dev: optimize FromBytes (#907)

* dev: optimize FromBytes * use from_be_bytes_partial if input type isnt known" * fix: p256 verify output is a 32-bytes array * fix test p256 verify staticcall
kkrt-labs · Sep 5, 2024 · 37929a8 · 37929a8
1 parent 5132b8c
commit 37929a8
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Showing 5 changed files with 292 additions and 69 deletions.
diff --git a/crates/evm/src/precompiles/p256verify.cairo b/crates/evm/src/precompiles/p256verify.cairo
@@ -9,6 +9,43 @@ use utils::helpers::{U256Trait, ToBytes, FromBytes};
 
 const P256VERIFY_PRECOMPILE_GAS_COST: u128 = 3450;
 
+const ONE_32_BYTES: [
+    u8
+    ; 32] = [
+    0x00,
+    0x00,
+    0x00,
+    0x00,
+    0x00,
+    0x00,
+    0x00,
+    0x00,
+    0x00,
+    0x00,
+    0x00,
+    0x00,
+    0x00,
+    0x00,
+    0x00,
+    0x00,
+    0x00,
+    0x00,
+    0x00,
+    0x00,
+    0x00,
+    0x00,
+    0x00,
+    0x00,
+    0x00,
+    0x00,
+    0x00,
+    0x00,
+    0x00,
+    0x00,
+    0x00,
+    0x01
+];
+
 impl P256Verify of Precompile {
     #[inline(always)]
     fn address() -> EthAddress {
@@ -62,7 +99,7 @@ impl P256Verify of Precompile {
             return Result::Ok((gas, [].span()));
         }
 
-        return Result::Ok((gas, [1].span()));
+        return Result::Ok((gas, ONE_32_BYTES.span()));
     }
 }
 
@@ -105,7 +142,7 @@ mod tests {
 
         let (gas, result) = P256Verify::exec(calldata.span()).unwrap();
 
-        let result: u256 = result.from_be_bytes().unwrap();
+        let result: u256 = result.from_be_bytes().expect('p256verify_precompile_test');
         assert_eq!(result, 0x01);
         assert_eq!(gas, 3450);
     }
@@ -137,7 +174,7 @@ mod tests {
             .memory
             .store(0x7618b065f9832de4ca6ca971a7a1adc826d0f7c00181a5fb2ddf79ae00b4e10e, 0x80); // y
 
-        vm.stack.push(0x01).unwrap(); // retSize
+        vm.stack.push(0x20).unwrap(); // retSize
         vm.stack.push(0xa0).unwrap(); // retOffset
         vm.stack.push(0xa0).unwrap(); // argsSize
         vm.stack.push(0x0).unwrap(); // argsOffset
@@ -148,9 +185,9 @@ mod tests {
         vm.exec_staticcall().unwrap();
 
         let mut result = Default::default();
-        vm.memory.load_n(0x1, ref result, 0xa0);
+        vm.memory.load_n(0x20, ref result, 0xa0);
 
-        assert_eq!(result, array![0x01]);
+        assert_eq!(result.span(), super::ONE_32_BYTES.span());
     }
 
     #[test]

diff --git a/crates/utils/Scarb.toml b/crates/utils/Scarb.toml
@@ -9,6 +9,10 @@ edition = "2023_10"
 evm = { path = "../evm" }
 alexandria_data_structures = { path = "../alexandria_data_structures" }
 
+# For profiling
+[cairo]
+unstable-add-statements-functions-debug-info = true
+
 [tool]
 fmt.workspace = true
 

diff --git a/crates/utils/src/crypto/modexp/mpnat.cairo b/crates/utils/src/crypto/modexp/mpnat.cairo
@@ -70,7 +70,7 @@ pub impl MPNatTraitImpl of MPNatTrait {
             buf.copy_from_bytes_le((WORD_BYTES - r), bytes.slice(0, r)).unwrap();
 
             // safe unwrap, since we know that bytes won't overflow
-            let word = buf.to_le_bytes().from_be_bytes().unwrap();
+            let word = buf.to_le_bytes().from_be_bytes().expect('mpnat_from_big_endian_word');
             digits.set(i, word);
 
             if i == 0 {
@@ -88,7 +88,7 @@ pub impl MPNatTraitImpl of MPNatTrait {
             buf.copy_from_bytes_le(0, bytes.slice(j, next_j - j)).unwrap();
 
             // safe unwrap, since we know that bytes won't overflow
-            let word: u64 = buf.to_le_bytes().from_be_bytes().unwrap();
+            let word: u64 = buf.to_le_bytes().from_be_bytes().expect('mpnat_from_big_endian_word');
             digits.set(i, word);
 
             if i == 0 {
@@ -369,7 +369,7 @@ pub impl MPNatTraitImpl of MPNatTrait {
         }
 
         if exp.len() <= (ByteSize::<usize>::byte_size()) {
-            let exp_as_number: usize = exp.from_le_bytes().unwrap();
+            let exp_as_number: usize = exp.from_le_bytes_partial().expect('modpow_exp_as_number');
 
             match self.digits.len().checked_mul(exp_as_number) {
                 Option::Some(max_output_digits) => {
@@ -714,7 +714,7 @@ mod tests {
 
             i += 1;
         };
-        result.from_le_bytes().unwrap()
+        result.from_le_bytes_partial().expect('mpnat_to_u128')
     }
 
     fn check_modpow_even(base: u128, exp: u128, modulus: u128, expected: u128) {