[clang] Use nullptr instead of 0 or NULL (NFC)

Identified with modernize-use-nullptr.

clang/lib/AST/ASTContext.cpp

@@ -8476,8 +8476,8 @@ static TypedefDecl *CreateHexagonBuiltinVaListDecl(const ASTContext *Context) {
     FieldDecl *Field = FieldDecl::Create(
         const_cast<ASTContext &>(*Context), VaListTagDecl, SourceLocation(),
         SourceLocation(), &Context->Idents.get(FieldNames[i]), FieldTypes[i],
-        /*TInfo=*/0,
-        /*BitWidth=*/0,
+        /*TInfo=*/nullptr,
+        /*BitWidth=*/nullptr,
         /*Mutable=*/false, ICIS_NoInit);
     Field->setAccess(AS_public);
     VaListTagDecl->addDecl(Field);

clang/lib/AST/Type.cpp

@@ -194,7 +194,7 @@ void ConstantArrayType::Profile(llvm::FoldingSetNodeID &ID,
   ID.AddInteger(ArraySize.getZExtValue());
   ID.AddInteger(SizeMod);
   ID.AddInteger(TypeQuals);
-  ID.AddBoolean(SizeExpr != 0);
+  ID.AddBoolean(SizeExpr != nullptr);
   if (SizeExpr)
     SizeExpr->Profile(ID, Context, true);
 }

clang/lib/CodeGen/CodeGenFunction.cpp

@@ -1595,9 +1595,9 @@ void CodeGenFunction::EmitBranchToCounterBlock(
   if (!InstrumentRegions || !isInstrumentedCondition(Cond))
     return EmitBranchOnBoolExpr(Cond, TrueBlock, FalseBlock, TrueCount, LH);
 
-  llvm::BasicBlock *ThenBlock = NULL;
-  llvm::BasicBlock *ElseBlock = NULL;
-  llvm::BasicBlock *NextBlock = NULL;
+  llvm::BasicBlock *ThenBlock = nullptr;
+  llvm::BasicBlock *ElseBlock = nullptr;
+  llvm::BasicBlock *NextBlock = nullptr;
 
   // Create the block we'll use to increment the appropriate counter.
   llvm::BasicBlock *CounterIncrBlock = createBasicBlock("lop.rhscnt");

clang/lib/CodeGen/TargetInfo.cpp

@@ -8693,7 +8693,7 @@ Address HexagonABIInfo::EmitVAArgForHexagonLinux(CodeGenFunction &CGF,
                             llvm::ConstantInt::get(CGF.Int32Ty, ArgSize),
                             "__new_saved_reg_area_pointer");
 
-  llvm::Value *UsingStack = 0;
+  llvm::Value *UsingStack = nullptr;
   UsingStack = CGF.Builder.CreateICmpSGT(__new_saved_reg_area_pointer,
                                          __saved_reg_area_end_pointer);
 

clang/lib/Driver/Driver.cpp

@@ -437,7 +437,7 @@ DerivedArgList *Driver::TranslateInputArgs(const InputArgList &Args) const {
 
   // Enforce -static if -miamcu is present.
   if (Args.hasFlag(options::OPT_miamcu, options::OPT_mno_iamcu, false))
-    DAL->AddFlagArg(0, Opts.getOption(options::OPT_static));
+    DAL->AddFlagArg(nullptr, Opts.getOption(options::OPT_static));
 
 // Add a default value of -mlinker-version=, if one was given and the user
 // didn't specify one.

clang/lib/Driver/ToolChains/WebAssembly.cpp

@@ -76,7 +76,7 @@ void wasm::Linker::ConstructJob(Compilation &C, const JobAction &JA,
   ToolChain.AddFilePathLibArgs(Args, CmdArgs);
 
   const char *Crt1 = "crt1.o";
-  const char *Entry = NULL;
+  const char *Entry = nullptr;
 
   // If crt1-command.o exists, it supports new-style commands, so use it.
   // Otherwise, use the old crt1.o. This is a temporary transition measure.

clang/lib/Interpreter/IncrementalParser.cpp

@@ -256,7 +256,7 @@ IncrementalParser::Parse(llvm::StringRef input) {
                                /*LoadedOffset=*/0, NewLoc);
 
   // NewLoc only used for diags.
-  if (PP.EnterSourceFile(FID, /*DirLookup=*/0, NewLoc))
+  if (PP.EnterSourceFile(FID, /*DirLookup=*/nullptr, NewLoc))
     return llvm::make_error<llvm::StringError>("Parsing failed. "
                                                "Cannot enter source file.",
                                                std::error_code());

clang/lib/Lex/Lexer.cpp

@@ -2548,9 +2548,9 @@ static bool isEndOfBlockCommentWithEscapedNewLine(const char *CurPtr,
   assert(CurPtr[0] == '\n' || CurPtr[0] == '\r');
 
   // Position of the first trigraph in the ending sequence.
-  const char *TrigraphPos = 0;
+  const char *TrigraphPos = nullptr;
   // Position of the first whitespace after a '\' in the ending sequence.
-  const char *SpacePos = 0;
+  const char *SpacePos = nullptr;
 
   while (true) {
     // Back up off the newline.

clang/lib/StaticAnalyzer/Core/BugReporterVisitors.cpp

@@ -2804,7 +2804,8 @@ bool ConditionBRVisitor::patternMatch(const Expr *Ex,
       Out << '\''
           << Lexer::getSourceText(
                  CharSourceRange::getTokenRange(Ex->getSourceRange()),
-                 BRC.getSourceManager(), BRC.getASTContext().getLangOpts(), 0)
+                 BRC.getSourceManager(), BRC.getASTContext().getLangOpts(),
+                 nullptr)
           << '\'';
   }
 

clang/tools/libclang/CIndex.cpp

@@ -4949,7 +4949,7 @@ CXStringSet *clang_Cursor_getObjCManglings(CXCursor C) {
 
 CXPrintingPolicy clang_getCursorPrintingPolicy(CXCursor C) {
   if (clang_Cursor_isNull(C))
-    return 0;
+    return nullptr;
   return new PrintingPolicy(getCursorContext(C).getPrintingPolicy());
 }
 
@@ -6975,16 +6975,16 @@ CXToken *clang_getToken(CXTranslationUnit TU, CXSourceLocation Location) {
 
   if (isNotUsableTU(TU)) {
     LOG_BAD_TU(TU);
-    return NULL;
+    return nullptr;
   }
 
   ASTUnit *CXXUnit = cxtu::getASTUnit(TU);
   if (!CXXUnit)
-    return NULL;
+    return nullptr;
 
   SourceLocation Begin = cxloc::translateSourceLocation(Location);
   if (Begin.isInvalid())
-    return NULL;
+    return nullptr;
   SourceManager &SM = CXXUnit->getSourceManager();
   std::pair<FileID, unsigned> DecomposedEnd = SM.getDecomposedLoc(Begin);
   DecomposedEnd.second +=
@@ -6997,7 +6997,7 @@ CXToken *clang_getToken(CXTranslationUnit TU, CXSourceLocation Location) {
   getTokens(CXXUnit, SourceRange(Begin, End), CXTokens);
 
   if (CXTokens.empty())
-    return NULL;
+    return nullptr;
 
   CXTokens.resize(1);
   CXToken *Token = static_cast<CXToken *>(llvm::safe_malloc(sizeof(CXToken)));