[libunwind] 21c24ae - [runtimes] Always build libc++, libc++abi and libunwind with -fPIC

[Louis Dionne via cfe-commits]

Author: Louis Dionne
Date: 2021-07-27T14:19:05-04:00
New Revision: 21c24ae9029a1fcd1c76b61b1c48b81b5c66c606

URL: https://github.com/llvm/llvm-project/commit/21c24ae9029a1fcd1c76b61b1c48b81b5c66c606
DIFF: https://github.com/llvm/llvm-project/commit/21c24ae9029a1fcd1c76b61b1c48b81b5c66c606.diff

LOG: [runtimes] Always build libc++, libc++abi and libunwind with -fPIC

Building the libraries with -fPIC ensures that we can link an executable
against the static libraries with -fPIE. Furthermore, there is apparently
basically no downside to building the libraries with position independent
code, since modern toolchains are sufficiently clever.

This commit enforces that we always build the runtime libraries with -fPIC.
This is another take on D104327, which instead makes the decision of whether
to build with -fPIC or not to the build script that drives the runtimes'
build.

Fixes http://llvm.org/PR43604.

Differential Revision: https://reviews.llvm.org/D104328

Added: 
    

Modified: 
    libcxx/src/CMakeLists.txt
    libcxxabi/src/CMakeLists.txt
    libunwind/src/CMakeLists.txt

Removed: 
    


################################################################################
diff  --git a/libcxx/src/CMakeLists.txt b/libcxx/src/CMakeLists.txt
index 87b71f7ba334b..f8c4d3e7df80b 100644
--- a/libcxx/src/CMakeLists.txt
+++ b/libcxx/src/CMakeLists.txt
@@ -198,6 +198,7 @@ if (LIBCXX_ENABLE_SHARED)
       VERSION       "${LIBCXX_ABI_VERSION}.0"
       SOVERSION     "${LIBCXX_ABI_VERSION}"
       DEFINE_SYMBOL ""
+      POSITION_INDEPENDENT_CODE ON
   )
   cxx_add_common_build_flags(cxx_shared)
   cxx_set_common_defines(cxx_shared)
@@ -272,6 +273,7 @@ if (LIBCXX_ENABLE_STATIC)
       COMPILE_FLAGS "${LIBCXX_COMPILE_FLAGS}"
       LINK_FLAGS    "${LIBCXX_LINK_FLAGS}"
       OUTPUT_NAME   "c++"
+      POSITION_INDEPENDENT_CODE ON
   )
   cxx_add_common_build_flags(cxx_static)
   cxx_set_common_defines(cxx_static)

diff  --git a/libcxxabi/src/CMakeLists.txt b/libcxxabi/src/CMakeLists.txt
index 889d751b2ef7d..f07d4334916ae 100644
--- a/libcxxabi/src/CMakeLists.txt
+++ b/libcxxabi/src/CMakeLists.txt
@@ -191,6 +191,7 @@ if (LIBCXXABI_ENABLE_SHARED)
       SOVERSION "1"
       VERSION "${LIBCXXABI_LIBRARY_VERSION}"
       DEFINE_SYMBOL ""
+      POSITION_INDEPENDENT_CODE ON
   )
 
   list(APPEND LIBCXXABI_BUILD_TARGETS "cxxabi_shared")
@@ -243,6 +244,7 @@ if (LIBCXXABI_ENABLE_STATIC)
       COMPILE_FLAGS "${LIBCXXABI_COMPILE_FLAGS}"
       LINK_FLAGS "${LIBCXXABI_LINK_FLAGS}"
       OUTPUT_NAME "c++abi"
+      POSITION_INDEPENDENT_CODE ON
     )
 
   if(LIBCXXABI_HERMETIC_STATIC_LIBRARY)

diff  --git a/libunwind/src/CMakeLists.txt b/libunwind/src/CMakeLists.txt
index 05d3e59c81fb8..093804fe4a2f9 100644
--- a/libunwind/src/CMakeLists.txt
+++ b/libunwind/src/CMakeLists.txt
@@ -141,6 +141,7 @@ if (LIBUNWIND_ENABLE_SHARED)
       OUTPUT_NAME "unwind"
       VERSION "1.0"
       SOVERSION "1"
+      POSITION_INDEPENDENT_CODE ON
   )
   list(APPEND LIBUNWIND_BUILD_TARGETS "unwind_shared")
   if (LIBUNWIND_INSTALL_SHARED_LIBRARY)
@@ -166,6 +167,7 @@ if (LIBUNWIND_ENABLE_STATIC)
       LINK_FLAGS "${LIBUNWIND_LINK_FLAGS}"
       LINKER_LANGUAGE C
       OUTPUT_NAME "unwind"
+      POSITION_INDEPENDENT_CODE ON
   )
 
   if(LIBUNWIND_HIDE_SYMBOLS)