[asan] Add a magic shadow value for shadw gap

This gives us something to insert into the shadow gap for systems that
don't have memory protection turned on there (i.e. on Myriad).

Differential Revision: https://reviews.llvm.org/D46457

llvm-svn: 332557

2 files changed, 4 insertions, 0 deletions

diff --git a/compiler-rt/lib/asan/asan_errors.cc b/compiler-rt/lib/asan/asan_errors.cc
index 02e243b127c..bd007e5c563 100644
--- a/compiler-rt/lib/asan/asan_errors.cc
+++ b/compiler-rt/lib/asan/asan_errors.cc
@@ -514,6 +514,7 @@ static void PrintLegend(InternalScopedString *str) {
   PrintShadowByte(str, "  ASan internal:           ", kAsanInternalHeapMagic);
   PrintShadowByte(str, "  Left alloca redzone:     ", kAsanAllocaLeftMagic);
   PrintShadowByte(str, "  Right alloca redzone:    ", kAsanAllocaRightMagic);
+  PrintShadowByte(str, "  Shadow gap:              ", kAsanShadowGap);
 }
 
 static void PrintShadowBytes(InternalScopedString *str, const char *before,
diff --git a/compiler-rt/lib/asan/asan_internal.h b/compiler-rt/lib/asan/asan_internal.h
index 19133e5291a..4a4635229d0 100644
--- a/compiler-rt/lib/asan/asan_internal.h
+++ b/compiler-rt/lib/asan/asan_internal.h
@@ -147,6 +147,9 @@ const int kAsanArrayCookieMagic = 0xac;
 const int kAsanIntraObjectRedzone = 0xbb;
 const int kAsanAllocaLeftMagic = 0xca;
 const int kAsanAllocaRightMagic = 0xcb;
+// Used to populate the shadow gap for systems without memory
+// protection there (i.e. Myriad).
+const int kAsanShadowGap = 0xcc;
 
 static const uptr kCurrentStackFrameMagic = 0x41B58AB3;
 static const uptr kRetiredStackFrameMagic = 0x45E0360E;