Introduce a new libclang parsing flag,

CXTranslationUnit_NestedMacroInstantiations, which indicates whether
we want to see "nested" macro instantiations (e.g., those that occur
inside other macro instantiations) within the detailed preprocessing
record. Many clients (e.g., those that only care about visible tokens)
don't care about this information, and in code that uses preprocessor
metaprogramming, this information can have a very high cost.

Addresses <rdar://problem/9389320>.

llvm-svn: 130990

5 files changed, 25 insertions, 9 deletions

diff --git a/clang/lib/Frontend/ASTUnit.cpp b/clang/lib/Frontend/ASTUnit.cpp
index 0d0fecdcf44..8827116f2e4 100644
--- a/clang/lib/Frontend/ASTUnit.cpp
+++ b/clang/lib/Frontend/ASTUnit.cpp
@@ -102,6 +102,7 @@ ASTUnit::ASTUnit(bool _MainFileIsAST)
     ConcurrencyCheckValue(CheckUnlocked), 
     PreambleRebuildCounter(0), SavedMainFileBuffer(0), PreambleBuffer(0),
     ShouldCacheCodeCompletionResults(false),
+    NestedMacroInstantiations(true),
     CompletionCacheTopLevelHashValue(0),
     PreambleTopLevelHashValue(0),
     CurrentTopLevelHashValue(0),
@@ -927,6 +928,8 @@ bool ASTUnit::Parse(llvm::MemoryBuffer *OverrideMainBuffer) {
   // If the main file has been overridden due to the use of a preamble,
   // make that override happen and introduce the preamble.
   PreprocessorOptions &PreprocessorOpts = Clang->getPreprocessorOpts();
+  PreprocessorOpts.DetailedRecordIncludesNestedMacroInstantiations
+    = NestedMacroInstantiations;
   std::string PriorImplicitPCHInclude;
   if (OverrideMainBuffer) {
     PreprocessorOpts.addRemappedFile(OriginalSourceFile, OverrideMainBuffer);
@@ -1712,7 +1715,8 @@ ASTUnit *ASTUnit::LoadFromCompilerInvocation(CompilerInvocation *CI,
                                              bool CaptureDiagnostics,
                                              bool PrecompilePreamble,
                                              bool CompleteTranslationUnit,
-                                             bool CacheCodeCompletionResults) {  
+                                             bool CacheCodeCompletionResults,
+                                             bool NestedMacroInstantiations) {  
   // Create the AST unit.
   llvm::OwningPtr<ASTUnit> AST;
   AST.reset(new ASTUnit(false));
@@ -1723,6 +1727,7 @@ ASTUnit *ASTUnit::LoadFromCompilerInvocation(CompilerInvocation *CI,
   AST->CompleteTranslationUnit = CompleteTranslationUnit;
   AST->ShouldCacheCodeCompletionResults = CacheCodeCompletionResults;
   AST->Invocation = CI;
+  AST->NestedMacroInstantiations = NestedMacroInstantiations;
   
   // Recover resources if we crash before exiting this method.
   llvm::CrashRecoveryContextCleanupRegistrar<ASTUnit>
@@ -1747,7 +1752,8 @@ ASTUnit *ASTUnit::LoadFromCommandLine(const char **ArgBegin,
                                       bool CompleteTranslationUnit,
                                       bool CacheCodeCompletionResults,
                                       bool CXXPrecompilePreamble,
-                                      bool CXXChainedPCH) {
+                                      bool CXXChainedPCH,
+                                      bool NestedMacroInstantiations) {
   if (!Diags.getPtr()) {
     // No diagnostics engine was provided, so create our own diagnostics object
     // with the default options.
@@ -1814,6 +1820,7 @@ ASTUnit *ASTUnit::LoadFromCommandLine(const char **ArgBegin,
   AST->NumStoredDiagnosticsInPreamble = StoredDiagnostics.size();
   AST->StoredDiagnostics.swap(StoredDiagnostics);
   AST->Invocation = CI;
+  AST->NestedMacroInstantiations = NestedMacroInstantiations;
   
   // Recover resources if we crash before exiting this method.
   llvm::CrashRecoveryContextCleanupRegistrar<ASTUnit>
@@ -2265,6 +2272,9 @@ void ASTUnit::CodeComplete(llvm::StringRef File, unsigned Line, unsigned Column,
     PreprocessorOpts.PrecompiledPreambleBytes.second = false;
   }
 
+  // Disable the preprocessing record
+  PreprocessorOpts.DetailedRecord = false;
+  
   llvm::OwningPtr<SyntaxOnlyAction> Act;
   Act.reset(new SyntaxOnlyAction);
   if (Act->BeginSourceFile(*Clang.get(), Clang->getFrontendOpts().Inputs[0].second,
diff --git a/clang/lib/Frontend/CompilerInstance.cpp b/clang/lib/Frontend/CompilerInstance.cpp
index ace3c5adb10..38fcfe3c471 100644
--- a/clang/lib/Frontend/CompilerInstance.cpp
+++ b/clang/lib/Frontend/CompilerInstance.cpp
@@ -227,7 +227,8 @@ CompilerInstance::createPreprocessor(Diagnostic &Diags,
   }
 
   if (PPOpts.DetailedRecord)
-    PP->createPreprocessingRecord();
+    PP->createPreprocessingRecord(
+                       PPOpts.DetailedRecordIncludesNestedMacroInstantiations);
   
   InitializePreprocessor(*PP, PPOpts, HSOpts, FEOpts);
 
diff --git a/clang/lib/Lex/PreprocessingRecord.cpp b/clang/lib/Lex/PreprocessingRecord.cpp
index 9555611dc59..0c8d948ce0a 100644
--- a/clang/lib/Lex/PreprocessingRecord.cpp
+++ b/clang/lib/Lex/PreprocessingRecord.cpp
@@ -45,8 +45,9 @@ void PreprocessingRecord::MaybeLoadPreallocatedEntities() const {
   ExternalSource->ReadPreprocessedEntities();
 }
 
-PreprocessingRecord::PreprocessingRecord()
-  : ExternalSource(0), NumPreallocatedEntities(0), 
+PreprocessingRecord::PreprocessingRecord(bool IncludeNestedMacroInstantiations)
+  : IncludeNestedMacroInstantiations(IncludeNestedMacroInstantiations),
+    ExternalSource(0), NumPreallocatedEntities(0), 
     LoadedPreallocatedEntities(false)
 {
 }
@@ -120,6 +121,9 @@ MacroDefinition *PreprocessingRecord::findMacroDefinition(const MacroInfo *MI) {
 }
 
 void PreprocessingRecord::MacroExpands(const Token &Id, const MacroInfo* MI) {
+  if (!IncludeNestedMacroInstantiations && Id.getLocation().isMacroID())
+    return;
+
   if (MacroDefinition *Def = findMacroDefinition(MI))
     PreprocessedEntities.push_back(
                        new (*this) MacroInstantiation(Id.getIdentifierInfo(),
diff --git a/clang/lib/Lex/Preprocessor.cpp b/clang/lib/Lex/Preprocessor.cpp
index 31fd667a651..fdc18f87818 100644
--- a/clang/lib/Lex/Preprocessor.cpp
+++ b/clang/lib/Lex/Preprocessor.cpp
@@ -527,10 +527,11 @@ CommentHandler::~CommentHandler() { }
 
 CodeCompletionHandler::~CodeCompletionHandler() { }
 
-void Preprocessor::createPreprocessingRecord() {
+void Preprocessor::createPreprocessingRecord(
+                                      bool IncludeNestedMacroInstantiations) {
   if (Record)
     return;
   
-  Record = new PreprocessingRecord;
+  Record = new PreprocessingRecord(IncludeNestedMacroInstantiations);
   addPPCallbacks(Record);
 }
diff --git a/clang/lib/Serialization/ASTReader.cpp b/clang/lib/Serialization/ASTReader.cpp
index bad18ff02e2..bdc46f590fa 100644
--- a/clang/lib/Serialization/ASTReader.cpp
+++ b/clang/lib/Serialization/ASTReader.cpp
@@ -2382,7 +2382,7 @@ ASTReader::ASTReadResult ASTReader::ReadAST(const std::string &FileName,
       PP->getHeaderSearchInfo().SetExternalLookup(this);
     if (TotalNumPreallocatedPreprocessingEntities > 0) {
       if (!PP->getPreprocessingRecord())
-        PP->createPreprocessingRecord();
+        PP->createPreprocessingRecord(true);
       PP->getPreprocessingRecord()->SetExternalSource(*this,
                                      TotalNumPreallocatedPreprocessingEntities);
     }
@@ -2581,7 +2581,7 @@ void ASTReader::setPreprocessor(Preprocessor &pp) {
     TotalNum += Chain[I]->NumPreallocatedPreprocessingEntities;
   if (TotalNum) {
     if (!PP->getPreprocessingRecord())
-      PP->createPreprocessingRecord();
+      PP->createPreprocessingRecord(true);
     PP->getPreprocessingRecord()->SetExternalSource(*this, TotalNum);
   }
 }