[compiler-rt] r194580 - [Sanitizer] Use same PC threshold in slow unwinder on all platforms

[Alexey Samsonov]

Author: samsonov
Date: Wed Nov 13 09:20:10 2013
New Revision: 194580

URL: http://llvm.org/viewvc/llvm-project?rev=194580&view=rev
Log:
[Sanitizer] Use same PC threshold in slow unwinder on all platforms

Modified:
    compiler-rt/trunk/lib/sanitizer_common/sanitizer_linux_libcdep.cc
    compiler-rt/trunk/lib/sanitizer_common/sanitizer_stacktrace.cc
    compiler-rt/trunk/lib/sanitizer_common/sanitizer_stacktrace.h

Modified: compiler-rt/trunk/lib/sanitizer_common/sanitizer_linux_libcdep.cc
URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/sanitizer_common/sanitizer_linux_libcdep.cc?rev=194580&r1=194579&r2=194580&view=diff
==============================================================================
--- compiler-rt/trunk/lib/sanitizer_common/sanitizer_linux_libcdep.cc (original)
+++ compiler-rt/trunk/lib/sanitizer_common/sanitizer_linux_libcdep.cc Wed Nov 13 09:20:10 2013
@@ -161,7 +161,7 @@ void StackTrace::SlowUnwindStack(uptr pc
   UnwindTraceArg arg = {this, Min(max_depth + 1, kStackTraceMax)};
   _Unwind_Backtrace(Unwind_Trace, &arg);
   // We need to pop a few frames so that pc is on top.
-  uptr to_pop = LocatePcInTrace(pc, 64, 6);
+  uptr to_pop = LocatePcInTrace(pc, 6);
   // trace[0] belongs to the current function so we always pop it.
   if (to_pop == 0)
     to_pop = 1;

Modified: compiler-rt/trunk/lib/sanitizer_common/sanitizer_stacktrace.cc
URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/sanitizer_common/sanitizer_stacktrace.cc?rev=194580&r1=194579&r2=194580&view=diff
==============================================================================
--- compiler-rt/trunk/lib/sanitizer_common/sanitizer_stacktrace.cc (original)
+++ compiler-rt/trunk/lib/sanitizer_common/sanitizer_stacktrace.cc Wed Nov 13 09:20:10 2013
@@ -152,9 +152,12 @@ static bool MatchPc(uptr cur_pc, uptr tr
 }
 
 uptr
-StackTrace::LocatePcInTrace(uptr pc, uptr pc_threshold, uptr max_pc_depth) {
+StackTrace::LocatePcInTrace(uptr pc, uptr max_pc_depth) {
+  // Use threshold to find PC in stack trace, as PC we want to unwind from may
+  // slightly differ from return address in the actual unwinded stack trace.
+  const int kPcThreshold = 64;
   for (uptr i = 0; i < max_pc_depth && i < size; ++i) {
-    if (MatchPc(pc, trace[i], pc_threshold))
+    if (MatchPc(pc, trace[i], kPcThreshold))
       return i;
   }
   return 0;

Modified: compiler-rt/trunk/lib/sanitizer_common/sanitizer_stacktrace.h
URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/sanitizer_common/sanitizer_stacktrace.h?rev=194580&r1=194579&r2=194580&view=diff
==============================================================================
--- compiler-rt/trunk/lib/sanitizer_common/sanitizer_stacktrace.h (original)
+++ compiler-rt/trunk/lib/sanitizer_common/sanitizer_stacktrace.h Wed Nov 13 09:20:10 2013
@@ -69,7 +69,7 @@ struct StackTrace {
                        uptr max_depth);
   void SlowUnwindStack(uptr pc, uptr max_depth);
   void PopStackFrames(uptr count);
-  uptr LocatePcInTrace(uptr pc, uptr pc_threshold = 0, uptr max_pc_depth = -1);
+  uptr LocatePcInTrace(uptr pc, uptr max_pc_depth = -1);
 };
 
 }  // namespace __sanitizer