[Python-checkins] Remove PyTryblock struct (GH-26059)

[markshannon]

https://github.com/python/cpython/commit/117bfd2b7141127b18d5ca4d6bbc4b3068bbce33
commit: 117bfd2b7141127b18d5ca4d6bbc4b3068bbce33
branch: main
author: Mark Shannon <mark at hotpy.org>
committer: markshannon <mark at hotpy.org>
date: 2021-05-12T14:04:38+01:00
summary:

Remove PyTryblock struct (GH-26059)

files:
M Include/cpython/frameobject.h
M Python/ceval.c

diff --git a/Include/cpython/frameobject.h b/Include/cpython/frameobject.h
index 0c2206c0b92b6d..581664775cdedc 100644
--- a/Include/cpython/frameobject.h
+++ b/Include/cpython/frameobject.h
@@ -19,12 +19,6 @@ enum _framestate {
 
 typedef signed char PyFrameState;
 
-typedef struct {
-    int b_type;                 /* what kind of block this is */
-    int b_handler;              /* where to jump to find handler */
-    int b_level;                /* value stack level to pop to */
-} PyTryBlock;
-
 struct _frame {
     PyObject_VAR_HEAD
     struct _frame *f_back;      /* previous frame, or NULL */
diff --git a/Python/ceval.c b/Python/ceval.c
index 8e1c5bdf033074..2e15eea48003e0 100644
--- a/Python/ceval.c
+++ b/Python/ceval.c
@@ -95,7 +95,7 @@ static PyObject * special_lookup(PyThreadState *, PyObject *, _Py_Identifier *);
 static int check_args_iterable(PyThreadState *, PyObject *func, PyObject *vararg);
 static void format_kwargs_error(PyThreadState *, PyObject *func, PyObject *kwargs);
 static void format_awaitable_error(PyThreadState *, PyTypeObject *, int, int);
-static PyTryBlock get_exception_handler(PyCodeObject *, int);
+static int get_exception_handler(PyCodeObject *, int, int*, int*, int*);
 
 #define NAME_ERROR_MSG \
     "name '%.200s' is not defined"
@@ -4461,21 +4461,20 @@ _PyEval_EvalFrameDefault(PyThreadState *tstate, PyFrameObject *f, int throwflag)
 exception_unwind:
         f->f_state = FRAME_UNWINDING;
         /* We can't use f->f_lasti here, as RERAISE may have set it */
-        int lasti = INSTR_OFFSET()-1;
-        PyTryBlock from_table = get_exception_handler(co, lasti);
-        if (from_table.b_handler < 0) {
+        int offset = INSTR_OFFSET()-1;
+        int level, handler, lasti;
+        if (get_exception_handler(co, offset, &level, &handler, &lasti) == 0) {
             // No handlers, so exit.
             break;
         }
 
-        assert(STACK_LEVEL() >= from_table.b_level);
-        while (STACK_LEVEL() > from_table.b_level) {
+        assert(STACK_LEVEL() >= level);
+        while (STACK_LEVEL() > level) {
             PyObject *v = POP();
             Py_XDECREF(v);
         }
         PyObject *exc, *val, *tb;
-        int handler = from_table.b_handler;
-        if (from_table.b_type) {
+        if (lasti) {
             PyObject *lasti = PyLong_FromLong(f->f_lasti);
             if (lasti == NULL) {
                 goto exception_unwind;
@@ -4811,21 +4810,11 @@ parse_range(unsigned char *p, int *start, int*end)
     return p;
 }
 
-static inline void
-parse_block(unsigned char *p, PyTryBlock *block) {
-    int depth_and_lasti;
-    p = parse_varint(p, &block->b_handler);
-    p = parse_varint(p, &depth_and_lasti);
-    block->b_level = depth_and_lasti >> 1;
-    block->b_type = depth_and_lasti & 1;
-}
-
 #define MAX_LINEAR_SEARCH 40
 
-static PyTryBlock
-get_exception_handler(PyCodeObject *code, int index)
+static int
+get_exception_handler(PyCodeObject *code, int index, int *level, int *handler, int *lasti)
 {
-    PyTryBlock res;
     unsigned char *start = (unsigned char *)PyBytes_AS_STRING(code->co_exceptiontable);
     unsigned char *end = start + PyBytes_GET_SIZE(code->co_exceptiontable);
     /* Invariants:
@@ -4837,8 +4826,7 @@ get_exception_handler(PyCodeObject *code, int index)
         int offset;
         parse_varint(start, &offset);
         if (offset > index) {
-            res.b_handler = -1;
-            return res;
+            return 0;
         }
         do {
             unsigned char * mid = start + ((end-start)>>1);
@@ -4862,13 +4850,16 @@ get_exception_handler(PyCodeObject *code, int index)
         }
         scan = parse_varint(scan, &size);
         if (start_offset + size > index) {
-            parse_block(scan, &res);
-            return res;
+            scan = parse_varint(scan, handler);
+            int depth_and_lasti;
+            parse_varint(scan, &depth_and_lasti);
+            *level = depth_and_lasti >> 1;
+            *lasti = depth_and_lasti & 1;
+            return 1;
         }
         scan = skip_to_next_entry(scan, end);
     }
-    res.b_handler = -1;
-    return res;
+    return 0;
 }
 
 PyFrameObject *