Implement support for importing installed libraries

1 files changed, 782 insertions, 0 deletions

diff --git a/build/cxx/compile.cxx b/build/cxx/compile.cxx
new file mode 100644
index 0000000..d0e6526
--- /dev/null
+++ b/build/cxx/compile.cxx
@@ -0,0 +1,782 @@
+// file      : build/cxx/compile.cxx -*- C++ -*-
+// copyright : Copyright (c) 2014-2015 Code Synthesis Ltd
+// license   : MIT; see accompanying LICENSE file
+
+#include <build/cxx/compile>
+
+#include <map>
+#include <string>
+#include <cstddef>  // size_t
+#include <cstdlib>  // exit()
+#include <utility>  // move()
+
+#include <butl/process>
+#include <butl/utility>  // reverse_iterate
+#include <butl/fdstream>
+#include <butl/path-map>
+
+#include <build/types>
+#include <build/scope>
+#include <build/variable>
+#include <build/algorithm>
+#include <build/diagnostics>
+#include <build/context>
+
+#include <build/bin/target>
+#include <build/cxx/target>
+
+#include <build/cxx/utility>
+#include <build/cxx/link>
+
+using namespace std;
+using namespace butl;
+
+namespace build
+{
+  namespace cxx
+  {
+    using namespace bin;
+
+    match_result compile::
+    match (action a, target& t, const string&) const
+    {
+      tracer trace ("cxx::compile::match");
+
+      // @@ TODO:
+      //
+      // - check prerequisites: single source file
+      // - check prerequisites: the rest are headers (other ignorable?)
+      // - if path already assigned, verify extension?
+      //
+
+      // See if we have a C++ source file. Iterate in reverse so that
+      // a source file specified for an obj*{} member overrides the one
+      // specified for the group. Also "see through" groups.
+      //
+      for (prerequisite_member p: reverse_group_prerequisite_members (a, t))
+      {
+        if (p.is_a<cxx> ())
+          return p;
+      }
+
+      level3 ([&]{trace << "no c++ source file for target " << t;});
+      return nullptr;
+    }
+
+    static void
+    inject_prerequisites (action, target&, cxx&, scope&);
+
+    recipe compile::
+    apply (action a, target& xt, const match_result& mr) const
+    {
+      path_target& t (static_cast<path_target&> (xt));
+
+      // Derive file name from target name.
+      //
+      if (t.path ().empty ())
+        t.derive_path ("o", nullptr, (t.is_a<objso> () ? "-so" : nullptr));
+
+      // Inject dependency on the output directory.
+      //
+      inject_parent_fsdir (a, t);
+
+      // Search and match all the existing prerequisites. The injection
+      // code (below) takes care of the ones it is adding.
+      //
+      // When cleaning, ignore prerequisites that are not in the same
+      // or a subdirectory of our strong amalgamation.
+      //
+      const dir_path* amlg (
+        a.operation () != clean_id
+        ? nullptr
+        : &t.strong_scope ().path ());
+
+      link::search_paths_cache lib_paths; // Extract lazily.
+
+      for (prerequisite_member p: group_prerequisite_members (a, t))
+      {
+        // A dependency on a library is there so that we can get its
+        // cxx.export.poptions. In particular, making sure it is
+        // executed before us will only restrict parallelism. But we
+        // do need to match it in order to get its prerequisite_targets
+        // populated; see append_lib_options() above.
+        //
+        if (p.is_a<lib> () || p.is_a<liba> () || p.is_a<libso> ())
+        {
+          if (a.operation () == update_id)
+          {
+            // Handle imported libraries.
+            //
+            if (p.proj () != nullptr)
+            {
+              // We know that for such libraries we don't need to do
+              // match() in order to get options (if any, they would
+              // be set by search_library()).
+              //
+              if (link::search_library (lib_paths, p.prerequisite) != nullptr)
+                continue;
+            }
+
+            target& pt (p.search ());
+
+            // @@ The fact that we match but never execute messes up
+            //    the dependents count. This is a workaround, not a
+            //    solution.
+            //
+            build::match (a, pt);
+          }
+
+          continue;
+        }
+
+        target& pt (p.search ());
+
+        if (a.operation () == clean_id && !pt.dir.sub (*amlg))
+          continue;
+
+        build::match (a, pt);
+        t.prerequisite_targets.push_back (&pt);
+      }
+
+      // Inject additional prerequisites. We only do it for update
+      // since chances are we will have to update some of our
+      // prerequisites in the process (auto-generated source code).
+      //
+      if (a.operation () == update_id)
+      {
+        // The cached prerequisite target should be the same as what
+        // is in t.prerequisite_targets since we used standard
+        // search() and match() above.
+        //
+        // @@ Ugly.
+        //
+        cxx& st (
+          dynamic_cast<cxx&> (
+            mr.target != nullptr ? *mr.target : *mr.prerequisite->target));
+        inject_prerequisites (a, t, st, mr.prerequisite->scope);
+      }
+
+      switch (a)
+      {
+      case perform_update_id: return &perform_update;
+      case perform_clean_id: return &perform_clean;
+      default: return default_recipe; // Forward to prerequisites.
+      }
+    }
+
+    // The strings used as the map key should be from the extension_pool.
+    // This way we can just compare pointers.
+    //
+    using ext_map = map<const string*, const target_type*>;
+
+    static ext_map
+    build_ext_map (scope& r)
+    {
+      ext_map m;
+
+      if (auto val = r["h.ext"])
+        m[&extension_pool.find (val.as<const string&> ())] = &h::static_type;
+
+      if (auto val = r["c.ext"])
+        m[&extension_pool.find (val.as<const string&> ())] = &c::static_type;
+
+      if (auto val = r["hxx.ext"])
+        m[&extension_pool.find (val.as<const string&> ())] = &hxx::static_type;
+
+      if (auto val = r["ixx.ext"])
+        m[&extension_pool.find (val.as<const string&> ())] = &ixx::static_type;
+
+      if (auto val = r["txx.ext"])
+        m[&extension_pool.find (val.as<const string&> ())] = &txx::static_type;
+
+      if (auto val = r["cxx.ext"])
+        m[&extension_pool.find (val.as<const string&> ())] = &cxx::static_type;
+
+      return m;
+    }
+
+    // Mapping of include prefixes (e.g., foo in <foo/bar>) for auto-
+    // generated headers to directories where they will be generated.
+    //
+    // We are using a prefix map of directories (dir_path_map) instead
+    // of just a map in order also cover sub-paths (e.g., <foo/more/bar>
+    // if we continue with the example). Specifically, we need to make
+    // sure we don't treat foobar as a sub-directory of foo.
+    //
+    // @@ The keys should be canonicalized.
+    //
+    using prefix_map = dir_path_map<dir_path>;
+
+    static void
+    append_prefixes (prefix_map& m, target& t, const char* var)
+    {
+      tracer trace ("cxx::append_prefixes");
+
+      const dir_path& out_base (t.dir);
+      const dir_path& out_root (t.root_scope ().path ());
+
+      if (auto val = t[var])
+      {
+        const list_value& l (val.template as<const list_value&> ());
+
+        // Assume the names have already been vetted by append_options().
+        //
+        for (auto i (l.begin ()), e (l.end ()); i != e; ++i)
+        {
+          // -I can either be in the -Ifoo or -I foo form.
+          //
+          dir_path d;
+          if (i->value == "-I")
+          {
+            if (++i == e)
+              break; // Let the compiler complain.
+
+            d = i->simple () ? dir_path (i->value) : i->dir;
+          }
+          else if (i->value.compare (0, 2, "-I") == 0)
+            d = dir_path (i->value, 2, string::npos);
+          else
+            continue;
+
+          level5 ([&]{trace << "-I '" << d << "'";});
+
+          // If we are relative or not inside our project root, then
+          // ignore.
+          //
+          if (d.relative () || !d.sub (out_root))
+            continue;
+
+          // If the target directory is a sub-directory of the include
+          // directory, then the prefix is the difference between the
+          // two. Otherwise, leave it empty.
+          //
+          // The idea here is to make this "canonical" setup work auto-
+          // magically:
+          //
+          // 1. We include all files with a prefix, e.g., <foo/bar>.
+          // 2. The library target is in the foo/ sub-directory, e.g.,
+          //    /tmp/foo/.
+          // 3. The poptions variable contains -I/tmp.
+          //
+          dir_path p (out_base.sub (d) ? out_base.leaf (d) : dir_path ());
+
+          auto j (m.find (p));
+
+          if (j != m.end ())
+          {
+            if (j->second != d)
+              fail << "duplicate generated dependency prefix '" << p << "'" <<
+                info << "old mapping to " << j->second <<
+                info << "new mapping to " << d;
+          }
+          else
+          {
+            level5 ([&]{trace << "'" << p << "' = '" << d << "'";});
+            m.emplace (move (p), move (d));
+          }
+        }
+      }
+    }
+
+    // Append library prefixes based on the cxx.export.poptions variables
+    // recursively, prerequisite libraries first.
+    //
+    static void
+    append_lib_prefixes (prefix_map& m, target& l)
+    {
+      for (target* t: l.prerequisite_targets)
+      {
+        if (t == nullptr)
+          continue;
+
+        if (t->is_a<lib> () || t->is_a<liba> () || t->is_a<libso> ())
+          append_lib_prefixes (m, *t);
+      }
+
+      append_prefixes (m, l, "cxx.export.poptions");
+    }
+
+    static prefix_map
+    build_prefix_map (target& t)
+    {
+      prefix_map m;
+
+      // First process the include directories from prerequisite
+      // libraries. Note that here we don't need to see group
+      // members (see apply()).
+      //
+      for (prerequisite& p: group_prerequisites (t))
+      {
+        target& pt (*p.target); // Already searched and matched.
+
+        if (pt.is_a<lib> () || pt.is_a<liba> () || pt.is_a<libso> ())
+          append_lib_prefixes (m, pt);
+      }
+
+      // Then process our own.
+      //
+      append_prefixes (m, t, "cxx.poptions");
+
+      return m;
+    }
+
+    // Return the next make prerequisite starting from the specified
+    // position and update position to point to the start of the
+    // following prerequisite or l.size() if there are none left.
+    //
+    static string
+    next (const string& l, size_t& p)
+    {
+      size_t n (l.size ());
+
+      // Skip leading spaces.
+      //
+      for (; p != n && l[p] == ' '; p++) ;
+
+      // Lines containing multiple prerequisites are 80 characters max.
+      //
+      string r;
+      r.reserve (n);
+
+      // Scan the next prerequisite while watching out for escape sequences.
+      //
+      for (; p != n && l[p] != ' '; p++)
+      {
+        char c (l[p]);
+
+        if (c == '\\')
+          c = l[++p];
+
+        r += c;
+      }
+
+      // Skip trailing spaces.
+      //
+      for (; p != n && l[p] == ' '; p++) ;
+
+      // Skip final '\'.
+      //
+      if (p == n - 1 && l[p] == '\\')
+        p++;
+
+      return r;
+    }
+
+    static void
+    inject_prerequisites (action a, target& t, cxx& s, scope& ds)
+    {
+      tracer trace ("cxx::compile::inject_prerequisites");
+
+      scope& rs (t.root_scope ());
+      const string& cxx (rs["config.cxx"].as<const string&> ());
+
+      cstrings args {cxx.c_str ()};
+
+      // Add cxx.export.poptions from prerequisite libraries. Note
+      // that here we don't need to see group members (see apply()).
+      //
+      for (prerequisite& p: group_prerequisites (t))
+      {
+        target& pt (*p.target); // Already searched and matched.
+
+        if (pt.is_a<lib> () || pt.is_a<liba> () || pt.is_a<libso> ())
+          append_lib_options (args, pt, "cxx.export.poptions");
+      }
+
+      append_options (args, t, "cxx.poptions");
+
+      // @@ Some C++ options (e.g., -std, -m) affect the preprocessor.
+      // Or maybe they are not C++ options? Common options?
+      //
+      append_options (args, t, "cxx.coptions");
+
+      string std; // Storage.
+      append_std (args, t, std);
+
+      if (t.is_a<objso> ())
+        args.push_back ("-fPIC");
+
+      args.push_back ("-M");  // Note: -MM -MG skips missing <>-included.
+      args.push_back ("-MG"); // Treat missing headers as generated.
+      args.push_back ("-MQ"); // Quoted target name.
+      args.push_back ("*");   // Old versions can't handle empty target name.
+
+      // We are using absolute source file path in order to get absolute
+      // paths in the result. Any relative paths in the result are non-
+      // existent, potentially auto-generated headers.
+      //
+      // @@ We will also have to use absolute -I paths to guarantee
+      // that. Or just detect relative paths and error out?
+      //
+      args.push_back (s.path ().string ().c_str ());
+      args.push_back (nullptr);
+
+      level5 ([&]{trace << "target: " << t;});
+
+      // Build the prefix map lazily only if we have non-existent files.
+      // Also reuse it over restarts since it doesn't change.
+      //
+      prefix_map pm;
+
+      // If any prerequisites that we have extracted changed, then we
+      // have to redo the whole thing. The reason for this is auto-
+      // generated headers: the updated header may now include a yet-
+      // non-existent header. Unless we discover this and generate it
+      // (which, BTW, will trigger another restart since that header,
+      // in turn, can also include auto-generated headers), we will
+      // end up with an error during compilation proper.
+      //
+      // One complication with this restart logic is that we will see
+      // a "prefix" of prerequisites that we have already processed
+      // (i.e., they are already in our prerequisite_targets list) and
+      // we don't want to keep redoing this over and over again. One
+      // thing to note, however, is that the prefix that we have seen
+      // on the previous run must appear exactly the same in the
+      // subsequent run. The reason for this is that none of the files
+      // that it can possibly be based on have changed and thus it
+      // should be exactly the same. To put it another way, the
+      // presence or absence of a file in the dependency output can
+      // only depend on the previous files (assuming the compiler
+      // outputs them as it encounters them and it is hard to think
+      // of a reason why would someone do otherwise). And we have
+      // already made sure that all those files are up to date. And
+      // here is the way we are going to exploit this: we are going
+      // to keep track of how many prerequisites we have processed so
+      // far and on restart skip right to the next one.
+      //
+      // Also, before we do all that, make sure the source file itself
+      // if up to date.
+      //
+      execute_direct (a, s);
+
+      size_t skip_count (0);
+      for (bool restart (true); restart; )
+      {
+        restart = false;
+
+        if (verb >= 2)
+          print_process (args);
+
+        try
+        {
+          process pr (args.data (), false, false, true);
+          ifdstream is (pr.in_ofd);
+
+          size_t skip (skip_count);
+          for (bool first (true), second (true); !(restart || is.eof ()); )
+          {
+            string l;
+            getline (is, l);
+
+            if (is.fail () && !is.eof ())
+              fail << "error reading C++ compiler -M output";
+
+            size_t pos (0);
+
+            if (first)
+            {
+              // Empty output should mean the wait() call below will return
+              // false.
+              //
+              if (l.empty ())
+                break;
+
+              assert (l[0] == '*' && l[1] == ':' && l[2] == ' ');
+
+              first = false;
+
+              // While normally we would have the source file on the
+              // first line, if too long, it will be moved to the next
+              // line and all we will have on this line is "*: \".
+              //
+              if (l.size () == 4 && l[3] == '\\')
+                continue;
+              else
+                pos = 3; // Skip "*: ".
+
+              // Fall through to the 'second' block.
+            }
+
+            if (second)
+            {
+              second = false;
+              next (l, pos); // Skip the source file.
+            }
+
+            // If things go wrong (and they often do in this area), give
+            // the user a bit extra context.
+            //
+            auto g (
+              make_exception_guard (
+                [](target& s)
+                {
+                  info << "while extracting dependencies from " << s;
+                },
+                s));
+
+            while (pos != l.size ())
+            {
+              string fs (next (l, pos));
+
+              // Skip until where we left off.
+              //
+              if (skip != 0)
+              {
+                skip--;
+                continue;
+              }
+
+              path f (move (fs));
+              f.normalize ();
+
+              if (!f.absolute ())
+              {
+                // This is probably as often an error as an auto-generated
+                // file, so trace at level 3.
+                //
+                level3 ([&]{trace << "non-existent header '" << f << "'";});
+
+                // If we already did it and build_prefix_map() returned empty,
+                // then we would have failed below.
+                //
+                if (pm.empty ())
+                  pm = build_prefix_map (t);
+
+                // First try the whole file. Then just the directory.
+                //
+                // @@ Has to be a separate map since the prefix can be
+                //    the same as the file name.
+                //
+                // auto i (pm.find (f));
+
+                // Find the most qualified prefix of which we are a
+                // sub-path.
+                //
+                auto i (pm.end ());
+
+                if (!pm.empty ())
+                {
+                  const dir_path& d (f.directory ());
+                  i = pm.upper_bound (d);
+                  --i; // Greatest less than.
+
+                  if (!d.sub (i->first)) // We might still not be a sub.
+                    i = pm.end ();
+                }
+
+                if (i == pm.end ())
+                  fail << "unable to map presumably auto-generated header '"
+                       << f << "' to a project";
+
+                f = i->second / f;
+              }
+
+              level5 ([&]{trace << "injecting " << f;});
+
+              // Split the name into its directory part, the name part, and
+              // extension. Here we can assume the name part is a valid
+              // filesystem name.
+              //
+              // Note that if the file has no extension, we record an empty
+              // extension rather than NULL (which would signify that the
+              // default extension should be added).
+              //
+              dir_path d (f.directory ());
+              string n (f.leaf ().base ().string ());
+              const char* es (f.extension ());
+              const string* e (&extension_pool.find (es != nullptr ? es : ""));
+
+              // Determine the target type.
+              //
+              const target_type* tt (nullptr);
+
+              // See if this directory is part of any project out_root
+              // hierarchy. Note that this will miss all the headers
+              // that come from src_root (so they will be treated as
+              // generic C headers below). Generally, we don't have
+              // the ability to determine that some file belongs to
+              // src_root of some project. But that's not a problem
+              // for our purposes: it is only important for us to
+              // accurately determine target types for headers that
+              // could be auto-generated.
+              //
+              if (scope* r = scopes.find (d).root_scope ())
+              {
+                // Get cached (or build) a map of the extensions for the
+                // C/C++ files this project is using.
+                //
+                const ext_map& m (build_ext_map (*r));
+
+                auto i (m.find (e));
+                if (i != m.end ())
+                  tt = i->second;
+              }
+
+              // If it is outside any project, or the project doesn't have
+              // such an extension, assume it is a plain old C header.
+              //
+              if (tt == nullptr)
+                tt = &h::static_type;
+
+              // Find or insert target.
+              //
+              path_target& pt (
+                static_cast<path_target&> (search (*tt, d, n, e, &ds)));
+
+              // Assign path.
+              //
+              if (pt.path ().empty ())
+                pt.path (move (f));
+
+              // Match to a rule.
+              //
+              build::match (a, pt);
+
+              // Update it.
+              //
+              // There would normally be a lot of headers for every source
+              // file (think all the system headers) and this can get
+              // expensive. At the same time, most of these headers are
+              // existing files that we will never be updating (again,
+              // system headers, for example) and the rule that will match
+              // them is fallback file_rule. So we are going to do a little
+              // fast-path optimization by detecting this common case.
+              //
+              recipe_function* const* recipe (
+                pt.recipe (a).target<recipe_function*> ());
+
+              if (recipe == nullptr || *recipe != &file_rule::perform_update)
+              {
+                // We only want to restart if our call to execute() actually
+                // caused an update. In particular, the target could already
+                // have been in target_state::changed because of a dependency
+                // extraction run for some other source file.
+                //
+                target_state os (pt.state ());
+                target_state ns (execute_direct (a, pt));
+
+                if (ns != os && ns != target_state::unchanged)
+                {
+                  level5 ([&]{trace << "updated " << pt << ", restarting";});
+                  restart = true;
+                }
+              }
+
+              // Add to our prerequisite target list.
+              //
+              t.prerequisite_targets.push_back (&pt);
+              skip_count++;
+            }
+          }
+
+          // We may not have read all the output (e.g., due to a restart),
+          // so close the file descriptor before waiting to avoid blocking
+          // the other end.
+          //
+          is.close ();
+
+          // We assume the child process issued some diagnostics.
+          //
+          if (!pr.wait ())
+            throw failed ();
+        }
+        catch (const process_error& e)
+        {
+          error << "unable to execute " << args[0] << ": " << e.what ();
+
+          // In a multi-threaded program that fork()'ed but did not exec(),
+          // it is unwise to try to do any kind of cleanup (like unwinding
+          // the stack and running destructors).
+          //
+          if (e.child ())
+            exit (1);
+
+          throw failed ();
+        }
+      }
+    }
+
+    target_state compile::
+    perform_update (action a, target& xt)
+    {
+      path_target& t (static_cast<path_target&> (xt));
+      cxx* s (execute_prerequisites<cxx> (a, t, t.mtime ()));
+
+      if (s == nullptr)
+        return target_state::unchanged;
+
+      // Translate paths to relative (to working directory) ones. This
+      // results in easier to read diagnostics.
+      //
+      path relo (relative (t.path ()));
+      path rels (relative (s->path ()));
+
+      scope& rs (t.root_scope ());
+      const string& cxx (rs["config.cxx"].as<const string&> ());
+
+      cstrings args {cxx.c_str ()};
+
+      // Add cxx.export.poptions from prerequisite libraries. Note that
+      // here we don't need to see group members (see apply()).
+      //
+      for (prerequisite& p: group_prerequisites (t))
+      {
+        target& pt (*p.target); // Already searched and matched.
+
+        if (pt.is_a<lib> () || pt.is_a<liba> () || pt.is_a<libso> ())
+          append_lib_options (args, pt, "cxx.export.poptions");
+      }
+
+      append_options (args, t, "cxx.poptions");
+      append_options (args, t, "cxx.coptions");
+
+      string std; // Storage.
+      append_std (args, t, std);
+
+      if (t.is_a<objso> ())
+        args.push_back ("-fPIC");
+
+      args.push_back ("-o");
+      args.push_back (relo.string ().c_str ());
+
+      args.push_back ("-c");
+      args.push_back (rels.string ().c_str ());
+
+      args.push_back (nullptr);
+
+      if (verb)
+        print_process (args);
+      else
+        text << "c++ " << *s;
+
+      try
+      {
+        process pr (args.data ());
+
+        if (!pr.wait ())
+          throw failed ();
+
+        // Should we go to the filesystem and get the new mtime? We
+        // know the file has been modified, so instead just use the
+        // current clock time. It has the advantage of having the
+        // subseconds precision.
+        //
+        t.mtime (system_clock::now ());
+        return target_state::changed;
+      }
+      catch (const process_error& e)
+      {
+        error << "unable to execute " << args[0] << ": " << e.what ();
+
+        // In a multi-threaded program that fork()'ed but did not exec(),
+        // it is unwise to try to do any kind of cleanup (like unwinding
+        // the stack and running destructors).
+        //
+        if (e.child ())
+          exit (1);
+
+        throw failed ();
+      }
+    }
+  }
+}