| // WebAssemblyMCInstLower.cpp - Convert WebAssembly MachineInstr to an MCInst // |
| // |
| // 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 contains code to lower WebAssembly MachineInstrs to their |
| /// corresponding MCInst records. |
| /// |
| //===----------------------------------------------------------------------===// |
| |
| #include "WebAssemblyMCInstLower.h" |
| #include "MCTargetDesc/WebAssemblyMCAsmInfo.h" |
| #include "MCTargetDesc/WebAssemblyMCTargetDesc.h" |
| #include "TargetInfo/WebAssemblyTargetInfo.h" |
| #include "Utils/WebAssemblyTypeUtilities.h" |
| #include "WebAssemblyAsmPrinter.h" |
| #include "WebAssemblyMachineFunctionInfo.h" |
| #include "WebAssemblyUtilities.h" |
| #include "llvm/CodeGen/AsmPrinter.h" |
| #include "llvm/CodeGen/MachineFunction.h" |
| #include "llvm/IR/Constants.h" |
| #include "llvm/MC/MCAsmInfo.h" |
| #include "llvm/MC/MCContext.h" |
| #include "llvm/MC/MCExpr.h" |
| #include "llvm/MC/MCInst.h" |
| #include "llvm/MC/MCSymbolWasm.h" |
| #include "llvm/Support/ErrorHandling.h" |
| #include "llvm/Support/raw_ostream.h" |
| |
| using namespace llvm; |
| |
| // This disables the removal of registers when lowering into MC, as required |
| // by some current tests. |
| static cl::opt<bool> |
| WasmKeepRegisters("wasm-keep-registers", cl::Hidden, |
| cl::desc("WebAssembly: output stack registers in" |
| " instruction output for test purposes only."), |
| cl::init(false)); |
| |
| static void removeRegisterOperands(const MachineInstr *MI, MCInst &OutMI); |
| |
| MCSymbol * |
| WebAssemblyMCInstLower::GetGlobalAddressSymbol(const MachineOperand &MO) const { |
| const GlobalValue *Global = MO.getGlobal(); |
| if (!isa<Function>(Global)) { |
| auto *WasmSym = cast<MCSymbolWasm>(Printer.getSymbol(Global)); |
| // If the symbol doesn't have an explicit WasmSymbolType yet and the |
| // GlobalValue is actually a WebAssembly global, then ensure the symbol is a |
| // WASM_SYMBOL_TYPE_GLOBAL. |
| if (WebAssembly::isWasmVarAddressSpace(Global->getAddressSpace()) && |
| !WasmSym->getType()) { |
| const MachineFunction &MF = *MO.getParent()->getParent()->getParent(); |
| const TargetMachine &TM = MF.getTarget(); |
| const Function &CurrentFunc = MF.getFunction(); |
| Type *GlobalVT = Global->getValueType(); |
| SmallVector<MVT, 1> VTs; |
| computeLegalValueVTs(CurrentFunc, TM, GlobalVT, VTs); |
| |
| WebAssembly::wasmSymbolSetType(WasmSym, GlobalVT, VTs); |
| } |
| return WasmSym; |
| } |
| |
| const auto *FuncTy = cast<FunctionType>(Global->getValueType()); |
| const MachineFunction &MF = *MO.getParent()->getParent()->getParent(); |
| const TargetMachine &TM = MF.getTarget(); |
| const Function &CurrentFunc = MF.getFunction(); |
| |
| SmallVector<MVT, 1> ResultMVTs; |
| SmallVector<MVT, 4> ParamMVTs; |
| const auto *const F = dyn_cast<Function>(Global); |
| computeSignatureVTs(FuncTy, F, CurrentFunc, TM, ParamMVTs, ResultMVTs); |
| auto Signature = signatureFromMVTs(Ctx, ResultMVTs, ParamMVTs); |
| |
| bool InvokeDetected = false; |
| auto *WasmSym = Printer.getMCSymbolForFunction(F, Signature, InvokeDetected); |
| WasmSym->setSignature(Signature); |
| WasmSym->setType(wasm::WASM_SYMBOL_TYPE_FUNCTION); |
| return WasmSym; |
| } |
| |
| MCSymbol *WebAssemblyMCInstLower::GetExternalSymbolSymbol( |
| const MachineOperand &MO) const { |
| return Printer.getOrCreateWasmSymbol(MO.getSymbolName()); |
| } |
| |
| MCOperand WebAssemblyMCInstLower::lowerSymbolOperand(const MachineOperand &MO, |
| MCSymbol *Sym) const { |
| auto Spec = WebAssembly::S_None; |
| unsigned TargetFlags = MO.getTargetFlags(); |
| |
| switch (TargetFlags) { |
| case WebAssemblyII::MO_NO_FLAG: |
| break; |
| case WebAssemblyII::MO_GOT_TLS: |
| Spec = WebAssembly::S_GOT_TLS; |
| break; |
| case WebAssemblyII::MO_GOT: |
| Spec = WebAssembly::S_GOT; |
| break; |
| case WebAssemblyII::MO_MEMORY_BASE_REL: |
| Spec = WebAssembly::S_MBREL; |
| break; |
| case WebAssemblyII::MO_TLS_BASE_REL: |
| Spec = WebAssembly::S_TLSREL; |
| break; |
| case WebAssemblyII::MO_TABLE_BASE_REL: |
| Spec = WebAssembly::S_TBREL; |
| break; |
| default: |
| llvm_unreachable("Unknown target flag on GV operand"); |
| } |
| |
| const MCExpr *Expr = MCSymbolRefExpr::create(Sym, Spec, Ctx); |
| |
| if (MO.getOffset() != 0) { |
| const auto *WasmSym = cast<MCSymbolWasm>(Sym); |
| if (TargetFlags == WebAssemblyII::MO_GOT) |
| report_fatal_error("GOT symbol references do not support offsets"); |
| if (WasmSym->isFunction()) |
| report_fatal_error("Function addresses with offsets not supported"); |
| if (WasmSym->isGlobal()) |
| report_fatal_error("Global indexes with offsets not supported"); |
| if (WasmSym->isTag()) |
| report_fatal_error("Tag indexes with offsets not supported"); |
| if (WasmSym->isTable()) |
| report_fatal_error("Table indexes with offsets not supported"); |
| |
| Expr = MCBinaryExpr::createAdd( |
| Expr, MCConstantExpr::create(MO.getOffset(), Ctx), Ctx); |
| } |
| |
| return MCOperand::createExpr(Expr); |
| } |
| |
| MCOperand WebAssemblyMCInstLower::lowerTypeIndexOperand( |
| SmallVectorImpl<wasm::ValType> &&Returns, |
| SmallVectorImpl<wasm::ValType> &&Params) const { |
| auto Signature = Ctx.createWasmSignature(); |
| Signature->Returns = std::move(Returns); |
| Signature->Params = std::move(Params); |
| MCSymbol *Sym = Printer.createTempSymbol("typeindex"); |
| auto *WasmSym = cast<MCSymbolWasm>(Sym); |
| WasmSym->setSignature(Signature); |
| WasmSym->setType(wasm::WASM_SYMBOL_TYPE_FUNCTION); |
| const MCExpr *Expr = |
| MCSymbolRefExpr::create(WasmSym, WebAssembly::S_TYPEINDEX, Ctx); |
| return MCOperand::createExpr(Expr); |
| } |
| |
| static void getFunctionReturns(const MachineInstr *MI, |
| SmallVectorImpl<wasm::ValType> &Returns) { |
| const Function &F = MI->getMF()->getFunction(); |
| const TargetMachine &TM = MI->getMF()->getTarget(); |
| Type *RetTy = F.getReturnType(); |
| SmallVector<MVT, 4> CallerRetTys; |
| computeLegalValueVTs(F, TM, RetTy, CallerRetTys); |
| valTypesFromMVTs(CallerRetTys, Returns); |
| } |
| |
| void WebAssemblyMCInstLower::lower(const MachineInstr *MI, |
| MCInst &OutMI) const { |
| OutMI.setOpcode(MI->getOpcode()); |
| |
| const MCInstrDesc &Desc = MI->getDesc(); |
| unsigned NumVariadicDefs = MI->getNumExplicitDefs() - Desc.getNumDefs(); |
| const MachineFunction *MF = MI->getMF(); |
| const auto &TLI = |
| *MF->getSubtarget<WebAssemblySubtarget>().getTargetLowering(); |
| wasm::ValType PtrTy = TLI.getPointerTy(MF->getDataLayout()) == MVT::i32 |
| ? wasm::ValType::I32 |
| : wasm::ValType::I64; |
| |
| for (unsigned I = 0, E = MI->getNumOperands(); I != E; ++I) { |
| const MachineOperand &MO = MI->getOperand(I); |
| |
| MCOperand MCOp; |
| switch (MO.getType()) { |
| default: |
| MI->print(errs()); |
| llvm_unreachable("unknown operand type"); |
| case MachineOperand::MO_MachineBasicBlock: |
| MI->print(errs()); |
| llvm_unreachable("MachineBasicBlock operand should have been rewritten"); |
| case MachineOperand::MO_Register: { |
| // Ignore all implicit register operands. |
| if (MO.isImplicit()) |
| continue; |
| const WebAssemblyFunctionInfo &MFI = |
| *MI->getParent()->getParent()->getInfo<WebAssemblyFunctionInfo>(); |
| unsigned WAReg = MFI.getWAReg(MO.getReg()); |
| MCOp = MCOperand::createReg(WAReg); |
| break; |
| } |
| case MachineOperand::MO_Immediate: { |
| unsigned DescIndex = I - NumVariadicDefs; |
| if (DescIndex < Desc.NumOperands) { |
| const MCOperandInfo &Info = Desc.operands()[DescIndex]; |
| if (Info.OperandType == WebAssembly::OPERAND_TYPEINDEX) { |
| SmallVector<wasm::ValType, 4> Returns; |
| SmallVector<wasm::ValType, 4> Params; |
| |
| const MachineRegisterInfo &MRI = |
| MI->getParent()->getParent()->getRegInfo(); |
| for (const MachineOperand &MO : MI->defs()) |
| Returns.push_back(WebAssembly::regClassToValType( |
| MRI.getRegClass(MO.getReg())->getID())); |
| for (const MachineOperand &MO : MI->explicit_uses()) |
| if (MO.isReg()) |
| Params.push_back(WebAssembly::regClassToValType( |
| MRI.getRegClass(MO.getReg())->getID())); |
| |
| // call_indirect instructions have a callee operand at the end which |
| // doesn't count as a param. |
| if (WebAssembly::isCallIndirect(MI->getOpcode())) |
| Params.pop_back(); |
| |
| // return_call_indirect instructions have the return type of the |
| // caller |
| if (MI->getOpcode() == WebAssembly::RET_CALL_INDIRECT) |
| getFunctionReturns(MI, Returns); |
| |
| MCOp = lowerTypeIndexOperand(std::move(Returns), std::move(Params)); |
| break; |
| } |
| if (Info.OperandType == WebAssembly::OPERAND_SIGNATURE) { |
| auto BT = static_cast<WebAssembly::BlockType>(MO.getImm()); |
| assert(BT != WebAssembly::BlockType::Invalid); |
| if (BT == WebAssembly::BlockType::Multivalue) { |
| SmallVector<wasm::ValType, 2> Returns; |
| // Multivalue blocks are emitted in two cases: |
| // 1. When the blocks will never be exited and are at the ends of |
| // functions (see |
| // WebAssemblyCFGStackify::fixEndsAtEndOfFunction). In this case |
| // the exact multivalue signature can always be inferred from the |
| // return type of the parent function. |
| // 2. (catch_ref ...) clause in try_table instruction. Currently all |
| // tags we support (cpp_exception and c_longjmp) throws a single |
| // pointer, so the multivalue signature for this case will be |
| // (ptr, exnref). Having MO_CATCH_BLOCK_SIG target flags means |
| // this is a destination of a catch_ref. |
| if (MO.getTargetFlags() == WebAssemblyII::MO_CATCH_BLOCK_SIG) { |
| Returns = {PtrTy, wasm::ValType::EXNREF}; |
| } else |
| getFunctionReturns(MI, Returns); |
| MCOp = lowerTypeIndexOperand(std::move(Returns), |
| SmallVector<wasm::ValType, 4>()); |
| break; |
| } |
| } |
| } |
| MCOp = MCOperand::createImm(MO.getImm()); |
| break; |
| } |
| case MachineOperand::MO_FPImmediate: { |
| const ConstantFP *Imm = MO.getFPImm(); |
| const uint64_t BitPattern = |
| Imm->getValueAPF().bitcastToAPInt().getZExtValue(); |
| if (Imm->getType()->isFloatTy()) |
| MCOp = MCOperand::createSFPImm(static_cast<uint32_t>(BitPattern)); |
| else if (Imm->getType()->isDoubleTy()) |
| MCOp = MCOperand::createDFPImm(BitPattern); |
| else |
| llvm_unreachable("unknown floating point immediate type"); |
| break; |
| } |
| case MachineOperand::MO_GlobalAddress: |
| MCOp = lowerSymbolOperand(MO, GetGlobalAddressSymbol(MO)); |
| break; |
| case MachineOperand::MO_ExternalSymbol: |
| MCOp = lowerSymbolOperand(MO, GetExternalSymbolSymbol(MO)); |
| break; |
| case MachineOperand::MO_MCSymbol: |
| assert(MO.getTargetFlags() == 0 && |
| "WebAssembly does not use target flags on MCSymbol"); |
| MCOp = lowerSymbolOperand(MO, MO.getMCSymbol()); |
| break; |
| } |
| |
| OutMI.addOperand(MCOp); |
| } |
| |
| if (!WasmKeepRegisters) |
| removeRegisterOperands(MI, OutMI); |
| else if (Desc.variadicOpsAreDefs()) |
| OutMI.insert(OutMI.begin(), MCOperand::createImm(MI->getNumExplicitDefs())); |
| } |
| |
| static void removeRegisterOperands(const MachineInstr *MI, MCInst &OutMI) { |
| // Remove all uses of stackified registers to bring the instruction format |
| // into its final stack form used thruout MC, and transition opcodes to |
| // their _S variant. |
| // We do this separate from the above code that still may need these |
| // registers for e.g. call_indirect signatures. |
| // See comments in lib/Target/WebAssembly/WebAssemblyInstrFormats.td for |
| // details. |
| // TODO: the code above creates new registers which are then removed here. |
| // That code could be slightly simplified by not doing that, though maybe |
| // it is simpler conceptually to keep the code above in "register mode" |
| // until this transition point. |
| // FIXME: we are not processing inline assembly, which contains register |
| // operands, because it is used by later target generic code. |
| if (MI->isDebugInstr() || MI->isLabel() || MI->isInlineAsm()) |
| return; |
| |
| // Transform to _S instruction. |
| auto RegOpcode = OutMI.getOpcode(); |
| auto StackOpcode = WebAssembly::getStackOpcode(RegOpcode); |
| assert(StackOpcode != -1 && "Failed to stackify instruction"); |
| OutMI.setOpcode(StackOpcode); |
| |
| // Remove register operands. |
| for (auto I = OutMI.getNumOperands(); I; --I) { |
| auto &MO = OutMI.getOperand(I - 1); |
| if (MO.isReg()) { |
| OutMI.erase(&MO); |
| } |
| } |
| } |
