ext/opcache/zend_shared_alloc: add zend_shared_alloc_copy()

Allows simplifying some code in zend_jit_trace.c.

Author: MaxKellermann

ext/opcache/jit/zend_jit_trace.c

@@ -7085,36 +7085,31 @@ static zend_jit_trace_stop zend_jit_compile_root_trace(zend_jit_trace_rec *trace
 			JIT_G(trigger) = orig_trigger;
 
 			if (handler) {
-				zend_jit_trace_exit_info *shared_exit_info = NULL;
-
 				t->exit_info = NULL;
 				if (t->exit_count) {
 					/* reallocate exit_info into shared memory */
-					shared_exit_info = (zend_jit_trace_exit_info*)zend_shared_alloc(
+					t->exit_info = (zend_jit_trace_exit_info*)zend_shared_alloc_copy(exit_info,
 						sizeof(zend_jit_trace_exit_info) * t->exit_count);
 
-					if (!shared_exit_info) {
+					if (!t->exit_info) {
 					    if (t->stack_map) {
 							efree(t->stack_map);
 						}
 						ret = ZEND_JIT_TRACE_STOP_NO_SHM;
 						goto exit;
 					}
-					memcpy(shared_exit_info, exit_info,
-						sizeof(zend_jit_trace_exit_info) * t->exit_count);
-					t->exit_info = shared_exit_info;
 				}
 
 			    if (t->stack_map_size) {
-					zend_jit_trace_stack *shared_stack_map = (zend_jit_trace_stack*)zend_shared_alloc(t->stack_map_size * sizeof(zend_jit_trace_stack));
+					zend_jit_trace_stack *shared_stack_map = (zend_jit_trace_stack*)zend_shared_alloc_copy(
+						t->stack_map,
+						t->stack_map_size * sizeof(zend_jit_trace_stack));
+					efree(t->stack_map);
+					t->stack_map = shared_stack_map;
 					if (!shared_stack_map) {
-						efree(t->stack_map);
 						ret = ZEND_JIT_TRACE_STOP_NO_SHM;
 						goto exit;
 					}
-					memcpy(shared_stack_map, t->stack_map, t->stack_map_size * sizeof(zend_jit_trace_stack));
-					efree(t->stack_map);
-					t->stack_map = shared_stack_map;
 			    }
 
 				t->exit_counters = ZEND_JIT_EXIT_COUNTERS;
@@ -7815,36 +7810,31 @@ static zend_jit_trace_stop zend_jit_compile_side_trace(zend_jit_trace_rec *trace
 			JIT_G(trigger) = orig_trigger;
 
 			if (handler) {
-				zend_jit_trace_exit_info *shared_exit_info = NULL;
-
 				t->exit_info = NULL;
 				if (t->exit_count) {
 					/* reallocate exit_info into shared memory */
-					shared_exit_info = (zend_jit_trace_exit_info*)zend_shared_alloc(
+					t->exit_info = (zend_jit_trace_exit_info*)zend_shared_alloc_copy(exit_info,
 						sizeof(zend_jit_trace_exit_info) * t->exit_count);
 
-					if (!shared_exit_info) {
+					if (!t->exit_info) {
 						if (t->stack_map) {
 							efree(t->stack_map);
 						}
 						ret = ZEND_JIT_TRACE_STOP_NO_SHM;
 						goto exit;
 					}
-					memcpy(shared_exit_info, exit_info,
-						sizeof(zend_jit_trace_exit_info) * t->exit_count);
-					t->exit_info = shared_exit_info;
 				}
 
 				if (t->stack_map_size) {
-					zend_jit_trace_stack *shared_stack_map = (zend_jit_trace_stack*)zend_shared_alloc(t->stack_map_size * sizeof(zend_jit_trace_stack));
+					zend_jit_trace_stack *shared_stack_map = (zend_jit_trace_stack*)zend_shared_alloc_copy(
+						t->stack_map,
+						t->stack_map_size * sizeof(zend_jit_trace_stack));
+					efree(t->stack_map);
+					t->stack_map = shared_stack_map;
 					if (!shared_stack_map) {
-						efree(t->stack_map);
 						ret = ZEND_JIT_TRACE_STOP_NO_SHM;
 						goto exit;
 					}
-					memcpy(shared_stack_map, t->stack_map, t->stack_map_size * sizeof(zend_jit_trace_stack));
-					efree(t->stack_map);
-					t->stack_map = shared_stack_map;
 			    }
 
 				zend_jit_link_side_trace(

ext/opcache/zend_shared_alloc.c

@@ -363,6 +363,14 @@ void *zend_shared_alloc(size_t size)
 	return NULL;
 }
 
+void *zend_shared_alloc_copy(const void *src, size_t size)
+{
+	void *dest = zend_shared_alloc(size);
+	if (dest != NULL)
+		memcpy(dest, src, size);
+	return dest;
+}
+
 static zend_always_inline zend_ulong zend_rotr3(zend_ulong key)
 {
 	return (key >> 3) | (key << ((sizeof(key) * 8) - 3));

ext/opcache/zend_shared_alloc.h

@@ -133,6 +133,14 @@ void zend_shared_alloc_shutdown(void);
 /* allocate shared memory block */
 void *zend_shared_alloc(size_t size);
 
+/**
+ * Allocate a shared memory block and copy raw data from the given
+ * source pointer into it.
+ *
+ * @return the new allocation or NULL if out of memory
+ */
+void *zend_shared_alloc_copy(const void *src, size_t size);
+
 /**
  * Wrapper for zend_shared_alloc() which aligns at 64-byte boundary if
  * AVX or SSE2 are used.