[SYCL] Make SYCL RT compatible with the new offload entry type (#17109)

llvm/llvm-project#124018 change the type of
offload struct. This PR makes SYCL RT compatible with the new format,
while keeping backwards compatibility with the older version (till next
ABI-break window).

---------

Co-authored-by: Sergey Semenov <[email protected]>

Author: uditagarwal97

clang/test/Driver/sycl-linker-wrapper-image.cpp

@@ -37,7 +37,7 @@ int main() {
 
 // CHECK-DAG: %_pi_device_binary_property_struct = type { ptr, ptr, i32, i64 }
 // CHECK-DAG: %_pi_device_binary_property_set_struct = type { ptr, ptr, ptr }
-// CHECK-DAG: %struct.__tgt_offload_entry = type { ptr, ptr, i64, i32, i32 }
+// CHECK-DAG: %struct.__tgt_offload_entry = type { i64, i16, i16, i32, ptr, ptr, i64, i64, ptr }
 // CHECK-DAG: %__sycl.tgt_device_image = type { i16, i8, i8, ptr, ptr, ptr, ptr, ptr, ptr, ptr, ptr, ptr, ptr, ptr }
 // CHECK-DAG: %__sycl.tgt_bin_desc = type { i16, i16, ptr, ptr, ptr }
 
@@ -55,7 +55,7 @@ int main() {
 // CHECK-DAG: @__sycl_offload_prop_sets_arr.5 = internal constant [3 x %_pi_device_binary_property_set_struct] [%_pi_device_binary_property_set_struct { ptr @SYCL_PropSetName, ptr @__sycl_offload_prop_sets_arr, ptr getelementptr ([1 x %_pi_device_binary_property_struct], ptr @__sycl_offload_prop_sets_arr, i64 0, i64 1) }, %_pi_device_binary_property_set_struct { ptr @SYCL_PropSetName.3, ptr @__sycl_offload_prop_sets_arr.2, ptr getelementptr ([1 x %_pi_device_binary_property_struct], ptr @__sycl_offload_prop_sets_arr.2, i64 0, i64 1) }, %_pi_device_binary_property_set_struct { ptr @SYCL_PropSetName.4, ptr null, ptr null }]
 // CHECK-DAG: @.sycl_offloading.0.data = internal unnamed_addr constant [912 x i8]
 // CHECK-DAG: @__sycl_offload_entry_name = internal unnamed_addr constant [25 x i8] c"_ZTSZ4mainE11fake_kernel\00"
-// CHECK-DAG: @__sycl_offload_entries_arr = internal constant [1 x %struct.__tgt_offload_entry] [%struct.__tgt_offload_entry { ptr null, ptr @__sycl_offload_entry_name, i64 0, i32 0, i32 0 }]
+// CHECK-DAG: @__sycl_offload_entries_arr = internal constant [1 x %struct.__tgt_offload_entry] [%struct.__tgt_offload_entry { i64 0, i16 1, i16 4, i32 0, ptr null, ptr @__sycl_offload_entry_name, i64 0, i64 0, ptr null }]
 // CHECK-DAG: @.sycl_offloading.0.info = internal local_unnamed_addr constant [2 x i64] [i64 ptrtoint (ptr @.sycl_offloading.0.data to i64), i64 912], section ".tgtimg", align 16
 // CHECK-DAG: @llvm.used = appending global [1 x ptr] [ptr @.sycl_offloading.0.info], section "llvm.metadata"
 // CHECK-DAG: @.sycl_offloading.device_images = internal unnamed_addr constant [1 x %__sycl.tgt_device_image] [%__sycl.tgt_device_image { i16 2, i8 4, i8 0, ptr @.sycl_offloading.target.0, ptr @.sycl_offloading.opts.compile.0, ptr @.sycl_offloading.opts.link.0, ptr null, ptr null, ptr @.sycl_offloading.0.data, ptr getelementptr ([912 x i8], ptr @.sycl_offloading.0.data, i64 0, i64 912), ptr @__sycl_offload_entries_arr, ptr getelementptr ([1 x %struct.__tgt_offload_entry], ptr @__sycl_offload_entries_arr, i64 0, i64 1), ptr @__sycl_offload_prop_sets_arr.5, ptr getelementptr ([3 x %_pi_device_binary_property_set_struct], ptr @__sycl_offload_prop_sets_arr.5, i64 0, i64 3) }]

llvm/lib/Frontend/Offloading/SYCLOffloadWrapper.cpp

@@ -62,18 +62,6 @@ int8_t binaryImageFormatToInt8(SYCLBinaryImageFormat Format) {
   }
 }
 
-StructType* getLegacyOffloadEntryTy(Module &M) {
-  LLVMContext &C = M.getContext();
-  StructType *EntryTy =
-      StructType::getTypeByName(C, "struct.__tgt_offload_entry");
-  if (!EntryTy)
-    EntryTy = StructType::create(
-        "struct.__tgt_offload_entry", PointerType::getUnqual(C),
-        PointerType::getUnqual(C), M.getDataLayout().getIntPtrType(C),
-        Type::getInt32Ty(C), Type::getInt32Ty(C));
-  return EntryTy;
-}
-
 /// Wrapper helper class that creates all LLVM IRs wrapping given images.
 /// Note: All created structures, "_pi_device_*", "__sycl_*" and "__tgt*" names
 /// in this implementation are aligned with "sycl/include/sycl/detail/pi.h".
@@ -95,7 +83,7 @@ struct Wrapper {
 
     SyclPropTy = getSyclPropTy();
     SyclPropSetTy = getSyclPropSetTy();
-    EntryTy = getLegacyOffloadEntryTy(M);
+    EntryTy = offloading::getEntryTy(M);
     SyclDeviceImageTy = getSyclDeviceImageTy();
     SyclBinDescTy = getSyclBinDescTy();
   }
@@ -399,16 +387,26 @@ struct Wrapper {
       return std::pair<Constant *, Constant *>(NullPtr, NullPtr);
     }
 
-    auto *Zero = ConstantInt::get(getSizeTTy(), 0);
+    auto *I64Zero = ConstantInt::get(Type::getInt64Ty(C), 0);
     auto *I32Zero = ConstantInt::get(Type::getInt32Ty(C), 0);
     auto *NullPtr = Constant::getNullValue(PointerType::getUnqual(C));
 
     SmallVector<Constant *> EntriesInits;
     std::unique_ptr<MemoryBuffer> MB = MemoryBuffer::getMemBuffer(Entries);
-    for (line_iterator LI(*MB); !LI.is_at_eof(); ++LI)
-      EntriesInits.push_back(ConstantStruct::get(
-          EntryTy, NullPtr, addStringToModule(*LI, "__sycl_offload_entry_name"),
-          Zero, I32Zero, I32Zero));
+    for (line_iterator LI(*MB); !LI.is_at_eof(); ++LI) {
+      Constant *EntryData[] = {
+          ConstantExpr::getNullValue(Type::getInt64Ty(C)),
+          ConstantInt::get(Type::getInt16Ty(C), 1),
+          ConstantInt::get(Type::getInt16Ty(C), object::OffloadKind::OFK_SYCL),
+          I32Zero,
+          NullPtr,
+          addStringToModule(*LI, "__sycl_offload_entry_name"),
+          I64Zero,
+          I64Zero,
+          NullPtr};
+
+      EntriesInits.push_back(ConstantStruct::get(EntryTy, EntryData));
+    }
 
     auto *Arr = ConstantArray::get(ArrayType::get(EntryTy, EntriesInits.size()),
                                    EntriesInits);

sycl/source/detail/compiler.hpp

@@ -78,13 +78,70 @@
 
 #define __SYCL_PROGRAM_METADATA_TAG_NEED_FINALIZATION "Requires finalization"
 
+// New entry type after
+// https://github.com/llvm/llvm-project/pull/124018
+// This is a replica of the EntryTy data structure in
+// llvm/include/llvm/Frontend/Offloading/Utility.h.
+struct _sycl_offload_entry_struct_new {
+  /// Reserved bytes used to detect an older version of the struct, always zero.
+  uint64_t Reserved;
+  /// The current version of the struct for runtime forward compatibility.
+  uint16_t Version;
+  /// The expected consumer of this entry, e.g. CUDA or OpenMP.
+  uint16_t Kind;
+  /// Flags associated with the global.
+  uint32_t Flags;
+  /// The address of the global to be registered by the runtime.
+  void *Address;
+  /// The name of the symbol in the device image.
+  char *SymbolName;
+  /// The number of bytes the symbol takes.
+  uint64_t Size;
+  /// Extra generic data used to register this entry.
+  uint64_t Data;
+  /// An extra pointer, usually null.
+  void *AuxAddr;
+};
+using sycl_offload_entry_new = _sycl_offload_entry_struct_new *;
+
 // Entry type, matches OpenMP for compatibility
 struct _sycl_offload_entry_struct {
   void *addr;
   char *name;
   size_t size;
   int32_t flags;
   int32_t reserved;
+
+  inline bool IsNewOffloadEntryType() {
+    // Assume this is the new version of the struct.
+    auto newStruct = reinterpret_cast<sycl_offload_entry_new>(this);
+
+    // Check if first 64 bits is equal to 0, next 16 bits is equal to 1, next 16
+    // bits is equal to 4 (OK_SYCL), and check if Flags are zero. If all these
+    // conditions are met, then this is a newer version of the struct.
+    // We can not just rely on checking the first 64 bits, because even for the
+    // older version of the struct, the first 64 bits (void* addr) are zero.
+    return newStruct->Reserved == 0 && newStruct->Version == 1 &&
+           newStruct->Kind == 4 && newStruct->Flags == 0;
+  }
+
+  // Name is the only field that's used in SYCL.
+  inline char *GetName() {
+    if (IsNewOffloadEntryType())
+      return reinterpret_cast<sycl_offload_entry_new>(this)->SymbolName;
+
+    return name;
+  }
+
+  // Increment the pointer to the next entry. A mix of old and new offload entry
+  // types is not supported.
+  inline _sycl_offload_entry_struct *Increment() {
+    if (IsNewOffloadEntryType())
+      return reinterpret_cast<_sycl_offload_entry_struct *>(
+          reinterpret_cast<sycl_offload_entry_new>(this) + 1);
+
+    return this + 1;
+  }
 };
 using sycl_offload_entry = _sycl_offload_entry_struct *;
 

sycl/source/detail/device_binary_image.cpp

@@ -120,9 +120,10 @@ void RTDeviceBinaryImage::print() const {
   std::cerr << "    Link options    : "
             << (Bin->LinkOptions ? Bin->LinkOptions : "NULL") << "\n";
   std::cerr << "    Entries  : ";
+
   for (sycl_offload_entry EntriesIt = Bin->EntriesBegin;
-       EntriesIt != Bin->EntriesEnd; ++EntriesIt)
-    std::cerr << EntriesIt->name << " ";
+       EntriesIt != Bin->EntriesEnd; EntriesIt = EntriesIt->Increment())
+    std::cerr << EntriesIt->GetName() << " ";
   std::cerr << "\n";
   std::cerr << "    Properties [" << Bin->PropertySetsBegin << "-"
             << Bin->PropertySetsEnd << "]:\n";

sycl/source/detail/persistent_device_code_cache.cpp

@@ -103,8 +103,8 @@ getSortedImages(const std::vector<const RTDeviceBinaryImage *> &Imgs) {
             [](const RTDeviceBinaryImage *A, const RTDeviceBinaryImage *B) {
               // All entry names are unique among these images, so comparing the
               // first ones is enough.
-              return std::strcmp(A->getRawData().EntriesBegin->name,
-                                 B->getRawData().EntriesBegin->name) < 0;
+              return std::strcmp(A->getRawData().EntriesBegin->GetName(),
+                                 B->getRawData().EntriesBegin->GetName()) < 0;
             });
   return SortedImgs;
 }

sycl/source/detail/program_manager/program_manager.cpp

@@ -1867,33 +1867,34 @@ void ProgramManager::addImages(sycl_device_binaries DeviceBinary) {
     m_BinImg2KernelIDs[Img.get()].reset(new std::vector<kernel_id>);
 
     for (sycl_offload_entry EntriesIt = EntriesB; EntriesIt != EntriesE;
-         ++EntriesIt) {
+         EntriesIt = EntriesIt->Increment()) {
+
+      auto name = EntriesIt->GetName();
 
       // Skip creating unique kernel ID if it is a service kernel.
       // SYCL service kernels are identified by having
       // __sycl_service_kernel__ in the mangled name, primarily as part of
       // the namespace of the name type.
-      if (std::strstr(EntriesIt->name, "__sycl_service_kernel__")) {
-        m_ServiceKernels.insert(std::make_pair(EntriesIt->name, Img.get()));
+      if (std::strstr(name, "__sycl_service_kernel__")) {
+        m_ServiceKernels.insert(std::make_pair(name, Img.get()));
         continue;
       }
 
       // Skip creating unique kernel ID if it is an exported device
       // function. Exported device functions appear in the offload entries
       // among kernels, but are identifiable by being listed in properties.
-      if (m_ExportedSymbolImages.find(EntriesIt->name) !=
-          m_ExportedSymbolImages.end())
+      if (m_ExportedSymbolImages.find(name) != m_ExportedSymbolImages.end())
         continue;
 
       // ... and create a unique kernel ID for the entry
-      auto It = m_KernelName2KernelIDs.find(EntriesIt->name);
+      auto It = m_KernelName2KernelIDs.find(name);
       if (It == m_KernelName2KernelIDs.end()) {
         std::shared_ptr<detail::kernel_id_impl> KernelIDImpl =
-            std::make_shared<detail::kernel_id_impl>(EntriesIt->name);
+            std::make_shared<detail::kernel_id_impl>(name);
         sycl::kernel_id KernelID =
             detail::createSyclObjFromImpl<sycl::kernel_id>(KernelIDImpl);
 
-        It = m_KernelName2KernelIDs.emplace_hint(It, EntriesIt->name, KernelID);
+        It = m_KernelName2KernelIDs.emplace_hint(It, name, KernelID);
       }
       m_KernelIDs2BinImage.insert(std::make_pair(It->second, Img.get()));
       m_BinImg2KernelIDs[Img.get()]->push_back(It->second);
@@ -2020,25 +2021,25 @@ void ProgramManager::removeImages(sycl_device_binaries DeviceBinary) {
 
     // Unmap the unique kernel IDs for the offload entries
     for (sycl_offload_entry EntriesIt = EntriesB; EntriesIt != EntriesE;
-         ++EntriesIt) {
+         EntriesIt = EntriesIt->Increment()) {
 
       // Drop entry for service kernel
-      if (std::strstr(EntriesIt->name, "__sycl_service_kernel__")) {
-        m_ServiceKernels.erase(EntriesIt->name);
+      if (std::strstr(EntriesIt->GetName(), "__sycl_service_kernel__")) {
+        m_ServiceKernels.erase(EntriesIt->GetName());
         continue;
       }
 
       // Exported device functions won't have a kernel ID
-      if (m_ExportedSymbolImages.find(EntriesIt->name) !=
+      if (m_ExportedSymbolImages.find(EntriesIt->GetName()) !=
           m_ExportedSymbolImages.end()) {
         continue;
       }
 
       // remove everything associated with this KernelName
-      m_KernelUsesAssert.erase(EntriesIt->name);
-      m_KernelImplicitLocalArgPos.erase(EntriesIt->name);
+      m_KernelUsesAssert.erase(EntriesIt->GetName());
+      m_KernelImplicitLocalArgPos.erase(EntriesIt->GetName());
 
-      if (auto It = m_KernelName2KernelIDs.find(EntriesIt->name);
+      if (auto It = m_KernelName2KernelIDs.find(EntriesIt->GetName());
           It != m_KernelName2KernelIDs.end()) {
         m_KernelName2KernelIDs.erase(It);
         m_KernelIDs2BinImage.erase(It->second);

sycl/unittests/kernel-and-program/PersistentDeviceCodeCache.cpp

@@ -336,8 +336,8 @@ TEST_P(PersistentDeviceCodeCache, MultipleImages) {
   std::sort(Imgs.begin(), Imgs.end(),
             [](const detail::RTDeviceBinaryImage *A,
                const detail::RTDeviceBinaryImage *B) {
-              return std::strcmp(A->getRawData().EntriesBegin->name,
-                                 B->getRawData().EntriesBegin->name) < 0;
+              return std::strcmp(A->getRawData().EntriesBegin->GetName(),
+                                 B->getRawData().EntriesBegin->GetName()) < 0;
             });
   std::string ItemDir = detail::PersistentDeviceCodeCache::getCacheItemPath(
       Dev, Imgs, {}, BuildOptions);