From: Josh Bleecher Snyder <josharian@gmail.com>
Date: Fri, 24 Sep 2021 20:50:22 +0000 (-0700)
Subject: cmd/link: move all FUNCDATA refs into go.func.*
X-Git-Tag: go1.18beta1~1057
X-Git-Url: http://www.git.cypherpunks.su/?a=commitdiff_plain;h=cfd74f7727f6ad5a81d574c28cbee52cc13fdc52;p=gostls13.git

cmd/link: move all FUNCDATA refs into go.func.*

This change moves all symbols referred to by FUNCDATA
into go.func.* and go.funcrel.*.

Surprisingly (because it inhibits some content-addressability),
it shrinks binaries by a little bit, about 0.1%.

This paves the way for a subsequent change to change
FUNCDATA relocations to offsets.

Change-Id: I70e487205073699f442192b0791cc92da5663057
Reviewed-on: https://go-review.googlesource.com/c/go/+/352189
Trust: Josh Bleecher Snyder <josharian@gmail.com>
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Cherry Mui <cherryyz@google.com>
---

diff --git a/src/cmd/internal/obj/objfile.go b/src/cmd/internal/obj/objfile.go
index 0f3356f85e..687cddc70c 100644
--- a/src/cmd/internal/obj/objfile.go
+++ b/src/cmd/internal/obj/objfile.go
@@ -408,7 +408,21 @@ func contentHashSection(s *LSym) byte {
 	name := s.Name
 	if s.IsPcdata() {
 		return 'P'
-	} else if strings.HasPrefix(name, "type.") {
+	}
+	if strings.HasPrefix(name, "runtime.gcbits.") {
+		return 'G' // gcbits
+	}
+	if strings.HasPrefix(name, "gcargs.") ||
+		strings.HasPrefix(name, "gclocals.") ||
+		strings.HasPrefix(name, "gclocals·") ||
+		strings.HasSuffix(name, ".opendefer") ||
+		strings.HasSuffix(name, ".arginfo0") ||
+		strings.HasSuffix(name, ".arginfo1") ||
+		strings.HasSuffix(name, ".args_stackmap") ||
+		strings.HasSuffix(name, ".stkobj") {
+		return 'F' // go.func.* or go.funcrel.*
+	}
+	if strings.HasPrefix(name, "type.") {
 		return 'T'
 	}
 	return 0
diff --git a/src/cmd/link/internal/ld/symtab.go b/src/cmd/link/internal/ld/symtab.go
index 5e7eeeb94f..7fddc59bb5 100644
--- a/src/cmd/link/internal/ld/symtab.go
+++ b/src/cmd/link/internal/ld/symtab.go
@@ -507,13 +507,9 @@ func (ctxt *Link) symtab(pcln *pclntab) []sym.SymKind {
 		symgcbits   = groupSym("runtime.gcbits.*", sym.SGCBITS)
 	)
 
-	var symgofuncrel loader.Sym
-	if !ctxt.DynlinkingGo() {
-		if ctxt.UseRelro() {
-			symgofuncrel = groupSym("go.funcrel.*", sym.SGOFUNCRELRO)
-		} else {
-			symgofuncrel = symgofunc
-		}
+	symgofuncrel := symgofunc
+	if ctxt.UseRelro() {
+		symgofuncrel = groupSym("go.funcrel.*", sym.SGOFUNCRELRO)
 	}
 
 	symt := ldr.CreateSymForUpdate("runtime.symtab", 0)
@@ -555,7 +551,7 @@ func (ctxt *Link) symtab(pcln *pclntab) []sym.SymKind {
 			}
 			if ctxt.UseRelro() {
 				symGroupType[s] = sym.SGOFUNCRELRO
-				if symgofuncrel != 0 {
+				if !ctxt.DynlinkingGo() {
 					ldr.SetCarrierSym(s, symgofuncrel)
 				}
 			} else {
@@ -569,10 +565,17 @@ func (ctxt *Link) symtab(pcln *pclntab) []sym.SymKind {
 			ldr.SymType(s) == sym.SGOFUNC && s != symgofunc, // inltree, see pcln.go
 			strings.HasSuffix(name, ".opendefer"),
 			strings.HasSuffix(name, ".arginfo0"),
-			strings.HasSuffix(name, ".arginfo1"):
-			symGroupType[s] = sym.SGOFUNC
+			strings.HasSuffix(name, ".arginfo1"),
+			strings.HasSuffix(name, ".args_stackmap"),
+			strings.HasSuffix(name, ".stkobj"):
 			ldr.SetAttrNotInSymbolTable(s, true)
-			ldr.SetCarrierSym(s, symgofunc)
+			if ctxt.UseRelro() && strings.HasSuffix(name, ".stkobj") {
+				symGroupType[s] = sym.SGOFUNCRELRO
+				ldr.SetCarrierSym(s, symgofuncrel)
+			} else {
+				symGroupType[s] = sym.SGOFUNC
+				ldr.SetCarrierSym(s, symgofunc)
+			}
 			if ctxt.Debugvlog != 0 {
 				align := ldr.SymAlign(s)
 				liveness += (ldr.SymSize(s) + int64(align) - 1) &^ (int64(align) - 1)