go/ssa: remove loader utility functions

Removes the loader utility functions loadProgram and buildPackage.
Renames buildContent to buildPackages.

For golang/go#69556

Change-Id: I13b4f14d8d8aedaa3edbaa54d34a97cc2d56253f
Reviewed-on: https://go-review.googlesource.com/c/tools/+/614717
Reviewed-by: Alan Donovan <adonovan@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>

go/ssa/builder_generic_test.go

@@ -519,7 +519,7 @@ func TestGenericBodies(t *testing.T) {
 		pkgname := parsePackageClause(t, content)
 		t.Run(pkgname, func(t *testing.T) {
 			t.Parallel()
-			ssapkg, f := buildContent(t, content, ssa.SanityCheckFunctions)
+			ssapkg, f := buildPackage(t, content, ssa.SanityCheckFunctions)
 			fset := ssapkg.Prog.Fset
 
 			// Collect all notes in f, i.e. comments starting with "//@ types".

go/ssa/builder_test.go

@@ -350,7 +350,7 @@ func init():
 	}
 	for _, test := range tests {
 		// Create a single-file main package.
-		mainPkg, _ := buildContent(t, test.input, test.mode)
+		mainPkg, _ := buildPackage(t, test.input, test.mode)
 		name := mainPkg.Pkg.Name()
 		initFunc := mainPkg.Func("init")
 		if initFunc == nil {
@@ -406,7 +406,7 @@ var (
 	t interface{} = new(struct{*T})
 )
 `
-	pkg, _ := buildContent(t, input, ssa.BuilderMode(0))
+	pkg, _ := buildPackage(t, input, ssa.BuilderMode(0))
 
 	// Enumerate reachable synthetic functions
 	want := map[string]string{

go/ssa/instantiate_test.go

@@ -12,42 +12,10 @@ import (
 	"strings"
 	"testing"
 
-	"golang.org/x/tools/go/loader"
 	"golang.org/x/tools/go/ssa"
 	"golang.org/x/tools/go/ssa/ssautil"
 )
 
-// loadProgram creates loader.Program out of p.
-func loadProgram(p string) (*loader.Program, error) {
-	// Parse
-	var conf loader.Config
-	f, err := conf.ParseFile("<input>", p)
-	if err != nil {
-		return nil, fmt.Errorf("parse: %v", err)
-	}
-	conf.CreateFromFiles("p", f)
-
-	// Load
-	lprog, err := conf.Load()
-	if err != nil {
-		return nil, fmt.Errorf("Load: %v", err)
-	}
-	return lprog, nil
-}
-
-// buildPackage builds and returns ssa representation of package pkg of lprog.
-func buildPackage(lprog *loader.Program, pkg string, mode ssa.BuilderMode) *ssa.Package {
-	prog := ssa.NewProgram(lprog.Fset, mode)
-
-	for _, info := range lprog.AllPackages {
-		prog.CreatePackage(info.Pkg, info.Files, &info.Info, info.Importable)
-	}
-
-	p := prog.Package(lprog.Package(pkg).Pkg)
-	p.Build()
-	return p
-}
-
 // TestNeedsInstance ensures that new method instances can be created via MethodValue.
 func TestNeedsInstance(t *testing.T) {
 	const input = `
@@ -72,17 +40,11 @@ func LoadPointer(addr *unsafe.Pointer) (val unsafe.Pointer)
 	//      func  init        func()
 	//      var   init$guard  bool
 
-	lprog, err := loadProgram(input)
-	if err != nil {
-		t.Fatal(err)
-	}
-
 	for _, mode := range []ssa.BuilderMode{
 		ssa.SanityCheckFunctions,
 		ssa.SanityCheckFunctions | ssa.InstantiateGenerics,
 	} {
-		// Create and build SSA
-		p := buildPackage(lprog, "p", mode)
+		p, _ := buildPackage(t, input, mode)
 		prog := p.Prog
 
 		ptr := p.Type("Pointer").Type().(*types.Named)
@@ -185,12 +147,7 @@ func entry(i int, a A) int {
 	return Id[int](i)
 }
 `
-	lprog, err := loadProgram(input)
-	if err != nil {
-		t.Fatal(err)
-	}
-
-	p := buildPackage(lprog, "p", ssa.SanityCheckFunctions)
+	p, _ := buildPackage(t, input, ssa.SanityCheckFunctions)
 	all := ssautil.AllFunctions(p.Prog)
 
 	for _, ti := range []struct {
@@ -298,12 +255,7 @@ func Foo[T any, S any](t T, s S) {
 	Foo[T, S](t, s)
 }
 `
-	lprog, err := loadProgram(input)
-	if err != nil {
-		t.Fatal(err)
-	}
-
-	p := buildPackage(lprog, "p", ssa.SanityCheckFunctions)
+	p, _ := buildPackage(t, input, ssa.SanityCheckFunctions)
 
 	all := ssautil.AllFunctions(p.Prog)
 	for _, test := range []struct {

go/ssa/testutil_test.go

@@ -100,12 +100,12 @@ func loadPackages(t testing.TB, src fs.FS, patterns ...string) []*packages.Packa
 	return pkgs
 }
 
-// buildContent builds the content of a go file into:
+// buildPackage builds the content of a go file into:
 // * a module with the same name as the package at the current go version,
 // * loads the package (parses and types checks),
 // * builds the package and its dependencies, and
 // * returns the built package and the parsed file.
-func buildContent(t testing.TB, content string, mode ssa.BuilderMode) (*ssa.Package, *ast.File) {
+func buildPackage(t testing.TB, content string, mode ssa.BuilderMode) (*ssa.Package, *ast.File) {
 	name := parsePackageClause(t, content)
 
 	fs := overlayFS(map[string][]byte{