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Instrument strchr to use the string refinement solver #5200

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Instrument strchr to use the string refinement solver #5200

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941eed4
Add c-specific refinement utils
hannes-steffenhagen-diffblue Feb 7, 2020
8d82639
Extend index-of for c
hannes-steffenhagen-diffblue Feb 7, 2020
3f76f13
Implement strchr in terms of index-of
petr-bauch Feb 7, 2020
80c88cc
Handle the c-specific cases in string refinement
petr-bauch Feb 7, 2020
ddf72d1
Add tests for strchr
petr-bauch Feb 7, 2020
0879ad0
Add case for byte-extracting arrays
petr-bauch Feb 7, 2020
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15 changes: 15 additions & 0 deletions regression/cbmc/string-refinement-strchr1/test.c
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Original file line number Diff line number Diff line change
@@ -0,0 +1,15 @@
#include <assert.h>
#include <string.h>

int main()
{
char test[] = "foo";

char *first_o = strchr(test, 'o');
assert(*first_o == test[1]);
assert(*first_o == test[0]);
char *first_t = strchr(test, 't');
assert(*first_t == test[1]);
assert(*first_t == test[0]);
return 0;
}
12 changes: 12 additions & 0 deletions regression/cbmc/string-refinement-strchr1/test.desc
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CORE broken-smt-backend
test.c
--refine-strings --max-nondet-string-length 10
^EXIT=10$
^SIGNAL=0$
^\[main.assertion.\d+\] line \d+ assertion \*first_o == test\[1\]: SUCCESS$
^\[main.assertion.\d+\] line \d+ assertion \*first_o == test\[0\]: FAILURE$
^\[main.assertion.\d+\] line \d+ assertion \*first_t == test\[1\]: FAILURE$
^\[main.assertion.\d+\] line \d+ assertion \*first_t == test\[0\]: FAILURE$
^VERIFICATION FAILED$
--
^warning: ignoring
13 changes: 13 additions & 0 deletions regression/cbmc/string-refinement-strchr2/test.c
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@@ -0,0 +1,13 @@
#include <assert.h>
#include <string.h>

int main()
{
int i;
char *test = i ? "fo\0tis" : "notfoti";
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There should be a test for the case when a character can’t be found as well, e.g. in this case 't' may or may not be found depending on i.


char *first_o = strchr(test, 'o');
assert(first_o != NULL);
assert(*first_o == test[0]);
return 0;
}
10 changes: 10 additions & 0 deletions regression/cbmc/string-refinement-strchr2/test.desc
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@@ -0,0 +1,10 @@
CORE broken-smt-backend
test.c
--refine-strings
^EXIT=10$
^SIGNAL=0$
^\[main.assertion.\d+\] line \d+ assertion first_o != (NULL|\(\(void \*\)0\)): SUCCESS$
^\[main.assertion.\d+\] line \d+ assertion \*first_o == test\[0\]: FAILURE$
^VERIFICATION FAILED$
--
^warning: ignoring
12 changes: 10 additions & 2 deletions src/cbmc/cbmc_parse_options.cpp
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Expand Up @@ -362,6 +362,9 @@ void cbmc_parse_optionst::get_command_line_options(optionst &options)
{
options.set_option("refine-strings", true);
options.set_option("string-printable", cmdline.isset("string-printable"));
options.set_option(
"max-nondet-string-length",
cmdline.get_value("max-nondet-string-length"));
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Does this need a default value as is in jbmc? MAX_CONCRETE_STRING_SIZE - 1

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Also note jbmc throws an error if you use this option without --refine-strings

}

if(cmdline.isset("max-node-refinement"))
Expand Down Expand Up @@ -830,8 +833,13 @@ bool cbmc_parse_optionst::process_goto_program(
link_to_library(
goto_model, log.get_message_handler(), cprover_c_library_factory);

if(options.get_bool_option("string-abstraction"))
string_instrumentation(goto_model, log.get_message_handler());
if(
options.get_bool_option("string-abstraction") ||
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Maybe I am getting mixed up but I thought the "string-abstraction" options did something very different? Maybe that was in goto-instrument.

options.get_bool_option("refine-strings"))
string_instrumentation(
goto_model,
log.get_message_handler(),
options.get_option("max-nondet-string-length"));

// remove function pointers
log.status() << "Removal of function pointers and virtual functions"
Expand Down
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