TranslationUnit now owns IdentifierTable, TargetInfo, and Selectors objects

when it is constructed via deserialization.  This is done by recording a flag
indicating that this is the case, and it deletes these objects by getting
the references stored in the ASTContext object.  This fixes some memory
leaks that occurs when we deserialize translation units from bitcode files.

The rationale between having TranslationUnit sometimes own these objects and
sometimes not is that a TranslationUnit object can be constructed from
state generated by the parser (Preprocessor; semantic analyzer, etc.), and thus
in these cases won't own the IdentifierTable or Selectors, etc.  During
deserialization, there is no Preprocessor, so somebody needs to own these
objects in order for them to be properly reclaimed.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@50149 91177308-0d34-0410-b5e6-96231b3b80d8

5 files changed, 54 insertions, 24 deletions

diff --git a/Driver/ASTConsumers.cpp b/Driver/ASTConsumers.cpp
index eaee94e51d..2f04ab78d4 100644
--- a/Driver/ASTConsumers.cpp
+++ b/Driver/ASTConsumers.cpp
@@ -826,20 +826,24 @@ namespace {
 class ASTSerializer : public ASTConsumer {
 protected:
   Diagnostic &Diags;
-  TranslationUnit TU;
+  const LangOptions& lang;
+  TranslationUnit* TU;
+
 public:
   ASTSerializer(Diagnostic& diags, const LangOptions& LO)
-    : Diags(diags), TU(LO) {}
+    : Diags(diags), lang(LO), TU(0) {}
+    
+  virtual ~ASTSerializer() { delete TU; }
   
   virtual void Initialize(ASTContext &Context) {
-    TU.setContext(&Context);
+    if (!TU) TU = new TranslationUnit(Context, lang);
   }
   
   virtual void HandleTopLevelDecl(Decl *D) {
     if (Diags.hasErrorOccurred())
       return;
     
-    TU.AddTopLevelDecl(D);
+    if (TU) TU->AddTopLevelDecl(D);
   }
 };
     
@@ -851,7 +855,7 @@ public:
   : ASTSerializer(diags,LO), FName(F) {}    
   
   ~SingleFileSerializer() {
-    EmitASTBitcodeFile(TU,FName);
+    EmitASTBitcodeFile(TU, FName);
   }
 };
 
@@ -863,7 +867,11 @@ public:
   : ASTSerializer(diags,LO), EmitDir(dir) {}
   
   ~BuildSerializer() {
-    SourceManager& SourceMgr = TU.getASTContext()->getSourceManager();
+
+    if (!TU)
+      return;
+    
+    SourceManager& SourceMgr = TU->getContext().getSourceManager();
     unsigned ID = SourceMgr.getMainFileID();
     assert (ID && "MainFileID not set!");
     const FileEntry* FE = SourceMgr.getFileEntryForID(ID);
@@ -887,7 +895,7 @@ public:
             
     sprintf(&buf[0], "%s-%llX.ast", FE->getName(), (uint64_t) FE->getInode());
     FName.appendComponent(&buf[0]);    
-    EmitASTBitcodeFile(TU,FName);
+    EmitASTBitcodeFile(TU, FName);
     
     // Now emit the sources.
     
diff --git a/Driver/SerializationTest.cpp b/Driver/SerializationTest.cpp
index 086d5587e9..6e9309dc28 100644
--- a/Driver/SerializationTest.cpp
+++ b/Driver/SerializationTest.cpp
@@ -33,21 +33,22 @@ using namespace clang;
 namespace {
   
 class SerializationTest : public ASTConsumer {
-  TranslationUnit TU;
+  llvm::OwningPtr<TranslationUnit> TU;
   Diagnostic &Diags;
   FileManager &FMgr;  
+  const LangOptions& lopts;
 public:  
   SerializationTest(Diagnostic &d, FileManager& fmgr, const LangOptions& LOpts)
-                    : TU(LOpts), Diags(d), FMgr(fmgr) {}
+                    : Diags(d), FMgr(fmgr), lopts(LOpts) {}
   
   ~SerializationTest();
 
   virtual void Initialize(ASTContext& context) {
-    TU.setContext(&context);
+    if (!TU) TU.reset(new TranslationUnit(context, lopts));
   }  
 
   virtual void HandleTopLevelDecl(Decl *D) {
-    TU.AddTopLevelDecl(D);
+    TU->AddTopLevelDecl(D);
   }
   
 private:
@@ -73,12 +74,12 @@ bool SerializationTest::Serialize(llvm::sys::Path& Filename,
     assert (DeclPP && "Could not open file for printing out decls.");
     llvm::OwningPtr<ASTConsumer> FilePrinter(CreateASTPrinter(&DeclPP));
     
-    for (TranslationUnit::iterator I=TU.begin(), E=TU.end(); I!=E; ++I)
+    for (TranslationUnit::iterator I=TU->begin(), E=TU->end(); I!=E; ++I)
       FilePrinter->HandleTopLevelDecl(*I);
   }
   
   // Serialize the translation unit.
-  return EmitASTBitcodeFile(TU,Filename);
+  return EmitASTBitcodeFile(*TU,Filename);
 }
 
 bool SerializationTest::Deserialize(llvm::sys::Path& Filename,
diff --git a/Driver/clang.cpp b/Driver/clang.cpp
index 144ab4e65a..f077952ea2 100644
--- a/Driver/clang.cpp
+++ b/Driver/clang.cpp
@@ -1274,7 +1274,7 @@ static void ProcessSerializedFile(const std::string& InFile, Diagnostic& Diag,
     exit (1);
   }
   
-  llvm::OwningPtr<TranslationUnit> TU(ReadASTBitcodeFile(Filename,FileMgr));
+  llvm::OwningPtr<TranslationUnit> TU(ReadASTBitcodeFile(Filename, FileMgr));
   
   if (!TU) {
     fprintf(stderr, "error: file '%s' could not be deserialized\n", 
@@ -1294,7 +1294,7 @@ static void ProcessSerializedFile(const std::string& InFile, Diagnostic& Diag,
     exit (1);
   }
   
-  Consumer->Initialize(*TU->getContext());
+  Consumer->Initialize(TU->getContext());
   
   // FIXME: We need to inform Consumer about completed TagDecls as well.
   for (TranslationUnit::iterator I=TU->begin(), E=TU->end(); I!=E; ++I)
diff --git a/include/clang/AST/TranslationUnit.h b/include/clang/AST/TranslationUnit.h
index 0c7d0348da..6aa3a40b87 100644
--- a/include/clang/AST/TranslationUnit.h
+++ b/include/clang/AST/TranslationUnit.h
@@ -34,19 +34,17 @@ class TranslationUnit {
   LangOptions LangOpts;
   ASTContext* Context;
   std::vector<Decl*> TopLevelDecls;
+  bool OwnsMetaData;
 
   // The default ctor is only invoked during deserialization.
-  explicit TranslationUnit() : Context(NULL) {}
+  explicit TranslationUnit() : Context(NULL), OwnsMetaData(true) {}
   
 public:
-  explicit TranslationUnit(const LangOptions& lopt)
-    : LangOpts(lopt), Context(NULL) {}
+  explicit TranslationUnit(ASTContext& Ctx, const LangOptions& lopt)
+    : LangOpts(lopt), Context(&Ctx), OwnsMetaData(false) {}
 
   ~TranslationUnit();
 
-  void setContext(ASTContext* context) { Context = context; }
-  ASTContext* getContext() const { return Context; }
-  
   const LangOptions& getLangOpts() const { return LangOpts; }
   const std::string& getSourceFile() const;
   
@@ -58,9 +56,12 @@ public:
   
   // Accessors
   const LangOptions& getLangOptions() const { return LangOpts; }
-  ASTContext*        getASTContext() { return Context; }
+
+  ASTContext&        getContext() { return *Context; }
+  const ASTContext&  getContext() const { return *Context; }
   
   /// AddTopLevelDecl - Add a top-level declaration to the translation unit.
+  ///  Ownership of the Decl is transfered to the TranslationUnit object.
   void AddTopLevelDecl(Decl* d) {
     TopLevelDecls.push_back(d);
   }
@@ -77,6 +78,9 @@ public:
 /// EmitASTBitcodeFile - Emit a translation unit to a bitcode file.
 bool EmitASTBitcodeFile(const TranslationUnit& TU, 
                         const llvm::sys::Path& Filename);
+  
+bool EmitASTBitcodeFile(const TranslationUnit* TU, 
+                        const llvm::sys::Path& Filename);
                      
 /// ReadASTBitcodeFile - Reconsitute a translation unit from a bitcode file.
 TranslationUnit* ReadASTBitcodeFile(const llvm::sys::Path& Filename,
diff --git a/lib/AST/TranslationUnit.cpp b/lib/AST/TranslationUnit.cpp
index 0198f6f1cf..5c043efeb3 100644
--- a/lib/AST/TranslationUnit.cpp
+++ b/lib/AST/TranslationUnit.cpp
@@ -33,11 +33,28 @@ enum { BasicMetadataBlock = 1,
 TranslationUnit::~TranslationUnit() {
   for (iterator I=begin(), E=end(); I!=E; ++I) 
     (*I)->Destroy(*Context);
+  
+  if (OwnsMetaData && Context) {
+    // The ASTContext object has the sole references to the IdentifierTable
+    // Selectors, and the Target information.  Go and delete them, since
+    // the TranslationUnit effectively owns them.
+    
+    delete &(Context->Idents);
+    delete &(Context->Selectors);
+    delete &(Context->Target);
+    delete Context;
+  }  
 }
 
+bool clang::EmitASTBitcodeFile(const TranslationUnit* TU,                                
+                               const llvm::sys::Path& Filename) {
+
+  return TU ? EmitASTBitcodeFile(*TU, Filename) : false;
+}
+  
 bool clang::EmitASTBitcodeFile(const TranslationUnit& TU, 
                                const llvm::sys::Path& Filename) {  
-
+  
   // Reserve 256K for bitstream buffer.
   std::vector<unsigned char> Buffer;
   Buffer.reserve(256*1024);
@@ -194,7 +211,7 @@ TranslationUnit* TranslationUnit::Create(llvm::Deserializer& Dezr,
   { // Read the TargetInfo.
     llvm::SerializedPtrID PtrID = Dezr.ReadPtrID();
     char* triple = Dezr.ReadCStr(NULL,0,true);
-    Dezr.RegisterPtr(PtrID,TargetInfo::CreateTargetInfo(std::string(triple)));
+    Dezr.RegisterPtr(PtrID, TargetInfo::CreateTargetInfo(std::string(triple)));
     delete [] triple;
   }