4 files changed, 52 insertions, 13 deletions

diff --git a/src/passes/RemoveUnusedModuleElements.cpp b/src/passes/RemoveUnusedModuleElements.cpp
index 05e80af0d..6cd050da9 100644
--- a/src/passes/RemoveUnusedModuleElements.cpp
+++ b/src/passes/RemoveUnusedModuleElements.cpp
@@ -153,6 +153,10 @@ struct FunctionTypeAnalyzer : public PostWalker<FunctionTypeAnalyzer> {
 };
 
 struct RemoveUnusedModuleElements : public Pass {
+  bool rootAllFunctions;
+
+  RemoveUnusedModuleElements(bool rootAllFunctions) : rootAllFunctions(rootAllFunctions) {}
+
   void run(PassRunner* runner, Module* module) override {
     optimizeGlobalsAndFunctions(module);
     optimizeFunctionTypes(module);
@@ -170,6 +174,12 @@ struct RemoveUnusedModuleElements : public Pass {
         roots.emplace_back(ModuleElementKind::Function, module->start);
       }
     }
+    // If told to, root all the functions
+    if (rootAllFunctions) {
+      for (auto& func : module->functions) {
+        roots.emplace_back(ModuleElementKind::Function, func->name);
+      }
+    }
     // Exports are roots.
     bool exportsMemory = false;
     bool exportsTable = false;
@@ -184,6 +194,16 @@ struct RemoveUnusedModuleElements : public Pass {
         exportsTable = true;
       }
     }
+    // Check for special imports are roots.
+    bool importsMemory = false;
+    bool importsTable = false;
+    for (auto& curr : module->imports) {
+      if (curr->kind == ExternalKind::Memory) {
+        importsMemory = true;
+      } else if (curr->kind == ExternalKind::Table) {
+        importsTable = true;
+      }
+    }
     // For now, all functions that can be called indirectly are marked as roots.
     for (auto& segment : module->table.segments) {
       for (auto& curr : segment.data) {
@@ -218,19 +238,31 @@ struct RemoveUnusedModuleElements : public Pass {
     }
     module->updateMaps();
     // Handle the memory and table
-    if (!exportsMemory && !analyzer.usesMemory && module->memory.segments.empty()) {
-      module->memory.exists = false;
-      module->memory.imported = false;
-      module->memory.initial = 0;
-      module->memory.max = 0;
-      removeImport(ExternalKind::Memory, module);
+    if (!exportsMemory && !analyzer.usesMemory) {
+      if (!importsMemory) {
+        // The memory is unobservable to the outside, we can remove the contents.
+        module->memory.segments.clear();
+      }
+      if (module->memory.segments.empty()) {
+        module->memory.exists = false;
+        module->memory.imported = false;
+        module->memory.initial = 0;
+        module->memory.max = 0;
+        removeImport(ExternalKind::Memory, module);
+      }
     }
-    if (!exportsTable && !analyzer.usesTable && module->table.segments.empty()) {
-      module->table.exists = false;
-      module->table.imported = false;
-      module->table.initial = 0;
-      module->table.max = 0;
-      removeImport(ExternalKind::Table, module);
+    if (!exportsTable && !analyzer.usesTable) {
+      if (!importsTable) {
+        // The table is unobservable to the outside, we can remove the contents.
+        module->table.segments.clear();
+      }
+      if (module->table.segments.empty()) {
+        module->table.exists = false;
+        module->table.imported = false;
+        module->table.initial = 0;
+        module->table.max = 0;
+        removeImport(ExternalKind::Table, module);
+      }
     }
   }
 
@@ -279,7 +311,11 @@ struct RemoveUnusedModuleElements : public Pass {
 };
 
 Pass* createRemoveUnusedModuleElementsPass() {
-  return new RemoveUnusedModuleElements();
+  return new RemoveUnusedModuleElements(false);
+}
+
+Pass* createRemoveUnusedNonFunctionModuleElementsPass() {
+  return new RemoveUnusedModuleElements(true);
 }
 
 } // namespace wasm
diff --git a/src/passes/pass.cpp b/src/passes/pass.cpp
index ae9484d29..2d93d99ae 100644
--- a/src/passes/pass.cpp
+++ b/src/passes/pass.cpp
@@ -103,6 +103,7 @@ void PassRegistry::registerPasses() {
   registerPass("remove-memory", "removes memory segments", createRemoveMemoryPass);
   registerPass("remove-unused-brs", "removes breaks from locations that are not needed", createRemoveUnusedBrsPass);
   registerPass("remove-unused-module-elements", "removes unused module elements", createRemoveUnusedModuleElementsPass);
+  registerPass("remove-unused-nonfunction-module-elements", "removes unused module elements that are not functions", createRemoveUnusedNonFunctionModuleElementsPass);
   registerPass("remove-unused-names", "removes names from locations that are never branched to", createRemoveUnusedNamesPass);
   registerPass("reorder-functions", "sorts functions by access frequency", createReorderFunctionsPass);
   registerPass("reorder-locals", "sorts locals by access frequency", createReorderLocalsPass);
diff --git a/src/passes/passes.h b/src/passes/passes.h
index 5ab03a439..cf77f9fac 100644
--- a/src/passes/passes.h
+++ b/src/passes/passes.h
@@ -60,6 +60,7 @@ Pass* createRemoveImportsPass();
 Pass* createRemoveMemoryPass();
 Pass* createRemoveUnusedBrsPass();
 Pass* createRemoveUnusedModuleElementsPass();
+Pass* createRemoveUnusedNonFunctionModuleElementsPass();
 Pass* createRemoveUnusedNamesPass();
 Pass* createReorderFunctionsPass();
 Pass* createReorderLocalsPass();
diff --git a/src/tools/wasm-reduce.cpp b/src/tools/wasm-reduce.cpp
index 6b8d93f97..7b7ff9da3 100644
--- a/src/tools/wasm-reduce.cpp
+++ b/src/tools/wasm-reduce.cpp
@@ -249,6 +249,7 @@ struct Reducer : public WalkerPass<PostWalker<Reducer, UnifiedExpressionVisitor<
       "--remove-memory",
       "--remove-unused-names --remove-unused-brs",
       "--remove-unused-module-elements",
+      "--remove-unused-nonfunction-module-elements",
       "--reorder-functions",
       "--reorder-locals",
       "--simplify-locals --vacuum",