137 lines
4.7 KiB
Nim
137 lines
4.7 KiB
Nim
# Nimbus
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# Copyright (c) 2018 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 http://www.apache.org/licenses/LICENSE-2.0)
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# * MIT license ([LICENSE-MIT](LICENSE-MIT) or http://opensource.org/licenses/MIT)
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# at your option. This file may not be copied, modified, or distributed except according to those terms.
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import
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std/[strformat, strutils, sequtils, macros],
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chronicles, eth/common,
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../errors, ./validation
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logScope:
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topics = "vm stack"
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type
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Stack* = ref object of RootObj
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values*: seq[StackElement]
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StackElement = UInt256
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template ensureStackLimit: untyped =
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if len(stack.values) > 1023:
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raise newException(FullStack, "Stack limit reached")
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proc len*(stack: Stack): int {.inline.} =
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len(stack.values)
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proc toStackElement(v: UInt256, elem: var StackElement) {.inline.} = elem = v
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proc toStackElement(v: uint | int | GasInt, elem: var StackElement) {.inline.} = elem = v.u256
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proc toStackElement(v: EthAddress, elem: var StackElement) {.inline.} = elem.initFromBytesBE(v)
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proc toStackElement(v: MDigest, elem: var StackElement) {.inline.} = elem.initFromBytesBE(v.data, allowPadding = false)
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proc fromStackElement(elem: StackElement, v: var UInt256) {.inline.} = v = elem
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proc fromStackElement(elem: StackElement, v: var EthAddress) {.inline.} = v[0 .. ^1] = elem.toByteArrayBE().toOpenArray(12, 31)
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proc fromStackElement(elem: StackElement, v: var Hash256) {.inline.} = v.data = elem.toByteArrayBE()
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proc fromStackElement(elem: StackElement, v: var Topic) {.inline.} = v = elem.toByteArrayBE()
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proc toStackElement(v: openArray[byte], elem: var StackElement) {.inline.} =
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# TODO: This needs to go
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validateStackItem(v) # This is necessary to pass stack tests
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elem.initFromBytesBE(v)
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proc pushAux[T](stack: var Stack, value: T) =
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ensureStackLimit()
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stack.values.setLen(stack.values.len + 1)
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toStackElement(value, stack.values[^1])
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proc push*(stack: var Stack, value: uint | int | GasInt | UInt256 | EthAddress | Hash256) {.inline.} =
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pushAux(stack, value)
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proc push*(stack: var Stack, value: openArray[byte]) {.inline.} =
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# TODO: This needs to go...
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pushAux(stack, value)
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proc ensurePop(elements: Stack, a: int) =
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let num = elements.len
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let expected = a
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if num < expected:
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raise newException(InsufficientStack,
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&"Stack underflow: expected {expected} elements, got {num} instead.")
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proc popAux[T](stack: var Stack, value: var T) =
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ensurePop(stack, 1)
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fromStackElement(stack.values[^1], value)
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stack.values.setLen(stack.values.len - 1)
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proc internalPopTuple(stack: var Stack, v: var tuple, tupleLen: static[int]) =
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ensurePop(stack, tupleLen)
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var i = 0
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let sz = stack.values.high
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for f in fields(v):
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fromStackElement(stack.values[sz - i], f)
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inc i
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stack.values.setLen(sz - tupleLen + 1)
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proc popInt*(stack: var Stack): UInt256 {.inline.} =
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popAux(stack, result)
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macro genTupleType(len: static[int], elemType: untyped): untyped =
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result = nnkTupleConstr.newNimNode()
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for i in 0 ..< len: result.add(elemType)
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proc popInt*(stack: var Stack, numItems: static[int]): auto {.inline.} =
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var r: genTupleType(numItems, UInt256)
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stack.internalPopTuple(r, numItems)
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return r
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proc popAddress*(stack: var Stack): EthAddress {.inline.} =
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popAux(stack, result)
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proc popTopic*(stack: var Stack): Topic {.inline.} =
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popAux(stack, result)
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proc newStack*(): Stack =
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new(result)
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result.values = @[]
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proc swap*(stack: var Stack, position: int) =
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## Perform a SWAP operation on the stack
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var idx = position + 1
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if idx < len(stack) + 1:
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(stack.values[^1], stack.values[^idx]) = (stack.values[^idx], stack.values[^1])
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else:
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raise newException(InsufficientStack,
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&"Insufficient stack items for SWAP{position}")
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template getInt(x: int): int = x
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proc dup*(stack: var Stack, position: int | UInt256) =
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## Perform a DUP operation on the stack
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let position = position.getInt
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if position in 1 .. stack.len:
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stack.push(stack.values[^position])
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else:
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raise newException(InsufficientStack,
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&"Insufficient stack items for DUP{position}")
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proc peek*(stack: Stack): UInt256 =
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# This should be used only for testing purposes!
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fromStackElement(stack.values[^1], result)
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proc `$`*(stack: Stack): string =
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let values = stack.values.mapIt(&" {$it}").join("\n")
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&"Stack:\n{values}"
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proc `[]`*(stack: Stack, i: BackwardsIndex, T: typedesc): T =
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ensurePop(stack, int(i))
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fromStackElement(stack.values[i], result)
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proc peekInt*(stack: Stack): UInt256 =
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ensurePop(stack, 1)
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fromStackElement(stack.values[^1], result)
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proc top*(stack: Stack, value: uint | int | GasInt | UInt256 | EthAddress | Hash256) {.inline.} =
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toStackElement(value, stack.values[^1])
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