GN: Refine 'complete' static library handling

tools/gn/ninja_binary_target_writer.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/ninja_binary_target_writer.h"
 
 #include <stddef.h>
 #include <string.h>
 
 #include <cstring>
@@ skipping 920 matching lines @@
   // Only the following types of outputs have libraries linked into them:
   //  EXECUTABLE
   //  SHARED_LIBRARY
   //  _complete_ STATIC_LIBRARY
   //
   // Child deps of intermediate static libraries get pushed up the
   // dependency tree until one of these is reached, and source sets
   // don't link at all.
   bool can_link_libs = target_->IsFinal();
 
-  if (dep->output_type() == Target::SOURCE_SET) {
+  if (dep->output_type() == Target::SOURCE_SET ||
+      // If a complete static library depends on an incomplete static library,
+      // manually link in the object files of the dependent library as if it
+      // were a source set. This avoids problems with braindead tools such as
+      // ar which don't properly link dependent static libraries.
+      (target_->complete_static_lib() &&
+       dep->output_type() == Target::STATIC_LIBRARY &&
+       !dep->complete_static_lib())) {
     // Source sets have their object files linked into final targets
     // (shared libraries, executables, loadable modules, and complete static
     // libraries). Intermediate static libraries and other source sets
     // just forward the dependency, otherwise the files in the source
     // set can easily get linked more than once which will cause
     // multiple definition errors.
     if (can_link_libs)
       AddSourceSetObjectFiles(dep, extra_object_files);
-

[brettw, 2016/04/21 20:47:00]

I liked this blank line here as it was before.

     // Add the source set itself as a non-linkable dependency on the current
     // target. This will make sure that anything the source set's stamp file
     // depends on (like data deps) are also built before the current target
     // can be complete. Otherwise, these will be skipped since this target
     // will depend only on the source set's object files.
     non_linkable_deps->push_back(dep);
+  } else if (target_->complete_static_lib() && dep->IsFinal()) {
+    non_linkable_deps->push_back(dep);
   } else if (can_link_libs && dep->IsLinkable()) {
     linkable_deps->push_back(dep);
   } else {
     non_linkable_deps->push_back(dep);
   }
 }
 
 void NinjaBinaryTargetWriter::WriteOrderOnlyDependencies(
     const UniqueVector<const Target*>& non_linkable_deps) {
   if (!non_linkable_deps.empty()) {
@@ skipping 39 matching lines @@
           "\n"
           "In the latter case, either rename one of the files or move one of\n"
           "the sources to a separate source_set to avoid them both being in\n"
           "the same target.");
       g_scheduler->FailWithError(err);
       return false;
     }
   }
   return true;
 }