add "special=gcc" attribute, use to load depslog

2 files changed, 44 insertions, 11 deletions

diff --git a/src/graph.cc b/src/graph.cc
index 43f4304..2f86785 100644
--- a/src/graph.cc
+++ b/src/graph.cc
@@ -53,22 +53,19 @@ bool Rule::IsReservedBinding(const string& var) {
       var == "pool" ||
       var == "restat" ||
       var == "rspfile" ||
-      var == "rspfile_content";
+      var == "rspfile_content" ||
+      var == "special";
 }
 
 bool DependencyScan::RecomputeDirty(Edge* edge, string* err) {
   bool dirty = false;
   edge->outputs_ready_ = true;
 
-  string depfile = edge->GetBinding("depfile");
-  if (!depfile.empty()) {
-    if (!dep_loader_.LoadDepFile(edge, depfile, err)) {
-      if (!err->empty())
-        return false;
-      EXPLAIN("Edge targets are dirty because depfile '%s' is missing",
-              depfile.c_str());
-      dirty = true;
-    }
+  if (!dep_loader_.LoadDeps(edge, err)) {
+    if (!err->empty())
+      return false;
+    // Failed to load dependency info: rebuild to regenerate it.
+    dirty = true;
   }
 
   // Visit all inputs; we're dirty if any of the inputs are dirty.
@@ -325,6 +322,33 @@ void Node::Dump(const char* prefix) const {
   }
 }
 
+bool ImplicitDepLoader::LoadDeps(Edge* edge, string* err) {
+  string special = edge->GetBinding("special");
+  if (!special.empty() && special == "gcc") {
+    if (!LoadDepsFromLog(edge, err)) {
+      if (!err->empty())
+        return false;
+      EXPLAIN("deps for %s are missing", edge->outputs_[0]->path().c_str());
+      return false;
+    }
+    return true;
+  }
+
+  string depfile = edge->GetBinding("depfile");
+  if (!depfile.empty()) {
+    if (!LoadDepFile(edge, depfile, err)) {
+      if (!err->empty())
+        return false;
+      EXPLAIN("depfile '%s' is missing", depfile.c_str());
+      return false;
+    }
+    return true;
+  }
+
+  // No deps to load.
+  return true;
+}
+
 bool ImplicitDepLoader::LoadDepFile(Edge* edge, const string& path,
                                     string* err) {
   METRIC_RECORD("depfile load");
diff --git a/src/graph.h b/src/graph.h
index d943702..a7b60db 100644
--- a/src/graph.h
+++ b/src/graph.h
@@ -192,10 +192,19 @@ struct ImplicitDepLoader {
                     DiskInterface* disk_interface)
       : state_(state), disk_interface_(disk_interface), deps_log_(deps_log) {}
 
+  /// Load implicit dependencies for \a edge.
+  /// @return false on error (without filling \a err if info is just missing).
+  bool LoadDeps(Edge* edge, string* err);
+
+ private:
+  /// Load implicit dependencies for \a edge from a depfile attribute.
+  /// @return false on error (without filling \a err if info is just missing).
   bool LoadDepFile(Edge* edge, const string& path, string* err);
+
+  /// Load implicit dependencies for \a edge from the DepsLog.
+  /// @return false on error (without filling \a err if info is just missing).
   bool LoadDepsFromLog(Edge* edge, string* err);
 
- private:
   /// Preallocate \a count spaces in the input array on \a edge, returning
   /// an iterator pointing at the first new space.
   vector<Node*>::iterator PreallocateSpace(Edge* edge, int count);