From f19959de304afaff2b3d539c9bef1f493ede5fbd Mon Sep 17 00:00:00 2001
From: Boris Kolpackov <boris@codesynthesis.com>
Date: Tue, 22 Nov 2022 06:27:33 +0200
Subject: Add support for Objective-C/C++ compilation in cc module

---
 libbuild2/cxx/init.cxx   | 47 +++++++++++++++++++++++++++++++++++++++++++++++
 libbuild2/cxx/init.hxx   |  2 ++
 libbuild2/cxx/target.cxx | 18 ++++++++++++++----
 libbuild2/cxx/target.hxx | 16 ++++++++++++++++
 4 files changed, 79 insertions(+), 4 deletions(-)

(limited to 'libbuild2/cxx')

diff --git a/libbuild2/cxx/init.cxx b/libbuild2/cxx/init.cxx
index 5396056..fd6d04c 100644
--- a/libbuild2/cxx/init.cxx
+++ b/libbuild2/cxx/init.cxx
@@ -479,8 +479,10 @@ namespace build2
 
         "cxx",
         "c++",
+        "obj-c++",
         BUILD2_DEFAULT_CXX,
         ".ii",
+        ".mii",
 
         hinters,
 
@@ -790,6 +792,8 @@ namespace build2
       &mxx::static_type,
       &cxx::static_type,
       &c::static_type,
+      &mm::static_type,
+      &m::static_type,
       nullptr
     };
 
@@ -877,6 +881,48 @@ namespace build2
       return true;
     }
 
+    bool
+    objcxx_init (scope& rs,
+                 scope& bs,
+                 const location& loc,
+                 bool,
+                 bool,
+               module_init_extra&)
+    {
+      tracer trace ("cxx::objcxx_init");
+      l5 ([&]{trace << "for " << bs;});
+
+      // We only support root loading (which means there can only be one).
+      //
+      if (rs != bs)
+        fail (loc) << "cxx.objcxx module must be loaded in project root";
+
+      module* mod (rs.find_module<module> ("cxx"));
+
+      if (mod == nullptr)
+        fail (loc) << "cxx.objcxx module must be loaded after cxx module";
+
+      // Register the target type and "enable" it in the module.
+      //
+      // Note that we must register the target type regardless of whether the
+      // C++ compiler is capable of compiling Objective-C++. But we enable
+      // only if it is.
+      //
+      // Note: see similar code in the c module.
+      //
+      rs.insert_target_type<mm> ();
+
+      // Note that while Objective-C++ is supported by MinGW GCC, it's
+      // unlikely Clang supports it when targeting MSVC or Emscripten. But
+      // let's keep the check simple for now.
+      //
+      if (mod->ctype == compiler_type::gcc ||
+          mod->ctype == compiler_type::clang)
+        mod->x_obj = &mm::static_type;
+
+      return true;
+    }
+
     static const module_functions mod_functions[] =
     {
       // NOTE: don't forget to also update the documentation in init.hxx if
@@ -885,6 +931,7 @@ namespace build2
       {"cxx.guess",  nullptr, guess_init},
       {"cxx.config", nullptr, config_init},
       {"cxx",        nullptr, init},
+      {"cxx.objcxx", nullptr, objcxx_init},
       {nullptr,      nullptr, nullptr}
     };
 
diff --git a/libbuild2/cxx/init.hxx b/libbuild2/cxx/init.hxx
index 094fea4..0e42cbe 100644
--- a/libbuild2/cxx/init.hxx
+++ b/libbuild2/cxx/init.hxx
@@ -22,6 +22,8 @@ namespace build2
     // `cxx.guess`  -- registers and sets some variables.
     // `cxx.config` -- loads cxx.guess and sets more variables.
     // `cxx`        -- loads cxx.config and registers target types and rules.
+    // `cxx.objcxx` -- registers mm{} target type and enables Objective-C++
+    //                 compilation.
     //
     extern "C" LIBBUILD2_CXX_SYMEXPORT const module_functions*
     build2_cxx_load ();
diff --git a/libbuild2/cxx/target.cxx b/libbuild2/cxx/target.cxx
index fc50f67..5ead620 100644
--- a/libbuild2/cxx/target.cxx
+++ b/libbuild2/cxx/target.cxx
@@ -3,10 +3,6 @@
 
 #include <libbuild2/cxx/target.hxx>
 
-#include <libbuild2/context.hxx>
-
-using namespace std;
-
 namespace build2
 {
   namespace cxx
@@ -80,5 +76,19 @@ namespace build2
       &file_search,
       target_type::flag::none
     };
+
+    extern const char mm_ext_def[] = "mm";
+    const target_type mm::static_type
+    {
+      "mm",
+      &cc::static_type,
+      &target_factory<mm>,
+      nullptr, /* fixed_extension */
+      &target_extension_var<mm_ext_def>,
+      &target_pattern_var<mm_ext_def>,
+      nullptr,
+      &file_search,
+      target_type::flag::none
+    };
   }
 }
diff --git a/libbuild2/cxx/target.hxx b/libbuild2/cxx/target.hxx
index b20bf00..fc85f75 100644
--- a/libbuild2/cxx/target.hxx
+++ b/libbuild2/cxx/target.hxx
@@ -18,6 +18,7 @@ namespace build2
   {
     using cc::h;
     using cc::c;
+    using cc::m;
 
     class LIBBUILD2_CXX_SYMEXPORT hxx: public cc::cc
     {
@@ -88,6 +89,21 @@ namespace build2
     public:
       static const target_type static_type;
     };
+
+    // Objective-C++ source file.
+    //
+    class LIBBUILD2_CXX_SYMEXPORT mm: public cc::cc
+    {
+    public:
+      mm (context& c, dir_path d, dir_path o, string n)
+        : cc (c, move (d), move (o), move (n))
+      {
+        dynamic_type = &static_type;
+      }
+
+    public:
+      static const target_type static_type;
+    };
   }
 }
 
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