Avoid using LookupResult's implicit copy ctor and assignment operator to avoid warnings

[myatsina]

Summary

The purpose of this patch is to keep the same functionality without using LookupResult's implicit copy ctor and assignment operator, because they cause warnings when -Wdeprecated is passed.
This patch is meant to help the following review: http://reviews.llvm.org/D18123.

[rjmccall]

You can't call getFoundDecl() if !isSingleResult(). You should add a test case that actually tests the possibility that this lookup will fail.

[dblaikie]

Looks good - thanks!

[rjmccall]

Ignore Dave and fix the problem, please. :)

[myatsina]

How can I create a test case where isSingleResult() returns false?
I don't see existent tests in the commit that added this method's functionality.

[rjmccall]

Hmm. Checking whether LookupName returns false will catch a lot of simple cases. I think the test case you need might have to be a lookup that finds multiple overloads of a function in C++.

[myatsina]

Adding requested test case + changing the code accordingly

[rjmccall]

Thank you, LGTM.

lib/Sema/SemaStmtAsm.cpp

bool Sema::LookupInlineAsmField(StringRef Base, StringRef Member,
   SmallVector<StringRef, 2> Members;
   Member.split(Members, ".");
 
   LookupResult BaseResult(*this, &Context.Idents.get(Base), SourceLocation(),
                           LookupOrdinaryName);
 
   if (!LookupName(BaseResult, getCurScope()))
     return true;
   
-  LookupResult CurrBaseResult(BaseResult);
-
-  for (StringRef NextMember : Members) {
-
-    if (!CurrBaseResult.isSingleResult())
-      return true;
-
+  if(!BaseResult.isSingleResult())
+  NamedDecl *FoundDecl = BaseResult.getFoundDecl();
+  for (StringRef NextMember : Members) {
     const RecordType *RT = nullptr;
-    NamedDecl *FoundDecl = CurrBaseResult.getFoundDecl();
     if (VarDecl *VD = dyn_cast<VarDecl>(FoundDecl))
       RT = VD->getType()->getAs<RecordType>();
     else if (TypedefNameDecl *TD = dyn_cast<TypedefNameDecl>(FoundDecl)) {
       MarkAnyDeclReferenced(TD->getLocation(), TD, /*OdrUse=*/false);
       RT = TD->getUnderlyingType()->getAs<RecordType>();
     } else if (TypeDecl *TD = dyn_cast<TypeDecl>(FoundDecl))
       RT = TD->getTypeForDecl()->getAs<RecordType>();
     else if (FieldDecl *TD = dyn_cast<FieldDecl>(FoundDecl))
       RT = TD->getType()->getAs<RecordType>();
     if (!RT)
       return true;
 
     if (RequireCompleteType(AsmLoc, QualType(RT, 0),
                             diag::err_asm_incomplete_type))
       return true;
 
     LookupResult FieldResult(*this, &Context.Idents.get(NextMember),
                              SourceLocation(), LookupMemberName);
 
     if (!LookupQualifiedName(FieldResult, RT->getDecl()))
       return true;
 
+    if (!FieldResult.isSingleResult())
+      return true;
+    FoundDecl = FieldResult.getFoundDecl();
+
     // FIXME: Handle IndirectFieldDecl?
-    FieldDecl *FD = dyn_cast<FieldDecl>(FieldResult.getFoundDecl());
+    FieldDecl *FD = dyn_cast<FieldDecl>(FoundDecl);
     if (!FD)
       return true;
 
-    CurrBaseResult = FieldResult;
-
     const ASTRecordLayout &RL = Context.getASTRecordLayout(RT->getDecl());
     unsigned i = FD->getFieldIndex();
     CharUnits Result = Context.toCharUnitsFromBits(RL.getFieldOffset(i));
     Offset += (unsigned)Result.getQuantity();
   }
 
   return false;
 }

test/CodeGen/ms-inline-asm-errors.cpp

+// REQUIRES: x86-registered-target
+// RUN: %clang_cc1 -x c++ %s -triple i386-apple-darwin10 -std=c++11 -fasm-blocks -verify
+
+class A {
+public:
+  void foo(int a)   {}
+  void foo(float a) {}
+};
+
+
+void t_fail() {
+  __asm {
+    mov ecx, [eax]A.foo // expected-error {{Unable to lookup field reference!}}
+  }
+}