gcc/value-query.h

   1 /* Support routines for value queries.
   2    Copyright (C) 2020-2022 Free Software Foundation, Inc.
   3    Contributed by Aldy Hernandez <aldyh@redhat.com> and
   4    Andrew Macleod <amacleod@redhat.com>.
   5
   6 This file is part of GCC.
   7
   8 GCC is free software; you can redistribute it and/or modify
   9 it under the terms of the GNU General Public License as published by
  10 the Free Software Foundation; either version 3, or (at your option)
  11 any later version.
  12
  13 GCC is distributed in the hope that it will be useful,
  14 but WITHOUT ANY WARRANTY; without even the implied warranty of
  15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16 GNU General Public License for more details.
  17
  18 You should have received a copy of the GNU General Public License
  19 along with GCC; see the file COPYING3.  If not see
  20 <http://www.gnu.org/licenses/>.  */
  21
  22 #ifndef GCC_QUERY_H
  23 #define GCC_QUERY_H
  24
  25 #include "value-relation.h"
  26
  27 // The value_query class is used by optimization passes that require
  28 // valueizing SSA names in terms of a tree value, but have no neeed
  29 // for ranges.
  30 //
  31 // value_of_expr must be provided.  The default for value_on_edge and
  32 // value_of_stmt is to call value_of_expr.
  33 //
  34 // This implies the valuation is global in nature.  If a pass can make
  35 // use of more specific information, it can override the other queries.
  36 //
  37 // Proper usage of the correct query in passes will enable other
  38 // valuation mechanisms to produce more precise results.
  39
  40 class value_query
  41 {
  42 public:
  43   value_query () { }
  44   // Return the singleton expression for EXPR at a gimple statement,
  45   // or NULL if none found.
  46   virtual tree value_of_expr (tree expr, gimple * = NULL) = 0;
  47   // Return the singleton expression for EXPR at an edge, or NULL if
  48   // none found.
  49   virtual tree value_on_edge (edge, tree expr);
  50   // Return the singleton expression for the LHS of a gimple
  51   // statement, assuming an (optional) initial value of NAME.  Returns
  52   // NULL if none found.
  53   //
  54   // Note that this method calculates the range the LHS would have
  55   // *after* the statement has executed.
  56   virtual tree value_of_stmt (gimple *, tree name = NULL);
  57
  58 private:
  59   DISABLE_COPY_AND_ASSIGN (value_query);
  60 };
  61
  62 // The range_query class is used by optimization passes which are
  63 // range aware.
  64 //
  65 // range_of_expr must be provided.  The default for range_on_edge and
  66 // range_of_stmt is to call range_of_expr.  If a pass can make use of
  67 // more specific information, then it can override the other queries.
  68 //
  69 // The default for the value_* routines is to call the equivalent
  70 // range_* routines, check if the range is a singleton, and return it
  71 // if so.
  72 //
  73 // The get_value_range method is currently provided for compatibility
  74 // with vr-values.  It will be deprecated when possible.
  75
  76 class range_query : public value_query
  77 {
  78 public:
  79   range_query ();
  80   virtual ~range_query ();
  81
  82   virtual tree value_of_expr (tree expr, gimple * = NULL) override;
  83   virtual tree value_on_edge (edge, tree expr) override;
  84   virtual tree value_of_stmt (gimple *, tree name = NULL) override;
  85
  86   // These are the range equivalents of the value_* methods.  Instead
  87   // of returning a singleton, they calculate a range and return it in
  88   // R.  TRUE is returned on success or FALSE if no range was found.
  89   //
  90   // Note that range_of_expr must always return TRUE unless ranges are
  91   // unsupported for EXPR's type (supports_type_p is false).
  92   virtual bool range_of_expr (vrange &r, tree expr, gimple * = NULL) = 0;
  93   virtual bool range_on_edge (vrange &r, edge, tree expr);
  94   virtual bool range_of_stmt (vrange &r, gimple *, tree name = NULL);
  95
  96   // When the IL in a stmt is changed, call this for better results.
  97   virtual void update_stmt (gimple *) { }
  98
  99   // Query if there is any relation between SSA1 and SSA2.
 100   relation_kind query_relation (gimple *s, tree ssa1, tree ssa2,
 101                                 bool get_range = true);
 102   relation_kind query_relation (edge e, tree ssa1, tree ssa2,
 103                                 bool get_range = true);
 104   // If present, Access relation oracle for more advanced uses.
 105   inline relation_oracle *oracle () const  { return m_oracle; }
 106
 107   // DEPRECATED: This method is used from vr-values.  The plan is to
 108   // rewrite all uses of it to the above API.
 109   virtual const value_range *get_value_range (const_tree, gimple * = NULL);
 110   virtual void dump (FILE *);
 111
 112 protected:
 113   bool get_tree_range (vrange &v, tree expr, gimple *stmt);
 114   bool get_arith_expr_range (vrange &r, tree expr, gimple *stmt);
 115   relation_oracle *m_oracle;
 116
 117 private:
 118   class equiv_allocator *equiv_alloc;
 119 };
 120
 121 // Global ranges for SSA names using SSA_NAME_RANGE_INFO.
 122
 123 class global_range_query : public range_query
 124 {
 125 public:
 126   bool range_of_expr (vrange &r, tree expr, gimple * = NULL) override;
 127 };
 128
 129 extern global_range_query global_ranges;
 130
 131 inline range_query *
 132 get_global_range_query ()
 133 {
 134   return &global_ranges;
 135 }
 136
 137 /* Returns the currently active range access class.  When there is no active
 138    range class, global ranges are used.  Never returns null.  */
 139
 140 ATTRIBUTE_RETURNS_NONNULL inline range_query *
 141 get_range_query (const struct function *fun)
 142 {
 143   return fun->x_range_query ? fun->x_range_query : &global_ranges;
 144 }
 145
 146 extern void gimple_range_global (vrange &v, tree name);
 147
 148 #endif // GCC_QUERY_H