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go/oracle/callgraph.go
Alan Donovan d2cdbefbfc go.tools/oracle: add option to output results in JSON syntax.
See json.go for interface specification.

Example usage:
% oracle -format=json -mode=callgraph code.google.com/p/go.tools/cmd/oracle

+ Tests, based on (small) golden files.

Overview:
  Each <query>Result structure has been "lowered" so that all
  but the most trivial logic in each display() function has
  been moved to the main query.

  Each one now has a toJSON method that populates a json.Result
  struct.  Though the <query>Result structs are similar to the
  correponding JSON protocol, they're not close enough to be
  used directly; for example, the former contain richer
  semantic entities (token.Pos, ast.Expr, ssa.Value,
  pointer.Pointer, etc) whereas JSON contains only their
  printed forms using Go basic types.

  The choices of what levels of abstractions the two sets of
  structs should have is somewhat arbitrary.  We may want
  richer information in the JSON output in future.

Details:
- oracle.Main has been split into oracle.Query() and the
  printing of the oracle.Result.
- the display() method no longer needs an *oracle param, only
  a print function.
- callees: sort the result for determinism.
- callees: compute the union across all contexts.
- callers: sort the results for determinism.
- describe(package): fixed a bug in the predicate for method
  accessibility: an unexported method defined in pkg A may
  belong to a type defined in package B (via
  embedding/promotion) and may thus be accessible to A.  New
  accessibleMethods() utility fixes this.
- describe(type): filter methods by accessibility.
- added tests of 'callgraph'.
- pointer: eliminated the 'caller CallGraphNode' parameter from
  pointer.Context.Call callback since it was redundant w.r.t
  site.Caller().
- added warning if CGO_ENABLED is unset.

R=crawshaw
CC=golang-dev
https://golang.org/cl/13270045
2013-09-03 15:29:02 -04:00

103 lines
2.8 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 (
"go/token"
"strings"
"code.google.com/p/go.tools/oracle/json"
"code.google.com/p/go.tools/pointer"
)
// callgraph displays the entire callgraph of the current program.
//
// Nodes may be seem to appear multiple times due to (limited)
// context sensitivity.
//
// TODO(adonovan): add options for restricting the display to a region
// of interest: function, package, subgraph, dirtree, goroutine, etc.
//
// TODO(adonovan): add an option to project away context sensitivity.
// The callgraph API should provide this feature.
//
// TODO(adonovan): elide nodes for synthetic functions?
//
func callgraph(o *oracle) (queryResult, error) {
buildSSA(o)
// Run the pointer analysis and build the complete callgraph.
callgraph := make(pointer.CallGraph)
o.config.Call = callgraph.AddEdge
root := ptrAnalysis(o)
// Assign (preorder) numbers to all the callgraph nodes.
// TODO(adonovan): the callgraph API should do this for us.
numbering := make(map[pointer.CallGraphNode]int)
var number func(cgn pointer.CallGraphNode)
number = func(cgn pointer.CallGraphNode) {
if _, ok := numbering[cgn]; !ok {
numbering[cgn] = len(numbering)
for callee := range callgraph[cgn] {
number(callee)
}
}
}
number(root)
return &callgraphResult{
root: root,
callgraph: callgraph,
numbering: numbering,
}, nil
}
type callgraphResult struct {
root pointer.CallGraphNode
callgraph pointer.CallGraph
numbering map[pointer.CallGraphNode]int
}
func (r *callgraphResult) display(printf printfFunc) {
printf(nil, `
Below is a call graph of the entire program.
The numbered nodes form a spanning tree.
Non-numbered nodes indicate back- or cross-edges to the node whose
number follows in parentheses.
Some nodes may appear multiple times due to context-sensitive
treatment of some calls.
`)
seen := make(map[pointer.CallGraphNode]bool)
var print func(cgn pointer.CallGraphNode, indent int)
print = func(cgn pointer.CallGraphNode, indent int) {
n := r.numbering[cgn]
if !seen[cgn] {
seen[cgn] = true
printf(cgn.Func(), "%d\t%s%s", n, strings.Repeat(" ", indent), cgn.Func())
for callee := range r.callgraph[cgn] {
print(callee, indent+1)
}
} else {
printf(cgn.Func(), "\t%s%s (%d)", strings.Repeat(" ", indent), cgn.Func(), n)
}
}
print(r.root, 0)
}
func (r *callgraphResult) toJSON(res *json.Result, fset *token.FileSet) {
cg := make([]json.CallGraph, len(r.numbering))
for n, i := range r.numbering {
j := &cg[i]
fn := n.Func()
j.Name = fn.String()
j.Pos = fn.Prog.Fset.Position(fn.Pos()).String()
for callee := range r.callgraph[n] {
j.Children = append(j.Children, r.numbering[callee])
}
}
res.Callgraph = cg
}