[llvm] r283376 - [asan] Reapply: Switch to using dynamic shadow offset on iOS

[Anna Zaks via llvm-commits]

Author: zaks
Date: Wed Oct  5 15:34:13 2016
New Revision: 283376

URL: http://llvm.org/viewvc/llvm-project?rev=283376&view=rev
Log:
[asan] Reapply: Switch to using dynamic shadow offset on iOS

The VM layout is not stable between iOS version releases, so switch to dynamic shadow offset.

This is the LLVM counterpart of https://reviews.llvm.org/D25218

Differential Revision: https://reviews.llvm.org/D25219

Modified:
    llvm/trunk/lib/Transforms/Instrumentation/AddressSanitizer.cpp

Modified: llvm/trunk/lib/Transforms/Instrumentation/AddressSanitizer.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Instrumentation/AddressSanitizer.cpp?rev=283376&r1=283375&r2=283376&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Instrumentation/AddressSanitizer.cpp (original)
+++ llvm/trunk/lib/Transforms/Instrumentation/AddressSanitizer.cpp Wed Oct  5 15:34:13 2016
@@ -69,7 +69,6 @@ static const uint64_t kDefaultShadowOffs
 static const uint64_t kDefaultShadowOffset64 = 1ULL << 44;
 static const uint64_t kDynamicShadowSentinel = ~(uint64_t)0;
 static const uint64_t kIOSShadowOffset32 = 1ULL << 30;
-static const uint64_t kIOSShadowOffset64 = 0x120200000;
 static const uint64_t kIOSSimShadowOffset32 = 1ULL << 30;
 static const uint64_t kIOSSimShadowOffset64 = kDefaultShadowOffset64;
 static const uint64_t kSmallX86_64ShadowOffset = 0x7FFF8000;  // < 2G.
@@ -434,7 +433,9 @@ static ShadowMapping getShadowMapping(Tr
       Mapping.Offset = kMIPS64_ShadowOffset64;
     else if (IsIOS)
       // If we're targeting iOS and x86, the binary is built for iOS simulator.
-      Mapping.Offset = IsX86_64 ? kIOSSimShadowOffset64 : kIOSShadowOffset64;
+      // We are using dynamic shadow offset on the 64-bit devices.
+      Mapping.Offset =
+        IsX86_64 ? kIOSSimShadowOffset64 : kDynamicShadowSentinel;
     else if (IsAArch64)
       Mapping.Offset = kAArch64_ShadowOffset64;
     else