// valueOffsetNode ascertains the node for tuple/struct value v,
// then returns the node for its subfield #index.
//
func (a *analysis) valueOffsetNode(v ssa.Value, index int) nodeid {
id := a.valueNode(v)
if id == 0 {
panic(fmt.Sprintf("cannot offset within n0: %s = %s", v.Name(), v))
}
return id + nodeid(a.offsetOf(v.Type(), index))
}
// setValueNode associates node id with the value v.
// TODO(adonovan): disambiguate v by its CallGraphNode, if it's a local.
func (a *analysis) setValueNode(v ssa.Value, id nodeid) {
a.valNode[v] = id
if a.log != nil {
fmt.Fprintf(a.log, "\tval[%s] = n%d (%T)\n", v.Name(), id, v)
}
// Record the (v, id) relation if the client has queried v.
if indirect, ok := a.config.Queries[v]; ok {
if indirect {
tmp := a.addNodes(v.Type(), "query.indirect")
a.load(tmp, id, a.sizeof(v.Type()))
id = tmp
}
a.queries[v] = append(a.queries[v], ptr{a, id})
}
}
func (fr *frame) get(key ssa.Value) value {
switch key := key.(type) {
case nil:
// Hack; simplifies handling of optional attributes
// such as ssa.Slice.{Low,High}.
return nil
case *ssa.Function, *ssa.Builtin:
return key
case *ssa.Const:
return constValue(key)
case *ssa.Global:
if r, ok := fr.i.globals[key]; ok {
return r
}
}
if r, ok := fr.env[key]; ok {
return r
}
panic(fmt.Sprintf("get: no value for %T: %v", key, key.Name()))
}
// setValueNode associates node id with the value v.
// cgn identifies the context iff v is a local variable.
//
func (a *analysis) setValueNode(v ssa.Value, id nodeid, cgn *cgnode) {
if cgn != nil {
a.localval[v] = id
} else {
a.globalval[v] = id
}
if a.log != nil {
fmt.Fprintf(a.log, "\tval[%s] = n%d (%T)\n", v.Name(), id, v)
}
// Record the (v, id) relation if the client has queried v.
if indirect, ok := a.config.Queries[v]; ok {
if indirect {
tmp := a.addNodes(v.Type(), "query.indirect")
a.genLoad(cgn, tmp, v, 0, a.sizeof(v.Type()))
id = tmp
}
a.result.Queries[v] = append(a.result.Queries[v], ptr{a, cgn, id})
}
}
// objectNode returns the object to which v points, if known.
// In other words, if the points-to set of v is a singleton, it
// returns the sole label, zero otherwise.
//
// We exploit this information to make the generated constraints less
// dynamic. For example, a complex load constraint can be replaced by
// a simple copy constraint when the sole destination is known a priori.
//
// Some SSA instructions always have singletons points-to sets:
// Alloc, Function, Global, MakeChan, MakeClosure, MakeInterface, MakeMap, MakeSlice.
// Others may be singletons depending on their operands:
// Capture, Const, Convert, FieldAddr, IndexAddr, Slice.
//
// Idempotent. Objects are created as needed, possibly via recursion
// down the SSA value graph, e.g IndexAddr(FieldAddr(Alloc))).
//
func (a *analysis) objectNode(cgn *cgnode, v ssa.Value) nodeid {
if cgn == nil {
// Global object.
obj, ok := a.globalobj[v]
if !ok {
switch v := v.(type) {
case *ssa.Global:
obj = a.nextNode()
a.addNodes(mustDeref(v.Type()), "global")
a.endObject(obj, nil, v)
case *ssa.Function:
obj = a.makeFunctionObject(v, nil)
case *ssa.Const:
if t, ok := v.Type().Underlying().(*types.Slice); ok && !v.IsNil() {
// Non-nil []byte or []rune constant.
obj = a.nextNode()
a.addNodes(sliceToArray(t), "array in slice constant")
a.endObject(obj, nil, v)
}
case *ssa.Capture:
// For now, Captures have the same cardinality as globals.
// TODO(adonovan): treat captures context-sensitively.
}
if a.log != nil {
fmt.Fprintf(a.log, "\tglobalobj[%s] = n%d\n", v, obj)
}
a.globalobj[v] = obj
}
return obj
}
// Local object.
obj, ok := a.localobj[v]
if !ok {
switch v := v.(type) {
case *ssa.Alloc:
obj = a.nextNode()
a.addNodes(mustDeref(v.Type()), "alloc")
a.endObject(obj, cgn, v)
case *ssa.MakeSlice:
obj = a.nextNode()
a.addNodes(sliceToArray(v.Type()), "makeslice")
a.endObject(obj, cgn, v)
case *ssa.MakeChan:
obj = a.nextNode()
a.addNodes(v.Type().Underlying().(*types.Chan).Elem(), "makechan")
a.endObject(obj, cgn, v)
case *ssa.MakeMap:
obj = a.nextNode()
tmap := v.Type().Underlying().(*types.Map)
a.addNodes(tmap.Key(), "makemap.key")
a.addNodes(tmap.Elem(), "makemap.value")
a.endObject(obj, cgn, v)
case *ssa.MakeInterface:
tConc := v.X.Type()
obj = a.makeTagged(tConc, cgn, v)
// Copy the value into it, if nontrivial.
if x := a.valueNode(v.X); x != 0 {
a.copy(obj+1, x, a.sizeof(tConc))
}
case *ssa.FieldAddr:
if xobj := a.objectNode(cgn, v.X); xobj != 0 {
obj = xobj + nodeid(a.offsetOf(mustDeref(v.X.Type()), v.Field))
}
case *ssa.IndexAddr:
if xobj := a.objectNode(cgn, v.X); xobj != 0 {
obj = xobj + 1
}
case *ssa.Slice:
obj = a.objectNode(cgn, v.X)
case *ssa.Convert:
// TODO(adonovan): opt: handle these cases too:
// - unsafe.Pointer->*T conversion acts like Alloc
// - string->[]byte/[]rune conversion acts like MakeSlice
}
if a.log != nil {
fmt.Fprintf(a.log, "\tlocalobj[%s] = n%d\n", v.Name(), obj)
}
a.localobj[v] = obj
}
return obj
}