Add NetBSD support in sanitizer_unwind_linux_libcdep.cc

[krytarowski]

Summary

NetBSD is a POSIX-like and BSD-family system.

Reuse FreeBSD and Linux code.

NetBSD uses DWARF ExceptionHandler.

Part of the code inspired by the original work on libsanitizer in GCC 5.4 by Christos Zoulas.

Sponsored by <The NetBSD Foundation>

[vitalybuka]

lib/sanitizer_common/sanitizer_unwind_linux_libcdep.cc

11

Same about commend as in D35553

[krytarowski]

lib/sanitizer_common/sanitizer_unwind_linux_libcdep.cc

11

I'm not sure what does this comment mean. If we can improve it, we can do it later. I will push this change as it is.

There will certainly come OpenBSD at some point and they will reuse the same files.

lib/sanitizer_common/sanitizer_unwind_linux_libcdep.cc

 //===-- sanitizer_unwind_linux_libcdep.cc ---------------------------------===//
 //
 //                     The LLVM Compiler Infrastructure
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 //
 // This file contains the unwind.h-based (aka "slow") stack unwinding routines
-// available to the tools on Linux, Android, and FreeBSD.
+// available to the tools on Linux, Android, NetBSD and FreeBSD.
 //===----------------------------------------------------------------------===//
 
 #include "sanitizer_platform.h"
-#if SANITIZER_FREEBSD || SANITIZER_LINUX
+#if SANITIZER_FREEBSD || SANITIZER_LINUX || SANITIZER_NETBSD
 #include "sanitizer_common.h"
 #include "sanitizer_stacktrace.h"
 
 #if SANITIZER_ANDROID
 #include <dlfcn.h>  // for dlopen()
 #endif
 
 #if SANITIZER_FREEBSD
VReport(1,
             "You may see broken stack traces in SEGV reports.");
     acquire_my_map_info_list = 0;
     unwind_backtrace_signal_arch = 0;
     release_my_map_info_list = 0;
   }
 }
 #endif
 
-#ifdef __arm__
+#if defined(__arm__) && !SANITIZER_NETBSD
+// NetBSD uses dwarf EH
 #define UNWIND_STOP _URC_END_OF_STACK
 #define UNWIND_CONTINUE _URC_NO_REASON
 #else
 #define UNWIND_STOP _URC_NORMAL_STOP
 #define UNWIND_CONTINUE _URC_NO_REASON
 #endif
 
 uptr Unwind_GetIP(struct _Unwind_Context *ctx) {
void BufferedStackTrace::SlowUnwindStackWithContext(uptr pc, void *context,
   // +2 compensate for libcorkscrew unwinder returning addresses of call
   // instructions instead of raw return addresses.
   for (sptr i = 0; i < res; ++i)
     trace_buffer[size++] = frames[i].absolute_pc + 2;
 }
 
 }  // namespace __sanitizer
 
-#endif  // SANITIZER_FREEBSD || SANITIZER_LINUX
+#endif  // SANITIZER_FREEBSD || SANITIZER_LINUX || SANITIZER_NETBSD