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::SWITCH, DL, MVT::Other, Ops);
}
void JITEmitter::startFunction(MachineFunction &F) {
uintptr_t ActualSize = 0;
if (MemMgr->NeedsExactSize()) {
const TargetInstrInfo* TII = F.getTarget().getInstrInfo();
MachineJumpTableInfo *MJTI = F.getJumpTableInfo();
MachineConstantPool *MCP = F.getConstantPool();
// Ensure the constant pool/jump table info is at least 4-byte aligned.
ActualSize = RoundUpToAlign(ActualSize, 16);
// Add the alignment of the constant pool
ActualSize = RoundUpToAlign(ActualSize,
1 << MCP->getConstantPoolAlignment());
// Add the constant pool size
ActualSize += GetConstantPoolSizeInBytes(MCP);
// Add the aligment of the jump table info
ActualSize = RoundUpToAlign(ActualSize, MJTI->getAlignment());
// Add the jump table size
ActualSize += GetJumpTableSizeInBytes(MJTI);
// Add the alignment for the function
ActualSize = RoundUpToAlign(ActualSize,
std::max(F.getFunction()->getAlignment(), 8U));
// Add the function size
ActualSize += TII->GetFunctionSizeInBytes(F);
}
BufferBegin = CurBufferPtr = MemMgr->startFunctionBody(F.getFunction(),
ActualSize);
BufferEnd = BufferBegin+ActualSize;
// Ensure the constant pool/jump table info is at least 4-byte aligned.
emitAlignment(16);
emitConstantPool(F.getConstantPool());
initJumpTableInfo(F.getJumpTableInfo());
// About to start emitting the machine code for the function.
emitAlignment(std::max(F.getFunction()->getAlignment(), 8U));
TheJIT->updateGlobalMapping(F.getFunction(), CurBufferPtr);
MBBLocations.clear();
}
void MIRPrinter::convert(ModuleSlotTracker &MST,
yaml::MachineJumpTable &YamlJTI,
const MachineJumpTableInfo &JTI) {
YamlJTI.Kind = JTI.getEntryKind();
unsigned ID = 0;
for (const auto &Table : JTI.getJumpTables()) {
std::string Str;
yaml::MachineJumpTable::Entry Entry;
Entry.ID = ID++;
for (const auto *MBB : Table.MBBs) {
raw_string_ostream StrOS(Str);
StrOS << printMBBReference(*MBB);
Entry.Blocks.push_back(StrOS.str());
Str.clear();
}
YamlJTI.Entries.push_back(Entry);
}
}
bool MIRParserImpl::initializeJumpTableInfo(
MachineFunction &MF, const yaml::MachineJumpTable &YamlJTI,
PerFunctionMIParsingState &PFS) {
MachineJumpTableInfo *JTI = MF.getOrCreateJumpTableInfo(YamlJTI.Kind);
SMDiagnostic Error;
for (const auto &Entry : YamlJTI.Entries) {
std::vector<MachineBasicBlock *> Blocks;
for (const auto &MBBSource : Entry.Blocks) {
MachineBasicBlock *MBB = nullptr;
if (parseMBBReference(MBB, MBBSource.Value, MF, PFS))
return true;
Blocks.push_back(MBB);
}
unsigned Index = JTI->createJumpTableIndex(Blocks);
// TODO: Report an error when the same jump table slot ID is redefined.
PFS.JumpTableSlots.insert(std::make_pair(Entry.ID, Index));
}
return false;
}
bool MIRParserImpl::initializeJumpTableInfo(PerFunctionMIParsingState &PFS,
const yaml::MachineJumpTable &YamlJTI) {
MachineJumpTableInfo *JTI = PFS.MF.getOrCreateJumpTableInfo(YamlJTI.Kind);
for (const auto &Entry : YamlJTI.Entries) {
std::vector<MachineBasicBlock *> Blocks;
for (const auto &MBBSource : Entry.Blocks) {
MachineBasicBlock *MBB = nullptr;
if (parseMBBReference(PFS, MBB, MBBSource.Value))
return true;
Blocks.push_back(MBB);
}
unsigned Index = JTI->createJumpTableIndex(Blocks);
if (!PFS.JumpTableSlots.insert(std::make_pair(Entry.ID.Value, Index))
.second)
return error(Entry.ID.SourceRange.Start,
Twine("redefinition of jump table entry '%jump-table.") +
Twine(Entry.ID.Value) + "'");
}
return false;
}