Reimplement snarky backend with TS bigints

CHANGELOG.md

@@ -25,6 +25,11 @@ This project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.htm
   - To recover existing verification keys and behavior, change the order of properties in your Struct definitions to be alphabetical
   - The `customObjectKeys` option is removed from `Struct`
 
+### Changed
+
+- Improve prover performance by ~25% https://github.com/o1-labs/o1js/pull/1092
+  - Change internal representation of field elements to be JS bigint instead of Uint8Array
+
 ## [0.13.0](https://github.com/o1-labs/o1js/compare/fbd4b2717...c2f392fe5)
 
 ### Breaking changes

src/build/buildExample.js

@@ -37,6 +37,7 @@ async function build(srcPath, isWeb = false) {
           makeNodeModulesExternal(),
           makeJsooExternal(),
         ],
+    dropLabels: ['CJS'],
   });
 
   let absPath = path.resolve('.', outfile);
@@ -110,7 +111,7 @@ function makeNodeModulesExternal() {
 }
 
 function makeJsooExternal() {
-  let isJsoo = /(bc.cjs|plonk_wasm.cjs|wrapper.js)$/;
+  let isJsoo = /(bc.cjs|plonk_wasm.cjs)$/;
   return {
     name: 'plugin-external',
     setup(build) {

src/build/buildWeb.js

@@ -90,6 +90,7 @@ async function buildWeb({ production }) {
     outfile: 'dist/web/index.js',
     resolveExtensions: ['.js', '.ts'],
     plugins: [wasmPlugin(), srcStringPlugin()],
+    dropLabels: ['CJS'],
     external: ['*.bc.js'],
     target,
     allowOverwrite: true,

src/examples/benchmarks/hash-witness.ts

@@ -1,7 +1,7 @@
 /**
  * benchmark witness generation for an all-mul circuit
  */
-import { Field, Provable, Poseidon } from 'snarkyjs';
+import { Field, Provable, Poseidon } from 'o1js';
 import { tic, toc } from './tic-toc.js';
 
 // parameters

src/examples/benchmarks/import.web.ts

@@ -1,5 +1,5 @@
 let start = performance.now();
-await import('snarkyjs');
+await import('o1js');
 let time = performance.now() - start;
 
 console.log(`import jsoo: ${time.toFixed(0)}ms`);

src/examples/benchmarks/mul-witness.ts

@@ -1,7 +1,7 @@
 /**
  * benchmark witness generation for an all-mul circuit
  */
-import { Field, Provable } from 'snarkyjs';
+import { Field, Provable } from 'o1js';
 import { tic, toc } from './tic-toc.js';
 
 // parameters

src/lib/field.ts

@@ -21,23 +21,20 @@ export {
   toConstantField,
 };
 
-type FieldConst = Uint8Array;
+type FieldConst = [0, bigint];
 
 function constToBigint(x: FieldConst): Fp {
-  return Fp.fromBytes([...x]);
+  return x[1];
 }
-function constFromBigint(x: Fp) {
-  return Uint8Array.from(Fp.toBytes(x));
+function constFromBigint(x: Fp): FieldConst {
+  return [0, x];
 }
 
 const FieldConst = {
   fromBigint: constFromBigint,
   toBigint: constToBigint,
   equal(x: FieldConst, y: FieldConst) {
-    for (let i = 0, n = Fp.sizeInBytes(); i < n; i++) {
-      if (x[i] !== y[i]) return false;
-    }
-    return true;
+    return x[1] === y[1];
   },
   [0]: constFromBigint(0n),
   [1]: constFromBigint(1n),
@@ -145,15 +142,16 @@ class Field {
       this.value = x.value;
       return;
     }
-    // FieldVar
     if (Array.isArray(x)) {
-      this.value = x;
-      return;
-    }
-    // FieldConst
-    if (x instanceof Uint8Array) {
-      this.value = FieldVar.constant(x);
-      return;
+      if (typeof x[1] === 'bigint') {
+        // FieldConst
+        this.value = FieldVar.constant(x as FieldConst);
+        return;
+      } else {
+        // FieldVar
+        this.value = x as FieldVar;
+        return;
+      }
     }
     // TODO this should handle common values efficiently by reading from a lookup table
     this.value = FieldVar.constant(Fp(x));
@@ -1269,12 +1267,14 @@ class Field {
 
 const FieldBinable = defineBinable({
   toBytes(t: Field) {
-    return [...toConstantField(t, 'toBytes').value[1]];
+    let t0 = toConstantField(t, 'toBytes').toBigInt();
+    return Fp.toBytes(t0);
   },
   readBytes(bytes, offset) {
     let uint8array = new Uint8Array(32);
     uint8array.set(bytes.slice(offset, offset + 32));
-    return [new Field(uint8array), offset + 32];
+    let x = Fp.fromBytes([...uint8array]);
+    return [new Field(x), offset + 32];
   },
 });
 

src/lib/scalar.ts

@@ -10,11 +10,14 @@ export { Scalar, ScalarConst, unshift, shift };
 export { constantScalarToBigint };
 
 type BoolVar = FieldVar;
-type ScalarConst = Uint8Array;
+type ScalarConst = [0, bigint];
 
 const ScalarConst = {
   fromBigint: constFromBigint,
   toBigint: constToBigint,
+  is(x: any): x is ScalarConst {
+    return Array.isArray(x) && x[0] === 0 && typeof x[1] === 'bigint';
+  },
 };
 
 let scalarShift = Fq(1n + 2n ** 255n);
@@ -44,9 +47,9 @@ class Scalar {
    *
    * If the input is too large, it is reduced modulo the scalar field size.
    */
-  static from(x: Scalar | Uint8Array | bigint | number | string) {
+  static from(x: Scalar | ScalarConst | bigint | number | string) {
     if (x instanceof Scalar) return x;
-    if (x instanceof Uint8Array) x = ScalarConst.toBigint(x);
+    if (ScalarConst.is(x)) x = constToBigint(x);
     let scalar = Fq(x);
     let bits = toBits(scalar);
     return new Scalar(bits, scalar);
@@ -348,10 +351,10 @@ function unshift(s: Fq): Fq {
 }
 
 function constToBigint(x: ScalarConst): Fq {
-  return Fq.fromBytes([...x]);
+  return x[1];
 }
-function constFromBigint(x: Fq) {
-  return Uint8Array.from(Fq.toBytes(x));
+function constFromBigint(x: Fq): ScalarConst {
+  return [0, x];
 }
 
 function constantScalarToBigint(s: Scalar, name: string) {

src/mina-signer/src/sign-zkapp-command.unit-test.ts

@@ -275,7 +275,7 @@ function fixVerificationKey(a: AccountUpdate) {
     let [, data, hash] = Pickles.dummyVerificationKey();
     a.body.update.verificationKey.value = {
       data,
-      hash: Field.fromBytes([...hash]),
+      hash: FieldConst.toBigint(hash),
     };
   } else {
     a.body.update.verificationKey.value = {