Makefile: detect compiler and enable more warnings in DEVELOPER=1

[thirdparty/git.git] / detect-compiler

diff --git a/detect-compiler b/detect-compiler
new file mode 100755 (executable)
index 0000000..70b7544
--- /dev/null
+++ b/detect-compiler
@@ -0,0 +1,53 @@
+#!/bin/sh
+#
+# Probe the compiler for vintage, version, etc. This is used for setting
+# optional make knobs under the DEVELOPER knob.
+
+CC="$*"
+
+# we get something like (this is at least true for gcc and clang)
+#
+# FreeBSD clang version 3.4.1 (tags/RELEASE...)
+get_version_line() {
+       $CC -v 2>&1 | grep ' version '
+}
+
+get_family() {
+       get_version_line | sed 's/^\(.*\) version [0-9][^ ]* .*/\1/'
+}
+
+get_version() {
+       get_version_line | sed 's/^.* version \([0-9][^ ]*\) .*/\1/'
+}
+
+print_flags() {
+       family=$1
+       version=$(get_version | cut -f 1 -d .)
+
+       # Print a feature flag not only for the current version, but also
+       # for any prior versions we encompass. This avoids needing to do
+       # numeric comparisons in make, which are awkward.
+       while test "$version" -gt 0
+       do
+               echo $family$version
+               version=$((version - 1))
+       done
+}
+
+case "$(get_family)" in
+gcc)
+       print_flags gcc
+       ;;
+clang)
+       print_flags clang
+       ;;
+"FreeBSD clang")
+       print_flags clang
+       ;;
+"Apple LLVM")
+       print_flags clang
+       ;;
+*)
+       : unknown compiler family
+       ;;
+esac