1 /* Perform an inferior function call, for GDB, the GNU debugger.
3 Copyright (C) 1986-2016 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"
41 #include "thread-fsm.h"
43 /* If we can't find a function's name from its address,
44 we print this instead. */
45 #define RAW_FUNCTION_ADDRESS_FORMAT "at 0x%s"
46 #define RAW_FUNCTION_ADDRESS_SIZE (sizeof (RAW_FUNCTION_ADDRESS_FORMAT) \
47 + 2 * sizeof (CORE_ADDR))
49 /* NOTE: cagney/2003-04-16: What's the future of this code?
51 GDB needs an asynchronous expression evaluator, that means an
52 asynchronous inferior function call implementation, and that in
53 turn means restructuring the code so that it is event driven. */
55 /* How you should pass arguments to a function depends on whether it
56 was defined in K&R style or prototype style. If you define a
57 function using the K&R syntax that takes a `float' argument, then
58 callers must pass that argument as a `double'. If you define the
59 function using the prototype syntax, then you must pass the
60 argument as a `float', with no promotion.
62 Unfortunately, on certain older platforms, the debug info doesn't
63 indicate reliably how each function was defined. A function type's
64 TYPE_FLAG_PROTOTYPED flag may be clear, even if the function was
65 defined in prototype style. When calling a function whose
66 TYPE_FLAG_PROTOTYPED flag is clear, GDB consults this flag to
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
))
162 struct value
*new_value
;
164 if (TYPE_CODE (arg_type
) == TYPE_CODE_REF
)
165 return value_cast_pointers (type
, arg
, 0);
167 /* Cast the value to the reference's target type, and then
168 convert it back to a reference. This will issue an error
169 if the value was not previously in memory - in some cases
170 we should clearly be allowing this, but how? */
171 new_value
= value_cast (TYPE_TARGET_TYPE (type
), arg
);
172 new_value
= value_ref (new_value
);
179 /* If we don't have a prototype, coerce to integer type if necessary. */
182 if (TYPE_LENGTH (type
) < TYPE_LENGTH (builtin
->builtin_int
))
183 type
= builtin
->builtin_int
;
185 /* Currently all target ABIs require at least the width of an integer
186 type for an argument. We may have to conditionalize the following
187 type coercion for future targets. */
188 if (TYPE_LENGTH (type
) < TYPE_LENGTH (builtin
->builtin_int
))
189 type
= builtin
->builtin_int
;
192 if (!is_prototyped
&& coerce_float_to_double_p
)
194 if (TYPE_LENGTH (type
) < TYPE_LENGTH (builtin
->builtin_double
))
195 type
= builtin
->builtin_double
;
196 else if (TYPE_LENGTH (type
) > TYPE_LENGTH (builtin
->builtin_double
))
197 type
= builtin
->builtin_long_double
;
201 type
= lookup_pointer_type (type
);
203 case TYPE_CODE_ARRAY
:
204 /* Arrays are coerced to pointers to their first element, unless
205 they are vectors, in which case we want to leave them alone,
206 because they are passed by value. */
207 if (current_language
->c_style_arrays
)
208 if (!TYPE_VECTOR (type
))
209 type
= lookup_pointer_type (TYPE_TARGET_TYPE (type
));
211 case TYPE_CODE_UNDEF
:
213 case TYPE_CODE_STRUCT
:
214 case TYPE_CODE_UNION
:
217 case TYPE_CODE_RANGE
:
218 case TYPE_CODE_STRING
:
219 case TYPE_CODE_ERROR
:
220 case TYPE_CODE_MEMBERPTR
:
221 case TYPE_CODE_METHODPTR
:
222 case TYPE_CODE_METHOD
:
223 case TYPE_CODE_COMPLEX
:
228 return value_cast (type
, arg
);
231 /* Return the return type of a function with its first instruction exactly at
232 the PC address. Return NULL otherwise. */
235 find_function_return_type (CORE_ADDR pc
)
237 struct symbol
*sym
= find_pc_function (pc
);
239 if (sym
!= NULL
&& BLOCK_START (SYMBOL_BLOCK_VALUE (sym
)) == pc
240 && SYMBOL_TYPE (sym
) != NULL
)
241 return TYPE_TARGET_TYPE (SYMBOL_TYPE (sym
));
246 /* Determine a function's address and its return type from its value.
247 Calls error() if the function is not valid for calling. */
250 find_function_addr (struct value
*function
, struct type
**retval_type
)
252 struct type
*ftype
= check_typedef (value_type (function
));
253 struct gdbarch
*gdbarch
= get_type_arch (ftype
);
254 struct type
*value_type
= NULL
;
255 /* Initialize it just to avoid a GCC false warning. */
256 CORE_ADDR funaddr
= 0;
258 /* If it's a member function, just look at the function
261 /* Determine address to call. */
262 if (TYPE_CODE (ftype
) == TYPE_CODE_FUNC
263 || TYPE_CODE (ftype
) == TYPE_CODE_METHOD
)
264 funaddr
= value_address (function
);
265 else if (TYPE_CODE (ftype
) == TYPE_CODE_PTR
)
267 funaddr
= value_as_address (function
);
268 ftype
= check_typedef (TYPE_TARGET_TYPE (ftype
));
269 if (TYPE_CODE (ftype
) == TYPE_CODE_FUNC
270 || TYPE_CODE (ftype
) == TYPE_CODE_METHOD
)
271 funaddr
= gdbarch_convert_from_func_ptr_addr (gdbarch
, funaddr
,
274 if (TYPE_CODE (ftype
) == TYPE_CODE_FUNC
275 || TYPE_CODE (ftype
) == TYPE_CODE_METHOD
)
277 value_type
= TYPE_TARGET_TYPE (ftype
);
279 if (TYPE_GNU_IFUNC (ftype
))
281 funaddr
= gnu_ifunc_resolve_addr (gdbarch
, funaddr
);
283 /* Skip querying the function symbol if no RETVAL_TYPE has been
286 value_type
= find_function_return_type (funaddr
);
289 else if (TYPE_CODE (ftype
) == TYPE_CODE_INT
)
291 /* Handle the case of functions lacking debugging info.
292 Their values are characters since their addresses are char. */
293 if (TYPE_LENGTH (ftype
) == 1)
294 funaddr
= value_as_address (value_addr (function
));
297 /* Handle function descriptors lacking debug info. */
298 int found_descriptor
= 0;
300 funaddr
= 0; /* pacify "gcc -Werror" */
301 if (VALUE_LVAL (function
) == lval_memory
)
305 funaddr
= value_as_address (value_addr (function
));
307 funaddr
= gdbarch_convert_from_func_ptr_addr (gdbarch
, funaddr
,
309 if (funaddr
!= nfunaddr
)
310 found_descriptor
= 1;
312 if (!found_descriptor
)
313 /* Handle integer used as address of a function. */
314 funaddr
= (CORE_ADDR
) value_as_long (function
);
318 error (_("Invalid data type for function to be called."));
320 if (retval_type
!= NULL
)
321 *retval_type
= value_type
;
322 return funaddr
+ gdbarch_deprecated_function_start_offset (gdbarch
);
325 /* For CALL_DUMMY_ON_STACK, push a breakpoint sequence that the called
326 function returns to. */
329 push_dummy_code (struct gdbarch
*gdbarch
,
330 CORE_ADDR sp
, CORE_ADDR funaddr
,
331 struct value
**args
, int nargs
,
332 struct type
*value_type
,
333 CORE_ADDR
*real_pc
, CORE_ADDR
*bp_addr
,
334 struct regcache
*regcache
)
336 gdb_assert (gdbarch_push_dummy_code_p (gdbarch
));
338 return gdbarch_push_dummy_code (gdbarch
, sp
, funaddr
,
339 args
, nargs
, value_type
, real_pc
, bp_addr
,
343 /* Fetch the name of the function at FUNADDR.
344 This is used in printing an error message for call_function_by_hand.
345 BUF is used to print FUNADDR in hex if the function name cannot be
346 determined. It must be large enough to hold formatted result of
347 RAW_FUNCTION_ADDRESS_FORMAT. */
350 get_function_name (CORE_ADDR funaddr
, char *buf
, int buf_size
)
353 struct symbol
*symbol
= find_pc_function (funaddr
);
356 return SYMBOL_PRINT_NAME (symbol
);
360 /* Try the minimal symbols. */
361 struct bound_minimal_symbol msymbol
= lookup_minimal_symbol_by_pc (funaddr
);
364 return MSYMBOL_PRINT_NAME (msymbol
.minsym
);
368 char *tmp
= xstrprintf (_(RAW_FUNCTION_ADDRESS_FORMAT
),
369 hex_string (funaddr
));
371 gdb_assert (strlen (tmp
) + 1 <= buf_size
);
378 /* All the meta data necessary to extract the call's return value. */
380 struct call_return_meta_info
382 /* The caller frame's architecture. */
383 struct gdbarch
*gdbarch
;
385 /* The called function. */
386 struct value
*function
;
388 /* The return value's type. */
389 struct type
*value_type
;
391 /* Are we returning a value using a structure return or a normal
395 /* If using a structure return, this is the structure's address. */
396 CORE_ADDR struct_addr
;
398 /* Whether stack temporaries are enabled. */
399 int stack_temporaries_enabled
;
402 /* Extract the called function's return value. */
404 static struct value
*
405 get_call_return_value (struct call_return_meta_info
*ri
)
407 struct value
*retval
= NULL
;
408 int stack_temporaries
= thread_stack_temporaries_enabled_p (inferior_ptid
);
410 if (TYPE_CODE (ri
->value_type
) == TYPE_CODE_VOID
)
411 retval
= allocate_value (ri
->value_type
);
412 else if (ri
->struct_return_p
)
414 if (stack_temporaries
)
416 retval
= value_from_contents_and_address (ri
->value_type
, NULL
,
418 push_thread_stack_temporary (inferior_ptid
, retval
);
422 retval
= allocate_value (ri
->value_type
);
423 read_value_memory (retval
, 0, 1, ri
->struct_addr
,
424 value_contents_raw (retval
),
425 TYPE_LENGTH (ri
->value_type
));
430 retval
= allocate_value (ri
->value_type
);
431 gdbarch_return_value (ri
->gdbarch
, ri
->function
, ri
->value_type
,
432 get_current_regcache (),
433 value_contents_raw (retval
), NULL
);
434 if (stack_temporaries
&& class_or_union_p (ri
->value_type
))
436 /* Values of class type returned in registers are copied onto
437 the stack and their lval_type set to lval_memory. This is
438 required because further evaluation of the expression
439 could potentially invoke methods on the return value
440 requiring GDB to evaluate the "this" pointer. To evaluate
441 the this pointer, GDB needs the memory address of the
443 value_force_lval (retval
, ri
->struct_addr
);
444 push_thread_stack_temporary (inferior_ptid
, retval
);
448 gdb_assert (retval
!= NULL
);
452 /* Data for the FSM that manages an infcall. It's main job is to
453 record the called function's return value. */
455 struct call_thread_fsm
457 /* The base class. */
458 struct thread_fsm thread_fsm
;
460 /* All the info necessary to be able to extract the return
462 struct call_return_meta_info return_meta_info
;
464 /* The called function's return value. This is extracted from the
465 target before the dummy frame is popped. */
466 struct value
*return_value
;
468 /* The top level that started the infcall (and is synchronously
469 waiting for it to end). */
470 struct ui
*waiting_ui
;
473 static int call_thread_fsm_should_stop (struct thread_fsm
*self
);
474 static int call_thread_fsm_should_notify_stop (struct thread_fsm
*self
);
476 /* call_thread_fsm's vtable. */
478 static struct thread_fsm_ops call_thread_fsm_ops
=
482 call_thread_fsm_should_stop
,
483 NULL
, /* return_value */
484 NULL
, /* async_reply_reason*/
485 call_thread_fsm_should_notify_stop
,
488 /* Allocate a new call_thread_fsm object. */
490 static struct call_thread_fsm
*
491 new_call_thread_fsm (struct ui
*waiting_ui
,
492 struct gdbarch
*gdbarch
, struct value
*function
,
493 struct type
*value_type
,
494 int struct_return_p
, CORE_ADDR struct_addr
)
496 struct call_thread_fsm
*sm
;
498 sm
= XCNEW (struct call_thread_fsm
);
499 thread_fsm_ctor (&sm
->thread_fsm
, &call_thread_fsm_ops
);
501 sm
->return_meta_info
.gdbarch
= gdbarch
;
502 sm
->return_meta_info
.function
= function
;
503 sm
->return_meta_info
.value_type
= value_type
;
504 sm
->return_meta_info
.struct_return_p
= struct_return_p
;
505 sm
->return_meta_info
.struct_addr
= struct_addr
;
507 sm
->waiting_ui
= waiting_ui
;
512 /* Implementation of should_stop method for infcalls. */
515 call_thread_fsm_should_stop (struct thread_fsm
*self
)
517 struct call_thread_fsm
*f
= (struct call_thread_fsm
*) self
;
519 if (stop_stack_dummy
== STOP_STACK_DUMMY
)
521 struct cleanup
*old_chain
;
524 thread_fsm_set_finished (self
);
526 /* Stash the return value before the dummy frame is popped and
527 registers are restored to what they were before the
529 f
->return_value
= get_call_return_value (&f
->return_meta_info
);
531 /* Break out of wait_sync_command_done. */
532 old_chain
= make_cleanup (restore_ui_cleanup
, current_ui
);
533 current_ui
= f
->waiting_ui
;
534 target_terminal_ours ();
535 f
->waiting_ui
->prompt_state
= PROMPT_NEEDED
;
537 /* This restores the previous UI. */
538 do_cleanups (old_chain
);
544 /* Implementation of should_notify_stop method for infcalls. */
547 call_thread_fsm_should_notify_stop (struct thread_fsm
*self
)
549 if (thread_fsm_finished_p (self
))
551 /* Infcall succeeded. Be silent and proceed with evaluating the
556 /* Something wrong happened. E.g., an unexpected breakpoint
557 triggered, or a signal was intercepted. Notify the stop. */
561 /* Subroutine of call_function_by_hand to simplify it.
562 Start up the inferior and wait for it to stop.
563 Return the exception if there's an error, or an exception with
564 reason >= 0 if there's no error.
566 This is done inside a TRY_CATCH so the caller needn't worry about
567 thrown errors. The caller should rethrow if there's an error. */
569 static struct gdb_exception
570 run_inferior_call (struct call_thread_fsm
*sm
,
571 struct thread_info
*call_thread
, CORE_ADDR real_pc
)
573 struct gdb_exception caught_error
= exception_none
;
574 int saved_in_infcall
= call_thread
->control
.in_infcall
;
575 ptid_t call_thread_ptid
= call_thread
->ptid
;
576 enum prompt_state saved_prompt_state
= current_ui
->prompt_state
;
577 int was_running
= call_thread
->state
== THREAD_RUNNING
;
578 int saved_ui_async
= current_ui
->async
;
580 /* Infcalls run synchronously, in the foreground. */
581 current_ui
->prompt_state
= PROMPT_BLOCKED
;
582 /* So that we don't print the prompt prematurely in
583 fetch_inferior_event. */
584 current_ui
->async
= 0;
586 call_thread
->control
.in_infcall
= 1;
588 clear_proceed_status (0);
590 /* Associate the FSM with the thread after clear_proceed_status
591 (otherwise it'd clear this FSM), and before anything throws, so
592 we don't leak it (and any resources it manages). */
593 call_thread
->thread_fsm
= &sm
->thread_fsm
;
595 disable_watchpoints_before_interactive_call_start ();
597 /* We want to print return value, please... */
598 call_thread
->control
.proceed_to_finish
= 1;
602 proceed (real_pc
, GDB_SIGNAL_0
);
604 /* Inferior function calls are always synchronous, even if the
605 target supports asynchronous execution. */
606 wait_sync_command_done ();
608 CATCH (e
, RETURN_MASK_ALL
)
614 /* If GDB has the prompt blocked before, then ensure that it remains
615 so. normal_stop calls async_enable_stdin, so reset the prompt
616 state again here. In other cases, stdin will be re-enabled by
617 inferior_event_handler, when an exception is thrown. */
618 current_ui
->prompt_state
= saved_prompt_state
;
619 current_ui
->async
= saved_ui_async
;
621 /* At this point the current thread may have changed. Refresh
622 CALL_THREAD as it could be invalid if its thread has exited. */
623 call_thread
= find_thread_ptid (call_thread_ptid
);
625 /* If the infcall does NOT succeed, normal_stop will have already
626 finished the thread states. However, on success, normal_stop
627 defers here, so that we can set back the thread states to what
628 they were before the call. Note that we must also finish the
629 state of new threads that might have spawned while the call was
630 running. The main cases to handle are:
632 - "(gdb) print foo ()", or any other command that evaluates an
633 expression at the prompt. (The thread was marked stopped before.)
635 - "(gdb) break foo if return_false()" or similar cases where we
636 do an infcall while handling an event (while the thread is still
637 marked running). In this example, whether the condition
638 evaluates true and thus we'll present a user-visible stop is
639 decided elsewhere. */
641 && ptid_equal (call_thread_ptid
, inferior_ptid
)
642 && stop_stack_dummy
== STOP_STACK_DUMMY
)
643 finish_thread_state (user_visible_resume_ptid (0));
645 enable_watchpoints_after_interactive_call_stop ();
647 /* Call breakpoint_auto_delete on the current contents of the bpstat
648 of inferior call thread.
649 If all error()s out of proceed ended up calling normal_stop
650 (and perhaps they should; it already does in the special case
651 of error out of resume()), then we wouldn't need this. */
652 if (caught_error
.reason
< 0)
654 if (call_thread
!= NULL
)
655 breakpoint_auto_delete (call_thread
->control
.stop_bpstat
);
658 if (call_thread
!= NULL
)
659 call_thread
->control
.in_infcall
= saved_in_infcall
;
664 /* A cleanup function that calls delete_std_terminate_breakpoint. */
666 cleanup_delete_std_terminate_breakpoint (void *ignore
)
668 delete_std_terminate_breakpoint ();
674 call_function_by_hand (struct value
*function
, int nargs
, struct value
**args
)
676 return call_function_by_hand_dummy (function
, nargs
, args
, NULL
, NULL
);
679 /* All this stuff with a dummy frame may seem unnecessarily complicated
680 (why not just save registers in GDB?). The purpose of pushing a dummy
681 frame which looks just like a real frame is so that if you call a
682 function and then hit a breakpoint (get a signal, etc), "backtrace"
683 will look right. Whether the backtrace needs to actually show the
684 stack at the time the inferior function was called is debatable, but
685 it certainly needs to not display garbage. So if you are contemplating
686 making dummy frames be different from normal frames, consider that. */
688 /* Perform a function call in the inferior.
689 ARGS is a vector of values of arguments (NARGS of them).
690 FUNCTION is a value, the function to be called.
691 Returns a value representing what the function returned.
692 May fail to return, if a breakpoint or signal is hit
693 during the execution of the function.
695 ARGS is modified to contain coerced values. */
698 call_function_by_hand_dummy (struct value
*function
,
699 int nargs
, struct value
**args
,
700 dummy_frame_dtor_ftype
*dummy_dtor
,
701 void *dummy_dtor_data
)
704 struct type
*values_type
, *target_values_type
;
705 unsigned char struct_return
= 0, hidden_first_param_p
= 0;
706 CORE_ADDR struct_addr
= 0;
707 struct infcall_control_state
*inf_status
;
708 struct cleanup
*inf_status_cleanup
;
709 struct infcall_suspend_state
*caller_state
;
712 struct type
*ftype
= check_typedef (value_type (function
));
714 struct frame_id dummy_id
;
715 struct cleanup
*args_cleanup
;
716 struct frame_info
*frame
;
717 struct gdbarch
*gdbarch
;
718 struct cleanup
*terminate_bp_cleanup
;
719 ptid_t call_thread_ptid
;
720 struct gdb_exception e
;
721 char name_buf
[RAW_FUNCTION_ADDRESS_SIZE
];
722 int stack_temporaries
= thread_stack_temporaries_enabled_p (inferior_ptid
);
724 if (TYPE_CODE (ftype
) == TYPE_CODE_PTR
)
725 ftype
= check_typedef (TYPE_TARGET_TYPE (ftype
));
727 if (!target_has_execution
)
730 if (get_traceframe_number () >= 0)
731 error (_("May not call functions while looking at trace frames."));
733 if (execution_direction
== EXEC_REVERSE
)
734 error (_("Cannot call functions in reverse mode."));
736 frame
= get_current_frame ();
737 gdbarch
= get_frame_arch (frame
);
739 if (!gdbarch_push_dummy_call_p (gdbarch
))
740 error (_("This target does not support function calls."));
742 /* A cleanup for the inferior status.
743 This is only needed while we're preparing the inferior function call. */
744 inf_status
= save_infcall_control_state ();
746 = make_cleanup_restore_infcall_control_state (inf_status
);
748 /* Save the caller's registers and other state associated with the
749 inferior itself so that they can be restored once the
750 callee returns. To allow nested calls the registers are (further
751 down) pushed onto a dummy frame stack. Include a cleanup (which
752 is tossed once the regcache has been pushed). */
753 caller_state
= save_infcall_suspend_state ();
754 make_cleanup_restore_infcall_suspend_state (caller_state
);
756 /* Ensure that the initial SP is correctly aligned. */
758 CORE_ADDR old_sp
= get_frame_sp (frame
);
760 if (gdbarch_frame_align_p (gdbarch
))
762 sp
= gdbarch_frame_align (gdbarch
, old_sp
);
763 /* NOTE: cagney/2003-08-13: Skip the "red zone". For some
764 ABIs, a function can use memory beyond the inner most stack
765 address. AMD64 called that region the "red zone". Skip at
766 least the "red zone" size before allocating any space on
768 if (gdbarch_inner_than (gdbarch
, 1, 2))
769 sp
-= gdbarch_frame_red_zone_size (gdbarch
);
771 sp
+= gdbarch_frame_red_zone_size (gdbarch
);
773 gdb_assert (sp
== gdbarch_frame_align (gdbarch
, sp
));
774 /* NOTE: cagney/2002-09-18:
776 On a RISC architecture, a void parameterless generic dummy
777 frame (i.e., no parameters, no result) typically does not
778 need to push anything the stack and hence can leave SP and
779 FP. Similarly, a frameless (possibly leaf) function does
780 not push anything on the stack and, hence, that too can
781 leave FP and SP unchanged. As a consequence, a sequence of
782 void parameterless generic dummy frame calls to frameless
783 functions will create a sequence of effectively identical
784 frames (SP, FP and TOS and PC the same). This, not
785 suprisingly, results in what appears to be a stack in an
786 infinite loop --- when GDB tries to find a generic dummy
787 frame on the internal dummy frame stack, it will always
790 To avoid this problem, the code below always grows the
791 stack. That way, two dummy frames can never be identical.
792 It does burn a few bytes of stack but that is a small price
796 if (gdbarch_inner_than (gdbarch
, 1, 2))
797 /* Stack grows down. */
798 sp
= gdbarch_frame_align (gdbarch
, old_sp
- 1);
800 /* Stack grows up. */
801 sp
= gdbarch_frame_align (gdbarch
, old_sp
+ 1);
803 /* SP may have underflown address zero here from OLD_SP. Memory access
804 functions will probably fail in such case but that is a target's
808 /* FIXME: cagney/2002-09-18: Hey, you loose!
810 Who knows how badly aligned the SP is!
812 If the generic dummy frame ends up empty (because nothing is
813 pushed) GDB won't be able to correctly perform back traces.
814 If a target is having trouble with backtraces, first thing to
815 do is add FRAME_ALIGN() to the architecture vector. If that
816 fails, try dummy_id().
818 If the ABI specifies a "Red Zone" (see the doco) the code
819 below will quietly trash it. */
822 /* Skip over the stack temporaries that might have been generated during
823 the evaluation of an expression. */
824 if (stack_temporaries
)
826 struct value
*lastval
;
828 lastval
= get_last_thread_stack_temporary (inferior_ptid
);
831 CORE_ADDR lastval_addr
= value_address (lastval
);
833 if (gdbarch_inner_than (gdbarch
, 1, 2))
835 gdb_assert (sp
>= lastval_addr
);
840 gdb_assert (sp
<= lastval_addr
);
841 sp
= lastval_addr
+ TYPE_LENGTH (value_type (lastval
));
844 if (gdbarch_frame_align_p (gdbarch
))
845 sp
= gdbarch_frame_align (gdbarch
, sp
);
850 funaddr
= find_function_addr (function
, &values_type
);
852 values_type
= builtin_type (gdbarch
)->builtin_int
;
854 values_type
= check_typedef (values_type
);
856 /* Are we returning a value using a structure return (passing a
857 hidden argument pointing to storage) or a normal value return?
858 There are two cases: language-mandated structure return and
859 target ABI structure return. The variable STRUCT_RETURN only
860 describes the latter. The language version is handled by passing
861 the return location as the first parameter to the function,
862 even preceding "this". This is different from the target
863 ABI version, which is target-specific; for instance, on ia64
864 the first argument is passed in out0 but the hidden structure
865 return pointer would normally be passed in r8. */
867 if (gdbarch_return_in_first_hidden_param_p (gdbarch
, values_type
))
869 hidden_first_param_p
= 1;
871 /* Tell the target specific argument pushing routine not to
873 target_values_type
= builtin_type (gdbarch
)->builtin_void
;
877 struct_return
= using_struct_return (gdbarch
, function
, values_type
);
878 target_values_type
= values_type
;
881 observer_notify_inferior_call_pre (inferior_ptid
, funaddr
);
883 /* Determine the location of the breakpoint (and possibly other
884 stuff) that the called function will return to. The SPARC, for a
885 function returning a structure or union, needs to make space for
886 not just the breakpoint but also an extra word containing the
887 size (?) of the structure being passed. */
889 switch (gdbarch_call_dummy_location (gdbarch
))
893 const gdb_byte
*bp_bytes
;
894 CORE_ADDR bp_addr_as_address
;
897 /* Be careful BP_ADDR is in inferior PC encoding while
898 BP_ADDR_AS_ADDRESS is a plain memory address. */
900 sp
= push_dummy_code (gdbarch
, sp
, funaddr
, args
, nargs
,
901 target_values_type
, &real_pc
, &bp_addr
,
902 get_current_regcache ());
904 /* Write a legitimate instruction at the point where the infcall
905 breakpoint is going to be inserted. While this instruction
906 is never going to be executed, a user investigating the
907 memory from GDB would see this instruction instead of random
908 uninitialized bytes. We chose the breakpoint instruction
909 as it may look as the most logical one to the user and also
910 valgrind 3.7.0 needs it for proper vgdb inferior calls.
912 If software breakpoints are unsupported for this target we
913 leave the user visible memory content uninitialized. */
915 bp_addr_as_address
= bp_addr
;
916 bp_bytes
= gdbarch_breakpoint_from_pc (gdbarch
, &bp_addr_as_address
,
918 if (bp_bytes
!= NULL
)
919 write_memory (bp_addr_as_address
, bp_bytes
, bp_size
);
924 CORE_ADDR dummy_addr
;
927 dummy_addr
= entry_point_address ();
929 /* A call dummy always consists of just a single breakpoint, so
930 its address is the same as the address of the dummy.
932 The actual breakpoint is inserted separatly so there is no need to
934 bp_addr
= dummy_addr
;
938 internal_error (__FILE__
, __LINE__
, _("bad switch"));
941 if (nargs
< TYPE_NFIELDS (ftype
))
942 error (_("Too few arguments in function call."));
947 for (i
= nargs
- 1; i
>= 0; i
--)
950 struct type
*param_type
;
952 /* FIXME drow/2002-05-31: Should just always mark methods as
953 prototyped. Can we respect TYPE_VARARGS? Probably not. */
954 if (TYPE_CODE (ftype
) == TYPE_CODE_METHOD
)
956 else if (i
< TYPE_NFIELDS (ftype
))
957 prototyped
= TYPE_PROTOTYPED (ftype
);
961 if (i
< TYPE_NFIELDS (ftype
))
962 param_type
= TYPE_FIELD_TYPE (ftype
, i
);
966 args
[i
] = value_arg_coerce (gdbarch
, args
[i
],
967 param_type
, prototyped
, &sp
);
969 if (param_type
!= NULL
&& language_pass_by_reference (param_type
))
970 args
[i
] = value_addr (args
[i
]);
974 /* Reserve space for the return structure to be written on the
975 stack, if necessary. Make certain that the value is correctly
978 While evaluating expressions, we reserve space on the stack for
979 return values of class type even if the language ABI and the target
980 ABI do not require that the return value be passed as a hidden first
981 argument. This is because we want to store the return value as an
982 on-stack temporary while the expression is being evaluated. This
983 enables us to have chained function calls in expressions.
985 Keeping the return values as on-stack temporaries while the expression
986 is being evaluated is OK because the thread is stopped until the
987 expression is completely evaluated. */
989 if (struct_return
|| hidden_first_param_p
990 || (stack_temporaries
&& class_or_union_p (values_type
)))
992 if (gdbarch_inner_than (gdbarch
, 1, 2))
994 /* Stack grows downward. Align STRUCT_ADDR and SP after
995 making space for the return value. */
996 sp
-= TYPE_LENGTH (values_type
);
997 if (gdbarch_frame_align_p (gdbarch
))
998 sp
= gdbarch_frame_align (gdbarch
, sp
);
1003 /* Stack grows upward. Align the frame, allocate space, and
1004 then again, re-align the frame??? */
1005 if (gdbarch_frame_align_p (gdbarch
))
1006 sp
= gdbarch_frame_align (gdbarch
, sp
);
1008 sp
+= TYPE_LENGTH (values_type
);
1009 if (gdbarch_frame_align_p (gdbarch
))
1010 sp
= gdbarch_frame_align (gdbarch
, sp
);
1014 if (hidden_first_param_p
)
1016 struct value
**new_args
;
1018 /* Add the new argument to the front of the argument list. */
1019 new_args
= XNEWVEC (struct value
*, nargs
+ 1);
1020 new_args
[0] = value_from_pointer (lookup_pointer_type (values_type
),
1022 memcpy (&new_args
[1], &args
[0], sizeof (struct value
*) * nargs
);
1025 args_cleanup
= make_cleanup (xfree
, args
);
1028 args_cleanup
= make_cleanup (null_cleanup
, NULL
);
1030 /* Create the dummy stack frame. Pass in the call dummy address as,
1031 presumably, the ABI code knows where, in the call dummy, the
1032 return address should be pointed. */
1033 sp
= gdbarch_push_dummy_call (gdbarch
, function
, get_current_regcache (),
1034 bp_addr
, nargs
, args
,
1035 sp
, struct_return
, struct_addr
);
1037 do_cleanups (args_cleanup
);
1039 /* Set up a frame ID for the dummy frame so we can pass it to
1040 set_momentary_breakpoint. We need to give the breakpoint a frame
1041 ID so that the breakpoint code can correctly re-identify the
1042 dummy breakpoint. */
1043 /* Sanity. The exact same SP value is returned by PUSH_DUMMY_CALL,
1044 saved as the dummy-frame TOS, and used by dummy_id to form
1045 the frame ID's stack address. */
1046 dummy_id
= frame_id_build (sp
, bp_addr
);
1048 /* Create a momentary breakpoint at the return address of the
1049 inferior. That way it breaks when it returns. */
1052 struct breakpoint
*bpt
, *longjmp_b
;
1053 struct symtab_and_line sal
;
1055 init_sal (&sal
); /* initialize to zeroes */
1056 sal
.pspace
= current_program_space
;
1058 sal
.section
= find_pc_overlay (sal
.pc
);
1059 /* Sanity. The exact same SP value is returned by
1060 PUSH_DUMMY_CALL, saved as the dummy-frame TOS, and used by
1061 dummy_id to form the frame ID's stack address. */
1062 bpt
= set_momentary_breakpoint (gdbarch
, sal
, dummy_id
, bp_call_dummy
);
1064 /* set_momentary_breakpoint invalidates FRAME. */
1067 bpt
->disposition
= disp_del
;
1068 gdb_assert (bpt
->related_breakpoint
== bpt
);
1070 longjmp_b
= set_longjmp_breakpoint_for_call_dummy ();
1073 /* Link BPT into the chain of LONGJMP_B. */
1074 bpt
->related_breakpoint
= longjmp_b
;
1075 while (longjmp_b
->related_breakpoint
!= bpt
->related_breakpoint
)
1076 longjmp_b
= longjmp_b
->related_breakpoint
;
1077 longjmp_b
->related_breakpoint
= bpt
;
1081 /* Create a breakpoint in std::terminate.
1082 If a C++ exception is raised in the dummy-frame, and the
1083 exception handler is (normally, and expected to be) out-of-frame,
1084 the default C++ handler will (wrongly) be called in an inferior
1085 function call. This is wrong, as an exception can be normally
1086 and legally handled out-of-frame. The confines of the dummy frame
1087 prevent the unwinder from finding the correct handler (or any
1088 handler, unless it is in-frame). The default handler calls
1089 std::terminate. This will kill the inferior. Assert that
1090 terminate should never be called in an inferior function
1091 call. Place a momentary breakpoint in the std::terminate function
1092 and if triggered in the call, rewind. */
1093 if (unwind_on_terminating_exception_p
)
1094 set_std_terminate_breakpoint ();
1096 /* Discard both inf_status and caller_state cleanups.
1097 From this point on we explicitly restore the associated state
1099 discard_cleanups (inf_status_cleanup
);
1101 /* Everything's ready, push all the info needed to restore the
1102 caller (and identify the dummy-frame) onto the dummy-frame
1104 dummy_frame_push (caller_state
, &dummy_id
, inferior_ptid
);
1105 if (dummy_dtor
!= NULL
)
1106 register_dummy_frame_dtor (dummy_id
, inferior_ptid
,
1107 dummy_dtor
, dummy_dtor_data
);
1109 /* Register a clean-up for unwind_on_terminating_exception_breakpoint. */
1110 terminate_bp_cleanup
= make_cleanup (cleanup_delete_std_terminate_breakpoint
,
1113 /* - SNIP - SNIP - SNIP - SNIP - SNIP - SNIP - SNIP - SNIP - SNIP -
1114 If you're looking to implement asynchronous dummy-frames, then
1115 just below is the place to chop this function in two.. */
1117 /* TP is invalid after run_inferior_call returns, so enclose this
1118 in a block so that it's only in scope during the time it's valid. */
1120 struct thread_info
*tp
= inferior_thread ();
1121 struct thread_fsm
*saved_sm
;
1122 struct call_thread_fsm
*sm
;
1124 /* Save the current FSM. We'll override it. */
1125 saved_sm
= tp
->thread_fsm
;
1126 tp
->thread_fsm
= NULL
;
1128 /* Save this thread's ptid, we need it later but the thread
1130 call_thread_ptid
= tp
->ptid
;
1132 /* Run the inferior until it stops. */
1134 /* Create the FSM used to manage the infcall. It tells infrun to
1135 not report the stop to the user, and captures the return value
1136 before the dummy frame is popped. run_inferior_call registers
1137 it with the thread ASAP. */
1138 sm
= new_call_thread_fsm (current_ui
,
1141 struct_return
|| hidden_first_param_p
,
1144 e
= run_inferior_call (sm
, tp
, real_pc
);
1146 observer_notify_inferior_call_post (call_thread_ptid
, funaddr
);
1148 tp
= find_thread_ptid (call_thread_ptid
);
1151 /* The FSM should still be the same. */
1152 gdb_assert (tp
->thread_fsm
== &sm
->thread_fsm
);
1154 if (thread_fsm_finished_p (tp
->thread_fsm
))
1156 struct value
*retval
;
1158 /* The inferior call is successful. Pop the dummy frame,
1159 which runs its destructors and restores the inferior's
1160 suspend state, and restore the inferior control
1162 dummy_frame_pop (dummy_id
, call_thread_ptid
);
1163 restore_infcall_control_state (inf_status
);
1165 /* Get the return value. */
1166 retval
= sm
->return_value
;
1168 /* Clean up / destroy the call FSM, and restore the
1170 thread_fsm_clean_up (tp
->thread_fsm
);
1171 thread_fsm_delete (tp
->thread_fsm
);
1172 tp
->thread_fsm
= saved_sm
;
1174 maybe_remove_breakpoints ();
1176 do_cleanups (terminate_bp_cleanup
);
1177 gdb_assert (retval
!= NULL
);
1181 /* Didn't complete. Restore previous state machine, and
1182 handle the error. */
1183 tp
->thread_fsm
= saved_sm
;
1187 /* Rethrow an error if we got one trying to run the inferior. */
1191 const char *name
= get_function_name (funaddr
,
1192 name_buf
, sizeof (name_buf
));
1194 discard_infcall_control_state (inf_status
);
1196 /* We could discard the dummy frame here if the program exited,
1197 but it will get garbage collected the next time the program is
1203 throw_error (e
.error
, _("%s\n\
1204 An error occurred while in a function called from GDB.\n\
1205 Evaluation of the expression containing the function\n\
1206 (%s) will be abandoned.\n\
1207 When the function is done executing, GDB will silently stop."),
1211 throw_exception (e
);
1215 /* If the program has exited, or we stopped at a different thread,
1216 exit and inform the user. */
1218 if (! target_has_execution
)
1220 const char *name
= get_function_name (funaddr
,
1221 name_buf
, sizeof (name_buf
));
1223 /* If we try to restore the inferior status,
1224 we'll crash as the inferior is no longer running. */
1225 discard_infcall_control_state (inf_status
);
1227 /* We could discard the dummy frame here given that the program exited,
1228 but it will get garbage collected the next time the program is
1231 error (_("The program being debugged exited while in a function "
1232 "called from GDB.\n"
1233 "Evaluation of the expression containing the function\n"
1234 "(%s) will be abandoned."),
1238 if (! ptid_equal (call_thread_ptid
, inferior_ptid
))
1240 const char *name
= get_function_name (funaddr
,
1241 name_buf
, sizeof (name_buf
));
1243 /* We've switched threads. This can happen if another thread gets a
1244 signal or breakpoint while our thread was running.
1245 There's no point in restoring the inferior status,
1246 we're in a different thread. */
1247 discard_infcall_control_state (inf_status
);
1248 /* Keep the dummy frame record, if the user switches back to the
1249 thread with the hand-call, we'll need it. */
1250 if (stopped_by_random_signal
)
1252 The program received a signal in another thread while\n\
1253 making a function call from GDB.\n\
1254 Evaluation of the expression containing the function\n\
1255 (%s) will be abandoned.\n\
1256 When the function is done executing, GDB will silently stop."),
1260 The program stopped in another thread while making a function call from GDB.\n\
1261 Evaluation of the expression containing the function\n\
1262 (%s) will be abandoned.\n\
1263 When the function is done executing, GDB will silently stop."),
1268 /* Make a copy as NAME may be in an objfile freed by dummy_frame_pop. */
1269 char *name
= xstrdup (get_function_name (funaddr
,
1270 name_buf
, sizeof (name_buf
)));
1271 make_cleanup (xfree
, name
);
1274 if (stopped_by_random_signal
)
1276 /* We stopped inside the FUNCTION because of a random
1277 signal. Further execution of the FUNCTION is not
1280 if (unwind_on_signal_p
)
1282 /* The user wants the context restored. */
1284 /* We must get back to the frame we were before the
1286 dummy_frame_pop (dummy_id
, call_thread_ptid
);
1288 /* We also need to restore inferior status to that before the
1290 restore_infcall_control_state (inf_status
);
1292 /* FIXME: Insert a bunch of wrap_here; name can be very
1293 long if it's a C++ name with arguments and stuff. */
1295 The program being debugged was signaled while in a function called from GDB.\n\
1296 GDB has restored the context to what it was before the call.\n\
1297 To change this behavior use \"set unwindonsignal off\".\n\
1298 Evaluation of the expression containing the function\n\
1299 (%s) will be abandoned."),
1304 /* The user wants to stay in the frame where we stopped
1306 Discard inferior status, we're not at the same point
1308 discard_infcall_control_state (inf_status
);
1310 /* FIXME: Insert a bunch of wrap_here; name can be very
1311 long if it's a C++ name with arguments and stuff. */
1313 The program being debugged was signaled while in a function called from GDB.\n\
1314 GDB remains in the frame where the signal was received.\n\
1315 To change this behavior use \"set unwindonsignal on\".\n\
1316 Evaluation of the expression containing the function\n\
1317 (%s) will be abandoned.\n\
1318 When the function is done executing, GDB will silently stop."),
1323 if (stop_stack_dummy
== STOP_STD_TERMINATE
)
1325 /* We must get back to the frame we were before the dummy
1327 dummy_frame_pop (dummy_id
, call_thread_ptid
);
1329 /* We also need to restore inferior status to that before
1331 restore_infcall_control_state (inf_status
);
1334 The program being debugged entered a std::terminate call, most likely\n\
1335 caused by an unhandled C++ exception. GDB blocked this call in order\n\
1336 to prevent the program from being terminated, and has restored the\n\
1337 context to its original state before the call.\n\
1338 To change this behaviour use \"set unwind-on-terminating-exception off\".\n\
1339 Evaluation of the expression containing the function (%s)\n\
1340 will be abandoned."),
1343 else if (stop_stack_dummy
== STOP_NONE
)
1346 /* We hit a breakpoint inside the FUNCTION.
1347 Keep the dummy frame, the user may want to examine its state.
1348 Discard inferior status, we're not at the same point
1350 discard_infcall_control_state (inf_status
);
1352 /* The following error message used to say "The expression
1353 which contained the function call has been discarded."
1354 It is a hard concept to explain in a few words. Ideally,
1355 GDB would be able to resume evaluation of the expression
1356 when the function finally is done executing. Perhaps
1357 someday this will be implemented (it would not be easy). */
1358 /* FIXME: Insert a bunch of wrap_here; name can be very long if it's
1359 a C++ name with arguments and stuff. */
1361 The program being debugged stopped while in a function called from GDB.\n\
1362 Evaluation of the expression containing the function\n\
1363 (%s) will be abandoned.\n\
1364 When the function is done executing, GDB will silently stop."),
1370 /* The above code errors out, so ... */
1371 gdb_assert_not_reached ("... should not be here");
1375 /* Provide a prototype to silence -Wmissing-prototypes. */
1376 void _initialize_infcall (void);
1379 _initialize_infcall (void)
1381 add_setshow_boolean_cmd ("coerce-float-to-double", class_obscure
,
1382 &coerce_float_to_double_p
, _("\
1383 Set coercion of floats to doubles when calling functions."), _("\
1384 Show coercion of floats to doubles when calling functions"), _("\
1385 Variables of type float should generally be converted to doubles before\n\
1386 calling an unprototyped function, and left alone when calling a prototyped\n\
1387 function. However, some older debug info formats do not provide enough\n\
1388 information to determine that a function is prototyped. If this flag is\n\
1389 set, GDB will perform the conversion for a function it considers\n\
1391 The default is to perform the conversion.\n"),
1393 show_coerce_float_to_double_p
,
1394 &setlist
, &showlist
);
1396 add_setshow_boolean_cmd ("unwindonsignal", no_class
,
1397 &unwind_on_signal_p
, _("\
1398 Set unwinding of stack if a signal is received while in a call dummy."), _("\
1399 Show unwinding of stack if a signal is received while in a call dummy."), _("\
1400 The unwindonsignal lets the user determine what gdb should do if a signal\n\
1401 is received while in a function called from gdb (call dummy). If set, gdb\n\
1402 unwinds the stack and restore the context to what as it was before the call.\n\
1403 The default is to stop in the frame where the signal was received."),
1405 show_unwind_on_signal_p
,
1406 &setlist
, &showlist
);
1408 add_setshow_boolean_cmd ("unwind-on-terminating-exception", no_class
,
1409 &unwind_on_terminating_exception_p
, _("\
1410 Set unwinding of stack if std::terminate is called while in call dummy."), _("\
1411 Show unwinding of stack if std::terminate() is called while in a call dummy."),
1413 The unwind on terminating exception flag lets the user determine\n\
1414 what gdb should do if a std::terminate() call is made from the\n\
1415 default exception handler. If set, gdb unwinds the stack and restores\n\
1416 the context to what it was before the call. If unset, gdb allows the\n\
1417 std::terminate call to proceed.\n\
1418 The default is to unwind the frame."),
1420 show_unwind_on_terminating_exception_p
,
1421 &setlist
, &showlist
);