implement some CR feedback

Author: morrisonlevi

UPGRADING.INTERNALS

@@ -336,14 +336,8 @@ PHP 8.4 INTERNALS UPGRADE NOTES
 * DO_ICALL, DO_FCALL, and DO_FCALL_BY_NAME now call zend_interrupt_function
   while the internal frame is still on the stack. This means interrupt handlers
   will now see the internal call. If your interrupt handler does something like
-  switching EG(current_execute_data), it probably needs to do something more
-  similar to a fiber switch, or at least not do so when internal frames are on
-  top anymore.
-
-* RETURN, RETURN_BY_REF, GENERATOR_RETURN, and CALL_TRAMPOLINE now do a check
-  for a VM interrupt and call zend_timeout/zend_interrupt_function after the
-  ZEND_OBSERVER_FCALL_END call.
-
+  switching EG(current_execute_data), it should not do so if an internal func
+  is on top.
 * New FRAMELESS_ICALL_[0,3] opcodes for faster internal function calls have been
   added. These opcodes don't create a stack frame, but pass arguments via opcode
   operands. They only work for functions that are known at compile-time, and

Zend/zend.h

@@ -342,14 +342,15 @@ extern ZEND_API zend_write_func_t zend_write;
 extern ZEND_API FILE *(*zend_fopen)(zend_string *filename, zend_string **opened_path);
 extern ZEND_API void (*zend_ticks_function)(int ticks);
 
-/* Called by the VM in certain places like at the end of function calls or
- * jumps, if EG(vm_interrupt) has been set.
+/* Called by the VM in certain places like at the loop header, user function
+ * entry, and after internal function calls, if EG(vm_interrupt) has been set.
  *
  * If this is used to switch the EG(current_execute_data), such as implementing
  * a coroutine scheduler, then it needs to check the top frame to see if it's
- * an internal function. If so, it needs to do something similar to a fiber
- * switch, or at the very least delay switching until the internal frame is no
- * longer on top. Prior to PHP 8.0, this check was not necessary. In PHP 8.0
+ * an internal function. If an internal function is on top, then the frame
+ * shouldn't be switched away.
+ *
+ * Prior to PHP 8.0, this check was not necessary. In PHP 8.0,
  * zend_call_function started calling zend_interrupt_function, and in 8.4 the
  * DO_*CALL* opcodes started calling the zend_interrupt_function while the
  * internal frame is still on top.

Zend/zend_execute.c

@@ -5520,7 +5520,8 @@ static zend_always_inline zend_execute_data *_zend_vm_stack_push_call_frame(uint
 
 #define ZEND_VM_SET_OPCODE(new_op) \
 	CHECK_SYMBOL_TABLES() \
-	OPLINE = new_op;
+	OPLINE = new_op; \
+	ZEND_VM_INTERRUPT_CHECK()
 
 #define ZEND_VM_SET_RELATIVE_OPCODE(opline, offset) \
 	ZEND_VM_SET_OPCODE(ZEND_OFFSET_TO_OPLINE(opline, offset))

Zend/zend_vm_def.h

@@ -4099,6 +4099,8 @@ ZEND_VM_HOT_HANDLER(129, ZEND_DO_ICALL, ANY, ANY, SPEC(RETVAL,OBSERVER))
 	}
 
 	ZEND_VM_SET_OPCODE(opline + 1);
+	CHECK_SYMBOL_TABLES()
+	OPLINE = opline + 1;
 	ZEND_VM_CONTINUE();
 }
 
@@ -4227,7 +4229,8 @@ ZEND_VM_C_LABEL(fcall_by_name_end):
 		zend_rethrow_exception(execute_data);
 		HANDLE_EXCEPTION();
 	}
-	ZEND_VM_SET_OPCODE(opline + 1);
+	CHECK_SYMBOL_TABLES()
+	OPLINE = opline + 1;
 	ZEND_VM_CONTINUE();
 }
 
@@ -4347,7 +4350,8 @@ ZEND_VM_C_LABEL(fcall_end):
 		HANDLE_EXCEPTION();
 	}
 
-	ZEND_VM_SET_OPCODE(opline + 1);
+	CHECK_SYMBOL_TABLES()
+	OPLINE = opline + 1;
 	ZEND_VM_CONTINUE();
 }