// This causes VirtualMemory::Commit to not always commit the memory region
// specified.
-static void* GetRandomAddr() {
- Isolate* isolate = Isolate::UncheckedCurrent();
- // Note that the current isolate isn't set up in a call path via
- // CpuFeatures::Probe. We don't care about randomization in this case because
- // the code page is immediately freed.
- if (isolate != NULL) {
- // The address range used to randomize RWX allocations in OS::Allocate
- // Try not to map pages into the default range that windows loads DLLs
- // Use a multiple of 64k to prevent committing unused memory.
- // Note: This does not guarantee RWX regions will be within the
- // range kAllocationRandomAddressMin to kAllocationRandomAddressMax
-#ifdef V8_HOST_ARCH_64_BIT
- static const intptr_t kAllocationRandomAddressMin = 0x0000000080000000;
- static const intptr_t kAllocationRandomAddressMax = 0x000003FFFFFF0000;
-#else
- static const intptr_t kAllocationRandomAddressMin = 0x04000000;
- static const intptr_t kAllocationRandomAddressMax = 0x3FFF0000;
-#endif
- uintptr_t address =
- (isolate->random_number_generator()->NextInt() << kPageSizeBits) |
- kAllocationRandomAddressMin;
- address &= kAllocationRandomAddressMax;
- return reinterpret_cast<void *>(address);
- }
- return NULL;
-}
-
-
static void* RandomizedVirtualAlloc(size_t size, int action, int protection) {
LPVOID base = NULL;
if (protection == PAGE_EXECUTE_READWRITE || protection == PAGE_NOACCESS) {
// For exectutable pages try and randomize the allocation address
for (size_t attempts = 0; base == NULL && attempts < 3; ++attempts) {
- base = VirtualAlloc(GetRandomAddr(), size, action, protection);
+ base = VirtualAlloc(OS::GetRandomMmapAddr(), size, action, protection);
}
}