Import libffi-3.0.4, and use it to provide FFI support in GHCi

This replaces the hand-rolled architecture-specific FFI support in
GHCi with the standard libffi as used in GCJ, Python and other
projects.  I've bundled the complete libffi-3.0.4 tarball in the
source tree in the same way as we do for GMP, the difference being
that we always build and install our own libffi regardless of whether
there's one on the system (it's small, and we don't want
dependency/versioning headaches).

In particular this means that unregisterised builds will now have a
fully working GHCi including FFI out of the box, provided libffi
supports the platform.

There is also code in the RTS to use libffi in place of
rts/Adjustor.c, but it is currently not enabled if we already have
support in Adjustor.c for the current platform.  We need to assess the
performance impact before using libffi here too (in GHCi we don't care
too much about performance).

2 files changed, 124 insertions, 0 deletions

diff --git a/libffi/Makefile b/libffi/Makefile
new file mode 100644
index 0000000000..3a7cb693f7
--- /dev/null
+++ b/libffi/Makefile
@@ -0,0 +1,124 @@
+
+TOP=..
+
+include $(TOP)/mk/boilerplate.mk
+
+# -----------------------------------------------------------------------------
+# This Makefile is copied from the one we use for GMP in ../gmp.
+#
+# We use libffi's own configuration stuff.
+
+PLATFORM := $(shell echo $(HOSTPLATFORM) | sed 's/i[567]86/i486/g')
+
+# 2007-09-26
+#     set -o igncr 
+# is not a valid command on non-Cygwin-systems.
+# Let it fail silently instead of aborting the build.
+#
+# 2007-07-05
+# We do
+#     set -o igncr; export SHELLOPTS
+# here as otherwise checking the size of limbs
+# makes the build fall over on Cygwin. See the thread
+# http://www.cygwin.com/ml/cygwin/2006-12/msg00011.html
+# for more details.
+
+# 2007-07-05
+# Passing
+#     as_ln_s='cp -p'
+# isn't sufficient to stop cygwin using symlinks the mingw gcc can't
+# follow, as it isn't used consistently. Instead we put an ln.bat in
+# path that always fails.
+
+LIBFFI_TARBALL := $(firstword $(wildcard libffi*.tar.gz))
+LIBFFI_DIR := $(subst .tar.gz,,$(LIBFFI_TARBALL))
+
+ifeq "$(findstring dyn, $(GhcRTSWays))" "dyn"
+BUILD_SHARED=yes
+else
+BUILD_SHARED=no
+endif
+
+boot :: stamp.ffi.static
+BINDIST_STAMPS = stamp.ffi.static
+INSTALL_HEADERS += ffi.h
+INSTALL_LIBS += libffi.a
+
+ifeq "$(BUILD_SHARED)" "yes"
+boot :: stamp.ffi.shared
+BINDIST_STAMPS += stamp.ffi.shared
+INSTALL_LIBS += libffi.dll.a
+INSTALL_PROGS += libffi-3.dll
+endif
+
+install all :: $(INSTALL_HEADERS) $(INSTALL_LIBS) $(INSTALL_PROGS)
+
+stamp.ffi.static:
+	$(RM) -rf $(LIBFFI_DIR) build
+	$(TAR) -zxf $(LIBFFI_TARBALL)
+	mv $(LIBFFI_DIR) build
+#	chmod +x ln
+	(set -o igncr 2>/dev/null) && set -o igncr; export SHELLOPTS; \
+	    PATH=`pwd`:$$PATH; \
+	    export PATH; \
+	    cd build && \
+	    CC=$(WhatGccIsCalled) $(SHELL) configure \
+	          --enable-shared=no --host=$(PLATFORM) --build=$(PLATFORM)
+	touch $@
+
+stamp.ffi.shared:
+	$(RM) -rf $(LIBFFI_DIR) build-shared
+	$(TAR) -zxf $(LIBFFI_TARBALL)
+	mv $(LIBFFI_DIR) build-shared
+#	chmod +x ln
+	(set -o igncr 2>/dev/null) && set -o igncr; export SHELLOPTS; \
+	    PATH=`pwd`:$$PATH; \
+	    export PATH; \
+	    cd build-shared && \
+	    CC=$(WhatGccIsCalled) $(SHELL) configure \
+	          --enable-shared=yes --disable-static --host=$(PLATFORM) --build=$(PLATFORM)
+	touch $@
+
+ffi.h: stamp.ffi.static
+	$(CP) build/include/ffi.h .
+
+libffi.a: stamp.ffi.static
+	$(MAKE) -C build MAKEFLAGS=
+	$(CP) build/.libs/libffi.a .
+	$(RANLIB) libffi.a
+
+libffi-3.dll: stamp.ffi.shared
+	$(MAKE) -C build-shared MAKEFLAGS=
+	$(CP) build-shared/.libs/libffi-3.dll .
+
+libffi.dll.a: libffi-3.dll
+	$(CP) build-shared/.libs/libffi.dll.a .
+
+clean distclean maintainer-clean ::
+	$(RM) -f stamp.ffi.static stamp.ffi.shared ffi.h
+	$(RM) -f libffi.a libffi-3.dll libffi.dll.a
+	$(RM) -rf build
+	$(RM) -rf build-shared
+
+#-----------------------------------------------------------------------------
+#
+# binary-dist
+
+include $(TOP)/mk/target.mk
+
+binary-dist:
+	$(INSTALL_DIR)                         $(BIN_DIST_DIR)/libffi
+	$(INSTALL_DATA)    Makefile            $(BIN_DIST_DIR)/libffi/
+ifneq "$(HaveLibFFI)" "YES"
+	$(INSTALL_DATA)    $(BINDIST_STAMPS)   $(BIN_DIST_DIR)/libffi/
+  ifneq "$(INSTALL_PROGS)" ""
+	$(INSTALL_DATA)    $(INSTALL_PROGS)    $(BIN_DIST_DIR)/libffi/
+  endif
+  ifneq "$(INSTALL_LIBS)" ""
+	$(INSTALL_DATA)    $(INSTALL_LIBS)     $(BIN_DIST_DIR)/libffi/
+  endif
+  ifneq "$(INSTALL_HEADERS)" ""
+	$(INSTALL_HEADER)  $(INSTALL_HEADERS)  $(BIN_DIST_DIR)/libffi/
+  endif
+endif
+
diff --git a/libffi/libffi-3.0.4.tar.gz b/libffi/libffi-3.0.4.tar.gz
new file mode 100644
index 0000000000..0b20310aae
--- /dev/null
+++ b/libffi/libffi-3.0.4.tar.gz