5 files changed, 29 insertions, 35 deletions
diff --git a/src/passes/DeadCodeElimination.cpp b/src/passes/DeadCodeElimination.cpp
index 9e2e194cb..4215de3f8 100644
--- a/src/passes/DeadCodeElimination.cpp
+++ b/src/passes/DeadCodeElimination.cpp
@@ -315,8 +315,10 @@ struct DeadCodeElimination
           DELEGATE(Drop);
         case Expression::Id::ReturnId:
           DELEGATE(Return);
-        case Expression::Id::HostId:
-          DELEGATE(Host);
+        case Expression::Id::MemorySizeId:
+          DELEGATE(MemorySize);
+        case Expression::Id::MemoryGrowId:
+          DELEGATE(MemoryGrow);
         case Expression::Id::NopId:
           DELEGATE(Nop);
         case Expression::Id::UnreachableId:
@@ -519,7 +521,11 @@ struct DeadCodeElimination
     blockifyReachableOperands({curr->value}, curr->type);
   }
 
-  void visitHost(Host* curr) { handleCall(curr); }
+  void visitMemorySize(MemorySize* curr) {}
+
+  void visitMemoryGrow(MemoryGrow* curr) {
+    blockifyReachableOperands({curr->delta}, curr->type);
+  }
 
   void visitFunction(Function* curr) { assert(reachableBreaks.size() == 0); }
 };
diff --git a/src/passes/MemoryPacking.cpp b/src/passes/MemoryPacking.cpp
index 1a1e87502..eac7fb7f0 100644
--- a/src/passes/MemoryPacking.cpp
+++ b/src/passes/MemoryPacking.cpp
@@ -77,9 +77,8 @@ const size_t DATA_DROP_SIZE = 3;
 namespace {
 
 Expression* makeShiftedMemorySize(Builder& builder) {
-  return builder.makeBinary(ShlInt32,
-                            builder.makeHost(MemorySize, Name(), {}),
-                            builder.makeConst(int32_t(16)));
+  return builder.makeBinary(
+    ShlInt32, builder.makeMemorySize(), builder.makeConst(int32_t(16)));
 }
 
 } // anonymous namespace
diff --git a/src/passes/Print.cpp b/src/passes/Print.cpp
index 15ab97098..916615e07 100644
--- a/src/passes/Print.cpp
+++ b/src/passes/Print.cpp
@@ -1430,16 +1430,8 @@ struct PrintExpressionContents
   }
   void visitDrop(Drop* curr) { printMedium(o, "drop"); }
   void visitReturn(Return* curr) { printMedium(o, "return"); }
-  void visitHost(Host* curr) {
-    switch (curr->op) {
-      case MemorySize:
-        printMedium(o, "memory.size");
-        break;
-      case MemoryGrow:
-        printMedium(o, "memory.grow");
-        break;
-    }
-  }
+  void visitMemorySize(MemorySize* curr) { printMedium(o, "memory.size"); }
+  void visitMemoryGrow(MemoryGrow* curr) { printMedium(o, "memory.grow"); }
   void visitRefNull(RefNull* curr) {
     printMedium(o, "ref.null ");
     o << curr->type.getHeapType();
@@ -1577,7 +1569,9 @@ struct PrintSExpression : public OverriddenVisitor<PrintSExpression> {
     o << ')';
   }
   void printFullLine(Expression* expression) {
-    !minify && doIndent(o, indent);
+    if (!minify) {
+      doIndent(o, indent);
+    }
     if (full) {
       o << "[" << expression->type << "] ";
     }
@@ -1945,20 +1939,17 @@ struct PrintSExpression : public OverriddenVisitor<PrintSExpression> {
     printFullLine(curr->value);
     decIndent();
   }
-  void visitHost(Host* curr) {
+  void visitMemorySize(MemorySize* curr) {
     o << '(';
     PrintExpressionContents(currFunction, o).visit(curr);
-    switch (curr->op) {
-      case MemoryGrow: {
-        incIndent();
-        printFullLine(curr->operands[0]);
-        decIndent();
-        break;
-      }
-      case MemorySize: {
-        o << ')';
-      }
-    }
+    o << ')';
+  }
+  void visitMemoryGrow(MemoryGrow* curr) {
+    o << '(';
+    PrintExpressionContents(currFunction, o).visit(curr);
+    incIndent();
+    printFullLine(curr->delta);
+    decIndent();
   }
   void visitRefNull(RefNull* curr) {
     o << '(';
diff --git a/src/passes/RemoveUnusedModuleElements.cpp b/src/passes/RemoveUnusedModuleElements.cpp
index 21cbc5e5b..3795022c2 100644
--- a/src/passes/RemoveUnusedModuleElements.cpp
+++ b/src/passes/RemoveUnusedModuleElements.cpp
@@ -111,11 +111,8 @@ struct ReachabilityAnalyzer : public PostWalker<ReachabilityAnalyzer> {
   void visitDataDrop(DataDrop* curr) { usesMemory = true; }
   void visitMemoryCopy(MemoryCopy* curr) { usesMemory = true; }
   void visitMemoryFill(MemoryFill* curr) { usesMemory = true; }
-  void visitHost(Host* curr) {
-    if (curr->op == MemorySize || curr->op == MemoryGrow) {
-      usesMemory = true;
-    }
-  }
+  void visitMemorySize(MemorySize* curr) { usesMemory = true; }
+  void visitMemoryGrow(MemoryGrow* curr) { usesMemory = true; }
   void visitRefFunc(RefFunc* curr) {
     if (reachable.count(
           ModuleElement(ModuleElementKind::Function, curr->func)) == 0) {
diff --git a/src/passes/Vacuum.cpp b/src/passes/Vacuum.cpp
index 94537619c..618a198e5 100644
--- a/src/passes/Vacuum.cpp
+++ b/src/passes/Vacuum.cpp
@@ -92,7 +92,8 @@ struct Vacuum : public WalkerPass<ExpressionStackWalker<Vacuum>> {
         case Expression::Id::StoreId:
         case Expression::Id::ReturnId:
         case Expression::Id::GlobalSetId:
-        case Expression::Id::HostId:
+        case Expression::Id::MemorySizeId:
+        case Expression::Id::MemoryGrowId:
         case Expression::Id::UnreachableId:
           return curr; // always needed