mirror of
https://github.com/golang/go
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119 lines
3.6 KiB
Go
119 lines
3.6 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 pointer
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import (
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"fmt"
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"go/token"
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"code.google.com/p/go.tools/ssa"
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)
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// TODO(adonovan): move the CallGraph, CallGraphNode, CallSite types
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// into a separate package 'callgraph', and make them pure interfaces
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// capable of supporting several implementations (context-sensitive
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// and insensitive PTA, RTA, etc).
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// ---------- CallGraphNode ----------
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// A CallGraphNode is a context-sensitive representation of a node in
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// the callgraph. In other words, there may be multiple nodes
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// representing a single *Function, depending on the contexts in which
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// it is called. The identity of the node is therefore important.
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//
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type CallGraphNode interface {
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Func() *ssa.Function // the function this node represents
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String() string // diagnostic description of this callgraph node
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}
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type cgnode struct {
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fn *ssa.Function
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obj nodeid // start of this contour's object block
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}
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func (n *cgnode) Func() *ssa.Function {
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return n.fn
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}
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func (n *cgnode) String() string {
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return fmt.Sprintf("cg%d:%s", n.obj, n.fn)
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}
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// ---------- CallSite ----------
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// A CallSite is a context-sensitive representation of a function call
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// site in the program.
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//
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type CallSite interface {
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Caller() CallGraphNode // the enclosing context of this call
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Pos() token.Pos // source position; token.NoPos for synthetic calls
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Description() string // UI description of call kind; see (*ssa.CallCommon).Description
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String() string // diagnostic description of this callsite
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}
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// A callsite represents a single function or method callsite within a
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// function. callsites never represent calls to built-ins; they are
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// handled as intrinsics.
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//
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type callsite struct {
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caller *cgnode // the origin of the call
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targets nodeid // pts(targets) contains identities of all called functions.
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instr ssa.CallInstruction // optional call instruction; provides IsInvoke, position, etc.
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pos token.Pos // position, if instr == nil, i.e. synthetic callsites.
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}
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// Caller returns the node in the callgraph from which this call originated.
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func (c *callsite) Caller() CallGraphNode {
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return c.caller
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}
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// Description returns a description of this kind of call, in the
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// manner of ssa.CallCommon.Description().
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//
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func (c *callsite) Description() string {
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if c.instr != nil {
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return c.instr.Common().Description()
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}
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return "synthetic function call"
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}
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// Pos returns the source position of this callsite, or token.NoPos if implicit.
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func (c *callsite) Pos() token.Pos {
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if c.instr != nil {
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return c.instr.Pos()
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}
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return c.pos
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}
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func (c *callsite) String() string {
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// TODO(adonovan): provide more info, e.g. target of static
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// call, arguments, location.
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return c.Description()
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}
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// ---------- CallGraph ----------
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// CallGraph is a forward directed graph of functions labelled by an
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// arbitrary site within the caller.
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//
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// CallGraph.AddEdge may be used as the Context.Call callback for
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// clients that wish to construct a call graph.
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//
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// TODO(adonovan): this is just a starting point. Add options to
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// control whether we record no callsite, an arbitrary callsite, or
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// all callsites for a given graph edge. Also, this could live in
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// another package since it's just a client utility.
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//
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type CallGraph map[CallGraphNode]map[CallGraphNode]CallSite
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func (cg CallGraph) AddEdge(site CallSite, caller, callee CallGraphNode) {
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callees := cg[caller]
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if callees == nil {
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callees = make(map[CallGraphNode]CallSite)
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cg[caller] = callees
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}
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callees[callee] = site // save an arbitrary site
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}
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