next_pcs = alpha_deal_with_atomic_sequence (gdbarch, pc);

  if (next_pcs != NULL)

    return next_pcs;

  next_pc = alpha_next_pc (regcache, pc);

/* True if whether a breakpoint/watchpoint triggered can be determined

   from the si_code of SIGTRAP's siginfo_t (TRAP_BRKPT/TRAP_HWBKPT).

   That is, if the kernel can tell us whether the thread executed a

   software breakpoint, we trust it.  The kernel will be determining

   that from the hardware (e.g., from which exception was raised in

   the CPU).  Relying on whether a breakpoint is planted in memory at

   the time the SIGTRAP is processed to determine whether the thread

   stopped for a software breakpoint can be too late.  E.g., the

   breakpoint could have been removed since.  Or the thread could have

   stepped an instruction the size of a breakpoint instruction, and

   before the stop is processed a breakpoint is inserted at its

   address.  Getting these wrong is disastrous on decr_pc_after_break

   architectures.  The moribund location mechanism helps with that

   somewhat but it is an heuristic, and can well fail.  Getting that

   information out of the kernel and ultimately out of the CPU is the

   way to go.  That said, some architecture may get the si_code wrong,

   and as such we're leaving fallback code in place.  We'll remove

   this after a while if no problem is reported.  */

#define USE_SIGTRAP_SIGINFO 1

/* The x86 kernel gets some of the si_code values backwards, like

   this:

   | what                                     | si_code    |

   |------------------------------------------+------------|

   | software breakpoints (int3)              | SI_KERNEL  |

   | single-steps                             | TRAP_TRACE |

   | single-stepping a syscall                | TRAP_BRKPT |

   | user sent SIGTRAP                        | 0          |

   | exec SIGTRAP (when no PTRACE_EVENT_EXEC) | 0          |

   | hardware breakpoints/watchpoints         | TRAP_HWBPT |

   That is, it reports SI_KERNEL for software breakpoints (and only

   for those), and TRAP_BRKPT for single-stepping a syscall...  If the

   kernel is ever fixed, we'll just have to detect it like we detect

   optional ptrace features: by forking and debugging ourselves,

   running to a breakpoint and checking what comes out of

   siginfo->si_code.

   The generic Linux target code should use GDB_ARCH_TRAP_BRKPT

   instead of TRAP_BRKPT to abstract out this x86 peculiarity.  */

#if defined __i386__ || defined __x86_64__

# define GDB_ARCH_TRAP_BRKPT SI_KERNEL

#else

# define GDB_ARCH_TRAP_BRKPT TRAP_BRKPT

#endif

#ifndef TRAP_HWBKPT

# define TRAP_HWBKPT 4

#endif