From b7d6fc7dba2a69a1797a15e10e9a7521e018acb2 Mon Sep 17 00:00:00 2001
From: Wenzel Jakob <wenzel@cs.cornell.edu>
Date: Sun, 30 Sep 2012 22:46:12 -0400
Subject: [PATCH] omp_get_max_threads still occasionally causes crashes even in
 binaries compiled with icl.. committing a workaround

---
 include/mitsuba/core/thread.h        |  3 +++
 src/integrators/photonmapper/bre.cpp |  2 +-
 src/libcore/thread.cpp               | 21 ++++++++++++++++++---
 src/subsurface/bluenoise.cpp         |  2 +-
 4 files changed, 23 insertions(+), 5 deletions(-)

diff --git a/include/mitsuba/core/thread.h b/include/mitsuba/core/thread.h
index 3157ef6f..136fcfa4 100644
--- a/include/mitsuba/core/thread.h
+++ b/include/mitsuba/core/thread.h
@@ -174,6 +174,9 @@ private:
 	boost::scoped_ptr<ThreadPrivate> d;
 };
 
+/// Variant of \c omp_get_max_threads that works on all platforms
+extern MTS_EXPORT_CORE int mts_omp_get_max_threads();
+
 MTS_NAMESPACE_END
 
 #endif /* __MITSUBA_CORE_THREAD_H_ */
diff --git a/src/integrators/photonmapper/bre.cpp b/src/integrators/photonmapper/bre.cpp
index 7eef2865..de9b3e5f 100644
--- a/src/integrators/photonmapper/bre.cpp
+++ b/src/integrators/photonmapper/bre.cpp
@@ -43,7 +43,7 @@ BeamRadianceEstimator::BeamRadianceEstimator(const PhotonMap *pmap, size_t looku
 
 	Log(EInfo, "Computing photon radii ..");
 	#if defined(MTS_OPENMP)
-		int tcount = omp_get_max_threads();
+		int tcount = mts_omp_get_max_threads();
 	#else
 		int tcount = 1;
 	#endif
diff --git a/src/libcore/thread.cpp b/src/libcore/thread.cpp
index 5fbe4860..5caa52ad 100644
--- a/src/libcore/thread.cpp
+++ b/src/libcore/thread.cpp
@@ -390,9 +390,26 @@ std::string Thread::toString() const {
 	return oss.str();
 }
 
+#if defined(MTS_OPENMP)
+static int __omp_threadCount = 0;
+#endif
+static std::vector<Thread *> __unmanagedThreads;
+static boost::mutex __unmanagedMutex;
+
+#if defined(MTS_OPENMP)
+int mts_omp_get_max_threads() {
+	/* This function exists to sidestep an annoying
+	   implementation bug that causes crashes on OSX */
+	return __omp_threadCount;
+}
+#endif
+
 void Thread::staticInitialization() {
 #if defined(__OSX__)
 	__mts_autorelease_init();
+#endif
+#if defined(MTS_OPENMP)
+	__omp_threadCount = omp_get_max_threads();
 #endif
 	detail::initializeGlobalTLS();
 	detail::initializeLocalTLS();
@@ -405,9 +422,6 @@ void Thread::staticInitialization() {
 	ThreadPrivate::self->set(mainThread);
 }
 
-static std::vector<Thread *> __unmanagedThreads;
-static boost::mutex __unmanagedMutex;
-
 Thread *Thread::registerUnmanagedThread(const std::string &name) {
 	Thread *thread = getThread();
 	if (!thread) {
@@ -443,6 +457,7 @@ void Thread::initializeOpenMP(size_t threadCount) {
 	ref<Logger> logger = Thread::getThread()->getLogger();
 	ref<FileResolver> fResolver = Thread::getThread()->getFileResolver();
 
+	__omp_threadCount = threadCount;
 	omp_set_num_threads((int) threadCount);
 	omp_set_dynamic(false);
 
diff --git a/src/subsurface/bluenoise.cpp b/src/subsurface/bluenoise.cpp
index 8c7499f9..20aecbb3 100644
--- a/src/subsurface/bluenoise.cpp
+++ b/src/subsurface/bluenoise.cpp
@@ -68,7 +68,7 @@ void blueNoisePointSet(const Scene *scene, const std::vector<Shape *> &shapes,
 	int kmax = 8; /* Perform 8 trial runs */
 
 	#if defined(MTS_OPENMP)
-		int nproc = omp_get_max_threads();
+		int nproc = mts_omp_get_max_threads();
 	#else
 		int nproc = 1;
 	#endif