* common.opt (-Wattributes): New.  Default true.
* doc/invoke.texi (-Wno-attributes): Document.

* attribs.c (decl_attributes): Move warning control from if() to
warning(OPT_*).
* c-common.c (handle_packed_attribute): Likewise.
(handle_nocommon_attribute): Likewise.
(handle_common_attribute): Likewise.
(handle_noreturn_attribute): Likewise.
(handle_noinline_attribute): Likewise.
(handle_always_inline_attribute): Likewise.
(handle_used_attribute): Likewise.
(handle_unused_attribute): Likewise.
(handle_const_attribute): Likewise.
(handle_transparent_union_attribute): Likewise.
(handle_constructor_attribute): Likewise.
(handle_destructor_attribute): Likewise.
(handle_mode_attribute): Likewise.
(handle_alias_attribute): Likewise.
(handle_visibility_attribute): Likewise.
(handle_tls_model_attribute): Likewise.
(handle_malloc_attribute): Likewise.
(handle_returns_twice_attribute): Likewise.
(handle_pure_attribute): Likewise.
(handle_deprecated_attribute): Likewise.
(handle_vector_size_attribute): Likewise.
(handle_nothrow_attribute): Likewise.
(handle_cleanup_attribute): Likewise.
(handle_warn_unused_result_attribute): Likewise.
(handle_sentinel_attribute): Likewise.
* c-decl.c (diagnose_mismatched_decls): Likewise.
(start_decl): Likewise.
(grokdeclarator): Likewise.
(start_function): Likewise.
* c-format.c (check_function_format): Likewise.
* stor-layout.c (place_field): Likewise.
(finalize_record_size): Likewise.
* tree.c (handle_dll_attribute)): Likewise.
* varasm.c (default_assemble_visibility): Likewise.
* config/darwin.c (darwin_handle_weak_import_attribute): Likewise.
(darwin_assemble_visibility): Likewise.
* config/arc/arc.c (arc_handle_interrupt_attribute): Likewise.
* config/arm/arm.c (arm_handle_fndecl_attribute): Likewise.
(arm_handle_isr_attribute): Likewise.
* config/avr/avr.c (avr_handle_progmem_attribute): Likewise.
(avr_handle_fndecl_attribute): Likewise.
* config/bfin/bfin.c (handle_int_attribute): Likewise.
* config/c4x/c4x.c (c4x_handle_fntype_attribute): Likewise.
* config/h8300/h8300.c (h8300_handle_fndecl_attribute): Likewise.
(h8300_handle_eightbit_data_attribute): Likewise.
(h8300_handle_tiny_data_attribute): Likewise.
* config/i386/i386.c (ix86_handle_cdecl_attribute): Likewise.
(ix86_handle_regparm_attribute): Likewise.
(ix86_handle_struct_attribute): Likewise.
* config/i386/winnt.c (ix86_handle_shared_attribute): Likewise.
(i386_pe_encode_section_info): Likewise.
* config/ia64/ia64.c (ia64_handle_model_attribute): Likewise.
* config/ip2k/ip2k.c (ip2k_handle_progmem_attribute): Likewise.
(ip2k_handle_fndecl_attribute): Likewise.
* config/m32r/m32r.c (m32r_handle_model_attribute): Likewise.
* config/m68hc11/m68hc11 (m68hc11_handle_page0_attribute): Likewise.
(m68hc11_handle_fntype_attribute): Likewise.
(m68hc11_encode_section_info): Likewise.
* config/m68k/m68k.c (m68k_handle_fndecl_attribute): Likewise.
* config/mcore/mcore.c (mcore_handle_naked_attribute): Likewise.
* config/ns32k/ns32k.c (ns32k_handle_fntype_attribute): Likewise.
* config/rs6000/rs6000.c (rs6000_handle_longcall_attribute): Likewise.
* config/sh/sh.c (sh_handle_interrupt_handler_attribute): Likewise.
(sh_handle_sp_switch_attribute): Likewise.
(sh_handle_trap_exit_attribute): Likewise.
* config/sh/symbian.c (sh_symbian_dllimport_p): Likewise.
(sh_symbian_handle_dll_attribute): Likewise.
* config/stormy16/stormy16.c (xstormy16_handle_interrupt_attribute): Likewise.
(xstormy16_handle_below100_attribute): Likewise.
* config/v850/v850.c (v850_handle_interrupt_attribute): Likewise.

[testsuite]

* gcc.dg/Wattributes-1.c: New.
* gcc.dg/Wattributes-2.c: New.
* gcc.dg/Wattributes-3.c: New.

[cp]

* decl.c (duplicate_decls): Move warning control from if() to
warning(OPT_*).
* name-lookup.c (parse_using_directive): Likewise.
* parser.c (cp_parser_elaborated_type_specifier): Likewise.
(cp_parser_init_declarator): Likewise.
* tree.c (handle_com_interface_attribute): Likewise.

[java]

* class.c (set_constant_value): Move warning control from if() to
warning(OPT_*).

From-SVN: r100136