Make the error-handling functions thread-safe.
Prior to this change, error handling functions must be installed
and removed only inside of an llvm_[start/stop]_multithreading
pair. This change allows error handling functions to be installed
any time, and from any thread.
Reviewed by: chandlerc
Differential Revision: http://reviews.llvm.org/D4140
llvm-svn: 210937
diff --git a/llvm/lib/Support/ErrorHandling.cpp b/llvm/lib/Support/ErrorHandling.cpp
index 342c4f0..ae1d64d 100644
--- a/llvm/lib/Support/ErrorHandling.cpp
+++ b/llvm/lib/Support/ErrorHandling.cpp
@@ -19,6 +19,8 @@
#include "llvm/Config/config.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/Signals.h"
+#include "llvm/Support/Mutex.h"
+#include "llvm/Support/MutexGuard.h"
#include "llvm/Support/Threading.h"
#include "llvm/Support/raw_ostream.h"
#include <cassert>
@@ -37,17 +39,20 @@
static fatal_error_handler_t ErrorHandler = nullptr;
static void *ErrorHandlerUserData = nullptr;
+static sys::Mutex ErrorHandlerMutex;
+
void llvm::install_fatal_error_handler(fatal_error_handler_t handler,
void *user_data) {
- assert(!llvm_is_multithreaded() &&
- "Cannot register error handlers after starting multithreaded mode!\n");
+ llvm::MutexGuard Lock(ErrorHandlerMutex);
assert(!ErrorHandler && "Error handler already registered!\n");
ErrorHandler = handler;
ErrorHandlerUserData = user_data;
}
void llvm::remove_fatal_error_handler() {
+ llvm::MutexGuard Lock(ErrorHandlerMutex);
ErrorHandler = nullptr;
+ ErrorHandlerUserData = nullptr;
}
void llvm::report_fatal_error(const char *Reason, bool GenCrashDiag) {
@@ -63,8 +68,18 @@
}
void llvm::report_fatal_error(const Twine &Reason, bool GenCrashDiag) {
- if (ErrorHandler) {
- ErrorHandler(ErrorHandlerUserData, Reason.str(), GenCrashDiag);
+ llvm::fatal_error_handler_t handler = nullptr;
+ void* handlerData = nullptr;
+ {
+ // Only acquire the mutex while reading the handler, so as not to invoke a
+ // user-supplied callback under a lock.
+ llvm::MutexGuard Lock(ErrorHandlerMutex);
+ handler = ErrorHandler;
+ handlerData = ErrorHandlerUserData;
+ }
+
+ if (handler) {
+ handler(handlerData, Reason.str(), GenCrashDiag);
} else {
// Blast the result out to stderr. We don't try hard to make sure this
// succeeds (e.g. handling EINTR) and we can't use errs() here because