Line data    Source code

       1              : // Copyright (C) 2021-2026 Free Software Foundation, Inc.
       2              : 
       3              : // This file is part of GCC.
       4              : 
       5              : // GCC is free software; you can redistribute it and/or modify it under
       6              : // the terms of the GNU General Public License as published by the Free
       7              : // Software Foundation; either version 3, or (at your option) any later
       8              : // version.
       9              : 
      10              : // GCC is distributed in the hope that it will be useful, but WITHOUT ANY
      11              : // WARRANTY; without even the implied warranty of MERCHANTABILITY or
      12              : // FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
      13              : // for more details.
      14              : 
      15              : // You should have received a copy of the GNU General Public License
      16              : // along with GCC; see the file COPYING3.  If not see
      17              : // <http://www.gnu.org/licenses/>.
      18              : 
      19              : #include "rust-lint-unused-var.h"
      20              : #include "rust-gcc.h"
      21              : 
      22              : namespace Rust {
      23              : namespace Analysis {
      24              : 
      25              : static bool
      26        52565 : starts_with_underscore (const char *var_name)
      27              : {
      28        52565 :   auto pos = std::string (var_name).find_last_of (':');
      29        52565 :   if (pos == std::string::npos)
      30        51636 :     return strncmp (var_name, "_", 1) == 0;
      31          929 :   return strncmp (var_name + pos + 1, "_", 1) == 0;
      32              : }
      33              : 
      34              : static void
      35        52565 : check_decl (tree *t)
      36              : {
      37        52565 :   rust_assert (TREE_CODE (*t) == VAR_DECL || TREE_CODE (*t) == PARM_DECL
      38              :                || TREE_CODE (*t) == CONST_DECL);
      39              : 
      40        52565 :   tree var_name = DECL_NAME (*t);
      41        52565 :   const char *var_name_ptr = IDENTIFIER_POINTER (var_name);
      42        52565 :   bool starts_with_under_score = starts_with_underscore (var_name_ptr);
      43        52565 :   bool is_self = strcmp (var_name_ptr, "self") == 0;
      44              : 
      45        52565 :   bool is_constant = TREE_CODE (*t) == CONST_DECL;
      46              :   // if (!is_constant)
      47              :   //   {
      48              :   //     debug_tree (*t);
      49              :   //     rust_debug ("found var-decl: used %s artifical %s underscore %s name
      50              :   //     %s",
      51              :   //              TREE_USED (*t) ? "true" : "false",
      52              :   //              DECL_ARTIFICIAL (*t) ? "true" : "false",
      53              :   //              starts_with_under_score ? "true" : "false", var_name_ptr);
      54              :   //   }
      55              : 
      56         2818 :   if (!TREE_USED (*t) && !DECL_ARTIFICIAL (*t) && !starts_with_under_score
      57        55344 :       && !is_self)
      58              :     {
      59         1959 :       warning_at (DECL_SOURCE_LOCATION (*t),
      60         3891 :                   is_constant ? OPT_Wunused_const_variable_
      61              :                               : OPT_Wunused_variable,
      62              :                   "unused name %qE", *t);
      63              :     }
      64        52565 : }
      65              : 
      66              : static tree
      67       378831 : unused_var_walk_fn (tree *t, int *, void *)
      68              : {
      69       378831 :   switch (TREE_CODE (*t))
      70              :     {
      71        37219 :     case VAR_DECL:
      72        37219 :     case CONST_DECL:
      73        37219 :       check_decl (t);
      74        37219 :       break;
      75              : 
      76              :     default:
      77              :       break;
      78              :     }
      79       378831 :   return NULL_TREE;
      80              : }
      81              : 
      82              : void
      83         4023 : UnusedVariables::Lint (Compile::Context &ctx)
      84              : {
      85        18797 :   for (auto &fndecl : ctx.get_func_decls ())
      86              :     {
      87        29578 :       for (tree p = DECL_ARGUMENTS (fndecl); p != NULL_TREE; p = DECL_CHAIN (p))
      88              :         {
      89        14804 :           check_decl (&p);
      90              :         }
      91              : 
      92        14774 :       walk_tree_without_duplicates (&DECL_SAVED_TREE (fndecl),
      93              :                                     &unused_var_walk_fn, &ctx);
      94              :     }
      95              : 
      96         4069 :   for (auto &var : ctx.get_var_decls ())
      97              :     {
      98           46 :       tree decl = var->get_decl ();
      99           46 :       check_decl (&decl);
     100              :     }
     101              : 
     102         4519 :   for (auto &const_decl : ctx.get_const_decls ())
     103              :     {
     104          496 :       check_decl (&const_decl);
     105              :     }
     106         4023 : }
     107              : 
     108              : } // namespace Analysis
     109              : } // namespace Rust