mirror of
https://github.com/wader/fq.git
synced 2024-09-19 15:57:29 +03:00
611 lines
15 KiB
Go
611 lines
15 KiB
Go
package wasm
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// https://webassembly.github.io/spec/core/
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import (
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"embed"
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"math"
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"sync"
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"github.com/wader/fq/format"
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"github.com/wader/fq/pkg/decode"
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"github.com/wader/fq/pkg/interp"
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"github.com/wader/fq/pkg/scalar"
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)
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//go:embed wasm.md
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var wasmFS embed.FS
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func init() {
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interp.RegisterFormat(
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format.WASM,
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&decode.Format{
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Description: "WebAssembly Binary Format",
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DecodeFn: decodeWASM,
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Groups: []*decode.Group{format.Probe},
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})
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interp.RegisterFS(wasmFS)
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}
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const (
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sectionIDCustom = 0x00
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sectionIDType = 0x01
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sectionIDImport = 0x02
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sectionIDFunction = 0x03
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sectionIDTable = 0x04
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sectionIDMemory = 0x05
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sectionIDGlobal = 0x06
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sectionIDExport = 0x07
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sectionIDStart = 0x08
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sectionIDElement = 0x09
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sectionIDCode = 0x0a
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sectionIDData = 0x0b
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sectionIDDataCount = 0x0c
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)
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// Decode vector.
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//
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// vec(B) ::= n:u32 (x:B)^n => x^n
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func decodeVec(d *decode.D, name string, fn func(d *decode.D)) {
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d.FieldStruct(name, func(d *decode.D) {
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n := fieldU32(d, "n")
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d.FieldArray("x", func(d *decode.D) {
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for i := uint64(0); i < n; i++ {
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fn(d)
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}
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})
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})
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}
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func decodeVecByte(d *decode.D, name string) {
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d.FieldStruct(name, func(d *decode.D) {
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n := fieldU32(d, "n")
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d.FieldRawLen("x", int64(n)*8)
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})
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}
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func fieldU32(d *decode.D, name string) uint64 {
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return d.FieldULEB128(name, d.UintAssertRange(0, math.MaxUint32))
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}
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func fieldI32(d *decode.D, name string) int64 {
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return d.FieldSLEB128(name, d.SintAssertRange(math.MinInt32, math.MaxInt32))
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}
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func fieldI64(d *decode.D, name string) int64 {
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return d.FieldSLEB128(name)
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}
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// Decode name.
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//
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// name ::= b*:vec(byte) => name (if utf8(name) = b*)
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func decodeName(d *decode.D, name string) {
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d.FieldStruct(name, func(d *decode.D) {
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n := fieldU32(d, "n")
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if n > math.MaxInt {
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d.Fatalf("invalid length of custom section name")
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}
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d.FieldUTF8("b", int(n))
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})
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}
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// Decode reftype.
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//
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// reftype ::= 0x70 => funcref
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// | 0x6F => externref
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func decodeRefType(d *decode.D, name string) {
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d.FieldU8(name, reftypeTagToSym)
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}
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// Decode valtype.
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//
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// valtype ::= t:numtype => t
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// | t:vectype => t
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// | t:reftype => t
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//
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//nolint:unparam
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func decodeValType(d *decode.D, name string) {
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d.FieldU8(name, valtypeToSymMapper, scalar.UintHex)
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}
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// Decode resulttype.
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//
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// resulttype ::= t*:vec(valtype) => [t*]
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func decodeResultType(d *decode.D, name string) {
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decodeVec(d, name, func(d *decode.D) {
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decodeValType(d, "t")
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})
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}
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// Decode functype.
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//
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// functype ::= 0x60 rt1:resulttype rt2:resulttype => rt1 -> rt2
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func decodeFuncType(d *decode.D, name string) {
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d.FieldStruct(name, func(d *decode.D) {
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d.FieldU8("tag", d.UintAssert(0x60), scalar.UintHex)
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decodeResultType(d, "rt1")
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decodeResultType(d, "rt2")
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})
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}
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// Decode limits.
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//
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// limits ::= 0x00 n:u32 => {min: n, max: ε}
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// | 0x01 n:u32 m:u32 => {min: n, max: m}
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func decodeLimits(d *decode.D, name string) {
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d.FieldStruct(name, func(d *decode.D) {
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tag := d.FieldU8("tag", scalar.UintHex)
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switch tag {
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case 0x00:
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fieldU32(d, "n")
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case 0x01:
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fieldU32(d, "n")
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fieldU32(d, "m")
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default:
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d.Fatalf("unknown limits type")
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}
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})
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}
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// Decode memtype.
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//
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// memtype ::= lim:limits => lim
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func decodeMemType(d *decode.D, name string) {
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d.FieldStruct(name, func(d *decode.D) {
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decodeLimits(d, "lim")
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})
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}
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// Decode tabletype.
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//
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// tabletype ::= et:reftype lim:limits => lim et
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func decodeTableType(d *decode.D, name string) {
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d.FieldStruct(name, func(d *decode.D) {
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decodeRefType(d, "et")
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decodeLimits(d, "lim")
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})
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}
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// Decode globaltype.
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//
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// globaltype ::= t:valtype m:mut => m t
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// mut ::= 0x00 => const
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// | 0x01 => var
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func decodeGlobalType(d *decode.D, name string) {
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d.FieldStruct(name, func(d *decode.D) {
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decodeValType(d, "t")
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d.FieldU8("m", mutToSym)
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})
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}
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// Decode typeidx.
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//
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// typeidx ::= x:u32 => x
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func decodeTypeIdx(d *decode.D, name string) {
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fieldU32(d, name)
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}
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// Decode funcidx.
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//
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// funcidx ::= x:u32 => x
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func decodeFuncIdx(d *decode.D, name string) {
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fieldU32(d, name)
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}
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// Decode tableidx.
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//
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// tableidx ::= x:u32 => x
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func decodeTableIdx(d *decode.D, name string) {
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fieldU32(d, name)
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}
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// Decode memidx.
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//
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// memidx ::= x:u32 => x
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func decodeMemIdx(d *decode.D, name string) {
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fieldU32(d, name)
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}
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// Decode globalidx.
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//
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// globalidx ::= x:u32 => x
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func decodeGlobalIdx(d *decode.D, name string) {
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fieldU32(d, name)
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}
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// Decode elemidx.
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//
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// elemidx ::= x:u32 => x
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func decodeElemIdx(d *decode.D, name string) {
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fieldU32(d, name)
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}
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// Decode dataidx.
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//
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// dataidx ::= x:u32 => x
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func decodeDataIdx(d *decode.D, name string) {
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fieldU32(d, name)
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}
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// Decode localidx.
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//
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// localidx ::= x:u32 => x
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func decodeLocalIdx(d *decode.D, name string) {
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fieldU32(d, name)
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}
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// Decode labelidx.
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//
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// labelidx ::= l:u32 => l
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func decodeLabelIdx(d *decode.D, name string) {
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fieldU32(d, name)
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}
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// Decode custom section.
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//
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// customsec ::= section_0(custom)
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// custom ::= name byte*
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func decodeCustomSection(d *decode.D) {
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decodeName(d, "name")
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d.FieldRawLen("bytes", d.BitsLeft())
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}
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// Decode type section.
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//
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// typesec ::= ft*:section_1(vec(functype)) => ft*
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func decodeTypeSection(d *decode.D) {
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decodeVec(d, "ft", func(d *decode.D) {
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decodeFuncType(d, "ft")
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})
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}
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// Decode import section.
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//
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// importsec ::= im*:section_2(vec(import)) => im*
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// import ::= mod:name nm:name d:importdesc => {module mod, name nm, desc d}
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// importdesc ::= 0x00 x:typeidx => func x
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// | 0x01 tt:tabletype => table tt
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// | 0x02 mt:memtype => mem mt
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// | 0x03 gt:globaltype => global gt
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func decodeImportSection(d *decode.D) {
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decodeVec(d, "im", func(d *decode.D) {
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decodeImportSegment(d, "im")
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})
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}
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func decodeImportSegment(d *decode.D, name string) {
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d.FieldStruct(name, func(d *decode.D) {
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decodeName(d, "mod")
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decodeName(d, "nm")
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decodeImportDesc(d, "d")
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})
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}
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func decodeImportDesc(d *decode.D, name string) {
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d.FieldStruct(name, func(d *decode.D) {
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tag := d.FieldU8("tag", importdescTagToSym, scalar.UintHex)
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switch tag {
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case 0x00:
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decodeTypeIdx(d, "x")
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case 0x01:
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decodeTableType(d, "tt")
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case 0x02:
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decodeMemType(d, "mt")
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case 0x03:
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decodeGlobalType(d, "gt")
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default:
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d.Fatalf("unknown import desc")
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}
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})
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}
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// Decode function section.
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//
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// funcsec ::= x*:section_3(vec(typeidx)) => x*
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func decodeFunctionSection(d *decode.D) {
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decodeVec(d, "x", func(d *decode.D) {
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decodeTypeIdx(d, "x")
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})
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}
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// Decode table section.
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//
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// tablesec ::= tab*:section_4(vec(table)) => tab*
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// table ::= tt:tabletype => {type tt}
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func decodeTableSection(d *decode.D) {
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decodeVec(d, "tab", func(d *decode.D) {
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decodeTableType(d, "tab")
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})
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}
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// Decode memory section.
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//
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// memsec ::= mem*:section_5(vec(mem)) => mem*
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// mem ::= mt:memtype => {type mt}
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func decodeMemorySection(d *decode.D) {
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decodeVec(d, "mem", func(d *decode.D) {
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decodeMemType(d, "mem")
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})
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}
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// Decode global section.
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//
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// globalsec ::= glob*:section_6(vec(global)) => glob*
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// global ::= gt:globaltype e:expr => {type gt, init e}
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func decodeGlobalSection(d *decode.D) {
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decodeVec(d, "glob", func(d *decode.D) {
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decodeGlobal(d, "glob")
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})
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}
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func decodeGlobal(d *decode.D, name string) {
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d.FieldStruct(name, func(d *decode.D) {
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decodeGlobalType(d, "gt")
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decodeExpr(d, "e")
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})
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}
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// Decode export section.
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//
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// exportsec ::= ex*:section_7(vec(export)) => ex*
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// export ::= nm:name d:exportdesc => {name nm, desc d}
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// exportdesc ::= 0x00 x:funcidx => func x
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// | 0x01 x:tableidx => table x
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// | 0x02 x:memidx => mem x
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// | 0x03 x:globalidx => global x
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func decodeExportSection(d *decode.D) {
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decodeVec(d, "ex", func(d *decode.D) {
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decodeExport(d, "ex")
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})
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}
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func decodeExport(d *decode.D, name string) {
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d.FieldStruct(name, func(d *decode.D) {
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decodeName(d, "nm")
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decodeExportDesc(d, "d")
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})
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}
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func decodeExportDesc(d *decode.D, name string) {
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d.FieldStruct(name, func(d *decode.D) {
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tag := d.FieldU8("tag", exportdescTagToSym, scalar.UintHex)
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switch tag {
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case 0x00:
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decodeFuncIdx(d, "x")
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case 0x01:
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decodeTableIdx(d, "x")
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case 0x02:
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decodeMemIdx(d, "x")
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case 0x03:
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decodeGlobalIdx(d, "x")
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default:
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d.Fatalf("unknown export desc")
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}
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})
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}
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// Decode start section.
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//
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// startsec ::= st?:section_8(start) => st?
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// start ::= x:funcidx => {func x}
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func decodeStartSection(d *decode.D) {
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decodeStart(d, "st")
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}
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func decodeStart(d *decode.D, name string) {
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d.FieldStruct(name, func(d *decode.D) {
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decodeFuncIdx(d, "x")
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})
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}
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// Decode element section.
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//
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// elemsec ::= seg*:section_9(vec(elem)) => seg*
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// elem ::= 0:u32 e:expr y*:vec(funcidx) => {type funcref, init ((ref.func y) end)*, mode active {table 0, offset e}}
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// | 1:u32 et:elemkind y*:vec(funcidx) => {type et, init ((ref.func y) end)*, mode passive}
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// | 2:u32 x:tableidx e:expr et:elemkind y*:vec(funcidx) => {type et, init ((ref.func y) end)*, mode active {table x, offset e}}
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// | 3:u32 et:elemkind y*:vec(funcidx) => {type et, init ((ref.func y) end)*, mode declarative}
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// | 4:u32 e:expr el*:vec(expr) => {type funcref, init el*, mode active {table 0, offset e}}
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// | 5:u32 et:reftype el*:vec(expr) => {type et, init el*, mode passive}
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// | 6:u32 x:tableidx e:expr et:reftype el*:vec(expr) => {type et, init el*, mode active {table x, offset e}}
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// | 7:u32 et:reftype el*:vec(expr) => {type et, init el*, mode declarative}
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func decodeElementSection(d *decode.D) {
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decodeVec(d, "seg", func(d *decode.D) {
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decodeElem(d, "seg")
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})
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}
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func decodeElem(d *decode.D, name string) {
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d.FieldStruct(name, func(d *decode.D) {
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tag := fieldU32(d, "tag")
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switch tag {
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case 0:
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decodeExpr(d, "e")
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decodeVec(d, "y", func(d *decode.D) {
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decodeFuncIdx(d, "y")
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})
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case 1, 3:
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decodeElemKind(d, "et")
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decodeVec(d, "y", func(d *decode.D) {
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decodeFuncIdx(d, "y")
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})
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case 2:
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decodeTableIdx(d, "x")
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decodeExpr(d, "e")
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decodeElemKind(d, "et")
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decodeVec(d, "y", func(d *decode.D) {
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decodeFuncIdx(d, "y")
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})
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case 4:
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decodeExpr(d, "e")
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decodeVec(d, "el", func(d *decode.D) {
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decodeExpr(d, "el")
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})
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case 5, 7:
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decodeRefType(d, "et")
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decodeVec(d, "el", func(d *decode.D) {
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decodeExpr(d, "el")
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})
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case 6:
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decodeTableIdx(d, "x")
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decodeExpr(d, "e")
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decodeRefType(d, "et")
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decodeVec(d, "el", func(d *decode.D) {
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decodeExpr(d, "el")
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})
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default:
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d.Fatalf("unknown elem type")
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}
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})
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}
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func decodeElemKind(d *decode.D, name string) {
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d.FieldU8(name, d.UintAssert(0x00), elemkindTagToSym)
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}
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// Decode code section.
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//
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// codesec ::= code*:section_10(vec(code)) => code*
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// code ::= size:u32 code:func => code (if size = ||func||)
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// func ::= (t*)*:vec(locals) e:expr => concat((t*)*),e (if |concat((t*)*)| < 2^32)
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// locals ::= n:u32 t:valtype => t^n
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func decodeCodeSection(d *decode.D) {
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decodeVec(d, "code", func(d *decode.D) {
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decodeCode(d, "code")
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})
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}
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func decodeCode(d *decode.D, name string) {
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d.FieldStruct(name, func(d *decode.D) {
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size := fieldU32(d, "size")
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d.FramedFn(int64(size)*8, func(d *decode.D) {
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decodeFunc(d, "code")
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})
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})
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}
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func decodeFunc(d *decode.D, name string) {
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d.FieldStruct(name, func(d *decode.D) {
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decodeVec(d, "t", func(d *decode.D) {
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decodeLocals(d, "t")
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})
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decodeExpr(d, "e")
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})
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}
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func decodeLocals(d *decode.D, name string) {
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d.FieldStruct(name, func(d *decode.D) {
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fieldU32(d, "n")
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decodeValType(d, "t")
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})
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}
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// Decode data section.
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//
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// datasec ::= seg*:section_11(vec(data)) => seg*
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// data ::= 0:u32 e:expr b*:vec(byte) => {init b*, mode active {memory 0, offset e}}
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// | 1:u32 b*:vec(byte) => {init b*, mode passive}
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// | 2:u32 x:memidx e:expr b*:vec(byte) => {init b*, mode active {memory x, offset e}}
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func decodeDataSection(d *decode.D) {
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decodeVec(d, "seg", func(d *decode.D) {
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decodeDataSegment(d, "seg")
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})
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|
}
|
|
|
|
func decodeDataSegment(d *decode.D, name string) {
|
|
d.FieldStruct(name, func(d *decode.D) {
|
|
tag := fieldU32(d, "tag")
|
|
switch tag {
|
|
case 0:
|
|
decodeExpr(d, "e")
|
|
decodeVecByte(d, "b")
|
|
case 1:
|
|
decodeVecByte(d, "b")
|
|
case 2:
|
|
decodeMemIdx(d, "x")
|
|
decodeExpr(d, "e")
|
|
decodeVecByte(d, "b")
|
|
default:
|
|
d.Fatalf("unknown data segment type")
|
|
}
|
|
})
|
|
}
|
|
|
|
// Decode data count section.
|
|
//
|
|
// datacountsec ::= n?:section_12(u32) => n?
|
|
func decodeDataCountSection(d *decode.D) {
|
|
fieldU32(d, "n")
|
|
}
|
|
|
|
func decodeWASMModule(d *decode.D) {
|
|
d.FieldRawLen("magic", 4*8, d.AssertBitBuf([]byte("\x00asm")))
|
|
d.FieldU32("version")
|
|
d.FieldArray("sections", func(d *decode.D) {
|
|
for d.BitsLeft() > 0 {
|
|
d.FieldStruct("section", func(d *decode.D) {
|
|
sectionID := d.FieldU8("id", sectionIDToSym)
|
|
size := fieldU32(d, "size")
|
|
if size > math.MaxInt64/8 {
|
|
d.Fatalf("invalid section size")
|
|
}
|
|
d.FramedFn(int64(size)*8, func(d *decode.D) {
|
|
switch sectionID {
|
|
case sectionIDCustom:
|
|
d.FieldStruct("content", decodeCustomSection)
|
|
case sectionIDType:
|
|
d.FieldStruct("content", decodeTypeSection)
|
|
case sectionIDImport:
|
|
d.FieldStruct("content", decodeImportSection)
|
|
case sectionIDFunction:
|
|
d.FieldStruct("content", decodeFunctionSection)
|
|
case sectionIDTable:
|
|
d.FieldStruct("content", decodeTableSection)
|
|
case sectionIDMemory:
|
|
d.FieldStruct("content", decodeMemorySection)
|
|
case sectionIDGlobal:
|
|
d.FieldStruct("content", decodeGlobalSection)
|
|
case sectionIDExport:
|
|
d.FieldStruct("content", decodeExportSection)
|
|
case sectionIDStart:
|
|
d.FieldStruct("content", decodeStartSection)
|
|
case sectionIDElement:
|
|
d.FieldStruct("element", decodeElementSection)
|
|
case sectionIDCode:
|
|
d.FieldStruct("content", decodeCodeSection)
|
|
case sectionIDData:
|
|
d.FieldStruct("content", decodeDataSection)
|
|
case sectionIDDataCount:
|
|
d.FieldStruct("content", decodeDataCountSection)
|
|
default:
|
|
d.FieldRawLen("value", d.BitsLeft())
|
|
}
|
|
})
|
|
})
|
|
}
|
|
})
|
|
}
|
|
|
|
var instrMapOnce sync.Once
|
|
|
|
const (
|
|
opcodeBlock Opcode = 0x02
|
|
opcodeLoop Opcode = 0x03
|
|
opcodeIf Opcode = 0x04
|
|
)
|
|
|
|
func decodeWASM(d *decode.D) any {
|
|
d.Endian = decode.LittleEndian
|
|
|
|
// delayed initialization to break initialization reference cycle
|
|
instrMapOnce.Do(func() {
|
|
instrMap[opcodeBlock] = instructionInfo{mnemonic: "block", f: decodeBlock}
|
|
instrMap[opcodeLoop] = instructionInfo{mnemonic: "loop", f: decodeLoop}
|
|
instrMap[opcodeIf] = instructionInfo{mnemonic: "if", f: decodeIf}
|
|
})
|
|
|
|
decodeWASMModule(d)
|
|
|
|
return nil
|
|
}
|