gdb/infcall.c

   1 /* Perform an inferior function call, for GDB, the GNU debugger.
   2
   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    Free Software Foundation, Inc.
   6
   7    This file is part of GDB.
   8
   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.
  13
  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.
  18
  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., 51 Franklin Street, Fifth Floor,
  22    Boston, MA 02110-1301, USA.  */
  23
  24 #include "defs.h"
  25 #include "breakpoint.h"
  26 #include "target.h"
  27 #include "regcache.h"
  28 #include "inferior.h"
  29 #include "gdb_assert.h"
  30 #include "block.h"
  31 #include "gdbcore.h"
  32 #include "language.h"
  33 #include "objfiles.h"
  34 #include "gdbcmd.h"
  35 #include "command.h"
  36 #include "gdb_string.h"
  37 #include "infcall.h"
  38 #include "dummy-frame.h"
  39
  40 /* NOTE: cagney/2003-04-16: What's the future of this code?
  41
  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.  */
  45
  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.
  52
  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
  58    decide what to do.
  59
  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".  */
  66
  67 static int coerce_float_to_double_p = 1;
  68 static void
  69 show_coerce_float_to_double_p (struct ui_file *file, int from_tty,
  70                                struct cmd_list_element *c, const char *value)
  71 {
  72   fprintf_filtered (file, _("\
  73 Coercion of floats to doubles when calling functions is %s.\n"),
  74                     value);
  75 }
  76
  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
  80    call.
  81
  82    The default is to stop in the frame where the signal was received. */
  83
  84 int unwind_on_signal_p = 0;
  85 static void
  86 show_unwind_on_signal_p (struct ui_file *file, int from_tty,
  87                          struct cmd_list_element *c, const char *value)
  88 {
  89   fprintf_filtered (file, _("\
  90 Unwinding of stack if a signal is received while in a call dummy is %s.\n"),
  91                     value);
  92 }
  93
  94
  95 /* Perform the standard coercions that are specified
  96    for arguments to be passed to C functions.
  97
  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.  */
 100
 101 static struct value *
 102 value_arg_coerce (struct value *arg, struct type *param_type,
 103                   int is_prototyped)
 104 {
 105   struct type *arg_type = check_typedef (value_type (arg));
 106   struct type *type
 107     = param_type ? check_typedef (param_type) : arg_type;
 108
 109   switch (TYPE_CODE (type))
 110     {
 111     case TYPE_CODE_REF:
 112       {
 113         struct value *new_value;
 114
 115         if (TYPE_CODE (arg_type) == TYPE_CODE_REF)
 116           return value_cast_pointers (type, arg);
 117
 118         /* Cast the value to the reference's target type, and then
 119            convert it back to a reference.  This will issue an error
 120            if the value was not previously in memory - in some cases
 121            we should clearly be allowing this, but how?  */
 122         new_value = value_cast (TYPE_TARGET_TYPE (type), arg);
 123         new_value = value_ref (new_value);
 124         return new_value;
 125       }
 126     case TYPE_CODE_INT:
 127     case TYPE_CODE_CHAR:
 128     case TYPE_CODE_BOOL:
 129     case TYPE_CODE_ENUM:
 130       /* If we don't have a prototype, coerce to integer type if necessary.  */
 131       if (!is_prototyped)
 132         {
 133           if (TYPE_LENGTH (type) < TYPE_LENGTH (builtin_type_int))
 134             type = builtin_type_int;
 135         }
 136       /* Currently all target ABIs require at least the width of an integer
 137          type for an argument.  We may have to conditionalize the following
 138          type coercion for future targets.  */
 139       if (TYPE_LENGTH (type) < TYPE_LENGTH (builtin_type_int))
 140         type = builtin_type_int;
 141       break;
 142     case TYPE_CODE_FLT:
 143       if (!is_prototyped && coerce_float_to_double_p)
 144         {
 145           if (TYPE_LENGTH (type) < TYPE_LENGTH (builtin_type_double))
 146             type = builtin_type_double;
 147           else if (TYPE_LENGTH (type) > TYPE_LENGTH (builtin_type_double))
 148             type = builtin_type_long_double;
 149         }
 150       break;
 151     case TYPE_CODE_FUNC:
 152       type = lookup_pointer_type (type);
 153       break;
 154     case TYPE_CODE_ARRAY:
 155       /* Arrays are coerced to pointers to their first element, unless
 156          they are vectors, in which case we want to leave them alone,
 157          because they are passed by value.  */
 158       if (current_language->c_style_arrays)
 159         if (!TYPE_VECTOR (type))
 160           type = lookup_pointer_type (TYPE_TARGET_TYPE (type));
 161       break;
 162     case TYPE_CODE_UNDEF:
 163     case TYPE_CODE_PTR:
 164     case TYPE_CODE_STRUCT:
 165     case TYPE_CODE_UNION:
 166     case TYPE_CODE_VOID:
 167     case TYPE_CODE_SET:
 168     case TYPE_CODE_RANGE:
 169     case TYPE_CODE_STRING:
 170     case TYPE_CODE_BITSTRING:
 171     case TYPE_CODE_ERROR:
 172     case TYPE_CODE_MEMBERPTR:
 173     case TYPE_CODE_METHODPTR:
 174     case TYPE_CODE_METHOD:
 175     case TYPE_CODE_COMPLEX:
 176     default:
 177       break;
 178     }
 179
 180   return value_cast (type, arg);
 181 }
 182
 183 /* Determine a function's address and its return type from its value.
 184    Calls error() if the function is not valid for calling.  */
 185
 186 CORE_ADDR
 187 find_function_addr (struct value *function, struct type **retval_type)
 188 {
 189   struct type *ftype = check_typedef (value_type (function));
 190   enum type_code code = TYPE_CODE (ftype);
 191   struct type *value_type;
 192   CORE_ADDR funaddr;
 193
 194   /* If it's a member function, just look at the function
 195      part of it.  */
 196
 197   /* Determine address to call.  */
 198   if (code == TYPE_CODE_FUNC || code == TYPE_CODE_METHOD)
 199     {
 200       funaddr = VALUE_ADDRESS (function);
 201       value_type = TYPE_TARGET_TYPE (ftype);
 202     }
 203   else if (code == TYPE_CODE_PTR)
 204     {
 205       funaddr = value_as_address (function);
 206       ftype = check_typedef (TYPE_TARGET_TYPE (ftype));
 207       if (TYPE_CODE (ftype) == TYPE_CODE_FUNC
 208           || TYPE_CODE (ftype) == TYPE_CODE_METHOD)
 209         {
 210           funaddr = gdbarch_convert_from_func_ptr_addr (current_gdbarch,
 211                                                         funaddr,
 212                                                         &current_target);
 213           value_type = TYPE_TARGET_TYPE (ftype);
 214         }
 215       else
 216         value_type = builtin_type_int;
 217     }
 218   else if (code == TYPE_CODE_INT)
 219     {
 220       /* Handle the case of functions lacking debugging info.
 221          Their values are characters since their addresses are char */
 222       if (TYPE_LENGTH (ftype) == 1)
 223         funaddr = value_as_address (value_addr (function));
 224       else
 225         /* Handle integer used as address of a function.  */
 226         funaddr = (CORE_ADDR) value_as_long (function);
 227
 228       value_type = builtin_type_int;
 229     }
 230   else
 231     error (_("Invalid data type for function to be called."));
 232
 233   if (retval_type != NULL)
 234     *retval_type = value_type;
 235   return funaddr + DEPRECATED_FUNCTION_START_OFFSET;
 236 }
 237
 238 /* Call breakpoint_auto_delete on the current contents of the bpstat
 239    pointed to by arg (which is really a bpstat *).  */
 240
 241 static void
 242 breakpoint_auto_delete_contents (void *arg)
 243 {
 244   breakpoint_auto_delete (*(bpstat *) arg);
 245 }
 246
 247 static CORE_ADDR
 248 generic_push_dummy_code (struct gdbarch *gdbarch,
 249                          CORE_ADDR sp, CORE_ADDR funaddr, int using_gcc,
 250                          struct value **args, int nargs,
 251                          struct type *value_type,
 252                          CORE_ADDR *real_pc, CORE_ADDR *bp_addr,
 253                          struct regcache *regcache)
 254 {
 255   /* Something here to findout the size of a breakpoint and then
 256      allocate space for it on the stack.  */
 257   int bplen;
 258   /* This code assumes frame align.  */
 259   gdb_assert (gdbarch_frame_align_p (gdbarch));
 260   /* Force the stack's alignment.  The intent is to ensure that the SP
 261      is aligned to at least a breakpoint instruction's boundary.  */
 262   sp = gdbarch_frame_align (gdbarch, sp);
 263   /* Allocate space for, and then position the breakpoint on the
 264      stack.  */
 265   if (gdbarch_inner_than (gdbarch, 1, 2))
 266     {
 267       CORE_ADDR bppc = sp;
 268       gdbarch_breakpoint_from_pc (gdbarch, &bppc, &bplen);
 269       sp = gdbarch_frame_align (gdbarch, sp - bplen);
 270       (*bp_addr) = sp;
 271       /* Should the breakpoint size/location be re-computed here?  */
 272     }
 273   else
 274     {
 275       (*bp_addr) = sp;
 276       gdbarch_breakpoint_from_pc (gdbarch, bp_addr, &bplen);
 277       sp = gdbarch_frame_align (gdbarch, sp + bplen);
 278     }
 279   /* Inferior resumes at the function entry point.  */
 280   (*real_pc) = funaddr;
 281   return sp;
 282 }
 283
 284 /* For CALL_DUMMY_ON_STACK, push a breakpoint sequence that the called
 285    function returns to.  */
 286
 287 static CORE_ADDR
 288 push_dummy_code (struct gdbarch *gdbarch,
 289                  CORE_ADDR sp, CORE_ADDR funaddr, int using_gcc,
 290                  struct value **args, int nargs,
 291                  struct type *value_type,
 292                  CORE_ADDR *real_pc, CORE_ADDR *bp_addr,
 293                  struct regcache *regcache)
 294 {
 295   if (gdbarch_push_dummy_code_p (gdbarch))
 296     return gdbarch_push_dummy_code (gdbarch, sp, funaddr, using_gcc,
 297                                     args, nargs, value_type, real_pc, bp_addr,
 298                                     regcache);
 299   else
 300     return generic_push_dummy_code (gdbarch, sp, funaddr, using_gcc,
 301                                     args, nargs, value_type, real_pc, bp_addr,
 302                                     regcache);
 303 }
 304
 305 /* All this stuff with a dummy frame may seem unnecessarily complicated
 306    (why not just save registers in GDB?).  The purpose of pushing a dummy
 307    frame which looks just like a real frame is so that if you call a
 308    function and then hit a breakpoint (get a signal, etc), "backtrace"
 309    will look right.  Whether the backtrace needs to actually show the
 310    stack at the time the inferior function was called is debatable, but
 311    it certainly needs to not display garbage.  So if you are contemplating
 312    making dummy frames be different from normal frames, consider that.  */
 313
 314 /* Perform a function call in the inferior.
 315    ARGS is a vector of values of arguments (NARGS of them).
 316    FUNCTION is a value, the function to be called.
 317    Returns a value representing what the function returned.
 318    May fail to return, if a breakpoint or signal is hit
 319    during the execution of the function.
 320
 321    ARGS is modified to contain coerced values. */
 322
 323 struct value *
 324 call_function_by_hand (struct value *function, int nargs, struct value **args)
 325 {
 326   CORE_ADDR sp;
 327   CORE_ADDR dummy_addr;
 328   struct type *values_type;
 329   unsigned char struct_return;
 330   CORE_ADDR struct_addr = 0;
 331   struct regcache *retbuf;
 332   struct cleanup *retbuf_cleanup;
 333   struct inferior_status *inf_status;
 334   struct cleanup *inf_status_cleanup;
 335   CORE_ADDR funaddr;
 336   int using_gcc;                /* Set to version of gcc in use, or zero if not gcc */
 337   CORE_ADDR real_pc;
 338   struct type *ftype = check_typedef (value_type (function));
 339   CORE_ADDR bp_addr;
 340   struct regcache *caller_regcache;
 341   struct cleanup *caller_regcache_cleanup;
 342   struct frame_id dummy_id;
 343
 344   if (TYPE_CODE (ftype) == TYPE_CODE_PTR)
 345     ftype = check_typedef (TYPE_TARGET_TYPE (ftype));
 346
 347   if (!target_has_execution)
 348     noprocess ();
 349
 350   if (!gdbarch_push_dummy_call_p (current_gdbarch))
 351     error (_("This target does not support function calls"));
 352
 353   /* Create a cleanup chain that contains the retbuf (buffer
 354      containing the register values).  This chain is create BEFORE the
 355      inf_status chain so that the inferior status can cleaned up
 356      (restored or discarded) without having the retbuf freed.  */
 357   retbuf = regcache_xmalloc (current_gdbarch);
 358   retbuf_cleanup = make_cleanup_regcache_xfree (retbuf);
 359
 360   /* A cleanup for the inferior status.  Create this AFTER the retbuf
 361      so that this can be discarded or applied without interfering with
 362      the regbuf.  */
 363   inf_status = save_inferior_status (1);
 364   inf_status_cleanup = make_cleanup_restore_inferior_status (inf_status);
 365
 366   /* Save the caller's registers so that they can be restored once the
 367      callee returns.  To allow nested calls the registers are (further
 368      down) pushed onto a dummy frame stack.  Include a cleanup (which
 369      is tossed once the regcache has been pushed).  */
 370   caller_regcache = frame_save_as_regcache (get_current_frame ());
 371   caller_regcache_cleanup = make_cleanup_regcache_xfree (caller_regcache);
 372
 373   /* Ensure that the initial SP is correctly aligned.  */
 374   {
 375     CORE_ADDR old_sp = get_frame_sp (get_current_frame ());
 376     if (gdbarch_frame_align_p (current_gdbarch))
 377       {
 378         sp = gdbarch_frame_align (current_gdbarch, old_sp);
 379         /* NOTE: cagney/2003-08-13: Skip the "red zone".  For some
 380            ABIs, a function can use memory beyond the inner most stack
 381            address.  AMD64 called that region the "red zone".  Skip at
 382            least the "red zone" size before allocating any space on
 383            the stack.  */
 384         if (gdbarch_inner_than (current_gdbarch, 1, 2))
 385           sp -= gdbarch_frame_red_zone_size (current_gdbarch);
 386         else
 387           sp += gdbarch_frame_red_zone_size (current_gdbarch);
 388         /* Still aligned?  */
 389         gdb_assert (sp == gdbarch_frame_align (current_gdbarch, sp));
 390         /* NOTE: cagney/2002-09-18:
 391
 392            On a RISC architecture, a void parameterless generic dummy
 393            frame (i.e., no parameters, no result) typically does not
 394            need to push anything the stack and hence can leave SP and
 395            FP.  Similarly, a frameless (possibly leaf) function does
 396            not push anything on the stack and, hence, that too can
 397            leave FP and SP unchanged.  As a consequence, a sequence of
 398            void parameterless generic dummy frame calls to frameless
 399            functions will create a sequence of effectively identical
 400            frames (SP, FP and TOS and PC the same).  This, not
 401            suprisingly, results in what appears to be a stack in an
 402            infinite loop --- when GDB tries to find a generic dummy
 403            frame on the internal dummy frame stack, it will always
 404            find the first one.
 405
 406            To avoid this problem, the code below always grows the
 407            stack.  That way, two dummy frames can never be identical.
 408            It does burn a few bytes of stack but that is a small price
 409            to pay :-).  */
 410         if (sp == old_sp)
 411           {
 412             if (gdbarch_inner_than (current_gdbarch, 1, 2))
 413               /* Stack grows down.  */
 414               sp = gdbarch_frame_align (current_gdbarch, old_sp - 1);
 415             else
 416               /* Stack grows up.  */
 417               sp = gdbarch_frame_align (current_gdbarch, old_sp + 1);
 418           }
 419         gdb_assert ((gdbarch_inner_than (current_gdbarch, 1, 2)
 420                     && sp <= old_sp)
 421                     || (gdbarch_inner_than (current_gdbarch, 2, 1)
 422                        && sp >= old_sp));
 423       }
 424     else
 425       /* FIXME: cagney/2002-09-18: Hey, you loose!
 426
 427          Who knows how badly aligned the SP is!
 428
 429          If the generic dummy frame ends up empty (because nothing is
 430          pushed) GDB won't be able to correctly perform back traces.
 431          If a target is having trouble with backtraces, first thing to
 432          do is add FRAME_ALIGN() to the architecture vector. If that
 433          fails, try unwind_dummy_id().
 434
 435          If the ABI specifies a "Red Zone" (see the doco) the code
 436          below will quietly trash it.  */
 437       sp = old_sp;
 438   }
 439
 440   funaddr = find_function_addr (function, &values_type);
 441   CHECK_TYPEDEF (values_type);
 442
 443   {
 444     struct block *b = block_for_pc (funaddr);
 445     /* If compiled without -g, assume GCC 2.  */
 446     using_gcc = (b == NULL ? 2 : BLOCK_GCC_COMPILED (b));
 447   }
 448
 449   /* Are we returning a value using a structure return or a normal
 450      value return? */
 451
 452   struct_return = using_struct_return (values_type, using_gcc);
 453
 454   /* Determine the location of the breakpoint (and possibly other
 455      stuff) that the called function will return to.  The SPARC, for a
 456      function returning a structure or union, needs to make space for
 457      not just the breakpoint but also an extra word containing the
 458      size (?) of the structure being passed.  */
 459
 460   /* The actual breakpoint (at BP_ADDR) is inserted separatly so there
 461      is no need to write that out.  */
 462
 463   switch (gdbarch_call_dummy_location (current_gdbarch))
 464     {
 465     case ON_STACK:
 466       /* "dummy_addr" is here just to keep old targets happy.  New
 467          targets return that same information via "sp" and "bp_addr".  */
 468       if (gdbarch_inner_than (current_gdbarch, 1, 2))
 469         {
 470           sp = push_dummy_code (current_gdbarch, sp, funaddr,
 471                                 using_gcc, args, nargs, values_type,
 472                                 &real_pc, &bp_addr, get_current_regcache ());
 473           dummy_addr = sp;
 474         }
 475       else
 476         {
 477           dummy_addr = sp;
 478           sp = push_dummy_code (current_gdbarch, sp, funaddr,
 479                                 using_gcc, args, nargs, values_type,
 480                                 &real_pc, &bp_addr, get_current_regcache ());
 481         }
 482       break;
 483     case AT_ENTRY_POINT:
 484       real_pc = funaddr;
 485       dummy_addr = entry_point_address ();
 486       /* Make certain that the address points at real code, and not a
 487          function descriptor.  */
 488       dummy_addr = gdbarch_convert_from_func_ptr_addr (current_gdbarch,
 489                                                        dummy_addr,
 490                                                        &current_target);
 491       /* A call dummy always consists of just a single breakpoint, so
 492          it's address is the same as the address of the dummy.  */
 493       bp_addr = dummy_addr;
 494       break;
 495     case AT_SYMBOL:
 496       /* Some executables define a symbol __CALL_DUMMY_ADDRESS whose
 497          address is the location where the breakpoint should be
 498          placed.  Once all targets are using the overhauled frame code
 499          this can be deleted - ON_STACK is a better option.  */
 500       {
 501         struct minimal_symbol *sym;
 502
 503         sym = lookup_minimal_symbol ("__CALL_DUMMY_ADDRESS", NULL, NULL);
 504         real_pc = funaddr;
 505         if (sym)
 506           dummy_addr = SYMBOL_VALUE_ADDRESS (sym);
 507         else
 508           dummy_addr = entry_point_address ();
 509         /* Make certain that the address points at real code, and not
 510            a function descriptor.  */
 511         dummy_addr = gdbarch_convert_from_func_ptr_addr (current_gdbarch,
 512                                                          dummy_addr,
 513                                                          &current_target);
 514         /* A call dummy always consists of just a single breakpoint,
 515            so it's address is the same as the address of the dummy.  */
 516         bp_addr = dummy_addr;
 517         break;
 518       }
 519     default:
 520       internal_error (__FILE__, __LINE__, _("bad switch"));
 521     }
 522
 523   if (nargs < TYPE_NFIELDS (ftype))
 524     error (_("too few arguments in function call"));
 525
 526   {
 527     int i;
 528     for (i = nargs - 1; i >= 0; i--)
 529       {
 530         int prototyped;
 531         struct type *param_type;
 532
 533         /* FIXME drow/2002-05-31: Should just always mark methods as
 534            prototyped.  Can we respect TYPE_VARARGS?  Probably not.  */
 535         if (TYPE_CODE (ftype) == TYPE_CODE_METHOD)
 536           prototyped = 1;
 537         else if (i < TYPE_NFIELDS (ftype))
 538           prototyped = TYPE_PROTOTYPED (ftype);
 539         else
 540           prototyped = 0;
 541
 542         if (i < TYPE_NFIELDS (ftype))
 543           param_type = TYPE_FIELD_TYPE (ftype, i);
 544         else
 545           param_type = NULL;
 546
 547         args[i] = value_arg_coerce (args[i], param_type, prototyped);
 548
 549         /* elz: this code is to handle the case in which the function
 550            to be called has a pointer to function as parameter and the
 551            corresponding actual argument is the address of a function
 552            and not a pointer to function variable.  In aCC compiled
 553            code, the calls through pointers to functions (in the body
 554            of the function called by hand) are made via
 555            $$dyncall_external which requires some registers setting,
 556            this is taken care of if we call via a function pointer
 557            variable, but not via a function address.  In cc this is
 558            not a problem. */
 559
 560         if (using_gcc == 0)
 561           {
 562             if (param_type != NULL && TYPE_CODE (ftype) != TYPE_CODE_METHOD)
 563               {
 564                 /* if this parameter is a pointer to function.  */
 565                 if (TYPE_CODE (param_type) == TYPE_CODE_PTR)
 566                   if (TYPE_CODE (TYPE_TARGET_TYPE (param_type)) == TYPE_CODE_FUNC)
 567                     /* elz: FIXME here should go the test about the
 568                        compiler used to compile the target. We want to
 569                        issue the error message only if the compiler
 570                        used was HP's aCC.  If we used HP's cc, then
 571                        there is no problem and no need to return at
 572                        this point.  */
 573                     /* Go see if the actual parameter is a variable of
 574                        type pointer to function or just a function.  */
 575                     if (VALUE_LVAL (args[i]) == not_lval)
 576                       {
 577                         char *arg_name;
 578                         /* NOTE: cagney/2005-01-02: THIS IS BOGUS.  */
 579                         if (find_pc_partial_function ((CORE_ADDR) value_contents (args[i])[0], &arg_name, NULL, NULL))
 580                           error (_("\
 581 You cannot use function <%s> as argument. \n\
 582 You must use a pointer to function type variable. Command ignored."), arg_name);
 583                       }
 584               }
 585           }
 586       }
 587   }
 588
 589   if (DEPRECATED_REG_STRUCT_HAS_ADDR_P ())
 590     {
 591       int i;
 592       /* This is a machine like the sparc, where we may need to pass a
 593          pointer to the structure, not the structure itself.  */
 594       for (i = nargs - 1; i >= 0; i--)
 595         {
 596           struct type *arg_type = check_typedef (value_type (args[i]));
 597           if ((TYPE_CODE (arg_type) == TYPE_CODE_STRUCT
 598                || TYPE_CODE (arg_type) == TYPE_CODE_UNION
 599                || TYPE_CODE (arg_type) == TYPE_CODE_ARRAY
 600                || TYPE_CODE (arg_type) == TYPE_CODE_STRING
 601                || TYPE_CODE (arg_type) == TYPE_CODE_BITSTRING
 602                || TYPE_CODE (arg_type) == TYPE_CODE_SET
 603                || (TYPE_CODE (arg_type) == TYPE_CODE_FLT
 604                    && TYPE_LENGTH (arg_type) > 8)
 605                )
 606               && DEPRECATED_REG_STRUCT_HAS_ADDR (using_gcc, arg_type))
 607             {
 608               CORE_ADDR addr;
 609               int len;          /*  = TYPE_LENGTH (arg_type); */
 610               int aligned_len;
 611               arg_type = check_typedef (value_enclosing_type (args[i]));
 612               len = TYPE_LENGTH (arg_type);
 613
 614               aligned_len = len;
 615               if (gdbarch_inner_than (current_gdbarch, 1, 2))
 616                 {
 617                   /* stack grows downward */
 618                   sp -= aligned_len;
 619                   /* ... so the address of the thing we push is the
 620                      stack pointer after we push it.  */
 621                   addr = sp;
 622                 }
 623               else
 624                 {
 625                   /* The stack grows up, so the address of the thing
 626                      we push is the stack pointer before we push it.  */
 627                   addr = sp;
 628                   sp += aligned_len;
 629                 }
 630               /* Push the structure.  */
 631               write_memory (addr, value_contents_all (args[i]), len);
 632               /* The value we're going to pass is the address of the
 633                  thing we just pushed.  */
 634               /*args[i] = value_from_longest (lookup_pointer_type (values_type),
 635                 (LONGEST) addr); */
 636               args[i] = value_from_pointer (lookup_pointer_type (arg_type),
 637                                             addr);
 638             }
 639         }
 640     }
 641
 642
 643   /* Reserve space for the return structure to be written on the
 644      stack, if necessary.  Make certain that the value is correctly
 645      aligned. */
 646
 647   if (struct_return)
 648     {
 649       int len = TYPE_LENGTH (values_type);
 650       if (gdbarch_inner_than (current_gdbarch, 1, 2))
 651         {
 652           /* Stack grows downward.  Align STRUCT_ADDR and SP after
 653              making space for the return value.  */
 654           sp -= len;
 655           if (gdbarch_frame_align_p (current_gdbarch))
 656             sp = gdbarch_frame_align (current_gdbarch, sp);
 657           struct_addr = sp;
 658         }
 659       else
 660         {
 661           /* Stack grows upward.  Align the frame, allocate space, and
 662              then again, re-align the frame??? */
 663           if (gdbarch_frame_align_p (current_gdbarch))
 664             sp = gdbarch_frame_align (current_gdbarch, sp);
 665           struct_addr = sp;
 666           sp += len;
 667           if (gdbarch_frame_align_p (current_gdbarch))
 668             sp = gdbarch_frame_align (current_gdbarch, sp);
 669         }
 670     }
 671
 672   /* Create the dummy stack frame.  Pass in the call dummy address as,
 673      presumably, the ABI code knows where, in the call dummy, the
 674      return address should be pointed.  */
 675   sp = gdbarch_push_dummy_call (current_gdbarch, function,
 676                                 get_current_regcache (), bp_addr, nargs, args,
 677                                 sp, struct_return, struct_addr);
 678
 679   /* Set up a frame ID for the dummy frame so we can pass it to
 680      set_momentary_breakpoint.  We need to give the breakpoint a frame
 681      ID so that the breakpoint code can correctly re-identify the
 682      dummy breakpoint.  */
 683   /* Sanity.  The exact same SP value is returned by PUSH_DUMMY_CALL,
 684      saved as the dummy-frame TOS, and used by unwind_dummy_id to form
 685      the frame ID's stack address.  */
 686   dummy_id = frame_id_build (sp, bp_addr);
 687
 688   /* Create a momentary breakpoint at the return address of the
 689      inferior.  That way it breaks when it returns.  */
 690
 691   {
 692     struct breakpoint *bpt;
 693     struct symtab_and_line sal;
 694     init_sal (&sal);            /* initialize to zeroes */
 695     sal.pc = bp_addr;
 696     sal.section = find_pc_overlay (sal.pc);
 697     /* Sanity.  The exact same SP value is returned by
 698        PUSH_DUMMY_CALL, saved as the dummy-frame TOS, and used by
 699        unwind_dummy_id to form the frame ID's stack address.  */
 700     bpt = set_momentary_breakpoint (sal, dummy_id, bp_call_dummy);
 701     bpt->disposition = disp_del;
 702   }
 703
 704   /* Everything's ready, push all the info needed to restore the
 705      caller (and identify the dummy-frame) onto the dummy-frame
 706      stack.  */
 707   dummy_frame_push (caller_regcache, &dummy_id);
 708   discard_cleanups (caller_regcache_cleanup);
 709
 710   /* - SNIP - SNIP - SNIP - SNIP - SNIP - SNIP - SNIP - SNIP - SNIP -
 711      If you're looking to implement asynchronous dummy-frames, then
 712      just below is the place to chop this function in two..  */
 713
 714   /* Now proceed, having reached the desired place.  */
 715   clear_proceed_status ();
 716
 717   /* Execute a "stack dummy", a piece of code stored in the stack by
 718      the debugger to be executed in the inferior.
 719
 720      The dummy's frame is automatically popped whenever that break is
 721      hit.  If that is the first time the program stops,
 722      call_function_by_hand returns to its caller with that frame
 723      already gone and sets RC to 0.
 724
 725      Otherwise, set RC to a non-zero value.  If the called function
 726      receives a random signal, we do not allow the user to continue
 727      executing it as this may not work.  The dummy frame is poped and
 728      we return 1.  If we hit a breakpoint, we leave the frame in place
 729      and return 2 (the frame will eventually be popped when we do hit
 730      the dummy end breakpoint).  */
 731
 732   {
 733     struct cleanup *old_cleanups = make_cleanup (null_cleanup, 0);
 734     int saved_async = 0;
 735
 736     /* If all error()s out of proceed ended up calling normal_stop
 737        (and perhaps they should; it already does in the special case
 738        of error out of resume()), then we wouldn't need this.  */
 739     make_cleanup (breakpoint_auto_delete_contents, &stop_bpstat);
 740
 741     disable_watchpoints_before_interactive_call_start ();
 742     proceed_to_finish = 1;      /* We want stop_registers, please... */
 743
 744     if (target_can_async_p ())
 745       saved_async = target_async_mask (0);
 746
 747     proceed (real_pc, TARGET_SIGNAL_0, 0);
 748
 749     if (saved_async)
 750       target_async_mask (saved_async);
 751
 752     enable_watchpoints_after_interactive_call_stop ();
 753
 754     discard_cleanups (old_cleanups);
 755   }
 756
 757   if (stopped_by_random_signal || !stop_stack_dummy)
 758     {
 759       /* Find the name of the function we're about to complain about.  */
 760       const char *name = NULL;
 761       {
 762         struct symbol *symbol = find_pc_function (funaddr);
 763         if (symbol)
 764           name = SYMBOL_PRINT_NAME (symbol);
 765         else
 766           {
 767             /* Try the minimal symbols.  */
 768             struct minimal_symbol *msymbol = lookup_minimal_symbol_by_pc (funaddr);
 769             if (msymbol)
 770               name = SYMBOL_PRINT_NAME (msymbol);
 771           }
 772         if (name == NULL)
 773           {
 774             /* Can't use a cleanup here.  It is discarded, instead use
 775                an alloca.  */
 776             char *tmp = xstrprintf ("at %s", hex_string (funaddr));
 777             char *a = alloca (strlen (tmp) + 1);
 778             strcpy (a, tmp);
 779             xfree (tmp);
 780             name = a;
 781           }
 782       }
 783       if (stopped_by_random_signal)
 784         {
 785           /* We stopped inside the FUNCTION because of a random
 786              signal.  Further execution of the FUNCTION is not
 787              allowed. */
 788
 789           if (unwind_on_signal_p)
 790             {
 791               /* The user wants the context restored. */
 792
 793               /* We must get back to the frame we were before the
 794                  dummy call. */
 795               frame_pop (get_current_frame ());
 796
 797               /* FIXME: Insert a bunch of wrap_here; name can be very
 798                  long if it's a C++ name with arguments and stuff.  */
 799               error (_("\
 800 The program being debugged was signaled while in a function called from GDB.\n\
 801 GDB has restored the context to what it was before the call.\n\
 802 To change this behavior use \"set unwindonsignal off\"\n\
 803 Evaluation of the expression containing the function (%s) will be abandoned."),
 804                      name);
 805             }
 806           else
 807             {
 808               /* The user wants to stay in the frame where we stopped
 809                  (default).*/
 810               /* If we restored the inferior status (via the cleanup),
 811                  we would print a spurious error message (Unable to
 812                  restore previously selected frame), would write the
 813                  registers from the inf_status (which is wrong), and
 814                  would do other wrong things.  */
 815               discard_cleanups (inf_status_cleanup);
 816               discard_inferior_status (inf_status);
 817               /* FIXME: Insert a bunch of wrap_here; name can be very
 818                  long if it's a C++ name with arguments and stuff.  */
 819               error (_("\
 820 The program being debugged was signaled while in a function called from GDB.\n\
 821 GDB remains in the frame where the signal was received.\n\
 822 To change this behavior use \"set unwindonsignal on\"\n\
 823 Evaluation of the expression containing the function (%s) will be abandoned."),
 824                      name);
 825             }
 826         }
 827
 828       if (!stop_stack_dummy)
 829         {
 830           /* We hit a breakpoint inside the FUNCTION. */
 831           /* If we restored the inferior status (via the cleanup), we
 832              would print a spurious error message (Unable to restore
 833              previously selected frame), would write the registers
 834              from the inf_status (which is wrong), and would do other
 835              wrong things.  */
 836           discard_cleanups (inf_status_cleanup);
 837           discard_inferior_status (inf_status);
 838           /* The following error message used to say "The expression
 839              which contained the function call has been discarded."
 840              It is a hard concept to explain in a few words.  Ideally,
 841              GDB would be able to resume evaluation of the expression
 842              when the function finally is done executing.  Perhaps
 843              someday this will be implemented (it would not be easy).  */
 844           /* FIXME: Insert a bunch of wrap_here; name can be very long if it's
 845              a C++ name with arguments and stuff.  */
 846           error (_("\
 847 The program being debugged stopped while in a function called from GDB.\n\
 848 When the function (%s) is done executing, GDB will silently\n\
 849 stop (instead of continuing to evaluate the expression containing\n\
 850 the function call)."), name);
 851         }
 852
 853       /* The above code errors out, so ...  */
 854       internal_error (__FILE__, __LINE__, _("... should not be here"));
 855     }
 856
 857   /* If we get here the called FUNCTION run to completion. */
 858
 859   /* On normal return, the stack dummy has been popped already.  */
 860   regcache_cpy_no_passthrough (retbuf, stop_registers);
 861
 862   /* Restore the inferior status, via its cleanup.  At this stage,
 863      leave the RETBUF alone.  */
 864   do_cleanups (inf_status_cleanup);
 865
 866   /* Figure out the value returned by the function.  */
 867   {
 868     struct value *retval = NULL;
 869
 870     if (TYPE_CODE (values_type) == TYPE_CODE_VOID)
 871       {
 872         /* If the function returns void, don't bother fetching the
 873            return value.  */
 874         retval = allocate_value (values_type);
 875       }
 876     else
 877       {
 878         struct gdbarch *arch = current_gdbarch;
 879
 880         switch (gdbarch_return_value (arch, values_type, NULL, NULL, NULL))
 881           {
 882           case RETURN_VALUE_REGISTER_CONVENTION:
 883           case RETURN_VALUE_ABI_RETURNS_ADDRESS:
 884           case RETURN_VALUE_ABI_PRESERVES_ADDRESS:
 885             retval = allocate_value (values_type);
 886             gdbarch_return_value (current_gdbarch, values_type, retbuf,
 887                                   value_contents_raw (retval), NULL);
 888             break;
 889           case RETURN_VALUE_STRUCT_CONVENTION:
 890             retval = value_at (values_type, struct_addr);
 891             break;
 892           }
 893       }
 894
 895     do_cleanups (retbuf_cleanup);
 896
 897     gdb_assert(retval);
 898     return retval;
 899   }
 900 }
 901 \f
 902
 903 /* Provide a prototype to silence -Wmissing-prototypes.  */
 904 void _initialize_infcall (void);
 905
 906 void
 907 _initialize_infcall (void)
 908 {
 909   add_setshow_boolean_cmd ("coerce-float-to-double", class_obscure,
 910                            &coerce_float_to_double_p, _("\
 911 Set coercion of floats to doubles when calling functions."), _("\
 912 Show coercion of floats to doubles when calling functions"), _("\
 913 Variables of type float should generally be converted to doubles before\n\
 914 calling an unprototyped function, and left alone when calling a prototyped\n\
 915 function.  However, some older debug info formats do not provide enough\n\
 916 information to determine that a function is prototyped.  If this flag is\n\
 917 set, GDB will perform the conversion for a function it considers\n\
 918 unprototyped.\n\
 919 The default is to perform the conversion.\n"),
 920                            NULL,
 921                            show_coerce_float_to_double_p,
 922                            &setlist, &showlist);
 923
 924   add_setshow_boolean_cmd ("unwindonsignal", no_class,
 925                            &unwind_on_signal_p, _("\
 926 Set unwinding of stack if a signal is received while in a call dummy."), _("\
 927 Show unwinding of stack if a signal is received while in a call dummy."), _("\
 928 The unwindonsignal lets the user determine what gdb should do if a signal\n\
 929 is received while in a function called from gdb (call dummy).  If set, gdb\n\
 930 unwinds the stack and restore the context to what as it was before the call.\n\
 931 The default is to stop in the frame where the signal was received."),
 932                            NULL,
 933                            show_unwind_on_signal_p,
 934                            &setlist, &showlist);
 935 }