PowerPC][asan] Update asan to handle changed memory layouts in newer kernels

[seurer]

Summary

[PowerPC][asan] Update asan to handle changed memory layouts in newer kernels

In more recent Linux kernels with 47 bit VMAs the layout of virtual memory
for powerpc64 changed causing the address sanitizer to not work properly. This
patch adds support for 47 bit VMA kernels for powerpc64 and fixes up test
cases.

There is an associated patch for trunk. https://reviews.llvm.org/D40907

Tested on several 4.x and 3.x kernel releases.

lib/asan/asan_mapping.h

static const u64 kDefaultShort64bitShadowOffset =
     0x7FFFFFFF & (~0xFFFULL << kDefaultShadowScale);  // < 2G.
 static const u64 kIosShadowOffset32 = 1ULL << 30;  // 0x40000000
 static const u64 kIosShadowOffset64 = 0x120200000;
 static const u64 kIosSimShadowOffset32 = 1ULL << 30;
 static const u64 kIosSimShadowOffset64 = kDefaultShadowOffset64;
 static const u64 kAArch64_ShadowOffset64 = 1ULL << 36;
 static const u64 kMIPS32_ShadowOffset32 = 0x0aaa0000;
 static const u64 kMIPS64_ShadowOffset64 = 1ULL << 37;
-static const u64 kPPC64_ShadowOffset64 = 1ULL << 41;
+static const u64 kPPC64_ShadowOffset64 = 1ULL << 44;
 static const u64 kSystemZ_ShadowOffset64 = 1ULL << 52;
 static const u64 kFreeBSD_ShadowOffset32 = 1ULL << 30;  // 0x40000000
 static const u64 kFreeBSD_ShadowOffset64 = 1ULL << 46;  // 0x400000000000
 static const u64 kNetBSD_ShadowOffset64 = 1ULL << 46;  // 0x400000000000
 static const u64 kWindowsShadowOffset32 = 3ULL << 28;  // 0x30000000
 
 #define SHADOW_SCALE kDefaultShadowScale
 

test/asan/TestCases/debug_ppc64_mapping.cc

 // RUN: %clang_asan -O0 %s -o %t
 // RUN: %env_asan_opts=verbosity=0 %run %t 2>&1 | FileCheck %s --check-prefix=CHECK-PPC64-V0
 // RUN: %env_asan_opts=verbosity=2 %run %t 2>&1 | FileCheck %s --check-prefix=CHECK-PPC64
 // REQUIRES: powerpc64-target-arch
 
 #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     ||
+// CHECK-PPC64: || `[{{0x180|0x0a0|0x040}}000000000, {{0x3ff|0x0ff}}fffffffff]` || HighMem    ||
+// CHECK-PPC64: || `[{{0x130|0x034|0x028}}000000000, {{0x17f|0x09f|0x03f}}fffffffff]` || HighShadow ||
+// CHECK-PPC64: || `[{{0x120|0x024|0x024}}000000000, {{0x12f|0x033|0x027}}fffffffff]` || ShadowGap  ||
+// CHECK-PPC64: || `[{{0x100|0x020}}000000000, {{0x11f|0x023}}fffffffff]`       || LowShadow  ||
+// CHECK-PPC64: || `[0x000000000000, {{0x0ff|0x01f}}fffffffff]`       || LowMem     ||
 //
   printf("ppc64 eyecatcher \n");
 // CHECK-PPC64-V0: ppc64 eyecatcher
 
   return 0;
 }
 
 /*
- * Two different signatures noted at the time of writing.
+ * Three different signatures noted.
+Newer kernel: (starting with kernel version 4.?)
+|| `[0x180000000000, 0x3fffffffffff]` || HighMem    ||
+|| `[0x130000000000, 0x17ffffffffff]` || HighShadow ||
+|| `[0x120000000000, 0x12ffffffffff]` || ShadowGap  ||
+|| `[0x100000000000, 0x11ffffffffff]` || LowShadow  ||
+|| `[0x000000000000, 0x0fffffffffff]` || LowMem     ||
+
 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     ||
 */