Revert "Revert "Merge branch 'PHP-7.4'""

This reverts commit 28e650a, which reverted commit 046dcfb, which had
to be reverted due to phpdbg issues.  The culprit was that we did not
properly reset `zend_handler_table` to `NULL`, which is required for
SAPIs which may restart the engine after shutdown.

[1] <http://git.php.net/?p=php-src.git;a=commit;h=28e650abf8097a28789a005e5028fee095359583>
[2] <http://git.php.net/?p=php-src.git;a=commit;h=046dcfb531e242d36a7af2942b9b148290c3c7fe>

Author: cmb69

Zend/zend_portability.h

@@ -613,4 +613,12 @@ extern "C++" {
 # define ZEND_PREFER_RELOAD
 #endif
 
+#if defined(ZEND_WIN32) && defined(_DEBUG) && defined(PHP_WIN32_DEBUG_HEAP)
+# define ZEND_IGNORE_LEAKS_BEGIN() _CrtSetDbgFlag(_CrtSetDbgFlag(_CRTDBG_REPORT_FLAG) & ~_CRTDBG_ALLOC_MEM_DF)
+# define ZEND_IGNORE_LEAKS_END() _CrtSetDbgFlag(_CrtSetDbgFlag(_CRTDBG_REPORT_FLAG) | _CRTDBG_ALLOC_MEM_DF)
+#else
+# define ZEND_IGNORE_LEAKS_BEGIN()
+# define ZEND_IGNORE_LEAKS_END()
+#endif
+
 #endif /* ZEND_PORTABILITY_H */

Zend/zend_strtod.c

@@ -546,6 +546,7 @@ Bigint {
  static Bigint *freelist[Kmax+1];
 
 static void destroy_freelist(void);
+static void free_p5s(void);
 
 #ifdef ZTS
 static MUTEX_T dtoa_mutex;
@@ -564,6 +565,8 @@ ZEND_API int zend_startup_strtod(void) /* {{{ */
 ZEND_API int zend_shutdown_strtod(void) /* {{{ */
 {
 	destroy_freelist();
+	free_p5s();
+
 #ifdef ZTS
 	tsrm_mutex_free(dtoa_mutex);
 	dtoa_mutex = NULL;
@@ -4540,6 +4543,19 @@ static void destroy_freelist(void)
 	FREE_DTOA_LOCK(0)
 }
 
+static void free_p5s(void)
+{
+	Bigint **listp, *tmp;
+
+	ACQUIRE_DTOA_LOCK(1)
+	listp = &p5s;
+	while ((tmp = *listp) != NULL) {
+		*listp = tmp->next;
+		free(tmp);
+	}
+	FREE_DTOA_LOCK(1)
+}
+
 #ifdef __cplusplus
 }
 #endif

Zend/zend_vm_execute.h

@@ -59579,13 +59579,18 @@ void zend_vm_init(void)
 	VM_TRACE_START();
 }
 
+static HashTable *zend_handlers_table = NULL;
+
 void zend_vm_dtor(void)
 {
 	VM_TRACE_END();
+	if (zend_handlers_table) {
+		zend_hash_destroy(zend_handlers_table);
+		free(zend_handlers_table);
+		zend_handlers_table = NULL;
+	}
 }
 
-static HashTable *zend_handlers_table = NULL;
-
 static void init_opcode_serialiser(void)
 {
 	int i;

Zend/zend_vm_execute.skl

@@ -67,13 +67,18 @@ void {%INITIALIZER_NAME%}(void)
 	VM_TRACE_START();
 }
 
+static HashTable *zend_handlers_table = NULL;
+
 void zend_vm_dtor(void)
 {
 	VM_TRACE_END();
+	if (zend_handlers_table) {
+		zend_hash_destroy(zend_handlers_table);
+		free(zend_handlers_table);
+		zend_handlers_table = NULL;
+	}
 }
 
-static HashTable *zend_handlers_table = NULL;
-
 static void init_opcode_serialiser(void)
 {
 	int i;

ext/libxml/config.w32

@@ -16,6 +16,9 @@ if (PHP_LIBXML == "yes") {
 			ADD_DEF_FILE("ext\\libxml\\php_libxml2.def");
 		}
 		PHP_INSTALL_HEADERS("ext/libxml/", "php_libxml.h");
+		if (PHP_CRT_DEBUG == "yes") {
+			ADD_FLAG("CFLAGS_LIBXML", "/D PHP_WIN32_DEBUG_HEAP");
+		}
 	} else {
 		WARNING("libxml support can't be enabled, iconv or libxml are missing")
 		PHP_LIBXML = "no"

ext/libxml/libxml.c

@@ -700,7 +700,9 @@ PHP_LIBXML_API void php_libxml_initialize(void)
 {
 	if (!_php_libxml_initialized) {
 		/* we should be the only one's to ever init!! */
+		ZEND_IGNORE_LEAKS_BEGIN();
 		xmlInitParser();
+		ZEND_IGNORE_LEAKS_END();
 
 		_php_libxml_default_entity_loader = xmlGetExternalEntityLoader();
 		xmlSetExternalEntityLoader(_php_libxml_pre_ext_ent_loader);