eth/tracers: native prestate tracer (ethereum#24268)

* eth/tracers: add initial native prestate tracer

* fix balance hex

* handle prestate for tx from and to

* drop created contract from prestate

* fix sender balance

* use switch instead

Co-authored-by: Martin Holst Swende <martin@swende.se>

* minor fix

* lookup create2 account

* mv code around a bit

* check stackLen for create2

* fix transfer tx for js prestate tracer

* fix create2 addr

* track extcodehash in js prestate tracer

Co-authored-by: Martin Holst Swende <martin@swende.se>

eth/tracers/js/internal/tracers/prestate_tracer.js

@@ -47,6 +47,13 @@
 	// result is invoked when all the opcodes have been iterated over and returns
 	// the final result of the tracing.
 	result: function(ctx, db) {
+		if (this.prestate === null) {
+			this.prestate = {};
+			// If tx is transfer-only, the recipient account
+			// hasn't been populated.
+			this.lookupAccount(ctx.to, db);
+		}
+
 		// At this point, we need to deduct the 'value' from the
 		// outer transaction, and move it back to the origin
 		this.lookupAccount(ctx.from, db);
@@ -79,7 +86,7 @@
 		}
 		// Whenever new state is accessed, add it to the prestate
 		switch (log.op.toString()) {
-			case "EXTCODECOPY": case "EXTCODESIZE": case "BALANCE":
+			case "EXTCODECOPY": case "EXTCODESIZE": case "EXTCODEHASH": case "BALANCE":
 				this.lookupAccount(toAddress(log.stack.peek(0).toString(16)), db);
 				break;
 			case "CREATE":

eth/tracers/native/call.go

@@ -59,8 +59,7 @@ type callTracer struct {
 func newCallTracer() tracers.Tracer {
 	// First callframe contains tx context info
 	// and is populated on start and end.
-	t := &callTracer{callstack: make([]callFrame, 1)}
-	return t
+	return &callTracer{callstack: make([]callFrame, 1)}
 }
 
 // CaptureStart implements the EVMLogger interface to initialize the tracing operation.