Merge "x86_64: Align uint64_t/int64_t structure member to 8 bytes"

include/input/Input.h

@@ -170,7 +170,7 @@ struct PointerCoords {
     enum { MAX_AXES = 14 }; // 14 so that sizeof(PointerCoords) == 64
 
     // Bitfield of axes that are present in this structure.
-    uint64_t bits;
+    uint64_t bits __attribute__((aligned(8)));
 
     // Values of axes that are stored in this structure packed in order by axis id
     // for each axis that is present in the structure according to 'bits'.

include/input/InputTransport.h

@@ -39,6 +39,9 @@ namespace android {
 
 /*
  * Intermediate representation used to send input events and related signals.
+ *
+ * Note that this structure is used for IPCs so its layout must be identical
+ * on 64 and 32 bit processes. This is tested in StructLayout_test.cpp.
  */
 struct InputMessage {
     enum {
@@ -49,13 +52,17 @@ struct InputMessage {
 
     struct Header {
         uint32_t type;
-        uint32_t padding; // 8 byte alignment for the body that follows
+        // We don't need this field in order to align the body below but we
+        // leave it here because InputMessage::size() and other functions
+        // compute the size of this structure as sizeof(Header) + sizeof(Body).
+        uint32_t padding;
     } header;
 
+    // Body *must* be 8 byte aligned.
     union Body {
         struct Key {
             uint32_t seq;
-            nsecs_t eventTime;
+            nsecs_t eventTime __attribute__((aligned(8)));
             int32_t deviceId;
             int32_t source;
             int32_t action;
@@ -64,7 +71,7 @@ struct InputMessage {
             int32_t scanCode;
             int32_t metaState;
             int32_t repeatCount;
-            nsecs_t downTime;
+            nsecs_t downTime __attribute__((aligned(8)));
 
             inline size_t size() const {
                 return sizeof(Key);
@@ -73,7 +80,7 @@ struct InputMessage {
 
         struct Motion {
             uint32_t seq;
-            nsecs_t eventTime;
+            nsecs_t eventTime __attribute__((aligned(8)));
             int32_t deviceId;
             int32_t source;
             int32_t action;
@@ -81,13 +88,14 @@ struct InputMessage {
             int32_t metaState;
             int32_t buttonState;
             int32_t edgeFlags;
-            nsecs_t downTime;
+            nsecs_t downTime __attribute__((aligned(8)));
             float xOffset;
             float yOffset;
             float xPrecision;
             float yPrecision;
             uint32_t pointerCount;
-            struct Pointer {
+            // Note that PointerCoords requires 8 byte alignment.
+            struct Pointer{
                 PointerProperties properties;
                 PointerCoords coords;
             } pointers[MAX_POINTERS];
@@ -112,7 +120,7 @@ struct InputMessage {
                 return sizeof(Finished);
             }
         } finished;
-    } body;
+    } __attribute__((aligned(8))) body;
 
     bool isValid(size_t actualSize) const;
     size_t size() const;

libs/input/tests/Android.mk

@@ -29,5 +29,16 @@ $(foreach file,$(test_src_files), \
     $(eval include $(BUILD_NATIVE_TEST)) \
 )
 
+# NOTE: This is a compile time test, and does not need to be
+# run. All assertions are static_asserts and will fail during
+# buildtime if something's wrong.
+include $(CLEAR_VARS)
+LOCAL_SRC_FILES := StructLayout_test.cpp
+LOCAL_MODULE := StructLayout_test
+LOCAL_CFLAGS := -std=c++11 -O0
+LOCAL_MULTILIB := both
+include $(BUILD_STATIC_LIBRARY)
+
+
 # Build the manual test programs.
 include $(call all-makefiles-under, $(LOCAL_PATH))

libs/input/tests/StructLayout_test.cpp

@@ -0,0 +1,67 @@
+/*
+ * Copyright (C) 2014 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 <input/InputTransport.h>
+#include <input/Input.h>
+
+namespace android {
+
+#define CHECK_OFFSET(type, member, expected_offset) \
+  static_assert((offsetof(type, member) == expected_offset), "")
+
+struct Foo {
+  uint32_t dummy;
+  PointerCoords coords;
+};
+
+void TestPointerCoordsAlignment() {
+  CHECK_OFFSET(Foo, coords, 8);
+}
+
+void TestInputMessageAlignment() {
+  CHECK_OFFSET(InputMessage, body, 8);
+
+  CHECK_OFFSET(InputMessage::Body::Key, seq, 0);
+  CHECK_OFFSET(InputMessage::Body::Key, eventTime, 8);
+  CHECK_OFFSET(InputMessage::Body::Key, deviceId, 16);
+  CHECK_OFFSET(InputMessage::Body::Key, source, 20);
+  CHECK_OFFSET(InputMessage::Body::Key, action, 24);
+  CHECK_OFFSET(InputMessage::Body::Key, flags, 28);
+  CHECK_OFFSET(InputMessage::Body::Key, keyCode, 32);
+  CHECK_OFFSET(InputMessage::Body::Key, scanCode, 36);
+  CHECK_OFFSET(InputMessage::Body::Key, metaState, 40);
+  CHECK_OFFSET(InputMessage::Body::Key, repeatCount, 44);
+  CHECK_OFFSET(InputMessage::Body::Key, downTime, 48);
+
+  CHECK_OFFSET(InputMessage::Body::Motion, seq, 0);
+  CHECK_OFFSET(InputMessage::Body::Motion, eventTime, 8);
+  CHECK_OFFSET(InputMessage::Body::Motion, deviceId, 16);
+  CHECK_OFFSET(InputMessage::Body::Motion, source, 20);
+  CHECK_OFFSET(InputMessage::Body::Motion, action, 24);
+  CHECK_OFFSET(InputMessage::Body::Motion, flags, 28);
+  CHECK_OFFSET(InputMessage::Body::Motion, metaState, 32);
+  CHECK_OFFSET(InputMessage::Body::Motion, buttonState, 36);
+  CHECK_OFFSET(InputMessage::Body::Motion, edgeFlags, 40);
+  CHECK_OFFSET(InputMessage::Body::Motion, downTime, 48);
+  CHECK_OFFSET(InputMessage::Body::Motion, xOffset, 56);
+  CHECK_OFFSET(InputMessage::Body::Motion, yOffset, 60);
+  CHECK_OFFSET(InputMessage::Body::Motion, xPrecision, 64);
+  CHECK_OFFSET(InputMessage::Body::Motion, yPrecision, 68);
+  CHECK_OFFSET(InputMessage::Body::Motion, pointerCount, 72);
+  CHECK_OFFSET(InputMessage::Body::Motion, pointers, 80);
+}
+
+} // namespace android