[clang] [llvm] [HIPSTDPAR] Add support for globals (PR #146813)

[Alex Voicu via llvm-commits]

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@@ -114,24 +115,221 @@ static inline void clearModule(Module &M) { // TODO: simplify.
     eraseFromModule(*M.ifuncs().begin());
 }
 
+static inline SmallVector<std::reference_wrapper<Use>>
+collectIndirectableUses(GlobalVariable *G) {
+  // We are interested only in use chains that end in an Instruction.
+  SmallVector<std::reference_wrapper<Use>> Uses;
+
+  SmallVector<std::reference_wrapper<Use>> Tmp(G->use_begin(), G->use_end());
+  while (!Tmp.empty()) {
+    Use &U = Tmp.back();
+    Tmp.pop_back();
+    if (isa<Instruction>(U.getUser()))
+      Uses.emplace_back(U);
+    else
+      transform(U.getUser()->uses(), std::back_inserter(Tmp),
+                [](auto &&U) { return std::ref(U); });
+  }
+
+  return Uses;
+}
+
+static inline GlobalVariable *getGlobalForName(GlobalVariable *G) {
+  // Create an anonymous global which stores the variable's name, which will be
+  // used by the HIPSTDPAR runtime to look up the program-wide symbol.
+  LLVMContext &Ctx = G->getContext();
+  auto *CDS = ConstantDataArray::getString(Ctx, G->getName());
+
+  GlobalVariable *N = G->getParent()->getOrInsertGlobal("", CDS->getType());
+  N->setInitializer(CDS);
+  N->setLinkage(GlobalValue::LinkageTypes::PrivateLinkage);
+  N->setConstant(true);
+
+  return N;
+}
+
+static inline GlobalVariable *getIndirectionGlobal(Module *M) {
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AlexVlx wrote:

Documentation (these start out as short blocks / sequences taken out from a larger function, or small helpers like `eraseFromModule`). Some are clearly vestigial now, and I should clean the header up.

https://github.com/llvm/llvm-project/pull/146813