[Openmp-commits] [clang] [llvm] [openmp] [OpenMP] Rework handling of global ctor/dtors in OpenMP (PR #71739)

Joseph Huber via Openmp-commits openmp-commits at lists.llvm.org
Thu Nov 9 04:06:17 PST 2023

@@ -2794,6 +2794,14 @@ void ItaniumCXXABI::registerGlobalDtor(CodeGenFunction &CGF, const VarDecl &D,
   if (D.isNoDestroy(CGM.getContext()))
+  // OpenMP offloading supports C++ constructors and destructors but we do not
+  // always have 'atexit' available. Instead lower these to use the LLVM global
+  // destructors which we can handle directly in the runtime.
+  if (CGM.getLangOpts().OpenMP && CGM.getLangOpts().OpenMPIsTargetDevice &&
+      !D.isStaticLocal() &&
+      (CGM.getTriple().isAMDGPU() || CGM.getTriple().isNVPTX()))
jhuber6 wrote:

Yeah, these types of things are problematic especially if we consider getting SPIR-V support eventually. The logic basically goes like this. OpenMP supports global destructors but does not always support the `atexit` function. The old logic used to replace everything. This now at least lets CPU based targets use regular handling. I could make this unconditional for OpenMP, but I figured it'd be better to allow the CPU based targets to use the regular handling.

More or less this is just a concession to prevent regressions from this patch. The old logic looked like this, which did this unconditionally. Like I said, could remove the AMD and PTX checks and just do this on the CPU as well if it would be better.
  if (CGM.getLangOpts().OMPTargetTriples.empty() &&
    return false;


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