Mark optimized modulo and memcpy code pages -w after writing them.

BUG=91245

Review URL: http://codereview.chromium.org/7538028

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@8780 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/ia32/codegen-ia32.cc

@@ -255,6 +255,7 @@ OS::MemCopyFunction CreateMemCopyFunction() {
   ASSERT(desc.reloc_size == 0);
 
   CPU::FlushICache(buffer, actual_size);
+  OS::ProtectCode(buffer, actual_size);
   return FUNCTION_CAST<OS::MemCopyFunction>(buffer);
 }
 

src/platform-posix.cc

@@ -70,6 +70,12 @@ intptr_t OS::MaxVirtualMemory() {
 }
 
 
+// Get rid of writable permission on code allocations.
+void OS::ProtectCode(void* address, const size_t size) {
+  mprotect(address, size, PROT_READ | PROT_EXEC);
+}
+
+
 // Create guard pages.
 void OS::Guard(void* address, const size_t size) {
   mprotect(address, size, PROT_NONE);

src/platform-win32.cc

@@ -957,6 +957,12 @@ void OS::Free(void* address, const size_t size) {
 }
 
 
+void OS::ProtectCode(void* address, const size_t size) {
+  DWORD old_protect;
+  VirtualProtect(address, size, PAGE_EXECUTE_READ, &old_protect);
+}
+
+
 void OS::Guard(void* address, const size_t size) {
   DWORD oldprotect;
   VirtualProtect(address, size, PAGE_READONLY | PAGE_GUARD, &oldprotect);

src/platform.h

@@ -207,6 +207,9 @@ class OS {
                         bool is_executable);
   static void Free(void* address, const size_t size);
 
+  // Mark code segments non-writable.
+  static void ProtectCode(void* address, const size_t size);
+
   // Assign memory as a guard page so that access will cause an exception.
   static void Guard(void* address, const size_t size);
 

src/x64/codegen-x64.cc

@@ -132,6 +132,7 @@ ModuloFunction CreateModuloFunction() {
 
   CodeDesc desc;
   masm.GetCode(&desc);
+  OS::ProtectCode(buffer, actual_size);
   // Call the function from C++ through this pointer.
   return FUNCTION_CAST<ModuloFunction>(buffer);
 }