ntdll: HACK: Introduce WINE_HEAP_TOP_DOWN hack.

CW-Bug-Id: #24362

Author: Paul Gofman

dlls/ntdll/heap.c

@@ -330,6 +330,7 @@ C_ASSERT( HEAP_MIN_LARGE_BLOCK_SIZE <= HEAP_INITIAL_GROW_SIZE );
 
 BOOL delay_heap_free = FALSE;
 BOOL heap_zero_hack = FALSE;
+BOOL heap_top_down_hack = FALSE;
 
 static struct heap *process_heap;  /* main process heap */
 
@@ -971,6 +972,7 @@ static struct block *split_block( struct heap *heap, ULONG flags, struct block *
 
 static void *allocate_region( struct heap *heap, ULONG flags, SIZE_T *region_size, SIZE_T *commit_size )
 {
+    ULONG reserve_flags = MEM_RESERVE;
     void *addr = NULL;
     NTSTATUS status;
 
@@ -980,8 +982,10 @@ static void *allocate_region( struct heap *heap, ULONG flags, SIZE_T *region_siz
         return NULL;
     }
 
+    if (heap_top_down_hack) reserve_flags |= MEM_TOP_DOWN;
+
     /* allocate the memory block */
-    if ((status = NtAllocateVirtualMemory( NtCurrentProcess(), &addr, 0, region_size, MEM_RESERVE,
+    if ((status = NtAllocateVirtualMemory( NtCurrentProcess(), &addr, 0, region_size, reserve_flags,
                                            get_protection_type( flags ) )))
     {
         WARN( "Could not allocate %#Ix bytes, status %#lx\n", *region_size, status );

dlls/ntdll/loader.c

@@ -4651,6 +4651,11 @@ void loader_init( CONTEXT *context, void **entry )
             ERR( "Enabling heap zero hack.\n" );
             heap_zero_hack = TRUE;
         }
+        if (get_env( L"WINE_HEAP_TOP_DOWN", env_str, sizeof(env_str)) && env_str[0] == L'1')
+        {
+            ERR( "Enabling heap top down hack.\n" );
+            heap_top_down_hack = TRUE;
+        }
 
         peb->ProcessHeap        = RtlCreateHeap( heap_flags, NULL, 0, 0, NULL, NULL );
 

dlls/ntdll/ntdll_misc.h

@@ -49,6 +49,7 @@ extern UINT_PTR page_size;
 
 extern BOOL delay_heap_free;
 extern BOOL heap_zero_hack;
+extern BOOL heap_top_down_hack;
 
 /* exceptions */
 extern LONG call_vectored_handlers( EXCEPTION_RECORD *rec, CONTEXT *context );