Adding upstream version 1.16.10.upstream/1.16.10upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 729 insertions, 0 deletions

diff --git a/src/cmd/cover/cover.go b/src/cmd/cover/cover.go
new file mode 100644
index 0000000..7ee0008
--- /dev/null
+++ b/src/cmd/cover/cover.go
@@ -0,0 +1,729 @@
+// 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/token"
+	"io"
+	"log"
+	"os"
+	"sort"
+
+	"cmd/internal/edit"
+	"cmd/internal/objabi"
+)
+
+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, string) string
+
+const (
+	atomicPackagePath = "sync/atomic"
+	atomicPackageName = "_cover_atomic_"
+)
+
+func main() {
+	objabi.AddVersionFlag()
+	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 *varVar != "" && !token.IsIdentifier(*varVar) {
+		return fmt.Errorf("-var: %q is not a valid identifier", *varVar)
+	}
+
+	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
+	content []byte
+	edit    *edit.Buffer
+}
+
+// findText finds text in the original source, starting at pos.
+// It correctly skips over comments and assumes it need not
+// handle quoted strings.
+// It returns a byte offset within f.src.
+func (f *File) findText(pos token.Pos, text string) int {
+	b := []byte(text)
+	start := f.offset(pos)
+	i := start
+	s := f.content
+	for i < len(s) {
+		if bytes.HasPrefix(s[i:], b) {
+			return i
+		}
+		if i+2 <= len(s) && s[i] == '/' && s[i+1] == '/' {
+			for i < len(s) && s[i] != '\n' {
+				i++
+			}
+			continue
+		}
+		if i+2 <= len(s) && s[i] == '/' && s[i+1] == '*' {
+			for i += 2; ; i++ {
+				if i+2 > len(s) {
+					return 0
+				}
+				if s[i] == '*' && s[i+1] == '/' {
+					i += 2
+					break
+				}
+			}
+			continue
+		}
+		i++
+	}
+	return -1
+}
+
+// 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)
+					f.addCounters(clause.Colon+1, clause.Colon+1, clause.End(), clause.Body, false)
+				}
+				return f
+			case *ast.CommClause: // select
+				for _, n := range n.List {
+					clause := n.(*ast.CommClause)
+					f.addCounters(clause.Colon+1, clause.Colon+1, clause.End(), clause.Body, false)
+				}
+				return f
+			}
+		}
+		f.addCounters(n.Lbrace, n.Lbrace+1, n.Rbrace+1, n.List, true) // +1 to step past closing brace.
+	case *ast.IfStmt:
+		if n.Init != nil {
+			ast.Walk(f, n.Init)
+		}
+		ast.Walk(f, n.Cond)
+		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 {
+		//		}
+		//	}
+		elseOffset := f.findText(n.Body.End(), "else")
+		if elseOffset < 0 {
+			panic("lost else")
+		}
+		f.edit.Insert(elseOffset+4, "{")
+		f.edit.Insert(f.offset(n.Else.End()), "}")
+
+		// We just created a block, now walk it.
+		// Adjust the position of the new block to start after
+		// the "else". That will cause it to follow the "{"
+		// we inserted above.
+		pos := f.fset.File(n.Body.End()).Pos(elseOffset + 4)
+		switch stmt := n.Else.(type) {
+		case *ast.IfStmt:
+			block := &ast.BlockStmt{
+				Lbrace: pos,
+				List:   []ast.Stmt{stmt},
+				Rbrace: stmt.End(),
+			}
+			n.Else = block
+		case *ast.BlockStmt:
+			stmt.Lbrace = pos
+		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 {
+			if n.Init != nil {
+				ast.Walk(f, n.Init)
+			}
+			if n.Tag != nil {
+				ast.Walk(f, n.Tag)
+			}
+			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 {
+			if n.Init != nil {
+				ast.Walk(f, n.Init)
+			}
+			ast.Walk(f, n.Assign)
+			return nil
+		}
+	case *ast.FuncDecl:
+		// Don't annotate functions with blank names - they cannot be executed.
+		if n.Name.Name == "_" {
+			return nil
+		}
+	}
+	return f
+}
+
+func annotate(name string) {
+	fset := token.NewFileSet()
+	content, err := os.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)
+	}
+
+	file := &File{
+		fset:    fset,
+		name:    name,
+		content: content,
+		edit:    edit.NewBuffer(content),
+		astFile: parsedFile,
+	}
+	if *mode == "atomic" {
+		// Add import of sync/atomic immediately after package clause.
+		// We do this even if there is an existing import, because the
+		// existing import may be shadowed at any given place we want
+		// to refer to it, and our name (_cover_atomic_) is less likely to
+		// be shadowed.
+		file.edit.Insert(file.offset(file.astFile.Name.End()),
+			fmt.Sprintf("; import %s %q", atomicPackageName, atomicPackagePath))
+	}
+
+	ast.Walk(file, file.astFile)
+	newContent := file.edit.Bytes()
+
+	fd := os.Stdout
+	if *output != "" {
+		var err error
+		fd, err = os.Create(*output)
+		if err != nil {
+			log.Fatalf("cover: %s", err)
+		}
+	}
+
+	fmt.Fprintf(fd, "//line %s:1\n", name)
+	fd.Write(newContent)
+
+	// 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)
+}
+
+// setCounterStmt returns the expression: __count[23] = 1.
+func setCounterStmt(f *File, counter string) string {
+	return fmt.Sprintf("%s = 1", counter)
+}
+
+// incCounterStmt returns the expression: __count[23]++.
+func incCounterStmt(f *File, counter string) string {
+	return fmt.Sprintf("%s++", counter)
+}
+
+// atomicCounterStmt returns the expression: atomic.AddUint32(&__count[23], 1)
+func atomicCounterStmt(f *File, counter string) string {
+	return fmt.Sprintf("%s.AddUint32(&%s, 1)", atomicPackageName, counter)
+}
+
+// newCounter creates a new counter expression of the appropriate form.
+func (f *File) newCounter(start, end token.Pos, numStmt int) string {
+	stmt := counterStmt(f, fmt.Sprintf("%s.Count[%d]", *varVar, len(f.blocks)))
+	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, insertPos, blockEnd token.Pos, list []ast.Stmt, extendToClosingBrace bool) {
+	// 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 {
+		f.edit.Insert(f.offset(insertPos), f.newCounter(insertPos, blockEnd, 0)+";")
+		return
+	}
+	// Make a copy of the list, as we may mutate it and should leave the
+	// existing list intact.
+	list = append([]ast.Stmt(nil), list...)
+	// 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.
+	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++ {
+			stmt := list[last]
+			end = f.statementBoundary(stmt)
+			if f.endsBasicSourceBlock(stmt) {
+				// If it is a labeled statement, we need to place a counter between
+				// the label and its statement because it may be the target of a goto
+				// and thus start a basic block. That is, given
+				//	foo: stmt
+				// we need to create
+				//	foo: ; stmt
+				// and mark the label as a block-terminating statement.
+				// The result will then be
+				//	foo: COUNTER[n]++; stmt
+				// However, we can't do this if the labeled statement is already
+				// a control statement, such as a labeled for.
+				if label, isLabel := stmt.(*ast.LabeledStmt); isLabel && !f.isControl(label.Stmt) {
+					newLabel := *label
+					newLabel.Stmt = &ast.EmptyStmt{
+						Semicolon: label.Stmt.Pos(),
+						Implicit:  true,
+					}
+					end = label.Pos() // Previous block ends before the label.
+					list[last] = &newLabel
+					// Open a gap and drop in the old statement, now without a label.
+					list = append(list, nil)
+					copy(list[last+1:], list[last:])
+					list[last+1] = label.Stmt
+				}
+				last++
+				extendToClosingBrace = false // Block is broken up now.
+				break
+			}
+		}
+		if extendToClosingBrace {
+			end = blockEnd
+		}
+		if pos != end { // Can have no source to cover if e.g. blocks abut.
+			f.edit.Insert(f.offset(insertPos), f.newCounter(pos, end, last)+";")
+		}
+		list = list[last:]
+		if len(list) == 0 {
+			break
+		}
+		pos = list[0].Pos()
+		insertPos = pos
+	}
+}
+
+// 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 true // A goto may branch here, starting a new basic block.
+	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
+}
+
+// isControl reports whether s is a control statement that, if labeled, cannot be
+// separated from its label.
+func (f *File) isControl(s ast.Stmt) bool {
+	switch s.(type) {
+	case *ast.ForStmt, *ast.RangeStmt, *ast.SwitchStmt, *ast.SelectStmt, *ast.TypeSwitchStmt:
+		return true
+	}
+	return false
+}
+
+// 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)
+
+		start, end = dedup(start, end)
+
+		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")
+
+	// Emit a reference to the atomic package to avoid
+	// import and not used error when there's no code in a file.
+	if *mode == "atomic" {
+		fmt.Fprintf(w, "var _ = %s.LoadUint32\n", atomicPackageName)
+	}
+}
+
+// It is possible for positions to repeat when there is a line
+// directive that does not specify column information and the input
+// has not been passed through gofmt.
+// See issues #27530 and #30746.
+// Tests are TestHtmlUnformatted and TestLineDup.
+// We use a map to avoid duplicates.
+
+// pos2 is a pair of token.Position values, used as a map key type.
+type pos2 struct {
+	p1, p2 token.Position
+}
+
+// seenPos2 tracks whether we have seen a token.Position pair.
+var seenPos2 = make(map[pos2]bool)
+
+// dedup takes a token.Position pair and returns a pair that does not
+// duplicate any existing pair. The returned pair will have the Offset
+// fields cleared.
+func dedup(p1, p2 token.Position) (r1, r2 token.Position) {
+	key := pos2{
+		p1: p1,
+		p2: p2,
+	}
+
+	// We want to ignore the Offset fields in the map,
+	// since cover uses only file/line/column.
+	key.p1.Offset = 0
+	key.p2.Offset = 0
+
+	for seenPos2[key] {
+		key.p2.Column++
+	}
+	seenPos2[key] = true
+
+	return key.p1, key.p2
+}