From: Austin Clements <austin@google.com>
Date: Thu, 26 May 2016 02:59:19 +0000 (-0400)
Subject: cmd/link/internal/ld: fix DWARF offsets with GOEXPERIMENT=framepointer
X-Git-Tag: go1.7beta1~82
X-Git-Url: http://www.git.cypherpunks.su/?a=commitdiff_plain;h=adff422779709c83db91700fdcc0a0bd5dee6a21;p=gostls13.git

cmd/link/internal/ld: fix DWARF offsets with GOEXPERIMENT=framepointer

The offsets computed by the DWARF expressions for local variables
currently don't account for the extra stack slot used by the frame
pointer when GOEXPERIMENT=framepointer is enabled.

Fix this by adding the extra stack slot to the offset.

This fixes TestGdbPython with GOEXPERIMENT=framepointer.

Updates #15840.

Change-Id: I1b2ebb2750cd22266f4a89ec8d9e8bfa05fabd19
Reviewed-on: https://go-review.googlesource.com/23458
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
---

diff --git a/src/cmd/link/internal/ld/dwarf.go b/src/cmd/link/internal/ld/dwarf.go
index bf1a7e74c1..ca86e72d83 100644
--- a/src/cmd/link/internal/ld/dwarf.go
+++ b/src/cmd/link/internal/ld/dwarf.go
@@ -1558,6 +1558,12 @@ func writelines(prev *LSym) *LSym {
 				if !haslinkregister() {
 					offs -= int64(SysArch.PtrSize)
 				}
+				if obj.Framepointer_enabled != 0 {
+					// The frame pointer is saved
+					// between the CFA and the
+					// autos.
+					offs -= int64(SysArch.PtrSize)
+				}
 
 			case obj.A_PARAM:
 				dt = DW_ABRV_PARAM