#include "WebAssemblyTargetMachine.h"
#include "WebAssemblyTargetObjectFile.h"
#include "llvm/CodeGen/Analysis.h"
+#include "llvm/CodeGen/CallingConvLower.h"
+#include "llvm/CodeGen/MachineJumpTableInfo.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/CodeGen/SelectionDAG.h"
#include "llvm/IR/DiagnosticInfo.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"
namespace {
// Diagnostic information for unimplemented or unsupported feature reporting.
-// FIXME copied from BPF and AMDGPU.
-class DiagnosticInfoUnsupported : public DiagnosticInfo {
+// TODO: This code is copied from BPF and AMDGPU; consider factoring it out
+// and sharing code.
+class DiagnosticInfoUnsupported final : public DiagnosticInfo {
private:
// Debug location where this diagnostic is triggered.
DebugLoc DLoc;
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);
// WebAssembly does not produce floating-point exceptions on normal floating
setStackPointerRegisterToSaveRestore(
Subtarget->hasAddr64() ? WebAssembly::SP64 : WebAssembly::SP32);
// Set up the register classes.
- addRegisterClass(MVT::i32, &WebAssembly::Int32RegClass);
- addRegisterClass(MVT::i64, &WebAssembly::Int64RegClass);
- addRegisterClass(MVT::f32, &WebAssembly::Float32RegClass);
- addRegisterClass(MVT::f64, &WebAssembly::Float64RegClass);
+ addRegisterClass(MVT::i32, &WebAssembly::I32RegClass);
+ addRegisterClass(MVT::i64, &WebAssembly::I64RegClass);
+ addRegisterClass(MVT::f32, &WebAssembly::F32RegClass);
+ addRegisterClass(MVT::f64, &WebAssembly::F64RegClass);
// Compute derived properties from the register classes.
computeRegisterProperties(Subtarget->getRegisterInfo());
- // FIXME: many setOperationAction are missing...
+ setOperationAction(ISD::GlobalAddress, MVTPtr, Custom);
+ setOperationAction(ISD::ExternalSymbol, MVTPtr, Custom);
+ setOperationAction(ISD::JumpTable, MVTPtr, Custom);
for (auto T : {MVT::f32, MVT::f64}) {
// Don't expand the floating-point types to constant pools.
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})
+ for (auto Op :
+ {ISD::FCEIL, ISD::FFLOOR, ISD::FTRUNC, ISD::FNEARBYINT, ISD::FRINT})
setOperationAction(Op, T, Legal);
+ // Support minnan and maxnan, which otherwise default to expand.
+ setOperationAction(ISD::FMINNAN, T, Legal);
+ setOperationAction(ISD::FMAXNAN, T, Legal);
}
for (auto T : {MVT::i32, MVT::i64}) {
// Expand unavailable integer operations.
- for (auto Op : {ISD::BSWAP, ISD::ROTL, ISD::ROTR,
- 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 Op :
+ {ISD::BSWAP, ISD::ROTL, ISD::ROTR, 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}) {
setOperationAction(Op, 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, MVT::i32, Expand);
+ setOperationAction(ISD::DYNAMIC_STACKALLOC, MVTPtr, Expand);
+
+ // 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.
+ setLoadExtAction(ISD::EXTLOAD, MVT::f32, MVT::f64, 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);
+
+ // Trap lowers to wasm unreachable
+ setOperationAction(ISD::TRAP, MVT::Other, Legal);
+}
+
+FastISel *WebAssemblyTargetLowering::createFastISel(
+ FunctionLoweringInfo &FuncInfo, const TargetLibraryInfo *LibInfo) const {
+ return WebAssembly::createFastISel(FuncInfo, LibInfo);
}
-MVT WebAssemblyTargetLowering::getScalarShiftAmountTy(const DataLayout &DL,
+bool WebAssemblyTargetLowering::isOffsetFoldingLegal(
+ const GlobalAddressSDNode * /*GA*/) const {
+ // The WebAssembly target doesn't support folding offsets into global
+ // addresses.
+ return false;
+}
+
+MVT WebAssemblyTargetLowering::getScalarShiftAmountTy(const DataLayout & /*DL*/,
EVT VT) const {
return VT.getSimpleVT();
}
const char *
WebAssemblyTargetLowering::getTargetNodeName(unsigned Opcode) const {
switch (static_cast<WebAssemblyISD::NodeType>(Opcode)) {
- case WebAssemblyISD::FIRST_NUMBER: break;
- case WebAssemblyISD::RETURN: return "WebAssemblyISD::RETURN";
- case WebAssemblyISD::ARGUMENT: return "WebAssemblyISD::ARGUMENT";
+ 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':
+ if (VT == MVT::i32)
+ return std::make_pair(0U, &WebAssembly::I32RegClass);
+ if (VT == MVT::i64)
+ 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;
+}
+
//===----------------------------------------------------------------------===//
// WebAssembly Lowering private implementation.
//===----------------------------------------------------------------------===//
DiagnosticInfoUnsupported(DL, *MF.getFunction(), msg, SDValue()));
}
+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();
+
+ CallingConv::ID CallConv = CLI.CallConv;
+ if (CallConv != CallingConv::C && CallConv != CallingConv::Fast &&
+ CallConv != CallingConv::Cold)
+ 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<SDValue> &OutVals = CLI.OutVals;
+
+ SmallVectorImpl<ISD::InputArg> &Ins = CLI.Ins;
+ if (Ins.size() > 1)
+ fail(DL, DAG, "WebAssembly doesn't support more than 1 returned value yet");
+
+ bool IsVarArg = CLI.IsVarArg;
+ if (IsVarArg)
+ fail(DL, DAG, "WebAssembly doesn't support varargs yet");
+
+ // Analyze operands of the call, assigning locations to each operand.
+ SmallVector<CCValAssign, 16> ArgLocs;
+ CCState CCInfo(CallConv, IsVarArg, MF, ArgLocs, *DAG.getContext());
+ unsigned NumBytes = CCInfo.getNextStackOffset();
+
+ auto PtrVT = getPointerTy(MF.getDataLayout());
+ auto Zero = DAG.getConstant(0, DL, PtrVT, true);
+ auto NB = DAG.getConstant(NumBytes, DL, PtrVT, true);
+ Chain = DAG.getCALLSEQ_START(Chain, NB, DL);
+
+ SmallVector<SDValue, 16> Ops;
+ Ops.push_back(Chain);
+ Ops.push_back(Callee);
+ Ops.append(OutVals.begin(), OutVals.end());
+
+ SmallVector<EVT, 8> Tys;
+ for (const auto &In : Ins)
+ Tys.push_back(In.VT);
+ Tys.push_back(MVT::Other);
+ SDVTList TyList = DAG.getVTList(Tys);
+ SDValue Res =
+ DAG.getNode(Ins.empty() ? WebAssemblyISD::CALL0 : WebAssemblyISD::CALL1,
+ DL, TyList, Ops);
+ if (Ins.empty()) {
+ Chain = Res;
+ } else {
+ InVals.push_back(Res);
+ Chain = Res.getValue(1);
+ }
+
+ Chain = DAG.getCALLSEQ_END(Chain, NB, Zero, SDValue(), DL);
+
+ return Chain;
+}
+
bool WebAssemblyTargetLowering::CanLowerReturn(
- CallingConv::ID CallConv, MachineFunction &MF, bool IsVarArg,
- const SmallVectorImpl<ISD::OutputArg> &Outs, LLVMContext &Context) const {
+ 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;
}
const SmallVectorImpl<ISD::OutputArg> &Outs,
const SmallVectorImpl<SDValue> &OutVals, SDLoc DL,
SelectionDAG &DAG) const {
-
assert(Outs.size() <= 1 && "WebAssembly can only return up to one value");
if (CallConv != CallingConv::C)
fail(DL, DAG, "WebAssembly doesn't support non-C calling conventions");
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");
+ 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");
+ if (!Out.IsFixed)
+ fail(DL, DAG, "WebAssembly doesn't support non-fixed results yet");
+ }
+
return Chain;
}
fail(DL, DAG, "WebAssembly doesn't support non-C calling conventions");
if (IsVarArg)
fail(DL, DAG, "WebAssembly doesn't support varargs yet");
- if (MF.getFunction()->hasStructRetAttr())
- fail(DL, DAG, "WebAssembly doesn't support struct return yet");
- unsigned ArgNo = 0;
+ // 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.isZExt())
- fail(DL, DAG, "WebAssembly hasn't implemented zext arguments");
- if (In.Flags.isSExt())
- fail(DL, DAG, "WebAssembly hasn't implemented sext arguments");
- if (In.Flags.isInReg())
- fail(DL, DAG, "WebAssembly hasn't implemented inreg arguments");
- if (In.Flags.isSRet())
- fail(DL, DAG, "WebAssembly hasn't implemented sret arguments");
if (In.Flags.isByVal())
fail(DL, DAG, "WebAssembly hasn't implemented byval arguments");
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.isReturned())
- fail(DL, DAG, "WebAssembly hasn't implemented returned 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");
- if (In.Flags.isSplit())
- fail(DL, DAG, "WebAssembly hasn't implemented split arguments");
- // FIXME Do something with In.getOrigAlign()?
+ // 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(ArgNo, DL, MVT::i32))
+ DAG.getTargetConstant(InVals.size(), DL, MVT::i32))
: DAG.getNode(ISD::UNDEF, DL, In.VT));
- ++ArgNo;
+
+ // Record the number and types of arguments.
+ MF.getInfo<WebAssemblyFunctionInfo>()->addParam(In.VT);
}
return Chain;
}
//===----------------------------------------------------------------------===//
-// Other Lowering Code
+// Custom lowering hooks.
//===----------------------------------------------------------------------===//
+SDValue WebAssemblyTargetLowering::LowerOperation(SDValue Op,
+ SelectionDAG &DAG) const {
+ switch (Op.getOpcode()) {
+ default:
+ llvm_unreachable("unimplemented operation lowering");
+ return SDValue();
+ 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);
+ }
+}
+
+SDValue WebAssemblyTargetLowering::LowerGlobalAddress(SDValue Op,
+ SelectionDAG &DAG) const {
+ SDLoc DL(Op);
+ const auto *GA = cast<GlobalAddressSDNode>(Op);
+ EVT VT = Op.getValueType();
+ assert(GA->getOffset() == 0 &&
+ "offsets on global addresses are forbidden by isOffsetFoldingLegal");
+ assert(GA->getTargetFlags() == 0 && "WebAssembly doesn't set target flags");
+ 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));
+}
+
+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 && "WebAssembly doesn't set target flags");
+ return DAG.getNode(WebAssemblyISD::Wrapper, DL, VT,
+ DAG.getTargetExternalSymbol(ES->getSymbol(), VT));
+}
+
+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 TABLESWITCH 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;
+
+ // 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]));
+
+ // Add an operand for each case.
+ for (auto MBB : MBBs)
+ Ops.push_back(DAG.getBasicBlock(MBB));
+
+ return DAG.getNode(WebAssemblyISD::TABLESWITCH, DL, MVT::Other, Ops);
+}
+
//===----------------------------------------------------------------------===//
// WebAssembly Optimization Hooks
//===----------------------------------------------------------------------===//
MCSection *WebAssemblyTargetObjectFile::SelectSectionForGlobal(
- const GlobalValue *GV, SectionKind Kind, Mangler &Mang,
- const TargetMachine &TM) const {
- return getDataSection();
+ const GlobalValue *GV, SectionKind /*Kind*/, Mangler & /*Mang*/,
+ const TargetMachine & /*TM*/) const {
+ // TODO: Be more sophisticated than this.
+ return isa<Function>(GV) ? getTextSection() : getDataSection();
}
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