/*
 * Copyright (c) 2009, 2016, 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
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */
package com.oracle.graal.code;

import static java.util.Collections.emptyList;
import static java.util.Collections.unmodifiableList;
import static jdk.vm.ci.meta.MetaUtil.identityHashCodeString;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.List;
import java.util.Objects;

import jdk.vm.ci.code.DebugInfo;
import jdk.vm.ci.code.site.Call;
import jdk.vm.ci.code.site.ConstantReference;
import jdk.vm.ci.code.site.DataPatch;
import jdk.vm.ci.code.site.DataSectionReference;
import jdk.vm.ci.code.site.ExceptionHandler;
import jdk.vm.ci.code.site.Infopoint;
import jdk.vm.ci.code.site.InfopointReason;
import jdk.vm.ci.code.site.Mark;
import jdk.vm.ci.code.site.Reference;
import jdk.vm.ci.code.site.Site;
import jdk.vm.ci.meta.Assumptions.Assumption;
import jdk.vm.ci.meta.InvokeTarget;
import jdk.vm.ci.meta.ResolvedJavaMethod;

/**
 * Represents the output from compiling a method, including the compiled machine code, associated
 * data and references, relocation information, deoptimization information, etc.
 */
public class CompilationResult {

    /**
     * Provides extra information about instructions or data at specific positions in
     * {@link CompilationResult#getTargetCode()}. This is optional information that can be used to
     * enhance a disassembly of the code.
     */
    public abstract static class CodeAnnotation {

        public final int position;

        public CodeAnnotation(int position) {
            this.position = position;
        }

        @Override
        public final int hashCode() {
            throw new UnsupportedOperationException("hashCode");
        }

        @Override
        public String toString() {
            return identityHashCodeString(this);
        }

        @Override
        public abstract boolean equals(Object obj);
    }

    /**
     * A string comment about one or more instructions at a specific position in the code.
     */
    public static final class CodeComment extends CodeAnnotation {

        public final String value;

        public CodeComment(int position, String comment) {
            super(position);
            this.value = comment;
        }

        @Override
        public boolean equals(Object obj) {
            if (this == obj) {
                return true;
            }
            if (obj instanceof CodeComment) {
                CodeComment that = (CodeComment) obj;
                if (this.position == that.position && this.value.equals(that.value)) {
                    return true;
                }
            }
            return false;
        }

        @Override
        public String toString() {
            return getClass().getSimpleName() + "@" + position + ": " + value;
        }
    }

    /**
     * Describes a table of signed offsets embedded in the code. The offsets are relative to the
     * starting address of the table. This type of table maybe generated when translating a
     * multi-way branch based on a key value from a dense value set (e.g. the {@code tableswitch}
     * JVM instruction).
     *
     * The table is indexed by the contiguous range of integers from {@link #low} to {@link #high}
     * inclusive.
     */
    public static final class JumpTable extends CodeAnnotation {

        /**
         * The low value in the key range (inclusive).
         */
        public final int low;

        /**
         * The high value in the key range (inclusive).
         */
        public final int high;

        /**
         * The size (in bytes) of each table entry.
         */
        public final int entrySize;

        public JumpTable(int position, int low, int high, int entrySize) {
            super(position);
            this.low = low;
            this.high = high;
            this.entrySize = entrySize;
        }

        @Override
        public boolean equals(Object obj) {
            if (this == obj) {
                return true;
            }
            if (obj instanceof JumpTable) {
                JumpTable that = (JumpTable) obj;
                if (this.position == that.position && this.entrySize == that.entrySize && this.low == that.low && this.high == that.high) {
                    return true;
                }
            }
            return false;
        }

        @Override
        public String toString() {
            return getClass().getSimpleName() + "@" + position + ": [" + low + " .. " + high + "]";
        }
    }

    private boolean closed;

    private int entryBCI = -1;

    private final DataSection dataSection = new DataSection();

    private final List<Infopoint> infopoints = new ArrayList<>();
    private final List<DataPatch> dataPatches = new ArrayList<>();
    private final List<ExceptionHandler> exceptionHandlers = new ArrayList<>();
    private final List<Mark> marks = new ArrayList<>();

    private int totalFrameSize = -1;
    private int maxInterpreterFrameSize = -1;
    private int customStackAreaOffset = -1;

    private final String name;

    /**
     * The buffer containing the emitted machine code.
     */
    private byte[] targetCode;

    /**
     * The leading number of bytes in {@link #targetCode} containing the emitted machine code.
     */
    private int targetCodeSize;

    private ArrayList<CodeAnnotation> annotations;

    private Assumption[] assumptions;

    /**
     * The list of the methods whose bytecodes were used as input to the compilation. If
     * {@code null}, then the compilation did not record method dependencies. Otherwise, the first
     * element of this array is the root method of the compilation.
     */
    private ResolvedJavaMethod[] methods;

    private int bytecodeSize;

    private boolean hasUnsafeAccess;

    public CompilationResult() {
        this(null);
    }

    public CompilationResult(String name) {
        this.name = name;
    }

    @Override
    public int hashCode() {
        // CompilationResult instances should not be used as hash map keys
        throw new UnsupportedOperationException("hashCode");
    }

    @Override
    public String toString() {
        if (methods != null) {
            return getClass().getName() + "[" + methods[0].format("%H.%n(%p)%r") + "]";
        }
        return identityHashCodeString(this);
    }

    @Override
    public boolean equals(Object obj) {
        if (this == obj) {
            return true;
        }
        if (obj != null && obj.getClass() == getClass()) {
            CompilationResult that = (CompilationResult) obj;
            // @formatter:off
            if (this.entryBCI == that.entryBCI &&
                this.customStackAreaOffset == that.customStackAreaOffset &&
                this.totalFrameSize == that.totalFrameSize &&
                this.targetCodeSize == that.targetCodeSize &&
                Objects.equals(this.name, that.name) &&
                Objects.equals(this.annotations, that.annotations) &&
                Objects.equals(this.dataSection, that.dataSection) &&
                Objects.equals(this.exceptionHandlers, that.exceptionHandlers) &&
                Objects.equals(this.dataPatches, that.dataPatches) &&
                Objects.equals(this.infopoints, that.infopoints) &&
                Objects.equals(this.marks,  that.marks) &&
                Arrays.equals(this.assumptions, that.assumptions) &&
                Arrays.equals(targetCode, that.targetCode)) {
                return true;
            }
            // @formatter:on
        }
        return false;
    }

    /**
     * @return the entryBCI
     */
    public int getEntryBCI() {
        return entryBCI;
    }

    /**
     * @param entryBCI the entryBCI to set
     */
    public void setEntryBCI(int entryBCI) {
        checkOpen();
        this.entryBCI = entryBCI;
    }

    /**
     * Sets the assumptions made during compilation.
     */
    public void setAssumptions(Assumption[] assumptions) {
        checkOpen();
        this.assumptions = assumptions;
    }

    /**
     * Gets the assumptions made during compilation.
     *
     * The caller must not modify the contents of the returned array.
     */
    public Assumption[] getAssumptions() {
        return assumptions;
    }

    /**
     * Sets the methods whose bytecodes were used as input to the compilation.
     *
     * @param rootMethod the root method of the compilation
     * @param inlinedMethods the methods inlined during compilation
     */
    public void setMethods(ResolvedJavaMethod rootMethod, Collection<ResolvedJavaMethod> inlinedMethods) {
        checkOpen();
        assert rootMethod != null;
        assert inlinedMethods != null;
        if (inlinedMethods.contains(rootMethod)) {
            methods = inlinedMethods.toArray(new ResolvedJavaMethod[inlinedMethods.size()]);
            for (int i = 0; i < methods.length; i++) {
                if (methods[i].equals(rootMethod)) {
                    if (i != 0) {
                        ResolvedJavaMethod tmp = methods[0];
                        methods[0] = methods[i];
                        methods[i] = tmp;
                    }
                    break;
                }
            }
        } else {
            methods = new ResolvedJavaMethod[1 + inlinedMethods.size()];
            methods[0] = rootMethod;
            int i = 1;
            for (ResolvedJavaMethod m : inlinedMethods) {
                methods[i++] = m;
            }
        }
    }

    /**
     * Gets the methods whose bytecodes were used as input to the compilation.
     *
     * The caller must not modify the contents of the returned array.
     *
     * @return {@code null} if the compilation did not record method dependencies otherwise the
     *         methods whose bytecodes were used as input to the compilation with the first element
     *         being the root method of the compilation
     */
    public ResolvedJavaMethod[] getMethods() {
        return methods;
    }

    public void setBytecodeSize(int bytecodeSize) {
        checkOpen();
        this.bytecodeSize = bytecodeSize;
    }

    public int getBytecodeSize() {
        return bytecodeSize;
    }

    public DataSection getDataSection() {
        return dataSection;
    }

    /**
     * The total frame size of the method in bytes. This includes the return address pushed onto the
     * stack, if any.
     *
     * @return the frame size
     */
    public int getTotalFrameSize() {
        assert totalFrameSize != -1 : "frame size not yet initialized!";
        return totalFrameSize;
    }

    /**
     * Sets the total frame size in bytes. This includes the return address pushed onto the stack,
     * if any.
     *
     * @param size the size of the frame in bytes
     */
    public void setTotalFrameSize(int size) {
        checkOpen();
        totalFrameSize = size;
    }

    public int getMaxInterpreterFrameSize() {
        return maxInterpreterFrameSize;
    }

    public void setMaxInterpreterFrameSize(int maxInterpreterFrameSize) {
        checkOpen();
        this.maxInterpreterFrameSize = maxInterpreterFrameSize;
    }

    /**
     * Sets the machine that has been generated by the compiler.
     *
     * @param code the machine code generated
     * @param size the size of the machine code
     */
    public void setTargetCode(byte[] code, int size) {
        checkOpen();
        targetCode = code;
        targetCodeSize = size;
    }

    /**
     * Records a data patch in the code section. The data patch can refer to something in the
     * {@link DataSectionReference data section} or directly to an {@link ConstantReference inlined
     * constant}.
     *
     * @param codePos The position in the code that needs to be patched.
     * @param ref The reference that should be inserted in the code.
     */
    public void recordDataPatch(int codePos, Reference ref) {
        checkOpen();
        assert codePos >= 0 && ref != null;
        dataPatches.add(new DataPatch(codePos, ref));
    }

    /**
     * Records a call in the code array.
     *
     * @param codePos the position of the call in the code array
     * @param size the size of the call instruction
     * @param target the being called
     * @param debugInfo the debug info for the call
     * @param direct specifies if this is a {@linkplain Call#direct direct} call
     */
    public void recordCall(int codePos, int size, InvokeTarget target, DebugInfo debugInfo, boolean direct) {
        checkOpen();
        final Call call = new Call(target, codePos, size, direct, debugInfo);
        addInfopoint(call);
    }

    /**
     * Records an exception handler for this method.
     *
     * @param codePos the position in the code that is covered by the handler
     * @param handlerPos the position of the handler
     */
    public void recordExceptionHandler(int codePos, int handlerPos) {
        checkOpen();
        assert validateExceptionHandlerAdd(codePos, handlerPos) : String.format("Duplicate exception handler for pc 0x%x handlerPos 0x%x", codePos, handlerPos);
        exceptionHandlers.add(new ExceptionHandler(codePos, handlerPos));
    }

    /**
     * Validate if the exception handler for codePos already exists and handlerPos is different.
     *
     * @param codePos
     * @param handlerPos
     * @return true if the validation is successful
     */
    private boolean validateExceptionHandlerAdd(int codePos, int handlerPos) {
        ExceptionHandler exHandler = getExceptionHandlerForCodePos(codePos);
        return exHandler == null || exHandler.handlerPos == handlerPos;
    }

    /**
     * Returns the first ExceptionHandler which matches codePos.
     *
     * @param codePos position to search for
     * @return first matching ExceptionHandler
     */
    private ExceptionHandler getExceptionHandlerForCodePos(int codePos) {
        for (ExceptionHandler h : exceptionHandlers) {
            if (h.pcOffset == codePos) {
                return h;
            }
        }
        return null;
    }

    /**
     * Records an infopoint in the code array.
     *
     * @param codePos the position of the infopoint in the code array
     * @param debugInfo the debug info for the infopoint
     */
    public void recordInfopoint(int codePos, DebugInfo debugInfo, InfopointReason reason) {
        addInfopoint(new Infopoint(codePos, debugInfo, reason));
    }

    /**
     * Records a custom infopoint in the code section.
     *
     * Compiler implementations can use this method to record non-standard infopoints, which are not
     * handled by dedicated methods like {@link #recordCall}.
     *
     * @param infopoint the infopoint to record, usually a derived class from {@link Infopoint}
     */
    public void addInfopoint(Infopoint infopoint) {
        checkOpen();
        infopoints.add(infopoint);
    }

    /**
     * Records an instruction mark within this method.
     *
     * @param codePos the position in the code that is covered by the handler
     * @param markId the identifier for this mark
     */
    public Mark recordMark(int codePos, Object markId) {
        checkOpen();
        Mark mark = new Mark(codePos, markId);
        marks.add(mark);
        return mark;
    }

    /**
     * Offset in bytes for the custom stack area (relative to sp).
     *
     * @return the offset in bytes
     */
    public int getCustomStackAreaOffset() {
        return customStackAreaOffset;
    }

    /**
     * @see #getCustomStackAreaOffset()
     * @param offset
     */
    public void setCustomStackAreaOffset(int offset) {
        checkOpen();
        customStackAreaOffset = offset;
    }

    /**
     * @return the machine code generated for this method
     */
    public byte[] getTargetCode() {
        return targetCode;
    }

    /**
     * @return the size of the machine code generated for this method
     */
    public int getTargetCodeSize() {
        return targetCodeSize;
    }

    /**
     * @return the code annotations or {@code null} if there are none
     */
    public List<CodeAnnotation> getAnnotations() {
        if (annotations == null) {
            return Collections.emptyList();
        }
        return annotations;
    }

    public void addAnnotation(CodeAnnotation annotation) {
        checkOpen();
        assert annotation != null;
        if (annotations == null) {
            annotations = new ArrayList<>();
        }
        annotations.add(annotation);
    }

    /**
     * @return the list of infopoints, sorted by {@link Site#pcOffset}
     */
    public List<Infopoint> getInfopoints() {
        if (infopoints.isEmpty()) {
            return emptyList();
        }
        return unmodifiableList(infopoints);
    }

    /**
     * @return the list of data references
     */
    public List<DataPatch> getDataPatches() {
        if (dataPatches.isEmpty()) {
            return emptyList();
        }
        return unmodifiableList(dataPatches);
    }

    /**
     * @return the list of exception handlers
     */
    public List<ExceptionHandler> getExceptionHandlers() {
        if (exceptionHandlers.isEmpty()) {
            return emptyList();
        }
        return unmodifiableList(exceptionHandlers);
    }

    /**
     * @return the list of marks
     */
    public List<Mark> getMarks() {
        if (marks.isEmpty()) {
            return emptyList();
        }
        return unmodifiableList(marks);
    }

    public String getName() {
        return name;
    }

    public void setHasUnsafeAccess(boolean hasUnsafeAccess) {
        checkOpen();
        this.hasUnsafeAccess = hasUnsafeAccess;
    }

    public boolean hasUnsafeAccess() {
        return hasUnsafeAccess;
    }

    /**
     * Clears the information in this object pertaining to generating code. That is, the
     * {@linkplain #getMarks() marks}, {@linkplain #getInfopoints() infopoints},
     * {@linkplain #getExceptionHandlers() exception handlers}, {@linkplain #getDataPatches() data
     * patches} and {@linkplain #getAnnotations() annotations} recorded in this object are cleared.
     */
    public void resetForEmittingCode() {
        checkOpen();
        infopoints.clear();
        dataPatches.clear();
        exceptionHandlers.clear();
        marks.clear();
        dataSection.clear();
        if (annotations != null) {
            annotations.clear();
        }
    }

    private void checkOpen() {
        if (closed) {
            throw new IllegalStateException();
        }
    }

    /**
     * Closes this compilation result to future updates.
     */
    public void close() {
        if (closed) {
            throw new IllegalStateException("Cannot re-close compilation result " + this);
        }
        dataSection.close();
        closed = true;
    }
}