[llvm] [offload][SYCL] Add SYCL Module splitting (PR #119713)

[Maksim Sabianin via llvm-commits]

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+//===-------- SYCLModuleSplitter.cpp - split a module into callgraphs -----===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+// See comments in the header.
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Transforms/Utils/SYCLModuleSplit.h"
+#include "llvm/ADT/SetVector.h"
+#include "llvm/ADT/SmallPtrSet.h"
+#include "llvm/ADT/StringExtras.h"
+#include "llvm/Bitcode/BitcodeWriterPass.h"
+#include "llvm/IR/Constants.h"
+#include "llvm/IR/Function.h"
+#include "llvm/IR/InstIterator.h"
+#include "llvm/IR/Instructions.h"
+#include "llvm/IR/Module.h"
+#include "llvm/IR/PassManager.h"
+#include "llvm/IR/PassManagerImpl.h"
+#include "llvm/IRPrinter/IRPrintingPasses.h"
+#include "llvm/Support/Debug.h"
+#include "llvm/Support/Error.h"
+#include "llvm/Support/FileSystem.h"
+#include "llvm/Support/LineIterator.h"
+#include "llvm/Support/MemoryBuffer.h"
+#include "llvm/Transforms/IPO/GlobalDCE.h"
+#include "llvm/Transforms/IPO/StripDeadPrototypes.h"
+#include "llvm/Transforms/IPO/StripSymbols.h"
+#include "llvm/Transforms/Utils/Cloning.h"
+#include "llvm/Transforms/Utils/SYCLUtils.h"
+
+#include <map>
+#include <utility>
+
+using namespace llvm;
+
+#define DEBUG_TYPE "sycl_module_split"
+
+static bool isKernel(const Function &F) {
+  return F.getCallingConv() == CallingConv::SPIR_KERNEL ||
+         F.getCallingConv() == CallingConv::AMDGPU_KERNEL;
+}
+
+static bool isEntryPoint(const Function &F) {
+  // Skip declarations, if any: they should not be included into a vector of
+  // entry points groups or otherwise we will end up with incorrectly generated
+  // list of symbols.
+  if (F.isDeclaration())
+    return false;
+
+  // Kernels are always considered to be entry points
+  return isKernel(F);
+}
+
+namespace {
+
+// A vector that contains all entry point functions in a split module.
+using EntryPointSet = SetVector<const Function *>;
+
+/// Represents a named group entry points.
+struct EntryPointGroup {
+  std::string GroupName;
+  EntryPointSet Functions;
+
+  EntryPointGroup() = default;
+  EntryPointGroup(const EntryPointGroup &) = default;
+  EntryPointGroup &operator=(const EntryPointGroup &) = default;
+  EntryPointGroup(EntryPointGroup &&) = default;
+  EntryPointGroup &operator=(EntryPointGroup &&) = default;
+
+  EntryPointGroup(StringRef GroupName,
+                  EntryPointSet Functions = EntryPointSet())
+      : GroupName(GroupName), Functions(std::move(Functions)) {}
+
+  void dump() const {
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maksimsab wrote:

Done.

https://github.com/llvm/llvm-project/pull/119713