[wasm] GrowMemory should use array_buffer_allocator instead of realloc.

test/mjsunit/wasm/grow-memory.js

 // Copyright 2016 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // Flags: --expose-wasm --expose-gc --stress-compaction
 
 load("test/mjsunit/wasm/wasm-constants.js");
 load("test/mjsunit/wasm/wasm-module-builder.js");
 
 var kPageSize = 0x10000;
@@ skipping 14 matching lines @@
 
 function testGrowMemoryReadWrite() {
   var builder = genGrowMemoryBuilder();
   builder.addMemory(1, 1, false);
   var module = builder.instantiate();
   var offset;
   function peek() { return module.exports.load(offset); }
   function poke(value) { return module.exports.store(offset, value); }
   function growMem(pages) { return module.exports.grow_memory(pages); }
 
-  for(offset = 0; offset <= (kPageSize - 4); offset++) {
+  for(offset = 0; offset <= (kPageSize - 4); offset+=4) {

[ahaas, 2016/09/08 12:23:34]

For this test it is actually better to write to every offset. Writing to every
offset is only bad if you first do all the writing and then do all the reading.
If you alternate reading and writing, then you can write at every offset.

[gdeepti, 2016/09/08 22:44:50]

It is better to test at every offset, but introducing overlapping stores feels
non intuitive. And also realized that bounds check should be checked for
different load sizes. Added 8/16/32 bit read write tests so that all the read
write operations and bounds check for these are tested. Not testing 64 bit in
this file because ToJS doesn't allow us to export 64 bit values. Will follow up
with grow_memory cctest suite with the next CL that fixes bounds check for 0
initial memory. This addresses the comments below as well.

     poke(20);
     assertEquals(20, peek());
   }
   for (offset = kPageSize - 3; offset < kPageSize + 4; offset++) {
     assertTraps(kTrapMemOutOfBounds, poke);
     assertTraps(kTrapMemOutOfBounds, peek);
   }
 
   assertEquals(1, growMem(3));
 
-  for (offset = kPageSize; offset <= 4*kPageSize -4; offset++) {
+  for (offset = kPageSize; offset <= 4*kPageSize -4; offset+=4) {

[ahaas, 2016/09/08 12:23:34]

same here.

     poke(20);
     assertEquals(20, peek());
   }
   for (offset = 4*kPageSize - 3; offset < 4*kPageSize + 4; offset++) {
     assertTraps(kTrapMemOutOfBounds, poke);
     assertTraps(kTrapMemOutOfBounds, peek);
   }
 
   assertEquals(4, growMem(15));
 
-  for (offset = 4*kPageSize - 3; offset <= 4*kPageSize + 4; offset++) {
+  for (offset = 4*kPageSize - 3; offset <= 4*kPageSize + 4; offset+=4) {

[ahaas, 2016/09/08 12:23:34]

same here.

     poke(20);
     assertEquals(20, peek());
   }
-  for (offset = 19*kPageSize - 10; offset <= 19*kPageSize - 4; offset++) {
+  for (offset = 19*kPageSize - 10; offset <= 19*kPageSize - 4; offset+=4) {

[ahaas, 2016/09/08 12:23:34]

same here.

     poke(20);
     assertEquals(20, peek());
   }
   for (offset = 19*kPageSize - 3; offset < 19*kPageSize + 5; offset++) {
     assertTraps(kTrapMemOutOfBounds, poke);
     assertTraps(kTrapMemOutOfBounds, peek);
   }
 }
 
 testGrowMemoryReadWrite();
 
 function testGrowMemoryZeroInitialSize() {
   var builder = genGrowMemoryBuilder();
   var module = builder.instantiate();
   var offset;
   function peek() { return module.exports.load(offset); }
   function poke(value) { return module.exports.store(offset, value); }
   function growMem(pages) { return module.exports.grow_memory(pages); }
 
   assertTraps(kTrapMemOutOfBounds, peek);
   assertTraps(kTrapMemOutOfBounds, poke);
 
   assertEquals(0, growMem(1));
 
-  for(offset = 0; offset <= kPageSize - 4; offset++) {
+  for(offset = 0; offset <= kPageSize - 4; offset+=4) {

[ahaas, 2016/09/08 12:23:34]

same here.

[gdeepti, 2016/09/08 22:44:50]

Changing this back to the way it was for now. 

     poke(20);
     assertEquals(20, peek());
   }
 
   //TODO(gdeepti): Fix tests with correct write boundaries
   //when runtime function is fixed.
   for(offset = kPageSize; offset <= kPageSize + 5; offset++) {
     assertTraps(kTrapMemOutOfBounds, peek);
   }
 }
@@ skipping 40 matching lines @@
       .exportFunc();
   var module = builder.instantiate();
   function growMem(pages) { return module.exports.grow_memory(pages); }
   function MemSize() { return module.exports.memory_size(); }
   assertEquals(65536, MemSize());
   assertEquals(1, growMem(1));
   assertEquals(131072, MemSize());
 }
 
 testGrowMemoryCurrentMemory();
+
+function testGrowMemoryPreservesDataMemOp32() {
+  var builder = genGrowMemoryBuilder();
+  builder.addMemory(1, 1, false);
+  var module = builder.instantiate();
+  var offset, val;
+  function peek() { return module.exports.load(offset); }
+  function poke(value) { return module.exports.store(offset, value); }
+  function growMem(pages) { return module.exports.grow_memory(pages); }
+
+  for(offset = 0; offset <= (kPageSize - 4); offset+=4) {
+    poke(100000 - offset);
+    assertEquals(100000 - offset, peek());
+  }
+
+  assertEquals(1, growMem(3));
+
+  for(offset = 0; offset <= (kPageSize - 4); offset+=4) {
+    assertEquals(100000 - offset, peek());
+  }
+}
+
+testGrowMemoryPreservesDataMemOp32();
+
+function testGrowMemoryPreservesDataMemOp16() {
+  var builder = genGrowMemoryBuilder();
+  builder.addMemory(1, 1, false);
+  builder.addFunction("load16", kSig_i_i)
+      .addBody([kExprGetLocal, 0, kExprI32LoadMem16U, 0, 0])
+      .exportFunc();
+  builder.addFunction("store16", kSig_i_ii)
+      .addBody([kExprGetLocal, 0, kExprGetLocal, 1, kExprI32StoreMem16, 0, 0])
+      .exportFunc();
+  var module = builder.instantiate();
+  var offset, val;
+  function peek() { return module.exports.load16(offset); }
+  function poke(value) { return module.exports.store16(offset, value); }
+  function growMem(pages) { return module.exports.grow_memory(pages); }
+
+  for(offset = 0; offset <= (kPageSize - 2); offset+=2) {
+    poke(65535 - offset);
+    assertEquals(65535 - offset, peek());
+  }
+
+  assertEquals(1, growMem(3));
+
+  for(offset = 0; offset <= (kPageSize - 2); offset+=2) {
+    assertEquals(65535 - offset, peek());
+  }
+}
+
+testGrowMemoryPreservesDataMemOp16();
+
+function testGrowMemoryPreservesDataMemOp8() {
+  var builder = genGrowMemoryBuilder();
+  builder.addMemory(1, 1, false);
+  builder.addFunction("load8", kSig_i_i)
+      .addBody([kExprGetLocal, 0, kExprI32LoadMem8U, 0, 0])
+      .exportFunc();
+  builder.addFunction("store8", kSig_i_ii)
+      .addBody([kExprGetLocal, 0, kExprGetLocal, 1, kExprI32StoreMem8, 0, 0])
+      .exportFunc();
+  var module = builder.instantiate();
+  var offset, val = 0;
+  function peek() { return module.exports.load8(offset); }
+  function poke(value) { return module.exports.store8(offset, value); }
+  function growMem(pages) { return module.exports.grow_memory(pages); }
+
+  for(offset = 0; offset <= (kPageSize - 1); offset++, val++) {
+    poke(val);
+    assertEquals(val, peek());
+    if (val == 255) val = 0;
+  }
+
+  assertEquals(1, growMem(3));
+
+  val = 0;
+
+  for(offset = 0; offset <= (kPageSize - 1); offset++, val++) {
+    assertEquals(val, peek());
+    if (val == 255) val = 0;
+  }
+}
+
+testGrowMemoryPreservesDataMemOp8();