unique_ptr-ify FileSystemStatCache::setNextStatCache

And in the process, discover that FileManager::removeStatCache had a
double-delete when removing an element from the middle of the list (at
the beginning or the end of the list, there was no problem) and add a
unit test to exercise the code path (which successfully crashed when run
(with modifications to match the old API) without this patch applied)

llvm-svn: 215388

4 files changed, 13 insertions, 10 deletions

diff --git a/clang/lib/Basic/FileManager.cpp b/clang/lib/Basic/FileManager.cpp
index 94bd3f8ccfd..e4a7f1e2575 100644
--- a/clang/lib/Basic/FileManager.cpp
+++ b/clang/lib/Basic/FileManager.cpp
@@ -64,20 +64,20 @@ FileManager::~FileManager() {
     delete VirtualDirectoryEntries[i];
 }
 
-void FileManager::addStatCache(FileSystemStatCache *statCache,
+void FileManager::addStatCache(std::unique_ptr<FileSystemStatCache> statCache,
                                bool AtBeginning) {
   assert(statCache && "No stat cache provided?");
   if (AtBeginning || !StatCache.get()) {
-    statCache->setNextStatCache(StatCache.release());
-    StatCache.reset(statCache);
+    statCache->setNextStatCache(std::move(StatCache));
+    StatCache = std::move(statCache);
     return;
   }
   
   FileSystemStatCache *LastCache = StatCache.get();
   while (LastCache->getNextStatCache())
     LastCache = LastCache->getNextStatCache();
-  
-  LastCache->setNextStatCache(statCache);
+
+  LastCache->setNextStatCache(std::move(statCache));
 }
 
 void FileManager::removeStatCache(FileSystemStatCache *statCache) {
@@ -96,7 +96,7 @@ void FileManager::removeStatCache(FileSystemStatCache *statCache) {
     PrevCache = PrevCache->getNextStatCache();
   
   assert(PrevCache && "Stat cache not found for removal");
-  PrevCache->setNextStatCache(statCache->getNextStatCache());
+  PrevCache->setNextStatCache(statCache->takeNextStatCache());
 }
 
 void FileManager::clearStatCaches() {
diff --git a/clang/lib/Frontend/CacheTokens.cpp b/clang/lib/Frontend/CacheTokens.cpp
index 14f7027e468..23f22ada7fc 100644
--- a/clang/lib/Frontend/CacheTokens.cpp
+++ b/clang/lib/Frontend/CacheTokens.cpp
@@ -572,8 +572,10 @@ void clang::CacheTokens(Preprocessor &PP, llvm::raw_fd_ostream* OS) {
   PTHWriter PW(*OS, PP);
 
   // Install the 'stat' system call listener in the FileManager.
-  StatListener *StatCache = new StatListener(PW.getPM());
-  PP.getFileManager().addStatCache(StatCache, /*AtBeginning=*/true);
+  auto StatCacheOwner = llvm::make_unique<StatListener>(PW.getPM());
+  StatListener *StatCache = StatCacheOwner.get();
+  PP.getFileManager().addStatCache(std::move(StatCacheOwner),
+                                   /*AtBeginning=*/true);
 
   // Lex through the entire file.  This will populate SourceManager with
   // all of the header information.
diff --git a/clang/lib/Lex/PTHLexer.cpp b/clang/lib/Lex/PTHLexer.cpp
index fce31c4be29..4e2a755f8c6 100644
--- a/clang/lib/Lex/PTHLexer.cpp
+++ b/clang/lib/Lex/PTHLexer.cpp
@@ -732,6 +732,6 @@ public:
 };
 } // end anonymous namespace
 
-FileSystemStatCache *PTHManager::createStatCache() {
-  return new PTHStatCache(*((PTHFileLookup*) FileLookup));
+std::unique_ptr<FileSystemStatCache> PTHManager::createStatCache() {
+  return llvm::make_unique<PTHStatCache>(*((PTHFileLookup *)FileLookup));
 }
diff --git a/clang/lib/Lex/Preprocessor.cpp b/clang/lib/Lex/Preprocessor.cpp
index ab11fabbbce..fd0e48c66c8 100644
--- a/clang/lib/Lex/Preprocessor.cpp
+++ b/clang/lib/Lex/Preprocessor.cpp
@@ -27,6 +27,7 @@
 
 #include "clang/Lex/Preprocessor.h"
 #include "clang/Basic/FileManager.h"
+#include "clang/Basic/FileSystemStatCache.h"
 #include "clang/Basic/SourceManager.h"
 #include "clang/Basic/TargetInfo.h"
 #include "clang/Lex/CodeCompletionHandler.h"