Examples with OrNode org.graalvm.compiler.nodes.calc.OrNode used on opensource projects

Example 1 with OrNode

use of org.graalvm.compiler.nodes.calc.OrNode in project graal by oracle.

the class CInterfaceInvocationPlugin method replaceBitfieldAccessor.

private boolean replaceBitfieldAccessor(GraphBuilderContext b, ResolvedJavaMethod method, ValueNode[] args, StructBitfieldInfo bitfieldInfo, AccessorInfo accessorInfo) {
    int byteOffset = bitfieldInfo.getByteOffsetInfo().getProperty();
    int startBit = bitfieldInfo.getStartBitInfo().getProperty();
    int endBit = bitfieldInfo.getEndBitInfo().getProperty();
    boolean isUnsigned = bitfieldInfo.isUnsigned();
    assert byteOffset >= 0 && byteOffset < ((SizableInfo) bitfieldInfo.getParent()).getSizeInfo().getProperty();
    assert startBit >= 0 && startBit < 8;
    assert endBit >= startBit && endBit < 64;
    /*
         * The startBit is always in the first byte. Therefore, the endBit tells us how many bytes
         * we actually have to read and write.
         */
    JavaKind memoryKind;
    if (endBit < 8) {
        memoryKind = JavaKind.Byte;
    } else if (endBit < 16) {
        memoryKind = JavaKind.Short;
    } else if (endBit < 32) {
        memoryKind = JavaKind.Int;
    } else {
        memoryKind = JavaKind.Long;
    }
    int numBytes = memoryKind.getByteCount();
    /*
         * Try to align the byteOffset to be a multiple of numBytes. That should always be possible,
         * but we don't trust the C compiler and memory layout enough to make it an assertion.
         */
    int alignmentCorrection = byteOffset % numBytes;
    if (alignmentCorrection > 0 && endBit + alignmentCorrection * 8 < numBytes * 8) {
        byteOffset -= alignmentCorrection;
        startBit += alignmentCorrection * 8;
        endBit += alignmentCorrection * 8;
    }
    assert byteOffset >= 0 && byteOffset < ((SizableInfo) bitfieldInfo.getParent()).getSizeInfo().getProperty();
    assert startBit >= 0 && startBit < numBytes * 8;
    assert endBit >= startBit && endBit < numBytes * 8;
    int numBits = endBit - startBit + 1;
    assert numBits > 0 && numBits <= numBytes * 8;
    /*
         * The bit-operations on the value are either performed on Int or Long. We do not perform 8
         * or 16 bit arithmetic operations.
         */
    JavaKind computeKind = memoryKind.getStackKind();
    Stamp computeStamp = StampFactory.forKind(computeKind);
    int computeBits = computeKind.getBitCount();
    assert startBit >= 0 && startBit < computeBits;
    assert endBit >= startBit && endBit < computeBits;
    assert computeBits >= numBits;
    assert args.length == accessorInfo.parameterCount(true);
    ValueNode base = args[accessorInfo.baseParameterNumber(true)];
    StructuredGraph graph = b.getGraph();
    /*
         * Read the memory location. This is also necessary for writes, since we need to keep the
         * bits around the written bitfield unchanged.
         */
    ValueNode address = makeAddress(graph, args, accessorInfo, base, byteOffset, -1);
    LocationIdentity locationIdentity = makeLocationIdentity(b, method, args, accessorInfo);
    Stamp stamp = StampFactory.forInteger(memoryKind.getBitCount());
    ValueNode cur = readOp(b, address, locationIdentity, stamp, accessorInfo);
    cur = adaptPrimitiveType(graph, cur, memoryKind, computeKind, true);
    switch(accessorInfo.getAccessorKind()) {
        case GETTER:
            {
                if (isUnsigned) {
                    /*
                     * Unsigned reads: shift the bitfield to the right and mask out the unnecessary
                     * high-order bits.
                     */
                    cur = graph.unique(new RightShiftNode(cur, ConstantNode.forInt(startBit, graph)));
                    cur = graph.unique(new AndNode(cur, ConstantNode.forIntegerStamp(computeStamp, (1L << numBits) - 1, graph)));
                } else {
                    /*
                     * Signed reads: shift the bitfield to the right end to get the sign bit in
                     * place, then do a signed left shift to have a proper sign extension.
                     */
                    cur = graph.unique(new LeftShiftNode(cur, ConstantNode.forInt(computeBits - endBit - 1, graph)));
                    cur = graph.unique(new RightShiftNode(cur, ConstantNode.forInt(computeBits - numBits, graph)));
                }
                JavaKind resultKind = wordTypes.asKind(b.getInvokeReturnType());
                b.push(pushKind(method), adaptPrimitiveType(graph, cur, computeKind, resultKind == JavaKind.Boolean ? resultKind : resultKind.getStackKind(), isUnsigned));
                return true;
            }
        case SETTER:
            {
                /* Zero out the bits of our bitfields, i.e., the bits we are going to change. */
                long mask = ~(((1L << numBits) - 1) << startBit);
                cur = graph.unique(new AndNode(cur, ConstantNode.forIntegerStamp(computeStamp, mask, graph)));
                /*
                 * Mask the unnecessary high-order bits of the value to be written, and shift it to
                 * its place.
                 */
                ValueNode value = args[accessorInfo.valueParameterNumber(true)];
                value = adaptPrimitiveType(graph, value, value.getStackKind(), computeKind, isUnsigned);
                value = graph.unique(new AndNode(value, ConstantNode.forIntegerStamp(computeStamp, (1L << numBits) - 1, graph)));
                value = graph.unique(new LeftShiftNode(value, ConstantNode.forInt(startBit, graph)));
                /* Combine the leftover bits of the original memory word with the new value. */
                cur = graph.unique(new OrNode(cur, value));
                /* Narrow value to the number of bits we need to write. */
                cur = adaptPrimitiveType(graph, cur, computeKind, memoryKind, true);
                /* Perform the write (bitcount is taken from the stamp of the written value). */
                writeOp(b, address, locationIdentity, cur, accessorInfo);
                return true;
            }
        default:
            throw shouldNotReachHere();
    }
}