Add support for building a musl-based toolchain

Musl is great for embedded projects since it doesn't have any
external runtime dependencies on static builds (glibc needs
libnss for gethostbyname etc), and produces much smaller binaries.
It's also needed for supporting Alpine Linux (the most common distro
used for containers).

This patch expects the latest riscv-musl repository to be cloned
inside the source dir (e.g. as a submodule like the rest). Currently
only riscv64 is supported (no multilib).

1 files changed, 150 insertions, 5 deletions

diff --git a/Makefile.in b/Makefile.in
index ccf1c82..f4d771c 100644
--- a/Makefile.in
+++ b/Makefile.in
@@ -53,6 +53,7 @@ endif
 make_tuple = riscv$(1)-unknown-$(2)
 LINUX_TUPLE  ?= $(call make_tuple,$(XLEN),linux-gnu)
 NEWLIB_TUPLE ?= $(call make_tuple,$(XLEN),elf)
+MUSL_TUPLE ?= $(call make_tuple,$(XLEN),linux-musl)
 
 CFLAGS_FOR_TARGET := $(CFLAGS_FOR_TARGET_EXTRA) @cmodel@
 CXXFLAGS_FOR_TARGET := $(CXXFLAGS_FOR_TARGET_EXTRA) @cmodel@
@@ -62,20 +63,27 @@ BINUTILS_TARGET_FLAGS := --with-expat=yes $(BINUTILS_TARGET_FLAGS_EXTRA)
 BINUTILS_NATIVE_FLAGS := $(BINUTILS_NATIVE_FLAGS_EXTRA)
 GDB_TARGET_FLAGS := --with-expat=yes $(GDB_TARGET_FLAGS_EXTRA)
 GDB_NATIVE_FLAGS := $(GDB_NATIVE_FLAGS_EXTRA)
+
 GLIBC_TARGET_FLAGS := $(GLIBC_TARGET_FLAGS_EXTRA)
 GLIBC_CC_FOR_TARGET ?= $(LINUX_TUPLE)-gcc
 GLIBC_CXX_FOR_TARGET ?= $(LINUX_TUPLE)-g++
 GLIBC_TARGET_BOARDS ?= $(shell echo "$(GLIBC_MULTILIB_NAMES)" | sed 's!\([a-z0-9]*\)-\([a-z0-9]*\)!riscv-sim/-march=\1/-mabi=\2/@cmodel@!g')
+
 NEWLIB_CC_FOR_TARGET ?= $(NEWLIB_TUPLE)-gcc
 NEWLIB_CXX_FOR_TARGET ?= $(NEWLIB_TUPLE)-g++
 NEWLIB_TARGET_BOARDS ?= $(shell echo "$(NEWLIB_MULTILIB_NAMES)" | sed 's!\([a-z0-9]*\)-\([a-z0-9]*\)!riscv-sim/-march=\1/-mabi=\2/@cmodel@!g')
 NEWLIB_NANO_TARGET_BOARDS ?= $(shell echo "$(NEWLIB_MULTILIB_NAMES)" | sed 's!\([a-z0-9]*\)-\([a-z0-9]*\)!riscv-sim-nano/-march=\1/-mabi=\2/@cmodel@!g')
 
+MUSL_TARGET_FLAGS := $(MUSL_TARGET_FLAGS_EXTRA)
+MUSL_CC_FOR_TARGET ?= $(MUSL_TUPLE)-gcc
+MUSL_CXX_FOR_TARGET ?= $(MUSL_TUPLE)-g++
+
 CONFIGURE_HOST   = @configure_host@
 
 all: @default_target@
 newlib: stamps/build-gcc-newlib-stage2
 linux: stamps/build-gcc-linux-stage2
+musl: stamps/build-gcc-musl-stage2
 ifeq (@enable_gdb@,--enable-gdb)
 newlib: stamps/build-gdb-newlib
 linux: stamps/build-gdb-linux
@@ -157,6 +165,17 @@ $(addprefix $(srcdir)/patches/,$(PACKAGES)): $(srcdir)/patches/%: src/%
 
 patches: $(addprefix $(srcdir)/patches/,$(PACKAGES))
 
+
+stamps/build-linux-headers:
+	mkdir -p $(SYSROOT)/usr/
+	cp -a $(srcdir)/linux-headers/include $(SYSROOT)/usr/
+	mkdir -p $(dir $@) && touch $@
+
+
+#
+# GLIBC
+#
+
 stamps/build-binutils-linux: $(srcdir)/riscv-binutils
 	rm -rf $@ $(notdir $@)
 	mkdir $(notdir $@)
@@ -203,11 +222,6 @@ stamps/build-gdb-linux: $(srcdir)/riscv-gdb
 	$(MAKE) -C $(notdir $@) install
 	mkdir -p $(dir $@) && touch $@
 
-stamps/build-linux-headers:
-	mkdir -p $(SYSROOT)/usr/
-	cp -a $(srcdir)/linux-headers/include $(SYSROOT)/usr/
-	mkdir -p $(dir $@) && touch $@
-
 stamps/build-glibc-linux-headers: $(srcdir)/riscv-glibc stamps/build-gcc-linux-stage1
 	rm -rf $@ $(notdir $@)
 	mkdir $(notdir $@)
@@ -372,6 +386,10 @@ stamps/build-gcc-linux-native: $(srcdir)/riscv-gcc stamps/build-gcc-linux-stage2
 	cp -a $(INSTALL_DIR)/$(LINUX_TUPLE)/lib* $(SYSROOT)
 	mkdir -p $(dir $@) && touch $@
 
+#
+# NEWLIB
+#
+
 stamps/build-binutils-newlib: $(srcdir)/riscv-binutils
 	rm -rf $@ $(notdir $@)
 	mkdir $(notdir $@)
@@ -535,6 +553,133 @@ stamps/build-gcc-newlib-stage2: $(srcdir)/riscv-gcc stamps/build-newlib \
 	$(MAKE) -C $(notdir $@) install
 	mkdir -p $(dir $@) && touch $@
 
+#
+# MUSL
+#
+
+stamps/build-binutils-musl: $(srcdir)/riscv-binutils
+	rm -rf $@ $(notdir $@)
+	mkdir $(notdir $@)
+# CC_FOR_TARGET is required for the ld testsuite.
+	cd $(notdir $@) && CC_FOR_TARGET=$(MUSL_CC_FOR_TARGET) $</configure \
+		--target=$(MUSL_TUPLE) \
+		$(CONFIGURE_HOST) \
+		--prefix=$(INSTALL_DIR) \
+		--with-sysroot=$(SYSROOT) \
+		$(MULTILIB_FLAGS) \
+		@with_guile@ \
+		--disable-werror \
+		--disable-nls \
+		$(BINUTILS_TARGET_FLAGS) \
+		--disable-gdb \
+		--disable-sim \
+		--disable-libdecnumber \
+		--disable-libreadline
+	$(MAKE) -C $(notdir $@)
+	$(MAKE) -C $(notdir $@) install
+	mkdir -p $(dir $@) && touch $@
+
+stamps/build-gcc-musl-stage1: $(srcdir)/riscv-gcc stamps/build-binutils-musl \
+                               stamps/build-linux-headers
+	if test -f $</contrib/download_prerequisites && test "@NEED_GCC_EXTERNAL_LIBRARIES@" == "true"; then cd $< && ./contrib/download_prerequisites; fi
+	rm -rf $@ $(notdir $@)
+	mkdir $(notdir $@)
+	cd $(notdir $@) && $</configure \
+		--target=$(MUSL_TUPLE) \
+		$(CONFIGURE_HOST) \
+		--prefix=$(INSTALL_DIR) \
+		--without-headers \
+		--disable-shared \
+		--disable-threads \
+		@with_system_zlib@ \
+		--enable-tls \
+		--enable-languages=c \
+		--disable-libatomic \
+		--disable-libmudflap \
+		--disable-libssp \
+		--disable-libquadmath \
+		--disable-libgomp \
+		--disable-nls \
+		--disable-bootstrap \
+		--src=$(gccsrcdir) \
+		$(GCC_CHECKING_FLAGS) \
+		--disable-multilib \
+		$(WITH_ABI) \
+		$(WITH_ARCH) \
+		CFLAGS_FOR_TARGET="-O2 $(CFLAGS_FOR_TARGET)" \
+		CXXFLAGS_FOR_TARGET="-O2 $(CXXFLAGS_FOR_TARGET)"
+	$(MAKE) -C $(notdir $@) inhibit-libc=true all-gcc
+	$(MAKE) -C $(notdir $@) inhibit-libc=true install-gcc
+	$(MAKE) -C $(notdir $@) inhibit-libc=true all-target-libgcc
+	$(MAKE) -C $(notdir $@) inhibit-libc=true install-target-libgcc
+	mkdir -p $(dir $@) && touch $@
+
+stamps/build-musl-linux-headers: $(srcdir)/riscv-musl stamps/build-gcc-musl-stage1
+	rm -rf $@ $(notdir $@)
+	mkdir $(notdir $@)
+	cd $(notdir $@) && CC="$(MUSL_CC_FOR_TARGET)" $</configure \
+		--host=$(MUSL_TUPLE) \
+		--prefix=$(SYSROOT)/usr \
+		--enable-shared \
+		--with-headers=$(srcdir)/linux-headers/include \
+		--disable-multilib \
+		--enable-kernel=3.0.0
+	$(MAKE) -C $(notdir $@) install-headers
+	mkdir -p $(dir $@) && touch $@
+
+stamps/build-musl-linux-riscv64: $(srcdir)/riscv-musl stamps/build-gcc-musl-stage1
+	rm -rf $@ $(notdir $@)
+	mkdir $(notdir $@)
+	cd $(notdir $@) && \
+		CC="$(MUSL_CC_FOR_TARGET) $($@_CFLAGS)" \
+		CXX="$(MUSL_CXX_FOR_TARGET) $($@_CFLAGS)" \
+		CFLAGS="$(CFLAGS_FOR_TARGET) -g -O2 $($@_CFLAGS)" \
+		CXXFLAGS="$(CXXFLAGS_FOR_TARGET) -g -O2 $($@_CFLAGS)" \
+		ASFLAGS="$(ASFLAGS_FOR_TARGET) $($@_CFLAGS)" \
+		$</configure \
+		--host=riscv64-unknown-linux-musl \
+		--prefix=$(SYSROOT)/usr \
+		--disable-werror \
+		--enable-shared \
+		--with-headers=$(srcdir)/linux-headers/include \
+		--enable-kernel=3.0.0 \
+		$(MUSL_TARGET_FLAGS)
+	$(MAKE) -C $(notdir $@)
+	+flock $(SYSROOT)/.lock $(MAKE) -C $(notdir $@) install install_root=$(SYSROOT)
+	mkdir -p $(dir $@) && touch $@
+
+stamps/build-gcc-musl-stage2: $(srcdir)/riscv-gcc stamps/build-musl-linux-riscv64 \
+                               stamps/build-musl-linux-headers
+	rm -rf $@ $(notdir $@)
+	mkdir $(notdir $@)
+	cd $(notdir $@) && $</configure \
+		--target=$(MUSL_TUPLE) \
+		$(CONFIGURE_HOST) \
+		--prefix=$(INSTALL_DIR) \
+		--with-sysroot=$(SYSROOT) \
+		@with_system_zlib@ \
+		--enable-shared \
+		--enable-tls \
+		--enable-languages=c,c++ \
+		--disable-libmudflap \
+		--disable-libssp \
+		--disable-libquadmath \
+		--disable-nls \
+		--disable-bootstrap \
+		--src=$(gccsrcdir) \
+		$(GCC_CHECKING_FLAGS) \
+		--disable-multilib \
+		$(WITH_ABI) \
+		$(WITH_ARCH) \
+		CFLAGS_FOR_TARGET="-O2 $(CFLAGS_FOR_TARGET)" \
+		CXXFLAGS_FOR_TARGET="-O2 $(CXXFLAGS_FOR_TARGET)"
+	$(MAKE) -C $(notdir $@)
+	$(MAKE) -C $(notdir $@) install
+	cp -a $(INSTALL_DIR)/$(MUSL_TUPLE)/lib* $(SYSROOT)
+	mkdir -p $(dir $@) && touch $@
+
+
+
 stamps/build-qemu: $(srcdir)/riscv-qemu
 	rm -rf $@ $(notdir $@)
 	mkdir $(notdir $@)