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cmd/compile: optimize scope tracking
1. Detect and remove the markers of lexical scopes that don't contain any variables early in noder, instead of waiting until the end of DWARF generation. This saves memory by never allocating some of the markers and optimizes some of the algorithms that depend on the number of scopes. 2. Assign scopes to Progs by doing, for each Prog, a binary search over the markers array. This is faster, compared to sorting the Prog list because there are fewer markers than there are Progs. completed 15 of 15, estimated time remaining 0s (eta 2:30PM) name old time/op new time/op delta Template 274ms ± 5% 260ms ± 6% -4.91% (p=0.000 n=15+15) Unicode 126ms ± 5% 127ms ± 9% ~ (p=0.856 n=13+15) GoTypes 861ms ± 5% 857ms ± 4% ~ (p=0.595 n=15+15) Compiler 4.11s ± 4% 4.12s ± 5% ~ (p=1.000 n=15+15) SSA 10.7s ± 2% 10.9s ± 4% +2.01% (p=0.002 n=14+14) Flate 163ms ± 4% 166ms ± 9% ~ (p=0.134 n=14+15) GoParser 203ms ± 4% 205ms ± 6% ~ (p=0.461 n=15+15) Reflect 544ms ± 5% 549ms ± 4% ~ (p=0.174 n=15+15) Tar 249ms ± 9% 245ms ± 6% ~ (p=0.285 n=15+15) XML 286ms ± 4% 291ms ± 5% ~ (p=0.081 n=15+15) [Geo mean] 528ms 529ms +0.14% name old user-time/op new user-time/op delta Template 358ms ± 7% 354ms ± 5% ~ (p=0.242 n=14+15) Unicode 189ms ±11% 191ms ±10% ~ (p=0.438 n=15+15) GoTypes 1.15s ± 4% 1.14s ± 3% ~ (p=0.405 n=15+15) Compiler 5.36s ± 6% 5.35s ± 5% ~ (p=0.588 n=15+15) SSA 14.6s ± 3% 15.0s ± 4% +2.58% (p=0.000 n=15+15) Flate 214ms ±12% 216ms ± 8% ~ (p=0.539 n=15+15) GoParser 267ms ± 6% 270ms ± 5% ~ (p=0.569 n=15+15) Reflect 712ms ± 5% 709ms ± 4% ~ (p=0.894 n=15+15) Tar 329ms ± 8% 330ms ± 5% ~ (p=0.974 n=14+15) XML 371ms ± 3% 381ms ± 5% +2.85% (p=0.002 n=13+15) [Geo mean] 705ms 709ms +0.62% name old alloc/op new alloc/op delta Template 38.0MB ± 0% 38.4MB ± 0% +1.27% (p=0.000 n=15+14) Unicode 28.8MB ± 0% 28.8MB ± 0% +0.16% (p=0.000 n=15+14) GoTypes 112MB ± 0% 114MB ± 0% +1.64% (p=0.000 n=15+15) Compiler 465MB ± 0% 474MB ± 0% +1.91% (p=0.000 n=15+15) SSA 1.48GB ± 0% 1.53GB ± 0% +3.32% (p=0.000 n=15+15) Flate 24.3MB ± 0% 24.8MB ± 0% +1.77% (p=0.000 n=14+15) GoParser 30.7MB ± 0% 31.1MB ± 0% +1.27% (p=0.000 n=15+15) Reflect 76.3MB ± 0% 77.1MB ± 0% +1.03% (p=0.000 n=15+15) Tar 39.2MB ± 0% 39.6MB ± 0% +1.02% (p=0.000 n=13+15) XML 41.5MB ± 0% 42.1MB ± 0% +1.45% (p=0.000 n=15+15) [Geo mean] 77.5MB 78.7MB +1.48% name old allocs/op new allocs/op delta Template 385k ± 0% 387k ± 0% +0.54% (p=0.000 n=15+15) Unicode 342k ± 0% 343k ± 0% +0.10% (p=0.000 n=15+15) GoTypes 1.19M ± 0% 1.19M ± 0% +0.64% (p=0.000 n=14+15) Compiler 4.51M ± 0% 4.54M ± 0% +0.53% (p=0.000 n=15+15) SSA 12.2M ± 0% 12.4M ± 0% +1.16% (p=0.000 n=15+15) Flate 234k ± 0% 236k ± 0% +0.63% (p=0.000 n=14+15) GoParser 318k ± 0% 320k ± 0% +0.63% (p=0.000 n=15+15) Reflect 974k ± 0% 977k ± 0% +0.28% (p=0.000 n=15+15) Tar 395k ± 0% 397k ± 0% +0.38% (p=0.000 n=15+13) XML 404k ± 0% 407k ± 0% +0.55% (p=0.000 n=15+15) [Geo mean] 794k 799k +0.55% name old text-bytes new text-bytes delta HelloSize 680kB ± 0% 680kB ± 0% ~ (all equal) name old data-bytes new data-bytes delta HelloSize 9.62kB ± 0% 9.62kB ± 0% ~ (all equal) name old bss-bytes new bss-bytes delta HelloSize 125kB ± 0% 125kB ± 0% ~ (all equal) name old exe-bytes new exe-bytes delta HelloSize 1.11MB ± 0% 1.12MB ± 0% +1.11% (p=0.000 n=15+15) Change-Id: I95a0173ee28c52be1a4851d2a6e389529e74bf28 Reviewed-on: https://go-review.googlesource.com/95396 Run-TryBot: Alberto Donizetti <alb.donizetti@gmail.com> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Matthew Dempsky <mdempsky@google.com> Reviewed-by: Heschi Kreinick <heschi@google.com>
This commit is contained in:
Alessandro Arzilli
Alberto Donizetti
parent
1023b016d5
commit
3fca7306f4
@ -128,6 +128,12 @@ type noder struct {
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pragcgobuf string
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err chan syntax.Error
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scope ScopeID
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// scopeVars is a stack tracking the number of variables declared in the
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// current function at the moment each open scope was opened.
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scopeVars []int
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lastCloseScopePos syntax.Pos
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}
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func (p *noder) funchdr(n *Node) ScopeID {
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@ -147,6 +153,7 @@ func (p *noder) openScope(pos syntax.Pos) {
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if trackScopes {
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Curfn.Func.Parents = append(Curfn.Func.Parents, p.scope)
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p.scopeVars = append(p.scopeVars, len(Curfn.Func.Dcl))
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p.scope = ScopeID(len(Curfn.Func.Parents))
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p.markScope(pos)
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@ -154,9 +161,34 @@ func (p *noder) openScope(pos syntax.Pos) {
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}
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func (p *noder) closeScope(pos syntax.Pos) {
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p.lastCloseScopePos = pos
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types.Popdcl()
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if trackScopes {
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scopeVars := p.scopeVars[len(p.scopeVars)-1]
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p.scopeVars = p.scopeVars[:len(p.scopeVars)-1]
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if scopeVars == len(Curfn.Func.Dcl) {
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// no variables were declared in this scope, so we can retract it.
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if int(p.scope) != len(Curfn.Func.Parents) {
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Fatalf("scope tracking inconsistency, no variables declared but scopes were not retracted")
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}
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p.scope = Curfn.Func.Parents[p.scope-1]
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Curfn.Func.Parents = Curfn.Func.Parents[:len(Curfn.Func.Parents)-1]
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nmarks := len(Curfn.Func.Marks)
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Curfn.Func.Marks[nmarks-1].Scope = p.scope
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prevScope := ScopeID(0)
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if nmarks >= 2 {
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prevScope = Curfn.Func.Marks[nmarks-2].Scope
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}
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if Curfn.Func.Marks[nmarks-1].Scope == prevScope {
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Curfn.Func.Marks = Curfn.Func.Marks[:nmarks-1]
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}
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return
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}
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p.scope = Curfn.Func.Parents[p.scope-1]
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p.markScope(pos)
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@ -177,12 +209,7 @@ func (p *noder) markScope(pos syntax.Pos) {
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// "if" statements, as their implicit blocks always end at the same
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// position as an explicit block.
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func (p *noder) closeAnotherScope() {
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types.Popdcl()
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if trackScopes {
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p.scope = Curfn.Func.Parents[p.scope-1]
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Curfn.Func.Marks[len(Curfn.Func.Marks)-1].Scope = p.scope
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}
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p.closeScope(p.lastCloseScopePos)
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}
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// linkname records a //go:linkname directive.
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@ -87,21 +87,12 @@ func scopePCs(fnsym *obj.LSym, marks []Mark, dwarfScopes []dwarf.Scope) {
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pcs = append(pcs, scopedPCs{start: p0.Pc, end: fnsym.Size, pos: p0.Pos})
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}
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// Sort PCs by source position, and walk in parallel with
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// scope marks to assign a lexical scope to each PC interval.
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sort.Sort(pcsByPos(pcs))
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var marki int
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var scope ScopeID
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// Assign scopes to each chunk of instructions.
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for i := range pcs {
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for marki < len(marks) && !xposBefore(pcs[i].pos, marks[marki].Pos) {
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scope = marks[marki].Scope
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marki++
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}
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pcs[i].scope = scope
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pcs[i].scope = findScope(marks, pcs[i].pos)
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}
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// Re-sort to create sorted PC ranges for each DWARF scope.
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sort.Sort(pcsByPC(pcs))
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// Create sorted PC ranges for each DWARF scope.
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for _, pc := range pcs {
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r := &dwarfScopes[pc.scope].Ranges
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if i := len(*r); i > 0 && (*r)[i-1].End == pc.start {
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@ -113,23 +104,6 @@ func scopePCs(fnsym *obj.LSym, marks []Mark, dwarfScopes []dwarf.Scope) {
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}
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func compactScopes(dwarfScopes []dwarf.Scope) []dwarf.Scope {
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// Forward pass to collapse empty scopes into parents.
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remap := make([]int32, len(dwarfScopes))
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j := int32(1)
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for i := 1; i < len(dwarfScopes); i++ {
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s := &dwarfScopes[i]
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s.Parent = remap[s.Parent]
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if len(s.Vars) == 0 {
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dwarfScopes[s.Parent].UnifyRanges(s)
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remap[i] = s.Parent
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continue
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}
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remap[i] = j
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dwarfScopes[j] = *s
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j++
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}
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dwarfScopes = dwarfScopes[:j]
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// Reverse pass to propagate PC ranges to parent scopes.
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for i := len(dwarfScopes) - 1; i > 0; i-- {
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s := &dwarfScopes[i]
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@ -147,14 +121,6 @@ func (s pcsByPC) Less(i, j int) bool {
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return s[i].start < s[j].start
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}
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type pcsByPos []scopedPCs
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func (s pcsByPos) Len() int { return len(s) }
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func (s pcsByPos) Swap(i, j int) { s[i], s[j] = s[j], s[i] }
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func (s pcsByPos) Less(i, j int) bool {
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return xposBefore(s[i].pos, s[j].pos)
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}
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type varsByScopeAndOffset struct {
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vars []*dwarf.Var
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scopes []ScopeID
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@ -1304,6 +1304,11 @@ func putscope(ctxt Context, s *FnState, scopes []Scope, curscope int32, fnabbrev
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return curscope
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}
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if len(scopes[curscope].Vars) == 0 {
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curscope = putscope(ctxt, s, scopes, curscope, fnabbrev, encbuf)
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continue
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}
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if len(scope.Ranges) == 1 {
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Uleb128put(ctxt, s.Info, DW_ABRV_LEXICAL_BLOCK_SIMPLE)
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putattr(ctxt, s.Info, DW_ABRV_LEXICAL_BLOCK_SIMPLE, DW_FORM_addr, DW_CLS_ADDRESS, scope.Ranges[0].Start, s.StartPC)
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@ -1316,6 +1321,7 @@ func putscope(ctxt Context, s *FnState, scopes []Scope, curscope int32, fnabbrev
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}
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curscope = putscope(ctxt, s, scopes, curscope, fnabbrev, encbuf)
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Uleb128put(ctxt, s.Info, 0)
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}
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return curscope
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