Abstract rwlocks into a class, provide a SRW lock implementation for windows
This requires _WIN32_WINNT >= 0x0600.
If someone wants to spend effort on supporting earlier versions,
one can easily add another fallback implementation based on
critical sections, or try to load SRW lock functions dynamically.
This makes sure that the FDE cache is thread safe on windows.
Differential Revision: https://reviews.llvm.org/D38704
llvm-svn: 316364
Cr-Mirrored-From: sso://chromium.googlesource.com/_direct/external/github.com/llvm/llvm-project
Cr-Mirrored-Commit: ed4a317c556fc5104d71a78b2ae2bb955785759f
diff --git a/src/UnwindCursor.hpp b/src/UnwindCursor.hpp
index 6892f96..ab2f542 100644
--- a/src/UnwindCursor.hpp
+++ b/src/UnwindCursor.hpp
@@ -16,9 +16,6 @@
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
-#ifndef _LIBUNWIND_HAS_NO_THREADS
- #include <pthread.h>
-#endif
#include <unwind.h>
#ifdef __APPLE__
@@ -34,6 +31,7 @@
#include "EHHeaderParser.hpp"
#include "libunwind.h"
#include "Registers.hpp"
+#include "RWMutex.hpp"
#include "Unwind-EHABI.h"
namespace libunwind {
@@ -62,9 +60,7 @@
// These fields are all static to avoid needing an initializer.
// There is only one instance of this class per process.
-#ifndef _LIBUNWIND_HAS_NO_THREADS
- static pthread_rwlock_t _lock;
-#endif
+ static RWMutex _lock;
#ifdef __APPLE__
static void dyldUnloadHook(const struct mach_header *mh, intptr_t slide);
static bool _registeredForDyldUnloads;
@@ -91,10 +87,8 @@
template <typename A>
typename DwarfFDECache<A>::entry DwarfFDECache<A>::_initialBuffer[64];
-#ifndef _LIBUNWIND_HAS_NO_THREADS
template <typename A>
-pthread_rwlock_t DwarfFDECache<A>::_lock = PTHREAD_RWLOCK_INITIALIZER;
-#endif
+RWMutex DwarfFDECache<A>::_lock;
#ifdef __APPLE__
template <typename A>
@@ -104,7 +98,7 @@
template <typename A>
typename A::pint_t DwarfFDECache<A>::findFDE(pint_t mh, pint_t pc) {
pint_t result = 0;
- _LIBUNWIND_LOG_NON_ZERO(::pthread_rwlock_rdlock(&_lock));
+ _LIBUNWIND_LOG_IF_FALSE(_lock.lock_shared());
for (entry *p = _buffer; p < _bufferUsed; ++p) {
if ((mh == p->mh) || (mh == 0)) {
if ((p->ip_start <= pc) && (pc < p->ip_end)) {
@@ -113,7 +107,7 @@
}
}
}
- _LIBUNWIND_LOG_NON_ZERO(::pthread_rwlock_unlock(&_lock));
+ _LIBUNWIND_LOG_IF_FALSE(_lock.unlock_shared());
return result;
}
@@ -121,7 +115,7 @@
void DwarfFDECache<A>::add(pint_t mh, pint_t ip_start, pint_t ip_end,
pint_t fde) {
#if !defined(_LIBUNWIND_NO_HEAP)
- _LIBUNWIND_LOG_NON_ZERO(::pthread_rwlock_wrlock(&_lock));
+ _LIBUNWIND_LOG_IF_FALSE(_lock.lock());
if (_bufferUsed >= _bufferEnd) {
size_t oldSize = (size_t)(_bufferEnd - _buffer);
size_t newSize = oldSize * 4;
@@ -145,13 +139,13 @@
_registeredForDyldUnloads = true;
}
#endif
- _LIBUNWIND_LOG_NON_ZERO(::pthread_rwlock_unlock(&_lock));
+ _LIBUNWIND_LOG_IF_FALSE(_lock.unlock());
#endif
}
template <typename A>
void DwarfFDECache<A>::removeAllIn(pint_t mh) {
- _LIBUNWIND_LOG_NON_ZERO(::pthread_rwlock_wrlock(&_lock));
+ _LIBUNWIND_LOG_IF_FALSE(_lock.lock());
entry *d = _buffer;
for (const entry *s = _buffer; s < _bufferUsed; ++s) {
if (s->mh != mh) {
@@ -161,7 +155,7 @@
}
}
_bufferUsed = d;
- _LIBUNWIND_LOG_NON_ZERO(::pthread_rwlock_unlock(&_lock));
+ _LIBUNWIND_LOG_IF_FALSE(_lock.unlock());
}
#ifdef __APPLE__
@@ -174,11 +168,11 @@
template <typename A>
void DwarfFDECache<A>::iterateCacheEntries(void (*func)(
unw_word_t ip_start, unw_word_t ip_end, unw_word_t fde, unw_word_t mh)) {
- _LIBUNWIND_LOG_NON_ZERO(::pthread_rwlock_wrlock(&_lock));
+ _LIBUNWIND_LOG_IF_FALSE(_lock.lock());
for (entry *p = _buffer; p < _bufferUsed; ++p) {
(*func)(p->ip_start, p->ip_end, p->fde, p->mh);
}
- _LIBUNWIND_LOG_NON_ZERO(::pthread_rwlock_unlock(&_lock));
+ _LIBUNWIND_LOG_IF_FALSE(_lock.unlock());
}
#endif // defined(_LIBUNWIND_SUPPORT_DWARF_UNWIND)