summaryrefslogtreecommitdiffstats
path: root/src/cmd/cgo/ast.go
diff options
context:
space:
mode:
Diffstat (limited to '')
-rw-r--r--src/cmd/cgo/ast.go539
1 files changed, 539 insertions, 0 deletions
diff --git a/src/cmd/cgo/ast.go b/src/cmd/cgo/ast.go
new file mode 100644
index 0000000..a073407
--- /dev/null
+++ b/src/cmd/cgo/ast.go
@@ -0,0 +1,539 @@
+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Parse input AST and prepare Prog structure.
+
+package main
+
+import (
+ "fmt"
+ "go/ast"
+ "go/parser"
+ "go/scanner"
+ "go/token"
+ "os"
+ "strings"
+)
+
+func parse(name string, src []byte, flags parser.Mode) *ast.File {
+ ast1, err := parser.ParseFile(fset, name, src, flags)
+ if err != nil {
+ if list, ok := err.(scanner.ErrorList); ok {
+ // If err is a scanner.ErrorList, its String will print just
+ // the first error and then (+n more errors).
+ // Instead, turn it into a new Error that will return
+ // details for all the errors.
+ for _, e := range list {
+ fmt.Fprintln(os.Stderr, e)
+ }
+ os.Exit(2)
+ }
+ fatalf("parsing %s: %s", name, err)
+ }
+ return ast1
+}
+
+func sourceLine(n ast.Node) int {
+ return fset.Position(n.Pos()).Line
+}
+
+// ParseGo populates f with information learned from the Go source code
+// which was read from the named file. It gathers the C preamble
+// attached to the import "C" comment, a list of references to C.xxx,
+// a list of exported functions, and the actual AST, to be rewritten and
+// printed.
+func (f *File) ParseGo(abspath string, src []byte) {
+ // Two different parses: once with comments, once without.
+ // The printer is not good enough at printing comments in the
+ // right place when we start editing the AST behind its back,
+ // so we use ast1 to look for the doc comments on import "C"
+ // and on exported functions, and we use ast2 for translating
+ // and reprinting.
+ // In cgo mode, we ignore ast2 and just apply edits directly
+ // the text behind ast1. In godefs mode we modify and print ast2.
+ ast1 := parse(abspath, src, parser.ParseComments)
+ ast2 := parse(abspath, src, 0)
+
+ f.Package = ast1.Name.Name
+ f.Name = make(map[string]*Name)
+ f.NamePos = make(map[*Name]token.Pos)
+
+ // In ast1, find the import "C" line and get any extra C preamble.
+ sawC := false
+ for _, decl := range ast1.Decls {
+ d, ok := decl.(*ast.GenDecl)
+ if !ok {
+ continue
+ }
+ for _, spec := range d.Specs {
+ s, ok := spec.(*ast.ImportSpec)
+ if !ok || s.Path.Value != `"C"` {
+ continue
+ }
+ sawC = true
+ if s.Name != nil {
+ error_(s.Path.Pos(), `cannot rename import "C"`)
+ }
+ cg := s.Doc
+ if cg == nil && len(d.Specs) == 1 {
+ cg = d.Doc
+ }
+ if cg != nil {
+ f.Preamble += fmt.Sprintf("#line %d %q\n", sourceLine(cg), abspath)
+ f.Preamble += commentText(cg) + "\n"
+ f.Preamble += "#line 1 \"cgo-generated-wrapper\"\n"
+ }
+ }
+ }
+ if !sawC {
+ error_(ast1.Package, `cannot find import "C"`)
+ }
+
+ // In ast2, strip the import "C" line.
+ if *godefs {
+ w := 0
+ for _, decl := range ast2.Decls {
+ d, ok := decl.(*ast.GenDecl)
+ if !ok {
+ ast2.Decls[w] = decl
+ w++
+ continue
+ }
+ ws := 0
+ for _, spec := range d.Specs {
+ s, ok := spec.(*ast.ImportSpec)
+ if !ok || s.Path.Value != `"C"` {
+ d.Specs[ws] = spec
+ ws++
+ }
+ }
+ if ws == 0 {
+ continue
+ }
+ d.Specs = d.Specs[0:ws]
+ ast2.Decls[w] = d
+ w++
+ }
+ ast2.Decls = ast2.Decls[0:w]
+ } else {
+ for _, decl := range ast2.Decls {
+ d, ok := decl.(*ast.GenDecl)
+ if !ok {
+ continue
+ }
+ for _, spec := range d.Specs {
+ if s, ok := spec.(*ast.ImportSpec); ok && s.Path.Value == `"C"` {
+ // Replace "C" with _ "unsafe", to keep program valid.
+ // (Deleting import statement or clause is not safe if it is followed
+ // in the source by an explicit semicolon.)
+ f.Edit.Replace(f.offset(s.Path.Pos()), f.offset(s.Path.End()), `_ "unsafe"`)
+ }
+ }
+ }
+ }
+
+ // Accumulate pointers to uses of C.x.
+ if f.Ref == nil {
+ f.Ref = make([]*Ref, 0, 8)
+ }
+ f.walk(ast2, ctxProg, (*File).validateIdents)
+ f.walk(ast2, ctxProg, (*File).saveExprs)
+
+ // Accumulate exported functions.
+ // The comments are only on ast1 but we need to
+ // save the function bodies from ast2.
+ // The first walk fills in ExpFunc, and the
+ // second walk changes the entries to
+ // refer to ast2 instead.
+ f.walk(ast1, ctxProg, (*File).saveExport)
+ f.walk(ast2, ctxProg, (*File).saveExport2)
+
+ f.Comments = ast1.Comments
+ f.AST = ast2
+}
+
+// Like ast.CommentGroup's Text method but preserves
+// leading blank lines, so that line numbers line up.
+func commentText(g *ast.CommentGroup) string {
+ var pieces []string
+ for _, com := range g.List {
+ c := com.Text
+ // Remove comment markers.
+ // The parser has given us exactly the comment text.
+ switch c[1] {
+ case '/':
+ //-style comment (no newline at the end)
+ c = c[2:] + "\n"
+ case '*':
+ /*-style comment */
+ c = c[2 : len(c)-2]
+ }
+ pieces = append(pieces, c)
+ }
+ return strings.Join(pieces, "")
+}
+
+func (f *File) validateIdents(x interface{}, context astContext) {
+ if x, ok := x.(*ast.Ident); ok {
+ if f.isMangledName(x.Name) {
+ error_(x.Pos(), "identifier %q may conflict with identifiers generated by cgo", x.Name)
+ }
+ }
+}
+
+// Save various references we are going to need later.
+func (f *File) saveExprs(x interface{}, context astContext) {
+ switch x := x.(type) {
+ case *ast.Expr:
+ switch (*x).(type) {
+ case *ast.SelectorExpr:
+ f.saveRef(x, context)
+ }
+ case *ast.CallExpr:
+ f.saveCall(x, context)
+ }
+}
+
+// Save references to C.xxx for later processing.
+func (f *File) saveRef(n *ast.Expr, context astContext) {
+ sel := (*n).(*ast.SelectorExpr)
+ // For now, assume that the only instance of capital C is when
+ // used as the imported package identifier.
+ // The parser should take care of scoping in the future, so
+ // that we will be able to distinguish a "top-level C" from a
+ // local C.
+ if l, ok := sel.X.(*ast.Ident); !ok || l.Name != "C" {
+ return
+ }
+ if context == ctxAssign2 {
+ context = ctxExpr
+ }
+ if context == ctxEmbedType {
+ error_(sel.Pos(), "cannot embed C type")
+ }
+ goname := sel.Sel.Name
+ if goname == "errno" {
+ error_(sel.Pos(), "cannot refer to errno directly; see documentation")
+ return
+ }
+ if goname == "_CMalloc" {
+ error_(sel.Pos(), "cannot refer to C._CMalloc; use C.malloc")
+ return
+ }
+ if goname == "malloc" {
+ goname = "_CMalloc"
+ }
+ name := f.Name[goname]
+ if name == nil {
+ name = &Name{
+ Go: goname,
+ }
+ f.Name[goname] = name
+ f.NamePos[name] = sel.Pos()
+ }
+ f.Ref = append(f.Ref, &Ref{
+ Name: name,
+ Expr: n,
+ Context: context,
+ })
+}
+
+// Save calls to C.xxx for later processing.
+func (f *File) saveCall(call *ast.CallExpr, context astContext) {
+ sel, ok := call.Fun.(*ast.SelectorExpr)
+ if !ok {
+ return
+ }
+ if l, ok := sel.X.(*ast.Ident); !ok || l.Name != "C" {
+ return
+ }
+ c := &Call{Call: call, Deferred: context == ctxDefer}
+ f.Calls = append(f.Calls, c)
+}
+
+// If a function should be exported add it to ExpFunc.
+func (f *File) saveExport(x interface{}, context astContext) {
+ n, ok := x.(*ast.FuncDecl)
+ if !ok {
+ return
+ }
+
+ if n.Doc == nil {
+ return
+ }
+ for _, c := range n.Doc.List {
+ if !strings.HasPrefix(c.Text, "//export ") {
+ continue
+ }
+
+ name := strings.TrimSpace(c.Text[9:])
+ if name == "" {
+ error_(c.Pos(), "export missing name")
+ }
+
+ if name != n.Name.Name {
+ error_(c.Pos(), "export comment has wrong name %q, want %q", name, n.Name.Name)
+ }
+
+ doc := ""
+ for _, c1 := range n.Doc.List {
+ if c1 != c {
+ doc += c1.Text + "\n"
+ }
+ }
+
+ f.ExpFunc = append(f.ExpFunc, &ExpFunc{
+ Func: n,
+ ExpName: name,
+ Doc: doc,
+ })
+ break
+ }
+}
+
+// Make f.ExpFunc[i] point at the Func from this AST instead of the other one.
+func (f *File) saveExport2(x interface{}, context astContext) {
+ n, ok := x.(*ast.FuncDecl)
+ if !ok {
+ return
+ }
+
+ for _, exp := range f.ExpFunc {
+ if exp.Func.Name.Name == n.Name.Name {
+ exp.Func = n
+ break
+ }
+ }
+}
+
+type astContext int
+
+const (
+ ctxProg astContext = iota
+ ctxEmbedType
+ ctxType
+ ctxStmt
+ ctxExpr
+ ctxField
+ ctxParam
+ ctxAssign2 // assignment of a single expression to two variables
+ ctxSwitch
+ ctxTypeSwitch
+ ctxFile
+ ctxDecl
+ ctxSpec
+ ctxDefer
+ ctxCall // any function call other than ctxCall2
+ ctxCall2 // function call whose result is assigned to two variables
+ ctxSelector
+)
+
+// walk walks the AST x, calling visit(f, x, context) for each node.
+func (f *File) walk(x interface{}, context astContext, visit func(*File, interface{}, astContext)) {
+ visit(f, x, context)
+ switch n := x.(type) {
+ case *ast.Expr:
+ f.walk(*n, context, visit)
+
+ // everything else just recurs
+ default:
+ error_(token.NoPos, "unexpected type %T in walk", x)
+ panic("unexpected type")
+
+ case nil:
+
+ // These are ordered and grouped to match ../../go/ast/ast.go
+ case *ast.Field:
+ if len(n.Names) == 0 && context == ctxField {
+ f.walk(&n.Type, ctxEmbedType, visit)
+ } else {
+ f.walk(&n.Type, ctxType, visit)
+ }
+ case *ast.FieldList:
+ for _, field := range n.List {
+ f.walk(field, context, visit)
+ }
+ case *ast.BadExpr:
+ case *ast.Ident:
+ case *ast.Ellipsis:
+ f.walk(&n.Elt, ctxType, visit)
+ case *ast.BasicLit:
+ case *ast.FuncLit:
+ f.walk(n.Type, ctxType, visit)
+ f.walk(n.Body, ctxStmt, visit)
+ case *ast.CompositeLit:
+ f.walk(&n.Type, ctxType, visit)
+ f.walk(n.Elts, ctxExpr, visit)
+ case *ast.ParenExpr:
+ f.walk(&n.X, context, visit)
+ case *ast.SelectorExpr:
+ f.walk(&n.X, ctxSelector, visit)
+ case *ast.IndexExpr:
+ f.walk(&n.X, ctxExpr, visit)
+ f.walk(&n.Index, ctxExpr, visit)
+ case *ast.SliceExpr:
+ f.walk(&n.X, ctxExpr, visit)
+ if n.Low != nil {
+ f.walk(&n.Low, ctxExpr, visit)
+ }
+ if n.High != nil {
+ f.walk(&n.High, ctxExpr, visit)
+ }
+ if n.Max != nil {
+ f.walk(&n.Max, ctxExpr, visit)
+ }
+ case *ast.TypeAssertExpr:
+ f.walk(&n.X, ctxExpr, visit)
+ f.walk(&n.Type, ctxType, visit)
+ case *ast.CallExpr:
+ if context == ctxAssign2 {
+ f.walk(&n.Fun, ctxCall2, visit)
+ } else {
+ f.walk(&n.Fun, ctxCall, visit)
+ }
+ f.walk(n.Args, ctxExpr, visit)
+ case *ast.StarExpr:
+ f.walk(&n.X, context, visit)
+ case *ast.UnaryExpr:
+ f.walk(&n.X, ctxExpr, visit)
+ case *ast.BinaryExpr:
+ f.walk(&n.X, ctxExpr, visit)
+ f.walk(&n.Y, ctxExpr, visit)
+ case *ast.KeyValueExpr:
+ f.walk(&n.Key, ctxExpr, visit)
+ f.walk(&n.Value, ctxExpr, visit)
+
+ case *ast.ArrayType:
+ f.walk(&n.Len, ctxExpr, visit)
+ f.walk(&n.Elt, ctxType, visit)
+ case *ast.StructType:
+ f.walk(n.Fields, ctxField, visit)
+ case *ast.FuncType:
+ f.walk(n.Params, ctxParam, visit)
+ if n.Results != nil {
+ f.walk(n.Results, ctxParam, visit)
+ }
+ case *ast.InterfaceType:
+ f.walk(n.Methods, ctxField, visit)
+ case *ast.MapType:
+ f.walk(&n.Key, ctxType, visit)
+ f.walk(&n.Value, ctxType, visit)
+ case *ast.ChanType:
+ f.walk(&n.Value, ctxType, visit)
+
+ case *ast.BadStmt:
+ case *ast.DeclStmt:
+ f.walk(n.Decl, ctxDecl, visit)
+ case *ast.EmptyStmt:
+ case *ast.LabeledStmt:
+ f.walk(n.Stmt, ctxStmt, visit)
+ case *ast.ExprStmt:
+ f.walk(&n.X, ctxExpr, visit)
+ case *ast.SendStmt:
+ f.walk(&n.Chan, ctxExpr, visit)
+ f.walk(&n.Value, ctxExpr, visit)
+ case *ast.IncDecStmt:
+ f.walk(&n.X, ctxExpr, visit)
+ case *ast.AssignStmt:
+ f.walk(n.Lhs, ctxExpr, visit)
+ if len(n.Lhs) == 2 && len(n.Rhs) == 1 {
+ f.walk(n.Rhs, ctxAssign2, visit)
+ } else {
+ f.walk(n.Rhs, ctxExpr, visit)
+ }
+ case *ast.GoStmt:
+ f.walk(n.Call, ctxExpr, visit)
+ case *ast.DeferStmt:
+ f.walk(n.Call, ctxDefer, visit)
+ case *ast.ReturnStmt:
+ f.walk(n.Results, ctxExpr, visit)
+ case *ast.BranchStmt:
+ case *ast.BlockStmt:
+ f.walk(n.List, context, visit)
+ case *ast.IfStmt:
+ f.walk(n.Init, ctxStmt, visit)
+ f.walk(&n.Cond, ctxExpr, visit)
+ f.walk(n.Body, ctxStmt, visit)
+ f.walk(n.Else, ctxStmt, visit)
+ case *ast.CaseClause:
+ if context == ctxTypeSwitch {
+ context = ctxType
+ } else {
+ context = ctxExpr
+ }
+ f.walk(n.List, context, visit)
+ f.walk(n.Body, ctxStmt, visit)
+ case *ast.SwitchStmt:
+ f.walk(n.Init, ctxStmt, visit)
+ f.walk(&n.Tag, ctxExpr, visit)
+ f.walk(n.Body, ctxSwitch, visit)
+ case *ast.TypeSwitchStmt:
+ f.walk(n.Init, ctxStmt, visit)
+ f.walk(n.Assign, ctxStmt, visit)
+ f.walk(n.Body, ctxTypeSwitch, visit)
+ case *ast.CommClause:
+ f.walk(n.Comm, ctxStmt, visit)
+ f.walk(n.Body, ctxStmt, visit)
+ case *ast.SelectStmt:
+ f.walk(n.Body, ctxStmt, visit)
+ case *ast.ForStmt:
+ f.walk(n.Init, ctxStmt, visit)
+ f.walk(&n.Cond, ctxExpr, visit)
+ f.walk(n.Post, ctxStmt, visit)
+ f.walk(n.Body, ctxStmt, visit)
+ case *ast.RangeStmt:
+ f.walk(&n.Key, ctxExpr, visit)
+ f.walk(&n.Value, ctxExpr, visit)
+ f.walk(&n.X, ctxExpr, visit)
+ f.walk(n.Body, ctxStmt, visit)
+
+ case *ast.ImportSpec:
+ case *ast.ValueSpec:
+ f.walk(&n.Type, ctxType, visit)
+ if len(n.Names) == 2 && len(n.Values) == 1 {
+ f.walk(&n.Values[0], ctxAssign2, visit)
+ } else {
+ f.walk(n.Values, ctxExpr, visit)
+ }
+ case *ast.TypeSpec:
+ f.walk(&n.Type, ctxType, visit)
+
+ case *ast.BadDecl:
+ case *ast.GenDecl:
+ f.walk(n.Specs, ctxSpec, visit)
+ case *ast.FuncDecl:
+ if n.Recv != nil {
+ f.walk(n.Recv, ctxParam, visit)
+ }
+ f.walk(n.Type, ctxType, visit)
+ if n.Body != nil {
+ f.walk(n.Body, ctxStmt, visit)
+ }
+
+ case *ast.File:
+ f.walk(n.Decls, ctxDecl, visit)
+
+ case *ast.Package:
+ for _, file := range n.Files {
+ f.walk(file, ctxFile, visit)
+ }
+
+ case []ast.Decl:
+ for _, d := range n {
+ f.walk(d, context, visit)
+ }
+ case []ast.Expr:
+ for i := range n {
+ f.walk(&n[i], context, visit)
+ }
+ case []ast.Stmt:
+ for _, s := range n {
+ f.walk(s, context, visit)
+ }
+ case []ast.Spec:
+ for _, s := range n {
+ f.walk(s, context, visit)
+ }
+ }
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-09-27 02:18:23 +0000