Merge pull request #473 in G/truffleruby from opt-pointer to master

* commit '6eb2b31f33e0925e8d0765b5511862e6e7dc3066':
  Add missing primitives for reading/writing float and double
  Optimize pointer accesses
  Invoke the primitive directly instead of adding one indirection
  Build the Array with the right size instead of using #<<
  Simplify condition

Author: nirvdrum

src/main/java/org/truffleruby/core/CoreLibrary.java

@@ -1423,6 +1423,7 @@ public DynamicObject getWarningModule() {
             "/core/true.rb",
             "/core/type.rb",
             "/core/truffle/ffi/pointer.rb",
+            "/core/truffle/ffi/pointer_access.rb",
             "/core/truffle/internal.rb",
             "/core/kernel.rb",
             "/core/truffle/boot.rb",

src/main/java/org/truffleruby/extra/ffi/Pointer.java

@@ -80,6 +80,16 @@ public void writeLong(long offset, long value) {
         UNSAFE.putLong(address + offset, value);
     }
 
+    public void writeFloat(long offset, float value) {
+        assert address + offset != 0;
+        UNSAFE.putFloat(address + offset, value);
+    }
+
+    public void writeDouble(long offset, double value) {
+        assert address + offset != 0;
+        UNSAFE.putDouble(address + offset, value);
+    }
+
     public void writePointer(long offset, Pointer value) {
         writeLong(offset, value.getAddress());
     }
@@ -147,6 +157,11 @@ public long readLong(long offset) {
         return UNSAFE.getLong(address + offset);
     }
 
+    public float readFloat(long offset) {
+        assert address + offset != 0;
+        return UNSAFE.getFloat(address + offset);
+    }
+
     public double readDouble(long offset) {
         assert address + offset != 0;
         return UNSAFE.getDouble(address + offset);