methodcode.java

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/**
  * Abstract class to support code for methods
  * @version $Id: MethodCode.java,v 1.7 1998/12/30 15:57:29 pab Exp $
  * @author Peter A. Bigot
  *
  * Roughly corresponds to a C generic method structure mt_generic, but may
  * have additional information required for code generation.  It is
  * expected that this will be extended by specific implementations: the
  * interpreter code generator, or the JIT code generator, etc.
  */

/* This is part of the classfile component of the Toba system */
package toba.classfile;

public class MethodCode {
    /* Toba method source type: tell us where the method came from.
     * I suppose one could probably dig this out from the class loader,
     * if one wanted to.  The values here should match those in the
     * runtime toba.h file for the TobaMethodInvokerType enumeration. */
    static final int TMIT_undefined = 0; /* Unknown method */
    static final int TMIT_native_code = 1; /* Native code invocation */
    static final int TMIT_interpreter = 2; /* Call interpreter to execute */
    static final int TMIT_uninstalled_jit = 3; /* Need to compile this */
    static final int TMIT_abstract = 4; /* Unreachable abstract method */
    static int TMIT_LAST_ENUM = 4; /* Last assigned TMIT value */

    protected int itype;        // Tag indicating source of this method's code
    protected long mtentry;     // Java representation of function entry point 
    protected long stbentry;    // Java representation of function resolver stub entry point
    protected boolean isResolved; // Has this been linked yet?
    public Method method;       // The method to which the code belongs

    public static boolean shouldTimeCodegen;
    static {
        shouldTimeCodegen = (null != System.getProperty ("jtoba_timeCodegen"));
    }

    public int compileTime = 0; // Time taken to convert JVM to assembly code
    public int resolveTime = 0; // Time taken to resolve references in assembly code

    /** Create a new MethodCode instance belonging to given method
      * @param m the method to which the code belongs
      */
    public
    MethodCode (Method m) {     // Who wants code?
        /* Start out with an undefined type, no function pointer, and
         * mark it unlinked. */
        itype = TMIT_undefined;
        mtentry = 0;
        isResolved = false;
        method = m;
    }

    /** Set the method code type
      * @param it an integer value from the TMIT_* suite
      * @returns the parameter it
      */
    public int
    setMethodType (int it)      // Method code source/type tag
    {
        itype = it;
        return itype;
    }
    /** Retrieve the method code type
      * @returns the code tag for this MethodCode instance
    public int
    getMethodType ()
    {
        return itype;
    }

    /** Set the method code function entry point
      * @param fp address of native code function, cast to long
      * @returns the parameter fp
      */
    public long
    setMethodEntry (long fp)    // Where to call for this code
    {
        mtentry = fp;
        return mtentry;
    }
    /** Retrieve the method code function final entry point (never the
      * stub entry point).
      * @returns the method code function entry point
      */
    public long
    getMethodEntry ()
    {
        return mtentry;
    }

    /** Retrieve the current method entry point, which is the real entry
      * point if it's been resolved, and the stub entry point if not.
      * @returns address of code to (resolve and) execute the method. */
    public long
    getEntryPoint ()
    {
        return isResolved ? mtentry : stbentry;
    }

    /** Set the method code stub entry point
      * @param fp address of native code function, cast to long
      * @returns the parameter fp
      */
    public long
    setStubEntry (long fp)    // Where to call for this code
    {
        stbentry = fp;
        return stbentry;
    }
    /** Retrieve the method code stub entry point
      * @returns the method code stub entry point
      */
    public long
    getStubEntry ()
    {
        return stbentry;
    }

    public boolean
    getIsResolved () {
        return isResolved;
    }

    /** Do any linking that's necessary to complete code generation.
      * This should be overridden if a particular compilation type has a
      * nontrivial resolution action. */
    public void
    resolveCode ()
    {
        if (isResolved) {
            /* Already done this. */
            return;
        }
        isResolved = true;
        return;
    }
}