For llvm::sys::ThreadLocalImpl instead of malloc'ing the platform-specific

thread local data, embed them in the class using a uint64_t and make sure
we get compiler errors if there's a platform where this is not big enough.

This makes ThreadLocal more safe for using it in conjunction with CrashRecoveryContext.

Related to crash in rdar://11434201.

llvm-svn: 158342

1 files changed, 5 insertions, 6 deletions

diff --git a/llvm/lib/Support/ThreadLocal.cpp b/llvm/lib/Support/ThreadLocal.cpp
index 08b12b658be..1030a2b97db 100644
--- a/llvm/lib/Support/ThreadLocal.cpp
+++ b/llvm/lib/Support/ThreadLocal.cpp
@@ -41,30 +41,29 @@ namespace llvm {
 using namespace sys;
 
 ThreadLocalImpl::ThreadLocalImpl() : data(0) {
-  pthread_key_t* key = new pthread_key_t;
+  typedef int SIZE_TOO_BIG[sizeof(pthread_key_t) <= sizeof(data) ? 1 : -1];
+  pthread_key_t* key = reinterpret_cast<pthread_key_t*>(&data);
   int errorcode = pthread_key_create(key, NULL);
   assert(errorcode == 0);
   (void) errorcode;
-  data = (void*)key;
 }
 
 ThreadLocalImpl::~ThreadLocalImpl() {
-  pthread_key_t* key = static_cast<pthread_key_t*>(data);
+  pthread_key_t* key = reinterpret_cast<pthread_key_t*>(&data);
   int errorcode = pthread_key_delete(*key);
   assert(errorcode == 0);
   (void) errorcode;
-  delete key;
 }
 
 void ThreadLocalImpl::setInstance(const void* d) {
-  pthread_key_t* key = static_cast<pthread_key_t*>(data);
+  pthread_key_t* key = reinterpret_cast<pthread_key_t*>(&data);
   int errorcode = pthread_setspecific(*key, d);
   assert(errorcode == 0);
   (void) errorcode;
 }
 
 const void* ThreadLocalImpl::getInstance() {
-  pthread_key_t* key = static_cast<pthread_key_t*>(data);
+  pthread_key_t* key = reinterpret_cast<pthread_key_t*>(&data);
   return pthread_getspecific(*key);
 }