[glib/glib-2-60: 1/2] ghash: Disable small-arrays under valgrind

[Philip Withnall <pwithnall src gnome org>]

commit 75f8ec1df9b48b0c3a13a9125f2c7d7c5adf5159
Author: Allison Karlitskaya <allison karlitskaya redhat com>
Date:   Tue May 14 09:49:56 2019 +0200

    ghash: Disable small-arrays under valgrind
    
    Valgrind can't find 64bit pointers when we pack them into an array of
    32bit values.  Disable this optimisation if we detect that we are
    running under valgrind.
    
    Fixes #1749

 glib/ghash.c | 22 +++++++++++++++++-----
 1 file changed, 17 insertions(+), 5 deletions(-)
---
diff --git a/glib/ghash.c b/glib/ghash.c
index dac5552bd..c58e8c585 100644
--- a/glib/ghash.c
+++ b/glib/ghash.c
@@ -38,6 +38,7 @@
 #include "gtestutils.h"
 #include "gslice.h"
 #include "grefcount.h"
+#include "gvalgrind.h"
 
 /* The following #pragma is here so we can do this...
  *
@@ -1014,6 +1015,7 @@ g_hash_table_new_full (GHashFunc      hash_func,
                        GDestroyNotify value_destroy_func)
 {
   GHashTable *hash_table;
+  gboolean small;
 
   hash_table = g_slice_new (GHashTable);
   g_hash_table_set_shift (hash_table, HASH_TABLE_MIN_SHIFT);
@@ -1031,14 +1033,24 @@ g_hash_table_new_full (GHashFunc      hash_func,
   hash_table->values             = hash_table->keys;
   hash_table->hashes             = g_new0 (guint, hash_table->size);
 
+  /* We want to use small arrays only if:
+   *   - we are running on a system where that makes sense (64 bit); and
+   *   - we are not running under valgrind.
+   */
+  small = FALSE;
+
 #ifdef USE_SMALL_ARRAYS
-  hash_table->have_big_keys = FALSE;
-  hash_table->have_big_values = FALSE;
-#else
-  hash_table->have_big_keys = TRUE;
-  hash_table->have_big_values = TRUE;
+  small = TRUE;
+
+# ifdef ENABLE_VALGRIND
+  if (RUNNING_ON_VALGRIND)
+    small = FALSE;
+# endif
 #endif
 
+  hash_table->have_big_keys = !small;
+  hash_table->have_big_values = !small;
+
   return hash_table;
 }