Fix issues with interaction between binless logic and Windows DLLs

4 files changed, 46 insertions, 26 deletions

diff --git a/build2/cc/common.cxx b/build2/cc/common.cxx
index 6a1698e..ae125a5 100644
--- a/build2/cc/common.cxx
+++ b/build2/cc/common.cxx
@@ -614,9 +614,7 @@ namespace build2
       libs* s (nullptr);
 
       pair<path, path> pc; // pkg-config .pc file paths.
-
-      path f; // Reuse the buffer.
-      const dir_path* pd (nullptr);
+      path f;              // Reuse the buffer.
 
       auto search =[&a, &s, &pc,
                     &an, &ae,
@@ -670,7 +668,7 @@ namespace build2
                 // but valid timestamp (aka "trust me, it's there").
                 //
                 s->mtime (mt);
-                s->path (path ());
+                s->path (empty_path);
               }
             }
             else
@@ -787,6 +785,7 @@ namespace build2
       if (!usrd)
         usrd = extract_library_dirs (*p.scope);
 
+      const dir_path* pd (nullptr);
       for (const dir_path& d: *usrd)
       {
         if (search (d))
diff --git a/build2/cc/link-rule.cxx b/build2/cc/link-rule.cxx
index a2f2381..138ae9d 100644
--- a/build2/cc/link-rule.cxx
+++ b/build2/cc/link-rule.cxx
@@ -1238,6 +1238,12 @@ namespace build2
             // Linking a library to a shared library or executable.
             //
 
+            // Note: on Windows shared library could be the DLL with unknown
+            // location (empty path). See search_library() for details.
+            //
+            if (l->path ().empty () && l->member != nullptr) // Binless.
+              return;
+
             // On Windows a shared library is a DLL with the import library as
             // a first ad hoc group member. MinGW though can link directly to
             // DLLs (see search_library() for details).
@@ -1247,9 +1253,6 @@ namespace build2
                 tclass == "windows")
               l = &l->member->as<file> ();
 
-            if (l->path ().empty ()) // Binless.
-              return;
-
             string p (relative (l->path ()).string ());
 
             if (f & lflag_whole)
@@ -1349,6 +1352,16 @@ namespace build2
           if (d.li.type == otype::a && !lu)
             return;
 
+          // Note: on Windows shared library could be the DLL with unknown
+          // location (empty path). See search_library() for details.
+          //
+          if (l->path ().empty () && l->member != nullptr) // Binless.
+            return;
+
+          // Check if this library renders us out of date.
+          //
+          d.update = d.update || l->newer (d.mt);
+
           // On Windows a shared library is a DLL with the import library as a
           // first ad hoc group member. MinGW though can link directly to DLLs
           // (see search_library() for details).
@@ -1358,13 +1371,6 @@ namespace build2
               tclass == "windows")
             l = &l->member->as<file> ();
 
-          if (l->path ().empty ()) // Binless.
-            return;
-
-          // Check if this library renders us out of date.
-          //
-          d.update = d.update || l->newer (d.mt);
-
           d.cs.append (f);
           hash_path (d.cs, l->path (), d.out_root);
         }
diff --git a/build2/cc/pkgconfig.cxx b/build2/cc/pkgconfig.cxx
index b0634fb..cbc4c50 100644
--- a/build2/cc/pkgconfig.cxx
+++ b/build2/cc/pkgconfig.cxx
@@ -549,30 +549,38 @@ namespace build2
       //
       struct data
       {
-        pair<path, path> r;
+        path a;
+        path s;
         bool common;
-      } d {{}, common};
+      } d {path (), path (), common};
 
       auto check = [&d, &search_dir] (dir_path&& p) -> bool
       {
         // First look for static/shared-specific files.
         //
-        d.r.first  = search_dir (p, ".static");
-        d.r.second = search_dir (p, ".shared");
+        d.a = search_dir (p, ".static");
+        d.s = search_dir (p, ".shared");
 
-        if (!d.r.first.empty () || !d.r.second.empty ())
+        if (!d.a.empty () || !d.s.empty ())
           return false;
 
         // Then the common.
         //
         if (d.common)
-          d.r.first = d.r.second = search_dir (p, string ());
+          d.a = d.s = search_dir (p, "");
 
-        return d.r.first.empty ();
+        return d.a.empty ();
       };
 
-      pkgconfig_search (libd, check);
-      return d.r;
+      pair<path, path> r;
+
+      if (pkgconfig_search (libd, check))
+      {
+        r.first  = move (d.a);
+        r.second = move (d.s);
+      }
+
+      return r;
     };
 
     bool common::
@@ -1084,7 +1092,14 @@ namespace build2
       // the saving logic).
       //
       pkgconf& ipc (sp.empty () ? apc : spc); // Interface package info.
-      bool ibl ((sp.empty () ? at->path () : st->path ()).empty ()); // Binless.
+      bool ibl (sp.empty () // Binless.
+                ? at->path ().empty ()
+                //
+                // On Windows the shared library could be a DLL with an empty
+                // path (unknown location) and an ad hoc member that is the
+                // import library. See search_library() for details.
+                //
+                : st->path ().empty () && st->member != nullptr);
 
       bool pa (at != nullptr && !ap.empty ());
       if (pa || sp.empty ())
diff --git a/build2/cc/windows-rpath.cxx b/build2/cc/windows-rpath.cxx
index 507395c..e9fd680 100644
--- a/build2/cc/windows-rpath.cxx
+++ b/build2/cc/windows-rpath.cxx
@@ -77,7 +77,7 @@ namespace build2
         {
           // This can be an "undiscovered" DLL (see search_library()).
           //
-          if (!l->is_a<libs> () || l->path ().empty ()) // Covers binless.
+          if (!l->is_a<libs> () || l->path ().empty ()) // Also covers binless.
             return;
         }
         else
@@ -152,7 +152,7 @@ namespace build2
 
         if (l != nullptr)
         {
-          if (l->is_a<libs> () && !l->path ().empty ()) // Covers binless.
+          if (l->is_a<libs> () && !l->path ().empty ()) // Also covers binless.
           {
             // Get .pdb if there is one.
             //