Bug 1102525 (part 1) - Add InfallibleAllocPolicy to mozalloc. r=glandium.

--HG--
extra : rebase_source : a79162fb7f73e52c5c8df29c8229efc64c3451e5

memory/mozalloc/mozalloc.h

@@ -21,6 +21,8 @@
 
 #if defined(__cplusplus)
 #include "mozilla/fallible.h"
+#include "mozilla/NullPtr.h"
+#include "mozilla/TemplateLib.h"
 #endif
 #include "mozilla/Attributes.h"
 
@@ -294,7 +296,49 @@ void operator delete[](void* ptr, const mozilla::fallible_t&) MOZALLOC_THROW_IF_
     moz_free(ptr);
 }
 
+
+/*
+ * This policy is identical to MallocAllocPolicy, except it uses
+ * moz_xmalloc/moz_xcalloc/moz_xrealloc/moz_free instead of
+ * malloc/calloc/realloc/free.
+ */
+class InfallibleAllocPolicy
+{
+public:
+    template <typename T>
+    T* pod_malloc(size_t aNumElems)
+    {
+        if (aNumElems & mozilla::tl::MulOverflowMask<sizeof(T)>::value) {
+            return nullptr;
+        }
+        return static_cast<T*>(moz_xmalloc(aNumElems * sizeof(T)));
+    }
+
+    template <typename T>
+    T* pod_calloc(size_t aNumElems)
+    {
+        return static_cast<T*>(moz_xcalloc(aNumElems, sizeof(T)));
+    }
+
+    template <typename T>
+    T* pod_realloc(T* aPtr, size_t aOldSize, size_t aNewSize)
+    {
+        if (aNewSize & mozilla::tl::MulOverflowMask<sizeof(T)>::value) {
+            return nullptr;
+        }
+        return static_cast<T*>(moz_xrealloc(aPtr, aNewSize * sizeof(T)));
+    }
+
+    void free_(void* aPtr)
+    {
+        moz_free(aPtr);
+    }
+
+    void reportAllocOverflow() const
+    {
+    }
+};
+
 #endif  /* ifdef __cplusplus */
 
-
 #endif /* ifndef mozilla_mozalloc_h */

memory/replace/dmd/DMD.cpp

@@ -111,12 +111,18 @@ static bool gIsDMDInitialized = false;
 
 // This provides infallible allocations (they abort on OOM).  We use it for all
 // of DMD's own allocations, which fall into the following three cases.
+//
 // - Direct allocations (the easy case).
+//
 // - Indirect allocations in js::{Vector,HashSet,HashMap} -- this class serves
 //   as their AllocPolicy.
+//
 // - Other indirect allocations (e.g. NS_StackWalk) -- see the comments on
 //   Thread::mBlockIntercepts and in replace_malloc for how these work.
 //
+// It would be nice if we could use the InfallibleAllocPolicy from mozalloc,
+// but DMD cannot use mozalloc.
+//
 class InfallibleAllocPolicy
 {
   static void ExitOnFailure(const void* aP);

mfbt/AllocPolicy.h

@@ -55,8 +55,9 @@ public:
   template <typename T>
   T* pod_malloc(size_t aNumElems)
   {
-    if (aNumElems & mozilla::tl::MulOverflowMask<sizeof(T)>::value)
-        return nullptr;
+    if (aNumElems & mozilla::tl::MulOverflowMask<sizeof(T)>::value) {
+      return nullptr;
+    }
     return static_cast<T*>(malloc(aNumElems * sizeof(T)));
   }
 
@@ -69,8 +70,9 @@ public:
   template <typename T>
   T* pod_realloc(T* aPtr, size_t aOldSize, size_t aNewSize)
   {
-    if (aNewSize & mozilla::tl::MulOverflowMask<sizeof(T)>::value)
-        return nullptr;
+    if (aNewSize & mozilla::tl::MulOverflowMask<sizeof(T)>::value) {
+      return nullptr;
+    }
     return static_cast<T*>(realloc(aPtr, aNewSize * sizeof(T)));
   }