[C++] Fix target specific variables with --gen_all_targets

--gen_all_targets started traversing the dependency graph from
random node. This may prevent target specific variables in
parents from being applied. With this patch, we always traverse
the graph from nodes without parents.

1 files changed, 15 insertions, 3 deletions

diff --git a/dep.cc b/dep.cc
index 3fa4c98..cb0289f 100644
--- a/dep.cc
+++ b/dep.cc
@@ -150,7 +150,7 @@ class DepBuilder {
     }
     CHECK(!first_rule_->outputs.empty());
 
-    if (targets.empty()) {
+    if (!g_flags.gen_all_targets && targets.empty()) {
       targets.push_back(first_rule_->outputs[0]);
     }
     if (g_flags.gen_all_phony_targets) {
@@ -158,8 +158,20 @@ class DepBuilder {
         targets.push_back(s);
     }
     if (g_flags.gen_all_targets) {
-      for (const auto& p : rules_)
-        targets.push_back(p.first);
+      unordered_set<Symbol> non_root_targets;
+      for (const auto& p : rules_) {
+        for (Symbol t : p.second->inputs)
+          non_root_targets.insert(t);
+        for (Symbol t : p.second->order_only_inputs)
+          non_root_targets.insert(t);
+      }
+
+      for (const auto& p : rules_) {
+        Symbol t = p.first;
+        if (!non_root_targets.count(t)) {
+          targets.push_back(p.first);
+        }
+      }
     }
 
     // TODO: LogStats?