Cycles: Fix race condition in shader attribute for real now

Ended up moving lock in the more centralized space since multiple shaders
can access this map.

intern/cycles/render/shader.cpp

@@ -332,6 +332,8 @@ ShaderManager *ShaderManager::create(Scene *scene, int shadingsystem)
 
 uint ShaderManager::get_attribute_id(ustring name)
 {
+	thread_scoped_spin_lock lock(attribute_lock_);
+
 	/* get a unique id for each name, for SVM attribute lookup */
 	AttributeIDMap::iterator it = unique_attribute_id.find(name);
 

intern/cycles/render/shader.h

@@ -202,6 +202,8 @@ protected:
 
 	void get_requested_graph_features(ShaderGraph *graph,
 	                                  DeviceRequestedFeatures *requested_features);
+
+	thread_spin_lock attribute_lock_;
 };
 
 CCL_NAMESPACE_END

intern/cycles/render/svm.cpp

@@ -393,13 +393,11 @@ void SVMCompiler::add_node(const float4& f)
 
 uint SVMCompiler::attribute(ustring name)
 {
-	thread_scoped_spin_lock lock(attribute_lock_);
 	return shader_manager->get_attribute_id(name);
 }
 
 uint SVMCompiler::attribute(AttributeStandard std)
 {
-	thread_scoped_spin_lock lock(attribute_lock_);
 	return shader_manager->get_attribute_id(std);
 }
 

intern/cycles/render/svm.h

@@ -218,8 +218,6 @@ protected:
 	int max_stack_use;
 	uint mix_weight_offset;
 	bool compile_failed;
-
-	thread_spin_lock attribute_lock_;
 };
 
 CCL_NAMESPACE_END