Initial library support

11 files changed, 200 insertions, 76 deletions

diff --git a/build/b.cxx b/build/b.cxx
index e53844c..3fe9d20 100644
--- a/build/b.cxx
+++ b/build/b.cxx
@@ -139,8 +139,9 @@ main (int argc, char* argv[])
     target_types.insert (dir::static_type);
     target_types.insert (fsdir::static_type);
 
-    target_types.insert (exe::static_type);
     target_types.insert (obj::static_type);
+    target_types.insert (exe::static_type);
+    target_types.insert (lib::static_type);
 
     target_types.insert (cxx::h::static_type);
     target_types.insert (cxx::c::static_type);
@@ -157,6 +158,10 @@ main (int argc, char* argv[])
     rules[update_id][typeid (exe)].emplace ("cxx.gnu.link", cxx_link);
     rules[clean_id][typeid (exe)].emplace ("cxx.gnu.link", cxx_link);
 
+    rules[default_id][typeid (lib)].emplace ("cxx.gnu.link", cxx_link);
+    rules[update_id][typeid (lib)].emplace ("cxx.gnu.link", cxx_link);
+    rules[clean_id][typeid (lib)].emplace ("cxx.gnu.link", cxx_link);
+
     cxx::compile cxx_compile;
     rules[default_id][typeid (obj)].emplace ("cxx.gnu.compile", cxx_compile);
     rules[update_id][typeid (obj)].emplace ("cxx.gnu.compile", cxx_compile);
diff --git a/build/cxx/rule.cxx b/build/cxx/rule.cxx
index d8a7190..a7ec2a6 100644
--- a/build/cxx/rule.cxx
+++ b/build/cxx/rule.cxx
@@ -26,12 +26,15 @@ namespace build
 {
   namespace cxx
   {
+    // T is either target or scope.
+    //
+    template <typename T>
     static void
-    append_options (vector<const char*>& args, scope& s, const char* var)
+    append_options (vector<const char*>& args, T& s, const char* var)
     {
       if (auto val = s[var])
       {
-        for (const name& n: val.as<const list_value&> ())
+        for (const name& n: val.template as<const list_value&> ())
         {
           if (!n.type.empty () || !n.dir.empty ())
             fail << "expected option instead of " << n <<
@@ -43,9 +46,9 @@ namespace build
     }
 
     static void
-    append_std (vector<const char*>& args, scope& s, string& opt)
+    append_std (vector<const char*>& args, target& t, string& opt)
     {
-      if (auto val = s["cxx.std"])
+      if (auto val = t["cxx.std"])
       {
         const string& v (val.as<const string&> ());
 
@@ -95,7 +98,7 @@ namespace build
       obj& o (dynamic_cast<obj&> (t));
 
       if (o.path ().empty ())
-        o.path (o.dir / path (o.name + ".o"));
+        o.path (o.derived_path ("o"));
 
       // Search and match all the existing prerequisites. The injection
       // code (below) takes care of the ones it is adding.
@@ -182,14 +185,13 @@ namespace build
     {
       tracer trace ("cxx::compile::inject_prerequisites");
 
-      scope& ts (o.base_scope ());
-      scope& rs (*ts.root_scope ()); // Shouldn't have matched if nullptr.
+      scope& rs (*o.root_scope ()); // Shouldn't have matched if nullptr.
       const string& cxx (rs["config.cxx"].as<const string&> ());
 
       vector<const char*> args {cxx.c_str ()};
 
       append_options (args, rs, "config.cxx.poptions");
-      append_options (args, ts, "cxx.poptions");
+      append_options (args, o, "cxx.poptions");
 
       // @@ Some C++ options (e.g., -std, -m) affect the preprocessor.
       // Or maybe they are not C++ options? Common options?
@@ -197,9 +199,9 @@ namespace build
       append_options (args, rs, "config.cxx.coptions");
 
       string std; // Storage.
-      append_std (args, ts, std);
+      append_std (args, o, std);
 
-      append_options (args, ts, "cxx.coptions");
+      append_options (args, o, "cxx.coptions");
 
       args.push_back ("-MM"); // @@ Change to -M
       args.push_back ("-MG"); // Treat missing headers as generated.
@@ -268,7 +270,7 @@ namespace build
             //
             // Note that if the file has no extension, we record an empty
             // extension rather than NULL (which would signify that the
-            // extension needs to be added).
+            // default extension needs to be added).
             //
             dir_path d (f.directory ());
             string n (f.leaf ().base ().string ());
@@ -337,21 +339,20 @@ namespace build
       path relo (relative (o.path ()));
       path rels (relative (s->path ()));
 
-      scope& ts (o.base_scope ());
-      scope& rs (*ts.root_scope ()); // Shouldn't have matched if nullptr.
+      scope& rs (*o.root_scope ()); // Shouldn't have matched if nullptr.
       const string& cxx (rs["config.cxx"].as<const string&> ());
 
       vector<const char*> args {cxx.c_str ()};
 
       append_options (args, rs, "config.cxx.poptions");
-      append_options (args, ts, "cxx.poptions");
+      append_options (args, o, "cxx.poptions");
 
       append_options (args, rs, "config.cxx.coptions");
 
       string std; // Storage.
-      append_std (args, ts, std);
+      append_std (args, o, std);
 
-      append_options (args, ts, "cxx.coptions");
+      append_options (args, o, "cxx.coptions");
 
       args.push_back ("-o");
       args.push_back (relo.string ().c_str ());
@@ -461,12 +462,23 @@ namespace build
     {
       tracer trace ("cxx::link::apply");
 
-      // Derive executable file name from target name.
+      // Derive file name from target name.
       //
-      exe& e (dynamic_cast<exe&> (t));
+      bool so (false);
+      if (exe* e = dynamic_cast<exe*> (&t))
+      {
+        if (e->path ().empty ())
+          e->path (e->derived_path ());
+      }
+      else if (lib* l = dynamic_cast<lib*> (&t))
+      {
+        if (l->path ().empty ())
+          l->path (l->derived_path ("so", "lib"));
 
-      if (e.path ().empty ())
-        e.path (e.dir / path (e.name));
+        so = true;
+      }
+      else
+        assert (false);
 
       // We may need the project roots for rule chaining (see below).
       // We will resolve them lazily only if needed.
@@ -487,7 +499,7 @@ namespace build
           //
           target& pt (search (p));
 
-          if (a.operation () == clean_id && !pt.dir.sub (e.dir))
+          if (a.operation () == clean_id && !pt.dir.sub (t.dir))
             p.target = nullptr; // Ignore.
           else
             build::match (a, pt);
@@ -501,7 +513,7 @@ namespace build
           // but possible, the prerequisite is from a different project
           // altogether. So we are going to use the target's project.
           //
-          scope* rs (e.root_scope ());
+          scope* rs (t.root_scope ());
           assert (rs != nullptr); // Shouldn't have matched.
           out_root = &rs->path ();
           src_root = &rs->src_path ();
@@ -550,7 +562,7 @@ namespace build
         // update will come and finish the rewrite process (it will even
         // reuse op that we have created but then ignored). So all is good.
         //
-        if (a.operation () == clean_id && !ot.dir.sub (e.dir))
+        if (a.operation () == clean_id && !ot.dir.sub (t.dir))
         {
           // If we shouldn't clean obj{}, then it is fair to assume
           // we shouldn't clean cxx{} either (generated source will
@@ -561,6 +573,21 @@ namespace build
           continue;
         }
 
+        // Set the -fPIC option if we are building a shared object.
+        //
+        if (so)
+        {
+          auto var (ot.variables["cxx.coptions"]);
+
+          if (!var)
+          {
+            if (auto var1 = ot.base_scope ()["cxx.coptions"])
+              var = var1;
+          }
+
+          var += "-fPIC";
+        }
+
         // If this target already exists, then it needs to be "compatible"
         // with what we are doing here.
         //
@@ -633,42 +660,45 @@ namespace build
     }
 
     target_state link::
-    perform_update (action a, target& t)
+    perform_update (action a, target& xt)
     {
       // @@ Q:
       //
       // - what are we doing with libraries?
       //
+      path_target& t (static_cast<path_target&> (xt));
 
-      exe& e (dynamic_cast<exe&> (t));
+      //exe& e (dynamic_cast<exe&> (t));
 
-      if (!execute_prerequisites (a, e, e.mtime ()))
+      if (!execute_prerequisites (a, t, t.mtime ()))
         return target_state::unchanged;
 
       // Translate paths to relative (to working directory) ones. This
       // results in easier to read diagnostics.
       //
-      path rele (relative (e.path ()));
+      path relt (relative (t.path ()));
       vector<path> relo;
 
-      scope& ts (e.base_scope ());
-      scope& rs (*ts.root_scope ()); // Shouldn't have matched if nullptr.
+      scope& rs (*t.root_scope ()); // Shouldn't have matched if nullptr.
       const string& cxx (rs["config.cxx"].as<const string&> ());
 
       vector<const char*> args {cxx.c_str ()};
 
+      if (dynamic_cast<lib*> (&t) != nullptr)
+        args.push_back ("-shared");
+
       append_options (args, rs, "config.cxx.coptions");
 
       string std; // Storage.
-      append_std (args, ts, std);
+      append_std (args, t, std);
 
-      append_options (args, ts, "cxx.coptions");
+      append_options (args, t, "cxx.coptions");
 
       args.push_back ("-o");
-      args.push_back (rele.string ().c_str ());
+      args.push_back (relt.string ().c_str ());
 
       append_options (args, rs, "config.cxx.loptions");
-      append_options (args, ts, "cxx.loptions");
+      append_options (args, t, "cxx.loptions");
 
       for (const prerequisite& p: t.prerequisites)
       {
@@ -680,14 +710,14 @@ namespace build
       }
 
       append_options (args, rs, "config.cxx.libs");
-      append_options (args, ts, "cxx.libs");
+      append_options (args, t, "cxx.libs");
 
       args.push_back (nullptr);
 
       if (verb >= 1)
         print_process (args);
       else
-        text << "ld " << e;
+        text << "ld " << t;
 
       try
       {
@@ -701,7 +731,7 @@ namespace build
         // current clock time. It has the advantage of having the
         // subseconds precision.
         //
-        e.mtime (system_clock::now ());
+        t.mtime (system_clock::now ());
         return target_state::changed;
       }
       catch (const process_error& e)
diff --git a/build/native b/build/native
index 6107705..88f340d 100644
--- a/build/native
+++ b/build/native
@@ -9,6 +9,16 @@
 
 namespace build
 {
+  class obj: public file
+  {
+  public:
+    using file::file;
+
+  public:
+    virtual const target_type& type () const {return static_type;}
+    static const target_type static_type;
+  };
+
   class exe: public file
   {
   public:
@@ -19,7 +29,7 @@ namespace build
     static const target_type static_type;
   };
 
-  class obj: public file
+  class lib: public file
   {
   public:
     using file::file;
diff --git a/build/native.cxx b/build/native.cxx
index 8d58e66..d8b0149 100644
--- a/build/native.cxx
+++ b/build/native.cxx
@@ -8,6 +8,15 @@ using namespace std;
 
 namespace build
 {
+  const target_type obj::static_type
+  {
+    typeid (obj),
+    "obj",
+    &file::static_type,
+    &target_factory<obj>,
+    file::static_type.search
+  };
+
   const target_type exe::static_type
   {
     typeid (exe),
@@ -17,12 +26,12 @@ namespace build
     file::static_type.search
   };
 
-  const target_type obj::static_type
+  const target_type lib::static_type
   {
-    typeid (obj),
-    "obj",
+    typeid (lib),
+    "lib",
     &file::static_type,
-    &target_factory<obj>,
+    &target_factory<lib>,
     file::static_type.search
   };
 }
diff --git a/build/rule.cxx b/build/rule.cxx
index 413676b..884b28d 100644
--- a/build/rule.cxx
+++ b/build/rule.cxx
@@ -55,25 +55,14 @@ namespace build
         //
         path_target& pt (dynamic_cast<path_target&> (t));
 
+        // Assign the path. While nromally we shouldn't do this in match(),
+        // no other rule should ever be ambiguous with the fallback one.
+        //
         if (pt.path ().empty ())
         {
-          path p (t.dir / path (pt.name));
-
-          // @@ TMP: target name as an extension.
-          //
-          const string& e (pt.ext != nullptr ? *pt.ext : pt.type ().name);
-
-          if (!e.empty ())
-          {
-            p += '.';
-            p += e;
-          }
-
-          // While strictly speaking we shouldn't do this in match(),
-          // no other rule should ever be ambiguous with the fallback
-          // one.
+          // @@ TMP: using target name as the default extension.
           //
-          pt.path (move (p));
+          pt.path (pt.derived_path (pt.type ().name));
         }
 
         return pt.mtime () != timestamp_nonexistent ? &t : nullptr;
diff --git a/build/scope b/build/scope
index f9492e6..e4a8a7d 100644
--- a/build/scope
+++ b/build/scope
@@ -46,10 +46,13 @@ namespace build
     //
   public:
     value_proxy
-    operator[] (const std::string&);
+    operator[] (const variable&);
 
     value_proxy
-    operator[] (const variable&);
+    operator[] (const std::string& name)
+    {
+      return operator[] (variable_pool.find (name));
+    }
 
     const dir_path* src_path_ {nullptr}; // Cached src_{root,base} var value.
 
@@ -92,7 +95,7 @@ namespace build
 
     typedef dir_path_map<scope>::const_iterator iterator;
 
-    scope (): variables (*this) {}
+    scope (): variables (this) {}
 
     iterator i_;
     scope* parent_;
diff --git a/build/scope.cxx b/build/scope.cxx
index aced21b..6fb32b1 100644
--- a/build/scope.cxx
+++ b/build/scope.cxx
@@ -11,13 +11,6 @@ namespace build
   // scope
   //
   value_proxy scope::
-  operator[] (const string& name)
-  {
-    const variable& var (variable_pool.find (name));
-    return operator[] (var);
-  }
-
-  value_proxy scope::
   operator[] (const variable& var)
   {
     for (scope* s (this); s != nullptr; s = s->parent_scope ())
diff --git a/build/target b/build/target
index dd62ec8..5495061 100644
--- a/build/target
+++ b/build/target
@@ -20,6 +20,7 @@
 #include <build/map-key>       // map_iterator_adapter
 #include <build/timestamp>
 #include <build/name>
+#include <build/variable>
 #include <build/operation>
 #include <build/prerequisite>
 #include <build/utility>       // compare_*, extension_pool
@@ -93,12 +94,13 @@ namespace build
     ~target () = default;
 
     target (dir_path d, std::string n, const std::string* e)
-        : dir (std::move (d)), name (std::move (n)), ext (e) {}
+        : dir (std::move (d)), name (std::move (n)), ext (e),
+          variables (nullptr) {}
 
     const dir_path dir;     // Absolute and normalized.
     const std::string name;
-    const std::string* ext; // Extension, NULL means unspecified.
-
+    const std::string* ext; // Extension, NULL means unspecified,
+                            // empty means no extension.
   public:
     // Most qualified scope that contains this target.
     //
@@ -112,6 +114,8 @@ namespace build
     scope*
     root_scope () const;
 
+    // Prerequisites.
+    //
   public:
     typedef
     std::vector<std::reference_wrapper<prerequisite>>
@@ -119,6 +123,25 @@ namespace build
 
     prerequisites_type prerequisites;
 
+    // Target-specific variables.
+    //
+  public:
+    variable_map variables;
+
+    const variable_map&
+    ro_variables () const {return variables;}
+
+    // Variable lookup in this target and all its outer scopes.
+    //
+    value_proxy
+    operator[] (const variable&);
+
+    value_proxy
+    operator[] (const std::string& name)
+    {
+      return operator[] (variable_pool.find (name));
+    }
+
   public:
     target_state state;
 
@@ -328,6 +351,14 @@ namespace build
     void
     path (path_type p) {assert (path_.empty ()); path_ = std::move (p);}
 
+    // Return a path derived from target's dir, name, and, if specified,
+    // ext. If ext is not specified, then use default_ext. If name_prefix
+    // if not NULL, add it before the name part.
+    //
+    path_type
+    derived_path (const char* default_ext = nullptr,
+                  const char* name_prefix = nullptr);
+
   protected:
     virtual timestamp
     load_mtime () const;
diff --git a/build/target.cxx b/build/target.cxx
index db02979..fbba1ed 100644
--- a/build/target.cxx
+++ b/build/target.cxx
@@ -51,6 +51,16 @@ namespace build
     return scopes.find (dir).root_scope ();
   }
 
+  value_proxy target::
+  operator[] (const variable& var)
+  {
+    auto i (variables.find (var));
+
+    return i != variables.end ()
+      ? value_proxy (&i->second, nullptr)
+      : base_scope ()[var];
+  }
+
   ostream&
   operator<< (ostream& os, const target& t)
   {
@@ -232,6 +242,33 @@ namespace build
 
   // path_target
   //
+  path path_target::
+  derived_path (const char* de, const char* np)
+  {
+    string n;
+
+    if (np != nullptr)
+      n += np;
+
+    n += name;
+
+    if (ext != nullptr)
+    {
+      if (!ext->empty ())
+      {
+        n += '.';
+        n += *ext;
+      }
+    }
+    else if (de != nullptr)
+    {
+      n += '.';
+      n += de;
+    }
+
+    return dir / path_type (move (n));
+  }
+
   timestamp path_target::
   load_mtime () const
   {
diff --git a/build/variable b/build/variable
index f994b58..6c14477 100644
--- a/build/variable
+++ b/build/variable
@@ -100,7 +100,7 @@ namespace build
     explicit operator bool () const {return defined () && !null ();}
     explicit operator value_ptr& () const {return *p;}
 
-    scope_type* scope;
+    scope_type* scope; // If NULL, then this is a target variable.
 
     // Get interface. See available specializations below.
     //
@@ -119,6 +119,11 @@ namespace build
     const value_proxy&
     operator= (std::string) const;
 
+    // Append enother simple name to list_value.
+    //
+    const value_proxy&
+    operator+= (std::string) const;
+
     const value_proxy&
     operator= (dir_path) const;
 
@@ -218,7 +223,7 @@ namespace build
     value_proxy
     operator[] (const variable& v)
     {
-      return value_proxy (&base::operator[] (v), &scope_);
+      return value_proxy (&base::operator[] (v), scope_);
     }
 
     value_proxy
@@ -234,7 +239,7 @@ namespace build
       return i != end ()
         // @@ To do this properly we seem to need ro_value_proxy.
         //
-        ? value_proxy (&const_cast<value_ptr&> (i->second), &scope_)
+        ? value_proxy (&const_cast<value_ptr&> (i->second), scope_)
         : value_proxy (nullptr, nullptr);
     }
 
@@ -251,10 +256,11 @@ namespace build
     }
 
     explicit
-    variable_map (scope& s): scope_ (s) {}
+    variable_map (scope* s): scope_ (s) {}
 
   private:
-    scope& scope_; // Scope to which this map belongs (and all its value).
+    scope* scope_; // Scope to which this map belongs or NULL if this
+                   // is a target variable map.
   };
 }
 
diff --git a/build/variable.ixx b/build/variable.ixx
index 2d52d9f..c0059c5 100644
--- a/build/variable.ixx
+++ b/build/variable.ixx
@@ -37,6 +37,17 @@ namespace build
   }
 
   inline const value_proxy& value_proxy::
+  operator+= (std::string v) const
+  {
+    if (*p == nullptr)
+      *this = v;
+    else
+      as<list_value&> ().emplace_back (std::move (v));
+
+    return *this;
+  }
+
+  inline const value_proxy& value_proxy::
   operator= (dir_path v) const
   {
     p->reset (new list_value (std::move (v)));