CMOptimizationsFence implementation

Implementation of CMOptimizationsFence class, which blocks optimizations between
modules.

Author: IDmitryy

clang/include/clang/FrontendPasses/OptFenceLowering.h

@@ -0,0 +1,34 @@
+/*========================== begin_copyright_notice ============================
+
+Copyright (C) 2022 Intel Corporation
+
+SPDX-License-Identifier: MIT
+
+============================= end_copyright_notice ===========================*/
+
+#include "llvm/IR/PassManager.h"
+
+namespace llvm {
+
+class ModulePass;
+class PassRegistry;
+
+//-----------------------------------------------------------------------------
+// New PM support
+//-----------------------------------------------------------------------------
+// Optimizations Fence Lowering pass for new PM.
+class OptFenceLowering final : public PassInfoMixin<OptFenceLowering> {
+public:
+  OptFenceLowering() = default;
+
+  PreservedAnalyses run(Module &M, ModuleAnalysisManager &AM);
+
+  static StringRef getArgString() { return "OptFenceLowering"; }
+};
+//-----------------------------------------------------------------------------
+// Legacy PM support
+//-----------------------------------------------------------------------------
+void initializeOptFenceLoweringLegacyPass(PassRegistry &);
+
+ModulePass *createOptFenceLoweringPass();
+} // namespace llvm

clang/lib/CMakeLists.txt

@@ -32,3 +32,4 @@ if(CLANG_ENABLE_STATIC_ANALYZER)
 endif()
 add_subdirectory(Format)
 add_subdirectory(FrontendWrapper)
+add_subdirectory(FrontendPasses)

clang/lib/CodeGen/BackendUtil.cpp

@@ -14,12 +14,14 @@ See LICENSE.TXT for details.
 ============================= end_copyright_notice ===========================*/
 
 #include "clang/CodeGen/BackendUtil.h"
+#include "LLVMSPIRVLib.h"
 #include "clang/Basic/CodeGenOptions.h"
 #include "clang/Basic/Diagnostic.h"
 #include "clang/Basic/LangOptions.h"
 #include "clang/Basic/TargetOptions.h"
 #include "clang/Frontend/FrontendDiagnostic.h"
 #include "clang/Frontend/Utils.h"
+#include "clang/FrontendPasses/OptFenceLowering.h"
 #include "clang/Lex/HeaderSearchOptions.h"
 #include "llvm/ADT/SmallSet.h"
 #include "llvm/ADT/StringExtras.h"
@@ -72,7 +74,6 @@ See LICENSE.TXT for details.
 #include "llvm/Transforms/Utils/CanonicalizeAliases.h"
 #include "llvm/Transforms/Utils/NameAnonGlobals.h"
 #include "llvm/Transforms/Utils/SymbolRewriter.h"
-#include "LLVMSPIRVLib.h"
 #include <memory>
 #include <sstream>
 using namespace clang;
@@ -575,6 +576,7 @@ void EmitAssemblyHelper::CreatePasses(legacy::PassManager &MPM,
   PMBuilder.RerollLoops = CodeGenOpts.RerollLoops;
 
   MPM.add(new TargetLibraryInfoWrapperPass(*TLII));
+  MPM.add(createOptFenceLoweringPass());
 
   if (TM)
     TM->adjustPassManager(PMBuilder);

clang/lib/CodeGen/CMakeLists.txt

@@ -117,6 +117,7 @@ add_clang_library(clangCodeGen
   clangFrontend
   clangLex
   clangSerialization
+  clangPasses
   )
 
 target_link_libraries(clangCodeGen PUBLIC LLVMSPIRVLib)

clang/lib/FrontendPasses/CMakeLists.txt

@@ -0,0 +1,34 @@
+#=========================== begin_copyright_notice ============================
+#
+# Copyright (C) 2022 Intel Corporation
+#
+# SPDX-License-Identifier: MIT
+#
+#============================ end_copyright_notice =============================
+
+
+# In a standard Clang+LLVM build, we need to generate intrinsics before
+# building codegen. In a standalone build, LLVM is already built and we don't
+# need this dependency. Furthermore, LLVM doesn't export it so we can't have
+# this dependency.
+set(frontendpasses_deps intrinsics_gen)
+if (CLANG_BUILT_STANDALONE)
+  set(frontendpasses_deps)
+endif()
+
+
+set(LLVM_LINK_COMPONENTS
+  ${LLVM_TARGETS_TO_BUILD}
+  Core
+  Support
+  Instrumentation
+  Passes
+  TransformUtils
+  )
+
+add_clang_library(clangPasses
+  OptFenceLowering.cpp
+
+  DEPENDS
+  ${frontendpasses_deps}
+  )