[llvm] r296405 - [AddressSanitizer] Put shadow at 0 for Fuchsia

[Petr Hosek via llvm-commits]

Author: phosek
Date: Mon Feb 27 16:49:37 2017
New Revision: 296405

URL: http://llvm.org/viewvc/llvm-project?rev=296405&view=rev
Log:
[AddressSanitizer] Put shadow at 0 for Fuchsia

The Fuchsia ASan runtime reserves the low part of the address space.

Patch by Roland McGrath

Differential Revision: https://reviews.llvm.org/D30426

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=296405&r1=296404&r2=296405&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Instrumentation/AddressSanitizer.cpp (original)
+++ llvm/trunk/lib/Transforms/Instrumentation/AddressSanitizer.cpp Mon Feb 27 16:49:37 2017
@@ -394,6 +394,7 @@ static ShadowMapping getShadowMapping(Tr
                   TargetTriple.getArch() == llvm::Triple::mips64el;
   bool IsAArch64 = TargetTriple.getArch() == llvm::Triple::aarch64;
   bool IsWindows = TargetTriple.isOSWindows();
+  bool IsFuchsia = TargetTriple.isOSFuchsia();
 
   ShadowMapping Mapping;
 
@@ -414,7 +415,11 @@ static ShadowMapping getShadowMapping(Tr
     else
       Mapping.Offset = kDefaultShadowOffset32;
   } else {  // LongSize == 64
-    if (IsPPC64)
+    // Fuchsia is always PIE, which means that the beginning of the address
+    // space is always available.
+    if (IsFuchsia)
+      Mapping.Offset = 0;
+    else if (IsPPC64)
       Mapping.Offset = kPPC64_ShadowOffset64;
     else if (IsSystemZ)
       Mapping.Offset = kSystemZ_ShadowOffset64;