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 ());
636 CORE_ADDR dummy_addr;
639 dummy_addr = entry_point_address ();
640 /* A call dummy always consists of just a single breakpoint, so
641 its address is the same as the address of the dummy. */
642 bp_addr = dummy_addr;
646 /* Some executables define a symbol __CALL_DUMMY_ADDRESS whose
647 address is the location where the breakpoint should be
648 placed. Once all targets are using the overhauled frame code
649 this can be deleted - ON_STACK is a better option. */
651 struct minimal_symbol *sym;
652 CORE_ADDR dummy_addr;
654 sym = lookup_minimal_symbol ("__CALL_DUMMY_ADDRESS", NULL, NULL);
658 dummy_addr = SYMBOL_VALUE_ADDRESS (sym);
659 /* Make certain that the address points at real code, and not
660 a function descriptor. */
661 dummy_addr = gdbarch_convert_from_func_ptr_addr (gdbarch,
666 dummy_addr = entry_point_address ();
667 /* A call dummy always consists of just a single breakpoint,
668 so it's address is the same as the address of the dummy. */
669 bp_addr = dummy_addr;
673 internal_error (__FILE__, __LINE__, _("bad switch"));
676 if (nargs < TYPE_NFIELDS (ftype))
677 error (_("Too few arguments in function call."));
682 for (i = nargs - 1; i >= 0; i--)
685 struct type *param_type;
687 /* FIXME drow/2002-05-31: Should just always mark methods as
688 prototyped. Can we respect TYPE_VARARGS? Probably not. */
689 if (TYPE_CODE (ftype) == TYPE_CODE_METHOD)
691 else if (i < TYPE_NFIELDS (ftype))
692 prototyped = TYPE_PROTOTYPED (ftype);
696 if (i < TYPE_NFIELDS (ftype))
697 param_type = TYPE_FIELD_TYPE (ftype, i);
701 args[i] = value_arg_coerce (gdbarch, args[i],
702 param_type, prototyped, &sp);
704 if (param_type != NULL && language_pass_by_reference (param_type))
705 args[i] = value_addr (args[i]);
709 /* Reserve space for the return structure to be written on the
710 stack, if necessary. Make certain that the value is correctly
713 if (struct_return || lang_struct_return)
715 int len = TYPE_LENGTH (values_type);
717 if (gdbarch_inner_than (gdbarch, 1, 2))
719 /* Stack grows downward. Align STRUCT_ADDR and SP after
720 making space for the return value. */
722 if (gdbarch_frame_align_p (gdbarch))
723 sp = gdbarch_frame_align (gdbarch, sp);
728 /* Stack grows upward. Align the frame, allocate space, and
729 then again, re-align the frame??? */
730 if (gdbarch_frame_align_p (gdbarch))
731 sp = gdbarch_frame_align (gdbarch, sp);
734 if (gdbarch_frame_align_p (gdbarch))
735 sp = gdbarch_frame_align (gdbarch, sp);
739 if (lang_struct_return)
741 struct value **new_args;
743 /* Add the new argument to the front of the argument list. */
744 new_args = xmalloc (sizeof (struct value *) * (nargs + 1));
745 new_args[0] = value_from_pointer (lookup_pointer_type (values_type),
747 memcpy (&new_args[1], &args[0], sizeof (struct value *) * nargs);
750 args_cleanup = make_cleanup (xfree, args);
753 args_cleanup = make_cleanup (null_cleanup, NULL);
755 /* Create the dummy stack frame. Pass in the call dummy address as,
756 presumably, the ABI code knows where, in the call dummy, the
757 return address should be pointed. */
758 sp = gdbarch_push_dummy_call (gdbarch, function, get_current_regcache (),
759 bp_addr, nargs, args,
760 sp, struct_return, struct_addr);
762 do_cleanups (args_cleanup);
764 /* Set up a frame ID for the dummy frame so we can pass it to
765 set_momentary_breakpoint. We need to give the breakpoint a frame
766 ID so that the breakpoint code can correctly re-identify the
768 /* Sanity. The exact same SP value is returned by PUSH_DUMMY_CALL,
769 saved as the dummy-frame TOS, and used by dummy_id to form
770 the frame ID's stack address. */
771 dummy_id = frame_id_build (sp, bp_addr);
773 /* Create a momentary breakpoint at the return address of the
774 inferior. That way it breaks when it returns. */
777 struct breakpoint *bpt;
778 struct symtab_and_line sal;
780 init_sal (&sal); /* initialize to zeroes */
781 sal.pspace = current_program_space;
783 sal.section = find_pc_overlay (sal.pc);
784 /* Sanity. The exact same SP value is returned by
785 PUSH_DUMMY_CALL, saved as the dummy-frame TOS, and used by
786 dummy_id to form the frame ID's stack address. */
787 bpt = set_momentary_breakpoint (gdbarch, sal, dummy_id, bp_call_dummy);
788 bpt->disposition = disp_del;
791 /* Create a breakpoint in std::terminate.
792 If a C++ exception is raised in the dummy-frame, and the
793 exception handler is (normally, and expected to be) out-of-frame,
794 the default C++ handler will (wrongly) be called in an inferior
795 function call. This is wrong, as an exception can be normally
796 and legally handled out-of-frame. The confines of the dummy frame
797 prevent the unwinder from finding the correct handler (or any
798 handler, unless it is in-frame). The default handler calls
799 std::terminate. This will kill the inferior. Assert that
800 terminate should never be called in an inferior function
801 call. Place a momentary breakpoint in the std::terminate function
802 and if triggered in the call, rewind. */
803 if (unwind_on_terminating_exception_p)
804 set_std_terminate_breakpoint ();
806 /* Everything's ready, push all the info needed to restore the
807 caller (and identify the dummy-frame) onto the dummy-frame
809 dummy_frame_push (caller_state, &dummy_id);
811 /* Discard both inf_status and caller_state cleanups.
812 From this point on we explicitly restore the associated state
814 discard_cleanups (inf_status_cleanup);
816 /* Register a clean-up for unwind_on_terminating_exception_breakpoint. */
817 terminate_bp_cleanup = make_cleanup (cleanup_delete_std_terminate_breakpoint,
820 /* - SNIP - SNIP - SNIP - SNIP - SNIP - SNIP - SNIP - SNIP - SNIP -
821 If you're looking to implement asynchronous dummy-frames, then
822 just below is the place to chop this function in two.. */
824 /* TP is invalid after run_inferior_call returns, so enclose this
825 in a block so that it's only in scope during the time it's valid. */
827 struct thread_info *tp = inferior_thread ();
829 /* Save this thread's ptid, we need it later but the thread
831 call_thread_ptid = tp->ptid;
833 /* Run the inferior until it stops. */
835 e = run_inferior_call (tp, real_pc);
838 /* Rethrow an error if we got one trying to run the inferior. */
842 const char *name = get_function_name (funaddr,
843 name_buf, sizeof (name_buf));
845 discard_infcall_control_state (inf_status);
847 /* We could discard the dummy frame here if the program exited,
848 but it will get garbage collected the next time the program is
854 throw_error (e.error, _("%s\n\
855 An error occurred while in a function called from GDB.\n\
856 Evaluation of the expression containing the function\n\
857 (%s) will be abandoned.\n\
858 When the function is done executing, GDB will silently stop."),
866 /* If the program has exited, or we stopped at a different thread,
867 exit and inform the user. */
869 if (! target_has_execution)
871 const char *name = get_function_name (funaddr,
872 name_buf, sizeof (name_buf));
874 /* If we try to restore the inferior status,
875 we'll crash as the inferior is no longer running. */
876 discard_infcall_control_state (inf_status);
878 /* We could discard the dummy frame here given that the program exited,
879 but it will get garbage collected the next time the program is
882 error (_("The program being debugged exited while in a function "
884 "Evaluation of the expression containing the function\n"
885 "(%s) will be abandoned."),
889 if (! ptid_equal (call_thread_ptid, inferior_ptid))
891 const char *name = get_function_name (funaddr,
892 name_buf, sizeof (name_buf));
894 /* We've switched threads. This can happen if another thread gets a
895 signal or breakpoint while our thread was running.
896 There's no point in restoring the inferior status,
897 we're in a different thread. */
898 discard_infcall_control_state (inf_status);
899 /* Keep the dummy frame record, if the user switches back to the
900 thread with the hand-call, we'll need it. */
901 if (stopped_by_random_signal)
903 The program received a signal in another thread while\n\
904 making a function call from GDB.\n\
905 Evaluation of the expression containing the function\n\
906 (%s) will be abandoned.\n\
907 When the function is done executing, GDB will silently stop."),
911 The program stopped in another thread while making a function call from GDB.\n\
912 Evaluation of the expression containing the function\n\
913 (%s) will be abandoned.\n\
914 When the function is done executing, GDB will silently stop."),
918 if (stopped_by_random_signal || stop_stack_dummy != STOP_STACK_DUMMY)
920 const char *name = get_function_name (funaddr,
921 name_buf, sizeof (name_buf));
923 if (stopped_by_random_signal)
925 /* We stopped inside the FUNCTION because of a random
926 signal. Further execution of the FUNCTION is not
929 if (unwind_on_signal_p)
931 /* The user wants the context restored. */
933 /* We must get back to the frame we were before the
935 dummy_frame_pop (dummy_id);
937 /* We also need to restore inferior status to that before the
939 restore_infcall_control_state (inf_status);
941 /* FIXME: Insert a bunch of wrap_here; name can be very
942 long if it's a C++ name with arguments and stuff. */
944 The program being debugged was signaled while in a function called from GDB.\n\
945 GDB has restored the context to what it was before the call.\n\
946 To change this behavior use \"set unwindonsignal off\".\n\
947 Evaluation of the expression containing the function\n\
948 (%s) will be abandoned."),
953 /* The user wants to stay in the frame where we stopped
955 Discard inferior status, we're not at the same point
957 discard_infcall_control_state (inf_status);
959 /* FIXME: Insert a bunch of wrap_here; name can be very
960 long if it's a C++ name with arguments and stuff. */
962 The program being debugged was signaled while in a function called from GDB.\n\
963 GDB remains in the frame where the signal was received.\n\
964 To change this behavior use \"set unwindonsignal on\".\n\
965 Evaluation of the expression containing the function\n\
966 (%s) will be abandoned.\n\
967 When the function is done executing, GDB will silently stop."),
972 if (stop_stack_dummy == STOP_STD_TERMINATE)
974 /* We must get back to the frame we were before the dummy
976 dummy_frame_pop (dummy_id);
978 /* We also need to restore inferior status to that before
980 restore_infcall_control_state (inf_status);
983 The program being debugged entered a std::terminate call, most likely\n\
984 caused by an unhandled C++ exception. GDB blocked this call in order\n\
985 to prevent the program from being terminated, and has restored the\n\
986 context to its original state before the call.\n\
987 To change this behaviour use \"set unwind-on-terminating-exception off\".\n\
988 Evaluation of the expression containing the function (%s)\n\
989 will be abandoned."),
992 else if (stop_stack_dummy == STOP_NONE)
995 /* We hit a breakpoint inside the FUNCTION.
996 Keep the dummy frame, the user may want to examine its state.
997 Discard inferior status, we're not at the same point
999 discard_infcall_control_state (inf_status);
1001 /* The following error message used to say "The expression
1002 which contained the function call has been discarded."
1003 It is a hard concept to explain in a few words. Ideally,
1004 GDB would be able to resume evaluation of the expression
1005 when the function finally is done executing. Perhaps
1006 someday this will be implemented (it would not be easy). */
1007 /* FIXME: Insert a bunch of wrap_here; name can be very long if it's
1008 a C++ name with arguments and stuff. */
1010 The program being debugged stopped while in a function called from GDB.\n\
1011 Evaluation of the expression containing the function\n\
1012 (%s) will be abandoned.\n\
1013 When the function is done executing, GDB will silently stop."),
1017 /* The above code errors out, so ... */
1018 internal_error (__FILE__, __LINE__, _("... should not be here"));
1021 do_cleanups (terminate_bp_cleanup);
1023 /* If we get here the called FUNCTION ran to completion,
1024 and the dummy frame has already been popped. */
1027 struct address_space *aspace = get_regcache_aspace (stop_registers);
1028 struct regcache *retbuf = regcache_xmalloc (gdbarch, aspace);
1029 struct cleanup *retbuf_cleanup = make_cleanup_regcache_xfree (retbuf);
1030 struct value *retval = NULL;
1032 regcache_cpy_no_passthrough (retbuf, stop_registers);
1034 /* Inferior call is successful. Restore the inferior status.
1035 At this stage, leave the RETBUF alone. */
1036 restore_infcall_control_state (inf_status);
1038 /* Figure out the value returned by the function. */
1039 retval = allocate_value (values_type);
1041 if (lang_struct_return)
1042 read_value_memory (retval, 0, 1, struct_addr,
1043 value_contents_raw (retval),
1044 TYPE_LENGTH (values_type));
1045 else if (TYPE_CODE (target_values_type) != TYPE_CODE_VOID)
1047 /* If the function returns void, don't bother fetching the
1049 switch (gdbarch_return_value (gdbarch, value_type (function),
1050 target_values_type, NULL, NULL, NULL))
1052 case RETURN_VALUE_REGISTER_CONVENTION:
1053 case RETURN_VALUE_ABI_RETURNS_ADDRESS:
1054 case RETURN_VALUE_ABI_PRESERVES_ADDRESS:
1055 gdbarch_return_value (gdbarch, value_type (function), values_type,
1056 retbuf, value_contents_raw (retval), NULL);
1058 case RETURN_VALUE_STRUCT_CONVENTION:
1059 read_value_memory (retval, 0, 1, struct_addr,
1060 value_contents_raw (retval),
1061 TYPE_LENGTH (values_type));
1066 do_cleanups (retbuf_cleanup);
1068 gdb_assert (retval);
1074 /* Provide a prototype to silence -Wmissing-prototypes. */
1075 void _initialize_infcall (void);
1078 _initialize_infcall (void)
1080 add_setshow_boolean_cmd ("coerce-float-to-double", class_obscure,
1081 &coerce_float_to_double_p, _("\
1082 Set coercion of floats to doubles when calling functions."), _("\
1083 Show coercion of floats to doubles when calling functions"), _("\
1084 Variables of type float should generally be converted to doubles before\n\
1085 calling an unprototyped function, and left alone when calling a prototyped\n\
1086 function. However, some older debug info formats do not provide enough\n\
1087 information to determine that a function is prototyped. If this flag is\n\
1088 set, GDB will perform the conversion for a function it considers\n\
1090 The default is to perform the conversion.\n"),
1092 show_coerce_float_to_double_p,
1093 &setlist, &showlist);
1095 add_setshow_boolean_cmd ("unwindonsignal", no_class,
1096 &unwind_on_signal_p, _("\
1097 Set unwinding of stack if a signal is received while in a call dummy."), _("\
1098 Show unwinding of stack if a signal is received while in a call dummy."), _("\
1099 The unwindonsignal lets the user determine what gdb should do if a signal\n\
1100 is received while in a function called from gdb (call dummy). If set, gdb\n\
1101 unwinds the stack and restore the context to what as it was before the call.\n\
1102 The default is to stop in the frame where the signal was received."),
1104 show_unwind_on_signal_p,
1105 &setlist, &showlist);
1107 add_setshow_boolean_cmd ("unwind-on-terminating-exception", no_class,
1108 &unwind_on_terminating_exception_p, _("\
1109 Set unwinding of stack if std::terminate is called while in call dummy."), _("\
1110 Show unwinding of stack if std::terminate() is called while in a call dummy."),
1112 The unwind on terminating exception flag lets the user determine\n\
1113 what gdb should do if a std::terminate() call is made from the\n\
1114 default exception handler. If set, gdb unwinds the stack and restores\n\
1115 the context to what it was before the call. If unset, gdb allows the\n\
1116 std::terminate call to proceed.\n\
1117 The default is to unwind the frame."),
1119 show_unwind_on_terminating_exception_p,
1120 &setlist, &showlist);