1 /* A class to encapsulate decisions about how the analysis should happen.
2 Copyright (C) 2019-2021 Free Software Foundation, Inc.
3 Contributed by David Malcolm <dmalcolm@redhat.com>.
4
5 This file is part of GCC.
6
7 GCC is free software; you can redistribute it and/or modify it
8 under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 3, or (at your option)
10 any later version.
11
12 GCC is distributed in the hope that it will be useful, but
13 WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 General Public License 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 #include "config.h"
22 #include "system.h"
23 #include "coretypes.h"
24 #include "tree.h"
25 #include "options.h"
26 #include "cgraph.h"
27 #include "timevar.h"
28 #include "ipa-utils.h"
29 #include "function.h"
30 #include "json.h"
31 #include "analyzer/analyzer.h"
32 #include "diagnostic-core.h"
33 #include "analyzer/analyzer-logging.h"
34 #include "analyzer/analysis-plan.h"
35 #include "ordered-hash-map.h"
36 #include "options.h"
37 #include "cgraph.h"
38 #include "function.h"
39 #include "cfg.h"
40 #include "basic-block.h"
41 #include "gimple.h"
42 #include "gimple-iterator.h"
43 #include "digraph.h"
44 #include "analyzer/supergraph.h"
45
46 #if ENABLE_ANALYZER
47
48 /* class analysis_plan. */
49
50 /* analysis_plan's ctor. */
51
analysis_plan(const supergraph & sg,logger * logger)52 analysis_plan::analysis_plan (const supergraph &sg, logger *logger)
53 : log_user (logger), m_sg (sg),
54 m_cgraph_node_postorder (XCNEWVEC (struct cgraph_node *,
55 symtab->cgraph_count)),
56 m_index_by_uid (symtab->cgraph_max_uid)
57 {
58 LOG_SCOPE (logger);
59 auto_timevar time (TV_ANALYZER_PLAN);
60
61 m_num_cgraph_nodes = ipa_reverse_postorder (m_cgraph_node_postorder);
62 gcc_assert (m_num_cgraph_nodes == symtab->cgraph_count);
63 if (get_logger_file ())
64 ipa_print_order (get_logger_file (),
65 "analysis_plan", m_cgraph_node_postorder,
66 m_num_cgraph_nodes);
67
68 /* Populate m_index_by_uid. */
69 for (int i = 0; i < symtab->cgraph_max_uid; i++)
70 m_index_by_uid.quick_push (-1);
71 for (int i = 0; i < m_num_cgraph_nodes; i++)
72 {
73 gcc_assert (m_cgraph_node_postorder[i]->get_uid ()
74 < symtab->cgraph_max_uid);
75 m_index_by_uid[m_cgraph_node_postorder[i]->get_uid ()] = i;
76 }
77 }
78
79 /* analysis_plan's dtor. */
80
~analysis_plan()81 analysis_plan::~analysis_plan ()
82 {
83 free (m_cgraph_node_postorder);
84 }
85
86 /* Comparator for use by the exploded_graph's worklist, to order FUN_A
87 and FUN_B so that functions that are to be summarized are visited
88 before the summary is needed (based on a sort of the callgraph). */
89
90 int
cmp_function(function * fun_a,function * fun_b) const91 analysis_plan::cmp_function (function *fun_a, function *fun_b) const
92 {
93 cgraph_node *node_a = cgraph_node::get (fun_a->decl);
94 cgraph_node *node_b = cgraph_node::get (fun_b->decl);
95
96 int idx_a = m_index_by_uid[node_a->get_uid ()];
97 int idx_b = m_index_by_uid[node_b->get_uid ()];
98
99 return idx_b - idx_a;
100 }
101
102 /* Return true if the call EDGE should be analyzed using a call summary.
103 Return false if it should be analyzed using a full call and return. */
104
105 bool
use_summary_p(const cgraph_edge * edge) const106 analysis_plan::use_summary_p (const cgraph_edge *edge) const
107 {
108 /* Don't use call summaries if -fno-analyzer-call-summaries. */
109 if (!flag_analyzer_call_summaries)
110 return false;
111
112 /* Don't use call summaries if there is no callgraph edge */
113 if (!edge || !edge->callee)
114 return false;
115
116 /* TODO: don't count callsites each time. */
117 int num_call_sites = 0;
118 const cgraph_node *callee = edge->callee;
119 for (cgraph_edge *edge = callee->callers; edge; edge = edge->next_caller)
120 ++num_call_sites;
121
122 /* Don't use a call summary if there's only one call site. */
123 if (num_call_sites <= 1)
124 return false;
125
126 /* Require the callee to be sufficiently complex to be worth
127 summarizing. */
128 const function *fun
129 = const_cast <cgraph_node *> (callee)->ultimate_alias_target ()->get_fun ();
130 /* TODO(stage1): can ultimate_alias_target be made const? */
131
132 if ((int)m_sg.get_num_snodes (fun)
133 < param_analyzer_min_snodes_for_call_summary)
134 return false;
135
136 return true;
137 }
138
139 #endif /* #if ENABLE_ANALYZER */
140