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feat: add tests for shift instructions (bluealloy#1254)
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* feat: add tests for shift instructions

* Use LatestSpec instead of CancunSpec

* Run cargo fmt

* Use parans instead of brackets

* Simplify host/interpreter initialization

* Remove unused imports

* Remove test case comments

* Use U256 types
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@jtraglia
jtraglia committed Apr 2, 2024
1 parent c3f0503 commit 52f1f01
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Showing 2 changed files with 284 additions and 3 deletions.
2 changes: 1 addition & 1 deletion bins/revm-test/src/bin/analysis.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -25,7 +25,7 @@ fn main() {
.with_db(BenchmarkDB::new_bytecode(bytecode_raw))
.build();

// just to spead up processor.
// Just to warm up the processor.
for _ in 0..10000 {
let _ = evm.transact().unwrap();
}
Expand Down
285 changes: 283 additions & 2 deletions crates/interpreter/src/instructions/bitwise.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -5,6 +5,7 @@ use crate::{
Host, Interpreter,
};
use core::cmp::Ordering;
use revm_primitives::uint;

pub fn lt<H: Host>(interpreter: &mut Interpreter, _host: &mut H) {
gas!(interpreter, gas::VERYLOW);
Expand Down Expand Up @@ -103,19 +104,299 @@ pub fn sar<H: Host, SPEC: Spec>(interpreter: &mut Interpreter, _host: &mut H) {

let value_sign = i256_sign_compl(op2);

*op2 = if value_sign == Sign::Zero || op1 >= U256::from(256) {
// If the shift count is 255+, we can short-circuit. This is because shifting by 255 bits is the
// maximum shift that still leaves 1 bit in the original 256-bit number. Shifting by 256 bits or
// more would mean that no original bits remain. The result depends on what the highest bit of
// the value is.
*op2 = if value_sign == Sign::Zero || op1 >= U256::from(255) {
match value_sign {
// value is 0 or >=1, pushing 0
Sign::Plus | Sign::Zero => U256::ZERO,
// value is <0, pushing -1
Sign::Minus => U256::MAX,
}
} else {
const ONE: U256 = U256::from_limbs([1, 0, 0, 0]);
const ONE: U256 = uint!(1_U256);
// SAFETY: shift count is checked above; it's less than 255.
let shift = usize::try_from(op1).unwrap();
match value_sign {
Sign::Plus | Sign::Zero => op2.wrapping_shr(shift),
Sign::Minus => two_compl(op2.wrapping_sub(ONE).wrapping_shr(shift).wrapping_add(ONE)),
}
};
}

#[cfg(test)]
mod tests {
use crate::instructions::bitwise::{sar, shl, shr};
use crate::{Contract, DummyHost, Interpreter};
use revm_primitives::{uint, Env, LatestSpec, U256};

#[test]
fn test_shift_left() {
let mut host = DummyHost::new(Env::default());
let mut interpreter = Interpreter::new(Contract::default(), u64::MAX, false);

struct TestCase {
value: U256,
shift: U256,
expected: U256,
}

uint! {
let test_cases = [
TestCase {
value: 0x0000000000000000000000000000000000000000000000000000000000000001_U256,
shift: 0x00_U256,
expected: 0x0000000000000000000000000000000000000000000000000000000000000001_U256,
},
TestCase {
value: 0x0000000000000000000000000000000000000000000000000000000000000001_U256,
shift: 0x01_U256,
expected: 0x0000000000000000000000000000000000000000000000000000000000000002_U256,
},
TestCase {
value: 0x0000000000000000000000000000000000000000000000000000000000000001_U256,
shift: 0xff_U256,
expected: 0x8000000000000000000000000000000000000000000000000000000000000000_U256,
},
TestCase {
value: 0x0000000000000000000000000000000000000000000000000000000000000001_U256,
shift: 0x0100_U256,
expected: 0x0000000000000000000000000000000000000000000000000000000000000000_U256,
},
TestCase {
value: 0x0000000000000000000000000000000000000000000000000000000000000001_U256,
shift: 0x0101_U256,
expected: 0x0000000000000000000000000000000000000000000000000000000000000000_U256,
},
TestCase {
value: 0xffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff_U256,
shift: 0x00_U256,
expected: 0xffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff_U256,
},
TestCase {
value: 0xffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff_U256,
shift: 0x01_U256,
expected: 0xfffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffe_U256,
},
TestCase {
value: 0xffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff_U256,
shift: 0xff_U256,
expected: 0x8000000000000000000000000000000000000000000000000000000000000000_U256,
},
TestCase {
value: 0xffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff_U256,
shift: 0x0100_U256,
expected: 0x0000000000000000000000000000000000000000000000000000000000000000_U256,
},
TestCase {
value: 0x0000000000000000000000000000000000000000000000000000000000000000_U256,
shift: 0x01_U256,
expected: 0x0000000000000000000000000000000000000000000000000000000000000000_U256,
},
TestCase {
value: 0x7fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff_U256,
shift: 0x01_U256,
expected: 0xfffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffe_U256,
},
];
}

for test in test_cases {
host.clear();
push!(interpreter, test.value);
push!(interpreter, test.shift);
shl::<DummyHost, LatestSpec>(&mut interpreter, &mut host);
pop!(interpreter, res);
assert_eq!(res, test.expected);
}
}

#[test]
fn test_logical_shift_right() {
let mut host = DummyHost::new(Env::default());
let mut interpreter = Interpreter::new(Contract::default(), u64::MAX, false);

struct TestCase {
value: U256,
shift: U256,
expected: U256,
}

uint! {
let test_cases = [
TestCase {
value: 0x0000000000000000000000000000000000000000000000000000000000000001_U256,
shift: 0x00_U256,
expected: 0x0000000000000000000000000000000000000000000000000000000000000001_U256,
},
TestCase {
value: 0x0000000000000000000000000000000000000000000000000000000000000001_U256,
shift: 0x01_U256,
expected: 0x0000000000000000000000000000000000000000000000000000000000000000_U256,
},
TestCase {
value: 0x8000000000000000000000000000000000000000000000000000000000000000_U256,
shift: 0x01_U256,
expected: 0x4000000000000000000000000000000000000000000000000000000000000000_U256,
},
TestCase {
value: 0x8000000000000000000000000000000000000000000000000000000000000000_U256,
shift: 0xff_U256,
expected: 0x0000000000000000000000000000000000000000000000000000000000000001_U256,
},
TestCase {
value: 0x8000000000000000000000000000000000000000000000000000000000000000_U256,
shift: 0x0100_U256,
expected: 0x0000000000000000000000000000000000000000000000000000000000000000_U256,
},
TestCase {
value: 0x8000000000000000000000000000000000000000000000000000000000000000_U256,
shift: 0x0101_U256,
expected: 0x0000000000000000000000000000000000000000000000000000000000000000_U256,
},
TestCase {
value: 0xffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff_U256,
shift: 0x00_U256,
expected: 0xffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff_U256,
},
TestCase {
value: 0xffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff_U256,
shift: 0x01_U256,
expected: 0x7fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff_U256,
},
TestCase {
value: 0xffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff_U256,
shift: 0xff_U256,
expected: 0x0000000000000000000000000000000000000000000000000000000000000001_U256,
},
TestCase {
value: 0xffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff_U256,
shift: 0x0100_U256,
expected: 0x0000000000000000000000000000000000000000000000000000000000000000_U256,
},
TestCase {
value: 0x0000000000000000000000000000000000000000000000000000000000000000_U256,
shift: 0x01_U256,
expected: 0x0000000000000000000000000000000000000000000000000000000000000000_U256,
},
];
}

for test in test_cases {
host.clear();
push!(interpreter, test.value);
push!(interpreter, test.shift);
shr::<DummyHost, LatestSpec>(&mut interpreter, &mut host);
pop!(interpreter, res);
assert_eq!(res, test.expected);
}
}

#[test]
fn test_arithmetic_shift_right() {
let mut host = DummyHost::new(Env::default());
let mut interpreter = Interpreter::new(Contract::default(), u64::MAX, false);

struct TestCase {
value: U256,
shift: U256,
expected: U256,
}

uint! {
let test_cases = [
TestCase {
value: 0x0000000000000000000000000000000000000000000000000000000000000001_U256,
shift: 0x00_U256,
expected: 0x0000000000000000000000000000000000000000000000000000000000000001_U256,
},
TestCase {
value: 0x0000000000000000000000000000000000000000000000000000000000000001_U256,
shift: 0x01_U256,
expected: 0x0000000000000000000000000000000000000000000000000000000000000000_U256,
},
TestCase {
value: 0x8000000000000000000000000000000000000000000000000000000000000000_U256,
shift: 0x01_U256,
expected: 0xc000000000000000000000000000000000000000000000000000000000000000_U256,
},
TestCase {
value: 0x8000000000000000000000000000000000000000000000000000000000000000_U256,
shift: 0xff_U256,
expected: 0xffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff_U256,
},
TestCase {
value: 0x8000000000000000000000000000000000000000000000000000000000000000_U256,
shift: 0x0100_U256,
expected: 0xffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff_U256,
},
TestCase {
value: 0x8000000000000000000000000000000000000000000000000000000000000000_U256,
shift: 0x0101_U256,
expected: 0xffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff_U256,
},
TestCase {
value: 0xffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff_U256,
shift: 0x00_U256,
expected: 0xffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff_U256,
},
TestCase {
value: 0xffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff_U256,
shift: 0x01_U256,
expected: 0xffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff_U256,
},
TestCase {
value: 0xffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff_U256,
shift: 0xff_U256,
expected: 0xffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff_U256,
},
TestCase {
value: 0xffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff_U256,
shift: 0x0100_U256,
expected: 0xffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff_U256,
},
TestCase {
value: 0x0000000000000000000000000000000000000000000000000000000000000000_U256,
shift: 0x01_U256,
expected: 0x0000000000000000000000000000000000000000000000000000000000000000_U256,
},
TestCase {
value: 0x4000000000000000000000000000000000000000000000000000000000000000_U256,
shift: 0xfe_U256,
expected: 0x0000000000000000000000000000000000000000000000000000000000000001_U256,
},
TestCase {
value: 0x7fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff_U256,
shift: 0xf8_U256,
expected: 0x000000000000000000000000000000000000000000000000000000000000007f_U256,
},
TestCase {
value: 0x7fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff_U256,
shift: 0xfe_U256,
expected: 0x0000000000000000000000000000000000000000000000000000000000000001_U256,
},
TestCase {
value: 0x7fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff_U256,
shift: 0xff_U256,
expected: 0x0000000000000000000000000000000000000000000000000000000000000000_U256,
},
TestCase {
value: 0x7fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff_U256,
shift: 0x0100_U256,
expected: 0x0000000000000000000000000000000000000000000000000000000000000000_U256,
},
];
}

for test in test_cases {
host.clear();
push!(interpreter, test.value);
push!(interpreter, test.shift);
sar::<DummyHost, LatestSpec>(&mut interpreter, &mut host);
pop!(interpreter, res);
assert_eq!(res, test.expected);
}
}
}

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