go/tools/gopackagesdriver: pass Compiler and Arch in DriverResponse (#3657)

go/tools/gopackagesdriver: pass Compiler and Arch in DriverResponse

go/packages is being changed to expect Compiler and Arch in its
DriverResponse (see golang.org/cl/516917) because we can't expect the
type of the types.Sizes returned by types.Sizes to be types.StdSizes.
(The default it uses when Compiler and Arch aren't set is the set of
types for gc,amd64, so there's no change in behavior if those fields
aren't set, but we should set them.)

Author: matloob

go/tools/gopackagesdriver/json_packages_driver.go

@@ -16,7 +16,7 @@ package main
 
 import (
 	"fmt"
-	"go/types"
+	"runtime"
 )
 
 type JSONPackagesDriver struct {
@@ -52,7 +52,8 @@ func (b *JSONPackagesDriver) GetResponse(labels []string) *driverResponse {
 
 	return &driverResponse{
 		NotHandled: false,
-		Sizes:      types.SizesFor("gc", "amd64").(*types.StdSizes),
+		Compiler:   "gc",
+		Arch:       runtime.GOARCH,
 		Roots:      rootPkgs,
 		Packages:   packages,
 	}

go/tools/gopackagesdriver/main.go

@@ -18,8 +18,8 @@ import (
 	"context"
 	"encoding/json"
 	"fmt"
-	"go/types"
 	"os"
+	"runtime"
 	"strings"
 )
 
@@ -31,8 +31,10 @@ type driverResponse struct {
 	// lists of multiple drivers, go/packages will fall back to the next driver.
 	NotHandled bool
 
-	// Sizes, if not nil, is the types.Sizes to use when type checking.
-	Sizes *types.StdSizes
+	// Compiler and Arch are the arguments pass of types.SizesFor
+	// to get a types.Sizes to use when type checking.
+	Compiler string
+	Arch     string
 
 	// Roots is the set of package IDs that make up the root packages.
 	// We have to encode this separately because when we encode a single package
@@ -63,7 +65,8 @@ var (
 	additionalKinds       = strings.Fields(os.Getenv("GOPACKAGESDRIVER_BAZEL_KINDS"))
 	emptyResponse         = &driverResponse{
 		NotHandled: true,
-		Sizes:      types.SizesFor("gc", "amd64").(*types.StdSizes),
+		Compiler:   "gc",
+		Arch:       runtime.GOARCH,
 		Roots:      []string{},
 		Packages:   []*FlatPackage{},
 	}