bimport.go

Documentation: golang.org/x/tools/internal/gcimporter

     1  // Copyright 2015 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  // This file contains the remaining vestiges of
     6  // $GOROOT/src/go/internal/gcimporter/bimport.go.
     7  
     8  package gcimporter
     9  
    10  import (
    11  	"fmt"
    12  	"go/token"
    13  	"go/types"
    14  	"sync"
    15  )
    16  
    17  func errorf(format string, args ...interface{}) {
    18  	panic(fmt.Sprintf(format, args...))
    19  }
    20  
    21  const deltaNewFile = -64 // see cmd/compile/internal/gc/bexport.go
    22  
    23  // Synthesize a token.Pos
    24  type fakeFileSet struct {
    25  	fset  *token.FileSet
    26  	files map[string]*fileInfo
    27  }
    28  
    29  type fileInfo struct {
    30  	file     *token.File
    31  	lastline int
    32  }
    33  
    34  const maxlines = 64 * 1024
    35  
    36  func (s *fakeFileSet) pos(file string, line, column int) token.Pos {
    37  	// TODO(mdempsky): Make use of column.
    38  
    39  	// Since we don't know the set of needed file positions, we reserve maxlines
    40  	// positions per file. We delay calling token.File.SetLines until all
    41  	// positions have been calculated (by way of fakeFileSet.setLines), so that
    42  	// we can avoid setting unnecessary lines. See also golang/go#46586.
    43  	f := s.files[file]
    44  	if f == nil {
    45  		f = &fileInfo{file: s.fset.AddFile(file, -1, maxlines)}
    46  		s.files[file] = f
    47  	}
    48  	if line > maxlines {
    49  		line = 1
    50  	}
    51  	if line > f.lastline {
    52  		f.lastline = line
    53  	}
    54  
    55  	// Return a fake position assuming that f.file consists only of newlines.
    56  	return token.Pos(f.file.Base() + line - 1)
    57  }
    58  
    59  func (s *fakeFileSet) setLines() {
    60  	fakeLinesOnce.Do(func() {
    61  		fakeLines = make([]int, maxlines)
    62  		for i := range fakeLines {
    63  			fakeLines[i] = i
    64  		}
    65  	})
    66  	for _, f := range s.files {
    67  		f.file.SetLines(fakeLines[:f.lastline])
    68  	}
    69  }
    70  
    71  var (
    72  	fakeLines     []int
    73  	fakeLinesOnce sync.Once
    74  )
    75  
    76  func chanDir(d int) types.ChanDir {
    77  	// tag values must match the constants in cmd/compile/internal/gc/go.go
    78  	switch d {
    79  	case 1 /* Crecv */ :
    80  		return types.RecvOnly
    81  	case 2 /* Csend */ :
    82  		return types.SendOnly
    83  	case 3 /* Cboth */ :
    84  		return types.SendRecv
    85  	default:
    86  		errorf("unexpected channel dir %d", d)
    87  		return 0
    88  	}
    89  }
    90  
    91  var predeclOnce sync.Once
    92  var predecl []types.Type // initialized lazily
    93  
    94  func predeclared() []types.Type {
    95  	predeclOnce.Do(func() {
    96  		// initialize lazily to be sure that all
    97  		// elements have been initialized before
    98  		predecl = []types.Type{ // basic types
    99  			types.Typ[types.Bool],
   100  			types.Typ[types.Int],
   101  			types.Typ[types.Int8],
   102  			types.Typ[types.Int16],
   103  			types.Typ[types.Int32],
   104  			types.Typ[types.Int64],
   105  			types.Typ[types.Uint],
   106  			types.Typ[types.Uint8],
   107  			types.Typ[types.Uint16],
   108  			types.Typ[types.Uint32],
   109  			types.Typ[types.Uint64],
   110  			types.Typ[types.Uintptr],
   111  			types.Typ[types.Float32],
   112  			types.Typ[types.Float64],
   113  			types.Typ[types.Complex64],
   114  			types.Typ[types.Complex128],
   115  			types.Typ[types.String],
   116  
   117  			// basic type aliases
   118  			types.Universe.Lookup("byte").Type(),
   119  			types.Universe.Lookup("rune").Type(),
   120  
   121  			// error
   122  			types.Universe.Lookup("error").Type(),
   123  
   124  			// untyped types
   125  			types.Typ[types.UntypedBool],
   126  			types.Typ[types.UntypedInt],
   127  			types.Typ[types.UntypedRune],
   128  			types.Typ[types.UntypedFloat],
   129  			types.Typ[types.UntypedComplex],
   130  			types.Typ[types.UntypedString],
   131  			types.Typ[types.UntypedNil],
   132  
   133  			// package unsafe
   134  			types.Typ[types.UnsafePointer],
   135  
   136  			// invalid type
   137  			types.Typ[types.Invalid], // only appears in packages with errors
   138  
   139  			// used internally by gc; never used by this package or in .a files
   140  			anyType{},
   141  		}
   142  		predecl = append(predecl, additionalPredeclared()...)
   143  	})
   144  	return predecl
   145  }
   146  
   147  type anyType struct{}
   148  
   149  func (t anyType) Underlying() types.Type { return t }
   150  func (t anyType) String() string         { return "any" }
   151
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