C++ DECL_CHAIN函数代码示例

static tree
vxworks_emutls_var_fields (tree type, tree *name)
{
  tree field, next_field;
  
  *name = get_identifier ("__tls_var");
  
  field = build_decl (BUILTINS_LOCATION, FIELD_DECL,
		      get_identifier ("size"), unsigned_type_node);
  DECL_CONTEXT (field) = type;
  next_field = field;

  field = build_decl (BUILTINS_LOCATION, FIELD_DECL,
		      get_identifier ("module_id"), unsigned_type_node);
  DECL_CONTEXT (field) = type;
  DECL_CHAIN (field) = next_field;
  next_field = field;

  field = build_decl (BUILTINS_LOCATION, FIELD_DECL,
		      get_identifier ("offset"), unsigned_type_node);
  DECL_CONTEXT (field) = type;
  DECL_CHAIN (field) = next_field;

  return field;
}

static tree
vxworks_emutls_var_init (tree var, tree decl, tree tmpl_addr)
{
  VEC(constructor_elt,gc) *v = VEC_alloc (constructor_elt, gc, 3);
  constructor_elt *elt;
  
  tree type = TREE_TYPE (var);
  tree field = TYPE_FIELDS (type);
  
  elt = VEC_quick_push (constructor_elt, v, NULL);
  elt->index = field;
  elt->value = fold_convert (TREE_TYPE (field), tmpl_addr);
  
  elt = VEC_quick_push (constructor_elt, v, NULL);
  field = DECL_CHAIN (field);
  elt->index = field;
  elt->value = build_int_cst (TREE_TYPE (field), 0);
  
  elt = VEC_quick_push (constructor_elt, v, NULL);
  field = DECL_CHAIN (field);
  elt->index = field;
  elt->value = fold_convert (TREE_TYPE (field), DECL_SIZE_UNIT (decl));
  
  return build_constructor (type, v);
}

static void
finish_bc_block (tree *block, enum bc_t bc, tree label)
{
  gcc_assert (label == bc_label[bc]);

  if (TREE_USED (label))
    append_to_statement_list (build1 (LABEL_EXPR, void_type_node, label),
			      block);

  bc_label[bc] = DECL_CHAIN (label);
  DECL_CHAIN (label) = NULL_TREE;
}

tree
ubsan_instrument_bounds (location_t loc, tree array, tree *index,
			 bool ignore_off_by_one)
{
  tree type = TREE_TYPE (array);
  tree domain = TYPE_DOMAIN (type);

  if (domain == NULL_TREE || TYPE_MAX_VALUE (domain) == NULL_TREE)
    return NULL_TREE;

  tree bound = TYPE_MAX_VALUE (domain);
  if (ignore_off_by_one)
    bound = fold_build2 (PLUS_EXPR, TREE_TYPE (bound), bound,
			 build_int_cst (TREE_TYPE (bound), 1));

  /* Detect flexible array members and suchlike.  */
  tree base = get_base_address (array);
  if (base && (TREE_CODE (base) == INDIRECT_REF
	       || TREE_CODE (base) == MEM_REF))
    {
      tree next = NULL_TREE;
      tree cref = array;

      /* Walk all structs/unions.  */
      while (TREE_CODE (cref) == COMPONENT_REF)
	{
	  if (TREE_CODE (TREE_TYPE (TREE_OPERAND (cref, 0))) == RECORD_TYPE)
	    for (next = DECL_CHAIN (TREE_OPERAND (cref, 1));
		 next && TREE_CODE (next) != FIELD_DECL;
		 next = DECL_CHAIN (next))
	      ;
	  if (next)
	    /* Not a last element.  Instrument it.  */
	    break;
	  /* Ok, this is the last field of the structure/union.  But the
	     aggregate containing the field must be the last field too,
	     recursively.  */
	  cref = TREE_OPERAND (cref, 0);
	}
      if (!next)
	/* Don't instrument this flexible array member-like array in non-strict
	   -fsanitize=bounds mode.  */
        return NULL_TREE;
    }

  *index = save_expr (*index);
  /* Create a "(T *) 0" tree node to describe the array type.  */
  tree zero_with_type = build_int_cst (build_pointer_type (type), 0);
  return build_call_expr_internal_loc (loc, IFN_UBSAN_BOUNDS,
				       void_type_node, 3, zero_with_type,
				       *index, bound);
}

static gimple_seq
finish_bc_block (enum bc_t bc, tree label, gimple_seq body)
{
  gcc_assert (label == bc_label[bc]);

  if (TREE_USED (label))
    {
      gimple_seq_add_stmt (&body, gimple_build_label (label));
    }

  bc_label[bc] = DECL_CHAIN (label);
  DECL_CHAIN (label) = NULL_TREE;
  return body;
}

tree
pushdecl (tree decl)
{
  if (global_bindings_p ())
    DECL_CONTEXT (decl) = current_translation_unit;
  else
    {
      /* External objects aren't nested.  For debug info insert a copy
         of the decl into the binding level.  */
      if (DECL_EXTERNAL (decl))
	{
	  tree orig = decl;
	  decl = copy_node (decl);
	  DECL_CONTEXT (orig) = NULL_TREE;
	}
      DECL_CONTEXT (decl) = current_function_decl;
    }

  /* Put the declaration on the list.  */
  DECL_CHAIN (decl) = current_binding_level->names;
  current_binding_level->names = decl;

  /* For the declaration of a type, set its name if it is not already set.  */

  if (TREE_CODE (decl) == TYPE_DECL && TYPE_NAME (TREE_TYPE (decl)) == 0)
    {
      if (DECL_SOURCE_LINE (decl) == 0)
	TYPE_NAME (TREE_TYPE (decl)) = decl;
      else
	TYPE_NAME (TREE_TYPE (decl)) = DECL_NAME (decl);
    }

  return decl;
}

static void
gfc_be_parse_file (void)
{
  gfc_create_decls ();
  gfc_parse_file ();
  gfc_generate_constructors ();

  /* Clear the binding level stack.  */
  while (!global_bindings_p ())
    poplevel (0, 0);

  /* Finalize all of the globals.

     Emulated tls lowering needs to see all TLS variables before we
     call finalize_compilation_unit.  The C/C++ front ends manage this
     by calling decl_rest_of_compilation on each global and static
     variable as they are seen.  The Fortran front end waits until
     here.  */
  for (tree decl = getdecls (); decl ; decl = DECL_CHAIN (decl))
    rest_of_decl_compilation (decl, true, true);

  /* Switch to the default tree diagnostics here, because there may be
     diagnostics before gfc_finish().  */
  gfc_diagnostics_finish ();

  global_decl_processing ();
}

static tree
ubsan_source_location_type (void)
{
  static const char *field_names[3]
    = { "__filename", "__line", "__column" };
  tree fields[3], ret;
  tree const_char_type = build_qualified_type (char_type_node,
					       TYPE_QUAL_CONST);

  ret = make_node (RECORD_TYPE);
  for (int i = 0; i < 3; i++)
    {
      fields[i] = build_decl (UNKNOWN_LOCATION, FIELD_DECL,
			      get_identifier (field_names[i]),
			      (i == 0) ? build_pointer_type (const_char_type)
			      : unsigned_type_node);
      DECL_CONTEXT (fields[i]) = ret;
      if (i)
	DECL_CHAIN (fields[i - 1]) = fields[i];
    }
  TYPE_FIELDS (ret) = fields[0];
  TYPE_NAME (ret) = get_identifier ("__ubsan_source_location");
  layout_type (ret);
  return ret;
}

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;
}

static void
set_block_origin_self (tree stmt)
{
  if (BLOCK_ABSTRACT_ORIGIN (stmt) == NULL_TREE)
    {
      BLOCK_ABSTRACT_ORIGIN (stmt) = stmt;

      {
	tree local_decl;

	for (local_decl = BLOCK_VARS (stmt);
	     local_decl != NULL_TREE;
	     local_decl = DECL_CHAIN (local_decl))
	  if (! DECL_EXTERNAL (local_decl))
	    set_decl_origin_self (local_decl);	/* Potential recursion.  */
      }

      {
	tree subblock;

	for (subblock = BLOCK_SUBBLOCKS (stmt);
	     subblock != NULL_TREE;
	     subblock = BLOCK_CHAIN (subblock))
	  set_block_origin_self (subblock);	/* Recurse.  */
      }
    }
}

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 tree
ubsan_type_descriptor_type (void)
{
  static const char *field_names[3]
    = { "__typekind", "__typeinfo", "__typename" };
  tree fields[3], ret;
  tree itype = build_range_type (sizetype, size_zero_node, NULL_TREE);
  tree flex_arr_type = build_array_type (char_type_node, itype);

  ret = make_node (RECORD_TYPE);
  for (int i = 0; i < 3; i++)
    {
      fields[i] = build_decl (UNKNOWN_LOCATION, FIELD_DECL,
			      get_identifier (field_names[i]),
			      (i == 2) ? flex_arr_type
			      : short_unsigned_type_node);
      DECL_CONTEXT (fields[i]) = ret;
      if (i)
	DECL_CHAIN (fields[i - 1]) = fields[i];
    }
  TYPE_FIELDS (ret) = fields[0];
  TYPE_NAME (ret) = get_identifier ("__ubsan_type_descriptor");
  layout_type (ret);
  return ret;
}

static void
set_block_abstract_flags (tree stmt, int setting)
{
  tree local_decl;
  tree subblock;
  unsigned int i;

  BLOCK_ABSTRACT (stmt) = setting;

  for (local_decl = BLOCK_VARS (stmt);
       local_decl != NULL_TREE;
       local_decl = DECL_CHAIN (local_decl))
    if (! DECL_EXTERNAL (local_decl))
      set_decl_abstract_flags (local_decl, setting);

  for (i = 0; i < BLOCK_NUM_NONLOCALIZED_VARS (stmt); i++)
    {
      local_decl = BLOCK_NONLOCALIZED_VAR (stmt, i);
      if ((TREE_CODE (local_decl) == VAR_DECL && !TREE_STATIC (local_decl))
	  || TREE_CODE (local_decl) == PARM_DECL)
	set_decl_abstract_flags (local_decl, setting);
    }

  for (subblock = BLOCK_SUBBLOCKS (stmt);
       subblock != NULL_TREE;
       subblock = BLOCK_CHAIN (subblock))
    set_block_abstract_flags (subblock, setting);
}

void
record_vars_into (tree vars, tree fn)
{
  bool change_cfun = fn != current_function_decl;

  if (change_cfun)
    push_cfun (DECL_STRUCT_FUNCTION (fn));

  for (; vars; vars = DECL_CHAIN (vars))
    {
      tree var = vars;

      /* BIND_EXPRs contains also function/type/constant declarations
         we don't need to care about.  */
      if (TREE_CODE (var) != VAR_DECL)
	continue;

      /* Nothing to do in this case.  */
      if (DECL_EXTERNAL (var))
	continue;

      /* Record the variable.  */
      add_local_decl (cfun, var);
    }

  if (change_cfun)
    pop_cfun ();
}

static tree
create_struct_type(tree decl, size_t front_rz_size, size_t rear_rz_size)
{
    // TODO make this dynamic rather than static
    char type_name[50];
    tree fieldfront, orig_var, fieldrear, struct_type;

    gcc_assert(front_rz_size % 8 == 0 && rear_rz_size % 8 == 0);

    struct_type = mf_mark(make_node (RECORD_TYPE));

    // Build the front red zone
    tree front_array_idx =  build_index_type (size_int (front_rz_size / sizeof(unsigned int)));
    tree front_rz_array = build_array_type (unsigned_type_node, front_array_idx);
    fieldfront = build_decl (UNKNOWN_LOCATION,
            FIELD_DECL, get_identifier ("rz_front"), front_rz_array);
    DECL_ALIGN(fieldfront) = 8;
    DECL_CONTEXT (fieldfront) = struct_type;

    // orig variable
    orig_var = build_decl (UNKNOWN_LOCATION,
            FIELD_DECL, get_identifier("orig_var"), TREE_TYPE(decl));
    DECL_CONTEXT (orig_var) = struct_type; // Look at comments above
    DECL_CHAIN (fieldfront) = orig_var;

    // Rear zone
    if (COMPLETE_TYPE_P(decl)){
        tree rear_array_idx =  build_index_type (size_int (rear_rz_size / sizeof(unsigned int)));
        tree rear_rz_array = build_array_type (unsigned_type_node, rear_array_idx);
        fieldrear = build_decl (UNKNOWN_LOCATION,
                FIELD_DECL, get_identifier ("rz_rear"), rear_rz_array);
        DECL_ALIGN(fieldrear) = 8;
        DECL_CONTEXT (fieldrear) = struct_type;
        DECL_CHAIN (orig_var) = fieldrear;
    }

    TYPE_FIELDS (struct_type) = fieldfront;

    strcpy(type_name, "rz_");
    strcat(type_name, get_name(decl));
    strcat(type_name, "_type");
    TYPE_NAME (struct_type) = get_identifier (type_name);
    layout_type (struct_type);

    return struct_type;
}