[mlir] Add global and program memory space handling to the data layout subsystem (#77367)

This patch is based on a previous PR https://reviews.llvm.org/D144657
that added alloca address space handling to MLIR's DataLayout and DLTI
interface. This patch aims to add identical features to import and
access the global and program memory space through MLIR's
DataLayout/DLTI system.

Author: agozillon

mlir/include/mlir/Dialect/DLTI/DLTI.h

@@ -103,6 +103,12 @@ class DataLayoutSpecAttr
   /// Returns the alloca memory space identifier.
   StringAttr getAllocaMemorySpaceIdentifier(MLIRContext *context) const;
 
+  /// Returns the program memory space identifier.
+  StringAttr getProgramMemorySpaceIdentifier(MLIRContext *context) const;
+
+  /// Returns the global memory space identifier.
+  StringAttr getGlobalMemorySpaceIdentifier(MLIRContext *context) const;
+
   /// Returns the stack alignment identifier.
   StringAttr getStackAlignmentIdentifier(MLIRContext *context) const;
 

mlir/include/mlir/Dialect/DLTI/DLTIBase.td

@@ -39,6 +39,12 @@ def DLTI_Dialect : Dialect {
 
     constexpr const static ::llvm::StringLiteral
     kDataLayoutAllocaMemorySpaceKey = "dlti.alloca_memory_space";
+    
+    constexpr const static ::llvm::StringLiteral
+    kDataLayoutProgramMemorySpaceKey = "dlti.program_memory_space";
+
+    constexpr const static ::llvm::StringLiteral
+    kDataLayoutGlobalMemorySpaceKey = "dlti.global_memory_space";
 
     constexpr const static ::llvm::StringLiteral
     kDataLayoutStackAlignmentKey = "dlti.stack_alignment";

mlir/include/mlir/Interfaces/DataLayoutInterfaces.h

@@ -61,6 +61,14 @@ getDefaultPreferredAlignment(Type type, const DataLayout &dataLayout,
 /// DataLayoutInterface if specified, otherwise returns the default.
 Attribute getDefaultAllocaMemorySpace(DataLayoutEntryInterface entry);
 
+/// Default handler for program memory space request. Dispatches to the
+/// DataLayoutInterface if specified, otherwise returns the default.
+Attribute getDefaultProgramMemorySpace(DataLayoutEntryInterface entry);
+
+/// Default handler for global memory space request. Dispatches to the
+/// DataLayoutInterface if specified, otherwise returns the default.
+Attribute getDefaultGlobalMemorySpace(DataLayoutEntryInterface entry);
+
 /// Default handler for the stack alignment request. Dispatches to the
 /// DataLayoutInterface if specified, otherwise returns the default.
 uint64_t getDefaultStackAlignment(DataLayoutEntryInterface entry);
@@ -175,6 +183,12 @@ class DataLayout {
   /// Returns the memory space used for AllocaOps.
   Attribute getAllocaMemorySpace() const;
 
+  /// Returns the memory space used for program memory operations.
+  Attribute getProgramMemorySpace() const;
+
+  /// Returns the memory space used for global operations.
+  Attribute getGlobalMemorySpace() const;
+
   /// Returns the natural alignment of the stack in bits. Alignment promotion of
   /// stack variables should be limited to the natural stack alignment to
   /// prevent dynamic stack alignment. Returns zero if the stack alignment is
@@ -203,8 +217,10 @@ class DataLayout {
   mutable DenseMap<Type, uint64_t> abiAlignments;
   mutable DenseMap<Type, uint64_t> preferredAlignments;
 
-  /// Cache for alloca memory space.
+  /// Cache for alloca, global, and program memory spaces.
   mutable std::optional<Attribute> allocaMemorySpace;
+  mutable std::optional<Attribute> programMemorySpace;
+  mutable std::optional<Attribute> globalMemorySpace;
 
   /// Cache for stack alignment.
   mutable std::optional<uint64_t> stackAlignment;

mlir/include/mlir/Interfaces/DataLayoutInterfaces.td

@@ -112,6 +112,18 @@ def DataLayoutSpecInterface : AttrInterface<"DataLayoutSpecInterface"> {
       /*methodName=*/"getAllocaMemorySpaceIdentifier",
       /*args=*/(ins "::mlir::MLIRContext *":$context)
     >,
+    InterfaceMethod<
+      /*description=*/"Returns the program memory space identifier.",
+      /*retTy=*/"::mlir::StringAttr",
+      /*methodName=*/"getProgramMemorySpaceIdentifier",
+      /*args=*/(ins "::mlir::MLIRContext *":$context)
+    >,
+    InterfaceMethod<
+      /*description=*/"Returns the global memory space identifier.",
+      /*retTy=*/"::mlir::StringAttr",
+      /*methodName=*/"getGlobalMemorySpaceIdentifier",
+      /*args=*/(ins "::mlir::MLIRContext *":$context)
+    >,
     InterfaceMethod<
       /*description=*/"Returns the stack alignment identifier.",
       /*retTy=*/"::mlir::StringAttr",
@@ -280,6 +292,30 @@ def DataLayoutOpInterface : OpInterface<"DataLayoutOpInterface"> {
         return ::mlir::detail::getDefaultAllocaMemorySpace(entry);
       }]
     >,
+    StaticInterfaceMethod<
+      /*description=*/"Returns the memory space used by the ABI computed "
+                      "using the relevant entries. The data layout object "
+                      "can be used for recursive queries.",
+      /*retTy=*/"::mlir::Attribute",
+      /*methodName=*/"getProgramMemorySpace",
+      /*args=*/(ins "::mlir::DataLayoutEntryInterface":$entry),
+      /*methodBody=*/"",
+      /*defaultImplementation=*/[{
+        return ::mlir::detail::getDefaultProgramMemorySpace(entry);
+      }]
+    >,
+    StaticInterfaceMethod<
+      /*description=*/"Returns the memory space used by the ABI computed "
+                      "using the relevant entries. The data layout object "
+                      "can be used for recursive queries.",
+      /*retTy=*/"::mlir::Attribute",
+      /*methodName=*/"getGlobalMemorySpace",
+      /*args=*/(ins "::mlir::DataLayoutEntryInterface":$entry),
+      /*methodBody=*/"",
+      /*defaultImplementation=*/[{
+        return ::mlir::detail::getDefaultGlobalMemorySpace(entry);
+      }]
+    >,
     StaticInterfaceMethod<
       /*description=*/"Returns the natural stack alignment in bits computed "
                       "using the relevant entries. The data layout object "

mlir/lib/Dialect/DLTI/DLTI.cpp

@@ -108,6 +108,11 @@ void DataLayoutEntryAttr::print(AsmPrinter &os) const {
 constexpr const StringLiteral mlir::DataLayoutSpecAttr::kAttrKeyword;
 constexpr const StringLiteral
     mlir::DLTIDialect::kDataLayoutAllocaMemorySpaceKey;
+constexpr const StringLiteral
+    mlir::DLTIDialect::kDataLayoutProgramMemorySpaceKey;
+constexpr const StringLiteral
+    mlir::DLTIDialect::kDataLayoutGlobalMemorySpaceKey;
+
 constexpr const StringLiteral mlir::DLTIDialect::kDataLayoutStackAlignmentKey;
 
 namespace mlir {
@@ -282,6 +287,17 @@ DataLayoutSpecAttr::getAllocaMemorySpaceIdentifier(MLIRContext *context) const {
       DLTIDialect::kDataLayoutAllocaMemorySpaceKey);
 }
 
+StringAttr DataLayoutSpecAttr::getProgramMemorySpaceIdentifier(
+    MLIRContext *context) const {
+  return Builder(context).getStringAttr(
+      DLTIDialect::kDataLayoutProgramMemorySpaceKey);
+}
+
+StringAttr
+DataLayoutSpecAttr::getGlobalMemorySpaceIdentifier(MLIRContext *context) const {
+  return Builder(context).getStringAttr(
+      DLTIDialect::kDataLayoutGlobalMemorySpaceKey);
+}
 StringAttr
 DataLayoutSpecAttr::getStackAlignmentIdentifier(MLIRContext *context) const {
   return Builder(context).getStringAttr(
@@ -345,6 +361,8 @@ class TargetDataLayoutInterface : public DataLayoutDialectInterface {
                             << DLTIDialect::kDataLayoutEndiannessLittle << "'";
     }
     if (entryName == DLTIDialect::kDataLayoutAllocaMemorySpaceKey ||
+        entryName == DLTIDialect::kDataLayoutProgramMemorySpaceKey ||
+        entryName == DLTIDialect::kDataLayoutGlobalMemorySpaceKey ||
         entryName == DLTIDialect::kDataLayoutStackAlignmentKey)
       return success();
     return emitError(loc) << "unknown data layout entry name: " << entryName;

mlir/lib/Interfaces/DataLayoutInterfaces.cpp

@@ -230,6 +230,30 @@ mlir::detail::getDefaultAllocaMemorySpace(DataLayoutEntryInterface entry) {
   return entry.getValue();
 }
 
+// Returns the memory space used for the program memory space.  if
+// specified in the given entry. If the entry is empty the default
+// memory space represented by an empty attribute is returned.
+Attribute
+mlir::detail::getDefaultProgramMemorySpace(DataLayoutEntryInterface entry) {
+  if (entry == DataLayoutEntryInterface()) {
+    return Attribute();
+  }
+
+  return entry.getValue();
+}
+
+// Returns the memory space used for global the global memory space. if
+// specified in the given entry. If the entry is empty the default memory
+// space represented by an empty attribute is returned.
+Attribute
+mlir::detail::getDefaultGlobalMemorySpace(DataLayoutEntryInterface entry) {
+  if (entry == DataLayoutEntryInterface()) {
+    return Attribute();
+  }
+
+  return entry.getValue();
+}
+
 // Returns the stack alignment if specified in the given entry. If the entry is
 // empty the default alignment zero is returned.
 uint64_t
@@ -382,7 +406,8 @@ mlir::DataLayout::DataLayout() : DataLayout(ModuleOp()) {}
 
 mlir::DataLayout::DataLayout(DataLayoutOpInterface op)
     : originalLayout(getCombinedDataLayout(op)), scope(op),
-      allocaMemorySpace(std::nullopt), stackAlignment(std::nullopt) {
+      allocaMemorySpace(std::nullopt), programMemorySpace(std::nullopt),
+      globalMemorySpace(std::nullopt), stackAlignment(std::nullopt) {
 #if LLVM_ENABLE_ABI_BREAKING_CHECKS
   checkMissingLayout(originalLayout, op);
   collectParentLayouts(op, layoutStack);
@@ -391,7 +416,8 @@ mlir::DataLayout::DataLayout(DataLayoutOpInterface op)
 
 mlir::DataLayout::DataLayout(ModuleOp op)
     : originalLayout(getCombinedDataLayout(op)), scope(op),
-      allocaMemorySpace(std::nullopt), stackAlignment(std::nullopt) {
+      allocaMemorySpace(std::nullopt), programMemorySpace(std::nullopt),
+      globalMemorySpace(std::nullopt), stackAlignment(std::nullopt) {
 #if LLVM_ENABLE_ABI_BREAKING_CHECKS
   checkMissingLayout(originalLayout, op);
   collectParentLayouts(op, layoutStack);
@@ -510,6 +536,38 @@ mlir::Attribute mlir::DataLayout::getAllocaMemorySpace() const {
   return *allocaMemorySpace;
 }
 
+mlir::Attribute mlir::DataLayout::getProgramMemorySpace() const {
+  checkValid();
+  if (programMemorySpace)
+    return *programMemorySpace;
+  DataLayoutEntryInterface entry;
+  if (originalLayout)
+    entry = originalLayout.getSpecForIdentifier(
+        originalLayout.getProgramMemorySpaceIdentifier(
+            originalLayout.getContext()));
+  if (auto iface = dyn_cast_or_null<DataLayoutOpInterface>(scope))
+    programMemorySpace = iface.getProgramMemorySpace(entry);
+  else
+    programMemorySpace = detail::getDefaultProgramMemorySpace(entry);
+  return *programMemorySpace;
+}
+
+mlir::Attribute mlir::DataLayout::getGlobalMemorySpace() const {
+  checkValid();
+  if (globalMemorySpace)
+    return *globalMemorySpace;
+  DataLayoutEntryInterface entry;
+  if (originalLayout)
+    entry = originalLayout.getSpecForIdentifier(
+        originalLayout.getGlobalMemorySpaceIdentifier(
+            originalLayout.getContext()));
+  if (auto iface = dyn_cast_or_null<DataLayoutOpInterface>(scope))
+    globalMemorySpace = iface.getGlobalMemorySpace(entry);
+  else
+    globalMemorySpace = detail::getDefaultGlobalMemorySpace(entry);
+  return *globalMemorySpace;
+}
+
 uint64_t mlir::DataLayout::getStackAlignment() const {
   checkValid();
   if (stackAlignment)

mlir/lib/Target/LLVMIR/DataLayoutImporter.cpp

@@ -164,9 +164,9 @@ DataLayoutImporter::tryToEmplaceEndiannessEntry(StringRef endianness,
 }
 
 LogicalResult
-DataLayoutImporter::tryToEmplaceAllocaAddrSpaceEntry(StringRef token) {
-  auto key =
-      StringAttr::get(context, DLTIDialect::kDataLayoutAllocaMemorySpaceKey);
+DataLayoutImporter::tryToEmplaceAddrSpaceEntry(StringRef token,
+                                               llvm::StringLiteral spaceKey) {
+  auto key = StringAttr::get(context, spaceKey);
   if (keyEntries.count(key))
     return success();
 
@@ -247,9 +247,24 @@ void DataLayoutImporter::translateDataLayout(
         return;
       continue;
     }
+    // Parse the program address space.
+    if (*prefix == "P") {
+      if (failed(tryToEmplaceAddrSpaceEntry(
+              token, DLTIDialect::kDataLayoutProgramMemorySpaceKey)))
+        return;
+      continue;
+    }
+    // Parse the global address space.
+    if (*prefix == "G") {
+      if (failed(tryToEmplaceAddrSpaceEntry(
+              token, DLTIDialect::kDataLayoutGlobalMemorySpaceKey)))
+        return;
+      continue;
+    }
     // Parse the alloca address space.
     if (*prefix == "A") {
-      if (failed(tryToEmplaceAllocaAddrSpaceEntry(token)))
+      if (failed(tryToEmplaceAddrSpaceEntry(
+              token, DLTIDialect::kDataLayoutAllocaMemorySpaceKey)))
         return;
       continue;
     }

mlir/lib/Target/LLVMIR/DataLayoutImporter.h

@@ -97,7 +97,8 @@ class DataLayoutImporter {
                                             StringRef token);
 
   /// Adds an alloca address space entry if there is none yet.
-  LogicalResult tryToEmplaceAllocaAddrSpaceEntry(StringRef token);
+  LogicalResult tryToEmplaceAddrSpaceEntry(StringRef token,
+                                           llvm::StringLiteral spaceKey);
 
   /// Adds a stack alignment entry if there is none yet.
   LogicalResult tryToEmplaceStackAlignmentEntry(StringRef token);

mlir/lib/Target/LLVMIR/ModuleTranslation.cpp

@@ -190,6 +190,26 @@ translateDataLayout(DataLayoutSpecInterface attribute,
       layoutStream.flush();
       continue;
     }
+    if (key.getValue() == DLTIDialect::kDataLayoutProgramMemorySpaceKey) {
+      auto value = cast<IntegerAttr>(entry.getValue());
+      uint64_t space = value.getValue().getZExtValue();
+      // Skip the default address space.
+      if (space == 0)
+        continue;
+      layoutStream << "-P" << space;
+      layoutStream.flush();
+      continue;
+    }
+    if (key.getValue() == DLTIDialect::kDataLayoutGlobalMemorySpaceKey) {
+      auto value = cast<IntegerAttr>(entry.getValue());
+      uint64_t space = value.getValue().getZExtValue();
+      // Skip the default address space.
+      if (space == 0)
+        continue;
+      layoutStream << "-G" << space;
+      layoutStream.flush();
+      continue;
+    }
     if (key.getValue() == DLTIDialect::kDataLayoutAllocaMemorySpaceKey) {
       auto value = cast<IntegerAttr>(entry.getValue());
       uint64_t space = value.getValue().getZExtValue();