1 /* Perform an inferior function call, for GDB, the GNU debugger. 2 3 Copyright (C) 1986-2012 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 "breakpoint.h" 22 #include "tracepoint.h" 23 #include "target.h" 24 #include "regcache.h" 25 #include "inferior.h" 26 #include "gdb_assert.h" 27 #include "block.h" 28 #include "gdbcore.h" 29 #include "language.h" 30 #include "objfiles.h" 31 #include "gdbcmd.h" 32 #include "command.h" 33 #include "gdb_string.h" 34 #include "infcall.h" 35 #include "dummy-frame.h" 36 #include "ada-lang.h" 37 #include "gdbthread.h" 38 #include "exceptions.h" 39 40 /* If we can't find a function's name from its address, 41 we print this instead. */ 42 #define RAW_FUNCTION_ADDRESS_FORMAT "at 0x%s" 43 #define RAW_FUNCTION_ADDRESS_SIZE (sizeof (RAW_FUNCTION_ADDRESS_FORMAT) \ 44 + 2 * sizeof (CORE_ADDR)) 45 46 /* NOTE: cagney/2003-04-16: What's the future of this code? 47 48 GDB needs an asynchronous expression evaluator, that means an 49 asynchronous inferior function call implementation, and that in 50 turn means restructuring the code so that it is event driven. */ 51 52 /* How you should pass arguments to a function depends on whether it 53 was defined in K&R style or prototype style. If you define a 54 function using the K&R syntax that takes a `float' argument, then 55 callers must pass that argument as a `double'. If you define the 56 function using the prototype syntax, then you must pass the 57 argument as a `float', with no promotion. 58 59 Unfortunately, on certain older platforms, the debug info doesn't 60 indicate reliably how each function was defined. A function type's 61 TYPE_FLAG_PROTOTYPED flag may be clear, even if the function was 62 defined in prototype style. When calling a function whose 63 TYPE_FLAG_PROTOTYPED flag is clear, GDB consults this flag to 64 decide what to do. 65 66 For modern targets, it is proper to assume that, if the prototype 67 flag is clear, that can be trusted: `float' arguments should be 68 promoted to `double'. For some older targets, if the prototype 69 flag is clear, that doesn't tell us anything. The default is to 70 trust the debug information; the user can override this behavior 71 with "set coerce-float-to-double 0". */ 72 73 static int coerce_float_to_double_p = 1; 74 static void 75 show_coerce_float_to_double_p (struct ui_file *file, int from_tty, 76 struct cmd_list_element *c, const char *value) 77 { 78 fprintf_filtered (file, 79 _("Coercion of floats to doubles " 80 "when calling functions is %s.\n"), 81 value); 82 } 83 84 /* This boolean tells what gdb should do if a signal is received while 85 in a function called from gdb (call dummy). If set, gdb unwinds 86 the stack and restore the context to what as it was before the 87 call. 88 89 The default is to stop in the frame where the signal was received. */ 90 91 int unwind_on_signal_p = 0; 92 static void 93 show_unwind_on_signal_p (struct ui_file *file, int from_tty, 94 struct cmd_list_element *c, const char *value) 95 { 96 fprintf_filtered (file, 97 _("Unwinding of stack if a signal is " 98 "received while in a call dummy is %s.\n"), 99 value); 100 } 101 102 /* This boolean tells what gdb should do if a std::terminate call is 103 made while in a function called from gdb (call dummy). 104 As the confines of a single dummy stack prohibit out-of-frame 105 handlers from handling a raised exception, and as out-of-frame 106 handlers are common in C++, this can lead to no handler being found 107 by the unwinder, and a std::terminate call. This is a false positive. 108 If set, gdb unwinds the stack and restores the context to what it 109 was before the call. 110 111 The default is to unwind the frame if a std::terminate call is 112 made. */ 113 114 static int unwind_on_terminating_exception_p = 1; 115 116 static void 117 show_unwind_on_terminating_exception_p (struct ui_file *file, int from_tty, 118 struct cmd_list_element *c, 119 const char *value) 120 121 { 122 fprintf_filtered (file, 123 _("Unwind stack if a C++ exception is " 124 "unhandled while in a call dummy is %s.\n"), 125 value); 126 } 127 128 /* Perform the standard coercions that are specified 129 for arguments to be passed to C or Ada functions. 130 131 If PARAM_TYPE is non-NULL, it is the expected parameter type. 132 IS_PROTOTYPED is non-zero if the function declaration is prototyped. 133 SP is the stack pointer were additional data can be pushed (updating 134 its value as needed). */ 135 136 static struct value * 137 value_arg_coerce (struct gdbarch *gdbarch, struct value *arg, 138 struct type *param_type, int is_prototyped, CORE_ADDR *sp) 139 { 140 const struct builtin_type *builtin = builtin_type (gdbarch); 141 struct type *arg_type = check_typedef (value_type (arg)); 142 struct type *type 143 = param_type ? check_typedef (param_type) : arg_type; 144 145 /* Perform any Ada-specific coercion first. */ 146 if (current_language->la_language == language_ada) 147 arg = ada_convert_actual (arg, type); 148 149 /* Force the value to the target if we will need its address. At 150 this point, we could allocate arguments on the stack instead of 151 calling malloc if we knew that their addresses would not be 152 saved by the called function. */ 153 arg = value_coerce_to_target (arg); 154 155 switch (TYPE_CODE (type)) 156 { 157 case TYPE_CODE_REF: 158 { 159 struct value *new_value; 160 161 if (TYPE_CODE (arg_type) == TYPE_CODE_REF) 162 return value_cast_pointers (type, arg); 163 164 /* Cast the value to the reference's target type, and then 165 convert it back to a reference. This will issue an error 166 if the value was not previously in memory - in some cases 167 we should clearly be allowing this, but how? */ 168 new_value = value_cast (TYPE_TARGET_TYPE (type), arg); 169 new_value = value_ref (new_value); 170 return new_value; 171 } 172 case TYPE_CODE_INT: 173 case TYPE_CODE_CHAR: 174 case TYPE_CODE_BOOL: 175 case TYPE_CODE_ENUM: 176 /* If we don't have a prototype, coerce to integer type if necessary. */ 177 if (!is_prototyped) 178 { 179 if (TYPE_LENGTH (type) < TYPE_LENGTH (builtin->builtin_int)) 180 type = builtin->builtin_int; 181 } 182 /* Currently all target ABIs require at least the width of an integer 183 type for an argument. We may have to conditionalize the following 184 type coercion for future targets. */ 185 if (TYPE_LENGTH (type) < TYPE_LENGTH (builtin->builtin_int)) 186 type = builtin->builtin_int; 187 break; 188 case TYPE_CODE_FLT: 189 if (!is_prototyped && coerce_float_to_double_p) 190 { 191 if (TYPE_LENGTH (type) < TYPE_LENGTH (builtin->builtin_double)) 192 type = builtin->builtin_double; 193 else if (TYPE_LENGTH (type) > TYPE_LENGTH (builtin->builtin_double)) 194 type = builtin->builtin_long_double; 195 } 196 break; 197 case TYPE_CODE_FUNC: 198 type = lookup_pointer_type (type); 199 break; 200 case TYPE_CODE_ARRAY: 201 /* Arrays are coerced to pointers to their first element, unless 202 they are vectors, in which case we want to leave them alone, 203 because they are passed by value. */ 204 if (current_language->c_style_arrays) 205 if (!TYPE_VECTOR (type)) 206 type = lookup_pointer_type (TYPE_TARGET_TYPE (type)); 207 break; 208 case TYPE_CODE_UNDEF: 209 case TYPE_CODE_PTR: 210 case TYPE_CODE_STRUCT: 211 case TYPE_CODE_UNION: 212 case TYPE_CODE_VOID: 213 case TYPE_CODE_SET: 214 case TYPE_CODE_RANGE: 215 case TYPE_CODE_STRING: 216 case TYPE_CODE_BITSTRING: 217 case TYPE_CODE_ERROR: 218 case TYPE_CODE_MEMBERPTR: 219 case TYPE_CODE_METHODPTR: 220 case TYPE_CODE_METHOD: 221 case TYPE_CODE_COMPLEX: 222 default: 223 break; 224 } 225 226 return value_cast (type, arg); 227 } 228 229 /* Return the return type of a function with its first instruction exactly at 230 the PC address. Return NULL otherwise. */ 231 232 static struct type * 233 find_function_return_type (CORE_ADDR pc) 234 { 235 struct symbol *sym = find_pc_function (pc); 236 237 if (sym != NULL && BLOCK_START (SYMBOL_BLOCK_VALUE (sym)) == pc 238 && SYMBOL_TYPE (sym) != NULL) 239 return TYPE_TARGET_TYPE (SYMBOL_TYPE (sym)); 240 241 return NULL; 242 } 243 244 /* Determine a function's address and its return type from its value. 245 Calls error() if the function is not valid for calling. */ 246 247 CORE_ADDR 248 find_function_addr (struct value *function, struct type **retval_type) 249 { 250 struct type *ftype = check_typedef (value_type (function)); 251 struct gdbarch *gdbarch = get_type_arch (ftype); 252 struct type *value_type = NULL; 253 /* Initialize it just to avoid a GCC false warning. */ 254 CORE_ADDR funaddr = 0; 255 256 /* If it's a member function, just look at the function 257 part of it. */ 258 259 /* Determine address to call. */ 260 if (TYPE_CODE (ftype) == TYPE_CODE_FUNC 261 || TYPE_CODE (ftype) == TYPE_CODE_METHOD) 262 funaddr = value_address (function); 263 else if (TYPE_CODE (ftype) == TYPE_CODE_PTR) 264 { 265 funaddr = value_as_address (function); 266 ftype = check_typedef (TYPE_TARGET_TYPE (ftype)); 267 if (TYPE_CODE (ftype) == TYPE_CODE_FUNC 268 || TYPE_CODE (ftype) == TYPE_CODE_METHOD) 269 funaddr = gdbarch_convert_from_func_ptr_addr (gdbarch, funaddr, 270 ¤t_target); 271 } 272 if (TYPE_CODE (ftype) == TYPE_CODE_FUNC 273 || TYPE_CODE (ftype) == TYPE_CODE_METHOD) 274 { 275 value_type = TYPE_TARGET_TYPE (ftype); 276 277 if (TYPE_GNU_IFUNC (ftype)) 278 { 279 funaddr = gnu_ifunc_resolve_addr (gdbarch, funaddr); 280 281 /* Skip querying the function symbol if no RETVAL_TYPE has been 282 asked for. */ 283 if (retval_type) 284 value_type = find_function_return_type (funaddr); 285 } 286 } 287 else if (TYPE_CODE (ftype) == TYPE_CODE_INT) 288 { 289 /* Handle the case of functions lacking debugging info. 290 Their values are characters since their addresses are char. */ 291 if (TYPE_LENGTH (ftype) == 1) 292 funaddr = value_as_address (value_addr (function)); 293 else 294 { 295 /* Handle function descriptors lacking debug info. */ 296 int found_descriptor = 0; 297 298 funaddr = 0; /* pacify "gcc -Werror" */ 299 if (VALUE_LVAL (function) == lval_memory) 300 { 301 CORE_ADDR nfunaddr; 302 303 funaddr = value_as_address (value_addr (function)); 304 nfunaddr = funaddr; 305 funaddr = gdbarch_convert_from_func_ptr_addr (gdbarch, funaddr, 306 ¤t_target); 307 if (funaddr != nfunaddr) 308 found_descriptor = 1; 309 } 310 if (!found_descriptor) 311 /* Handle integer used as address of a function. */ 312 funaddr = (CORE_ADDR) value_as_long (function); 313 } 314 } 315 else 316 error (_("Invalid data type for function to be called.")); 317 318 if (retval_type != NULL) 319 *retval_type = value_type; 320 return funaddr + gdbarch_deprecated_function_start_offset (gdbarch); 321 } 322 323 /* For CALL_DUMMY_ON_STACK, push a breakpoint sequence that the called 324 function returns to. */ 325 326 static CORE_ADDR 327 push_dummy_code (struct gdbarch *gdbarch, 328 CORE_ADDR sp, CORE_ADDR funaddr, 329 struct value **args, int nargs, 330 struct type *value_type, 331 CORE_ADDR *real_pc, CORE_ADDR *bp_addr, 332 struct regcache *regcache) 333 { 334 gdb_assert (gdbarch_push_dummy_code_p (gdbarch)); 335 336 return gdbarch_push_dummy_code (gdbarch, sp, funaddr, 337 args, nargs, value_type, real_pc, bp_addr, 338 regcache); 339 } 340 341 /* Fetch the name of the function at FUNADDR. 342 This is used in printing an error message for call_function_by_hand. 343 BUF is used to print FUNADDR in hex if the function name cannot be 344 determined. It must be large enough to hold formatted result of 345 RAW_FUNCTION_ADDRESS_FORMAT. */ 346 347 static const char * 348 get_function_name (CORE_ADDR funaddr, char *buf, int buf_size) 349 { 350 { 351 struct symbol *symbol = find_pc_function (funaddr); 352 353 if (symbol) 354 return SYMBOL_PRINT_NAME (symbol); 355 } 356 357 { 358 /* Try the minimal symbols. */ 359 struct minimal_symbol *msymbol = lookup_minimal_symbol_by_pc (funaddr); 360 361 if (msymbol) 362 return SYMBOL_PRINT_NAME (msymbol); 363 } 364 365 { 366 char *tmp = xstrprintf (_(RAW_FUNCTION_ADDRESS_FORMAT), 367 hex_string (funaddr)); 368 369 gdb_assert (strlen (tmp) + 1 <= buf_size); 370 strcpy (buf, tmp); 371 xfree (tmp); 372 return buf; 373 } 374 } 375 376 /* Subroutine of call_function_by_hand to simplify it. 377 Start up the inferior and wait for it to stop. 378 Return the exception if there's an error, or an exception with 379 reason >= 0 if there's no error. 380 381 This is done inside a TRY_CATCH so the caller needn't worry about 382 thrown errors. The caller should rethrow if there's an error. */ 383 384 static struct gdb_exception 385 run_inferior_call (struct thread_info *call_thread, CORE_ADDR real_pc) 386 { 387 volatile struct gdb_exception e; 388 int saved_in_infcall = call_thread->control.in_infcall; 389 ptid_t call_thread_ptid = call_thread->ptid; 390 391 call_thread->control.in_infcall = 1; 392 393 clear_proceed_status (); 394 395 disable_watchpoints_before_interactive_call_start (); 396 397 /* We want stop_registers, please... */ 398 call_thread->control.proceed_to_finish = 1; 399 400 TRY_CATCH (e, RETURN_MASK_ALL) 401 { 402 proceed (real_pc, TARGET_SIGNAL_0, 0); 403 404 /* Inferior function calls are always synchronous, even if the 405 target supports asynchronous execution. Do here what 406 `proceed' itself does in sync mode. */ 407 if (target_can_async_p () && is_running (inferior_ptid)) 408 { 409 wait_for_inferior (); 410 normal_stop (); 411 } 412 } 413 414 /* At this point the current thread may have changed. Refresh 415 CALL_THREAD as it could be invalid if its thread has exited. */ 416 call_thread = find_thread_ptid (call_thread_ptid); 417 418 enable_watchpoints_after_interactive_call_stop (); 419 420 /* Call breakpoint_auto_delete on the current contents of the bpstat 421 of inferior call thread. 422 If all error()s out of proceed ended up calling normal_stop 423 (and perhaps they should; it already does in the special case 424 of error out of resume()), then we wouldn't need this. */ 425 if (e.reason < 0) 426 { 427 if (call_thread != NULL) 428 breakpoint_auto_delete (call_thread->control.stop_bpstat); 429 } 430 431 if (call_thread != NULL) 432 call_thread->control.in_infcall = saved_in_infcall; 433 434 return e; 435 } 436 437 /* A cleanup function that calls delete_std_terminate_breakpoint. */ 438 static void 439 cleanup_delete_std_terminate_breakpoint (void *ignore) 440 { 441 delete_std_terminate_breakpoint (); 442 } 443 444 /* All this stuff with a dummy frame may seem unnecessarily complicated 445 (why not just save registers in GDB?). The purpose of pushing a dummy 446 frame which looks just like a real frame is so that if you call a 447 function and then hit a breakpoint (get a signal, etc), "backtrace" 448 will look right. Whether the backtrace needs to actually show the 449 stack at the time the inferior function was called is debatable, but 450 it certainly needs to not display garbage. So if you are contemplating 451 making dummy frames be different from normal frames, consider that. */ 452 453 /* Perform a function call in the inferior. 454 ARGS is a vector of values of arguments (NARGS of them). 455 FUNCTION is a value, the function to be called. 456 Returns a value representing what the function returned. 457 May fail to return, if a breakpoint or signal is hit 458 during the execution of the function. 459 460 ARGS is modified to contain coerced values. */ 461 462 struct value * 463 call_function_by_hand (struct value *function, int nargs, struct value **args) 464 { 465 CORE_ADDR sp; 466 struct type *values_type, *target_values_type; 467 unsigned char struct_return = 0, lang_struct_return = 0; 468 CORE_ADDR struct_addr = 0; 469 struct infcall_control_state *inf_status; 470 struct cleanup *inf_status_cleanup; 471 struct infcall_suspend_state *caller_state; 472 CORE_ADDR funaddr; 473 CORE_ADDR real_pc; 474 struct type *ftype = check_typedef (value_type (function)); 475 CORE_ADDR bp_addr; 476 struct frame_id dummy_id; 477 struct cleanup *args_cleanup; 478 struct frame_info *frame; 479 struct gdbarch *gdbarch; 480 struct cleanup *terminate_bp_cleanup; 481 ptid_t call_thread_ptid; 482 struct gdb_exception e; 483 char name_buf[RAW_FUNCTION_ADDRESS_SIZE]; 484 485 if (TYPE_CODE (ftype) == TYPE_CODE_PTR) 486 ftype = check_typedef (TYPE_TARGET_TYPE (ftype)); 487 488 if (!target_has_execution) 489 noprocess (); 490 491 if (get_traceframe_number () >= 0) 492 error (_("May not call functions while looking at trace frames.")); 493 494 if (execution_direction == EXEC_REVERSE) 495 error (_("Cannot call functions in reverse mode.")); 496 497 frame = get_current_frame (); 498 gdbarch = get_frame_arch (frame); 499 500 if (!gdbarch_push_dummy_call_p (gdbarch)) 501 error (_("This target does not support function calls.")); 502 503 /* A cleanup for the inferior status. 504 This is only needed while we're preparing the inferior function call. */ 505 inf_status = save_infcall_control_state (); 506 inf_status_cleanup 507 = make_cleanup_restore_infcall_control_state (inf_status); 508 509 /* Save the caller's registers and other state associated with the 510 inferior itself so that they can be restored once the 511 callee returns. To allow nested calls the registers are (further 512 down) pushed onto a dummy frame stack. Include a cleanup (which 513 is tossed once the regcache has been pushed). */ 514 caller_state = save_infcall_suspend_state (); 515 make_cleanup_restore_infcall_suspend_state (caller_state); 516 517 /* Ensure that the initial SP is correctly aligned. */ 518 { 519 CORE_ADDR old_sp = get_frame_sp (frame); 520 521 if (gdbarch_frame_align_p (gdbarch)) 522 { 523 sp = gdbarch_frame_align (gdbarch, old_sp); 524 /* NOTE: cagney/2003-08-13: Skip the "red zone". For some 525 ABIs, a function can use memory beyond the inner most stack 526 address. AMD64 called that region the "red zone". Skip at 527 least the "red zone" size before allocating any space on 528 the stack. */ 529 if (gdbarch_inner_than (gdbarch, 1, 2)) 530 sp -= gdbarch_frame_red_zone_size (gdbarch); 531 else 532 sp += gdbarch_frame_red_zone_size (gdbarch); 533 /* Still aligned? */ 534 gdb_assert (sp == gdbarch_frame_align (gdbarch, sp)); 535 /* NOTE: cagney/2002-09-18: 536 537 On a RISC architecture, a void parameterless generic dummy 538 frame (i.e., no parameters, no result) typically does not 539 need to push anything the stack and hence can leave SP and 540 FP. Similarly, a frameless (possibly leaf) function does 541 not push anything on the stack and, hence, that too can 542 leave FP and SP unchanged. As a consequence, a sequence of 543 void parameterless generic dummy frame calls to frameless 544 functions will create a sequence of effectively identical 545 frames (SP, FP and TOS and PC the same). This, not 546 suprisingly, results in what appears to be a stack in an 547 infinite loop --- when GDB tries to find a generic dummy 548 frame on the internal dummy frame stack, it will always 549 find the first one. 550 551 To avoid this problem, the code below always grows the 552 stack. That way, two dummy frames can never be identical. 553 It does burn a few bytes of stack but that is a small price 554 to pay :-). */ 555 if (sp == old_sp) 556 { 557 if (gdbarch_inner_than (gdbarch, 1, 2)) 558 /* Stack grows down. */ 559 sp = gdbarch_frame_align (gdbarch, old_sp - 1); 560 else 561 /* Stack grows up. */ 562 sp = gdbarch_frame_align (gdbarch, old_sp + 1); 563 } 564 /* SP may have underflown address zero here from OLD_SP. Memory access 565 functions will probably fail in such case but that is a target's 566 problem. */ 567 } 568 else 569 /* FIXME: cagney/2002-09-18: Hey, you loose! 570 571 Who knows how badly aligned the SP is! 572 573 If the generic dummy frame ends up empty (because nothing is 574 pushed) GDB won't be able to correctly perform back traces. 575 If a target is having trouble with backtraces, first thing to 576 do is add FRAME_ALIGN() to the architecture vector. If that 577 fails, try dummy_id(). 578 579 If the ABI specifies a "Red Zone" (see the doco) the code 580 below will quietly trash it. */ 581 sp = old_sp; 582 } 583 584 funaddr = find_function_addr (function, &values_type); 585 if (!values_type) 586 values_type = builtin_type (gdbarch)->builtin_int; 587 588 CHECK_TYPEDEF (values_type); 589 590 /* Are we returning a value using a structure return (passing a 591 hidden argument pointing to storage) or a normal value return? 592 There are two cases: language-mandated structure return and 593 target ABI structure return. The variable STRUCT_RETURN only 594 describes the latter. The language version is handled by passing 595 the return location as the first parameter to the function, 596 even preceding "this". This is different from the target 597 ABI version, which is target-specific; for instance, on ia64 598 the first argument is passed in out0 but the hidden structure 599 return pointer would normally be passed in r8. */ 600 601 if (language_pass_by_reference (values_type)) 602 { 603 lang_struct_return = 1; 604 605 /* Tell the target specific argument pushing routine not to 606 expect a value. */ 607 target_values_type = builtin_type (gdbarch)->builtin_void; 608 } 609 else 610 { 611 struct_return = using_struct_return (gdbarch, 612 value_type (function), values_type); 613 target_values_type = values_type; 614 } 615 616 /* Determine the location of the breakpoint (and possibly other 617 stuff) that the called function will return to. The SPARC, for a 618 function returning a structure or union, needs to make space for 619 not just the breakpoint but also an extra word containing the 620 size (?) of the structure being passed. */ 621 622 /* The actual breakpoint (at BP_ADDR) is inserted separatly so there 623 is no need to write that out. */ 624 625 switch (gdbarch_call_dummy_location (gdbarch)) 626 { 627 case ON_STACK: 628 sp = push_dummy_code (gdbarch, sp, funaddr, 629 args, nargs, target_values_type, 630 &real_pc, &bp_addr, get_current_regcache ()); 631 break; 632 case AT_ENTRY_POINT: 633 { 634 CORE_ADDR dummy_addr; 635 636 real_pc = funaddr; 637 dummy_addr = entry_point_address (); 638 /* A call dummy always consists of just a single breakpoint, so 639 its address is the same as the address of the dummy. */ 640 bp_addr = dummy_addr; 641 break; 642 } 643 case AT_SYMBOL: 644 /* Some executables define a symbol __CALL_DUMMY_ADDRESS whose 645 address is the location where the breakpoint should be 646 placed. Once all targets are using the overhauled frame code 647 this can be deleted - ON_STACK is a better option. */ 648 { 649 struct minimal_symbol *sym; 650 CORE_ADDR dummy_addr; 651 652 sym = lookup_minimal_symbol ("__CALL_DUMMY_ADDRESS", NULL, NULL); 653 real_pc = funaddr; 654 if (sym) 655 { 656 dummy_addr = SYMBOL_VALUE_ADDRESS (sym); 657 /* Make certain that the address points at real code, and not 658 a function descriptor. */ 659 dummy_addr = gdbarch_convert_from_func_ptr_addr (gdbarch, 660 dummy_addr, 661 ¤t_target); 662 } 663 else 664 dummy_addr = entry_point_address (); 665 /* A call dummy always consists of just a single breakpoint, 666 so it's address is the same as the address of the dummy. */ 667 bp_addr = dummy_addr; 668 break; 669 } 670 default: 671 internal_error (__FILE__, __LINE__, _("bad switch")); 672 } 673 674 if (nargs < TYPE_NFIELDS (ftype)) 675 error (_("Too few arguments in function call.")); 676 677 { 678 int i; 679 680 for (i = nargs - 1; i >= 0; i--) 681 { 682 int prototyped; 683 struct type *param_type; 684 685 /* FIXME drow/2002-05-31: Should just always mark methods as 686 prototyped. Can we respect TYPE_VARARGS? Probably not. */ 687 if (TYPE_CODE (ftype) == TYPE_CODE_METHOD) 688 prototyped = 1; 689 else if (i < TYPE_NFIELDS (ftype)) 690 prototyped = TYPE_PROTOTYPED (ftype); 691 else 692 prototyped = 0; 693 694 if (i < TYPE_NFIELDS (ftype)) 695 param_type = TYPE_FIELD_TYPE (ftype, i); 696 else 697 param_type = NULL; 698 699 args[i] = value_arg_coerce (gdbarch, args[i], 700 param_type, prototyped, &sp); 701 702 if (param_type != NULL && language_pass_by_reference (param_type)) 703 args[i] = value_addr (args[i]); 704 } 705 } 706 707 /* Reserve space for the return structure to be written on the 708 stack, if necessary. Make certain that the value is correctly 709 aligned. */ 710 711 if (struct_return || lang_struct_return) 712 { 713 int len = TYPE_LENGTH (values_type); 714 715 if (gdbarch_inner_than (gdbarch, 1, 2)) 716 { 717 /* Stack grows downward. Align STRUCT_ADDR and SP after 718 making space for the return value. */ 719 sp -= len; 720 if (gdbarch_frame_align_p (gdbarch)) 721 sp = gdbarch_frame_align (gdbarch, sp); 722 struct_addr = sp; 723 } 724 else 725 { 726 /* Stack grows upward. Align the frame, allocate space, and 727 then again, re-align the frame??? */ 728 if (gdbarch_frame_align_p (gdbarch)) 729 sp = gdbarch_frame_align (gdbarch, sp); 730 struct_addr = sp; 731 sp += len; 732 if (gdbarch_frame_align_p (gdbarch)) 733 sp = gdbarch_frame_align (gdbarch, sp); 734 } 735 } 736 737 if (lang_struct_return) 738 { 739 struct value **new_args; 740 741 /* Add the new argument to the front of the argument list. */ 742 new_args = xmalloc (sizeof (struct value *) * (nargs + 1)); 743 new_args[0] = value_from_pointer (lookup_pointer_type (values_type), 744 struct_addr); 745 memcpy (&new_args[1], &args[0], sizeof (struct value *) * nargs); 746 args = new_args; 747 nargs++; 748 args_cleanup = make_cleanup (xfree, args); 749 } 750 else 751 args_cleanup = make_cleanup (null_cleanup, NULL); 752 753 /* Create the dummy stack frame. Pass in the call dummy address as, 754 presumably, the ABI code knows where, in the call dummy, the 755 return address should be pointed. */ 756 sp = gdbarch_push_dummy_call (gdbarch, function, get_current_regcache (), 757 bp_addr, nargs, args, 758 sp, struct_return, struct_addr); 759 760 do_cleanups (args_cleanup); 761 762 /* Set up a frame ID for the dummy frame so we can pass it to 763 set_momentary_breakpoint. We need to give the breakpoint a frame 764 ID so that the breakpoint code can correctly re-identify the 765 dummy breakpoint. */ 766 /* Sanity. The exact same SP value is returned by PUSH_DUMMY_CALL, 767 saved as the dummy-frame TOS, and used by dummy_id to form 768 the frame ID's stack address. */ 769 dummy_id = frame_id_build (sp, bp_addr); 770 771 /* Create a momentary breakpoint at the return address of the 772 inferior. That way it breaks when it returns. */ 773 774 { 775 struct breakpoint *bpt; 776 struct symtab_and_line sal; 777 778 init_sal (&sal); /* initialize to zeroes */ 779 sal.pspace = current_program_space; 780 sal.pc = bp_addr; 781 sal.section = find_pc_overlay (sal.pc); 782 /* Sanity. The exact same SP value is returned by 783 PUSH_DUMMY_CALL, saved as the dummy-frame TOS, and used by 784 dummy_id to form the frame ID's stack address. */ 785 bpt = set_momentary_breakpoint (gdbarch, sal, dummy_id, bp_call_dummy); 786 bpt->disposition = disp_del; 787 } 788 789 /* Create a breakpoint in std::terminate. 790 If a C++ exception is raised in the dummy-frame, and the 791 exception handler is (normally, and expected to be) out-of-frame, 792 the default C++ handler will (wrongly) be called in an inferior 793 function call. This is wrong, as an exception can be normally 794 and legally handled out-of-frame. The confines of the dummy frame 795 prevent the unwinder from finding the correct handler (or any 796 handler, unless it is in-frame). The default handler calls 797 std::terminate. This will kill the inferior. Assert that 798 terminate should never be called in an inferior function 799 call. Place a momentary breakpoint in the std::terminate function 800 and if triggered in the call, rewind. */ 801 if (unwind_on_terminating_exception_p) 802 set_std_terminate_breakpoint (); 803 804 /* Everything's ready, push all the info needed to restore the 805 caller (and identify the dummy-frame) onto the dummy-frame 806 stack. */ 807 dummy_frame_push (caller_state, &dummy_id); 808 809 /* Discard both inf_status and caller_state cleanups. 810 From this point on we explicitly restore the associated state 811 or discard it. */ 812 discard_cleanups (inf_status_cleanup); 813 814 /* Register a clean-up for unwind_on_terminating_exception_breakpoint. */ 815 terminate_bp_cleanup = make_cleanup (cleanup_delete_std_terminate_breakpoint, 816 NULL); 817 818 /* - SNIP - SNIP - SNIP - SNIP - SNIP - SNIP - SNIP - SNIP - SNIP - 819 If you're looking to implement asynchronous dummy-frames, then 820 just below is the place to chop this function in two.. */ 821 822 /* TP is invalid after run_inferior_call returns, so enclose this 823 in a block so that it's only in scope during the time it's valid. */ 824 { 825 struct thread_info *tp = inferior_thread (); 826 827 /* Save this thread's ptid, we need it later but the thread 828 may have exited. */ 829 call_thread_ptid = tp->ptid; 830 831 /* Run the inferior until it stops. */ 832 833 e = run_inferior_call (tp, real_pc); 834 } 835 836 /* Rethrow an error if we got one trying to run the inferior. */ 837 838 if (e.reason < 0) 839 { 840 const char *name = get_function_name (funaddr, 841 name_buf, sizeof (name_buf)); 842 843 discard_infcall_control_state (inf_status); 844 845 /* We could discard the dummy frame here if the program exited, 846 but it will get garbage collected the next time the program is 847 run anyway. */ 848 849 switch (e.reason) 850 { 851 case RETURN_ERROR: 852 throw_error (e.error, _("%s\n\ 853 An error occurred while in a function called from GDB.\n\ 854 Evaluation of the expression containing the function\n\ 855 (%s) will be abandoned.\n\ 856 When the function is done executing, GDB will silently stop."), 857 e.message, name); 858 case RETURN_QUIT: 859 default: 860 throw_exception (e); 861 } 862 } 863 864 /* If the program has exited, or we stopped at a different thread, 865 exit and inform the user. */ 866 867 if (! target_has_execution) 868 { 869 const char *name = get_function_name (funaddr, 870 name_buf, sizeof (name_buf)); 871 872 /* If we try to restore the inferior status, 873 we'll crash as the inferior is no longer running. */ 874 discard_infcall_control_state (inf_status); 875 876 /* We could discard the dummy frame here given that the program exited, 877 but it will get garbage collected the next time the program is 878 run anyway. */ 879 880 error (_("The program being debugged exited while in a function " 881 "called from GDB.\n" 882 "Evaluation of the expression containing the function\n" 883 "(%s) will be abandoned."), 884 name); 885 } 886 887 if (! ptid_equal (call_thread_ptid, inferior_ptid)) 888 { 889 const char *name = get_function_name (funaddr, 890 name_buf, sizeof (name_buf)); 891 892 /* We've switched threads. This can happen if another thread gets a 893 signal or breakpoint while our thread was running. 894 There's no point in restoring the inferior status, 895 we're in a different thread. */ 896 discard_infcall_control_state (inf_status); 897 /* Keep the dummy frame record, if the user switches back to the 898 thread with the hand-call, we'll need it. */ 899 if (stopped_by_random_signal) 900 error (_("\ 901 The program received a signal in another thread while\n\ 902 making a function call from GDB.\n\ 903 Evaluation of the expression containing the function\n\ 904 (%s) will be abandoned.\n\ 905 When the function is done executing, GDB will silently stop."), 906 name); 907 else 908 error (_("\ 909 The program stopped in another thread while making a function call from GDB.\n\ 910 Evaluation of the expression containing the function\n\ 911 (%s) will be abandoned.\n\ 912 When the function is done executing, GDB will silently stop."), 913 name); 914 } 915 916 if (stopped_by_random_signal || stop_stack_dummy != STOP_STACK_DUMMY) 917 { 918 const char *name = get_function_name (funaddr, 919 name_buf, sizeof (name_buf)); 920 921 if (stopped_by_random_signal) 922 { 923 /* We stopped inside the FUNCTION because of a random 924 signal. Further execution of the FUNCTION is not 925 allowed. */ 926 927 if (unwind_on_signal_p) 928 { 929 /* The user wants the context restored. */ 930 931 /* We must get back to the frame we were before the 932 dummy call. */ 933 dummy_frame_pop (dummy_id); 934 935 /* We also need to restore inferior status to that before the 936 dummy call. */ 937 restore_infcall_control_state (inf_status); 938 939 /* FIXME: Insert a bunch of wrap_here; name can be very 940 long if it's a C++ name with arguments and stuff. */ 941 error (_("\ 942 The program being debugged was signaled while in a function called from GDB.\n\ 943 GDB has restored the context to what it was before the call.\n\ 944 To change this behavior use \"set unwindonsignal off\".\n\ 945 Evaluation of the expression containing the function\n\ 946 (%s) will be abandoned."), 947 name); 948 } 949 else 950 { 951 /* The user wants to stay in the frame where we stopped 952 (default). 953 Discard inferior status, we're not at the same point 954 we started at. */ 955 discard_infcall_control_state (inf_status); 956 957 /* FIXME: Insert a bunch of wrap_here; name can be very 958 long if it's a C++ name with arguments and stuff. */ 959 error (_("\ 960 The program being debugged was signaled while in a function called from GDB.\n\ 961 GDB remains in the frame where the signal was received.\n\ 962 To change this behavior use \"set unwindonsignal on\".\n\ 963 Evaluation of the expression containing the function\n\ 964 (%s) will be abandoned.\n\ 965 When the function is done executing, GDB will silently stop."), 966 name); 967 } 968 } 969 970 if (stop_stack_dummy == STOP_STD_TERMINATE) 971 { 972 /* We must get back to the frame we were before the dummy 973 call. */ 974 dummy_frame_pop (dummy_id); 975 976 /* We also need to restore inferior status to that before 977 the dummy call. */ 978 restore_infcall_control_state (inf_status); 979 980 error (_("\ 981 The program being debugged entered a std::terminate call, most likely\n\ 982 caused by an unhandled C++ exception. GDB blocked this call in order\n\ 983 to prevent the program from being terminated, and has restored the\n\ 984 context to its original state before the call.\n\ 985 To change this behaviour use \"set unwind-on-terminating-exception off\".\n\ 986 Evaluation of the expression containing the function (%s)\n\ 987 will be abandoned."), 988 name); 989 } 990 else if (stop_stack_dummy == STOP_NONE) 991 { 992 993 /* We hit a breakpoint inside the FUNCTION. 994 Keep the dummy frame, the user may want to examine its state. 995 Discard inferior status, we're not at the same point 996 we started at. */ 997 discard_infcall_control_state (inf_status); 998 999 /* The following error message used to say "The expression 1000 which contained the function call has been discarded." 1001 It is a hard concept to explain in a few words. Ideally, 1002 GDB would be able to resume evaluation of the expression 1003 when the function finally is done executing. Perhaps 1004 someday this will be implemented (it would not be easy). */ 1005 /* FIXME: Insert a bunch of wrap_here; name can be very long if it's 1006 a C++ name with arguments and stuff. */ 1007 error (_("\ 1008 The program being debugged stopped while in a function called from GDB.\n\ 1009 Evaluation of the expression containing the function\n\ 1010 (%s) will be abandoned.\n\ 1011 When the function is done executing, GDB will silently stop."), 1012 name); 1013 } 1014 1015 /* The above code errors out, so ... */ 1016 internal_error (__FILE__, __LINE__, _("... should not be here")); 1017 } 1018 1019 do_cleanups (terminate_bp_cleanup); 1020 1021 /* If we get here the called FUNCTION ran to completion, 1022 and the dummy frame has already been popped. */ 1023 1024 { 1025 struct address_space *aspace = get_regcache_aspace (stop_registers); 1026 struct regcache *retbuf = regcache_xmalloc (gdbarch, aspace); 1027 struct cleanup *retbuf_cleanup = make_cleanup_regcache_xfree (retbuf); 1028 struct value *retval = NULL; 1029 1030 regcache_cpy_no_passthrough (retbuf, stop_registers); 1031 1032 /* Inferior call is successful. Restore the inferior status. 1033 At this stage, leave the RETBUF alone. */ 1034 restore_infcall_control_state (inf_status); 1035 1036 /* Figure out the value returned by the function. */ 1037 retval = allocate_value (values_type); 1038 1039 if (lang_struct_return) 1040 read_value_memory (retval, 0, 1, struct_addr, 1041 value_contents_raw (retval), 1042 TYPE_LENGTH (values_type)); 1043 else if (TYPE_CODE (target_values_type) != TYPE_CODE_VOID) 1044 { 1045 /* If the function returns void, don't bother fetching the 1046 return value. */ 1047 switch (gdbarch_return_value (gdbarch, value_type (function), 1048 target_values_type, NULL, NULL, NULL)) 1049 { 1050 case RETURN_VALUE_REGISTER_CONVENTION: 1051 case RETURN_VALUE_ABI_RETURNS_ADDRESS: 1052 case RETURN_VALUE_ABI_PRESERVES_ADDRESS: 1053 gdbarch_return_value (gdbarch, value_type (function), values_type, 1054 retbuf, value_contents_raw (retval), NULL); 1055 break; 1056 case RETURN_VALUE_STRUCT_CONVENTION: 1057 read_value_memory (retval, 0, 1, struct_addr, 1058 value_contents_raw (retval), 1059 TYPE_LENGTH (values_type)); 1060 break; 1061 } 1062 } 1063 1064 do_cleanups (retbuf_cleanup); 1065 1066 gdb_assert (retval); 1067 return retval; 1068 } 1069 } 1070 1071 1072 /* Provide a prototype to silence -Wmissing-prototypes. */ 1073 void _initialize_infcall (void); 1074 1075 void 1076 _initialize_infcall (void) 1077 { 1078 add_setshow_boolean_cmd ("coerce-float-to-double", class_obscure, 1079 &coerce_float_to_double_p, _("\ 1080 Set coercion of floats to doubles when calling functions."), _("\ 1081 Show coercion of floats to doubles when calling functions"), _("\ 1082 Variables of type float should generally be converted to doubles before\n\ 1083 calling an unprototyped function, and left alone when calling a prototyped\n\ 1084 function. However, some older debug info formats do not provide enough\n\ 1085 information to determine that a function is prototyped. If this flag is\n\ 1086 set, GDB will perform the conversion for a function it considers\n\ 1087 unprototyped.\n\ 1088 The default is to perform the conversion.\n"), 1089 NULL, 1090 show_coerce_float_to_double_p, 1091 &setlist, &showlist); 1092 1093 add_setshow_boolean_cmd ("unwindonsignal", no_class, 1094 &unwind_on_signal_p, _("\ 1095 Set unwinding of stack if a signal is received while in a call dummy."), _("\ 1096 Show unwinding of stack if a signal is received while in a call dummy."), _("\ 1097 The unwindonsignal lets the user determine what gdb should do if a signal\n\ 1098 is received while in a function called from gdb (call dummy). If set, gdb\n\ 1099 unwinds the stack and restore the context to what as it was before the call.\n\ 1100 The default is to stop in the frame where the signal was received."), 1101 NULL, 1102 show_unwind_on_signal_p, 1103 &setlist, &showlist); 1104 1105 add_setshow_boolean_cmd ("unwind-on-terminating-exception", no_class, 1106 &unwind_on_terminating_exception_p, _("\ 1107 Set unwinding of stack if std::terminate is called while in call dummy."), _("\ 1108 Show unwinding of stack if std::terminate() is called while in a call dummy."), 1109 _("\ 1110 The unwind on terminating exception flag lets the user determine\n\ 1111 what gdb should do if a std::terminate() call is made from the\n\ 1112 default exception handler. If set, gdb unwinds the stack and restores\n\ 1113 the context to what it was before the call. If unset, gdb allows the\n\ 1114 std::terminate call to proceed.\n\ 1115 The default is to unwind the frame."), 1116 NULL, 1117 show_unwind_on_terminating_exception_p, 1118 &setlist, &showlist); 1119 1120 } 1121