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perf(evm): optimize EVMC execute entry path with address-based module cache and instance reuse #366

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perf(evm): optimize EVMC execute entry path with address-based module cache and instance reuse #366

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14 changes: 12 additions & 2 deletions src/evm/interpreter.h
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Original file line number Diff line number Diff line change
Expand Up @@ -10,7 +10,6 @@
#include "intx/intx.hpp"

#include <array>
#include <deque>
#include <vector>

namespace zen {
Expand Down Expand Up @@ -70,7 +69,7 @@ struct EVMFrame {
class InterpreterExecContext {
private:
runtime::EVMInstance *Inst;
std::deque<EVMFrame> FrameStack;
std::vector<EVMFrame> FrameStack;
evmc_status_code Status = EVMC_SUCCESS;
Comment on lines 69 to 73
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Copilot AI Feb 28, 2026

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Changing FrameStack from std::deque to std::vector can invalidate pointers/references to existing frames on growth (reallocation). This is unsafe here because allocTopFrame() stores pointers to Frame.Msg in EVMInstance::MessageStack and interpreter code keeps EVMFrame* (e.g., parent frame) across nested calls; a reallocation would turn those pointers into dangling pointers and can cause memory corruption. Use a container with stable addresses (e.g., keep std::deque), or reserve a hard upper bound up-front and enforce max depth so FrameStack never reallocates, or store frames/messages in separately allocated stable storage.

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std::vector<uint8_t> ReturnData;
evmc::Result ExeResult;
Expand All @@ -80,6 +79,17 @@ class InterpreterExecContext {

InterpreterExecContext(runtime::EVMInstance *Inst) : Inst(Inst) {}

/// Reset state for reuse across calls. Keeps allocated capacity to avoid
/// re-allocating the ~32KB EVMFrame on every call.
void resetForNewCall(runtime::EVMInstance *NewInst) {
Inst = NewInst;
FrameStack.clear(); // keeps vector capacity
Status = EVMC_SUCCESS;
ReturnData.clear(); // keeps vector capacity
IsJump = false;
ExeResult = evmc::Result{EVMC_SUCCESS, 0, 0};
}
Comment on lines +82 to +91
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Copilot AI Feb 28, 2026

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resetForNewCall() intends to preserve ReturnData/FrameStack capacity, but many interpreter paths set return data via setReturnData(std::vector<uint8_t>()) / move-assigning a new vector, which typically discards the existing buffer and defeats cross-call capacity caching. To realize the intended optimization, consider switching those "clear return data" sites to a clear() on the existing buffer (or add a dedicated clearReturnData() API) instead of replacing the vector instance.

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EVMFrame *allocTopFrame(evmc_message *Msg);
void freeBackFrame();

Expand Down
36 changes: 36 additions & 0 deletions src/runtime/evm_instance.cpp
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Expand Up @@ -60,6 +60,42 @@ EVMInstanceUniquePtr EVMInstance::newEVMInstance(Isolation &Iso,

EVMInstance::~EVMInstance() {}

void EVMInstance::resetForNewCall(evmc_revision NewRev) {
// Reset gas accounting
Gas = 0;
GasRefund = 0;
Rev = NewRev;
InstanceExitCode = 0;
Err = common::ErrorCode::NoError;

// Reset message stack (clear but keep capacity)
CurrentMessage = nullptr;
MessageStack.clear();
GasRefundStack.clear();

// Reset memory: keep the 16MB allocation, just reset the size
MemoryBase = nullptr;
MemorySize = 0;
// Don't release Memory - reuse the allocation on next pushMessage()
MemoryStack.clear();

// Reset output
ReturnData.clear();
ExeResult = evmc::Result{EVMC_SUCCESS, 0, 0};

// Reset execution cache: clear() keeps allocated bucket arrays,
// avoiding repeated alloc/free of unordered_map internals.
InstanceExecutionCache.BlockHashes.clear();
InstanceExecutionCache.BlobHashes.clear();
InstanceExecutionCache.CalldataLoads.clear();
InstanceExecutionCache.ExtcodeHashes.clear();
InstanceExecutionCache.Keccak256Results.clear();
InstanceExecutionCache.TxContextCached = false;

// Reset JIT stack
EVMStackSize = 0;
}

void EVMInstance::setGas(uint64_t NewGas) { Gas = NewGas; }

void EVMInstance::pushMessage(evmc_message *Msg) {
Expand Down
4 changes: 4 additions & 0 deletions src/runtime/evm_instance.h
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Expand Up @@ -101,6 +101,10 @@ class EVMInstance final : public RuntimeObject<EVMInstance> {
void setError(const Error &E) { Err = E; }
void clearError() { Err = ErrorCode::NoError; }

/// Reset instance state for reuse in interpreter mode.
/// Avoids the cost of destroy + recreate on every EVMC execute() call.
Comment on lines +104 to +105
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Copilot AI Feb 28, 2026

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The comment says resetForNewCall() is for reuse in interpreter mode, but the new dt_evmc_vm path calls it for multipass/JIT executions as well (getOrCreateInstance()). Please update the comment to reflect that the reset is used for general cross-call instance reuse across modes, or restrict usage if it truly must be interpreter-only.

Suggested change
/// Reset instance state for reuse in interpreter mode.
/// Avoids the cost of destroy + recreate on every EVMC execute() call.
/// Reset instance state for reuse across EVMC execute() calls, regardless
/// of execution mode (interpreter, multipass, or JIT). This avoids the cost
/// of destroying and recreating the instance for each call.

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void resetForNewCall(evmc_revision NewRev);

// can only called by hostapi directly
// setExceptionByHostapi must be inline to capture the hostapi's frame
// pointer
Expand Down
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