/*

 * Copyright (c) 2015, 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 compiler.jvmci.code;

import java.nio.ByteBuffer;

import java.nio.ByteOrder;

import java.util.ArrayList;

import java.util.Arrays;

import jdk.vm.ci.code.CodeCacheProvider;

import jdk.vm.ci.code.DebugInfo;

import jdk.vm.ci.code.Register;

import jdk.vm.ci.code.StackSlot;

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.Infopoint;

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

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

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

import jdk.vm.ci.hotspot.HotSpotCompiledCode;

import jdk.vm.ci.hotspot.HotSpotCompiledCode.Comment;

import jdk.vm.ci.hotspot.HotSpotCompiledNmethod;

import jdk.vm.ci.hotspot.HotSpotConstant;

import jdk.vm.ci.hotspot.HotSpotResolvedJavaMethod;

import jdk.vm.ci.meta.Assumptions.Assumption;

import jdk.vm.ci.meta.LIRKind;

import jdk.vm.ci.meta.PlatformKind;

import jdk.vm.ci.meta.ResolvedJavaMethod;

import jdk.vm.ci.meta.VMConstant;

/**

 * Simple assembler used by the code installation tests.

 */

public abstract class TestAssembler {

    /**

     * Emit the method prologue code (e.g. building the new stack frame).

     */

    public abstract void emitPrologue();

    /**

     * Emit code to grow the stack frame.

     *

     * @param size the size in bytes that the stack should grow

     */

    public abstract void emitGrowStack(int size);

    /**

     * Get the register containing the first 32-bit integer argument.

     */

    public abstract Register emitIntArg0();

    /**

     * Get the register containing the second 32-bit integer argument.

     */

    public abstract Register emitIntArg1();

    /**

     * Emit code to add two 32-bit integer registers. May reuse one of the argument registers.

     */

    public abstract Register emitIntAdd(Register a, Register b);

    /**

     * Emit code to load a constant 32-bit integer to a register.

     */

    public abstract Register emitLoadInt(int value);

    /**

     * Emit code to load a constant 64-bit integer to a register.

     */

    public abstract Register emitLoadLong(long value);

    /**

     * Emit code to load a constant single-precision float to a register.

     */

    public abstract Register emitLoadFloat(float value);

    /**

     * Emit code to load a constant oop or metaspace pointer to a register. The pointer may be wide

     * or narrow, depending on {@link HotSpotConstant#isCompressed() c.isCompressed()}.

     */

    public abstract Register emitLoadPointer(HotSpotConstant c);

    /**

     * Emit code to load a wide pointer from the {@link HotSpotCompiledCode#dataSection} to a

     * register.

     */

    public abstract Register emitLoadPointer(DataSectionReference ref);

    /**

     * Emit code to load a narrow pointer from the {@link HotSpotCompiledCode#dataSection} to a

     * register.

     */

    public abstract Register emitLoadNarrowPointer(DataSectionReference ref);

    /**

     * Emit code to load a (wide) pointer from a memory location to a register.

     */

    public abstract Register emitLoadPointer(Register base, int offset);

    /**

     * Emit code to store a 32-bit integer from a register to a new stack slot.

     */

    public abstract StackSlot emitIntToStack(Register a);

    /**

     * Emit code to store a 64-bit integer from a register to a new stack slot.

     */

    public abstract StackSlot emitLongToStack(Register a);

    /**

     * Emit code to store a single-precision float from a register to a new stack slot.

     */

    public abstract StackSlot emitFloatToStack(Register a);

    /**

     * Emit code to store a wide pointer from a register to a new stack slot.

     */

    public abstract StackSlot emitPointerToStack(Register a);

    /**

     * Emit code to store a narrow pointer from a register to a new stack slot.

     */

    public abstract StackSlot emitNarrowPointerToStack(Register a);

    /**

     * Emit code to uncompress a narrow pointer. The input pointer is guaranteed to be non-null.

     */

    public abstract Register emitUncompressPointer(Register compressed, long base, int shift);

    /**

     * Emit code to return from a function, returning a 32-bit integer.

     */

    public abstract void emitIntRet(Register a);

    /**

     * Emit code to return from a function, returning a wide oop pointer.

     */

    public abstract void emitPointerRet(Register a);

    /**

     * Emit code that traps, forcing a deoptimization.

     */

    public abstract void emitTrap(DebugInfo info);

    public final LIRKind narrowOopKind;

    protected final Buffer code;

    protected final Buffer data;

    private final ArrayList<Site> sites;

    private final ArrayList<DataPatch> dataPatches;

    protected final CodeCacheProvider codeCache;

    private final Register[] registers;

    private int nextRegister;

    protected int frameSize;

    private int stackAlignment;

    private int curStackSlot;

    private StackSlot deoptRescue;

    protected TestAssembler(CodeCacheProvider codeCache, int initialFrameSize, int stackAlignment, PlatformKind narrowOopKind, Register... registers) {

        this.narrowOopKind = LIRKind.reference(narrowOopKind);

        this.code = new Buffer();

        this.data = new Buffer();

        this.sites = new ArrayList<>();

        this.dataPatches = new ArrayList<>();

        this.codeCache = codeCache;

        this.registers = registers;

        this.nextRegister = 0;

        this.frameSize = initialFrameSize;

        this.stackAlignment = stackAlignment;

        this.curStackSlot = initialFrameSize;

    }

    protected Register newRegister() {

        return registers[nextRegister++];

    }

    protected StackSlot newStackSlot(LIRKind kind) {

        curStackSlot += kind.getPlatformKind().getSizeInBytes();

        if (curStackSlot > frameSize) {

            int newFrameSize = curStackSlot;

            if (newFrameSize % stackAlignment != 0) {

                newFrameSize += stackAlignment - (newFrameSize % stackAlignment);

            }

            emitGrowStack(newFrameSize - frameSize);

            frameSize = newFrameSize;

        }

        return StackSlot.get(kind, -curStackSlot, true);

    }

    protected void setDeoptRescueSlot(StackSlot deoptRescue) {

        this.deoptRescue = deoptRescue;

    }

    protected void recordImplicitException(DebugInfo info) {

        sites.add(new Infopoint(code.position(), info, InfopointReason.IMPLICIT_EXCEPTION));

    }

    protected void recordDataPatchInCode(Reference ref) {

        sites.add(new DataPatch(code.position(), ref));

    }

    protected void recordDataPatchInData(Reference ref) {

        dataPatches.add(new DataPatch(data.position(), ref));

    }

    public DataSectionReference emitDataItem(HotSpotConstant c) {

        DataSectionReference ref = new DataSectionReference();

        ref.setOffset(data.position());

        recordDataPatchInData(new ConstantReference((VMConstant) c));

        if (c.isCompressed()) {

            data.emitInt(0xDEADDEAD);

        } else {

            data.emitLong(0xDEADDEADDEADDEADL);

        }

        return ref;

    }

    public HotSpotCompiledCode finish(HotSpotResolvedJavaMethod method) {

        int id = method.allocateCompileId(0);

        byte[] finishedCode = code.finish();

        Site[] finishedSites = sites.toArray(new Site[0]);

        byte[] finishedData = data.finish();

        DataPatch[] finishedDataPatches = dataPatches.toArray(new DataPatch[0]);

        return new HotSpotCompiledNmethod(method.getName(), finishedCode, finishedCode.length, finishedSites, new Assumption[0], new ResolvedJavaMethod[]{method}, new Comment[0], finishedData, 16,

                        finishedDataPatches, false, frameSize, deoptRescue, method, 0, id, 0L, false);

    }

    protected static class Buffer {

        private ByteBuffer data = ByteBuffer.allocate(32).order(ByteOrder.nativeOrder());

        private void ensureSize(int length) {

            if (length >= data.limit()) {

                byte[] newBuf = Arrays.copyOf(data.array(), length * 4);

                ByteBuffer newData = ByteBuffer.wrap(newBuf);

                newData.order(data.order());

                newData.position(data.position());

                data = newData;

            }

        }

        public int position() {

            return data.position();

        }

        public void emitByte(int b) {

            ensureSize(data.position() + 1);

            data.put((byte) (b & 0xFF));

        }

        public void emitShort(int b) {

            ensureSize(data.position() + 2);

            data.putShort((short) b);

        }

        public void emitInt(int b) {

            ensureSize(data.position() + 4);

            data.putInt(b);

        }

        public void emitLong(long b) {

            ensureSize(data.position() + 8);

            data.putLong(b);

        }

        public void emitFloat(float f) {

            ensureSize(data.position() + 4);

            data.putFloat(f);

        }

        public void align(int alignment) {

            int pos = data.position();

            int misaligned = pos % alignment;

            if (misaligned != 0) {

                pos += alignment - misaligned;

                data.position(pos);

            }

        }

        private byte[] finish() {

            return Arrays.copyOf(data.array(), data.position());

        }

    }

}