Use tagged refs and dump more info in lltrace

Author: markshannon

Python/bytecodes.c

@@ -244,7 +244,8 @@ dummy_func(
 
         inst(LOAD_FAST_DEFERRED, (-- value)) {
             assert(!PyStackRef_IsNull(GETLOCAL(oparg)));
-            value = PyStackRef_DUP(GETLOCAL(oparg));
+            value = GETLOCAL(oparg);
+            value.bits |= Py_TAG_REFCNT;
         }
 
         inst(LOAD_FAST_AND_CLEAR, (-- value)) {

Python/ceval.c

@@ -136,39 +136,53 @@
 
 
 #ifdef LLTRACE
+static void print_item(_PyStackRef ref)
+{
+    if (PyStackRef_IsNull(ref)) {
+        printf("<NULL>");
+        return;
+    }
+    PyObject *obj = PyStackRef_AsPyObjectBorrow(ref);
+    if (obj == NULL) {
+        printf("<nil>");
+        return;
+    }
+    if (
+        obj == Py_None
+        || PyBool_Check(obj)
+        || PyLong_CheckExact(obj)
+        || PyFloat_CheckExact(obj)
+        || PyUnicode_CheckExact(obj)
+    ) {
+        if (PyObject_Print(obj, stdout, 0) == 0) {
+            return;
+        }
+        PyErr_Clear();
+    }
+    // Don't call __repr__(), it might recurse into the interpreter.
+    printf("<%s at %p>", Py_TYPE(obj)->tp_name, (void *)(ref.bits));
+}
+
 static void
 dump_stack(_PyInterpreterFrame *frame, _PyStackRef *stack_pointer)
 {
+    _PyStackRef *locals_base = _PyFrame_GetLocalsArray(frame);
     _PyStackRef *stack_base = _PyFrame_Stackbase(frame);
     PyObject *exc = PyErr_GetRaisedException();
+    printf("    locals=[");
+    for (_PyStackRef *ptr = locals_base; ptr < stack_base; ptr++) {
+        if (ptr != locals_base) {
+            printf(", ");
+        }
+        print_item(*ptr);
+    }
+    printf("]\n");
     printf("    stack=[");
     for (_PyStackRef *ptr = stack_base; ptr < stack_pointer; ptr++) {
         if (ptr != stack_base) {
             printf(", ");
         }
-        if (PyStackRef_IsNull(*ptr)) {
-            printf("<NULL>");
-            continue;
-        }
-        PyObject *obj = PyStackRef_AsPyObjectBorrow(*ptr);
-        if (obj == NULL) {
-            printf("<nil>");
-            continue;
-        }
-        if (
-            obj == Py_None
-            || PyBool_Check(obj)
-            || PyLong_CheckExact(obj)
-            || PyFloat_CheckExact(obj)
-            || PyUnicode_CheckExact(obj)
-        ) {
-            if (PyObject_Print(obj, stdout, 0) == 0) {
-                continue;
-            }
-            PyErr_Clear();
-        }
-        // Don't call __repr__(), it might recurse into the interpreter.
-        printf("<%s at %p>", Py_TYPE(obj)->tp_name, (void *)(ptr->bits));
+        print_item(*ptr);
     }
     printf("]\n");
     fflush(stdout);
@@ -253,6 +267,7 @@ maybe_lltrace_resume_frame(_PyInterpreterFrame *frame, _PyInterpreterFrame *skip
             lltrace = *python_lltrace - '0';  // TODO: Parse an int and all that
         }
     }
+    lltrace = 5;
     if (lltrace >= 5) {
         lltrace_resume_frame(frame);
     }

Python/executor_cases.c.h

@@ -68,7 +68,7 @@ take_ownership(PyFrameObject *f, _PyInterpreterFrame *frame)
     assert(!_PyFrame_IsIncomplete(frame));
     assert(f->f_back == NULL);
     _PyInterpreterFrame *prev = _PyFrame_GetFirstComplete(frame->previous);
-    frame->previous = NULL;
+    frame->previous = NULLBINARY_OP_ADD_UNICODE;
     if (prev) {
         assert(prev->owner != FRAME_OWNED_BY_CSTACK);
         /* Link PyFrameObjects.f_back and remove link through _PyInterpreterFrame.previous */