Add ability to disable automatic rpath, support for custom rpath-link

Specifically, the new config.bin.rpath.auto variable can be used to disable
automatic addition of prerequisite library rpaths, for example:

$ b config.bin.rpath.auto=false

Note that in this case rpath-link is still added where normally required
and for targets that support it (Linux and *BSD).

The new config.bin.rpath_link and config.bin.rpath_link.auto have the same
semantics as config.bin.rpath* but for rpath-link.

2 files changed, 81 insertions, 23 deletions

diff --git a/build2/bin/init.cxx b/build2/bin/init.cxx
index 52197d2..f334769 100644
--- a/build2/bin/init.cxx
+++ b/build2/bin/init.cxx
@@ -61,11 +61,25 @@ namespace build2
       vp.insert<string>    ("config.bin.target",   true);
       vp.insert<string>    ("config.bin.pattern",  true);
 
+      // Library types to build.
+      //
       vp.insert<string>    ("config.bin.lib",      true);
+
+      // Library types to use (in priority order).
+      //
       vp.insert<strings>   ("config.bin.exe.lib",  true);
       vp.insert<strings>   ("config.bin.liba.lib", true);
       vp.insert<strings>   ("config.bin.libs.lib", true);
-      vp.insert<dir_paths> ("config.bin.rpath",    true);
+
+      // The rpath[_link].auto flag controls automatic rpath behavior, for
+      // example, addition of rpaths for prerequisite libraries (see the cc
+      // module for an example). Default is true.
+      //
+      vp.insert<dir_paths> ("config.bin.rpath",      true);
+      vp.insert<bool>      ("config.bin.rpath.auto", true);
+
+      vp.insert<dir_paths> ("config.bin.rpath_link",      true);
+      vp.insert<bool>      ("config.bin.rpath_link.auto", true);
 
       vp.insert<string>    ("config.bin.prefix", true);
       vp.insert<string>    ("config.bin.suffix", true);
@@ -75,10 +89,16 @@ namespace build2
       vp.insert<string>    ("config.bin.exe.suffix", true);
 
       vp.insert<string>    ("bin.lib");
+
       vp.insert<strings>   ("bin.exe.lib");
       vp.insert<strings>   ("bin.liba.lib");
       vp.insert<strings>   ("bin.libs.lib");
+
       vp.insert<dir_paths> ("bin.rpath");
+      vp.insert<bool>      ("bin.rpath.auto");
+
+      vp.insert<dir_paths> ("bin.rpath_link");
+      vp.insert<bool>      ("bin.rpath_link.auto");
 
       // Link whole archive. Note: non-overridable with target visibility.
       //
@@ -183,14 +203,33 @@ namespace build2
           v = *required (rs, "config.bin.libs.lib", libs_lib).first;
       }
 
-      // config.bin.rpath
+      // config.bin.rpath[_link]
       //
-      // This one is optional and we merge it into bin.rpath, if any.
-      // See the cxx module for details on merging.
+      // These ones are optional and we merge them into bin.rpath[_link], if
+      // any.
       //
       rs.assign ("bin.rpath") += cast_null<dir_paths> (
         optional (rs, "config.bin.rpath"));
 
+      rs.assign ("bin.rpath_link") += cast_null<dir_paths> (
+        optional (rs, "config.bin.rpath_link"));
+
+      // config.bin.rpath[_link].auto
+      //
+      {
+        lookup l;
+
+        rs.assign ("bin.rpath.auto") =
+          (l = omitted (rs, "config.bin.rpath.auto").first)
+          ? cast<bool> (l)
+          : true;
+
+        rs.assign ("bin.rpath_link.auto") =
+          (l = omitted (rs, "config.bin.rpath_link.auto").first)
+          ? cast<bool> (l)
+          : true;
+      }
+
       // config.bin.{lib,exe}.{prefix,suffix}
       //
       // These ones are not used very often so we will omit them from the
diff --git a/build2/cc/link-rule.cxx b/build2/cc/link-rule.cxx
index cffd731..ebfe452 100644
--- a/build2/cc/link-rule.cxx
+++ b/build2/cc/link-rule.cxx
@@ -1457,20 +1457,20 @@ namespace build2
                      const scope& bs,
                      action a,
                      linfo li,
-                     bool for_install) const
+                     bool link) const
     {
-      // Use -rpath-link on targets that support it (Linux, *BSD). Note
+      // Use -rpath-link only on targets that support it (Linux, *BSD). Note
       // that we don't really need it for top-level libraries.
       //
-      if (for_install)
+      if (link)
       {
         if (tclass != "linux" && tclass != "bsd")
           return;
       }
 
-      auto imp = [for_install] (const file& l, bool la)
+      auto imp = [link] (const file& l, bool la)
       {
-        // If we are not installing, then we only need to rpath interface
+        // If we are not rpath-link'ing, then we only need to rpath interface
         // libraries (they will include rpath's for their implementations)
         // Otherwise, we have to do this recursively. In both cases we also
         // want to see through utility libraries.
@@ -1484,7 +1484,7 @@ namespace build2
         // except for some noise on the command line.
         //
         //
-        return (for_install ? !la : false) || l.is_a<libux> ();
+        return (link ? !la : false) || l.is_a<libux> ();
       };
 
       // Package the data to keep within the 2-pointer small std::function
@@ -1493,8 +1493,8 @@ namespace build2
       struct
       {
         strings& args;
-        bool for_install;
-      } d {args, for_install};
+        bool     link;
+      } d {args, link};
 
       auto lib = [&d, this] (const file* const* lc,
                              const string& f,
@@ -1547,7 +1547,7 @@ namespace build2
         // Ok, if we are here then it means we have a non-system, shared
         // library and its absolute path is in f.
         //
-        string o (d.for_install ? "-Wl,-rpath-link," : "-Wl,-rpath,");
+        string o (d.link ? "-Wl,-rpath-link," : "-Wl,-rpath,");
 
         size_t p (path::traits::rfind_separator (f));
         assert (p != string::npos);
@@ -1574,7 +1574,7 @@ namespace build2
             (la = (f = pt->is_a<libux> ())) ||
             (      f = pt->is_a<libs>  ()))
         {
-          if (!for_install && !la)
+          if (!link && !la)
           {
             // Top-level shared library dependency.
             //
@@ -1613,6 +1613,9 @@ namespace build2
       const file& t (xt.as<file> ());
       const path& tp (t.path ());
 
+      const scope& bs (t.base_scope ());
+      const scope& rs (*bs.root_scope ());
+
       match_data& md (t.data<match_data> ());
 
       // Unless the outer install rule signalled that this is update for
@@ -1623,9 +1626,6 @@ namespace build2
 
       bool for_install (*md.for_install);
 
-      const scope& bs (t.base_scope ());
-      const scope& rs (*bs.root_scope ());
-
       ltype lt (link_type (t));
       otype ot (lt.type);
       linfo li (link_info (bs, ot));
@@ -1682,7 +1682,7 @@ namespace build2
         // assembly itself is generated later, after updating the target. Omit
         // it if we are updating for install.
         //
-        if (!for_install)
+        if (!for_install && cast_true<bool> (t["bin.rpath.auto"]))
           rpath_timestamp = windows_rpath_timestamp (t, bs, a, li);
 
         auto p (windows_manifest (t, rpath_timestamp != timestamp_nonexistent));
@@ -1921,12 +1921,15 @@ namespace build2
         if (tclass == "windows")
         {
           // Limited emulation for Windows with no support for user-defined
-          // rpaths.
+          // rpath/rpath-link.
           //
-          auto l (t["bin.rpath"]);
+          lookup l;
 
-          if (l && !l->empty ())
+          if ((l = t["bin.rpath"]) && !l->empty ())
             fail << ctgt << " does not support rpath";
+
+          if ((l = t["bin.rpath_link"]) && !l->empty ())
+            fail << ctgt << " does not support rpath-link";
         }
         else
         {
@@ -1970,11 +1973,27 @@ namespace build2
           // rpath of the imported libraries (i.e., we assume they are also
           // installed). But we add -rpath-link for some platforms.
           //
-          rpath_libraries (sargs, t, bs, a, li, for_install);
+          if (cast_true<bool> (t[for_install
+                                 ? "bin.rpath_link.auto"
+                                 : "bin.rpath.auto"]))
+            rpath_libraries (sargs, t, bs, a, li, for_install /* link */);
 
-          if (auto l = t["bin.rpath"])
+          lookup l;
+
+          if ((l = t["bin.rpath"]) && !l->empty ())
             for (const dir_path& p: cast<dir_paths> (l))
               sargs.push_back ("-Wl,-rpath," + p.string ());
+
+          if ((l = t["bin.rpath_link"]) && !l->empty ())
+          {
+            // Only certain targets support -rpath-link (Linux, *BSD).
+            //
+            if (tclass != "linux" && tclass != "bsd")
+              fail << ctgt << " does not support rpath-link";
+
+            for (const dir_path& p: cast<dir_paths> (l))
+              sargs.push_back ("-Wl,-rpath-link," + p.string ());
+          }
         }
       }