From: isharipo <iskander.sharipov@intel.com>
Date: Thu, 17 May 2018 16:45:49 +0000 (+0300)
Subject: cmd/link/internal/ld: don't call fieldtrack if it's not enabled
X-Git-Tag: go1.11beta1~400
X-Git-Url: http://www.git.cypherpunks.su/?a=commitdiff_plain;h=8bb391312c7c2c8cde57c083eeb4390f992e3d88;p=gostls13.git

cmd/link/internal/ld: don't call fieldtrack if it's not enabled

If go toolchain is not built with GOEXPERIMENT=fieldtrack,
skip fieldtrack pass in the linker as it does full symtab traversal.

For linking "hello world" example from net/http:

	name      old time/op  new time/op  delta
	Linker-4   530ms ± 2%   525ms ± 2%  -1.03%  (p=0.028 n=17+19)

Fixes #20318
Updates #14624

Change-Id: I99336513db77d13f95f47d27339d76f01c42a5da
Reviewed-on: https://go-review.googlesource.com/113635
Run-TryBot: Iskander Sharipov <iskander.sharipov@intel.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
---

diff --git a/src/cmd/link/internal/ld/main.go b/src/cmd/link/internal/ld/main.go
index 8a812c924a..bfa3f70a9e 100644
--- a/src/cmd/link/internal/ld/main.go
+++ b/src/cmd/link/internal/ld/main.go
@@ -202,7 +202,9 @@ func Main(arch *sys.Arch, theArch Arch) {
 
 	ctxt.dostrdata()
 	deadcode(ctxt)
-	fieldtrack(ctxt)
+	if objabi.Fieldtrack_enabled != 0 {
+		fieldtrack(ctxt)
+	}
 	ctxt.callgraph()
 
 	ctxt.doelf()