[llvm] r210600 - Remove support for runtime multi-threading.
Zachary Turner
zturner at google.com
Tue Jun 10 16:01:20 PDT 2014
Author: zturner
Date: Tue Jun 10 18:01:20 2014
New Revision: 210600
URL: http://llvm.org/viewvc/llvm-project?rev=210600&view=rev
Log:
Remove support for runtime multi-threading.
This patch removes the functions llvm_start_multithreaded() and
llvm_stop_multithreaded(), and changes llvm_is_multithreaded()
to return a constant value based on the value of the compile-time
definition LLVM_ENABLE_THREADS.
Previously, it was possible to have compile-time support for
threads on, and runtime support for threads off, in which case
certain mutexes were not allocated or ever acquired. Now, if the
build is created with threads enabled, mutexes are always acquired.
A test before/after patch of compiling a very large TU showed no
noticeable performance impact of this change.
Reviewers: rnk
Differential Revision: http://reviews.llvm.org/D4076
Modified:
llvm/trunk/include/llvm-c/Core.h
llvm/trunk/include/llvm/Support/ManagedStatic.h
llvm/trunk/include/llvm/Support/Threading.h
llvm/trunk/lib/IR/Core.cpp
llvm/trunk/lib/Support/ErrorHandling.cpp
llvm/trunk/lib/Support/ManagedStatic.cpp
llvm/trunk/lib/Support/Threading.cpp
llvm/trunk/lib/Support/Timer.cpp
Modified: llvm/trunk/include/llvm-c/Core.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm-c/Core.h?rev=210600&r1=210599&r2=210600&view=diff
==============================================================================
--- llvm/trunk/include/llvm-c/Core.h (original)
+++ llvm/trunk/include/llvm-c/Core.h Tue Jun 10 18:01:20 2014
@@ -2848,16 +2848,13 @@ void LLVMDisposePassManager(LLVMPassMana
* @{
*/
-/** 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.
Modified: llvm/trunk/include/llvm/Support/ManagedStatic.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Support/ManagedStatic.h?rev=210600&r1=210599&r2=210600&view=diff
==============================================================================
--- llvm/trunk/include/llvm/Support/ManagedStatic.h (original)
+++ llvm/trunk/include/llvm/Support/ManagedStatic.h Tue Jun 10 18:01:20 2014
@@ -103,9 +103,6 @@ void llvm_shutdown();
/// 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(); }
};
Modified: llvm/trunk/include/llvm/Support/Threading.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Support/Threading.h?rev=210600&r1=210599&r2=210600&view=diff
==============================================================================
--- llvm/trunk/include/llvm/Support/Threading.h (original)
+++ llvm/trunk/include/llvm/Support/Threading.h Tue Jun 10 18:01:20 2014
@@ -14,32 +14,32 @@
#ifndef LLVM_SUPPORT_THREADING_H
#define LLVM_SUPPORT_THREADING_H
+#include "llvm/Config/llvm-config.h"
+#include "llvm/Support/Compiler.h"
+#include <mutex>
+
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_is_multithreaded - Check whether LLVM is executing in thread-safe
- /// mode or not.
- bool llvm_is_multithreaded();
+#if LLVM_ENABLE_THREADS != 0
+ typedef std::mutex mutex;
+ typedef std::recursive_mutex recursive_mutex;
+#else
+ class null_mutex {
+ public:
+ void lock() { }
+ void unlock() { }
+ bool try_lock() { return true; }
+ };
+ typedef null_mutex mutex;
+ typedef null_mutex recursive_mutex;
+#endif
- /// 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_get_global_lock() - returns the llvm global lock object.
+ llvm::recursive_mutex &llvm_get_global_lock();
+
+ /// llvm_is_multithreaded() - returns true if LLVM is compiled with support
+ /// for multiple threads, and false otherwise.
+ bool llvm_is_multithreaded();
/// llvm_execute_on_thread - Execute the given \p UserFn on a separate
/// thread, passing it the provided \p UserData.
Modified: llvm/trunk/lib/IR/Core.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/IR/Core.cpp?rev=210600&r1=210599&r2=210600&view=diff
==============================================================================
--- llvm/trunk/lib/IR/Core.cpp (original)
+++ llvm/trunk/lib/IR/Core.cpp Tue Jun 10 18:01:20 2014
@@ -2702,11 +2702,10 @@ void LLVMDisposePassManager(LLVMPassMana
/*===-- Threading ------------------------------------------------------===*/
LLVMBool LLVMStartMultithreaded() {
- return llvm_start_multithreaded();
+ return LLVMIsMultithreaded();
}
void LLVMStopMultithreaded() {
- llvm_stop_multithreaded();
}
LLVMBool LLVMIsMultithreaded() {
Modified: llvm/trunk/lib/Support/ErrorHandling.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Support/ErrorHandling.cpp?rev=210600&r1=210599&r2=210600&view=diff
==============================================================================
--- llvm/trunk/lib/Support/ErrorHandling.cpp (original)
+++ llvm/trunk/lib/Support/ErrorHandling.cpp Tue Jun 10 18:01:20 2014
@@ -23,6 +23,7 @@
#include "llvm/Support/raw_ostream.h"
#include <cassert>
#include <cstdlib>
+#include <mutex>
#if defined(HAVE_UNISTD_H)
# include <unistd.h>
@@ -37,16 +38,18 @@ using namespace llvm;
static fatal_error_handler_t ErrorHandler = nullptr;
static void *ErrorHandlerUserData = nullptr;
+static llvm::recursive_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");
+ std::lock_guard<llvm::recursive_mutex> Lock(ErrorHandlerMutex);
assert(!ErrorHandler && "Error handler already registered!\n");
ErrorHandler = handler;
ErrorHandlerUserData = user_data;
}
void llvm::remove_fatal_error_handler() {
+ std::lock_guard<llvm::recursive_mutex> Lock(ErrorHandlerMutex);
ErrorHandler = nullptr;
}
@@ -63,6 +66,7 @@ void llvm::report_fatal_error(StringRef
}
void llvm::report_fatal_error(const Twine &Reason, bool GenCrashDiag) {
+ std::lock_guard<llvm::recursive_mutex> Lock(ErrorHandlerMutex);
if (ErrorHandler) {
ErrorHandler(ErrorHandlerUserData, Reason.str(), GenCrashDiag);
} else {
Modified: llvm/trunk/lib/Support/ManagedStatic.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Support/ManagedStatic.cpp?rev=210600&r1=210599&r2=210600&view=diff
==============================================================================
--- llvm/trunk/lib/Support/ManagedStatic.cpp (original)
+++ llvm/trunk/lib/Support/ManagedStatic.cpp Tue Jun 10 18:01:20 2014
@@ -15,6 +15,7 @@
#include "llvm/Config/config.h"
#include "llvm/Support/Atomic.h"
#include <cassert>
+#include <mutex>
using namespace llvm;
static const ManagedStaticBase *StaticList = nullptr;
@@ -23,7 +24,7 @@ void ManagedStaticBase::RegisterManagedS
void (*Deleter)(void*)) const {
assert(Creator);
if (llvm_is_multithreaded()) {
- llvm_acquire_global_lock();
+ std::lock_guard<llvm::recursive_mutex> Lock(llvm_get_global_lock());
if (!Ptr) {
void* tmp = Creator();
@@ -44,7 +45,6 @@ void ManagedStaticBase::RegisterManagedS
StaticList = this;
}
- llvm_release_global_lock();
} else {
assert(!Ptr && !DeleterFn && !Next &&
"Partially initialized ManagedStatic!?");
@@ -77,6 +77,4 @@ void ManagedStaticBase::destroy() const
void llvm::llvm_shutdown() {
while (StaticList)
StaticList->destroy();
-
- if (llvm_is_multithreaded()) llvm_stop_multithreaded();
}
Modified: llvm/trunk/lib/Support/Threading.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Support/Threading.cpp?rev=210600&r1=210599&r2=210600&view=diff
==============================================================================
--- llvm/trunk/lib/Support/Threading.cpp (original)
+++ llvm/trunk/lib/Support/Threading.cpp Tue Jun 10 18:01:20 2014
@@ -19,50 +19,19 @@
using namespace llvm;
-static bool multithreaded_mode = false;
-
-static sys::Mutex* global_lock = nullptr;
+llvm::recursive_mutex& llvm::llvm_get_global_lock() {
+ static llvm::recursive_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 <pthread.h>
Modified: llvm/trunk/lib/Support/Timer.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Support/Timer.cpp?rev=210600&r1=210599&r2=210600&view=diff
==============================================================================
--- llvm/trunk/lib/Support/Timer.cpp (original)
+++ llvm/trunk/lib/Support/Timer.cpp Tue Jun 10 18:01:20 2014
@@ -84,14 +84,13 @@ static TimerGroup *getDefaultTimerGroup(
sys::MemoryFence();
if (tmp) return tmp;
- llvm_acquire_global_lock();
+ std::lock_guard<llvm::recursive_mutex> 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;
}
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