Remove runtime support for exclusivity warnings.

Author: atrick

include/swift/ABI/MetadataValues.h

@@ -997,10 +997,6 @@ enum class ExclusivityFlags : uintptr_t {
   // Read or Modify).
   ActionMask       = 0x1,
 
-#ifndef NDEBUG
-  // Downgrade exclusivity failures to a warning. Only used for unit testing.
-  WarningOnly      = 0x10,
-#endif
   // The runtime should track this access to check against subsequent accesses.
   Tracking         = 0x20
 };
@@ -1016,13 +1012,6 @@ static inline ExclusivityFlags getAccessAction(ExclusivityFlags flags) {
   return ExclusivityFlags(uintptr_t(flags)
                         & uintptr_t(ExclusivityFlags::ActionMask));
 }
-static inline bool isWarningOnly(ExclusivityFlags flags) {
-#ifndef NDEBUG
-  return uintptr_t(flags) & uintptr_t(ExclusivityFlags::WarningOnly);
-#else
-  return false;
-#endif
-}
 static inline bool isTracking(ExclusivityFlags flags) {
   return uintptr_t(flags) & uintptr_t(ExclusivityFlags::Tracking);
 }

stdlib/public/runtime/Exclusivity.cpp

@@ -50,15 +50,6 @@ LLVM_ATTRIBUTE_ALWAYS_INLINE
 static void reportExclusivityConflict(ExclusivityFlags oldAction, void *oldPC,
                                       ExclusivityFlags newFlags, void *newPC,
                                       void *pointer) {
-  static std::atomic<long> reportedConflicts{0};
-  constexpr long maxReportedConflicts = 100;
-  // Don't report more that 100 conflicts. Hopefully, this will improve
-  // performance in case there are conflicts inside a tight loop.
-  if (reportedConflicts.fetch_add(1, std::memory_order_relaxed) >=
-      maxReportedConflicts) {
-    return;
-  }
-
   constexpr unsigned maxMessageLength = 100;
   constexpr unsigned maxAccessDescriptionLength = 50;
   char message[maxMessageLength];
@@ -87,9 +78,6 @@ static void reportExclusivityConflict(ExclusivityFlags oldAction, void *oldPC,
   constexpr unsigned framesToSkip = 1;
   printCurrentBacktrace(framesToSkip);
 
-  // Should be inlined away in release builds.
-  bool keepGoing = isWarningOnly(newFlags);
-
   RuntimeErrorDetails::Thread secondaryThread = {
     .description = oldAccess,
     .numFrames = 1,
@@ -104,17 +92,7 @@ static void reportExclusivityConflict(ExclusivityFlags oldAction, void *oldPC,
     .numExtraThreads = 1,
     .threads = &secondaryThread
   };
-  uintptr_t flags = RuntimeErrorFlagNone;
-  if (!keepGoing)
-    flags = RuntimeErrorFlagFatal;
-  _swift_reportToDebugger(flags, message, &details);
-
-  if (keepGoing) {
-    return;
-  }
-
-  // 0 means no backtrace will be printed.
-  fatalError(0, "Fatal access conflict detected.\n");
+  _swift_reportToDebugger(RuntimeErrorFlagFatal, message, &details);
 }
 
 namespace {
@@ -201,8 +179,8 @@ class AccessSet {
       reportExclusivityConflict(cur->getAccessAction(), cur->PC,
                                 flags, pc, pointer);
 
-      // If we're only warning, don't report multiple conflicts.
-      break;
+      // 0 means no backtrace will be printed.
+      fatalError(0, "Fatal access conflict detected.\n");
     }
     if (!isTracking(flags))
       return false;