kilim.analysis

Class CallWeaver

java.lang.Object

kilim.analysis.CallWeaver

public class CallWeaver
extends java.lang.Object

This class produces all the code associated with a specific pausable method invocation. There are three distinct chunks of code.

Rewind: At the beginning of the method, right after the opening switch statement (switch fiber.pc), which is the "rewind" portion. This stage pushes in (mostly) dummy values on the stack and jumps to the next method invocation in the cycle.

Call: The actual call. We push fiber as the last argument to the pausable method (by calling fiber.down()), before making the call.

Post-call The bulk of the code produced by this object.

An explanation of some terms used in the code may be useful. Much of this code concerns itself with storing and retrieving values from/to the stack and the local variables. The stack consists of three logical parts:

   +--------------+----------------------+---------------+
   | Stack bottom | callee obj reference | args for call | (Top of stack)
   +--------------+----------------------+---------------+
 

The callee's object reference and the arguments at the top of stack are consumed by the method invocation. If the call is static, there is no object reference, of course. The bottom of the stack (which may also be empty) refers to the part of the stack that is left over once the args are consumed. This is the part that we need to save if we have to yield.

As for the local variables, we are interested in saving var 0 (the "this" pointer) and all other variables that the flow analysis has shown to be live-in, that is, is used downstream of the call. Typically, only about 30% of all available vars are actually used downstream, so we use the rest for temporary storage.

See Also:

genRewind(MethodVisitor), genCall(MethodVisitor), genPostCall(MethodVisitor)

Constructor Summary

Constructors

Constructor and Description
CallWeaver(MethodWeaver mw, Detector d, BasicBlock aBB)

Method Summary

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

CallWeaver

public CallWeaver(MethodWeaver mw,
                  Detector d,
                  BasicBlock aBB)