⚠️ DO NOT MERGE: While this improves the performance of the VM, as a side effect, it degrades the performance of the interpreter. So we should only merge/deploy this once we fully switched to the VM. Unfortunately it's not trivial to put these changes behind a feature flag.

Closes #3691

Description

Use the generated static-type based subtyping check for the IsSubType() function (instead of the subtyping check based on sema-type)
Remove usages of MustConvertStaticToSemaType in VM, and rely on static-types.
Migrate all stdlib functions (except for a one or two that strictly needs composite type) to only use static-types (replace the usages of sema-type).

Results:

Vs VM in last released version (`v1.8.3`)

goos: darwin
goarch: arm64
pkg: github.com/onflow/cadence/runtime
cpu: Apple M1 Pro
                                 │ v1.8.3.txt  │             after.txt              │
                                 │   sec/op    │   sec/op     vs base               │
RuntimeFungibleTokenTransferVM-8   291.3µ ± 9%   273.0µ ± 4%  -6.27% (p=0.002 n=10)

                                 │  v1.8.3.txt  │              after.txt              │
                                 │     B/op     │     B/op      vs base               │
RuntimeFungibleTokenTransferVM-8   171.9Ki ± 0%   160.0Ki ± 0%  -6.92% (p=0.000 n=10)

                                 │ v1.8.3.txt  │              after.txt              │
                                 │  allocs/op  │  allocs/op   vs base                │
RuntimeFungibleTokenTransferVM-8   3.082k ± 0%   2.753k ± 0%  -10.67% (p=0.000 n=10)

Vs VM before switching to static-types (master)

goos: darwin
goarch: arm64
pkg: github.com/onflow/cadence/runtime
cpu: Apple M1 Pro
                                 │ before.txt  │             after.txt              │
                                 │   sec/op    │   sec/op     vs base               │
RuntimeFungibleTokenTransferVM-8   285.6µ ± 9%   273.0µ ± 4%  -4.40% (p=0.011 n=10)

                                 │  before.txt  │              after.txt              │
                                 │     B/op     │     B/op      vs base               │
RuntimeFungibleTokenTransferVM-8   170.6Ki ± 0%   160.0Ki ± 0%  -6.21% (p=0.000 n=10)

                                 │ before.txt  │             after.txt              │
                                 │  allocs/op  │  allocs/op   vs base               │
RuntimeFungibleTokenTransferVM-8   3.000k ± 0%   2.753k ± 0%  -8.23% (p=0.000 n=10)

**Note: The master branch also contains some optimizations that was ported over. So the above comparison only includes the improvement we get from switching to static-types only.

Vs Interpreter (master)

goos: darwin
goarch: arm64
pkg: github.com/onflow/cadence/runtime
cpu: Apple M1 Pro
                               │ interpreter.txt │           after.txt           │
                               │     sec/op      │   sec/op     vs base          │
RuntimeFungibleTokenTransfer-8       272.8µ ± 2%   273.0µ ± 4%  ~ (p=0.796 n=10)

                               │ interpreter.txt │              after.txt              │
                               │      B/op       │     B/op      vs base               │
RuntimeFungibleTokenTransfer-8      157.3Ki ± 0%   160.0Ki ± 0%  +1.70% (p=0.000 n=10)

                               │ interpreter.txt │             after.txt              │
                               │    allocs/op    │  allocs/op   vs base               │
RuntimeFungibleTokenTransfer-8       2.980k ± 0%   2.753k ± 0%  -7.62% (p=0.000 n=10)

Future work:

Event emitting still need the sema types (hence the conversion exist). Should try to replace those as well.
Generated subtype check for static-types still converts to sema types in certain cases (for e.g: conformance information is not available in static-types, so need to convert to sema-type to get these information)

[x] Targeted PR against master branch
[x] Linked to Github issue with discussion and accepted design OR link to spec that describes this work
[x] Code follows the standards mentioned here
[x] Updated relevant documentation
[x] Re-reviewed Files changed in the Github PR explorer
[x] Added appropriate labels

Nov 06 '25 21:11 SupunS

Benchstat comparison

Base branch: onflow:master
Base commit: ba29a406ffec57c3db8b4723344413f894fc242a

Results

	old.txt	new.txt
	time/op		delta
pkg:github.com/onflow/cadence/bbq/compiler goos:linux goarch:amd64
CompileFungibleTokenTransferTransaction-4	110µs ± 0%	110µs ± 0%	~	(p=1.000 n=1+1)
CompileTime-4	30.1µs ± 0%	30.9µs ± 0%	~	(p=1.000 n=1+1)
pkg:github.com/onflow/cadence/runtime goos:linux goarch:amd64
ContractFunctionInvocation-4	376µs ± 0%	384µs ± 0%	~	(p=1.000 n=1+1)
pkg:github.com/onflow/cadence/bbq/vm/test goos:linux goarch:amd64
ContractImport-4	179µs ± 0%	176µs ± 0%	~	(p=1.000 n=1+1)
pkg:github.com/onflow/cadence/interpreter goos:linux goarch:amd64
Emit-4	4.37ms ± 0%	5.31ms ± 0%	~	(p=1.000 n=1+1)
pkg:github.com/onflow/cadence/runtime goos:linux goarch:amd64
ExportType/composite_type-4	305ns ± 0%	300ns ± 0%	~	(p=1.000 n=1+1)
ExportType/simple_type-4	66.0ns ± 0%	67.4ns ± 0%	~	(p=1.000 n=1+1)
pkg:github.com/onflow/cadence/bbq/vm/test goos:linux goarch:amd64
FTTransfer-4	115µs ± 0%	104µs ± 0%	~	(p=1.000 n=1+1)
pkg:github.com/onflow/cadence/interpreter goos:linux goarch:amd64
ImperativeFib-4	21.6µs ± 0%	26.3µs ± 0%	~	(p=1.000 n=1+1)
pkg:github.com/onflow/cadence/bbq/vm/test goos:linux goarch:amd64
ImperativeFib-4	14.2µs ± 0%	12.1µs ± 0%	~	(p=1.000 n=1+1)
ImperativeFibNewCompilerNewVM-4	33.8µs ± 0%	32.3µs ± 0%	~	(p=1.000 n=1+1)
ImperativeFibNewVM-4	16.2µs ± 0%	13.6µs ± 0%	~	(p=1.000 n=1+1)
pkg:github.com/onflow/cadence/interpreter goos:linux goarch:amd64
InterpretRecursionFib-4	2.19ms ± 0%	2.65ms ± 0%	~	(p=1.000 n=1+1)
pkg:github.com/onflow/cadence/bbq/vm/test goos:linux goarch:amd64
InterpreterFTTransfer-4	103µs ± 0%	126µs ± 0%	~	(p=1.000 n=1+1)
InterpreterImperativeFib-4	21.0µs ± 0%	25.8µs ± 0%	~	(p=1.000 n=1+1)
InterpreterNewStruct-4	63.0µs ± 0%	71.7µs ± 0%	~	(p=1.000 n=1+1)
MethodCall/concrete_type_method_call-4	27.6µs ± 0%	26.3µs ± 0%	~	(p=1.000 n=1+1)
MethodCall/interface_method_call-4	49.0µs ± 0%	45.2µs ± 0%	~	(p=1.000 n=1+1)
pkg:github.com/onflow/cadence/interpreter goos:linux goarch:amd64
NewInterpreter/new_interpreter-4	910ns ± 0%	857ns ± 0%	~	(p=1.000 n=1+1)
NewInterpreter/new_sub-interpreter-4	326ns ± 0%	325ns ± 0%	~	(p=1.000 n=1+1)
pkg:github.com/onflow/cadence/bbq/vm/test goos:linux goarch:amd64
NewResource-4	78.6µs ± 0%	81.1µs ± 0%	~	(p=1.000 n=1+1)
NewStruct-4	33.5µs ± 0%	31.9µs ± 0%	~	(p=1.000 n=1+1)
NewStructRaw-4	4.14µs ± 0%	3.88µs ± 0%	~	(p=1.000 n=1+1)
RecursionFib-4	821µs ± 0%	691µs ± 0%	~	(p=1.000 n=1+1)
RuntimeFungibleTokenTransfer-4	724µs ± 0%	825µs ± 0%	~	(p=1.000 n=1+1)
pkg:github.com/onflow/cadence/runtime goos:linux goarch:amd64
RuntimeFungibleTokenTransferInterpreter-4	592µs ± 0%	653µs ± 0%	~	(p=1.000 n=1+1)
RuntimeFungibleTokenTransferVM-4	631µs ± 0%	622µs ± 0%	~	(p=1.000 n=1+1)
RuntimeResourceDictionaryValues-4	2.71ms ± 0%	2.77ms ± 0%	~	(p=1.000 n=1+1)
RuntimeResourceTracking-4	12.6ms ± 0%	12.1ms ± 0%	~	(p=1.000 n=1+1)
RuntimeScriptNoop-4	14.8µs ± 0%	14.1µs ± 0%	~	(p=1.000 n=1+1)
RuntimeVMInvokeContractImperativeFib-4	26.8µs ± 0%	23.1µs ± 0%	~	(p=1.000 n=1+1)
pkg:github.com/onflow/cadence/interpreter goos:linux goarch:amd64
ValueIsSubtypeOfSemaType-4	54.6ns ± 0%	54.0ns ± 0%	~	(p=1.000 n=1+1)

	alloc/op		delta
pkg:github.com/onflow/cadence/bbq/compiler goos:linux goarch:amd64
CompileFungibleTokenTransferTransaction-4	79.3kB ± 0%	79.3kB ± 0%	~	(all equal)
CompileTime-4	16.3kB ± 0%	16.3kB ± 0%	~	(all equal)
pkg:github.com/onflow/cadence/runtime goos:linux goarch:amd64
ContractFunctionInvocation-4	152kB ± 0%	155kB ± 0%	~	(p=1.000 n=1+1)
pkg:github.com/onflow/cadence/bbq/vm/test goos:linux goarch:amd64
ContractImport-4	73.9kB ± 0%	73.7kB ± 0%	~	(p=1.000 n=1+1)
pkg:github.com/onflow/cadence/interpreter goos:linux goarch:amd64
Emit-4	1.47MB ± 0%	1.49MB ± 0%	~	(p=1.000 n=1+1)
pkg:github.com/onflow/cadence/runtime goos:linux goarch:amd64
ExportType/composite_type-4	120B ± 0%	120B ± 0%	~	(all equal)
ExportType/simple_type-4	0.00B	0.00B	~	(all equal)
pkg:github.com/onflow/cadence/bbq/vm/test goos:linux goarch:amd64
FTTransfer-4	39.2kB ± 0%	34.3kB ± 0%	~	(p=1.000 n=1+1)
pkg:github.com/onflow/cadence/interpreter goos:linux goarch:amd64
ImperativeFib-4	8.30kB ± 0%	8.30kB ± 0%	~	(all equal)
pkg:github.com/onflow/cadence/bbq/vm/test goos:linux goarch:amd64
ImperativeFib-4	1.94kB ± 0%	1.94kB ± 0%	~	(all equal)
ImperativeFibNewCompilerNewVM-4	21.9kB ± 0%	21.6kB ± 0%	~	(p=1.000 n=1+1)
ImperativeFibNewVM-4	4.70kB ± 0%	4.36kB ± 0%	~	(p=1.000 n=1+1)
pkg:github.com/onflow/cadence/interpreter goos:linux goarch:amd64
InterpretRecursionFib-4	1.19MB ± 0%	1.19MB ± 0%	~	(p=1.000 n=1+1)
pkg:github.com/onflow/cadence/bbq/vm/test goos:linux goarch:amd64
InterpreterFTTransfer-4	39.6kB ± 0%	49.2kB ± 0%	~	(p=1.000 n=1+1)
InterpreterImperativeFib-4	8.29kB ± 0%	8.29kB ± 0%	~	(all equal)
InterpreterNewStruct-4	24.4kB ± 0%	26.2kB ± 0%	~	(p=1.000 n=1+1)
MethodCall/concrete_type_method_call-4	7.00kB ± 0%	6.97kB ± 0%	~	(p=1.000 n=1+1)
MethodCall/interface_method_call-4	14.4kB ± 0%	14.4kB ± 0%	~	(p=1.000 n=1+1)
pkg:github.com/onflow/cadence/interpreter goos:linux goarch:amd64
NewInterpreter/new_interpreter-4	976B ± 0%	976B ± 0%	~	(all equal)
NewInterpreter/new_sub-interpreter-4	232B ± 0%	232B ± 0%	~	(all equal)
pkg:github.com/onflow/cadence/bbq/vm/test goos:linux goarch:amd64
NewResource-4	40.4kB ± 0%	40.1kB ± 0%	~	(p=1.000 n=1+1)
NewStruct-4	10.4kB ± 0%	10.3kB ± 0%	~	(p=1.000 n=1+1)
NewStructRaw-4	2.58kB ± 0%	2.59kB ± 0%	~	(p=1.000 n=1+1)
RecursionFib-4	88.1kB ± 0%	88.1kB ± 0%	~	(all equal)
RuntimeFungibleTokenTransfer-4	234kB ± 0%	266kB ± 0%	~	(p=1.000 n=1+1)
pkg:github.com/onflow/cadence/runtime goos:linux goarch:amd64
RuntimeFungibleTokenTransferInterpreter-4	158kB ± 0%	185kB ± 0%	~	(p=1.000 n=1+1)
RuntimeFungibleTokenTransferVM-4	173kB ± 0%	162kB ± 0%	~	(p=1.000 n=1+1)
RuntimeResourceDictionaryValues-4	1.76MB ± 0%	1.77MB ± 0%	~	(p=1.000 n=1+1)
RuntimeResourceTracking-4	9.27MB ± 0%	9.26MB ± 0%	~	(p=1.000 n=1+1)
RuntimeScriptNoop-4	7.99kB ± 0%	7.98kB ± 0%	~	(p=1.000 n=1+1)
RuntimeVMInvokeContractImperativeFib-4	9.80kB ± 0%	9.32kB ± 0%	~	(p=1.000 n=1+1)
pkg:github.com/onflow/cadence/interpreter goos:linux goarch:amd64
ValueIsSubtypeOfSemaType-4	32.0B ± 0%	32.0B ± 0%	~	(all equal)

	allocs/op		delta
pkg:github.com/onflow/cadence/bbq/compiler goos:linux goarch:amd64
CompileFungibleTokenTransferTransaction-4	424 ± 0%	424 ± 0%	~	(all equal)
CompileTime-4	182 ± 0%	182 ± 0%	~	(all equal)
pkg:github.com/onflow/cadence/runtime goos:linux goarch:amd64
ContractFunctionInvocation-4	2.46k ± 0%	2.53k ± 0%	~	(p=1.000 n=1+1)
pkg:github.com/onflow/cadence/bbq/vm/test goos:linux goarch:amd64
ContractImport-4	938 ± 0%	936 ± 0%	~	(p=1.000 n=1+1)
pkg:github.com/onflow/cadence/interpreter goos:linux goarch:amd64
Emit-4	39.0k ± 0%	40.0k ± 0%	~	(p=1.000 n=1+1)
pkg:github.com/onflow/cadence/runtime goos:linux goarch:amd64
ExportType/composite_type-4	3.00 ± 0%	3.00 ± 0%	~	(all equal)
ExportType/simple_type-4	0.00	0.00	~	(all equal)
pkg:github.com/onflow/cadence/bbq/vm/test goos:linux goarch:amd64
FTTransfer-4	1.00k ± 0%	0.85k ± 0%	~	(p=1.000 n=1+1)
pkg:github.com/onflow/cadence/interpreter goos:linux goarch:amd64
ImperativeFib-4	176 ± 0%	176 ± 0%	~	(all equal)
pkg:github.com/onflow/cadence/bbq/vm/test goos:linux goarch:amd64
ImperativeFib-4	49.0 ± 0%	49.0 ± 0%	~	(all equal)
ImperativeFibNewCompilerNewVM-4	214 ± 0%	212 ± 0%	~	(p=1.000 n=1+1)
ImperativeFibNewVM-4	86.0 ± 0%	84.0 ± 0%	~	(p=1.000 n=1+1)
pkg:github.com/onflow/cadence/interpreter goos:linux goarch:amd64
InterpretRecursionFib-4	17.7k ± 0%	17.7k ± 0%	~	(all equal)
pkg:github.com/onflow/cadence/bbq/vm/test goos:linux goarch:amd64
InterpreterFTTransfer-4	833 ± 0%	1044 ± 0%	~	(p=1.000 n=1+1)
InterpreterImperativeFib-4	175 ± 0%	175 ± 0%	~	(all equal)
InterpreterNewStruct-4	418 ± 0%	448 ± 0%	~	(p=1.000 n=1+1)
MethodCall/concrete_type_method_call-4	135 ± 0%	135 ± 0%	~	(all equal)
MethodCall/interface_method_call-4	285 ± 0%	285 ± 0%	~	(all equal)
pkg:github.com/onflow/cadence/interpreter goos:linux goarch:amd64
NewInterpreter/new_interpreter-4	15.0 ± 0%	15.0 ± 0%	~	(all equal)
NewInterpreter/new_sub-interpreter-4	4.00 ± 0%	4.00 ± 0%	~	(all equal)
pkg:github.com/onflow/cadence/bbq/vm/test goos:linux goarch:amd64
NewResource-4	730 ± 0%	728 ± 0%	~	(p=1.000 n=1+1)
NewStruct-4	219 ± 0%	219 ± 0%	~	(all equal)
NewStructRaw-4	38.0 ± 0%	38.0 ± 0%	~	(all equal)
RecursionFib-4	3.65k ± 0%	3.65k ± 0%	~	(all equal)
RuntimeFungibleTokenTransfer-4	3.99k ± 0%	4.82k ± 0%	~	(p=1.000 n=1+1)
pkg:github.com/onflow/cadence/runtime goos:linux goarch:amd64
RuntimeFungibleTokenTransferInterpreter-4	2.98k ± 0%	3.65k ± 0%	~	(p=1.000 n=1+1)
RuntimeFungibleTokenTransferVM-4	3.04k ± 0%	2.79k ± 0%	~	(p=1.000 n=1+1)
RuntimeResourceDictionaryValues-4	36.7k ± 0%	36.7k ± 0%	~	(p=1.000 n=1+1)
RuntimeResourceTracking-4	159k ± 0%	159k ± 0%	~	(p=1.000 n=1+1)
RuntimeScriptNoop-4	113 ± 0%	113 ± 0%	~	(all equal)
RuntimeVMInvokeContractImperativeFib-4	197 ± 0%	191 ± 0%	~	(p=1.000 n=1+1)
pkg:github.com/onflow/cadence/interpreter goos:linux goarch:amd64
ValueIsSubtypeOfSemaType-4	1.00 ± 0%	1.00 ± 0%	~	(all equal)

Nov 06 '25 21:11 github-actions[bot]

Dependency Review

✅ No vulnerabilities or license issues or OpenSSF Scorecard issues found.

Scanned Files

None

Dec 05 '25 23:12 github-actions[bot]

Codecov Report

:x: Patch coverage is 90.22222% with 44 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
bbq/commons/types.go	58.69%	18 Missing and 1 partial :warning:
interpreter/errors.go	74.07%	6 Missing and 1 partial :warning:
interpreter/interpreter.go	95.74%	4 Missing and 2 partials :warning:
bbq/vm/context.go	86.84%	4 Missing and 1 partial :warning:
interpreter/subtype_check.go	50.00%	2 Missing and 1 partial :warning:
stdlib/account.go	96.42%	0 Missing and 2 partials :warning:
interpreter/value_storage_reference.go	85.71%	0 Missing and 1 partial :warning:
runtime/contract_function_executor.go	0.00%	1 Missing :warning:

:loudspeaker: Thoughts on this report? Let us know!

Dec 05 '25 23:12 codecov[bot]

[...] it degrades the performance of the interpreter.

I missed this before. Is this because in the interpreter we get sema types from the elaboration, and now have to convert them to static types?

Dec 05 '25 23:12 turbolent

[Subtyping Generator] Switch to static-types for runtime subtype checking

Description

Results:

Vs VM in last released version (v1.8.3)

Vs VM before switching to static-types (master)

Vs Interpreter (master)

Future work:

Benchstat comparison

Dependency Review

Scanned Files

Codecov Report

Vs VM in last released version (`v1.8.3`)