (std::unique_ptr<call_thread_fsm> sm, 608 struct thread_info *call_thread, CORE_ADDR real_pc) 609 { 610 INFCALL_SCOPED_DEBUG_ENTER_EXIT; 611 612 struct gdb_exception caught_error; 613 ptid_t call_thread_ptid = call_thread->ptid; 614 int was_running = call_thread->state == THREAD_RUNNING; 615 616 infcall_debug_printf ("call function at %s in thread %s, was_running = %d", 617 core_addr_to_string (real_pc), 618 call_thread_ptid.to_string ().c_str (), 619 was_running); 620 621 current_ui->unregister_file_handler (); 622 623 scoped_restore restore_in_infcall 624 = make_scoped_restore (&call_thread->control.in_infcall, 1); 625 626 clear_proceed_status (0); 627 628 /* Associate the FSM with the thread after clear_proceed_status 629 (otherwise it'd clear this FSM). */ 630 call_thread->set_thread_fsm (std::move (sm)); 631 632 disable_watchpoints_before_interactive_call_start (); 633 634 /* We want to print return value, please... */ 635 call_thread->control.proceed_to_finish = 1; 636 637 try 638 { 639 /* Infcalls run synchronously, in the foreground. */ 640 scoped_restore restore_prompt_state 641 = make_scoped_restore (¤t_ui->prompt_state, PROMPT_BLOCKED); 642 643 /* So that we don't print the prompt prematurely in 644 fetch_inferior_event. */ 645 scoped_restore restore_ui_async 646 = make_scoped_restore (¤t_ui->async, 0); 647 648 proceed (real_pc, GDB_SIGNAL_0); 649 650 infrun_debug_show_threads ("non-exited threads after proceed for inferior-call", 651 all_non_exited_threads ()); 652 653 /* Inferior function calls are always synchronous, even if the 654 target supports asynchronous execution. */ 655 wait_sync_command_done (); 656 657 infcall_debug_printf ("inferior call completed successfully"); 658 } 659 catch (gdb_exception &e) 660 { 661 infcall_debug_printf ("exception while making inferior call (%d): %s", 662 e.reason, e.what ()); 663 caught_error = std::move (e); 664 } 665 666 infcall_debug_printf ("thread is now: %s", 667 inferior_ptid.to_string ().c_str ()); 668 669 /* If GDB has the prompt blocked before, then ensure that it remains 670 so. normal_stop calls async_enable_stdin, so reset the prompt 671 state again here. In other cases, stdin will be re-enabled by 672 inferior_event_handler, when an exception is thrown. */ 673 if (current_ui->prompt_state == PROMPT_BLOCKED) 674 current_ui->unregister_file_handler (); 675 else 676 current_ui->register_file_handler (); 677 678 /* If the infcall does NOT succeed, normal_stop will have already 679 finished the thread states. However, on success, normal_stop 680 defers here, so that we can set back the thread states to what 681 they were before the call. Note that we must also finish the 682 state of new threads that might have spawned while the call was 683 running. The main cases to handle are: 684 685 - "(gdb) print foo ()", or any other command that evaluates an 686 expression at the prompt. (The thread was marked stopped before.) 687 688 - "(gdb) break foo if return_false()" or similar cases where we 689 do an infcall while handling an event (while the thread is still 690 marked running). In this example, whether the condition 691 evaluates true and thus we'll present a user-visible stop is 692 decided elsewhere. */ 693 if (!was_running 694 && call_thread_ptid == inferior_ptid 695 && stop_stack_dummy == STOP_STACK_DUMMY) 696 finish_thread_state (call_thread->inf->process_target (), 697 user_visible_resume_ptid (0)); 698 699 enable_watchpoints_after_interactive_call_stop (); 700 701 /* Call breakpoint_auto_delete on the current contents of the bpstat 702 of inferior call thread. 703 If all error()s out of proceed ended up calling normal_stop 704 (and perhaps they should; it already does in the special case 705 of error out of resume()), then we wouldn't need this. */ 706 if (caught_error.reason < 0) 707 { 708 if (call_thread->state != THREAD_EXITED) 709 breakpoint_auto_delete (call_thread->control.stop_bpstat); 710 } 711 712 return caught_error; 713 } 714 715 /* Reserve space on the stack for a value of the given type. 716 Return the address of the allocated space. 717 Make certain that the value is correctly aligned. 718 The SP argument is modified. */ 719 720 static CORE_ADDR 721 reserve_stack_space (const type *values_type, CORE_ADDR &sp) 722 { 723 frame_info_ptr frame = get_current_frame (); 724 struct gdbarch *gdbarch = get_frame_arch (frame); 725 CORE_ADDR addr = 0; 726 727 if (gdbarch_inner_than (gdbarch, 1, 2)) 728 { 729 /* Stack grows downward. Align STRUCT_ADDR and SP after 730 making space. */ 731 sp -= values_type->length (); 732 if (gdbarch_frame_align_p (gdbarch)) 733 sp = gdbarch_frame_align (gdbarch, sp); 734 addr = sp; 735 } 736 else 737 { 738 /* Stack grows upward. Align the frame, allocate space, and 739 then again, re-align the frame??? */ 740 if (gdbarch_frame_align_p (gdbarch)) 741 sp = gdbarch_frame_align (gdbarch, sp); 742 addr = sp; 743 sp += values_type->length (); 744 if (gdbarch_frame_align_p (gdbarch)) 745 sp = gdbarch_frame_align (gdbarch, sp); 746 } 747 748 return addr; 749 } 750 751 /* The data structure which keeps a destructor function and 752 its implicit 'this' parameter. */ 753 754 struct destructor_info 755 { 756 destructor_info (struct value *function, struct value *self) 757 : function (function), self (self) { } 758 759 struct value *function; 760 struct value *self; 761 }; 762 763 764 /* Auxiliary function that takes a list of destructor functions 765 with their 'this' parameters, and invokes the functions. */ 766 767 static void 768 call_destructors (const std::list<destructor_info> &dtors_to_invoke, 769 struct type *default_return_type) 770 { 771 for (auto vals : dtors_to_invoke) 772 { 773 call_function_by_hand (vals.function, default_return_type, 774 gdb::make_array_view (&(vals.self), 1)); 775 } 776 } 777 778 /* See infcall.h. */ 779 780 struct value * 781 call_function_by_hand (struct value *function, 782 type *default_return_type, 783 gdb::array_view<value *> args) 784 { 785 return call_function_by_hand_dummy (function, default_return_type, 786 args, NULL, NULL); 787 } 788 789 /* All this stuff with a dummy frame may seem unnecessarily complicated 790 (why not just save registers in GDB?). The purpose of pushing a dummy 791 frame which looks just like a real frame is so that if you call a 792 function and then hit a breakpoint (get a signal, etc), "backtrace" 793 will look right. Whether the backtrace needs to actually show the 794 stack at the time the inferior function was called is debatable, but 795 it certainly needs to not display garbage. So if you are contemplating 796 making dummy frames be different from normal frames, consider that. */ 797 798 /* Perform a function call in the inferior. 799 ARGS is a vector of values of arguments. 800 FUNCTION is a value, the function to be called. 801 Returns a value representing what the function returned. 802 May fail to return, if a breakpoint or signal is hit 803 during the execution of the function. 804 805 ARGS is modified to contain coerced values. */ 806 807 struct value * 808 call_function_by_hand_dummy (struct value *function, 809 type *default_return_type, 810 gdb::array_view<value *> args, 811 dummy_frame_dtor_ftype *dummy_dtor, 812 void *dummy_dtor_data) 813 { 814 INFCALL_SCOPED_DEBUG_ENTER_EXIT; 815 816 CORE_ADDR sp; 817 struct type *target_values_type; 818 function_call_return_method return_method = return_method_normal; 819 CORE_ADDR struct_addr = 0; 820 CORE_ADDR real_pc; 821 CORE_ADDR bp_addr; 822 struct frame_id dummy_id; 823 frame_info_ptr frame; 824 struct gdbarch *gdbarch; 825 ptid_t call_thread_ptid; 826 struct gdb_exception e; 827 char name_buf[RAW_FUNCTION_ADDRESS_SIZE]; 828 829 if (!may_call_functions_p) 830 error (_("Cannot call functions in the program: " 831 "may-call-functions is off.")); 832 833 if (!target_has_execution ()) 834 noprocess (); 835 836 if (get_traceframe_number () >= 0) 837 error (_("May not call functions while looking at trace frames.")); 838 839 if (execution_direction == EXEC_REVERSE) 840 error (_("Cannot call functions in reverse mode.")); 841 842 /* We're going to run the target, and inspect the thread's state 843 afterwards. Hold a strong reference so that the pointer remains 844 valid even if the thread exits. */ 845 thread_info_ref call_thread 846 = thread_info_ref::new_reference (inferior_thread ()); 847 848 bool stack_temporaries = thread_stack_temporaries_enabled_p (call_thread.get ()); 849 850 frame = get_current_frame (); 851 frame.prepare_reinflate (); 852 gdbarch = get_frame_arch (frame); 853 854 if (!gdbarch_push_dummy_call_p (gdbarch)) 855 error (_("This target does not support function calls.")); 856 857 /* Find the function type and do a sanity check. */ 858 type *ftype; 859 type *values_type; 860 CORE_ADDR funaddr = find_function_addr (function, &values_type, &ftype); 861 862 if (is_nocall_function (ftype)) 863 error (_("Cannot call the function '%s' which does not follow the " 864 "target calling convention."), 865 get_function_name (funaddr, name_buf, sizeof (name_buf))); 866 867 frame.reinflate (); 868 869 if (values_type == NULL || values_type->is_stub ()) 870 values_type = default_return_type; 871 if (values_type == NULL) 872 { 873 const char *name = get_function_name (funaddr, 874 name_buf, sizeof (name_buf)); 875 error (_("'%s' has unknown return type; " 876 "cast the call to its declared return type"), 877 name); 878 } 879 880 values_type = check_typedef (values_type); 881 882 if (args.size () < ftype->num_fields ()) 883 error (_("Too few arguments in function call.")); 884 885 infcall_debug_printf ("calling %s", get_function_name (funaddr, name_buf, 886 sizeof (name_buf))); 887 888 /* A holder for the inferior status. 889 This is only needed while we're preparing the inferior function call. */ 890 infcall_control_state_up inf_status (save_infcall_control_state ()); 891 892 /* Save the caller's registers and other state associated with the 893 inferior itself so that they can be restored once the 894 callee returns. To allow nested calls the registers are (further 895 down) pushed onto a dummy frame stack. This unique pointer 896 is released once the regcache has been pushed). */ 897 infcall_suspend_state_up caller_state (save_infcall_suspend_state ()); 898 899 /* Ensure that the initial SP is correctly aligned. */ 900 { 901 CORE_ADDR old_sp = get_frame_sp (frame); 902 903 if (gdbarch_frame_align_p (gdbarch)) 904 { 905 sp = gdbarch_frame_align (gdbarch, old_sp); 906 /* NOTE: cagney/2003-08-13: Skip the "red zone". For some 907 ABIs, a function can use memory beyond the inner most stack 908 address. AMD64 called that region the "red zone". Skip at 909 least the "red zone" size before allocating any space on 910 the stack. */ 911 if (gdbarch_inner_than (gdbarch, 1, 2)) 912 sp -= gdbarch_frame_red_zone_size (gdbarch); 913 else 914 sp += gdbarch_frame_red_zone_size (gdbarch); 915 /* Still aligned? */ 916 gdb_assert (sp == gdbarch_frame_align (gdbarch, sp)); 917 /* NOTE: cagney/2002-09-18: 918 919 On a RISC architecture, a void parameterless generic dummy 920 frame (i.e., no parameters, no result) typically does not 921 need to push anything the stack and hence can leave SP and 922 FP. Similarly, a frameless (possibly leaf) function does 923 not push anything on the stack and, hence, that too can 924 leave FP and SP unchanged. As a consequence, a sequence of 925 void parameterless generic dummy frame calls to frameless 926 functions will create a sequence of effectively identical 927 frames (SP, FP and TOS and PC the same). This, not 928 surprisingly, results in what appears to be a stack in an 929 infinite loop --- when GDB tries to find a generic dummy 930 frame on the internal dummy frame stack, it will always 931 find the first one. 932 933 To avoid this problem, the code below always grows the 934 stack. That way, two dummy frames can never be identical. 935 It does burn a few bytes of stack but that is a small price 936 to pay :-). */ 937 if (sp == old_sp) 938 { 939 if (gdbarch_inner_than (gdbarch, 1, 2)) 940 /* Stack grows down. */ 941 sp = gdbarch_frame_align (gdbarch, old_sp - 1); 942 else 943 /* Stack grows up. */ 944 sp = gdbarch_frame_align (gdbarch, old_sp + 1); 945 } 946 /* SP may have underflown address zero here from OLD_SP. Memory access 947 functions will probably fail in such case but that is a target's 948 problem. */ 949 } 950 else 951 /* FIXME: cagney/2002-09-18: Hey, you loose! 952 953 Who knows how badly aligned the SP is! 954 955 If the generic dummy frame ends up empty (because nothing is 956 pushed) GDB won't be able to correctly perform back traces. 957 If a target is having trouble with backtraces, first thing to 958 do is add FRAME_ALIGN() to the architecture vector. If that 959 fails, try dummy_id(). 960 961 If the ABI specifies a "Red Zone" (see the doco) the code 962 below will quietly trash it. */ 963 sp = old_sp; 964 965 /* Skip over the stack temporaries that might have been generated during 966 the evaluation of an expression. */ 967 if (stack_temporaries) 968 { 969 struct value *lastval; 970 971 lastval = get_last_thread_stack_temporary (call_thread.get ()); 972 if (lastval != NULL) 973 { 974 CORE_ADDR lastval_addr = value_address (lastval); 975 976 if (gdbarch_inner_than (gdbarch, 1, 2)) 977 { 978 gdb_assert (sp >= lastval_addr); 979 sp = lastval_addr; 980 } 981 else 982 { 983 gdb_assert (sp <= lastval_addr); 984 sp = lastval_addr + value_type (lastval)->length (); 985 } 986 987 if (gdbarch_frame_align_p (gdbarch)) 988 sp = gdbarch_frame_align (gdbarch, sp); 989 } 990 } 991 } 992 993 /* Are we returning a value using a structure return? */ 994 995 if (gdbarch_return_in_first_hidden_param_p (gdbarch, values_type)) 996 { 997 return_method = return_method_hidden_param; 998 999 /* Tell the target specific argument pushing routine not to 1000 expect a value. */ 1001 target_values_type = builtin_type (gdbarch)->builtin_void; 1002 } 1003 else 1004 { 1005 if (using_struct_return (gdbarch, function, values_type)) 1006 return_method = return_method_struct; 1007 target_values_type = values_type; 1008 } 1009 1010 gdb::observers::inferior_call_pre.notify (inferior_ptid, funaddr); 1011 1012 /* Determine the location of the breakpoint (and possibly other 1013 stuff) that the called function will return to. The SPARC, for a 1014 function returning a structure or union, needs to make space for 1015 not just the breakpoint but also an extra word containing the 1016 size (?) of the structure being passed. */ 1017 1018 switch (gdbarch_call_dummy_location (gdbarch)) 1019 { 1020 case ON_STACK: 1021 { 1022 const gdb_byte *bp_bytes; 1023 CORE_ADDR bp_addr_as_address; 1024 int bp_size; 1025 1026 /* Be careful BP_ADDR is in inferior PC encoding while 1027 BP_ADDR_AS_ADDRESS is a plain memory address. */ 1028 1029 sp = push_dummy_code (gdbarch, sp, funaddr, args, 1030 target_values_type, &real_pc, &bp_addr, 1031 get_current_regcache ()); 1032 1033 /* Write a legitimate instruction at the point where the infcall 1034 breakpoint is going to be inserted. While this instruction 1035 is never going to be executed, a user investigating the 1036 memory from GDB would see this instruction instead of random 1037 uninitialized bytes. We chose the breakpoint instruction 1038 as it may look as the most logical one to the user and also 1039 valgrind 3.7.0 needs it for proper vgdb inferior calls. 1040 1041 If software breakpoints are unsupported for this target we 1042 leave the user visible memory content uninitialized. */ 1043 1044 bp_addr_as_address = bp_addr; 1045 bp_bytes = gdbarch_breakpoint_from_pc (gdbarch, &bp_addr_as_address, 1046 &bp_size); 1047 if (bp_bytes != NULL) 1048 write_memory (bp_addr_as_address, bp_bytes, bp_size); 1049 } 1050 break; 1051 case AT_ENTRY_POINT: 1052 { 1053 CORE_ADDR dummy_addr; 1054 1055 real_pc = funaddr; 1056 dummy_addr = entry_point_address (); 1057 1058 /* A call dummy always consists of just a single breakpoint, so 1059 its address is the same as the address of the dummy. 1060 1061 The actual breakpoint is inserted separatly so there is no need to 1062 write that out. */ 1063 bp_addr = dummy_addr; 1064 break; 1065 } 1066 default: 1067 internal_error (_("bad switch")); 1068 } 1069 1070 /* Coerce the arguments and handle pass-by-reference. 1071 We want to remember the destruction required for pass-by-ref values. 1072 For these, store the dtor function and the 'this' argument 1073 in DTORS_TO_INVOKE. */ 1074 std::list<destructor_info> dtors_to_invoke; 1075 1076 for (int i = args.size () - 1; i >= 0; i--) 1077 { 1078 int prototyped; 1079 struct type *param_type; 1080 1081 /* FIXME drow/2002-05-31: Should just always mark methods as 1082 prototyped. Can we respect TYPE_VARARGS? Probably not. */ 1083 if (ftype->code () == TYPE_CODE_METHOD) 1084 prototyped = 1; 1085 else if (ftype->target_type () == NULL && ftype->num_fields () == 0 1086 && default_return_type != NULL) 1087 { 1088 /* Calling a no-debug function with the return type 1089 explicitly cast. Assume the function is prototyped, 1090 with a prototype matching the types of the arguments. 1091 E.g., with: 1092 float mult (float v1, float v2) { return v1 * v2; } 1093 This: 1094 (gdb) p (float) mult (2.0f, 3.0f) 1095 Is a simpler alternative to: 1096 (gdb) p ((float (*) (float, float)) mult) (2.0f, 3.0f) 1097 */ 1098 prototyped = 1; 1099 } 1100 else if (i < ftype->num_fields ()) 1101 prototyped = ftype->is_prototyped (); 1102 else 1103 prototyped = 0; 1104 1105 if (i < ftype->num_fields ()) 1106 param_type = ftype->field (i).type (); 1107 else 1108 param_type = NULL; 1109 1110 value *original_arg = args[i]; 1111 args[i] = value_arg_coerce (gdbarch, args[i], 1112 param_type, prototyped); 1113 1114 if (param_type == NULL) 1115 continue; 1116 1117 auto info = language_pass_by_reference (param_type); 1118 if (!info.copy_constructible) 1119 error (_("expression cannot be evaluated because the type '%s' " 1120 "is not copy constructible"), param_type->name ()); 1121 1122 if (!info.destructible) 1123 error (_("expression cannot be evaluated because the type '%s' " 1124 "is not destructible"), param_type->name ()); 1125 1126 if (info.trivially_copyable) 1127 continue; 1128 1129 /* Make a copy of the argument on the stack. If the argument is 1130 trivially copy ctor'able, copy bit by bit. Otherwise, call 1131 the copy ctor to initialize the clone. */ 1132 CORE_ADDR addr = reserve_stack_space (param_type, sp); 1133 value *clone 1134 = value_from_contents_and_address (param_type, nullptr, addr); 1135 push_thread_stack_temporary (call_thread.get (), clone); 1136 value *clone_ptr 1137 = value_from_pointer (lookup_pointer_type (param_type), addr); 1138 1139 if (info.trivially_copy_constructible) 1140 { 1141 int length = param_type->length (); 1142 write_memory (addr, value_contents (args[i]).data (), length); 1143 } 1144 else 1145 { 1146 value *copy_ctor; 1147 value *cctor_args[2] = { clone_ptr, original_arg }; 1148 find_overload_match (gdb::make_array_view (cctor_args, 2), 1149 param_type->name (), METHOD, 1150 &clone_ptr, nullptr, ©_ctor, nullptr, 1151 nullptr, 0, EVAL_NORMAL); 1152 1153 if (copy_ctor == nullptr) 1154 error (_("expression cannot be evaluated because a copy " 1155 "constructor for the type '%s' could not be found " 1156 "(maybe inlined?)"), param_type->name ()); 1157 1158 call_function_by_hand (copy_ctor, default_return_type, 1159 gdb::make_array_view (cctor_args, 2)); 1160 } 1161 1162 /* If the argument has a destructor, remember it so that we 1163 invoke it after the infcall is complete. */ 1164 if (!info.trivially_destructible) 1165 { 1166 /* Looking up the function via overload resolution does not 1167 work because the compiler (in particular, gcc) adds an 1168 artificial int parameter in some cases. So we look up 1169 the function by using the "~" name. This should be OK 1170 because there can be only one dtor definition. */ 1171 const char *dtor_name = nullptr; 1172 for (int fieldnum = 0; 1173 fieldnum < TYPE_NFN_FIELDS (param_type); 1174 fieldnum++) 1175 { 1176 fn_field *fn 1177 = TYPE_FN_FIELDLIST1 (param_type, fieldnum); 1178 const char *field_name 1179 = TYPE_FN_FIELDLIST_NAME (param_type, fieldnum); 1180 1181 if (field_name[0] == '~') 1182 dtor_name = TYPE_FN_FIELD_PHYSNAME (fn, 0); 1183 } 1184 1185 if (dtor_name == nullptr) 1186 error (_("expression cannot be evaluated because a destructor " 1187 "for the type '%s' could not be found " 1188 "(maybe inlined?)"), param_type->name ()); 1189 1190 value *dtor 1191 = find_function_in_inferior (dtor_name, 0); 1192 1193 /* Insert the dtor to the front of the list to call them 1194 in reverse order later. */ 1195 dtors_to_invoke.emplace_front (dtor, clone_ptr); 1196 } 1197 1198 args[i] = clone_ptr; 1199 } 1200 1201 /* Reserve space for the return structure to be written on the 1202 stack, if necessary. 1203 1204 While evaluating expressions, we reserve space on the stack for 1205 return values of class type even if the language ABI and the target 1206 ABI do not require that the return value be passed as a hidden first 1207 argument. This is because we want to store the return value as an 1208 on-stack temporary while the expression is being evaluated. This 1209 enables us to have chained function calls in expressions. 1210 1211 Keeping the return values as on-stack temporaries while the expression 1212 is being evaluated is OK because the thread is stopped until the 1213 expression is completely evaluated. */ 1214 1215 if (return_method != return_method_normal 1216 || (stack_temporaries && class_or_union_p (values_type))) 1217 struct_addr = reserve_stack_space (values_type, sp); 1218 1219 std::vector<struct value *> new_args; 1220 if (return_method == return_method_hidden_param) 1221 { 1222 /* Add the new argument to the front of the argument list. */ 1223 new_args.reserve (args.size ()); 1224 new_args.push_back 1225 (value_from_pointer (lookup_pointer_type (values_type), struct_addr)); 1226 new_args.insert (new_args.end (), args.begin (), args.end ()); 1227 args = new_args; 1228 } 1229 1230 /* Create the dummy stack frame. Pass in the call dummy address as, 1231 presumably, the ABI code knows where, in the call dummy, the 1232 return address should be pointed. */ 1233 sp = gdbarch_push_dummy_call (gdbarch, function, get_current_regcache (), 1234 bp_addr, args.size (), args.data (), 1235 sp, return_method, struct_addr); 1236 1237 /* Set up a frame ID for the dummy frame so we can pass it to 1238 set_momentary_breakpoint. We need to give the breakpoint a frame 1239 ID so that the breakpoint code can correctly re-identify the 1240 dummy breakpoint. */ 1241 /* Sanity. The exact same SP value is returned by PUSH_DUMMY_CALL, 1242 saved as the dummy-frame TOS, and used by dummy_id to form 1243 the frame ID's stack address. */ 1244 dummy_id = frame_id_build (sp, bp_addr); 1245 1246 /* Create a momentary breakpoint at the return address of the 1247 inferior. That way it breaks when it returns. */ 1248 1249 { 1250 symtab_and_line sal; 1251 sal.pspace = current_program_space; 1252 sal.pc = bp_addr; 1253 sal.section = find_pc_overlay (sal.pc); 1254 1255 /* Sanity. The exact same SP value is returned by 1256 PUSH_DUMMY_CALL, saved as the dummy-frame TOS, and used by 1257 dummy_id to form the frame ID's stack address. */ 1258 breakpoint *bpt 1259 = set_momentary_breakpoint (gdbarch, sal, 1260 dummy_id, bp_call_dummy).release (); 1261 1262 /* set_momentary_breakpoint invalidates FRAME. */ 1263 frame = NULL; 1264 1265 bpt->disposition = disp_del; 1266 gdb_assert (bpt->related_breakpoint == bpt); 1267 1268 breakpoint *longjmp_b = set_longjmp_breakpoint_for_call_dummy (); 1269 if (longjmp_b) 1270 { 1271 /* Link BPT into the chain of LONGJMP_B. */ 1272 bpt->related_breakpoint = longjmp_b; 1273 while (longjmp_b->related_breakpoint != bpt->related_breakpoint) 1274 longjmp_b = longjmp_b->related_breakpoint; 1275 longjmp_b->related_breakpoint = bpt; 1276 } 1277 } 1278 1279 /* Create a breakpoint in std::terminate. 1280 If a C++ exception is raised in the dummy-frame, and the 1281 exception handler is (normally, and expected to be) out-of-frame, 1282 the default C++ handler will (wrongly) be called in an inferior 1283 function call. This is wrong, as an exception can be normally 1284 and legally handled out-of-frame. The confines of the dummy frame 1285 prevent the unwinder from finding the correct handler (or any 1286 handler, unless it is in-frame). The default handler calls 1287 std::terminate. This will kill the inferior. Assert that 1288 terminate should never be called in an inferior function 1289 call. Place a momentary breakpoint in the std::terminate function 1290 and if triggered in the call, rewind. */ 1291 if (unwind_on_terminating_exception_p) 1292 set_std_terminate_breakpoint (); 1293 1294 /* Everything's ready, push all the info needed to restore the 1295 caller (and identify the dummy-frame) onto the dummy-frame 1296 stack. */ 1297 dummy_frame_push (caller_state.release (), &dummy_id, call_thread.get ()); 1298 if (dummy_dtor != NULL) 1299 register_dummy_frame_dtor (dummy_id, call_thread.get (), 1300 dummy_dtor, dummy_dtor_data); 1301 1302 /* Register a clean-up for unwind_on_terminating_exception_breakpoint. */ 1303 SCOPE_EXIT { delete_std_terminate_breakpoint (); }; 1304 1305 /* - SNIP - SNIP - SNIP - SNIP - SNIP - SNIP - SNIP - SNIP - SNIP - 1306 If you're looking to implement asynchronous dummy-frames, then 1307 just below is the place to chop this function in two.. */ 1308 1309 { 1310 /* Save the current FSM. We'll override it. */ 1311 std::unique_ptr<thread_fsm> saved_sm = call_thread->release_thread_fsm (); 1312 struct call_thread_fsm *sm; 1313 1314 /* Save this thread's ptid, we need it later but the thread 1315 may have exited. */ 1316 call_thread_ptid = call_thread->ptid; 1317 1318 /* Run the inferior until it stops. */ 1319 1320 /* Create the FSM used to manage the infcall. It tells infrun to 1321 not report the stop to the user, and captures the return value 1322 before the dummy frame is popped. run_inferior_call registers 1323 it with the thread ASAP. */ 1324 sm = new call_thread_fsm (current_ui, command_interp (), 1325 gdbarch, function, 1326 values_type, 1327 return_method != return_method_normal, 1328 struct_addr); 1329 { 1330 std::unique_ptr<call_thread_fsm> sm_up (sm); 1331 e = run_inferior_call (std::move (sm_up), call_thread.get (), real_pc); 1332 } 1333 1334 if (e.reason < 0) 1335 infcall_debug_printf ("after inferior call, exception (%d): %s", 1336 e.reason, e.what ()); 1337 infcall_debug_printf ("after inferior call, thread state is: %s", 1338 thread_state_string (call_thread->state)); 1339 1340 gdb::observers::inferior_call_post.notify (call_thread_ptid, funaddr); 1341 1342 if (call_thread->state != THREAD_EXITED) 1343 { 1344 /* The FSM should still be the same. */ 1345 gdb_assert (call_thread->thread_fsm () == sm); 1346 1347 if (call_thread->thread_fsm ()->finished_p ()) 1348 { 1349 struct value *retval; 1350 1351 infcall_debug_printf ("call completed"); 1352 1353 /* The inferior call is successful. Pop the dummy frame, 1354 which runs its destructors and restores the inferior's 1355 suspend state, and restore the inferior control 1356 state. */ 1357 dummy_frame_pop (dummy_id, call_thread.get ()); 1358 restore_infcall_control_state (inf_status.release ()); 1359 1360 /* Get the return value. */ 1361 retval = sm->return_value; 1362 1363 /* Restore the original FSM and clean up / destroh the call FSM. 1364 Doing it in this order ensures that if the call to clean_up 1365 throws, the original FSM is properly restored. */ 1366 { 1367 std::unique_ptr<thread_fsm> finalizing 1368 = call_thread->release_thread_fsm (); 1369 call_thread->set_thread_fsm (std::move (saved_sm)); 1370 1371 finalizing->clean_up (call_thread.get ()); 1372 } 1373 1374 maybe_remove_breakpoints (); 1375 1376 gdb_assert (retval != NULL); 1377 1378 /* Destruct the pass-by-ref argument clones. */ 1379 call_destructors (dtors_to_invoke, default_return_type); 1380 1381 return retval; 1382 } 1383 else 1384 infcall_debug_printf ("call did not complete"); 1385 1386 /* Didn't complete. Clean up / destroy the call FSM, and restore the 1387 previous state machine, and handle the error. */ 1388 { 1389 std::unique_ptr<thread_fsm> finalizing 1390 = call_thread->release_thread_fsm (); 1391 call_thread->set_thread_fsm (std::move (saved_sm)); 1392 1393 finalizing->clean_up (call_thread.get ()); 1394 } 1395 } 1396 } 1397 1398 /* Rethrow an error if we got one trying to run the inferior. */ 1399 1400 if (e.reason < 0) 1401 { 1402 const char *name = get_function_name (funaddr, 1403 name_buf, sizeof (name_buf)); 1404 1405 discard_infcall_control_state (inf_status.release ()); 1406 1407 /* We could discard the dummy frame here if the program exited, 1408 but it will get garbage collected the next time the program is 1409 run anyway. */ 1410 1411 switch (e.reason) 1412 { 1413 case RETURN_ERROR: 1414 throw_error (e.error, _("%s\n\ 1415 An error occurred while in a function called from GDB.\n\ 1416 Evaluation of the expression containing the function\n\ 1417 (%s) will be abandoned.\n\ 1418 When the function is done executing, GDB will silently stop."), 1419 e.what (), name); 1420 case RETURN_QUIT: 1421 default: 1422 throw_exception (std::move (e)); 1423 } 1424 } 1425 1426 /* If the program has exited, or we stopped at a different thread, 1427 exit and inform the user. */ 1428 1429 if (! target_has_execution ()) 1430 { 1431 const char *name = get_function_name (funaddr, 1432 name_buf, sizeof (name_buf)); 1433 1434 /* If we try to restore the inferior status, 1435 we'll crash as the inferior is no longer running. */ 1436 discard_infcall_control_state (inf_status.release ()); 1437 1438 /* We could discard the dummy frame here given that the program exited, 1439 but it will get garbage collected the next time the program is 1440 run anyway. */ 1441 1442 error (_("The program being debugged exited while in a function " 1443 "called from GDB.\n" 1444 "Evaluation of the expression containing the function\n" 1445 "(%s) will be abandoned."), 1446 name); 1447 } 1448 1449 if (call_thread_ptid != inferior_ptid) 1450 { 1451 const char *name = get_function_name (funaddr, 1452 name_buf, sizeof (name_buf)); 1453 1454 /* We've switched threads. This can happen if another thread gets a 1455 signal or breakpoint while our thread was running. 1456 There's no point in restoring the inferior status, 1457 we're in a different thread. */ 1458 discard_infcall_control_state (inf_status.release ()); 1459 /* Keep the dummy frame record, if the user switches back to the 1460 thread with the hand-call, we'll need it. */ 1461 if (stopped_by_random_signal) 1462 error (_("\ 1463 The program received a signal in another thread while\n\ 1464 making a function call from GDB.\n\ 1465 Evaluation of the expression containing the function\n\ 1466 (%s) will be abandoned.\n\ 1467 When the function is done executing, GDB will silently stop."), 1468 name); 1469 else 1470 error (_("\ 1471 The program stopped in another thread while making a function call from GDB.\n\ 1472 Evaluation of the expression containing the function\n\ 1473 (%s) will be abandoned.\n\ 1474 When the function is done executing, GDB will silently stop."), 1475 name); 1476 } 1477 1478 { 1479 /* Make a copy as NAME may be in an objfile freed by dummy_frame_pop. */ 1480 std::string name = get_function_name (funaddr, name_buf, 1481 sizeof (name_buf)); 1482 1483 if (stopped_by_random_signal) 1484 { 1485 /* We stopped inside the FUNCTION because of a random 1486 signal. Further execution of the FUNCTION is not 1487 allowed. */ 1488 1489 if (unwind_on_signal_p) 1490 { 1491 /* The user wants the context restored. */ 1492 1493 /* We must get back to the frame we were before the 1494 dummy call. */ 1495 dummy_frame_pop (dummy_id, call_thread.get ()); 1496 1497 /* We also need to restore inferior status to that before the 1498 dummy call. */ 1499 restore_infcall_control_state (inf_status.release ()); 1500 1501 /* FIXME: Insert a bunch of wrap_here; name can be very 1502 long if it's a C++ name with arguments and stuff. */ 1503 error (_("\ 1504 The program being debugged was signaled while in a function called from GDB.\n\ 1505 GDB has restored the context to what it was before the call.\n\ 1506 To change this behavior use \"set unwindonsignal off\".\n\ 1507 Evaluation of the expression containing the function\n\ 1508 (%s) will be abandoned."), 1509 name.c_str ()); 1510 } 1511 else 1512 { 1513 /* The user wants to stay in the frame where we stopped 1514 (default). 1515 Discard inferior status, we're not at the same point 1516 we started at. */ 1517 discard_infcall_control_state (inf_status.release ()); 1518 1519 /* FIXME: Insert a bunch of wrap_here; name can be very 1520 long if it's a C++ name with arguments and stuff. */ 1521 error (_("\ 1522 The program being debugged was signaled while in a function called from GDB.\n\ 1523 GDB remains in the frame where the signal was received.\n\ 1524 To change this behavior use \"set unwindonsignal on\".\n\ 1525 Evaluation of the expression containing the function\n\ 1526 (%s) will be abandoned.\n\ 1527 When the function is done executing, GDB will silently stop."), 1528 name.c_str ()); 1529 } 1530 } 1531 1532 if (stop_stack_dummy == STOP_STD_TERMINATE) 1533 { 1534 /* We must get back to the frame we were before the dummy 1535 call. */ 1536 dummy_frame_pop (dummy_id, call_thread.get ()); 1537 1538 /* We also need to restore inferior status to that before 1539 the dummy call. */ 1540 restore_infcall_control_state (inf_status.release ()); 1541 1542 error (_("\ 1543 The program being debugged entered a std::terminate call, most likely\n\ 1544 caused by an unhandled C++ exception. GDB blocked this call in order\n\ 1545 to prevent the program from being terminated, and has restored the\n\ 1546 context to its original state before the call.\n\ 1547 To change this behaviour use \"set unwind-on-terminating-exception off\".\n\ 1548 Evaluation of the expression containing the function (%s)\n\ 1549 will be abandoned."), 1550 name.c_str ()); 1551 } 1552 else if (stop_stack_dummy == STOP_NONE) 1553 { 1554 1555 /* We hit a breakpoint inside the FUNCTION. 1556 Keep the dummy frame, the user may want to examine its state. 1557 Discard inferior status, we're not at the same point 1558 we started at. */ 1559 discard_infcall_control_state (inf_status.release ()); 1560 1561 /* The following error message used to say "The expression 1562 which contained the function call has been discarded." 1563 It is a hard concept to explain in a few words. Ideally, 1564 GDB would be able to resume evaluation of the expression 1565 when the function finally is done executing. Perhaps 1566 someday this will be implemented (it would not be easy). */ 1567 /* FIXME: Insert a bunch of wrap_here; name can be very long if it's 1568 a C++ name with arguments and stuff. */ 1569 error (_("\ 1570 The program being debugged stopped while in a function called from GDB.\n\ 1571 Evaluation of the expression containing the function\n\ 1572 (%s) will be abandoned.\n\ 1573 When the function is done executing, GDB will silently stop."), 1574 name.c_str ()); 1575 } 1576 1577 } 1578 1579 /* The above code errors out, so ... */ 1580 gdb_assert_not_reached ("... should not be here"); 1581 } 1582 1583 void _initialize_infcall (); 1584 void 1585 _initialize_infcall () 1586 { 1587 add_setshow_boolean_cmd ("may-call-functions", no_class, 1588 &may_call_functions_p, _("\ 1589 Set permission to call functions in the program."), _("\ 1590 Show permission to call functions in the program."), _("\ 1591 When this permission is on, GDB may call functions in the program.\n\ 1592 Otherwise, any sort of attempt to call a function in the program\n\ 1593 will result in an error."), 1594 NULL, 1595 show_may_call_functions_p, 1596 &setlist, &showlist); 1597 1598 add_setshow_boolean_cmd ("coerce-float-to-double", class_obscure, 1599 &coerce_float_to_double_p, _("\ 1600 Set coercion of floats to doubles when calling functions."), _("\ 1601 Show coercion of floats to doubles when calling functions."), _("\ 1602 Variables of type float should generally be converted to doubles before\n\ 1603 calling an unprototyped function, and left alone when calling a prototyped\n\ 1604 function. However, some older debug info formats do not provide enough\n\ 1605 information to determine that a function is prototyped. If this flag is\n\ 1606 set, GDB will perform the conversion for a function it considers\n\ 1607 unprototyped.\n\ 1608 The default is to perform the conversion."), 1609 NULL, 1610 show_coerce_float_to_double_p, 1611 &setlist, &showlist); 1612 1613 add_setshow_boolean_cmd ("unwindonsignal", no_class, 1614 &unwind_on_signal_p, _("\ 1615 Set unwinding of stack if a signal is received while in a call dummy."), _("\ 1616 Show unwinding of stack if a signal is received while in a call dummy."), _("\ 1617 The unwindonsignal lets the user determine what gdb should do if a signal\n\ 1618 is received while in a function called from gdb (call dummy). If set, gdb\n\ 1619 unwinds the stack and restore the context to what as it was before the call.\n\ 1620 The default is to stop in the frame where the signal was received."), 1621 NULL, 1622 show_unwind_on_signal_p, 1623 &setlist, &showlist); 1624 1625 add_setshow_boolean_cmd ("unwind-on-terminating-exception", no_class, 1626 &unwind_on_terminating_exception_p, _("\ 1627 Set unwinding of stack if std::terminate is called while in call dummy."), _("\ 1628 Show unwinding of stack if std::terminate() is called while in a call dummy."), 1629 _("\ 1630 The unwind on terminating exception flag lets the user determine\n\ 1631 what gdb should do if a std::terminate() call is made from the\n\ 1632 default exception handler. If set, gdb unwinds the stack and restores\n\ 1633 the context to what it was before the call. If unset, gdb allows the\n\ 1634 std::terminate call to proceed.\n\ 1635 The default is to unwind the frame."), 1636 NULL, 1637 show_unwind_on_terminating_exception_p, 1638 &setlist, &showlist); 1639 1640 add_setshow_boolean_cmd 1641 ("infcall", class_maintenance, &debug_infcall, 1642 _("Set inferior call debugging."), 1643 _("Show inferior call debugging."), 1644 _("When on, inferior function call specific debugging is enabled."), 1645 NULL, show_debug_infcall, &setdebuglist, &showdebuglist); 1646 } 1647