// Signature = Parameters [ Result ] .
// Result = Type | Parameters .
//
func (p *parser) parseSignature(recv *types.Var) *types.Signature {
params, isVariadic := p.parseParameters()
// optional result type
var results []*types.Var
if p.tok == '(' {
var variadic bool
results, variadic = p.parseParameters()
if variadic {
p.error("... not permitted on result type")
}
}
return types.NewSignature(nil, recv, types.NewTuple(params...), types.NewTuple(results...), isVariadic)
}
// makeLen returns the len builtin specialized to type func(T)int.
func makeLen(T types.Type) *Builtin {
lenParams := types.NewTuple(anonVar(T))
return &Builtin{
name: "len",
sig: types.NewSignature(nil, nil, lenParams, lenResults, false),
}
}
// emitTypeTest emits to f a type test value,ok := x.(t) and returns
// a (value, ok) tuple. x.Type() must be an interface.
//
func emitTypeTest(f *Function, x Value, t types.Type, pos token.Pos) Value {
a := &TypeAssert{
X: x,
AssertedType: t,
CommaOk: true,
}
a.setPos(pos)
a.setType(types.NewTuple(
newVar("value", t),
varOk,
))
return f.emit(a)
}
// makeWrapper returns a synthetic method that delegates to the
// declared method denoted by meth.Obj(), first performing any
// necessary pointer indirections or field selections implied by meth.
//
// The resulting method's receiver type is meth.Recv().
//
// This function is versatile but quite subtle! Consider the
// following axes of variation when making changes:
// - optional receiver indirection
// - optional implicit field selections
// - meth.Obj() may denote a concrete or an interface method
// - the result may be a thunk or a wrapper.
//
// EXCLUSIVE_LOCKS_REQUIRED(prog.methodsMu)
//
func makeWrapper(prog *Program, sel *types.Selection) *Function {
obj := sel.Obj().(*types.Func) // the declared function
sig := sel.Type().(*types.Signature) // type of this wrapper
var recv *types.Var // wrapper's receiver or thunk's params[0]
name := obj.Name()
var description string
var start int // first regular param
if sel.Kind() == types.MethodExpr {
name += "$thunk"
description = "thunk"
recv = sig.Params().At(0)
start = 1
} else {
description = "wrapper"
recv = sig.Recv()
}
description = fmt.Sprintf("%s for %s", description, sel.Obj())
if prog.mode&LogSource != 0 {
defer logStack("make %s to (%s)", description, recv.Type())()
}
fn := &Function{
name: name,
method: sel,
object: obj,
Signature: sig,
Synthetic: description,
Prog: prog,
pos: obj.Pos(),
}
fn.startBody()
fn.addSpilledParam(recv)
createParams(fn, start)
indices := sel.Index()
var v Value = fn.Locals[0] // spilled receiver
if isPointer(sel.Recv()) {
v = emitLoad(fn, v)
// For simple indirection wrappers, perform an informative nil-check:
// "value method (T).f called using nil *T pointer"
if len(indices) == 1 && !isPointer(recvType(obj)) {
var c Call
c.Call.Value = &Builtin{
name: "ssa:wrapnilchk",
sig: types.NewSignature(nil, nil,
types.NewTuple(anonVar(sel.Recv()), anonVar(tString), anonVar(tString)),
types.NewTuple(anonVar(sel.Recv())), false),
}
c.Call.Args = []Value{
v,
stringConst(deref(sel.Recv()).String()),
stringConst(sel.Obj().Name()),
}
c.setType(v.Type())
v = fn.emit(&c)
}
}
// Invariant: v is a pointer, either
// value of *A receiver param, or
// address of A spilled receiver.
// We use pointer arithmetic (FieldAddr possibly followed by
// Load) in preference to value extraction (Field possibly
// preceded by Load).
v = emitImplicitSelections(fn, v, indices[:len(indices)-1])
// Invariant: v is a pointer, either
// value of implicit *C field, or
// address of implicit C field.
var c Call
if r := recvType(obj); !isInterface(r) { // concrete method
if !isPointer(r) {
v = emitLoad(fn, v)
}
c.Call.Value = prog.declaredFunc(obj)
c.Call.Args = append(c.Call.Args, v)
} else {
c.Call.Method = obj
c.Call.Value = emitLoad(fn, v)
}
for _, arg := range fn.Params[1:] {
c.Call.Args = append(c.Call.Args, arg)
}
emitTailCall(fn, &c)
fn.finishBody()
return fn
}
// CreateTestMainPackage creates and returns a synthetic "main"
// package that runs all the tests of the supplied packages, similar
// to the one that would be created by the 'go test' tool.
//
// It returns nil if the program contains no tests.
//
func (prog *Program) CreateTestMainPackage(pkgs ...*Package) *Package {
pkgs, tests, benchmarks, examples := FindTests(pkgs)
if len(pkgs) == 0 {
return nil
}
testmain := &Package{
Prog: prog,
Members: make(map[string]Member),
values: make(map[types.Object]Value),
Object: types.NewPackage("test$main", "main"),
}
// Build package's init function.
init := &Function{
name: "init",
Signature: new(types.Signature),
Synthetic: "package initializer",
Pkg: testmain,
Prog: prog,
}
init.startBody()
if testMainStartBodyHook != nil {
testMainStartBodyHook(init)
}
// Initialize packages to test.
var pkgpaths []string
for _, pkg := range pkgs {
var v Call
v.Call.Value = pkg.init
v.setType(types.NewTuple())
init.emit(&v)
pkgpaths = append(pkgpaths, pkg.Object.Path())
}
sort.Strings(pkgpaths)
init.emit(new(Return))
init.finishBody()
testmain.init = init
testmain.Object.MarkComplete()
testmain.Members[init.name] = init
// For debugging convenience, define an unexported const
// that enumerates the packages.
packagesConst := types.NewConst(token.NoPos, testmain.Object, "packages", tString,
exact.MakeString(strings.Join(pkgpaths, " ")))
memberFromObject(testmain, packagesConst, nil)
// Create main *types.Func and *ssa.Function
mainFunc := types.NewFunc(token.NoPos, testmain.Object, "main", new(types.Signature))
memberFromObject(testmain, mainFunc, nil)
main := testmain.Func("main")
main.Synthetic = "test main function"
main.startBody()
if testMainStartBodyHook != nil {
testMainStartBodyHook(main)
}
if testingPkg := prog.ImportedPackage("testing"); testingPkg != nil {
testingMain := testingPkg.Func("Main")
testingMainParams := testingMain.Signature.Params()
// The generated code is as if compiled from this:
//
// func main() {
// match := func(_, _ string) (bool, error) { return true, nil }
// tests := []testing.InternalTest{{"TestFoo", TestFoo}, ...}
// benchmarks := []testing.InternalBenchmark{...}
// examples := []testing.InternalExample{...}
// testing.Main(match, tests, benchmarks, examples)
// }
matcher := &Function{
name: "matcher",
Signature: testingMainParams.At(0).Type().(*types.Signature),
Synthetic: "test matcher predicate",
parent: main,
Pkg: testmain,
Prog: prog,
}
main.AnonFuncs = append(main.AnonFuncs, matcher)
matcher.startBody()
matcher.emit(&Return{Results: []Value{vTrue, nilConst(types.Universe.Lookup("error").Type())}})
matcher.finishBody()
// Emit call: testing.Main(matcher, tests, benchmarks, examples).
var c Call
c.Call.Value = testingMain
c.Call.Args = []Value{
matcher,
testMainSlice(main, tests, testingMainParams.At(1).Type()),
testMainSlice(main, benchmarks, testingMainParams.At(2).Type()),
testMainSlice(main, examples, testingMainParams.At(3).Type()),
}
emitTailCall(main, &c)
} else {
// The program does not import "testing", but FindTests
// returned non-nil, which must mean there were Examples
// but no Tests or Benchmarks.
// We'll simply call them from testmain.main; this will
// ensure they don't panic, but will not check any
// "Output:" comments.
for _, eg := range examples {
var c Call
c.Call.Value = eg
c.setType(types.NewTuple())
main.emit(&c)
}
main.emit(&Return{})
main.currentBlock = nil
}
main.finishBody()
testmain.Members["main"] = main
if prog.mode&PrintPackages != 0 {
printMu.Lock()
testmain.WriteTo(os.Stdout)
printMu.Unlock()
}
if prog.mode&SanityCheckFunctions != 0 {
sanityCheckPackage(testmain)
}
prog.packages[testmain.Object] = testmain
return testmain
}
func logStack(format string, args ...interface{}) func() {
msg := fmt.Sprintf(format, args...)
io.WriteString(os.Stderr, msg)
io.WriteString(os.Stderr, "\n")
return func() {
io.WriteString(os.Stderr, msg)
io.WriteString(os.Stderr, " end\n")
}
}
// newVar creates a 'var' for use in a types.Tuple.
func newVar(name string, typ types.Type) *types.Var {
return types.NewParam(token.NoPos, nil, name, typ)
}
// anonVar creates an anonymous 'var' for use in a types.Tuple.
func anonVar(typ types.Type) *types.Var {
return newVar("", typ)
}
var lenResults = types.NewTuple(anonVar(tInt))
// makeLen returns the len builtin specialized to type func(T)int.
func makeLen(T types.Type) *Builtin {
lenParams := types.NewTuple(anonVar(T))
return &Builtin{
name: "len",
sig: types.NewSignature(nil, nil, lenParams, lenResults, false),
}
}