JIT: Unsafe putByte/putShort/putChar must narrow store to appropriate size

[BradleyWood]

Summary of problem

Methods such as Unsafe.putByte(...), Unsafe.putShort(...) may only store one/two bytes. By loading a 4-byte integer onto the stack and calling Unsafe.putShort(...), the attached application UnsafeSetMethodsTest.tar.gz demonstrates that the JIT incorrectly stores 4 bytes.

  public static Method setShort:"(Lsun/misc/Unsafe;Ljava/lang/Object;J)V"
    stack 5 locals 4
  {
        aload_0;
        aload_1;
        lload_2;
        ldc int -2122153084;
        invokevirtual   Method sun/misc/Unsafe.putShort:"(Ljava/lang/Object;JS)V";
        return;
  }

The test program shows that the interpreter stores the correct number of bytes, after JIT compilation, a full 4 bytes are stored.

$ java -Xjit:count=1,disableAsyncCompilation TestUnsafe
Values in o1
    i == -2122153084
    s == -31868
    c == 33668
    b == -124
Values in o2
    i == -2122153084
    s == -2122153084
    c == -2122153084
    b == -2122153084

[BradleyWood]

FYI, @hzongaro