perf(evm): add soft-fallback opcode table for const memory precheck#484
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perf(evm): add soft-fallback opcode table for const memory precheck#484ys8888john wants to merge 2 commits into
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⚡ Performance Regression Check Results✅ Performance Check Passed (interpreter)Performance Benchmark Results (threshold: 25%)
Summary: 194 benchmarks, 0 regressions ✅ Performance Check Passed (multipass)Performance Benchmark Results (threshold: 25%)
Summary: 194 benchmarks, 1 regressions |
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Pull request overview
This PR extends the EVM bytecode visitor’s const direct-memory precheck analysis by adding a 256-entry “opaque” opcode stack-effect table, allowing more non-memory-mutating opcodes to be simulated (instead of immediately rejecting the precheck plan). It also changes MSIZE handling to conservatively bail out to avoid semantic mismatches when memory-expansion is pre-applied.
Changes:
- Add
PrecheckOpaqueStackEffect+buildPrecheckOpaqueStackEffectTable()to model stack deltas for additional opcodes in the const-precheck simulator’s fallback path. - Update const-precheck simulation
default:handling to use the new table rather than unconditionally bailing. - Change
OP_MSIZEhandling in const-precheck simulation to hard-bail to avoid incorrect observed memory size.
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| static constexpr auto OpaqueEffects = | ||
| buildPrecheckOpaqueStackEffectTable(); | ||
| const PrecheckOpaqueStackEffect &Eff = | ||
| OpaqueEffects[static_cast<uint8_t>(Opcode)]; | ||
| if (Eff.Pops == kPrecheckBailSentinel) { | ||
| return {}; | ||
| } |
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| case OP_MSIZE: | ||
| SimStack.push_back(makeUnknownConstU64()); | ||
| break; | ||
| default: | ||
| // MSIZE observes the precise memory size at the moment it executes. | ||
| // Hoisting expandMemoryIR to the BB entry would expand memory ahead | ||
| // of MSIZE and pollute its observed value, breaking EVM semantics | ||
| // (state root mismatch in vmIOandFlowOperations.msize). Hard-bail. | ||
| return {}; |
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