[hwasan] Verify Android TLS slot at startup.

Summary:
Add a check that TLS_SLOT_TSAN / TLS_SLOT_SANITIZER, whichever
android_get_tls_slot is using, is not conflicting with
TLS_SLOT_DLERROR.

Reviewers: rprichard, vitalybuka

Subscribers: srhines, kubamracek, llvm-commits

Differential Revision: https://reviews.llvm.org/D55587

llvm-svn: 348979

compiler-rt/lib/hwasan/hwasan.cc

@@ -283,6 +283,8 @@ void __hwasan_init() {
 
   __sanitizer_set_report_path(common_flags()->log_path);
 
+  AndroidTestTlsSlot();
+
   DisableCoreDumperIfNecessary();
 
   __hwasan_shadow_init();

compiler-rt/lib/hwasan/hwasan.h

@@ -154,6 +154,8 @@ void UpdateMemoryUsage();
 
 void AppendToErrorMessageBuffer(const char *buffer);
 
+void AndroidTestTlsSlot();
+
 }  // namespace __hwasan
 
 #define HWASAN_MALLOC_HOOK(ptr, size)       \

compiler-rt/lib/hwasan/hwasan_linux.cc

@@ -24,6 +24,7 @@
 #include "hwasan_thread.h"
 #include "hwasan_thread_list.h"
 
+#include <dlfcn.h>
 #include <elf.h>
 #include <link.h>
 #include <pthread.h>
@@ -283,6 +284,22 @@ uptr *GetCurrentThreadLongPtr() {
 }
 #endif
 
+#if SANITIZER_ANDROID
+void AndroidTestTlsSlot() {
+  uptr kMagicValue = 0x010203040A0B0C0D;
+  *(uptr *)get_android_tls_ptr() = kMagicValue;
+  dlerror();
+  if (*(uptr *)get_android_tls_ptr() != kMagicValue) {
+    Printf(
+        "ERROR: Incompatible version of Android: TLS_SLOT_SANITIZER(6) is used "
+        "for dlerror().\n");
+    Die();
+  }
+}
+#else
+void AndroidTestTlsSlot() {}
+#endif
+
 Thread *GetCurrentThread() {
   auto *R = (StackAllocationsRingBuffer*)GetCurrentThreadLongPtr();
   return hwasanThreadList().GetThreadByBufferAddress((uptr)(R->Next()));