MIPS: Fixed a bug in CopyBytes() and new test cases for MIPS macro assembler.

Port r16873 (c2880bc)

BUG=
TEST=cctest/test-macro-assembler-mips
R=plind44@gmail.com

Review URL: https://codereview.chromium.org/24266007

Patch from Balazs Kilvady <kilvadyb@homejinni.com>.

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@16904 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/mips/macro-assembler-mips.cc

@@ -3220,11 +3220,10 @@ void MacroAssembler::CopyBytes(Register src,
                                Register dst,
                                Register length,
                                Register scratch) {
-  Label align_loop, align_loop_1, word_loop, byte_loop, byte_loop_1, done;
+  Label align_loop_1, word_loop, byte_loop, byte_loop_1, done;
 
   // Align src before copying in word size chunks.
-  bind(&align_loop);
-  Branch(&done, eq, length, Operand(zero_reg));
+  Branch(&byte_loop, le, length, Operand(kPointerSize));
   bind(&align_loop_1);
   And(scratch, src, kPointerSize - 1);
   Branch(&word_loop, eq, scratch, Operand(zero_reg));
@@ -3233,7 +3232,7 @@ void MacroAssembler::CopyBytes(Register src,
   sb(scratch, MemOperand(dst));
   Addu(dst, dst, 1);
   Subu(length, length, Operand(1));
-  Branch(&byte_loop_1, ne, length, Operand(zero_reg));
+  Branch(&align_loop_1, ne, length, Operand(zero_reg));
 
   // Copy bytes in word size chunks.
   bind(&word_loop);

test/cctest/cctest.gyp

@@ -147,6 +147,7 @@
           'sources': [
             'test-assembler-mips.cc',
             'test-disasm-mips.cc',
+            'test-macro-assembler-mips.cc'
           ],
         }],
         [ 'OS=="linux"', {

test/cctest/test-macro-assembler-mips.cc

+// Copyright 2013 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 <stdlib.h>
+
+#include "v8.h"
+#include "macro-assembler.h"
+#include "mips/macro-assembler-mips.h"
+#include "mips/simulator-mips.h"
+#include "cctest.h"
+
+
+using namespace v8::internal;
+
+typedef void* (*F)(int x, int y, int p2, int p3, int p4);
+
+#define __ masm->
+
+
+static byte to_non_zero(int n) {
+  return static_cast<unsigned>(n) % 255 + 1;
+}
+
+
+static bool all_zeroes(const byte* beg, const byte* end) {
+  CHECK(beg);
+  CHECK(beg <= end);
+  while (beg < end) {
+    if (*beg++ != 0)
+      return false;
+  }
+  return true;
+}
+
+
+TEST(CopyBytes) {
+  CcTest::InitializeVM();
+  Isolate* isolate = Isolate::Current();
+  HandleScope handles(isolate);
+
+  const int data_size = 1 * KB;
+  size_t act_size;
+
+  // Allocate two blocks to copy data between.
+  byte* src_buffer = static_cast<byte*>(OS::Allocate(data_size, &act_size, 0));
+  CHECK(src_buffer);
+  CHECK(act_size >= static_cast<size_t>(data_size));
+  byte* dest_buffer = static_cast<byte*>(OS::Allocate(data_size, &act_size, 0));
+  CHECK(dest_buffer);
+  CHECK(act_size >= static_cast<size_t>(data_size));
+
+  // Storage for a0 and a1.
+  byte* a0_;
+  byte* a1_;
+
+  MacroAssembler assembler(isolate, NULL, 0);
+  MacroAssembler* masm = &assembler;
+
+  // Code to be generated: The stuff in CopyBytes followed by a store of a0 and
+  // a1, respectively.
+  __ CopyBytes(a0, a1, a2, a3);
+  __ li(a2, Operand(reinterpret_cast<int>(&a0_)));
+  __ li(a3, Operand(reinterpret_cast<int>(&a1_)));
+  __ sw(a0, MemOperand(a2));
+  __ jr(ra);
+  __ sw(a1, MemOperand(a3));
+
+  CodeDesc desc;
+  masm->GetCode(&desc);
+  Object* code = isolate->heap()->CreateCode(
+      desc,
+      Code::ComputeFlags(Code::STUB),
+      Handle<Code>())->ToObjectChecked();
+  CHECK(code->IsCode());
+
+  ::F f = FUNCTION_CAST< ::F>(Code::cast(code)->entry());
+
+  // Initialise source data with non-zero bytes.
+  for (int i = 0; i < data_size; i++) {
+    src_buffer[i] = to_non_zero(i);
+  }
+
+  const int fuzz = 11;
+
+  for (int size = 0; size < 600; size++) {
+    for (const byte* src = src_buffer; src < src_buffer + fuzz; src++) {
+      for (byte* dest = dest_buffer; dest < dest_buffer + fuzz; dest++) {
+        memset(dest_buffer, 0, data_size);
+        CHECK(dest + size < dest_buffer + data_size);
+        (void) CALL_GENERATED_CODE(f, reinterpret_cast<int>(src),
+                                      reinterpret_cast<int>(dest), size, 0, 0);
+        // a0 and a1 should point at the first byte after the copied data.
+        CHECK_EQ(src + size, a0_);
+        CHECK_EQ(dest + size, a1_);
+        // Check that we haven't written outside the target area.
+        CHECK(all_zeroes(dest_buffer, dest));
+        CHECK(all_zeroes(dest + size, dest_buffer + data_size));
+        // Check the target area.
+        CHECK_EQ(0, memcmp(src, dest, size));
+      }
+    }
+  }
+
+  // Check that the source data hasn't been clobbered.
+  for (int i = 0; i < data_size; i++) {
+    CHECK(src_buffer[i] == to_non_zero(i));
+  }
+}
+
+
+
+#undef __