C++ DECL_SIZE函数代码示例

/* Output a declaration.  Used for function locals, and struct/union members. */
void xml_generic_decl(tree decl, int indent, const char *tag, FILE *out)
{
    fprintf(out, "%s<%s", spc(indent), tag);
    xml_location(decl, out);
    fprintf(out, ">\n");
    indent += INDENT;

    xml_decl_binding(decl, indent, "binding", out);

    fprintf(out, "%s<type", spc(indent));
    if (DECL_SIZE(decl))
        fprintf(out, " size='%lu'", TREE_INT_CST_LOW(DECL_SIZE(decl)));
    if (DECL_ALIGN(decl))
        fprintf(out, " alignment='%d'", DECL_ALIGN(decl));
    fprintf(out, ">\n");

    /* Output the type. */
    xml_type(TREE_TYPE(decl), decl, indent + INDENT, out);

    fprintf(out, "%s</type>\n", spc(indent));

    if (TREE_CODE(decl) == VAR_DECL && DECL_INITIAL(decl))
    {
        fprintf(out, "%s<initial>\n", spc(indent));
        xml_expr(DECL_INITIAL(decl), indent + INDENT, out);
        fprintf(out, "%s</initial>\n", spc(indent));
    }

    indent -= INDENT;
    fprintf(out, "%s</%s>\n", spc(indent), tag);
}

static void
write_ts_decl_common_tree_pointers (struct output_block *ob, tree expr,
				    bool ref_p)
{
  stream_write_tree (ob, DECL_SIZE (expr), ref_p);
  stream_write_tree (ob, DECL_SIZE_UNIT (expr), ref_p);

  /* Note, DECL_INITIAL is not handled here.  Since DECL_INITIAL needs
     special handling in LTO, it must be handled by streamer hooks.  */

  stream_write_tree (ob, DECL_ATTRIBUTES (expr), ref_p);

  /* Do not stream DECL_ABSTRACT_ORIGIN.  We cannot handle debug information
     for early inlining so drop it on the floor instead of ICEing in
     dwarf2out.c.  */

  if (TREE_CODE (expr) == PARM_DECL)
    streamer_write_chain (ob, TREE_CHAIN (expr), ref_p);

  if ((TREE_CODE (expr) == VAR_DECL
       || TREE_CODE (expr) == PARM_DECL)
      && DECL_HAS_VALUE_EXPR_P (expr))
    stream_write_tree (ob, DECL_VALUE_EXPR (expr), ref_p);

  if (TREE_CODE (expr) == VAR_DECL)
    stream_write_tree (ob, DECL_DEBUG_EXPR (expr), ref_p);
}

static void
lto_input_ts_decl_common_tree_pointers (struct lto_input_block *ib,
					struct data_in *data_in, tree expr)
{
  DECL_SIZE (expr) = stream_read_tree (ib, data_in);
  DECL_SIZE_UNIT (expr) = stream_read_tree (ib, data_in);
  DECL_ATTRIBUTES (expr) = stream_read_tree (ib, data_in);

  /* Do not stream DECL_ABSTRACT_ORIGIN.  We cannot handle debug information
     for early inlining so drop it on the floor instead of ICEing in
     dwarf2out.c.  */

  if (TREE_CODE (expr) == PARM_DECL)
    TREE_CHAIN (expr) = streamer_read_chain (ib, data_in);

  if ((TREE_CODE (expr) == VAR_DECL
       || TREE_CODE (expr) == PARM_DECL)
      && DECL_HAS_VALUE_EXPR_P (expr))
    SET_DECL_VALUE_EXPR (expr, stream_read_tree (ib, data_in));

  if (TREE_CODE (expr) == VAR_DECL)
    {
      tree dexpr = stream_read_tree (ib, data_in);
      if (dexpr)
	SET_DECL_DEBUG_EXPR (expr, dexpr);
    }
}

struct FieldInfo* createFieldInfo(const tree field_decl)
{
  struct FieldInfo* fi = (struct FieldInfo*) xcalloc(1, sizeof(struct FieldInfo));
  fi->isSpecial = DECL_ARTIFICIAL(field_decl);
  fi->isBitField = DECL_BIT_FIELD(field_decl);

  const char* fieldName;
  if (fi->isSpecial)
    fieldName = fieldNames[FIELD_BASE];
  else if (DECL_NAME(field_decl))
    fieldName = IDENTIFIER_POINTER(DECL_NAME(field_decl));
  else
    fieldName = fieldNames[FIELD_NONAME];

  fi->name = xstrdup(fieldName);

  fi->size = TREE_INT_CST_LOW(DECL_SIZE(field_decl));

  // Offset calculation is a little bit wierd. According to GCC docs:
  // "... DECL_FIELD_OFFSET is position, counting in bytes, of the
  // DECL_OFFSET_ALIGN-bit sized word ..." and ".. DECL_FIELD_BIT_OFFSET is the
  // bit offset of the first bit of the field within this word"
  fi->offset = TREE_INT_CST_LOW(DECL_FIELD_OFFSET(field_decl)) * BITS_PER_UNIT +
    TREE_INT_CST_LOW(DECL_FIELD_BIT_OFFSET(field_decl));

  fi->align = DECL_ALIGN(field_decl);

  return fi;
}

static void
sdbout_field_types (tree type)
{
  tree tail;

  for (tail = TYPE_FIELDS (type); tail; tail = TREE_CHAIN (tail))
    /* This condition should match the one for emitting the actual
       members below.  */
    if (TREE_CODE (tail) == FIELD_DECL
	&& DECL_NAME (tail)
	&& DECL_SIZE (tail)
	&& host_integerp (DECL_SIZE (tail), 1)
	&& host_integerp (bit_position (tail), 0))
      {
	if (POINTER_TYPE_P (TREE_TYPE (tail)))
	  sdbout_one_type (TREE_TYPE (TREE_TYPE (tail)));
	else
	  sdbout_one_type (TREE_TYPE (tail));
      }
}

static tree
ubsan_walk_array_refs_r (tree *tp, int *walk_subtrees, void *data)
{
  hash_set<tree> *pset = (hash_set<tree> *) data;

  if (TREE_CODE (*tp) == BIND_EXPR)
    {
      /* Since walk_tree doesn't call the callback function on the decls
	 in BIND_EXPR_VARS, we have to walk them manually, so we can avoid
	 instrumenting DECL_INITIAL of TREE_STATIC vars.  */
      *walk_subtrees = 0;
      for (tree decl = BIND_EXPR_VARS (*tp); decl; decl = DECL_CHAIN (decl))
	{
	  if (TREE_STATIC (decl))
	    continue;
	  walk_tree (&DECL_INITIAL (decl), ubsan_walk_array_refs_r, pset,
		     pset);
	  walk_tree (&DECL_SIZE (decl), ubsan_walk_array_refs_r, pset, pset);
	  walk_tree (&DECL_SIZE_UNIT (decl), ubsan_walk_array_refs_r, pset,
		     pset);
	}
      walk_tree (&BIND_EXPR_BODY (*tp), ubsan_walk_array_refs_r, pset, pset);
    }
  else if (TREE_CODE (*tp) == ADDR_EXPR
	   && TREE_CODE (TREE_OPERAND (*tp, 0)) == ARRAY_REF)
    {
      ubsan_maybe_instrument_array_ref (&TREE_OPERAND (*tp, 0), true);
      /* Make sure ubsan_maybe_instrument_array_ref is not called again
	 on the ARRAY_REF, the above call might not instrument anything
	 as the index might be constant or masked, so ensure it is not
	 walked again and walk its subtrees manually.  */
      tree aref = TREE_OPERAND (*tp, 0);
      pset->add (aref);
      *walk_subtrees = 0;
      walk_tree (&TREE_OPERAND (aref, 0), ubsan_walk_array_refs_r, pset, pset);
      walk_tree (&TREE_OPERAND (aref, 1), ubsan_walk_array_refs_r, pset, pset);
      walk_tree (&TREE_OPERAND (aref, 2), ubsan_walk_array_refs_r, pset, pset);
      walk_tree (&TREE_OPERAND (aref, 3), ubsan_walk_array_refs_r, pset, pset);
    }
  else if (TREE_CODE (*tp) == ARRAY_REF)
    ubsan_maybe_instrument_array_ref (tp, false);
  return NULL_TREE;
}

//.........这里部分代码省略.........
      dump_child ("elts", TREE_TYPE (t));
      dump_child ("domn", TYPE_DOMAIN (t));
      break;

    case RECORD_TYPE:
    case UNION_TYPE:
      if (TREE_CODE (t) == RECORD_TYPE)
	dump_string_field (di, "tag", "struct");
      else
	dump_string_field (di, "tag", "union");

      dump_child ("flds", TYPE_FIELDS (t));
      dump_child ("fncs", TYPE_METHODS (t));
      queue_and_dump_index (di, "binf", TYPE_BINFO (t),
			    DUMP_BINFO);
      break;

    case CONST_DECL:
      dump_child ("cnst", DECL_INITIAL (t));
      break;

    case DEBUG_EXPR_DECL:
      dump_int (di, "-uid", DEBUG_TEMP_UID (t));
      /* Fall through.  */

    case VAR_DECL:
    case PARM_DECL:
    case FIELD_DECL:
    case RESULT_DECL:
      if (TREE_CODE (t) == PARM_DECL)
	dump_child ("argt", DECL_ARG_TYPE (t));
      else
	dump_child ("init", DECL_INITIAL (t));
      dump_child ("size", DECL_SIZE (t));
      dump_int (di, "algn", DECL_ALIGN (t));

      if (TREE_CODE (t) == FIELD_DECL)
	{
	  if (DECL_FIELD_OFFSET (t))
	    dump_child ("bpos", bit_position (t));
	}
      else if (TREE_CODE (t) == VAR_DECL
	       || TREE_CODE (t) == PARM_DECL)
	{
	  dump_int (di, "used", TREE_USED (t));
	  if (DECL_REGISTER (t))
	    dump_string_field (di, "spec", "register");
	}
      break;

    case FUNCTION_DECL:
      dump_child ("args", DECL_ARGUMENTS (t));
      if (DECL_EXTERNAL (t))
	dump_string_field (di, "body", "undefined");
      if (TREE_PUBLIC (t))
	dump_string_field (di, "link", "extern");
      else
	dump_string_field (di, "link", "static");
      if (DECL_SAVED_TREE (t) && !dump_flag (di, TDF_SLIM, t))
	dump_child ("body", DECL_SAVED_TREE (t));
      break;

    case INTEGER_CST:
      if (TREE_INT_CST_HIGH (t))
	dump_int (di, "high", TREE_INT_CST_HIGH (t));
      dump_int (di, "low", TREE_INT_CST_LOW (t));

//.........这里部分代码省略.........
	    TB_SET_HEAD (DECL_ATTRIBUTES (head));
	  else if (head && TYPE_P (head))
	    TB_SET_HEAD (TYPE_ATTRIBUTES (head));
	  else
	    TB_WF;
	  break;

	case TB_CONTEXT:
	  if (head && DECL_P (head))
	    TB_SET_HEAD (DECL_CONTEXT (head));
	  else if (head && TYPE_P (head)
		   && TYPE_CONTEXT (head))
	    TB_SET_HEAD (TYPE_CONTEXT (head));
	  else
	    TB_WF;
	  break;

	case TB_OFFSET:
	  if (head && TREE_CODE (head) == FIELD_DECL)
	    TB_SET_HEAD (DECL_FIELD_OFFSET (head));
	  else
	    TB_WF;
	  break;

	case TB_BIT_OFFSET:
	  if (head && TREE_CODE (head) == FIELD_DECL)
	    TB_SET_HEAD (DECL_FIELD_BIT_OFFSET (head));
	  else
	    TB_WF;
          break;

	case TB_UNIT_SIZE:
	  if (head && DECL_P (head))
	    TB_SET_HEAD (DECL_SIZE_UNIT (head));
	  else if (head && TYPE_P (head))
	    TB_SET_HEAD (TYPE_SIZE_UNIT (head));
	  else
	    TB_WF;
	  break;

	case TB_SIZE:
	  if (head && DECL_P (head))
	    TB_SET_HEAD (DECL_SIZE (head));
	  else if (head && TYPE_P (head))
	    TB_SET_HEAD (TYPE_SIZE (head));
	  else
	    TB_WF;
	  break;

	case TB_TYPE:
	  if (head && TREE_TYPE (head))
	    TB_SET_HEAD (TREE_TYPE (head));
	  else
	    TB_WF;
	  break;

	case TB_DECL_SAVED_TREE:
	  if (head && TREE_CODE (head) == FUNCTION_DECL
	      && DECL_SAVED_TREE (head))
	    TB_SET_HEAD (DECL_SAVED_TREE (head));
	  else
	    TB_WF;
	  break;

	case TB_BODY:
	  if (head && TREE_CODE (head) == BIND_EXPR)

/* Return 1 if check CI against BOUNDS always pass,
   -1 if check CI against BOUNDS always fails and
   0 if we cannot compute check result.  */
static int
chkp_get_check_result (struct check_info *ci, tree bounds)
{
    gimple *bnd_def;
    address_t bound_val;
    int sign, res = 0;

    if (dump_file && (dump_flags & TDF_DETAILS))
    {
        fprintf (dump_file, "Trying to compute result of the check\n");
        fprintf (dump_file, "  check: ");
        print_gimple_stmt (dump_file, ci->stmt, 0, 0);
        fprintf (dump_file, "  address: ");
        chkp_print_addr (ci->addr);
        fprintf (dump_file, "\n  bounds: ");
        print_generic_expr (dump_file, bounds, 0);
        fprintf (dump_file, "\n");
    }

    if (TREE_CODE (bounds) != SSA_NAME)
    {
        if (dump_file && (dump_flags & TDF_DETAILS))
            fprintf (dump_file, "  result: bounds tree code is not ssa_name\n");
        return 0;
    }

    bnd_def = SSA_NAME_DEF_STMT (bounds);
    /* Currently we handle cases when bounds are result of bndmk
       or loaded static bounds var.  */
    if (gimple_code (bnd_def) == GIMPLE_CALL
            && gimple_call_fndecl (bnd_def) == chkp_bndmk_fndecl)
    {
        bound_val.pol.create (0);
        chkp_collect_value (gimple_call_arg (bnd_def, 0), bound_val);
        if (ci->type == CHECK_UPPER_BOUND)
        {
            address_t size_val;
            size_val.pol.create (0);
            chkp_collect_value (gimple_call_arg (bnd_def, 1), size_val);
            chkp_add_addr_addr (bound_val, size_val);
            size_val.pol.release ();
            chkp_add_addr_item (bound_val, integer_minus_one_node, NULL);
        }
    }
    else if (gimple_code (bnd_def) == GIMPLE_ASSIGN
             && gimple_assign_rhs1 (bnd_def) == chkp_get_zero_bounds_var ())
    {
        if (dump_file && (dump_flags & TDF_DETAILS))
            fprintf (dump_file, "  result: always pass with zero bounds\n");
        return 1;
    }
    else if (gimple_code (bnd_def) == GIMPLE_ASSIGN
             && gimple_assign_rhs1 (bnd_def) == chkp_get_none_bounds_var ())
    {
        if (dump_file && (dump_flags & TDF_DETAILS))
            fprintf (dump_file, "  result: always fails with none bounds\n");
        return -1;
    }
    else if (gimple_code (bnd_def) == GIMPLE_ASSIGN
             && TREE_CODE (gimple_assign_rhs1 (bnd_def)) == VAR_DECL)
    {
        tree bnd_var = gimple_assign_rhs1 (bnd_def);
        tree var;
        tree size;

        if (!DECL_INITIAL (bnd_var)
                || DECL_INITIAL (bnd_var) == error_mark_node)
        {
            if (dump_file && (dump_flags & TDF_DETAILS))
                fprintf (dump_file, "  result: cannot compute bounds\n");
            return 0;
        }

        gcc_assert (TREE_CODE (DECL_INITIAL (bnd_var)) == ADDR_EXPR);
        var = TREE_OPERAND (DECL_INITIAL (bnd_var), 0);

        bound_val.pol.create (0);
        chkp_collect_value (DECL_INITIAL (bnd_var), bound_val);
        if (ci->type == CHECK_UPPER_BOUND)
        {
            if (TREE_CODE (var) == VAR_DECL)
            {
                if (DECL_SIZE (var)
                        && !chkp_variable_size_type (TREE_TYPE (var)))
                    size = DECL_SIZE_UNIT (var);
                else
                {
                    if (dump_file && (dump_flags & TDF_DETAILS))
                        fprintf (dump_file, "  result: cannot compute bounds\n");
                    return 0;
                }
            }
            else
            {
                gcc_assert (TREE_CODE (var) == STRING_CST);
                size = build_int_cst (size_type_node,
                                      TREE_STRING_LENGTH (var));
//.........这里部分代码省略.........

static symtab_node
lto_symtab_resolve_symbols (symtab_node first)
{
  symtab_node e;
  symtab_node prevailing = NULL;

  /* Always set e->node so that edges are updated to reflect decl merging. */
  for (e = first; e; e = e->symbol.next_sharing_asm_name)
    if (lto_symtab_symbol_p (e)
	&& (e->symbol.resolution == LDPR_PREVAILING_DEF_IRONLY
	    || e->symbol.resolution == LDPR_PREVAILING_DEF_IRONLY_EXP
	    || e->symbol.resolution == LDPR_PREVAILING_DEF))
      {
	prevailing = e;
	break;
      }

  /* If the chain is already resolved there is nothing else to do.  */
  if (prevailing)
    {
      /* Assert it's the only one.  */
      for (e = prevailing->symbol.next_sharing_asm_name; e; e = e->symbol.next_sharing_asm_name)
	if (lto_symtab_symbol_p (e)
	    && (e->symbol.resolution == LDPR_PREVAILING_DEF_IRONLY
		|| e->symbol.resolution == LDPR_PREVAILING_DEF_IRONLY_EXP
		|| e->symbol.resolution == LDPR_PREVAILING_DEF))
	  fatal_error ("multiple prevailing defs for %qE",
		       DECL_NAME (prevailing->symbol.decl));
      return prevailing;
    }

  /* Find the single non-replaceable prevailing symbol and
     diagnose ODR violations.  */
  for (e = first; e; e = e->symbol.next_sharing_asm_name)
    {
      if (!lto_symtab_resolve_can_prevail_p (e))
	continue;

      /* If we have a non-replaceable definition it prevails.  */
      if (!lto_symtab_resolve_replaceable_p (e))
	{
	  if (prevailing)
	    {
	      error_at (DECL_SOURCE_LOCATION (e->symbol.decl),
			"%qD has already been defined", e->symbol.decl);
	      inform (DECL_SOURCE_LOCATION (prevailing->symbol.decl),
		      "previously defined here");
	    }
	  prevailing = e;
	}
    }
  if (prevailing)
    return prevailing;

  /* Do a second round choosing one from the replaceable prevailing decls.  */
  for (e = first; e; e = e->symbol.next_sharing_asm_name)
    {
      if (!lto_symtab_resolve_can_prevail_p (e))
	continue;

      /* Choose the first function that can prevail as prevailing.  */
      if (TREE_CODE (e->symbol.decl) == FUNCTION_DECL)
	{
	  prevailing = e;
	  break;
	}

      /* From variables that can prevail choose the largest one.  */
      if (!prevailing
	  || tree_int_cst_lt (DECL_SIZE (prevailing->symbol.decl),
			      DECL_SIZE (e->symbol.decl))
	  /* When variables are equivalent try to chose one that has useful
	     DECL_INITIAL.  This makes sense for keyed vtables that are
	     DECL_EXTERNAL but initialized.  In units that do not need them
	     we replace the initializer by error_mark_node to conserve
	     memory.

	     We know that the vtable is keyed outside the LTO unit - otherwise
	     the keyed instance would prevail.  We still can preserve useful
	     info in the initializer.  */
	  || (DECL_SIZE (prevailing->symbol.decl) == DECL_SIZE (e->symbol.decl)
	      && (DECL_INITIAL (e->symbol.decl)
		  && DECL_INITIAL (e->symbol.decl) != error_mark_node)
	      && (!DECL_INITIAL (prevailing->symbol.decl)
		  || DECL_INITIAL (prevailing->symbol.decl) == error_mark_node)))
	prevailing = e;
    }

  return prevailing;
}

//.........这里部分代码省略.........
	      fn_ptr_tmp = TREE_TYPE (*anode);
	      anode = &fn_ptr_tmp;
	      flags &= ~(int) ATTR_FLAG_TYPE_IN_PLACE;
	    }
	  else if (flags & (int) ATTR_FLAG_FUNCTION_NEXT)
	    {
	      /* Pass on this attribute to be tried again.  */
	      returned_attrs = tree_cons (name, args, returned_attrs);
	      continue;
	    }

	  if (TREE_CODE (*anode) != FUNCTION_TYPE
	      && TREE_CODE (*anode) != METHOD_TYPE)
	    {
	      warning ("%qs attribute only applies to function types",
		       IDENTIFIER_POINTER (name));
	      continue;
	    }
	}

      if (spec->handler != NULL)
	returned_attrs = chainon ((*spec->handler) (anode, name, args,
						    flags, &no_add_attrs),
				  returned_attrs);

      /* Layout the decl in case anything changed.  */
      if (spec->type_required && DECL_P (*node)
	  && (TREE_CODE (*node) == VAR_DECL
	      || TREE_CODE (*node) == PARM_DECL
	      || TREE_CODE (*node) == RESULT_DECL))
	{
	  /* Force a recalculation of mode and size.  */
	  DECL_MODE (*node) = VOIDmode;
	  DECL_SIZE (*node) = 0;

	  layout_decl (*node, 0);
	}

      if (!no_add_attrs)
	{
	  tree old_attrs;
	  tree a;

	  if (DECL_P (*anode))
	    old_attrs = DECL_ATTRIBUTES (*anode);
	  else
	    old_attrs = TYPE_ATTRIBUTES (*anode);

	  for (a = lookup_attribute (spec->name, old_attrs);
	       a != NULL_TREE;
	       a = lookup_attribute (spec->name, TREE_CHAIN (a)))
	    {
	      if (simple_cst_equal (TREE_VALUE (a), args) == 1)
		break;
	    }

	  if (a == NULL_TREE)
	    {
	      /* This attribute isn't already in the list.  */
	      if (DECL_P (*anode))
		DECL_ATTRIBUTES (*anode) = tree_cons (name, args, old_attrs);
	      else if (flags & (int) ATTR_FLAG_TYPE_IN_PLACE)
		{
		  TYPE_ATTRIBUTES (*anode) = tree_cons (name, args, old_attrs);
		  /* If this is the main variant, also push the attributes
		     out to the other variants.  */

static bool
lto_symtab_merge (symtab_node *prevailing, symtab_node *entry)
{
  tree prevailing_decl = prevailing->decl;
  tree decl = entry->decl;

  if (prevailing_decl == decl)
    return true;

  /* Merge decl state in both directions, we may still end up using
     the new decl.  */
  TREE_ADDRESSABLE (prevailing_decl) |= TREE_ADDRESSABLE (decl);
  TREE_ADDRESSABLE (decl) |= TREE_ADDRESSABLE (prevailing_decl);

  /* The linker may ask us to combine two incompatible symbols.
     Detect this case and notify the caller of required diagnostics.  */

  if (TREE_CODE (decl) == FUNCTION_DECL)
    {
      /* Merge decl state in both directions, we may still end up using
	 the new decl.  */
      DECL_POSSIBLY_INLINED (prevailing_decl) |= DECL_POSSIBLY_INLINED (decl);
      DECL_POSSIBLY_INLINED (decl) |= DECL_POSSIBLY_INLINED (prevailing_decl);

      if (warn_type_compatibility_p (TREE_TYPE (prevailing_decl),
			             TREE_TYPE (decl),
				     DECL_COMMON (decl)
				     || DECL_EXTERNAL (decl)))
	return false;

      return true;
    }

  if (warn_type_compatibility_p (TREE_TYPE (prevailing_decl),
				 TREE_TYPE (decl),
				 DECL_COMMON (decl) || DECL_EXTERNAL (decl)))
    return false;

  /* There is no point in comparing too many details of the decls here.
     The type compatibility checks or the completing of types has properly
     dealt with most issues.  */

  /* The following should all not invoke fatal errors as in non-LTO
     mode the linker wouldn't complain either.  Just emit warnings.  */

  /* Report a warning if user-specified alignments do not match.  */
  if ((DECL_USER_ALIGN (prevailing_decl) && DECL_USER_ALIGN (decl))
      && DECL_ALIGN (prevailing_decl) < DECL_ALIGN (decl))
    return false;

  if (DECL_SIZE (decl) && DECL_SIZE (prevailing_decl)
      && !tree_int_cst_equal (DECL_SIZE (decl), DECL_SIZE (prevailing_decl))
      /* As a special case do not warn about merging
	 int a[];
	 and
	 int a[]={1,2,3};
	 here the first declaration is COMMON
	 and sizeof(a) == sizeof (int).  */
      && ((!DECL_COMMON (decl) && !DECL_EXTERNAL (decl))
	  || TREE_CODE (TREE_TYPE (decl)) != ARRAY_TYPE
	  || TYPE_SIZE (TREE_TYPE (decl))
	     != TYPE_SIZE (TREE_TYPE (TREE_TYPE (decl)))))
    return false;

  return true;
}

static void
lto_symtab_resolve_symbols (void **slot)
{
  lto_symtab_entry_t e;
  lto_symtab_entry_t prevailing = NULL;

  /* Always set e->node so that edges are updated to reflect decl merging. */
  for (e = (lto_symtab_entry_t) *slot; e; e = e->next)
    {
      if (TREE_CODE (e->decl) == FUNCTION_DECL)
	e->node = cgraph_get_node (e->decl);
      else if (TREE_CODE (e->decl) == VAR_DECL)
	e->vnode = varpool_get_node (e->decl);
      if (e->resolution == LDPR_PREVAILING_DEF_IRONLY
	  || e->resolution == LDPR_PREVAILING_DEF_IRONLY_EXP
	  || e->resolution == LDPR_PREVAILING_DEF)
	prevailing = e;
    }

  /* If the chain is already resolved there is nothing else to do.  */
  if (prevailing)
    return;

  /* Find the single non-replaceable prevailing symbol and
     diagnose ODR violations.  */
  for (e = (lto_symtab_entry_t) *slot; e; e = e->next)
    {
      if (!lto_symtab_resolve_can_prevail_p (e))
	{
	  e->resolution = LDPR_RESOLVED_IR;
          e->guessed = true;
	  continue;
	}

      /* Set a default resolution - the final prevailing one will get
         adjusted later.  */
      e->resolution = LDPR_PREEMPTED_IR;
      e->guessed = true;
      if (!lto_symtab_resolve_replaceable_p (e))
	{
	  if (prevailing)
	    {
	      error_at (DECL_SOURCE_LOCATION (e->decl),
			"%qD has already been defined", e->decl);
	      inform (DECL_SOURCE_LOCATION (prevailing->decl),
		      "previously defined here");
	    }
	  prevailing = e;
	}
    }
  if (prevailing)
    goto found;

  /* Do a second round choosing one from the replaceable prevailing decls.  */
  for (e = (lto_symtab_entry_t) *slot; e; e = e->next)
    {
      if (e->resolution != LDPR_PREEMPTED_IR)
	continue;

      /* Choose the first function that can prevail as prevailing.  */
      if (TREE_CODE (e->decl) == FUNCTION_DECL)
	{
	  prevailing = e;
	  break;
	}

      /* From variables that can prevail choose the largest one.  */
      if (!prevailing
	  || tree_int_cst_lt (DECL_SIZE (prevailing->decl),
			      DECL_SIZE (e->decl)))
	prevailing = e;
    }

  if (!prevailing)
    return;

found:
  /* If current lto files represent the whole program,
    it is correct to use LDPR_PREVALING_DEF_IRONLY.
    If current lto files are part of whole program, internal
    resolver doesn't know if it is LDPR_PREVAILING_DEF
    or LDPR_PREVAILING_DEF_IRONLY.  Use IRONLY conforms to
    using -fwhole-program.  Otherwise, it doesn't
    matter using either LDPR_PREVAILING_DEF or
    LDPR_PREVAILING_DEF_IRONLY
    
    FIXME: above workaround due to gold plugin makes some
    variables IRONLY, which are indeed PREVAILING_DEF in
    resolution file.  These variables still need manual
    externally_visible attribute.  */
    prevailing->resolution = LDPR_PREVAILING_DEF_IRONLY;
    prevailing->guessed = true;
}

//.........这里部分代码省略.........
            if (DECL_LANG_FLAG_1 (node))
                fputs (" decl_1", file);
            if (DECL_LANG_FLAG_2 (node))
                fputs (" decl_2", file);
            if (DECL_LANG_FLAG_3 (node))
                fputs (" decl_3", file);
            if (DECL_LANG_FLAG_4 (node))
                fputs (" decl_4", file);
            if (DECL_LANG_FLAG_5 (node))
                fputs (" decl_5", file);
            if (DECL_LANG_FLAG_6 (node))
                fputs (" decl_6", file);
            if (DECL_LANG_FLAG_7 (node))
                fputs (" decl_7", file);

            mode = DECL_MODE (node);
            fprintf (file, " %s", GET_MODE_NAME (mode));
        }

        if ((code == VAR_DECL || code == PARM_DECL || code == RESULT_DECL)
                && DECL_BY_REFERENCE (node))
            fputs (" passed-by-reference", file);

        if (CODE_CONTAINS_STRUCT (code, TS_DECL_WITH_VIS)  && DECL_DEFER_OUTPUT (node))
            fputs (" defer-output", file);


        xloc = expand_location (DECL_SOURCE_LOCATION (node));
        fprintf (file, " file %s line %d col %d", xloc.file, xloc.line,
                 xloc.column);

        if (CODE_CONTAINS_STRUCT (code, TS_DECL_COMMON))
        {
            print_node (file, "size", DECL_SIZE (node), indent + 4);
            print_node (file, "unit size", DECL_SIZE_UNIT (node), indent + 4);

            if (code != FUNCTION_DECL || DECL_BUILT_IN (node))
                indent_to (file, indent + 3);

            if (DECL_USER_ALIGN (node))
                fprintf (file, " user");

            fprintf (file, " align %d", DECL_ALIGN (node));
            if (code == FIELD_DECL)
                fprintf (file, " offset_align " HOST_WIDE_INT_PRINT_UNSIGNED,
                         DECL_OFFSET_ALIGN (node));

            if (code == FUNCTION_DECL && DECL_BUILT_IN (node))
            {
                if (DECL_BUILT_IN_CLASS (node) == BUILT_IN_MD)
                    fprintf (file, " built-in BUILT_IN_MD %d", DECL_FUNCTION_CODE (node));
                else
                    fprintf (file, " built-in %s:%s",
                             built_in_class_names[(int) DECL_BUILT_IN_CLASS (node)],
                             built_in_names[(int) DECL_FUNCTION_CODE (node)]);
            }
        }
        if (code == FIELD_DECL)
        {
            print_node (file, "offset", DECL_FIELD_OFFSET (node), indent + 4);
            print_node (file, "bit offset", DECL_FIELD_BIT_OFFSET (node),
                        indent + 4);
            if (DECL_BIT_FIELD_TYPE (node))
                print_node (file, "bit_field_type", DECL_BIT_FIELD_TYPE (node),
                            indent + 4);
        }

static tree
build_common_decl (gfc_common_head *com, tree union_type, bool is_init)
{
  gfc_symbol *common_sym;
  tree decl;

  /* Create a namespace to store symbols for common blocks.  */
  if (gfc_common_ns == NULL)
    gfc_common_ns = gfc_get_namespace (NULL, 0);

  gfc_get_symbol (com->name, gfc_common_ns, &common_sym);
  decl = common_sym->backend_decl;

  /* Update the size of this common block as needed.  */
  if (decl != NULL_TREE)
    {
      tree size = TYPE_SIZE_UNIT (union_type);

      /* Named common blocks of the same name shall be of the same size
	 in all scoping units of a program in which they appear, but
	 blank common blocks may be of different sizes.  */
      if (!tree_int_cst_equal (DECL_SIZE_UNIT (decl), size)
	  && strcmp (com->name, BLANK_COMMON_NAME))
	gfc_warning ("Named COMMON block '%s' at %L shall be of the "
		     "same size as elsewhere (%lu vs %lu bytes)", com->name,
		     &com->where,
		     (unsigned long) TREE_INT_CST_LOW (size),
		     (unsigned long) TREE_INT_CST_LOW (DECL_SIZE_UNIT (decl)));

      if (tree_int_cst_lt (DECL_SIZE_UNIT (decl), size))
	{
	  DECL_SIZE (decl) = TYPE_SIZE (union_type);
	  DECL_SIZE_UNIT (decl) = size;
	  DECL_MODE (decl) = TYPE_MODE (union_type);
	  TREE_TYPE (decl) = union_type;
	  layout_decl (decl, 0);
	}
     }

  /* If this common block has been declared in a previous program unit,
     and either it is already initialized or there is no new initialization
     for it, just return.  */
  if ((decl != NULL_TREE) && (!is_init || DECL_INITIAL (decl)))
    return decl;

  /* If there is no backend_decl for the common block, build it.  */
  if (decl == NULL_TREE)
    {
      decl = build_decl (input_location,
			 VAR_DECL, get_identifier (com->name), union_type);
      gfc_set_decl_assembler_name (decl, gfc_sym_mangled_common_id (com));
      TREE_PUBLIC (decl) = 1;
      TREE_STATIC (decl) = 1;
      DECL_IGNORED_P (decl) = 1;
      if (!com->is_bind_c)
	DECL_ALIGN (decl) = BIGGEST_ALIGNMENT;
      else
        {
	  /* Do not set the alignment for bind(c) common blocks to
	     BIGGEST_ALIGNMENT because that won't match what C does.  Also,
	     for common blocks with one element, the alignment must be
	     that of the field within the common block in order to match
	     what C will do.  */
	  tree field = NULL_TREE;
	  field = TYPE_FIELDS (TREE_TYPE (decl));
	  if (DECL_CHAIN (field) == NULL_TREE)
	    DECL_ALIGN (decl) = TYPE_ALIGN (TREE_TYPE (field));
	}
      DECL_USER_ALIGN (decl) = 0;
      GFC_DECL_COMMON_OR_EQUIV (decl) = 1;

      gfc_set_decl_location (decl, &com->where);

      if (com->threadprivate)
	DECL_TLS_MODEL (decl) = decl_default_tls_model (decl);

      /* Place the back end declaration for this common block in
         GLOBAL_BINDING_LEVEL.  */
      common_sym->backend_decl = pushdecl_top_level (decl);
    }

  /* Has no initial values.  */
  if (!is_init)
    {
      DECL_INITIAL (decl) = NULL_TREE;
      DECL_COMMON (decl) = 1;
      DECL_DEFER_OUTPUT (decl) = 1;
    }
  else
    {
      DECL_INITIAL (decl) = error_mark_node;
      DECL_COMMON (decl) = 0;
      DECL_DEFER_OUTPUT (decl) = 0;
    }
  return decl;
}