Use llvm-{objcopy,strip} when clang lld is used.

* Pass LLVM_{OBJCOPY,STRIP} to makefile rules.
* strip.sh is used only in soong-only mode.
  It will use llvm-strip and  and llvm-objcopy
  when --use-llvm-strip is given.
  Keep flags of strip.sh in alphabetic order.
* Tested build/soong/scripts/build-ndk-prebuilts.sh
  by adding "UseClangLld": true, to soong.variables file.

Bug: 80093681
Test: build/soong/scripts/build-ndk-prebuilts.sh
Change-Id: I612267304eea434c7a33cc086b27b577d5f64094

1 files changed, 57 insertions, 13 deletions

diff --git a/scripts/strip.sh b/scripts/strip.sh
index 318c7ad5..432582fc 100755
--- a/scripts/strip.sh
+++ b/scripts/strip.sh
@@ -17,15 +17,17 @@
 # Script to handle the various ways soong may need to strip binaries
 # Inputs:
 #  Environment:
+#   CLANG_BIN: path to the clang bin directory
 #   CROSS_COMPILE: prefix added to readelf, objcopy tools
 #   XZ: path to the xz binary
 #  Arguments:
 #   -i ${file}: input file (required)
 #   -o ${file}: output file (required)
 #   -d ${file}: deps file (required)
-#   --keep-symbols
-#   --keep-mini-debug-info
 #   --add-gnu-debuglink
+#   --keep-mini-debug-info
+#   --keep-symbols
+#   --use-llvm-strip
 
 OPTSTRING=d:i:o:-:
 
@@ -33,25 +35,52 @@ usage() {
     cat <<EOF
 Usage: strip.sh [options] -i in-file -o out-file -d deps-file
 Options:
-        --keep-symbols          Keep symbols in out-file
-        --keep-mini-debug-info  Keep compressed debug info in out-file
         --add-gnu-debuglink     Add a gnu-debuglink section to out-file
+        --keep-mini-debug-info  Keep compressed debug info in out-file
+        --keep-symbols          Keep symbols in out-file
+        --use-llvm-strip        Use llvm-{strip,objcopy} instead of strip/objcopy
 EOF
     exit 1
 }
 
+# With --use-llvm-strip, GNU strip is replaced with llvm-strip to work around
+# old GNU strip bug on lld output files, b/80093681.
+# Similary, calls to objcopy are replaced with llvm-objcopy,
+# with some exceptions.
+
 do_strip() {
-    "${CROSS_COMPILE}strip" --strip-all "${infile}" -o "${outfile}.tmp"
+    # ${CROSS_COMPILE}strip --strip-all does not strip .ARM.attributes,
+    # so we tell llvm-strip to keep it too.
+    if [ ! -z "${use_llvm_strip}" ]; then
+        "${CLANG_BIN}/llvm-strip" --strip-all -keep=.ARM.attributes "${infile}" "${outfile}.tmp"
+    else
+        "${CROSS_COMPILE}strip" --strip-all "${infile}" -o "${outfile}.tmp"
+    fi
 }
 
 do_strip_keep_symbols() {
-    "${CROSS_COMPILE}objcopy" "${infile}" "${outfile}.tmp" \
-	`"${CROSS_COMPILE}readelf" -S "${infile}" | awk '/.debug_/ {print "-R " $2}' | xargs`
+    # Maybe we should replace this objcopy with llvm-objcopy, but
+    # we have not found a use case that is broken by objcopy yet.
+    REMOVE_SECTIONS=`"${CROSS_COMPILE}readelf" -S "${infile}" | awk '/.debug_/ {print "--remove-section " $2}' | xargs`
+    if [ ! -z "${use_llvm_strip}" ]; then
+        "${CROSS_COMPILE}objcopy" "${infile}" "${outfile}.tmp" ${REMOVE_SECTIONS}
+    else
+        "${CLANG_BIN}/llvm-objcopy" "${infile}" "${outfile}.tmp" ${REMOVE_SECTIONS}
+    fi
 }
 
 do_strip_keep_mini_debug_info() {
     rm -f "${outfile}.dynsyms" "${outfile}.funcsyms" "${outfile}.keep_symbols" "${outfile}.debug" "${outfile}.mini_debuginfo" "${outfile}.mini_debuginfo.xz"
-    if "${CROSS_COMPILE}strip" --strip-all -R .comment "${infile}" -o "${outfile}.tmp"; then
+    if [ ! -z "${use_llvm_strip}" ]; then
+        "${CLANG_BIN}/llvm-strip" --strip-all -keep=.ARM.attributes -remove-section=.comment "${infile}" "${outfile}.tmp"
+    else
+        "${CROSS_COMPILE}strip" --strip-all -R .comment "${infile}" -o "${outfile}.tmp"
+    fi
+    if [ "$?" == "0" ]; then
+        # Current prebult llvm-objcopy does not support the following flags:
+        #    --only-keep-debug --rename-section --keep-symbols
+        # For the following use cases, ${CROSS_COMPILE}objcopy does fine with lld linked files,
+        # except the --add-section flag.
         "${CROSS_COMPILE}objcopy" --only-keep-debug "${infile}" "${outfile}.debug"
         "${CROSS_COMPILE}nm" -D "${infile}" --format=posix --defined-only | awk '{ print $$1 }' | sort >"${outfile}.dynsyms"
         "${CROSS_COMPILE}nm" "${infile}" --format=posix --defined-only | awk '{ if ($$2 == "T" || $$2 == "t" || $$2 == "D") print $$1 }' | sort > "${outfile}.funcsyms"
@@ -61,14 +90,22 @@ do_strip_keep_mini_debug_info() {
         "${CROSS_COMPILE}objcopy" -S --remove-section .gdb_index --remove-section .comment --keep-symbols="${outfile}.keep_symbols" "${outfile}.mini_debuginfo"
         "${CROSS_COMPILE}objcopy" --rename-section saved_debug_frame=.debug_frame "${outfile}.mini_debuginfo"
         "${XZ}" "${outfile}.mini_debuginfo"
-        "${CROSS_COMPILE}objcopy" --add-section .gnu_debugdata="${outfile}.mini_debuginfo.xz" "${outfile}.tmp"
+        if [ ! -z "${use_llvm_strip}" ]; then
+            "${CLANG_BIN}/llvm-objcopy" --add-section .gnu_debugdata="${outfile}.mini_debuginfo.xz" "${outfile}.tmp"
+        else
+            "${CROSS_COMPILE}objcopy" --add-section .gnu_debugdata="${outfile}.mini_debuginfo.xz" "${outfile}.tmp"
+        fi
     else
         cp -f "${infile}" "${outfile}.tmp"
     fi
 }
 
 do_add_gnu_debuglink() {
-    "${CROSS_COMPILE}objcopy" --add-gnu-debuglink="${infile}" "${outfile}.tmp"
+    if [ ! -z "${use_llvm_strip}" ]; then
+        "${CLANG_BIN}/llvm-objcopy" --add-gnu-debuglink="${infile}" "${outfile}.tmp"
+    else
+        "${CROSS_COMPILE}objcopy" --add-gnu-debuglink="${infile}" "${outfile}.tmp"
+    fi
 }
 
 while getopts $OPTSTRING opt; do
@@ -78,9 +115,10 @@ while getopts $OPTSTRING opt; do
 	o) outfile="${OPTARG}" ;;
 	-)
 	    case "${OPTARG}" in
-		keep-symbols) keep_symbols=true ;;
-		keep-mini-debug-info) keep_mini_debug_info=true ;;
 		add-gnu-debuglink) add_gnu_debuglink=true ;;
+		keep-mini-debug-info) keep_mini_debug_info=true ;;
+		keep-symbols) keep_symbols=true ;;
+		use-llvm-strip) use_llvm_strip=true ;;
 		*) echo "Unknown option --${OPTARG}"; usage ;;
 	    esac;;
 	?) usage ;;
@@ -130,12 +168,18 @@ fi
 rm -f "${outfile}"
 mv "${outfile}.tmp" "${outfile}"
 
+if [ ! -z "${use_llvm_strip}" ]; then
+  USED_STRIP_OBJCOPY="${CLANG_BIN}/llvm-strip ${CLANG_BIN}/llvm-objcopy"
+else
+  USED_STRIP_OBJCOPY="${CROSS_COMPILE}strip"
+fi
+
 cat <<EOF > "${depsfile}"
 ${outfile}: \
   ${infile} \
   ${CROSS_COMPILE}nm \
   ${CROSS_COMPILE}objcopy \
   ${CROSS_COMPILE}readelf \
-  ${CROSS_COMPILE}strip
+  ${USED_STRIP_OBJCOPY}
 
 EOF