mirror of
https://github.com/golang/go
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91 lines
2.4 KiB
Go
91 lines
2.4 KiB
Go
// Copyright 2013 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package oracle
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import (
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"code.google.com/p/go.tools/pointer"
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"code.google.com/p/go.tools/ssa"
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)
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// Callstack displays an arbitrary path from a root of the callgraph
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// to the function at the current position.
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//
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// The information may be misleading in a context-insensitive
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// analysis. e.g. the call path X->Y->Z might be infeasible if Y never
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// calls Z when it is called from X. TODO(adonovan): think about UI.
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//
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// TODO(adonovan): permit user to specify a starting point other than
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// the analysis root.
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//
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func callstack(o *oracle) (queryResult, error) {
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pkg := o.prog.Package(o.queryPkgInfo.Pkg)
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if pkg == nil {
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return nil, o.errorf(o.queryPath[0], "no SSA package")
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}
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if !ssa.HasEnclosingFunction(pkg, o.queryPath) {
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return nil, o.errorf(o.queryPath[0], "this position is not inside a function")
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}
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buildSSA(o)
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target := ssa.EnclosingFunction(pkg, o.queryPath)
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if target == nil {
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return nil, o.errorf(o.queryPath[0],
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"no SSA function built for this location (dead code?)")
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}
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// Run the pointer analysis and build the complete call graph.
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callgraph := make(pointer.CallGraph)
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o.config.Call = callgraph.AddEdge
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root := ptrAnalysis(o)
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return &callstackResult{
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target: target,
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root: root,
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callgraph: callgraph,
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}, nil
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}
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type callstackResult struct {
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target *ssa.Function
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root pointer.CallGraphNode
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callgraph pointer.CallGraph
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seen map[pointer.CallGraphNode]bool // used by display
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}
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func (r *callstackResult) search(o *oracle, cgn pointer.CallGraphNode) bool {
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if !r.seen[cgn] {
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r.seen[cgn] = true
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if cgn.Func() == r.target {
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o.printf(o, "Found a call path from root to %s", r.target)
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o.printf(r.target, "%s", r.target)
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return true
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}
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for callee, site := range r.callgraph[cgn] {
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if r.search(o, callee) {
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o.printf(site, "%s from %s", site.Description(), cgn.Func())
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return true
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}
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}
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}
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return false
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}
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func (r *callstackResult) display(o *oracle) {
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// Show only an arbitrary path from a root to the current function.
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// We use depth-first search.
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r.seen = make(map[pointer.CallGraphNode]bool)
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for toplevel := range r.callgraph[r.root] {
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if r.search(o, toplevel) {
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return
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}
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}
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o.printf(r.target, "%s is unreachable in this analysis scope", r.target)
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}
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