Re: [PATCH] Update or add fall through comments in switches

[Jeff Law <law@redhat.com>]

On 08/11/2016 07:43 AM, Marek Polacek wrote:
> This patch either updates fall through comments so that our warning
> machinery recognizes them, or annotates code with new FALLTHRU comments
> so that intended fall through cases are marked and the compiler wouldn't
> warn.
>
> I'd like to get this in before I post another patches to keep this mess
> more manageable.
>
> Bootstrapped/regtested on x86_64-linux, ok for trunk?
>
> 2016-08-11  Marek Polacek  <polacek@redhat.com>
>
> 	PR c/7652
> gcc/
> 	* alias.c (find_base_value): Adjust fall through comment.
> 	* cfgexpand.c (expand_debug_expr): Likewise.
> 	* combine.c (find_split_point): Likewise.
> 	(expand_compound_operation): Likewise.  Add FALLTHRU.
> 	(make_compound_operation): Adjust fall through comment.
> 	(canon_reg_for_combine): Add FALLTHRU.
> 	(force_to_mode): Adjust fall through comment.
> 	(simplify_shift_const_1): Likewise.
> 	(simplify_comparison): Likewise.
> 	* config/aarch64/aarch64-builtins.c (aarch64_simd_expand_args): Add
> 	FALLTHRU.
> 	* config/aarch64/predicates.md: Likewise.
> 	* config/i386/i386.c (function_arg_advance_32): Likewise.
> 	(ix86_gimplify_va_arg): Likewise.
> 	(print_reg): Likewise.
> 	(ix86_print_operand): Likewise.
> 	(ix86_build_const_vector): Likewise.
> 	(ix86_expand_branch): Likewise.
> 	(ix86_sched_init_global): Adjust fall through comment.
> 	(ix86_expand_args_builtin): Add FALLTHRU.
> 	(ix86_expand_builtin): Likewise.
> 	(ix86_expand_vector_init_one_var): Likewise.
> 	* config/rs6000/rs6000.c (rs6000_emit_vector_compare_inner): Likewise.
> 	(rs6000_adjust_cost): Likewise.
> 	(insn_must_be_first_in_group): Likewise.
> 	* config/rs6000/rs6000.md: Likewise.  Adjust fall through comment.
> 	* dbxout.c (dbxout_symbol): Adjust fall through comment.
> 	* df-scan.c (df_uses_record): Likewise.
> 	* dojump.c (do_jump): Add FALLTHRU.
> 	* dwarf2out.c (mem_loc_descriptor): Likewise.  Adjust fall through
> 	comment.
> 	(resolve_args_picking_1): Adjust fall through comment.
> 	(loc_list_from_tree_1): Likewise.
> 	* expmed.c (make_tree): Likewise.
> 	* expr.c (expand_expr_real_2): Add FALLTHRU.
> 	(expand_expr_real_1): Likewise.  Adjust fall through comment.
> 	* fold-const.c (const_binop): Adjust fall through comment.
> 	(fold_truth_not_expr): Likewise.
> 	(fold_cond_expr_with_comparison): Add FALLTHRU.
> 	(fold_binary_loc): Likewise.
> 	(contains_label_1): Adjust fall through comment.
> 	(multiple_of_p): Likewise.
> 	* gcov-tool.c (process_args): Add FALLTHRU.
> 	* genattrtab.c (check_attr_test): Likewise.
> 	(write_test_expr): Likewise.
> 	* genconfig.c (walk_insn_part): Likewise.
> 	* genpreds.c (validate_exp): Adjust fall through comment.
> 	(needs_variable): Likewise.
> 	* gensupport.c (get_alternatives_number): Add FALLTHRU.
> 	(subst_dup): Likewise.
> 	* gimple-pretty-print.c (dump_gimple_assign): Likewise.
> 	* gimplify.c (gimplify_addr_expr): Adjust fall through comment.
> 	(gimplify_scan_omp_clauses): Add FALLTHRU.
> 	(goa_stabilize_expr): Likewise.
> 	* graphite-isl-ast-to-gimple.c (substitute_ssa_name): Adjust fall
> 	through comment.
> 	* hsa-gen.c (get_address_from_value): Likewise.
> 	* ipa-icf.c (sem_function::hash_stmt): Likewise.
> 	* ira.c (ira_setup_alts): Add FALLTHRU.
> 	* lra-eliminations.c (lra_eliminate_regs_1): Adjust fall through
> 	comment.
> 	* lto-streamer-out.c (lto_output_tree_ref): Add FALLTHRU.
> 	* opts.c (common_handle_option): Likewise.
> 	* read-rtl.c (read_rtx_code): Likewise.
> 	* real.c (round_for_format): Likewise.
> 	* recog.c (asm_operand_ok): Likewise.
> 	* reginfo.c (reg_scan_mark_refs): Adjust fall through comment.
> 	* reload1.c (set_label_offsets): Likewise.
> 	(eliminate_regs_1): Likewise.
> 	(reload_reg_reaches_end_p): Likewise.
> 	* rtlanal.c (commutative_operand_precedence): Add FALLTHRU.
> 	(rtx_cost): Likewise.
> 	* sched-rgn.c (is_exception_free): Likewise.
> 	* simplify-rtx.c (simplify_rtx): Adjust fall through comment.
> 	* stor-layout.c (int_mode_for_mode): Likewise.
> 	* toplev.c (print_to_asm_out_file): Likewise.
> 	(print_to_stderr): Likewise.
> 	* tree-cfg.c (gimple_verify_flow_info): Likewise.
> 	* tree-chrec.c (chrec_fold_plus_1): Add FALLTHRU.
> 	(chrec_fold_multiply): Likewise.
> 	(evolution_function_is_invariant_rec_p): Likewise.
> 	(for_each_scev_op): Likewise.
> 	* tree-data-ref.c (siv_subscript_p): Likewise.
> 	(get_references_in_stmt): Likewise.
> 	* tree.c (find_placeholder_in_expr): Adjust fall through comment.
> 	(substitute_in_expr): Likewise.
> 	(type_cache_hasher::equal): Likewise.
> 	(walk_type_fields): Likewise.
> 	* var-tracking.c (adjust_mems): Add FALLTHRU.
> 	(set_dv_changed): Adjust fall through comment.
> 	* varasm.c (default_function_section): Add FALLTHRU.
> gcc/c-family/
> 	* c-common.c (scalar_to_vector): Adjust fall through comment.
> 	* c-opts.c (c_common_handle_option): Likewise.
> 	* c-pragma.c (handle_pragma_pack): Add FALLTHRU.
> 	* c-pretty-print.c (c_pretty_printer::postfix_expression): Adjust
> 	fall through comment.
> 	* cilk.c (extract_free_variables): Add FALLTHRU.
> gcc/c/
> 	* c-parser.c (c_parser_external_declaration): Add FALLTHRU.
> 	(c_parser_postfix_expression): Likewise.
> 	* c-typeck.c (build_unary_op): Adjust fall through comment.
> 	(c_mark_addressable): Likewise.
> gcc/cp/
> 	* call.c (add_builtin_candidate): Add FALLTHRU.
> 	(build_integral_nontype_arg_conv): Adjust fall through comment.
> 	(build_new_op_1): Add FALLTHRU.
> 	(convert_like_real): Adjust fall through comment.
> 	* class.c (fixed_type_or_null): Likewise.
> 	* constexpr.c (cxx_eval_constant_expression): Likewise.
> 	(potential_constant_expression_1): Likewise.  Add FALLTHRU.
> 	* cp-gimplify.c (cp_gimplify_expr): Adjust fall through comment.
> 	(cp_fold): Add FALLTHRU.
> 	* cvt.c (build_expr_type_conversion): Adjust fall through comment.
> 	* cxx-pretty-print.c (pp_cxx_unqualified_id): Add FALLTHRU.
> 	(pp_cxx_qualified_id): Likewise.
> 	(cxx_pretty_printer::constant): Adjust fall through comment.
> 	(cxx_pretty_printer::primary_expression): Add FALLTHRU.
> 	(pp_cxx_pm_expression): Adjust fall through comment.
> 	(cxx_pretty_printer::expression): Add FALLTHRU.
> 	(cxx_pretty_printer::declaration_specifiers): Reformat code.
> 	(pp_cxx_type_specifier_seq): Adjust fall through comment.
> 	(pp_cxx_ptr_operator): Likewise.  Add FALLTHRU.
> 	* error.c (dump_type): Adjust fall through comment.
> 	(dump_decl): Likewise.
> 	* mangle.c (write_type): Likewise.
> 	* method.c (synthesized_method_walk): Add FALLTHRU.
> 	* name-lookup.c (arg_assoc_type): Likewise.
> 	* parser.c (cp_lexer_print_token): Adjust fall through comment.
> 	(cp_parser_primary_expression): Add FALLTHRU.
> 	(cp_parser_operator): Likewise.
> 	* pt.c (find_parameter_packs_r): Likewise.
> 	(tsubst_aggr_type): Adjust fall through comment.
> 	* semantics.c (finish_omp_clauses): Add FALLTHRU.
> 	* tree.c (lvalue_kind): Likewise.
> gcc/fortran/
> 	* decl.c (match_attr_spec): Add FALLTHRU.
> 	* primary.c (match_arg_list_function): Likewise.
> 	* resolve.c (resolve_operator): Adjust fall through comment.
> 	(fixup_charlen): Add FALLTHRU.
> 	(resolve_allocate_expr): Adjust fall through comment.
> 	* trans-array.c (gfc_conv_ss_startstride): Add FALLTHRU.
> 	* trans-intrinsic.c (gfc_conv_intrinsic_len): Adjust fall through
> 	comment.
> gcc/java/
> 	* expr.c (java_truthvalue_conversion): Adjust fall through comment.
> 	* jcf-io.c (verify_constant_pool): Likewise.
> 	* typeck.c (promote_type): Likewise.
> gcc/objc/
> 	* objc-encoding.c (encode_type): Add FALLTHRU.
> libcpp/
> 	* lex.c (search_line_fast): Add FALLTHRU.
> 	(_cpp_lex_direct): Likewise.
> 	(cpp_token_val_index): Adjust fall through comment.
> 	* macro.c (parse_params): Add FALLTHRU.
> 	* pch.c (count_defs): Adjust fall through comment.
> 	(write_defs): Likewise.
> libiberty/
> 	* cp-demangle.c (d_print_mod): Add FALLTHRU.
I just spot-checked, but given you're just adding/updating comments, 
that seems reasonable.

Ok for the trunk.

jeff