Introduce the use_sigaltstack flag (off by default), which enables using alternate
per-thread stacks for signal handling. This allows to print more verbose error reports
for stack overflows.



git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@154092 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/asan/asan_internal.h b/lib/asan/asan_internal.h
index 6f03d67..39d3adf 100644
--- a/lib/asan/asan_internal.h
+++ b/lib/asan/asan_internal.h
@@ -181,6 +181,8 @@
 int AsanClose(int fd);
 
 bool AsanInterceptsSignal(int signum);
+void SetAlternateSignalStack();
+void UnsetAlternateSignalStack();
 void InstallSignalHandlers();
 int GetPid();
 uintptr_t GetThreadSelf();
@@ -249,6 +251,7 @@
 extern bool   FLAG_allow_user_poisoning;
 extern int    FLAG_sleep_before_dying;
 extern bool   FLAG_handle_segv;
+extern bool   FLAG_use_sigaltstack;
 
 extern int asan_inited;
 // Used to avoid infinite recursion in __asan_init().