From: Than McIntosh <thanm@google.com>
Date: Tue, 13 Apr 2021 17:49:55 +0000 (-0400)
Subject: cmd/internal/obj: don't emit args_stackmap for ABIInternal asm funcs
X-Git-Tag: go1.17beta1~654
X-Git-Url: http://www.git.cypherpunks.su/?a=commitdiff_plain;h=4480c822ba;p=gostls13.git

cmd/internal/obj: don't emit args_stackmap for ABIInternal asm funcs

The compiler currently emits an "*.args_stackmap" symbol for all
bodyless functions, so that asm functions will have the proper stack
map. At the moment the code in the compiler that emits args_stackmap
assumes ABI0; to avoid misleading stackmaps, turn off args_stackmap
generation for non-ABI0 asm functions.

Updates #40724.

Change-Id: Ia5e3528d56da5fb107e799bd658e52496ba4a331
Reviewed-on: https://go-review.googlesource.com/c/go/+/309790
Trust: Than McIntosh <thanm@google.com>
Run-TryBot: Than McIntosh <thanm@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Austin Clements <austin@google.com>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
---

diff --git a/src/cmd/internal/obj/plist.go b/src/cmd/internal/obj/plist.go
index 9dbad20589..54b035bb96 100644
--- a/src/cmd/internal/obj/plist.go
+++ b/src/cmd/internal/obj/plist.go
@@ -85,6 +85,13 @@ func Flushplist(ctxt *Link, plist *Plist, newprog ProgAlloc, myimportpath string
 			// wrapper function
 			continue
 		}
+		// The current args_stackmap generation in the compiler assumes
+		// that the function in question is ABI0, so avoid introducing
+		// an args_stackmap reference if the func is not ABI0 (better to
+		// have no stackmap than an incorrect/lying stackmap).
+		if s.ABI() != ABI0 {
+			continue
+		}
 		found := false
 		for p := s.Func().Text; p != nil; p = p.Link {
 			if p.As == AFUNCDATA && p.From.Type == TYPE_CONST && p.From.Offset == objabi.FUNCDATA_ArgsPointerMaps {
@@ -92,7 +99,6 @@ func Flushplist(ctxt *Link, plist *Plist, newprog ProgAlloc, myimportpath string
 				break
 			}
 		}
-
 		if !found {
 			p := Appendp(s.Func().Text, newprog)
 			p.As = AFUNCDATA