https://github.com/aaronpuchert created
https://github.com/llvm/llvm-project/pull/116556
The situation that required symbol versions on the LLVM shared library can also
happen for clang-cpp, although it is less common: different tools require
different versions of the library, and through transitive dependencies a
process ends up with multiple copies of clang-cpp. This causes havoc with ELF,
because calls meant to go one version of the library end up with another.
I've also considered introducing a symbol version globally, but for example the
clang (C) library and other targets outside of LLVM/Clang, e.g. libc++, would
not want that. So it's probably best if we keep it to those libraries.
>From c7c190d0809bc8fe86e04d1ff4d6719d7acdcbe2 Mon Sep 17 00:00:00 2001
From: Aaron Puchert <aaronpuch...@alice-dsl.net>
Date: Sun, 17 Nov 2024 21:17:35 +0100
Subject: [PATCH] Introduce symbol versioning for clang-cpp
The situation that required symbol versions on the LLVM shared library
can also happen for clang-cpp, although it is less common: different
tools require different versions of the library, and through transitive
dependencies a process ends up with multiple copies of clang-cpp. This
causes havoc with ELF, because calls meant to go one version of the
library end up with another.
I've also considered introducing a symbol version globally, but for
example the clang (C) library and other targets outside of LLVM/Clang,
e.g. libc++, would not want that. So it's probably best if we keep it to
those libraries.
---
clang/tools/clang-shlib/CMakeLists.txt | 8 ++++++++
clang/tools/clang-shlib/simple_version_script.map.in | 1 +
llvm/CMakeLists.txt | 2 +-
3 files changed, 10 insertions(+), 1 deletion(-)
create mode 100644 clang/tools/clang-shlib/simple_version_script.map.in
diff --git a/clang/tools/clang-shlib/CMakeLists.txt
b/clang/tools/clang-shlib/CMakeLists.txt
index 298d3a9d18fec8..830f2b138ffa16 100644
--- a/clang/tools/clang-shlib/CMakeLists.txt
+++ b/clang/tools/clang-shlib/CMakeLists.txt
@@ -48,6 +48,14 @@ add_clang_library(clang-cpp
${_OBJECTS}
LINK_LIBS
${_DEPS})
+
+configure_file(simple_version_script.map.in simple_version_script.map)
+
+if (NOT LLVM_LINKER_IS_SOLARISLD AND NOT MINGW)
+ # Solaris ld does not accept global: *; so there is no way to version *all*
global symbols
+ target_link_options(clang-cpp PRIVATE
LINKER:--version-script,${CMAKE_CURRENT_BINARY_DIR}/simple_version_script.map)
+endif()
+
# Optimize function calls for default visibility definitions to avoid PLT and
# reduce dynamic relocations.
if (NOT APPLE AND NOT MINGW AND NOT LLVM_LINKER_IS_SOLARISLD_ILLUMOS)
diff --git a/clang/tools/clang-shlib/simple_version_script.map.in
b/clang/tools/clang-shlib/simple_version_script.map.in
new file mode 100644
index 00000000000000..cb2306d1f59682
--- /dev/null
+++ b/clang/tools/clang-shlib/simple_version_script.map.in
@@ -0,0 +1 @@
+@LLVM_SHLIB_SYMBOL_VERSION@ { global: *; };
diff --git a/llvm/CMakeLists.txt b/llvm/CMakeLists.txt
index cde4a999ea2e74..304197667dad6e 100644
--- a/llvm/CMakeLists.txt
+++ b/llvm/CMakeLists.txt
@@ -27,7 +27,7 @@ if (NOT PACKAGE_VERSION)
endif()
if(NOT DEFINED LLVM_SHLIB_SYMBOL_VERSION)
- # "Symbol version prefix for libLLVM.so"
+ # "Symbol version prefix for libLLVM.so and libclang-cpp.so"
set(LLVM_SHLIB_SYMBOL_VERSION
"LLVM_${LLVM_VERSION_MAJOR}.${LLVM_VERSION_MINOR}")
endif()
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