added Code.java

darcs-hash:20050603073955-5007d-8f78a752966e530769102b8cafe6b9e080641405.gz

diff --git a/src/org/ibex/classgen/Code.java b/src/org/ibex/classgen/Code.java
new file mode 100644 (file)
index 0000000..22c8fc6
--- /dev/null
+++ b/src/org/ibex/classgen/Code.java
@@ -0,0 +1,74 @@
+package org.ibex.classgen;
+public class Code {
+
+    /**
+     *  This should actually be called "ValueProducer", but that
+     *  requires more typing.
+     *
+     *  A Value is anything that generates an item on the stack.
+     *  Every instruction that causes something new to appear on the
+     *  stack implements Value.  Every instruction that uses
+     *  something(s) on the stack will hold a reference to the thing
+     *  (almost always an instruction) that generates the thing(s) it
+     *  removes from the stack.
+     */
+    public interface Value {
+        // commented out so that the rest of this file compiles
+        // Instruction[] getUsers();
+    }
+
+    /**
+     *  A "nondeterministic box" -- for example when the first
+     *  instruction in a loop reads from a local which could have been
+     *  written to either by some instruction at the end of the
+     *  previous iteration of the loop or by some instruction before
+     *  the loop (on the first iteration).
+     */
+    public class Phi implements Value {
+        public Phi(Value[] inputs) { }
+        public Instruction[] getUsers() { return null; /* FIXME */ }
+    }
+
+    /** any instruction which does not -- by itself -- remove anything from the stack */
+    public class Instruction { }
+
+    /** any instruction that consumes one item from the stack */
+    public class OneOp           extends Instruction { Value in;  }
+
+    /** any instruction that consumes two items from the stack */
+    public class TwoOp           extends Instruction { Value in1, in2; }
+    
+    /** a sequence of instructions */
+    public class Sequence        extends Instruction { Instruction[] code; }
+    public class Monitor         extends Sequence    { Value objectToSynchronizeOn; }
+    public class TryCatchFinally extends Sequence    { OneOp[] catchBodies;  Instruction finallyBody; }
+
+    public class Goto            extends Instruction                  { Instruction target; }
+    public class JSR             extends Instruction implements Value { Instruction target; }
+    public class Ret             extends OneOp                        { }
+    public class Nop             extends Instruction                  { }
+
+    public class Constant        extends Instruction implements Value { /** ??? **/ }
+    public class LDC             extends Instruction implements Value { Type.Class klass; }
+    public class New             extends Instruction implements Value { Type.Ref   type; }
+    public class ArrayLength     extends OneOp       implements Value { }
+    public class ArrayIndex      extends Instruction implements Value { }
+    public class Return          extends OneOp                        { }
+    public class ReturnVoid      extends Instruction                  { }
+    public class CheckCast       extends OneOp       implements Value { Type.Ref   castTarget; }
+    public class Instanceof      extends OneOp       implements Value { Type.Class klass; }
+    public class If              extends OneOp                        { Instruction thenTarget, elseTarget; }
+    public class Switch          extends OneOp {
+        public class Table extends Switch { }
+        public class Lookup extends Switch { }
+    }
+
+    public abstract class Invoke extends Instruction {
+        Value[] arguments;
+        Type.Class.Method method;
+        public class Static  extends Invoke implements Value { }
+        public class Special extends Invoke implements Value { }
+        public class Virtual extends Invoke implements Value { Value instance; }
+    }
+
+}