/*

 * Copyright (c) 2010, 2013, 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.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * 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 jdk.nashorn.internal.codegen;

import static jdk.internal.org.objectweb.asm.Opcodes.ATHROW;

import static jdk.internal.org.objectweb.asm.Opcodes.CHECKCAST;

import static jdk.internal.org.objectweb.asm.Opcodes.DUP2;

import static jdk.internal.org.objectweb.asm.Opcodes.GETFIELD;

import static jdk.internal.org.objectweb.asm.Opcodes.GETSTATIC;

import static jdk.internal.org.objectweb.asm.Opcodes.GOTO;

import static jdk.internal.org.objectweb.asm.Opcodes.H_INVOKESTATIC;

import static jdk.internal.org.objectweb.asm.Opcodes.H_INVOKEINTERFACE;

import static jdk.internal.org.objectweb.asm.Opcodes.IFEQ;

import static jdk.internal.org.objectweb.asm.Opcodes.IFGE;

import static jdk.internal.org.objectweb.asm.Opcodes.IFGT;

import static jdk.internal.org.objectweb.asm.Opcodes.IFLE;

import static jdk.internal.org.objectweb.asm.Opcodes.IFLT;

import static jdk.internal.org.objectweb.asm.Opcodes.IFNE;

import static jdk.internal.org.objectweb.asm.Opcodes.IFNONNULL;

import static jdk.internal.org.objectweb.asm.Opcodes.IFNULL;

import static jdk.internal.org.objectweb.asm.Opcodes.IF_ACMPEQ;

import static jdk.internal.org.objectweb.asm.Opcodes.IF_ACMPNE;

import static jdk.internal.org.objectweb.asm.Opcodes.IF_ICMPEQ;

import static jdk.internal.org.objectweb.asm.Opcodes.IF_ICMPGE;

import static jdk.internal.org.objectweb.asm.Opcodes.IF_ICMPGT;

import static jdk.internal.org.objectweb.asm.Opcodes.IF_ICMPLE;

import static jdk.internal.org.objectweb.asm.Opcodes.IF_ICMPLT;

import static jdk.internal.org.objectweb.asm.Opcodes.IF_ICMPNE;

import static jdk.internal.org.objectweb.asm.Opcodes.INSTANCEOF;

import static jdk.internal.org.objectweb.asm.Opcodes.INVOKEINTERFACE;

import static jdk.internal.org.objectweb.asm.Opcodes.INVOKESPECIAL;

import static jdk.internal.org.objectweb.asm.Opcodes.INVOKESTATIC;

import static jdk.internal.org.objectweb.asm.Opcodes.INVOKEVIRTUAL;

import static jdk.internal.org.objectweb.asm.Opcodes.NEW;

import static jdk.internal.org.objectweb.asm.Opcodes.PUTFIELD;

import static jdk.internal.org.objectweb.asm.Opcodes.PUTSTATIC;

import static jdk.internal.org.objectweb.asm.Opcodes.RETURN;

import static jdk.nashorn.internal.codegen.CompilerConstants.ARGUMENTS;

import static jdk.nashorn.internal.codegen.CompilerConstants.CONSTANTS;

import static jdk.nashorn.internal.codegen.CompilerConstants.SCOPE;

import static jdk.nashorn.internal.codegen.CompilerConstants.THIS;

import static jdk.nashorn.internal.codegen.CompilerConstants.THIS_DEBUGGER;

import static jdk.nashorn.internal.codegen.CompilerConstants.VARARGS;

import static jdk.nashorn.internal.codegen.CompilerConstants.className;

import static jdk.nashorn.internal.codegen.CompilerConstants.constructorNoLookup;

import static jdk.nashorn.internal.codegen.CompilerConstants.methodDescriptor;

import static jdk.nashorn.internal.codegen.CompilerConstants.staticField;

import static jdk.nashorn.internal.codegen.CompilerConstants.virtualCallNoLookup;

import static jdk.nashorn.internal.codegen.ObjectClassGenerator.PRIMITIVE_FIELD_TYPE;

import static jdk.nashorn.internal.runtime.linker.NameCodec.EMPTY_NAME;

import static jdk.nashorn.internal.runtime.linker.NashornCallSiteDescriptor.CALLSITE_OPTIMISTIC;

import static jdk.nashorn.internal.runtime.linker.NashornCallSiteDescriptor.CALLSITE_PROGRAM_POINT_SHIFT;

import java.io.PrintStream;

import java.lang.reflect.Array;

import java.util.Collection;

import java.util.EnumSet;

import java.util.IdentityHashMap;

import java.util.List;

import java.util.Map;

import jdk.internal.org.objectweb.asm.Handle;

import jdk.internal.org.objectweb.asm.MethodVisitor;

import jdk.nashorn.internal.codegen.ClassEmitter.Flag;

import jdk.nashorn.internal.codegen.CompilerConstants.Call;

import jdk.nashorn.internal.codegen.CompilerConstants.FieldAccess;

import jdk.nashorn.internal.codegen.types.ArrayType;

import jdk.nashorn.internal.codegen.types.BitwiseType;

import jdk.nashorn.internal.codegen.types.NumericType;

import jdk.nashorn.internal.codegen.types.Type;

import jdk.nashorn.internal.ir.FunctionNode;

import jdk.nashorn.internal.ir.IdentNode;

import jdk.nashorn.internal.ir.JoinPredecessor;

import jdk.nashorn.internal.ir.LiteralNode;

import jdk.nashorn.internal.ir.LocalVariableConversion;

import jdk.nashorn.internal.ir.Symbol;

import jdk.nashorn.internal.ir.TryNode;

import jdk.nashorn.internal.objects.NativeArray;

import jdk.nashorn.internal.runtime.ArgumentSetter;

import jdk.nashorn.internal.runtime.Context;

import jdk.nashorn.internal.runtime.Debug;

import jdk.nashorn.internal.runtime.JSType;

import jdk.nashorn.internal.runtime.RewriteException;

import jdk.nashorn.internal.runtime.Scope;

import jdk.nashorn.internal.runtime.ScriptObject;

import jdk.nashorn.internal.runtime.ScriptRuntime;

import jdk.nashorn.internal.runtime.UnwarrantedOptimismException;

import jdk.nashorn.internal.runtime.linker.Bootstrap;

import jdk.nashorn.internal.runtime.linker.NameCodec;

import jdk.nashorn.internal.runtime.linker.NashornCallSiteDescriptor;

import jdk.nashorn.internal.runtime.logging.DebugLogger;

import jdk.nashorn.internal.runtime.options.Options;

/**

 * This is the main function responsible for emitting method code

 * in a class. It maintains a type stack and keeps track of control

 * flow to make sure that the registered instructions don't violate

 * byte code verification.

 *

 * Running Nashorn with -ea will assert as soon as a type stack

 * becomes corrupt, for easier debugging

 *

 * Running Nashorn with -Dnashorn.codegen.debug=true will print

 * all generated bytecode and labels to stderr, for easier debugging,

 * including bytecode stack contents

 */

public class MethodEmitter {

    /** The ASM MethodVisitor we are plugged into */

    private final MethodVisitor method;

    /** Parent classEmitter representing the class of this method */

    private final ClassEmitter classEmitter;

    /** FunctionNode representing this method, or null if none exists */

    protected FunctionNode functionNode;

    /** Current type stack for current evaluation */

    private Label.Stack stack;

    private boolean preventUndefinedLoad;

    /**

     * Map of live local variable definitions.

     */

    private final Map<Symbol, LocalVariableDef> localVariableDefs = new IdentityHashMap<>();

    /** The context */

    private final Context context;

    /** Threshold in chars for when string constants should be split */

    static final int LARGE_STRING_THRESHOLD = 32 * 1024;

    /** Debug flag, should we dump all generated bytecode along with stacks? */

    private final DebugLogger log;

    private final boolean     debug;

    /** dump stack on a particular line, or -1 if disabled */

    private static final int DEBUG_TRACE_LINE;

    static {

        final String tl = Options.getStringProperty("nashorn.codegen.debug.trace", "-1");

        int line = -1;

        try {

            line = Integer.parseInt(tl);

        } catch (final NumberFormatException e) {

            //fallthru

        }

        DEBUG_TRACE_LINE = line;

    }

    /** Bootstrap for normal indy:s */

    private static final Handle LINKERBOOTSTRAP  = new Handle(H_INVOKESTATIC, Bootstrap.BOOTSTRAP.className(), Bootstrap.BOOTSTRAP.name(), Bootstrap.BOOTSTRAP.descriptor(), false);

    /** Bootstrap for array populators */

    private static final Handle POPULATE_ARRAY_BOOTSTRAP = new Handle(H_INVOKESTATIC, RewriteException.BOOTSTRAP.className(), RewriteException.BOOTSTRAP.name(), RewriteException.BOOTSTRAP.descriptor(), false);

    /**

     * Constructor - internal use from ClassEmitter only

     * @see ClassEmitter#method

     *

     * @param classEmitter the class emitter weaving the class this method is in

     * @param method       a method visitor

     */

    MethodEmitter(final ClassEmitter classEmitter, final MethodVisitor method) {

        this(classEmitter, method, null);

    }

    /**

     * Constructor - internal use from ClassEmitter only

     * @see ClassEmitter#method

     *

     * @param classEmitter the class emitter weaving the class this method is in

     * @param method       a method visitor

     * @param functionNode a function node representing this method

     */

    MethodEmitter(final ClassEmitter classEmitter, final MethodVisitor method, final FunctionNode functionNode) {

        this.context      = classEmitter.getContext();

        this.classEmitter = classEmitter;

        this.method       = method;

        this.functionNode = functionNode;

        this.stack        = null;

        this.log          = context.getLogger(CodeGenerator.class);

        this.debug        = log.isEnabled();

    }

    /**

     * Begin a method

     */

    public void begin() {

        classEmitter.beginMethod(this);

        newStack();

        method.visitCode();

    }

    /**

     * End a method

     */

    public void end() {

        method.visitMaxs(0, 0);

        method.visitEnd();

        classEmitter.endMethod(this);

    }

    boolean isReachable() {

        return stack != null;

    }

    private void doesNotContinueSequentially() {

        stack = null;

    }

    private void newStack() {

        stack = new Label.Stack();

    }

    @Override

    public String toString() {

        return "methodEmitter: " + (functionNode == null ? method : functionNode.getName()).toString() + ' ' + Debug.id(this);

    }

    /**

     * Push a type to the existing stack

     * @param type the type

     */

    void pushType(final Type type) {

        if (type != null) {

            stack.push(type);

        }

    }

    /**

     * Pop a type from the existing stack

     *

     * @param expected expected type - will assert if wrong

     *

     * @return the type that was retrieved

     */

    private Type popType(final Type expected) {

        final Type type = popType();

        assert type.isEquivalentTo(expected) : type + " is not compatible with " + expected;

        return type;

    }

    /**

     * Pop a type from the existing stack, no matter what it is.

     *

     * @return the type

     */

    private Type popType() {

        return stack.pop();

    }

    /**

     * Pop a type from the existing stack, ensuring that it is numeric. Boolean type is popped as int type.

     *

     * @return the type

     */

    private NumericType popNumeric() {

        final Type type = popType();

        if(type.isBoolean()) {

            // Booleans are treated as int for purposes of arithmetic operations

            return Type.INT;

        }

        assert type.isNumeric();

        return (NumericType)type;

    }

    /**

     * Pop a type from the existing stack, ensuring that it is an integer type

     * (integer or long). Boolean type is popped as int type.

     *

     * @return the type

     */

    private BitwiseType popBitwise() {

        final Type type = popType();

        if(type == Type.BOOLEAN) {

            return Type.INT;

        }

        return (BitwiseType)type;

    }

    private BitwiseType popInteger() {

        final Type type = popType();

        if(type == Type.BOOLEAN) {

            return Type.INT;

        }

        assert type == Type.INT;

        return (BitwiseType)type;

    }

    /**

     * Pop a type from the existing stack, ensuring that it is an array type,

     * assert if not

     *

     * @return the type

     */

    private ArrayType popArray() {

        final Type type = popType();

        assert type.isArray() : type;

        return (ArrayType)type;

    }

    /**

     * Peek a given number of slots from the top of the stack and return the

     * type in that slot

     *

     * @param pos the number of positions from the top, 0 is the top element

     *

     * @return the type at position "pos" on the stack

     */

    final Type peekType(final int pos) {

        return stack.peek(pos);

    }

    /**

     * Peek at the type at the top of the stack

     *

     * @return the type at the top of the stack

     */

    final Type peekType() {

        return stack.peek();

    }

    /**

     * Generate code a for instantiating a new object and push the

     * object type on the stack

     *

     * @param classDescriptor class descriptor for the object type

     * @param type the type of the new object

     *

     * @return the method emitter

     */

    MethodEmitter _new(final String classDescriptor, final Type type) {

        debug("new", classDescriptor);

        method.visitTypeInsn(NEW, classDescriptor);

        pushType(type);

        return this;

    }

    /**

     * Generate code a for instantiating a new object and push the

     * object type on the stack

     *

     * @param clazz class type to instatiate

     *

     * @return the method emitter

     */

    MethodEmitter _new(final Class<?> clazz) {

        return _new(className(clazz), Type.typeFor(clazz));

    }

    /**

     * Generate code to call the empty constructor for a class

     *

     * @param clazz class type to instatiate

     *

     * @return the method emitter

     */

    MethodEmitter newInstance(final Class<?> clazz) {

        return invoke(constructorNoLookup(clazz));

    }

    /**

     * Perform a dup, that is, duplicate the top element and

     * push the duplicate down a given number of positions

     * on the stack. This is totally type agnostic.

     *

     * @param depth the depth on which to put the copy

     *

     * @return the method emitter, or null if depth is illegal and

     *  has no instruction equivalent.

     */

    MethodEmitter dup(final int depth) {

        if (peekType().dup(method, depth) == null) {

            return null;

        }

        debug("dup", depth);

        switch (depth) {

        case 0: {

            final int l0 = stack.getTopLocalLoad();

            pushType(peekType());

            stack.markLocalLoad(l0);

            break;

        }

        case 1: {

            final int l0 = stack.getTopLocalLoad();

            final Type p0 = popType();

            final int l1 = stack.getTopLocalLoad();

            final Type p1 = popType();

            pushType(p0);

            stack.markLocalLoad(l0);

            pushType(p1);

            stack.markLocalLoad(l1);

            pushType(p0);

            stack.markLocalLoad(l0);

            break;

        }

        case 2: {

            final int l0 = stack.getTopLocalLoad();

            final Type p0 = popType();

            final int l1 = stack.getTopLocalLoad();

            final Type p1 = popType();

            final int l2 = stack.getTopLocalLoad();

            final Type p2 = popType();

            pushType(p0);

            stack.markLocalLoad(l0);

            pushType(p2);

            stack.markLocalLoad(l2);

            pushType(p1);

            stack.markLocalLoad(l1);

            pushType(p0);

            stack.markLocalLoad(l0);

            break;

        }

        default:

            assert false : "illegal dup depth = " + depth;

            return null;

        }

        return this;

    }

    /**

     * Perform a dup2, that is, duplicate the top element if it

     * is a category 2 type, or two top elements if they are category

     * 1 types, and push them on top of the stack

     *

     * @return the method emitter

     */

    MethodEmitter dup2() {

        debug("dup2");

        if (peekType().isCategory2()) {

            final int l0 = stack.getTopLocalLoad();

            pushType(peekType());

            stack.markLocalLoad(l0);

        } else {

            final int l0 = stack.getTopLocalLoad();

            final Type p0 = popType();

            final int l1 = stack.getTopLocalLoad();

            final Type p1 = popType();

            pushType(p0);

            stack.markLocalLoad(l0);

            pushType(p1);

            stack.markLocalLoad(l1);

            pushType(p0);

            stack.markLocalLoad(l0);

            pushType(p1);

            stack.markLocalLoad(l1);

        }

        method.visitInsn(DUP2);

        return this;

    }

    /**

     * Duplicate the top element on the stack and push it

     *

     * @return the method emitter

     */

    MethodEmitter dup() {

        return dup(0);

    }

    /**

     * Pop the top element of the stack and throw it away

     *

     * @return the method emitter

     */

    MethodEmitter pop() {

        debug("pop", peekType());

        popType().pop(method);

        return this;

    }

    /**

     * Pop the top element of the stack if category 2 type, or the two

     * top elements of the stack if category 1 types

     *

     * @return the method emitter

     */

    MethodEmitter pop2() {

        if (peekType().isCategory2()) {

            popType();