Improve support for cross-compilation

Patchset from Stephen Blackheath <stephen.blackheath@ipwnstudios.com>

13 files changed, 224 insertions, 66 deletions

diff --git a/aclocal.m4 b/aclocal.m4
index 8318452913..14c9d4c4aa 100644
--- a/aclocal.m4
+++ b/aclocal.m4
@@ -526,7 +526,8 @@ AC_DEFUN([FP_EVAL_STDERR],
 # XXX
 #
 # $1 = the variable to set
-# $2 = the command to look for
+# $2 = the with option name
+# $3 = the command to look for
 #
 AC_DEFUN([FP_ARG_WITH_PATH_GNU_PROG],
 [
@@ -544,10 +545,14 @@ AC_ARG_WITH($2,
 [
     if test "$HostOS" != "mingw32"
     then
-        AC_PATH_PROG([$1], [$2])
+        if test "$target_alias" = "" ; then
+            AC_PATH_PROG([$1], [$3])
+        else
+            AC_PATH_PROG([$1], [$target_alias-$3])
+        fi
         if test -z "$$1"
         then
-            AC_MSG_ERROR([cannot find $2 in your PATH, no idea how to link])
+            AC_MSG_ERROR([cannot find $3 in your PATH, no idea how to link])
         fi
     fi
 ]
@@ -635,7 +640,7 @@ AC_CHECK_TYPE([$1], [], [], [$3])[]dnl
 m4_pushdef([fp_Cache], [AS_TR_SH([fp_cv_alignment_$1])])[]dnl
 AC_CACHE_CHECK([alignment of $1], [fp_Cache],
 [if test "$AS_TR_SH([ac_cv_type_$1])" = yes; then
-  FP_COMPUTE_INT([(long) (&((struct { char c; $1 ty; } *)0)->ty)],
+  FP_COMPUTE_INT([offsetof(struct { char c; $1 ty; },ty)],
                  [fp_Cache],
                  [AC_INCLUDES_DEFAULT([$3])],
                  [AC_MSG_ERROR([cannot compute alignment ($1)
@@ -1575,6 +1580,7 @@ AC_SUBST([ProjectPatchLevel])
 # timer_create() in certain versions of Linux (see bug #1933).
 #
 AC_DEFUN([FP_CHECK_TIMER_CREATE],
+if test "$cross_compiling" = "no" ; then
   [AC_CACHE_CHECK([for a working timer_create(CLOCK_REALTIME)], 
     [fptools_cv_timer_create_works],
     [AC_TRY_RUN([
@@ -1698,6 +1704,7 @@ case $fptools_cv_timer_create_works in
     yes) AC_DEFINE([USE_TIMER_CREATE], 1, 
                    [Define to 1 if we can use timer_create(CLOCK_PROCESS_CPUTIME_ID,...)]);;
 esac
+fi
 ])
 
 # FP_ICONV
@@ -1996,6 +2003,10 @@ AC_DEFUN([XCODE_VERSION],[
 # FIND_GCC()
 # --------------------------------
 # Finds where gcc is
+#
+# $1 = the variable to set
+# $2 = the with option name
+# $3 = the command to look for
 AC_DEFUN([FIND_GCC],[
     if test "$TargetOS_CPP" = "darwin" &&
        test "$XCodeVersion1" -eq 4 &&
@@ -2004,13 +2015,11 @@ AC_DEFUN([FIND_GCC],[
         # In Xcode 4.1, 'gcc-4.2' is the gcc legacy backend (rather
         # than the LLVM backend). We prefer the legacy gcc, but in
         # Xcode 4.2 'gcc-4.2' was removed.
-        FP_ARG_WITH_PATH_GNU_PROG([CC], [gcc-4.2])
+        FP_ARG_WITH_PATH_GNU_PROG([$1], [gcc-4.2], [gcc-4.2])
     else
-        FP_ARG_WITH_PATH_GNU_PROG([CC], [gcc])
+        FP_ARG_WITH_PATH_GNU_PROG([$1], [$2], [$3])
     fi
-    export CC
-    WhatGccIsCalled="$CC"
-    AC_SUBST(WhatGccIsCalled)
+    AC_SUBST($1)
 ])
 
 # LocalWords:  fi
diff --git a/compiler/ghc.mk b/compiler/ghc.mk
index 8790df361e..d5607ee60c 100644
--- a/compiler/ghc.mk
+++ b/compiler/ghc.mk
@@ -150,6 +150,10 @@ $(eval $(call clean-target,compiler,config_hs,compiler/main/Config.hs))
 
 PLATFORM_H = ghc_boot_platform.h
 
+ifeq "$(BuildingCrossCompiler)" "YES"
+compiler/stage1/$(PLATFORM_H) : compiler/stage2/$(PLATFORM_H)
+	cp $< $@
+else
 compiler/stage1/$(PLATFORM_H) : mk/config.mk mk/project.mk | $$(dir $$@)/.
 	$(call removeFiles,$@)
 	@echo "Creating $@..."
@@ -192,6 +196,7 @@ endif
 	@echo                                                    >> $@
 	@echo "#endif /* __PLATFORM_H__ */"                      >> $@
 	@echo "Done."
+endif
 
 # For stage2 and above, the BUILD platform is the HOST of stage1, and
 # the HOST platform is the TARGET of stage1.  The TARGET remains the same
diff --git a/configure.ac b/configure.ac
index bf7e84895a..84f0849689 100644
--- a/configure.ac
+++ b/configure.ac
@@ -333,19 +333,75 @@ then
 fi
 AC_SUBST([SplitObjsBroken])
 
+dnl ** Building a cross compiler?
+dnl --------------------------------------------------------------
+BuildingCrossCompiler=NO
+PortingCompiler=NO
+CrossCompiling=NO
+# If 'host' and 'target' differ, then this means we are building a cross-compiler.
+if test "$host" != "$target" ; then
+    BuildingCrossCompiler=YES
+    CrossCompiling=YES
+    cross_compiling=yes   # This tells configure that it can accept just 'target',
+                          # otherwise you get
+                          #   configure: error: cannot run C compiled programs.
+                          #   If you meant to cross compile, use `--host'.
+fi
+if test "$build" != "$host" ; then
+    CrossCompiling=YES
+    PortingCompiler=YES
+fi
+# Note: cross_compiling is set to 'yes' in both 'port' and 'toolchain' cases
+if ! test "$host" == "$target" -o "$host" == "$build" ; then
+   AC_MSG_ERROR([
+You've selected:
+
+  build:  $build   (the architecture we're building on)
+  host:   $host    (the architecture the compiler we're building will execute on)
+  target: $target  (the architecture the compiler we're building will produce code for)
+
+host must equal build or target. The two allowed cases are:
+
+  --host=<arch> --target=<arch>   to _port_ GHC to run on a foreign architecture
+                                  and produce code for that architecture
+  --target=<arch>                 to build a cross compiler _toolchain_ that runs
+                                  locally but produces code for a foreign
+                                  architecture
+])
+fi
+if [[ "$CrossCompiling" == "YES" ]] ; then
+  CrossCompilePrefix="${target}-"
+else
+  CrossCompilePrefix=""
+fi
+TargetPlatformFull="${target}"
+AC_SUBST(BuildingCrossCompiler)  # 'toolchain' case
+AC_SUBST(PortingCompiler)        # 'port' case
+AC_SUBST(CrossCompiling)         # BuildingCrossCompiler OR PortingCompiler
+AC_SUBST(CrossCompilePrefix)
+AC_SUBST(TargetPlatformFull)
+AC_ARG_WITH([alien],
+[AC_HELP_STRING([--with-alien=ARG],
+  [Supply script for running target binaries locally when cross-compiling])],
+  [AlienScript="$withval"],
+  [AlienScript=""])
+AC_SUBST(AlienScript)
+
 dnl ** Which gcc to use?
 dnl --------------------------------------------------------------
-FIND_GCC()
+FIND_GCC([WhatGccIsCalled], [gcc], [gcc])
+CC="$WhatGccIsCalled"
+export CC
 
 dnl ** Which ld to use?
 dnl --------------------------------------------------------------
-FP_ARG_WITH_PATH_GNU_PROG([LD], [ld])
+FP_ARG_WITH_PATH_GNU_PROG([LD], [ld], [ld])
 LdCmd="$LD"
 AC_SUBST([LdCmd])
 
 dnl ** Which nm to use?
 dnl --------------------------------------------------------------
-FP_ARG_WITH_PATH_GNU_PROG([NM], [nm])
+FP_ARG_WITH_PATH_GNU_PROG([NM], [nm], [nm])
 NmCmd="$NM"
 AC_SUBST([NmCmd])
 
@@ -642,17 +698,19 @@ dnl ** check for more functions
 dnl ** The following have been verified to be used in ghc/, but might be used somewhere else, too.
 AC_CHECK_FUNCS([getclock getrusage gettimeofday setitimer siginterrupt sysconf times ctime_r sched_setaffinity setlocale])
 
-AC_TRY_RUN([
-#include <sys/types.h>
-#include <sys/time.h>
-int main(void) {
-  struct itimerval tval;
-  tval.it_value.tv_sec = 1;
-  tval.it_value.tv_usec = 0;
-  tval.it_interval = tval.it_value;
-  return setitimer(ITIMER_VIRTUAL, &tval, (void*)0) != 0;
-}
-],[AC_DEFINE([HAVE_SETITIMER_VIRTUAL], [1], [Define to 1 if setitimer accepts ITIMER_VIRTUAL, 0 else.])])
+if test "$cross_compiling" = "no" ; then
+    AC_TRY_RUN([
+    #include <sys/types.h>
+    #include <sys/time.h>
+    int main(void) {
+      struct itimerval tval;
+      tval.it_value.tv_sec = 1;
+      tval.it_value.tv_usec = 0;
+      tval.it_interval = tval.it_value;
+      return setitimer(ITIMER_VIRTUAL, &tval, (void*)0) != 0;
+    }
+    ],[AC_DEFINE([HAVE_SETITIMER_VIRTUAL], [1], [Define to 1 if setitimer accepts ITIMER_VIRTUAL, 0 else.])])
+fi
 
 dnl ** On OS X 10.4 (at least), time.h doesn't declare ctime_r if
 dnl ** _POSIX_C_SOURCE is defined
@@ -852,8 +910,11 @@ echo ["\
 fi
 
 echo ["\
-   Using GCC             : $WhatGccIsCalled
-      which is version   : $GccVersion
+   Using GCC                 : $WhatGccIsCalled
+      which is version       : $GccVersion
+   Building a cross compiler : $BuildingCrossCompiler
+   Porting to foreign arch   : $PortingCompiler
+   Alien script              : $AlienScript
 
    ld       : $LdCmd
    Happy    : $HappyCmd ($HappyVersion)
diff --git a/ghc.mk b/ghc.mk
index 2ab85ec33a..fef5346838 100644
--- a/ghc.mk
+++ b/ghc.mk
@@ -380,7 +380,9 @@ endef
 define addPackage # args: $1 = package, $2 = condition
 ifneq "$(filter $1,$(PKGS_THAT_USE_TH)) $(GhcProfiled)" "$1 YES"
 ifeq "$(filter $1,$(PKGS_THAT_BUILD_WITH_STAGE2))" "$1"
+ifneq "$(BuildingCrossCompiler)" "YES"
 $(call addPackageGeneral,PACKAGES_STAGE2,$1,$2)
+endif
 else
 $(call addPackageGeneral,PACKAGES_STAGE1,$1,$2)
 endif
@@ -574,9 +576,15 @@ BUILD_DIRS += \
    $(GHC_GENPRIMOP_DIR)
 endif
 
+ifeq "$(BuildingCrossCompiler)-$(phase)" "YES-final"
+MAYBE_GHCI=
+else
+MAYBE_GHCI=driver/ghci
+endif
+
 BUILD_DIRS += \
    driver \
-   driver/ghci \
+   $(MAYBE_GHCI) \
    driver/ghc \
    driver/haddock \
    libffi \
@@ -600,24 +608,38 @@ else ifneq "$(findstring clean,$(MAKECMDGOALS))" ""
 BUILD_DIRS += libraries/integer-gmp/gmp
 endif
 
+ifeq "$(BuildingCrossCompiler)-$(phase)" "YES-final"
+MAYBE_COMPILER=
+MAYBE_GHCTAGS=
+MAYBE_HPC=
+MAYBE_RUNGHC=
+else
+MAYBE_COMPILER=compiler
+MAYBE_GHCTAGS=utils/ghctags
+MAYBE_HPC=utils/hpc
+MAYBE_RUNGHC=utils/runghc
+endif
+
 BUILD_DIRS += \
    utils/haddock \
    utils/haddock/doc \
-   compiler \
+   $(MAYBE_COMPILER) \
    $(GHC_HSC2HS_DIR) \
    $(GHC_PKG_DIR) \
    utils/testremove \
-   utils/ghctags \
+   $(MAYBE_GHCTAGS) \
    utils/ghc-pwd \
    $(GHC_CABAL_DIR) \
-   utils/hpc \
-   utils/runghc \
+   $(MAYBE_HPC) \
+   $(MAYBE_RUNGHC) \
    ghc
 
 ifneq "$(BINDIST)" "YES"
+ifneq "$(BuildingCrossCompiler)-$(phase)" "YES-final"
 BUILD_DIRS += \
    utils/mkUserGuidePart
 endif
+endif
 
 BUILD_DIRS += utils/count_lines
 BUILD_DIRS += utils/compare_sizes
@@ -810,7 +832,7 @@ else
 	done
 # We rename ghc-stage2, so that the right program name is used in error
 # messages etc.
-	"$(MV)" "$(DESTDIR)$(ghclibexecdir)/ghc-stage2" "$(DESTDIR)$(ghclibexecdir)/ghc"
+	"$(MV)" "$(DESTDIR)$(ghclibexecdir)/ghc-stage$(INSTALL_GHC_STAGE)" "$(DESTDIR)$(ghclibexecdir)/ghc"
 endif
 
 install_topdirs: $(INSTALL_TOPDIRS)
@@ -855,9 +877,11 @@ INSTALLED_GHC_REAL=$(DESTDIR)$(bindir)/ghc.exe
 INSTALLED_GHC_PKG_REAL=$(DESTDIR)$(bindir)/ghc-pkg.exe
 endif
 
-INSTALLED_PKG_DIRS := $(addprefix libraries/,$(PACKAGES_STAGE1)) \
-                      compiler \
-                      $(addprefix libraries/,$(PACKAGES_STAGE2))
+INSTALLED_PKG_DIRS := $(addprefix libraries/,$(PACKAGES_STAGE1))
+ifeq "$(BuildingCrossCompiler)" "NO"
+INSTALLED_PKG_DIRS := $(INSTALLED_PKG_DIRS) compiler
+endif
+INSTALLED_PKG_DIRS := $(INSTALLED_PKG_DIRS) $(addprefix libraries/,$(PACKAGES_STAGE2))
 ifeq "$(InstallExtraPackages)" "NO"
 INSTALLED_PKG_DIRS := $(filter-out $(addprefix libraries/,$(EXTRA_PACKAGES)),\
                                    $(INSTALLED_PKG_DIRS))
@@ -879,6 +903,7 @@ install_packages: rts/package.conf.install
 	"$(INSTALLED_GHC_PKG_REAL)" --force --global-conf "$(INSTALLED_PACKAGE_CONF)" update rts/package.conf.install
 	$(foreach p, $(INSTALLED_PKG_DIRS),                           \
 	    $(call make-command,                                      \
+                   CROSS_COMPILE="$(CrossCompilePrefix)"              \
 	           "$(GHC_CABAL_INPLACE)" install                     \
 	                                  "$(INSTALLED_GHC_REAL)"     \
 	                                  "$(INSTALLED_GHC_PKG_REAL)" \
diff --git a/ghc/ghc.mk b/ghc/ghc.mk
index 2af90bed28..022ee85a84 100644
--- a/ghc/ghc.mk
+++ b/ghc/ghc.mk
@@ -86,6 +86,10 @@ endif
 ifneq "$(filter-out 2,$(stage))" ""
 ghc_stage2_NOT_NEEDED = YES
 endif
+# When cross-compiling, the stage 1 compiler is our release compiler, so omit stage 2
+ifeq "$(BuildingCrossCompiler)" "YES"
+ghc_stage2_NOT_NEEDED = YES
+endif
 # stage 3 has to be requested explicitly with stage=3
 ifneq "$(stage)" "3"
 ghc_stage3_NOT_NEEDED = YES
@@ -147,7 +151,7 @@ install: install_ghc_link
 .PNONY: install_ghc_link
 install_ghc_link: 
 	$(call removeFiles,"$(DESTDIR)$(bindir)/ghc")
-	$(LN_S) ghc-$(ProjectVersion) "$(DESTDIR)$(bindir)/ghc"
+	$(LN_S) $(CrossCompilePrefix)ghc-$(ProjectVersion) "$(DESTDIR)$(bindir)/$(CrossCompilePrefix)ghc"
 else
 # On Windows we install the main binary as $(bindir)/ghc.exe
 # To get ghc-<version>.exe we have a little C program in driver/ghc
@@ -155,6 +159,6 @@ install: install_ghc_post
 .PHONY: install_ghc_post
 install_ghc_post: install_bins
 	$(call removeFiles,$(DESTDIR)$(bindir)/ghc.exe)
-	"$(MV)" -f $(DESTDIR)$(bindir)/ghc-stage$(INSTALL_GHC_STAGE).exe $(DESTDIR)$(bindir)/ghc.exe
+	"$(MV)" -f $(DESTDIR)$(bindir)/ghc-stage$(INSTALL_GHC_STAGE).exe $(DESTDIR)$(bindir)/$(CrossCompilePrefix)ghc.exe
 endif
 
diff --git a/includes/ghc.mk b/includes/ghc.mk
index ef994f2329..74edf55b1c 100644
--- a/includes/ghc.mk
+++ b/includes/ghc.mk
@@ -129,7 +129,7 @@ endif
 
 includes_DERIVEDCONSTANTS = includes/dist-derivedconstants/header/DerivedConstants.h
 
-ifeq "$(PORTING_HOST)" "YES"
+ifeq "$(PORTING_HOST)-$(AlienScript)" "YES-"
 
 DerivedConstants.h :
 	@echo "*** Cross-compiling: please copy DerivedConstants.h from the target system"
@@ -145,9 +145,18 @@ $(eval $(call build-prog,includes,dist-derivedconstants,0))
 $(includes_dist-derivedconstants_depfile_c_asm) : $(includes_H_CONFIG) $(includes_H_PLATFORM) $(includes_H_FILES) $$(rts_H_FILES)
 includes/dist-derivedconstants/build/mkDerivedConstants.o : $(includes_H_CONFIG) $(includes_H_PLATFORM)
 
+ifneq "$(AlienScript)" ""
+$(INPLACE_BIN)/mkDerivedConstants$(exeext): includes/$(includes_dist-derivedconstants_C_SRCS) | $$(dir $$@)/.
+	$(WhatGccIsCalled) -o $@ $< $(CFLAGS) $(includes_CC_OPTS)
+endif
+
 ifneq "$(BINDIST)" "YES"
 $(includes_DERIVEDCONSTANTS) : $(INPLACE_BIN)/mkDerivedConstants$(exeext) | $$(dir $$@)/.
+ifeq "$(AlienScript)" ""
 	./$< >$@
+else
+	$(AlienScript) run ./$< >$@
+endif
 endif
 
 endif
@@ -157,7 +166,7 @@ endif
 
 includes_GHCCONSTANTS = includes/dist-ghcconstants/header/GHCConstants.h
 
-ifeq "$(PORTING_HOST)" "YES"
+ifeq "$(PORTING_HOST)-$(AlienScript)" "YES-"
 
 $(includes_GHCCONSTANTS) :
 	@echo "*** Cross-compiling: please copy DerivedConstants.h from the target system"
@@ -176,8 +185,17 @@ $(includes_dist-ghcconstants_depfile_c_asm) : $(includes_H_CONFIG) $(includes_H_
 
 includes/dist-ghcconstants/build/mkDerivedConstants.o : $(includes_H_CONFIG) $(includes_H_PLATFORM)
 
+ifneq "$(AlienScript)" ""
+$(INPLACE_BIN)/mkGHCConstants$(exeext): includes/$(includes_dist-ghcconstants_C_SRCS) | $$(dir $$@)/.
+	$(WhatGccIsCalled) -o $@ $< $(CFLAGS) $(includes_CC_OPTS) $(includes_dist-ghcconstants_CC_OPTS)
+endif
+
 $(includes_GHCCONSTANTS) : $(INPLACE_BIN)/mkGHCConstants$(exeext) | $$(dir $$@)/.
+ifeq "$(AlienScript)" ""
 	./$< >$@
+else
+	$(AlienScript) run ./$< >$@
+endif
 endif
 
 endif
diff --git a/libffi/ghc.mk b/libffi/ghc.mk
index d9224108b4..879d482da8 100644
--- a/libffi/ghc.mk
+++ b/libffi/ghc.mk
@@ -82,7 +82,7 @@ $(libffi_STAMP_CONFIGURE): $(TOUCH_DEP)
 	          --prefix=$(TOP)/libffi/build/inst \
 	          --enable-static=yes \
 	          --enable-shared=$(libffi_EnableShared) \
-	          --host=$(HOSTPLATFORM) --build=$(BUILDPLATFORM)
+	          --host=$(TargetPlatformFull)
 
 	# wc on OS X has spaces in its output, which libffi's Makefile
 	# doesn't expect, so we tweak it to sed them out
diff --git a/mk/config.mk.in b/mk/config.mk.in
index 58e22cb664..2b5bd46aba 100644
--- a/mk/config.mk.in
+++ b/mk/config.mk.in
@@ -139,7 +139,7 @@ PlatformSupportsSharedLibs = $(if $(filter $(TARGETPLATFORM),\
 # the compiler you build with is generating registerised binaries), but
 # the stage2 compiler will be an unregisterised binary.
 #
-ifneq "$(findstring $(HostArch_CPP), i386 x86_64 powerpc arm)" ""
+ifneq "$(findstring $(TargetArch_CPP), i386 x86_64 powerpc arm)" ""
 GhcUnregisterised=NO
 else
 GhcUnregisterised=YES
@@ -151,8 +151,8 @@ endif
 # Target platforms supported:
 #   i386, powerpc
 #   AIX is not supported 
-ArchSupportsNCG=$(strip $(patsubst $(HostArch_CPP), YES, $(findstring $(HostArch_CPP), i386 x86_64 powerpc sparc)))
-OsSupportsNCG=$(strip $(patsubst $(HostOS_CPP), YES, $(patsubst aix,,$(HostOS_CPP))))
+ArchSupportsNCG=$(strip $(patsubst $(TargetArch_CPP), YES, $(findstring $(TargetArch_CPP), i386 x86_64 powerpc sparc)))
+OsSupportsNCG=$(strip $(patsubst $(TargetOS_CPP), YES, $(patsubst aix,,$(TargetOS_CPP))))
 
 # lazy test, because $(GhcUnregisterised) might be set in build.mk later.
 GhcWithNativeCodeGen=$(strip\
@@ -163,7 +163,7 @@ HaveLibDL = @HaveLibDL@
 
 # ArchSupportsSMP should be set iff there is support for that arch in
 # includes/stg/SMP.h
-ArchSupportsSMP=$(strip $(patsubst $(HostArch_CPP), YES, $(findstring $(HostArch_CPP), i386 x86_64 sparc powerpc arm)))
+ArchSupportsSMP=$(strip $(patsubst $(TargetArch_CPP), YES, $(findstring $(TargetArch_CPP), i386 x86_64 sparc powerpc arm)))
 
 # lazy test, because $(GhcUnregisterised) might be set in build.mk later.
 GhcWithSMP=$(strip $(if $(filter YESNO, $(ArchSupportsSMP)$(GhcUnregisterised)),YES,NO))
@@ -171,8 +171,8 @@ GhcWithSMP=$(strip $(if $(filter YESNO, $(ArchSupportsSMP)$(GhcUnregisterised)),
 # Whether to include GHCi in the compiler.  Depends on whether the RTS linker
 # has support for this OS/ARCH combination.
 
-OsSupportsGHCi=$(strip $(patsubst $(HostOS_CPP), YES, $(findstring $(HostOS_CPP), mingw32 cygwin32 linux solaris2 freebsd dragonfly netbsd openbsd darwin kfreebsdgnu)))
-ArchSupportsGHCi=$(strip $(patsubst $(HostArch_CPP), YES, $(findstring $(HostArch_CPP), i386 x86_64 powerpc sparc sparc64)))
+OsSupportsGHCi=$(strip $(patsubst $(TargetOS_CPP), YES, $(findstring $(TargetOS_CPP), mingw32 cygwin32 linux solaris2 freebsd dragonfly netbsd openbsd darwin kfreebsdgnu)))
+ArchSupportsGHCi=$(strip $(patsubst $(TargetArch_CPP), YES, $(findstring $(TargetArch_CPP), i386 x86_64 powerpc sparc sparc64)))
 
 ifeq "$(OsSupportsGHCi)$(ArchSupportsGHCi)" "YESYES"
 GhcWithInterpreter=YES
@@ -194,7 +194,7 @@ endif
 # Whether to use libffi for adjustors (foreign import "wrapper") or
 # not.  If we have built-in support (rts/Adjustor.c) then we use that,
 # otherwise we fall back on libffi, which is slightly slower.
-ArchHasAdjustorSupport = $(if $(findstring $(HostArch_CPP),i386 x86_64),YES,NO)
+ArchHasAdjustorSupport = $(if $(findstring $(TargetArch_CPP),i386 x86_64),YES,NO)
 ifeq "$(ArchHasAdjustorSupport)" "YES"
 UseLibFFIForAdjustors=NO
 else
@@ -515,9 +515,6 @@ GHC_STAGE1  = $(INPLACE_BIN)/ghc-stage1$(exeext)
 GHC_STAGE2  = $(INPLACE_BIN)/ghc-stage2$(exeext)
 GHC_STAGE3  = $(INPLACE_BIN)/ghc-stage3$(exeext)
 
-# Install stage 2 by default, can be changed to 3
-INSTALL_GHC_STAGE=2
-
 BOOTSTRAPPING_CONF = libraries/bootstrapping.conf
 
 INPLACE_PACKAGE_CONF = $(INPLACE_LIB)/package.conf.d
@@ -553,8 +550,17 @@ endif
 # the flag --with-gcc=<blah> instead.  The reason is that the configure script
 # needs to know which gcc you're using in order to perform its tests.
 
-WhatGccIsCalled = @WhatGccIsCalled@
-GccVersion      = @GccVersion@
+WhatGccIsCalled       = @WhatGccIsCalled@
+GccVersion            = @GccVersion@
+AlienScript           = @AlienScript@
+ifeq "$(phase)" "0"
+CrossCompilePrefix    =
+else
+CrossCompilePrefix    = @CrossCompilePrefix@
+endif
+# TargetPlatformFull retains the string passed to configure so we have it in
+# the necessary format to pass to libffi's configure.
+TargetPlatformFull    = @TargetPlatformFull@
 GccLT34         = @GccLT34@
 GccLT46         = @GccLT46@
 CC              = $(WhatGccIsCalled)
@@ -568,6 +574,22 @@ AS_STAGE1       = $(AS)
 AS_STAGE2       = $(AS)
 AS_STAGE3       = $(AS)
 
+# Cross-compiling options
+#
+# The 'toolchain' case: Cross-compiler to run locally:
+BuildingCrossCompiler = @BuildingCrossCompiler@
+# The 'port' case: Porting to a foreign architecture:
+PortingCompiler       = @PortingCompiler@
+# BuildingCrossCompiler OR PortingCompiler
+CrossCompiling        = @CrossCompiling@
+
+# Install stage 2 by default, or stage 1 in the cross compiler case. Can be changed to 3
+ifeq "$(BuildingCrossCompiler)" "YES"
+INSTALL_GHC_STAGE=1
+else
+INSTALL_GHC_STAGE=2
+endif
+
 # C compiler and linker flags from configure (e.g. -m<blah> to select
 # correct C compiler backend). The stage number is the stage of GHC
 # that is being used to compile with.
@@ -596,6 +618,9 @@ SRC_HSC2HS_OPTS += --cross-safe
 endif
 SRC_HSC2HS_OPTS += $(addprefix --cflag=,$(filter-out -O,$(SRC_CC_OPTS) $(CONF_CC_OPTS_STAGE0)))
 SRC_HSC2HS_OPTS += $(foreach d,$(GMP_INCLUDE_DIRS),-I$(d))
+ifeq "$(CrossCompiling)" "YES"
+SRC_HSC2HS_OPTS += --cross-compile
+endif
 
 #-----------------------------------------------------------------------------
 # Mingwex Library
diff --git a/rules/build-package-data.mk b/rules/build-package-data.mk
index fd267b0347..d535e34cbe 100644
--- a/rules/build-package-data.mk
+++ b/rules/build-package-data.mk
@@ -79,7 +79,7 @@ $1/$2/build/autogen/cabal_macros.h : $1/$2/package-data.mk
 # for our build system, and registers the package for use in-place in
 # the build tree.
 $1/$2/package-data.mk : $$(GHC_CABAL_INPLACE) $$($1_$2_GHC_PKG_DEP) $1/$$($1_PACKAGE).cabal $$(wildcard $1/configure) $$(LAX_DEPS_FOLLOW) $$($1_$2_HC_CONFIG_DEP)
-	"$$(GHC_CABAL_INPLACE)" configure --with-ghc="$$($1_$2_HC_CONFIG)" --with-ghc-pkg="$$($1_$2_GHC_PKG)" $$($1_CONFIGURE_OPTS) $$($1_$2_CONFIGURE_OPTS) -- $2 $1
+	CROSS_COMPILE="$(CrossCompilePrefix)" "$$(GHC_CABAL_INPLACE)" configure --with-ghc="$$($1_$2_HC_CONFIG)" --with-ghc-pkg="$$($1_$2_GHC_PKG)" $$($1_CONFIGURE_OPTS) $$($1_$2_CONFIGURE_OPTS) -- $2 $1
 ifeq "$$($1_$2_PROG)" ""
 ifneq "$$($1_$2_REGISTER_PACKAGE)" "NO"
 	"$$($1_$2_GHC_PKG)" update --force $$($1_$2_GHC_PKG_OPTS) $1/$2/inplace-pkg-config
diff --git a/rules/build-package.mk b/rules/build-package.mk
index d83a79d89d..ccd1659c30 100644
--- a/rules/build-package.mk
+++ b/rules/build-package.mk
@@ -133,7 +133,7 @@ CHECKED_$1 = YES
 check_packages: check_$1
 .PHONY: check_$1
 check_$1: $$(GHC_CABAL_INPLACE)
-	$$(GHC_CABAL_INPLACE) check $1
+	CROSS_COMPILE="$(CrossCompilePrefix)" $$(GHC_CABAL_INPLACE) check $1
 endif
 
 ifneq "$3" "0"
diff --git a/rules/haddock.mk b/rules/haddock.mk
index ff922ae978..0fc2043d67 100644
--- a/rules/haddock.mk
+++ b/rules/haddock.mk
@@ -42,7 +42,7 @@ endif
 ifneq "$$(BINDIST)" "YES"
 $$($$($1_PACKAGE)-$$($1_$2_VERSION)_HADDOCK_FILE) : $$(INPLACE_BIN)/haddock$$(exeext) $$(GHC_CABAL_INPLACE) $$($1_$2_HS_SRCS) $$($$($1_PACKAGE)-$$($1_$2_VERSION)_HADDOCK_DEPS) | $$$$(dir $$$$@)/.
 ifeq "$$(HSCOLOUR_SRCS)" "YES"
-	"$$(GHC_CABAL_INPLACE)" hscolour $2 $1
+	CROSS_COMPILE="$(CrossCompilePrefix)" "$$(GHC_CABAL_INPLACE)" hscolour $2 $1
 endif
 	"$$(TOP)/$$(INPLACE_BIN)/haddock" \
 	  --odir="$1/$2/doc/html/$$($1_PACKAGE)" \
diff --git a/rules/shell-wrapper.mk b/rules/shell-wrapper.mk
index 2376db137f..a291d852fe 100644
--- a/rules/shell-wrapper.mk
+++ b/rules/shell-wrapper.mk
@@ -62,7 +62,7 @@ BINDIST_WRAPPERS += $$($1_$2_SHELL_WRAPPER_NAME)
 install: install_$1_$2_wrapper
 
 .PHONY: install_$1_$2_wrapper
-install_$1_$2_wrapper: WRAPPER=$$(DESTDIR)$$(bindir)/$$($1_$2_INSTALL_SHELL_WRAPPER_NAME)
+install_$1_$2_wrapper: WRAPPER=$$(DESTDIR)$$(bindir)/$(CrossCompilePrefix)$$($1_$2_INSTALL_SHELL_WRAPPER_NAME)
 install_$1_$2_wrapper:
 	$$(call INSTALL_DIR,"$$(DESTDIR)$$(bindir)")
 	$$(call removeFiles,                                        "$$(WRAPPER)")
diff --git a/utils/ghc-pkg/ghc.mk b/utils/ghc-pkg/ghc.mk
index b6e762530a..b4302cc8e0 100644
--- a/utils/ghc-pkg/ghc.mk
+++ b/utils/ghc-pkg/ghc.mk
@@ -30,7 +30,7 @@ endif
 
 else
 
-$(GHC_PKG_INPLACE) : utils/ghc-pkg/dist/build/$(utils/ghc-pkg_dist_PROG)$(exeext) | $$(dir $$@)/. $(INPLACE_PACKAGE_CONF)/.
+$(GHC_PKG_INPLACE) : utils/ghc-pkg/dist/build/tmp/$(utils/ghc-pkg_dist_PROG)$(exeext) | $$(dir $$@)/. $(INPLACE_PACKAGE_CONF)/.
 	$(call removeFiles,$(wildcard $(INPLACE_PACKAGE_CONF)/*))
 ifeq "$(Windows)" "YES"
 	cp $< $@
@@ -51,7 +51,7 @@ endif
 #
 # ToDo: we might want to do this using ghc-cabal instead.
 #
-utils/ghc-pkg/dist/build/$(utils/ghc-pkg_dist_PROG)$(exeext): utils/ghc-pkg/Main.hs utils/ghc-pkg/Version.hs | bootstrapping/. $$(dir $$@)/. $(GHC_CABAL_INPLACE) 
+utils/ghc-pkg/dist/build/tmp/$(utils/ghc-pkg_dist_PROG)$(exeext): utils/ghc-pkg/Main.hs utils/ghc-pkg/Version.hs | bootstrapping/. $$(dir $$@)/. $(GHC_CABAL_INPLACE) 
 	"$(GHC)" $(SRC_HC_OPTS) --make utils/ghc-pkg/Main.hs -o $@ \
 	       -no-user-package-conf \
 	       -Wall -fno-warn-unused-imports -fno-warn-warnings-deprecations \
@@ -82,30 +82,41 @@ $(eval $(call clean-target,utils/ghc-pkg,dist,\
    utils/ghc-pkg/Version.hs))
 
 # -----------------------------------------------------------------------------
-# Building ghc-pkg with stage 1
+# Cross-compile case: Install our dist version
+# Normal case: Build ghc-pkg with stage 1
 
-utils/ghc-pkg_dist-install_USES_CABAL = YES
+ifeq "$(BuildingCrossCompiler)" "YES"
+GHC_PKG_DISTDIR=dist
+else
+GHC_PKG_DISTDIR=dist-install
+endif
+
+utils/ghc-pkg_$(GHC_PKG_DISTDIR)_USES_CABAL = YES
 utils/ghc-pkg_PACKAGE = ghc-pkg
 
-utils/ghc-pkg_dist-install_PROG = ghc-pkg
-utils/ghc-pkg_dist-install_SHELL_WRAPPER = YES
-utils/ghc-pkg_dist-install_INSTALL_SHELL_WRAPPER = YES
-utils/ghc-pkg_dist-install_INSTALL_SHELL_WRAPPER_NAME = ghc-pkg-$(ProjectVersion)
-utils/ghc-pkg_dist-install_INSTALL_INPLACE = NO
+utils/ghc-pkg_$(GHC_PKG_DISTDIR)_PROG = ghc-pkg
+utils/ghc-pkg_$(GHC_PKG_DISTDIR)_SHELL_WRAPPER = YES
+utils/ghc-pkg_$(GHC_PKG_DISTDIR)_INSTALL_SHELL_WRAPPER = YES
+utils/ghc-pkg_$(GHC_PKG_DISTDIR)_INSTALL_SHELL_WRAPPER_NAME = ghc-pkg-$(ProjectVersion)
+utils/ghc-pkg_$(GHC_PKG_DISTDIR)_INSTALL_INPLACE = NO
 
 ifeq "$(BootingFromHc)" "YES"
 utils/ghc-pkg_dist-install_OTHER_OBJS += $(ALL_STAGE1_LIBS) $(ALL_STAGE1_LIBS) $(ALL_STAGE1_LIBS) $(ALL_RTS_LIBS) $(libffi_STATIC_LIB)
 endif
 
+ifeq "$(BuildingCrossCompiler)" "YES"
+$(eval $(call shell-wrapper,utils/ghc-pkg,dist))
+else
 $(eval $(call build-prog,utils/ghc-pkg,dist-install,1))
+endif
 
 ifeq "$(Windows)" "NO"
 install: install_utils/ghc-pkg_link
 
-.PNONY: install_utils/ghc-pkg_link
+.PHONY: install_utils/ghc-pkg_link
 install_utils/ghc-pkg_link: 
 	$(call INSTALL_DIR,"$(DESTDIR)$(bindir)")
 	$(call removeFiles,"$(DESTDIR)$(bindir)/ghc-pkg")
-	$(LN_S) ghc-pkg-$(ProjectVersion) "$(DESTDIR)$(bindir)/ghc-pkg"
+	$(LN_S) $(CrossCompilePrefix)ghc-pkg-$(ProjectVersion) "$(DESTDIR)$(bindir)/$(CrossCompilePrefix)ghc-pkg"
 endif