Document stack effect APIs.

Author: ZeroIntensity

Doc/c-api/veryhigh.rst

@@ -396,3 +396,40 @@ Available start symbols
       * :pep:`484`
 
    .. versionadded:: 3.8
+
+
+Stack Effects
+^^^^^^^^^^^^^
+
+.. seealso::
+   :py:func:`dis.stack_effect`
+
+
+.. c:macro:: PY_INVALID_STACK_EFFECT
+
+   Sentinel value representing an invalid stack effect.
+
+   This is currently equivalent to ``INT_MAX``.
+
+   .. versionadded:: 3.8
+
+
+.. c:function:: int PyCompile_OpcodeStackEffect(int opcode, int oparg)
+
+   Compute the stack effect of *opcode* with argument *oparg*.
+
+   On success, this function returns the stack effect; on failure, this
+   returns :c:macro:`PY_INVALID_STACK_EFFECT`.
+
+   .. versionadded:: 3.4
+
+
+.. c:function:: int PyCompile_OpcodeStackEffectWithJump(int opcode, int oparg)
+
+   Similar to :c:func:`PyCompile_OpcodeStackEffect`, but also includes the
+   stack effect of jumping.
+
+   On success, this function returns the stack effect; on failure, this
+   returns :c:macro:`PY_INVALID_STACK_EFFECT`.
+
+   .. versionadded:: 3.8