[WebAssembly] Fix import statement

[binji]

Summary

Imports should be generated like (param i32 f32...) not (param i32) (param f32) ...

[jfb]

lib/Target/WebAssembly/WebAssemblyAsmPrinter.cpp

357

Does this do the right thing when the param list is empty? IIUC it does:

(param)

?

Could you add a test?

[jfb]

lgtm

[jfb]

r251714

lib/Target/WebAssembly/WebAssemblyAsmPrinter.cpp

 }
 
 void WebAssemblyAsmPrinter::EmitEndOfAsmFile(Module &M) {
-    SmallString<128> Str;
-    raw_svector_ostream OS(Str);
   for (const Function &F : M)
     if (F.isDeclarationForLinker()) {
       assert(F.hasName() && "imported functions must have a name");
       if (F.getName().startswith("llvm."))
         continue;
       if (Str.empty())
         OS << "\t.imports\n";
       Type *Rt = F.getReturnType();
-      OS << "\t.import " <<  toSymbol(F.getName()) << " \"\" \"" << F.getName()
+      OS << "\t.import " << toSymbol(F.getName()) << " \"\" \"" << F.getName()
          << "\"";
+      OS << " (param";
       for (const Argument &A : F.args())
-       OS << " (param " << toString(A.getType()) << ')';
+        OS << ' ' << toString(A.getType());
+      OS << ')';
       if (!Rt->isVoidTy())
         OS << " (result " << toString(Rt) << ')';
       OS << '\n';
     }
   OutStreamer->EmitRawText(OS.str());
 }
 

test/CodeGen/WebAssembly/import.ll

 ; CHECK-LABEL: .imports
 ; CHECK-NEXT:  .import $printi "" "printi" (param i32) (result i32)
 ; CHECK-NEXT:  .import $printf "" "printf" (param f32) (result f32)
-; CHECK-NEXT:  .import $printv "" "printv"
+; CHECK-NEXT:  .import $printv "" "printv" (param)
+; CHECK-NEXT:  .import $add2 "" "add2" (param i32 i32) (result i32)
 declare i32 @printi(i32)
 declare float @printf(float)
 declare void @printv()
+declare i32 @add2(i32, i32)