fix step over back, step over forward

src/trace/traceStepManager.js

@@ -8,7 +8,7 @@ function TraceStepManager (_traceAnalyser) {
 
 TraceStepManager.prototype.isCallInstruction = function (index) {
   var state = this.traceAnalyser.trace[index]
-  return traceHelper.isCallInstruction(state)
+  return traceHelper.isCallInstruction(state) && !traceHelper.isCallToPrecompiledContract(index, this.traceAnalyser.trace)
 }
 
 TraceStepManager.prototype.isReturnInstruction = function (index) {
@@ -17,8 +17,9 @@ TraceStepManager.prototype.isReturnInstruction = function (index) {
 }
 
 TraceStepManager.prototype.findStepOverBack = function (currentStep) {
-  if (this.isReturnInstruction(currentStep - 1)) {
-    return this.traceAnalyser.traceCache.calls[currentStep].call - 1
+  if (this.isReturnInstruction(currentStep)) {
+    var call = util.findCall(currentStep, this.traceAnalyser.traceCache.callsTree.call)
+    return call.start > 0 ? call.start - 1 : 0
   } else {
     return currentStep > 0 ? currentStep - 1 : 0
   }
@@ -26,7 +27,8 @@ TraceStepManager.prototype.findStepOverBack = function (currentStep) {
 
 TraceStepManager.prototype.findStepOverForward = function (currentStep) {
   if (this.isCallInstruction(currentStep)) {
-    return this.traceAnalyser.traceCache.calls[currentStep + 1].return
+    var call = util.findCall(currentStep + 1, this.traceAnalyser.traceCache.callsTree.call)
+    return call.return + 1 < this.traceAnalyser.trace.length ? call.return + 1 : this.traceAnalyser.trace.length - 1
   } else {
     return this.traceAnalyser.trace.length >= currentStep + 1 ? currentStep + 1 : currentStep
   }

test-browser/vmdebugger.js

@@ -130,15 +130,19 @@ function stepping (browser) {
     .click('#intoforward')
     .click('#overforward')
     .assertCurrentSelectedItem('007 MLOAD')
-    .click('#overback')
-    .click('#overback')
-    .click('#overback')
-    .click('#overback')
-    .click('#overback')
+    .click('#intoback')
+    .click('#intoback')
+    .click('#intoback')
+    .click('#intoback')
+    .click('#intoback')
     .click('#overforward')
     .assertCurrentSelectedItem('182 PUSH1 01')
     .click('#overforward')
     .assertCurrentSelectedItem('184 PUSH1 00')
+    .click('#intoback')
+    .click('#intoback')
+    .click('#overback')
+    .assertCurrentSelectedItem('181 CREATE')
   return browser
 }