1 /* Perform an inferior function call, for GDB, the GNU debugger.
3 Copyright (C) 1986-2012 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"
26 #include "gdb_assert.h"
33 #include "gdb_string.h"
35 #include "dummy-frame.h"
37 #include "gdbthread.h"
38 #include "exceptions.h"
40 /* If we can't find a function's name from its address,
41 we print this instead. */
42 #define RAW_FUNCTION_ADDRESS_FORMAT "at 0x%s"
43 #define RAW_FUNCTION_ADDRESS_SIZE (sizeof (RAW_FUNCTION_ADDRESS_FORMAT) \
44 + 2 * sizeof (CORE_ADDR))
46 /* NOTE: cagney/2003-04-16: What's the future of this code?
48 GDB needs an asynchronous expression evaluator, that means an
49 asynchronous inferior function call implementation, and that in
50 turn means restructuring the code so that it is event driven. */
52 /* How you should pass arguments to a function depends on whether it
53 was defined in K&R style or prototype style. If you define a
54 function using the K&R syntax that takes a `float' argument, then
55 callers must pass that argument as a `double'. If you define the
56 function using the prototype syntax, then you must pass the
57 argument as a `float', with no promotion.
59 Unfortunately, on certain older platforms, the debug info doesn't
60 indicate reliably how each function was defined. A function type's
61 TYPE_FLAG_PROTOTYPED flag may be clear, even if the function was
62 defined in prototype style. When calling a function whose
63 TYPE_FLAG_PROTOTYPED flag is clear, GDB consults this flag to
66 For modern targets, it is proper to assume that, if the prototype
67 flag is clear, that can be trusted: `float' arguments should be
68 promoted to `double'. For some older targets, if the prototype
69 flag is clear, that doesn't tell us anything. The default is to
70 trust the debug information; the user can override this behavior
71 with "set coerce-float-to-double 0". */
73 static int coerce_float_to_double_p
= 1;
75 show_coerce_float_to_double_p (struct ui_file
*file
, int from_tty
,
76 struct cmd_list_element
*c
, const char *value
)
78 fprintf_filtered (file
,
79 _("Coercion of floats to doubles "
80 "when calling functions is %s.\n"),
84 /* This boolean tells what gdb should do if a signal is received while
85 in a function called from gdb (call dummy). If set, gdb unwinds
86 the stack and restore the context to what as it was before the
89 The default is to stop in the frame where the signal was received. */
91 static int unwind_on_signal_p
= 0;
93 show_unwind_on_signal_p (struct ui_file
*file
, int from_tty
,
94 struct cmd_list_element
*c
, const char *value
)
96 fprintf_filtered (file
,
97 _("Unwinding of stack if a signal is "
98 "received while in a call dummy is %s.\n"),
102 /* This boolean tells what gdb should do if a std::terminate call is
103 made while in a function called from gdb (call dummy).
104 As the confines of a single dummy stack prohibit out-of-frame
105 handlers from handling a raised exception, and as out-of-frame
106 handlers are common in C++, this can lead to no handler being found
107 by the unwinder, and a std::terminate call. This is a false positive.
108 If set, gdb unwinds the stack and restores the context to what it
111 The default is to unwind the frame if a std::terminate call is
114 static int unwind_on_terminating_exception_p
= 1;
117 show_unwind_on_terminating_exception_p (struct ui_file
*file
, int from_tty
,
118 struct cmd_list_element
*c
,
122 fprintf_filtered (file
,
123 _("Unwind stack if a C++ exception is "
124 "unhandled while in a call dummy is %s.\n"),
128 /* Perform the standard coercions that are specified
129 for arguments to be passed to C or Ada functions.
131 If PARAM_TYPE is non-NULL, it is the expected parameter type.
132 IS_PROTOTYPED is non-zero if the function declaration is prototyped.
133 SP is the stack pointer were additional data can be pushed (updating
134 its value as needed). */
136 static struct value
*
137 value_arg_coerce (struct gdbarch
*gdbarch
, struct value
*arg
,
138 struct type
*param_type
, int is_prototyped
, CORE_ADDR
*sp
)
140 const struct builtin_type
*builtin
= builtin_type (gdbarch
);
141 struct type
*arg_type
= check_typedef (value_type (arg
));
143 = param_type
? check_typedef (param_type
) : arg_type
;
145 /* Perform any Ada-specific coercion first. */
146 if (current_language
->la_language
== language_ada
)
147 arg
= ada_convert_actual (arg
, type
);
149 /* Force the value to the target if we will need its address. At
150 this point, we could allocate arguments on the stack instead of
151 calling malloc if we knew that their addresses would not be
152 saved by the called function. */
153 arg
= value_coerce_to_target (arg
);
155 switch (TYPE_CODE (type
))
159 struct value
*new_value
;
161 if (TYPE_CODE (arg_type
) == TYPE_CODE_REF
)
162 return value_cast_pointers (type
, arg
, 0);
164 /* Cast the value to the reference's target type, and then
165 convert it back to a reference. This will issue an error
166 if the value was not previously in memory - in some cases
167 we should clearly be allowing this, but how? */
168 new_value
= value_cast (TYPE_TARGET_TYPE (type
), arg
);
169 new_value
= value_ref (new_value
);
176 /* If we don't have a prototype, coerce to integer type if necessary. */
179 if (TYPE_LENGTH (type
) < TYPE_LENGTH (builtin
->builtin_int
))
180 type
= builtin
->builtin_int
;
182 /* Currently all target ABIs require at least the width of an integer
183 type for an argument. We may have to conditionalize the following
184 type coercion for future targets. */
185 if (TYPE_LENGTH (type
) < TYPE_LENGTH (builtin
->builtin_int
))
186 type
= builtin
->builtin_int
;
189 if (!is_prototyped
&& coerce_float_to_double_p
)
191 if (TYPE_LENGTH (type
) < TYPE_LENGTH (builtin
->builtin_double
))
192 type
= builtin
->builtin_double
;
193 else if (TYPE_LENGTH (type
) > TYPE_LENGTH (builtin
->builtin_double
))
194 type
= builtin
->builtin_long_double
;
198 type
= lookup_pointer_type (type
);
200 case TYPE_CODE_ARRAY
:
201 /* Arrays are coerced to pointers to their first element, unless
202 they are vectors, in which case we want to leave them alone,
203 because they are passed by value. */
204 if (current_language
->c_style_arrays
)
205 if (!TYPE_VECTOR (type
))
206 type
= lookup_pointer_type (TYPE_TARGET_TYPE (type
));
208 case TYPE_CODE_UNDEF
:
210 case TYPE_CODE_STRUCT
:
211 case TYPE_CODE_UNION
:
214 case TYPE_CODE_RANGE
:
215 case TYPE_CODE_STRING
:
216 case TYPE_CODE_BITSTRING
:
217 case TYPE_CODE_ERROR
:
218 case TYPE_CODE_MEMBERPTR
:
219 case TYPE_CODE_METHODPTR
:
220 case TYPE_CODE_METHOD
:
221 case TYPE_CODE_COMPLEX
:
226 return value_cast (type
, arg
);
229 /* Return the return type of a function with its first instruction exactly at
230 the PC address. Return NULL otherwise. */
233 find_function_return_type (CORE_ADDR pc
)
235 struct symbol
*sym
= find_pc_function (pc
);
237 if (sym
!= NULL
&& BLOCK_START (SYMBOL_BLOCK_VALUE (sym
)) == pc
238 && SYMBOL_TYPE (sym
) != NULL
)
239 return TYPE_TARGET_TYPE (SYMBOL_TYPE (sym
));
244 /* Determine a function's address and its return type from its value.
245 Calls error() if the function is not valid for calling. */
248 find_function_addr (struct value
*function
, struct type
**retval_type
)
250 struct type
*ftype
= check_typedef (value_type (function
));
251 struct gdbarch
*gdbarch
= get_type_arch (ftype
);
252 struct type
*value_type
= NULL
;
253 /* Initialize it just to avoid a GCC false warning. */
254 CORE_ADDR funaddr
= 0;
256 /* If it's a member function, just look at the function
259 /* Determine address to call. */
260 if (TYPE_CODE (ftype
) == TYPE_CODE_FUNC
261 || TYPE_CODE (ftype
) == TYPE_CODE_METHOD
)
262 funaddr
= value_address (function
);
263 else if (TYPE_CODE (ftype
) == TYPE_CODE_PTR
)
265 funaddr
= value_as_address (function
);
266 ftype
= check_typedef (TYPE_TARGET_TYPE (ftype
));
267 if (TYPE_CODE (ftype
) == TYPE_CODE_FUNC
268 || TYPE_CODE (ftype
) == TYPE_CODE_METHOD
)
269 funaddr
= gdbarch_convert_from_func_ptr_addr (gdbarch
, funaddr
,
272 if (TYPE_CODE (ftype
) == TYPE_CODE_FUNC
273 || TYPE_CODE (ftype
) == TYPE_CODE_METHOD
)
275 value_type
= TYPE_TARGET_TYPE (ftype
);
277 if (TYPE_GNU_IFUNC (ftype
))
279 funaddr
= gnu_ifunc_resolve_addr (gdbarch
, funaddr
);
281 /* Skip querying the function symbol if no RETVAL_TYPE has been
284 value_type
= find_function_return_type (funaddr
);
287 else if (TYPE_CODE (ftype
) == TYPE_CODE_INT
)
289 /* Handle the case of functions lacking debugging info.
290 Their values are characters since their addresses are char. */
291 if (TYPE_LENGTH (ftype
) == 1)
292 funaddr
= value_as_address (value_addr (function
));
295 /* Handle function descriptors lacking debug info. */
296 int found_descriptor
= 0;
298 funaddr
= 0; /* pacify "gcc -Werror" */
299 if (VALUE_LVAL (function
) == lval_memory
)
303 funaddr
= value_as_address (value_addr (function
));
305 funaddr
= gdbarch_convert_from_func_ptr_addr (gdbarch
, funaddr
,
307 if (funaddr
!= nfunaddr
)
308 found_descriptor
= 1;
310 if (!found_descriptor
)
311 /* Handle integer used as address of a function. */
312 funaddr
= (CORE_ADDR
) value_as_long (function
);
316 error (_("Invalid data type for function to be called."));
318 if (retval_type
!= NULL
)
319 *retval_type
= value_type
;
320 return funaddr
+ gdbarch_deprecated_function_start_offset (gdbarch
);
323 /* For CALL_DUMMY_ON_STACK, push a breakpoint sequence that the called
324 function returns to. */
327 push_dummy_code (struct gdbarch
*gdbarch
,
328 CORE_ADDR sp
, CORE_ADDR funaddr
,
329 struct value
**args
, int nargs
,
330 struct type
*value_type
,
331 CORE_ADDR
*real_pc
, CORE_ADDR
*bp_addr
,
332 struct regcache
*regcache
)
334 gdb_assert (gdbarch_push_dummy_code_p (gdbarch
));
336 return gdbarch_push_dummy_code (gdbarch
, sp
, funaddr
,
337 args
, nargs
, value_type
, real_pc
, bp_addr
,
341 /* Fetch the name of the function at FUNADDR.
342 This is used in printing an error message for call_function_by_hand.
343 BUF is used to print FUNADDR in hex if the function name cannot be
344 determined. It must be large enough to hold formatted result of
345 RAW_FUNCTION_ADDRESS_FORMAT. */
348 get_function_name (CORE_ADDR funaddr
, char *buf
, int buf_size
)
351 struct symbol
*symbol
= find_pc_function (funaddr
);
354 return SYMBOL_PRINT_NAME (symbol
);
358 /* Try the minimal symbols. */
359 struct minimal_symbol
*msymbol
= lookup_minimal_symbol_by_pc (funaddr
);
362 return SYMBOL_PRINT_NAME (msymbol
);
366 char *tmp
= xstrprintf (_(RAW_FUNCTION_ADDRESS_FORMAT
),
367 hex_string (funaddr
));
369 gdb_assert (strlen (tmp
) + 1 <= buf_size
);
376 /* Subroutine of call_function_by_hand to simplify it.
377 Start up the inferior and wait for it to stop.
378 Return the exception if there's an error, or an exception with
379 reason >= 0 if there's no error.
381 This is done inside a TRY_CATCH so the caller needn't worry about
382 thrown errors. The caller should rethrow if there's an error. */
384 static struct gdb_exception
385 run_inferior_call (struct thread_info
*call_thread
, CORE_ADDR real_pc
)
387 volatile struct gdb_exception e
;
388 int saved_in_infcall
= call_thread
->control
.in_infcall
;
389 ptid_t call_thread_ptid
= call_thread
->ptid
;
391 call_thread
->control
.in_infcall
= 1;
393 clear_proceed_status ();
395 disable_watchpoints_before_interactive_call_start ();
397 /* We want stop_registers, please... */
398 call_thread
->control
.proceed_to_finish
= 1;
400 TRY_CATCH (e
, RETURN_MASK_ALL
)
402 proceed (real_pc
, GDB_SIGNAL_0
, 0);
404 /* Inferior function calls are always synchronous, even if the
405 target supports asynchronous execution. Do here what
406 `proceed' itself does in sync mode. */
407 if (target_can_async_p () && is_running (inferior_ptid
))
409 wait_for_inferior ();
414 /* At this point the current thread may have changed. Refresh
415 CALL_THREAD as it could be invalid if its thread has exited. */
416 call_thread
= find_thread_ptid (call_thread_ptid
);
418 enable_watchpoints_after_interactive_call_stop ();
420 /* Call breakpoint_auto_delete on the current contents of the bpstat
421 of inferior call thread.
422 If all error()s out of proceed ended up calling normal_stop
423 (and perhaps they should; it already does in the special case
424 of error out of resume()), then we wouldn't need this. */
427 if (call_thread
!= NULL
)
428 breakpoint_auto_delete (call_thread
->control
.stop_bpstat
);
431 if (call_thread
!= NULL
)
432 call_thread
->control
.in_infcall
= saved_in_infcall
;
437 /* A cleanup function that calls delete_std_terminate_breakpoint. */
439 cleanup_delete_std_terminate_breakpoint (void *ignore
)
441 delete_std_terminate_breakpoint ();
444 /* All this stuff with a dummy frame may seem unnecessarily complicated
445 (why not just save registers in GDB?). The purpose of pushing a dummy
446 frame which looks just like a real frame is so that if you call a
447 function and then hit a breakpoint (get a signal, etc), "backtrace"
448 will look right. Whether the backtrace needs to actually show the
449 stack at the time the inferior function was called is debatable, but
450 it certainly needs to not display garbage. So if you are contemplating
451 making dummy frames be different from normal frames, consider that. */
453 /* Perform a function call in the inferior.
454 ARGS is a vector of values of arguments (NARGS of them).
455 FUNCTION is a value, the function to be called.
456 Returns a value representing what the function returned.
457 May fail to return, if a breakpoint or signal is hit
458 during the execution of the function.
460 ARGS is modified to contain coerced values. */
463 call_function_by_hand (struct value
*function
, int nargs
, struct value
**args
)
466 struct type
*values_type
, *target_values_type
;
467 unsigned char struct_return
= 0, hidden_first_param_p
= 0;
468 CORE_ADDR struct_addr
= 0;
469 struct infcall_control_state
*inf_status
;
470 struct cleanup
*inf_status_cleanup
;
471 struct infcall_suspend_state
*caller_state
;
474 struct type
*ftype
= check_typedef (value_type (function
));
476 struct frame_id dummy_id
;
477 struct cleanup
*args_cleanup
;
478 struct frame_info
*frame
;
479 struct gdbarch
*gdbarch
;
480 struct cleanup
*terminate_bp_cleanup
;
481 ptid_t call_thread_ptid
;
482 struct gdb_exception e
;
483 char name_buf
[RAW_FUNCTION_ADDRESS_SIZE
];
485 if (TYPE_CODE (ftype
) == TYPE_CODE_PTR
)
486 ftype
= check_typedef (TYPE_TARGET_TYPE (ftype
));
488 if (!target_has_execution
)
491 if (get_traceframe_number () >= 0)
492 error (_("May not call functions while looking at trace frames."));
494 if (execution_direction
== EXEC_REVERSE
)
495 error (_("Cannot call functions in reverse mode."));
497 frame
= get_current_frame ();
498 gdbarch
= get_frame_arch (frame
);
500 if (!gdbarch_push_dummy_call_p (gdbarch
))
501 error (_("This target does not support function calls."));
503 /* A cleanup for the inferior status.
504 This is only needed while we're preparing the inferior function call. */
505 inf_status
= save_infcall_control_state ();
507 = make_cleanup_restore_infcall_control_state (inf_status
);
509 /* Save the caller's registers and other state associated with the
510 inferior itself so that they can be restored once the
511 callee returns. To allow nested calls the registers are (further
512 down) pushed onto a dummy frame stack. Include a cleanup (which
513 is tossed once the regcache has been pushed). */
514 caller_state
= save_infcall_suspend_state ();
515 make_cleanup_restore_infcall_suspend_state (caller_state
);
517 /* Ensure that the initial SP is correctly aligned. */
519 CORE_ADDR old_sp
= get_frame_sp (frame
);
521 if (gdbarch_frame_align_p (gdbarch
))
523 sp
= gdbarch_frame_align (gdbarch
, old_sp
);
524 /* NOTE: cagney/2003-08-13: Skip the "red zone". For some
525 ABIs, a function can use memory beyond the inner most stack
526 address. AMD64 called that region the "red zone". Skip at
527 least the "red zone" size before allocating any space on
529 if (gdbarch_inner_than (gdbarch
, 1, 2))
530 sp
-= gdbarch_frame_red_zone_size (gdbarch
);
532 sp
+= gdbarch_frame_red_zone_size (gdbarch
);
534 gdb_assert (sp
== gdbarch_frame_align (gdbarch
, sp
));
535 /* NOTE: cagney/2002-09-18:
537 On a RISC architecture, a void parameterless generic dummy
538 frame (i.e., no parameters, no result) typically does not
539 need to push anything the stack and hence can leave SP and
540 FP. Similarly, a frameless (possibly leaf) function does
541 not push anything on the stack and, hence, that too can
542 leave FP and SP unchanged. As a consequence, a sequence of
543 void parameterless generic dummy frame calls to frameless
544 functions will create a sequence of effectively identical
545 frames (SP, FP and TOS and PC the same). This, not
546 suprisingly, results in what appears to be a stack in an
547 infinite loop --- when GDB tries to find a generic dummy
548 frame on the internal dummy frame stack, it will always
551 To avoid this problem, the code below always grows the
552 stack. That way, two dummy frames can never be identical.
553 It does burn a few bytes of stack but that is a small price
557 if (gdbarch_inner_than (gdbarch
, 1, 2))
558 /* Stack grows down. */
559 sp
= gdbarch_frame_align (gdbarch
, old_sp
- 1);
561 /* Stack grows up. */
562 sp
= gdbarch_frame_align (gdbarch
, old_sp
+ 1);
564 /* SP may have underflown address zero here from OLD_SP. Memory access
565 functions will probably fail in such case but that is a target's
569 /* FIXME: cagney/2002-09-18: Hey, you loose!
571 Who knows how badly aligned the SP is!
573 If the generic dummy frame ends up empty (because nothing is
574 pushed) GDB won't be able to correctly perform back traces.
575 If a target is having trouble with backtraces, first thing to
576 do is add FRAME_ALIGN() to the architecture vector. If that
577 fails, try dummy_id().
579 If the ABI specifies a "Red Zone" (see the doco) the code
580 below will quietly trash it. */
584 funaddr
= find_function_addr (function
, &values_type
);
586 values_type
= builtin_type (gdbarch
)->builtin_int
;
588 CHECK_TYPEDEF (values_type
);
590 /* Are we returning a value using a structure return (passing a
591 hidden argument pointing to storage) or a normal value return?
592 There are two cases: language-mandated structure return and
593 target ABI structure return. The variable STRUCT_RETURN only
594 describes the latter. The language version is handled by passing
595 the return location as the first parameter to the function,
596 even preceding "this". This is different from the target
597 ABI version, which is target-specific; for instance, on ia64
598 the first argument is passed in out0 but the hidden structure
599 return pointer would normally be passed in r8. */
601 if (gdbarch_return_in_first_hidden_param_p (gdbarch
, values_type
))
603 hidden_first_param_p
= 1;
605 /* Tell the target specific argument pushing routine not to
607 target_values_type
= builtin_type (gdbarch
)->builtin_void
;
611 struct_return
= using_struct_return (gdbarch
, function
, values_type
);
612 target_values_type
= values_type
;
615 /* Determine the location of the breakpoint (and possibly other
616 stuff) that the called function will return to. The SPARC, for a
617 function returning a structure or union, needs to make space for
618 not just the breakpoint but also an extra word containing the
619 size (?) of the structure being passed. */
621 /* The actual breakpoint (at BP_ADDR) is inserted separatly so there
622 is no need to write that out. */
624 switch (gdbarch_call_dummy_location (gdbarch
))
627 sp
= push_dummy_code (gdbarch
, sp
, funaddr
,
628 args
, nargs
, target_values_type
,
629 &real_pc
, &bp_addr
, get_current_regcache ());
633 CORE_ADDR dummy_addr
;
636 dummy_addr
= entry_point_address ();
637 /* A call dummy always consists of just a single breakpoint, so
638 its address is the same as the address of the dummy. */
639 bp_addr
= dummy_addr
;
643 internal_error (__FILE__
, __LINE__
, _("bad switch"));
646 if (nargs
< TYPE_NFIELDS (ftype
))
647 error (_("Too few arguments in function call."));
652 for (i
= nargs
- 1; i
>= 0; i
--)
655 struct type
*param_type
;
657 /* FIXME drow/2002-05-31: Should just always mark methods as
658 prototyped. Can we respect TYPE_VARARGS? Probably not. */
659 if (TYPE_CODE (ftype
) == TYPE_CODE_METHOD
)
661 else if (i
< TYPE_NFIELDS (ftype
))
662 prototyped
= TYPE_PROTOTYPED (ftype
);
666 if (i
< TYPE_NFIELDS (ftype
))
667 param_type
= TYPE_FIELD_TYPE (ftype
, i
);
671 args
[i
] = value_arg_coerce (gdbarch
, args
[i
],
672 param_type
, prototyped
, &sp
);
674 if (param_type
!= NULL
&& language_pass_by_reference (param_type
))
675 args
[i
] = value_addr (args
[i
]);
679 /* Reserve space for the return structure to be written on the
680 stack, if necessary. Make certain that the value is correctly
683 if (struct_return
|| hidden_first_param_p
)
685 int len
= TYPE_LENGTH (values_type
);
687 if (gdbarch_inner_than (gdbarch
, 1, 2))
689 /* Stack grows downward. Align STRUCT_ADDR and SP after
690 making space for the return value. */
692 if (gdbarch_frame_align_p (gdbarch
))
693 sp
= gdbarch_frame_align (gdbarch
, sp
);
698 /* Stack grows upward. Align the frame, allocate space, and
699 then again, re-align the frame??? */
700 if (gdbarch_frame_align_p (gdbarch
))
701 sp
= gdbarch_frame_align (gdbarch
, sp
);
704 if (gdbarch_frame_align_p (gdbarch
))
705 sp
= gdbarch_frame_align (gdbarch
, sp
);
709 if (hidden_first_param_p
)
711 struct value
**new_args
;
713 /* Add the new argument to the front of the argument list. */
714 new_args
= xmalloc (sizeof (struct value
*) * (nargs
+ 1));
715 new_args
[0] = value_from_pointer (lookup_pointer_type (values_type
),
717 memcpy (&new_args
[1], &args
[0], sizeof (struct value
*) * nargs
);
720 args_cleanup
= make_cleanup (xfree
, args
);
723 args_cleanup
= make_cleanup (null_cleanup
, NULL
);
725 /* Create the dummy stack frame. Pass in the call dummy address as,
726 presumably, the ABI code knows where, in the call dummy, the
727 return address should be pointed. */
728 sp
= gdbarch_push_dummy_call (gdbarch
, function
, get_current_regcache (),
729 bp_addr
, nargs
, args
,
730 sp
, struct_return
, struct_addr
);
732 do_cleanups (args_cleanup
);
734 /* Set up a frame ID for the dummy frame so we can pass it to
735 set_momentary_breakpoint. We need to give the breakpoint a frame
736 ID so that the breakpoint code can correctly re-identify the
738 /* Sanity. The exact same SP value is returned by PUSH_DUMMY_CALL,
739 saved as the dummy-frame TOS, and used by dummy_id to form
740 the frame ID's stack address. */
741 dummy_id
= frame_id_build (sp
, bp_addr
);
743 /* Create a momentary breakpoint at the return address of the
744 inferior. That way it breaks when it returns. */
747 struct breakpoint
*bpt
;
748 struct symtab_and_line sal
;
750 init_sal (&sal
); /* initialize to zeroes */
751 sal
.pspace
= current_program_space
;
753 sal
.section
= find_pc_overlay (sal
.pc
);
754 /* Sanity. The exact same SP value is returned by
755 PUSH_DUMMY_CALL, saved as the dummy-frame TOS, and used by
756 dummy_id to form the frame ID's stack address. */
757 bpt
= set_momentary_breakpoint (gdbarch
, sal
, dummy_id
, bp_call_dummy
);
759 /* set_momentary_breakpoint invalidates FRAME. */
762 bpt
->disposition
= disp_del
;
765 /* Create a breakpoint in std::terminate.
766 If a C++ exception is raised in the dummy-frame, and the
767 exception handler is (normally, and expected to be) out-of-frame,
768 the default C++ handler will (wrongly) be called in an inferior
769 function call. This is wrong, as an exception can be normally
770 and legally handled out-of-frame. The confines of the dummy frame
771 prevent the unwinder from finding the correct handler (or any
772 handler, unless it is in-frame). The default handler calls
773 std::terminate. This will kill the inferior. Assert that
774 terminate should never be called in an inferior function
775 call. Place a momentary breakpoint in the std::terminate function
776 and if triggered in the call, rewind. */
777 if (unwind_on_terminating_exception_p
)
778 set_std_terminate_breakpoint ();
780 /* Everything's ready, push all the info needed to restore the
781 caller (and identify the dummy-frame) onto the dummy-frame
783 dummy_frame_push (caller_state
, &dummy_id
);
785 /* Discard both inf_status and caller_state cleanups.
786 From this point on we explicitly restore the associated state
788 discard_cleanups (inf_status_cleanup
);
790 /* Register a clean-up for unwind_on_terminating_exception_breakpoint. */
791 terminate_bp_cleanup
= make_cleanup (cleanup_delete_std_terminate_breakpoint
,
794 /* - SNIP - SNIP - SNIP - SNIP - SNIP - SNIP - SNIP - SNIP - SNIP -
795 If you're looking to implement asynchronous dummy-frames, then
796 just below is the place to chop this function in two.. */
798 /* TP is invalid after run_inferior_call returns, so enclose this
799 in a block so that it's only in scope during the time it's valid. */
801 struct thread_info
*tp
= inferior_thread ();
803 /* Save this thread's ptid, we need it later but the thread
805 call_thread_ptid
= tp
->ptid
;
807 /* Run the inferior until it stops. */
809 e
= run_inferior_call (tp
, real_pc
);
812 /* Rethrow an error if we got one trying to run the inferior. */
816 const char *name
= get_function_name (funaddr
,
817 name_buf
, sizeof (name_buf
));
819 discard_infcall_control_state (inf_status
);
821 /* We could discard the dummy frame here if the program exited,
822 but it will get garbage collected the next time the program is
828 throw_error (e
.error
, _("%s\n\
829 An error occurred while in a function called from GDB.\n\
830 Evaluation of the expression containing the function\n\
831 (%s) will be abandoned.\n\
832 When the function is done executing, GDB will silently stop."),
840 /* If the program has exited, or we stopped at a different thread,
841 exit and inform the user. */
843 if (! target_has_execution
)
845 const char *name
= get_function_name (funaddr
,
846 name_buf
, sizeof (name_buf
));
848 /* If we try to restore the inferior status,
849 we'll crash as the inferior is no longer running. */
850 discard_infcall_control_state (inf_status
);
852 /* We could discard the dummy frame here given that the program exited,
853 but it will get garbage collected the next time the program is
856 error (_("The program being debugged exited while in a function "
858 "Evaluation of the expression containing the function\n"
859 "(%s) will be abandoned."),
863 if (! ptid_equal (call_thread_ptid
, inferior_ptid
))
865 const char *name
= get_function_name (funaddr
,
866 name_buf
, sizeof (name_buf
));
868 /* We've switched threads. This can happen if another thread gets a
869 signal or breakpoint while our thread was running.
870 There's no point in restoring the inferior status,
871 we're in a different thread. */
872 discard_infcall_control_state (inf_status
);
873 /* Keep the dummy frame record, if the user switches back to the
874 thread with the hand-call, we'll need it. */
875 if (stopped_by_random_signal
)
877 The program received a signal in another thread while\n\
878 making a function call from GDB.\n\
879 Evaluation of the expression containing the function\n\
880 (%s) will be abandoned.\n\
881 When the function is done executing, GDB will silently stop."),
885 The program stopped in another thread while making a function call from GDB.\n\
886 Evaluation of the expression containing the function\n\
887 (%s) will be abandoned.\n\
888 When the function is done executing, GDB will silently stop."),
892 if (stopped_by_random_signal
|| stop_stack_dummy
!= STOP_STACK_DUMMY
)
894 const char *name
= get_function_name (funaddr
,
895 name_buf
, sizeof (name_buf
));
897 if (stopped_by_random_signal
)
899 /* We stopped inside the FUNCTION because of a random
900 signal. Further execution of the FUNCTION is not
903 if (unwind_on_signal_p
)
905 /* The user wants the context restored. */
907 /* We must get back to the frame we were before the
909 dummy_frame_pop (dummy_id
);
911 /* We also need to restore inferior status to that before the
913 restore_infcall_control_state (inf_status
);
915 /* FIXME: Insert a bunch of wrap_here; name can be very
916 long if it's a C++ name with arguments and stuff. */
918 The program being debugged was signaled while in a function called from GDB.\n\
919 GDB has restored the context to what it was before the call.\n\
920 To change this behavior use \"set unwindonsignal off\".\n\
921 Evaluation of the expression containing the function\n\
922 (%s) will be abandoned."),
927 /* The user wants to stay in the frame where we stopped
929 Discard inferior status, we're not at the same point
931 discard_infcall_control_state (inf_status
);
933 /* FIXME: Insert a bunch of wrap_here; name can be very
934 long if it's a C++ name with arguments and stuff. */
936 The program being debugged was signaled while in a function called from GDB.\n\
937 GDB remains in the frame where the signal was received.\n\
938 To change this behavior use \"set unwindonsignal on\".\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."),
946 if (stop_stack_dummy
== STOP_STD_TERMINATE
)
948 /* We must get back to the frame we were before the dummy
950 dummy_frame_pop (dummy_id
);
952 /* We also need to restore inferior status to that before
954 restore_infcall_control_state (inf_status
);
957 The program being debugged entered a std::terminate call, most likely\n\
958 caused by an unhandled C++ exception. GDB blocked this call in order\n\
959 to prevent the program from being terminated, and has restored the\n\
960 context to its original state before the call.\n\
961 To change this behaviour use \"set unwind-on-terminating-exception off\".\n\
962 Evaluation of the expression containing the function (%s)\n\
963 will be abandoned."),
966 else if (stop_stack_dummy
== STOP_NONE
)
969 /* We hit a breakpoint inside the FUNCTION.
970 Keep the dummy frame, the user may want to examine its state.
971 Discard inferior status, we're not at the same point
973 discard_infcall_control_state (inf_status
);
975 /* The following error message used to say "The expression
976 which contained the function call has been discarded."
977 It is a hard concept to explain in a few words. Ideally,
978 GDB would be able to resume evaluation of the expression
979 when the function finally is done executing. Perhaps
980 someday this will be implemented (it would not be easy). */
981 /* FIXME: Insert a bunch of wrap_here; name can be very long if it's
982 a C++ name with arguments and stuff. */
984 The program being debugged stopped while in a function called from GDB.\n\
985 Evaluation of the expression containing the function\n\
986 (%s) will be abandoned.\n\
987 When the function is done executing, GDB will silently stop."),
991 /* The above code errors out, so ... */
992 internal_error (__FILE__
, __LINE__
, _("... should not be here"));
995 do_cleanups (terminate_bp_cleanup
);
997 /* If we get here the called FUNCTION ran to completion,
998 and the dummy frame has already been popped. */
1001 struct address_space
*aspace
= get_regcache_aspace (stop_registers
);
1002 struct regcache
*retbuf
= regcache_xmalloc (gdbarch
, aspace
);
1003 struct cleanup
*retbuf_cleanup
= make_cleanup_regcache_xfree (retbuf
);
1004 struct value
*retval
= NULL
;
1006 regcache_cpy_no_passthrough (retbuf
, stop_registers
);
1008 /* Inferior call is successful. Restore the inferior status.
1009 At this stage, leave the RETBUF alone. */
1010 restore_infcall_control_state (inf_status
);
1012 /* Figure out the value returned by the function. */
1013 retval
= allocate_value (values_type
);
1015 if (hidden_first_param_p
)
1016 read_value_memory (retval
, 0, 1, struct_addr
,
1017 value_contents_raw (retval
),
1018 TYPE_LENGTH (values_type
));
1019 else if (TYPE_CODE (target_values_type
) != TYPE_CODE_VOID
)
1021 /* If the function returns void, don't bother fetching the
1023 switch (gdbarch_return_value (gdbarch
, function
, target_values_type
,
1026 case RETURN_VALUE_REGISTER_CONVENTION
:
1027 case RETURN_VALUE_ABI_RETURNS_ADDRESS
:
1028 case RETURN_VALUE_ABI_PRESERVES_ADDRESS
:
1029 gdbarch_return_value (gdbarch
, function
, values_type
,
1030 retbuf
, value_contents_raw (retval
), NULL
);
1032 case RETURN_VALUE_STRUCT_CONVENTION
:
1033 read_value_memory (retval
, 0, 1, struct_addr
,
1034 value_contents_raw (retval
),
1035 TYPE_LENGTH (values_type
));
1040 do_cleanups (retbuf_cleanup
);
1042 gdb_assert (retval
);
1048 /* Provide a prototype to silence -Wmissing-prototypes. */
1049 void _initialize_infcall (void);
1052 _initialize_infcall (void)
1054 add_setshow_boolean_cmd ("coerce-float-to-double", class_obscure
,
1055 &coerce_float_to_double_p
, _("\
1056 Set coercion of floats to doubles when calling functions."), _("\
1057 Show coercion of floats to doubles when calling functions"), _("\
1058 Variables of type float should generally be converted to doubles before\n\
1059 calling an unprototyped function, and left alone when calling a prototyped\n\
1060 function. However, some older debug info formats do not provide enough\n\
1061 information to determine that a function is prototyped. If this flag is\n\
1062 set, GDB will perform the conversion for a function it considers\n\
1064 The default is to perform the conversion.\n"),
1066 show_coerce_float_to_double_p
,
1067 &setlist
, &showlist
);
1069 add_setshow_boolean_cmd ("unwindonsignal", no_class
,
1070 &unwind_on_signal_p
, _("\
1071 Set unwinding of stack if a signal is received while in a call dummy."), _("\
1072 Show unwinding of stack if a signal is received while in a call dummy."), _("\
1073 The unwindonsignal lets the user determine what gdb should do if a signal\n\
1074 is received while in a function called from gdb (call dummy). If set, gdb\n\
1075 unwinds the stack and restore the context to what as it was before the call.\n\
1076 The default is to stop in the frame where the signal was received."),
1078 show_unwind_on_signal_p
,
1079 &setlist
, &showlist
);
1081 add_setshow_boolean_cmd ("unwind-on-terminating-exception", no_class
,
1082 &unwind_on_terminating_exception_p
, _("\
1083 Set unwinding of stack if std::terminate is called while in call dummy."), _("\
1084 Show unwinding of stack if std::terminate() is called while in a call dummy."),
1086 The unwind on terminating exception flag lets the user determine\n\
1087 what gdb should do if a std::terminate() call is made from the\n\
1088 default exception handler. If set, gdb unwinds the stack and restores\n\
1089 the context to what it was before the call. If unset, gdb allows the\n\
1090 std::terminate call to proceed.\n\
1091 The default is to unwind the frame."),
1093 show_unwind_on_terminating_exception_p
,
1094 &setlist
, &showlist
);