[asan] Remove special case mapping on Android/AArch64.

ASan shadow on Android starts at address 0 for both historic and
performance reasons. This is possible because the platform mandates
-pie, which makes lower memory region always available.

This is not such a good idea on 64-bit platforms because of MAP_32BIT
incompatibility.

This patch changes Android/AArch64 mapping to be the same as that of
Linux/AAarch64.

llvm-svn: 243548

diff --git a/compiler-rt/lib/asan/asan_mapping.h b/compiler-rt/lib/asan/asan_mapping.h
index f9e1a52..7e05db5 100644 (file)
--- a/compiler-rt/lib/asan/asan_mapping.h
+++ b/compiler-rt/lib/asan/asan_mapping.h
@@ -113,11 +113,12 @@ static const u64 kFreeBSD_ShadowOffset64 = 1ULL << 46;  // 0x400000000000
 static const u64 kWindowsShadowOffset32 = 3ULL << 28;  // 0x30000000
 
 #define SHADOW_SCALE kDefaultShadowScale
-#if SANITIZER_ANDROID
-# define SHADOW_OFFSET (0)
-#else
-# if SANITIZER_WORDSIZE == 32
-#  if defined(__mips__)
+
+
+#if SANITIZER_WORDSIZE == 32
+#  if SANITIZER_ANDROID
+#    define SHADOW_OFFSET (0)
+#  elif defined(__mips__)
 #    define SHADOW_OFFSET kMIPS32_ShadowOffset32
 #  elif SANITIZER_FREEBSD
 #    define SHADOW_OFFSET kFreeBSD_ShadowOffset32
@@ -130,7 +131,7 @@ static const u64 kWindowsShadowOffset32 = 3ULL << 28;  // 0x30000000
 #  else
 #    define SHADOW_OFFSET kDefaultShadowOffset32
 #  endif
-# else
+#else
 #  if defined(__aarch64__)
 #    define SHADOW_OFFSET kAArch64_ShadowOffset64
 #  elif defined(__powerpc64__)
@@ -148,7 +149,6 @@ static const u64 kWindowsShadowOffset32 = 3ULL << 28;  // 0x30000000
 #  else
 #   define SHADOW_OFFSET kDefaultShort64bitShadowOffset
 #  endif
-# endif
 #endif
 
 #define SHADOW_GRANULARITY (1ULL << SHADOW_SCALE)

diff --git a/llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp b/llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp
index 5dde5fe..47b736f 100644 (file)
--- a/llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp
+++ b/llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp
@@ -340,12 +340,12 @@ static ShadowMapping getShadowMapping(Triple &TargetTriple, int LongSize,
 
   ShadowMapping Mapping;
 
-  if (IsAndroid) {
+  if (LongSize == 32) {
     // Android is always PIE, which means that the beginning of the address
     // space is always available.
-    Mapping.Offset = 0;
-  } else if (LongSize == 32) {
-    if (IsMIPS32)
+    if (IsAndroid)
+      Mapping.Offset = 0;
+    else if (IsMIPS32)
       Mapping.Offset = kMIPS32_ShadowOffset32;
     else if (IsFreeBSD)
       Mapping.Offset = kFreeBSD_ShadowOffset32;