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// Copyright 2021 The Tint 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.
// gen parses the <tint>/src/tint/intrinsics.def file, then scans the
// project directory for '<file>.tmpl' files, to produce source code files.
package main
import (
"flag"
"fmt"
"io"
"io/ioutil"
"math/rand"
"os"
"os/exec"
"path/filepath"
"reflect"
"regexp"
"runtime"
"strconv"
"strings"
"text/template"
"time"
"unicode"
"dawn.googlesource.com/dawn/tools/src/container"
"dawn.googlesource.com/dawn/tools/src/fileutils"
"dawn.googlesource.com/dawn/tools/src/glob"
"dawn.googlesource.com/dawn/tools/src/tint/intrinsic/gen"
"dawn.googlesource.com/dawn/tools/src/tint/intrinsic/parser"
"dawn.googlesource.com/dawn/tools/src/tint/intrinsic/resolver"
"dawn.googlesource.com/dawn/tools/src/tint/intrinsic/sem"
)
const defProjectRelPath = "src/tint/intrinsics.def"
func main() {
if err := run(); err != nil {
fmt.Println(err)
os.Exit(1)
}
}
func showUsage() {
fmt.Println(`
gen generates the templated code for the Tint compiler
gen scans the project directory for '<file>.tmpl' files, to produce source code
files.
If the templates use the 'IntrinsicTable' function then gen will parse and
resolve the <tint>/src/tint/intrinsics.def file.
usage:
gen
optional flags:`)
flag.PrintDefaults()
fmt.Println(``)
os.Exit(1)
}
func run() error {
projectRoot := fileutils.ProjectRoot()
// Find clang-format
clangFormatPath := findClangFormat(projectRoot)
if clangFormatPath == "" {
return fmt.Errorf("cannot find clang-format in <dawn>/buildtools nor PATH")
}
// Recursively find all the template files in the <tint>/src directory
files, err := glob.Scan(projectRoot, glob.MustParseConfig(`{
"paths": [{"include": [
"src/tint/**.tmpl",
"test/tint/**.tmpl"
]}]
}`))
if err != nil {
return err
}
cache := &genCache{}
// For each template file...
for _, relTmplPath := range files {
// Make tmplPath absolute
tmplPath := filepath.Join(projectRoot, relTmplPath)
// Read the template file
tmpl, err := ioutil.ReadFile(tmplPath)
if err != nil {
return fmt.Errorf("failed to open '%v': %w", tmplPath, err)
}
// Create or update the file at relpath if the file content has changed,
// preserving the copyright year in the header.
// relpath is a path relative to the template
writeFile := func(relpath, body string) error {
abspath := filepath.Join(filepath.Dir(tmplPath), relpath)
copyrightYear := time.Now().Year()
// Load the old file
existing, err := ioutil.ReadFile(abspath)
if err == nil {
// Look for the existing copyright year
if match := copyrightRegex.FindStringSubmatch(string(existing)); len(match) == 2 {
if year, err := strconv.Atoi(match[1]); err == nil {
copyrightYear = year
}
}
}
// Write the common file header
sb := strings.Builder{}
sb.WriteString(fmt.Sprintf(header, copyrightYear, filepath.ToSlash(relTmplPath)))
sb.WriteString(body)
content := sb.String()
return writeFileIfChanged(abspath, content, string(existing))
}
// Write the content generated using the template and semantic info
sb := strings.Builder{}
if err := generate(string(tmpl), cache, &sb, writeFile); err != nil {
return fmt.Errorf("while processing '%v': %w", tmplPath, err)
}
if body := sb.String(); body != "" {
_, tmplFileName := filepath.Split(tmplPath)
outFileName := strings.TrimSuffix(tmplFileName, ".tmpl")
switch filepath.Ext(outFileName) {
case ".cc", ".h", ".inl":
body, err = clangFormat(body, clangFormatPath)
if err != nil {
return err
}
}
if err := writeFile(outFileName, body); err != nil {
return err
}
}
}
return nil
}
// Cache for objects that are expensive to build, and can be reused between templates.
type genCache struct {
cached struct {
sem *sem.Sem // lazily built by sem()
intrinsicTable *gen.IntrinsicTable // lazily built by intrinsicTable()
permuter *gen.Permuter // lazily built by permute()
}
}
// sem lazily parses and resolves the intrinsic.def file, returning the semantic info.
func (g *genCache) sem() (*sem.Sem, error) {
if g.cached.sem == nil {
// Load the builtins definition file
defPath := filepath.Join(fileutils.ProjectRoot(), defProjectRelPath)
defSource, err := ioutil.ReadFile(defPath)
if err != nil {
return nil, err
}
// Parse the definition file to produce an AST
ast, err := parser.Parse(string(defSource), defProjectRelPath)
if err != nil {
return nil, err
}
// Resolve the AST to produce the semantic info
sem, err := resolver.Resolve(ast)
if err != nil {
return nil, err
}
g.cached.sem = sem
}
return g.cached.sem, nil
}
// intrinsicTable lazily calls and returns the result of buildIntrinsicTable(),
// caching the result for repeated calls.
func (g *genCache) intrinsicTable() (*gen.IntrinsicTable, error) {
if g.cached.intrinsicTable == nil {
sem, err := g.sem()
if err != nil {
return nil, err
}
g.cached.intrinsicTable, err = gen.BuildIntrinsicTable(sem)
if err != nil {
return nil, err
}
}
return g.cached.intrinsicTable, nil
}
// permute lazily calls buildPermuter(), caching the result for repeated
// calls, then passes the argument to Permutator.Permute()
func (g *genCache) permute(overload *sem.Overload) ([]gen.Permutation, error) {
if g.cached.permuter == nil {
sem, err := g.sem()
if err != nil {
return nil, err
}
g.cached.permuter, err = gen.NewPermuter(sem)
if err != nil {
return nil, err
}
}
return g.cached.permuter.Permute(overload)
}
// writes content to path if the file has changed
func writeFileIfChanged(path, newContent, oldContent string) error {
if oldContent == newContent {
return nil // Not changed
}
if err := os.MkdirAll(filepath.Dir(path), 0777); err != nil {
return fmt.Errorf("failed to create directory for '%v': %w", path, err)
}
if err := ioutil.WriteFile(path, []byte(newContent), 0666); err != nil {
return fmt.Errorf("failed to write file '%v': %w", path, err)
}
return nil
}
var copyrightRegex = regexp.MustCompile(`// Copyright (\d+) The`)
const header = `// Copyright %v The Tint 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.
////////////////////////////////////////////////////////////////////////////////
// File generated by tools/src/cmd/gen
// using the template:
// %v
//
// Do not modify this file directly
////////////////////////////////////////////////////////////////////////////////
`
type generator struct {
template *template.Template
cache *genCache
writeFile WriteFile
rnd *rand.Rand
}
// WriteFile is a function that Generate() may call to emit a new file from a
// template.
// relpath is the relative path from the currently executing template.
// content is the file content to write.
type WriteFile func(relpath, content string) error
// generate executes the template tmpl, writing the output to w.
// See https://golang.org/pkg/text/template/ for documentation on the template
// syntax.
func generate(tmpl string, cache *genCache, w io.Writer, writeFile WriteFile) error {
g := generator{
template: template.New("<template>"),
cache: cache,
writeFile: writeFile,
rnd: rand.New(rand.NewSource(4561123)),
}
if err := g.bindAndParse(g.template, tmpl); err != nil {
return err
}
return g.template.Execute(w, nil)
}
func (g *generator) bindAndParse(t *template.Template, text string) error {
_, err := t.Funcs(map[string]interface{}{
"Map": newMap,
"Iterate": iterate,
"Title": strings.Title,
"PascalCase": pascalCase,
"SplitDisplayName": gen.SplitDisplayName,
"HasPrefix": strings.HasPrefix,
"HasSuffix": strings.HasSuffix,
"TrimPrefix": strings.TrimPrefix,
"TrimSuffix": strings.TrimSuffix,
"TrimLeft": strings.TrimLeft,
"TrimRight": strings.TrimRight,
"Split": strings.Split,
"Scramble": g.scramble,
"IsEnumEntry": is(sem.EnumEntry{}),
"IsEnumMatcher": is(sem.EnumMatcher{}),
"IsFQN": is(sem.FullyQualifiedName{}),
"IsInt": is(1),
"IsTemplateEnumParam": is(sem.TemplateEnumParam{}),
"IsTemplateNumberParam": is(sem.TemplateNumberParam{}),
"IsTemplateTypeParam": is(sem.TemplateTypeParam{}),
"IsType": is(sem.Type{}),
"ElementType": gen.ElementType,
"DeepestElementType": gen.DeepestElementType,
"IsAbstract": gen.IsAbstract,
"IsDeclarable": gen.IsDeclarable,
"OverloadUsesF16": gen.OverloadUsesF16,
"IsFirstIn": isFirstIn,
"IsLastIn": isLastIn,
"Sem": g.cache.sem,
"IntrinsicTable": g.cache.intrinsicTable,
"Permute": g.cache.permute,
"Eval": g.eval,
"Import": g.importTmpl,
"WriteFile": func(relpath, content string) (string, error) { return "", g.writeFile(relpath, content) },
}).Option("missingkey=error").Parse(text)
return err
}
// eval executes the sub-template with the given name and argument, returning
// the generated output
func (g *generator) eval(template string, args ...interface{}) (string, error) {
target := g.template.Lookup(template)
if target == nil {
return "", fmt.Errorf("template '%v' not found", template)
}
sb := strings.Builder{}
var err error
if len(args) == 1 {
err = target.Execute(&sb, args[0])
} else {
m := newMap()
if len(args)%2 != 0 {
return "", fmt.Errorf("Eval expects a single argument or list name-value pairs")
}
for i := 0; i < len(args); i += 2 {
name, ok := args[i].(string)
if !ok {
return "", fmt.Errorf("Eval argument %v is not a string", i)
}
m.Put(name, args[i+1])
}
err = target.Execute(&sb, m)
}
if err != nil {
return "", fmt.Errorf("while evaluating '%v': %v", template, err)
}
return sb.String(), nil
}
// importTmpl parses the template at the given project-relative path, merging
// the template definitions into the global namespace.
// Note: The body of the template is not executed.
func (g *generator) importTmpl(path string) (string, error) {
if strings.Contains(path, "..") {
return "", fmt.Errorf("import path must not contain '..'")
}
path = filepath.Join(fileutils.ProjectRoot(), path)
data, err := ioutil.ReadFile(path)
if err != nil {
return "", fmt.Errorf("failed to open '%v': %w", path, err)
}
t := g.template.New("")
if err := g.bindAndParse(t, string(data)); err != nil {
return "", fmt.Errorf("failed to parse '%v': %w", path, err)
}
return "", nil
}
// scramble randomly modifies the input string so that it is no longer equal to
// any of the strings in 'avoid'.
func (g *generator) scramble(str string, avoid container.Set[string]) (string, error) {
bytes := []byte(str)
passes := g.rnd.Intn(5) + 1
const chars = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ_abcdefghijklmnopqrstuvwxyz"
char := func() byte { return chars[g.rnd.Intn(len(chars))] }
replace := func(at int) { bytes[at] = char() }
delete := func(at int) { bytes = append(bytes[:at], bytes[at+1:]...) }
insert := func(at int) { bytes = append(append(bytes[:at], char()), bytes[at:]...) }
for i := 0; i < passes || avoid.Contains(string(bytes)); i++ {
if len(bytes) > 0 {
at := g.rnd.Intn(len(bytes))
switch g.rnd.Intn(3) {
case 0:
replace(at)
case 1:
delete(at)
case 2:
insert(at)
}
} else {
insert(0)
}
}
return string(bytes), nil
}
// Map is a simple generic key-value map, which can be used in the template
type Map map[interface{}]interface{}
func newMap() Map { return Map{} }
// Put adds the key-value pair into the map.
// Put always returns an empty string so nothing is printed in the template.
func (m Map) Put(key, value interface{}) string {
m[key] = value
return ""
}
// Get looks up and returns the value with the given key. If the map does not
// contain the given key, then nil is returned.
func (m Map) Get(key interface{}) interface{} {
return m[key]
}
// is returns a function that returns true if the value passed to the function
// matches the type of 'ty'.
func is(ty interface{}) func(interface{}) bool {
rty := reflect.TypeOf(ty)
return func(v interface{}) bool {
ty := reflect.TypeOf(v)
return ty == rty || ty == reflect.PtrTo(rty)
}
}
// isFirstIn returns true if v is the first element of the given slice.
func isFirstIn(v, slice interface{}) bool {
s := reflect.ValueOf(slice)
count := s.Len()
if count == 0 {
return false
}
return s.Index(0).Interface() == v
}
// isFirstIn returns true if v is the last element of the given slice.
func isLastIn(v, slice interface{}) bool {
s := reflect.ValueOf(slice)
count := s.Len()
if count == 0 {
return false
}
return s.Index(count-1).Interface() == v
}
// iterate returns a slice of length 'n', with each element equal to its index.
// Useful for: {{- range Iterate $n -}}<this will be looped $n times>{{end}}
func iterate(n int) []int {
out := make([]int, n)
for i := range out {
out[i] = i
}
return out
}
// pascalCase returns the snake-case string s transformed into 'PascalCase',
// Rules:
// * The first letter of the string is capitalized
// * Characters following an underscore or number are capitalized
// * Underscores are removed from the returned string
// See: https://en.wikipedia.org/wiki/Camel_case
func pascalCase(s string) string {
b := strings.Builder{}
upper := true
for _, r := range s {
if r == '_' {
upper = true
continue
}
if upper {
b.WriteRune(unicode.ToUpper(r))
upper = false
} else {
b.WriteRune(r)
}
if unicode.IsNumber(r) {
upper = true
}
}
return b.String()
}
// Invokes the clang-format executable at 'exe' to format the file content 'in'.
// Returns the formatted file.
func clangFormat(in, exe string) (string, error) {
cmd := exec.Command(exe)
cmd.Stdin = strings.NewReader(in)
out, err := cmd.CombinedOutput()
if err != nil {
return "", fmt.Errorf("clang-format failed:\n%v\n%v", string(out), err)
}
return string(out), nil
}
// Looks for clang-format in the 'buildtools' directory, falling back to PATH
func findClangFormat(projectRoot string) string {
var path string
switch runtime.GOOS {
case "linux":
path = filepath.Join(projectRoot, "buildtools/linux64/clang-format")
case "darwin":
path = filepath.Join(projectRoot, "buildtools/mac/clang-format")
case "windows":
path = filepath.Join(projectRoot, "buildtools/win/clang-format.exe")
}
if fileutils.IsExe(path) {
return path
}
var err error
path, err = exec.LookPath("clang-format")
if err == nil {
return path
}
return ""
}