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cmd/compile: Drop references to Prog structs after each function
Don't accumulate a massive list of Prog structs during compilation and write them all out at the end of compilation. Instead, convert them to code+relocs (or data+relocs) after each function is compiled. Track down a few other places that were keeping Progs alive and nil them out so the Progs get GCd promptly. Saves ~20% in peak memory usage for the compiler. Surprisingly not much help speed-wise (only because we end up doing more GCs. With a compensating GOGC=120, it does help a bit), but this provides a base for more changes (e.g. reusing a cache of Progs). Change-Id: I838e01017c228995a687a8110d0cd67bf8596407 Reviewed-on: https://go-review.googlesource.com/19867 Run-TryBot: Keith Randall <[email protected]> TryBot-Result: Gobot Gobot <[email protected]> Reviewed-by: Josh Bleecher Snyder <[email protected]> Reviewed-by: Ian Lance Taylor <[email protected]>
1 parent fdd0179 commit 45c2e38

3 files changed

Lines changed: 28 additions & 5 deletions

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‎src/cmd/compile/internal/gc/dcl.go‎

Lines changed: 5 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -1449,8 +1449,13 @@ func funccompile(n *Node) {
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Funcdepth = n.Func.Depth + 1
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compile(n)
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Curfn = nil
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Pc = nil
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continpc = nil
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breakpc = nil
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Funcdepth = 0
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dclcontext = PEXTERN
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flushdata()
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obj.Flushplist(Ctxt) // convert from Prog list to machine code
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}
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func funcsym(s *Sym) *Sym {

‎src/cmd/compile/internal/gc/gsubr.go‎

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Original file line numberDiff line numberDiff line change
@@ -173,6 +173,18 @@ func dumpdata() {
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Clearp(Pc)
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}
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func flushdata() {
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if dfirst == nil {
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return
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}
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newplist()
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*Pc = *dfirst
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Pc = dpc
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Clearp(Pc)
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dfirst = nil
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dpc = nil
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}
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// Fixup instructions after allocauto (formerly compactframe) has moved all autos around.
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func fixautoused(p *obj.Prog) {
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for lp := &p; ; {

‎src/cmd/internal/obj/objfile.go‎

Lines changed: 11 additions & 5 deletions
Original file line numberDiff line numberDiff line change
@@ -302,16 +302,22 @@ func Flushplist(ctxt *Link) {
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ctxt.Arch.Assemble(ctxt, s)
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fieldtrack(ctxt, s)
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linkpcln(ctxt, s)
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s.Text = nil
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s.Etext = nil
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}
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// Add to running list in ctxt.
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if ctxt.Etext == nil {
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ctxt.Text = text
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} else {
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ctxt.Etext.Next = text
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if text != nil {
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if ctxt.Text == nil {
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ctxt.Text = text
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} else {
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ctxt.Etext.Next = text
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}
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ctxt.Etext = etext
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}
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ctxt.Etext = etext
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ctxt.Plist = nil
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ctxt.Plast = nil
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ctxt.Curp = nil
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}
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func Writeobjfile(ctxt *Link, b *Biobuf) {

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