Paper/Spigot-Server-Patches/0251-Improve-BlockPosition-inline-and-hashCode-equals.patch

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Techcable <Techcable@outlook.com>
Date: Wed, 30 Nov 2016 20:56:58 -0600
Subject: [PATCH] Improve BlockPosition inline and hashCode/equals

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 microbenchmarks.
They had 'callq' (invoke) instead of 'mov' (get from memory) instructions.

Co-Authored-By: Aikar <aikar@aikar.co>
for:
Also cache the hashCode and long values to use it for speeding up hashmap usage

diff --git a/src/main/java/net/minecraft/server/BaseBlockPosition.java b/src/main/java/net/minecraft/server/BaseBlockPosition.java
index 71089442c189336fc0061852a661581784a64013..334a6ab0df1978c42fdf8ad454e96f60e70c76dc 100644
--- a/src/main/java/net/minecraft/server/BaseBlockPosition.java
+++ b/src/main/java/net/minecraft/server/BaseBlockPosition.java
@@ -7,32 +7,32 @@ import javax.annotation.concurrent.Immutable;
 public class BaseBlockPosition implements Comparable<BaseBlockPosition> {
 
     public static final BaseBlockPosition ZERO = new BaseBlockPosition(0, 0, 0);
-    @Deprecated
-    private final int a;
-    @Deprecated
-    private final int b;
-    @Deprecated
-    private final int c;
     // Paper start
-    public boolean isValidLocation() {
-        return a >= -30000000 && c >= -30000000 && a < 30000000 && c < 30000000 && b >= 0 && b < 256;
+    protected int x; // If these ever become non final, review this entire patch, look for places need to rehash on write
+    protected int y;
+    protected int z;
+    private int hashCodeCached = 0;
+    private long cachedLong = Long.MAX_VALUE;
+
+    public final boolean isValidLocation() {
+        return x >= -30000000 && z >= -30000000 && x < 30000000 && z < 30000000 && y >= 0 && y < 256;
     }
-    public boolean isInvalidYLocation() {
-        return b < 0 || b >= 256;
+    public final boolean isInvalidYLocation() {
+        return y < 0 || y >= 256;
     }
     // Paper end
 
     public BaseBlockPosition(int i, int j, int k) {
-        this.a = i;
-        this.b = j;
-        this.c = k;
+        this.x = i;
+        this.y = j;
+        this.z = k;
     }
 
     public BaseBlockPosition(double d0, double d1, double d2) {
         this(MathHelper.floor(d0), MathHelper.floor(d1), MathHelper.floor(d2));
     }
 
-    public boolean equals(Object object) {
+    public final boolean equals(Object object) { // Paper
         if (this == object) {
             return true;
         } else if (!(object instanceof BaseBlockPosition)) {
@@ -40,29 +40,49 @@ public class BaseBlockPosition implements Comparable<BaseBlockPosition> {
         } else {
             BaseBlockPosition baseblockposition = (BaseBlockPosition) object;
 
-            return this.getX() != baseblockposition.getX() ? false : (this.getY() != baseblockposition.getY() ? false : this.getZ() == baseblockposition.getZ());
+            return this.asLong() == baseblockposition.asLong(); // Paper
         }
     }
 
-    public int hashCode() {
-        return (this.getY() + this.getZ() * 31) * 31 + this.getX();
+    public final int hashCode() {
+        // Paper start
+        if (this.cachedLong == Long.MAX_VALUE) {
+            rebuildCache();
+        }
+        return this.hashCodeCached;
+    }
+    private void rebuildCache() {
+        this.cachedLong = BlockPosition.asLong(getX(), getY(), getZ());
+        this.hashCodeCached = (this.getY() + this.getZ() * 1031) * 1031 + this.getX();
+    }
+    public final long asLong() {
+        if (this.cachedLong == Long.MAX_VALUE) {
+            rebuildCache();
+        }
+        return this.cachedLong;
+    }
+    public final void rehash() {
+        this.cachedLong = Long.MAX_VALUE;
+        // Paper end
     }
 
     public int compareTo(BaseBlockPosition 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() {
-        return this.a;
+    // Paper start
+    public final int getX() {
+        return this.x;
     }
 
-    public int getY() {
-        return this.b;
+    public final int getY() {
+        return this.y;
     }
 
-    public int getZ() {
-        return this.c;
+    public final int getZ() {
+        return this.z;
     }
+    // Paper end
 
     public BaseBlockPosition down() {
         return this.down(1);
@@ -75,13 +95,14 @@ public class BaseBlockPosition implements Comparable<BaseBlockPosition> {
     public BaseBlockPosition shift(EnumDirection enumdirection, int i) {
         return i == 0 ? this : new BaseBlockPosition(this.getX() + enumdirection.getAdjacentX() * i, this.getY() + enumdirection.getAdjacentY() * i, this.getZ() + enumdirection.getAdjacentZ() * i);
     }
+    // Paper 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());
     }
 
     public boolean a(BaseBlockPosition baseblockposition, double d0) {
-        return this.distanceSquared((double) baseblockposition.getX(), (double) baseblockposition.getY(), (double) baseblockposition.getZ(), false) < d0 * d0;
+        return this.distanceSquared((double) baseblockposition.x, (double) baseblockposition.y, (double) baseblockposition.z, false) < d0 * d0; // Paper
     }
 
     public boolean a(IPosition iposition, double d0) {
@@ -106,9 +127,9 @@ public class BaseBlockPosition implements Comparable<BaseBlockPosition> {
     }
 
     public int n(BaseBlockPosition baseblockposition) {
-        float f = (float) Math.abs(baseblockposition.getX() - this.getX());
-        float f1 = (float) Math.abs(baseblockposition.getY() - this.getY());
-        float f2 = (float) Math.abs(baseblockposition.getZ() - this.getZ());
+        float f = (float) Math.abs(baseblockposition.getX() - this.x); // Paper
+        float f1 = (float) Math.abs(baseblockposition.getY() - this.y); // Paper
+        float f2 = (float) Math.abs(baseblockposition.getZ() - this.z); // Paper
 
         return (int) (f + f1 + f2);
     }
diff --git a/src/main/java/net/minecraft/server/BlockPosition.java b/src/main/java/net/minecraft/server/BlockPosition.java
index f8ac39e1b019b0918996f745d99f6ed09db0fd11..0ce39e34c1d60ec0fc9d4a0e1b802d8c96177b4b 100644
--- a/src/main/java/net/minecraft/server/BlockPosition.java
+++ b/src/main/java/net/minecraft/server/BlockPosition.java
@@ -99,6 +99,7 @@ public class BlockPosition extends BaseBlockPosition implements MinecraftSeriali
         return new BlockPosition(b(i), c(i), d(i));
     }
 
+    public static long asLong(int x, int y, int z) { return a(x, y, z); } // Paper - OBFHELPER
     public static long a(int i, int j, int k) {
         long l = 0L;
 
@@ -112,7 +113,7 @@ public class BlockPosition extends BaseBlockPosition implements MinecraftSeriali
         return i & -16L;
     }
 
-    public long asLong() {
+    public long asLong_unused() { // Paper - moved to parent
         return a(this.getX(), this.getY(), this.getZ());
     }
 
@@ -343,11 +344,13 @@ public class BlockPosition extends BaseBlockPosition implements MinecraftSeriali
     }
 
     public static class MutableBlockPosition extends BlockPosition {
-
+        // Paper start - comment out
+        /*
         protected int b;
         protected int c;
         protected int d;
-
+        */
+        // Paper end
         public MutableBlockPosition() {
             this(0, 0, 0);
         }
@@ -357,10 +360,13 @@ public class BlockPosition extends BaseBlockPosition implements MinecraftSeriali
         }
 
         public MutableBlockPosition(int i, int j, int k) {
-            super(0, 0, 0);
+            // Paper start
+            super(i, j, k);
+            /*
             this.b = i;
             this.c = j;
-            this.d = k;
+            this.d = k;*/
+            // Paper end
         }
 
         public MutableBlockPosition(double d0, double d1, double d2) {
@@ -391,6 +397,9 @@ public class BlockPosition extends BaseBlockPosition implements MinecraftSeriali
             return super.a(enumblockrotation).immutableCopy();
         }
 
+
+        /*
+        // Paper start - use parent getters
         @Override
         public int getX() {
             return this.b;
@@ -404,13 +413,17 @@ public class BlockPosition extends BaseBlockPosition implements MinecraftSeriali
         @Override
         public int getZ() {
             return this.d;
-        }
+        }*/
+        // Paper end
 
         public BlockPosition.MutableBlockPosition setValues(int i, int j, int k) { return d(i, j, k);} // Paper - OBFHELPER
         public BlockPosition.MutableBlockPosition d(int i, int j, int k) {
-            this.b = i;
-            this.c = j;
-            this.d = k;
+            // Paper start - use xyz
+            this.x = i;
+            this.y = j;
+            this.z = k;
+            rehash();
+            // Paper end
             return this;
         }
 
@@ -440,26 +453,29 @@ public class BlockPosition extends BaseBlockPosition implements MinecraftSeriali
         }
 
         public BlockPosition.MutableBlockPosition c(EnumDirection enumdirection, int i) {
-            return this.d(this.b + enumdirection.getAdjacentX() * i, this.c + enumdirection.getAdjacentY() * i, this.d + enumdirection.getAdjacentZ() * i);
+            return this.d(this.x + enumdirection.getAdjacentX() * i, this.y + enumdirection.getAdjacentY() * i, this.z + enumdirection.getAdjacentZ() * i);
         }
 
         public BlockPosition.MutableBlockPosition e(int i, int j, int k) {
-            return this.d(this.b + i, this.c + j, this.d + k);
+            return this.d(this.x + i, this.y + j, this.z + k);
         }
 
         public final void setX(final int x) { this.o(x); } // Paper - OBFHELPER
         public void o(int i) {
-            this.b = i;
+            this.x = i; // Paper change to x
+            rehash(); // Paper
         }
 
         public final void setY(final int y) { this.p(y); } // Paper - OBFHELPER
         public void p(int i) {
-            this.c = i;
+            this.y = i; // Paper change to y
+            rehash(); // Paper
         }
 
         public final void setZ(final int z) { this.q(z); } // Paper - OBFHELPER
         public void q(int i) {
-            this.d = i;
+            this.z = i; // Paper change to z
+            rehash(); // Paper
         }
 
         @Override