[project @ 2005-01-14 08:01:26 by wolfgang]

Dynamic Linking, Part 2:

Hack the Makefiles to build dynamic libraries.
This allows you to actually use dynamic libraries to greatly reduce binary
sizes on Darwin/PowerPC and on powerpc64-linux (for now).

To use this, add the following to your build.mk

SplitObjs=NO
GhcBuildDylibs=YES
GhcStage2HcOpts=-dynamic
GhcLibHcOpts+=-fPIC -dynamic
GhcRtsHcOpts+=-fPIC -dynamic
GHC_CC_OPTS+=-fPIC

(You can leave out the last three lines on powerpc64-linux).

Then, to compile a program using dynamic libraries, pass the -dynamic option to GHC.
To make GHCi use the dynamic libraries instead of .o files, just delete the HS*.o files.

The dynamic library files are named libHSfoo_dyn.dylib or libHSfoo_dyn.so.

Note that the dynamic and static libraries are build from the same .o files,
but we really want to build the static libraries with SplitObjs and without
-fPIC -dynamic to achieve better code size and performance.

ghc/compiler/ghci/Linker.lhs:
    When looking for a library, look for HSfoo.o first (as before),
    then look for libHSfoo_dyn.[so/dylib] before looking for
    libHSfoo.[so/dylib].

ghc/compiler/main/DriverPipeline.hs:
    Main.dll_o and PrelMain.dll_o are dead, at least for now.

ghc/compiler/main/Packages.lhs:
    When -dynamic is specified, add "_dyn" to all libraries specified in
    hs-libraries (not to the extra-libs).

ghc/lib/compat/Makefile:
    Never build libghccompat as a dynamic lib.

mk/package.mk:
    if GhcBuildDylibs is set to YES, build dynamic libraries.

mk/target.mk:
    When installing .dylibs (Darwin only), update the install_name to point
    to the final location.
    (Somebody please read Apple's documentation on what install_names are,
    and then comment on whether this is a useful feature or whether it should
    be done the "normal" unix way).

6 files changed, 63 insertions, 8 deletions

diff --git a/ghc/compiler/ghci/Linker.lhs b/ghc/compiler/ghci/Linker.lhs
index 5b59b9d6fd..f897eecb15 100644
--- a/ghc/compiler/ghci/Linker.lhs
+++ b/ghc/compiler/ghci/Linker.lhs
@@ -822,9 +822,14 @@ locateOneObj dirs lib
   = do	{ mb_obj_path <- findFile mk_obj_path dirs 
 	; case mb_obj_path of
 	    Just obj_path -> return (Object obj_path)
-	    Nothing	  -> return (DLL lib) }		-- We assume
+	    Nothing	  -> 
+                do { mb_lib_path <- findFile mk_dyn_lib_path dirs
+                   ; case mb_lib_path of
+                       Just lib_path -> return (DLL (lib ++ "_dyn"))
+                       Nothing       -> return (DLL lib) }}		-- We assume
    where
      mk_obj_path dir = dir ++ '/':lib ++ ".o"
+     mk_dyn_lib_path dir = dir ++ '/':mkSOName (lib ++ "_dyn")
 
 
 -- ----------------------------------------------------------------------------
diff --git a/ghc/compiler/main/DriverPipeline.hs b/ghc/compiler/main/DriverPipeline.hs
index 9d8de34acb..d98dc20d7c 100644
--- a/ghc/compiler/main/DriverPipeline.hs
+++ b/ghc/compiler/main/DriverPipeline.hs
@@ -1080,8 +1080,7 @@ staticLink dflags o_files dep_packages = do
 
     let extra_os = if static || no_hs_main
                    then []
-                   else [ head (libraryDirs rts_pkg) ++ "/Main.dll_o",
-                          head (libraryDirs base_pkg) ++ "/PrelMain.dll_o" ]
+                   else []
 
     (md_c_flags, _) <- machdepCCOpts dflags
     SysTools.runLink dflags ( 
diff --git a/ghc/compiler/main/Packages.lhs b/ghc/compiler/main/Packages.lhs
index e90799e46a..081e801855 100644
--- a/ghc/compiler/main/Packages.lhs
+++ b/ghc/compiler/main/Packages.lhs
@@ -428,10 +428,9 @@ getPackageLinkOpts dflags pkgs = do
   rts_tag <- readIORef v_RTS_Build_tag
   static <- readIORef v_Static
   let 
-	imp        = if static then "" else "_imp"
-      	libs p     = map addSuffix (hACK (hsLibraries p)) ++ extraLibraries p
-	imp_libs p = map (++imp) (libs p)
-	all_opts p = map ("-l" ++) (imp_libs p) ++ extraLdOpts p
+	imp        = if static then "" else "_dyn"
+      	libs p     = map ((++imp) . addSuffix) (hACK (hsLibraries p)) ++ extraLibraries p
+	all_opts p = map ("-l" ++) (libs p) ++ extraLdOpts p
 
 	suffix     = if null tag then "" else  '_':tag
 	rts_suffix = if null rts_tag then "" else  '_':rts_tag
diff --git a/ghc/lib/compat/Makefile b/ghc/lib/compat/Makefile
index 2d5ef01789..39112beb06 100644
--- a/ghc/lib/compat/Makefile
+++ b/ghc/lib/compat/Makefile
@@ -63,4 +63,7 @@ boot :: depend
 	$(MAKE) all
 endif
 
+# We don't ever want to build libghccompat as a shared library.
+GhcBuildDylibs=NO
+
 include $(TOP)/mk/target.mk
diff --git a/mk/package.mk b/mk/package.mk
index bff2772058..93fed76075 100644
--- a/mk/package.mk
+++ b/mk/package.mk
@@ -1,5 +1,5 @@
 # -----------------------------------------------------------------------------
-# $Id: package.mk,v 1.42 2004/11/26 16:22:13 simonmar Exp $
+# $Id: package.mk,v 1.43 2005/01/14 08:01:27 wolfgang Exp $
 
 ifneq "$(PACKAGE)" ""
 
@@ -219,6 +219,52 @@ endif # DONT_WANT_STD_GHCI_LIB_RULE
 endif # GhcWithInterpreter
 endif # way
 
+ifeq "$(GhcBuildDylibs)" "YES"
+
+    # Build dynamic libraries.
+    # Currently, this is a hack. Anyone, PLEASE clean it up.
+
+    # For now, we pretend that there are two operating systems in the world;
+    # Darwin, and Everything Else. Furthermore, we pretend that Everything Else
+    # behaves like Linux.
+    
+ifeq "$(darwin_TARGET_OS)" "1"
+    # Darwin: Shared libraries end in .dylib
+DYLD_LIBRARY = $(patsubst %.a,%_dyn.dylib,$(LIBRARY))
+
+    # About the options used for Darwin:
+    # -dynamiclib
+    #   Apple's way of saying -shared
+    # -flat_namespace -undefined suppress:
+    #   Without these options, we'd have to specify the correct dependencies
+    #   for each of the dylibs. Twolevel namespaces are in general a good thing
+    #   (they make things more robust), so we should fix this sooner or later.
+    # -install_name
+    #   Causes the dynamic linker to ignore the DYLD_LIBRARY_PATH when loading
+    #   this lib and instead look for it at its absolute path.
+    #   When installing the .dylibs (see target.mk), we'll change that path to
+    #   point to the place they are installed.
+    #   Note: I'm not yet sure about this, but I think it will be convenient for
+    #         users not to have to set up DYLD_LIBRARY_PATH to point to the GHC
+    #         library dir. -- Wolfgang
+    
+$(DYLD_LIBRARY) : $(LIBOBJS) $(STUBOBJS)
+	$(CC) -dynamiclib -o $@ $(STUBOBJS) $(LIBOBJS) -flat_namespace -undefined suppress -install_name `pwd`/$@
+else
+DYLD_LIBRARY = $(patsubst %.a,%_dyn.so,$(LIBRARY))
+
+$(DYLD_LIBRARY) : $(LIBOBJS) $(STUBOBJS)
+	$(CC) -shared -o $@ $(STUBOBJS) $(LIBOBJS)
+endif
+
+INSTALL_LIBS += $(DYLD_LIBRARY)
+CLEAN_FILES += $(DYLD_LIBRARY)
+
+all :: $(DYLD_LIBRARY)
+
+
+endif
+
 # -----------------------------------------------------------------------------
 # Doc building with Haddock
 
diff --git a/mk/target.mk b/mk/target.mk
index 72420c9227..6749e29b25 100644
--- a/mk/target.mk
+++ b/mk/target.mk
@@ -770,6 +770,9 @@ install:: $(INSTALL_LIBS)
 		    $(INSTALL_DATA) -s $(INSTALL_OPTS) $$i $(libdir) ;; \
 		  *.so) \
 		    $(INSTALL_SHLIB) $(INSTALL_OPTS) $$i $(libdir) ;; \
+		  *.dylib) \
+		    $(INSTALL_SHLIB) $(INSTALL_OPTS) $$i $(libdir); \
+		    install_name_tool -id $(libdir)/`basename $$i` $(libdir)/`basename $$i` ;; \
 		  *) \
 		    $(INSTALL_DATA) $(INSTALL_OPTS) $$i $(libdir); \
 		esac; \