// emitImplicitSelections emits to f code to apply the sequence of
// implicit field selections specified by indices to base value v, and
// returns the selected value.
//
// If v is the address of a struct, the result will be the address of
// a field; if it is the value of a struct, the result will be the
// value of a field.
//
func emitImplicitSelections(f *Function, v Value, indices []int) Value {
for _, index := range indices {
fld := deref(v.Type()).Underlying().(*types.Struct).Field(index)
if isPointer(v.Type()) {
instr := &FieldAddr{
X: v,
Field: index,
}
instr.setType(types.NewPointer(fld.Type()))
v = f.emit(instr)
// Load the field's value iff indirectly embedded.
if isPointer(fld.Type()) {
v = emitLoad(f, v)
}
} else {
instr := &Field{
X: v,
Field: index,
}
instr.setType(fld.Type())
v = f.emit(instr)
}
}
return v
}
// emitNew emits to f a new (heap Alloc) instruction allocating an
// object of type typ. pos is the optional source location.
//
func emitNew(f *Function, typ types.Type, pos token.Pos) *Alloc {
v := &Alloc{Heap: true}
v.setType(types.NewPointer(typ))
v.setPos(pos)
f.emit(v)
return v
}
// emitFieldSelection emits to f code to select the index'th field of v.
//
// If wantAddr, the input must be a pointer-to-struct and the result
// will be the field's address; otherwise the result will be the
// field's value.
// Ident id is used for position and debug info.
//
func emitFieldSelection(f *Function, v Value, index int, wantAddr bool, id *ast.Ident) Value {
fld := deref(v.Type()).Underlying().(*types.Struct).Field(index)
if isPointer(v.Type()) {
instr := &FieldAddr{
X: v,
Field: index,
}
instr.setPos(id.Pos())
instr.setType(types.NewPointer(fld.Type()))
v = f.emit(instr)
// Load the field's value iff we don't want its address.
if !wantAddr {
v = emitLoad(f, v)
}
} else {
instr := &Field{
X: v,
Field: index,
}
instr.setPos(id.Pos())
instr.setType(fld.Type())
v = f.emit(instr)
}
emitDebugRef(f, id, v, wantAddr)
return v
}
// addLocal creates an anonymous local variable of type typ, adds it
// to function f and returns it. pos is the optional source location.
//
func (f *Function) addLocal(typ types.Type, pos token.Pos) *Alloc {
v := &Alloc{}
v.setType(types.NewPointer(typ))
v.setPos(pos)
f.Locals = append(f.Locals, v)
f.emit(v)
return v
}
// addSpilledParam declares a parameter that is pre-spilled to the
// stack; the function body will load/store the spilled location.
// Subsequent lifting will eliminate spills where possible.
//
func (f *Function) addSpilledParam(obj types.Object) {
param := f.addParamObj(obj)
spill := &Alloc{Comment: obj.Name()}
spill.setType(types.NewPointer(obj.Type()))
spill.setPos(obj.Pos())
f.objects[obj] = spill
f.Locals = append(f.Locals, spill)
f.emit(spill)
f.emit(&Store{Addr: spill, Val: param})
}
// testMainSlice emits to fn code to construct a slice of type slice
// (one of []testing.Internal{Test,Benchmark,Example}) for all
// functions in testfuncs. It returns the slice value.
//
func testMainSlice(fn *Function, testfuncs []*Function, slice types.Type) Value {
if testfuncs == nil {
return nilConst(slice)
}
tElem := slice.(*types.Slice).Elem()
tPtrString := types.NewPointer(tString)
tPtrElem := types.NewPointer(tElem)
tPtrFunc := types.NewPointer(funcField(slice))
// Emit: array = new [n]testing.InternalTest
tArray := types.NewArray(tElem, int64(len(testfuncs)))
array := emitNew(fn, tArray, token.NoPos)
array.Comment = "test main"
for i, testfunc := range testfuncs {
// Emit: pitem = &array[i]
ia := &IndexAddr{X: array, Index: intConst(int64(i))}
ia.setType(tPtrElem)
pitem := fn.emit(ia)
// Emit: pname = &pitem.Name
fa := &FieldAddr{X: pitem, Field: 0} // .Name
fa.setType(tPtrString)
pname := fn.emit(fa)
// Emit: *pname = "testfunc"
emitStore(fn, pname, stringConst(testfunc.Name()), token.NoPos)
// Emit: pfunc = &pitem.F
fa = &FieldAddr{X: pitem, Field: 1} // .F
fa.setType(tPtrFunc)
pfunc := fn.emit(fa)
// Emit: *pfunc = testfunc
emitStore(fn, pfunc, testfunc, token.NoPos)
}
// Emit: slice array[:]
sl := &Slice{X: array}
sl.setType(slice)
return fn.emit(sl)
}
// memberFromObject populates package pkg with a member for the
// typechecker object obj.
//
// For objects from Go source code, syntax is the associated syntax
// tree (for funcs and vars only); it will be used during the build
// phase.
//
func memberFromObject(pkg *Package, obj types.Object, syntax ast.Node) {
name := obj.Name()
switch obj := obj.(type) {
case *types.TypeName:
pkg.Members[name] = &Type{
object: obj,
pkg: pkg,
}
case *types.Const:
c := &NamedConst{
object: obj,
Value: NewConst(obj.Val(), obj.Type()),
pkg: pkg,
}
pkg.values[obj] = c.Value
pkg.Members[name] = c
case *types.Var:
g := &Global{
Pkg: pkg,
name: name,
object: obj,
typ: types.NewPointer(obj.Type()), // address
pos: obj.Pos(),
}
pkg.values[obj] = g
pkg.Members[name] = g
case *types.Func:
fn := &Function{
name: name,
object: obj,
Signature: obj.Type().(*types.Signature),
syntax: syntax,
pos: obj.Pos(),
Pkg: pkg,
Prog: pkg.Prog,
}
if syntax == nil {
fn.Synthetic = "loaded from gc object file"
}
pkg.values[obj] = fn
if fn.Signature.Recv() == nil {
pkg.Members[name] = fn // package-level function
}
default: // (incl. *types.Package)
panic("unexpected Object type: " + obj.String())
}
}
// Type =
// BasicType | TypeName | ArrayType | SliceType | StructType |
// PointerType | FuncType | InterfaceType | MapType | ChanType |
// "(" Type ")" .
//
// BasicType = ident .
// TypeName = ExportedName .
// SliceType = "[" "]" Type .
// PointerType = "*" Type .
// FuncType = "func" Signature .
//
func (p *parser) parseType() types.Type {
switch p.tok {
case scanner.Ident:
switch p.lit {
default:
return p.parseBasicType()
case "struct":
return p.parseStructType()
case "func":
// FuncType
p.next()
return p.parseSignature(nil)
case "interface":
return p.parseInterfaceType()
case "map":
return p.parseMapType()
case "chan":
return p.parseChanType()
}
case '@':
// TypeName
pkg, name := p.parseExportedName()
return declTypeName(pkg, name).Type()
case '[':
p.next() // look ahead
if p.tok == ']' {
// SliceType
p.next()
return types.NewSlice(p.parseType())
}
return p.parseArrayType()
case '*':
// PointerType
p.next()
return types.NewPointer(p.parseType())
case '<':
return p.parseChanType()
case '(':
// "(" Type ")"
p.next()
typ := p.parseType()
p.expect(')')
return typ
}
p.errorf("expected type, got %s (%q)", scanner.TokenString(p.tok), p.lit)
return nil
}
// IntuitiveMethodSet returns the intuitive method set of a type, T.
//
// The result contains MethodSet(T) and additionally, if T is a
// concrete type, methods belonging to *T if there is no identically
// named method on T itself. This corresponds to user intuition about
// method sets; this function is intended only for user interfaces.
//
// The order of the result is as for types.MethodSet(T).
//
func IntuitiveMethodSet(T types.Type, msets *types.MethodSetCache) []*types.Selection {
var result []*types.Selection
mset := msets.MethodSet(T)
if _, ok := T.Underlying().(*types.Interface); ok {
for i, n := 0, mset.Len(); i < n; i++ {
result = append(result, mset.At(i))
}
} else {
pmset := msets.MethodSet(types.NewPointer(T))
for i, n := 0, pmset.Len(); i < n; i++ {
meth := pmset.At(i)
if m := mset.Lookup(meth.Obj().Pkg(), meth.Obj().Name()); m != nil {
meth = m
}
result = append(result, meth)
}
}
return result
}
// Smoke test to ensure that imported methods get the correct package.
func TestCorrectMethodPackage(t *testing.T) {
// This package does not handle gccgo export data.
if runtime.Compiler == "gccgo" {
return
}
imports := make(map[string]*types.Package)
_, err := Import(imports, "net/http")
if err != nil {
t.Fatal(err)
}
mutex := imports["sync"].Scope().Lookup("Mutex").(*types.TypeName).Type()
mset := types.NewMethodSet(types.NewPointer(mutex)) // methods of *sync.Mutex
sel := mset.Lookup(nil, "Lock")
lock := sel.Obj().(*types.Func)
if got, want := lock.Pkg().Path(), "sync"; got != want {
t.Errorf("got package path %q; want %q", got, want)
}
}
// findNamedFunc returns the named function whose FuncDecl.Ident is at
// position pos.
//
func findNamedFunc(pkg *Package, pos token.Pos) *Function {
// Look at all package members and method sets of named types.
// Not very efficient.
for _, mem := range pkg.Members {
switch mem := mem.(type) {
case *Function:
if mem.Pos() == pos {
return mem
}
case *Type:
mset := pkg.Prog.MethodSets.MethodSet(types.NewPointer(mem.Type()))
for i, n := 0, mset.Len(); i < n; i++ {
// Don't call Program.Method: avoid creating wrappers.
obj := mset.At(i).Obj().(*types.Func)
if obj.Pos() == pos {
return pkg.values[obj].(*Function)
}
}
}
}
return nil
}
func checkVarValue(t *testing.T, prog *ssa.Program, pkg *ssa.Package, ref []ast.Node, obj *types.Var, expKind string, wantAddr bool) {
// The prefix of all assertions messages.
prefix := fmt.Sprintf("VarValue(%s @ L%d)",
obj, prog.Fset.Position(ref[0].Pos()).Line)
v, gotAddr := prog.VarValue(obj, pkg, ref)
// Kind is the concrete type of the ssa Value.
gotKind := "nil"
if v != nil {
gotKind = fmt.Sprintf("%T", v)[len("*ssa."):]
}
// fmt.Printf("%s = %v (kind %q; expect %q) wantAddr=%t gotAddr=%t\n", prefix, v, gotKind, expKind, wantAddr, gotAddr) // debugging
// Check the kinds match.
// "nil" indicates expected failure (e.g. optimized away).
if expKind != gotKind {
t.Errorf("%s concrete type == %s, want %s", prefix, gotKind, expKind)
}
// Check the types match.
// If wantAddr, the expected type is the object's address.
if v != nil {
expType := obj.Type()
if wantAddr {
expType = types.NewPointer(expType)
if !gotAddr {
t.Errorf("%s: got value, want address", prefix)
}
} else if gotAddr {
t.Errorf("%s: got address, want value", prefix)
}
if !types.Identical(v.Type(), expType) {
t.Errorf("%s.Type() == %s, want %s", prefix, v.Type(), expType)
}
}
}
// TODO(adonovan):
// - test use of explicit hasher across two maps.
// - test hashcodes are consistent with equals for a range of types
// (e.g. all types generated by type-checking some body of real code).
import (
"testing"
"github.com/fzipp/pythia/internal/tools/go/types"
"github.com/fzipp/pythia/internal/tools/go/types/typeutil"
)
var (
tStr = types.Typ[types.String] // string
tPStr1 = types.NewPointer(tStr) // *string
tPStr2 = types.NewPointer(tStr) // *string, again
tInt = types.Typ[types.Int] // int
tChanInt1 = types.NewChan(types.RecvOnly, tInt) // <-chan int
tChanInt2 = types.NewChan(types.RecvOnly, tInt) // <-chan int, again
)
func checkEqualButNotIdentical(t *testing.T, x, y types.Type, comment string) {
if !types.Identical(x, y) {
t.Errorf("%s: not equal: %s, %s", comment, x, y)
}
if x == y {
t.Errorf("%s: identical: %v, %v", comment, x, y)
}
}
// Tests that programs partially loaded from gc object files contain
// functions with no code for the external portions, but are otherwise ok.
func TestImportFromBinary(t *testing.T) {
test := `
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
}
`
// Create a single-file main package.
conf := loader.Config{ImportFromBinary: true}
f, err := conf.ParseFile("<input>", test)
if err != nil {
t.Error(err)
return
}
conf.CreateFromFiles("main", f)
iprog, err := conf.Load()
if err != nil {
t.Error(err)
return
}
prog := ssa.Create(iprog, ssa.SanityCheckFunctions)
mainPkg := prog.Package(iprog.Created[0].Pkg)
mainPkg.Build()
// The main package, its direct and indirect dependencies are loaded.
deps := []string{
// directly imported dependencies:
"bytes", "io", "testing",
// indirect dependencies (partial list):
"errors", "fmt", "os", "runtime",
}
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.Method(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)
}
}
// CreatePackage constructs and returns an SSA Package from an
// error-free package described by info, and populates its Members
// mapping.
//
// Repeated calls with the same info return the same Package.
//
// The real work of building SSA form for each function is not done
// until a subsequent call to Package.Build().
//
func (prog *Program) CreatePackage(info *loader.PackageInfo) *Package {
if p := prog.packages[info.Pkg]; p != nil {
return p // already loaded
}
p := &Package{
Prog: prog,
Members: make(map[string]Member),
values: make(map[types.Object]Value),
Object: info.Pkg,
info: info, // transient (CREATE and BUILD phases)
}
// Add init() function.
p.init = &Function{
name: "init",
Signature: new(types.Signature),
Synthetic: "package initializer",
Pkg: p,
Prog: prog,
}
p.Members[p.init.name] = p.init
// CREATE phase.
// Allocate all package members: vars, funcs, consts and types.
if len(info.Files) > 0 {
// Go source package.
for _, file := range info.Files {
for _, decl := range file.Decls {
membersFromDecl(p, decl)
}
}
} else {
// GC-compiled binary package.
// No code.
// No position information.
scope := p.Object.Scope()
for _, name := range scope.Names() {
obj := scope.Lookup(name)
memberFromObject(p, obj, nil)
if obj, ok := obj.(*types.TypeName); ok {
named := obj.Type().(*types.Named)
for i, n := 0, named.NumMethods(); i < n; i++ {
memberFromObject(p, named.Method(i), nil)
}
}
}
}
if prog.mode&BareInits == 0 {
// Add initializer guard variable.
initguard := &Global{
Pkg: p,
name: "init$guard",
typ: types.NewPointer(tBool),
}
p.Members[initguard.Name()] = initguard
}
if prog.mode&GlobalDebug != 0 {
p.SetDebugMode(true)
}
if prog.mode&PrintPackages != 0 {
printMu.Lock()
p.WriteTo(os.Stdout)
printMu.Unlock()
}
if info.Importable {
prog.imported[info.Pkg.Path()] = p
}
prog.packages[p.Object] = p
return p
}
// Implements displays the "implements" relation as it pertains to the
// selected type. If the selection is a method, 'implements' displays
// the corresponding methods of the types that would have been reported
// by an implements query on the receiver type.
//
func implements(o *Oracle, qpos *QueryPos) (queryResult, error) {
// Find the selected type.
path, action := findInterestingNode(qpos.info, qpos.path)
var method *types.Func
var T types.Type // selected type (receiver if method != nil)
switch action {
case actionExpr:
// method?
if id, ok := path[0].(*ast.Ident); ok {
if obj, ok := qpos.info.ObjectOf(id).(*types.Func); ok {
recv := obj.Type().(*types.Signature).Recv()
if recv == nil {
return nil, fmt.Errorf("this function is not a method")
}
method = obj
T = recv.Type()
}
}
case actionType:
T = qpos.info.TypeOf(path[0].(ast.Expr))
}
if T == nil {
return nil, fmt.Errorf("no type or method here")
}
// Find all named types, even local types (which can have
// methods via promotion) and the built-in "error".
//
// TODO(adonovan): include all packages in PTA scope too?
// i.e. don't reduceScope?
//
var allNamed []types.Type
for _, info := range o.typeInfo {
for _, obj := range info.Defs {
if obj, ok := obj.(*types.TypeName); ok {
allNamed = append(allNamed, obj.Type())
}
}
}
allNamed = append(allNamed, types.Universe.Lookup("error").Type())
var msets types.MethodSetCache
// Test each named type.
var to, from, fromPtr []types.Type
for _, U := range allNamed {
if isInterface(T) {
if msets.MethodSet(T).Len() == 0 {
continue // empty interface
}
if isInterface(U) {
if msets.MethodSet(U).Len() == 0 {
continue // empty interface
}
// T interface, U interface
if !types.Identical(T, U) {
if types.AssignableTo(U, T) {
to = append(to, U)
}
if types.AssignableTo(T, U) {
from = append(from, U)
}
}
} else {
// T interface, U concrete
if types.AssignableTo(U, T) {
to = append(to, U)
} else if pU := types.NewPointer(U); types.AssignableTo(pU, T) {
to = append(to, pU)
}
}
} else if isInterface(U) {
if msets.MethodSet(U).Len() == 0 {
continue // empty interface
}
// T concrete, U interface
if types.AssignableTo(T, U) {
from = append(from, U)
} else if pT := types.NewPointer(T); types.AssignableTo(pT, U) {
fromPtr = append(fromPtr, U)
}
}
}
var pos interface{} = qpos
if nt, ok := deref(T).(*types.Named); ok {
pos = nt.Obj()
}
// Sort types (arbitrarily) to ensure test determinism.
sort.Sort(typesByString(to))
sort.Sort(typesByString(from))
sort.Sort(typesByString(fromPtr))
var toMethod, fromMethod, fromPtrMethod []*types.Selection // contain nils
if method != nil {
for _, t := range to {
toMethod = append(toMethod,
types.NewMethodSet(t).Lookup(method.Pkg(), method.Name()))
}
for _, t := range from {
fromMethod = append(fromMethod,
types.NewMethodSet(t).Lookup(method.Pkg(), method.Name()))
}
for _, t := range fromPtr {
fromPtrMethod = append(fromPtrMethod,
types.NewMethodSet(t).Lookup(method.Pkg(), method.Name()))
}
}
return &implementsResult{qpos, T, pos, to, from, fromPtr, method, toMethod, fromMethod, fromPtrMethod}, nil
}
// Precondition: T is not a method signature (*Signature with Recv()!=nil).
// Recursive case: skip => don't create methods for T.
//
// EXCLUSIVE_LOCKS_REQUIRED(prog.methodsMu)
//
func (prog *Program) needMethods(T types.Type, skip bool) {
// Each package maintains its own set of types it has visited.
if prevSkip, ok := prog.runtimeTypes.At(T).(bool); ok {
// needMethods(T) was previously called
if !prevSkip || skip {
return // already seen, with same or false 'skip' value
}
}
prog.runtimeTypes.Set(T, skip)
tmset := prog.MethodSets.MethodSet(T)
if !skip && !isInterface(T) && tmset.Len() > 0 {
// Create methods of T.
mset := prog.createMethodSet(T)
if !mset.complete {
mset.complete = true
n := tmset.Len()
for i := 0; i < n; i++ {
prog.addMethod(mset, tmset.At(i))
}
}
}
// Recursion over signatures of each method.
for i := 0; i < tmset.Len(); i++ {
sig := tmset.At(i).Type().(*types.Signature)
prog.needMethods(sig.Params(), false)
prog.needMethods(sig.Results(), false)
}
switch t := T.(type) {
case *types.Basic:
// nop
case *types.Interface:
// nop---handled by recursion over method set.
case *types.Pointer:
prog.needMethods(t.Elem(), false)
case *types.Slice:
prog.needMethods(t.Elem(), false)
case *types.Chan:
prog.needMethods(t.Elem(), false)
case *types.Map:
prog.needMethods(t.Key(), false)
prog.needMethods(t.Elem(), false)
case *types.Signature:
if t.Recv() != nil {
panic(fmt.Sprintf("Signature %s has Recv %s", t, t.Recv()))
}
prog.needMethods(t.Params(), false)
prog.needMethods(t.Results(), false)
case *types.Named:
// A pointer-to-named type can be derived from a named
// type via reflection. It may have methods too.
prog.needMethods(types.NewPointer(T), false)
// Consider 'type T struct{S}' where S has methods.
// Reflection provides no way to get from T to struct{S},
// only to S, so the method set of struct{S} is unwanted,
// so set 'skip' flag during recursion.
prog.needMethods(t.Underlying(), true)
case *types.Array:
prog.needMethods(t.Elem(), false)
case *types.Struct:
for i, n := 0, t.NumFields(); i < n; i++ {
prog.needMethods(t.Field(i).Type(), false)
}
case *types.Tuple:
for i, n := 0, t.Len(); i < n; i++ {
prog.needMethods(t.At(i).Type(), false)
}
default:
panic(T)
}
}
func ext۰reflect۰New(fr *frame, args []value) value {
// Signature: func (t reflect.Type) reflect.Value
t := args[0].(iface).v.(rtype).t
alloc := zero(t)
return makeReflectValue(types.NewPointer(t), &alloc)
}
// addRuntimeType is called for each concrete type that can be the
// dynamic type of some interface or reflect.Value.
// Adapted from needMethods in go/ssa/builder.go
//
func (r *rta) addRuntimeType(T types.Type, skip bool) {
if prev, ok := r.result.RuntimeTypes.At(T).(bool); ok {
if skip && !prev {
r.result.RuntimeTypes.Set(T, skip)
}
return
}
r.result.RuntimeTypes.Set(T, skip)
mset := r.prog.MethodSets.MethodSet(T)
if _, ok := T.Underlying().(*types.Interface); !ok {
// T is a new concrete type.
for i, n := 0, mset.Len(); i < n; i++ {
sel := mset.At(i)
m := sel.Obj()
if m.Exported() {
// Exported methods are always potentially callable via reflection.
r.addReachable(r.prog.Method(sel), true)
}
}
// Add callgraph edge for each existing dynamic
// "invoke"-mode call via that interface.
for _, I := range r.interfaces(T) {
sites, _ := r.invokeSites.At(I).([]ssa.CallInstruction)
for _, site := range sites {
r.addInvokeEdge(site, T)
}
}
}
// Precondition: T is not a method signature (*Signature with Recv()!=nil).
// Recursive case: skip => don't call makeMethods(T).
// Each package maintains its own set of types it has visited.
var n *types.Named
switch T := T.(type) {
case *types.Named:
n = T
case *types.Pointer:
n, _ = T.Elem().(*types.Named)
}
if n != nil {
owner := n.Obj().Pkg()
if owner == nil {
return // built-in error type
}
}
// Recursion over signatures of each exported method.
for i := 0; i < mset.Len(); i++ {
if mset.At(i).Obj().Exported() {
sig := mset.At(i).Type().(*types.Signature)
r.addRuntimeType(sig.Params(), true) // skip the Tuple itself
r.addRuntimeType(sig.Results(), true) // skip the Tuple itself
}
}
switch t := T.(type) {
case *types.Basic:
// nop
case *types.Interface:
// nop---handled by recursion over method set.
case *types.Pointer:
r.addRuntimeType(t.Elem(), false)
case *types.Slice:
r.addRuntimeType(t.Elem(), false)
case *types.Chan:
r.addRuntimeType(t.Elem(), false)
case *types.Map:
r.addRuntimeType(t.Key(), false)
r.addRuntimeType(t.Elem(), false)
case *types.Signature:
if t.Recv() != nil {
panic(fmt.Sprintf("Signature %s has Recv %s", t, t.Recv()))
}
r.addRuntimeType(t.Params(), true) // skip the Tuple itself
r.addRuntimeType(t.Results(), true) // skip the Tuple itself
case *types.Named:
// A pointer-to-named type can be derived from a named
// type via reflection. It may have methods too.
r.addRuntimeType(types.NewPointer(T), false)
// Consider 'type T struct{S}' where S has methods.
// Reflection provides no way to get from T to struct{S},
// only to S, so the method set of struct{S} is unwanted,
// so set 'skip' flag during recursion.
r.addRuntimeType(t.Underlying(), true)
case *types.Array:
r.addRuntimeType(t.Elem(), false)
case *types.Struct:
for i, n := 0, t.NumFields(); i < n; i++ {
r.addRuntimeType(t.Field(i).Type(), false)
}
case *types.Tuple:
for i, n := 0, t.Len(); i < n; i++ {
r.addRuntimeType(t.At(i).Type(), false)
}
default:
panic(T)
}
}
// Analyze runs the pointer analysis with the scope and options
// specified by config, and returns the (synthetic) root of the callgraph.
//
// Pointer analysis of a transitively closed well-typed program should
// always succeed. An error can occur only due to an internal bug.
//
func Analyze(config *Config) (result *Result, err error) {
if config.Mains == nil {
return nil, fmt.Errorf("no main/test packages to analyze (check $GOROOT/$GOPATH)")
}
defer func() {
if p := recover(); p != nil {
err = fmt.Errorf("internal error in pointer analysis: %v (please report this bug)", p)
fmt.Fprintln(os.Stderr, "Internal panic in pointer analysis:")
debug.PrintStack()
}
}()
a := &analysis{
config: config,
log: config.Log,
prog: config.prog(),
globalval: make(map[ssa.Value]nodeid),
globalobj: make(map[ssa.Value]nodeid),
flattenMemo: make(map[types.Type][]*fieldInfo),
trackTypes: make(map[types.Type]bool),
atFuncs: make(map[*ssa.Function]bool),
hasher: typeutil.MakeHasher(),
intrinsics: make(map[*ssa.Function]intrinsic),
result: &Result{
Queries: make(map[ssa.Value]Pointer),
IndirectQueries: make(map[ssa.Value]Pointer),
},
deltaSpace: make([]int, 0, 100),
}
if false {
a.log = os.Stderr // for debugging crashes; extremely verbose
}
if a.log != nil {
fmt.Fprintln(a.log, "==== Starting analysis")
}
// Pointer analysis requires a complete program for soundness.
// Check to prevent accidental misconfiguration.
for _, pkg := range a.prog.AllPackages() {
// (This only checks that the package scope is complete,
// not that func bodies exist, but it's a good signal.)
if !pkg.Object.Complete() {
return nil, fmt.Errorf(`pointer analysis requires a complete program yet package %q was incomplete (don't set loader.Config.ImportFromBinary during loading)`, pkg.Object.Path())
}
}
if reflect := a.prog.ImportedPackage("reflect"); reflect != nil {
rV := reflect.Object.Scope().Lookup("Value")
a.reflectValueObj = rV
a.reflectValueCall = a.prog.LookupMethod(rV.Type(), nil, "Call")
a.reflectType = reflect.Object.Scope().Lookup("Type").Type().(*types.Named)
a.reflectRtypeObj = reflect.Object.Scope().Lookup("rtype")
a.reflectRtypePtr = types.NewPointer(a.reflectRtypeObj.Type())
// Override flattening of reflect.Value, treating it like a basic type.
tReflectValue := a.reflectValueObj.Type()
a.flattenMemo[tReflectValue] = []*fieldInfo{{typ: tReflectValue}}
// Override shouldTrack of reflect.Value and *reflect.rtype.
// Always track pointers of these types.
a.trackTypes[tReflectValue] = true
a.trackTypes[a.reflectRtypePtr] = true
a.rtypes.SetHasher(a.hasher)
a.reflectZeros.SetHasher(a.hasher)
}
if runtime := a.prog.ImportedPackage("runtime"); runtime != nil {
a.runtimeSetFinalizer = runtime.Func("SetFinalizer")
}
a.computeTrackBits()
a.generate()
a.showCounts()
if optRenumber {
a.renumber()
}
N := len(a.nodes) // excludes solver-created nodes
if optHVN {
if debugHVNCrossCheck {
// Cross-check: run the solver once without
// optimization, once with, and compare the
// solutions.
savedConstraints := a.constraints
a.solve()
a.dumpSolution("A.pts", N)
// Restore.
a.constraints = savedConstraints
for _, n := range a.nodes {
n.solve = new(solverState)
}
a.nodes = a.nodes[:N]
// rtypes is effectively part of the solver state.
a.rtypes = typeutil.Map{}
a.rtypes.SetHasher(a.hasher)
}
a.hvn()
}
if debugHVNCrossCheck {
runtime.GC()
runtime.GC()
}
a.solve()
// Compare solutions.
if optHVN && debugHVNCrossCheck {
a.dumpSolution("B.pts", N)
if !diff("A.pts", "B.pts") {
return nil, fmt.Errorf("internal error: optimization changed solution")
}
}
// Create callgraph.Nodes in deterministic order.
if cg := a.result.CallGraph; cg != nil {
for _, caller := range a.cgnodes {
cg.CreateNode(caller.fn)
}
}
// Add dynamic edges to call graph.
var space [100]int
for _, caller := range a.cgnodes {
for _, site := range caller.sites {
for _, callee := range a.nodes[site.targets].solve.pts.AppendTo(space[:0]) {
a.callEdge(caller, site, nodeid(callee))
}
}
}
return a.result, nil
}
// computeImplements computes the "implements" relation over all pairs
// of named types in allNamed.
func computeImplements(cache *types.MethodSetCache, allNamed []*types.Named) map[*types.Named]implementsFacts {
// Information about a single type's method set.
type msetInfo struct {
typ types.Type
mset *types.MethodSet
mask1, mask2 uint64
}
initMsetInfo := func(info *msetInfo, typ types.Type) {
info.typ = typ
info.mset = cache.MethodSet(typ)
for i := 0; i < info.mset.Len(); i++ {
name := info.mset.At(i).Obj().Name()
info.mask1 |= 1 << methodBit(name[0])
info.mask2 |= 1 << methodBit(name[len(name)-1])
}
}
// satisfies(T, U) reports whether type T satisfies type U.
// U must be an interface.
//
// Since there are thousands of types (and thus millions of
// pairs of types) and types.Assignable(T, U) is relatively
// expensive, we compute assignability directly from the
// method sets. (At least one of T and U must be an
// interface.)
//
// We use a trick (thanks gri!) related to a Bloom filter to
// quickly reject most tests, which are false. For each
// method set, we precompute a mask, a set of bits, one per
// distinct initial byte of each method name. Thus the mask
// for io.ReadWriter would be {'R','W'}. AssignableTo(T, U)
// cannot be true unless mask(T)&mask(U)==mask(U).
//
// As with a Bloom filter, we can improve precision by testing
// additional hashes, e.g. using the last letter of each
// method name, so long as the subset mask property holds.
//
// When analyzing the standard library, there are about 1e6
// calls to satisfies(), of which 0.6% return true. With a
// 1-hash filter, 95% of calls avoid the expensive check; with
// a 2-hash filter, this grows to 98.2%.
satisfies := func(T, U *msetInfo) bool {
return T.mask1&U.mask1 == U.mask1 &&
T.mask2&U.mask2 == U.mask2 &&
containsAllIdsOf(T.mset, U.mset)
}
// Information about a named type N, and perhaps also *N.
type namedInfo struct {
isInterface bool
base msetInfo // N
ptr msetInfo // *N, iff N !isInterface
}
var infos []namedInfo
// Precompute the method sets and their masks.
for _, N := range allNamed {
var info namedInfo
initMsetInfo(&info.base, N)
_, info.isInterface = N.Underlying().(*types.Interface)
if !info.isInterface {
initMsetInfo(&info.ptr, types.NewPointer(N))
}
if info.base.mask1|info.ptr.mask1 == 0 {
continue // neither N nor *N has methods
}
infos = append(infos, info)
}
facts := make(map[*types.Named]implementsFacts)
// Test all pairs of distinct named types (T, U).
// TODO(adonovan): opt: compute (U, T) at the same time.
for t := range infos {
T := &infos[t]
var to, from, fromPtr []types.Type
for u := range infos {
if t == u {
continue
}
U := &infos[u]
switch {
case T.isInterface && U.isInterface:
if satisfies(&U.base, &T.base) {
to = append(to, U.base.typ)
}
if satisfies(&T.base, &U.base) {
from = append(from, U.base.typ)
}
case T.isInterface: // U concrete
if satisfies(&U.base, &T.base) {
to = append(to, U.base.typ)
} else if satisfies(&U.ptr, &T.base) {
to = append(to, U.ptr.typ)
}
case U.isInterface: // T concrete
if satisfies(&T.base, &U.base) {
from = append(from, U.base.typ)
} else if satisfies(&T.ptr, &U.base) {
fromPtr = append(fromPtr, U.base.typ)
}
}
}
// Sort types (arbitrarily) to avoid nondeterminism.
sort.Sort(typesByString(to))
sort.Sort(typesByString(from))
sort.Sort(typesByString(fromPtr))
facts[T.base.typ.(*types.Named)] = implementsFacts{to, from, fromPtr}
}
return facts
}