C++ DECL_ARGUMENTS函数代码示例

static enum in_charge_use
compute_use_thunks (tree fn)
{
  tree last_arg, fn_parm;

  if (DECL_HAS_VTT_PARM_P (fn))
    return NO_THUNKS;

  if (flag_apple_kext)
    return NO_THUNKS;

  if (flag_clone_structors)
    return NO_THUNKS;

  /* Functions that are too small will just get inlined back in anyway.
     Let the inliner do something useful instead.  */
  if (flag_inline_functions
      && estimate_num_insns (DECL_SAVED_TREE (fn)) < MAX_INLINE_INSNS_AUTO)
    return NO_THUNKS;

  /* If function accepts variable arguments, give up.  */
  last_arg = tree_last (TYPE_ARG_TYPES (TREE_TYPE (fn)));
  if ( ! VOID_TYPE_P (TREE_VALUE (last_arg)))
       return NO_THUNKS;

  /* If constructor expects vector (AltiVec) arguments, give up.  */
  for (fn_parm = DECL_ARGUMENTS (fn); fn_parm; fn_parm = TREE_CHAIN (fn_parm))
    if (TREE_CODE (fn_parm) == VECTOR_TYPE)
      return NO_THUNKS;

  if (DECL_HAS_IN_CHARGE_PARM_P (fn))
    {
      int parmno;
      struct thunk_tree_walk_data data;
      for (parmno = 0, fn_parm = DECL_ARGUMENTS (fn);
	   fn_parm;
	   ++parmno, fn_parm = TREE_CHAIN (fn_parm))
	if (parmno == 1)
	  {
	    data.in_charge_parm = fn_parm;
	    break;
	  }
      /* If every use of the in-charge parameter ANDs it
	 with 1, then the functions that have in-charge
	 set to 1 and 3 are equivalent, likewise 0 and 2.
	 Check for this (common in practice).  Likewise,
	 if every use tests for equality with 0, then
	 values 1, 2 and 3 are equivalent.  */
      gcc_assert (data.in_charge_parm != NULL_TREE);
      data.in_charge_use = ALL_THUNKS;
      walk_tree_without_duplicates (&DECL_SAVED_TREE (fn), 
				    examine_tree_for_in_charge_use, 
				    &data);
      return data.in_charge_use;
    }

  return ALL_THUNKS;
}

static bool
suitable_for_tail_call_opt_p (void)
{
  tree param;

  /* alloca (until we have stack slot life analysis) inhibits
     sibling call optimizations, but not tail recursion.  */
  if (cfun->calls_alloca)
    return false;

  /* If we are using sjlj exceptions, we may need to add a call to
     _Unwind_SjLj_Unregister at exit of the function.  Which means
     that we cannot do any sibcall transformations.  */
  if (targetm_common.except_unwind_info (&global_options) == UI_SJLJ
      && current_function_has_exception_handlers ())
    return false;

  /* Any function that calls setjmp might have longjmp called from
     any called function.  ??? We really should represent this
     properly in the CFG so that this needn't be special cased.  */
  if (cfun->calls_setjmp)
    return false;

  /* ??? It is OK if the argument of a function is taken in some cases,
     but not in all cases.  See PR15387 and PR19616.  Revisit for 4.1.  */
  for (param = DECL_ARGUMENTS (current_function_decl);
       param;
       param = DECL_CHAIN (param))
    if (TREE_ADDRESSABLE (param))
      return false;

  return true;
}

void
pp_c_parameter_type_list (c_pretty_printer *pp, tree t)
{
  bool want_parm_decl = DECL_P (t) && !(pp->flags & pp_c_flag_abstract);
  tree parms = want_parm_decl ? DECL_ARGUMENTS (t) :  TYPE_ARG_TYPES (t);
  pp_c_left_paren (pp);
  if (parms == void_list_node)
    pp_c_identifier (pp, "void");
  else
    {
      bool first = true;
      for ( ; parms && parms != void_list_node; parms = TREE_CHAIN (parms))
	{
	  if (!first)
	    pp_separate_with (pp, ',');
	  first = false;
	  pp_declaration_specifiers
	    (pp, want_parm_decl ? parms : TREE_VALUE (parms));
	  if (want_parm_decl)
	    pp_declarator (pp, parms);
	  else
	    pp_abstract_declarator (pp, TREE_VALUE (parms));
	}
    }
  pp_c_right_paren (pp);
}

tree
build_capture_proxy (tree member)
{
  tree var, object, fn, closure, name, lam, type;

  if (PACK_EXPANSION_P (member))
    member = PACK_EXPANSION_PATTERN (member);

  closure = DECL_CONTEXT (member);
  fn = lambda_function (closure);
  lam = CLASSTYPE_LAMBDA_EXPR (closure);

  /* The proxy variable forwards to the capture field.  */
  object = build_fold_indirect_ref (DECL_ARGUMENTS (fn));
  object = finish_non_static_data_member (member, object, NULL_TREE);
  if (REFERENCE_REF_P (object))
    object = TREE_OPERAND (object, 0);

  /* Remove the __ inserted by add_capture.  */
  if (DECL_NORMAL_CAPTURE_P (member))
    name = get_identifier (IDENTIFIER_POINTER (DECL_NAME (member)) + 2);
  else
    name = DECL_NAME (member);

  type = lambda_proxy_type (object);

  if (DECL_VLA_CAPTURE_P (member))
    {
      /* Rebuild the VLA type from the pointer and maxindex.  */
      tree field = next_initializable_field (TYPE_FIELDS (type));
      tree ptr = build_simple_component_ref (object, field);
      field = next_initializable_field (DECL_CHAIN (field));
      tree max = build_simple_component_ref (object, field);
      type = build_cplus_array_type (TREE_TYPE (TREE_TYPE (ptr)),
				     build_index_type (max));
      type = build_reference_type (type);
      REFERENCE_VLA_OK (type) = true;
      object = convert (type, ptr);
    }

  var = build_decl (input_location, VAR_DECL, name, type);
  SET_DECL_VALUE_EXPR (var, object);
  DECL_HAS_VALUE_EXPR_P (var) = 1;
  DECL_ARTIFICIAL (var) = 1;
  TREE_USED (var) = 1;
  DECL_CONTEXT (var) = fn;

  if (name == this_identifier)
    {
      gcc_assert (LAMBDA_EXPR_THIS_CAPTURE (lam) == member);
      LAMBDA_EXPR_THIS_CAPTURE (lam) = var;
    }

  if (fn == current_function_decl)
    insert_capture_proxy (var);
  else
    vec_safe_push (LAMBDA_EXPR_PENDING_PROXIES (lam), var);

  return var;
}

static bool
needs_frame_header_p (function *fn)
{
  tree t;

  if (fn->decl == NULL)
    return true;

  if (fn->stdarg)
    return true;

  for (t = DECL_ARGUMENTS (fn->decl); t; t = TREE_CHAIN (t))
    {
      if (!use_register_for_decl (t))
	return true;

      /* Some 64-bit types may get copied to general registers using the frame
	 header, see mips_output_64bit_xfer.  Checking for SImode only may be
         overly restrictive but it is guaranteed to be safe. */
      if (DECL_MODE (t) != SImode)
	return true;
    }

  return false;
}

static void
init_parameter_lattice_values (void)
{
  tree parm, ssa_name;

  for (parm = DECL_ARGUMENTS (cfun->decl); parm ; parm = DECL_CHAIN (parm))
    if (is_complex_reg (parm)
	&& (ssa_name = ssa_default_def (cfun, parm)) != NULL_TREE)
      complex_lattice_values[SSA_NAME_VERSION (ssa_name)] = VARYING;
}

static void
write_ts_decl_non_common_tree_pointers (struct output_block *ob, tree expr,
				        bool ref_p)
{
  if (TREE_CODE (expr) == FUNCTION_DECL)
    {
      stream_write_tree (ob, DECL_ARGUMENTS (expr), ref_p);
      stream_write_tree (ob, DECL_RESULT (expr), ref_p);
    }
  stream_write_tree (ob, DECL_VINDEX (expr), ref_p);
}

unsigned int find_arg_number_tree(const_tree arg, const_tree func)
{
	tree var;
	unsigned int argnum = 1;

	if (DECL_ARGUMENTS(func) == NULL_TREE)
		return CANNOT_FIND_ARG;

	if (TREE_CODE(arg) == SSA_NAME)
		arg = SSA_NAME_VAR(arg);

	for (var = DECL_ARGUMENTS(func); var; var = TREE_CHAIN(var), argnum++) {
		if (!operand_equal_p(arg, var, 0) && strcmp(DECL_NAME_POINTER(var), DECL_NAME_POINTER(arg)))
			continue;
		if (!skip_types(var))
			return argnum;
	}

	return CANNOT_FIND_ARG;
}

static void
init_parameter_lattice_values (void)
{
  tree parm, ssa_name;

  for (parm = DECL_ARGUMENTS (cfun->decl); parm ; parm = TREE_CHAIN (parm))
    if (is_complex_reg (parm)
	&& var_ann (parm) != NULL
	&& (ssa_name = gimple_default_def (cfun, parm)) != NULL_TREE)
      VEC_replace (complex_lattice_t, complex_lattice_values,
		   SSA_NAME_VERSION (ssa_name), VARYING);
}

tree
make_alias_for (tree target, tree newid)
{
  tree alias = build_decl (DECL_SOURCE_LOCATION (target),
			   TREE_CODE (target), newid, TREE_TYPE (target));
  DECL_LANG_SPECIFIC (alias) = DECL_LANG_SPECIFIC (target);
  cxx_dup_lang_specific_decl (alias);
  DECL_CONTEXT (alias) = NULL;
  TREE_READONLY (alias) = TREE_READONLY (target);
  TREE_THIS_VOLATILE (alias) = TREE_THIS_VOLATILE (target);
  TREE_PUBLIC (alias) = 0;
  DECL_INTERFACE_KNOWN (alias) = 1;
  if (DECL_LANG_SPECIFIC (alias))
    {
      DECL_NOT_REALLY_EXTERN (alias) = 1;
      DECL_USE_TEMPLATE (alias) = 0;
      DECL_TEMPLATE_INFO (alias) = NULL;
    }
  DECL_EXTERNAL (alias) = 0;
  DECL_ARTIFICIAL (alias) = 1;
  DECL_TEMPLATE_INSTANTIATED (alias) = 0;
  if (TREE_CODE (alias) == FUNCTION_DECL)
    {
      DECL_SAVED_FUNCTION_DATA (alias) = NULL;
      DECL_DESTRUCTOR_P (alias) = 0;
      DECL_CONSTRUCTOR_P (alias) = 0;
      DECL_PENDING_INLINE_P (alias) = 0;
      DECL_DECLARED_INLINE_P (alias) = 0;
      DECL_INITIAL (alias) = error_mark_node;
      DECL_ARGUMENTS (alias) = copy_list (DECL_ARGUMENTS (target));
    }
  else
    TREE_STATIC (alias) = 1;
  TREE_ADDRESSABLE (alias) = 1;
  TREE_USED (alias) = 1;
  SET_DECL_ASSEMBLER_NAME (alias, DECL_NAME (alias));
  TREE_SYMBOL_REFERENCED (DECL_ASSEMBLER_NAME (alias)) = 1;
  return alias;
}

static void
lto_input_ts_decl_non_common_tree_pointers (struct lto_input_block *ib,
					    struct data_in *data_in, tree expr)
{
  if (TREE_CODE (expr) == FUNCTION_DECL)
    {
      DECL_ARGUMENTS (expr) = stream_read_tree (ib, data_in);
      DECL_RESULT (expr) = stream_read_tree (ib, data_in);
    }
  else if (TREE_CODE (expr) == TYPE_DECL)
    DECL_ORIGINAL_TYPE (expr) = stream_read_tree (ib, data_in);
  DECL_VINDEX (expr) = stream_read_tree (ib, data_in);
}

void
xcoffout_begin_block (unsigned int line, unsigned int n)
{
  tree decl = current_function_decl;

  /* The IBM AIX compiler does not emit a .bb for the function level scope,
     so we avoid it here also.  */
  if (n != 1)
    ASM_OUTPUT_LBB (asm_out_file, line, n);

  do_block = n;
  xcoffout_block (DECL_INITIAL (decl), 0, DECL_ARGUMENTS (decl));
}

void
set_decl_abstract_flags (tree decl, int setting)
{
  DECL_ABSTRACT (decl) = setting;
  if (TREE_CODE (decl) == FUNCTION_DECL)
    {
      tree arg;

      for (arg = DECL_ARGUMENTS (decl); arg; arg = DECL_CHAIN (arg))
	DECL_ABSTRACT (arg) = setting;
      if (DECL_INITIAL (decl) != NULL_TREE
	  && DECL_INITIAL (decl) != error_mark_node)
	set_block_abstract_flags (DECL_INITIAL (decl), setting);
    }
}

void
cp_genericize (tree fndecl)
{
  tree t;
  struct pointer_set_t *p_set;

  /* Fix up the types of parms passed by invisible reference.  */
  for (t = DECL_ARGUMENTS (fndecl); t; t = TREE_CHAIN (t))
    if (TREE_ADDRESSABLE (TREE_TYPE (t)))
      {
	/* If a function's arguments are copied to create a thunk,
	   then DECL_BY_REFERENCE will be set -- but the type of the
	   argument will be a pointer type, so we will never get
	   here.  */
	gcc_assert (!DECL_BY_REFERENCE (t));
	gcc_assert (DECL_ARG_TYPE (t) != TREE_TYPE (t));
	TREE_TYPE (t) = DECL_ARG_TYPE (t);
	DECL_BY_REFERENCE (t) = 1;
	TREE_ADDRESSABLE (t) = 0;
	relayout_decl (t);
      }

  /* Do the same for the return value.  */
  if (TREE_ADDRESSABLE (TREE_TYPE (DECL_RESULT (fndecl))))
    {
      t = DECL_RESULT (fndecl);
      TREE_TYPE (t) = build_reference_type (TREE_TYPE (t));
      DECL_BY_REFERENCE (t) = 1;
      TREE_ADDRESSABLE (t) = 0;
      relayout_decl (t);
    }

  /* If we're a clone, the body is already GIMPLE.  */
  if (DECL_CLONED_FUNCTION_P (fndecl))
    return;

  /* We do want to see every occurrence of the parms, so we can't just use
     walk_tree's hash functionality.  */
  p_set = pointer_set_create ();
  cp_walk_tree (&DECL_SAVED_TREE (fndecl), cp_genericize_r, p_set, NULL);
  pointer_set_destroy (p_set);

  /* Do everything else.  */
  c_genericize (fndecl);

  gcc_assert (bc_label[bc_break] == NULL);
  gcc_assert (bc_label[bc_continue] == NULL);
}

static void
execute_mudflap_function_decls (void)
{
  /* Don't instrument functions such as the synthetic constructor
     built during mudflap_finish_file.  */
  if (mf_marked_p (current_function_decl) ||
      DECL_ARTIFICIAL (current_function_decl))
    return;

  push_gimplify_context ();

  mf_xform_decls (DECL_SAVED_TREE (current_function_decl),
                  DECL_ARGUMENTS (current_function_decl));

  pop_gimplify_context (NULL);
}