Fix: do not implicitly assume top frame if no caller is given.

Author: fangerer

graalpython/com.oracle.graal.python.test/src/tests/test_frame_tests.py

@@ -84,6 +84,29 @@ def do_stackwalk(f):
     assert expected_prefix == actual_fnames[:len(expected_prefix)]
 
 
+def test_backref_recursive():
+    def get_frame():
+        return sys._getframe(0)
+
+    def foo(i):
+        if i == 1:
+            f = get_frame()
+            stack = []
+            while f:
+                stack.append(f)
+                f = f.f_back
+            return stack
+        else:
+            # This recursive call will cause
+            return foo(i+1)
+
+    def bar():
+        return foo(0)
+
+    s = bar()
+    print([n.f_code for n in s])
+
+
 def test_code():
     code = sys._getframe().f_code
     assert code.co_filename == test_code.__code__.co_filename

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/builtins/Python3Core.java

@@ -40,6 +40,8 @@
 import java.util.function.Supplier;
 import java.util.logging.Level;
 
+import org.graalvm.nativeimage.ImageInfo;
+
 import com.oracle.graal.python.PythonLanguage;
 import com.oracle.graal.python.builtins.modules.ArrayModuleBuiltins;
 import com.oracle.graal.python.builtins.modules.AstModuleBuiltins;
@@ -164,6 +166,7 @@
 import com.oracle.graal.python.builtins.objects.type.TypeNodes.GetNameNode;
 import com.oracle.graal.python.builtins.objects.zipimporter.ZipImporterBuiltins;
 import com.oracle.graal.python.nodes.BuiltinNames;
+import com.oracle.graal.python.nodes.call.GenericInvokeNode;
 import com.oracle.graal.python.runtime.PythonContext;
 import com.oracle.graal.python.runtime.PythonCore;
 import com.oracle.graal.python.runtime.PythonParser;
@@ -184,8 +187,6 @@
 import com.oracle.truffle.api.source.Source;
 import com.oracle.truffle.api.source.SourceSection;
 
-import org.graalvm.nativeimage.ImageInfo;
-
 /**
  * The core is intended to the immutable part of the interpreter, including most modules and most
  * types.
@@ -635,7 +636,7 @@ private void loadFile(String s, String prefix) {
             // use an anonymous module for the side-effects
             mod = factory().createPythonModule("__anonymous__");
         }
-        callTarget.call(PArguments.withGlobals(mod));
+        GenericInvokeNode.getUncached().execute(null, callTarget, PArguments.withGlobals(mod));
     }
 
     public PythonObjectFactory factory() {

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/runtime/ExecutionContext.java

@@ -195,7 +195,6 @@ public static final class CalleeContext extends Node {
         @Child private MaterializeFrameNode materializeNode;
 
         @CompilationFinal private boolean everEscaped = false;
-        @CompilationFinal private boolean firstRequest = true;
 
         /**
          * Wrap the execution of a Python callee called from a Python frame.
@@ -230,28 +229,22 @@ public void exit(VirtualFrame frame, PRootNode node) {
                 // This assumption acts as our branch profile here
                 PFrame.Reference callerInfo = PArguments.getCallerFrameInfo(frame);
                 if (callerInfo == null) {
-                    if (firstRequest) {
-                        // we didn't request the caller frame reference. now we need it.
-                        CompilerDirectives.transferToInterpreterAndInvalidate();
-                        firstRequest = false;
-
-                        // n.b. We need to use 'ReadCallerFrameNode.getCallerFrame' instead of
-                        // 'Truffle.getRuntime().getCallerFrame()' because we still need to skip
-                        // non-Python frames, even if we do not skip frames of builtin functions.
-                        Frame callerFrame = ReadCallerFrameNode.getCallerFrame(info, FrameInstance.FrameAccess.READ_ONLY, false, 0);
-                        if (PArguments.isPythonFrame(callerFrame)) {
-                            callerInfo = PArguments.getCurrentFrameInfo(callerFrame);
-                        } else {
-                            // TODO: frames: an assertion should be that this is one of our
-                            // entry point call nodes
-                            callerInfo = PFrame.Reference.EMPTY;
-                        }
+                    // we didn't request the caller frame reference. now we need it.
+                    CompilerDirectives.transferToInterpreterAndInvalidate();
+
+                    // n.b. We need to use 'ReadCallerFrameNode.getCallerFrame' instead of
+                    // 'Truffle.getRuntime().getCallerFrame()' because we still need to skip
+                    // non-Python frames, even if we do not skip frames of builtin functions.
+                    Frame callerFrame = ReadCallerFrameNode.getCallerFrame(info, FrameInstance.FrameAccess.READ_ONLY, false, 0);
+                    if (PArguments.isPythonFrame(callerFrame)) {
+                        callerInfo = PArguments.getCurrentFrameInfo(callerFrame);
                     } else {
-                        // caller info was requested, it must be here if there is
-                        // any. If it isn't, we're in a top-frame.
-                        assert node.needsCallerFrame();
+                        // TODO: frames: an assertion should be that this is one of our
+                        // entry point call nodes
                         callerInfo = PFrame.Reference.EMPTY;
                     }
+                    // ReadCallerFrameNode.getCallerFrame must have the assumption invalidated
+                    assert node.needsCallerFrame() : "stack walk did not invalidate caller frame assumption";
                 }
 
                 // force the frame so that it can be accessed later

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/runtime/PythonContext.java

@@ -52,6 +52,7 @@
 import com.oracle.graal.python.builtins.objects.common.HashingStorage;
 import com.oracle.graal.python.builtins.objects.dict.PDict;
 import com.oracle.graal.python.builtins.objects.frame.PFrame;
+import com.oracle.graal.python.builtins.objects.frame.PFrame.Reference;
 import com.oracle.graal.python.builtins.objects.list.PList;
 import com.oracle.graal.python.builtins.objects.module.PythonModule;
 import com.oracle.graal.python.builtins.objects.object.PythonObjectLibrary;
@@ -106,8 +107,11 @@ public final class PythonContext {
 
     // TODO: frame: make these three ThreadLocal
 
-    /* the reference to the last top frame on the Python stack during interop calls */
-    private PFrame.Reference topframeref = null;
+    /*
+     * The reference to the last top frame on the Python stack during interop calls. Initially, this
+     * is EMPTY representing the top frame.
+     */
+    private PFrame.Reference topframeref = Reference.EMPTY;
 
     /* corresponds to 'PyThreadState.curexc_*' */
     private PException currentException;