From e46b80278760574ea126c2359d17fa8d344d0ccd Mon Sep 17 00:00:00 2001
From: Thomas Lively <tlively@google.com>
Date: Mon, 12 Jan 2026 18:54:25 -0800
Subject: [PATCH 1/2] Do not recollect types in ReorderTypes

ReorderTypes previously collected the module types and their counts,
even though it already extends GlobalTypeRewriter, which also collects
the module types in its constructor. Not only did this duplicate work,
it was also a subtle source of bugs because ReorderTypes and
GlobalTypeRewriter collected types slightly differently. ReorderTypes
collected the binary types and GlobalTypeRewriter collected the used IR
types. This could result in different types being collected for the same
multivalue control flow signatures, causing an assertion failure when
a type was seemingly missing from the collected info.

Fix the problem and make the pass more efficient by simply not
collecting the types two separate times.
---
 src/passes/ReorderTypes.cpp        | 12 +++---------
 test/lit/passes/reorder-types.wast | 25 +++++++++++++++++++++++++
 2 files changed, 28 insertions(+), 9 deletions(-)

diff --git a/src/passes/ReorderTypes.cpp b/src/passes/ReorderTypes.cpp
index d2ac65127a8..4a8e7593c5f 100644
--- a/src/passes/ReorderTypes.cpp
+++ b/src/passes/ReorderTypes.cpp
@@ -33,8 +33,6 @@ namespace {
 struct ReorderingTypeRewriter : GlobalTypeRewriter {
   using InfoMap = InsertOrderedMap<HeapType, ModuleUtils::HeapTypeInfo>;
 
-  InfoMap& typeInfo;
-
   // Use a simpler cost calculation so the effects can be seen with smaller test
   // cases.
   bool forTesting;
@@ -45,8 +43,8 @@ struct ReorderingTypeRewriter : GlobalTypeRewriter {
   static constexpr float maxFactor = 1.0;
   static constexpr Index numFactors = 21;
 
-  ReorderingTypeRewriter(Module& wasm, InfoMap& typeInfo, bool forTesting)
-    : GlobalTypeRewriter(wasm), typeInfo(typeInfo), forTesting(forTesting) {}
+  ReorderingTypeRewriter(Module& wasm, bool forTesting)
+    : GlobalTypeRewriter(wasm), forTesting(forTesting) {}
 
   std::vector<HeapType> getSortedTypes(PredecessorGraph preds) override {
     auto numTypes = preds.size();
@@ -150,11 +148,7 @@ struct ReorderTypes : Pass {
       Fatal() << "ReorderTypes requires --closed-world";
     }
 
-    // Collect the use counts for each type.
-    auto typeInfo = ModuleUtils::collectHeapTypeInfo(
-      *module, ModuleUtils::TypeInclusion::BinaryTypes);
-
-    ReorderingTypeRewriter(*module, typeInfo, forTesting).update();
+    ReorderingTypeRewriter(*module, forTesting).update();
   }
 };
 
diff --git a/test/lit/passes/reorder-types.wast b/test/lit/passes/reorder-types.wast
index f4c5be93281..c5b8a13ef9e 100644
--- a/test/lit/passes/reorder-types.wast
+++ b/test/lit/passes/reorder-types.wast
@@ -391,3 +391,28 @@
     (local (ref $Y))
   )
 )
+
+(module
+  ;; Regression test. ReorderTypes used to collect the types used in the binary
+  ;; for their counts, which in this case includes $multi because it is part of
+  ;; the rec group. However, GlobalTypeRewriter separately collected only the
+  ;; used IR types, which includes a standalone function type instead of $multi.
+  ;; The sort then tried to lookup the count for the standalone function type
+  ;; and crashed when it couldn't find it.
+  (rec
+    (type $multi (func (result (ref $A) (ref $B))))
+    ;; CHECK:      (rec
+    ;; CHECK-NEXT:  (type $A (sub (struct)))
+    (type $A (sub (struct)))
+    ;; CHECK:       (type $B (sub $A (struct)))
+    (type $B (sub $A (struct)))
+  )
+  ;; CHECK:      (func $test (type $3) (param $0 i32) (result (ref $A) (ref $B))
+  ;; CHECK-NEXT:  (unreachable)
+  ;; CHECK-NEXT: )
+  (func $test (param i32) (result (ref $A) (ref $B))
+    (block (type $multi) (result (ref $A) (ref $B))
+      (unreachable)
+    )
+  )
+)

From 04937d42b08d0cc09b1220d3c9cd8942ef101bf8 Mon Sep 17 00:00:00 2001
From: Thomas Lively <tlively@google.com>
Date: Tue, 13 Jan 2026 17:36:40 -0800
Subject: [PATCH 2/2] remove unnecessary using

---
 src/passes/ReorderTypes.cpp | 2 --
 1 file changed, 2 deletions(-)

diff --git a/src/passes/ReorderTypes.cpp b/src/passes/ReorderTypes.cpp
index 4a8e7593c5f..e120822da51 100644
--- a/src/passes/ReorderTypes.cpp
+++ b/src/passes/ReorderTypes.cpp
@@ -31,8 +31,6 @@ namespace wasm {
 namespace {
 
 struct ReorderingTypeRewriter : GlobalTypeRewriter {
-  using InfoMap = InsertOrderedMap<HeapType, ModuleUtils::HeapTypeInfo>;
-
   // Use a simpler cost calculation so the effects can be seen with smaller test
   // cases.
   bool forTesting;