py/mpstate: Make exceptions thread-local.

This moves mp_pending_exception from mp_state_vm_t to mp_state_thread_t.
This allows exceptions to be scheduled on a specific thread.

Signed-off-by: David Lechner <david@pybricks.com>

6 files changed, 19 insertions, 18 deletions

diff --git a/py/modthread.c b/py/modthread.c
index 64fbb3f19..29b765493 100644
--- a/py/modthread.c
+++ b/py/modthread.c
@@ -174,6 +174,8 @@ STATIC void *thread_entry(void *args_in) {
     // The GC starts off unlocked on this thread.
     ts.gc_lock_depth = 0;
 
+    ts.mp_pending_exception = MP_OBJ_NULL;
+
     // set locals and globals from the calling context
     mp_locals_set(args->dict_locals);
     mp_globals_set(args->dict_globals);
@@ -184,7 +186,6 @@ STATIC void *thread_entry(void *args_in) {
     mp_thread_start();
 
     // TODO set more thread-specific state here:
-    //  mp_pending_exception? (root pointer)
     //  cur_exception (root pointer)
 
     DEBUG_printf("[thread] start ts=%p args=%p stack=%p\n", &ts, &args, MP_STATE_THREAD(stack_top));
diff --git a/py/mpstate.h b/py/mpstate.h
index a0e3d4f14..f5fb5b707 100644
--- a/py/mpstate.h
+++ b/py/mpstate.h
@@ -137,9 +137,6 @@ typedef struct _mp_state_vm_t {
     // dictionary with loaded modules (may be exposed as sys.modules)
     mp_obj_dict_t mp_loaded_modules_dict;
 
-    // pending exception object (MP_OBJ_NULL if not pending)
-    volatile mp_obj_t mp_pending_exception;
-
     #if MICROPY_ENABLE_SCHEDULER
     mp_sched_item_t sched_queue[MICROPY_SCHEDULER_DEPTH];
     #endif
@@ -266,6 +263,9 @@ typedef struct _mp_state_thread_t {
 
     nlr_buf_t *nlr_top;
 
+    // pending exception object (MP_OBJ_NULL if not pending)
+    volatile mp_obj_t mp_pending_exception;
+
     #if MICROPY_PY_SYS_SETTRACE
     mp_obj_t prof_trace_callback;
     bool prof_callback_is_executing;
diff --git a/py/profile.c b/py/profile.c
index e5fb35f0e..054a0f9e6 100644
--- a/py/profile.c
+++ b/py/profile.c
@@ -297,7 +297,7 @@ STATIC mp_obj_t mp_prof_callback_invoke(mp_obj_t callback, prof_callback_args_t
 
     mp_prof_is_executing = false;
 
-    if (MP_STATE_VM(mp_pending_exception) != MP_OBJ_NULL) {
+    if (MP_STATE_THREAD(mp_pending_exception) != MP_OBJ_NULL) {
         mp_handle_pending(true);
     }
     return top;
diff --git a/py/runtime.c b/py/runtime.c
index 1ca0702e1..cda26a9cf 100644
--- a/py/runtime.c
+++ b/py/runtime.c
@@ -62,7 +62,7 @@ void mp_init(void) {
     qstr_init();
 
     // no pending exceptions to start with
-    MP_STATE_VM(mp_pending_exception) = MP_OBJ_NULL;
+    MP_STATE_THREAD(mp_pending_exception) = MP_OBJ_NULL;
     #if MICROPY_ENABLE_SCHEDULER
     MP_STATE_VM(sched_state) = MP_SCHED_IDLE;
     MP_STATE_VM(sched_idx) = 0;
diff --git a/py/scheduler.c b/py/scheduler.c
index 0671a34a8..0114a7a58 100644
--- a/py/scheduler.c
+++ b/py/scheduler.c
@@ -29,7 +29,7 @@
 #include "py/runtime.h"
 
 void MICROPY_WRAP_MP_SCHED_EXCEPTION(mp_sched_exception)(mp_obj_t exc) {
-    MP_STATE_VM(mp_pending_exception) = exc;
+    MP_STATE_THREAD(mp_pending_exception) = exc;
     #if MICROPY_ENABLE_SCHEDULER
     if (MP_STATE_VM(sched_state) == MP_SCHED_IDLE) {
         MP_STATE_VM(sched_state) = MP_SCHED_PENDING;
@@ -66,9 +66,9 @@ void mp_handle_pending(bool raise_exc) {
         mp_uint_t atomic_state = MICROPY_BEGIN_ATOMIC_SECTION();
         // Re-check state is still pending now that we're in the atomic section.
         if (MP_STATE_VM(sched_state) == MP_SCHED_PENDING) {
-            mp_obj_t obj = MP_STATE_VM(mp_pending_exception);
+            mp_obj_t obj = MP_STATE_THREAD(mp_pending_exception);
             if (obj != MP_OBJ_NULL) {
-                MP_STATE_VM(mp_pending_exception) = MP_OBJ_NULL;
+                MP_STATE_THREAD(mp_pending_exception) = MP_OBJ_NULL;
                 if (!mp_sched_num_pending()) {
                     MP_STATE_VM(sched_state) = MP_SCHED_IDLE;
                 }
@@ -115,7 +115,7 @@ void mp_sched_unlock(void) {
     assert(MP_STATE_VM(sched_state) < 0);
     if (++MP_STATE_VM(sched_state) == 0) {
         // vm became unlocked
-        if (MP_STATE_VM(mp_pending_exception) != MP_OBJ_NULL || mp_sched_num_pending()) {
+        if (MP_STATE_THREAD(mp_pending_exception) != MP_OBJ_NULL || mp_sched_num_pending()) {
             MP_STATE_VM(sched_state) = MP_SCHED_PENDING;
         } else {
             MP_STATE_VM(sched_state) = MP_SCHED_IDLE;
@@ -148,9 +148,9 @@ bool MICROPY_WRAP_MP_SCHED_SCHEDULE(mp_sched_schedule)(mp_obj_t function, mp_obj
 
 // A variant of this is inlined in the VM at the pending exception check
 void mp_handle_pending(bool raise_exc) {
-    if (MP_STATE_VM(mp_pending_exception) != MP_OBJ_NULL) {
-        mp_obj_t obj = MP_STATE_VM(mp_pending_exception);
-        MP_STATE_VM(mp_pending_exception) = MP_OBJ_NULL;
+    if (MP_STATE_THREAD(mp_pending_exception) != MP_OBJ_NULL) {
+        mp_obj_t obj = MP_STATE_THREAD(mp_pending_exception);
+        MP_STATE_THREAD(mp_pending_exception) = MP_OBJ_NULL;
         if (raise_exc) {
             nlr_raise(obj);
         }
diff --git a/py/vm.c b/py/vm.c
index c97070b78..f9a589c9d 100644
--- a/py/vm.c
+++ b/py/vm.c
@@ -1375,9 +1375,9 @@ pending_exception_check:
                     // Re-check state is still pending now that we're in the atomic section.
                     if (MP_STATE_VM(sched_state) == MP_SCHED_PENDING) {
                         MARK_EXC_IP_SELECTIVE();
-                        mp_obj_t obj = MP_STATE_VM(mp_pending_exception);
+                        mp_obj_t obj = MP_STATE_THREAD(mp_pending_exception);
                         if (obj != MP_OBJ_NULL) {
-                            MP_STATE_VM(mp_pending_exception) = MP_OBJ_NULL;
+                            MP_STATE_THREAD(mp_pending_exception) = MP_OBJ_NULL;
                             if (!mp_sched_num_pending()) {
                                 MP_STATE_VM(sched_state) = MP_SCHED_IDLE;
                             }
@@ -1391,10 +1391,10 @@ pending_exception_check:
                 }
                 #else
                 // This is an inlined variant of mp_handle_pending
-                if (MP_STATE_VM(mp_pending_exception) != MP_OBJ_NULL) {
+                if (MP_STATE_THREAD(mp_pending_exception) != MP_OBJ_NULL) {
                     MARK_EXC_IP_SELECTIVE();
-                    mp_obj_t obj = MP_STATE_VM(mp_pending_exception);
-                    MP_STATE_VM(mp_pending_exception) = MP_OBJ_NULL;
+                    mp_obj_t obj = MP_STATE_THREAD(mp_pending_exception);
+                    MP_STATE_THREAD(mp_pending_exception) = MP_OBJ_NULL;
                     RAISE(obj);
                 }
                 #endif