add back trashcan macros

from_cpython/Include/object.h

@@ -1054,9 +1054,6 @@ PyAPI_FUNC(void) _PyTrash_thread_destroy_chain(void) PYSTON_NOEXCEPT;
 
 #define PyTrash_UNWIND_LEVEL 50
 
-// Pyston change: I don't think we need this since destructors
-// are run differently
-#if 0
 /* Note the workaround for when the thread state is NULL (issue #17703) */
 #define Py_TRASHCAN_SAFE_BEGIN(op) \
     do { \
@@ -1077,9 +1074,6 @@ PyAPI_FUNC(void) _PyTrash_thread_destroy_chain(void) PYSTON_NOEXCEPT;
         else \
             _PyTrash_thread_deposit_object((PyObject*)op); \
     } while (0);
-#endif
-#define Py_TRASHCAN_SAFE_BEGIN(op) do {
-#define Py_TRASHCAN_SAFE_END(op) } while (0);
 
 #ifdef __cplusplus
 }

from_cpython/Include/pystate.h

@@ -120,6 +120,9 @@ typedef struct _ts {
 
     PyObject *dict;  /* Stores per-thread state */
 
+    int trash_delete_nesting;
+    PyObject *trash_delete_later;
+
     // Pyston note: additions in here need to be mirrored in ThreadStateInternal::accept
 } PyThreadState;
 

src/capi/object.cpp

@@ -1108,4 +1108,11 @@ extern "C" void _Py_NegativeRefcount(const char* fname, int lineno, PyObject* op
 }
 
 #endif /* Py_REF_DEBUG */
+
+extern "C" void _PyTrash_thread_deposit_object(PyObject* op) noexcept {
+    Py_FatalError("unimplemented");
+}
+extern "C" void _PyTrash_thread_destroy_chain() noexcept {
+    Py_FatalError("unimplemented");
+}
 }

src/core/threading.cpp

@@ -38,7 +38,7 @@ std::unordered_set<PerThreadSetBase*> PerThreadSetBase::all_instances;
 
 extern "C" {
 __thread PyThreadState cur_thread_state
-    = { 0, 1, NULL, NULL, NULL, NULL }; // not sure if we need to explicitly request zero-initialization
+    = { 0, 1, NULL, NULL, NULL, NULL, 0, NULL }; // not sure if we need to explicitly request zero-initialization
 }
 
 PthreadFastMutex threading_lock;
@@ -142,6 +142,8 @@ public:
             v->visit(&pub_state->curexc_traceback);
         if (pub_state->dict)
             v->visit(&pub_state->dict);
+        if (pub_state->trash_delete_later)
+            v->visit(&pub_state->trash_delete_later);
 
         for (auto& stack_info : previous_stacks) {
             v->visit(&stack_info.next_generator);