path: root/gcc/gimple-range.h

/* Header file for the GIMPLE range interface.
   Copyright (C) 2019-2021 Free Software Foundation, Inc.
   Contributed by Andrew MacLeod <amacleod@redhat.com>
   and Aldy Hernandez <aldyh@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/>.  */

#ifndef GCC_GIMPLE_RANGE_STMT_H
#define GCC_GIMPLE_RANGE_STMT_H


#include "range.h"
#include "range-op.h"
#include "gimple-range-edge.h"
#include "gimple-range-gori.h"
#include "gimple-range-cache.h"
#include "value-query.h"

// This file is the main include point for gimple ranges.
// There are two fold_range routines of interest:
//   bool fold_range (irange &r, gimple *s, range_query *q)
//   bool fold_range (irange &r, gimple *s, edge on_edge, range_query *q)
// These routines will fold stmt S into the result irange R.
// Any ssa_names on the stmt will be calculated using the range_query
// parameter via a call to range_of_expr.
// If no range_query is provided, current global range info will be used.
// The second variation specifies an edge, and stmt S is recalculated as if
// it appeared on that edge.


// This is the basic range generator interface.
//
// This base class provides all the API entry points, but only provides
// functionality at the statement level.  Ie, it can calculate ranges on
// statements, but does no additonal lookup.
//
// All the range_of_* methods will return a range if the types is
// supported by the range engine.  It may be the full range for the
// type, AKA varying_p or it may be a refined range.  If the range
// type is not supported, then false is returned.  Non-statement
// related methods return whatever the current global value is.


class gimple_ranger : public range_query
{
public:
  gimple_ranger () : m_cache (*this) { }
  virtual bool range_of_stmt (irange &r, gimple *, tree name = NULL) OVERRIDE;
  virtual bool range_of_expr (irange &r, tree name, gimple * = NULL) OVERRIDE;
  virtual bool range_on_edge (irange &r, edge e, tree name) OVERRIDE;
  virtual void range_on_entry (irange &r, basic_block bb, tree name);
  virtual void range_on_exit (irange &r, basic_block bb, tree name);
  void export_global_ranges ();
  void dump (FILE *f);
  void dump_bb (FILE *f, basic_block bb);
protected:
  bool fold_range_internal (irange &r, gimple *s, tree name);
  ranger_cache m_cache;
};

// Source of an operand for fold_using_range.
// It can specify a stmt or and edge, or thru an internal API which uses
// the ranger cache.
// Its primary function is to retreive an operand from the source via a
// call thru the range_query object.

class fur_source
{
  friend class fold_using_range;
public:
  inline fur_source (range_query *q, edge e);
  inline fur_source (range_query *q, gimple *s);
  inline fur_source (range_query *q, gori_compute *g, edge e, gimple *s);
  bool get_operand (irange &r, tree expr);
protected:
  gori_compute *m_gori;
  range_query *m_query;
  edge m_edge;
  gimple *m_stmt;
};


// This class uses ranges to fold a gimple statement producinf a range for
// the LHS.  The source of all operands is supplied via the fur_source class
// which provides a range_query as well as a source location and any other
// required information.

class fold_using_range
{
public:
  bool fold_stmt (irange &r, gimple *s, class fur_source &src,
		  tree name = NULL_TREE);
protected:
  bool range_of_range_op (irange &r, gimple *s, fur_source &src);
  bool range_of_call (irange &r, gcall *call, fur_source &src);
  bool range_of_cond_expr (irange &r, gassign* cond, fur_source &src);
  bool range_of_address (irange &r, gimple *s, fur_source &src);
  bool range_of_builtin_call (irange &r, gcall *call, fur_source &src);
  void range_of_builtin_ubsan_call (irange &r, gcall *call, tree_code code,
				    fur_source &src);
  bool range_of_phi (irange &r, gphi *phi, fur_source &src);
  void range_of_ssa_name_with_loop_info (irange &, tree, class loop *, gphi *,
					 fur_source &src);
};


// Create a source for a query on an edge.

inline
fur_source::fur_source (range_query *q, edge e)
{
  m_query = q;
  m_gori = NULL;
  m_edge = e;
  m_stmt = NULL;
}

// Create a source for a query at a statement.

inline
fur_source::fur_source (range_query *q, gimple *s)
{
  m_query = q;
  m_gori = NULL;
  m_edge = NULL;
  m_stmt = s;
}

// Create a source for Ranger.  THis can recalculate from a different location
// and can also set the dependency information as appropriate when invoked.

inline
fur_source::fur_source (range_query *q, gori_compute *g, edge e, gimple *s)
{
  m_query = q;
  m_gori = g;
  m_edge = e;
  m_stmt = s;
}

// Fold stmt S into range R using range query Q.

inline bool
fold_range (irange &r, gimple *s, range_query *q = NULL)
{
  fold_using_range f;
  fur_source src (q, s);
  return f.fold_stmt (r, s, src);
}

// Recalculate stmt S into R using range query Q as if it were on edge ON_EDGE.

inline bool
fold_range (irange &r, gimple *s, edge on_edge, range_query *q = NULL)
{
  fold_using_range f;
  fur_source src (q, on_edge);
  return f.fold_stmt (r, s, src);
}

// Calculate a basic range for a tree node expression.
extern bool get_tree_range (irange &r, tree expr);

// These routines provide a GIMPLE interface to the range-ops code.
extern tree gimple_range_operand1 (const gimple *s);
extern tree gimple_range_operand2 (const gimple *s);
extern bool gimple_range_calc_op1 (irange &r, const gimple *s,
				   const irange &lhs_range);
extern bool gimple_range_calc_op1 (irange &r, const gimple *s,
				   const irange &lhs_range,
				   const irange &op2_range);
extern bool gimple_range_calc_op2 (irange &r, const gimple *s,
				   const irange &lhs_range,
				   const irange &op1_range);


// Return the range_operator pointer for this statement.  This routine
// can also be used to gate whether a routine is range-ops enabled.

static inline range_operator *
gimple_range_handler (const gimple *s)
{
  if (const gassign *ass = dyn_cast<const gassign *> (s))
    return range_op_handler (gimple_assign_rhs_code (ass),
			     TREE_TYPE (gimple_assign_lhs (ass)));
  if (const gcond *cond = dyn_cast<const gcond *> (s))
    return range_op_handler (gimple_cond_code (cond),
			     TREE_TYPE (gimple_cond_lhs (cond)));
  return NULL;
}

// Return EXP if it is an SSA_NAME with a type supported by gimple ranges.

static inline tree
gimple_range_ssa_p (tree exp)
{
  if (exp && TREE_CODE (exp) == SSA_NAME &&
      !SSA_NAME_IS_VIRTUAL_OPERAND (exp) &&
      irange::supports_type_p (TREE_TYPE (exp)))
    return exp;
  return NULL_TREE;
}

// Return true if TYPE1 and TYPE2 are compatible range types.

static inline bool
range_compatible_p (tree type1, tree type2)
{
  // types_compatible_p requires conversion in both directions to be useless.
  // GIMPLE only requires a cast one way in order to be compatible.
  // Ranges really only need the sign and precision to be the same.
  return (TYPE_PRECISION (type1) == TYPE_PRECISION (type2)
	  && TYPE_SIGN (type1) == TYPE_SIGN (type2));
}

// Return the legacy GCC global range for NAME if it has one, otherwise
// return VARYING.

static inline value_range
gimple_range_global (tree name)
{
  gcc_checking_assert (gimple_range_ssa_p (name));
  tree type = TREE_TYPE (name);

  if (SSA_NAME_IS_DEFAULT_DEF (name))
    {
      tree sym = SSA_NAME_VAR (name);
      // Adapted from vr_values::get_lattice_entry().
      // Use a range from an SSA_NAME's available range.
      if (TREE_CODE (sym) == PARM_DECL)
	{
	  // Try to use the "nonnull" attribute to create ~[0, 0]
	  // anti-ranges for pointers.  Note that this is only valid with
	  // default definitions of PARM_DECLs.
	  if (POINTER_TYPE_P (type)
	      && (nonnull_arg_p (sym) || get_ptr_nonnull (name)))
	    {
	      value_range r;
	      r.set_nonzero (type);
	      return r;
	    }
	  else if (INTEGRAL_TYPE_P (type))
	    {
	      value_range r;
	      get_range_info (name, r);
	      if (r.undefined_p ())
		r.set_varying (type);
	      return r;
	    }
	}
      // If this is a local automatic with no definition, use undefined.
      else if (TREE_CODE (sym) != RESULT_DECL)
	return value_range ();
   }
  // Otherwise return range for the type.
  return value_range (type);
}


// This class overloads the ranger routines to provide tracing facilties
// Entry and exit values to each of the APIs is placed in the dumpfile.

class trace_ranger : public gimple_ranger
{
public:
  trace_ranger ();
  virtual bool range_of_stmt (irange &r, gimple *s, tree name = NULL_TREE);
  virtual bool range_of_expr (irange &r, tree name, gimple *s = NULL);
  virtual bool range_on_edge (irange &r, edge e, tree name);
  virtual void range_on_entry (irange &r, basic_block bb, tree name);
  virtual void range_on_exit (irange &r, basic_block bb, tree name);
private:
  static const unsigned bump = 2;
  unsigned indent;
  unsigned trace_count;		// Current trace index count.

  bool dumping (unsigned counter, bool trailing = false);
  bool trailer (unsigned counter, const char *caller, bool result, tree name,
		const irange &r);
};

// Flag to enable debugging the various internal Caches.
#define DEBUG_RANGE_CACHE (dump_file && (param_evrp_mode & EVRP_MODE_DEBUG))

#endif // GCC_GIMPLE_RANGE_STMT_H