<tools/gyp> Allow letting qmake do the link step

This adds a let_qmake_do_the_linking target variable to tell ninja
not to link but rather dump the linking information from gyp in a
file that we'll parse with qmake.

Reviewed-by: Zoltan Arvai <[email protected]>
Reviewed-by: Andras Becsi <[email protected]>
Change-Id: I753888776679e449d7a64b6bf5b47e7a60dfa827
Reviewed-by: Zeno Albisser <[email protected]>

Author: jturcotte

chromium/tools/gyp/pylib/gyp/generator/ninja.py

@@ -1101,6 +1101,49 @@ def WriteLinkForArch(self, ninja_file, spec, config_name, config,
       else:
         command = command + '_notoc'
 
+      if config.get('let_qmake_do_the_linking', 0):
+        def toAbsPaths(paths):
+          return [os.path.relpath(path, self.toplevel_build) if os.path.isabs(path) else path
+                  for path in paths]
+        def qmakeLiteral(s):
+          return s.replace('"', '\\"')
+
+        # Generate this file for all solink targets, this assumes that
+        # a .pro file will pick up this pri file and do the rest of the work.
+        pri_file = open(os.path.join(self.toplevel_build, self.name + "_linking.pri"), 'w')
+
+        if self.flavor == 'win':
+          # qmake will take care of the manifest
+          ldflags = filter(lambda x: not x.lower().startswith('/manifest'), ldflags)
+
+        # Replace "$!PRODUCT_DIR" with "$$PWD" in link flags (which might contain some -L directives).
+        prefixed_lflags = [self.ExpandSpecial(f, '$$PWD') for f in ldflags]
+        prefixed_library_dirs = ['-L' + self.ExpandSpecial(f, '$$PWD') for f in config.get('library_dirs', [])]
+        prefixed_libraries = gyp.common.uniquer([self.ExpandSpecial(f, '$$PWD') for f in spec.get('libraries', [])])
+        if self.flavor == 'mac':
+          prefixed_libraries = self.xcode_settings.AdjustLibraries(prefixed_libraries)
+        elif self.flavor == 'win':
+          prefixed_libraries = self.msvs_settings.AdjustLibraries(prefixed_libraries)
+
+        # Make sure that we have relative paths to our out/(Release|Debug), where we generate our .pri file, and then prepend $$PWD to them.
+        prefixed_object_and_archives = ['$$PWD/' + o for o in toAbsPaths(link_deps)]
+
+        pri_file.write("QMAKE_LFLAGS += %s\n" % qmakeLiteral(' '.join(prefixed_lflags)))
+        # Follow the logic of the solink rule.
+        if self.flavor != 'mac' and self.flavor != 'win':
+          pri_file.write("LIBS_PRIVATE += -Wl,--whole-archive %s -Wl,--no-whole-archive\n" % qmakeLiteral(' '.join(prefixed_object_and_archives)))
+        else:
+          pri_file.write("LIBS_PRIVATE += %s\n" % qmakeLiteral(' '.join(prefixed_object_and_archives)))
+        # External libs have to come after objects/archives, the linker resolve them in order.
+        pri_file.write("LIBS_PRIVATE += %s\n" % qmakeLiteral(' '.join(prefixed_library_dirs + prefixed_libraries)))
+        # Make sure that if ninja modifies one of the inputs, qmake/make will link again.
+        pri_file.write("POST_TARGETDEPS += %s\n" % qmakeLiteral(' '.join(prefixed_object_and_archives)))
+        pri_file.close()
+
+        # In this mode we prevent letting ninja link at all.
+        command = 'phony'
+        command_suffix = ''
+
     if len(solibs):
       extra_bindings.append(('solibs', gyp.common.EncodePOSIXShellList(solibs)))