hg: valhalla/valhalla: 8222711: [lworld] Initial skeletal implementation of inline class instance construction via <init>

[Tobias Hartmann]

Hi Harold,

On 29.04.19 15:52, Harold Seigel wrote:
> Open Webrev: http://cr.openjdk.java.net/~hseigel/lworld_8222787/webrev/

The compiler changes look good to me.

> 2. Two hotspot JTReg compiler/valhalla tests fail with this change:
>     1. compiler/valhalla/valuetypes/TestBasicFunctionality.java
>     2. compiler/valhalla/valuetypes/TestLWorld.java

The tests fail because C2 does not inline some of the '<init>' methods although the constructor is
annotated with @ForceInline.

The test infrastructure iterates over all methods returned by Class::getDeclaredMethods and calls
WhiteBox::testSetForceInlineMethod for those methods annotated with @ForceInline:
http://hg.openjdk.java.net/valhalla/valhalla/file/eeb82eab9c31/test/hotspot/jtreg/compiler/valhalla/valuetypes/ValueTypeTest.java#l528

Now that worked with old 'makeValue' because it's a normal method and therefore returned by
getDeclaredMethods but it does not work with the new '<init>' constructor. Below is a little test
that shows the difference. Before, the test printed "public static MyValue1/val
MyValue1.$makeValue$(int)". Now it does not print anything.

If that is expected behavior, you can go ahead and fix it like this:

diff -r 51c89c6d10e6 test/hotspot/jtreg/compiler/valhalla/valuetypes/ValueTypeTest.java
--- a/test/hotspot/jtreg/compiler/valhalla/valuetypes/ValueTypeTest.java	Fri Apr 26 23:27:18 2019 +0530
+++ b/test/hotspot/jtreg/compiler/valhalla/valuetypes/ValueTypeTest.java	Tue Apr 30 17:35:09 2019 +0200
@@ -121,6 +121,7 @@
         "-XX:CompileCommand=compileonly,java.lang.invoke.*::*",
         "-XX:CompileCommand=compileonly,java.lang.Long::sum",
         "-XX:CompileCommand=compileonly,java.lang.Object::<init>",
+        "-XX:CompileCommand=inline,compiler.valhalla.valuetypes.MyValue*::<init>",
         "-XX:CompileCommand=compileonly,compiler.valhalla.valuetypes.*::*"};
     private static final String[] printFlags = {
         "-XX:+PrintCompilation", "-XX:+PrintIdeal", "-XX:+UnlockDiagnosticVMOptions",
"-XX:+PrintOptoAssembly"};

I've also noticed that code compiled with -XDnoStaticInitValueFactory throws a ClassFormatError when
executed. For example, below test fails with:

Exception in thread "main" java.lang.ClassFormatError: Method <init> in class MyValue1 (an inline
class) has illegal modifiers: 0x1
	at java.base/java.lang.ClassLoader.defineClass1(Native Method)
	at java.base/java.lang.ClassLoader.defineClass(ClassLoader.java:1016)
	at java.base/java.security.SecureClassLoader.defineClass(SecureClassLoader.java:151)
	at java.base/jdk.internal.loader.BuiltinClassLoader.defineClass(BuiltinClassLoader.java:823)

Best regards,
Tobias


import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Repeatable;
import java.lang.reflect.Method;

@Retention(RetentionPolicy.RUNTIME)
@interface ForceInline { }

value class MyValue1 {
    public final int x;

    @ForceInline
    public MyValue1(int x) {
        this.x = x;
    }
}

public class Test {

    public static void main(String[] args) throws Throwable {
        Method[] methods = MyValue1.class.getMethods();
        for (Method m : methods) {
            if (m.isAnnotationPresent(ForceInline.class)) {
                System.out.println(m);
            }
        }
    }
}