[PATCH 3/4] ntdll: Iterate TEBs only once in alloc_tls_slot().

[Paul Gofman]

From: Paul Gofman

---
 dlls/ntdll/loader.c | 26 ++++++++++++--------------
 1 file changed, 12 insertions(+), 14 deletions(-)

diff --git a/dlls/ntdll/loader.c b/dlls/ntdll/loader.c
index ebdb08569c0..5d0f03a76da 100644
--- a/dlls/ntdll/loader.c
+++ b/dlls/ntdll/loader.c
@@ -1294,6 +1294,7 @@ static BOOL alloc_tls_slot( LDR_DATA_TABLE_ENTRY *mod )
     ULONG i, size;
     void *new_ptr;
     LIST_ENTRY *entry;
+    UINT old_module_count = tls_module_count;

if (!(dir = RtlImageDirectoryEntryToData( mod->DllBase, TRUE, IMAGE_DIRECTORY_ENTRY_TLS, &size )))
         return FALSE;
@@ -1319,16 +1320,22 @@ static BOOL alloc_tls_slot( LDR_DATA_TABLE_ENTRY *mod )
         new_ptr = RtlReAllocateHeap( GetProcessHeap(), HEAP_ZERO_MEMORY, tls_dirs,
                                      new_count * sizeof(*tls_dirs) );
         if (!new_ptr) return FALSE;
+        tls_dirs = new_ptr;
+        tls_module_count = new_count;
+    }

-        /* resize the pointer block in all running threads */
-        for (entry = tls_links.Flink; entry != &tls_links; entry = entry->Flink)
+    /* allocate the data block in all running threads */
+    for (entry = tls_links.Flink; entry != &tls_links; entry = entry->Flink)
+    {
+        TEB *teb = CONTAINING_RECORD( entry, TEB, TlsLinks );
+
+        if (old_module_count < tls_module_count)
         {
-            TEB *teb = CONTAINING_RECORD( entry, TEB, TlsLinks );
             void **old = teb->ThreadLocalStoragePointer;
-            void **new = RtlAllocateHeap( GetProcessHeap(), HEAP_ZERO_MEMORY, new_count * sizeof(*new));
+            void **new = RtlAllocateHeap( GetProcessHeap(), HEAP_ZERO_MEMORY, tls_module_count * sizeof(*new));

if (!new) return FALSE;
-            if (old) memcpy( new, old, tls_module_count * sizeof(*new) );
+            if (old) memcpy( new, old, old_module_count * sizeof(*new) );
             teb->ThreadLocalStoragePointer = new;
 #ifdef __x86_64__  /* macOS-specific hack */
             if (teb->Instrumentation[0]) ((TEB *)teb->Instrumentation[0])->ThreadLocalStoragePointer = new;
@@ -1337,15 +1344,6 @@ static BOOL alloc_tls_slot( LDR_DATA_TABLE_ENTRY *mod )
             /* FIXME: can't free old block here, should be freed at thread exit */
         }

-        tls_dirs = new_ptr;
-        tls_module_count = new_count;
-    }
-
-    /* allocate the data block in all running threads */
-    for (entry = tls_links.Flink; entry != &tls_links; entry = entry->Flink)
-    {
-        TEB *teb = CONTAINING_RECORD( entry, TEB, TlsLinks );
-
         if (!(new_ptr = RtlAllocateHeap( GetProcessHeap(), 0, size + dir->SizeOfZeroFill ))) return -1;
         memcpy( new_ptr, (void *)dir->StartAddressOfRawData, size );
         memset( (char *)new_ptr + size, 0, dir->SizeOfZeroFill );