295 lines
9.0 KiB
Nim
295 lines
9.0 KiB
Nim
# Nimbus
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# Copyright (c) 2018-2024 Status Research & Development GmbH
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# Licensed under either of
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# * Apache License, version 2.0, ([LICENSE-APACHE](LICENSE-APACHE) or
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# http://www.apache.org/licenses/LICENSE-2.0)
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# * MIT license ([LICENSE-MIT](LICENSE-MIT) or
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# http://opensource.org/licenses/MIT)
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# at your option. This file may not be copied, modified, or distributed except
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# according to those terms.
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const
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# help with low memory when compiling selectVM() function
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lowmem {.intdefine.}: int = 0
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lowMemoryCompileTime {.used.} = lowmem > 0
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import
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std/[macros, strformat],
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pkg/[chronicles, chronos, stew/byteutils],
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".."/[constants, db/ledger],
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"."/[code_stream, computation, evm_errors],
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"."/[message, precompiles, state, types],
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./interpreter/[op_dispatcher, gas_costs]
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{.push raises: [].}
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logScope:
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topics = "vm opcode"
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# ------------------------------------------------------------------------------
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# Private functions
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# ------------------------------------------------------------------------------
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const
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supportedOS = defined(windows) or defined(linux) or defined(macosx)
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optimizationCondition = not lowMemoryCompileTime and defined(release) and supportedOS
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when optimizationCondition:
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# this is a top level pragma since nim 1.6.16
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{.optimization: speed.}
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proc runVM(
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c: VmCpt,
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shouldPrepareTracer: bool,
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fork: static EVMFork,
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tracingEnabled: static bool,
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): EvmResultVoid =
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## VM instruction handler main loop - for each fork, a distinc version of
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## this function is instantiated so that selection of fork-specific
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## versions of functions happens only once
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# It's important not to re-prepare the tracer after
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# an async operation, only after a call/create.
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#
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# That is, tracingEnabled is checked in many places, and
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# indicates something like, "Do we want tracing to be
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# enabled?", whereas shouldPrepareTracer is more like,
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# "Are we at a spot right now where we want to re-initialize
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# the tracer?"
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when tracingEnabled:
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if shouldPrepareTracer:
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c.prepareTracer()
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while true:
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{.computedGoto.}
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c.instr = c.code.next()
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dispatchInstr(fork, tracingEnabled, c.instr, c)
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ok()
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macro selectVM(v: VmCpt, shouldPrepareTracer: bool, fork: EVMFork, tracingEnabled: bool): EvmResultVoid =
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# Generate opcode dispatcher that calls selectVM with a literal for each fork:
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#
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# case fork
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# of A: runVM(v, A, ...)
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# ...
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let caseStmt = nnkCaseStmt.newTree(fork)
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for fork in EVMFork:
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let
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forkVal = quote:
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`fork`
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call = quote:
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case `tracingEnabled`
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of false: runVM(`v`, `shouldPrepareTracer`, `forkVal`, `false`)
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of true: runVM(`v`, `shouldPrepareTracer`, `forkVal`, `true`)
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caseStmt.add nnkOfBranch.newTree(forkVal, call)
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caseStmt
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proc beforeExecCall(c: Computation) =
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c.snapshot()
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if c.msg.kind == EVMC_CALL:
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c.vmState.mutateStateDB:
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db.subBalance(c.msg.sender, c.msg.value)
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db.addBalance(c.msg.contractAddress, c.msg.value)
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proc afterExecCall(c: Computation) =
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## Collect all of the accounts that *may* need to be deleted based on EIP161
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## https://github.com/ethereum/EIPs/blob/master/EIPS/eip-161.md
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## also see: https://github.com/ethereum/EIPs/issues/716
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if c.isError or c.fork >= FkByzantium:
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if c.msg.contractAddress == RIPEMD_ADDR:
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# Special case to account for geth+parity bug
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c.vmState.stateDB.ripemdSpecial()
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if c.isSuccess:
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c.commit()
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else:
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c.rollback()
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proc beforeExecCreate(c: Computation): bool =
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c.vmState.mutateStateDB:
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let nonce = db.getNonce(c.msg.sender)
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if nonce + 1 < nonce:
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let sender = c.msg.sender.toHex
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c.setError(
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"Nonce overflow when sender=" & sender & " wants to create contract", false
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)
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return true
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db.setNonce(c.msg.sender, nonce + 1)
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# We add this to the access list _before_ taking a snapshot.
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# Even if the creation fails, the access-list change should not be rolled
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# back EIP2929
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if c.fork >= FkBerlin:
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db.accessList(c.msg.contractAddress)
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c.snapshot()
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if c.vmState.readOnlyStateDB().contractCollision(c.msg.contractAddress):
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let blurb = c.msg.contractAddress.toHex
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c.setError("Address collision when creating contract address=" & blurb, true)
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c.rollback()
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return true
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c.vmState.mutateStateDB:
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db.subBalance(c.msg.sender, c.msg.value)
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db.addBalance(c.msg.contractAddress, c.msg.value)
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db.clearStorage(c.msg.contractAddress)
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if c.fork >= FkSpurious:
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# EIP161 nonce incrementation
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db.incNonce(c.msg.contractAddress)
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return false
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proc afterExecCreate(c: Computation) =
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if c.isSuccess:
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# This can change `c.isSuccess`.
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c.writeContract()
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# Contract code should never be returned to the caller. Only data from
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# `REVERT` is returned after a create. Clearing in this branch covers the
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# right cases, particularly important with EVMC where it must be cleared.
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if c.output.len > 0:
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c.output = @[]
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if c.isSuccess:
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c.commit()
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else:
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c.rollback()
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const MsgKindToOp: array[CallKind, Op] =
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[Call, DelegateCall, CallCode, Create, Create2, EofCreate]
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func msgToOp(msg: Message): Op =
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if EVMC_STATIC in msg.flags:
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return StaticCall
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MsgKindToOp[msg.kind]
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proc beforeExec(c: Computation): bool =
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if c.msg.depth > 0:
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c.vmState.captureEnter(
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c,
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msgToOp(c.msg),
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c.msg.sender,
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c.msg.contractAddress,
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c.msg.data,
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c.msg.gas,
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c.msg.value,
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)
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if not c.msg.isCreate:
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c.beforeExecCall()
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false
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else:
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c.beforeExecCreate()
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proc afterExec(c: Computation) =
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if not c.msg.isCreate:
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c.afterExecCall()
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else:
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c.afterExecCreate()
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if c.msg.depth > 0:
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let gasUsed = c.msg.gas - c.gasMeter.gasRemaining
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c.vmState.captureExit(c, c.output, gasUsed, c.errorOpt)
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# ------------------------------------------------------------------------------
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# Public functions
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# ------------------------------------------------------------------------------
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template handleEvmError(x: EvmErrorObj) =
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let
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msg = $x.code
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depth = $(c.msg.depth + 1) # plus one to match tracer depth, and avoid confusion
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c.setError("Opcode Dispatch Error: " & msg & ", depth=" & depth, true)
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proc executeOpcodes*(c: Computation, shouldPrepareTracer: bool = true) =
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let fork = c.fork
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block blockOne:
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if c.continuation.isNil and c.execPrecompiles(fork):
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break blockOne
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let cont = c.continuation
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if not cont.isNil:
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c.continuation = nil
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cont().isOkOr:
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handleEvmError(error)
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break blockOne
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let nextCont = c.continuation
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if not nextCont.isNil:
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# Return up to the caller, which will run the child
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# and then call this proc again.
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break blockOne
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# FIXME-Adam: I hate how convoluted this is. See also the comment in
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# op_dispatcher.nim. The idea here is that we need to call
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# traceOpCodeEnded at the end of the opcode (and only if there
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# hasn't been an exception thrown); otherwise we run into problems
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# if an exception (e.g. out of gas) is thrown during a continuation.
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# So this code says, "If we've just run a continuation, but there's
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# no *subsequent* continuation, then the opcode is done."
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if c.tracingEnabled and not (cont.isNil) and nextCont.isNil:
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c.traceOpCodeEnded(c.instr, c.opIndex)
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if c.instr == Return or c.instr == Revert or c.instr == SelfDestruct:
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break blockOne
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c.selectVM(shouldPrepareTracer, fork, c.tracingEnabled).isOkOr:
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handleEvmError(error)
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break blockOne # this break is not needed but make the flow clear
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if c.isError() and c.continuation.isNil:
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if c.tracingEnabled:
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c.traceError()
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when vm_use_recursion:
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# Recursion with tiny stack frame per level.
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proc execCallOrCreate*(c: Computation) =
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if not c.beforeExec():
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c.executeOpcodes()
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while not c.continuation.isNil:
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# If there's a continuation, then it's because there's either
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# a child (i.e. call or create)
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when evmc_enabled:
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c.res = c.host.call(c.child[])
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else:
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execCallOrCreate(c.child)
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c.child = nil
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c.executeOpcodes()
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c.afterExec()
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c.dispose()
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else:
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proc execCallOrCreate*(cParam: Computation) =
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var (c, before, shouldPrepareTracer) = (cParam, true, true)
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# No actual recursion, but simulate recursion including before/after/dispose.
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while true:
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while true:
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if before and c.beforeExec():
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break
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c.executeOpcodes(shouldPrepareTracer)
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if c.continuation.isNil:
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c.afterExec()
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break
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(before, shouldPrepareTracer, c.child, c, c.parent) =
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(true, true, nil.Computation, c.child, c)
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if c.parent.isNil:
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break
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c.dispose()
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(before, shouldPrepareTracer, c.parent, c) =
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(false, true, nil.Computation, c.parent)
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while not c.isNil:
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c.dispose()
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c = c.parent
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# ------------------------------------------------------------------------------
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# End
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# ------------------------------------------------------------------------------
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