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Merge pull request #2854 from diffblue/union-valueset-bug 

added a test for the precision of the value sets on unions
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Michael Tautschnig 2018-09-04 12:06:38 +01:00 committed by GitHub
parent 84170dfe02 9638dbb38c
commit 0ec4e7dc86
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2 changed files with 49 additions and 0 deletions
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31
regression/cbmc/union10/union_list2.c Normal file
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@ -0,0 +1,31 @@
#include <assert.h>
struct list_item
{
unsigned value;
struct list_item *previous;
};
struct List
{
unsigned something;
struct list_item * index, end;
};
union U
{
struct List my_list;
};
int main()
{
union U u;
u.my_list.index = &u.my_list.end;
struct list_item *p0 = u.my_list.index;
u.my_list.end.value = 123;
u.my_list.end.previous = u.my_list.index;
struct list_item *p1 = u.my_list.index;
struct list_item *p2 = p1->previous;
assert(p2 != 0); // should pass
}

18
regression/cbmc/union10/union_list2.desc Normal file
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@ -0,0 +1,18 @@
KNOWNBUG
union_list2.c
^EXIT=0$
^SIGNAL=0$
^VERIFICATION SUCCESSFUL$
--
^warning: ignoring
--
Value sets do not record byte-extract operations with sufficient detail:
struct list_item *p1 = u.my_list.index;
struct list_item *p2 = p1->previous;
yields
(29) p1!0@1#2 == byte_extract_little_endian(u!0@1#4, 8l, struct list_item { unsigned int value; unsigned int $pad1; struct list_item *previous; } *)
(30) p2!0@1#2 == p1$object#0.previous
as
main::1::p1 = { <integer_address, *, unsigned char> }
is the only information stored in the value set.