CProver manual
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The following sections summarize the functions available to programs that are passed to the CPROVER tools.
The function **__CPROVER_assume** adds an expression as a constraint to the program. If the expression evaluates to false, the execution aborts without failure. More detail on the use of assumptions is in the section on Assumptions.
The functions **__CPROVER_input** and **__CPROVER_output** are used to report an input or output value. Note that they do not generate input or output values. The first argument is a string constant to distinguish multiple inputs and outputs (inputs are typically generated using nondeterminism, as described here). The string constant is followed by an arbitrary number of values of arbitrary types.
The function **__CPROVER_printf** implements the C printf
function (without any return value). The observable effect is that its output is shown within a counterexample trace.
This statement defines a custom coverage criterion, for usage with the test suite generation feature.
The function **__CPROVER_isnan** returns true if the double-precision floating-point number passed as argument is a NaN.
The function **__CPROVER_isfinite** returns true if the double-precision floating-point number passed as argument is a finite number.
This function **__CPROVER_isinf** returns true if the double-precision floating-point number passed as argument is plus or minus infinity.
The function **__CPROVER_isnormal** returns true if the double-precision floating-point number passed as argument is a normal number.
This function **__CPROVER_sign** returns true if the double-precision floating-point number passed as argument is negative.
These functions return the absolute value of the given argument.
These functions take two (__CPROVER_overflow_unary_minus
only takes one) arguments of any numeric type. They return true, if, and only if, the named operation would overflow when applied to the arguments. For example, __CPROVER_overflow_plus(x, y)
returns true if x + y
would result in an arithmetic overflow.
The function **__CPROVER_array_equal** returns true if the values stored in the given arrays are equal. The function **__CPROVER_array_copy** copies the contents of the array src to the array dest. The function **__CPROVER_array_set** initializes the array dest with the given value.
The function **__CPROVER_enum_is_in_range** is used to check that an enumeration has one of the defined enumeration values. In the following example __CPROVER_enum_is_in_range(ev1)
will return true and the assertion will pass
However, in the example below the assertion will fail
Uninterpreted functions are documented here.
The semantics of the primitives listed in this section is described in more detail in the document about Memory Primitives.
The function **__CPROVER_POINTER_OBJECT** returns the ID of the object the pointer points to. The function **__CPROVER_POINTER_OFFSET** returns the offset of the given pointer relative to the base address of the object. The function **__CPROVER_same_object** returns true if the two pointers given as arguments point to the same object.
The following primitives require a pointer that is null or valid in order to have well-defined semantics in all usage cases. See the document about Memory Primitives for more details. It also includes a description of the --pointer-primitive-check
option to verify the preconditions of the primitives.
The function **__CPROVER__OBJECT_SIZE** returns the size of the object the given pointer points to. The function **__CPROVER_DYNAMIC_OBJECT** returns true if the pointer passed as an argument points to a dynamically allocated object.
The function **__CPROVER_r_ok** returns true if reading the piece of memory starting at the given pointer with the given size is safe. **__CPROVER_w_ok** does the same with writing, and **__CPROVER_rw_ok** returns true when it is safe to do both. These predicates can be given an optional size; when the size argument is not given, the size of the subtype (which must not be void) of the pointer type is used.
This function requires a valid pointer and updates all bytes of the underlying object with nondeterministic values.
Warning
This primitive havocs object bytes before the given p
and after p + sizeof(*p)
:
This function requires requires that __CPROVER_w_ok(p, size)
holds, and updates size
consecutive bytes of the underlying object, starting at p
, with nondeterministic values.
Caveat
This type is only available in the C frontend. It is used to specify a bit vector with arbitrary but fixed size. The usual integer type modifiers signed and unsigned can be applied. The usual arithmetic promotions will be applied to operands of this type.
This type is only available in the C frontend. It is used to specify an IEEE-754 floating point number with arbitrary but fixed size. The first parameter is the total size (in bits) of the number, and the second is the size (in bits) of the mantissa, or significand (not including the hidden bit, thus for single precision this should be 23).
This type is only available in the C frontend. It is used to specify a fixed-point bit vector with arbitrary but fixed size. The first parameter is the total size (in bits) of the type, and the second is the number of bits after the radix point.
The type of sizeof expressions.
This variable contains the IEEE floating-point arithmetic rounding mode.
This is a constant that models a large unsigned integer.
**__CPROVER_integer** is an unbounded, signed integer type. **__CPROVER_rational** is an unbounded, signed rational number type.
This array models the contents of integer-addressed memory.
This type is the equivalent of unsigned __CPROVER_bitvector[N] in the C++ front-end.
This type is the equivalent of signed __CPROVER_bitvector[N] in the C++ front-end.
This type is the equivalent of **__CPROVER_fixedbv[N,m]** in the C++ front-end.
Asynchronous threads are created by preceding an instruction with a label with the prefix **__CPROVER_ASYNC_**.
Last modified: 2024-11-12 09:30:37 +0200