check

book.tex

@@ -11839,24 +11839,30 @@ block40:
 
 As discussed earlier in this chapter, the garbage collector needs to
 access all the pointers in the root set, that is, all variables that
-are vectors. It will be the responsibility of the register allocator
+are tuple. It will be the responsibility of the register allocator
 to make sure that:
 \begin{enumerate}
-\item the root stack is used for spilling vector-typed variables, and
-\item if a vector-typed variable is live during a call to the
+\item the root stack is used for spilling tuple-typed variables, and
+\item if a tuple-typed variable is live during a call to the
   collector, it must be spilled to ensure it is visible to the
   collector.
 \end{enumerate}
 
 The later responsibility can be handled during construction of the
 interference graph, by adding interference edges between the call-live
-vector-typed variables and all the callee-saved registers. (They
-already interfere with the caller-saved registers.)  The type
-information for variables is in the \code{Program} form, so we
-recommend adding another parameter to the \code{build\_interference}
-function to communicate this alist.
+tuple-typed variables and all the callee-saved registers. (They
+already interfere with the caller-saved registers.)
+%
+\racket{The type information for variables is in the \code{Program}
+  form, so we recommend adding another parameter to the
+  \code{build\_interference} function to communicate this alist.}
+%
+\python{The type information for variables is generated by the type
+  checker for \LangCVec{}, stored a field named \code{var\_types} in
+  the \code{CProgram} AST mode. You'll need to propagate that
+  information so that it is available in this pass.}
 
-The spilling of vector-typed variables to the root stack can be
+The spilling of tuple-typed variables to the root stack can be
 handled after graph coloring, when choosing how to assign the colors
 (integers) to registers and stack locations. The \code{Program} output
 of this pass changes to also record the number of spills to the root