cprover
label_function_pointer_call_sites.cpp
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1/*******************************************************************\
2Module: Label function pointer call sites
3Author: Diffblue Ltd.
4\*******************************************************************/
5
8
10
11#include <util/pointer_expr.h>
12
13#include "goto_model.h"
14
16{
17 for(auto &goto_function : goto_model.goto_functions.function_map)
18 {
19 std::size_t function_pointer_call_counter = 0;
20
22 goto_function.second,
23 [](const goto_programt::targett it) {
24 return it->is_function_call() &&
25 can_cast_expr<dereference_exprt>(it->call_function());
26 },
27 [&](goto_programt::targett &it) {
28 auto const &function_pointer_dereference =
29 to_dereference_expr(it->call_function());
30 auto const &source_location = it->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 = it->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 a DECL instruction for the function pointer variable
56 auto decl_instruction =
57 goto_programt::make_decl(new_function_pointer, source_location);
58
59 goto_function.second.body.insert_before_swap(it, decl_instruction);
60 ++it;
61
62 // add assignment to the new variable
63 auto assign_instruction = goto_programt::make_assignment(
64 code_assignt{new_function_pointer,
65 function_pointer_dereference.pointer()},
66 source_location);
67
68 goto_function.second.body.insert_before_swap(it, assign_instruction);
69 ++it;
70
71 // transform original call into a call to the new variable
72 it->call_function() = dereference_exprt{new_function_pointer};
73 ++it;
74
75 // add a DEAD instruction for the new variable
76 auto dead_instruction =
77 goto_programt::make_dead(new_function_pointer, source_location);
78 goto_function.second.body.insert_before_swap(it, dead_instruction);
79 // the iterator now points to the DEAD instruction and will be
80 // incremented by the outer loop
81 });
82 }
83}
A codet representing an assignment in the program.
Operator to dereference a pointer.
Definition: pointer_expr.h:648
function_mapt function_map
symbol_tablet symbol_table
Symbol table.
Definition: goto_model.h:30
goto_functionst goto_functions
GOTO functions.
Definition: goto_model.h:33
const exprt & call_function() const
Get the function that is called for FUNCTION_CALL.
Definition: goto_program.h:271
static instructiont make_dead(const symbol_exprt &symbol, const source_locationt &l=source_locationt::nil())
Definition: goto_program.h:956
instructionst::iterator targett
Definition: goto_program.h:592
static instructiont make_assignment(const code_assignt &_code, const source_locationt &l=source_locationt::nil())
Create an assignment instruction.
static instructiont make_decl(const symbol_exprt &symbol, const source_locationt &l=source_locationt::nil())
Definition: goto_program.h:949
const symbolt & lookup_ref(const irep_idt &name) const
Find a symbol in the symbol table for read-only access.
virtual std::pair< symbolt &, bool > insert(symbolt symbol) override
Author: Diffblue Ltd.
class symbol_exprt symbol_expr() const
Produces a symbol_exprt for a symbol.
Definition: symbol.cpp:121
Symbol Table + CFG.
void for_each_instruction_if(GotoFunctionT &&goto_function, PredicateT predicate, HandlerT handler)
void label_function_pointer_call_sites(goto_modelt &goto_model)
This ensures that call instructions can be only one of two things:
Label function pointer call sites across a goto model.
API to expression classes for Pointers.