Move bin build system module to separate library

10 files changed, 2673 insertions, 0 deletions

diff --git a/libbuild2/bin/buildfile b/libbuild2/bin/buildfile
new file mode 100644
index 0000000..e490214
--- /dev/null
+++ b/libbuild2/bin/buildfile
@@ -0,0 +1,69 @@
+# file      : libbuild2/bin/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}
+
+./: lib{build2-bin}: libul{build2-bin}: {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-bin}: bin.whole = false
+}
+
+# Build options.
+#
+obja{*}: cxx.poptions += -DLIBBUILD2_BIN_STATIC_BUILD
+objs{*}: cxx.poptions += -DLIBBUILD2_BIN_SHARED_BUILD
+
+# Export options.
+#
+lib{build2-bin}:
+{
+  cxx.export.poptions = "-I$out_root" "-I$src_root"
+  cxx.export.libs = $int_libs
+}
+
+liba{build2-bin}: cxx.export.poptions += -DLIBBUILD2_BIN_STATIC
+libs{build2-bin}: cxx.export.poptions += -DLIBBUILD2_BIN_SHARED
+
+# For pre-releases use the complete version to make sure they cannot be used
+# in place of another pre-release or the final version. See the version module
+# for details on the version.* variable values.
+#
+# And because this is a build system module, we also embed the same value as
+# the interface version (note that we cannot use build.version.interface for
+# bundled modules because we could be built with a different version of the
+# build system).
+#
+ver = ($version.pre_release    \
+       ? "$version.project_id" \
+       : "$version.major.$version.minor")
+
+lib{build2-bin}: bin.lib.version = @"-$ver"
+libs{build2-bin}: bin.lib.load_suffix = "-$ver"
+
+# Install into the libbuild2/bin/ subdirectory of, say, /usr/include/
+# recreating subdirectories.
+#
+{hxx ixx txx}{*}:
+{
+  install         = include/libbuild2/bin/
+  install.subdirs = true
+}
diff --git a/libbuild2/bin/export.hxx b/libbuild2/bin/export.hxx
new file mode 100644
index 0000000..944a756
--- /dev/null
+++ b/libbuild2/bin/export.hxx
@@ -0,0 +1,38 @@
+// file      : libbuild2/bin/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_BIN_STATIC)         // Using static.
+#  define LIBBUILD2_BIN_SYMEXPORT
+#elif defined(LIBBUILD2_BIN_STATIC_BUILD) // Building static.
+#  define LIBBUILD2_BIN_SYMEXPORT
+#elif defined(LIBBUILD2_BIN_SHARED)       // Using shared.
+#  ifdef _WIN32
+#    define LIBBUILD2_BIN_SYMEXPORT __declspec(dllimport)
+#  else
+#    define LIBBUILD2_BIN_SYMEXPORT
+#  endif
+#elif defined(LIBBUILD2_BIN_SHARED_BUILD) // Building shared.
+#  ifdef _WIN32
+#    define LIBBUILD2_BIN_SYMEXPORT __declspec(dllexport)
+#  else
+#    define LIBBUILD2_BIN_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_BIN_SYMEXPORT         // Using static or shared.
+#endif
diff --git a/libbuild2/bin/guess.cxx b/libbuild2/bin/guess.cxx
new file mode 100644
index 0000000..68ef827
--- /dev/null
+++ b/libbuild2/bin/guess.cxx
@@ -0,0 +1,464 @@
+// file      : libbuild2/bin/guess.cxx -*- C++ -*-
+// copyright : Copyright (c) 2014-2019 Code Synthesis Ltd
+// license   : MIT; see accompanying LICENSE file
+
+#include <libbuild2/bin/guess.hxx>
+
+#include <libbuild2/diagnostics.hxx>
+
+using namespace std;
+
+namespace build2
+{
+  namespace bin
+  {
+    struct guess_result
+    {
+      string id;
+      string signature;
+      string checksum;
+      semantic_version version;
+
+      guess_result () = default;
+      guess_result (string&& i, string&& s, semantic_version&& v)
+          : id (move (i)), signature (move (s)), version (move (v)) {}
+
+      bool
+      empty () const {return id.empty ();}
+    };
+
+    // Try to parse a semantic-like version from the specified position.
+    // Return 0-version if the version is invalid.
+    //
+    static inline semantic_version
+    parse_version (const string& s, size_t p = 0, const char* bs = ".-+~ ")
+    {
+      optional<semantic_version> v (parse_semantic_version (s, p, bs));
+      return v ? *v : semantic_version ();
+    }
+
+    ar_info
+    guess_ar (const path& ar, const path* rl, const dir_path& fallback)
+    {
+      tracer trace ("bin::guess_ar");
+
+      process_path arp, rlp;
+      guess_result arr, rlr;
+
+      {
+        auto df = make_diag_frame (
+          [](const diag_record& dr)
+          {
+            dr << info << "use config.bin.ar to override";
+          });
+
+        // Only search in PATH (specifically, omitting the current
+        // executable's directory on Windows).
+        //
+        arp = run_search (ar, true, fallback, true /* path_only */);
+      }
+
+      if (rl != nullptr)
+      {
+        auto df = make_diag_frame (
+          [](const diag_record& dr)
+          {
+            dr << info << "use config.bin.ranlib to override";
+          });
+
+        rlp = run_search (*rl, true, fallback, true /* path_only */);
+      }
+
+      // Binutils, LLVM, and FreeBSD ar/ranlib all recognize the --version
+      // option. While Microsoft's lib.exe doesn't support --version, it only
+      // issues a warning and exits with zero status, printing its usual
+      // banner before that (running lib.exe without any options result in
+      // non-zero exit status -- go figure). So we are going to start with
+      // that.
+      //
+      {
+        auto f = [] (string& l, bool) -> guess_result
+        {
+          // Normally GNU binutils ar --version output has a line that starts
+          // with "GNU ar" and ends with the version. For example:
+          //
+          // "GNU ar (GNU Binutils) 2.26"
+          // "GNU ar (GNU Binutils for Ubuntu) 2.26.1"
+          //
+          // However, some embedded toolchain makers customize this stuff in
+          // all kinds of ways. For example:
+          //
+          // "ppc-vle-ar (HighTec Release HDP-v4.6.6.1-bosch-1.3-3c1e3bc) build on 2017-03-23 (GNU Binutils) 2.20"
+          // "GNU ar version 2.13 (tricore) using BFD version 2.13 (2008-12-10)"
+          //
+          // So let's look for "GNU " and be prepared to find junk instead of
+          // the version.
+          //
+          if (l.find ("GNU ") != string::npos)
+          {
+            semantic_version v (parse_version (l, l.rfind (' ') + 1));
+            return guess_result ("gnu", move (l), move (v));
+          }
+
+          // LLVM ar --version output has a line that starts with
+          // "LLVM version " and ends with the version, for example:
+          //
+          // "LLVM version 3.5.2"
+          // "LLVM version 5.0.0"
+          //
+          if (l.compare (0, 13, "LLVM version ") == 0)
+          {
+            semantic_version v (parse_version (l, l.rfind (' ') + 1));
+            return guess_result ("llvm", move (l), move (v));
+          }
+
+          // FreeBSD ar --verison output starts with "BSD ar " followed by
+          // the version and some extra information, for example:
+          //
+          // "BSD ar 1.1.0 - libarchive 3.1.2"
+          //
+          // We will treat the extra information as the build component.
+          //
+          if (l.compare (0, 7, "BSD ar ") == 0)
+          {
+            semantic_version v (parse_version (l, 7));
+            return guess_result ("bsd", move (l), move (v));
+          }
+
+          // Microsoft lib.exe output starts with "Microsoft (R) " and ends
+          // with a four-component version, for example:
+          //
+          // "Microsoft (R) Library Manager Version 14.00.24215.1"
+          // "Microsoft (R) Library Manager Version 14.14.26428.1"
+          //
+          if (l.compare (0, 14, "Microsoft (R) ") == 0)
+          {
+            semantic_version v (parse_version (l, l.rfind (' ') + 1));
+            return guess_result ("msvc", move (l), move (v));
+          }
+
+          return guess_result ();
+        };
+
+        // Suppress all the errors because we may be trying an unsupported
+        // option. Note that in case of lib.exe we will hash the warning
+        // (yes, it goes to stdout) but that seems harmless.
+        //
+        sha256 cs;
+        arr = run<guess_result> (3, arp, "--version", f, false, false, &cs);
+
+        if (!arr.empty ())
+          arr.checksum = cs.string ();
+      }
+
+      // On Mac OS X (and probably also older BSDs) ar/ranlib doesn't have an
+      // option to display version or help. If we run it without any arguments
+      // it dumps usage and exist with an error status. So we will have to use
+      // that.
+      //
+      if (arr.empty ())
+      {
+        auto f = [] (string& l, bool) -> guess_result
+        {
+          return l.find (" ar ") != string::npos
+            ? guess_result ("generic", move (l), semantic_version ())
+            : guess_result ();
+        };
+
+        // Redirect STDERR to STDOUT and ignore exit status.
+        //
+        sha256 cs;
+        arr = run<guess_result> (3, arp, f, false, true, &cs);
+
+        if (!arr.empty ())
+        {
+          l4 ([&]{trace << "generic ar '" << arr.signature << "'";});
+          arr.checksum = cs.string ();
+        }
+      }
+
+      if (arr.empty ())
+        fail << "unable to guess " << ar << " signature";
+
+      // Now repeat pretty much the same steps for ranlib if requested. We
+      // don't bother with the version assuming it is the same as for ar.
+      //
+      if (rl != nullptr)
+      {
+        // Binutils, LLVM, and FreeBSD.
+        //
+        {
+          auto f = [] (string& l, bool) -> guess_result
+          {
+            // The same story as with ar: normally starts with "GNU ranlib "
+            // but can vary.
+            //
+            if (l.find ("GNU ") != string::npos)
+              return guess_result ("gnu", move (l), semantic_version ());
+
+            // "LLVM version ".
+            //
+            if (l.compare (0, 13, "LLVM version ") == 0)
+              return guess_result ("llvm", move (l), semantic_version ());
+
+            // On FreeBSD we get "ranlib" rather than "BSD ranlib" for some
+            // reason. Which means we can't really call it 'bsd' for sure.
+            //
+            //if (l.compare (0, 7, "ranlib ") == 0)
+            //  return guess_result ("bsd", move (l), semantic_version ());
+
+            return guess_result ();
+          };
+
+          sha256 cs;
+          rlr = run<guess_result> (3, rlp, "--version", f, false, false, &cs);
+
+          if (!rlr.empty ())
+            rlr.checksum = cs.string ();
+        }
+
+        // Mac OS X (and probably also older BSDs).
+        //
+        if (rlr.empty ())
+        {
+          auto f = [] (string& l, bool) -> guess_result
+          {
+            return l.find ("ranlib") != string::npos
+              ? guess_result ("generic", move (l), semantic_version ())
+              : guess_result ();
+          };
+
+          // Redirect STDERR to STDOUT and ignore exit status.
+          //
+          sha256 cs;
+          rlr = run<guess_result> (3, rlp, f, false, true, &cs);
+
+          if (!rlr.empty ())
+          {
+            l4 ([&]{trace << "generic ranlib '" << rlr.signature << "'";});
+            rlr.checksum = cs.string ();
+          }
+        }
+
+        if (rlr.empty ())
+          fail << "unable to guess " << *rl << " signature";
+      }
+
+      return ar_info {
+        move (arp),
+        move (arr.id),
+        move (arr.signature),
+        move (arr.checksum),
+        move (arr.version),
+
+        move (rlp),
+        move (rlr.id),
+        move (rlr.signature),
+        move (rlr.checksum)};
+    }
+
+    ld_info
+    guess_ld (const path& ld, const dir_path& fallback)
+    {
+      tracer trace ("bin::guess_ld");
+
+      guess_result r;
+
+      process_path pp;
+      {
+        auto df = make_diag_frame (
+          [](const diag_record& dr)
+          {
+            dr << info << "use config.bin.ld to override";
+          });
+
+        // Only search in PATH (specifically, omitting the current
+        // executable's directory on Windows).
+        //
+        pp = run_search (ld, true, fallback, true /* path_only */);
+      }
+
+      // Binutils ld recognizes the --version option. Microsoft's link.exe
+      // doesn't support --version (nor any other way to get the version
+      // without the error exit status) but it will still print its banner.
+      // We also want to recognize link.exe as fast as possible since it will
+      // be the most commonly configured linker (for other platoforms the
+      // linker will normally be used indirectly via the compiler and the
+      // bin.ld module won't be loaded). So we are going to ignore the error
+      // exit status. Our signatures are fairly specific to avoid any kind
+      // of false positives.
+      //
+      // Version extraction is a @@ TODO.
+      //
+      {
+        auto f = [] (string& l, bool) -> guess_result
+        {
+          // Microsoft link.exe output starts with "Microsoft (R) ".
+          //
+          if (l.compare (0, 14, "Microsoft (R) ") == 0)
+            return guess_result ("msvc", move (l), semantic_version ());
+
+          // Binutils ld.bfd --version output has a line that starts with
+          // "GNU ld " while ld.gold -- "GNU gold". Again, fortify it against
+          // embedded toolchain customizations by search for "GNU " in the
+          // former case.
+          //
+          if (l.compare (0, 9, "GNU gold ") == 0)
+            return guess_result ("gold", move (l), semantic_version ());
+
+          if (l.find ("GNU ") != string::npos)
+            return guess_result ("gnu", move (l), semantic_version ());
+
+          return guess_result ();
+        };
+
+        // Redirect STDERR to STDOUT and ignore exit status. Note that in case
+        // of link.exe we will hash the diagnostics (yes, it goes to stdout)
+        // but that seems harmless.
+        //
+        sha256 cs;
+        r = run<guess_result> (3, pp, "--version", f, false, true, &cs);
+
+        if (!r.empty ())
+          r.checksum = cs.string ();
+      }
+
+      // Next try -v which will cover Apple's linkers.
+      //
+      if (r.empty ())
+      {
+        auto f = [] (string& l, bool) -> guess_result
+        {
+          // New ld64 has "PROJECT:ld64" in the first line (output to stderr),
+          // for example:
+          //
+          // @(#)PROGRAM:ld  PROJECT:ld64-242.2
+          //
+          if (l.find ("PROJECT:ld64") != string::npos)
+            return guess_result ("ld64", move (l), semantic_version ());
+
+          // Old ld has "cctools" in the first line, for example:
+          //
+          // Apple Computer, Inc. version cctools-622.9~2
+          //
+          if (l.find ("cctools") != string::npos)
+            return guess_result ("cctools", move (l), semantic_version ());
+
+          return guess_result ();
+        };
+
+        sha256 cs;
+        r = run<guess_result> (3, pp, "-v", f, false, false, &cs);
+
+        if (!r.empty ())
+          r.checksum = cs.string ();
+      }
+
+      // Finally try -version which will take care of LLVM's lld.
+      //
+      if (r.empty ())
+      {
+        auto f = [] (string& l, bool) -> guess_result
+        {
+          // Unlike other LLVM tools (e.g., ar), the lld's version is printed
+          // (to stderr) as:
+          //
+          // LLVM Linker Version: 3.7
+          //
+          if (l.compare (0, 19, "LLVM Linker Version") == 0)
+            return guess_result ("llvm", move (l), semantic_version ());
+
+          return guess_result ();
+        };
+
+        // Suppress all the errors because we may be trying an unsupported
+        // option.
+        //
+        sha256 cs;
+        r = run<guess_result> (3, pp, "-version", f, false, false, &cs);
+
+        if (!r.empty ())
+          r.checksum = cs.string ();
+      }
+
+      if (r.empty ())
+        fail << "unable to guess " << ld << " signature";
+
+      return ld_info {
+        move (pp), move (r.id), move (r.signature), move (r.checksum)};
+    }
+
+    rc_info
+    guess_rc (const path& rc, const dir_path& fallback)
+    {
+      tracer trace ("bin::guess_rc");
+
+      guess_result r;
+
+      process_path pp;
+      {
+        auto df = make_diag_frame (
+          [](const diag_record& dr)
+          {
+            dr << info << "use config.bin.rc to override";
+          });
+
+        // Only search in PATH (specifically, omitting the current
+        // executable's directory on Windows).
+        //
+        pp = run_search (rc, true, fallback, true /* path_only */);
+      }
+
+      // Binutils windres recognizes the --version option.
+      //
+      // Version extraction is a @@ TODO.
+      {
+        auto f = [] (string& l, bool) -> guess_result
+        {
+          // Binutils windres --version output has a line that starts with
+          // "GNU windres " but search for "GNU ", similar to other tools.
+          //
+          if (l.find ("GNU ") != string::npos)
+            return guess_result ("gnu", move (l), semantic_version ());
+
+          return guess_result ();
+        };
+
+        // Suppress all the errors because we may be trying an unsupported
+        // option.
+        //
+        sha256 cs;
+        r = run<guess_result> (3, pp, "--version", f, false, false, &cs);
+
+        if (!r.empty ())
+          r.checksum = cs.string ();
+      }
+
+      // Microsoft rc.exe /? prints its standard banner and exits with zero
+      // status.
+      //
+      if (r.empty ())
+      {
+        auto f = [] (string& l, bool) -> guess_result
+        {
+          if (l.compare (0, 14, "Microsoft (R) ") == 0)
+            return guess_result ("msvc", move (l), semantic_version ());
+
+          return guess_result ();
+        };
+
+        sha256 cs;
+        r = run<guess_result> (3, pp, "/?", f, false, false, &cs);
+
+        if (!r.empty ())
+          r.checksum = cs.string ();
+      }
+
+      if (r.empty ())
+        fail << "unable to guess " << rc << " signature";
+
+      return rc_info {
+        move (pp), move (r.id), move (r.signature), move (r.checksum)};
+    }
+  }
+}
diff --git a/libbuild2/bin/guess.hxx b/libbuild2/bin/guess.hxx
new file mode 100644
index 0000000..0e04ba5
--- /dev/null
+++ b/libbuild2/bin/guess.hxx
@@ -0,0 +1,108 @@
+// file      : libbuild2/bin/guess.hxx -*- C++ -*-
+// copyright : Copyright (c) 2014-2019 Code Synthesis Ltd
+// license   : MIT; see accompanying LICENSE file
+
+#ifndef LIBBUILD2_BIN_GUESS_HXX
+#define LIBBUILD2_BIN_GUESS_HXX
+
+#include <libbuild2/types.hxx>
+#include <libbuild2/utility.hxx>
+
+namespace build2
+{
+  namespace bin
+  {
+    // ar/ranlib information.
+    //
+    // Currently recognized ar/ranlib and their ids:
+    //
+    // gnu          GNU binutils
+    // llvm         LLVM
+    // bsd          FreeBSD (and maybe other BSDs)
+    // msvc         Microsoft's lib.exe
+    // generic      Generic/unrecognized
+    //
+    // The signature is normally the --version/-V line.
+    //
+    // The checksum is used to detect ar/ranlib changes. It is calculated in
+    // a toolchain-specific manner (usually the output of --version/-V) and
+    // is not bulletproof.
+    //
+    struct ar_info
+    {
+      process_path ar_path;
+      string ar_id;
+      string ar_signature;
+      string ar_checksum;
+      semantic_version ar_version;
+
+      process_path ranlib_path;
+      string ranlib_id;
+      string ranlib_signature;
+      string ranlib_checksum;
+    };
+
+    // The ranlib path can be NULL, in which case no ranlib guessing will be
+    // attemplated and the returned ranlib_* members will be left empty.
+    //
+    ar_info
+    guess_ar (const path& ar, const path* ranlib, const dir_path& fallback);
+
+    // ld information.
+    //
+    // Currently recognized linkers and their ids:
+    //
+    // gnu          GNU binutils ld.bfd
+    // gold         GNU binutils ld.gold
+    // llvm         LLVM lld (note: not llvm-ld or llvm-link)
+    // ld64         Apple's new linker
+    // cctools      Apple's old/classic linker
+    // msvc         Microsoft's link.exe
+    //
+    // Note that BSDs are currently using GNU ld but some of them (e.g.,
+    // FreeBSD) are hoping to migrate to lld.
+    //
+    // The signature is normally the --version/-version/-v line.
+    //
+    // The checksum is used to detect ld changes. It is calculated in a
+    // toolchain-specific manner (usually the output of --version/-version/-v)
+    // and is not bulletproof.
+    //
+    struct ld_info
+    {
+      process_path path;
+      string id;
+      string signature;
+      string checksum;
+    };
+
+    ld_info
+    guess_ld (const path& ld, const dir_path& fallback);
+
+    // rc information.
+    //
+    // Currently recognized resource compilers and their ids:
+    //
+    // gnu          GNU binutils windres
+    // msvc         Microsoft's rc.exe
+    //
+    // The signature is normally the --version line.
+    //
+    // The checksum is used to detect rc changes. It is calculated in a
+    // toolchain-specific manner (usually the output of --version) and is not
+    // bulletproof.
+    //
+    struct rc_info
+    {
+      process_path path;
+      string id;
+      string signature;
+      string checksum;
+    };
+
+    rc_info
+    guess_rc (const path& rc, const dir_path& fallback);
+  }
+}
+
+#endif // LIBBUILD2_BIN_GUESS_HXX
diff --git a/libbuild2/bin/init.cxx b/libbuild2/bin/init.cxx
new file mode 100644
index 0000000..d56e0a5
--- /dev/null
+++ b/libbuild2/bin/init.cxx
@@ -0,0 +1,963 @@
+// file      : build2/bin/init.cxx -*- C++ -*-
+// copyright : Copyright (c) 2014-2019 Code Synthesis Ltd
+// license   : MIT; see accompanying LICENSE file
+
+#include <libbuild2/bin/init.hxx>
+
+#include <map>
+
+#include <libbuild2/scope.hxx>
+#include <libbuild2/variable.hxx>
+#include <libbuild2/diagnostics.hxx>
+
+#include <libbuild2/config/utility.hxx>
+
+#include <libbuild2/test/module.hxx>
+
+#include <libbuild2/install/rule.hxx>
+#include <libbuild2/install/utility.hxx>
+
+#include <libbuild2/bin/rule.hxx>
+#include <libbuild2/bin/guess.hxx>
+#include <libbuild2/bin/target.hxx>
+
+using namespace std;
+using namespace butl;
+
+namespace build2
+{
+  namespace bin
+  {
+    static const fail_rule fail_;
+    static const lib_rule lib_;
+
+    // Default config.bin.*.lib values.
+    //
+    static const strings exe_lib {"shared", "static"};
+    static const strings liba_lib {"static", "shared"};
+    static const strings libs_lib {"shared", "static"};
+
+    bool
+    vars_init (scope& rs,
+               scope&,
+               const location&,
+               unique_ptr<module_base>&,
+               bool first,
+               bool,
+               const variable_map&)
+    {
+      tracer trace ("bin::vars_init");
+      l5 ([&]{trace << "for " << rs;});
+
+      assert (first);
+
+      // Enter variables. Note: some overridable, some not.
+      //
+      // Target is a string and not target_triplet because it can be
+      // specified by the user.
+      //
+      auto& vp (rs.ctx.var_pool.rw (rs));
+
+      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);
+
+      // 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);
+      vp.insert<string>    ("config.bin.lib.prefix", true);
+      vp.insert<string>    ("config.bin.lib.suffix", true);
+      vp.insert<string>    ("config.bin.exe.prefix", true);
+      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.
+      //
+      // The lookup semantics is as follows: we first look for a prerequisite-
+      // specific value, then for a target-specific value in the library being
+      // linked, and then for target type/pattern-specific value starting from
+      // the scope of the target being linked-to. In that final lookup we do
+      // not look in the target being linked-to itself since that is used to
+      // indicate how this target should be linked to other targets. For
+      // example:
+      //
+      // exe{test}: liba{foo}
+      // liba{foo}: libua{foo1 foo2}
+      // liba{foo}: bin.whole = false # Affects test but not foo1 and foo2.
+      //
+      // If unspecified, defaults to false for liba{} and to true for libu*{}.
+      //
+      vp.insert<bool>      ("bin.whole", false, variable_visibility::target);
+
+      vp.insert<string>    ("bin.exe.prefix");
+      vp.insert<string>    ("bin.exe.suffix");
+      vp.insert<string>    ("bin.lib.prefix");
+      vp.insert<string>    ("bin.lib.suffix");
+
+      vp.insert<string>    ("bin.lib.load_suffix",
+                            variable_visibility::project);
+
+      vp.insert<map<string, string>> ("bin.lib.version",
+                                      variable_visibility::project);
+
+      return true;
+    }
+
+    bool
+    config_init (scope& rs,
+                 scope& bs,
+                 const location& loc,
+                 unique_ptr<module_base>&,
+                 bool first,
+                 bool,
+                 const variable_map& hints)
+    {
+      tracer trace ("bin::config_init");
+      l5 ([&]{trace << "for " << bs;});
+
+      // We only support root loading (which means there can only be one).
+      //
+      if (&rs != &bs)
+        fail (loc) << "bin.config module must be loaded in project root";
+
+      // Load bin.vars.
+      //
+      if (!cast_false<bool> (rs["bin.vars.loaded"]))
+        load_module (rs, rs, "bin.vars", loc);
+
+      // Configure.
+      //
+      using config::required;
+      using config::optional;
+      using config::omitted;
+
+      // Adjust module priority (binutils).
+      //
+      config::save_module (rs, "bin", 350);
+
+      // The idea here is as follows: if we already have one of
+      // the bin.* variables set, then we assume this is static
+      // project configuration and don't bother setting the
+      // corresponding config.bin.* variable.
+      //
+      //@@ Need to validate the values. Would be more efficient
+      //   to do it once on assignment than every time on query.
+      //   Custom var type?
+      //
+
+      // config.bin.lib
+      //
+      {
+        value& v (rs.assign ("bin.lib"));
+        if (!v)
+          v = *required (rs, "config.bin.lib", "both").first;
+      }
+
+      // config.bin.exe.lib
+      //
+      {
+        value& v (rs.assign ("bin.exe.lib"));
+        if (!v)
+          v = *required (rs, "config.bin.exe.lib", exe_lib).first;
+      }
+
+      // config.bin.liba.lib
+      //
+      {
+        value& v (rs.assign ("bin.liba.lib"));
+        if (!v)
+          v = *required (rs, "config.bin.liba.lib", liba_lib).first;
+      }
+
+      // config.bin.libs.lib
+      //
+      {
+        value& v (rs.assign ("bin.libs.lib"));
+        if (!v)
+          v = *required (rs, "config.bin.libs.lib", libs_lib).first;
+      }
+
+      // config.bin.rpath[_link]
+      //
+      // 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
+      // config.build if not specified. We also override any existing value
+      // that might have been specified before loading the module.
+      //
+      {
+        lookup p (omitted (rs, "config.bin.prefix").first);
+        lookup s (omitted (rs, "config.bin.suffix").first);
+
+        auto set = [&rs] (const char* bv, const char* cv, lookup l)
+        {
+          if (lookup o = omitted (rs, cv).first)
+            l = o;
+
+          if (l)
+            rs.assign (bv) = *l;
+        };
+
+        set ("bin.lib.prefix", "config.bin.lib.prefix", p);
+        set ("bin.lib.suffix", "config.bin.lib.suffix", s);
+
+        set ("bin.exe.prefix", "config.bin.exe.prefix", p);
+        set ("bin.exe.suffix", "config.bin.exe.suffix", s);
+      }
+
+      if (first)
+      {
+        bool new_val (false); // Set any new values?
+
+        // config.bin.target
+        //
+        {
+          const variable& var (rs.ctx.var_pool["config.bin.target"]);
+
+          // We first see if the value was specified via the configuration
+          // mechanism.
+          //
+          auto p (omitted (rs, var));
+          lookup l (p.first);
+
+          // Then see if there is a config hint (e.g., from the cc module).
+          //
+          bool hint (false);
+          if (!l)
+          {
+            if (auto hl = hints[var])
+            {
+              l = hl;
+              hint = true;
+            }
+          }
+
+          if (!l)
+            fail (loc) << "unable to determine binutils target" <<
+              info << "consider specifying it with " << var <<
+              info << "or first load a module that can provide it as a hint, "
+                       << "such as c or cxx";
+
+          // Split/canonicalize the target.
+          //
+          string s (cast<string> (l));
+
+          // Did the user ask us to use config.sub? If this is a hinted value,
+          // then we assume it has already been passed through config.sub.
+          //
+          if (!hint && config_sub)
+          {
+            s = run<string> (3,
+                             *config_sub,
+                             s.c_str (),
+                             [] (string& l, bool) {return move (l);});
+            l5 ([&]{trace << "config.sub target: '" << s << "'";});
+          }
+
+          try
+          {
+            target_triplet t (s);
+
+            l5 ([&]{trace << "canonical target: '" << t.string () << "'; "
+                          << "class: " << t.class_;});
+
+            assert (!hint || s == t.string ());
+
+            // Also enter as bin.target.{cpu,vendor,system,version,class}
+            // for convenience of access.
+            //
+            rs.assign<string> ("bin.target.cpu")     = t.cpu;
+            rs.assign<string> ("bin.target.vendor")  = t.vendor;
+            rs.assign<string> ("bin.target.system")  = t.system;
+            rs.assign<string> ("bin.target.version") = t.version;
+            rs.assign<string> ("bin.target.class")   = t.class_;
+
+            rs.assign<target_triplet> ("bin.target") = move (t);
+          }
+          catch (const invalid_argument& e)
+          {
+            // This is where we suggest that the user specifies --config-sub
+            // to help us out.
+            //
+            fail << "unable to parse binutils target '" << s << "': " << e <<
+              info << "consider using the --config-sub option";
+          }
+
+          new_val = new_val || p.second; // False for a hinted value.
+        }
+
+        // config.bin.pattern
+        //
+        {
+          const variable& var (rs.ctx.var_pool["config.bin.pattern"]);
+
+          // We first see if the value was specified via the configuration
+          // mechanism.
+          //
+          auto p (omitted (rs, var));
+          lookup l (p.first);
+
+          // Then see if there is a config hint (e.g., from the C++ module).
+          //
+          if (!l)
+          {
+            if (auto hl = hints[var])
+              l = hl;
+          }
+
+          // For ease of use enter it as bin.pattern (since it can come from
+          // different places).
+          //
+          if (l)
+          {
+            const string& s (cast<string> (l));
+
+            if (s.empty () ||
+                (!path::traits_type::is_separator (s.back ()) &&
+                 s.find ('*') == string::npos))
+            {
+              fail << "missing '*' in binutils pattern '" << s << "'";
+            }
+
+            rs.assign<string> ("bin.pattern") = s;
+            new_val = new_val || p.second; // False for a hinted value.
+          }
+        }
+
+        // If we set any new values (e.g., we are configuring), then print the
+        // report at verbosity level 2 and up (-v).
+        //
+        if (verb >= (new_val ? 2 : 3))
+        {
+          diag_record dr (text);
+
+          dr << "bin " << project (rs) << '@' << rs << '\n'
+             << "  target     " << cast<target_triplet> (rs["bin.target"]);
+
+          if (auto l = rs["bin.pattern"])
+            dr << '\n'
+               << "  pattern    " << cast<string> (l);
+        }
+      }
+
+      return true;
+    }
+
+    bool
+    init (scope& rs,
+          scope& bs,
+          const location& loc,
+          unique_ptr<module_base>&,
+          bool first,
+          bool,
+          const variable_map& hints)
+    {
+      tracer trace ("bin::init");
+      l5 ([&]{trace << "for " << bs;});
+
+      // Load bin.config.
+      //
+      if (!cast_false<bool> (rs["bin.config.loaded"]))
+        load_module (rs, rs, "bin.config", loc, false, hints);
+
+      // Cache some config values we will be needing below.
+      //
+      const string& tclass (cast<string> (rs["bin.target.class"]));
+
+      // Register target types and configure their default "installability".
+      //
+      bool install_loaded (cast_false<bool> (rs["install.loaded"]));
+      {
+        using namespace install;
+
+        if (first)
+        {
+          rs.insert_target_type<obj>  ();
+          rs.insert_target_type<obje> ();
+          rs.insert_target_type<obja> ();
+          rs.insert_target_type<objs> ();
+
+          rs.insert_target_type<bmi>  ();
+          rs.insert_target_type<bmie> ();
+          rs.insert_target_type<bmia> ();
+          rs.insert_target_type<bmis> ();
+
+          rs.insert_target_type<hbmi>  ();
+          rs.insert_target_type<hbmie> ();
+          rs.insert_target_type<hbmia> ();
+          rs.insert_target_type<hbmis> ();
+
+          rs.insert_target_type<libul> ();
+          rs.insert_target_type<libue> ();
+          rs.insert_target_type<libua> ();
+          rs.insert_target_type<libus> ();
+
+          rs.insert_target_type<lib>  ();
+          rs.insert_target_type<liba> ();
+          rs.insert_target_type<libs> ();
+
+          // Register the def{} target type. Note that we do it here since it
+          // is input and can be specified unconditionally (i.e., not only
+          // when building for Windows).
+          //
+          rs.insert_target_type<def> ();
+        }
+
+        // Note: libu*{} members are not installable.
+        //
+        if (install_loaded)
+        {
+          install_path<liba> (bs, dir_path ("lib")); // Install in install.lib.
+          install_mode<liba> (bs, "644");
+        }
+
+        // Should shared libraries have the executable bit? That depends on
+        // who you ask. In Debian, for example, it should not unless, it
+        // really is executable (i.e., has main()). On the other hand, on
+        // some systems, this may be required in order for the dynamic
+        // linker to be able to load the library. So, by default, we will
+        // keep it executable, especially seeing that this is also the
+        // behavior of autotools. At the same time, it is easy to override
+        // this, for example:
+        //
+        // config.install.lib.mode=644
+        //
+        // And a library that wants to override any such overrides (e.g.,
+        // because it does have main()) can do:
+        //
+        // libs{foo}: install.mode=755
+        //
+        // Everyone is happy then? On Windows libs{} is the DLL and goes to
+        // bin/, not lib/.
+        //
+        if (install_loaded)
+          install_path<libs> (bs,
+                              dir_path (tclass == "windows" ? "bin" : "lib"));
+
+        // Create additional target types for certain targets.
+        //
+        if (tclass == "windows")
+        {
+          // Import library.
+          //
+          if (first)
+            rs.insert_target_type<libi> ();
+
+          if (install_loaded)
+          {
+            install_path<libi> (bs, dir_path ("lib"));
+            install_mode<libi> (bs, "644");
+          }
+        }
+      }
+
+      // Register rules.
+      //
+      {
+        auto& r (bs.rules);
+
+        r.insert<obj> (perform_update_id, "bin.obj", fail_);
+        r.insert<obj> (perform_clean_id,  "bin.obj", fail_);
+
+        r.insert<bmi> (perform_update_id, "bin.bmi", fail_);
+        r.insert<bmi> (perform_clean_id,  "bin.bmi", fail_);
+
+        r.insert<hbmi> (perform_update_id, "bin.hbmi", fail_);
+        r.insert<hbmi> (perform_clean_id,  "bin.hbmi", fail_);
+
+        r.insert<libul> (perform_update_id, "bin.libul", fail_);
+        r.insert<libul> (perform_clean_id,  "bin.libul", fail_);
+
+        // Similar to alias.
+        //
+
+        //@@ outer
+        r.insert<lib> (perform_id, 0, "bin.lib", lib_);
+        r.insert<lib> (configure_id, 0, "bin.lib", lib_);
+
+        // Treat as a see through group for install and test.
+        //
+        if (install_loaded)
+        {
+          auto& gr (install::group_rule::instance);
+
+          r.insert<lib> (perform_install_id, "bin.lib", gr);
+          r.insert<lib> (perform_uninstall_id, "bin.lib", gr);
+        }
+
+        if (const test::module* m = rs.lookup_module<test::module> ("test"))
+        {
+          r.insert<lib> (perform_test_id, "bin.lib", m->group_rule ());
+        }
+      }
+
+      return true;
+    }
+
+    bool
+    ar_config_init (scope& rs,
+                    scope& bs,
+                    const location& loc,
+                    unique_ptr<module_base>&,
+                    bool first,
+                    bool,
+                    const variable_map& hints)
+    {
+      tracer trace ("bin::ar_config_init");
+      l5 ([&]{trace << "for " << bs;});
+
+      // Make sure bin.config is loaded.
+      //
+      if (!cast_false<bool> (rs["bin.config.loaded"]))
+        load_module (rs, bs, "bin.config", loc, false, hints);
+
+      // Enter configuration variables.
+      //
+      if (first)
+      {
+        auto& v (rs.ctx.var_pool.rw (rs));
+
+        v.insert<process_path> ("bin.ar.path");
+        v.insert<process_path> ("bin.ranlib.path");
+
+        v.insert<path>         ("config.bin.ar", true);
+        v.insert<path>         ("config.bin.ranlib", true);
+      }
+
+      // Configure.
+      //
+      if (first)
+      {
+        // config.bin.ar
+        // config.bin.ranlib
+        //
+        // For config.bin.ar we have the default (plus the pattern) while
+        // ranlib should be explicitly specified by the user in order for us
+        // to use it (all targets that we currently care to support have the
+        // ar -s option but if that changes we can always force the use of
+        // ranlib for certain targets).
+        //
+        // Another idea is to refuse to use default 'ar' (without the pattern)
+        // if the host/build targets don't match. On the other hand, a cross-
+        // toolchain can be target-unprefixed. Also, without canonicalization,
+        // comparing targets will be unreliable.
+        //
+
+        // Use the target to decide on the default binutils program names.
+        //
+        const string& tsys (cast<string> (rs["bin.target.system"]));
+        const char* ar_d (tsys == "win32-msvc" ? "lib" : "ar");
+
+        // This can be either a pattern or a fallback search directory.
+        //
+        const string* pat (cast_null<string> (rs["bin.pattern"]));
+
+        bool fb (pat != nullptr &&
+                 path::traits_type::is_separator (pat->back ()));
+
+        // Don't save the default value to config.build so that if the user
+        // changes, say, the C++ compiler (which hinted the pattern), then
+        // ar will automatically change as well.
+        //
+        auto ap (
+          config::required (
+            rs,
+            "config.bin.ar",
+            path (apply_pattern (ar_d, fb ? nullptr : pat)),
+            false,
+            config::save_commented));
+
+        auto rp (
+          config::required (
+            rs,
+            "config.bin.ranlib",
+            nullptr,
+            false,
+            config::save_commented));
+
+        const path& ar (cast<path> (ap.first));
+        const path* ranlib (cast_null<path> (rp.first));
+
+        ar_info ari (
+          guess_ar (ar, ranlib, fb ? dir_path (*pat) : dir_path ()));
+
+        // If this is a new value (e.g., we are configuring), then print the
+        // report at verbosity level 2 and up (-v).
+        //
+        if (verb >= (ap.second || rp.second ? 2 : 3))
+        {
+          diag_record dr (text);
+
+          {
+            dr << "bin.ar " << project (rs) << '@' << rs << '\n'
+               << "  ar         " << ari.ar_path << '\n'
+               << "  id         " << ari.ar_id << '\n'
+               << "  version    " << ari.ar_version.string () << '\n'
+               << "  major      " << ari.ar_version.major << '\n'
+               << "  minor      " << ari.ar_version.minor << '\n'
+               << "  patch      " << ari.ar_version.patch << '\n';
+          }
+
+          if (!ari.ar_version.build.empty ())
+          {
+            dr << "  build      " << ari.ar_version.build << '\n';
+          }
+
+          {
+            dr << "  signature  " << ari.ar_signature << '\n'
+               << "  checksum   " << ari.ar_checksum;
+          }
+
+          if (ranlib != nullptr)
+          {
+            dr << '\n'
+               << "  ranlib     " << ari.ranlib_path << '\n'
+               << "  id         " << ari.ranlib_id << '\n'
+               << "  signature  " << ari.ranlib_signature << '\n'
+               << "  checksum   " << ari.ranlib_checksum;
+          }
+        }
+
+        rs.assign<process_path> ("bin.ar.path")      = move (ari.ar_path);
+        rs.assign<string>       ("bin.ar.id")        = move (ari.ar_id);
+        rs.assign<string>       ("bin.ar.signature") = move (ari.ar_signature);
+        rs.assign<string>       ("bin.ar.checksum")  = move (ari.ar_checksum);
+
+        {
+          semantic_version& v (ari.ar_version);
+
+          rs.assign<string>   ("bin.ar.version")       = v.string ();
+          rs.assign<uint64_t> ("bin.ar.version.major") = v.major;
+          rs.assign<uint64_t> ("bin.ar.version.minor") = v.minor;
+          rs.assign<uint64_t> ("bin.ar.version.patch") = v.patch;
+          rs.assign<string>   ("bin.ar.version.build") = move (v.build);
+        }
+
+        if (ranlib != nullptr)
+        {
+          rs.assign<process_path> ("bin.ranlib.path") = move (ari.ranlib_path);
+          rs.assign<string>       ("bin.ranlib.id")   = move (ari.ranlib_id);
+          rs.assign<string>       ("bin.ranlib.signature") =
+            move (ari.ranlib_signature);
+          rs.assign<string>       ("bin.ranlib.checksum") =
+            move (ari.ranlib_checksum);
+        }
+      }
+
+      return true;
+    }
+
+    bool
+    ar_init (scope& rs,
+             scope& bs,
+             const location& loc,
+             unique_ptr<module_base>&,
+             bool,
+             bool,
+             const variable_map& hints)
+    {
+      tracer trace ("bin::ar_init");
+      l5 ([&]{trace << "for " << bs;});
+
+      // Make sure the bin core and ar.config are loaded.
+      //
+      if (!cast_false<bool> (bs["bin.loaded"]))
+        load_module (rs, bs, "bin", loc, false, hints);
+
+      if (!cast_false<bool> (bs["bin.ar.config.loaded"]))
+        load_module (rs, bs, "bin.ar.config", loc, false, hints);
+
+      return true;
+    }
+
+    bool
+    ld_config_init (scope& rs,
+                    scope& bs,
+                    const location& loc,
+                    unique_ptr<module_base>&,
+                    bool first,
+                    bool,
+                    const variable_map& hints)
+    {
+      tracer trace ("bin::ld_config_init");
+      l5 ([&]{trace << "for " << bs;});
+
+      // Make sure bin.config is loaded.
+      //
+      if (!cast_false<bool> (rs["bin.config.loaded"]))
+        load_module (rs, rs, "bin.config", loc, false, hints);
+
+      // Enter configuration variables.
+      //
+      if (first)
+      {
+        auto& v (rs.ctx.var_pool.rw (rs));
+
+        v.insert<process_path> ("bin.ld.path");
+        v.insert<path>         ("config.bin.ld", true);
+      }
+
+      // Configure.
+      //
+      if (first)
+      {
+        // config.bin.ld
+        //
+        // Use the target to decide on the default ld name.
+        //
+        const string& tsys (cast<string> (rs["bin.target.system"]));
+        const char* ld_d (tsys == "win32-msvc" ? "link" : "ld");
+
+        // This can be either a pattern or a fallback search directory.
+        //
+        const string* pat (cast_null<string> (rs["bin.pattern"]));
+
+        bool fb (pat != nullptr &&
+                 path::traits_type::is_separator (pat->back ()));
+
+        auto p (
+          config::required (
+            rs,
+            "config.bin.ld",
+            path (apply_pattern (ld_d, fb ? nullptr : pat)),
+            false,
+            config::save_commented));
+
+        const path& ld (cast<path> (p.first));
+        ld_info ldi (guess_ld (ld, fb ? dir_path (*pat) : dir_path ()));
+
+        // If this is a new value (e.g., we are configuring), then print the
+        // report at verbosity level 2 and up (-v).
+        //
+        if (verb >= (p.second ? 2 : 3))
+        {
+          text << "bin.ld " << project (rs) << '@' << rs << '\n'
+               << "  ld         " << ldi.path << '\n'
+               << "  id         " << ldi.id << '\n'
+               << "  signature  " << ldi.signature << '\n'
+               << "  checksum   " << ldi.checksum;
+        }
+
+        rs.assign<process_path> ("bin.ld.path")      = move (ldi.path);
+        rs.assign<string>       ("bin.ld.id")        = move (ldi.id);
+        rs.assign<string>       ("bin.ld.signature") = move (ldi.signature);
+        rs.assign<string>       ("bin.ld.checksum")  = move (ldi.checksum);
+      }
+
+      return true;
+    }
+
+    bool
+    ld_init (scope& rs,
+             scope& bs,
+             const location& loc,
+             unique_ptr<module_base>&,
+             bool,
+             bool,
+             const variable_map& hints)
+    {
+      tracer trace ("bin::ld_init");
+      l5 ([&]{trace << "for " << bs;});
+
+      // Make sure the bin core and ld.config are loaded.
+      //
+      if (!cast_false<bool> (bs["bin.loaded"]))
+        load_module (rs, bs, "bin", loc, false, hints);
+
+      if (!cast_false<bool> (bs["bin.ld.config.loaded"]))
+        load_module (rs, bs, "bin.ld.config", loc, false, hints);
+
+      const string& lid (cast<string> (rs["bin.ld.id"]));
+
+      // Register the pdb{} target if using the VC toolchain.
+      //
+      using namespace install;
+
+      if (lid == "msvc")
+      {
+        const target_type& pdb (bs.derive_target_type<file> ("pdb").first);
+        install_path (bs, pdb, dir_path ("bin")); // Goes to install.bin
+        install_mode (bs, pdb, "644");            // But not executable.
+      }
+
+      return true;
+    }
+
+    bool
+    rc_config_init (scope& rs,
+                    scope& bs,
+                    const location& loc,
+                    unique_ptr<module_base>&,
+                    bool first,
+                    bool,
+                    const variable_map& hints)
+    {
+      tracer trace ("bin::rc_config_init");
+      l5 ([&]{trace << "for " << bs;});
+
+      // Make sure bin.config is loaded.
+      //
+      if (!cast_false<bool> (bs["bin.config.loaded"]))
+        load_module (rs, bs, "bin.config", loc, false, hints);
+
+      // Enter configuration variables.
+      //
+      if (first)
+      {
+        auto& v (rs.ctx.var_pool.rw (rs));
+
+        v.insert<process_path> ("bin.rc.path");
+        v.insert<path>         ("config.bin.rc", true);
+      }
+
+      // Configure.
+      //
+      if (first)
+      {
+        // config.bin.rc
+        //
+        // Use the target to decide on the default rc name.
+        //
+        const string& tsys (cast<string> (rs["bin.target.system"]));
+        const char* rc_d (tsys == "win32-msvc" ? "rc" : "windres");
+
+        // This can be either a pattern or a fallback search directory.
+        //
+        const string* pat (cast_null<string> (rs["bin.pattern"]));
+
+        bool fb (pat != nullptr &&
+                 path::traits_type::is_separator (pat->back ()));
+
+        auto p (
+          config::required (
+            rs,
+            "config.bin.rc",
+            path (apply_pattern (rc_d, fb ? nullptr : pat)),
+            false,
+            config::save_commented));
+
+        const path& rc (cast<path> (p.first));
+        rc_info rci (guess_rc (rc, fb ? dir_path (*pat) : dir_path ()));
+
+        // If this is a new value (e.g., we are configuring), then print the
+        // report at verbosity level 2 and up (-v).
+        //
+        if (verb >= (p.second ? 2 : 3))
+        {
+          text << "bin.rc " << project (rs) << '@' << rs << '\n'
+               << "  rc         " << rci.path << '\n'
+               << "  id         " << rci.id << '\n'
+               << "  signature  " << rci.signature << '\n'
+               << "  checksum   " << rci.checksum;
+        }
+
+        rs.assign<process_path> ("bin.rc.path")      = move (rci.path);
+        rs.assign<string>       ("bin.rc.id")        = move (rci.id);
+        rs.assign<string>       ("bin.rc.signature") = move (rci.signature);
+        rs.assign<string>       ("bin.rc.checksum")  = move (rci.checksum);
+      }
+
+      return true;
+    }
+
+    bool
+    rc_init (scope& rs,
+             scope& bs,
+             const location& loc,
+             unique_ptr<module_base>&,
+             bool,
+             bool,
+             const variable_map& hints)
+    {
+      tracer trace ("bin::rc_init");
+      l5 ([&]{trace << "for " << bs;});
+
+      // Make sure the bin core and rc.config are loaded.
+      //
+      if (!cast_false<bool> (bs["bin.loaded"]))
+        load_module (rs, bs, "bin", loc, false, hints);
+
+      if (!cast_false<bool> (bs["bin.rc.config.loaded"]))
+        load_module (rs, bs, "bin.rc.config", loc, false, 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.
+
+      {"bin.vars",      nullptr, vars_init},
+      {"bin.config",    nullptr, config_init},
+      {"bin",           nullptr, init},
+      {"bin.ar.config", nullptr, ar_config_init},
+      {"bin.ar",        nullptr, ar_init},
+      {"bin.ld.config", nullptr, ld_config_init},
+      {"bin.ld",        nullptr, ld_init},
+      {"bin.rc.config", nullptr, rc_config_init},
+      {"bin.rc",        nullptr, rc_init},
+      {nullptr,         nullptr, nullptr}
+    };
+
+    const module_functions*
+    build2_bin_load ()
+    {
+      return mod_functions;
+    }
+  }
+}
diff --git a/libbuild2/bin/init.hxx b/libbuild2/bin/init.hxx
new file mode 100644
index 0000000..41580df
--- /dev/null
+++ b/libbuild2/bin/init.hxx
@@ -0,0 +1,40 @@
+// file      : libbuild2/bin/init.hxx -*- C++ -*-
+// copyright : Copyright (c) 2014-2019 Code Synthesis Ltd
+// license   : MIT; see accompanying LICENSE file
+
+#ifndef LIBBUILD2_BIN_INIT_HXX
+#define LIBBUILD2_BIN_INIT_HXX
+
+#include <libbuild2/types.hxx>
+#include <libbuild2/utility.hxx>
+
+#include <libbuild2/module.hxx>
+
+#include <libbuild2/bin/export.hxx>
+
+namespace build2
+{
+  namespace bin
+  {
+    // Module `bin` does not require bootstrapping.
+    //
+    // Submodules:
+    //
+    // `bin.vars`      -- registers some variables.
+    // `bin.config`    -- loads bin.vars and sets some variables.
+    // `bin.ar.config` -- loads bin.config and registers/sets more variables.
+    // `bin.ar`        -- loads bin and bin.ar.config.
+    // `bin.ld.config` -- loads bin.config and registers/sets more variables.
+    // `bin.ld`        -- loads bin and bin.ld.config and registers more
+    //                    target types for msvc.
+    // `bin.rc.config` -- loads bin.config and registers/sets more variables.
+    // `bin.rc`        -- loads bin and bin.rc.config.
+    // `bin`           -- loads bin.config and registers target types and
+    //                    rules.
+    //
+    extern "C" LIBBUILD2_BIN_SYMEXPORT const module_functions*
+    build2_bin_load ();
+  }
+}
+
+#endif // LIBBUILD2_BIN_INIT_HXX
diff --git a/libbuild2/bin/rule.cxx b/libbuild2/bin/rule.cxx
new file mode 100644
index 0000000..8c1174a
--- /dev/null
+++ b/libbuild2/bin/rule.cxx
@@ -0,0 +1,89 @@
+// file      : build2/bin/rule.cxx -*- C++ -*-
+// copyright : Copyright (c) 2014-2019 Code Synthesis Ltd
+// license   : MIT; see accompanying LICENSE file
+
+#include <libbuild2/bin/rule.hxx>
+
+#include <libbuild2/scope.hxx>
+#include <libbuild2/target.hxx>
+#include <libbuild2/algorithm.hxx>
+#include <libbuild2/diagnostics.hxx>
+
+#include <libbuild2/bin/target.hxx>
+
+using namespace std;
+
+namespace build2
+{
+  namespace bin
+  {
+    // fail_rule
+    //
+    bool fail_rule::
+    match (action a, target& t, const string&) const
+    {
+      const char* n (t.dynamic_type ().name); // Ignore derived type.
+
+      fail << diag_doing (a, t) << " target group" <<
+        info << "explicitly select " << n << "e{}, " << n << "a{}, or "
+           << n << "s{} member" << endf;
+    }
+
+    recipe fail_rule::
+    apply (action, target&) const {return empty_recipe;}
+
+    // lib_rule
+    //
+    // The whole logic is pretty much as if we had our two group members as
+    // our prerequisites.
+    //
+    lib_rule::members lib_rule::
+    build_members (const scope& rs)
+    {
+      const string& type (cast<string> (rs["bin.lib"]));
+
+      bool a (type == "static" || type == "both");
+      bool s (type == "shared" || type == "both");
+
+      if (!a && !s)
+        fail << "unknown library type: " << type <<
+          info << "'static', 'shared', or 'both' expected";
+
+      return members {a, s};
+    }
+
+    bool lib_rule::
+    match (action, target& xt, const string&) const
+    {
+      lib& t (xt.as<lib> ());
+
+      members bm (build_members (t.root_scope ()));
+      t.a = bm.a ? &search<liba> (t, t.dir, t.out, t.name) : nullptr;
+      t.s = bm.s ? &search<libs> (t, t.dir, t.out, t.name) : nullptr;
+
+      return true;
+    }
+
+    recipe lib_rule::
+    apply (action a, target& xt) const
+    {
+      lib& t (xt.as<lib> ());
+
+      //@@ outer: also prerequisites (if outer) or not?
+
+      const target* m[] = {t.a, t.s};
+      match_members (a, t, m);
+
+      return &perform;
+    }
+
+    target_state lib_rule::
+    perform (action a, const target& xt)
+    {
+      const lib& t (xt.as<lib> ());
+
+      const target* m[] = {t.a, t.s};
+      return execute_members (a, t, m);
+    }
+  }
+}
diff --git a/libbuild2/bin/rule.hxx b/libbuild2/bin/rule.hxx
new file mode 100644
index 0000000..cfd096d
--- /dev/null
+++ b/libbuild2/bin/rule.hxx
@@ -0,0 +1,65 @@
+// file      : libbuild2/bin/rule.hxx -*- C++ -*-
+// copyright : Copyright (c) 2014-2019 Code Synthesis Ltd
+// license   : MIT; see accompanying LICENSE file
+
+#ifndef LIBBUILD2_BIN_RULE_HXX
+#define LIBBUILD2_BIN_RULE_HXX
+
+#include <libbuild2/types.hxx>
+#include <libbuild2/utility.hxx>
+
+#include <libbuild2/rule.hxx>
+
+#include <libbuild2/bin/export.hxx>
+
+namespace build2
+{
+  namespace bin
+  {
+    // "Fail rule" for obj{}, [h]bmi{}, and libu{} that issues diagnostics if
+    // someone tries to build any of these groups directly.
+    //
+    class fail_rule: public rule
+    {
+    public:
+      fail_rule () {}
+
+      virtual bool
+      match (action, target&, const string&) const override;
+
+      virtual recipe
+      apply (action, target&) const override;
+    };
+
+    // Pass-through to group members rule, similar to alias.
+    //
+    class LIBBUILD2_BIN_SYMEXPORT lib_rule: public rule
+    {
+    public:
+      lib_rule () {}
+
+      virtual bool
+      match (action, target&, const string&) const override;
+
+      virtual recipe
+      apply (action, target&) const override;
+
+      static target_state
+      perform (action, const target&);
+
+      // Return library types to build according to the bin.lib value (set
+      // on project's root scope by init()).
+      //
+      struct members
+      {
+        bool a; // static
+        bool s; // shared
+      };
+
+      static members
+      build_members (const scope&);
+    };
+  }
+}
+
+#endif // LIBBUILD2_BIN_RULE_HXX
diff --git a/libbuild2/bin/target.cxx b/libbuild2/bin/target.cxx
new file mode 100644
index 0000000..dd8a947
--- /dev/null
+++ b/libbuild2/bin/target.cxx
@@ -0,0 +1,474 @@
+// file      : libbuild2/bin/target.cxx -*- C++ -*-
+// copyright : Copyright (c) 2014-2019 Code Synthesis Ltd
+// license   : MIT; see accompanying LICENSE file
+
+#include <libbuild2/bin/target.hxx>
+
+#include <libbuild2/context.hxx>
+
+using namespace std;
+
+namespace build2
+{
+  namespace bin
+  {
+    const target_type objx::static_type
+    {
+      "objx",
+      &file::static_type,
+      nullptr,
+      nullptr,
+      nullptr,
+      nullptr,
+      nullptr,
+      &target_search,
+      false
+    };
+
+    const target_type bmix::static_type
+    {
+      "bmix",
+      &file::static_type,
+      nullptr,
+      nullptr,
+      nullptr,
+      nullptr,
+      nullptr,
+      &target_search,
+      false
+    };
+
+    const target_type hbmix::static_type
+    {
+      "hbmix",
+      &bmix::static_type,
+      nullptr,
+      nullptr,
+      nullptr,
+      nullptr,
+      nullptr,
+      &target_search,
+      false
+    };
+
+    const target_type libx::static_type
+    {
+      "libx",
+      &mtime_target::static_type,
+      nullptr,
+      nullptr,
+      nullptr,
+      nullptr,
+      nullptr,
+      &target_search,
+      false
+    };
+
+    const target_type libux::static_type
+    {
+      "libux",
+      &file::static_type,
+      nullptr,
+      nullptr,
+      nullptr,
+      nullptr,
+      nullptr,
+      &target_search,
+      false
+    };
+
+    // Note that we link groups during the load phase since this is often
+    // relied upon when setting target-specific variables (e.g., we may set a
+    // common value for lib{} and then append liba/libs-specific values to
+    // it). While sure inelegant, this is MT-safe since during load we are
+    // running serial. For the members it is also safe to set the group during
+    // creation.
+
+    // obj*{} and [h]bmi*{} member factory.
+    //
+    template <typename M, typename G>
+    static target*
+    m_factory (context& ctx,
+               const target_type&, dir_path dir, dir_path out, string n)
+    {
+      const G* g (ctx.targets.find<G> (dir, out, n));
+
+      M* m (new M (ctx, move (dir), move (out), move (n)));
+      m->group = g;
+
+      return m;
+    }
+
+    const target_type obje::static_type
+    {
+      "obje",
+      &objx::static_type,
+      &m_factory<obje, obj>,
+      nullptr, /* fixed_extension */
+      &target_extension_var<nullptr>,
+      &target_pattern_var<nullptr>,
+      nullptr,
+      &target_search, // Note: not _file(); don't look for an existing file.
+      false
+    };
+
+    const target_type bmie::static_type
+    {
+      "bmie",
+      &bmix::static_type,
+      &m_factory<bmie, bmi>,
+      nullptr, /* fixed_extension */
+      &target_extension_var<nullptr>,
+      &target_pattern_var<nullptr>,
+      nullptr,
+      &target_search, // Note: not _file(); don't look for an existing file.
+      false
+    };
+
+    const target_type hbmie::static_type
+    {
+      "hbmie",
+      &hbmix::static_type,
+      &m_factory<hbmie, hbmi>,
+      nullptr, /* fixed_extension */
+      &target_extension_var<nullptr>,
+      &target_pattern_var<nullptr>,
+      nullptr,
+      &target_search, // Note: not _file(); don't look for an existing file.
+      false
+    };
+
+    const target_type obja::static_type
+    {
+      "obja",
+      &objx::static_type,
+      &m_factory<obja, obj>,
+      nullptr, /* fixed_extension */
+      &target_extension_var<nullptr>,
+      &target_pattern_var<nullptr>,
+      nullptr,
+      &target_search, // Note: not _file(); don't look for an existing file.
+      false
+    };
+
+    const target_type bmia::static_type
+    {
+      "bmia",
+      &bmix::static_type,
+      &m_factory<bmia, bmi>,
+      nullptr, /* fixed_extension */
+      &target_extension_var<nullptr>,
+      &target_pattern_var<nullptr>,
+      nullptr,
+      &target_search, // Note: not _file(); don't look for an existing file.
+      false
+    };
+
+    const target_type hbmia::static_type
+    {
+      "hbmia",
+      &hbmix::static_type,
+      &m_factory<hbmia, hbmi>,
+      nullptr, /* fixed_extension */
+      &target_extension_var<nullptr>,
+      &target_pattern_var<nullptr>,
+      nullptr,
+      &target_search, // Note: not _file(); don't look for an existing file.
+      false
+    };
+
+    const target_type objs::static_type
+    {
+      "objs",
+      &objx::static_type,
+      &m_factory<objs, obj>,
+      nullptr, /* fixed_extension */
+      &target_extension_var<nullptr>,
+      &target_pattern_var<nullptr>,
+      nullptr,
+      &target_search, // Note: not _file(); don't look for an existing file.
+      false
+    };
+
+    const target_type bmis::static_type
+    {
+      "bmis",
+      &bmix::static_type,
+      &m_factory<bmis, bmi>,
+      nullptr, /* fixed_extension */
+      &target_extension_var<nullptr>,
+      &target_pattern_var<nullptr>,
+      nullptr,
+      &target_search, // Note: not _file(); don't look for an existing file.
+      false
+    };
+
+    const target_type hbmis::static_type
+    {
+      "hbmis",
+      &hbmix::static_type,
+      &m_factory<hbmis, hbmi>,
+      nullptr, /* fixed_extension */
+      &target_extension_var<nullptr>,
+      &target_pattern_var<nullptr>,
+      nullptr,
+      &target_search, // Note: not _file(); don't look for an existing file.
+      false
+    };
+
+    const target_type libue::static_type
+    {
+      "libue",
+      &libux::static_type,
+      &target_factory<libue>,
+      nullptr, /* fixed_extension */
+      &target_extension_var<nullptr>,
+      &target_pattern_var<nullptr>,
+      nullptr,
+      &target_search, // Note: not _file(); don't look for an existing file.
+      false
+    };
+
+    const target_type libua::static_type
+    {
+      "libua",
+      &libux::static_type,
+      &m_factory<libua, libul>,
+      nullptr, /* fixed_extension */
+      &target_extension_var<nullptr>,
+      &target_pattern_var<nullptr>,
+      nullptr,
+      &target_search, // Note: not _file(); don't look for an existing file.
+      false
+    };
+
+    const target_type libus::static_type
+    {
+      "libus",
+      &libux::static_type,
+      &m_factory<libus, libul>,
+      nullptr, /* fixed_extension */
+      &target_extension_var<nullptr>,
+      &target_pattern_var<nullptr>,
+      nullptr,
+      &target_search, // Note: not _file(); don't look for an existing file.
+      false
+    };
+
+    // obj{}, [h]bmi{}, and libu{} group factory.
+    //
+    template <typename G, typename E, typename A, typename S>
+    static target*
+    g_factory (context& ctx,
+               const target_type&, dir_path dir, dir_path out, string n)
+    {
+      // Casts are MT-aware (during serial load).
+      //
+      E* e (ctx.phase == run_phase::load
+            ? const_cast<E*> (ctx.targets.find<E> (dir, out, n))
+            : nullptr);
+      A* a (ctx.phase == run_phase::load
+            ? const_cast<A*> (ctx.targets.find<A> (dir, out, n))
+            : nullptr);
+      S* s (ctx.phase == run_phase::load
+            ? const_cast<S*> (ctx.targets.find<S> (dir, out, n))
+            : nullptr);
+
+      G* g (new G (ctx, move (dir), move (out), move (n)));
+
+      if (e != nullptr) e->group = g;
+      if (a != nullptr) a->group = g;
+      if (s != nullptr) s->group = g;
+
+      return g;
+    }
+
+    const target_type obj::static_type
+    {
+      "obj",
+      &target::static_type,
+      &g_factory<obj, obje, obja, objs>,
+      nullptr,
+      nullptr,
+      nullptr,
+      nullptr,
+      &target_search,
+      false
+    };
+
+    const target_type bmi::static_type
+    {
+      "bmi",
+      &target::static_type,
+      &g_factory<bmi, bmie, bmia, bmis>,
+      nullptr,
+      nullptr,
+      nullptr,
+      nullptr,
+      &target_search,
+      false
+    };
+
+    const target_type hbmi::static_type
+    {
+      "hbmi",
+      &target::static_type,
+      &g_factory<hbmi, hbmie, hbmia, hbmis>,
+      nullptr,
+      nullptr,
+      nullptr,
+      nullptr,
+      &target_search,
+      false
+    };
+
+    // The same as g_factory() but without E.
+    //
+    static target*
+    libul_factory (context& ctx,
+                   const target_type&, dir_path dir, dir_path out, string n)
+    {
+      libua* a (ctx.phase == run_phase::load
+                ? const_cast<libua*> (ctx.targets.find<libua> (dir, out, n))
+                : nullptr);
+      libus* s (ctx.phase == run_phase::load
+                ? const_cast<libus*> (ctx.targets.find<libus> (dir, out, n))
+                : nullptr);
+
+      libul* g (new libul (ctx, move (dir), move (out), move (n)));
+
+      if (a != nullptr) a->group = g;
+      if (s != nullptr) s->group = g;
+
+      return g;
+    }
+
+    const target_type libul::static_type
+    {
+      "libul",
+      &libx::static_type,
+      &libul_factory,
+      nullptr,
+      nullptr,
+      nullptr,
+      nullptr,
+      &target_search,
+      false
+    };
+
+    // What extensions should we use? At the outset, this is platform-
+    // dependent. And if we consider cross-compilation, is it build or
+    // host-dependent? Feels like it should be host-dependent so that
+    // we can copy things between cross and native environments. So
+    // these will have to be determined based on what we are building.
+    // As if this is not complicated enough, the bin module doesn't
+    // know anything about building. So perhaps the extension should
+    // come from a variable that is set not by bin but by the module
+    // whose rule matched the target (e.g., cxx::link).
+    //
+    const target_type liba::static_type
+    {
+      "liba",
+      &file::static_type,
+      &m_factory<liba, lib>,
+      nullptr, /* fixed_extension */
+      &target_extension_var<nullptr>,
+      &target_pattern_var<nullptr>,
+      nullptr,
+      &file_search,
+      false
+    };
+
+    const target_type libs::static_type
+    {
+      "libs",
+      &file::static_type,
+      &m_factory<libs, lib>,
+      nullptr, /* fixed_extension */
+      &target_extension_var<nullptr>,
+      &target_pattern_var<nullptr>,
+      nullptr,
+      &file_search,
+      false
+    };
+
+    // lib
+    //
+    group_view lib::
+    group_members (action) const
+    {
+      static_assert (sizeof (lib_members) == sizeof (const target*) * 2,
+                     "member layout incompatible with array");
+
+      return a != nullptr || s != nullptr
+        ? group_view {reinterpret_cast<const target* const*> (&a), 2}
+        : group_view {nullptr, 0};
+    }
+
+    static target*
+    lib_factory (context& ctx,
+                 const target_type&, dir_path dir, dir_path out, string n)
+    {
+      // Casts are MT-aware (during serial load).
+      //
+      liba* a (ctx.phase == run_phase::load
+               ? const_cast<liba*> (ctx.targets.find<liba> (dir, out, n))
+               : nullptr);
+      libs* s (ctx.phase == run_phase::load
+               ? const_cast<libs*> (ctx.targets.find<libs> (dir, out, n))
+               : nullptr);
+
+      lib* l (new lib (ctx, move (dir), move (out), move (n)));
+
+      if (a != nullptr) a->group = l;
+      if (s != nullptr) s->group = l;
+
+      return l;
+    }
+
+    const target_type lib::static_type
+    {
+      "lib",
+      &libx::static_type,
+      &lib_factory,
+      nullptr,
+      nullptr,
+      nullptr,
+      nullptr,
+      &target_search,
+      false // Note: not see-through ("alternatives" group).
+    };
+
+    // libi
+    //
+    const target_type libi::static_type
+    {
+      "libi",
+      &file::static_type,
+      &target_factory<libi>,
+      nullptr, /* fixed_extension */
+      &target_extension_var<nullptr>,
+      &target_pattern_var<nullptr>,
+      nullptr,
+      &file_search,
+      false
+    };
+
+    // def
+    //
+    extern const char def_ext[] = "def"; // VC14 rejects constexpr.
+
+    const target_type def::static_type
+    {
+      "def",
+      &file::static_type,
+      &target_factory<def>,
+      &target_extension_fix<def_ext>,
+      nullptr,                          /* default_extension */
+      &target_pattern_fix<def_ext>,
+      nullptr,
+      &file_search,
+      false
+    };
+  }
+}
diff --git a/libbuild2/bin/target.hxx b/libbuild2/bin/target.hxx
new file mode 100644
index 0000000..3b1708a
--- /dev/null
+++ b/libbuild2/bin/target.hxx
@@ -0,0 +1,363 @@
+// file      : libbuild2/bin/target.hxx -*- C++ -*-
+// copyright : Copyright (c) 2014-2019 Code Synthesis Ltd
+// license   : MIT; see accompanying LICENSE file
+
+#ifndef LIBBUILD2_BIN_TARGET_HXX
+#define LIBBUILD2_BIN_TARGET_HXX
+
+#include <libbuild2/types.hxx>
+#include <libbuild2/utility.hxx>
+
+#include <libbuild2/target.hxx>
+
+#include <libbuild2/bin/export.hxx>
+
+namespace build2
+{
+  namespace bin
+  {
+    // The obj{} target group.
+    //
+    // Common base of all objX{} object files.
+    //
+    class LIBBUILD2_BIN_SYMEXPORT objx: public file
+    {
+    public:
+      using file::file;
+
+    public:
+      static const target_type static_type;
+    };
+
+    class LIBBUILD2_BIN_SYMEXPORT obje: public objx
+    {
+    public:
+      using objx::objx;
+
+    public:
+      static const target_type static_type;
+      virtual const target_type& dynamic_type () const {return static_type;}
+    };
+
+    class LIBBUILD2_BIN_SYMEXPORT obja: public objx
+    {
+    public:
+      using objx::objx;
+
+    public:
+      static const target_type static_type;
+      virtual const target_type& dynamic_type () const {return static_type;}
+    };
+
+    class LIBBUILD2_BIN_SYMEXPORT objs: public objx
+    {
+    public:
+      using objx::objx;
+
+    public:
+      static const target_type static_type;
+      virtual const target_type& dynamic_type () const {return static_type;}
+    };
+
+    class LIBBUILD2_BIN_SYMEXPORT obj: public target
+    {
+    public:
+      using target::target;
+
+    public:
+      static const target_type static_type;
+      virtual const target_type& dynamic_type () const {return static_type;}
+    };
+
+    // Binary module interface (BMI).
+    //
+    // While currently there are only C++ modules, if things pan out, chances
+    // are we will have C (or Obj-C) modules. And in that case it is plausible
+    // we will also have some binutils to examine BMIs, similar to objdump,
+    // etc. So that's why this target type is in bin and not cxx.
+    //
+    // bmi*{} is similar to obj*{} though the semantics is a bit different:
+    // the idea is that we should try hard to re-use a single bmiX{} file for
+    // an entire "build" but if that's not possible (because the compilation
+    // options are too different), then compile a private version for
+    // ourselves (the definition of "too different" is, of course, compiler-
+    // specific).
+    //
+    // When we compile a module interface unit, we end up with bmi*{} and
+    // obj*{}. How that obj*{} is produced is compiler-dependent. While it
+    // makes sense to decouple the production of the two in order to increase
+    // parallelism, doing so will further complicate the already hairy
+    // organization. So, at least for now, we produce the two at the same time
+    // and make obj*{} an ad hoc member of bmi*{}.
+    //
+    // There are also header units for which we define a parallel hbmi*{}
+    // hierarchy. Note that hbmix{} is-a bmix{} (we think of header BMIs as a
+    // more specialized kind of BMI) so where you need to distinguish between
+    // header and module BMIs, you should check for headers first. Note also
+    // that in case of a header unit there may be no obj*{}.
+    //
+    // Common base of all bmiX{} interface files.
+    //
+    class LIBBUILD2_BIN_SYMEXPORT bmix: public file
+    {
+    public:
+      using file::file;
+
+    public:
+      static const target_type static_type;
+    };
+
+    // Common base of all hbmiX{} interface files.
+    //
+    class LIBBUILD2_BIN_SYMEXPORT hbmix: public bmix
+    {
+    public:
+      using bmix::bmix;
+
+    public:
+      static const target_type static_type;
+    };
+
+    class LIBBUILD2_BIN_SYMEXPORT bmie: public bmix
+    {
+    public:
+      using bmix::bmix;
+
+    public:
+      static const target_type static_type;
+      virtual const target_type& dynamic_type () const {return static_type;}
+    };
+
+    class LIBBUILD2_BIN_SYMEXPORT hbmie: public hbmix
+    {
+    public:
+      using hbmix::hbmix;
+
+    public:
+      static const target_type static_type;
+      virtual const target_type& dynamic_type () const {return static_type;}
+    };
+
+    class LIBBUILD2_BIN_SYMEXPORT bmia: public bmix
+    {
+    public:
+      using bmix::bmix;
+
+    public:
+      static const target_type static_type;
+      virtual const target_type& dynamic_type () const {return static_type;}
+    };
+
+    class LIBBUILD2_BIN_SYMEXPORT hbmia: public hbmix
+    {
+    public:
+      using hbmix::hbmix;
+
+    public:
+      static const target_type static_type;
+      virtual const target_type& dynamic_type () const {return static_type;}
+    };
+
+    class LIBBUILD2_BIN_SYMEXPORT bmis: public bmix
+    {
+    public:
+      using bmix::bmix;
+
+    public:
+      static const target_type static_type;
+      virtual const target_type& dynamic_type () const {return static_type;}
+    };
+
+    class LIBBUILD2_BIN_SYMEXPORT hbmis: public hbmix
+    {
+    public:
+      using hbmix::hbmix;
+
+    public:
+      static const target_type static_type;
+      virtual const target_type& dynamic_type () const {return static_type;}
+    };
+
+    class LIBBUILD2_BIN_SYMEXPORT bmi: public target
+    {
+    public:
+      using target::target;
+
+    public:
+      static const target_type static_type;
+      virtual const target_type& dynamic_type () const {return static_type;}
+    };
+
+    class LIBBUILD2_BIN_SYMEXPORT hbmi: public target
+    {
+    public:
+      using target::target;
+
+    public:
+      static const target_type static_type;
+      virtual const target_type& dynamic_type () const {return static_type;}
+    };
+
+
+    // Common base for lib{} and libul{} groups.
+    //
+    // We use mtime_target as a base for the "trust me it exists" functionality
+    // which we use, for example, to have installed lib{} prerequisites that
+    // are matched by the fallback file rule.
+    //
+    class LIBBUILD2_BIN_SYMEXPORT libx: public mtime_target
+    {
+    public:
+      using mtime_target::mtime_target;
+
+    public:
+      static const target_type static_type;
+    };
+
+    // The libue{} target, libul{} group and libua{} and libus{} members
+    // (utility library).
+    //
+    // Utility libraries are static libraries that differ based on the kind of
+    // object files they contains. Note that the libul{} group is more like
+    // obj{} rather than lib{} in that one does not build the group directly
+    // rather picking a suitable member.
+    //
+    // libul{} is a "library utility library" in that the choice of members is
+    // libua{} or libus{}, even when linking an executable (normally a unit
+    // test).
+    //
+    // Note that there is no "general utility library" with all three types of
+    // members (that would cause member uplink ambiguity). If you need to
+    // build both a library from libua{}/libus{} and an executable from
+    // libue{} then you will need to arrange this explicitly, for example:
+    //
+    // exe{foo}: libue{foo}
+    // lib{foo}: libul{foo}
+    //
+    // {libue libul}{foo}: cxx{*}
+    //
+    // Common base of all libuX{} static libraries.
+    //
+    class LIBBUILD2_BIN_SYMEXPORT libux: public file
+    {
+    public:
+      using file::file;
+
+    public:
+      static const target_type static_type;
+    };
+
+    class LIBBUILD2_BIN_SYMEXPORT libue: public libux
+    {
+    public:
+      using libux::libux;
+
+    public:
+      static const target_type static_type;
+      virtual const target_type& dynamic_type () const {return static_type;}
+    };
+
+    class LIBBUILD2_BIN_SYMEXPORT libua: public libux
+    {
+    public:
+      using libux::libux;
+
+    public:
+      static const target_type static_type;
+      virtual const target_type& dynamic_type () const {return static_type;}
+    };
+
+    class LIBBUILD2_BIN_SYMEXPORT libus: public libux
+    {
+    public:
+      using libux::libux;
+
+    public:
+      static const target_type static_type;
+      virtual const target_type& dynamic_type () const {return static_type;}
+    };
+
+    class LIBBUILD2_BIN_SYMEXPORT libul: public libx
+    {
+    public:
+      using libx::libx;
+
+    public:
+      static const target_type static_type;
+      virtual const target_type& dynamic_type () const {return static_type;}
+    };
+
+    // The lib{} target group.
+    //
+    class LIBBUILD2_BIN_SYMEXPORT liba: public file
+    {
+    public:
+      using file::file;
+
+    public:
+      static const target_type static_type;
+      virtual const target_type& dynamic_type () const {return static_type;}
+    };
+
+    class LIBBUILD2_BIN_SYMEXPORT libs: public file
+    {
+    public:
+      using file::file;
+
+    public:
+      static const target_type static_type;
+
+      virtual const target_type&
+      dynamic_type () const override {return static_type;}
+    };
+
+    // Standard layout type compatible with group_view's const target*[2].
+    //
+    struct lib_members
+    {
+      const liba* a = nullptr;
+      const libs* s = nullptr;
+    };
+
+    class LIBBUILD2_BIN_SYMEXPORT lib: public libx, public lib_members
+    {
+    public:
+      using libx::libx;
+
+      virtual group_view
+      group_members (action) const override;
+
+    public:
+      static const target_type static_type;
+
+      virtual const target_type&
+      dynamic_type () const override {return static_type;}
+    };
+
+    // Windows import library.
+    //
+    class LIBBUILD2_BIN_SYMEXPORT libi: public file
+    {
+    public:
+      using file::file;
+
+    public:
+      static const target_type static_type;
+      virtual const target_type& dynamic_type () const {return static_type;}
+    };
+
+    // Windows module definition (.def).
+    //
+    class LIBBUILD2_BIN_SYMEXPORT def: public file
+    {
+    public:
+      using file::file;
+
+    public:
+      static const target_type static_type;
+      virtual const target_type& dynamic_type () const {return static_type;}
+    };
+  }
+}
+
+#endif // LIBBUILD2_BIN_TARGET_HXX