commit 325602ca41c76753470b991c7a47b76b15e4241b
author Brad King <brad.king@kitware.com> Mon Nov 30 13:56:04 2015 -0500
committer Brad King <brad.king@kitware.com> Thu Apr 18 08:21:44 2019 -0400
tree 3a0fe810e629519ca8ba32510c515827e08eb852
parent b08f3fb86909bf5b890e33936cf8fd44e1cbff47

Explicitly avoid repeat deps loading

Track for each Edge whether depfile information has been loaded using an
explicit flag.  This will allow RecomputeDirty to be repeated for an
edge without loading deps again.

src/graph.cc

diff --git a/src/graph.cc b/src/graph.cc
index 9c2f784..bf9363d 100644
--- a/src/graph.cc
+++ b/src/graph.cc
@@ -75,12 +75,16 @@
       return false;
   }
 
-  if (!dep_loader_.LoadDeps(edge, err)) {
-    if (!err->empty())
-      return false;
-    // Failed to load dependency info: rebuild to regenerate it.
-    // LoadDeps() did EXPLAIN() already, no need to do it here.
-    dirty = edge->deps_missing_ = true;
+  if (!edge->deps_loaded_) {
+    // This is our first encounter with this edge.  Load discovered deps.
+    edge->deps_loaded_ = true;
+    if (!dep_loader_.LoadDeps(edge, err)) {
+      if (!err->empty())
+        return false;
+      // Failed to load dependency info: rebuild to regenerate it.
+      // LoadDeps() did EXPLAIN() already, no need to do it here.
+      dirty = edge->deps_missing_ = true;
+    }
   }
 
   // Visit all inputs; we're dirty if any of the inputs are dirty.

src/graph.h

diff --git a/src/graph.h b/src/graph.h
index d58fecd..20af578 100644
--- a/src/graph.h
+++ b/src/graph.h
@@ -136,7 +136,7 @@
   };
 
   Edge() : rule_(NULL), pool_(NULL), env_(NULL), mark_(VisitNone),
-           outputs_ready_(false), deps_missing_(false),
+           outputs_ready_(false), deps_loaded_(false), deps_missing_(false),
            implicit_deps_(0), order_only_deps_(0), implicit_outs_(0) {}
 
   /// Return true if all inputs' in-edges are ready.
@@ -165,6 +165,7 @@
   BindingEnv* env_;
   VisitMark mark_;
   bool outputs_ready_;
+  bool deps_loaded_;
   bool deps_missing_;
 
   const Rule& rule() const { return *rule_; }

src/state.cc

diff --git a/src/state.cc b/src/state.cc
index 9b3c7e1..74cf4c1 100644
--- a/src/state.cc
+++ b/src/state.cc
@@ -186,6 +186,7 @@
     i->second->ResetState();
   for (vector<Edge*>::iterator e = edges_.begin(); e != edges_.end(); ++e) {
     (*e)->outputs_ready_ = false;
+    (*e)->deps_loaded_ = false;
     (*e)->mark_ = Edge::VisitNone;
   }
 }