refactor wraprec storage and lookup [wip]

Implement wraprec lookup by scope and function name. The implementation uses
two specialized hashmaps: one for global functions and another one for scopes.
The scopes hashmap's values are hashmaps for scoped methods. The hashmaps use
keys composed of not only the string and its length but also zend string's
hash. This hash is used to find the bucket index. The decision to include zend
string's hash was deliberate because the agent gets it for free when it needs
to lookup the wraprec based on scope and function name that are available in
execute_data's op array as zend_strings.

Author: lavarou

agent/Makefile.frag

@@ -117,6 +117,7 @@ TEST_BINARIES = \
 	tests/test_txn_private \
 	tests/test_user_instrument \
 	tests/test_user_instrument_hashmap \
+	tests/test_user_instrument_wraprec_hashmap \
 	tests/test_zval
 
 .PHONY: unit-tests

agent/config.m4

@@ -220,6 +220,7 @@ if test "$PHP_NEWRELIC" = "yes"; then
   php_pdo_mysql.c php_pdo_pgsql.c php_pgsql.c php_psr7.c php_redis.c \
   php_rinit.c php_rshutdown.c php_samplers.c php_stack.c \
   php_stacked_segment.c php_txn.c php_user_instrument.c \
+  php_user_instrument_wraprec_hashmap.c \
   php_user_instrument_hashmap.c php_vm.c php_wrapper.c"
   FRAMEWORKS="fw_cakephp.c fw_codeigniter.c fw_drupal8.c \
   fw_drupal.c fw_drupal_common.c fw_joomla.c fw_kohana.c \

agent/php_user_instrument.c

@@ -175,7 +175,6 @@ void nr_php_init_user_instrumentation(void) {
  * wrapped). This happens because with new request/transaction php is loading
  * all new user code.
  */
-static void nr_php_user_wraprec_destroy(nruserfn_t** wraprec_ptr);
 static void reset_wraprec(nruserfn_t* wraprec) {
   nruserfn_t* p = wraprec;
   nr_php_wraprec_hashmap_key_release(&p->key);
@@ -301,7 +300,7 @@ static void nr_php_wrap_user_function_internal(nruserfn_t* wraprec TSRMLS_DC) {
   nr_php_wrap_zend_function(orig_func, wraprec TSRMLS_CC);
 }
 
-static nruserfn_t* nr_php_user_wraprec_create(void) {
+nruserfn_t* nr_php_user_wraprec_create(void) {
   nruserfn_t* wr = (nruserfn_t*)nr_zalloc(sizeof(nruserfn_t));
   wr->pid = NRPRG(pid);
   return wr;
@@ -357,7 +356,7 @@ static nruserfn_t* nr_php_user_wraprec_create_named(const char* full_name,
   return wraprec;
 }
 
-static void nr_php_user_wraprec_destroy(nruserfn_t** wraprec_ptr) {
+void nr_php_user_wraprec_destroy(nruserfn_t** wraprec_ptr) {
   nruserfn_t* wraprec;
 
   if (0 == wraprec_ptr) {

agent/php_user_instrument.h

@@ -218,6 +218,8 @@ extern int nr_zend_call_oapi_special_clean(nruserfn_t* wraprec,
                                            nr_segment_t* segment,
                                            NR_EXECUTE_PROTO);
 #endif
+extern nruserfn_t* nr_php_user_wraprec_create(void);
+extern void nr_php_user_wraprec_destroy(nruserfn_t** wraprec_ptr);
 /*
  * Purpose : Destroy all user instrumentation records, freeing
  *           associated memory.