hphp/runtime/vm/async-flow-stepper.h

   1 /*
   2    +----------------------------------------------------------------------+
   3    | HipHop for PHP                                                       |
   4    +----------------------------------------------------------------------+
   5    | Copyright (c) 2010-present Facebook, Inc. (http://www.facebook.com)  |
   6    +----------------------------------------------------------------------+
   7    | This source file is subject to version 3.01 of the PHP license,      |
   8    | that is bundled with this package in the file LICENSE, and is        |
   9    | available through the world-wide-web at the following url:           |
  10    | http://www.php.net/license/3_01.txt                                  |
  11    | If you did not receive a copy of the PHP license and are unable to   |
  12    | obtain it through the world-wide-web, please send a note to          |
  13    | license@php.net so we can mail you a copy immediately.               |
  14    +----------------------------------------------------------------------+
  15 */
  16
  17 #pragma once
  18
  19 #include "hphp/runtime/vm/act-rec.h"
  20 #include "hphp/runtime/vm/pc-filter.h"
  21
  22 namespace HPHP {
  23
  24 enum class AsyncStepperStage {
  25   Disabled,       // Not enabled.
  26   StepOver,       // Normal step over did not counter "await" opcode yet.
  27   StepOverAwait,  // In the middle of step over "await" opcode.
  28   WaitResume,     // Wait for resume internal breakpoint to hit.
  29 };
  30
  31 // Indicate if AsyncFlowStepper has handled this opcode or not.
  32 enum class AsyncStepHandleOpcodeResult {
  33   Unhandled,  // Not handled, other logic should handle it.
  34   Handled,    // Handled, other stepping logic should not handle it.
  35   Completed,  // Async stepping completes.
  36 };
  37
  38 /**
  39  * This stepper is responsible for doing logic async
  40  * stepping over "await" opcode.
  41  * Caller should call setup() before stepping
  42  * and pass each step opcode to handleOpcode().
  43  */
  44 struct AsyncFlowStepper {
  45 public:
  46   void setup();
  47   AsyncStepHandleOpcodeResult handleOpcode(PC pc);
  48   void handleExceptionThrown();
  49   bool handleExceptionHandler();
  50
  51 private:
  52   void handleBlockedAwaitOpcode(PC pc);
  53   bool isActRecOnAsyncStack(const ActRec* target);
  54   void stepOverAwaitOpcode();
  55   void captureResumeIdAfterAwait();
  56   void setResumeInternalBreakpoint(PC pc);
  57   bool didResumeBreakpointTrigger(PC pc);
  58   const ActRec* getAsyncResumableId(const ActRec* fp);
  59   void updateStepStartStackDepth();
  60   bool isCompleted(PC pc);
  61   void reset();
  62
  63 private:
  64   AsyncStepperStage m_stage{AsyncStepperStage::Disabled};
  65   // ActRec address that issued current async operation
  66   // We used it to check if the completed async operation
  67   // is the one we are current stepping.
  68   ActRec* m_asyncResumableId{nullptr};
  69   int m_stepStartStackDepth{0};
  70   // Whether there is an exception thrown for current
  71   // stepped async operation.
  72   bool m_isCurrentAsyncStepException{false};
  73
  74   PCFilter m_stepRangeFlowFilter;
  75   PCFilter m_awaitOpcodeBreakpointFilter;
  76   PCFilter m_resumeBreakpointFilter;
  77 };
  78
  79 }
  80