From b2ce6d9e70abb5281b498de2ad1f9b1ae41cc275 Mon Sep 17 00:00:00 2001
From: Jordan Hrycaj <jordan@status.im>
Date: Tue, 20 Apr 2021 16:39:32 +0100
Subject: [PATCH] re-arrange functions from v2computation.nim and
 interpreter_dispatch.nim

why:
  step towards breaking circular dependency

details:
  some functions from v2computation.nim have been extracted into
  compu_helper.nim which does not explicitly back-import
  v2computation.nim. all non recursive op handlers now import this source
  file rather than v2computation.nim.

  recursive call/create op handler still need to import v2computation.nim.

  the executeOpcodes() function from interpreter_dispatch.nim has been
  moved to v2computation.nim which allows for <import> rather than
  <include> the interpreter_dispatch.nim source.
---
 nimbus/vm2/compu_helper.nim                   | 132 +++++++++++++++
 .../op_handlers/oph_arithmetic.nim            |   4 +-
 .../interpreter/op_handlers/oph_blockdata.nim |   4 +-
 .../vm2/interpreter/op_handlers/oph_call.nim  |  11 +-
 .../interpreter/op_handlers/oph_create.nim    |   5 +-
 .../interpreter/op_handlers/oph_envinfo.nim   |  25 ++-
 .../vm2/interpreter/op_handlers/oph_hash.nim  |   8 +-
 .../vm2/interpreter/op_handlers/oph_log.nim   |   4 +-
 .../interpreter/op_handlers/oph_memory.nim    |  18 +--
 .../interpreter/op_handlers/oph_sysops.nim    |   4 +-
 nimbus/vm2/interpreter_dispatch.nim           |  36 ++---
 nimbus/vm2/v2computation.nim                  | 153 +++---------------
 nimbus/vm2/v2interpreter.nim                  |  51 +++---
 nimbus/vm_computation.nim                     |  78 ++++++---
 14 files changed, 292 insertions(+), 241 deletions(-)
 create mode 100644 nimbus/vm2/compu_helper.nim

diff --git a/nimbus/vm2/compu_helper.nim b/nimbus/vm2/compu_helper.nim
new file mode 100644
index 000000000..889157737
--- /dev/null
+++ b/nimbus/vm2/compu_helper.nim
@@ -0,0 +1,132 @@
+# Nimbus
+# Copyright (c) 2018 Status Research & Development GmbH
+# Licensed under either of
+#  * Apache License, version 2.0, ([LICENSE-APACHE](LICENSE-APACHE) or
+#    http://www.apache.org/licenses/LICENSE-2.0)
+#  * MIT license ([LICENSE-MIT](LICENSE-MIT) or
+#    http://opensource.org/licenses/MIT)
+# at your option. This file may not be copied, modified, or distributed except
+# according to those terms.
+
+import
+  ../constants,
+  ../db/accounts_cache,
+  ./interpreter/op_codes,
+  ./transaction_tracer,
+  ./v2state,
+  ./v2types,
+  chronicles,
+  eth/[common, keys],
+  options,
+  sets
+
+logScope:
+  topics = "vm compu helper"
+
+when defined(chronicles_log_level):
+  import stew/byteutils
+
+template accountExists*(c: Computation, address: EthAddress): bool =
+  if c.fork >= FkSpurious:
+    not c.vmState.readOnlyStateDB.isDeadAccount(address)
+  else:
+    c.vmState.readOnlyStateDB.accountExists(address)
+
+proc addLogEntry*(c: Computation, log: Log) {.inline.} =
+  c.logEntries.add(log)
+
+template fork*(c: Computation): untyped =
+  c.vmState.fork
+
+template gasCosts*(c: Computation): untyped =
+  c.vmState.gasCosts
+
+template getBalance*(c: Computation, address: EthAddress): Uint256 =
+  c.vmState.readOnlyStateDB.getBalance(address)
+
+template getBlockHash*(c: Computation, blockNumber: Uint256): Hash256 =
+  c.vmState.getAncestorHash(blockNumber.vmWordToBlockNumber)
+
+template getBlockNumber*(c: Computation): Uint256 =
+  c.vmState.blockNumber.blockNumberToVmWord
+
+template getChainId*(c: Computation): uint =
+  c.vmState.chaindb.config.chainId.uint
+
+template getCode*(c: Computation, address: EthAddress): seq[byte] =
+  c.vmState.readOnlyStateDB.getCode(address)
+
+template getCodeHash*(c: Computation, address: EthAddress): Hash256 =
+  let
+    db = c.vmState.readOnlyStateDB
+  if not db.accountExists(address) or db.isEmptyAccount(address):
+    default(Hash256)
+  else:
+    db.getCodeHash(address)
+
+template getCodeSize*(c: Computation, address: EthAddress): uint =
+  uint(c.vmState.readOnlyStateDB.getCodeSize(address))
+
+template getCoinbase*(c: Computation): EthAddress =
+  c.vmState.coinbase
+
+template getDifficulty*(c: Computation): DifficultyInt =
+  c.vmState.difficulty
+
+template getGasLimit*(c: Computation): GasInt =
+  c.vmState.gasLimit
+
+template getGasPrice*(c: Computation): GasInt =
+  c.vmState.txGasPrice
+
+template getOrigin*(c: Computation): EthAddress =
+  c.vmState.txOrigin
+
+template getStorage*(c: Computation, slot: Uint256): Uint256 =
+  c.vmState.readOnlyStateDB.getStorage(c.msg.contractAddress, slot)
+
+template getTimestamp*(c: Computation): int64 =
+  c.vmState.timestamp.toUnix
+
+proc prepareTracer*(c: Computation) {.inline.} =
+  c.vmState.tracer.prepare(c.msg.depth)
+
+proc selfDestruct*(c: Computation, beneficiary: EthAddress) =
+  c.vmState.mutateStateDB:
+    let
+      localBalance = c.getBalance(c.msg.contractAddress)
+      beneficiaryBalance = c.getBalance(beneficiary)
+
+    # Transfer to beneficiary
+    db.setBalance(beneficiary, localBalance + beneficiaryBalance)
+
+    # Zero the balance of the address being deleted.
+    # This must come after sending to beneficiary in case the
+    # contract named itself as the beneficiary.
+    db.setBalance(c.msg.contractAddress, 0.u256)
+
+    trace "SELFDESTRUCT",
+      contractAddress = c.msg.contractAddress.toHex,
+      localBalance = localBalance.toString,
+      beneficiary = beneficiary.toHex
+
+  c.touchedAccounts.incl beneficiary
+  # Register the account to be deleted
+  c.suicides.incl(c.msg.contractAddress)
+
+proc setError*(c: Computation, msg: string, burnsGas = false) {.inline.} =
+  c.error = Error(info: msg, burnsGas: burnsGas)
+
+proc traceOpCodeStarted*(c: Computation, op: Op): int {.inline.} =
+  c.vmState.tracer.traceOpCodeStarted(c, op)
+
+proc traceOpCodeEnded*(c: Computation, op: Op, lastIndex: int) {.inline.} =
+  c.vmState.tracer.traceOpCodeEnded(c, op, lastIndex)
+
+proc tracingEnabled*(c: Computation): bool {.inline.} =
+  TracerFlags.EnableTracing in c.vmState.tracer.flags
+
+
+# deprecated, related to nimvm/evmc implementation
+proc execSelfDestruct*(c: Computation, address: EthAddress) {.deprecated.} =
+  c.selfDestruct(address)
diff --git a/nimbus/vm2/interpreter/op_handlers/oph_arithmetic.nim b/nimbus/vm2/interpreter/op_handlers/oph_arithmetic.nim
index 9acf7434e..bb709e2f6 100644
--- a/nimbus/vm2/interpreter/op_handlers/oph_arithmetic.nim
+++ b/nimbus/vm2/interpreter/op_handlers/oph_arithmetic.nim
@@ -27,8 +27,8 @@ import
 when not breakCircularDependency:
   import
     ../../../constants,
+    ../../compu_helper,
     ../../stack,
-    ../../v2computation,
     ../../v2types,
     ../gas_meter,
     ../utils/v2utils_numeric,
@@ -53,7 +53,7 @@ else:
     var rc: genTupleType(n, UInt256)
     return rc
 
-  # function stubs from v2computation.nim (to satisfy compiler logic)
+  # function stubs from compu_helper.nim (to satisfy compiler logic)
   proc gasCosts(c: Computation): array[Op,int] = result
 
   # function stubs from v2utils_numeric.nim
diff --git a/nimbus/vm2/interpreter/op_handlers/oph_blockdata.nim b/nimbus/vm2/interpreter/op_handlers/oph_blockdata.nim
index e65c7a7fa..2af000e64 100644
--- a/nimbus/vm2/interpreter/op_handlers/oph_blockdata.nim
+++ b/nimbus/vm2/interpreter/op_handlers/oph_blockdata.nim
@@ -26,8 +26,8 @@ import
 
 when not breakCircularDependency:
   import
+    ../../compu_helper,
     ../../stack,
-    ../../v2computation,
     ../../v2state,
     eth/common,
     times
@@ -46,7 +46,7 @@ else:
     var rc: genTupleType(n, UInt256)
     return rc
 
-  # function stubs from v2computation.nim (to satisfy compiler logic)
+  # function stubs from compu_helper.nim (to satisfy compiler logic)
   proc getBalance[T](c: Computation, address: T): Uint256 = 0.u256
   proc getBlockHash(c: Computation, blockNumber: Uint256): Uint256 = 0.u256
   proc getCoinbase(c: Computation): Uint256 = 0.u256
diff --git a/nimbus/vm2/interpreter/op_handlers/oph_call.nim b/nimbus/vm2/interpreter/op_handlers/oph_call.nim
index 643daef8f..703bd12d8 100644
--- a/nimbus/vm2/interpreter/op_handlers/oph_call.nim
+++ b/nimbus/vm2/interpreter/op_handlers/oph_call.nim
@@ -28,8 +28,9 @@ import
 
 when not breakCircularDependency:
   import
-    ../../../db/accounts_cache,
     ../../../constants,
+    ../../../db/accounts_cache,
+    ../../compu_helper,
     ../../stack,
     ../../v2computation,
     ../../v2memory,
@@ -62,12 +63,14 @@ else:
   proc popAddress(x: var Stack): EthAddress = result
   proc popInt(x: var Stack): UInt256 = result
 
-  # function stubs from v2computation.nim (to satisfy compiler logic)
+  # function stubs from compu_helper.nim (to satisfy compiler logic)
   proc gasCosts(c: Computation): array[Op,int] = result
   proc getBalance[T](c: Computation, address: T): Uint256 = result
-  proc newComputation[A,B](v:A, m:B, salt = 0.u256): Computation = new result
-  func shouldBurnGas(c: Computation): bool = result
   proc accountExists(c: Computation, address: EthAddress): bool = result
+
+  # function stubs from v2computation.nim (to satisfy compiler logic)
+  func shouldBurnGas(c: Computation): bool = result
+  proc newComputation[A,B](v:A, m:B, salt = 0.u256): Computation = new result
   proc isSuccess(c: Computation): bool = result
   proc merge(c, child: Computation) = discard
   template chainTo(c, d: Computation, e: untyped) =
diff --git a/nimbus/vm2/interpreter/op_handlers/oph_create.nim b/nimbus/vm2/interpreter/op_handlers/oph_create.nim
index 876b3967c..2549ab4c5 100644
--- a/nimbus/vm2/interpreter/op_handlers/oph_create.nim
+++ b/nimbus/vm2/interpreter/op_handlers/oph_create.nim
@@ -31,6 +31,7 @@ import
 when not breakCircularDependency:
   import
     ../../../constants,
+    ../../compu_helper,
     ../../stack,
     ../../v2computation,
     ../../v2memory,
@@ -56,9 +57,11 @@ else:
   proc peekInt(x: Stack): UInt256 = result
   proc popInt(x: var Stack): UInt256 = result
 
-  # function stubs from v2computation.nim (to satisfy compiler logic)
+  # function stubs from compu_helper.nim (to satisfy compiler logic)
   proc gasCosts(c: Computation): array[Op,int] = result
   proc getBalance[T](c: Computation, address: T): Uint256 = result
+
+  # function stubs from v2computation.nim (to satisfy compiler logic)
   proc newComputation[A,B](v:A, m:B, salt = 0.u256): Computation = new result
   func shouldBurnGas(c: Computation): bool = result
   proc isSuccess(c: Computation): bool = result
diff --git a/nimbus/vm2/interpreter/op_handlers/oph_envinfo.nim b/nimbus/vm2/interpreter/op_handlers/oph_envinfo.nim
index 0a8bae40a..82a6b8ebf 100644
--- a/nimbus/vm2/interpreter/op_handlers/oph_envinfo.nim
+++ b/nimbus/vm2/interpreter/op_handlers/oph_envinfo.nim
@@ -31,24 +31,23 @@ import
 when not breakCircularDependency:
   import
     ../../code_stream,
+    ../../compu_helper,
     ../../stack,
-    ../../v2computation,
     ../../v2memory,
     ../../v2state,
     ../gas_meter,
-    ../v2gas_costs,
     ../utils/v2utils_numeric,
+    ../v2gas_costs,
     eth/common
 
 else:
   import macros
 
-  var
+  const
     GasBalance = 0
     GasExtCode = 42
     GasExtCodeHash = 7
-    blindGasCosts: array[Op,int]
-    blindAddress: EthAddress
+  var
     gasFees: array[Fork,array[0..123,int]]
 
   # copied from stack.nim
@@ -58,19 +57,19 @@ else:
 
   # function stubs from stack.nim (to satisfy compiler logic)
   proc push[T](x: Stack; n: T) = discard
-  proc popAddress(x: var Stack): EthAddress = blindAddress
+  proc popAddress(x: var Stack): EthAddress = result
   proc popInt(x: var Stack, n: static[int]): auto =
     var rc: genTupleType(n, UInt256)
     return rc
 
-  # function stubs from v2computation.nim (to satisfy compiler logic)
-  proc gasCosts(c: Computation): array[Op,int] = blindGasCosts
-  proc getBalance[T](c: Computation, address: T): Uint256 = 0.u256
-  proc getCodeSize[T](c: Computation, address: T): uint = 0
+  # function stubs from compu_helper.nim (to satisfy compiler logic)
+  proc gasCosts(c: Computation): array[Op,int] = result
+  proc getBalance[T](c: Computation, address: T): Uint256 = result
+  proc getCodeSize[T](c: Computation, address: T): uint = result
   proc getCode[T](c: Computation, address: T): seq[byte] = @[]
-  proc getGasPrice(c: Computation): Uint256 =  0.u256
-  proc getOrigin(c: Computation): Uint256 =  0.u256
-  proc getCodeHash[T](c: Computation, address: T):  Uint256 =  0.u256
+  proc getGasPrice(c: Computation): Uint256 = result
+  proc getOrigin(c: Computation): Uint256 = result
+  proc getCodeHash[T](c: Computation, address: T): Uint256 = result
 
   # function stubs from v2utils_numeric.nim
   func cleanMemRef(x: UInt256): int = 0
diff --git a/nimbus/vm2/interpreter/op_handlers/oph_hash.nim b/nimbus/vm2/interpreter/op_handlers/oph_hash.nim
index 51abb37ce..947e8581a 100644
--- a/nimbus/vm2/interpreter/op_handlers/oph_hash.nim
+++ b/nimbus/vm2/interpreter/op_handlers/oph_hash.nim
@@ -28,8 +28,8 @@ import
 when not breakCircularDependency:
   import
     ../../../constants,
+    ../../compu_helper,
     ../../stack,
-    ../../v2computation,
     ../../v2memory,
     ../gas_meter,
     ../utils/v2utils_numeric,
@@ -40,8 +40,6 @@ when not breakCircularDependency:
 else:
   import macros
 
-  var blindGasCosts: array[Op,int]
-
   # copied from stack.nim
   macro genTupleType(len: static[int], elemType: untyped): untyped =
     result = nnkTupleConstr.newNimNode()
@@ -60,8 +58,8 @@ else:
   proc len(mem: Memory): int = 0
   proc extend(mem: var Memory; startPos: Natural; size: Natural) = discard
 
-  # function stubs from v2computation.nim (to satisfy compiler logic)
-  proc gasCosts(c: Computation): array[Op,int] = blindGasCosts
+  # function stubs from compu_helper.nim (to satisfy compiler logic)
+  proc gasCosts(c: Computation): array[Op,int] = result
 
   # function stubs from gas_meter.nim
   proc consumeGas(gasMeter: var GasMeter; amount: int; reason: string) = discard
diff --git a/nimbus/vm2/interpreter/op_handlers/oph_log.nim b/nimbus/vm2/interpreter/op_handlers/oph_log.nim
index 39c091f2c..b4a82df5e 100644
--- a/nimbus/vm2/interpreter/op_handlers/oph_log.nim
+++ b/nimbus/vm2/interpreter/op_handlers/oph_log.nim
@@ -33,8 +33,8 @@ import
 when not breakCircularDependency:
   import
     ../../../constants,
+    ../../compu_helper,
     ../../stack,
-    ../../v2computation,
     ../../v2memory,
     ../../v2types,
     ../gas_meter,
@@ -60,7 +60,7 @@ else:
     var rc: genTupleType(n, UInt256)
     return rc
 
-  # function stubs from v2computation.nim (to satisfy compiler logic)
+  # function stubs from compu_helper.nim (to satisfy compiler logic)
   proc gasCosts(c: Computation): array[Op,int] = blindGasCosts
   proc addLogEntry(c: Computation, log: Log) = discard
 
diff --git a/nimbus/vm2/interpreter/op_handlers/oph_memory.nim b/nimbus/vm2/interpreter/op_handlers/oph_memory.nim
index 50af641fd..f1b6c0ae0 100644
--- a/nimbus/vm2/interpreter/op_handlers/oph_memory.nim
+++ b/nimbus/vm2/interpreter/op_handlers/oph_memory.nim
@@ -31,8 +31,8 @@ when not breakCircularDependency:
   import
     ../../../db/accounts_cache,
     ../../code_stream,
+    ../../compu_helper,
     ../../stack,
-    ../../v2computation,
     ../../v2memory,
     ../../v2state,
     ../../v2types,
@@ -47,8 +47,6 @@ else:
   const
     ColdSloadCost = 42
     WarmStorageReadCost = 43
-  var
-    blindGasCosts: array[Op,int]
 
   # copied from stack.nim
   macro genTupleType(len: static[int], elemType: untyped): untyped =
@@ -62,9 +60,9 @@ else:
     var rc: genTupleType(n, UInt256)
     return rc
 
-  # function stubs from v2computation.nim (to satisfy compiler logic)
-  proc getStorage(c: Computation, slot: Uint256): Uint256 = 0.u256
-  proc gasCosts(c: Computation): array[Op,int] = blindGasCosts
+  # function stubs from compu_helper.nim (to satisfy compiler logic)
+  proc getStorage(c: Computation, slot: Uint256): Uint256 = result
+  proc gasCosts(c: Computation): array[Op,int] = result
 
   # function stubs from v2utils_numeric.nim
   func cleanMemRef(x: UInt256): int = 0
@@ -81,7 +79,7 @@ else:
   proc isValidOpcode(c: CodeStream, position: int): bool = false
 
   # function stubs from v2state.nim
-  proc readOnlyStateDB(x: BaseVMState): ReadOnlyStateDB = x.accountDb
+  proc readOnlyStateDB(x: BaseVMState): ReadOnlyStateDB = result
   template mutateStateDB(vmState: BaseVMState, body: untyped) =
     block:
       var db {.inject.} = vmState.accountDb
@@ -99,14 +97,14 @@ else:
       s_originalValue: Uint256
     else:
       discard
-  proc c_handler(x: int; y: Uint256, z: GasParams): (int,int) = (0,0)
+  proc c_handler(x: int; y: Uint256, z: GasParams): (int,int) = result
   proc m_handler(x: int; curMemSize, memOffset, memLen: int64): int = 0
 
   # function stubs from state_db.nim
-  proc getCommittedStorage[A,B](x: A; y: B; z: Uint256): Uint256 = 0.u256
+  proc getCommittedStorage[A,B](x: A; y: B; z: Uint256): Uint256 = result
 
   # function stubs from accounts_cache.nim:
-  func inAccessList[A,B](ac: A; address: B; slot: UInt256): bool = false
+  func inAccessList[A,B](ac: A; address: B; slot: UInt256): bool = result
   proc accessList[A,B](ac: var A; address: B; slot: UInt256) = discard
   proc setStorage[A,B](ac: var A; address: B, slot, value: UInt256) = discard
 
diff --git a/nimbus/vm2/interpreter/op_handlers/oph_sysops.nim b/nimbus/vm2/interpreter/op_handlers/oph_sysops.nim
index 2f472e1e3..5b6686772 100644
--- a/nimbus/vm2/interpreter/op_handlers/oph_sysops.nim
+++ b/nimbus/vm2/interpreter/op_handlers/oph_sysops.nim
@@ -29,8 +29,8 @@ import
 when not breakCircularDependency:
   import
     ../../../db/accounts_cache,
+    ../../compu_helper,
     ../../stack,
-    ../../v2computation,
     ../../v2memory,
     ../../v2state,
     ../../v2types,
@@ -58,7 +58,7 @@ else:
     var rc: genTupleType(n, UInt256)
     return rc
 
-  # function stubs from v2computation.nim (to satisfy compiler logic)
+  # function stubs from compu_helper.nim (to satisfy compiler logic)
   proc gasCosts(c: Computation): array[Op,int] = result
   proc setError(c: Computation, msg: string, burnsGas = false) = discard
   proc selfDestruct(c: Computation, address: EthAddress) = discard
diff --git a/nimbus/vm2/interpreter_dispatch.nim b/nimbus/vm2/interpreter_dispatch.nim
index a9b25db7b..d41e6a560 100644
--- a/nimbus/vm2/interpreter_dispatch.nim
+++ b/nimbus/vm2/interpreter_dispatch.nim
@@ -1,20 +1,24 @@
 # Nimbus
 # Copyright (c) 2018 Status Research & Development GmbH
 # Licensed under either of
-#  * Apache License, version 2.0, ([LICENSE-APACHE](LICENSE-APACHE) or http://www.apache.org/licenses/LICENSE-2.0)
-#  * MIT license ([LICENSE-MIT](LICENSE-MIT) or http://opensource.org/licenses/MIT)
-# at your option. This file may not be copied, modified, or distributed except according to those terms.
+#  * Apache License, version 2.0, ([LICENSE-APACHE](LICENSE-APACHE) or
+#    http://www.apache.org/licenses/LICENSE-2.0)
+#  * MIT license ([LICENSE-MIT](LICENSE-MIT) or
+#    http://opensource.org/licenses/MIT)
+# at your option. This file may not be copied, modified, or distributed except
+# according to those terms.
 
 import
-  chronicles,
+  ./compu_helper,
   ./interpreter/[gas_meter, op_handlers, op_handlers/oph_defs, v2gas_costs],
-  ./code_stream, ./v2types, ./v2precompiles
+  ./code_stream,
+  ./v2types,
+  chronicles
 
 logScope:
   topics = "vm opcode"
 
-
-proc selectVM(c: Computation, fork: Fork) {.gcsafe.} =
+proc selectVM*(c: Computation, fork: Fork) {.gcsafe.} =
   var desc: Vm2Ctx
 
   if c.tracingEnabled:
@@ -51,21 +55,3 @@ proc selectVM(c: Computation, fork: Fork) {.gcsafe.} =
     else:
       discard
 
-
-proc executeOpcodes(c: Computation) =
-  let fork = c.fork
-
-  block:
-    if not c.continuation.isNil:
-      c.continuation = nil
-    elif c.execPrecompiles(fork):
-      break
-
-    try:
-      c.selectVM(fork)
-    except CatchableError as e:
-      c.setError(&"Opcode Dispatch Error msg={e.msg}, depth={c.msg.depth}", true)
-
-  if c.isError() and c.continuation.isNil:
-    if c.tracingEnabled: c.traceError()
-    debug "executeOpcodes error", msg=c.error.info
diff --git a/nimbus/vm2/v2computation.nim b/nimbus/vm2/v2computation.nim
index dcbc6fd89..46d2775fe 100644
--- a/nimbus/vm2/v2computation.nim
+++ b/nimbus/vm2/v2computation.nim
@@ -9,92 +9,19 @@ when defined(evmc_enabled):
   {.fatal: "Flags \"evmc_enabled\" and \"vm2_enabled\" are mutually exclusive"}
 
 import
-  chronicles, strformat, macros, options, times,
+  chronicles, strformat, macros, options,
   sets, eth/[common, keys],
-  ../constants, ../errors,
-  ./interpreter/[v2opcode_values, gas_meter, v2gas_costs, v2forks],
+  ../constants,
+  ./compu_helper,
+  ./interpreter/[op_codes, gas_meter, v2gas_costs, v2forks],
   ./code_stream, ./memory_defs, ./v2message, ./stack, ./v2types, ./v2state,
-  ../db/[accounts_cache, db_chain],
-  ../utils/header, ./v2precompiles,
+  ../db/accounts_cache,
+  ./v2precompiles,
   ./transaction_tracer, ../utils
 
-when defined(chronicles_log_level):
-  import stew/byteutils
-
 logScope:
   topics = "vm computation"
 
-template getCoinbase*(c: Computation): EthAddress =
-  block:
-    c.vmState.coinbase
-
-template getTimestamp*(c: Computation): int64 =
-  block:
-    c.vmState.timestamp.toUnix
-
-template getBlockNumber*(c: Computation): Uint256 =
-  block:
-    c.vmState.blockNumber.blockNumberToVmWord
-
-template getDifficulty*(c: Computation): DifficultyInt =
-  block:
-    c.vmState.difficulty
-
-template getGasLimit*(c: Computation): GasInt =
-  block:
-    c.vmState.gasLimit
-
-template getChainId*(c: Computation): uint =
-  block:
-    c.vmState.chaindb.config.chainId.uint
-
-template getOrigin*(c: Computation): EthAddress =
-  block:
-    c.vmState.txOrigin
-
-template getGasPrice*(c: Computation): GasInt =
-  block:
-    c.vmState.txGasPrice
-
-template getBlockHash*(c: Computation, blockNumber: Uint256): Hash256 =
-  block:
-    c.vmState.getAncestorHash(blockNumber.vmWordToBlockNumber)
-
-template accountExists*(c: Computation, address: EthAddress): bool =
-  block:
-    if c.fork >= FkSpurious:
-      not c.vmState.readOnlyStateDB.isDeadAccount(address)
-    else:
-      c.vmState.readOnlyStateDB.accountExists(address)
-
-template getStorage*(c: Computation, slot: Uint256): Uint256 =
-  block:
-    c.vmState.readOnlyStateDB.getStorage(c.msg.contractAddress, slot)
-
-template getBalance*(c: Computation, address: EthAddress): Uint256 =
-  block:
-    c.vmState.readOnlyStateDB.getBalance(address)
-
-template getCodeSize*(c: Computation, address: EthAddress): uint =
-  block:
-    uint(c.vmState.readOnlyStateDB.getCodeSize(address))
-
-template getCodeHash*(c: Computation, address: EthAddress): Hash256 =
-  block:
-    let db = c.vmState.readOnlyStateDB
-    if not db.accountExists(address) or db.isEmptyAccount(address):
-      default(Hash256)
-    else:
-      db.getCodeHash(address)
-
-template selfDestruct*(c: Computation, address: EthAddress) =
-  block:
-    c.execSelfDestruct(address)
-
-template getCode*(c: Computation, address: EthAddress): seq[byte] =
-  block:
-    c.vmState.readOnlyStateDB.getCode(address)
-
 proc generateContractAddress(c: Computation, salt: Uint256): EthAddress =
   if c.msg.kind == evmcCreate:
     let creationNonce = c.vmState.readOnlyStateDb().getNonce(c.msg.sender)
@@ -102,7 +29,6 @@ proc generateContractAddress(c: Computation, salt: Uint256): EthAddress =
   else:
     result = generateSafeAddress(c.msg.sender, salt, c.msg.data)
 
-import stew/byteutils
 
 proc newComputation*(vmState: BaseVMState, message: Message, salt= 0.u256): Computation =
   new result
@@ -122,13 +48,6 @@ proc newComputation*(vmState: BaseVMState, message: Message, salt= 0.u256): Comp
   else:
     result.code = newCodeStream(vmState.readOnlyStateDb.getCode(message.codeAddress))
 
-
-template gasCosts*(c: Computation): untyped =
-  c.vmState.gasCosts
-
-template fork*(c: Computation): untyped =
-  c.vmState.fork
-
 proc isOriginComputation*(c: Computation): bool =
   # Is this computation the computation initiated by a transaction
   c.msg.sender == c.vmState.txOrigin
@@ -158,9 +77,6 @@ proc dispose*(c: Computation) {.inline.} =
 proc rollback*(c: Computation) =
   c.vmState.accountDb.rollback(c.savePoint)
 
-proc setError*(c: Computation, msg: string, burnsGas = false) {.inline.} =
-  c.error = Error(info: msg, burnsGas: burnsGas)
-
 proc writeContract*(c: Computation, fork: Fork): bool {.gcsafe.} =
   result = true
 
@@ -306,32 +222,6 @@ proc merge*(c, child: Computation) =
   c.suicides.incl child.suicides
   c.touchedAccounts.incl child.touchedAccounts
 
-proc execSelfDestruct*(c: Computation, beneficiary: EthAddress) =
-  c.vmState.mutateStateDB:
-    let
-      localBalance = c.getBalance(c.msg.contractAddress)
-      beneficiaryBalance = c.getBalance(beneficiary)
-
-    # Transfer to beneficiary
-    db.setBalance(beneficiary, localBalance + beneficiaryBalance)
-
-    # Zero the balance of the address being deleted.
-    # This must come after sending to beneficiary in case the
-    # contract named itself as the beneficiary.
-    db.setBalance(c.msg.contractAddress, 0.u256)
-
-    trace "SELFDESTRUCT",
-      contractAddress = c.msg.contractAddress.toHex,
-      localBalance = localBalance.toString,
-      beneficiary = beneficiary.toHex
-
-  c.touchedAccounts.incl beneficiary
-  # Register the account to be deleted
-  c.suicides.incl(c.msg.contractAddress)
-
-proc addLogEntry*(c: Computation, log: Log) {.inline.} =
-  c.logEntries.add(log)
-
 proc getGasRefund*(c: Computation): GasInt =
   if c.isSuccess:
     result = c.gasMeter.gasRefunded
@@ -340,19 +230,28 @@ proc refundSelfDestruct*(c: Computation) =
   let cost = gasFees[c.fork][RefundSelfDestruct]
   c.gasMeter.refundGas(cost * c.suicides.len)
 
-proc tracingEnabled*(c: Computation): bool {.inline.} =
-  EnableTracing in c.vmState.tracer.flags
-
-proc traceOpCodeStarted*(c: Computation, op: Op): int {.inline.} =
-  c.vmState.tracer.traceOpCodeStarted(c, op)
-
-proc traceOpCodeEnded*(c: Computation, op: Op, lastIndex: int) {.inline.} =
-  c.vmState.tracer.traceOpCodeEnded(c, op, lastIndex)
 
 proc traceError*(c: Computation) {.inline.} =
   c.vmState.tracer.traceError(c)
 
-proc prepareTracer*(c: Computation) {.inline.} =
-  c.vmState.tracer.prepare(c.msg.depth)
 
-include interpreter_dispatch
+import interpreter_dispatch
+
+proc executeOpcodes(c: Computation) =
+  let fork = c.fork
+
+  block:
+    if not c.continuation.isNil:
+      c.continuation = nil
+    elif c.execPrecompiles(fork):
+      break
+
+    try:
+      c.selectVM(fork)
+    except CatchableError as e:
+      c.setError(
+        &"Opcode Dispatch Error msg={e.msg}, depth={c.msg.depth}", true)
+
+  if c.isError() and c.continuation.isNil:
+    if c.tracingEnabled: c.traceError()
+    debug "executeOpcodes error", msg=c.error.info
diff --git a/nimbus/vm2/v2interpreter.nim b/nimbus/vm2/v2interpreter.nim
index edaff9765..b889aecf7 100644
--- a/nimbus/vm2/v2interpreter.nim
+++ b/nimbus/vm2/v2interpreter.nim
@@ -35,50 +35,53 @@ export
 # Used in vm_types. Beware of recursive dependencies
 
 # see vm_computation
+import
+  ./compu_helper as xmc
+export
+  xmc.accountExists,
+  xmc.addLogEntry,
+  xmc.fork,
+  xmc.getBalance,
+  xmc.getBlockHash,
+  xmc.getBlockNumber,
+  xmc.getChainId,
+  xmc.getCode,
+  xmc.getCodeHash,
+  xmc.getCodeSize,
+  xmc.getCoinbase,
+  xmc.getDifficulty,
+  xmc.getGasLimit,
+  xmc.getGasPrice,
+  xmc.getOrigin,
+  xmc.getStorage,
+  xmc.getTimestamp,
+  xmc.prepareTracer,
+  xmc.selfDestruct,
+  xmc.setError,
+  xmc.traceOpCodeEnded,
+  xmc.traceOpCodeStarted,
+  xmc.tracingEnabled
+
 import
   ./v2computation as vmc
 export
-  vmc.accountExists,
-  vmc.addLogEntry,
   vmc.commit,
   vmc.dispose,
   vmc.execCallOrCreate,
   vmc.chainTo,
-  vmc.execSelfDestruct,
   vmc.executeOpcodes,
-  vmc.fork,
-  vmc.getBalance,
-  vmc.getBlockHash,
-  vmc.getBlockNumber,
-  vmc.getChainId,
-  vmc.getCode,
-  vmc.getCodeHash,
-  vmc.getCodeSize,
-  vmc.getCoinbase,
-  vmc.getDifficulty,
-  vmc.getGasLimit,
-  vmc.getGasPrice,
   vmc.getGasRefund,
-  vmc.getOrigin,
-  vmc.getStorage,
-  vmc.getTimestamp,
   vmc.isError,
   vmc.isOriginComputation,
   vmc.isSuccess,
   vmc.isSuicided,
   vmc.merge,
   vmc.newComputation,
-  vmc.prepareTracer,
   vmc.refundSelfDestruct,
   vmc.rollback,
-  vmc.selfDestruct,
-  vmc.setError,
   vmc.shouldBurnGas,
   vmc.snapshot,
   vmc.traceError,
-  vmc.traceOpCodeEnded,
-  vmc.traceOpCodeStarted,
-  vmc.tracingEnabled,
   vmc.writeContract
 
 
diff --git a/nimbus/vm_computation.nim b/nimbus/vm_computation.nim
index 64c13553d..55dc7f009 100644
--- a/nimbus/vm_computation.nim
+++ b/nimbus/vm_computation.nim
@@ -14,52 +14,82 @@
 when defined(evmc_enabled) or not defined(vm2_enabled):
   import
     ./vm/computation as vmc
+
+  export
+    vmc.accountExists,
+    vmc.addLogEntry,
+    vmc.execSelfDestruct,
+    vmc.fork,
+    vmc.getBalance,
+    vmc.getBlockHash,
+    vmc.getBlockNumber,
+    vmc.getChainId,
+    vmc.getCode,
+    vmc.getCodeHash,
+    vmc.getCodeSize,
+    vmc.getCoinbase,
+    vmc.getDifficulty,
+    vmc.getGasLimit,
+    vmc.getGasPrice,
+    vmc.getOrigin,
+    vmc.getStorage,
+    vmc.getTimestamp,
+    vmc.selfDestruct,
+    vmc.setError,
+    vmc.prepareTracer,
+    vmc.traceOpCodeEnded,
+    vmc.traceOpCodeStarted,
+    vmc.tracingEnabled
+
 else:
   import
+    ./vm2/compu_helper as xmc,
     ./vm2/v2computation as vmc
 
+  export
+    xmc.accountExists,
+    xmc.addLogEntry,
+    xmc.execSelfDestruct,
+    xmc.fork,
+    xmc.getBalance,
+    xmc.getBlockHash,
+    xmc.getBlockNumber,
+    xmc.getChainId,
+    xmc.getCode,
+    xmc.getCodeHash,
+    xmc.getCodeSize,
+    xmc.getCoinbase,
+    xmc.getDifficulty,
+    xmc.getGasLimit,
+    xmc.getGasPrice,
+    xmc.getOrigin,
+    xmc.getStorage,
+    xmc.getTimestamp,
+    xmc.prepareTracer,
+    xmc.selfDestruct,
+    xmc.setError,
+    xmc.traceOpCodeEnded,
+    xmc.traceOpCodeStarted,
+    xmc.tracingEnabled
+
 export
-  vmc.accountExists,
-  vmc.addLogEntry,
   vmc.commit,
   vmc.dispose,
   vmc.execCallOrCreate,
   vmc.chainTo,
-  vmc.execSelfDestruct,
   vmc.executeOpcodes,
-  vmc.fork,
-  vmc.getBalance,
-  vmc.getBlockHash,
-  vmc.getBlockNumber,
-  vmc.getChainId,
-  vmc.getCode,
-  vmc.getCodeHash,
-  vmc.getCodeSize,
-  vmc.getCoinbase,
-  vmc.getDifficulty,
-  vmc.getGasLimit,
-  vmc.getGasPrice,
   vmc.getGasRefund,
-  vmc.getOrigin,
-  vmc.getStorage,
-  vmc.getTimestamp,
   vmc.isError,
   vmc.isOriginComputation,
   vmc.isSuccess,
   vmc.isSuicided,
   vmc.merge,
   vmc.newComputation,
-  vmc.prepareTracer,
   vmc.refundSelfDestruct,
   vmc.rollback,
-  vmc.selfDestruct,
-  vmc.setError,
   vmc.shouldBurnGas,
   vmc.snapshot,
   vmc.traceError,
-  vmc.traceOpCodeEnded,
-  vmc.traceOpCodeStarted,
-  vmc.tracingEnabled,
   vmc.writeContract
 
 # End