Landing: Write protect executable pages in the VM.

runtime/vm/instructions_x64_test.cc

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/globals.h"
 #if defined(TARGET_ARCH_X64)
 
 #include "vm/assembler.h"
 #include "vm/instructions.h"
 #include "vm/stub_code.h"
@@ skipping 26 matching lines @@
   prologue_code_size = assembler->CodeSize();
   __ JmpPatchable(&StubCode::InstanceFunctionLookupLabel(), PP);
   __ JmpPatchable(&StubCode::AllocateArrayLabel(), PP);
   __ popq(PP);
   __ ret();
 }
 
 
 ASSEMBLER_TEST_RUN(Jump, test) {
   ASSERT(prologue_code_size != -1);
+  const Code& code = test->code();
+  const Instructions& instrs = Instructions::Handle(code.instructions());
+  bool status =
+      VirtualMemory::Protect(reinterpret_cast<void*>(instrs.EntryPoint()),
+                             instrs.size(),
+                             VirtualMemory::kReadWrite);
+  EXPECT(status);
   JumpPattern jump1(test->entry() + prologue_code_size, test->code());
   jump1.IsValid();
   EXPECT_EQ(StubCode::InstanceFunctionLookupLabel().address(),
             jump1.TargetAddress());
   JumpPattern jump2((test->entry() +
                      jump1.pattern_length_in_bytes() + prologue_code_size),
                     test->code());
   EXPECT_EQ(StubCode::AllocateArrayLabel().address(),
             jump2.TargetAddress());
   uword target1 = jump1.TargetAddress();
   uword target2 = jump2.TargetAddress();
   jump1.SetTargetAddress(target2);
   jump2.SetTargetAddress(target1);
   EXPECT_EQ(StubCode::AllocateArrayLabel().address(),
             jump1.TargetAddress());
   EXPECT_EQ(StubCode::InstanceFunctionLookupLabel().address(),
             jump2.TargetAddress());
 }
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_X64