tracepoints: Work with the tracequery's .o rather than .ko

[systemtap.git] / task_finder.cxx

// task finder for user tapsets
// Copyright (C) 2005-2009 Red Hat Inc.
// Copyright (C) 2005-2007 Intel Corporation.
// Copyright (C) 2008 James.Bottomley@HansenPartnership.com
//
// This file is part of systemtap, and is free software.  You can
// redistribute it and/or modify it under the terms of the GNU General
// Public License (GPL); either version 2, or (at your option) any
// later version.


#include "session.h"
#include "tapsets.h"
#include "task_finder.h"
#include "translate.h"
#include "util.h"

#include <cstring>
#include <string>


using namespace std;
using namespace __gnu_cxx;


// ------------------------------------------------------------------------
// task_finder derived 'probes': These don't really exist.  The whole
// purpose of the task_finder_derived_probe_group is to make sure that
// stap_start_task_finder()/stap_stop_task_finder() get called only
// once and in the right place.
// ------------------------------------------------------------------------

struct task_finder_derived_probe: public derived_probe
{
  // Dummy constructor for gcc 3.4 compatibility
  task_finder_derived_probe (): derived_probe (0, 0) { assert(0); }
};


struct task_finder_derived_probe_group: public generic_dpg<task_finder_derived_probe>
{
public:
  void emit_module_decls (systemtap_session& ) { }
  void emit_module_init (systemtap_session& s);
  void emit_module_exit (systemtap_session& s);

  // Whether or not to initialize the vma tracker
  bool need_vma_tracker;
};


void
task_finder_derived_probe_group::emit_module_init (systemtap_session& s)
{
  s.op->newline();
  if (need_vma_tracker)
    {
      s.op->newline() << "/* ---- vma tracker ---- */";
      s.op->newline() << "rc = _stp_vma_init();";
      s.op->newline();
    }

  s.op->newline() << "/* ---- task finder ---- */";
  s.op->newline() << "if (rc == 0) {";
  s.op->newline(1) << "rc = stap_start_task_finder();";

  s.op->newline() << "if (rc) {";
  s.op->newline(1) << "stap_stop_task_finder();";
  s.op->newline(-1) << "}";
  s.op->newline(-1) << "}";
}


void
task_finder_derived_probe_group::emit_module_exit (systemtap_session& s)
{
  s.op->newline();
  s.op->newline() << "/* ---- task finder ---- */";
  s.op->newline() << "stap_stop_task_finder();";
}


// Declare that task_finder is needed in this session
void
enable_task_finder(systemtap_session& s)
{
  if (! s.task_finder_derived_probes)
    {
      s.task_finder_derived_probes = new task_finder_derived_probe_group();
      s.task_finder_derived_probes->need_vma_tracker = false;
    }
}

// Declare that vma tracker is needed in this session,
// implies that the task_finder is needed.
void
enable_vma_tracker(systemtap_session& s)
{
  enable_task_finder(s);
  s.task_finder_derived_probes->need_vma_tracker = true;
}

// Whether the vma tracker is needed in this session.
bool
vma_tracker_enabled(systemtap_session& s)
{
  return (s.task_finder_derived_probes
	  && s.task_finder_derived_probes->need_vma_tracker);
}

/* vim: set sw=2 ts=8 cino=>4,n-2,{2,^-2,t0,(0,u0,w1,M1 : */