GDB是否有"逐步调用"指令？

Question

WinDBG和相关的Windows内核调试器支持"pc"命令,该命令运行目标直到到达下一个调用语句(在汇编中).换句话说,它在创建新的堆栈帧之前就中断了,与"完成"相反.GDB中的"开始"运行直到主要开始,但实质上我想要"开始",但带有"任何下一帧"的通配符.

我试图在GDB中找到类似的功能,但还没有找到它.

这可能吗？

示例WinDBG doc:http://windbg.info/doc/1-common-cmds.html#4_expr_and_cmds

Answer 1

简单回答:不,step-to-next-call不是GDB命令的一部分.

GDB/Python感知答案:不,它不是GDB命令的一部分,但它很容易实现!

我不确定你是否想在call指令执行之前或之后停止.

• 要在之前停止,您需要stepi/nexti(下一个汇编指令)直到您call在当前指令中看到:

  import gdb
  
  class StepBeforeNextCall (gdb.Command):
      def __init__ (self):
          super (StepBeforeNextCall, self).__init__ ("step-before-next-call",
                                                     gdb.COMMAND_OBSCURE)
  
      def invoke (self, arg, from_tty):
          arch = gdb.selected_frame().architecture()
  
          while True:
              current_pc = addr2num(gdb.selected_frame().read_register("pc"))
              disa = arch.disassemble(current_pc)[0]
              if "call" in disa["asm"]: # or startswith ?
                  break
  
              SILENT=True
              gdb.execute("stepi", to_string=SILENT)
  
          print("step-before-next-call: next instruction is a call.")
          print("{}: {}".format(hex(int(disa["addr"])), disa["asm"]))
  
  def addr2num(addr):
      try:
          return int(addr)  # Python 3
      except:
          return long(addr) # Python 2
  
  StepBeforeNextCall()
  

• 要在通话结束后停止,您需要计算当前的堆栈深度,然后step直到它更深:

  import gdb
  
  def callstack_depth():
      depth = 1
      frame = gdb.newest_frame()
      while frame is not None:
          frame = frame.older()
          depth += 1
      return depth
  
  class StepToNextCall (gdb.Command):
      def __init__ (self):
          super (StepToNextCall, self).__init__ ("step-to-next-call", 
                                                 gdb.COMMAND_OBSCURE)
  
      def invoke (self, arg, from_tty):
          start_depth = current_depth =callstack_depth()
  
          # step until we're one step deeper
          while current_depth == start_depth:
              SILENT=True
              gdb.execute("step", to_string=SILENT)
              current_depth = callstack_depth()
  
          # display information about the new frame
          gdb.execute("frame 0")
  
  StepToNextCall() 
  

只需将它放在一个文件中,source它与GDB(或在你的.gdbinit)中,它将为您提供新的命令step-before-next-call和step-to-next-call.

有相关文件:

• Python API内容表
• 基本的Python
• Python表示架构
• 从Python访问劣质堆栈帧.