1 files changed, 57 insertions, 0 deletions
diff --git a/brp-llvm-compile-lto-elf b/brp-llvm-compile-lto-elf
new file mode 100644
index 0000000..9ef4d40
--- /dev/null
+++ b/brp-llvm-compile-lto-elf
@@ -0,0 +1,57 @@
+#!/usr/bin/bash -eu
+# From fedora:
+# https://src.fedoraproject.org/rpms/redhat-rpm-config
+# version 287
+
+
+if [ -z "$RPM_BUILD_ROOT" ] || [ "$RPM_BUILD_ROOT" = "/" ]; then
+	exit 0
+fi
+
+CLANG_FLAGS=$@
+NCPUS=${RPM_BUILD_NCPUS:-1}
+
+check_convert_bitcode () {
+  local file_name=$(realpath ${1})
+  local file_type=$(file ${file_name})
+
+  shift
+  CLANG_FLAGS="$@"
+
+  if [[ "${file_type}" == *"LLVM IR bitcode"* ]]; then
+    # Check the output of llvm-strings for the command line, which is in the LLVM bitcode because
+    # we pass -frecord-gcc-switches.
+    # Check for a line that has "-flto" after (or without) "-fno-lto".
+    llvm-strings ${file_name} | while read line ; do
+      flto=$(echo $line   | grep -o -b -e -flto     | tail -n 1 | cut -d : -f 1)
+      fnolto=$(echo $line | grep -o -b -e -fno-lto  | tail -n 1 | cut -d : -f 1)
+
+      if test -n "$flto" && { test -z "$fnolto" || test "$flto" -gt "$fnolto"; } ; then
+        echo "Compiling LLVM bitcode file ${file_name}."
+        clang ${CLANG_FLAGS} -fno-lto -Wno-unused-command-line-argument \
+          -x ir ${file_name} -c -o ${file_name}
+        break
+      fi
+      done
+  elif [[ "${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} ${CLANG_FLAGS}
+      echo "Repacking ${archived_file} into ${archive}."
+      ar r ${archive} ${archived_file}
+    done
+    popd
+  fi
+}
+
+echo "Checking for LLVM bitcode artifacts"
+export -f check_convert_bitcode
+# Deduplicate by device:inode to avoid processing hardlinks in parallel.
+find "$RPM_BUILD_ROOT" -type f -name "*.[ao]" -printf "%D:%i %p\n" | \
+  awk '!seen[$1]++' | cut -d" " -f2- | \
+  xargs -d"\n" -r -n1 -P$NCPUS sh -c "check_convert_bitcode \$@ $CLANG_FLAGS" ARG0