path: root/gcc/analyzer/program-state.cc

/* Classes for representing the state of interest at a given path of analysis.
   Copyright (C) 2019-2021 Free Software Foundation, Inc.
   Contributed by David Malcolm <dmalcolm@redhat.com>.

This file is part of GCC.

GCC is free software; you can redistribute it and/or modify it
under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3, or (at your option)
any later version.

GCC is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
General Public License for more details.

You should have received a copy of the GNU General Public License
along with GCC; see the file COPYING3.  If not see
<http://www.gnu.org/licenses/>.  */

#include "config.h"
#include "system.h"
#include "coretypes.h"
#include "tree.h"
#include "diagnostic-core.h"
#include "diagnostic.h"
#include "function.h"
#include "json.h"
#include "analyzer/analyzer.h"
#include "analyzer/analyzer-logging.h"
#include "analyzer/sm.h"
#include "sbitmap.h"
#include "bitmap.h"
#include "tristate.h"
#include "ordered-hash-map.h"
#include "selftest.h"
#include "analyzer/call-string.h"
#include "analyzer/program-point.h"
#include "analyzer/store.h"
#include "analyzer/region-model.h"
#include "analyzer/program-state.h"
#include "analyzer/constraint-manager.h"
#include "alloc-pool.h"
#include "fibonacci_heap.h"
#include "shortest-paths.h"
#include "diagnostic-event-id.h"
#include "analyzer/pending-diagnostic.h"
#include "analyzer/diagnostic-manager.h"
#include "cfg.h"
#include "basic-block.h"
#include "gimple.h"
#include "gimple-iterator.h"
#include "cgraph.h"
#include "digraph.h"
#include "analyzer/supergraph.h"
#include "analyzer/program-state.h"
#include "analyzer/exploded-graph.h"
#include "analyzer/state-purge.h"
#include "analyzer/analyzer-selftests.h"

#if ENABLE_ANALYZER

namespace ana {

/* class extrinsic_state.  */

/* Dump a multiline representation of this state to PP.  */

void
extrinsic_state::dump_to_pp (pretty_printer *pp) const
{
  pp_printf (pp, "extrinsic_state: %i checker(s)\n", get_num_checkers ());
  unsigned i;
  state_machine *checker;
  FOR_EACH_VEC_ELT (m_checkers, i, checker)
    {
      pp_printf (pp, "m_checkers[%i]: %qs\n", i, checker->get_name ());
      checker->dump_to_pp (pp);
    }
}

/* Dump a multiline representation of this state to OUTF.  */

void
extrinsic_state::dump_to_file (FILE *outf) const
{
  pretty_printer pp;
  if (outf == stderr)
    pp_show_color (&pp) = pp_show_color (global_dc->printer);
  pp.buffer->stream = outf;
  dump_to_pp (&pp);
  pp_flush (&pp);
}

/* Dump a multiline representation of this state to stderr.  */

DEBUG_FUNCTION void
extrinsic_state::dump () const
{
  dump_to_file (stderr);
}

/* Return a new json::object of the form
   {"checkers"  : array of objects, one for each state_machine}.  */

json::object *
extrinsic_state::to_json () const
{
  json::object *ext_state_obj = new json::object ();

  {
    json::array *checkers_arr = new json::array ();
    unsigned i;
    state_machine *sm;
    FOR_EACH_VEC_ELT (m_checkers, i, sm)
      checkers_arr->append (sm->to_json ());
    ext_state_obj->set ("checkers", checkers_arr);
  }

  return ext_state_obj;
}

/* Get the region_model_manager for this extrinsic_state.  */

region_model_manager *
extrinsic_state::get_model_manager () const
{
  if (m_engine)
    return m_engine->get_model_manager ();
  else
    return NULL; /* for selftests.  */
}

/* struct sm_state_map::entry_t.  */

int
sm_state_map::entry_t::cmp (const entry_t &entry_a, const entry_t &entry_b)
{
  gcc_assert (entry_a.m_state);
  gcc_assert (entry_b.m_state);
  if (int cmp_state = ((int)entry_a.m_state->get_id ()
		       - (int)entry_b.m_state->get_id ()))
    return cmp_state;
  if (entry_a.m_origin && entry_b.m_origin)
    return svalue::cmp_ptr (entry_a.m_origin, entry_b.m_origin);
  if (entry_a.m_origin)
    return 1;
  if (entry_b.m_origin)
    return -1;
  return 0;
}

/* class sm_state_map.  */

/* sm_state_map's ctor.  */

sm_state_map::sm_state_map (const state_machine &sm)
: m_sm (sm), m_map (), m_global_state (sm.get_start_state ())
{
}

/* Clone the sm_state_map.  */

sm_state_map *
sm_state_map::clone () const
{
  return new sm_state_map (*this);
}

/* Print this sm_state_map to PP.
   If MODEL is non-NULL, print representative tree values where
   available.  */

void
sm_state_map::print (const region_model *model,
		      bool simple, bool multiline,
		      pretty_printer *pp) const
{
  bool first = true;
  if (!multiline)
    pp_string (pp, "{");
  if (m_global_state != m_sm.get_start_state ())
    {
      if (multiline)
	pp_string (pp, "  ");
      pp_string (pp, "global: ");
      m_global_state->dump_to_pp (pp);
      if (multiline)
	pp_newline (pp);
      first = false;
    }
  auto_vec <const svalue *> keys (m_map.elements ());
  for (map_t::iterator iter = m_map.begin ();
       iter != m_map.end ();
       ++iter)
    keys.quick_push ((*iter).first);
  keys.qsort (svalue::cmp_ptr_ptr);
  unsigned i;
  const svalue *sval;
  FOR_EACH_VEC_ELT (keys, i, sval)
    {
      if (multiline)
	pp_string (pp, "  ");
      else if (!first)
	pp_string (pp, ", ");
      first = false;
      if (!flag_dump_noaddr)
	{
	  pp_pointer (pp, sval);
	  pp_string (pp, ": ");
	}
      sval->dump_to_pp (pp, simple);

      entry_t e = *const_cast <map_t &> (m_map).get (sval);
      pp_string (pp, ": ");
      e.m_state->dump_to_pp (pp);
      if (model)
	if (tree rep = model->get_representative_tree (sval))
	  {
	    pp_string (pp, " (");
	    dump_quoted_tree (pp, rep);
	    pp_character (pp, ')');
	  }
      if (e.m_origin)
	{
	  pp_string (pp, " (origin: ");
	  if (!flag_dump_noaddr)
	    {
	      pp_pointer (pp, e.m_origin);
	      pp_string (pp, ": ");
	    }
	  e.m_origin->dump_to_pp (pp, simple);
	  if (model)
	    if (tree rep = model->get_representative_tree (e.m_origin))
	      {
		pp_string (pp, " (");
		dump_quoted_tree (pp, rep);
		pp_character (pp, ')');
	      }
	  pp_string (pp, ")");
	}
      if (multiline)
	pp_newline (pp);
    }
  if (!multiline)
    pp_string (pp, "}");
}

/* Dump this object to stderr.  */

DEBUG_FUNCTION void
sm_state_map::dump (bool simple) const
{
  pretty_printer pp;
  pp_show_color (&pp) = pp_show_color (global_dc->printer);
  pp.buffer->stream = stderr;
  print (NULL, simple, true, &pp);
  pp_newline (&pp);
  pp_flush (&pp);
}

/* Return a new json::object of the form
   {"global"  : (optional) value for global state,
    SVAL_DESC : value for state}.  */

json::object *
sm_state_map::to_json () const
{
  json::object *map_obj = new json::object ();

  if (m_global_state != m_sm.get_start_state ())
    map_obj->set ("global", m_global_state->to_json ());
  for (map_t::iterator iter = m_map.begin ();
       iter != m_map.end ();
       ++iter)
    {
      const svalue *sval = (*iter).first;
      entry_t e = (*iter).second;

      label_text sval_desc = sval->get_desc ();
      map_obj->set (sval_desc.m_buffer, e.m_state->to_json ());
      sval_desc.maybe_free ();

      /* This doesn't yet JSONify e.m_origin.  */
    }
  return map_obj;
}

/* Return true if no states have been set within this map
   (all expressions are for the start state).  */

bool
sm_state_map::is_empty_p () const
{
  return m_map.elements () == 0 && m_global_state == m_sm.get_start_state ();
}

/* Generate a hash value for this sm_state_map.  */

hashval_t
sm_state_map::hash () const
{
  hashval_t result = 0;

  /* Accumulate the result by xoring a hash for each slot, so that the
     result doesn't depend on the ordering of the slots in the map.  */

  for (map_t::iterator iter = m_map.begin ();
       iter != m_map.end ();
       ++iter)
    {
      inchash::hash hstate;
      hstate.add_ptr ((*iter).first);
      entry_t e = (*iter).second;
      hstate.add_int (e.m_state->get_id ());
      hstate.add_ptr (e.m_origin);
      result ^= hstate.end ();
    }
  result ^= m_global_state->get_id ();

  return result;
}

/* Equality operator for sm_state_map.  */

bool
sm_state_map::operator== (const sm_state_map &other) const
{
  if (m_global_state != other.m_global_state)
    return false;

  if (m_map.elements () != other.m_map.elements ())
    return false;

  for (map_t::iterator iter = m_map.begin ();
       iter != m_map.end ();
       ++iter)
    {
      const svalue *sval = (*iter).first;
      entry_t e = (*iter).second;
      entry_t *other_slot = const_cast <map_t &> (other.m_map).get (sval);
      if (other_slot == NULL)
	return false;
      if (e != *other_slot)
	return false;
    }

  gcc_checking_assert (hash () == other.hash ());

  return true;
}

/* Get the state of SVAL within this object.
   States default to the start state.  */

state_machine::state_t
sm_state_map::get_state (const svalue *sval,
			  const extrinsic_state &ext_state) const
{
  gcc_assert (sval);

  sval = canonicalize_svalue (sval, ext_state);

  if (entry_t *slot
      = const_cast <map_t &> (m_map).get (sval))
    return slot->m_state;

  /* SVAL has no explicit sm-state.
     If this sm allows for state inheritance, then SVAL might have implicit
     sm-state inherited via a parent.
     For example INIT_VAL(foo.field) might inherit taintedness state from
     INIT_VAL(foo).  */
  if (m_sm.inherited_state_p ())
    if (region_model_manager *mgr = ext_state.get_model_manager ())
      if (const initial_svalue *init_sval = sval->dyn_cast_initial_svalue ())
	{
	  const region *reg = init_sval->get_region ();
	  /* Try recursing upwards (up to the base region for the cluster).  */
	  if (!reg->base_region_p ())
	    if (const region *parent_reg = reg->get_parent_region ())
	      {
		const svalue *parent_init_sval
		  = mgr->get_or_create_initial_value (parent_reg);
		state_machine::state_t parent_state
		  = get_state (parent_init_sval, ext_state);
		if (parent_state)
		  return parent_state;
	      }
	}

  return m_sm.get_default_state (sval);
}

/* Get the "origin" svalue for any state of SVAL.  */

const svalue *
sm_state_map::get_origin (const svalue *sval,
			   const extrinsic_state &ext_state) const
{
  gcc_assert (sval);

  sval = canonicalize_svalue (sval, ext_state);

  entry_t *slot
    = const_cast <map_t &> (m_map).get (sval);
  if (slot)
    return slot->m_origin;
  else
    return NULL;
}

/* Set the state of SID within MODEL to STATE, recording that
   the state came from ORIGIN.  */

void
sm_state_map::set_state (region_model *model,
			 const svalue *sval,
			 state_machine::state_t state,
			 const svalue *origin,
			 const extrinsic_state &ext_state)
{
  if (model == NULL)
    return;

  /* Reject attempts to set state on UNKNOWN.  */
  if (sval->get_kind () == SK_UNKNOWN)
    return;

  equiv_class &ec = model->get_constraints ()->get_equiv_class (sval);
  if (!set_state (ec, state, origin, ext_state))
    return;
}

/* Set the state of EC to STATE, recording that the state came from
   ORIGIN.
   Return true if any states of svalue_ids within EC changed.  */

bool
sm_state_map::set_state (const equiv_class &ec,
			 state_machine::state_t state,
			 const svalue *origin,
			 const extrinsic_state &ext_state)
{
  int i;
  const svalue *sval;
  bool any_changed = false;
  FOR_EACH_VEC_ELT (ec.m_vars, i, sval)
    any_changed |= impl_set_state (sval, state, origin, ext_state);
  return any_changed;
}

/* Set state of SVAL to STATE, bypassing equivalence classes.
   Return true if the state changed.  */

bool
sm_state_map::impl_set_state (const svalue *sval,
			      state_machine::state_t state,
			      const svalue *origin,
			      const extrinsic_state &ext_state)
{
  sval = canonicalize_svalue (sval, ext_state);

  if (get_state (sval, ext_state) == state)
    return false;

  /* Special-case state 0 as the default value.  */
  if (state == 0)
    {
      if (m_map.get (sval))
	m_map.remove (sval);
      return true;
    }
  gcc_assert (sval);
  m_map.put (sval, entry_t (state, origin));
  return true;
}

/* Set the "global" state within this state map to STATE.  */

void
sm_state_map::set_global_state (state_machine::state_t state)
{
  m_global_state = state;
}

/* Get the "global" state within this state map.  */

state_machine::state_t
sm_state_map::get_global_state () const
{
  return m_global_state;
}

/* Purge any state for SVAL.
   If !SM::can_purge_p, then report the state as leaking,
   using CTXT.  */

void
sm_state_map::on_svalue_leak (const svalue *sval,
			      impl_region_model_context *ctxt)
{
  if (state_machine::state_t state = get_state (sval, ctxt->m_ext_state))
    {
      if (!m_sm.can_purge_p (state))
	ctxt->on_state_leak (m_sm, sval, state);
      m_map.remove (sval);
    }
}

/* Purge any state for svalues that aren't live with respect to LIVE_SVALUES
   and MODEL.  */

void
sm_state_map::on_liveness_change (const svalue_set &live_svalues,
				  const region_model *model,
				  impl_region_model_context *ctxt)
{
  svalue_set svals_to_unset;

  auto_vec<const svalue *> leaked_svals (m_map.elements ());
  for (map_t::iterator iter = m_map.begin ();
       iter != m_map.end ();
       ++iter)
    {
      const svalue *iter_sval = (*iter).first;
      if (!iter_sval->live_p (live_svalues, model))
	{
	  svals_to_unset.add (iter_sval);
	  entry_t e = (*iter).second;
	  if (!m_sm.can_purge_p (e.m_state))
	    leaked_svals.quick_push (iter_sval);
	}
    }

  leaked_svals.qsort (svalue::cmp_ptr_ptr);

  unsigned i;
  const svalue *sval;
  FOR_EACH_VEC_ELT (leaked_svals, i, sval)
    {
      entry_t e = *m_map.get (sval);
      ctxt->on_state_leak (m_sm, sval, e.m_state);
    }

  for (svalue_set::iterator iter = svals_to_unset.begin ();
       iter != svals_to_unset.end (); ++iter)
    m_map.remove (*iter);
}

/* Purge state from SVAL (in response to a call to an unknown function).  */

void
sm_state_map::on_unknown_change (const svalue *sval,
				 bool is_mutable,
				 const extrinsic_state &ext_state)
{
  svalue_set svals_to_unset;

  for (map_t::iterator iter = m_map.begin ();
       iter != m_map.end ();
       ++iter)
    {
      const svalue *key = (*iter).first;
      entry_t e = (*iter).second;
      /* We only want to purge state for some states when things
	 are mutable.  For example, in sm-malloc.cc, an on-stack ptr
	 doesn't stop being stack-allocated when passed to an unknown fn.  */
      if (!m_sm.reset_when_passed_to_unknown_fn_p (e.m_state, is_mutable))
	continue;
      if (key == sval)
	svals_to_unset.add (key);
      /* If we have INIT_VAL(BASE_REG), then unset any INIT_VAL(REG)
	 for REG within BASE_REG.  */
      if (const initial_svalue *init_sval = sval->dyn_cast_initial_svalue ())
	if (const initial_svalue *init_key = key->dyn_cast_initial_svalue ())
	  {
	    const region *changed_reg = init_sval->get_region ();
	    const region *changed_key = init_key->get_region ();
	    if (changed_key->get_base_region () == changed_reg)
	      svals_to_unset.add (key);
	  }
    }

  for (svalue_set::iterator iter = svals_to_unset.begin ();
       iter != svals_to_unset.end (); ++iter)
    impl_set_state (*iter, (state_machine::state_t)0, NULL, ext_state);
}

/* Comparator for imposing an order on sm_state_map instances.  */

int
sm_state_map::cmp (const sm_state_map &smap_a, const sm_state_map &smap_b)
{
  if (int cmp_count = smap_a.elements () - smap_b.elements ())
    return cmp_count;

  auto_vec <const svalue *> keys_a (smap_a.elements ());
  for (map_t::iterator iter = smap_a.begin ();
       iter != smap_a.end ();
       ++iter)
    keys_a.quick_push ((*iter).first);
  keys_a.qsort (svalue::cmp_ptr_ptr);

  auto_vec <const svalue *> keys_b (smap_b.elements ());
  for (map_t::iterator iter = smap_b.begin ();
       iter != smap_b.end ();
       ++iter)
    keys_b.quick_push ((*iter).first);
  keys_b.qsort (svalue::cmp_ptr_ptr);

  unsigned i;
  const svalue *sval_a;
  FOR_EACH_VEC_ELT (keys_a, i, sval_a)
    {
      const svalue *sval_b = keys_b[i];
      if (int cmp_sval = svalue::cmp_ptr (sval_a, sval_b))
	return cmp_sval;
      const entry_t *e_a = const_cast <map_t &> (smap_a.m_map).get (sval_a);
      const entry_t *e_b = const_cast <map_t &> (smap_b.m_map).get (sval_b);
      if (int cmp_entry = entry_t::cmp (*e_a, *e_b))
	return cmp_entry;
    }

  return 0;
}

/* Canonicalize SVAL before getting/setting it within the map.
   Convert all NULL pointers to (void *) to avoid state explosions
   involving all of the various (foo *)NULL vs (bar *)NULL.  */

const svalue *
sm_state_map::canonicalize_svalue (const svalue *sval,
				   const extrinsic_state &ext_state)
{
  region_model_manager *mgr = ext_state.get_model_manager ();
  if (mgr && sval->get_type () && POINTER_TYPE_P (sval->get_type ()))
    if (tree cst = sval->maybe_get_constant ())
      if (zerop (cst))
	return mgr->get_or_create_constant_svalue (null_pointer_node);

  return sval;
}

/* class program_state.  */

/* program_state's ctor.  */

program_state::program_state (const extrinsic_state &ext_state)
: m_region_model (NULL),
  m_checker_states (ext_state.get_num_checkers ()),
  m_valid (true)
{
  engine *eng = ext_state.get_engine ();
  region_model_manager *mgr = eng->get_model_manager ();
  m_region_model = new region_model (mgr);
  const int num_states = ext_state.get_num_checkers ();
  for (int i = 0; i < num_states; i++)
    {
      sm_state_map *sm = new sm_state_map (ext_state.get_sm (i));
      m_checker_states.quick_push (sm);
    }
}

/* program_state's copy ctor.  */

program_state::program_state (const program_state &other)
: m_region_model (new region_model (*other.m_region_model)),
  m_checker_states (other.m_checker_states.length ()),
  m_valid (true)
{
  int i;
  sm_state_map *smap;
  FOR_EACH_VEC_ELT (other.m_checker_states, i, smap)
    m_checker_states.quick_push (smap->clone ());
}

/* program_state's assignment operator.  */

program_state&
program_state::operator= (const program_state &other)
{
  delete m_region_model;
  m_region_model = new region_model (*other.m_region_model);

  int i;
  sm_state_map *smap;
  FOR_EACH_VEC_ELT (m_checker_states, i, smap)
    delete smap;
  m_checker_states.truncate (0);
  gcc_assert (m_checker_states.space (other.m_checker_states.length ()));

  FOR_EACH_VEC_ELT (other.m_checker_states, i, smap)
    m_checker_states.quick_push (smap->clone ());

  m_valid = other.m_valid;

  return *this;
}

#if __cplusplus >= 201103
/* Move constructor for program_state (when building with C++11).  */
program_state::program_state (program_state &&other)
: m_region_model (other.m_region_model),
  m_checker_states (other.m_checker_states.length ())
{
  other.m_region_model = NULL;

  int i;
  sm_state_map *smap;
  FOR_EACH_VEC_ELT (other.m_checker_states, i, smap)
    m_checker_states.quick_push (smap);
  other.m_checker_states.truncate (0);

  m_valid = other.m_valid;
}
#endif

/* program_state's dtor.  */

program_state::~program_state ()
{
  delete m_region_model;
}

/* Generate a hash value for this program_state.  */

hashval_t
program_state::hash () const
{
  hashval_t result = m_region_model->hash ();

  int i;
  sm_state_map *smap;
  FOR_EACH_VEC_ELT (m_checker_states, i, smap)
    result ^= smap->hash ();
  return result;
}

/* Equality operator for program_state.
   All parts of the program_state (region model, checker states) must
   equal their counterparts in OTHER for the two program_states to be
   considered equal.  */

bool
program_state::operator== (const program_state &other) const
{
  if (!(*m_region_model == *other.m_region_model))
    return false;

  int i;
  sm_state_map *smap;
  FOR_EACH_VEC_ELT (m_checker_states, i, smap)
    if (!(*smap == *other.m_checker_states[i]))
      return false;

  gcc_checking_assert (hash () == other.hash ());

  return true;
}

/* Print a compact representation of this state to PP.  */

void
program_state::print (const extrinsic_state &ext_state,
		      pretty_printer *pp) const
{
  pp_printf (pp, "rmodel: ");
  m_region_model->dump_to_pp (pp, true, false);
  pp_newline (pp);

  int i;
  sm_state_map *smap;
  FOR_EACH_VEC_ELT (m_checker_states, i, smap)
    {
      if (!smap->is_empty_p ())
	{
	  pp_printf (pp, "%s: ", ext_state.get_name (i));
	  smap->print (m_region_model, true, false, pp);
	  pp_newline (pp);
	}
    }
  if (!m_valid)
    {
      pp_printf (pp, "invalid state");
      pp_newline (pp);
    }
}

/* Dump a representation of this state to PP.  */

void
program_state::dump_to_pp (const extrinsic_state &ext_state,
			   bool /*summarize*/, bool multiline,
			   pretty_printer *pp) const
{
  if (!multiline)
    pp_string (pp, "{");
  {
    pp_printf (pp, "rmodel:");
    if (multiline)
      pp_newline (pp);
    else
      pp_string (pp, " {");
    m_region_model->dump_to_pp (pp, true, multiline);
    if (!multiline)
      pp_string (pp, "}");
  }

  int i;
  sm_state_map *smap;
  FOR_EACH_VEC_ELT (m_checker_states, i, smap)
    {
      if (!smap->is_empty_p ())
	{
	  if (!multiline)
	    pp_string (pp, " {");
	  pp_printf (pp, "%s: ", ext_state.get_name (i));
	  if (multiline)
	    pp_newline (pp);
	  smap->print (m_region_model, true, multiline, pp);
	  if (!multiline)
	    pp_string (pp, "}");
	}
    }

  if (!m_valid)
    {
      if (!multiline)
	pp_space (pp);
      pp_printf (pp, "invalid state");
      if (multiline)
	pp_newline (pp);
    }
  if (!multiline)
    pp_string (pp, "}");
}

/* Dump a representation of this state to OUTF.  */

void
program_state::dump_to_file (const extrinsic_state &ext_state,
			     bool summarize, bool multiline,
			     FILE *outf) const
{
  pretty_printer pp;
  pp_format_decoder (&pp) = default_tree_printer;
  if (outf == stderr)
    pp_show_color (&pp) = pp_show_color (global_dc->printer);
  pp.buffer->stream = outf;
  dump_to_pp (ext_state, summarize, multiline, &pp);
  pp_flush (&pp);
}

/* Dump a multiline representation of this state to stderr.  */

DEBUG_FUNCTION void
program_state::dump (const extrinsic_state &ext_state,
		     bool summarize) const
{
  dump_to_file (ext_state, summarize, true, stderr);
}

/* Return a new json::object of the form
   {"store"  : object for store,
    "constraints" : object for constraint_manager,
    "curr_frame" : (optional) str for current frame,
    "checkers" : { STATE_NAME : object per sm_state_map },
    "valid" : true/false}.  */

json::object *
program_state::to_json (const extrinsic_state &ext_state) const
{
  json::object *state_obj = new json::object ();

  state_obj->set ("store", m_region_model->get_store ()->to_json ());
  state_obj->set ("constraints",
		  m_region_model->get_constraints ()->to_json ());
  if (m_region_model->get_current_frame ())
    state_obj->set ("curr_frame",
		    m_region_model->get_current_frame ()->to_json ());

  /* Provide m_checker_states as an object, using names as keys.  */
  {
    json::object *checkers_obj = new json::object ();

    int i;
    sm_state_map *smap;
    FOR_EACH_VEC_ELT (m_checker_states, i, smap)
      if (!smap->is_empty_p ())
	checkers_obj->set (ext_state.get_name (i), smap->to_json ());

    state_obj->set ("checkers", checkers_obj);
  }

  state_obj->set ("valid", new json::literal (m_valid));

  return state_obj;
}

/* Update this program_state to reflect a top-level call to FUN.
   The params will have initial_svalues.  */

void
program_state::push_frame (const extrinsic_state &ext_state ATTRIBUTE_UNUSED,
			   function *fun)
{
  m_region_model->push_frame (fun, NULL, NULL);
}

/* Get the current function of this state.  */

function *
program_state::get_current_function () const
{
  return m_region_model->get_current_function ();
}

/* Determine if following edge SUCC from ENODE is valid within the graph EG
   and update this state accordingly in-place.

   Return true if the edge can be followed, or false otherwise.

   Check for relevant conditionals and switch-values for conditionals
   and switch statements, adding the relevant conditions to this state.
   Push/pop frames for interprocedural edges and update params/returned
   values.

   This is the "state" half of exploded_node::on_edge.  */

bool
program_state::on_edge (exploded_graph &eg,
			const exploded_node &enode,
			const superedge *succ)
{
  /* Update state.  */
  const program_point &point = enode.get_point ();
  const gimple *last_stmt = point.get_supernode ()->get_last_stmt ();

  /* For conditionals and switch statements, add the
     relevant conditions (for the specific edge) to new_state;
     skip edges for which the resulting constraints
     are impossible.
     This also updates frame information for call/return superedges.
     Adding the relevant conditions for the edge could also trigger
     sm-state transitions (e.g. transitions due to ptrs becoming known
     to be NULL or non-NULL) */

  impl_region_model_context ctxt (eg, &enode,
				  &enode.get_state (),
				  this,
				  last_stmt);
  if (!m_region_model->maybe_update_for_edge (*succ,
					      last_stmt,
					      &ctxt, NULL))
    {
      logger * const logger = eg.get_logger ();
      if (logger)
	logger->log ("edge to SN: %i is impossible"
		     " due to region_model constraints",
		     succ->m_dest->m_index);
      return false;
    }

  program_state::detect_leaks (enode.get_state (), *this,
				NULL, eg.get_ext_state (),
				&ctxt);

  return true;
}

/* Generate a simpler version of THIS, discarding state that's no longer
   relevant at POINT.
   The idea is that we're more likely to be able to consolidate
   multiple (point, state) into single exploded_nodes if we discard
   irrelevant state (e.g. at the end of functions).  */

program_state
program_state::prune_for_point (exploded_graph &eg,
				const program_point &point,
				const exploded_node *enode_for_diag) const
{
  logger * const logger = eg.get_logger ();
  LOG_SCOPE (logger);

  function *fun = point.get_function ();
  if (!fun)
    return *this;

  program_state new_state (*this);

  const state_purge_map *pm = eg.get_purge_map ();
  if (pm)
    {
      unsigned num_ssas_purged = 0;
      auto_vec<const decl_region *> ssa_name_regs;
      new_state.m_region_model->get_ssa_name_regions_for_current_frame
	(&ssa_name_regs);
      ssa_name_regs.qsort (region::cmp_ptr_ptr);
      unsigned i;
      const decl_region *reg;
      FOR_EACH_VEC_ELT (ssa_name_regs, i, reg)
	{
	  tree ssa_name = reg->get_decl ();
	  const state_purge_per_ssa_name &per_ssa
	    = pm->get_data_for_ssa_name (ssa_name);
	  if (!per_ssa.needed_at_point_p (point.get_function_point ()))
	    {
	      /* Don't purge bindings of SSA names to svalues
		 that have unpurgable sm-state, so that leaks are
		 reported at the end of the function, rather than
		 at the last place that such an SSA name is referred to.

		 But do purge them for temporaries (when SSA_NAME_VAR is
		 NULL), so that we report for cases where a leak happens when
		 a variable is overwritten with another value, so that the leak
		 is reported at the point of overwrite, rather than having
		 temporaries keep the value reachable until the frame is
		 popped.  */
	      const svalue *sval
		= new_state.m_region_model->get_store_value (reg);
	      if (!new_state.can_purge_p (eg.get_ext_state (), sval)
		  && SSA_NAME_VAR (ssa_name))
		{
		  /* (currently only state maps can keep things
		     alive).  */
		  if (logger)
		    logger->log ("not purging binding for %qE"
				 " (used by state map)", ssa_name);
		  continue;
		}

	      new_state.m_region_model->purge_region (reg);
	      num_ssas_purged++;
	    }
	}

      if (num_ssas_purged > 0)
	{
	  if (logger)
	    logger->log ("num_ssas_purged: %i", num_ssas_purged);
	  impl_region_model_context ctxt (eg, enode_for_diag,
					  this,
					  &new_state,
					  point.get_stmt ());
	  detect_leaks (*this, new_state, NULL, eg.get_ext_state (), &ctxt);
	}
    }

  new_state.m_region_model->canonicalize ();

  return new_state;
}

/* Get a representative tree to use for describing SVAL.  */

tree
program_state::get_representative_tree (const svalue *sval) const
{
  gcc_assert (m_region_model);
  return m_region_model->get_representative_tree (sval);
}

/* Attempt to merge this state with OTHER, both at POINT.
   Write the result to *OUT.
   If the states were merged successfully, return true.  */

bool
program_state::can_merge_with_p (const program_state &other,
				 const program_point &point,
				 program_state *out) const
{
  gcc_assert (out);
  gcc_assert (m_region_model);

  /* Early reject if there are sm-differences between the states.  */
  int i;
  sm_state_map *smap;
  FOR_EACH_VEC_ELT (out->m_checker_states, i, smap)
    if (*m_checker_states[i] != *other.m_checker_states[i])
      return false;

  /* Attempt to merge the region_models.  */
  if (!m_region_model->can_merge_with_p (*other.m_region_model,
					  point,
					  out->m_region_model))
    return false;

  /* Copy m_checker_states to OUT.  */
  FOR_EACH_VEC_ELT (out->m_checker_states, i, smap)
    {
      delete smap;
      out->m_checker_states[i] = m_checker_states[i]->clone ();
    }

  out->m_region_model->canonicalize ();

  return true;
}

/* Assert that this object is valid.  */

void
program_state::validate (const extrinsic_state &ext_state) const
{
  /* Skip this in a release build.  */
#if !CHECKING_P
  return;
#endif

  gcc_assert (m_checker_states.length () == ext_state.get_num_checkers ());
}

static void
log_set_of_svalues (logger *logger, const char *name,
		    const svalue_set &set)
{
  logger->log (name);
  logger->inc_indent ();
  auto_vec<const svalue *> sval_vecs (set.elements ());
  for (svalue_set::iterator iter = set.begin ();
       iter != set.end (); ++iter)
    sval_vecs.quick_push (*iter);
  sval_vecs.qsort (svalue::cmp_ptr_ptr);
  unsigned i;
  const svalue *sval;
  FOR_EACH_VEC_ELT (sval_vecs, i, sval)
    {
      logger->start_log_line ();
      pretty_printer *pp = logger->get_printer ();
      if (!flag_dump_noaddr)
	{
	  pp_pointer (pp, sval);
	  pp_string (pp, ": ");
	}
      sval->dump_to_pp (pp, false);
      logger->end_log_line ();
    }
  logger->dec_indent ();
}

/* Compare the sets of svalues reachable from each of SRC_STATE and DEST_STATE.
   For all svalues that are reachable in SRC_STATE and are not live in
   DEST_STATE (whether explicitly reachable in DEST_STATE, or implicitly live
   based on the former set), call CTXT->on_svalue_leak for them.

   Call on_liveness_change on both the CTXT and on the DEST_STATE's
   constraint_manager, purging dead svalues from sm-state and from
   constraints, respectively.

   This function should be called at each fine-grained state change, not
   just at exploded edges.  */

void
program_state::detect_leaks (const program_state &src_state,
			     const program_state &dest_state,
			     const svalue *extra_sval,
			     const extrinsic_state &ext_state,
			     region_model_context *ctxt)
{
  logger *logger = ext_state.get_logger ();
  LOG_SCOPE (logger);
  if (logger)
    {
      pretty_printer *pp = logger->get_printer ();
      logger->start_log_line ();
      pp_string (pp, "src_state: ");
      src_state.dump_to_pp (ext_state, true, false, pp);
      logger->end_log_line ();
      logger->start_log_line ();
      pp_string (pp, "dest_state: ");
      dest_state.dump_to_pp (ext_state, true, false, pp);
      logger->end_log_line ();
      if (extra_sval)
	{
	  logger->start_log_line ();
	  pp_string (pp, "extra_sval: ");
	  extra_sval->dump_to_pp (pp, true);
	  logger->end_log_line ();
	}
    }

  /* Get svalues reachable from each of src_state and dst_state.  */
  svalue_set src_svalues;
  svalue_set dest_svalues;
  src_state.m_region_model->get_reachable_svalues (&src_svalues, NULL);
  dest_state.m_region_model->get_reachable_svalues (&dest_svalues, extra_sval);

  if (logger)
    {
      log_set_of_svalues (logger, "src_state reachable svalues:", src_svalues);
      log_set_of_svalues (logger, "dest_state reachable svalues:",
			  dest_svalues);
    }

  auto_vec <const svalue *> dead_svals (src_svalues.elements ());
  for (svalue_set::iterator iter = src_svalues.begin ();
       iter != src_svalues.end (); ++iter)
    {
      const svalue *sval = (*iter);
      /* For each sval reachable from SRC_STATE, determine if it is
	 live in DEST_STATE: either explicitly reachable, or implicitly
	 live based on the set of explicitly reachable svalues.
	 Record those that have ceased to be live.  */
      if (!sval->live_p (dest_svalues, dest_state.m_region_model))
	dead_svals.quick_push (sval);
    }

  /* Call CTXT->on_svalue_leak on all svals in SRC_STATE  that have ceased
     to be live, sorting them first to ensure deterministic behavior.  */
  dead_svals.qsort (svalue::cmp_ptr_ptr);
  unsigned i;
  const svalue *sval;
  FOR_EACH_VEC_ELT (dead_svals, i, sval)
    ctxt->on_svalue_leak (sval);

  /* Purge dead svals from sm-state.  */
  ctxt->on_liveness_change (dest_svalues, dest_state.m_region_model);

  /* Purge dead svals from constraints.  */
  dest_state.m_region_model->get_constraints ()->on_liveness_change
    (dest_svalues, dest_state.m_region_model);
}

#if CHECKING_P

namespace selftest {

/* Tests for sm_state_map.  */

static void
test_sm_state_map ()
{
  tree x = build_global_decl ("x", integer_type_node);
  tree y = build_global_decl ("y", integer_type_node);
  tree z = build_global_decl ("z", integer_type_node);

  state_machine *sm = make_malloc_state_machine (NULL);
  auto_delete_vec <state_machine> checkers;
  checkers.safe_push (sm);
  engine eng;
  extrinsic_state ext_state (checkers, &eng);
  state_machine::state_t start = sm->get_start_state ();

  /* Test setting states on svalue_id instances directly.  */
  {
    const state_machine::state test_state_42 ("test state 42", 42);
    const state_machine::state_t TEST_STATE_42 = &test_state_42;
    region_model_manager mgr;
    region_model model (&mgr);
    const svalue *x_sval = model.get_rvalue (x, NULL);
    const svalue *y_sval = model.get_rvalue (y, NULL);
    const svalue *z_sval = model.get_rvalue (z, NULL);

    sm_state_map map (*sm);
    ASSERT_TRUE (map.is_empty_p ());
    ASSERT_EQ (map.get_state (x_sval, ext_state), start);

    map.impl_set_state (x_sval, TEST_STATE_42, z_sval, ext_state);
    ASSERT_EQ (map.get_state (x_sval, ext_state), TEST_STATE_42);
    ASSERT_EQ (map.get_origin (x_sval, ext_state), z_sval);
    ASSERT_EQ (map.get_state (y_sval, ext_state), start);
    ASSERT_FALSE (map.is_empty_p ());

    map.impl_set_state (y_sval, 0, z_sval, ext_state);
    ASSERT_EQ (map.get_state (y_sval, ext_state), start);

    map.impl_set_state (x_sval, 0, z_sval, ext_state);
    ASSERT_EQ (map.get_state (x_sval, ext_state), start);
    ASSERT_TRUE (map.is_empty_p ());
  }

  const state_machine::state test_state_5 ("test state 5", 5);
  const state_machine::state_t TEST_STATE_5 = &test_state_5;

  /* Test setting states via equivalence classes.  */
  {
    region_model_manager mgr;
    region_model model (&mgr);
    const svalue *x_sval = model.get_rvalue (x, NULL);
    const svalue *y_sval = model.get_rvalue (y, NULL);
    const svalue *z_sval = model.get_rvalue (z, NULL);

    sm_state_map map (*sm);
    ASSERT_TRUE (map.is_empty_p ());
    ASSERT_EQ (map.get_state (x_sval, ext_state), start);
    ASSERT_EQ (map.get_state (y_sval, ext_state), start);

    model.add_constraint (x, EQ_EXPR, y, NULL);

    /* Setting x to a state should also update y, as they
       are in the same equivalence class.  */
    map.set_state (&model, x_sval, TEST_STATE_5, z_sval, ext_state);
    ASSERT_EQ (map.get_state (x_sval, ext_state), TEST_STATE_5);
    ASSERT_EQ (map.get_state (y_sval, ext_state), TEST_STATE_5);
    ASSERT_EQ (map.get_origin (x_sval, ext_state), z_sval);
    ASSERT_EQ (map.get_origin (y_sval, ext_state), z_sval);
  }

  /* Test equality and hashing.  */
  {
    region_model_manager mgr;
    region_model model (&mgr);
    const svalue *y_sval = model.get_rvalue (y, NULL);
    const svalue *z_sval = model.get_rvalue (z, NULL);

    sm_state_map map0 (*sm);
    sm_state_map map1 (*sm);
    sm_state_map map2 (*sm);

    ASSERT_EQ (map0.hash (), map1.hash ());
    ASSERT_EQ (map0, map1);

    map1.impl_set_state (y_sval, TEST_STATE_5, z_sval, ext_state);
    ASSERT_NE (map0.hash (), map1.hash ());
    ASSERT_NE (map0, map1);

    /* Make the same change to map2.  */
    map2.impl_set_state (y_sval, TEST_STATE_5, z_sval, ext_state);
    ASSERT_EQ (map1.hash (), map2.hash ());
    ASSERT_EQ (map1, map2);
  }

  /* Equality and hashing shouldn't depend on ordering.  */
  {
    const state_machine::state test_state_2 ("test state 2", 2);
    const state_machine::state_t TEST_STATE_2 = &test_state_2;
    const state_machine::state test_state_3 ("test state 3", 3);
    const state_machine::state_t TEST_STATE_3 = &test_state_3;
    sm_state_map map0 (*sm);
    sm_state_map map1 (*sm);
    sm_state_map map2 (*sm);

    ASSERT_EQ (map0.hash (), map1.hash ());
    ASSERT_EQ (map0, map1);

    region_model_manager mgr;
    region_model model (&mgr);
    const svalue *x_sval = model.get_rvalue (x, NULL);
    const svalue *y_sval = model.get_rvalue (y, NULL);
    const svalue *z_sval = model.get_rvalue (z, NULL);

    map1.impl_set_state (x_sval, TEST_STATE_2, NULL, ext_state);
    map1.impl_set_state (y_sval, TEST_STATE_3, NULL, ext_state);
    map1.impl_set_state (z_sval, TEST_STATE_2, NULL, ext_state);

    map2.impl_set_state (z_sval, TEST_STATE_2, NULL, ext_state);
    map2.impl_set_state (y_sval, TEST_STATE_3, NULL, ext_state);
    map2.impl_set_state (x_sval, TEST_STATE_2, NULL, ext_state);

    ASSERT_EQ (map1.hash (), map2.hash ());
    ASSERT_EQ (map1, map2);
  }

  // TODO: coverage for purging
}

/* Check program_state works as expected.  */

static void
test_program_state_1 ()
{
  /* Create a program_state for a global ptr "p" that has
     malloc sm-state, pointing to a region on the heap.  */
  tree p = build_global_decl ("p", ptr_type_node);

  state_machine *sm = make_malloc_state_machine (NULL);
  const state_machine::state_t UNCHECKED_STATE
    = sm->get_state_by_name ("unchecked");
  auto_delete_vec <state_machine> checkers;
  checkers.safe_push (sm);

  engine eng;
  extrinsic_state ext_state (checkers, &eng);
  region_model_manager *mgr = eng.get_model_manager ();
  program_state s (ext_state);
  region_model *model = s.m_region_model;
  const svalue *size_in_bytes
    = mgr->get_or_create_unknown_svalue (integer_type_node);
  const region *new_reg = model->create_region_for_heap_alloc (size_in_bytes);
  const svalue *ptr_sval = mgr->get_ptr_svalue (ptr_type_node, new_reg);
  model->set_value (model->get_lvalue (p, NULL),
		    ptr_sval, NULL);
  sm_state_map *smap = s.m_checker_states[0];

  smap->impl_set_state (ptr_sval, UNCHECKED_STATE, NULL, ext_state);
  ASSERT_EQ (smap->get_state (ptr_sval, ext_state), UNCHECKED_STATE);
}

/* Check that program_state works for string literals.  */

static void
test_program_state_2 ()
{
  /* Create a program_state for a global ptr "p" that points to
     a string constant.  */
  tree p = build_global_decl ("p", ptr_type_node);

  tree string_cst_ptr = build_string_literal (4, "foo");

  auto_delete_vec <state_machine> checkers;
  engine eng;
  extrinsic_state ext_state (checkers, &eng);

  program_state s (ext_state);
  region_model *model = s.m_region_model;
  const region *p_reg = model->get_lvalue (p, NULL);
  const svalue *str_sval = model->get_rvalue (string_cst_ptr, NULL);
  model->set_value (p_reg, str_sval, NULL);
}

/* Verify that program_states with identical sm-state can be merged,
   and that the merged program_state preserves the sm-state.  */

static void
test_program_state_merging ()
{
  /* Create a program_state for a global ptr "p" that has
     malloc sm-state, pointing to a region on the heap.  */
  tree p = build_global_decl ("p", ptr_type_node);

  program_point point (program_point::origin ());
  auto_delete_vec <state_machine> checkers;
  checkers.safe_push (make_malloc_state_machine (NULL));
  engine eng;
  extrinsic_state ext_state (checkers, &eng);
  region_model_manager *mgr = eng.get_model_manager ();

  program_state s0 (ext_state);
  impl_region_model_context ctxt (&s0, ext_state);

  region_model *model0 = s0.m_region_model;
  const svalue *size_in_bytes
    = mgr->get_or_create_unknown_svalue (integer_type_node);
  const region *new_reg = model0->create_region_for_heap_alloc (size_in_bytes);
  const svalue *ptr_sval = mgr->get_ptr_svalue (ptr_type_node, new_reg);
  model0->set_value (model0->get_lvalue (p, &ctxt),
		     ptr_sval, &ctxt);
  sm_state_map *smap = s0.m_checker_states[0];
  const state_machine::state test_state ("test state", 0);
  const state_machine::state_t TEST_STATE = &test_state;
  smap->impl_set_state (ptr_sval, TEST_STATE, NULL, ext_state);
  ASSERT_EQ (smap->get_state (ptr_sval, ext_state), TEST_STATE);

  model0->canonicalize ();

  /* Verify that canonicalization preserves sm-state.  */
  ASSERT_EQ (smap->get_state (model0->get_rvalue (p, NULL), ext_state),
	     TEST_STATE);

  /* Make a copy of the program_state.  */
  program_state s1 (s0);
  ASSERT_EQ (s0, s1);

  /* We have two identical states with "p" pointing to a heap region
     with the given sm-state.
     They ought to be mergeable, preserving the sm-state.  */
  program_state merged (ext_state);
  ASSERT_TRUE (s0.can_merge_with_p (s1, point, &merged));
  merged.validate (ext_state);

  /* Verify that the merged state has the sm-state for "p".  */
  region_model *merged_model = merged.m_region_model;
  sm_state_map *merged_smap = merged.m_checker_states[0];
  ASSERT_EQ (merged_smap->get_state (merged_model->get_rvalue (p, NULL),
				     ext_state),
	     TEST_STATE);

  /* Try canonicalizing.  */
  merged.m_region_model->canonicalize ();
  merged.validate (ext_state);

  /* Verify that the merged state still has the sm-state for "p".  */
  ASSERT_EQ (merged_smap->get_state (merged_model->get_rvalue (p, NULL),
				     ext_state),
	     TEST_STATE);

  /* After canonicalization, we ought to have equality with the inputs.  */
  ASSERT_EQ (s0, merged);
}

/* Verify that program_states with different global-state in an sm-state
   can't be merged.  */

static void
test_program_state_merging_2 ()
{
  program_point point (program_point::origin ());
  auto_delete_vec <state_machine> checkers;
  checkers.safe_push (make_signal_state_machine (NULL));
  engine eng;
  extrinsic_state ext_state (checkers, &eng);

  const state_machine::state test_state_0 ("test state 0", 0);
  const state_machine::state test_state_1 ("test state 1", 1);
  const state_machine::state_t TEST_STATE_0 = &test_state_0;
  const state_machine::state_t TEST_STATE_1 = &test_state_1;

  program_state s0 (ext_state);
  {
    sm_state_map *smap0 = s0.m_checker_states[0];
    smap0->set_global_state (TEST_STATE_0);
    ASSERT_EQ (smap0->get_global_state (), TEST_STATE_0);
  }

  program_state s1 (ext_state);
  {
    sm_state_map *smap1 = s1.m_checker_states[0];
    smap1->set_global_state (TEST_STATE_1);
    ASSERT_EQ (smap1->get_global_state (), TEST_STATE_1);
  }

  ASSERT_NE (s0, s1);

  /* They ought to not be mergeable.  */
  program_state merged (ext_state);
  ASSERT_FALSE (s0.can_merge_with_p (s1, point, &merged));
}

/* Run all of the selftests within this file.  */

void
analyzer_program_state_cc_tests ()
{
  test_sm_state_map ();
  test_program_state_1 ();
  test_program_state_2 ();
  test_program_state_merging ();
  test_program_state_merging_2 ();
}

} // namespace selftest

#endif /* CHECKING_P */

} // namespace ana

#endif /* #if ENABLE_ANALYZER */