ARM64: Restore FP registers in read barrier thunk.

bug: 62612946
Test: 658-fp-read-barrier
Test: run-libcore-tests.sh

(cherry picked from commit 7015e76436ff9eb738c9c6070c8fff8e98b3852e)

Change-Id: Id0bc55c21829429cd17a77e4c503971249c107f5
diff --git a/runtime/arch/arm64/quick_entrypoints_arm64.S b/runtime/arch/arm64/quick_entrypoints_arm64.S
index 7220644..820ba0e 100644
--- a/runtime/arch/arm64/quick_entrypoints_arm64.S
+++ b/runtime/arch/arm64/quick_entrypoints_arm64.S
@@ -2611,19 +2611,19 @@
     RESTORE_TWO_REGS x14, x15, 112
     RESTORE_TWO_REGS x18, x19, 128    // Skip x16, x17, i.e. IP0, IP1.
     RESTORE_REG      xLR,      144    // Restore return address.
-    // Save all potentially live caller-save floating-point registers.
-    stp   d0, d1,   [sp, #160]
-    stp   d2, d3,   [sp, #176]
-    stp   d4, d5,   [sp, #192]
-    stp   d6, d7,   [sp, #208]
-    stp   d16, d17, [sp, #224]
-    stp   d18, d19, [sp, #240]
-    stp   d20, d21, [sp, #256]
-    stp   d22, d23, [sp, #272]
-    stp   d24, d25, [sp, #288]
-    stp   d26, d27, [sp, #304]
-    stp   d28, d29, [sp, #320]
-    stp   d30, d31, [sp, #336]
+    // Restore caller-save floating-point registers.
+    ldp   d0, d1,   [sp, #160]
+    ldp   d2, d3,   [sp, #176]
+    ldp   d4, d5,   [sp, #192]
+    ldp   d6, d7,   [sp, #208]
+    ldp   d16, d17, [sp, #224]
+    ldp   d18, d19, [sp, #240]
+    ldp   d20, d21, [sp, #256]
+    ldp   d22, d23, [sp, #272]
+    ldp   d24, d25, [sp, #288]
+    ldp   d26, d27, [sp, #304]
+    ldp   d28, d29, [sp, #320]
+    ldp   d30, d31, [sp, #336]
 
     ldr   x0, [lr, #\ldr_offset]      // Load the instruction.
     adr   xIP1, .Lmark_introspection_return_switch
diff --git a/test/658-fp-read-barrier/expected.txt b/test/658-fp-read-barrier/expected.txt
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/test/658-fp-read-barrier/expected.txt
diff --git a/test/658-fp-read-barrier/info.txt b/test/658-fp-read-barrier/info.txt
new file mode 100644
index 0000000..26ecb60
--- /dev/null
+++ b/test/658-fp-read-barrier/info.txt
@@ -0,0 +1,2 @@
+Regression test for the read barrier implementation in ARM64,
+which used to not restore floating point registers.
diff --git a/test/658-fp-read-barrier/src/Main.java b/test/658-fp-read-barrier/src/Main.java
new file mode 100644
index 0000000..c2bd10d
--- /dev/null
+++ b/test/658-fp-read-barrier/src/Main.java
@@ -0,0 +1,136 @@
+/*
+ * Copyright (C) 2017 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.
+ */
+
+public class Main {
+  static volatile boolean done = false;
+
+  public static void main(String[] args) {
+    // Run a thread for 30 seconds, allocating memory and triggering garbage
+    // collection.
+    // Time is limited to 30 seconds to not make this test too long. The test used
+    // to trigger the failure around 1 every 10 runs.
+    Thread t = new Thread() {
+      public void run() {
+        long time = System.currentTimeMillis();
+        while (System.currentTimeMillis() - time < 30000) {
+          for (int j = 0; j < 10000; j++) {
+            o = new Object[1000];
+          }
+          Runtime.getRuntime().gc();
+          Thread.yield();
+        }
+        Main.done = true;
+      }
+      Object o;
+    };
+    // Make the thread a daemon to quit early in case of an
+    // exception throw below.
+    t.setDaemon(true);
+    t.start();
+
+    // Run 'foo' as long as the test runs.
+    while (!done) {
+      double res = foo(staticMain);
+      if (res != 529.0) {
+        throw new Error("Unexpected result " + res);
+      }
+    }
+  }
+
+  public static double foo(Main main) {
+    // Use up all D registers on arm64.
+    double d1 = main.field1;
+    double d2 = main.field2;
+    double d3 = main.field3;
+    double d4 = main.field4;
+    double d5 = main.field5;
+    double d6 = main.field6;
+    double d7 = main.field7;
+    double d8 = main.field8;
+    double d9 = main.field9;
+    double d10 = main.field10;
+    double d11 = main.field11;
+    double d12 = main.field12;
+    double d13 = main.field13;
+    double d14 = main.field14;
+    double d15 = main.field15;
+    double d16 = main.field16;
+    double d17 = main.field17;
+    double d18 = main.field18;
+    double d19 = main.field19;
+    double d20 = main.field20;
+    double d21 = main.field21;
+    double d22 = main.field22;
+    double d23 = main.field23;
+    double d24 = main.field24;
+    double d25 = main.field25;
+    double d26 = main.field26;
+    double d27 = main.field27;
+    double d28 = main.field28;
+    double d29 = main.field29;
+    double d30 = main.field30;
+    double d31 = main.field31;
+    double d32 = main.field32;
+
+    // Trigger a read barrier. This used to make the test trip on ARM64 as
+    // the read barrier stub used to not restore the D registers.
+    double p = main.objectField.field1;
+
+    return p + d1 + d2 + d3 + d4 + d5 + d6 + d7 + d8 + d9 + d10 + d11 + d12 + d13 + d14 + d15 + d16 + d17 + d18 + d19 + d20 + d21 + d22 + d23 + d24 + d25 + d26 + d27 + d28 + d29 + d30 + d31 + d32;
+  }
+
+  // Initialize objects here and not in 'main' to avoid having
+  // these objects in roots.
+  public static Main staticMain = new Main();
+  static {
+    staticMain.objectField = new Main();
+  }
+
+  public Main objectField;
+
+  public double field1 = 1.0;
+  public double field2 = 2.0;
+  public double field3 = 3.0;
+  public double field4 = 4.0;
+  public double field5 = 5.0;
+  public double field6 = 6.0;
+  public double field7 = 7.0;
+  public double field8 = 8.0;
+  public double field9 = 9.0;
+  public double field10 = 10.0;
+  public double field11 = 11.0;
+  public double field12 = 12.0;
+  public double field13 = 13.0;
+  public double field14 = 14.0;
+  public double field15 = 15.0;
+  public double field16 = 16.0;
+  public double field17 = 17.0;
+  public double field18 = 18.0;
+  public double field19 = 19.0;
+  public double field20 = 20.0;
+  public double field21 = 21.0;
+  public double field22 = 22.0;
+  public double field23 = 23.0;
+  public double field24 = 24.0;
+  public double field25 = 25.0;
+  public double field26 = 26.0;
+  public double field27 = 27.0;
+  public double field28 = 28.0;
+  public double field29 = 29.0;
+  public double field30 = 30.0;
+  public double field31 = 31.0;
+  public double field32 = 32.0;
+}