8 files changed, 18 insertions, 2 deletions
diff --git a/src/passes/MergeBlocks.cpp b/src/passes/MergeBlocks.cpp
index 578d4fc45..5033d4016 100644
--- a/src/passes/MergeBlocks.cpp
+++ b/src/passes/MergeBlocks.cpp
@@ -24,6 +24,8 @@
 namespace wasm {
 
 struct MergeBlocks : public WalkerPass<PostWalker<MergeBlocks>> {
+  bool isFunctionParallel() { return true; }
+
   void visitBlock(Block *curr) {
     bool more = true;
     while (more) {
diff --git a/src/passes/OptimizeInstructions.cpp b/src/passes/OptimizeInstructions.cpp
index ca79468f5..28cac726a 100644
--- a/src/passes/OptimizeInstructions.cpp
+++ b/src/passes/OptimizeInstructions.cpp
@@ -26,6 +26,8 @@
 namespace wasm {
 
 struct OptimizeInstructions : public WalkerPass<PostWalker<OptimizeInstructions>> {
+  bool isFunctionParallel() { return true; }
+
   void visitIf(If* curr) {
     // flip branches to get rid of an i32.eqz
     if (curr->ifFalse) {
diff --git a/src/passes/PostEmscripten.cpp b/src/passes/PostEmscripten.cpp
index effbad30a..ef01b11fe 100644
--- a/src/passes/PostEmscripten.cpp
+++ b/src/passes/PostEmscripten.cpp
@@ -25,6 +25,8 @@
 namespace wasm {
 
 struct PostEmscripten : public WalkerPass<PostWalker<PostEmscripten>> {
+  bool isFunctionParallel() { return true; }
+
   // When we have a Load from a local value (typically a GetLocal) plus a constant offset,
   // we may be able to fold it in.
   // The semantics of the Add are to wrap, while wasm offset semantics purposefully do
diff --git a/src/passes/RemoveUnusedBrs.cpp b/src/passes/RemoveUnusedBrs.cpp
index 41db36d2c..6718fc14b 100644
--- a/src/passes/RemoveUnusedBrs.cpp
+++ b/src/passes/RemoveUnusedBrs.cpp
@@ -24,6 +24,8 @@
 namespace wasm {
 
 struct RemoveUnusedBrs : public WalkerPass<PostWalker<RemoveUnusedBrs>> {
+  bool isFunctionParallel() { return true; }
+
   // preparation: try to unify branches, as the fewer there are, the higher a chance we can remove them
   // specifically for if-else, turn an if-else with branches to the same target at the end of each
   // child, and with a value, to a branch to that target containing the if-else
diff --git a/src/passes/RemoveUnusedNames.cpp b/src/passes/RemoveUnusedNames.cpp
index 71569eefb..d33b5081a 100644
--- a/src/passes/RemoveUnusedNames.cpp
+++ b/src/passes/RemoveUnusedNames.cpp
@@ -24,6 +24,8 @@
 namespace wasm {
 
 struct RemoveUnusedNames : public WalkerPass<PostWalker<RemoveUnusedNames>> {
+  bool isFunctionParallel() { return true; }
+
   // We maintain a list of branches that we saw in children, then when we reach
   // a parent block, we know if it was branched to
   std::set<Name> branchesSeen;
diff --git a/src/passes/ReorderLocals.cpp b/src/passes/ReorderLocals.cpp
index ca046773b..66ea131de 100644
--- a/src/passes/ReorderLocals.cpp
+++ b/src/passes/ReorderLocals.cpp
@@ -27,6 +27,7 @@
 namespace wasm {
 
 struct ReorderLocals : public WalkerPass<PostWalker<ReorderLocals>> {
+  bool isFunctionParallel() { return true; }
 
   std::map<Name, uint32_t> counts;
 
diff --git a/src/passes/SimplifyLocals.cpp b/src/passes/SimplifyLocals.cpp
index 408fea7ab..6220d0780 100644
--- a/src/passes/SimplifyLocals.cpp
+++ b/src/passes/SimplifyLocals.cpp
@@ -33,6 +33,8 @@
 namespace wasm {
 
 struct SimplifyLocals : public WalkerPass<LinearExecutionWalker<SimplifyLocals>> {
+  bool isFunctionParallel() { return true; }
+
   struct SinkableInfo {
     Expression** item;
     EffectAnalyzer effects;
@@ -157,7 +159,7 @@ struct SimplifyLocals : public WalkerPass<LinearExecutionWalker<SimplifyLocals>>
     self->pushTask(visitPre, currp);
   }
 
-  void startWalk(Function *func) {
+  void walk(Expression*& root) {
     // multiple passes may be required per function, consider this:
     //    x = load
     //    y = store
@@ -166,7 +168,7 @@ struct SimplifyLocals : public WalkerPass<LinearExecutionWalker<SimplifyLocals>>
     do {
       sunk = false;
       // main operation
-      walk(func->body);
+      WalkerPass<LinearExecutionWalker<SimplifyLocals>>::walk(root);
       // after optimizing a function, we can see if we have set_locals
       // for a local with no remaining gets, in which case, we can
       // remove the set.
@@ -192,6 +194,7 @@ struct SimplifyLocals : public WalkerPass<LinearExecutionWalker<SimplifyLocals>>
       // clean up
       numGetLocals.clear();
       setLocalOrigins.clear();
+      sinkables.clear();
     } while (sunk);
   }
 };
diff --git a/src/passes/Vacuum.cpp b/src/passes/Vacuum.cpp
index ef83958c4..060dcd9dc 100644
--- a/src/passes/Vacuum.cpp
+++ b/src/passes/Vacuum.cpp
@@ -24,6 +24,8 @@
 namespace wasm {
 
 struct Vacuum : public WalkerPass<PostWalker<Vacuum>> {
+  bool isFunctionParallel() { return true; }
+
   void visitBlock(Block *curr) {
     // compress out nops
     int skip = 0;