[clang][NFC] Use SmallString instead of SmallVector<char

Simplifies code in some places and is more explicit about what is being used.
No additional includes were added here so no impact on compile time.

clang/lib/AST/Interp/State.cpp

@@ -150,7 +150,7 @@ void State::addCallStack(unsigned Limit) {
       }
     }
 
-    SmallVector<char, 128> Buffer;
+    SmallString<128> Buffer;
     llvm::raw_svector_ostream Out(Buffer);
     F->describe(Out);
     addDiag(CallLocation, diag::note_constexpr_call_here) << Out.str();

clang/lib/AST/JSONNodeDumper.cpp

@@ -1418,7 +1418,7 @@ void JSONNodeDumper::VisitFixedPointLiteral(const FixedPointLiteral *FPL) {
   JOS.attribute("value", FPL->getValueAsString(/*Radix=*/10));
 }
 void JSONNodeDumper::VisitFloatingLiteral(const FloatingLiteral *FL) {
-  llvm::SmallVector<char, 16> Buffer;
+  llvm::SmallString<16> Buffer;
   FL->getValue().toString(Buffer);
   JOS.attribute("value", Buffer);
 }

clang/lib/Basic/Diagnostic.cpp

@@ -808,7 +808,7 @@ FormatDiagnostic(const char *DiagStr, const char *DiagEnd,
   /// QualTypeVals - Pass a vector of arrays so that QualType names can be
   /// compared to see if more information is needed to be printed.
   SmallVector<intptr_t, 2> QualTypeVals;
-  SmallVector<char, 64> Tree;
+  SmallString<64> Tree;
 
   for (unsigned i = 0, e = getNumArgs(); i < e; ++i)
     if (getArgKind(i) == DiagnosticsEngine::ak_qualtype)

clang/lib/CrossTU/CrossTranslationUnit.cpp

@@ -162,8 +162,7 @@ parseCrossTUIndex(StringRef IndexPath) {
       StringRef LookupName = LineRef.substr(0, Delimiter);
 
       // Store paths with posix-style directory separator.
-      SmallVector<char, 32> FilePath;
+      SmallString<32> FilePath(LineRef.substr(Delimiter + 1));
-      llvm::Twine{LineRef.substr(Delimiter + 1)}.toVector(FilePath);
       llvm::sys::path::native(FilePath, llvm::sys::path::Style::posix);
 
       bool InsertionOccured;
@@ -624,15 +623,14 @@ parseInvocationList(StringRef FileContent, llvm::sys::path::Style PathStyle) {
       return llvm::make_error<IndexError>(
           index_error_code::invocation_list_wrong_format);
 
-    SmallVector<char, 32> ValueStorage;
+    SmallString<32> ValueStorage;
     StringRef SourcePath = Key->getValue(ValueStorage);
 
     // Store paths with PathStyle directory separator.
-    SmallVector<char, 32> NativeSourcePath;
+    SmallString<32> NativeSourcePath(SourcePath);
-    llvm::Twine{SourcePath}.toVector(NativeSourcePath);
     llvm::sys::path::native(NativeSourcePath, PathStyle);
 
-    StringRef InvocationKey{NativeSourcePath.begin(), NativeSourcePath.size()};
+    StringRef InvocationKey(NativeSourcePath);
 
     if (InvocationList.find(InvocationKey) != InvocationList.end())
       return llvm::make_error<IndexError>(

clang/lib/Sema/Sema.cpp

@@ -1818,7 +1818,7 @@ bool Sema::findMacroSpelling(SourceLocation &locref, StringRef name) {
   loc = getSourceManager().getExpansionLoc(loc);
 
   // If that's written with the name, stop here.
-  SmallVector<char, 16> buffer;
+  SmallString<16> buffer;
   if (getPreprocessor().getSpelling(loc, buffer) == name) {
     locref = loc;
     return true;

clang/lib/Sema/SemaTemplateInstantiate.cpp

@@ -584,7 +584,7 @@ void Sema::PrintInstantiationStack() {
 
     case CodeSynthesisContext::DefaultTemplateArgumentInstantiation: {
       TemplateDecl *Template = cast<TemplateDecl>(Active->Template);
-      SmallVector<char, 128> TemplateArgsStr;
+      SmallString<128> TemplateArgsStr;
       llvm::raw_svector_ostream OS(TemplateArgsStr);
       Template->printName(OS);
       printTemplateArgumentList(OS, Active->template_arguments(),
@@ -650,7 +650,7 @@ void Sema::PrintInstantiationStack() {
       ParmVarDecl *Param = cast<ParmVarDecl>(Active->Entity);
       FunctionDecl *FD = cast<FunctionDecl>(Param->getDeclContext());
 
-      SmallVector<char, 128> TemplateArgsStr;
+      SmallString<128> TemplateArgsStr;
       llvm::raw_svector_ostream OS(TemplateArgsStr);
       FD->printName(OS);
       printTemplateArgumentList(OS, Active->template_arguments(),
@@ -802,7 +802,7 @@ void Sema::PrintInstantiationStack() {
         assert(isa<FunctionDecl>(Active->Entity));
         DiagID = diag::note_checking_constraints_for_function_here;
       }
-      SmallVector<char, 128> TemplateArgsStr;
+      SmallString<128> TemplateArgsStr;
       llvm::raw_svector_ostream OS(TemplateArgsStr);
       cast<NamedDecl>(Active->Entity)->printName(OS);
       if (!isa<FunctionDecl>(Active->Entity))

clang/lib/Serialization/ASTWriter.cpp

@@ -1622,7 +1622,7 @@ namespace {
     ASTWriter &Writer;
 
     // Keep track of the framework names we've used during serialization.
-    SmallVector<char, 128> FrameworkStringData;
+    SmallString<128> FrameworkStringData;
     llvm::StringMap<unsigned> FrameworkNameOffset;
 
   public:
@@ -1709,8 +1709,7 @@ namespace {
           = FrameworkNameOffset.find(Data.HFI.Framework);
         if (Pos == FrameworkNameOffset.end()) {
           Offset = FrameworkStringData.size() + 1;
-          FrameworkStringData.append(Data.HFI.Framework.begin(),
+          FrameworkStringData.append(Data.HFI.Framework);
-                                     Data.HFI.Framework.end());
           FrameworkStringData.push_back(0);
 
           FrameworkNameOffset[Data.HFI.Framework] = Offset;

clang/lib/Serialization/GlobalModuleIndex.cpp

@@ -905,7 +905,7 @@ GlobalModuleIndex::writeIndex(FileManager &FileMgr,
   }
 
   // The output buffer, into which the global index will be written.
-  SmallVector<char, 16> OutputBuffer;
+  SmallString<16> OutputBuffer;
   {
     llvm::BitstreamWriter OutputStream(OutputBuffer);
     if (Builder.writeIndex(OutputStream))
@@ -913,9 +913,8 @@ GlobalModuleIndex::writeIndex(FileManager &FileMgr,
                                      "failed writing index");
   }
 
-  return llvm::writeFileAtomically(
+  return llvm::writeFileAtomically((IndexPath + "-%%%%%%%%").str(), IndexPath,
-      (IndexPath + "-%%%%%%%%").str(), IndexPath,
+                                   OutputBuffer);
-      llvm::StringRef(OutputBuffer.data(), OutputBuffer.size()));
 }
 
 namespace {

clang/lib/StaticAnalyzer/Core/CheckerContext.cpp

@@ -93,7 +93,7 @@ StringRef CheckerContext::getMacroNameOrSpelling(SourceLocation &Loc) {
   if (Loc.isMacroID())
     return Lexer::getImmediateMacroName(Loc, getSourceManager(),
                                              getLangOpts());
-  SmallVector<char, 16> buf;
+  SmallString<16> buf;
   return Lexer::getSpelling(Loc, buf, getSourceManager(), getLangOpts());
 }
 

clang/lib/Tooling/Refactoring/Rename/USRFinder.cpp

@@ -133,13 +133,13 @@ const NamedDecl *getNamedDeclFor(const ASTContext &Context,
 }
 
 std::string getUSRForDecl(const Decl *Decl) {
-  llvm::SmallVector<char, 128> Buff;
+  llvm::SmallString<128> Buff;
 
   // FIXME: Add test for the nullptr case.
   if (Decl == nullptr || index::generateUSRForDecl(Decl, Buff))
     return "";
 
-  return std::string(Buff.data(), Buff.size());
+  return std::string(Buff);
 }
 
 } // end namespace tooling