Avoid an uncached PRaiseNode when entering Context

Author: Adam Hrbac

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/builtins/objects/contextvars/ContextBuiltins.java

@@ -85,9 +85,10 @@ Object get(PContextVarsContext self, Object key,
     public abstract static class Run extends PythonBuiltinNode {
         @Specialization
         Object get(VirtualFrame frame, PContextVarsContext self, Object fun, Object[] args, PKeyword[] keywords,
-                        @Cached CallNode call) {
+                        @Cached CallNode call,
+                        @Cached PRaiseNode raise) {
             PythonContext.PythonThreadState threadState = getContext().getThreadState(getLanguage());
-            self.enter(threadState);
+            self.enter(threadState, raise);
             try {
                 return call.execute(frame, fun, args, keywords);
             } finally {

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/builtins/objects/contextvars/PContextVarsContext.java

@@ -51,9 +51,9 @@ public class PContextVarsContext extends PythonBuiltinObject {
     Hamt contextVarValues;
     private PContextVarsContext previousContext = null;
 
-    public void enter(PythonContext.PythonThreadState threadState) {
+    public void enter(PythonContext.PythonThreadState threadState, PRaiseNode raise) {
         if (previousContext != null) {
-            throw PRaiseNode.getUncached().raise(PythonBuiltinClassType.RuntimeError, ErrorMessages.CANNOT_ENTER_CONTEXT_ALREADY_ENTERED, this);
+            throw raise.raise(PythonBuiltinClassType.RuntimeError, ErrorMessages.CANNOT_ENTER_CONTEXT_ALREADY_ENTERED, this);
         }
         previousContext = threadState.getContextVarsContext();
         assert previousContext != null : "ThreadState had null Context. This should not happen";