papermc/Spigot-Server-Patches/0084-Speedup-BlockPos-by-fixing-inlining.patch

From 2834f7d0e06dcee31ff8b6a2ba13be95a913adb2 Mon Sep 17 00:00:00 2001
From: Techcable <Techcable@outlook.com>
Date: Fri, 29 Jan 2016 03:24:21 -0600
Subject: [PATCH] Speedup BlockPos by fixing inlining

Normally the JVM can inline virtual getters by having two sets of code, one is the 'optimized' code and the other is the 'deoptimized' code.
If a single type is used 99% of the time, then its worth it to inline, and to revert to 'deoptimized' the 1% of the time we encounter other types.
But if two types are encountered commonly, then the JVM can't inline them both, and the call overhead remains.

This scenario also occurs with BlockPos and MutableBlockPos.
The variables in BlockPos are final, so MutableBlockPos can't modify them.
MutableBlockPos fixes this by adding custom mutable variables, and overriding the getters to access them.

This approach with utility methods that operate on MutableBlockPos and BlockPos.
Specific examples are BlockPosition.up(), and World.isValidLocation().
It makes these simple methods much slower than they need to be.

This should result in an across the board speedup in anything that accesses blocks or does logic with positions.

This is based upon conclusions drawn from inspecting the assenmbly generated bythe JIT compiler on my mircorbenchmarks.
They had 'callq' (invoke) instead of 'mov' (get from memory) instructions.

diff --git a/src/main/java/net/minecraft/server/BaseBlockPosition.java b/src/main/java/net/minecraft/server/BaseBlockPosition.java
index 0b2277c..a685e08 100644
--- a/src/main/java/net/minecraft/server/BaseBlockPosition.java
+++ b/src/main/java/net/minecraft/server/BaseBlockPosition.java
@@ -5,9 +5,11 @@ import com.google.common.base.Objects;
 public class BaseBlockPosition implements Comparable<BaseBlockPosition> {
 
     public static final BaseBlockPosition ZERO = new BaseBlockPosition(0, 0, 0);
-    private final int a;
-    private final int c;
-    private final int d;
+    // PaperSpigot start - Make mutable and protected for MutableBlockPos
+    protected int a;
+    protected int c;
+    protected int d;
+    // PaperSpigot end
 
     public BaseBlockPosition(int i, int j, int k) {
         this.a = i;
@@ -39,17 +41,19 @@ public class BaseBlockPosition implements Comparable<BaseBlockPosition> {
         return this.getY() == baseblockposition.getY() ? (this.getZ() == baseblockposition.getZ() ? this.getX() - baseblockposition.getX() : this.getZ() - baseblockposition.getZ()) : this.getY() - baseblockposition.getY();
     }
 
-    public int getX() {
+    // PaperSpigot start - Only allow one implementation of these methods (make final)
+    public final int getX() {
         return this.a;
     }
 
-    public int getY() {
+    public final int getY() {
         return this.c;
     }
 
-    public int getZ() {
+    public final int getZ() {
         return this.d;
     }
+    // PaperSpigot end
 
     public BaseBlockPosition d(BaseBlockPosition baseblockposition) {
         return new BaseBlockPosition(this.getY() * baseblockposition.getZ() - this.getZ() * baseblockposition.getY(), this.getZ() * baseblockposition.getX() - this.getX() * baseblockposition.getZ(), this.getX() * baseblockposition.getY() - this.getY() * baseblockposition.getX());
@@ -79,7 +83,8 @@ public class BaseBlockPosition implements Comparable<BaseBlockPosition> {
         return Objects.toStringHelper(this).add("x", this.getX()).add("y", this.getY()).add("z", this.getZ()).toString();
     }
 
-    public int compareTo(Object object) {
+    // Paperspigot - Signature change, Object -> BaseBlockPosition
+    public int compareTo(BaseBlockPosition object) {
         return this.g((BaseBlockPosition) object);
     }
 }
diff --git a/src/main/java/net/minecraft/server/BlockPosition.java b/src/main/java/net/minecraft/server/BlockPosition.java
index 2bd5499..8ea95f2 100644
--- a/src/main/java/net/minecraft/server/BlockPosition.java
+++ b/src/main/java/net/minecraft/server/BlockPosition.java
@@ -198,9 +198,11 @@ public class BlockPosition extends BaseBlockPosition {
                                 ++k;
                             }
 
-                            this.b.c = i;
-                            this.b.d = j;
-                            this.b.e = k;
+                            // PaperSpigot start
+                            this.b.setX(i);
+                            this.b.setY(j);
+                            this.b.setZ(k);
+                            // PaperSpigot stop
                             return this.b;
                         }
                     }
@@ -219,9 +221,25 @@ public class BlockPosition extends BaseBlockPosition {
 
     public static final class MutableBlockPosition extends BlockPosition {
 
+        // PaperSpigot start - remove our overriding variables
+        /*
         private int c;
         private int d;
         private int e;
+        */
+
+        public void setX(int x) {
+            ((BaseBlockPosition) this).a = x;
+        }
+
+        public void setY(int y) {
+            ((BaseBlockPosition) this).c = y;
+        }
+
+        public void setZ(int z) {
+            ((BaseBlockPosition) this).d = z;
+        }
+        // PaperSpigot end
 
         public MutableBlockPosition() {
             this(0, 0, 0);
@@ -229,11 +247,13 @@ public class BlockPosition extends BaseBlockPosition {
 
         public MutableBlockPosition(int i, int j, int k) {
             super(0, 0, 0);
-            this.c = i;
-            this.d = j;
-            this.e = k;
+            // PaperSpigot start - modify base x,y,z
+            this.setX(i);
+            this.setY(j);
+            this.setY(k);
         }
 
+        /*
         public int getX() {
             return this.c;
         }
@@ -245,11 +265,13 @@ public class BlockPosition extends BaseBlockPosition {
         public int getZ() {
             return this.e;
         }
+        */
 
         public BlockPosition.MutableBlockPosition c(int i, int j, int k) {
-            this.c = i;
-            this.d = j;
-            this.e = k;
+            setX(i);
+            setY(j);
+            setZ(k);
+            // PaperSpigot end
             return this;
         }
 
-- 
2.7.0