[ESIMD][NFC] Extract ESIMD handling from sycl-post-link to library. (#18684)

This change extracts handleESIMD from sycl-post-link to SYCLPostLink
component for reuse in NewOffloading compilation flow in clang and for
reuse in sycl-jit.

The body of `handleESIMD` function is refactored for better readability.

The documentation of lowerESIMDConstructs is fixed and the argument name
is changed to more straightforward.

Author: maksimsab

llvm/include/llvm/SYCLPostLink/ESIMDPostSplitProcessing.h

@@ -9,16 +9,57 @@
 // required optimimizations.
 //===----------------------------------------------------------------------===//
 
+#ifndef LLVM_SYCL_POST_LINK_ESIMD_POST_SPLIT_PROCESSING_H
+#define LLVM_SYCL_POST_LINK_ESIMD_POST_SPLIT_PROCESSING_H
+
 #include "llvm/SYCLPostLink/ModuleSplitter.h"
 
+#include "llvm/ADT/SmallVector.h"
+#include "llvm/Support/Error.h"
+
 namespace llvm {
 namespace sycl {
 
+struct ESIMDProcessingOptions {
+  llvm::module_split::IRSplitMode SplitMode =
+      llvm::module_split::IRSplitMode::SPLIT_NONE;
+  bool EmitOnlyKernelsAsEntryPoints = false;
+  bool AllowDeviceImageDependencies = false;
+  bool LowerESIMD = false;
+  bool SplitESIMD = false;
+  unsigned OptLevel = 0;
+  bool ForceDisableESIMDOpt = false;
+};
+
 /// Lowers ESIMD constructs after separation from regular SYCL code.
-/// \SplitESIMD identifies that ESIMD splitting is requested in the compilation.
-/// Returns true if the given \MD has been modified.
-bool lowerESIMDConstructs(llvm::module_split::ModuleDesc &MD, bool OptLevelO0,
-                          bool SplitESIMD);
+/// \p Options.SplitESIMD identifies that ESIMD splitting is requested in the
+/// compilation. Returns true if the given \p MD has been modified.
+bool lowerESIMDConstructs(llvm::module_split::ModuleDesc &MD,
+                          const ESIMDProcessingOptions &Options);
+
+/// Performs ESIMD processing that happens in the following steps:
+///  1) Separate ESIMD Module from SYCL code.
+///     \p Options.EmitOnlyKernelsAsEntryPoints and
+///     \p Options.AllowDeviceImageDependencies are being used in the splitting.
+///  2) If \p Options.LowerESIMD is true then ESIMD lowering pipeline is applied
+///  to the ESIMD Module.
+///     If \p Options.OptLevel is not O0 then ESIMD Module is being optimized
+///     after the lowering.
+///  3.1) If \p Options.SplitESIMD is true then both ESIMD and non-ESIMD modules
+///  are returned.
+///  3.2) Otherwise, two Modules are being linked into one Module which is
+///     returned. After the linking graphs become disjoint because functions
+///     shared between graphs are cloned and renamed.
+///
+/// \p Modified value indicates whether the Module has been modified.
+/// \p SplitOccurred value indicates whether split has occurred before or during
+/// function's invocation.
+Expected<SmallVector<module_split::ModuleDesc, 2>>
+handleESIMD(llvm::module_split::ModuleDesc MDesc,
+            const ESIMDProcessingOptions &Options, bool &Modified,
+            bool &SplitOccurred);
 
 } // namespace sycl
 } // namespace llvm
+
+#endif // LLVM_SYCL_POST_LINK_ESIMD_POST_SPLIT_PROCESSING_H

llvm/lib/SYCLPostLink/CMakeLists.txt

@@ -24,6 +24,7 @@ add_llvm_component_library(LLVMSYCLPostLink
   Demangle
   InstCombine
   IRPrinter
+  Linker
   Passes
   ScalarOpts
   Support

llvm/lib/SYCLPostLink/ESIMDPostSplitProcessing.cpp

@@ -11,9 +11,11 @@
 #include "llvm/SYCLPostLink/ESIMDPostSplitProcessing.h"
 
 #include "llvm/GenXIntrinsics/GenXSPIRVWriterAdaptor.h"
+#include "llvm/Linker/Linker.h"
 #include "llvm/Passes/PassBuilder.h"
 #include "llvm/SYCLLowerIR/ESIMD/LowerESIMD.h"
 #include "llvm/SYCLPostLink/ModuleSplitter.h"
+#include "llvm/Support/FormatVariadic.h"
 #include "llvm/Transforms/IPO/AlwaysInliner.h"
 #include "llvm/Transforms/IPO/StripDeadPrototypes.h"
 #include "llvm/Transforms/InstCombine/InstCombine.h"
@@ -30,12 +32,12 @@ using namespace llvm::module_split;
 
 namespace {
 
-ModulePassManager buildESIMDLoweringPipeline(bool ForceDisableESIMDOpt,
-                                             bool SplitESIMD) {
+ModulePassManager
+buildESIMDLoweringPipeline(const sycl::ESIMDProcessingOptions &Options) {
   ModulePassManager MPM;
-  MPM.addPass(SYCLLowerESIMDPass(!SplitESIMD));
+  MPM.addPass(SYCLLowerESIMDPass(!Options.SplitESIMD));
 
-  if (!ForceDisableESIMDOpt) {
+  if (!Options.ForceDisableESIMDOpt) {
     FunctionPassManager FPM;
     FPM.addPass(SROAPass(SROAOptions::ModifyCFG));
     MPM.addPass(createModuleToFunctionPassAdaptor(std::move(FPM)));
@@ -44,7 +46,7 @@ ModulePassManager buildESIMDLoweringPipeline(bool ForceDisableESIMDOpt,
   FunctionPassManager MainFPM;
   MainFPM.addPass(ESIMDLowerLoadStorePass{});
 
-  if (!ForceDisableESIMDOpt) {
+  if (!Options.ForceDisableESIMDOpt) {
     MainFPM.addPass(SROAPass(SROAOptions::ModifyCFG));
     MainFPM.addPass(EarlyCSEPass(true));
     MainFPM.addPass(InstCombinePass{});
@@ -61,12 +63,29 @@ ModulePassManager buildESIMDLoweringPipeline(bool ForceDisableESIMDOpt,
   return MPM;
 }
 
+Expected<ModuleDesc> linkModules(ModuleDesc MD1, ModuleDesc MD2) {
+  std::vector<std::string> Names;
+  MD1.saveEntryPointNames(Names);
+  MD2.saveEntryPointNames(Names);
+  bool LinkError =
+      llvm::Linker::linkModules(MD1.getModule(), MD2.releaseModulePtr());
+
+  if (LinkError)
+    return createStringError(
+        formatv("link failed. Module names: {0}, {1}", MD1.Name, MD2.Name));
+
+  ModuleDesc Res(MD1.releaseModulePtr(), std::move(Names));
+  Res.assignMergedProperties(MD1, MD2);
+  Res.Name = (Twine("linked[") + MD1.Name + "," + MD2.Name + "]").str();
+  return std::move(Res);
+}
+
 } // anonymous namespace
 
 // When ESIMD code was separated from the regular SYCL code,
 // we can safely process ESIMD part.
-bool sycl::lowerESIMDConstructs(ModuleDesc &MD, bool ForceDisableESIMDOpt,
-                                bool SplitESIMD) {
+bool sycl::lowerESIMDConstructs(ModuleDesc &MD,
+                                const sycl::ESIMDProcessingOptions &Options) {
   // TODO: support options like -debug-pass, -print-[before|after], and others
   LoopAnalysisManager LAM;
   CGSCCAnalysisManager CGAM;
@@ -82,12 +101,64 @@ bool sycl::lowerESIMDConstructs(ModuleDesc &MD, bool ForceDisableESIMDOpt,
 
   std::vector<std::string> Names;
   MD.saveEntryPointNames(Names);
-  ModulePassManager MPM =
-      buildESIMDLoweringPipeline(ForceDisableESIMDOpt, SplitESIMD);
+  ModulePassManager MPM = buildESIMDLoweringPipeline(Options);
   PreservedAnalyses Res = MPM.run(MD.getModule(), MAM);
 
   // GenXSPIRVWriterAdaptor pass replaced some functions with "rewritten"
   // versions so the entry point table must be rebuilt.
   MD.rebuildEntryPoints(Names);
   return !Res.areAllPreserved();
 }
+
+Expected<SmallVector<ModuleDesc, 2>>
+llvm::sycl::handleESIMD(ModuleDesc MDesc,
+                        const sycl::ESIMDProcessingOptions &Options,
+                        bool &Modified, bool &SplitOccurred) {
+  SmallVector<ModuleDesc, 2> Result =
+      splitByESIMD(std::move(MDesc), Options.EmitOnlyKernelsAsEntryPoints,
+                   Options.AllowDeviceImageDependencies);
+
+  assert(Result.size() <= 2 &&
+         "Split modules aren't expected to be more than 2.");
+
+  SplitOccurred |= Result.size() > 1;
+
+  for (ModuleDesc &MD : Result) {
+#ifdef LLVM_ENABLE_DUMP
+    dumpEntryPoints(MD.entries(), MD.Name.c_str(), 4);
+#endif // LLVM_ENABLE_DUMP
+    if (Options.LowerESIMD && MD.isESIMD())
+      Modified |= lowerESIMDConstructs(MD, Options);
+  }
+
+  if (Options.SplitESIMD || Result.size() == 1)
+    return std::move(Result);
+
+  // SYCL/ESIMD splitting is not requested, link back into single module.
+  int ESIMDInd = Result[0].isESIMD() ? 0 : 1;
+  int SYCLInd = 1 - ESIMDInd;
+  assert(Result[SYCLInd].isSYCL() &&
+         "Result[SYCLInd].isSYCL() expected to be true.");
+
+  // Make sure that no link conflicts occur.
+  Result[ESIMDInd].renameDuplicatesOf(Result[SYCLInd].getModule(), ".esimd");
+  auto LinkedOrErr = linkModules(std::move(Result[0]), std::move(Result[1]));
+  if (!LinkedOrErr)
+    return LinkedOrErr.takeError();
+
+  ModuleDesc &Linked = *LinkedOrErr;
+  Linked.restoreLinkageOfDirectInvokeSimdTargets();
+  std::vector<std::string> Names;
+  Linked.saveEntryPointNames(Names);
+  // Cleanup may remove some entry points, need to save/rebuild.
+  Linked.cleanup(Options.AllowDeviceImageDependencies);
+  Linked.rebuildEntryPoints(Names);
+  Result.clear();
+  Result.emplace_back(std::move(Linked));
+#ifdef LLVM_ENABLE_DUMP
+  dumpEntryPoints(Result.back().entries(), Result.back().Name.c_str(), 4);
+#endif // LLVM_ENABLE_DUMP
+  Modified = true;
+
+  return std::move(Result);
+}

llvm/tools/sycl-post-link/CMakeLists.txt

@@ -9,7 +9,6 @@ set(LLVM_LINK_COMPONENTS
   TransformUtils
   SYCLLowerIR
   SYCLPostLink
-  Linker
   Passes
   Analysis
   )

llvm/tools/sycl-post-link/sycl-post-link.cpp

@@ -59,8 +59,6 @@
 using namespace llvm;
 using namespace llvm::sycl;
 
-using string_vector = std::vector<std::string>;
-
 namespace {
 
 #ifdef NDEBUG
@@ -263,6 +261,19 @@ struct IrPropSymFilenameTriple {
   std::string Sym;
 };
 
+unsigned getOptLevel() {
+  if (OptLevelO3)
+    return 3;
+  if (OptLevelO2 || OptLevelOs || OptLevelOz)
+    return 2;
+  if (OptLevelO1)
+    return 1;
+  if (OptLevelO0)
+    return 0;
+
+  return 2; // default value
+}
+
 static void writeToFile(const StringRef Filename, const StringRef Content) {
   std::error_code EC;
   raw_fd_ostream OS{Filename, EC, sys::fs::OpenFlags::OF_None};
@@ -418,23 +429,6 @@ void saveDeviceLibModule(
   saveModule(OutTables, DeviceLibMD, I, OutputPrefix, "");
 }
 
-module_split::ModuleDesc link(module_split::ModuleDesc &&MD1,
-                              module_split::ModuleDesc &&MD2) {
-  std::vector<std::string> Names;
-  MD1.saveEntryPointNames(Names);
-  MD2.saveEntryPointNames(Names);
-  bool LinkError =
-      llvm::Linker::linkModules(MD1.getModule(), MD2.releaseModulePtr());
-
-  if (LinkError) {
-    error(" error when linking SYCL and ESIMD modules");
-  }
-  module_split::ModuleDesc Res(MD1.releaseModulePtr(), std::move(Names));
-  Res.assignMergedProperties(MD1, MD2);
-  Res.Name = "linked[" + MD1.Name + "," + MD2.Name + "]";
-  return Res;
-}
-
 bool processSpecConstants(module_split::ModuleDesc &MD) {
   MD.Props.SpecConstsMet = false;
 
@@ -500,65 +494,6 @@ void addTableRow(util::SimpleTable &Table,
   Table.addRow(Row);
 }
 
-SmallVector<module_split::ModuleDesc, 2>
-handleESIMD(module_split::ModuleDesc &&MDesc, bool &Modified,
-            bool &SplitOccurred) {
-  // Do SYCL/ESIMD splitting. It happens always, as ESIMD and SYCL must
-  // undergo different set of LLVMIR passes. After this they are linked back
-  // together to form single module with disjoint SYCL and ESIMD call graphs
-  // unless -split-esimd option is specified. The graphs become disjoint
-  // when linked back because functions shared between graphs are cloned and
-  // renamed.
-  SmallVector<module_split::ModuleDesc, 2> Result =
-      module_split::splitByESIMD(std::move(MDesc), EmitOnlyKernelsAsEntryPoints,
-                                 AllowDeviceImageDependencies);
-
-  if (Result.size() > 1 && SplitOccurred &&
-      (SplitMode == module_split::SPLIT_PER_KERNEL) && !SplitEsimd) {
-    // Controversial state reached - SYCL and ESIMD entry points resulting
-    // from SYCL/ESIMD split (which is done always) are linked back, since
-    // -split-esimd is not specified, but per-kernel split is requested.
-    warning("SYCL and ESIMD entry points detected and split mode is "
-            "per-kernel, so " +
-            SplitEsimd.ValueStr + " must also be specified");
-  }
-  SplitOccurred |= Result.size() > 1;
-
-  for (auto &MD : Result) {
-    DUMP_ENTRY_POINTS(MD.entries(), MD.Name.c_str(), 3);
-    if (LowerEsimd && MD.isESIMD())
-      Modified |=
-          sycl::lowerESIMDConstructs(MD, ForceDisableESIMDOpt, SplitEsimd);
-  }
-
-  if (!SplitEsimd && Result.size() > 1) {
-    // SYCL/ESIMD splitting is not requested, link back into single module.
-    assert(Result.size() == 2 &&
-           "Unexpected number of modules as results of ESIMD split");
-    int ESIMDInd = Result[0].isESIMD() ? 0 : 1;
-    int SYCLInd = 1 - ESIMDInd;
-    assert(Result[SYCLInd].isSYCL() &&
-           "no non-ESIMD module as a result ESIMD split?");
-
-    // ... but before that, make sure no link conflicts will occur.
-    Result[ESIMDInd].renameDuplicatesOf(Result[SYCLInd].getModule(), ".esimd");
-    module_split::ModuleDesc Linked =
-        link(std::move(Result[0]), std::move(Result[1]));
-    Linked.restoreLinkageOfDirectInvokeSimdTargets();
-    string_vector Names;
-    Linked.saveEntryPointNames(Names);
-    // cleanup may remove some entry points, need to save/rebuild
-    Linked.cleanup(AllowDeviceImageDependencies);
-    Linked.rebuildEntryPoints(Names);
-    Result.clear();
-    Result.emplace_back(std::move(Linked));
-    DUMP_ENTRY_POINTS(Result.back().entries(), Result.back().Name.c_str(), 3);
-    Modified = true;
-  }
-
-  return Result;
-}
-
 // Checks if the given target and module are compatible.
 // A target and module are compatible if all the optional kernel features
 // the module uses are supported by that target (i.e. that module can be
@@ -676,10 +611,18 @@ processInputModule(std::unique_ptr<Module> M, const StringRef OutputPrefix) {
 
     MDesc.fixupLinkageOfDirectInvokeSimdTargets();
 
-    SmallVector<module_split::ModuleDesc, 2> MMs =
-        handleESIMD(std::move(MDesc), Modified, SplitOccurred);
+    ESIMDProcessingOptions Options = {SplitMode,
+                                      EmitOnlyKernelsAsEntryPoints,
+                                      AllowDeviceImageDependencies,
+                                      LowerEsimd,
+                                      SplitEsimd,
+                                      getOptLevel(),
+                                      ForceDisableESIMDOpt};
+    auto ModulesOrErr =
+        handleESIMD(std::move(MDesc), Options, Modified, SplitOccurred);
+    CHECK_AND_EXIT(ModulesOrErr.takeError());
+    SmallVector<module_split::ModuleDesc, 2> &MMs = *ModulesOrErr;
     assert(MMs.size() && "at least one module is expected after ESIMD split");
-
     SmallVector<module_split::ModuleDesc, 2> MMsWithDefaultSpecConsts;
     for (size_t I = 0; I != MMs.size(); ++I) {
       if (GenerateDeviceImageWithDefaultSpecConsts) {