core/vm: Idea for enabling an experimental evm#34645
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kevaundray wants to merge 6 commits intoethereum:masterfrom
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core/vm: Idea for enabling an experimental evm#34645kevaundray wants to merge 6 commits intoethereum:masterfrom
kevaundray wants to merge 6 commits intoethereum:masterfrom
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- Move common charge gas functionality into shared function - add flag for triggering the experimental interpreter
kevaundray
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Apr 3, 2026
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| // All ops with a dynamic memory usage also has a dynamic gas cost. | ||
| var operation *operation | ||
| var memorySize uint64 | ||
| if operation.dynamicGas != nil { | ||
| // calculate the new memory size and expand the memory to fit | ||
| // the operation | ||
| // Memory check needs to be done prior to evaluating the dynamic gas portion, | ||
| // to detect calculation overflows | ||
| if operation.memorySize != nil { | ||
| memSize, overflow := operation.memorySize(stack) | ||
| if overflow { | ||
| return nil, ErrGasUintOverflow | ||
| } | ||
| // memory is expanded in words of 32 bytes. Gas | ||
| // is also calculated in words. | ||
| if memorySize, overflow = math.SafeMul(toWordSize(memSize), 32); overflow { | ||
| return nil, ErrGasUintOverflow | ||
| } | ||
| } | ||
| // Consume the gas and return an error if not enough gas is available. | ||
| // cost is explicitly set so that the capture state defer method can get the proper cost | ||
| var dynamicCost uint64 | ||
| dynamicCost, err = operation.dynamicGas(evm, contract, stack, mem, memorySize) | ||
| cost += dynamicCost // for tracing | ||
| if err != nil { |
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This is the biggest diff on existing code. This functionality is used in the experimental EVM so I pulled it out into chargeGasOp function to avoid code duplication
kevaundray
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Apr 3, 2026
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| // - all inlined opcodes only touch the stack, so executing a few extra ops | ||
| // before detecting OOG has no observable side effects. |
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This optimization in spirit, just says; we will execute and group "basic blocks" wrt their gas cost
kevaundray
commented
Apr 3, 2026
| contract.Gas -= gasUsed | ||
| return nil, &ErrStackUnderflow{stackLen: stack.len(), required: 2} | ||
| } | ||
| x, y := stack.pop(), stack.peek() |
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Its possible to remove these methods, and use the raw stack slice. It saves about 7-8.5% but makes the code harder to read
kevaundray
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Apr 3, 2026
| continue // skip pc++ | ||
| } | ||
| // Flush gas and fall back to normal dispatch | ||
| default: |
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Here we just fall back to the normal interpreter for everything else
kevaundray
changed the title
kevaundray
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Apr 3, 2026
| x, y := stack.pop(), stack.peek() | ||
| y.Sub(&x, y) | ||
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||
| case MUL: |
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sidenote: A different way to have done this, would have been to use go generate
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This is a simple idea for enabling an experimental EVM that can be developed/optimized alongside the normal EVM.
Currently it only optimizes, commonly used compute opcodes using a switch dispatch (the savings are about 50%), and then fallsback to the normal interpreter for everything else. None of the optimization techniques here are new.