vm: implement preimage reporting

packages/vm/src/runTx.ts

@@ -121,6 +121,10 @@ export async function runTx(this: VM, opts: RunTxOpts): Promise<RunTxResult> {
     this.evm.journal.startReportingAccessList()
   }
 
+  if (opts.reportPreimages === true) {
+    this.evm.journal.startReportingPreimages()
+  }
+
   await this.evm.journal.checkpoint()
   if (this.DEBUG) {
     debug('-'.repeat(100))
@@ -614,6 +618,10 @@ async function _runTx(this: VM, opts: RunTxOpts): Promise<RunTxResult> {
     results.accessList = accessList
   }
 
+  if (opts.reportPreimages === true && this.evm.journal.preimages !== undefined) {
+    results.preimages = this.evm.journal.preimages
+  }
+
   await this.evm.journal.cleanup()
   state.originalStorageCache.clear()
 

packages/vm/src/types.ts

@@ -357,6 +357,12 @@ export interface RunTxOpts {
    */
   reportAccessList?: boolean
 
+  /**
+   * If true, adds a hashedKey -> preimages mapping of all touched accounts
+   * to the `RunTxResult` returned.
+   */
+  reportPreimages?: boolean
+
   /**
    * To obtain an accurate tx receipt input the block gas used up until this tx.
    */
@@ -399,6 +405,11 @@ export interface RunTxResult extends EVMResult {
    */
   accessList?: AccessList
 
+  /**
+   * Preimages mapping of the touched accounts from the tx (see `reportPreimages` option)
+   */
+  preimages?: Map<string, Uint8Array>
+
   /**
    * The value that accrues to the miner by this transaction
    */