GN: do not make indirect dependency to direct dependency

If a target is hard dep, there is no need to have the action targets's
recursive deps as direct dependency, because such dependency is
transitive.

This is found by pcc in gn-dev
https://groups.google.com/a/chromium.org/forum/#!topic/gn-dev/BcrSfPQE84E

With this change, generated android's toolchain.ninja size is reduced
from 262MB to 31MB. And ninja's startup time reduced from 4.9~5.1s to
2.6s.
I used args.gn same with android_n5x_swarming_rel bot.

Also this patch reduced the time of `gn gen` from 9.5~10.3s to 6.8~7.2s
on my machine.

Change-Id: I0f0214d3abe74143516b263da839e98b3987fb64
Reviewed-on: https://chromium-review.googlesource.com/1041506Reviewed-by: Brett Wilson <brettw@chromium.org>
Reviewed-by: Dirk Pranke <dpranke@chromium.org>
Commit-Queue: Takuto Ikuta <tikuta@chromium.org>
Cr-Commit-Position: refs/heads/master@{#557365}

tools/gn/ninja_action_target_writer_unittest.cc

@@ -409,3 +409,77 @@ TEST(NinjaActionTargetWriter, ForEachWithPool) {
       "build obj/foo/bar.stamp: stamp input1.out\n";
   EXPECT_EQ(expected_linux, out.str());
 }
+
+TEST(NinjaActionTargetWriter, NoTransitiveHardDeps) {
+  Err err;
+  TestWithScope setup;
+
+  setup.build_settings()->set_python_path(
+      base::FilePath(FILE_PATH_LITERAL("/usr/bin/python")));
+
+  Target dep(setup.settings(), Label(SourceDir("//foo/"), "dep"));
+  dep.set_output_type(Target::ACTION);
+  dep.visibility().SetPublic();
+  dep.SetToolchain(setup.toolchain());
+  ASSERT_TRUE(dep.OnResolved(&err));
+
+  Target foo(setup.settings(), Label(SourceDir("//foo/"), "foo"));
+  foo.set_output_type(Target::ACTION);
+  foo.visibility().SetPublic();
+  foo.sources().push_back(SourceFile("//foo/input1.txt"));
+  foo.action_values().set_script(SourceFile("//foo/script.py"));
+  foo.private_deps().push_back(LabelTargetPair(&dep));
+  foo.SetToolchain(setup.toolchain());
+  foo.action_values().outputs() =
+      SubstitutionList::MakeForTest("//out/Debug/foo.out");
+  ASSERT_TRUE(foo.OnResolved(&err));
+
+  {
+    std::ostringstream out;
+    NinjaActionTargetWriter writer(&foo, out);
+    writer.Run();
+
+    const char expected_linux[] =
+        "rule __foo_foo___rule\n"
+        // These come from the args.
+        "  command = /usr/bin/python ../../foo/script.py\n"
+        "  description = ACTION //foo:foo()\n"
+        "  restat = 1\n"
+        "\n"
+        "build foo.out: __foo_foo___rule | ../../foo/script.py"
+        " ../../foo/input1.txt obj/foo/dep.stamp\n"
+        "\n"
+        "build obj/foo/foo.stamp: stamp foo.out\n";
+    EXPECT_EQ(expected_linux, out.str());
+  }
+
+  Target bar(setup.settings(), Label(SourceDir("//bar/"), "bar"));
+  bar.set_output_type(Target::ACTION);
+  bar.sources().push_back(SourceFile("//bar/input1.txt"));
+  bar.action_values().set_script(SourceFile("//bar/script.py"));
+  bar.private_deps().push_back(LabelTargetPair(&foo));
+  bar.SetToolchain(setup.toolchain());
+  bar.action_values().outputs() =
+      SubstitutionList::MakeForTest("//out/Debug/bar.out");
+  ASSERT_TRUE(bar.OnResolved(&err)) << err.message();
+
+  {
+    std::ostringstream out;
+    NinjaActionTargetWriter writer(&bar, out);
+    writer.Run();
+
+    const char expected_linux[] =
+        "rule __bar_bar___rule\n"
+        // These come from the args.
+        "  command = /usr/bin/python ../../bar/script.py\n"
+        "  description = ACTION //bar:bar()\n"
+        "  restat = 1\n"
+        "\n"
+        // Do not have obj/foo/dep.stamp as dependency.
+        "build bar.out: __bar_bar___rule | ../../bar/script.py"
+        " ../../bar/input1.txt obj/foo/foo.stamp\n"
+        "\n"
+        "build obj/bar/bar.stamp: stamp bar.out\n";
+    EXPECT_EQ(expected_linux, out.str());
+  }
+}

tools/gn/ninja_target_writer_unittest.cc

@@ -5,6 +5,7 @@
 #include <sstream>
 
 #include "testing/gtest/include/gtest/gtest.h"
+#include "tools/gn/ninja_action_target_writer.h"
 #include "tools/gn/ninja_target_writer.h"
 #include "tools/gn/target.h"
 #include "tools/gn/test_with_scope.h"
@@ -94,6 +95,23 @@ TEST(NinjaTargetWriter, WriteInputDepsStampAndGetDep) {
     EXPECT_EQ("obj/foo/base.stamp", dep[0].value());
   }
 
+  {
+    std::ostringstream stream;
+    NinjaActionTargetWriter writer(&action, stream);
+    writer.Run();
+    EXPECT_EQ(
+        "rule __foo_action___rule\n"
+        "  command =  ../../foo/script.py\n"
+        "  description = ACTION //foo:action()\n"
+        "  restat = 1\n"
+        "\n"
+        "build: __foo_action___rule | ../../foo/script.py"
+        " ../../foo/action_source.txt ./target\n"
+        "\n"
+        "build obj/foo/action.stamp: stamp\n",
+        stream.str());
+  }
+
   // Input deps for action which should depend on the base since its a hard dep
   // that is a (indirect) dependency, as well as the the action source.
   {
@@ -104,9 +122,10 @@ TEST(NinjaTargetWriter, WriteInputDepsStampAndGetDep) {
 
     ASSERT_EQ(1u, dep.size());
     EXPECT_EQ("obj/foo/action.inputdeps.stamp", dep[0].value());
-    EXPECT_EQ("build obj/foo/action.inputdeps.stamp: stamp ../../foo/script.py "
-                  "../../foo/action_source.txt obj/foo/base.stamp\n",
-              stream.str());
+    EXPECT_EQ(
+        "build obj/foo/action.inputdeps.stamp: stamp ../../foo/script.py "
+        "../../foo/action_source.txt\n",
+        stream.str());
   }
 }
 

tools/gn/target.cc

@@ -372,7 +372,13 @@ bool Target::OnResolved(Err* err) {
 
   PullRecursiveBundleData();
   PullDependentTargetLibs();
-  PullRecursiveHardDeps();
+
+  if (!hard_dep()) {
+    // If this target is not hard_dep type, we need to pull hard dependency from
+    // dependent target, because it may not transitive for compiling tasks.
+    PullRecursiveHardDeps();
+  }
+
   if (!ResolvePrecompiledHeaders(err))
     return false;