| 1 | /* Digraph reachability. |
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| 2 | Copyright (C) 2020-2024 Free Software Foundation, Inc. |
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| 3 | Contributed by David Malcolm <dmalcolm@redhat.com>. |
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| 4 | |
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| 5 | This file is part of GCC. |
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| 6 | |
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| 7 | GCC is free software; you can redistribute it and/or modify it |
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| 8 | under the terms of the GNU General Public License as published by |
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| 9 | the Free Software Foundation; either version 3, or (at your option) |
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| 10 | any later version. |
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| 11 | |
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| 12 | GCC is distributed in the hope that it will be useful, but |
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| 13 | WITHOUT ANY WARRANTY; without even the implied warranty of |
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| 14 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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| 15 | General Public License for more details. |
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| 16 | |
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| 17 | You should have received a copy of the GNU General Public License |
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| 18 | along with GCC; see the file COPYING3. If not see |
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| 19 | <http://www.gnu.org/licenses/>. */ |
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| 20 | |
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| 21 | #ifndef GCC_ANALYZER_REACHABILITY_H |
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| 22 | #define GCC_ANALYZER_REACHABILITY_H |
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| 23 | |
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| 24 | namespace ana { |
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| 25 | |
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| 26 | /* The set of nodes from which a target node in a digraph can be reached. */ |
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| 27 | // TODO(stage1): move to gcc |
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| 28 | |
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| 29 | template <typename GraphTraits> |
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| 30 | class reachability |
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| 31 | { |
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| 32 | public: |
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| 33 | typedef typename GraphTraits::graph_t graph_t; |
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| 34 | typedef typename GraphTraits::node_t node_t; |
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| 35 | typedef typename GraphTraits::edge_t edge_t; |
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| 36 | |
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| 37 | reachability (const graph_t &graph, |
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| 38 | const node_t *target_node) |
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| 39 | : m_indices (graph.m_nodes.length ()) |
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| 40 | { |
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| 41 | bitmap_clear (m_indices); |
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| 42 | auto_vec<const node_t *> worklist; |
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| 43 | worklist.safe_push (target_node); |
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| 44 | bitmap_set_bit (m_indices, target_node->m_index); |
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| 45 | |
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| 46 | while (worklist.length () > 0) |
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| 47 | { |
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| 48 | const node_t *next = worklist.pop (); |
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| 49 | unsigned i; |
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| 50 | edge_t *pred; |
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| 51 | FOR_EACH_VEC_ELT (next->m_preds, i, pred) |
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| 52 | { |
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| 53 | if (!reachable_from_p (src_node: pred->m_src)) |
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| 54 | { |
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| 55 | worklist.safe_push (pred->m_src); |
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| 56 | bitmap_set_bit (m_indices, pred->m_src->m_index); |
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| 57 | } |
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| 58 | } |
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| 59 | } |
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| 60 | } |
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| 61 | |
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| 62 | bool reachable_from_p (const node_t *src_node) const |
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| 63 | { |
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| 64 | return bitmap_bit_p (m_indices, src_node->m_index); |
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| 65 | } |
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| 66 | |
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| 67 | private: |
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| 68 | /* The nodes that can reach the target. */ |
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| 69 | auto_sbitmap m_indices; |
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| 70 | }; |
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| 71 | |
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| 72 | //TODO: selftests for reachability |
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| 73 | |
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| 74 | } // namespace ana |
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| 75 | |
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| 76 | #endif /* GCC_ANALYZER_REACHABILITY_H */ |
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| 77 | |
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