1 files changed, 18 insertions, 6 deletions
diff --git a/src/wasm-builder.h b/src/wasm-builder.h
index 69e7a7c6a..cc3b99138 100644
--- a/src/wasm-builder.h
+++ b/src/wasm-builder.h
@@ -664,20 +664,32 @@ public:
     ret->value = value;
     return ret;
   }
-  MemorySize* makeMemorySize(Name memoryName) {
-    auto memory = wasm.getMemory(memoryName);
+
+  // Some APIs can be told if the memory is 32 or 64-bit. If they are not
+  // informed of that, then the memory they refer to is looked up and that
+  // information fetched from there.
+  enum MemoryInfo { Memory32, Memory64, Unspecified };
+
+  bool isMemory64(Name memoryName, MemoryInfo info) {
+    return info == MemoryInfo::Memory64 || (info == MemoryInfo::Unspecified &&
+                                            wasm.getMemory(memoryName)->is64());
+  }
+
+  MemorySize* makeMemorySize(Name memoryName,
+                             MemoryInfo info = MemoryInfo::Unspecified) {
     auto* ret = wasm.allocator.alloc<MemorySize>();
-    if (memory->is64()) {
+    if (isMemory64(memoryName, info)) {
       ret->make64();
     }
     ret->memory = memoryName;
     ret->finalize();
     return ret;
   }
-  MemoryGrow* makeMemoryGrow(Expression* delta, Name memoryName) {
-    auto memory = wasm.getMemory(memoryName);
+  MemoryGrow* makeMemoryGrow(Expression* delta,
+                             Name memoryName,
+                             MemoryInfo info = MemoryInfo::Unspecified) {
     auto* ret = wasm.allocator.alloc<MemoryGrow>();
-    if (memory->is64()) {
+    if (isMemory64(memoryName, info)) {
       ret->make64();
     }
     ret->delta = delta;