116 lines
3.0 KiB
Go
116 lines
3.0 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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"go/token"
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"code.google.com/p/go.tools/oracle/json"
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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, qpos *QueryPos) (queryResult, error) {
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pkg := o.prog.Package(qpos.info.Pkg)
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if pkg == nil {
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return nil, o.errorf(qpos.path[0], "no SSA package")
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}
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if !ssa.HasEnclosingFunction(pkg, qpos.path) {
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return nil, o.errorf(qpos.path[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, qpos.path)
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if target == nil {
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return nil, o.errorf(qpos.path[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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seen := make(map[pointer.CallGraphNode]bool)
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var callstack []pointer.CallSite
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// Use depth-first search to find an arbitrary path from a
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// root to the target function.
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var search func(cgn pointer.CallGraphNode) bool
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search = func(cgn pointer.CallGraphNode) bool {
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if !seen[cgn] {
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seen[cgn] = true
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if cgn.Func() == target {
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return true
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}
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for callee, site := range callgraph[cgn] {
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if search(callee) {
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callstack = append(callstack, site)
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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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for toplevel := range callgraph[root] {
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if search(toplevel) {
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break
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}
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}
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return &callstackResult{
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qpos: qpos,
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target: target,
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callstack: callstack,
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}, nil
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}
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type callstackResult struct {
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qpos *QueryPos
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target *ssa.Function
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callstack []pointer.CallSite
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}
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func (r *callstackResult) display(printf printfFunc) {
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if r.callstack != nil {
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printf(r.qpos, "Found a call path from root to %s", r.target)
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printf(r.target, "%s", r.target)
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for _, site := range r.callstack {
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printf(site, "%s from %s", site.Description(), site.Caller().Func())
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}
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} else {
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printf(r.target, "%s is unreachable in this analysis scope", r.target)
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}
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}
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func (r *callstackResult) toJSON(res *json.Result, fset *token.FileSet) {
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var callers []json.Caller
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for _, site := range r.callstack {
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callers = append(callers, json.Caller{
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Pos: fset.Position(site.Pos()).String(),
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Caller: site.Caller().Func().String(),
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Desc: site.Description(),
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})
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}
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res.Callstack = &json.CallStack{
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Pos: fset.Position(r.target.Pos()).String(),
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Target: r.target.String(),
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Callers: callers,
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}
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}
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