Implement tracking of BUILD.gn files used to define target, toolchain or

tools/gn/analyzer.cc

Index: tools/gn/analyzer.cc
diff --git a/tools/gn/analyzer.cc b/tools/gn/analyzer.cc
index aa0eca4d1c1c882fe8ede2bb00b81ef7cf8ebce9..c6eb0dc324e7a24e329e53fd8c991e42a1237d7d 100644
--- a/tools/gn/analyzer.cc
+++ b/tools/gn/analyzer.cc
@@ -13,12 +13,12 @@
 #include "base/json/json_writer.h"
 #include "base/memory/ptr_util.h"
 #include "base/strings/string_util.h"
-#include "base/strings/string_util.h"
 #include "base/values.h"
 #include "tools/gn/builder.h"
 #include "tools/gn/deps_iterator.h"
 #include "tools/gn/err.h"
 #include "tools/gn/filesystem_utils.h"
+#include "tools/gn/input_file.h"
 #include "tools/gn/loader.h"
 #include "tools/gn/location.h"
 #include "tools/gn/source_file.h"
@@ -56,17 +56,6 @@ LabelSet LabelsFor(const TargetSet& targets) {
   return labels;
 }
 
-bool AnyBuildFilesWereModified(const SourceFileSet& source_files) {
-  for (auto* file : source_files) {
-    if (base::EndsWith(file->value(), ".gn", base::CompareCase::SENSITIVE) ||
-        base::EndsWith(file->value(), ".gni", base::CompareCase::SENSITIVE) ||
-        base::EndsWith(file->value(), "build/vs_toolchain.py",
-                       base::CompareCase::SENSITIVE))
-      return true;
-  }
-  return false;
-}
-
 TargetSet Intersect(const TargetSet& l, const TargetSet& r) {
   TargetSet result;
   std::set_intersection(l.begin(), l.end(), r.begin(), r.end(),
@@ -225,9 +214,10 @@ std::string OutputsToJSON(const Outputs& outputs,
 
 }  // namespace
 
-Analyzer::Analyzer(const Builder& builder)
+Analyzer::Analyzer(const BuildSettings& build_settings, const Builder& builder)
     : all_targets_(builder.GetAllResolvedTargets()),
-      default_toolchain_(builder.loader()->GetDefaultToolchain()) {
+      default_toolchain_(builder.loader()->GetDefaultToolchain()),
+      build_config_file_(build_settings.build_config_file()) {
   for (const auto* target : all_targets_) {
     labels_to_targets_[target->label()] = target;
     for (const auto& dep_pair : target->GetDeps(Target::DEPS_ALL))
@@ -262,12 +252,7 @@ std::string Analyzer::Analyze(const std::string& input, Err* err) const {
     return OutputsToJSON(outputs, default_toolchain_, err);
   }
 
-  // TODO(crbug.com/555273): We can do smarter things when we detect changes
-  // to build files. For example, if all of the ninja files are unchanged,
-  // we know that we can ignore changes to .gn* files. Also, for most .gn
-  // files, we can treat a change as simply affecting every target, config,
-  // or toolchain defined in that file.
-  if (AnyBuildFilesWereModified(inputs.source_files)) {
+  if (WereMainGNFilesModified(inputs.source_files)) {
     outputs.status = "Found dependency (all)";
     if (inputs.compile_included_all) {
       outputs.compile_includes_all = true;
@@ -360,6 +345,10 @@ void Analyzer::FilterTarget(const Target* target,
 
 bool Analyzer::TargetRefersToFile(const Target* target,
                                   const SourceFile* file) const {
+  for (const auto* cur_file : target->input_files()) {
+    if (cur_file->name() == *file)
+      return true;
+  }
   for (const auto& cur_file : target->sources()) {
     if (cur_file == *file)
       return true;
@@ -410,3 +399,12 @@ void Analyzer::AddAllRefsTo(const Target* target, TargetSet* results) const {
   for (auto cur_dep = dep_begin; cur_dep != dep_end; cur_dep++)
     AddAllRefsTo(cur_dep->second, results);
 }
+
+bool Analyzer::WereMainGNFilesModified(
+    const SourceFileSet& source_files) const {
+  for (auto* file : source_files) {
+    if (file->value() == "//.gn" || *file == build_config_file_)

[brettw, 2017/06/28 20:49:40]

Somewhat annoyingly, the dotfile can be overridden on the command line. This was
used by nacl (not sure if it still is) and some other projects that wanted to be
DEPSed in in weird ways. I think we will still want to support this.

Setup has a dotfile_name_ member that we can expose a getter for and pass to the
analyzer. The annoying thing will be that this is a base::FilePath. I think we
can call SourceDir.ResolveRelativeFile with the UTF-8 version of the
base::FilePath to convert here. You can use "//" for the SourceDir to resolve
against (the input should be absolute).

[alex-ac, 2017/06/29 10:26:57]

Done.

+      return true;
+  }
+  return false;
+}