// runPTA runs the pointer analysis of the selected SSA value or address.
func runPTA(conf *pointer.Config, v ssa.Value, isAddr bool) (ptrs []pointerResult, err error) {
T := v.Type()
if isAddr {
conf.AddIndirectQuery(v)
T = deref(T)
} else {
conf.AddQuery(v)
}
ptares := ptrAnalysis(conf)
var ptr pointer.Pointer
if isAddr {
ptr = ptares.IndirectQueries[v]
} else {
ptr = ptares.Queries[v]
}
if ptr == (pointer.Pointer{}) {
return nil, fmt.Errorf("pointer analysis did not find expression (dead code?)")
}
pts := ptr.PointsTo()
if pointer.CanHaveDynamicTypes(T) {
// Show concrete types for interface/reflect.Value expression.
if concs := pts.DynamicTypes(); concs.Len() > 0 {
concs.Iterate(func(conc types.Type, pta interface{}) {
labels := pta.(pointer.PointsToSet).Labels()
sort.Sort(byPosAndString(labels)) // to ensure determinism
ptrs = append(ptrs, pointerResult{conc, labels})
})
}
} else {
// Show labels for other expressions.
labels := pts.Labels()
sort.Sort(byPosAndString(labels)) // to ensure determinism
ptrs = append(ptrs, pointerResult{T, labels})
}
sort.Sort(byTypeString(ptrs)) // to ensure determinism
return ptrs, nil
}
func findCallees(conf *pointer.Config, site ssa.CallInstruction) ([]*ssa.Function, error) {
// Avoid running the pointer analysis for static calls.
if callee := site.Common().StaticCallee(); callee != nil {
switch callee.String() {
case "runtime.SetFinalizer", "(reflect.Value).Call":
// The PTA treats calls to these intrinsics as dynamic.
// TODO(adonovan): avoid reliance on PTA internals.
default:
return []*ssa.Function{callee}, nil // singleton
}
}
// Dynamic call: use pointer analysis.
conf.BuildCallGraph = true
cg := ptrAnalysis(conf).CallGraph
cg.DeleteSyntheticNodes()
// Find all call edges from the site.
n := cg.Nodes[site.Parent()]
if n == nil {
return nil, fmt.Errorf("this call site is unreachable in this analysis")
}
calleesMap := make(map[*ssa.Function]bool)
for _, edge := range n.Out {
if edge.Site == site {
calleesMap[edge.Callee.Func] = true
}
}
// De-duplicate and sort.
funcs := make([]*ssa.Function, 0, len(calleesMap))
for f := range calleesMap {
funcs = append(funcs, f)
}
sort.Sort(byFuncPos(funcs))
return funcs, nil
}