Index: compiler-rt/trunk/lib/asan/asan_mapping.h
===================================================================
--- compiler-rt/trunk/lib/asan/asan_mapping.h
+++ compiler-rt/trunk/lib/asan/asan_mapping.h
@@ -87,11 +87,7 @@
 static const u64 kDefaultShort64bitShadowOffset = 0x7FFF8000;  // < 2G.
 static const u64 kAArch64_ShadowOffset64 = 1ULL << 36;
 static const u64 kMIPS32_ShadowOffset32 = 0x0aaa0000;
-#if defined(__powerpc64__) && defined(__BIG_ENDIAN__)
 static const u64 kPPC64_ShadowOffset64 = 1ULL << 41;
-#elif defined(__powerpc64__) && defined(__LITTLE_ENDIAN__)
-static const u64 kPPC64_ShadowOffset64 = 1ULL << 43;
-#endif
 static const u64 kFreeBSD_ShadowOffset32 = 1ULL << 30;  // 0x40000000
 static const u64 kFreeBSD_ShadowOffset64 = 1ULL << 46;  // 0x400000000000
 
Index: compiler-rt/trunk/lib/sanitizer_common/sanitizer_posix.cc
===================================================================
--- compiler-rt/trunk/lib/sanitizer_common/sanitizer_posix.cc
+++ compiler-rt/trunk/lib/sanitizer_common/sanitizer_posix.cc
@@ -78,15 +78,14 @@
 
 uptr GetMaxVirtualAddress() {
 #if SANITIZER_WORDSIZE == 64
-# if defined(__powerpc64__) && defined(__BIG_ENDIAN__)
+# if defined(__powerpc64__)
   // 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.
-  return (1ULL << 44) - 1;  // 0x00000fffffffffffUL
-# elif defined(__powerpc64__) && defined(__LITTLE_ENDIAN__)
-  return (1ULL << 46) - 1;  // 0x00003fffffffffffUL
+  // This should (does) work for both PowerPC64 Endian modes.
+  return (1ULL << (MostSignificantSetBitIndex(GET_CURRENT_FRAME()) + 1)) - 1;
 # elif defined(__aarch64__)
   return (1ULL << 39) - 1;
 # else
Index: compiler-rt/trunk/test/asan/TestCases/debug_ppc64_mapping.cc
===================================================================
--- compiler-rt/trunk/test/asan/TestCases/debug_ppc64_mapping.cc
+++ compiler-rt/trunk/test/asan/TestCases/debug_ppc64_mapping.cc
@@ -0,0 +1,37 @@
+// RUN: %clang_asan -O0 %s -o %t
+// RUN: env ASAN_OPTIONS=verbosity=0 %run %t 2>&1 | FileCheck %s --check-prefix=CHECK-PPC64-V0
+// RUN: env ASAN_OPTIONS=verbosity=2 %run %t 2>&1 | FileCheck %s --check-prefix=CHECK-PPC64
+// REQUIRES: powerpc64-supported-target
+
+#include <stdio.h>
+
+int main() {
+// CHECK-PPC64: || `[{{0x0a0|0x040}}000000000, {{0x3ff|0x0ff}}fffffffff]` || HighMem    ||
+// CHECK-PPC64: || `[{{0x034|0x028}}000000000, {{0x09f|0x03f}}fffffffff]` || HighShadow ||
+// CHECK-PPC64: || `[{{0x024|0x024}}000000000, {{0x033|0x027}}fffffffff]` || ShadowGap  ||
+// CHECK-PPC64: || `[0x020000000000, 0x023fffffffff]`       || LowShadow  ||
+// CHECK-PPC64: || `[0x000000000000, 0x01ffffffffff]`       || LowMem     ||
+//
+  printf("ppc64 eyecatcher \n");
+// CHECK-PPC64-V0: ppc64 eyecatcher
+
+  return 0;
+}
+
+/*
+ * Two different signatures noted at the time of writing.
+Newish kernel: (64TB address range support, starting with kernel version 3.7)
+|| `[0x0a0000000000, 0x3fffffffffff]` || HighMem    ||
+|| `[0x034000000000, 0x09ffffffffff]` || HighShadow ||
+|| `[0x024000000000, 0x033fffffffff]` || ShadowGap  ||
+|| `[0x020000000000, 0x023fffffffff]` || LowShadow  ||
+|| `[0x000000000000, 0x01ffffffffff]` || LowMem     ||
+
+Oldish kernel:
+|| `[0x040000000000, 0x0fffffffffff]` || HighMem    ||
+|| `[0x028000000000, 0x03ffffffffff]` || HighShadow ||
+|| `[0x024000000000, 0x027fffffffff]` || ShadowGap  ||
+|| `[0x020000000000, 0x023fffffffff]` || LowShadow  ||
+|| `[0x000000000000, 0x01ffffffffff]` || LowMem     ||
+*/
+