+++ /dev/null
-// Copyright 2013 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 callgraph
-
-import "golang.org/x/tools/go/ssa"
-
-// This file provides various utilities over call graphs, such as
-// visitation and path search.
-
-// CalleesOf returns a new set containing all direct callees of the
-// caller node.
-//
-func CalleesOf(caller *Node) map[*Node]bool {
- callees := make(map[*Node]bool)
- for _, e := range caller.Out {
- callees[e.Callee] = true
- }
- return callees
-}
-
-// GraphVisitEdges visits all the edges in graph g in depth-first order.
-// The edge function is called for each edge in postorder. If it
-// returns non-nil, visitation stops and GraphVisitEdges returns that
-// value.
-//
-func GraphVisitEdges(g *Graph, edge func(*Edge) error) error {
- seen := make(map[*Node]bool)
- var visit func(n *Node) error
- visit = func(n *Node) error {
- if !seen[n] {
- seen[n] = true
- for _, e := range n.Out {
- if err := visit(e.Callee); err != nil {
- return err
- }
- if err := edge(e); err != nil {
- return err
- }
- }
- }
- return nil
- }
- for _, n := range g.Nodes {
- if err := visit(n); err != nil {
- return err
- }
- }
- return nil
-}
-
-// PathSearch finds an arbitrary path starting at node start and
-// ending at some node for which isEnd() returns true. On success,
-// PathSearch returns the path as an ordered list of edges; on
-// failure, it returns nil.
-//
-func PathSearch(start *Node, isEnd func(*Node) bool) []*Edge {
- stack := make([]*Edge, 0, 32)
- seen := make(map[*Node]bool)
- var search func(n *Node) []*Edge
- search = func(n *Node) []*Edge {
- if !seen[n] {
- seen[n] = true
- if isEnd(n) {
- return stack
- }
- for _, e := range n.Out {
- stack = append(stack, e) // push
- if found := search(e.Callee); found != nil {
- return found
- }
- stack = stack[:len(stack)-1] // pop
- }
- }
- return nil
- }
- return search(start)
-}
-
-// DeleteSyntheticNodes removes from call graph g all nodes for
-// synthetic functions (except g.Root and package initializers),
-// preserving the topology. In effect, calls to synthetic wrappers
-// are "inlined".
-//
-func (g *Graph) DeleteSyntheticNodes() {
- // Measurements on the standard library and go.tools show that
- // resulting graph has ~15% fewer nodes and 4-8% fewer edges
- // than the input.
- //
- // Inlining a wrapper of in-degree m, out-degree n adds m*n
- // and removes m+n edges. Since most wrappers are monomorphic
- // (n=1) this results in a slight reduction. Polymorphic
- // wrappers (n>1), e.g. from embedding an interface value
- // inside a struct to satisfy some interface, cause an
- // increase in the graph, but they seem to be uncommon.
-
- // Hash all existing edges to avoid creating duplicates.
- edges := make(map[Edge]bool)
- for _, cgn := range g.Nodes {
- for _, e := range cgn.Out {
- edges[*e] = true
- }
- }
- for fn, cgn := range g.Nodes {
- if cgn == g.Root || fn.Synthetic == "" || isInit(cgn.Func) {
- continue // keep
- }
- for _, eIn := range cgn.In {
- for _, eOut := range cgn.Out {
- newEdge := Edge{eIn.Caller, eIn.Site, eOut.Callee}
- if edges[newEdge] {
- continue // don't add duplicate
- }
- AddEdge(eIn.Caller, eIn.Site, eOut.Callee)
- edges[newEdge] = true
- }
- }
- g.DeleteNode(cgn)
- }
-}
-
-func isInit(fn *ssa.Function) bool {
- return fn.Pkg != nil && fn.Pkg.Func("init") == fn
-}
-
-// DeleteNode removes node n and its edges from the graph g.
-// (NB: not efficient for batch deletion.)
-func (g *Graph) DeleteNode(n *Node) {
- n.deleteIns()
- n.deleteOuts()
- delete(g.Nodes, n.Func)
-}
-
-// deleteIns deletes all incoming edges to n.
-func (n *Node) deleteIns() {
- for _, e := range n.In {
- removeOutEdge(e)
- }
- n.In = nil
-}
-
-// deleteOuts deletes all outgoing edges from n.
-func (n *Node) deleteOuts() {
- for _, e := range n.Out {
- removeInEdge(e)
- }
- n.Out = nil
-}
-
-// removeOutEdge removes edge.Caller's outgoing edge 'edge'.
-func removeOutEdge(edge *Edge) {
- caller := edge.Caller
- n := len(caller.Out)
- for i, e := range caller.Out {
- if e == edge {
- // Replace it with the final element and shrink the slice.
- caller.Out[i] = caller.Out[n-1]
- caller.Out[n-1] = nil // aid GC
- caller.Out = caller.Out[:n-1]
- return
- }
- }
- panic("edge not found: " + edge.String())
-}
-
-// removeInEdge removes edge.Callee's incoming edge 'edge'.
-func removeInEdge(edge *Edge) {
- caller := edge.Callee
- n := len(caller.In)
- for i, e := range caller.In {
- if e == edge {
- // Replace it with the final element and shrink the slice.
- caller.In[i] = caller.In[n-1]
- caller.In[n-1] = nil // aid GC
- caller.In = caller.In[:n-1]
- return
- }
- }
- panic("edge not found: " + edge.String())
-}
projects / dotfiles / .git / blobdiff