/*

 * Copyright (c) 2017, 2019, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * 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

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

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package org.graalvm.compiler.core.gen;

import java.util.Collection;

import java.util.List;

import jdk.internal.vm.compiler.collections.EconomicSet;

import org.graalvm.compiler.code.CompilationResult;

import org.graalvm.compiler.core.LIRGenerationPhase;

import org.graalvm.compiler.core.LIRGenerationPhase.LIRGenerationContext;

import org.graalvm.compiler.core.common.GraalOptions;

import org.graalvm.compiler.core.common.alloc.ComputeBlockOrder;

import org.graalvm.compiler.core.common.alloc.RegisterAllocationConfig;

import org.graalvm.compiler.core.common.cfg.AbstractBlockBase;

import org.graalvm.compiler.core.target.Backend;

import org.graalvm.compiler.debug.CounterKey;

import org.graalvm.compiler.debug.DebugCloseable;

import org.graalvm.compiler.debug.DebugContext;

import org.graalvm.compiler.debug.GraalError;

import org.graalvm.compiler.debug.TimerKey;

import org.graalvm.compiler.lir.LIR;

import org.graalvm.compiler.lir.alloc.OutOfRegistersException;

import org.graalvm.compiler.lir.asm.CompilationResultBuilder;

import org.graalvm.compiler.lir.asm.CompilationResultBuilderFactory;

import org.graalvm.compiler.lir.framemap.FrameMap;

import org.graalvm.compiler.lir.gen.LIRGenerationResult;

import org.graalvm.compiler.lir.gen.LIRGeneratorTool;

import org.graalvm.compiler.lir.phases.AllocationPhase.AllocationContext;

import org.graalvm.compiler.lir.phases.LIRSuites;

import org.graalvm.compiler.lir.phases.PostAllocationOptimizationPhase.PostAllocationOptimizationContext;

import org.graalvm.compiler.lir.phases.PreAllocationOptimizationPhase.PreAllocationOptimizationContext;

import org.graalvm.compiler.nodes.StructuredGraph;

import org.graalvm.compiler.nodes.StructuredGraph.ScheduleResult;

import org.graalvm.compiler.nodes.cfg.Block;

import org.graalvm.compiler.nodes.spi.NodeLIRBuilderTool;

import jdk.vm.ci.code.RegisterConfig;

import jdk.vm.ci.code.TargetDescription;

import jdk.vm.ci.code.site.ConstantReference;

import jdk.vm.ci.code.site.DataPatch;

import jdk.vm.ci.meta.Assumptions;

import jdk.vm.ci.meta.JavaConstant;

import jdk.vm.ci.meta.JavaKind;

import jdk.vm.ci.meta.ResolvedJavaField;

import jdk.vm.ci.meta.ResolvedJavaMethod;

import jdk.vm.ci.meta.SpeculationLog;

import jdk.vm.ci.meta.VMConstant;

public class LIRCompilerBackend {

    private static final TimerKey EmitLIR = DebugContext.timer("EmitLIR").doc("Time spent generating LIR from HIR.");

    private static final TimerKey EmitCode = DebugContext.timer("EmitCode").doc("Time spent generating machine code from LIR.");

    private static final TimerKey BackEnd = DebugContext.timer("BackEnd").doc("Time spent in EmitLIR and EmitCode.");

    @SuppressWarnings("try")

    public static <T extends CompilationResult> void emitBackEnd(StructuredGraph graph, Object stub, ResolvedJavaMethod installedCodeOwner, Backend backend, T compilationResult,

                    CompilationResultBuilderFactory factory, RegisterConfig registerConfig, LIRSuites lirSuites) {

        DebugContext debug = graph.getDebug();

        try (DebugContext.Scope s = debug.scope("BackEnd", graph.getLastSchedule()); DebugCloseable a = BackEnd.start(debug)) {

            LIRGenerationResult lirGen = null;

            lirGen = emitLIR(backend, graph, stub, registerConfig, lirSuites);

            try (DebugContext.Scope s2 = debug.scope("CodeGen", lirGen, lirGen.getLIR())) {

                int bytecodeSize = graph.method() == null ? 0 : graph.getBytecodeSize();

                compilationResult.setHasUnsafeAccess(graph.hasUnsafeAccess());

                emitCode(backend,

                                graph.getAssumptions(),

                                graph.method(),

                                graph.getMethods(),

                                graph.getFields(),

                                graph.getSpeculationLog(),

                                bytecodeSize,

                                lirGen,

                                compilationResult,

                                installedCodeOwner,

                                factory);

            } catch (Throwable e) {

                throw debug.handle(e);

            }

        } catch (Throwable e) {

            throw debug.handle(e);

        } finally {

            graph.checkCancellation();

        }

    }

    @SuppressWarnings("try")

    public static LIRGenerationResult emitLIR(Backend backend, StructuredGraph graph, Object stub, RegisterConfig registerConfig, LIRSuites lirSuites) {

        String registerPressure = GraalOptions.RegisterPressure.getValue(graph.getOptions());

        String[] allocationRestrictedTo = registerPressure == null ? null : registerPressure.split(",");

        try {

            return emitLIR0(backend, graph, stub, registerConfig, lirSuites, allocationRestrictedTo);

        } catch (OutOfRegistersException e) {

            if (allocationRestrictedTo != null) {

                allocationRestrictedTo = null;

                return emitLIR0(backend, graph, stub, registerConfig, lirSuites, allocationRestrictedTo);

            }

            /* If the re-execution fails we convert the exception into a "hard" failure */

            throw new GraalError(e);

        } finally {

            graph.checkCancellation();

        }

    }

    @SuppressWarnings("try")

    private static LIRGenerationResult emitLIR0(Backend backend,

                    StructuredGraph graph,

                    Object stub,

                    RegisterConfig registerConfig,

                    LIRSuites lirSuites,

                    String[] allocationRestrictedTo) {

        DebugContext debug = graph.getDebug();

        try (DebugContext.Scope ds = debug.scope("EmitLIR"); DebugCloseable a = EmitLIR.start(debug)) {

            assert !graph.hasValueProxies();

            ScheduleResult schedule = graph.getLastSchedule();

            Block[] blocks = schedule.getCFG().getBlocks();

            Block startBlock = schedule.getCFG().getStartBlock();

            assert startBlock != null;

            assert startBlock.getPredecessorCount() == 0;

            AbstractBlockBase<?>[] codeEmittingOrder = ComputeBlockOrder.computeCodeEmittingOrder(blocks.length, startBlock);

            AbstractBlockBase<?>[] linearScanOrder = ComputeBlockOrder.computeLinearScanOrder(blocks.length, startBlock);

            LIR lir = new LIR(schedule.getCFG(), linearScanOrder, codeEmittingOrder, graph.getOptions(), graph.getDebug());

            LIRGenerationProvider lirBackend = (LIRGenerationProvider) backend;

            RegisterAllocationConfig registerAllocationConfig = backend.newRegisterAllocationConfig(registerConfig, allocationRestrictedTo);

            LIRGenerationResult lirGenRes = lirBackend.newLIRGenerationResult(graph.compilationId(), lir, registerAllocationConfig, graph, stub);

            LIRGeneratorTool lirGen = lirBackend.newLIRGenerator(lirGenRes);

            NodeLIRBuilderTool nodeLirGen = lirBackend.newNodeLIRBuilder(graph, lirGen);

            // LIR generation

            LIRGenerationContext context = new LIRGenerationContext(lirGen, nodeLirGen, graph, schedule);

            new LIRGenerationPhase().apply(backend.getTarget(), lirGenRes, context);

            try (DebugContext.Scope s = debug.scope("LIRStages", nodeLirGen, lirGenRes, lir)) {

                // Dump LIR along with HIR (the LIR is looked up from context)

                debug.dump(DebugContext.BASIC_LEVEL, graph.getLastSchedule(), "After LIR generation");

                LIRGenerationResult result = emitLowLevel(backend.getTarget(), lirGenRes, lirGen, lirSuites, registerAllocationConfig);

                return result;

            } catch (Throwable e) {

                throw debug.handle(e);

            }

        } catch (Throwable e) {

            throw debug.handle(e);

        } finally {

            graph.checkCancellation();

        }

    }

    private static LIRGenerationResult emitLowLevel(TargetDescription target, LIRGenerationResult lirGenRes, LIRGeneratorTool lirGen, LIRSuites lirSuites,

                    RegisterAllocationConfig registerAllocationConfig) {

        DebugContext debug = lirGenRes.getLIR().getDebug();

        PreAllocationOptimizationContext preAllocOptContext = new PreAllocationOptimizationContext(lirGen);

        lirSuites.getPreAllocationOptimizationStage().apply(target, lirGenRes, preAllocOptContext);

        debug.dump(DebugContext.BASIC_LEVEL, lirGenRes.getLIR(), "After PreAllocationOptimizationStage");

        AllocationContext allocContext = new AllocationContext(lirGen.getSpillMoveFactory(), registerAllocationConfig);

        lirSuites.getAllocationStage().apply(target, lirGenRes, allocContext);

        debug.dump(DebugContext.BASIC_LEVEL, lirGenRes.getLIR(), "After AllocationStage");

        PostAllocationOptimizationContext postAllocOptContext = new PostAllocationOptimizationContext(lirGen);

        lirSuites.getPostAllocationOptimizationStage().apply(target, lirGenRes, postAllocOptContext);

        debug.dump(DebugContext.BASIC_LEVEL, lirGenRes.getLIR(), "After PostAllocationOptimizationStage");

        return lirGenRes;

    }

    @SuppressWarnings("try")

    public static void emitCode(Backend backend,

                    Assumptions assumptions,

                    ResolvedJavaMethod rootMethod,

                    Collection<ResolvedJavaMethod> inlinedMethods,

                    EconomicSet<ResolvedJavaField> accessedFields,

                    SpeculationLog speculationLog,

                    int bytecodeSize,

                    LIRGenerationResult lirGenRes,

                    CompilationResult compilationResult,

                    ResolvedJavaMethod installedCodeOwner,

                    CompilationResultBuilderFactory factory) {

        DebugContext debug = lirGenRes.getLIR().getDebug();

        try (DebugCloseable a = EmitCode.start(debug)) {

            LIRGenerationProvider lirBackend = (LIRGenerationProvider) backend;

            FrameMap frameMap = lirGenRes.getFrameMap();

            CompilationResultBuilder crb = lirBackend.newCompilationResultBuilder(lirGenRes, frameMap, compilationResult, factory);

            lirBackend.emitCode(crb, lirGenRes.getLIR(), installedCodeOwner);

            if (assumptions != null && !assumptions.isEmpty()) {

                compilationResult.setAssumptions(assumptions.toArray());

            }

            if (rootMethod != null) {

                compilationResult.setMethods(rootMethod, inlinedMethods);

                compilationResult.setFields(accessedFields);

                compilationResult.setBytecodeSize(bytecodeSize);

            }

            if (speculationLog != null) {

                compilationResult.setSpeculationLog(speculationLog);

            }

            crb.finish();

            if (debug.isCountEnabled()) {

                List<DataPatch> ldp = compilationResult.getDataPatches();

                JavaKind[] kindValues = JavaKind.values();

                CounterKey[] dms = new CounterKey[kindValues.length];

                for (int i = 0; i < dms.length; i++) {

                    dms[i] = DebugContext.counter("DataPatches-%s", kindValues[i]);

                }

                for (DataPatch dp : ldp) {

                    JavaKind kind = JavaKind.Illegal;

                    if (dp.reference instanceof ConstantReference) {

                        VMConstant constant = ((ConstantReference) dp.reference).getConstant();

                        if (constant instanceof JavaConstant) {

                            kind = ((JavaConstant) constant).getJavaKind();

                        }

                    }

                    dms[kind.ordinal()].add(debug, 1);

                }

                DebugContext.counter("CompilationResults").increment(debug);

                DebugContext.counter("CodeBytesEmitted").add(debug, compilationResult.getTargetCodeSize());

                DebugContext.counter("InfopointsEmitted").add(debug, compilationResult.getInfopoints().size());

                DebugContext.counter("DataPatches").add(debug, ldp.size());

                DebugContext.counter("ExceptionHandlersEmitted").add(debug, compilationResult.getExceptionHandlers().size());

            }

            debug.dump(DebugContext.BASIC_LEVEL, compilationResult, "After code generation");

        }

    }

}