Android WebView: make use of host multilib support.

Android.mk

 # Copyright (c) 2012 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.
 
 # This Android makefile is used to build WebView in the Android build system.
 # gyp autogenerates most of the real makefiles, which we include below.
 
 # Don't do anything if the product is using a prebuilt webviewchromium, to avoid
 # duplicate target definitions between this directory and the prebuilts.
 ifneq ($(PRODUCT_PREBUILT_WEBVIEWCHROMIUM),yes)
 
 CHROMIUM_DIR := $(call my-dir)
 
 # We default to release for the Android build system. Developers working on
 # WebView code can build with "make GYP_CONFIGURATION=Debug".
 GYP_CONFIGURATION := Release
 
 # Include the manually-written makefile that builds all the WebView java code.
 include $(CHROMIUM_DIR)/android_webview/Android.mk
 
 # If the gyp-generated makefile exists for the current host OS and primary
 # target architecture, we need to include it. If it doesn't exist then just do
 # nothing, since we may not have finished bringing up this architecture yet.
+ifneq (,$(wildcard $(CHROMIUM_DIR)/GypAndroid.$(HOST_OS)-$(TARGET_ARCH).mk))
+
 # We set GYP_VAR_PREFIX to the empty string to indicate that we are building for
 # the primary target architecture.
-ifneq (,$(wildcard $(CHROMIUM_DIR)/GypAndroid.$(HOST_OS)-$(TARGET_ARCH).mk))
 GYP_VAR_PREFIX :=
+
+# If the host is declared as being 64-bit, set the host multilib variables
+# appropriately to ensure that the host targets are the same "bitness" as the
+# primary target, which is required by V8.
+ifeq ($(HOST_IS_64_BIT),true)
+ifeq ($(TARGET_IS_64_BIT),true)
+GYP_HOST_VAR_PREFIX :=
+GYP_HOST_MULTILIB := 64
+else  # Target is 32-bit.
+GYP_HOST_VAR_PREFIX := $(HOST_2ND_ARCH_VAR_PREFIX)
+GYP_HOST_MULTILIB := 32
+endif
+endif
+
 include $(CHROMIUM_DIR)/GypAndroid.$(HOST_OS)-$(TARGET_ARCH).mk
-endif
+
+endif  # End primary architecture handling.
 
 # Do the same check for the secondary architecture; if this doesn't exist then
 # the current target platform probably doesn't have a secondary architecture and
 # we can just do nothing.
+ifneq (,$(wildcard $(CHROMIUM_DIR)/GypAndroid.$(HOST_OS)-$(TARGET_2ND_ARCH).mk))
+
 # We set GYP_VAR_PREFIX to $(TARGET_2ND_ARCH_VAR_PREFIX) to indicate that we are
 # building for the secondary target architecture.
-ifneq (,$(wildcard $(CHROMIUM_DIR)/GypAndroid.$(HOST_OS)-$(TARGET_2ND_ARCH).mk))
 GYP_VAR_PREFIX := $(TARGET_2ND_ARCH_VAR_PREFIX)
-include $(CHROMIUM_DIR)/GypAndroid.$(HOST_OS)-$(TARGET_2ND_ARCH).mk
+
+# If the host is declared as being 64-bit, set the host multilib variables
+# appropriately to ensure that the host targets are the same "bitness" as the
+# secondary target, which is required by V8.
+ifeq ($(HOST_IS_64_BIT),true)
+ifeq ($(2ND_TARGET_IS_64_BIT),true)

[Ying Wang, 2014/05/30 21:42:29]

This won't happen.

+GYP_HOST_VAR_PREFIX :=
+GYP_HOST_MULTILIB := 64

[Ying Wang, 2014/05/30 21:42:29]

Even if that happens, shouldn't it be set to 32? because you are building for
the TARGET_2ND_ARCH, which is 32-bit.

[Ying Wang, 2014/05/30 21:49:57]

Sorry, I mistook the conditional as ifeq ($(2ND_HOST_IS_64_BIT),true)...
This makes sense to me now, though it's unlikely we'll have target 2nd arch as
64-bit, I think.

[Torne, 2014/06/02 10:15:49]

Even if it's unlikely it doesn't hurt to have the conditional here just to make
it clear, I don't think.

[Ying Wang, 2014/06/02 17:02:54]

Sounds good.
Thanks for the change!

+else  # Second target is 32-bit.
+GYP_HOST_VAR_PREFIX := $(HOST_2ND_ARCH_VAR_PREFIX)
+GYP_HOST_MULTILIB := 32
+endif
 endif
 
+include $(CHROMIUM_DIR)/GypAndroid.$(HOST_OS)-$(TARGET_2ND_ARCH).mk
+
+endif  # End secondary architecture handling.
+
 endif