5 files changed, 27 insertions, 19 deletions
diff --git a/absl/base/internal/spinlock.cc b/absl/base/internal/spinlock.cc
index fd0c733e234b..7cac72f97f28 100644
--- a/absl/base/internal/spinlock.cc
+++ b/absl/base/internal/spinlock.cc
@@ -66,6 +66,13 @@ void RegisterSpinLockProfiler(void (*fn)(const void *contendedlock,
   submit_profile_data.Store(fn);
 }
 
+// Static member variable definitions.
+constexpr uint32_t SpinLock::kSpinLockHeld;
+constexpr uint32_t SpinLock::kSpinLockCooperative;
+constexpr uint32_t SpinLock::kSpinLockDisabledScheduling;
+constexpr uint32_t SpinLock::kSpinLockSleeper;
+constexpr uint32_t SpinLock::kWaitTimeMask;
+
 // Uncommon constructors.
 SpinLock::SpinLock(base_internal::SchedulingMode mode)
     : lockword_(IsCooperative(mode) ? kSpinLockCooperative : 0) {
diff --git a/absl/base/internal/spinlock.h b/absl/base/internal/spinlock.h
index 89e93aad0bd0..2b08a2d6e2f1 100644
--- a/absl/base/internal/spinlock.h
+++ b/absl/base/internal/spinlock.h
@@ -36,6 +36,7 @@
 #include <atomic>
 
 #include "absl/base/attributes.h"
+#include "absl/base/const_init.h"
 #include "absl/base/dynamic_annotations.h"
 #include "absl/base/internal/low_level_scheduling.h"
 #include "absl/base/internal/raw_logging.h"
@@ -77,6 +78,10 @@ class ABSL_LOCKABLE SpinLock {
   SpinLock(base_internal::LinkerInitialized,
            base_internal::SchedulingMode mode);
 
+  // Constructor for global SpinLock instances.  See absl/base/const_init.h.
+  constexpr SpinLock(absl::ConstInitType, base_internal::SchedulingMode mode)
+      : lockword_(IsCooperative(mode) ? kSpinLockCooperative : 0) {}
+
   ~SpinLock() { ABSL_TSAN_MUTEX_DESTROY(this, __tsan_mutex_not_static); }
 
   // Acquire this SpinLock.
diff --git a/absl/base/internal/sysinfo.cc b/absl/base/internal/sysinfo.cc
index c3f275ca8a28..6c69683faf67 100644
--- a/absl/base/internal/sysinfo.cc
+++ b/absl/base/internal/sysinfo.cc
@@ -344,15 +344,16 @@ pid_t GetTID() {
 #else
 
 // Fallback implementation of GetTID using pthread_getspecific.
-static once_flag tid_once;
-static pthread_key_t tid_key;
-static absl::base_internal::SpinLock tid_lock(
-    absl::base_internal::kLinkerInitialized);
+ABSL_CONST_INIT static once_flag tid_once;
+ABSL_CONST_INIT static pthread_key_t tid_key;
+ABSL_CONST_INIT static absl::base_internal::SpinLock tid_lock(
+    absl::kConstInit, base_internal::SCHEDULE_KERNEL_ONLY);
 
 // We set a bit per thread in this array to indicate that an ID is in
 // use. ID 0 is unused because it is the default value returned by
 // pthread_getspecific().
-static std::vector<uint32_t>* tid_array ABSL_GUARDED_BY(tid_lock) = nullptr;
+ABSL_CONST_INIT static std::vector<uint32_t> *tid_array
+    ABSL_GUARDED_BY(tid_lock) = nullptr;
 static constexpr int kBitsPerWord = 32;  // tid_array is uint32_t.
 
 // Returns the TID to tid_array.
diff --git a/absl/base/internal/thread_identity_test.cc b/absl/base/internal/thread_identity_test.cc
index 3685779ce8f5..624d5b96b6ee 100644
--- a/absl/base/internal/thread_identity_test.cc
+++ b/absl/base/internal/thread_identity_test.cc
@@ -21,6 +21,7 @@
 #include "absl/base/attributes.h"
 #include "absl/base/internal/spinlock.h"
 #include "absl/base/macros.h"
+#include "absl/base/thread_annotations.h"
 #include "absl/synchronization/internal/per_thread_sem.h"
 #include "absl/synchronization/mutex.h"
 
@@ -29,10 +30,9 @@ ABSL_NAMESPACE_BEGIN
 namespace base_internal {
 namespace {
 
-// protects num_identities_reused
-static absl::base_internal::SpinLock map_lock(
-    absl::base_internal::kLinkerInitialized);
-static int num_identities_reused;
+ABSL_CONST_INIT static absl::base_internal::SpinLock map_lock(
+    absl::kConstInit, base_internal::SCHEDULE_KERNEL_ONLY);
+ABSL_CONST_INIT static int num_identities_reused ABSL_GUARDED_BY(map_lock);
 
 static const void* const kCheckNoIdentity = reinterpret_cast<void*>(1);
 
@@ -90,6 +90,7 @@ TEST(ThreadIdentityTest, BasicIdentityWorksThreaded) {
   // We should have recycled ThreadIdentity objects above; while (external)
   // library threads allocating their own identities may preclude some
   // reuse, we should have sufficient repetitions to exclude this.
+  absl::base_internal::SpinLockHolder l(&map_lock);
   EXPECT_LT(kNumThreads, num_identities_reused);
 }
 
diff --git a/absl/base/spinlock_test_common.cc b/absl/base/spinlock_test_common.cc
index 08f61ba86a38..b68c51a1dcde 100644
--- a/absl/base/spinlock_test_common.cc
+++ b/absl/base/spinlock_test_common.cc
@@ -56,12 +56,10 @@ namespace {
 static constexpr int kArrayLength = 10;
 static uint32_t values[kArrayLength];
 
-static SpinLock static_spinlock(base_internal::kLinkerInitialized);
-static SpinLock static_cooperative_spinlock(
-    base_internal::kLinkerInitialized,
-    base_internal::SCHEDULE_COOPERATIVE_AND_KERNEL);
-static SpinLock static_noncooperative_spinlock(
-    base_internal::kLinkerInitialized, base_internal::SCHEDULE_KERNEL_ONLY);
+ABSL_CONST_INIT static SpinLock static_cooperative_spinlock(
+    absl::kConstInit, base_internal::SCHEDULE_COOPERATIVE_AND_KERNEL);
+ABSL_CONST_INIT static SpinLock static_noncooperative_spinlock(
+    absl::kConstInit, base_internal::SCHEDULE_KERNEL_ONLY);
 
 // Simple integer hash function based on the public domain lookup2 hash.
 // http://burtleburtle.net/bob/c/lookup2.c
@@ -191,10 +189,6 @@ TEST(SpinLock, WaitCyclesEncoding) {
   EXPECT_GT(expected_max_value_decoded, before_max_value_decoded);
 }
 
-TEST(SpinLockWithThreads, StaticSpinLock) {
-  ThreadedTest(&static_spinlock);
-}
-
 TEST(SpinLockWithThreads, StackSpinLock) {
   SpinLock spinlock;
   ThreadedTest(&spinlock);