func prepare() {
// group objects by type
fmt.Println("Grouping by type...")
byType = make([]bucket, len(d.FTList))
for i := 0; i < d.NumObjects(); i++ {
x := read.ObjId(i)
tid := d.Ft(x).Id
b := byType[tid]
b.bytes += d.Size(x)
b.objects = append(b.objects, x)
byType[tid] = b
}
// compute referrers
fmt.Println("Computing referrers...")
ref1 = make([]read.ObjId, d.NumObjects())
for i := 0; i < d.NumObjects(); i++ {
ref1[i] = read.ObjNil
}
ref2 = map[read.ObjId][]read.ObjId{}
for i := 0; i < d.NumObjects(); i++ {
x := read.ObjId(i)
//fmt.Printf("object %d %x %d %s %s\n", i, d.Addr(x), d.Size(x), d.Ft(x).GCSig, d.Ft(x).Name)
//printbytes(d.Contents(x))
for _, e := range d.Edges(x) {
r := ref1[e.To]
if r == read.ObjNil {
ref1[e.To] = x
} else if x != r {
s := ref2[e.To]
if len(s) == 0 || x != s[len(s)-1] {
ref2[e.To] = append(s, x)
}
}
}
}
dom()
}
func objHandler(w http.ResponseWriter, r *http.Request) {
q := r.URL.Query()
v := q["id"]
if len(v) != 1 {
http.Error(w, "id parameter missing", 405)
return
}
id, err := strconv.ParseUint(v[0], 10, 64)
if err != nil {
http.Error(w, err.Error(), 405)
return
}
if int(id) >= d.NumObjects() {
http.Error(w, "object not found", 405)
return
}
x := read.ObjId(id)
fld := getFields(d.Contents(x), d.Ft(x).Fields, d.Edges(x))
if len(fld) > maxFields {
msg := fmt.Sprintf("<font color=Red>elided for display: %d fields</font>", len(fld)-(maxFields-1))
fld = fld[:maxFields-1]
fld = append(fld, Field{msg, "", ""})
}
ref := getReferrers(x)
if len(ref) > maxFields {
msg := fmt.Sprintf("<font color=Red>elided for display: %d referrers</font>", len(ref)-(maxFields-1))
ref = ref[:maxFields-1]
ref = append(ref, msg)
}
info := objInfo{
d.Addr(x),
typeLink(d.Ft(x)),
d.Size(x),
fld,
ref,
domsize[x],
}
if err := objTemplate.Execute(w, info); err != nil {
log.Print(err)
}
}
func dom() {
fmt.Println("Computing dominators...")
n := d.NumObjects()
// make list of roots
// TODO: have loader compute this?
roots := map[read.ObjId]struct{}{}
for _, s := range []*read.Data{d.Data, d.Bss} {
for _, e := range s.Edges {
roots[e.To] = struct{}{}
}
}
for _, f := range d.Frames {
for _, e := range f.Edges {
roots[e.To] = struct{}{}
}
}
for _, x := range d.Otherroots {
for _, e := range x.Edges {
roots[e.To] = struct{}{}
}
}
// compute postorder traversal
// object states:
// 0 - not seen yet
// 1 - seen, added to queue, not yet expanded children
// 2 - seen, already expanded children
// 3 - added to postorder
postorder := make([]read.ObjId, 0, n)
postnum := make([]int, n+1)
state := make([]byte, n)
var q []read.ObjId // stack of work to do, holds state 1 and 2 objects
for x := range roots {
if state[x] != 0 {
if state[x] != 3 {
log.Fatal("bad state found")
}
continue
}
state[x] = 1
q = q[:0]
q = append(q, x)
for len(q) > 0 {
y := q[len(q)-1]
if state[y] == 2 {
state[y] = 3
q = q[:len(q)-1]
postnum[y] = len(postorder)
postorder = append(postorder, y)
} else {
if state[y] != 1 {
log.Fatal("bad state")
}
state[y] = 2
for _, e := range d.Edges(y) {
z := e.To
if state[z] == 0 {
state[z] = 1
q = append(q, z)
}
}
}
}
}
postnum[n] = n // virtual start node
// compute immediate dominators
// http://www.hipersoft.rice.edu/grads/publications/dom14.pdf
idom := make([]read.ObjId, n+1)
for i := 0; i < n; i++ {
idom[i] = read.ObjNil
}
idom[n] = read.ObjId(n)
for r := range roots {
idom[r] = read.ObjId(n)
}
var redges []read.ObjId
change := true
for change {
change = false
for i := len(postorder) - 1; i >= 0; i-- {
x := postorder[i]
// get list of incoming edges
redges = redges[:0]
if ref1[x] != read.ObjNil {
redges = append(redges, ref1[x])
redges = append(redges, ref2[x]...)
}
a := read.ObjNil
for _, b := range redges {
if idom[b] == read.ObjNil {
continue
}
if a == read.ObjNil {
a = b
continue
}
for a != b {
if postnum[a] < postnum[b] {
a = idom[a]
} else {
b = idom[b]
}
}
}
if _, ok := roots[x]; ok {
a = read.ObjId(n)
}
if a != idom[x] {
idom[x] = a
change = true
}
}
}
domsize = make([]uint64, n+1)
for _, x := range postorder {
domsize[x] += d.Size(x)
domsize[idom[x]] += domsize[x]
}
// Note: unreachable objects will have domsize of 0.
}