bimport.go

     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 ...any) {
    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  	_ = column // 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
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