Add the -fno-shared-implib flag

Patch from
    Max Bolingbroke <batterseapower@hotmail.com>
Rerecorded to avoid conflicts.

4 files changed, 35 insertions, 1 deletions

diff --git a/compiler/main/DriverPipeline.hs b/compiler/main/DriverPipeline.hs
index 1849c6b91e..c4ac65f7b6 100644
--- a/compiler/main/DriverPipeline.hs
+++ b/compiler/main/DriverPipeline.hs
@@ -1590,7 +1590,9 @@ linkDynLib dflags o_files dep_packages = do
 	  , SysTools.Option "-o"
 	  , SysTools.FileOption "" output_fn
 	  , SysTools.Option "-shared"
-	  , SysTools.FileOption "-Wl,--out-implib=" (output_fn ++ ".a")
+	  ] ++
+	  [ SysTools.FileOption "-Wl,--out-implib=" (output_fn ++ ".a")
+	  | dopt Opt_SharedImplib dflags
 	  ]
 	 ++ map (SysTools.FileOption "") o_files
 	 ++ map SysTools.Option (
diff --git a/compiler/main/DynFlags.hs b/compiler/main/DynFlags.hs
index bebea761cd..37f1171eec 100644
--- a/compiler/main/DynFlags.hs
+++ b/compiler/main/DynFlags.hs
@@ -310,6 +310,7 @@ data DynFlag
    | Opt_GenManifest
    | Opt_EmbedManifest
    | Opt_EmitExternalCore
+   | Opt_SharedImplib
 
 	-- temporary flags
    | Opt_RunCPS
@@ -694,6 +695,8 @@ defaultDynFlags =
 
             Opt_DoAsmMangling,
 
+            Opt_SharedImplib,
+
             Opt_GenManifest,
             Opt_EmbedManifest,
             Opt_PrintBindContents
@@ -1742,6 +1745,7 @@ fFlags = [
   ( "gen-manifest",                     Opt_GenManifest, const Supported ),
   ( "embed-manifest",                   Opt_EmbedManifest, const Supported ),
   ( "ext-core",                         Opt_EmitExternalCore, const Supported ),
+  ( "shared-implib",                    Opt_SharedImplib, const Supported ),
   ( "implicit-import-qualified",        Opt_ImplicitImportQualified, const Supported )
   ]
 
diff --git a/docs/users_guide/flags.xml b/docs/users_guide/flags.xml
index bfffb096c4..0b22a396b7 100644
--- a/docs/users_guide/flags.xml
+++ b/docs/users_guide/flags.xml
@@ -1833,6 +1833,12 @@
 	      <entry>dynamic</entry>
 	      <entry>-</entry>
 	    </row>
+	    <row>
+	      <entry><option>-no-shared-implib</option></entry>
+	      <entry>Don't generate an import library for a DLL (Windows only)</entry>
+	      <entry>dynamic</entry>
+	      <entry>-</entry>
+	    </row>
 	  </tbody>
 	</tgroup>
       </informaltable>
diff --git a/docs/users_guide/phases.xml b/docs/users_guide/phases.xml
index 2026a34f59..ec1436434f 100644
--- a/docs/users_guide/phases.xml
+++ b/docs/users_guide/phases.xml
@@ -1052,6 +1052,28 @@ $ cat foo.hspp</screen>
               />).</para>
         </listitem>
       </varlistentry>
+          
+      <varlistentry>
+        <term>
+          <option>-fno-shared-implib</option>
+          <indexterm><primary><option>-fno-shared-implib</option></primary>
+          </indexterm>
+        </term>
+        <listitem>
+          <para>DLLs on Windows are typically linked to by linking to a corresponding
+            <literal>.lib</literal> or <literal>.dll.a</literal> - the so-called import library.
+            GHC will typically generate such a file for every DLL you create by compiling in
+            <literal>-shared</literal> mode. However, sometimes you don't want to pay the
+            disk-space cost of creating this import library, which can be substantial - it
+            might require as much space as the code itself, as Haskell DLLs tend to export
+            lots of symbols.</para>
+            
+          <para>As long as you are happy to only be able to link to the DLL using
+            <literal>GetProcAddress</literal> and friends, you can supply the
+            <option>-fno-shared-implib</option> flag to disable the creation of the import
+            library entirely.</para>
+        </listitem>
+      </varlistentry>
     </variablelist>
   </sect2>