[Openmp-commits] [PATCH] D142249: [openmp] Workaround for HSA in issue 60119

[Jon Chesterfield via Phabricator via Openmp-commits]

JonChesterfield updated this revision to Diff 490989.
JonChesterfield added a comment.

- clean up


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D142249/new/

https://reviews.llvm.org/D142249

Files:
  openmp/libomptarget/include/device.h
  openmp/libomptarget/src/interface.cpp
  openmp/libomptarget/src/rtl.cpp


Index: openmp/libomptarget/src/rtl.cpp
===================================================================
--- openmp/libomptarget/src/rtl.cpp
+++ openmp/libomptarget/src/rtl.cpp
@@ -39,11 +39,16 @@
     /* Remote target        */ "libomptarget.rtl.rpc",
 };
 
-PluginManager *PM;
+PluginManager *PM = nullptr;
 
 static char *ProfileTraceFile = nullptr;
 
 __attribute__((constructor(101))) void init() {
+  if (PM != nullptr) {
+    // In case one of the plugins chooses to call back into this constructor
+    return;
+  }
+
   DP("Init target library!\n");
 
   bool UseEventsForAtomicTransfers = true;
@@ -64,11 +69,15 @@
   // TODO: add a configuration option for time granularity
   if (ProfileTraceFile)
     timeTraceProfilerInitialize(500 /* us */, "libomptarget");
+
+  PM->RTLs.loadRTLs();
+  PM->registerDelayedLibraries();
 }
 
 __attribute__((destructor(101))) void deinit() {
   DP("Deinit target library!\n");
   delete PM;
+  PM = nullptr;
 
   if (ProfileTraceFile) {
     // TODO: add env var for file output
Index: openmp/libomptarget/src/interface.cpp
===================================================================
--- openmp/libomptarget/src/interface.cpp
+++ openmp/libomptarget/src/interface.cpp
@@ -35,7 +35,9 @@
 /// adds a target shared library to the target execution image
 EXTERN void __tgt_register_lib(__tgt_bin_desc *Desc) {
   TIMESCOPE();
-  std::call_once(PM->RTLs.InitFlag, &RTLsTy::loadRTLs, &PM->RTLs);
+  if (PM->maybeDelayRegisterLib(Desc)) {
+    return;
+  }
   for (auto &RTL : PM->RTLs.AllRTLs) {
     if (RTL.register_lib) {
       if ((*RTL.register_lib)(Desc) != OFFLOAD_SUCCESS) {
Index: openmp/libomptarget/include/device.h
===================================================================
--- openmp/libomptarget/include/device.h
+++ openmp/libomptarget/include/device.h
@@ -22,6 +22,7 @@
 #include <mutex>
 #include <set>
 #include <thread>
+#include <atomic>
 
 #include "ExclusiveAccess.h"
 #include "omptarget.h"
@@ -530,6 +531,33 @@
   /// Flag to indicate if we use events to ensure the atomicity of
   /// map clauses or not. Can be modified with an environment variable.
   const bool UseEventsForAtomicTransfers;
+
+  // Work around for plugins that call dlopen on shared libraries that call
+  // tgt_register_lib during their initialisation. Stash the pointers in a
+  // vector until the plugins are all initialised and then register them.
+
+  bool maybeDelayRegisterLib(__tgt_bin_desc *Desc) {
+    if (!RTLsLoaded) {
+      // Only reachable from libomptarget constructor
+      DelayedBinDesc.push_back(Desc);
+      return true;
+    } else {
+      return false;
+    }
+  }
+
+  void registerDelayedLibraries() {
+    // Only called from libomptarget constructor, i.e. from one thread
+    for (auto *Desc : DelayedBinDesc) {
+      __tgt_register_lib(Desc);
+    }
+    DelayedBinDesc.clear();
+    RTLsLoaded = true;
+  }
+
+private:
+  std::atomic_bool RTLsLoaded = false;
+  llvm::SmallVector<__tgt_bin_desc *> DelayedBinDesc;
 };
 
 extern PluginManager *PM;


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