gdb/displaced-stepping.h

   1 #ifndef DISPLACED_STEPPING_H
   2 #define DISPLACED_STEPPING_H
   3
   4 #include "gdbsupport/byte-vector.h"
   5
   6 struct gdbarch;
   7 struct thread_info;
   8
   9 enum displaced_step_prepare_status
  10 {
  11   /* A displaced stepping buffer was successfully allocated and prepared.  */
  12   DISPLACED_STEP_PREPARE_STATUS_OK,
  13
  14   /* Something bad happened.  */
  15   DISPLACED_STEP_PREPARE_STATUS_ERROR,
  16
  17   /* Not enough resources are available at this time, try again later.  */
  18   DISPLACED_STEP_PREPARE_STATUS_UNAVAILABLE,
  19 };
  20
  21 enum displaced_step_finish_status
  22 {
  23   /* The instruction was stepped and fixed up.  */
  24   DISPLACED_STEP_FINISH_STATUS_OK,
  25
  26   /* The instruction was not stepped.  */
  27   DISPLACED_STEP_FINISH_STATUS_NOT_EXECUTED,
  28 };
  29
  30 /* Data returned by a gdbarch displaced_step_copy_insn method, to be passed to
  31    the matching displaced_step_fixup method.  */
  32
  33 struct displaced_step_copy_insn_closure
  34 {
  35   virtual ~displaced_step_copy_insn_closure () = 0;
  36 };
  37
  38 typedef std::unique_ptr<displaced_step_copy_insn_closure>
  39   displaced_step_copy_insn_closure_up;
  40
  41 /* A simple displaced step closure that contains only a byte buffer.  */
  42
  43 struct buf_displaced_step_copy_insn_closure : displaced_step_copy_insn_closure
  44 {
  45   buf_displaced_step_copy_insn_closure (int buf_size)
  46   : buf (buf_size)
  47   {}
  48
  49   gdb::byte_vector buf;
  50 };
  51
  52 /* Per-inferior displaced stepping state.  */
  53
  54 struct displaced_step_inferior_state
  55 {
  56   displaced_step_inferior_state ()
  57   {
  58     reset ();
  59   }
  60
  61   /* Put this object back in its original state.  */
  62   void reset ()
  63   {
  64     failed_before = false;
  65   }
  66
  67   /* True if preparing a displaced step ever failed.  If so, we won't
  68      try displaced stepping for this inferior again.  */
  69   bool failed_before;
  70 };
  71
  72 /* Per-thread displaced stepping state.  */
  73
  74 struct displaced_step_thread_state
  75 {
  76   /* Return true if this thread is currently executing a displaced step.  */
  77   bool in_progress () const
  78   { return m_original_gdbarch != nullptr; }
  79
  80   /* Return the gdbarch of the thread prior to the step.  */
  81   gdbarch *get_original_gdbarch () const
  82   { return m_original_gdbarch; }
  83
  84   /* Mark this thread as currently executing a displaced step.
  85
  86      ORIGINAL_GDBARCH is the current gdbarch of the thread (before the step
  87      is executed).  */
  88   void set (gdbarch *original_gdbarch)
  89   { m_original_gdbarch = original_gdbarch; }
  90
  91   /* mark this thread as no longer executing a displaced step.  */
  92   void reset ()
  93   { m_original_gdbarch = nullptr; }
  94
  95 private:
  96   gdbarch *m_original_gdbarch = nullptr;
  97 };
  98
  99 /* Manage access to a single displaced stepping buffer, without any
 100    sharing.  */
 101
 102 struct single_displaced_buffer_manager
 103 {
 104   single_displaced_buffer_manager (CORE_ADDR buffer_addr)
 105     : m_buffer_addr (buffer_addr)
 106   {}
 107
 108   displaced_step_prepare_status prepare (thread_info *thread);
 109
 110   displaced_step_finish_status finish (gdbarch *arch, thread_info *thread,
 111                                        gdb_signal sig);
 112
 113 private:
 114
 115   CORE_ADDR m_original_pc;
 116   CORE_ADDR m_buffer_addr;
 117
 118   /* If set, the thread currently using the buffer.  */
 119   thread_info *m_current_thread = nullptr;
 120
 121   gdb::byte_vector m_saved_copy;
 122   displaced_step_copy_insn_closure_up m_copy_insn_closure;
 123 };
 124
 125
 126 #endif /* DISPLACED_STEPPING_H */