Fix handling of abstract/deprecated exception

The exception mechanism assumes that exceptions from DO_FCALL are
already happening after the function call. This means that we are
currently leaking the passed arguments, and I think we can also
corrupt the VM stack due to incorrect frame linking in some cases
(there are assertion failures if the VM stack page size is reduced).

Instead handle the stack frame freeing manually for this special
case.

Author: nikic

Zend/tests/call_to_abstract_method_args.phpt

@@ -0,0 +1,18 @@
+--TEST--
+Check that arguments are freed when a call to an abstract method throws
+--FILE--
+<?php
+
+abstract class Test {
+    abstract static function method();
+}
+
+try {
+    Test::method(new stdClass);
+} catch (Error $e) {
+    echo $e->getMessage(), "\n";
+}
+
+?>
+--EXPECT--
+Cannot call abstract method Test::method()

Zend/zend_execute.c

@@ -1537,6 +1537,12 @@ static zend_never_inline ZEND_COLD void ZEND_FASTCALL zend_deprecated_function(c
 		ZSTR_VAL(fbc->common.function_name));
 }
 
+static zend_never_inline ZEND_COLD void ZEND_FASTCALL zend_abstract_method(const zend_function *fbc)
+{
+	zend_throw_error(NULL, "Cannot call abstract method %s::%s()",
+		ZSTR_VAL(fbc->common.scope->name), ZSTR_VAL(fbc->common.function_name));
+}
+
 static zend_never_inline void zend_assign_to_string_offset(zval *str, zval *dim, zval *value OPLINE_DC EXECUTE_DATA_DC)
 {
 	zend_uchar c;

Zend/zend_vm_def.h

@@ -1047,16 +1047,6 @@ ZEND_VM_COLD_HELPER(zend_this_not_in_object_context_helper, ANY, ANY)
 	HANDLE_EXCEPTION();
 }
 
-ZEND_VM_COLD_HELPER(zend_abstract_method_helper, ANY, ANY, zend_function *func)
-{
-	USE_OPLINE
-
-	SAVE_OPLINE();
-	zend_throw_error(NULL, "Cannot call abstract method %s::%s()", ZSTR_VAL(func->common.scope->name), ZSTR_VAL(func->common.function_name));
-	UNDEF_RESULT();
-	HANDLE_EXCEPTION();
-}
-
 ZEND_VM_COLD_HELPER(zend_undefined_function_helper, ANY, ANY)
 {
 	USE_OPLINE
@@ -4143,12 +4133,15 @@ ZEND_VM_HOT_HANDLER(60, ZEND_DO_FCALL, ANY, ANY, SPEC(RETVAL))
 	EX(call) = call->prev_execute_data;
 	if (UNEXPECTED((fbc->common.fn_flags & (ZEND_ACC_ABSTRACT|ZEND_ACC_DEPRECATED)) != 0)) {
 		if (UNEXPECTED((fbc->common.fn_flags & ZEND_ACC_ABSTRACT) != 0)) {
-			ZEND_VM_DISPATCH_TO_HELPER(zend_abstract_method_helper, func, fbc);
+			zend_abstract_method(fbc);
+ZEND_VM_C_LABEL(fcall_except):
+			UNDEF_RESULT();
+			zend_vm_stack_free_args(call);
+			ZEND_VM_C_GOTO(fcall_end);
 		} else {
 			zend_deprecated_function(fbc);
 			if (UNEXPECTED(EG(exception) != NULL)) {
-				UNDEF_RESULT();
-				HANDLE_EXCEPTION();
+				ZEND_VM_C_GOTO(fcall_except);
 			}
 		}
 	}

Zend/zend_vm_execute.h

@@ -781,16 +781,6 @@ static zend_never_inline ZEND_COLD ZEND_OPCODE_HANDLER_RET ZEND_FASTCALL zend_th
 	HANDLE_EXCEPTION();
 }
 
-static zend_never_inline ZEND_COLD ZEND_OPCODE_HANDLER_RET ZEND_FASTCALL zend_abstract_method_helper_SPEC(zend_function *func ZEND_OPCODE_HANDLER_ARGS_DC)
-{
-	USE_OPLINE
-
-	SAVE_OPLINE();
-	zend_throw_error(NULL, "Cannot call abstract method %s::%s()", ZSTR_VAL(func->common.scope->name), ZSTR_VAL(func->common.function_name));
-	UNDEF_RESULT();
-	HANDLE_EXCEPTION();
-}
-
 static zend_never_inline ZEND_COLD ZEND_OPCODE_HANDLER_RET ZEND_FASTCALL zend_undefined_function_helper_SPEC(ZEND_OPCODE_HANDLER_ARGS)
 {
 	USE_OPLINE
@@ -1557,12 +1547,15 @@ static ZEND_VM_HOT ZEND_OPCODE_HANDLER_RET ZEND_FASTCALL ZEND_DO_FCALL_SPEC_RETV
 	EX(call) = call->prev_execute_data;
 	if (UNEXPECTED((fbc->common.fn_flags & (ZEND_ACC_ABSTRACT|ZEND_ACC_DEPRECATED)) != 0)) {
 		if (UNEXPECTED((fbc->common.fn_flags & ZEND_ACC_ABSTRACT) != 0)) {
-			ZEND_VM_TAIL_CALL(zend_abstract_method_helper_SPEC(fbc ZEND_OPCODE_HANDLER_ARGS_PASSTHRU_CC));
+			zend_abstract_method(fbc);
+fcall_except:
+			UNDEF_RESULT();
+			zend_vm_stack_free_args(call);
+			goto fcall_end;
 		} else {
 			zend_deprecated_function(fbc);
 			if (UNEXPECTED(EG(exception) != NULL)) {
-				UNDEF_RESULT();
-				HANDLE_EXCEPTION();
+				goto fcall_except;
 			}
 		}
 	}
@@ -1668,12 +1661,15 @@ static ZEND_VM_HOT ZEND_OPCODE_HANDLER_RET ZEND_FASTCALL ZEND_DO_FCALL_SPEC_RETV
 	EX(call) = call->prev_execute_data;
 	if (UNEXPECTED((fbc->common.fn_flags & (ZEND_ACC_ABSTRACT|ZEND_ACC_DEPRECATED)) != 0)) {
 		if (UNEXPECTED((fbc->common.fn_flags & ZEND_ACC_ABSTRACT) != 0)) {
-			ZEND_VM_TAIL_CALL(zend_abstract_method_helper_SPEC(fbc ZEND_OPCODE_HANDLER_ARGS_PASSTHRU_CC));
+			zend_abstract_method(fbc);
+fcall_except:
+			UNDEF_RESULT();
+			zend_vm_stack_free_args(call);
+			goto fcall_end;
 		} else {
 			zend_deprecated_function(fbc);
 			if (UNEXPECTED(EG(exception) != NULL)) {
-				UNDEF_RESULT();
-				HANDLE_EXCEPTION();
+				goto fcall_except;
 			}
 		}
 	}