Use depdb to track changes to cli compiler, options, etc

4 files changed, 123 insertions, 22 deletions

diff --git a/build2/algorithm.cxx b/build2/algorithm.cxx
index 5dc3637..c46e878 100644
--- a/build2/algorithm.cxx
+++ b/build2/algorithm.cxx
@@ -2056,4 +2056,33 @@ namespace build2
     r |= reverse_execute_prerequisites (a, g);
     return r;
   }
+
+  target_state
+  perform_clean_group_depdb (action a, const target& g)
+  {
+    // The same twisted target state merging logic as in clean_extra().
+    //
+    target_state er (target_state::unchanged);
+    path ep;
+
+    group_view gv (g.group_members (a));
+    if (gv.count != 0)
+    {
+      ep = gv.members[0]->as<file> ().path () + ".d";
+
+      if (rmfile (ep, 3))
+        er = target_state::changed;
+    }
+
+    target_state tr (perform_clean_group (a, g));
+
+    if (tr != target_state::changed && er == target_state::changed)
+    {
+      if (verb > (current_diag_noise ? 0 : 1) && verb < 3)
+        text << "rm " << ep;
+    }
+
+    tr |= er;
+    return tr;
+  }
 }
diff --git a/build2/algorithm.hxx b/build2/algorithm.hxx
index 48f48c8..93fe131 100644
--- a/build2/algorithm.hxx
+++ b/build2/algorithm.hxx
@@ -616,6 +616,12 @@ namespace build2
   target_state
   perform_clean_group (action, const target&);
 
+  // As above but clean both the target group and depdb. The depdb file path
+  // is derived from the first member file path.
+  //
+  target_state
+  perform_clean_group_depdb (action, const target&);
+
   // Helper for custom perform(clean) implementations that cleans extra files
   // and directories (recursively) specified as a list of either absolute
   // paths or "path derivation directives". The directive string can be NULL,
diff --git a/build2/cli/init.cxx b/build2/cli/init.cxx
index 88a8d69..8e0abdb 100644
--- a/build2/cli/init.cxx
+++ b/build2/cli/init.cxx
@@ -53,7 +53,11 @@ namespace build2
         v.insert<path>    ("config.cli",         true);
         v.insert<strings> ("config.cli.options", true);
 
+        //@@ TODO: split version into componets (it is stdver).
+        //
         v.insert<process_path> ("cli.path");
+        v.insert<string>       ("cli.version");
+        v.insert<string>       ("cli.checksum");
         v.insert<strings>      ("cli.options");
       }
 
@@ -214,11 +218,23 @@ namespace build2
           nv = p.second;
         }
 
-        // Note that we are unconfigured so that we don't keep re-testing this
-        // on each run.
-        //
-        if (!conf)
+        string checksum;
+        if (conf)
+        {
+          // Hash the compiler path and version.
+          //
+          sha256 cs;
+          cs.append (pp.effect_string ());
+          cs.append (ver);
+          checksum = cs.string ();
+        }
+        else
+        {
+          // Note that we are unconfigured so that we don't keep re-testing
+          // this on each run.
+          //
           nv = config::unconfigured (rs, "cli", true) || nv;
+        }
 
         // If this is a new value (e.g., we are configuring), then print the
         // report at verbosity level 2 and up (-v).
@@ -230,13 +246,18 @@ namespace build2
 
           if (conf)
             dr << "  cli        " << pp << '\n'
-               << "  version    " << ver;
+               << "  version    " << ver << '\n'
+               << "  checksum   " << checksum;
           else
             dr << "  cli        " << "not found, leaving unconfigured";
         }
 
         if (conf)
-          rs.assign<process_path> ("cli.path") = move (pp);
+        {
+          rs.assign ("cli.path")     = move (pp);
+          rs.assign ("cli.version")  = move (ver);
+          rs.assign ("cli.checksum") = move (checksum);
+        }
       }
 
       if (conf)
diff --git a/build2/cli/rule.cxx b/build2/cli/rule.cxx
index 45b8185..27668c1 100644
--- a/build2/cli/rule.cxx
+++ b/build2/cli/rule.cxx
@@ -4,6 +4,7 @@
 
 #include <build2/cli/rule.hxx>
 
+#include <build2/depdb.hxx>
 #include <build2/scope.hxx>
 #include <build2/target.hxx>
 #include <build2/context.hxx>
@@ -166,10 +167,12 @@ namespace build2
         //
         match_prerequisite_members (a, t);
 
+        //@@ TODO: inject dependency on exe{cli}.
+
         switch (a)
         {
         case perform_update_id: return &perform_update;
-        case perform_clean_id:  return &perform_clean_group; // Standard impl.
+        case perform_clean_id:  return &perform_clean_group_depdb;
         default:                return noop_recipe; // Configure/dist update.
         }
       }
@@ -206,34 +209,76 @@ namespace build2
     target_state compile_rule::
     perform_update (action a, const target& xt)
     {
+      tracer trace ("cli::compile_rule::perform_update");
+
+      // The rule has been matched which means the members should be resolved
+      // and paths assigned. We use the header file as our "target path" for
+      // timestamp, depdb, etc.
+      //
       const cli_cxx& t (xt.as<cli_cxx> ());
+      const scope& rs (t.root_scope ());
+      const path& tp (t.h->path ());
 
       // Update prerequisites and determine if any relevant ones render us
-      // out-of-date. Note that currently we treat all the prerequisites
-      // as potentially affecting the result (think prologues/epilogues,
-      // etc).
+      // out-of-date. Note that currently we treat all the prerequisites as
+      // potentially affecting the result (think prologues/epilogues, etc).
       //
+      timestamp mt (t.load_mtime (tp));
+      auto pr (execute_prerequisites<cli> (a, t, mt));
 
-      // The rule has been matched which means the members should be resolved
-      // and paths assigned.
+      bool update (!pr.first);
+      target_state ts (update ? target_state::changed : *pr.first);
+
+      const cli& s (pr.second);
+
+      // We use depdb to track changes to the .cli file name, options,
+      // compiler, etc.
       //
-      auto pr (
-        execute_prerequisites<cli> (
-          a, t, t.load_mtime (t.h->path ())));
+      {
+        depdb dd (tp + ".d");
 
-      if (pr.first)
-        return *pr.first;
+        // First should come the rule name/version.
+        //
+        if (dd.expect ("cli.compile 1") != nullptr)
+          l4 ([&]{trace << "rule mismatch forcing update of " << t;});
 
-      const cli& s (pr.second);
+        // Then the compiler checksum.
+        //
+        if (dd.expect (cast<string> (rs["cli.checksum"])) != nullptr)
+          l4 ([&]{trace << "compiler mismatch forcing update of " << t;});
 
-      // Translate paths to relative (to working directory). This
-      // results in easier to read diagnostics.
+        // Then the options checksum.
+        //
+        sha256 cs;
+        hash_options (cs, t, "cli.options");
+
+        if (dd.expect (cs.string ()) != nullptr)
+          l4 ([&]{trace << "options mismatch forcing update of " << t;});
+
+        // Finally the .cli input file.
+        //
+        if (dd.expect (s.path ()) != nullptr)
+          l4 ([&]{trace << "input file mismatch forcing update of " << t;});
+
+        // Update if depdb mismatch.
+        //
+        if (dd.writing () || dd.mtime () > mt)
+          update = true;
+
+        dd.close ();
+      }
+
+      // If nothing changed, then we are done.
+      //
+      if (!update)
+        return ts;
+
+      // Translate paths to relative (to working directory). This results in
+      // easier to read diagnostics.
       //
       path relo (relative (t.dir));
       path rels (relative (s.path ()));
 
-      const scope& rs (t.root_scope ());
-
       const process_path& cli (cast<process_path> (rs["cli.path"]));
 
       cstrings args {cli.recall_string ()};