From 391eca35086717a713c3f622a2e58ded465ce282 Mon Sep 17 00:00:00 2001
From: David Benoit <dbenoit@redhat.com>
Date: Wed, 10 Feb 2021 11:59:25 -0500
Subject: [PATCH] add brp-llvm-compile-lto-elf

---
 brp-llvm-compile-lto-elf | 47 ++++++++++++++++++++++++++++++++++++++++
 macros                   |  3 +++
 redhat-rpm-config.spec   | 12 +++++++++-
 3 files changed, 61 insertions(+), 1 deletion(-)
 create mode 100755 brp-llvm-compile-lto-elf

diff --git a/brp-llvm-compile-lto-elf b/brp-llvm-compile-lto-elf
new file mode 100755
index 0000000..19783fa
--- /dev/null
+++ b/brp-llvm-compile-lto-elf
@@ -0,0 +1,47 @@
+#!/usr/bin/bash -eu
+
+CLANG_FLAGS=$@
+
+if [ -z "$RPM_BUILD_ROOT" ] || [ "$RPM_BUILD_ROOT" = "/" ]; then
+	exit 0
+fi
+
+TMPDIR=`mktemp -d`
+
+check_convert_bitcode () {
+  local file_name=`realpath ${1}`
+  local file_type=`file ${file_name}`
+
+  if [[ "${file_type}" == *"LLVM IR bitcode"*  ]]; then
+    # check for an indication that the bitcode was
+    # compiled with -flto
+    llvm-bcanalyzer -dump ${file_name} | grep -xP '.*\-flto((?!-fno-lto).)*' 2>&1 > /dev/null
+    if [ $? -eq 0 ]; then
+      echo "Compiling LLVM bitcode file ${file_name}."
+      # create path to file in temp dir
+      # move file to temp dir with llvm .bc extension for clang
+      mkdir -p ${TMPDIR}/`dirname ${file_name}`
+      mv $file_name ${TMPDIR}/${file_name}.bc
+      clang -c ${CLANG_FLAGS} -fno-lto -Wno-unused-command-line-argument ${TMPDIR}/${file_name}.bc -o ${file_name}
+    fi
+  elif [[ "${file_type}" == *"current ar archive"*  ]]; then
+    echo "Unpacking ar archive ${file_name} to check for LLVM bitcode components."
+    # create archive stage for objects
+    local archive_stage=`mktemp -d`
+    local archive=${file_name}
+    pushd ${archive_stage}
+    ar x ${archive}
+    for archived_file in `find -not -type d`; do
+      check_convert_bitcode ${archived_file}
+      echo "Repacking ${archived_file} into ${archive}."
+      ar r ${archive} ${archived_file}
+    done
+    popd
+  fi
+}
+
+echo "Checking for LLVM bitcode artifacts"
+for i in `find $RPM_BUILD_ROOT -type f -name "*.[ao]"`; do
+  check_convert_bitcode ${i}
+done
+
diff --git a/macros b/macros
index f062f94..b946438 100644
--- a/macros
+++ b/macros
@@ -253,7 +253,10 @@ print(result)
 # __brp_mangle_shebangs_exclude_from_file - file from which to get files to ignore
 %__brp_mangle_shebangs /usr/lib/rpm/redhat/brp-mangle-shebangs %{?__brp_mangle_shebangs_exclude:--shebangs "%{?__brp_mangle_shebangs_exclude}"} %{?__brp_mangle_shebangs_exclude_file:--shebangs-from "%{__brp_mangle_shebangs_exclude_file}"} %{?__brp_mangle_shebangs_exclude_from:--files "%{?__brp_mangle_shebangs_exclude_from}"} %{?__brp_mangle_shebangs_exclude_from_file:--files-from "%{__brp_mangle_shebangs_exclude_from_file}"}
 
+%__brp_llvm_compile_lto_elf /usr/lib/rpm/redhat/brp-llvm-compile-lto-elf %{build_cflags} %{build_ldflags}
+
 %__os_install_post    \
+    %[ "%{toolchain}" == "clang" ? "%{?__brp_llvm_compile_lto_elf}" : "%{nil}" ] \
     %{?__brp_ldconfig} \
     %{?__brp_compress} \
     %{!?__debug_package:\
diff --git a/redhat-rpm-config.spec b/redhat-rpm-config.spec
index bc0910d..8752e3d 100644
--- a/redhat-rpm-config.spec
+++ b/redhat-rpm-config.spec
@@ -6,7 +6,7 @@
 
 Summary: Red Hat specific rpm configuration files
 Name: redhat-rpm-config
-Version: 182
+Version: 183
 Release: 1%{?dist}
 # No version specified.
 License: GPL+
@@ -57,6 +57,9 @@ Source202: brp-python-bytecompile
 # https://github.com/fedora-python/marshalparser
 Source203: brp-fix-pyc-reproducibility
 
+# for converting llvm LTO bitcode objects into ELF
+Source204: brp-llvm-compile-lto-elf
+
 # Dependency generator scripts (deprecated)
 Source300: find-provides
 Source301: find-provides.ksyms
@@ -124,6 +127,9 @@ Requires: %{_bindir}/grep
 Requires: %{_bindir}/sed
 Requires: %{_bindir}/xargs
 
+# for brp-llvm-compile-lto-elf
+Requires: (llvm if clang)
+
 # -fstack-clash-protection and -fcf-protection require GCC 8.
 Conflicts: gcc < 8.0.1-0.22
 
@@ -213,6 +219,10 @@ install -p -m 644 -t %{buildroot}%{_rpmluadir}/fedora/srpm forge.lua
 %{_rpmconfigdir}/macros.d/macros.kmp
 
 %changelog
+* Tue Apr  6 2021 David Benoit <dbenoit@redhat.com> - 183-1
+- BRP: LLVM Compile LTO Bitcode to ELF
+- Add Requires: (llvm if clang)
+
 * Mon Mar 22 2021 Lumír Balhar <lbalhar@redhat.com> - 182-1
 - Fix handling of files without newlines in brp-mangle-shebang