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// Copyright 2013 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
//lint:file-ignore SA1019 go/ssa's test suite is built around the deprecated go/loader. We'll leave fixing that to upstream.
package ssa_test
import (
"bytes"
"go/ast"
"go/importer"
"go/parser"
"go/token"
"go/types"
"os"
"reflect"
"sort"
"strings"
"testing"
"golang.org/x/tools/go/loader"
"honnef.co/go/tools/ssa"
"honnef.co/go/tools/ssa/ssautil"
)
func isEmpty(f *ssa.Function) bool { return f.Blocks == nil }
// Tests that programs partially loaded from gc object files contain
// functions with no code for the external portions, but are otherwise ok.
func TestBuildPackage(t *testing.T) {
input := `
package main
import (
"bytes"
"io"
"testing"
)
func main() {
var t testing.T
t.Parallel() // static call to external declared method
t.Fail() // static call to promoted external declared method
testing.Short() // static call to external package-level function
var w io.Writer = new(bytes.Buffer)
w.Write(nil) // interface invoke of external declared method
}
`
// Parse the file.
fset := token.NewFileSet()
f, err := parser.ParseFile(fset, "input.go", input, 0)
if err != nil {
t.Error(err)
return
}
// Build an SSA program from the parsed file.
// Load its dependencies from gc binary export data.
mainPkg, _, err := ssautil.BuildPackage(&types.Config{Importer: importer.Default()}, fset,
types.NewPackage("main", ""), []*ast.File{f}, ssa.SanityCheckFunctions)
if err != nil {
t.Error(err)
return
}
// The main package, its direct and indirect dependencies are loaded.
deps := []string{
// directly imported dependencies:
"bytes", "io", "testing",
// indirect dependencies mentioned by
// the direct imports' export data
"sync", "unicode", "time",
}
prog := mainPkg.Prog
all := prog.AllPackages()
if len(all) <= len(deps) {
t.Errorf("unexpected set of loaded packages: %q", all)
}
for _, path := range deps {
pkg := prog.ImportedPackage(path)
if pkg == nil {
t.Errorf("package not loaded: %q", path)
continue
}
// External packages should have no function bodies (except for wrappers).
isExt := pkg != mainPkg
// init()
if isExt && !isEmpty(pkg.Func("init")) {
t.Errorf("external package %s has non-empty init", pkg)
} else if !isExt && isEmpty(pkg.Func("init")) {
t.Errorf("main package %s has empty init", pkg)
}
for _, mem := range pkg.Members {
switch mem := mem.(type) {
case *ssa.Function:
// Functions at package level.
if isExt && !isEmpty(mem) {
t.Errorf("external function %s is non-empty", mem)
} else if !isExt && isEmpty(mem) {
t.Errorf("function %s is empty", mem)
}
case *ssa.Type:
// Methods of named types T.
// (In this test, all exported methods belong to *T not T.)
if !isExt {
t.Fatalf("unexpected name type in main package: %s", mem)
}
mset := prog.MethodSets.MethodSet(types.NewPointer(mem.Type()))
for i, n := 0, mset.Len(); i < n; i++ {
m := prog.MethodValue(mset.At(i))
// For external types, only synthetic wrappers have code.
expExt := !strings.Contains(m.Synthetic, "wrapper")
if expExt && !isEmpty(m) {
t.Errorf("external method %s is non-empty: %s",
m, m.Synthetic)
} else if !expExt && isEmpty(m) {
t.Errorf("method function %s is empty: %s",
m, m.Synthetic)
}
}
}
}
}
expectedCallee := []string{
"(*testing.T).Parallel",
"(*testing.common).Fail",
"testing.Short",
"N/A",
}
callNum := 0
for _, b := range mainPkg.Func("main").Blocks {
for _, instr := range b.Instrs {
switch instr := instr.(type) {
case ssa.CallInstruction:
call := instr.Common()
if want := expectedCallee[callNum]; want != "N/A" {
got := call.StaticCallee().String()
if want != got {
t.Errorf("call #%d from main.main: got callee %s, want %s",
callNum, got, want)
}
}
callNum++
}
}
}
if callNum != 4 {
t.Errorf("in main.main: got %d calls, want %d", callNum, 4)
}
}
// TestRuntimeTypes tests that (*Program).RuntimeTypes() includes all necessary types.
func TestRuntimeTypes(t *testing.T) {
tests := []struct {
input string
want []string
}{
// An exported package-level type is needed.
{`package A; type T struct{}; func (T) f() {}`,
[]string{"*p.T", "p.T"},
},
// An unexported package-level type is not needed.
{`package B; type t struct{}; func (t) f() {}`,
nil,
},
// Subcomponents of type of exported package-level var are needed.
{`package C; import "bytes"; var V struct {*bytes.Buffer}`,
[]string{"*bytes.Buffer", "*struct{*bytes.Buffer}", "struct{*bytes.Buffer}"},
},
// Subcomponents of type of unexported package-level var are not needed.
{`package D; import "bytes"; var v struct {*bytes.Buffer}`,
nil,
},
// Subcomponents of type of exported package-level function are needed.
{`package E; import "bytes"; func F(struct {*bytes.Buffer}) {}`,
[]string{"*bytes.Buffer", "struct{*bytes.Buffer}"},
},
// Subcomponents of type of unexported package-level function are not needed.
{`package F; import "bytes"; func f(struct {*bytes.Buffer}) {}`,
nil,
},
// Subcomponents of type of exported method of uninstantiated unexported type are not needed.
{`package G; import "bytes"; type x struct{}; func (x) G(struct {*bytes.Buffer}) {}; var v x`,
nil,
},
// ...unless used by MakeInterface.
{`package G2; import "bytes"; type x struct{}; func (x) G(struct {*bytes.Buffer}) {}; var v interface{} = x{}`,
[]string{"*bytes.Buffer", "*p.x", "p.x", "struct{*bytes.Buffer}"},
},
// Subcomponents of type of unexported method are not needed.
{`package I; import "bytes"; type X struct{}; func (X) G(struct {*bytes.Buffer}) {}`,
[]string{"*bytes.Buffer", "*p.X", "p.X", "struct{*bytes.Buffer}"},
},
// Local types aren't needed.
{`package J; import "bytes"; func f() { type T struct {*bytes.Buffer}; var t T; _ = t }`,
nil,
},
// ...unless used by MakeInterface.
{`package K; import "bytes"; func f() { type T struct {*bytes.Buffer}; _ = interface{}(T{}) }`,
[]string{"*bytes.Buffer", "*p.T", "p.T"},
},
// Types used as operand of MakeInterface are needed.
{`package L; import "bytes"; func f() { _ = interface{}(struct{*bytes.Buffer}{}) }`,
[]string{"*bytes.Buffer", "struct{*bytes.Buffer}"},
},
// MakeInterface is optimized away when storing to a blank.
{`package M; import "bytes"; var _ interface{} = struct{*bytes.Buffer}{}`,
nil,
},
}
for _, test := range tests {
// Parse the file.
fset := token.NewFileSet()
f, err := parser.ParseFile(fset, "input.go", test.input, 0)
if err != nil {
t.Errorf("test %q: %s", test.input[:15], err)
continue
}
// Create a single-file main package.
// Load dependencies from gc binary export data.
ssapkg, _, err := ssautil.BuildPackage(&types.Config{Importer: importer.Default()}, fset,
types.NewPackage("p", ""), []*ast.File{f}, ssa.SanityCheckFunctions)
if err != nil {
t.Errorf("test %q: %s", test.input[:15], err)
continue
}
var typstrs []string
for _, T := range ssapkg.Prog.RuntimeTypes() {
typstrs = append(typstrs, T.String())
}
sort.Strings(typstrs)
if !reflect.DeepEqual(typstrs, test.want) {
t.Errorf("test 'package %s': got %q, want %q",
f.Name.Name, typstrs, test.want)
}
}
}
// TestInit tests that synthesized init functions are correctly formed.
// Bare init functions omit calls to dependent init functions and the use of
// an init guard. They are useful in cases where the client uses a different
// calling convention for init functions, or cases where it is easier for a
// client to analyze bare init functions. Both of these aspects are used by
// the llgo compiler for simpler integration with gccgo's runtime library,
// and to simplify the analysis whereby it deduces which stores to globals
// can be lowered to global initializers.
func TestInit(t *testing.T) {
tests := []struct {
mode ssa.BuilderMode
input, want string
}{
{0, `package A; import _ "errors"; var i int = 42`,
`# Name: A.init
# Package: A
# Synthetic: package initializer
func init():
0: entry P:0 S:2
t0 = *init$guard bool
if t0 goto 2 else 1
1: init.start P:1 S:1
*init$guard = true:bool
t1 = errors.init() ()
*i = 42:int
jump 2
2: init.done P:2 S:0
return
`},
{ssa.BareInits, `package B; import _ "errors"; var i int = 42`,
`# Name: B.init
# Package: B
# Synthetic: package initializer
func init():
0: entry P:0 S:0
*i = 42:int
return
`},
}
for _, test := range tests {
// Create a single-file main package.
var conf loader.Config
f, err := conf.ParseFile("<input>", test.input)
if err != nil {
t.Errorf("test %q: %s", test.input[:15], err)
continue
}
conf.CreateFromFiles(f.Name.Name, f)
lprog, err := conf.Load()
if err != nil {
t.Errorf("test 'package %s': Load: %s", f.Name.Name, err)
continue
}
prog := ssautil.CreateProgram(lprog, test.mode)
mainPkg := prog.Package(lprog.Created[0].Pkg)
prog.Build()
initFunc := mainPkg.Func("init")
if initFunc == nil {
t.Errorf("test 'package %s': no init function", f.Name.Name)
continue
}
var initbuf bytes.Buffer
_, err = initFunc.WriteTo(&initbuf)
if err != nil {
t.Errorf("test 'package %s': WriteTo: %s", f.Name.Name, err)
continue
}
if initbuf.String() != test.want {
t.Errorf("test 'package %s': got %s, want %s", f.Name.Name, initbuf.String(), test.want)
}
}
}
// TestSyntheticFuncs checks that the expected synthetic functions are
// created, reachable, and not duplicated.
func TestSyntheticFuncs(t *testing.T) {
const input = `package P
type T int
func (T) f() int
func (*T) g() int
var (
// thunks
a = T.f
b = T.f
c = (struct{T}).f
d = (struct{T}).f
e = (*T).g
f = (*T).g
g = (struct{*T}).g
h = (struct{*T}).g
// bounds
i = T(0).f
j = T(0).f
k = new(T).g
l = new(T).g
// wrappers
m interface{} = struct{T}{}
n interface{} = struct{T}{}
o interface{} = struct{*T}{}
p interface{} = struct{*T}{}
q interface{} = new(struct{T})
r interface{} = new(struct{T})
s interface{} = new(struct{*T})
t interface{} = new(struct{*T})
)
`
// Parse
var conf loader.Config
f, err := conf.ParseFile("<input>", input)
if err != nil {
t.Fatalf("parse: %v", err)
}
conf.CreateFromFiles(f.Name.Name, f)
// Load
lprog, err := conf.Load()
if err != nil {
t.Fatalf("Load: %v", err)
}
// Create and build SSA
prog := ssautil.CreateProgram(lprog, 0)
prog.Build()
// Enumerate reachable synthetic functions
want := map[string]string{
"(*P.T).g$bound": "bound method wrapper for func (*P.T).g() int",
"(P.T).f$bound": "bound method wrapper for func (P.T).f() int",
"(*P.T).g$thunk": "thunk for func (*P.T).g() int",
"(P.T).f$thunk": "thunk for func (P.T).f() int",
"(struct{*P.T}).g$thunk": "thunk for func (*P.T).g() int",
"(struct{P.T}).f$thunk": "thunk for func (P.T).f() int",
"(*P.T).f": "wrapper for func (P.T).f() int",
"(*struct{*P.T}).f": "wrapper for func (P.T).f() int",
"(*struct{*P.T}).g": "wrapper for func (*P.T).g() int",
"(*struct{P.T}).f": "wrapper for func (P.T).f() int",
"(*struct{P.T}).g": "wrapper for func (*P.T).g() int",
"(struct{*P.T}).f": "wrapper for func (P.T).f() int",
"(struct{*P.T}).g": "wrapper for func (*P.T).g() int",
"(struct{P.T}).f": "wrapper for func (P.T).f() int",
"P.init": "package initializer",
}
for fn := range ssautil.AllFunctions(prog) {
if fn.Synthetic == "" {
continue
}
name := fn.String()
wantDescr, ok := want[name]
if !ok {
t.Errorf("got unexpected/duplicate func: %q: %q", name, fn.Synthetic)
continue
}
delete(want, name)
if wantDescr != fn.Synthetic {
t.Errorf("(%s).Synthetic = %q, want %q", name, fn.Synthetic, wantDescr)
}
}
for fn, descr := range want {
t.Errorf("want func: %q: %q", fn, descr)
}
}
// TestPhiElimination ensures that dead phis, including those that
// participate in a cycle, are properly eliminated.
func TestPhiElimination(t *testing.T) {
const input = `
package p
func f() error
func g(slice []int) {
for {
for range slice {
// e should not be lifted to a dead φ-node.
e := f()
h(e)
}
}
}
func h(error)
`
// The SSA code for this function should look something like this:
// 0:
// jump 1
// 1:
// t0 = len(slice)
// jump 2
// 2:
// t1 = phi [1: -1:int, 3: t2]
// t2 = t1 + 1:int
// t3 = t2 < t0
// if t3 goto 3 else 1
// 3:
// t4 = f()
// t5 = h(t4)
// jump 2
//
// But earlier versions of the SSA construction algorithm would
// additionally generate this cycle of dead phis:
//
// 1:
// t7 = phi [0: nil:error, 2: t8] #e
// ...
// 2:
// t8 = phi [1: t7, 3: t4] #e
// ...
// Parse
var conf loader.Config
f, err := conf.ParseFile("<input>", input)
if err != nil {
t.Fatalf("parse: %v", err)
}
conf.CreateFromFiles("p", f)
// Load
lprog, err := conf.Load()
if err != nil {
t.Fatalf("Load: %v", err)
}
// Create and build SSA
prog := ssautil.CreateProgram(lprog, 0)
p := prog.Package(lprog.Package("p").Pkg)
p.Build()
g := p.Func("g")
phis := 0
for _, b := range g.Blocks {
for _, instr := range b.Instrs {
if _, ok := instr.(*ssa.Phi); ok {
phis++
}
}
}
if phis != 1 {
g.WriteTo(os.Stderr)
t.Errorf("expected a single Phi (for the range index), got %d", phis)
}
}