Source file src/go/internal/gccgoimporter/parser.go

     1  // Copyright 2013 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  package gccgoimporter
     6  
     7  import (
     8  	"errors"
     9  	"fmt"
    10  	"go/constant"
    11  	"go/token"
    12  	"go/types"
    13  	"io"
    14  	"strconv"
    15  	"strings"
    16  	"text/scanner"
    17  	"unicode/utf8"
    18  )
    19  
    20  type parser struct {
    21  	scanner  *scanner.Scanner
    22  	version  string                    // format version
    23  	tok      rune                      // current token
    24  	lit      string                    // literal string; only valid for Ident, Int, String tokens
    25  	pkgpath  string                    // package path of imported package
    26  	pkgname  string                    // name of imported package
    27  	pkg      *types.Package            // reference to imported package
    28  	imports  map[string]*types.Package // package path -> package object
    29  	typeList []types.Type              // type number -> type
    30  	typeData []string                  // unparsed type data (v3 and later)
    31  	fixups   []fixupRecord             // fixups to apply at end of parsing
    32  	initdata InitData                  // package init priority data
    33  	aliases  map[int]string            // maps saved type number to alias name
    34  }
    35  
    36  // When reading export data it's possible to encounter a defined type
    37  // N1 with an underlying defined type N2 while we are still reading in
    38  // that defined type N2; see issues #29006 and #29198 for instances
    39  // of this. Example:
    40  //
    41  //   type N1 N2
    42  //   type N2 struct {
    43  //      ...
    44  //      p *N1
    45  //   }
    46  //
    47  // To handle such cases, the parser generates a fixup record (below) and
    48  // delays setting of N1's underlying type until parsing is complete, at
    49  // which point fixups are applied.
    50  
    51  type fixupRecord struct {
    52  	toUpdate *types.Named // type to modify when fixup is processed
    53  	target   types.Type   // type that was incomplete when fixup was created
    54  }
    55  
    56  func (p *parser) init(filename string, src io.Reader, imports map[string]*types.Package) {
    57  	p.scanner = new(scanner.Scanner)
    58  	p.initScanner(filename, src)
    59  	p.imports = imports
    60  	p.aliases = make(map[int]string)
    61  	p.typeList = make([]types.Type, 1 /* type numbers start at 1 */, 16)
    62  }
    63  
    64  func (p *parser) initScanner(filename string, src io.Reader) {
    65  	p.scanner.Init(src)
    66  	p.scanner.Error = func(_ *scanner.Scanner, msg string) { p.error(msg) }
    67  	p.scanner.Mode = scanner.ScanIdents | scanner.ScanInts | scanner.ScanFloats | scanner.ScanStrings
    68  	p.scanner.Whitespace = 1<<'\t' | 1<<' '
    69  	p.scanner.Filename = filename // for good error messages
    70  	p.next()
    71  }
    72  
    73  type importError struct {
    74  	pos scanner.Position
    75  	err error
    76  }
    77  
    78  var _ error = importError{}
    79  
    80  func (e importError) Error() string {
    81  	return fmt.Sprintf("import error %s (byte offset = %d): %s", e.pos, e.pos.Offset, e.err)
    82  }
    83  
    84  func (p *parser) error(err any) {
    85  	if s, ok := err.(string); ok {
    86  		err = errors.New(s)
    87  	}
    88  	// panic with a runtime.Error if err is not an error
    89  	panic(importError{p.scanner.Pos(), err.(error)})
    90  }
    91  
    92  func (p *parser) errorf(format string, args ...any) {
    93  	p.error(fmt.Errorf(format, args...))
    94  }
    95  
    96  func (p *parser) expect(tok rune) string {
    97  	lit := p.lit
    98  	if p.tok != tok {
    99  		p.errorf("expected %s, got %s (%s)", scanner.TokenString(tok), scanner.TokenString(p.tok), lit)
   100  	}
   101  	p.next()
   102  	return lit
   103  }
   104  
   105  func (p *parser) expectEOL() {
   106  	if p.version == "v1" || p.version == "v2" {
   107  		p.expect(';')
   108  	}
   109  	p.expect('\n')
   110  }
   111  
   112  func (p *parser) expectKeyword(keyword string) {
   113  	lit := p.expect(scanner.Ident)
   114  	if lit != keyword {
   115  		p.errorf("expected keyword %s, got %q", keyword, lit)
   116  	}
   117  }
   118  
   119  func (p *parser) parseString() string {
   120  	str, err := strconv.Unquote(p.expect(scanner.String))
   121  	if err != nil {
   122  		p.error(err)
   123  	}
   124  	return str
   125  }
   126  
   127  // unquotedString     = { unquotedStringChar } .
   128  // unquotedStringChar = <neither a whitespace nor a ';' char> .
   129  func (p *parser) parseUnquotedString() string {
   130  	if p.tok == scanner.EOF {
   131  		p.error("unexpected EOF")
   132  	}
   133  	var b strings.Builder
   134  	b.WriteString(p.scanner.TokenText())
   135  	// This loop needs to examine each character before deciding whether to consume it. If we see a semicolon,
   136  	// we need to let it be consumed by p.next().
   137  	for ch := p.scanner.Peek(); ch != '\n' && ch != ';' && ch != scanner.EOF && p.scanner.Whitespace&(1<<uint(ch)) == 0; ch = p.scanner.Peek() {
   138  		b.WriteRune(ch)
   139  		p.scanner.Next()
   140  	}
   141  	p.next()
   142  	return b.String()
   143  }
   144  
   145  func (p *parser) next() {
   146  	p.tok = p.scanner.Scan()
   147  	switch p.tok {
   148  	case scanner.Ident, scanner.Int, scanner.Float, scanner.String, '·':
   149  		p.lit = p.scanner.TokenText()
   150  	default:
   151  		p.lit = ""
   152  	}
   153  }
   154  
   155  func (p *parser) parseQualifiedName() (path, name string) {
   156  	return p.parseQualifiedNameStr(p.parseString())
   157  }
   158  
   159  func (p *parser) parseUnquotedQualifiedName() (path, name string) {
   160  	return p.parseQualifiedNameStr(p.parseUnquotedString())
   161  }
   162  
   163  // qualifiedName = [ ["."] unquotedString "." ] unquotedString .
   164  //
   165  // The above production uses greedy matching.
   166  func (p *parser) parseQualifiedNameStr(unquotedName string) (pkgpath, name string) {
   167  	parts := strings.Split(unquotedName, ".")
   168  	if parts[0] == "" {
   169  		parts = parts[1:]
   170  	}
   171  
   172  	switch len(parts) {
   173  	case 0:
   174  		p.errorf("malformed qualified name: %q", unquotedName)
   175  	case 1:
   176  		// unqualified name
   177  		pkgpath = p.pkgpath
   178  		name = parts[0]
   179  	default:
   180  		// qualified name, which may contain periods
   181  		pkgpath = strings.Join(parts[:len(parts)-1], ".")
   182  		name = parts[len(parts)-1]
   183  	}
   184  
   185  	return
   186  }
   187  
   188  // getPkg returns the package for a given path. If the package is
   189  // not found but we have a package name, create the package and
   190  // add it to the p.imports map.
   191  func (p *parser) getPkg(pkgpath, name string) *types.Package {
   192  	// package unsafe is not in the imports map - handle explicitly
   193  	if pkgpath == "unsafe" {
   194  		return types.Unsafe
   195  	}
   196  	pkg := p.imports[pkgpath]
   197  	if pkg == nil && name != "" {
   198  		pkg = types.NewPackage(pkgpath, name)
   199  		p.imports[pkgpath] = pkg
   200  	}
   201  	return pkg
   202  }
   203  
   204  // parseExportedName is like parseQualifiedName, but
   205  // the package path is resolved to an imported *types.Package.
   206  //
   207  // ExportedName = string [string] .
   208  func (p *parser) parseExportedName() (pkg *types.Package, name string) {
   209  	path, name := p.parseQualifiedName()
   210  	var pkgname string
   211  	if p.tok == scanner.String {
   212  		pkgname = p.parseString()
   213  	}
   214  	pkg = p.getPkg(path, pkgname)
   215  	if pkg == nil {
   216  		p.errorf("package %s (path = %q) not found", name, path)
   217  	}
   218  	return
   219  }
   220  
   221  // Name = QualifiedName | "?" .
   222  func (p *parser) parseName() string {
   223  	if p.tok == '?' {
   224  		// Anonymous.
   225  		p.next()
   226  		return ""
   227  	}
   228  	// The package path is redundant for us. Don't try to parse it.
   229  	_, name := p.parseUnquotedQualifiedName()
   230  	return name
   231  }
   232  
   233  func deref(typ types.Type) types.Type {
   234  	if p, _ := typ.(*types.Pointer); p != nil {
   235  		typ = p.Elem()
   236  	}
   237  	return typ
   238  }
   239  
   240  // Field = Name Type [string] .
   241  func (p *parser) parseField(pkg *types.Package) (field *types.Var, tag string) {
   242  	name := p.parseName()
   243  	typ, n := p.parseTypeExtended(pkg)
   244  	anon := false
   245  	if name == "" {
   246  		anon = true
   247  		// Alias?
   248  		if aname, ok := p.aliases[n]; ok {
   249  			name = aname
   250  		} else {
   251  			switch typ := deref(typ).(type) {
   252  			case *types.Basic:
   253  				name = typ.Name()
   254  			case *types.Named:
   255  				name = typ.Obj().Name()
   256  			default:
   257  				p.error("embedded field expected")
   258  			}
   259  		}
   260  	}
   261  	field = types.NewField(token.NoPos, pkg, name, typ, anon)
   262  	if p.tok == scanner.String {
   263  		tag = p.parseString()
   264  	}
   265  	return
   266  }
   267  
   268  // Param = Name ["..."] Type .
   269  func (p *parser) parseParam(kind types.VarKind, pkg *types.Package) (param *types.Var, isVariadic bool) {
   270  	name := p.parseName()
   271  	// Ignore names invented for inlinable functions.
   272  	if strings.HasPrefix(name, "p.") || strings.HasPrefix(name, "r.") || strings.HasPrefix(name, "$ret") {
   273  		name = ""
   274  	}
   275  	if p.tok == '<' && p.scanner.Peek() == 'e' {
   276  		// EscInfo = "<esc:" int ">" . (optional and ignored)
   277  		p.next()
   278  		p.expectKeyword("esc")
   279  		p.expect(':')
   280  		p.expect(scanner.Int)
   281  		p.expect('>')
   282  	}
   283  	if p.tok == '.' {
   284  		p.next()
   285  		p.expect('.')
   286  		p.expect('.')
   287  		isVariadic = true
   288  	}
   289  	typ := p.parseType(pkg)
   290  	if isVariadic {
   291  		typ = types.NewSlice(typ)
   292  	}
   293  	param = types.NewParam(token.NoPos, pkg, name, typ)
   294  	param.SetKind(kind)
   295  	return
   296  }
   297  
   298  // Var = Name Type .
   299  func (p *parser) parseVar(pkg *types.Package) *types.Var {
   300  	name := p.parseName()
   301  	v := types.NewVar(token.NoPos, pkg, name, p.parseType(pkg)) // (types.PackageVar)
   302  	if name[0] == '.' || name[0] == '<' {
   303  		// This is an unexported variable,
   304  		// or a variable defined in a different package.
   305  		// We only want to record exported variables.
   306  		return nil
   307  	}
   308  	return v
   309  }
   310  
   311  // Conversion = "convert" "(" Type "," ConstValue ")" .
   312  func (p *parser) parseConversion(pkg *types.Package) (val constant.Value, typ types.Type) {
   313  	p.expectKeyword("convert")
   314  	p.expect('(')
   315  	typ = p.parseType(pkg)
   316  	p.expect(',')
   317  	val, _ = p.parseConstValue(pkg)
   318  	p.expect(')')
   319  	return
   320  }
   321  
   322  // ConstValue     = string | "false" | "true" | ["-"] (int ["'"] | FloatOrComplex) | Conversion .
   323  // FloatOrComplex = float ["i" | ("+"|"-") float "i"] .
   324  func (p *parser) parseConstValue(pkg *types.Package) (val constant.Value, typ types.Type) {
   325  	// v3 changed to $false, $true, $convert, to avoid confusion
   326  	// with variable names in inline function bodies.
   327  	if p.tok == '$' {
   328  		p.next()
   329  		if p.tok != scanner.Ident {
   330  			p.errorf("expected identifier after '$', got %s (%q)", scanner.TokenString(p.tok), p.lit)
   331  		}
   332  	}
   333  
   334  	switch p.tok {
   335  	case scanner.String:
   336  		str := p.parseString()
   337  		val = constant.MakeString(str)
   338  		typ = types.Typ[types.UntypedString]
   339  		return
   340  
   341  	case scanner.Ident:
   342  		b := false
   343  		switch p.lit {
   344  		case "false":
   345  		case "true":
   346  			b = true
   347  
   348  		case "convert":
   349  			return p.parseConversion(pkg)
   350  
   351  		default:
   352  			p.errorf("expected const value, got %s (%q)", scanner.TokenString(p.tok), p.lit)
   353  		}
   354  
   355  		p.next()
   356  		val = constant.MakeBool(b)
   357  		typ = types.Typ[types.UntypedBool]
   358  		return
   359  	}
   360  
   361  	sign := ""
   362  	if p.tok == '-' {
   363  		p.next()
   364  		sign = "-"
   365  	}
   366  
   367  	switch p.tok {
   368  	case scanner.Int:
   369  		val = constant.MakeFromLiteral(sign+p.lit, token.INT, 0)
   370  		if val == nil {
   371  			p.error("could not parse integer literal")
   372  		}
   373  
   374  		p.next()
   375  		if p.tok == '\'' {
   376  			p.next()
   377  			typ = types.Typ[types.UntypedRune]
   378  		} else {
   379  			typ = types.Typ[types.UntypedInt]
   380  		}
   381  
   382  	case scanner.Float:
   383  		re := sign + p.lit
   384  		p.next()
   385  
   386  		var im string
   387  		switch p.tok {
   388  		case '+':
   389  			p.next()
   390  			im = p.expect(scanner.Float)
   391  
   392  		case '-':
   393  			p.next()
   394  			im = "-" + p.expect(scanner.Float)
   395  
   396  		case scanner.Ident:
   397  			// re is in fact the imaginary component. Expect "i" below.
   398  			im = re
   399  			re = "0"
   400  
   401  		default:
   402  			val = constant.MakeFromLiteral(re, token.FLOAT, 0)
   403  			if val == nil {
   404  				p.error("could not parse float literal")
   405  			}
   406  			typ = types.Typ[types.UntypedFloat]
   407  			return
   408  		}
   409  
   410  		p.expectKeyword("i")
   411  		reval := constant.MakeFromLiteral(re, token.FLOAT, 0)
   412  		if reval == nil {
   413  			p.error("could not parse real component of complex literal")
   414  		}
   415  		imval := constant.MakeFromLiteral(im+"i", token.IMAG, 0)
   416  		if imval == nil {
   417  			p.error("could not parse imag component of complex literal")
   418  		}
   419  		val = constant.BinaryOp(reval, token.ADD, imval)
   420  		typ = types.Typ[types.UntypedComplex]
   421  
   422  	default:
   423  		p.errorf("expected const value, got %s (%q)", scanner.TokenString(p.tok), p.lit)
   424  	}
   425  
   426  	return
   427  }
   428  
   429  // Const = Name [Type] "=" ConstValue .
   430  func (p *parser) parseConst(pkg *types.Package) *types.Const {
   431  	name := p.parseName()
   432  	var typ types.Type
   433  	if p.tok == '<' {
   434  		typ = p.parseType(pkg)
   435  	}
   436  	p.expect('=')
   437  	val, vtyp := p.parseConstValue(pkg)
   438  	if typ == nil {
   439  		typ = vtyp
   440  	}
   441  	return types.NewConst(token.NoPos, pkg, name, typ, val)
   442  }
   443  
   444  // reserved is a singleton type used to fill type map slots that have
   445  // been reserved (i.e., for which a type number has been parsed) but
   446  // which don't have their actual type yet. When the type map is updated,
   447  // the actual type must replace a reserved entry (or we have an internal
   448  // error). Used for self-verification only - not required for correctness.
   449  var reserved = new(struct{ types.Type })
   450  
   451  // reserve reserves the type map entry n for future use.
   452  func (p *parser) reserve(n int) {
   453  	// Notes:
   454  	// - for pre-V3 export data, the type numbers we see are
   455  	//   guaranteed to be in increasing order, so we append a
   456  	//   reserved entry onto the list.
   457  	// - for V3+ export data, type numbers can appear in
   458  	//   any order, however the 'types' section tells us the
   459  	//   total number of types, hence typeList is pre-allocated.
   460  	if len(p.typeData) == 0 {
   461  		if n != len(p.typeList) {
   462  			p.errorf("invalid type number %d (out of sync)", n)
   463  		}
   464  		p.typeList = append(p.typeList, reserved)
   465  	} else {
   466  		if p.typeList[n] != nil {
   467  			p.errorf("previously visited type number %d", n)
   468  		}
   469  		p.typeList[n] = reserved
   470  	}
   471  }
   472  
   473  // update sets the type map entries for the entries in nlist to t.
   474  // An entry in nlist can be a type number in p.typeList,
   475  // used to resolve named types, or it can be a *types.Pointer,
   476  // used to resolve pointers to named types in case they are referenced
   477  // by embedded fields.
   478  func (p *parser) update(t types.Type, nlist []any) {
   479  	if t == reserved {
   480  		p.errorf("internal error: update(%v) invoked on reserved", nlist)
   481  	}
   482  	if t == nil {
   483  		p.errorf("internal error: update(%v) invoked on nil", nlist)
   484  	}
   485  	for _, n := range nlist {
   486  		switch n := n.(type) {
   487  		case int:
   488  			if p.typeList[n] == t {
   489  				continue
   490  			}
   491  			if p.typeList[n] != reserved {
   492  				p.errorf("internal error: update(%v): %d not reserved", nlist, n)
   493  			}
   494  			p.typeList[n] = t
   495  		case *types.Pointer:
   496  			if *n != (types.Pointer{}) {
   497  				elem := n.Elem()
   498  				if elem == t {
   499  					continue
   500  				}
   501  				p.errorf("internal error: update: pointer already set to %v, expected %v", elem, t)
   502  			}
   503  			*n = *types.NewPointer(t)
   504  		default:
   505  			p.errorf("internal error: %T on nlist", n)
   506  		}
   507  	}
   508  }
   509  
   510  // NamedType = TypeName [ "=" ] Type { Method } .
   511  // TypeName  = ExportedName .
   512  // Method    = "func" "(" Param ")" Name ParamList ResultList [InlineBody] ";" .
   513  func (p *parser) parseNamedType(nlist []any) types.Type {
   514  	pkg, name := p.parseExportedName()
   515  	scope := pkg.Scope()
   516  	obj := scope.Lookup(name)
   517  	if obj != nil && obj.Type() == nil {
   518  		p.errorf("%v has nil type", obj)
   519  	}
   520  
   521  	if p.tok == scanner.Ident && p.lit == "notinheap" {
   522  		p.next()
   523  		// The go/types package has no way of recording that
   524  		// this type is marked notinheap. Presumably no user
   525  		// of this package actually cares.
   526  	}
   527  
   528  	// type alias
   529  	if p.tok == '=' {
   530  		p.next()
   531  		p.aliases[nlist[len(nlist)-1].(int)] = name
   532  		if obj != nil {
   533  			// use the previously imported (canonical) type
   534  			t := obj.Type()
   535  			p.update(t, nlist)
   536  			p.parseType(pkg) // discard
   537  			return t
   538  		}
   539  		t := p.parseType(pkg, nlist...)
   540  		obj = types.NewTypeName(token.NoPos, pkg, name, t)
   541  		scope.Insert(obj)
   542  		return t
   543  	}
   544  
   545  	// defined type
   546  	if obj == nil {
   547  		// A named type may be referred to before the underlying type
   548  		// is known - set it up.
   549  		tname := types.NewTypeName(token.NoPos, pkg, name, nil)
   550  		types.NewNamed(tname, nil, nil)
   551  		scope.Insert(tname)
   552  		obj = tname
   553  	}
   554  
   555  	// use the previously imported (canonical), or newly created type
   556  	t := obj.Type()
   557  	p.update(t, nlist)
   558  
   559  	nt, ok := t.(*types.Named)
   560  	if !ok {
   561  		// This can happen for unsafe.Pointer, which is a TypeName holding a Basic type.
   562  		pt := p.parseType(pkg)
   563  		if pt != t {
   564  			p.error("unexpected underlying type for non-named TypeName")
   565  		}
   566  		return t
   567  	}
   568  
   569  	underlying := p.parseType(pkg)
   570  	if nt.Underlying() == nil {
   571  		if underlying.Underlying() == nil {
   572  			fix := fixupRecord{toUpdate: nt, target: underlying}
   573  			p.fixups = append(p.fixups, fix)
   574  		} else {
   575  			nt.SetUnderlying(underlying.Underlying())
   576  		}
   577  	}
   578  
   579  	if p.tok == '\n' {
   580  		p.next()
   581  		// collect associated methods
   582  		for p.tok == scanner.Ident {
   583  			p.expectKeyword("func")
   584  			if p.tok == '/' {
   585  				// Skip a /*nointerface*/ or /*asm ID */ comment.
   586  				p.expect('/')
   587  				p.expect('*')
   588  				if p.expect(scanner.Ident) == "asm" {
   589  					p.parseUnquotedString()
   590  				}
   591  				p.expect('*')
   592  				p.expect('/')
   593  			}
   594  			p.expect('(')
   595  			receiver, _ := p.parseParam(types.RecvVar, pkg)
   596  			p.expect(')')
   597  			name := p.parseName()
   598  			params, isVariadic := p.parseParamList(types.ParamVar, pkg)
   599  			results := p.parseResultList(pkg)
   600  			p.skipInlineBody()
   601  			p.expectEOL()
   602  
   603  			sig := types.NewSignatureType(receiver, nil, nil, params, results, isVariadic)
   604  			nt.AddMethod(types.NewFunc(token.NoPos, pkg, name, sig))
   605  		}
   606  	}
   607  
   608  	return nt
   609  }
   610  
   611  func (p *parser) parseInt64() int64 {
   612  	lit := p.expect(scanner.Int)
   613  	n, err := strconv.ParseInt(lit, 10, 64)
   614  	if err != nil {
   615  		p.error(err)
   616  	}
   617  	return n
   618  }
   619  
   620  func (p *parser) parseInt() int {
   621  	lit := p.expect(scanner.Int)
   622  	n, err := strconv.ParseInt(lit, 10, 0 /* int */)
   623  	if err != nil {
   624  		p.error(err)
   625  	}
   626  	return int(n)
   627  }
   628  
   629  // ArrayOrSliceType = "[" [ int ] "]" Type .
   630  func (p *parser) parseArrayOrSliceType(pkg *types.Package, nlist []any) types.Type {
   631  	p.expect('[')
   632  	if p.tok == ']' {
   633  		p.next()
   634  
   635  		t := new(types.Slice)
   636  		p.update(t, nlist)
   637  
   638  		*t = *types.NewSlice(p.parseType(pkg))
   639  		return t
   640  	}
   641  
   642  	t := new(types.Array)
   643  	p.update(t, nlist)
   644  
   645  	len := p.parseInt64()
   646  	p.expect(']')
   647  
   648  	*t = *types.NewArray(p.parseType(pkg), len)
   649  	return t
   650  }
   651  
   652  // MapType = "map" "[" Type "]" Type .
   653  func (p *parser) parseMapType(pkg *types.Package, nlist []any) types.Type {
   654  	p.expectKeyword("map")
   655  
   656  	t := new(types.Map)
   657  	p.update(t, nlist)
   658  
   659  	p.expect('[')
   660  	key := p.parseType(pkg)
   661  	p.expect(']')
   662  	elem := p.parseType(pkg)
   663  
   664  	*t = *types.NewMap(key, elem)
   665  	return t
   666  }
   667  
   668  // ChanType = "chan" ["<-" | "-<"] Type .
   669  func (p *parser) parseChanType(pkg *types.Package, nlist []any) types.Type {
   670  	p.expectKeyword("chan")
   671  
   672  	t := new(types.Chan)
   673  	p.update(t, nlist)
   674  
   675  	dir := types.SendRecv
   676  	switch p.tok {
   677  	case '-':
   678  		p.next()
   679  		p.expect('<')
   680  		dir = types.SendOnly
   681  
   682  	case '<':
   683  		// don't consume '<' if it belongs to Type
   684  		if p.scanner.Peek() == '-' {
   685  			p.next()
   686  			p.expect('-')
   687  			dir = types.RecvOnly
   688  		}
   689  	}
   690  
   691  	*t = *types.NewChan(dir, p.parseType(pkg))
   692  	return t
   693  }
   694  
   695  // StructType = "struct" "{" { Field } "}" .
   696  func (p *parser) parseStructType(pkg *types.Package, nlist []any) types.Type {
   697  	p.expectKeyword("struct")
   698  
   699  	t := new(types.Struct)
   700  	p.update(t, nlist)
   701  
   702  	var fields []*types.Var
   703  	var tags []string
   704  
   705  	p.expect('{')
   706  	for p.tok != '}' && p.tok != scanner.EOF {
   707  		field, tag := p.parseField(pkg)
   708  		p.expect(';')
   709  		fields = append(fields, field)
   710  		tags = append(tags, tag)
   711  	}
   712  	p.expect('}')
   713  
   714  	*t = *types.NewStruct(fields, tags)
   715  	return t
   716  }
   717  
   718  // ParamList = "(" [ { Parameter "," } Parameter ] ")" .
   719  func (p *parser) parseParamList(kind types.VarKind, pkg *types.Package) (*types.Tuple, bool) {
   720  	var list []*types.Var
   721  	isVariadic := false
   722  
   723  	p.expect('(')
   724  	for p.tok != ')' && p.tok != scanner.EOF {
   725  		if len(list) > 0 {
   726  			p.expect(',')
   727  		}
   728  		par, variadic := p.parseParam(kind, pkg)
   729  		list = append(list, par)
   730  		if variadic {
   731  			if isVariadic {
   732  				p.error("... not on final argument")
   733  			}
   734  			isVariadic = true
   735  		}
   736  	}
   737  	p.expect(')')
   738  
   739  	return types.NewTuple(list...), isVariadic
   740  }
   741  
   742  // ResultList = Type | ParamList .
   743  func (p *parser) parseResultList(pkg *types.Package) *types.Tuple {
   744  	switch p.tok {
   745  	case '<':
   746  		p.next()
   747  		if p.tok == scanner.Ident && p.lit == "inl" {
   748  			return nil
   749  		}
   750  		taa, _ := p.parseTypeAfterAngle(pkg)
   751  		param := types.NewParam(token.NoPos, pkg, "", taa)
   752  		param.SetKind(types.ResultVar)
   753  		return types.NewTuple(param)
   754  
   755  	case '(':
   756  		params, _ := p.parseParamList(types.ResultVar, pkg)
   757  		return params
   758  
   759  	default:
   760  		return nil
   761  	}
   762  }
   763  
   764  // FunctionType = ParamList ResultList .
   765  func (p *parser) parseFunctionType(pkg *types.Package, nlist []any) *types.Signature {
   766  	t := new(types.Signature)
   767  	p.update(t, nlist)
   768  
   769  	params, isVariadic := p.parseParamList(types.ParamVar, pkg)
   770  	results := p.parseResultList(pkg)
   771  
   772  	*t = *types.NewSignatureType(nil, nil, nil, params, results, isVariadic)
   773  	return t
   774  }
   775  
   776  // Func = Name FunctionType [InlineBody] .
   777  func (p *parser) parseFunc(pkg *types.Package) *types.Func {
   778  	if p.tok == '/' {
   779  		// Skip an /*asm ID */ comment.
   780  		p.expect('/')
   781  		p.expect('*')
   782  		if p.expect(scanner.Ident) == "asm" {
   783  			p.parseUnquotedString()
   784  		}
   785  		p.expect('*')
   786  		p.expect('/')
   787  	}
   788  
   789  	name := p.parseName()
   790  	f := types.NewFunc(token.NoPos, pkg, name, p.parseFunctionType(pkg, nil))
   791  	p.skipInlineBody()
   792  
   793  	if name[0] == '.' || name[0] == '<' || strings.ContainsRune(name, '$') {
   794  		// This is an unexported function,
   795  		// or a function defined in a different package,
   796  		// or a type$equal or type$hash function.
   797  		// We only want to record exported functions.
   798  		return nil
   799  	}
   800  
   801  	return f
   802  }
   803  
   804  // InterfaceType = "interface" "{" { ("?" Type | Func) ";" } "}" .
   805  func (p *parser) parseInterfaceType(pkg *types.Package, nlist []any) types.Type {
   806  	p.expectKeyword("interface")
   807  
   808  	t := new(types.Interface)
   809  	p.update(t, nlist)
   810  
   811  	var methods []*types.Func
   812  	var embeddeds []types.Type
   813  
   814  	p.expect('{')
   815  	for p.tok != '}' && p.tok != scanner.EOF {
   816  		if p.tok == '?' {
   817  			p.next()
   818  			embeddeds = append(embeddeds, p.parseType(pkg))
   819  		} else {
   820  			method := p.parseFunc(pkg)
   821  			if method != nil {
   822  				methods = append(methods, method)
   823  			}
   824  		}
   825  		p.expect(';')
   826  	}
   827  	p.expect('}')
   828  
   829  	*t = *types.NewInterfaceType(methods, embeddeds)
   830  	return t
   831  }
   832  
   833  // PointerType = "*" ("any" | Type) .
   834  func (p *parser) parsePointerType(pkg *types.Package, nlist []any) types.Type {
   835  	p.expect('*')
   836  	if p.tok == scanner.Ident {
   837  		p.expectKeyword("any")
   838  		t := types.Typ[types.UnsafePointer]
   839  		p.update(t, nlist)
   840  		return t
   841  	}
   842  
   843  	t := new(types.Pointer)
   844  	p.update(t, nlist)
   845  
   846  	*t = *types.NewPointer(p.parseType(pkg, t))
   847  
   848  	return t
   849  }
   850  
   851  // TypeSpec = NamedType | MapType | ChanType | StructType | InterfaceType | PointerType | ArrayOrSliceType | FunctionType .
   852  func (p *parser) parseTypeSpec(pkg *types.Package, nlist []any) types.Type {
   853  	switch p.tok {
   854  	case scanner.String:
   855  		return p.parseNamedType(nlist)
   856  
   857  	case scanner.Ident:
   858  		switch p.lit {
   859  		case "map":
   860  			return p.parseMapType(pkg, nlist)
   861  
   862  		case "chan":
   863  			return p.parseChanType(pkg, nlist)
   864  
   865  		case "struct":
   866  			return p.parseStructType(pkg, nlist)
   867  
   868  		case "interface":
   869  			return p.parseInterfaceType(pkg, nlist)
   870  		}
   871  
   872  	case '*':
   873  		return p.parsePointerType(pkg, nlist)
   874  
   875  	case '[':
   876  		return p.parseArrayOrSliceType(pkg, nlist)
   877  
   878  	case '(':
   879  		return p.parseFunctionType(pkg, nlist)
   880  	}
   881  
   882  	p.errorf("expected type name or literal, got %s", scanner.TokenString(p.tok))
   883  	return nil
   884  }
   885  
   886  const (
   887  	// From gofrontend/go/export.h
   888  	// Note that these values are negative in the gofrontend and have been made positive
   889  	// in the gccgoimporter.
   890  	gccgoBuiltinINT8       = 1
   891  	gccgoBuiltinINT16      = 2
   892  	gccgoBuiltinINT32      = 3
   893  	gccgoBuiltinINT64      = 4
   894  	gccgoBuiltinUINT8      = 5
   895  	gccgoBuiltinUINT16     = 6
   896  	gccgoBuiltinUINT32     = 7
   897  	gccgoBuiltinUINT64     = 8
   898  	gccgoBuiltinFLOAT32    = 9
   899  	gccgoBuiltinFLOAT64    = 10
   900  	gccgoBuiltinINT        = 11
   901  	gccgoBuiltinUINT       = 12
   902  	gccgoBuiltinUINTPTR    = 13
   903  	gccgoBuiltinBOOL       = 15
   904  	gccgoBuiltinSTRING     = 16
   905  	gccgoBuiltinCOMPLEX64  = 17
   906  	gccgoBuiltinCOMPLEX128 = 18
   907  	gccgoBuiltinERROR      = 19
   908  	gccgoBuiltinBYTE       = 20
   909  	gccgoBuiltinRUNE       = 21
   910  	gccgoBuiltinANY        = 22
   911  )
   912  
   913  func lookupBuiltinType(typ int) types.Type {
   914  	return [...]types.Type{
   915  		gccgoBuiltinINT8:       types.Typ[types.Int8],
   916  		gccgoBuiltinINT16:      types.Typ[types.Int16],
   917  		gccgoBuiltinINT32:      types.Typ[types.Int32],
   918  		gccgoBuiltinINT64:      types.Typ[types.Int64],
   919  		gccgoBuiltinUINT8:      types.Typ[types.Uint8],
   920  		gccgoBuiltinUINT16:     types.Typ[types.Uint16],
   921  		gccgoBuiltinUINT32:     types.Typ[types.Uint32],
   922  		gccgoBuiltinUINT64:     types.Typ[types.Uint64],
   923  		gccgoBuiltinFLOAT32:    types.Typ[types.Float32],
   924  		gccgoBuiltinFLOAT64:    types.Typ[types.Float64],
   925  		gccgoBuiltinINT:        types.Typ[types.Int],
   926  		gccgoBuiltinUINT:       types.Typ[types.Uint],
   927  		gccgoBuiltinUINTPTR:    types.Typ[types.Uintptr],
   928  		gccgoBuiltinBOOL:       types.Typ[types.Bool],
   929  		gccgoBuiltinSTRING:     types.Typ[types.String],
   930  		gccgoBuiltinCOMPLEX64:  types.Typ[types.Complex64],
   931  		gccgoBuiltinCOMPLEX128: types.Typ[types.Complex128],
   932  		gccgoBuiltinERROR:      types.Universe.Lookup("error").Type(),
   933  		gccgoBuiltinBYTE:       types.Universe.Lookup("byte").Type(),
   934  		gccgoBuiltinRUNE:       types.Universe.Lookup("rune").Type(),
   935  		gccgoBuiltinANY:        types.Universe.Lookup("any").Type(),
   936  	}[typ]
   937  }
   938  
   939  // Type = "<" "type" ( "-" int | int [ TypeSpec ] ) ">" .
   940  //
   941  // parseType updates the type map to t for all type numbers n.
   942  func (p *parser) parseType(pkg *types.Package, n ...any) types.Type {
   943  	p.expect('<')
   944  	t, _ := p.parseTypeAfterAngle(pkg, n...)
   945  	return t
   946  }
   947  
   948  // (*parser).Type after reading the "<".
   949  func (p *parser) parseTypeAfterAngle(pkg *types.Package, n ...any) (t types.Type, n1 int) {
   950  	p.expectKeyword("type")
   951  
   952  	n1 = 0
   953  	switch p.tok {
   954  	case scanner.Int:
   955  		n1 = p.parseInt()
   956  		if p.tok == '>' {
   957  			if len(p.typeData) > 0 && p.typeList[n1] == nil {
   958  				p.parseSavedType(pkg, n1, n)
   959  			}
   960  			t = p.typeList[n1]
   961  			if len(p.typeData) == 0 && t == reserved {
   962  				p.errorf("invalid type cycle, type %d not yet defined (nlist=%v)", n1, n)
   963  			}
   964  			p.update(t, n)
   965  		} else {
   966  			p.reserve(n1)
   967  			t = p.parseTypeSpec(pkg, append(n, n1))
   968  		}
   969  
   970  	case '-':
   971  		p.next()
   972  		n1 := p.parseInt()
   973  		t = lookupBuiltinType(n1)
   974  		p.update(t, n)
   975  
   976  	default:
   977  		p.errorf("expected type number, got %s (%q)", scanner.TokenString(p.tok), p.lit)
   978  		return nil, 0
   979  	}
   980  
   981  	if t == nil || t == reserved {
   982  		p.errorf("internal error: bad return from parseType(%v)", n)
   983  	}
   984  
   985  	p.expect('>')
   986  	return
   987  }
   988  
   989  // parseTypeExtended is identical to parseType, but if the type in
   990  // question is a saved type, returns the index as well as the type
   991  // pointer (index returned is zero if we parsed a builtin).
   992  func (p *parser) parseTypeExtended(pkg *types.Package, n ...any) (t types.Type, n1 int) {
   993  	p.expect('<')
   994  	t, n1 = p.parseTypeAfterAngle(pkg, n...)
   995  	return
   996  }
   997  
   998  // InlineBody = "<inl:NN>" .{NN}
   999  // Reports whether a body was skipped.
  1000  func (p *parser) skipInlineBody() {
  1001  	// We may or may not have seen the '<' already, depending on
  1002  	// whether the function had a result type or not.
  1003  	if p.tok == '<' {
  1004  		p.next()
  1005  		p.expectKeyword("inl")
  1006  	} else if p.tok != scanner.Ident || p.lit != "inl" {
  1007  		return
  1008  	} else {
  1009  		p.next()
  1010  	}
  1011  
  1012  	p.expect(':')
  1013  	want := p.parseInt()
  1014  	p.expect('>')
  1015  
  1016  	defer func(w uint64) {
  1017  		p.scanner.Whitespace = w
  1018  	}(p.scanner.Whitespace)
  1019  	p.scanner.Whitespace = 0
  1020  
  1021  	got := 0
  1022  	for got < want {
  1023  		r := p.scanner.Next()
  1024  		if r == scanner.EOF {
  1025  			p.error("unexpected EOF")
  1026  		}
  1027  		got += utf8.RuneLen(r)
  1028  	}
  1029  }
  1030  
  1031  // Types = "types" maxp1 exportedp1 (offset length)* .
  1032  func (p *parser) parseTypes(pkg *types.Package) {
  1033  	maxp1 := p.parseInt()
  1034  	exportedp1 := p.parseInt()
  1035  	p.typeList = make([]types.Type, maxp1, maxp1)
  1036  
  1037  	type typeOffset struct {
  1038  		offset int
  1039  		length int
  1040  	}
  1041  	var typeOffsets []typeOffset
  1042  
  1043  	total := 0
  1044  	for i := 1; i < maxp1; i++ {
  1045  		len := p.parseInt()
  1046  		typeOffsets = append(typeOffsets, typeOffset{total, len})
  1047  		total += len
  1048  	}
  1049  
  1050  	defer func(w uint64) {
  1051  		p.scanner.Whitespace = w
  1052  	}(p.scanner.Whitespace)
  1053  	p.scanner.Whitespace = 0
  1054  
  1055  	// We should now have p.tok pointing to the final newline.
  1056  	// The next runes from the scanner should be the type data.
  1057  
  1058  	var sb strings.Builder
  1059  	for sb.Len() < total {
  1060  		r := p.scanner.Next()
  1061  		if r == scanner.EOF {
  1062  			p.error("unexpected EOF")
  1063  		}
  1064  		sb.WriteRune(r)
  1065  	}
  1066  	allTypeData := sb.String()
  1067  
  1068  	p.typeData = []string{""} // type 0, unused
  1069  	for _, to := range typeOffsets {
  1070  		p.typeData = append(p.typeData, allTypeData[to.offset:to.offset+to.length])
  1071  	}
  1072  
  1073  	for i := 1; i < exportedp1; i++ {
  1074  		p.parseSavedType(pkg, i, nil)
  1075  	}
  1076  }
  1077  
  1078  // parseSavedType parses one saved type definition.
  1079  func (p *parser) parseSavedType(pkg *types.Package, i int, nlist []any) {
  1080  	defer func(s *scanner.Scanner, tok rune, lit string) {
  1081  		p.scanner = s
  1082  		p.tok = tok
  1083  		p.lit = lit
  1084  	}(p.scanner, p.tok, p.lit)
  1085  
  1086  	p.scanner = new(scanner.Scanner)
  1087  	p.initScanner(p.scanner.Filename, strings.NewReader(p.typeData[i]))
  1088  	p.expectKeyword("type")
  1089  	id := p.parseInt()
  1090  	if id != i {
  1091  		p.errorf("type ID mismatch: got %d, want %d", id, i)
  1092  	}
  1093  	if p.typeList[i] == reserved {
  1094  		p.errorf("internal error: %d already reserved in parseSavedType", i)
  1095  	}
  1096  	if p.typeList[i] == nil {
  1097  		p.reserve(i)
  1098  		p.parseTypeSpec(pkg, append(nlist, i))
  1099  	}
  1100  	if p.typeList[i] == nil || p.typeList[i] == reserved {
  1101  		p.errorf("internal error: parseSavedType(%d,%v) reserved/nil", i, nlist)
  1102  	}
  1103  }
  1104  
  1105  // PackageInit = unquotedString unquotedString int .
  1106  func (p *parser) parsePackageInit() PackageInit {
  1107  	name := p.parseUnquotedString()
  1108  	initfunc := p.parseUnquotedString()
  1109  	priority := -1
  1110  	if p.version == "v1" {
  1111  		priority = p.parseInt()
  1112  	}
  1113  	return PackageInit{Name: name, InitFunc: initfunc, Priority: priority}
  1114  }
  1115  
  1116  // Create the package if we have parsed both the package path and package name.
  1117  func (p *parser) maybeCreatePackage() {
  1118  	if p.pkgname != "" && p.pkgpath != "" {
  1119  		p.pkg = p.getPkg(p.pkgpath, p.pkgname)
  1120  	}
  1121  }
  1122  
  1123  // InitDataDirective = ( "v1" | "v2" | "v3" ) ";" |
  1124  //
  1125  //	"priority" int ";" |
  1126  //	"init" { PackageInit } ";" |
  1127  //	"checksum" unquotedString ";" .
  1128  func (p *parser) parseInitDataDirective() {
  1129  	if p.tok != scanner.Ident {
  1130  		// unexpected token kind; panic
  1131  		p.expect(scanner.Ident)
  1132  	}
  1133  
  1134  	switch p.lit {
  1135  	case "v1", "v2", "v3":
  1136  		p.version = p.lit
  1137  		p.next()
  1138  		p.expect(';')
  1139  		p.expect('\n')
  1140  
  1141  	case "priority":
  1142  		p.next()
  1143  		p.initdata.Priority = p.parseInt()
  1144  		p.expectEOL()
  1145  
  1146  	case "init":
  1147  		p.next()
  1148  		for p.tok != '\n' && p.tok != ';' && p.tok != scanner.EOF {
  1149  			p.initdata.Inits = append(p.initdata.Inits, p.parsePackageInit())
  1150  		}
  1151  		p.expectEOL()
  1152  
  1153  	case "init_graph":
  1154  		p.next()
  1155  		// The graph data is thrown away for now.
  1156  		for p.tok != '\n' && p.tok != ';' && p.tok != scanner.EOF {
  1157  			p.parseInt64()
  1158  			p.parseInt64()
  1159  		}
  1160  		p.expectEOL()
  1161  
  1162  	case "checksum":
  1163  		// Don't let the scanner try to parse the checksum as a number.
  1164  		defer func(mode uint) {
  1165  			p.scanner.Mode = mode
  1166  		}(p.scanner.Mode)
  1167  		p.scanner.Mode &^= scanner.ScanInts | scanner.ScanFloats
  1168  		p.next()
  1169  		p.parseUnquotedString()
  1170  		p.expectEOL()
  1171  
  1172  	default:
  1173  		p.errorf("unexpected identifier: %q", p.lit)
  1174  	}
  1175  }
  1176  
  1177  // Directive = InitDataDirective |
  1178  //
  1179  //	"package" unquotedString [ unquotedString ] [ unquotedString ] ";" |
  1180  //	"pkgpath" unquotedString ";" |
  1181  //	"prefix" unquotedString ";" |
  1182  //	"import" unquotedString unquotedString string ";" |
  1183  //	"indirectimport" unquotedString unquotedstring ";" |
  1184  //	"func" Func ";" |
  1185  //	"type" Type ";" |
  1186  //	"var" Var ";" |
  1187  //	"const" Const ";" .
  1188  func (p *parser) parseDirective() {
  1189  	if p.tok != scanner.Ident {
  1190  		// unexpected token kind; panic
  1191  		p.expect(scanner.Ident)
  1192  	}
  1193  
  1194  	switch p.lit {
  1195  	case "v1", "v2", "v3", "priority", "init", "init_graph", "checksum":
  1196  		p.parseInitDataDirective()
  1197  
  1198  	case "package":
  1199  		p.next()
  1200  		p.pkgname = p.parseUnquotedString()
  1201  		p.maybeCreatePackage()
  1202  		if p.version != "v1" && p.tok != '\n' && p.tok != ';' {
  1203  			p.parseUnquotedString()
  1204  			p.parseUnquotedString()
  1205  		}
  1206  		p.expectEOL()
  1207  
  1208  	case "pkgpath":
  1209  		p.next()
  1210  		p.pkgpath = p.parseUnquotedString()
  1211  		p.maybeCreatePackage()
  1212  		p.expectEOL()
  1213  
  1214  	case "prefix":
  1215  		p.next()
  1216  		p.pkgpath = p.parseUnquotedString()
  1217  		p.expectEOL()
  1218  
  1219  	case "import":
  1220  		p.next()
  1221  		pkgname := p.parseUnquotedString()
  1222  		pkgpath := p.parseUnquotedString()
  1223  		p.getPkg(pkgpath, pkgname)
  1224  		p.parseString()
  1225  		p.expectEOL()
  1226  
  1227  	case "indirectimport":
  1228  		p.next()
  1229  		pkgname := p.parseUnquotedString()
  1230  		pkgpath := p.parseUnquotedString()
  1231  		p.getPkg(pkgpath, pkgname)
  1232  		p.expectEOL()
  1233  
  1234  	case "types":
  1235  		p.next()
  1236  		p.parseTypes(p.pkg)
  1237  		p.expectEOL()
  1238  
  1239  	case "func":
  1240  		p.next()
  1241  		fun := p.parseFunc(p.pkg)
  1242  		if fun != nil {
  1243  			p.pkg.Scope().Insert(fun)
  1244  		}
  1245  		p.expectEOL()
  1246  
  1247  	case "type":
  1248  		p.next()
  1249  		p.parseType(p.pkg)
  1250  		p.expectEOL()
  1251  
  1252  	case "var":
  1253  		p.next()
  1254  		v := p.parseVar(p.pkg)
  1255  		if v != nil {
  1256  			p.pkg.Scope().Insert(v)
  1257  		}
  1258  		p.expectEOL()
  1259  
  1260  	case "const":
  1261  		p.next()
  1262  		c := p.parseConst(p.pkg)
  1263  		p.pkg.Scope().Insert(c)
  1264  		p.expectEOL()
  1265  
  1266  	default:
  1267  		p.errorf("unexpected identifier: %q", p.lit)
  1268  	}
  1269  }
  1270  
  1271  // Package = { Directive } .
  1272  func (p *parser) parsePackage() *types.Package {
  1273  	for p.tok != scanner.EOF {
  1274  		p.parseDirective()
  1275  	}
  1276  	for _, f := range p.fixups {
  1277  		if f.target.Underlying() == nil {
  1278  			p.errorf("internal error: fixup can't be applied, loop required")
  1279  		}
  1280  		f.toUpdate.SetUnderlying(f.target.Underlying())
  1281  	}
  1282  	p.fixups = nil
  1283  	for _, typ := range p.typeList {
  1284  		if it, ok := typ.(*types.Interface); ok {
  1285  			it.Complete()
  1286  		}
  1287  	}
  1288  	p.pkg.MarkComplete()
  1289  	return p.pkg
  1290  }
  1291  

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