Add change flag in addition to timestamp in Windows manifest logic

Essentially the same idea as with using target_state::changed in case
the timestamps are equal (due to insufficient resolution).

3 files changed, 15 insertions, 12 deletions

diff --git a/build2/cc/link b/build2/cc/link
index cd83516..9e9e7cf 100644
--- a/build2/cc/link
+++ b/build2/cc/link
@@ -112,7 +112,7 @@ namespace build2
 
       // Windows-specific (windows-manifest.cxx).
       //
-      path
+      pair<path, bool>
       windows_manifest (const file&, bool rpath_assembly) const;
 
     private:
diff --git a/build2/cc/link.cxx b/build2/cc/link.cxx
index bd2face..6d0c605 100644
--- a/build2/cc/link.cxx
+++ b/build2/cc/link.cxx
@@ -997,10 +997,12 @@ namespace build2
         if (!for_install)
           rpath_timestamp = windows_rpath_timestamp (t, bs, act, lo);
 
-        path mf (
-          windows_manifest (
-            t,
-            rpath_timestamp != timestamp_nonexistent));
+        pair<path, bool> p (
+          windows_manifest (t,
+                            rpath_timestamp != timestamp_nonexistent));
+
+        path& mf (p.first);
+        bool mf_cf (p.second); // Changed flag (timestamp resolution).
 
         timestamp mf_mt (file_mtime (mf));
 
@@ -1012,7 +1014,7 @@ namespace build2
           //
           manifest = mf + ".o";
 
-          if (mf_mt > file_mtime (manifest))
+          if (mf_mt > file_mtime (manifest) || mf_cf)
           {
             path of (relative (manifest));
 
@@ -1087,7 +1089,7 @@ namespace build2
         {
           manifest = move (mf); // Save for link.exe's /MANIFESTINPUT.
 
-          if (mf_mt > mt)
+          if (mf_mt > mt || mf_cf)
             update = true; // Manifest changed, force update.
         }
       }
diff --git a/build2/cc/windows-manifest.cxx b/build2/cc/windows-manifest.cxx
index 3b9c649..3a62fcc 100644
--- a/build2/cc/windows-manifest.cxx
+++ b/build2/cc/windows-manifest.cxx
@@ -36,9 +36,10 @@ namespace build2
     }
 
     // Generate a Windows manifest and if necessary create/update the manifest
-    // file corresponding to the exe{} target. Return the manifest file path.
+    // file corresponding to the exe{} target. Return the manifest file path
+    // as well as whether it was changed.
     //
-    path link::
+    pair<path, bool> link::
     windows_manifest (const file& t, bool rpath_assembly) const
     {
       tracer trace (x, "link::windows_manifest");
@@ -108,11 +109,11 @@ namespace build2
           getline (ifs, s, '\0');
 
           if (s == m)
-            return mf;
+            return make_pair (move (mf), false);
         }
         catch (const io_error&)
         {
-          // Whatever the reason we failed for , let's rewrite the file.
+          // Whatever the reason we failed for, let's rewrite the file.
         }
       }
 
@@ -130,7 +131,7 @@ namespace build2
         fail << "unable to write to " << m << ": " << e;
       }
 
-      return mf;
+      return make_pair (move (mf), true);
     }
   }
 }