--- /dev/null
+// Copyright 2013 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.
+
+package main
+
+import (
+ "bytes"
+ "flag"
+ "fmt"
+ "go/ast"
+ "go/parser"
+ "go/printer"
+ "go/token"
+ "io"
+ "io/ioutil"
+ "log"
+ "os"
+ "path/filepath"
+ "sort"
+ "strconv"
+ "strings"
+)
+
+const usageMessage = "" +
+ `Usage of 'go tool cover':
+Given a coverage profile produced by 'go test':
+ go test -coverprofile=c.out
+
+Open a web browser displaying annotated source code:
+ go tool cover -html=c.out
+
+Write out an HTML file instead of launching a web browser:
+ go tool cover -html=c.out -o coverage.html
+
+Display coverage percentages to stdout for each function:
+ go tool cover -func=c.out
+
+Finally, to generate modified source code with coverage annotations
+(what go test -cover does):
+ go tool cover -mode=set -var=CoverageVariableName program.go
+`
+
+func usage() {
+ fmt.Fprintln(os.Stderr, usageMessage)
+ fmt.Fprintln(os.Stderr, "Flags:")
+ flag.PrintDefaults()
+ fmt.Fprintln(os.Stderr, "\n Only one of -html, -func, or -mode may be set.")
+ os.Exit(2)
+}
+
+var (
+ mode = flag.String("mode", "", "coverage mode: set, count, atomic")
+ varVar = flag.String("var", "GoCover", "name of coverage variable to generate")
+ output = flag.String("o", "", "file for output; default: stdout")
+ htmlOut = flag.String("html", "", "generate HTML representation of coverage profile")
+ funcOut = flag.String("func", "", "output coverage profile information for each function")
+)
+
+var profile string // The profile to read; the value of -html or -func
+
+var counterStmt func(*File, ast.Expr) ast.Stmt
+
+const (
+ atomicPackagePath = "sync/atomic"
+ atomicPackageName = "_cover_atomic_"
+)
+
+func main() {
+ flag.Usage = usage
+ flag.Parse()
+
+ // Usage information when no arguments.
+ if flag.NFlag() == 0 && flag.NArg() == 0 {
+ flag.Usage()
+ }
+
+ err := parseFlags()
+ if err != nil {
+ fmt.Fprintln(os.Stderr, err)
+ fmt.Fprintln(os.Stderr, `For usage information, run "go tool cover -help"`)
+ os.Exit(2)
+ }
+
+ // Generate coverage-annotated source.
+ if *mode != "" {
+ annotate(flag.Arg(0))
+ return
+ }
+
+ // Output HTML or function coverage information.
+ if *htmlOut != "" {
+ err = htmlOutput(profile, *output)
+ } else {
+ err = funcOutput(profile, *output)
+ }
+
+ if err != nil {
+ fmt.Fprintf(os.Stderr, "cover: %v\n", err)
+ os.Exit(2)
+ }
+}
+
+// parseFlags sets the profile and counterStmt globals and performs validations.
+func parseFlags() error {
+ profile = *htmlOut
+ if *funcOut != "" {
+ if profile != "" {
+ return fmt.Errorf("too many options")
+ }
+ profile = *funcOut
+ }
+
+ // Must either display a profile or rewrite Go source.
+ if (profile == "") == (*mode == "") {
+ return fmt.Errorf("too many options")
+ }
+
+ if *mode != "" {
+ switch *mode {
+ case "set":
+ counterStmt = setCounterStmt
+ case "count":
+ counterStmt = incCounterStmt
+ case "atomic":
+ counterStmt = atomicCounterStmt
+ default:
+ return fmt.Errorf("unknown -mode %v", *mode)
+ }
+
+ if flag.NArg() == 0 {
+ return fmt.Errorf("missing source file")
+ } else if flag.NArg() == 1 {
+ return nil
+ }
+ } else if flag.NArg() == 0 {
+ return nil
+ }
+ return fmt.Errorf("too many arguments")
+}
+
+// Block represents the information about a basic block to be recorded in the analysis.
+// Note: Our definition of basic block is based on control structures; we don't break
+// apart && and ||. We could but it doesn't seem important enough to bother.
+type Block struct {
+ startByte token.Pos
+ endByte token.Pos
+ numStmt int
+}
+
+// File is a wrapper for the state of a file used in the parser.
+// The basic parse tree walker is a method of this type.
+type File struct {
+ fset *token.FileSet
+ name string // Name of file.
+ astFile *ast.File
+ blocks []Block
+ atomicPkg string // Package name for "sync/atomic" in this file.
+}
+
+// Visit implements the ast.Visitor interface.
+func (f *File) Visit(node ast.Node) ast.Visitor {
+ switch n := node.(type) {
+ case *ast.BlockStmt:
+ // If it's a switch or select, the body is a list of case clauses; don't tag the block itself.
+ if len(n.List) > 0 {
+ switch n.List[0].(type) {
+ case *ast.CaseClause: // switch
+ for _, n := range n.List {
+ clause := n.(*ast.CaseClause)
+ clause.Body = f.addCounters(clause.Pos(), clause.End(), clause.Body, false)
+ }
+ return f
+ case *ast.CommClause: // select
+ for _, n := range n.List {
+ clause := n.(*ast.CommClause)
+ clause.Body = f.addCounters(clause.Pos(), clause.End(), clause.Body, false)
+ }
+ return f
+ }
+ }
+ n.List = f.addCounters(n.Lbrace, n.Rbrace+1, n.List, true) // +1 to step past closing brace.
+ case *ast.IfStmt:
+ ast.Walk(f, n.Body)
+ if n.Else == nil {
+ return nil
+ }
+ // The elses are special, because if we have
+ // if x {
+ // } else if y {
+ // }
+ // we want to cover the "if y". To do this, we need a place to drop the counter,
+ // so we add a hidden block:
+ // if x {
+ // } else {
+ // if y {
+ // }
+ // }
+ switch stmt := n.Else.(type) {
+ case *ast.IfStmt:
+ block := &ast.BlockStmt{
+ Lbrace: n.Body.End(), // Start at end of the "if" block so the covered part looks like it starts at the "else".
+ List: []ast.Stmt{stmt},
+ Rbrace: stmt.End(),
+ }
+ n.Else = block
+ case *ast.BlockStmt:
+ stmt.Lbrace = n.Body.End() // Start at end of the "if" block so the covered part looks like it starts at the "else".
+ default:
+ panic("unexpected node type in if")
+ }
+ ast.Walk(f, n.Else)
+ return nil
+ case *ast.SelectStmt:
+ // Don't annotate an empty select - creates a syntax error.
+ if n.Body == nil || len(n.Body.List) == 0 {
+ return nil
+ }
+ case *ast.SwitchStmt:
+ // Don't annotate an empty switch - creates a syntax error.
+ if n.Body == nil || len(n.Body.List) == 0 {
+ return nil
+ }
+ case *ast.TypeSwitchStmt:
+ // Don't annotate an empty type switch - creates a syntax error.
+ if n.Body == nil || len(n.Body.List) == 0 {
+ return nil
+ }
+ }
+ return f
+}
+
+// unquote returns the unquoted string.
+func unquote(s string) string {
+ t, err := strconv.Unquote(s)
+ if err != nil {
+ log.Fatalf("cover: improperly quoted string %q\n", s)
+ }
+ return t
+}
+
+// addImport adds an import for the specified path, if one does not already exist, and returns
+// the local package name.
+func (f *File) addImport(path string) string {
+ // Does the package already import it?
+ for _, s := range f.astFile.Imports {
+ if unquote(s.Path.Value) == path {
+ if s.Name != nil {
+ return s.Name.Name
+ }
+ return filepath.Base(path)
+ }
+ }
+ newImport := &ast.ImportSpec{
+ Name: ast.NewIdent(atomicPackageName),
+ Path: &ast.BasicLit{
+ Kind: token.STRING,
+ Value: fmt.Sprintf("%q", path),
+ },
+ }
+ impDecl := &ast.GenDecl{
+ Tok: token.IMPORT,
+ Specs: []ast.Spec{
+ newImport,
+ },
+ }
+ // Make the new import the first Decl in the file.
+ astFile := f.astFile
+ astFile.Decls = append(astFile.Decls, nil)
+ copy(astFile.Decls[1:], astFile.Decls[0:])
+ astFile.Decls[0] = impDecl
+ astFile.Imports = append(astFile.Imports, newImport)
+
+ // Now refer to the package, just in case it ends up unused.
+ // That is, append to the end of the file the declaration
+ // var _ = _cover_atomic_.AddUint32
+ reference := &ast.GenDecl{
+ Tok: token.VAR,
+ Specs: []ast.Spec{
+ &ast.ValueSpec{
+ Names: []*ast.Ident{
+ ast.NewIdent("_"),
+ },
+ Values: []ast.Expr{
+ &ast.SelectorExpr{
+ X: ast.NewIdent(atomicPackageName),
+ Sel: ast.NewIdent("AddUint32"),
+ },
+ },
+ },
+ },
+ }
+ astFile.Decls = append(astFile.Decls, reference)
+ return atomicPackageName
+}
+
+var slashslash = []byte("//")
+
+// initialComments returns the prefix of content containing only
+// whitespace and line comments. Any +build directives must appear
+// within this region. This approach is more reliable than using
+// go/printer to print a modified AST containing comments.
+//
+func initialComments(content []byte) []byte {
+ // Derived from go/build.Context.shouldBuild.
+ end := 0
+ p := content
+ for len(p) > 0 {
+ line := p
+ if i := bytes.IndexByte(line, '\n'); i >= 0 {
+ line, p = line[:i], p[i+1:]
+ } else {
+ p = p[len(p):]
+ }
+ line = bytes.TrimSpace(line)
+ if len(line) == 0 { // Blank line.
+ end = len(content) - len(p)
+ continue
+ }
+ if !bytes.HasPrefix(line, slashslash) { // Not comment line.
+ break
+ }
+ }
+ return content[:end]
+}
+
+func annotate(name string) {
+ fset := token.NewFileSet()
+ content, err := ioutil.ReadFile(name)
+ if err != nil {
+ log.Fatalf("cover: %s: %s", name, err)
+ }
+ parsedFile, err := parser.ParseFile(fset, name, content, parser.ParseComments)
+ if err != nil {
+ log.Fatalf("cover: %s: %s", name, err)
+ }
+ parsedFile.Comments = trimComments(parsedFile, fset)
+
+ file := &File{
+ fset: fset,
+ name: name,
+ astFile: parsedFile,
+ }
+ if *mode == "atomic" {
+ file.atomicPkg = file.addImport(atomicPackagePath)
+ }
+ ast.Walk(file, file.astFile)
+ fd := os.Stdout
+ if *output != "" {
+ var err error
+ fd, err = os.Create(*output)
+ if err != nil {
+ log.Fatalf("cover: %s", err)
+ }
+ }
+ fd.Write(initialComments(content)) // Retain '// +build' directives.
+ file.print(fd)
+ // After printing the source tree, add some declarations for the counters etc.
+ // We could do this by adding to the tree, but it's easier just to print the text.
+ file.addVariables(fd)
+}
+
+// trimComments drops all but the //go: comments, some of which are semantically important.
+// We drop all others because they can appear in places that cause our counters
+// to appear in syntactically incorrect places. //go: appears at the beginning of
+// the line and is syntactically safe.
+func trimComments(file *ast.File, fset *token.FileSet) []*ast.CommentGroup {
+ var comments []*ast.CommentGroup
+ for _, group := range file.Comments {
+ var list []*ast.Comment
+ for _, comment := range group.List {
+ if strings.HasPrefix(comment.Text, "//go:") && fset.Position(comment.Slash).Column == 1 {
+ list = append(list, comment)
+ }
+ }
+ if list != nil {
+ comments = append(comments, &ast.CommentGroup{List: list})
+ }
+ }
+ return comments
+}
+
+func (f *File) print(w io.Writer) {
+ printer.Fprint(w, f.fset, f.astFile)
+}
+
+// intLiteral returns an ast.BasicLit representing the integer value.
+func (f *File) intLiteral(i int) *ast.BasicLit {
+ node := &ast.BasicLit{
+ Kind: token.INT,
+ Value: fmt.Sprint(i),
+ }
+ return node
+}
+
+// index returns an ast.BasicLit representing the number of counters present.
+func (f *File) index() *ast.BasicLit {
+ return f.intLiteral(len(f.blocks))
+}
+
+// setCounterStmt returns the expression: __count[23] = 1.
+func setCounterStmt(f *File, counter ast.Expr) ast.Stmt {
+ return &ast.AssignStmt{
+ Lhs: []ast.Expr{counter},
+ Tok: token.ASSIGN,
+ Rhs: []ast.Expr{f.intLiteral(1)},
+ }
+}
+
+// incCounterStmt returns the expression: __count[23]++.
+func incCounterStmt(f *File, counter ast.Expr) ast.Stmt {
+ return &ast.IncDecStmt{
+ X: counter,
+ Tok: token.INC,
+ }
+}
+
+// atomicCounterStmt returns the expression: atomic.AddUint32(&__count[23], 1)
+func atomicCounterStmt(f *File, counter ast.Expr) ast.Stmt {
+ return &ast.ExprStmt{
+ X: &ast.CallExpr{
+ Fun: &ast.SelectorExpr{
+ X: ast.NewIdent(f.atomicPkg),
+ Sel: ast.NewIdent("AddUint32"),
+ },
+ Args: []ast.Expr{&ast.UnaryExpr{
+ Op: token.AND,
+ X: counter,
+ },
+ f.intLiteral(1),
+ },
+ },
+ }
+}
+
+// newCounter creates a new counter expression of the appropriate form.
+func (f *File) newCounter(start, end token.Pos, numStmt int) ast.Stmt {
+ counter := &ast.IndexExpr{
+ X: &ast.SelectorExpr{
+ X: ast.NewIdent(*varVar),
+ Sel: ast.NewIdent("Count"),
+ },
+ Index: f.index(),
+ }
+ stmt := counterStmt(f, counter)
+ f.blocks = append(f.blocks, Block{start, end, numStmt})
+ return stmt
+}
+
+// addCounters takes a list of statements and adds counters to the beginning of
+// each basic block at the top level of that list. For instance, given
+//
+// S1
+// if cond {
+// S2
+// }
+// S3
+//
+// counters will be added before S1 and before S3. The block containing S2
+// will be visited in a separate call.
+// TODO: Nested simple blocks get unnecessary (but correct) counters
+func (f *File) addCounters(pos, blockEnd token.Pos, list []ast.Stmt, extendToClosingBrace bool) []ast.Stmt {
+ // Special case: make sure we add a counter to an empty block. Can't do this below
+ // or we will add a counter to an empty statement list after, say, a return statement.
+ if len(list) == 0 {
+ return []ast.Stmt{f.newCounter(pos, blockEnd, 0)}
+ }
+ // We have a block (statement list), but it may have several basic blocks due to the
+ // appearance of statements that affect the flow of control.
+ var newList []ast.Stmt
+ for {
+ // Find first statement that affects flow of control (break, continue, if, etc.).
+ // It will be the last statement of this basic block.
+ var last int
+ end := blockEnd
+ for last = 0; last < len(list); last++ {
+ end = f.statementBoundary(list[last])
+ if f.endsBasicSourceBlock(list[last]) {
+ extendToClosingBrace = false // Block is broken up now.
+ last++
+ break
+ }
+ }
+ if extendToClosingBrace {
+ end = blockEnd
+ }
+ if pos != end { // Can have no source to cover if e.g. blocks abut.
+ newList = append(newList, f.newCounter(pos, end, last))
+ }
+ newList = append(newList, list[0:last]...)
+ list = list[last:]
+ if len(list) == 0 {
+ break
+ }
+ pos = list[0].Pos()
+ }
+ return newList
+}
+
+// hasFuncLiteral reports the existence and position of the first func literal
+// in the node, if any. If a func literal appears, it usually marks the termination
+// of a basic block because the function body is itself a block.
+// Therefore we draw a line at the start of the body of the first function literal we find.
+// TODO: what if there's more than one? Probably doesn't matter much.
+func hasFuncLiteral(n ast.Node) (bool, token.Pos) {
+ if n == nil {
+ return false, 0
+ }
+ var literal funcLitFinder
+ ast.Walk(&literal, n)
+ return literal.found(), token.Pos(literal)
+}
+
+// statementBoundary finds the location in s that terminates the current basic
+// block in the source.
+func (f *File) statementBoundary(s ast.Stmt) token.Pos {
+ // Control flow statements are easy.
+ switch s := s.(type) {
+ case *ast.BlockStmt:
+ // Treat blocks like basic blocks to avoid overlapping counters.
+ return s.Lbrace
+ case *ast.IfStmt:
+ found, pos := hasFuncLiteral(s.Init)
+ if found {
+ return pos
+ }
+ found, pos = hasFuncLiteral(s.Cond)
+ if found {
+ return pos
+ }
+ return s.Body.Lbrace
+ case *ast.ForStmt:
+ found, pos := hasFuncLiteral(s.Init)
+ if found {
+ return pos
+ }
+ found, pos = hasFuncLiteral(s.Cond)
+ if found {
+ return pos
+ }
+ found, pos = hasFuncLiteral(s.Post)
+ if found {
+ return pos
+ }
+ return s.Body.Lbrace
+ case *ast.LabeledStmt:
+ return f.statementBoundary(s.Stmt)
+ case *ast.RangeStmt:
+ found, pos := hasFuncLiteral(s.X)
+ if found {
+ return pos
+ }
+ return s.Body.Lbrace
+ case *ast.SwitchStmt:
+ found, pos := hasFuncLiteral(s.Init)
+ if found {
+ return pos
+ }
+ found, pos = hasFuncLiteral(s.Tag)
+ if found {
+ return pos
+ }
+ return s.Body.Lbrace
+ case *ast.SelectStmt:
+ return s.Body.Lbrace
+ case *ast.TypeSwitchStmt:
+ found, pos := hasFuncLiteral(s.Init)
+ if found {
+ return pos
+ }
+ return s.Body.Lbrace
+ }
+ // If not a control flow statement, it is a declaration, expression, call, etc. and it may have a function literal.
+ // If it does, that's tricky because we want to exclude the body of the function from this block.
+ // Draw a line at the start of the body of the first function literal we find.
+ // TODO: what if there's more than one? Probably doesn't matter much.
+ found, pos := hasFuncLiteral(s)
+ if found {
+ return pos
+ }
+ return s.End()
+}
+
+// endsBasicSourceBlock reports whether s changes the flow of control: break, if, etc.,
+// or if it's just problematic, for instance contains a function literal, which will complicate
+// accounting due to the block-within-an expression.
+func (f *File) endsBasicSourceBlock(s ast.Stmt) bool {
+ switch s := s.(type) {
+ case *ast.BlockStmt:
+ // Treat blocks like basic blocks to avoid overlapping counters.
+ return true
+ case *ast.BranchStmt:
+ return true
+ case *ast.ForStmt:
+ return true
+ case *ast.IfStmt:
+ return true
+ case *ast.LabeledStmt:
+ return f.endsBasicSourceBlock(s.Stmt)
+ case *ast.RangeStmt:
+ return true
+ case *ast.SwitchStmt:
+ return true
+ case *ast.SelectStmt:
+ return true
+ case *ast.TypeSwitchStmt:
+ return true
+ case *ast.ExprStmt:
+ // Calls to panic change the flow.
+ // We really should verify that "panic" is the predefined function,
+ // but without type checking we can't and the likelihood of it being
+ // an actual problem is vanishingly small.
+ if call, ok := s.X.(*ast.CallExpr); ok {
+ if ident, ok := call.Fun.(*ast.Ident); ok && ident.Name == "panic" && len(call.Args) == 1 {
+ return true
+ }
+ }
+ }
+ found, _ := hasFuncLiteral(s)
+ return found
+}
+
+// funcLitFinder implements the ast.Visitor pattern to find the location of any
+// function literal in a subtree.
+type funcLitFinder token.Pos
+
+func (f *funcLitFinder) Visit(node ast.Node) (w ast.Visitor) {
+ if f.found() {
+ return nil // Prune search.
+ }
+ switch n := node.(type) {
+ case *ast.FuncLit:
+ *f = funcLitFinder(n.Body.Lbrace)
+ return nil // Prune search.
+ }
+ return f
+}
+
+func (f *funcLitFinder) found() bool {
+ return token.Pos(*f) != token.NoPos
+}
+
+// Sort interface for []block1; used for self-check in addVariables.
+
+type block1 struct {
+ Block
+ index int
+}
+
+type blockSlice []block1
+
+func (b blockSlice) Len() int { return len(b) }
+func (b blockSlice) Less(i, j int) bool { return b[i].startByte < b[j].startByte }
+func (b blockSlice) Swap(i, j int) { b[i], b[j] = b[j], b[i] }
+
+// offset translates a token position into a 0-indexed byte offset.
+func (f *File) offset(pos token.Pos) int {
+ return f.fset.Position(pos).Offset
+}
+
+// addVariables adds to the end of the file the declarations to set up the counter and position variables.
+func (f *File) addVariables(w io.Writer) {
+ // Self-check: Verify that the instrumented basic blocks are disjoint.
+ t := make([]block1, len(f.blocks))
+ for i := range f.blocks {
+ t[i].Block = f.blocks[i]
+ t[i].index = i
+ }
+ sort.Sort(blockSlice(t))
+ for i := 1; i < len(t); i++ {
+ if t[i-1].endByte > t[i].startByte {
+ fmt.Fprintf(os.Stderr, "cover: internal error: block %d overlaps block %d\n", t[i-1].index, t[i].index)
+ // Note: error message is in byte positions, not token positions.
+ fmt.Fprintf(os.Stderr, "\t%s:#%d,#%d %s:#%d,#%d\n",
+ f.name, f.offset(t[i-1].startByte), f.offset(t[i-1].endByte),
+ f.name, f.offset(t[i].startByte), f.offset(t[i].endByte))
+ }
+ }
+
+ // Declare the coverage struct as a package-level variable.
+ fmt.Fprintf(w, "\nvar %s = struct {\n", *varVar)
+ fmt.Fprintf(w, "\tCount [%d]uint32\n", len(f.blocks))
+ fmt.Fprintf(w, "\tPos [3 * %d]uint32\n", len(f.blocks))
+ fmt.Fprintf(w, "\tNumStmt [%d]uint16\n", len(f.blocks))
+ fmt.Fprintf(w, "} {\n")
+
+ // Initialize the position array field.
+ fmt.Fprintf(w, "\tPos: [3 * %d]uint32{\n", len(f.blocks))
+
+ // A nice long list of positions. Each position is encoded as follows to reduce size:
+ // - 32-bit starting line number
+ // - 32-bit ending line number
+ // - (16 bit ending column number << 16) | (16-bit starting column number).
+ for i, block := range f.blocks {
+ start := f.fset.Position(block.startByte)
+ end := f.fset.Position(block.endByte)
+ fmt.Fprintf(w, "\t\t%d, %d, %#x, // [%d]\n", start.Line, end.Line, (end.Column&0xFFFF)<<16|(start.Column&0xFFFF), i)
+ }
+
+ // Close the position array.
+ fmt.Fprintf(w, "\t},\n")
+
+ // Initialize the position array field.
+ fmt.Fprintf(w, "\tNumStmt: [%d]uint16{\n", len(f.blocks))
+
+ // A nice long list of statements-per-block, so we can give a conventional
+ // valuation of "percent covered". To save space, it's a 16-bit number, so we
+ // clamp it if it overflows - won't matter in practice.
+ for i, block := range f.blocks {
+ n := block.numStmt
+ if n > 1<<16-1 {
+ n = 1<<16 - 1
+ }
+ fmt.Fprintf(w, "\t\t%d, // %d\n", n, i)
+ }
+
+ // Close the statements-per-block array.
+ fmt.Fprintf(w, "\t},\n")
+
+ // Close the struct initialization.
+ fmt.Fprintf(w, "}\n")
+}
projects / dotfiles / .git / blobdiff