From: Cherry Mui <cherryyz@google.com>
Date: Tue, 20 Dec 2022 22:26:18 +0000 (-0500)
Subject: runtime/internal/startlinetest: work around shared buildmode linking issue
X-Git-Tag: go1.20rc2~1^2~9
X-Git-Url: http://www.git.cypherpunks.su/?a=commitdiff_plain;h=de6abd78893e91f26337eb399644b7a6bc3ea583;p=gostls13.git

runtime/internal/startlinetest: work around shared buildmode linking issue

The runtime/internal/startlinetest package contains a call to a
function defined in runtime_test. Generally this is fine as this
package is only linked in for runtime_test. Except that for "go
install -buildmode=shared std", which include all packages in std,
including this test-only internal package. In this mode, the
caller is included in the linking but the callee is not, causing
linking error. Work around it by calling
runtime_test.callerStartLine via a function pointer. The function
pointer is only set in runtime_test. In the shared std build, the
function pointer will not be set, and this is fine.

Fixes #57334.

Change-Id: I7d871c50ce6599c6ea2802cf6e14bb749deab220
Reviewed-on: https://go-review.googlesource.com/c/go/+/458696
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@google.com>
Run-TryBot: Cherry Mui <cherryyz@google.com>
---

diff --git a/src/runtime/internal/startlinetest/func_amd64.go b/src/runtime/internal/startlinetest/func_amd64.go
index 6cd9a3f417..ab7063d615 100644
--- a/src/runtime/internal/startlinetest/func_amd64.go
+++ b/src/runtime/internal/startlinetest/func_amd64.go
@@ -8,3 +8,6 @@ package startlinetest
 // Defined in func_amd64.s, this is a trivial assembly function that calls
 // runtime_test.callerStartLine.
 func AsmFunc() int
+
+// Provided by runtime_test.
+var CallerStartLine func(bool) int
diff --git a/src/runtime/internal/startlinetest/func_amd64.s b/src/runtime/internal/startlinetest/func_amd64.s
index ace5b34e70..96982bedab 100644
--- a/src/runtime/internal/startlinetest/func_amd64.s
+++ b/src/runtime/internal/startlinetest/func_amd64.s
@@ -23,5 +23,6 @@
 TEXT	·AsmFunc<ABIInternal>(SB),NOSPLIT,$8-0
 	NO_LOCAL_POINTERS
 	MOVQ	$0, AX // wantInlined
-	CALL    runtime_test·callerStartLine<ABIInternal>(SB)
+	MOVQ	·CallerStartLine(SB), DX
+	CALL	(DX)
 	RET
diff --git a/src/runtime/start_line_amd64_test.go b/src/runtime/start_line_amd64_test.go
index 57001e71de..305ed0b126 100644
--- a/src/runtime/start_line_amd64_test.go
+++ b/src/runtime/start_line_amd64_test.go
@@ -13,6 +13,8 @@ import (
 // is only tested on amd64 to avoid the need for a proliferation of per-arch
 // copies of this function.
 func TestStartLineAsm(t *testing.T) {
+	startlinetest.CallerStartLine = callerStartLine
+
 	const wantLine = 23
 	got := startlinetest.AsmFunc()
 	if got != wantLine {