Expr vc_bvWriteToMemoryArray(VC vc,
Expr array, Expr byteIndex,
Expr element, int numOfBytes) {
if(!(numOfBytes > 0))
BEEV::FatalError("numOfBytes must be greater than 0");
int newBitsPerElem = numOfBytes*8;
if(numOfBytes == 1)
return vc_writeExpr(vc, array, byteIndex, element);
else {
int count = 1;
int hi = newBitsPerElem - 1;
int low = newBitsPerElem - 8;
int low_elem = 0;
int hi_elem = low_elem + 7;
Expr c = vc_bvExtract(vc, element, hi_elem, low_elem);
Expr newarray = vc_writeExpr(vc, array, byteIndex, c);
while(--numOfBytes > 0) {
hi = low-1;
low = low-8;
low_elem = low_elem + 8;
hi_elem = low_elem + 7;
c = vc_bvExtract(vc, element, hi_elem, low_elem);
newarray =
vc_writeExpr(vc, newarray,
vc_bvPlusExpr(vc, 32, byteIndex, vc_bvConstExprFromInt(vc,32,count)),
c);
count++;
}
return newarray;
}
}
int main(int argc, char** argv)
{
int width=8;
VC handle = vc_createValidityChecker();
// Create variable "x"
Expr x = vc_varExpr(handle, "x", vc_bvType(handle, width));
// Create bitvector x + x
Expr xPlusx = vc_bvPlusExpr(handle, width, x, x);
// Create bitvector constant 2
Expr two = vc_bvConstExprFromInt(handle, width, 2);
// Create bitvector 2*x
Expr xTimes2 = vc_bvMultExpr(handle, width, two, x);
// Create bool expression x + x = 2*x
Expr equality = vc_eqExpr(handle, xPlusx , xTimes2);
vc_assertFormula(handle, vc_trueExpr(handle) );
// We are asking STP: ∀ x. true → ( x + x = 2*x )
// This should be VALID.
printf("######First Query\n");
handleQuery(handle, equality);
// We are asking STP: ∀ x. true → ( x + x = 2 )
// This should be INVALID.
printf("######Second Query\n");
// Create bool expression x + x = 2
Expr badEquality = vc_eqExpr(handle, xPlusx , two);
handleQuery(handle, badEquality);
// Clean up
vc_Destroy(handle);
return 0;
}
Expr vc_bvReadMemoryArray(VC vc,
Expr array,
Expr byteIndex, int numOfBytes) {
if(!(numOfBytes > 0))
BEEV::FatalError("numOfBytes must be greater than 0");
if(numOfBytes == 1)
return vc_readExpr(vc,array,byteIndex);
else {
int count = 1;
Expr a = vc_readExpr(vc,array,byteIndex);
while(--numOfBytes > 0) {
Expr b = vc_readExpr(vc,array,
/*vc_simplify(vc, */
vc_bvPlusExpr(vc, 32,
byteIndex,
vc_bvConstExprFromInt(vc,32,count)))/*)*/;
a = vc_bvConcatExpr(vc,b,a);
count++;
}
return a;
}
}
TEST(extend_adder_notexpr, one)
{
VC vc = vc_createValidityChecker();
vc_setFlags(vc, 'n');
vc_setFlags(vc, 'd');
// 8-bit variable 'x'
Expr x = vc_varExpr(vc, "x", vc_bvType(vc, 8));
// 32 bit constant value 1
Expr one = vc_bvConstExprFromInt(vc, 32, 1);
// 24 bit constant value 0
Expr bit24_zero = vc_bvConstExprFromInt(vc, 24, 0);
// 32 bit constant value 0
Expr bit32_zero = vc_bvConstExprFromInt(vc, 32, 0);
// Extending 8-bit variable to 32-bit value
Expr zero_concat_x = vc_bvConcatExpr(vc, bit24_zero, x);
Expr xp1 = vc_bvPlusExpr(vc, 32, zero_concat_x, one);
// Insteading of concat operation, I also tried with SignExtend
// Expr signextend_x=vc_bvSignExtend(vc,x,32);
// Expr xp1=vc_bvPlusExpr(vc,32,signextend_x,one);
// x+1=0
Expr eq = vc_eqExpr(vc, xp1, bit32_zero);
// x+1!=0
eq = vc_notExpr(vc, eq);
vc_query(vc, eq);
vc_printCounterExample(vc);
// FIXME: Actually test something
// ASSERT_TRUE(false && "FIXME: Actually test something");
}
Expr vc_bv32PlusExpr(VC vc, Expr left, Expr right) {
return vc_bvPlusExpr(vc, 32, left, right);
}
TEST(reported_issue_120, one)
{
VC vc = vc_createValidityChecker();
// Numbers will be non-negatives integers bounded at 2^32
Type bv32 = vc_bvType(vc, 32);
// Determine whether the following equations are satisfiable:
// v + 4 = n
// 4 = n
// Construct variable n
Expr n = vc_varExpr(vc, "n", bv32);
// Construct v + 4
Expr v = vc_varExpr(vc, "v", bv32);
Expr ct_4 = vc_bvConstExprFromInt(vc, 32, 4);
Expr add_v_4 = vc_bvPlusExpr(vc, 32, v, ct_4);
// Because numbers are represented as bit vectors,
// addition can roll over. So construct a constraint
// expresses that v+4 does not overflow the bounds:
// v + 4 >= v
//
Expr ge = vc_bvGeExpr(vc, add_v_4, v);
// Push a new context
printf("Push\n");
vc_push(vc);
// Assert v + 4 = n
printf("Assert v + 4 = n\n");
Expr f_add = vc_eqExpr(vc, add_v_4, n);
vc_assertFormula(vc, f_add);
vc_printExpr(vc, f_add);
printf("\n------\n");
// Assert the bounds constraint
printf("Assert v + 4 >= v\n");
vc_assertFormula(vc, ge);
vc_printExpr(vc, ge);
printf("\n------\n");
// Assert 4 = n
printf("Assert 4 = n\n");
Expr f_numeq = vc_eqExpr(vc, ct_4, n);
vc_assertFormula(vc, f_numeq);
vc_printExpr(vc, f_numeq);
printf("\n------\n");
// Check for satisfiability
printf("Check\n");
vc_printAsserts(vc);
printf("\n------\n");
int query = vc_query(vc, vc_falseExpr(vc));
ASSERT_EQ(query, 0);
// Pop context
printf("Pop\n");
vc_pop(vc);
printf("query = %d\n", query);
}
value caml_vc_bvPlusExpr(value vc, value bits, value e1, value e2)
{
CAMLparam4(vc,bits,e1,e2);
CAMLreturn(alloc_Expr(vc_bvPlusExpr(VC_val(vc),Int_val(bits),
Expr_val(e1),Expr_val(e2))));
}
