Avoid using a thread_local in an inline function since this

causes issues on some platforms.

Fixes #1946

PiperOrigin-RevId: 827571630
Change-Id: I217acb5778fa1224422e4893cc71c896e2c795fa

Author: derekmauro

absl/container/internal/raw_hash_set.cc

@@ -131,6 +131,16 @@ inline void* PrevSlot(void* slot, size_t slot_size) {
 
 }  // namespace
 
+// Must be defined out-of-line to avoid MSVC error C2482 on some platforms,
+// which is caused by non-constexpr initialization.
+uint16_t HashtableSize::NextSeed() {
+  static_assert(PerTableSeed::kBitCount == 16);
+  thread_local uint16_t seed =
+      static_cast<uint16_t>(reinterpret_cast<uintptr_t>(&seed));
+  seed += uint16_t{0xad53};
+  return seed;
+}
+
 GenerationType* EmptyGeneration() {
   if (SwisstableGenerationsEnabled()) {
     constexpr size_t kNumEmptyGenerations = 1024;

absl/container/internal/raw_hash_set.h

@@ -461,15 +461,6 @@ class PerTableSeed {
   const uint16_t seed_;
 };
 
-// Returns next per-table seed.
-inline uint16_t NextSeed() {
-  static_assert(PerTableSeed::kBitCount == 16);
-  thread_local uint16_t seed =
-      static_cast<uint16_t>(reinterpret_cast<uintptr_t>(&seed));
-  seed += uint16_t{0xad53};
-  return seed;
-}
-
 // The size and also has additionally
 // 1) one bit that stores whether we have infoz.
 // 2) PerTableSeed::kBitCount bits for the seed.
@@ -517,6 +508,9 @@ class HashtableSize {
 
   void set_no_seed_for_testing() { data_ &= ~kSeedMask; }
 
+  // Returns next per-table seed.
+  static uint16_t NextSeed();
+
  private:
   void set_seed(uint16_t seed) {
     data_ = (data_ & ~kSeedMask) | (seed | PerTableSeed::kSignBit);

absl/container/internal/raw_hash_set_test.cc

@@ -2560,7 +2560,7 @@ std::vector<int> OrderOfIteration(const T& t) {
 // in seed.
 void GenerateIrrelevantSeeds(int cnt) {
   for (int i = cnt % 17; i > 0; --i) {
-    NextSeed();
+    HashtableSize::NextSeed();
   }
 }