From 4098ab3ff4de53df4bf2e9b2db0f49e4d12b3d9c Mon Sep 17 00:00:00 2001 From: Cherry Zhang Date: Mon, 11 May 2020 15:11:36 -0400 Subject: [PATCH] [dev.link] cmd/link: reduce allocations in Preload MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit Don't create loader.Syms until LoadFull (it will be gone soon anyway.) Preallocate loader.objSym array. Don't create loader.values until preloading is done. Linking cmd/compile: name old alloc/op new alloc/op delta Loadlib_GC 36.2MB ± 0% 20.0MB ± 0% -44.91% (p=0.016 n=5+4) Change-Id: I82eddcfa7fb8fc4e84e8174a47e59cf1183dd83b Reviewed-on: https://go-review.googlesource.com/c/go/+/233341 Run-TryBot: Cherry Zhang TryBot-Result: Gobot Gobot Reviewed-by: Than McIntosh Reviewed-by: Jeremy Faller --- src/cmd/link/internal/loader/loader.go | 13 ++++++------- 1 file changed, 6 insertions(+), 7 deletions(-) diff --git a/src/cmd/link/internal/loader/loader.go b/src/cmd/link/internal/loader/loader.go index 0990768903..e906ec3d5e 100644 --- a/src/cmd/link/internal/loader/loader.go +++ b/src/cmd/link/internal/loader/loader.go @@ -338,8 +338,8 @@ func NewLoader(flags uint32, elfsetstring elfsetstringFunc, reporter *ErrorRepor nbuiltin := goobj2.NBuiltin() ldr := &Loader{ start: make(map[*oReader]Sym), - objs: []objIdx{{}}, // reserve index 0 for nil symbol - objSyms: []objSym{{}}, // reserve index 0 for nil symbol + objs: []objIdx{{}}, // reserve index 0 for nil symbol + objSyms: make([]objSym, 1, 100000), // reserve index 0 for nil symbol extReader: &oReader{}, symsByName: [2]map[string]Sym{make(map[string]Sym, 100000), make(map[string]Sym, 50000)}, // preallocate ~2MB for ABI0 and ~1MB for ABI1 symbols objByPkg: make(map[string]*oReader), @@ -463,7 +463,8 @@ func (l *Loader) newExtSym(name string, ver int) Sym { if l.extStart == 0 { l.extStart = i } - l.growSyms(int(i)) + l.growValues(int(i) + 1) + l.growAttrBitmaps(int(i) + 1) pi := l.newPayload(name, ver) l.objSyms = append(l.objSyms, objSym{l.extReader, int(pi)}) l.extReader.syms = append(l.extReader.syms, i) @@ -1180,7 +1181,7 @@ func (l *Loader) SymSect(i Sym) *sym.Section { return l.sects[l.symSects[i]] } -// SetSymValue sets the section of the i-th symbol. i is global index. +// SetSymSect sets the section of the i-th symbol. i is global index. func (l *Loader) SetSymSect(i Sym, sect *sym.Section) { if int(i) >= len(l.symSects) { l.symSects = append(l.symSects, make([]uint16, l.NSym()-len(l.symSects))...) @@ -1960,7 +1961,6 @@ func (l *Loader) preloadSyms(r *oReader, kind int) { default: panic("preloadSyms: bad kind") } - l.growSyms(len(l.objSyms) + end - start) l.growAttrBitmaps(len(l.objSyms) + end - start) for i := start; i < end; i++ { osym := r.Sym(i) @@ -2007,6 +2007,7 @@ func (l *Loader) LoadNonpkgSyms(arch *sys.Arch) { for _, o := range l.objs[1:] { loadObjRefs(l, o.r, arch) } + l.values = make([]int64, l.NSym(), l.NSym()+1000) // +1000 make some room for external symbols } func loadObjRefs(l *Loader, r *oReader, arch *sys.Arch) { @@ -2535,12 +2536,10 @@ func loadObjSyms(l *Loader, syms *sym.Symbols, r *oReader, needReloc, needExtRel // a symbol originally discovered as part of an object file, it's // easier to do this if we make the updates to an external symbol // payload. -// XXX maybe rename? makeExtPayload? func (l *Loader) cloneToExternal(symIdx Sym) { if l.IsExternal(symIdx) { panic("sym is already external, no need for clone") } - l.growSyms(int(symIdx)) // Read the particulars from object. r, li := l.toLocal(symIdx) -- 2.48.1