1 /* Perform an inferior function call, for GDB, the GNU debugger.
3 Copyright (C) 1986-2018 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/>. */
22 #include "breakpoint.h"
23 #include "tracepoint.h"
34 #include "dummy-frame.h"
36 #include "gdbthread.h"
37 #include "event-top.h"
38 #include "observable.h"
41 #include "thread-fsm.h"
44 /* If we can't find a function's name from its address,
45 we print this instead. */
46 #define RAW_FUNCTION_ADDRESS_FORMAT "at 0x%s"
47 #define RAW_FUNCTION_ADDRESS_SIZE (sizeof (RAW_FUNCTION_ADDRESS_FORMAT) \
48 + 2 * sizeof (CORE_ADDR))
50 /* NOTE: cagney/2003-04-16: What's the future of this code?
52 GDB needs an asynchronous expression evaluator, that means an
53 asynchronous inferior function call implementation, and that in
54 turn means restructuring the code so that it is event driven. */
56 /* How you should pass arguments to a function depends on whether it
57 was defined in K&R style or prototype style. If you define a
58 function using the K&R syntax that takes a `float' argument, then
59 callers must pass that argument as a `double'. If you define the
60 function using the prototype syntax, then you must pass the
61 argument as a `float', with no promotion.
63 Unfortunately, on certain older platforms, the debug info doesn't
64 indicate reliably how each function was defined. A function type's
65 TYPE_PROTOTYPED flag may be clear, even if the function was defined
66 in prototype style. When calling a function whose TYPE_PROTOTYPED
67 flag is clear, GDB consults this flag to decide what to do.
69 For modern targets, it is proper to assume that, if the prototype
70 flag is clear, that can be trusted: `float' arguments should be
71 promoted to `double'. For some older targets, if the prototype
72 flag is clear, that doesn't tell us anything. The default is to
73 trust the debug information; the user can override this behavior
74 with "set coerce-float-to-double 0". */
76 static int coerce_float_to_double_p
= 1;
78 show_coerce_float_to_double_p (struct ui_file
*file
, int from_tty
,
79 struct cmd_list_element
*c
, const char *value
)
81 fprintf_filtered (file
,
82 _("Coercion of floats to doubles "
83 "when calling functions is %s.\n"),
87 /* This boolean tells what gdb should do if a signal is received while
88 in a function called from gdb (call dummy). If set, gdb unwinds
89 the stack and restore the context to what as it was before the
92 The default is to stop in the frame where the signal was received. */
94 static int unwind_on_signal_p
= 0;
96 show_unwind_on_signal_p (struct ui_file
*file
, int from_tty
,
97 struct cmd_list_element
*c
, const char *value
)
99 fprintf_filtered (file
,
100 _("Unwinding of stack if a signal is "
101 "received while in a call dummy is %s.\n"),
105 /* This boolean tells what gdb should do if a std::terminate call is
106 made while in a function called from gdb (call dummy).
107 As the confines of a single dummy stack prohibit out-of-frame
108 handlers from handling a raised exception, and as out-of-frame
109 handlers are common in C++, this can lead to no handler being found
110 by the unwinder, and a std::terminate call. This is a false positive.
111 If set, gdb unwinds the stack and restores the context to what it
114 The default is to unwind the frame if a std::terminate call is
117 static int unwind_on_terminating_exception_p
= 1;
120 show_unwind_on_terminating_exception_p (struct ui_file
*file
, int from_tty
,
121 struct cmd_list_element
*c
,
125 fprintf_filtered (file
,
126 _("Unwind stack if a C++ exception is "
127 "unhandled while in a call dummy is %s.\n"),
131 /* Perform the standard coercions that are specified
132 for arguments to be passed to C or Ada functions.
134 If PARAM_TYPE is non-NULL, it is the expected parameter type.
135 IS_PROTOTYPED is non-zero if the function declaration is prototyped.
136 SP is the stack pointer were additional data can be pushed (updating
137 its value as needed). */
139 static struct value
*
140 value_arg_coerce (struct gdbarch
*gdbarch
, struct value
*arg
,
141 struct type
*param_type
, int is_prototyped
, CORE_ADDR
*sp
)
143 const struct builtin_type
*builtin
= builtin_type (gdbarch
);
144 struct type
*arg_type
= check_typedef (value_type (arg
));
146 = param_type
? check_typedef (param_type
) : arg_type
;
148 /* Perform any Ada-specific coercion first. */
149 if (current_language
->la_language
== language_ada
)
150 arg
= ada_convert_actual (arg
, type
);
152 /* Force the value to the target if we will need its address. At
153 this point, we could allocate arguments on the stack instead of
154 calling malloc if we knew that their addresses would not be
155 saved by the called function. */
156 arg
= value_coerce_to_target (arg
);
158 switch (TYPE_CODE (type
))
161 case TYPE_CODE_RVALUE_REF
:
163 struct value
*new_value
;
165 if (TYPE_IS_REFERENCE (arg_type
))
166 return value_cast_pointers (type
, arg
, 0);
168 /* Cast the value to the reference's target type, and then
169 convert it back to a reference. This will issue an error
170 if the value was not previously in memory - in some cases
171 we should clearly be allowing this, but how? */
172 new_value
= value_cast (TYPE_TARGET_TYPE (type
), arg
);
173 new_value
= value_ref (new_value
, TYPE_CODE (type
));
180 /* If we don't have a prototype, coerce to integer type if necessary. */
183 if (TYPE_LENGTH (type
) < TYPE_LENGTH (builtin
->builtin_int
))
184 type
= builtin
->builtin_int
;
186 /* Currently all target ABIs require at least the width of an integer
187 type for an argument. We may have to conditionalize the following
188 type coercion for future targets. */
189 if (TYPE_LENGTH (type
) < TYPE_LENGTH (builtin
->builtin_int
))
190 type
= builtin
->builtin_int
;
193 if (!is_prototyped
&& coerce_float_to_double_p
)
195 if (TYPE_LENGTH (type
) < TYPE_LENGTH (builtin
->builtin_double
))
196 type
= builtin
->builtin_double
;
197 else if (TYPE_LENGTH (type
) > TYPE_LENGTH (builtin
->builtin_double
))
198 type
= builtin
->builtin_long_double
;
202 type
= lookup_pointer_type (type
);
204 case TYPE_CODE_ARRAY
:
205 /* Arrays are coerced to pointers to their first element, unless
206 they are vectors, in which case we want to leave them alone,
207 because they are passed by value. */
208 if (current_language
->c_style_arrays
)
209 if (!TYPE_VECTOR (type
))
210 type
= lookup_pointer_type (TYPE_TARGET_TYPE (type
));
212 case TYPE_CODE_UNDEF
:
214 case TYPE_CODE_STRUCT
:
215 case TYPE_CODE_UNION
:
218 case TYPE_CODE_RANGE
:
219 case TYPE_CODE_STRING
:
220 case TYPE_CODE_ERROR
:
221 case TYPE_CODE_MEMBERPTR
:
222 case TYPE_CODE_METHODPTR
:
223 case TYPE_CODE_METHOD
:
224 case TYPE_CODE_COMPLEX
:
229 return value_cast (type
, arg
);
235 find_function_addr (struct value
*function
,
236 struct type
**retval_type
,
237 struct type
**function_type
)
239 struct type
*ftype
= check_typedef (value_type (function
));
240 struct gdbarch
*gdbarch
= get_type_arch (ftype
);
241 struct type
*value_type
= NULL
;
242 /* Initialize it just to avoid a GCC false warning. */
243 CORE_ADDR funaddr
= 0;
245 /* If it's a member function, just look at the function
248 /* Determine address to call. */
249 if (TYPE_CODE (ftype
) == TYPE_CODE_FUNC
250 || TYPE_CODE (ftype
) == TYPE_CODE_METHOD
)
251 funaddr
= value_address (function
);
252 else if (TYPE_CODE (ftype
) == TYPE_CODE_PTR
)
254 funaddr
= value_as_address (function
);
255 ftype
= check_typedef (TYPE_TARGET_TYPE (ftype
));
256 if (TYPE_CODE (ftype
) == TYPE_CODE_FUNC
257 || TYPE_CODE (ftype
) == TYPE_CODE_METHOD
)
258 funaddr
= gdbarch_convert_from_func_ptr_addr (gdbarch
, funaddr
,
259 current_top_target ());
261 if (TYPE_CODE (ftype
) == TYPE_CODE_FUNC
262 || TYPE_CODE (ftype
) == TYPE_CODE_METHOD
)
264 if (TYPE_GNU_IFUNC (ftype
))
266 CORE_ADDR resolver_addr
= funaddr
;
268 /* Resolve the ifunc. Note this may call the resolver
269 function in the inferior. */
270 funaddr
= gnu_ifunc_resolve_addr (gdbarch
, resolver_addr
);
272 /* Skip querying the function symbol if no RETVAL_TYPE or
273 FUNCTION_TYPE have been asked for. */
274 if (retval_type
!= NULL
|| function_type
!= NULL
)
276 type
*target_ftype
= find_function_type (funaddr
);
277 /* If we don't have debug info for the target function,
278 see if we can instead extract the target function's
279 type from the type that the resolver returns. */
280 if (target_ftype
== NULL
)
281 target_ftype
= find_gnu_ifunc_target_type (resolver_addr
);
282 if (target_ftype
!= NULL
)
284 value_type
= TYPE_TARGET_TYPE (check_typedef (target_ftype
));
285 ftype
= target_ftype
;
290 value_type
= TYPE_TARGET_TYPE (ftype
);
292 else if (TYPE_CODE (ftype
) == TYPE_CODE_INT
)
294 /* Handle the case of functions lacking debugging info.
295 Their values are characters since their addresses are char. */
296 if (TYPE_LENGTH (ftype
) == 1)
297 funaddr
= value_as_address (value_addr (function
));
300 /* Handle function descriptors lacking debug info. */
301 int found_descriptor
= 0;
303 funaddr
= 0; /* pacify "gcc -Werror" */
304 if (VALUE_LVAL (function
) == lval_memory
)
308 funaddr
= value_as_address (value_addr (function
));
311 = gdbarch_convert_from_func_ptr_addr (gdbarch
, funaddr
,
312 current_top_target ());
313 if (funaddr
!= nfunaddr
)
314 found_descriptor
= 1;
316 if (!found_descriptor
)
317 /* Handle integer used as address of a function. */
318 funaddr
= (CORE_ADDR
) value_as_long (function
);
322 error (_("Invalid data type for function to be called."));
324 if (retval_type
!= NULL
)
325 *retval_type
= value_type
;
326 if (function_type
!= NULL
)
327 *function_type
= ftype
;
328 return funaddr
+ gdbarch_deprecated_function_start_offset (gdbarch
);
331 /* For CALL_DUMMY_ON_STACK, push a breakpoint sequence that the called
332 function returns to. */
335 push_dummy_code (struct gdbarch
*gdbarch
,
336 CORE_ADDR sp
, CORE_ADDR funaddr
,
337 struct value
**args
, int nargs
,
338 struct type
*value_type
,
339 CORE_ADDR
*real_pc
, CORE_ADDR
*bp_addr
,
340 struct regcache
*regcache
)
342 gdb_assert (gdbarch_push_dummy_code_p (gdbarch
));
344 return gdbarch_push_dummy_code (gdbarch
, sp
, funaddr
,
345 args
, nargs
, value_type
, real_pc
, bp_addr
,
352 error_call_unknown_return_type (const char *func_name
)
354 if (func_name
!= NULL
)
355 error (_("'%s' has unknown return type; "
356 "cast the call to its declared return type"),
359 error (_("function has unknown return type; "
360 "cast the call to its declared return type"));
363 /* Fetch the name of the function at FUNADDR.
364 This is used in printing an error message for call_function_by_hand.
365 BUF is used to print FUNADDR in hex if the function name cannot be
366 determined. It must be large enough to hold formatted result of
367 RAW_FUNCTION_ADDRESS_FORMAT. */
370 get_function_name (CORE_ADDR funaddr
, char *buf
, int buf_size
)
373 struct symbol
*symbol
= find_pc_function (funaddr
);
376 return SYMBOL_PRINT_NAME (symbol
);
380 /* Try the minimal symbols. */
381 struct bound_minimal_symbol msymbol
= lookup_minimal_symbol_by_pc (funaddr
);
384 return MSYMBOL_PRINT_NAME (msymbol
.minsym
);
388 std::string tmp
= string_printf (_(RAW_FUNCTION_ADDRESS_FORMAT
),
389 hex_string (funaddr
));
391 gdb_assert (tmp
.length () + 1 <= buf_size
);
392 return strcpy (buf
, tmp
.c_str ());
396 /* All the meta data necessary to extract the call's return value. */
398 struct call_return_meta_info
400 /* The caller frame's architecture. */
401 struct gdbarch
*gdbarch
;
403 /* The called function. */
404 struct value
*function
;
406 /* The return value's type. */
407 struct type
*value_type
;
409 /* Are we returning a value using a structure return or a normal
413 /* If using a structure return, this is the structure's address. */
414 CORE_ADDR struct_addr
;
417 /* Extract the called function's return value. */
419 static struct value
*
420 get_call_return_value (struct call_return_meta_info
*ri
)
422 struct value
*retval
= NULL
;
423 thread_info
*thr
= inferior_thread ();
424 bool stack_temporaries
= thread_stack_temporaries_enabled_p (thr
);
426 if (TYPE_CODE (ri
->value_type
) == TYPE_CODE_VOID
)
427 retval
= allocate_value (ri
->value_type
);
428 else if (ri
->struct_return_p
)
430 if (stack_temporaries
)
432 retval
= value_from_contents_and_address (ri
->value_type
, NULL
,
434 push_thread_stack_temporary (thr
, retval
);
438 retval
= allocate_value (ri
->value_type
);
439 read_value_memory (retval
, 0, 1, ri
->struct_addr
,
440 value_contents_raw (retval
),
441 TYPE_LENGTH (ri
->value_type
));
446 retval
= allocate_value (ri
->value_type
);
447 gdbarch_return_value (ri
->gdbarch
, ri
->function
, ri
->value_type
,
448 get_current_regcache (),
449 value_contents_raw (retval
), NULL
);
450 if (stack_temporaries
&& class_or_union_p (ri
->value_type
))
452 /* Values of class type returned in registers are copied onto
453 the stack and their lval_type set to lval_memory. This is
454 required because further evaluation of the expression
455 could potentially invoke methods on the return value
456 requiring GDB to evaluate the "this" pointer. To evaluate
457 the this pointer, GDB needs the memory address of the
459 value_force_lval (retval
, ri
->struct_addr
);
460 push_thread_stack_temporary (thr
, retval
);
464 gdb_assert (retval
!= NULL
);
468 /* Data for the FSM that manages an infcall. It's main job is to
469 record the called function's return value. */
471 struct call_thread_fsm
473 /* The base class. */
474 struct thread_fsm thread_fsm
;
476 /* All the info necessary to be able to extract the return
478 struct call_return_meta_info return_meta_info
;
480 /* The called function's return value. This is extracted from the
481 target before the dummy frame is popped. */
482 struct value
*return_value
;
484 /* The top level that started the infcall (and is synchronously
485 waiting for it to end). */
486 struct ui
*waiting_ui
;
489 static int call_thread_fsm_should_stop (struct thread_fsm
*self
,
490 struct thread_info
*thread
);
491 static int call_thread_fsm_should_notify_stop (struct thread_fsm
*self
);
493 /* call_thread_fsm's vtable. */
495 static struct thread_fsm_ops call_thread_fsm_ops
=
499 call_thread_fsm_should_stop
,
500 NULL
, /* return_value */
501 NULL
, /* async_reply_reason*/
502 call_thread_fsm_should_notify_stop
,
505 /* Allocate a new call_thread_fsm object. */
507 static struct call_thread_fsm
*
508 new_call_thread_fsm (struct ui
*waiting_ui
, struct interp
*cmd_interp
,
509 struct gdbarch
*gdbarch
, struct value
*function
,
510 struct type
*value_type
,
511 int struct_return_p
, CORE_ADDR struct_addr
)
513 struct call_thread_fsm
*sm
;
515 sm
= XCNEW (struct call_thread_fsm
);
516 thread_fsm_ctor (&sm
->thread_fsm
, &call_thread_fsm_ops
, cmd_interp
);
518 sm
->return_meta_info
.gdbarch
= gdbarch
;
519 sm
->return_meta_info
.function
= function
;
520 sm
->return_meta_info
.value_type
= value_type
;
521 sm
->return_meta_info
.struct_return_p
= struct_return_p
;
522 sm
->return_meta_info
.struct_addr
= struct_addr
;
524 sm
->waiting_ui
= waiting_ui
;
529 /* Implementation of should_stop method for infcalls. */
532 call_thread_fsm_should_stop (struct thread_fsm
*self
,
533 struct thread_info
*thread
)
535 struct call_thread_fsm
*f
= (struct call_thread_fsm
*) self
;
537 if (stop_stack_dummy
== STOP_STACK_DUMMY
)
540 thread_fsm_set_finished (self
);
542 /* Stash the return value before the dummy frame is popped and
543 registers are restored to what they were before the
545 f
->return_value
= get_call_return_value (&f
->return_meta_info
);
547 /* Break out of wait_sync_command_done. */
548 scoped_restore save_ui
= make_scoped_restore (¤t_ui
, f
->waiting_ui
);
549 target_terminal::ours ();
550 f
->waiting_ui
->prompt_state
= PROMPT_NEEDED
;
556 /* Implementation of should_notify_stop method for infcalls. */
559 call_thread_fsm_should_notify_stop (struct thread_fsm
*self
)
561 if (thread_fsm_finished_p (self
))
563 /* Infcall succeeded. Be silent and proceed with evaluating the
568 /* Something wrong happened. E.g., an unexpected breakpoint
569 triggered, or a signal was intercepted. Notify the stop. */
573 /* Subroutine of call_function_by_hand to simplify it.
574 Start up the inferior and wait for it to stop.
575 Return the exception if there's an error, or an exception with
576 reason >= 0 if there's no error.
578 This is done inside a TRY_CATCH so the caller needn't worry about
579 thrown errors. The caller should rethrow if there's an error. */
581 static struct gdb_exception
582 run_inferior_call (struct call_thread_fsm
*sm
,
583 struct thread_info
*call_thread
, CORE_ADDR real_pc
)
585 struct gdb_exception caught_error
= exception_none
;
586 int saved_in_infcall
= call_thread
->control
.in_infcall
;
587 ptid_t call_thread_ptid
= call_thread
->ptid
;
588 enum prompt_state saved_prompt_state
= current_ui
->prompt_state
;
589 int was_running
= call_thread
->state
== THREAD_RUNNING
;
590 int saved_ui_async
= current_ui
->async
;
592 /* Infcalls run synchronously, in the foreground. */
593 current_ui
->prompt_state
= PROMPT_BLOCKED
;
594 /* So that we don't print the prompt prematurely in
595 fetch_inferior_event. */
596 current_ui
->async
= 0;
598 delete_file_handler (current_ui
->input_fd
);
600 call_thread
->control
.in_infcall
= 1;
602 clear_proceed_status (0);
604 /* Associate the FSM with the thread after clear_proceed_status
605 (otherwise it'd clear this FSM), and before anything throws, so
606 we don't leak it (and any resources it manages). */
607 call_thread
->thread_fsm
= &sm
->thread_fsm
;
609 disable_watchpoints_before_interactive_call_start ();
611 /* We want to print return value, please... */
612 call_thread
->control
.proceed_to_finish
= 1;
616 proceed (real_pc
, GDB_SIGNAL_0
);
618 /* Inferior function calls are always synchronous, even if the
619 target supports asynchronous execution. */
620 wait_sync_command_done ();
622 CATCH (e
, RETURN_MASK_ALL
)
628 /* If GDB has the prompt blocked before, then ensure that it remains
629 so. normal_stop calls async_enable_stdin, so reset the prompt
630 state again here. In other cases, stdin will be re-enabled by
631 inferior_event_handler, when an exception is thrown. */
632 current_ui
->prompt_state
= saved_prompt_state
;
633 if (current_ui
->prompt_state
== PROMPT_BLOCKED
)
634 delete_file_handler (current_ui
->input_fd
);
636 ui_register_input_event_handler (current_ui
);
637 current_ui
->async
= saved_ui_async
;
639 /* If the infcall does NOT succeed, normal_stop will have already
640 finished the thread states. However, on success, normal_stop
641 defers here, so that we can set back the thread states to what
642 they were before the call. Note that we must also finish the
643 state of new threads that might have spawned while the call was
644 running. The main cases to handle are:
646 - "(gdb) print foo ()", or any other command that evaluates an
647 expression at the prompt. (The thread was marked stopped before.)
649 - "(gdb) break foo if return_false()" or similar cases where we
650 do an infcall while handling an event (while the thread is still
651 marked running). In this example, whether the condition
652 evaluates true and thus we'll present a user-visible stop is
653 decided elsewhere. */
655 && call_thread_ptid
== inferior_ptid
656 && stop_stack_dummy
== STOP_STACK_DUMMY
)
657 finish_thread_state (user_visible_resume_ptid (0));
659 enable_watchpoints_after_interactive_call_stop ();
661 /* Call breakpoint_auto_delete on the current contents of the bpstat
662 of inferior call thread.
663 If all error()s out of proceed ended up calling normal_stop
664 (and perhaps they should; it already does in the special case
665 of error out of resume()), then we wouldn't need this. */
666 if (caught_error
.reason
< 0)
668 if (call_thread
->state
!= THREAD_EXITED
)
669 breakpoint_auto_delete (call_thread
->control
.stop_bpstat
);
672 call_thread
->control
.in_infcall
= saved_in_infcall
;
677 /* A cleanup function that calls delete_std_terminate_breakpoint. */
679 cleanup_delete_std_terminate_breakpoint (void *ignore
)
681 delete_std_terminate_breakpoint ();
687 call_function_by_hand (struct value
*function
,
688 type
*default_return_type
,
689 int nargs
, struct value
**args
)
691 return call_function_by_hand_dummy (function
, default_return_type
,
692 nargs
, args
, NULL
, NULL
);
695 /* All this stuff with a dummy frame may seem unnecessarily complicated
696 (why not just save registers in GDB?). The purpose of pushing a dummy
697 frame which looks just like a real frame is so that if you call a
698 function and then hit a breakpoint (get a signal, etc), "backtrace"
699 will look right. Whether the backtrace needs to actually show the
700 stack at the time the inferior function was called is debatable, but
701 it certainly needs to not display garbage. So if you are contemplating
702 making dummy frames be different from normal frames, consider that. */
704 /* Perform a function call in the inferior.
705 ARGS is a vector of values of arguments (NARGS of them).
706 FUNCTION is a value, the function to be called.
707 Returns a value representing what the function returned.
708 May fail to return, if a breakpoint or signal is hit
709 during the execution of the function.
711 ARGS is modified to contain coerced values. */
714 call_function_by_hand_dummy (struct value
*function
,
715 type
*default_return_type
,
716 int nargs
, struct value
**args
,
717 dummy_frame_dtor_ftype
*dummy_dtor
,
718 void *dummy_dtor_data
)
721 struct type
*target_values_type
;
722 function_call_return_method return_method
= return_method_normal
;
723 CORE_ADDR struct_addr
= 0;
726 struct frame_id dummy_id
;
727 struct frame_info
*frame
;
728 struct gdbarch
*gdbarch
;
729 struct cleanup
*terminate_bp_cleanup
;
730 ptid_t call_thread_ptid
;
731 struct gdb_exception e
;
732 char name_buf
[RAW_FUNCTION_ADDRESS_SIZE
];
734 if (!target_has_execution
)
737 if (get_traceframe_number () >= 0)
738 error (_("May not call functions while looking at trace frames."));
740 if (execution_direction
== EXEC_REVERSE
)
741 error (_("Cannot call functions in reverse mode."));
743 /* We're going to run the target, and inspect the thread's state
744 afterwards. Hold a strong reference so that the pointer remains
745 valid even if the thread exits. */
746 thread_info_ref call_thread
747 = thread_info_ref::new_reference (inferior_thread ());
749 bool stack_temporaries
= thread_stack_temporaries_enabled_p (call_thread
.get ());
751 frame
= get_current_frame ();
752 gdbarch
= get_frame_arch (frame
);
754 if (!gdbarch_push_dummy_call_p (gdbarch
))
755 error (_("This target does not support function calls."));
757 /* A holder for the inferior status.
758 This is only needed while we're preparing the inferior function call. */
759 infcall_control_state_up
inf_status (save_infcall_control_state ());
761 /* Save the caller's registers and other state associated with the
762 inferior itself so that they can be restored once the
763 callee returns. To allow nested calls the registers are (further
764 down) pushed onto a dummy frame stack. This unique pointer
765 is released once the regcache has been pushed). */
766 infcall_suspend_state_up
caller_state (save_infcall_suspend_state ());
768 /* Ensure that the initial SP is correctly aligned. */
770 CORE_ADDR old_sp
= get_frame_sp (frame
);
772 if (gdbarch_frame_align_p (gdbarch
))
774 sp
= gdbarch_frame_align (gdbarch
, old_sp
);
775 /* NOTE: cagney/2003-08-13: Skip the "red zone". For some
776 ABIs, a function can use memory beyond the inner most stack
777 address. AMD64 called that region the "red zone". Skip at
778 least the "red zone" size before allocating any space on
780 if (gdbarch_inner_than (gdbarch
, 1, 2))
781 sp
-= gdbarch_frame_red_zone_size (gdbarch
);
783 sp
+= gdbarch_frame_red_zone_size (gdbarch
);
785 gdb_assert (sp
== gdbarch_frame_align (gdbarch
, sp
));
786 /* NOTE: cagney/2002-09-18:
788 On a RISC architecture, a void parameterless generic dummy
789 frame (i.e., no parameters, no result) typically does not
790 need to push anything the stack and hence can leave SP and
791 FP. Similarly, a frameless (possibly leaf) function does
792 not push anything on the stack and, hence, that too can
793 leave FP and SP unchanged. As a consequence, a sequence of
794 void parameterless generic dummy frame calls to frameless
795 functions will create a sequence of effectively identical
796 frames (SP, FP and TOS and PC the same). This, not
797 suprisingly, results in what appears to be a stack in an
798 infinite loop --- when GDB tries to find a generic dummy
799 frame on the internal dummy frame stack, it will always
802 To avoid this problem, the code below always grows the
803 stack. That way, two dummy frames can never be identical.
804 It does burn a few bytes of stack but that is a small price
808 if (gdbarch_inner_than (gdbarch
, 1, 2))
809 /* Stack grows down. */
810 sp
= gdbarch_frame_align (gdbarch
, old_sp
- 1);
812 /* Stack grows up. */
813 sp
= gdbarch_frame_align (gdbarch
, old_sp
+ 1);
815 /* SP may have underflown address zero here from OLD_SP. Memory access
816 functions will probably fail in such case but that is a target's
820 /* FIXME: cagney/2002-09-18: Hey, you loose!
822 Who knows how badly aligned the SP is!
824 If the generic dummy frame ends up empty (because nothing is
825 pushed) GDB won't be able to correctly perform back traces.
826 If a target is having trouble with backtraces, first thing to
827 do is add FRAME_ALIGN() to the architecture vector. If that
828 fails, try dummy_id().
830 If the ABI specifies a "Red Zone" (see the doco) the code
831 below will quietly trash it. */
834 /* Skip over the stack temporaries that might have been generated during
835 the evaluation of an expression. */
836 if (stack_temporaries
)
838 struct value
*lastval
;
840 lastval
= get_last_thread_stack_temporary (call_thread
.get ());
843 CORE_ADDR lastval_addr
= value_address (lastval
);
845 if (gdbarch_inner_than (gdbarch
, 1, 2))
847 gdb_assert (sp
>= lastval_addr
);
852 gdb_assert (sp
<= lastval_addr
);
853 sp
= lastval_addr
+ TYPE_LENGTH (value_type (lastval
));
856 if (gdbarch_frame_align_p (gdbarch
))
857 sp
= gdbarch_frame_align (gdbarch
, sp
);
864 CORE_ADDR funaddr
= find_function_addr (function
, &values_type
, &ftype
);
866 if (values_type
== NULL
)
867 values_type
= default_return_type
;
868 if (values_type
== NULL
)
870 const char *name
= get_function_name (funaddr
,
871 name_buf
, sizeof (name_buf
));
872 error (_("'%s' has unknown return type; "
873 "cast the call to its declared return type"),
877 values_type
= check_typedef (values_type
);
879 /* Are we returning a value using a structure return? */
881 if (gdbarch_return_in_first_hidden_param_p (gdbarch
, values_type
))
883 return_method
= return_method_hidden_param
;
885 /* Tell the target specific argument pushing routine not to
887 target_values_type
= builtin_type (gdbarch
)->builtin_void
;
891 if (using_struct_return (gdbarch
, function
, values_type
))
892 return_method
= return_method_struct
;
893 target_values_type
= values_type
;
896 gdb::observers::inferior_call_pre
.notify (inferior_ptid
, funaddr
);
898 /* Determine the location of the breakpoint (and possibly other
899 stuff) that the called function will return to. The SPARC, for a
900 function returning a structure or union, needs to make space for
901 not just the breakpoint but also an extra word containing the
902 size (?) of the structure being passed. */
904 switch (gdbarch_call_dummy_location (gdbarch
))
908 const gdb_byte
*bp_bytes
;
909 CORE_ADDR bp_addr_as_address
;
912 /* Be careful BP_ADDR is in inferior PC encoding while
913 BP_ADDR_AS_ADDRESS is a plain memory address. */
915 sp
= push_dummy_code (gdbarch
, sp
, funaddr
, args
, nargs
,
916 target_values_type
, &real_pc
, &bp_addr
,
917 get_current_regcache ());
919 /* Write a legitimate instruction at the point where the infcall
920 breakpoint is going to be inserted. While this instruction
921 is never going to be executed, a user investigating the
922 memory from GDB would see this instruction instead of random
923 uninitialized bytes. We chose the breakpoint instruction
924 as it may look as the most logical one to the user and also
925 valgrind 3.7.0 needs it for proper vgdb inferior calls.
927 If software breakpoints are unsupported for this target we
928 leave the user visible memory content uninitialized. */
930 bp_addr_as_address
= bp_addr
;
931 bp_bytes
= gdbarch_breakpoint_from_pc (gdbarch
, &bp_addr_as_address
,
933 if (bp_bytes
!= NULL
)
934 write_memory (bp_addr_as_address
, bp_bytes
, bp_size
);
939 CORE_ADDR dummy_addr
;
942 dummy_addr
= entry_point_address ();
944 /* A call dummy always consists of just a single breakpoint, so
945 its address is the same as the address of the dummy.
947 The actual breakpoint is inserted separatly so there is no need to
949 bp_addr
= dummy_addr
;
953 internal_error (__FILE__
, __LINE__
, _("bad switch"));
956 if (nargs
< TYPE_NFIELDS (ftype
))
957 error (_("Too few arguments in function call."));
959 for (int i
= nargs
- 1; i
>= 0; i
--)
962 struct type
*param_type
;
964 /* FIXME drow/2002-05-31: Should just always mark methods as
965 prototyped. Can we respect TYPE_VARARGS? Probably not. */
966 if (TYPE_CODE (ftype
) == TYPE_CODE_METHOD
)
968 if (TYPE_TARGET_TYPE (ftype
) == NULL
&& TYPE_NFIELDS (ftype
) == 0
969 && default_return_type
!= NULL
)
971 /* Calling a no-debug function with the return type
972 explicitly cast. Assume the function is prototyped,
973 with a prototype matching the types of the arguments.
975 float mult (float v1, float v2) { return v1 * v2; }
977 (gdb) p (float) mult (2.0f, 3.0f)
978 Is a simpler alternative to:
979 (gdb) p ((float (*) (float, float)) mult) (2.0f, 3.0f)
983 else if (i
< TYPE_NFIELDS (ftype
))
984 prototyped
= TYPE_PROTOTYPED (ftype
);
988 if (i
< TYPE_NFIELDS (ftype
))
989 param_type
= TYPE_FIELD_TYPE (ftype
, i
);
993 args
[i
] = value_arg_coerce (gdbarch
, args
[i
],
994 param_type
, prototyped
, &sp
);
996 if (param_type
!= NULL
&& language_pass_by_reference (param_type
))
997 args
[i
] = value_addr (args
[i
]);
1000 /* Reserve space for the return structure to be written on the
1001 stack, if necessary. Make certain that the value is correctly
1004 While evaluating expressions, we reserve space on the stack for
1005 return values of class type even if the language ABI and the target
1006 ABI do not require that the return value be passed as a hidden first
1007 argument. This is because we want to store the return value as an
1008 on-stack temporary while the expression is being evaluated. This
1009 enables us to have chained function calls in expressions.
1011 Keeping the return values as on-stack temporaries while the expression
1012 is being evaluated is OK because the thread is stopped until the
1013 expression is completely evaluated. */
1015 if (return_method
!= return_method_normal
1016 || (stack_temporaries
&& class_or_union_p (values_type
)))
1018 if (gdbarch_inner_than (gdbarch
, 1, 2))
1020 /* Stack grows downward. Align STRUCT_ADDR and SP after
1021 making space for the return value. */
1022 sp
-= TYPE_LENGTH (values_type
);
1023 if (gdbarch_frame_align_p (gdbarch
))
1024 sp
= gdbarch_frame_align (gdbarch
, sp
);
1029 /* Stack grows upward. Align the frame, allocate space, and
1030 then again, re-align the frame??? */
1031 if (gdbarch_frame_align_p (gdbarch
))
1032 sp
= gdbarch_frame_align (gdbarch
, sp
);
1034 sp
+= TYPE_LENGTH (values_type
);
1035 if (gdbarch_frame_align_p (gdbarch
))
1036 sp
= gdbarch_frame_align (gdbarch
, sp
);
1040 std::vector
<struct value
*> new_args
;
1041 if (return_method
== return_method_hidden_param
)
1043 /* Add the new argument to the front of the argument list. */
1045 (value_from_pointer (lookup_pointer_type (values_type
), struct_addr
));
1046 std::copy (&args
[0], &args
[nargs
], std::back_inserter (new_args
));
1047 args
= new_args
.data ();
1051 /* Create the dummy stack frame. Pass in the call dummy address as,
1052 presumably, the ABI code knows where, in the call dummy, the
1053 return address should be pointed. */
1054 sp
= gdbarch_push_dummy_call (gdbarch
, function
, get_current_regcache (),
1055 bp_addr
, nargs
, args
, sp
,
1056 (return_method
== return_method_struct
),
1059 /* Set up a frame ID for the dummy frame so we can pass it to
1060 set_momentary_breakpoint. We need to give the breakpoint a frame
1061 ID so that the breakpoint code can correctly re-identify the
1062 dummy breakpoint. */
1063 /* Sanity. The exact same SP value is returned by PUSH_DUMMY_CALL,
1064 saved as the dummy-frame TOS, and used by dummy_id to form
1065 the frame ID's stack address. */
1066 dummy_id
= frame_id_build (sp
, bp_addr
);
1068 /* Create a momentary breakpoint at the return address of the
1069 inferior. That way it breaks when it returns. */
1072 symtab_and_line sal
;
1073 sal
.pspace
= current_program_space
;
1075 sal
.section
= find_pc_overlay (sal
.pc
);
1077 /* Sanity. The exact same SP value is returned by
1078 PUSH_DUMMY_CALL, saved as the dummy-frame TOS, and used by
1079 dummy_id to form the frame ID's stack address. */
1081 = set_momentary_breakpoint (gdbarch
, sal
,
1082 dummy_id
, bp_call_dummy
).release ();
1084 /* set_momentary_breakpoint invalidates FRAME. */
1087 bpt
->disposition
= disp_del
;
1088 gdb_assert (bpt
->related_breakpoint
== bpt
);
1090 breakpoint
*longjmp_b
= set_longjmp_breakpoint_for_call_dummy ();
1093 /* Link BPT into the chain of LONGJMP_B. */
1094 bpt
->related_breakpoint
= longjmp_b
;
1095 while (longjmp_b
->related_breakpoint
!= bpt
->related_breakpoint
)
1096 longjmp_b
= longjmp_b
->related_breakpoint
;
1097 longjmp_b
->related_breakpoint
= bpt
;
1101 /* Create a breakpoint in std::terminate.
1102 If a C++ exception is raised in the dummy-frame, and the
1103 exception handler is (normally, and expected to be) out-of-frame,
1104 the default C++ handler will (wrongly) be called in an inferior
1105 function call. This is wrong, as an exception can be normally
1106 and legally handled out-of-frame. The confines of the dummy frame
1107 prevent the unwinder from finding the correct handler (or any
1108 handler, unless it is in-frame). The default handler calls
1109 std::terminate. This will kill the inferior. Assert that
1110 terminate should never be called in an inferior function
1111 call. Place a momentary breakpoint in the std::terminate function
1112 and if triggered in the call, rewind. */
1113 if (unwind_on_terminating_exception_p
)
1114 set_std_terminate_breakpoint ();
1116 /* Everything's ready, push all the info needed to restore the
1117 caller (and identify the dummy-frame) onto the dummy-frame
1119 dummy_frame_push (caller_state
.release (), &dummy_id
, call_thread
.get ());
1120 if (dummy_dtor
!= NULL
)
1121 register_dummy_frame_dtor (dummy_id
, call_thread
.get (),
1122 dummy_dtor
, dummy_dtor_data
);
1124 /* Register a clean-up for unwind_on_terminating_exception_breakpoint. */
1125 terminate_bp_cleanup
= make_cleanup (cleanup_delete_std_terminate_breakpoint
,
1128 /* - SNIP - SNIP - SNIP - SNIP - SNIP - SNIP - SNIP - SNIP - SNIP -
1129 If you're looking to implement asynchronous dummy-frames, then
1130 just below is the place to chop this function in two.. */
1133 struct thread_fsm
*saved_sm
;
1134 struct call_thread_fsm
*sm
;
1136 /* Save the current FSM. We'll override it. */
1137 saved_sm
= call_thread
->thread_fsm
;
1138 call_thread
->thread_fsm
= NULL
;
1140 /* Save this thread's ptid, we need it later but the thread
1142 call_thread_ptid
= call_thread
->ptid
;
1144 /* Run the inferior until it stops. */
1146 /* Create the FSM used to manage the infcall. It tells infrun to
1147 not report the stop to the user, and captures the return value
1148 before the dummy frame is popped. run_inferior_call registers
1149 it with the thread ASAP. */
1150 sm
= new_call_thread_fsm (current_ui
, command_interp (),
1153 return_method
!= return_method_normal
,
1156 e
= run_inferior_call (sm
, call_thread
.get (), real_pc
);
1158 gdb::observers::inferior_call_post
.notify (call_thread_ptid
, funaddr
);
1160 if (call_thread
->state
!= THREAD_EXITED
)
1162 /* The FSM should still be the same. */
1163 gdb_assert (call_thread
->thread_fsm
== &sm
->thread_fsm
);
1165 if (thread_fsm_finished_p (call_thread
->thread_fsm
))
1167 struct value
*retval
;
1169 /* The inferior call is successful. Pop the dummy frame,
1170 which runs its destructors and restores the inferior's
1171 suspend state, and restore the inferior control
1173 dummy_frame_pop (dummy_id
, call_thread
.get ());
1174 restore_infcall_control_state (inf_status
.release ());
1176 /* Get the return value. */
1177 retval
= sm
->return_value
;
1179 /* Clean up / destroy the call FSM, and restore the
1181 thread_fsm_clean_up (call_thread
->thread_fsm
, call_thread
.get ());
1182 thread_fsm_delete (call_thread
->thread_fsm
);
1183 call_thread
->thread_fsm
= saved_sm
;
1185 maybe_remove_breakpoints ();
1187 do_cleanups (terminate_bp_cleanup
);
1188 gdb_assert (retval
!= NULL
);
1192 /* Didn't complete. Restore previous state machine, and
1193 handle the error. */
1194 call_thread
->thread_fsm
= saved_sm
;
1198 /* Rethrow an error if we got one trying to run the inferior. */
1202 const char *name
= get_function_name (funaddr
,
1203 name_buf
, sizeof (name_buf
));
1205 discard_infcall_control_state (inf_status
.release ());
1207 /* We could discard the dummy frame here if the program exited,
1208 but it will get garbage collected the next time the program is
1214 throw_error (e
.error
, _("%s\n\
1215 An error occurred while in a function called from GDB.\n\
1216 Evaluation of the expression containing the function\n\
1217 (%s) will be abandoned.\n\
1218 When the function is done executing, GDB will silently stop."),
1222 throw_exception (e
);
1226 /* If the program has exited, or we stopped at a different thread,
1227 exit and inform the user. */
1229 if (! target_has_execution
)
1231 const char *name
= get_function_name (funaddr
,
1232 name_buf
, sizeof (name_buf
));
1234 /* If we try to restore the inferior status,
1235 we'll crash as the inferior is no longer running. */
1236 discard_infcall_control_state (inf_status
.release ());
1238 /* We could discard the dummy frame here given that the program exited,
1239 but it will get garbage collected the next time the program is
1242 error (_("The program being debugged exited while in a function "
1243 "called from GDB.\n"
1244 "Evaluation of the expression containing the function\n"
1245 "(%s) will be abandoned."),
1249 if (call_thread_ptid
!= inferior_ptid
)
1251 const char *name
= get_function_name (funaddr
,
1252 name_buf
, sizeof (name_buf
));
1254 /* We've switched threads. This can happen if another thread gets a
1255 signal or breakpoint while our thread was running.
1256 There's no point in restoring the inferior status,
1257 we're in a different thread. */
1258 discard_infcall_control_state (inf_status
.release ());
1259 /* Keep the dummy frame record, if the user switches back to the
1260 thread with the hand-call, we'll need it. */
1261 if (stopped_by_random_signal
)
1263 The program received a signal in another thread while\n\
1264 making a function call from GDB.\n\
1265 Evaluation of the expression containing the function\n\
1266 (%s) will be abandoned.\n\
1267 When the function is done executing, GDB will silently stop."),
1271 The program stopped in another thread while making a function call from GDB.\n\
1272 Evaluation of the expression containing the function\n\
1273 (%s) will be abandoned.\n\
1274 When the function is done executing, GDB will silently stop."),
1279 /* Make a copy as NAME may be in an objfile freed by dummy_frame_pop. */
1280 std::string name
= get_function_name (funaddr
, name_buf
,
1283 if (stopped_by_random_signal
)
1285 /* We stopped inside the FUNCTION because of a random
1286 signal. Further execution of the FUNCTION is not
1289 if (unwind_on_signal_p
)
1291 /* The user wants the context restored. */
1293 /* We must get back to the frame we were before the
1295 dummy_frame_pop (dummy_id
, call_thread
.get ());
1297 /* We also need to restore inferior status to that before the
1299 restore_infcall_control_state (inf_status
.release ());
1301 /* FIXME: Insert a bunch of wrap_here; name can be very
1302 long if it's a C++ name with arguments and stuff. */
1304 The program being debugged was signaled while in a function called from GDB.\n\
1305 GDB has restored the context to what it was before the call.\n\
1306 To change this behavior use \"set unwindonsignal off\".\n\
1307 Evaluation of the expression containing the function\n\
1308 (%s) will be abandoned."),
1313 /* The user wants to stay in the frame where we stopped
1315 Discard inferior status, we're not at the same point
1317 discard_infcall_control_state (inf_status
.release ());
1319 /* FIXME: Insert a bunch of wrap_here; name can be very
1320 long if it's a C++ name with arguments and stuff. */
1322 The program being debugged was signaled while in a function called from GDB.\n\
1323 GDB remains in the frame where the signal was received.\n\
1324 To change this behavior use \"set unwindonsignal on\".\n\
1325 Evaluation of the expression containing the function\n\
1326 (%s) will be abandoned.\n\
1327 When the function is done executing, GDB will silently stop."),
1332 if (stop_stack_dummy
== STOP_STD_TERMINATE
)
1334 /* We must get back to the frame we were before the dummy
1336 dummy_frame_pop (dummy_id
, call_thread
.get ());
1338 /* We also need to restore inferior status to that before
1340 restore_infcall_control_state (inf_status
.release ());
1343 The program being debugged entered a std::terminate call, most likely\n\
1344 caused by an unhandled C++ exception. GDB blocked this call in order\n\
1345 to prevent the program from being terminated, and has restored the\n\
1346 context to its original state before the call.\n\
1347 To change this behaviour use \"set unwind-on-terminating-exception off\".\n\
1348 Evaluation of the expression containing the function (%s)\n\
1349 will be abandoned."),
1352 else if (stop_stack_dummy
== STOP_NONE
)
1355 /* We hit a breakpoint inside the FUNCTION.
1356 Keep the dummy frame, the user may want to examine its state.
1357 Discard inferior status, we're not at the same point
1359 discard_infcall_control_state (inf_status
.release ());
1361 /* The following error message used to say "The expression
1362 which contained the function call has been discarded."
1363 It is a hard concept to explain in a few words. Ideally,
1364 GDB would be able to resume evaluation of the expression
1365 when the function finally is done executing. Perhaps
1366 someday this will be implemented (it would not be easy). */
1367 /* FIXME: Insert a bunch of wrap_here; name can be very long if it's
1368 a C++ name with arguments and stuff. */
1370 The program being debugged stopped while in a function called from GDB.\n\
1371 Evaluation of the expression containing the function\n\
1372 (%s) will be abandoned.\n\
1373 When the function is done executing, GDB will silently stop."),
1379 /* The above code errors out, so ... */
1380 gdb_assert_not_reached ("... should not be here");
1384 _initialize_infcall (void)
1386 add_setshow_boolean_cmd ("coerce-float-to-double", class_obscure
,
1387 &coerce_float_to_double_p
, _("\
1388 Set coercion of floats to doubles when calling functions."), _("\
1389 Show coercion of floats to doubles when calling functions"), _("\
1390 Variables of type float should generally be converted to doubles before\n\
1391 calling an unprototyped function, and left alone when calling a prototyped\n\
1392 function. However, some older debug info formats do not provide enough\n\
1393 information to determine that a function is prototyped. If this flag is\n\
1394 set, GDB will perform the conversion for a function it considers\n\
1396 The default is to perform the conversion.\n"),
1398 show_coerce_float_to_double_p
,
1399 &setlist
, &showlist
);
1401 add_setshow_boolean_cmd ("unwindonsignal", no_class
,
1402 &unwind_on_signal_p
, _("\
1403 Set unwinding of stack if a signal is received while in a call dummy."), _("\
1404 Show unwinding of stack if a signal is received while in a call dummy."), _("\
1405 The unwindonsignal lets the user determine what gdb should do if a signal\n\
1406 is received while in a function called from gdb (call dummy). If set, gdb\n\
1407 unwinds the stack and restore the context to what as it was before the call.\n\
1408 The default is to stop in the frame where the signal was received."),
1410 show_unwind_on_signal_p
,
1411 &setlist
, &showlist
);
1413 add_setshow_boolean_cmd ("unwind-on-terminating-exception", no_class
,
1414 &unwind_on_terminating_exception_p
, _("\
1415 Set unwinding of stack if std::terminate is called while in call dummy."), _("\
1416 Show unwinding of stack if std::terminate() is called while in a call dummy."),
1418 The unwind on terminating exception flag lets the user determine\n\
1419 what gdb should do if a std::terminate() call is made from the\n\
1420 default exception handler. If set, gdb unwinds the stack and restores\n\
1421 the context to what it was before the call. If unset, gdb allows the\n\
1422 std::terminate call to proceed.\n\
1423 The default is to unwind the frame."),
1425 show_unwind_on_terminating_exception_p
,
1426 &setlist
, &showlist
);