build: Refactor configuration

We now use a recursive make invocation to do the work of `make config`.
The new implementation is also compatible with GNU make 3.81 found on
macOS.

1 files changed, 33 insertions, 336 deletions

diff --git a/Makefile b/Makefile
index 7cddc51..e9efef3 100644
--- a/Makefile
+++ b/Makefile
@@ -2,285 +2,27 @@
 # SPDX-License-Identifier: 0BSD
 
 # This Makefile implements the configuration and build steps for bfs.  It is
-# portable to both GNU make and the BSD make implementations (how that works
-# is documented below).  To build bfs, run
+# portable to both GNU make and most BSD make implementations.  To build bfs,
+# run
 #
 #     $ make config
 #     $ make
 
+# Utilities and GNU/BSD portability
+include config/prelude.mk
+
 # The default build target
 default: bfs
 .PHONY: default
 
-# BSD make will chdir into ${.OBJDIR} by default, unless we tell it not to
-.OBJDIR: .
-
-# We don't use any suffix rules
-.SUFFIXES:
-
-# GNU make has $^ for the full list of targets, while BSD make has $> and the
-# long-form ${.ALLSRC}.  We could write $^ $> to get them both, but that would
-# break if one of them implemented support for the other.  So instead, bring
-# BSD's ${.ALLSRC} to GNU.
-.ALLSRC ?= $^
-
-# GNU and BSD make have incompatible syntax for conditionals, but we can do a
-# lot with just recursive variable expansion.  Inspired by
-# https://github.com/wahern/autoguess
-TRUTHY,y := y
-TRUTHY,1 := y
-
-# Normalize ${V} to either "y" or ""
-IS_V := ${TRUTHY,${V}}
-
-# Suppress output unless V=1
-Q, := @
-Q  := ${Q,${IS_V}}
-
-# Show full commands with `make V=1`, otherwise short summaries
-MSG = @msg() { \
-          MSG="$$1"; \
-          shift; \
-          test "${IS_V}" || printf '%s\n' "$$MSG"; \
-          test "$${1:-}" || return 0; \
-          test "${IS_V}" && printf '%s\n' "$$*"; \
-          "$$@"; \
-      }; \
-      msg
-
-# Platform detection
-OS != uname
-ARCH != uname -m
-
-# For out-of-tree builds, e.g.
-#
-#     $ make config BUILDDIR=/path/to/build/dir
-#     $ make BUILDDIR=/path/to/build/dir
-BUILDDIR ?= .
-
-# Shorthand for build subdirectories
-BIN := ${BUILDDIR}/bin
-GEN := ${BUILDDIR}/gen
-OBJ := ${BUILDDIR}/obj
-
-# GNU make strips a leading ./ from target names, so do the same for BSD make
-BIN := ${BIN:./%=%}
-GEN := ${GEN:./%=%}
-OBJ := ${OBJ:./%=%}
-
-# Installation paths
-DESTDIR ?=
-PREFIX ?= /usr
-MANDIR ?= ${PREFIX}/share/man
-
-# Configurable executables; can be overridden with
-#
-#     $ make config CC=clang
-CC ?= cc
-INSTALL ?= install
-MKDIR ?= mkdir -p
-PKG_CONFIG ?= pkg-config
-RM ?= rm -f
-
-# Configurable flags
-
-CPPFLAGS ?=
-CFLAGS ?= \
-    -g \
-    -Wall \
-    -Wformat=2 \
-    -Werror=implicit \
-    -Wimplicit-fallthrough \
-    -Wmissing-declarations \
-    -Wshadow \
-    -Wsign-compare \
-    -Wstrict-prototypes
-LDFLAGS ?=
-LDLIBS ?=
-
-EXTRA_CPPFLAGS ?=
-EXTRA_CFLAGS ?=
-EXTRA_LDFLAGS ?=
-EXTRA_LDLIBS ?=
-
-GIT_VERSION != test -d .git && command -v git >/dev/null 2>&1 && git describe --always --dirty || echo 3.1.3
-VERSION ?= ${GIT_VERSION}
-
-# Immutable flags
-export BFS_CPPFLAGS= \
-    -D__EXTENSIONS__ \
-    -D_ATFILE_SOURCE \
-    -D_BSD_SOURCE \
-    -D_DARWIN_C_SOURCE \
-    -D_DEFAULT_SOURCE \
-    -D_GNU_SOURCE \
-    -D_LARGEFILE64_SOURCE \
-    -D_POSIX_PTHREAD_SEMANTICS \
-    -D_FILE_OFFSET_BITS=64 \
-    -D_TIME_BITS=64
-export BFS_CFLAGS= -std=c17 -pthread
-
-# Platform-specific system libraries
-LDLIBS,DragonFly := -lposix1e
-LDLIBS,Linux := -lrt
-LDLIBS,NetBSD := -lutil
-LDLIBS,SunOS := -lsocket -lnsl
-_BFS_LDLIBS := ${LDLIBS,${OS}}
-export BFS_LDLIBS=${_BFS_LDLIBS}
-
-# Build profiles
-ASAN ?= n
-LSAN ?= n
-MSAN ?= n
-TSAN ?= n
-UBSAN ?= n
-GCOV ?= n
-LINT ?= n
-RELEASE ?= n
-
-export ASAN_CFLAGS= -fsanitize=address
-export LSAN_CFLAGS= -fsanitize=leak
-export MSAN_CFLAGS= -fsanitize=memory -fsanitize-memory-track-origins
-export UBSAN_CFLAGS= -fsanitize=undefined
-
-# https://github.com/google/sanitizers/issues/342
-export TSAN_CPPFLAGS= -DBFS_USE_TARGET_CLONES=0
-export TSAN_CFLAGS= -fsanitize=thread
-
-export SAN=${ASAN}${LSAN}${MSAN}${TSAN}${UBSAN}
-export SAN_CFLAGS= -fno-sanitize-recover=all
-
-# MSAN and TSAN both need all code to be instrumented
-export NOLIBS= ${MSAN}${TSAN}
-
-# gcov only intercepts fork()/exec() with -std=gnu*
-export GCOV_CFLAGS= --coverage -std=gnu17
-
-export LINT_CPPFLAGS= -D_FORTIFY_SOURCE=3 -DBFS_LINT
-export LINT_CFLAGS= -Werror -O2
-
-export RELEASE_CPPFLAGS= -DNDEBUG
-export RELEASE_CFLAGS= -O3 -flto=auto
-
-# Save the new value of these variables, before they potentially get overridden
-# by `-include ${CONFIG}` below
-
-_XPREFIX := ${PREFIX}
-_XMANDIR := ${MANDIR}
-
-_XOS := ${OS}
-_XARCH := ${ARCH}
-
-_XCC := ${CC}
-_XINSTALL := ${INSTALL}
-_XMKDIR := ${MKDIR}
-_XRM := ${RM}
-
-_XCPPFLAGS := ${CPPFLAGS}
-_XCFLAGS := ${CFLAGS}
-_XLDFLAGS := ${LDFLAGS}
-_XLDLIBS := ${LDLIBS}
-
-# GNU make supports `export VAR`, but BSD make requires `export VAR=value`.
-# Sadly, GNU make gives a recursion error on `export VAR=${VAR}`.
-
-_BUILDDIR := ${BUILDDIR}
-_PKG_CONFIG := ${PKG_CONFIG}
-
-export BUILDDIR=${_BUILDDIR}
-export PKG_CONFIG=${_PKG_CONFIG}
-
-export XPREFIX=${_XPREFIX}
-export XMANDIR=${_XMANDIR}
-
-export XOS=${_XOS}
-export XARCH=${_XARCH}
-
-export XCC=${_XCC}
-export XINSTALL=${_XINSTALL}
-export XMKDIR=${_XMKDIR}
-export XRM=${_XRM}
-
-export XCPPFLAGS=${_XCPPFLAGS}
-export XCFLAGS=${_XCFLAGS}
-export XLDFLAGS=${_XLDFLAGS}
-export XLDLIBS=${_XLDLIBS}
-
-# The configuration file generated by `make config`
-CONFIG := ${GEN}/config.mk
+# Include the generated build config, if it exists
 -include ${CONFIG}
 
 ## Configuration phase (`make config`)
 
-# Makefile fragments generated by `make config`
-MKS := \
-    ${GEN}/vars.mk \
-    ${GEN}/deps.mk \
-    ${GEN}/objs.mk \
-    ${GEN}/pkgs.mk
-
-# cat a file if V=1
-VCAT,y := @cat
-VCAT,  := @:
-VCAT   := ${VCAT,${IS_V}}
-
 # The configuration goal itself
-config: ${MKS}
-	${MSG} "[ GEN] ${CONFIG}"
-	@printf 'include $${GEN}/%s\n' ${.ALLSRC:${GEN}/%=%} >${CONFIG}
-	${VCAT} ${CONFIG}
-.PHONY: config
-
-# Saves the configurable variables
-${GEN}/vars.mk:
-	@${XMKDIR} ${@D}
-	${MSG} "[ GEN] $@"
-	@config/vars.sh >$@
-	${VCAT} $@
-.PHONY: ${GEN}/vars.mk
-
-# Check for dependency generation support
-${GEN}/deps.mk: ${GEN}/vars.mk
-	${MSG} "[ GEN] $@"
-	@+${MAKE} -rs -f config/deps.mk TARGET=$@
-	${VCAT} $@
-	@printf -- '-include %s\n' ${OBJS:.o=.d} >>$@
-.PHONY: ${GEN}/deps.mk
-
-# Lists file.o: file.c dependencies
-${GEN}/objs.mk:
-	@${XMKDIR} ${@D}
-	${MSG} "[ GEN] $@"
-	@for obj in ${OBJS:${OBJ}/%.o=%}; do printf '$${OBJ}/%s.o: %s.c\n' "$$obj" "$$obj"; done >$@
-.PHONY: ${GEN}/objs.mk
-
-# External dependencies
-PKG_MKS := \
-    ${GEN}/libacl.mk \
-    ${GEN}/libcap.mk \
-    ${GEN}/libselinux.mk \
-    ${GEN}/liburing.mk \
-    ${GEN}/oniguruma.mk
-
-# Auto-detect dependencies and their build flags
-${GEN}/pkgs.mk: ${PKG_MKS}
-	${MSG} "[ GEN] $@"
-	@printf 'include $${GEN}/%s\n' ${.ALLSRC:${GEN}/%=%} >$@
-	@+${MAKE} -rs -f config/pkgs.mk TARGET=$@
-	${VCAT} $@
-.PHONY: ${GEN}/pkgs.mk
-
-# Auto-detect dependencies
-${PKG_MKS}: ${GEN}/vars.mk
-	@+${MAKE} -rs -f config/pkg.mk TARGET=$@
-	@if [ "${IS_V}" ]; then \
-	    cat $@; \
-	elif grep -q PKGS $@; then \
-	    printf '[ GEN] %-18s [y]\n' $@; \
-	else \
-	    printf '[ GEN] %-18s [n]\n' $@; \
-	fi
-.PHONY: ${PKG_MKS}
+config::
+	@+${MAKE} -sf config/config.mk
 
 # bfs used to have flag-like targets (`make release`, `make asan ubsan`, etc.).
 # Direct users to the new configuration system.
@@ -313,36 +55,6 @@ BINS := \
 all: ${BINS}
 .PHONY: all
 
-# All object files except the entry point
-LIBBFS := \
-    ${OBJ}/src/alloc.o \
-    ${OBJ}/src/bar.o \
-    ${OBJ}/src/bfstd.o \
-    ${OBJ}/src/bftw.o \
-    ${OBJ}/src/color.o \
-    ${OBJ}/src/ctx.o \
-    ${OBJ}/src/diag.o \
-    ${OBJ}/src/dir.o \
-    ${OBJ}/src/dstring.o \
-    ${OBJ}/src/eval.o \
-    ${OBJ}/src/exec.o \
-    ${OBJ}/src/expr.o \
-    ${OBJ}/src/fsade.o \
-    ${OBJ}/src/ioq.o \
-    ${OBJ}/src/mtab.o \
-    ${OBJ}/src/opt.o \
-    ${OBJ}/src/parse.o \
-    ${OBJ}/src/printf.o \
-    ${OBJ}/src/pwcache.o \
-    ${OBJ}/src/stat.o \
-    ${OBJ}/src/thread.o \
-    ${OBJ}/src/trie.o \
-    ${OBJ}/src/typo.o \
-    ${OBJ}/src/version.o \
-    ${OBJ}/src/xregex.o \
-    ${OBJ}/src/xspawn.o \
-    ${OBJ}/src/xtime.o
-
 # Group relevant flags together
 ALL_CFLAGS = ${CPPFLAGS} ${CFLAGS} ${DEPFLAGS}
 ALL_LDFLAGS = ${CFLAGS} ${LDFLAGS}
@@ -355,22 +67,6 @@ ${BINS}:
 	+${MSG} "[ LD ] $@" ${CC} ${ALL_LDFLAGS} ${.ALLSRC} ${LDLIBS} -o $@
 	${POSTLINK}
 
-# All object files
-OBJS := \
-    ${OBJ}/src/main.o \
-    ${OBJ}/tests/alloc.o \
-    ${OBJ}/tests/bfstd.o \
-    ${OBJ}/tests/bit.o \
-    ${OBJ}/tests/ioq.o \
-    ${OBJ}/tests/main.o \
-    ${OBJ}/tests/mksock.o \
-    ${OBJ}/tests/trie.o \
-    ${OBJ}/tests/xspawn.o \
-    ${OBJ}/tests/xspawnee.o \
-    ${OBJ}/tests/xtime.o \
-    ${OBJ}/tests/xtouch.o \
-    ${LIBBFS}
-
 # Get the .c file for a .o file
 CSRC = ${@:${OBJ}/%.o=%.c}
 
@@ -383,14 +79,20 @@ ${OBJS}: ${CONFIG}
 # Save the version number to this file, but only update VERSION if it changes
 ${GEN}/NEWVERSION::
 	@${MKDIR} ${@D}
-	@printf '%s\n' '${VERSION}' >$@
+	@if [ "$$VERSION" ]; then \
+	    printf '%s\n' "$$VERSION"; \
+	elif test -d .git && command -v git >/dev/null 2>&1; then \
+	    git describe --always --dirty; \
+	else \
+	    echo "3.1.3"; \
+	fi >$@
 
 ${GEN}/VERSION: ${GEN}/NEWVERSION
 	@test -e $@ && cmp -s $@ ${.ALLSRC} && rm ${.ALLSRC} || mv ${.ALLSRC} $@
 
 # Rebuild version.c whenever the version number changes
 ${OBJ}/src/version.o: ${GEN}/VERSION
-${OBJ}/src/version.o: CPPFLAGS := ${CPPFLAGS} -DBFS_VERSION='"${VERSION}"'
+${OBJ}/src/version.o: CPPFLAGS := ${CPPFLAGS} -DBFS_VERSION='"$$(cat ${GEN}/VERSION)"'
 
 ## Test phase (`make check`)
 
@@ -418,14 +120,7 @@ unit-tests: ${UTEST_BINS}
 .PHONY: unit-tests
 
 ${BIN}/tests/units: \
-    ${OBJ}/tests/alloc.o \
-    ${OBJ}/tests/bfstd.o \
-    ${OBJ}/tests/bit.o \
-    ${OBJ}/tests/ioq.o \
-    ${OBJ}/tests/main.o \
-    ${OBJ}/tests/trie.o \
-    ${OBJ}/tests/xspawn.o \
-    ${OBJ}/tests/xtime.o \
+    ${UNIT_OBJS} \
     ${LIBBFS}
 
 ${BIN}/tests/xspawnee: \
@@ -463,20 +158,20 @@ ${BIN}/tests/xtouch: \
     ${LIBBFS}
 
 # `make distcheck` configurations
-DISTCHECKS := distcheck-asan distcheck-tsan distcheck-release
-
-# Don't use msan on macOS
-IS_DARWIN,Darwin := y
-IS_DARWIN := ${IS_DARWIN,${OS}}
-DISTCHECK_MSAN, := distcheck-msan
-DISTCHECKS += ${DISTCHECK_MSAN,${IS_DARWIN}}
-
-# Only add a 32-bit build on 64-bit Linux
-DISTCHECK_M32,Linux,x86_64 := distcheck-m32
-DISTCHECKS += ${DISTCHECK_M32,${OS},${ARCH}}
+DISTCHECKS := \
+    distcheck-asan \
+    distcheck-msan \
+    distcheck-tsan \
+    distcheck-m32 \
+    distcheck-release
 
 # Test multiple configurations
-distcheck: ${DISTCHECKS}
+distcheck:
+	@+${MAKE} -s distcheck-asan
+	@+test "$$(uname)" = Darwin || ${MAKE} -s distcheck-msan
+	@+${MAKE} -s distcheck-tsan
+	@+test "$$(uname)-$$(uname -m)" != Linux-x86_64 || ${MAKE} -s distcheck-m32
+	@+${MAKE} -s distcheck-release
 .PHONY: distcheck
 
 # Per-distcheck configuration
@@ -530,9 +225,11 @@ check-install::
 
 # Clean all build products
 clean::
-	${RM} -r ${BIN} ${OBJ}
+	${MSG} "[ RM ] bin obj" \
+	    ${RM} -r ${BIN} ${OBJ}
 
 # Clean everything, including generated files
 distclean: clean
-	${RM} -r ${GEN} ${DISTCHECKS}
+	${MSG} "[ RM ] gen" \
+	    ${RM} -r ${GEN} ${DISTCHECKS}
 .PHONY: distclean