| //=- WebAssemblyISelLowering.cpp - WebAssembly DAG Lowering Implementation -==// |
| // |
| // 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 |
| // |
| //===----------------------------------------------------------------------===// |
| /// |
| /// \file |
| /// This file implements the WebAssemblyTargetLowering class. |
| /// |
| //===----------------------------------------------------------------------===// |
| |
| #include "WebAssemblyISelLowering.h" |
| #include "MCTargetDesc/WebAssemblyMCTargetDesc.h" |
| #include "WebAssemblyMachineFunctionInfo.h" |
| #include "WebAssemblySubtarget.h" |
| #include "WebAssemblyTargetMachine.h" |
| #include "llvm/CodeGen/Analysis.h" |
| #include "llvm/CodeGen/CallingConvLower.h" |
| #include "llvm/CodeGen/MachineInstrBuilder.h" |
| #include "llvm/CodeGen/MachineJumpTableInfo.h" |
| #include "llvm/CodeGen/MachineModuleInfo.h" |
| #include "llvm/CodeGen/MachineRegisterInfo.h" |
| #include "llvm/CodeGen/SelectionDAG.h" |
| #include "llvm/CodeGen/WasmEHFuncInfo.h" |
| #include "llvm/IR/DiagnosticInfo.h" |
| #include "llvm/IR/DiagnosticPrinter.h" |
| #include "llvm/IR/Function.h" |
| #include "llvm/IR/Intrinsics.h" |
| #include "llvm/Support/Debug.h" |
| #include "llvm/Support/ErrorHandling.h" |
| #include "llvm/Support/raw_ostream.h" |
| #include "llvm/Target/TargetOptions.h" |
| using namespace llvm; |
| |
| #define DEBUG_TYPE "wasm-lower" |
| |
| WebAssemblyTargetLowering::WebAssemblyTargetLowering( |
| const TargetMachine &TM, const WebAssemblySubtarget &STI) |
| : TargetLowering(TM), Subtarget(&STI) { |
| auto MVTPtr = Subtarget->hasAddr64() ? MVT::i64 : MVT::i32; |
| |
| // Booleans always contain 0 or 1. |
| setBooleanContents(ZeroOrOneBooleanContent); |
| // Except in SIMD vectors |
| setBooleanVectorContents(ZeroOrNegativeOneBooleanContent); |
| // WebAssembly does not produce floating-point exceptions on normal floating |
| // point operations. |
| setHasFloatingPointExceptions(false); |
| // We don't know the microarchitecture here, so just reduce register pressure. |
| setSchedulingPreference(Sched::RegPressure); |
| // Tell ISel that we have a stack pointer. |
| setStackPointerRegisterToSaveRestore( |
| Subtarget->hasAddr64() ? WebAssembly::SP64 : WebAssembly::SP32); |
| // Set up the register classes. |
| addRegisterClass(MVT::i32, &WebAssembly::I32RegClass); |
| addRegisterClass(MVT::i64, &WebAssembly::I64RegClass); |
| addRegisterClass(MVT::f32, &WebAssembly::F32RegClass); |
| addRegisterClass(MVT::f64, &WebAssembly::F64RegClass); |
| if (Subtarget->hasSIMD128()) { |
| addRegisterClass(MVT::v16i8, &WebAssembly::V128RegClass); |
| addRegisterClass(MVT::v8i16, &WebAssembly::V128RegClass); |
| addRegisterClass(MVT::v4i32, &WebAssembly::V128RegClass); |
| addRegisterClass(MVT::v4f32, &WebAssembly::V128RegClass); |
| } |
| if (Subtarget->hasUnimplementedSIMD128()) { |
| addRegisterClass(MVT::v2i64, &WebAssembly::V128RegClass); |
| addRegisterClass(MVT::v2f64, &WebAssembly::V128RegClass); |
| } |
| // Compute derived properties from the register classes. |
| computeRegisterProperties(Subtarget->getRegisterInfo()); |
| |
| setOperationAction(ISD::GlobalAddress, MVTPtr, Custom); |
| setOperationAction(ISD::ExternalSymbol, MVTPtr, Custom); |
| setOperationAction(ISD::JumpTable, MVTPtr, Custom); |
| setOperationAction(ISD::BlockAddress, MVTPtr, Custom); |
| setOperationAction(ISD::BRIND, MVT::Other, Custom); |
| |
| // Take the default expansion for va_arg, va_copy, and va_end. There is no |
| // default action for va_start, so we do that custom. |
| setOperationAction(ISD::VASTART, MVT::Other, Custom); |
| setOperationAction(ISD::VAARG, MVT::Other, Expand); |
| setOperationAction(ISD::VACOPY, MVT::Other, Expand); |
| setOperationAction(ISD::VAEND, MVT::Other, Expand); |
| |
| for (auto T : {MVT::f32, MVT::f64, MVT::v4f32, MVT::v2f64}) { |
| // Don't expand the floating-point types to constant pools. |
| setOperationAction(ISD::ConstantFP, T, Legal); |
| // Expand floating-point comparisons. |
| for (auto CC : {ISD::SETO, ISD::SETUO, ISD::SETUEQ, ISD::SETONE, |
| ISD::SETULT, ISD::SETULE, ISD::SETUGT, ISD::SETUGE}) |
| setCondCodeAction(CC, T, Expand); |
| // Expand floating-point library function operators. |
| for (auto Op : |
| {ISD::FSIN, ISD::FCOS, ISD::FSINCOS, ISD::FPOW, ISD::FREM, ISD::FMA}) |
| setOperationAction(Op, T, Expand); |
| // Note supported floating-point library function operators that otherwise |
| // default to expand. |
| for (auto Op : |
| {ISD::FCEIL, ISD::FFLOOR, ISD::FTRUNC, ISD::FNEARBYINT, ISD::FRINT}) |
| setOperationAction(Op, T, Legal); |
| // Support minimum and maximum, which otherwise default to expand. |
| setOperationAction(ISD::FMINIMUM, T, Legal); |
| setOperationAction(ISD::FMAXIMUM, T, Legal); |
| // WebAssembly currently has no builtin f16 support. |
| setOperationAction(ISD::FP16_TO_FP, T, Expand); |
| setOperationAction(ISD::FP_TO_FP16, T, Expand); |
| setLoadExtAction(ISD::EXTLOAD, T, MVT::f16, Expand); |
| setTruncStoreAction(T, MVT::f16, Expand); |
| } |
| |
| // Expand unavailable integer operations. |
| for (auto Op : |
| {ISD::BSWAP, ISD::SMUL_LOHI, ISD::UMUL_LOHI, ISD::MULHS, ISD::MULHU, |
| ISD::SDIVREM, ISD::UDIVREM, ISD::SHL_PARTS, ISD::SRA_PARTS, |
| ISD::SRL_PARTS, ISD::ADDC, ISD::ADDE, ISD::SUBC, ISD::SUBE}) { |
| for (auto T : {MVT::i32, MVT::i64}) |
| setOperationAction(Op, T, Expand); |
| if (Subtarget->hasSIMD128()) |
| for (auto T : {MVT::v16i8, MVT::v8i16, MVT::v4i32}) |
| setOperationAction(Op, T, Expand); |
| if (Subtarget->hasUnimplementedSIMD128()) |
| setOperationAction(Op, MVT::v2i64, Expand); |
| } |
| |
| // SIMD-specific configuration |
| if (Subtarget->hasSIMD128()) { |
| // Support saturating add for i8x16 and i16x8 |
| for (auto Op : {ISD::SADDSAT, ISD::UADDSAT}) |
| for (auto T : {MVT::v16i8, MVT::v8i16}) |
| setOperationAction(Op, T, Legal); |
| |
| // Custom lower BUILD_VECTORs to minimize number of replace_lanes |
| for (auto T : {MVT::v16i8, MVT::v8i16, MVT::v4i32, MVT::v4f32}) |
| setOperationAction(ISD::BUILD_VECTOR, T, Custom); |
| if (Subtarget->hasUnimplementedSIMD128()) |
| for (auto T : {MVT::v2i64, MVT::v2f64}) |
| setOperationAction(ISD::BUILD_VECTOR, T, Custom); |
| |
| // We have custom shuffle lowering to expose the shuffle mask |
| for (auto T : {MVT::v16i8, MVT::v8i16, MVT::v4i32, MVT::v4f32}) |
| setOperationAction(ISD::VECTOR_SHUFFLE, T, Custom); |
| if (Subtarget->hasUnimplementedSIMD128()) |
| for (auto T: {MVT::v2i64, MVT::v2f64}) |
| setOperationAction(ISD::VECTOR_SHUFFLE, T, Custom); |
| |
| // Custom lowering since wasm shifts must have a scalar shift amount |
| for (auto Op : {ISD::SHL, ISD::SRA, ISD::SRL}) { |
| for (auto T : {MVT::v16i8, MVT::v8i16, MVT::v4i32}) |
| setOperationAction(Op, T, Custom); |
| if (Subtarget->hasUnimplementedSIMD128()) |
| setOperationAction(Op, MVT::v2i64, Custom); |
| } |
| |
| // Custom lower lane accesses to expand out variable indices |
| for (auto Op : {ISD::EXTRACT_VECTOR_ELT, ISD::INSERT_VECTOR_ELT}) { |
| for (auto T : {MVT::v16i8, MVT::v8i16, MVT::v4i32, MVT::v4f32}) |
| setOperationAction(Op, T, Custom); |
| if (Subtarget->hasUnimplementedSIMD128()) |
| for (auto T : {MVT::v2i64, MVT::v2f64}) |
| setOperationAction(Op, T, Custom); |
| } |
| |
| // There is no i64x2.mul instruction |
| setOperationAction(ISD::MUL, MVT::v2i64, Expand); |
| |
| // There are no vector select instructions |
| for (auto Op : {ISD::VSELECT, ISD::SELECT_CC, ISD::SELECT}) { |
| for (auto T : {MVT::v16i8, MVT::v8i16, MVT::v4i32, MVT::v4f32}) |
| setOperationAction(Op, T, Expand); |
| if (Subtarget->hasUnimplementedSIMD128()) |
| for (auto T : {MVT::v2i64, MVT::v2f64}) |
| setOperationAction(Op, T, Expand); |
| } |
| |
| // Expand additional SIMD ops that V8 hasn't implemented yet |
| if (!Subtarget->hasUnimplementedSIMD128()) { |
| setOperationAction(ISD::FSQRT, MVT::v4f32, Expand); |
| setOperationAction(ISD::FDIV, MVT::v4f32, Expand); |
| } |
| } |
| |
| // As a special case, these operators use the type to mean the type to |
| // sign-extend from. |
| setOperationAction(ISD::SIGN_EXTEND_INREG, MVT::i1, Expand); |
| if (!Subtarget->hasSignExt()) { |
| // Sign extends are legal only when extending a vector extract |
| auto Action = Subtarget->hasSIMD128() ? Custom : Expand; |
| for (auto T : {MVT::i8, MVT::i16, MVT::i32}) |
| setOperationAction(ISD::SIGN_EXTEND_INREG, T, Action); |
| } |
| for (auto T : MVT::integer_vector_valuetypes()) |
| setOperationAction(ISD::SIGN_EXTEND_INREG, T, Expand); |
| |
| // Dynamic stack allocation: use the default expansion. |
| setOperationAction(ISD::STACKSAVE, MVT::Other, Expand); |
| setOperationAction(ISD::STACKRESTORE, MVT::Other, Expand); |
| setOperationAction(ISD::DYNAMIC_STACKALLOC, MVTPtr, Expand); |
| |
| setOperationAction(ISD::FrameIndex, MVT::i32, Custom); |
| setOperationAction(ISD::CopyToReg, MVT::Other, Custom); |
| |
| // Expand these forms; we pattern-match the forms that we can handle in isel. |
| for (auto T : {MVT::i32, MVT::i64, MVT::f32, MVT::f64}) |
| for (auto Op : {ISD::BR_CC, ISD::SELECT_CC}) |
| setOperationAction(Op, T, Expand); |
| |
| // We have custom switch handling. |
| setOperationAction(ISD::BR_JT, MVT::Other, Custom); |
| |
| // WebAssembly doesn't have: |
| // - Floating-point extending loads. |
| // - Floating-point truncating stores. |
| // - i1 extending loads. |
| // - extending/truncating SIMD loads/stores |
| setLoadExtAction(ISD::EXTLOAD, MVT::f64, MVT::f32, Expand); |
| setTruncStoreAction(MVT::f64, MVT::f32, Expand); |
| for (auto T : MVT::integer_valuetypes()) |
| for (auto Ext : {ISD::EXTLOAD, ISD::ZEXTLOAD, ISD::SEXTLOAD}) |
| setLoadExtAction(Ext, T, MVT::i1, Promote); |
| if (Subtarget->hasSIMD128()) { |
| for (auto T : {MVT::v16i8, MVT::v8i16, MVT::v4i32, MVT::v2i64, MVT::v4f32, |
| MVT::v2f64}) { |
| for (auto MemT : MVT::vector_valuetypes()) { |
| if (MVT(T) != MemT) { |
| setTruncStoreAction(T, MemT, Expand); |
| for (auto Ext : {ISD::EXTLOAD, ISD::ZEXTLOAD, ISD::SEXTLOAD}) |
| setLoadExtAction(Ext, T, MemT, Expand); |
| } |
| } |
| } |
| } |
| |
| // Don't do anything clever with build_pairs |
| setOperationAction(ISD::BUILD_PAIR, MVT::i64, Expand); |
| |
| // Trap lowers to wasm unreachable |
| setOperationAction(ISD::TRAP, MVT::Other, Legal); |
| |
| // Exception handling intrinsics |
| setOperationAction(ISD::INTRINSIC_WO_CHAIN, MVT::Other, Custom); |
| setOperationAction(ISD::INTRINSIC_VOID, MVT::Other, Custom); |
| |
| setMaxAtomicSizeInBitsSupported(64); |
| |
| if (Subtarget->hasBulkMemory()) { |
| // Using memory.copy is always better than using multiple loads and stores |
| MaxStoresPerMemcpy = 1; |
| MaxStoresPerMemcpyOptSize = 1; |
| MaxStoresPerMemmove = 1; |
| MaxStoresPerMemmoveOptSize = 1; |
| } |
| } |
| |
| TargetLowering::AtomicExpansionKind |
| WebAssemblyTargetLowering::shouldExpandAtomicRMWInIR(AtomicRMWInst *AI) const { |
| // We have wasm instructions for these |
| switch (AI->getOperation()) { |
| case AtomicRMWInst::Add: |
| case AtomicRMWInst::Sub: |
| case AtomicRMWInst::And: |
| case AtomicRMWInst::Or: |
| case AtomicRMWInst::Xor: |
| case AtomicRMWInst::Xchg: |
| return AtomicExpansionKind::None; |
| default: |
| break; |
| } |
| return AtomicExpansionKind::CmpXChg; |
| } |
| |
| FastISel *WebAssemblyTargetLowering::createFastISel( |
| FunctionLoweringInfo &FuncInfo, const TargetLibraryInfo *LibInfo) const { |
| return WebAssembly::createFastISel(FuncInfo, LibInfo); |
| } |
| |
| bool WebAssemblyTargetLowering::isOffsetFoldingLegal( |
| const GlobalAddressSDNode * /*GA*/) const { |
| // All offsets can be folded. |
| return true; |
| } |
| |
| MVT WebAssemblyTargetLowering::getScalarShiftAmountTy(const DataLayout & /*DL*/, |
| EVT VT) const { |
| unsigned BitWidth = NextPowerOf2(VT.getSizeInBits() - 1); |
| if (BitWidth > 1 && BitWidth < 8) |
| BitWidth = 8; |
| |
| if (BitWidth > 64) { |
| // The shift will be lowered to a libcall, and compiler-rt libcalls expect |
| // the count to be an i32. |
| BitWidth = 32; |
| assert(BitWidth >= Log2_32_Ceil(VT.getSizeInBits()) && |
| "32-bit shift counts ought to be enough for anyone"); |
| } |
| |
| MVT Result = MVT::getIntegerVT(BitWidth); |
| assert(Result != MVT::INVALID_SIMPLE_VALUE_TYPE && |
| "Unable to represent scalar shift amount type"); |
| return Result; |
| } |
| |
| // Lower an fp-to-int conversion operator from the LLVM opcode, which has an |
| // undefined result on invalid/overflow, to the WebAssembly opcode, which |
| // traps on invalid/overflow. |
| static MachineBasicBlock *LowerFPToInt(MachineInstr &MI, DebugLoc DL, |
| MachineBasicBlock *BB, |
| const TargetInstrInfo &TII, |
| bool IsUnsigned, bool Int64, |
| bool Float64, unsigned LoweredOpcode) { |
| MachineRegisterInfo &MRI = BB->getParent()->getRegInfo(); |
| |
| unsigned OutReg = MI.getOperand(0).getReg(); |
| unsigned InReg = MI.getOperand(1).getReg(); |
| |
| unsigned Abs = Float64 ? WebAssembly::ABS_F64 : WebAssembly::ABS_F32; |
| unsigned FConst = Float64 ? WebAssembly::CONST_F64 : WebAssembly::CONST_F32; |
| unsigned LT = Float64 ? WebAssembly::LT_F64 : WebAssembly::LT_F32; |
| unsigned GE = Float64 ? WebAssembly::GE_F64 : WebAssembly::GE_F32; |
| unsigned IConst = Int64 ? WebAssembly::CONST_I64 : WebAssembly::CONST_I32; |
| unsigned Eqz = WebAssembly::EQZ_I32; |
| unsigned And = WebAssembly::AND_I32; |
| int64_t Limit = Int64 ? INT64_MIN : INT32_MIN; |
| int64_t Substitute = IsUnsigned ? 0 : Limit; |
| double CmpVal = IsUnsigned ? -(double)Limit * 2.0 : -(double)Limit; |
| auto &Context = BB->getParent()->getFunction().getContext(); |
| Type *Ty = Float64 ? Type::getDoubleTy(Context) : Type::getFloatTy(Context); |
| |
| const BasicBlock *LLVMBB = BB->getBasicBlock(); |
| MachineFunction *F = BB->getParent(); |
| MachineBasicBlock *TrueMBB = F->CreateMachineBasicBlock(LLVMBB); |
| MachineBasicBlock *FalseMBB = F->CreateMachineBasicBlock(LLVMBB); |
| MachineBasicBlock *DoneMBB = F->CreateMachineBasicBlock(LLVMBB); |
| |
| MachineFunction::iterator It = ++BB->getIterator(); |
| F->insert(It, FalseMBB); |
| F->insert(It, TrueMBB); |
| F->insert(It, DoneMBB); |
| |
| // Transfer the remainder of BB and its successor edges to DoneMBB. |
| DoneMBB->splice(DoneMBB->begin(), BB, |
| std::next(MachineBasicBlock::iterator(MI)), BB->end()); |
| DoneMBB->transferSuccessorsAndUpdatePHIs(BB); |
| |
| BB->addSuccessor(TrueMBB); |
| BB->addSuccessor(FalseMBB); |
| TrueMBB->addSuccessor(DoneMBB); |
| FalseMBB->addSuccessor(DoneMBB); |
| |
| unsigned Tmp0, Tmp1, CmpReg, EqzReg, FalseReg, TrueReg; |
| Tmp0 = MRI.createVirtualRegister(MRI.getRegClass(InReg)); |
| Tmp1 = MRI.createVirtualRegister(MRI.getRegClass(InReg)); |
| CmpReg = MRI.createVirtualRegister(&WebAssembly::I32RegClass); |
| EqzReg = MRI.createVirtualRegister(&WebAssembly::I32RegClass); |
| FalseReg = MRI.createVirtualRegister(MRI.getRegClass(OutReg)); |
| TrueReg = MRI.createVirtualRegister(MRI.getRegClass(OutReg)); |
| |
| MI.eraseFromParent(); |
| // For signed numbers, we can do a single comparison to determine whether |
| // fabs(x) is within range. |
| if (IsUnsigned) { |
| Tmp0 = InReg; |
| } else { |
| BuildMI(BB, DL, TII.get(Abs), Tmp0).addReg(InReg); |
| } |
| BuildMI(BB, DL, TII.get(FConst), Tmp1) |
| .addFPImm(cast<ConstantFP>(ConstantFP::get(Ty, CmpVal))); |
| BuildMI(BB, DL, TII.get(LT), CmpReg).addReg(Tmp0).addReg(Tmp1); |
| |
| // For unsigned numbers, we have to do a separate comparison with zero. |
| if (IsUnsigned) { |
| Tmp1 = MRI.createVirtualRegister(MRI.getRegClass(InReg)); |
| unsigned SecondCmpReg = |
| MRI.createVirtualRegister(&WebAssembly::I32RegClass); |
| unsigned AndReg = MRI.createVirtualRegister(&WebAssembly::I32RegClass); |
| BuildMI(BB, DL, TII.get(FConst), Tmp1) |
| .addFPImm(cast<ConstantFP>(ConstantFP::get(Ty, 0.0))); |
| BuildMI(BB, DL, TII.get(GE), SecondCmpReg).addReg(Tmp0).addReg(Tmp1); |
| BuildMI(BB, DL, TII.get(And), AndReg).addReg(CmpReg).addReg(SecondCmpReg); |
| CmpReg = AndReg; |
| } |
| |
| BuildMI(BB, DL, TII.get(Eqz), EqzReg).addReg(CmpReg); |
| |
| // Create the CFG diamond to select between doing the conversion or using |
| // the substitute value. |
| BuildMI(BB, DL, TII.get(WebAssembly::BR_IF)).addMBB(TrueMBB).addReg(EqzReg); |
| BuildMI(FalseMBB, DL, TII.get(LoweredOpcode), FalseReg).addReg(InReg); |
| BuildMI(FalseMBB, DL, TII.get(WebAssembly::BR)).addMBB(DoneMBB); |
| BuildMI(TrueMBB, DL, TII.get(IConst), TrueReg).addImm(Substitute); |
| BuildMI(*DoneMBB, DoneMBB->begin(), DL, TII.get(TargetOpcode::PHI), OutReg) |
| .addReg(FalseReg) |
| .addMBB(FalseMBB) |
| .addReg(TrueReg) |
| .addMBB(TrueMBB); |
| |
| return DoneMBB; |
| } |
| |
| MachineBasicBlock *WebAssemblyTargetLowering::EmitInstrWithCustomInserter( |
| MachineInstr &MI, MachineBasicBlock *BB) const { |
| const TargetInstrInfo &TII = *Subtarget->getInstrInfo(); |
| DebugLoc DL = MI.getDebugLoc(); |
| |
| switch (MI.getOpcode()) { |
| default: |
| llvm_unreachable("Unexpected instr type to insert"); |
| case WebAssembly::FP_TO_SINT_I32_F32: |
| return LowerFPToInt(MI, DL, BB, TII, false, false, false, |
| WebAssembly::I32_TRUNC_S_F32); |
| case WebAssembly::FP_TO_UINT_I32_F32: |
| return LowerFPToInt(MI, DL, BB, TII, true, false, false, |
| WebAssembly::I32_TRUNC_U_F32); |
| case WebAssembly::FP_TO_SINT_I64_F32: |
| return LowerFPToInt(MI, DL, BB, TII, false, true, false, |
| WebAssembly::I64_TRUNC_S_F32); |
| case WebAssembly::FP_TO_UINT_I64_F32: |
| return LowerFPToInt(MI, DL, BB, TII, true, true, false, |
| WebAssembly::I64_TRUNC_U_F32); |
| case WebAssembly::FP_TO_SINT_I32_F64: |
| return LowerFPToInt(MI, DL, BB, TII, false, false, true, |
| WebAssembly::I32_TRUNC_S_F64); |
| case WebAssembly::FP_TO_UINT_I32_F64: |
| return LowerFPToInt(MI, DL, BB, TII, true, false, true, |
| WebAssembly::I32_TRUNC_U_F64); |
| case WebAssembly::FP_TO_SINT_I64_F64: |
| return LowerFPToInt(MI, DL, BB, TII, false, true, true, |
| WebAssembly::I64_TRUNC_S_F64); |
| case WebAssembly::FP_TO_UINT_I64_F64: |
| return LowerFPToInt(MI, DL, BB, TII, true, true, true, |
| WebAssembly::I64_TRUNC_U_F64); |
| llvm_unreachable("Unexpected instruction to emit with custom inserter"); |
| } |
| } |
| |
| const char * |
| WebAssemblyTargetLowering::getTargetNodeName(unsigned Opcode) const { |
| switch (static_cast<WebAssemblyISD::NodeType>(Opcode)) { |
| case WebAssemblyISD::FIRST_NUMBER: |
| break; |
| #define HANDLE_NODETYPE(NODE) \ |
| case WebAssemblyISD::NODE: \ |
| return "WebAssemblyISD::" #NODE; |
| #include "WebAssemblyISD.def" |
| #undef HANDLE_NODETYPE |
| } |
| return nullptr; |
| } |
| |
| std::pair<unsigned, const TargetRegisterClass *> |
| WebAssemblyTargetLowering::getRegForInlineAsmConstraint( |
| const TargetRegisterInfo *TRI, StringRef Constraint, MVT VT) const { |
| // First, see if this is a constraint that directly corresponds to a |
| // WebAssembly register class. |
| if (Constraint.size() == 1) { |
| switch (Constraint[0]) { |
| case 'r': |
| assert(VT != MVT::iPTR && "Pointer MVT not expected here"); |
| if (Subtarget->hasSIMD128() && VT.isVector()) { |
| if (VT.getSizeInBits() == 128) |
| return std::make_pair(0U, &WebAssembly::V128RegClass); |
| } |
| if (VT.isInteger() && !VT.isVector()) { |
| if (VT.getSizeInBits() <= 32) |
| return std::make_pair(0U, &WebAssembly::I32RegClass); |
| if (VT.getSizeInBits() <= 64) |
| return std::make_pair(0U, &WebAssembly::I64RegClass); |
| } |
| break; |
| default: |
| break; |
| } |
| } |
| |
| return TargetLowering::getRegForInlineAsmConstraint(TRI, Constraint, VT); |
| } |
| |
| bool WebAssemblyTargetLowering::isCheapToSpeculateCttz() const { |
| // Assume ctz is a relatively cheap operation. |
| return true; |
| } |
| |
| bool WebAssemblyTargetLowering::isCheapToSpeculateCtlz() const { |
| // Assume clz is a relatively cheap operation. |
| return true; |
| } |
| |
| bool WebAssemblyTargetLowering::isLegalAddressingMode(const DataLayout &DL, |
| const AddrMode &AM, |
| Type *Ty, unsigned AS, |
| Instruction *I) const { |
| // WebAssembly offsets are added as unsigned without wrapping. The |
| // isLegalAddressingMode gives us no way to determine if wrapping could be |
| // happening, so we approximate this by accepting only non-negative offsets. |
| if (AM.BaseOffs < 0) |
| return false; |
| |
| // WebAssembly has no scale register operands. |
| if (AM.Scale != 0) |
| return false; |
| |
| // Everything else is legal. |
| return true; |
| } |
| |
| bool WebAssemblyTargetLowering::allowsMisalignedMemoryAccesses( |
| EVT /*VT*/, unsigned /*AddrSpace*/, unsigned /*Align*/, bool *Fast) const { |
| // WebAssembly supports unaligned accesses, though it should be declared |
| // with the p2align attribute on loads and stores which do so, and there |
| // may be a performance impact. We tell LLVM they're "fast" because |
| // for the kinds of things that LLVM uses this for (merging adjacent stores |
| // of constants, etc.), WebAssembly implementations will either want the |
| // unaligned access or they'll split anyway. |
| if (Fast) |
| *Fast = true; |
| return true; |
| } |
| |
| bool WebAssemblyTargetLowering::isIntDivCheap(EVT VT, |
| AttributeList Attr) const { |
| // The current thinking is that wasm engines will perform this optimization, |
| // so we can save on code size. |
| return true; |
| } |
| |
| EVT WebAssemblyTargetLowering::getSetCCResultType(const DataLayout &DL, |
| LLVMContext &C, |
| EVT VT) const { |
| if (VT.isVector()) |
| return VT.changeVectorElementTypeToInteger(); |
| |
| return TargetLowering::getSetCCResultType(DL, C, VT); |
| } |
| |
| bool WebAssemblyTargetLowering::getTgtMemIntrinsic(IntrinsicInfo &Info, |
| const CallInst &I, |
| MachineFunction &MF, |
| unsigned Intrinsic) const { |
| switch (Intrinsic) { |
| case Intrinsic::wasm_atomic_notify: |
| Info.opc = ISD::INTRINSIC_W_CHAIN; |
| Info.memVT = MVT::i32; |
| Info.ptrVal = I.getArgOperand(0); |
| Info.offset = 0; |
| Info.align = 4; |
| // atomic.notify instruction does not really load the memory specified with |
| // this argument, but MachineMemOperand should either be load or store, so |
| // we set this to a load. |
| // FIXME Volatile isn't really correct, but currently all LLVM atomic |
| // instructions are treated as volatiles in the backend, so we should be |
| // consistent. The same applies for wasm_atomic_wait intrinsics too. |
| Info.flags = MachineMemOperand::MOVolatile | MachineMemOperand::MOLoad; |
| return true; |
| case Intrinsic::wasm_atomic_wait_i32: |
| Info.opc = ISD::INTRINSIC_W_CHAIN; |
| Info.memVT = MVT::i32; |
| Info.ptrVal = I.getArgOperand(0); |
| Info.offset = 0; |
| Info.align = 4; |
| Info.flags = MachineMemOperand::MOVolatile | MachineMemOperand::MOLoad; |
| return true; |
| case Intrinsic::wasm_atomic_wait_i64: |
| Info.opc = ISD::INTRINSIC_W_CHAIN; |
| Info.memVT = MVT::i64; |
| Info.ptrVal = I.getArgOperand(0); |
| Info.offset = 0; |
| Info.align = 8; |
| Info.flags = MachineMemOperand::MOVolatile | MachineMemOperand::MOLoad; |
| return true; |
| default: |
| return false; |
| } |
| } |
| |
| //===----------------------------------------------------------------------===// |
| // WebAssembly Lowering private implementation. |
| //===----------------------------------------------------------------------===// |
| |
| //===----------------------------------------------------------------------===// |
| // Lowering Code |
| //===----------------------------------------------------------------------===// |
| |
| static void fail(const SDLoc &DL, SelectionDAG &DAG, const char *Msg) { |
| MachineFunction &MF = DAG.getMachineFunction(); |
| DAG.getContext()->diagnose( |
| DiagnosticInfoUnsupported(MF.getFunction(), Msg, DL.getDebugLoc())); |
| } |
| |
| // Test whether the given calling convention is supported. |
| static bool callingConvSupported(CallingConv::ID CallConv) { |
| // We currently support the language-independent target-independent |
| // conventions. We don't yet have a way to annotate calls with properties like |
| // "cold", and we don't have any call-clobbered registers, so these are mostly |
| // all handled the same. |
| return CallConv == CallingConv::C || CallConv == CallingConv::Fast || |
| CallConv == CallingConv::Cold || |
| CallConv == CallingConv::PreserveMost || |
| CallConv == CallingConv::PreserveAll || |
| CallConv == CallingConv::CXX_FAST_TLS; |
| } |
| |
| SDValue |
| WebAssemblyTargetLowering::LowerCall(CallLoweringInfo &CLI, |
| SmallVectorImpl<SDValue> &InVals) const { |
| SelectionDAG &DAG = CLI.DAG; |
| SDLoc DL = CLI.DL; |
| SDValue Chain = CLI.Chain; |
| SDValue Callee = CLI.Callee; |
| MachineFunction &MF = DAG.getMachineFunction(); |
| auto Layout = MF.getDataLayout(); |
| |
| CallingConv::ID CallConv = CLI.CallConv; |
| if (!callingConvSupported(CallConv)) |
| fail(DL, DAG, |
| "WebAssembly doesn't support language-specific or target-specific " |
| "calling conventions yet"); |
| if (CLI.IsPatchPoint) |
| fail(DL, DAG, "WebAssembly doesn't support patch point yet"); |
| |
| // WebAssembly doesn't currently support explicit tail calls. If they are |
| // required, fail. Otherwise, just disable them. |
| if ((CallConv == CallingConv::Fast && CLI.IsTailCall && |
| MF.getTarget().Options.GuaranteedTailCallOpt) || |
| (CLI.CS && CLI.CS.isMustTailCall())) |
| fail(DL, DAG, "WebAssembly doesn't support tail call yet"); |
| CLI.IsTailCall = false; |
| |
| SmallVectorImpl<ISD::InputArg> &Ins = CLI.Ins; |
| if (Ins.size() > 1) |
| fail(DL, DAG, "WebAssembly doesn't support more than 1 returned value yet"); |
| |
| SmallVectorImpl<ISD::OutputArg> &Outs = CLI.Outs; |
| SmallVectorImpl<SDValue> &OutVals = CLI.OutVals; |
| unsigned NumFixedArgs = 0; |
| for (unsigned I = 0; I < Outs.size(); ++I) { |
| const ISD::OutputArg &Out = Outs[I]; |
| SDValue &OutVal = OutVals[I]; |
| if (Out.Flags.isNest()) |
| fail(DL, DAG, "WebAssembly hasn't implemented nest arguments"); |
| if (Out.Flags.isInAlloca()) |
| fail(DL, DAG, "WebAssembly hasn't implemented inalloca arguments"); |
| if (Out.Flags.isInConsecutiveRegs()) |
| fail(DL, DAG, "WebAssembly hasn't implemented cons regs arguments"); |
| if (Out.Flags.isInConsecutiveRegsLast()) |
| fail(DL, DAG, "WebAssembly hasn't implemented cons regs last arguments"); |
| if (Out.Flags.isByVal() && Out.Flags.getByValSize() != 0) { |
| auto &MFI = MF.getFrameInfo(); |
| int FI = MFI.CreateStackObject(Out.Flags.getByValSize(), |
| Out.Flags.getByValAlign(), |
| /*isSS=*/false); |
| SDValue SizeNode = |
| DAG.getConstant(Out.Flags.getByValSize(), DL, MVT::i32); |
| SDValue FINode = DAG.getFrameIndex(FI, getPointerTy(Layout)); |
| Chain = DAG.getMemcpy( |
| Chain, DL, FINode, OutVal, SizeNode, Out.Flags.getByValAlign(), |
| /*isVolatile*/ false, /*AlwaysInline=*/false, |
| /*isTailCall*/ false, MachinePointerInfo(), MachinePointerInfo()); |
| OutVal = FINode; |
| } |
| // Count the number of fixed args *after* legalization. |
| NumFixedArgs += Out.IsFixed; |
| } |
| |
| bool IsVarArg = CLI.IsVarArg; |
| auto PtrVT = getPointerTy(Layout); |
| |
| // Analyze operands of the call, assigning locations to each operand. |
| SmallVector<CCValAssign, 16> ArgLocs; |
| CCState CCInfo(CallConv, IsVarArg, MF, ArgLocs, *DAG.getContext()); |
| |
| if (IsVarArg) { |
| // Outgoing non-fixed arguments are placed in a buffer. First |
| // compute their offsets and the total amount of buffer space needed. |
| for (SDValue Arg : |
| make_range(OutVals.begin() + NumFixedArgs, OutVals.end())) { |
| EVT VT = Arg.getValueType(); |
| assert(VT != MVT::iPTR && "Legalized args should be concrete"); |
| Type *Ty = VT.getTypeForEVT(*DAG.getContext()); |
| unsigned Offset = CCInfo.AllocateStack(Layout.getTypeAllocSize(Ty), |
| Layout.getABITypeAlignment(Ty)); |
| CCInfo.addLoc(CCValAssign::getMem(ArgLocs.size(), VT.getSimpleVT(), |
| Offset, VT.getSimpleVT(), |
| CCValAssign::Full)); |
| } |
| } |
| |
| unsigned NumBytes = CCInfo.getAlignedCallFrameSize(); |
| |
| SDValue FINode; |
| if (IsVarArg && NumBytes) { |
| // For non-fixed arguments, next emit stores to store the argument values |
| // to the stack buffer at the offsets computed above. |
| int FI = MF.getFrameInfo().CreateStackObject(NumBytes, |
| Layout.getStackAlignment(), |
| /*isSS=*/false); |
| unsigned ValNo = 0; |
| SmallVector<SDValue, 8> Chains; |
| for (SDValue Arg : |
| make_range(OutVals.begin() + NumFixedArgs, OutVals.end())) { |
| assert(ArgLocs[ValNo].getValNo() == ValNo && |
| "ArgLocs should remain in order and only hold varargs args"); |
| unsigned Offset = ArgLocs[ValNo++].getLocMemOffset(); |
| FINode = DAG.getFrameIndex(FI, getPointerTy(Layout)); |
| SDValue Add = DAG.getNode(ISD::ADD, DL, PtrVT, FINode, |
| DAG.getConstant(Offset, DL, PtrVT)); |
| Chains.push_back( |
| DAG.getStore(Chain, DL, Arg, Add, |
| MachinePointerInfo::getFixedStack(MF, FI, Offset), 0)); |
| } |
| if (!Chains.empty()) |
| Chain = DAG.getNode(ISD::TokenFactor, DL, MVT::Other, Chains); |
| } else if (IsVarArg) { |
| FINode = DAG.getIntPtrConstant(0, DL); |
| } |
| |
| // Compute the operands for the CALLn node. |
| SmallVector<SDValue, 16> Ops; |
| Ops.push_back(Chain); |
| Ops.push_back(Callee); |
| |
| // Add all fixed arguments. Note that for non-varargs calls, NumFixedArgs |
| // isn't reliable. |
| Ops.append(OutVals.begin(), |
| IsVarArg ? OutVals.begin() + NumFixedArgs : OutVals.end()); |
| // Add a pointer to the vararg buffer. |
| if (IsVarArg) |
| Ops.push_back(FINode); |
| |
| SmallVector<EVT, 8> InTys; |
| for (const auto &In : Ins) { |
| assert(!In.Flags.isByVal() && "byval is not valid for return values"); |
| assert(!In.Flags.isNest() && "nest is not valid for return values"); |
| if (In.Flags.isInAlloca()) |
| fail(DL, DAG, "WebAssembly hasn't implemented inalloca return values"); |
| if (In.Flags.isInConsecutiveRegs()) |
| fail(DL, DAG, "WebAssembly hasn't implemented cons regs return values"); |
| if (In.Flags.isInConsecutiveRegsLast()) |
| fail(DL, DAG, |
| "WebAssembly hasn't implemented cons regs last return values"); |
| // Ignore In.getOrigAlign() because all our arguments are passed in |
| // registers. |
| InTys.push_back(In.VT); |
| } |
| InTys.push_back(MVT::Other); |
| SDVTList InTyList = DAG.getVTList(InTys); |
| SDValue Res = |
| DAG.getNode(Ins.empty() ? WebAssemblyISD::CALL0 : WebAssemblyISD::CALL1, |
| DL, InTyList, Ops); |
| if (Ins.empty()) { |
| Chain = Res; |
| } else { |
| InVals.push_back(Res); |
| Chain = Res.getValue(1); |
| } |
| |
| return Chain; |
| } |
| |
| bool WebAssemblyTargetLowering::CanLowerReturn( |
| CallingConv::ID /*CallConv*/, MachineFunction & /*MF*/, bool /*IsVarArg*/, |
| const SmallVectorImpl<ISD::OutputArg> &Outs, |
| LLVMContext & /*Context*/) const { |
| // WebAssembly can't currently handle returning tuples. |
| return Outs.size() <= 1; |
| } |
| |
| SDValue WebAssemblyTargetLowering::LowerReturn( |
| SDValue Chain, CallingConv::ID CallConv, bool /*IsVarArg*/, |
| const SmallVectorImpl<ISD::OutputArg> &Outs, |
| const SmallVectorImpl<SDValue> &OutVals, const SDLoc &DL, |
| SelectionDAG &DAG) const { |
| assert(Outs.size() <= 1 && "WebAssembly can only return up to one value"); |
| if (!callingConvSupported(CallConv)) |
| fail(DL, DAG, "WebAssembly doesn't support non-C calling conventions"); |
| |
| SmallVector<SDValue, 4> RetOps(1, Chain); |
| RetOps.append(OutVals.begin(), OutVals.end()); |
| Chain = DAG.getNode(WebAssemblyISD::RETURN, DL, MVT::Other, RetOps); |
| |
| // Record the number and types of the return values. |
| for (const ISD::OutputArg &Out : Outs) { |
| assert(!Out.Flags.isByVal() && "byval is not valid for return values"); |
| assert(!Out.Flags.isNest() && "nest is not valid for return values"); |
| assert(Out.IsFixed && "non-fixed return value is not valid"); |
| if (Out.Flags.isInAlloca()) |
| fail(DL, DAG, "WebAssembly hasn't implemented inalloca results"); |
| if (Out.Flags.isInConsecutiveRegs()) |
| fail(DL, DAG, "WebAssembly hasn't implemented cons regs results"); |
| if (Out.Flags.isInConsecutiveRegsLast()) |
| fail(DL, DAG, "WebAssembly hasn't implemented cons regs last results"); |
| } |
| |
| return Chain; |
| } |
| |
| SDValue WebAssemblyTargetLowering::LowerFormalArguments( |
| SDValue Chain, CallingConv::ID CallConv, bool IsVarArg, |
| const SmallVectorImpl<ISD::InputArg> &Ins, const SDLoc &DL, |
| SelectionDAG &DAG, SmallVectorImpl<SDValue> &InVals) const { |
| if (!callingConvSupported(CallConv)) |
| fail(DL, DAG, "WebAssembly doesn't support non-C calling conventions"); |
| |
| MachineFunction &MF = DAG.getMachineFunction(); |
| auto *MFI = MF.getInfo<WebAssemblyFunctionInfo>(); |
| |
| // Set up the incoming ARGUMENTS value, which serves to represent the liveness |
| // of the incoming values before they're represented by virtual registers. |
| MF.getRegInfo().addLiveIn(WebAssembly::ARGUMENTS); |
| |
| for (const ISD::InputArg &In : Ins) { |
| if (In.Flags.isInAlloca()) |
| fail(DL, DAG, "WebAssembly hasn't implemented inalloca arguments"); |
| if (In.Flags.isNest()) |
| fail(DL, DAG, "WebAssembly hasn't implemented nest arguments"); |
| if (In.Flags.isInConsecutiveRegs()) |
| fail(DL, DAG, "WebAssembly hasn't implemented cons regs arguments"); |
| if (In.Flags.isInConsecutiveRegsLast()) |
| fail(DL, DAG, "WebAssembly hasn't implemented cons regs last arguments"); |
| // Ignore In.getOrigAlign() because all our arguments are passed in |
| // registers. |
| InVals.push_back(In.Used ? DAG.getNode(WebAssemblyISD::ARGUMENT, DL, In.VT, |
| DAG.getTargetConstant(InVals.size(), |
| DL, MVT::i32)) |
| : DAG.getUNDEF(In.VT)); |
| |
| // Record the number and types of arguments. |
| MFI->addParam(In.VT); |
| } |
| |
| // Varargs are copied into a buffer allocated by the caller, and a pointer to |
| // the buffer is passed as an argument. |
| if (IsVarArg) { |
| MVT PtrVT = getPointerTy(MF.getDataLayout()); |
| unsigned VarargVreg = |
| MF.getRegInfo().createVirtualRegister(getRegClassFor(PtrVT)); |
| MFI->setVarargBufferVreg(VarargVreg); |
| Chain = DAG.getCopyToReg( |
| Chain, DL, VarargVreg, |
| DAG.getNode(WebAssemblyISD::ARGUMENT, DL, PtrVT, |
| DAG.getTargetConstant(Ins.size(), DL, MVT::i32))); |
| MFI->addParam(PtrVT); |
| } |
| |
| // Record the number and types of arguments and results. |
| SmallVector<MVT, 4> Params; |
| SmallVector<MVT, 4> Results; |
| computeSignatureVTs(MF.getFunction().getFunctionType(), MF.getFunction(), |
| DAG.getTarget(), Params, Results); |
| for (MVT VT : Results) |
| MFI->addResult(VT); |
| // TODO: Use signatures in WebAssemblyMachineFunctionInfo too and unify |
| // the param logic here with ComputeSignatureVTs |
| assert(MFI->getParams().size() == Params.size() && |
| std::equal(MFI->getParams().begin(), MFI->getParams().end(), |
| Params.begin())); |
| |
| return Chain; |
| } |
| |
| //===----------------------------------------------------------------------===// |
| // Custom lowering hooks. |
| //===----------------------------------------------------------------------===// |
| |
| SDValue WebAssemblyTargetLowering::LowerOperation(SDValue Op, |
| SelectionDAG &DAG) const { |
| SDLoc DL(Op); |
| switch (Op.getOpcode()) { |
| default: |
| llvm_unreachable("unimplemented operation lowering"); |
| return SDValue(); |
| case ISD::FrameIndex: |
| return LowerFrameIndex(Op, DAG); |
| case ISD::GlobalAddress: |
| return LowerGlobalAddress(Op, DAG); |
| case ISD::ExternalSymbol: |
| return LowerExternalSymbol(Op, DAG); |
| case ISD::JumpTable: |
| return LowerJumpTable(Op, DAG); |
| case ISD::BR_JT: |
| return LowerBR_JT(Op, DAG); |
| case ISD::VASTART: |
| return LowerVASTART(Op, DAG); |
| case ISD::BlockAddress: |
| case ISD::BRIND: |
| fail(DL, DAG, "WebAssembly hasn't implemented computed gotos"); |
| return SDValue(); |
| case ISD::RETURNADDR: // Probably nothing meaningful can be returned here. |
| fail(DL, DAG, "WebAssembly hasn't implemented __builtin_return_address"); |
| return SDValue(); |
| case ISD::FRAMEADDR: |
| return LowerFRAMEADDR(Op, DAG); |
| case ISD::CopyToReg: |
| return LowerCopyToReg(Op, DAG); |
| case ISD::EXTRACT_VECTOR_ELT: |
| case ISD::INSERT_VECTOR_ELT: |
| return LowerAccessVectorElement(Op, DAG); |
| case ISD::INTRINSIC_VOID: |
| case ISD::INTRINSIC_WO_CHAIN: |
| case ISD::INTRINSIC_W_CHAIN: |
| return LowerIntrinsic(Op, DAG); |
| case ISD::SIGN_EXTEND_INREG: |
| return LowerSIGN_EXTEND_INREG(Op, DAG); |
| case ISD::BUILD_VECTOR: |
| return LowerBUILD_VECTOR(Op, DAG); |
| case ISD::VECTOR_SHUFFLE: |
| return LowerVECTOR_SHUFFLE(Op, DAG); |
| case ISD::SHL: |
| case ISD::SRA: |
| case ISD::SRL: |
| return LowerShift(Op, DAG); |
| } |
| } |
| |
| SDValue WebAssemblyTargetLowering::LowerCopyToReg(SDValue Op, |
| SelectionDAG &DAG) const { |
| SDValue Src = Op.getOperand(2); |
| if (isa<FrameIndexSDNode>(Src.getNode())) { |
| // CopyToReg nodes don't support FrameIndex operands. Other targets select |
| // the FI to some LEA-like instruction, but since we don't have that, we |
| // need to insert some kind of instruction that can take an FI operand and |
| // produces a value usable by CopyToReg (i.e. in a vreg). So insert a dummy |
| // local.copy between Op and its FI operand. |
| SDValue Chain = Op.getOperand(0); |
| SDLoc DL(Op); |
| unsigned Reg = cast<RegisterSDNode>(Op.getOperand(1))->getReg(); |
| EVT VT = Src.getValueType(); |
| SDValue Copy(DAG.getMachineNode(VT == MVT::i32 ? WebAssembly::COPY_I32 |
| : WebAssembly::COPY_I64, |
| DL, VT, Src), |
| 0); |
| return Op.getNode()->getNumValues() == 1 |
| ? DAG.getCopyToReg(Chain, DL, Reg, Copy) |
| : DAG.getCopyToReg(Chain, DL, Reg, Copy, |
| Op.getNumOperands() == 4 ? Op.getOperand(3) |
| : SDValue()); |
| } |
| return SDValue(); |
| } |
| |
| SDValue WebAssemblyTargetLowering::LowerFrameIndex(SDValue Op, |
| SelectionDAG &DAG) const { |
| int FI = cast<FrameIndexSDNode>(Op)->getIndex(); |
| return DAG.getTargetFrameIndex(FI, Op.getValueType()); |
| } |
| |
| SDValue WebAssemblyTargetLowering::LowerFRAMEADDR(SDValue Op, |
| SelectionDAG &DAG) const { |
| // Non-zero depths are not supported by WebAssembly currently. Use the |
| // legalizer's default expansion, which is to return 0 (what this function is |
| // documented to do). |
| if (Op.getConstantOperandVal(0) > 0) |
| return SDValue(); |
| |
| DAG.getMachineFunction().getFrameInfo().setFrameAddressIsTaken(true); |
| EVT VT = Op.getValueType(); |
| unsigned FP = |
| Subtarget->getRegisterInfo()->getFrameRegister(DAG.getMachineFunction()); |
| return DAG.getCopyFromReg(DAG.getEntryNode(), SDLoc(Op), FP, VT); |
| } |
| |
| SDValue WebAssemblyTargetLowering::LowerGlobalAddress(SDValue Op, |
| SelectionDAG &DAG) const { |
| SDLoc DL(Op); |
| const auto *GA = cast<GlobalAddressSDNode>(Op); |
| EVT VT = Op.getValueType(); |
| assert(GA->getTargetFlags() == 0 && |
| "Unexpected target flags on generic GlobalAddressSDNode"); |
| if (GA->getAddressSpace() != 0) |
| fail(DL, DAG, "WebAssembly only expects the 0 address space"); |
| return DAG.getNode( |
| WebAssemblyISD::Wrapper, DL, VT, |
| DAG.getTargetGlobalAddress(GA->getGlobal(), DL, VT, GA->getOffset())); |
| } |
| |
| SDValue |
| WebAssemblyTargetLowering::LowerExternalSymbol(SDValue Op, |
| SelectionDAG &DAG) const { |
| SDLoc DL(Op); |
| const auto *ES = cast<ExternalSymbolSDNode>(Op); |
| EVT VT = Op.getValueType(); |
| assert(ES->getTargetFlags() == 0 && |
| "Unexpected target flags on generic ExternalSymbolSDNode"); |
| // Set the TargetFlags to 0x1 which indicates that this is a "function" |
| // symbol rather than a data symbol. We do this unconditionally even though |
| // we don't know anything about the symbol other than its name, because all |
| // external symbols used in target-independent SelectionDAG code are for |
| // functions. |
| return DAG.getNode( |
| WebAssemblyISD::Wrapper, DL, VT, |
| DAG.getTargetExternalSymbol(ES->getSymbol(), VT, |
| WebAssemblyII::MO_SYMBOL_FUNCTION)); |
| } |
| |
| SDValue WebAssemblyTargetLowering::LowerJumpTable(SDValue Op, |
| SelectionDAG &DAG) const { |
| // There's no need for a Wrapper node because we always incorporate a jump |
| // table operand into a BR_TABLE instruction, rather than ever |
| // materializing it in a register. |
| const JumpTableSDNode *JT = cast<JumpTableSDNode>(Op); |
| return DAG.getTargetJumpTable(JT->getIndex(), Op.getValueType(), |
| JT->getTargetFlags()); |
| } |
| |
| SDValue WebAssemblyTargetLowering::LowerBR_JT(SDValue Op, |
| SelectionDAG &DAG) const { |
| SDLoc DL(Op); |
| SDValue Chain = Op.getOperand(0); |
| const auto *JT = cast<JumpTableSDNode>(Op.getOperand(1)); |
| SDValue Index = Op.getOperand(2); |
| assert(JT->getTargetFlags() == 0 && "WebAssembly doesn't set target flags"); |
| |
| SmallVector<SDValue, 8> Ops; |
| Ops.push_back(Chain); |
| Ops.push_back(Index); |
| |
| MachineJumpTableInfo *MJTI = DAG.getMachineFunction().getJumpTableInfo(); |
| const auto &MBBs = MJTI->getJumpTables()[JT->getIndex()].MBBs; |
| |
| // Add an operand for each case. |
| for (auto MBB : MBBs) |
| Ops.push_back(DAG.getBasicBlock(MBB)); |
| |
| // TODO: For now, we just pick something arbitrary for a default case for now. |
| // We really want to sniff out the guard and put in the real default case (and |
| // delete the guard). |
| Ops.push_back(DAG.getBasicBlock(MBBs[0])); |
| |
| return DAG.getNode(WebAssemblyISD::BR_TABLE, DL, MVT::Other, Ops); |
| } |
| |
| SDValue WebAssemblyTargetLowering::LowerVASTART(SDValue Op, |
| SelectionDAG &DAG) const { |
| SDLoc DL(Op); |
| EVT PtrVT = getPointerTy(DAG.getMachineFunction().getDataLayout()); |
| |
| auto *MFI = DAG.getMachineFunction().getInfo<WebAssemblyFunctionInfo>(); |
| const Value *SV = cast<SrcValueSDNode>(Op.getOperand(2))->getValue(); |
| |
| SDValue ArgN = DAG.getCopyFromReg(DAG.getEntryNode(), DL, |
| MFI->getVarargBufferVreg(), PtrVT); |
| return DAG.getStore(Op.getOperand(0), DL, ArgN, Op.getOperand(1), |
| MachinePointerInfo(SV), 0); |
| } |
| |
| SDValue WebAssemblyTargetLowering::LowerIntrinsic(SDValue Op, |
| SelectionDAG &DAG) const { |
| MachineFunction &MF = DAG.getMachineFunction(); |
| unsigned IntNo; |
| switch (Op.getOpcode()) { |
| case ISD::INTRINSIC_VOID: |
| case ISD::INTRINSIC_W_CHAIN: |
| IntNo = cast<ConstantSDNode>(Op.getOperand(1))->getZExtValue(); |
| break; |
| case ISD::INTRINSIC_WO_CHAIN: |
| IntNo = cast<ConstantSDNode>(Op.getOperand(0))->getZExtValue(); |
| break; |
| default: |
| llvm_unreachable("Invalid intrinsic"); |
| } |
| SDLoc DL(Op); |
| |
| switch (IntNo) { |
| default: |
| return SDValue(); // Don't custom lower most intrinsics. |
| |
| case Intrinsic::wasm_lsda: { |
| EVT VT = Op.getValueType(); |
| const TargetLowering &TLI = DAG.getTargetLoweringInfo(); |
| MVT PtrVT = TLI.getPointerTy(DAG.getDataLayout()); |
| auto &Context = MF.getMMI().getContext(); |
| MCSymbol *S = Context.getOrCreateSymbol(Twine("GCC_except_table") + |
| Twine(MF.getFunctionNumber())); |
| return DAG.getNode(WebAssemblyISD::Wrapper, DL, VT, |
| DAG.getMCSymbol(S, PtrVT)); |
| } |
| |
| case Intrinsic::wasm_throw: { |
| // We only support C++ exceptions for now |
| int Tag = cast<ConstantSDNode>(Op.getOperand(2).getNode())->getZExtValue(); |
| if (Tag != CPP_EXCEPTION) |
| llvm_unreachable("Invalid tag!"); |
| const TargetLowering &TLI = DAG.getTargetLoweringInfo(); |
| MVT PtrVT = TLI.getPointerTy(DAG.getDataLayout()); |
| const char *SymName = MF.createExternalSymbolName("__cpp_exception"); |
| SDValue SymNode = |
| DAG.getNode(WebAssemblyISD::Wrapper, DL, PtrVT, |
| DAG.getTargetExternalSymbol( |
| SymName, PtrVT, WebAssemblyII::MO_SYMBOL_EVENT)); |
| return DAG.getNode(WebAssemblyISD::THROW, DL, |
| MVT::Other, // outchain type |
| { |
| Op.getOperand(0), // inchain |
| SymNode, // exception symbol |
| Op.getOperand(3) // thrown value |
| }); |
| } |
| } |
| } |
| |
| SDValue |
| WebAssemblyTargetLowering::LowerSIGN_EXTEND_INREG(SDValue Op, |
| SelectionDAG &DAG) const { |
| // If sign extension operations are disabled, allow sext_inreg only if operand |
| // is a vector extract. SIMD does not depend on sign extension operations, but |
| // allowing sext_inreg in this context lets us have simple patterns to select |
| // extract_lane_s instructions. Expanding sext_inreg everywhere would be |
| // simpler in this file, but would necessitate large and brittle patterns to |
| // undo the expansion and select extract_lane_s instructions. |
| assert(!Subtarget->hasSignExt() && Subtarget->hasSIMD128()); |
| if (Op.getOperand(0).getOpcode() == ISD::EXTRACT_VECTOR_ELT) |
| return Op; |
| // Otherwise expand |
| return SDValue(); |
| } |
| |
| SDValue WebAssemblyTargetLowering::LowerBUILD_VECTOR(SDValue Op, |
| SelectionDAG &DAG) const { |
| SDLoc DL(Op); |
| const EVT VecT = Op.getValueType(); |
| const EVT LaneT = Op.getOperand(0).getValueType(); |
| const size_t Lanes = Op.getNumOperands(); |
| auto IsConstant = [](const SDValue &V) { |
| return V.getOpcode() == ISD::Constant || V.getOpcode() == ISD::ConstantFP; |
| }; |
| |
| // Find the most common operand, which is approximately the best to splat |
| using Entry = std::pair<SDValue, size_t>; |
| SmallVector<Entry, 16> ValueCounts; |
| size_t NumConst = 0, NumDynamic = 0; |
| for (const SDValue &Lane : Op->op_values()) { |
| if (Lane.isUndef()) { |
| continue; |
| } else if (IsConstant(Lane)) { |
| NumConst++; |
| } else { |
| NumDynamic++; |
| } |
| auto CountIt = std::find_if(ValueCounts.begin(), ValueCounts.end(), |
| [&Lane](Entry A) { return A.first == Lane; }); |
| if (CountIt == ValueCounts.end()) { |
| ValueCounts.emplace_back(Lane, 1); |
| } else { |
| CountIt->second++; |
| } |
| } |
| auto CommonIt = |
| std::max_element(ValueCounts.begin(), ValueCounts.end(), |
| [](Entry A, Entry B) { return A.second < B.second; }); |
| assert(CommonIt != ValueCounts.end() && "Unexpected all-undef build_vector"); |
| SDValue SplatValue = CommonIt->first; |
| size_t NumCommon = CommonIt->second; |
| |
| // If v128.const is available, consider using it instead of a splat |
| if (Subtarget->hasUnimplementedSIMD128()) { |
| // {i32,i64,f32,f64}.const opcode, and value |
| const size_t ConstBytes = 1 + std::max(size_t(4), 16 / Lanes); |
| // SIMD prefix and opcode |
| const size_t SplatBytes = 2; |
| const size_t SplatConstBytes = SplatBytes + ConstBytes; |
| // SIMD prefix, opcode, and lane index |
| const size_t ReplaceBytes = 3; |
| const size_t ReplaceConstBytes = ReplaceBytes + ConstBytes; |
| // SIMD prefix, v128.const opcode, and 128-bit value |
| const size_t VecConstBytes = 18; |
| // Initial v128.const and a replace_lane for each non-const operand |
| const size_t ConstInitBytes = VecConstBytes + NumDynamic * ReplaceBytes; |
| // Initial splat and all necessary replace_lanes |
| const size_t SplatInitBytes = |
| IsConstant(SplatValue) |
| // Initial constant splat |
| ? (SplatConstBytes + |
| // Constant replace_lanes |
| (NumConst - NumCommon) * ReplaceConstBytes + |
| // Dynamic replace_lanes |
| (NumDynamic * ReplaceBytes)) |
| // Initial dynamic splat |
| : (SplatBytes + |
| // Constant replace_lanes |
| (NumConst * ReplaceConstBytes) + |
| // Dynamic replace_lanes |
| (NumDynamic - NumCommon) * ReplaceBytes); |
| if (ConstInitBytes < SplatInitBytes) { |
| // Create build_vector that will lower to initial v128.const |
| SmallVector<SDValue, 16> ConstLanes; |
| for (const SDValue &Lane : Op->op_values()) { |
| if (IsConstant(Lane)) { |
| ConstLanes.push_back(Lane); |
| } else if (LaneT.isFloatingPoint()) { |
| ConstLanes.push_back(DAG.getConstantFP(0, DL, LaneT)); |
| } else { |
| ConstLanes.push_back(DAG.getConstant(0, DL, LaneT)); |
| } |
| } |
| SDValue Result = DAG.getBuildVector(VecT, DL, ConstLanes); |
| // Add replace_lane instructions for non-const lanes |
| for (size_t I = 0; I < Lanes; ++I) { |
| const SDValue &Lane = Op->getOperand(I); |
| if (!Lane.isUndef() && !IsConstant(Lane)) |
| Result = DAG.getNode(ISD::INSERT_VECTOR_ELT, DL, VecT, Result, Lane, |
| DAG.getConstant(I, DL, MVT::i32)); |
| } |
| return Result; |
| } |
| } |
| // Use a splat for the initial vector |
| SDValue Result = DAG.getSplatBuildVector(VecT, DL, SplatValue); |
| // Add replace_lane instructions for other values |
| for (size_t I = 0; I < Lanes; ++I) { |
| const SDValue &Lane = Op->getOperand(I); |
| if (Lane != SplatValue) |
| Result = DAG.getNode(ISD::INSERT_VECTOR_ELT, DL, VecT, Result, Lane, |
| DAG.getConstant(I, DL, MVT::i32)); |
| } |
| return Result; |
| } |
| |
| SDValue |
| WebAssemblyTargetLowering::LowerVECTOR_SHUFFLE(SDValue Op, |
| SelectionDAG &DAG) const { |
| SDLoc DL(Op); |
| ArrayRef<int> Mask = cast<ShuffleVectorSDNode>(Op.getNode())->getMask(); |
| MVT VecType = Op.getOperand(0).getSimpleValueType(); |
| assert(VecType.is128BitVector() && "Unexpected shuffle vector type"); |
| size_t LaneBytes = VecType.getVectorElementType().getSizeInBits() / 8; |
| |
| // Space for two vector args and sixteen mask indices |
| SDValue Ops[18]; |
| size_t OpIdx = 0; |
| Ops[OpIdx++] = Op.getOperand(0); |
| Ops[OpIdx++] = Op.getOperand(1); |
| |
| // Expand mask indices to byte indices and materialize them as operands |
| for (int M : Mask) { |
| for (size_t J = 0; J < LaneBytes; ++J) { |
| // Lower undefs (represented by -1 in mask) to zero |
| uint64_t ByteIndex = M == -1 ? 0 : (uint64_t)M * LaneBytes + J; |
| Ops[OpIdx++] = DAG.getConstant(ByteIndex, DL, MVT::i32); |
| } |
| } |
| |
| return DAG.getNode(WebAssemblyISD::SHUFFLE, DL, Op.getValueType(), Ops); |
| } |
| |
| SDValue |
| WebAssemblyTargetLowering::LowerAccessVectorElement(SDValue Op, |
| SelectionDAG &DAG) const { |
| // Allow constant lane indices, expand variable lane indices |
| SDNode *IdxNode = Op.getOperand(Op.getNumOperands() - 1).getNode(); |
| if (isa<ConstantSDNode>(IdxNode) || IdxNode->isUndef()) |
| return Op; |
| else |
| // Perform default expansion |
| return SDValue(); |
| } |
| |
| static SDValue unrollVectorShift(SDValue Op, SelectionDAG &DAG) { |
| EVT LaneT = Op.getSimpleValueType().getVectorElementType(); |
| // 32-bit and 64-bit unrolled shifts will have proper semantics |
| if (LaneT.bitsGE(MVT::i32)) |
| return DAG.UnrollVectorOp(Op.getNode()); |
| // Otherwise mask the shift value to get proper semantics from 32-bit shift |
| SDLoc DL(Op); |
| SDValue ShiftVal = Op.getOperand(1); |
| uint64_t MaskVal = LaneT.getSizeInBits() - 1; |
| SDValue MaskedShiftVal = DAG.getNode( |
| ISD::AND, // mask opcode |
| DL, ShiftVal.getValueType(), // masked value type |
| ShiftVal, // original shift value operand |
| DAG.getConstant(MaskVal, DL, ShiftVal.getValueType()) // mask operand |
| ); |
| |
| return DAG.UnrollVectorOp( |
| DAG.getNode(Op.getOpcode(), // original shift opcode |
| DL, Op.getValueType(), // original return type |
| Op.getOperand(0), // original vector operand, |
| MaskedShiftVal // new masked shift value operand |
| ) |
| .getNode()); |
| } |
| |
| SDValue WebAssemblyTargetLowering::LowerShift(SDValue Op, |
| SelectionDAG &DAG) const { |
| SDLoc DL(Op); |
| |
| // Only manually lower vector shifts |
| assert(Op.getSimpleValueType().isVector()); |
| |
| // Expand all vector shifts until V8 fixes its implementation |
| // TODO: remove this once V8 is fixed |
| if (!Subtarget->hasUnimplementedSIMD128()) |
| return unrollVectorShift(Op, DAG); |
| |
| // Unroll non-splat vector shifts |
| BuildVectorSDNode *ShiftVec; |
| SDValue SplatVal; |
| if (!(ShiftVec = dyn_cast<BuildVectorSDNode>(Op.getOperand(1).getNode())) || |
| !(SplatVal = ShiftVec->getSplatValue())) |
| return unrollVectorShift(Op, DAG); |
| |
| // All splats except i64x2 const splats are handled by patterns |
| auto *SplatConst = dyn_cast<ConstantSDNode>(SplatVal); |
| if (!SplatConst || Op.getSimpleValueType() != MVT::v2i64) |
| return Op; |
| |
| // i64x2 const splats are custom lowered to avoid unnecessary wraps |
| unsigned Opcode; |
| switch (Op.getOpcode()) { |
| case ISD::SHL: |
| Opcode = WebAssemblyISD::VEC_SHL; |
| break; |
| case ISD::SRA: |
| Opcode = WebAssemblyISD::VEC_SHR_S; |
| break; |
| case ISD::SRL: |
| Opcode = WebAssemblyISD::VEC_SHR_U; |
| break; |
| default: |
| llvm_unreachable("unexpected opcode"); |
| } |
| APInt Shift = SplatConst->getAPIntValue().zextOrTrunc(32); |
| return DAG.getNode(Opcode, DL, Op.getValueType(), Op.getOperand(0), |
| DAG.getConstant(Shift, DL, MVT::i32)); |
| } |
| |
| //===----------------------------------------------------------------------===// |
| // WebAssembly Optimization Hooks |
| //===----------------------------------------------------------------------===// |
