2003-06-08 Andrew Cagney <cagney@redhat.com>

[thirdparty/binutils-gdb.git] / gdb / infcall.c

/* Perform an inferior function call, for GDB, the GNU debugger.

   Copyright 1986, 1987, 1988, 1989, 1990, 1991, 1992, 1993, 1994,
   1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003 Free Software
   Foundation, Inc.

   This file is part of GDB.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 2 of the License, or
   (at your option) any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 59 Temple Place - Suite 330,
   Boston, MA 02111-1307, USA.  */

#include "defs.h"
#include "breakpoint.h"
#include "target.h"
#include "regcache.h"
#include "inferior.h"
#include "gdb_assert.h"
#include "block.h"
#include "gdbcore.h"
#include "language.h"
#include "symfile.h"
#include "gdbcmd.h"
#include "command.h"
#include "gdb_string.h"
#include "infcall.h"

/* NOTE: cagney/2003-04-16: What's the future of this code?

   GDB needs an asynchronous expression evaluator, that means an
   asynchronous inferior function call implementation, and that in
   turn means restructuring the code so that it is event driven.  */

/* How you should pass arguments to a function depends on whether it
   was defined in K&R style or prototype style.  If you define a
   function using the K&R syntax that takes a `float' argument, then
   callers must pass that argument as a `double'.  If you define the
   function using the prototype syntax, then you must pass the
   argument as a `float', with no promotion.

   Unfortunately, on certain older platforms, the debug info doesn't
   indicate reliably how each function was defined.  A function type's
   TYPE_FLAG_PROTOTYPED flag may be clear, even if the function was
   defined in prototype style.  When calling a function whose
   TYPE_FLAG_PROTOTYPED flag is clear, GDB consults this flag to
   decide what to do.

   For modern targets, it is proper to assume that, if the prototype
   flag is clear, that can be trusted: `float' arguments should be
   promoted to `double'.  For some older targets, if the prototype
   flag is clear, that doesn't tell us anything.  The default is to
   trust the debug information; the user can override this behavior
   with "set coerce-float-to-double 0".  */

static int coerce_float_to_double_p = 1;

/* This boolean tells what gdb should do if a signal is received while
   in a function called from gdb (call dummy).  If set, gdb unwinds
   the stack and restore the context to what as it was before the
   call.

   The default is to stop in the frame where the signal was received. */

int unwind_on_signal_p = 0;

/* Perform the standard coercions that are specified
   for arguments to be passed to C functions.

   If PARAM_TYPE is non-NULL, it is the expected parameter type.
   IS_PROTOTYPED is non-zero if the function declaration is prototyped.  */

static struct value *
value_arg_coerce (struct value *arg, struct type *param_type,
                  int is_prototyped)
{
  register struct type *arg_type = check_typedef (VALUE_TYPE (arg));
  register struct type *type
    = param_type ? check_typedef (param_type) : arg_type;

  switch (TYPE_CODE (type))
    {
    case TYPE_CODE_REF:
      if (TYPE_CODE (arg_type) != TYPE_CODE_REF
          && TYPE_CODE (arg_type) != TYPE_CODE_PTR)
        {
          arg = value_addr (arg);
          VALUE_TYPE (arg) = param_type;
          return arg;
        }
      break;
    case TYPE_CODE_INT:
    case TYPE_CODE_CHAR:
    case TYPE_CODE_BOOL:
    case TYPE_CODE_ENUM:
      /* If we don't have a prototype, coerce to integer type if necessary.  */
      if (!is_prototyped)
        {
          if (TYPE_LENGTH (type) < TYPE_LENGTH (builtin_type_int))
            type = builtin_type_int;
        }
      /* Currently all target ABIs require at least the width of an integer
         type for an argument.  We may have to conditionalize the following
         type coercion for future targets.  */
      if (TYPE_LENGTH (type) < TYPE_LENGTH (builtin_type_int))
        type = builtin_type_int;
      break;
    case TYPE_CODE_FLT:
      if (!is_prototyped && coerce_float_to_double_p)
        {
          if (TYPE_LENGTH (type) < TYPE_LENGTH (builtin_type_double))
            type = builtin_type_double;
          else if (TYPE_LENGTH (type) > TYPE_LENGTH (builtin_type_double))
            type = builtin_type_long_double;
        }
      break;
    case TYPE_CODE_FUNC:
      type = lookup_pointer_type (type);
      break;
    case TYPE_CODE_ARRAY:
      /* Arrays are coerced to pointers to their first element, unless
         they are vectors, in which case we want to leave them alone,
         because they are passed by value.  */
      if (current_language->c_style_arrays)
        if (!TYPE_VECTOR (type))
          type = lookup_pointer_type (TYPE_TARGET_TYPE (type));
      break;
    case TYPE_CODE_UNDEF:
    case TYPE_CODE_PTR:
    case TYPE_CODE_STRUCT:
    case TYPE_CODE_UNION:
    case TYPE_CODE_VOID:
    case TYPE_CODE_SET:
    case TYPE_CODE_RANGE:
    case TYPE_CODE_STRING:
    case TYPE_CODE_BITSTRING:
    case TYPE_CODE_ERROR:
    case TYPE_CODE_MEMBER:
    case TYPE_CODE_METHOD:
    case TYPE_CODE_COMPLEX:
    default:
      break;
    }

  return value_cast (type, arg);
}

/* Determine a function's address and its return type from its value.
   Calls error() if the function is not valid for calling.  */

CORE_ADDR
find_function_addr (struct value *function, struct type **retval_type)
{
  register struct type *ftype = check_typedef (VALUE_TYPE (function));
  register enum type_code code = TYPE_CODE (ftype);
  struct type *value_type;
  CORE_ADDR funaddr;

  /* If it's a member function, just look at the function
     part of it.  */

  /* Determine address to call.  */
  if (code == TYPE_CODE_FUNC || code == TYPE_CODE_METHOD)
    {
      funaddr = VALUE_ADDRESS (function);
      value_type = TYPE_TARGET_TYPE (ftype);
    }
  else if (code == TYPE_CODE_PTR)
    {
      funaddr = value_as_address (function);
      ftype = check_typedef (TYPE_TARGET_TYPE (ftype));
      if (TYPE_CODE (ftype) == TYPE_CODE_FUNC
          || TYPE_CODE (ftype) == TYPE_CODE_METHOD)
        {
          funaddr = CONVERT_FROM_FUNC_PTR_ADDR (funaddr);
          value_type = TYPE_TARGET_TYPE (ftype);
        }
      else
        value_type = builtin_type_int;
    }
  else if (code == TYPE_CODE_INT)
    {
      /* Handle the case of functions lacking debugging info.
         Their values are characters since their addresses are char */
      if (TYPE_LENGTH (ftype) == 1)
        funaddr = value_as_address (value_addr (function));
      else
        /* Handle integer used as address of a function.  */
        funaddr = (CORE_ADDR) value_as_long (function);

      value_type = builtin_type_int;
    }
  else
    error ("Invalid data type for function to be called.");

  *retval_type = value_type;
  return funaddr;
}

/* Call breakpoint_auto_delete on the current contents of the bpstat
   pointed to by arg (which is really a bpstat *).  */

static void
breakpoint_auto_delete_contents (void *arg)
{
  breakpoint_auto_delete (*(bpstat *) arg);
}

static CORE_ADDR
legacy_push_dummy_code (struct gdbarch *gdbarch,
                        CORE_ADDR sp, CORE_ADDR funaddr, int using_gcc,
                        struct value **args, int nargs,
                        struct type *value_type,
                        CORE_ADDR *real_pc, CORE_ADDR *bp_addr)
{
  /* CALL_DUMMY is an array of words (DEPRECATED_REGISTER_SIZE), but
     each word is in host byte order.  Before calling
     DEPRECATED_FIX_CALL_DUMMY, we byteswap it and remove any extra
     bytes which might exist because ULONGEST is bigger than
     DEPRECATED_REGISTER_SIZE.  */
  /* NOTE: This is pretty wierd, as the call dummy is actually a
     sequence of instructions.  But CISC machines will have to pack
     the instructions into DEPRECATED_REGISTER_SIZE units (and so will
     RISC machines for which INSTRUCTION_SIZE is not
     DEPRECATED_REGISTER_SIZE).  */
  /* NOTE: This is pretty stupid.  CALL_DUMMY should be in strict
     target byte order. */
  CORE_ADDR start_sp;
  ULONGEST *dummy = alloca (DEPRECATED_SIZEOF_CALL_DUMMY_WORDS);
  int sizeof_dummy1 = (DEPRECATED_REGISTER_SIZE
                       * DEPRECATED_SIZEOF_CALL_DUMMY_WORDS
                       / sizeof (ULONGEST));
  char *dummy1 = alloca (sizeof_dummy1);
  memcpy (dummy, DEPRECATED_CALL_DUMMY_WORDS,
          DEPRECATED_SIZEOF_CALL_DUMMY_WORDS);
  if (INNER_THAN (1, 2))
    {
      /* Stack grows down */
      sp -= sizeof_dummy1;
      start_sp = sp;
    }
  else
    {
      /* Stack grows up */
      start_sp = sp;
      sp += sizeof_dummy1;
    }
  /* NOTE: cagney/2002-09-10: Don't bother re-adjusting the stack
     after allocating space for the call dummy.  A target can specify
     a SIZEOF_DUMMY1 (via DEPRECATED_SIZEOF_CALL_DUMMY_WORDS) such
     that all local alignment requirements are met.  */
  /* Create a call sequence customized for this function and the
     number of arguments for it.  */
  {
    int i;
    for (i = 0; i < (int) (DEPRECATED_SIZEOF_CALL_DUMMY_WORDS / sizeof (dummy[0]));
         i++)
      store_unsigned_integer (&dummy1[i * DEPRECATED_REGISTER_SIZE],
                              DEPRECATED_REGISTER_SIZE,
                              (ULONGEST) dummy[i]);
  }
  /* NOTE: cagney/2003-04-22: This computation of REAL_PC, BP_ADDR and
     DUMMY_ADDR is pretty messed up.  It comes from constant tinkering
     with the values.  Instead a DEPRECATED_FIX_CALL_DUMMY replacement
     (PUSH_DUMMY_BREAKPOINT?) should just do everything.  */
#ifdef GDB_TARGET_IS_HPPA
  real_pc = DEPRECATED_FIX_CALL_DUMMY (dummy1, start_sp, funaddr, nargs, args,
                                       value_type, using_gcc);
#else
  if (DEPRECATED_FIX_CALL_DUMMY_P ())
    {
      /* gdb_assert (CALL_DUMMY_LOCATION == ON_STACK) true?  */
      DEPRECATED_FIX_CALL_DUMMY (dummy1, start_sp, funaddr, nargs, args,
                                 value_type, using_gcc);
    }
  (*real_pc) = start_sp;
#endif
  /* Yes, the offset is applied to the real_pc and not the dummy addr.
     Ulgh!  Blame the HP/UX target.  */
  (*bp_addr) = (*real_pc) + DEPRECATED_CALL_DUMMY_BREAKPOINT_OFFSET;
  /* Yes, the offset is applied to the real_pc and not the
     dummy_addr.  Ulgh!  Blame the HP/UX target.  */
  (*real_pc) += DEPRECATED_CALL_DUMMY_START_OFFSET;
  write_memory (start_sp, (char *) dummy1, sizeof_dummy1);
  if (DEPRECATED_USE_GENERIC_DUMMY_FRAMES)
    generic_save_call_dummy_addr (start_sp, start_sp + sizeof_dummy1);
  return sp;
}

static CORE_ADDR
generic_push_dummy_code (struct gdbarch *gdbarch,
                         CORE_ADDR sp, CORE_ADDR funaddr, int using_gcc,
                         struct value **args, int nargs,
                         struct type *value_type,
                         CORE_ADDR *real_pc, CORE_ADDR *bp_addr)
{
  /* Something here to findout the size of a breakpoint and then
     allocate space for it on the stack.  */
  int bplen;
  /* This code assumes frame align.  */
  gdb_assert (gdbarch_frame_align_p (gdbarch));
  /* Force the stack's alignment.  The intent is to ensure that the SP
     is aligned to at least a breakpoint instruction's boundary.  */
  sp = gdbarch_frame_align (gdbarch, sp);
  /* Allocate space for, and then position the breakpoint on the
     stack.  */
  if (gdbarch_inner_than (gdbarch, 1, 2))
    {
      CORE_ADDR bppc = sp;
      gdbarch_breakpoint_from_pc (gdbarch, &bppc, &bplen);
      sp = gdbarch_frame_align (gdbarch, sp - bplen);
      (*bp_addr) = sp;
      /* Should the breakpoint size/location be re-computed here?  */
    }      
  else
    {
      (*bp_addr) = sp;
      gdbarch_breakpoint_from_pc (gdbarch, bp_addr, &bplen);
      sp = gdbarch_frame_align (gdbarch, sp + bplen);
    }
  /* Inferior resumes at the function entry point.  */
  (*real_pc) = funaddr;
  return sp;
}

/* Provide backward compatibility.  Once DEPRECATED_FIX_CALL_DUMMY is
   eliminated, this can be simplified.  */

static CORE_ADDR
push_dummy_code (struct gdbarch *gdbarch,
                 CORE_ADDR sp, CORE_ADDR funaddr, int using_gcc,
                 struct value **args, int nargs,
                 struct type *value_type,
                 CORE_ADDR *real_pc, CORE_ADDR *bp_addr)
{
  if (gdbarch_push_dummy_code_p (gdbarch))
    return gdbarch_push_dummy_code (gdbarch, sp, funaddr, using_gcc,
                                    args, nargs, value_type, real_pc, bp_addr);
  else if (DEPRECATED_FIX_CALL_DUMMY_P ())
    return legacy_push_dummy_code (gdbarch, sp, funaddr, using_gcc,
                                   args, nargs, value_type, real_pc, bp_addr);
  else    
    return generic_push_dummy_code (gdbarch, sp, funaddr, using_gcc,
                                    args, nargs, value_type, real_pc, bp_addr);
}

/* All this stuff with a dummy frame may seem unnecessarily complicated
   (why not just save registers in GDB?).  The purpose of pushing a dummy
   frame which looks just like a real frame is so that if you call a
   function and then hit a breakpoint (get a signal, etc), "backtrace"
   will look right.  Whether the backtrace needs to actually show the
   stack at the time the inferior function was called is debatable, but
   it certainly needs to not display garbage.  So if you are contemplating
   making dummy frames be different from normal frames, consider that.  */

/* Perform a function call in the inferior.
   ARGS is a vector of values of arguments (NARGS of them).
   FUNCTION is a value, the function to be called.
   Returns a value representing what the function returned.
   May fail to return, if a breakpoint or signal is hit
   during the execution of the function.

   ARGS is modified to contain coerced values. */

struct value *
call_function_by_hand (struct value *function, int nargs, struct value **args)
{
  register CORE_ADDR sp;
  CORE_ADDR dummy_addr;
  struct type *value_type;
  unsigned char struct_return;
  CORE_ADDR struct_addr = 0;
  struct regcache *retbuf;
  struct cleanup *retbuf_cleanup;
  struct inferior_status *inf_status;
  struct cleanup *inf_status_cleanup;
  CORE_ADDR funaddr;
  int using_gcc;                /* Set to version of gcc in use, or zero if not gcc */
  CORE_ADDR real_pc;
  struct type *ftype = check_typedef (SYMBOL_TYPE (function));
  CORE_ADDR bp_addr;

  if (!target_has_execution)
    noprocess ();

  /* Create a cleanup chain that contains the retbuf (buffer
     containing the register values).  This chain is create BEFORE the
     inf_status chain so that the inferior status can cleaned up
     (restored or discarded) without having the retbuf freed.  */
  retbuf = regcache_xmalloc (current_gdbarch);
  retbuf_cleanup = make_cleanup_regcache_xfree (retbuf);

  /* A cleanup for the inferior status.  Create this AFTER the retbuf
     so that this can be discarded or applied without interfering with
     the regbuf.  */
  inf_status = save_inferior_status (1);
  inf_status_cleanup = make_cleanup_restore_inferior_status (inf_status);

  if (DEPRECATED_PUSH_DUMMY_FRAME_P ())
    {
      /* DEPRECATED_PUSH_DUMMY_FRAME is responsible for saving the
         inferior registers (and frame_pop() for restoring them).  (At
         least on most machines) they are saved on the stack in the
         inferior.  */
      DEPRECATED_PUSH_DUMMY_FRAME;
    }
  else
    {
      /* FIXME: cagney/2003-02-26: Step zero of this little tinker is
      to extract the generic dummy frame code from the architecture
      vector.  Hence this direct call.

      A follow-on change is to modify this interface so that it takes
      thread OR frame OR tpid as a parameter, and returns a dummy
      frame handle.  The handle can then be used further down as a
      parameter SAVE_DUMMY_FRAME_TOS.  Hmm, thinking about it, since
      everything is ment to be using generic dummy frames, why not
      even use some of the dummy frame code to here - do a regcache
      dup and then pass the duped regcache, along with all the other
      stuff, at one single point.

      In fact, you can even save the structure's return address in the
      dummy frame and fix one of those nasty lost struct return edge
      conditions.  */
      generic_push_dummy_frame ();
    }

  /* Ensure that the initial SP is correctly aligned.  */
  {
    CORE_ADDR old_sp = read_sp ();
    if (gdbarch_frame_align_p (current_gdbarch))
      {
        /* NOTE: cagney/2002-09-18:
           
           On a RISC architecture, a void parameterless generic dummy
           frame (i.e., no parameters, no result) typically does not
           need to push anything the stack and hence can leave SP and
           FP.  Similarly, a framelss (possibly leaf) function does
           not push anything on the stack and, hence, that too can
           leave FP and SP unchanged.  As a consequence, a sequence of
           void parameterless generic dummy frame calls to frameless
           functions will create a sequence of effectively identical
           frames (SP, FP and TOS and PC the same).  This, not
           suprisingly, results in what appears to be a stack in an
           infinite loop --- when GDB tries to find a generic dummy
           frame on the internal dummy frame stack, it will always
           find the first one.

           To avoid this problem, the code below always grows the
           stack.  That way, two dummy frames can never be identical.
           It does burn a few bytes of stack but that is a small price
           to pay :-).  */
        sp = gdbarch_frame_align (current_gdbarch, old_sp);
        if (sp == old_sp)
          {
            if (INNER_THAN (1, 2))
              /* Stack grows down.  */
              sp = gdbarch_frame_align (current_gdbarch, old_sp - 1);
            else
              /* Stack grows up.  */
              sp = gdbarch_frame_align (current_gdbarch, old_sp + 1);
          }
        gdb_assert ((INNER_THAN (1, 2) && sp <= old_sp)
                    || (INNER_THAN (2, 1) && sp >= old_sp));
      }
    else
      /* FIXME: cagney/2002-09-18: Hey, you loose!  Who knows how
         badly aligned the SP is!  Further, per comment above, if the
         generic dummy frame ends up empty (because nothing is pushed)
         GDB won't be able to correctly perform back traces.  If a
         target is having trouble with backtraces, first thing to do
         is add FRAME_ALIGN() to its architecture vector.  After that,
         try adding SAVE_DUMMY_FRAME_TOS() and modifying
         DEPRECATED_FRAME_CHAIN so that when the next outer frame is a
         generic dummy, it returns the current frame's base.  */
      sp = old_sp;
  }

  funaddr = find_function_addr (function, &value_type);
  CHECK_TYPEDEF (value_type);

  {
    struct block *b = block_for_pc (funaddr);
    /* If compiled without -g, assume GCC 2.  */
    using_gcc = (b == NULL ? 2 : BLOCK_GCC_COMPILED (b));
  }

  /* Are we returning a value using a structure return or a normal
     value return? */

  struct_return = using_struct_return (function, funaddr, value_type,
                                       using_gcc);

  /* Determine the location of the breakpoint (and possibly other
     stuff) that the called function will return to.  The SPARC, for a
     function returning a structure or union, needs to make space for
     not just the breakpoint but also an extra word containing the
     size (?) of the structure being passed.  */

  /* The actual breakpoint (at BP_ADDR) is inserted separatly so there
     is no need to write that out.  */

  switch (CALL_DUMMY_LOCATION)
    {
    case ON_STACK:
      /* "dummy_addr" is here just to keep old targets happy.  New
         targets return that same information via "sp" and "bp_addr".  */
      if (INNER_THAN (1, 2))
        {
          sp = push_dummy_code (current_gdbarch, sp, funaddr,
                                using_gcc, args, nargs, value_type,
                                &real_pc, &bp_addr);
          dummy_addr = sp;
        }
      else
        {
          dummy_addr = sp;
          sp = push_dummy_code (current_gdbarch, sp, funaddr,
                                using_gcc, args, nargs, value_type,
                                &real_pc, &bp_addr);
        }
      break;
    case AT_ENTRY_POINT:
      if (DEPRECATED_FIX_CALL_DUMMY_P ())
        {
          /* Sigh.  Some targets use DEPRECATED_FIX_CALL_DUMMY to
             shove extra stuff onto the stack or into registers.  That
             code should be in PUSH_DUMMY_CALL, however, in the mean
             time ...  */
          /* If the target is manipulating DUMMY1, it looses big time.  */
          void *dummy1 = NULL;
          DEPRECATED_FIX_CALL_DUMMY (dummy1, sp, funaddr, nargs, args,
                                     value_type, using_gcc);
        }
      real_pc = funaddr;
      dummy_addr = CALL_DUMMY_ADDRESS ();
      /* A call dummy always consists of just a single breakpoint, so
         it's address is the same as the address of the dummy.  */
      bp_addr = dummy_addr;
      break;
    default:
      internal_error (__FILE__, __LINE__, "bad switch");
    }

  if (DEPRECATED_USE_GENERIC_DUMMY_FRAMES)
    /* Save where the breakpoint is going to be inserted so that the
       dummy-frame code is later able to re-identify it.  */
    generic_save_call_dummy_addr (bp_addr, bp_addr + 1);

  if (nargs < TYPE_NFIELDS (ftype))
    error ("too few arguments in function call");

  {
    int i;
    for (i = nargs - 1; i >= 0; i--)
      {
        int prototyped;
        struct type *param_type;
        
        /* FIXME drow/2002-05-31: Should just always mark methods as
           prototyped.  Can we respect TYPE_VARARGS?  Probably not.  */
        if (TYPE_CODE (ftype) == TYPE_CODE_METHOD)
          prototyped = 1;
        else if (i < TYPE_NFIELDS (ftype))
          prototyped = TYPE_PROTOTYPED (ftype);
        else
          prototyped = 0;

        if (i < TYPE_NFIELDS (ftype))
          param_type = TYPE_FIELD_TYPE (ftype, i);
        else
          param_type = NULL;
        
        args[i] = value_arg_coerce (args[i], param_type, prototyped);

        /* elz: this code is to handle the case in which the function
           to be called has a pointer to function as parameter and the
           corresponding actual argument is the address of a function
           and not a pointer to function variable.  In aCC compiled
           code, the calls through pointers to functions (in the body
           of the function called by hand) are made via
           $$dyncall_external which requires some registers setting,
           this is taken care of if we call via a function pointer
           variable, but not via a function address.  In cc this is
           not a problem. */

        if (using_gcc == 0)
          {
            if (param_type != NULL && TYPE_CODE (ftype) != TYPE_CODE_METHOD)
              {
                /* if this parameter is a pointer to function.  */
                if (TYPE_CODE (param_type) == TYPE_CODE_PTR)
                  if (TYPE_CODE (TYPE_TARGET_TYPE (param_type)) == TYPE_CODE_FUNC)
                    /* elz: FIXME here should go the test about the
                       compiler used to compile the target. We want to
                       issue the error message only if the compiler
                       used was HP's aCC.  If we used HP's cc, then
                       there is no problem and no need to return at
                       this point.  */
                    /* Go see if the actual parameter is a variable of
                       type pointer to function or just a function.  */
                    if (args[i]->lval == not_lval)
                      {
                        char *arg_name;
                        if (find_pc_partial_function ((CORE_ADDR) args[i]->aligner.contents[0], &arg_name, NULL, NULL))
                          error ("\
You cannot use function <%s> as argument. \n\
You must use a pointer to function type variable. Command ignored.", arg_name);
                      }
              }
          }
      }
  }

  if (REG_STRUCT_HAS_ADDR_P ())
    {
      int i;
      /* This is a machine like the sparc, where we may need to pass a
         pointer to the structure, not the structure itself.  */
      for (i = nargs - 1; i >= 0; i--)
        {
          struct type *arg_type = check_typedef (VALUE_TYPE (args[i]));
          if ((TYPE_CODE (arg_type) == TYPE_CODE_STRUCT
               || TYPE_CODE (arg_type) == TYPE_CODE_UNION
               || TYPE_CODE (arg_type) == TYPE_CODE_ARRAY
               || TYPE_CODE (arg_type) == TYPE_CODE_STRING
               || TYPE_CODE (arg_type) == TYPE_CODE_BITSTRING
               || TYPE_CODE (arg_type) == TYPE_CODE_SET
               || (TYPE_CODE (arg_type) == TYPE_CODE_FLT
                   && TYPE_LENGTH (arg_type) > 8)
               )
              && REG_STRUCT_HAS_ADDR (using_gcc, arg_type))
            {
              CORE_ADDR addr;
              int len;          /*  = TYPE_LENGTH (arg_type); */
              int aligned_len;
              arg_type = check_typedef (VALUE_ENCLOSING_TYPE (args[i]));
              len = TYPE_LENGTH (arg_type);

              if (STACK_ALIGN_P ())
                /* MVS 11/22/96: I think at least some of this
                   stack_align code is really broken.  Better to let
                   PUSH_ARGUMENTS adjust the stack in a target-defined
                   manner.  */
                aligned_len = STACK_ALIGN (len);
              else
                aligned_len = len;
              if (INNER_THAN (1, 2))
                {
                  /* stack grows downward */
                  sp -= aligned_len;
                  /* ... so the address of the thing we push is the
                     stack pointer after we push it.  */
                  addr = sp;
                }
              else
                {
                  /* The stack grows up, so the address of the thing
                     we push is the stack pointer before we push it.  */
                  addr = sp;
                  sp += aligned_len;
                }
              /* Push the structure.  */
              write_memory (addr, VALUE_CONTENTS_ALL (args[i]), len);
              /* The value we're going to pass is the address of the
                 thing we just pushed.  */
              /*args[i] = value_from_longest (lookup_pointer_type (value_type),
                (LONGEST) addr); */
              args[i] = value_from_pointer (lookup_pointer_type (arg_type),
                                            addr);
            }
        }
    }


  /* Reserve space for the return structure to be written on the
     stack, if necessary.  Make certain that the value is correctly
     aligned. */

  if (struct_return)
    {
      int len = TYPE_LENGTH (value_type);
      if (STACK_ALIGN_P ())
        /* NOTE: cagney/2003-03-22: Should rely on frame align, rather
           than stack align to force the alignment of the stack.  */
        len = STACK_ALIGN (len);
      if (INNER_THAN (1, 2))
        {
          /* Stack grows downward.  Align STRUCT_ADDR and SP after
             making space for the return value.  */
          sp -= len;
          if (gdbarch_frame_align_p (current_gdbarch))
            sp = gdbarch_frame_align (current_gdbarch, sp);
          struct_addr = sp;
        }
      else
        {
          /* Stack grows upward.  Align the frame, allocate space, and
             then again, re-align the frame??? */
          if (gdbarch_frame_align_p (current_gdbarch))
            sp = gdbarch_frame_align (current_gdbarch, sp);
          struct_addr = sp;
          sp += len;
          if (gdbarch_frame_align_p (current_gdbarch))
            sp = gdbarch_frame_align (current_gdbarch, sp);
        }
    }

  /* elz: on HPPA no need for this extra alignment, maybe it is needed
     on other architectures. This is because all the alignment is
     taken care of in the above code (ifdef REG_STRUCT_HAS_ADDR) and
     in hppa_push_arguments */
  /* NOTE: cagney/2003-03-24: The below code is very broken.  Given an
     odd sized parameter the below will mis-align the stack.  As was
     suggested back in '96, better to let PUSH_ARGUMENTS handle it.  */
  if (DEPRECATED_EXTRA_STACK_ALIGNMENT_NEEDED)
    {
      /* MVS 11/22/96: I think at least some of this stack_align code
         is really broken.  Better to let push_dummy_call() adjust the
         stack in a target-defined manner.  */
      if (STACK_ALIGN_P () && INNER_THAN (1, 2))
        {
          /* If stack grows down, we must leave a hole at the top. */
          int len = 0;
          int i;
          for (i = nargs - 1; i >= 0; i--)
            len += TYPE_LENGTH (VALUE_ENCLOSING_TYPE (args[i]));
          if (DEPRECATED_CALL_DUMMY_STACK_ADJUST_P ())
            len += DEPRECATED_CALL_DUMMY_STACK_ADJUST;
          sp -= STACK_ALIGN (len) - len;
        }
    }

  /* Create the dummy stack frame.  Pass in the call dummy address as,
     presumably, the ABI code knows where, in the call dummy, the
     return address should be pointed.  */
  if (gdbarch_push_dummy_call_p (current_gdbarch))
    /* When there is no push_dummy_call method, should this code
       simply error out.  That would the implementation of this method
       for all ABIs (which is probably a good thing).  */
    sp = gdbarch_push_dummy_call (current_gdbarch, funaddr, current_regcache,
                                  bp_addr, nargs, args, sp, struct_return,
                                  struct_addr);
  else  if (DEPRECATED_PUSH_ARGUMENTS_P ())
    /* Keep old targets working.  */
    sp = DEPRECATED_PUSH_ARGUMENTS (nargs, args, sp, struct_return,
                                    struct_addr);
  else
    sp = legacy_push_arguments (nargs, args, sp, struct_return, struct_addr);

  if (DEPRECATED_PUSH_RETURN_ADDRESS_P ())
    /* for targets that use no CALL_DUMMY */
    /* There are a number of targets now which actually don't write
       any CALL_DUMMY instructions into the target, but instead just
       save the machine state, push the arguments, and jump directly
       to the callee function.  Since this doesn't actually involve
       executing a JSR/BSR instruction, the return address must be set
       up by hand, either by pushing onto the stack or copying into a
       return-address register as appropriate.  Formerly this has been
       done in PUSH_ARGUMENTS, but that's overloading its
       functionality a bit, so I'm making it explicit to do it here.  */
    /* NOTE: cagney/2003-04-22: The first parameter ("real_pc") has
       been replaced with zero, it turns out that no implementation
       used that parameter.  This occured because the value being
       supplied - the address of the called function's entry point
       instead of the address of the breakpoint that the called
       function should return to - wasn't useful.  */
    sp = DEPRECATED_PUSH_RETURN_ADDRESS (0, sp);

  /* NOTE: cagney/2003-03-23: Diable this code when there is a
     push_dummy_call() method.  Since that method will have already
     handled any alignment issues, the code below is entirely
     redundant.  */
  if (!gdbarch_push_dummy_call_p (current_gdbarch)
      && STACK_ALIGN_P () && !INNER_THAN (1, 2))
    {
      /* If stack grows up, we must leave a hole at the bottom, note
         that sp already has been advanced for the arguments!  */
      if (DEPRECATED_CALL_DUMMY_STACK_ADJUST_P ())
        sp += DEPRECATED_CALL_DUMMY_STACK_ADJUST;
      sp = STACK_ALIGN (sp);
    }

/* XXX This seems wrong.  For stacks that grow down we shouldn't do
   anything here!  */
  /* MVS 11/22/96: I think at least some of this stack_align code is
     really broken.  Better to let PUSH_ARGUMENTS adjust the stack in
     a target-defined manner.  */
  if (DEPRECATED_CALL_DUMMY_STACK_ADJUST_P ())
    if (INNER_THAN (1, 2))
      {
        /* stack grows downward */
        sp -= DEPRECATED_CALL_DUMMY_STACK_ADJUST;
      }

  /* Store the address at which the structure is supposed to be
     written.  */
  /* NOTE: 2003-03-24: Since PUSH_ARGUMENTS can (and typically does)
     store the struct return address, this call is entirely redundant.  */
  if (struct_return && DEPRECATED_STORE_STRUCT_RETURN_P ())
    DEPRECATED_STORE_STRUCT_RETURN (struct_addr, sp);

  /* Write the stack pointer.  This is here because the statements
     above might fool with it.  On SPARC, this write also stores the
     register window into the right place in the new stack frame,
     which otherwise wouldn't happen (see store_inferior_registers in
     sparc-nat.c).  */
  /* NOTE: cagney/2003-03-23: Since the architecture method
     push_dummy_call() should have already stored the stack pointer
     (as part of creating the fake call frame), and none of the code
     following that call adjusts the stack-pointer value, the below
     call is entirely redundant.  */
  if (DEPRECATED_DUMMY_WRITE_SP_P ())
    DEPRECATED_DUMMY_WRITE_SP (sp);

  if (SAVE_DUMMY_FRAME_TOS_P ())
    SAVE_DUMMY_FRAME_TOS (sp);

  /* Now proceed, having reached the desired place.  */
  clear_proceed_status ();
    
  /* Create a momentary breakpoint at the return address of the
     inferior.  That way it breaks when it returns.  */

  {
    struct breakpoint *bpt;
    struct symtab_and_line sal;
    struct frame_id frame;
    init_sal (&sal);            /* initialize to zeroes */
    sal.pc = bp_addr;
    sal.section = find_pc_overlay (sal.pc);
    /* Set up a frame ID for the dummy frame so we can pass it to
       set_momentary_breakpoint.  We need to give the breakpoint a
       frame ID so that the breakpoint code can correctly re-identify
       the dummy breakpoint.  */
    /* The assumption here is that push_dummy_call() returned the
       stack part of the frame ID.  Unfortunatly, many older
       architectures were, via a convoluted mess, relying on the
       poorly defined and greatly overloaded DEPRECATED_TARGET_READ_FP
       or DEPRECATED_FP_REGNUM to supply the value.  */
    if (DEPRECATED_TARGET_READ_FP_P ())
      frame = frame_id_build (DEPRECATED_TARGET_READ_FP (), sal.pc);
    else if (DEPRECATED_FP_REGNUM >= 0)
      frame = frame_id_build (read_register (DEPRECATED_FP_REGNUM), sal.pc);
    else
      frame = frame_id_build (sp, sal.pc);
    bpt = set_momentary_breakpoint (sal, frame, bp_call_dummy);
    bpt->disposition = disp_del;
  }

  /* Execute a "stack dummy", a piece of code stored in the stack by
     the debugger to be executed in the inferior.

     The dummy's frame is automatically popped whenever that break is
     hit.  If that is the first time the program stops,
     call_function_by_hand returns to its caller with that frame
     already gone and sets RC to 0.
   
     Otherwise, set RC to a non-zero value.  If the called function
     receives a random signal, we do not allow the user to continue
     executing it as this may not work.  The dummy frame is poped and
     we return 1.  If we hit a breakpoint, we leave the frame in place
     and return 2 (the frame will eventually be popped when we do hit
     the dummy end breakpoint).  */

  {
    struct cleanup *old_cleanups = make_cleanup (null_cleanup, 0);
    int saved_async = 0;

    /* If all error()s out of proceed ended up calling normal_stop
       (and perhaps they should; it already does in the special case
       of error out of resume()), then we wouldn't need this.  */
    make_cleanup (breakpoint_auto_delete_contents, &stop_bpstat);

    disable_watchpoints_before_interactive_call_start ();
    proceed_to_finish = 1;      /* We want stop_registers, please... */

    if (target_can_async_p ())
      saved_async = target_async_mask (0);
    
    proceed (real_pc, TARGET_SIGNAL_0, 0);
    
    if (saved_async)
      target_async_mask (saved_async);
    
    enable_watchpoints_after_interactive_call_stop ();
      
    discard_cleanups (old_cleanups);
  }

  if (stopped_by_random_signal || !stop_stack_dummy)
    {
      /* Find the name of the function we're about to complain about.  */
      char *name = NULL;
      {
        struct symbol *symbol = find_pc_function (funaddr);
        if (symbol)
          name = SYMBOL_PRINT_NAME (symbol);
        else
          {
            /* Try the minimal symbols.  */
            struct minimal_symbol *msymbol = lookup_minimal_symbol_by_pc (funaddr);
            if (msymbol)
              name = SYMBOL_PRINT_NAME (msymbol);
          }
      }
      if (name == NULL)
        {
          /* NOTE: cagney/2003-04-23: Don't blame me.  This code dates
             back to 1993-07-08, I simply moved it.  */
          char format[80];
          sprintf (format, "at %s", local_hex_format ());
          name = alloca (80);
          /* FIXME-32x64: assumes funaddr fits in a long.  */
          sprintf (name, format, (unsigned long) funaddr);
        }
      if (stopped_by_random_signal)
        {
          /* We stopped inside the FUNCTION because of a random
             signal.  Further execution of the FUNCTION is not
             allowed. */

          if (unwind_on_signal_p)
            {
              /* The user wants the context restored. */

              /* We must get back to the frame we were before the
                 dummy call. */
              frame_pop (get_current_frame ());

              /* FIXME: Insert a bunch of wrap_here; name can be very
                 long if it's a C++ name with arguments and stuff.  */
              error ("\
The program being debugged was signaled while in a function called from GDB.\n\
GDB has restored the context to what it was before the call.\n\
To change this behavior use \"set unwindonsignal off\"\n\
Evaluation of the expression containing the function (%s) will be abandoned.",
                     name);
            }
          else
            {
              /* The user wants to stay in the frame where we stopped
                 (default).*/
              /* If we restored the inferior status (via the cleanup),
                 we would print a spurious error message (Unable to
                 restore previously selected frame), would write the
                 registers from the inf_status (which is wrong), and
                 would do other wrong things.  */
              discard_cleanups (inf_status_cleanup);
              discard_inferior_status (inf_status);
              /* FIXME: Insert a bunch of wrap_here; name can be very
                 long if it's a C++ name with arguments and stuff.  */
              error ("\
The program being debugged was signaled while in a function called from GDB.\n\
GDB remains in the frame where the signal was received.\n\
To change this behavior use \"set unwindonsignal on\"\n\
Evaluation of the expression containing the function (%s) will be abandoned.",
                     name);
            }
        }

      if (!stop_stack_dummy)
        {
          /* We hit a breakpoint inside the FUNCTION. */
          /* If we restored the inferior status (via the cleanup), we
             would print a spurious error message (Unable to restore
             previously selected frame), would write the registers
             from the inf_status (which is wrong), and would do other
             wrong things.  */
          discard_cleanups (inf_status_cleanup);
          discard_inferior_status (inf_status);
          /* The following error message used to say "The expression
             which contained the function call has been discarded."
             It is a hard concept to explain in a few words.  Ideally,
             GDB would be able to resume evaluation of the expression
             when the function finally is done executing.  Perhaps
             someday this will be implemented (it would not be easy).  */
          /* FIXME: Insert a bunch of wrap_here; name can be very long if it's
             a C++ name with arguments and stuff.  */
          error ("\
The program being debugged stopped while in a function called from GDB.\n\
When the function (%s) is done executing, GDB will silently\n\
stop (instead of continuing to evaluate the expression containing\n\
the function call).", name);
        }

      /* The above code errors out, so ...  */
      internal_error (__FILE__, __LINE__, "... should not be here");
    }

  /* If we get here the called FUNCTION run to completion. */

  /* On normal return, the stack dummy has been popped already.  */
  regcache_cpy_no_passthrough (retbuf, stop_registers);

  /* Restore the inferior status, via its cleanup.  At this stage,
     leave the RETBUF alone.  */
  do_cleanups (inf_status_cleanup);

  /* Figure out the value returned by the function.  */
  /* elz: I defined this new macro for the hppa architecture only.
     this gives us a way to get the value returned by the function
     from the stack, at the same address we told the function to put
     it.  We cannot assume on the pa that r28 still contains the
     address of the returned structure. Usually this will be
     overwritten by the callee.  I don't know about other
     architectures, so I defined this macro */
#ifdef VALUE_RETURNED_FROM_STACK
  if (struct_return)
    {
      do_cleanups (retbuf_cleanup);
      return VALUE_RETURNED_FROM_STACK (value_type, struct_addr);
    }
#endif
  /* NOTE: cagney/2002-09-10: Only when the stack has been correctly
     aligned (using frame_align()) do we can trust STRUCT_ADDR and
     fetch the return value direct from the stack.  This lack of trust
     comes about because legacy targets have a nasty habit of
     silently, and local to PUSH_ARGUMENTS(), moving STRUCT_ADDR.  For
     such targets, just hope that value_being_returned() can find the
     adjusted value.  */
  if (struct_return && gdbarch_frame_align_p (current_gdbarch))
    {
      struct value *retval = value_at (value_type, struct_addr, NULL);
      do_cleanups (retbuf_cleanup);
      return retval;
    }
  else
    {
      struct value *retval = value_being_returned (value_type, retbuf,
                                                   struct_return);
      do_cleanups (retbuf_cleanup);
      return retval;
    }
}

void _initialize_infcall (void);

void
_initialize_infcall (void)
{
  add_setshow_boolean_cmd ("coerce-float-to-double", class_obscure,
                           &coerce_float_to_double_p, "\
Set coercion of floats to doubles when calling functions\n\
Variables of type float should generally be converted to doubles before\n\
calling an unprototyped function, and left alone when calling a prototyped\n\
function.  However, some older debug info formats do not provide enough\n\
information to determine that a function is prototyped.  If this flag is\n\
set, GDB will perform the conversion for a function it considers\n\
unprototyped.\n\
The default is to perform the conversion.\n", "\
Show coercion of floats to doubles when calling functions\n\
Variables of type float should generally be converted to doubles before\n\
calling an unprototyped function, and left alone when calling a prototyped\n\
function.  However, some older debug info formats do not provide enough\n\
information to determine that a function is prototyped.  If this flag is\n\
set, GDB will perform the conversion for a function it considers\n\
unprototyped.\n\
The default is to perform the conversion.\n",
                           NULL, NULL, &setlist, &showlist);

  add_setshow_boolean_cmd ("unwindonsignal", no_class,
                           &unwind_on_signal_p, "\
Set unwinding of stack if a signal is received while in a call dummy.\n\
The unwindonsignal lets the user determine what gdb should do if a signal\n\
is received while in a function called from gdb (call dummy).  If set, gdb\n\
unwinds the stack and restore the context to what as it was before the call.\n\
The default is to stop in the frame where the signal was received.", "\
Set unwinding of stack if a signal is received while in a call dummy.\n\
The unwindonsignal lets the user determine what gdb should do if a signal\n\
is received while in a function called from gdb (call dummy).  If set, gdb\n\
unwinds the stack and restore the context to what as it was before the call.\n\
The default is to stop in the frame where the signal was received.",
                           NULL, NULL, &setlist, &showlist);
}