tracing opcode return value

nimbus/tracer.nim

@@ -39,6 +39,11 @@ proc traceTransaction*(db: BaseChainDB, header: BlockHeader,
   result = vmState.getTracingResult()
   result["gas"] = %gasUsed
 
+  const returnValue = "returnValue"
+  let j = result["structLogs"].elems[^1]
+  if j.hasKey(returnValue):
+    result[returnValue] = j[returnValue]
+
   # now we dump captured state db
   if TracerFlags.DisableState notin tracerFlags:
     var n = newJObject()

nimbus/vm/computation.nim

@@ -59,6 +59,7 @@ func output*(c: BaseComputation): seq[byte] =
 
 func `output=`*(c: var BaseComputation, value: openarray[byte]) =
   c.rawOutput = @value
+  c.lastOpCodeHasRetVal = true
 
 proc outputHex*(c: BaseComputation): string =
   if c.shouldEraseReturnData:

nimbus/vm/interpreter_dispatch.nim

@@ -194,6 +194,7 @@ proc opTableToCaseStmt(opTable: array[Op, NimNode], computation: NimNode): NimNo
             if `computation`.tracingEnabled:
               `computation`.traceOpCodeStarted($`asOp`)
             `computation`.gasMeter.consumeGas(`computation`.gasCosts[`asOp`].cost, reason = $`asOp`)
+            `computation`.lastOpCodeHasRetVal = false
             `opImpl`(`computation`)
             if `computation`.tracingEnabled:
               `computation`.traceOpCodeEnded()
@@ -202,6 +203,7 @@ proc opTableToCaseStmt(opTable: array[Op, NimNode], computation: NimNode): NimNo
           quote do:
             if `computation`.tracingEnabled:
               `computation`.traceOpCodeStarted($`asOp`)
+            `computation`.lastOpCodeHasRetVal = false
             `opImpl`(`computation`)
             if `computation`.tracingEnabled:
               `computation`.traceOpCodeEnded()

nimbus/vm/transaction_tracer.nim

@@ -1,10 +1,7 @@
 import
-  json, strutils,
-  eth_common, stint, byteutils,
-  ../vm_types, memory, stack,
-  ../db/[db_chain, state_db],
-  eth_trie/hexary, ./message,
-  ranges/typedranges
+  json, strutils, nimcrypto, eth_common, stint,
+  ../vm_types, memory, stack, ../db/[db_chain, state_db],
+  eth_trie/hexary, ./message, ranges/typedranges
 
 proc initTracer*(tracer: var TransactionTracer, flags: set[TracerFlags] = {}) =
   tracer.trace = newJObject()
@@ -60,6 +57,9 @@ proc traceOpCodeEnded*(tracer: var TransactionTracer, c: BaseComputation) =
 
   j["gasCost"] = %(tracer.gasRemaining - c.gasMeter.gasRemaining)
 
+  if c.lastOpCodeHasRetVal:
+    j["returnValue"] = %("0x" & toHex(c.rawOutput, true))
+
 proc traceError*(tracer: var TransactionTracer, c: BaseComputation) =
   let j = tracer.trace["structLogs"].elems[^1]
 

nimbus/vm_types.nim

@@ -59,6 +59,7 @@ type
     opcodes*:               Table[Op, proc(computation: var BaseComputation){.nimcall.}]
     gasCosts*:              GasCosts # TODO - will be hidden at a lower layer
     opCodeExec*:            OpcodeExecutor
+    lastOpCodeHasRetVal*:   bool
 
   Error* = ref object
     info*:                  string