[libcxxabi] r208135 - On single threaded systems, turn mutexes into nops
Jonathan Roelofs
jonathan at codesourcery.com
Tue May 6 14:30:56 PDT 2014
Author: jroelofs
Date: Tue May 6 16:30:56 2014
New Revision: 208135
URL: http://llvm.org/viewvc/llvm-project?rev=208135&view=rev
Log:
On single threaded systems, turn mutexes into nops
http://reviews.llvm.org/D3386
Added:
libcxxabi/trunk/src/config.h
Modified:
libcxxabi/trunk/src/cxa_exception.cpp
libcxxabi/trunk/src/cxa_exception_storage.cpp
libcxxabi/trunk/src/cxa_guard.cpp
libcxxabi/trunk/src/fallback_malloc.ipp
libcxxabi/trunk/test/test_exception_storage.cpp
Added: libcxxabi/trunk/src/config.h
URL: http://llvm.org/viewvc/llvm-project/libcxxabi/trunk/src/config.h?rev=208135&view=auto
==============================================================================
--- libcxxabi/trunk/src/config.h (added)
+++ libcxxabi/trunk/src/config.h Tue May 6 16:30:56 2014
@@ -0,0 +1,25 @@
+//===----------------------------- config.h -------------------------------===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is dual licensed under the MIT and the University of Illinois Open
+// Source Licenses. See LICENSE.TXT for details.
+//
+//
+// Defines macros used within the libc++abi project.
+//
+//===----------------------------------------------------------------------===//
+
+
+#ifndef LIBCXXABI_CONFIG_H
+#define LIBCXXABI_CONFIG_H
+
+#include <unistd.h>
+
+#if defined(_POSIX_THREADS) && _POSIX_THREADS > 0
+# define LIBCXXABI_SINGLE_THREADED 0
+#else
+# define LIBCXXABI_SINGLE_THREADED 1
+#endif
+
+#endif // LIBCXXABI_CONFIG_H
Modified: libcxxabi/trunk/src/cxa_exception.cpp
URL: http://llvm.org/viewvc/llvm-project/libcxxabi/trunk/src/cxa_exception.cpp?rev=208135&r1=208134&r2=208135&view=diff
==============================================================================
--- libcxxabi/trunk/src/cxa_exception.cpp (original)
+++ libcxxabi/trunk/src/cxa_exception.cpp Tue May 6 16:30:56 2014
@@ -11,13 +11,15 @@
//
//===----------------------------------------------------------------------===//
+#include "config.h"
#include "cxxabi.h"
#include <exception> // for std::terminate
#include <cstdlib> // for malloc, free
#include <cstring> // for memset
-#include <pthread.h>
-
+#if !LIBCXXABI_SINGLE_THREADED
+# include <pthread.h> // for fallback_malloc.ipp's mutexes
+#endif
#include "cxa_exception.hpp"
#include "cxa_handlers.hpp"
Modified: libcxxabi/trunk/src/cxa_exception_storage.cpp
URL: http://llvm.org/viewvc/llvm-project/libcxxabi/trunk/src/cxa_exception_storage.cpp?rev=208135&r1=208134&r2=208135&view=diff
==============================================================================
--- libcxxabi/trunk/src/cxa_exception_storage.cpp (original)
+++ libcxxabi/trunk/src/cxa_exception_storage.cpp Tue May 6 16:30:56 2014
@@ -13,7 +13,19 @@
#include "cxa_exception.hpp"
-#ifdef HAS_THREAD_LOCAL
+#include "config.h"
+
+#if LIBCXXABI_SINGLE_THREADED
+
+namespace __cxxabiv1 {
+extern "C" {
+ static __cxa_eh_globals eh_globals;
+ __cxa_eh_globals *__cxa_get_globals() { return &eh_globals; }
+ __cxa_eh_globals *__cxa_get_globals_fast() { return &eh_globals; }
+ }
+}
+
+#elif defined(HAS_THREAD_LOCAL)
namespace __cxxabiv1 {
Modified: libcxxabi/trunk/src/cxa_guard.cpp
URL: http://llvm.org/viewvc/llvm-project/libcxxabi/trunk/src/cxa_guard.cpp?rev=208135&r1=208134&r2=208135&view=diff
==============================================================================
--- libcxxabi/trunk/src/cxa_guard.cpp (original)
+++ libcxxabi/trunk/src/cxa_guard.cpp Tue May 6 16:30:56 2014
@@ -8,8 +8,11 @@
//===----------------------------------------------------------------------===//
#include "abort_message.h"
+#include "config.h"
-#include <pthread.h>
+#if !LIBCXXABI_SINGLE_THREADED
+# include <pthread.h>
+#endif
#include <stdint.h>
/*
@@ -59,8 +62,10 @@ void set_initialized(guard_type* guard_o
#endif
+#if !LIBCXXABI_SINGLE_THREADED
pthread_mutex_t guard_mut = PTHREAD_MUTEX_INITIALIZER;
pthread_cond_t guard_cv = PTHREAD_COND_INITIALIZER;
+#endif
#if defined(__APPLE__) && !defined(__arm__)
@@ -161,9 +166,27 @@ set_lock(uint32_t& x, lock_type y)
extern "C"
{
+#if LIBCXXABI_SINGLE_THREADED
+int __cxa_guard_acquire(guard_type* guard_object)
+{
+ return !is_initialized(guard_object);
+}
+
+void __cxa_guard_release(guard_type* guard_object)
+{
+ *guard_object = 0;
+ set_initialized(guard_object);
+}
+
+void __cxa_guard_abort(guard_type* guard_object)
+{
+ *guard_object = 0;
+}
+
+#else // !LIBCXXABI_SINGLE_THREADED
+
int __cxa_guard_acquire(guard_type* guard_object)
{
- char* initialized = (char*)guard_object;
if (pthread_mutex_lock(&guard_mut))
abort_message("__cxa_guard_acquire failed to acquire mutex");
int result = *initialized == 0;
@@ -226,6 +249,8 @@ void __cxa_guard_abort(guard_type* guard
abort_message("__cxa_guard_abort failed to broadcast condition variable");
}
+#endif // !LIBCXXABI_SINGLE_THREADED
+
} // extern "C"
} // __cxxabiv1
Modified: libcxxabi/trunk/src/fallback_malloc.ipp
URL: http://llvm.org/viewvc/llvm-project/libcxxabi/trunk/src/fallback_malloc.ipp?rev=208135&r1=208134&r2=208135&view=diff
==============================================================================
--- libcxxabi/trunk/src/fallback_malloc.ipp (original)
+++ libcxxabi/trunk/src/fallback_malloc.ipp Tue May 6 16:30:56 2014
@@ -11,6 +11,8 @@
//
//===----------------------------------------------------------------------===//
+#include "config.h"
+
// A small, simple heap manager based (loosely) on
// the startup heap manager from FreeBSD, optimized for space.
//
@@ -23,16 +25,28 @@
namespace {
+// When POSIX threads are not available, make the mutex operations a nop
+#if LIBCXXABI_SINGLE_THREADED
+static void * heap_mutex = 0;
+#else
static pthread_mutex_t heap_mutex = PTHREAD_MUTEX_INITIALIZER;
+#endif
class mutexor {
public:
+#if LIBCXXABI_SINGLE_THREADED
+ mutexor ( void * ) {}
+ ~mutexor () {}
+#else
mutexor ( pthread_mutex_t *m ) : mtx_(m) { pthread_mutex_lock ( mtx_ ); }
~mutexor () { pthread_mutex_unlock ( mtx_ ); }
+#endif
private:
mutexor ( const mutexor &rhs );
mutexor & operator = ( const mutexor &rhs );
+#if !LIBCXXABI_SINGLE_THREADED
pthread_mutex_t *mtx_;
+#endif
};
Modified: libcxxabi/trunk/test/test_exception_storage.cpp
URL: http://llvm.org/viewvc/llvm-project/libcxxabi/trunk/test/test_exception_storage.cpp?rev=208135&r1=208134&r2=208135&view=diff
==============================================================================
--- libcxxabi/trunk/test/test_exception_storage.cpp (original)
+++ libcxxabi/trunk/test/test_exception_storage.cpp Tue May 6 16:30:56 2014
@@ -7,10 +7,14 @@
//
//===----------------------------------------------------------------------===//
+#include "../src/config.h"
+
#include <cstdlib>
#include <algorithm>
#include <iostream>
-#include <pthread.h>
+#if !LIBCXXABI_SINGLE_THREADED
+# include <pthread.h>
+#endif
#include <unistd.h>
#include "../src/cxa_exception.hpp"
@@ -34,10 +38,11 @@ void *thread_code (void *parm) {
return parm;
}
-
+#if !LIBCXXABI_SINGLE_THREADED
#define NUMTHREADS 10
size_t thread_globals [ NUMTHREADS ] = { 0 };
pthread_t threads [ NUMTHREADS ];
+#endif
void print_sizes ( size_t *first, size_t *last ) {
std::cout << "{ " << std::hex;
@@ -49,6 +54,10 @@ void print_sizes ( size_t *first, size_t
int main ( int argc, char *argv [] ) {
int retVal = 0;
+#if LIBCXXABI_SINGLE_THREADED
+ size_t thread_globals;
+ retVal = thread_code(&thread_globals) != 0;
+#else
// Make the threads, let them run, and wait for them to finish
for ( int i = 0; i < NUMTHREADS; ++i )
pthread_create( threads + i, NULL, thread_code, (void *) (thread_globals + i));
@@ -69,6 +78,7 @@ int main ( int argc, char *argv [] ) {
retVal = 2;
}
// print_sizes ( thread_globals, thread_globals + NUMTHREADS );
-
+
+#endif
return retVal;
}
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