[Offload] Introduce ATTACH map-type support for pointer attachment.

offload/include/OpenMP/Mapping.h

@@ -417,12 +417,42 @@ struct MapperComponentsTy {
 typedef void (*MapperFuncPtrTy)(void *, void *, void *, int64_t, int64_t,
                                 void *);
 
+/// Structure to store information about a single ATTACH map entry.
+struct AttachMapInfo {
+  void *PointerBase;
+  void *PointeeBegin;
+  int64_t PointerSize;
+  int64_t MapType;
+  map_var_info_t Pointername;
+
+  AttachMapInfo(void *PointerBase, void *PointeeBegin, int64_t Size,
+                int64_t Type, map_var_info_t Name)
+      : PointerBase(PointerBase), PointeeBegin(PointeeBegin), PointerSize(Size),
+        MapType(Type), Pointername(Name) {}
+};
+
+/// Structure to track ATTACH entries and new allocations across recursive calls
+/// (for handling mappers) to targetDataBegin for a given construct.
+struct AttachInfoTy {
+  /// ATTACH map entries for deferred processing.
+  llvm::SmallVector<AttachMapInfo> AttachEntries;
+
+  /// Key: host pointer, Value: allocation size.
+  llvm::DenseMap<void *, int64_t> NewAllocations;
+
+  AttachInfoTy() = default;
+
+  // Delete copy constructor and copy assignment operator to prevent copying
+  AttachInfoTy(const AttachInfoTy &) = delete;
+  AttachInfoTy &operator=(const AttachInfoTy &) = delete;
+};
+
 // Function pointer type for targetData* functions (targetDataBegin,
 // targetDataEnd and targetDataUpdate).
 typedef int (*TargetDataFuncPtrTy)(ident_t *, DeviceTy &, int32_t, void **,
                                    void **, int64_t *, int64_t *,
                                    map_var_info_t *, void **, AsyncInfoTy &,
-                                   bool);
+                                   AttachInfoTy *, bool);
 
 void dumpTargetPointerMappings(const ident_t *Loc, DeviceTy &Device,
                                bool toStdOut = false);
@@ -431,20 +461,26 @@ int targetDataBegin(ident_t *Loc, DeviceTy &Device, int32_t ArgNum,
                     void **ArgsBase, void **Args, int64_t *ArgSizes,
                     int64_t *ArgTypes, map_var_info_t *ArgNames,
                     void **ArgMappers, AsyncInfoTy &AsyncInfo,
+                    AttachInfoTy *AttachInfo = nullptr,
                     bool FromMapper = false);
 
 int targetDataEnd(ident_t *Loc, DeviceTy &Device, int32_t ArgNum,
                   void **ArgBases, void **Args, int64_t *ArgSizes,
                   int64_t *ArgTypes, map_var_info_t *ArgNames,
                   void **ArgMappers, AsyncInfoTy &AsyncInfo,
-                  bool FromMapper = false);
+                  AttachInfoTy *AttachInfo = nullptr, bool FromMapper = false);
 
 int targetDataUpdate(ident_t *Loc, DeviceTy &Device, int32_t ArgNum,
                      void **ArgsBase, void **Args, int64_t *ArgSizes,
                      int64_t *ArgTypes, map_var_info_t *ArgNames,
                      void **ArgMappers, AsyncInfoTy &AsyncInfo,
+                     AttachInfoTy *AttachInfo = nullptr,
                      bool FromMapper = false);
 
+// Process deferred ATTACH map entries collected during targetDataBegin.
+int processAttachEntries(DeviceTy &Device, AttachInfoTy &AttachInfo,
+                         AsyncInfoTy &AsyncInfo);
+
 struct MappingInfoTy {
   MappingInfoTy(DeviceTy &Device) : Device(Device) {}
 

offload/include/omptarget.h

@@ -80,6 +80,9 @@ enum tgt_map_type {
   // the structured region
   // This is an OpenMP extension for the sake of OpenACC support.
   OMP_TGT_MAPTYPE_OMPX_HOLD       = 0x2000,
+  // Attach pointer and pointee, after processing all other maps.
+  // Applicable to map-entering directives. Does not change ref-count.
+  OMP_TGT_MAPTYPE_ATTACH          = 0x4000,
   // descriptor for non-contiguous target-update
   OMP_TGT_MAPTYPE_NON_CONTIG      = 0x100000000000,
   // member of struct, member given by [16 MSBs] - 1

offload/libomptarget/interface.cpp

@@ -165,12 +165,27 @@ targetData(ident_t *Loc, int64_t DeviceId, int32_t ArgNum, void **ArgsBase,
                                              OMPT_GET_RETURN_ADDRESS);)
 
   int Rc = OFFLOAD_SUCCESS;
+
+  // Only allocate AttachInfo for targetDataBegin
+  AttachInfoTy *AttachInfo = nullptr;
+  if (TargetDataFunction == targetDataBegin)
+    AttachInfo = new AttachInfoTy();
+
   Rc = TargetDataFunction(Loc, *DeviceOrErr, ArgNum, ArgsBase, Args, ArgSizes,
-                          ArgTypes, ArgNames, ArgMappers, AsyncInfo,
-                          false /*FromMapper=*/);
+                          ArgTypes, ArgNames, ArgMappers, AsyncInfo, AttachInfo,
+                          /*FromMapper=*/false);
 
-  if (Rc == OFFLOAD_SUCCESS)
-    Rc = AsyncInfo.synchronize();
+  if (Rc == OFFLOAD_SUCCESS) {
+    // Process deferred ATTACH entries BEFORE synchronization
+    if (AttachInfo && !AttachInfo->AttachEntries.empty())
+      Rc = processAttachEntries(*DeviceOrErr, *AttachInfo, AsyncInfo);
+
+    if (Rc == OFFLOAD_SUCCESS)
+      Rc = AsyncInfo.synchronize();
+  }
+
+  if (AttachInfo)
+    delete AttachInfo;
 
   handleTargetOutcome(Rc == OFFLOAD_SUCCESS, Loc);
 }