eth, eth/tracers: expose gas used in tx to js tracer

eth/api_tracer.go

@@ -794,7 +794,7 @@ func (api *PrivateDebugAPI) traceTx(ctx context.Context, message core.Message, v
  }
  }
  // Constuct the JavaScript tracer to execute with
- if tracer, err = tracers.New(*config.Tracer); err != nil {
+ if tracer, err = tracers.New(*config.Tracer, txContext); err != nil {
  return nil, err
  }
  // Handle timeouts and RPC cancellations

eth/tracers/internal/tracers/prestate_tracer.js

@@ -55,7 +55,7 @@
  var toBal = bigInt(this.prestate[toHex(ctx.to)].balance.slice(2), 16);
 
  this.prestate[toHex(ctx.to)].balance = '0x'+toBal.subtract(ctx.value).toString(16);
- this.prestate[toHex(ctx.from)].balance = '0x'+fromBal.add(ctx.value).toString(16);
+ this.prestate[toHex(ctx.from)].balance = '0x'+fromBal.add(ctx.value).add((ctx.gasUsed + ctx.intrinsicGas) * ctx.gasPrice).toString(16);
 
  // Decrement the caller's nonce, and remove empty create targets
  this.prestate[toHex(ctx.from)].nonce--;

eth/tracers/tracer.go

@@ -27,10 +27,11 @@ import (
 
  "github.com/ethereum/go-ethereum/common"
  "github.com/ethereum/go-ethereum/common/hexutil"
+ "github.com/ethereum/go-ethereum/core"
  "github.com/ethereum/go-ethereum/core/vm"
  "github.com/ethereum/go-ethereum/crypto"
  "github.com/ethereum/go-ethereum/log"
- "gopkg.in/olebedev/go-duktape.v3"
+ duktape "gopkg.in/olebedev/go-duktape.v3"
 )
 
 // bigIntegerJS is the minified version of https:/peterolson/BigInteger.js.
@@ -316,7 +317,7 @@ type Tracer struct {
 // New instantiates a new tracer instance. code specifies a Javascript snippet,
 // which must evaluate to an expression returning an object with 'step', 'fault'
 // and 'result' functions.
-func New(code string) (*Tracer, error) {
+func New(code string, txCtx vm.TxContext) (*Tracer, error) {
  // Resolve any tracers by name and assemble the tracer object
  if tracer, ok := tracer(code); ok {
  code = tracer
@@ -335,6 +336,8 @@ func New(code string) (*Tracer, error) {
  depthValue: new(uint),
  refundValue: new(uint),
  }
+ tracer.ctx["gasPrice"] = txCtx.GasPrice
+
  // Set up builtins for this environment
  tracer.vm.PushGlobalGoFunction("toHex", func(ctx *duktape.Context) int {
  ctx.PushString(hexutil.Encode(popSlice(ctx)))
@@ -546,6 +549,18 @@ func (jst *Tracer) CaptureState(env *vm.EVM, pc uint64, op vm.OpCode, gas, cost
  // Initialize the context if it wasn't done yet
  if !jst.inited {
  jst.ctx["block"] = env.Context.BlockNumber.Uint64()
+ // Compute intrinsic gas
+ isHomestead := env.ChainConfig().IsHomestead(env.Context.BlockNumber)
+ isIstanbul := env.ChainConfig().IsIstanbul(env.Context.BlockNumber)
+ var input []byte
+ if data, ok := jst.ctx["input"].([]byte); ok {
+ input = data
+ }
+ intrinsicGas, err := core.IntrinsicGas(input, jst.ctx["type"] == "CREATE", isHomestead, isIstanbul)
+ if err != nil {
+ return err
+ }
+ jst.ctx["intrinsicGas"] = intrinsicGas
  jst.inited = true
  }
  // If tracing was interrupted, set the error and stop
@@ -597,8 +612,8 @@ func (jst *Tracer) CaptureFault(env *vm.EVM, pc uint64, op vm.OpCode, gas, cost
 // CaptureEnd is called after the call finishes to finalize the tracing.
 func (jst *Tracer) CaptureEnd(output []byte, gasUsed uint64, t time.Duration, err error) error {
  jst.ctx["output"] = output
- jst.ctx["gasUsed"] = gasUsed
  jst.ctx["time"] = t.String()
+ jst.ctx["gasUsed"] = gasUsed
 
  if err != nil {
  jst.ctx["error"] = err.Error()