Merge pull request #166 from nathanchance/lto

driver: Disable LTO/CFI by default

Author: nathanchance

driver.sh

@@ -9,6 +9,7 @@ setup_variables() {
       "-c"|"--clean") cleanup=true ;;
       "-j"|"--jobs") shift; jobs=$1 ;;
       "-j"*) jobs=${1/-j} ;;
+      "--lto") disable_lto=false ;;
       "-h"|"--help")
         cat usage.txt
         exit 0 ;;
@@ -269,6 +270,8 @@ build_linux() {
     [[ $ARCH != "x86_64" ]] && cat ../configs/tt.config >> .config
     # Disable ftrace on arm32: https://github.com/ClangBuiltLinux/linux/issues/35
     [[ $ARCH == "arm" ]] && ./scripts/config -d CONFIG_FTRACE
+    # Disable LTO and CFI unless explicitly requested
+    ${disable_lto:=true} && ./scripts/config -d CONFIG_LTO -d CONFIG_LTO_CLANG
   fi
   # Make sure we build with CONFIG_DEBUG_SECTION_MISMATCH so that the
   # full warning gets printed and we can file and fix it properly.

usage.txt

@@ -42,3 +42,7 @@ Optional parameters:
   -j | --jobs
       Pass this value to make. The script will use all cores by default but
       this isn't always the best value.
+  --lto
+      By default, the script turns off LTO/CFI for quicker build times. If
+      your machine can handle the more intensive compile, pass this flag
+      to avoid attempting to disable it. This does not enable LTO explicitly.