[refactor] Add for and while to the new frontend AST builder (#3353)

* add static group for

* format

* add range for

* fix import

* add ndrange for

* add grouped ndrange for

* add grouped struct for

* format

* add break, continue and pass

* format

* add while

* add test

python/taichi/lang/ast_builder_utils.py

@@ -1,4 +1,5 @@
 import ast
+from enum import Enum
 
 from taichi.lang.exception import TaichiSyntaxError
 
@@ -91,7 +92,7 @@ def check_loop_var(self, loop_var):
                 .format(loop_var))
 
 
-class IRScopeGuard:
+class VariableScopeGuard:
     def __init__(self, scopes, stmt_block=None):
         self.scopes = scopes
         self.stmt_block = stmt_block
@@ -104,6 +105,29 @@ def __exit__(self, exc_type, exc_val, exc_tb):
         self.scopes.pop()
 
 
+class LoopStatus(Enum):
+    Normal = 0
+    Break = 1
+    Continue = 2
+
+
+class ControlScopeAttribute:
+    def __init__(self):
+        self.is_static = False
+        self.status = LoopStatus.Normal
+
+
+class ControlScopeGuard:
+    def __init__(self, scopes):
+        self.scopes = scopes
+
+    def __enter__(self):
+        self.scopes.append(ControlScopeAttribute())
+
+    def __exit__(self, exc_type, exc_val, exc_tb):
+        self.scopes.pop()
+
+
 class IRBuilderContext:
     def __init__(self,
                  excluded_parameters=(),
@@ -125,18 +149,34 @@ def __init__(self,
 
     # e.g.: FunctionDef, Module, Global
     def variable_scope_guard(self, *args):
-        return IRScopeGuard(self.local_scopes, *args)
+        return VariableScopeGuard(self.local_scopes, *args)
 
     # e.g.: For, While
     def control_scope_guard(self):
-        return ScopeGuard(self.control_scopes)
+        return ControlScopeGuard(self.control_scopes)
 
     def current_scope(self):
         return self.local_scopes[-1]
 
     def current_control_scope(self):
         return self.control_scopes[-1]
 
+    def loop_status(self):
+        if len(self.control_scopes):
+            return self.control_scopes[-1].status
+        return LoopStatus.Normal
+
+    def set_loop_status(self, status):
+        self.control_scopes[-1].status = status
+
+    def set_static_loop(self):
+        self.control_scopes[-1].is_static = True
+
+    def is_in_static(self):
+        if len(self.control_scopes):
+            return self.control_scopes[-1].is_static
+        return False
+
     def is_var_declared(self, name):
         for s in self.local_scopes:
             if name in s: