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//===- TestDenseDataFlowAnalysis.cpp - Test dense data flow analysis ------===//
//
// 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 "TestDenseDataFlowAnalysis.h"
#include "TestDialect.h"
#include "mlir/Analysis/DataFlow/ConstantPropagationAnalysis.h"
#include "mlir/Analysis/DataFlow/DeadCodeAnalysis.h"
#include "mlir/Analysis/DataFlow/DenseAnalysis.h"
#include "mlir/Interfaces/SideEffectInterfaces.h"
#include "mlir/Pass/Pass.h"
#include <optional>
using namespace mlir;
using namespace mlir::dataflow;
using namespace mlir::dataflow::test;
namespace {
/// This lattice represents, for a given memory resource, the potential last
/// operations that modified the resource.
class LastModification : public AbstractDenseLattice, public AccessLatticeBase {
public:
MLIR_DEFINE_EXPLICIT_INTERNAL_INLINE_TYPE_ID(LastModification)
using AbstractDenseLattice::AbstractDenseLattice;
/// Join the last modifications.
ChangeResult join(const AbstractDenseLattice &lattice) override {
return AccessLatticeBase::merge(static_cast<AccessLatticeBase>(
static_cast<const LastModification &>(lattice)));
}
void print(raw_ostream &os) const override {
return AccessLatticeBase::print(os);
}
};
class LastModifiedAnalysis : public DenseDataFlowAnalysis<LastModification> {
public:
using DenseDataFlowAnalysis::DenseDataFlowAnalysis;
/// Visit an operation. If the operation has no memory effects, then the state
/// is propagated with no change. If the operation allocates a resource, then
/// its reaching definitions is set to empty. If the operation writes to a
/// resource, then its reaching definition is set to the written value.
void visitOperation(Operation *op, const LastModification &before,
LastModification *after) override;
void visitCallControlFlowTransfer(CallOpInterface call,
CallControlFlowAction action,
const LastModification &before,
LastModification *after) override;
void visitRegionBranchControlFlowTransfer(RegionBranchOpInterface branch,
std::optional<unsigned> regionFrom,
std::optional<unsigned> regionTo,
const LastModification &before,
LastModification *after) override;
/// At an entry point, the last modifications of all memory resources are
/// unknown.
void setToEntryState(LastModification *lattice) override {
propagateIfChanged(lattice, lattice->reset());
}
};
} // end anonymous namespace
void LastModifiedAnalysis::visitOperation(Operation *op,
const LastModification &before,
LastModification *after) {
auto memory = dyn_cast<MemoryEffectOpInterface>(op);
// If we can't reason about the memory effects, then conservatively assume we
// can't deduce anything about the last modifications.
if (!memory)
return setToEntryState(after);
SmallVector<MemoryEffects::EffectInstance> effects;
memory.getEffects(effects);
ChangeResult result = after->join(before);
for (const auto &effect : effects) {
Value value = effect.getValue();
// If we see an effect on anything other than a value, assume we can't
// deduce anything about the last modifications.
if (!value)
return setToEntryState(after);
// If we cannot find the underlying value, we shouldn't just propagate the
// effects through, return the pessimistic state.
value = UnderlyingValueAnalysis::getMostUnderlyingValue(
value, [&](Value value) {
return getOrCreateFor<UnderlyingValueLattice>(op, value);
});
if (!value)
return setToEntryState(after);
// Nothing to do for reads.
if (isa<MemoryEffects::Read>(effect.getEffect()))
continue;
result |= after->set(value, op);
}
propagateIfChanged(after, result);
}
void LastModifiedAnalysis::visitCallControlFlowTransfer(
CallOpInterface call, CallControlFlowAction action,
const LastModification &before, LastModification *after) {
auto testCallAndStore =
dyn_cast<::test::TestCallAndStoreOp>(call.getOperation());
if (testCallAndStore && ((action == CallControlFlowAction::EnterCallee &&
testCallAndStore.getStoreBeforeCall()) ||
(action == CallControlFlowAction::ExitCallee &&
!testCallAndStore.getStoreBeforeCall()))) {
return visitOperation(call, before, after);
}
AbstractDenseDataFlowAnalysis::visitCallControlFlowTransfer(call, action,
before, after);
}
void LastModifiedAnalysis::visitRegionBranchControlFlowTransfer(
RegionBranchOpInterface branch, std::optional<unsigned> regionFrom,
std::optional<unsigned> regionTo, const LastModification &before,
LastModification *after) {
auto testStoreWithARegion =
dyn_cast<::test::TestStoreWithARegion>(branch.getOperation());
if (testStoreWithARegion &&
((!regionTo && !testStoreWithARegion.getStoreBeforeRegion()) ||
(!regionFrom && testStoreWithARegion.getStoreBeforeRegion()))) {
return visitOperation(branch, before, after);
}
AbstractDenseDataFlowAnalysis::visitRegionBranchControlFlowTransfer(
branch, regionFrom, regionTo, before, after);
}
namespace {
struct TestLastModifiedPass
: public PassWrapper<TestLastModifiedPass, OperationPass<>> {
MLIR_DEFINE_EXPLICIT_INTERNAL_INLINE_TYPE_ID(TestLastModifiedPass)
StringRef getArgument() const override { return "test-last-modified"; }
void runOnOperation() override {
Operation *op = getOperation();
DataFlowSolver solver;
solver.load<DeadCodeAnalysis>();
solver.load<SparseConstantPropagation>();
solver.load<LastModifiedAnalysis>();
solver.load<UnderlyingValueAnalysis>();
if (failed(solver.initializeAndRun(op)))
return signalPassFailure();
raw_ostream &os = llvm::errs();
op->walk([&](Operation *op) {
auto tag = op->getAttrOfType<StringAttr>("tag");
if (!tag)
return;
os << "test_tag: " << tag.getValue() << ":\n";
const LastModification *lastMods =
solver.lookupState<LastModification>(op);
assert(lastMods && "expected a dense lattice");
for (auto [index, operand] : llvm::enumerate(op->getOperands())) {
os << " operand #" << index << "\n";
Value value = UnderlyingValueAnalysis::getMostUnderlyingValue(
operand, [&](Value value) {
return solver.lookupState<UnderlyingValueLattice>(value);
});
assert(value && "expected an underlying value");
if (std::optional<ArrayRef<Operation *>> lastMod =
lastMods->getAdjacentAccess(value)) {
for (Operation *lastModifier : *lastMod) {
if (auto tagName =
lastModifier->getAttrOfType<StringAttr>("tag_name")) {
os << " - " << tagName.getValue() << "\n";
} else {
os << " - " << lastModifier->getName() << "\n";
}
}
} else {
os << " - <unknown>\n";
}
}
});
}
};
} // end anonymous namespace
namespace mlir {
namespace test {
void registerTestLastModifiedPass() {
PassRegistration<TestLastModifiedPass>();
}
} // end namespace test
} // end namespace mlir
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