Everywhere: Warn on function definitions without prototypes

If no header includes the prototype of a function, then it cannot be
used from outside the translation unit it was defined in. In that case,
it should be marked as `static`, in order to avoid possible ODR
problems, unnecessary exported symbols, and allow the compiler to better
optimize those.

If this warning triggers in a function defined in a header, `inline`
needs to be added, otherwise if the header is included in more than one
TU, it will fail to link with a duplicate definition error.

The reason this diff got so big is that Lagom-only code wasn't built
with this flag even in Serenity times.

Meta/Lagom/Tools/CodeGenerators/IPCCompiler/main.cpp

@@ -16,6 +16,7 @@
 #include <ctype.h>
 #include <stdio.h>
 
+namespace {
 struct Parameter {
     Vector<ByteString> attributes;
     ByteString type;
@@ -823,6 +824,7 @@ void build(StringBuilder& builder, Vector<Endpoint> const& endpoints)
     for (auto const& endpoint : endpoints)
         build_endpoint(generator.fork(), endpoint);
 }
+} // end anonymous namespace
 
 ErrorOr<int> serenity_main(Main::Arguments arguments)
 {

Meta/Lagom/Tools/CodeGenerators/LibTextCodec/GenerateEncodingIndexes.cpp

@@ -15,6 +15,7 @@
 #include <LibCore/File.h>
 #include <LibMain/Main.h>
 
+namespace {
 struct LookupTable {
     u32 first_pointer;
     u32 max_code_point;
@@ -175,6 +176,7 @@ namespace TextCodec {
     TRY(file.write_until_depleted(generator.as_string_view().bytes()));
     return {};
 }
+} // end anonymous namespace
 
 ErrorOr<int> serenity_main(Main::Arguments arguments)
 {

Meta/Lagom/Tools/CodeGenerators/LibWeb/BindingsGenerator/IDLGenerators.cpp

@@ -10,6 +10,7 @@
  * SPDX-License-Identifier: BSD-2-Clause
  */
 
+#include "IDLGenerators.h"
 #include "Namespaces.h"
 #include <AK/Array.h>
 #include <AK/LexicalPath.h>
@@ -17,10 +18,10 @@
 #include <AK/QuickSort.h>
 #include <LibIDL/Types.h>
 
-Vector<StringView> s_header_search_paths;
-
 namespace IDL {
 
+Vector<StringView> g_header_search_paths;
+
 // FIXME: Generate this automatically somehow.
 static bool is_platform_object(Type const& type)
 {
@@ -284,7 +285,7 @@ static void generate_include_for(auto& generator, auto& path)
 {
     auto forked_generator = generator.fork();
     auto path_string = path;
-    for (auto& search_path : s_header_search_paths) {
+    for (auto& search_path : g_header_search_paths) {
         if (!path.starts_with(search_path))
             continue;
         auto relative_path = LexicalPath::relative_path(path, search_path);

Meta/Lagom/Tools/CodeGenerators/LibWeb/BindingsGenerator/IDLGenerators.h

@@ -0,0 +1,33 @@
+/*
+ * Copyright (c) 2020-2023, Andreas Kling <kling@serenityos.org>
+ * Copyright (c) 2021-2023, Linus Groh <linusg@serenityos.org>
+ * Copyright (c) 2021-2023, Luke Wilde <lukew@serenityos.org>
+ * Copyright (c) 2022, Ali Mohammad Pur <mpfard@serenityos.org>
+ * Copyright (c) 2023-2024, Kenneth Myhra <kennethmyhra@serenityos.org>
+ * Copyright (c) 2023-2024, Shannon Booth <shannon@serenityos.org>
+ * Copyright (c) 2023-2024, Matthew Olsson <mattco@serenityos.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include <AK/StringBuilder.h>
+#include <LibIDL/Types.h>
+
+namespace IDL {
+
+void generate_namespace_header(IDL::Interface const&, StringBuilder&);
+void generate_namespace_implementation(IDL::Interface const&, StringBuilder&);
+void generate_constructor_header(IDL::Interface const&, StringBuilder&);
+void generate_constructor_implementation(IDL::Interface const&, StringBuilder&);
+void generate_prototype_header(IDL::Interface const&, StringBuilder&);
+void generate_prototype_implementation(IDL::Interface const&, StringBuilder&);
+void generate_iterator_prototype_header(IDL::Interface const&, StringBuilder&);
+void generate_iterator_prototype_implementation(IDL::Interface const&, StringBuilder&);
+void generate_global_mixin_header(IDL::Interface const&, StringBuilder&);
+void generate_global_mixin_implementation(IDL::Interface const&, StringBuilder&);
+
+extern Vector<StringView> g_header_search_paths;
+
+}

Meta/Lagom/Tools/CodeGenerators/LibWeb/BindingsGenerator/main.cpp

@@ -8,6 +8,7 @@
  * SPDX-License-Identifier: BSD-2-Clause
  */
 
+#include "IDLGenerators.h"
 #include "Namespaces.h"
 #include <AK/Debug.h>
 #include <AK/LexicalPath.h>
@@ -16,21 +17,6 @@
 #include <LibIDL/IDLParser.h>
 #include <LibIDL/Types.h>
 
-extern Vector<StringView> s_header_search_paths;
-
-namespace IDL {
-void generate_namespace_header(IDL::Interface const&, StringBuilder&);
-void generate_namespace_implementation(IDL::Interface const&, StringBuilder&);
-void generate_constructor_header(IDL::Interface const&, StringBuilder&);
-void generate_constructor_implementation(IDL::Interface const&, StringBuilder&);
-void generate_prototype_header(IDL::Interface const&, StringBuilder&);
-void generate_prototype_implementation(IDL::Interface const&, StringBuilder&);
-void generate_iterator_prototype_header(IDL::Interface const&, StringBuilder&);
-void generate_iterator_prototype_implementation(IDL::Interface const&, StringBuilder&);
-void generate_global_mixin_header(IDL::Interface const&, StringBuilder&);
-void generate_global_mixin_implementation(IDL::Interface const&, StringBuilder&);
-}
-
 ErrorOr<int> serenity_main(Main::Arguments arguments)
 {
     Core::ArgsParser args_parser;
@@ -47,7 +33,7 @@ ErrorOr<int> serenity_main(Main::Arguments arguments)
         .short_name = 'i',
         .value_name = "path",
         .accept_value = [&](StringView s) {
-            s_header_search_paths.append(s);
+            IDL::g_header_search_paths.append(s);
             return true;
         },
     });

Meta/Lagom/Tools/CodeGenerators/LibWeb/GenerateAriaRoles.cpp

@@ -10,34 +10,7 @@
 #include <LibCore/ArgsParser.h>
 #include <LibMain/Main.h>
 
-ErrorOr<void> generate_header_file(JsonObject& roles_data, Core::File& file);
-ErrorOr<void> generate_implementation_file(JsonObject& roles_data, Core::File& file);
-
-ErrorOr<int> serenity_main(Main::Arguments arguments)
-{
-    StringView generated_header_path;
-    StringView generated_implementation_path;
-    StringView identifiers_json_path;
-
-    Core::ArgsParser args_parser;
-    args_parser.add_option(generated_header_path, "Path to the TransformFunctions header file to generate", "generated-header-path", 'h', "generated-header-path");
-    args_parser.add_option(generated_implementation_path, "Path to the TransformFunctions implementation file to generate", "generated-implementation-path", 'c', "generated-implementation-path");
-    args_parser.add_option(identifiers_json_path, "Path to the JSON file to read from", "json-path", 'j', "json-path");
-    args_parser.parse(arguments);
-
-    auto json = TRY(read_entire_file_as_json(identifiers_json_path));
-    VERIFY(json.is_object());
-    auto roles_data = json.as_object();
-
-    auto generated_header_file = TRY(Core::File::open(generated_header_path, Core::File::OpenMode::Write));
-    auto generated_implementation_file = TRY(Core::File::open(generated_implementation_path, Core::File::OpenMode::Write));
-
-    TRY(generate_header_file(roles_data, *generated_header_file));
-    TRY(generate_implementation_file(roles_data, *generated_implementation_file));
-
-    return 0;
-}
-
+namespace {
 ErrorOr<void> generate_header_file(JsonObject& roles_data, Core::File& file)
 {
     StringBuilder builder;
@@ -387,3 +360,29 @@ NameFromSource @name@::name_from_source() const
     TRY(file.write_until_depleted(generator.as_string_view().bytes()));
     return {};
 }
+} // end anonymous namespace
+
+ErrorOr<int> serenity_main(Main::Arguments arguments)
+{
+    StringView generated_header_path;
+    StringView generated_implementation_path;
+    StringView identifiers_json_path;
+
+    Core::ArgsParser args_parser;
+    args_parser.add_option(generated_header_path, "Path to the TransformFunctions header file to generate", "generated-header-path", 'h', "generated-header-path");
+    args_parser.add_option(generated_implementation_path, "Path to the TransformFunctions implementation file to generate", "generated-implementation-path", 'c', "generated-implementation-path");
+    args_parser.add_option(identifiers_json_path, "Path to the JSON file to read from", "json-path", 'j', "json-path");
+    args_parser.parse(arguments);
+
+    auto json = TRY(read_entire_file_as_json(identifiers_json_path));
+    VERIFY(json.is_object());
+    auto roles_data = json.as_object();
+
+    auto generated_header_file = TRY(Core::File::open(generated_header_path, Core::File::OpenMode::Write));
+    auto generated_implementation_file = TRY(Core::File::open(generated_implementation_path, Core::File::OpenMode::Write));
+
+    TRY(generate_header_file(roles_data, *generated_header_file));
+    TRY(generate_implementation_file(roles_data, *generated_implementation_file));
+
+    return 0;
+}

Meta/Lagom/Tools/CodeGenerators/LibWeb/GenerateCSSMathFunctions.cpp

@@ -10,34 +10,7 @@
 #include <LibCore/ArgsParser.h>
 #include <LibMain/Main.h>
 
-ErrorOr<void> generate_header_file(JsonObject& functions_data, Core::File& file);
-ErrorOr<void> generate_implementation_file(JsonObject& functions_data, Core::File& file);
-
-ErrorOr<int> serenity_main(Main::Arguments arguments)
-{
-    StringView generated_header_path;
-    StringView generated_implementation_path;
-    StringView identifiers_json_path;
-
-    Core::ArgsParser args_parser;
-    args_parser.add_option(generated_header_path, "Path to the MathFunctions header file to generate", "generated-header-path", 'h', "generated-header-path");
-    args_parser.add_option(generated_implementation_path, "Path to the MathFunctions implementation file to generate", "generated-implementation-path", 'c', "generated-implementation-path");
-    args_parser.add_option(identifiers_json_path, "Path to the JSON file to read from", "json-path", 'j', "json-path");
-    args_parser.parse(arguments);
-
-    auto json = TRY(read_entire_file_as_json(identifiers_json_path));
-    VERIFY(json.is_object());
-    auto math_functions_data = json.as_object();
-
-    auto generated_header_file = TRY(Core::File::open(generated_header_path, Core::File::OpenMode::Write));
-    auto generated_implementation_file = TRY(Core::File::open(generated_implementation_path, Core::File::OpenMode::Write));
-
-    TRY(generate_header_file(math_functions_data, *generated_header_file));
-    TRY(generate_implementation_file(math_functions_data, *generated_implementation_file));
-
-    return 0;
-}
-
+namespace {
 ErrorOr<void> generate_header_file(JsonObject& functions_data, Core::File& file)
 {
     StringBuilder builder;
@@ -378,3 +351,29 @@ OwnPtr<CalculationNode> Parser::parse_math_function(PropertyID property_id, Func
     TRY(file.write_until_depleted(generator.as_string_view().bytes()));
     return {};
 }
+} // end anonymous namespace
+
+ErrorOr<int> serenity_main(Main::Arguments arguments)
+{
+    StringView generated_header_path;
+    StringView generated_implementation_path;
+    StringView identifiers_json_path;
+
+    Core::ArgsParser args_parser;
+    args_parser.add_option(generated_header_path, "Path to the MathFunctions header file to generate", "generated-header-path", 'h', "generated-header-path");
+    args_parser.add_option(generated_implementation_path, "Path to the MathFunctions implementation file to generate", "generated-implementation-path", 'c', "generated-implementation-path");
+    args_parser.add_option(identifiers_json_path, "Path to the JSON file to read from", "json-path", 'j', "json-path");
+    args_parser.parse(arguments);
+
+    auto json = TRY(read_entire_file_as_json(identifiers_json_path));
+    VERIFY(json.is_object());
+    auto math_functions_data = json.as_object();
+
+    auto generated_header_file = TRY(Core::File::open(generated_header_path, Core::File::OpenMode::Write));
+    auto generated_implementation_file = TRY(Core::File::open(generated_implementation_path, Core::File::OpenMode::Write));
+
+    TRY(generate_header_file(math_functions_data, *generated_header_file));
+    TRY(generate_implementation_file(math_functions_data, *generated_implementation_file));
+
+    return 0;
+}

Meta/Lagom/Tools/CodeGenerators/LibWeb/GeneratorUtil.h

@@ -13,7 +13,7 @@
 #include <LibCore/File.h>
 #include <ctype.h>
 
-String title_casify(StringView dashy_name)
+inline String title_casify(StringView dashy_name)
 {
     auto parts = dashy_name.split_view('-');
     StringBuilder builder;
@@ -28,7 +28,7 @@ String title_casify(StringView dashy_name)
     return MUST(builder.to_string());
 }
 
-String camel_casify(StringView dashy_name)
+inline String camel_casify(StringView dashy_name)
 {
     auto parts = dashy_name.split_view('-');
     StringBuilder builder;
@@ -49,14 +49,14 @@ String camel_casify(StringView dashy_name)
     return MUST(builder.to_string());
 }
 
-String snake_casify(StringView dashy_name)
+inline String snake_casify(StringView dashy_name)
 {
     // FIXME: We don't really need to convert dashy_name to a String first, but currently
     //        all the `replace` functions that take a StringView return ByteString.
     return MUST(MUST(String::from_utf8(dashy_name)).replace("-"sv, "_"sv, ReplaceMode::All));
 }
 
-ErrorOr<JsonValue> read_entire_file_as_json(StringView filename)
+inline ErrorOr<JsonValue> read_entire_file_as_json(StringView filename)
 {
     auto file = TRY(Core::File::open(filename, Core::File::OpenMode::Read));
     auto json_size = TRY(file->size());