diff options
| -rw-r--r-- | backend/lib/CodeGen/MachineLiveness.cpp | 76 | ||||
| -rw-r--r-- | backend/unittests/CodeGen/MachineLivenessTest.cpp | 30 |
2 files changed, 103 insertions, 3 deletions
diff --git a/backend/lib/CodeGen/MachineLiveness.cpp b/backend/lib/CodeGen/MachineLiveness.cpp index 7984e7d..9882b11 100644 --- a/backend/lib/CodeGen/MachineLiveness.cpp +++ b/backend/lib/CodeGen/MachineLiveness.cpp @@ -900,6 +900,66 @@ liveSetIntersects(const MachineOperand &Operand, const RegisterLaneSet &Virtual, return addOperandUse(Virtual, Physical, Operand, Function, Target); } +[[nodiscard]] Expected<RegisterUnitLaneSet> +requiredLocalPhysicalLiveIns(const MachineBasicBlock &Block, const MachineFunction &Function, + const TargetDescription &Target) { + RegisterLaneSet Virtual; + RegisterUnitLaneSet Physical; + for (const MachineInstr *Instruction = Block.lastInstruction(); Instruction != nullptr; + Instruction = Instruction->previous()) { + const InstructionDescriptor *Descriptor = Target.instructionDescriptor(Instruction->opcode()); + if (Descriptor == nullptr) { + return makeUnexpected(ErrorCode::VerificationError, + "liveness verification encountered an unknown instruction descriptor"); + } + const bool IsPhi = Descriptor->Flags.has(InstructionFlag::Phi); + for (const MachineOperand &Operand : Instruction->operands()) { + const auto *MaskOperand = Operand.getIf<LiveOutRegisterMaskOperand>(); + if (MaskOperand == nullptr) + continue; + if (!MaskOperand->Mask) { + return makeUnexpected(ErrorCode::VerificationError, + "liveness verification encountered a null live-out register mask"); + } + auto Added = addRegisterMaskUses(Physical, *MaskOperand->Mask, Target); + if (!Added) + return std::unexpected(Added.error()); + } + + for (const MachineOperand &Operand : Instruction->operands()) { + if (Operand.isRegister() && Operand.isDef()) { + auto Removed = removeOperandFromLiveSet(Operand, Virtual, Physical, Function, Target); + if (!Removed) + return std::unexpected(Removed.error()); + continue; + } + const auto *MaskOperand = Operand.getIf<RegisterMaskOperand>(); + if (MaskOperand == nullptr) + continue; + if (!MaskOperand->Mask) { + return makeUnexpected(ErrorCode::VerificationError, + "liveness verification encountered a null register mask"); + } + RegisterUnitLaneSet Clobbers; + auto Added = addRegisterMaskDefs(Clobbers, *MaskOperand->Mask, Target); + if (!Added) + return std::unexpected(Added.error()); + Physical.subtract(Clobbers); + } + + if (IsPhi) + continue; + for (const MachineOperand &Operand : Instruction->operands()) { + if (!Operand.isRegister() || !Operand.isUse()) + continue; + auto Added = addOperandToLiveSet(Operand, Virtual, Physical, Function, Target); + if (!Added) + return std::unexpected(Added.error()); + } + } + return Physical; +} + [[nodiscard]] Expected<LivenessRebuildPlan> buildLivenessRebuildPlan(const MachineFunction &Function, const TargetDescription &Target) { auto Variables = computeLiveVariables(Function, Target); @@ -1792,14 +1852,24 @@ Expected<void> verifyTrackedMachineLiveness(const MachineFunction &Function, auto Plan = buildLivenessRebuildPlan(Function, Target); if (!Plan) return std::unexpected(Plan.error()); - for (const BlockLivenessPlan &BlockPlan : Plan->Blocks) { - auto Actual = liveInUnits(BlockPlan.OriginalLiveIns, Target); + for (const MachineBasicBlock *Block = Function.firstBlock(); Block != nullptr; + Block = Block->next()) { + auto Actual = liveInUnits(Block->liveIns(), Target); if (!Actual) return std::unexpected(Actual.error()); - auto Expected = liveInUnits(BlockPlan.RebuiltLiveIns, Target); + auto Expected = requiredLocalPhysicalLiveIns(*Block, Function, Target); if (!Expected) return std::unexpected(Expected.error()); if (!isSubset(*Expected, *Actual)) { + const auto Missing = std::ranges::find_if(Expected->entries(), [&Actual](const auto &Entry) { + return !Actual->contains(Entry.first, Entry.second); + }); + if (Missing != Expected->entries().end()) { + return makeUnexpected(ErrorCode::VerificationError, + "TracksLiveness block " + std::to_string(Block->stableID().value()) + + " is missing required physical register unit " + + std::to_string(Missing->first.value())); + } return makeUnexpected(ErrorCode::VerificationError, "TracksLiveness block is missing required physical live-ins"); } diff --git a/backend/unittests/CodeGen/MachineLivenessTest.cpp b/backend/unittests/CodeGen/MachineLivenessTest.cpp index cca7629..50e6ffc 100644 --- a/backend/unittests/CodeGen/MachineLivenessTest.cpp +++ b/backend/unittests/CodeGen/MachineLivenessTest.cpp @@ -685,6 +685,35 @@ void testLivenessRebuildAndVerifier(TestContext &Context, const rcc::TargetDescr "a second liveness rebuild must repair stale derived state"); } +void testTrackedLiveThroughPhysicalRegister(TestContext &Context, + const rcc::TargetDescription &Target) { + auto Fixture = createFunction("tracked-live-through", 11, 2); + if (!Fixture) { + Context.expect(false, "tracked live-through fixture creation must succeed"); + return; + } + auto &Function = *Fixture->Function; + auto &Predecessor = *Fixture->Blocks[0]; + auto &Successor = *Fixture->Blocks[1]; + const rcc::Register G0 = rcc::Register::fromPhysical(physical(rcc::test::TestRegister::G0)); + auto Edge = + Function.cfgUpdater().addSuccessor(Predecessor, Successor, rcc::BranchProbability::one()); + auto Use = buildUse(Function, Target, Successor, G0); + auto LiveIn = Successor.addLiveIn(physical(rcc::test::TestRegister::G0)); + if (!Edge || !Use || !LiveIn) { + Context.expect(false, "tracked live-through MachineIR must be constructed"); + return; + } + + Function.properties().set(rcc::MachineFunctionProperty::TracksLiveness); + Context.expect(rcc::verifyTrackedMachineLiveness(Function, Target).has_value() && + Predecessor.liveIns().empty(), + "a predecessor must not declare a physical register used only by its successor"); + Successor.clearLiveIns(); + Context.expect(!rcc::verifyTrackedMachineLiveness(Function, Target), + "a block must declare a physical register that it reads before defining"); +} + void testFailedRebuildIsAtomic(TestContext &Context, const rcc::TargetDescription &Target) { auto Fixture = createFunction("failed-rebuild", 9, 2); if (!Fixture) { @@ -933,6 +962,7 @@ int main() { testLaneSubrangesAndEarlyClobber(Context, *Target); testPhysicalUnitsAndRegMasks(Context, *Target); testLivenessRebuildAndVerifier(Context, *Target); + testTrackedLiveThroughPhysicalRegister(Context, *Target); testFailedRebuildIsAtomic(Context, *Target); testAnalysisRegistrationAndInvalidation(Context, *Target); testRISCVLiveness(Context); |