From: Ian Lance Taylor <iant@golang.org>
Date: Thu, 4 Dec 2025 21:49:21 +0000 (-0800)
Subject: cmd/compile, runtime: set alignment of type descriptors
X-Git-Url: http://www.git.cypherpunks.su/?a=commitdiff_plain;h=a430bc1bd73ab9a7d4a0c740add9760914588396;p=gostls13.git

cmd/compile, runtime: set alignment of type descriptors

This trivial change reduces the size of cmd/go by 88K.

For #6853
For #36313

Change-Id: I5e74acf118bd1c63cbdd256879d8aa8d72a50505
Reviewed-on: https://go-review.googlesource.com/c/go/+/727021
Reviewed-by: Cherry Mui <cherryyz@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Keith Randall <khr@golang.org>
Reviewed-by: Carlos Amedee <carlos@golang.org>
Reviewed-by: Keith Randall <khr@google.com>
Auto-Submit: Ian Lance Taylor <iant@golang.org>
---

diff --git a/src/cmd/compile/internal/reflectdata/reflect.go b/src/cmd/compile/internal/reflectdata/reflect.go
index c3f041ec57..ea3d0b5b94 100644
--- a/src/cmd/compile/internal/reflectdata/reflect.go
+++ b/src/cmd/compile/internal/reflectdata/reflect.go
@@ -963,6 +963,7 @@ func writeType(t *types.Type) *obj.LSym {
 		keep = false
 	}
 	lsym.Set(obj.AttrMakeTypelink, keep)
+	lsym.Align = int16(types.PtrSize)
 
 	return lsym
 }
diff --git a/src/runtime/type.go b/src/runtime/type.go
index ae8da3bc29..1abd271c3f 100644
--- a/src/runtime/type.go
+++ b/src/runtime/type.go
@@ -535,16 +535,7 @@ func moduleTypelinks(md *moduledata) []*_type {
 
 	etypedesc := md.types + md.typedesclen
 	for td < etypedesc {
-		// TODO: The fact that type descriptors are aligned to
-		// 0x20 does not make sense.
-		if GOARCH == "arm" {
-			td = alignUp(td, 0x8)
-		} else if GOOS == "aix" {
-			// The alignment of 8 is forced in the linker on AIX.
-			td = alignUp(td, 0x8)
-		} else {
-			td = alignUp(td, 0x20)
-		}
+		td = alignUp(td, goarch.PtrSize)
 
 		typ := (*_type)(unsafe.Pointer(td))
 		ret = append(ret, typ)