Increase Stylus smart contract size limit via merge-on-activate #4193

tsahee · 2026-01-28T00:04:54Z

let's use uint8 and only take 1.
255 fragments should be enough, and we're very close to the 32byte limit.

Ok here is the PR for that #4285

tsahee · 2026-01-28T00:09:34Z

That's a style question, but I don't like this function name. It's visible/theoretically callable from the entire module and "handle" doesn't mean anything for that context. Suggest something like "getWasmFromClassicStylus" or something similar.

tsahee · 2026-01-28T00:17:50Z

-Original file line number
+Diff line change
@@ Expand Up @@
     	status := C.brotli_compress(inbuf, outbuf, C.Dictionary(dictionary), u32(level))
     	if status != C.BrotliStatus_Success {
-    		return nil, fmt.Errorf("failed decompression: %d", status)
+    		return nil, fmt.Errorf("failed compression: %d", status)
     	}
     	output = output[:*outbuf.len]
     	return output, nil
@@ Expand Down @@

-Original file line number
+Diff line change
@@ Expand Up / @@ -462,8 +462,13 @@ func (state *ArbosState) UpgradeArbosVersion( @@
     		case 52, 53, 54, 55, 56, 57, 58, 59:
     			// these versions are left to Orbit chains for custom upgrades.
-    		case params.ArbosVersion_TransactionFiltering:
-    			// Once the final ArbOS version is locked in, this can be moved to that numeric version.
+    		case params.ArbosVersion_60:
+    			// Changes for ArbosVersion_StylusContractLimit
+    			p, err := state.Programs().Params()
+    			ensure(err)
+    			ensure(p.UpgradeToArbosVersion(nextArbosVersion))
+    			ensure(p.Save())
+    			// Changes for ArbosVersion_TransactionFiltering
     			ensure(addressSet.Initialize(state.backingStorage.OpenSubStorage(transactionFiltererSubspace)))
     		default:
@@ Expand Down @@

-Original file line number
+Diff line change
@@ Expand Up / @@ -262,7 +262,7 @@ func activateProgramInternal( @@
     }
     // getCompiledProgram gets compiled wasm for all targets and recompiles missing ones.
-    func getCompiledProgram(statedb vm.StateDB, moduleHash common.Hash, addressForLogging common.Address, code []byte, codehash common.Hash, maxWasmSize uint32, pagelimit uint16, time uint64, debugMode bool, program Program, runCtx *core.MessageRunContext) (map[rawdb.WasmTarget][]byte, error) {
+    func getCompiledProgram(statedb vm.StateDB, moduleHash common.Hash, addressForLogging common.Address, code []byte, codehash common.Hash, params *StylusParams, time uint64, debugMode bool, program Program, runCtx *core.MessageRunContext) (map[rawdb.WasmTarget][]byte, error) {
     	targets := runCtx.WasmTargets()
     	// even though we need only asm for local target, make sure that all configured targets are available as they are needed during multi-target recording of a program call
     	asmMap, missingTargets, err := statedb.ActivatedAsmMap(targets, moduleHash)
@@ Expand All @@
     	}
     	// addressForLogging may be empty or may not correspond to the code, so we need to be careful to use the code passed in separately
-    	wasm, err := getWasmFromContractCode(code, maxWasmSize)
+    	wasm, err := getWasmFromContractCode(statedb, code, params, false)
     	if err != nil {
     		log.Error("Failed to reactivate program: getWasm", "address", addressForLogging, "expected moduleHash", moduleHash, "err", err)
     		return nil, fmt.Errorf("failed to reactivate program address: %v err: %w", addressForLogging, err)
@@ Expand All @@
     	// we know program is activated, so it must be in correct version and not use too much memory
     	moduleActivationMandatory := false
     	// compile only missing targets
-    	info, newlyBuilt, err := activateProgramInternal(addressForLogging, codehash, wasm, pagelimit, program.version, zeroArbosVersion, debugMode, &zeroGas, missingTargets, moduleActivationMandatory)
+    	info, newlyBuilt, err := activateProgramInternal(addressForLogging, codehash, wasm, params.PageLimit, program.version, zeroArbosVersion, debugMode, &zeroGas, missingTargets, moduleActivationMandatory)
     	if err != nil {
     		log.Error("failed to reactivate program", "address", addressForLogging, "expected moduleHash", moduleHash, "err", err)
     		return nil, fmt.Errorf("failed to reactivate program address: %v err: %w", addressForLogging, err)
@@ Expand Down Expand Up @@
     	return asmMap, nil
     }
-    func handleProgramPrepare(statedb vm.StateDB, moduleHash common.Hash, addressForLogging common.Address, code []byte, codehash common.Hash, maxWasmSize uint32, pagelimit uint16, time uint64, debugMode bool, program Program, runCtx *core.MessageRunContext) []byte {
-    	asmMap, err := getCompiledProgram(statedb, moduleHash, addressForLogging, code, codehash, maxWasmSize, pagelimit, time, debugMode, program, runCtx)
+    func handleProgramPrepare(statedb vm.StateDB, moduleHash common.Hash, addressForLogging common.Address, code []byte, codehash common.Hash, params *StylusParams, time uint64, debugMode bool, program Program, runCtx *core.MessageRunContext) []byte {
+    	asmMap, err := getCompiledProgram(statedb, moduleHash, addressForLogging, code, codehash, params, time, debugMode, program, runCtx)
     	var ok bool
     	var localAsm []byte
     	if asmMap != nil {
@@ Expand Down Expand Up @@
     func cacheProgram(db vm.StateDB, module common.Hash, program Program, addressForLogging common.Address, code []byte, codehash common.Hash, params *StylusParams, debug bool, time uint64, runCtx *core.MessageRunContext) {
     	if runCtx.IsCommitMode() {
     		// address is only used for logging
-    		asmMap, err := getCompiledProgram(db, module, addressForLogging, code, codehash, params.MaxWasmSize, params.PageLimit, time, debug, program, runCtx)
+    		asmMap, err := getCompiledProgram(db, module, addressForLogging, code, codehash, params, time, debug, program, runCtx)
     		var ok bool
     		var localAsm []byte
     		if asmMap != nil {
@@ Expand Down @@

-Original file line number
+Diff line change
@@ Expand Up / @@ -24,13 +24,14 @@ const InitialPageGas = 1000 // linear cost per allocation. @@
     const initialPageRamp = 620674314     // targets 8MB costing 32 million gas, minus the linear term.
     const initialPageLimit = 128          // reject wasms with memories larger than 8MB.
     const initialInkPrice = 10000         // 1 evm gas buys 10k ink.
-    const initialMinInitGas = 72          // charge 72 * 128 = 9216 gas.
-    const initialMinCachedGas = 11        // charge 11 *  32 = 352 gas.
-    const initialInitCostScalar = 50      // scale costs 1:1 (100%)
-    const initialCachedCostScalar = 50    // scale costs 1:1 (100%)
-    const initialExpiryDays = 365         // deactivate after 1 year.
-    const initialKeepaliveDays = 31       // wait a month before allowing reactivation.
-    const initialRecentCacheSize = 32     // cache the 32 most recent programs.
+    const initialMaxFragmentCount = 2
+    const initialMinInitGas = 72       // charge 72 * 128 = 9216 gas.
+    const initialMinCachedGas = 11     // charge 11 *  32 = 352 gas.
+    const initialInitCostScalar = 50   // scale costs 1:1 (100%)
+    const initialCachedCostScalar = 50 // scale costs 1:1 (100%)
+    const initialExpiryDays = 365      // deactivate after 1 year.
+    const initialKeepaliveDays = 31    // wait a month before allowing reactivation.
+    const initialRecentCacheSize = 32  // cache the 32 most recent programs.
     const v2MinInitGas = 69 // charge 69 * 128 = 8832 gas (minCachedGas will also be charged in v2).
@@ Expand Down Expand Up / @@ -60,6 +61,7 @@ type StylusParams struct { @@
     	KeepaliveDays    uint16
     	BlockCacheSize   uint16
     	MaxWasmSize      uint32
+    	MaxFragmentCount uint16
     }
     // Provides a view of the Stylus parameters. Call Save() to persist.
@@ Expand Down Expand Up / @@ -110,6 +112,11 @@ func (p Programs) Params() (*StylusParams, error) { @@
     	} else {
     		stylusParams.MaxWasmSize = initialMaxWasmSize
     	}
+    	if p.ArbosVersion >= params.ArbosVersion_StylusContractLimit {
+    		stylusParams.MaxFragmentCount = arbmath.BytesToUint16(take(2))
+    	} else {
+    		stylusParams.MaxFragmentCount = 0
+    	}
     	return stylusParams, nil
     }
@@ Expand Down Expand Up / @@ -139,6 +146,9 @@ func (p *StylusParams) Save() error { @@
     	if p.arbosVersion >= params.ArbosVersion_40 {
     		data = append(data, arbmath.Uint32ToBytes(p.MaxWasmSize)...)
     	}
+    	if p.arbosVersion >= params.ArbosVersion_StylusContractLimit {
+    		data = append(data, arbmath.Uint16ToBytes(p.MaxFragmentCount)...)
+    	}
     	slot := uint64(0)
     	for len(data) != 0 {
@@ Expand Down Expand Up @@
     }
     func (p *StylusParams) UpgradeToArbosVersion(newArbosVersion uint64) error {
-    	if newArbosVersion == params.ArbosVersion_50 {
-    		if p.arbosVersion >= params.ArbosVersion_50 {
-    			return fmt.Errorf("unexpected arbosVersion upgrade to %d from %d", newArbosVersion, p.arbosVersion)
-    		}
+    	if p.arbosVersion >= newArbosVersion {
+    		return fmt.Errorf("unexpected arbosVersion upgrade to %d from %d", newArbosVersion, p.arbosVersion)
+    	}
+    	switch newArbosVersion {
+    	case params.ArbosVersion_50:
     		if p.MaxStackDepth > arbOS50MaxWasmSize {
     			p.MaxStackDepth = arbOS50MaxWasmSize
     		}
-    	}
-    	if newArbosVersion == params.ArbosVersion_40 {
-    		if p.arbosVersion >= params.ArbosVersion_40 {
-    			return fmt.Errorf("unexpected arbosVersion upgrade to %d from %d", newArbosVersion, p.arbosVersion)
-    		}
+    	case params.ArbosVersion_40:
     		if p.Version != 2 {
     			return fmt.Errorf("unexpected arbosVersion upgrade to %d while stylus version %d", newArbosVersion, p.Version)
     		}
     		p.MaxWasmSize = initialMaxWasmSize
+    	case params.ArbosVersion_StylusContractLimit:
+    		p.MaxFragmentCount = initialMaxFragmentCount
     	}
     	p.arbosVersion = newArbosVersion
     	return nil
     }
@@ Expand All @@
     	if arbosVersion >= params.ArbosVersion_40 {
     		stylusParams.MaxWasmSize = initialMaxWasmSize
     	}
+    	if arbosVersion >= params.ArbosVersion_StylusContractLimit {
+    		stylusParams.MaxFragmentCount = initialMaxFragmentCount
+    	}
     	_ = stylusParams.Save()
     }

-Original file line number
+Diff line change
@@ Expand Up @@
     		// already activated and up to date
     		return 0, codeHash, common.Hash{}, nil, false, ProgramUpToDateError()
     	}
-    	wasm, err := getWasm(statedb, address, params.MaxWasmSize)
+    	wasm, err := getWasm(statedb, address, params)
     	if err != nil {
     		return 0, codeHash, common.Hash{}, nil, false, err
     	}
@@ Expand Down Expand Up / @@ -224,7 +224,7 @@ func (p Programs) CallProgram( @@
     	statedb.AddStylusPages(program.footprint)
     	defer statedb.SetStylusPagesOpen(open)
-    	localAsm := handleProgramPrepare(statedb, moduleHash, contract.Address(), contract.Code, contract.CodeHash, params.MaxWasmSize, params.PageLimit, evm.Context.Time, debugMode, program, runCtx)
+    	localAsm := handleProgramPrepare(statedb, moduleHash, contract.Address(), contract.Code, contract.CodeHash, params, evm.Context.Time, debugMode, program, runCtx)
     	evmData := &EvmData{
     		arbosVersion:    evm.Context.ArbOSVersion,
@@ Expand Down Expand Up / @@ -298,30 +298,104 @@ func evmMemoryCost(size uint64) uint64 { @@
     	return linearCost + squareCost
     }
-    func getWasm(statedb vm.StateDB, program common.Address, maxWasmSize uint32) ([]byte, error) {
+    func getWasm(statedb vm.StateDB, program common.Address, params *StylusParams) ([]byte, error) {
     	prefixedWasm := statedb.GetCode(program)
-    	return getWasmFromContractCode(prefixedWasm, maxWasmSize)
+    	return getWasmFromContractCode(statedb, prefixedWasm, params, true)
     }
-    func getWasmFromContractCode(prefixedWasm []byte, maxWasmSize uint32) ([]byte, error) {
-    	if prefixedWasm == nil {
+    func getWasmFromContractCode(statedb vm.StateDB, prefixedWasm []byte, params *StylusParams, isActivation bool) ([]byte, error) {
+    	if len(prefixedWasm) == 0 {
     		return nil, ProgramNotWasmError()
     	}
-    	wasm, dictByte, err := state.StripStylusPrefix(prefixedWasm)
+    	if state.IsStylusClassicProgramPrefix(prefixedWasm) {
+    		return handleClassicStylus(prefixedWasm, params.MaxWasmSize)
+    	}
+    	if params.arbosVersion >= gethParams.ArbosVersion_StylusContractLimit {
+    		if state.IsStylusRootProgramPrefix(prefixedWasm) {
+    			return handleRootStylus(statedb, prefixedWasm, params.MaxWasmSize, params.MaxFragmentCount, isActivation)
+    		}
+    		if state.IsStylusFragmentPrefix(prefixedWasm) {
+    			return nil, errors.New("fragmented stylus programs cannot be activated directly; activate the root program instead")
+    		}
+    	}
+    	return nil, ProgramNotWasmError()
+    }
+    func handleClassicStylus(data []byte, maxSize uint32) ([]byte, error) {
+    	wasm, dictByte, err := state.StripStylusPrefix(data)
+    	if err != nil {
+    		return nil, err
+    	}
+    	dict, err := getStylusCompressionDict(dictByte)
+    	if err != nil {
+    		return nil, err
+    	}
+    	return arbcompress.DecompressWithDictionary(wasm, int(maxSize), dict)
+    }
+    func handleRootStylus(statedb vm.StateDB, data []byte, maxSize uint32, maxFragments uint16, isActivation bool) ([]byte, error) {
+    	root, err := state.NewStylusRoot(data)
+    	if err != nil {
+    		return nil, err
+    	}
+    	if isActivation {
+    		if root.DecompressedLength > maxSize {
+    			return nil, fmt.Errorf("invalid wasm: decompressedLength %d is greater then MaxWasmSize %d", root.DecompressedLength, maxSize)
+    		}
+    		if len(root.Addresses) > int(maxFragments) {
+    			return nil, fmt.Errorf("invalid wasm: fragment count exceeds limit of %d", maxFragments)
+    		}
+    	}
+    	if len(root.Addresses) == 0 {
+    		return nil, fmt.Errorf("invalid wasm: fragment count cannot be zero")
+    	}
+    	var compressedWasm []byte
+    	for _, addr := range root.Addresses {
+    		fragCode := statedb.GetCode(addr)
+    		payload, err := state.StripStylusFragmentPrefix(fragCode)
+    		if err != nil {
+    			return nil, err
+    		}
+    		compressedWasm = append(compressedWasm, payload...)
+    	}
+    	dict, err := getStylusCompressionDict(root.DictionaryType)
     	if err != nil {
     		return nil, err
     	}
-    	var dict arbcompress.Dictionary
-    	switch dictByte {
+    	wasm, err := arbcompress.DecompressWithDictionary(compressedWasm, int(root.DecompressedLength), dict)
+    	if err != nil {
+    		return nil, err
+    	}
+    	if len(wasm) != int(root.DecompressedLength) {
+    		return nil, fmt.Errorf("invalid wasm: decompressed length %d does not match expected length %d", len(wasm), root.DecompressedLength)
+    	}
+    	return wasm, nil
+    }
+    func getStylusCompressionDict(id byte) (arbcompress.Dictionary, error) {
+    	switch id {
     	case 0:
-    		dict = arbcompress.EmptyDictionary
+    		return arbcompress.EmptyDictionary, nil
     	case 1:
-    		dict = arbcompress.StylusProgramDictionary
+    		return arbcompress.StylusProgramDictionary, nil
     	default:
-    		return nil, fmt.Errorf("unsupported dictionary %v", dictByte)
+    		return 0, fmt.Errorf("unsupported dictionary type: %d", id)
     	}
-    	return arbcompress.DecompressWithDictionary(wasm, int(maxWasmSize), dict)
     }
     // Gets a program entry, which may be expired or not yet activated.
@@ Expand Down @@

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Increase Stylus smart contract size limit via merge-on-activate #4193

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tsahee Jan 28, 2026

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-Original file line number
+Diff line change
@@ Expand Up / @@ -156,7 +156,7 @@ func startProgram(module uint32) uint32 @@
     //go:wasmimport programs send_response
     func sendResponse(req_id uint32) uint32
-    func handleProgramPrepare(statedb vm.StateDB, moduleHash common.Hash, addressForLogging common.Address, code []byte, codehash common.Hash, maxWasmSize uint32, pagelimit uint16, time uint64, debugMode bool, program Program, runCtx *core.MessageRunContext) []byte {
+    func handleProgramPrepare(statedb vm.StateDB, moduleHash common.Hash, addressForLogging common.Address, code []byte, codehash common.Hash, params *StylusParams, time uint64, debugMode bool, program Program, runCtx *core.MessageRunContext) []byte {
     	requiresPrepare := programRequiresPrepare(unsafe.Pointer(&moduleHash[0]))
     	if requiresPrepare != 0 {
     		var debugInt uint32
@@ Expand All @@
     			unsafe.Pointer(&code),
     			codeSize,
     			unsafe.Pointer(&codehash),
-    			maxWasmSize,
-    			uint32(pagelimit),
+    			params.MaxWasmSize,
+    			uint32(params.PageLimit),
     			time,
     			debugInt,
     			unsafe.Pointer(&program),
@@ Expand Down @@

Original file line number	Diff line number	Diff line change
		@@ -0,0 +1,2 @@
		### Added
		- Increase Stylus smart contract size limit via merge-on-activate

+1 −1		ArbAddressTable.sol
+2 −1		ArbInfo.sol
+1 −1		LICENSE.md

-Original file line number
+Diff line change
@@ Expand Up @@
     		codeHashBytes := bytes.TrimPrefix(iter.Key(), rawdb.CodePrefix)
     		codeHash := common.BytesToHash(codeHashBytes)
     		code := iter.Value()
-    		if state.IsStylusProgram(code) {
+    		if state.IsStylusDeployableProgramPrefix(code) {
     			if err := programs.SaveActiveProgramToWasmStore(stateDB, codeHash, code, latestHeader.Time, l2Blockchain.Config().DebugMode(), rebuildingStartHeader.Time, targets); err != nil {
     				return fmt.Errorf("error while rebuilding of wasm store, aborting rebuilding: %w", err)
     			}
@@ Expand Down @@

+95 −5		core/state/statedb_arbitrum.go
+1 −1		core/vm/evm.go
+94 −0		core/vm/evm_arbitrum_test.go
+1 −1		core/vm/instructions.go
+73 −0		core/vm/instructions_test.go
+1 −1		core/vm/interpreter.go
+1 −0		params/config_arbitrum.go

-Original file line number
+Diff line change
@@ Expand Up / @@ -603,5 +603,10 @@ func (con ArbOwner) SetMultiGasPricingConstraints( @@
     }
     func (con ArbOwner) SetMaxStylusContractFragments(c ctx, evm mech, maxFragments uint16) error {
-    	return errors.New("SetMaxStylusContractFragments is not implemented yet")
+    	params, err := c.State.Programs().Params()
+    	if err != nil {
+    		return err
+    	}
+    	params.MaxFragmentCount = maxFragments
+    	return params.Save()
     }

-Original file line number
+Diff line change
@@ Expand Up / @@ -4,8 +4,6 @@ @@
     package precompiles
     import (
-    	"errors"
     	"github.com/ethereum/go-ethereum/common"
     	"github.com/ethereum/go-ethereum/params"
     )
@@ Expand Down Expand Up @@
     }
     func (con ArbOwnerPublic) GetMaxStylusContractFragments(c ctx, evm mech) (uint16, error) {
-    	return 0, errors.New("GetMaxStylusContractFragments is not implemented yet")
+    	params, err := c.State.Programs().Params()
+    	if err != nil {
+    		return 0, err
+    	}
+    	return params.MaxFragmentCount, nil
     }

-Original file line number
+Diff line change
@@ Expand Up / @@ -561,7 +561,7 @@ func Precompiles() map[addr]ArbosPrecompile { @@
     	ArbOwnerPublic.methodsByName["IsNativeTokenOwner"].arbosVersion = params.ArbosVersion_41
     	ArbOwnerPublic.methodsByName["GetAllNativeTokenOwners"].arbosVersion = params.ArbosVersion_41
     	ArbOwnerPublic.methodsByName["GetParentGasFloorPerToken"].arbosVersion = params.ArbosVersion_50
-    	ArbOwnerPublic.methodsByName["GetMaxStylusContractFragments"].arbosVersion = params.ArbosVersion_60
+    	ArbOwnerPublic.methodsByName["GetMaxStylusContractFragments"].arbosVersion = params.ArbosVersion_StylusContractLimit
     	ArbWasmImpl := &ArbWasm{Address: types.ArbWasmAddress}
     	ArbWasm := insert(MakePrecompile(precompilesgen.ArbWasmMetaData, ArbWasmImpl))
@@ Expand Down Expand Up / @@ -656,6 +656,7 @@ func Precompiles() map[addr]ArbosPrecompile { @@
     	ArbOwner.methodsByName["GetAllNativeTokenOwners"].arbosVersion = params.ArbosVersion_41
     	ArbOwner.methodsByName["SetParentGasFloorPerToken"].arbosVersion = params.ArbosVersion_50
     	ArbOwner.methodsByName["SetMaxBlockGasLimit"].arbosVersion = params.ArbosVersion_50
+    	ArbOwner.methodsByName["SetMaxStylusContractFragments"].arbosVersion = params.ArbosVersion_StylusContractLimit
     	ArbOwner.methodsByName["AddTransactionFilterer"].arbosVersion = params.ArbosVersion_TransactionFiltering
     	ArbOwner.methodsByName["RemoveTransactionFilterer"].arbosVersion = params.ArbosVersion_TransactionFiltering
@@ Expand Down @@

Increase Stylus smart contract size limit via merge-on-activate #4193

Increase Stylus smart contract size limit via merge-on-activate #4193

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