[compiler-rt] r343638 - [hwasan] Fix top PC in error stack trace being off by 1 instruction.

[Evgeniy Stepanov via llvm-commits]

Author: eugenis
Date: Tue Oct  2 14:52:02 2018
New Revision: 343638

URL: http://llvm.org/viewvc/llvm-project?rev=343638&view=rev
Log:
[hwasan] Fix top PC in error stack trace being off by 1 instruction.

Summary:
GetStackTrace treats top PC as a return address from an error reporting
function, and adjusts it down by 1 instruction. This is not necessary in
a signal handler, so adjust PC up to compensate.

Reviewers: kcc, vitalybuka, jfb

Subscribers: kubamracek, llvm-commits

Differential Revision: https://reviews.llvm.org/D52802

Modified:
    compiler-rt/trunk/lib/hwasan/hwasan_linux.cc

Modified: compiler-rt/trunk/lib/hwasan/hwasan_linux.cc
URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/hwasan/hwasan_linux.cc?rev=343638&r1=343637&r2=343638&view=diff
==============================================================================
--- compiler-rt/trunk/lib/hwasan/hwasan_linux.cc (original)
+++ compiler-rt/trunk/lib/hwasan/hwasan_linux.cc Tue Oct  2 14:52:02 2018
@@ -355,8 +355,8 @@ static bool HwasanOnSIGTRAP(int signo, s
   BufferedStackTrace *stack = stack_buffer.data();
   stack->Reset();
   SignalContext sig{info, uc};
-  GetStackTrace(stack, kStackTraceMax, sig.pc, sig.bp, uc,
-                common_flags()->fast_unwind_on_fatal);
+  GetStackTrace(stack, kStackTraceMax, StackTrace::GetNextInstructionPc(sig.pc),
+                sig.bp, uc, common_flags()->fast_unwind_on_fatal);
 
   ReportTagMismatch(stack, ai.addr, ai.size, ai.is_store);
 
@@ -375,8 +375,8 @@ static bool HwasanOnSIGTRAP(int signo, s
 
 static void OnStackUnwind(const SignalContext &sig, const void *,
                           BufferedStackTrace *stack) {
-  GetStackTrace(stack, kStackTraceMax, sig.pc, sig.bp, sig.context,
-                common_flags()->fast_unwind_on_fatal);
+  GetStackTrace(stack, kStackTraceMax, StackTrace::GetNextInstructionPc(sig.pc),
+                sig.bp, sig.context, common_flags()->fast_unwind_on_fatal);
 }
 
 void HwasanOnDeadlySignal(int signo, void *info, void *context) {