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commit 201ebb959d5cd846ae13dd09999220ed58d6083b
parent 08a04985b81187efeddb2f2d6717d1da9defe73b
Author: Paul Bone <paul@bone.id.au>
Date:   Thu, 16 Oct 2025 22:26:49 +0000

Bug 1984011 - pt 3. Make StaticMutex's constructor constexpr r=glandium

Differential Revision: https://phabricator.services.mozilla.com/D262269

Diffstat:
M
memory/build/Mutex.h
 | 
24
++++++++++--------------
M
memory/build/mozjemalloc.cpp
 | 
2
+-

2 files changed, 11 insertions(+), 15 deletions(-)
diff --git a/memory/build/Mutex.h b/memory/build/Mutex.h
@@ -44,9 +44,15 @@ struct MOZ_CAPABILITY("mutex") Mutex {
 #if defined(XP_WIN)
   CRITICAL_SECTION mMutex;
 #elif defined(XP_DARWIN)
-  os_unfair_lock mMutex;
+  os_unfair_lock mMutex = OS_UNFAIR_LOCK_INIT;
+#elif defined(XP_LINUX) && !defined(ANDROID)
+  pthread_mutex_t mMutex = PTHREAD_ADAPTIVE_MUTEX_INITIALIZER_NP;
 #else
-  pthread_mutex_t mMutex;
+  pthread_mutex_t mMutex = PTHREAD_MUTEX_INITIALIZER;
+#endif
+
+#ifndef XP_WIN
+  constexpr Mutex() {}
 #endif
 
   // Initializes a mutex. Returns whether initialization succeeded.
@@ -124,6 +130,8 @@ struct MOZ_CAPABILITY("mutex") Mutex {
 struct MOZ_CAPABILITY("mutex") StaticMutex {
   SRWLOCK mMutex;
 
+  constexpr StaticMutex() : mMutex(SRWLOCK_INIT) {}
+
   inline void Lock() MOZ_CAPABILITY_ACQUIRE() {
     AcquireSRWLockExclusive(&mMutex);
   }
@@ -133,21 +141,9 @@ struct MOZ_CAPABILITY("mutex") StaticMutex {
   }
 };
 
-// Normally, we'd use a constexpr constructor, but MSVC likes to create
-// static initializers anyways.
-#  define STATIC_MUTEX_INIT SRWLOCK_INIT
-
 #else
 typedef Mutex StaticMutex;
 
-#  if defined(XP_DARWIN)
-#    define STATIC_MUTEX_INIT OS_UNFAIR_LOCK_INIT
-#  elif defined(XP_LINUX) && !defined(ANDROID)
-#    define STATIC_MUTEX_INIT PTHREAD_ADAPTIVE_MUTEX_INITIALIZER_NP
-#  else
-#    define STATIC_MUTEX_INIT PTHREAD_MUTEX_INITIALIZER
-#  endif
-
 #endif
 
 #ifdef XP_WIN
diff --git a/memory/build/mozjemalloc.cpp b/memory/build/mozjemalloc.cpp
@@ -216,7 +216,7 @@ static Atomic<bool, MemoryOrdering::Relaxed> malloc_initialized;
 #endif
 
 // This lock must be held while bootstrapping us.
-StaticMutex gInitLock MOZ_UNANNOTATED = {STATIC_MUTEX_INIT};
+MOZ_CONSTINIT StaticMutex gInitLock MOZ_UNANNOTATED;
 
 // ***************************************************************************
 // Statistics data structures.