GN: Generate phony rules for unique executables.

tools/gn/ninja_build_writer.cc

 // Copyright (c) 2013 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/ninja_build_writer.h"
 
 #include <fstream>
 #include <map>
 
 #include "base/command_line.h"
@@ skipping 173 matching lines @@
 }
 
 bool NinjaBuildWriter::WritePhonyAndAllRules(Err* err) {
   std::string all_rules;
 
   // Write phony rules for all uniquely-named targets in the default toolchain.
   // Don't do other toolchains or we'll get naming conflicts, and if the name
   // isn't unique, also skip it. The exception is for the toplevel targets
   // which we also find.
   std::map<std::string, int> small_name_count;
+  std::map<std::string, int> exe_count;
   std::vector<const Target*> toplevel_targets;
   base::hash_set<std::string> target_files;
   for (const auto& target : default_toolchain_targets_) {
     const Label& label = target->label();
     small_name_count[label.name()]++;
 
     // Look for targets with a name of the form
     //   dir = "//foo/", name = "foo"
     // i.e. where the target name matches the top level directory. We will
     // always write phony rules for these even if there is another target with
     // the same short name.
     const std::string& dir_string = label.dir().value();
     if (dir_string.size() == label.name().size() + 3 &&  // Size matches.
         dir_string[0] == '/' && dir_string[1] == '/' &&  // "//" at beginning.
         dir_string[dir_string.size() - 1] == '/' &&  // "/" at end.
         dir_string.compare(2, label.name().size(), label.name()) == 0)
       toplevel_targets.push_back(target);
+
+    // Look for executables; later we will generate phony rules for them
+    // even if there are non-executable targets with the same name.
+    if (target->output_type() == Target::EXECUTABLE)
+      exe_count[label.name()]++;
   }
 
   for (const auto& target : default_toolchain_targets_) {
     const Label& label = target->label();
     OutputFile target_file(target->dependency_output_file());
     // The output files may have leading "./" so normalize those away.
     NormalizePath(&target_file.value());
     if (!target_files.insert(target_file.value()).second) {
       *err = Err(Location(), "Duplicate rules for " + target_file.value());
       return false;
     }
 
     // Write the long name "foo/bar:baz" for the target "//foo/bar:baz".
     std::string long_name = label.GetUserVisibleName(false);
     base::TrimString(long_name, "/", &long_name);
     WritePhonyRule(target, target_file, long_name);
 
     // Write the directory name with no target name if they match
     // (e.g. "//foo/bar:bar" -> "foo/bar").
     if (FindLastDirComponent(label.dir()) == label.name()) {
       std::string medium_name =  DirectoryWithNoLastSlash(label.dir());
       base::TrimString(medium_name, "/", &medium_name);
       // That may have generated a name the same as the short name of the
       // target which we already wrote.
       if (medium_name != label.name())
         WritePhonyRule(target, target_file, medium_name);
     }
 
-    // Write short names for ones which are unique.
-    if (small_name_count[label.name()] == 1)
+    // Write short names for ones which are either completely unique or there
+    // at least only one of them in the default toolchain that is an exe.
+    if (small_name_count[label.name()] == 1 ||
+        (target->output_type() == Target::EXECUTABLE &&
+         exe_count[label.name()] == 1)) {
       WritePhonyRule(target, target_file, label.name());
+    }
 
     if (!all_rules.empty())
       all_rules.append(" $\n    ");
     all_rules.append(target_file.value());
   }
 
   // Pick up phony rules for the toplevel targets with non-unique names (which
   // would have been skipped in the above loop).
   for (const auto& toplevel_target : toplevel_targets) {
     if (small_name_count[toplevel_target->label().name()] > 1) {
@@ skipping 34 matching lines @@
   EscapeOptions ninja_escape;
   ninja_escape.mode = ESCAPE_NINJA;
 
   // Escape for special chars Ninja will handle.
   std::string escaped = EscapeString(phony_name, ninja_escape, nullptr);
 
   out_ << "build " << escaped << ": phony ";
   path_output_.WriteFile(out_, target_file);
   out_ << std::endl;
 }