mirror of
https://github.com/golang/go
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102 lines
3.0 KiB
Go
102 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/ast"
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"code.google.com/p/go.tools/go/types"
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"code.google.com/p/go.tools/pointer"
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)
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// Callees reports the possible callees of the function call site
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// identified by the specified source location.
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//
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// TODO(adonovan): if a callee is a wrapper, show the callee's callee.
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//
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func callees(o *oracle) (queryResult, error) {
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// Determine the enclosing call for the specified position.
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var call *ast.CallExpr
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for _, n := range o.queryPath {
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if call, _ = n.(*ast.CallExpr); call != nil {
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break
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}
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}
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if call == nil {
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return nil, o.errorf(o.queryPath[0], "there is no function call here")
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}
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// TODO(adonovan): issue an error if the call is "too far
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// away" from the current selection, as this most likely is
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// not what the user intended.
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// Reject type conversions.
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if o.queryPkgInfo.IsType(call.Fun) {
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return nil, o.errorf(call, "this is a type conversion, not a function call")
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}
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// Reject calls to built-ins.
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if b, ok := o.queryPkgInfo.TypeOf(call.Fun).(*types.Builtin); ok {
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return nil, o.errorf(call, "this is a call to the built-in '%s' operator", b.Name())
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}
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buildSSA(o)
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// Compute the subgraph of the callgraph for callsite(s)
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// arising from 'call'. There may be more than one if its
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// enclosing function was treated context-sensitively.
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// (Or zero if it was in dead code.)
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//
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// The presence of a key indicates this call site is
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// interesting even if the value is nil.
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querySites := make(map[pointer.CallSite][]pointer.CallGraphNode)
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o.config.CallSite = func(site pointer.CallSite) {
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if site.Pos() == call.Lparen {
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// Not a no-op! Ensures key is
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// present even if value is nil:
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querySites[site] = querySites[site]
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}
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}
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o.config.Call = func(site pointer.CallSite, caller, callee pointer.CallGraphNode) {
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if targets, ok := querySites[site]; ok {
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querySites[site] = append(targets, callee)
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}
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}
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ptrAnalysis(o)
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return &calleesResult{
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call: call,
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querySites: querySites,
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}, nil
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}
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type calleesResult struct {
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call *ast.CallExpr
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querySites map[pointer.CallSite][]pointer.CallGraphNode
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}
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func (r *calleesResult) display(o *oracle) {
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// Print the set of discovered call edges.
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if len(r.querySites) == 0 {
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// e.g. it appears within "if false {...}" or within a dead function.
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o.printf(r.call.Lparen, "this call site is unreachable in this analysis")
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}
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// TODO(adonovan): sort, to ensure test determinism.
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// TODO(adonovan): compute union of callees across all contexts.
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for site, callees := range r.querySites {
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if callees == nil {
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// dynamic call on a provably nil func/interface
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o.printf(site, "%s on nil value", site.Description())
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continue
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}
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// TODO(adonovan): sort, to ensure test determinism.
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o.printf(site, "this %s dispatches to:", site.Description())
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for _, callee := range callees {
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o.printf(callee.Func(), "\t%s", callee.Func())
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}
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}
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}
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