// interfaces(C) returns all currently known interfaces implemented by C.
func (r *rta) interfaces(C types.Type) []*types.Interface {
// Ascertain set of interfaces C implements
// and update 'implements' relation.
var ifaces []*types.Interface
r.interfaceTypes.Iterate(func(I types.Type, concs interface{}) {
if I := I.(*types.Interface); types.Implements(C, I) {
concs, _ := concs.([]types.Type)
r.interfaceTypes.Set(I, append(concs, C))
ifaces = append(ifaces, I)
}
})
r.concreteTypes.Set(C, ifaces)
return ifaces
}
// implementations(I) returns all currently known concrete types that implement I.
func (r *rta) implementations(I *types.Interface) []types.Type {
var concs []types.Type
if v := r.interfaceTypes.At(I); v != nil {
concs = v.([]types.Type)
} else {
// First time seeing this interface.
// Update the 'implements' relation.
r.concreteTypes.Iterate(func(C types.Type, ifaces interface{}) {
if types.Implements(C, I) {
ifaces, _ := ifaces.([]*types.Interface)
r.concreteTypes.Set(C, append(ifaces, I))
concs = append(concs, C)
}
})
r.interfaceTypes.Set(I, concs)
}
return concs
}
// CallGraph computes the call graph of the specified program using the
// Class Hierarchy Analysis algorithm.
//
func CallGraph(prog *ssa.Program) *callgraph.Graph {
cg := callgraph.New(nil) // TODO(adonovan) eliminate concept of rooted callgraph
allFuncs := ssautil.AllFunctions(prog)
// funcsBySig contains all functions, keyed by signature. It is
// the effective set of address-taken functions used to resolve
// a dynamic call of a particular signature.
var funcsBySig typeutil.Map // value is []*ssa.Function
// methodsByName contains all methods,
// grouped by name for efficient lookup.
methodsByName := make(map[string][]*ssa.Function)
// methodsMemo records, for every abstract method call call I.f on
// interface type I, the set of concrete methods C.f of all
// types C that satisfy interface I.
methodsMemo := make(map[*types.Func][]*ssa.Function)
lookupMethods := func(m *types.Func) []*ssa.Function {
methods, ok := methodsMemo[m]
if !ok {
I := m.Type().(*types.Signature).Recv().Type().Underlying().(*types.Interface)
for _, f := range methodsByName[m.Name()] {
C := f.Signature.Recv().Type() // named or *named
if types.Implements(C, I) {
methods = append(methods, f)
}
}
methodsMemo[m] = methods
}
return methods
}
for f := range allFuncs {
if f.Signature.Recv() == nil {
// Package initializers can never be address-taken.
if f.Name() == "init" && f.Synthetic == "package initializer" {
continue
}
funcs, _ := funcsBySig.At(f.Signature).([]*ssa.Function)
funcs = append(funcs, f)
funcsBySig.Set(f.Signature, funcs)
} else {
methodsByName[f.Name()] = append(methodsByName[f.Name()], f)
}
}
addEdge := func(fnode *callgraph.Node, site ssa.CallInstruction, g *ssa.Function) {
gnode := cg.CreateNode(g)
callgraph.AddEdge(fnode, site, gnode)
}
addEdges := func(fnode *callgraph.Node, site ssa.CallInstruction, callees []*ssa.Function) {
// Because every call to a highly polymorphic and
// frequently used abstract method such as
// (io.Writer).Write is assumed to call every concrete
// Write method in the program, the call graph can
// contain a lot of duplication.
//
// TODO(adonovan): opt: consider factoring the callgraph
// API so that the Callers component of each edge is a
// slice of nodes, not a singleton.
for _, g := range callees {
addEdge(fnode, site, g)
}
}
for f := range allFuncs {
fnode := cg.CreateNode(f)
for _, b := range f.Blocks {
for _, instr := range b.Instrs {
if site, ok := instr.(ssa.CallInstruction); ok {
call := site.Common()
if call.IsInvoke() {
addEdges(fnode, site, lookupMethods(call.Method))
} else if g := call.StaticCallee(); g != nil {
addEdge(fnode, site, g)
} else if _, ok := call.Value.(*ssa.Builtin); !ok {
callees, _ := funcsBySig.At(call.Signature()).([]*ssa.Function)
addEdges(fnode, site, callees)
}
}
}
}
}
return cg
}
func isErrorType(t types.Type) bool {
return types.Implements(t, errorType)
}
// matchArgTypeInternal is the internal version of matchArgType. It carries a map
// remembering what types are in progress so we don't recur when faced with recursive
// types or mutually recursive types.
func (f *File) matchArgTypeInternal(t printfArgType, typ types.Type, arg ast.Expr, inProgress map[types.Type]bool) bool {
// %v, %T accept any argument type.
if t == anyType {
return true
}
if typ == nil {
// external call
typ = f.pkg.types[arg].Type
if typ == nil {
return true // probably a type check problem
}
}
// If the type implements fmt.Formatter, we have nothing to check.
// formatterTyp may be nil - be conservative and check for Format method in that case.
if formatterType != nil && types.Implements(typ, formatterType) || f.hasMethod(typ, "Format") {
return true
}
// If we can use a string, might arg (dynamically) implement the Stringer or Error interface?
if t&argString != 0 {
if types.AssertableTo(errorType, typ) || stringerType != nil && types.AssertableTo(stringerType, typ) {
return true
}
}
typ = typ.Underlying()
if inProgress[typ] {
// We're already looking at this type. The call that started it will take care of it.
return true
}
inProgress[typ] = true
switch typ := typ.(type) {
case *types.Signature:
return t&argPointer != 0
case *types.Map:
// Recur: map[int]int matches %d.
return t&argPointer != 0 ||
(f.matchArgTypeInternal(t, typ.Key(), arg, inProgress) && f.matchArgTypeInternal(t, typ.Elem(), arg, inProgress))
case *types.Chan:
return t&argPointer != 0
case *types.Array:
// Same as slice.
if types.Identical(typ.Elem().Underlying(), types.Typ[types.Byte]) && t&argString != 0 {
return true // %s matches []byte
}
// Recur: []int matches %d.
return t&argPointer != 0 || f.matchArgTypeInternal(t, typ.Elem().Underlying(), arg, inProgress)
case *types.Slice:
// Same as array.
if types.Identical(typ.Elem().Underlying(), types.Typ[types.Byte]) && t&argString != 0 {
return true // %s matches []byte
}
// Recur: []int matches %d. But watch out for
// type T []T
// If the element is a pointer type (type T[]*T), it's handled fine by the Pointer case below.
return t&argPointer != 0 || f.matchArgTypeInternal(t, typ.Elem(), arg, inProgress)
case *types.Pointer:
// Ugly, but dealing with an edge case: a known pointer to an invalid type,
// probably something from a failed import.
if typ.Elem().String() == "invalid type" {
if *verbose {
f.Warnf(arg.Pos(), "printf argument %v is pointer to invalid or unknown type", f.gofmt(arg))
}
return true // special case
}
// If it's actually a pointer with %p, it prints as one.
if t == argPointer {
return true
}
// If it's pointer to struct, that's equivalent in our analysis to whether we can print the struct.
if str, ok := typ.Elem().Underlying().(*types.Struct); ok {
return f.matchStructArgType(t, str, arg, inProgress)
}
// The rest can print with %p as pointers, or as integers with %x etc.
return t&(argInt|argPointer) != 0
case *types.Struct:
return f.matchStructArgType(t, typ, arg, inProgress)
case *types.Interface:
// If the static type of the argument is empty interface, there's little we can do.
// Example:
// func f(x interface{}) { fmt.Printf("%s", x) }
// Whether x is valid for %s depends on the type of the argument to f. One day
// we will be able to do better. For now, we assume that empty interface is OK
// but non-empty interfaces, with Stringer and Error handled above, are errors.
return typ.NumMethods() == 0
case *types.Basic:
switch typ.Kind() {
case types.UntypedBool,
types.Bool:
return t&argBool != 0
case types.UntypedInt,
types.Int,
types.Int8,
types.Int16,
types.Int32,
types.Int64,
types.Uint,
types.Uint8,
types.Uint16,
types.Uint32,
types.Uint64,
types.Uintptr:
return t&argInt != 0
case types.UntypedFloat,
types.Float32,
types.Float64:
return t&argFloat != 0
case types.UntypedComplex,
types.Complex64,
types.Complex128:
return t&argComplex != 0
case types.UntypedString,
types.String:
return t&argString != 0
case types.UnsafePointer:
return t&(argPointer|argInt) != 0
case types.UntypedRune:
return t&(argInt|argRune) != 0
case types.UntypedNil:
return t&argPointer != 0 // TODO?
case types.Invalid:
if *verbose {
f.Warnf(arg.Pos(), "printf argument %v has invalid or unknown type", f.gofmt(arg))
}
return true // Probably a type check problem.
}
panic("unreachable")
}
return false
}