Add immortality test to symbols

Author: markshannon

Include/internal/pycore_optimizer.h

@@ -289,7 +289,7 @@ extern void _Py_uop_sym_set_const(JitOptContext *ctx, JitOptSymbol *sym, PyObjec
 extern bool _Py_uop_sym_is_bottom(JitOptSymbol *sym);
 extern int _Py_uop_sym_truthiness(JitOptSymbol *sym);
 extern PyTypeObject *_Py_uop_sym_get_type(JitOptSymbol *sym);
-
+extern bool _Py_uop_sym_is_immortal(JitOptSymbol *sym);
 extern JitOptSymbol *_Py_uop_sym_new_tuple(JitOptContext *ctx, int size, JitOptSymbol **args);
 extern JitOptSymbol *_Py_uop_sym_tuple_getitem(JitOptContext *ctx, JitOptSymbol *sym, int item);
 extern int _Py_uop_sym_tuple_length(JitOptSymbol *sym);

Python/optimizer_analysis.c

@@ -371,6 +371,7 @@ remove_globals(_PyInterpreterFrame *frame, _PyUOpInstruction *buffer,
 #define sym_new_tuple _Py_uop_sym_new_tuple
 #define sym_tuple_getitem _Py_uop_sym_tuple_getitem
 #define sym_tuple_length _Py_uop_sym_tuple_length
+#define sym_is_immortal _Py_uop_sym_is_immortal
 
 static int
 optimize_to_bool(

Python/optimizer_bytecodes.c

@@ -33,6 +33,7 @@ typedef struct _Py_UOpsAbstractFrame _Py_UOpsAbstractFrame;
 #define sym_new_tuple _Py_uop_sym_new_tuple
 #define sym_tuple_getitem _Py_uop_sym_tuple_getitem
 #define sym_tuple_length _Py_uop_sym_tuple_length
+#define sym_is_immortal _Py_uop_sym_is_immortal
 
 extern int
 optimize_to_bool(

Python/optimizer_symbols.c

@@ -493,6 +493,18 @@ _Py_uop_sym_tuple_length(JitOptSymbol *sym)
     return -1;
 }
 
+// Return true if known to be immortal.
+bool
+_Py_uop_sym_is_immortal(JitOptSymbol *sym)
+{
+    if (sym->tag == JIT_SYM_KNOWN_VALUE_TAG) {
+        return _Py_IsImmortal(sym->value.value);
+    }
+    if (sym->tag == JIT_SYM_KNOWN_CLASS_TAG) {
+        return sym->cls.type == &PyBool_Type;
+    }
+    return false;
+}
 
 // 0 on success, -1 on error.
 _Py_UOpsAbstractFrame *
@@ -675,6 +687,7 @@ _Py_uop_symbols_test(PyObject *Py_UNUSED(self), PyObject *Py_UNUSED(ignored))
     TEST_PREDICATE(_Py_uop_sym_is_const(sym), "42 is not a constant");
     TEST_PREDICATE(_Py_uop_sym_get_const(sym) != NULL, "42 as constant is NULL");
     TEST_PREDICATE(_Py_uop_sym_get_const(sym) == val_42, "42 as constant isn't 42");
+    TEST_PREDICATE(_Py_uop_sym_is_immortal(sym), "42 is not immortal");
 
     _Py_uop_sym_set_type(ctx, sym, &PyLong_Type);  // Should be a no-op
     TEST_PREDICATE(_Py_uop_sym_matches_type(sym, &PyLong_Type), "(42 and 42) isn't an int");
@@ -683,6 +696,9 @@ _Py_uop_symbols_test(PyObject *Py_UNUSED(self), PyObject *Py_UNUSED(ignored))
     _Py_uop_sym_set_type(ctx, sym, &PyFloat_Type);  // Should make it bottom
     TEST_PREDICATE(_Py_uop_sym_is_bottom(sym), "(42 and float) isn't bottom");
 
+    sym = _Py_uop_sym_new_type(ctx, &PyBool_Type);
+    TEST_PREDICATE(_Py_uop_sym_is_immortal(sym), "a bool is not immortal");
+
     sym = _Py_uop_sym_new_type(ctx, &PyLong_Type);
     if (sym == NULL) {
         goto fail;