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Diffstat (limited to 'tools/go_marshal/gomarshal/generator.go')
-rw-r--r-- | tools/go_marshal/gomarshal/generator.go | 433 |
1 files changed, 0 insertions, 433 deletions
diff --git a/tools/go_marshal/gomarshal/generator.go b/tools/go_marshal/gomarshal/generator.go deleted file mode 100644 index 729489de5..000000000 --- a/tools/go_marshal/gomarshal/generator.go +++ /dev/null @@ -1,433 +0,0 @@ -// Copyright 2019 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. - -// Package gomarshal implements the go_marshal code generator. See README.md. -package gomarshal - -import ( - "bytes" - "fmt" - "go/ast" - "go/parser" - "go/token" - "os" - "sort" - "strings" - - "gvisor.dev/gvisor/tools/tags" -) - -const ( - marshalImport = "gvisor.dev/gvisor/tools/go_marshal/marshal" - safecopyImport = "gvisor.dev/gvisor/pkg/safecopy" - usermemImport = "gvisor.dev/gvisor/pkg/usermem" -) - -// List of identifiers we use in generated code that may conflict with a -// similarly-named source identifier. Abort gracefully when we see these to -// avoid potentially confusing compilation failures in generated code. -// -// This only applies to import aliases at the moment. All other identifiers -// are qualified by a receiver argument, since they're struct fields. -// -// All recievers are single letters, so we don't allow import aliases to be a -// single letter. -var badIdents = []string{ - "addr", "blk", "buf", "dst", "dsts", "err", "hdr", "idx", "inner", "len", - "ptr", "src", "srcs", "task", "val", - // All single-letter identifiers. -} - -// Constructed fromt badIdents in init(). -var badIdentsMap map[string]struct{} - -func init() { - badIdentsMap = make(map[string]struct{}) - for _, ident := range badIdents { - badIdentsMap[ident] = struct{}{} - } -} - -// Generator drives code generation for a single invocation of the go_marshal -// utility. -// -// The Generator holds arguments passed to the tool, and drives parsing, -// processing and code Generator for all types marked with +marshal declared in -// the input files. -// -// See Generator.run() as the entry point. -type Generator struct { - // Paths to input go source files. - inputs []string - // Output file to write generated go source. - output *os.File - // Output file to write generated tests. - outputTest *os.File - // Package name for the generated file. - pkg string - // Set of extra packages to import in the generated file. - imports *importTable -} - -// NewGenerator creates a new code Generator. -func NewGenerator(srcs []string, out, outTest, pkg string, imports []string) (*Generator, error) { - f, err := os.OpenFile(out, os.O_CREATE|os.O_WRONLY|os.O_TRUNC, 0644) - if err != nil { - return nil, fmt.Errorf("Couldn't open output file %q: %v", out, err) - } - fTest, err := os.OpenFile(outTest, os.O_CREATE|os.O_WRONLY|os.O_TRUNC, 0644) - if err != nil { - return nil, fmt.Errorf("Couldn't open test output file %q: %v", out, err) - } - g := Generator{ - inputs: srcs, - output: f, - outputTest: fTest, - pkg: pkg, - imports: newImportTable(), - } - for _, i := range imports { - // All imports on the extra imports list are unconditionally marked as - // used, so that they're always added to the generated code. - g.imports.add(i).markUsed() - } - - // The following imports may or may not be used by the generated code, - // depending on what's required for the target types. Don't mark these as - // used by default. - g.imports.add("io") - g.imports.add("reflect") - g.imports.add("runtime") - g.imports.add("unsafe") - g.imports.add(marshalImport) - g.imports.add(safecopyImport) - g.imports.add(usermemImport) - - return &g, nil -} - -// writeHeader writes the header for the generated source file. The header -// includes the package name, package level comments and import statements. -func (g *Generator) writeHeader() error { - var b sourceBuffer - b.emit("// Automatically generated marshal implementation. See tools/go_marshal.\n\n") - - // Emit build tags. - if t := tags.Aggregate(g.inputs); len(t) > 0 { - b.emit(strings.Join(t.Lines(), "\n")) - b.emit("\n\n") - } - - // Package header. - b.emit("package %s\n\n", g.pkg) - if err := b.write(g.output); err != nil { - return err - } - - return g.imports.write(g.output) -} - -// writeTypeChecks writes a statement to force the compiler to perform a type -// check for all Marshallable types referenced by the generated code. -func (g *Generator) writeTypeChecks(ms map[string]struct{}) error { - if len(ms) == 0 { - return nil - } - - msl := make([]string, 0, len(ms)) - for m, _ := range ms { - msl = append(msl, m) - } - sort.Strings(msl) - - var buf bytes.Buffer - fmt.Fprint(&buf, "// Marshallable types used by this file.\n") - - for _, m := range msl { - fmt.Fprintf(&buf, "var _ marshal.Marshallable = (*%s)(nil)\n", m) - } - fmt.Fprint(&buf, "\n") - - _, err := fmt.Fprint(g.output, buf.String()) - return err -} - -// parse processes all input files passed this generator and produces a set of -// parsed go ASTs. -func (g *Generator) parse() ([]*ast.File, []*token.FileSet, error) { - debugf("go_marshal invoked with %d input files:\n", len(g.inputs)) - for _, path := range g.inputs { - debugf(" %s\n", path) - } - - files := make([]*ast.File, 0, len(g.inputs)) - fsets := make([]*token.FileSet, 0, len(g.inputs)) - - for _, path := range g.inputs { - fset := token.NewFileSet() - f, err := parser.ParseFile(fset, path, nil, parser.ParseComments) - if err != nil { - // Not a valid input file? - return nil, nil, fmt.Errorf("Input %q can't be parsed: %v", path, err) - } - - if debugEnabled() { - debugf("AST for %q:\n", path) - ast.Print(fset, f) - } - - files = append(files, f) - fsets = append(fsets, fset) - } - - return files, fsets, nil -} - -// collectMarshallableTypes walks the parsed AST and collects a list of type -// declarations for which we need to generate the Marshallable interface. -func (g *Generator) collectMarshallableTypes(a *ast.File, f *token.FileSet) []*ast.TypeSpec { - var types []*ast.TypeSpec - for _, decl := range a.Decls { - gdecl, ok := decl.(*ast.GenDecl) - // Type declaration? - if !ok || gdecl.Tok != token.TYPE { - debugfAt(f.Position(decl.Pos()), "Skipping declaration since it's not a type declaration.\n") - continue - } - // Does it have a comment? - if gdecl.Doc == nil { - debugfAt(f.Position(gdecl.Pos()), "Skipping declaration since it doesn't have a comment.\n") - continue - } - // Does the comment contain a "+marshal" line? - marked := false - for _, c := range gdecl.Doc.List { - if c.Text == "// +marshal" { - marked = true - break - } - } - if !marked { - debugfAt(f.Position(gdecl.Pos()), "Skipping declaration since it doesn't have a comment containing +marshal line.\n") - continue - } - for _, spec := range gdecl.Specs { - // We already confirmed we're in a type declaration earlier, so this - // cast will succeed. - t := spec.(*ast.TypeSpec) - switch t.Type.(type) { - case *ast.StructType: - debugfAt(f.Position(t.Pos()), "Collected marshallable struct %s.\n", t.Name.Name) - types = append(types, t) - continue - case *ast.Ident: // Newtype on primitive. - debugfAt(f.Position(t.Pos()), "Collected marshallable newtype on primitive %s.\n", t.Name.Name) - types = append(types, t) - continue - case *ast.ArrayType: // Newtype on array. - debugfAt(f.Position(t.Pos()), "Collected marshallable newtype on array %s.\n", t.Name.Name) - types = append(types, t) - continue - } - // A user specifically requested marshalling on this type, but we - // don't support it. - abortAt(f.Position(t.Pos()), fmt.Sprintf("Marshalling codegen was requested on type '%s', but go-marshal doesn't support this kind of declaration.\n", t.Name)) - } - } - return types -} - -// collectImports collects all imports from all input source files. Some of -// these imports are copied to the generated output, if they're referenced by -// the generated code. -// -// collectImports de-duplicates imports while building the list, and ensures -// identifiers in the generated code don't conflict with any imported package -// names. -func (g *Generator) collectImports(a *ast.File, f *token.FileSet) map[string]importStmt { - is := make(map[string]importStmt) - for _, decl := range a.Decls { - gdecl, ok := decl.(*ast.GenDecl) - // Import statement? - if !ok || gdecl.Tok != token.IMPORT { - continue - } - for _, spec := range gdecl.Specs { - i := g.imports.addFromSpec(spec.(*ast.ImportSpec), f) - debugf("Collected import '%s' as '%s'\n", i.path, i.name) - - // Make sure we have an import that doesn't use any local names that - // would conflict with identifiers in the generated code. - if len(i.name) == 1 { - abortAt(f.Position(spec.Pos()), fmt.Sprintf("Import has a single character local name '%s'; this may conflict with code generated by go_marshal, use a multi-character import alias", i.name)) - } - if _, ok := badIdentsMap[i.name]; ok { - abortAt(f.Position(spec.Pos()), fmt.Sprintf("Import name '%s' is likely to conflict with code generated by go_marshal, use a different import alias", i.name)) - } - } - } - return is - -} - -func (g *Generator) generateOne(t *ast.TypeSpec, fset *token.FileSet) *interfaceGenerator { - i := newInterfaceGenerator(t, fset) - switch ty := t.Type.(type) { - case *ast.StructType: - i.validateStruct(t, ty) - i.emitMarshallableForStruct(ty) - case *ast.Ident: - i.validatePrimitiveNewtype(ty) - i.emitMarshallableForPrimitiveNewtype(ty) - case *ast.ArrayType: - i.validateArrayNewtype(t.Name, ty) - // After validate, we can safely call arrayLen. - i.emitMarshallableForArrayNewtype(t.Name, ty.Elt.(*ast.Ident), arrayLen(ty)) - default: - // This should've been filtered out by collectMarshallabeTypes. - panic(fmt.Sprintf("Unexpected type %+v", ty)) - } - return i -} - -// generateOneTestSuite generates a test suite for the automatically generated -// implementations type t. -func (g *Generator) generateOneTestSuite(t *ast.TypeSpec) *testGenerator { - i := newTestGenerator(t) - i.emitTests() - return i -} - -// Run is the entry point to code generation using g. -// -// Run parses all input source files specified in g and emits generated code. -func (g *Generator) Run() error { - // Parse our input source files into ASTs and token sets. - asts, fsets, err := g.parse() - if err != nil { - return err - } - - if len(asts) != len(fsets) { - panic("ASTs and FileSets don't match") - } - - // Map of imports in source files; key = local package name, value = import - // path. - is := make(map[string]importStmt) - for i, a := range asts { - // Collect all imports from the source files. We may need to copy some - // of these to the generated code if they're referenced. This has to be - // done before the loop below because we need to process all ASTs before - // we start requesting imports to be copied one by one as we encounter - // them in each generated source. - for name, i := range g.collectImports(a, fsets[i]) { - is[name] = i - } - } - - var impls []*interfaceGenerator - var ts []*testGenerator - // Set of Marshallable types referenced by generated code. - ms := make(map[string]struct{}) - for i, a := range asts { - // Collect type declarations marked for code generation and generate - // Marshallable interfaces. - for _, t := range g.collectMarshallableTypes(a, fsets[i]) { - impl := g.generateOne(t, fsets[i]) - // Collect Marshallable types referenced by the generated code. - for ref, _ := range impl.ms { - ms[ref] = struct{}{} - } - impls = append(impls, impl) - // Collect imports referenced by the generated code and add them to - // the list of imports we need to copy to the generated code. - for name, _ := range impl.is { - if !g.imports.markUsed(name) { - panic(fmt.Sprintf("Generated code for '%s' referenced a non-existent import with local name '%s'", impl.typeName(), name)) - } - } - ts = append(ts, g.generateOneTestSuite(t)) - } - } - - // Write output file header. These include things like package name and - // import statements. - if err := g.writeHeader(); err != nil { - return err - } - - // Write type checks for referenced marshallable types to output file. - if err := g.writeTypeChecks(ms); err != nil { - return err - } - - // Write generated interfaces to output file. - for _, i := range impls { - if err := i.write(g.output); err != nil { - return err - } - } - - // Write generated tests to test file. - return g.writeTests(ts) -} - -// writeTests outputs tests for the generated interface implementations to a go -// source file. -func (g *Generator) writeTests(ts []*testGenerator) error { - var b sourceBuffer - b.emit("package %s\n\n", g.pkg) - if err := b.write(g.outputTest); err != nil { - return err - } - - // Collect and write test import statements. - imports := newImportTable() - for _, t := range ts { - imports.merge(t.imports) - } - - if err := imports.write(g.outputTest); err != nil { - return err - } - - // Write test functions. - - // If we didn't generate any Marshallable implementations, we can't just - // emit an empty test file, since that causes the build to fail with "no - // tests/benchmarks/examples found". Unfortunately we can't signal bazel to - // omit the entire package since the outputs are already defined before - // go-marshal is called. If we'd otherwise emit an empty test suite, emit an - // empty example instead. - if len(ts) == 0 { - b.reset() - b.emit("func ExampleEmptyTestSuite() {\n") - b.inIndent(func() { - b.emit("// This example is intentionally empty to ensure this file contains at least\n") - b.emit("// one testable entity. go-marshal is forced to emit a test file if a package\n") - b.emit("// is marked marshallable, but emitting a test file with no entities results\n") - b.emit("// in a build failure.\n") - }) - b.emit("}\n") - return b.write(g.outputTest) - } - - for _, t := range ts { - if err := t.write(g.outputTest); err != nil { - return err - } - } - return nil -} |