[clang][StaticAnalyzer] Avoid 'raw_string_ostream::str' (NFC)

Since `raw_string_ostream` doesn't own the string buffer, it is
desirable (in terms of memory safety) for users to directly reference
the string buffer rather than use `raw_string_ostream::str()`.

Work towards TODO comment to remove `raw_string_ostream::str()`.

Author: JOE1994

clang/lib/StaticAnalyzer/Checkers/CheckObjCDealloc.cpp

@@ -247,8 +247,8 @@ void ObjCDeallocChecker::checkASTDecl(const ObjCImplementationDecl *D,
     PathDiagnosticLocation DLoc =
         PathDiagnosticLocation::createBegin(D, BR.getSourceManager());
 
-    BR.EmitBasicReport(D, this, Name, categories::CoreFoundationObjectiveC,
-                       OS.str(), DLoc);
+    BR.EmitBasicReport(D, this, Name, categories::CoreFoundationObjectiveC, Buf,
+                       DLoc);
     return;
   }
 }
@@ -585,7 +585,7 @@ void ObjCDeallocChecker::diagnoseMissingReleases(CheckerContext &C) const {
           " before '[super dealloc]'";
 
     auto BR = std::make_unique<PathSensitiveBugReport>(MissingReleaseBugType,
-                                                       OS.str(), ErrNode);
+                                                       Buf, ErrNode);
     C.emitReport(std::move(BR));
   }
 
@@ -706,8 +706,8 @@ bool ObjCDeallocChecker::diagnoseExtraRelease(SymbolRef ReleasedValue,
     OS <<  " property but was released in 'dealloc'";
   }
 
-  auto BR = std::make_unique<PathSensitiveBugReport>(ExtraReleaseBugType,
-                                                     OS.str(), ErrNode);
+  auto BR = std::make_unique<PathSensitiveBugReport>(ExtraReleaseBugType, Buf,
+                                                     ErrNode);
   BR->addRange(M.getOriginExpr()->getSourceRange());
 
   C.emitReport(std::move(BR));
@@ -749,7 +749,7 @@ bool ObjCDeallocChecker::diagnoseMistakenDealloc(SymbolRef DeallocedValue,
      << "' should be released rather than deallocated";
 
   auto BR = std::make_unique<PathSensitiveBugReport>(MistakenDeallocBugType,
-                                                     OS.str(), ErrNode);
+                                                     Buf, ErrNode);
   BR->addRange(M.getOriginExpr()->getSourceRange());
 
   C.emitReport(std::move(BR));

clang/lib/StaticAnalyzer/Checkers/RetainCountChecker/RetainCountDiagnostics.cpp

@@ -411,11 +411,11 @@ annotateConsumedSummaryMismatch(const ExplodedNode *N,
     }
   }
 
-  if (os.str().empty())
+  if (sbuf.empty())
     return nullptr;
 
   PathDiagnosticLocation L = PathDiagnosticLocation::create(CallExitLoc, SM);
-  return std::make_shared<PathDiagnosticEventPiece>(L, os.str());
+  return std::make_shared<PathDiagnosticEventPiece>(L, sbuf);
 }
 
 /// Annotate the parameter at the analysis entry point.
@@ -446,7 +446,7 @@ annotateStartParameter(const ExplodedNode *N, SymbolRef Sym,
     assert(CurrT->getCount() == 0);
     os << "0";
   }
-  return std::make_shared<PathDiagnosticEventPiece>(L, os.str());
+  return std::make_shared<PathDiagnosticEventPiece>(L, s);
 }
 
 PathDiagnosticPieceRef
@@ -493,7 +493,7 @@ RefCountReportVisitor::VisitNode(const ExplodedNode *N, BugReporterContext &BRC,
   if (PrevT && IsFreeUnowned && CurrV.isNotOwned() && PrevT->isOwned()) {
     os << "Object is now not exclusively owned";
     auto Pos = PathDiagnosticLocation::create(N->getLocation(), SM);
-    return std::make_shared<PathDiagnosticEventPiece>(Pos, os.str());
+    return std::make_shared<PathDiagnosticEventPiece>(Pos, sbuf);
   }
 
   // This is the allocation site since the previous node had no bindings
@@ -535,7 +535,7 @@ RefCountReportVisitor::VisitNode(const ExplodedNode *N, BugReporterContext &BRC,
     }
 
     PathDiagnosticLocation Pos(S, SM, N->getLocationContext());
-    return std::make_shared<PathDiagnosticEventPiece>(Pos, os.str());
+    return std::make_shared<PathDiagnosticEventPiece>(Pos, sbuf);
   }
 
   // Gather up the effects that were performed on the object at this
@@ -582,13 +582,13 @@ RefCountReportVisitor::VisitNode(const ExplodedNode *N, BugReporterContext &BRC,
   if (!shouldGenerateNote(os, PrevT, CurrV, DeallocSent))
     return nullptr;
 
-  if (os.str().empty())
+  if (sbuf.empty())
     return nullptr; // We have nothing to say!
 
   const Stmt *S = N->getLocation().castAs<StmtPoint>().getStmt();
   PathDiagnosticLocation Pos(S, BRC.getSourceManager(),
                                 N->getLocationContext());
-  auto P = std::make_shared<PathDiagnosticEventPiece>(Pos, os.str());
+  auto P = std::make_shared<PathDiagnosticEventPiece>(Pos, sbuf);
 
   // Add the range by scanning the children of the statement for any bindings
   // to Sym.
@@ -831,7 +831,7 @@ RefLeakReportVisitor::getEndPath(BugReporterContext &BRC,
        << RV->getCount();
   }
 
-  return std::make_shared<PathDiagnosticEventPiece>(L, os.str());
+  return std::make_shared<PathDiagnosticEventPiece>(L, sbuf);
 }
 
 RefCountReport::RefCountReport(const RefCountBug &D, const LangOptions &LOpts,

clang/lib/StaticAnalyzer/Core/ExprEngine.cpp

@@ -3900,7 +3900,7 @@ struct DOTGraphTraits<ExplodedGraph*> : public DefaultDOTGraphTraits {
     State->printDOT(Out, N->getLocationContext(), Space);
 
     Out << "\\l}\\l";
-    return Out.str();
+    return Buf;
   }
 };
 

clang/lib/StaticAnalyzer/Core/RangeConstraintManager.cpp

@@ -3283,7 +3283,7 @@ static std::string toString(const SymbolRef &Sym) {
   std::string S;
   llvm::raw_string_ostream O(S);
   Sym->dumpToStream(O);
-  return O.str();
+  return S;
 }
 
 void RangeConstraintManager::printConstraints(raw_ostream &Out,
@@ -3354,7 +3354,7 @@ static std::string toString(ProgramStateRef State, EquivalenceClass Class) {
     Out << "\"" << ClassMember << "\"";
   }
   Out << " ]";
-  return Out.str();
+  return Str;
 }
 
 void RangeConstraintManager::printEquivalenceClasses(raw_ostream &Out,

clang/lib/StaticAnalyzer/Core/SVals.cpp

@@ -271,7 +271,7 @@ void SVal::printJson(raw_ostream &Out, bool AddQuotes) const {
 
   dumpToStream(TempOut);
 
-  Out << JsonFormat(TempOut.str(), AddQuotes);
+  Out << JsonFormat(Buf, AddQuotes);
 }
 
 void SVal::dumpToStream(raw_ostream &os) const {