[llvm] [OFFLOAD] Add support for indexed per-thread containers (PR #164263)

[Alex Duran via llvm-commits]

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@@ -91,24 +177,114 @@ template <typename ContainerType, typename ObjectType> struct PerThreadTable {
   // Iterators to traverse objects owned by
   // the current thread
   iterator begin() {
-    auto &Entry = getThreadEntry();
+    ContainerType &Entry = getThreadEntry();
     return Entry.begin();
   }
   iterator end() {
-    auto &Entry = getThreadEntry();
+    ContainerType &Entry = getThreadEntry();
     return Entry.end();
   }
 
-  template <class F> void clear(F f) {
-    std::lock_guard<std::mutex> Lock(Mtx);
-    for (auto ThData : ThreadDataList) {
-      if (!ThData->ThEntry || ThData->NElements == 0)
+  template <class ClearFuncTy> void clear(ClearFuncTy ClearFunc) {
+    assert(Mutex.try_lock() && (Mutex.unlock(), true) &&
+           "Clear cannot be called while other threads are adding entries");
+    for (std::shared_ptr<PerThreadData> ThreadData : ThreadDataList) {
+      if (!ThreadData->ThreadEntry || ThreadData->NElements == 0)
         continue;
-      ThData->ThEntry->clear(f);
-      ThData->NElements = 0;
+      if constexpr (has_clearAll<ContainerType>::value) {
+        ThreadData->ThreadEntry->clearAll(ClearFunc);
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adurang wrote:

It's something used for non-STL containers but none are upstream right now. I'll remove it.

https://github.com/llvm/llvm-project/pull/164263