win: Add NoImportLibrary flag for ninja generator

This adds a flag that tells ninja not to expect an import library
to be generated. This is only needed very rarely in the case of
DLLs that have no exported symbols.

There is no corresponding functionality in the msvs generator, so
the test and functionality are ninja generator-only.

R=grt@chromium.org
BUG=gyp:397, chromium:451499

Review URL: https://codereview.chromium.org/890773004

git-svn-id: http://gyp.googlecode.com/svn/trunk@2030 78cadc50-ecff-11dd-a971-7dbc132099af

pylib/gyp/generator/ninja.py

@@ -1217,7 +1217,8 @@ def WriteLinkForArch(self, ninja_file, spec, config_name, config,
             gyp.common.EncodePOSIXShellArgument(link_file_list)))
       if self.flavor == 'win':
         extra_bindings.append(('binary', output))
-        if '/NOENTRY' not in ldflags:
+        if ('/NOENTRY' not in ldflags and
+            not self.msvs_settings.GetNoImportLibrary(config_name)):
           self.target.import_lib = output + '.lib'
           extra_bindings.append(('implibflag',
                                  '/IMPLIB:%s' % self.target.import_lib))

pylib/gyp/msvs_emulation.py

@@ -407,6 +407,13 @@ def GetPDBName(self, config, expand_special, default):
     else:
       return None
 
+  def GetNoImportLibrary(self, config):
+    """If NoImportLibrary: true, ninja will not expect the output to include
+    an import library."""
+    config = self._TargetConfig(config)
+    noimplib = self._Setting(('NoImportLibrary',), config)
+    return noimplib == 'true'
+
   def GetAsmflags(self, config):
     """Returns the flags that need to be added to ml invocations."""
     config = self._TargetConfig(config)

test/win/gyptest-link-noimportlib.py

@@ -0,0 +1,30 @@
+#!/usr/bin/env python
+
+# Copyright (c) 2015 Google Inc. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+"""
+Make sure that the (custom) NoImportLibrary flag is handled correctly.
+"""
+
+import TestGyp
+
+import os
+import sys
+
+if sys.platform == 'win32':
+  test = TestGyp.TestGyp(formats=['ninja'])
+
+  CHDIR = 'importlib'
+  test.run_gyp('noimplib.gyp', chdir=CHDIR)
+  test.build('noimplib.gyp', test.ALL, chdir=CHDIR)
+
+  # The target has an entry point, but no exports. Ordinarily, ninja expects
+  # all DLLs to export some symbols (with the exception of /NOENTRY resource-
+  # only DLLs). When the NoImportLibrary flag is set, this is suppressed. If
+  # this is not working correctly, the expected .lib will never be generated
+  # but will be expected, so the build will not be up to date.
+  test.up_to_date('noimplib.gyp', test.ALL, chdir=CHDIR)
+
+  test.pass_test()

test/win/importlib/dll_no_exports.cc

@@ -0,0 +1,9 @@
+// Copyright (c) 2015 Google Inc. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include <windows.h>
+
+BOOL APIENTRY DllMain(HMODULE module, DWORD reason, LPVOID reserved) {
+  return TRUE;
+}

test/win/importlib/noimplib.gyp

@@ -0,0 +1,16 @@
+# Copyright (c) 2015 Google Inc. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+{
+ 'targets': [
+    {
+      'target_name': 'no_import_library',
+      'type': 'loadable_module',
+      'msvs_settings': {
+        'NoImportLibrary': 'true',
+      },
+      'sources': ['dll_no_exports.cc'],
+    },
+  ]
+}