Allow the preprocessor to be constructed without performing target-
and language-specific initialization. Use this to allow ASTUnit to
create a preprocessor object *before* loading the AST file. No actual
functionality change.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@138983 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Basic/Builtins.cpp b/lib/Basic/Builtins.cpp
index 57b771a..7bdcdc6 100644
--- a/lib/Basic/Builtins.cpp
+++ b/lib/Basic/Builtins.cpp
@@ -32,11 +32,15 @@
   return TSRecords[ID - Builtin::FirstTSBuiltin];
 }
 
-Builtin::Context::Context(const TargetInfo &Target) {
+Builtin::Context::Context() {
   // Get the target specific builtins from the target.
   TSRecords = 0;
   NumTSRecords = 0;
-  Target.getTargetBuiltins(TSRecords, NumTSRecords);
+}
+
+void Builtin::Context::InitializeTarget(const TargetInfo &Target) {
+  assert(NumTSRecords == 0 && "Already initialized target?");
+  Target.getTargetBuiltins(TSRecords, NumTSRecords);  
 }
 
 /// InitializeBuiltins - Mark the identifiers for all the builtins with their
diff --git a/lib/Frontend/ASTUnit.cpp b/lib/Frontend/ASTUnit.cpp
index b09c435..370e1a9 100644
--- a/lib/Frontend/ASTUnit.cpp
+++ b/lib/Frontend/ASTUnit.cpp
@@ -376,28 +376,51 @@
 /// \brief Gathers information from ASTReader that will be used to initialize
 /// a Preprocessor.
 class ASTInfoCollector : public ASTReaderListener {
+  Preprocessor &PP;
   LangOptions &LangOpt;
   HeaderSearch &HSI;
-  std::string &TargetTriple;
+  llvm::IntrusiveRefCntPtr<TargetInfo> &Target;
   std::string &Predefines;
   unsigned &Counter;
 
   unsigned NumHeaderInfos;
 
+  bool InitializedPreprocessor;
 public:
-  ASTInfoCollector(LangOptions &LangOpt, HeaderSearch &HSI,
-                   std::string &TargetTriple, std::string &Predefines,
+  ASTInfoCollector(Preprocessor &PP,
+                   LangOptions &LangOpt, HeaderSearch &HSI,
+                   llvm::IntrusiveRefCntPtr<TargetInfo> &Target,
+                   std::string &Predefines,
                    unsigned &Counter)
-    : LangOpt(LangOpt), HSI(HSI), TargetTriple(TargetTriple),
-      Predefines(Predefines), Counter(Counter), NumHeaderInfos(0) {}
+    : PP(PP), LangOpt(LangOpt), HSI(HSI), Target(Target),
+      Predefines(Predefines), Counter(Counter), NumHeaderInfos(0),
+      InitializedPreprocessor(false) {}
 
   virtual bool ReadLanguageOptions(const LangOptions &LangOpts) {
+    if (InitializedPreprocessor)
+      return false;
+    
     LangOpt = LangOpts;
+    
+    // Initialize the preprocessor.
+    PP.Initialize(*Target);
+    InitializedPreprocessor = true;
     return false;
   }
 
   virtual bool ReadTargetTriple(StringRef Triple) {
-    TargetTriple = Triple;
+    // If we've already initialized the target, don't do it again.
+    if (Target)
+      return false;
+    
+    // FIXME: This is broken, we should store the TargetOptions in the AST file.
+    TargetOptions TargetOpts;
+    TargetOpts.ABI = "";
+    TargetOpts.CXXABI = "";
+    TargetOpts.CPU = "";
+    TargetOpts.Features.clear();
+    TargetOpts.Triple = Triple;
+    Target = TargetInfo::CreateTargetInfo(PP.getDiagnostics(), TargetOpts);
     return false;
   }
 
@@ -573,12 +596,18 @@
   // Gather Info for preprocessor construction later on.
 
   HeaderSearch &HeaderInfo = *AST->HeaderInfo.get();
-  std::string TargetTriple;
   std::string Predefines;
   unsigned Counter;
 
   llvm::OwningPtr<ASTReader> Reader;
 
+  AST->PP = new Preprocessor(AST->getDiagnostics(), AST->ASTFileLangOpts, 
+                             /*Target=*/0, AST->getSourceManager(), HeaderInfo, 
+                             *AST, 
+                             /*IILookup=*/0,
+                             /*OwnsHeaderSearch=*/false,
+                             /*DelayInitialization=*/true);
+
   Reader.reset(new ASTReader(AST->getSourceManager(), AST->getFileManager(),
                              AST->getDiagnostics()));
   
@@ -586,8 +615,9 @@
   llvm::CrashRecoveryContextCleanupRegistrar<ASTReader>
     ReaderCleanup(Reader.get());
 
-  Reader->setListener(new ASTInfoCollector(AST->ASTFileLangOpts, HeaderInfo, 
-                                           TargetTriple, Predefines, Counter));
+  Reader->setListener(new ASTInfoCollector(*AST->PP,
+                                           AST->ASTFileLangOpts, HeaderInfo, 
+                                           AST->Target, Predefines, Counter));
 
   switch (Reader->ReadAST(Filename, serialization::MK_MainFile)) {
   case ASTReader::Success:
@@ -602,21 +632,6 @@
   AST->OriginalSourceFile = Reader->getOriginalSourceFile();
 
   // AST file loaded successfully. Now create the preprocessor.
-
-  // Get information about the target being compiled for.
-  //
-  // FIXME: This is broken, we should store the TargetOptions in the AST file.
-  TargetOptions TargetOpts;
-  TargetOpts.ABI = "";
-  TargetOpts.CXXABI = "";
-  TargetOpts.CPU = "";
-  TargetOpts.Features.clear();
-  TargetOpts.Triple = TargetTriple;
-  AST->Target = TargetInfo::CreateTargetInfo(AST->getDiagnostics(),
-                                             TargetOpts);
-  AST->PP = new Preprocessor(AST->getDiagnostics(), AST->ASTFileLangOpts, 
-                             *AST->Target, AST->getSourceManager(), HeaderInfo, 
-                             *AST);
   Preprocessor &PP = *AST->PP;
 
   PP.setPredefines(Reader->getSuggestedPredefines());
diff --git a/lib/Frontend/CompilerInstance.cpp b/lib/Frontend/CompilerInstance.cpp
index 344e77b..de950da 100644
--- a/lib/Frontend/CompilerInstance.cpp
+++ b/lib/Frontend/CompilerInstance.cpp
@@ -200,7 +200,7 @@
   
   // Create the Preprocessor.
   HeaderSearch *HeaderInfo = new HeaderSearch(getFileManager());
-  PP = new Preprocessor(getDiagnostics(), getLangOpts(), getTarget(),
+  PP = new Preprocessor(getDiagnostics(), getLangOpts(), &getTarget(),
                         getSourceManager(), *HeaderInfo, *this, PTHMgr,
                         /*OwnsHeaderSearch=*/true);
   
diff --git a/lib/Lex/Preprocessor.cpp b/lib/Lex/Preprocessor.cpp
index f003490..e189a9d 100644
--- a/lib/Lex/Preprocessor.cpp
+++ b/lib/Lex/Preprocessor.cpp
@@ -50,75 +50,25 @@
 ExternalPreprocessorSource::~ExternalPreprocessorSource() { }
 
 Preprocessor::Preprocessor(Diagnostic &diags, LangOptions &opts,
-                           const TargetInfo &target, SourceManager &SM,
+                           const TargetInfo *target, SourceManager &SM,
                            HeaderSearch &Headers, ModuleLoader &TheModuleLoader,
                            IdentifierInfoLookup* IILookup,
-                           bool OwnsHeaders)
+                           bool OwnsHeaders,
+                           bool DelayInitialization)
   : Diags(&diags), Features(opts), Target(target),FileMgr(Headers.getFileMgr()),
     SourceMgr(SM), HeaderInfo(Headers), TheModuleLoader(TheModuleLoader),
     ExternalSource(0), 
-    Identifiers(opts, IILookup), BuiltinInfo(Target), CodeComplete(0),
+    Identifiers(opts, IILookup), CodeComplete(0),
     CodeCompletionFile(0), SkipMainFilePreamble(0, true), CurPPLexer(0), 
     CurDirLookup(0), Callbacks(0), MacroArgCache(0), Record(0), MIChainHead(0),
-    MICache(0) {
-  ScratchBuf = new ScratchBuffer(SourceMgr);
-  CounterValue = 0; // __COUNTER__ starts at 0.
+    MICache(0) 
+{
   OwnsHeaderSearch = OwnsHeaders;
-
-  // Clear stats.
-  NumDirectives = NumDefined = NumUndefined = NumPragma = 0;
-  NumIf = NumElse = NumEndif = 0;
-  NumEnteredSourceFiles = 0;
-  NumMacroExpanded = NumFnMacroExpanded = NumBuiltinMacroExpanded = 0;
-  NumFastMacroExpanded = NumTokenPaste = NumFastTokenPaste = 0;
-  MaxIncludeStackDepth = 0;
-  NumSkipped = 0;
-
-  // Default to discarding comments.
-  KeepComments = false;
-  KeepMacroComments = false;
-  SuppressIncludeNotFoundError = false;
-
-  // Macro expansion is enabled.
-  DisableMacroExpansion = false;
-  InMacroArgs = false;
-  NumCachedTokenLexers = 0;
-
-  CachedLexPos = 0;
-
-  // We haven't read anything from the external source.
-  ReadMacrosFromExternalSource = false;
-
-  LexDepth = 0;
-      
-  // "Poison" __VA_ARGS__, which can only appear in the expansion of a macro.
-  // This gets unpoisoned where it is allowed.
-  (Ident__VA_ARGS__ = getIdentifierInfo("__VA_ARGS__"))->setIsPoisoned();
-  SetPoisonReason(Ident__VA_ARGS__,diag::ext_pp_bad_vaargs_use);
-
-  // Initialize the pragma handlers.
-  PragmaHandlers = new PragmaNamespace(StringRef());
-  RegisterBuiltinPragmas();
-
-  // Initialize builtin macros like __LINE__ and friends.
-  RegisterBuiltinMacros();
-
-  if(Features.Borland) {
-    Ident__exception_info        = getIdentifierInfo("_exception_info");
-    Ident___exception_info       = getIdentifierInfo("__exception_info");
-    Ident_GetExceptionInfo       = getIdentifierInfo("GetExceptionInformation");
-    Ident__exception_code        = getIdentifierInfo("_exception_code");
-    Ident___exception_code       = getIdentifierInfo("__exception_code");
-    Ident_GetExceptionCode       = getIdentifierInfo("GetExceptionCode");
-    Ident__abnormal_termination  = getIdentifierInfo("_abnormal_termination");
-    Ident___abnormal_termination = getIdentifierInfo("__abnormal_termination");
-    Ident_AbnormalTermination    = getIdentifierInfo("AbnormalTermination");
-  } else {
-    Ident__exception_info = Ident__exception_code = Ident__abnormal_termination = 0;
-    Ident___exception_info = Ident___exception_code = Ident___abnormal_termination = 0;
-    Ident_GetExceptionInfo = Ident_GetExceptionCode = Ident_AbnormalTermination = 0;
+  
+  if (!DelayInitialization) {
+    assert(Target && "Must provide target information for PP initialization");
+    Initialize(*Target);
   }
-
 }
 
 Preprocessor::~Preprocessor() {
@@ -157,6 +107,72 @@
   delete Callbacks;
 }
 
+void Preprocessor::Initialize(const TargetInfo &Target) {
+  assert((!this->Target || this->Target == &Target) &&
+         "Invalid override of target information");
+  this->Target = &Target;
+  
+  // Initialize information about built-ins.
+  BuiltinInfo.InitializeTarget(Target);
+  
+  ScratchBuf = new ScratchBuffer(SourceMgr);
+  CounterValue = 0; // __COUNTER__ starts at 0.
+  
+  // Clear stats.
+  NumDirectives = NumDefined = NumUndefined = NumPragma = 0;
+  NumIf = NumElse = NumEndif = 0;
+  NumEnteredSourceFiles = 0;
+  NumMacroExpanded = NumFnMacroExpanded = NumBuiltinMacroExpanded = 0;
+  NumFastMacroExpanded = NumTokenPaste = NumFastTokenPaste = 0;
+  MaxIncludeStackDepth = 0;
+  NumSkipped = 0;
+  
+  // Default to discarding comments.
+  KeepComments = false;
+  KeepMacroComments = false;
+  SuppressIncludeNotFoundError = false;
+  
+  // Macro expansion is enabled.
+  DisableMacroExpansion = false;
+  InMacroArgs = false;
+  NumCachedTokenLexers = 0;
+  
+  CachedLexPos = 0;
+  
+  // We haven't read anything from the external source.
+  ReadMacrosFromExternalSource = false;
+  
+  LexDepth = 0;
+  
+  // "Poison" __VA_ARGS__, which can only appear in the expansion of a macro.
+  // This gets unpoisoned where it is allowed.
+  (Ident__VA_ARGS__ = getIdentifierInfo("__VA_ARGS__"))->setIsPoisoned();
+  SetPoisonReason(Ident__VA_ARGS__,diag::ext_pp_bad_vaargs_use);
+  
+  // Initialize the pragma handlers.
+  PragmaHandlers = new PragmaNamespace(StringRef());
+  RegisterBuiltinPragmas();
+  
+  // Initialize builtin macros like __LINE__ and friends.
+  RegisterBuiltinMacros();
+  
+  if(Features.Borland) {
+    Ident__exception_info        = getIdentifierInfo("_exception_info");
+    Ident___exception_info       = getIdentifierInfo("__exception_info");
+    Ident_GetExceptionInfo       = getIdentifierInfo("GetExceptionInformation");
+    Ident__exception_code        = getIdentifierInfo("_exception_code");
+    Ident___exception_code       = getIdentifierInfo("__exception_code");
+    Ident_GetExceptionCode       = getIdentifierInfo("GetExceptionCode");
+    Ident__abnormal_termination  = getIdentifierInfo("_abnormal_termination");
+    Ident___abnormal_termination = getIdentifierInfo("__abnormal_termination");
+    Ident_AbnormalTermination    = getIdentifierInfo("AbnormalTermination");
+  } else {
+    Ident__exception_info = Ident__exception_code = Ident__abnormal_termination = 0;
+    Ident___exception_info = Ident___exception_code = Ident___abnormal_termination = 0;
+    Ident_GetExceptionInfo = Ident_GetExceptionCode = Ident_AbnormalTermination = 0;
+  } 
+}
+
 void Preprocessor::setPTHManager(PTHManager* pm) {
   PTH.reset(pm);
   FileMgr.addStatCache(PTH->createStatCache());