From: Than McIntosh <thanm@google.com>
Date: Wed, 8 Jul 2020 14:43:42 +0000 (-0400)
Subject: [dev.link] cmd/link: fix ppc64-specific bug in genelfsym
X-Git-Tag: go1.16beta1~1378^2~11
X-Git-Url: http://www.git.cypherpunks.su/?a=commitdiff_plain;h=18ee3498805f81ef7f3435800bc5581599c61872;p=gostls13.git

[dev.link] cmd/link: fix ppc64-specific bug in genelfsym

The code in the the linker's genelfsym() routine was not properly
including runtime.text.%d marker symbols that are emitted on PPC64
when a very large text section is split into chunks. This bug was
introduced in CL 233338 when portions of asmb2() were converted
from sym.Symbol to loader.Sym usage.

Change-Id: Idfed944c41e1805f78f35be67bcdd18bdefd7819
Reviewed-on: https://go-review.googlesource.com/c/go/+/241498
Run-TryBot: Than McIntosh <thanm@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Reviewed-by: Jeremy Faller <jeremy@golang.org>
---

diff --git a/src/cmd/link/internal/ld/symtab.go b/src/cmd/link/internal/ld/symtab.go
index 97d7a22537..bc880955b8 100644
--- a/src/cmd/link/internal/ld/symtab.go
+++ b/src/cmd/link/internal/ld/symtab.go
@@ -180,12 +180,31 @@ func putelfsectionsym(ctxt *Link, out *OutBuf, s loader.Sym, shndx int) {
 func genelfsym(ctxt *Link, elfbind int) {
 	ldr := ctxt.loader
 
-	// Text symbols.
+	// runtime.text marker symbol(s).
 	s := ldr.Lookup("runtime.text", 0)
 	putelfsym(ctxt, s, STT_FUNC, elfbind)
+	for k, sect := range Segtext.Sections[1:] {
+		n := k + 1
+		if sect.Name != ".text" || (ctxt.IsAIX() && ctxt.IsExternal()) {
+			// On AIX, runtime.text.X are symbols already in the symtab.
+			break
+		}
+		s = ldr.Lookup(fmt.Sprintf("runtime.text.%d", n), 0)
+		if s == 0 {
+			break
+		}
+		if ldr.SymType(s) != sym.STEXT {
+			panic("unexpected type for runtime.text symbol")
+		}
+		putelfsym(ctxt, s, STT_FUNC, elfbind)
+	}
+
+	// Text symbols.
 	for _, s := range ctxt.Textp {
 		putelfsym(ctxt, s, STT_FUNC, elfbind)
 	}
+
+	// runtime.etext marker symbol.
 	s = ldr.Lookup("runtime.etext", 0)
 	if ldr.SymType(s) == sym.STEXT {
 		putelfsym(ctxt, s, STT_FUNC, elfbind)