1 files changed, 146 insertions, 0 deletions
diff --git a/llvm/lib/Target/AMDGPU/AMDGPUUnifyMetadata.cpp b/llvm/lib/Target/AMDGPU/AMDGPUUnifyMetadata.cpp
new file mode 100644
index 000000000000..d4401a22a1ad
--- /dev/null
+++ b/llvm/lib/Target/AMDGPU/AMDGPUUnifyMetadata.cpp
@@ -0,0 +1,146 @@
+//===- AMDGPUUnifyMetadata.cpp - Unify OpenCL metadata --------------------===//
+//
+// 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
+// This pass that unifies multiple OpenCL metadata due to linking.
+//
+//===----------------------------------------------------------------------===//
+
+#include "AMDGPU.h"
+#include "llvm/ADT/SmallVector.h"
+#include "llvm/ADT/StringRef.h"
+#include "llvm/IR/Constants.h"
+#include "llvm/IR/Metadata.h"
+#include "llvm/IR/Module.h"
+#include "llvm/Pass.h"
+#include <algorithm>
+#include <cassert>
+
+using namespace llvm;
+
+namespace {
+
+  namespace kOCLMD {
+
+    const char SpirVer[]            = "opencl.spir.version";
+    const char OCLVer[]             = "opencl.ocl.version";
+    const char UsedExt[]            = "opencl.used.extensions";
+    const char UsedOptCoreFeat[]    = "opencl.used.optional.core.features";
+    const char CompilerOptions[]    = "opencl.compiler.options";
+    const char LLVMIdent[]          = "llvm.ident";
+
+  } // end namespace kOCLMD
+
+  /// Unify multiple OpenCL metadata due to linking.
+  class AMDGPUUnifyMetadata : public ModulePass {
+  public:
+    static char ID;
+
+    explicit AMDGPUUnifyMetadata() : ModulePass(ID) {}
+
+  private:
+    bool runOnModule(Module &M) override;
+
+    /// Unify version metadata.
+    /// \return true if changes are made.
+    /// Assume the named metadata has operands each of which is a pair of
+    /// integer constant, e.g.
+    /// !Name = {!n1, !n2}
+    /// !n1 = {i32 1, i32 2}
+    /// !n2 = {i32 2, i32 0}
+    /// Keep the largest version as the sole operand if PickFirst is false.
+    /// Otherwise pick it from the first value, representing kernel module.
+    bool unifyVersionMD(Module &M, StringRef Name, bool PickFirst) {
+      auto NamedMD = M.getNamedMetadata(Name);
+      if (!NamedMD || NamedMD->getNumOperands() <= 1)
+        return false;
+      MDNode *MaxMD = nullptr;
+      auto MaxVer = 0U;
+      for (const auto &VersionMD : NamedMD->operands()) {
+        assert(VersionMD->getNumOperands() == 2);
+        auto CMajor = mdconst::extract<ConstantInt>(VersionMD->getOperand(0));
+        auto VersionMajor = CMajor->getZExtValue();
+        auto CMinor = mdconst::extract<ConstantInt>(VersionMD->getOperand(1));
+        auto VersionMinor = CMinor->getZExtValue();
+        auto Ver = (VersionMajor * 100) + (VersionMinor * 10);
+        if (Ver > MaxVer) {
+          MaxVer = Ver;
+          MaxMD = VersionMD;
+        }
+        if (PickFirst)
+          break;
+      }
+      NamedMD->eraseFromParent();
+      NamedMD = M.getOrInsertNamedMetadata(Name);
+      NamedMD->addOperand(MaxMD);
+      return true;
+    }
+
+  /// Unify version metadata.
+  /// \return true if changes are made.
+  /// Assume the named metadata has operands each of which is a list e.g.
+  /// !Name = {!n1, !n2}
+  /// !n1 = !{!"cl_khr_fp16", {!"cl_khr_fp64"}}
+  /// !n2 = !{!"cl_khr_image"}
+  /// Combine it into a single list with unique operands.
+  bool unifyExtensionMD(Module &M, StringRef Name) {
+    auto NamedMD = M.getNamedMetadata(Name);
+    if (!NamedMD || NamedMD->getNumOperands() == 1)
+      return false;
+
+    SmallVector<Metadata *, 4> All;
+    for (const auto &MD : NamedMD->operands())
+      for (const auto &Op : MD->operands())
+        if (std::find(All.begin(), All.end(), Op.get()) == All.end())
+          All.push_back(Op.get());
+
+    NamedMD->eraseFromParent();
+    NamedMD = M.getOrInsertNamedMetadata(Name);
+    for (const auto &MD : All)
+      NamedMD->addOperand(MDNode::get(M.getContext(), MD));
+
+    return true;
+  }
+};
+
+} // end anonymous namespace
+
+char AMDGPUUnifyMetadata::ID = 0;
+
+char &llvm::AMDGPUUnifyMetadataID = AMDGPUUnifyMetadata::ID;
+
+INITIALIZE_PASS(AMDGPUUnifyMetadata, "amdgpu-unify-metadata",
+                "Unify multiple OpenCL metadata due to linking",
+                false, false)
+
+ModulePass* llvm::createAMDGPUUnifyMetadataPass() {
+  return new AMDGPUUnifyMetadata();
+}
+
+bool AMDGPUUnifyMetadata::runOnModule(Module &M) {
+  const char* Vers[] = {
+      kOCLMD::SpirVer,
+      kOCLMD::OCLVer
+  };
+  const char* Exts[] = {
+      kOCLMD::UsedExt,
+      kOCLMD::UsedOptCoreFeat,
+      kOCLMD::CompilerOptions,
+      kOCLMD::LLVMIdent
+  };
+
+  bool Changed = false;
+
+  for (auto &I : Vers)
+    Changed |= unifyVersionMD(M, I, true);
+
+  for (auto &I : Exts)
+    Changed |= unifyExtensionMD(M, I);
+
+  return Changed;
+}