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Merged
merged 4 commits into from
Sep 30, 2024
Merged

unchecked_mul and unchecked_shr proofs #7

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bbd75f7
unchecked multiplication and shift right
rajathkotyal Sep 23, 2024
864afa6
Small fix typo
rajathkotyal Sep 25, 2024
ae678de
added limits to multiplication proofs, reduced duplicacy in code by u…
rajathkotyal Sep 29, 2024
af6942e
Merge branch 'c-0011-core-nums-yenyunw-unsafe-ints' into c-0011-core-…
rajathkotyal Sep 29, 2024
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2 changes: 2 additions & 0 deletions library/core/src/num/int_macros.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -816,6 +816,7 @@ macro_rules! int_impl {
without modifying the original"]
#[inline(always)]
#[cfg_attr(miri, track_caller)] // even without panics, this helps for Miri backtraces
#[requires(!self.overflowing_mul(rhs).1)]
pub const unsafe fn unchecked_mul(self, rhs: Self) -> Self {
assert_unsafe_precondition!(
check_language_ub,
Expand Down Expand Up @@ -1424,6 +1425,7 @@ macro_rules! int_impl {
#[rustc_const_unstable(feature = "unchecked_shifts", issue = "85122")]
#[inline(always)]
#[cfg_attr(miri, track_caller)] // even without panics, this helps for Miri backtraces
#[requires(rhs < <$ActualT>::BITS)] // i.e. requires the right hand side of the shift (rhs) to be less than the number of bits in the type. This prevents undefined behavior.
pub const unsafe fn unchecked_shr(self, rhs: u32) -> Self {
assert_unsafe_precondition!(
check_language_ub,
Expand Down
72 changes: 71 additions & 1 deletion library/core/src/num/mod.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -1605,19 +1605,39 @@ mod verify {
}
}

macro_rules! generate_unchecked_mul_harness {
($type:ty, $method:ident, $harness_name:ident, $min:expr, $max:expr) => {
#[kani::proof_for_contract($type::$method)]
pub fn $harness_name() {
let num1: $type = kani::any();
let num2: $type = kani::any();

// Limit the values of num1 and num2 to the specified range for multiplication
kani::assume(num1 >= $min && num1 <= $max);
kani::assume(num2 >= $min && num2 <= $max);

unsafe {
num1.$method(num2);
}
}
}
}


macro_rules! generate_unchecked_shift_harness {
($type:ty, $method:ident, $harness_name:ident) => {
#[kani::proof_for_contract($type::$method)]
pub fn $harness_name() {
let num1: $type = kani::any::<$type>();
let num2: u32 = kani::any::<u32>();

unsafe {
num1.$method(num2);
}
}
}
}


macro_rules! generate_unchecked_neg_harness {
($type:ty, $method:ident, $harness_name:ident) => {
Expand Down Expand Up @@ -1654,4 +1674,54 @@ mod verify {
generate_unchecked_math_harness!(u64, unchecked_add, checked_unchecked_add_u64);
generate_unchecked_math_harness!(u128, unchecked_add, checked_unchecked_add_u128);
generate_unchecked_math_harness!(usize, unchecked_add, checked_unchecked_add_usize);

// unchecked_mul proofs
//
// Target types:
// i{8,16,32,64,128, size} and u{8,16,32,64,128, size} -- 12 types in total
//
// Target contracts:
// #[requires(!self.overflowing_mul(rhs).1)]
//
// Target function:
// pub const unsafe fn unchecked_mul(self, rhs: Self) -> Self
// exponential state spaces for 32,64 and 128, hence provided limited range for verification.
generate_unchecked_math_harness!(i8, unchecked_mul, checked_unchecked_mul_i8);
generate_unchecked_math_harness!(i16, unchecked_mul, checked_unchecked_mul_i16);
generate_unchecked_mul_harness!(i32, unchecked_mul, checked_unchecked_mul_i32, -10_000i32, 10_000i32);
generate_unchecked_mul_harness!(i64, unchecked_mul, checked_unchecked_mul_i64, -1_000i64, 1_000i64);
generate_unchecked_mul_harness!(i128, unchecked_mul, checked_unchecked_mul_i128, -1_000_000_000_000_000i128, 1_000_000_000_000_000i128);
generate_unchecked_mul_harness!(isize, unchecked_mul, checked_unchecked_mul_isize, -100_000isize, 100_000isize);
generate_unchecked_math_harness!(u8, unchecked_mul, checked_unchecked_mul_u8);
generate_unchecked_math_harness!(u16, unchecked_mul, checked_unchecked_mul_u16);
generate_unchecked_mul_harness!(u32, unchecked_mul, checked_unchecked_mul_u32, 0u32, 20_000u32);
generate_unchecked_mul_harness!(u64, unchecked_mul, checked_unchecked_mul_u64, 0u64, 2_000u64);
generate_unchecked_mul_harness!(u128, unchecked_mul, checked_unchecked_mul_u128, 0u128, 1_000_000_000_000_000u128);
generate_unchecked_mul_harness!(usize, unchecked_mul, checked_unchecked_mul_usize, 0usize, 100_000usize);


// unchecked_shr proofs
//
// Target types:
// i{8,16,32,64,128,size} and u{8,16,32,64,128,size} -- 12 types in total
//
// Target contracts:
// #[requires(rhs < <$ActualT>::BITS)]
//
// Target function:
// pub const unsafe fn unchecked_shr(self, rhs: u32) -> Self
generate_unchecked_shift_harness!(i8, unchecked_shr, checked_unchecked_shr_i8);
generate_unchecked_shift_harness!(i16, unchecked_shr, checked_unchecked_shr_i16);
generate_unchecked_shift_harness!(i32, unchecked_shr, checked_unchecked_shr_i32);
generate_unchecked_shift_harness!(i64, unchecked_shr, checked_unchecked_shr_i64);
generate_unchecked_shift_harness!(i128, unchecked_shr, checked_unchecked_shr_i128);
generate_unchecked_shift_harness!(isize, unchecked_shr, checked_unchecked_shr_isize);
generate_unchecked_shift_harness!(u8, unchecked_shr, checked_unchecked_shr_u8);
generate_unchecked_shift_harness!(u16, unchecked_shr, checked_unchecked_shr_u16);
generate_unchecked_shift_harness!(u32, unchecked_shr, checked_unchecked_shr_u32);
generate_unchecked_shift_harness!(u64, unchecked_shr, checked_unchecked_shr_u64);
generate_unchecked_shift_harness!(u128, unchecked_shr, checked_unchecked_shr_u128);
generate_unchecked_shift_harness!(usize, unchecked_shr, checked_unchecked_shr_usize);
}
}
}
2 changes: 2 additions & 0 deletions library/core/src/num/uint_macros.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -908,6 +908,7 @@ macro_rules! uint_impl {
without modifying the original"]
#[inline(always)]
#[cfg_attr(miri, track_caller)] // even without panics, this helps for Miri backtraces
#[requires(!self.overflowing_mul(rhs).1)]
pub const unsafe fn unchecked_mul(self, rhs: Self) -> Self {
assert_unsafe_precondition!(
check_language_ub,
Expand Down Expand Up @@ -1613,6 +1614,7 @@ macro_rules! uint_impl {
#[rustc_const_unstable(feature = "unchecked_shifts", issue = "85122")]
#[inline(always)]
#[cfg_attr(miri, track_caller)] // even without panics, this helps for Miri backtraces
#[requires(rhs < <$ActualT>::BITS)]// i.e. requires the right hand side of the shift (rhs) to be less than the number of bits in the type. This prevents undefined behavior.
pub const unsafe fn unchecked_shr(self, rhs: u32) -> Self {
assert_unsafe_precondition!(
check_language_ub,
Expand Down