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| author | Mark Wielaard <mjw@redhat.com> | 2015-09-14 09:49:47 +0000 |
|---|---|---|
| committer | Mark Wielaard <mark@gcc.gnu.org> | 2015-09-14 09:49:47 +0000 |
| commit | 0f876f22887f239cedca64ff170b71e5f1daaf54 (patch) | |
| tree | 69691ab92ba1ad50826f35684fac28f7495db523 /gcc/c-family/c.opt | |
| parent | cc099b03c01f74b2b8ddf87f93890bdbde2305f9 (diff) | |
| download | gcc-0f876f22887f239cedca64ff170b71e5f1daaf54.zip gcc-0f876f22887f239cedca64ff170b71e5f1daaf54.tar.gz gcc-0f876f22887f239cedca64ff170b71e5f1daaf54.tar.bz2 | |
PR28901 -Wunused-variable ignores unused const initialised variables in C
12 years ago it was decided that -Wunused-variable shouldn't warn about
static const variables because some code used const static char rcsid[]
strings which were never used but wanted in the code anyway. But as the
bug points out this hides some real bugs. These days the usage of rcsids
is not very popular anymore. So this patch changes the default to warn
about unused static const variables in C with -Wunused-variable. And it
adds a new option -Wno-unused-const-variable to turn this warning off.
For C++ this new warning is off by default, since const variables can be
used as #defines in C++. New testcases for the new defaults in C and C++
are included testing the new warning and suppressing it with an unused
attribute or using -Wno-unused-const-variable.
gcc/ChangeLog
PR c/28901
* toplev.c (check_global_declaration): Check and use
warn_unused_const_variable.
* doc/invoke.texi (Warning Options): Add -Wunused-const-variable.
(-Wunused-variable): Remove non-constant. For C implies
-Wunused-const-variable.
(-Wunused-const-variable): New.
gcc/c-family/ChangeLog
PR c/28901
* c.opt (Wunused-variable): Option from common.opt.
(Wunused-const-variable): New option.
gcc/cp/ChangeLog
PR c/28901
* cp-objcp-common.c (cxx_warn_unused_global_decl): Remove hard-coded
VAR_P TREE_READONLY override.
gcc/testsuite/ChangeLog
PR c/28901
* g++.dg/warn/unused-variable-1.C: New test.
* g++.dg/warn/unused-variable-2.C: Likewise.
* gcc.dg/unused-4.c: Adjust warning for static const.
* gcc.dg/unused-variable-1.c: New test.
* gcc.dg/unused-variable-2.c: Likewise.
From-SVN: r227742
Diffstat (limited to 'gcc/c-family/c.opt')
| -rw-r--r-- | gcc/c-family/c.opt | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/gcc/c-family/c.opt b/gcc/c-family/c.opt index d519d7a..47ba070 100644 --- a/gcc/c-family/c.opt +++ b/gcc/c-family/c.opt @@ -912,6 +912,14 @@ Wunused-result C ObjC C++ ObjC++ Var(warn_unused_result) Init(1) Warning Warn if a caller of a function, marked with attribute warn_unused_result, does not use its return value +Wunused-variable +C ObjC C++ ObjC++ LangEnabledBy(C ObjC C++ ObjC++,Wunused) +; documented in common.opt + +Wunused-const-variable +C ObjC C++ ObjC++ Var(warn_unused_const_variable) Warning LangEnabledBy(C ObjC,Wunused-variable) +Warn when a const variable is unused + Wvariadic-macros C ObjC C++ ObjC++ CPP(warn_variadic_macros) CppReason(CPP_W_VARIADIC_MACROS) Var(cpp_warn_variadic_macros) Init(0) Warning LangEnabledBy(C ObjC C++ ObjC++,Wpedantic || Wtraditional) Warn about using variadic macros |