1 /* Perform an inferior function call, for GDB, the GNU debugger.
3 Copyright 1986, 1987, 1988, 1989, 1990, 1991, 1992, 1993, 1994,
4 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005
5 Free Software Foundation, Inc.
7 This file is part of GDB.
9 This program is free software; you can redistribute it and/or modify
10 it under the terms of the GNU General Public License as published by
11 the Free Software Foundation; either version 2 of the License, or
12 (at your option) any later version.
14 This program is distributed in the hope that it will be useful,
15 but WITHOUT ANY WARRANTY; without even the implied warranty of
16 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 GNU General Public License for more details.
19 You should have received a copy of the GNU General Public License
20 along with this program; if not, write to the Free Software
21 Foundation, Inc., 59 Temple Place - Suite 330,
22 Boston, MA 02111-1307, USA. */
25 #include "breakpoint.h"
29 #include "gdb_assert.h"
36 #include "gdb_string.h"
38 #include "dummy-frame.h"
40 /* NOTE: cagney/2003-04-16: What's the future of this code?
42 GDB needs an asynchronous expression evaluator, that means an
43 asynchronous inferior function call implementation, and that in
44 turn means restructuring the code so that it is event driven. */
46 /* How you should pass arguments to a function depends on whether it
47 was defined in K&R style or prototype style. If you define a
48 function using the K&R syntax that takes a `float' argument, then
49 callers must pass that argument as a `double'. If you define the
50 function using the prototype syntax, then you must pass the
51 argument as a `float', with no promotion.
53 Unfortunately, on certain older platforms, the debug info doesn't
54 indicate reliably how each function was defined. A function type's
55 TYPE_FLAG_PROTOTYPED flag may be clear, even if the function was
56 defined in prototype style. When calling a function whose
57 TYPE_FLAG_PROTOTYPED flag is clear, GDB consults this flag to
60 For modern targets, it is proper to assume that, if the prototype
61 flag is clear, that can be trusted: `float' arguments should be
62 promoted to `double'. For some older targets, if the prototype
63 flag is clear, that doesn't tell us anything. The default is to
64 trust the debug information; the user can override this behavior
65 with "set coerce-float-to-double 0". */
67 static int coerce_float_to_double_p
= 1;
69 show_coerce_float_to_double_p (struct ui_file
*file
, int from_tty
,
70 struct cmd_list_element
*c
, const char *value
)
72 fprintf_filtered (file
, _("\
73 Coercion of floats to doubles when calling functions is %s.\n"),
77 /* This boolean tells what gdb should do if a signal is received while
78 in a function called from gdb (call dummy). If set, gdb unwinds
79 the stack and restore the context to what as it was before the
82 The default is to stop in the frame where the signal was received. */
84 int unwind_on_signal_p
= 0;
86 show_unwind_on_signal_p (struct ui_file
*file
, int from_tty
,
87 struct cmd_list_element
*c
, const char *value
)
89 fprintf_filtered (file
, _("\
90 Unwinding of stack if a signal is received while in a call dummy is %s.\n"),
95 /* Perform the standard coercions that are specified
96 for arguments to be passed to C functions.
98 If PARAM_TYPE is non-NULL, it is the expected parameter type.
99 IS_PROTOTYPED is non-zero if the function declaration is prototyped. */
101 static struct value
*
102 value_arg_coerce (struct value
*arg
, struct type
*param_type
,
105 struct type
*arg_type
= check_typedef (value_type (arg
));
107 = param_type
? check_typedef (param_type
) : arg_type
;
109 switch (TYPE_CODE (type
))
112 if (TYPE_CODE (arg_type
) != TYPE_CODE_REF
113 && TYPE_CODE (arg_type
) != TYPE_CODE_PTR
)
115 arg
= value_addr (arg
);
116 deprecated_set_value_type (arg
, param_type
);
124 /* If we don't have a prototype, coerce to integer type if necessary. */
127 if (TYPE_LENGTH (type
) < TYPE_LENGTH (builtin_type_int
))
128 type
= builtin_type_int
;
130 /* Currently all target ABIs require at least the width of an integer
131 type for an argument. We may have to conditionalize the following
132 type coercion for future targets. */
133 if (TYPE_LENGTH (type
) < TYPE_LENGTH (builtin_type_int
))
134 type
= builtin_type_int
;
137 if (!is_prototyped
&& coerce_float_to_double_p
)
139 if (TYPE_LENGTH (type
) < TYPE_LENGTH (builtin_type_double
))
140 type
= builtin_type_double
;
141 else if (TYPE_LENGTH (type
) > TYPE_LENGTH (builtin_type_double
))
142 type
= builtin_type_long_double
;
146 type
= lookup_pointer_type (type
);
148 case TYPE_CODE_ARRAY
:
149 /* Arrays are coerced to pointers to their first element, unless
150 they are vectors, in which case we want to leave them alone,
151 because they are passed by value. */
152 if (current_language
->c_style_arrays
)
153 if (!TYPE_VECTOR (type
))
154 type
= lookup_pointer_type (TYPE_TARGET_TYPE (type
));
156 case TYPE_CODE_UNDEF
:
158 case TYPE_CODE_STRUCT
:
159 case TYPE_CODE_UNION
:
162 case TYPE_CODE_RANGE
:
163 case TYPE_CODE_STRING
:
164 case TYPE_CODE_BITSTRING
:
165 case TYPE_CODE_ERROR
:
166 case TYPE_CODE_MEMBER
:
167 case TYPE_CODE_METHOD
:
168 case TYPE_CODE_COMPLEX
:
173 return value_cast (type
, arg
);
176 /* Determine a function's address and its return type from its value.
177 Calls error() if the function is not valid for calling. */
180 find_function_addr (struct value
*function
, struct type
**retval_type
)
182 struct type
*ftype
= check_typedef (value_type (function
));
183 enum type_code code
= TYPE_CODE (ftype
);
184 struct type
*value_type
;
187 /* If it's a member function, just look at the function
190 /* Determine address to call. */
191 if (code
== TYPE_CODE_FUNC
|| code
== TYPE_CODE_METHOD
)
193 funaddr
= VALUE_ADDRESS (function
);
194 value_type
= TYPE_TARGET_TYPE (ftype
);
196 else if (code
== TYPE_CODE_PTR
)
198 funaddr
= value_as_address (function
);
199 ftype
= check_typedef (TYPE_TARGET_TYPE (ftype
));
200 if (TYPE_CODE (ftype
) == TYPE_CODE_FUNC
201 || TYPE_CODE (ftype
) == TYPE_CODE_METHOD
)
203 funaddr
= gdbarch_convert_from_func_ptr_addr (current_gdbarch
,
206 value_type
= TYPE_TARGET_TYPE (ftype
);
209 value_type
= builtin_type_int
;
211 else if (code
== TYPE_CODE_INT
)
213 /* Handle the case of functions lacking debugging info.
214 Their values are characters since their addresses are char */
215 if (TYPE_LENGTH (ftype
) == 1)
216 funaddr
= value_as_address (value_addr (function
));
218 /* Handle integer used as address of a function. */
219 funaddr
= (CORE_ADDR
) value_as_long (function
);
221 value_type
= builtin_type_int
;
224 error (_("Invalid data type for function to be called."));
226 if (retval_type
!= NULL
)
227 *retval_type
= value_type
;
228 return funaddr
+ DEPRECATED_FUNCTION_START_OFFSET
;
231 /* Call breakpoint_auto_delete on the current contents of the bpstat
232 pointed to by arg (which is really a bpstat *). */
235 breakpoint_auto_delete_contents (void *arg
)
237 breakpoint_auto_delete (*(bpstat
*) arg
);
241 generic_push_dummy_code (struct gdbarch
*gdbarch
,
242 CORE_ADDR sp
, CORE_ADDR funaddr
, int using_gcc
,
243 struct value
**args
, int nargs
,
244 struct type
*value_type
,
245 CORE_ADDR
*real_pc
, CORE_ADDR
*bp_addr
)
247 /* Something here to findout the size of a breakpoint and then
248 allocate space for it on the stack. */
250 /* This code assumes frame align. */
251 gdb_assert (gdbarch_frame_align_p (gdbarch
));
252 /* Force the stack's alignment. The intent is to ensure that the SP
253 is aligned to at least a breakpoint instruction's boundary. */
254 sp
= gdbarch_frame_align (gdbarch
, sp
);
255 /* Allocate space for, and then position the breakpoint on the
257 if (gdbarch_inner_than (gdbarch
, 1, 2))
260 gdbarch_breakpoint_from_pc (gdbarch
, &bppc
, &bplen
);
261 sp
= gdbarch_frame_align (gdbarch
, sp
- bplen
);
263 /* Should the breakpoint size/location be re-computed here? */
268 gdbarch_breakpoint_from_pc (gdbarch
, bp_addr
, &bplen
);
269 sp
= gdbarch_frame_align (gdbarch
, sp
+ bplen
);
271 /* Inferior resumes at the function entry point. */
272 (*real_pc
) = funaddr
;
276 /* For CALL_DUMMY_ON_STACK, push a breakpoint sequence that the called
277 function returns to. */
280 push_dummy_code (struct gdbarch
*gdbarch
,
281 CORE_ADDR sp
, CORE_ADDR funaddr
, int using_gcc
,
282 struct value
**args
, int nargs
,
283 struct type
*value_type
,
284 CORE_ADDR
*real_pc
, CORE_ADDR
*bp_addr
)
286 if (gdbarch_push_dummy_code_p (gdbarch
))
287 return gdbarch_push_dummy_code (gdbarch
, sp
, funaddr
, using_gcc
,
288 args
, nargs
, value_type
, real_pc
, bp_addr
);
290 return generic_push_dummy_code (gdbarch
, sp
, funaddr
, using_gcc
,
291 args
, nargs
, value_type
, real_pc
, bp_addr
);
294 /* All this stuff with a dummy frame may seem unnecessarily complicated
295 (why not just save registers in GDB?). The purpose of pushing a dummy
296 frame which looks just like a real frame is so that if you call a
297 function and then hit a breakpoint (get a signal, etc), "backtrace"
298 will look right. Whether the backtrace needs to actually show the
299 stack at the time the inferior function was called is debatable, but
300 it certainly needs to not display garbage. So if you are contemplating
301 making dummy frames be different from normal frames, consider that. */
303 /* Perform a function call in the inferior.
304 ARGS is a vector of values of arguments (NARGS of them).
305 FUNCTION is a value, the function to be called.
306 Returns a value representing what the function returned.
307 May fail to return, if a breakpoint or signal is hit
308 during the execution of the function.
310 ARGS is modified to contain coerced values. */
313 call_function_by_hand (struct value
*function
, int nargs
, struct value
**args
)
316 CORE_ADDR dummy_addr
;
317 struct type
*values_type
;
318 unsigned char struct_return
;
319 CORE_ADDR struct_addr
= 0;
320 struct regcache
*retbuf
;
321 struct cleanup
*retbuf_cleanup
;
322 struct inferior_status
*inf_status
;
323 struct cleanup
*inf_status_cleanup
;
325 int using_gcc
; /* Set to version of gcc in use, or zero if not gcc */
327 struct type
*ftype
= check_typedef (value_type (function
));
329 struct regcache
*caller_regcache
;
330 struct cleanup
*caller_regcache_cleanup
;
331 struct frame_id dummy_id
;
333 if (!target_has_execution
)
336 /* Create a cleanup chain that contains the retbuf (buffer
337 containing the register values). This chain is create BEFORE the
338 inf_status chain so that the inferior status can cleaned up
339 (restored or discarded) without having the retbuf freed. */
340 retbuf
= regcache_xmalloc (current_gdbarch
);
341 retbuf_cleanup
= make_cleanup_regcache_xfree (retbuf
);
343 /* A cleanup for the inferior status. Create this AFTER the retbuf
344 so that this can be discarded or applied without interfering with
346 inf_status
= save_inferior_status (1);
347 inf_status_cleanup
= make_cleanup_restore_inferior_status (inf_status
);
349 /* Save the caller's registers so that they can be restored once the
350 callee returns. To allow nested calls the registers are (further
351 down) pushed onto a dummy frame stack. Include a cleanup (which
352 is tossed once the regcache has been pushed). */
353 caller_regcache
= frame_save_as_regcache (get_current_frame ());
354 caller_regcache_cleanup
= make_cleanup_regcache_xfree (caller_regcache
);
356 /* Ensure that the initial SP is correctly aligned. */
358 CORE_ADDR old_sp
= read_sp ();
359 if (gdbarch_frame_align_p (current_gdbarch
))
361 sp
= gdbarch_frame_align (current_gdbarch
, old_sp
);
362 /* NOTE: cagney/2003-08-13: Skip the "red zone". For some
363 ABIs, a function can use memory beyond the inner most stack
364 address. AMD64 called that region the "red zone". Skip at
365 least the "red zone" size before allocating any space on
367 if (INNER_THAN (1, 2))
368 sp
-= gdbarch_frame_red_zone_size (current_gdbarch
);
370 sp
+= gdbarch_frame_red_zone_size (current_gdbarch
);
372 gdb_assert (sp
== gdbarch_frame_align (current_gdbarch
, sp
));
373 /* NOTE: cagney/2002-09-18:
375 On a RISC architecture, a void parameterless generic dummy
376 frame (i.e., no parameters, no result) typically does not
377 need to push anything the stack and hence can leave SP and
378 FP. Similarly, a frameless (possibly leaf) function does
379 not push anything on the stack and, hence, that too can
380 leave FP and SP unchanged. As a consequence, a sequence of
381 void parameterless generic dummy frame calls to frameless
382 functions will create a sequence of effectively identical
383 frames (SP, FP and TOS and PC the same). This, not
384 suprisingly, results in what appears to be a stack in an
385 infinite loop --- when GDB tries to find a generic dummy
386 frame on the internal dummy frame stack, it will always
389 To avoid this problem, the code below always grows the
390 stack. That way, two dummy frames can never be identical.
391 It does burn a few bytes of stack but that is a small price
395 if (INNER_THAN (1, 2))
396 /* Stack grows down. */
397 sp
= gdbarch_frame_align (current_gdbarch
, old_sp
- 1);
399 /* Stack grows up. */
400 sp
= gdbarch_frame_align (current_gdbarch
, old_sp
+ 1);
402 gdb_assert ((INNER_THAN (1, 2) && sp
<= old_sp
)
403 || (INNER_THAN (2, 1) && sp
>= old_sp
));
406 /* FIXME: cagney/2002-09-18: Hey, you loose!
408 Who knows how badly aligned the SP is!
410 If the generic dummy frame ends up empty (because nothing is
411 pushed) GDB won't be able to correctly perform back traces.
412 If a target is having trouble with backtraces, first thing to
413 do is add FRAME_ALIGN() to the architecture vector. If that
414 fails, try unwind_dummy_id().
416 If the ABI specifies a "Red Zone" (see the doco) the code
417 below will quietly trash it. */
421 funaddr
= find_function_addr (function
, &values_type
);
422 CHECK_TYPEDEF (values_type
);
425 struct block
*b
= block_for_pc (funaddr
);
426 /* If compiled without -g, assume GCC 2. */
427 using_gcc
= (b
== NULL
? 2 : BLOCK_GCC_COMPILED (b
));
430 /* Are we returning a value using a structure return or a normal
433 struct_return
= using_struct_return (values_type
, using_gcc
);
435 /* Determine the location of the breakpoint (and possibly other
436 stuff) that the called function will return to. The SPARC, for a
437 function returning a structure or union, needs to make space for
438 not just the breakpoint but also an extra word containing the
439 size (?) of the structure being passed. */
441 /* The actual breakpoint (at BP_ADDR) is inserted separatly so there
442 is no need to write that out. */
444 switch (CALL_DUMMY_LOCATION
)
447 /* "dummy_addr" is here just to keep old targets happy. New
448 targets return that same information via "sp" and "bp_addr". */
449 if (INNER_THAN (1, 2))
451 sp
= push_dummy_code (current_gdbarch
, sp
, funaddr
,
452 using_gcc
, args
, nargs
, values_type
,
459 sp
= push_dummy_code (current_gdbarch
, sp
, funaddr
,
460 using_gcc
, args
, nargs
, values_type
,
466 dummy_addr
= entry_point_address ();
467 /* Make certain that the address points at real code, and not a
468 function descriptor. */
469 dummy_addr
= gdbarch_convert_from_func_ptr_addr (current_gdbarch
,
472 /* A call dummy always consists of just a single breakpoint, so
473 it's address is the same as the address of the dummy. */
474 bp_addr
= dummy_addr
;
477 /* Some executables define a symbol __CALL_DUMMY_ADDRESS whose
478 address is the location where the breakpoint should be
479 placed. Once all targets are using the overhauled frame code
480 this can be deleted - ON_STACK is a better option. */
482 struct minimal_symbol
*sym
;
484 sym
= lookup_minimal_symbol ("__CALL_DUMMY_ADDRESS", NULL
, NULL
);
487 dummy_addr
= SYMBOL_VALUE_ADDRESS (sym
);
489 dummy_addr
= entry_point_address ();
490 /* Make certain that the address points at real code, and not
491 a function descriptor. */
492 dummy_addr
= gdbarch_convert_from_func_ptr_addr (current_gdbarch
,
495 /* A call dummy always consists of just a single breakpoint,
496 so it's address is the same as the address of the dummy. */
497 bp_addr
= dummy_addr
;
501 internal_error (__FILE__
, __LINE__
, _("bad switch"));
504 if (nargs
< TYPE_NFIELDS (ftype
))
505 error (_("too few arguments in function call"));
509 for (i
= nargs
- 1; i
>= 0; i
--)
512 struct type
*param_type
;
514 /* FIXME drow/2002-05-31: Should just always mark methods as
515 prototyped. Can we respect TYPE_VARARGS? Probably not. */
516 if (TYPE_CODE (ftype
) == TYPE_CODE_METHOD
)
518 else if (i
< TYPE_NFIELDS (ftype
))
519 prototyped
= TYPE_PROTOTYPED (ftype
);
523 if (i
< TYPE_NFIELDS (ftype
))
524 param_type
= TYPE_FIELD_TYPE (ftype
, i
);
528 args
[i
] = value_arg_coerce (args
[i
], param_type
, prototyped
);
530 /* elz: this code is to handle the case in which the function
531 to be called has a pointer to function as parameter and the
532 corresponding actual argument is the address of a function
533 and not a pointer to function variable. In aCC compiled
534 code, the calls through pointers to functions (in the body
535 of the function called by hand) are made via
536 $$dyncall_external which requires some registers setting,
537 this is taken care of if we call via a function pointer
538 variable, but not via a function address. In cc this is
543 if (param_type
!= NULL
&& TYPE_CODE (ftype
) != TYPE_CODE_METHOD
)
545 /* if this parameter is a pointer to function. */
546 if (TYPE_CODE (param_type
) == TYPE_CODE_PTR
)
547 if (TYPE_CODE (TYPE_TARGET_TYPE (param_type
)) == TYPE_CODE_FUNC
)
548 /* elz: FIXME here should go the test about the
549 compiler used to compile the target. We want to
550 issue the error message only if the compiler
551 used was HP's aCC. If we used HP's cc, then
552 there is no problem and no need to return at
554 /* Go see if the actual parameter is a variable of
555 type pointer to function or just a function. */
556 if (VALUE_LVAL (args
[i
]) == not_lval
)
559 /* NOTE: cagney/2005-01-02: THIS IS BOGUS. */
560 if (find_pc_partial_function ((CORE_ADDR
) value_contents (args
[i
])[0], &arg_name
, NULL
, NULL
))
562 You cannot use function <%s> as argument. \n\
563 You must use a pointer to function type variable. Command ignored."), arg_name
);
570 if (DEPRECATED_REG_STRUCT_HAS_ADDR_P ())
573 /* This is a machine like the sparc, where we may need to pass a
574 pointer to the structure, not the structure itself. */
575 for (i
= nargs
- 1; i
>= 0; i
--)
577 struct type
*arg_type
= check_typedef (value_type (args
[i
]));
578 if ((TYPE_CODE (arg_type
) == TYPE_CODE_STRUCT
579 || TYPE_CODE (arg_type
) == TYPE_CODE_UNION
580 || TYPE_CODE (arg_type
) == TYPE_CODE_ARRAY
581 || TYPE_CODE (arg_type
) == TYPE_CODE_STRING
582 || TYPE_CODE (arg_type
) == TYPE_CODE_BITSTRING
583 || TYPE_CODE (arg_type
) == TYPE_CODE_SET
584 || (TYPE_CODE (arg_type
) == TYPE_CODE_FLT
585 && TYPE_LENGTH (arg_type
) > 8)
587 && DEPRECATED_REG_STRUCT_HAS_ADDR (using_gcc
, arg_type
))
590 int len
; /* = TYPE_LENGTH (arg_type); */
592 arg_type
= check_typedef (value_enclosing_type (args
[i
]));
593 len
= TYPE_LENGTH (arg_type
);
596 if (INNER_THAN (1, 2))
598 /* stack grows downward */
600 /* ... so the address of the thing we push is the
601 stack pointer after we push it. */
606 /* The stack grows up, so the address of the thing
607 we push is the stack pointer before we push it. */
611 /* Push the structure. */
612 write_memory (addr
, value_contents_all (args
[i
]), len
);
613 /* The value we're going to pass is the address of the
614 thing we just pushed. */
615 /*args[i] = value_from_longest (lookup_pointer_type (values_type),
617 args
[i
] = value_from_pointer (lookup_pointer_type (arg_type
),
624 /* Reserve space for the return structure to be written on the
625 stack, if necessary. Make certain that the value is correctly
630 int len
= TYPE_LENGTH (values_type
);
631 if (INNER_THAN (1, 2))
633 /* Stack grows downward. Align STRUCT_ADDR and SP after
634 making space for the return value. */
636 if (gdbarch_frame_align_p (current_gdbarch
))
637 sp
= gdbarch_frame_align (current_gdbarch
, sp
);
642 /* Stack grows upward. Align the frame, allocate space, and
643 then again, re-align the frame??? */
644 if (gdbarch_frame_align_p (current_gdbarch
))
645 sp
= gdbarch_frame_align (current_gdbarch
, sp
);
648 if (gdbarch_frame_align_p (current_gdbarch
))
649 sp
= gdbarch_frame_align (current_gdbarch
, sp
);
653 /* Create the dummy stack frame. Pass in the call dummy address as,
654 presumably, the ABI code knows where, in the call dummy, the
655 return address should be pointed. */
656 if (gdbarch_push_dummy_call_p (current_gdbarch
))
657 /* When there is no push_dummy_call method, should this code
658 simply error out. That would the implementation of this method
659 for all ABIs (which is probably a good thing). */
660 sp
= gdbarch_push_dummy_call (current_gdbarch
, function
, current_regcache
,
661 bp_addr
, nargs
, args
, sp
, struct_return
,
663 else if (DEPRECATED_PUSH_ARGUMENTS_P ())
664 /* Keep old targets working. */
665 sp
= DEPRECATED_PUSH_ARGUMENTS (nargs
, args
, sp
, struct_return
,
668 error (_("This target does not support function calls"));
670 /* Set up a frame ID for the dummy frame so we can pass it to
671 set_momentary_breakpoint. We need to give the breakpoint a frame
672 ID so that the breakpoint code can correctly re-identify the
674 /* Sanity. The exact same SP value is returned by PUSH_DUMMY_CALL,
675 saved as the dummy-frame TOS, and used by unwind_dummy_id to form
676 the frame ID's stack address. */
677 dummy_id
= frame_id_build (sp
, bp_addr
);
679 /* Create a momentary breakpoint at the return address of the
680 inferior. That way it breaks when it returns. */
683 struct breakpoint
*bpt
;
684 struct symtab_and_line sal
;
685 init_sal (&sal
); /* initialize to zeroes */
687 sal
.section
= find_pc_overlay (sal
.pc
);
688 /* Sanity. The exact same SP value is returned by
689 PUSH_DUMMY_CALL, saved as the dummy-frame TOS, and used by
690 unwind_dummy_id to form the frame ID's stack address. */
691 bpt
= set_momentary_breakpoint (sal
, dummy_id
, bp_call_dummy
);
692 bpt
->disposition
= disp_del
;
695 /* Everything's ready, push all the info needed to restore the
696 caller (and identify the dummy-frame) onto the dummy-frame
698 dummy_frame_push (caller_regcache
, &dummy_id
);
699 discard_cleanups (caller_regcache_cleanup
);
701 /* - SNIP - SNIP - SNIP - SNIP - SNIP - SNIP - SNIP - SNIP - SNIP -
702 If you're looking to implement asynchronous dummy-frames, then
703 just below is the place to chop this function in two.. */
705 /* Now proceed, having reached the desired place. */
706 clear_proceed_status ();
708 /* Execute a "stack dummy", a piece of code stored in the stack by
709 the debugger to be executed in the inferior.
711 The dummy's frame is automatically popped whenever that break is
712 hit. If that is the first time the program stops,
713 call_function_by_hand returns to its caller with that frame
714 already gone and sets RC to 0.
716 Otherwise, set RC to a non-zero value. If the called function
717 receives a random signal, we do not allow the user to continue
718 executing it as this may not work. The dummy frame is poped and
719 we return 1. If we hit a breakpoint, we leave the frame in place
720 and return 2 (the frame will eventually be popped when we do hit
721 the dummy end breakpoint). */
724 struct cleanup
*old_cleanups
= make_cleanup (null_cleanup
, 0);
727 /* If all error()s out of proceed ended up calling normal_stop
728 (and perhaps they should; it already does in the special case
729 of error out of resume()), then we wouldn't need this. */
730 make_cleanup (breakpoint_auto_delete_contents
, &stop_bpstat
);
732 disable_watchpoints_before_interactive_call_start ();
733 proceed_to_finish
= 1; /* We want stop_registers, please... */
735 if (target_can_async_p ())
736 saved_async
= target_async_mask (0);
738 proceed (real_pc
, TARGET_SIGNAL_0
, 0);
741 target_async_mask (saved_async
);
743 enable_watchpoints_after_interactive_call_stop ();
745 discard_cleanups (old_cleanups
);
748 if (stopped_by_random_signal
|| !stop_stack_dummy
)
750 /* Find the name of the function we're about to complain about. */
751 const char *name
= NULL
;
753 struct symbol
*symbol
= find_pc_function (funaddr
);
755 name
= SYMBOL_PRINT_NAME (symbol
);
758 /* Try the minimal symbols. */
759 struct minimal_symbol
*msymbol
= lookup_minimal_symbol_by_pc (funaddr
);
761 name
= SYMBOL_PRINT_NAME (msymbol
);
765 /* Can't use a cleanup here. It is discarded, instead use
767 char *tmp
= xstrprintf ("at %s", hex_string (funaddr
));
768 char *a
= alloca (strlen (tmp
) + 1);
774 if (stopped_by_random_signal
)
776 /* We stopped inside the FUNCTION because of a random
777 signal. Further execution of the FUNCTION is not
780 if (unwind_on_signal_p
)
782 /* The user wants the context restored. */
784 /* We must get back to the frame we were before the
786 frame_pop (get_current_frame ());
788 /* FIXME: Insert a bunch of wrap_here; name can be very
789 long if it's a C++ name with arguments and stuff. */
791 The program being debugged was signaled while in a function called from GDB.\n\
792 GDB has restored the context to what it was before the call.\n\
793 To change this behavior use \"set unwindonsignal off\"\n\
794 Evaluation of the expression containing the function (%s) will be abandoned."),
799 /* The user wants to stay in the frame where we stopped
801 /* If we restored the inferior status (via the cleanup),
802 we would print a spurious error message (Unable to
803 restore previously selected frame), would write the
804 registers from the inf_status (which is wrong), and
805 would do other wrong things. */
806 discard_cleanups (inf_status_cleanup
);
807 discard_inferior_status (inf_status
);
808 /* FIXME: Insert a bunch of wrap_here; name can be very
809 long if it's a C++ name with arguments and stuff. */
811 The program being debugged was signaled while in a function called from GDB.\n\
812 GDB remains in the frame where the signal was received.\n\
813 To change this behavior use \"set unwindonsignal on\"\n\
814 Evaluation of the expression containing the function (%s) will be abandoned."),
819 if (!stop_stack_dummy
)
821 /* We hit a breakpoint inside the FUNCTION. */
822 /* If we restored the inferior status (via the cleanup), we
823 would print a spurious error message (Unable to restore
824 previously selected frame), would write the registers
825 from the inf_status (which is wrong), and would do other
827 discard_cleanups (inf_status_cleanup
);
828 discard_inferior_status (inf_status
);
829 /* The following error message used to say "The expression
830 which contained the function call has been discarded."
831 It is a hard concept to explain in a few words. Ideally,
832 GDB would be able to resume evaluation of the expression
833 when the function finally is done executing. Perhaps
834 someday this will be implemented (it would not be easy). */
835 /* FIXME: Insert a bunch of wrap_here; name can be very long if it's
836 a C++ name with arguments and stuff. */
838 The program being debugged stopped while in a function called from GDB.\n\
839 When the function (%s) is done executing, GDB will silently\n\
840 stop (instead of continuing to evaluate the expression containing\n\
841 the function call)."), name
);
844 /* The above code errors out, so ... */
845 internal_error (__FILE__
, __LINE__
, _("... should not be here"));
848 /* If we get here the called FUNCTION run to completion. */
850 /* On normal return, the stack dummy has been popped already. */
851 regcache_cpy_no_passthrough (retbuf
, stop_registers
);
853 /* Restore the inferior status, via its cleanup. At this stage,
854 leave the RETBUF alone. */
855 do_cleanups (inf_status_cleanup
);
857 /* Figure out the value returned by the function. */
859 struct value
*retval
= NULL
;
861 if (TYPE_CODE (values_type
) == TYPE_CODE_VOID
)
863 /* If the function returns void, don't bother fetching the
865 retval
= allocate_value (values_type
);
869 struct gdbarch
*arch
= current_gdbarch
;
871 switch (gdbarch_return_value (arch
, values_type
, NULL
, NULL
, NULL
))
873 case RETURN_VALUE_REGISTER_CONVENTION
:
874 case RETURN_VALUE_ABI_RETURNS_ADDRESS
:
875 case RETURN_VALUE_ABI_PRESERVES_ADDRESS
:
876 retval
= allocate_value (values_type
);
877 gdbarch_return_value (current_gdbarch
, values_type
, retbuf
,
878 value_contents_raw (retval
), NULL
);
880 case RETURN_VALUE_STRUCT_CONVENTION
:
881 retval
= value_at (values_type
, struct_addr
);
886 do_cleanups (retbuf_cleanup
);
894 /* Provide a prototype to silence -Wmissing-prototypes. */
895 void _initialize_infcall (void);
898 _initialize_infcall (void)
900 add_setshow_boolean_cmd ("coerce-float-to-double", class_obscure
,
901 &coerce_float_to_double_p
, _("\
902 Set coercion of floats to doubles when calling functions."), _("\
903 Show coercion of floats to doubles when calling functions"), _("\
904 Variables of type float should generally be converted to doubles before\n\
905 calling an unprototyped function, and left alone when calling a prototyped\n\
906 function. However, some older debug info formats do not provide enough\n\
907 information to determine that a function is prototyped. If this flag is\n\
908 set, GDB will perform the conversion for a function it considers\n\
910 The default is to perform the conversion.\n"),
912 show_coerce_float_to_double_p
,
913 &setlist
, &showlist
);
915 add_setshow_boolean_cmd ("unwindonsignal", no_class
,
916 &unwind_on_signal_p
, _("\
917 Set unwinding of stack if a signal is received while in a call dummy."), _("\
918 Show unwinding of stack if a signal is received while in a call dummy."), _("\
919 The unwindonsignal lets the user determine what gdb should do if a signal\n\
920 is received while in a function called from gdb (call dummy). If set, gdb\n\
921 unwinds the stack and restore the context to what as it was before the call.\n\
922 The default is to stop in the frame where the signal was received."),
924 show_unwind_on_signal_p
,
925 &setlist
, &showlist
);