Fake f_lasti for started generators

Author: msimacek

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/builtins/objects/frame/FrameBuiltins.java

@@ -112,8 +112,8 @@ int get(PFrame self) {
     @GenerateNodeFactory
     public abstract static class GetLastiNode extends PythonBuiltinNode {
         @Specialization
-        int get(@SuppressWarnings("unused") PFrame self) {
-            return -1;
+        int get(PFrame self) {
+            return self.getLasti();
         }
     }
 

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/builtins/objects/frame/PFrame.java

@@ -65,6 +65,7 @@ public final class PFrame extends PythonBuiltinObject {
     private Node location;
     private RootCallTarget callTarget;
     private int line = -2;
+    private int lasti = -1;
 
     private PFrame.Reference backref = null;
 
@@ -309,4 +310,16 @@ public void setArguments(Object[] arguments2) {
     public void setLocation(Node location) {
         this.location = location;
     }
+
+    /**
+     * Last bytecode instruction. Since we don't have bytecode this is -1 by default, but can be set
+     * to a different value to distinguish started generators from unstarted
+     */
+    public int getLasti() {
+        return lasti;
+    }
+
+    public void setLasti(int lasti) {
+        this.lasti = lasti;
+    }
 }

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/builtins/objects/generator/GeneratorBuiltins.java

@@ -539,6 +539,11 @@ static Object getFrame(PGenerator self,
                 PArguments.setClosure(arguments, PArguments.getClosure(self.getArguments()));
                 PArguments.setGeneratorFrame(arguments, generatorFrame);
                 frame.setArguments(arguments);
+                if (self.isStarted()) {
+                    // Hack: Fake bytecode to make inspect.getgeneratorstate distinguish suspended
+                    // and unstarted generators
+                    frame.setLasti(10000);
+                }
                 return frame;
             }
         }