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go.tools/oracle: consider calls to close a peer operation. 

This makes it possible to find corresponding closes to receives and sends.

LGTM=adonovan
R=adonovan
CC=golang-codereviews
https://golang.org/cl/155260043
This commit is contained in:
Daniel Morsing 2014-10-12 15:08:28 +01:00
parent cced8d21dd
commit 70f0e2472d
5 changed files with 94 additions and 21 deletions
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2
oracle/TODO
View File

@ -70,7 +70,7 @@ describe
peers
Permit querying from a makechan, close(), for...range, or reflective op.
Permit querying from a makechan, for...range, or reflective op.
Report aliasing reflect.{Send,Recv,Close} and close() operations.

63
oracle/peers.go
View File

@ -22,12 +22,10 @@ import (
// TODO(adonovan): support reflect.{Select,Recv,Send,Close}.
// TODO(adonovan): permit the user to query based on a MakeChan (not send/recv),
// or the implicit receive in "for v := range ch".
// TODO(adonovan): support "close" as a channel op.
//
func peers(o *Oracle, qpos *QueryPos) (queryResult, error) {
arrowPos := findArrow(qpos)
if arrowPos == token.NoPos {
return nil, fmt.Errorf("there is no send/receive here")
opPos := findOp(qpos)
if opPos == token.NoPos {
return nil, fmt.Errorf("there is no channel operation here")
}
buildSSA(o)
@ -35,15 +33,15 @@ func peers(o *Oracle, qpos *QueryPos) (queryResult, error) {
var queryOp chanOp // the originating send or receive operation
var ops []chanOp // all sends/receives of opposite direction
// Look at all send/receive instructions in the whole ssa.Program.
// Build a list of those of same type to query.
// Look at all channel operations in the whole ssa.Program.
// Build a list of those of same type as the query.
allFuncs := ssautil.AllFunctions(o.prog)
for fn := range allFuncs {
for _, b := range fn.Blocks {
for _, instr := range b.Instrs {
for _, op := range chanOps(instr) {
ops = append(ops, op)
if op.pos == arrowPos {
if op.pos == opPos {
queryOp = op // we found the query op
}
}
@ -84,33 +82,40 @@ func peers(o *Oracle, qpos *QueryPos) (queryResult, error) {
}
sort.Sort(byPos(makes))
// Ascertain which send/receive operations can alias the same make(chan) labels.
var sends, receives []token.Pos
// Ascertain which channel operations can alias the same make(chan) labels.
var sends, receives, closes []token.Pos
for _, op := range ops {
if ptr, ok := ptares.Queries[op.ch]; ok && ptr.MayAlias(queryChanPtr) {
if op.dir == types.SendOnly {
switch op.dir {
case types.SendOnly:
sends = append(sends, op.pos)
} else {
case types.RecvOnly:
receives = append(receives, op.pos)
case types.SendRecv:
closes = append(closes, op.pos)
}
}
}
sort.Sort(byPos(sends))
sort.Sort(byPos(receives))
sort.Sort(byPos(closes))
return &peersResult{
queryPos: arrowPos,
queryPos: opPos,
queryType: queryType,
makes: makes,
sends: sends,
receives: receives,
closes: closes,
}, nil
}
// findArrow returns the position of the enclosing send/receive op
// (<-) for the query position, or token.NoPos if not found.
// findOp returns the position of the enclosing send/receive/close op.
// For send and receive operations, this is the position of the <- token;
// for close operations, it's the Lparen of the function call.
//
func findArrow(qpos *QueryPos) token.Pos {
// TODO(adonovan): handle implicit receive operations from 'for...range chan' statements.
func findOp(qpos *QueryPos) token.Pos {
for _, n := range qpos.path {
switch n := n.(type) {
case *ast.UnaryExpr:
@ -119,6 +124,13 @@ func findArrow(qpos *QueryPos) token.Pos {
}
case *ast.SendStmt:
return n.Arrow
case *ast.CallExpr:
// close function call can only exist as a direct identifier
if close, ok := unparen(n.Fun).(*ast.Ident); ok {
if b, ok := qpos.info.Info.Uses[close].(*types.Builtin); ok && b.Name() == "close" {
return n.Lparen
}
}
}
}
return token.NoPos
@ -127,7 +139,7 @@ func findArrow(qpos *QueryPos) token.Pos {
// chanOp abstracts an ssa.Send, ssa.Unop(ARROW), or a SelectState.
type chanOp struct {
ch ssa.Value
dir types.ChanDir // SendOnly or RecvOnly
dir types.ChanDir // SendOnly=send, RecvOnly=recv, SendRecv=close
pos token.Pos
}
@ -146,14 +158,19 @@ func chanOps(instr ssa.Instruction) []chanOp {
for _, st := range instr.States {
ops = append(ops, chanOp{st.Chan, st.Dir, st.Pos})
}
case ssa.CallInstruction:
cc := instr.Common()
if b, ok := cc.Value.(*ssa.Builtin); ok && b.Name() == "close" {
ops = append(ops, chanOp{cc.Args[0], types.SendRecv, cc.Pos()})
}
}
return ops
}
type peersResult struct {
queryPos token.Pos // of queried '<-' token
queryType types.Type // type of queried channel
makes, sends, receives []token.Pos // positions of aliased makechan/send/receive instrs
queryPos token.Pos // of queried channel op
queryType types.Type // type of queried channel
makes, sends, receives, closes []token.Pos // positions of aliased makechan/send/receive/close instrs
}
func (r *peersResult) display(printf printfFunc) {
@ -171,6 +188,9 @@ func (r *peersResult) display(printf printfFunc) {
for _, receive := range r.receives {
printf(receive, "\treceived from, here")
}
for _, clos := range r.closes {
printf(clos, "\tclosed, here")
}
}
func (r *peersResult) toSerial(res *serial.Result, fset *token.FileSet) {
@ -187,6 +207,9 @@ func (r *peersResult) toSerial(res *serial.Result, fset *token.FileSet) {
for _, receive := range r.receives {
peers.Receives = append(peers.Receives, fset.Position(receive).String())
}
for _, clos := range r.closes {
peers.Closes = append(peers.Closes, fset.Position(clos).String())
}
res.Peers = peers
}

1
oracle/serial/serial.go
View File

@ -22,6 +22,7 @@ type Peers struct {
Allocs []string `json:"allocs,omitempty"` // locations of aliased make(chan) ops
Sends []string `json:"sends,omitempty"` // locations of aliased ch<-x ops
Receives []string `json:"receives,omitempty"` // locations of aliased <-ch ops
Closes []string `json:"closes,omitempty"` // locations of aliased close(ch) ops
}
// A Referrers is the result of a 'referrers' query.

12
oracle/testdata/src/main/peers.go vendored
View File

@ -37,4 +37,16 @@ func main() {
for _ = range chA {
}
close(chA) // @peers peer-close-chA "chA"
chC := make(chan *int)
(close)(chC) // @peers peer-close-chC "chC"
close := func(ch chan *int) chan *int {
return ch
}
close(chC) <- &b // @peers peer-send-chC "chC"
<-close(chC) // @peers peer-recv-chC "chC"
}

37
oracle/testdata/src/main/peers.golden vendored
View File

@ -22,6 +22,7 @@ This channel of type chan *int may be:
received from, here
received from, here
received from, here
closed, here
-------- @pointsto pointsto-rA --------
this *int may point to these objects:
@ -50,6 +51,7 @@ This channel of type chan *int may be:
received from, here
received from, here
received from, here
closed, here
-------- @peers peer-send-chA' --------
This channel of type chan *int may be:
@ -60,4 +62,39 @@ This channel of type chan *int may be:
received from, here
received from, here
received from, here
closed, here
-------- @peers peer-close-chA --------
This channel of type chan *int may be:
allocated here
allocated here
sent to, here
sent to, here
received from, here
received from, here
received from, here
received from, here
received from, here
closed, here
-------- @peers peer-close-chC --------
This channel of type chan *int may be:
allocated here
sent to, here
received from, here
closed, here
-------- @peers peer-send-chC --------
This channel of type chan *int may be:
allocated here
sent to, here
received from, here
closed, here
-------- @peers peer-recv-chC --------
This channel of type chan *int may be:
allocated here
sent to, here
received from, here
closed, here