1 /* Header file for jump threading path solver.
2    Copyright (C) 2021-2022 Free Software Foundation, Inc.
3    Contributed by Aldy Hernandez <aldyh@redhat.com>.
4 
5 This file is part of GCC.
6 
7 GCC is free software; you can redistribute it and/or modify it under
8 the terms of the GNU General Public License as published by the Free
9 Software Foundation; either version 3, or (at your option) any later
10 version.
11 
12 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
13 WARRANTY; without even the implied warranty of MERCHANTABILITY or
14 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
15  for more details.
16 
17 You should have received a copy of the GNU General Public License
18 along with GCC; see the file COPYING3.  If not see
19 <http://www.gnu.org/licenses/>.  */
20 
21 #ifndef GCC_TREE_SSA_THREADSOLVER_H
22 #define GCC_TREE_SSA_THREADSOLVER_H
23 
24 // This class is a basic block path solver.  Given a set of BBs
25 // indicating a path through the CFG, range_of_expr and range_of_stmt
26 // will calculate the range of an SSA or STMT as if the BBs in the
27 // path would have been executed in order.
28 //
29 // Note that the blocks are in reverse order, thus the exit block is
30 // path[0].
31 
32 class path_range_query : public range_query
33 {
34 public:
35   path_range_query (bool resolve = true, class gimple_ranger *ranger = NULL);
36   virtual ~path_range_query ();
37   void compute_ranges (const vec<basic_block> &,
38 		       const bitmap_head *imports = NULL);
39   void compute_ranges (edge e);
40   void compute_imports (bitmap imports, basic_block exit);
41   bool range_of_expr (irange &r, tree name, gimple * = NULL) override;
42   bool range_of_stmt (irange &r, gimple *, tree name = NULL) override;
43   bool unreachable_path_p ();
44   void dump (FILE *) override;
45   void debug ();
46 
47 private:
48   bool internal_range_of_expr (irange &r, tree name, gimple *);
49   bool defined_outside_path (tree name);
50   void range_on_path_entry (irange &r, tree name);
get_path_oracle()51   path_oracle *get_path_oracle () { return (path_oracle *)m_oracle; }
52 
53   // Cache manipulation.
54   void set_cache (const irange &r, tree name);
55   bool get_cache (irange &r, tree name);
56   void clear_cache (tree name);
57 
58   // Methods to compute ranges for the given path.
59   bool range_defined_in_block (irange &, tree name, basic_block bb);
60   void compute_ranges_in_block (basic_block bb);
61   void compute_ranges_in_phis (basic_block bb);
62   void adjust_for_non_null_uses (basic_block bb);
63   void ssa_range_in_phi (irange &r, gphi *phi);
64   void compute_outgoing_relations (basic_block bb, basic_block next);
65   void compute_phi_relations (basic_block bb, basic_block prev);
66   void maybe_register_phi_relation (gphi *, edge e);
67   bool add_to_imports (tree name, bitmap imports);
68   bool import_p (tree name);
69   bool ssa_defined_in_bb (tree name, basic_block bb);
70   bool relations_may_be_invalidated (edge);
71 
72   // Path navigation.
73   void set_path (const vec<basic_block> &);
entry_bb()74   basic_block entry_bb () { return m_path[m_path.length () - 1]; }
exit_bb()75   basic_block exit_bb ()  { return m_path[0]; }
curr_bb()76   basic_block curr_bb ()  { return m_path[m_pos]; }
prev_bb()77   basic_block prev_bb ()  { return m_path[m_pos + 1]; }
next_bb()78   basic_block next_bb ()  { return m_path[m_pos - 1]; }
at_entry()79   bool at_entry ()	  { return m_pos == m_path.length () - 1; }
at_exit()80   bool at_exit ()	  { return m_pos == 0; }
move_next()81   void move_next ()	  { --m_pos; }
82 
83   // Range cache for SSA names.
84   ssa_global_cache *m_cache;
85 
86   // Set for each SSA that has an active entry in the cache.
87   bitmap m_has_cache_entry;
88 
89   // Path being analyzed.
90   auto_vec<basic_block> m_path;
91 
92   auto_bitmap m_imports;
93   gimple_ranger *m_ranger;
94   non_null_ref m_non_null;
95 
96   // Current path position.
97   unsigned m_pos;
98 
99   // Use ranger to resolve anything not known on entry.
100   bool m_resolve;
101 
102   // Set if there were any undefined expressions while pre-calculating path.
103   bool m_undefined_path;
104 
105   // True if m_ranger was allocated in this class and must be freed at
106   // destruction.
107   bool m_alloced_ranger;
108 };
109 
110 #endif // GCC_TREE_SSA_THREADSOLVER_H
111