mirror of
https://github.com/status-im/nimbus-eth1.git
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411a3cadfa
* renamed nimbus folder to execution_chain * Renamed "nimbus" references to "execution_chain" * fixed wrongly changed http reference * delete snap types file given that it was deleted before this PR merge * missing 'execution_chain' replacement --------- Co-authored-by: pmmiranda <pedro.miranda@nimbus.team>
100 lines
2.8 KiB
Nim
100 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 chronicles, stint, stew/byteutils, ./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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let
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pos = c.pc
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last = pos + size
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if last <= c.bytes.len:
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c.pc = last
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c.code.bytes.toOpenArray(pos, last - 1)
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else:
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c.pc = c.bytes.len
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c.code.bytes.toOpenArray(pos, c.bytes.high)
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func readVmWord*(c: var CodeStream, n: static int): UInt256 {.inline, noinit.} =
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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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UInt256.fromBytesBE(c.read(n))
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func len*(c: CodeStream): int =
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len(c.code)
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template next*(c: var CodeStream): Op =
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# Retrieve the next opcode (or stop) - this is a hot spot in the interpreter
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# and must be kept small for performance
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let
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# uint: range checked manually -> benefit from smaller codegen
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pc = uint(c.pc)
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bytes {.cursor.} = c.code.bytes
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if pc < uint(bytes.len):
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let op = Op(bytes[pc])
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c.pc = cast[int](pc + 1)
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op
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else:
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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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func atEnd*(c: CodeStream): bool =
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c.pc >= c.code.bytes.len
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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 not c.atEnd:
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var op = c.next
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if op >= Push1 and op <= Push32:
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result.add((c.pc - 1, op, "0x" & c.read(op.int - 95).toHex))
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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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