GN: Makes GN output deterministic

tools/gn/target.cc

Index: tools/gn/target.cc
diff --git a/tools/gn/target.cc b/tools/gn/target.cc
index 4a93abc240cd36655d24a9ec8e0a9d52749e8543..5dfd06479dbf9a87a645cad03caea4d344eb0a0c 100644
--- a/tools/gn/target.cc
+++ b/tools/gn/target.cc
@@ -10,6 +10,7 @@
 #include "tools/gn/config_values_extractors.h"
 #include "tools/gn/deps_iterator.h"
 #include "tools/gn/filesystem_utils.h"
+#include "tools/gn/pointer_set.h"
 #include "tools/gn/scheduler.h"
 #include "tools/gn/substitution_writer.h"
 #include "tools/gn/trace.h"
@@ -70,7 +71,7 @@ Err MakeStaticLibDepsError(const Target* from, const Target* to) {
 bool EnsureFileIsGeneratedByDependency(const Target* target,
                                        const OutputFile& file,
                                        bool check_private_deps,
-                                       std::set<const Target*>* seen_targets) {
+                                       PointerSet<const Target>* seen_targets) {
   if (seen_targets->find(target) != seen_targets->end())
     return false;  // Already checked this one and it's not found.
   seen_targets->insert(target);
@@ -548,7 +549,11 @@ void Target::CheckSourceGenerated(const SourceFile& source) const {
   // the list of files written by the GN build itself (often response files)
   // can be filtered out of this list.
   OutputFile out_file(settings()->build_settings(), source);
-  std::set<const Target*> seen_targets;
+  PointerSet<const Target> seen_targets;
   if (!EnsureFileIsGeneratedByDependency(this, out_file, true, &seen_targets))
     g_scheduler->AddUnknownGeneratedInput(this, source);
 }
+
+bool Target::operator<(const Target& other) const {

[mithro-old, 2015/12/03 05:20:31]

I'm unsure if we want an implicit less than operator. Check with the gn
developers if they are okay with this.

[Zachary Forman, 2015/12/03 07:27:02]

Acknowledged.

I'll leave this for the GN developers to comment on - my thought is that a
target (or perhaps, rather, an item) has
a natural ordering based on the label.

+  return label() < other.label();
+}