Revert "go/types: add UsesCgo config to support _cgo_gotypes.go"

This reverts CL 33677.

Reason for revert: NetBSD is broken

Updates #38649

Change-Id: Id60e3c97d3cb4fb0053dea03b95dbbb0b850c883
Reviewed-on: https://go-review.googlesource.com/c/go/+/230038
Run-TryBot: Andrew Bonventre <[email protected]>
Reviewed-by: Robert Griesemer <[email protected]>
Reviewed-by: Matthew Dempsky <[email protected]>

src/go/internal/srcimporter/srcimporter.go

@@ -14,11 +14,8 @@ import (
 	"go/token"
 	"go/types"
 	"io"
-	"io/ioutil"
 	"os"
-	"os/exec"
 	"path/filepath"
-	"strings"
 	"sync"
 )
 
@@ -118,6 +115,7 @@ func (p *Importer) ImportFrom(path, srcDir string, mode types.ImportMode) (*type
 	var firstHardErr error
 	conf := types.Config{
 		IgnoreFuncBodies: true,
+		FakeImportC:      true,
 		// continue type-checking after the first error
 		Error: func(err error) {
 			if firstHardErr == nil && !err.(types.Error).Soft {
@@ -127,21 +125,6 @@ func (p *Importer) ImportFrom(path, srcDir string, mode types.ImportMode) (*type
 		Importer: p,
 		Sizes:    p.sizes,
 	}
-	if len(bp.CgoFiles) > 0 {
-		if p.ctxt.OpenFile != nil {
-			// cgo, gcc, pkg-config, etc. do not support
-			// build.Context's VFS.
-			conf.FakeImportC = true
-		} else {
-			conf.UsesCgo = true
-			file, err := p.cgo(bp)
-			if err != nil {
-				return nil, err
-			}
-			files = append(files, file)
-		}
-	}
-
 	pkg, err = conf.Check(bp.ImportPath, p.fset, files, nil)
 	if err != nil {
 		// If there was a hard error it is possibly unsafe
@@ -198,47 +181,6 @@ func (p *Importer) parseFiles(dir string, filenames []string) ([]*ast.File, erro
 	return files, nil
 }
 
-func (p *Importer) cgo(bp *build.Package) (*ast.File, error) {
-	tmpdir, err := ioutil.TempDir("", "srcimporter")
-	if err != nil {
-		return nil, err
-	}
-	defer os.RemoveAll(tmpdir)
-
-	args := []string{"go", "tool", "cgo", "-objdir", tmpdir}
-	if bp.Goroot {
-		switch bp.ImportPath {
-		case "runtime/cgo":
-			args = append(args, "-import_runtime_cgo=false", "-import_syscall=false")
-		case "runtime/race":
-			args = append(args, "-import_syscall=false")
-		}
-	}
-	args = append(args, "--")
-	args = append(args, strings.Fields(os.Getenv("CGO_CPPFLAGS"))...)
-	args = append(args, bp.CgoCPPFLAGS...)
-	if len(bp.CgoPkgConfig) > 0 {
-		cmd := exec.Command("pkg-config", append([]string{"--cflags"}, bp.CgoPkgConfig...)...)
-		out, err := cmd.CombinedOutput()
-		if err != nil {
-			return nil, err
-		}
-		args = append(args, strings.Fields(string(out))...)
-	}
-	args = append(args, "-I", tmpdir)
-	args = append(args, strings.Fields(os.Getenv("CGO_CFLAGS"))...)
-	args = append(args, bp.CgoCFLAGS...)
-	args = append(args, bp.CgoFiles...)
-
-	cmd := exec.Command(args[0], args[1:]...)
-	cmd.Dir = bp.Dir
-	if err := cmd.Run(); err != nil {
-		return nil, err
-	}
-
-	return parser.ParseFile(p.fset, filepath.Join(tmpdir, "_cgo_gotypes.go"), nil, 0)
-}
-
 // context-controlled file system operations
 
 func (p *Importer) absPath(path string) (string, error) {

src/go/internal/srcimporter/srcimporter_test.go

@@ -232,14 +232,3 @@ func TestIssue23092(t *testing.T) {
 func TestIssue24392(t *testing.T) {
 	testImportPath(t, "go/internal/srcimporter/testdata/issue24392")
 }
-
-func TestCgo(t *testing.T) {
-	testenv.MustHaveGoBuild(t)
-	testenv.MustHaveCGO(t)
-
-	importer := New(&build.Default, token.NewFileSet(), make(map[string]*types.Package))
-	_, err := importer.ImportFrom("./misc/cgo/test", runtime.GOROOT(), 0)
-	if err != nil {
-		t.Fatalf("Import failed: %v", err)
-	}
-}

src/go/types/api.go

@@ -105,15 +105,6 @@ type Config struct {
 	//          Do not use casually!
 	FakeImportC bool
 
-	// If UsesCgo is set, the type checker expects the
-	// _cgo_gotypes.go file generated by running cmd/cgo to be
-	// provided as a package source file. Qualified identifiers
-	// referring to package C will be resolved to cgo-provided
-	// declarations within _cgo_gotypes.go.
-	//
-	// It is an error to set both FakeImportC and UsesCgo.
-	UsesCgo bool
-
 	// If Error != nil, it is called with each error found
 	// during type checking; err has dynamic type Error.
 	// Secondary errors (for instance, to enumerate all types
@@ -290,7 +281,7 @@ func (tv TypeAndValue) IsBuiltin() bool {
 // nil Value.
 func (tv TypeAndValue) IsValue() bool {
 	switch tv.mode {
-	case constant_, variable, mapindex, value, commaok, commaerr:
+	case constant_, variable, mapindex, value, commaok:
 		return true
 	}
 	return false

src/go/types/assignments.go

@@ -22,7 +22,7 @@ func (check *Checker) assignment(x *operand, T Type, context string) {
 	switch x.mode {
 	case invalid:
 		return // error reported before
-	case constant_, variable, mapindex, value, commaok, commaerr:
+	case constant_, variable, mapindex, value, commaok:
 		// ok
 	default:
 		unreachable()

src/go/types/call.go

@@ -9,7 +9,6 @@ package types
 import (
 	"go/ast"
 	"go/token"
-	"strings"
 )
 
 func (check *Checker) call(x *operand, e *ast.CallExpr) exprKind {
@@ -55,8 +54,6 @@ func (check *Checker) call(x *operand, e *ast.CallExpr) exprKind {
 
 	default:
 		// function/method call
-		cgocall := x.mode == cgofunc
-
 		sig, _ := x.typ.Underlying().(*Signature)
 		if sig == nil {
 			check.invalidOp(x.pos(), "cannot call non-function %s", x)
@@ -77,11 +74,7 @@ func (check *Checker) call(x *operand, e *ast.CallExpr) exprKind {
 		case 0:
 			x.mode = novalue
 		case 1:
-			if cgocall {
-				x.mode = commaerr
-			} else {
-				x.mode = value
-			}
+			x.mode = value
 			x.typ = sig.results.vars[0].typ // unpack tuple
 		default:
 			x.mode = value
@@ -199,13 +192,10 @@ func unpack(get getter, n int, allowCommaOk bool) (getter, int, bool) {
 		}, t.Len(), false
 	}
 
-	if x0.mode == mapindex || x0.mode == commaok || x0.mode == commaerr {
+	if x0.mode == mapindex || x0.mode == commaok {
 		// comma-ok value
 		if allowCommaOk {
 			a := [2]Type{x0.typ, Typ[UntypedBool]}
-			if x0.mode == commaerr {
-				a[1] = universeError
-			}
 			return func(x *operand, i int) {
 				x.mode = value
 				x.expr = x0.expr
@@ -312,17 +302,6 @@ func (check *Checker) argument(sig *Signature, i int, x *operand, ellipsis token
 	check.assignment(x, typ, context)
 }
 
-var cgoPrefixes = [...]string{
-	"_Ciconst_",
-	"_Cfconst_",
-	"_Csconst_",
-	"_Ctype_",
-	"_Cvar_", // actually a pointer to the var
-	"_Cfpvar_fp_",
-	"_Cfunc_",
-	"_Cmacro_", // function to evaluate the expanded expression
-}
-
 func (check *Checker) selector(x *operand, e *ast.SelectorExpr) {
 	// these must be declared before the "goto Error" statements
 	var (
@@ -343,43 +322,16 @@ func (check *Checker) selector(x *operand, e *ast.SelectorExpr) {
 			check.recordUse(ident, pname)
 			pname.used = true
 			pkg := pname.imported
-
-			var exp Object
-			funcMode := value
-			if pkg.cgo {
-				// cgo special cases C.malloc: it's
-				// rewritten to _CMalloc and does not
-				// support two-result calls.
-				if sel == "malloc" {
-					sel = "_CMalloc"
-				} else {
-					funcMode = cgofunc
-				}
-				for _, prefix := range cgoPrefixes {
-					// cgo objects are part of the current package (in file
-					// _cgo_gotypes.go). Use regular lookup.
-					_, exp = check.scope.LookupParent(prefix+sel, check.pos)
-					if exp != nil {
-						break
-					}
-				}
-				if exp == nil {
-					check.errorf(e.Sel.Pos(), "%s not declared by package C", sel)
-					goto Error
-				}
-				check.objDecl(exp, nil)
-			} else {
-				exp = pkg.scope.Lookup(sel)
-				if exp == nil {
-					if !pkg.fake {
-						check.errorf(e.Sel.Pos(), "%s not declared by package %s", sel, pkg.name)
-					}
-					goto Error
-				}
-				if !exp.Exported() {
-					check.errorf(e.Sel.Pos(), "%s not exported by package %s", sel, pkg.name)
-					// ok to continue
+			exp := pkg.scope.Lookup(sel)
+			if exp == nil {
+				if !pkg.fake {
+					check.errorf(e.Sel.Pos(), "%s not declared by package %s", sel, pkg.name)
 				}
+				goto Error
+			}
+			if !exp.Exported() {
+				check.errorf(e.Sel.Pos(), "%s not exported by package %s", sel, pkg.name)
+				// ok to continue
 			}
 			check.recordUse(e.Sel, exp)
 
@@ -397,16 +349,9 @@ func (check *Checker) selector(x *operand, e *ast.SelectorExpr) {
 			case *Var:
 				x.mode = variable
 				x.typ = exp.typ
-				if pkg.cgo && strings.HasPrefix(exp.name, "_Cvar_") {
-					x.typ = x.typ.(*Pointer).base
-				}
 			case *Func:
-				x.mode = funcMode
+				x.mode = value
 				x.typ = exp.typ
-				if pkg.cgo && strings.HasPrefix(exp.name, "_Cmacro_") {
-					x.mode = value
-					x.typ = x.typ.(*Signature).results.vars[0].typ
-				}
 			case *Builtin:
 				x.mode = builtin
 				x.typ = exp.typ

src/go/types/check.go

@@ -7,7 +7,6 @@
 package types
 
 import (
-	"errors"
 	"go/ast"
 	"go/constant"
 	"go/token"
@@ -248,13 +247,7 @@ func (check *Checker) handleBailout(err *error) {
 // Files checks the provided files as part of the checker's package.
 func (check *Checker) Files(files []*ast.File) error { return check.checkFiles(files) }
 
-var errBadCgo = errors.New("cannot use FakeImportC and UsesCgo together")
-
 func (check *Checker) checkFiles(files []*ast.File) (err error) {
-	if check.conf.FakeImportC && check.conf.UsesCgo {
-		return errBadCgo
-	}
-
 	defer check.handleBailout(&err)
 
 	check.initFiles(files)
@@ -355,7 +348,7 @@ func (check *Checker) recordCommaOkTypes(x ast.Expr, a [2]Type) {
 	if a[0] == nil || a[1] == nil {
 		return
 	}
-	assert(isTyped(a[0]) && isTyped(a[1]) && (isBoolean(a[1]) || a[1] == universeError))
+	assert(isTyped(a[0]) && isTyped(a[1]) && isBoolean(a[1]))
 	if m := check.Types; m != nil {
 		for {
 			tv := m[x]

src/go/types/operand.go

@@ -27,8 +27,6 @@ const (
 	mapindex                     // operand is a map index expression (acts like a variable on lhs, commaok on rhs of an assignment)
 	value                        // operand is a computed value
 	commaok                      // like value, but operand may be used in a comma,ok expression
-	commaerr                     // like commaok, but second value is error, not boolean
-	cgofunc                      // operand is a cgo function
 )
 
 var operandModeString = [...]string{
@@ -41,8 +39,6 @@ var operandModeString = [...]string{
 	mapindex:  "map index expression",
 	value:     "value",
 	commaok:   "comma, ok expression",
-	commaerr:  "comma, error expression",
-	cgofunc:   "cgo function",
 }
 
 // An operand represents an intermediate value during type checking.
@@ -98,12 +94,6 @@ func (x *operand) pos() token.Pos {
 // commaok    <expr> (<untyped kind> <mode>                    )
 // commaok    <expr> (               <mode>       of type <typ>)
 //
-// commaerr   <expr> (<untyped kind> <mode>                    )
-// commaerr   <expr> (               <mode>       of type <typ>)
-//
-// cgofunc    <expr> (<untyped kind> <mode>                    )
-// cgofunc    <expr> (               <mode>       of type <typ>)
-//
 func operandString(x *operand, qf Qualifier) string {
 	var buf bytes.Buffer
 

src/go/types/package.go

@@ -17,7 +17,6 @@ type Package struct {
 	complete bool
 	imports  []*Package
 	fake     bool // scope lookup errors are silently dropped if package is fake (internal use only)
-	cgo      bool // uses of this package will be rewritten into uses of declarations from _cgo_gotypes.go
 }
 
 // NewPackage returns a new Package for the given package path and name.

src/go/types/resolver.go

@@ -141,10 +141,9 @@ func (check *Checker) importPackage(pos token.Pos, path, dir string) *Package {
 	}
 
 	// no package yet => import it
-	if path == "C" && (check.conf.FakeImportC || check.conf.UsesCgo) {
+	if path == "C" && check.conf.FakeImportC {
 		imp = NewPackage("C", "C")
-		imp.fake = true // package scope is not populated
-		imp.cgo = check.conf.UsesCgo
+		imp.fake = true
 	} else {
 		// ordinary import
 		var err error

src/go/types/universe.go

@@ -21,10 +21,9 @@ var Universe *Scope
 var Unsafe *Package
 
 var (
-	universeIota  *Const
-	universeByte  *Basic // uint8 alias, but has name "byte"
-	universeRune  *Basic // int32 alias, but has name "rune"
-	universeError *Named
+	universeIota *Const
+	universeByte *Basic // uint8 alias, but has name "byte"
+	universeRune *Basic // int32 alias, but has name "rune"
 )
 
 // Typ contains the predeclared *Basic types indexed by their
@@ -201,7 +200,6 @@ func init() {
 	universeIota = Universe.Lookup("iota").(*Const)
 	universeByte = Universe.Lookup("byte").(*TypeName).typ.(*Basic)
 	universeRune = Universe.Lookup("rune").(*TypeName).typ.(*Basic)
-	universeError = Universe.Lookup("error").(*TypeName).typ.(*Named)
 }
 
 // Objects with names containing blanks are internal and not entered into