BUG: Fix cache use regression

seberg · charris · commit e6598146f92c · 2025-05-23T10:09:59.000-06:00
numpygh-29006 got the branching wrong leaving the cache undefined on most GCC/clang, which means we wouldn't use it. Also move it up so that we can just remove the unused globals entirely.
diff --git a/numpy/_core/src/multiarray/alloc.c b/numpy/_core/src/multiarray/alloc.c
@@ -27,17 +27,30 @@
 #endif
 #endif
 
-#define NBUCKETS 1024 /* number of buckets for data*/
-#define NBUCKETS_DIM 16 /* number of buckets for dimensions/strides */
-#define NCACHE 7 /* number of cache entries per bucket */
+/* Do not enable the alloc cache if the GIL is disabled, or if ASAN or MSAN
+ * instrumentation is enabled. The cache makes ASAN use-after-free or MSAN
+ * use-of-uninitialized-memory warnings less useful. */
+#define USE_ALLOC_CACHE 1
+#ifdef Py_GIL_DISABLED
+# define USE_ALLOC_CACHE 0
+#elif defined(__has_feature)
+# if __has_feature(address_sanitizer) || __has_feature(memory_sanitizer)
+#  define USE_ALLOC_CACHE 0
+# endif
+#endif
+
+#if USE_ALLOC_CACHE
+# define NBUCKETS 1024 /* number of buckets for data*/
+# define NBUCKETS_DIM 16 /* number of buckets for dimensions/strides */
+# define NCACHE 7 /* number of cache entries per bucket */
 /* this structure fits neatly into a cacheline */
 typedef struct {
     npy_uintp available; /* number of cached pointers */
     void * ptrs[NCACHE];
 } cache_bucket;
 static cache_bucket datacache[NBUCKETS];
 static cache_bucket dimcache[NBUCKETS_DIM];
-
+#endif  /* USE_ALLOC_CACHE */
 
 /*
  * This function tells whether NumPy attempts to call `madvise` with
@@ -99,20 +112,6 @@ indicate_hugepages(void *p, size_t size) {
 }
 
 
-/* Do not enable the alloc cache if the GIL is disabled, or if ASAN or MSAN
- * instrumentation is enabled. The cache makes ASAN use-after-free or MSAN
- * use-of-uninitialized-memory warnings less useful. */
-#ifdef Py_GIL_DISABLED
-#define USE_ALLOC_CACHE 0
-#elif defined(__has_feature)
-# if __has_feature(address_sanitizer) || __has_feature(memory_sanitizer)
-# define USE_ALLOC_CACHE 0
-# endif
-#else
-#define USE_ALLOC_CACHE 1
-#endif
-
-
 /* as the cache is managed in global variables verify the GIL is held */
 
 /*
