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package org.graalvm.compiler.core.test.tutorial;

import static org.graalvm.compiler.core.common.CompilationRequestIdentifier.asCompilationRequest;
import static org.graalvm.compiler.core.test.GraalCompilerTest.getInitialOptions;

import java.lang.reflect.Method;

import org.graalvm.compiler.api.test.Graal;
import org.graalvm.compiler.code.CompilationResult;
import org.graalvm.compiler.core.GraalCompiler;
import org.graalvm.compiler.core.common.CompilationIdentifier;
import org.graalvm.compiler.core.target.Backend;
import org.graalvm.compiler.debug.DebugHandlersFactory;
import org.graalvm.compiler.debug.DebugContext;
import org.graalvm.compiler.debug.DebugDumpScope;
import org.graalvm.compiler.lir.asm.CompilationResultBuilderFactory;
import org.graalvm.compiler.lir.phases.LIRSuites;
import org.graalvm.compiler.nodes.StructuredGraph;
import org.graalvm.compiler.nodes.StructuredGraph.AllowAssumptions;
import org.graalvm.compiler.options.OptionValues;
import org.graalvm.compiler.phases.OptimisticOptimizations;
import org.graalvm.compiler.phases.PhaseSuite;
import org.graalvm.compiler.phases.tiers.HighTierContext;
import org.graalvm.compiler.phases.tiers.Suites;
import org.graalvm.compiler.phases.util.Providers;
import org.graalvm.compiler.runtime.RuntimeProvider;

import jdk.vm.ci.code.CodeCacheProvider;
import jdk.vm.ci.code.InstalledCode;
import jdk.vm.ci.meta.MetaAccessProvider;
import jdk.vm.ci.meta.ProfilingInfo;
import jdk.vm.ci.meta.ResolvedJavaMethod;

Sample code that shows how to invoke Graal from an application.
/**
 * Sample code that shows how to invoke Graal from an application.
 */
public class InvokeGraal {

    protected final Backend backend;
    protected final Providers providers;
    protected final MetaAccessProvider metaAccess;
    protected final CodeCacheProvider codeCache;

    public InvokeGraal() {
        /* Ask the hosting Java VM for the entry point object to the Graal API. */
        RuntimeProvider runtimeProvider = Graal.getRequiredCapability(RuntimeProvider.class);

        /*
         * The default backend (architecture, VM configuration) that the hosting VM is running on.
         */
        backend = runtimeProvider.getHostBackend();
        /* Access to all of the Graal API providers, as implemented by the hosting VM. */
        providers = backend.getProviders();
        /* Some frequently used providers and configuration objects. */
        metaAccess = providers.getMetaAccess();
        codeCache = providers.getCodeCache();
    }

    
The simplest way to compile a method, using the default behavior for everything.
/**
     * The simplest way to compile a method, using the default behavior for everything.
     */
    @SuppressWarnings("try")
    protected InstalledCode compileAndInstallMethod(ResolvedJavaMethod method) {
        /* Create a unique compilation identifier, visible in IGV. */
        CompilationIdentifier compilationId = backend.getCompilationIdentifier(method);
        OptionValues options = getInitialOptions();
        DebugContext debug = DebugContext.create(options, DebugHandlersFactory.LOADER);
        try (DebugContext.Scope s = debug.scope("compileAndInstallMethod", new DebugDumpScope(String.valueOf(compilationId), true))) {

            /*
             * The graph that is compiled. We leave it empty (no nodes added yet). This means that
             * it will be filled according to the graphBuilderSuite defined below. We also specify
             * that we want the compilation to make optimistic assumptions about runtime state such
             * as the loaded class hierarchy.
             */
            StructuredGraph graph = new StructuredGraph.Builder(options, debug, AllowAssumptions.YES).method(method).compilationId(compilationId).build();

            /*
             * The phases used to build the graph. Usually this is just the GraphBuilderPhase. If
             * the graph already contains nodes, it is ignored.
             */
            PhaseSuite<HighTierContext> graphBuilderSuite = backend.getSuites().getDefaultGraphBuilderSuite();

            /*
             * The optimization phases that are applied to the graph. This is the main configuration
             * point for Graal. Add or remove phases to customize your compilation.
             */
            Suites suites = backend.getSuites().getDefaultSuites(options);

            /*
             * The low-level phases that are applied to the low-level representation.
             */
            LIRSuites lirSuites = backend.getSuites().getDefaultLIRSuites(options);

            /*
             * We want Graal to perform all speculative optimistic optimizations, using the
             * profiling information that comes with the method (collected by the interpreter) for
             * speculation.
             */
            OptimisticOptimizations optimisticOpts = OptimisticOptimizations.ALL;
            ProfilingInfo profilingInfo = graph.getProfilingInfo(method);

            /* The default class and configuration for compilation results. */
            CompilationResult compilationResult = new CompilationResult(graph.compilationId());
            CompilationResultBuilderFactory factory = CompilationResultBuilderFactory.Default;

            /* Invoke the whole Graal compilation pipeline. */
            GraalCompiler.compileGraph(graph, method, providers, backend, graphBuilderSuite, optimisticOpts, profilingInfo, suites, lirSuites, compilationResult, factory, true);

            /*
             * Install the compilation result into the VM, i.e., copy the byte[] array that contains
             * the machine code into an actual executable memory location.
             */
            return backend.addInstalledCode(debug, method, asCompilationRequest(compilationId), compilationResult);
        } catch (Throwable ex) {
            throw debug.handle(ex);
        }
    }

    
Look up a method using Java reflection and convert it to the Graal API method object.
/**
     * Look up a method using Java reflection and convert it to the Graal API method object.
     */
    protected ResolvedJavaMethod findMethod(Class<?> declaringClass, String name) {
        Method reflectionMethod = null;
        for (Method m : declaringClass.getDeclaredMethods()) {
            if (m.getName().equals(name)) {
                assert reflectionMethod == null : "More than one method with name " + name + " in class " + declaringClass.getName();
                reflectionMethod = m;
            }
        }
        assert reflectionMethod != null : "No method with name " + name + " in class " + declaringClass.getName();
        return metaAccess.lookupJavaMethod(reflectionMethod);
    }
}