[SYCL][NFC] Move SYCL Module Splitting to library. Part 1 (#13054)

This patch is a part 1 of moving sycl-post-link functionality to library for New Offloading initiative. This patch replaces `std::vector<char>` with `MemoryBuffer` as a container for accessing device image in the `SYCLImage` class. `MemoryBuffer` uses `mmap` that allows not to hold the whole device image in the RAM.
intel · Mar 27, 2024 · bb48303 · bb48303
1 parent 25b75ea
commit bb48303
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Showing 3 changed files with 28 additions and 23 deletions.
diff --git a/clang/tools/clang-linker-wrapper/ClangLinkerWrapper.cpp b/clang/tools/clang-linker-wrapper/ClangLinkerWrapper.cpp
@@ -714,16 +714,6 @@ static Expected<StringRef> runLLVMToSPIRVTranslation(StringRef InputTable,
   return *Output;
 }
 
-Expected<std::vector<char>> readBinaryFile(StringRef File) {
-  auto MBOrErr = MemoryBuffer::getFile(File, /*IsText*/ false,
-                                       /*RequiresNullTerminator */ false);
-  if (!MBOrErr)
-    return createFileError(File, MBOrErr.getError());
-
-  auto &MB = *MBOrErr;
-  return std::vector<char>(MB->getBufferStart(), MB->getBufferEnd());
-}
-
 Expected<std::string> readTextFile(StringRef File) {
   auto MBOrErr = MemoryBuffer::getFile(File, /*IsText*/ true,
                                        /*RequiresNullTerminator */ true);
@@ -768,9 +758,10 @@ readSYCLImagesFromTable(StringRef TableFile, const ArgList &Args) {
 
   SmallVector<offloading::SYCLImage> Images;
   for (const util::SimpleTable::Row &row : Table->rows()) {
-    auto ImageOrErr = readBinaryFile(row.getCell("Code"));
+    auto ImagePath = row.getCell("Code");
+    auto ImageOrErr = MemoryBuffer::getFile(ImagePath);
     if (!ImageOrErr)
-      return ImageOrErr.takeError();
+      return createFileError(ImagePath, ImageOrErr.getError());
 
     auto PropertiesOrErr =
         readPropertyRegistryFromFile(row.getCell("Properties"));
@@ -788,7 +779,7 @@ readSYCLImagesFromTable(StringRef TableFile, const ArgList &Args) {
     Images.push_back(std::move(Image));
   }
 
-  return Images;
+  return std::move(Images);
 }
 
 /// Reads device images from the given \p InputFile and wraps them

diff --git a/llvm/include/llvm/Frontend/Offloading/SYCLOffloadWrapper.h b/llvm/include/llvm/Frontend/Offloading/SYCLOffloadWrapper.h
@@ -12,6 +12,7 @@
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/IR/Module.h"
+#include "llvm/Support/MemoryBuffer.h"
 #include "llvm/Support/PropertySetIO.h"
 
 #include <string>
@@ -30,7 +31,20 @@ enum class SYCLBinaryImageFormat {
 };
 
 struct SYCLImage {
-  std::vector<char> Image;
+  SYCLImage() = default;
+  SYCLImage(const SYCLImage &) = delete;
+  SYCLImage &operator=(const SYCLImage &) = delete;
+  SYCLImage(SYCLImage &&) = default;
+  SYCLImage &operator=(SYCLImage &&) = default;
+
+  SYCLImage(std::unique_ptr<llvm::MemoryBuffer> Image,
+            const llvm::util::PropertySetRegistry &Registry,
+            llvm::StringRef Entries, llvm::StringRef Target = "")
+      : Image(std::move(Image)), PropertyRegistry(std::move(Registry)),
+        Entries(Entries.begin(), Entries.size()),
+        Target(Target.begin(), Target.size()) {}
+
+  std::unique_ptr<llvm::MemoryBuffer> Image;
   llvm::util::PropertySetRegistry PropertyRegistry;
 
   std::string Entries;
@@ -57,7 +71,7 @@ struct SYCLWrappingOptions {
 /// as global symbols and registers the images with the SYCL Runtime.
 /// \param Options Settings that allows to turn on optional data and settings.
 llvm::Error
-wrapSYCLBinaries(llvm::Module &M, llvm::SmallVector<SYCLImage> &Images,
+wrapSYCLBinaries(llvm::Module &M, const llvm::SmallVector<SYCLImage> &Images,
                  SYCLWrappingOptions Options = SYCLWrappingOptions());
 
 } // namespace offloading

diff --git a/llvm/lib/Frontend/Offloading/SYCLOffloadWrapper.cpp b/llvm/lib/Frontend/Offloading/SYCLOffloadWrapper.cpp
@@ -556,8 +556,10 @@ struct Wrapper {
     if (Image.Target == "native_cpu")
       Binary = addDeclarationsForNativeCPU(Image.Entries);
     else {
+      auto &MB = *Image.Image;
       Binary = addDeviceImageToModule(
-          Image.Image, Twine(OffloadKindTag) + ImageID + ".data", Image.Target);
+          ArrayRef<char>(MB.getBufferStart(), MB.getBufferEnd()),
+          Twine(OffloadKindTag) + ImageID + ".data", Image.Target);
     }
 
     // TODO: Manifests are going to be removed.
@@ -576,8 +578,8 @@ struct Wrapper {
         PropSets.first, PropSets.second);
 
     if (Options.EmitRegistrationFunctions)
-      emitRegistrationFunctions(Binary.first, Image.Image.size(), ImageID,
-                                OffloadKindTag);
+      emitRegistrationFunctions(Binary.first, Image.Image->getBufferSize(),
+                                ImageID, OffloadKindTag);
 
     return WrappedImage;
   }
@@ -669,14 +671,12 @@ struct Wrapper {
   /// \endcode
   ///
   /// \returns Global variable that represents FatbinDesc.
-  GlobalVariable *createFatbinDesc(SmallVector<SYCLImage> &Images) {
+  GlobalVariable *createFatbinDesc(const SmallVector<SYCLImage> &Images) {
     const char *OffloadKindTag = ".sycl_offloading.";
     SmallVector<Constant *> WrappedImages;
     WrappedImages.reserve(Images.size());
-    for (size_t i = 0; i != Images.size(); ++i) {
+    for (size_t i = 0; i != Images.size(); ++i)
       WrappedImages.push_back(wrapImage(Images[i], Twine(i), OffloadKindTag));
-      Images[i].Image.clear(); // This is just for economy of RAM.
-    }
 
     return combineWrappedImages(WrappedImages, OffloadKindTag);
   }
@@ -729,7 +729,7 @@ struct Wrapper {
 } // anonymous namespace
 
 Error llvm::offloading::wrapSYCLBinaries(llvm::Module &M,
-                                         SmallVector<SYCLImage> &Images,
+                                         const SmallVector<SYCLImage> &Images,
                                          SYCLWrappingOptions Options) {
   Wrapper W(M, Options);
   GlobalVariable *Desc = W.createFatbinDesc(Images);