Fix lowest-hanging fruit in VM (#2382)

* replace set with bitseq for code validity test
* remove unusued code from CodeStream
* avoid unnecessary byte-by-byte copies

nimbus/db/ledger/accounts_ledger.nim

@@ -613,7 +613,7 @@ proc clearEmptyAccounts(ac: AccountsLedgerRef) =
  ac.ripemdSpecial = false
 
 proc persist*(ac: AccountsLedgerRef,
- clearEmptyAccount: bool = false) {.deprecated.} =
+ clearEmptyAccount: bool = false) =
  # make sure all savepoint already committed
  doAssert(ac.savePoint.parentSavepoint.isNil)
 

nimbus/evm/code_stream.nim

@@ -6,7 +6,7 @@
 # at your option. This file may not be copied, modified, or distributed except according to those terms.
 
 import
- chronicles, strformat, strutils, sequtils, parseutils, sets, macros,
+ chronicles, strformat, strutils, sequtils, parseutils,
  eth/common,
  ./interpreter/op_codes
 
@@ -17,20 +17,25 @@ type
  CodeStream* = ref object
  bytes*: seq[byte]
  depthProcessed: int
- invalidPositions: HashSet[int]
+ invalidPositions: seq[byte] # bit seq of invalid jump positions
  pc*: int
- cached: seq[(int, Op, string)]
 
 proc `$`*(b: byte): string =
  $(b.int)
 
+template bitpos(pos: int): (int, byte) =
+ (pos shr 3, 1'u8 shl (pos and 0x07))
+
 proc newCodeStream*(codeBytes: sink seq[byte]): CodeStream =
  new(result)
  result.bytes = system.move(codeBytes)
  result.pc = 0
- result.invalidPositions = HashSet[int]()
+ result.invalidPositions = newSeq[byte]((result.bytes.len + 7) div 8)
  result.depthProcessed = 0
- result.cached = @[]
+
+proc invalidPosition(c: CodeStream, pos: int): bool =
+ let (bpos, bbit) = bitpos(pos)
+ (c.invalidPositions[bpos] and bbit) > 0
 
 proc newCodeStream*(codeBytes: string): CodeStream =
  newCodeStream(codeBytes.mapIt(it.byte))
@@ -45,14 +50,15 @@ proc newCodeStreamFromUnescaped*(code: string): CodeStream =
  codeBytes.add(value.byte)
  newCodeStream(codeBytes)
 
-proc read*(c: var CodeStream, size: int): seq[byte] =
+template read*(c: CodeStream, size: int): openArray[byte] =
  # TODO: use openArray[bytes]
  if c.pc + size - 1 < c.bytes.len:
- result = c.bytes[c.pc .. c.pc + size - 1]
+ let pos = c.pc
  c.pc += size
+ c.bytes.toOpenArray(pos, pos + size - 1)
  else:
- result = @[]
  c.pc = c.bytes.len
+ c.bytes.toOpenArray(0, -1)
 
 proc readVmWord*(c: var CodeStream, n: int): UInt256 =
  ## Reads `n` bytes from the code stream and pads
@@ -72,11 +78,11 @@ proc next*(c: var CodeStream): Op =
  result = Op(c.bytes[c.pc])
  inc c.pc
  else:
- result = Stop
+ result = Op.Stop
 
 iterator items*(c: var CodeStream): Op =
  var nextOpcode = c.next()
- while nextOpcode != Op.STOP:
+ while nextOpcode != Op.Stop:
  yield nextOpcode
  nextOpcode = c.next()
 
@@ -85,76 +91,50 @@ proc `[]`*(c: CodeStream, offset: int): Op =
 
 proc peek*(c: var CodeStream): Op =
  if c.pc < c.bytes.len:
- result = Op(c.bytes[c.pc])
+ Op(c.bytes[c.pc])
  else:
- result = Stop
+ Op.Stop
 
 proc updatePc*(c: var CodeStream, value: int) =
  c.pc = min(value, len(c))
 
-when false:
- template seek*(cs: var CodeStream, pc: int, handler: untyped): untyped =
- var anchorPc = cs.pc
- cs.pc = pc
- try:
- var c {.inject.} = cs
- handler
- finally:
- cs.pc = anchorPc
-
 proc isValidOpcode*(c: CodeStream, position: int): bool =
  if position >= len(c):
- return false
- if position in c.invalidPositions:
- return false
- if position <= c.depthProcessed:
- return true
+ false
+ elif c.invalidPosition(position):
+ false
+ elif position <= c.depthProcessed:
+ true
  else:
  var i = c.depthProcessed
  while i <= position:
  var opcode = Op(c[i])
- if opcode >= Op.PUSH1 and opcode <= Op.PUSH32:
+ if opcode >= Op.Push1 and opcode <= Op.Push32:
  var leftBound = (i + 1)
  var rightBound = leftBound + (opcode.int - 95)
  for z in leftBound ..< rightBound:
- c.invalidPositions.incl(z)
+ let (bpos, bbit) = bitpos(z)
+ c.invalidPositions[bpos] = c.invalidPositions[bpos] or bbit
  i = rightBound
  else:
- c.depthProcessed = i
  i += 1
- if position in c.invalidPositions:
- return false
- else:
- return true
+ c.depthProcessed = i - 1
+
+ not c.invalidPosition(position)
 
-proc decompile*(original: var CodeStream): seq[(int, Op, string)] =
+proc decompile*(original: CodeStream): seq[(int, Op, string)] =
  # behave as https://etherscan.io/opcode-tool
- # TODO
- if original.cached.len > 0:
- return original.cached
- result = @[]
  var c = newCodeStream(original.bytes)
  while true:
  var op = c.next
  if op >= Push1 and op <= Push32:
- let bytes = c.read(op.int - 95)
- result.add((c.pc - 1, op, "0x" & bytes.mapIt($(it.BiggestInt.toHex(2))).join("")))
+ result.add(
+  (c.pc - 1, op, "0x" & c.read(op.int - 95).mapIt($(it.BiggestInt.toHex(2))).join("")))
  elif op != Op.Stop:
  result.add((c.pc - 1, op, ""))
  else:
  result.add((-1, Op.Stop, ""))
  break
- original.cached = result
-
-proc displayDecompiled*(c: CodeStream) =
- var copy = c
- let opcodes = copy.decompile()
- for op in opcodes:
- echo op[0], " ", op[1], " ", op[2]
-
-proc hasSStore*(c: var CodeStream): bool =
- let opcodes = c.decompile()
- result = opcodes.anyIt(it[1] == Sstore)
 
 proc atEnd*(c: CodeStream): bool =
- result = c.pc >= c.bytes.len
+ c.pc >= c.bytes.len

nimbus/evm/interpreter/op_handlers/oph_call.nim

@@ -276,7 +276,7 @@ proc callOp(k: var VmCtx): EvmResultVoid =
  contractAddress: p.contractAddress,
  codeAddress: p.codeAddress,
  value: p.value,
- data: cpt.memory.read(p.memInPos, p.memInLen),
+ data: @(cpt.memory.read(p.memInPos, p.memInLen)),
  flags: p.flags))
  ok()
 
@@ -353,7 +353,7 @@ proc callCodeOp(k: var VmCtx): EvmResultVoid =
  contractAddress: p.contractAddress,
  codeAddress: p.codeAddress,
  value: p.value,
- data: cpt.memory.read(p.memInPos, p.memInLen),
+ data: @(cpt.memory.read(p.memInPos, p.memInLen)),
  flags: p.flags))
  ok()
 
@@ -425,7 +425,7 @@ proc delegateCallOp(k: var VmCtx): EvmResultVoid =
  contractAddress: p.contractAddress,
  codeAddress: p.codeAddress,
  value: p.value,
- data: cpt.memory.read(p.memInPos, p.memInLen),
+ data: @(cpt.memory.read(p.memInPos, p.memInLen)),
  flags: p.flags))
  ok()
 
@@ -498,7 +498,7 @@ proc staticCallOp(k: var VmCtx): EvmResultVoid =
  contractAddress: p.contractAddress,
  codeAddress: p.codeAddress,
  value: p.value,
- data: cpt.memory.read(p.memInPos, p.memInLen),
+ data: @(cpt.memory.read(p.memInPos, p.memInLen)),
  flags: p.flags))
  ok()
 

nimbus/evm/interpreter/op_handlers/oph_create.nim

@@ -156,7 +156,7 @@ proc createOp(k: var VmCtx): EvmResultVoid =
  gas: createMsgGas,
  sender: cpt.msg.contractAddress,
  value: endowment,
- data: cpt.memory.read(memPos, memLen)))
+ data: @(cpt.memory.read(memPos, memLen))))
  ok()
 
 # ---------------------
@@ -240,7 +240,7 @@ proc create2Op(k: var VmCtx): EvmResultVoid =
  gas: createMsgGas,
  sender: cpt.msg.contractAddress,
  value: endowment,
- data: cpt.memory.read(memPos, memLen)))
+ data: @(cpt.memory.read(memPos, memLen))))
  ok()
 
 # ------------------------------------------------------------------------------

nimbus/evm/interpreter/op_handlers/oph_log.nim

@@ -15,6 +15,7 @@
 {.push raises: [].}
 
 import
+ stew/assign2,
  ../../../constants,
  ../../evm_errors,
  ../../computation,
@@ -77,7 +78,7 @@ proc logImpl(c: Computation, opcode: Op, topicCount: int): EvmResultVoid =
  let topic = ? c.stack.popTopic()
  log.topics.add topic
 
- log.data = c.memory.read(memPos, len)
+ assign(log.data, c.memory.read(memPos, len))
  log.address = c.msg.contractAddress
  c.addLogEntry(log)
 

nimbus/evm/interpreter/op_handlers/oph_memory.nim

@@ -112,7 +112,7 @@ func jumpImpl(c: Computation; jumpTarget: UInt256): EvmResultVoid =
  if nextOpcode != JumpDest:
  return err(opErr(InvalidJumpDest))
 
- # TODO: next check seems redundant
+ # Jump destination must be a valid opcode
  if not c.code.isValidOpcode(jt):
  return err(opErr(InvalidJumpDest))
 

nimbus/evm/interpreter/op_handlers/oph_sysops.nim

@@ -15,6 +15,7 @@
 {.push raises: [].}
 
 import
+ stew/assign2,
  ../../evm_errors,
  ../../computation,
  ../../memory,
@@ -46,7 +47,7 @@ proc returnOp(k: var VmCtx): EvmResultVoid =
  k.cpt.gasCosts[Return].m_handler(k.cpt.memory.len, pos, len),
  reason = "RETURN")
  k.cpt.memory.extend(pos, len)
- k.cpt.output = k.cpt.memory.read(pos, len)
+ assign(k.cpt.output, k.cpt.memory.read(pos, len))
  ok()
 
 
@@ -61,7 +62,7 @@ proc revertOp(k: var VmCtx): EvmResultVoid =
  reason = "REVERT")
 
  k.cpt.memory.extend(pos, len)
- k.cpt.output = k.cpt.memory.read(pos, len)
+ assign(k.cpt.output, k.cpt.memory.read(pos, len))
  # setError(msg, false) will signal cheap revert
  k.cpt.setError(EVMC_REVERT, "REVERT opcode executed", false)
  ok()

nimbus/evm/memory.nim

@@ -11,6 +11,7 @@
 {.push raises: [].}
 
 import
+ stew/assign2,
  ./evm_errors,
  ./interpreter/utils/utils_numeric
 
@@ -20,13 +21,12 @@ type
 
 func new*(_: type EvmMemoryRef): EvmMemoryRef =
  new(result)
- result.bytes = @[]
 
 func len*(memory: EvmMemoryRef): int =
- result = memory.bytes.len
+ memory.bytes.len
 
-func extend*(memory: EvmMemoryRef; startPos: Natural; size: Natural) =
- if size == 0:
+func extend*(memory: EvmMemoryRef; startPos, size: int) =
+ if size <= 0:
  return
  let newSize = ceil32(startPos + size)
  if newSize <= len(memory):
@@ -37,12 +37,10 @@ func new*(_: type EvmMemoryRef, size: Natural): EvmMemoryRef =
  result = EvmMemoryRef.new()
  result.extend(0, size)
 
-func read*(memory: EvmMemoryRef, startPos: Natural, size: Natural): seq[byte] =
- result = newSeq[byte](size)
- if size > 0:
- copyMem(result[0].addr, memory.bytes[startPos].addr, size)
+template read*(memory: EvmMemoryRef, startPos, size: int): openArray[byte] =
+ memory.bytes.toOpenArray(startPos, startPos + size - 1)
 
-template read32Bytes*(memory: EvmMemoryRef, startPos): auto =
+template read32Bytes*(memory: EvmMemoryRef, startPos: int): openArray[byte] =
  memory.bytes.toOpenArray(startPos, startPos + 31)
 
 when defined(evmc_enabled):
@@ -56,8 +54,8 @@ func write*(memory: EvmMemoryRef, startPos: Natural, value: openArray[byte]): Ev
  return
  if startPos + size > memory.len:
  return err(memErr(MemoryFull))
- for z, b in value:
-  memory.bytes[z + startPos] = b
+
+ assign(memory.bytes.toOpenArray(startPos, int(startPos + size) - 1), value)
  ok()
 
 func write*(memory: EvmMemoryRef, startPos: Natural, value: byte): EvmResultVoid =
@@ -71,19 +69,16 @@ func copy*(memory: EvmMemoryRef, dst, src, len: Natural) =
  memory.extend(max(dst, src), len)
  if dst == src:
  return
- elif dst < src:
- for i in 0..<len:
- memory.bytes[dst+i] = memory.bytes[src+i]
- else: # src > dst
- for i in countdown(len-1, 0):
- memory.bytes[dst+i] = memory.bytes[src+i]
+ assign(
+ memory.bytes.toOpenArray(dst, dst + len - 1),
+ memory.bytes.toOpenArray(src, src + len - 1))
 
 func writePadded*(memory: EvmMemoryRef, data: openArray[byte],
  memPos, dataPos, len: Natural) =
 
  memory.extend(memPos, len)
  let
- dataEndPos = dataPos.int64 + len
+ dataEndPos = dataPos + len
  dataStart = min(dataPos, data.len)
  dataEnd = min(data.len, dataEndPos)
  dataLen = dataEnd - dataStart
@@ -95,10 +90,10 @@ func writePadded*(memory: EvmMemoryRef, data: openArray[byte],
  di = dataStart
  mi = memPos
 
- while di < dataEnd:
- memory.bytes[mi] = data[di]
- inc di
-  inc mi
+ assign(
+ memory.bytes.toOpenArray(mi, mi + dataLen - 1),
+ data.toOpenArray(di, di + dataLen - 1))
+ mi += dataLen
 
  # although memory.extend already pad new block of memory
  # with zeros, it can be rewrite by some opcode

tests/test_memory.nim

@@ -45,9 +45,9 @@ proc memoryMain*() =
  test "read returns correct bytes":
  var mem = memory32()
  check mem.write(startPos = 5, value = @[1.byte, 0.byte, 1.byte, 0.byte]).isOk
- check(mem.read(startPos = 5, size = 4) == @[1.byte, 0.byte, 1.byte, 0.byte])
- check(mem.read(startPos = 6, size = 4) == @[0.byte, 1.byte, 0.byte, 0.byte])
- check(mem.read(startPos = 1, size = 3) == @[0.byte, 0.byte, 0.byte])
+ check(@(mem.read(startPos = 5, size = 4)) == @[1.byte, 0.byte, 1.byte, 0.byte])
+ check(@(mem.read(startPos = 6, size = 4)) == @[0.byte, 1.byte, 0.byte, 0.byte])
+ check(@(mem.read(startPos = 1, size = 3)) == @[0.byte, 0.byte, 0.byte])
 
 when isMainModule:
  memoryMain()

tests/test_transaction_json.nim

@@ -13,7 +13,7 @@ import
  unittest2,
  eth/rlp,
  ./test_helpers,
- ../nimbus/[errors, transaction, evm/types],
+ ../nimbus/[errors, transaction],
  ../nimbus/utils/utils
 
 const