core/vm: reuse Memory instances #30137 #33056

[gzliudan]

Proposed changes

Ref:

• core/vm: reuse Memory instances ethereum/go-ethereum#30137
• core/vm: refactor memory resize ethereum/go-ethereum#33056

Types of changes

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• Bugfix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation Update (if none of the other choices apply)
• Regular KTLO or any of the maintaince work. e.g code style
• CICD Improvement

Impacted Components

Which part of the codebase this PR will touch base on,

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• Consensus
• Account
• Network
• Geth
• Smart Contract
• External components
• Not sure (Please specify below)

Checklist

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• This PR has sufficient test coverage (unit/integration test) OR I have provided reason in the PR description for not having test coverage
• Provide an end-to-end test plan in the PR description on how to manually test it on the devnet/testnet.
• Tested the backwards compatibility.
• Tested with XDC nodes running this version co-exist with those running the previous version.
• Relevant documentation has been updated as part of this PR
• N/A

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[Copilot]

Pull request overview

This pull request implements memory pooling for EVM Memory instances to improve performance by reducing allocations. The changes introduce a sync.Pool to reuse Memory objects, add a Free() method to return memory to the pool, and critically fix opReturn/opRevert operations to copy data instead of returning pointers to prevent use-after-free bugs.

Changes:

• Introduced sync.Pool for Memory instances with smart pooling (only buffers ≤16KB)
• Changed GetCopy/GetPtr signatures from int64 to uint64 for better type semantics
• Fixed opReturn and opRevert to use GetCopy instead of GetPtr to prevent use-after-free when memory is freed
• Added benchmark test for RETURN operation with various memory sizes

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated no comments.

File	Description
core/vm/memory.go	Implements memory pooling with sync.Pool, adds Free() method, changes signatures to uint64, removes bounds checks (safe due to guaranteed resize)
core/vm/interpreter.go	Adds mem.Free() call in defer to return memory to pool after execution
core/vm/instructions.go	Updates all call sites for new uint64 signatures, critically changes opReturn/opRevert to use GetCopy to prevent use-after-free
core/vm/runtime/runtime_test.go	Adds BenchmarkEVM_RETURN to measure performance impact of memory pooling with various return sizes

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