From 223f5481951047fa74a74d57819bb082aa462447 Mon Sep 17 00:00:00 2001
From: q66 <q66@chimera-linux.org>
Date: Sun, 14 Apr 2024 14:42:37 +0200
Subject: [PATCH 10/29] compiler-rt,libcxx(abi),libunwind: HACK: force -fno-lto

Also do -ftrivial-auto-var-init=unitialized for libunwind, as it appears
to break unwinding in strange ways with C++ on ppc64le, particularly with
LTO; this needs to be investigated properly though.

https://github.com/llvm/llvm-project/issues/76771
---
 compiler-rt/lib/builtins/CMakeLists.txt | 2 +-
 libcxx/CMakeLists.txt                   | 4 ++++
 libcxxabi/CMakeLists.txt                | 4 ++++
 libunwind/src/CMakeLists.txt            | 3 +++
 4 files changed, 12 insertions(+), 1 deletion(-)

diff --git a/compiler-rt/lib/builtins/CMakeLists.txt b/compiler-rt/lib/builtins/CMakeLists.txt
index f89cf87c7..51f59457a 100644
--- a/compiler-rt/lib/builtins/CMakeLists.txt
+++ b/compiler-rt/lib/builtins/CMakeLists.txt
@@ -756,7 +756,7 @@ if (APPLE)
   add_subdirectory(macho_embedded)
   darwin_add_builtin_libraries(${BUILTIN_SUPPORTED_OS})
 else ()
-  set(BUILTIN_CFLAGS "")
+  set(BUILTIN_CFLAGS "-fno-lto")
   add_security_warnings(BUILTIN_CFLAGS 0)
 
   if (COMPILER_RT_HAS_FCF_PROTECTION_FLAG)
diff --git a/libcxx/CMakeLists.txt b/libcxx/CMakeLists.txt
index abe12c280..17cf7c7ed 100644
--- a/libcxx/CMakeLists.txt
+++ b/libcxx/CMakeLists.txt
@@ -575,6 +575,10 @@ function(cxx_add_rtti_flags target)
       target_add_compile_flags_if_supported(${target} PUBLIC -fno-rtti)
     endif()
   endif()
+
+  target_add_compile_flags_if_supported(${target} PRIVATE "-fno-lto")
+  target_add_link_flags_if_supported(${target} PRIVATE "-fno-lto")
+  target_add_link_flags_if_supported(${target} PRIVATE "-rtlib=compiler-rt")
 endfunction()
 
 # Modules flags ===============================================================
diff --git a/libcxxabi/CMakeLists.txt b/libcxxabi/CMakeLists.txt
index 6dcfc51e5..1d03714f5 100644
--- a/libcxxabi/CMakeLists.txt
+++ b/libcxxabi/CMakeLists.txt
@@ -331,6 +331,10 @@ else()
   add_compile_flags_if_supported(-EHa-)
 endif()
 
+add_compile_flags("-fno-lto")
+add_link_flags("-fno-lto")
+add_link_flags("-rtlib=compiler-rt")
+
 # Assert
 string(TOUPPER "${CMAKE_BUILD_TYPE}" uppercase_CMAKE_BUILD_TYPE)
 if (LIBCXXABI_ENABLE_ASSERTIONS)
diff --git a/libunwind/src/CMakeLists.txt b/libunwind/src/CMakeLists.txt
index ecbd019bb..ec4108bd9 100644
--- a/libunwind/src/CMakeLists.txt
+++ b/libunwind/src/CMakeLists.txt
@@ -136,6 +136,9 @@ if (HAIKU)
   endif()
 endif ()
 
+add_compile_flags("-fno-lto -ftrivial-auto-var-init=uninitialized")
+add_link_flags("-fno-lto -ftrivial-auto-var-init=uninitialized")
+
 string(REPLACE ";" " " LIBUNWIND_COMPILE_FLAGS "${LIBUNWIND_COMPILE_FLAGS}")
 string(REPLACE ";" " " LIBUNWIND_CXX_FLAGS "${LIBUNWIND_CXX_FLAGS}")
 string(REPLACE ";" " " LIBUNWIND_C_FLAGS "${LIBUNWIND_C_FLAGS}")
-- 
2.49.0