From 1012fe8a5459c7227791e4f14714846af249f094 Mon Sep 17 00:00:00 2001
From: Bob Haarman <llvm@inglorion.net>
Date: Wed, 22 Mar 2017 17:25:49 +0000
Subject: [PATCH] [compiler-rt] build compiler-rt runtimes without LTO

Summary: Currently, we build the compiler-rt runtimes with link-time optimization if LTO is configured for the LLVM project. This will break external programs that don't invoke the linker in such a way that it supports LLVM's LTO. To avoid this, this change causes the compiler-rt runtimes to be compiled with -fno-lto. This also makes the check-profile tests work on systems when doing a lld LTO build on a system where the system linker does not support LLVM LTO.

Reviewers: rnk, davidxl

Reviewed By: davidxl

Subscribers: dberris, mgorny, llvm-commits, mehdi_amini

Differential Revision: https://reviews.llvm.org/D31218

llvm-svn: 298525
---
 compiler-rt/cmake/Modules/AddCompilerRT.cmake | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/compiler-rt/cmake/Modules/AddCompilerRT.cmake b/compiler-rt/cmake/Modules/AddCompilerRT.cmake
index d4533e6..b64eb42 100644
--- a/compiler-rt/cmake/Modules/AddCompilerRT.cmake
+++ b/compiler-rt/cmake/Modules/AddCompilerRT.cmake
@@ -110,6 +110,13 @@ function(add_compiler_rt_runtime name type)
     "OS;ARCHS;SOURCES;CFLAGS;LINK_FLAGS;DEFS;LINK_LIBS;OBJECT_LIBS"
     ${ARGN})
   set(libnames)
+  # Until we support this some other way, build compiler-rt runtime without LTO
+  # to allow non-LTO projects to link with it.
+  if(COMPILER_RT_HAS_FNO_LTO_FLAG)
+    set(NO_LTO_FLAGS "-fno-lto")
+  else()
+    set(NO_LTO_FLAGS "")
+  endif()
   if(APPLE)
     foreach(os ${LIB_OS})
       if(type STREQUAL "STATIC")
@@ -121,7 +128,7 @@ function(add_compiler_rt_runtime name type)
       list_intersect(LIB_ARCHS_${libname} DARWIN_${os}_ARCHS LIB_ARCHS)
       if(LIB_ARCHS_${libname})
         list(APPEND libnames ${libname})
-        set(extra_cflags_${libname} ${DARWIN_${os}_CFLAGS} ${LIB_CFLAGS})
+        set(extra_cflags_${libname} ${DARWIN_${os}_CFLAGS} ${NO_LTO_FLAGS} ${LIB_CFLAGS})
         set(output_name_${libname} ${libname}${COMPILER_RT_OS_SUFFIX})
         set(sources_${libname} ${LIB_SOURCES})
         format_object_libs(sources_${libname} ${os} ${LIB_OBJECT_LIBS})
@@ -149,7 +156,7 @@ function(add_compiler_rt_runtime name type)
       set(sources_${libname} ${LIB_SOURCES})
       format_object_libs(sources_${libname} ${arch} ${LIB_OBJECT_LIBS})
       set(libnames ${libnames} ${libname})
-      set(extra_cflags_${libname} ${TARGET_${arch}_CFLAGS} ${LIB_CFLAGS})
+      set(extra_cflags_${libname} ${TARGET_${arch}_CFLAGS} ${NO_LTO_FLAGS} ${LIB_CFLAGS})
     endforeach()
   endif()
 
-- 
2.7.4