@@ -, +, @@ 
 ia64
---
 js/src/jit/ProcessExecutableMemory.cpp | 25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)
--- a/js/src/jit/ProcessExecutableMemory.cpp	
+++ a/js/src/jit/ProcessExecutableMemory.cpp	
@@ -248,7 +248,32 @@ static void* ComputeRandomAllocationAddress() {
   // x64 CPUs have a 48-bit address space and on some platforms the OS will
   // give us access to 47 bits, so to be safe we right shift by 18 to leave
   // 46 bits.
+# ifdef __ia64__
+  // On ia64 virtual address space looks like one of:
+  //   virt_addr_64 = [ <63..61> | <unimplemented> | L3 | L2 | L1 | offset ]
+  //   virt_addr_64 = [ <63..61> | <unimplemented> | L4 | L3 | L2 | L1 | offset ]
+  // where L{1..L4} are page tables. Each page table (except top-level L3 or L4)
+  // is itself a page-size entry and can store PageSize / 8 entries. Top-level
+  // entry is 1/8 of of L1/L2 (as 3 upper bits are part of <63..61> address part).
+  // Note: that makes addressable size directly depend on page size.
+  //
+  // We conservatively assume 3 levels of page tables here. This makes the
+  // following formula:
+  //   L3     = log2(PAGE / 8 / 8) = log2(PAGE / 8) - 3
+  //   L2                          = log2(PAGE / 8)
+  //   L1                          = log2(PAGE / 8)
+  //   offset = log2(PAGE)         = log2(PAGE / 8) + 3
+  // thus
+  //  L3 + L2 + L1 + offset = 4 * log2(PAGE / 8)
+  // For more details see http://www.ia64-linux.org/doc/IA64linuxkernel.PDF
+  // (slide 19: "user regions").
+  static uint64_t ia64_virt_bits = std::min<uint64_t>(
+      4 * (mozilla::FloorLog2(gc::SystemPageSize() / 8)),
+      46);
+  rand >>= (64 - ia64_virt_bits);
+# else
   rand >>= 18;
+# endif
 #else
   // On 32-bit, right shift by 34 to leave 30 bits, range [0, 1GiB). Then add
   // 512MiB to get range [512MiB, 1.5GiB), or [0x20000000, 0x60000000). This
--