//===- GPUOpsLowering.cpp - GPU FuncOp / ReturnOp lowering ----------------===// // // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. // See https://llvm.org/LICENSE.txt for license information. // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception // //===----------------------------------------------------------------------===// #include "GPUOpsLowering.h" #include "mlir/Dialect/LLVMIR/LLVMDialect.h" #include "mlir/IR/Attributes.h" #include "mlir/IR/Builders.h" #include "mlir/IR/BuiltinTypes.h" #include "llvm/ADT/SmallVectorExtras.h" #include "llvm/Support/FormatVariadic.h" using namespace mlir; LogicalResult GPUFuncOpLowering::matchAndRewrite(gpu::GPUFuncOp gpuFuncOp, OpAdaptor adaptor, ConversionPatternRewriter &rewriter) const { Location loc = gpuFuncOp.getLoc(); SmallVector workgroupBuffers; workgroupBuffers.reserve(gpuFuncOp.getNumWorkgroupAttributions()); for (const auto &en : llvm::enumerate(gpuFuncOp.getWorkgroupAttributions())) { BlockArgument attribution = en.value(); auto type = dyn_cast(attribution.getType()); assert(type && type.hasStaticShape() && "unexpected type in attribution"); uint64_t numElements = type.getNumElements(); auto elementType = cast(typeConverter->convertType(type.getElementType())); auto arrayType = LLVM::LLVMArrayType::get(elementType, numElements); std::string name = std::string( llvm::formatv("__wg_{0}_{1}", gpuFuncOp.getName(), en.index())); uint64_t alignment = 0; if (auto alignAttr = dyn_cast_or_null(gpuFuncOp.getWorkgroupAttributionAttr( en.index(), LLVM::LLVMDialect::getAlignAttrName()))) alignment = alignAttr.getInt(); auto globalOp = rewriter.create( gpuFuncOp.getLoc(), arrayType, /*isConstant=*/false, LLVM::Linkage::Internal, name, /*value=*/Attribute(), alignment, workgroupAddrSpace); workgroupBuffers.push_back(globalOp); } // Remap proper input types. TypeConverter::SignatureConversion signatureConversion( gpuFuncOp.front().getNumArguments()); Type funcType = getTypeConverter()->convertFunctionSignature( gpuFuncOp.getFunctionType(), /*isVariadic=*/false, getTypeConverter()->getOptions().useBarePtrCallConv, signatureConversion); // Create the new function operation. Only copy those attributes that are // not specific to function modeling. SmallVector attributes; for (const auto &attr : gpuFuncOp->getAttrs()) { if (attr.getName() == SymbolTable::getSymbolAttrName() || attr.getName() == gpuFuncOp.getFunctionTypeAttrName() || attr.getName() == gpu::GPUFuncOp::getNumWorkgroupAttributionsAttrName() || attr.getName() == gpuFuncOp.getWorkgroupAttribAttrsAttrName() || attr.getName() == gpuFuncOp.getPrivateAttribAttrsAttrName()) continue; attributes.push_back(attr); } // Add a dialect specific kernel attribute in addition to GPU kernel // attribute. The former is necessary for further translation while the // latter is expected by gpu.launch_func. if (gpuFuncOp.isKernel()) attributes.emplace_back(kernelAttributeName, rewriter.getUnitAttr()); auto llvmFuncOp = rewriter.create( gpuFuncOp.getLoc(), gpuFuncOp.getName(), funcType, LLVM::Linkage::External, /*dsoLocal*/ false, /*cconv*/ LLVM::CConv::C, attributes); { // Insert operations that correspond to converted workgroup and private // memory attributions to the body of the function. This must operate on // the original function, before the body region is inlined in the new // function to maintain the relation between block arguments and the // parent operation that assigns their semantics. OpBuilder::InsertionGuard guard(rewriter); // Rewrite workgroup memory attributions to addresses of global buffers. rewriter.setInsertionPointToStart(&gpuFuncOp.front()); unsigned numProperArguments = gpuFuncOp.getNumArguments(); for (const auto &en : llvm::enumerate(workgroupBuffers)) { LLVM::GlobalOp global = en.value(); Value address = rewriter.create( loc, getTypeConverter()->getPointerType(global.getType(), global.getAddrSpace()), global.getSymNameAttr()); auto elementType = cast(global.getType()).getElementType(); Value memory = rewriter.create( loc, getTypeConverter()->getPointerType(elementType, global.getAddrSpace()), global.getType(), address, ArrayRef{0, 0}); // Build a memref descriptor pointing to the buffer to plug with the // existing memref infrastructure. This may use more registers than // otherwise necessary given that memref sizes are fixed, but we can try // and canonicalize that away later. Value attribution = gpuFuncOp.getWorkgroupAttributions()[en.index()]; auto type = cast(attribution.getType()); auto descr = MemRefDescriptor::fromStaticShape( rewriter, loc, *getTypeConverter(), type, memory); signatureConversion.remapInput(numProperArguments + en.index(), descr); } // Rewrite private memory attributions to alloca'ed buffers. unsigned numWorkgroupAttributions = gpuFuncOp.getNumWorkgroupAttributions(); auto int64Ty = IntegerType::get(rewriter.getContext(), 64); for (const auto &en : llvm::enumerate(gpuFuncOp.getPrivateAttributions())) { Value attribution = en.value(); auto type = cast(attribution.getType()); assert(type && type.hasStaticShape() && "unexpected type in attribution"); // Explicitly drop memory space when lowering private memory // attributions since NVVM models it as `alloca`s in the default // memory space and does not support `alloca`s with addrspace(5). Type elementType = typeConverter->convertType(type.getElementType()); auto ptrType = getTypeConverter()->getPointerType(elementType, allocaAddrSpace); Value numElements = rewriter.create( gpuFuncOp.getLoc(), int64Ty, type.getNumElements()); uint64_t alignment = 0; if (auto alignAttr = dyn_cast_or_null(gpuFuncOp.getPrivateAttributionAttr( en.index(), LLVM::LLVMDialect::getAlignAttrName()))) alignment = alignAttr.getInt(); Value allocated = rewriter.create( gpuFuncOp.getLoc(), ptrType, elementType, numElements, alignment); auto descr = MemRefDescriptor::fromStaticShape( rewriter, loc, *getTypeConverter(), type, allocated); signatureConversion.remapInput( numProperArguments + numWorkgroupAttributions + en.index(), descr); } } // Move the region to the new function, update the entry block signature. rewriter.inlineRegionBefore(gpuFuncOp.getBody(), llvmFuncOp.getBody(), llvmFuncOp.end()); if (failed(rewriter.convertRegionTypes(&llvmFuncOp.getBody(), *typeConverter, &signatureConversion))) return failure(); // If bare memref pointers are being used, remap them back to memref // descriptors This must be done after signature conversion to get rid of the // unrealized casts. if (getTypeConverter()->getOptions().useBarePtrCallConv) { OpBuilder::InsertionGuard guard(rewriter); rewriter.setInsertionPointToStart(&llvmFuncOp.getBody().front()); for (const auto &en : llvm::enumerate(gpuFuncOp.getArgumentTypes())) { auto memrefTy = dyn_cast(en.value()); if (!memrefTy) continue; assert(memrefTy.hasStaticShape() && "Bare pointer convertion used with dynamically-shaped memrefs"); // Use a placeholder when replacing uses of the memref argument to prevent // circular replacements. auto remapping = signatureConversion.getInputMapping(en.index()); assert(remapping && remapping->size == 1 && "Type converter should produce 1-to-1 mapping for bare memrefs"); BlockArgument newArg = llvmFuncOp.getBody().getArgument(remapping->inputNo); auto placeholder = rewriter.create( loc, getTypeConverter()->convertType(memrefTy)); rewriter.replaceUsesOfBlockArgument(newArg, placeholder); Value desc = MemRefDescriptor::fromStaticShape( rewriter, loc, *getTypeConverter(), memrefTy, newArg); rewriter.replaceOp(placeholder, {desc}); } } rewriter.eraseOp(gpuFuncOp); return success(); } static SmallString<16> getUniqueFormatGlobalName(gpu::GPUModuleOp moduleOp) { const char formatStringPrefix[] = "printfFormat_"; // Get a unique global name. unsigned stringNumber = 0; SmallString<16> stringConstName; do { stringConstName.clear(); (formatStringPrefix + Twine(stringNumber++)).toStringRef(stringConstName); } while (moduleOp.lookupSymbol(stringConstName)); return stringConstName; } template static LLVM::LLVMFuncOp getOrDefineFunction(T &moduleOp, const Location loc, ConversionPatternRewriter &rewriter, StringRef name, LLVM::LLVMFunctionType type) { LLVM::LLVMFuncOp ret; if (!(ret = moduleOp.template lookupSymbol(name))) { ConversionPatternRewriter::InsertionGuard guard(rewriter); rewriter.setInsertionPointToStart(moduleOp.getBody()); ret = rewriter.create(loc, name, type, LLVM::Linkage::External); } return ret; } LogicalResult GPUPrintfOpToHIPLowering::matchAndRewrite( gpu::PrintfOp gpuPrintfOp, gpu::PrintfOpAdaptor adaptor, ConversionPatternRewriter &rewriter) const { Location loc = gpuPrintfOp->getLoc(); mlir::Type llvmI8 = typeConverter->convertType(rewriter.getI8Type()); mlir::Type i8Ptr = getTypeConverter()->getPointerType(llvmI8); mlir::Type llvmI32 = typeConverter->convertType(rewriter.getI32Type()); mlir::Type llvmI64 = typeConverter->convertType(rewriter.getI64Type()); // Note: this is the GPUModule op, not the ModuleOp that surrounds it // This ensures that global constants and declarations are placed within // the device code, not the host code auto moduleOp = gpuPrintfOp->getParentOfType(); auto ocklBegin = getOrDefineFunction(moduleOp, loc, rewriter, "__ockl_printf_begin", LLVM::LLVMFunctionType::get(llvmI64, {llvmI64})); LLVM::LLVMFuncOp ocklAppendArgs; if (!adaptor.getArgs().empty()) { ocklAppendArgs = getOrDefineFunction( moduleOp, loc, rewriter, "__ockl_printf_append_args", LLVM::LLVMFunctionType::get( llvmI64, {llvmI64, /*numArgs*/ llvmI32, llvmI64, llvmI64, llvmI64, llvmI64, llvmI64, llvmI64, llvmI64, /*isLast*/ llvmI32})); } auto ocklAppendStringN = getOrDefineFunction( moduleOp, loc, rewriter, "__ockl_printf_append_string_n", LLVM::LLVMFunctionType::get( llvmI64, {llvmI64, i8Ptr, /*length (bytes)*/ llvmI64, /*isLast*/ llvmI32})); /// Start the printf hostcall Value zeroI64 = rewriter.create(loc, llvmI64, 0); auto printfBeginCall = rewriter.create(loc, ocklBegin, zeroI64); Value printfDesc = printfBeginCall.getResult(); // Get a unique global name for the format. SmallString<16> stringConstName = getUniqueFormatGlobalName(moduleOp); llvm::SmallString<20> formatString(adaptor.getFormat()); formatString.push_back('\0'); // Null terminate for C size_t formatStringSize = formatString.size_in_bytes(); auto globalType = LLVM::LLVMArrayType::get(llvmI8, formatStringSize); LLVM::GlobalOp global; { ConversionPatternRewriter::InsertionGuard guard(rewriter); rewriter.setInsertionPointToStart(moduleOp.getBody()); global = rewriter.create( loc, globalType, /*isConstant=*/true, LLVM::Linkage::Internal, stringConstName, rewriter.getStringAttr(formatString)); } // Get a pointer to the format string's first element and pass it to printf() Value globalPtr = rewriter.create( loc, getTypeConverter()->getPointerType(globalType, global.getAddrSpace()), global.getSymNameAttr()); Value stringStart = rewriter.create( loc, i8Ptr, globalType, globalPtr, ArrayRef{0, 0}); Value stringLen = rewriter.create(loc, llvmI64, formatStringSize); Value oneI32 = rewriter.create(loc, llvmI32, 1); Value zeroI32 = rewriter.create(loc, llvmI32, 0); auto appendFormatCall = rewriter.create( loc, ocklAppendStringN, ValueRange{printfDesc, stringStart, stringLen, adaptor.getArgs().empty() ? oneI32 : zeroI32}); printfDesc = appendFormatCall.getResult(); // __ockl_printf_append_args takes 7 values per append call constexpr size_t argsPerAppend = 7; size_t nArgs = adaptor.getArgs().size(); for (size_t group = 0; group < nArgs; group += argsPerAppend) { size_t bound = std::min(group + argsPerAppend, nArgs); size_t numArgsThisCall = bound - group; SmallVector arguments; arguments.push_back(printfDesc); arguments.push_back( rewriter.create(loc, llvmI32, numArgsThisCall)); for (size_t i = group; i < bound; ++i) { Value arg = adaptor.getArgs()[i]; if (auto floatType = dyn_cast(arg.getType())) { if (!floatType.isF64()) arg = rewriter.create( loc, typeConverter->convertType(rewriter.getF64Type()), arg); arg = rewriter.create(loc, llvmI64, arg); } if (arg.getType().getIntOrFloatBitWidth() != 64) arg = rewriter.create(loc, llvmI64, arg); arguments.push_back(arg); } // Pad out to 7 arguments since the hostcall always needs 7 for (size_t extra = numArgsThisCall; extra < argsPerAppend; ++extra) { arguments.push_back(zeroI64); } auto isLast = (bound == nArgs) ? oneI32 : zeroI32; arguments.push_back(isLast); auto call = rewriter.create(loc, ocklAppendArgs, arguments); printfDesc = call.getResult(); } rewriter.eraseOp(gpuPrintfOp); return success(); } LogicalResult GPUPrintfOpToLLVMCallLowering::matchAndRewrite( gpu::PrintfOp gpuPrintfOp, gpu::PrintfOpAdaptor adaptor, ConversionPatternRewriter &rewriter) const { Location loc = gpuPrintfOp->getLoc(); mlir::Type llvmI8 = typeConverter->convertType(rewriter.getIntegerType(8)); mlir::Type i8Ptr = getTypeConverter()->getPointerType(llvmI8, addressSpace); // Note: this is the GPUModule op, not the ModuleOp that surrounds it // This ensures that global constants and declarations are placed within // the device code, not the host code auto moduleOp = gpuPrintfOp->getParentOfType(); auto printfType = LLVM::LLVMFunctionType::get(rewriter.getI32Type(), {i8Ptr}, /*isVarArg=*/true); LLVM::LLVMFuncOp printfDecl = getOrDefineFunction(moduleOp, loc, rewriter, "printf", printfType); // Get a unique global name for the format. SmallString<16> stringConstName = getUniqueFormatGlobalName(moduleOp); llvm::SmallString<20> formatString(adaptor.getFormat()); formatString.push_back('\0'); // Null terminate for C auto globalType = LLVM::LLVMArrayType::get(llvmI8, formatString.size_in_bytes()); LLVM::GlobalOp global; { ConversionPatternRewriter::InsertionGuard guard(rewriter); rewriter.setInsertionPointToStart(moduleOp.getBody()); global = rewriter.create( loc, globalType, /*isConstant=*/true, LLVM::Linkage::Internal, stringConstName, rewriter.getStringAttr(formatString), /*allignment=*/0, addressSpace); } // Get a pointer to the format string's first element Value globalPtr = rewriter.create( loc, getTypeConverter()->getPointerType(globalType, global.getAddrSpace()), global.getSymNameAttr()); Value stringStart = rewriter.create( loc, i8Ptr, globalType, globalPtr, ArrayRef{0, 0}); // Construct arguments and function call auto argsRange = adaptor.getArgs(); SmallVector printfArgs; printfArgs.reserve(argsRange.size() + 1); printfArgs.push_back(stringStart); printfArgs.append(argsRange.begin(), argsRange.end()); rewriter.create(loc, printfDecl, printfArgs); rewriter.eraseOp(gpuPrintfOp); return success(); } LogicalResult GPUPrintfOpToVPrintfLowering::matchAndRewrite( gpu::PrintfOp gpuPrintfOp, gpu::PrintfOpAdaptor adaptor, ConversionPatternRewriter &rewriter) const { Location loc = gpuPrintfOp->getLoc(); mlir::Type llvmI8 = typeConverter->convertType(rewriter.getIntegerType(8)); mlir::Type i8Ptr = LLVM::LLVMPointerType::get(llvmI8); // Note: this is the GPUModule op, not the ModuleOp that surrounds it // This ensures that global constants and declarations are placed within // the device code, not the host code auto moduleOp = gpuPrintfOp->getParentOfType(); auto vprintfType = LLVM::LLVMFunctionType::get(rewriter.getI32Type(), {i8Ptr, i8Ptr}); LLVM::LLVMFuncOp vprintfDecl = getOrDefineFunction(moduleOp, loc, rewriter, "vprintf", vprintfType); // Get a unique global name for the format. SmallString<16> stringConstName = getUniqueFormatGlobalName(moduleOp); llvm::SmallString<20> formatString(adaptor.getFormat()); formatString.push_back('\0'); // Null terminate for C auto globalType = LLVM::LLVMArrayType::get(llvmI8, formatString.size_in_bytes()); LLVM::GlobalOp global; { ConversionPatternRewriter::InsertionGuard guard(rewriter); rewriter.setInsertionPointToStart(moduleOp.getBody()); global = rewriter.create( loc, globalType, /*isConstant=*/true, LLVM::Linkage::Internal, stringConstName, rewriter.getStringAttr(formatString), /*allignment=*/0); } // Get a pointer to the format string's first element Value globalPtr = rewriter.create(loc, global); Value stringStart = rewriter.create( loc, i8Ptr, globalPtr, ArrayRef{0, 0}); SmallVector types; SmallVector args; // Promote and pack the arguments into a stack allocation. for (Value arg : adaptor.getArgs()) { Type type = arg.getType(); Value promotedArg = arg; assert(type.isIntOrFloat()); if (isa(type)) { type = rewriter.getF64Type(); promotedArg = rewriter.create(loc, type, arg); } types.push_back(type); args.push_back(promotedArg); } Type structType = LLVM::LLVMStructType::getLiteral(gpuPrintfOp.getContext(), types); Type structPtrType = LLVM::LLVMPointerType::get(structType); Value one = rewriter.create(loc, rewriter.getI64Type(), rewriter.getIndexAttr(1)); Value tempAlloc = rewriter.create(loc, structPtrType, one, /*alignment=*/0); for (auto [index, arg] : llvm::enumerate(args)) { Value ptr = rewriter.create( loc, LLVM::LLVMPointerType::get(arg.getType()), tempAlloc, ArrayRef{0, index}); rewriter.create(loc, arg, ptr); } tempAlloc = rewriter.create(loc, i8Ptr, tempAlloc); std::array printfArgs = {stringStart, tempAlloc}; rewriter.create(loc, vprintfDecl, printfArgs); rewriter.eraseOp(gpuPrintfOp); return success(); } /// Unrolls op if it's operating on vectors. LogicalResult impl::scalarizeVectorOp(Operation *op, ValueRange operands, ConversionPatternRewriter &rewriter, LLVMTypeConverter &converter) { TypeRange operandTypes(operands); if (llvm::none_of(operandTypes, [](Type type) { return isa(type); })) { return rewriter.notifyMatchFailure(op, "expected vector operand"); } if (op->getNumRegions() != 0 || op->getNumSuccessors() != 0) return rewriter.notifyMatchFailure(op, "expected no region/successor"); if (op->getNumResults() != 1) return rewriter.notifyMatchFailure(op, "expected single result"); VectorType vectorType = dyn_cast(op->getResult(0).getType()); if (!vectorType) return rewriter.notifyMatchFailure(op, "expected vector result"); Location loc = op->getLoc(); Value result = rewriter.create(loc, vectorType); Type indexType = converter.convertType(rewriter.getIndexType()); StringAttr name = op->getName().getIdentifier(); Type elementType = vectorType.getElementType(); for (int64_t i = 0; i < vectorType.getNumElements(); ++i) { Value index = rewriter.create(loc, indexType, i); auto extractElement = [&](Value operand) -> Value { if (!isa(operand.getType())) return operand; return rewriter.create(loc, operand, index); }; auto scalarOperands = llvm::map_to_vector(operands, extractElement); Operation *scalarOp = rewriter.create(loc, name, scalarOperands, elementType, op->getAttrs()); rewriter.create(loc, result, scalarOp->getResult(0), index); } rewriter.replaceOp(op, result); return success(); } static IntegerAttr wrapNumericMemorySpace(MLIRContext *ctx, unsigned space) { return IntegerAttr::get(IntegerType::get(ctx, 64), space); } void mlir::populateGpuMemorySpaceAttributeConversions( TypeConverter &typeConverter, const MemorySpaceMapping &mapping) { typeConverter.addTypeAttributeConversion( [mapping](BaseMemRefType type, gpu::AddressSpaceAttr memorySpaceAttr) { gpu::AddressSpace memorySpace = memorySpaceAttr.getValue(); unsigned addressSpace = mapping(memorySpace); return wrapNumericMemorySpace(memorySpaceAttr.getContext(), addressSpace); }); }