[flang-commits] [flang] [flang] Introduce omp_target_allocmem and omp_target_freemem fir ops. (PR #145464)
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Mon Jun 23 23:07:01 PDT 2025
https://github.com/skc7 created https://github.com/llvm/llvm-project/pull/145464
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>From 4915fb8f1d27847dc3d36899e233d5ac988f96c5 Mon Sep 17 00:00:00 2001
From: skc7 <Krishna.Sankisa at amd.com>
Date: Mon, 23 Jun 2025 16:39:55 +0530
Subject: [PATCH] [flang] Introduce omp_target_allocmem and omp_target_freemem
fir ops.
---
.../include/flang/Optimizer/Dialect/FIROps.td | 58 ++++++++++
flang/lib/Optimizer/CodeGen/CodeGen.cpp | 102 +++++++++++++++++-
2 files changed, 159 insertions(+), 1 deletion(-)
diff --git a/flang/include/flang/Optimizer/Dialect/FIROps.td b/flang/include/flang/Optimizer/Dialect/FIROps.td
index 8ac847dd7dd0a..2dff0f05fade7 100644
--- a/flang/include/flang/Optimizer/Dialect/FIROps.td
+++ b/flang/include/flang/Optimizer/Dialect/FIROps.td
@@ -517,6 +517,64 @@ def fir_ZeroOp : fir_OneResultOp<"zero_bits", [NoMemoryEffect]> {
let assemblyFormat = "type($intype) attr-dict";
}
+def fir_OmpTargetAllocMemOp : fir_Op<"omp_target_allocmem",
+ [MemoryEffects<[MemAlloc<DefaultResource>]>, AttrSizedOperandSegments]> {
+ let summary = "allocate storage on an openmp device for an object of a given type";
+
+ let description = [{
+ Creates a heap memory reference suitable for storing a value of the
+ given type, T. The heap refernce returned has type `!fir.heap<T>`.
+ The memory object is in an undefined state. `omp_target_allocmem` operations must
+ be paired with `omp_target_freemem` operations to avoid memory leaks.
+
+ ```
+ %0 = "fir.omp_target_allocmem"(%device, %type) : (i32, index) -> !fir.heap<!fir.array<?xf32>>
+ ```
+ }];
+
+ let arguments = (ins
+ Arg<AnyIntegerType>:$device,
+ TypeAttr:$in_type,
+ OptionalAttr<StrAttr>:$uniq_name,
+ OptionalAttr<StrAttr>:$bindc_name,
+ Variadic<AnyIntegerType>:$typeparams,
+ Variadic<AnyIntegerType>:$shape
+ );
+ let results = (outs fir_HeapType);
+
+ let extraClassDeclaration = [{
+ mlir::Type getAllocatedType();
+ bool hasLenParams() { return !getTypeparams().empty(); }
+ bool hasShapeOperands() { return !getShape().empty(); }
+ unsigned numLenParams() { return getTypeparams().size(); }
+ operand_range getLenParams() { return getTypeparams(); }
+ unsigned numShapeOperands() { return getShape().size(); }
+ operand_range getShapeOperands() { return getShape(); }
+ static mlir::Type getRefTy(mlir::Type ty);
+ }];
+}
+
+def fir_OmpTargetFreeMemOp : fir_Op<"omp_target_freemem",
+ [MemoryEffects<[MemFree]>]> {
+ let summary = "free a heap object";
+
+ let description = [{
+ Deallocates a heap memory reference that was allocated by an `omp_target_allocmem`.
+ The memory object that is deallocated is placed in an undefined state
+ after `fir.omp_target_freemem`.
+ ```
+ %0 = "fir.omp_target_allocmem"(%device, %type) : (i32, index) -> !fir.heap<!fir.array<?xf32>>
+ ...
+ "fir.omp_target_freemem"(%device, %0) : (i32, !fir.heap<!fir.array<?xf32>>) -> ()
+ ```
+ }];
+
+ let arguments = (ins
+ Arg<AnyIntegerType, "", [MemFree]>:$device,
+ Arg<fir_HeapType, "", [MemFree]>:$heapref
+ );
+}
+
//===----------------------------------------------------------------------===//
// Terminator operations
//===----------------------------------------------------------------------===//
diff --git a/flang/lib/Optimizer/CodeGen/CodeGen.cpp b/flang/lib/Optimizer/CodeGen/CodeGen.cpp
index a3de3ae9d116a..042ade6b1e0a1 100644
--- a/flang/lib/Optimizer/CodeGen/CodeGen.cpp
+++ b/flang/lib/Optimizer/CodeGen/CodeGen.cpp
@@ -1168,6 +1168,105 @@ struct FreeMemOpConversion : public fir::FIROpConversion<fir::FreeMemOp> {
};
} // namespace
+static mlir::LLVM::LLVMFuncOp getOmpTargetAlloc(mlir::Operation *op) {
+ auto module = op->getParentOfType<mlir::ModuleOp>();
+ if (mlir::LLVM::LLVMFuncOp mallocFunc =
+ module.lookupSymbol<mlir::LLVM::LLVMFuncOp>("omp_target_alloc"))
+ return mallocFunc;
+ mlir::OpBuilder moduleBuilder(module.getBodyRegion());
+ auto i64Ty = mlir::IntegerType::get(module->getContext(), 64);
+ auto i32Ty = mlir::IntegerType::get(module->getContext(), 32);
+ return moduleBuilder.create<mlir::LLVM::LLVMFuncOp>(
+ moduleBuilder.getUnknownLoc(), "omp_target_alloc",
+ mlir::LLVM::LLVMFunctionType::get(
+ mlir::LLVM::LLVMPointerType::get(module->getContext()),
+ {i64Ty, i32Ty},
+ /*isVarArg=*/false));
+}
+
+namespace {
+struct OmpTargetAllocMemOpConversion
+ : public fir::FIROpConversion<fir::OmpTargetAllocMemOp> {
+ using FIROpConversion::FIROpConversion;
+
+ mlir::LogicalResult
+ matchAndRewrite(fir::OmpTargetAllocMemOp heap, OpAdaptor adaptor,
+ mlir::ConversionPatternRewriter &rewriter) const override {
+ mlir::Type heapTy = heap.getType();
+ mlir::LLVM::LLVMFuncOp mallocFunc = getOmpTargetAlloc(heap);
+ mlir::Location loc = heap.getLoc();
+ auto ity = lowerTy().indexType();
+ mlir::Type dataTy = fir::unwrapRefType(heapTy);
+ mlir::Type llvmObjectTy = convertObjectType(dataTy);
+ if (fir::isRecordWithTypeParameters(fir::unwrapSequenceType(dataTy)))
+ TODO(loc, "fir.omp_target_allocmem codegen of derived type with length "
+ "parameters");
+ mlir::Value size = genTypeSizeInBytes(loc, ity, rewriter, llvmObjectTy);
+ if (auto scaleSize = genAllocationScaleSize(heap, ity, rewriter))
+ size = rewriter.create<mlir::LLVM::MulOp>(loc, ity, size, scaleSize);
+ for (mlir::Value opnd : adaptor.getOperands().drop_front())
+ size = rewriter.create<mlir::LLVM::MulOp>(
+ loc, ity, size, integerCast(loc, rewriter, ity, opnd));
+ auto mallocTyWidth = lowerTy().getIndexTypeBitwidth();
+ auto mallocTy =
+ mlir::IntegerType::get(rewriter.getContext(), mallocTyWidth);
+ if (mallocTyWidth != ity.getIntOrFloatBitWidth())
+ size = integerCast(loc, rewriter, mallocTy, size);
+ heap->setAttr("callee", mlir::SymbolRefAttr::get(mallocFunc));
+ rewriter.replaceOpWithNewOp<mlir::LLVM::CallOp>(
+ heap, ::getLlvmPtrType(heap.getContext()),
+ mlir::SmallVector<mlir::Value, 2>({size, heap.getDevice()}),
+ addLLVMOpBundleAttrs(rewriter, heap->getAttrs(), 2));
+ return mlir::success();
+ }
+
+ /// Compute the allocation size in bytes of the element type of
+ /// \p llTy pointer type. The result is returned as a value of \p idxTy
+ /// integer type.
+ mlir::Value genTypeSizeInBytes(mlir::Location loc, mlir::Type idxTy,
+ mlir::ConversionPatternRewriter &rewriter,
+ mlir::Type llTy) const {
+ return computeElementDistance(loc, llTy, idxTy, rewriter, getDataLayout());
+ }
+};
+} // namespace
+
+static mlir::LLVM::LLVMFuncOp getOmpTargetFree(mlir::Operation *op) {
+ auto module = op->getParentOfType<mlir::ModuleOp>();
+ if (mlir::LLVM::LLVMFuncOp freeFunc =
+ module.lookupSymbol<mlir::LLVM::LLVMFuncOp>("omp_target_free"))
+ return freeFunc;
+ mlir::OpBuilder moduleBuilder(module.getBodyRegion());
+ auto i32Ty = mlir::IntegerType::get(module->getContext(), 32);
+ return moduleBuilder.create<mlir::LLVM::LLVMFuncOp>(
+ moduleBuilder.getUnknownLoc(), "omp_target_free",
+ mlir::LLVM::LLVMFunctionType::get(
+ mlir::LLVM::LLVMVoidType::get(module->getContext()),
+ {getLlvmPtrType(module->getContext()), i32Ty},
+ /*isVarArg=*/false));
+}
+
+namespace {
+struct OmpTargetFreeMemOpConversion
+ : public fir::FIROpConversion<fir::OmpTargetFreeMemOp> {
+ using FIROpConversion::FIROpConversion;
+
+ mlir::LogicalResult
+ matchAndRewrite(fir::OmpTargetFreeMemOp freemem, OpAdaptor adaptor,
+ mlir::ConversionPatternRewriter &rewriter) const override {
+ mlir::LLVM::LLVMFuncOp freeFunc = getOmpTargetFree(freemem);
+ mlir::Location loc = freemem.getLoc();
+ freemem->setAttr("callee", mlir::SymbolRefAttr::get(freeFunc));
+ rewriter.create<mlir::LLVM::CallOp>(
+ loc, mlir::TypeRange{},
+ mlir::ValueRange{adaptor.getHeapref(), freemem.getDevice()},
+ addLLVMOpBundleAttrs(rewriter, freemem->getAttrs(), 2));
+ rewriter.eraseOp(freemem);
+ return mlir::success();
+ }
+};
+} // namespace
+
// Convert subcomponent array indices from column-major to row-major ordering.
static llvm::SmallVector<mlir::Value>
convertSubcomponentIndices(mlir::Location loc, mlir::Type eleTy,
@@ -4274,7 +4373,8 @@ void fir::populateFIRToLLVMConversionPatterns(
GlobalLenOpConversion, GlobalOpConversion, InsertOnRangeOpConversion,
IsPresentOpConversion, LenParamIndexOpConversion, LoadOpConversion,
LocalitySpecifierOpConversion, MulcOpConversion, NegcOpConversion,
- NoReassocOpConversion, SelectCaseOpConversion, SelectOpConversion,
+ NoReassocOpConversion, OmpTargetAllocMemOpConversion,
+ OmpTargetFreeMemOpConversion, SelectCaseOpConversion, SelectOpConversion,
SelectRankOpConversion, SelectTypeOpConversion, ShapeOpConversion,
ShapeShiftOpConversion, ShiftOpConversion, SliceOpConversion,
StoreOpConversion, StringLitOpConversion, SubcOpConversion,
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