[clang] Strip unneeded calls to raw_string_ostream::str() (NFC)

Avoid extra layer of indirection.

p.s.
Also, remove calls to raw_string_ostream::flush(), which are no-ops.

Author: JOE1994

clang/tools/clang-refactor/ClangRefactor.cpp

@@ -560,7 +560,6 @@ class ClangRefactorTool {
          << "' can't be invoked with the given arguments:\n";
       for (const auto &Opt : MissingOptions)
         OS << "  missing '-" << Opt.getKey() << "' option\n";
-      OS.flush();
       return llvm::make_error<llvm::StringError>(
           Error, llvm::inconvertibleErrorCode());
     }
@@ -591,7 +590,6 @@ class ClangRefactorTool {
       OS << "note: the following actions are supported:\n";
       for (const auto &Subcommand : SubCommands)
         OS.indent(2) << Subcommand->getName() << "\n";
-      OS.flush();
       return llvm::make_error<llvm::StringError>(
           Error, llvm::inconvertibleErrorCode());
     }

clang/tools/driver/cc1gen_reproducer_main.cpp

@@ -105,8 +105,8 @@ static std::string generateReproducerMetaInfo(const ClangInvocationInfo &Info) {
   OS << '}';
   // FIXME: Compare unsaved file hashes and report mismatch in the reproducer.
   if (Info.Dump)
-    llvm::outs() << "REPRODUCER METAINFO: " << OS.str() << "\n";
-  return std::move(OS.str());
+    llvm::outs() << "REPRODUCER METAINFO: " << Result << "\n";
+  return Result;
 }
 
 /// Generates a reproducer for a set of arguments from a specific invocation.

clang/unittests/AST/SourceLocationTest.cpp

@@ -105,7 +105,7 @@ class WhileParenLocationVerifier : public MatchVerifier<WhileStmt> {
       RParenLoc.print(Msg, *Result.SourceManager);
       Msg << ">";
 
-      this->setFailure(Msg.str());
+      this->setFailure(MsgStr);
     }
   }
 };

clang/unittests/AST/TemplateNameTest.cpp

@@ -21,7 +21,7 @@ std::string printTemplateName(TemplateName TN, const PrintingPolicy &Policy,
   std::string Result;
   llvm::raw_string_ostream Out(Result);
   TN.print(Out, Policy, Qual);
-  return Out.str();
+  return Result;
 }
 
 TEST(TemplateName, PrintTemplate) {

clang/unittests/Analysis/ExprMutationAnalyzerTest.cpp

@@ -78,7 +78,7 @@ mutatedBy(const SmallVectorImpl<BoundNodes> &Results, ASTUnit *AST) {
     std::string Buffer;
     llvm::raw_string_ostream Stream(Buffer);
     By->printPretty(Stream, nullptr, AST->getASTContext().getPrintingPolicy());
-    Chain.emplace_back(StringRef(Stream.str()).trim().str());
+    Chain.emplace_back(StringRef(Buffer).trim().str());
     E = dyn_cast<DeclRefExpr>(By);
   }
   return Chain;

clang/unittests/Frontend/OutputStreamTest.cpp

@@ -67,7 +67,7 @@ TEST(FrontendOutputTests, TestVerboseOutputStreamShared) {
 
   bool Success = ExecuteCompilerInvocation(&Compiler);
   EXPECT_FALSE(Success);
-  EXPECT_TRUE(!VerboseStream.str().empty());
+  EXPECT_TRUE(!VerboseBuffer.empty());
   EXPECT_TRUE(StringRef(VerboseBuffer.data()).contains("errors generated"));
 }
 

clang/unittests/StaticAnalyzer/RangeSetTest.cpp

@@ -25,7 +25,7 @@ template <class RangeOrSet> static std::string toString(const RangeOrSet &Obj) {
   std::string ObjRepresentation;
   llvm::raw_string_ostream SS(ObjRepresentation);
   Obj.dump(SS);
-  return SS.str();
+  return ObjRepresentation;
 }
 LLVM_ATTRIBUTE_UNUSED static std::string toString(const llvm::APSInt &Point) {
   return toString(Point, 10);

clang/unittests/Tooling/ASTSelectionTest.cpp

@@ -171,7 +171,7 @@ TEST(ASTSelectionFinder, CursorAtStartOfFunction) {
         std::string DumpValue;
         llvm::raw_string_ostream OS(DumpValue);
         Node->Children[0].dump(OS);
-        ASSERT_EQ(OS.str(), "FunctionDecl \"f\" contains-selection\n");
+        ASSERT_EQ(DumpValue, "FunctionDecl \"f\" contains-selection\n");
       });
 }
 

clang/unittests/Tooling/DiagnosticsYamlTest.cpp

@@ -151,7 +151,7 @@ TEST(DiagnosticsYamlTest, serializesDiagnostics) {
   yaml::Output YAML(YamlContentStream);
   YAML << TUD;
 
-  EXPECT_EQ(YAMLContent, YamlContentStream.str());
+  EXPECT_EQ(YAMLContent, YamlContent);
 }
 
 TEST(DiagnosticsYamlTest, deserializesDiagnostics) {

clang/unittests/Tooling/RecursiveASTVisitorTestDeclVisitor.cpp

@@ -67,7 +67,7 @@ class NamedDeclVisitor
     Decl->getNameForDiagnostic(OS,
                                Decl->getASTContext().getPrintingPolicy(),
                                true);
-    Match(OS.str(), Decl->getLocation());
+    Match(NameWithTemplateArgs, Decl->getLocation());
     return true;
   }
 };