more [[gnu::...]] attributes

src/IdleFlags.hxx

@@ -25,8 +25,6 @@
 #ifndef MPD_IDLE_FLAGS_HXX
 #define MPD_IDLE_FLAGS_HXX
 
-#include "util/Compiler.h"
-
 /** song database has been updated*/
 static constexpr unsigned IDLE_DATABASE = 0x1;
 
@@ -73,7 +71,7 @@ static constexpr unsigned IDLE_PARTITION = 0x2000;
 /**
  * Get idle names
  */
-gcc_const
+[[gnu::const]]
 const char*const*
 idle_get_names() noexcept;
 
@@ -81,7 +79,7 @@ idle_get_names() noexcept;
  * Parse an idle name and return its mask.  Returns 0 if the given
  * name is unknown.
  */
-gcc_nonnull_all gcc_pure
+[[gnu::nonnull]] [[gnu::pure]]
 unsigned
 idle_parse_name(const char *name) noexcept;
 

src/Instance.hxx

@@ -24,7 +24,6 @@
 #include "event/Loop.hxx"
 #include "event/Thread.hxx"
 #include "event/MaskMonitor.hxx"
-#include "util/Compiler.h"
 
 #ifdef ENABLE_SYSTEMD_DAEMON
 #include "lib/systemd/Watchdog.hxx"
@@ -168,7 +167,7 @@ struct Instance final
 	 * Find a #Partition with the given name.  Returns nullptr if
 	 * no such partition was found.
 	 */
-	gcc_pure
+	[[gnu::pure]]
 	Partition *FindPartition(const char *name) noexcept;
 
 	void DeletePartition(Partition &partition) noexcept;

src/Mapper.hxx

@@ -24,7 +24,6 @@
 #ifndef MPD_MAPPER_HXX
 #define MPD_MAPPER_HXX
 
-#include "util/Compiler.h"
 #include "config.h"
 
 #include <string>
@@ -44,7 +43,7 @@ mapper_init(AllocatedPath &&playlist_dir);
  * is basically done by converting the URI to the file system charset
  * and prepending the music directory.
  */
-gcc_pure
+[[gnu::pure]]
 AllocatedPath
 map_uri_fs(const char *uri) noexcept;
 
@@ -56,7 +55,7 @@ map_uri_fs(const char *uri) noexcept;
  * @return the relative path in UTF-8, or an empty string if mapping
  * failed
  */
-gcc_pure
+[[gnu::pure]]
 std::string
 map_fs_to_utf8(Path path_fs) noexcept;
 
@@ -65,7 +64,7 @@ map_fs_to_utf8(Path path_fs) noexcept;
 /**
  * Returns the playlist directory.
  */
-gcc_const
+[[gnu::const]]
 const AllocatedPath &
 map_spl_path() noexcept;
 
@@ -75,7 +74,7 @@ map_spl_path() noexcept;
  *
  * @return the path in file system encoding, or nullptr if mapping failed
  */
-gcc_pure
+[[gnu::pure]]
 AllocatedPath
 map_spl_utf8_to_fs(const char *name) noexcept;
 

src/MixRampInfo.hxx

@@ -20,8 +20,6 @@
 #ifndef MPD_MIX_RAMP_INFO_HXX
 #define MPD_MIX_RAMP_INFO_HXX
 
-#include "util/Compiler.h"
-
 #include <string>
 
 class MixRampInfo {
@@ -35,17 +33,17 @@ public:
 		end.clear();
 	}
 
-	gcc_pure
+	[[gnu::pure]]
 	bool IsDefined() const noexcept {
 		return !start.empty() || !end.empty();
 	}
 
-	gcc_pure
+	[[gnu::pure]]
 	const char *GetStart() const noexcept {
 		return start.empty() ? nullptr : start.c_str();
 	}
 
-	gcc_pure
+	[[gnu::pure]]
 	const char *GetEnd() const noexcept {
 		return end.empty() ? nullptr : end.c_str();
 	}

src/MusicBuffer.hxx

@@ -63,7 +63,7 @@ public:
 	 * is the same value which was passed to the constructor
 	 * music_buffer_new().
 	 */
-	gcc_pure
+	[[gnu::pure]]
 	unsigned GetSize() const noexcept {
 		return buffer.GetCapacity();
 	}

src/MusicChunk.hxx

@@ -105,7 +105,7 @@ struct MusicChunkInfo {
 	 * Checks if the audio format if the chunk is equal to the
 	 * specified audio_format.
 	 */
-	gcc_pure
+	[[gnu::pure]]
 	bool CheckFormat(AudioFormat audio_format) const noexcept;
 #endif
 };

src/MusicPipe.hxx

@@ -22,7 +22,6 @@
 
 #include "MusicChunkPtr.hxx"
 #include "thread/Mutex.hxx"
-#include "util/Compiler.h"
 
 #ifndef NDEBUG
 #include "pcm/AudioFormat.hxx"
@@ -59,7 +58,7 @@ public:
 	 * Checks if the audio format if the chunk is equal to the specified
 	 * audio_format.
 	 */
-	gcc_pure
+	[[gnu::pure]]
 	bool CheckFormat(AudioFormat other) const noexcept {
 		return !audio_format.IsDefined() ||
 			audio_format == other;
@@ -68,7 +67,7 @@ public:
 	/**
 	 * Checks if the specified chunk is enqueued in the music pipe.
 	 */
-	gcc_pure
+	[[gnu::pure]]
 	bool Contains(const MusicChunk *chunk) const noexcept;
 #endif
 
@@ -76,7 +75,7 @@ public:
 	 * Returns the first #MusicChunk from the pipe.  Returns
 	 * nullptr if the pipe is empty.
 	 */
-	gcc_pure
+	[[gnu::pure]]
 	const MusicChunk *Peek() const noexcept {
 		const std::lock_guard<Mutex> protect(mutex);
 		return head.get();
@@ -100,13 +99,13 @@ public:
 	/**
 	 * Returns the number of chunks currently in this pipe.
 	 */
-	gcc_pure
+	[[gnu::pure]]
 	unsigned GetSize() const noexcept {
 		const std::lock_guard<Mutex> protect(mutex);
 		return size;
 	}
 
-	gcc_pure
+	[[gnu::pure]]
 	bool IsEmpty() const noexcept {
 		return GetSize() == 0;
 	}

src/ReplayGainInfo.hxx

@@ -20,7 +20,6 @@
 #ifndef MPD_REPLAY_GAIN_INFO_HXX
 #define MPD_REPLAY_GAIN_INFO_HXX
 
-#include "util/Compiler.h"
 #include "ReplayGainMode.hxx"
 
 struct ReplayGainConfig;
@@ -42,7 +41,7 @@ struct ReplayGainTuple {
 		return {-200.0f, 0.0f};
 	}
 
-	gcc_pure
+	[[gnu::pure]]
 	float CalculateScale(const ReplayGainConfig &config) const noexcept;
 };
 

src/ReplayGainMode.cxx

@@ -18,6 +18,7 @@
  */
 
 #include "ReplayGainMode.hxx"
+#include "util/Compiler.h"
 
 #include <cassert>
 #include <stdexcept>

src/ReplayGainMode.hxx

@@ -20,8 +20,6 @@
 #ifndef MPD_REPLAY_GAIN_MODE_HXX
 #define MPD_REPLAY_GAIN_MODE_HXX
 
-#include "util/Compiler.h"
-
 #include <cstdint>
 
 enum class ReplayGainMode : uint8_t {
@@ -34,7 +32,7 @@ enum class ReplayGainMode : uint8_t {
 /**
  * Return the string representation of a #ReplayGainMode.
  */
-gcc_pure
+[[gnu::pure]]
 const char *
 ToString(ReplayGainMode mode) noexcept;
 

src/SingleMode.cxx

@@ -18,6 +18,7 @@
  */
 
 #include "SingleMode.hxx"
+#include "util/Compiler.h"
 
 #include <cassert>
 #include <stdexcept>

src/SingleMode.hxx

@@ -20,8 +20,6 @@
 #ifndef MPD_SINGLE_MODE_HXX
 #define MPD_SINGLE_MODE_HXX
 
-#include "util/Compiler.h"
-
 #include <cstdint>
 
 enum class SingleMode : uint8_t {
@@ -33,7 +31,7 @@ enum class SingleMode : uint8_t {
 /**
  * Return the string representation of a #SingleMode.
  */
-gcc_pure
+[[gnu::pure]]
 const char *
 SingleToString(SingleMode mode) noexcept;
 

src/SongLoader.hxx

@@ -20,7 +20,6 @@
 #ifndef MPD_SONG_LOADER_HXX
 #define MPD_SONG_LOADER_HXX
 
-#include "util/Compiler.h"
 #include "config.h"
 
 #include <cstddef>
@@ -72,14 +71,14 @@ public:
 	/**
 	 * Throws #std::runtime_error on error.
 	 */
-	gcc_nonnull_all
+	[[gnu::nonnull]]
 	DetachedSong LoadSong(const char *uri_utf8) const;
 
 private:
-	gcc_nonnull_all
+	[[gnu::nonnull]]
 	DetachedSong LoadFromDatabase(const char *uri) const;
 
-	gcc_nonnull_all
+	[[gnu::nonnull]]
 	DetachedSong LoadFile(const char *path_utf8, Path path_fs) const;
 };
 

src/StateFile.hxx

@@ -22,7 +22,6 @@
 
 #include "StateFileConfig.hxx"
 #include "event/FarTimerEvent.hxx"
-#include "util/Compiler.h"
 #include "config.h"
 
 #include <string>
@@ -76,7 +75,7 @@ private:
 	 * Check if MPD's state was modified since the last
 	 * RememberVersions() call.
 	 */
-	gcc_pure
+	[[gnu::pure]]
 	bool IsModified() const noexcept;
 
 	/* callback for #timer_event */

src/client/Client.hxx

@@ -27,7 +27,6 @@
 #include "tag/Mask.hxx"
 #include "event/FullyBufferedSocket.hxx"
 #include "event/CoarseTimerEvent.hxx"
-#include "util/Compiler.h"
 
 #include <boost/intrusive/link_mode.hpp>
 #include <boost/intrusive/list_hook.hpp>
@@ -138,7 +137,7 @@ public:
 	using FullyBufferedSocket::GetEventLoop;
 	using FullyBufferedSocket::GetOutputMaxSize;
 
-	gcc_pure
+	[[gnu::pure]]
 	bool IsExpired() const noexcept {
 		return !FullyBufferedSocket::IsDefined();
 	}
@@ -211,7 +210,7 @@ public:
 		FULL,
 	};
 
-	gcc_pure
+	[[gnu::pure]]
 	bool IsSubscribed(const char *channel_name) const noexcept {
 		return subscriptions.find(channel_name) != subscriptions.end();
 	}
@@ -252,19 +251,19 @@ public:
 
 	void SetPartition(Partition &new_partition) noexcept;
 
-	gcc_pure
+	[[gnu::pure]]
 	Instance &GetInstance() const noexcept;
 
-	gcc_pure
+	[[gnu::pure]]
 	playlist &GetPlaylist() const noexcept;
 
-	gcc_pure
+	[[gnu::pure]]
 	PlayerControl &GetPlayerControl() const noexcept;
 
 	/**
 	 * Wrapper for Instance::GetDatabase().
 	 */
-	gcc_pure
+	[[gnu::pure]]
 	const Database *GetDatabase() const noexcept;
 
 	/**
@@ -272,7 +271,7 @@ public:
 	 */
 	const Database &GetDatabaseOrThrow() const;
 
-	gcc_pure
+	[[gnu::pure]]
 	const Storage *GetStorage() const noexcept;
 
 private:

src/client/Message.hxx

@@ -20,8 +20,6 @@
 #ifndef MPD_CLIENT_MESSAGE_HXX
 #define MPD_CLIENT_MESSAGE_HXX
 
-#include "util/Compiler.h"
-
 #include <string>
 
 #ifdef _WIN32
@@ -51,7 +49,7 @@ public:
 	}
 };
 
-gcc_pure
+[[gnu::pure]]
 bool
 client_message_valid_channel_name(const char *name) noexcept;
 

src/command/NeighborCommands.hxx

@@ -21,14 +21,13 @@
 #define MPD_NEIGHBOR_COMMANDS_HXX
 
 #include "CommandResult.hxx"
-#include "util/Compiler.h"
 
 struct Instance;
 class Client;
 class Request;
 class Response;
 
-gcc_pure
+[[gnu::pure]]
 bool
 neighbor_commands_available(const Instance &instance) noexcept;
 

src/command/PlaylistCommands.hxx

@@ -21,13 +21,12 @@
 #define MPD_PLAYLIST_COMMANDS_HXX
 
 #include "CommandResult.hxx"
-#include "util/Compiler.h"
 
 class Client;
 class Request;
 class Response;
 
-gcc_const
+[[gnu::const]]
 bool
 playlist_commands_available() noexcept;
 

src/config/Block.hxx

@@ -20,8 +20,6 @@
 #ifndef MPD_CONFIG_BLOCK_HXX
 #define MPD_CONFIG_BLOCK_HXX
 
-#include "util/Compiler.h"
-
 #include <string>
 #include <vector>
 
@@ -39,7 +37,7 @@ struct BlockParam {
 	mutable bool used = false;
 
 	template<typename N, typename V>
-	gcc_nonnull_all
+	[[gnu::nonnull]]
 	BlockParam(N &&_name, V &&_value, int _line=-1) noexcept
 		:name(std::forward<N>(_name)), value(std::forward<V>(_value)),
 		 line(_line) {}
@@ -99,7 +97,7 @@ struct ConfigBlock {
 		return line < 0;
 	}
 
-	gcc_pure
+	[[gnu::pure]]
 	bool IsEmpty() const noexcept {
 		return block_params.empty();
 	}
@@ -109,17 +107,17 @@ struct ConfigBlock {
 	}
 
 	template<typename N, typename V>
-	gcc_nonnull_all
+	[[gnu::nonnull]]
 	void AddBlockParam(N &&_name, V &&_value, int _line=-1) noexcept {
 		block_params.emplace_back(std::forward<N>(_name),
 					  std::forward<V>(_value),
 					  _line);
 	}
 
-	gcc_nonnull_all gcc_pure
+	[[gnu::nonnull]] [[gnu::pure]]
 	const BlockParam *GetBlockParam(const char *_name) const noexcept;
 
-	gcc_pure
+	[[gnu::pure]]
 	const char *GetBlockValue(const char *name,
 				  const char *default_value=nullptr) const noexcept;
 

src/config/Data.hxx

@@ -46,7 +46,7 @@ struct ConfigData {
 
 	void AddParam(ConfigOption option, ConfigParam &&param) noexcept;
 
-	gcc_pure
+	[[gnu::pure]]
 	const ConfigParam *GetParam(ConfigOption option) const noexcept {
 		const auto &list = GetParamList(option);
 		return list.empty() ? nullptr : &list.front();
@@ -60,7 +60,7 @@ struct ConfigData {
 			: f(nullptr);
 	}
 
-	gcc_pure
+	[[gnu::pure]]
 	const char *GetString(ConfigOption option,
 			      const char *default_value=nullptr) const noexcept;
 
@@ -100,7 +100,7 @@ struct ConfigData {
 	ConfigBlock &AddBlock(ConfigBlockOption option,
 			      ConfigBlock &&block) noexcept;
 
-	gcc_pure
+	[[gnu::pure]]
 	const ConfigBlock *GetBlock(ConfigBlockOption option) const noexcept {
 		const auto &list = GetBlockList(option);
 		return list.empty() ? nullptr : &list.front();
@@ -115,7 +115,7 @@ struct ConfigData {
 	 * @param key the attribute name
 	 * @param value the expected attribute value
 	 */
-	gcc_pure
+	[[gnu::pure]]
 	const ConfigBlock *FindBlock(ConfigBlockOption option,
 				     const char *key, const char *value) const;
 

src/config/Option.hxx

@@ -102,14 +102,14 @@ enum class ConfigBlockOption {
 /**
  * @return #ConfigOption::MAX if not found
  */
-gcc_pure
+[[gnu::pure]]
 enum ConfigOption
 ParseConfigOptionName(const char *name) noexcept;
 
 /**
  * @return #ConfigOption::MAX if not found
  */
-gcc_pure
+[[gnu::pure]]
 enum ConfigBlockOption
 ParseConfigBlockOptionName(const char *name) noexcept;
 

src/config/Param.hxx

@@ -35,7 +35,7 @@ struct ConfigParam {
 		:line(_line) {}
 
 	template<typename V>
-	gcc_nonnull_all
+	[[gnu::nonnull]]
 	explicit ConfigParam(V &&_value, int _line=-1) noexcept
 		:value(std::forward<V>(_value)), line(_line) {}
 

src/db/DatabaseLock.hxx

@@ -27,7 +27,6 @@
 #define MPD_DB_LOCK_HXX
 
 #include "thread/Mutex.hxx"
-#include "util/Compiler.h"
 
 #include <cassert>
 
@@ -42,7 +41,7 @@ extern ThreadId db_mutex_holder;
 /**
  * Does the current thread hold the database lock?
  */
-gcc_pure
+[[gnu::pure]]
 static inline bool
 holding_db_lock() noexcept
 {

src/db/Interface.hxx

@@ -22,7 +22,6 @@
 
 #include "Visitor.hxx"
 #include "tag/Type.h"
-#include "util/Compiler.h"
 
 #include <chrono>
 #include <string>
@@ -136,7 +135,7 @@ public:
 	 * Returns the time stamp of the last database update.
 	 * Returns a negative value if that is not not known/available.
 	 */
-	gcc_pure
+	[[gnu::pure]]
 	virtual std::chrono::system_clock::time_point GetUpdateStamp() const noexcept = 0;
 };
 

src/db/LightDirectory.hxx

@@ -20,12 +20,9 @@
 #ifndef MPD_LIGHT_DIRECTORY_HXX
 #define MPD_LIGHT_DIRECTORY_HXX
 
-#include "util/Compiler.h"
+#include <chrono>
-
 #include <string>
 
-#include <time.h>
-
 struct Tag;
 
 /**
@@ -53,7 +50,7 @@ struct LightDirectory {
 		return *uri == 0;
 	}
 
-	gcc_pure
+	[[gnu::pure]]
 	const char *GetPath() const noexcept {
 		return uri;
 	}

src/db/PlaylistInfo.hxx

@@ -20,8 +20,6 @@
 #ifndef MPD_PLAYLIST_INFO_HXX
 #define MPD_PLAYLIST_INFO_HXX
 
-#include "util/Compiler.h"
-
 #include <string>
 #include <string_view>
 #include <chrono>
@@ -49,7 +47,7 @@ struct PlaylistInfo {
 		constexpr CompareName(std::string_view _name) noexcept
 			:name(_name) {}
 
-		gcc_pure
+		[[gnu::pure]]
 		bool operator()(const PlaylistInfo &pi) const noexcept {
 			return pi.name == name;
 		}

src/db/PlaylistVector.hxx

@@ -21,7 +21,6 @@
 #define MPD_PLAYLIST_VECTOR_HXX
 
 #include "db/PlaylistInfo.hxx"
-#include "util/Compiler.h"
 
 #include <list>
 #include <string_view>
@@ -31,7 +30,7 @@ protected:
 	/**
 	 * Caller must lock the #db_mutex.
 	 */
-	gcc_pure
+	[[gnu::pure]]
 	iterator find(std::string_view name) noexcept;
 
 public:

src/db/Registry.hxx

@@ -20,8 +20,6 @@
 #ifndef MPD_DATABASE_REGISTRY_HXX
 #define MPD_DATABASE_REGISTRY_HXX
 
-#include "util/Compiler.h"
-
 struct DatabasePlugin;
 
 /**
@@ -30,7 +28,7 @@ struct DatabasePlugin;
  */
 extern const DatabasePlugin *const database_plugins[];
 
-gcc_pure
+[[gnu::pure]]
 const DatabasePlugin *
 GetDatabasePluginByName(const char *name) noexcept;
 

src/db/Selection.hxx

@@ -22,7 +22,6 @@
 
 #include "protocol/RangeArg.hxx"
 #include "tag/Type.h"
-#include "util/Compiler.h"
 
 #include <string>
 
@@ -60,16 +59,16 @@ struct DatabaseSelection {
 	DatabaseSelection(const char *_uri, bool _recursive,
 			  const SongFilter *_filter=nullptr) noexcept;
 
-	gcc_pure
+	[[gnu::pure]]
 	bool IsEmpty() const noexcept;
 
 	/**
 	 * Does this selection contain constraints other than "base"?
 	 */
-	gcc_pure
+	[[gnu::pure]]
 	bool HasOtherThanBase() const noexcept;
 
-	gcc_pure
+	[[gnu::pure]]
 	bool Match(const LightSong &song) const noexcept;
 };
 

src/db/plugins/simple/Directory.hxx

@@ -21,7 +21,6 @@
 #define MPD_DIRECTORY_HXX
 
 #include "Ptr.hxx"
-#include "util/Compiler.h"
 #include "db/Visitor.hxx"
 #include "db/PlaylistVector.hxx"
 #include "db/Ptr.hxx"
@@ -113,7 +112,7 @@ public:
 	/**
 	 * Create a new root #Directory object.
 	 */
-	gcc_malloc gcc_returns_nonnull
+	[[gnu::malloc]] [[gnu::returns_nonnull]]
 	static Directory *NewRoot() noexcept {
 		return new Directory(std::string(), nullptr);
 	}
@@ -141,7 +140,7 @@ public:
 	 * (e.g. #DEVICE_PLAYLIST) and whether the underlying plugin
 	 * is available.
 	 */
-	gcc_pure
+	[[gnu::pure]]
 	bool IsPluginAvailable() const noexcept;
 
 	/**
@@ -164,10 +163,10 @@ public:
 	/**
 	 * Caller must lock the #db_mutex.
 	 */
-	gcc_pure
+	[[gnu::pure]]
 	const Directory *FindChild(std::string_view name) const noexcept;
 
-	gcc_pure
+	[[gnu::pure]]
 	Directory *FindChild(std::string_view name) noexcept {
 		const Directory *cthis = this;
 		return const_cast<Directory *>(cthis->FindChild(name));
@@ -211,20 +210,20 @@ public:
 	 *
 	 * @param uri the relative URI
 	 */
-	gcc_pure
+	[[gnu::pure]]
 	LookupResult LookupDirectory(std::string_view uri) noexcept;
 
 	[[gnu::pure]]
 	bool TargetExists(std::string_view target) const noexcept;
 
-	gcc_pure
+	[[gnu::pure]]
 	bool IsEmpty() const noexcept {
 		return children.empty() &&
 			songs.empty() &&
 			playlists.empty();
 	}
 
-	gcc_pure
+	[[gnu::pure]]
 	const char *GetPath() const noexcept {
 		return path.c_str();
 	}
@@ -232,13 +231,13 @@ public:
 	/**
 	 * Returns the base name of the directory.
 	 */
-	gcc_pure
+	[[gnu::pure]]
 	const char *GetName() const noexcept;
 
 	/**
 	 * Is this the root directory of the music database?
 	 */
-	gcc_pure
+	[[gnu::pure]]
 	bool IsRoot() const noexcept {
 		return parent == nullptr;
 	}
@@ -266,10 +265,10 @@ public:
 	 *
 	 * Caller must lock the #db_mutex.
 	 */
-	gcc_pure
+	[[gnu::pure]]
 	const Song *FindSong(std::string_view name_utf8) const noexcept;
 
-	gcc_pure
+	[[gnu::pure]]
 	Song *FindSong(std::string_view name_utf8) noexcept {
 		const Directory *cthis = this;
 		return const_cast<Song *>(cthis->FindSong(name_utf8));
@@ -307,7 +306,7 @@ public:
 		  const VisitDirectory& visit_directory, const VisitSong& visit_song,
 		  const VisitPlaylist& visit_playlist) const;
 
-	gcc_pure
+	[[gnu::pure]]
 	LightDirectory Export() const noexcept;
 };
 

src/db/plugins/simple/SimpleDatabasePlugin.hxx

@@ -25,7 +25,6 @@
 #include "db/Ptr.hxx"
 #include "fs/AllocatedPath.hxx"
 #include "util/Manual.hxx"
-#include "util/Compiler.h"
 #include "config.h"
 
 #include <cassert>
@@ -78,7 +77,7 @@ public:
 				  DatabaseListener &listener,
 				  const ConfigBlock &block);
 
-	gcc_pure
+	[[gnu::pure]]
 	Directory &GetRoot() noexcept {
 		assert(root != NULL);
 
@@ -98,7 +97,7 @@ public:
 	 * @param db the #Database to be mounted; must be "open"; on
 	 * success, this object gains ownership of the given #Database
 	 */
-	gcc_nonnull_all
+	[[gnu::nonnull]]
 	void Mount(const char *uri, DatabasePtr db);
 
 	/**
@@ -106,10 +105,10 @@ public:
 	 *
 	 * @return false if the mounted database needs to be updated
 	 */
-	gcc_nonnull_all
+	[[gnu::nonnull]]
 	bool Mount(const char *local_uri, const char *storage_uri);
 
-	gcc_nonnull_all
+	[[gnu::nonnull]]
 	bool Unmount(const char *uri) noexcept;
 
 	/* virtual methods from class Database */

src/db/plugins/simple/Song.hxx

@@ -24,7 +24,6 @@
 #include "Chrono.hxx"
 #include "tag/Tag.hxx"
 #include "pcm/AudioFormat.hxx"
-#include "util/Compiler.h"
 #include "config.h"
 
 #include <boost/intrusive/list.hpp>
@@ -108,14 +107,14 @@ struct Song {
 
 	Song(DetachedSong &&other, Directory &_parent) noexcept;
 
-	gcc_pure
+	[[gnu::pure]]
 	const char *GetFilenameSuffix() const noexcept;
 
 	/**
 	 * Checks whether the decoder plugin for this song is
 	 * available.
 	 */
-	gcc_pure
+	[[gnu::pure]]
 	bool IsPluginAvailable() const noexcept;
 
 	/**
@@ -149,10 +148,10 @@ struct Song {
 	 * Returns the URI of the song in UTF-8 encoding, including its
 	 * location within the music directory.
 	 */
-	gcc_pure
+	[[gnu::pure]]
 	std::string GetURI() const noexcept;
 
-	gcc_pure
+	[[gnu::pure]]
 	ExportedSong Export() const noexcept;
 };
 

src/db/plugins/upnp/Directory.cxx

@@ -33,7 +33,7 @@
 /* this destructor exists here just so it won't get inlined */
 UPnPDirContent::~UPnPDirContent() = default;
 
-gcc_pure
+[[gnu::pure]]
 static UPnPDirObject::ItemClass
 ParseItemClass(StringView name) noexcept
 {
@@ -45,7 +45,7 @@ ParseItemClass(StringView name) noexcept
 		return UPnPDirObject::ItemClass::UNKNOWN;
 }
 
-gcc_pure
+[[gnu::pure]]
 static SignedSongTime
 ParseDuration(const char *duration) noexcept
 {
@@ -73,7 +73,7 @@ ParseDuration(const char *duration) noexcept
  * elements. There is a very slight risk of collision in doing
  * this. Twonky returns directory names (titles) like 'Artist/Album'.
  */
-gcc_pure
+[[gnu::pure]]
 static std::string &&
 TitleToPathSegment(std::string &&s) noexcept
 {

src/db/plugins/upnp/Directory.hxx

@@ -21,7 +21,6 @@
 #define MPD_UPNP_DIRECTORY_HXX
 
 #include "Object.hxx"
-#include "util/Compiler.h"
 
 #include <string>
 #include <vector>
@@ -39,7 +38,7 @@ public:
 
 	~UPnPDirContent();
 
-	gcc_pure
+	[[gnu::pure]]
 	UPnPDirObject *FindObject(std::string_view name) noexcept {
 		for (auto &o : objects)
 			if (o.name == name)

src/db/plugins/upnp/Object.hxx

@@ -21,7 +21,6 @@
 #define MPD_UPNP_OBJECT_HXX
 
 #include "tag/Tag.hxx"
-#include "util/Compiler.h"
 
 #include <string>
 
@@ -89,12 +88,12 @@ public:
 		tag.Clear();
 	}
 
-	gcc_pure
+	[[gnu::pure]]
 	bool IsRoot() const noexcept {
 		return type == Type::CONTAINER && id == "0";
 	}
 
-	gcc_pure
+	[[gnu::pure]]
 	bool Check() const noexcept {
 		return !id.empty() &&
 			/* root nodes don't need a parent id and a

src/db/update/ExcludeList.hxx

@@ -25,7 +25,6 @@
 #ifndef MPD_EXCLUDE_H
 #define MPD_EXCLUDE_H
 
-#include "util/Compiler.h"
 #include "fs/Glob.hxx"
 #include "input/Ptr.hxx"
 #include "config.h"
@@ -50,7 +49,7 @@ public:
 	ExcludeList(const ExcludeList &_parent) noexcept
 		:parent(&_parent) {}
 
-	gcc_pure
+	[[gnu::pure]]
 	bool IsEmpty() const noexcept {
 #ifdef HAVE_CLASS_GLOB
 		return ((parent == nullptr) || parent->IsEmpty()) && patterns.empty();

src/db/update/Queue.hxx

@@ -20,8 +20,6 @@
 #ifndef MPD_UPDATE_QUEUE_HXX
 #define MPD_UPDATE_QUEUE_HXX
 
-#include "util/Compiler.h"
-
 #include <string>
 #include <string_view>
 #include <list>
@@ -61,7 +59,6 @@ class UpdateQueue {
 	std::list<UpdateQueueItem> update_queue;
 
 public:
-	gcc_nonnull_all
 	bool Push(SimpleDatabase &db, Storage &storage,
 		  std::string_view path, bool discard, unsigned id) noexcept;
 
@@ -71,10 +68,8 @@ public:
 		update_queue.clear();
 	}
 
-	gcc_nonnull_all
 	void Erase(SimpleDatabase &db) noexcept;
 
-	gcc_nonnull_all
 	void Erase(Storage &storage) noexcept;
 };
 

src/db/update/Service.hxx

@@ -24,7 +24,6 @@
 #include "Queue.hxx"
 #include "event/InjectEvent.hxx"
 #include "thread/Thread.hxx"
-#include "util/Compiler.h"
 
 #include <memory>
 #include <string_view>
@@ -90,7 +89,6 @@ public:
 	 * the whole music directory is updated
 	 * @return the job id
 	 */
-	gcc_nonnull_all
 	unsigned Enqueue(std::string_view path, bool discard);
 
 	/**

src/db/update/UpdateIO.hxx

@@ -20,8 +20,6 @@
 #ifndef MPD_UPDATE_IO_HXX
 #define MPD_UPDATE_IO_HXX
 
-#include "util/Compiler.h"
-
 #include <string_view>
 
 struct Directory;
@@ -43,11 +41,11 @@ GetInfo(Storage &storage, const char *uri_utf8, StorageFileInfo &info) noexcept;
 bool
 GetInfo(StorageDirectoryReader &reader, StorageFileInfo &info) noexcept;
 
-gcc_pure
+[[gnu::pure]]
 bool
 DirectoryExists(Storage &storage, const Directory &directory) noexcept;
 
-gcc_pure
+[[gnu::pure]]
 bool
 directory_child_is_regular(Storage &storage, const Directory &directory,
 			   std::string_view name_utf8) noexcept;
@@ -55,7 +53,7 @@ directory_child_is_regular(Storage &storage, const Directory &directory,
 /**
  * Checks if the given permissions on the mapped file are given.
  */
-gcc_pure
+[[gnu::pure]]
 bool
 directory_child_access(Storage &storage, const Directory &directory,
 		       std::string_view name, int mode) noexcept;

src/db/update/Walk.hxx

@@ -22,7 +22,6 @@
 
 #include "Config.hxx"
 #include "Editor.hxx"
-#include "util/Compiler.h"
 #include "config.h"
 
 #include <atomic>
@@ -76,7 +75,7 @@ public:
 	bool Walk(Directory &root, const char *path, bool discard) noexcept;
 
 private:
-	gcc_pure
+	[[gnu::pure]]
 	bool SkipSymlink(const Directory *directory,
 			 std::string_view utf8_name) const noexcept;
 

src/decoder/Bridge.hxx

@@ -132,7 +132,7 @@ public:
 	 *
 	 * Caller must lock the #DecoderControl object.
 	 */
-	gcc_pure
+	[[gnu::pure]]
 	bool CheckCancelRead() const noexcept;
 
 	/**

src/decoder/Client.hxx

@@ -23,7 +23,6 @@
 #include "Command.hxx"
 #include "Chrono.hxx"
 #include "input/Ptr.hxx"
-#include "util/Compiler.h"
 
 #include <cstdint>
 
@@ -57,7 +56,7 @@ public:
 	 * @return the current command, or DecoderCommand::NONE if there is no
 	 * command pending
 	 */
-	gcc_pure
+	[[gnu::pure]]
 	virtual DecoderCommand GetCommand() noexcept = 0;
 
 	/**
@@ -72,7 +71,7 @@ public:
 	 *
 	 * @return the destination position for the seek
 	 */
-	gcc_pure
+	[[gnu::pure]]
 	virtual SongTime GetSeekTime() noexcept = 0;
 
 	/**
@@ -80,7 +79,7 @@ public:
 	 *
 	 * @return the destination position for the seek in frames
 	 */
-	gcc_pure
+	[[gnu::pure]]
 	virtual uint64_t GetSeekFrame() noexcept = 0;
 
 	/**

src/decoder/Control.hxx

@@ -229,7 +229,7 @@ public:
 			state == DecoderState::ERROR;
 	}
 
-	gcc_pure
+	[[gnu::pure]]
 	bool LockIsIdle() const noexcept {
 		const std::lock_guard<Mutex> protect(mutex);
 		return IsIdle();
@@ -239,7 +239,7 @@ public:
 		return state == DecoderState::START;
 	}
 
-	gcc_pure
+	[[gnu::pure]]
 	bool LockIsStarting() const noexcept {
 		const std::lock_guard<Mutex> protect(mutex);
 		return IsStarting();
@@ -251,7 +251,7 @@ public:
 		return state == DecoderState::ERROR;
 	}
 
-	gcc_pure
+	[[gnu::pure]]
 	bool LockHasFailed() const noexcept {
 		const std::lock_guard<Mutex> protect(mutex);
 		return HasFailed();
@@ -307,15 +307,15 @@ public:
 	 *
 	 * Caller must lock the object.
 	 */
-	gcc_pure
+	[[gnu::pure]]
 	bool IsCurrentSong(const DetachedSong &_song) const noexcept;
 
-	gcc_pure
+	[[gnu::pure]]
 	bool IsUnseekableCurrentSong(const DetachedSong &_song) const noexcept {
 		return !seekable && IsCurrentSong(_song);
 	}
 
-	gcc_pure
+	[[gnu::pure]]
 	bool IsSeekableCurrentSong(const DetachedSong &_song) const noexcept {
 		return seekable && IsCurrentSong(_song);
 	}

src/decoder/DecoderBuffer.hxx

@@ -20,7 +20,6 @@
 #ifndef MPD_DECODER_BUFFER_HXX
 #define MPD_DECODER_BUFFER_HXX
 
-#include "util/Compiler.h"
 #include "util/DynamicFifoBuffer.hxx"
 #include "util/ConstBuffer.hxx"
 
@@ -74,7 +73,7 @@ public:
 	/**
 	 * How many bytes are stored in the buffer?
 	 */
-	gcc_pure
+	[[gnu::pure]]
 	size_t GetAvailable() const noexcept {
 		return buffer.GetAvailable();
 	}

src/decoder/DecoderList.hxx

@@ -20,8 +20,6 @@
 #ifndef MPD_DECODER_LIST_HXX
 #define MPD_DECODER_LIST_HXX
 
-#include "util/Compiler.h"
-
 #include <string_view>
 
 struct ConfigData;
@@ -32,7 +30,7 @@ extern bool decoder_plugins_enabled[];
 
 /* interface for using plugins */
 
-gcc_pure
+[[gnu::pure]]
 const struct DecoderPlugin *
 decoder_plugin_from_name(const char *name) noexcept;
 
@@ -98,7 +96,7 @@ decoder_plugins_for_each_enabled(F f)
  * Is there at least once #DecoderPlugin that supports the specified
  * file name suffix?
  */
-gcc_pure gcc_nonnull_all
+[[gnu::pure]]
 bool
 decoder_plugins_supports_suffix(std::string_view suffix) noexcept;
 

src/decoder/DecoderPlugin.hxx

@@ -20,8 +20,6 @@
 #ifndef MPD_DECODER_PLUGIN_HXX
 #define MPD_DECODER_PLUGIN_HXX
 
-#include "util/Compiler.h"
-
 #include <forward_list>  // IWYU pragma: export
 #include <set>
 #include <string>
@@ -246,19 +244,19 @@ struct DecoderPlugin {
 		return container_scan(path, tnum);
 	}
 
-	gcc_pure
+	[[gnu::pure]]
 	bool SupportsUri(const char *uri) const noexcept;
 
 	/**
 	 * Does the plugin announce the specified file name suffix?
 	 */
-	gcc_pure gcc_nonnull_all
+	[[gnu::pure]]
 	bool SupportsSuffix(std::string_view suffix) const noexcept;
 
 	/**
 	 * Does the plugin announce the specified MIME type?
 	 */
-	gcc_pure gcc_nonnull_all
+	[[gnu::pure]]
 	bool SupportsMimeType(std::string_view mime_type) const noexcept;
 
 	bool SupportsContainerSuffix(std::string_view suffix) const noexcept {

src/decoder/plugins/DsdLib.hxx

@@ -22,7 +22,6 @@
 
 #include "util/ByteOrder.hxx"
 #include "input/Offset.hxx"
-#include "util/Compiler.h"
 
 #include <cstdint>
 
@@ -33,7 +32,7 @@ class InputStream;
 struct DsdId {
 	char value[4];
 
-	gcc_pure
+	[[gnu::pure]]
 	bool Equals(const char *s) const noexcept;
 };
 
@@ -70,7 +69,7 @@ dsdlib_skip(DecoderClient *client, InputStream &is,
 /**
  * Check if the sample frequency is a valid DSD frequency.
  **/
-gcc_const
+[[gnu::const]]
 bool
 dsdlib_valid_freq(uint32_t samplefreq) noexcept;
 

src/filter/Registry.hxx

@@ -26,11 +26,9 @@
 #ifndef MPD_FILTER_REGISTRY_HXX
 #define MPD_FILTER_REGISTRY_HXX
 
-#include "util/Compiler.h"
-
 struct FilterPlugin;
 
-gcc_pure
+[[gnu::pure]]
 const FilterPlugin *
 filter_plugin_by_name(const char *name) noexcept;
 

src/fs/AllocatedPath.hxx

@@ -20,7 +20,6 @@
 #ifndef MPD_FS_ALLOCATED_PATH_HXX
 #define MPD_FS_ALLOCATED_PATH_HXX
 
-#include "util/Compiler.h"
 #include "Traits.hxx"
 #include "Path.hxx"
 
@@ -81,7 +80,7 @@ public:
 
 	~AllocatedPath() noexcept;
 
-	gcc_pure
+	[[gnu::pure]]
 	operator Path() const noexcept {
 		return Path::FromFS(c_str());
 	}
@@ -89,40 +88,40 @@ public:
 	/**
 	 * Join two path components with the path separator.
 	 */
-	gcc_pure
+	[[gnu::pure]]
 	static AllocatedPath Build(string_view a, string_view b) noexcept {
 		return AllocatedPath(Traits::Build(a, b));
 	}
 
-	gcc_pure gcc_nonnull_all
+	[[gnu::pure]]
 	static AllocatedPath Build(Path a, string_view b) noexcept {
 		return Build(a.c_str(), b);
 	}
 
-	gcc_pure gcc_nonnull_all
+	[[gnu::pure]]
 	static AllocatedPath Build(Path a, Path b) noexcept {
 		return Build(a, b.c_str());
 	}
 
-	gcc_pure gcc_nonnull_all
+	[[gnu::pure]]
 	static AllocatedPath Build(string_view a,
 				   const AllocatedPath &b) noexcept {
 		return Build(a, b.value);
 	}
 
-	gcc_pure gcc_nonnull_all
+	[[gnu::pure]]
 	static AllocatedPath Build(const AllocatedPath &a,
 				   string_view b) noexcept {
 		return Build(a.value, b);
 	}
 
-	gcc_pure
+	[[gnu::pure]]
 	static AllocatedPath Build(const AllocatedPath &a,
 				   const AllocatedPath &b) noexcept {
 		return Build(a.value, b.value);
 	}
 
-	gcc_pure
+	[[gnu::pure]]
 	static AllocatedPath Apply(Path base, Path path) noexcept {
 		return Traits::Apply(base.c_str(), path.c_str());
 	}
@@ -131,17 +130,17 @@ public:
 	 * Convert a C string that is already in the filesystem
 	 * character set to a #Path instance.
 	 */
-	gcc_pure
+	[[gnu::pure]]
 	static AllocatedPath FromFS(const_pointer fs) noexcept {
 		return AllocatedPath(fs);
 	}
 
-	gcc_pure
+	[[gnu::pure]]
 	static AllocatedPath FromFS(string_view fs) noexcept {
 		return AllocatedPath(fs);
 	}
 
-	gcc_pure
+	[[gnu::pure]]
 	static AllocatedPath FromFS(const_pointer _begin,
 				    const_pointer _end) noexcept {
 		return AllocatedPath(_begin, _end);
@@ -151,13 +150,13 @@ public:
 	 * Convert a C++ string that is already in the filesystem
 	 * character set to a #Path instance.
 	 */
-	gcc_pure
+	[[gnu::pure]]
 	static AllocatedPath FromFS(string &&fs) noexcept {
 		return AllocatedPath(std::move(fs));
 	}
 
 #ifdef ANDROID
-	gcc_pure
+	[[gnu::pure]]
 	static AllocatedPath FromUTF8(std::string &&utf8) noexcept {
 		/* on Android, the filesystem charset is hard-coded to
 		   UTF-8 */
@@ -173,7 +172,7 @@ public:
 	 * Convert a UTF-8 C string to an #AllocatedPath instance.
 	 * Returns return a "nulled" instance on error.
 	 */
-	gcc_pure
+	[[gnu::pure]]
 	static AllocatedPath FromUTF8(std::string_view path_utf8) noexcept;
 
 	static AllocatedPath FromUTF8(const char *path_utf8) noexcept {
@@ -199,12 +198,12 @@ public:
 		return *this;
 	}
 
-	gcc_pure
+	[[gnu::pure]]
 	bool operator==(const AllocatedPath &other) const noexcept {
 		return value == other.value;
 	}
 
-	gcc_pure
+	[[gnu::pure]]
 	bool operator!=(const AllocatedPath &other) const noexcept {
 		return value != other.value;
 	}
@@ -238,7 +237,7 @@ public:
 	 * @return the length of this string in number of "value_type"
 	 * elements (which may not be the number of characters).
 	 */
-	gcc_pure
+	[[gnu::pure]]
 	size_t length() const noexcept {
 		return value.length();
 	}
@@ -248,7 +247,7 @@ public:
 	 * pointer is invalidated whenever the value of life of this
 	 * instance ends.
 	 */
-	gcc_pure
+	[[gnu::pure]]
 	const_pointer c_str() const noexcept {
 		return value.c_str();
 	}
@@ -257,7 +256,7 @@ public:
 	 * Returns a pointer to the raw value, not necessarily
 	 * null-terminated.
 	 */
-	gcc_pure
+	[[gnu::pure]]
 	const_pointer data() const noexcept {
 		return value.data();
 	}
@@ -267,7 +266,7 @@ public:
 	 * Returns empty string on error or if this instance is "nulled"
 	 * (#IsNull returns true).
 	 */
-	gcc_pure
+	[[gnu::pure]]
 	std::string ToUTF8() const noexcept {
 		return ((Path)*this).ToUTF8();
 	}
@@ -280,7 +279,7 @@ public:
 	 * Gets directory name of this path.
 	 * Returns a "nulled" instance on error.
 	 */
-	gcc_pure
+	[[gnu::pure]]
 	AllocatedPath GetDirectoryName() const noexcept {
 		return ((Path)*this).GetDirectoryName();
 	}
@@ -291,12 +290,12 @@ public:
 	 * empty string if the given path equals this object or
 	 * nullptr on mismatch.
 	 */
-	gcc_pure
+	[[gnu::pure]]
 	const_pointer Relative(Path other_fs) const noexcept {
 		return Traits::Relative(c_str(), other_fs.c_str());
 	}
 
-	gcc_pure
+	[[gnu::pure]]
 	const_pointer GetSuffix() const noexcept {
 		return ((Path)*this).GetSuffix();
 	}
@@ -306,7 +305,7 @@ public:
 	 */
 	void ChopSeparators() noexcept;
 
-	gcc_pure
+	[[gnu::pure]]
 	bool IsAbsolute() const noexcept {
 		return Traits::IsAbsolute(c_str());
 	}

src/fs/Charset.hxx

@@ -20,13 +20,12 @@
 #ifndef MPD_FS_CHARSET_HXX
 #define MPD_FS_CHARSET_HXX
 
-#include "util/Compiler.h"
 #include "Traits.hxx"
 
 /**
  * Gets file system character set name.
  */
-gcc_const
+[[gnu::const]]
 const char *
 GetFSCharset() noexcept;
 

src/fs/Glob.hxx

@@ -30,8 +30,6 @@
 #endif
 
 #ifdef HAVE_CLASS_GLOB
-#include "util/Compiler.h"
-
 #include <string>
 
 /**
@@ -48,7 +46,7 @@ public:
 	Glob(Glob &&other) noexcept = default;
 	Glob &operator=(Glob &&other) noexcept = default;
 
-	gcc_pure
+	[[gnu::pure]]
 	bool Check(const char *name_fs) const noexcept;
 };
 

src/fs/Path.hxx

@@ -20,7 +20,6 @@
 #ifndef MPD_FS_PATH_HXX
 #define MPD_FS_PATH_HXX
 
-#include "util/Compiler.h"
 #include "Traits.hxx"
 
 #include <cassert>
@@ -88,7 +87,7 @@ public:
 	 * @return the length of this string in number of "value_type"
 	 * elements (which may not be the number of characters).
 	 */
-	gcc_pure
+	[[gnu::pure]]
 	size_t length() const noexcept {
 		assert(!IsNull());
 
@@ -117,7 +116,7 @@ public:
 	 * usually rejected by MPD because its protocol cannot
 	 * transfer newline characters).
 	 */
-	gcc_pure
+	[[gnu::pure]]
 	bool HasNewline() const noexcept {
 		return Traits::Find(c_str(), '\n') != nullptr;
 	}
@@ -127,7 +126,7 @@ public:
 	 * Returns empty string on error or if this instance is "nulled"
 	 * (#IsNull returns true).
 	 */
-	gcc_pure
+	[[gnu::pure]]
 	std::string ToUTF8() const noexcept;
 
 	/**
@@ -139,7 +138,7 @@ public:
 	 * Determine the "base" file name.
 	 * The return value points inside this object.
 	 */
-	gcc_pure
+	[[gnu::pure]]
 	Path GetBase() const noexcept {
 		return FromFS(Traits::GetBase(c_str()));
 	}
@@ -148,7 +147,7 @@ public:
 	 * Gets directory name of this path.
 	 * Returns a "nulled" instance on error.
 	 */
-	gcc_pure
+	[[gnu::pure]]
 	AllocatedPath GetDirectoryName() const noexcept;
 
 	/**
@@ -157,17 +156,17 @@ public:
 	 * empty string if the given path equals this object or
 	 * nullptr on mismatch.
 	 */
-	gcc_pure
+	[[gnu::pure]]
 	const_pointer Relative(Path other_fs) const noexcept {
 		return Traits::Relative(c_str(), other_fs.c_str());
 	}
 
-	gcc_pure
+	[[gnu::pure]]
 	bool IsAbsolute() const noexcept {
 		return Traits::IsAbsolute(c_str());
 	}
 
-	gcc_pure
+	[[gnu::pure]]
 	const_pointer GetSuffix() const noexcept;
 };
 

src/fs/StandardDirectory.hxx

@@ -37,7 +37,7 @@ GetUserMusicDir() noexcept;
 /**
  * Obtains cache directory for the current user.
  */
-gcc_pure
+[[gnu::pure]]
 AllocatedPath
 GetUserCacheDir() noexcept;
 

src/fs/Traits.hxx

@@ -71,7 +71,7 @@ struct PathTraitsFS {
 			ch == SEPARATOR;
 	}
 
-	gcc_pure gcc_nonnull_all
+	[[gnu::pure]] [[gnu::nonnull]]
 	static const_pointer FindLastSeparator(const_pointer p) noexcept {
 #if !CLANG_CHECK_VERSION(3,6)
 		/* disabled on clang due to -Wtautological-pointer-compare */
@@ -100,7 +100,7 @@ struct PathTraitsFS {
 #endif
 	}
 
-	gcc_pure
+	[[gnu::pure]]
 	static const_pointer GetFilenameSuffix(const_pointer filename) noexcept {
 		const_pointer dot = StringFindLast(filename, '.');
 		return dot != nullptr && dot > filename && dot[1] != 0
@@ -108,13 +108,13 @@ struct PathTraitsFS {
 			: nullptr;
 	}
 
-	gcc_pure
+	[[gnu::pure]]
 	static const_pointer GetPathSuffix(const_pointer path) noexcept {
 		return GetFilenameSuffix(GetBase(path));
 	}
 
 #ifdef _WIN32
-	gcc_pure gcc_nonnull_all
+	[[gnu::pure]] [[gnu::nonnull]]
 	static constexpr bool IsDrive(const_pointer p) noexcept {
 		return IsAlphaASCII(p[0]) && p[1] == ':';
 	}
@@ -124,7 +124,7 @@ struct PathTraitsFS {
 	}
 #endif
 
-	gcc_pure gcc_nonnull_all
+	[[gnu::pure]] [[gnu::nonnull]]
 	static bool IsAbsolute(const_pointer p) noexcept {
 #if !CLANG_CHECK_VERSION(3,6)
 		/* disabled on clang due to -Wtautological-pointer-compare */
@@ -138,18 +138,18 @@ struct PathTraitsFS {
 		return IsSeparator(*p);
 	}
 
-	gcc_pure gcc_nonnull_all
+	[[gnu::pure]] [[gnu::nonnull]]
 	static bool IsSpecialFilename(const_pointer name) noexcept {
 		return (name[0] == '.' && name[1] == 0) ||
 			(name[0] == '.' && name[1] == '.' && name[2] == 0);
 	}
 
-	gcc_pure gcc_nonnull_all
+	[[gnu::pure]] [[gnu::nonnull]]
 	static size_t GetLength(const_pointer p) noexcept {
 		return StringLength(p);
 	}
 
-	gcc_pure gcc_nonnull_all
+	[[gnu::pure]] [[gnu::nonnull]]
 	static const_pointer Find(const_pointer p, value_type ch) noexcept {
 		return StringFind(p, ch);
 	}
@@ -158,7 +158,7 @@ struct PathTraitsFS {
 	 * Determine the "base" file name of the given native path.
 	 * The return value points inside the given string.
 	 */
-	gcc_pure gcc_nonnull_all
+	[[gnu::pure]] [[gnu::nonnull]]
 	static const_pointer GetBase(const_pointer p) noexcept;
 
 	/**
@@ -166,7 +166,7 @@ struct PathTraitsFS {
 	 * As a special case, returns the string "." if there is no
 	 * separator in the given input string.
 	 */
-	gcc_pure gcc_nonnull_all
+	[[gnu::pure]] [[gnu::nonnull]]
 	static string_view GetParent(const_pointer p) noexcept;
 
 	[[gnu::pure]]
@@ -178,10 +178,10 @@ struct PathTraitsFS {
 	 * empty string if the given path equals this object or
 	 * nullptr on mismatch.
 	 */
-	gcc_pure gcc_nonnull_all
+	[[gnu::pure]] [[gnu::nonnull]]
 	static const_pointer Relative(string_view base, const_pointer other) noexcept;
 
-	gcc_pure
+	[[gnu::pure]]
 	static string_view Relative(string_view base, string_view other) noexcept;
 
 	/**
@@ -190,14 +190,14 @@ struct PathTraitsFS {
 	 * remaining component is returned unchanged.
 	 * If both components are empty strings, empty string is returned.
 	 */
-	gcc_pure
+	[[gnu::pure]]
 	static string Build(string_view a, string_view b) noexcept;
 
 	/**
 	 * Interpret the given path as being relative to the given
 	 * base, and return the concatenated path.
 	 */
-	gcc_pure
+	[[gnu::pure]]
 	static string Apply(const_pointer base,
 			    const_pointer path) noexcept;
 };
@@ -221,7 +221,7 @@ struct PathTraitsUTF8 {
 		return ch == SEPARATOR;
 	}
 
-	gcc_pure gcc_nonnull_all
+	[[gnu::pure]] [[gnu::nonnull]]
 	static const_pointer FindLastSeparator(const_pointer p) noexcept {
 #if !CLANG_CHECK_VERSION(3,6)
 		/* disabled on clang due to -Wtautological-pointer-compare */
@@ -236,7 +236,7 @@ struct PathTraitsUTF8 {
 		return StringFindLast(p.data(), SEPARATOR, p.size());
 	}
 
-	gcc_pure
+	[[gnu::pure]]
 	static const_pointer GetFilenameSuffix(const_pointer filename) noexcept {
 		const_pointer dot = StringFindLast(filename, '.');
 		return dot != nullptr && dot > filename && dot[1] != 0
@@ -244,13 +244,13 @@ struct PathTraitsUTF8 {
 			: nullptr;
 	}
 
-	gcc_pure
+	[[gnu::pure]]
 	static const_pointer GetPathSuffix(const_pointer path) noexcept {
 		return GetFilenameSuffix(GetBase(path));
 	}
 
 #ifdef _WIN32
-	gcc_pure gcc_nonnull_all
+	[[gnu::pure]] [[gnu::nonnull]]
 	static constexpr bool IsDrive(const_pointer p) noexcept {
 		return IsAlphaASCII(p[0]) && p[1] == ':';
 	}
@@ -260,7 +260,7 @@ struct PathTraitsUTF8 {
 	}
 #endif
 
-	gcc_pure gcc_nonnull_all
+	[[gnu::pure]] [[gnu::nonnull]]
 	static bool IsAbsolute(const_pointer p) noexcept {
 #if !CLANG_CHECK_VERSION(3,6)
 		/* disabled on clang due to -Wtautological-pointer-compare */
@@ -281,18 +281,18 @@ struct PathTraitsUTF8 {
 	[[gnu::pure]] [[gnu::nonnull]]
 	static bool IsAbsoluteOrHasScheme(const_pointer p) noexcept;
 
-	gcc_pure gcc_nonnull_all
+	[[gnu::pure]] [[gnu::nonnull]]
 	static bool IsSpecialFilename(const_pointer name) noexcept {
 		return (name[0] == '.' && name[1] == 0) ||
 			(name[0] == '.' && name[1] == '.' && name[2] == 0);
 	}
 
-	gcc_pure gcc_nonnull_all
+	[[gnu::pure]] [[gnu::nonnull]]
 	static size_t GetLength(const_pointer p) noexcept {
 		return StringLength(p);
 	}
 
-	gcc_pure gcc_nonnull_all
+	[[gnu::pure]] [[gnu::nonnull]]
 	static const_pointer Find(const_pointer p, value_type ch) noexcept {
 		return StringFind(p, ch);
 	}
@@ -301,7 +301,7 @@ struct PathTraitsUTF8 {
 	 * Determine the "base" file name of the given UTF-8 path.
 	 * The return value points inside the given string.
 	 */
-	gcc_pure gcc_nonnull_all
+	[[gnu::pure]] [[gnu::nonnull]]
 	static const_pointer GetBase(const_pointer p) noexcept;
 
 	/**
@@ -309,7 +309,7 @@ struct PathTraitsUTF8 {
 	 * As a special case, returns the string "." if there is no
 	 * separator in the given input string.
 	 */
-	gcc_pure gcc_nonnull_all
+	[[gnu::pure]] [[gnu::nonnull]]
 	static string_view GetParent(const_pointer p) noexcept;
 
 	[[gnu::pure]]
@@ -321,10 +321,10 @@ struct PathTraitsUTF8 {
 	 * empty string if the given path equals this object or
 	 * nullptr on mismatch.
 	 */
-	gcc_pure gcc_nonnull_all
+	[[gnu::pure]] [[gnu::nonnull]]
 	static const_pointer Relative(string_view base, const_pointer other) noexcept;
 
-	gcc_pure
+	[[gnu::pure]]
 	static string_view Relative(string_view base, string_view other) noexcept;
 
 	/**
@@ -333,7 +333,7 @@ struct PathTraitsUTF8 {
 	 * remaining component is returned unchanged.
 	 * If both components are empty strings, empty string is returned.
 	 */
-	gcc_pure
+	[[gnu::pure]]
 	static string Build(string_view a, string_view b) noexcept;
 };
 

src/fs/io/AutoGunzipReader.cxx

@@ -25,7 +25,7 @@ AutoGunzipReader::AutoGunzipReader(Reader &_next) noexcept
 
 AutoGunzipReader::~AutoGunzipReader() noexcept = default;
 
-gcc_pure
+[[gnu::pure]]
 static bool
 IsGzip(const uint8_t data[4]) noexcept
 {

src/fs/io/BufferedReader.hxx

@@ -30,7 +30,6 @@
 #ifndef BUFFERED_READER_HXX
 #define BUFFERED_READER_HXX
 
-#include "util/Compiler.h"
 #include "util/DynamicFifoBuffer.hxx"
 
 #include <cstddef>
@@ -64,7 +63,7 @@ public:
 
 	bool Fill(bool need_more);
 
-	gcc_pure
+	[[gnu::pure]]
 	WritableBuffer<void> Read() const noexcept {
 		return buffer.Read().ToVoid();
 	}

src/fs/io/FileOutputStream.hxx

@@ -32,7 +32,6 @@
 
 #include "OutputStream.hxx"
 #include "fs/AllocatedPath.hxx"
-#include "util/Compiler.h"
 
 #ifndef _WIN32
 #include "io/FileDescriptor.hxx"
@@ -133,7 +132,7 @@ public:
 		return path;
 	}
 
-	gcc_pure
+	[[gnu::pure]]
 	uint64_t Tell() const noexcept;
 
 	/* virtual methods from class OutputStream */

src/fs/io/FileReader.hxx

@@ -32,7 +32,6 @@
 
 #include "Reader.hxx"
 #include "fs/AllocatedPath.hxx"
-#include "util/Compiler.h"
 
 #ifdef _WIN32
 #include <fileapi.h>
@@ -94,7 +93,7 @@ public:
 
 	FileInfo GetFileInfo() const;
 
-	gcc_pure
+	[[gnu::pure]]
 	uint64_t GetSize() const noexcept {
 #ifdef _WIN32
 		LARGE_INTEGER size;
@@ -106,7 +105,7 @@ public:
 #endif
 	}
 
-	gcc_pure
+	[[gnu::pure]]
 	uint64_t GetPosition() const noexcept {
 #ifdef _WIN32
 		LARGE_INTEGER zero;

src/fs/io/Reader.hxx

@@ -30,8 +30,6 @@
 #ifndef READER_HXX
 #define READER_HXX
 
-#include "util/Compiler.h"
-
 #include <cstddef>
 
 /**
@@ -52,7 +50,7 @@ public:
 	 * @return the number of bytes read into the given buffer or 0
 	 * on end-of-stream
 	 */
-	gcc_nonnull_all
+	[[gnu::nonnull]]
 	virtual size_t Read(void *data, size_t size) = 0;
 };
 

src/input/AsyncInputStream.hxx

@@ -123,7 +123,7 @@ protected:
 	/**
 	 * Determine how many bytes can be added to the buffer.
 	 */
-	gcc_pure
+	[[gnu::pure]]
 	size_t GetBufferSpace() const noexcept {
 		return buffer.GetSpace();
 	}

src/input/Error.hxx

@@ -20,8 +20,6 @@
 #ifndef INPUT_ERROR_HXX
 #define INPUT_ERROR_HXX
 
-#include "util/Compiler.h"
-
 #include <exception>
 
 /**
@@ -29,7 +27,7 @@
  * exist?  This function attempts to recognize exceptions thrown by
  * various input plugins.
  */
-gcc_pure
+[[gnu::pure]]
 bool
 IsFileNotFound(std::exception_ptr e) noexcept;
 

src/input/IcyInputStream.hxx

@@ -21,7 +21,6 @@
 #define MPD_ICY_INPUT_STREAM_HXX
 
 #include "ProxyInputStream.hxx"
-#include "util/Compiler.h"
 
 #include <memory>
 
@@ -63,7 +62,7 @@ public:
 	IcyInputStream(const IcyInputStream &) = delete;
 	IcyInputStream &operator=(const IcyInputStream &) = delete;
 
-	gcc_pure
+	[[gnu::pure]]
 	bool IsEnabled() const noexcept;
 
 	/* virtual methods from InputStream */

src/input/InputPlugin.hxx

@@ -22,7 +22,6 @@
 
 #include "Ptr.hxx"
 #include "thread/Mutex.hxx"
-#include "util/Compiler.h"
 
 #include <cassert>
 #include <set>
@@ -83,7 +82,7 @@ struct InputPlugin {
 	std::unique_ptr<RemoteTagScanner> (*scan_tags)(const char *uri,
 						       RemoteTagHandler &handler) = nullptr;
 
-	gcc_pure
+	[[gnu::pure]]
 	bool SupportsUri(const char *uri) const noexcept;
 
 	template<typename F>
@@ -103,7 +102,7 @@ struct InputPlugin {
 	}
 };
 
-gcc_pure
+[[gnu::pure]]
 bool
 protocol_is_whitelisted(const char *proto) noexcept;
 

src/input/InputStream.hxx

@@ -23,7 +23,6 @@
 #include "Offset.hxx"
 #include "Ptr.hxx"
 #include "thread/Mutex.hxx"
-#include "util/Compiler.h"
 
 #include <cassert>
 #include <memory>
@@ -123,14 +122,12 @@ public:
 	 * notifications
 	 * @return an #InputStream object on success
 	 */
-	gcc_nonnull(1)
 	static InputStreamPtr Open(const char *uri, Mutex &mutex);
 
 	/**
 	 * Just like Open(), but waits for the stream to become ready.
 	 * It is a wrapper for Open(), WaitReady() and Check().
 	 */
-	gcc_nonnull(1)
 	static InputStreamPtr OpenReady(const char *uri, Mutex &mutex);
 
 	/**
@@ -184,14 +181,14 @@ public:
 		return ready;
 	}
 
-	gcc_pure
+	[[gnu::pure]]
 	bool HasMimeType() const noexcept {
 		assert(ready);
 
 		return !mime.empty();
 	}
 
-	gcc_pure
+	[[gnu::pure]]
 	const char *GetMimeType() const noexcept {
 		assert(ready);
 
@@ -202,7 +199,7 @@ public:
 		mime.clear();
 	}
 
-	gcc_nonnull_all
+	[[gnu::nonnull]]
 	void SetMimeType(const char *_mime) noexcept {
 		assert(!ready);
 
@@ -215,14 +212,14 @@ public:
 		mime = std::move(_mime);
 	}
 
-	gcc_pure
+	[[gnu::pure]]
 	bool KnownSize() const noexcept {
 		assert(ready);
 
 		return size != UNKNOWN_SIZE;
 	}
 
-	gcc_pure
+	[[gnu::pure]]
 	offset_type GetSize() const noexcept {
 		assert(ready);
 		assert(KnownSize());
@@ -236,14 +233,14 @@ public:
 		offset += delta;
 	}
 
-	gcc_pure
+	[[gnu::pure]]
 	offset_type GetOffset() const noexcept {
 		assert(ready);
 
 		return offset;
 	}
 
-	gcc_pure
+	[[gnu::pure]]
 	offset_type GetRest() const noexcept {
 		assert(ready);
 		assert(KnownSize());
@@ -251,7 +248,7 @@ public:
 		return size - offset;
 	}
 
-	gcc_pure
+	[[gnu::pure]]
 	bool IsSeekable() const noexcept {
 		assert(ready);
 
@@ -261,7 +258,7 @@ public:
 	/**
 	 * Determines whether seeking is cheap.  This is true for local files.
 	 */
-	gcc_pure
+	[[gnu::pure]]
 	bool CheapSeeking() const noexcept;
 
 	/**
@@ -313,14 +310,14 @@ public:
 	 *
 	 * The caller must lock the mutex.
 	 */
-	gcc_pure
+	[[gnu::pure]]
 	virtual bool IsEOF() const noexcept = 0;
 
 	/**
 	 * Wrapper for IsEOF() which locks and unlocks the mutex; the
 	 * caller must not be holding it already.
 	 */
-	gcc_pure
+	[[gnu::pure]]
 	bool LockIsEOF() const noexcept;
 
 	/**
@@ -346,7 +343,7 @@ public:
 	 *
 	 * The caller must lock the mutex.
 	 */
-	gcc_pure
+	[[gnu::pure]]
 	virtual bool IsAvailable() const noexcept;
 
 	/**
@@ -363,7 +360,7 @@ public:
 	 * @param size the maximum number of bytes to read
 	 * @return the number of bytes read
 	 */
-	gcc_nonnull_all
+	[[gnu::nonnull]]
 	virtual size_t Read(std::unique_lock<Mutex> &lock,
 			    void *ptr, size_t size) = 0;
 
@@ -373,7 +370,7 @@ public:
 	 *
 	 * Throws std::runtime_error on error.
 	 */
-	gcc_nonnull_all
+	[[gnu::nonnull]]
 	size_t LockRead(void *ptr, size_t size);
 
 	/**
@@ -387,7 +384,7 @@ public:
 	 * @param size the number of bytes to read
 	 * @return true if the whole data was read, false otherwise.
 	 */
-	gcc_nonnull_all
+	[[gnu::nonnull]]
 	void ReadFull(std::unique_lock<Mutex> &lock, void *ptr, size_t size);
 
 	/**
@@ -396,7 +393,7 @@ public:
 	 *
 	 * Throws std::runtime_error on error.
 	 */
-	gcc_nonnull_all
+	[[gnu::nonnull]]
 	void LockReadFull(void *ptr, size_t size);
 
 protected:

src/input/Registry.hxx

@@ -20,8 +20,6 @@
 #ifndef MPD_INPUT_REGISTRY_HXX
 #define MPD_INPUT_REGISTRY_HXX
 
-#include "util/Compiler.h"
-
 /**
  * NULL terminated list of all input plugins which were enabled at
  * compile time.
@@ -40,7 +38,7 @@ extern bool input_plugins_enabled[];
 	input_plugins_for_each(plugin) \
 		if (input_plugins_enabled[input_plugin_iterator - input_plugins])
 
-gcc_pure
+[[gnu::pure]]
 bool
 HasRemoteTagScanner(const char *uri) noexcept;
 

src/input/cache/Manager.hxx

@@ -21,7 +21,6 @@
 #define MPD_INPUT_CACHE_MANAGER_HXX
 
 #include "thread/Mutex.hxx"
-#include "util/Compiler.h"
 
 #include <boost/intrusive/set.hpp>
 #include <boost/intrusive/list.hpp>
@@ -43,15 +42,15 @@ class InputCacheManager {
 	size_t total_size = 0;
 
 	struct ItemCompare {
-		gcc_pure
+		[[gnu::pure]]
 		bool operator()(const InputCacheItem &a,
 				const char *b) const noexcept;
 
-		gcc_pure
+		[[gnu::pure]]
 		bool operator()(const char *a,
 				const InputCacheItem &b) const noexcept;
 
-		gcc_pure
+		[[gnu::pure]]
 		bool operator()(const InputCacheItem &a,
 				const InputCacheItem &b) const noexcept;
 	};
@@ -74,7 +73,7 @@ public:
 
 	void Flush() noexcept;
 
-	gcc_pure
+	[[gnu::pure]]
 	bool Contains(const char *uri) noexcept;
 
 	/**

src/input/plugins/FfmpegInputPlugin.cxx

@@ -55,7 +55,7 @@ public:
 		  offset_type offset) override;
 };
 
-gcc_const
+[[gnu::const]]
 static inline bool
 input_ffmpeg_supported() noexcept
 {

src/input/plugins/QobuzClient.hxx

@@ -77,7 +77,7 @@ public:
 		return format_id;
 	}
 
-	gcc_pure
+	[[gnu::pure]]
 	CurlGlobal &GetCurl() noexcept;
 
 	void AddLoginHandler(QobuzSessionHandler &h) noexcept;

src/input/plugins/QobuzInputPlugin.cxx

@@ -166,7 +166,7 @@ FinishQobuzInput() noexcept
 	delete qobuz_client;
 }
 
-gcc_pure
+[[gnu::pure]]
 static const char *
 ExtractQobuzTrackId(const char *uri)
 {

src/java/File.hxx

@@ -48,10 +48,10 @@ class File : public LocalObject {
 public:
 	using LocalObject::LocalObject;
 
-	gcc_nonnull_all
+	[[gnu::nonnull]]
 	static void Initialise(JNIEnv *env) noexcept;
 
-	gcc_nonnull_all
+	[[gnu::nonnull]]
 	static jstring GetAbsolutePath(JNIEnv *env, jobject file) noexcept {
 		return (jstring)env->CallObjectMethod(file,
 						      getAbsolutePath_method);
@@ -69,7 +69,7 @@ public:
 	 * Invoke File.getAbsolutePath() and release the
 	 * specified File reference.
 	 */
-	gcc_pure gcc_nonnull_all
+	[[gnu::pure]] [[gnu::nonnull]]
 	static AllocatedPath ToAbsolutePath(JNIEnv *env,
 					    jobject file) noexcept;
 };

src/java/Global.hxx

@@ -30,8 +30,6 @@
 #ifndef JAVA_GLOBAL_HXX
 #define JAVA_GLOBAL_HXX
 
-#include "util/Compiler.h"
-
 #include <jni.h>
 
 namespace Java {
@@ -47,8 +45,9 @@ DetachCurrentThread() noexcept
 		jvm->DetachCurrentThread();
 }
 
-static inline gcc_pure
+[[gnu::pure]]
-JNIEnv *GetEnv() noexcept
+static inline JNIEnv *
+GetEnv() noexcept
 {
 	JNIEnv *env;
 	jvm->AttachCurrentThread(&env, nullptr);

src/lib/alsa/Format.hxx

@@ -43,7 +43,7 @@
  * enum.  Returns SND_PCM_FORMAT_UNKNOWN if there is no according ALSA
  * PCM format.
  */
-gcc_const
+[[gnu::const]]
 inline snd_pcm_format_t
 ToAlsaPcmFormat(SampleFormat sample_format) noexcept
 {
@@ -82,7 +82,7 @@ ToAlsaPcmFormat(SampleFormat sample_format) noexcept
  * Determine the byte-swapped PCM format.  Returns
  * SND_PCM_FORMAT_UNKNOWN if the format cannot be byte-swapped.
  */
-gcc_const
+[[gnu::const]]
 inline snd_pcm_format_t
 ByteSwapAlsaPcmFormat(snd_pcm_format_t fmt) noexcept
 {
@@ -123,8 +123,7 @@ ByteSwapAlsaPcmFormat(snd_pcm_format_t fmt) noexcept
  * Check if there is a "packed" version of the give PCM format.
  * Returns SND_PCM_FORMAT_UNKNOWN if not.
  */
-gcc_const
+constexpr snd_pcm_format_t
-inline snd_pcm_format_t
 PackAlsaPcmFormat(snd_pcm_format_t fmt) noexcept
 {
 	switch (fmt) {

src/lib/alsa/Version.cxx

@@ -23,7 +23,7 @@
 
 #include <stdlib.h>
 
-gcc_pure
+[[gnu::pure]]
 static uint_least32_t
 ParseAlsaVersion(const char *p) noexcept
 {

src/lib/alsa/Version.hxx

@@ -20,8 +20,6 @@
 #ifndef MPD_ALSA_VERSION_HXX
 #define MPD_ALSA_VERSION_HXX
 
-#include "util/Compiler.h"
-
 #include <cstdint>
 
 static constexpr uint_least32_t
@@ -35,7 +33,7 @@ MakeAlsaVersion(uint_least32_t major, uint_least32_t minor,
  * Wrapper for snd_asoundlib_version() which translates the resulting
  * string to an integer constructed with MakeAlsaVersion().
  */
-gcc_const
+[[gnu::const]]
 uint_least32_t
 GetRuntimeAlsaVersion() noexcept;
 

src/lib/cdio/Paranoia.hxx

@@ -31,7 +31,6 @@
 #define CDIO_PARANOIA_HXX
 
 #include "util/ConstBuffer.hxx"
-#include "util/Compiler.h"
 
 #include <cdio/version.h>
 #include <cdio/paranoia/paranoia.h>
@@ -88,7 +87,7 @@ public:
 		return std::pair(first, last);
 	}
 
-	gcc_pure
+	[[gnu::pure]]
 	bool IsAudioTrack(track_t i) const noexcept {
 		return cdio_cddap_track_audiop(drv, i);
 	}
@@ -101,7 +100,7 @@ public:
 		return std::pair(first, last);
 	}
 
-	gcc_pure
+	[[gnu::pure]]
 	unsigned GetTrackCount() const noexcept {
 		return cdio_cddap_tracks(drv);
 	}

src/lib/crypto/MD5.hxx

@@ -31,7 +31,6 @@
 #define MD5_HXX
 
 #include "util/StringBuffer.hxx"
-#include "util/Compiler.h"
 
 #include <array>
 #include <cstdint>
@@ -41,11 +40,11 @@ template<typename T> struct ConstBuffer;
 void
 GlobalInitMD5() noexcept;
 
-gcc_pure
+[[gnu::pure]]
 std::array<uint8_t, 16>
 MD5(ConstBuffer<void> input) noexcept;
 
-gcc_pure
+[[gnu::pure]]
 StringBuffer<33>
 MD5Hex(ConstBuffer<void> input) noexcept;
 

src/lib/curl/Easy.hxx

@@ -1,5 +1,5 @@
 /*
- * Copyright 2016-2018 Max Kellermann <max.kellermann@gmail.com>
+ * Copyright 2016-2021 Max Kellermann <max.kellermann@gmail.com>
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
@@ -31,7 +31,6 @@
 #define CURL_EASY_HXX
 
 #include "String.hxx"
-#include "util/Compiler.h"
 
 #include <curl/curl.h>
 
@@ -199,7 +198,7 @@ public:
 	/**
 	 * Returns the response body's size, or -1 if that is unknown.
 	 */
-	gcc_pure
+	[[gnu::pure]]
 	int64_t GetContentLength() const noexcept {
 		double value;
 		return GetInfo(CURLINFO_CONTENT_LENGTH_DOWNLOAD, &value)

src/lib/curl/Global.cxx

@@ -31,6 +31,7 @@
 #include "Request.hxx"
 #include "event/Loop.hxx"
 #include "event/SocketEvent.hxx"
+#include "util/Compiler.h"
 
 #include <cassert>
 
@@ -84,7 +85,7 @@ private:
 			(flags & SocketEvent::ERROR ? CURL_CSELECT_ERR : 0);
 	}
 
-	gcc_const
+	[[gnu::const]]
 	static unsigned CurlPollToFlags(int action) noexcept {
 		switch (action) {
 		case CURL_POLL_NONE:
@@ -172,7 +173,7 @@ CurlGlobal::Remove(CurlRequest &r) noexcept
 /**
  * Find a request by its CURL "easy" handle.
  */
-gcc_pure
+[[gnu::pure]]
 static CurlRequest *
 ToRequest(CURL *easy) noexcept
 {

src/lib/curl/Request.cxx

@@ -172,7 +172,7 @@ CurlRequest::Done(CURLcode result) noexcept
 	}
 }
 
-gcc_pure
+[[gnu::pure]]
 static bool
 IsResponseBoundaryHeader(StringView s) noexcept
 {

src/lib/curl/Version.hxx

@@ -30,9 +30,7 @@
 #ifndef CURL_VERSION_HXX
 #define CURL_VERSION_HXX
 
-#include "util/Compiler.h"
+[[gnu::const]]
-
-gcc_const
 bool
 IsCurlOlderThan(unsigned version_num) noexcept;
 

src/lib/dbus/Error.hxx

@@ -33,8 +33,6 @@
 #ifndef ODBUS_ERROR_HXX
 #define ODBUS_ERROR_HXX
 
-#include "util/Compiler.h"
-
 #include <dbus/dbus.h>
 
 namespace ODBus {
@@ -54,7 +52,7 @@ public:
 	Error(const Error &) = delete;
 	Error &operator=(const Error &) = delete;
 
-	gcc_pure
+	[[gnu::pure]]
 	operator bool() const noexcept {
 		return dbus_error_is_set(&error);
 	}

src/lib/expat/ExpatParser.hxx

@@ -20,8 +20,6 @@
 #ifndef MPD_EXPAT_HXX
 #define MPD_EXPAT_HXX
 
-#include "util/Compiler.h"
-
 #include <expat.h>
 
 #include <stdexcept>
@@ -80,11 +78,11 @@ public:
 
 	void Parse(InputStream &is);
 
-	gcc_pure
+	[[gnu::pure]]
 	static const char *GetAttribute(const XML_Char **atts,
 					const char *name) noexcept;
 
-	gcc_pure
+	[[gnu::pure]]
 	static const char *GetAttributeCase(const XML_Char **atts,
 					    const char *name) noexcept;
 };
@@ -117,13 +115,13 @@ public:
 		parser.CompleteParse();
 	}
 
-	gcc_pure
+	[[gnu::pure]]
 	static const char *GetAttribute(const XML_Char **atts,
 					const char *name) noexcept {
 		return ExpatParser::GetAttribute(atts, name);
 	}
 
-	gcc_pure
+	[[gnu::pure]]
 	static const char *GetAttributeCase(const XML_Char **atts,
 					    const char *name) noexcept {
 		return ExpatParser::GetAttributeCase(atts, name);

src/lib/ffmpeg/Buffer.hxx

@@ -20,8 +20,6 @@
 #ifndef MPD_FFMPEG_BUFFER_HXX
 #define MPD_FFMPEG_BUFFER_HXX
 
-#include "util/Compiler.h"
-
 extern "C" {
 #include <libavutil/mem.h>
 }
@@ -42,7 +40,7 @@ public:
 	FfmpegBuffer(const FfmpegBuffer &) = delete;
 	FfmpegBuffer &operator=(const FfmpegBuffer &) = delete;
 
-	gcc_malloc
+	[[gnu::malloc]]
 	void *Get(size_t min_size) noexcept {
 		av_fast_malloc(&data, &size, min_size);
 		return data;

src/lib/ffmpeg/IOContext.hxx

@@ -20,7 +20,6 @@
 #ifndef MPD_FFMPEG_IO_CONTEXT_HXX
 #define MPD_FFMPEG_IO_CONTEXT_HXX
 
-#include "util/Compiler.h"
 #include "Error.hxx"
 
 extern "C" {
@@ -65,12 +64,12 @@ public:
 		return io_context;
 	}
 
-	gcc_pure
+	[[gnu::pure]]
 	auto GetSize() const noexcept {
 		return avio_size(io_context);
 	}
 
-	gcc_pure
+	[[gnu::pure]]
 	bool IsEOF() const noexcept {
 		return avio_feof(io_context) != 0;
 	}

src/lib/ffmpeg/Time.hxx

@@ -21,7 +21,6 @@
 #define MPD_FFMPEG_TIME_HXX
 
 #include "Chrono.hxx"
-#include "util/Compiler.h"
 
 extern "C" {
 #include <libavutil/avutil.h>
@@ -41,7 +40,7 @@ static constexpr AVRational AV_TIME_BASE_Q{1, AV_TIME_BASE};
 /**
  * Convert a FFmpeg time stamp to a floating point value (in seconds).
  */
-gcc_const
+[[gnu::const]]
 static inline FloatDuration
 FfmpegTimeToDouble(int64_t t, const AVRational time_base) noexcept
 {
@@ -64,7 +63,7 @@ RatioToAVRational()
 /**
  * Convert a FFmpeg time stamp to a #SongTime.
  */
-gcc_const
+[[gnu::const]]
 static inline SongTime
 FromFfmpegTime(int64_t t, const AVRational time_base) noexcept
 {
@@ -77,7 +76,7 @@ FromFfmpegTime(int64_t t, const AVRational time_base) noexcept
 /**
  * Convert a FFmpeg time stamp to a #SignedSongTime.
  */
-gcc_const
+[[gnu::const]]
 static inline SignedSongTime
 FromFfmpegTimeChecked(int64_t t, const AVRational time_base) noexcept
 {
@@ -89,7 +88,7 @@ FromFfmpegTimeChecked(int64_t t, const AVRational time_base) noexcept
 /**
  * Convert a #SongTime to a FFmpeg time stamp with the given base.
  */
-gcc_const
+[[gnu::const]]
 static inline int64_t
 ToFfmpegTime(SongTime t, const AVRational time_base) noexcept
 {
@@ -104,7 +103,7 @@ ToFfmpegTime(SongTime t, const AVRational time_base) noexcept
 constexpr int64_t
 FfmpegTimestampFallback(int64_t t, int64_t fallback)
 {
-	return gcc_likely(t != int64_t(AV_NOPTS_VALUE))
+	return t != int64_t(AV_NOPTS_VALUE)
 		? t
 		: fallback;
 }

src/lib/gcrypt/Hash.hxx

@@ -31,7 +31,6 @@
 #define GCRYPT_HASH_HXX
 
 #include "util/ConstBuffer.hxx"
-#include "util/Compiler.h"
 
 #include <gcrypt.h>
 
@@ -40,7 +39,7 @@
 namespace Gcrypt {
 
 template<int algo, size_t size>
-gcc_pure
+[[gnu::pure]]
 auto
 Hash(ConstBuffer<void> input) noexcept
 {

src/lib/gcrypt/MD5.hxx

@@ -31,7 +31,6 @@
 #define GCRYPT_MD5_HXX
 
 #include "util/StringBuffer.hxx"
-#include "util/Compiler.h"
 
 #include <array>
 #include <cstdint>
@@ -40,7 +39,7 @@ template<typename T> struct ConstBuffer;
 
 namespace Gcrypt {
 
-gcc_pure
+[[gnu::pure]]
 std::array<uint8_t, 16>
 MD5(ConstBuffer<void> input) noexcept;
 

src/lib/icu/Collate.cxx

@@ -76,7 +76,7 @@ IcuCollateFinish() noexcept
 
 #endif
 
-gcc_pure
+[[gnu::pure]]
 int
 IcuCollate(std::string_view a, std::string_view b) noexcept
 {

src/lib/icu/Collate.hxx

@@ -20,8 +20,6 @@
 #ifndef MPD_ICU_COLLATE_HXX
 #define MPD_ICU_COLLATE_HXX
 
-#include "util/Compiler.h"
-
 #include <string_view>
 
 /**
@@ -33,7 +31,7 @@ IcuCollateInit();
 void
 IcuCollateFinish() noexcept;
 
-gcc_pure
+[[gnu::pure]]
 int
 IcuCollate(std::string_view a, std::string_view b) noexcept;
 

src/lib/icu/Compare.hxx

@@ -20,7 +20,6 @@
 #ifndef MPD_ICU_COMPARE_HXX
 #define MPD_ICU_COMPARE_HXX
 
-#include "util/Compiler.h"
 #include "util/AllocatedString.hxx"
 
 #include <string_view>
@@ -63,15 +62,15 @@ public:
 	IcuCompare(IcuCompare &&) = default;
 	IcuCompare &operator=(IcuCompare &&) = default;
 
-	gcc_pure
+	[[gnu::pure]]
 	operator bool() const noexcept {
 		return needle != nullptr;
 	}
 
-	gcc_pure
+	[[gnu::pure]]
 	bool operator==(const char *haystack) const noexcept;
 
-	gcc_pure
+	[[gnu::pure]]
 	bool IsIn(const char *haystack) const noexcept;
 };
 

src/lib/icu/Converter.hxx

@@ -20,7 +20,6 @@
 #ifndef MPD_ICU_CONVERTER_HXX
 #define MPD_ICU_CONVERTER_HXX
 
-#include "util/Compiler.h"
 #include "config.h"
 
 #ifdef HAVE_ICU
@@ -84,7 +83,6 @@ public:
 	 *
 	 * Throws std::runtime_error on error.
 	 */
-	gcc_nonnull_all
 	AllocatedString ToUTF8(std::string_view s) const;
 
 	/**
@@ -92,7 +90,6 @@ public:
 	 *
 	 * Throws std::runtime_error on error.
 	 */
-	gcc_nonnull_all
 	AllocatedString FromUTF8(std::string_view s) const;
 };
 

src/lib/icu/Win32.hxx

@@ -20,8 +20,6 @@
 #ifndef MPD_ICU_WIN32_HXX
 #define MPD_ICU_WIN32_HXX
 
-#include "util/Compiler.h"
-
 #include <string_view>
 
 class AllocatedString;
@@ -30,14 +28,14 @@ template<typename T> class BasicAllocatedString;
 /**
  * Throws std::system_error on error.
  */
-gcc_pure gcc_nonnull_all
+[[gnu::pure]]
 AllocatedString
 WideCharToMultiByte(unsigned code_page, std::wstring_view src);
 
 /**
  * Throws std::system_error on error.
  */
-gcc_pure gcc_nonnull_all
+[[gnu::pure]]
 BasicAllocatedString<wchar_t>
 MultiByteToWideChar(unsigned code_page, std::string_view src);
 

src/lib/nfs/Base.hxx

@@ -20,8 +20,6 @@
 #ifndef MPD_NFS_BASE_HXX
 #define MPD_NFS_BASE_HXX
 
-#include "util/Compiler.h"
-
 /**
  * Set the "base" NFS server and export name.  This will be the
  * default export that will be mounted if a file within this export is
@@ -38,7 +36,7 @@ nfs_set_base(const char *server, const char *export_name) noexcept;
  * "path" after the export_name is returned; otherwise, nullptr is
  * returned.
  */
-gcc_pure
+[[gnu::pure]]
 const char *
 nfs_check_base(const char *server, const char *path) noexcept;
 

src/lib/nfs/Cancellable.hxx

@@ -20,8 +20,6 @@
 #ifndef MPD_NFS_CANCELLABLE_HXX
 #define MPD_NFS_CANCELLABLE_HXX
 
-#include "util/Compiler.h"
-
 #include <boost/intrusive/list.hpp>
 
 #include <algorithm>
@@ -89,35 +87,35 @@ private:
 		}
 	};
 
-	gcc_pure
+	[[gnu::pure]]
 	iterator Find(reference p) noexcept {
 		return std::find_if(list.begin(), list.end(), MatchPointer(p));
 	}
 
-	gcc_pure
+	[[gnu::pure]]
 	const_iterator Find(const_reference p) const noexcept {
 		return std::find_if(list.begin(), list.end(), MatchPointer(p));
 	}
 
-	gcc_pure
+	[[gnu::pure]]
 	iterator Find(CT &c) noexcept {
 		return list.iterator_to(c);
 	}
 
-	gcc_pure
+	[[gnu::pure]]
 	const_iterator Find(const CT &c) const noexcept {
 		return list.iterator_to(c);
 	}
 
 public:
 #ifndef NDEBUG
-	gcc_pure
+	[[gnu::pure]]
 	bool IsEmpty() const noexcept {
 		return std::all_of(list.begin(), list.end(), [](const auto &c) { return c.IsCancelled(); });
 	}
 #endif
 
-	gcc_pure
+	[[gnu::pure]]
 	bool Contains(const_reference p) const noexcept {
 		return Find(p) != list.end();
 	}

src/lib/nfs/Connection.hxx

@@ -24,7 +24,6 @@
 #include "event/SocketEvent.hxx"
 #include "event/CoarseTimerEvent.hxx"
 #include "event/DeferEvent.hxx"
-#include "util/Compiler.h"
 
 #include <string>
 #include <list>
@@ -139,7 +138,7 @@ class NfsConnection {
 	bool mount_finished;
 
 public:
-	gcc_nonnull_all
+	[[gnu::nonnull]]
 	NfsConnection(EventLoop &_loop,
 		      const char *_server, const char *_export_name) noexcept
 		:socket_event(_loop, BIND_THIS_METHOD(OnSocketReady)),
@@ -157,12 +156,12 @@ public:
 		return socket_event.GetEventLoop();
 	}
 
-	gcc_pure
+	[[gnu::pure]]
 	const char *GetServer() const noexcept {
 		return server.c_str();
 	}
 
-	gcc_pure
+	[[gnu::pure]]
 	const char *GetExportName() const noexcept {
 		return export_name.c_str();
 	}

src/lib/nfs/Glue.hxx

@@ -20,8 +20,6 @@
 #ifndef MPD_NFS_GLUE_HXX
 #define MPD_NFS_GLUE_HXX
 
-#include "util/Compiler.h"
-
 class EventLoop;
 class NfsConnection;
 
@@ -34,11 +32,11 @@ nfs_finish() noexcept;
 /**
  * Return the EventLoop that was passed to nfs_init().
  */
-gcc_const
+[[gnu::const]]
 EventLoop &
 nfs_get_event_loop() noexcept;
 
-gcc_pure
+[[gnu::pure]]
 NfsConnection &
 nfs_get_connection(const char *server, const char *export_name) noexcept;
 

src/lib/nfs/Manager.hxx

@@ -21,7 +21,6 @@
 #define MPD_NFS_MANAGER_HXX
 
 #include "Connection.hxx"
-#include "util/Compiler.h"
 #include "event/IdleEvent.hxx"
 
 #include <boost/intrusive/set.hpp>
@@ -56,15 +55,15 @@ class NfsManager final {
 	};
 
 	struct Compare {
-		gcc_pure
+		[[gnu::pure]]
 		bool operator()(const LookupKey a,
 				const ManagedConnection &b) const noexcept;
 
-		gcc_pure
+		[[gnu::pure]]
 		bool operator()(const ManagedConnection &a,
 				const LookupKey b) const noexcept;
 
-		gcc_pure
+		[[gnu::pure]]
 		bool operator()(const ManagedConnection &a,
 				const ManagedConnection &b) const noexcept;
 	};
@@ -102,7 +101,7 @@ public:
 		return idle_event.GetEventLoop();
 	}
 
-	gcc_pure
+	[[gnu::pure]]
 	NfsConnection &GetConnection(const char *server,
 				     const char *export_name) noexcept;
 

src/lib/pcre/RegexPointer.hxx

@@ -59,7 +59,7 @@ public:
 		return re != nullptr;
 	}
 
-	gcc_pure
+	[[gnu::pure]]
 	bool Match(StringView s) const noexcept {
 		/* we don't need the data written to ovector, but PCRE can
 		   omit internal allocations if we pass a buffer to

src/lib/upnp/ContentDirectoryService.hxx

@@ -21,7 +21,6 @@
 #define _UPNPDIR_HXX_INCLUDED_
 
 #include "Compat.hxx"
-#include "util/Compiler.h"
 
 #include <string>
 #include <forward_list>
@@ -112,7 +111,7 @@ public:
 	 */
 	std::forward_list<std::string> getSearchCapabilities(UpnpClient_Handle handle) const;
 
-	gcc_pure
+	[[gnu::pure]]
 	std::string GetURI() const noexcept {
 		return "upnp://" + m_deviceId + "/" + m_serviceType;
 	}

src/lib/xiph/FlacMetadataChain.hxx

@@ -20,8 +20,6 @@
 #ifndef MPD_FLAC_METADATA_CHAIN_HXX
 #define MPD_FLAC_METADATA_CHAIN_HXX
 
-#include "util/Compiler.h"
-
 #include <FLAC/metadata.h>
 
 class InputStream;
@@ -67,12 +65,12 @@ public:
 
 	bool ReadOgg(InputStream &is) noexcept;
 
-	gcc_pure
+	[[gnu::pure]]
 	FLAC__Metadata_ChainStatus GetStatus() const noexcept {
 		return ::FLAC__metadata_chain_status(chain);
 	}
 
-	gcc_pure
+	[[gnu::pure]]
 	const char *GetStatusString() const noexcept {
 		return FLAC__Metadata_ChainStatusString[GetStatus()];
 	}