Merge branch 'coalesce_operator'

* coalesce_operator:
  Extended coalesce operator test case for ordering/short-circuiting
  Ensure not evaluated twice
  Added test
  Initial coalesce operator implementation

Zend/zend_ast.h

@@ -115,6 +115,7 @@ enum _zend_ast_kind {
 	ZEND_AST_NEW,
 	ZEND_AST_INSTANCEOF,
 	ZEND_AST_YIELD,
+	ZEND_AST_COALESCE,
 
 	ZEND_AST_STATIC,
 	ZEND_AST_WHILE,

Zend/zend_compile.c

@@ -5324,6 +5324,30 @@ void zend_compile_conditional(znode *result, zend_ast *ast TSRMLS_DC) /* {{{ */
 }
 /* }}} */
 
+void zend_compile_coalesce(znode *result, zend_ast *ast TSRMLS_DC) /* {{{ */
+{
+	zend_ast *expr_ast = ast->child[0];
+	zend_ast *default_ast = ast->child[1];
+
+	znode expr_node, default_node;
+	zend_op *opline;
+	uint32_t opnum;
+
+	zend_compile_var(&expr_node, expr_ast, BP_VAR_IS TSRMLS_CC);
+
+	opnum = get_next_op_number(CG(active_op_array));
+	zend_emit_op(result, ZEND_COALESCE, &expr_node, NULL TSRMLS_CC);
+
+	zend_compile_expr(&default_node, default_ast TSRMLS_CC);
+
+	opline = zend_emit_op(NULL, ZEND_QM_ASSIGN, &default_node, NULL TSRMLS_CC);
+	SET_NODE(opline->result, result);
+
+	opline = &CG(active_op_array)->opcodes[opnum];
+	opline->op2.opline_num = get_next_op_number(CG(active_op_array));
+}
+/* }}} */
+
 void zend_compile_print(znode *result, zend_ast *ast TSRMLS_DC) /* {{{ */
 {
 	zend_ast *expr_ast = ast->child[0];
@@ -6158,6 +6182,9 @@ void zend_compile_expr(znode *result, zend_ast *ast TSRMLS_DC) /* {{{ */
 		case ZEND_AST_CONDITIONAL:
 			zend_compile_conditional(result, ast TSRMLS_CC);
 			return;
+		case ZEND_AST_COALESCE:
+			zend_compile_coalesce(result, ast TSRMLS_CC);
+			return;
 		case ZEND_AST_PRINT:
 			zend_compile_print(result, ast TSRMLS_CC);
 			return;

Zend/zend_language_parser.y

@@ -67,6 +67,7 @@ static YYSIZE_T zend_yytnamerr(char*, const char*);
 %right T_YIELD
 %left '=' T_PLUS_EQUAL T_MINUS_EQUAL T_MUL_EQUAL T_DIV_EQUAL T_CONCAT_EQUAL T_MOD_EQUAL T_AND_EQUAL T_OR_EQUAL T_XOR_EQUAL T_SL_EQUAL T_SR_EQUAL T_POW_EQUAL
 %left '?' ':'
+%right T_COALESCE
 %left T_BOOLEAN_OR
 %left T_BOOLEAN_AND 
 %left '|'
@@ -221,6 +222,7 @@ static YYSIZE_T zend_yytnamerr(char*, const char*);
 %token T_NS_C            "__NAMESPACE__ (T_NS_C)"
 %token T_NS_SEPARATOR    "\\ (T_NS_SEPARATOR)"
 %token T_ELLIPSIS        "... (T_ELLIPSIS)"
+%token T_COALESCE        "?? (T_COALESCE)"
 %token T_POW             "** (T_POW)"
 %token T_POW_EQUAL       "**= (T_POW_EQUAL)"
 
@@ -827,6 +829,8 @@ expr_without_variable:
 			{ $$ = zend_ast_create(ZEND_AST_CONDITIONAL, $1, $3, $5); }
 	|	expr '?' ':' expr
 			{ $$ = zend_ast_create(ZEND_AST_CONDITIONAL, $1, NULL, $4); }
+	|	expr T_COALESCE expr
+			{ $$ = zend_ast_create(ZEND_AST_COALESCE, $1, $3); }
 	|	internal_functions_in_yacc { $$ = $1; }
 	|	T_INT_CAST expr		{ $$ = zend_ast_create_cast(IS_LONG, $2); }
 	|	T_DOUBLE_CAST expr	{ $$ = zend_ast_create_cast(IS_DOUBLE, $2); }

Zend/zend_language_scanner.l

@@ -1202,6 +1202,10 @@ NEWLINE ("\r"|"\n"|"\r\n")
 	return T_ELLIPSIS;
 }
 
+<ST_IN_SCRIPTING>"??" {
+	return T_COALESCE;
+}
+
 <ST_IN_SCRIPTING>"new" {
 	return T_NEW;
 }

Zend/zend_language_scanner_defs.h

@@ -1,4 +1,4 @@
-/* Generated by re2c 0.13.5 */
+/* Generated by re2c 0.13.6 */
 #line 3 "Zend/zend_language_scanner_defs.h"
 
 enum YYCONDTYPE {

Zend/zend_opcode.c

@@ -741,6 +741,7 @@ ZEND_API int pass_two(zend_op_array *op_array TSRMLS_DC)
 			case ZEND_JMPZ_EX:
 			case ZEND_JMPNZ_EX:
 			case ZEND_JMP_SET:
+			case ZEND_COALESCE:
 			case ZEND_NEW:
 			case ZEND_FE_RESET:
 			case ZEND_FE_FETCH:

Zend/zend_vm_def.h

@@ -5138,6 +5138,41 @@ ZEND_VM_HANDLER(152, ZEND_JMP_SET, CONST|TMP|VAR|CV, ANY)
 	ZEND_VM_NEXT_OPCODE();
 }
 
+ZEND_VM_HANDLER(169, ZEND_COALESCE, CONST|TMP|VAR|CV, ANY)
+{
+	USE_OPLINE
+	zend_free_op free_op1;
+	zval *value;
+	int is_ref = 0;
+
+	SAVE_OPLINE();
+	value = GET_OP1_ZVAL_PTR(BP_VAR_IS);
+
+	if ((OP1_TYPE == IS_VAR || OP1_TYPE == IS_CV) && Z_ISREF_P(value)) {
+		is_ref = 1;
+		value = Z_REFVAL_P(value);
+	}
+
+	if (Z_TYPE_P(value) > IS_NULL) {
+		ZVAL_COPY_VALUE(EX_VAR(opline->result.var), value);
+		if (OP1_TYPE == IS_CONST) {
+			if (UNEXPECTED(Z_OPT_COPYABLE_P(value))) {
+				zval_copy_ctor_func(EX_VAR(opline->result.var));
+			}
+		} else if (OP1_TYPE == IS_CV) {
+			if (Z_OPT_REFCOUNTED_P(value)) Z_ADDREF_P(value);
+		} else if (OP1_TYPE == IS_VAR && is_ref) {
+			if (Z_OPT_REFCOUNTED_P(value)) Z_ADDREF_P(value);
+			FREE_OP1();
+		}
+		ZEND_VM_JMP(opline->op2.jmp_addr);
+	}
+
+	FREE_OP1();
+	CHECK_EXCEPTION();
+	ZEND_VM_NEXT_OPCODE();
+}
+
 ZEND_VM_HANDLER(22, ZEND_QM_ASSIGN, CONST|TMP|VAR|CV, ANY)
 {
 	USE_OPLINE

Zend/zend_vm_execute.h

@@ -3291,6 +3291,40 @@ static int ZEND_FASTCALL  ZEND_JMP_SET_SPEC_CONST_HANDLER(ZEND_OPCODE_HANDLER_AR
 	ZEND_VM_NEXT_OPCODE();
 }
 
+static int ZEND_FASTCALL  ZEND_COALESCE_SPEC_CONST_HANDLER(ZEND_OPCODE_HANDLER_ARGS)
+{
+	USE_OPLINE
+
+	zval *value;
+	int is_ref = 0;
+
+	SAVE_OPLINE();
+	value = opline->op1.zv;
+
+	if ((IS_CONST == IS_VAR || IS_CONST == IS_CV) && Z_ISREF_P(value)) {
+		is_ref = 1;
+		value = Z_REFVAL_P(value);
+	}
+
+	if (Z_TYPE_P(value) > IS_NULL) {
+		ZVAL_COPY_VALUE(EX_VAR(opline->result.var), value);
+		if (IS_CONST == IS_CONST) {
+			if (UNEXPECTED(Z_OPT_COPYABLE_P(value))) {
+				zval_copy_ctor_func(EX_VAR(opline->result.var));
+			}
+		} else if (IS_CONST == IS_CV) {
+			if (Z_OPT_REFCOUNTED_P(value)) Z_ADDREF_P(value);
+		} else if (IS_CONST == IS_VAR && is_ref) {
+			if (Z_OPT_REFCOUNTED_P(value)) Z_ADDREF_P(value);
+
+		}
+		ZEND_VM_JMP(opline->op2.jmp_addr);
+	}
+
+	CHECK_EXCEPTION();
+	ZEND_VM_NEXT_OPCODE();
+}
+
 static int ZEND_FASTCALL  ZEND_QM_ASSIGN_SPEC_CONST_HANDLER(ZEND_OPCODE_HANDLER_ARGS)
 {
 	USE_OPLINE
@@ -10011,6 +10045,41 @@ static int ZEND_FASTCALL  ZEND_JMP_SET_SPEC_TMP_HANDLER(ZEND_OPCODE_HANDLER_ARGS
 	ZEND_VM_NEXT_OPCODE();
 }
 
+static int ZEND_FASTCALL  ZEND_COALESCE_SPEC_TMP_HANDLER(ZEND_OPCODE_HANDLER_ARGS)
+{
+	USE_OPLINE
+	zend_free_op free_op1;
+	zval *value;
+	int is_ref = 0;
+
+	SAVE_OPLINE();
+	value = _get_zval_ptr_tmp(opline->op1.var, execute_data, &free_op1 TSRMLS_CC);
+
+	if ((IS_TMP_VAR == IS_VAR || IS_TMP_VAR == IS_CV) && Z_ISREF_P(value)) {
+		is_ref = 1;
+		value = Z_REFVAL_P(value);
+	}
+
+	if (Z_TYPE_P(value) > IS_NULL) {
+		ZVAL_COPY_VALUE(EX_VAR(opline->result.var), value);
+		if (IS_TMP_VAR == IS_CONST) {
+			if (UNEXPECTED(Z_OPT_COPYABLE_P(value))) {
+				zval_copy_ctor_func(EX_VAR(opline->result.var));
+			}
+		} else if (IS_TMP_VAR == IS_CV) {
+			if (Z_OPT_REFCOUNTED_P(value)) Z_ADDREF_P(value);
+		} else if (IS_TMP_VAR == IS_VAR && is_ref) {
+			if (Z_OPT_REFCOUNTED_P(value)) Z_ADDREF_P(value);
+			zval_dtor(free_op1.var);
+		}
+		ZEND_VM_JMP(opline->op2.jmp_addr);
+	}
+
+	zval_dtor(free_op1.var);
+	CHECK_EXCEPTION();
+	ZEND_VM_NEXT_OPCODE();
+}
+
 static int ZEND_FASTCALL  ZEND_QM_ASSIGN_SPEC_TMP_HANDLER(ZEND_OPCODE_HANDLER_ARGS)
 {
 	USE_OPLINE
@@ -16791,6 +16860,41 @@ static int ZEND_FASTCALL  ZEND_JMP_SET_SPEC_VAR_HANDLER(ZEND_OPCODE_HANDLER_ARGS
 	ZEND_VM_NEXT_OPCODE();
 }
 
+static int ZEND_FASTCALL  ZEND_COALESCE_SPEC_VAR_HANDLER(ZEND_OPCODE_HANDLER_ARGS)
+{
+	USE_OPLINE
+	zend_free_op free_op1;
+	zval *value;
+	int is_ref = 0;
+
+	SAVE_OPLINE();
+	value = _get_zval_ptr_var(opline->op1.var, execute_data, &free_op1 TSRMLS_CC);
+
+	if ((IS_VAR == IS_VAR || IS_VAR == IS_CV) && Z_ISREF_P(value)) {
+		is_ref = 1;
+		value = Z_REFVAL_P(value);
+	}
+
+	if (Z_TYPE_P(value) > IS_NULL) {
+		ZVAL_COPY_VALUE(EX_VAR(opline->result.var), value);
+		if (IS_VAR == IS_CONST) {
+			if (UNEXPECTED(Z_OPT_COPYABLE_P(value))) {
+				zval_copy_ctor_func(EX_VAR(opline->result.var));
+			}
+		} else if (IS_VAR == IS_CV) {
+			if (Z_OPT_REFCOUNTED_P(value)) Z_ADDREF_P(value);
+		} else if (IS_VAR == IS_VAR && is_ref) {
+			if (Z_OPT_REFCOUNTED_P(value)) Z_ADDREF_P(value);
+			zval_ptr_dtor_nogc(free_op1.var);
+		}
+		ZEND_VM_JMP(opline->op2.jmp_addr);
+	}
+
+	zval_ptr_dtor_nogc(free_op1.var);
+	CHECK_EXCEPTION();
+	ZEND_VM_NEXT_OPCODE();
+}
+
 static int ZEND_FASTCALL  ZEND_QM_ASSIGN_SPEC_VAR_HANDLER(ZEND_OPCODE_HANDLER_ARGS)
 {
 	USE_OPLINE
@@ -33794,6 +33898,40 @@ static int ZEND_FASTCALL  ZEND_JMP_SET_SPEC_CV_HANDLER(ZEND_OPCODE_HANDLER_ARGS)
 	ZEND_VM_NEXT_OPCODE();
 }
 
+static int ZEND_FASTCALL  ZEND_COALESCE_SPEC_CV_HANDLER(ZEND_OPCODE_HANDLER_ARGS)
+{
+	USE_OPLINE
+
+	zval *value;
+	int is_ref = 0;
+
+	SAVE_OPLINE();
+	value = _get_zval_ptr_cv_BP_VAR_IS(execute_data, opline->op1.var TSRMLS_CC);
+
+	if ((IS_CV == IS_VAR || IS_CV == IS_CV) && Z_ISREF_P(value)) {
+		is_ref = 1;
+		value = Z_REFVAL_P(value);
+	}
+
+	if (Z_TYPE_P(value) > IS_NULL) {
+		ZVAL_COPY_VALUE(EX_VAR(opline->result.var), value);
+		if (IS_CV == IS_CONST) {
+			if (UNEXPECTED(Z_OPT_COPYABLE_P(value))) {
+				zval_copy_ctor_func(EX_VAR(opline->result.var));
+			}
+		} else if (IS_CV == IS_CV) {
+			if (Z_OPT_REFCOUNTED_P(value)) Z_ADDREF_P(value);
+		} else if (IS_CV == IS_VAR && is_ref) {
+			if (Z_OPT_REFCOUNTED_P(value)) Z_ADDREF_P(value);
+
+		}
+		ZEND_VM_JMP(opline->op2.jmp_addr);
+	}
+
+	CHECK_EXCEPTION();
+	ZEND_VM_NEXT_OPCODE();
+}
+
 static int ZEND_FASTCALL  ZEND_QM_ASSIGN_SPEC_CV_HANDLER(ZEND_OPCODE_HANDLER_ARGS)
 {
 	USE_OPLINE
@@ -47388,6 +47526,31 @@ void zend_init_opcodes_handlers(void)
   	ZEND_NULL_HANDLER,
   	ZEND_NULL_HANDLER,
   	ZEND_NULL_HANDLER,
+  	ZEND_COALESCE_SPEC_CONST_HANDLER,
+  	ZEND_COALESCE_SPEC_CONST_HANDLER,
+  	ZEND_COALESCE_SPEC_CONST_HANDLER,
+  	ZEND_COALESCE_SPEC_CONST_HANDLER,
+  	ZEND_COALESCE_SPEC_CONST_HANDLER,
+  	ZEND_COALESCE_SPEC_TMP_HANDLER,
+  	ZEND_COALESCE_SPEC_TMP_HANDLER,
+  	ZEND_COALESCE_SPEC_TMP_HANDLER,
+  	ZEND_COALESCE_SPEC_TMP_HANDLER,
+  	ZEND_COALESCE_SPEC_TMP_HANDLER,
+  	ZEND_COALESCE_SPEC_VAR_HANDLER,
+  	ZEND_COALESCE_SPEC_VAR_HANDLER,
+  	ZEND_COALESCE_SPEC_VAR_HANDLER,
+  	ZEND_COALESCE_SPEC_VAR_HANDLER,
+  	ZEND_COALESCE_SPEC_VAR_HANDLER,
+  	ZEND_NULL_HANDLER,
+  	ZEND_NULL_HANDLER,
+  	ZEND_NULL_HANDLER,
+  	ZEND_NULL_HANDLER,
+  	ZEND_NULL_HANDLER,
+  	ZEND_COALESCE_SPEC_CV_HANDLER,
+  	ZEND_COALESCE_SPEC_CV_HANDLER,
+  	ZEND_COALESCE_SPEC_CV_HANDLER,
+  	ZEND_COALESCE_SPEC_CV_HANDLER,
+  	ZEND_COALESCE_SPEC_CV_HANDLER,
   	ZEND_NULL_HANDLER
   };
   zend_opcode_handlers = (opcode_handler_t*)labels;

Zend/zend_vm_opcodes.c

@@ -21,7 +21,7 @@
 #include <stdio.h>
 #include <zend.h>
 
-const char *zend_vm_opcodes_map[169] = {
+const char *zend_vm_opcodes_map[170] = {
 	"ZEND_NOP",
 	"ZEND_ADD",
 	"ZEND_SUB",
@@ -191,6 +191,7 @@ const char *zend_vm_opcodes_map[169] = {
 	"ZEND_POW",
 	"ZEND_ASSIGN_POW",
 	"ZEND_BIND_GLOBAL",
+	"ZEND_COALESCE",
 };
 
 ZEND_API const char* zend_get_opcode_name(zend_uchar opcode) {

Zend/zend_vm_opcodes.h

@@ -179,5 +179,6 @@ ZEND_API const char *zend_get_opcode_name(zend_uchar opcode);
 #define ZEND_POW                             166
 #define ZEND_ASSIGN_POW                      167
 #define ZEND_BIND_GLOBAL                     168
+#define ZEND_COALESCE                        169
 
 #endif

tests/lang/operators/coalesce.phpt

@@ -0,0 +1,79 @@
+--TEST--
+Test ?? operator
+--FILE--
+<?php
+
+$var = 7;
+$var2 = NULL;
+
+$obj = new StdClass;
+$obj->boo = 7;
+
+$arr = [
+	2 => 7,
+	"foo" => "bar",
+	"foobar" => NULL,
+	"qux" => $obj,
+	"bing" => [
+		"bang"
+	]
+];
+
+function foobar() {
+	echo "called\n";
+	return ['a'];
+}
+
+var_dump($nonexistant_variable ?? 3);
+echo PHP_EOL;
+var_dump($var ?? 3);
+var_dump($var2 ?? 3);
+echo PHP_EOL;
+var_dump($obj->boo ?? 3);
+var_dump($obj->bing ?? 3);
+var_dump($arr["qux"]->boo ?? 3);
+var_dump($arr["qux"]->bing ?? 3);
+echo PHP_EOL;
+var_dump($arr[2] ?? 3);
+var_dump($arr["foo"] ?? 3);
+var_dump($arr["foobar"] ?? 3);
+var_dump($arr["qux"] ?? 3);
+var_dump($arr["bing"][0] ?? 3);
+var_dump($arr["bing"][1] ?? 3);
+echo PHP_EOL;
+var_dump(foobar()[0] ?? false);
+echo PHP_EOL;
+function f($x)
+{
+    printf("%s(%d)\n", __FUNCTION__, $x);
+    return $x;
+}
+
+$a = f(null) ?? f(1) ?? f(2);
+?>
+--EXPECTF--
+int(3)
+
+int(7)
+int(3)
+
+int(7)
+int(3)
+int(7)
+int(3)
+
+int(7)
+string(3) "bar"
+int(3)
+object(stdClass)#%d (%d) {
+  ["boo"]=>
+  int(7)
+}
+string(4) "bang"
+int(3)
+
+called
+string(1) "a"
+
+f(0)
+f(1)