build: Factor out vars.mk generation into a script

2 files changed, 83 insertions, 34 deletions

diff --git a/Makefile b/Makefile
index 0df7ce5..9117fe9 100644
--- a/Makefile
+++ b/Makefile
@@ -123,7 +123,7 @@ export UBSAN_CFLAGS= -fsanitize=undefined
 export TSAN_CPPFLAGS= -DBFS_USE_TARGET_CLONES=0
 export TSAN_CFLAGS= -fsanitize=thread
 
-SAN := ${ASAN}${LSAN}${MSAN}${TSAN}${UBSAN}
+export SAN=${ASAN}${LSAN}${MSAN}${TSAN}${UBSAN}
 export SAN_CFLAGS= -fno-sanitize-recover=all
 
 # MSAN and TSAN both need all code to be instrumented
@@ -212,39 +212,7 @@ config: ${MKS}
 # Saves the configurable variables
 ${GEN}/vars.mk:
 	@${XMKDIR} ${@D}
-	@printf 'PREFIX := %s\n' "$$XPREFIX" >$@
-	@printf 'MANDIR := %s\n' "$$XMANDIR" >>$@
-	@printf 'OS := %s\n' "$$XOS" >>$@
-	@printf 'ARCH := %s\n' "$$XARCH" >>$@
-	@printf 'CC := %s\n' "$$XCC" >>$@
-	@printf 'INSTALL := %s\n' "$$XINSTALL" >>$@
-	@printf 'MKDIR := %s\n' "$$XMKDIR" >>$@
-	@printf 'RM := %s\n' "$$XRM" >>$@
-	@printf '# BFS_CPPFLAGS\nCPPFLAGS := %s\n' "$$BFS_CPPFLAGS" >>$@
-	@test "${TSAN}" != y || printf '# TSAN\nCPPFLAGS += %s\n' "$$TSAN_CPPFLAGS" >>$@
-	@test "${LINT}" != y || printf '# LINT\nCPPFLAGS += %s\n' "$$LINT_CPPFLAGS" >>$@
-	@test "${RELEASE}" != y || printf '# RELEASE\nCPPFLAGS += %s\n' "$$RELEASE_CPPFLAGS" >>$@
-	@printf '# CPPFLAGS\nCPPFLAGS += %s\n' "$$XCPPFLAGS" >>$@
-	@printf '# EXTRA_CPPFLAGS\nCPPFLAGS += %s\n' "$$EXTRA_CPPFLAGS" >>$@
-	@printf '# BFS_CFLAGS\nCFLAGS := %s\n' "$$BFS_CFLAGS" >>$@
-	@test "${ASAN}" != y || printf '# ASAN\nCFLAGS += %s\n' "$$ASAN_CFLAGS" >>$@
-	@test "${LSAN}" != y || printf '# LSAN\nCFLAGS += %s\n' "$$LSAN_CFLAGS" >>$@
-	@test "${MSAN}" != y || printf '# MSAN\nCFLAGS += %s\n' "$$MSAN_CFLAGS" >>$@
-	@test "${TSAN}" != y || printf '# TSAN\nCFLAGS += %s\n' "$$TSAN_CFLAGS" >>$@
-	@test "${UBSAN}" != y || printf '# UBSAN\nCFLAGS += %s\n' "$$UBSAN_CFLAGS" >>$@
-	@case "${SAN}" in *y*) printf '# *SAN\nCFLAGS += %s\n' "$$SAN_CFLAGS" >>$@ ;; esac
-	@test "${GCOV}" != y || printf '# GCOV\nCFLAGS += %s\n' "$$GCOV_CFLAGS" >>$@
-	@test "${LINT}" != y || printf '# LINT\nCFLAGS += %s\n' "$$LINT_CFLAGS" >>$@
-	@test "${RELEASE}" != y || printf '# RELEASE\nCFLAGS += %s\n' "$$RELEASE_CFLAGS" >>$@
-	@printf '# CFLAGS\nCFLAGS += %s\n' "$$XCFLAGS" >>$@
-	@printf '# EXTRA_CFLAGS\nCFLAGS += %s\n' "$$EXTRA_CFLAGS" >>$@
-	@printf '# LDFLAGS\nLDFLAGS := %s\n' "$$XLDFLAGS" >>$@
-	@printf '# EXTRA_LDFLAGS\nLDFLAGS += %s\n' "$$EXTRA_LDFLAGS" >>$@
-	@printf '# LDLIBS\nLDLIBS := %s\n' "$$XLDLIBS" >>$@
-	@printf '# EXTRA_LDLIBS\nLDLIBS += %s\n' "$$EXTRA_LDLIBS" >>$@
-	@printf '# BFS_LDLIBS\nLDLIBS += %s\n' "$$BFS_LDLIBS" >>$@
-	@printf 'PKGS :=\n' >>$@
-	@case "${OS}-${SAN}" in FreeBSD-*y*) printf 'POSTLINK = elfctl -e +noaslr $$@\n' >>$@ ;; esac
+	@config/vars.sh >$@
 	@cat $@
 .PHONY: ${GEN}/vars.mk
 
diff --git a/config/vars.sh b/config/vars.sh
new file mode 100755
index 0000000..c0fb124
--- /dev/null
+++ b/config/vars.sh
@@ -0,0 +1,81 @@
+#!/usr/bin/env bash
+
+# Copyright © Tavian Barnes <tavianator@tavianator.com>
+# SPDX-License-Identifier: 0BSD
+
+# Writes the saved variables to gen/vars.mk
+
+set -eu
+
+print() {
+    NAME="$1"
+    OP="${2:-:=}"
+
+    if (($# >= 3)); then
+        printf '# %s\n' "${3#X}"
+        declare -n VAR="$3"
+        VALUE="${VAR:-}"
+    else
+        # Try X$NAME, $NAME, ""
+        local -n XVAR="X$NAME"
+        local -n VAR="$NAME"
+        VALUE="${XVAR:-${VAR:-}}"
+    fi
+
+    printf '%s %s %s\n' "$NAME" "$OP" "$VALUE"
+}
+
+cond_flags() {
+    local -n COND="$1"
+
+    if [[ "${COND:-}" == *y* ]]; then
+        print "$2" += "${1}_${2}"
+    fi
+}
+
+print PREFIX
+print MANDIR
+
+print OS
+print ARCH
+
+print CC
+print INSTALL
+print MKDIR
+print RM
+
+print CPPFLAGS := BFS_CPPFLAGS
+cond_flags TSAN CPPFLAGS
+cond_flags LINT CPPFLAGS
+cond_flags RELEASE CPPFLAGS
+print CPPFLAGS += XCPPFLAGS
+print CPPFLAGS += EXTRA_CPPFLAGS
+
+print CFLAGS := BFS_CFLAGS
+cond_flags ASAN CFLAGS
+cond_flags LSAN CFLAGS
+cond_flags MSAN CFLAGS
+cond_flags TSAN CFLAGS
+cond_flags UBSAN CFLAGS
+cond_flags SAN CFLAGS
+cond_flags GCOV CFLAGS
+cond_flags LINT CFLAGS
+cond_flags RELEASE CFLAGS
+print CFLAGS += XCFLAGS
+print CFLAGS += EXTRA_CFLAGS
+
+print LDFLAGS := XLDFLAGS
+print LDFLAGS += EXTRA_LDFLAGS
+
+print LDLIBS := XLDLIBS
+print LDLIBS += EXTRA_LDLIBS
+print LDLIBS += BFS_LDLIBS
+
+print PKGS
+
+# Disable ASLR on FreeBSD when sanitizers are enabled
+case "$XOS-$SAN" in
+    FreeBSD-*y*)
+        printf 'POSTLINK = elfctl -e +noaslr $$@\n'
+        ;;
+esac