[tsan] Detect races on modifying accesses in Swift code

This patch allows the Swift compiler to emit calls to `__tsan_external_write` before starting any modifying access, which will cause TSan to detect races on arrays, dictionaries and other classes defined in non-instrumented modules. Races on collections from the Swift standard library and user-defined structs and a frequent cause of subtle bugs and it's important that TSan detects those on top of existing LLVM IR instrumentation, which already detects races in direct memory accesses.

Differential Revision: https://reviews.llvm.org/D31630



git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@302050 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 2 insertions, 8 deletions

diff --git a/lib/tsan/rtl/tsan_rtl.h b/lib/tsan/rtl/tsan_rtl.h
index 8bf1c191a..e92a0f357 100644
--- a/lib/tsan/rtl/tsan_rtl.h
+++ b/lib/tsan/rtl/tsan_rtl.h
@@ -564,19 +564,13 @@ struct ScopedIgnoreInterceptors {
   }
 };
 
-enum ExternalTag : uptr {
-  kExternalTagNone = 0,
-  kExternalTagFirstUserAvailable = 1,
-  kExternalTagMax = 1024,
-  // Don't set kExternalTagMax over 65,536, since MBlock only stores tags
-  // as 16-bit values, see tsan_defs.h.
-};
 const char *GetObjectTypeFromTag(uptr tag);
+const char *GetReportHeaderFromTag(uptr tag);
 uptr TagFromShadowStackFrame(uptr pc);
 
 class ScopedReport {
  public:
-  explicit ScopedReport(ReportType typ);
+  explicit ScopedReport(ReportType typ, uptr tag = kExternalTagNone);
   ~ScopedReport();
 
   void AddMemoryAccess(uptr addr, uptr external_tag, Shadow s, StackTrace stack,