diff options
Diffstat (limited to 'tools/go_fieldenum/main.go')
| -rw-r--r-- | tools/go_fieldenum/main.go | 310 |
1 files changed, 0 insertions, 310 deletions
diff --git a/tools/go_fieldenum/main.go b/tools/go_fieldenum/main.go deleted file mode 100644 index 68dfdb3db..000000000 --- a/tools/go_fieldenum/main.go +++ /dev/null @@ -1,310 +0,0 @@ -// Copyright 2021 The gVisor Authors. -// -// Licensed under the Apache License, Version 2.0 (the "License"); -// you may not use this file except in compliance with the License. -// You may obtain a copy of the License at -// -// http://www.apache.org/licenses/LICENSE-2.0 -// -// Unless required by applicable law or agreed to in writing, software -// distributed under the License is distributed on an "AS IS" BASIS, -// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. -// See the License for the specific language governing permissions and -// limitations under the License. - -// Binary fieldenum emits field bitmasks for all structs in a package marked -// "+fieldenum". -package main - -import ( - "flag" - "fmt" - "go/ast" - "go/parser" - "go/token" - "log" - "os" - "strings" -) - -var ( - outputPkg = flag.String("pkg", "", "output package") - outputFilename = flag.String("out", "-", "output filename") -) - -func main() { - // Parse command line arguments. - flag.Parse() - if len(*outputPkg) == 0 { - log.Fatalf("-pkg must be provided") - } - if len(flag.Args()) == 0 { - log.Fatalf("Input files must be provided") - } - - // Parse input files. - inputFiles := make([]*ast.File, 0, len(flag.Args())) - fset := token.NewFileSet() - for _, filename := range flag.Args() { - f, err := parser.ParseFile(fset, filename, nil, parser.ParseComments) - if err != nil { - log.Fatalf("Failed to parse input file %q: %v", filename, err) - } - inputFiles = append(inputFiles, f) - } - - // Determine which types are marked "+fieldenum" and will consequently have - // code generated. - fieldEnumTypes := make(map[string]fieldEnumTypeInfo) - for _, f := range inputFiles { - for _, decl := range f.Decls { - d, ok := decl.(*ast.GenDecl) - if !ok || d.Tok != token.TYPE || d.Doc == nil || len(d.Specs) == 0 { - continue - } - for _, l := range d.Doc.List { - const fieldenumPrefixWithSpace = "// +fieldenum " - if l.Text == "// +fieldenum" || strings.HasPrefix(l.Text, fieldenumPrefixWithSpace) { - spec := d.Specs[0].(*ast.TypeSpec) - name := spec.Name.Name - prefix := name - if len(l.Text) > len(fieldenumPrefixWithSpace) { - prefix = strings.TrimSpace(l.Text[len(fieldenumPrefixWithSpace):]) - } - st, ok := spec.Type.(*ast.StructType) - if !ok { - log.Fatalf("Type %s is marked +fieldenum, but is not a struct", name) - } - fieldEnumTypes[name] = fieldEnumTypeInfo{ - prefix: prefix, - structType: st, - } - break - } - } - } - } - - // Collect information for each type for which code is being generated. - structInfos := make([]structInfo, 0, len(fieldEnumTypes)) - needSyncAtomic := false - for typeName, typeInfo := range fieldEnumTypes { - var si structInfo - si.name = typeName - si.prefix = typeInfo.prefix - for _, field := range typeInfo.structType.Fields.List { - name := structFieldName(field) - // If the field's type is a type that is also marked +fieldenum, - // include a FieldSet for that type in this one's. The field must - // be a struct by value, since if it's a pointer then that struct - // might also point to or include this one (which would make - // FieldSet inclusion circular). It must also be a type defined in - // this package, since otherwise we don't know whether it's marked - // +fieldenum. Thus, field.Type must be an identifier (rather than - // an ast.StarExpr or SelectorExpr). - if tident, ok := field.Type.(*ast.Ident); ok { - if fieldTypeInfo, ok := fieldEnumTypes[tident.Name]; ok { - fsf := fieldSetField{ - fieldName: name, - typePrefix: fieldTypeInfo.prefix, - } - si.reprByFieldSet = append(si.reprByFieldSet, fsf) - si.allFields = append(si.allFields, fsf) - continue - } - } - si.reprByBit = append(si.reprByBit, name) - si.allFields = append(si.allFields, fieldSetField{ - fieldName: name, - }) - // sync/atomic import will be needed for FieldSet.Load(). - needSyncAtomic = true - } - structInfos = append(structInfos, si) - } - - // Build the output file. - var b strings.Builder - fmt.Fprintf(&b, "// Generated by go_fieldenum.\n\n") - fmt.Fprintf(&b, "package %s\n\n", *outputPkg) - if needSyncAtomic { - fmt.Fprintf(&b, "import \"sync/atomic\"\n\n") - } - for _, si := range structInfos { - si.writeTo(&b) - } - - if *outputFilename == "-" { - // Write output to stdout. - fmt.Printf("%s", b.String()) - } else { - // Write output to file. - f, err := os.OpenFile(*outputFilename, os.O_WRONLY|os.O_CREATE|os.O_EXCL, 0644) - if err != nil { - log.Fatalf("Failed to open output file %q: %v", *outputFilename, err) - } - if _, err := f.WriteString(b.String()); err != nil { - log.Fatalf("Failed to write output file %q: %v", *outputFilename, err) - } - f.Close() - } -} - -type fieldEnumTypeInfo struct { - prefix string - structType *ast.StructType -} - -// structInfo contains information about the code generated for a given struct. -type structInfo struct { - // name is the name of the represented struct. - name string - - // prefix is the prefix X applied to the name of each generated type and - // constant, referred to as X in the comments below for convenience. - prefix string - - // reprByBit contains the names of fields in X that should be represented - // by a bit in the bit mask XFieldSet.fields, and by a bool in XFields. - reprByBit []string - - // reprByFieldSet contains fields in X whose type is a named struct (e.g. - // Y) that has a corresponding FieldSet type YFieldSet, and which should - // therefore be represented by including a value of type YFieldSet in - // XFieldSet, and a value of type YFields in XFields. - reprByFieldSet []fieldSetField - - // allFields contains all fields in X in order of declaration. Fields in - // reprByBit have fieldSetField.typePrefix == "". - allFields []fieldSetField -} - -type fieldSetField struct { - fieldName string - typePrefix string -} - -func structFieldName(f *ast.Field) string { - if len(f.Names) != 0 { - return f.Names[0].Name - } - // For embedded struct fields, the field name is the unqualified type name. - texpr := f.Type - for { - switch t := texpr.(type) { - case *ast.StarExpr: - texpr = t.X - case *ast.SelectorExpr: - texpr = t.Sel - case *ast.Ident: - return t.Name - default: - panic(fmt.Sprintf("unexpected %T", texpr)) - } - } -} - -// Workaround for Go defect (map membership test isn't usable in an -// expression). -func fetContains(xs map[string]*ast.StructType, x string) bool { - _, ok := xs[x] - return ok -} - -func (si *structInfo) writeTo(b *strings.Builder) { - fmt.Fprintf(b, "// A %sField represents a field in %s.\n", si.prefix, si.name) - fmt.Fprintf(b, "type %sField uint\n\n", si.prefix) - if len(si.reprByBit) != 0 { - fmt.Fprintf(b, "// %sFieldX represents %s field X.\n", si.prefix, si.name) - fmt.Fprintf(b, "const (\n") - fmt.Fprintf(b, "\t%sField%s %sField = iota\n", si.prefix, si.reprByBit[0], si.prefix) - for _, fieldName := range si.reprByBit[1:] { - fmt.Fprintf(b, "\t%sField%s\n", si.prefix, fieldName) - } - fmt.Fprintf(b, ")\n\n") - } - - fmt.Fprintf(b, "// %sFields represents a set of fields in %s in a literal-friendly form.\n", si.prefix, si.name) - fmt.Fprintf(b, "// The zero value of %sFields represents an empty set.\n", si.prefix) - fmt.Fprintf(b, "type %sFields struct {\n", si.prefix) - for _, fieldSetField := range si.allFields { - if fieldSetField.typePrefix == "" { - fmt.Fprintf(b, "\t%s bool\n", fieldSetField.fieldName) - } else { - fmt.Fprintf(b, "\t%s %sFields\n", fieldSetField.fieldName, fieldSetField.typePrefix) - } - } - fmt.Fprintf(b, "}\n\n") - - fmt.Fprintf(b, "// %sFieldSet represents a set of fields in %s in a compact form.\n", si.prefix, si.name) - fmt.Fprintf(b, "// The zero value of %sFieldSet represents an empty set.\n", si.prefix) - fmt.Fprintf(b, "type %sFieldSet struct {\n", si.prefix) - numBitmaskUint32s := (len(si.reprByBit) + 31) / 32 - for _, fieldSetField := range si.reprByFieldSet { - fmt.Fprintf(b, "\t%s %sFieldSet\n", fieldSetField.fieldName, fieldSetField.typePrefix) - } - if len(si.reprByBit) != 0 { - fmt.Fprintf(b, "\tfields [%d]uint32\n", numBitmaskUint32s) - } - fmt.Fprintf(b, "}\n\n") - - if len(si.reprByBit) != 0 { - fmt.Fprintf(b, "// Contains returns true if f is present in the %sFieldSet.\n", si.prefix) - fmt.Fprintf(b, "func (fs %sFieldSet) Contains(f %sField) bool {\n", si.prefix, si.prefix) - if numBitmaskUint32s == 1 { - fmt.Fprintf(b, "\treturn fs.fields[0] & (uint32(1) << uint(f)) != 0\n") - } else { - fmt.Fprintf(b, "\treturn fs.fields[f/32] & (uint32(1) << (f%%32)) != 0\n") - } - fmt.Fprintf(b, "}\n\n") - - fmt.Fprintf(b, "// Add adds f to the %sFieldSet.\n", si.prefix) - fmt.Fprintf(b, "func (fs *%sFieldSet) Add(f %sField) {\n", si.prefix, si.prefix) - if numBitmaskUint32s == 1 { - fmt.Fprintf(b, "\tfs.fields[0] |= uint32(1) << uint(f)\n") - } else { - fmt.Fprintf(b, "\tfs.fields[f/32] |= uint32(1) << (f%%32)\n") - } - fmt.Fprintf(b, "}\n\n") - - fmt.Fprintf(b, "// Remove removes f from the %sFieldSet.\n", si.prefix) - fmt.Fprintf(b, "func (fs *%sFieldSet) Remove(f %sField) {\n", si.prefix, si.prefix) - if numBitmaskUint32s == 1 { - fmt.Fprintf(b, "\tfs.fields[0] &^= uint32(1) << uint(f)\n") - } else { - fmt.Fprintf(b, "\tfs.fields[f/32] &^= uint32(1) << (f%%32)\n") - } - fmt.Fprintf(b, "}\n\n") - } - - fmt.Fprintf(b, "// Load returns a copy of the %sFieldSet.\n", si.prefix) - fmt.Fprintf(b, "// Load is safe to call concurrently with AddFieldsLoadable, but not Add or Remove.\n") - fmt.Fprintf(b, "func (fs *%sFieldSet) Load() (copied %sFieldSet) {\n", si.prefix, si.prefix) - for _, fieldSetField := range si.reprByFieldSet { - fmt.Fprintf(b, "\tcopied.%s = fs.%s.Load()\n", fieldSetField.fieldName, fieldSetField.fieldName) - } - for i := 0; i < numBitmaskUint32s; i++ { - fmt.Fprintf(b, "\tcopied.fields[%d] = atomic.LoadUint32(&fs.fields[%d])\n", i, i) - } - fmt.Fprintf(b, "\treturn\n") - fmt.Fprintf(b, "}\n\n") - - fmt.Fprintf(b, "// AddFieldsLoadable adds the given fields to the %sFieldSet.\n", si.prefix) - fmt.Fprintf(b, "// AddFieldsLoadable is safe to call concurrently with Load, but not other methods (including other calls to AddFieldsLoadable).\n") - fmt.Fprintf(b, "func (fs *%sFieldSet) AddFieldsLoadable(fields %sFields) {\n", si.prefix, si.prefix) - for _, fieldSetField := range si.reprByFieldSet { - fmt.Fprintf(b, "\tfs.%s.AddFieldsLoadable(fields.%s)\n", fieldSetField.fieldName, fieldSetField.fieldName) - } - for _, fieldName := range si.reprByBit { - fieldConstName := fmt.Sprintf("%sField%s", si.prefix, fieldName) - fmt.Fprintf(b, "\tif fields.%s {\n", fieldName) - if numBitmaskUint32s == 1 { - fmt.Fprintf(b, "\t\tatomic.StoreUint32(&fs.fields[0], fs.fields[0] | (uint32(1) << uint(%s)))\n", fieldConstName) - } else { - fmt.Fprintf(b, "\t\tword, bit := %s/32, %s%%32\n", fieldConstName, fieldConstName) - fmt.Fprintf(b, "\t\tatomic.StoreUint32(&fs.fields[word], fs.fields[word] | (uint32(1) << bit))\n") - } - fmt.Fprintf(b, "\t}\n") - } - fmt.Fprintf(b, "}\n\n") -} |