clang: add support for asmjs arch and Emscripten OS

lib/CodeGen/CodeGenModule.cpp

Index: lib/CodeGen/CodeGenModule.cpp
diff --git a/lib/CodeGen/CodeGenModule.cpp b/lib/CodeGen/CodeGenModule.cpp
index b6f1f4c97c79134b33e7fa65ecb5715428f6e1e1..dea71c867fe4934c8d0e7a0dab485182304651f8 100644
--- a/lib/CodeGen/CodeGenModule.cpp
+++ b/lib/CodeGen/CodeGenModule.cpp
@@ -62,6 +62,7 @@ static CGCXXABI *createCXXABI(CodeGenModule &CGM) {
   switch (CGM.getTarget().getCXXABI().getKind()) {
   case TargetCXXABI::GenericAArch64:
   case TargetCXXABI::GenericARM:
+  case TargetCXXABI::Emscripten: // @LOCALMOD Emscripten
   case TargetCXXABI::iOS:
   case TargetCXXABI::iOS64:
   case TargetCXXABI::GenericItanium:
@@ -787,9 +788,13 @@ void CodeGenModule::SetLLVMFunctionAttributesForDefinition(const Decl *D,
   if (alignment)
     F->setAlignment(alignment);
 
-  // C++ ABI requires 2-byte alignment for member functions.
-  if (F->getAlignment() < 2 && isa<CXXMethodDecl>(D))
-    F->setAlignment(2);
+  // @LOCALMOD-START Emscripten
+  if (getTarget().getCXXABI().arePointersToMemberFunctionsAligned()) {
+    // C++ ABI requires 2-byte alignment for member functions.
+    if (F->getAlignment() < 2 && isa<CXXMethodDecl>(D))
+      F->setAlignment(2);
+  }
+  // @LOCALMOD-END Emscripten
 }
 
 void CodeGenModule::SetCommonAttributes(const Decl *D,