[cctest][mac] Enable MAP_JIT on tests that need RWX memory.

The icache and jump-table-assembler tests need memory that is both
writable and executable. On Mac, to do this we need to pass MAP_JIT to
mmap which is wired with the VirtualMemory::JitPermission flag.

Change-Id: If8236fa8983a4a59ef39fe777f26a02103dc6f75
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2637227Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Commit-Queue: Pierre Langlois <pierre.langlois@arm.com>
Cr-Commit-Position: refs/heads/master@{#72217}

test/cctest/test-icache.cc

@@ -173,7 +173,8 @@ TEST(TestFlushICacheOfWritableAndExecutable) {
   HandleScope handles(isolate);
 
   for (int i = 0; i < kNumIterations; ++i) {
-    auto buffer = AllocateAssemblerBuffer(kBufferSize);
+    auto buffer = AllocateAssemblerBuffer(kBufferSize, nullptr,
+                                          VirtualMemory::kMapAsJittable);
 
     // Allow calling the function from C++.
     auto f = GeneratedCode<F0>::FromBuffer(isolate, buffer->start());

test/cctest/wasm/test-jump-table-assembler.cc

@@ -232,7 +232,8 @@ TEST(JumpTablePatchingStress) {
   constexpr int kNumberOfPatcherThreads = 3;
 
   STATIC_ASSERT(kAssemblerBufferSize >= kJumpTableSize);
-  auto buffer = AllocateAssemblerBuffer(kAssemblerBufferSize);
+  auto buffer = AllocateAssemblerBuffer(kAssemblerBufferSize, nullptr,
+                                        VirtualMemory::kMapAsJittable);
   byte* thunk_slot_buffer = buffer->start() + kBufferSlotStartOffset;
 
   std::bitset<kAvailableBufferSlots> used_thunk_slots;

test/common/assembler-tester.h

@@ -15,31 +15,32 @@ namespace internal {
 
 class TestingAssemblerBuffer : public AssemblerBuffer {
  public:
-  TestingAssemblerBuffer(size_t requested, void* address) {
+  TestingAssemblerBuffer(
+      size_t requested, void* address,
+      VirtualMemory::JitPermission jit_permission = VirtualMemory::kNoJit) {
     size_t page_size = v8::internal::AllocatePageSize();
     size_t alloc_size = RoundUp(requested, page_size);
     CHECK_GE(kMaxInt, alloc_size);
-    size_ = static_cast<int>(alloc_size);
-    buffer_ = static_cast<byte*>(AllocatePages(GetPlatformPageAllocator(),
-                                               address, alloc_size, page_size,
-                                               v8::PageAllocator::kReadWrite));
-    CHECK_NOT_NULL(buffer_);
+    reservation_ = VirtualMemory(GetPlatformPageAllocator(), alloc_size,
+                                 address, page_size, jit_permission);
+    CHECK(reservation_.IsReserved());
+    MakeWritable();
   }
 
-  ~TestingAssemblerBuffer() {
-    CHECK(FreePages(GetPlatformPageAllocator(), buffer_, size_));
-  }
+  ~TestingAssemblerBuffer() { reservation_.Free(); }
 
-  byte* start() const override { return buffer_; }
+  byte* start() const override {
+    return reinterpret_cast<byte*>(reservation_.address());
+  }
 
-  int size() const override { return size_; }
+  int size() const override { return static_cast<int>(reservation_.size()); }
 
   std::unique_ptr<AssemblerBuffer> Grow(int new_size) override {
     FATAL("Cannot grow TestingAssemblerBuffer");
   }
 
   std::unique_ptr<AssemblerBuffer> CreateView() const {
-    return ExternalAssemblerBuffer(buffer_, size_);
+    return ExternalAssemblerBuffer(start(), size());
   }
 
   void MakeExecutable() {
@@ -48,35 +49,36 @@ class TestingAssemblerBuffer : public AssemblerBuffer {
     // some older ARM kernels there is a bug which causes an access error on
     // cache flush instructions to trigger access error on non-writable memory.
     // See https://bugs.chromium.org/p/v8/issues/detail?id=8157
-    FlushInstructionCache(buffer_, size_);
+    FlushInstructionCache(start(), size());
 
-    bool result = SetPermissions(GetPlatformPageAllocator(), buffer_, size_,
+    bool result = SetPermissions(GetPlatformPageAllocator(), start(), size(),
                                  v8::PageAllocator::kReadExecute);
     CHECK(result);
   }
 
   void MakeWritable() {
-    bool result = SetPermissions(GetPlatformPageAllocator(), buffer_, size_,
+    bool result = SetPermissions(GetPlatformPageAllocator(), start(), size(),
                                  v8::PageAllocator::kReadWrite);
     CHECK(result);
   }
 
   // TODO(wasm): Only needed for the "test-jump-table-assembler.cc" tests.
   void MakeWritableAndExecutable() {
-    bool result = SetPermissions(GetPlatformPageAllocator(), buffer_, size_,
+    bool result = SetPermissions(GetPlatformPageAllocator(), start(), size(),
                                  v8::PageAllocator::kReadWriteExecute);
     CHECK(result);
   }
 
  private:
-  byte* buffer_;
-  int size_;
+  VirtualMemory reservation_;
 };
 
 static inline std::unique_ptr<TestingAssemblerBuffer> AllocateAssemblerBuffer(
     size_t requested = v8::internal::AssemblerBase::kDefaultBufferSize,
-    void* address = nullptr) {
-  return std::make_unique<TestingAssemblerBuffer>(requested, address);
+    void* address = nullptr,
+    VirtualMemory::JitPermission jit_permission = VirtualMemory::kNoJit) {
+  return std::make_unique<TestingAssemblerBuffer>(requested, address,
+                                                  jit_permission);
 }
 
 }  // namespace internal