Backport hash collision workaround to 3.6.

test/cctest/test-hashing.cc

Index: test/cctest/test-hashing.cc
===================================================================
--- test/cctest/test-hashing.cc	(revision 0)
+++ test/cctest/test-hashing.cc	(revision 0)
@@ -0,0 +1,172 @@
+// Copyright 2011 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 "factory.h"
+#include "macro-assembler.h"
+#include "cctest.h"
+#include "code-stubs.h"
+#include "objects.h"
+
+#ifdef USE_SIMULATOR
+#include "simulator.h"
+#endif
+
+using namespace v8::internal;
+
+
+typedef uint32_t (*HASH_FUNCTION)();
+
+static v8::Persistent<v8::Context> env;
+
+#define __ masm->
+
+
+void generate(MacroAssembler* masm, i::Vector<const char> string) {
+  // GenerateHashInit takes the first character as an argument so it can't
+  // handle the zero length string.
+  ASSERT(string.length() > 0);
+#ifdef V8_TARGET_ARCH_IA32
+  __ push(ebx);
+  __ push(ecx);
+  __ mov(eax, Immediate(0));
+  __ mov(ebx, Immediate(string.at(0)));
+  StringHelper::GenerateHashInit(masm, eax, ebx, ecx);
+  for (int i = 1; i < string.length(); i++) {
+    __ mov(ebx, Immediate(string.at(i)));
+    StringHelper::GenerateHashAddCharacter(masm, eax, ebx, ecx);
+  }
+  StringHelper::GenerateHashGetHash(masm, eax, ecx);
+  __ pop(ecx);
+  __ pop(ebx);
+  __ Ret();
+#elif V8_TARGET_ARCH_X64
+  __ push(kRootRegister);
+  __ InitializeRootRegister();
+  __ push(rbx);
+  __ push(rcx);
+  __ movq(rax, Immediate(0));
+  __ movq(rbx, Immediate(string.at(0)));
+  StringHelper::GenerateHashInit(masm, rax, rbx, rcx);
+  for (int i = 1; i < string.length(); i++) {
+    __ movq(rbx, Immediate(string.at(i)));
+    StringHelper::GenerateHashAddCharacter(masm, rax, rbx, rcx);
+  }
+  StringHelper::GenerateHashGetHash(masm, rax, rcx);
+  __ pop(rcx);
+  __ pop(rbx);
+  __ pop(kRootRegister);
+  __ Ret();
+#elif V8_TARGET_ARCH_ARM
+  __ push(kRootRegister);
+  __ InitializeRootRegister();
+
+  __ mov(r0, Operand(0));
+  __ mov(ip, Operand(string.at(0)));
+  StringHelper::GenerateHashInit(masm, r0, ip);
+  for (int i = 1; i < string.length(); i++) {
+    __ mov(ip, Operand(string.at(i)));
+    StringHelper::GenerateHashAddCharacter(masm, r0, ip);
+  }
+  StringHelper::GenerateHashGetHash(masm, r0);
+  __ pop(kRootRegister);
+  __ mov(pc, Operand(lr));
+#elif V8_TARGET_ARCH_MIPS
+  __ push(kRootRegister);
+  __ InitializeRootRegister();
+
+  __ li(v0, Operand(0));
+  __ li(t1, Operand(string.at(0)));
+  StringHelper::GenerateHashInit(masm, v0, t1);
+  for (int i = 1; i < string.length(); i++) {
+    __ li(t1, Operand(string.at(i)));
+    StringHelper::GenerateHashAddCharacter(masm, v0, t1);
+  }
+  StringHelper::GenerateHashGetHash(masm, v0);
+  __ pop(kRootRegister);
+  __ jr(ra);
+  __ nop();
+#endif
+}
+
+
+void check(i::Vector<const char> string) {
+  v8::HandleScope scope;
+  v8::internal::byte buffer[2048];
+  MacroAssembler masm(Isolate::Current(), buffer, sizeof buffer);
+
+  generate(&masm, string);
+
+  CodeDesc desc;
+  masm.GetCode(&desc);
+  Code* code = Code::cast(HEAP->CreateCode(
+      desc,
+      Code::ComputeFlags(Code::STUB),
+      Handle<Object>(HEAP->undefined_value()))->ToObjectChecked());
+  CHECK(code->IsCode());
+
+  HASH_FUNCTION hash = FUNCTION_CAST<HASH_FUNCTION>(code->entry());
+  Handle<String> v8_string = FACTORY->NewStringFromAscii(string);
+  v8_string->set_hash_field(String::kEmptyHashField);
+#ifdef USE_SIMULATOR
+  uint32_t codegen_hash =
+      reinterpret_cast<uint32_t>(CALL_GENERATED_CODE(hash, 0, 0, 0, 0, 0));
+#else
+  uint32_t codegen_hash = hash();
+#endif
+  uint32_t runtime_hash = v8_string->Hash();
+  CHECK(runtime_hash == codegen_hash);
+}
+
+
+void check_twochars(char a, char b) {
+  char ab[2] = {a, b};
+  check(i::Vector<const char>(ab, 2));
+}
+
+
+TEST(StringHash) {
+  if (env.IsEmpty()) env = v8::Context::New();
+  for (int a = 0; a < String::kMaxAsciiCharCode; a++) {
+    // Numbers are hashed differently.
+    if (a >= '0' && a <= '9') continue;
+    for (int b = 0; b < String::kMaxAsciiCharCode; b++) {
+      if (b >= '0' && b <= '9') continue;
+      check_twochars(static_cast<char>(a), static_cast<char>(b));
+    }
+  }
+  check(i::Vector<const char>("*",       1));
+  check(i::Vector<const char>(".zZ",     3));
+  check(i::Vector<const char>("muc",     3));
+  check(i::Vector<const char>("(>'_')>", 7));
+  check(i::Vector<const char>("-=[ vee eight ftw ]=-", 21));
+}
+
+#undef __