Adjust branching

Instead of killing the last jump, avoid emitting it in the first place.

Author: iluuu1994

Zend/zend_compile.c

@@ -6641,6 +6641,10 @@ static void zend_compile_pipe(znode *result, zend_ast *ast)
 	zend_compile_expr(result, fcall_ast);
 }
 
+/* Exit in a joined branch for true/false, leaving the evaluated result in the
+ * given temporary. */
+#define ZEND_PM_LABEL_EMPTY ((uint32_t)-1)
+
 typedef struct {
 	bool inside_or_pattern;
 	zend_stack labels;
@@ -6725,51 +6729,16 @@ static void zend_pm_emit_jmpnz_ex(znode *result, uint32_t opnum_target)
 	SET_NODE(opline->result, result);
 }
 
-static void zend_pm_kill_last_op_if_jmp(zend_pm_context *context)
-{
-	zend_op_array *op_array = CG(active_op_array);
-	zend_op *opline = &op_array->opcodes[op_array->last - 1];
-	uint32_t *labels = zend_stack_base(&context->labels);
-	uint32_t label_lower_bound = -zend_stack_count(&context->labels);
-
-	uint32_t label_idx;
-	switch (opline->opcode) {
-		case ZEND_JMP:
-			label_idx = opline->op1.opline_num;
-			break;
-		case ZEND_JMPZ_EX:
-		case ZEND_JMPNZ_EX:
-			label_idx = opline->op2.opline_num;
-			break;
-		default:
-			return;
-	}
-
-	ZEND_ASSERT(label_idx >= label_lower_bound);
-	uint32_t label_target = labels[-label_idx];
-	ZEND_ASSERT(label_target == op_array->last);
-
-	MAKE_NOP(opline);
-	op_array->last--;
-
-	uint32_t *label = labels;
-	uint32_t *label_end = zend_stack_top(&context->labels);
-	while (label <= label_end) {
-		if (*label == label_target) {
-			(*label)--;
-		}
-		label++;
-	}
-}
-
 static void zend_pm_compile_expr_like(zend_ast *ast, znode *result, znode *expr_node, bool consume_expr, uint32_t false_opnum)
 {
 	znode value;
 	zend_compile_expr(&value, ast->child[0]);
 	zend_op *opline = zend_emit_op_tmp(NULL, expr_node->op_type == IS_CV || consume_expr ? ZEND_IS_IDENTICAL : ZEND_CASE_STRICT, expr_node, &value);
 	SET_NODE(opline->result, result);
 
-	zend_pm_emit_jmpz_ex(result, false_opnum);
+	if (false_opnum != ZEND_PM_LABEL_EMPTY) {
+		zend_pm_emit_jmpz_ex(result, false_opnum);
+	}
 }
 
 static void zend_pm_verify_parenthesized_compound_pattern(zend_ast *ast, zend_ast_kind kind)
@@ -6791,27 +6760,31 @@ static void zend_pm_compile_or(zend_ast *ast, znode *result, znode *expr_node, b
 	context->inside_or_pattern = true;
 
 	zend_ast_list *ast_list = zend_ast_get_list(ast);
-	uint32_t true_label = zend_pm_label_create(context);
-	uint32_t false_label = consume_expr ? zend_pm_label_create(context) : false_opnum;
+	uint32_t end_label = zend_pm_label_create(context);
+	bool create_false_label = consume_expr || false_opnum == ZEND_PM_LABEL_EMPTY;
+	uint32_t false_label = create_false_label ? end_label : false_opnum;
 	uint32_t next_label = 0;
 
 	for (uint32_t i = 0; i < ast_list->children - 1; i++) {
 		if (next_label) {
 			zend_pm_label_set_next(context, next_label);
 		}
 		next_label = zend_pm_label_create(context);
-		zend_compile_pattern(ast_list->child[i], result, expr_node, false, (uint32_t)-1, context);
-		zend_pm_emit_jmpnz_ex(result, true_label);
+		zend_compile_pattern(ast_list->child[i], result, expr_node, false, ZEND_PM_LABEL_EMPTY, context);
+		zend_pm_emit_jmpnz_ex(result, end_label);
 	}
 	zend_pm_label_set_next(context, next_label);
 
 	zend_compile_pattern(ast_list->child[ast_list->children - 1], result, expr_node, false, false_label, context);
 
-	zend_pm_label_set_next(context, true_label);
-	if (consume_expr) {
-		zend_pm_label_set_next(context, false_label);
-		zend_emit_op(NULL, ZEND_FREE, expr_node, NULL);
-		zend_pm_emit_jmpz_ex(result, false_opnum);
+	zend_pm_label_set_next(context, end_label);
+	if (create_false_label) {
+		if (consume_expr) {
+			zend_emit_op(NULL, ZEND_FREE, expr_node, NULL);
+		}
+		if (false_opnum != ZEND_PM_LABEL_EMPTY) {
+			zend_pm_emit_jmpz_ex(result, false_opnum);
+		}
 	}
 
 	context->inside_or_pattern = false;
@@ -6822,16 +6795,21 @@ static void zend_pm_compile_and(zend_ast *ast, znode *result, znode *expr_node,
 	zend_pm_verify_parenthesized_compound_pattern(ast, ZEND_AST_OR_PATTERN);
 
 	zend_ast_list *ast_list = zend_ast_get_list(ast);
-	uint32_t false_label = consume_expr ? zend_pm_label_create(context) : false_opnum;
+	bool create_false_label = consume_expr || false_opnum == ZEND_PM_LABEL_EMPTY;
+	uint32_t false_label = create_false_label ? zend_pm_label_create(context) : false_opnum;
 
 	for (uint32_t i = 0; i < ast_list->children; i++) {
 		zend_compile_pattern(ast_list->child[i], result, expr_node, false, false_label, context);
 	}
 
-	if (consume_expr) {
+	if (create_false_label) {
 		zend_pm_label_set_next(context, false_label);
-		zend_emit_op(NULL, ZEND_FREE, expr_node, NULL);
-		zend_pm_emit_jmpz_ex(result, false_opnum);
+		if (consume_expr) {
+			zend_emit_op(NULL, ZEND_FREE, expr_node, NULL);
+		}
+		if (false_opnum != ZEND_PM_LABEL_EMPTY) {
+			zend_pm_emit_jmpz_ex(result, false_opnum);
+		}
 	}
 }
 
@@ -6858,7 +6836,9 @@ static void zend_pm_compile_type(zend_ast *ast, znode *result, znode *expr_node,
 	if (consume_expr) {
 		zend_emit_op(NULL, ZEND_FREE, expr_node, NULL);
 	}
-	zend_pm_emit_jmpz_ex(result, false_opnum);
+	if (false_opnum != ZEND_PM_LABEL_EMPTY) {
+		zend_pm_emit_jmpz_ex(result, false_opnum);
+	}
 }
 
 static void zend_pm_copy_tmp(znode *dest, znode *src, bool consume)
@@ -6910,7 +6890,8 @@ static void zend_pm_compile_container(
 ) {
 	znode expr_copy_node;
 
-	uint32_t false_label = consume_expr ? zend_pm_label_create(context) : false_opnum;
+	bool create_false_label = consume_expr || false_opnum == ZEND_PM_LABEL_EMPTY;
+	uint32_t false_label = create_false_label ? zend_pm_label_create(context) : false_opnum;
 	zend_ast_list *element_list = zend_ast_get_list(ast->child[0]);
 
 	/* Make sure the value is actually of the right type. */
@@ -6966,10 +6947,14 @@ static void zend_pm_compile_container(
 		zend_compile_pattern(element_value_ast, result, &element_value_node, true, false_label, context);
 	}
 
-	if (consume_expr) {
+	if (create_false_label) {
 		zend_pm_label_set_next(context, false_label);
-		zend_emit_op(NULL, ZEND_FREE, expr_node, NULL);
-		zend_pm_emit_jmpz_ex(result, false_opnum);
+		if (consume_expr) {
+			zend_emit_op(NULL, ZEND_FREE, expr_node, NULL);
+		}
+		if (false_opnum != ZEND_PM_LABEL_EMPTY) {
+			zend_pm_emit_jmpz_ex(result, false_opnum);
+		}
 	}
 
 	if (has_implicit && has_explicit) {
@@ -6979,11 +6964,6 @@ static void zend_pm_compile_container(
 
 static void zend_compile_pattern(zend_ast *ast, znode *result, znode *expr_node, bool consume_expr, uint32_t false_opnum, zend_pm_context *context)
 {
-	bool create_label = false_opnum == (uint32_t)-1;
-	if (create_label) {
-		false_opnum = zend_pm_label_create(context);
-	}
-
 	switch (ast->kind) {
 		case ZEND_AST_EXPR_LIKE_PATTERN:
 			zend_pm_compile_expr_like(ast, result, expr_node, consume_expr, false_opnum);
@@ -7008,11 +6988,6 @@ static void zend_compile_pattern(zend_ast *ast, znode *result, znode *expr_node,
 			break;
 		EMPTY_SWITCH_DEFAULT_CASE();
 	}
-
-	if (create_label) {
-		zend_pm_label_set_next(context, false_opnum);
-		zend_pm_kill_last_op_if_jmp(context);
-	}
 }
 
 static void zend_pm_count_bindings(zend_ast **ast_ptr, void *context)
@@ -7061,7 +7036,7 @@ static void zend_emit_is(znode *result, znode *expr_node, bool consume_expr, zen
 	}
 
 	uint32_t start_opnum = get_next_op_number();
-	uint32_t false_label = context.num_bindings ? zend_pm_label_create(&context) : -1;
+	uint32_t false_label = context.num_bindings ? zend_pm_label_create(&context) : ZEND_PM_LABEL_EMPTY;
 	zend_compile_pattern(pattern_ast, result, &expr_copy_node, consume_expr, false_label, &context);
 
 	if (context.num_bindings) {