1 /* Perform an inferior function call, for GDB, the GNU debugger.
3 Copyright (C) 1986-2014 Free Software Foundation, Inc.
5 This file is part of GDB.
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.
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.
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/>. */
21 #include "breakpoint.h"
22 #include "tracepoint.h"
27 #include "gdb_assert.h"
36 #include "dummy-frame.h"
38 #include "gdbthread.h"
39 #include "exceptions.h"
40 #include "event-top.h"
42 /* If we can't find a function's name from its address,
43 we print this instead. */
44 #define RAW_FUNCTION_ADDRESS_FORMAT "at 0x%s"
45 #define RAW_FUNCTION_ADDRESS_SIZE (sizeof (RAW_FUNCTION_ADDRESS_FORMAT) \
46 + 2 * sizeof (CORE_ADDR))
48 /* NOTE: cagney/2003-04-16: What's the future of this code?
50 GDB needs an asynchronous expression evaluator, that means an
51 asynchronous inferior function call implementation, and that in
52 turn means restructuring the code so that it is event driven. */
54 /* How you should pass arguments to a function depends on whether it
55 was defined in K&R style or prototype style. If you define a
56 function using the K&R syntax that takes a `float' argument, then
57 callers must pass that argument as a `double'. If you define the
58 function using the prototype syntax, then you must pass the
59 argument as a `float', with no promotion.
61 Unfortunately, on certain older platforms, the debug info doesn't
62 indicate reliably how each function was defined. A function type's
63 TYPE_FLAG_PROTOTYPED flag may be clear, even if the function was
64 defined in prototype style. When calling a function whose
65 TYPE_FLAG_PROTOTYPED flag is clear, GDB consults this flag to
68 For modern targets, it is proper to assume that, if the prototype
69 flag is clear, that can be trusted: `float' arguments should be
70 promoted to `double'. For some older targets, if the prototype
71 flag is clear, that doesn't tell us anything. The default is to
72 trust the debug information; the user can override this behavior
73 with "set coerce-float-to-double 0". */
75 static int coerce_float_to_double_p = 1;
77 show_coerce_float_to_double_p (struct ui_file *file, int from_tty,
78 struct cmd_list_element *c, const char *value)
80 fprintf_filtered (file,
81 _("Coercion of floats to doubles "
82 "when calling functions is %s.\n"),
86 /* This boolean tells what gdb should do if a signal is received while
87 in a function called from gdb (call dummy). If set, gdb unwinds
88 the stack and restore the context to what as it was before the
91 The default is to stop in the frame where the signal was received. */
93 static int unwind_on_signal_p = 0;
95 show_unwind_on_signal_p (struct ui_file *file, int from_tty,
96 struct cmd_list_element *c, const char *value)
98 fprintf_filtered (file,
99 _("Unwinding of stack if a signal is "
100 "received while in a call dummy is %s.\n"),
104 /* This boolean tells what gdb should do if a std::terminate call is
105 made while in a function called from gdb (call dummy).
106 As the confines of a single dummy stack prohibit out-of-frame
107 handlers from handling a raised exception, and as out-of-frame
108 handlers are common in C++, this can lead to no handler being found
109 by the unwinder, and a std::terminate call. This is a false positive.
110 If set, gdb unwinds the stack and restores the context to what it
113 The default is to unwind the frame if a std::terminate call is
116 static int unwind_on_terminating_exception_p = 1;
119 show_unwind_on_terminating_exception_p (struct ui_file *file, int from_tty,
120 struct cmd_list_element *c,
124 fprintf_filtered (file,
125 _("Unwind stack if a C++ exception is "
126 "unhandled while in a call dummy is %s.\n"),
130 /* Perform the standard coercions that are specified
131 for arguments to be passed to C or Ada functions.
133 If PARAM_TYPE is non-NULL, it is the expected parameter type.
134 IS_PROTOTYPED is non-zero if the function declaration is prototyped.
135 SP is the stack pointer were additional data can be pushed (updating
136 its value as needed). */
138 static struct value *
139 value_arg_coerce (struct gdbarch *gdbarch, struct value *arg,
140 struct type *param_type, int is_prototyped, CORE_ADDR *sp)
142 const struct builtin_type *builtin = builtin_type (gdbarch);
143 struct type *arg_type = check_typedef (value_type (arg));
145 = param_type ? check_typedef (param_type) : arg_type;
147 /* Perform any Ada-specific coercion first. */
148 if (current_language->la_language == language_ada)
149 arg = ada_convert_actual (arg, type);
151 /* Force the value to the target if we will need its address. At
152 this point, we could allocate arguments on the stack instead of
153 calling malloc if we knew that their addresses would not be
154 saved by the called function. */
155 arg = value_coerce_to_target (arg);
157 switch (TYPE_CODE (type))
161 struct value *new_value;
163 if (TYPE_CODE (arg_type) == TYPE_CODE_REF)
164 return value_cast_pointers (type, arg, 0);
166 /* Cast the value to the reference's target type, and then
167 convert it back to a reference. This will issue an error
168 if the value was not previously in memory - in some cases
169 we should clearly be allowing this, but how? */
170 new_value = value_cast (TYPE_TARGET_TYPE (type), arg);
171 new_value = value_ref (new_value);
178 /* If we don't have a prototype, coerce to integer type if necessary. */
181 if (TYPE_LENGTH (type) < TYPE_LENGTH (builtin->builtin_int))
182 type = builtin->builtin_int;
184 /* Currently all target ABIs require at least the width of an integer
185 type for an argument. We may have to conditionalize the following
186 type coercion for future targets. */
187 if (TYPE_LENGTH (type) < TYPE_LENGTH (builtin->builtin_int))
188 type = builtin->builtin_int;
191 if (!is_prototyped && coerce_float_to_double_p)
193 if (TYPE_LENGTH (type) < TYPE_LENGTH (builtin->builtin_double))
194 type = builtin->builtin_double;
195 else if (TYPE_LENGTH (type) > TYPE_LENGTH (builtin->builtin_double))
196 type = builtin->builtin_long_double;
200 type = lookup_pointer_type (type);
202 case TYPE_CODE_ARRAY:
203 /* Arrays are coerced to pointers to their first element, unless
204 they are vectors, in which case we want to leave them alone,
205 because they are passed by value. */
206 if (current_language->c_style_arrays)
207 if (!TYPE_VECTOR (type))
208 type = lookup_pointer_type (TYPE_TARGET_TYPE (type));
210 case TYPE_CODE_UNDEF:
212 case TYPE_CODE_STRUCT:
213 case TYPE_CODE_UNION:
216 case TYPE_CODE_RANGE:
217 case TYPE_CODE_STRING:
218 case TYPE_CODE_ERROR:
219 case TYPE_CODE_MEMBERPTR:
220 case TYPE_CODE_METHODPTR:
221 case TYPE_CODE_METHOD:
222 case TYPE_CODE_COMPLEX:
227 return value_cast (type, arg);
230 /* Return the return type of a function with its first instruction exactly at
231 the PC address. Return NULL otherwise. */
234 find_function_return_type (CORE_ADDR pc)
236 struct symbol *sym = find_pc_function (pc);
238 if (sym != NULL && BLOCK_START (SYMBOL_BLOCK_VALUE (sym)) == pc
239 && SYMBOL_TYPE (sym) != NULL)
240 return TYPE_TARGET_TYPE (SYMBOL_TYPE (sym));
245 /* Determine a function's address and its return type from its value.
246 Calls error() if the function is not valid for calling. */
249 find_function_addr (struct value *function, struct type **retval_type)
251 struct type *ftype = check_typedef (value_type (function));
252 struct gdbarch *gdbarch = get_type_arch (ftype);
253 struct type *value_type = NULL;
254 /* Initialize it just to avoid a GCC false warning. */
255 CORE_ADDR funaddr = 0;
257 /* If it's a member function, just look at the function
260 /* Determine address to call. */
261 if (TYPE_CODE (ftype) == TYPE_CODE_FUNC
262 || TYPE_CODE (ftype) == TYPE_CODE_METHOD)
263 funaddr = value_address (function);
264 else if (TYPE_CODE (ftype) == TYPE_CODE_PTR)
266 funaddr = value_as_address (function);
267 ftype = check_typedef (TYPE_TARGET_TYPE (ftype));
268 if (TYPE_CODE (ftype) == TYPE_CODE_FUNC
269 || TYPE_CODE (ftype) == TYPE_CODE_METHOD)
270 funaddr = gdbarch_convert_from_func_ptr_addr (gdbarch, funaddr,
273 if (TYPE_CODE (ftype) == TYPE_CODE_FUNC
274 || TYPE_CODE (ftype) == TYPE_CODE_METHOD)
276 value_type = TYPE_TARGET_TYPE (ftype);
278 if (TYPE_GNU_IFUNC (ftype))
280 funaddr = gnu_ifunc_resolve_addr (gdbarch, funaddr);
282 /* Skip querying the function symbol if no RETVAL_TYPE has been
285 value_type = find_function_return_type (funaddr);
288 else if (TYPE_CODE (ftype) == TYPE_CODE_INT)
290 /* Handle the case of functions lacking debugging info.
291 Their values are characters since their addresses are char. */
292 if (TYPE_LENGTH (ftype) == 1)
293 funaddr = value_as_address (value_addr (function));
296 /* Handle function descriptors lacking debug info. */
297 int found_descriptor = 0;
299 funaddr = 0; /* pacify "gcc -Werror" */
300 if (VALUE_LVAL (function) == lval_memory)
304 funaddr = value_as_address (value_addr (function));
306 funaddr = gdbarch_convert_from_func_ptr_addr (gdbarch, funaddr,
308 if (funaddr != nfunaddr)
309 found_descriptor = 1;
311 if (!found_descriptor)
312 /* Handle integer used as address of a function. */
313 funaddr = (CORE_ADDR) value_as_long (function);
317 error (_("Invalid data type for function to be called."));
319 if (retval_type != NULL)
320 *retval_type = value_type;
321 return funaddr + gdbarch_deprecated_function_start_offset (gdbarch);
324 /* For CALL_DUMMY_ON_STACK, push a breakpoint sequence that the called
325 function returns to. */
328 push_dummy_code (struct gdbarch *gdbarch,
329 CORE_ADDR sp, CORE_ADDR funaddr,
330 struct value **args, int nargs,
331 struct type *value_type,
332 CORE_ADDR *real_pc, CORE_ADDR *bp_addr,
333 struct regcache *regcache)
335 gdb_assert (gdbarch_push_dummy_code_p (gdbarch));
337 return gdbarch_push_dummy_code (gdbarch, sp, funaddr,
338 args, nargs, value_type, real_pc, bp_addr,
342 /* Fetch the name of the function at FUNADDR.
343 This is used in printing an error message for call_function_by_hand.
344 BUF is used to print FUNADDR in hex if the function name cannot be
345 determined. It must be large enough to hold formatted result of
346 RAW_FUNCTION_ADDRESS_FORMAT. */
349 get_function_name (CORE_ADDR funaddr, char *buf, int buf_size)
352 struct symbol *symbol = find_pc_function (funaddr);
355 return SYMBOL_PRINT_NAME (symbol);
359 /* Try the minimal symbols. */
360 struct bound_minimal_symbol msymbol = lookup_minimal_symbol_by_pc (funaddr);
363 return MSYMBOL_PRINT_NAME (msymbol.minsym);
367 char *tmp = xstrprintf (_(RAW_FUNCTION_ADDRESS_FORMAT),
368 hex_string (funaddr));
370 gdb_assert (strlen (tmp) + 1 <= buf_size);
377 /* Subroutine of call_function_by_hand to simplify it.
378 Start up the inferior and wait for it to stop.
379 Return the exception if there's an error, or an exception with
380 reason >= 0 if there's no error.
382 This is done inside a TRY_CATCH so the caller needn't worry about
383 thrown errors. The caller should rethrow if there's an error. */
385 static struct gdb_exception
386 run_inferior_call (struct thread_info *call_thread, CORE_ADDR real_pc)
388 volatile struct gdb_exception e;
389 int saved_in_infcall = call_thread->control.in_infcall;
390 ptid_t call_thread_ptid = call_thread->ptid;
391 int saved_sync_execution = sync_execution;
393 /* Infcalls run synchronously, in the foreground. */
394 if (target_can_async_p ())
397 call_thread->control.in_infcall = 1;
399 clear_proceed_status ();
401 disable_watchpoints_before_interactive_call_start ();
403 /* We want stop_registers, please... */
404 call_thread->control.proceed_to_finish = 1;
406 TRY_CATCH (e, RETURN_MASK_ALL)
408 int was_sync = sync_execution;
410 proceed (real_pc, GDB_SIGNAL_0, 0);
412 /* Inferior function calls are always synchronous, even if the
413 target supports asynchronous execution. Do here what
414 `proceed' itself does in sync mode. */
415 if (target_can_async_p ())
417 wait_for_inferior ();
419 /* If GDB was previously in sync execution mode, then ensure
420 that it remains so. normal_stop calls
421 async_enable_stdin, so reset it again here. In other
422 cases, stdin will be re-enabled by
423 inferior_event_handler, when an exception is thrown. */
425 async_disable_stdin ();
429 /* At this point the current thread may have changed. Refresh
430 CALL_THREAD as it could be invalid if its thread has exited. */
431 call_thread = find_thread_ptid (call_thread_ptid);
433 enable_watchpoints_after_interactive_call_stop ();
435 /* Call breakpoint_auto_delete on the current contents of the bpstat
436 of inferior call thread.
437 If all error()s out of proceed ended up calling normal_stop
438 (and perhaps they should; it already does in the special case
439 of error out of resume()), then we wouldn't need this. */
442 if (call_thread != NULL)
443 breakpoint_auto_delete (call_thread->control.stop_bpstat);
446 if (call_thread != NULL)
447 call_thread->control.in_infcall = saved_in_infcall;
449 sync_execution = saved_sync_execution;
454 /* A cleanup function that calls delete_std_terminate_breakpoint. */
456 cleanup_delete_std_terminate_breakpoint (void *ignore)
458 delete_std_terminate_breakpoint ();
461 /* All this stuff with a dummy frame may seem unnecessarily complicated
462 (why not just save registers in GDB?). The purpose of pushing a dummy
463 frame which looks just like a real frame is so that if you call a
464 function and then hit a breakpoint (get a signal, etc), "backtrace"
465 will look right. Whether the backtrace needs to actually show the
466 stack at the time the inferior function was called is debatable, but
467 it certainly needs to not display garbage. So if you are contemplating
468 making dummy frames be different from normal frames, consider that. */
470 /* Perform a function call in the inferior.
471 ARGS is a vector of values of arguments (NARGS of them).
472 FUNCTION is a value, the function to be called.
473 Returns a value representing what the function returned.
474 May fail to return, if a breakpoint or signal is hit
475 during the execution of the function.
477 ARGS is modified to contain coerced values. */
480 call_function_by_hand (struct value *function, int nargs, struct value **args)
483 struct type *values_type, *target_values_type;
484 unsigned char struct_return = 0, hidden_first_param_p = 0;
485 CORE_ADDR struct_addr = 0;
486 struct infcall_control_state *inf_status;
487 struct cleanup *inf_status_cleanup;
488 struct infcall_suspend_state *caller_state;
491 struct type *ftype = check_typedef (value_type (function));
493 struct frame_id dummy_id;
494 struct cleanup *args_cleanup;
495 struct frame_info *frame;
496 struct gdbarch *gdbarch;
497 struct cleanup *terminate_bp_cleanup;
498 ptid_t call_thread_ptid;
499 struct gdb_exception e;
500 char name_buf[RAW_FUNCTION_ADDRESS_SIZE];
502 if (TYPE_CODE (ftype) == TYPE_CODE_PTR)
503 ftype = check_typedef (TYPE_TARGET_TYPE (ftype));
505 if (!target_has_execution)
508 if (get_traceframe_number () >= 0)
509 error (_("May not call functions while looking at trace frames."));
511 if (execution_direction == EXEC_REVERSE)
512 error (_("Cannot call functions in reverse mode."));
514 frame = get_current_frame ();
515 gdbarch = get_frame_arch (frame);
517 if (!gdbarch_push_dummy_call_p (gdbarch))
518 error (_("This target does not support function calls."));
520 /* A cleanup for the inferior status.
521 This is only needed while we're preparing the inferior function call. */
522 inf_status = save_infcall_control_state ();
524 = make_cleanup_restore_infcall_control_state (inf_status);
526 /* Save the caller's registers and other state associated with the
527 inferior itself so that they can be restored once the
528 callee returns. To allow nested calls the registers are (further
529 down) pushed onto a dummy frame stack. Include a cleanup (which
530 is tossed once the regcache has been pushed). */
531 caller_state = save_infcall_suspend_state ();
532 make_cleanup_restore_infcall_suspend_state (caller_state);
534 /* Ensure that the initial SP is correctly aligned. */
536 CORE_ADDR old_sp = get_frame_sp (frame);
538 if (gdbarch_frame_align_p (gdbarch))
540 sp = gdbarch_frame_align (gdbarch, old_sp);
541 /* NOTE: cagney/2003-08-13: Skip the "red zone". For some
542 ABIs, a function can use memory beyond the inner most stack
543 address. AMD64 called that region the "red zone". Skip at
544 least the "red zone" size before allocating any space on
546 if (gdbarch_inner_than (gdbarch, 1, 2))
547 sp -= gdbarch_frame_red_zone_size (gdbarch);
549 sp += gdbarch_frame_red_zone_size (gdbarch);
551 gdb_assert (sp == gdbarch_frame_align (gdbarch, sp));
552 /* NOTE: cagney/2002-09-18:
554 On a RISC architecture, a void parameterless generic dummy
555 frame (i.e., no parameters, no result) typically does not
556 need to push anything the stack and hence can leave SP and
557 FP. Similarly, a frameless (possibly leaf) function does
558 not push anything on the stack and, hence, that too can
559 leave FP and SP unchanged. As a consequence, a sequence of
560 void parameterless generic dummy frame calls to frameless
561 functions will create a sequence of effectively identical
562 frames (SP, FP and TOS and PC the same). This, not
563 suprisingly, results in what appears to be a stack in an
564 infinite loop --- when GDB tries to find a generic dummy
565 frame on the internal dummy frame stack, it will always
568 To avoid this problem, the code below always grows the
569 stack. That way, two dummy frames can never be identical.
570 It does burn a few bytes of stack but that is a small price
574 if (gdbarch_inner_than (gdbarch, 1, 2))
575 /* Stack grows down. */
576 sp = gdbarch_frame_align (gdbarch, old_sp - 1);
578 /* Stack grows up. */
579 sp = gdbarch_frame_align (gdbarch, old_sp + 1);
581 /* SP may have underflown address zero here from OLD_SP. Memory access
582 functions will probably fail in such case but that is a target's
586 /* FIXME: cagney/2002-09-18: Hey, you loose!
588 Who knows how badly aligned the SP is!
590 If the generic dummy frame ends up empty (because nothing is
591 pushed) GDB won't be able to correctly perform back traces.
592 If a target is having trouble with backtraces, first thing to
593 do is add FRAME_ALIGN() to the architecture vector. If that
594 fails, try dummy_id().
596 If the ABI specifies a "Red Zone" (see the doco) the code
597 below will quietly trash it. */
601 funaddr = find_function_addr (function, &values_type);
603 values_type = builtin_type (gdbarch)->builtin_int;
605 CHECK_TYPEDEF (values_type);
607 /* Are we returning a value using a structure return (passing a
608 hidden argument pointing to storage) or a normal value return?
609 There are two cases: language-mandated structure return and
610 target ABI structure return. The variable STRUCT_RETURN only
611 describes the latter. The language version is handled by passing
612 the return location as the first parameter to the function,
613 even preceding "this". This is different from the target
614 ABI version, which is target-specific; for instance, on ia64
615 the first argument is passed in out0 but the hidden structure
616 return pointer would normally be passed in r8. */
618 if (gdbarch_return_in_first_hidden_param_p (gdbarch, values_type))
620 hidden_first_param_p = 1;
622 /* Tell the target specific argument pushing routine not to
624 target_values_type = builtin_type (gdbarch)->builtin_void;
628 struct_return = using_struct_return (gdbarch, function, values_type);
629 target_values_type = values_type;
632 /* Determine the location of the breakpoint (and possibly other
633 stuff) that the called function will return to. The SPARC, for a
634 function returning a structure or union, needs to make space for
635 not just the breakpoint but also an extra word containing the
636 size (?) of the structure being passed. */
638 switch (gdbarch_call_dummy_location (gdbarch))
642 const gdb_byte *bp_bytes;
643 CORE_ADDR bp_addr_as_address;
646 /* Be careful BP_ADDR is in inferior PC encoding while
647 BP_ADDR_AS_ADDRESS is a plain memory address. */
649 sp = push_dummy_code (gdbarch, sp, funaddr, args, nargs,
650 target_values_type, &real_pc, &bp_addr,
651 get_current_regcache ());
653 /* Write a legitimate instruction at the point where the infcall
654 breakpoint is going to be inserted. While this instruction
655 is never going to be executed, a user investigating the
656 memory from GDB would see this instruction instead of random
657 uninitialized bytes. We chose the breakpoint instruction
658 as it may look as the most logical one to the user and also
659 valgrind 3.7.0 needs it for proper vgdb inferior calls.
661 If software breakpoints are unsupported for this target we
662 leave the user visible memory content uninitialized. */
664 bp_addr_as_address = bp_addr;
665 bp_bytes = gdbarch_breakpoint_from_pc (gdbarch, &bp_addr_as_address,
667 if (bp_bytes != NULL)
668 write_memory (bp_addr_as_address, bp_bytes, bp_size);
673 CORE_ADDR dummy_addr;
676 dummy_addr = entry_point_address ();
678 /* A call dummy always consists of just a single breakpoint, so
679 its address is the same as the address of the dummy.
681 The actual breakpoint is inserted separatly so there is no need to
683 bp_addr = dummy_addr;
687 internal_error (__FILE__, __LINE__, _("bad switch"));
690 if (nargs < TYPE_NFIELDS (ftype))
691 error (_("Too few arguments in function call."));
696 for (i = nargs - 1; i >= 0; i--)
699 struct type *param_type;
701 /* FIXME drow/2002-05-31: Should just always mark methods as
702 prototyped. Can we respect TYPE_VARARGS? Probably not. */
703 if (TYPE_CODE (ftype) == TYPE_CODE_METHOD)
705 else if (i < TYPE_NFIELDS (ftype))
706 prototyped = TYPE_PROTOTYPED (ftype);
710 if (i < TYPE_NFIELDS (ftype))
711 param_type = TYPE_FIELD_TYPE (ftype, i);
715 args[i] = value_arg_coerce (gdbarch, args[i],
716 param_type, prototyped, &sp);
718 if (param_type != NULL && language_pass_by_reference (param_type))
719 args[i] = value_addr (args[i]);
723 /* Reserve space for the return structure to be written on the
724 stack, if necessary. Make certain that the value is correctly
727 if (struct_return || hidden_first_param_p)
729 if (gdbarch_inner_than (gdbarch, 1, 2))
731 /* Stack grows downward. Align STRUCT_ADDR and SP after
732 making space for the return value. */
733 sp -= TYPE_LENGTH (values_type);
734 if (gdbarch_frame_align_p (gdbarch))
735 sp = gdbarch_frame_align (gdbarch, sp);
740 /* Stack grows upward. Align the frame, allocate space, and
741 then again, re-align the frame??? */
742 if (gdbarch_frame_align_p (gdbarch))
743 sp = gdbarch_frame_align (gdbarch, sp);
745 sp += TYPE_LENGTH (values_type);
746 if (gdbarch_frame_align_p (gdbarch))
747 sp = gdbarch_frame_align (gdbarch, sp);
751 if (hidden_first_param_p)
753 struct value **new_args;
755 /* Add the new argument to the front of the argument list. */
756 new_args = xmalloc (sizeof (struct value *) * (nargs + 1));
757 new_args[0] = value_from_pointer (lookup_pointer_type (values_type),
759 memcpy (&new_args[1], &args[0], sizeof (struct value *) * nargs);
762 args_cleanup = make_cleanup (xfree, args);
765 args_cleanup = make_cleanup (null_cleanup, NULL);
767 /* Create the dummy stack frame. Pass in the call dummy address as,
768 presumably, the ABI code knows where, in the call dummy, the
769 return address should be pointed. */
770 sp = gdbarch_push_dummy_call (gdbarch, function, get_current_regcache (),
771 bp_addr, nargs, args,
772 sp, struct_return, struct_addr);
774 do_cleanups (args_cleanup);
776 /* Set up a frame ID for the dummy frame so we can pass it to
777 set_momentary_breakpoint. We need to give the breakpoint a frame
778 ID so that the breakpoint code can correctly re-identify the
780 /* Sanity. The exact same SP value is returned by PUSH_DUMMY_CALL,
781 saved as the dummy-frame TOS, and used by dummy_id to form
782 the frame ID's stack address. */
783 dummy_id = frame_id_build (sp, bp_addr);
785 /* Create a momentary breakpoint at the return address of the
786 inferior. That way it breaks when it returns. */
789 struct breakpoint *bpt, *longjmp_b;
790 struct symtab_and_line sal;
792 init_sal (&sal); /* initialize to zeroes */
793 sal.pspace = current_program_space;
795 sal.section = find_pc_overlay (sal.pc);
796 /* Sanity. The exact same SP value is returned by
797 PUSH_DUMMY_CALL, saved as the dummy-frame TOS, and used by
798 dummy_id to form the frame ID's stack address. */
799 bpt = set_momentary_breakpoint (gdbarch, sal, dummy_id, bp_call_dummy);
801 /* set_momentary_breakpoint invalidates FRAME. */
804 bpt->disposition = disp_del;
805 gdb_assert (bpt->related_breakpoint == bpt);
807 longjmp_b = set_longjmp_breakpoint_for_call_dummy ();
810 /* Link BPT into the chain of LONGJMP_B. */
811 bpt->related_breakpoint = longjmp_b;
812 while (longjmp_b->related_breakpoint != bpt->related_breakpoint)
813 longjmp_b = longjmp_b->related_breakpoint;
814 longjmp_b->related_breakpoint = bpt;
818 /* Create a breakpoint in std::terminate.
819 If a C++ exception is raised in the dummy-frame, and the
820 exception handler is (normally, and expected to be) out-of-frame,
821 the default C++ handler will (wrongly) be called in an inferior
822 function call. This is wrong, as an exception can be normally
823 and legally handled out-of-frame. The confines of the dummy frame
824 prevent the unwinder from finding the correct handler (or any
825 handler, unless it is in-frame). The default handler calls
826 std::terminate. This will kill the inferior. Assert that
827 terminate should never be called in an inferior function
828 call. Place a momentary breakpoint in the std::terminate function
829 and if triggered in the call, rewind. */
830 if (unwind_on_terminating_exception_p)
831 set_std_terminate_breakpoint ();
833 /* Everything's ready, push all the info needed to restore the
834 caller (and identify the dummy-frame) onto the dummy-frame
836 dummy_frame_push (caller_state, &dummy_id, inferior_ptid);
838 /* Discard both inf_status and caller_state cleanups.
839 From this point on we explicitly restore the associated state
841 discard_cleanups (inf_status_cleanup);
843 /* Register a clean-up for unwind_on_terminating_exception_breakpoint. */
844 terminate_bp_cleanup = make_cleanup (cleanup_delete_std_terminate_breakpoint,
847 /* - SNIP - SNIP - SNIP - SNIP - SNIP - SNIP - SNIP - SNIP - SNIP -
848 If you're looking to implement asynchronous dummy-frames, then
849 just below is the place to chop this function in two.. */
851 /* TP is invalid after run_inferior_call returns, so enclose this
852 in a block so that it's only in scope during the time it's valid. */
854 struct thread_info *tp = inferior_thread ();
856 /* Save this thread's ptid, we need it later but the thread
858 call_thread_ptid = tp->ptid;
860 /* Run the inferior until it stops. */
862 e = run_inferior_call (tp, real_pc);
865 /* Rethrow an error if we got one trying to run the inferior. */
869 const char *name = get_function_name (funaddr,
870 name_buf, sizeof (name_buf));
872 discard_infcall_control_state (inf_status);
874 /* We could discard the dummy frame here if the program exited,
875 but it will get garbage collected the next time the program is
881 throw_error (e.error, _("%s\n\
882 An error occurred while in a function called from GDB.\n\
883 Evaluation of the expression containing the function\n\
884 (%s) will be abandoned.\n\
885 When the function is done executing, GDB will silently stop."),
893 /* If the program has exited, or we stopped at a different thread,
894 exit and inform the user. */
896 if (! target_has_execution)
898 const char *name = get_function_name (funaddr,
899 name_buf, sizeof (name_buf));
901 /* If we try to restore the inferior status,
902 we'll crash as the inferior is no longer running. */
903 discard_infcall_control_state (inf_status);
905 /* We could discard the dummy frame here given that the program exited,
906 but it will get garbage collected the next time the program is
909 error (_("The program being debugged exited while in a function "
911 "Evaluation of the expression containing the function\n"
912 "(%s) will be abandoned."),
916 if (! ptid_equal (call_thread_ptid, inferior_ptid))
918 const char *name = get_function_name (funaddr,
919 name_buf, sizeof (name_buf));
921 /* We've switched threads. This can happen if another thread gets a
922 signal or breakpoint while our thread was running.
923 There's no point in restoring the inferior status,
924 we're in a different thread. */
925 discard_infcall_control_state (inf_status);
926 /* Keep the dummy frame record, if the user switches back to the
927 thread with the hand-call, we'll need it. */
928 if (stopped_by_random_signal)
930 The program received a signal in another thread while\n\
931 making a function call from GDB.\n\
932 Evaluation of the expression containing the function\n\
933 (%s) will be abandoned.\n\
934 When the function is done executing, GDB will silently stop."),
938 The program stopped in another thread while making a function call from GDB.\n\
939 Evaluation of the expression containing the function\n\
940 (%s) will be abandoned.\n\
941 When the function is done executing, GDB will silently stop."),
945 if (stopped_by_random_signal || stop_stack_dummy != STOP_STACK_DUMMY)
947 const char *name = get_function_name (funaddr,
948 name_buf, sizeof (name_buf));
950 if (stopped_by_random_signal)
952 /* We stopped inside the FUNCTION because of a random
953 signal. Further execution of the FUNCTION is not
956 if (unwind_on_signal_p)
958 /* The user wants the context restored. */
960 /* We must get back to the frame we were before the
962 dummy_frame_pop (dummy_id, call_thread_ptid);
964 /* We also need to restore inferior status to that before the
966 restore_infcall_control_state (inf_status);
968 /* FIXME: Insert a bunch of wrap_here; name can be very
969 long if it's a C++ name with arguments and stuff. */
971 The program being debugged was signaled while in a function called from GDB.\n\
972 GDB has restored the context to what it was before the call.\n\
973 To change this behavior use \"set unwindonsignal off\".\n\
974 Evaluation of the expression containing the function\n\
975 (%s) will be abandoned."),
980 /* The user wants to stay in the frame where we stopped
982 Discard inferior status, we're not at the same point
984 discard_infcall_control_state (inf_status);
986 /* FIXME: Insert a bunch of wrap_here; name can be very
987 long if it's a C++ name with arguments and stuff. */
989 The program being debugged was signaled while in a function called from GDB.\n\
990 GDB remains in the frame where the signal was received.\n\
991 To change this behavior use \"set unwindonsignal on\".\n\
992 Evaluation of the expression containing the function\n\
993 (%s) will be abandoned.\n\
994 When the function is done executing, GDB will silently stop."),
999 if (stop_stack_dummy == STOP_STD_TERMINATE)
1001 /* We must get back to the frame we were before the dummy
1003 dummy_frame_pop (dummy_id, call_thread_ptid);
1005 /* We also need to restore inferior status to that before
1007 restore_infcall_control_state (inf_status);
1010 The program being debugged entered a std::terminate call, most likely\n\
1011 caused by an unhandled C++ exception. GDB blocked this call in order\n\
1012 to prevent the program from being terminated, and has restored the\n\
1013 context to its original state before the call.\n\
1014 To change this behaviour use \"set unwind-on-terminating-exception off\".\n\
1015 Evaluation of the expression containing the function (%s)\n\
1016 will be abandoned."),
1019 else if (stop_stack_dummy == STOP_NONE)
1022 /* We hit a breakpoint inside the FUNCTION.
1023 Keep the dummy frame, the user may want to examine its state.
1024 Discard inferior status, we're not at the same point
1026 discard_infcall_control_state (inf_status);
1028 /* The following error message used to say "The expression
1029 which contained the function call has been discarded."
1030 It is a hard concept to explain in a few words. Ideally,
1031 GDB would be able to resume evaluation of the expression
1032 when the function finally is done executing. Perhaps
1033 someday this will be implemented (it would not be easy). */
1034 /* FIXME: Insert a bunch of wrap_here; name can be very long if it's
1035 a C++ name with arguments and stuff. */
1037 The program being debugged stopped while in a function called from GDB.\n\
1038 Evaluation of the expression containing the function\n\
1039 (%s) will be abandoned.\n\
1040 When the function is done executing, GDB will silently stop."),
1044 /* The above code errors out, so ... */
1045 internal_error (__FILE__, __LINE__, _("... should not be here"));
1048 do_cleanups (terminate_bp_cleanup);
1050 /* If we get here the called FUNCTION ran to completion,
1051 and the dummy frame has already been popped. */
1054 struct address_space *aspace = get_regcache_aspace (stop_registers);
1055 struct regcache *retbuf = regcache_xmalloc (gdbarch, aspace);
1056 struct cleanup *retbuf_cleanup = make_cleanup_regcache_xfree (retbuf);
1057 struct value *retval = NULL;
1059 regcache_cpy_no_passthrough (retbuf, stop_registers);
1061 /* Inferior call is successful. Restore the inferior status.
1062 At this stage, leave the RETBUF alone. */
1063 restore_infcall_control_state (inf_status);
1065 /* Figure out the value returned by the function. */
1066 retval = allocate_value (values_type);
1068 if (hidden_first_param_p)
1069 read_value_memory (retval, 0, 1, struct_addr,
1070 value_contents_raw (retval),
1071 TYPE_LENGTH (values_type));
1072 else if (TYPE_CODE (target_values_type) != TYPE_CODE_VOID)
1074 /* If the function returns void, don't bother fetching the
1076 switch (gdbarch_return_value (gdbarch, function, target_values_type,
1079 case RETURN_VALUE_REGISTER_CONVENTION:
1080 case RETURN_VALUE_ABI_RETURNS_ADDRESS:
1081 case RETURN_VALUE_ABI_PRESERVES_ADDRESS:
1082 gdbarch_return_value (gdbarch, function, values_type,
1083 retbuf, value_contents_raw (retval), NULL);
1085 case RETURN_VALUE_STRUCT_CONVENTION:
1086 read_value_memory (retval, 0, 1, struct_addr,
1087 value_contents_raw (retval),
1088 TYPE_LENGTH (values_type));
1093 do_cleanups (retbuf_cleanup);
1095 gdb_assert (retval);
1101 /* Provide a prototype to silence -Wmissing-prototypes. */
1102 void _initialize_infcall (void);
1105 _initialize_infcall (void)
1107 add_setshow_boolean_cmd ("coerce-float-to-double", class_obscure,
1108 &coerce_float_to_double_p, _("\
1109 Set coercion of floats to doubles when calling functions."), _("\
1110 Show coercion of floats to doubles when calling functions"), _("\
1111 Variables of type float should generally be converted to doubles before\n\
1112 calling an unprototyped function, and left alone when calling a prototyped\n\
1113 function. However, some older debug info formats do not provide enough\n\
1114 information to determine that a function is prototyped. If this flag is\n\
1115 set, GDB will perform the conversion for a function it considers\n\
1117 The default is to perform the conversion.\n"),
1119 show_coerce_float_to_double_p,
1120 &setlist, &showlist);
1122 add_setshow_boolean_cmd ("unwindonsignal", no_class,
1123 &unwind_on_signal_p, _("\
1124 Set unwinding of stack if a signal is received while in a call dummy."), _("\
1125 Show unwinding of stack if a signal is received while in a call dummy."), _("\
1126 The unwindonsignal lets the user determine what gdb should do if a signal\n\
1127 is received while in a function called from gdb (call dummy). If set, gdb\n\
1128 unwinds the stack and restore the context to what as it was before the call.\n\
1129 The default is to stop in the frame where the signal was received."),
1131 show_unwind_on_signal_p,
1132 &setlist, &showlist);
1134 add_setshow_boolean_cmd ("unwind-on-terminating-exception", no_class,
1135 &unwind_on_terminating_exception_p, _("\
1136 Set unwinding of stack if std::terminate is called while in call dummy."), _("\
1137 Show unwinding of stack if std::terminate() is called while in a call dummy."),
1139 The unwind on terminating exception flag lets the user determine\n\
1140 what gdb should do if a std::terminate() call is made from the\n\
1141 default exception handler. If set, gdb unwinds the stack and restores\n\
1142 the context to what it was before the call. If unset, gdb allows the\n\
1143 std::terminate call to proceed.\n\
1144 The default is to unwind the frame."),
1146 show_unwind_on_terminating_exception_p,
1147 &setlist, &showlist);