3 files changed, 31 insertions, 0 deletions
diff --git a/src/tools/wasm-emscripten-finalize.cpp b/src/tools/wasm-emscripten-finalize.cpp
index fd3d21df9..56a6c3b39 100644
--- a/src/tools/wasm-emscripten-finalize.cpp
+++ b/src/tools/wasm-emscripten-finalize.cpp
@@ -205,6 +205,7 @@ int main(int argc, const char* argv[]) {
     generator.generatePostInstantiateFunction();
   } else {
     generator.generateRuntimeFunctions();
+    generator.internalizeStackPointerGlobal();
     generator.generateMemoryGrowthFunction();
     // For side modules these gets called via __post_instantiate
     if (Function* F = generator.generateAssignGOTEntriesFunction()) {
diff --git a/src/wasm-emscripten.h b/src/wasm-emscripten.h
index 1f9b22926..0841708f2 100644
--- a/src/wasm-emscripten.h
+++ b/src/wasm-emscripten.h
@@ -44,6 +44,10 @@ public:
   // and restore functions.
   void replaceStackPointerGlobal();
 
+  // Remove the import of a mutable __stack_pointer and instead initialize the
+  // stack pointer from an immutable import.
+  void internalizeStackPointerGlobal();
+
   std::string
   generateEmscriptenMetadata(Address staticBump,
                              std::vector<Name> const& initializerFunctions);
diff --git a/src/wasm/wasm-emscripten.cpp b/src/wasm/wasm-emscripten.cpp
index 00a3eb6b7..8463354e8 100644
--- a/src/wasm/wasm-emscripten.cpp
+++ b/src/wasm/wasm-emscripten.cpp
@@ -397,6 +397,32 @@ private:
   Global* stackPointer;
 };
 
+// lld can sometimes produce a build with an imported mutable __stack_pointer
+// (i.e.  when linking with -fpie).  This method internalizes the
+// __stack_pointer and initializes it from an immutable global instead.
+// For -shared builds we instead call replaceStackPointerGlobal.
+void EmscriptenGlueGenerator::internalizeStackPointerGlobal() {
+  Global* stackPointer = getStackPointerGlobal();
+  if (!stackPointer || !stackPointer->imported() || !stackPointer->mutable_) {
+    return;
+  }
+
+  Name internalName = stackPointer->name;
+  Name externalName = internalName.c_str() + std::string("_import");
+
+  // Rename the imported global, and make it immutable
+  stackPointer->name = externalName;
+  stackPointer->mutable_ = false;
+  wasm.updateMaps();
+
+  // Create a new global with the old name that is not imported.
+  Builder builder(wasm);
+  auto* init = builder.makeGlobalGet(externalName, stackPointer->type);
+  auto* sp = builder.makeGlobal(
+    internalName, stackPointer->type, init, Builder::Mutable);
+  wasm.addGlobal(sp);
+}
+
 void EmscriptenGlueGenerator::replaceStackPointerGlobal() {
   Global* stackPointer = getStackPointerGlobal();
   if (!stackPointer) {