4 files changed, 26 insertions, 20 deletions

diff --git a/src/asm2wasm.h b/src/asm2wasm.h
index d958c4b6a..c193791f8 100644
--- a/src/asm2wasm.h
+++ b/src/asm2wasm.h
@@ -426,13 +426,16 @@ public:
   std::map<IString, MappedGlobal> mappedGlobals;
 
 private:
-  void allocateGlobal(IString name, Type type) {
+  void allocateGlobal(IString name, Type type, Literal value=Literal()) {
     assert(mappedGlobals.find(name) == mappedGlobals.end());
+    if (value.type == none) {
+      value = Literal::makeZero(type);
+    }
     mappedGlobals.emplace(name, MappedGlobal(type));
     wasm.addGlobal(builder.makeGlobal(
       name,
       type,
-      LiteralUtils::makeZero(type, wasm),
+      builder.makeConst(value),
       Builder::Mutable
     ));
   }
@@ -986,8 +989,7 @@ void Asm2WasmBuilder::processAsm(Ref ast) {
         Ref value = pair[1];
         if (value->isNumber()) {
           // global int
-          assert(value->getNumber() == 0);
-          allocateGlobal(name, Type::i32);
+          allocateGlobal(name, Type::i32, Literal(int32_t(value->getInteger())));
         } else if (value[0] == BINARY) {
           // int import
           assert(value[1] == OR && value[3]->isNumber() && value[3]->getNumber() == 0);
diff --git a/src/tools/wasm-emscripten-finalize.cpp b/src/tools/wasm-emscripten-finalize.cpp
index 3d74138cc..3ea3629c5 100644
--- a/src/tools/wasm-emscripten-finalize.cpp
+++ b/src/tools/wasm-emscripten-finalize.cpp
@@ -36,6 +36,8 @@ using namespace cashew;
 using namespace wasm;
 
 int main(int argc, const char *argv[]) {
+  const uint64_t INVALID_BASE = -1;
+
   std::string infile;
   std::string outfile;
   std::string inputSourceMapFilename;
@@ -46,7 +48,8 @@ int main(int argc, const char *argv[]) {
   bool debugInfo = false;
   bool legalizeJavaScriptFFI = true;
   unsigned numReservedFunctionPointers = 0;
-  uint64_t globalBase;
+  uint64_t globalBase = INVALID_BASE;
+  uint64_t initialStackPointer = INVALID_BASE;
   Options options("wasm-emscripten-finalize",
                   "Performs Emscripten-specific transforms on .wasm files");
   options
@@ -75,11 +78,16 @@ int main(int argc, const char *argv[]) {
                                           const std::string &argument) {
              numReservedFunctionPointers = std::stoi(argument);
            })
-      .add("--global-base", "", "Where lld started to place globals",
+      .add("--global-base", "", "The address at which static globals were placed",
            Options::Arguments::One,
            [&globalBase](Options*, const std::string&argument ) {
              globalBase = std::stoull(argument);
            })
+      .add("--initial-stack-pointer", "", "The initial location of the stack pointer",
+           Options::Arguments::One,
+           [&initialStackPointer](Options*, const std::string&argument ) {
+             initialStackPointer = std::stoull(argument);
+           })
 
       .add("--input-source-map", "-ism", "Consume source map from the specified file",
            Options::Arguments::One,
@@ -141,6 +149,12 @@ int main(int argc, const char *argv[]) {
   uint32_t dataSize = 0;
 
   if (!isSideModule) {
+    if (globalBase == INVALID_BASE) {
+      Fatal() << "globalBase must be set";
+    }
+    if (initialStackPointer == INVALID_BASE) {
+      Fatal() << "initialStackPointer must be set";
+    }
     Export* dataEndExport = wasm.getExport("__data_end");
     if (dataEndExport == nullptr) {
       Fatal() << "__data_end export not found";
@@ -189,7 +203,7 @@ int main(int argc, const char *argv[]) {
   } else {
     generator.generateRuntimeFunctions();
     generator.generateMemoryGrowthFunction();
-    generator.generateStackInitialization();
+    generator.generateStackInitialization(initialStackPointer);
     // emscripten calls this by default for side libraries so we only need
     // to include in as a static ctor for main module case.
     if (wasm.getExportOrNull("__post_instantiate")) {
diff --git a/src/wasm-emscripten.h b/src/wasm-emscripten.h
index 2b626a7c9..d078cafbf 100644
--- a/src/wasm-emscripten.h
+++ b/src/wasm-emscripten.h
@@ -36,7 +36,7 @@ public:
 
   void generateRuntimeFunctions();
   Function* generateMemoryGrowthFunction();
-  void generateStackInitialization();
+  void generateStackInitialization(Address addr);
 
   // Create thunks for use with emscripten Runtime.dynCall. Creates one for each
   // signature in the indirect function table.
diff --git a/src/wasm/wasm-emscripten.cpp b/src/wasm/wasm-emscripten.cpp
index b18fe0c76..88e66ea07 100644
--- a/src/wasm/wasm-emscripten.cpp
+++ b/src/wasm/wasm-emscripten.cpp
@@ -156,19 +156,9 @@ Function* EmscriptenGlueGenerator::generateMemoryGrowthFunction() {
   return growFunction;
 }
 
-void EmscriptenGlueGenerator::generateStackInitialization() {
-  // Replace a global with a constant initial value with an imported
-  // initial value, which emscripten JS will send us.
-  // TODO: with mutable imported globals, we can avoid adding another
-  //       global for the import.
-  Builder builder(wasm);
-  auto* import = builder.makeGlobal(STACK_INIT, i32, nullptr, Builder::Immutable);
-  import->module = ENV;
-  import->base = STACKTOP;
-  wasm.addGlobal(import);
+void EmscriptenGlueGenerator::generateStackInitialization(Address addr) {
   auto* stackPointer = getStackPointerGlobal();
-  assert(stackPointer->init->is<Const>());
-  stackPointer->init = builder.makeGetGlobal(import->name, i32);
+  stackPointer->init->cast<Const>()->value = Literal(int32_t(addr));
 }
 
 static bool hasI64ResultOrParam(FunctionType* ft) {