Assembler changes for enabling GrowHeap in Wasm

test/cctest/test-wasm-relocation-disasm-arm.cc

+// Copyright 2016 the V8 project authors. All rights reserved.
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+//       notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+//       copyright notice, this list of conditions and the following
+//       disclaimer in the documentation and/or other materials provided
+//       with the distribution.
+//     * Neither the name of Google Inc. nor the names of its
+//       contributors may be used to endorse or promote products derived
+//       from this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#include <iostream>  // NOLINT(readability/streams)
+
+#include "src/v8.h"
+#include "test/cctest/cctest.h"
+
+#include "src/arm/assembler-arm-inl.h"
+#include "src/arm/simulator-arm.h"
+#include "src/disassembler.h"
+#include "src/factory.h"
+#include "src/ostreams.h"
+#include "test/cctest/compiler/c-signature.h"
+#include "test/cctest/compiler/call-tester.h"
+
+using namespace v8::base;
+using namespace v8::internal;
+using namespace v8::internal::compiler;
+
+#define __ assm.
+
+static int32_t DummyStaticFunction(Object* result) { return 1; }
+
+TEST(WasmRelocationArm) {
+  CcTest::InitializeVM();
+  Isolate* isolate = CcTest::i_isolate();
+  HandleScope scope(isolate);
+  v8::internal::byte buffer[4096];
+  DummyStaticFunction(NULL);
+  int32_t imm = 1234567;
+
+  Assembler assm(isolate, buffer, sizeof buffer);
+
+  __ mov(r0, Operand(imm, RelocInfo::WASM_HEAP_OBJECT));
+  __ mov(pc, Operand(lr));
+
+  CodeDesc desc;
+  assm.GetCode(&desc);
+  Handle<Code> code = isolate->factory()->NewCode(
+      desc, Code::ComputeFlags(Code::STUB), Handle<Code>());
+
+  CSignature0<int32_t> csig;
+  CodeRunner<int32_t> runnable(isolate, code, &csig);
+  int32_t ret_value = runnable.Call();
+  CHECK_EQ(ret_value, imm);
+
+#ifdef DEBUG
+  OFStream os(stdout);
+  code->Print(os);
+  ::printf("f() = %d\n\n", ret_value);
+#endif
+
+  // Initialize new buffer
+  v8::internal::byte new_buffer[4096];
+  size_t offset =
+      reinterpret_cast<byte*>(new_buffer) - reinterpret_cast<byte*>(buffer);

[Yang, 2016/03/03 06:21:56]

I don't see why the offset between buffers matters here. What you want to test
is that you can patch a new immediate into the code. Why not just do that?

[gdeepti1, 2016/03/03 22:59:15]

The context I guess is updating references by an offset when the memory buffers
for wasm are changed and that all the references are updated by the correct
offset. I see why it doesn't make as much sense here. Updated it to get rid of
the buffers. 

+
+  // Relocating code object
+  int mode_mask = (1 << RelocInfo::WASM_HEAP_OBJECT);
+  for (RelocIterator it(*code, mode_mask); !it.done(); it.next()) {
+    RelocInfo::Mode mode = it.rinfo()->rmode();
+    if (RelocInfo::IsWasmCodeEntry(mode)) {
+      it.rinfo()->set_target_address(it.rinfo()->target_address() + offset,

[Yang, 2016/03/03 06:21:56]

just write something new into here, like a imm_new = 7654321.

[gdeepti1, 2016/03/03 22:59:15]

references updated by an offset for now. 

+                                     SKIP_WRITE_BARRIER, SKIP_ICACHE_FLUSH);
+    }
+  }
+
+  // Call into relocated code object
+  ret_value = runnable.Call();
+  CHECK_EQ((imm + offset), ret_value);
+
+#ifdef DEBUG
+  code->Print(os);
+  ::printf("f() = %d\n\n", ret_value);
+#endif
+}
+
+#undef __