commit 1b7ed91e44a8fdcb3217077204d60e7fc8d4561f
author Argyrios Kyrtzidis <akyrtzi@gmail.com> Thu Feb 27 04:11:59 2014 +0000
committer Argyrios Kyrtzidis <akyrtzi@gmail.com> Thu Feb 27 04:11:59 2014 +0000
tree 22268eb650ebd65e801631b863d68ea4a3d6bd74
parent 08301dee468848e405d2a9c2ca08ad8af042be52

[ASTUnit] Fix use-after-free bug in ASTUnit::getMainBufferWithPrecompiledPreamble().

With r197755 we started reading the contents of buffer file entries, but the
buffers may point to ASTReader blobs that have been disposed.

Fix this by having the CompilerInstance object keep a reference to the ASTReader
as well as having the ASTContext keep reference to the ExternalASTSource.

This was very difficult to construct a test case for.
rdar://16149782

llvm-svn: 202346

clang/lib/Frontend/CompilerInstance.cpp

diff --git a/clang/lib/Frontend/CompilerInstance.cpp b/clang/lib/Frontend/CompilerInstance.cpp
index 3fe8f0e..cdc4b64 100644
--- a/clang/lib/Frontend/CompilerInstance.cpp
+++ b/clang/lib/Frontend/CompilerInstance.cpp
@@ -104,6 +104,13 @@
 void CompilerInstance::setCodeCompletionConsumer(CodeCompleteConsumer *Value) {
   CompletionConsumer.reset(Value);
 }
+ 
+IntrusiveRefCntPtr<ASTReader> CompilerInstance::getModuleManager() const {
+  return ModuleManager;
+}
+void CompilerInstance::setModuleManager(IntrusiveRefCntPtr<ASTReader> Reader) {
+  ModuleManager = Reader;
+}
 
 // Diagnostics
 static void SetUpDiagnosticLog(DiagnosticOptions *DiagOpts,
@@ -301,16 +308,16 @@
                                                   bool DisablePCHValidation,
                                                 bool AllowPCHWithCompilerErrors,
                                                  void *DeserializationListener){
-  OwningPtr<ExternalASTSource> Source;
+  IntrusiveRefCntPtr<ExternalASTSource> Source;
   bool Preamble = getPreprocessorOpts().PrecompiledPreambleBytes.first != 0;
-  Source.reset(createPCHExternalASTSource(Path, getHeaderSearchOpts().Sysroot,
+  Source = createPCHExternalASTSource(Path, getHeaderSearchOpts().Sysroot,
                                           DisablePCHValidation,
                                           AllowPCHWithCompilerErrors,
                                           getPreprocessor(), getASTContext(),
                                           DeserializationListener,
                                           Preamble,
-                                       getFrontendOpts().UseGlobalModuleIndex));
-  ModuleManager = static_cast<ASTReader*>(Source.get());
+                                       getFrontendOpts().UseGlobalModuleIndex);
+  ModuleManager = static_cast<ASTReader*>(Source.getPtr());
   getASTContext().setExternalSource(Source);
 }
 
@@ -1176,9 +1183,7 @@
         getASTContext().setASTMutationListener(
           getASTConsumer().GetASTMutationListener());
       }
-      OwningPtr<ExternalASTSource> Source;
-      Source.reset(ModuleManager);
-      getASTContext().setExternalSource(Source);
+      getASTContext().setExternalSource(ModuleManager);
       if (hasSema())
         ModuleManager->InitializeSema(getSema());
       if (hasASTConsumer())