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@Jezurko Jezurko commented Jul 9, 2025

Add IFunc to LLVM dialect and add support for lifting/exporting LLVMIR IFunc.

Add IFunc to LLVM dialect and add support for lifting/exporting LLVMIR
IFunc.
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llvmbot commented Jul 9, 2025

@llvm/pr-subscribers-mlir-llvm

@llvm/pr-subscribers-mlir

Author: Robert Konicar (Jezurko)

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Add IFunc to LLVM dialect and add support for lifting/exporting LLVMIR IFunc.


Patch is 31.51 KiB, truncated to 20.00 KiB below, full version: https://github.com/llvm/llvm-project/pull/147697.diff

10 Files Affected:

  • (modified) mlir/include/mlir/Dialect/LLVMIR/LLVMDialect.h (+3)
  • (modified) mlir/include/mlir/Dialect/LLVMIR/LLVMOps.td (+40)
  • (modified) mlir/include/mlir/Target/LLVMIR/ModuleImport.h (+5)
  • (modified) mlir/include/mlir/Target/LLVMIR/ModuleTranslation.h (+9)
  • (modified) mlir/lib/Dialect/LLVMIR/IR/LLVMDialect.cpp (+88-18)
  • (modified) mlir/lib/Target/LLVMIR/Dialect/LLVMIR/LLVMToLLVMIRTranslation.cpp (+18-6)
  • (modified) mlir/lib/Target/LLVMIR/ModuleImport.cpp (+43-6)
  • (modified) mlir/lib/Target/LLVMIR/ModuleTranslation.cpp (+27-1)
  • (added) mlir/test/Target/LLVMIR/Import/ifunc.ll (+115)
  • (added) mlir/test/Target/LLVMIR/ifunc.mlir (+123)
diff --git a/mlir/include/mlir/Dialect/LLVMIR/LLVMDialect.h b/mlir/include/mlir/Dialect/LLVMIR/LLVMDialect.h
index 63e007cdc335c..e355bb8f5ddae 100644
--- a/mlir/include/mlir/Dialect/LLVMIR/LLVMDialect.h
+++ b/mlir/include/mlir/Dialect/LLVMIR/LLVMDialect.h
@@ -223,6 +223,9 @@ Value createGlobalString(Location loc, OpBuilder &builder, StringRef name,
 /// function confirms that the Operation has the desired properties.
 bool satisfiesLLVMModule(Operation *op);
 
+/// Lookup parent Module satisfying LLVM conditions on the Module Operation.
+Operation *parentLLVMModule(Operation *op);
+
 /// Convert an array of integer attributes to a vector of integers that can be
 /// used as indices in LLVM operations.
 template <typename IntT = int64_t>
diff --git a/mlir/include/mlir/Dialect/LLVMIR/LLVMOps.td b/mlir/include/mlir/Dialect/LLVMIR/LLVMOps.td
index f4c1640098320..fe1418b12b90a 100644
--- a/mlir/include/mlir/Dialect/LLVMIR/LLVMOps.td
+++ b/mlir/include/mlir/Dialect/LLVMIR/LLVMOps.td
@@ -1285,6 +1285,10 @@ def LLVM_AddressOfOp : LLVM_Op<"mlir.addressof",
     /// Return the llvm.mlir.alias operation that defined the value referenced
     /// here.
     AliasOp getAlias(SymbolTableCollection &symbolTable);
+
+    /// Return the llvm.mlir.ifunc operation that defined the value referenced
+    /// here.
+    IFuncOp getIFunc(SymbolTableCollection &symbolTable);
   }];
 
   let assemblyFormat = "$global_name attr-dict `:` qualified(type($res))";
@@ -1601,6 +1605,42 @@ def LLVM_AliasOp : LLVM_Op<"mlir.alias",
   let hasRegionVerifier = 1;
 }
 
+def LLVM_IFuncOp : LLVM_Op<"mlir.ifunc",
+    [IsolatedFromAbove, Symbol, DeclareOpInterfaceMethods<SymbolUserOpInterface>]> {
+  let arguments = (ins
+    SymbolNameAttr:$sym_name,
+    TypeAttr:$i_func_type,
+    FlatSymbolRefAttr:$resolver,
+    TypeAttr:$resolver_type,
+    UnitAttr:$dso_local,
+    DefaultValuedAttr<ConfinedAttr<I32Attr, [IntNonNegative]>, "0">:$address_space,
+    DefaultValuedAttr<Linkage, "mlir::LLVM::Linkage::External">:$linkage,
+    DefaultValuedAttr<UnnamedAddr, "mlir::LLVM::UnnamedAddr::None">:$unnamed_addr,
+    DefaultValuedAttr<Visibility, "mlir::LLVM::Visibility::Default">:$visibility_
+  );
+  let summary = "LLVM dialect ifunc";
+  let description = [{
+    `llvm.mlir.ifunc` is a top level operation that defines a global ifunc.
+    It defines a new symbol and takes a symbol refering to a resolver function.
+    IFuncs can be called as regular functions. The function type is the same
+    as the IFuncType. The symbol is resolved at runtime by calling a resolver
+    function.
+  }];
+
+  let builders = [
+    OpBuilder<(ins "StringRef":$name, "Type":$i_func_type,
+      "StringRef":$resolver, "Type":$resolver_type,
+      "Linkage":$linkage, "LLVM::Visibility":$visibility)>
+  ];
+
+  let assemblyFormat = [{
+    (custom<LLVMLinkage>($linkage)^)? ($visibility_^)? ($unnamed_addr^)?
+    $sym_name `:` $i_func_type `,` $resolver_type $resolver attr-dict
+  }];
+  let hasVerifier = 1;
+}
+
+
 def LLVM_DSOLocalEquivalentOp : LLVM_Op<"dso_local_equivalent",
     [Pure, ConstantLike, DeclareOpInterfaceMethods<SymbolUserOpInterface>]> {
   let arguments = (ins FlatSymbolRefAttr:$function_name);
diff --git a/mlir/include/mlir/Target/LLVMIR/ModuleImport.h b/mlir/include/mlir/Target/LLVMIR/ModuleImport.h
index 9902c6bb15caf..b21600b634d2e 100644
--- a/mlir/include/mlir/Target/LLVMIR/ModuleImport.h
+++ b/mlir/include/mlir/Target/LLVMIR/ModuleImport.h
@@ -71,6 +71,9 @@ class ModuleImport {
   /// Converts all aliases of the LLVM module to MLIR variables.
   LogicalResult convertAliases();
 
+  /// Converts all ifuncs of the LLVM module to MLIR variables.
+  LogicalResult convertIFuncs();
+
   /// Converts the data layout of the LLVM module to an MLIR data layout
   /// specification.
   LogicalResult convertDataLayout();
@@ -320,6 +323,8 @@ class ModuleImport {
   /// Converts an LLVM global alias variable into an MLIR LLVM dialect alias
   /// operation if a conversion exists. Otherwise, returns failure.
   LogicalResult convertAlias(llvm::GlobalAlias *alias);
+  // Converts an LLVM global ifunc into an MLIR LLVM diaeclt ifunc operation
+  LogicalResult convertIFunc(llvm::GlobalIFunc *ifunc);
   /// Returns personality of `func` as a FlatSymbolRefAttr.
   FlatSymbolRefAttr getPersonalityAsAttr(llvm::Function *func);
   /// Imports `bb` into `block`, which must be initially empty.
diff --git a/mlir/include/mlir/Target/LLVMIR/ModuleTranslation.h b/mlir/include/mlir/Target/LLVMIR/ModuleTranslation.h
index 79e8bb6add0da..fc82be3b88395 100644
--- a/mlir/include/mlir/Target/LLVMIR/ModuleTranslation.h
+++ b/mlir/include/mlir/Target/LLVMIR/ModuleTranslation.h
@@ -223,6 +223,12 @@ class ModuleTranslation {
     return aliasesMapping.lookup(op);
   }
 
+  /// Finds an LLVM IR global value that corresponds to the given MLIR operation
+  /// defining an IFunc.
+  llvm::GlobalValue *lookupIFunc(Operation *op) {
+    return ifuncMapping.lookup(op);
+  }
+
   /// Returns the OpenMP IR builder associated with the LLVM IR module being
   /// constructed.
   llvm::OpenMPIRBuilder *getOpenMPBuilder();
@@ -308,6 +314,7 @@ class ModuleTranslation {
                                  bool recordInsertions = false);
   LogicalResult convertFunctionSignatures();
   LogicalResult convertFunctions();
+  LogicalResult convertIFuncs();
   LogicalResult convertComdats();
 
   LogicalResult convertUnresolvedBlockAddress();
@@ -369,6 +376,8 @@ class ModuleTranslation {
   /// aliases.
   DenseMap<Operation *, llvm::GlobalValue *> aliasesMapping;
 
+  DenseMap<Operation *, llvm::GlobalValue *> ifuncMapping;
+
   /// A stateful object used to translate types.
   TypeToLLVMIRTranslator typeTranslator;
 
diff --git a/mlir/lib/Dialect/LLVMIR/IR/LLVMDialect.cpp b/mlir/lib/Dialect/LLVMIR/IR/LLVMDialect.cpp
index 6dcd94e6eea17..da5a3f40faaa3 100644
--- a/mlir/lib/Dialect/LLVMIR/IR/LLVMDialect.cpp
+++ b/mlir/lib/Dialect/LLVMIR/IR/LLVMDialect.cpp
@@ -139,6 +139,17 @@ static RetTy parseOptionalLLVMKeyword(OpAsmParser &parser,
   return static_cast<RetTy>(index);
 }
 
+static void printLLVMLinkage(OpAsmPrinter &p, Operation *, LinkageAttr val) {
+  p << stringifyLinkage(val.getLinkage());
+}
+
+static OptionalParseResult parseLLVMLinkage(OpAsmParser &p, LinkageAttr &val) {
+  val = LinkageAttr::get(
+      p.getContext(),
+      parseOptionalLLVMKeyword<LLVM::Linkage>(p, LLVM::Linkage::External));
+  return success();
+}
+
 //===----------------------------------------------------------------------===//
 // Operand bundle helpers.
 //===----------------------------------------------------------------------===//
@@ -1175,14 +1186,17 @@ LogicalResult CallOp::verifySymbolUses(SymbolTableCollection &symbolTable) {
       return emitOpError()
              << "'" << calleeName.getValue()
              << "' does not reference a symbol in the current scope";
-    auto fn = dyn_cast<LLVMFuncOp>(callee);
-    if (!fn)
-      return emitOpError() << "'" << calleeName.getValue()
-                           << "' does not reference a valid LLVM function";
-
-    if (failed(verifyCallOpDebugInfo(*this, fn)))
-      return failure();
-    fnType = fn.getFunctionType();
+    if (auto fn = dyn_cast<LLVMFuncOp>(callee)) {
+      if (failed(verifyCallOpDebugInfo(*this, fn)))
+        return failure();
+      fnType = fn.getFunctionType();
+    } else if (auto ifunc = dyn_cast<IFuncOp>(callee)) {
+      fnType = ifunc.getIFuncType();
+    } else {
+      return emitOpError()
+             << "'" << calleeName.getValue()
+             << "' does not reference a valid LLVM function or IFunc";
+    }
   }
 
   LLVMFunctionType funcType = llvm::dyn_cast<LLVMFunctionType>(fnType);
@@ -2038,14 +2052,6 @@ LogicalResult ReturnOp::verify() {
 // LLVM::AddressOfOp.
 //===----------------------------------------------------------------------===//
 
-static Operation *parentLLVMModule(Operation *op) {
-  Operation *module = op->getParentOp();
-  while (module && !satisfiesLLVMModule(module))
-    module = module->getParentOp();
-  assert(module && "unexpected operation outside of a module");
-  return module;
-}
-
 GlobalOp AddressOfOp::getGlobal(SymbolTableCollection &symbolTable) {
   return dyn_cast_or_null<GlobalOp>(
       symbolTable.lookupSymbolIn(parentLLVMModule(*this), getGlobalNameAttr()));
@@ -2061,6 +2067,11 @@ AliasOp AddressOfOp::getAlias(SymbolTableCollection &symbolTable) {
       symbolTable.lookupSymbolIn(parentLLVMModule(*this), getGlobalNameAttr()));
 }
 
+IFuncOp AddressOfOp::getIFunc(SymbolTableCollection &symbolTable) {
+  return dyn_cast_or_null<IFuncOp>(
+      symbolTable.lookupSymbolIn(parentLLVMModule(*this), getGlobalNameAttr()));
+}
+
 LogicalResult
 AddressOfOp::verifySymbolUses(SymbolTableCollection &symbolTable) {
   Operation *symbol =
@@ -2069,10 +2080,11 @@ AddressOfOp::verifySymbolUses(SymbolTableCollection &symbolTable) {
   auto global = dyn_cast_or_null<GlobalOp>(symbol);
   auto function = dyn_cast_or_null<LLVMFuncOp>(symbol);
   auto alias = dyn_cast_or_null<AliasOp>(symbol);
+  auto ifunc = dyn_cast_or_null<IFuncOp>(symbol);
 
-  if (!global && !function && !alias)
+  if (!global && !function && !alias && !ifunc)
     return emitOpError("must reference a global defined by 'llvm.mlir.global', "
-                       "'llvm.mlir.alias' or 'llvm.func'");
+                       "'llvm.mlir.alias' or 'llvm.func' or 'llvm.mlir.ifunc'");
 
   LLVMPointerType type = getType();
   if ((global && global.getAddrSpace() != type.getAddressSpace()) ||
@@ -2682,6 +2694,56 @@ unsigned AliasOp::getAddrSpace() {
   return ptrTy.getAddressSpace();
 }
 
+//===----------------------------------------------------------------------===//
+// IFuncOp
+//===----------------------------------------------------------------------===//
+
+void IFuncOp::build(OpBuilder &builder, OperationState &result, StringRef name,
+                    Type iFuncType, StringRef resolverName, Type resolverType,
+                    Linkage linkage, LLVM::Visibility visibility) {
+  return build(builder, result, name, iFuncType, resolverName, resolverType,
+               /* dso_local */ false, /* addr_space */ 0, linkage,
+               UnnamedAddr::None, visibility);
+}
+LogicalResult IFuncOp::verifySymbolUses(SymbolTableCollection &symbolTable) {
+  return success();
+  Operation *symbol =
+      symbolTable.lookupSymbolIn(parentLLVMModule(*this), getResolverAttr());
+  auto resolver = dyn_cast<LLVMFuncOp>(symbol);
+  if (!resolver)
+    return emitOpError("IFunc must have a Function resolver");
+
+  // Copying logic from llvm/lib/IR/Verifier.cpp
+  Linkage linkage = resolver.getLinkage();
+  if (resolver.isExternal() || linkage == Linkage::AvailableExternally)
+    return emitOpError("IFunc resolver must be a definition");
+  if (!isa<LLVMPointerType>(resolver.getFunctionType().getReturnType()))
+    return emitOpError("IFunc resolver must return a pointer");
+  auto resolverPtr = dyn_cast<LLVMPointerType>(getResolverType());
+  if (!resolverPtr || resolverPtr.getAddressSpace() != getAddressSpace())
+    return emitOpError("IFunc resolver has incorrect type");
+  return success();
+}
+
+LogicalResult IFuncOp::verify() {
+  switch (getLinkage()) {
+  case Linkage::External:
+  case Linkage::Internal:
+  case Linkage::Private:
+  case Linkage::Weak:
+  case Linkage::WeakODR:
+  case Linkage::Linkonce:
+  case Linkage::LinkonceODR:
+    break;
+  default:
+    return emitOpError() << "'" << stringifyLinkage(getLinkage())
+                         << "' linkage not supported in ifuncs, available "
+                            "options: private, internal, linkonce, weak, "
+                            "linkonce_odr, weak_odr, or external linkage";
+  }
+  return success();
+}
+
 //===----------------------------------------------------------------------===//
 // ShuffleVectorOp
 //===----------------------------------------------------------------------===//
@@ -4329,3 +4391,11 @@ bool mlir::LLVM::satisfiesLLVMModule(Operation *op) {
   return op->hasTrait<OpTrait::SymbolTable>() &&
          op->hasTrait<OpTrait::IsIsolatedFromAbove>();
 }
+
+Operation *mlir::LLVM::parentLLVMModule(Operation *op) {
+  Operation *module = op->getParentOp();
+  while (module && !satisfiesLLVMModule(module))
+    module = module->getParentOp();
+  assert(module && "unexpected operation outside of a module");
+  return module;
+}
diff --git a/mlir/lib/Target/LLVMIR/Dialect/LLVMIR/LLVMToLLVMIRTranslation.cpp b/mlir/lib/Target/LLVMIR/Dialect/LLVMIR/LLVMToLLVMIRTranslation.cpp
index 70029d7e15a90..9a648ecd3a8d2 100644
--- a/mlir/lib/Target/LLVMIR/Dialect/LLVMIR/LLVMToLLVMIRTranslation.cpp
+++ b/mlir/lib/Target/LLVMIR/Dialect/LLVMIR/LLVMToLLVMIRTranslation.cpp
@@ -422,9 +422,18 @@ convertOperationImpl(Operation &opInst, llvm::IRBuilderBase &builder,
     ArrayRef<llvm::Value *> operandsRef(operands);
     llvm::CallInst *call;
     if (auto attr = callOp.getCalleeAttr()) {
-      call =
-          builder.CreateCall(moduleTranslation.lookupFunction(attr.getValue()),
-                             operandsRef, opBundles);
+      if (llvm::Function *function =
+              moduleTranslation.lookupFunction(attr.getValue())) {
+        call = builder.CreateCall(function, operandsRef, opBundles);
+      } else {
+        Operation *module = parentLLVMModule(&opInst);
+        Operation *ifuncOp =
+            moduleTranslation.symbolTable().lookupSymbolIn(module, attr);
+        llvm::GlobalValue *ifunc = moduleTranslation.lookupIFunc(ifuncOp);
+        llvm::FunctionType *calleeType = llvm::cast<llvm::FunctionType>(
+            moduleTranslation.convertType(callOp.getCalleeFunctionType()));
+        call = builder.CreateCall(calleeType, ifunc, operandsRef, opBundles);
+      }
     } else {
       llvm::FunctionType *calleeType = llvm::cast<llvm::FunctionType>(
           moduleTranslation.convertType(callOp.getCalleeFunctionType()));
@@ -648,18 +657,21 @@ convertOperationImpl(Operation &opInst, llvm::IRBuilderBase &builder,
     LLVM::LLVMFuncOp function =
         addressOfOp.getFunction(moduleTranslation.symbolTable());
     LLVM::AliasOp alias = addressOfOp.getAlias(moduleTranslation.symbolTable());
+    LLVM::IFuncOp ifunc = addressOfOp.getIFunc(moduleTranslation.symbolTable());
 
     // The verifier should not have allowed this.
-    assert((global || function || alias) &&
-           "referencing an undefined global, function, or alias");
+    assert((global || function || alias || ifunc) &&
+           "referencing an undefined global, function, alias, or ifunc");
 
     llvm::Value *llvmValue = nullptr;
     if (global)
       llvmValue = moduleTranslation.lookupGlobal(global);
     else if (alias)
       llvmValue = moduleTranslation.lookupAlias(alias);
-    else
+    else if (function)
       llvmValue = moduleTranslation.lookupFunction(function.getName());
+    else
+      llvmValue = moduleTranslation.lookupIFunc(ifunc);
 
     moduleTranslation.mapValue(addressOfOp.getResult(), llvmValue);
     return success();
diff --git a/mlir/lib/Target/LLVMIR/ModuleImport.cpp b/mlir/lib/Target/LLVMIR/ModuleImport.cpp
index bfda223fe0f5f..a88e1c9847fcf 100644
--- a/mlir/lib/Target/LLVMIR/ModuleImport.cpp
+++ b/mlir/lib/Target/LLVMIR/ModuleImport.cpp
@@ -1031,6 +1031,16 @@ LogicalResult ModuleImport::convertAliases() {
   return success();
 }
 
+LogicalResult ModuleImport::convertIFuncs() {
+  for (llvm::GlobalIFunc &ifunc : llvmModule->ifuncs()) {
+    if (failed(convertIFunc(&ifunc))) {
+      return emitError(UnknownLoc::get(context))
+             << "unhandled global ifunc: " << diag(ifunc);
+    }
+  }
+  return success();
+}
+
 LogicalResult ModuleImport::convertDataLayout() {
   Location loc = mlirModule.getLoc();
   DataLayoutImporter dataLayoutImporter(context, llvmModule->getDataLayout());
@@ -1369,6 +1379,21 @@ LogicalResult ModuleImport::convertAlias(llvm::GlobalAlias *alias) {
   return success();
 }
 
+LogicalResult ModuleImport::convertIFunc(llvm::GlobalIFunc *ifunc) {
+  OpBuilder::InsertionGuard guard = setGlobalInsertionPoint();
+
+  Type type = convertType(ifunc->getValueType());
+  llvm::Constant *resolver = ifunc->getResolver();
+  Type resolverType = convertType(resolver->getType());
+  builder.create<IFuncOp>(mlirModule.getLoc(), ifunc->getName(), type,
+                          resolver->getName(), resolverType,
+                          ifunc->isDSOLocal(), ifunc->getAddressSpace(),
+                          convertLinkageFromLLVM(ifunc->getLinkage()),
+                          convertUnnamedAddrFromLLVM(ifunc->getUnnamedAddr()),
+                          convertVisibilityFromLLVM(ifunc->getVisibility()));
+  return success();
+}
+
 LogicalResult ModuleImport::convertGlobal(llvm::GlobalVariable *globalVar) {
   // Insert the global after the last one or at the start of the module.
   OpBuilder::InsertionGuard guard = setGlobalInsertionPoint();
@@ -1973,8 +1998,9 @@ ModuleImport::convertCallOperands(llvm::CallBase *callInst,
   // treated as indirect calls to constant operands that need to be converted.
   // Skip the callee operand if it's inline assembly, as it's handled separately
   // in InlineAsmOp.
-  if (!isa<llvm::Function>(callInst->getCalledOperand()) && !isInlineAsm) {
-    FailureOr<Value> called = convertValue(callInst->getCalledOperand());
+  llvm::Value *caleeOperand = callInst->getCalledOperand();
+  if (!isa<llvm::Function, llvm::GlobalIFunc>(caleeOperand) && !isInlineAsm) {
+    FailureOr<Value> called = convertValue(caleeOperand);
     if (failed(called))
       return failure();
     operands.push_back(*called);
@@ -2035,12 +2061,21 @@ ModuleImport::convertFunctionType(llvm::CallBase *callInst,
   if (failed(callType))
     return failure();
   auto *callee = dyn_cast<llvm::Function>(calledOperand);
+
+  llvm::FunctionType *origCalleeType = nullptr;
+  if (callee) {
+    origCalleeType = callee->getFunctionType();
+  } else if (auto *ifunc = dyn_cast<llvm::GlobalIFunc>(calledOperand)) {
+    origCalleeType =
+        dyn_cast_or_null<llvm::FunctionType>(ifunc->getValueType());
+  }
+
   // For indirect calls, return the type of the call itself.
-  if (!callee)
+  if (!origCalleeType)
     return callType;
 
   FailureOr<LLVMFunctionType> calleeType =
-      castOrFailure(convertType(callee->getFunctionType()));
+      castOrFailure(convertType(origCalleeType));
   if (failed(calleeType))
     return failure();
 
@@ -2059,8 +2094,8 @@ ModuleImport::convertFunctionType(llvm::CallBase *callInst,
 
 FlatSymbolRefAttr ModuleImport::convertCalleeName(llvm::CallBase *callInst) {
   llvm::Value *calledOperand = callInst->getCalledOperand();
-  if (auto *callee = dyn_cast<llvm::Function>(calledOperand))
-    return SymbolRefAttr::get(context, callee->getName());
+  if (isa<llvm::Function, llvm::GlobalIFunc>(calledOperand))
+    return SymbolRefAttr::get(context, calledOperand->getName());
   return {};
 }
 
@@ -3162,6 +3197,8 @@ OwningOpRef<ModuleOp> mlir::translateLLVMIRToModule(
     return {};
   if (failed(moduleImport.convertAliases()))
     return {};
+  if (failed(moduleImport.convertIFuncs()))
+    return {};
   moduleImport.convertTargetTriple();
   return module;
 }
diff --git a/mlir/lib/Target/LLVMIR/ModuleTranslation.cpp b/mlir/lib/Target/LLVMIR/ModuleTranslation.cpp
index 8908703cc1368..1a2a585e34d44 100644
--- a/mlir/lib/Target/LLVMIR/ModuleTranslation.cpp
+++ b/mlir/lib/Target/LLVMIR/ModuleTranslation.cpp
@@ -791,6 +791,8 @@ void ModuleTranslation::forgetMapping(Region &region) {
           globalsMapping.erase(&op);
         if (isa<LLVM::AliasOp>(op))
           aliasesMapping.erase(&op);
+        if (isa<LLVM::IFuncOp>(op))
+          ifuncMapping.erase(&op);
         if (isa<LLVM::CallOp>(op))
           callMapping.erase(&op);
         llvm::append_range(
@@ -1868,6 +1870,27 @@ LogicalResult ModuleTranslation::convertFunctions() {
   return success();
 }
 
+LogicalResult ModuleTranslation::convertIFuncs() {
+  for (auto op : getModuleBody(mlirModule).getOps<IFuncOp>()) {
+    llvm::Type *type = convertType(op.getIFuncType());
+    llvm::GlobalValue::LinkageTypes linkage =
+        convertLinkageToLLVM(op.getLinkage());
+    llvm::Constant *cst =
+        dyn_cast<llvm::Constant>(lookupFunction(op.getResolver()));
+
+    auto *ifunc =
+        llvm::GlobalIFunc::create(type, op.getAddressSpace(), linkage,
+                                  op.getSymName(), cst, llvmMod...
[truncated]

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Nice! Thanks for adding ifuncs.

The direction looks good module some nits. The tests need a bit more work though. The current ones are a bit long and could probably be simplified? Additionally, adding some tests for the verifiers (invalid.mlir) and possibly some roundtrip tests for the custom printing and parsing would make sense.

Type iFuncType, StringRef resolverName, Type resolverType,
Linkage linkage, LLVM::Visibility visibility) {
return build(builder, result, name, iFuncType, resolverName, resolverType,
/* dso_local */ false, /* addr_space */ 0, linkage,
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Suggested change
/* dso_local */ false, /* addr_space */ 0, linkage,
/*dso_local=*/false, /*addr_space=*/0, linkage,

nit: style

UnnamedAddr::None, visibility);
}
LogicalResult IFuncOp::verifySymbolUses(SymbolTableCollection &symbolTable) {
return success();
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That makes me believe the PR needs some more verifier tests!

Comment on lines +2707 to +2708
}
LogicalResult IFuncOp::verifySymbolUses(SymbolTableCollection &symbolTable) {
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Suggested change
}
LogicalResult IFuncOp::verifySymbolUses(SymbolTableCollection &symbolTable) {
}
LogicalResult IFuncOp::verifySymbolUses(SymbolTableCollection &symbolTable) {

nit missing newline

llvm::Type *type = convertType(op.getIFuncType());
llvm::GlobalValue::LinkageTypes linkage =
convertLinkageToLLVM(op.getLinkage());
llvm::Constant *cst =
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Suggested change
llvm::Constant *cst =
llvm::Constant *resolver =

nit: I would probably go with resolver or similar to be more specific.

moduleTranslation.lookupFunction(attr.getValue())) {
call = builder.CreateCall(function, operandsRef, opBundles);
} else {
Operation *module = parentLLVMModule(&opInst);
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Suggested change
Operation *module = parentLLVMModule(&opInst);
Operation *moduleOp = parentLLVMModule(&opInst);

nit: Let's use module op to avoid the red color.

I wonder if it would make sense if LLVM::CallOp would have a getFunction / getIFunc helper similar to the addressOf operation. But I suspect this would likely be the only use here?

if (!resolver)
return emitOpError("IFunc must have a Function resolver");

// Copying logic from llvm/lib/IR/Verifier.cpp
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// Copying logic from llvm/lib/IR/Verifier.cpp
// This matches LLVM IR verification logic, see from llvm/lib/IR/Verifier.cpp

ultra nit: I suggest to avoid the term copying since it reminds of copy pasta :)

@@ -1973,8 +1998,9 @@ ModuleImport::convertCallOperands(llvm::CallBase *callInst,
// treated as indirect calls to constant operands that need to be converted.
// Skip the callee operand if it's inline assembly, as it's handled separately
// in InlineAsmOp.
if (!isa<llvm::Function>(callInst->getCalledOperand()) && !isInlineAsm) {
FailureOr<Value> called = convertValue(callInst->getCalledOperand());
llvm::Value *caleeOperand = callInst->getCalledOperand();
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llvm::Value *caleeOperand = callInst->getCalledOperand();
llvm::Value *calleeOperand = callInst->getCalledOperand();

origCalleeType = callee->getFunctionType();
} else if (auto *ifunc = dyn_cast<llvm::GlobalIFunc>(calledOperand)) {
origCalleeType =
dyn_cast_or_null<llvm::FunctionType>(ifunc->getValueType());
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Shouldn't getValueType always return a function type? Could we use cast here? Or dyn_cast?

@@ -0,0 +1,115 @@
; RUN: mlir-translate --import-llvm %s -split-input-file | FileCheck %s

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The tests are quite long compared to what we actually check. Is it possible to significantly simplify them by dropping code that is actually not needed e.g. most of the function bodies?

Also can we check some more attributes such as linkage etc. Maybe use a minimal ifunc in some case and add all the optional attributes on a second ifunc?

@@ -0,0 +1,123 @@
// RUN: mlir-translate -mlir-to-llvmir %s -split-input-file | FileCheck %s

llvm.mlir.global private unnamed_addr constant @__const.main.data(dense<[1, 2, 3, 4, 5, 6, 7, 8, 9, 10]> : tensor<10xi32>) {addr_space = 0 : i32, alignment = 16 : i64, dso_local} : !llvm.array<10 x i32>
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Can you shorten this test as well as proposed for the import test?

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3 participants