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,
   4    1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005
   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_MEMBER:
 173     case TYPE_CODE_METHOD:
 174     case TYPE_CODE_COMPLEX:
 175     default:
 176       break;
 177     }
 178
 179   return value_cast (type, arg);
 180 }
 181
 182 /* Determine a function's address and its return type from its value.
 183    Calls error() if the function is not valid for calling.  */
 184
 185 CORE_ADDR
 186 find_function_addr (struct value *function, struct type **retval_type)
 187 {
 188   struct type *ftype = check_typedef (value_type (function));
 189   enum type_code code = TYPE_CODE (ftype);
 190   struct type *value_type;
 191   CORE_ADDR funaddr;
 192
 193   /* If it's a member function, just look at the function
 194      part of it.  */
 195
 196   /* Determine address to call.  */
 197   if (code == TYPE_CODE_FUNC || code == TYPE_CODE_METHOD)
 198     {
 199       funaddr = VALUE_ADDRESS (function);
 200       value_type = TYPE_TARGET_TYPE (ftype);
 201     }
 202   else if (code == TYPE_CODE_PTR)
 203     {
 204       funaddr = value_as_address (function);
 205       ftype = check_typedef (TYPE_TARGET_TYPE (ftype));
 206       if (TYPE_CODE (ftype) == TYPE_CODE_FUNC
 207           || TYPE_CODE (ftype) == TYPE_CODE_METHOD)
 208         {
 209           funaddr = gdbarch_convert_from_func_ptr_addr (current_gdbarch,
 210                                                         funaddr,
 211                                                         &current_target);
 212           value_type = TYPE_TARGET_TYPE (ftype);
 213         }
 214       else
 215         value_type = builtin_type_int;
 216     }
 217   else if (code == TYPE_CODE_INT)
 218     {
 219       /* Handle the case of functions lacking debugging info.
 220          Their values are characters since their addresses are char */
 221       if (TYPE_LENGTH (ftype) == 1)
 222         funaddr = value_as_address (value_addr (function));
 223       else
 224         /* Handle integer used as address of a function.  */
 225         funaddr = (CORE_ADDR) value_as_long (function);
 226
 227       value_type = builtin_type_int;
 228     }
 229   else
 230     error (_("Invalid data type for function to be called."));
 231
 232   if (retval_type != NULL)
 233     *retval_type = value_type;
 234   return funaddr + DEPRECATED_FUNCTION_START_OFFSET;
 235 }
 236
 237 /* Call breakpoint_auto_delete on the current contents of the bpstat
 238    pointed to by arg (which is really a bpstat *).  */
 239
 240 static void
 241 breakpoint_auto_delete_contents (void *arg)
 242 {
 243   breakpoint_auto_delete (*(bpstat *) arg);
 244 }
 245
 246 static CORE_ADDR
 247 generic_push_dummy_code (struct gdbarch *gdbarch,
 248                          CORE_ADDR sp, CORE_ADDR funaddr, int using_gcc,
 249                          struct value **args, int nargs,
 250                          struct type *value_type,
 251                          CORE_ADDR *real_pc, CORE_ADDR *bp_addr)
 252 {
 253   /* Something here to findout the size of a breakpoint and then
 254      allocate space for it on the stack.  */
 255   int bplen;
 256   /* This code assumes frame align.  */
 257   gdb_assert (gdbarch_frame_align_p (gdbarch));
 258   /* Force the stack's alignment.  The intent is to ensure that the SP
 259      is aligned to at least a breakpoint instruction's boundary.  */
 260   sp = gdbarch_frame_align (gdbarch, sp);
 261   /* Allocate space for, and then position the breakpoint on the
 262      stack.  */
 263   if (gdbarch_inner_than (gdbarch, 1, 2))
 264     {
 265       CORE_ADDR bppc = sp;
 266       gdbarch_breakpoint_from_pc (gdbarch, &bppc, &bplen);
 267       sp = gdbarch_frame_align (gdbarch, sp - bplen);
 268       (*bp_addr) = sp;
 269       /* Should the breakpoint size/location be re-computed here?  */
 270     }
 271   else
 272     {
 273       (*bp_addr) = sp;
 274       gdbarch_breakpoint_from_pc (gdbarch, bp_addr, &bplen);
 275       sp = gdbarch_frame_align (gdbarch, sp + bplen);
 276     }
 277   /* Inferior resumes at the function entry point.  */
 278   (*real_pc) = funaddr;
 279   return sp;
 280 }
 281
 282 /* For CALL_DUMMY_ON_STACK, push a breakpoint sequence that the called
 283    function returns to.  */
 284
 285 static CORE_ADDR
 286 push_dummy_code (struct gdbarch *gdbarch,
 287                  CORE_ADDR sp, CORE_ADDR funaddr, int using_gcc,
 288                  struct value **args, int nargs,
 289                  struct type *value_type,
 290                  CORE_ADDR *real_pc, CORE_ADDR *bp_addr)
 291 {
 292   if (gdbarch_push_dummy_code_p (gdbarch))
 293     return gdbarch_push_dummy_code (gdbarch, sp, funaddr, using_gcc,
 294                                     args, nargs, value_type, real_pc, bp_addr);
 295   else
 296     return generic_push_dummy_code (gdbarch, sp, funaddr, using_gcc,
 297                                     args, nargs, value_type, real_pc, bp_addr);
 298 }
 299
 300 /* All this stuff with a dummy frame may seem unnecessarily complicated
 301    (why not just save registers in GDB?).  The purpose of pushing a dummy
 302    frame which looks just like a real frame is so that if you call a
 303    function and then hit a breakpoint (get a signal, etc), "backtrace"
 304    will look right.  Whether the backtrace needs to actually show the
 305    stack at the time the inferior function was called is debatable, but
 306    it certainly needs to not display garbage.  So if you are contemplating
 307    making dummy frames be different from normal frames, consider that.  */
 308
 309 /* Perform a function call in the inferior.
 310    ARGS is a vector of values of arguments (NARGS of them).
 311    FUNCTION is a value, the function to be called.
 312    Returns a value representing what the function returned.
 313    May fail to return, if a breakpoint or signal is hit
 314    during the execution of the function.
 315
 316    ARGS is modified to contain coerced values. */
 317
 318 struct value *
 319 call_function_by_hand (struct value *function, int nargs, struct value **args)
 320 {
 321   CORE_ADDR sp;
 322   CORE_ADDR dummy_addr;
 323   struct type *values_type;
 324   unsigned char struct_return;
 325   CORE_ADDR struct_addr = 0;
 326   struct regcache *retbuf;
 327   struct cleanup *retbuf_cleanup;
 328   struct inferior_status *inf_status;
 329   struct cleanup *inf_status_cleanup;
 330   CORE_ADDR funaddr;
 331   int using_gcc;                /* Set to version of gcc in use, or zero if not gcc */
 332   CORE_ADDR real_pc;
 333   struct type *ftype = check_typedef (value_type (function));
 334   CORE_ADDR bp_addr;
 335   struct regcache *caller_regcache;
 336   struct cleanup *caller_regcache_cleanup;
 337   struct frame_id dummy_id;
 338
 339   if (!target_has_execution)
 340     noprocess ();
 341
 342   if (!gdbarch_push_dummy_call_p (current_gdbarch))
 343     error (_("This target does not support function calls"));
 344
 345   /* Create a cleanup chain that contains the retbuf (buffer
 346      containing the register values).  This chain is create BEFORE the
 347      inf_status chain so that the inferior status can cleaned up
 348      (restored or discarded) without having the retbuf freed.  */
 349   retbuf = regcache_xmalloc (current_gdbarch);
 350   retbuf_cleanup = make_cleanup_regcache_xfree (retbuf);
 351
 352   /* A cleanup for the inferior status.  Create this AFTER the retbuf
 353      so that this can be discarded or applied without interfering with
 354      the regbuf.  */
 355   inf_status = save_inferior_status (1);
 356   inf_status_cleanup = make_cleanup_restore_inferior_status (inf_status);
 357
 358   /* Save the caller's registers so that they can be restored once the
 359      callee returns.  To allow nested calls the registers are (further
 360      down) pushed onto a dummy frame stack.  Include a cleanup (which
 361      is tossed once the regcache has been pushed).  */
 362   caller_regcache = frame_save_as_regcache (get_current_frame ());
 363   caller_regcache_cleanup = make_cleanup_regcache_xfree (caller_regcache);
 364
 365   /* Ensure that the initial SP is correctly aligned.  */
 366   {
 367     CORE_ADDR old_sp = read_sp ();
 368     if (gdbarch_frame_align_p (current_gdbarch))
 369       {
 370         sp = gdbarch_frame_align (current_gdbarch, old_sp);
 371         /* NOTE: cagney/2003-08-13: Skip the "red zone".  For some
 372            ABIs, a function can use memory beyond the inner most stack
 373            address.  AMD64 called that region the "red zone".  Skip at
 374            least the "red zone" size before allocating any space on
 375            the stack.  */
 376         if (INNER_THAN (1, 2))
 377           sp -= gdbarch_frame_red_zone_size (current_gdbarch);
 378         else
 379           sp += gdbarch_frame_red_zone_size (current_gdbarch);
 380         /* Still aligned?  */
 381         gdb_assert (sp == gdbarch_frame_align (current_gdbarch, sp));
 382         /* NOTE: cagney/2002-09-18:
 383
 384            On a RISC architecture, a void parameterless generic dummy
 385            frame (i.e., no parameters, no result) typically does not
 386            need to push anything the stack and hence can leave SP and
 387            FP.  Similarly, a frameless (possibly leaf) function does
 388            not push anything on the stack and, hence, that too can
 389            leave FP and SP unchanged.  As a consequence, a sequence of
 390            void parameterless generic dummy frame calls to frameless
 391            functions will create a sequence of effectively identical
 392            frames (SP, FP and TOS and PC the same).  This, not
 393            suprisingly, results in what appears to be a stack in an
 394            infinite loop --- when GDB tries to find a generic dummy
 395            frame on the internal dummy frame stack, it will always
 396            find the first one.
 397
 398            To avoid this problem, the code below always grows the
 399            stack.  That way, two dummy frames can never be identical.
 400            It does burn a few bytes of stack but that is a small price
 401            to pay :-).  */
 402         if (sp == old_sp)
 403           {
 404             if (INNER_THAN (1, 2))
 405               /* Stack grows down.  */
 406               sp = gdbarch_frame_align (current_gdbarch, old_sp - 1);
 407             else
 408               /* Stack grows up.  */
 409               sp = gdbarch_frame_align (current_gdbarch, old_sp + 1);
 410           }
 411         gdb_assert ((INNER_THAN (1, 2) && sp <= old_sp)
 412                     || (INNER_THAN (2, 1) && sp >= old_sp));
 413       }
 414     else
 415       /* FIXME: cagney/2002-09-18: Hey, you loose!
 416
 417          Who knows how badly aligned the SP is!
 418
 419          If the generic dummy frame ends up empty (because nothing is
 420          pushed) GDB won't be able to correctly perform back traces.
 421          If a target is having trouble with backtraces, first thing to
 422          do is add FRAME_ALIGN() to the architecture vector. If that
 423          fails, try unwind_dummy_id().
 424
 425          If the ABI specifies a "Red Zone" (see the doco) the code
 426          below will quietly trash it.  */
 427       sp = old_sp;
 428   }
 429
 430   funaddr = find_function_addr (function, &values_type);
 431   CHECK_TYPEDEF (values_type);
 432
 433   {
 434     struct block *b = block_for_pc (funaddr);
 435     /* If compiled without -g, assume GCC 2.  */
 436     using_gcc = (b == NULL ? 2 : BLOCK_GCC_COMPILED (b));
 437   }
 438
 439   /* Are we returning a value using a structure return or a normal
 440      value return? */
 441
 442   struct_return = using_struct_return (values_type, using_gcc);
 443
 444   /* Determine the location of the breakpoint (and possibly other
 445      stuff) that the called function will return to.  The SPARC, for a
 446      function returning a structure or union, needs to make space for
 447      not just the breakpoint but also an extra word containing the
 448      size (?) of the structure being passed.  */
 449
 450   /* The actual breakpoint (at BP_ADDR) is inserted separatly so there
 451      is no need to write that out.  */
 452
 453   switch (CALL_DUMMY_LOCATION)
 454     {
 455     case ON_STACK:
 456       /* "dummy_addr" is here just to keep old targets happy.  New
 457          targets return that same information via "sp" and "bp_addr".  */
 458       if (INNER_THAN (1, 2))
 459         {
 460           sp = push_dummy_code (current_gdbarch, sp, funaddr,
 461                                 using_gcc, args, nargs, values_type,
 462                                 &real_pc, &bp_addr);
 463           dummy_addr = sp;
 464         }
 465       else
 466         {
 467           dummy_addr = sp;
 468           sp = push_dummy_code (current_gdbarch, sp, funaddr,
 469                                 using_gcc, args, nargs, values_type,
 470                                 &real_pc, &bp_addr);
 471         }
 472       break;
 473     case AT_ENTRY_POINT:
 474       real_pc = funaddr;
 475       dummy_addr = entry_point_address ();
 476       /* Make certain that the address points at real code, and not a
 477          function descriptor.  */
 478       dummy_addr = gdbarch_convert_from_func_ptr_addr (current_gdbarch,
 479                                                        dummy_addr,
 480                                                        &current_target);
 481       /* A call dummy always consists of just a single breakpoint, so
 482          it's address is the same as the address of the dummy.  */
 483       bp_addr = dummy_addr;
 484       break;
 485     case AT_SYMBOL:
 486       /* Some executables define a symbol __CALL_DUMMY_ADDRESS whose
 487          address is the location where the breakpoint should be
 488          placed.  Once all targets are using the overhauled frame code
 489          this can be deleted - ON_STACK is a better option.  */
 490       {
 491         struct minimal_symbol *sym;
 492
 493         sym = lookup_minimal_symbol ("__CALL_DUMMY_ADDRESS", NULL, NULL);
 494         real_pc = funaddr;
 495         if (sym)
 496           dummy_addr = SYMBOL_VALUE_ADDRESS (sym);
 497         else
 498           dummy_addr = entry_point_address ();
 499         /* Make certain that the address points at real code, and not
 500            a function descriptor.  */
 501         dummy_addr = gdbarch_convert_from_func_ptr_addr (current_gdbarch,
 502                                                          dummy_addr,
 503                                                          &current_target);
 504         /* A call dummy always consists of just a single breakpoint,
 505            so it's address is the same as the address of the dummy.  */
 506         bp_addr = dummy_addr;
 507         break;
 508       }
 509     default:
 510       internal_error (__FILE__, __LINE__, _("bad switch"));
 511     }
 512
 513   if (nargs < TYPE_NFIELDS (ftype))
 514     error (_("too few arguments in function call"));
 515
 516   {
 517     int i;
 518     for (i = nargs - 1; i >= 0; i--)
 519       {
 520         int prototyped;
 521         struct type *param_type;
 522
 523         /* FIXME drow/2002-05-31: Should just always mark methods as
 524            prototyped.  Can we respect TYPE_VARARGS?  Probably not.  */
 525         if (TYPE_CODE (ftype) == TYPE_CODE_METHOD)
 526           prototyped = 1;
 527         else if (i < TYPE_NFIELDS (ftype))
 528           prototyped = TYPE_PROTOTYPED (ftype);
 529         else
 530           prototyped = 0;
 531
 532         if (i < TYPE_NFIELDS (ftype))
 533           param_type = TYPE_FIELD_TYPE (ftype, i);
 534         else
 535           param_type = NULL;
 536
 537         args[i] = value_arg_coerce (args[i], param_type, prototyped);
 538
 539         /* elz: this code is to handle the case in which the function
 540            to be called has a pointer to function as parameter and the
 541            corresponding actual argument is the address of a function
 542            and not a pointer to function variable.  In aCC compiled
 543            code, the calls through pointers to functions (in the body
 544            of the function called by hand) are made via
 545            $$dyncall_external which requires some registers setting,
 546            this is taken care of if we call via a function pointer
 547            variable, but not via a function address.  In cc this is
 548            not a problem. */
 549
 550         if (using_gcc == 0)
 551           {
 552             if (param_type != NULL && TYPE_CODE (ftype) != TYPE_CODE_METHOD)
 553               {
 554                 /* if this parameter is a pointer to function.  */
 555                 if (TYPE_CODE (param_type) == TYPE_CODE_PTR)
 556                   if (TYPE_CODE (TYPE_TARGET_TYPE (param_type)) == TYPE_CODE_FUNC)
 557                     /* elz: FIXME here should go the test about the
 558                        compiler used to compile the target. We want to
 559                        issue the error message only if the compiler
 560                        used was HP's aCC.  If we used HP's cc, then
 561                        there is no problem and no need to return at
 562                        this point.  */
 563                     /* Go see if the actual parameter is a variable of
 564                        type pointer to function or just a function.  */
 565                     if (VALUE_LVAL (args[i]) == not_lval)
 566                       {
 567                         char *arg_name;
 568                         /* NOTE: cagney/2005-01-02: THIS IS BOGUS.  */
 569                         if (find_pc_partial_function ((CORE_ADDR) value_contents (args[i])[0], &arg_name, NULL, NULL))
 570                           error (_("\
 571 You cannot use function <%s> as argument. \n\
 572 You must use a pointer to function type variable. Command ignored."), arg_name);
 573                       }
 574               }
 575           }
 576       }
 577   }
 578
 579   if (DEPRECATED_REG_STRUCT_HAS_ADDR_P ())
 580     {
 581       int i;
 582       /* This is a machine like the sparc, where we may need to pass a
 583          pointer to the structure, not the structure itself.  */
 584       for (i = nargs - 1; i >= 0; i--)
 585         {
 586           struct type *arg_type = check_typedef (value_type (args[i]));
 587           if ((TYPE_CODE (arg_type) == TYPE_CODE_STRUCT
 588                || TYPE_CODE (arg_type) == TYPE_CODE_UNION
 589                || TYPE_CODE (arg_type) == TYPE_CODE_ARRAY
 590                || TYPE_CODE (arg_type) == TYPE_CODE_STRING
 591                || TYPE_CODE (arg_type) == TYPE_CODE_BITSTRING
 592                || TYPE_CODE (arg_type) == TYPE_CODE_SET
 593                || (TYPE_CODE (arg_type) == TYPE_CODE_FLT
 594                    && TYPE_LENGTH (arg_type) > 8)
 595                )
 596               && DEPRECATED_REG_STRUCT_HAS_ADDR (using_gcc, arg_type))
 597             {
 598               CORE_ADDR addr;
 599               int len;          /*  = TYPE_LENGTH (arg_type); */
 600               int aligned_len;
 601               arg_type = check_typedef (value_enclosing_type (args[i]));
 602               len = TYPE_LENGTH (arg_type);
 603
 604               aligned_len = len;
 605               if (INNER_THAN (1, 2))
 606                 {
 607                   /* stack grows downward */
 608                   sp -= aligned_len;
 609                   /* ... so the address of the thing we push is the
 610                      stack pointer after we push it.  */
 611                   addr = sp;
 612                 }
 613               else
 614                 {
 615                   /* The stack grows up, so the address of the thing
 616                      we push is the stack pointer before we push it.  */
 617                   addr = sp;
 618                   sp += aligned_len;
 619                 }
 620               /* Push the structure.  */
 621               write_memory (addr, value_contents_all (args[i]), len);
 622               /* The value we're going to pass is the address of the
 623                  thing we just pushed.  */
 624               /*args[i] = value_from_longest (lookup_pointer_type (values_type),
 625                 (LONGEST) addr); */
 626               args[i] = value_from_pointer (lookup_pointer_type (arg_type),
 627                                             addr);
 628             }
 629         }
 630     }
 631
 632
 633   /* Reserve space for the return structure to be written on the
 634      stack, if necessary.  Make certain that the value is correctly
 635      aligned. */
 636
 637   if (struct_return)
 638     {
 639       int len = TYPE_LENGTH (values_type);
 640       if (INNER_THAN (1, 2))
 641         {
 642           /* Stack grows downward.  Align STRUCT_ADDR and SP after
 643              making space for the return value.  */
 644           sp -= len;
 645           if (gdbarch_frame_align_p (current_gdbarch))
 646             sp = gdbarch_frame_align (current_gdbarch, sp);
 647           struct_addr = sp;
 648         }
 649       else
 650         {
 651           /* Stack grows upward.  Align the frame, allocate space, and
 652              then again, re-align the frame??? */
 653           if (gdbarch_frame_align_p (current_gdbarch))
 654             sp = gdbarch_frame_align (current_gdbarch, sp);
 655           struct_addr = sp;
 656           sp += len;
 657           if (gdbarch_frame_align_p (current_gdbarch))
 658             sp = gdbarch_frame_align (current_gdbarch, sp);
 659         }
 660     }
 661
 662   /* Create the dummy stack frame.  Pass in the call dummy address as,
 663      presumably, the ABI code knows where, in the call dummy, the
 664      return address should be pointed.  */
 665   sp = gdbarch_push_dummy_call (current_gdbarch, function, current_regcache,
 666                                 bp_addr, nargs, args, sp, struct_return,
 667                                 struct_addr);
 668
 669   /* Set up a frame ID for the dummy frame so we can pass it to
 670      set_momentary_breakpoint.  We need to give the breakpoint a frame
 671      ID so that the breakpoint code can correctly re-identify the
 672      dummy breakpoint.  */
 673   /* Sanity.  The exact same SP value is returned by PUSH_DUMMY_CALL,
 674      saved as the dummy-frame TOS, and used by unwind_dummy_id to form
 675      the frame ID's stack address.  */
 676   dummy_id = frame_id_build (sp, bp_addr);
 677
 678   /* Create a momentary breakpoint at the return address of the
 679      inferior.  That way it breaks when it returns.  */
 680
 681   {
 682     struct breakpoint *bpt;
 683     struct symtab_and_line sal;
 684     init_sal (&sal);            /* initialize to zeroes */
 685     sal.pc = bp_addr;
 686     sal.section = find_pc_overlay (sal.pc);
 687     /* Sanity.  The exact same SP value is returned by
 688        PUSH_DUMMY_CALL, saved as the dummy-frame TOS, and used by
 689        unwind_dummy_id to form the frame ID's stack address.  */
 690     bpt = set_momentary_breakpoint (sal, dummy_id, bp_call_dummy);
 691     bpt->disposition = disp_del;
 692   }
 693
 694   /* Everything's ready, push all the info needed to restore the
 695      caller (and identify the dummy-frame) onto the dummy-frame
 696      stack.  */
 697   dummy_frame_push (caller_regcache, &dummy_id);
 698   discard_cleanups (caller_regcache_cleanup);
 699
 700   /* - SNIP - SNIP - SNIP - SNIP - SNIP - SNIP - SNIP - SNIP - SNIP -
 701      If you're looking to implement asynchronous dummy-frames, then
 702      just below is the place to chop this function in two..  */
 703
 704   /* Now proceed, having reached the desired place.  */
 705   clear_proceed_status ();
 706
 707   /* Execute a "stack dummy", a piece of code stored in the stack by
 708      the debugger to be executed in the inferior.
 709
 710      The dummy's frame is automatically popped whenever that break is
 711      hit.  If that is the first time the program stops,
 712      call_function_by_hand returns to its caller with that frame
 713      already gone and sets RC to 0.
 714
 715      Otherwise, set RC to a non-zero value.  If the called function
 716      receives a random signal, we do not allow the user to continue
 717      executing it as this may not work.  The dummy frame is poped and
 718      we return 1.  If we hit a breakpoint, we leave the frame in place
 719      and return 2 (the frame will eventually be popped when we do hit
 720      the dummy end breakpoint).  */
 721
 722   {
 723     struct cleanup *old_cleanups = make_cleanup (null_cleanup, 0);
 724     int saved_async = 0;
 725
 726     /* If all error()s out of proceed ended up calling normal_stop
 727        (and perhaps they should; it already does in the special case
 728        of error out of resume()), then we wouldn't need this.  */
 729     make_cleanup (breakpoint_auto_delete_contents, &stop_bpstat);
 730
 731     disable_watchpoints_before_interactive_call_start ();
 732     proceed_to_finish = 1;      /* We want stop_registers, please... */
 733
 734     if (target_can_async_p ())
 735       saved_async = target_async_mask (0);
 736
 737     proceed (real_pc, TARGET_SIGNAL_0, 0);
 738
 739     if (saved_async)
 740       target_async_mask (saved_async);
 741
 742     enable_watchpoints_after_interactive_call_stop ();
 743
 744     discard_cleanups (old_cleanups);
 745   }
 746
 747   if (stopped_by_random_signal || !stop_stack_dummy)
 748     {
 749       /* Find the name of the function we're about to complain about.  */
 750       const char *name = NULL;
 751       {
 752         struct symbol *symbol = find_pc_function (funaddr);
 753         if (symbol)
 754           name = SYMBOL_PRINT_NAME (symbol);
 755         else
 756           {
 757             /* Try the minimal symbols.  */
 758             struct minimal_symbol *msymbol = lookup_minimal_symbol_by_pc (funaddr);
 759             if (msymbol)
 760               name = SYMBOL_PRINT_NAME (msymbol);
 761           }
 762         if (name == NULL)
 763           {
 764             /* Can't use a cleanup here.  It is discarded, instead use
 765                an alloca.  */
 766             char *tmp = xstrprintf ("at %s", hex_string (funaddr));
 767             char *a = alloca (strlen (tmp) + 1);
 768             strcpy (a, tmp);
 769             xfree (tmp);
 770             name = a;
 771           }
 772       }
 773       if (stopped_by_random_signal)
 774         {
 775           /* We stopped inside the FUNCTION because of a random
 776              signal.  Further execution of the FUNCTION is not
 777              allowed. */
 778
 779           if (unwind_on_signal_p)
 780             {
 781               /* The user wants the context restored. */
 782
 783               /* We must get back to the frame we were before the
 784                  dummy call. */
 785               frame_pop (get_current_frame ());
 786
 787               /* FIXME: Insert a bunch of wrap_here; name can be very
 788                  long if it's a C++ name with arguments and stuff.  */
 789               error (_("\
 790 The program being debugged was signaled while in a function called from GDB.\n\
 791 GDB has restored the context to what it was before the call.\n\
 792 To change this behavior use \"set unwindonsignal off\"\n\
 793 Evaluation of the expression containing the function (%s) will be abandoned."),
 794                      name);
 795             }
 796           else
 797             {
 798               /* The user wants to stay in the frame where we stopped
 799                  (default).*/
 800               /* If we restored the inferior status (via the cleanup),
 801                  we would print a spurious error message (Unable to
 802                  restore previously selected frame), would write the
 803                  registers from the inf_status (which is wrong), and
 804                  would do other wrong things.  */
 805               discard_cleanups (inf_status_cleanup);
 806               discard_inferior_status (inf_status);
 807               /* FIXME: Insert a bunch of wrap_here; name can be very
 808                  long if it's a C++ name with arguments and stuff.  */
 809               error (_("\
 810 The program being debugged was signaled while in a function called from GDB.\n\
 811 GDB remains in the frame where the signal was received.\n\
 812 To change this behavior use \"set unwindonsignal on\"\n\
 813 Evaluation of the expression containing the function (%s) will be abandoned."),
 814                      name);
 815             }
 816         }
 817
 818       if (!stop_stack_dummy)
 819         {
 820           /* We hit a breakpoint inside the FUNCTION. */
 821           /* If we restored the inferior status (via the cleanup), we
 822              would print a spurious error message (Unable to restore
 823              previously selected frame), would write the registers
 824              from the inf_status (which is wrong), and would do other
 825              wrong things.  */
 826           discard_cleanups (inf_status_cleanup);
 827           discard_inferior_status (inf_status);
 828           /* The following error message used to say "The expression
 829              which contained the function call has been discarded."
 830              It is a hard concept to explain in a few words.  Ideally,
 831              GDB would be able to resume evaluation of the expression
 832              when the function finally is done executing.  Perhaps
 833              someday this will be implemented (it would not be easy).  */
 834           /* FIXME: Insert a bunch of wrap_here; name can be very long if it's
 835              a C++ name with arguments and stuff.  */
 836           error (_("\
 837 The program being debugged stopped while in a function called from GDB.\n\
 838 When the function (%s) is done executing, GDB will silently\n\
 839 stop (instead of continuing to evaluate the expression containing\n\
 840 the function call)."), name);
 841         }
 842
 843       /* The above code errors out, so ...  */
 844       internal_error (__FILE__, __LINE__, _("... should not be here"));
 845     }
 846
 847   /* If we get here the called FUNCTION run to completion. */
 848
 849   /* On normal return, the stack dummy has been popped already.  */
 850   regcache_cpy_no_passthrough (retbuf, stop_registers);
 851
 852   /* Restore the inferior status, via its cleanup.  At this stage,
 853      leave the RETBUF alone.  */
 854   do_cleanups (inf_status_cleanup);
 855
 856   /* Figure out the value returned by the function.  */
 857   {
 858     struct value *retval = NULL;
 859
 860     if (TYPE_CODE (values_type) == TYPE_CODE_VOID)
 861       {
 862         /* If the function returns void, don't bother fetching the
 863            return value.  */
 864         retval = allocate_value (values_type);
 865       }
 866     else
 867       {
 868         struct gdbarch *arch = current_gdbarch;
 869
 870         switch (gdbarch_return_value (arch, values_type, NULL, NULL, NULL))
 871           {
 872           case RETURN_VALUE_REGISTER_CONVENTION:
 873           case RETURN_VALUE_ABI_RETURNS_ADDRESS:
 874           case RETURN_VALUE_ABI_PRESERVES_ADDRESS:
 875             retval = allocate_value (values_type);
 876             gdbarch_return_value (current_gdbarch, values_type, retbuf,
 877                                   value_contents_raw (retval), NULL);
 878             break;
 879           case RETURN_VALUE_STRUCT_CONVENTION:
 880             retval = value_at (values_type, struct_addr);
 881             break;
 882           }
 883       }
 884
 885     do_cleanups (retbuf_cleanup);
 886
 887     gdb_assert(retval);
 888     return retval;
 889   }
 890 }
 891 \f
 892
 893 /* Provide a prototype to silence -Wmissing-prototypes.  */
 894 void _initialize_infcall (void);
 895
 896 void
 897 _initialize_infcall (void)
 898 {
 899   add_setshow_boolean_cmd ("coerce-float-to-double", class_obscure,
 900                            &coerce_float_to_double_p, _("\
 901 Set coercion of floats to doubles when calling functions."), _("\
 902 Show coercion of floats to doubles when calling functions"), _("\
 903 Variables of type float should generally be converted to doubles before\n\
 904 calling an unprototyped function, and left alone when calling a prototyped\n\
 905 function.  However, some older debug info formats do not provide enough\n\
 906 information to determine that a function is prototyped.  If this flag is\n\
 907 set, GDB will perform the conversion for a function it considers\n\
 908 unprototyped.\n\
 909 The default is to perform the conversion.\n"),
 910                            NULL,
 911                            show_coerce_float_to_double_p,
 912                            &setlist, &showlist);
 913
 914   add_setshow_boolean_cmd ("unwindonsignal", no_class,
 915                            &unwind_on_signal_p, _("\
 916 Set unwinding of stack if a signal is received while in a call dummy."), _("\
 917 Show unwinding of stack if a signal is received while in a call dummy."), _("\
 918 The unwindonsignal lets the user determine what gdb should do if a signal\n\
 919 is received while in a function called from gdb (call dummy).  If set, gdb\n\
 920 unwinds the stack and restore the context to what as it was before the call.\n\
 921 The default is to stop in the frame where the signal was received."),
 922                            NULL,
 923                            show_unwind_on_signal_p,
 924                            &setlist, &showlist);
 925 }