BasicBlock* Decompiler::decompileBasicBlock(MachineBasicBlock *MBB,
Function *F) {
// Create a Selection DAG of MachineSDNodes
DAG = createDAGFromMachineBasicBlock(MBB);
if (ViewMCDAGs) {
MBB->print(Infos);
DAG->viewGraph(MBB->getName());
}
// Run the engine to decompile into SDNodes
InvISel->SetDAG(DAG);
DAG->AssignTopologicalOrder();
// This sets the use on the first node and prevents root from being deleted.
HandleSDNode Dummy(DAG->getRoot());
// Start at root and go to entry token
SelectionDAG::allnodes_iterator ISelPosition(DAG->getRoot().getNode());
++ISelPosition;
// Make sure that ISelPosition gets properly updated when nodes are deleted
// in calls made from this function.
ISelUpdater ISU(*DAG, ISelPosition);
while (ISelPosition != DAG->allnodes_begin()) {
SDNode *Node = --ISelPosition;
for (SelectionDAG::allnodes_iterator beg = DAG->allnodes_begin(),
end = DAG->allnodes_end(); beg != end; ++beg) {
DEBUG(errs() << "Current Node: ";);
DEBUG(Node->dump());
DEBUG(beg->dump());
}
// Skip dead nodes
// if (Node->use_empty())
// continue;
SDNode *ResNode = InvISel->Transmogrify(Node);
if (ResNode == Node || Node->getOpcode() == ISD::DELETED_NODE)
continue;
if (ResNode) {
DAG->ReplaceAllUsesWith(Node, ResNode);
}
if (Node->use_empty()) {
DAG->RemoveDeadNode(Node);
}
}
/// This is the main entry point for the type legalizer. This does a top-down
/// traversal of the dag, legalizing types as it goes. Returns "true" if it made
/// any changes.
bool DAGTypeLegalizer::run() {
bool Changed = false;
// Create a dummy node (which is not added to allnodes), that adds a reference
// to the root node, preventing it from being deleted, and tracking any
// changes of the root.
HandleSDNode Dummy(DAG.getRoot());
Dummy.setNodeId(Unanalyzed);
// The root of the dag may dangle to deleted nodes until the type legalizer is
// done. Set it to null to avoid confusion.
DAG.setRoot(SDValue());
// Walk all nodes in the graph, assigning them a NodeId of 'ReadyToProcess'
// (and remembering them) if they are leaves and assigning 'Unanalyzed' if
// non-leaves.
for (SDNode &Node : DAG.allnodes()) {
if (Node.getNumOperands() == 0) {
AddToWorklist(&Node);
} else {
Node.setNodeId(Unanalyzed);
}
}
// Now that we have a set of nodes to process, handle them all.
while (!Worklist.empty()) {
#ifndef EXPENSIVE_CHECKS
if (EnableExpensiveChecks)
#endif
PerformExpensiveChecks();
SDNode *N = Worklist.back();
Worklist.pop_back();
assert(N->getNodeId() == ReadyToProcess &&
"Node should be ready if on worklist!");
if (IgnoreNodeResults(N))
goto ScanOperands;
// Scan the values produced by the node, checking to see if any result
// types are illegal.
for (unsigned i = 0, NumResults = N->getNumValues(); i < NumResults; ++i) {
EVT ResultVT = N->getValueType(i);
switch (getTypeAction(ResultVT)) {
case TargetLowering::TypeLegal:
break;
// The following calls must take care of *all* of the node's results,
// not just the illegal result they were passed (this includes results
// with a legal type). Results can be remapped using ReplaceValueWith,
// or their promoted/expanded/etc values registered in PromotedIntegers,
// ExpandedIntegers etc.
case TargetLowering::TypePromoteInteger:
PromoteIntegerResult(N, i);
Changed = true;
goto NodeDone;
case TargetLowering::TypeExpandInteger:
ExpandIntegerResult(N, i);
Changed = true;
goto NodeDone;
case TargetLowering::TypeSoftenFloat:
Changed = SoftenFloatResult(N, i);
if (Changed)
goto NodeDone;
// If not changed, the result type should be legally in register.
assert(isLegalInHWReg(ResultVT) &&
"Unchanged SoftenFloatResult should be legal in register!");
goto ScanOperands;
case TargetLowering::TypeExpandFloat:
ExpandFloatResult(N, i);
Changed = true;
goto NodeDone;
case TargetLowering::TypeScalarizeVector:
ScalarizeVectorResult(N, i);
Changed = true;
goto NodeDone;
case TargetLowering::TypeSplitVector:
SplitVectorResult(N, i);
Changed = true;
goto NodeDone;
case TargetLowering::TypeWidenVector:
WidenVectorResult(N, i);
Changed = true;
goto NodeDone;
case TargetLowering::TypePromoteFloat:
PromoteFloatResult(N, i);
Changed = true;
goto NodeDone;
}
}
ScanOperands:
// Scan the operand list for the node, handling any nodes with operands that
// are illegal.
{
unsigned NumOperands = N->getNumOperands();
bool NeedsReanalyzing = false;
unsigned i;
for (i = 0; i != NumOperands; ++i) {
if (IgnoreNodeResults(N->getOperand(i).getNode()))
continue;
EVT OpVT = N->getOperand(i).getValueType();
switch (getTypeAction(OpVT)) {
case TargetLowering::TypeLegal:
continue;
// The following calls must either replace all of the node's results
// using ReplaceValueWith, and return "false"; or update the node's
// operands in place, and return "true".
case TargetLowering::TypePromoteInteger:
NeedsReanalyzing = PromoteIntegerOperand(N, i);
Changed = true;
break;
case TargetLowering::TypeExpandInteger:
NeedsReanalyzing = ExpandIntegerOperand(N, i);
Changed = true;
break;
case TargetLowering::TypeSoftenFloat:
NeedsReanalyzing = SoftenFloatOperand(N, i);
Changed = true;
break;
case TargetLowering::TypeExpandFloat:
NeedsReanalyzing = ExpandFloatOperand(N, i);
Changed = true;
break;
case TargetLowering::TypeScalarizeVector:
NeedsReanalyzing = ScalarizeVectorOperand(N, i);
Changed = true;
break;
case TargetLowering::TypeSplitVector:
NeedsReanalyzing = SplitVectorOperand(N, i);
Changed = true;
break;
case TargetLowering::TypeWidenVector:
NeedsReanalyzing = WidenVectorOperand(N, i);
Changed = true;
break;
case TargetLowering::TypePromoteFloat:
NeedsReanalyzing = PromoteFloatOperand(N, i);
Changed = true;
break;
}
break;
}
// The sub-method updated N in place. Check to see if any operands are new,
// and if so, mark them. If the node needs revisiting, don't add all users
// to the worklist etc.
if (NeedsReanalyzing) {
assert(N->getNodeId() == ReadyToProcess && "Node ID recalculated?");
N->setNodeId(NewNode);
// Recompute the NodeId and correct processed operands, adding the node to
// the worklist if ready.
SDNode *M = AnalyzeNewNode(N);
if (M == N)
// The node didn't morph - nothing special to do, it will be revisited.
continue;
// The node morphed - this is equivalent to legalizing by replacing every
// value of N with the corresponding value of M. So do that now.
assert(N->getNumValues() == M->getNumValues() &&
"Node morphing changed the number of results!");
for (unsigned i = 0, e = N->getNumValues(); i != e; ++i)
// Replacing the value takes care of remapping the new value.
ReplaceValueWith(SDValue(N, i), SDValue(M, i));
assert(N->getNodeId() == NewNode && "Unexpected node state!");
// The node continues to live on as part of the NewNode fungus that
// grows on top of the useful nodes. Nothing more needs to be done
// with it - move on to the next node.
continue;
}
if (i == NumOperands) {
DEBUG(dbgs() << "Legally typed node: "; N->dump(&DAG); dbgs() << "\n");
}
}
NodeDone:
// If we reach here, the node was processed, potentially creating new nodes.
// Mark it as processed and add its users to the worklist as appropriate.
assert(N->getNodeId() == ReadyToProcess && "Node ID recalculated?");
N->setNodeId(Processed);
for (SDNode::use_iterator UI = N->use_begin(), E = N->use_end();
UI != E; ++UI) {
SDNode *User = *UI;
int NodeId = User->getNodeId();
// This node has two options: it can either be a new node or its Node ID
// may be a count of the number of operands it has that are not ready.
if (NodeId > 0) {
User->setNodeId(NodeId-1);
// If this was the last use it was waiting on, add it to the ready list.
if (NodeId-1 == ReadyToProcess)
Worklist.push_back(User);
continue;
}
// If this is an unreachable new node, then ignore it. If it ever becomes
// reachable by being used by a newly created node then it will be handled
// by AnalyzeNewNode.
if (NodeId == NewNode)
continue;
// Otherwise, this node is new: this is the first operand of it that
// became ready. Its new NodeId is the number of operands it has minus 1
// (as this node is now processed).
assert(NodeId == Unanalyzed && "Unknown node ID!");
User->setNodeId(User->getNumOperands() - 1);
// If the node only has a single operand, it is now ready.
if (User->getNumOperands() == 1)
Worklist.push_back(User);
}
}
/// Select instructions not customized! Used for
/// expanded, promoted and normal instructions
SDNode* MBlazeDAGToDAGISel::Select(SDNode *Node) {
unsigned Opcode = Node->getOpcode();
SDLoc dl(Node);
// If we have a custom node, we already have selected!
if (Node->isMachineOpcode())
return NULL;
///
// Instruction Selection not handled by the auto-generated
// tablegen selection should be handled here.
///
switch (Opcode) {
default: break;
// Get target GOT address.
case ISD::GLOBAL_OFFSET_TABLE:
return getGlobalBaseReg();
case ISD::FrameIndex: {
SDValue imm = CurDAG->getTargetConstant(0, MVT::i32);
int FI = dyn_cast<FrameIndexSDNode>(Node)->getIndex();
EVT VT = Node->getValueType(0);
SDValue TFI = CurDAG->getTargetFrameIndex(FI, VT);
unsigned Opc = MBlaze::ADDIK;
if (Node->hasOneUse())
return CurDAG->SelectNodeTo(Node, Opc, VT, TFI, imm);
return CurDAG->getMachineNode(Opc, dl, VT, TFI, imm);
}
/// Handle direct and indirect calls when using PIC. On PIC, when
/// GOT is smaller than about 64k (small code) the GA target is
/// loaded with only one instruction. Otherwise GA's target must
/// be loaded with 3 instructions.
case MBlazeISD::JmpLink: {
if (TM.getRelocationModel() == Reloc::PIC_) {
SDValue Chain = Node->getOperand(0);
SDValue Callee = Node->getOperand(1);
SDValue R20Reg = CurDAG->getRegister(MBlaze::R20, MVT::i32);
SDValue InFlag(0, 0);
if ((isa<GlobalAddressSDNode>(Callee)) ||
(isa<ExternalSymbolSDNode>(Callee)))
{
/// Direct call for global addresses and external symbols
SDValue GPReg = CurDAG->getRegister(MBlaze::R15, MVT::i32);
// Use load to get GOT target
SDValue Ops[] = { Callee, GPReg, Chain };
SDValue Load = SDValue(CurDAG->getMachineNode(MBlaze::LW, dl,
MVT::i32, MVT::Other, Ops), 0);
Chain = Load.getValue(1);
// Call target must be on T9
Chain = CurDAG->getCopyToReg(Chain, dl, R20Reg, Load, InFlag);
} else
/// Indirect call
Chain = CurDAG->getCopyToReg(Chain, dl, R20Reg, Callee, InFlag);
// Emit Jump and Link Register
SDNode *ResNode = CurDAG->getMachineNode(MBlaze::BRLID, dl, MVT::Other,
MVT::Glue, R20Reg, Chain);
Chain = SDValue(ResNode, 0);
InFlag = SDValue(ResNode, 1);
ReplaceUses(SDValue(Node, 0), Chain);
ReplaceUses(SDValue(Node, 1), InFlag);
return ResNode;
}
}
}
// Select the default instruction
SDNode *ResNode = SelectCode(Node);
DEBUG(errs() << "=> ");
if (ResNode == NULL || ResNode == Node)
DEBUG(Node->dump(CurDAG));
else
DEBUG(ResNode->dump(CurDAG));
DEBUG(errs() << "\n");
return ResNode;
}
// Select - Convert the specified operand from a target-independent to a
// target-specific node if it hasn't already been changed.
SDNode *IA64DAGToDAGISel::Select(SDValue Op) {
SDNode *N = Op.getNode();
if (N->isMachineOpcode())
return NULL; // Already selected.
DebugLoc dl = Op.getDebugLoc();
switch (N->getOpcode()) {
default:
break;
case IA64ISD::BRCALL: { // XXX: this is also a hack!
SDValue Chain = N->getOperand(0);
SDValue InFlag; // Null incoming flag value.
if(N->getNumOperands()==3) { // we have an incoming chain, callee and flag
InFlag = N->getOperand(2);
}
unsigned CallOpcode;
SDValue CallOperand;
// if we can call directly, do so
if (GlobalAddressSDNode *GASD =
dyn_cast<GlobalAddressSDNode>(N->getOperand(1))) {
CallOpcode = IA64::BRCALL_IPREL_GA;
CallOperand = CurDAG->getTargetGlobalAddress(GASD->getGlobal(), MVT::i64);
} else if (isa<ExternalSymbolSDNode>(N->getOperand(1))) {
// FIXME: we currently NEED this case for correctness, to avoid
// "non-pic code with imm reloc.n against dynamic symbol" errors
CallOpcode = IA64::BRCALL_IPREL_ES;
CallOperand = N->getOperand(1);
} else {
// otherwise we need to load the function descriptor,
// load the branch target (function)'s entry point and GP,
// branch (call) then restore the GP
SDValue FnDescriptor = N->getOperand(1);
// load the branch target's entry point [mem] and
// GP value [mem+8]
SDValue targetEntryPoint=
SDValue(CurDAG->getTargetNode(IA64::LD8, dl, MVT::i64, MVT::Other,
FnDescriptor, CurDAG->getEntryNode()), 0);
Chain = targetEntryPoint.getValue(1);
SDValue targetGPAddr=
SDValue(CurDAG->getTargetNode(IA64::ADDS, dl, MVT::i64,
FnDescriptor,
CurDAG->getConstant(8, MVT::i64)), 0);
Chain = targetGPAddr.getValue(1);
SDValue targetGP =
SDValue(CurDAG->getTargetNode(IA64::LD8, dl, MVT::i64,MVT::Other,
targetGPAddr, CurDAG->getEntryNode()), 0);
Chain = targetGP.getValue(1);
Chain = CurDAG->getCopyToReg(Chain, dl, IA64::r1, targetGP, InFlag);
InFlag = Chain.getValue(1);
Chain = CurDAG->getCopyToReg(Chain, dl, IA64::B6,
targetEntryPoint, InFlag); // FLAG these?
InFlag = Chain.getValue(1);
CallOperand = CurDAG->getRegister(IA64::B6, MVT::i64);
CallOpcode = IA64::BRCALL_INDIRECT;
}
// Finally, once everything is setup, emit the call itself
if (InFlag.getNode())
Chain = SDValue(CurDAG->getTargetNode(CallOpcode, dl, MVT::Other,
MVT::Flag, CallOperand, InFlag), 0);
else // there might be no arguments
Chain = SDValue(CurDAG->getTargetNode(CallOpcode, dl, MVT::Other,
MVT::Flag, CallOperand, Chain), 0);
InFlag = Chain.getValue(1);
std::vector<SDValue> CallResults;
CallResults.push_back(Chain);
CallResults.push_back(InFlag);
for (unsigned i = 0, e = CallResults.size(); i != e; ++i)
ReplaceUses(Op.getValue(i), CallResults[i]);
return NULL;
}
case IA64ISD::GETFD: {
SDValue Input = N->getOperand(0);
return CurDAG->getTargetNode(IA64::GETFD, dl, MVT::i64, Input);
}
case ISD::FDIV:
case ISD::SDIV:
case ISD::UDIV:
case ISD::SREM:
case ISD::UREM:
return SelectDIV(Op);
case ISD::TargetConstantFP: {
SDValue Chain = CurDAG->getEntryNode(); // this is a constant, so..
SDValue V;
ConstantFPSDNode* N2 = cast<ConstantFPSDNode>(N);
if (N2->getValueAPF().isPosZero()) {
V = CurDAG->getCopyFromReg(Chain, dl, IA64::F0, MVT::f64);
} else if (N2->isExactlyValue(N2->getValueType(0) == MVT::f32 ?
APFloat(+1.0f) : APFloat(+1.0))) {
V = CurDAG->getCopyFromReg(Chain, dl, IA64::F1, MVT::f64);
} else
assert(0 && "Unexpected FP constant!");
ReplaceUses(SDValue(N, 0), V);
return 0;
}
case ISD::FrameIndex: { // TODO: reduce creepyness
int FI = cast<FrameIndexSDNode>(N)->getIndex();
if (N->hasOneUse())
return CurDAG->SelectNodeTo(N, IA64::MOV, MVT::i64,
CurDAG->getTargetFrameIndex(FI, MVT::i64));
else
return CurDAG->getTargetNode(IA64::MOV, dl, MVT::i64,
CurDAG->getTargetFrameIndex(FI, MVT::i64));
}
case ISD::ConstantPool: { // TODO: nuke the constant pool
// (ia64 doesn't need one)
ConstantPoolSDNode *CP = cast<ConstantPoolSDNode>(N);
Constant *C = CP->getConstVal();
SDValue CPI = CurDAG->getTargetConstantPool(C, MVT::i64,
CP->getAlignment());
return CurDAG->getTargetNode(IA64::ADDL_GA, dl, MVT::i64, // ?
CurDAG->getRegister(IA64::r1, MVT::i64), CPI);
}
case ISD::GlobalAddress: {
GlobalValue *GV = cast<GlobalAddressSDNode>(N)->getGlobal();
SDValue GA = CurDAG->getTargetGlobalAddress(GV, MVT::i64);
SDValue Tmp =
SDValue(CurDAG->getTargetNode(IA64::ADDL_GA, dl, MVT::i64,
CurDAG->getRegister(IA64::r1,
MVT::i64), GA), 0);
return CurDAG->getTargetNode(IA64::LD8, dl, MVT::i64, MVT::Other, Tmp,
CurDAG->getEntryNode());
}
/* XXX
case ISD::ExternalSymbol: {
SDValue EA = CurDAG->getTargetExternalSymbol(
cast<ExternalSymbolSDNode>(N)->getSymbol(),
MVT::i64);
SDValue Tmp = CurDAG->getTargetNode(IA64::ADDL_EA, dl, MVT::i64,
CurDAG->getRegister(IA64::r1,
MVT::i64),
EA);
return CurDAG->getTargetNode(IA64::LD8, dl, MVT::i64, Tmp);
}
*/
case ISD::LOAD: { // FIXME: load -1, not 1, for bools?
LoadSDNode *LD = cast<LoadSDNode>(N);
SDValue Chain = LD->getChain();
SDValue Address = LD->getBasePtr();
MVT TypeBeingLoaded = LD->getMemoryVT();
unsigned Opc;
switch (TypeBeingLoaded.getSimpleVT()) {
default:
#ifndef NDEBUG
N->dump(CurDAG);
#endif
assert(0 && "Cannot load this type!");
case MVT::i1: { // this is a bool
Opc = IA64::LD1; // first we load a byte, then compare for != 0
if(N->getValueType(0) == MVT::i1) { // XXX: early exit!
return CurDAG->SelectNodeTo(N, IA64::CMPNE, MVT::i1, MVT::Other,
SDValue(CurDAG->getTargetNode(Opc, dl,
MVT::i64,
Address), 0),
CurDAG->getRegister(IA64::r0, MVT::i64),
Chain);
}
/* otherwise, we want to load a bool into something bigger: LD1
will do that for us, so we just fall through */
}
case MVT::i8:
Opc = IA64::LD1;
break;
case MVT::i16:
Opc = IA64::LD2;
break;
case MVT::i32:
Opc = IA64::LD4;
break;
case MVT::i64:
Opc = IA64::LD8;
break;
case MVT::f32:
Opc = IA64::LDF4;
break;
case MVT::f64:
Opc = IA64::LDF8;
break;
}
// TODO: comment this
return CurDAG->SelectNodeTo(N, Opc, N->getValueType(0), MVT::Other,
Address, Chain);
}
case ISD::STORE: {
StoreSDNode *ST = cast<StoreSDNode>(N);
SDValue Address = ST->getBasePtr();
SDValue Chain = ST->getChain();
unsigned Opc;
if (ISD::isNON_TRUNCStore(N)) {
switch (N->getOperand(1).getValueType().getSimpleVT()) {
default:
assert(0 && "unknown type in store");
case MVT::i1: { // this is a bool
Opc = IA64::ST1; // we store either 0 or 1 as a byte
// first load zero!
SDValue Initial = CurDAG->getCopyFromReg(Chain, dl, IA64::r0, MVT::i64);
Chain = Initial.getValue(1);
// then load 1 into the same reg iff the predicate to store is 1
SDValue Tmp = ST->getValue();
Tmp =
SDValue(CurDAG->getTargetNode(IA64::TPCADDS, dl, MVT::i64, Initial,
CurDAG->getTargetConstant(1,
MVT::i64),
Tmp), 0);
return CurDAG->SelectNodeTo(N, Opc, MVT::Other, Address, Tmp, Chain);
}
case MVT::i64:
Opc = IA64::ST8;
break;
case MVT::f64:
Opc = IA64::STF8;
break;
}
} else { // Truncating store
switch(ST->getMemoryVT().getSimpleVT()) {
default:
assert(0 && "unknown type in truncstore");
case MVT::i8:
Opc = IA64::ST1;
break;
case MVT::i16:
Opc = IA64::ST2;
break;
case MVT::i32:
Opc = IA64::ST4;
break;
case MVT::f32:
Opc = IA64::STF4;
break;
}
}
SDValue N1 = N->getOperand(1);
SDValue N2 = N->getOperand(2);
return CurDAG->SelectNodeTo(N, Opc, MVT::Other, N2, N1, Chain);
}
case ISD::BRCOND: {
SDValue Chain = N->getOperand(0);
SDValue CC = N->getOperand(1);
MachineBasicBlock *Dest =
cast<BasicBlockSDNode>(N->getOperand(2))->getBasicBlock();
//FIXME - we do NOT need long branches all the time
return CurDAG->SelectNodeTo(N, IA64::BRLCOND_NOTCALL, MVT::Other, CC,
CurDAG->getBasicBlock(Dest), Chain);
}
case ISD::CALLSEQ_START:
case ISD::CALLSEQ_END: {
int64_t Amt = cast<ConstantSDNode>(N->getOperand(1))->getZExtValue();
unsigned Opc = N->getOpcode() == ISD::CALLSEQ_START ?
IA64::ADJUSTCALLSTACKDOWN : IA64::ADJUSTCALLSTACKUP;
SDValue N0 = N->getOperand(0);
return CurDAG->SelectNodeTo(N, Opc, MVT::Other, getI64Imm(Amt), N0);
}
case ISD::BR:
// FIXME: we don't need long branches all the time!
SDValue N0 = N->getOperand(0);
return CurDAG->SelectNodeTo(N, IA64::BRL_NOTCALL, MVT::Other,
N->getOperand(1), N0);
}
return SelectCode(Op);
}
