method.c

gcc库的原代码,对编程有很大帮助.

	  cname = TREE_OPERAND (tmp, 0);
	  tmp = TREE_OPERAND (tmp, 1);
	  break;

	default:
	  my_friendly_abort (77);
	}
      last = tmp;
      tmp = TREE_OPERAND (tmp, 0);
    }

  last = groktypename (build_tree_list (TREE_TYPE (component), TREE_OPERAND (component, 0)));
  name = build_typename_overload (last);
  TREE_TYPE (name) = last;
  if (of && TREE_CODE (of) == TYPE_DECL)
    {
      if (cname == NULL_TREE)
	{
	  cname = DECL_NAME (of);
	  of = NULL_TREE;
	}
      else my_friendly_assert (cname == DECL_NAME (of), 256);
    }

  if (of)
    {
      tree this_this;

      if (current_class_decl == NULL_TREE)
	{
	  cp_error ("object required for `operator %T' call",
		    TREE_TYPE (name));
	  return error_mark_node;
	}

      this_this = convert_pointer_to (TREE_TYPE (of), current_class_decl);
      return build_component_ref (this_this, name, 0, protect);
    }
  else if (cname)
    return build_offset_ref (cname, name);
  else if (current_class_name)
    return build_offset_ref (current_class_name, name);

  cp_error ("object required for `operator %T' member reference",
	    TREE_TYPE (name));
  return error_mark_node;
}
#endif

static char *
thunk_printable_name (decl)
     tree decl;
{
  return "<thunk function>";
}

tree
make_thunk (function, delta)
     tree function;
     int delta;
{
  char buffer[250];
  tree thunk_fndecl, thunk_id;
  tree thunk;
  char *func_name;
  static int thunk_number = 0;
  tree func_decl;
  if (TREE_CODE (function) != ADDR_EXPR)
    abort ();
  func_decl = TREE_OPERAND (function, 0);
  if (TREE_CODE (func_decl) != FUNCTION_DECL)
    abort ();
  func_name = IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (func_decl));
  if (delta<=0)
    sprintf (buffer, "__thunk_%d_%s", -delta, func_name);
  else
    sprintf (buffer, "__thunk_n%d_%s", delta, func_name);
  thunk_id = get_identifier (buffer);
  thunk = IDENTIFIER_GLOBAL_VALUE (thunk_id);
  if (thunk && TREE_CODE (thunk) != THUNK_DECL)
    {
      error_with_decl ("implementation-reserved name `%s' used");
      IDENTIFIER_GLOBAL_VALUE (thunk_id) = thunk = NULL_TREE;
    }
  if (thunk == NULL_TREE)
    {
      thunk = build_decl (THUNK_DECL, thunk_id, TREE_TYPE (func_decl));
      DECL_RESULT (thunk)
	= build_decl (RESULT_DECL, 0, TYPE_MAIN_VARIANT (TREE_TYPE (vtable_entry_type)));
      TREE_READONLY (thunk) = TYPE_READONLY (TREE_TYPE (vtable_entry_type));
      TREE_THIS_VOLATILE (thunk) = TYPE_VOLATILE (TREE_TYPE (vtable_entry_type));
      make_function_rtl (thunk);
      DECL_INITIAL (thunk) = function;
      THUNK_DELTA (thunk) = delta;
      /* So that finish_file can write out any thunks that need to be: */
      pushdecl_top_level (thunk);
    }
  return thunk;
}

void
emit_thunk (thunk_fndecl)
  tree thunk_fndecl;
{
  rtx insns;
  char *fnname;
  char buffer[250];
  tree argp;
  struct args_size stack_args_size;
  tree function = TREE_OPERAND (DECL_INITIAL (thunk_fndecl), 0);
  int delta = THUNK_DELTA (thunk_fndecl);
  int tem;
  int failure = 0;
  int current_call_is_indirect = 0;	/* needed for HPPA FUNCTION_ARG */

  /* Used to remember which regs we need to emit a USE rtx for. */
  rtx need_use[FIRST_PSEUDO_REGISTER];
  int need_use_count = 0;

  /* rtx for the 'this' parameter. */
  rtx this_rtx = 0, this_reg_rtx = 0, fixed_this_rtx;

  char *(*save_decl_printable_name) () = decl_printable_name;
  /* Data on reg parms scanned so far.  */
  CUMULATIVE_ARGS args_so_far;

  if (TREE_ASM_WRITTEN (thunk_fndecl))
    return;

  TREE_ASM_WRITTEN (thunk_fndecl) = 1;

  if (TREE_PUBLIC (function))
    {
      TREE_PUBLIC (thunk_fndecl) = 1;
      if (DECL_EXTERNAL (function))
	{
	  DECL_EXTERNAL (thunk_fndecl) = 1;
	  assemble_external (thunk_fndecl);
	  return;
	}
    }

  decl_printable_name = thunk_printable_name;
  if (current_function_decl)
    abort ();
  current_function_decl = thunk_fndecl;
  init_function_start (thunk_fndecl, input_filename, lineno);
  pushlevel (0);
  expand_start_bindings (1);

  /* Start updating where the next arg would go.  */
  INIT_CUMULATIVE_ARGS (args_so_far, TREE_TYPE (function), NULL_RTX);
  stack_args_size.constant = 0;
  stack_args_size.var = 0;
  /* SETUP for possible structure return address FIXME */

  /* Now look through all the parameters, make sure that we
     don't clobber any registers used for parameters.
     Also, pick up an rtx for the first "this" parameter. */
  for (argp = TYPE_ARG_TYPES (TREE_TYPE (function));
       argp != NULL_TREE;
       argp = TREE_CHAIN (argp))

    {
      tree passed_type = TREE_VALUE (argp);
      register rtx entry_parm;
      int named = 1; /* FIXME */
      struct args_size stack_offset;
      struct args_size arg_size;

      if (passed_type == void_type_node)
	break;

      if ((TREE_CODE (TYPE_SIZE (passed_type)) != INTEGER_CST
	   && contains_placeholder_p (TYPE_SIZE (passed_type)))
#ifdef FUNCTION_ARG_PASS_BY_REFERENCE
	  || FUNCTION_ARG_PASS_BY_REFERENCE (args_so_far,
					     TYPE_MODE (passed_type),
					     passed_type, named)
#endif
	  )
	passed_type = build_pointer_type (passed_type);

      entry_parm = FUNCTION_ARG (args_so_far,
				 TYPE_MODE (passed_type),
				 passed_type,
				 named);
      if (entry_parm != 0)
	need_use[need_use_count++] = entry_parm;

      locate_and_pad_parm (TYPE_MODE (passed_type), passed_type,
#ifdef STACK_PARMS_IN_REG_PARM_AREA
			   1,
#else
			   entry_parm != 0,
#endif
			   thunk_fndecl,
			   &stack_args_size, &stack_offset, &arg_size);

/*    REGNO (entry_parm);*/
      if (this_rtx == 0)
	{
	  this_reg_rtx = entry_parm;
	  if (!entry_parm)
	    {
	      rtx offset_rtx = ARGS_SIZE_RTX (stack_offset);

	      rtx internal_arg_pointer, stack_parm;

	      if ((ARG_POINTER_REGNUM == STACK_POINTER_REGNUM
		   || ! (fixed_regs[ARG_POINTER_REGNUM]
			 || ARG_POINTER_REGNUM == FRAME_POINTER_REGNUM)))
		internal_arg_pointer = copy_to_reg (virtual_incoming_args_rtx);
	      else
		internal_arg_pointer = virtual_incoming_args_rtx;

	      if (offset_rtx == const0_rtx)
		entry_parm = gen_rtx (MEM, TYPE_MODE (passed_type),
				      internal_arg_pointer);
	      else
		entry_parm = gen_rtx (MEM, TYPE_MODE (passed_type),
				      gen_rtx (PLUS, Pmode,
					       internal_arg_pointer, 
					       offset_rtx));
	    }
	  
	  this_rtx = entry_parm;
	}

      FUNCTION_ARG_ADVANCE (args_so_far,
			    TYPE_MODE (passed_type),
			    passed_type,
			    named);
    }

  fixed_this_rtx = plus_constant (this_rtx, delta);
  if (this_rtx != fixed_this_rtx)
    emit_move_insn (this_rtx, fixed_this_rtx);

  if (this_reg_rtx)
    emit_insn (gen_rtx (USE, VOIDmode, this_reg_rtx));

  emit_indirect_jump (XEXP (DECL_RTL (function), 0));

  while (need_use_count > 0)
    emit_insn (gen_rtx (USE, VOIDmode, need_use[--need_use_count]));

  expand_end_bindings (NULL, 1, 0);
  poplevel (0, 0, 1);

  /* From now on, allocate rtl in current_obstack, not in saveable_obstack.
     Note that that may have been done above, in save_for_inline_copying.
     The call to resume_temporary_allocation near the end of this function
     goes back to the usual state of affairs.  */

  rtl_in_current_obstack ();

  insns = get_insns ();

  /* Copy any shared structure that should not be shared.  */

  unshare_all_rtl (insns);

  /* Instantiate all virtual registers.  */

  instantiate_virtual_regs (current_function_decl, get_insns ());

  /* We are no longer anticipating cse in this function, at least.  */

  cse_not_expected = 1;

  /* Now we choose between stupid (pcc-like) register allocation
     (if we got the -noreg switch and not -opt)
     and smart register allocation.  */

  if (optimize > 0)			/* Stupid allocation probably won't work */
    obey_regdecls = 0;		/* if optimizations being done.  */

  regclass_init ();

  regclass (insns, max_reg_num ());
  if (obey_regdecls)
    {
      stupid_life_analysis (insns, max_reg_num (), NULL);
      failure = reload (insns, 0, NULL);
    }
  else
    {
      /* Do control and data flow analysis,
	 and write some of the results to dump file.  */

      flow_analysis (insns, max_reg_num (), NULL);
      local_alloc ();
      failure = global_alloc (NULL);
    }

  reload_completed = 1;

#ifdef LEAF_REGISTERS
  leaf_function = 0;
  if (optimize > 0 && only_leaf_regs_used () && leaf_function_p ())
    leaf_function = 1;
#endif

  /* If a machine dependent reorganization is needed, call it.  */
#ifdef MACHINE_DEPENDENT_REORG
   MACHINE_DEPENDENT_REORG (insns);
#endif

  /* Now turn the rtl into assembler code.  */

    {
      char *fnname = XSTR (XEXP (DECL_RTL (thunk_fndecl), 0), 0);
      assemble_start_function (thunk_fndecl, fnname);
      final (insns, asm_out_file, optimize, 0);
      assemble_end_function (thunk_fndecl, fnname);
    };

 exit_rest_of_compilation:

  reload_completed = 0;

  /* Cancel the effect of rtl_in_current_obstack.  */

  resume_temporary_allocation ();

  decl_printable_name = save_decl_printable_name;
  current_function_decl = 0;
}

/* Code for synthesizing methods which have default semantics defined.  */

/* For the anonymous union in TYPE, return the member that is at least as
   large as the rest of the members, so we can copy it.  */
static tree
largest_union_member (type)
     tree type;
{
  tree f, type_size = TYPE_SIZE (type);

  for (f = TYPE_FIELDS (type); f; f = TREE_CHAIN (f))
    if (simple_cst_equal (DECL_SIZE (f), type_size) == 1)
      return f;

  /* We should always find one.  */
  my_friendly_abort (323);
  return NULL_TREE;
}

/* Generate code for default X(X&) constructor.  */
void
do_build_copy_constructor (fndecl)
     tree fndecl;
{
  tree parm = TREE_CHAIN (DECL_ARGUMENTS (fndecl));
  tree t;

  clear_last_expr ();
  push_momentary ();

  if (TYPE_USES_VIRTUAL_BASECLASSES (current_class_type))
    parm = TREE_CHAIN (parm);
  parm = convert_from_reference (parm);

  if (TYPE_HAS_TRIVIAL_INIT_REF (current_class_type))
    {
      t = build (INIT_EXPR, void_type_node, C_C_D, parm);
      TREE_SIDE_EFFECTS (t) = 1;
      cplus_expand_expr_stmt (t);
    }
  else
    {
      tree fields = TYPE_FIELDS (current_class_type);
      int n_bases = CLASSTYPE_N_BASECLASSES (current_class_type);
      tree binfos = TYPE_BINFO_BASETYPES (current_class_type);
      int i;

      for (t = CLASSTYPE_VBASECLASSES (current_class_type); t;
	   t = TREE_CHAIN (t))
	{
	  tree basetype = BINFO_TYPE (t);
	  tree p = convert_to_reference
	    (build_reference_type (basetype), parm,
	     CONV_IMPLICIT|CONV_CONST, LOOKUP_COMPLAIN, NULL_TREE);
	  p = convert_from_reference (p);
	  current_base_init_list = tree_cons (TYPE_NESTED_NAME (basetype),
					      p, current_base_init_list);
	}
	
      for (i = 0; i < n_bases; ++i)
	{
	  tree p, basetype = TREE_VEC_ELT (binfos, i);
	  if (TREE_VIA_VIRTUAL (basetype))
	    continue; 

	  basetype = BINFO_TYPE (basetype);
	  p = convert_to_reference
	    (build_reference_type (basetype), parm,
	     CONV_IMPLICIT|CONV_CONST, LOOKUP_COMPLAIN, NULL_TREE);
	  p = convert_from_reference (p);
	  current_base_init_list = tree_cons (TYPE_NESTED_NAME (basetype),
					      p, current_base_init_list);
	}
      for (; fields; fields = TREE_CHAIN (fields))
	{
	  tree name, init, t;
	  tree field = fields;

	  if (TREE_CODE (field) != FIELD_DECL)
	    continue;
	  if (DECL_NAME (field))
	    {
	      if (VFIELD_NAME_P (DECL_NAME (field)))
		continue;
	      if (VBASE_NAME_P (DECL_NAME (field)))
		continue;

	      /* True for duplicate members.  */
	      if (IDENTIFIER_CLASS_VALUE (DECL_NAME (field)) != field)
		continue;
	    }
	  else if ((t = TREE_TYPE (field)) != NULL_TREE
		   && TREE_CODE (t) == UNION_TYPE
		   && ANON_AGGRNAME_P (TYPE_IDENTIFIER (t))
		   && TYPE_FIELDS (t) != NULL_TREE)
	    field = largest_union_member (t);
	  else
	    continue;

	  init = build (COMPONENT_REF, TREE_TYPE (field), parm, field);
	  init = build_tree_list (NULL_TREE, init);

	  current_member_init_list
	    = tree_cons (DECL_NAME (field), init, current_member_init_list);
	}
      current_member_init_list = nreverse (current_member_init_list);
      current_base_init_list = nreverse (current_base_init_list);
      setup_vtbl_ptr ();
    }

  pop_momentary ();
}

void
do_build_assign_ref (fndecl)
     tree fndecl;
{
  tree parm = TREE_CHAIN (DECL_ARGUMENTS (fndecl));

  clear_last_expr ();
  push_momentary ();

  parm = convert_from_reference (parm);

  if (TYPE_HAS_TRIVIAL_ASSIGN_REF (current_class_type))
    {
      tree t = build (MODIFY_EXPR, void_type_node, C_C_D, parm);
      TREE_SIDE_EFFECTS (t) = 1;
      cplus_expand_expr_stmt (t);
    }
  else
    {
      tree fields = TYPE_FIELDS (current_class_type);
      int n_bases = CLASSTYPE_N_BASECLASSES (current_class_type);
      tree binfos = TYPE_BINFO_BASETYPES (current_class_type);
      int i;

      for (i = 0; i < n_bases; ++i)
	{
	  tree basetype = BINFO_TYPE (TREE_VEC_ELT (binfos, i));
	  if (TYPE_HAS_ASSIGN_REF (basetype))
	    {
	      tree p = convert_to_reference
		(build_reference_type (basetype), parm,
		 CONV_IMPLICIT|CONV_CONST, LOOKUP_COMPLAIN, NULL_TREE);
	      p = convert_from_reference (p);
	      p = build_member_call (TYPE_NESTED_NAME (basetype),
				     ansi_opname [MODIFY_EXPR],
				     build_tree_list (NULL_TREE, p));
	      expand_expr_stmt (p);
	    }
	}
      for (; fields; fields = TREE_CHAIN (fields))
	{
	  tree comp, init, t;
	  tree field = fields;

	  if (TREE_CODE (field) != FIELD_DECL)
	    continue;
	  if (DECL_NAME (field))
	    {
	      if (VFIELD_NAME_P (DECL_NAME (field)))
		continue;
	      if (VBASE_NAME_P (DECL_NAME (field)))
		continue;

	      /* True for duplicate members.  */
	      if (IDENTIFIER_CLASS_VALUE (DECL_NAME (field)) != field)
		continue;
	    }
	  else if ((t = TREE_TYPE (field)) != NULL_TREE
		   && TREE_CODE (t) == UNION_TYPE
		   && ANON_AGGRNAME_P (TYPE_IDENTIFIER (t))
		   && TYPE_FIELDS (t) != NULL_TREE)
	    field = largest_union_member (t);
	  else
	    continue;

	  comp = build (COMPONENT_REF, TREE_TYPE (field), C_C_D, field);
	  init = build (COMPONENT_REF, TREE_TYPE (field), parm, field);

	  expand_expr_stmt (build_modify_expr (comp, NOP_EXPR, init));
	}
    }
  c_expand_return (C_C_D);
  pop_momentary ();
}

void push_cp_function_context ();
void pop_cp_function_context ();

void
synthesize_method (fndecl)
     tree fndecl;
{
  int nested = (current_function_decl != NULL_TREE);
  tree context = decl_function_context (fndecl);
  char *f = input_filename;
  tree base = DECL_CLASS_CONTEXT (fndecl);

  if (nested)
    push_cp_function_context (context);

  input_filename = DECL_SOURCE_FILE (fndecl);
  interface_unknown = CLASSTYPE_INTERFACE_UNKNOWN (base);
  interface_only = CLASSTYPE_INTERFACE_ONLY (base);
  start_function (NULL_TREE, fndecl, NULL_TREE, NULL_TREE, 1);
  store_parm_decls ();

  if (DECL_NAME (fndecl) == ansi_opname[MODIFY_EXPR])
    do_build_assign_ref (fndecl);
  else if (DESTRUCTOR_NAME_P (DECL_ASSEMBLER_NAME (fndecl)))
    ;
  else
    {
      tree arg_chain = FUNCTION_ARG_CHAIN (fndecl);
      if (DECL_CONSTRUCTOR_FOR_VBASE_P (fndecl))
	arg_chain = TREE_CHAIN (arg_chain);
      if (arg_chain != void_list_node)
	do_build_copy_constructor (fndecl);
      else if (TYPE_NEEDS_CONSTRUCTING (current_class_type))
	setup_vtbl_ptr ();
    }

  finish_function (lineno, 0, nested);

  /* Do we really *want* to inline this function?  */
  if (DECL_INLINE (fndecl))
    {
      /* Turn off DECL_INLINE for the moment so function_cannot_inline_p
         will check our size.  */
      DECL_INLINE (fndecl) = 0;
      if (function_cannot_inline_p (fndecl) == 0)
	DECL_INLINE (fndecl) = 1;
    }

  input_filename = f;
  extract_interface_info ();
  if (nested)
    pop_cp_function_context (context);
}