[WebAssembly] Use SetVector to stabilize iteration order after D120365

StringMap iteration order is not guaranteed to be deterministic
(https://llvm.org/docs/ProgrammersManual.html#llvm-adt-stringmap-h).

Author: MaskRay

llvm/include/llvm/CodeGen/MachineModuleInfoImpls.h

@@ -15,7 +15,7 @@
 #define LLVM_CODEGEN_MACHINEMODULEINFOIMPLS_H
 
 #include "llvm/ADT/DenseMap.h"
-#include "llvm/ADT/StringSet.h"
+#include "llvm/ADT/SetVector.h"
 #include "llvm/CodeGen/MachineModuleInfo.h"
 #include <cassert>
 
@@ -110,7 +110,7 @@ class MachineModuleInfoWasm : public MachineModuleInfoImpl {
 public:
   MachineModuleInfoWasm(const MachineModuleInfo &) {}
 
-  StringSet<> MachineSymbolsUsed;
+  SetVector<StringRef> MachineSymbolsUsed;
 };
 
 } // end namespace llvm

llvm/lib/Target/WebAssembly/WebAssemblyAsmPrinter.cpp

@@ -303,8 +303,8 @@ void WebAssemblyAsmPrinter::emitDecls(const Module &M) {
   // only find symbols that have been used. Unused symbols from globals will
   // not be found here.
   MachineModuleInfoWasm &MMIW = MMI->getObjFileInfo<MachineModuleInfoWasm>();
-  for (const auto &Name : MMIW.MachineSymbolsUsed) {
-    auto *WasmSym = cast<MCSymbolWasm>(getOrCreateWasmSymbol(Name.getKey()));
+  for (StringRef Name : MMIW.MachineSymbolsUsed) {
+    auto *WasmSym = cast<MCSymbolWasm>(getOrCreateWasmSymbol(Name));
     if (WasmSym->isFunction()) {
       // TODO(wvo): is there any case where this overlaps with the call to
       // emitFunctionType in the loop below?

llvm/test/CodeGen/WebAssembly/functype-emission.ll

@@ -3,8 +3,8 @@
 ; Demonstrates that appropriate .functype directives are emitted for defined
 ; functions, declared functions, and any libcalls.
 
-; CHECK: .functype __unordtf2 (i64, i64, i64, i64) -> (i32)
 ; CHECK: .functype __multi3 (i32, i64, i64, i64, i64) -> ()
+; CHECK: .functype __unordtf2 (i64, i64, i64, i64) -> (i32)
 ; CHECK: .functype defined_fun_1 (f64) -> (i64)
 ; CHECK: .functype defined_fun_2 (f64, i32) -> (i64)
 ; CHECK: .functype declared_fun (i32, f32, i64) -> (i32)