gcc/analyzer/analysis-plan.cc

   1 /* A class to encapsulate decisions about how the analysis should happen.
   2    Copyright (C) 2019-2022 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 "analyzer/analyzer.h"
  31 #include "diagnostic-core.h"
  32 #include "analyzer/analyzer-logging.h"
  33 #include "analyzer/analysis-plan.h"
  34 #include "ordered-hash-map.h"
  35 #include "options.h"
  36 #include "cgraph.h"
  37 #include "cfg.h"
  38 #include "basic-block.h"
  39 #include "gimple.h"
  40 #include "gimple-iterator.h"
  41 #include "digraph.h"
  42 #include "analyzer/supergraph.h"
  43
  44 #if ENABLE_ANALYZER
  45
  46 /* class analysis_plan.  */
  47
  48 /* analysis_plan's ctor.  */
  49
  50 analysis_plan::analysis_plan (const supergraph &sg, logger *logger)
  51 : log_user (logger), m_sg (sg),
  52   m_cgraph_node_postorder (XCNEWVEC (struct cgraph_node *,
  53                                      symtab->cgraph_count)),
  54   m_index_by_uid (symtab->cgraph_max_uid)
  55 {
  56   LOG_SCOPE (logger);
  57   auto_timevar time (TV_ANALYZER_PLAN);
  58
  59   m_num_cgraph_nodes = ipa_reverse_postorder (m_cgraph_node_postorder);
  60   gcc_assert (m_num_cgraph_nodes == symtab->cgraph_count);
  61   if (get_logger_file ())
  62     ipa_print_order (get_logger_file (),
  63                      "analysis_plan", m_cgraph_node_postorder,
  64                      m_num_cgraph_nodes);
  65
  66   /* Populate m_index_by_uid.  */
  67   for (int i = 0; i < symtab->cgraph_max_uid; i++)
  68     m_index_by_uid.quick_push (-1);
  69   for (int i = 0; i < m_num_cgraph_nodes; i++)
  70     {
  71       gcc_assert (m_cgraph_node_postorder[i]->get_uid ()
  72                   < symtab->cgraph_max_uid);
  73       m_index_by_uid[m_cgraph_node_postorder[i]->get_uid ()] = i;
  74     }
  75 }
  76
  77 /* analysis_plan's dtor.  */
  78
  79 analysis_plan::~analysis_plan ()
  80 {
  81   free (m_cgraph_node_postorder);
  82 }
  83
  84 /* Comparator for use by the exploded_graph's worklist, to order FUN_A
  85    and FUN_B so that functions that are to be summarized are visited
  86    before the summary is needed (based on a sort of the callgraph).  */
  87
  88 int
  89 analysis_plan::cmp_function (function *fun_a, function *fun_b) const
  90 {
  91   cgraph_node *node_a = cgraph_node::get (fun_a->decl);
  92   cgraph_node *node_b = cgraph_node::get (fun_b->decl);
  93
  94   int idx_a = m_index_by_uid[node_a->get_uid ()];
  95   int idx_b = m_index_by_uid[node_b->get_uid ()];
  96
  97   return idx_b - idx_a;
  98 }
  99
 100 /* Return true if the call EDGE should be analyzed using a call summary.
 101    Return false if it should be analyzed using a full call and return.  */
 102
 103 bool
 104 analysis_plan::use_summary_p (const cgraph_edge *edge) const
 105 {
 106   /* Don't use call summaries if -fno-analyzer-call-summaries.  */
 107   if (!flag_analyzer_call_summaries)
 108     return false;
 109
 110   /* Don't use call summaries if there is no callgraph edge */
 111   if (!edge || !edge->callee)
 112     return false;
 113
 114   /* TODO: don't count callsites each time.  */
 115   int num_call_sites = 0;
 116   const cgraph_node *callee = edge->callee;
 117   for (cgraph_edge *edge = callee->callers; edge; edge = edge->next_caller)
 118     ++num_call_sites;
 119
 120   /* Don't use a call summary if there's only one call site.  */
 121   if (num_call_sites <= 1)
 122     return false;
 123
 124   /* Require the callee to be sufficiently complex to be worth
 125      summarizing.  */
 126   const function *fun
 127     = const_cast <cgraph_node *> (callee)->ultimate_alias_target ()->get_fun ();
 128   /* TODO(stage1): can ultimate_alias_target be made const?  */
 129
 130   if ((int)m_sg.get_num_snodes (fun)
 131       < param_analyzer_min_snodes_for_call_summary)
 132     return false;
 133
 134   return true;
 135 }
 136
 137 #endif /* #if ENABLE_ANALYZER */