gdb/infcall.c

   1 /* Perform an inferior function call, for GDB, the GNU debugger.
   2
   3    Copyright 1986, 1987, 1988, 1989, 1990, 1991, 1992, 1993, 1994,
   4    1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004
   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., 59 Temple Place - Suite 330,
  22    Boston, MA 02111-1307, 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
  39 /* NOTE: cagney/2003-04-16: What's the future of this code?
  40
  41    GDB needs an asynchronous expression evaluator, that means an
  42    asynchronous inferior function call implementation, and that in
  43    turn means restructuring the code so that it is event driven.  */
  44
  45 /* How you should pass arguments to a function depends on whether it
  46    was defined in K&R style or prototype style.  If you define a
  47    function using the K&R syntax that takes a `float' argument, then
  48    callers must pass that argument as a `double'.  If you define the
  49    function using the prototype syntax, then you must pass the
  50    argument as a `float', with no promotion.
  51
  52    Unfortunately, on certain older platforms, the debug info doesn't
  53    indicate reliably how each function was defined.  A function type's
  54    TYPE_FLAG_PROTOTYPED flag may be clear, even if the function was
  55    defined in prototype style.  When calling a function whose
  56    TYPE_FLAG_PROTOTYPED flag is clear, GDB consults this flag to
  57    decide what to do.
  58
  59    For modern targets, it is proper to assume that, if the prototype
  60    flag is clear, that can be trusted: `float' arguments should be
  61    promoted to `double'.  For some older targets, if the prototype
  62    flag is clear, that doesn't tell us anything.  The default is to
  63    trust the debug information; the user can override this behavior
  64    with "set coerce-float-to-double 0".  */
  65
  66 static int coerce_float_to_double_p = 1;
  67
  68 /* This boolean tells what gdb should do if a signal is received while
  69    in a function called from gdb (call dummy).  If set, gdb unwinds
  70    the stack and restore the context to what as it was before the
  71    call.
  72
  73    The default is to stop in the frame where the signal was received. */
  74
  75 int unwind_on_signal_p = 0;
  76
  77 /* Perform the standard coercions that are specified
  78    for arguments to be passed to C functions.
  79
  80    If PARAM_TYPE is non-NULL, it is the expected parameter type.
  81    IS_PROTOTYPED is non-zero if the function declaration is prototyped.  */
  82
  83 static struct value *
  84 value_arg_coerce (struct value *arg, struct type *param_type,
  85                   int is_prototyped)
  86 {
  87   struct type *arg_type = check_typedef (VALUE_TYPE (arg));
  88   struct type *type
  89     = param_type ? check_typedef (param_type) : arg_type;
  90
  91   switch (TYPE_CODE (type))
  92     {
  93     case TYPE_CODE_REF:
  94       if (TYPE_CODE (arg_type) != TYPE_CODE_REF
  95           && TYPE_CODE (arg_type) != TYPE_CODE_PTR)
  96         {
  97           arg = value_addr (arg);
  98           VALUE_TYPE (arg) = param_type;
  99           return arg;
 100         }
 101       break;
 102     case TYPE_CODE_INT:
 103     case TYPE_CODE_CHAR:
 104     case TYPE_CODE_BOOL:
 105     case TYPE_CODE_ENUM:
 106       /* If we don't have a prototype, coerce to integer type if necessary.  */
 107       if (!is_prototyped)
 108         {
 109           if (TYPE_LENGTH (type) < TYPE_LENGTH (builtin_type_int))
 110             type = builtin_type_int;
 111         }
 112       /* Currently all target ABIs require at least the width of an integer
 113          type for an argument.  We may have to conditionalize the following
 114          type coercion for future targets.  */
 115       if (TYPE_LENGTH (type) < TYPE_LENGTH (builtin_type_int))
 116         type = builtin_type_int;
 117       break;
 118     case TYPE_CODE_FLT:
 119       if (!is_prototyped && coerce_float_to_double_p)
 120         {
 121           if (TYPE_LENGTH (type) < TYPE_LENGTH (builtin_type_double))
 122             type = builtin_type_double;
 123           else if (TYPE_LENGTH (type) > TYPE_LENGTH (builtin_type_double))
 124             type = builtin_type_long_double;
 125         }
 126       break;
 127     case TYPE_CODE_FUNC:
 128       type = lookup_pointer_type (type);
 129       break;
 130     case TYPE_CODE_ARRAY:
 131       /* Arrays are coerced to pointers to their first element, unless
 132          they are vectors, in which case we want to leave them alone,
 133          because they are passed by value.  */
 134       if (current_language->c_style_arrays)
 135         if (!TYPE_VECTOR (type))
 136           type = lookup_pointer_type (TYPE_TARGET_TYPE (type));
 137       break;
 138     case TYPE_CODE_UNDEF:
 139     case TYPE_CODE_PTR:
 140     case TYPE_CODE_STRUCT:
 141     case TYPE_CODE_UNION:
 142     case TYPE_CODE_VOID:
 143     case TYPE_CODE_SET:
 144     case TYPE_CODE_RANGE:
 145     case TYPE_CODE_STRING:
 146     case TYPE_CODE_BITSTRING:
 147     case TYPE_CODE_ERROR:
 148     case TYPE_CODE_MEMBER:
 149     case TYPE_CODE_METHOD:
 150     case TYPE_CODE_COMPLEX:
 151     default:
 152       break;
 153     }
 154
 155   return value_cast (type, arg);
 156 }
 157
 158 /* Determine a function's address and its return type from its value.
 159    Calls error() if the function is not valid for calling.  */
 160
 161 CORE_ADDR
 162 find_function_addr (struct value *function, struct type **retval_type)
 163 {
 164   struct type *ftype = check_typedef (VALUE_TYPE (function));
 165   enum type_code code = TYPE_CODE (ftype);
 166   struct type *value_type;
 167   CORE_ADDR funaddr;
 168
 169   /* If it's a member function, just look at the function
 170      part of it.  */
 171
 172   /* Determine address to call.  */
 173   if (code == TYPE_CODE_FUNC || code == TYPE_CODE_METHOD)
 174     {
 175       funaddr = VALUE_ADDRESS (function);
 176       value_type = TYPE_TARGET_TYPE (ftype);
 177     }
 178   else if (code == TYPE_CODE_PTR)
 179     {
 180       funaddr = value_as_address (function);
 181       ftype = check_typedef (TYPE_TARGET_TYPE (ftype));
 182       if (TYPE_CODE (ftype) == TYPE_CODE_FUNC
 183           || TYPE_CODE (ftype) == TYPE_CODE_METHOD)
 184         {
 185           funaddr = gdbarch_convert_from_func_ptr_addr (current_gdbarch,
 186                                                         funaddr,
 187                                                         &current_target);
 188           value_type = TYPE_TARGET_TYPE (ftype);
 189         }
 190       else
 191         value_type = builtin_type_int;
 192     }
 193   else if (code == TYPE_CODE_INT)
 194     {
 195       /* Handle the case of functions lacking debugging info.
 196          Their values are characters since their addresses are char */
 197       if (TYPE_LENGTH (ftype) == 1)
 198         funaddr = value_as_address (value_addr (function));
 199       else
 200         /* Handle integer used as address of a function.  */
 201         funaddr = (CORE_ADDR) value_as_long (function);
 202
 203       value_type = builtin_type_int;
 204     }
 205   else
 206     error ("Invalid data type for function to be called.");
 207
 208   *retval_type = value_type;
 209   return funaddr + FUNCTION_START_OFFSET;
 210 }
 211
 212 /* Call breakpoint_auto_delete on the current contents of the bpstat
 213    pointed to by arg (which is really a bpstat *).  */
 214
 215 static void
 216 breakpoint_auto_delete_contents (void *arg)
 217 {
 218   breakpoint_auto_delete (*(bpstat *) arg);
 219 }
 220
 221 static CORE_ADDR
 222 generic_push_dummy_code (struct gdbarch *gdbarch,
 223                          CORE_ADDR sp, CORE_ADDR funaddr, int using_gcc,
 224                          struct value **args, int nargs,
 225                          struct type *value_type,
 226                          CORE_ADDR *real_pc, CORE_ADDR *bp_addr)
 227 {
 228   /* Something here to findout the size of a breakpoint and then
 229      allocate space for it on the stack.  */
 230   int bplen;
 231   /* This code assumes frame align.  */
 232   gdb_assert (gdbarch_frame_align_p (gdbarch));
 233   /* Force the stack's alignment.  The intent is to ensure that the SP
 234      is aligned to at least a breakpoint instruction's boundary.  */
 235   sp = gdbarch_frame_align (gdbarch, sp);
 236   /* Allocate space for, and then position the breakpoint on the
 237      stack.  */
 238   if (gdbarch_inner_than (gdbarch, 1, 2))
 239     {
 240       CORE_ADDR bppc = sp;
 241       gdbarch_breakpoint_from_pc (gdbarch, &bppc, &bplen);
 242       sp = gdbarch_frame_align (gdbarch, sp - bplen);
 243       (*bp_addr) = sp;
 244       /* Should the breakpoint size/location be re-computed here?  */
 245     }
 246   else
 247     {
 248       (*bp_addr) = sp;
 249       gdbarch_breakpoint_from_pc (gdbarch, bp_addr, &bplen);
 250       sp = gdbarch_frame_align (gdbarch, sp + bplen);
 251     }
 252   /* Inferior resumes at the function entry point.  */
 253   (*real_pc) = funaddr;
 254   return sp;
 255 }
 256
 257 /* For CALL_DUMMY_ON_STACK, push a breakpoint sequence that the called
 258    function returns to.  */
 259
 260 static CORE_ADDR
 261 push_dummy_code (struct gdbarch *gdbarch,
 262                  CORE_ADDR sp, CORE_ADDR funaddr, int using_gcc,
 263                  struct value **args, int nargs,
 264                  struct type *value_type,
 265                  CORE_ADDR *real_pc, CORE_ADDR *bp_addr)
 266 {
 267   if (gdbarch_push_dummy_code_p (gdbarch))
 268     return gdbarch_push_dummy_code (gdbarch, sp, funaddr, using_gcc,
 269                                     args, nargs, value_type, real_pc, bp_addr);
 270   else
 271     return generic_push_dummy_code (gdbarch, sp, funaddr, using_gcc,
 272                                     args, nargs, value_type, real_pc, bp_addr);
 273 }
 274
 275 /* All this stuff with a dummy frame may seem unnecessarily complicated
 276    (why not just save registers in GDB?).  The purpose of pushing a dummy
 277    frame which looks just like a real frame is so that if you call a
 278    function and then hit a breakpoint (get a signal, etc), "backtrace"
 279    will look right.  Whether the backtrace needs to actually show the
 280    stack at the time the inferior function was called is debatable, but
 281    it certainly needs to not display garbage.  So if you are contemplating
 282    making dummy frames be different from normal frames, consider that.  */
 283
 284 /* Perform a function call in the inferior.
 285    ARGS is a vector of values of arguments (NARGS of them).
 286    FUNCTION is a value, the function to be called.
 287    Returns a value representing what the function returned.
 288    May fail to return, if a breakpoint or signal is hit
 289    during the execution of the function.
 290
 291    ARGS is modified to contain coerced values. */
 292
 293 struct value *
 294 call_function_by_hand (struct value *function, int nargs, struct value **args)
 295 {
 296   CORE_ADDR sp;
 297   CORE_ADDR dummy_addr;
 298   struct type *value_type;
 299   unsigned char struct_return;
 300   CORE_ADDR struct_addr = 0;
 301   struct regcache *retbuf;
 302   struct cleanup *retbuf_cleanup;
 303   struct inferior_status *inf_status;
 304   struct cleanup *inf_status_cleanup;
 305   CORE_ADDR funaddr;
 306   int using_gcc;                /* Set to version of gcc in use, or zero if not gcc */
 307   CORE_ADDR real_pc;
 308   struct type *ftype = check_typedef (SYMBOL_TYPE (function));
 309   CORE_ADDR bp_addr;
 310
 311   if (!target_has_execution)
 312     noprocess ();
 313
 314   /* Create a cleanup chain that contains the retbuf (buffer
 315      containing the register values).  This chain is create BEFORE the
 316      inf_status chain so that the inferior status can cleaned up
 317      (restored or discarded) without having the retbuf freed.  */
 318   retbuf = regcache_xmalloc (current_gdbarch);
 319   retbuf_cleanup = make_cleanup_regcache_xfree (retbuf);
 320
 321   /* A cleanup for the inferior status.  Create this AFTER the retbuf
 322      so that this can be discarded or applied without interfering with
 323      the regbuf.  */
 324   inf_status = save_inferior_status (1);
 325   inf_status_cleanup = make_cleanup_restore_inferior_status (inf_status);
 326
 327   if (DEPRECATED_PUSH_DUMMY_FRAME_P ())
 328     {
 329       /* DEPRECATED_PUSH_DUMMY_FRAME is responsible for saving the
 330          inferior registers (and frame_pop() for restoring them).  (At
 331          least on most machines) they are saved on the stack in the
 332          inferior.  */
 333       DEPRECATED_PUSH_DUMMY_FRAME;
 334     }
 335   else
 336     {
 337       /* FIXME: cagney/2003-02-26: Step zero of this little tinker is
 338       to extract the generic dummy frame code from the architecture
 339       vector.  Hence this direct call.
 340
 341       A follow-on change is to modify this interface so that it takes
 342       thread OR frame OR ptid as a parameter, and returns a dummy
 343       frame handle.  The handle can then be used further down as a
 344       parameter to generic_save_dummy_frame_tos().  Hmm, thinking
 345       about it, since everything is ment to be using generic dummy
 346       frames, why not even use some of the dummy frame code to here -
 347       do a regcache dup and then pass the duped regcache, along with
 348       all the other stuff, at one single point.
 349
 350       In fact, you can even save the structure's return address in the
 351       dummy frame and fix one of those nasty lost struct return edge
 352       conditions.  */
 353       generic_push_dummy_frame ();
 354     }
 355
 356   /* Ensure that the initial SP is correctly aligned.  */
 357   {
 358     CORE_ADDR old_sp = read_sp ();
 359     if (gdbarch_frame_align_p (current_gdbarch))
 360       {
 361         sp = gdbarch_frame_align (current_gdbarch, old_sp);
 362         /* NOTE: cagney/2003-08-13: Skip the "red zone".  For some
 363            ABIs, a function can use memory beyond the inner most stack
 364            address.  AMD64 called that region the "red zone".  Skip at
 365            least the "red zone" size before allocating any space on
 366            the stack.  */
 367         if (INNER_THAN (1, 2))
 368           sp -= gdbarch_frame_red_zone_size (current_gdbarch);
 369         else
 370           sp += gdbarch_frame_red_zone_size (current_gdbarch);
 371         /* Still aligned?  */
 372         gdb_assert (sp == gdbarch_frame_align (current_gdbarch, sp));
 373         /* NOTE: cagney/2002-09-18:
 374
 375            On a RISC architecture, a void parameterless generic dummy
 376            frame (i.e., no parameters, no result) typically does not
 377            need to push anything the stack and hence can leave SP and
 378            FP.  Similarly, a frameless (possibly leaf) function does
 379            not push anything on the stack and, hence, that too can
 380            leave FP and SP unchanged.  As a consequence, a sequence of
 381            void parameterless generic dummy frame calls to frameless
 382            functions will create a sequence of effectively identical
 383            frames (SP, FP and TOS and PC the same).  This, not
 384            suprisingly, results in what appears to be a stack in an
 385            infinite loop --- when GDB tries to find a generic dummy
 386            frame on the internal dummy frame stack, it will always
 387            find the first one.
 388
 389            To avoid this problem, the code below always grows the
 390            stack.  That way, two dummy frames can never be identical.
 391            It does burn a few bytes of stack but that is a small price
 392            to pay :-).  */
 393         if (sp == old_sp)
 394           {
 395             if (INNER_THAN (1, 2))
 396               /* Stack grows down.  */
 397               sp = gdbarch_frame_align (current_gdbarch, old_sp - 1);
 398             else
 399               /* Stack grows up.  */
 400               sp = gdbarch_frame_align (current_gdbarch, old_sp + 1);
 401           }
 402         gdb_assert ((INNER_THAN (1, 2) && sp <= old_sp)
 403                     || (INNER_THAN (2, 1) && sp >= old_sp));
 404       }
 405     else
 406       /* FIXME: cagney/2002-09-18: Hey, you loose!
 407
 408          Who knows how badly aligned the SP is!
 409
 410          If the generic dummy frame ends up empty (because nothing is
 411          pushed) GDB won't be able to correctly perform back traces.
 412          If a target is having trouble with backtraces, first thing to
 413          do is add FRAME_ALIGN() to the architecture vector. If that
 414          fails, try unwind_dummy_id().
 415
 416          If the ABI specifies a "Red Zone" (see the doco) the code
 417          below will quietly trash it.  */
 418       sp = old_sp;
 419   }
 420
 421   funaddr = find_function_addr (function, &value_type);
 422   CHECK_TYPEDEF (value_type);
 423
 424   {
 425     struct block *b = block_for_pc (funaddr);
 426     /* If compiled without -g, assume GCC 2.  */
 427     using_gcc = (b == NULL ? 2 : BLOCK_GCC_COMPILED (b));
 428   }
 429
 430   /* Are we returning a value using a structure return or a normal
 431      value return? */
 432
 433   struct_return = using_struct_return (value_type, using_gcc);
 434
 435   /* Determine the location of the breakpoint (and possibly other
 436      stuff) that the called function will return to.  The SPARC, for a
 437      function returning a structure or union, needs to make space for
 438      not just the breakpoint but also an extra word containing the
 439      size (?) of the structure being passed.  */
 440
 441   /* The actual breakpoint (at BP_ADDR) is inserted separatly so there
 442      is no need to write that out.  */
 443
 444   switch (CALL_DUMMY_LOCATION)
 445     {
 446     case ON_STACK:
 447       /* "dummy_addr" is here just to keep old targets happy.  New
 448          targets return that same information via "sp" and "bp_addr".  */
 449       if (INNER_THAN (1, 2))
 450         {
 451           sp = push_dummy_code (current_gdbarch, sp, funaddr,
 452                                 using_gcc, args, nargs, value_type,
 453                                 &real_pc, &bp_addr);
 454           dummy_addr = sp;
 455         }
 456       else
 457         {
 458           dummy_addr = sp;
 459           sp = push_dummy_code (current_gdbarch, sp, funaddr,
 460                                 using_gcc, args, nargs, value_type,
 461                                 &real_pc, &bp_addr);
 462         }
 463       break;
 464     case AT_ENTRY_POINT:
 465       if (DEPRECATED_FIX_CALL_DUMMY_P ()
 466           && !gdbarch_push_dummy_call_p (current_gdbarch))
 467         {
 468           /* Sigh.  Some targets use DEPRECATED_FIX_CALL_DUMMY to
 469              shove extra stuff onto the stack or into registers.  That
 470              code should be in PUSH_DUMMY_CALL, however, in the mean
 471              time ...  */
 472           /* If the target is manipulating DUMMY1, it looses big time.  */
 473           void *dummy1 = NULL;
 474           DEPRECATED_FIX_CALL_DUMMY (dummy1, sp, funaddr, nargs, args,
 475                                      value_type, using_gcc);
 476         }
 477       real_pc = funaddr;
 478       dummy_addr = entry_point_address ();
 479       /* Make certain that the address points at real code, and not a
 480          function descriptor.  */
 481       dummy_addr = gdbarch_convert_from_func_ptr_addr (current_gdbarch,
 482                                                        dummy_addr,
 483                                                        &current_target);
 484       /* A call dummy always consists of just a single breakpoint, so
 485          it's address is the same as the address of the dummy.  */
 486       bp_addr = dummy_addr;
 487       break;
 488     case AT_SYMBOL:
 489       /* Some executables define a symbol __CALL_DUMMY_ADDRESS whose
 490          address is the location where the breakpoint should be
 491          placed.  Once all targets are using the overhauled frame code
 492          this can be deleted - ON_STACK is a better option.  */
 493       {
 494         struct minimal_symbol *sym;
 495
 496         sym = lookup_minimal_symbol ("__CALL_DUMMY_ADDRESS", NULL, NULL);
 497         real_pc = funaddr;
 498         if (sym)
 499           dummy_addr = SYMBOL_VALUE_ADDRESS (sym);
 500         else
 501           dummy_addr = entry_point_address ();
 502         /* Make certain that the address points at real code, and not
 503            a function descriptor.  */
 504         dummy_addr = gdbarch_convert_from_func_ptr_addr (current_gdbarch,
 505                                                          dummy_addr,
 506                                                          &current_target);
 507         /* A call dummy always consists of just a single breakpoint,
 508            so it's address is the same as the address of the dummy.  */
 509         bp_addr = dummy_addr;
 510         break;
 511       }
 512     default:
 513       internal_error (__FILE__, __LINE__, "bad switch");
 514     }
 515
 516   /* Save where the breakpoint is going to be inserted so that the
 517      dummy-frame code is later able to re-identify it.  */
 518   generic_save_call_dummy_addr (bp_addr, bp_addr + 1);
 519
 520   if (nargs < TYPE_NFIELDS (ftype))
 521     error ("too few arguments in function call");
 522
 523   {
 524     int i;
 525     for (i = nargs - 1; i >= 0; i--)
 526       {
 527         int prototyped;
 528         struct type *param_type;
 529
 530         /* FIXME drow/2002-05-31: Should just always mark methods as
 531            prototyped.  Can we respect TYPE_VARARGS?  Probably not.  */
 532         if (TYPE_CODE (ftype) == TYPE_CODE_METHOD)
 533           prototyped = 1;
 534         else if (i < TYPE_NFIELDS (ftype))
 535           prototyped = TYPE_PROTOTYPED (ftype);
 536         else
 537           prototyped = 0;
 538
 539         if (i < TYPE_NFIELDS (ftype))
 540           param_type = TYPE_FIELD_TYPE (ftype, i);
 541         else
 542           param_type = NULL;
 543
 544         args[i] = value_arg_coerce (args[i], param_type, prototyped);
 545
 546         /* elz: this code is to handle the case in which the function
 547            to be called has a pointer to function as parameter and the
 548            corresponding actual argument is the address of a function
 549            and not a pointer to function variable.  In aCC compiled
 550            code, the calls through pointers to functions (in the body
 551            of the function called by hand) are made via
 552            $$dyncall_external which requires some registers setting,
 553            this is taken care of if we call via a function pointer
 554            variable, but not via a function address.  In cc this is
 555            not a problem. */
 556
 557         if (using_gcc == 0)
 558           {
 559             if (param_type != NULL && TYPE_CODE (ftype) != TYPE_CODE_METHOD)
 560               {
 561                 /* if this parameter is a pointer to function.  */
 562                 if (TYPE_CODE (param_type) == TYPE_CODE_PTR)
 563                   if (TYPE_CODE (TYPE_TARGET_TYPE (param_type)) == TYPE_CODE_FUNC)
 564                     /* elz: FIXME here should go the test about the
 565                        compiler used to compile the target. We want to
 566                        issue the error message only if the compiler
 567                        used was HP's aCC.  If we used HP's cc, then
 568                        there is no problem and no need to return at
 569                        this point.  */
 570                     /* Go see if the actual parameter is a variable of
 571                        type pointer to function or just a function.  */
 572                     if (args[i]->lval == not_lval)
 573                       {
 574                         char *arg_name;
 575                         if (find_pc_partial_function ((CORE_ADDR) args[i]->aligner.contents[0], &arg_name, NULL, NULL))
 576                           error ("\
 577 You cannot use function <%s> as argument. \n\
 578 You must use a pointer to function type variable. Command ignored.", arg_name);
 579                       }
 580               }
 581           }
 582       }
 583   }
 584
 585   if (DEPRECATED_REG_STRUCT_HAS_ADDR_P ())
 586     {
 587       int i;
 588       /* This is a machine like the sparc, where we may need to pass a
 589          pointer to the structure, not the structure itself.  */
 590       for (i = nargs - 1; i >= 0; i--)
 591         {
 592           struct type *arg_type = check_typedef (VALUE_TYPE (args[i]));
 593           if ((TYPE_CODE (arg_type) == TYPE_CODE_STRUCT
 594                || TYPE_CODE (arg_type) == TYPE_CODE_UNION
 595                || TYPE_CODE (arg_type) == TYPE_CODE_ARRAY
 596                || TYPE_CODE (arg_type) == TYPE_CODE_STRING
 597                || TYPE_CODE (arg_type) == TYPE_CODE_BITSTRING
 598                || TYPE_CODE (arg_type) == TYPE_CODE_SET
 599                || (TYPE_CODE (arg_type) == TYPE_CODE_FLT
 600                    && TYPE_LENGTH (arg_type) > 8)
 601                )
 602               && DEPRECATED_REG_STRUCT_HAS_ADDR (using_gcc, arg_type))
 603             {
 604               CORE_ADDR addr;
 605               int len;          /*  = TYPE_LENGTH (arg_type); */
 606               int aligned_len;
 607               arg_type = check_typedef (VALUE_ENCLOSING_TYPE (args[i]));
 608               len = TYPE_LENGTH (arg_type);
 609
 610               if (DEPRECATED_STACK_ALIGN_P ())
 611                 /* MVS 11/22/96: I think at least some of this
 612                    stack_align code is really broken.  Better to let
 613                    PUSH_ARGUMENTS adjust the stack in a target-defined
 614                    manner.  */
 615                 aligned_len = DEPRECATED_STACK_ALIGN (len);
 616               else
 617                 aligned_len = len;
 618               if (INNER_THAN (1, 2))
 619                 {
 620                   /* stack grows downward */
 621                   sp -= aligned_len;
 622                   /* ... so the address of the thing we push is the
 623                      stack pointer after we push it.  */
 624                   addr = sp;
 625                 }
 626               else
 627                 {
 628                   /* The stack grows up, so the address of the thing
 629                      we push is the stack pointer before we push it.  */
 630                   addr = sp;
 631                   sp += aligned_len;
 632                 }
 633               /* Push the structure.  */
 634               write_memory (addr, VALUE_CONTENTS_ALL (args[i]), len);
 635               /* The value we're going to pass is the address of the
 636                  thing we just pushed.  */
 637               /*args[i] = value_from_longest (lookup_pointer_type (value_type),
 638                 (LONGEST) addr); */
 639               args[i] = value_from_pointer (lookup_pointer_type (arg_type),
 640                                             addr);
 641             }
 642         }
 643     }
 644
 645
 646   /* Reserve space for the return structure to be written on the
 647      stack, if necessary.  Make certain that the value is correctly
 648      aligned. */
 649
 650   if (struct_return)
 651     {
 652       int len = TYPE_LENGTH (value_type);
 653       if (DEPRECATED_STACK_ALIGN_P ())
 654         /* NOTE: cagney/2003-03-22: Should rely on frame align, rather
 655            than stack align to force the alignment of the stack.  */
 656         len = DEPRECATED_STACK_ALIGN (len);
 657       if (INNER_THAN (1, 2))
 658         {
 659           /* Stack grows downward.  Align STRUCT_ADDR and SP after
 660              making space for the return value.  */
 661           sp -= len;
 662           if (gdbarch_frame_align_p (current_gdbarch))
 663             sp = gdbarch_frame_align (current_gdbarch, sp);
 664           struct_addr = sp;
 665         }
 666       else
 667         {
 668           /* Stack grows upward.  Align the frame, allocate space, and
 669              then again, re-align the frame??? */
 670           if (gdbarch_frame_align_p (current_gdbarch))
 671             sp = gdbarch_frame_align (current_gdbarch, sp);
 672           struct_addr = sp;
 673           sp += len;
 674           if (gdbarch_frame_align_p (current_gdbarch))
 675             sp = gdbarch_frame_align (current_gdbarch, sp);
 676         }
 677     }
 678
 679   /* Create the dummy stack frame.  Pass in the call dummy address as,
 680      presumably, the ABI code knows where, in the call dummy, the
 681      return address should be pointed.  */
 682   if (gdbarch_push_dummy_call_p (current_gdbarch))
 683     /* When there is no push_dummy_call method, should this code
 684        simply error out.  That would the implementation of this method
 685        for all ABIs (which is probably a good thing).  */
 686     sp = gdbarch_push_dummy_call (current_gdbarch, funaddr, current_regcache,
 687                                   bp_addr, nargs, args, sp, struct_return,
 688                                   struct_addr);
 689   else  if (DEPRECATED_PUSH_ARGUMENTS_P ())
 690     /* Keep old targets working.  */
 691     sp = DEPRECATED_PUSH_ARGUMENTS (nargs, args, sp, struct_return,
 692                                     struct_addr);
 693   else
 694     sp = legacy_push_arguments (nargs, args, sp, struct_return, struct_addr);
 695
 696   if (DEPRECATED_PUSH_RETURN_ADDRESS_P ())
 697     /* for targets that use no CALL_DUMMY */
 698     /* There are a number of targets now which actually don't write
 699        any CALL_DUMMY instructions into the target, but instead just
 700        save the machine state, push the arguments, and jump directly
 701        to the callee function.  Since this doesn't actually involve
 702        executing a JSR/BSR instruction, the return address must be set
 703        up by hand, either by pushing onto the stack or copying into a
 704        return-address register as appropriate.  Formerly this has been
 705        done in PUSH_ARGUMENTS, but that's overloading its
 706        functionality a bit, so I'm making it explicit to do it here.  */
 707     /* NOTE: cagney/2003-04-22: The first parameter ("real_pc") has
 708        been replaced with zero, it turns out that no implementation
 709        used that parameter.  This occured because the value being
 710        supplied - the address of the called function's entry point
 711        instead of the address of the breakpoint that the called
 712        function should return to - wasn't useful.  */
 713     sp = DEPRECATED_PUSH_RETURN_ADDRESS (0, sp);
 714
 715   /* NOTE: cagney/2003-03-23: Diable this code when there is a
 716      push_dummy_call() method.  Since that method will have already
 717      handled any alignment issues, the code below is entirely
 718      redundant.  */
 719   if (!gdbarch_push_dummy_call_p (current_gdbarch)
 720       && DEPRECATED_STACK_ALIGN_P () && !INNER_THAN (1, 2))
 721     {
 722       /* If stack grows up, we must leave a hole at the bottom, note
 723          that sp already has been advanced for the arguments!  */
 724       sp = DEPRECATED_STACK_ALIGN (sp);
 725     }
 726
 727   /* Store the address at which the structure is supposed to be
 728      written.  */
 729   /* NOTE: 2003-03-24: Since PUSH_ARGUMENTS can (and typically does)
 730      store the struct return address, this call is entirely redundant.  */
 731   if (struct_return && DEPRECATED_STORE_STRUCT_RETURN_P ())
 732     DEPRECATED_STORE_STRUCT_RETURN (struct_addr, sp);
 733
 734   /* Write the stack pointer.  This is here because the statements
 735      above might fool with it.  On SPARC, this write also stores the
 736      register window into the right place in the new stack frame,
 737      which otherwise wouldn't happen (see store_inferior_registers in
 738      sparc-nat.c).  */
 739   /* NOTE: cagney/2003-03-23: Since the architecture method
 740      push_dummy_call() should have already stored the stack pointer
 741      (as part of creating the fake call frame), and none of the code
 742      following that call adjusts the stack-pointer value, the below
 743      call is entirely redundant.  */
 744   if (DEPRECATED_DUMMY_WRITE_SP_P ())
 745     DEPRECATED_DUMMY_WRITE_SP (sp);
 746
 747   if (gdbarch_unwind_dummy_id_p (current_gdbarch))
 748     {
 749       /* Sanity.  The exact same SP value is returned by
 750          PUSH_DUMMY_CALL, saved as the dummy-frame TOS, and used by
 751          unwind_dummy_id to form the frame ID's stack address.  */
 752       generic_save_dummy_frame_tos (sp);
 753     }
 754   else if (DEPRECATED_SAVE_DUMMY_FRAME_TOS_P ())
 755     DEPRECATED_SAVE_DUMMY_FRAME_TOS (sp);
 756
 757   /* Now proceed, having reached the desired place.  */
 758   clear_proceed_status ();
 759
 760   /* Create a momentary breakpoint at the return address of the
 761      inferior.  That way it breaks when it returns.  */
 762
 763   {
 764     struct breakpoint *bpt;
 765     struct symtab_and_line sal;
 766     struct frame_id frame;
 767     init_sal (&sal);            /* initialize to zeroes */
 768     sal.pc = bp_addr;
 769     sal.section = find_pc_overlay (sal.pc);
 770     /* Set up a frame ID for the dummy frame so we can pass it to
 771        set_momentary_breakpoint.  We need to give the breakpoint a
 772        frame ID so that the breakpoint code can correctly re-identify
 773        the dummy breakpoint.  */
 774     if (gdbarch_unwind_dummy_id_p (current_gdbarch))
 775       {
 776         /* Sanity.  The exact same SP value is returned by
 777          PUSH_DUMMY_CALL, saved as the dummy-frame TOS, and used by
 778          unwind_dummy_id to form the frame ID's stack address.  */
 779         frame = frame_id_build (sp, sal.pc);
 780       }
 781     else
 782       {
 783         /* The assumption here is that push_dummy_call() returned the
 784            stack part of the frame ID.  Unfortunately, many older
 785            architectures were, via a convoluted mess, relying on the
 786            poorly defined and greatly overloaded
 787            DEPRECATED_TARGET_READ_FP or DEPRECATED_FP_REGNUM to supply
 788            the value.  */
 789         if (DEPRECATED_TARGET_READ_FP_P ())
 790           frame = frame_id_build (DEPRECATED_TARGET_READ_FP (), sal.pc);
 791         else if (DEPRECATED_FP_REGNUM >= 0)
 792           frame = frame_id_build (read_register (DEPRECATED_FP_REGNUM), sal.pc);
 793         else
 794           frame = frame_id_build (sp, sal.pc);
 795       }
 796     bpt = set_momentary_breakpoint (sal, frame, bp_call_dummy);
 797     bpt->disposition = disp_del;
 798   }
 799
 800   /* Execute a "stack dummy", a piece of code stored in the stack by
 801      the debugger to be executed in the inferior.
 802
 803      The dummy's frame is automatically popped whenever that break is
 804      hit.  If that is the first time the program stops,
 805      call_function_by_hand returns to its caller with that frame
 806      already gone and sets RC to 0.
 807
 808      Otherwise, set RC to a non-zero value.  If the called function
 809      receives a random signal, we do not allow the user to continue
 810      executing it as this may not work.  The dummy frame is poped and
 811      we return 1.  If we hit a breakpoint, we leave the frame in place
 812      and return 2 (the frame will eventually be popped when we do hit
 813      the dummy end breakpoint).  */
 814
 815   {
 816     struct cleanup *old_cleanups = make_cleanup (null_cleanup, 0);
 817     int saved_async = 0;
 818
 819     /* If all error()s out of proceed ended up calling normal_stop
 820        (and perhaps they should; it already does in the special case
 821        of error out of resume()), then we wouldn't need this.  */
 822     make_cleanup (breakpoint_auto_delete_contents, &stop_bpstat);
 823
 824     disable_watchpoints_before_interactive_call_start ();
 825     proceed_to_finish = 1;      /* We want stop_registers, please... */
 826
 827     if (target_can_async_p ())
 828       saved_async = target_async_mask (0);
 829
 830     proceed (real_pc, TARGET_SIGNAL_0, 0);
 831
 832     if (saved_async)
 833       target_async_mask (saved_async);
 834
 835     enable_watchpoints_after_interactive_call_stop ();
 836
 837     discard_cleanups (old_cleanups);
 838   }
 839
 840   if (stopped_by_random_signal || !stop_stack_dummy)
 841     {
 842       /* Find the name of the function we're about to complain about.  */
 843       const char *name = NULL;
 844       {
 845         struct symbol *symbol = find_pc_function (funaddr);
 846         if (symbol)
 847           name = SYMBOL_PRINT_NAME (symbol);
 848         else
 849           {
 850             /* Try the minimal symbols.  */
 851             struct minimal_symbol *msymbol = lookup_minimal_symbol_by_pc (funaddr);
 852             if (msymbol)
 853               name = SYMBOL_PRINT_NAME (msymbol);
 854           }
 855         if (name == NULL)
 856           {
 857             /* Can't use a cleanup here.  It is discarded, instead use
 858                an alloca.  */
 859             char *tmp = xstrprintf ("at %s", local_hex_string (funaddr));
 860             char *a = alloca (strlen (tmp) + 1);
 861             strcpy (a, tmp);
 862             xfree (tmp);
 863             name = a;
 864           }
 865       }
 866       if (stopped_by_random_signal)
 867         {
 868           /* We stopped inside the FUNCTION because of a random
 869              signal.  Further execution of the FUNCTION is not
 870              allowed. */
 871
 872           if (unwind_on_signal_p)
 873             {
 874               /* The user wants the context restored. */
 875
 876               /* We must get back to the frame we were before the
 877                  dummy call. */
 878               frame_pop (get_current_frame ());
 879
 880               /* FIXME: Insert a bunch of wrap_here; name can be very
 881                  long if it's a C++ name with arguments and stuff.  */
 882               error ("\
 883 The program being debugged was signaled while in a function called from GDB.\n\
 884 GDB has restored the context to what it was before the call.\n\
 885 To change this behavior use \"set unwindonsignal off\"\n\
 886 Evaluation of the expression containing the function (%s) will be abandoned.",
 887                      name);
 888             }
 889           else
 890             {
 891               /* The user wants to stay in the frame where we stopped
 892                  (default).*/
 893               /* If we restored the inferior status (via the cleanup),
 894                  we would print a spurious error message (Unable to
 895                  restore previously selected frame), would write the
 896                  registers from the inf_status (which is wrong), and
 897                  would do other wrong things.  */
 898               discard_cleanups (inf_status_cleanup);
 899               discard_inferior_status (inf_status);
 900               /* FIXME: Insert a bunch of wrap_here; name can be very
 901                  long if it's a C++ name with arguments and stuff.  */
 902               error ("\
 903 The program being debugged was signaled while in a function called from GDB.\n\
 904 GDB remains in the frame where the signal was received.\n\
 905 To change this behavior use \"set unwindonsignal on\"\n\
 906 Evaluation of the expression containing the function (%s) will be abandoned.",
 907                      name);
 908             }
 909         }
 910
 911       if (!stop_stack_dummy)
 912         {
 913           /* We hit a breakpoint inside the FUNCTION. */
 914           /* If we restored the inferior status (via the cleanup), we
 915              would print a spurious error message (Unable to restore
 916              previously selected frame), would write the registers
 917              from the inf_status (which is wrong), and would do other
 918              wrong things.  */
 919           discard_cleanups (inf_status_cleanup);
 920           discard_inferior_status (inf_status);
 921           /* The following error message used to say "The expression
 922              which contained the function call has been discarded."
 923              It is a hard concept to explain in a few words.  Ideally,
 924              GDB would be able to resume evaluation of the expression
 925              when the function finally is done executing.  Perhaps
 926              someday this will be implemented (it would not be easy).  */
 927           /* FIXME: Insert a bunch of wrap_here; name can be very long if it's
 928              a C++ name with arguments and stuff.  */
 929           error ("\
 930 The program being debugged stopped while in a function called from GDB.\n\
 931 When the function (%s) is done executing, GDB will silently\n\
 932 stop (instead of continuing to evaluate the expression containing\n\
 933 the function call).", name);
 934         }
 935
 936       /* The above code errors out, so ...  */
 937       internal_error (__FILE__, __LINE__, "... should not be here");
 938     }
 939
 940   /* If we get here the called FUNCTION run to completion. */
 941
 942   /* On normal return, the stack dummy has been popped already.  */
 943   regcache_cpy_no_passthrough (retbuf, stop_registers);
 944
 945   /* Restore the inferior status, via its cleanup.  At this stage,
 946      leave the RETBUF alone.  */
 947   do_cleanups (inf_status_cleanup);
 948
 949   /* Figure out the value returned by the function.  */
 950   if (struct_return)
 951     {
 952       /* NOTE: cagney/2003-09-27: This assumes that PUSH_DUMMY_CALL
 953          has correctly stored STRUCT_ADDR in the target.  In the past
 954          that hasn't been the case, the old MIPS PUSH_ARGUMENTS
 955          (PUSH_DUMMY_CALL precursor) would silently move the location
 956          of the struct return value making STRUCT_ADDR bogus.  If
 957          you're seeing problems with values being returned using the
 958          "struct return convention", check that PUSH_DUMMY_CALL isn't
 959          playing tricks.  */
 960       struct value *retval = value_at (value_type, struct_addr, NULL);
 961       do_cleanups (retbuf_cleanup);
 962       return retval;
 963     }
 964   else
 965     {
 966       /* The non-register case was handled above.  */
 967       struct value *retval = register_value_being_returned (value_type,
 968                                                             retbuf);
 969       do_cleanups (retbuf_cleanup);
 970       return retval;
 971     }
 972 }
 973
 974 void _initialize_infcall (void);
 975
 976 void
 977 _initialize_infcall (void)
 978 {
 979   add_setshow_boolean_cmd ("coerce-float-to-double", class_obscure,
 980                            &coerce_float_to_double_p, "\
 981 Set coercion of floats to doubles when calling functions\n\
 982 Variables of type float should generally be converted to doubles before\n\
 983 calling an unprototyped function, and left alone when calling a prototyped\n\
 984 function.  However, some older debug info formats do not provide enough\n\
 985 information to determine that a function is prototyped.  If this flag is\n\
 986 set, GDB will perform the conversion for a function it considers\n\
 987 unprototyped.\n\
 988 The default is to perform the conversion.\n", "\
 989 Show coercion of floats to doubles when calling functions\n\
 990 Variables of type float should generally be converted to doubles before\n\
 991 calling an unprototyped function, and left alone when calling a prototyped\n\
 992 function.  However, some older debug info formats do not provide enough\n\
 993 information to determine that a function is prototyped.  If this flag is\n\
 994 set, GDB will perform the conversion for a function it considers\n\
 995 unprototyped.\n\
 996 The default is to perform the conversion.\n",
 997                            NULL, NULL, &setlist, &showlist);
 998
 999   add_setshow_boolean_cmd ("unwindonsignal", no_class,
1000                            &unwind_on_signal_p, "\
1001 Set unwinding of stack if a signal is received while in a call dummy.\n\
1002 The unwindonsignal lets the user determine what gdb should do if a signal\n\
1003 is received while in a function called from gdb (call dummy).  If set, gdb\n\
1004 unwinds the stack and restore the context to what as it was before the call.\n\
1005 The default is to stop in the frame where the signal was received.", "\
1006 Show unwinding of stack if a signal is received while in a call dummy.\n\
1007 The unwindonsignal lets the user determine what gdb should do if a signal\n\
1008 is received while in a function called from gdb (call dummy).  If set, gdb\n\
1009 unwinds the stack and restore the context to what as it was before the call.\n\
1010 The default is to stop in the frame where the signal was received.",
1011                            NULL, NULL, &setlist, &showlist);
1012 }