feat(acir-simulator): advanced debug formatting for noir + acir simulator

yarn-project/acir-simulator/src/client/debug.ts

@@ -0,0 +1,74 @@
+import { ACVMField } from '../acvm/index.js';
+
+/**
+ * Convert an array of ACVMFields to a string.
+ *
+ * @param msg - array of ACVMFields where each represents a single ascii character
+ * @returns string representation of the message
+ */
+function acvmFieldMessageToString(msg: ACVMField[]): string {
+  let msgStr = '';
+  for (const msgChar of msg) {
+    const asciiCode = Number(msgChar);
+    const asciiChar = String.fromCharCode(asciiCode);
+    msgStr = msgStr.concat(asciiChar);
+  }
+  // cut off string in case of preemptive null termination
+  const nullCharIndex = msgStr.indexOf('\\0');
+  if (nullCharIndex >= 0) {
+    msgStr = msgStr.substring(0, nullCharIndex);
+  }
+  return msgStr.replaceAll('\\n', '\n').replaceAll('\\t', '\t');
+}
+
+/**
+ * Format a debug string for Noir filling in `'{0}'` entries with their
+ * corresponding values from the args array.
+ *
+ * @param formatStr - str of form `'this is a string with some entries like {0} and {1}'`
+ * @param args - array of fields to fill in the string format entries with
+ * @returns formatted string
+ */
+function applyStringFormatting(formatStr: string, args: ACVMField[]): string {
+  const matches = formatStr.match(/{\d+}/g);
+  if (matches == null) {
+    return formatStr;
+  }
+  // Get the numeric values within the curly braces, convert them to numbers,
+  // and find the maximum value.
+  const maxIndex = Math.max(...matches.map(match => Number(match.slice(1, -1))));
+  const argsPadded = args.concat(Array.from({ length: Math.max(0, maxIndex - args.length) }, () => '0xBAD'));
+
+  return formatStr.replace(/{(\d+)}/g, function (match, index) {
+    return typeof args[index] != 'undefined' ? argsPadded[index] : match;
+  });
+}
+
+/**
+ * Convert an array of ACVMFields from ACVM to a formatted string.
+ *
+ * @param fields - either a single field to be printed, or a string to be formatted.
+ * When it is a string to be formatted:
+ * The last entry in `fields` is `numArgs` (the number of formatting
+ * args). The `formatArgs` occupy the end of the `fields` array,
+ * excluding that last entry (`numArgs`). The message string `msg`
+ * takes up the remaining entries at the start of the `fields` array.
+ *
+ * @returns formatted string
+ */
+export function fieldsToFormattedStr(fields: ACVMField[]): string {
+  if (fields.length === 1) {
+    return `${fields[0]}`;
+  } else {
+    const numArgs = Number(fields[fields.length - 1]);
+    const msgLen = fields.length - 1 - numArgs;
+
+    const msgFields = fields.slice(0, msgLen);
+    const formatArgs = fields.slice(msgLen, fields.length - 1);
+
+    const msg = acvmFieldMessageToString(msgFields);
+    const formattedMsg = applyStringFormatting(msg, formatArgs);
+
+    return formattedMsg;
+  }
+}

yarn-project/acir-simulator/src/client/private_execution.ts

@@ -26,6 +26,7 @@ import {
   toAcvmEnqueuePublicFunctionResult,
 } from '../acvm/index.js';
 import { sizeOfType } from '../index.js';
+import { fieldsToFormattedStr } from './debug.js';
 import { ClientTxExecutionContext } from './client_execution_context.js';
 import { Tuple, assertLength } from '@aztec/foundation/serialize';
 
@@ -173,9 +174,8 @@ export class PrivateFunctionExecution {
       },
       getL1ToL2Message: ([msgKey]: ACVMField[]) => this.context.getL1ToL2Message(fromACVMField(msgKey)),
 
-      debugLog: ([data]: ACVMField[]) => {
-        // eslint-disable-next-line
-        console.log(data);
+      debugLog: (fields: ACVMField[]) => {
+        this.log(fieldsToFormattedStr(fields));
         return Promise.resolve([ZERO_ACVM_FIELD]);
       },
       enqueuePublicFunctionCall: async ([acvmContractAddress, acvmFunctionSelector, ...acvmArgs]) => {

yarn-project/acir-simulator/src/client/unconstrained_execution.ts

@@ -8,6 +8,7 @@ import { ClientTxExecutionContext } from './client_execution_context.js';
 import { select_return_flattened as selectReturnFlattened } from '@noir-lang/noir_util_wasm';
 import { AztecAddress } from '@aztec/foundation/aztec-address';
 import { Fr } from '@aztec/foundation/fields';
+import { fieldsToFormattedStr } from './debug.js';
 
 const notAvailable = () => {
   return Promise.reject(new Error(`Not available for unconstrained function execution`));
@@ -55,9 +56,8 @@ export class UnconstrainedFunctionExecution {
           frToNumber(fromACVMField(acvmLimit)),
           frToNumber(fromACVMField(acvmOffset)),
         ),
-      debugLog: ([data]: ACVMField[]) => {
-        // eslint-disable-next-line
-        console.log(data);
+      debugLog: (fields: ACVMField[]) => {
+        this.log(fieldsToFormattedStr(fields));
         return Promise.resolve([ZERO_ACVM_FIELD]);
       },
       getL1ToL2Message: ([msgKey]: ACVMField[]) => this.context.getL1ToL2Message(fromACVMField(msgKey)),

yarn-project/noir-contracts/src/contracts/noir-aztec3/src/oracle/debug_log.nr

@@ -1,9 +1,32 @@
-
 // Utility function to console.log data in the acir simulator
+// WARNING: sometimes when using debug logs the ACVM errors with: `thrown: "solver opcode resolution error: cannot solve opcode: expression has too many unknowns x155"`
 
 #[oracle(debugLog)]
-fn debug_log_oracle(_msg: Field) -> Field {}
+fn debug_log_oracle<T, N>(_msg: T, _num_args: Field) -> Field {}
+#[oracle(debugLog)]
+fn debug_log_format_oracle<T, N>(_msg: T, _args: [Field; N], _num_args: Field) -> Field {}
+#[oracle(debugLog)]
+fn debug_log_field_oracle(_field: Field) -> Field {}
+
+/// NOTE: call this with a str<N> msg of length > 1
+/// Example:
+/// `debug_log("blah blah this is a debug string");`
+unconstrained fn debug_log<T>(msg: T) {
+    constrain debug_log_oracle(msg, 0) == 0;
+}
+
+/// NOTE: call this with a str<N> msg of form
+/// "some string with {0} and {1} ... {N}"
+/// and an array of N field which will be formatted
+/// into the string in the simulator.
+/// Example:
+/// `debug_log_format("get_2(slot:{0}) =>\n\t0:{1}\n\t1:{2}", [storage_slot, notes.0.value, notes.1.value]);`
+unconstrained fn debug_log_format<T, N>(msg: T, args: [Field; N]) {
+    constrain debug_log_format_oracle(msg, args, args.len()) == 0;
+}
 
-unconstrained fn debug_log(msg: Field) -> Field {
-    debug_log_oracle(msg)
-}
+/// Example:
+/// `debug_log_field(my_field);`
+unconstrained fn debug_log_field(field: Field) {
+    constrain debug_log_field_oracle(field) == 0;
+}

yarn-project/noir-contracts/src/contracts/noir-aztec3/src/state_vars/set.nr

@@ -83,6 +83,7 @@ impl Set {
         constrain note_getter_data.1.root == inputs.old_private_data_tree_root;
 
         let notes = (note_getter_data.0.note, note_getter_data.1.note);
+
         (context, notes)
     }