127 lines
3.2 KiB
Go
127 lines
3.2 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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"fmt"
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"go/token"
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"golang.org/x/tools/go/callgraph"
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"golang.org/x/tools/go/loader"
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"golang.org/x/tools/go/ssa"
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"golang.org/x/tools/go/ssa/ssautil"
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"golang.org/x/tools/oracle/serial"
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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(q *Query) error {
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fset := token.NewFileSet()
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lconf := loader.Config{Fset: fset, Build: q.Build}
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if err := setPTAScope(&lconf, q.Scope); err != nil {
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return err
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}
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// Load/parse/type-check the program.
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lprog, err := lconf.Load()
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if err != nil {
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return err
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}
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qpos, err := parseQueryPos(lprog, q.Pos, false)
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if err != nil {
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return err
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}
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prog := ssautil.CreateProgram(lprog, 0)
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ptaConfig, err := setupPTA(prog, lprog, q.PTALog, q.Reflection)
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if err != nil {
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return err
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}
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pkg := prog.Package(qpos.info.Pkg)
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if pkg == nil {
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return fmt.Errorf("no SSA package")
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}
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if !ssa.HasEnclosingFunction(pkg, qpos.path) {
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return fmt.Errorf("this position is not inside a function")
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}
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// Defer SSA construction till after errors are reported.
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prog.BuildAll()
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target := ssa.EnclosingFunction(pkg, qpos.path)
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if target == nil {
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return fmt.Errorf("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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ptaConfig.BuildCallGraph = true
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cg := ptrAnalysis(ptaConfig).CallGraph
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cg.DeleteSyntheticNodes()
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// Search for an arbitrary path from a root to the target function.
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isEnd := func(n *callgraph.Node) bool { return n.Func == target }
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callpath := callgraph.PathSearch(cg.Root, isEnd)
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if callpath != nil {
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callpath = callpath[1:] // remove synthetic edge from <root>
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}
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q.Fset = fset
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q.result = &callstackResult{
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qpos: qpos,
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target: target,
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callpath: callpath,
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}
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return 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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callpath []*callgraph.Edge
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}
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func (r *callstackResult) display(printf printfFunc) {
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if r.callpath != 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 i := len(r.callpath) - 1; i >= 0; i-- {
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edge := r.callpath[i]
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printf(edge, "%s from %s", edge.Description(), edge.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) toSerial(res *serial.Result, fset *token.FileSet) {
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var callers []serial.Caller
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for i := len(r.callpath) - 1; i >= 0; i-- { // (innermost first)
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edge := r.callpath[i]
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callers = append(callers, serial.Caller{
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Pos: fset.Position(edge.Pos()).String(),
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Caller: edge.Caller.Func.String(),
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Desc: edge.Description(),
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})
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}
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res.Callstack = &serial.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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