From 3ebcf92b423e67b58a72a3fc126449e4e97bc4c8 Mon Sep 17 00:00:00 2001
From: dm4 <sunrisedm4@gmail.com>
Date: Fri, 6 Apr 2018 18:43:36 +0800
Subject: [PATCH] cmd/evm: print vm output when debug flag is on (#16326)

---
 cmd/evm/runner.go | 5 ++---
 core/vm/logger.go | 7 +++++++
 2 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/cmd/evm/runner.go b/cmd/evm/runner.go
index 8a7399840c..c13e9fb335 100644
--- a/cmd/evm/runner.go
+++ b/cmd/evm/runner.go
@@ -76,6 +76,7 @@ func runCmd(ctx *cli.Context) error {
 	logconfig := &vm.LogConfig{
 		DisableMemory: ctx.GlobalBool(DisableMemoryFlag.Name),
 		DisableStack:  ctx.GlobalBool(DisableStackFlag.Name),
+		Debug:         ctx.GlobalBool(DebugFlag.Name),
 	}
 
 	var (
@@ -234,9 +235,7 @@ Gas used:           %d
 
 `, execTime, mem.HeapObjects, mem.Alloc, mem.TotalAlloc, mem.NumGC, initialGas-leftOverGas)
 	}
-	if tracer != nil {
-		tracer.CaptureEnd(ret, initialGas-leftOverGas, execTime, err)
-	} else {
+	if tracer == nil {
 		fmt.Printf("0x%x\n", ret)
 		if err != nil {
 			fmt.Printf(" error: %v\n", err)
diff --git a/core/vm/logger.go b/core/vm/logger.go
index 4c820d8b53..dde1903bf2 100644
--- a/core/vm/logger.go
+++ b/core/vm/logger.go
@@ -45,6 +45,7 @@ type LogConfig struct {
 	DisableMemory  bool // disable memory capture
 	DisableStack   bool // disable stack capture
 	DisableStorage bool // disable storage capture
+	Debug          bool // print output during capture end
 	Limit          int  // maximum length of output, but zero means unlimited
 }
 
@@ -184,6 +185,12 @@ func (l *StructLogger) CaptureFault(env *EVM, pc uint64, op OpCode, gas, cost ui
 func (l *StructLogger) CaptureEnd(output []byte, gasUsed uint64, t time.Duration, err error) error {
 	l.output = output
 	l.err = err
+	if l.cfg.Debug {
+		fmt.Printf("0x%x\n", output)
+		if err != nil {
+			fmt.Printf(" error: %v\n", err)
+		}
+	}
 	return nil
 }