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https://github.com/status-im/nimbus-eth1.git
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768307d91d
It is common for many accounts to share the same code - at the database level, code is stored by hash meaning only one copy exists per unique program but when loaded in memory, a copy is made for each account. Further, every time we execute the code, it must be scanned for invalid jump destinations which slows down EVM exeuction. Finally, the extcodesize call causes code to be loaded even if only the size is needed. This PR improves on all these points by introducing a shared CodeBytesRef type whose code section is immutable and that can be shared between accounts. Further, a dedicated `len` API call is added so that the EXTCODESIZE opcode can operate without polluting the GC and code cache, for cases where only the size is requested - rocksdb will in this case cache the code itself in the row cache meaning that lookup of the code itself remains fast when length is asked for first. With 16k code entries, there's a 90% hit rate which goes up to 99% during the 2.3M attack - the cache significantly lowers memory consumption and execution time not only during this event but across the board.
104 lines
2.8 KiB
Nim
104 lines
2.8 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 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/[sequtils, strutils], chronicles, eth/common, ./interpreter/op_codes, ./code_bytes
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export code_bytes
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type CodeStream* = object
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code: CodeBytesRef
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pc*: int
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func init*(T: type CodeStream, code: CodeBytesRef): T =
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T(code: code)
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func init*(T: type CodeStream, code: sink seq[byte]): T =
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T(code: CodeBytesRef.init(move(code)))
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func init*(T: type CodeStream, code: openArray[byte]): T =
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T(code: CodeBytesRef.init(code))
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func init*(T: type CodeStream, code: openArray[char]): T =
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T(code: CodeBytesRef.init(code))
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template read*(c: var CodeStream, size: int): openArray[byte] =
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if c.pc + size - 1 < c.bytes.len:
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let pos = c.pc
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c.pc += size
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c.code.bytes.toOpenArray(pos, pos + size - 1)
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else:
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c.pc = c.bytes.len
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c.code.bytes.toOpenArray(0, -1)
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func readVmWord*(c: var CodeStream, n: static int): UInt256 =
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## Reads `n` bytes from the code stream and pads
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## the remaining bytes with zeros.
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let result_bytes = cast[ptr array[32, byte]](addr result)
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let last = min(c.pc + n, c.code.bytes.len)
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let toWrite = last - c.pc
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for i in 0 ..< toWrite:
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result_bytes[i] = c.code.bytes[last - i - 1]
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c.pc = last
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func len*(c: CodeStream): int =
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len(c.code)
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func next*(c: var CodeStream): Op =
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if c.pc != c.code.len:
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result = Op(c.code.bytes[c.pc])
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inc c.pc
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else:
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result = Op.Stop
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iterator items*(c: var CodeStream): Op =
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var nextOpcode = c.next()
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while nextOpcode != Op.Stop:
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yield nextOpcode
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nextOpcode = c.next()
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func `[]`*(c: CodeStream, offset: int): Op =
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Op(c.code.bytes[offset])
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func peek*(c: var CodeStream): Op =
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if c.pc < c.code.bytes.len:
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Op(c.code.bytes[c.pc])
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else:
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Op.Stop
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func updatePc*(c: var CodeStream, value: int) =
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c.pc = min(value, len(c))
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func isValidOpcode*(c: CodeStream, position: int): bool =
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c.code.isValidOpcode(position)
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func bytes*(c: CodeStream): lent seq[byte] =
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c.code.bytes()
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proc decompile*(original: CodeStream): seq[(int, Op, string)] =
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# behave as https://etherscan.io/opcode-tool
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var c = CodeStream.init(original.bytes)
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while true:
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var op = c.next
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if op >= Push1 and op <= Push32:
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result.add(
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(
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c.pc - 1,
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op,
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"0x" & c.read(op.int - 95).mapIt($(it.BiggestInt.toHex(2))).join(""),
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)
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)
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elif op != Op.Stop:
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result.add((c.pc - 1, op, ""))
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else:
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result.add((-1, Op.Stop, ""))
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break
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func atEnd*(c: CodeStream): bool =
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c.pc >= c.code.bytes.len
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