bpo-43693: Compute deref offsets in compiler (gh-25152)

Merges locals and cells into a single array.
Saves a pointer in the interpreter and means that we don't need the LOAD_CLOSURE opcode any more

https://bugs.python.org/issue43693

1 files changed, 23 insertions, 6 deletions

diff --git a/Doc/library/dis.rst b/Doc/library/dis.rst
index eaa001c..bc206f7 100644
--- a/Doc/library/dis.rst
+++ b/Doc/library/dis.rst
@@ -1058,16 +1058,24 @@ All of the following opcodes use their arguments.
 
 .. opcode:: LOAD_CLOSURE (i)
 
-   Pushes a reference to the cell contained in slot *i* of the cell and free
-   variable storage.  The name of the variable is
-   ``co_fastlocalnames[i + len(co_varnames)]``.
+   Pushes a reference to the cell contained in slot ``i`` of the "fast locals"
+   storage.  The name of the variable is ``co_fastlocalnames[i]``.
+
+   Note that ``LOAD_CLOSURE`` is effectively an alias for ``LOAD_FAST``.
+   It exists to keep bytecode a little more readable.
+
+   .. versionchanged:: 3.11
+      ``i`` is no longer offset by the length of ``co_varnames``.
 
 
 .. opcode:: LOAD_DEREF (i)
 
-   Loads the cell contained in slot *i* of the cell and free variable storage.
+   Loads the cell contained in slot ``i`` of the "fast locals" storage.
    Pushes a reference to the object the cell contains on the stack.
 
+   .. versionchanged:: 3.11
+      ``i`` is no longer offset by the length of ``co_varnames``.
+
 
 .. opcode:: LOAD_CLASSDEREF (i)
 
@@ -1077,20 +1085,29 @@ All of the following opcodes use their arguments.
 
    .. versionadded:: 3.4
 
+   .. versionchanged:: 3.11
+      ``i`` is no longer offset by the length of ``co_varnames``.
+
 
 .. opcode:: STORE_DEREF (i)
 
-   Stores TOS into the cell contained in slot *i* of the cell and free variable
+   Stores TOS into the cell contained in slot ``i`` of the "fast locals"
    storage.
 
+   .. versionchanged:: 3.11
+      ``i`` is no longer offset by the length of ``co_varnames``.
+
 
 .. opcode:: DELETE_DEREF (i)
 
-   Empties the cell contained in slot *i* of the cell and free variable storage.
+   Empties the cell contained in slot ``i`` of the "fast locals" storage.
    Used by the :keyword:`del` statement.
 
    .. versionadded:: 3.2
 
+   .. versionchanged:: 3.11
+      ``i`` is no longer offset by the length of ``co_varnames``.
+
 
 .. opcode:: RAISE_VARARGS (argc)