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[Bug c/18624] GCC does not detect local variable set but never used
- From: "jakub at gcc dot gnu dot org" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: 7 Apr 2010 20:34:09 -0000
- Subject: [Bug c/18624] GCC does not detect local variable set but never used
- References: <bug-18624-9596@http.gcc.gnu.org/bugzilla/>
- Reply-to: gcc-bugzilla at gcc dot gnu dot org
------- Comment #23 from jakub at gcc dot gnu dot org 2010-04-07 20:34 -------
Subject: Bug 18624
Author: jakub
Date: Wed Apr 7 20:33:36 2010
New Revision: 158086
URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=158086
Log:
PR c/18624
* tree.h (DECL_READ_P): Define.
(struct tree_decl_common): Add decl_read_flag.
* c-decl.c (pop_scope): If TREE_USED but !DECL_READ_P, issue
a set but not used warning.
(merge_decls): Merge DECL_READ_P flag.
(finish_decl, build_compound_literal): Set DECL_READ_P flag.
(finish_function): Issue -Wunused-but-set-parameter diagnostics.
* c-common.c (handle_used_attribute, handle_unused_attribute):
Likewise.
* c-tree.h (default_function_array_read_conversion, mark_exp_read):
New prototypes.
* c-typeck.c (default_function_array_read_conversion, mark_exp_read):
New functions.
(default_conversion, c_process_expr_stmt): Call mark_exp_read.
* c-parser.c (c_parser_initializer, c_parser_expr_no_commas,
c_parser_binary_expression, c_parser_cast_expression,
c_parser_expr_list, c_parser_omp_atomic, c_parser_omp_for_loop):
Call default_function_array_read_conversion instead of
default_function_array_conversion where needed.
(c_parser_unary_expression, c_parser_conditional_expression,
c_parser_postfix_expression_after_primary, c_parser_initelt):
Likewise. Call mark_exp_read where needed.
(c_parser_statement_after_labels, c_parser_asm_operands,
c_parser_typeof_specifier, c_parser_sizeof_expression,
c_parser_alignof_expression, c_parser_initval): Call mark_exp_read
where needed.
* common.opt (Wunused-but-set-variable, Wunused-but-set-parameter):
New.
* toplev.c (warn_unused_but_set_variable): Default to warn_unused.
(warn_unused_but_set_parameter): Default to warn_unused
&& extra_warnings.
* doc/invoke.texi: Document -Wunused-but-set-variable and
-Wunused-but-set-parameter.
* objc-act.c (finish_var_decl, objc_begin_catch_clause,
really_start_method, get_super_receiver, handle_class_ref): Set
DECL_READ_P in addition to TREE_USED.
* gcc.dg/Wunused-var-1.c: New test.
* gcc.dg/Wunused-var-2.c: New test.
* gcc.dg/Wunused-var-3.c: New test.
* gcc.dg/Wunused-var-4.c: New test.
* gcc.dg/Wunused-var-5.c: New test.
* gcc.dg/Wunused-var-6.c: New test.
* gcc.dg/Wunused-parm-1.c: New test.
Added:
trunk/gcc/testsuite/gcc.dg/Wunused-parm-1.c
trunk/gcc/testsuite/gcc.dg/Wunused-var-1.c
trunk/gcc/testsuite/gcc.dg/Wunused-var-2.c
trunk/gcc/testsuite/gcc.dg/Wunused-var-3.c
trunk/gcc/testsuite/gcc.dg/Wunused-var-4.c
trunk/gcc/testsuite/gcc.dg/Wunused-var-5.c
trunk/gcc/testsuite/gcc.dg/Wunused-var-6.c
Modified:
trunk/gcc/ChangeLog
trunk/gcc/c-common.c
trunk/gcc/c-decl.c
trunk/gcc/c-parser.c
trunk/gcc/c-tree.h
trunk/gcc/c-typeck.c
trunk/gcc/common.opt
trunk/gcc/doc/invoke.texi
trunk/gcc/objc/ChangeLog
trunk/gcc/objc/objc-act.c
trunk/gcc/testsuite/ChangeLog
trunk/gcc/toplev.c
trunk/gcc/tree.h
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18624