Fuzzer: Generate both immutable and mutable globals (#5575)

1 files changed, 7 insertions, 3 deletions

diff --git a/src/tools/fuzzing/fuzzing.cpp b/src/tools/fuzzing/fuzzing.cpp
index 75eb3bd21..9beedc7fd 100644
--- a/src/tools/fuzzing/fuzzing.cpp
+++ b/src/tools/fuzzing/fuzzing.cpp
@@ -358,9 +358,13 @@ void TranslateToFuzzReader::setupGlobals() {
       type = getMVPType();
       init = makeConst(type);
     }
+    auto mutability = oneIn(2) ? Builder::Mutable : Builder::Immutable;
     auto global = builder.makeGlobal(
-      Names::getValidGlobalName(wasm, "global$"), type, init, Builder::Mutable);
+      Names::getValidGlobalName(wasm, "global$"), type, init, mutability);
     globalsByType[type].push_back(global->name);
+    if (mutability == Builder::Mutable) {
+      mutableGlobalsByType[type].push_back(global->name);
+    }
     wasm.addGlobal(std::move(global));
   }
 }
@@ -1489,8 +1493,8 @@ Expression* TranslateToFuzzReader::makeGlobalGet(Type type) {
 Expression* TranslateToFuzzReader::makeGlobalSet(Type type) {
   assert(type == Type::none);
   type = getConcreteType();
-  auto it = globalsByType.find(type);
-  if (it == globalsByType.end() || it->second.empty()) {
+  auto it = mutableGlobalsByType.find(type);
+  if (it == mutableGlobalsByType.end() || it->second.empty()) {
     return makeTrivial(Type::none);
   }
   auto name = pick(it->second);