cprover
label_function_pointer_call_sites.cpp
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1 /*******************************************************************\
2 Module: Label function pointer call sites
3 Author: Diffblue Ltd.
4 \*******************************************************************/
5 
8 
10 
11 #include <util/fresh_symbol.h>
12 #include <util/pointer_expr.h>
13 
15 {
16  for(auto &goto_function : goto_model.goto_functions.function_map)
17  {
18  std::size_t function_pointer_call_counter = 0;
19 
21  goto_function.second,
22  [](const goto_programt::targett it) {
23  return it->is_function_call() && can_cast_expr<dereference_exprt>(
24  it->get_function_call().function());
25  },
26  [&](goto_programt::targett &it) {
27  auto const &function_call = it->get_function_call();
28  auto const &function_pointer_dereference =
29  to_dereference_expr(function_call.function());
30  auto const &source_location = function_call.source_location();
31  auto const &goto_function_symbol_mode =
32  goto_model.symbol_table.lookup_ref(goto_function.first).mode;
33 
34  auto const call_site_symbol_name =
35  irep_idt{id2string(goto_function.first) + ".function_pointer_call." +
36  std::to_string(++function_pointer_call_counter)};
37 
38  // insert new function pointer variable into the symbol table
39  goto_model.symbol_table.insert([&] {
40  symbolt function_call_site_symbol{};
41  function_call_site_symbol.name = function_call_site_symbol.base_name =
42  function_call_site_symbol.pretty_name = call_site_symbol_name;
43  function_call_site_symbol.type =
44  function_pointer_dereference.pointer().type();
45  function_call_site_symbol.location = function_call.source_location();
46  function_call_site_symbol.is_lvalue = true;
47  function_call_site_symbol.mode = goto_function_symbol_mode;
48  return function_call_site_symbol;
49  }());
50 
51  auto const new_function_pointer =
52  goto_model.symbol_table.lookup_ref(call_site_symbol_name)
53  .symbol_expr();
54 
55  // add assignment to the new function pointer variable, followed by a
56  // call of the new variable
57  auto assign_instruction = goto_programt::make_assignment(
58  code_assignt{new_function_pointer,
59  function_pointer_dereference.pointer()},
60  source_location);
61 
62  goto_function.second.body.insert_before_swap(it, assign_instruction);
63  const auto next = std::next(it);
64  to_code_function_call(next->code).function() =
65  dereference_exprt{new_function_pointer};
66  // we need to increment the iterator once more (in addition to the
67  // increment already done by for_each_goto_function_if()). This is
68  // because insert_before_swap() inserts a new instruction after the
69  // instruction pointed to by it (and then swaps the contents with the
70  // previous instruction). We need to increment the iterator as we also
71  // need to skip over this newly inserted instruction.
72  it++;
73  });
74  }
75 }
symbol_table_baset::lookup_ref
const symbolt & lookup_ref(const irep_idt &name) const
Find a symbol in the symbol table for read-only access.
Definition: symbol_table_base.h:104
fresh_symbol.h
Fresh auxiliary symbol creation.
dereference_exprt
Operator to dereference a pointer.
Definition: pointer_expr.h:256
for_each_instruction_if
void for_each_instruction_if(GotoFunctionT &&goto_function, PredicateT predicate, HandlerT handler)
Definition: goto_program.h:1144
label_function_pointer_call_sites
void label_function_pointer_call_sites(goto_modelt &goto_model)
This ensures that call instructions can be only one of two things:
Definition: label_function_pointer_call_sites.cpp:14
goto_modelt
Definition: goto_model.h:26
goto_functionst::function_map
function_mapt function_map
Definition: goto_functions.h:27
goto_programt::make_assignment
static instructiont make_assignment(const code_assignt &_code, const source_locationt &l=source_locationt::nil())
Create an assignment instruction.
Definition: goto_program.h:995
symbolt::symbol_expr
class symbol_exprt symbol_expr() const
Produces a symbol_exprt for a symbol.
Definition: symbol.cpp:122
pointer_expr.h
API to expression classes for Pointers.
symbol_tablet::insert
virtual std::pair< symbolt &, bool > insert(symbolt symbol) override
Author: Diffblue Ltd.
Definition: symbol_table.cpp:19
to_code_function_call
const code_function_callt & to_code_function_call(const codet &code)
Definition: std_code.h:1326
goto_modelt::goto_functions
goto_functionst goto_functions
GOTO functions.
Definition: goto_model.h:33
code_assignt
A codet representing an assignment in the program.
Definition: std_code.h:295
label_function_pointer_call_sites.h
Label function pointer call sites across a goto model.
goto_modelt::symbol_table
symbol_tablet symbol_table
Symbol table.
Definition: goto_model.h:30
goto_programt::targett
instructionst::iterator targett
Definition: goto_program.h:550
code_function_callt::function
exprt & function()
Definition: std_code.h:1250