gcc/analyzer/kf-lang-cp.cc

   1 /* Handling for the known behavior of various functions specific to C++.
   2    Copyright (C) 2020-2023 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 #define INCLUDE_MEMORY
  23 #include "system.h"
  24 #include "coretypes.h"
  25 #include "tree.h"
  26 #include "function.h"
  27 #include "basic-block.h"
  28 #include "gimple.h"
  29 #include "analyzer/analyzer.h"
  30 #include "analyzer/analyzer-logging.h"
  31 #include "diagnostic.h"
  32 #include "analyzer/region-model.h"
  33 #include "analyzer/call-details.h"
  34 #include "make-unique.h"
  35
  36 #if ENABLE_ANALYZER
  37
  38 namespace ana {
  39
  40 /* Implementations of specific functions.  */
  41
  42 /* Handler for "operator new" and "operator new []".  */
  43
  44 class kf_operator_new : public known_function
  45 {
  46 public:
  47   bool matches_call_types_p (const call_details &cd) const final override
  48   {
  49     return cd.num_args () == 1;
  50   }
  51
  52   void impl_call_pre (const call_details &cd) const final override
  53   {
  54     region_model *model = cd.get_model ();
  55     region_model_manager *mgr = cd.get_manager ();
  56     const svalue *size_sval = cd.get_arg_svalue (0);
  57     const region *new_reg
  58       = model->get_or_create_region_for_heap_alloc (size_sval, cd.get_ctxt ());
  59     if (cd.get_lhs_type ())
  60       {
  61         const svalue *ptr_sval
  62           = mgr->get_ptr_svalue (cd.get_lhs_type (), new_reg);
  63         cd.maybe_set_lhs (ptr_sval);
  64       }
  65   }
  66 };
  67
  68 /* Handler for "operator delete", both the sized and unsized variants
  69    (2 arguments and 1 argument respectively), and for "operator delete []"  */
  70
  71 class kf_operator_delete : public known_function
  72 {
  73 public:
  74   kf_operator_delete (unsigned num_args) : m_num_args (num_args) {}
  75
  76   bool matches_call_types_p (const call_details &cd) const final override
  77   {
  78     return cd.num_args () == m_num_args;
  79   }
  80
  81   void impl_call_post (const call_details &cd) const final override
  82   {
  83     region_model *model = cd.get_model ();
  84     const svalue *ptr_sval = cd.get_arg_svalue (0);
  85     if (const region *freed_reg = ptr_sval->maybe_get_region ())
  86       {
  87         /* If the ptr points to an underlying heap region, delete it,
  88            poisoning pointers.  */
  89         model->unbind_region_and_descendents (freed_reg, POISON_KIND_FREED);
  90       }
  91   }
  92
  93 private:
  94   unsigned m_num_args;
  95 };
  96
  97 /* Populate KFM with instances of known functions relating to C++.  */
  98
  99 void
 100 register_known_functions_lang_cp (known_function_manager &kfm)
 101 {
 102   kfm.add ("operator new", make_unique<kf_operator_new> ());
 103   kfm.add ("operator new []", make_unique<kf_operator_new> ());
 104   kfm.add ("operator delete", make_unique<kf_operator_delete> (1));
 105   kfm.add ("operator delete", make_unique<kf_operator_delete> (2));
 106   kfm.add ("operator delete []", make_unique<kf_operator_delete> (1));
 107 }
 108
 109 } // namespace ana
 110
 111 #endif /* #if ENABLE_ANALYZER */