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Commit 3cbda59f authored by Yahan Zhou's avatar Yahan Zhou
Browse files

Align DisplayEventReceiver events 

The structs are aligned differently on x86 vs x64, causing them to
parse messages wrong.

Test: CtsGraphicsTestCases android.graphics.drawable.cts.AnimatedImageDrawableTest#testLifeCycle
Bug: 149314120
Change-Id: I745ba7647ecadffed016f1694a7b4a81c5ef195c
parent 73dd99b7

libs/gui/include/gui/DisplayEventReceiver.h

+8 −3
Original line number Diff line number Diff line
@@ -57,16 +57,21 @@ public: 
    };



    struct Event {

        // We add __attribute__((aligned(8))) for nsecs_t fields because

        // we need to make sure all fields are aligned the same with x86

        // and x64 (long long has different default alignment):

        //

        // https://en.wikipedia.org/wiki/Data_structure_alignment



        struct Header {

            uint32_t type;

            PhysicalDisplayId displayId;

            PhysicalDisplayId displayId __attribute__((aligned(8)));

            nsecs_t timestamp __attribute__((aligned(8)));

        };



        struct VSync {

            uint32_t count;

            nsecs_t expectedVSyncTimestamp;

            nsecs_t expectedVSyncTimestamp __attribute__((aligned(8)));

        };



        struct Hotplug {
@@ -75,7 +80,7 @@ public: 


        struct Config {

            int32_t configId;

            nsecs_t vsyncPeriod;

            nsecs_t vsyncPeriod __attribute__((aligned(8)));

        };



        Header header;

libs/gui/tests/Android.bp

+25 −1
Original line number Diff line number Diff line
@@ -58,6 +58,30 @@ cc_test { 
    header_libs: ["libsurfaceflinger_headers"],

}



// Build the tests that need to run with both 32bit and 64bit.

cc_test {

    name: "libgui_multilib_test",

    test_suites: ["device-tests"],



    clang: true,

    cflags: [

        "-Wall",

        "-Werror",

    ],



    srcs: [

        "DisplayEventStructLayout_test.cpp",

    ],



    shared_libs: [

        "libgui",

    ],



    compile_multilib: "both",



    header_libs: ["libsurfaceflinger_headers"],

}



// Build a separate binary to $(TARGET_OUT_DATA_NATIVE_TESTS)/$(LOCAL_MODULE)

// This test has a main method, and requires a separate binary to be built.

// To add move tests like this, just add additional cc_test statements,

libs/gui/tests/DisplayEventStructLayout_test.cpp

0 → 100644
+43 −0
Original line number Diff line number Diff line 
/*

 * Copyright (C) 2020 The Android Open Source Project

 *

 * Licensed under the Apache License, Version 2.0 (the "License");

 * you may not use this file except in compliance with the License.

 * You may obtain a copy of the License at

 *

 *      http://www.apache.org/licenses/LICENSE-2.0

 *

 * Unless required by applicable law or agreed to in writing, software

 * distributed under the License is distributed on an "AS IS" BASIS,

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

 * See the License for the specific language governing permissions and

 * limitations under the License.

 */



#include <gtest/gtest.h>

#include <gui/DisplayEventReceiver.h>



namespace android::test {



#define CHECK_OFFSET(type, member, expected_offset) \

    static_assert((offsetof(type, member) == (expected_offset)), "")



TEST(DisplayEventStructLayoutTest, TestEventAlignment) {

    CHECK_OFFSET(DisplayEventReceiver::Event, vsync, 24);

    CHECK_OFFSET(DisplayEventReceiver::Event, hotplug, 24);

    CHECK_OFFSET(DisplayEventReceiver::Event, config, 24);



    CHECK_OFFSET(DisplayEventReceiver::Event::Header, type, 0);

    CHECK_OFFSET(DisplayEventReceiver::Event::Header, displayId, 8);

    CHECK_OFFSET(DisplayEventReceiver::Event::Header, timestamp, 16);



    CHECK_OFFSET(DisplayEventReceiver::Event::VSync, count, 0);

    CHECK_OFFSET(DisplayEventReceiver::Event::VSync, expectedVSyncTimestamp, 8);



    CHECK_OFFSET(DisplayEventReceiver::Event::Hotplug, connected, 0);



    CHECK_OFFSET(DisplayEventReceiver::Event::Config, configId, 0);

    CHECK_OFFSET(DisplayEventReceiver::Event::Config, vsyncPeriod, 8);

}



} // namespace android::test