cmd/compile: update types2.Info.FileVersions API to match go/types

This CL changes the FileVersions map to map to version strings
rather than Version structs, for use with the new go/versions
package.

Adjust the cmd/dist bootstrap package list to include go/version.

Adjust the compiler's noder to work with the new API.

For #62605.
For #63974.

Change-Id: I191a7015ba3fb61c646e9f9d3c3dbafc9653ccb5
Reviewed-on: https://go-review.googlesource.com/c/go/+/541296
Reviewed-by: Robert Griesemer <[email protected]>
Auto-Submit: Robert Griesemer <[email protected]>
TryBot-Result: Gopher Robot <[email protected]>
Run-TryBot: Robert Griesemer <[email protected]>
Reviewed-by: Cherry Mui <[email protected]>

Author: griesemer

src/cmd/compile/internal/noder/irgen.go

@@ -61,7 +61,7 @@ func checkFiles(m posMap, noders []*noder) (*types2.Package, *types2.Info) {
 		Implicits:          make(map[syntax.Node]types2.Object),
 		Scopes:             make(map[syntax.Node]*types2.Scope),
 		Instances:          make(map[*syntax.Name]types2.Instance),
-		FileVersions:       make(map[*syntax.PosBase]types2.Version),
+		FileVersions:       make(map[*syntax.PosBase]string),
 		// expand as needed
 	}
 	conf.Error = func(err error) {
@@ -72,8 +72,7 @@ func checkFiles(m posMap, noders []*noder) (*types2.Package, *types2.Info) {
 			for !posBase.IsFileBase() { // line directive base
 				posBase = posBase.Pos().Base()
 			}
-			v := info.FileVersions[posBase]
-			fileVersion := fmt.Sprintf("go%d.%d", v.Major, v.Minor)
+			fileVersion := info.FileVersions[posBase]
 			file := posBaseMap[posBase]
 			if file.GoVersion == fileVersion {
 				// If we have a version error caused by //go:build, report it.

src/cmd/compile/internal/noder/writer.go

@@ -8,6 +8,7 @@ import (
 	"fmt"
 	"go/constant"
 	"go/token"
+	"go/version"
 	"internal/buildcfg"
 	"internal/pkgbits"
 	"os"
@@ -1479,8 +1480,8 @@ func (w *writer) forStmt(stmt *syntax.ForStmt) {
 
 func (w *writer) distinctVars(stmt *syntax.ForStmt) bool {
 	lv := base.Debug.LoopVar
-	v := w.p.info.FileVersions[stmt.Pos().Base()]
-	is122 := v.Major == 0 && v.Minor == 0 || v.Major == 1 && v.Minor >= 22
+	fileVersion := w.p.info.FileVersions[stmt.Pos().Base()]
+	is122 := fileVersion == "" || version.Compare(fileVersion, "go1.22") >= 0
 
 	// Turning off loopvar for 1.22 is only possible with loopvarhash=qn
 	//

src/cmd/compile/internal/types2/api.go

@@ -294,10 +294,12 @@ type Info struct {
 	// appear in this list.
 	InitOrder []*Initializer
 
-	// FileVersions maps a file's position base to the file's Go version.
-	// If the file doesn't specify a version and Config.GoVersion is not
-	// given, the reported version is the zero version (Major, Minor = 0, 0).
-	FileVersions map[*syntax.PosBase]Version
+	// FileVersions maps a file to its Go version string.
+	// If the file doesn't specify a version, the reported
+	// string is Config.GoVersion.
+	// Version strings begin with “go”, like “go1.21”, and
+	// are suitable for use with the [go/version] package.
+	FileVersions map[*syntax.PosBase]string
 }
 
 func (info *Info) recordTypes() bool {
@@ -431,12 +433,6 @@ func (init *Initializer) String() string {
 	return buf.String()
 }
 
-// A Version represents a released Go version.
-type Version struct {
-	Major int
-	Minor int
-}
-
 // Check type-checks a package and returns the resulting package object and
 // the first error if any. Additionally, if info != nil, Check populates each
 // of the non-nil maps in the Info struct.

src/cmd/compile/internal/types2/api_test.go

@@ -2769,14 +2769,14 @@ func TestFileVersions(t *testing.T) {
 	for _, test := range []struct {
 		moduleVersion string
 		fileVersion   string
-		want          Version
+		wantVersion   string
 	}{
-		{"", "", Version{0, 0}},              // no versions specified
-		{"go1.19", "", Version{1, 19}},       // module version specified
-		{"", "go1.20", Version{0, 0}},        // file upgrade ignored
-		{"go1.19", "go1.20", Version{1, 20}}, // file upgrade permitted
-		{"go1.20", "go1.19", Version{1, 20}}, // file downgrade not permitted
-		{"go1.21", "go1.19", Version{1, 19}}, // file downgrade permitted (module version is >= go1.21)
+		{"", "", ""},                   // no versions specified
+		{"go1.19", "", "go1.19"},       // module version specified
+		{"", "go1.20", ""},             // file upgrade ignored
+		{"go1.19", "go1.20", "go1.20"}, // file upgrade permitted
+		{"go1.20", "go1.19", "go1.20"}, // file downgrade not permitted
+		{"go1.21", "go1.19", "go1.19"}, // file downgrade permitted (module version is >= go1.21)
 	} {
 		var src string
 		if test.fileVersion != "" {
@@ -2785,15 +2785,15 @@ func TestFileVersions(t *testing.T) {
 		src += "package p"
 
 		conf := Config{GoVersion: test.moduleVersion}
-		versions := make(map[*syntax.PosBase]Version)
+		versions := make(map[*syntax.PosBase]string)
 		var info Info
 		info.FileVersions = versions
 		mustTypecheck(src, &conf, &info)
 
 		n := 0
 		for _, v := range info.FileVersions {
-			want := test.want
-			if v.Major != want.Major || v.Minor != want.Minor {
+			want := test.wantVersion
+			if v != want {
 				t.Errorf("%q: unexpected file version: got %v, want %v", src, v, want)
 			}
 			n++

src/cmd/compile/internal/types2/check.go

@@ -292,8 +292,8 @@ func (check *Checker) initFiles(files []*syntax.File) {
 	}
 
 	for _, file := range check.files {
-		fbase := base(file.Pos())                     // fbase may be nil for tests
-		check.recordFileVersion(fbase, check.version) // record package version (possibly zero version)
+		fbase := base(file.Pos())                            // fbase may be nil for tests
+		check.recordFileVersion(fbase, check.conf.GoVersion) // record package version (possibly zero version)
 		v, _ := parseGoVersion(file.GoVersion)
 		if v.major > 0 {
 			if v.equal(check.version) {
@@ -319,7 +319,7 @@ func (check *Checker) initFiles(files []*syntax.File) {
 				check.posVers = make(map[*syntax.PosBase]version)
 			}
 			check.posVers[fbase] = v
-			check.recordFileVersion(fbase, v) // overwrite package version
+			check.recordFileVersion(fbase, file.GoVersion) // overwrite package version
 		}
 	}
 }
@@ -684,8 +684,8 @@ func (check *Checker) recordScope(node syntax.Node, scope *Scope) {
 	}
 }
 
-func (check *Checker) recordFileVersion(fbase *syntax.PosBase, v version) {
+func (check *Checker) recordFileVersion(fbase *syntax.PosBase, version string) {
 	if m := check.FileVersions; m != nil {
-		m[fbase] = Version{v.major, v.minor}
+		m[fbase] = version
 	}
 }

src/cmd/dist/buildtool.go

@@ -31,6 +31,7 @@ import (
 // include all packages within subdirectories as well.
 // These will be imported during bootstrap as bootstrap/name, like bootstrap/math/big.
 var bootstrapDirs = []string{
+	"cmp",
 	"cmd/asm",
 	"cmd/asm/internal/...",
 	"cmd/cgo",
@@ -61,6 +62,7 @@ var bootstrapDirs = []string{
 	"debug/pe",
 	"go/build/constraint",
 	"go/constant",
+	"go/version",
 	"internal/abi",
 	"internal/coverage",
 	"cmd/internal/cov/covcmd",
@@ -70,6 +72,7 @@ var bootstrapDirs = []string{
 	"internal/godebugs",
 	"internal/goexperiment",
 	"internal/goroot",
+	"internal/gover",
 	"internal/goversion",
 	// internal/lazyregexp is provided by Go 1.17, which permits it to
 	// be imported by other packages in this list, but is not provided

src/go/types/check.go

@@ -296,7 +296,7 @@ func (check *Checker) initFiles(files []*ast.File) {
 
 	// collect file versions
 	for _, file := range check.files {
-		check.recordFileVersion(file, check.conf.GoVersion)
+		check.recordFileVersion(file, check.conf.GoVersion) // record package version (possibly zero version)
 		if v, _ := parseGoVersion(file.GoVersion); v.major > 0 {
 			if v.equal(check.version) {
 				continue