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// Copyright 2021 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package vulncheck
import (
"golang.org/x/tools/go/callgraph"
"golang.org/x/tools/go/ssa"
)
// forwardSlice computes the transitive closure of functions forward reachable
// via calls in cg or referred to in an instruction starting from `sources`.
func forwardSlice(sources map[*ssa.Function]bool, cg *callgraph.Graph) map[*ssa.Function]bool {
seen := make(map[*ssa.Function]bool)
var visit func(f *ssa.Function)
visit = func(f *ssa.Function) {
if seen[f] {
return
}
seen[f] = true
if n := cg.Nodes[f]; n != nil {
for _, e := range n.Out {
if e.Site != nil {
visit(e.Callee.Func)
}
}
}
var buf [10]*ssa.Value // avoid alloc in common case
for _, b := range f.Blocks {
for _, instr := range b.Instrs {
for _, op := range instr.Operands(buf[:0]) {
if fn, ok := (*op).(*ssa.Function); ok {
visit(fn)
}
}
}
}
}
for source := range sources {
visit(source)
}
return seen
}
// pruneSet removes functions in `set` that are in `toPrune`.
func pruneSet(set, toPrune map[*ssa.Function]bool) {
for f := range set {
if !toPrune[f] {
delete(set, f)
}
}
}
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