cfb11f352a
This adds `RuntimeConfig.WithFeatureMutableGlobal(enabled bool)`, which allows disabling of mutable globals. When disabled, any attempt to add a mutable global, either explicitly or implicitly via decoding wasm will fail. To support this, there's a new `Features` bitflag that can allow up to 63 feature toggles without passing structs. While here, I fixed a significant performance problem in decoding binary: Before ``` BenchmarkCodecExample/binary.DecodeModule-16 184243 5623 ns/op 3848 B/op 184 allocs/op ``` Now ``` BenchmarkCodecExample/binary.DecodeModule-16 294084 3520 ns/op 2176 B/op 91 allocs/op ``` Signed-off-by: Adrian Cole <adrian@tetrate.io>
44 lines
1.1 KiB
Go
44 lines
1.1 KiB
Go
package binary
|
|
|
|
import (
|
|
"bytes"
|
|
"fmt"
|
|
|
|
"github.com/tetratelabs/wazero/internal/leb128"
|
|
wasm "github.com/tetratelabs/wazero/internal/wasm"
|
|
)
|
|
|
|
func decodeExport(r *bytes.Reader) (i *wasm.Export, err error) {
|
|
i = &wasm.Export{}
|
|
|
|
if i.Name, _, err = decodeUTF8(r, "export name"); err != nil {
|
|
return nil, err
|
|
}
|
|
|
|
b, err := r.ReadByte()
|
|
if err != nil {
|
|
return nil, fmt.Errorf("error decoding export kind: %w", err)
|
|
}
|
|
|
|
i.Type = b
|
|
switch i.Type {
|
|
case wasm.ExternTypeFunc, wasm.ExternTypeTable, wasm.ExternTypeMemory, wasm.ExternTypeGlobal:
|
|
if i.Index, _, err = leb128.DecodeUint32(r); err != nil {
|
|
return nil, fmt.Errorf("error decoding export index: %w", err)
|
|
}
|
|
default:
|
|
return nil, fmt.Errorf("%w: invalid byte for exportdesc: %#x", ErrInvalidByte, b)
|
|
}
|
|
return
|
|
}
|
|
|
|
// encodeExport returns the wasm.Export encoded in WebAssembly 1.0 (20191205) Binary Format.
|
|
//
|
|
// See https://www.w3.org/TR/2019/REC-wasm-core-1-20191205/#export-section%E2%91%A0
|
|
func encodeExport(i *wasm.Export) []byte {
|
|
data := encodeSizePrefixed([]byte(i.Name))
|
|
data = append(data, i.Type)
|
|
data = append(data, leb128.EncodeUint32(i.Index)...)
|
|
return data
|
|
}
|