GN: only write targets that should be generated.

tools/gn/builder.cc

 // Copyright (c) 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "tools/gn/builder.h"
 
 #include <stddef.h>
 #include <utility>
 
 #include "tools/gn/config.h"
@@ skipping 386 matching lines @@
       BuilderRecord::ITEM_TOOLCHAIN, err);
   if (!toolchain_record)
     return false;
   record->AddDep(toolchain_record);
 
   return true;
 }
 
 void Builder::RecursiveSetShouldGenerate(BuilderRecord* record,
                                          bool force) {
-  if (!force && record->should_generate())
-    return;  // Already set.
-  record->set_should_generate(true);
+  if (!record->should_generate()) {
+    record->set_should_generate(true);
+
+    // This may have caused the item to go into "resolved and generated" state.
+    if (record->resolved() && !resolved_and_generated_callback_.is_null())
+      resolved_and_generated_callback_.Run(record);
+  } else if (!force) {
+    return;  // Already set and we're not required to iterate dependencies.
+  }
 
   for (auto* cur : record->all_deps()) {
     if (!cur->should_generate()) {
       ScheduleItemLoadIfNecessary(cur);
       RecursiveSetShouldGenerate(cur, false);
     }
   }
 }
 
 void Builder::ScheduleItemLoadIfNecessary(BuilderRecord* record) {
@@ skipping 24 matching lines @@
     if (!ResolveDeps(&toolchain->deps(), err))
       return false;
     if (!ResolvePools(toolchain, err))
       return false;
   }
 
   record->set_resolved(true);
 
   if (!record->item()->OnResolved(err))
     return false;
-  if (!resolved_callback_.is_null())
-    resolved_callback_.Run(record);
+  if (record->should_generate() && !resolved_and_generated_callback_.is_null())
+    resolved_and_generated_callback_.Run(record);
 
   // Recursively update everybody waiting on this item to be resolved.
   for (BuilderRecord* waiting : record->waiting_on_resolution()) {
     DCHECK(waiting->unresolved_deps().find(record) !=
            waiting->unresolved_deps().end());
     waiting->unresolved_deps().erase(record);
 
     if (waiting->can_resolve()) {
       if (!ResolveItem(waiting, err))
         return false;
@@ skipping 79 matching lines @@
   std::string ret;
   for (size_t i = 0; i < cycle.size(); i++) {
     ret += "  " + cycle[i]->label().GetUserVisibleName(false);
     if (i != cycle.size() - 1)
       ret += " ->";
     ret += "\n";
   }
 
   return ret;
 }