Cleanup and fixes

Author: nielsdos

Zend/Optimizer/dfa_pass.c

@@ -1067,11 +1067,10 @@ static bool zend_dfa_try_to_replace_result(zend_op_array *op_array, zend_ssa *ss
 }
 
 /* Sets a flag on SEND ops when a copy can be a avoided. */
-static void zend_dfa_optimize_send_copies(zend_op_array *op_array, zend_ssa *ssa)
+static void zend_dfa_optimize_send_copies(zend_op_array *op_array, zend_ssa *ssa, zend_call_info **call_map)
 {
 	for (int v = 0; v < ssa->vars_count; v++) {
-		int var = ssa->vars[v].var;
-		if (var >= op_array->last_var) {
+		if (ssa->vars[v].var >= op_array->last_var) {
 			continue;
 		}
 
@@ -1080,33 +1079,21 @@ static void zend_dfa_optimize_send_copies(zend_op_array *op_array, zend_ssa *ssa
 			continue;
 		}
 
-#if 0
-		fprintf(stderr, "cv %d: ", v);
-		zend_dump_var(op_array, IS_CV, v);
-		fprintf(stderr, "\n");
-		fprintf(stderr, "type %x\n", type);
-#endif
-
 		int use = ssa->vars[v].use_chain;
 		if (use >= 0
 			&& op_array->opcodes[use].opcode == ZEND_SEND_VAR
 			&& op_array->opcodes[use].op2_type == IS_UNUSED) {
 			int next_use = zend_ssa_next_use(ssa->ops, v, use);
-#if 0
-			if (next_use >= 0 && op_array->opcodes[next_use].opcode == ZEND_ASSIGN) {
-				fprintf(stderr, "v=%d next_use %d (%d, %d, %d, %d)\n", v, next_use, ssa->ops[next_use].result_def, ssa->ops[next_use].result_use, ssa->ops[next_use].op1_use, ssa->ops[next_use].op2_use);
-				fprintf(stderr, "next_use var: %d (var=%d)\n", ssa->vars[next_use].var, var);
-				fprintf(stderr, "OP1: %d (var=%d)\n", ssa->vars[ssa->ops[next_use].op1_def].var, var);
-			}
-#endif
-			/* The next use must be an assignment, and there should be no uses after that.
+
+			/* The next use must be an assignment of the call result, and there should be no other uses.
 			 * If there is no next use or the next use is not an assignment, then we cannot safely 
-			 * perform the operation without a copy because the nullified value would be observable indirectly
+			 * perform the operation without a copy because the undef value would be observable indirectly
 			 * through compact(), func_get_args(), ... */
 			if (next_use >= 0
 				&& op_array->opcodes[next_use].opcode == ZEND_ASSIGN
 				&& ssa->ops[next_use].op1_use == v
-				&& ssa->vars[v].var == var
+				&& ssa->ops[next_use].op2_use >= 0
+				&& ssa->ops[call_map[use]->caller_call_opline - op_array->opcodes].result_def == ssa->ops[next_use].op2_use
 				&& zend_ssa_next_use(ssa->ops, v, next_use) < 0) {
 				ZEND_ASSERT(op_array->opcodes[use].extended_value == 0);
 				op_array->opcodes[use].extended_value = 1;
@@ -1175,7 +1162,7 @@ void zend_dfa_optimize_op_array(zend_op_array *op_array, zend_optimizer_ctx *ctx
 
 		/* Optimization should not be done on main because of globals */
 		if (op_array->function_name) {
-			zend_dfa_optimize_send_copies(op_array, ssa);
+			zend_dfa_optimize_send_copies(op_array, ssa, call_map);
 		}
 
 		for (v = op_array->last_var; v < ssa->vars_count; v++) {

Zend/zend_vm_def.h

@@ -9926,8 +9926,7 @@ ZEND_VM_HOT_TYPE_SPEC_HANDLER(ZEND_SEND_VAR, op->op2_type == IS_UNUSED && op->ex
 	arg = ZEND_CALL_VAR(EX(call), opline->result.var);
 
 	ZVAL_COPY_VALUE(arg, varptr);
-	ZVAL_NULL(varptr);//TODO: what if this is uninit?
-	//fprintf(stderr, "Hello world, %d\n", Z_REFCOUNTED_P(arg));
+	ZVAL_UNDEF(varptr);
 
 	ZEND_VM_NEXT_OPCODE();
 }