From: Evgeniy Stepanov <eugeni.stepanov@gmail.com>
Date: Wed, 29 Jul 2015 18:22:25 +0000 (+0000)
Subject: [asan] Remove special case mapping on Android/AArch64.
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=8ad735a538bda0ca42a18d4e6917d54e6dedb290;p=oota-llvm.git

[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.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@243548 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/Transforms/Instrumentation/AddressSanitizer.cpp b/lib/Transforms/Instrumentation/AddressSanitizer.cpp
index 5dde5fed0d2..47b736f3cd1 100644
--- a/lib/Transforms/Instrumentation/AddressSanitizer.cpp
+++ b/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;