[OpenMP][OpenMPIRBuilder] Migrate loadOffloadInfoMetadata from clang to OMPIRbuilder

[TIFitis]

Summary

This patch moves the implementation of the loadOffloadInfoMetadata to the OMPIRbuilder.

[jdoerfert]

llvm/include/llvm/Frontend/OpenMP/OMPIRBuilder.h

2180

Why is this in llvm namespace? This should be qualified further, e.g. part of the OMPIRBuilder. Also, no llvm::

llvm/lib/Frontend/OpenMP/OMPIRBuilder.cpp

4717

Why do we call it if isDevice is false? Module should be available to the IRBuilder.

4765

No llvm::. Put "omp_offload.info" into a global constant, either in OMPIRBuilder or OMPConstants.

[TIFitis]

Moved loadOffloadInfoMetadata inside OpenMPIRBuilder class.

[TIFitis]

llvm/lib/Frontend/OpenMP/OMPIRBuilder.cpp

4717

loadOffloadInfoMetadata is called from clang with a different Module generated using parseBitcodeFile. I've checked that the module available from OMPIRBuilder and the one passed by clang are different and cause errors.

[jdoerfert]

@jsjodin Can you take a look and accept once it looks ok.

llvm/lib/Frontend/OpenMP/OMPIRBuilder.cpp

4717

I see. Then document this explicitly in the doxygen comment of the declaration, please. Also check isDevice at the call site.

[TIFitis]

Added doxygen comment to explain why module must be passed to OMPIRBuilder.

[TIFitis]

llvm/lib/Frontend/OpenMP/OMPIRBuilder.cpp

4717

Added doxygen comment. isDevice is checked at call site through CGM.getLangOpts().OpenMPIsDevice.

[TIFitis]

Removed isDevice() check from function definition.

[TIFitis]

Fix build errors

[jsjodin]

llvm/lib/Frontend/OpenMP/OMPIRBuilder.cpp

4712

isDevice must be true (add assertion at the call site) remove the parameter, and the assertions in this function. Document that this function is only intended to be used with device code generation.

[jdoerfert]

llvm/include/llvm/Frontend/OpenMP/OMPIRBuilder.h

1685

Drive by, add doxygen documentation to all methods + members please.

[TIFitis]

Removed isDevice from parameters. Added documentation.

[TIFitis]

llvm/lib/Frontend/OpenMP/OMPIRBuilder.cpp

4712

I've removed isDevice as a parameter. At the call site, isDevice is checked inside an if condition and it returns on false, thus I haven't added the assertion back at the call site.

[TIFitis]

Fixed comments

[jsjodin]

@jdoerfert do you have any other comments?

clang/lib/CodeGen/CGOpenMPRuntime.cpp

void CGOpenMPRuntime::loadOffloadInfoMetadata() {
   if (auto EC = ME.getError()) {
     unsigned DiagID = CGM.getDiags().getCustomDiagID(
         DiagnosticsEngine::Error, "Unable to parse host IR file '%0':'%1'");
     CGM.getDiags().Report(DiagID)
         << CGM.getLangOpts().OMPHostIRFile << EC.message();
     return;
   }
 
-  llvm::NamedMDNode *MD = ME.get()->getNamedMetadata("omp_offload.info");
-  if (!MD)
-    return;
-
-  for (llvm::MDNode *MN : MD->operands()) {
-    auto &&GetMDInt = [MN](unsigned Idx) {
-      auto *V = cast<llvm::ConstantAsMetadata>(MN->getOperand(Idx));
-      return cast<llvm::ConstantInt>(V->getValue())->getZExtValue();
-    };
-
-    auto &&GetMDString = [MN](unsigned Idx) {
-      auto *V = cast<llvm::MDString>(MN->getOperand(Idx));
-      return V->getString();
-    };
-
-    switch (GetMDInt(0)) {
-    default:
-      llvm_unreachable("Unexpected metadata!");
-      break;
-    case llvm::OffloadEntriesInfoManager::OffloadEntryInfo::
-        OffloadingEntryInfoTargetRegion: {
-      assert(CGM.getLangOpts().OpenMPIsDevice && "Initialization of entries is "
-                                                 "only required for the "
-                                                 "device code generation.");
-      llvm::TargetRegionEntryInfo EntryInfo(/*ParentName=*/GetMDString(3),
-                                            /*DeviceID=*/GetMDInt(1),
-                                            /*FileID=*/GetMDInt(2),
-                                            /*Line=*/GetMDInt(4));
-      OffloadEntriesInfoManager.initializeTargetRegionEntryInfo(
-          EntryInfo, /*Order=*/GetMDInt(5));
-      break;
-    }
-    case llvm::OffloadEntriesInfoManager::OffloadEntryInfo::
-        OffloadingEntryInfoDeviceGlobalVar:
-      assert(CGM.getLangOpts().OpenMPIsDevice && "Initialization of entries is "
-                                                 "only required for the "
-                                                 "device code generation.");
-      OffloadEntriesInfoManager.initializeDeviceGlobalVarEntryInfo(
-          /*MangledName=*/GetMDString(1),
-          static_cast<
-              llvm::OffloadEntriesInfoManager::OMPTargetGlobalVarEntryKind>(
-              /*Flags=*/GetMDInt(2)),
-          /*Order=*/GetMDInt(3));
-      break;
-    }
-  }
+  OMPBuilder.loadOffloadInfoMetadata(*ME.get(), OffloadEntriesInfoManager);
 }
 
 void CGOpenMPRuntime::emitKmpRoutineEntryT(QualType KmpInt32Ty) {
   if (!KmpRoutineEntryPtrTy) {
     // Build typedef kmp_int32 (* kmp_routine_entry_t)(kmp_int32, void *); type.
     ASTContext &C = CGM.getContext();
     QualType KmpRoutineEntryTyArgs[] = {KmpInt32Ty, C.VoidPtrTy};
     FunctionProtoType::ExtProtoInfo EPI;

llvm/include/llvm/Frontend/OpenMP/OMPIRBuilder.h

public:
   ///                  and instruction names.
   ///
   /// \returns The CanonicalLoopInfo that represents the emitted loop.
   CanonicalLoopInfo *createLoopSkeleton(DebugLoc DL, Value *TripCount,
                                         Function *F,
                                         BasicBlock *PreInsertBefore,
                                         BasicBlock *PostInsertBefore,
                                         const Twine &Name = {});
+  /// OMP Offload Info Metadata name string
+  const std::string ompOffloadInfoName = "omp_offload.info";
+
+  /// Loads all the offload entries information from the host IR
+  /// metadata. This function is only meant to be used with device code
+  /// generation.
+  ///
+  /// \param M         Module to load Metadata info from. Module passed maybe
+  /// loaded from bitcode file, i.e, different from OpenMPIRBuilder::M module.
+  /// \param OffloadEntriesInfoManager Initialize Offload Entry information.
+  void
+  loadOffloadInfoMetadata(Module &M,
+                          OffloadEntriesInfoManager &OffloadEntriesInfoManager);
 };
 
 /// Data structure to contain the information needed to uniquely identify
 /// a target entry.
 struct TargetRegionEntryInfo {
   std::string ParentName;
   unsigned DeviceID;
   unsigned FileID;
public:
 
   /// Invalidate this loop. That is, the underlying IR does not fulfill the
   /// requirements of an OpenMP canonical loop anymore.
   void invalidate();
 };
 
 } // end namespace llvm
 
 #endif // LLVM_FRONTEND_OPENMP_OMPIRBUILDER_H

llvm/lib/Frontend/OpenMP/OMPIRBuilder.cpp

OS << "__omp_offloading" << llvm::format("_%x", DeviceID)
      << llvm::format("_%x_", FileID) << ParentName << "_l" << Line;
 }
 
 void TargetRegionEntryInfo::getTargetRegionEntryFnName(
     SmallVectorImpl<char> &Name) {
   getTargetRegionEntryFnName(Name, ParentName, DeviceID, FileID, Line);
 }
 
+/// Loads all the offload entries information from the host IR
+/// metadata.
+void OpenMPIRBuilder::loadOffloadInfoMetadata(
+    Module &M, OffloadEntriesInfoManager &OffloadEntriesInfoManager) {
+  // If we are in target mode, load the metadata from the host IR. This code has
+  // to match the metadata creation in createOffloadEntriesAndInfoMetadata().
+
+  NamedMDNode *MD = M.getNamedMetadata(ompOffloadInfoName);
+  if (!MD)
+    return;
+
+  for (MDNode *MN : MD->operands()) {
+    auto &&GetMDInt = [MN](unsigned Idx) {
+      auto *V = cast<ConstantAsMetadata>(MN->getOperand(Idx));
+      return cast<ConstantInt>(V->getValue())->getZExtValue();
+    };
+
+    auto &&GetMDString = [MN](unsigned Idx) {
+      auto *V = cast<MDString>(MN->getOperand(Idx));
+      return V->getString();
+    };
+
+    switch (GetMDInt(0)) {
+    default:
+      llvm_unreachable("Unexpected metadata!");
+      break;
+    case OffloadEntriesInfoManager::OffloadEntryInfo::
+        OffloadingEntryInfoTargetRegion: {
+      TargetRegionEntryInfo EntryInfo(/*ParentName=*/GetMDString(3),
+                                      /*DeviceID=*/GetMDInt(1),
+                                      /*FileID=*/GetMDInt(2),
+                                      /*Line=*/GetMDInt(4));
+      OffloadEntriesInfoManager.initializeTargetRegionEntryInfo(
+          EntryInfo, /*Order=*/GetMDInt(5));
+      break;
+    }
+    case OffloadEntriesInfoManager::OffloadEntryInfo::
+        OffloadingEntryInfoDeviceGlobalVar:
+      OffloadEntriesInfoManager.initializeDeviceGlobalVarEntryInfo(
+          /*MangledName=*/GetMDString(1),
+          static_cast<OffloadEntriesInfoManager::OMPTargetGlobalVarEntryKind>(
+              /*Flags=*/GetMDInt(2)),
+          /*Order=*/GetMDInt(3));
+      break;
+    }
+  }
+}
+
 bool OffloadEntriesInfoManager::empty() const {
   return OffloadEntriesTargetRegion.empty() &&
          OffloadEntriesDeviceGlobalVar.empty();
 }
 
 /// Initialize target region entry.
 void OffloadEntriesInfoManager::initializeTargetRegionEntryInfo(
     const TargetRegionEntryInfo &EntryInfo, unsigned Order) {
   OffloadEntriesTargetRegion[EntryInfo] =
       OffloadEntryInfoTargetRegion(Order, /*Addr=*/nullptr, /*ID=*/nullptr,
                                    OMPTargetRegionEntryTargetRegion);
   ++OffloadingEntriesNum;
 }
 
 void OffloadEntriesInfoManager::registerTargetRegionEntryInfo(
     const TargetRegionEntryInfo &EntryInfo, Constant *Addr, Constant *ID,
     OMPTargetRegionEntryKind Flags, bool IsDevice) {
   // If we are emitting code for a target, the entry is already initialized,