add .generic_base to bases in AST so compiler doesn't need to do it

Author: iritkatriel

Include/internal/pycore_compile.h

@@ -136,7 +136,6 @@ int _PyCompile_IsNestedScope(struct _PyCompiler *c);
 int _PyCompile_IsInInlinedComp(struct _PyCompiler *c);
 int _PyCompile_ScopeType(struct _PyCompiler *c);
 int _PyCompile_OptimizationLevel(struct _PyCompiler *c);
-PyArena *_PyCompile_Arena(struct _PyCompiler *c);
 int _PyCompile_LookupArg(struct _PyCompiler *c, PyCodeObject *co, PyObject *name);
 PyObject *_PyCompile_Qualname(struct _PyCompiler *c);
 _PyCompile_CodeUnitMetadata *_PyCompile_Metadata(struct _PyCompiler *c);

Parser/action_helpers.c

@@ -758,6 +758,30 @@ _PyPegen_class_def(expr_ty a, arguments_ty b, asdl_stmt_seq *c, asdl_type_param_
     asdl_stmt_seq *body = c;
     asdl_expr_seq *decorator_list = NULL;
     asdl_type_param_seq *type_params = t;
+
+    int is_generic = asdl_seq_LEN(type_params) > 0;
+    if (is_generic) {
+        /* Add */
+        asdl_expr_seq *orig_bases = bases;
+        Py_ssize_t orig_len = asdl_seq_LEN(orig_bases);
+        bases = _Py_asdl_expr_seq_new(orig_len + 1, arena);
+        if (bases == NULL) {
+            return NULL;
+        }
+        for (Py_ssize_t i = 0; i < orig_len; i++) {
+            asdl_seq_SET(bases, i, asdl_seq_GET(orig_bases, i));
+        }
+        _Py_DECLARE_STR(generic_base, ".generic_base");
+        expr_ty name_node = _PyAST_Name(
+            &_Py_STR(generic_base), Load,
+            lineno, col_offset, end_lineno, end_col_offset, arena
+        );
+        if (name_node == NULL) {
+            return NULL;
+        }
+        asdl_seq_SET(bases, orig_len, name_node);
+    }
+
     return _PyAST_ClassDef(name, bases, keywords, body, decorator_list, type_params,
                            lineno, col_offset, end_lineno, end_col_offset, arena);
 }

Python/codegen.c

@@ -76,7 +76,6 @@ typedef struct _PyCompiler compiler;
 #define SCOPE_TYPE(C) _PyCompile_ScopeType(C)
 #define QUALNAME(C) _PyCompile_Qualname(C)
 #define METADATA(C) _PyCompile_Metadata(C)
-#define ARENA(C) _PyCompile_Arena(C)
 
 typedef _PyInstruction instruction;
 typedef _PyInstructionSequence instr_sequence;
@@ -1549,27 +1548,8 @@ codegen_class(compiler *c, stmt_ty s)
         ADDOP_I_IN_SCOPE(c, loc, CALL_INTRINSIC_1, INTRINSIC_SUBSCRIPT_GENERIC);
         RETURN_IF_ERROR_IN_SCOPE(c, codegen_nameop(c, loc, &_Py_STR(generic_base), Store));
 
-        Py_ssize_t original_len = asdl_seq_LEN(s->v.ClassDef.bases);
-        asdl_expr_seq *bases = _Py_asdl_expr_seq_new(
-            original_len + 1, ARENA(c));
-        if (bases == NULL) {
-            _PyCompile_ExitScope(c);
-            return ERROR;
-        }
-        for (Py_ssize_t i = 0; i < original_len; i++) {
-            asdl_seq_SET(bases, i, asdl_seq_GET(s->v.ClassDef.bases, i));
-        }
-        expr_ty name_node = _PyAST_Name(
-            &_Py_STR(generic_base), Load,
-            loc.lineno, loc.col_offset, loc.end_lineno, loc.end_col_offset, ARENA(c)
-        );
-        if (name_node == NULL) {
-            _PyCompile_ExitScope(c);
-            return ERROR;
-        }
-        asdl_seq_SET(bases, original_len, name_node);
         RETURN_IF_ERROR_IN_SCOPE(c, codegen_call_helper(c, loc, 2,
-                                                        bases,
+                                                        s->v.ClassDef.bases,
                                                         s->v.ClassDef.keywords));
 
         PyCodeObject *co = _PyCompile_OptimizeAndAssemble(c, 0);

Python/compile.c

@@ -1244,12 +1244,6 @@ _PyCompile_Metadata(compiler *c)
     return &c->u->u_metadata;
 }
 
-PyArena *
-_PyCompile_Arena(compiler *c)
-{
-    return c->c_arena;
-}
-
 #ifndef NDEBUG
 int
 _PyCompile_IsTopLevelAwait(compiler *c)