Zend VMにおける例外の実装
0 likes720 views
The document discusses exception handling on the Zend VM. It provides code examples of throwing, catching, and rethrowing exceptions. It also shows how exceptions are handled when using try/catch blocks and try/finally blocks, including how the finally block is always executed even if an exception is thrown in the try block.
Zend VMにおける例外の実装
- 1. Explaining exception handling on Zend VM
- 2. ❖ ❖ ❖ ❖ ❖
- 4. ❖ ❖ ❖ ❖
- 5. ❖ ❖ ❖ ❖
- 6. ❖
- 7. ❖
- 8. ❖ ❖ ❖ ❖ ❖ ❖
- 9. ❖ ❖
- 10. ❖ ❖
- 11. ❖ <?php function mydiv($a, $b) { return $b ? $a / $b : 0; } $ php -dopcache.enable_cli=1 -dopcache.opt_debug_level=0x10000 mydiv.php
- 12. L0 (2): CV0($a) = RECV 1 L1 (2): CV1($b) = RECV 2 L2 (3): JMPZ CV1($b) L6 L3 (3): T2 = DIV CV0($a) CV1($b) L4 (3): T3 = QM_ASSIGN T2 L5 (3): JMP L7 L6 (3): T3 = QM_ASSIGN int(0) L7 (3): RETURN T3 L8 (4): RETURN null ❖ ❖ ❖
- 13. ❖ JMPZ CV1($b) L6 T2 = DIV CV0($a) CV1($b) ❖
- 15. ❖ ❖ ❖ ❖ ❖
- 16. ❖ ❖ ❖ ❖ ❖ ❖
- 17. ❖ ❖ ❖ ❖
- 18. <?php function bar() { $e = new Exception(); throw $e; try { throw $e; } catch (FooException $e) { throw $e; } catch (BarException $e) { return 0; } } ❖
- 19. L0 (4): V1 = NEW 0 string("Exception") L1 (4): DO_FCALL L2 (3): ASSIGN CV0($e) V1 L3 (4): THROW CV0($e) L4 (6): THROW CV0($e) L5 (6): JMP L11 L6 (7): CV0($e) = CATCH string("FooException") L9 L7 (8): THROW CV0($e) L8 (8): JMP L11 L9 (9): CV0($e) = CATCH string("BarException") L10 (10): RETURN int(0) L11 (12): RETURN null EXCEPTION TABLE: L4, L6, -, - ❖
- 21. ❖ THROW CV0($e) ❖ CV0($e) = CATCH string("FooException") L9
- 25. ZEND_API ZEND_COLD void zend_throw_exception_internal (zval *exception) /* {{{ */ { if (exception != NULL) { EG(exception) = Z_OBJ_P(exception); ❖ ❖ ❖
- 27. ❖ ❖ ❖ ❖ ❖ ❖ ❖
- 28. ❖ ❖
- 29. L0 (4): V1 = NEW 0 string("Exception") L1 (4): DO_FCALL L2 (3): ASSIGN CV0($e) V1 L3 (4): THROW CV0($e) L4 (6): THROW CV0($e) L5 (6): JMP L11 L6 (7): CV0($e) = CATCH string("FooException") L9 L7 (8): THROW CV0($e) L8 (8): JMP L11 L9 (9): CV0($e) = CATCH string("BarException") L10 (10): RETURN int(0) L11 (12): RETURN null EXCEPTION TABLE: L4, L6, -, - ❖
- 30. ❖ ❖ ❖ ❖
- 31. if (ce != catch_ce) { if (!catch_ce || !instanceof_function(ce, catch_ce)) { if (opline->extended_value & ZEND_LAST_CATCH) { zend_rethrow_exception(execute_data); HANDLE_EXCEPTION(); } ZEND_VM_JMP_EX(OP_JMP_ADDR(opline, opline->op2), 0); } } ❖ ❖ ❖ ❖
- 32. static zend_always_inline void zend_rethrow_exception(zend_execute_data *execute_data) { if (EX(opline)->opcode != ZEND_HANDLE_EXCEPTION) { EG(opline_before_exception) = EX(opline); EX(opline) = EG(exception_op); } } ❖ ❖ ❖ ❖
- 34. CV0($e) = CATCH string("FooException") L9 ❖ ❖ ❖
- 35. ❖ ❖ ❖ ❖ ❖
- 36. ❖ ❖ ❖ ❖ ❖ ❖
- 37. ❖ ❖ ❖ ❖
- 38. <?php function baz() { try { throw new Exception(); } finally { return 0; } } ❖
- 39. <?php function baz() { try { throw new Exception(); } finally { return 0; } } ❖ ❖ ❖
- 40. L0 (4): V1 = NEW 0 string("Exception") L1 (4): DO_FCALL L2 (4): THROW V1 L3 (5): T0 = FAST_CALL L5 L4 (5): JMP L8 L5 (6): DISCARD_EXCEPTION T0 L6 (6): RETURN int(0) L7 (6): FAST_RET T0 L8 (8): RETURN null EXCEPTION TABLE: L0, -, L5, L7 ❖ ❖
- 41. ❖ ❖ ❖ ❖
- 42. <?php function baz() { try { throw new Exception(1); } finally { throw new Exception(2); } } ❖
- 43. <?php function baz() { try { throw new Exception(1); } finally { throw new Exception(2); } } ❖ ❖
- 44. try { baz(); } catch (Exception $e) { echo $e->getMessage(); // 2 echo $e->getPrevious()->getMessage(); // 1 } ❖ ❖
- 45. ❖ ❖ ❖ ❖ ❖
- 46. ❖ ❖ ❖ ❖
- 47. ❖ ❖
- 48. ❖ ❖ ❖ ❖