This is Armin Rigo's patch:

[ 617312 ] debugger-controlled jumps (Psyco #3)

Forward port candidate, I guess.

diff --git a/Python/ceval.c b/Python/ceval.c
index 9db5b023afdfd697f463f98ed29ec71f3d9af65e..e8fefca8a8cc7a24e49d068bb312496747b2d62a 100644 (file)
--- a/Python/ceval.c
+++ b/Python/ceval.c
@@ -585,14 +585,6 @@ eval_frame(PyFrameObject *f)
        }
 
        tstate->frame = f;
-       co = f->f_code;
-       fastlocals = f->f_localsplus;
-       freevars = f->f_localsplus + f->f_nlocals;
-       _PyCode_GETCODEPTR(co, &first_instr);
-       next_instr = first_instr + f->f_lasti;
-       stack_pointer = f->f_stacktop;
-       assert(stack_pointer != NULL);
-       f->f_stacktop = NULL;   /* remains NULL unless yield suspends frame */
 
        if (tstate->use_tracing) {
                if (tstate->c_tracefunc != NULL) {
@@ -631,6 +623,15 @@ eval_frame(PyFrameObject *f)
                }
        }
 
+       co = f->f_code;
+       fastlocals = f->f_localsplus;
+       freevars = f->f_localsplus + f->f_nlocals;
+       _PyCode_GETCODEPTR(co, &first_instr);
+       next_instr = first_instr + f->f_lasti;
+       stack_pointer = f->f_stacktop;
+       assert(stack_pointer != NULL);
+       f->f_stacktop = NULL;   /* remains NULL unless yield suspends frame */
+
 #ifdef LLTRACE
        lltrace = PyDict_GetItemString(f->f_globals,"__lltrace__") != NULL;
 #endif
@@ -1972,6 +1973,7 @@ eval_frame(PyFrameObject *f)
                                continue;
                        /* Trace each line of code reached */
                        f->f_lasti = INSTR_OFFSET();
+                       f->f_stacktop = stack_pointer;
                        /* Inline call_trace() for performance: */
                        tstate->tracing++;
                        tstate->use_tracing = 0;
@@ -1980,6 +1982,11 @@ eval_frame(PyFrameObject *f)
                        tstate->use_tracing = (tstate->c_tracefunc
                                               || tstate->c_profilefunc);
                        tstate->tracing--;
+                       /* Reload possibly changed frame fields */
+                       JUMPTO(f->f_lasti);
+                       stack_pointer = f->f_stacktop;
+                       assert(stack_pointer != NULL);
+                       f->f_stacktop = NULL;
                        break;
 
                case CALL_FUNCTION: