[lsan] Create a dummy SuspendedThreadsList for Fuchsia

[leonardchan]

Summary

As of d48f2d7c02743571075bb7812bb4c9e634e51ed1, the destructor for SuspendedThreadsList is protected, which leads to this error on our CI builders:

/b/s/w/ir/x/w/llvm-project/compiler-rt/lib/sanitizer_common/sanitizer_stoptheworld_fuchsia.cpp:35:26: error: temporary of type 'const __sanitizer::SuspendedThreadsList' has protected destructor
        params->callback({}, params->argument);
                         ^
/b/s/w/ir/x/w/llvm-project/compiler-rt/lib/sanitizer_common/sanitizer_stoptheworld.h:44:3: note: declared protected here
  ~SuspendedThreadsList() {}
  ^
1 error generated.

Although the threadslists aren't needed for Fuchsia's case, we can just make a dummy SuspendedThreadsList class for Fuchsia with an overriden destructor.

[leonardchan]

Unsure if this is the best way to go about it, so open to other solutions.

[phosek]

I have made the same change which is slightly simpler, see D90695, so LGTM.

compiler-rt/lib/lsan/lsan_common_fuchsia.cpp

36

This is not necessary, see D90695.

compiler-rt/lib/sanitizer_common/sanitizer_stoptheworld_fuchsia.cpp

30

This is not necessary, see D90695.

[leonardchan]

Abandoned since https://reviews.llvm.org/D90695 fixes this

compiler-rt/lib/lsan/lsan_common_fuchsia.cpp

 #include "sanitizer_common/sanitizer_flags.h"
 #include "sanitizer_common/sanitizer_thread_registry.h"
 
 // Ensure that the Zircon system ABI is linked in.
 #pragma comment(lib, "zircon")
 
 namespace __lsan {
 
+namespace {
+
+// Fuchsia does not need a threadslist. This class only exists to pass a dummy
+// threadslist to pass to the StopTheWorldCallback since SuspendedThreadsList
+// has a protected destructor.
+class DummySuspendedThreadsListFuchsia final : public SuspendedThreadsList {
+ public:
+  ~DummySuspendedThreadsListFuchsia(){}
+};
+
+}
+
 void InitializePlatformSpecificModules() {}
 
 LoadedModule *GetLinker() { return nullptr; }
 
 __attribute__((tls_model("initial-exec"))) THREADLOCAL int disable_counter;
 bool DisabledInThisThread() { return disable_counter > 0; }
 void DisableInThisThread() { disable_counter++; }
 void EnableInThisThread() {
__sanitizer_memory_snapshot(
           GetThreadRegistryLocked()->RunCallbackForEachThreadLocked(
               [](ThreadContextBase *tctx, void *arg) {
                 ForEachExtraStackRange(tctx->os_id, ForEachExtraStackRangeCb,
                                        arg);
               },
               &params->argument->frontier);
         }
 
-        params->callback({}, params->argument);
+        DummySuspendedThreadsListFuchsia threadlist;
+        params->callback(threadlist, params->argument);
       },
       &params);
 
   UnlockAllocator();
   UnlockThreadRegistry();
 }
 
 }  // namespace __lsan
 
 // This is declared (in extern "C") by <zircon/sanitizer.h>.
 // _Exit calls this directly to intercept and change the status value.
 int __sanitizer_process_exit_hook(int status) {
   return __lsan::ExitHook(status);
 }
 
 #endif

compiler-rt/lib/sanitizer_common/sanitizer_stoptheworld_fuchsia.cpp

 #if SANITIZER_FUCHSIA
 
 #include <zircon/sanitizer.h>
 
 #include "sanitizer_stoptheworld.h"
 
 namespace __sanitizer {
 
+namespace {
+
+// Fuchsia does not need a threadslist. This class only exists to pass a dummy
+// threadslist to pass to the StopTheWorldCallback since SuspendedThreadsList
+// has a protected destructor.
+class DummySuspendedThreadsListFuchsia final : public SuspendedThreadsList {
+ public:
+  ~DummySuspendedThreadsListFuchsia(){}
+};
+
+}
+
 // The Fuchsia implementation stops the world but doesn't offer a real
 // SuspendedThreadsList argument.  This is enough for ASan's use case,
 // and LSan does not use this API on Fuchsia.
 void StopTheWorld(StopTheWorldCallback callback, void *argument) {
   struct Params {
     StopTheWorldCallback callback;
     void *argument;
   } params = {callback, argument};
   __sanitizer_memory_snapshot(
       nullptr, nullptr, nullptr, nullptr,
       [](zx_status_t, void *data) {
         auto params = reinterpret_cast<Params *>(data);
-        params->callback({}, params->argument);
+        DummySuspendedThreadsListFuchsia threadlist;
+        params->callback(threadlist, params->argument);
       },
       &params);
 }
 
 }  // namespace __sanitizer
 
 #endif  // SANITIZER_FUCHSIA