org.qbicc.graph.Terminator Maven / Gradle / Ivy

Go to download

Show more of this group Show more artifacts with this name
Show all versions of qbicc-compiler Show documentation

The main Qbicc compiler

There is a newer version: 0.77.0

package org.qbicc.graph;

import java.util.NoSuchElementException;
import java.util.Set;

/**
 * A construct which terminates a block.  It holds a dependency on the preceding sequence of inter-thread actions.
 */
public interface Terminator extends OrderedNode {
     R accept(TerminatorVisitor visitor, T param);

    BasicBlock getTerminatedBlock();

    default int getSuccessorCount() {
        return 0;
    }

    default BasicBlock getSuccessor(int index) {
        throw new IndexOutOfBoundsException(index);
    }

    /**
     * Get the outbound argument for the given block parameter slot, to be passed into any successor block.
     * Terminators which do not pass control flow to a successor block should return an empty map.
     * The terminator must establish a value dependency on each value propagated as an outbound argument.
     *
     * @param slot the slot (must not be {@code null})
     * @return the argument (not {@code null})
     * @throws NoSuchElementException if there is no outbound argument specified for the given slot
     */
    default Value getOutboundArgument(Slot slot) throws NoSuchElementException {
        throw new NoSuchElementException();
    }

    /**
     * Determine whether this terminator node creates an implicit value for the given slot.
     *
     * @param slot the slot (must not be {@code null})
     * @param block the block receiving the outbound argument (must not be {@code null})
     * @return {@code true} if the slot corresponds to an implicit outbound argument, or {@code false} otherwise
     */
    default boolean isImplicitOutboundArgument(Slot slot, BasicBlock block) {
        return false;
    }

    /**
     * Get the set of outbound argument names, in no particular order.
     *
     * @return the names set (not {@code null})
     */
    default Set getOutboundArgumentNames() {
        return Set.of();
    }
}