Turn libffi into a Haskell package

1 files changed, 61 insertions, 5 deletions

diff --git a/libffi/Makefile b/libffi/Makefile
index f76c16d17c..a85372dea6 100644
--- a/libffi/Makefile
+++ b/libffi/Makefile
@@ -1,10 +1,31 @@
 
 TOP=..
+DONT_WANT_STD_GHCI_LIB_RULE=YES
+DONT_WANT_STD_LIBRARY=YES
 
 include $(TOP)/mk/boilerplate.mk
 
+# We package libffi as Haskell package for two reasons: 
+
+# 1) GHC uses different names for shared and static libs, so it can
+#    choose the lib variant to link with on its own. With regular
+#    libtool styled shared lib names, the linker would interfer and
+#    link against the shared lib variant even when GHC runs in -static
+#    mode.
+# 2) The first issue isn't a problem when a shared lib of libffi would
+#    be installed in system locations, but we do not assume that. So,
+#    when running in -dynamic mode, we must either install libffi to
+#    system locations ourselves, or we must add its location to
+#    respective environment variable, (DY)LD_LIBRARY_PATH etc...before
+#    we call dynamically linked binaries. Especially, the latter is
+#    necessary as GHC calls binary it produced before its installation
+#    phase. However, both mechanism, installing to system locations or
+#    modifying (DY)LD_LIBRARY_PATH, are already in place for Haskell
+#    packages so with packaging libffi as Haskell package we reuse
+#    them naturally.
+
+PACKAGE=ffi
 # -----------------------------------------------------------------------------
-# This Makefile is copied from the one we use for GMP in ../gmp.
 #
 # We use libffi's own configuration stuff.
 
@@ -50,6 +71,8 @@ DYNAMIC_PROG =
 DYNAMIC_LIBS = libffi.so libffi.so.5 libffi.so.5.0.5
 endif
 
+HS_DYN_LIB_NAME=libHSffi-ghc$(ProjectVersion)$(soext)
+
 ifeq "$(BuildSharedLibs)" "YES"
 EnableShared=yes
 else
@@ -68,7 +91,7 @@ install all :: $(INSTALL_HEADERS) $(INSTALL_LIBS) $(INSTALL_PROGS)
 # will use cygwin symbolic linkks which cannot be read by mingw gcc.
 # The same trick is played by the GMP build in ../gmp.
 
-stamp.ffi:
+stamp.ffi.configure:
 	$(RM) -rf $(LIBFFI_DIR) build
 	$(TAR) -zxf $(LIBFFI_TARBALL)
 	mv $(LIBFFI_DIR) build
@@ -81,17 +104,50 @@ stamp.ffi:
 		  --enable-static=yes \
 	          --enable-shared=$(EnableShared) \
 		  --host=$(PLATFORM) --build=$(PLATFORM)
+
+	# libffi.so needs to be built with the correct soname.
+	# NOTE: this builds libffi_convience.so with the incorrect
+	# soname, but we don't need that anyway!
+	sed -i -e s/soname_spec=.*/soname_spec="$(HS_DYN_LIB_NAME)"/ build/libtool
 	touch $@
 
-ffi.h: stamp.ffi
+ffi.h: stamp.ffi.configure
 	$(CP) build/include/ffi.h .
 
-$(STATIC_LIB) $(DYNAMIC_LIBS) $(DYNAMIC_PROG) : stamp.ffi
+stamp.ffi.build: stamp.ffi.configure
 	$(MAKE) -C build MAKEFLAGS=
 	(cd build; ./libtool --mode=install cp libffi.la $(FPTOOLS_TOP_ABS)/libffi)
+	touch $@
+
+$(STATIC_LIB) $(DYNAMIC_LIBS) $(DYNAMIC_PROG): stamp.ffi.build
+
+libHSffi.a libHSffi_p.a: $(STATIC_LIB)
+	cp $(STATIC_LIB) $@
+
+all :: libHSffi.a libHSffi_p.a
+
+# The GHCi import lib isn't needed as compiler/ghci/Linker.lhs + rts/Linker.c
+# link the interpreted references to FFI to the compiled FFI.
+# Instead of adding libffi to the list preloaded packages (see
+# compiler/ghci/Linker.lhs:emptyPLS) we generate an empty HSffi.o
+
+HSffi.o: libHSffi.a
+	ld -r -o HSffi.o /dev/null # this is intentional
+#	$(RM) -fr unpack
+#	(mkdir unpack; cd unpack; ar x ../libHSffi.a; ld -r -o ../HSffi.o *.o)
+#	$(RM) -fr unpack
+
+all :: HSffi.o
+
+ifeq "$(BuildSharedLibs)" "YES"
+$(HS_DYN_LIB_NAME): $(DYNAMIC_LIBS)
+	cp $(word 1,$(DYNAMIC_LIBS)) $(HS_DYN_LIB_NAME)
+
+all :: $(HS_DYN_LIB_NAME)
+endif
 
 clean distclean maintainer-clean ::
-	$(RM) -f stamp.ffi ffi.h
+	$(RM) -f stamp.ffi.configure stamp.ffi.build ffi.h
 	$(RM) -f libffi.a libffi.la $(DYNAMIC_PROG) $(DYNAMIC_LIBS) $(ORIG_DYNAMIC_LIBS)
 	$(RM) -rf build