[offload][SYCL] Add SYCL Module splitting.

llvm/include/llvm/Transforms/Utils/SYCLUtils.h

@@ -0,0 +1,101 @@
+//===------------ SYCLUtils.h - SYCL utility functions --------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+// Utility functions for SYCL.
+//===----------------------------------------------------------------------===//
+#ifndef LLVM_FRONTEND_SYCL_UTILS_H
+#define LLVM_FRONTEND_SYCL_UTILS_H
+
+#include "llvm/ADT/DenseMap.h"
+#include "llvm/ADT/Hashing.h"
+#include "llvm/ADT/SmallString.h"
+#include "llvm/ADT/SmallVector.h"
+#include "llvm/ADT/StringRef.h"
+#include "llvm/ADT/Twine.h"
+
+#include <optional>
+#include <string>
+
+namespace llvm {
+
+class Module;
+class Function;
+class raw_ostream;
+
+namespace sycl {
+
+enum class IRSplitMode {
+  IRSM_PER_TU,     // one module per translation unit
+  IRSM_PER_KERNEL, // one module per kernel
+  IRSM_NONE        // no splitting
+};
+
+/// \returns IRSplitMode value if \p S is recognized. Otherwise, std::nullopt is
+/// returned.
+std::optional<IRSplitMode> convertStringToSplitMode(StringRef S);
+
+/// FunctionCategorizer used for splitting in SYCL compilation flow.
+class FunctionCategorizer {
+public:
+  FunctionCategorizer(IRSplitMode SM);
+
+  FunctionCategorizer() = delete;
+  FunctionCategorizer(FunctionCategorizer &) = delete;
+  FunctionCategorizer &operator=(const FunctionCategorizer &) = delete;
+  FunctionCategorizer(FunctionCategorizer &&) = default;
+  FunctionCategorizer &operator=(FunctionCategorizer &&) = default;
+
+  /// Returns integer specifying the category for the entry point.
+  /// If the given function isn't an entry point then returns std::nullopt.
+  std::optional<int> operator()(const Function &F);
+
+private:
+  struct KeyInfo {
+    static SmallString<0> getEmptyKey() { return SmallString<0>(""); }
+
+    static SmallString<0> getTombstoneKey() { return SmallString<0>("-"); }
+
+    static bool isEqual(const SmallString<0> &LHS, const SmallString<0> &RHS) {
+      return LHS == RHS;
+    }
+
+    static unsigned getHashValue(const SmallString<0> &S) {
+      return llvm::hash_value(StringRef(S));
+    }
+  };
+
+  IRSplitMode SM;
+  DenseMap<SmallString<0>, int, KeyInfo> StrKeyToID;
+};
+
+/// The structure represents a LLVM Module accompanied by additional
+/// information. Split Modules are being stored at disk due to the high RAM
+/// consumption during the whole splitting process.
+struct ModuleAndSYCLMetadata {
+  std::string ModuleFilePath;
+  std::string Symbols;
+
+  ModuleAndSYCLMetadata() = delete;
+  ModuleAndSYCLMetadata(const ModuleAndSYCLMetadata &) = default;
+  ModuleAndSYCLMetadata &operator=(const ModuleAndSYCLMetadata &) = default;
+  ModuleAndSYCLMetadata(ModuleAndSYCLMetadata &&) = default;
+  ModuleAndSYCLMetadata &operator=(ModuleAndSYCLMetadata &&) = default;
+
+  ModuleAndSYCLMetadata(const Twine &File, std::string Symbols)
+      : ModuleFilePath(File.str()), Symbols(std::move(Symbols)) {}
+};
+
+std::string makeSymbolTable(const Module &M);
+
+using StringTable = SmallVector<SmallVector<SmallString<64>>>;
+
+void writeStringTable(const StringTable &Table, raw_ostream &OS);
+
+} // namespace sycl
+} // namespace llvm
+
+#endif // LLVM_FRONTEND_SYCL_UTILS_H

llvm/include/llvm/Transforms/Utils/SplitModuleByCategory.h

@@ -0,0 +1,42 @@
+//===-------- SplitModuleByCategory.h - module split ------------*- C++ -*-===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+// Functionality to split a module by categories.
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_FRONTEND_SYCL_SPLIT_MODULE_H
+#define LLVM_FRONTEND_SYCL_SPLIT_MODULE_H
+
+#include "llvm/ADT/STLFunctionalExtras.h"
+
+#include <memory>
+#include <optional>
+#include <string>
+
+namespace llvm {
+
+class Module;
+class Function;
+
+namespace sycl {
+
+/// FunctionCategorizer returns integer category for the given Function.
+/// Otherwise, it returns std::nullopt if function doesn't have a category.
+using FunctionCategorizer = function_ref<std::optional<int>(const Function &F)>;
+
+using PostSplitCallbackType = function_ref<void(std::unique_ptr<Module> Part)>;
+
+/// Splits the given module \p M.
+/// Every split image is being passed to \p Callback for further possible
+/// processing.
+void splitModuleByCategory(std::unique_ptr<Module> M, FunctionCategorizer FC,
+                           PostSplitCallbackType Callback);
+
+} // namespace sycl
+} // namespace llvm
+
+#endif // LLVM_FRONTEND_SYCL_SPLIT_MODULE_H

llvm/lib/Transforms/Utils/CMakeLists.txt

@@ -82,7 +82,9 @@ add_llvm_component_library(LLVMTransformUtils
   SimplifyLibCalls.cpp
   SizeOpts.cpp
   SplitModule.cpp
+  SplitModuleByCategory.cpp
   StripNonLineTableDebugInfo.cpp
+  SYCLUtils.cpp
   SymbolRewriter.cpp
   UnifyFunctionExitNodes.cpp
   UnifyLoopExits.cpp

llvm/lib/Transforms/Utils/SYCLUtils.cpp

@@ -0,0 +1,117 @@
+//===------------ SYCLUtils.cpp - SYCL utility functions ------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+// SYCL utility functions.
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Transforms/Utils/SYCLUtils.h"
+
+#include "llvm/ADT/StringExtras.h"
+#include "llvm/ADT/StringMap.h"
+#include "llvm/IR/Function.h"
+#include "llvm/IR/Module.h"
+#include "llvm/Support/raw_ostream.h"
+
+#include <optional>
+
+using namespace llvm;
+using namespace sycl;
+
+namespace {
+
+SmallString<0> computeFunctionCategoryForSplitting(IRSplitMode SM,
+                                                   const Function &F) {
+  static constexpr char ATTR_SYCL_MODULE_ID[] = "sycl-module-id";
+  SmallString<0> Key;
+  switch (SM) {
+  case IRSplitMode::IRSM_PER_KERNEL:
+    Key = F.getName().str();
+    break;
+  case IRSplitMode::IRSM_PER_TU:
+    Key = F.getFnAttribute(ATTR_SYCL_MODULE_ID).getValueAsString().str();
+    break;
+  default:
+    llvm_unreachable("other modes aren't expected");
+  }
+
+  return Key;
+}
+
+bool isKernel(const Function &F) {
+  return F.getCallingConv() == CallingConv::SPIR_KERNEL ||
+         F.getCallingConv() == CallingConv::AMDGPU_KERNEL ||
+         F.getCallingConv() == CallingConv::PTX_Kernel;
+}
+
+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);
+}
+
+} // anonymous namespace
+
+namespace llvm {
+namespace sycl {
+
+std::optional<IRSplitMode> convertStringToSplitMode(StringRef S) {
+  static const StringMap<IRSplitMode> Values = {
+      {"source", IRSplitMode::IRSM_PER_TU},
+      {"kernel", IRSplitMode::IRSM_PER_KERNEL},
+      {"none", IRSplitMode::IRSM_NONE}};
+
+  auto It = Values.find(S);
+  if (It == Values.end())
+    return std::nullopt;
+
+  return It->second;
+}
+
+FunctionCategorizer::FunctionCategorizer(IRSplitMode SM) : SM(SM) {
+  if (SM == IRSplitMode::IRSM_NONE)
+    llvm_unreachable("FunctionCategorizer isn't supported to none splitting.");
+}
+
+std::optional<int> FunctionCategorizer::operator()(const Function &F) {
+  if (!isEntryPoint(F))
+    return std::nullopt; // skip the function.
+
+  auto StringKey = computeFunctionCategoryForSplitting(SM, F);
+  if (auto it = StrKeyToID.find(StringRef(StringKey)); it != StrKeyToID.end())
+    return it->second;
+
+  int ID = static_cast<int>(StrKeyToID.size());
+  return StrKeyToID.try_emplace(std::move(StringKey), ID).first->second;
+}
+
+std::string makeSymbolTable(const Module &M) {
+  SmallString<0> Data;
+  raw_svector_ostream OS(Data);
+  for (const auto &F : M)
+    if (isEntryPoint(F))
+      OS << F.getName() << '\n';
+
+  return std::string(OS.str());
+}
+
+void writeStringTable(const StringTable &Table, raw_ostream &OS) {
+  assert(!Table.empty() && "table should contain at least column titles");
+  assert(!Table[0].empty() && "table should be non-empty");
+  OS << '[' << join(Table[0].begin(), Table[0].end(), "|") << "]\n";
+  for (size_t I = 1, E = Table.size(); I != E; ++I) {
+    assert(Table[I].size() == Table[0].size() && "row's size should be equal");
+    OS << join(Table[I].begin(), Table[I].end(), "|") << '\n';
+  }
+}
+
+} // namespace sycl
+} // namespace llvm