go/types, types2: add Environment to Config

Port to types2 and adjust compiler accordingly.

Change-Id: I2e72b151ef834977dca64cb2e62cedcac4e46062
Reviewed-on: https://go-review.googlesource.com/c/go/+/348578
Trust: Robert Griesemer <gri@golang.org>
Run-TryBot: Robert Griesemer <gri@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Reviewed-by: Robert Findley <rfindley@google.com>
TryBot-Result: Go Bot <gobot@golang.org>

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

@@ -43,12 +43,12 @@ var haveLegacyImports = false
 // for an imported package by overloading writeNewExportFunc, then
 // that payload will be mapped into memory and passed to
 // newReadImportFunc.
-var newReadImportFunc = func(data string, pkg1 *types.Pkg, check *types2.Checker, packages map[string]*types2.Package) (pkg2 *types2.Package, err error) {
+var newReadImportFunc = func(data string, pkg1 *types.Pkg, env *types2.Environment, packages map[string]*types2.Package) (pkg2 *types2.Package, err error) {
 	panic("unexpected new export data payload")
 }
 
 type gcimports struct {
-	check    *types2.Checker
+	env      *types2.Environment
 	packages map[string]*types2.Package
 }
 
@@ -61,7 +61,7 @@ func (m *gcimports) ImportFrom(path, srcDir string, mode types2.ImportMode) (*ty
 		panic("mode must be 0")
 	}
 
-	_, pkg, err := readImportFile(path, typecheck.Target, m.check, m.packages)
+	_, pkg, err := readImportFile(path, typecheck.Target, m.env, m.packages)
 	return pkg, err
 }
 
@@ -224,7 +224,7 @@ func parseImportPath(pathLit *syntax.BasicLit) (string, error) {
 // readImportFile reads the import file for the given package path and
 // returns its types.Pkg representation. If packages is non-nil, the
 // types2.Package representation is also returned.
-func readImportFile(path string, target *ir.Package, check *types2.Checker, packages map[string]*types2.Package) (pkg1 *types.Pkg, pkg2 *types2.Package, err error) {
+func readImportFile(path string, target *ir.Package, env *types2.Environment, packages map[string]*types2.Package) (pkg1 *types.Pkg, pkg2 *types2.Package, err error) {
 	path, err = resolveImportPath(path)
 	if err != nil {
 		return
@@ -279,7 +279,7 @@ func readImportFile(path string, target *ir.Package, check *types2.Checker, pack
 			return
 		}
 
-		pkg2, err = newReadImportFunc(data, pkg1, check, packages)
+		pkg2, err = newReadImportFunc(data, pkg1, env, packages)
 	} else {
 		// We only have old data. Oh well, fall back to the legacy importers.
 		haveLegacyImports = true

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

@@ -34,10 +34,13 @@ func checkFiles(noders []*noder) (posMap, *types2.Package, *types2.Info) {
 	}
 
 	// typechecking
+	env := types2.NewEnvironment()
 	importer := gcimports{
+		env:      env,
 		packages: map[string]*types2.Package{"unsafe": types2.Unsafe},
 	}
 	conf := types2.Config{
+		Environment:           env,
 		GoVersion:             base.Flag.Lang,
 		IgnoreLabels:          true, // parser already checked via syntax.CheckBranches mode
 		CompilerErrorMessages: true, // use error strings matching existing compiler errors
@@ -60,9 +63,7 @@ func checkFiles(noders []*noder) (posMap, *types2.Package, *types2.Info) {
 		// expand as needed
 	}
 
-	pkg := types2.NewPackage(base.Ctxt.Pkgpath, "")
-	importer.check = types2.NewChecker(&conf, pkg, info)
-	err := importer.check.Files(files)
+	pkg, err := conf.Check(base.Ctxt.Pkgpath, files, info)
 
 	base.ExitIfErrors()
 	if err != nil {

src/cmd/compile/internal/noder/reader2.go

@@ -18,7 +18,7 @@ import (
 type pkgReader2 struct {
 	pkgDecoder
 
-	check   *types2.Checker
+	env     *types2.Environment
 	imports map[string]*types2.Package
 
 	posBases []*syntax.PosBase
@@ -26,11 +26,11 @@ type pkgReader2 struct {
 	typs     []types2.Type
 }
 
-func readPackage2(check *types2.Checker, imports map[string]*types2.Package, input pkgDecoder) *types2.Package {
+func readPackage2(env *types2.Environment, imports map[string]*types2.Package, input pkgDecoder) *types2.Package {
 	pr := pkgReader2{
 		pkgDecoder: input,
 
-		check:   check,
+		env:     env,
 		imports: imports,
 
 		posBases: make([]*syntax.PosBase, input.numElems(relocPosBase)),
@@ -233,9 +233,7 @@ func (r *reader2) doTyp() (res types2.Type) {
 		obj, targs := r.obj()
 		name := obj.(*types2.TypeName)
 		if len(targs) != 0 {
-			// TODO(mdempsky) should use a single shared environment here
-			//                (before, this used a shared checker)
-			t, _ := types2.Instantiate(types2.NewEnvironment(), name.Type(), targs, false)
+			t, _ := types2.Instantiate(r.p.env, name.Type(), targs, false)
 			return t
 		}
 		return name.Type()

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

@@ -78,12 +78,12 @@ func unified(noders []*noder) {
 		base.Errorf("cannot use -G and -d=quirksmode together")
 	}
 
-	newReadImportFunc = func(data string, pkg1 *types.Pkg, check *types2.Checker, packages map[string]*types2.Package) (pkg2 *types2.Package, err error) {
+	newReadImportFunc = func(data string, pkg1 *types.Pkg, env *types2.Environment, packages map[string]*types2.Package) (pkg2 *types2.Package, err error) {
 		pr := newPkgDecoder(pkg1.Path, data)
 
 		// Read package descriptors for both types2 and compiler backend.
 		readPackage(newPkgReader(pr), pkg1)
-		pkg2 = readPackage2(check, packages, pr)
+		pkg2 = readPackage2(env, packages, pr)
 		return
 	}
 

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

@@ -108,6 +108,11 @@ type ImporterFrom interface {
 // A Config specifies the configuration for type checking.
 // The zero value for Config is a ready-to-use default configuration.
 type Config struct {
+	// Environment is the environment used for resolving global
+	// identifiers. If nil, the type checker will initialize this
+	// field with a newly created environment.
+	Environment *Environment
+
 	// GoVersion describes the accepted Go language version. The string
 	// must follow the format "go%d.%d" (e.g. "go1.12") or ist must be
 	// empty; an empty string indicates the latest language version.

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

@@ -86,7 +86,6 @@ type Checker struct {
 	nextID  uint64                 // unique Id for type parameters (first valid Id is 1)
 	objMap  map[Object]*declInfo   // maps package-level objects and (non-interface) methods to declaration info
 	impMap  map[importKey]*Package // maps (import path, source directory) to (complete or fake) package
-	env     *Environment           // for deduplicating identical instances
 
 	// pkgPathMap maps package names to the set of distinct import paths we've
 	// seen for that name, anywhere in the import graph. It is used for
@@ -171,6 +170,11 @@ func NewChecker(conf *Config, pkg *Package, info *Info) *Checker {
 		conf = new(Config)
 	}
 
+	// make sure we have an environment
+	if conf.Environment == nil {
+		conf.Environment = NewEnvironment()
+	}
+
 	// make sure we have an info struct
 	if info == nil {
 		info = new(Info)
@@ -188,7 +192,6 @@ func NewChecker(conf *Config, pkg *Package, info *Info) *Checker {
 		version: version,
 		objMap:  make(map[Object]*declInfo),
 		impMap:  make(map[importKey]*Package),
-		env:     NewEnvironment(),
 	}
 }
 

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

@@ -317,7 +317,7 @@ func (check *Checker) validType(typ Type, path []Object) typeInfo {
 		}
 
 	case *Named:
-		t.expand(check.env)
+		t.expand(check.conf.Environment)
 
 		// don't touch the type if it is from a different package or the Universe scope
 		// (doing so would lead to a race condition - was issue #35049)

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

@@ -71,7 +71,7 @@ func (check *Checker) instantiate(pos syntax.Pos, typ Type, targs []Type, posLis
 		}()
 	}
 
-	inst := check.instance(pos, typ, targs, check.env)
+	inst := check.instance(pos, typ, targs, check.conf.Environment)
 
 	assert(len(posList) <= len(targs))
 	check.later(func() {

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

@@ -254,7 +254,7 @@ func (n *Named) expand(env *Environment) *Named {
 			// in subst) feels overly complicated. Can we simplify?
 			if env == nil {
 				if n.check != nil {
-					env = n.check.env
+					env = n.check.conf.Environment
 				} else {
 					// If we're instantiating lazily, we might be outside the scope of a
 					// type-checking pass. In that case we won't have a pre-existing

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

@@ -59,7 +59,7 @@ func (check *Checker) subst(pos syntax.Pos, typ Type, smap substMap, env *Enviro
 	if check != nil {
 		subst.check = check
 		if env == nil {
-			env = check.env
+			env = check.conf.Environment
 		}
 	}
 	if env == nil {

src/go/types/api.go

@@ -115,6 +115,11 @@ type ImporterFrom interface {
 // A Config specifies the configuration for type checking.
 // The zero value for Config is a ready-to-use default configuration.
 type Config struct {
+	// Environment is the environment used for resolving global
+	// identifiers. If nil, the type checker will initialize this
+	// field with a newly created environment.
+	Environment *Environment
+
 	// GoVersion describes the accepted Go language version. The string
 	// must follow the format "go%d.%d" (e.g. "go1.12") or it must be
 	// empty; an empty string indicates the latest language version.

src/go/types/check.go

@@ -89,7 +89,6 @@ type Checker struct {
 	nextID  uint64                 // unique Id for type parameters (first valid Id is 1)
 	objMap  map[Object]*declInfo   // maps package-level objects and (non-interface) methods to declaration info
 	impMap  map[importKey]*Package // maps (import path, source directory) to (complete or fake) package
-	env     *Environment           // for deduplicating identical instances
 
 	// pkgPathMap maps package names to the set of distinct import paths we've
 	// seen for that name, anywhere in the import graph. It is used for
@@ -174,6 +173,11 @@ func NewChecker(conf *Config, fset *token.FileSet, pkg *Package, info *Info) *Ch
 		conf = new(Config)
 	}
 
+	// make sure we have an environment
+	if conf.Environment == nil {
+		conf.Environment = NewEnvironment()
+	}
+
 	// make sure we have an info struct
 	if info == nil {
 		info = new(Info)
@@ -192,7 +196,6 @@ func NewChecker(conf *Config, fset *token.FileSet, pkg *Package, info *Info) *Ch
 		version: version,
 		objMap:  make(map[Object]*declInfo),
 		impMap:  make(map[importKey]*Package),
-		env:     NewEnvironment(),
 	}
 }
 

src/go/types/decl.go

@@ -316,7 +316,7 @@ func (check *Checker) validType(typ Type, path []Object) typeInfo {
 		}
 
 	case *Named:
-		t.expand(check.env)
+		t.expand(check.conf.Environment)
 		// don't touch the type if it is from a different package or the Universe scope
 		// (doing so would lead to a race condition - was issue #35049)
 		if t.obj.pkg != check.pkg {

src/go/types/instantiate.go

@@ -71,7 +71,7 @@ func (check *Checker) instantiate(pos token.Pos, typ Type, targs []Type, posList
 		}()
 	}
 
-	inst := check.instance(pos, typ, targs, check.env)
+	inst := check.instance(pos, typ, targs, check.conf.Environment)
 
 	assert(len(posList) <= len(targs))
 	check.later(func() {

src/go/types/named.go

@@ -254,7 +254,7 @@ func (n *Named) expand(env *Environment) *Named {
 			// in subst) feels overly complicated. Can we simplify?
 			if env == nil {
 				if n.check != nil {
-					env = n.check.env
+					env = n.check.conf.Environment
 				} else {
 					// If we're instantiating lazily, we might be outside the scope of a
 					// type-checking pass. In that case we won't have a pre-existing

src/go/types/subst.go

@@ -62,7 +62,7 @@ func (check *Checker) subst(pos token.Pos, typ Type, smap substMap, env *Environ
 	if check != nil {
 		subst.check = check
 		if env == nil {
-			env = check.env
+			env = check.conf.Environment
 		}
 	}
 	if env == nil {