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core/vm: optimize opCreate and opCreate2 by not copy memory #32918

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core/vm: optimize opCreate and opCreate2 by not copy memory #32918

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4 changes: 2 additions & 2 deletions core/vm/instructions.go
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Original file line number Diff line number Diff line change
Expand Up @@ -659,7 +659,7 @@ func opCreate(pc *uint64, evm *EVM, scope *ScopeContext) ([]byte, error) {
var (
value = scope.Stack.pop()
offset, size = scope.Stack.pop(), scope.Stack.pop()
input = scope.Memory.GetCopy(offset.Uint64(), size.Uint64())
input = scope.Memory.GetPtr(offset.Uint64(), size.Uint64())
gas = scope.Contract.Gas
)
if evm.chainRules.IsEIP150 {
Expand Down Expand Up @@ -703,7 +703,7 @@ func opCreate2(pc *uint64, evm *EVM, scope *ScopeContext) ([]byte, error) {
endowment = scope.Stack.pop()
offset, size = scope.Stack.pop(), scope.Stack.pop()
salt = scope.Stack.pop()
input = scope.Memory.GetCopy(offset.Uint64(), size.Uint64())
input = scope.Memory.GetPtr(offset.Uint64(), size.Uint64())
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By changing to the GetPtr, the same byte slice will be referenced/used in two call frames: one in the contract creation and another is the caller frame.

It might introduce some unexpected edge cases where the slice mutations from one side affect another side. It feels a very dangerous change to me.

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  1. in ethereum white paper mention that "code is theoretically immutable".
  2. "By changing to the GetPtr, the same byte slice will be referenced/used in two call frames: one in the contract creation and another is the caller frame.

It might introduce some unexpected edge cases where the slice mutations from one side affect another side. "
this is same to opcall. but op call already change to GetPtr!.
3. as in this pr. "I'm not 100% sure we need it, but Create/Create2 holds on to that code, and stores it in a struct for later processing. I didn't consider it safe to change that now", actually, Not only code(input) is stores in struct for later processing, but also the opCall input. GetPtr is call here. and assign to contract.Input here. Which is next next to Code field in contract here.

May ask @holiman and @fjl and @karalabe to help with us.

gas = scope.Contract.Gas
)

Expand Down