[dynamo] Enforce some invariants on ConstantVariable.create (pytorch#140984)

This addresses pytorch#140745 (comment).

Pull Request resolved: pytorch#140984
Approved by: https://github.com/jansel
ghstack dependencies: pytorch#141504

Author: StrongerXi

torch/_dynamo/variables/base.py

@@ -7,6 +7,7 @@
 from .. import variables
 from ..current_scope_id import current_scope_id
 from ..exc import unimplemented
+from ..guards import GuardBuilder, install_guard
 from ..source import AttrSource, Source
 from ..utils import istype
 
@@ -328,6 +329,8 @@ def var_getattr(self, tx: "InstructionTranslator", name: str) -> "VariableTracke
         if not variables.ConstantVariable.is_literal(value):
             raise NotImplementedError
         source = self.source and AttrSource(self.source, name)
+        if source:
+            install_guard(source.make_guard(GuardBuilder.CONSTANT_MATCH))
         return variables.ConstantVariable.create(value, source=source)
 
     def is_proxy(self):

torch/_dynamo/variables/constant.py

@@ -8,7 +8,6 @@
 
 from .. import variables
 from ..exc import unimplemented, UserError, UserErrorType
-from ..guards import GuardBuilder, install_guard
 from ..utils import common_constant_types, istype, np
 from .base import typestr, VariableTracker
 
@@ -24,6 +23,9 @@ def create(value, **kwargs) -> VariableTracker:
         Create a `ConstantVariable` based on the given value, and supports
         automatic routing for collection types like `tuple` (in which case we'd
         create `ConstantVariable` for the leaf items).
+
+        NOTE: the caller must install the proper guards if needed; most often
+        the guard will be `CONSTANT_MATCH`.
         """
         source = kwargs.get("source", None)
 
@@ -38,8 +40,6 @@ def create(value, **kwargs) -> VariableTracker:
             items = []
             for i, x in enumerate(value):
                 item_source = GetItemSource(source, i) if source else None
-                if item_source:
-                    install_guard(item_source.make_guard(GuardBuilder.CONSTANT_MATCH))
                 items.append(
                     ConstantVariable.create(
                         x,

torch/_dynamo/variables/misc.py

@@ -145,8 +145,7 @@ def var_getattr(self, tx: "InstructionTranslator", name: str) -> "VariableTracke
             return GetAttrVariable(self, name)
         if source:
             install_guard(source.make_guard(GuardBuilder.CONSTANT_MATCH))
-            return variables.ConstantVariable.create(value, source=source)
-        return variables.ConstantVariable.create(value)
+        return variables.ConstantVariable.create(value, source=source)
 
     def call_method(
         self,