1 files changed, 110 insertions, 0 deletions
diff --git a/llvm/lib/Target/AMDGPU/AMDGPUExportKernelRuntimeHandles.cpp b/llvm/lib/Target/AMDGPU/AMDGPUExportKernelRuntimeHandles.cpp
new file mode 100644
index 000000000000..a42d94d56b80
--- /dev/null
+++ b/llvm/lib/Target/AMDGPU/AMDGPUExportKernelRuntimeHandles.cpp
@@ -0,0 +1,110 @@
+//===- AMDGPUExportKernelRuntimeHandles.cpp - Lower enqueued block --------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// \file
+//
+// Give any globals used for OpenCL block enqueue runtime handles external
+// linkage so the runtime may access them. These should behave like internal
+// functions for purposes of linking, but need to have an external symbol in the
+// final object for the runtime to access them.
+//
+// TODO: This could be replaced with a new linkage type or global object
+// metadata that produces an external symbol in the final object, but allows
+// rename on IR linking. Alternatively if we can rely on
+// GlobalValue::getGlobalIdentifier we can just make these external symbols to
+// begin with.
+//
+//===----------------------------------------------------------------------===//
+
+#include "AMDGPUExportKernelRuntimeHandles.h"
+#include "AMDGPU.h"
+#include "llvm/IR/Module.h"
+#include "llvm/Pass.h"
+
+#define DEBUG_TYPE "amdgpu-export-kernel-runtime-handles"
+
+using namespace llvm;
+
+namespace {
+
+/// Lower enqueued blocks.
+class AMDGPUExportKernelRuntimeHandlesLegacy : public ModulePass {
+public:
+  static char ID;
+
+  explicit AMDGPUExportKernelRuntimeHandlesLegacy() : ModulePass(ID) {}
+
+private:
+  bool runOnModule(Module &M) override;
+};
+
+} // end anonymous namespace
+
+char AMDGPUExportKernelRuntimeHandlesLegacy::ID = 0;
+
+char &llvm::AMDGPUExportKernelRuntimeHandlesLegacyID =
+    AMDGPUExportKernelRuntimeHandlesLegacy::ID;
+
+INITIALIZE_PASS(AMDGPUExportKernelRuntimeHandlesLegacy, DEBUG_TYPE,
+                "Externalize enqueued block runtime handles", false, false)
+
+ModulePass *llvm::createAMDGPUExportKernelRuntimeHandlesLegacyPass() {
+  return new AMDGPUExportKernelRuntimeHandlesLegacy();
+}
+
+static bool exportKernelRuntimeHandles(Module &M) {
+  bool Changed = false;
+
+  const StringLiteral HandleSectionName(".amdgpu.kernel.runtime.handle");
+
+  for (GlobalVariable &GV : M.globals()) {
+    if (GV.getSection() == HandleSectionName) {
+      GV.setLinkage(GlobalValue::ExternalLinkage);
+      GV.setDSOLocal(false);
+      Changed = true;
+    }
+  }
+
+  if (!Changed)
+    return false;
+
+  // FIXME: We shouldn't really need to export the kernel address. We can
+  // initialize the runtime handle with the kernel descriptor.
+  for (Function &F : M) {
+    if (F.getCallingConv() != CallingConv::AMDGPU_KERNEL)
+      continue;
+
+    const MDNode *Associated = F.getMetadata(LLVMContext::MD_associated);
+    if (!Associated)
+      continue;
+
+    auto *VM = cast<ValueAsMetadata>(Associated->getOperand(0));
+    auto *Handle = dyn_cast<GlobalObject>(VM->getValue());
+    if (Handle && Handle->getSection() == HandleSectionName) {
+      F.setLinkage(GlobalValue::ExternalLinkage);
+      F.setVisibility(GlobalValue::ProtectedVisibility);
+    }
+  }
+
+  return Changed;
+}
+
+bool AMDGPUExportKernelRuntimeHandlesLegacy::runOnModule(Module &M) {
+  return exportKernelRuntimeHandles(M);
+}
+
+PreservedAnalyses
+AMDGPUExportKernelRuntimeHandlesPass::run(Module &M,
+                                          ModuleAnalysisManager &MAM) {
+  if (!exportKernelRuntimeHandles(M))
+    return PreservedAnalyses::all();
+
+  PreservedAnalyses PA;
+  PA.preserveSet<AllAnalysesOn<Function>>();
+  return PA;
+}