From c69fba293481af4a0963ec656c3aa9b959d44e01 Mon Sep 17 00:00:00 2001
From: Vladimir Marko <vmarko@google.com>
Date: Tue, 6 Sep 2016 16:49:15 +0100
Subject: [PATCH] Optimizing: Fix handling empty fill-array-data.

Test: m test-art-host-run-test-412-new-array
Bug: 31300081
Change-Id: Id0512fc95a96c37de2ceab481666688435fa30f6
---
 compiler/optimizing/instruction_builder.cc     | 10 ++++--
 test/412-new-array/smali/fill_array_data.smali | 12 +++++++
 test/412-new-array/src/Main.java               | 46 ++++++++++++++++++++++----
 3 files changed, 59 insertions(+), 9 deletions(-)

diff --git a/compiler/optimizing/instruction_builder.cc b/compiler/optimizing/instruction_builder.cc
index 453068b56..32dcc2814 100644
--- a/compiler/optimizing/instruction_builder.cc
+++ b/compiler/optimizing/instruction_builder.cc
@@ -1545,8 +1545,6 @@ void HInstructionBuilder::BuildFillArrayData(HInstruction* object,
 
 void HInstructionBuilder::BuildFillArrayData(const Instruction& instruction, uint32_t dex_pc) {
   HInstruction* array = LoadNullCheckedLocal(instruction.VRegA_31t(), dex_pc);
-  HInstruction* length = new (arena_) HArrayLength(array, dex_pc);
-  AppendInstruction(length);
 
   int32_t payload_offset = instruction.VRegB_31t() + dex_pc;
   const Instruction::ArrayDataPayload* payload =
@@ -1554,6 +1552,14 @@ void HInstructionBuilder::BuildFillArrayData(const Instruction& instruction, uin
   const uint8_t* data = payload->data;
   uint32_t element_count = payload->element_count;
 
+  if (element_count == 0u) {
+    // For empty payload we emit only the null check above.
+    return;
+  }
+
+  HInstruction* length = new (arena_) HArrayLength(array, dex_pc);
+  AppendInstruction(length);
+
   // Implementation of this DEX instruction seems to be that the bounds check is
   // done before doing any stores.
   HInstruction* last_index = graph_->GetIntConstant(payload->element_count - 1, dex_pc);
diff --git a/test/412-new-array/smali/fill_array_data.smali b/test/412-new-array/smali/fill_array_data.smali
index 2b24e56ce..f16308443 100644
--- a/test/412-new-array/smali/fill_array_data.smali
+++ b/test/412-new-array/smali/fill_array_data.smali
@@ -2,6 +2,18 @@
 
 .super Ljava/lang/Object;
 
+.method public static emptyIntArray([I)V
+   .registers 1
+
+   fill-array-data v0, :ArrayData
+   return-void
+
+:ArrayData
+    .array-data 4
+    .end array-data
+
+.end method
+
 .method public static intArray([I)V
    .registers 1
 
diff --git a/test/412-new-array/src/Main.java b/test/412-new-array/src/Main.java
index d95d2c52f..fb348ba9c 100644
--- a/test/412-new-array/src/Main.java
+++ b/test/412-new-array/src/Main.java
@@ -220,6 +220,38 @@ public class Main extends TestCase {
   public static void testSmaliFillArrayData() throws Exception {
     Class<?> c = Class.forName("FillArrayData");
     {
+      Method m = c.getMethod("emptyIntArray", int[].class);
+      int[] array = new int[0];
+      Object[] args = { array };
+      m.invoke(null, args);
+      assertEquals(0, array.length);
+
+      array = new int[2];
+      args[0] = array;
+      m.invoke(null, args);
+      // Test that nothing has been written to the array.
+      assertEquals(0, array[0]);
+      assertEquals(0, array[1]);
+
+      array = new int[] { 42, -42 };
+      args[0] = array;
+      m.invoke(null, args);
+      // Test that nothing has been written to the array.
+      assertEquals(42, array[0]);
+      assertEquals(-42, array[1]);
+
+      Throwable exception = null;
+      args[0] = null;
+      try {
+        m.invoke(null, args);
+      } catch (InvocationTargetException e) {
+        exception = e.getCause();
+        assertTrue(exception instanceof NullPointerException);
+      }
+      assertNotNull(exception);
+    }
+
+    {
       Method m = c.getMethod("intArray", int[].class);
       int[] array = new int[7];
       Object[] args = { array };
@@ -235,7 +267,7 @@ public class Main extends TestCase {
 
       array = new int[2];
       args[0] = array;
-      Throwable exception  = null;
+      Throwable exception = null;
       try {
         m.invoke(null, args);
       } catch (InvocationTargetException e) {
@@ -274,7 +306,7 @@ public class Main extends TestCase {
 
       array = new int[2];
       args[0] = array;
-      Throwable exception  = null;
+      Throwable exception = null;
       try {
         m.invoke(null, args);
       } catch (InvocationTargetException e) {
@@ -313,7 +345,7 @@ public class Main extends TestCase {
 
       array = new short[2];
       args[0] = array;
-      Throwable exception  = null;
+      Throwable exception = null;
       try {
         m.invoke(null, args);
       } catch (InvocationTargetException e) {
@@ -352,7 +384,7 @@ public class Main extends TestCase {
 
       array = new long[2];
       args[0] = array;
-      Throwable exception  = null;
+      Throwable exception = null;
       try {
         m.invoke(null, args);
       } catch (InvocationTargetException e) {
@@ -391,7 +423,7 @@ public class Main extends TestCase {
 
       array = new char[2];
       args[0] = array;
-      Throwable exception  = null;
+      Throwable exception = null;
       try {
         m.invoke(null, args);
       } catch (InvocationTargetException e) {
@@ -430,7 +462,7 @@ public class Main extends TestCase {
 
       array = new byte[2];
       args[0] = array;
-      Throwable exception  = null;
+      Throwable exception = null;
       try {
         m.invoke(null, args);
       } catch (InvocationTargetException e) {
@@ -467,7 +499,7 @@ public class Main extends TestCase {
 
       array = new boolean[2];
       args[0] = array;
-      Throwable exception  = null;
+      Throwable exception = null;
       try {
         m.invoke(null, args);
       } catch (InvocationTargetException e) {
-- 
2.11.0