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commit 6f863d55e907da4b6c612941a8939dad9f9840e0
parent 649b1ba949341625ce7d2faf57c032d89356f377
Author: Paul Bone <paul@bone.id.au>
Date:   Thu, 16 Oct 2025 22:26:50 +0000

Bug 1984011 - pt 7. Add assertions to Mutex's initialisation r=glandium

Differential Revision: https://phabricator.services.mozilla.com/D262273

Diffstat:
M
memory/build/Mutex.cpp
 | 
2
++
M
memory/build/Mutex.h
 | 
21
+++++++++++++++++++--

2 files changed, 21 insertions(+), 2 deletions(-)
diff --git a/memory/build/Mutex.cpp b/memory/build/Mutex.cpp
@@ -9,6 +9,8 @@
 #include "mozilla/Assertions.h"
 
 bool Mutex::TryLock() {
+  MOZ_ASSERT(mInitialised);
+
 #if defined(XP_WIN)
   return !!TryEnterCriticalSection(mMutex.addr());
 #elif defined(XP_DARWIN)
diff --git a/memory/build/Mutex.h b/memory/build/Mutex.h
@@ -58,12 +58,24 @@ struct MOZ_CAPABILITY("mutex") Mutex {
   pthread_mutex_t mMutex = PTHREAD_MUTEX_INITIALIZER;
 #endif
 
+#ifdef MOZ_DEBUG
+  bool mInitialised = false;
+
+  // Called by StaticMutex
+  explicit constexpr Mutex(bool aInitialised) : mInitialised(aInitialised) {}
+#else
+  explicit constexpr Mutex(bool aIgnored) {}
+#endif
+
   // Although a constexpr constructor is provided, it will not initialise the
   // mutex and calling Init() is required.
   constexpr Mutex() {}
 
   // (Re-)initializes a mutex. Returns whether initialization succeeded.
   inline bool Init() {
+#ifdef MOZ_DEBUG
+    mInitialised = true;
+#endif
 #if defined(XP_WIN)
     if (!InitializeCriticalSectionAndSpinCount(mMutex.addr(), 5000)) {
       return false;
@@ -90,6 +102,8 @@ struct MOZ_CAPABILITY("mutex") Mutex {
   }
 
   inline void Lock() MOZ_CAPABILITY_ACQUIRE() {
+    MOZ_ASSERT(mInitialised);
+
 #if defined(XP_WIN)
     EnterCriticalSection(mMutex.addr());
 #elif defined(XP_DARWIN)
@@ -111,6 +125,8 @@ struct MOZ_CAPABILITY("mutex") Mutex {
   [[nodiscard]] bool TryLock() MOZ_TRY_ACQUIRE(true);
 
   inline void Unlock() MOZ_CAPABILITY_RELEASE() {
+    MOZ_ASSERT(mInitialised);
+
 #if defined(XP_WIN)
     LeaveCriticalSection(mMutex.addr());
 #elif defined(XP_DARWIN)
@@ -149,8 +165,9 @@ struct MOZ_CAPABILITY("mutex") StaticMutex {
 };
 
 #else
-typedef Mutex StaticMutex;
-
+struct MOZ_CAPABILITY("mutex") StaticMutex : public Mutex {
+  constexpr StaticMutex() : Mutex(true) {}
+};
 #endif
 
 #ifdef XP_WIN