https://github.com/nextsilicon-itay-bookstein created
https://github.com/llvm/llvm-project/pull/186672
After 42b638c6b40d ("Propagate dependencies to OBJECT libraries in
add_llvm_library"), obj.clangSupport now inherits clangSupport's LINK_LIBRARIES
via target_link_libraries, which includes libLLVM.so when LLVM_LINK_LLVM_DYLIB
is enabled.
Previously the obj.clangSupport alias path was harmless because the OBJECT
library carried no link dependencies. Now, aliasing clangSupport_tablegen to
obj.clangSupport in DYLIB mode causes clang-tblgen to transitively link
libLLVM.so, while also having LLVM symbols compiled in statically — triggering
an ASan ODR violation on globals like llvm::vfs::FileSystem::ID.
Fix by checking LLVM_LINK_LLVM_DYLIB first and unconditionally taking the
DISABLE_LLVM_LINK_LLVM_DYLIB static rebuild path in that case, regardless of
whether obj.clangSupport exists.
>From 36105764b3e2640fdcb311f2bdd68a579299564e Mon Sep 17 00:00:00 2001
From: Itay Bookstein <[email protected]>
Date: Sun, 15 Mar 2026 16:24:56 +0200
Subject: [PATCH] [clang][CMake] Fix clangSupport_tablegen ODR violation with
LLVM_LINK_LLVM_DYLIB
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
After 42b638c6b40d ("Propagate dependencies to OBJECT libraries in
add_llvm_library"), obj.clangSupport now inherits clangSupport's
LINK_LIBRARIES via target_link_libraries, which includes libLLVM.so
when LLVM_LINK_LLVM_DYLIB is enabled.
Previously the obj.clangSupport alias path was harmless because the
OBJECT library carried no link dependencies. Now, aliasing
clangSupport_tablegen to obj.clangSupport in DYLIB mode causes
clang-tblgen to transitively link libLLVM.so, while also having LLVM
symbols compiled in statically — triggering an ASan ODR violation on
globals like llvm::vfs::FileSystem::ID.
Fix by checking LLVM_LINK_LLVM_DYLIB first and unconditionally taking
the DISABLE_LLVM_LINK_LLVM_DYLIB static rebuild path in that case,
regardless of whether obj.clangSupport exists.
---
clang/lib/Support/CMakeLists.txt | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)
diff --git a/clang/lib/Support/CMakeLists.txt b/clang/lib/Support/CMakeLists.txt
index de06271e914ae..d00a9cd023873 100644
--- a/clang/lib/Support/CMakeLists.txt
+++ b/clang/lib/Support/CMakeLists.txt
@@ -15,11 +15,7 @@ set(clangSupport_sources
add_clang_library(clangSupport ${clangSupport_sources})
-if (TARGET obj.clangSupport)
- add_library(clangSupport_tablegen ALIAS obj.clangSupport)
-elseif (NOT LLVM_LINK_LLVM_DYLIB)
- add_library(clangSupport_tablegen ALIAS clangSupport)
-else()
+if (LLVM_LINK_LLVM_DYLIB)
# Build a version of the support library that does not link against
# libLLVM-*.so, to be used by clang-tblgen. This is so clang-tblgen doesn't
# link against libLLVMSupport twice (once statically and once via
@@ -27,6 +23,10 @@ else()
add_llvm_library(clangSupport_tablegen
BUILDTREE_ONLY STATIC DISABLE_LLVM_LINK_LLVM_DYLIB
${clangSupport_sources})
+elseif (TARGET obj.clangSupport)
+ add_library(clangSupport_tablegen ALIAS obj.clangSupport)
+else()
+ add_library(clangSupport_tablegen ALIAS clangSupport)
endif()
set(LLVM_COMMON_DEPENDS ${LLVM_COMMON_DEPENDS_OLD})
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