Implement Wasm GrowMemory opcode as a wasm runtime call

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");
+
+function genGrowMemoryBuilder() {
+  var builder = new WasmModuleBuilder();
+  builder.addFunction("grow_memory", kSig_i_i)
+      .addBody([kExprGetLocal, 0, kExprGrowMemory])
+      .exportFunc();
+  builder.addFunction("load", kSig_i_i)
+      .addBody([kExprGetLocal, 0, kExprI32LoadMem, 0, 0])
+      .exportFunc();
+  builder.addFunction("store", kSig_i_ii)
+      .addBody([kExprGetLocal, 0, kExprGetLocal, 1, kExprI32StoreMem, 0, 0])
+      .exportFunc();
+  return builder;
+}
+
+function testGrowMemoryReadWrite() {
+  var builder = genGrowMemoryBuilder();
+  builder.addMemory(1, 1, false);
+  var module = builder.instantiate();
+  var offset;
+  function peek() { return module.exports.load(offset); }

[ahaas, 2016/06/24 11:10:15]

why don't you pass in offset as a parameter?

[gdeepti, 2016/06/25 00:28:42]

Because the assertTraps function in wasm-constants.js does not take function
arguments, I figured this might be cleaner than taking in arguments in
assertTraps, would you prefer it the other way around?   

+  function poke(value) { return module.exports.store(offset, value); }
+  function growMem(pages) { return module.exports.grow_memory(pages); }
+
+  for(offset = 0; offset < 65533; offset++) {

[ahaas, 2016/06/24 11:10:15]

could you use a named constant here instead of 65533?

[gdeepti, 2016/06/25 00:28:42]

Done.

+    poke(20);
+    assertEquals(peek(), 20);
+  }
+  for (offset = 65534; offset < 66538; offset++) {

[ahaas, 2016/06/24 11:10:15]

same here

[gdeepti, 2016/06/25 00:28:41]

Done.

+    assertTraps(kTrapMemOutOfBounds, poke);
+    assertTraps(kTrapMemOutOfBounds, peek);
+  }
+
+  try {
+    assertEquals(growMem(3), 1);
+  } catch (e) {
+    assertEquals("object", typeof e);
+    assertEquals(e.message, "failed to allocate memory");
+    return;
+  }
+
+  for (offset = 65534; offset < 262141; offset++) {

[ahaas, 2016/06/24 11:10:15]

same here

[gdeepti, 2016/06/25 00:28:42]

Done.

+    poke(20);
+    assertEquals(peek(), 20);
+  }
+  for (offset = 262142; offset < 262145; offset++) {

[ahaas, 2016/06/24 11:10:15]

same here

[gdeepti, 2016/06/25 00:28:41]

Done.

+    assertTraps(kTrapMemOutOfBounds, poke);
+    assertTraps(kTrapMemOutOfBounds, peek);
+  }
+
+  try {
+    assertEquals(growMem(15), 4);
+  } catch (e) {
+    assertEquals("object", typeof e);
+    assertEquals(e.message, "failed to allocate memory");
+    return;
+  }
+
+  for (offset = 262142; offset < 262148; offset++) {
+    poke(20);
+    assertEquals(peek(), 20);
+  }
+  for (offset = 1245184; offset < 1245188; offset++) {

[ahaas, 2016/06/24 11:10:15]

could you add a test for the upper bound?, e.g. by setting offset to 1245180 and
poke and peek?

[gdeepti, 2016/06/25 00:28:42]

Done.

+    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);
+
+  try {
+    assertEquals(growMem(1), 0);
+  } catch (e) {
+    assertEquals("object", typeof e);
+    assertEquals(e.message, "failed to allocate memory");
+    return;
+  }
+
+  for(offset = 0; offset <=65533; offset++) {
+    poke(20);
+    assertEquals(peek(), 20);
+  }
+
+  //TODO(gdeepti): Fix tests with correct write boundaries
+  //when runtime function is fixed.
+  for(offset = 65536; offset <= 65539; offset++) {
+    assertTraps(kTrapMemOutOfBounds, peek);
+  }
+}
+
+testGrowMemoryZeroInitialSize();
+
+function testGrowMemoryTrapMaxPagesZeroInitialMemory() {
+  var builder = genGrowMemoryBuilder();
+  var module = builder.instantiate();
+  var maxPages = 16385;
+  function growMem() { return module.exports.grow_memory(maxPages); }
+  try {
+    growMem();
+  } catch (e) {
+    assertEquals("object", typeof e);
+    if (e.message === "failed to allocate memory" ||

[ahaas, 2016/06/24 11:10:15]

How can both of these messages be possible?

[gdeepti, 2016/06/25 00:28:42]

Left over from when I was trying to catch windows failures, thanks for catching
this. Fixed here and in the case below. 

+        e.message === "memory access out of bounds") {
+      return;
+    }
+  }
+}
+
+testGrowMemoryTrapMaxPagesZeroInitialMemory();
+
+function testGrowMemoryTrapMaxPages() {
+  var builder = genGrowMemoryBuilder();
+  builder.addMemory(1, 1, false);
+  var module = builder.instantiate();
+  var maxPages = 16384;
+  function growMem() { return module.exports.grow_memory(maxPages); }
+  try {
+    growMem();
+  } catch (e) {
+    assertEquals("object", typeof e);
+    if (e.message === "failed to allocate memory" ||
+        e.message === "memory access out of bounds") {
+      return;
+    }
+  }
+}
+
+testGrowMemoryTrapMaxPages();
+
+function testGrowMemoryOobThrows() {
+  var builder = genGrowMemoryBuilder();
+  builder.addMemory(1, 1, false);
+  builder.addFunction("geti", kSig_i_ii)
+    .addBody([
+      kExprGetLocal, 0,
+      kExprGetLocal, 1,
+      kExprI32LoadMem, 0, 0,
+      kExprI32StoreMem, 0, 0
+    ])
+    .exportFunc();
+
+  var module = builder.instantiate();
+  var offset;
+
+  function read() { return module.exports.geti(0, offset); }
+  function write() { return module.exports.geti(offset, 0); }
+
+  for (offset = 0; offset < 65533; offset++) {
+    assertEquals(0, read());

[ahaas, 2016/06/24 11:10:15]

I don't understand this test. It seems to be either trivial if memory is zero
initialized, or I have no idea why it works.

[gdeepti, 2016/06/25 00:28:42]

I added this test as a sanity check for oob with growMemory from
module-memory.js before zero initializing memory, seems redundant now -
removing.    

+    assertEquals(0, write());
+  }
+
+  for (offset = 65534; offset < 66536; offset++) {
+    assertTraps(kTrapMemOutOfBounds, read);
+    assertTraps(kTrapMemOutOfBounds, write);
+  }
+
+  function resizeMem() { return module.exports.grow_memory(2); }
+
+  try {
+    assertEquals(1, resizeMem());
+  } catch (e) {
+    assertEquals("object", typeof e);
+    assertEquals(e.message, "failed to allocate memory");
+    return;
+  }
+
+
+  for (offset = 0; offset < 196605; offset++) {
+    assertEquals(0, read());
+    assertEquals(0, write());
+  }
+
+  for (offset = 196605; offset < 196610; offset++) {
+    assertTraps(kTrapMemOutOfBounds, read);
+    assertTraps(kTrapMemOutOfBounds, write);
+  }
+
+}
+
+testGrowMemoryOobThrows();