PrettyStackTraceHead is a LLVM_THREAD_LOCAL, which means it's just a global
in LLVM_ENABLE_THREADS=NO builds. If a CrashRecoveryContext is used with
code that uses PrettyStackEntries, and a crash happens, PrettyStackTraceHead is
currently not reset to its pre-crash value. These functions make it possible
to add a cleanup to such code that does this.
(Not reseting the value then causes the assert in ~PrettyStackTraceEntry() to
fire if the code outside of the CrashRecoveryContext also uses
PrettyStackEntries -- for example, clang when building a module.)
Part of PR11974.
llvm-svn: 244338
stack traces by default if you use PrettyStackTraceProgram, so that existing LLVM-based
tools will continue to get it without any changes.
llvm-svn: 193971
