sys-libs/compiler-rt: Backport crt*.o fix

Closes: https://bugs.gentoo.org/698086
Signed-off-by: Michał Górny <mgorny@gentoo.org>

1 files changed, 41 insertions, 0 deletions

diff --git a/sys-libs/compiler-rt/files/9.0.0/0001-compiler-rt-crt-make-test-case-nontrivial-in-check_c.patch b/sys-libs/compiler-rt/files/9.0.0/0001-compiler-rt-crt-make-test-case-nontrivial-in-check_c.patch
new file mode 100644
index 000000000000..ccae96cad98a
--- /dev/null
+++ b/sys-libs/compiler-rt/files/9.0.0/0001-compiler-rt-crt-make-test-case-nontrivial-in-check_c.patch
@@ -0,0 +1,41 @@
+From 155a43edb0c161bb5122ad4eeee991b43a0278bc Mon Sep 17 00:00:00 2001
+From: Jian Cai <caij2003@gmail.com>
+Date: Mon, 16 Sep 2019 21:47:47 +0000
+Subject: [PATCH] [compiler-rt][crt]  make test case nontrivial in
+ check_cxx_section_exists
+
+Summary:
+.init_array gets optimized away when building with -O2 and as a result,
+check_cxx_section_exists failed to pass -DCOMPILER_RT_HAS_INITFINI_ARRAY
+when building crtbegin.o and crtend.o, which causes binaries linked with
+them encounter segmentation fault. See https://crbug.com/855759 for
+details. This change prevents .init_array section to be optimized away
+even with -O2 or higher optimization level.
+
+Subscribers: dberris, mgorny, #sanitizers, llvm-commits
+
+Tags: #sanitizers, #llvm
+
+Differential Revision: https://reviews.llvm.org/D67628
+
+llvm-svn: 372038
+---
+ lib/crt/CMakeLists.txt | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/lib/crt/CMakeLists.txt b/lib/crt/CMakeLists.txt
+index 34c368f7ca4..90e94b93db4 100644
+--- a/lib/crt/CMakeLists.txt
++++ b/lib/crt/CMakeLists.txt
+@@ -70,7 +70,7 @@ function(check_cxx_section_exists section output)
+ endfunction()
+ 
+ check_cxx_section_exists(".init_array" COMPILER_RT_HAS_INITFINI_ARRAY
+-  SOURCE "__attribute__((constructor)) void f() {}\nint main() { return 0; }\n")
++  SOURCE "volatile int x;\n__attribute__((constructor)) void f() {x = 0;}\nint main() { return 0; }\n")
+ 
+ append_list_if(COMPILER_RT_HAS_STD_C11_FLAG -std=c11 CRT_CFLAGS)
+ append_list_if(COMPILER_RT_HAS_INITFINI_ARRAY -DCRT_HAS_INITFINI_ARRAY CRT_CFLAGS)
+-- 
+2.23.0
+