gcc/analyzer/checker-path.cc

/* Subclasses of diagnostic_path and diagnostic_event for analyzer diagnostics.
   Copyright (C) 2019-2022 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 "function.h"
#include "basic-block.h"
#include "gimple.h"
#include "gimple-pretty-print.h"
#include "fold-const.h"
#include "function.h"
#include "diagnostic-path.h"
#include "options.h"
#include "cgraph.h"
#include "function.h"
#include "cfg.h"
#include "digraph.h"
#include "alloc-pool.h"
#include "fibonacci_heap.h"
#include "diagnostic-event-id.h"
#include "shortest-paths.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/checker-path.h"
#include "gimple-iterator.h"
#include "analyzer/supergraph.h"
#include "analyzer/pending-diagnostic.h"
#include "analyzer/diagnostic-manager.h"
#include "analyzer/constraint-manager.h"
#include "analyzer/diagnostic-manager.h"
#include "analyzer/checker-path.h"
#include "analyzer/exploded-graph.h"

#if ENABLE_ANALYZER

namespace ana {

/* Get a string for EK.  */

const char *
event_kind_to_string (enum event_kind ek)
{
  switch (ek)
    {
    default:
      gcc_unreachable ();
    case EK_DEBUG:
      return "EK_DEBUG";
    case EK_CUSTOM:
      return "EK_CUSTOM";
    case EK_STMT:
      return "EK_STMT";
    case EK_REGION_CREATION:
      return "EK_REGION_CREATION";
    case EK_FUNCTION_ENTRY:
      return "EK_FUNCTION_ENTRY";
    case EK_STATE_CHANGE:
      return "EK_STATE_CHANGE";
    case EK_START_CFG_EDGE:
      return "EK_START_CFG_EDGE";
    case EK_END_CFG_EDGE:
      return "EK_END_CFG_EDGE";
    case EK_CALL_EDGE:
      return "EK_CALL_EDGE";
    case EK_RETURN_EDGE:
      return "EK_RETURN_EDGE";
    case EK_START_CONSOLIDATED_CFG_EDGES:
      return "EK_START_CONSOLIDATED_CFG_EDGES";
    case EK_END_CONSOLIDATED_CFG_EDGES:
      return "EK_END_CONSOLIDATED_CFG_EDGES";
    case EK_SETJMP:
      return "EK_SETJMP";
    case EK_REWIND_FROM_LONGJMP:
      return "EK_REWIND_FROM_LONGJMP";
    case EK_REWIND_TO_SETJMP:
      return "EK_REWIND_TO_SETJMP";
    case EK_WARNING:
      return "EK_WARNING";
    }
}

/* class checker_event : public diagnostic_event.  */

/* Dump this event to PP (for debugging/logging purposes).  */

void
checker_event::dump (pretty_printer *pp) const
{
  label_text event_desc (get_desc (false));
  pp_printf (pp, "\"%s\" (depth %i, m_loc=%x)",
	     event_desc.m_buffer,
	     get_stack_depth (),
	     get_location ());
  event_desc.maybe_free ();
}

/* Hook for being notified when this event has its final id EMISSION_ID
   and is about to emitted for PD.

   Base implementation of checker_event::prepare_for_emission vfunc;
   subclasses that override this should chain up to it.

   Record PD and EMISSION_ID, and call the get_desc vfunc, so that any
   side-effects of the call to get_desc take place before
   pending_diagnostic::emit is called.

   For example, state_change_event::get_desc can call
   pending_diagnostic::describe_state_change; free_of_non_heap can use this
   to tweak the message (TODO: would be neater to simply capture the
   pertinent data within the sm-state).  */

void
checker_event::prepare_for_emission (checker_path *,
				     pending_diagnostic *pd,
				     diagnostic_event_id_t emission_id)
{
  m_pending_diagnostic = pd;
  m_emission_id = emission_id;

  label_text desc = get_desc (false);
  desc.maybe_free ();
}

/* class debug_event : public checker_event.  */

/* Implementation of diagnostic_event::get_desc vfunc for
   debug_event.
   Use the saved string as the event's description.  */

label_text
debug_event::get_desc (bool) const
{
  return label_text::borrow (m_desc);
}

/* class precanned_custom_event : public custom_event.  */

/* Implementation of diagnostic_event::get_desc vfunc for
   precanned_custom_event.
   Use the saved string as the event's description.  */

label_text
precanned_custom_event::get_desc (bool) const
{
  return label_text::borrow (m_desc);
}

/* class statement_event : public checker_event.  */

/* statement_event's ctor.  */

statement_event::statement_event (const gimple *stmt, tree fndecl, int depth,
				  const program_state &dst_state)
: checker_event (EK_STMT, gimple_location (stmt), fndecl, depth),
  m_stmt (stmt),
  m_dst_state (dst_state)
{
}

/* Implementation of diagnostic_event::get_desc vfunc for
   statement_event.
   Use the statement's dump form as the event's description.  */

label_text
statement_event::get_desc (bool) const
{
  pretty_printer pp;
  pp_string (&pp, "stmt: ");
  pp_gimple_stmt_1 (&pp, m_stmt, 0, (dump_flags_t)0);
  return label_text::take (xstrdup (pp_formatted_text (&pp)));
}

/* class region_creation_event : public checker_event.  */

region_creation_event::region_creation_event (const region *reg,
					      location_t loc,
					      tree fndecl,
					      int depth)
: checker_event (EK_REGION_CREATION, loc, fndecl, depth),
  m_reg (reg)
{
}

/* Implementation of diagnostic_event::get_desc vfunc for
   region_creation_event.  */

label_text
region_creation_event::get_desc (bool) const
{
  switch (m_reg->get_memory_space ())
    {
    default:
      return label_text::borrow ("region created here");
    case MEMSPACE_STACK:
      return label_text::borrow ("region created on stack here");
    case MEMSPACE_HEAP:
      return label_text::borrow ("region created on heap here");
    }
}

/* class function_entry_event : public checker_event.  */

/* Implementation of diagnostic_event::get_desc vfunc for
   function_entry_event.

   Use a string such as "entry to 'foo'" as the event's description.  */

label_text
function_entry_event::get_desc (bool can_colorize) const
{
  return make_label_text (can_colorize, "entry to %qE", m_fndecl);
}

/* class state_change_event : public checker_event.  */

/* state_change_event's ctor.  */

state_change_event::state_change_event (const supernode *node,
					const gimple *stmt,
					int stack_depth,
					const state_machine &sm,
					const svalue *sval,
					state_machine::state_t from,
					state_machine::state_t to,
					const svalue *origin,
					const program_state &dst_state)
: checker_event (EK_STATE_CHANGE,
		 stmt->location, node->m_fun->decl,
		 stack_depth),
  m_node (node), m_stmt (stmt), m_sm (sm),
  m_sval (sval), m_from (from), m_to (to),
  m_origin (origin),
  m_dst_state (dst_state)
{
}

/* Implementation of diagnostic_event::get_desc vfunc for
   state_change_event.

   Attempt to generate a nicer human-readable description.
   For greatest precision-of-wording, give the pending diagnostic
   a chance to describe this state change (in terms of the
   diagnostic).
   Note that we only have a pending_diagnostic set on the event once
   the diagnostic is about to being emitted, so the description for
   an event can change.  */

label_text
state_change_event::get_desc (bool can_colorize) const
{
  if (m_pending_diagnostic)
    {
      region_model *model = m_dst_state.m_region_model;
      tree var = model->get_representative_tree (m_sval);
      tree origin = model->get_representative_tree (m_origin);
      label_text custom_desc
	= m_pending_diagnostic->describe_state_change
	    (evdesc::state_change (can_colorize, var, origin,
				   m_from, m_to, m_emission_id, *this));
      if (custom_desc.m_buffer)
	{
	  if (flag_analyzer_verbose_state_changes)
	    {
	      /* Append debug version.  */
	      label_text result;
	      if (m_origin)
		result = make_label_text
		  (can_colorize,
		   "%s (state of %qE: %qs -> %qs, origin: %qE)",
		   custom_desc.m_buffer,
		   var,
		   m_from->get_name (),
		   m_to->get_name (),
		   origin);
	      else
		result = make_label_text
		  (can_colorize,
		   "%s (state of %qE: %qs -> %qs, NULL origin)",
		   custom_desc.m_buffer,
		   var,
		   m_from->get_name (),
		   m_to->get_name ());
	      custom_desc.maybe_free ();
	      return result;
	    }
	  else
	    return custom_desc;
	}
    }

  /* Fallback description.  */
  if (m_sval)
    {
      label_text sval_desc = m_sval->get_desc ();
      if (m_origin)
	{
	  label_text origin_desc = m_origin->get_desc ();
	  return make_label_text
	    (can_colorize,
	     "state of %qs: %qs -> %qs (origin: %qs)",
	     sval_desc.m_buffer,
	     m_from->get_name (),
	     m_to->get_name (),
	     origin_desc.m_buffer);
	}
      else
	return make_label_text
	  (can_colorize,
	   "state of %qs: %qs -> %qs (NULL origin)",
	   sval_desc.m_buffer,
	   m_from->get_name (),
	   m_to->get_name ());
    }
  else
    {
      gcc_assert (m_origin == NULL);
      return make_label_text
	(can_colorize,
	 "global state: %qs -> %qs",
	 m_from->get_name (),
	 m_to->get_name ());
    }
}

/* class superedge_event : public checker_event.  */

/* Get the callgraph_superedge for this superedge_event, which must be
   for an interprocedural edge, rather than a CFG edge.  */

const callgraph_superedge&
superedge_event::get_callgraph_superedge () const
{
  gcc_assert (m_sedge->m_kind != SUPEREDGE_CFG_EDGE);
  return *m_sedge->dyn_cast_callgraph_superedge ();
}

/* Determine if this event should be filtered at the given verbosity
   level.  */

bool
superedge_event::should_filter_p (int verbosity) const
{
  switch (m_sedge->m_kind)
    {
    case SUPEREDGE_CFG_EDGE:
      {
	if (verbosity < 2)
	  return true;

	if (verbosity < 4)
	  {
	    /* Filter events with empty descriptions.  This ought to filter
	       FALLTHRU, but retain true/false/switch edges.  */
	    label_text desc = get_desc (false);
	    gcc_assert (desc.m_buffer);
	    if (desc.m_buffer[0] == '\0')
	      return true;
	    desc.maybe_free ();
	  }
      }
      break;

    default:
      break;
    }
  return false;
}

/* superedge_event's ctor.  */

superedge_event::superedge_event (enum event_kind kind,
				  const exploded_edge &eedge,
				  location_t loc, tree fndecl, int depth)
: checker_event (kind, loc, fndecl, depth),
  m_eedge (eedge), m_sedge (eedge.m_sedge),
  m_var (NULL_TREE), m_critical_state (0)
{
}

/* class cfg_edge_event : public superedge_event.  */

/* Get the cfg_superedge for this cfg_edge_event.  */

const cfg_superedge &
cfg_edge_event::get_cfg_superedge () const
{
  return *m_sedge->dyn_cast_cfg_superedge ();
}

/* cfg_edge_event's ctor.  */

cfg_edge_event::cfg_edge_event (enum event_kind kind,
				const exploded_edge &eedge,
				location_t loc, tree fndecl, int depth)
: superedge_event (kind, eedge, loc, fndecl, depth)
{
  gcc_assert (eedge.m_sedge->m_kind == SUPEREDGE_CFG_EDGE);
}

/* class start_cfg_edge_event : public cfg_edge_event.  */

/* Implementation of diagnostic_event::get_desc vfunc for
   start_cfg_edge_event.

   If -fanalyzer-verbose-edges, then generate low-level descriptions, such
   as
     "taking 'true' edge SN:7 -> SN:8".

   Otherwise, generate strings using the label of the underlying CFG if
   any, such as:
     "following 'true' branch..." or
     "following 'case 3' branch..."
     "following 'default' branch..."

   For conditionals, attempt to supply a description of the condition that
   holds, such as:
     "following 'false' branch (when 'ptr' is non-NULL)..."

   Failing that, return an empty description (which will lead to this event
   being filtered).  */

label_text
start_cfg_edge_event::get_desc (bool can_colorize) const
{
  bool user_facing = !flag_analyzer_verbose_edges;
  char *edge_desc = m_sedge->get_description (user_facing);
  if (user_facing)
    {
      if (edge_desc && strlen (edge_desc) > 0)
	{
	  label_text cond_desc = maybe_describe_condition (can_colorize);
	  label_text result;
	  if (cond_desc.m_buffer)
	    {
	      result = make_label_text (can_colorize,
					"following %qs branch (%s)...",
					edge_desc, cond_desc.m_buffer);
	      cond_desc.maybe_free ();
	    }
	  else
	    {
	      result = make_label_text (can_colorize,
					"following %qs branch...",
					edge_desc);
	    }
	  free (edge_desc);
	  return result;
	}
      else
	{
	  free (edge_desc);
	  return label_text::borrow ("");
	}
    }
  else
    {
      if (strlen (edge_desc) > 0)
	{
	  label_text result
	    = make_label_text (can_colorize,
			       "taking %qs edge SN:%i -> SN:%i",
			       edge_desc,
			       m_sedge->m_src->m_index,
			       m_sedge->m_dest->m_index);
	  free (edge_desc);
	  return result;
	}
      else
	{
	  free (edge_desc);
	  return make_label_text (can_colorize,
				  "taking edge SN:%i -> SN:%i",
				  m_sedge->m_src->m_index,
				  m_sedge->m_dest->m_index);
	}
    }
}

/* Attempt to generate a description of any condition that holds at this edge.

   The intent is to make the user-facing messages more clear, especially for
   cases where there's a single or double-negative, such as
   when describing the false branch of an inverted condition.

   For example, rather than printing just:

      |  if (!ptr)
      |     ~
      |     |
      |     (1) following 'false' branch...

   it's clearer to spell out the condition that holds:

      |  if (!ptr)
      |     ~
      |     |
      |     (1) following 'false' branch (when 'ptr' is non-NULL)...
                                          ^^^^^^^^^^^^^^^^^^^^^^

   In the above example, this function would generate the highlighted
   string: "when 'ptr' is non-NULL".

   If the edge is not a condition, or it's not clear that a description of
   the condition would be helpful to the user, return NULL.  */

label_text
start_cfg_edge_event::maybe_describe_condition (bool can_colorize) const
{
  const cfg_superedge& cfg_sedge = get_cfg_superedge ();

  if (cfg_sedge.true_value_p () || cfg_sedge.false_value_p ())
    {
      const gimple *last_stmt = m_sedge->m_src->get_last_stmt ();
      if (const gcond *cond_stmt = dyn_cast <const gcond *> (last_stmt))
	{
	  enum tree_code op = gimple_cond_code (cond_stmt);
	  tree lhs = gimple_cond_lhs (cond_stmt);
	  tree rhs = gimple_cond_rhs (cond_stmt);
	  if (cfg_sedge.false_value_p ())
	    op = invert_tree_comparison (op, false /* honor_nans */);
	  return maybe_describe_condition (can_colorize,
					   lhs, op, rhs);
	}
    }
  return label_text::borrow (NULL);
}

/* Subroutine of maybe_describe_condition above.

   Attempt to generate a user-facing description of the condition
   LHS OP RHS, but only if it is likely to make it easier for the
   user to understand a condition.  */

label_text
start_cfg_edge_event::maybe_describe_condition (bool can_colorize,
						tree lhs,
						enum tree_code op,
						tree rhs)
{
  /* In theory we could just build a tree via
       fold_build2 (op, boolean_type_node, lhs, rhs)
     and print it with %qE on it, but this leads to warts such as
     parenthesizing vars, such as '(i) <= 9', and uses of '<unknown>'.  */

  /* Special-case: describe testing the result of strcmp, as figuring
     out what the "true" or "false" path is can be confusing to the user.  */
  if (TREE_CODE (lhs) == SSA_NAME
      && zerop (rhs))
    {
      if (gcall *call = dyn_cast <gcall *> (SSA_NAME_DEF_STMT (lhs)))
	if (is_special_named_call_p (call, "strcmp", 2))
	  {
	    if (op == EQ_EXPR)
	      return label_text::borrow ("when the strings are equal");
	    if (op == NE_EXPR)
	      return label_text::borrow ("when the strings are non-equal");
	  }
    }

  /* Only attempt to generate text for sufficiently simple expressions.  */
  if (!should_print_expr_p (lhs))
    return label_text::borrow (NULL);
  if (!should_print_expr_p (rhs))
    return label_text::borrow (NULL);

  /* Special cases for pointer comparisons against NULL.  */
  if (POINTER_TYPE_P (TREE_TYPE (lhs))
      && POINTER_TYPE_P (TREE_TYPE (rhs))
      && zerop (rhs))
    {
      if (op == EQ_EXPR)
	return make_label_text (can_colorize, "when %qE is NULL",
				lhs);
      if (op == NE_EXPR)
	return make_label_text (can_colorize, "when %qE is non-NULL",
				lhs);
    }

  return make_label_text (can_colorize, "when %<%E %s %E%>",
			  lhs, op_symbol_code (op), rhs);
}

/* Subroutine of maybe_describe_condition.

   Return true if EXPR is we will get suitable user-facing output
   from %E on it.  */

bool
start_cfg_edge_event::should_print_expr_p (tree expr)
{
  if (TREE_CODE (expr) == SSA_NAME)
    {
      if (SSA_NAME_VAR (expr))
	return should_print_expr_p (SSA_NAME_VAR (expr));
      else
	return false;
    }

  if (DECL_P (expr))
    return true;

  if (CONSTANT_CLASS_P (expr))
    return true;

  return false;
}

/* class call_event : public superedge_event.  */

/* call_event's ctor.  */

call_event::call_event (const exploded_edge &eedge,
			location_t loc, tree fndecl, int depth)
: superedge_event (EK_CALL_EDGE, eedge, loc, fndecl, depth)
{
  if (eedge.m_sedge)
    gcc_assert (eedge.m_sedge->m_kind == SUPEREDGE_CALL);

   m_src_snode = eedge.m_src->get_supernode ();
   m_dest_snode = eedge.m_dest->get_supernode ();
}

/* Implementation of diagnostic_event::get_desc vfunc for
   call_event.

   If this call event passes critical state for an sm-based warning,
   allow the diagnostic to generate a precise description, such as:

     "passing freed pointer 'ptr' in call to 'foo' from 'bar'"

   Otherwise, generate a description of the form
   "calling 'foo' from 'bar'".  */

label_text
call_event::get_desc (bool can_colorize) const
{
  if (m_critical_state && m_pending_diagnostic)
    {
      gcc_assert (m_var);
      tree var = fixup_tree_for_diagnostic (m_var);
      label_text custom_desc
	= m_pending_diagnostic->describe_call_with_state
	    (evdesc::call_with_state (can_colorize,
				      m_src_snode->m_fun->decl,
				      m_dest_snode->m_fun->decl,
				      var,
				      m_critical_state));
      if (custom_desc.m_buffer)
	return custom_desc;
    }

  return make_label_text (can_colorize,
			  "calling %qE from %qE",
			  m_dest_snode->m_fun->decl,
			  m_src_snode->m_fun->decl);
}

/* Override of checker_event::is_call_p for calls.  */

bool
call_event::is_call_p () const
{
  return true;
}

/* class return_event : public superedge_event.  */

/* return_event's ctor.  */

return_event::return_event (const exploded_edge &eedge,
			    location_t loc, tree fndecl, int depth)
: superedge_event (EK_RETURN_EDGE, eedge, loc, fndecl, depth)
{
  if (eedge.m_sedge)
    gcc_assert (eedge.m_sedge->m_kind == SUPEREDGE_RETURN);

  m_src_snode = eedge.m_src->get_supernode ();
  m_dest_snode = eedge.m_dest->get_supernode ();
}

/* Implementation of diagnostic_event::get_desc vfunc for
   return_event.

   If this return event returns critical state for an sm-based warning,
   allow the diagnostic to generate a precise description, such as:

      "possible of NULL to 'foo' from 'bar'"

   Otherwise, generate a description of the form
   "returning to 'foo' from 'bar'.  */

label_text
return_event::get_desc (bool can_colorize) const
{
  /*  For greatest precision-of-wording, if this is returning the
      state involved in the pending diagnostic, give the pending
      diagnostic a chance to describe this return (in terms of
      itself).  */
  if (m_critical_state && m_pending_diagnostic)
    {
      label_text custom_desc
	= m_pending_diagnostic->describe_return_of_state
	    (evdesc::return_of_state (can_colorize,
				      m_dest_snode->m_fun->decl,
				      m_src_snode->m_fun->decl,
				      m_critical_state));
      if (custom_desc.m_buffer)
	return custom_desc;
    }
  return make_label_text (can_colorize,
			  "returning to %qE from %qE",
			  m_dest_snode->m_fun->decl,
			  m_src_snode->m_fun->decl);
}

/* Override of checker_event::is_return_p for returns.  */

bool
return_event::is_return_p () const
{
  return true;
}

/* class start_consolidated_cfg_edges_event : public checker_event.  */

label_text
start_consolidated_cfg_edges_event::get_desc (bool can_colorize) const
{
  return make_label_text (can_colorize,
			  "following %qs branch...",
			  m_edge_sense ? "true" : "false");
}

/* class setjmp_event : public checker_event.  */

/* Implementation of diagnostic_event::get_desc vfunc for
   setjmp_event.  */

label_text
setjmp_event::get_desc (bool can_colorize) const
{
  return make_label_text (can_colorize,
			  "%qs called here",
			  get_user_facing_name (m_setjmp_call));
}

/* Implementation of checker_event::prepare_for_emission vfunc for setjmp_event.

   Record this setjmp's event ID into the path, so that rewind events can
   use it.  */

void
setjmp_event::prepare_for_emission (checker_path *path,
				    pending_diagnostic *pd,
				    diagnostic_event_id_t emission_id)
{
  checker_event::prepare_for_emission (path, pd, emission_id);
  path->record_setjmp_event (m_enode, emission_id);
}

/* class rewind_event : public checker_event.  */

/* Get the fndecl containing the site of the longjmp call.  */

tree
rewind_event::get_longjmp_caller () const
{
  return m_eedge->m_src->get_function ()->decl;
}

/* Get the fndecl containing the site of the setjmp call.  */

tree
rewind_event::get_setjmp_caller () const
{
  return m_eedge->m_dest->get_function ()->decl;
}

/* rewind_event's ctor.  */

rewind_event::rewind_event (const exploded_edge *eedge,
			    enum event_kind kind,
			    location_t loc, tree fndecl, int depth,
			    const rewind_info_t *rewind_info)
: checker_event (kind, loc, fndecl, depth),
  m_rewind_info (rewind_info),
  m_eedge (eedge)
{
  gcc_assert (m_eedge->m_custom_info == m_rewind_info);
}

/* class rewind_from_longjmp_event : public rewind_event.  */

/* Implementation of diagnostic_event::get_desc vfunc for
   rewind_from_longjmp_event.  */

label_text
rewind_from_longjmp_event::get_desc (bool can_colorize) const
{
  const char *src_name
    = get_user_facing_name (m_rewind_info->get_longjmp_call ());

  if (get_longjmp_caller () == get_setjmp_caller ())
    /* Special-case: purely intraprocedural rewind.  */
    return make_label_text (can_colorize,
			    "rewinding within %qE from %qs...",
			    get_longjmp_caller (),
			    src_name);
  else
    return make_label_text (can_colorize,
			    "rewinding from %qs in %qE...",
			    src_name,
			    get_longjmp_caller ());
}

/* class rewind_to_setjmp_event : public rewind_event.  */

/* Implementation of diagnostic_event::get_desc vfunc for
   rewind_to_setjmp_event.  */

label_text
rewind_to_setjmp_event::get_desc (bool can_colorize) const
{
  const char *dst_name
    = get_user_facing_name (m_rewind_info->get_setjmp_call ());

  /* If we can, identify the ID of the setjmp_event.  */
  if (m_original_setjmp_event_id.known_p ())
    {
      if (get_longjmp_caller () == get_setjmp_caller ())
	/* Special-case: purely intraprocedural rewind.  */
	return make_label_text (can_colorize,
				"...to %qs (saved at %@)",
				dst_name,
				&m_original_setjmp_event_id);
      else
	return make_label_text (can_colorize,
				"...to %qs in %qE (saved at %@)",
				dst_name,
				get_setjmp_caller (),
				&m_original_setjmp_event_id);
    }
  else
    {
      if (get_longjmp_caller () == get_setjmp_caller ())
	/* Special-case: purely intraprocedural rewind.  */
	return make_label_text (can_colorize,
				"...to %qs",
				dst_name,
				get_setjmp_caller ());
      else
	return make_label_text (can_colorize,
				"...to %qs in %qE",
				dst_name,
				get_setjmp_caller ());
    }
}

/* Implementation of checker_event::prepare_for_emission vfunc for
   rewind_to_setjmp_event.

   Attempt to look up the setjmp event ID that recorded the jmp_buf
   for this rewind.  */

void
rewind_to_setjmp_event::prepare_for_emission (checker_path *path,
					      pending_diagnostic *pd,
					      diagnostic_event_id_t emission_id)
{
  checker_event::prepare_for_emission (path, pd, emission_id);
  path->get_setjmp_event (m_rewind_info->get_enode_origin (),
			  &m_original_setjmp_event_id);
}

/* class warning_event : public checker_event.  */

/* Implementation of diagnostic_event::get_desc vfunc for
   warning_event.

   If the pending diagnostic implements describe_final_event, use it,
   generating a precise description e.g.
     "second 'free' here; first 'free' was at (7)"

   Otherwise generate a generic description.  */

label_text
warning_event::get_desc (bool can_colorize) const
{
  if (m_pending_diagnostic)
    {
      tree var = fixup_tree_for_diagnostic (m_var);
      label_text ev_desc
	= m_pending_diagnostic->describe_final_event
	    (evdesc::final_event (can_colorize, var, m_state));
      if (ev_desc.m_buffer)
	{
	  if (m_sm && flag_analyzer_verbose_state_changes)
	    {
	      label_text result;
	      if (var)
		result = make_label_text (can_colorize,
					  "%s (%qE is in state %qs)",
					  ev_desc.m_buffer,
					  var, m_state->get_name ());
	      else
		result = make_label_text (can_colorize,
					  "%s (in global state %qs)",
					  ev_desc.m_buffer,
					  m_state->get_name ());
	      ev_desc.maybe_free ();
	      return result;
	    }
	  else
	    return ev_desc;
	}
    }

  if (m_sm)
    {
      if (m_var)
	return make_label_text (can_colorize,
				"here (%qE is in state %qs)",
				m_var, m_state->get_name ());
      else
	return make_label_text (can_colorize,
				"here (in global state %qs)",
				m_state->get_name ());
    }
  else
    return label_text::borrow ("here");
}

/* Print a single-line representation of this path to PP.  */

void
checker_path::dump (pretty_printer *pp) const
{
  pp_character (pp, '[');

  checker_event *e;
  int i;
  FOR_EACH_VEC_ELT (m_events, i, e)
    {
      if (i > 0)
	pp_string (pp, ", ");
      label_text event_desc (e->get_desc (false));
      pp_printf (pp, "\"%s\"", event_desc.m_buffer);
      event_desc.maybe_free ();
    }
  pp_character (pp, ']');
}

/* Print a multiline form of this path to LOGGER, prefixing it with DESC.  */

void
checker_path::maybe_log (logger *logger, const char *desc) const
{
  if (!logger)
    return;
  logger->start_log_line ();
  logger->log_partial ("%s: ", desc);
  dump (logger->get_printer ());
  logger->end_log_line ();
  for (unsigned i = 0; i < m_events.length (); i++)
    {
      logger->start_log_line ();
      logger->log_partial ("%s[%i]: %s ", desc, i,
			   event_kind_to_string (m_events[i]->m_kind));
      m_events[i]->dump (logger->get_printer ());
      logger->end_log_line ();
    }
}

/* Print a multiline form of this path to STDERR.  */

DEBUG_FUNCTION void
checker_path::debug () const
{
  checker_event *e;
  int i;
  FOR_EACH_VEC_ELT (m_events, i, e)
    {
      label_text event_desc (e->get_desc (false));
      fprintf (stderr,
	       "[%i]: %s \"%s\"\n",
	       i,
	       event_kind_to_string (m_events[i]->m_kind),
	       event_desc.m_buffer);
      event_desc.maybe_free ();
    }
}

/* Add region_creation_event instance to this path for REG,
   describing whether REG is on the stack or heap.  */

void
checker_path::add_region_creation_event (const region *reg,
					 location_t loc,
					 tree fndecl, int depth)
{
  add_event (new region_creation_event (reg, loc, fndecl, depth));
}

/* Add a warning_event to the end of this path.  */

void
checker_path::add_final_event (const state_machine *sm,
			       const exploded_node *enode, const gimple *stmt,
			       tree var, state_machine::state_t state)
{
  checker_event *end_of_path
    = new warning_event (get_stmt_location (stmt, enode->get_function ()),
			 enode->get_function ()->decl,
			 enode->get_stack_depth (),
			 sm, var, state);
  add_event (end_of_path);
}

void
checker_path::fixup_locations (pending_diagnostic *pd)
{
  for (checker_event *e : m_events)
    e->set_location (pd->fixup_location (e->get_location ()));
}

/* Return true if there is a (start_cfg_edge_event, end_cfg_edge_event) pair
   at (IDX, IDX + 1).  */

bool
checker_path::cfg_edge_pair_at_p (unsigned idx) const
{
  if (m_events.length () < idx + 1)
    return false;
  return (m_events[idx]->m_kind == EK_START_CFG_EDGE
	  && m_events[idx + 1]->m_kind == EK_END_CFG_EDGE);
}

} // namespace ana

#endif /* #if ENABLE_ANALYZER */