[Lldb-commits] [lldb] [lldb] Remove internal linkage from roundtripJSON (NFC) (PR #222119)

[Med Ismail Bennani via lldb-commits]

https://github.com/medismailben created https://github.com/llvm/llvm-project/pull/222119

`static` on a namespace-scope function template gives every instantiation internal linkage, so each translation unit including TestingSupport/TestUtilities.h gets its own copy and -Wunused-template fires in any of them that never calls roundtripJSON. That is 52 of the 57 unit test files which include the header:

  lldb/unittests/TestingSupport/TestUtilities.h:68:48: error: unused
  function template 'roundtripJSON' [-Werror,-Wunused-template]

1529d35adbd6, the reland of #206123, added -Wunused-template to -Wall, which makes this a hard error under -Werror. That change is currently reverted on main by 8710728e0418, so a compiler built from main today does not surface it. It did ship in clang 23.1.0 though, because the revert landed too late to make that tag and only reached the release branch in 23.1.1, so building LLDB with a released 23.1.0 compiler hits this now.

Function templates already have vague linkage, so `static` bought nothing here and only narrowed it. Drop it, matching da6918474bb7 and 1376072719a0 in MLIR.

>From 2c5c5041643f92366e0c5c2d011c93f5110fc25d Mon Sep 17 00:00:00 2001
From: Med Ismail Bennani <ismail at bennani.ma>
Date: Tue, 8 Sep 2026 20:48:31 +0100
Subject: [PATCH] [lldb][NFC] Remove internal linkage from roundtripJSON

`static` on a namespace-scope function template gives every instantiation
internal linkage, so each translation unit including
TestingSupport/TestUtilities.h gets its own copy and -Wunused-template
fires in any of them that never calls roundtripJSON. That is 52 of the 57
unit test files which include the header:

  lldb/unittests/TestingSupport/TestUtilities.h:68:48: error: unused
  function template 'roundtripJSON' [-Werror,-Wunused-template]

1529d35adbd6, the reland of #206123, added -Wunused-template to -Wall,
which makes this a hard error under -Werror. That change is currently
reverted on main by 8710728e0418, so a compiler built from main today does
not surface it. It did ship in clang 23.1.0 though, because the revert
landed too late to make that tag and only reached the release branch in
23.1.1, so building LLDB with a released 23.1.0 compiler hits this now.

Function templates already have vague linkage, so `static` bought nothing
here and only narrowed it. Drop it, matching da6918474bb7 and 1376072719a0
in MLIR.

Signed-off-by: Med Ismail Bennani <ismail at bennani.ma>
---
 lldb/unittests/TestingSupport/TestUtilities.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lldb/unittests/TestingSupport/TestUtilities.h b/lldb/unittests/TestingSupport/TestUtilities.h
index 68b4dbc127a7d..f322716eb6977 100644
--- a/lldb/unittests/TestingSupport/TestUtilities.h
+++ b/lldb/unittests/TestingSupport/TestUtilities.h
@@ -65,7 +65,7 @@ class TestFile {
   std::string Buffer;
 };
 
-template <typename T> static llvm::Expected<T> roundtripJSON(const T &input) {
+template <typename T> llvm::Expected<T> roundtripJSON(const T &input) {
   std::string encoded;
   llvm::raw_string_ostream OS(encoded);
   OS << toJSON(input);