From 62cc5fc6462da1a4bbcd6cce06e49e1a04d4c258 Mon Sep 17 00:00:00 2001
From: Jim Blandy <jimb@red-bean.com>
Date: Thu, 14 Oct 2021 21:44:28 -0700
Subject: [PATCH] [msl-out] Delete Writer::runtime_sized_buffers. (#1462)

This is just a table mapping handles to their indices, but we can just fetch the
index directly from the handle. We never iterate over its entries, but even if
we did, we could at least use a HashSet instead of a HashMap.
---
 src/back/msl/writer.rs | 7 +------
 1 file changed, 1 insertion(+), 6 deletions(-)

diff --git a/src/back/msl/writer.rs b/src/back/msl/writer.rs
index e743dc5f66..e35bee19b8 100644
--- a/src/back/msl/writer.rs
+++ b/src/back/msl/writer.rs
@@ -307,7 +307,6 @@ pub struct Writer<W> {
     names: FastHashMap<NameKey, String>,
     named_expressions: crate::NamedExpressions,
     namer: proc::Namer,
-    runtime_sized_buffers: FastHashMap<Handle<crate::GlobalVariable>, usize>,
     #[cfg(test)]
     put_expression_stack_pointers: FastHashSet<*const ()>,
     #[cfg(test)]
@@ -473,7 +472,6 @@ impl<W: Write> Writer<W> {
             names: FastHashMap::default(),
             named_expressions: crate::NamedExpressions::default(),
             namer: proc::Namer::default(),
-            runtime_sized_buffers: FastHashMap::default(),
             #[cfg(test)]
             put_expression_stack_pointers: Default::default(),
             #[cfg(test)]
@@ -707,11 +705,10 @@ impl<W: Write> Writer<W> {
                     _ => return Err(Error::Validation),
                 };
 
-                let buffer_idx = self.runtime_sized_buffers[&handle];
                 write!(
                     self.out,
                     "(1 + (_buffer_sizes.size{idx} - {offset} - {span}) / {stride})",
-                    idx = buffer_idx,
+                    idx = handle.index(),
                     offset = offset,
                     span = span,
                     stride = stride,
@@ -1761,7 +1758,6 @@ impl<W: Write> Writer<W> {
         self.names.clear();
         self.namer
             .reset(module, super::keywords::RESERVED, &[], &mut self.names);
-        self.runtime_sized_buffers.clear();
         self.struct_member_pads.clear();
 
         writeln!(
@@ -1778,7 +1774,6 @@ impl<W: Write> Writer<W> {
             for (handle, var) in module.global_variables.iter() {
                 if needs_array_length(var.ty, &module.types) {
                     let idx = handle.index();
-                    self.runtime_sized_buffers.insert(handle, idx);
                     indices.push(idx);
                 }
             }