From c039e0465f0fc6636bc09a2874823ee0be6c54bb Mon Sep 17 00:00:00 2001
From: Sylvestre Ledru <sylvestre@debian.org>
Date: Sun, 1 Aug 2021 11:42:52 +0200
Subject: [PATCH] Build libunwind only on amd64 arm64 armhf i386 mips64el
 ppc64el ppc64 riscv64 sparc sparc64 Not supported on s390x for example

---
 debian/changelog |  8 ++++++++
 debian/control   |  4 ++--
 debian/rules     | 16 +++++++++++++---
 3 files changed, 23 insertions(+), 5 deletions(-)

diff --git a/debian/changelog b/debian/changelog
index dc8e5a8f..aa3ab28f 100644
--- a/debian/changelog
+++ b/debian/changelog
@@ -1,3 +1,11 @@
+llvm-toolchain-12 (1:12.0.1-3) unstable; urgency=medium
+
+  * Build libunwind only on amd64 arm64 armhf i386
+    mips64el ppc64el ppc64 riscv64 sparc sparc64
+    Not supported on s390x for example
+
+ -- Sylvestre Ledru <sylvestre@debian.org>  Sun, 01 Aug 2021 11:42:20 +0200
+
 llvm-toolchain-12 (1:12.0.1-2) unstable; urgency=medium
 
   * Generate libunwind-12 & libunwind-12-dev packages
diff --git a/debian/control b/debian/control
index 7f887bfe..15fd434d 100644
--- a/debian/control
+++ b/debian/control
@@ -718,7 +718,7 @@ Description: OpenCL C language implementation - development files
 
 Package: libunwind-12
 Section: libs
-Architecture: any
+Architecture: amd64 arm64 armhf i386 mips64el ppc64el ppc64 riscv64 sparc sparc64
 Multi-Arch: same
 Depends: ${shlibs:Depends},
  ${misc:Depends}
@@ -735,7 +735,7 @@ Description: production-quality unwinder
 
 Package: libunwind-12-dev
 Section: libdevel
-Architecture: any
+Architecture: amd64 arm64 armhf i386 mips64el ppc64el ppc64 riscv64 sparc sparc64
 Multi-Arch: same
 Depends:
  ${misc:Depends},
diff --git a/debian/rules b/debian/rules
index d3c73159..5771645b 100755
--- a/debian/rules
+++ b/debian/rules
@@ -1,7 +1,7 @@
 #!/usr/bin/make -f
 
 # polly, openmp & lldb aren't enabled for every platform
-PROJECTS = clang;clang-tools-extra;libcxx;libcxxabi;compiler-rt;lld;debuginfo-tests;libunwind
+PROJECTS = clang;clang-tools-extra;libcxx;libcxxabi;compiler-rt;lld;debuginfo-tests
 
 TARGET_BUILD	:= build-llvm
 TARGET_BUILD_STAGE2    := $(TARGET_BUILD)/tools/clang/stage2-bins
@@ -187,6 +187,14 @@ else
 #  CMAKE_EXTRA += -DLIBOMPTARGET_BUILD_NVPTX_BCLIB=ON -DLLVM_ENABLE_RUNTIMES=openmp
 endif
 
+# Enable libunwind (or not)
+LIBUNWIND_ENABLE=yes
+ifneq (,$(filter $(DEB_HOST_ARCH), amd64 arm64 armhf i386 mips64el ppc64el ppc64 riscv64 sparc sparc64))
+  LIBUNWIND_ENABLE=no
+else
+  PROJECTS+=;libunwind
+endif
+
 RUN_TEST=yes
 ifneq (,$(filter nocheck,$(DEB_BUILD_OPTIONS)))
 	RUN_TEST=no
@@ -623,8 +631,10 @@ override_dh_auto_install:
 	cd debian/tmp/usr/lib/llvm-$(LLVM_VERSION)/lib && rm -f libomp.so; \
 	ln -s libomp.so.$(SONAME_OPENMP) libomp.so
 
-	mkdir -p debian/tmp/usr/include/libunwind
-	cp -R libunwind/include/* debian/tmp/usr/include/libunwind/
+	if test "$(LIBUNWIND_ENABLE)" = yes; then \
+		mkdir -p debian/tmp/usr/include/libunwind; \
+		cp -R libunwind/include/* debian/tmp/usr/include/libunwind/; \
+	fi
 
 	if test "$(OPENMP_ENABLE)" = yes; then \
 		mkdir -p debian/tmp/usr/lib/llvm-$(LLVM_VERSION)/include/openmp; \