hwasan: Teach the runtime to identify the local variable being accessed in UAR reports.

Each function's PC is recorded in the ring buffer. From there we can access
the function's local variables and reconstruct the tag of each one with the
help of the information printed by llvm-symbolizer's new FRAME command. We
can then find the variable that was likely being accessed by matching the
pointer's tag against the reconstructed tag.

Differential Revision: https://reviews.llvm.org/D63469

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@364607 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 5 insertions, 3 deletions

diff --git a/lib/hwasan/hwasan.h b/lib/hwasan/hwasan.h
index 9cc9490a9..465e56c3a 100644
--- a/lib/hwasan/hwasan.h
+++ b/lib/hwasan/hwasan.h
@@ -44,6 +44,11 @@ const uptr kAddressTagMask = 0xFFUL << kAddressTagShift;
 // for threads and stack histories. This is an ABI constant.
 const unsigned kShadowBaseAlignment = 32;
 
+const unsigned kRecordAddrBaseTagShift = 3;
+const unsigned kRecordFPShift = 48;
+const unsigned kRecordFPLShift = 4;
+const unsigned kRecordFPModulus = 1 << (64 - kRecordFPShift + kRecordFPLShift);
+
 static inline tag_t GetTagFromPointer(uptr p) {
   return p >> kAddressTagShift;
 }
@@ -93,9 +98,6 @@ void hwasan_free(void *ptr, StackTrace *stack);
 void InstallTrapHandler();
 void InstallAtExitHandler();
 
-const char *GetStackOriginDescr(u32 id, uptr *pc);
-const char *GetStackFrameDescr(uptr pc);
-
 void EnterSymbolizer();
 void ExitSymbolizer();
 bool IsInSymbolizer();