From: Joel Sing <joel@sing.id.au>
Date: Tue, 13 Sep 2022 09:28:58 +0000 (+1000)
Subject: cmd/link: generate an error if the entry symbol cannot be found
X-Git-Tag: go1.20rc1~1072
X-Git-Url: http://www.git.cypherpunks.su/?a=commitdiff_plain;h=77420fa119643163f820be7752668a69100487d7;p=gostls13.git

cmd/link: generate an error if the entry symbol cannot be found

If the entry symbol cannot be found (for example, a new port is being brought
up and no rt0 code has been provided), the linker will currently panic. Rather
than panicing, generate an error that aids in debugging:

	missing entry symbol "_rt0_arm64_openbsd"

Change-Id: I9cc38eaab48f730d596ca7fa9e9e3d68250ae4d3
Reviewed-on: https://go-review.googlesource.com/c/go/+/430555
Auto-Submit: Jenny Rakoczy <jenny@golang.org>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Jenny Rakoczy <jenny@golang.org>
Run-TryBot: Cherry Mui <cherryyz@google.com>
Reviewed-by: Cherry Mui <cherryyz@google.com>
---

diff --git a/src/cmd/link/internal/ld/lib.go b/src/cmd/link/internal/ld/lib.go
index 14dc5433fb..ca343ab2f9 100644
--- a/src/cmd/link/internal/ld/lib.go
+++ b/src/cmd/link/internal/ld/lib.go
@@ -2435,6 +2435,10 @@ func Entryvalue(ctxt *Link) int64 {
 	}
 	ldr := ctxt.loader
 	s := ldr.Lookup(a, 0)
+	if s == 0 {
+		Errorf(nil, "missing entry symbol %q", a)
+		return 0
+	}
 	st := ldr.SymType(s)
 	if st == 0 {
 		return *FlagTextAddr