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EVM optimizations #2405

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merged 3 commits into from
Dec 2, 2022
Merged

EVM optimizations #2405

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3c924bf
evm: optimize memory extensions (MSTORE/MLOAD related ops)
jochem-brouwer Nov 4, 2022
3871fd1
Merge branch 'master' into optimize-evm
jochem-brouwer Nov 30, 2022
bb10347
Merge remote-tracking branch 'origin/master' into optimize-evm
acolytec3 Dec 2, 2022
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11 changes: 7 additions & 4 deletions packages/evm/src/memory.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -7,6 +7,8 @@ const ceil = (value: number, ceiling: number): number => {
}
}

const CONTAINER_SIZE = 8192

/**
* Memory implements a simple memory model
* for the ethereum virtual machine.
Expand All @@ -30,7 +32,10 @@ export class Memory {
const newSize = ceil(offset + size, 32)
const sizeDiff = newSize - this._store.length
if (sizeDiff > 0) {
this._store = Buffer.concat([this._store, Buffer.alloc(sizeDiff)])
this._store = Buffer.concat([
this._store,
Buffer.alloc(Math.ceil(sizeDiff / CONTAINER_SIZE) * CONTAINER_SIZE),
])
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Ok, just did a quick search ._store.length for the EVM to see if there are any external accesses to memory length where we would have side effects, but this seems not to be the case (apart from some memory-internal tests which can eventually be adopted if needed). 🙂

So this seems like a really clever solution to reduce the buffer allocations drastically along memory extensions! 👍

(still am a bit cautious and wonder though if this might have some side effect(s) somewhere? 🤔

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I agree that we should very carefully examine this. (I also did the same search as you did since I was afraid that there indeed might be external reads to it)

}
}

Expand All @@ -50,9 +55,7 @@ export class Memory {
if (value.length !== size) throw new Error('Invalid value size')
if (offset + size > this._store.length) throw new Error('Value exceeds memory capacity')

for (let i = 0; i < size; i++) {
this._store[offset + i] = value[i]
}
value.copy(this._store, offset)
}

/**
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