1 /* Perform an inferior function call, for GDB, the GNU debugger.
3 Copyright (C) 1986, 1987, 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995,
4 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007,
5 2008, 2009, 2010, 2011 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 3 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, see <http://www.gnu.org/licenses/>. */
23 #include "breakpoint.h"
24 #include "tracepoint.h"
28 #include "gdb_assert.h"
35 #include "gdb_string.h"
37 #include "dummy-frame.h"
39 #include "gdbthread.h"
40 #include "exceptions.h"
42 /* If we can't find a function's name from its address,
43 we print this instead. */
44 #define RAW_FUNCTION_ADDRESS_FORMAT "at 0x%s"
45 #define RAW_FUNCTION_ADDRESS_SIZE (sizeof (RAW_FUNCTION_ADDRESS_FORMAT) \
46 + 2 * sizeof (CORE_ADDR))
48 /* NOTE: cagney/2003-04-16: What's the future of this code?
50 GDB needs an asynchronous expression evaluator, that means an
51 asynchronous inferior function call implementation, and that in
52 turn means restructuring the code so that it is event driven. */
54 /* How you should pass arguments to a function depends on whether it
55 was defined in K&R style or prototype style. If you define a
56 function using the K&R syntax that takes a `float' argument, then
57 callers must pass that argument as a `double'. If you define the
58 function using the prototype syntax, then you must pass the
59 argument as a `float', with no promotion.
61 Unfortunately, on certain older platforms, the debug info doesn't
62 indicate reliably how each function was defined. A function type's
63 TYPE_FLAG_PROTOTYPED flag may be clear, even if the function was
64 defined in prototype style. When calling a function whose
65 TYPE_FLAG_PROTOTYPED flag is clear, GDB consults this flag to
68 For modern targets, it is proper to assume that, if the prototype
69 flag is clear, that can be trusted: `float' arguments should be
70 promoted to `double'. For some older targets, if the prototype
71 flag is clear, that doesn't tell us anything. The default is to
72 trust the debug information; the user can override this behavior
73 with "set coerce-float-to-double 0". */
75 static int coerce_float_to_double_p = 1;
77 show_coerce_float_to_double_p (struct ui_file *file, int from_tty,
78 struct cmd_list_element *c, const char *value)
80 fprintf_filtered (file,
81 _("Coercion of floats to doubles "
82 "when calling functions is %s.\n"),
86 /* This boolean tells what gdb should do if a signal is received while
87 in a function called from gdb (call dummy). If set, gdb unwinds
88 the stack and restore the context to what as it was before the
91 The default is to stop in the frame where the signal was received. */
93 int unwind_on_signal_p = 0;
95 show_unwind_on_signal_p (struct ui_file *file, int from_tty,
96 struct cmd_list_element *c, const char *value)
98 fprintf_filtered (file,
99 _("Unwinding of stack if a signal is "
100 "received while in a call dummy is %s.\n"),
104 /* This boolean tells what gdb should do if a std::terminate call is
105 made while in a function called from gdb (call dummy).
106 As the confines of a single dummy stack prohibit out-of-frame
107 handlers from handling a raised exception, and as out-of-frame
108 handlers are common in C++, this can lead to no handler being found
109 by the unwinder, and a std::terminate call. This is a false positive.
110 If set, gdb unwinds the stack and restores the context to what it
113 The default is to unwind the frame if a std::terminate call is
116 static int unwind_on_terminating_exception_p = 1;
119 show_unwind_on_terminating_exception_p (struct ui_file *file, int from_tty,
120 struct cmd_list_element *c,
124 fprintf_filtered (file,
125 _("Unwind stack if a C++ exception is "
126 "unhandled while in a call dummy is %s.\n"),
130 /* Perform the standard coercions that are specified
131 for arguments to be passed to C or Ada functions.
133 If PARAM_TYPE is non-NULL, it is the expected parameter type.
134 IS_PROTOTYPED is non-zero if the function declaration is prototyped.
135 SP is the stack pointer were additional data can be pushed (updating
136 its value as needed). */
138 static struct value *
139 value_arg_coerce (struct gdbarch *gdbarch, struct value *arg,
140 struct type *param_type, int is_prototyped, CORE_ADDR *sp)
142 const struct builtin_type *builtin = builtin_type (gdbarch);
143 struct type *arg_type = check_typedef (value_type (arg));
145 = param_type ? check_typedef (param_type) : arg_type;
147 /* Perform any Ada-specific coercion first. */
148 if (current_language->la_language == language_ada)
149 arg = ada_convert_actual (arg, type);
151 /* Force the value to the target if we will need its address. At
152 this point, we could allocate arguments on the stack instead of
153 calling malloc if we knew that their addresses would not be
154 saved by the called function. */
155 arg = value_coerce_to_target (arg);
157 switch (TYPE_CODE (type))
161 struct value *new_value;
163 if (TYPE_CODE (arg_type) == TYPE_CODE_REF)
164 return value_cast_pointers (type, arg);
166 /* Cast the value to the reference's target type, and then
167 convert it back to a reference. This will issue an error
168 if the value was not previously in memory - in some cases
169 we should clearly be allowing this, but how? */
170 new_value = value_cast (TYPE_TARGET_TYPE (type), arg);
171 new_value = value_ref (new_value);
178 /* If we don't have a prototype, coerce to integer type if necessary. */
181 if (TYPE_LENGTH (type) < TYPE_LENGTH (builtin->builtin_int))
182 type = builtin->builtin_int;
184 /* Currently all target ABIs require at least the width of an integer
185 type for an argument. We may have to conditionalize the following
186 type coercion for future targets. */
187 if (TYPE_LENGTH (type) < TYPE_LENGTH (builtin->builtin_int))
188 type = builtin->builtin_int;
191 if (!is_prototyped && coerce_float_to_double_p)
193 if (TYPE_LENGTH (type) < TYPE_LENGTH (builtin->builtin_double))
194 type = builtin->builtin_double;
195 else if (TYPE_LENGTH (type) > TYPE_LENGTH (builtin->builtin_double))
196 type = builtin->builtin_long_double;
200 type = lookup_pointer_type (type);
202 case TYPE_CODE_ARRAY:
203 /* Arrays are coerced to pointers to their first element, unless
204 they are vectors, in which case we want to leave them alone,
205 because they are passed by value. */
206 if (current_language->c_style_arrays)
207 if (!TYPE_VECTOR (type))
208 type = lookup_pointer_type (TYPE_TARGET_TYPE (type));
210 case TYPE_CODE_UNDEF:
212 case TYPE_CODE_STRUCT:
213 case TYPE_CODE_UNION:
216 case TYPE_CODE_RANGE:
217 case TYPE_CODE_STRING:
218 case TYPE_CODE_BITSTRING:
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 minimal_symbol *msymbol = lookup_minimal_symbol_by_pc (funaddr);
364 return SYMBOL_PRINT_NAME (msymbol);
368 char *tmp = xstrprintf (_(RAW_FUNCTION_ADDRESS_FORMAT),
369 hex_string (funaddr));
371 gdb_assert (strlen (tmp) + 1 <= buf_size);
378 /* Subroutine of call_function_by_hand to simplify it.
379 Start up the inferior and wait for it to stop.
380 Return the exception if there's an error, or an exception with
381 reason >= 0 if there's no error.
383 This is done inside a TRY_CATCH so the caller needn't worry about
384 thrown errors. The caller should rethrow if there's an error. */
386 static struct gdb_exception
387 run_inferior_call (struct thread_info *call_thread, CORE_ADDR real_pc)
389 volatile struct gdb_exception e;
390 int saved_in_infcall = call_thread->control.in_infcall;
391 ptid_t call_thread_ptid = call_thread->ptid;
393 call_thread->control.in_infcall = 1;
395 clear_proceed_status ();
397 disable_watchpoints_before_interactive_call_start ();
399 /* We want stop_registers, please... */
400 call_thread->control.proceed_to_finish = 1;
402 TRY_CATCH (e, RETURN_MASK_ALL)
404 proceed (real_pc, TARGET_SIGNAL_0, 0);
406 /* Inferior function calls are always synchronous, even if the
407 target supports asynchronous execution. Do here what
408 `proceed' itself does in sync mode. */
409 if (target_can_async_p () && is_running (inferior_ptid))
411 wait_for_inferior ();
416 /* At this point the current thread may have changed. Refresh
417 CALL_THREAD as it could be invalid if its thread has exited. */
418 call_thread = find_thread_ptid (call_thread_ptid);
420 enable_watchpoints_after_interactive_call_stop ();
422 /* Call breakpoint_auto_delete on the current contents of the bpstat
423 of inferior call thread.
424 If all error()s out of proceed ended up calling normal_stop
425 (and perhaps they should; it already does in the special case
426 of error out of resume()), then we wouldn't need this. */
429 if (call_thread != NULL)
430 breakpoint_auto_delete (call_thread->control.stop_bpstat);
433 if (call_thread != NULL)
434 call_thread->control.in_infcall = saved_in_infcall;
439 /* A cleanup function that calls delete_std_terminate_breakpoint. */
441 cleanup_delete_std_terminate_breakpoint (void *ignore)
443 delete_std_terminate_breakpoint ();
446 /* All this stuff with a dummy frame may seem unnecessarily complicated
447 (why not just save registers in GDB?). The purpose of pushing a dummy
448 frame which looks just like a real frame is so that if you call a
449 function and then hit a breakpoint (get a signal, etc), "backtrace"
450 will look right. Whether the backtrace needs to actually show the
451 stack at the time the inferior function was called is debatable, but
452 it certainly needs to not display garbage. So if you are contemplating
453 making dummy frames be different from normal frames, consider that. */
455 /* Perform a function call in the inferior.
456 ARGS is a vector of values of arguments (NARGS of them).
457 FUNCTION is a value, the function to be called.
458 Returns a value representing what the function returned.
459 May fail to return, if a breakpoint or signal is hit
460 during the execution of the function.
462 ARGS is modified to contain coerced values. */
465 call_function_by_hand (struct value *function, int nargs, struct value **args)
468 struct type *values_type, *target_values_type;
469 unsigned char struct_return = 0, lang_struct_return = 0;
470 CORE_ADDR struct_addr = 0;
471 struct infcall_control_state *inf_status;
472 struct cleanup *inf_status_cleanup;
473 struct infcall_suspend_state *caller_state;
476 struct type *ftype = check_typedef (value_type (function));
478 struct frame_id dummy_id;
479 struct cleanup *args_cleanup;
480 struct frame_info *frame;
481 struct gdbarch *gdbarch;
482 struct cleanup *terminate_bp_cleanup;
483 ptid_t call_thread_ptid;
484 struct gdb_exception e;
485 char name_buf[RAW_FUNCTION_ADDRESS_SIZE];
487 if (TYPE_CODE (ftype) == TYPE_CODE_PTR)
488 ftype = check_typedef (TYPE_TARGET_TYPE (ftype));
490 if (!target_has_execution)
493 if (get_traceframe_number () >= 0)
494 error (_("May not call functions while looking at trace frames."));
496 if (execution_direction == EXEC_REVERSE)
497 error (_("Cannot call functions in reverse mode."));
499 frame = get_current_frame ();
500 gdbarch = get_frame_arch (frame);
502 if (!gdbarch_push_dummy_call_p (gdbarch))
503 error (_("This target does not support function calls."));
505 /* A cleanup for the inferior status.
506 This is only needed while we're preparing the inferior function call. */
507 inf_status = save_infcall_control_state ();
509 = make_cleanup_restore_infcall_control_state (inf_status);
511 /* Save the caller's registers and other state associated with the
512 inferior itself so that they can be restored once the
513 callee returns. To allow nested calls the registers are (further
514 down) pushed onto a dummy frame stack. Include a cleanup (which
515 is tossed once the regcache has been pushed). */
516 caller_state = save_infcall_suspend_state ();
517 make_cleanup_restore_infcall_suspend_state (caller_state);
519 /* Ensure that the initial SP is correctly aligned. */
521 CORE_ADDR old_sp = get_frame_sp (frame);
523 if (gdbarch_frame_align_p (gdbarch))
525 sp = gdbarch_frame_align (gdbarch, old_sp);
526 /* NOTE: cagney/2003-08-13: Skip the "red zone". For some
527 ABIs, a function can use memory beyond the inner most stack
528 address. AMD64 called that region the "red zone". Skip at
529 least the "red zone" size before allocating any space on
531 if (gdbarch_inner_than (gdbarch, 1, 2))
532 sp -= gdbarch_frame_red_zone_size (gdbarch);
534 sp += gdbarch_frame_red_zone_size (gdbarch);
536 gdb_assert (sp == gdbarch_frame_align (gdbarch, sp));
537 /* NOTE: cagney/2002-09-18:
539 On a RISC architecture, a void parameterless generic dummy
540 frame (i.e., no parameters, no result) typically does not
541 need to push anything the stack and hence can leave SP and
542 FP. Similarly, a frameless (possibly leaf) function does
543 not push anything on the stack and, hence, that too can
544 leave FP and SP unchanged. As a consequence, a sequence of
545 void parameterless generic dummy frame calls to frameless
546 functions will create a sequence of effectively identical
547 frames (SP, FP and TOS and PC the same). This, not
548 suprisingly, results in what appears to be a stack in an
549 infinite loop --- when GDB tries to find a generic dummy
550 frame on the internal dummy frame stack, it will always
553 To avoid this problem, the code below always grows the
554 stack. That way, two dummy frames can never be identical.
555 It does burn a few bytes of stack but that is a small price
559 if (gdbarch_inner_than (gdbarch, 1, 2))
560 /* Stack grows down. */
561 sp = gdbarch_frame_align (gdbarch, old_sp - 1);
563 /* Stack grows up. */
564 sp = gdbarch_frame_align (gdbarch, old_sp + 1);
566 /* SP may have underflown address zero here from OLD_SP. Memory access
567 functions will probably fail in such case but that is a target's
571 /* FIXME: cagney/2002-09-18: Hey, you loose!
573 Who knows how badly aligned the SP is!
575 If the generic dummy frame ends up empty (because nothing is
576 pushed) GDB won't be able to correctly perform back traces.
577 If a target is having trouble with backtraces, first thing to
578 do is add FRAME_ALIGN() to the architecture vector. If that
579 fails, try dummy_id().
581 If the ABI specifies a "Red Zone" (see the doco) the code
582 below will quietly trash it. */
586 funaddr = find_function_addr (function, &values_type);
588 values_type = builtin_type (gdbarch)->builtin_int;
590 CHECK_TYPEDEF (values_type);
592 /* Are we returning a value using a structure return (passing a
593 hidden argument pointing to storage) or a normal value return?
594 There are two cases: language-mandated structure return and
595 target ABI structure return. The variable STRUCT_RETURN only
596 describes the latter. The language version is handled by passing
597 the return location as the first parameter to the function,
598 even preceding "this". This is different from the target
599 ABI version, which is target-specific; for instance, on ia64
600 the first argument is passed in out0 but the hidden structure
601 return pointer would normally be passed in r8. */
603 if (language_pass_by_reference (values_type))
605 lang_struct_return = 1;
607 /* Tell the target specific argument pushing routine not to
609 target_values_type = builtin_type (gdbarch)->builtin_void;
613 struct_return = using_struct_return (gdbarch,
614 value_type (function), values_type);
615 target_values_type = values_type;
618 /* Determine the location of the breakpoint (and possibly other
619 stuff) that the called function will return to. The SPARC, for a
620 function returning a structure or union, needs to make space for
621 not just the breakpoint but also an extra word containing the
622 size (?) of the structure being passed. */
624 /* The actual breakpoint (at BP_ADDR) is inserted separatly so there
625 is no need to write that out. */
627 switch (gdbarch_call_dummy_location (gdbarch))
630 sp = push_dummy_code (gdbarch, sp, funaddr,
631 args, nargs, target_values_type,
632 &real_pc, &bp_addr, get_current_regcache ());
635 /* Some executables define a symbol __CALL_DUMMY_ADDRESS whose
636 address is the location where the breakpoint should be
637 placed. Once all targets are using the overhauled frame code
638 this can be deleted - ON_STACK is a better option. */
640 struct minimal_symbol *sym;
641 CORE_ADDR dummy_addr;
643 sym = lookup_minimal_symbol ("__CALL_DUMMY_ADDRESS", NULL, NULL);
647 dummy_addr = SYMBOL_VALUE_ADDRESS (sym);
648 /* Make certain that the address points at real code, and not
649 a function descriptor. */
650 dummy_addr = gdbarch_convert_from_func_ptr_addr (gdbarch,
653 /* A call dummy always consists of just a single breakpoint,
654 so its address is the same as the address of the dummy. */
655 bp_addr = dummy_addr;
662 CORE_ADDR dummy_addr;
666 dummy_addr = entry_point_address ();
668 /* If the inferior call throws an uncaught C++ exception,
669 the inferior unwinder tries to unwind all frames, including
670 our dummy frame. The unwinder determines the address of
671 the calling instruction by subtracting 1 to the return
672 address. So, using the entry point's address as the return
673 address would lead the unwinder to use the unwinding
674 information of the code immediately preceding the entry
675 point. This information, if found, is invalid for the dummy
676 frame, and can potentially crash the inferior's unwinder.
677 Therefore, we adjust the return address by the length of
678 a breakpoint, guaranteeing that the unwinder finds the
679 correct function as the caller. */
681 gdbarch_breakpoint_from_pc (gdbarch, &dummy_addr, &bp_len);
682 dummy_addr += bp_len;
684 /* A call dummy always consists of just a single breakpoint, so
685 its address is the same as the address of the dummy. */
686 bp_addr = dummy_addr;
690 internal_error (__FILE__, __LINE__, _("bad switch"));
693 if (nargs < TYPE_NFIELDS (ftype))
694 error (_("Too few arguments in function call."));
699 for (i = nargs - 1; i >= 0; i--)
702 struct type *param_type;
704 /* FIXME drow/2002-05-31: Should just always mark methods as
705 prototyped. Can we respect TYPE_VARARGS? Probably not. */
706 if (TYPE_CODE (ftype) == TYPE_CODE_METHOD)
708 else if (i < TYPE_NFIELDS (ftype))
709 prototyped = TYPE_PROTOTYPED (ftype);
713 if (i < TYPE_NFIELDS (ftype))
714 param_type = TYPE_FIELD_TYPE (ftype, i);
718 args[i] = value_arg_coerce (gdbarch, args[i],
719 param_type, prototyped, &sp);
721 if (param_type != NULL && language_pass_by_reference (param_type))
722 args[i] = value_addr (args[i]);
726 /* Reserve space for the return structure to be written on the
727 stack, if necessary. Make certain that the value is correctly
730 if (struct_return || lang_struct_return)
732 int len = TYPE_LENGTH (values_type);
734 if (gdbarch_inner_than (gdbarch, 1, 2))
736 /* Stack grows downward. Align STRUCT_ADDR and SP after
737 making space for the return value. */
739 if (gdbarch_frame_align_p (gdbarch))
740 sp = gdbarch_frame_align (gdbarch, sp);
745 /* Stack grows upward. Align the frame, allocate space, and
746 then again, re-align the frame??? */
747 if (gdbarch_frame_align_p (gdbarch))
748 sp = gdbarch_frame_align (gdbarch, sp);
751 if (gdbarch_frame_align_p (gdbarch))
752 sp = gdbarch_frame_align (gdbarch, sp);
756 if (lang_struct_return)
758 struct value **new_args;
760 /* Add the new argument to the front of the argument list. */
761 new_args = xmalloc (sizeof (struct value *) * (nargs + 1));
762 new_args[0] = value_from_pointer (lookup_pointer_type (values_type),
764 memcpy (&new_args[1], &args[0], sizeof (struct value *) * nargs);
767 args_cleanup = make_cleanup (xfree, args);
770 args_cleanup = make_cleanup (null_cleanup, NULL);
772 /* Create the dummy stack frame. Pass in the call dummy address as,
773 presumably, the ABI code knows where, in the call dummy, the
774 return address should be pointed. */
775 sp = gdbarch_push_dummy_call (gdbarch, function, get_current_regcache (),
776 bp_addr, nargs, args,
777 sp, struct_return, struct_addr);
779 do_cleanups (args_cleanup);
781 /* Set up a frame ID for the dummy frame so we can pass it to
782 set_momentary_breakpoint. We need to give the breakpoint a frame
783 ID so that the breakpoint code can correctly re-identify the
785 /* Sanity. The exact same SP value is returned by PUSH_DUMMY_CALL,
786 saved as the dummy-frame TOS, and used by dummy_id to form
787 the frame ID's stack address. */
788 dummy_id = frame_id_build (sp, bp_addr);
790 /* Create a momentary breakpoint at the return address of the
791 inferior. That way it breaks when it returns. */
794 struct breakpoint *bpt;
795 struct symtab_and_line sal;
797 init_sal (&sal); /* initialize to zeroes */
798 sal.pspace = current_program_space;
800 sal.section = find_pc_overlay (sal.pc);
801 /* Sanity. The exact same SP value is returned by
802 PUSH_DUMMY_CALL, saved as the dummy-frame TOS, and used by
803 dummy_id to form the frame ID's stack address. */
804 bpt = set_momentary_breakpoint (gdbarch, sal, dummy_id, bp_call_dummy);
805 bpt->disposition = disp_del;
808 /* Create a breakpoint in std::terminate.
809 If a C++ exception is raised in the dummy-frame, and the
810 exception handler is (normally, and expected to be) out-of-frame,
811 the default C++ handler will (wrongly) be called in an inferior
812 function call. This is wrong, as an exception can be normally
813 and legally handled out-of-frame. The confines of the dummy frame
814 prevent the unwinder from finding the correct handler (or any
815 handler, unless it is in-frame). The default handler calls
816 std::terminate. This will kill the inferior. Assert that
817 terminate should never be called in an inferior function
818 call. Place a momentary breakpoint in the std::terminate function
819 and if triggered in the call, rewind. */
820 if (unwind_on_terminating_exception_p)
821 set_std_terminate_breakpoint ();
823 /* Everything's ready, push all the info needed to restore the
824 caller (and identify the dummy-frame) onto the dummy-frame
826 dummy_frame_push (caller_state, &dummy_id);
828 /* Discard both inf_status and caller_state cleanups.
829 From this point on we explicitly restore the associated state
831 discard_cleanups (inf_status_cleanup);
833 /* Register a clean-up for unwind_on_terminating_exception_breakpoint. */
834 terminate_bp_cleanup = make_cleanup (cleanup_delete_std_terminate_breakpoint,
837 /* - SNIP - SNIP - SNIP - SNIP - SNIP - SNIP - SNIP - SNIP - SNIP -
838 If you're looking to implement asynchronous dummy-frames, then
839 just below is the place to chop this function in two.. */
841 /* TP is invalid after run_inferior_call returns, so enclose this
842 in a block so that it's only in scope during the time it's valid. */
844 struct thread_info *tp = inferior_thread ();
846 /* Save this thread's ptid, we need it later but the thread
848 call_thread_ptid = tp->ptid;
850 /* Run the inferior until it stops. */
852 e = run_inferior_call (tp, real_pc);
855 /* Rethrow an error if we got one trying to run the inferior. */
859 const char *name = get_function_name (funaddr,
860 name_buf, sizeof (name_buf));
862 discard_infcall_control_state (inf_status);
864 /* We could discard the dummy frame here if the program exited,
865 but it will get garbage collected the next time the program is
871 throw_error (e.error, _("%s\n\
872 An error occurred while in a function called from GDB.\n\
873 Evaluation of the expression containing the function\n\
874 (%s) will be abandoned.\n\
875 When the function is done executing, GDB will silently stop."),
883 /* If the program has exited, or we stopped at a different thread,
884 exit and inform the user. */
886 if (! target_has_execution)
888 const char *name = get_function_name (funaddr,
889 name_buf, sizeof (name_buf));
891 /* If we try to restore the inferior status,
892 we'll crash as the inferior is no longer running. */
893 discard_infcall_control_state (inf_status);
895 /* We could discard the dummy frame here given that the program exited,
896 but it will get garbage collected the next time the program is
899 error (_("The program being debugged exited while in a function "
901 "Evaluation of the expression containing the function\n"
902 "(%s) will be abandoned."),
906 if (! ptid_equal (call_thread_ptid, inferior_ptid))
908 const char *name = get_function_name (funaddr,
909 name_buf, sizeof (name_buf));
911 /* We've switched threads. This can happen if another thread gets a
912 signal or breakpoint while our thread was running.
913 There's no point in restoring the inferior status,
914 we're in a different thread. */
915 discard_infcall_control_state (inf_status);
916 /* Keep the dummy frame record, if the user switches back to the
917 thread with the hand-call, we'll need it. */
918 if (stopped_by_random_signal)
920 The program received a signal in another thread while\n\
921 making a function call from GDB.\n\
922 Evaluation of the expression containing the function\n\
923 (%s) will be abandoned.\n\
924 When the function is done executing, GDB will silently stop."),
928 The program stopped in another thread while making a function call from GDB.\n\
929 Evaluation of the expression containing the function\n\
930 (%s) will be abandoned.\n\
931 When the function is done executing, GDB will silently stop."),
935 if (stopped_by_random_signal || stop_stack_dummy != STOP_STACK_DUMMY)
937 const char *name = get_function_name (funaddr,
938 name_buf, sizeof (name_buf));
940 if (stopped_by_random_signal)
942 /* We stopped inside the FUNCTION because of a random
943 signal. Further execution of the FUNCTION is not
946 if (unwind_on_signal_p)
948 /* The user wants the context restored. */
950 /* We must get back to the frame we were before the
952 dummy_frame_pop (dummy_id);
954 /* We also need to restore inferior status to that before the
956 restore_infcall_control_state (inf_status);
958 /* FIXME: Insert a bunch of wrap_here; name can be very
959 long if it's a C++ name with arguments and stuff. */
961 The program being debugged was signaled while in a function called from GDB.\n\
962 GDB has restored the context to what it was before the call.\n\
963 To change this behavior use \"set unwindonsignal off\".\n\
964 Evaluation of the expression containing the function\n\
965 (%s) will be abandoned."),
970 /* The user wants to stay in the frame where we stopped
972 Discard inferior status, we're not at the same point
974 discard_infcall_control_state (inf_status);
976 /* FIXME: Insert a bunch of wrap_here; name can be very
977 long if it's a C++ name with arguments and stuff. */
979 The program being debugged was signaled while in a function called from GDB.\n\
980 GDB remains in the frame where the signal was received.\n\
981 To change this behavior use \"set unwindonsignal on\".\n\
982 Evaluation of the expression containing the function\n\
983 (%s) will be abandoned.\n\
984 When the function is done executing, GDB will silently stop."),
989 if (stop_stack_dummy == STOP_STD_TERMINATE)
991 /* We must get back to the frame we were before the dummy
993 dummy_frame_pop (dummy_id);
995 /* We also need to restore inferior status to that before
997 restore_infcall_control_state (inf_status);
1000 The program being debugged entered a std::terminate call, most likely\n\
1001 caused by an unhandled C++ exception. GDB blocked this call in order\n\
1002 to prevent the program from being terminated, and has restored the\n\
1003 context to its original state before the call.\n\
1004 To change this behaviour use \"set unwind-on-terminating-exception off\".\n\
1005 Evaluation of the expression containing the function (%s)\n\
1006 will be abandoned."),
1009 else if (stop_stack_dummy == STOP_NONE)
1012 /* We hit a breakpoint inside the FUNCTION.
1013 Keep the dummy frame, the user may want to examine its state.
1014 Discard inferior status, we're not at the same point
1016 discard_infcall_control_state (inf_status);
1018 /* The following error message used to say "The expression
1019 which contained the function call has been discarded."
1020 It is a hard concept to explain in a few words. Ideally,
1021 GDB would be able to resume evaluation of the expression
1022 when the function finally is done executing. Perhaps
1023 someday this will be implemented (it would not be easy). */
1024 /* FIXME: Insert a bunch of wrap_here; name can be very long if it's
1025 a C++ name with arguments and stuff. */
1027 The program being debugged stopped while in a function called from GDB.\n\
1028 Evaluation of the expression containing the function\n\
1029 (%s) will be abandoned.\n\
1030 When the function is done executing, GDB will silently stop."),
1034 /* The above code errors out, so ... */
1035 internal_error (__FILE__, __LINE__, _("... should not be here"));
1038 do_cleanups (terminate_bp_cleanup);
1040 /* If we get here the called FUNCTION ran to completion,
1041 and the dummy frame has already been popped. */
1044 struct address_space *aspace = get_regcache_aspace (stop_registers);
1045 struct regcache *retbuf = regcache_xmalloc (gdbarch, aspace);
1046 struct cleanup *retbuf_cleanup = make_cleanup_regcache_xfree (retbuf);
1047 struct value *retval = NULL;
1049 regcache_cpy_no_passthrough (retbuf, stop_registers);
1051 /* Inferior call is successful. Restore the inferior status.
1052 At this stage, leave the RETBUF alone. */
1053 restore_infcall_control_state (inf_status);
1055 /* Figure out the value returned by the function. */
1056 retval = allocate_value (values_type);
1058 if (lang_struct_return)
1059 read_value_memory (retval, 0, 1, struct_addr,
1060 value_contents_raw (retval),
1061 TYPE_LENGTH (values_type));
1062 else if (TYPE_CODE (target_values_type) != TYPE_CODE_VOID)
1064 /* If the function returns void, don't bother fetching the
1066 switch (gdbarch_return_value (gdbarch, value_type (function),
1067 target_values_type, NULL, NULL, NULL))
1069 case RETURN_VALUE_REGISTER_CONVENTION:
1070 case RETURN_VALUE_ABI_RETURNS_ADDRESS:
1071 case RETURN_VALUE_ABI_PRESERVES_ADDRESS:
1072 gdbarch_return_value (gdbarch, value_type (function), values_type,
1073 retbuf, value_contents_raw (retval), NULL);
1075 case RETURN_VALUE_STRUCT_CONVENTION:
1076 read_value_memory (retval, 0, 1, struct_addr,
1077 value_contents_raw (retval),
1078 TYPE_LENGTH (values_type));
1083 do_cleanups (retbuf_cleanup);
1085 gdb_assert (retval);
1091 /* Provide a prototype to silence -Wmissing-prototypes. */
1092 void _initialize_infcall (void);
1095 _initialize_infcall (void)
1097 add_setshow_boolean_cmd ("coerce-float-to-double", class_obscure,
1098 &coerce_float_to_double_p, _("\
1099 Set coercion of floats to doubles when calling functions."), _("\
1100 Show coercion of floats to doubles when calling functions"), _("\
1101 Variables of type float should generally be converted to doubles before\n\
1102 calling an unprototyped function, and left alone when calling a prototyped\n\
1103 function. However, some older debug info formats do not provide enough\n\
1104 information to determine that a function is prototyped. If this flag is\n\
1105 set, GDB will perform the conversion for a function it considers\n\
1107 The default is to perform the conversion.\n"),
1109 show_coerce_float_to_double_p,
1110 &setlist, &showlist);
1112 add_setshow_boolean_cmd ("unwindonsignal", no_class,
1113 &unwind_on_signal_p, _("\
1114 Set unwinding of stack if a signal is received while in a call dummy."), _("\
1115 Show unwinding of stack if a signal is received while in a call dummy."), _("\
1116 The unwindonsignal lets the user determine what gdb should do if a signal\n\
1117 is received while in a function called from gdb (call dummy). If set, gdb\n\
1118 unwinds the stack and restore the context to what as it was before the call.\n\
1119 The default is to stop in the frame where the signal was received."),
1121 show_unwind_on_signal_p,
1122 &setlist, &showlist);
1124 add_setshow_boolean_cmd ("unwind-on-terminating-exception", no_class,
1125 &unwind_on_terminating_exception_p, _("\
1126 Set unwinding of stack if std::terminate is called while in call dummy."), _("\
1127 Show unwinding of stack if std::terminate() is called while in a call dummy."),
1129 The unwind on terminating exception flag lets the user determine\n\
1130 what gdb should do if a std::terminate() call is made from the\n\
1131 default exception handler. If set, gdb unwinds the stack and restores\n\
1132 the context to what it was before the call. If unset, gdb allows the\n\
1133 std::terminate call to proceed.\n\
1134 The default is to unwind the frame."),
1136 show_unwind_on_terminating_exception_p,
1137 &setlist, &showlist);