Index: include/llvm-c/Core.h =================================================================== --- include/llvm-c/Core.h +++ include/llvm-c/Core.h @@ -2848,16 +2848,13 @@ * @{ */ -/** Allocate and initialize structures needed to make LLVM safe for - multithreading. The return value indicates whether multithreaded - initialization succeeded. Must be executed in isolation from all - other LLVM api calls. - @see llvm::llvm_start_multithreaded */ +/** Deprecated: Multi-threading can only be enabled/disabled with the compile + time define LLVM_ENABLE_THREADS. This function always returns + LLVMIsMultithreaded(). */ LLVMBool LLVMStartMultithreaded(void); -/** Deallocate structures necessary to make LLVM safe for multithreading. - Must be executed in isolation from all other LLVM api calls. - @see llvm::llvm_stop_multithreaded */ +/** Deprecated: Multi-threading can only be enabled/disabled with the compile + time define LLVM_ENABLE_THREADS. */ void LLVMStopMultithreaded(void); /** Check whether LLVM is executing in thread-safe mode or not. Index: include/llvm/Support/ErrorHandling.h =================================================================== --- include/llvm/Support/ErrorHandling.h +++ include/llvm/Support/ErrorHandling.h @@ -30,9 +30,6 @@ /// install_fatal_error_handler - Installs a new error handler to be used /// whenever a serious (non-recoverable) error is encountered by LLVM. /// - /// If you are using llvm_start_multithreaded, you should register the handler - /// before doing that. - /// /// If no error handler is installed the default is to print the error message /// to stderr, and call exit(1). If an error handler is installed then it is /// the handler's responsibility to log the message, it will no longer be @@ -50,8 +47,6 @@ void *user_data = nullptr); /// Restores default error handling behaviour. - /// This must not be called between llvm_start_multithreaded() and - /// llvm_stop_multithreaded(). void remove_fatal_error_handler(); /// ScopedFatalErrorHandler - This is a simple helper class which just Index: include/llvm/Support/ManagedStatic.h =================================================================== --- include/llvm/Support/ManagedStatic.h +++ include/llvm/Support/ManagedStatic.h @@ -103,9 +103,6 @@ /// llvm_shutdown() when it is destroyed. struct llvm_shutdown_obj { llvm_shutdown_obj() { } - explicit llvm_shutdown_obj(bool multithreaded) { - if (multithreaded) llvm_start_multithreaded(); - } ~llvm_shutdown_obj() { llvm_shutdown(); } }; Index: include/llvm/Support/Mutex.h =================================================================== --- include/llvm/Support/Mutex.h +++ include/llvm/Support/Mutex.h @@ -15,11 +15,13 @@ #define LLVM_SUPPORT_MUTEX_H #include "llvm/Support/Compiler.h" -#include "llvm/Support/Threading.h" #include namespace llvm { + // Forward declare. + bool llvm_is_multithreaded(); + namespace sys { /// @brief Platform agnostic Mutex class. Index: include/llvm/Support/Threading.h =================================================================== --- include/llvm/Support/Threading.h +++ include/llvm/Support/Threading.h @@ -7,40 +7,25 @@ // //===----------------------------------------------------------------------===// // -// TThis file defines llvm_start_multithreaded() and friends. +// This file defines helper functions for running LLVM in a multi-threaded +// environment. // //===----------------------------------------------------------------------===// #ifndef LLVM_SUPPORT_THREADING_H #define LLVM_SUPPORT_THREADING_H +#include "llvm/Support/Mutex.h" + namespace llvm { - /// llvm_start_multithreaded - Allocate and initialize structures needed to - /// make LLVM safe for multithreading. The return value indicates whether - /// multithreaded initialization succeeded. LLVM will still be operational - /// on "failed" return, and will still be safe for hosting threading - /// applications in the JIT, but will not be safe for concurrent calls to the - /// LLVM APIs. - /// THIS MUST EXECUTE IN ISOLATION FROM ALL OTHER LLVM API CALLS. - bool llvm_start_multithreaded(); - /// llvm_stop_multithreaded - Deallocate structures necessary to make LLVM - /// safe for multithreading. - /// THIS MUST EXECUTE IN ISOLATION FROM ALL OTHER LLVM API CALLS. - void llvm_stop_multithreaded(); + /// llvm_get_global_lock() - returns the llvm global lock object. + sys::Mutex &llvm_get_global_lock(); - /// llvm_is_multithreaded - Check whether LLVM is executing in thread-safe - /// mode or not. + /// llvm_is_multithreaded() - returns true if LLVM is compiled with support + /// for multiple threads, and false otherwise. bool llvm_is_multithreaded(); - /// acquire_global_lock - Acquire the global lock. This is a no-op if called - /// before llvm_start_multithreaded(). - void llvm_acquire_global_lock(); - - /// release_global_lock - Release the global lock. This is a no-op if called - /// before llvm_start_multithreaded(). - void llvm_release_global_lock(); - /// llvm_execute_on_thread - Execute the given \p UserFn on a separate /// thread, passing it the provided \p UserData. /// Index: lib/IR/Core.cpp =================================================================== --- lib/IR/Core.cpp +++ lib/IR/Core.cpp @@ -2702,11 +2702,10 @@ /*===-- Threading ------------------------------------------------------===*/ LLVMBool LLVMStartMultithreaded() { - return llvm_start_multithreaded(); + return LLVMIsMultithreaded(); } void LLVMStopMultithreaded() { - llvm_stop_multithreaded(); } LLVMBool LLVMIsMultithreaded() { Index: lib/Support/ErrorHandling.cpp =================================================================== --- lib/Support/ErrorHandling.cpp +++ 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 @@ -37,16 +39,18 @@ 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; } @@ -63,8 +67,20 @@ } 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; + { + // The LLVM error handler is likely to call exit(), which should not be done + // under a mutex (some mutex implementations exhibit undefined behavior if + // destroyed while acquired). So the mutex is acquired only while reading + // the error handler. + 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 Index: lib/Support/ManagedStatic.cpp =================================================================== --- lib/Support/ManagedStatic.cpp +++ lib/Support/ManagedStatic.cpp @@ -14,6 +14,7 @@ #include "llvm/Support/ManagedStatic.h" #include "llvm/Config/config.h" #include "llvm/Support/Atomic.h" +#include "llvm/Support/MutexGuard.h" #include using namespace llvm; @@ -23,7 +24,7 @@ void (*Deleter)(void*)) const { assert(Creator); if (llvm_is_multithreaded()) { - llvm_acquire_global_lock(); + llvm::MutexGuard Lock(llvm_get_global_lock()); if (!Ptr) { void* tmp = Creator(); @@ -44,7 +45,6 @@ StaticList = this; } - llvm_release_global_lock(); } else { assert(!Ptr && !DeleterFn && !Next && "Partially initialized ManagedStatic!?"); @@ -77,6 +77,4 @@ void llvm::llvm_shutdown() { while (StaticList) StaticList->destroy(); - - if (llvm_is_multithreaded()) llvm_stop_multithreaded(); } Index: lib/Support/Threading.cpp =================================================================== --- lib/Support/Threading.cpp +++ lib/Support/Threading.cpp @@ -7,7 +7,8 @@ // //===----------------------------------------------------------------------===// // -// This file implements llvm_start_multithreaded() and friends. +// This file implements helper functions for running LLVM in a multi-threaded +// environment. // //===----------------------------------------------------------------------===// @@ -19,50 +20,19 @@ using namespace llvm; -static bool multithreaded_mode = false; - -static sys::Mutex* global_lock = nullptr; +sys::Mutex& llvm::llvm_get_global_lock() { + static sys::Mutex global_lock; + return global_lock; +} -bool llvm::llvm_start_multithreaded() { +bool llvm::llvm_is_multithreaded() { #if LLVM_ENABLE_THREADS != 0 - assert(!multithreaded_mode && "Already multithreaded!"); - multithreaded_mode = true; - global_lock = new sys::Mutex(true); - - // We fence here to ensure that all initialization is complete BEFORE we - // return from llvm_start_multithreaded(). - sys::MemoryFence(); return true; #else return false; #endif } -void llvm::llvm_stop_multithreaded() { -#if LLVM_ENABLE_THREADS != 0 - assert(multithreaded_mode && "Not currently multithreaded!"); - - // We fence here to insure that all threaded operations are complete BEFORE we - // return from llvm_stop_multithreaded(). - sys::MemoryFence(); - - multithreaded_mode = false; - delete global_lock; -#endif -} - -bool llvm::llvm_is_multithreaded() { - return multithreaded_mode; -} - -void llvm::llvm_acquire_global_lock() { - if (multithreaded_mode) global_lock->acquire(); -} - -void llvm::llvm_release_global_lock() { - if (multithreaded_mode) global_lock->release(); -} - #if LLVM_ENABLE_THREADS != 0 && defined(HAVE_PTHREAD_H) #include Index: lib/Support/Timer.cpp =================================================================== --- lib/Support/Timer.cpp +++ lib/Support/Timer.cpp @@ -18,7 +18,7 @@ #include "llvm/Support/FileSystem.h" #include "llvm/Support/Format.h" #include "llvm/Support/ManagedStatic.h" -#include "llvm/Support/Mutex.h" +#include "llvm/Support/MutexGuard.h" #include "llvm/Support/Process.h" #include "llvm/Support/raw_ostream.h" using namespace llvm; @@ -84,14 +84,13 @@ sys::MemoryFence(); if (tmp) return tmp; - llvm_acquire_global_lock(); + llvm::MutexGuard Lock(llvm::llvm_get_global_lock()); tmp = DefaultTimerGroup; if (!tmp) { tmp = new TimerGroup("Miscellaneous Ungrouped Timers"); sys::MemoryFence(); DefaultTimerGroup = tmp; } - llvm_release_global_lock(); return tmp; } Index: unittests/Support/ManagedStatic.cpp =================================================================== --- unittests/Support/ManagedStatic.cpp +++ unittests/Support/ManagedStatic.cpp @@ -47,7 +47,6 @@ void *p1 = test1::allocate_stack(a1); void *p2 = test1::allocate_stack(a2); - llvm_start_multithreaded(); pthread_t t1, t2; pthread_create(&t1, &a1, test1::helper, nullptr); pthread_create(&t2, &a2, test1::helper, nullptr); @@ -55,7 +54,6 @@ pthread_join(t2, nullptr); free(p1); free(p2); - llvm_stop_multithreaded(); } #endif