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go/oracle/callers.go
Alan Donovan 829d52f2e8 go.tools/go/callgraph: simplifications to API.
1) We remove context sensitivity from API.  The pointer analysis is
   not sufficiently context-sensitive for the context information to
   be worth exposing.  (The actual analysis precision still benefits
   from being context-sensitive, though.)  Since all clients would
   discard the context info, we now do that for them.
2) Make the graph doubly-linked.  Edges are now shared by the Nodes
   at both ends of the edge so it's possible to navigate more easily
   (e.g. to the callers).
3) Graph and Node are now concrete, not interfaces.

Less code in every file!

LGTM=crawshaw
R=crawshaw
CC=golang-codereviews
https://golang.org/cl/66460043
2014-02-20 11:57:48 -05:00

89 lines
2.3 KiB
Go

// 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 oracle
import (
"fmt"
"go/token"
"code.google.com/p/go.tools/go/callgraph"
"code.google.com/p/go.tools/go/ssa"
"code.google.com/p/go.tools/oracle/serial"
)
// Callers reports the possible callers of the function
// immediately enclosing the specified source location.
//
// TODO(adonovan): if a caller is a wrapper, show the caller's caller.
//
func callers(o *Oracle, qpos *QueryPos) (queryResult, error) {
pkg := o.prog.Package(qpos.info.Pkg)
if pkg == nil {
return nil, fmt.Errorf("no SSA package")
}
if !ssa.HasEnclosingFunction(pkg, qpos.path) {
return nil, fmt.Errorf("this position is not inside a function")
}
buildSSA(o)
target := ssa.EnclosingFunction(pkg, qpos.path)
if target == nil {
return nil, fmt.Errorf("no SSA function built for this location (dead code?)")
}
// Run the pointer analysis, recording each
// call found to originate from target.
o.ptaConfig.BuildCallGraph = true
cg := ptrAnalysis(o).CallGraph
edges := cg.CreateNode(target).In
// TODO(adonovan): sort + dedup calls to ensure test determinism.
return &callersResult{
target: target,
callgraph: cg,
edges: edges,
}, nil
}
type callersResult struct {
target *ssa.Function
callgraph *callgraph.Graph
edges []*callgraph.Edge
}
func (r *callersResult) display(printf printfFunc) {
root := r.callgraph.Root
if r.edges == nil {
printf(r.target, "%s is not reachable in this program.", r.target)
} else {
printf(r.target, "%s is called from these %d sites:", r.target, len(r.edges))
for _, edge := range r.edges {
if edge.Caller == root {
printf(r.target, "the root of the call graph")
} else {
printf(edge.Site, "\t%s from %s", edge.Site.Common().Description(), edge.Caller.Func)
}
}
}
}
func (r *callersResult) toSerial(res *serial.Result, fset *token.FileSet) {
root := r.callgraph.Root
var callers []serial.Caller
for _, edge := range r.edges {
var c serial.Caller
c.Caller = edge.Caller.Func.String()
if edge.Caller == root {
c.Desc = "synthetic call"
} else {
c.Pos = fset.Position(edge.Site.Pos()).String()
c.Desc = edge.Site.Common().Description()
}
callers = append(callers, c)
}
res.Callers = callers
}