Add bin.ld sub-module

4 files changed, 235 insertions, 20 deletions

diff --git a/build2/bin/guess b/build2/bin/guess
index a80539e..d6ff76d 100644
--- a/build2/bin/guess
+++ b/build2/bin/guess
@@ -28,7 +28,7 @@ namespace build2
     // a toolchain-specific manner (usually the output of --version/-V) and
     // is not bulletproof.
     //
-    struct bin_info
+    struct ar_info
     {
       string ar_id;
       string ar_signature;
@@ -43,8 +43,38 @@ namespace build2
     // attemplated and the returned ranlib_* members will be left empty as
     // well.
     //
-    bin_info
-    guess (const path& ar, const path& ranlib);
+    ar_info
+    guess_ar (const path& ar, const path& ranlib);
+
+    // ld information.
+    //
+    // Currently recognized ld 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
+    {
+      string ld_id;
+      string ld_signature;
+      string ld_checksum;
+    };
+
+    ld_info
+    guess_ld (const path& ld);
   }
 }
 
diff --git a/build2/bin/guess.cxx b/build2/bin/guess.cxx
index d036f81..ea4ac49 100644
--- a/build2/bin/guess.cxx
+++ b/build2/bin/guess.cxx
@@ -22,10 +22,10 @@ namespace build2
       empty () const {return id.empty ();}
     };
 
-    bin_info
-    guess (const path& ar, const path& rl)
+    ar_info
+    guess_ar (const path& ar, const path& rl)
     {
-      tracer trace ("bin::guess");
+      tracer trace ("bin::guess_ar");
 
       guess_result arr, rlr;
 
@@ -166,9 +166,121 @@ namespace build2
           fail << "unable to guess " << rl << " signature";
       }
 
-      return bin_info {
+      return ar_info {
         move (arr.id), move (arr.signature), move (arr.checksum),
         move (rlr.id), move (rlr.signature), move (rlr.checksum)};
     }
+
+    ld_info
+    guess_ld (const path& ld)
+    {
+      tracer trace ("bin::guess_ld");
+
+      guess_result r;
+
+      // 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 exist 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.
+      //
+      {
+        auto f = [] (string& l) -> guess_result
+        {
+          // Microsoft link.exe output starts with "Microsoft (R) ".
+          //
+          if (l.compare (0, 14, "Microsoft (R) ") == 0)
+            return guess_result {"msvc", move (l), ""};
+
+          // Binutils ld.bfd --version output has a line that starts with
+          // "GNU ld " while ld.gold -- "GNU gold".
+          //
+          if (l.compare (0, 7, "GNU ld ") == 0)
+            return guess_result {"gnu", move (l), ""};
+
+          if (l.compare (0, 9, "GNU gold ") == 0)
+            return guess_result {"gold", move (l), ""};
+
+          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> (ld, "--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) -> 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), ""};
+
+          // 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), ""};
+
+          return guess_result ();
+        };
+
+        sha256 cs;
+        r = run<guess_result> (ld, "-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) -> 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), ""};
+
+          return guess_result ();
+        };
+
+        // Suppress all the errors because we may be trying an unsupported
+        // option.
+        //
+        sha256 cs;
+        r = run<guess_result> (ld, "-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 (r.id), move (r.signature), move (r.checksum)};
+    }
   }
 }
diff --git a/build2/bin/module b/build2/bin/module
index e74cbe2..fa592cf 100644
--- a/build2/bin/module
+++ b/build2/bin/module
@@ -22,6 +22,15 @@ namespace build2
           bool,
           bool,
           const variable_map&);
+
+    bool
+    ld_init (scope&,
+             scope&,
+             const location&,
+             unique_ptr<module_base>&,
+             bool,
+             bool,
+             const variable_map&);
   }
 }
 
diff --git a/build2/bin/module.cxx b/build2/bin/module.cxx
index 9ce069c..f5e44db 100644
--- a/build2/bin/module.cxx
+++ b/build2/bin/module.cxx
@@ -305,7 +305,7 @@ namespace build2
         const path& ar (cast<path> (p.first));
         const path& ranlib (v ? cast<path> (v) : path ());
 
-        bin_info bi (guess (ar, ranlib));
+        ar_info ai (guess_ar (ar, ranlib));
 
         // If this is a new value (e.g., we are configuring), then print the
         // report at verbosity level 2 and up (-v).
@@ -316,30 +316,30 @@ namespace build2
 
           text << "bin.ar\n"
                << "  exe        " << ar << '\n'
-               << "  id         " << bi.ar_id << '\n'
-               << "  signature  " << bi.ar_signature << '\n'
-               << "  checksum   " << bi.ar_checksum;
+               << "  id         " << ai.ar_id << '\n'
+               << "  signature  " << ai.ar_signature << '\n'
+               << "  checksum   " << ai.ar_checksum;
 
           if (!ranlib.empty ())
           {
             text << "bin.ranlib\n"
                  << "  exe        " << ranlib << '\n'
-                 << "  id         " << bi.ranlib_id << '\n'
-                 << "  signature  " << bi.ranlib_signature << '\n'
-                 << "  checksum   " << bi.ranlib_checksum;
+                 << "  id         " << ai.ranlib_id << '\n'
+                 << "  signature  " << ai.ranlib_signature << '\n'
+                 << "  checksum   " << ai.ranlib_checksum;
           }
         }
 
-        r.assign<string> ("bin.ar.id") = move (bi.ar_id);
-        r.assign<string> ("bin.ar.signature") = move (bi.ar_signature);
-        r.assign<string> ("bin.ar.checksum") = move (bi.ar_checksum);
+        r.assign<string> ("bin.ar.id") = move (ai.ar_id);
+        r.assign<string> ("bin.ar.signature") = move (ai.ar_signature);
+        r.assign<string> ("bin.ar.checksum") = move (ai.ar_checksum);
 
         if (!ranlib.empty ())
         {
-          r.assign<string> ("bin.ranlib.id") = move (bi.ranlib_id);
+          r.assign<string> ("bin.ranlib.id") = move (ai.ranlib_id);
           r.assign<string> ("bin.ranlib.signature") =
-            move (bi.ranlib_signature);
-          r.assign<string> ("bin.ranlib.checksum") = move (bi.ranlib_checksum);
+            move (ai.ranlib_signature);
+          r.assign<string> ("bin.ranlib.checksum") = move (ai.ranlib_checksum);
         }
       }
 
@@ -421,5 +421,69 @@ namespace build2
 
       return true;
     }
+
+    bool
+    ld_init (scope& r,
+             scope& b,
+             const location& loc,
+             unique_ptr<module_base>&,
+             bool first,
+             bool,
+             const variable_map& config_hints)
+    {
+      tracer trace ("bin::ld_init");
+      l5 ([&]{trace << "for " << b.out_path ();});
+
+      // Make sure the bin core is loaded.
+      //
+      if (!cast_false<bool> (b["bin.loaded"]))
+        load_module ("bin", r, b, loc, false, config_hints);
+
+      // Enter module variables.
+      //
+      if (first)
+      {
+        auto& v (var_pool);
+
+        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> (r["bin.target.system"]));
+        const char* ld_d (tsys == "win32-msvc" ? "link" : "ld");
+
+        auto p (config::required (r,
+                                  "config.bin.ld",
+                                  path (apply (r["bin.pattern"], ld_d))));
+
+        const path& ld (cast<path> (p.first));
+        ld_info li (guess_ld (ld));
+
+        // 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\n"
+               << "  exe        " << ld << '\n'
+               << "  id         " << li.ld_id << '\n'
+               << "  signature  " << li.ld_signature << '\n'
+               << "  checksum   " << li.ld_checksum;
+        }
+
+        r.assign<string> ("bin.ld.id") = move (li.ld_id);
+        r.assign<string> ("bin.ld.signature") = move (li.ld_signature);
+        r.assign<string> ("bin.ld.checksum") = move (li.ld_checksum);
+      }
+
+      return true;
+    }
   }
 }