Extend ROCr to surface UUID of GPU devices that suppport

Change-Id: I478db68d69a01578770403fa695f9e6391637573

runtime/hsa-runtime/core/util/flag.h

@@ -72,6 +72,7 @@ class Flag {
     enable_sdma_ = os::GetEnvVar("HSA_ENABLE_SDMA");
 
     visible_gpus_ = os::GetEnvVar("ROCR_VISIBLE_DEVICES");
+    filter_visible_gpus_ = os::IsEnvVarSet("ROCR_VISIBLE_DEVICES");
 
     var = os::GetEnvVar("HSA_RUNNING_UNDER_VALGRIND");
     running_valgrind_ = (var == "1") ? true : false;
@@ -143,6 +144,7 @@ class Flag {
   std::string enable_sdma() const { return enable_sdma_; }
 
   std::string visible_gpus() const { return visible_gpus_; }
+  bool filter_visible_gpus() const { return filter_visible_gpus_; }
 
   uint32_t max_queues() const { return max_queues_; }
 
@@ -167,6 +169,7 @@ class Flag {
 
   std::string enable_sdma_;
 
+  bool filter_visible_gpus_;
   std::string visible_gpus_;
 
   uint32_t max_queues_;

runtime/hsa-runtime/core/util/lnx/os_linux.cpp

@@ -237,6 +237,12 @@ bool WaitForAllThreads(Thread* threads, uint threadCount) {
   return true;
 }
 
+bool IsEnvVarSet(std::string env_var_name) {
+  char* buff = NULL;
+  buff = getenv(env_var_name.c_str());
+  return (buff != NULL);
+}
+
 void SetEnvVar(std::string env_var_name, std::string env_var_value) {
   setenv(env_var_name.c_str(), env_var_value.c_str(), 1);
 }

runtime/hsa-runtime/core/util/os.h

@@ -152,6 +152,12 @@ bool WaitForThread(Thread thread);
 /// @return: bool.
 bool WaitForAllThreads(Thread* threads, uint thread_count);
 
+/// @brief: Determines if environment key is set.
+/// @param: env_var_name(Input), name of the environment value.
+/// @return: bool, true for binding any value to environment key,
+/// including an empty string. False otherwise
+bool IsEnvVarSet(std::string env_var_name);
+
 /// @brief: Sets the environment value.
 /// @param: env_var_name(Input), name of the environment value.
 /// @param: env_var_value(Input), value of the environment value.s