Add tags field to build.

The tags field is a string with an implementation defined format. This
allows build systems to include arbitrary metadata in the proto for
better metrics.

Bug: http://b/259130368
Test: used to trace dist cp time
Change-Id: I9f6fcae0d8e4f7152ea82d3038807f622ca92801

6 files changed, 28 insertions, 0 deletions

diff --git a/frontend/frontend.pb b/frontend/frontend.pb
index f35d673..8795ecd 100644
--- a/frontend/frontend.pb
+++ b/frontend/frontend.pb
diff --git a/src/frontend.pb.h b/src/frontend.pb.h
index 5b3ac26..d5474a1 100644
--- a/src/frontend.pb.h
+++ b/src/frontend.pb.h
@@ -289,6 +289,8 @@ struct Status {
     bool has_voluntary_context_switches_;
     uint64_t involuntary_context_switches_;
     bool has_involuntary_context_switches_;
+    std::string tags_;
+    bool has_tags_;
 
     EdgeFinished() {
       has_id_ = false;
@@ -316,6 +318,7 @@ struct Status {
       voluntary_context_switches_ = static_cast< uint64_t >(0);
       has_involuntary_context_switches_ = false;
       involuntary_context_switches_ = static_cast< uint64_t >(0);
+      has_tags_ = false;
     }
 
     EdgeFinished(const EdgeFinished&);
@@ -335,6 +338,7 @@ struct Status {
       WriteVarint64(output__, 11, io_output_kb_);
       WriteVarint64(output__, 12, voluntary_context_switches_);
       WriteVarint64(output__, 13, involuntary_context_switches_);
+      WriteString(output__, 14, tags_);
     }
 
     size_t ByteSizeLong() const {
@@ -352,6 +356,7 @@ struct Status {
       size += VarintSize64(io_output_kb_) + 1;
       size += VarintSize64(voluntary_context_switches_) + 1;
       size += VarintSize64(involuntary_context_switches_) + 1;
+      size += StringSize(tags_) + 1;
       return size;
     }
 
@@ -369,6 +374,7 @@ struct Status {
       io_output_kb_ = static_cast< uint64_t >(0);
       voluntary_context_switches_ = static_cast< uint64_t >(0);
       involuntary_context_switches_ = static_cast< uint64_t >(0);
+      tags_.clear();
     }
 
     uint32_t* mutable_id() {
@@ -475,6 +481,14 @@ struct Status {
       has_involuntary_context_switches_ = true;
       involuntary_context_switches_ = value;
     }
+    std::string* mutable_tags() {
+      has_tags_ = true;
+      return &tags_;
+    }
+    void set_tags(const std::string& value) {
+      has_tags_ = true;
+      tags_ = value;
+    }
   };
 
   struct Message {
diff --git a/src/frontend.proto b/src/frontend.proto
index 8f03522..45b428a 100644
--- a/src/frontend.proto
+++ b/src/frontend.proto
@@ -78,6 +78,9 @@ message Status {
     optional uint64 voluntary_context_switches = 12;
     // Involuntary context switches
     optional uint64 involuntary_context_switches = 13;
+    // Arbitrary tags for build system profiling (module names and types, rule
+    // names, etc). Format of the string is implementation defined.
+    optional string tags = 14;
   }
 
   message Message {
diff --git a/src/graph.h b/src/graph.h
index 85e9326..04bbf84 100644
--- a/src/graph.h
+++ b/src/graph.h
@@ -470,6 +470,7 @@ public:
   bool deps_missing_ = false;
   bool phony_from_depfile_ = false;
   DepScanInfo dep_scan_info_;
+  std::string tags_;
 
   DeclIndex dfs_location() const { return pos_.dfs_location(); }
   const Rule& rule() const { return *rule_; }
diff --git a/src/manifest_parser.cc b/src/manifest_parser.cc
index 45342eb..f84d523 100644
--- a/src/manifest_parser.cc
+++ b/src/manifest_parser.cc
@@ -414,6 +414,7 @@ static inline bool AddPathToEdge(State* state, const Edge& edge,
 static const HashedStrView kPool { "pool" };
 static const HashedStrView kDeps { "deps" };
 static const HashedStrView kDyndep { "dyndep" };
+static const HashedStrView kTags { "tags" };
 
 struct ManifestLoader {
 private:
@@ -468,6 +469,14 @@ bool ManifestLoader::AddEdgeToGraph(Edge* edge, const LoadedFile& file,
     }
   }
 
+  std::string tags;
+  if (!edge->EvaluateVariable(&tags, kTags, edge->pos_.scope(), err, EdgeEval::kParseTime)) {
+    return false;
+  }
+  if (!tags.empty()) {
+    edge->tags_ = tags;
+  }
+
   edge->outputs_.reserve(edge->explicit_outs_ + edge->implicit_outs_);
   edge->inputs_.reserve(edge->explicit_deps_ + edge->implicit_deps_ +
                         edge->order_only_deps_);
diff --git a/src/status.cc b/src/status.cc
index 1049312..445771b 100644
--- a/src/status.cc
+++ b/src/status.cc
@@ -377,6 +377,7 @@ void StatusSerializer::BuildEdgeFinished(Edge* edge, int64_t end_time_millis,
   edge_finished->set_io_output_kb(result->rusage.ru_oublock / 2);
   edge_finished->set_voluntary_context_switches(result->rusage.ru_nvcsw);
   edge_finished->set_involuntary_context_switches(result->rusage.ru_nivcsw);
+  edge_finished->set_tags(edge->tags_);
 
   Send();
 }