jaotc: long compile time for synthesized class files

[tianxiaogu]

It takes a long time for jaotc to compile the attached generated class file (C0.class).
Actually, there are a couple of classes that can trigger the same behavior.
Since they may have the same cause, I attached just one of them here.

$ time ./openjdk/jdk/build/linux-x86_64-normal-server-release/jdk/bin/jaotc --output C0.so C0.class
Error: Failed compilation: C0.M7([Ljava/io/Serializable;[ZLjava/lang/Short;[ZFLjava/lang/Float;S[BC)J: java.lang.StackOverflowError

real	1m51.830s
user	7m12.364s
sys	0m2.364s
$ echo $?
0

[dougxc]

Thanks for the report. I've managed to come up with a unit test that reproduces the long compile time:

package org.graalvm.compiler.core.test;

import org.graalvm.compiler.core.common.GraalOptions;
import org.junit.Assert;
import org.junit.Test;

import jdk.vm.ci.meta.ResolvedJavaMethod;

public class TrivialInliningExplosionTest extends GraalCompilerTest {

    public static void M0() {
        M0();
        M0();
        M0();
    }

    public static void C0() {
        M0();
        M0();
        M0();
        M0();
        M0();
        M0();
        M0();
        M0();
        M0();
    }

    @Test
    public void test() {
        ResolvedJavaMethod methodC0 = getResolvedJavaMethod("C0");
        ResolvedJavaMethod methodM0 = getResolvedJavaMethod("M0");
        Assert.assertTrue(methodM0.getCodeSize() <= GraalOptions.TrivialInliningSize.getValue(getInitialOptions()));
        getCode(methodC0);
    }
}

It's still running after about 15 mins on my Mac.

[dougxc]

It seems the solution is to reduce the default value for -Dgraal.InlineDuringParsingMaxDepth from 10 to 3. I'll push a fix soon. This seems to fix the jaotc issue as well:

> time jaotc -J-Dgraal.InlineDuringParsingMaxDepth=3 C0.class
11.95user 0.51system 0:03.89elapsed 320%CPU (0avgtext+0avgdata 260508maxresident)k
0inputs+8outputs (0major+68507minor)pagefaults 0swaps

/cc @veresov

[dougxc]

The underlying Graal issue is fixed by 1b0ce5a. This probably won't show up in jaotc until JDK 11. Until then, adding -J-Dgraal.InlineDuringParsingMaxDepth=3 to the jaotc command line is the recommended workaround.