[MLIR] Make OneShotModuleBufferize use OpInterface (#107295)

**Description:** 

`OneShotModuleBufferize` deals with the bufferization of `FuncOp`,
`CallOp` and `ReturnOp` but they are hard-coded. Any custom
function-like operations will not be handled. The PR replaces a part of
`FuncOp` and `CallOp` with `FunctionOpInterface` and `CallOpInterface`
in `OneShotModuleBufferize` so that custom function ops and call ops can
be bufferized.

**Related Discord Discussion:**
[Link](https://discord.com/channels/636084430946959380/642426447167881246/1280556809911799900)

---------

Co-authored-by: erick-xanadu <[email protected]>

Author: Tzung-Han Juang

mlir/include/mlir/Dialect/Bufferization/IR/BufferizableOpInterface.h

@@ -11,6 +11,7 @@
 
 #include "mlir/IR/Operation.h"
 #include "mlir/IR/PatternMatch.h"
+#include "mlir/Interfaces/FunctionInterfaces.h"
 #include "mlir/Support/LLVM.h"
 #include "llvm/ADT/DenseMapInfoVariant.h"
 #include "llvm/ADT/SetVector.h"
@@ -260,9 +261,9 @@ struct BufferizationOptions {
   using AnalysisStateInitFn = std::function<void(AnalysisState &)>;
   /// Tensor -> MemRef type converter.
   /// Parameters: Value, memory space, func op, bufferization options
-  using FunctionArgTypeConverterFn =
-      std::function<BaseMemRefType(TensorType, Attribute memorySpace,
-                                   func::FuncOp, const BufferizationOptions &)>;
+  using FunctionArgTypeConverterFn = std::function<BaseMemRefType(
+      TensorType, Attribute memorySpace, FunctionOpInterface,
+      const BufferizationOptions &)>;
   /// Tensor -> MemRef type converter.
   /// Parameters: Value, memory space, bufferization options
   using UnknownTypeConverterFn = std::function<BaseMemRefType(

mlir/include/mlir/Dialect/Bufferization/Transforms/FuncBufferizableOpInterfaceImpl.h

@@ -50,24 +50,24 @@ struct FuncAnalysisState : public OneShotAnalysisState::Extension {
 
   /// A mapping of ReturnOp OpOperand indices to equivalent FuncOp BBArg
   /// indices.
-  DenseMap<FuncOp, IndexMapping> equivalentFuncArgs;
+  DenseMap<FunctionOpInterface, IndexMapping> equivalentFuncArgs;
 
   /// A mapping of FuncOp BBArg indices to aliasing ReturnOp OpOperand indices.
-  DenseMap<FuncOp, IndexToIndexListMapping> aliasingReturnVals;
+  DenseMap<FunctionOpInterface, IndexToIndexListMapping> aliasingReturnVals;
 
   /// A set of all read BlockArguments of FuncOps.
-  DenseMap<FuncOp, BbArgIndexSet> readBbArgs;
+  DenseMap<FunctionOpInterface, BbArgIndexSet> readBbArgs;
 
   /// A set of all written-to BlockArguments of FuncOps.
-  DenseMap<FuncOp, BbArgIndexSet> writtenBbArgs;
+  DenseMap<FunctionOpInterface, BbArgIndexSet> writtenBbArgs;
 
   /// Keep track of which FuncOps are fully analyzed or currently being
   /// analyzed.
-  DenseMap<FuncOp, FuncOpAnalysisState> analyzedFuncOps;
+  DenseMap<FunctionOpInterface, FuncOpAnalysisState> analyzedFuncOps;
 
   /// This function is called right before analyzing the given FuncOp. It
   /// initializes the data structures for the FuncOp in this state object.
-  void startFunctionAnalysis(FuncOp funcOp);
+  void startFunctionAnalysis(FunctionOpInterface funcOp);
 };
 
 void registerBufferizableOpInterfaceExternalModels(DialectRegistry &registry);

mlir/lib/Dialect/Bufferization/IR/BufferizableOpInterface.cpp

@@ -18,6 +18,7 @@
 #include "mlir/IR/TypeUtilities.h"
 #include "mlir/IR/Value.h"
 #include "mlir/Interfaces/ControlFlowInterfaces.h"
+#include "mlir/Interfaces/FunctionInterfaces.h"
 #include "llvm/ADT/ScopeExit.h"
 #include "llvm/Support/Debug.h"
 
@@ -314,7 +315,7 @@ namespace {
 /// Default function arg type converter: Use a fully dynamic layout map.
 BaseMemRefType
 defaultFunctionArgTypeConverter(TensorType type, Attribute memorySpace,
-                                func::FuncOp funcOp,
+                                FunctionOpInterface funcOp,
                                 const BufferizationOptions &options) {
   return getMemRefTypeWithFullyDynamicLayout(type, memorySpace);
 }
@@ -361,7 +362,7 @@ BufferizationOptions::dynCastBufferizableOp(Value value) const {
 void BufferizationOptions::setFunctionBoundaryTypeConversion(
     LayoutMapOption layoutMapOption) {
   functionArgTypeConverterFn = [=](TensorType tensorType, Attribute memorySpace,
-                                   func::FuncOp funcOp,
+                                   FunctionOpInterface funcOp,
                                    const BufferizationOptions &options) {
     if (layoutMapOption == LayoutMapOption::IdentityLayoutMap)
       return bufferization::getMemRefTypeWithStaticIdentityLayout(tensorType,

mlir/lib/Dialect/Bufferization/Transforms/FuncBufferizableOpInterfaceImpl.cpp

@@ -22,7 +22,7 @@ namespace mlir {
 namespace bufferization {
 namespace func_ext {
 
-void FuncAnalysisState::startFunctionAnalysis(FuncOp funcOp) {
+void FuncAnalysisState::startFunctionAnalysis(FunctionOpInterface funcOp) {
   analyzedFuncOps[funcOp] = FuncOpAnalysisState::InProgress;
   auto createdEquiv = equivalentFuncArgs.try_emplace(funcOp, IndexMapping());
   auto createdAliasingResults =

mlir/lib/Dialect/Bufferization/Transforms/OneShotModuleBufferize.cpp

@@ -75,7 +75,7 @@ using namespace mlir::bufferization;
 using namespace mlir::bufferization::func_ext;
 
 /// A mapping of FuncOps to their callers.
-using FuncCallerMap = DenseMap<func::FuncOp, DenseSet<Operation *>>;
+using FuncCallerMap = DenseMap<FunctionOpInterface, DenseSet<Operation *>>;
 
 /// Get or create FuncAnalysisState.
 static FuncAnalysisState &
@@ -88,10 +88,11 @@ getOrCreateFuncAnalysisState(OneShotAnalysisState &state) {
 
 /// Return the unique ReturnOp that terminates `funcOp`.
 /// Return nullptr if there is no such unique ReturnOp.
-static func::ReturnOp getAssumedUniqueReturnOp(func::FuncOp funcOp) {
-  func::ReturnOp returnOp;
-  for (Block &b : funcOp.getBody()) {
-    if (auto candidateOp = dyn_cast<func::ReturnOp>(b.getTerminator())) {
+static Operation *getAssumedUniqueReturnOp(FunctionOpInterface funcOp) {
+  Operation *returnOp = nullptr;
+  for (Block &b : funcOp.getFunctionBody()) {
+    auto candidateOp = b.getTerminator();
+    if (candidateOp && candidateOp->hasTrait<OpTrait::ReturnLike>()) {
       if (returnOp)
         return nullptr;
       returnOp = candidateOp;
@@ -126,16 +127,16 @@ static void annotateEquivalentReturnBbArg(OpOperand &returnVal,
 /// Store function BlockArguments that are equivalent to/aliasing a returned
 /// value in FuncAnalysisState.
 static LogicalResult
-aliasingFuncOpBBArgsAnalysis(FuncOp funcOp, OneShotAnalysisState &state,
+aliasingFuncOpBBArgsAnalysis(FunctionOpInterface funcOp,
+                             OneShotAnalysisState &state,
                              FuncAnalysisState &funcState) {
-  if (funcOp.getBody().empty()) {
+  if (funcOp.getFunctionBody().empty()) {
     // No function body available. Conservatively assume that every tensor
     // return value may alias with any tensor bbArg.
-    FunctionType type = funcOp.getFunctionType();
-    for (const auto &inputIt : llvm::enumerate(type.getInputs())) {
+    for (const auto &inputIt : llvm::enumerate(funcOp.getArgumentTypes())) {
       if (!isa<TensorType>(inputIt.value()))
         continue;
-      for (const auto &resultIt : llvm::enumerate(type.getResults())) {
+      for (const auto &resultIt : llvm::enumerate(funcOp.getResultTypes())) {
         if (!isa<TensorType>(resultIt.value()))
           continue;
         int64_t returnIdx = resultIt.index();
@@ -147,7 +148,7 @@ aliasingFuncOpBBArgsAnalysis(FuncOp funcOp, OneShotAnalysisState &state,
   }
 
   // Support only single return-terminated block in the function.
-  func::ReturnOp returnOp = getAssumedUniqueReturnOp(funcOp);
+  Operation *returnOp = getAssumedUniqueReturnOp(funcOp);
   assert(returnOp && "expected func with single return op");
 
   for (OpOperand &returnVal : returnOp->getOpOperands())
@@ -168,8 +169,8 @@ aliasingFuncOpBBArgsAnalysis(FuncOp funcOp, OneShotAnalysisState &state,
   return success();
 }
 
-static void annotateFuncArgAccess(func::FuncOp funcOp, int64_t idx, bool isRead,
-                                  bool isWritten) {
+static void annotateFuncArgAccess(FunctionOpInterface funcOp, int64_t idx,
+                                  bool isRead, bool isWritten) {
   OpBuilder b(funcOp.getContext());
   Attribute accessType;
   if (isRead && isWritten) {
@@ -189,12 +190,12 @@ static void annotateFuncArgAccess(func::FuncOp funcOp, int64_t idx, bool isRead,
 /// function with unknown ops, we conservatively assume that such ops bufferize
 /// to a read + write.
 static LogicalResult
-funcOpBbArgReadWriteAnalysis(FuncOp funcOp, OneShotAnalysisState &state,
+funcOpBbArgReadWriteAnalysis(FunctionOpInterface funcOp,
+                             OneShotAnalysisState &state,
                              FuncAnalysisState &funcState) {
-  for (int64_t idx = 0, e = funcOp.getFunctionType().getNumInputs(); idx < e;
-       ++idx) {
+  for (int64_t idx = 0, e = funcOp.getNumArguments(); idx < e; ++idx) {
     // Skip non-tensor arguments.
-    if (!isa<TensorType>(funcOp.getFunctionType().getInput(idx)))
+    if (!isa<TensorType>(funcOp.getArgumentTypes()[idx]))
       continue;
     bool isRead;
     bool isWritten;
@@ -204,7 +205,7 @@ funcOpBbArgReadWriteAnalysis(FuncOp funcOp, OneShotAnalysisState &state,
       StringRef str = accessAttr.getValue();
       isRead = str == "read" || str == "read-write";
       isWritten = str == "write" || str == "read-write";
-    } else if (funcOp.getBody().empty()) {
+    } else if (funcOp.getFunctionBody().empty()) {
       // If the function has no body, conservatively assume that all args are
       // read + written.
       isRead = true;
@@ -230,33 +231,32 @@ funcOpBbArgReadWriteAnalysis(FuncOp funcOp, OneShotAnalysisState &state,
 
 /// Remove bufferization attributes on FuncOp arguments.
 static void removeBufferizationAttributes(BlockArgument bbArg) {
-  auto funcOp = cast<func::FuncOp>(bbArg.getOwner()->getParentOp());
+  auto funcOp = cast<FunctionOpInterface>(bbArg.getOwner()->getParentOp());
   funcOp.removeArgAttr(bbArg.getArgNumber(),
                        BufferizationDialect::kBufferLayoutAttrName);
   funcOp.removeArgAttr(bbArg.getArgNumber(),
                        BufferizationDialect::kWritableAttrName);
 }
 
-/// Return the func::FuncOp called by `callOp`.
-static func::FuncOp getCalledFunction(func::CallOp callOp) {
+static FunctionOpInterface getCalledFunction(CallOpInterface callOp) {
   SymbolRefAttr sym =
       llvm::dyn_cast_if_present<SymbolRefAttr>(callOp.getCallableForCallee());
   if (!sym)
     return nullptr;
-  return dyn_cast_or_null<func::FuncOp>(
+  return dyn_cast_or_null<FunctionOpInterface>(
       SymbolTable::lookupNearestSymbolFrom(callOp, sym));
 }
 
 /// Gather equivalence info of CallOps.
 /// Note: This only adds new equivalence info if the called function was already
 /// analyzed.
 // TODO: This does not handle cyclic function call graphs etc.
-static void equivalenceAnalysis(func::FuncOp funcOp,
+static void equivalenceAnalysis(FunctionOpInterface funcOp,
                                 OneShotAnalysisState &state,
                                 FuncAnalysisState &funcState) {
-  funcOp->walk([&](func::CallOp callOp) {
-    func::FuncOp calledFunction = getCalledFunction(callOp);
-    assert(calledFunction && "could not retrieved called func::FuncOp");
+  funcOp->walk([&](CallOpInterface callOp) {
+    FunctionOpInterface calledFunction = getCalledFunction(callOp);
+    assert(calledFunction && "could not retrieved called FunctionOpInterface");
 
     // No equivalence info available for the called function.
     if (!funcState.equivalentFuncArgs.count(calledFunction))
@@ -267,7 +267,7 @@ static void equivalenceAnalysis(func::FuncOp funcOp,
       int64_t bbargIdx = it.second;
       if (!state.isInPlace(callOp->getOpOperand(bbargIdx)))
         continue;
-      Value returnVal = callOp.getResult(returnIdx);
+      Value returnVal = callOp->getResult(returnIdx);
       Value argVal = callOp->getOperand(bbargIdx);
       state.unionEquivalenceClasses(returnVal, argVal);
     }
@@ -277,11 +277,9 @@ static void equivalenceAnalysis(func::FuncOp funcOp,
 }
 
 /// Return "true" if the given function signature has tensor semantics.
-static bool hasTensorSignature(func::FuncOp funcOp) {
-  return llvm::any_of(funcOp.getFunctionType().getInputs(),
-                      llvm::IsaPred<TensorType>) ||
-         llvm::any_of(funcOp.getFunctionType().getResults(),
-                      llvm::IsaPred<TensorType>);
+static bool hasTensorSignature(FunctionOpInterface funcOp) {
+  return llvm::any_of(funcOp.getArgumentTypes(), llvm::IsaPred<TensorType>) ||
+         llvm::any_of(funcOp.getResultTypes(), llvm::IsaPred<TensorType>);
 }
 
 /// Store all functions of the `moduleOp` in `orderedFuncOps`, sorted by
@@ -291,16 +289,16 @@ static bool hasTensorSignature(func::FuncOp funcOp) {
 /// retrieve the called FuncOp from any func::CallOp.
 static LogicalResult
 getFuncOpsOrderedByCalls(ModuleOp moduleOp,
-                         SmallVectorImpl<func::FuncOp> &orderedFuncOps,
+                         SmallVectorImpl<FunctionOpInterface> &orderedFuncOps,
                          FuncCallerMap &callerMap) {
   // For each FuncOp, the set of functions called by it (i.e. the union of
   // symbols of all nested func::CallOp).
-  DenseMap<func::FuncOp, DenseSet<func::FuncOp>> calledBy;
+  DenseMap<FunctionOpInterface, DenseSet<FunctionOpInterface>> calledBy;
   // For each FuncOp, the number of func::CallOp it contains.
-  DenseMap<func::FuncOp, unsigned> numberCallOpsContainedInFuncOp;
-  WalkResult res = moduleOp.walk([&](func::FuncOp funcOp) -> WalkResult {
-    if (!funcOp.getBody().empty()) {
-      func::ReturnOp returnOp = getAssumedUniqueReturnOp(funcOp);
+  DenseMap<FunctionOpInterface, unsigned> numberCallOpsContainedInFuncOp;
+  WalkResult res = moduleOp.walk([&](FunctionOpInterface funcOp) -> WalkResult {
+    if (!funcOp.getFunctionBody().empty()) {
+      Operation *returnOp = getAssumedUniqueReturnOp(funcOp);
       if (!returnOp)
         return funcOp->emitError()
                << "cannot bufferize a FuncOp with tensors and "
@@ -309,9 +307,10 @@ getFuncOpsOrderedByCalls(ModuleOp moduleOp,
 
     // Collect function calls and populate the caller map.
     numberCallOpsContainedInFuncOp[funcOp] = 0;
-    return funcOp.walk([&](func::CallOp callOp) -> WalkResult {
-      func::FuncOp calledFunction = getCalledFunction(callOp);
-      assert(calledFunction && "could not retrieved called func::FuncOp");
+    return funcOp.walk([&](CallOpInterface callOp) -> WalkResult {
+      FunctionOpInterface calledFunction = getCalledFunction(callOp);
+      assert(calledFunction &&
+             "could not retrieved called FunctionOpInterface");
       // If the called function does not have any tensors in its signature, then
       // it is not necessary to bufferize the callee before the caller.
       if (!hasTensorSignature(calledFunction))
@@ -349,11 +348,11 @@ getFuncOpsOrderedByCalls(ModuleOp moduleOp,
 /// most generic layout map as function return types. After bufferizing the
 /// entire function body, a more concise memref type can potentially be used for
 /// the return type of the function.
-static void foldMemRefCasts(func::FuncOp funcOp) {
-  if (funcOp.getBody().empty())
+static void foldMemRefCasts(FunctionOpInterface funcOp) {
+  if (funcOp.getFunctionBody().empty())
     return;
 
-  func::ReturnOp returnOp = getAssumedUniqueReturnOp(funcOp);
+  Operation *returnOp = getAssumedUniqueReturnOp(funcOp);
   SmallVector<Type> resultTypes;
 
   for (OpOperand &operand : returnOp->getOpOperands()) {
@@ -365,8 +364,8 @@ static void foldMemRefCasts(func::FuncOp funcOp) {
     }
   }
 
-  auto newFuncType = FunctionType::get(
-      funcOp.getContext(), funcOp.getFunctionType().getInputs(), resultTypes);
+  auto newFuncType = FunctionType::get(funcOp.getContext(),
+                                       funcOp.getArgumentTypes(), resultTypes);
   funcOp.setType(newFuncType);
 }
 
@@ -379,7 +378,7 @@ mlir::bufferization::analyzeModuleOp(ModuleOp moduleOp,
   FuncAnalysisState &funcState = getOrCreateFuncAnalysisState(state);
 
   // A list of functions in the order in which they are analyzed + bufferized.
-  SmallVector<func::FuncOp> orderedFuncOps;
+  SmallVector<FunctionOpInterface> orderedFuncOps;
 
   // A mapping of FuncOps to their callers.
   FuncCallerMap callerMap;
@@ -388,7 +387,7 @@ mlir::bufferization::analyzeModuleOp(ModuleOp moduleOp,
     return failure();
 
   // Analyze ops.
-  for (func::FuncOp funcOp : orderedFuncOps) {
+  for (FunctionOpInterface funcOp : orderedFuncOps) {
     if (!state.getOptions().isOpAllowed(funcOp))
       continue;
 
@@ -416,7 +415,7 @@ mlir::bufferization::analyzeModuleOp(ModuleOp moduleOp,
 
 void mlir::bufferization::removeBufferizationAttributesInModule(
     ModuleOp moduleOp) {
-  moduleOp.walk([&](func::FuncOp op) {
+  moduleOp.walk([&](FunctionOpInterface op) {
     for (BlockArgument bbArg : op.getArguments())
       removeBufferizationAttributes(bbArg);
   });
@@ -430,7 +429,7 @@ LogicalResult mlir::bufferization::bufferizeModuleOp(
   IRRewriter rewriter(moduleOp.getContext());
 
   // A list of functions in the order in which they are analyzed + bufferized.
-  SmallVector<func::FuncOp> orderedFuncOps;
+  SmallVector<FunctionOpInterface> orderedFuncOps;
 
   // A mapping of FuncOps to their callers.
   FuncCallerMap callerMap;
@@ -439,11 +438,11 @@ LogicalResult mlir::bufferization::bufferizeModuleOp(
     return failure();
 
   // Bufferize functions.
-  for (func::FuncOp funcOp : orderedFuncOps) {
+  for (FunctionOpInterface funcOp : orderedFuncOps) {
     // Note: It would be good to apply cleanups here but we cannot as aliasInfo
     // would be invalidated.
 
-    if (llvm::is_contained(options.noAnalysisFuncFilter, funcOp.getSymName())) {
+    if (llvm::is_contained(options.noAnalysisFuncFilter, funcOp.getName())) {
       // This function was not analyzed and RaW conflicts were not resolved.
       // Buffer copies must be inserted before every write.
       OneShotBufferizationOptions updatedOptions = options;
@@ -463,7 +462,7 @@ LogicalResult mlir::bufferization::bufferizeModuleOp(
   // Bufferize all other ops.
   for (Operation &op : llvm::make_early_inc_range(moduleOp.getOps())) {
     // Functions were already bufferized.
-    if (isa<func::FuncOp>(&op))
+    if (isa<FunctionOpInterface>(&op))
       continue;
     if (failed(bufferizeOp(&op, options, statistics)))
       return failure();
@@ -490,12 +489,12 @@ LogicalResult mlir::bufferization::runOneShotModuleBufferize(
       // FuncOps whose names are specified in options.noAnalysisFuncFilter will
       // not be analyzed. Ops in these FuncOps will not be analyzed as well.
       OpFilter::Entry::FilterFn analysisFilterFn = [=](Operation *op) {
-        auto func = dyn_cast<func::FuncOp>(op);
+        auto func = dyn_cast<FunctionOpInterface>(op);
         if (!func)
-          func = op->getParentOfType<func::FuncOp>();
+          func = op->getParentOfType<FunctionOpInterface>();
         if (func)
           return llvm::is_contained(options.noAnalysisFuncFilter,
-                                    func.getSymName());
+                                    func.getName());
         return false;
       };
       OneShotBufferizationOptions updatedOptions(options);