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llvm-project/mlir/lib/Target/LLVMIR/ModuleImport.cpp
Tobias Gysi cf487cce6f [mlir][llvm] Make the import of LLVM IR intrinsics extensible. 
The revision introduces the LLVMImportDialectInterface to make the
import of LLVM IR intrinsics extensible. It uses a dialect interface
that enables external projects to provide their own conversion functions
for custom intrinsics. These conversion functions can rely on the
ModuleImport class to perform support tasks such as mapping LLVM
values to MLIR values or for converting types between the two worlds.

The implementation largely mirrors the export implementation. One major
difference is the dispatch to the appropriate dialect interface, since
LLVM IR intrinsics have no direct association to an MLIR dialect. The
dialect interfaces thus have to publish the supported intrinsics to
ensure incoming conversion calls are dispatched to the right dialect
interface.

The revision implements the extensible intrinsic import discussed as
part of the "extensible llvm ir import" rfc:
https://discourse.llvm.org/t/rfc-extensible-llvm-ir-import/67256/6

Reviewed By: ftynse

Differential Revision: https://reviews.llvm.org/D140374
2023-01-02 11:35:44 +01:00

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//===- ModuleImport.cpp - LLVM to MLIR conversion ---------------*- C++ -*-===//
//
// 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
//
//===----------------------------------------------------------------------===//
//
// This file implements the import of an LLVM IR module into an LLVM dialect
// module.
//
//===----------------------------------------------------------------------===//
#include "mlir/Target/LLVMIR/ModuleImport.h"
#include "mlir/Target/LLVMIR/Import.h"
#include "DebugImporter.h"
#include "mlir/Dialect/DLTI/DLTI.h"
#include "mlir/Dialect/LLVMIR/LLVMDialect.h"
#include "mlir/IR/Matchers.h"
#include "mlir/Interfaces/DataLayoutInterfaces.h"
#include "mlir/Tools/mlir-translate/Translation.h"
#include "llvm/ADT/PostOrderIterator.h"
#include "llvm/ADT/ScopeExit.h"
#include "llvm/ADT/StringSet.h"
#include "llvm/IR/Constants.h"
#include "llvm/IR/InlineAsm.h"
#include "llvm/IR/Instructions.h"
#include "llvm/IR/IntrinsicInst.h"
#include "llvm/IR/Operator.h"
using namespace mlir;
using namespace mlir::LLVM;
using namespace mlir::LLVM::detail;
#include "mlir/Dialect/LLVMIR/LLVMConversionEnumsFromLLVM.inc"
// Utility to print an LLVM value as a string for passing to emitError().
// FIXME: Diagnostic should be able to natively handle types that have
// operator << (raw_ostream&) defined.
static std::string diag(llvm::Value &value) {
std::string str;
llvm::raw_string_ostream os(str);
os << value;
return os.str();
}
/// Creates an attribute containing ABI and preferred alignment numbers parsed
/// a string. The string may be either "abi:preferred" or just "abi". In the
/// latter case, the preferred alignment is considered equal to ABI alignment.
static DenseIntElementsAttr parseDataLayoutAlignment(MLIRContext &ctx,
StringRef spec) {
auto i32 = IntegerType::get(&ctx, 32);
StringRef abiString, preferredString;
std::tie(abiString, preferredString) = spec.split(':');
int abi, preferred;
if (abiString.getAsInteger(/*Radix=*/10, abi))
return nullptr;
if (preferredString.empty())
preferred = abi;
else if (preferredString.getAsInteger(/*Radix=*/10, preferred))
return nullptr;
return DenseIntElementsAttr::get(VectorType::get({2}, i32), {abi, preferred});
}
/// Returns a supported MLIR floating point type of the given bit width or null
/// if the bit width is not supported.
static FloatType getDLFloatType(MLIRContext &ctx, int32_t bitwidth) {
switch (bitwidth) {
case 16:
return FloatType::getF16(&ctx);
case 32:
return FloatType::getF32(&ctx);
case 64:
return FloatType::getF64(&ctx);
case 80:
return FloatType::getF80(&ctx);
case 128:
return FloatType::getF128(&ctx);
default:
return nullptr;
}
}
static ICmpPredicate getICmpPredicate(llvm::CmpInst::Predicate pred) {
switch (pred) {
default:
llvm_unreachable("incorrect comparison predicate");
case llvm::CmpInst::Predicate::ICMP_EQ:
return LLVM::ICmpPredicate::eq;
case llvm::CmpInst::Predicate::ICMP_NE:
return LLVM::ICmpPredicate::ne;
case llvm::CmpInst::Predicate::ICMP_SLT:
return LLVM::ICmpPredicate::slt;
case llvm::CmpInst::Predicate::ICMP_SLE:
return LLVM::ICmpPredicate::sle;
case llvm::CmpInst::Predicate::ICMP_SGT:
return LLVM::ICmpPredicate::sgt;
case llvm::CmpInst::Predicate::ICMP_SGE:
return LLVM::ICmpPredicate::sge;
case llvm::CmpInst::Predicate::ICMP_ULT:
return LLVM::ICmpPredicate::ult;
case llvm::CmpInst::Predicate::ICMP_ULE:
return LLVM::ICmpPredicate::ule;
case llvm::CmpInst::Predicate::ICMP_UGT:
return LLVM::ICmpPredicate::ugt;
case llvm::CmpInst::Predicate::ICMP_UGE:
return LLVM::ICmpPredicate::uge;
}
llvm_unreachable("incorrect integer comparison predicate");
}
static FCmpPredicate getFCmpPredicate(llvm::CmpInst::Predicate pred) {
switch (pred) {
default:
llvm_unreachable("incorrect comparison predicate");
case llvm::CmpInst::Predicate::FCMP_FALSE:
return LLVM::FCmpPredicate::_false;
case llvm::CmpInst::Predicate::FCMP_TRUE:
return LLVM::FCmpPredicate::_true;
case llvm::CmpInst::Predicate::FCMP_OEQ:
return LLVM::FCmpPredicate::oeq;
case llvm::CmpInst::Predicate::FCMP_ONE:
return LLVM::FCmpPredicate::one;
case llvm::CmpInst::Predicate::FCMP_OLT:
return LLVM::FCmpPredicate::olt;
case llvm::CmpInst::Predicate::FCMP_OLE:
return LLVM::FCmpPredicate::ole;
case llvm::CmpInst::Predicate::FCMP_OGT:
return LLVM::FCmpPredicate::ogt;
case llvm::CmpInst::Predicate::FCMP_OGE:
return LLVM::FCmpPredicate::oge;
case llvm::CmpInst::Predicate::FCMP_ORD:
return LLVM::FCmpPredicate::ord;
case llvm::CmpInst::Predicate::FCMP_ULT:
return LLVM::FCmpPredicate::ult;
case llvm::CmpInst::Predicate::FCMP_ULE:
return LLVM::FCmpPredicate::ule;
case llvm::CmpInst::Predicate::FCMP_UGT:
return LLVM::FCmpPredicate::ugt;
case llvm::CmpInst::Predicate::FCMP_UGE:
return LLVM::FCmpPredicate::uge;
case llvm::CmpInst::Predicate::FCMP_UNO:
return LLVM::FCmpPredicate::uno;
case llvm::CmpInst::Predicate::FCMP_UEQ:
return LLVM::FCmpPredicate::ueq;
case llvm::CmpInst::Predicate::FCMP_UNE:
return LLVM::FCmpPredicate::une;
}
llvm_unreachable("incorrect floating point comparison predicate");
}
static AtomicOrdering getLLVMAtomicOrdering(llvm::AtomicOrdering ordering) {
switch (ordering) {
case llvm::AtomicOrdering::NotAtomic:
return LLVM::AtomicOrdering::not_atomic;
case llvm::AtomicOrdering::Unordered:
return LLVM::AtomicOrdering::unordered;
case llvm::AtomicOrdering::Monotonic:
return LLVM::AtomicOrdering::monotonic;
case llvm::AtomicOrdering::Acquire:
return LLVM::AtomicOrdering::acquire;
case llvm::AtomicOrdering::Release:
return LLVM::AtomicOrdering::release;
case llvm::AtomicOrdering::AcquireRelease:
return LLVM::AtomicOrdering::acq_rel;
case llvm::AtomicOrdering::SequentiallyConsistent:
return LLVM::AtomicOrdering::seq_cst;
}
llvm_unreachable("incorrect atomic ordering");
}
static AtomicBinOp getLLVMAtomicBinOp(llvm::AtomicRMWInst::BinOp binOp) {
switch (binOp) {
case llvm::AtomicRMWInst::Xchg:
return LLVM::AtomicBinOp::xchg;
case llvm::AtomicRMWInst::Add:
return LLVM::AtomicBinOp::add;
case llvm::AtomicRMWInst::Sub:
return LLVM::AtomicBinOp::sub;
case llvm::AtomicRMWInst::And:
return LLVM::AtomicBinOp::_and;
case llvm::AtomicRMWInst::Nand:
return LLVM::AtomicBinOp::nand;
case llvm::AtomicRMWInst::Or:
return LLVM::AtomicBinOp::_or;
case llvm::AtomicRMWInst::Xor:
return LLVM::AtomicBinOp::_xor;
case llvm::AtomicRMWInst::Max:
return LLVM::AtomicBinOp::max;
case llvm::AtomicRMWInst::Min:
return LLVM::AtomicBinOp::min;
case llvm::AtomicRMWInst::UMax:
return LLVM::AtomicBinOp::umax;
case llvm::AtomicRMWInst::UMin:
return LLVM::AtomicBinOp::umin;
case llvm::AtomicRMWInst::FAdd:
return LLVM::AtomicBinOp::fadd;
case llvm::AtomicRMWInst::FSub:
return LLVM::AtomicBinOp::fsub;
default:
llvm_unreachable("unsupported atomic binary operation");
}
}
/// Converts the sync scope identifier of `fenceInst` to the string
/// representation necessary to build the LLVM dialect fence operation.
static StringRef getLLVMSyncScope(llvm::FenceInst *fenceInst) {
llvm::LLVMContext &llvmContext = fenceInst->getContext();
SmallVector<StringRef> syncScopeNames;
llvmContext.getSyncScopeNames(syncScopeNames);
for (StringRef name : syncScopeNames)
if (fenceInst->getSyncScopeID() == llvmContext.getOrInsertSyncScopeID(name))
return name;
llvm_unreachable("incorrect sync scope identifier");
}
/// Converts an array of unsigned indices to a signed integer position array.
static SmallVector<int64_t> getPositionFromIndices(ArrayRef<unsigned> indices) {
SmallVector<int64_t> position;
llvm::append_range(position, indices);
return position;
}
/// Translate the given LLVM data layout into an MLIR equivalent using the DLTI
/// dialect.
DataLayoutSpecInterface
mlir::translateDataLayout(const llvm::DataLayout &dataLayout,
MLIRContext *context) {
assert(context && "expected MLIR context");
std::string layoutstr = dataLayout.getStringRepresentation();
// Remaining unhandled default layout defaults
// e (little endian if not set)
// p[n]:64:64:64 (non zero address spaces have 64-bit properties)
std::string append =
"p:64:64:64-S0-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f16:16:16-f64:"
"64:64-f128:128:128-v64:64:64-v128:128:128-a:0:64";
if (layoutstr.empty())
layoutstr = append;
else
layoutstr = layoutstr + "-" + append;
StringRef layout(layoutstr);
SmallVector<DataLayoutEntryInterface> entries;
StringSet<> seen;
while (!layout.empty()) {
// Split at '-'.
std::pair<StringRef, StringRef> split = layout.split('-');
StringRef current;
std::tie(current, layout) = split;
// Split at ':'.
StringRef kind, spec;
std::tie(kind, spec) = current.split(':');
if (seen.contains(kind))
continue;
seen.insert(kind);
char symbol = kind.front();
StringRef parameter = kind.substr(1);
if (symbol == 'i' || symbol == 'f') {
unsigned bitwidth;
if (parameter.getAsInteger(/*Radix=*/10, bitwidth))
return nullptr;
DenseIntElementsAttr params = parseDataLayoutAlignment(*context, spec);
if (!params)
return nullptr;
auto entry = DataLayoutEntryAttr::get(
symbol == 'i' ? static_cast<Type>(IntegerType::get(context, bitwidth))
: getDLFloatType(*context, bitwidth),
params);
entries.emplace_back(entry);
} else if (symbol == 'e' || symbol == 'E') {
auto value = StringAttr::get(
context, symbol == 'e' ? DLTIDialect::kDataLayoutEndiannessLittle
: DLTIDialect::kDataLayoutEndiannessBig);
auto entry = DataLayoutEntryAttr::get(
StringAttr::get(context, DLTIDialect::kDataLayoutEndiannessKey),
value);
entries.emplace_back(entry);
}
}
return DataLayoutSpecAttr::get(context, entries);
}
/// Get a topologically sorted list of blocks for the given function.
static SetVector<llvm::BasicBlock *>
getTopologicallySortedBlocks(llvm::Function *func) {
SetVector<llvm::BasicBlock *> blocks;
for (llvm::BasicBlock &bb : *func) {
if (blocks.count(&bb) == 0) {
llvm::ReversePostOrderTraversal<llvm::BasicBlock *> traversal(&bb);
blocks.insert(traversal.begin(), traversal.end());
}
}
assert(blocks.size() == func->size() && "some blocks are not sorted");
return blocks;
}
ModuleImport::ModuleImport(ModuleOp mlirModule,
std::unique_ptr<llvm::Module> llvmModule)
: builder(mlirModule->getContext()), context(mlirModule->getContext()),
mlirModule(mlirModule), llvmModule(std::move(llvmModule)),
iface(mlirModule->getContext()),
typeTranslator(*mlirModule->getContext()),
debugImporter(std::make_unique<DebugImporter>(mlirModule->getContext())) {
builder.setInsertionPointToStart(mlirModule.getBody());
}
LogicalResult ModuleImport::convertGlobals() {
for (llvm::GlobalVariable &globalVar : llvmModule->globals())
if (!processGlobal(&globalVar))
return failure();
return success();
}
LogicalResult ModuleImport::convertFunctions() {
for (llvm::Function &func : llvmModule->functions())
if (failed(processFunction(&func)))
return failure();
return success();
}
void ModuleImport::setFastmathFlagsAttr(llvm::Instruction *inst,
Operation *op) const {
auto iface = cast<FastmathFlagsInterface>(op);
// Even if the imported operation implements the fastmath interface, the
// original instruction may not have fastmath flags set. Exit if an
// instruction, such as a non floating-point function call, does not have
// fastmath flags.
if (!isa<llvm::FPMathOperator>(inst))
return;
llvm::FastMathFlags flags = inst->getFastMathFlags();
// Set the fastmath bits flag-by-flag.
FastmathFlags value = {};
value = bitEnumSet(value, FastmathFlags::nnan, flags.noNaNs());
value = bitEnumSet(value, FastmathFlags::ninf, flags.noInfs());
value = bitEnumSet(value, FastmathFlags::nsz, flags.noSignedZeros());
value = bitEnumSet(value, FastmathFlags::arcp, flags.allowReciprocal());
value = bitEnumSet(value, FastmathFlags::contract, flags.allowContract());
value = bitEnumSet(value, FastmathFlags::afn, flags.approxFunc());
value = bitEnumSet(value, FastmathFlags::reassoc, flags.allowReassoc());
FastmathFlagsAttr attr = FastmathFlagsAttr::get(builder.getContext(), value);
iface->setAttr(iface.getFastmathAttrName(), attr);
}
// We only need integers, floats, doubles, and vectors and tensors thereof for
// attributes. Scalar and vector types are converted to the standard
// equivalents. Array types are converted to ranked tensors; nested array types
// are converted to multi-dimensional tensors or vectors, depending on the
// innermost type being a scalar or a vector.
Type ModuleImport::getStdTypeForAttr(Type type) {
if (!type)
return nullptr;
if (type.isa<IntegerType, FloatType>())
return type;
// LLVM vectors can only contain scalars.
if (LLVM::isCompatibleVectorType(type)) {
llvm::ElementCount numElements = LLVM::getVectorNumElements(type);
if (numElements.isScalable()) {
emitError(UnknownLoc::get(context)) << "scalable vectors not supported";
return nullptr;
}
Type elementType = getStdTypeForAttr(LLVM::getVectorElementType(type));
if (!elementType)
return nullptr;
return VectorType::get(numElements.getKnownMinValue(), elementType);
}
// LLVM arrays can contain other arrays or vectors.
if (auto arrayType = type.dyn_cast<LLVMArrayType>()) {
// Recover the nested array shape.
SmallVector<int64_t, 4> shape;
shape.push_back(arrayType.getNumElements());
while (arrayType.getElementType().isa<LLVMArrayType>()) {
arrayType = arrayType.getElementType().cast<LLVMArrayType>();
shape.push_back(arrayType.getNumElements());
}
// If the innermost type is a vector, use the multi-dimensional vector as
// attribute type.
if (LLVM::isCompatibleVectorType(arrayType.getElementType())) {
llvm::ElementCount numElements =
LLVM::getVectorNumElements(arrayType.getElementType());
if (numElements.isScalable()) {
emitError(UnknownLoc::get(context)) << "scalable vectors not supported";
return nullptr;
}
shape.push_back(numElements.getKnownMinValue());
Type elementType = getStdTypeForAttr(
LLVM::getVectorElementType(arrayType.getElementType()));
if (!elementType)
return nullptr;
return VectorType::get(shape, elementType);
}
// Otherwise use a tensor.
Type elementType = getStdTypeForAttr(arrayType.getElementType());
if (!elementType)
return nullptr;
return RankedTensorType::get(shape, elementType);
}
return nullptr;
}
// Get the given constant as an attribute. Not all constants can be represented
// as attributes.
Attribute ModuleImport::getConstantAsAttr(llvm::Constant *value) {
if (auto *ci = dyn_cast<llvm::ConstantInt>(value))
return builder.getIntegerAttr(
IntegerType::get(context, ci->getType()->getBitWidth()),
ci->getValue());
if (auto *c = dyn_cast<llvm::ConstantDataArray>(value))
if (c->isString())
return builder.getStringAttr(c->getAsString());
if (auto *c = dyn_cast<llvm::ConstantFP>(value)) {
llvm::Type *type = c->getType();
FloatType floatTy;
if (type->isBFloatTy())
floatTy = FloatType::getBF16(context);
else
floatTy = getDLFloatType(*context, type->getScalarSizeInBits());
assert(floatTy && "unsupported floating point type");
return builder.getFloatAttr(floatTy, c->getValueAPF());
}
if (auto *f = dyn_cast<llvm::Function>(value))
return SymbolRefAttr::get(builder.getContext(), f->getName());
// Convert constant data to a dense elements attribute.
if (auto *cd = dyn_cast<llvm::ConstantDataSequential>(value)) {
Type type = convertType(cd->getElementType());
auto attrType = getStdTypeForAttr(convertType(cd->getType()))
.dyn_cast_or_null<ShapedType>();
if (!attrType)
return nullptr;
if (type.isa<IntegerType>()) {
SmallVector<APInt, 8> values;
values.reserve(cd->getNumElements());
for (unsigned i = 0, e = cd->getNumElements(); i < e; ++i)
values.push_back(cd->getElementAsAPInt(i));
return DenseElementsAttr::get(attrType, values);
}
if (type.isa<Float32Type, Float64Type>()) {
SmallVector<APFloat, 8> values;
values.reserve(cd->getNumElements());
for (unsigned i = 0, e = cd->getNumElements(); i < e; ++i)
values.push_back(cd->getElementAsAPFloat(i));
return DenseElementsAttr::get(attrType, values);
}
return nullptr;
}
// Unpack constant aggregates to create dense elements attribute whenever
// possible. Return nullptr (failure) otherwise.
if (isa<llvm::ConstantAggregate>(value)) {
auto outerType = getStdTypeForAttr(convertType(value->getType()))
.dyn_cast_or_null<ShapedType>();
if (!outerType)
return nullptr;
SmallVector<Attribute, 8> values;
SmallVector<int64_t, 8> shape;
for (unsigned i = 0, e = value->getNumOperands(); i < e; ++i) {
auto nested = getConstantAsAttr(value->getAggregateElement(i))
.dyn_cast_or_null<DenseElementsAttr>();
if (!nested)
return nullptr;
values.append(nested.value_begin<Attribute>(),
nested.value_end<Attribute>());
}
return DenseElementsAttr::get(outerType, values);
}
return nullptr;
}
GlobalOp ModuleImport::processGlobal(llvm::GlobalVariable *globalVar) {
if (globals.count(globalVar))
return globals[globalVar];
// Insert the global after the last one or at the start of the module.
OpBuilder::InsertionGuard guard(builder);
if (!globalInsertionOp) {
builder.setInsertionPointToStart(mlirModule.getBody());
} else {
builder.setInsertionPointAfter(globalInsertionOp);
}
Attribute valueAttr;
if (globalVar->hasInitializer())
valueAttr = getConstantAsAttr(globalVar->getInitializer());
Type type = convertType(globalVar->getValueType());
uint64_t alignment = 0;
llvm::MaybeAlign maybeAlign = globalVar->getAlign();
if (maybeAlign.has_value()) {
llvm::Align align = *maybeAlign;
alignment = align.value();
}
GlobalOp globalOp = builder.create<GlobalOp>(
UnknownLoc::get(context), type, globalVar->isConstant(),
convertLinkageFromLLVM(globalVar->getLinkage()), globalVar->getName(),
valueAttr, alignment, /*addr_space=*/globalVar->getAddressSpace(),
/*dso_local=*/globalVar->isDSOLocal(),
/*thread_local=*/globalVar->isThreadLocal());
globalInsertionOp = globalOp;
if (globalVar->hasInitializer() && !valueAttr) {
clearBlockAndValueMapping();
Block *block = builder.createBlock(&globalOp.getInitializerRegion());
setConstantInsertionPointToStart(block);
FailureOr<Value> initializer =
convertConstantExpr(globalVar->getInitializer());
if (failed(initializer))
return {};
builder.create<ReturnOp>(globalOp.getLoc(), *initializer);
}
if (globalVar->hasAtLeastLocalUnnamedAddr()) {
globalOp.setUnnamedAddr(
convertUnnamedAddrFromLLVM(globalVar->getUnnamedAddr()));
}
if (globalVar->hasSection())
globalOp.setSection(globalVar->getSection());
return globals[globalVar] = globalOp;
}
SetVector<llvm::Constant *>
ModuleImport::getConstantsToConvert(llvm::Constant *constant) {
// Traverse the constant dependencies in post order.
SmallVector<llvm::Constant *> workList;
SmallVector<llvm::Constant *> orderedList;
workList.push_back(constant);
while (!workList.empty()) {
llvm::Constant *current = workList.pop_back_val();
// Skip constants that have been converted before and store all other ones.
if (valueMapping.count(current))
continue;
orderedList.push_back(current);
// Add the current constant's dependencies to the work list. Only add
// constant dependencies and skip any other values such as basic block
// addresses.
for (llvm::Value *operand : current->operands())
if (auto *constDependency = dyn_cast<llvm::Constant>(operand))
workList.push_back(constDependency);
// Use the `getElementValue` method to add the dependencies of zero
// initialized aggregate constants since they do not take any operands.
if (auto *constAgg = dyn_cast<llvm::ConstantAggregateZero>(current)) {
unsigned numElements = constAgg->getElementCount().getFixedValue();
for (unsigned i = 0, e = numElements; i != e; ++i)
workList.push_back(constAgg->getElementValue(i));
}
}
// Add the constants in reverse post order to the result set to ensure all
// dependencies are satisfied. Avoid storing duplicates since LLVM constants
// are uniqued and only one `valueMapping` entry per constant is possible.
SetVector<llvm::Constant *> orderedSet;
for (llvm::Constant *orderedConst : llvm::reverse(orderedList))
orderedSet.insert(orderedConst);
return orderedSet;
}
FailureOr<Value> ModuleImport::convertConstant(llvm::Constant *constant) {
// Constants have no location attached.
Location loc = UnknownLoc::get(context);
// Convert constants that can be represented as attributes.
if (Attribute attr = getConstantAsAttr(constant)) {
Type type = convertType(constant->getType());
if (auto symbolRef = attr.dyn_cast<FlatSymbolRefAttr>()) {
return builder.create<AddressOfOp>(loc, type, symbolRef.getValue())
.getResult();
}
return builder.create<ConstantOp>(loc, type, attr).getResult();
}
// Convert null pointer constants.
if (auto *nullPtr = dyn_cast<llvm::ConstantPointerNull>(constant)) {
Type type = convertType(nullPtr->getType());
return builder.create<NullOp>(loc, type).getResult();
}
// Convert undef.
if (auto *undefVal = dyn_cast<llvm::UndefValue>(constant)) {
Type type = convertType(undefVal->getType());
return builder.create<UndefOp>(loc, type).getResult();
}
// Convert global variable accesses.
if (auto *globalVar = dyn_cast<llvm::GlobalVariable>(constant)) {
return builder.create<AddressOfOp>(loc, processGlobal(globalVar))
.getResult();
}
// Convert constant expressions.
if (auto *constExpr = dyn_cast<llvm::ConstantExpr>(constant)) {
// Convert the constant expression to a temporary LLVM instruction and
// translate it using the `processInstruction` method. Delete the
// instruction after the translation and remove it from `valueMapping`,
// since later calls to `getAsInstruction` may return the same address
// resulting in a conflicting `valueMapping` entry.
llvm::Instruction *inst = constExpr->getAsInstruction();
auto guard = llvm::make_scope_exit([&]() {
valueMapping.erase(inst);
inst->deleteValue();
});
// Note: `processInstruction` does not call `convertConstant` recursively
// since all constant dependencies have been converted before.
assert(llvm::all_of(inst->operands(), [&](llvm::Value *value) {
return valueMapping.count(value);
}));
if (failed(processInstruction(inst)))
return failure();
return lookupValue(inst);
}
// Convert aggregate constants.
if (isa<llvm::ConstantAggregate>(constant) ||
isa<llvm::ConstantAggregateZero>(constant)) {
// Lookup the aggregate elements that have been converted before.
SmallVector<Value> elementValues;
if (auto *constAgg = dyn_cast<llvm::ConstantAggregate>(constant)) {
elementValues.reserve(constAgg->getNumOperands());
for (llvm::Value *operand : constAgg->operands())
elementValues.push_back(lookupValue(operand));
}
if (auto *constAgg = dyn_cast<llvm::ConstantAggregateZero>(constant)) {
unsigned numElements = constAgg->getElementCount().getFixedValue();
elementValues.reserve(numElements);
for (unsigned i = 0, e = numElements; i != e; ++i)
elementValues.push_back(lookupValue(constAgg->getElementValue(i)));
}
assert(llvm::count(elementValues, nullptr) == 0 &&
"expected all elements have been converted before");
// Generate an UndefOp as root value and insert the aggregate elements.
Type rootType = convertType(constant->getType());
bool isArrayOrStruct = rootType.isa<LLVMArrayType, LLVMStructType>();
assert((isArrayOrStruct || LLVM::isCompatibleVectorType(rootType)) &&
"unrecognized aggregate type");
Value root = builder.create<UndefOp>(loc, rootType);
for (const auto &it : llvm::enumerate(elementValues)) {
if (isArrayOrStruct) {
root = builder.create<InsertValueOp>(loc, root, it.value(), it.index());
} else {
Attribute indexAttr = builder.getI32IntegerAttr(it.index());
Value indexValue =
builder.create<ConstantOp>(loc, builder.getI32Type(), indexAttr);
root = builder.create<InsertElementOp>(loc, rootType, root, it.value(),
indexValue);
}
}
return root;
}
return emitError(loc) << "unhandled constant " << diag(*constant);
}
FailureOr<Value> ModuleImport::convertConstantExpr(llvm::Constant *constant) {
assert(constantInsertionBlock &&
"expected the constant insertion block to be non-null");
// Insert the constant after the last one or at the start or the entry block.
OpBuilder::InsertionGuard guard(builder);
if (!constantInsertionOp) {
builder.setInsertionPointToStart(constantInsertionBlock);
} else {
builder.setInsertionPointAfter(constantInsertionOp);
}
// Convert all constants of the expression and add them to `valueMapping`.
SetVector<llvm::Constant *> constantsToConvert =
getConstantsToConvert(constant);
for (llvm::Constant *constantToConvert : constantsToConvert) {
FailureOr<Value> converted = convertConstant(constantToConvert);
if (failed(converted))
return failure();
mapValue(constantToConvert, *converted);
}
// Update the constant insertion point and return the converted constant.
Value result = lookupValue(constant);
constantInsertionOp = result.getDefiningOp();
return result;
}
FailureOr<Value> ModuleImport::convertValue(llvm::Value *value) {
// A value may be wrapped as metadata, for example, when passed to a debug
// intrinsic. Unwrap these values before the conversion.
if (auto *nodeAsVal = dyn_cast<llvm::MetadataAsValue>(value))
if (auto *node = dyn_cast<llvm::ValueAsMetadata>(nodeAsVal->getMetadata()))
value = node->getValue();
// Return the mapped value if it has been converted before.
if (valueMapping.count(value))
return lookupValue(value);
// Convert constants such as immediate values that have no mapping yet.
if (auto *constant = dyn_cast<llvm::Constant>(value))
return convertConstantExpr(constant);
Location loc = UnknownLoc::get(context);
if (auto *inst = dyn_cast<llvm::Instruction>(value))
loc = translateLoc(inst->getDebugLoc());
return emitError(loc) << "unhandled value " << diag(*value);
}
FailureOr<SmallVector<Value>>
ModuleImport::convertValues(ArrayRef<llvm::Value *> values) {
SmallVector<Value> remapped;
remapped.reserve(values.size());
for (llvm::Value *value : values) {
FailureOr<Value> converted = convertValue(value);
if (failed(converted))
return failure();
remapped.push_back(*converted);
}
return remapped;
}
IntegerAttr ModuleImport::matchIntegerAttr(llvm::Value *value) {
IntegerAttr integerAttr;
FailureOr<Value> converted = convertValue(value);
bool success = succeeded(converted) &&
matchPattern(*converted, m_Constant(&integerAttr));
assert(success && "expected a constant value");
(void)success;
return integerAttr;
}
DILocalVariableAttr ModuleImport::matchLocalVariableAttr(llvm::Value *value) {
auto *nodeAsVal = cast<llvm::MetadataAsValue>(value);
auto *node = cast<llvm::DILocalVariable>(nodeAsVal->getMetadata());
return debugImporter->translate(node);
}
Location ModuleImport::translateLoc(llvm::DILocation *loc) {
return debugImporter->translateLoc(loc);
}
LogicalResult
ModuleImport::convertBranchArgs(llvm::Instruction *branch,
llvm::BasicBlock *target,
SmallVectorImpl<Value> &blockArguments) {
for (auto inst = target->begin(); isa<llvm::PHINode>(inst); ++inst) {
auto *phiInst = cast<llvm::PHINode>(&*inst);
llvm::Value *value = phiInst->getIncomingValueForBlock(branch->getParent());
FailureOr<Value> converted = convertValue(value);
if (failed(converted))
return failure();
blockArguments.push_back(*converted);
}
return success();
}
LogicalResult
ModuleImport::convertCallTypeAndOperands(llvm::CallBase *callInst,
SmallVectorImpl<Type> &types,
SmallVectorImpl<Value> &operands) {
if (!callInst->getType()->isVoidTy())
types.push_back(convertType(callInst->getType()));
if (!callInst->getCalledFunction()) {
FailureOr<Value> called = convertValue(callInst->getCalledOperand());
if (failed(called))
return failure();
operands.push_back(*called);
}
SmallVector<llvm::Value *> args(callInst->args());
FailureOr<SmallVector<Value>> arguments = convertValues(args);
if (failed(arguments))
return failure();
llvm::append_range(operands, *arguments);
return success();
}
LogicalResult ModuleImport::convertIntrinsic(OpBuilder &odsBuilder,
llvm::CallInst *inst) {
if (succeeded(iface.convertIntrinsic(builder, inst, *this)))
return success();
Location loc = translateLoc(inst->getDebugLoc());
return emitError(loc) << "unhandled intrinsic " << diag(*inst);
}
LogicalResult ModuleImport::convertInstruction(OpBuilder &odsBuilder,
llvm::Instruction *inst) {
// Copy the operands to an LLVM operands array reference for conversion.
SmallVector<llvm::Value *> operands(inst->operands());
ArrayRef<llvm::Value *> llvmOperands(operands);
ModuleImport &moduleImport = *this;
// Convert all instructions that provide an MLIR builder.
#include "mlir/Dialect/LLVMIR/LLVMOpFromLLVMIRConversions.inc"
// Convert all remaining instructions that do not provide an MLIR builder.
Location loc = translateLoc(inst->getDebugLoc());
if (inst->getOpcode() == llvm::Instruction::Br) {
auto *brInst = cast<llvm::BranchInst>(inst);
SmallVector<Block *> succBlocks;
SmallVector<SmallVector<Value>> succBlockArgs;
for (auto i : llvm::seq<unsigned>(0, brInst->getNumSuccessors())) {
llvm::BasicBlock *succ = brInst->getSuccessor(i);
SmallVector<Value> blockArgs;
if (failed(convertBranchArgs(brInst, succ, blockArgs)))
return failure();
succBlocks.push_back(lookupBlock(succ));
succBlockArgs.push_back(blockArgs);
}
if (brInst->isConditional()) {
FailureOr<Value> condition = convertValue(brInst->getCondition());
if (failed(condition))
return failure();
builder.create<LLVM::CondBrOp>(loc, *condition, succBlocks.front(),
succBlockArgs.front(), succBlocks.back(),
succBlockArgs.back());
} else {
builder.create<LLVM::BrOp>(loc, succBlockArgs.front(),
succBlocks.front());
}
return success();
}
if (inst->getOpcode() == llvm::Instruction::Switch) {
auto *swInst = cast<llvm::SwitchInst>(inst);
// Process the condition value.
FailureOr<Value> condition = convertValue(swInst->getCondition());
if (failed(condition))
return failure();
SmallVector<Value> defaultBlockArgs;
// Process the default case.
llvm::BasicBlock *defaultBB = swInst->getDefaultDest();
if (failed(convertBranchArgs(swInst, defaultBB, defaultBlockArgs)))
return failure();
// Process the cases.
unsigned numCases = swInst->getNumCases();
SmallVector<SmallVector<Value>> caseOperands(numCases);
SmallVector<ValueRange> caseOperandRefs(numCases);
SmallVector<int32_t> caseValues(numCases);
SmallVector<Block *> caseBlocks(numCases);
for (const auto &it : llvm::enumerate(swInst->cases())) {
const llvm::SwitchInst::CaseHandle &caseHandle = it.value();
llvm::BasicBlock *succBB = caseHandle.getCaseSuccessor();
if (failed(convertBranchArgs(swInst, succBB, caseOperands[it.index()])))
return failure();
caseOperandRefs[it.index()] = caseOperands[it.index()];
caseValues[it.index()] = caseHandle.getCaseValue()->getSExtValue();
caseBlocks[it.index()] = lookupBlock(succBB);
}
builder.create<SwitchOp>(loc, *condition, lookupBlock(defaultBB),
defaultBlockArgs, caseValues, caseBlocks,
caseOperandRefs);
return success();
}
if (inst->getOpcode() == llvm::Instruction::PHI) {
Type type = convertType(inst->getType());
mapValue(inst, builder.getInsertionBlock()->addArgument(
type, translateLoc(inst->getDebugLoc())));
return success();
}
if (inst->getOpcode() == llvm::Instruction::Call) {
auto *callInst = cast<llvm::CallInst>(inst);
SmallVector<Type> types;
SmallVector<Value> operands;
if (failed(convertCallTypeAndOperands(callInst, types, operands)))
return failure();
CallOp callOp;
if (llvm::Function *callee = callInst->getCalledFunction()) {
callOp = builder.create<CallOp>(
loc, types, SymbolRefAttr::get(context, callee->getName()), operands);
} else {
callOp = builder.create<CallOp>(loc, types, operands);
}
setFastmathFlagsAttr(inst, callOp);
if (!callInst->getType()->isVoidTy())
mapValue(inst, callOp.getResult());
return success();
}
if (inst->getOpcode() == llvm::Instruction::LandingPad) {
auto *lpInst = cast<llvm::LandingPadInst>(inst);
SmallVector<Value> operands;
operands.reserve(lpInst->getNumClauses());
for (auto i : llvm::seq<unsigned>(0, lpInst->getNumClauses())) {
FailureOr<Value> operand = convertConstantExpr(lpInst->getClause(i));
if (failed(operand))
return failure();
operands.push_back(*operand);
}
Type type = convertType(lpInst->getType());
Value res =
builder.create<LandingpadOp>(loc, type, lpInst->isCleanup(), operands);
mapValue(inst, res);
return success();
}
if (inst->getOpcode() == llvm::Instruction::Invoke) {
auto *invokeInst = cast<llvm::InvokeInst>(inst);
SmallVector<Type> types;
SmallVector<Value> operands;
if (failed(convertCallTypeAndOperands(invokeInst, types, operands)))
return failure();
SmallVector<Value> normalArgs, unwindArgs;
(void)convertBranchArgs(invokeInst, invokeInst->getNormalDest(),
normalArgs);
(void)convertBranchArgs(invokeInst, invokeInst->getUnwindDest(),
unwindArgs);
InvokeOp invokeOp;
if (llvm::Function *callee = invokeInst->getCalledFunction()) {
invokeOp = builder.create<InvokeOp>(
loc, types,
SymbolRefAttr::get(builder.getContext(), callee->getName()), operands,
lookupBlock(invokeInst->getNormalDest()), normalArgs,
lookupBlock(invokeInst->getUnwindDest()), unwindArgs);
} else {
invokeOp = builder.create<InvokeOp>(
loc, types, operands, lookupBlock(invokeInst->getNormalDest()),
normalArgs, lookupBlock(invokeInst->getUnwindDest()), unwindArgs);
}
if (!invokeInst->getType()->isVoidTy())
mapValue(inst, invokeOp.getResults().front());
return success();
}
if (inst->getOpcode() == llvm::Instruction::GetElementPtr) {
auto *gepInst = cast<llvm::GetElementPtrInst>(inst);
Type sourceElementType = convertType(gepInst->getSourceElementType());
FailureOr<Value> basePtr = convertValue(gepInst->getOperand(0));
if (failed(basePtr))
return failure();
// Treat every indices as dynamic since GEPOp::build will refine those
// indices into static attributes later. One small downside of this
// approach is that many unused `llvm.mlir.constant` would be emitted
// at first place.
SmallVector<GEPArg> indices;
for (llvm::Value *operand : llvm::drop_begin(gepInst->operand_values())) {
FailureOr<Value> index = convertValue(operand);
if (failed(index))
return failure();
indices.push_back(*index);
}
Type type = convertType(inst->getType());
Value res = builder.create<GEPOp>(loc, type, sourceElementType, *basePtr,
indices, gepInst->isInBounds());
mapValue(inst, res);
return success();
}
return emitError(loc) << "unhandled instruction " << diag(*inst);
}
LogicalResult ModuleImport::processInstruction(llvm::Instruction *inst) {
// FIXME: Support uses of SubtargetData.
// FIXME: Add support for call / operand attributes.
// FIXME: Add support for the indirectbr, cleanupret, catchret, catchswitch,
// callbr, vaarg, landingpad, catchpad, cleanuppad instructions.
// Convert LLVM intrinsics calls to MLIR intrinsics.
if (auto *callInst = dyn_cast<llvm::CallInst>(inst)) {
llvm::Function *callee = callInst->getCalledFunction();
if (callee && callee->isIntrinsic())
return convertIntrinsic(builder, callInst);
}
// Convert all remaining LLVM instructions to MLIR operations.
return convertInstruction(builder, inst);
}
FlatSymbolRefAttr ModuleImport::getPersonalityAsAttr(llvm::Function *f) {
if (!f->hasPersonalityFn())
return nullptr;
llvm::Constant *pf = f->getPersonalityFn();
// If it directly has a name, we can use it.
if (pf->hasName())
return SymbolRefAttr::get(builder.getContext(), pf->getName());
// If it doesn't have a name, currently, only function pointers that are
// bitcast to i8* are parsed.
if (auto *ce = dyn_cast<llvm::ConstantExpr>(pf)) {
if (ce->getOpcode() == llvm::Instruction::BitCast &&
ce->getType() == llvm::Type::getInt8PtrTy(f->getContext())) {
if (auto *func = dyn_cast<llvm::Function>(ce->getOperand(0)))
return SymbolRefAttr::get(builder.getContext(), func->getName());
}
}
return FlatSymbolRefAttr();
}
void ModuleImport::processFunctionAttributes(llvm::Function *func,
LLVMFuncOp funcOp) {
auto addNamedUnitAttr = [&](StringRef name) {
return funcOp->setAttr(name, UnitAttr::get(context));
};
if (func->doesNotAccessMemory())
addNamedUnitAttr(LLVMDialect::getReadnoneAttrName());
}
LogicalResult ModuleImport::processFunction(llvm::Function *func) {
clearBlockAndValueMapping();
auto functionType =
convertType(func->getFunctionType()).dyn_cast<LLVMFunctionType>();
if (func->isIntrinsic() &&
iface.isConvertibleIntrinsic(func->getIntrinsicID()))
return success();
bool dsoLocal = func->hasLocalLinkage();
CConv cconv = convertCConvFromLLVM(func->getCallingConv());
// Insert the function at the end of the module.
OpBuilder::InsertionGuard guard(builder);
builder.setInsertionPoint(mlirModule.getBody(), mlirModule.getBody()->end());
LLVMFuncOp funcOp = builder.create<LLVMFuncOp>(
UnknownLoc::get(context), func->getName(), functionType,
convertLinkageFromLLVM(func->getLinkage()), dsoLocal, cconv);
// Set the function debug information if available.
debugImporter->translate(func, funcOp);
for (const auto &it : llvm::enumerate(functionType.getParams())) {
llvm::SmallVector<NamedAttribute, 1> argAttrs;
if (auto *type = func->getParamByValType(it.index())) {
Type mlirType = convertType(type);
argAttrs.push_back(
NamedAttribute(builder.getStringAttr(LLVMDialect::getByValAttrName()),
TypeAttr::get(mlirType)));
}
if (auto *type = func->getParamByRefType(it.index())) {
Type mlirType = convertType(type);
argAttrs.push_back(
NamedAttribute(builder.getStringAttr(LLVMDialect::getByRefAttrName()),
TypeAttr::get(mlirType)));
}
if (auto *type = func->getParamStructRetType(it.index())) {
Type mlirType = convertType(type);
argAttrs.push_back(NamedAttribute(
builder.getStringAttr(LLVMDialect::getStructRetAttrName()),
TypeAttr::get(mlirType)));
}
if (auto *type = func->getParamInAllocaType(it.index())) {
Type mlirType = convertType(type);
argAttrs.push_back(NamedAttribute(
builder.getStringAttr(LLVMDialect::getInAllocaAttrName()),
TypeAttr::get(mlirType)));
}
funcOp.setArgAttrs(it.index(), argAttrs);
}
if (FlatSymbolRefAttr personality = getPersonalityAsAttr(func))
funcOp.setPersonalityAttr(personality);
else if (func->hasPersonalityFn())
emitWarning(UnknownLoc::get(context),
"could not deduce personality, skipping it");
if (func->hasGC())
funcOp.setGarbageCollector(StringRef(func->getGC()));
// Handle Function attributes.
processFunctionAttributes(func, funcOp);
if (func->isDeclaration())
return success();
// Eagerly create all blocks.
for (llvm::BasicBlock &bb : *func) {
Block *block =
builder.createBlock(&funcOp.getBody(), funcOp.getBody().end());
mapBlock(&bb, block);
}
// Add function arguments to the entry block.
for (const auto &it : llvm::enumerate(func->args())) {
BlockArgument blockArg = funcOp.getFunctionBody().addArgument(
functionType.getParamType(it.index()), funcOp.getLoc());
mapValue(&it.value(), blockArg);
}
// Process the blocks in topological order. The ordered traversal ensures
// operands defined in a dominating block have a valid mapping to an MLIR
// value once a block is translated.
SetVector<llvm::BasicBlock *> blocks = getTopologicallySortedBlocks(func);
setConstantInsertionPointToStart(lookupBlock(blocks.front()));
for (llvm::BasicBlock *bb : blocks) {
if (failed(processBasicBlock(bb, lookupBlock(bb))))
return failure();
}
return success();
}
LogicalResult ModuleImport::processBasicBlock(llvm::BasicBlock *bb,
Block *block) {
builder.setInsertionPointToStart(block);
for (llvm::Instruction &inst : *bb) {
if (failed(processInstruction(&inst)))
return failure();
}
return success();
}
OwningOpRef<ModuleOp>
mlir::translateLLVMIRToModule(std::unique_ptr<llvm::Module> llvmModule,
MLIRContext *context) {
// Preload all registered dialects to allow the import to iterate the
// registered LLVMImportDialectInterface implementations and query the
// supported LLVM IR constructs before starting the translation. Assumes the
// LLVM and DLTI dialects that convert the core LLVM IR constructs have been
// registered before.
assert(llvm::is_contained(context->getAvailableDialects(),
LLVMDialect::getDialectNamespace()));
assert(llvm::is_contained(context->getAvailableDialects(),
DLTIDialect::getDialectNamespace()));
context->loadAllAvailableDialects();
OwningOpRef<ModuleOp> module(ModuleOp::create(FileLineColLoc::get(
StringAttr::get(context, llvmModule->getSourceFileName()), /*line=*/0,
/*column=*/0)));
DataLayoutSpecInterface dlSpec =
translateDataLayout(llvmModule->getDataLayout(), context);
if (!dlSpec) {
emitError(UnknownLoc::get(context), "can't translate data layout");
return {};
}
module.get()->setAttr(DLTIDialect::kDataLayoutAttrName, dlSpec);
ModuleImport moduleImport(module.get(), std::move(llvmModule));
if (failed(moduleImport.initializeImportInterface()))
return {};
if (failed(moduleImport.convertGlobals()))
return {};
if (failed(moduleImport.convertFunctions()))
return {};
return module;
}
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