Preserve frame arguments when doing OSR

Author: msimacek

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/builtins/objects/function/PArguments.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2017, 2021, Oracle and/or its affiliates.
+ * Copyright (c) 2017, 2022, Oracle and/or its affiliates.
  * Copyright (c) 2013, Regents of the University of California
  *
  * All rights reserved.
@@ -33,6 +33,7 @@
 import com.oracle.graal.python.builtins.objects.object.PythonObject;
 import com.oracle.graal.python.runtime.exception.PException;
 import com.oracle.graal.python.util.PythonUtils;
+import com.oracle.truffle.api.CompilerAsserts;
 import com.oracle.truffle.api.CompilerDirectives.ValueType;
 import com.oracle.truffle.api.Truffle;
 import com.oracle.truffle.api.frame.Frame;
@@ -279,6 +280,19 @@ public static PCell[] getClosure(Object[] arguments) {
         return (PCell[]) arguments[INDEX_CLOSURE];
     }
 
+    /*
+     * We repurpose the varargs slot for storing the OSR frame. In the bytecode interpreter, varargs
+     * should only be read once at the beginning of execute which is before OSR.
+     */
+    public static void setOSRFrame(Object[] arguments, VirtualFrame parentFrame) {
+        CompilerAsserts.neverPartOfCompilation();
+        arguments[INDEX_VARIABLE_ARGUMENTS] = parentFrame;
+    }
+
+    public static Frame getOSRFrame(Object[] arguments) {
+        return (Frame) arguments[INDEX_VARIABLE_ARGUMENTS];
+    }
+
     public static PCell[] getClosure(Frame frame) {
         return getClosure(frame.getArguments());
     }

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/nodes/bytecode/PBytecodeRootNode.java

@@ -779,6 +779,18 @@ public Object execute(VirtualFrame virtualFrame) {
         }
     }
 
+    @Override
+    public Object[] storeParentFrameInArguments(VirtualFrame parentFrame) {
+        Object[] arguments = parentFrame.getArguments();
+        PArguments.setOSRFrame(arguments, parentFrame);
+        return arguments;
+    }
+
+    @Override
+    public Frame restoreParentFrameFromArguments(Object[] arguments) {
+        return PArguments.getOSRFrame(arguments);
+    }
+
     @Override
     public Object executeOSR(VirtualFrame osrFrame, int target, Object interpreterState) {
         return executeInner(osrFrame, true, target, (Integer) interpreterState);