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wasm: use FieldULEB128() / FieldSLEB128() defined in the upstream

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@0xb17bea125 2022-08-22 21:09:26 +09:00
parent 89cb0d8e91
commit d5d9e738b6
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GPG Key ID: 1A292BFDF101D448
2 changed files with 8 additions and 66 deletions
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6
format/wasm/instructions.go
View File

@ -13,7 +13,7 @@ func decodeBlockType(d *decode.D, name string) {
case 0x6f, 0x70, 0x7b, 0x7c, 0x7d, 0x7e, 0x7f:
d.FieldU8(name, valtypeToSymMapper)
default:
d.FieldSScalarFn(name, readSignedLEB128)
d.FieldSLEB128(name)
}
}
@ -460,7 +460,7 @@ func decodePrefixedInstruction(d *decode.D) {
}
func decodePrefixedOpcode(d *decode.D) Opcode {
return Opcode(d.FieldUScalarFn("p_opcode", readUnsignedLEB128, prefixedInstrMap))
return Opcode(d.FieldULEB128("p_opcode", prefixedInstrMap))
}
func decodeMemoryInit(d *decode.D) {
@ -744,7 +744,7 @@ func decodeVectorInstruction(d *decode.D) {
}
func decodeVectorOpcode(d *decode.D) Opcode {
return Opcode(d.FieldUScalarFn("v_opcode", readUnsignedLEB128, vectorInstrMap))
return Opcode(d.FieldULEB128("v_opcode", vectorInstrMap))
}
func decodeV128ConstOperand(d *decode.D) {

68
format/wasm/wasm.go
View File

@ -56,74 +56,16 @@ func decodeVecByte(d *decode.D, name string) {
})
}
// uN ::= n:byte => n (if n < 2^7 && n < 2^N)
// n:byte m:u(N-7) => 2^7 * m + (n - 2^7) (if n >= 2^7 && N > 7)
func readUnsignedLEB128(d *decode.D) scalar.S {
var result uint64
var shift uint
for {
b := d.U8()
if shift >= 63 && b != 0 {
d.Fatalf("overflow when reading unsigned leb128")
}
result |= (b & 0x7f) << shift
if b&0x80 == 0 {
break
}
shift += 7
}
return scalar.S{Actual: result}
}
// sN ::= n:byte => n (if n < 2^6 && n < 2^(N-1))
// n:byte => n - 2^7 (if 2^6 <= n < 2^7 && n >= 2^7 - 2^(N-1))
// n:byte m:s(N-7) => 2^7 * m + (n - 2^7) (if n >= 2^7 && N > 7)
func readSignedLEB128(d *decode.D) scalar.S {
const n = 64
var result int64
var shift uint
var b byte
for {
b = byte(d.U8())
if shift == 63 && b != 0 && b != 0x7f {
d.Fatalf("overflow when reading signed leb128")
}
result |= int64(b&0x7f) << shift
shift += 7
if b&0x80 == 0 {
break
}
}
if shift < n && (b&0x40) == 0x40 {
result |= -1 << shift
}
return scalar.S{Actual: result}
}
func fieldU32(d *decode.D, name string) uint64 {
n := d.FieldUScalarFn(name, readUnsignedLEB128)
if n > math.MaxUint32 {
d.Fatalf("invalid u32 value")
}
return n
return d.FieldULEB128(name, d.AssertURange(0, math.MaxUint32))
}
func fieldI32(d *decode.D, name string) int64 {
n := d.FieldSScalarFn(name, readSignedLEB128)
if n > math.MaxInt32 || n < math.MinInt32 {
d.Fatalf("invalid i32 value")
}
return n
return d.FieldSLEB128(name, d.AssertSRange(math.MinInt32, math.MaxInt32))
}
func fieldI64(d *decode.D, name string) int64 {
return d.FieldSScalarFn(name, readSignedLEB128)
return d.FieldSLEB128(name)
}
// name ::= b*:vec(byte) => name (if utf8(name) = b*)
@ -522,7 +464,7 @@ func decodeDataSegment(d *decode.D, name string) {
// datacountsec ::= n?:section_12(u32) => n?
func decodeDataCountSection(d *decode.D) {
d.FieldUScalarFn("n", readUnsignedLEB128)
fieldU32(d, "n")
}
func decodeWASMModule(d *decode.D) {
@ -532,7 +474,7 @@ func decodeWASMModule(d *decode.D) {
for d.BitsLeft() > 0 {
d.FieldStruct("section", func(d *decode.D) {
sectionID := d.FieldU8("id", sectionIDToSym)
size := d.FieldUScalarFn("size", readUnsignedLEB128)
size := fieldU32(d, "size")
if size > math.MaxInt64/8 {
d.Fatalf("invalid section size")
}