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

tools/gn/analyzer.cc

 // Copyright 2016 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/analyzer.h"
 
 #include <algorithm>
 #include <iterator>
 #include <set>
 #include <vector>
@@ skipping 38 matching lines @@
   LabelSet invalid_labels;
 };
 
 LabelSet LabelsFor(const TargetSet& targets) {
   LabelSet labels;
   for (auto* target : targets)
     labels.insert(target->label());
   return labels;
 }
 
-bool AnyBuildFilesWereModified(const SourceFileSet& source_files) {
+bool DotGNFileWasModified(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))
+    if (file->value() == "//.gn")
       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(),
                         std::inserter(result, result.begin()));
   return result;
@@ skipping 180 matching lines @@
   for (const auto& label : InvalidLabels(inputs.compile_labels))
     invalid_labels.insert(label);
   for (const auto& label : InvalidLabels(inputs.test_labels))
     invalid_labels.insert(label);
   if (!invalid_labels.empty()) {
     outputs.error = "Invalid targets";
     outputs.invalid_labels = invalid_labels;
     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 (DotGNFileWasModified(inputs.source_files)) {
     outputs.status = "Found dependency (all)";
     if (inputs.compile_included_all) {
       outputs.compile_includes_all = true;
     } else {
       outputs.compile_labels.insert(inputs.compile_labels.begin(),
                                     inputs.compile_labels.end());
       outputs.compile_labels.insert(inputs.test_labels.begin(),
                                     inputs.test_labels.end());
     }
     outputs.test_labels = inputs.test_labels;
@@ skipping 72 matching lines @@
       filtered->insert(target);
     } else {
       for (const auto& pair : target->GetDeps(Target::DEPS_ALL))
         FilterTarget(pair.ptr, seen, filtered);
     }
   }
 }
 
 bool Analyzer::TargetRefersToFile(const Target* target,
                                   const SourceFile* file) const {
+  const auto& source_files_hashes = target->source_files_hashes();
+  if (source_files_hashes.find(base::Hash(file->value())) !=
+      source_files_hashes.end())
+    return true;
   for (const auto& cur_file : target->sources()) {
     if (cur_file == *file)
       return true;
   }
   for (const auto& cur_file : target->public_headers()) {
     if (cur_file == *file)
       return true;
   }
   for (const auto& cur_file : target->inputs()) {
     if (cur_file == *file)
@@ skipping 30 matching lines @@
 void Analyzer::AddAllRefsTo(const Target* target, TargetSet* results) const {
   if (results->find(target) != results->end())
     return;  // Already found this target.
   results->insert(target);
 
   auto dep_begin = dep_map_.lower_bound(target);
   auto dep_end = dep_map_.upper_bound(target);
   for (auto cur_dep = dep_begin; cur_dep != dep_end; cur_dep++)
     AddAllRefsTo(cur_dep->second, results);
 }