core/vm: improve jumpdest lookup

core/vm/contract.go

@@ -92,25 +92,28 @@ func (c *Contract) validJumpdest(dest *big.Int) bool {
  if OpCode(c.Code[udest]) != JUMPDEST {
  return false
  }
- // Do we have a contract hash already?
+ // Do we have it locally already?
+ if c.analysis != nil {
+ return c.analysis.codeSegment(udest)
+ }
+ // If we have the code hash (but no analysis), we should look into the
+ // parent analysis map and see if the analysis has been made previously
  if c.CodeHash != (common.Hash{}) {
- // Does parent context have the analysis?
  analysis, exist := c.jumpdests[c.CodeHash]
  if !exist {
  // Do the analysis and save in parent context
- // We do not need to store it in c.analysis
  analysis = codeBitmap(c.Code)
  c.jumpdests[c.CodeHash] = analysis
  }
+ // Also stash it in current contract for faster access
+ c.analysis = analysis
  return analysis.codeSegment(udest)
  }
  // We don't have the code hash, most likely a piece of initcode not already
  // in state trie. In that case, we do an analysis, and save it locally, so
  // we don't have to recalculate it for every JUMP instruction in the execution
  // However, we don't save it within the parent context
- if c.analysis == nil {
- c.analysis = codeBitmap(c.Code)
- }
+ c.analysis = codeBitmap(c.Code)
  return c.analysis.codeSegment(udest)
 }