1
0
mirror of https://github.com/RPCS3/llvm-mirror.git synced 2024-11-23 11:13:28 +01:00
llvm-mirror/lib/Support/Mutex.cpp
Reid Kleckner 7b2e05b496 [Support] - Add bad alloc error handler for handling allocation malfunctions
Summary:
Patch by Klaus Kretzschmar

We would like to introduce a new type of llvm error handler for handling
bad alloc fault situations.  LLVM already provides a fatal error handler
for serious non-recoverable error situations which by default writes
some error information to stderr and calls exit(1) at the end (functions
are marked as 'noreturn').

For long running processes (e.g. a server application), exiting the
process is not an acceptable option, especially not when the system is
in a temporary resource bottleneck with a good chance to recover from
this fault situation. In such a situation you would rather throw an
exception to stop the current compilation and try to overcome the
resource bottleneck. The user should be aware of the problem of throwing
an exception in bad alloc situations, e.g. you must not do any
allocations in the unwind chain. This is especially true when adding
exceptions in existing unfamiliar code (as already stated in the comment
of the current fatal error handler)

So the new handler can also be used to distinguish from general fatal
error situations where recovering is no option.  It should be used in
cases where a clean unwind after the allocation is guaranteed.

This patch contains:
- A report_bad_alloc function which calls a user defined bad alloc
  error handler. If no user handler is registered the
  report_fatal_error function is called. This function is not marked as
  'noreturn'.
- A install/restore_bad_alloc_error_handler to install/restore the bad
  alloc handler.
- An example (in Mutex.cpp) where the report_bad_alloc function is
  called in case of a malloc returns a nullptr.

If this patch gets accepted we would create similar patches to fix
corresponding malloc/calloc usages in the llvm code.

Reviewers: chandlerc, greened, baldrick, rnk

Reviewed By: rnk

Subscribers: llvm-commits, MatzeB

Differential Revision: https://reviews.llvm.org/D34753

llvm-svn: 307673
2017-07-11 16:45:30 +00:00

128 lines
3.3 KiB
C++

//===- Mutex.cpp - Mutual Exclusion Lock ------------------------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements the llvm::sys::Mutex class.
//
//===----------------------------------------------------------------------===//
#include "llvm/Support/Mutex.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Config/config.h"
//===----------------------------------------------------------------------===//
//=== WARNING: Implementation here must contain only TRULY operating system
//=== independent code.
//===----------------------------------------------------------------------===//
#if !defined(LLVM_ENABLE_THREADS) || LLVM_ENABLE_THREADS == 0
// Define all methods as no-ops if threading is explicitly disabled
namespace llvm {
using namespace sys;
MutexImpl::MutexImpl( bool recursive) { }
MutexImpl::~MutexImpl() { }
bool MutexImpl::acquire() { return true; }
bool MutexImpl::release() { return true; }
bool MutexImpl::tryacquire() { return true; }
}
#else
#if defined(HAVE_PTHREAD_H) && defined(HAVE_PTHREAD_MUTEX_LOCK)
#include <cassert>
#include <pthread.h>
#include <stdlib.h>
namespace llvm {
using namespace sys;
// Construct a Mutex using pthread calls
MutexImpl::MutexImpl( bool recursive)
: data_(nullptr)
{
// Declare the pthread_mutex data structures
pthread_mutex_t* mutex =
static_cast<pthread_mutex_t*>(malloc(sizeof(pthread_mutex_t)));
if (mutex == nullptr)
report_bad_alloc_error("Mutex allocation failed");
pthread_mutexattr_t attr;
// Initialize the mutex attributes
int errorcode = pthread_mutexattr_init(&attr);
assert(errorcode == 0); (void)errorcode;
// Initialize the mutex as a recursive mutex, if requested, or normal
// otherwise.
int kind = ( recursive ? PTHREAD_MUTEX_RECURSIVE : PTHREAD_MUTEX_NORMAL );
errorcode = pthread_mutexattr_settype(&attr, kind);
assert(errorcode == 0);
// Initialize the mutex
errorcode = pthread_mutex_init(mutex, &attr);
assert(errorcode == 0);
// Destroy the attributes
errorcode = pthread_mutexattr_destroy(&attr);
assert(errorcode == 0);
// Assign the data member
data_ = mutex;
}
// Destruct a Mutex
MutexImpl::~MutexImpl()
{
pthread_mutex_t* mutex = static_cast<pthread_mutex_t*>(data_);
assert(mutex != nullptr);
pthread_mutex_destroy(mutex);
free(mutex);
}
bool
MutexImpl::acquire()
{
pthread_mutex_t* mutex = static_cast<pthread_mutex_t*>(data_);
assert(mutex != nullptr);
int errorcode = pthread_mutex_lock(mutex);
return errorcode == 0;
}
bool
MutexImpl::release()
{
pthread_mutex_t* mutex = static_cast<pthread_mutex_t*>(data_);
assert(mutex != nullptr);
int errorcode = pthread_mutex_unlock(mutex);
return errorcode == 0;
}
bool
MutexImpl::tryacquire()
{
pthread_mutex_t* mutex = static_cast<pthread_mutex_t*>(data_);
assert(mutex != nullptr);
int errorcode = pthread_mutex_trylock(mutex);
return errorcode == 0;
}
}
#elif defined(LLVM_ON_UNIX)
#include "Unix/Mutex.inc"
#elif defined( LLVM_ON_WIN32)
#include "Windows/Mutex.inc"
#else
#warning Neither LLVM_ON_UNIX nor LLVM_ON_WIN32 was set in Support/Mutex.cpp
#endif
#endif