1 /* Call stacks at program points.
2 Copyright (C) 2019-2020 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 "pretty-print.h"
25 #include "tree.h"
26 #include "options.h"
27 #include "analyzer/call-string.h"
28 #include "ordered-hash-map.h"
29 #include "options.h"
30 #include "cgraph.h"
31 #include "function.h"
32 #include "cfg.h"
33 #include "basic-block.h"
34 #include "gimple.h"
35 #include "gimple-iterator.h"
36 #include "digraph.h"
37 #include "analyzer/supergraph.h"
38
39 #if ENABLE_ANALYZER
40
41 /* class call_string. */
42
43 /* call_string's copy ctor. */
44
call_string(const call_string & other)45 call_string::call_string (const call_string &other)
46 : m_return_edges (other.m_return_edges.length ())
47 {
48 const return_superedge *e;
49 int i;
50 FOR_EACH_VEC_ELT (other.m_return_edges, i, e)
51 m_return_edges.quick_push (e);
52 }
53
54 /* call_string's assignment operator. */
55
56 call_string&
operator =(const call_string & other)57 call_string::operator= (const call_string &other)
58 {
59 // would be much simpler if we could rely on vec<> assignment op
60 m_return_edges.truncate (0);
61 m_return_edges.reserve (other.m_return_edges.length (), true);
62 const return_superedge *e;
63 int i;
64 FOR_EACH_VEC_ELT (other.m_return_edges, i, e)
65 m_return_edges.quick_push (e);
66 return *this;
67 }
68
69 /* call_string's equality operator. */
70
71 bool
operator ==(const call_string & other) const72 call_string::operator== (const call_string &other) const
73 {
74 if (m_return_edges.length () != other.m_return_edges.length ())
75 return false;
76 const return_superedge *e;
77 int i;
78 FOR_EACH_VEC_ELT (m_return_edges, i, e)
79 if (e != other.m_return_edges[i])
80 return false;
81 return true;
82 }
83
84 /* Print this to PP. */
85
86 void
print(pretty_printer * pp) const87 call_string::print (pretty_printer *pp) const
88 {
89 pp_string (pp, "[");
90
91 const return_superedge *e;
92 int i;
93 FOR_EACH_VEC_ELT (m_return_edges, i, e)
94 {
95 if (i > 0)
96 pp_string (pp, ", ");
97 pp_printf (pp, "(SN: %i -> SN: %i in %s)",
98 e->m_src->m_index, e->m_dest->m_index,
99 function_name (e->m_dest->m_fun));
100 }
101
102 pp_string (pp, "]");
103 }
104
105 /* Generate a hash value for this call_string. */
106
107 hashval_t
hash() const108 call_string::hash () const
109 {
110 inchash::hash hstate;
111 int i;
112 const return_superedge *e;
113 FOR_EACH_VEC_ELT (m_return_edges, i, e)
114 hstate.add_ptr (e);
115 return hstate.end ();
116 }
117
118 /* Push the return superedge for CALL_SEDGE onto the end of this
119 call_string. */
120
121 void
push_call(const supergraph & sg,const call_superedge * call_sedge)122 call_string::push_call (const supergraph &sg,
123 const call_superedge *call_sedge)
124 {
125 gcc_assert (call_sedge);
126 const return_superedge *return_sedge = call_sedge->get_edge_for_return (sg);
127 gcc_assert (return_sedge);
128 m_return_edges.safe_push (return_sedge);
129 }
130
131 /* Count the number of times the top-most call site appears in the
132 stack. */
133
134 int
calc_recursion_depth() const135 call_string::calc_recursion_depth () const
136 {
137 if (m_return_edges.is_empty ())
138 return 0;
139 const return_superedge *top_return_sedge
140 = m_return_edges[m_return_edges.length () - 1];
141
142 int result = 0;
143 const return_superedge *e;
144 int i;
145 FOR_EACH_VEC_ELT (m_return_edges, i, e)
146 if (e == top_return_sedge)
147 ++result;
148 return result;
149 }
150
151 /* Comparator for call strings.
152 This implements a version of lexicographical order.
153 Return negative if A is before B.
154 Return positive if B is after A.
155 Return 0 if they are equal. */
156
157 int
cmp(const call_string & a,const call_string & b)158 call_string::cmp (const call_string &a,
159 const call_string &b)
160 {
161 unsigned len_a = a.length ();
162 unsigned len_b = b.length ();
163
164 unsigned i = 0;
165 while (1)
166 {
167 /* Consider index i; the strings have been equal up to it. */
168
169 /* Have both strings run out? */
170 if (i >= len_a && i >= len_b)
171 return 0;
172
173 /* Otherwise, has just one of the strings run out? */
174 if (i >= len_a)
175 return 1;
176 if (i >= len_b)
177 return -1;
178
179 /* Otherwise, compare the edges. */
180 const return_superedge *edge_a = a[i];
181 const return_superedge *edge_b = b[i];
182 int src_cmp = edge_a->m_src->m_index - edge_b->m_src->m_index;
183 if (src_cmp)
184 return src_cmp;
185 int dest_cmp = edge_a->m_dest->m_index - edge_b->m_dest->m_index;
186 if (dest_cmp)
187 return dest_cmp;
188 i++;
189 // TODO: test coverage for this
190 }
191 }
192
193 /* Assert that this object is sane. */
194
195 void
validate() const196 call_string::validate () const
197 {
198 /* Skip this in a release build. */
199 #if !CHECKING_P
200 return;
201 #endif
202
203 /* Each entry's "caller" should be the "callee" of the previous entry. */
204 const return_superedge *e;
205 int i;
206 FOR_EACH_VEC_ELT (m_return_edges, i, e)
207 if (i > 0)
208 gcc_assert (e->get_caller_function ()
209 == m_return_edges[i - 1]->get_callee_function ());
210 }
211
212 #endif /* #if ENABLE_ANALYZER */
213