Move cxx build system module to separate library

19 files changed, 211 insertions, 91 deletions

diff --git a/bootstrap-mingw.bat b/bootstrap-mingw.bat
index 43cc84f..128bf58 100644
--- a/bootstrap-mingw.bat
+++ b/bootstrap-mingw.bat
@@ -61,7 +61,6 @@ if "_%libbutl%_" == "__" (
 rem All the source directories.
 rem
 set "src=build2"
-set "src=%src% build2\cxx"
 
 set "src=%src% libbuild2"
 set "src=%src% libbuild2\config"
@@ -72,6 +71,7 @@ set "src=%src% libbuild2\install"
 set "src=%src% libbuild2\bin"
 set "src=%src% libbuild2\c"
 set "src=%src% libbuild2\cc"
+set "src=%src% libbuild2\cxx"
 set "src=%src% libbuild2\version"
 set "src=%src% libbuild2\in"
 
diff --git a/bootstrap-msvc.bat b/bootstrap-msvc.bat
index 8da8769..1c860a2 100644
--- a/bootstrap-msvc.bat
+++ b/bootstrap-msvc.bat
@@ -92,7 +92,6 @@ if "_%libbutl%_" == "__" (
 rem All the source directories.
 rem
 set "src=build2"
-set "src=%src% build2\cxx"
 
 set "src=%src% libbuild2"
 set "src=%src% libbuild2\config"
@@ -103,6 +102,7 @@ set "src=%src% libbuild2\install"
 set "src=%src% libbuild2\bin"
 set "src=%src% libbuild2\c"
 set "src=%src% libbuild2\cc"
+set "src=%src% libbuild2\cxx"
 set "src=%src% libbuild2\version"
 set "src=%src% libbuild2\in"
 
diff --git a/bootstrap.gmake b/bootstrap.gmake
index 0e3126e..0587004 100644
--- a/bootstrap.gmake
+++ b/bootstrap.gmake
@@ -129,9 +129,6 @@ endif
 #
 # Note: list nested subdirectories first (used in clean).
 #
-build2_sub := \
-cxx
-
 libbuild2_sub := \
 config           \
 dist             \
@@ -141,11 +138,11 @@ install          \
 bin              \
 c                \
 cc               \
+cxx              \
 version          \
 in
 
 build2_src    := $(wildcard $(src_root)/build2/*.cxx)
-build2_src    += $(foreach d,$(build2_sub),$(wildcard $(src_root)/build2/$d/*.cxx))
 libbuild2_src := $(wildcard $(src_root)/libbuild2/*.cxx)
 libbuild2_src += $(foreach d,$(libbuild2_sub),$(wildcard $(src_root)/libbuild2/$d/*.cxx))
 libbutl_src   := $(wildcard $(libbutl)/libbutl/*.cxx)
@@ -196,5 +193,5 @@ cleano:
 clean: cleano
 	rm -f $(out_root)/build2/b-boot$(exe)
 ifeq ($(in_tree),false)
-	rm -fd $(foreach d,$(build2_sub),$(out_root)/build2/$d) $(out_root)/build2 $(foreach d,$(libbuild2_sub),$(out_root)/libbuild2/$d) $(out_root)/libbuild2 $(libbutl_out)
+	rm -fd $(out_root)/build2 $(foreach d,$(libbuild2_sub),$(out_root)/libbuild2/$d) $(out_root)/libbuild2 $(libbutl_out)
 endif
diff --git a/bootstrap.sh b/bootstrap.sh
index 368a549..753f538 100755
--- a/bootstrap.sh
+++ b/bootstrap.sh
@@ -117,7 +117,6 @@ if test -z "$libbutl"; then
 fi
 
 src="build2/*.cxx"
-src="$src build2/cxx/*.cxx"
 
 src="$src libbuild2/*.cxx"
 src="$src libbuild2/config/*.cxx"
@@ -128,6 +127,7 @@ src="$src libbuild2/install/*.cxx"
 src="$src libbuild2/bin/*.cxx"
 src="$src libbuild2/c/*.cxx"
 src="$src libbuild2/cc/*.cxx"
+src="$src libbuild2/cxx/*.cxx"
 src="$src libbuild2/version/*.cxx"
 src="$src libbuild2/in/*.cxx"
 
diff --git a/build2/b.cxx b/build2/b.cxx
index 1fd6b5a..a4e799c 100644
--- a/build2/b.cxx
+++ b/build2/b.cxx
@@ -56,6 +56,7 @@
 #include <libbuild2/bin/init.hxx>
 #include <libbuild2/c/init.hxx>
 #include <libbuild2/cc/init.hxx>
+#include <libbuild2/cxx/init.hxx>
 #include <libbuild2/version/init.hxx>
 
 #ifndef BUILD2_BOOTSTRAP
@@ -64,8 +65,6 @@
 #  include <build2/cli/init.hxx>
 #endif
 
-#include <build2/cxx/init.hxx>
-
 using namespace butl;
 using namespace std;
 
@@ -522,13 +521,10 @@ main (int argc, char* argv[])
       load (&bin::build2_bin_load);
       load (&cc::build2_cc_load);
       load (&c::build2_c_load);
+      load (&cxx::build2_cxx_load);
       load (&version::build2_version_load);
       load (&in::build2_in_load);
 
-      TMP_LOAD (cxx_guess, "cxx.guess", cxx::guess_init);
-      TMP_LOAD (cxx_config, "cxx.config", cxx::config_init);
-      TMP_LOAD (cxx, "cxx", cxx::init);
-
 #ifndef BUILD2_BOOTSTRAP
       TMP_LOAD (cli_config, "cli.config", cli::config_init);
       TMP_LOAD (cli, "cli", cli::init);
diff --git a/build2/buildfile b/build2/buildfile
index 7f4187e..fd9cec6 100644
--- a/build2/buildfile
+++ b/build2/buildfile
@@ -7,7 +7,7 @@ import libs = libbutl%lib{butl}
 include ../libbuild2/
 libs += ../libbuild2/lib{build2}
 
-for m: bash bin c cc in version
+for m: bash bin c cc cxx in version
 {
   include ../libbuild2/$m/
   libs += ../libbuild2/$m/lib{build2-$m}
@@ -43,15 +43,6 @@ for t: cxx{**.test...}
 #
 obj{b}: cxx.poptions += -DBUILD2_HOST_TRIPLET=\"$cxx.target\"
 
-# Pass native C and C++ compiler paths (not forgetting to escape backslashes
-# on Windows). These are used as defaults for BUILD2_DEFAULT_*.
-#
-if ($cxx.target == $build.host)
-{
-  cxx/obj{init}: cxx.poptions += \
-    -DBUILD2_NATIVE_CXX=\"$regex.replace($recall($cxx.path), '\\', '\\\\')\"
-}
-
 if ($cxx.target.class != 'windows')
 {
   if ($cxx.target.class == 'linux')
diff --git a/build2/cli/init.cxx b/build2/cli/init.cxx
index 3aebe8e..7b7a519 100644
--- a/build2/cli/init.cxx
+++ b/build2/cli/init.cxx
@@ -11,7 +11,7 @@
 
 #include <libbuild2/config/utility.hxx>
 
-#include <build2/cxx/target.hxx>
+#include <libbuild2/cxx/target.hxx>
 
 #include <build2/cli/target.hxx>
 #include <build2/cli/rule.hxx>
diff --git a/build2/cli/target.hxx b/build2/cli/target.hxx
index c6aa266..cf66a44 100644
--- a/build2/cli/target.hxx
+++ b/build2/cli/target.hxx
@@ -10,7 +10,7 @@
 
 #include <libbuild2/target.hxx>
 
-#include <build2/cxx/target.hxx>
+#include <libbuild2/cxx/target.hxx>
 
 namespace build2
 {
diff --git a/build2/cxx/init.hxx b/build2/cxx/init.hxx
deleted file mode 100644
index 83553e6..0000000
--- a/build2/cxx/init.hxx
+++ /dev/null
@@ -1,46 +0,0 @@
-// file      : build2/cxx/init.hxx -*- C++ -*-
-// copyright : Copyright (c) 2014-2019 Code Synthesis Ltd
-// license   : MIT; see accompanying LICENSE file
-
-#ifndef BUILD2_CXX_INIT_HXX
-#define BUILD2_CXX_INIT_HXX
-
-#include <libbuild2/types.hxx>
-#include <libbuild2/utility.hxx>
-
-#include <libbuild2/module.hxx>
-
-namespace build2
-{
-  namespace cxx
-  {
-    bool
-    guess_init (scope&,
-                scope&,
-                const location&,
-                unique_ptr<module_base>&,
-                bool,
-                bool,
-                const variable_map&);
-
-    bool
-    config_init (scope&,
-                 scope&,
-                 const location&,
-                 unique_ptr<module_base>&,
-                 bool,
-                 bool,
-                 const variable_map&);
-
-    bool
-    init (scope&,
-          scope&,
-          const location&,
-          unique_ptr<module_base>&,
-          bool,
-          bool,
-          const variable_map&);
-  }
-}
-
-#endif // BUILD2_CXX_INIT_HXX
diff --git a/libbuild2/buildfile b/libbuild2/buildfile
index 75731fc..8d40c28 100644
--- a/libbuild2/buildfile
+++ b/libbuild2/buildfile
@@ -2,10 +2,10 @@
 # copyright : Copyright (c) 2014-2019 Code Synthesis Ltd
 # license   : MIT; see accompanying LICENSE file
 
-# NOTE: remember to update bundled_modules in libbuild2/modules.cxx if adding
-#       a new module.
+# NOTE: remember to update bundled_modules in libbuild2/module.cxx if adding a
+#       new module.
 #
-./: lib{build2} bash/ bin/ c/ cc/ in/ version/
+./: lib{build2} bash/ bin/ c/ cc/ cxx/ in/ version/
 
 import int_libs = libbutl%lib{butl}
 
@@ -88,7 +88,7 @@ cross = ($cxx.target.cpu != $build.host.cpu || \
 
 if! $cross
   obj{context}: cxx.poptions += \
-    "-DBUILD2_IMPORT_PATH=\"$regex.replace($out_root, '\\', '\\\\')\""
+    -DBUILD2_IMPORT_PATH=\"$regex.replace($out_root, '\\', '\\\\')\"
 
 obja{context}: cxx.poptions += -DLIBBUILD2_STATIC_BUILD
 objs{context}: cxx.poptions += -DLIBBUILD2_SHARED_BUILD
diff --git a/libbuild2/cxx/buildfile b/libbuild2/cxx/buildfile
new file mode 100644
index 0000000..debb574
--- /dev/null
+++ b/libbuild2/cxx/buildfile
@@ -0,0 +1,90 @@
+# file      : libbuild2/cxx/buildfile
+# copyright : Copyright (c) 2014-2019 Code Synthesis Ltd
+# license   : MIT; see accompanying LICENSE file
+
+import int_libs = libbutl%lib{butl}
+
+include ../
+int_libs += ../lib{build2}
+
+include ../cc/
+int_libs += ../cc/lib{build2-cc}
+
+./: lib{build2-cxx}: libul{build2-cxx}: {hxx ixx txx cxx}{** -**.test...} \
+  $int_libs
+
+# Unit tests.
+#
+exe{*.test}:
+{
+  test = true
+  install = false
+}
+
+for t: cxx{**.test...}
+{
+  d = $directory($t)
+  n = $name($t)...
+
+  ./: $d/exe{$n}: $t $d/{hxx ixx txx}{+$n} $d/testscript{+$n}
+  $d/exe{$n}: libul{build2-cxx}: bin.whole = false
+}
+
+# Build options.
+#
+obja{*}: cxx.poptions += -DLIBBUILD2_CXX_STATIC_BUILD
+objs{*}: cxx.poptions += -DLIBBUILD2_CXX_SHARED_BUILD
+
+# Note that we used to compare complete target triplets but that proved too
+# strict (see libbuild2/buildfile for details).
+#
+cross = ($cxx.target.cpu != $build.host.cpu || \
+         $cxx.target.system != $build.host.system)
+
+# Pass native C++ compiler path (not forgetting to escape backslashes on
+# Windows). It is used as defaults for BUILD2_DEFAULT_CXX.
+#
+if! $cross
+{
+  obj{init}: cxx.poptions += \
+    -DBUILD2_NATIVE_CXX=\"$regex.replace($recall($cxx.path), '\\', '\\\\')\"
+
+  obja{init}: cxx.poptions += -DLIBBUILD2_CXX_STATIC_BUILD
+  objs{init}: cxx.poptions += -DLIBBUILD2_CXX_SHARED_BUILD
+}
+
+# Export options.
+#
+lib{build2-cxx}:
+{
+  cxx.export.poptions = "-I$out_root" "-I$src_root"
+  cxx.export.libs = $int_libs
+}
+
+liba{build2-cxx}: cxx.export.poptions += -DLIBBUILD2_CXX_STATIC
+libs{build2-cxx}: cxx.export.poptions += -DLIBBUILD2_CXX_SHARED
+
+# For pre-releases use the complete version to make sure they cannot be used
+# in place of another pre-release or the final version. See the version module
+# for details on the version.* variable values.
+#
+# And because this is a build system module, we also embed the same value as
+# the interface version (note that we cannot use build.version.interface for
+# bundled modules because we could be built with a different version of the
+# build system).
+#
+ver = ($version.pre_release    \
+       ? "$version.project_id" \
+       : "$version.major.$version.minor")
+
+lib{build2-cxx}: bin.lib.version = @"-$ver"
+libs{build2-cxx}: bin.lib.load_suffix = "-$ver"
+
+# Install into the libbuild2/cxx/ subdirectory of, say, /usr/include/
+# recreating subdirectories.
+#
+{hxx ixx txx}{*}:
+{
+  install         = include/libbuild2/cxx/
+  install.subdirs = true
+}
diff --git a/libbuild2/cxx/export.hxx b/libbuild2/cxx/export.hxx
new file mode 100644
index 0000000..64df2f7
--- /dev/null
+++ b/libbuild2/cxx/export.hxx
@@ -0,0 +1,38 @@
+// file      : libbuild2/cxx/export.hxx -*- C++ -*-
+// copyright : Copyright (c) 2014-2019 Code Synthesis Ltd
+// license   : MIT; see accompanying LICENSE file
+
+#pragma once
+
+// Normally we don't export class templates (but do complete specializations),
+// inline functions, and classes with only inline member functions. Exporting
+// classes that inherit from non-exported/imported bases (e.g., std::string)
+// will end up badly. The only known workarounds are to not inherit or to not
+// export. Also, MinGW GCC doesn't like seeing non-exported functions being
+// used before their inline definition. The workaround is to reorder code. In
+// the end it's all trial and error.
+
+#if defined(LIBBUILD2_CXX_STATIC)         // Using static.
+#  define LIBBUILD2_CXX_SYMEXPORT
+#elif defined(LIBBUILD2_CXX_STATIC_BUILD) // Building static.
+#  define LIBBUILD2_CXX_SYMEXPORT
+#elif defined(LIBBUILD2_CXX_SHARED)       // Using shared.
+#  ifdef _WIN32
+#    define LIBBUILD2_CXX_SYMEXPORT __declspec(dllimport)
+#  else
+#    define LIBBUILD2_CXX_SYMEXPORT
+#  endif
+#elif defined(LIBBUILD2_CXX_SHARED_BUILD) // Building shared.
+#  ifdef _WIN32
+#    define LIBBUILD2_CXX_SYMEXPORT __declspec(dllexport)
+#  else
+#    define LIBBUILD2_CXX_SYMEXPORT
+#  endif
+#else
+// If none of the above macros are defined, then we assume we are being used
+// by some third-party build system that cannot/doesn't signal the library
+// type. Note that this fallback works for both static and shared but in case
+// of shared will be sub-optimal compared to having dllimport.
+//
+#  define LIBBUILD2_CXX_SYMEXPORT         // Using static or shared.
+#endif
diff --git a/build2/cxx/init.cxx b/libbuild2/cxx/init.cxx
index fefa7b9..24d2cb9 100644
--- a/build2/cxx/init.cxx
+++ b/libbuild2/cxx/init.cxx
@@ -1,8 +1,8 @@
-// file      : build2/cxx/init.cxx -*- C++ -*-
+// file      : libbuild2/cxx/init.cxx -*- C++ -*-
 // copyright : Copyright (c) 2014-2019 Code Synthesis Ltd
 // license   : MIT; see accompanying LICENSE file
 
-#include <build2/cxx/init.hxx>
+#include <libbuild2/cxx/init.hxx>
 
 #include <libbuild2/scope.hxx>
 #include <libbuild2/diagnostics.hxx>
@@ -10,7 +10,7 @@
 #include <libbuild2/cc/guess.hxx>
 #include <libbuild2/cc/module.hxx>
 
-#include <build2/cxx/target.hxx>
+#include <libbuild2/cxx/target.hxx>
 
 #ifndef BUILD2_DEFAULT_CXX
 #  ifdef BUILD2_NATIVE_CXX
@@ -625,5 +625,22 @@ namespace build2
       m->init (rs, loc, hints);
       return true;
     }
+
+    static const module_functions mod_functions[] =
+    {
+      // NOTE: don't forget to also update the documentation in init.hxx if
+      //       changing anything here.
+
+      {"cxx.guess",  nullptr, guess_init},
+      {"cxx.config", nullptr, config_init},
+      {"cxx",        nullptr, init},
+      {nullptr,      nullptr, nullptr}
+    };
+
+    const module_functions*
+    build2_cxx_load ()
+    {
+      return mod_functions;
+    }
   }
 }
diff --git a/libbuild2/cxx/init.hxx b/libbuild2/cxx/init.hxx
new file mode 100644
index 0000000..a6398de
--- /dev/null
+++ b/libbuild2/cxx/init.hxx
@@ -0,0 +1,32 @@
+// file      : libbuild2/cxx/init.hxx -*- C++ -*-
+// copyright : Copyright (c) 2014-2019 Code Synthesis Ltd
+// license   : MIT; see accompanying LICENSE file
+
+#ifndef LIBBUILD2_CXX_INIT_HXX
+#define LIBBUILD2_CXX_INIT_HXX
+
+#include <libbuild2/types.hxx>
+#include <libbuild2/utility.hxx>
+
+#include <libbuild2/module.hxx>
+
+#include <libbuild2/cxx/export.hxx>
+
+namespace build2
+{
+  namespace cxx
+  {
+    // Module `cxx` does not require bootstrapping.
+    //
+    // Submodules:
+    //
+    // `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.
+    //
+    extern "C" LIBBUILD2_CXX_SYMEXPORT const module_functions*
+    build2_cxx_load ();
+  }
+}
+
+#endif // LIBBUILD2_CXX_INIT_HXX
diff --git a/build2/cxx/target.cxx b/libbuild2/cxx/target.cxx
index 45463f3..25dfa3a 100644
--- a/build2/cxx/target.cxx
+++ b/libbuild2/cxx/target.cxx
@@ -1,8 +1,8 @@
-// file      : build2/cxx/target.cxx -*- C++ -*-
+// file      : libbuild2/cxx/target.cxx -*- C++ -*-
 // copyright : Copyright (c) 2014-2019 Code Synthesis Ltd
 // license   : MIT; see accompanying LICENSE file
 
-#include <build2/cxx/target.hxx>
+#include <libbuild2/cxx/target.hxx>
 
 #include <libbuild2/context.hxx>
 
diff --git a/build2/cxx/target.hxx b/libbuild2/cxx/target.hxx
index 40dd810..3cf2882 100644
--- a/build2/cxx/target.hxx
+++ b/libbuild2/cxx/target.hxx
@@ -1,9 +1,9 @@
-// file      : build2/cxx/target.hxx -*- C++ -*-
+// file      : libbuild2/cxx/target.hxx -*- C++ -*-
 // copyright : Copyright (c) 2014-2019 Code Synthesis Ltd
 // license   : MIT; see accompanying LICENSE file
 
-#ifndef BUILD2_CXX_TARGET_HXX
-#define BUILD2_CXX_TARGET_HXX
+#ifndef LIBBUILD2_CXX_TARGET_HXX
+#define LIBBUILD2_CXX_TARGET_HXX
 
 #include <libbuild2/types.hxx>
 #include <libbuild2/utility.hxx>
@@ -11,6 +11,8 @@
 #include <libbuild2/target.hxx>
 #include <libbuild2/cc/target.hxx>
 
+#include <libbuild2/cxx/export.hxx>
+
 namespace build2
 {
   namespace cxx
@@ -18,7 +20,7 @@ namespace build2
     using cc::h;
     using cc::c;
 
-    class hxx: public cc::cc
+    class LIBBUILD2_CXX_SYMEXPORT hxx: public cc::cc
     {
     public:
       using cc::cc;
@@ -28,7 +30,7 @@ namespace build2
       virtual const target_type& dynamic_type () const {return static_type;}
     };
 
-    class ixx: public cc::cc
+    class LIBBUILD2_CXX_SYMEXPORT ixx: public cc::cc
     {
     public:
       using cc::cc;
@@ -38,7 +40,7 @@ namespace build2
       virtual const target_type& dynamic_type () const {return static_type;}
     };
 
-    class txx: public cc::cc
+    class LIBBUILD2_CXX_SYMEXPORT txx: public cc::cc
     {
     public:
       using cc::cc;
@@ -48,7 +50,7 @@ namespace build2
       virtual const target_type& dynamic_type () const {return static_type;}
     };
 
-    class cxx: public cc::cc
+    class LIBBUILD2_CXX_SYMEXPORT cxx: public cc::cc
     {
     public:
       using cc::cc;
@@ -63,7 +65,7 @@ namespace build2
     // support dual use (modules/headers) it could actually be #include'd
     // (and even in both cases e.g., by different codebases).
     //
-    class mxx: public cc::cc
+    class LIBBUILD2_CXX_SYMEXPORT mxx: public cc::cc
     {
     public:
       using cc::cc;
@@ -75,4 +77,4 @@ namespace build2
   }
 }
 
-#endif // BUILD2_CXX_TARGET_HXX
+#endif // LIBBUILD2_CXX_TARGET_HXX
diff --git a/libbuild2/module.cxx b/libbuild2/module.cxx
index 37bc817..5cfb1ec 100644
--- a/libbuild2/module.cxx
+++ b/libbuild2/module.cxx
@@ -41,6 +41,7 @@ namespace build2
     "bin",
     "c",
     "cc",
+    "cxx",
     "in",
     "version"
   };
diff --git a/tests/libbuild2/buildfile b/tests/libbuild2/buildfile
index 1d7faf7..f1104d2 100644
--- a/tests/libbuild2/buildfile
+++ b/tests/libbuild2/buildfile
@@ -4,7 +4,7 @@
 
 import libs = build2%lib{build2}
 
-for m: bash bin c cc in version
+for m: bash bin c cc cxx in version
   import libs += build2%lib{build2-$m}
 
 exe{driver}: {hxx cxx}{*} $libs testscript
diff --git a/tests/libbuild2/driver.cxx b/tests/libbuild2/driver.cxx
index e17cdc5..a14d145 100644
--- a/tests/libbuild2/driver.cxx
+++ b/tests/libbuild2/driver.cxx
@@ -12,6 +12,7 @@
 #include <libbuild2/bin/init.hxx>
 #include <libbuild2/c/init.hxx>
 #include <libbuild2/cc/init.hxx>
+#include <libbuild2/cxx/init.hxx>
 #include <libbuild2/bash/init.hxx>
 #include <libbuild2/version/init.hxx>
 
@@ -28,6 +29,7 @@ main (int, char* argv[])
   bin::build2_bin_load ();
   cc::build2_cc_load ();
   c::build2_c_load ();
+  cxx::build2_cxx_load ();
   version::build2_version_load ();
   in::build2_in_load ();
   bash::build2_bash_load ();