use [[gnu::...]] attributes

src/db/Count.hxx

@@ -4,8 +4,6 @@
 #ifndef MPD_DB_COUNT_HXX
 #define MPD_DB_COUNT_HXX
 
-#include "util/Compiler.h"
-
 #include <cstdint>
 
 enum TagType : uint8_t;
@@ -13,7 +11,6 @@ struct Partition;
 class Response;
 class SongFilter;
 
-gcc_nonnull(3)
 void
 PrintSongCount(Response &r, const Partition &partition, const char *name,
 	       const SongFilter *filter,

src/db/DatabasePlaylist.hxx

@@ -4,14 +4,11 @@
 #ifndef MPD_DATABASE_PLAYLIST_HXX
 #define MPD_DATABASE_PLAYLIST_HXX
 
-#include "util/Compiler.h"
-
 class Database;
 class Storage;
 struct DatabaseSelection;
 class PlaylistFileEditor;
 
-gcc_nonnull(3)
 void
 search_add_to_playlist(const Database &db, const Storage *storage,
 		       const char *playlist_path_utf8,

src/db/DatabasePrint.cxx

@@ -21,7 +21,7 @@
 
 #include <functional>
 
-gcc_pure
+[[gnu::pure]]
 static const char *
 ApplyBaseFlag(const char *uri, bool base) noexcept
 {

src/db/Helpers.cxx

@@ -12,7 +12,7 @@
 #include <string.h>
 
 struct StringLess {
-	gcc_pure
+	[[gnu::pure]]
 	bool operator()(const char *a, const char *b) const noexcept {
 		return strcmp(a, b) < 0;
 	}

src/db/plugins/ProxyDatabasePlugin.cxx

@@ -16,7 +16,6 @@
 #include "song/UriSongFilter.hxx"
 #include "song/BaseSongFilter.hxx"
 #include "song/TagSongFilter.hxx"
-#include "util/Compiler.h"
 #include "config/Block.hxx"
 #include "tag/Builder.hxx"
 #include "tag/Tag.hxx"
@@ -265,7 +264,7 @@ ProxySong::ProxySong(const mpd_song *song)
 	tag_builder.Commit(tag2);
 }
 
-gcc_const
+[[gnu::const]]
 static enum mpd_tag_type
 Convert(TagType tag_type) noexcept
 {
@@ -694,7 +693,7 @@ Visit(struct mpd_connection *connection,
 		      visit_directory, visit_song, visit_playlist);
 }
 
-gcc_pure
+[[gnu::pure]]
 static bool
 Match(const SongFilter *filter, const LightSong &song) noexcept
 {
@@ -864,7 +863,7 @@ try {
 	throw;
 }
 
-gcc_pure
+[[gnu::pure]]
 static bool
 IsFilterSupported(const ISongFilter &f) noexcept
 {
@@ -890,7 +889,7 @@ IsFilterSupported(const ISongFilter &f) noexcept
 		return false;
 }
 
-gcc_pure
+[[gnu::pure]]
 static bool
 IsFilterFullySupported(const SongFilter &filter,
 		       const struct mpd_connection *connection) noexcept
@@ -908,7 +907,7 @@ IsFilterFullySupported(const SongFilter &filter,
 			   [](const auto &item) { return IsFilterSupported(*item); });
 }
 
-gcc_pure
+[[gnu::pure]]
 static bool
 IsFilterFullySupported(const SongFilter *filter,
 		       const struct mpd_connection *connection) noexcept
@@ -917,7 +916,7 @@ IsFilterFullySupported(const SongFilter *filter,
 		IsFilterFullySupported(*filter, connection);
 }
 
-gcc_pure
+[[gnu::pure]]
 static bool
 IsSortSupported(TagType tag_type,
 		const struct mpd_connection *connection) noexcept
@@ -939,7 +938,7 @@ IsSortSupported(TagType tag_type,
 	return Convert(tag_type) != MPD_TAG_COUNT;
 }
 
-gcc_pure
+[[gnu::pure]]
 static DatabaseSelection
 CheckSelection(DatabaseSelection selection,
 	       struct mpd_connection *connection) noexcept

src/db/plugins/simple/Directory.cxx

@@ -193,7 +193,7 @@ Directory::FindSong(std::string_view name_utf8) const noexcept
 	return nullptr;
 }
 
-gcc_pure
+[[gnu::pure]]
 static bool
 directory_cmp(const Directory &a, const Directory &b) noexcept
 {

src/db/plugins/simple/DirectorySave.cxx

@@ -25,7 +25,7 @@
 #define DIRECTORY_BEGIN "begin: "
 #define DIRECTORY_END "end: "
 
-gcc_const
+[[gnu::const]]
 static const char *
 DeviceToTypeString(unsigned device) noexcept
 {
@@ -44,7 +44,7 @@ DeviceToTypeString(unsigned device) noexcept
 	}
 }
 
-gcc_pure
+[[gnu::pure]]
 static unsigned
 ParseTypeString(const char *type) noexcept
 {

src/db/plugins/simple/SimpleDatabasePlugin.cxx

@@ -248,7 +248,7 @@ SimpleDatabase::ReturnSong([[maybe_unused]] const LightSong *song) const noexcep
 	}
 }
 
-gcc_const
+[[gnu::const]]
 static DatabaseSelection
 CheckSelection(DatabaseSelection selection) noexcept
 {

src/db/plugins/simple/Song.cxx

@@ -47,7 +47,7 @@ Song::GetURI() const noexcept
 /**
  * Path name traversal of a #Directory.
  */
-gcc_pure
+[[gnu::pure]]
 static const Directory *
 FindTargetDirectory(const Directory &base, std::string_view path) noexcept
 {
@@ -69,7 +69,7 @@ FindTargetDirectory(const Directory &base, std::string_view path) noexcept
 /**
  * Path name traversal of a #Song.
  */
-gcc_pure
+[[gnu::pure]]
 static const Song *
 FindTargetSong(const Directory &_directory, std::string_view target) noexcept
 {

src/db/plugins/simple/SongSort.cxx

@@ -60,7 +60,7 @@ compare_tag_item(const Tag &a, const Tag &b, TagType type) noexcept
 }
 
 /* Only used for sorting/searchin a songvec, not general purpose compares */
-gcc_pure
+[[gnu::pure]]
 static bool
 song_cmp(const Song &a, const Song &b) noexcept
 {

src/db/plugins/upnp/UpnpDatabasePlugin.cxx

@@ -563,7 +563,7 @@ UpnpDatabase::VisitServer(const ContentDirectoryService &server,
 	}
 }
 
-gcc_const
+[[gnu::const]]
 static DatabaseSelection
 CheckSelection(DatabaseSelection selection) noexcept
 {

src/db/update/InotifyUpdate.cxx

@@ -14,7 +14,6 @@
 #include "fs/FileInfo.hxx"
 #include "fs/Traits.hxx"
 #include "thread/Mutex.hxx"
-#include "util/Compiler.h"
 #include "Log.hxx"
 
 #include <cassert>
@@ -61,10 +60,10 @@ struct WatchDirectory {
 
 	void LoadExcludeList(Path directory_path) noexcept;
 
-	[[nodiscard]] gcc_pure
+	[[nodiscard]] [[gnu::pure]]
 	unsigned GetDepth() const noexcept;
 
-	[[nodiscard]] gcc_pure
+	[[nodiscard]] [[gnu::pure]]
 	AllocatedPath GetUriFS() const noexcept;
 };
 
@@ -137,7 +136,7 @@ WatchDirectory::GetUriFS() const noexcept
 }
 
 /* we don't look at "." / ".." nor files with newlines in their name */
-gcc_pure
+[[gnu::pure]]
 static bool
 SkipFilename(Path name) noexcept
 {
@@ -210,7 +209,7 @@ try {
 	LogError(std::current_exception());
 }
 
-gcc_pure
+[[gnu::pure]]
 unsigned
 WatchDirectory::GetDepth() const noexcept
 {

src/db/update/SpecialDirectory.cxx

@@ -7,7 +7,7 @@
 #include "playlist/PlaylistRegistry.hxx"
 #include "fs/Traits.hxx"
 
-gcc_pure
+[[gnu::pure]]
 static bool
 HaveArchivePluginForFilename(const char *filename) noexcept
 {
@@ -21,7 +21,7 @@ HaveArchivePluginForFilename(const char *filename) noexcept
 #endif
 }
 
-gcc_pure
+[[gnu::pure]]
 static bool
 HaveContainerPluginForFilename(const char *filename) noexcept
 {
@@ -31,7 +31,7 @@ HaveContainerPluginForFilename(const char *filename) noexcept
 		decoder_plugins_supports_suffix(suffix);
 }
 
-gcc_pure
+[[gnu::pure]]
 static bool
 HavePlaylistPluginForFilename(const char *filename) noexcept
 {

src/db/update/Walk.cxx

@@ -215,14 +215,14 @@ try {
 }
 
 /* we don't look at files with newlines in their name */
-gcc_pure
+[[gnu::pure]]
 static bool
 skip_path(const char *name_utf8) noexcept
 {
 	return std::strchr(name_utf8, '\n') != nullptr;
 }
 
-gcc_pure
+[[gnu::pure]]
 bool
 UpdateWalk::SkipSymlink(const Directory *directory,
 			std::string_view utf8_name) const noexcept