Initial take on DLL support for MinGW toolchain

6 files changed, 157 insertions, 65 deletions

diff --git a/build2/algorithm b/build2/algorithm
index 19b3971..d7dddba 100644
--- a/build2/algorithm
+++ b/build2/algorithm
@@ -220,6 +220,18 @@ namespace build2
   //
   target_state
   perform_clean_depdb (action, target&);
+
+  // Helper for custom perform(clean) implementations that cleans extra files
+  // specified as a list of extensions. The extension string can be NULL, in
+  // which case it is ignored. Otherwise, the first character can be '+', in
+  // which case the extension is added (without the plus) to the existing
+  // extension (if any). In all other cases, the old extension is replaced
+  // with the new one. For example:
+  //
+  // clean_extra (a, t, {"+.d", ".lib"});
+  //
+  target_state
+  clean_extra (action, file&, initializer_list<const char*> extra_ext);
 }
 
 #include <build2/algorithm.ixx>
diff --git a/build2/algorithm.cxx b/build2/algorithm.cxx
index a22837f..17768e3 100644
--- a/build2/algorithm.cxx
+++ b/build2/algorithm.cxx
@@ -478,60 +478,81 @@ namespace build2
   }
 
   target_state
-  perform_clean (action a, target& t)
+  clean_extra (action a, file& ft, initializer_list<const char*> es)
   {
-    // The reverse order of update: first remove the file, then clean
-    // prerequisites.
+    // Clean the extras first and don't print the commands at verbosity level
+    // below 3.
     //
-    file& ft (dynamic_cast<file&> (t));
+    target_state er (target_state::unchanged);
+    path ef; // First extra file that actually got removed (see below).
 
-    target_state r (rmfile (ft.path (), ft)
-                    ? target_state::changed
-                    : target_state::unchanged);
+    for (const char* e: es)
+    {
+      if (e == nullptr)
+        continue;
 
-    // Update timestamp in case there are operations after us that
-    // could use the information.
-    //
-    ft.mtime (timestamp_nonexistent);
+      path f;
+      if (*e == '+')
+        f = ft.path () + ++e;
+      else
+        f = ft.path ().base () + e;
 
-    // Clean prerequisites.
-    //
-    r |= reverse_execute_prerequisites (a, t);
+      target_state r (rmfile (f, false)
+                      ? target_state::changed
+                      : target_state::unchanged);
 
-    return r;
-  }
+      if (r == target_state::changed && ef.empty ())
+      {
+        ef = move (f);
+      }
 
-  target_state
-  perform_clean_depdb (action a, target& t)
-  {
-    // Normally the .d file is created/updated before the target so remove it
-    // first. Also, don't print the command at verbosity level below 3.
-    //
-    file& ft (dynamic_cast<file&> (t));
+      er |= r;
+    }
 
-    path df (ft.path () + ".d");
-    target_state dr (rmfile (df, false)
+    // Now clean the primary target and its prerequisited in the reverse order
+    // of update: first remove the file, then clean the prerequisites.
+    //
+    target_state tr (rmfile (ft.path (), ft)
                      ? target_state::changed
                      : target_state::unchanged);
 
-    // Factor the result of removing the .d file into the target state. While
-    // strictly speaking removing it doesn't change the target state, if we
-    // don't do this, then we may end up removing the file but still saying
-    // that everything is clean (e.g., if someone removes the target file but
-    // leaves .d laying around). That would be confusing.
+    // Update timestamp in case there are operations after us that could use
+    // the information.
+    //
+    ft.mtime (timestamp_nonexistent);
+
+    // Clean prerequisites.
     //
-    target_state tr (perform_clean (a, t));
+    tr |= reverse_execute_prerequisites (a, ft);
 
+    // Factor the result of removing the extra files into the target state.
+    // While strictly speaking removing them doesn't change the target state,
+    // if we don't do this, then we may end up removing the file but still
+    // saying that everything is clean (e.g., if someone removes the target
+    // file but leaves the extra laying around). That would be confusing.
+    //
     // What would also be confusing is if we didn't print any commands in
     // this case.
     //
-    if (tr == target_state::unchanged && dr == target_state::changed)
+    if (tr != target_state::changed && er == target_state::changed)
     {
       if (verb > 0 && verb < 3)
-        text << "rm " << df;
+        text << "rm " << ef;
     }
 
-    tr |= dr;
+    tr |= er;
     return tr;
   }
+
+  target_state
+  perform_clean (action a, target& t)
+  {
+    return clean_extra (a, dynamic_cast<file&> (t), {});
+  }
+
+  target_state
+  perform_clean_depdb (action a, target& t)
+  {
+    return clean_extra (a, dynamic_cast<file&> (t), {"+.d"});
+  }
 }
diff --git a/build2/cxx/compile.cxx b/build2/cxx/compile.cxx
index bfeaeb9..b11a919 100644
--- a/build2/cxx/compile.cxx
+++ b/build2/cxx/compile.cxx
@@ -194,7 +194,7 @@ namespace build2
 
         if (t.is_a<objso> ())
         {
-          // On Darwin -fPIC is the default.
+          // On Darwin, Win32 -fPIC is the default.
           //
           if (tclass == "linux" || tclass == "freebsd")
             cs.append ("-fPIC");
@@ -610,7 +610,7 @@ namespace build2
 
         if (t.is_a<objso> ())
         {
-          // On Darwin -fPIC is the default.
+          // On Darwin, Win32 -fPIC is the default.
           //
           if (tclass == "linux" || tclass == "freebsd")
             args.push_back ("-fPIC");
@@ -1217,7 +1217,7 @@ namespace build2
       {
         if (t.is_a<objso> ())
         {
-          // On Darwin -fPIC is the default.
+          // On Darwin, Win32 -fPIC is the default.
           //
           if (tclass == "linux" || tclass == "freebsd")
             args.push_back ("-fPIC");
diff --git a/build2/cxx/link b/build2/cxx/link
index d0584de..ca45e17 100644
--- a/build2/cxx/link
+++ b/build2/cxx/link
@@ -28,6 +28,9 @@ namespace build2
       static target_state
       perform_update (action, target&);
 
+      static target_state
+      perform_clean (action, target&);
+
       static link instance;
 
     public:
diff --git a/build2/cxx/link.cxx b/build2/cxx/link.cxx
index 3d0255e..5792615 100644
--- a/build2/cxx/link.cxx
+++ b/build2/cxx/link.cxx
@@ -255,7 +255,7 @@ namespace build2
 
       scope& rs (*p.scope.root_scope ());
       const string& cid (cast<string> (rs["cxx.id"]));
-      const string& sys (cast<string> (rs["cxx.target.system"]));
+      const string& tsys (cast<string> (rs["cxx.target.system"]));
 
       bool l (p.is_a<lib> ());
       const string* ext (l ? nullptr : p.ext); // Only for liba/libso.
@@ -306,23 +306,31 @@ namespace build2
 
       if (l || p.is_a<libso> ())
       {
-        // @@ VC TODO
-        //
-
-        sn = path ("lib" + p.name);
+        const char* e ("");
 
-        if (ext == nullptr)
+        if (cid == "msvc")
         {
-          const char* e;
-          if (sys == "darwin")
-            e = "dylib";
-          else
-            e = "so";
+          // @@ VC TODO: still .lib, right?
+          //
+        }
+        else
+        {
+          sn = path ("lib" + p.name);
 
-          ext = &extension_pool.find (e);
+          if      (tsys == "darwin")  e = "dylib";
+          //
+          // @@ Here we are searching for the import library but if it's not
+          // found, then we could also search for the DLL since we can link
+          // directly to it. Of course, we would also need some way to mark
+          // this libso{} as "import-less".
+          //
+          else if (tsys == "mingw32") e = "dll.a";
+          else                        e = "so";
         }
 
-        se = ext;
+        se = ext == nullptr
+          ? &extension_pool.find (e)
+          : ext;
 
         if (!se->empty ())
         {
@@ -594,9 +602,11 @@ namespace build2
             {
               //@@ VC: DLL name.
 
-              if (tclass == "macosx") e = "dylib";
-              else                    e = "so";
-              if (p == nullptr)       p = "lib";
+              if (tclass == "macosx")  e = "dylib";
+              if (tclass == "windows") e = "dll";
+              else                     e = "so";
+
+              if (p == nullptr)        p = "lib";
             }
 
             t.derive_path (e, p);
@@ -817,7 +827,7 @@ namespace build2
       switch (a)
       {
       case perform_update_id: return &perform_update;
-      case perform_clean_id: return &perform_clean_depdb;
+      case perform_clean_id: return &perform_clean;
       default: return noop_recipe; // Configure update.
       }
     }
@@ -885,6 +895,7 @@ namespace build2
       scope& rs (t.root_scope ());
 
       const string& cid (cast<string> (rs["cxx.id"]));
+      const string& tsys (cast<string> (rs["cxx.target.system"]));
       const string& tclass (cast<string> (rs["cxx.target.class"]));
 
       const string& aid (lt == type::a
@@ -979,7 +990,7 @@ namespace build2
 
         // Set soname.
         //
-        if (so && cid != "msvc")
+        if (so && tclass != "windows")
         {
           const string& leaf (t.path ().leaf ().string ());
 
@@ -1016,9 +1027,11 @@ namespace build2
         // rpath of the imported libraries (i.e., we assume the are also
         // installed).
         //
-        // @@ VC TODO: emulate own rpath somehow and complain on user's.
-        //
-        if (cid != "msvc")
+        if (tclass == "windows")
+        {
+          // @@ VC TODO: emulate own rpath somehow and complain on user's.
+        }
+        else
         {
           for (target* pt: t.prerequisite_targets)
           {
@@ -1185,6 +1198,17 @@ namespace build2
 
           args.push_back ("-o");
           args.push_back (relt.string ().c_str ());
+
+          // Add any additional options (import library name, etc).
+          //
+          if (so)
+          {
+            if (tsys == "mingw32")
+            {
+              out = "-Wl,--out-implib=" + relt.string () + ".a";
+              args.push_back (out.c_str ());
+            }
+          }
         }
       }
 
@@ -1194,14 +1218,23 @@ namespace build2
       {
         path_target* ppt;
         liba* a (nullptr);
+        libso* so (nullptr);
 
         if ((ppt = pt->is_a<obja> ())  ||
             (ppt = pt->is_a<objso> ()) ||
             (lt != type::a &&
              ((ppt = a = pt->is_a<liba> ()) ||
-              (ppt = pt->is_a<libso> ()))))
+              (ppt = so = pt->is_a<libso> ()))))
         {
-          sargs.push_back (relative (ppt->path ()).string ()); // string()&&
+          string p (relative (ppt->path ()).string ()); // string()&&
+
+          if (so != nullptr)
+          {
+            if (tsys == "mingw32")
+              p += ".a"; // Link to the import library (*.dll -> *.dll.a).
+          }
+
+          sargs.push_back (move (p));
 
           // If this is a static library, link all the libraries it depends
           // on, recursively.
@@ -1305,6 +1338,25 @@ namespace build2
       return target_state::changed;
     }
 
+    target_state link::
+    perform_clean (action a, target& xt)
+    {
+      file& t (static_cast<file&> (xt));
+
+      scope& rs (t.root_scope ());
+      const string& tsys (cast<string> (rs["cxx.target.system"]));
+
+      const char* e (nullptr);
+
+      if (link_type (t) == type::so)
+      {
+        if (tsys == "mingw32")
+          e = "+.a"; // Import library (*.dll.a).
+      }
+
+      return clean_extra (a, t, {"+.d", e});
+    }
+
     link link::instance;
   }
 }
diff --git a/build2/types b/build2/types
index d3930ba..943c9e1 100644
--- a/build2/types
+++ b/build2/types
@@ -7,13 +7,15 @@
 
 #include <vector>
 #include <string>
-#include <memory>        // unique_ptr, shared_ptr
-#include <utility>       // pair, move()
-#include <cstddef>       // size_t, nullptr_t
-#include <cstdint>       // uint{8,16,32,64}_t
+#include <memory>           // unique_ptr, shared_ptr
+#include <utility>          // pair, move()
+#include <cstddef>          // size_t, nullptr_t
+#include <cstdint>          // uint{8,16,32,64}_t
 #include <istream>
 #include <ostream>
-#include <functional>    // function, reference_wrapper
+#include <functional>       // function, reference_wrapper
+#include <initializer_list>
+
 
 #include <exception>     // exception
 #include <stdexcept>     // logic_error, invalid_argument, runtime_error
@@ -44,6 +46,8 @@ namespace build2
   using std::function;
   using std::reference_wrapper;
 
+  using std::initializer_list;
+
   using std::unique_ptr;
   using std::shared_ptr;
   using std::weak_ptr;