Fix GH-14551: PGO build fails with xxhash

Turns out that the instrumentation added for gcov can change inlining
decisions of the compiler, which results in a mismatch between the
profile data CFG and the actual generated CFG between compiles.

There are two functions that suffer from this issue:
1. _PHP_XXH3_Init: Removing the inline hint fixes this one. In fact,
   always inlining this makes no sense as there's no real opportunity
   for specialising. It just bloats the binary and increases I$ pressure.
   So besides fixing this issue it's beneficial on its own to drop the
   attribute.
2. PHP_XXH3_128_Final: Sometimes XXH128_canonicalFromHash gets inlined
   and sometimes not. Make sure it gets always inlined.

Closes GH-18814.

Author: ndossche

NEWS

@@ -18,6 +18,9 @@ PHP                                                                        NEWS
 - FPM:
   . Fixed GH-18662 (fpm_get_status segfault). (txuna)
 
+- Hash:
+  . Fixed bug GH-14551 (PGO build fails with xxhash). (nielsdos)
+
 - Intl:
   . Fix memory leak in intl_datetime_decompose() on failure. (nielsdos)
   . Fix memory leak in locale lookup on failure. (nielsdos)

ext/hash/hash_xxhash.c

@@ -154,7 +154,7 @@ const php_hash_ops php_hash_xxh3_64_ops = {
 typedef XXH_errorcode (*xxh3_reset_with_secret_func_t)(XXH3_state_t*, const void*, size_t);
 typedef XXH_errorcode (*xxh3_reset_with_seed_func_t)(XXH3_state_t*, XXH64_hash_t);
 
-zend_always_inline static void _PHP_XXH3_Init(PHP_XXH3_64_CTX *ctx, HashTable *args,
+static void _PHP_XXH3_Init(PHP_XXH3_64_CTX *ctx, HashTable *args,
 		xxh3_reset_with_seed_func_t func_init_seed, xxh3_reset_with_secret_func_t func_init_secret, const char* algo_name)
 {
 	memset(&ctx->s, 0, sizeof ctx->s);

ext/hash/xxhash/xxhash.h

@@ -931,7 +931,7 @@ XXH_PUBLIC_API int XXH128_cmp(const void* h128_1, const void* h128_2);
 
 /*******   Canonical representation   *******/
 typedef struct { unsigned char digest[sizeof(XXH128_hash_t)]; } XXH128_canonical_t;
-XXH_PUBLIC_API void XXH128_canonicalFromHash(XXH128_canonical_t* dst, XXH128_hash_t hash);
+static zend_always_inline void XXH128_canonicalFromHash(XXH128_canonical_t* dst, XXH128_hash_t hash);
 XXH_PUBLIC_API XXH128_hash_t XXH128_hashFromCanonical(const XXH128_canonical_t* src);
 
 
@@ -5503,7 +5503,7 @@ XXH_PUBLIC_API int XXH128_cmp(const void* h128_1, const void* h128_2)
 
 /*======   Canonical representation   ======*/
 /*! @ingroup xxh3_family */
-XXH_PUBLIC_API void
+static zend_always_inline void
 XXH128_canonicalFromHash(XXH128_canonical_t* dst, XXH128_hash_t hash)
 {
     XXH_STATIC_ASSERT(sizeof(XXH128_canonical_t) == sizeof(XXH128_hash_t));