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Add EIP: Introspection precompiles #9028

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2cbfbc7
Add initial draft introspection EIP
Brechtpd Nov 9, 2024
0a84cbd
Update EIPS/eip-introspection.md
Brechtpd Nov 28, 2024
1676c94
use EIP number and link to discussions thread
Brechtpd Nov 28, 2024
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59 changes: 59 additions & 0 deletions EIPS/eip-7814.md
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---
eip: 7814
title: Introspection precompiles
description: Introspection precompiles that expose the current block context to the EVM
author: Brecht Devos (@Brechtpd)
discussions-to: https://ethereum-magicians.org/t/eip-7814-introspection-precompiles/21872
status: Draft
type: Standards Track
category: Core
created: 2024-11-09
---

## Abstract

This EIP proposes to add two precompiles that enable introspection of the chain state at arbitrary points within a block in the EVM. Currently, the EVM only has access to the state of previous blocks. No block data is currently exposed to the EVM for the block it's executing in.

## Motivation

The new precompiles aim to enhance introspection capabilities within the EVM, enabling the calculation of the latest chain state offchain at any point in an Ethereum block. This is important to allow general and efficient synchronous composability with L1. Otherwise, to ensure having the latest L1 state, the state would have to be read on L1 and passed in as a separate input. This is expensive and there may be limitations on who can read the state without something like [EIP-2330](https://eips.ethereum.org/EIPS/eip-2330).

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19 | The new precompiles aim to enhance introspection capabilities within the EVM, enabling the calculation of the latest chain state off...
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   = help: see https://ethereum.github.io/eipw/markdown-rel-links/
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kindly address the bot failures


This proposal allows computing the latest state from the state root of the previous block and the transactions that are in the current block. This data can then be passed into any system requiring the latest chain state where the partial block can be re-executed to compute the latest state in a provable way.

## Specification

If `block.number >= TBD` two new precompiled contracts shall be created:
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we now don't add hardfork number/timestamp information in the EIPs

- `TXTRIEROOT` at address `TBD`: This precompile returns the transaction trie root of all transactions in the current block, up to and including the transaction that is currently executing. The tx trie is already calculated for the block header. This EIP just enforces that the trie is constructed incrementally per transaction and exposes the root to the EVM.

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Lists should be surrounded by blank lines [Context: "- `TXTRIEROOT` at address `TBD..."] 

EIPS/eip-7814.md:26 MD032/blanks-around-lists Lists should be surrounded by blank lines [Context: "- `TXTRIEROOT` at address `TBD..."]
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@g11tech g11tech Jan 28, 2025 •
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add a html <-- TODO --> tag to be autoflagged at the review PR stage whereever there is TBD in the EIP

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seems that it would be technically feasible to only compute stateroot till previous tx. kinky confirm that what you wrote is what you intend to propose

- `OPCODECOUNTER` at address `TBD`: This precompile returns a 4 byte uint in big endian encoding representing the total number of opcodes that have been executed for the current transaction up till (and excluding) the call to this precompile.

### Gas Cost

The gas cost for `TXTRIEROOT` and `OPCODECOUNTER` is a fixed fee of `2`.

## Rationale

Simple and efficient access to the latest state of a chain is critical for composability. For synchronous composability, we need to be able to immediately prove all offchain work inside the same block. This makes it impossible to delay the proving to a later block where more information about the current block is available.
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needs some examples where this proposal would be beneficial. rationale is a bit light imo and needs more support and reasoning.


### Gas Price

The precompiles are priced to match similar opcodes in the `W_base` set.

### Precompile

Implementing this feature via precompiles instead of opcodes gives L2s flexibility to decide whether to implement it.
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do you mean precompiles vs system contracts? precomplies are sort of an opcode implementation


## Backwards Compatibility

Further discussion required.

## Test Cases

N/A

## Security Considerations

Needs discussion.
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add html <-- TODO --> tag here and else where (discussion pending) to be autoflagged at review status update stage


## Copyright

Copyright and related rights waived via [CC0](../LICENSE.md).
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