[compiler-rt] r226639 - [sanitizer] First step toward supporting 42-bit AS on aarch64

[Kostya Serebryany]

Author: kcc
Date: Tue Jan 20 20:11:05 2015
New Revision: 226639

URL: http://llvm.org/viewvc/llvm-project?rev=226639&view=rev
Log:
[sanitizer] First step toward supporting 42-bit AS on aarch64

aarch64-linux kernel has configurable 39, 42 or 47 bit virtual address
space.  Most distros AFAIK use 42-bit VA right now, but there are also
39-bit VA users too.  The ppc64 handling can be used for this just fine
and support all the 3 sizes.

There are other issues, like allocator32 not really being able to support
the larger addres spaces, and hardcoded 39-bit address space size in other
macros.

Patch by Jakub Jelinek.

Modified:
    compiler-rt/trunk/lib/sanitizer_common/sanitizer_posix.cc

Modified: compiler-rt/trunk/lib/sanitizer_common/sanitizer_posix.cc
URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/sanitizer_common/sanitizer_posix.cc?rev=226639&r1=226638&r2=226639&view=diff
==============================================================================
--- compiler-rt/trunk/lib/sanitizer_common/sanitizer_posix.cc (original)
+++ compiler-rt/trunk/lib/sanitizer_common/sanitizer_posix.cc Tue Jan 20 20:11:05 2015
@@ -78,16 +78,15 @@ static uptr GetKernelAreaSize() {
 
 uptr GetMaxVirtualAddress() {
 #if SANITIZER_WORDSIZE == 64
-# if defined(__powerpc64__)
+# if defined(__powerpc64__) || defined(__aarch64__)
   // On PowerPC64 we have two different address space layouts: 44- and 46-bit.
   // We somehow need to figure out which one we are using now and choose
   // one of 0x00000fffffffffffUL and 0x00003fffffffffffUL.
   // Note that with 'ulimit -s unlimited' the stack is moved away from the top
   // of the address space, so simply checking the stack address is not enough.
   // This should (does) work for both PowerPC64 Endian modes.
+  // Similarly, aarch64 has multiple address space layouts: 39, 42 and 47-bit.
   return (1ULL << (MostSignificantSetBitIndex(GET_CURRENT_FRAME()) + 1)) - 1;
-# elif defined(__aarch64__)
-  return (1ULL << 39) - 1;
 # elif defined(__mips64)
   return (1ULL << 40) - 1;  // 0x000000ffffffffffUL;
 # else