#else
uint32_t raw_addr = V8::RandomPrivate(isolate);
- // For our 32-bit mmap() hint, we pick a random address in the bottom
+ raw_addr &= 0x3ffff000;
+
+# ifdef __sun
+ // For our Solaris/illumos mmap hint, we pick a random address in the bottom
// half of the top half of the address space (that is, the third quarter).
// Because we do not MAP_FIXED, this will be treated only as a hint -- the
// system will not fail to mmap() because something else happens to already
// be mapped at our random address. We deliberately set the hint high enough
- // to get well above the system's break (that is, the heap); systems will
- // either try the hint and if that fails move higher (MacOS and other BSD
- // derivatives) or try the hint and if that fails allocate as if there were
- // no hint at all (Linux, Solaris, illumos and derivatives). The high hint
- // prevents the break from getting hemmed in at low values, ceding half of
- // the address space to the system heap.
- raw_addr &= 0x3ffff000;
+ // to get well above the system's break (that is, the heap); Solaris and
+ // illumos will try the hint and if that fails allocate as if there were
+ // no hint at all. The high hint prevents the break from getting hemmed in
+ // at low values, ceding half of the address space to the system heap.
raw_addr += 0x80000000;
+# else
+ // The range 0x20000000 - 0x60000000 is relatively unpopulated across a
+ // variety of ASLR modes (PAE kernel, NX compat mode, etc) and on macos
+ // 10.6 and 10.7.
+ raw_addr += 0x20000000;
+# endif
#endif
return reinterpret_cast<void*>(raw_addr);
}