Merge pull request #4679 from wilzbach/allocator_safe_1

Add attributes to GCAllocator and theAllocator

std/experimental/allocator/gc_allocator.d

@@ -21,7 +21,7 @@ struct GCAllocator
     deallocate) and $(D reallocate) methods are $(D @system) because they may
     move memory around, leaving dangling pointers in user code.
     */
-    @trusted void[] allocate(size_t bytes) shared
+    pure nothrow @trusted void[] allocate(size_t bytes) shared
     {
         if (!bytes) return null;
         auto p = GC.malloc(bytes);
@@ -52,7 +52,7 @@ struct GCAllocator
     }
 
     /// Ditto
-    @system bool reallocate(ref void[] b, size_t newSize) shared
+    pure nothrow @system bool reallocate(ref void[] b, size_t newSize) shared
     {
         import core.exception : OutOfMemoryError;
         try
@@ -69,15 +69,15 @@ struct GCAllocator
     }
 
     /// Ditto
-    void[] resolveInternalPointer(void* p) shared
+    pure nothrow void[] resolveInternalPointer(void* p) shared
     {
         auto r = GC.addrOf(p);
         if (!r) return null;
         return r[0 .. GC.sizeOf(r)];
     }
 
     /// Ditto
-    @system bool deallocate(void[] b) shared
+    pure nothrow @system bool deallocate(void[] b) shared
     {
         GC.free(b.ptr);
         return true;
@@ -110,7 +110,7 @@ struct GCAllocator
     static shared GCAllocator instance;
 
     // Leave it undocummented for now.
-    @trusted void collect() shared
+    nothrow @trusted void collect() shared
     {
         GC.collect();
     }

std/experimental/allocator/package.d

@@ -358,13 +358,13 @@ to be shared across threads, use $(D processAllocator) (below). By default,
 $(D theAllocator) ultimately fetches memory from $(D processAllocator), which
 in turn uses the garbage collected heap.
 */
-@property IAllocator theAllocator()
+nothrow @safe @nogc @property IAllocator theAllocator()
 {
     return _threadAllocator;
 }
 
 /// Ditto
-@property void theAllocator(IAllocator a)
+nothrow @safe @nogc @property void theAllocator(IAllocator a)
 {
     assert(a);
     _threadAllocator = a;