llvm-project/llvm/lib/Support/Unix/Threading.inc

216 lines
5.8 KiB
C++

//===- Unix/Threading.inc - Unix Threading Implementation ----- -*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file provides the Unix specific implementation of Threading functions.
//
//===----------------------------------------------------------------------===//
#include "llvm/ADT/SmallString.h"
#include "llvm/ADT/Twine.h"
#if defined(__APPLE__)
#include <mach/mach_init.h>
#include <mach/mach_port.h>
#endif
#include <pthread.h>
#if defined(__FreeBSD__)
#include <pthread_np.h> // For pthread_getthreadid_np()
#endif
#if defined(__FreeBSD__) || defined(__FreeBSD_kernel__)
#include <errno.h>
#include <sys/sysctl.h>
#include <sys/user.h>
#include <unistd.h>
#endif
#if defined(__NetBSD__)
#include <lwp.h> // For _lwp_self()
#endif
#if defined(__linux__)
#include <sys/syscall.h> // For syscall codes
#include <unistd.h> // For syscall()
#endif
namespace {
struct ThreadInfo {
void(*UserFn)(void *);
void *UserData;
};
}
static void *ExecuteOnThread_Dispatch(void *Arg) {
ThreadInfo *TI = reinterpret_cast<ThreadInfo*>(Arg);
TI->UserFn(TI->UserData);
return nullptr;
}
void llvm::llvm_execute_on_thread(void(*Fn)(void*), void *UserData,
unsigned RequestedStackSize) {
ThreadInfo Info = { Fn, UserData };
pthread_attr_t Attr;
pthread_t Thread;
// Construct the attributes object.
if (::pthread_attr_init(&Attr) != 0)
return;
// Set the requested stack size, if given.
if (RequestedStackSize != 0) {
if (::pthread_attr_setstacksize(&Attr, RequestedStackSize) != 0)
goto error;
}
// Construct and execute the thread.
if (::pthread_create(&Thread, &Attr, ExecuteOnThread_Dispatch, &Info) != 0)
goto error;
// Wait for the thread and clean up.
::pthread_join(Thread, nullptr);
error:
::pthread_attr_destroy(&Attr);
}
uint64_t llvm::get_threadid() {
#if defined(__APPLE__)
// Calling "mach_thread_self()" bumps the reference count on the thread
// port, so we need to deallocate it. mach_task_self() doesn't bump the ref
// count.
thread_port_t Self = mach_thread_self();
mach_port_deallocate(mach_task_self(), Self);
return Self;
#elif defined(__FreeBSD__)
return uint64_t(pthread_getthreadid_np());
#elif defined(__NetBSD__)
return uint64_t(_lwp_self());
#elif defined(__ANDROID__)
return uint64_t(gettid());
#elif defined(__linux__)
return uint64_t(syscall(SYS_gettid));
#elif defined(LLVM_ON_WIN32)
return uint64_t(::GetCurrentThreadId());
#else
return uint64_t(pthread_self());
#endif
}
static constexpr uint32_t get_max_thread_name_length_impl() {
#if defined(__NetBSD__)
return PTHREAD_MAX_NAMELEN_NP;
#elif defined(__APPLE__)
return 64;
#elif defined(__linux__)
#if HAVE_PTHREAD_SETNAME_NP
return 16;
#else
return 0;
#endif
#elif defined(__FreeBSD__) || defined(__FreeBSD_kernel__)
return 16;
#else
return 0;
#endif
}
uint32_t llvm::get_max_thread_name_length() {
return get_max_thread_name_length_impl();
}
void llvm::set_thread_name(const Twine &Name) {
// Make sure the input is null terminated.
SmallString<64> Storage;
StringRef NameStr = Name.toNullTerminatedStringRef(Storage);
// Truncate from the beginning, not the end, if the specified name is too
// long. For one, this ensures that the resulting string is still null
// terminated, but additionally the end of a long thread name will usually
// be more unique than the beginning, since a common pattern is for similar
// threads to share a common prefix.
if (get_max_thread_name_length() > 0)
NameStr = NameStr.take_back(get_max_thread_name_length());
(void)NameStr;
#if defined(__linux__)
#if (defined(__GLIBC__) && defined(_GNU_SOURCE)) || defined(__ANDROID__)
#if HAVE_PTHREAD_SETNAME_NP
::pthread_setname_np(::pthread_self(), NameStr.data());
#endif
#endif
#elif defined(__FreeBSD__)
::pthread_set_name_np(::pthread_self(), NameStr.data());
#elif defined(__NetBSD__)
::pthread_setname_np(::pthread_self(), "%s",
const_cast<char *>(NameStr.data()));
#elif defined(__APPLE__)
::pthread_setname_np(NameStr.data());
#endif
}
void llvm::get_thread_name(SmallVectorImpl<char> &Name) {
Name.clear();
#if defined(__FreeBSD__) || defined(__FreeBSD_kernel__)
int pid = ::getpid();
uint64_t tid = get_threadid();
struct kinfo_proc *kp = nullptr, *nkp;
size_t len = 0;
int error;
int ctl[4] = { CTL_KERN, KERN_PROC, KERN_PROC_PID | KERN_PROC_INC_THREAD,
(int)pid };
while (1) {
error = sysctl(ctl, 4, kp, &len, nullptr, 0);
if (kp == nullptr || (error != 0 && errno == ENOMEM)) {
// Add extra space in case threads are added before next call.
len += sizeof(*kp) + len / 10;
nkp = (struct kinfo_proc *)realloc(kp, len);
if (nkp == nullptr) {
free(kp);
return;
}
kp = nkp;
continue;
}
if (error != 0)
len = 0;
break;
}
for (size_t i = 0; i < len / sizeof(*kp); i++) {
if (kp[i].ki_tid == (lwpid_t)tid) {
Name.append(kp[i].ki_tdname, kp[i].ki_tdname + strlen(kp[i].ki_tdname));
break;
}
}
free(kp);
return;
#elif defined(__NetBSD__)
constexpr uint32_t len = get_max_thread_name_length_impl();
char buf[len];
::pthread_getname_np(::pthread_self(), buf, len);
Name.append(buf, buf + strlen(buf));
#elif defined(__linux__)
#if (defined(__GLIBC__) && defined(_GNU_SOURCE)) || defined(__ANDROID__)
#if HAVE_PTHREAD_GETNAME_NP
constexpr uint32_t len = get_max_thread_name_length_impl();
char Buffer[len] = {'\0'}; // FIXME: working around MSan false positive.
if (0 == ::pthread_getname_np(::pthread_self(), Buffer, len))
Name.append(Buffer, Buffer + strlen(Buffer));
#endif
#endif
#endif
}