810 lines
16 KiB
Go
810 lines
16 KiB
Go
// Copyright 2018 The OPA Authors. All rights reserved.
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// Use of this source code is governed by an Apache2
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// license that can be found in the LICENSE file.
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package encoding
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import (
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"bytes"
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"encoding/binary"
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"fmt"
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"io"
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"github.com/pkg/errors"
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"github.com/open-policy-agent/opa/internal/leb128"
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"github.com/open-policy-agent/opa/internal/wasm/constant"
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"github.com/open-policy-agent/opa/internal/wasm/instruction"
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"github.com/open-policy-agent/opa/internal/wasm/module"
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"github.com/open-policy-agent/opa/internal/wasm/opcode"
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"github.com/open-policy-agent/opa/internal/wasm/types"
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)
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// ReadModule reads a binary-encoded WASM module from r.
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func ReadModule(r io.Reader) (*module.Module, error) {
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wr := &reader{r: r, n: 0}
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module, err := readModule(wr)
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if err != nil {
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return nil, errors.Wrapf(err, "offset 0x%x", wr.n)
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}
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return module, nil
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}
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// ReadCodeEntry reads a binary-encoded WASM code entry from r.
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func ReadCodeEntry(r io.Reader) (*module.CodeEntry, error) {
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wr := &reader{r: r, n: 0}
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entry, err := readCodeEntry(wr)
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if err != nil {
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return nil, errors.Wrapf(err, "offset 0x%x", wr.n)
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}
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return entry, nil
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}
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// CodeEntries returns the WASM code entries contained in r.
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func CodeEntries(m *module.Module) ([]*module.CodeEntry, error) {
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entries := make([]*module.CodeEntry, len(m.Code.Segments))
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for i, s := range m.Code.Segments {
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buf := bytes.NewBuffer(s.Code)
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entry, err := ReadCodeEntry(buf)
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if err != nil {
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return nil, err
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}
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entries[i] = entry
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}
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return entries, nil
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}
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type reader struct {
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r io.Reader
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n int
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}
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func (r *reader) Read(bs []byte) (int, error) {
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n, err := r.r.Read(bs)
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r.n += n
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return n, err
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}
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func readModule(r io.Reader) (*module.Module, error) {
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if err := readMagic(r); err != nil {
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return nil, err
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}
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if err := readVersion(r); err != nil {
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return nil, err
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}
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var m module.Module
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if err := readSections(r, &m); err != nil && err != io.EOF {
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return nil, err
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}
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return &m, nil
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}
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func readCodeEntry(r io.Reader) (*module.CodeEntry, error) {
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var entry module.CodeEntry
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if err := readLocals(r, &entry.Func.Locals); err != nil {
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return nil, errors.Wrapf(err, "local declarations")
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}
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return &entry, readExpr(r, &entry.Func.Expr)
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}
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func readMagic(r io.Reader) error {
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var v uint32
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if err := binary.Read(r, binary.LittleEndian, &v); err != nil {
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return err
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} else if v != constant.Magic {
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return fmt.Errorf("illegal magic value")
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}
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return nil
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}
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func readVersion(r io.Reader) error {
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var v uint32
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if err := binary.Read(r, binary.LittleEndian, &v); err != nil {
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return err
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} else if v != constant.Version {
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return fmt.Errorf("illegal wasm version")
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}
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return nil
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}
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func readSections(r io.Reader, m *module.Module) error {
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for {
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id, err := readByte(r)
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if err != nil {
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return err
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}
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size, err := leb128.ReadVarUint32(r)
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if err != nil {
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return err
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}
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buf := make([]byte, size)
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if _, err := io.ReadFull(r, buf); err != nil {
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return err
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}
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bufr := bytes.NewReader(buf)
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switch id {
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case constant.CustomSectionID, constant.StartSectionID, constant.MemorySectionID:
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continue
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case constant.TypeSectionID:
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if err := readTypeSection(bufr, &m.Type); err != nil {
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return errors.Wrap(err, "type section")
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}
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case constant.ImportSectionID:
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if err := readImportSection(bufr, &m.Import); err != nil {
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return errors.Wrap(err, "import section")
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}
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case constant.GlobalSectionID:
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if err := readGlobalSection(bufr, &m.Global); err != nil {
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return errors.Wrap(err, "global section")
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}
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case constant.TableSectionID:
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if err := readTableSection(bufr, &m.Table); err != nil {
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return errors.Wrap(err, "table section")
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}
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case constant.FunctionSectionID:
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if err := readFunctionSection(bufr, &m.Function); err != nil {
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return errors.Wrap(err, "function section")
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}
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case constant.ExportSectionID:
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if err := readExportSection(bufr, &m.Export); err != nil {
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return errors.Wrap(err, "export section")
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}
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case constant.ElementSectionID:
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if err := readElementSection(bufr, &m.Element); err != nil {
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return errors.Wrap(err, "element section")
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}
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case constant.DataSectionID:
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if err := readDataSection(bufr, &m.Data); err != nil {
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return errors.Wrap(err, "data section")
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}
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case constant.CodeSectionID:
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if err := readRawCodeSection(bufr, &m.Code); err != nil {
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return errors.Wrap(err, "code section")
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}
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default:
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return fmt.Errorf("illegal section id")
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}
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}
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}
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func readTypeSection(r io.Reader, s *module.TypeSection) error {
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n, err := leb128.ReadVarUint32(r)
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if err != nil {
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return err
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}
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for i := uint32(0); i < n; i++ {
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var ftype module.FunctionType
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if err := readFunctionType(r, &ftype); err != nil {
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return err
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}
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s.Functions = append(s.Functions, ftype)
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}
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return nil
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}
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func readImportSection(r io.Reader, s *module.ImportSection) error {
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n, err := leb128.ReadVarUint32(r)
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if err != nil {
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return err
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}
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for i := uint32(0); i < n; i++ {
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var imp module.Import
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if err := readImport(r, &imp); err != nil {
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return err
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}
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s.Imports = append(s.Imports, imp)
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}
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return nil
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}
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func readTableSection(r io.Reader, s *module.TableSection) error {
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n, err := leb128.ReadVarUint32(r)
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if err != nil {
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return err
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}
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for i := uint32(0); i < n; i++ {
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var table module.Table
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if elem, err := readByte(r); err != nil {
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return err
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} else if elem != constant.ElementTypeAnyFunc {
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return fmt.Errorf("illegal element type")
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} else {
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table.Type = types.Anyfunc
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}
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if err := readLimits(r, &table.Lim); err != nil {
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return err
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}
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s.Tables = append(s.Tables, table)
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}
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return nil
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}
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func readGlobalSection(r io.Reader, s *module.GlobalSection) error {
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n, err := leb128.ReadVarUint32(r)
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if err != nil {
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return err
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}
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for i := uint32(0); i < n; i++ {
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var global module.Global
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if err := readGlobal(r, &global); err != nil {
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return err
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}
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s.Globals = append(s.Globals, global)
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}
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return nil
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}
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func readFunctionSection(r io.Reader, s *module.FunctionSection) error {
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return readVarUint32Vector(r, &s.TypeIndices)
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}
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func readExportSection(r io.Reader, s *module.ExportSection) error {
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n, err := leb128.ReadVarUint32(r)
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if err != nil {
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return err
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}
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for i := uint32(0); i < n; i++ {
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var exp module.Export
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if err := readExport(r, &exp); err != nil {
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return err
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}
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s.Exports = append(s.Exports, exp)
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}
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return nil
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}
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func readElementSection(r io.Reader, s *module.ElementSection) error {
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n, err := leb128.ReadVarUint32(r)
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if err != nil {
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return err
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}
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for i := uint32(0); i < n; i++ {
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var seg module.ElementSegment
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if err := readElementSegment(r, &seg); err != nil {
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return err
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}
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s.Segments = append(s.Segments, seg)
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}
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return nil
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}
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func readDataSection(r io.Reader, s *module.DataSection) error {
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n, err := leb128.ReadVarUint32(r)
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if err != nil {
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return err
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}
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for i := uint32(0); i < n; i++ {
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var seg module.DataSegment
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if err := readDataSegment(r, &seg); err != nil {
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return err
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}
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s.Segments = append(s.Segments, seg)
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}
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return nil
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}
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func readRawCodeSection(r io.Reader, s *module.RawCodeSection) error {
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n, err := leb128.ReadVarUint32(r)
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if err != nil {
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return err
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}
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for i := uint32(0); i < n; i++ {
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var seg module.RawCodeSegment
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if err := readRawCodeSegment(r, &seg); err != nil {
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return err
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}
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s.Segments = append(s.Segments, seg)
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}
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return nil
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}
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func readFunctionType(r io.Reader, ftype *module.FunctionType) error {
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if b, err := readByte(r); err != nil {
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return err
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} else if b != constant.FunctionTypeID {
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return fmt.Errorf("illegal function type id 0x%x", b)
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}
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if err := readValueTypeVector(r, &ftype.Params); err != nil {
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return err
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}
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return readValueTypeVector(r, &ftype.Results)
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}
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func readGlobal(r io.Reader, global *module.Global) error {
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if err := readValueType(r, &global.Type); err != nil {
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return err
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}
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b, err := readByte(r)
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if err != nil {
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return err
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}
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if b == 1 {
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global.Mutable = true
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} else if b != 0 {
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return fmt.Errorf("illegal mutability flag")
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}
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if err := readConstantExpr(r, &global.Init); err != nil {
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return err
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}
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return nil
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}
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func readImport(r io.Reader, imp *module.Import) error {
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if err := readByteVectorString(r, &imp.Module); err != nil {
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return err
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}
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if err := readByteVectorString(r, &imp.Name); err != nil {
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return err
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}
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b, err := readByte(r)
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if err != nil {
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return err
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}
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if b == constant.ImportDescType {
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index, err := leb128.ReadVarUint32(r)
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if err != nil {
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return err
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}
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imp.Descriptor = module.FunctionImport{
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Func: index,
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}
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return nil
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}
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if b == constant.ImportDescTable {
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if elem, err := readByte(r); err != nil {
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return err
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} else if elem != constant.ElementTypeAnyFunc {
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return fmt.Errorf("illegal element type")
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}
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desc := module.TableImport{
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Type: types.Anyfunc,
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}
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if err := readLimits(r, &desc.Lim); err != nil {
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return err
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}
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imp.Descriptor = desc
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return nil
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}
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if b == constant.ImportDescMem {
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desc := module.MemoryImport{}
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if err := readLimits(r, &desc.Mem.Lim); err != nil {
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return err
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}
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imp.Descriptor = desc
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return nil
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}
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if b == constant.ImportDescGlobal {
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desc := module.GlobalImport{}
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if err := readValueType(r, &desc.Type); err != nil {
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return err
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}
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b, err := readByte(r)
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if err != nil {
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return err
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}
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if b == 1 {
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desc.Mutable = true
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} else if b != 0 {
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return fmt.Errorf("illegal mutability flag")
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}
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return nil
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}
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return fmt.Errorf("illegal import descriptor type")
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}
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func readExport(r io.Reader, exp *module.Export) error {
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if err := readByteVectorString(r, &exp.Name); err != nil {
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return err
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}
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b, err := readByte(r)
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if err != nil {
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return err
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}
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switch b {
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case constant.ExportDescType:
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exp.Descriptor.Type = module.FunctionExportType
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case constant.ExportDescTable:
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exp.Descriptor.Type = module.TableExportType
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case constant.ExportDescMem:
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exp.Descriptor.Type = module.MemoryExportType
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case constant.ExportDescGlobal:
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exp.Descriptor.Type = module.GlobalExportType
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default:
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return fmt.Errorf("illegal export descriptor type")
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}
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exp.Descriptor.Index, err = leb128.ReadVarUint32(r)
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if err != nil {
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return err
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}
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return nil
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}
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func readElementSegment(r io.Reader, seg *module.ElementSegment) error {
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if err := readVarUint32(r, &seg.Index); err != nil {
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return err
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}
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if err := readConstantExpr(r, &seg.Offset); err != nil {
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return err
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}
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if err := readVarUint32Vector(r, &seg.Indices); err != nil {
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return err
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}
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return nil
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}
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func readDataSegment(r io.Reader, seg *module.DataSegment) error {
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if err := readVarUint32(r, &seg.Index); err != nil {
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return err
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}
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if err := readConstantExpr(r, &seg.Offset); err != nil {
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return err
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}
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if err := readByteVector(r, &seg.Init); err != nil {
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return err
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}
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return nil
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}
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func readRawCodeSegment(r io.Reader, seg *module.RawCodeSegment) error {
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return readByteVector(r, &seg.Code)
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}
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func readConstantExpr(r io.Reader, expr *module.Expr) error {
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instrs := make([]instruction.Instruction, 0)
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for {
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b, err := readByte(r)
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if err != nil {
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return err
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}
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switch opcode.Opcode(b) {
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case opcode.I32Const:
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i32, err := leb128.ReadVarInt32(r)
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if err != nil {
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return err
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}
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instrs = append(instrs, instruction.I32Const{Value: i32})
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case opcode.I64Const:
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i64, err := leb128.ReadVarInt64(r)
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if err != nil {
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return err
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}
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instrs = append(instrs, instruction.I64Const{Value: i64})
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case opcode.End:
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expr.Instrs = instrs
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return nil
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default:
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return fmt.Errorf("illegal constant expr opcode 0x%x", b)
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}
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}
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}
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func readExpr(r io.Reader, expr *module.Expr) (err error) {
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defer func() {
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if r := recover(); r != nil {
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switch r := r.(type) {
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case error:
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err = r
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default:
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err = fmt.Errorf("unknown panic")
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}
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}
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}()
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return readInstructions(r, &expr.Instrs)
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}
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func readInstructions(r io.Reader, instrs *[]instruction.Instruction) error {
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ret := make([]instruction.Instruction, 0)
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for {
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b, err := readByte(r)
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if err != nil {
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return err
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}
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switch opcode.Opcode(b) {
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case opcode.I32Const:
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ret = append(ret, instruction.I32Const{Value: leb128.MustReadVarInt32(r)})
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case opcode.I64Const:
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ret = append(ret, instruction.I64Const{Value: leb128.MustReadVarInt64(r)})
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case opcode.I32Eqz:
|
|
ret = append(ret, instruction.I32Eqz{})
|
|
case opcode.GetLocal:
|
|
ret = append(ret, instruction.GetLocal{Index: leb128.MustReadVarUint32(r)})
|
|
case opcode.SetLocal:
|
|
ret = append(ret, instruction.SetLocal{Index: leb128.MustReadVarUint32(r)})
|
|
case opcode.Call:
|
|
ret = append(ret, instruction.Call{Index: leb128.MustReadVarUint32(r)})
|
|
case opcode.BrIf:
|
|
ret = append(ret, instruction.BrIf{Index: leb128.MustReadVarUint32(r)})
|
|
case opcode.Return:
|
|
ret = append(ret, instruction.Return{})
|
|
case opcode.Block:
|
|
block := instruction.Block{}
|
|
if err := readBlockValueType(r, block.Type); err != nil {
|
|
return err
|
|
}
|
|
if err := readInstructions(r, &block.Instrs); err != nil {
|
|
return err
|
|
}
|
|
ret = append(ret, block)
|
|
case opcode.Loop:
|
|
loop := instruction.Loop{}
|
|
if err := readBlockValueType(r, loop.Type); err != nil {
|
|
return err
|
|
}
|
|
if err := readInstructions(r, &loop.Instrs); err != nil {
|
|
return err
|
|
}
|
|
ret = append(ret, loop)
|
|
case opcode.End:
|
|
*instrs = ret
|
|
return nil
|
|
default:
|
|
return fmt.Errorf("illegal opcode 0x%x", b)
|
|
}
|
|
}
|
|
}
|
|
|
|
func readLimits(r io.Reader, l *module.Limit) error {
|
|
|
|
b, err := readByte(r)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
|
|
min, err := leb128.ReadVarUint32(r)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
|
|
l.Min = min
|
|
|
|
if b == 1 {
|
|
max, err := leb128.ReadVarUint32(r)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
l.Max = &max
|
|
} else if b != 0 {
|
|
return fmt.Errorf("illegal limit flag")
|
|
}
|
|
|
|
return nil
|
|
}
|
|
|
|
func readLocals(r io.Reader, locals *[]module.LocalDeclaration) error {
|
|
|
|
n, err := leb128.ReadVarUint32(r)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
|
|
ret := make([]module.LocalDeclaration, n)
|
|
|
|
for i := uint32(0); i < n; i++ {
|
|
if err := readVarUint32(r, &ret[i].Count); err != nil {
|
|
return err
|
|
}
|
|
if err := readValueType(r, &ret[i].Type); err != nil {
|
|
return err
|
|
}
|
|
}
|
|
|
|
*locals = ret
|
|
return nil
|
|
}
|
|
|
|
func readByteVector(r io.Reader, v *[]byte) error {
|
|
|
|
n, err := leb128.ReadVarUint32(r)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
|
|
buf := make([]byte, n)
|
|
if _, err := io.ReadFull(r, buf); err != nil {
|
|
return err
|
|
}
|
|
|
|
*v = buf
|
|
return nil
|
|
}
|
|
|
|
func readByteVectorString(r io.Reader, v *string) error {
|
|
|
|
var buf []byte
|
|
|
|
if err := readByteVector(r, &buf); err != nil {
|
|
return err
|
|
}
|
|
|
|
*v = string(buf)
|
|
return nil
|
|
}
|
|
|
|
func readVarUint32Vector(r io.Reader, v *[]uint32) error {
|
|
|
|
n, err := leb128.ReadVarUint32(r)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
|
|
ret := make([]uint32, n)
|
|
|
|
for i := uint32(0); i < n; i++ {
|
|
if err := readVarUint32(r, &ret[i]); err != nil {
|
|
return err
|
|
}
|
|
}
|
|
|
|
*v = ret
|
|
return nil
|
|
}
|
|
|
|
func readValueTypeVector(r io.Reader, v *[]types.ValueType) error {
|
|
|
|
n, err := leb128.ReadVarUint32(r)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
|
|
ret := make([]types.ValueType, n)
|
|
|
|
for i := uint32(0); i < n; i++ {
|
|
if err := readValueType(r, &ret[i]); err != nil {
|
|
return err
|
|
}
|
|
}
|
|
|
|
*v = ret
|
|
return nil
|
|
}
|
|
|
|
func readVarUint32(r io.Reader, v *uint32) error {
|
|
var err error
|
|
*v, err = leb128.ReadVarUint32(r)
|
|
return err
|
|
}
|
|
|
|
func readValueType(r io.Reader, v *types.ValueType) error {
|
|
if b, err := readByte(r); err != nil {
|
|
return err
|
|
} else if b == constant.ValueTypeI32 {
|
|
*v = types.I32
|
|
} else if b == constant.ValueTypeI64 {
|
|
*v = types.I64
|
|
} else if b == constant.ValueTypeF32 {
|
|
*v = types.F32
|
|
} else if b == constant.ValueTypeF64 {
|
|
*v = types.F64
|
|
} else {
|
|
return fmt.Errorf("illegal value type: 0x%x", b)
|
|
}
|
|
return nil
|
|
}
|
|
|
|
func readBlockValueType(r io.Reader, v *types.ValueType) error {
|
|
if b, err := readByte(r); err != nil {
|
|
return err
|
|
} else if b == constant.ValueTypeI32 {
|
|
*v = types.I32
|
|
} else if b == constant.ValueTypeI64 {
|
|
*v = types.I64
|
|
} else if b == constant.ValueTypeF32 {
|
|
*v = types.F32
|
|
} else if b == constant.ValueTypeF64 {
|
|
*v = types.F64
|
|
} else if b != constant.BlockTypeEmpty {
|
|
return fmt.Errorf("illegal value type: 0x%x", b)
|
|
}
|
|
return nil
|
|
}
|
|
|
|
func readByte(r io.Reader) (byte, error) {
|
|
buf := make([]byte, 1)
|
|
_, err := r.Read(buf)
|
|
return buf[0], err
|
|
}
|