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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
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package org.openjdk.bench.java.lang.foreign;

import org.openjdk.jmh.annotations.Benchmark;
import org.openjdk.jmh.annotations.BenchmarkMode;
import org.openjdk.jmh.annotations.Fork;
import org.openjdk.jmh.annotations.Measurement;
import org.openjdk.jmh.annotations.Mode;
import org.openjdk.jmh.annotations.OutputTimeUnit;
import org.openjdk.jmh.annotations.State;
import org.openjdk.jmh.annotations.TearDown;
import org.openjdk.jmh.annotations.Warmup;

import java.lang.foreign.Arena;
import java.lang.foreign.FunctionDescriptor;
import java.lang.foreign.Linker;
import java.lang.foreign.MemoryLayout;
import java.lang.foreign.MemorySegment;
import java.lang.foreign.SegmentAllocator;
import java.lang.foreign.SymbolLookup;
import java.lang.foreign.ValueLayout;
import java.lang.invoke.MethodHandle;
import java.util.concurrent.TimeUnit;

import static org.openjdk.bench.java.lang.foreign.CLayouts.C_DOUBLE;

@BenchmarkMode(Mode.AverageTime)
@Warmup(iterations = 5, time = 500, timeUnit = TimeUnit.MILLISECONDS)
@Measurement(iterations = 5, time = 500, timeUnit = TimeUnit.MILLISECONDS)
@State(org.openjdk.jmh.annotations.Scope.Thread)
@OutputTimeUnit(TimeUnit.NANOSECONDS)
@Fork(value = 3, jvmArgs = { "--enable-native-access=ALL-UNNAMED", "-Djava.library.path=micro/native" })
public class CallOverheadByValue {

    public static final MemoryLayout POINT_LAYOUT = MemoryLayout.structLayout(
            C_DOUBLE, C_DOUBLE
    );
    private static final MethodHandle MH_UNIT_BY_VALUE;
    private static final MethodHandle MH_UNIT_BY_PTR;

    static {
        Linker abi = Linker.nativeLinker();
        System.loadLibrary("CallOverheadByValue");
        SymbolLookup loaderLibs = SymbolLookup.loaderLookup();
        MH_UNIT_BY_VALUE = abi.downcallHandle(
                loaderLibs.findOrThrow("unit"),
                FunctionDescriptor.of(POINT_LAYOUT)
        );
        MH_UNIT_BY_PTR = abi.downcallHandle(
                loaderLibs.findOrThrow("unit_ptr"),
                FunctionDescriptor.ofVoid(ValueLayout.ADDRESS)
        );
    }

    private static final Arena arena = Arena.ofConfined();
    private static final MemorySegment point = arena.allocate(POINT_LAYOUT);
    private static final SegmentAllocator BY_VALUE_ALLOCATOR = (SegmentAllocator) (_, _) -> point;

    @TearDown
    public void tearDown() {
        arena.close();
    }

    @Benchmark
    public void byValue() throws Throwable {
        // point = unit();
        MemorySegment unused = (MemorySegment) MH_UNIT_BY_VALUE.invokeExact(BY_VALUE_ALLOCATOR);
    }

    @Benchmark
    public void byPtr() throws Throwable {
        // unit_ptr(&point);
        MH_UNIT_BY_PTR.invokeExact(point);
    }

    @Fork(value = 3, jvmArgsAppend = "-Djmh.executor=VIRTUAL")
    public static class OfVirtual extends CallOverheadByValue {}

}