Bug 773014 - Part 2: Mark Static{Auto,Ref}Ptr as global-only; r=jrmuizel

image/src/imgLoader.cpp

@@ -1031,7 +1031,7 @@ imgLoader::imgLoader()
 already_AddRefed<imgLoader>
 imgLoader::GetInstance()
 {
-  static StaticRefPtr<imgLoader> singleton;
+  static nsRefPtr<imgLoader> singleton;
   if (!singleton) {
     singleton = imgLoader::Create();
     if (!singleton)

mfbt/Attributes.h

@@ -495,6 +495,10 @@
  *   class uses this class, or if another class inherits from this class, then
  *   it is considered to be a non-heap class as well, although this attribute
  *   need not be provided in such cases.
+ * MOZ_ONLY_USED_TO_AVOID_STATIC_CONSTRUCTORS: Applies to all classes that are
+ *   intended to prevent introducing static initializers.  This attribute
+ *   currently makes it a compile-time error to instantiate these classes
+ *   anywhere other than at the global scope, or as a static member of a class.
  * MOZ_HEAP_ALLOCATOR: Applies to any function. This indicates that the return
  *   value is allocated on the heap, and will as a result check such allocations
  *   during MOZ_STACK_CLASS and MOZ_NONHEAP_CLASS annotation checking.
@@ -509,6 +513,7 @@
 #  define MOZ_MUST_OVERRIDE __attribute__((annotate("moz_must_override")))
 #  define MOZ_STACK_CLASS __attribute__((annotate("moz_stack_class")))
 #  define MOZ_NONHEAP_CLASS __attribute__((annotate("moz_nonheap_class")))
+#  define MOZ_ONLY_USED_TO_AVOID_STATIC_CONSTRUCTORS __attribute__((annotate("moz_global_class")))
 #  define MOZ_IMPLICIT __attribute__((annotate("moz_implicit")))
 #  define MOZ_NO_ARITHMETIC_EXPR_IN_ARGUMENT __attribute__((annotate("moz_no_arith_expr_in_arg")))
 /*
@@ -525,6 +530,7 @@
 #  define MOZ_MUST_OVERRIDE /* nothing */
 #  define MOZ_STACK_CLASS /* nothing */
 #  define MOZ_NONHEAP_CLASS /* nothing */
+#  define MOZ_ONLY_USED_TO_AVOID_STATIC_CONSTRUCTORS /* nothing */
 #  define MOZ_IMPLICIT /* nothing */
 #  define MOZ_NO_ARITHMETIC_EXPR_IN_ARGUMENT /* nothing */
 #  define MOZ_HEAP_ALLOCATOR /* nothing */

xpcom/base/StaticPtr.h

@@ -8,6 +8,7 @@
 #define mozilla_StaticPtr_h
 
 #include "mozilla/Assertions.h"
+#include "mozilla/Attributes.h"
 #include "mozilla/NullPtr.h"
 
 namespace mozilla {
@@ -25,17 +26,16 @@ namespace mozilla {
  * upon destruction.
  *
  * Since the compiler guarantees that all global variables are initialized to
- * 0, these trivial constructors are safe, so long as you use
+ * 0, these trivial constructors are safe.  Since we rely on this, the clang
- * Static{Auto,Ref}Ptr as a global variable.  If you use Static{Auto,Ref}Ptr as
+ * plugin, run as part of our "static analysis" builds, makes it a compile-time
- * a stack variable or as a class instance variable, you will get what you
+ * error to use Static{Auto,Ref}Ptr as anything except a global variable.
- * deserve.
  *
  * Static{Auto,Ref}Ptr have a limited interface as compared to ns{Auto,Ref}Ptr;
  * this is intentional, since their range of acceptable uses is smaller.
  */
 
 template<class T>
-class StaticAutoPtr
+class MOZ_ONLY_USED_TO_AVOID_STATIC_CONSTRUCTORS StaticAutoPtr
 {
 public:
   // In debug builds, check that mRawPtr is initialized for us as we expect
@@ -87,7 +87,7 @@ private:
 };
 
 template<class T>
-class StaticRefPtr
+class MOZ_ONLY_USED_TO_AVOID_STATIC_CONSTRUCTORS StaticRefPtr
 {
 public:
   // In debug builds, check that mRawPtr is initialized for us as we expect