use global-dynamic tls model for apache2handler

Author: henderkes

TSRM/TSRM.c

@@ -823,7 +823,10 @@ TSRM_API void *tsrm_get_ls_cache(void)
 /* Returns offset of tsrm_ls_cache slot from Thread Control Block address */
 TSRM_API size_t tsrm_get_ls_cache_tcb_offset(void)
 {/*{{{*/
-#if defined(__APPLE__) && defined(__x86_64__)
+#if defined(TSRM_TLS_MODEL_GLOBAL_DYNAMIC)
+	/* No constant TCB offset under global-dynamic, can't use fast path */
+	return 0;
+#elif defined(__APPLE__) && defined(__x86_64__)
     // TODO: Implement support for fast JIT ZTS code ???
 	return 0;
 #elif defined(__x86_64__) && defined(__GNUC__) && !defined(__FreeBSD__) && \

TSRM/TSRM.h

@@ -158,8 +158,13 @@ TSRM_API bool tsrm_is_managed_thread(void);
 # define TSRM_TLS_MODEL_ATTR
 # define TSRM_TLS_MODEL_DEFAULT
 #elif __PIC__ && !defined(__PIE__)
-# define TSRM_TLS_MODEL_ATTR __attribute__((tls_model("initial-exec")))
-# define TSRM_TLS_MODEL_INITIAL_EXEC
+# if defined(TSRM_TLS_MODEL_USE_GLOBAL_DYNAMIC)
+#  define TSRM_TLS_MODEL_ATTR __attribute__((tls_model("global-dynamic")))
+#  define TSRM_TLS_MODEL_GLOBAL_DYNAMIC
+# else
+#  define TSRM_TLS_MODEL_ATTR __attribute__((tls_model("initial-exec")))
+#  define TSRM_TLS_MODEL_INITIAL_EXEC
+# endif
 #else
 # define TSRM_TLS_MODEL_ATTR __attribute__((tls_model("local-exec")))
 # define TSRM_TLS_MODEL_LOCAL_EXEC

sapi/apache2handler/config.m4

@@ -85,6 +85,10 @@ if test "$PHP_APXS2" != "no"; then
   LIBPHP_CFLAGS="-shared"
   PHP_SUBST([LIBPHP_CFLAGS])
 
+  dnl httpd dlopen's libphp.so without linking against it, so _tsrm_ls_cache can't
+  dnl use initial-exec (overflows the static TLS surplus)
+  AS_VAR_APPEND([CFLAGS], [" -DTSRM_TLS_MODEL_USE_GLOBAL_DYNAMIC"])
+
   php_sapi_apache2handler_type=shared
   AS_CASE([$host_alias],
     [*aix*], [