From: Than McIntosh <thanm@google.com>
Date: Tue, 10 Mar 2020 14:08:50 +0000 (-0400)
Subject: [dev.link] cmd/link: use shared reloc slice in writelines method
X-Git-Tag: go1.15beta1~679^2~88
X-Git-Url: http://www.git.cypherpunks.su/?a=commitdiff_plain;h=69d9664f18803b01927f27b607fa565301f7873e;p=gostls13.git

[dev.link] cmd/link: use shared reloc slice in writelines method

Move to a shared/reused slice of loader.Reloc's in a couple of places
in the linker's DWARF writelines method, as opposed to allocating a
new slice each time. Small performance improvement.

Change-Id: I06c64cf7ca00162d24d9421f1d6405c8808ebb83
Reviewed-on: https://go-review.googlesource.com/c/go/+/222758
Run-TryBot: Than McIntosh <thanm@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
---

diff --git a/src/cmd/link/internal/ld/dwarf.go b/src/cmd/link/internal/ld/dwarf.go
index b94e55fc2e..5e89b3897e 100644
--- a/src/cmd/link/internal/ld/dwarf.go
+++ b/src/cmd/link/internal/ld/dwarf.go
@@ -1213,11 +1213,12 @@ func (d *dwctxt2) writelines(unit *sym.CompilationUnit, ls loader.Sym) {
 
 	// Grab files for inlined functions.
 	// TODO: With difficulty, this could be moved into the compiler.
+	rslice := []loader.Reloc{}
 	for _, s := range unit.Textp2 {
 		fnSym := loader.Sym(s)
 		infosym, _, _, _ := d.ldr.GetFuncDwarfAuxSyms(fnSym)
 		drelocs := d.ldr.Relocs(infosym)
-		rslice := drelocs.ReadSyms(nil)
+		rslice = drelocs.ReadSyms(rslice)
 		for ri := 0; ri < len(rslice); ri++ {
 			r := &rslice[ri]
 			if r.Type != objabi.R_DWARFFILEREF {
@@ -1307,7 +1308,7 @@ func (d *dwctxt2) writelines(unit *sym.CompilationUnit, ls loader.Sym) {
 		fnu := d.ldr.MakeSymbolUpdater(fnSym)
 
 		relocs := d.ldr.Relocs(fnSym)
-		rslice := relocs.ReadAll(nil)
+		rslice = relocs.ReadAll(rslice)
 
 		for ri := range rslice {
 			r := &rslice[ri]