Import global functions and constants for enhanced performance

This is better for performance because these then don't need to be reevaluated every time they are called.

When encountering an unqualified function or constant reference, PHP will first try to locate a symbol in the current namespace by that name, and then fall back to the global namespace.
This short-circuits the check, which has substantial performance effects in some cases - in particular, ord(), chr() and strlen() show ~1500x faster calls when they are fully qualified.

However, this doesn't mean that PM is getting a massive amount faster. In real world terms, this translates to about 10-15% performance improvement.
But before anyone gets excited, you should know that the CodeOptimizer in the PreProcessor repo has been applying fully-qualified symbol optimizations to Jenkins builds for years, which is one of the reasons why Jenkins builds have better performance than home-built or source installations.
We're choosing to do this for the sake of future SafePHP integration and also to be able to get rid of the buggy CodeOptimizer, so that phar and source are more consistent.

src/pocketmine/command/Command.php

@@ -32,6 +32,8 @@ use pocketmine\permission\PermissionManager;
 use pocketmine\Server;
 use pocketmine\timings\TimingsHandler;
 use pocketmine\utils\TextFormat;
+use function explode;
+use function str_replace;
 
 abstract class Command{
 

src/pocketmine/command/CommandReader.php

@@ -26,6 +26,22 @@ namespace pocketmine\command;
 use pocketmine\snooze\SleeperNotifier;
 use pocketmine\Thread;
 use pocketmine\utils\Utils;
+use function extension_loaded;
+use function fclose;
+use function fgets;
+use function fopen;
+use function fstat;
+use function getopt;
+use function is_resource;
+use function microtime;
+use function preg_replace;
+use function readline;
+use function readline_add_history;
+use function stream_isatty;
+use function stream_select;
+use function trim;
+use function usleep;
+use const STDIN;
 
 class CommandReader extends Thread{
 

src/pocketmine/command/ConsoleCommandSender.php

@@ -31,6 +31,9 @@ use pocketmine\permission\PermissionAttachmentInfo;
 use pocketmine\plugin\Plugin;
 use pocketmine\Server;
 use pocketmine\utils\MainLogger;
+use function explode;
+use function trim;
+use const PHP_INT_MAX;
 
 class ConsoleCommandSender implements CommandSender{
 

src/pocketmine/command/FormattedCommandAlias.php

@@ -25,6 +25,11 @@ namespace pocketmine\command;
 
 use pocketmine\Server;
 use pocketmine\utils\TextFormat;
+use function count;
+use function ord;
+use function strlen;
+use function strpos;
+use function substr;
 
 class FormattedCommandAlias extends Command{
 	private $formatStrings = [];

src/pocketmine/command/RemoteConsoleCommandSender.php

@@ -24,6 +24,7 @@ declare(strict_types=1);
 namespace pocketmine\command;
 
 use pocketmine\lang\TextContainer;
+use function trim;
 
 class RemoteConsoleCommandSender extends ConsoleCommandSender{
 

src/pocketmine/command/SimpleCommandMap.php

@@ -66,6 +66,16 @@ use pocketmine\command\defaults\VersionCommand;
 use pocketmine\command\defaults\WhitelistCommand;
 use pocketmine\command\utils\InvalidCommandSyntaxException;
 use pocketmine\Server;
+use function array_map;
+use function array_shift;
+use function count;
+use function explode;
+use function implode;
+use function min;
+use function str_getcsv;
+use function strpos;
+use function strtolower;
+use function trim;
 
 class SimpleCommandMap implements CommandMap{
 
@@ -242,7 +252,7 @@ class SimpleCommandMap implements CommandMap{
 	}
 
 	public function dispatch(CommandSender $sender, string $commandLine) : bool{
-		$args = array_map("stripslashes", str_getcsv($commandLine, " "));
+		$args = array_map("\stripslashes", str_getcsv($commandLine, " "));
 		$sentCommandLabel = "";
 		$target = $this->matchCommand($sentCommandLabel, $args);
 

src/pocketmine/command/defaults/BanCommand.php

@@ -28,6 +28,9 @@ use pocketmine\command\CommandSender;
 use pocketmine\command\utils\InvalidCommandSyntaxException;
 use pocketmine\lang\TranslationContainer;
 use pocketmine\Player;
+use function array_shift;
+use function count;
+use function implode;
 
 class BanCommand extends VanillaCommand{
 

src/pocketmine/command/defaults/BanIpCommand.php

@@ -28,6 +28,10 @@ use pocketmine\command\CommandSender;
 use pocketmine\command\utils\InvalidCommandSyntaxException;
 use pocketmine\lang\TranslationContainer;
 use pocketmine\Player;
+use function array_shift;
+use function count;
+use function implode;
+use function preg_match;
 
 class BanIpCommand extends VanillaCommand{
 

src/pocketmine/command/defaults/BanListCommand.php

@@ -27,6 +27,10 @@ use pocketmine\command\CommandSender;
 use pocketmine\command\utils\InvalidCommandSyntaxException;
 use pocketmine\lang\TranslationContainer;
 use pocketmine\permission\BanEntry;
+use function array_map;
+use function count;
+use function implode;
+use function strtolower;
 
 class BanListCommand extends VanillaCommand{
 

src/pocketmine/command/defaults/DefaultGamemodeCommand.php

@@ -27,6 +27,7 @@ use pocketmine\command\CommandSender;
 use pocketmine\command\utils\InvalidCommandSyntaxException;
 use pocketmine\lang\TranslationContainer;
 use pocketmine\Server;
+use function count;
 
 class DefaultGamemodeCommand extends VanillaCommand{
 

src/pocketmine/command/defaults/DeopCommand.php

@@ -29,6 +29,8 @@ use pocketmine\command\utils\InvalidCommandSyntaxException;
 use pocketmine\lang\TranslationContainer;
 use pocketmine\Player;
 use pocketmine\utils\TextFormat;
+use function array_shift;
+use function count;
 
 class DeopCommand extends VanillaCommand{
 

src/pocketmine/command/defaults/DifficultyCommand.php

@@ -28,6 +28,7 @@ use pocketmine\command\CommandSender;
 use pocketmine\command\utils\InvalidCommandSyntaxException;
 use pocketmine\lang\TranslationContainer;
 use pocketmine\level\Level;
+use function count;
 
 class DifficultyCommand extends VanillaCommand{
 

src/pocketmine/command/defaults/DumpMemoryCommand.php

@@ -24,6 +24,7 @@ declare(strict_types=1);
 namespace pocketmine\command\defaults;
 
 use pocketmine\command\CommandSender;
+use function date;
 
 class DumpMemoryCommand extends VanillaCommand{
 

src/pocketmine/command/defaults/EffectCommand.php

@@ -29,6 +29,9 @@ use pocketmine\entity\Effect;
 use pocketmine\entity\EffectInstance;
 use pocketmine\lang\TranslationContainer;
 use pocketmine\utils\TextFormat;
+use function count;
+use function strtolower;
+use const INT32_MAX;
 
 class EffectCommand extends VanillaCommand{
 

src/pocketmine/command/defaults/EnchantCommand.php

@@ -29,6 +29,8 @@ use pocketmine\item\enchantment\Enchantment;
 use pocketmine\item\enchantment\EnchantmentInstance;
 use pocketmine\lang\TranslationContainer;
 use pocketmine\utils\TextFormat;
+use function count;
+use function is_numeric;
 
 class EnchantCommand extends VanillaCommand{
 

src/pocketmine/command/defaults/GamemodeCommand.php

@@ -30,6 +30,7 @@ use pocketmine\lang\TranslationContainer;
 use pocketmine\Player;
 use pocketmine\Server;
 use pocketmine\utils\TextFormat;
+use function count;
 
 class GamemodeCommand extends VanillaCommand{
 

src/pocketmine/command/defaults/GarbageCollectorCommand.php

@@ -25,6 +25,10 @@ namespace pocketmine\command\defaults;
 
 use pocketmine\command\CommandSender;
 use pocketmine\utils\TextFormat;
+use function count;
+use function memory_get_usage;
+use function number_format;
+use function round;
 
 class GarbageCollectorCommand extends VanillaCommand{
 

src/pocketmine/command/defaults/GiveCommand.php

@@ -31,6 +31,9 @@ use pocketmine\lang\TranslationContainer;
 use pocketmine\nbt\JsonNbtParser;
 use pocketmine\nbt\tag\CompoundTag;
 use pocketmine\utils\TextFormat;
+use function array_slice;
+use function count;
+use function implode;
 
 class GiveCommand extends VanillaCommand{
 

src/pocketmine/command/defaults/HelpCommand.php

@@ -27,6 +27,17 @@ use pocketmine\command\Command;
 use pocketmine\command\CommandSender;
 use pocketmine\lang\TranslationContainer;
 use pocketmine\utils\TextFormat;
+use function array_chunk;
+use function array_pop;
+use function count;
+use function explode;
+use function implode;
+use function is_numeric;
+use function ksort;
+use function min;
+use function strtolower;
+use const SORT_FLAG_CASE;
+use const SORT_NATURAL;
 
 class HelpCommand extends VanillaCommand{
 

src/pocketmine/command/defaults/KickCommand.php

@@ -29,6 +29,10 @@ use pocketmine\command\utils\InvalidCommandSyntaxException;
 use pocketmine\lang\TranslationContainer;
 use pocketmine\Player;
 use pocketmine\utils\TextFormat;
+use function array_shift;
+use function count;
+use function implode;
+use function trim;
 
 class KickCommand extends VanillaCommand{
 

src/pocketmine/command/defaults/KillCommand.php

@@ -30,6 +30,7 @@ use pocketmine\event\entity\EntityDamageEvent;
 use pocketmine\lang\TranslationContainer;
 use pocketmine\Player;
 use pocketmine\utils\TextFormat;
+use function count;
 
 class KillCommand extends VanillaCommand{
 

src/pocketmine/command/defaults/ListCommand.php

@@ -26,6 +26,10 @@ namespace pocketmine\command\defaults;
 use pocketmine\command\CommandSender;
 use pocketmine\lang\TranslationContainer;
 use pocketmine\Player;
+use function array_filter;
+use function array_map;
+use function count;
+use function implode;
 
 class ListCommand extends VanillaCommand{
 

src/pocketmine/command/defaults/MeCommand.php

@@ -28,6 +28,8 @@ use pocketmine\command\utils\InvalidCommandSyntaxException;
 use pocketmine\lang\TranslationContainer;
 use pocketmine\Player;
 use pocketmine\utils\TextFormat;
+use function count;
+use function implode;
 
 class MeCommand extends VanillaCommand{
 

src/pocketmine/command/defaults/OpCommand.php

@@ -29,6 +29,8 @@ use pocketmine\command\utils\InvalidCommandSyntaxException;
 use pocketmine\lang\TranslationContainer;
 use pocketmine\Player;
 use pocketmine\utils\TextFormat;
+use function array_shift;
+use function count;
 
 class OpCommand extends VanillaCommand{
 

src/pocketmine/command/defaults/PardonCommand.php

@@ -27,6 +27,7 @@ use pocketmine\command\Command;
 use pocketmine\command\CommandSender;
 use pocketmine\command\utils\InvalidCommandSyntaxException;
 use pocketmine\lang\TranslationContainer;
+use function count;
 
 class PardonCommand extends VanillaCommand{
 

src/pocketmine/command/defaults/PardonIpCommand.php

@@ -27,6 +27,8 @@ use pocketmine\command\Command;
 use pocketmine\command\CommandSender;
 use pocketmine\command\utils\InvalidCommandSyntaxException;
 use pocketmine\lang\TranslationContainer;
+use function count;
+use function preg_match;
 
 class PardonIpCommand extends VanillaCommand{
 

src/pocketmine/command/defaults/ParticleCommand.php

@@ -62,6 +62,13 @@ use pocketmine\math\Vector3;
 use pocketmine\Player;
 use pocketmine\utils\Random;
 use pocketmine\utils\TextFormat;
+use function count;
+use function explode;
+use function max;
+use function microtime;
+use function mt_rand;
+use function strpos;
+use function strtolower;
 
 class ParticleCommand extends VanillaCommand{
 

src/pocketmine/command/defaults/PluginsCommand.php

@@ -27,6 +27,9 @@ use pocketmine\command\CommandSender;
 use pocketmine\lang\TranslationContainer;
 use pocketmine\plugin\Plugin;
 use pocketmine\utils\TextFormat;
+use function array_map;
+use function count;
+use function implode;
 
 class PluginsCommand extends VanillaCommand{
 

src/pocketmine/command/defaults/SayCommand.php

@@ -29,6 +29,8 @@ use pocketmine\command\utils\InvalidCommandSyntaxException;
 use pocketmine\lang\TranslationContainer;
 use pocketmine\Player;
 use pocketmine\utils\TextFormat;
+use function count;
+use function implode;
 
 class SayCommand extends VanillaCommand{
 

src/pocketmine/command/defaults/SetWorldSpawnCommand.php

@@ -30,6 +30,8 @@ use pocketmine\lang\TranslationContainer;
 use pocketmine\math\Vector3;
 use pocketmine\Player;
 use pocketmine\utils\TextFormat;
+use function count;
+use function round;
 
 class SetWorldSpawnCommand extends VanillaCommand{
 

src/pocketmine/command/defaults/SpawnpointCommand.php

@@ -31,6 +31,8 @@ use pocketmine\level\Level;
 use pocketmine\level\Position;
 use pocketmine\Player;
 use pocketmine\utils\TextFormat;
+use function count;
+use function round;
 
 class SpawnpointCommand extends VanillaCommand{
 

src/pocketmine/command/defaults/StatusCommand.php

@@ -26,6 +26,11 @@ namespace pocketmine\command\defaults;
 use pocketmine\command\CommandSender;
 use pocketmine\utils\TextFormat;
 use pocketmine\utils\Utils;
+use function count;
+use function floor;
+use function microtime;
+use function number_format;
+use function round;
 
 class StatusCommand extends VanillaCommand{
 

src/pocketmine/command/defaults/TeleportCommand.php

@@ -30,6 +30,10 @@ use pocketmine\lang\TranslationContainer;
 use pocketmine\math\Vector3;
 use pocketmine\Player;
 use pocketmine\utils\TextFormat;
+use function array_filter;
+use function array_values;
+use function count;
+use function round;
 
 class TeleportCommand extends VanillaCommand{
 

src/pocketmine/command/defaults/TellCommand.php

@@ -28,6 +28,9 @@ use pocketmine\command\utils\InvalidCommandSyntaxException;
 use pocketmine\lang\TranslationContainer;
 use pocketmine\Player;
 use pocketmine\utils\TextFormat;
+use function array_shift;
+use function count;
+use function implode;
 
 class TellCommand extends VanillaCommand{
 

src/pocketmine/command/defaults/TimeCommand.php

@@ -30,6 +30,7 @@ use pocketmine\lang\TranslationContainer;
 use pocketmine\level\Level;
 use pocketmine\Player;
 use pocketmine\utils\TextFormat;
+use function count;
 
 class TimeCommand extends VanillaCommand{
 

src/pocketmine/command/defaults/TimingsCommand.php

@@ -31,6 +31,22 @@ use pocketmine\scheduler\BulkCurlTask;
 use pocketmine\Server;
 use pocketmine\timings\TimingsHandler;
 use pocketmine\utils\InternetException;
+use function count;
+use function fclose;
+use function file_exists;
+use function fopen;
+use function fseek;
+use function http_build_query;
+use function is_array;
+use function json_decode;
+use function mkdir;
+use function stream_get_contents;
+use function strtolower;
+use const CURLOPT_AUTOREFERER;
+use const CURLOPT_FOLLOWLOCATION;
+use const CURLOPT_HTTPHEADER;
+use const CURLOPT_POST;
+use const CURLOPT_POSTFIELDS;
 
 class TimingsCommand extends VanillaCommand{
 

src/pocketmine/command/defaults/TitleCommand.php

@@ -26,6 +26,9 @@ namespace pocketmine\command\defaults;
 use pocketmine\command\CommandSender;
 use pocketmine\command\utils\InvalidCommandSyntaxException;
 use pocketmine\lang\TranslationContainer;
+use function array_slice;
+use function count;
+use function implode;
 
 class TitleCommand extends VanillaCommand{
 

src/pocketmine/command/defaults/TransferServerCommand.php

@@ -28,6 +28,7 @@ namespace pocketmine\command\defaults;
 use pocketmine\command\CommandSender;
 use pocketmine\command\utils\InvalidCommandSyntaxException;
 use pocketmine\Player;
+use function count;
 
 class TransferServerCommand extends VanillaCommand{
 

src/pocketmine/command/defaults/VanillaCommand.php

@@ -28,6 +28,8 @@ use pocketmine\command\CommandSender;
 use pocketmine\command\utils\InvalidCommandSyntaxException;
 use pocketmine\lang\TranslationContainer;
 use pocketmine\utils\TextFormat;
+use function is_numeric;
+use function substr;
 
 abstract class VanillaCommand extends Command{
 	public const MAX_COORD = 30000000;

src/pocketmine/command/defaults/VersionCommand.php

@@ -28,6 +28,10 @@ use pocketmine\lang\TranslationContainer;
 use pocketmine\network\mcpe\protocol\ProtocolInfo;
 use pocketmine\plugin\Plugin;
 use pocketmine\utils\TextFormat;
+use function count;
+use function implode;
+use function stripos;
+use function strtolower;
 
 class VersionCommand extends VanillaCommand{
 

src/pocketmine/command/defaults/WhitelistCommand.php

@@ -28,6 +28,9 @@ use pocketmine\command\CommandSender;
 use pocketmine\command\utils\InvalidCommandSyntaxException;
 use pocketmine\lang\TranslationContainer;
 use pocketmine\utils\TextFormat;
+use function count;
+use function implode;
+use function strtolower;
 
 class WhitelistCommand extends VanillaCommand{