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llvm-6502/lib/Target/XCore/XCoreISelLowering.cpp
Bill Wendling b4202b84d7 Update comments to make it clear that the function alignment is the Log2 of the 
bytes and not bytes.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@74624 91177308-0d34-0410-b5e6-96231b3b80d8
2009-07-01 18:50:55 +00:00

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//===-- XCoreISelLowering.cpp - XCore DAG Lowering Implementation ------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements the XCoreTargetLowering class.
//
//===----------------------------------------------------------------------===//
#define DEBUG_TYPE "xcore-lower"
#include "XCoreISelLowering.h"
#include "XCoreMachineFunctionInfo.h"
#include "XCore.h"
#include "XCoreTargetMachine.h"
#include "XCoreSubtarget.h"
#include "llvm/DerivedTypes.h"
#include "llvm/Function.h"
#include "llvm/Intrinsics.h"
#include "llvm/CallingConv.h"
#include "llvm/GlobalVariable.h"
#include "llvm/GlobalAlias.h"
#include "llvm/CodeGen/CallingConvLower.h"
#include "llvm/CodeGen/MachineFrameInfo.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/CodeGen/SelectionDAGISel.h"
#include "llvm/CodeGen/ValueTypes.h"
#include "llvm/Support/Debug.h"
#include "llvm/ADT/VectorExtras.h"
#include <queue>
#include <set>
using namespace llvm;
const char *XCoreTargetLowering::
getTargetNodeName(unsigned Opcode) const
{
switch (Opcode)
{
case XCoreISD::BL : return "XCoreISD::BL";
case XCoreISD::PCRelativeWrapper : return "XCoreISD::PCRelativeWrapper";
case XCoreISD::DPRelativeWrapper : return "XCoreISD::DPRelativeWrapper";
case XCoreISD::CPRelativeWrapper : return "XCoreISD::CPRelativeWrapper";
case XCoreISD::STWSP : return "XCoreISD::STWSP";
case XCoreISD::RETSP : return "XCoreISD::RETSP";
default : return NULL;
}
}
XCoreTargetLowering::XCoreTargetLowering(XCoreTargetMachine &XTM)
: TargetLowering(XTM),
TM(XTM),
Subtarget(*XTM.getSubtargetImpl()) {
// Set up the register classes.
addRegisterClass(MVT::i32, XCore::GRRegsRegisterClass);
// Compute derived properties from the register classes
computeRegisterProperties();
// Division is expensive
setIntDivIsCheap(false);
setShiftAmountType(MVT::i32);
// shl X, 32 == 0
setShiftAmountFlavor(Extend);
setStackPointerRegisterToSaveRestore(XCore::SP);
setSchedulingPreference(SchedulingForRegPressure);
// Use i32 for setcc operations results (slt, sgt, ...).
setBooleanContents(ZeroOrOneBooleanContent);
// XCore does not have the NodeTypes below.
setOperationAction(ISD::BR_CC, MVT::Other, Expand);
setOperationAction(ISD::SELECT_CC, MVT::i32, Custom);
setOperationAction(ISD::ADDC, MVT::i32, Expand);
setOperationAction(ISD::ADDE, MVT::i32, Expand);
setOperationAction(ISD::SUBC, MVT::i32, Expand);
setOperationAction(ISD::SUBE, MVT::i32, Expand);
// Stop the combiner recombining select and set_cc
setOperationAction(ISD::SELECT_CC, MVT::Other, Expand);
// 64bit
if (!Subtarget.isXS1A()) {
setOperationAction(ISD::ADD, MVT::i64, Custom);
setOperationAction(ISD::SUB, MVT::i64, Custom);
}
if (Subtarget.isXS1A()) {
setOperationAction(ISD::SMUL_LOHI, MVT::i32, Expand);
}
setOperationAction(ISD::MULHS, MVT::i32, Expand);
setOperationAction(ISD::MULHU, MVT::i32, Expand);
setOperationAction(ISD::SHL_PARTS, MVT::i32, Expand);
setOperationAction(ISD::SRA_PARTS, MVT::i32, Expand);
setOperationAction(ISD::SRL_PARTS, MVT::i32, Expand);
// Bit Manipulation
setOperationAction(ISD::CTPOP, MVT::i32, Expand);
setOperationAction(ISD::ROTL , MVT::i32, Expand);
setOperationAction(ISD::ROTR , MVT::i32, Expand);
setOperationAction(ISD::TRAP, MVT::Other, Legal);
// Expand jump tables for now
setOperationAction(ISD::BR_JT, MVT::Other, Expand);
setOperationAction(ISD::JumpTable, MVT::i32, Custom);
// RET must be custom lowered, to meet ABI requirements
setOperationAction(ISD::RET, MVT::Other, Custom);
setOperationAction(ISD::GlobalAddress, MVT::i32, Custom);
// Thread Local Storage
setOperationAction(ISD::GlobalTLSAddress, MVT::i32, Custom);
// Conversion of i64 -> double produces constantpool nodes
setOperationAction(ISD::ConstantPool, MVT::i32, Custom);
// Loads
setLoadExtAction(ISD::EXTLOAD, MVT::i1, Promote);
setLoadExtAction(ISD::ZEXTLOAD, MVT::i1, Promote);
setLoadExtAction(ISD::SEXTLOAD, MVT::i1, Promote);
setLoadExtAction(ISD::SEXTLOAD, MVT::i8, Expand);
setLoadExtAction(ISD::ZEXTLOAD, MVT::i16, Expand);
// Varargs
setOperationAction(ISD::VAEND, MVT::Other, Expand);
setOperationAction(ISD::VACOPY, MVT::Other, Expand);
setOperationAction(ISD::VAARG, MVT::Other, Custom);
setOperationAction(ISD::VASTART, MVT::Other, Custom);
// Dynamic stack
setOperationAction(ISD::STACKSAVE, MVT::Other, Expand);
setOperationAction(ISD::STACKRESTORE, MVT::Other, Expand);
setOperationAction(ISD::DYNAMIC_STACKALLOC, MVT::i32, Expand);
// Debug
setOperationAction(ISD::DBG_STOPPOINT, MVT::Other, Expand);
setOperationAction(ISD::DEBUG_LOC, MVT::Other, Expand);
}
SDValue XCoreTargetLowering::
LowerOperation(SDValue Op, SelectionDAG &DAG) {
switch (Op.getOpcode())
{
case ISD::CALL: return LowerCALL(Op, DAG);
case ISD::FORMAL_ARGUMENTS: return LowerFORMAL_ARGUMENTS(Op, DAG);
case ISD::RET: return LowerRET(Op, DAG);
case ISD::GlobalAddress: return LowerGlobalAddress(Op, DAG);
case ISD::GlobalTLSAddress: return LowerGlobalTLSAddress(Op, DAG);
case ISD::ConstantPool: return LowerConstantPool(Op, DAG);
case ISD::JumpTable: return LowerJumpTable(Op, DAG);
case ISD::SELECT_CC: return LowerSELECT_CC(Op, DAG);
case ISD::VAARG: return LowerVAARG(Op, DAG);
case ISD::VASTART: return LowerVASTART(Op, DAG);
// FIXME: Remove these when LegalizeDAGTypes lands.
case ISD::ADD:
case ISD::SUB: return ExpandADDSUB(Op.getNode(), DAG);
case ISD::FRAMEADDR: return LowerFRAMEADDR(Op, DAG);
default:
assert(0 && "unimplemented operand");
return SDValue();
}
}
/// ReplaceNodeResults - Replace the results of node with an illegal result
/// type with new values built out of custom code.
void XCoreTargetLowering::ReplaceNodeResults(SDNode *N,
SmallVectorImpl<SDValue>&Results,
SelectionDAG &DAG) {
switch (N->getOpcode()) {
default:
assert(0 && "Don't know how to custom expand this!");
return;
case ISD::ADD:
case ISD::SUB:
Results.push_back(ExpandADDSUB(N, DAG));
return;
}
}
/// getFunctionAlignment - Return the Log2 alignment of this function.
unsigned XCoreTargetLowering::
getFunctionAlignment(const Function *) const {
return 1;
}
//===----------------------------------------------------------------------===//
// Misc Lower Operation implementation
//===----------------------------------------------------------------------===//
SDValue XCoreTargetLowering::
LowerSELECT_CC(SDValue Op, SelectionDAG &DAG)
{
DebugLoc dl = Op.getDebugLoc();
SDValue Cond = DAG.getNode(ISD::SETCC, dl, MVT::i32, Op.getOperand(2),
Op.getOperand(3), Op.getOperand(4));
return DAG.getNode(ISD::SELECT, dl, MVT::i32, Cond, Op.getOperand(0),
Op.getOperand(1));
}
SDValue XCoreTargetLowering::
getGlobalAddressWrapper(SDValue GA, GlobalValue *GV, SelectionDAG &DAG)
{
// FIXME there is no actual debug info here
DebugLoc dl = GA.getDebugLoc();
if (isa<Function>(GV)) {
return DAG.getNode(XCoreISD::PCRelativeWrapper, dl, MVT::i32, GA);
} else if (!Subtarget.isXS1A()) {
const GlobalVariable *GVar = dyn_cast<GlobalVariable>(GV);
if (!GVar) {
// If GV is an alias then use the aliasee to determine constness
if (const GlobalAlias *GA = dyn_cast<GlobalAlias>(GV))
GVar = dyn_cast_or_null<GlobalVariable>(GA->resolveAliasedGlobal());
}
bool isConst = GVar && GVar->isConstant();
if (isConst) {
return DAG.getNode(XCoreISD::CPRelativeWrapper, dl, MVT::i32, GA);
}
}
return DAG.getNode(XCoreISD::DPRelativeWrapper, dl, MVT::i32, GA);
}
SDValue XCoreTargetLowering::
LowerGlobalAddress(SDValue Op, SelectionDAG &DAG)
{
GlobalValue *GV = cast<GlobalAddressSDNode>(Op)->getGlobal();
SDValue GA = DAG.getTargetGlobalAddress(GV, MVT::i32);
// If it's a debug information descriptor, don't mess with it.
if (DAG.isVerifiedDebugInfoDesc(Op))
return GA;
return getGlobalAddressWrapper(GA, GV, DAG);
}
static inline SDValue BuildGetId(SelectionDAG &DAG, DebugLoc dl) {
return DAG.getNode(ISD::INTRINSIC_WO_CHAIN, dl, MVT::i32,
DAG.getConstant(Intrinsic::xcore_getid, MVT::i32));
}
static inline bool isZeroLengthArray(const Type *Ty) {
const ArrayType *AT = dyn_cast_or_null<ArrayType>(Ty);
return AT && (AT->getNumElements() == 0);
}
SDValue XCoreTargetLowering::
LowerGlobalTLSAddress(SDValue Op, SelectionDAG &DAG)
{
// FIXME there isn't really debug info here
DebugLoc dl = Op.getDebugLoc();
// transform to label + getid() * size
GlobalValue *GV = cast<GlobalAddressSDNode>(Op)->getGlobal();
SDValue GA = DAG.getTargetGlobalAddress(GV, MVT::i32);
const GlobalVariable *GVar = dyn_cast<GlobalVariable>(GV);
if (!GVar) {
// If GV is an alias then use the aliasee to determine size
if (const GlobalAlias *GA = dyn_cast<GlobalAlias>(GV))
GVar = dyn_cast_or_null<GlobalVariable>(GA->resolveAliasedGlobal());
}
if (! GVar) {
assert(0 && "Thread local object not a GlobalVariable?");
return SDValue();
}
const Type *Ty = cast<PointerType>(GV->getType())->getElementType();
if (!Ty->isSized() || isZeroLengthArray(Ty)) {
cerr << "Size of thread local object " << GVar->getName()
<< " is unknown\n";
abort();
}
SDValue base = getGlobalAddressWrapper(GA, GV, DAG);
const TargetData *TD = TM.getTargetData();
unsigned Size = TD->getTypeAllocSize(Ty);
SDValue offset = DAG.getNode(ISD::MUL, dl, MVT::i32, BuildGetId(DAG, dl),
DAG.getConstant(Size, MVT::i32));
return DAG.getNode(ISD::ADD, dl, MVT::i32, base, offset);
}
SDValue XCoreTargetLowering::
LowerConstantPool(SDValue Op, SelectionDAG &DAG)
{
ConstantPoolSDNode *CP = cast<ConstantPoolSDNode>(Op);
// FIXME there isn't really debug info here
DebugLoc dl = CP->getDebugLoc();
if (Subtarget.isXS1A()) {
assert(0 && "Lowering of constant pool unimplemented");
return SDValue();
} else {
MVT PtrVT = Op.getValueType();
SDValue Res;
if (CP->isMachineConstantPoolEntry()) {
Res = DAG.getTargetConstantPool(CP->getMachineCPVal(), PtrVT,
CP->getAlignment());
} else {
Res = DAG.getTargetConstantPool(CP->getConstVal(), PtrVT,
CP->getAlignment());
}
return DAG.getNode(XCoreISD::CPRelativeWrapper, dl, MVT::i32, Res);
}
}
SDValue XCoreTargetLowering::
LowerJumpTable(SDValue Op, SelectionDAG &DAG)
{
// FIXME there isn't really debug info here
DebugLoc dl = Op.getDebugLoc();
MVT PtrVT = Op.getValueType();
JumpTableSDNode *JT = cast<JumpTableSDNode>(Op);
SDValue JTI = DAG.getTargetJumpTable(JT->getIndex(), PtrVT);
return DAG.getNode(XCoreISD::DPRelativeWrapper, dl, MVT::i32, JTI);
}
SDValue XCoreTargetLowering::
ExpandADDSUB(SDNode *N, SelectionDAG &DAG)
{
assert(N->getValueType(0) == MVT::i64 &&
(N->getOpcode() == ISD::ADD || N->getOpcode() == ISD::SUB) &&
"Unknown operand to lower!");
assert(!Subtarget.isXS1A() && "Cannot custom lower ADD/SUB on xs1a");
DebugLoc dl = N->getDebugLoc();
// Extract components
SDValue LHSL = DAG.getNode(ISD::EXTRACT_ELEMENT, dl, MVT::i32,
N->getOperand(0), DAG.getConstant(0, MVT::i32));
SDValue LHSH = DAG.getNode(ISD::EXTRACT_ELEMENT, dl, MVT::i32,
N->getOperand(0), DAG.getConstant(1, MVT::i32));
SDValue RHSL = DAG.getNode(ISD::EXTRACT_ELEMENT, dl, MVT::i32,
N->getOperand(1), DAG.getConstant(0, MVT::i32));
SDValue RHSH = DAG.getNode(ISD::EXTRACT_ELEMENT, dl, MVT::i32,
N->getOperand(1), DAG.getConstant(1, MVT::i32));
// Expand
unsigned Opcode = (N->getOpcode() == ISD::ADD) ? XCoreISD::LADD :
XCoreISD::LSUB;
SDValue Zero = DAG.getConstant(0, MVT::i32);
SDValue Carry = DAG.getNode(Opcode, dl, DAG.getVTList(MVT::i32, MVT::i32),
LHSL, RHSL, Zero);
SDValue Lo(Carry.getNode(), 1);
SDValue Ignored = DAG.getNode(Opcode, dl, DAG.getVTList(MVT::i32, MVT::i32),
LHSH, RHSH, Carry);
SDValue Hi(Ignored.getNode(), 1);
// Merge the pieces
return DAG.getNode(ISD::BUILD_PAIR, dl, MVT::i64, Lo, Hi);
}
SDValue XCoreTargetLowering::
LowerVAARG(SDValue Op, SelectionDAG &DAG)
{
assert(0 && "unimplemented");
// FIX Arguments passed by reference need a extra dereference.
SDNode *Node = Op.getNode();
DebugLoc dl = Node->getDebugLoc();
const Value *V = cast<SrcValueSDNode>(Node->getOperand(2))->getValue();
MVT VT = Node->getValueType(0);
SDValue VAList = DAG.getLoad(getPointerTy(), dl, Node->getOperand(0),
Node->getOperand(1), V, 0);
// Increment the pointer, VAList, to the next vararg
SDValue Tmp3 = DAG.getNode(ISD::ADD, dl, getPointerTy(), VAList,
DAG.getConstant(VT.getSizeInBits(),
getPointerTy()));
// Store the incremented VAList to the legalized pointer
Tmp3 = DAG.getStore(VAList.getValue(1), dl, Tmp3, Node->getOperand(1), V, 0);
// Load the actual argument out of the pointer VAList
return DAG.getLoad(VT, dl, Tmp3, VAList, NULL, 0);
}
SDValue XCoreTargetLowering::
LowerVASTART(SDValue Op, SelectionDAG &DAG)
{
DebugLoc dl = Op.getDebugLoc();
// vastart stores the address of the VarArgsFrameIndex slot into the
// memory location argument
MachineFunction &MF = DAG.getMachineFunction();
XCoreFunctionInfo *XFI = MF.getInfo<XCoreFunctionInfo>();
SDValue Addr = DAG.getFrameIndex(XFI->getVarArgsFrameIndex(), MVT::i32);
const Value *SV = cast<SrcValueSDNode>(Op.getOperand(2))->getValue();
return DAG.getStore(Op.getOperand(0), dl, Addr, Op.getOperand(1), SV, 0);
}
SDValue XCoreTargetLowering::LowerFRAMEADDR(SDValue Op, SelectionDAG &DAG) {
DebugLoc dl = Op.getDebugLoc();
// Depths > 0 not supported yet!
if (cast<ConstantSDNode>(Op.getOperand(0))->getZExtValue() > 0)
return SDValue();
MachineFunction &MF = DAG.getMachineFunction();
const TargetRegisterInfo *RegInfo = getTargetMachine().getRegisterInfo();
return DAG.getCopyFromReg(DAG.getEntryNode(), dl,
RegInfo->getFrameRegister(MF), MVT::i32);
}
//===----------------------------------------------------------------------===//
// Calling Convention Implementation
//
// The lower operations present on calling convention works on this order:
// LowerCALL (virt regs --> phys regs, virt regs --> stack)
// LowerFORMAL_ARGUMENTS (phys --> virt regs, stack --> virt regs)
// LowerRET (virt regs --> phys regs)
// LowerCALL (phys regs --> virt regs)
//
//===----------------------------------------------------------------------===//
#include "XCoreGenCallingConv.inc"
//===----------------------------------------------------------------------===//
// CALL Calling Convention Implementation
//===----------------------------------------------------------------------===//
/// XCore custom CALL implementation
SDValue XCoreTargetLowering::
LowerCALL(SDValue Op, SelectionDAG &DAG)
{
CallSDNode *TheCall = cast<CallSDNode>(Op.getNode());
unsigned CallingConv = TheCall->getCallingConv();
// For now, only CallingConv::C implemented
switch (CallingConv)
{
default:
assert(0 && "Unsupported calling convention");
case CallingConv::Fast:
case CallingConv::C:
return LowerCCCCallTo(Op, DAG, CallingConv);
}
}
/// LowerCCCCallTo - functions arguments are copied from virtual
/// regs to (physical regs)/(stack frame), CALLSEQ_START and
/// CALLSEQ_END are emitted.
/// TODO: isTailCall, sret.
SDValue XCoreTargetLowering::
LowerCCCCallTo(SDValue Op, SelectionDAG &DAG, unsigned CC)
{
CallSDNode *TheCall = cast<CallSDNode>(Op.getNode());
SDValue Chain = TheCall->getChain();
SDValue Callee = TheCall->getCallee();
bool isVarArg = TheCall->isVarArg();
DebugLoc dl = Op.getDebugLoc();
// Analyze operands of the call, assigning locations to each operand.
SmallVector<CCValAssign, 16> ArgLocs;
CCState CCInfo(CC, isVarArg, getTargetMachine(), ArgLocs);
// The ABI dictates there should be one stack slot available to the callee
// on function entry (for saving lr).
CCInfo.AllocateStack(4, 4);
CCInfo.AnalyzeCallOperands(TheCall, CC_XCore);
// Get a count of how many bytes are to be pushed on the stack.
unsigned NumBytes = CCInfo.getNextStackOffset();
Chain = DAG.getCALLSEQ_START(Chain,DAG.getConstant(NumBytes,
getPointerTy(), true));
SmallVector<std::pair<unsigned, SDValue>, 4> RegsToPass;
SmallVector<SDValue, 12> MemOpChains;
// Walk the register/memloc assignments, inserting copies/loads.
for (unsigned i = 0, e = ArgLocs.size(); i != e; ++i) {
CCValAssign &VA = ArgLocs[i];
// Arguments start after the 5 first operands of ISD::CALL
SDValue Arg = TheCall->getArg(i);
// Promote the value if needed.
switch (VA.getLocInfo()) {
default: assert(0 && "Unknown loc info!");
case CCValAssign::Full: break;
case CCValAssign::SExt:
Arg = DAG.getNode(ISD::SIGN_EXTEND, dl, VA.getLocVT(), Arg);
break;
case CCValAssign::ZExt:
Arg = DAG.getNode(ISD::ZERO_EXTEND, dl, VA.getLocVT(), Arg);
break;
case CCValAssign::AExt:
Arg = DAG.getNode(ISD::ANY_EXTEND, dl, VA.getLocVT(), Arg);
break;
}
// Arguments that can be passed on register must be kept at
// RegsToPass vector
if (VA.isRegLoc()) {
RegsToPass.push_back(std::make_pair(VA.getLocReg(), Arg));
} else {
assert(VA.isMemLoc());
int Offset = VA.getLocMemOffset();
MemOpChains.push_back(DAG.getNode(XCoreISD::STWSP, dl, MVT::Other,
Chain, Arg,
DAG.getConstant(Offset/4, MVT::i32)));
}
}
// Transform all store nodes into one single node because
// all store nodes are independent of each other.
if (!MemOpChains.empty())
Chain = DAG.getNode(ISD::TokenFactor, dl, MVT::Other,
&MemOpChains[0], MemOpChains.size());
// Build a sequence of copy-to-reg nodes chained together with token
// chain and flag operands which copy the outgoing args into registers.
// The InFlag in necessary since all emited instructions must be
// stuck together.
SDValue InFlag;
for (unsigned i = 0, e = RegsToPass.size(); i != e; ++i) {
Chain = DAG.getCopyToReg(Chain, dl, RegsToPass[i].first,
RegsToPass[i].second, InFlag);
InFlag = Chain.getValue(1);
}
// If the callee is a GlobalAddress node (quite common, every direct call is)
// turn it into a TargetGlobalAddress node so that legalize doesn't hack it.
// Likewise ExternalSymbol -> TargetExternalSymbol.
if (GlobalAddressSDNode *G = dyn_cast<GlobalAddressSDNode>(Callee))
Callee = DAG.getTargetGlobalAddress(G->getGlobal(), MVT::i32);
else if (ExternalSymbolSDNode *E = dyn_cast<ExternalSymbolSDNode>(Callee))
Callee = DAG.getTargetExternalSymbol(E->getSymbol(), MVT::i32);
// XCoreBranchLink = #chain, #target_address, #opt_in_flags...
// = Chain, Callee, Reg#1, Reg#2, ...
//
// Returns a chain & a flag for retval copy to use.
SDVTList NodeTys = DAG.getVTList(MVT::Other, MVT::Flag);
SmallVector<SDValue, 8> Ops;
Ops.push_back(Chain);
Ops.push_back(Callee);
// Add argument registers to the end of the list so that they are
// known live into the call.
for (unsigned i = 0, e = RegsToPass.size(); i != e; ++i)
Ops.push_back(DAG.getRegister(RegsToPass[i].first,
RegsToPass[i].second.getValueType()));
if (InFlag.getNode())
Ops.push_back(InFlag);
Chain = DAG.getNode(XCoreISD::BL, dl, NodeTys, &Ops[0], Ops.size());
InFlag = Chain.getValue(1);
// Create the CALLSEQ_END node.
Chain = DAG.getCALLSEQ_END(Chain,
DAG.getConstant(NumBytes, getPointerTy(), true),
DAG.getConstant(0, getPointerTy(), true),
InFlag);
InFlag = Chain.getValue(1);
// Handle result values, copying them out of physregs into vregs that we
// return.
return SDValue(LowerCallResult(Chain, InFlag, TheCall, CC, DAG),
Op.getResNo());
}
/// LowerCallResult - Lower the result values of an ISD::CALL into the
/// appropriate copies out of appropriate physical registers. This assumes that
/// Chain/InFlag are the input chain/flag to use, and that TheCall is the call
/// being lowered. Returns a SDNode with the same number of values as the
/// ISD::CALL.
SDNode *XCoreTargetLowering::
LowerCallResult(SDValue Chain, SDValue InFlag, CallSDNode *TheCall,
unsigned CallingConv, SelectionDAG &DAG) {
bool isVarArg = TheCall->isVarArg();
DebugLoc dl = TheCall->getDebugLoc();
// Assign locations to each value returned by this call.
SmallVector<CCValAssign, 16> RVLocs;
CCState CCInfo(CallingConv, isVarArg, getTargetMachine(), RVLocs);
CCInfo.AnalyzeCallResult(TheCall, RetCC_XCore);
SmallVector<SDValue, 8> ResultVals;
// Copy all of the result registers out of their specified physreg.
for (unsigned i = 0; i != RVLocs.size(); ++i) {
Chain = DAG.getCopyFromReg(Chain, dl, RVLocs[i].getLocReg(),
RVLocs[i].getValVT(), InFlag).getValue(1);
InFlag = Chain.getValue(2);
ResultVals.push_back(Chain.getValue(0));
}
ResultVals.push_back(Chain);
// Merge everything together with a MERGE_VALUES node.
return DAG.getNode(ISD::MERGE_VALUES, dl, TheCall->getVTList(),
&ResultVals[0], ResultVals.size()).getNode();
}
//===----------------------------------------------------------------------===//
// FORMAL_ARGUMENTS Calling Convention Implementation
//===----------------------------------------------------------------------===//
/// XCore custom FORMAL_ARGUMENTS implementation
SDValue XCoreTargetLowering::
LowerFORMAL_ARGUMENTS(SDValue Op, SelectionDAG &DAG)
{
unsigned CC = cast<ConstantSDNode>(Op.getOperand(1))->getZExtValue();
switch(CC)
{
default:
assert(0 && "Unsupported calling convention");
case CallingConv::C:
case CallingConv::Fast:
return LowerCCCArguments(Op, DAG);
}
}
/// LowerCCCArguments - transform physical registers into
/// virtual registers and generate load operations for
/// arguments places on the stack.
/// TODO: sret
SDValue XCoreTargetLowering::
LowerCCCArguments(SDValue Op, SelectionDAG &DAG)
{
MachineFunction &MF = DAG.getMachineFunction();
MachineFrameInfo *MFI = MF.getFrameInfo();
MachineRegisterInfo &RegInfo = MF.getRegInfo();
SDValue Root = Op.getOperand(0);
bool isVarArg = cast<ConstantSDNode>(Op.getOperand(2))->getZExtValue() != 0;
unsigned CC = MF.getFunction()->getCallingConv();
DebugLoc dl = Op.getDebugLoc();
// Assign locations to all of the incoming arguments.
SmallVector<CCValAssign, 16> ArgLocs;
CCState CCInfo(CC, isVarArg, getTargetMachine(), ArgLocs);
CCInfo.AnalyzeFormalArguments(Op.getNode(), CC_XCore);
unsigned StackSlotSize = XCoreFrameInfo::stackSlotSize();
SmallVector<SDValue, 16> ArgValues;
unsigned LRSaveSize = StackSlotSize;
for (unsigned i = 0, e = ArgLocs.size(); i != e; ++i) {
CCValAssign &VA = ArgLocs[i];
if (VA.isRegLoc()) {
// Arguments passed in registers
MVT RegVT = VA.getLocVT();
switch (RegVT.getSimpleVT()) {
default:
cerr << "LowerFORMAL_ARGUMENTS Unhandled argument type: "
<< RegVT.getSimpleVT()
<< "\n";
abort();
case MVT::i32:
unsigned VReg = RegInfo.createVirtualRegister(
XCore::GRRegsRegisterClass);
RegInfo.addLiveIn(VA.getLocReg(), VReg);
ArgValues.push_back(DAG.getCopyFromReg(Root, dl, VReg, RegVT));
}
} else {
// sanity check
assert(VA.isMemLoc());
// Load the argument to a virtual register
unsigned ObjSize = VA.getLocVT().getSizeInBits()/8;
if (ObjSize > StackSlotSize) {
cerr << "LowerFORMAL_ARGUMENTS Unhandled argument type: "
<< VA.getLocVT().getSimpleVT()
<< "\n";
}
// Create the frame index object for this incoming parameter...
int FI = MFI->CreateFixedObject(ObjSize,
LRSaveSize + VA.getLocMemOffset());
// Create the SelectionDAG nodes corresponding to a load
//from this parameter
SDValue FIN = DAG.getFrameIndex(FI, MVT::i32);
ArgValues.push_back(DAG.getLoad(VA.getLocVT(), dl, Root, FIN, NULL, 0));
}
}
if (isVarArg) {
/* Argument registers */
static const unsigned ArgRegs[] = {
XCore::R0, XCore::R1, XCore::R2, XCore::R3
};
XCoreFunctionInfo *XFI = MF.getInfo<XCoreFunctionInfo>();
unsigned FirstVAReg = CCInfo.getFirstUnallocated(ArgRegs,
array_lengthof(ArgRegs));
if (FirstVAReg < array_lengthof(ArgRegs)) {
SmallVector<SDValue, 4> MemOps;
int offset = 0;
// Save remaining registers, storing higher register numbers at a higher
// address
for (unsigned i = array_lengthof(ArgRegs) - 1; i >= FirstVAReg; --i) {
// Create a stack slot
int FI = MFI->CreateFixedObject(4, offset);
if (i == FirstVAReg) {
XFI->setVarArgsFrameIndex(FI);
}
offset -= StackSlotSize;
SDValue FIN = DAG.getFrameIndex(FI, MVT::i32);
// Move argument from phys reg -> virt reg
unsigned VReg = RegInfo.createVirtualRegister(
XCore::GRRegsRegisterClass);
RegInfo.addLiveIn(ArgRegs[i], VReg);
SDValue Val = DAG.getCopyFromReg(Root, dl, VReg, MVT::i32);
// Move argument from virt reg -> stack
SDValue Store = DAG.getStore(Val.getValue(1), dl, Val, FIN, NULL, 0);
MemOps.push_back(Store);
}
if (!MemOps.empty())
Root = DAG.getNode(ISD::TokenFactor, dl, MVT::Other,
&MemOps[0], MemOps.size());
} else {
// This will point to the next argument passed via stack.
XFI->setVarArgsFrameIndex(
MFI->CreateFixedObject(4, LRSaveSize + CCInfo.getNextStackOffset()));
}
}
ArgValues.push_back(Root);
// Return the new list of results.
std::vector<MVT> RetVT(Op.getNode()->value_begin(),
Op.getNode()->value_end());
return DAG.getNode(ISD::MERGE_VALUES, dl, RetVT,
&ArgValues[0], ArgValues.size());
}
//===----------------------------------------------------------------------===//
// Return Value Calling Convention Implementation
//===----------------------------------------------------------------------===//
SDValue XCoreTargetLowering::
LowerRET(SDValue Op, SelectionDAG &DAG)
{
// CCValAssign - represent the assignment of
// the return value to a location
SmallVector<CCValAssign, 16> RVLocs;
unsigned CC = DAG.getMachineFunction().getFunction()->getCallingConv();
bool isVarArg = DAG.getMachineFunction().getFunction()->isVarArg();
DebugLoc dl = Op.getDebugLoc();
// CCState - Info about the registers and stack slot.
CCState CCInfo(CC, isVarArg, getTargetMachine(), RVLocs);
// Analize return values of ISD::RET
CCInfo.AnalyzeReturn(Op.getNode(), RetCC_XCore);
// If this is the first return lowered for this function, add
// the regs to the liveout set for the function.
if (DAG.getMachineFunction().getRegInfo().liveout_empty()) {
for (unsigned i = 0; i != RVLocs.size(); ++i)
if (RVLocs[i].isRegLoc())
DAG.getMachineFunction().getRegInfo().addLiveOut(RVLocs[i].getLocReg());
}
// The chain is always operand #0
SDValue Chain = Op.getOperand(0);
SDValue Flag;
// Copy the result values into the output registers.
for (unsigned i = 0; i != RVLocs.size(); ++i) {
CCValAssign &VA = RVLocs[i];
assert(VA.isRegLoc() && "Can only return in registers!");
// ISD::RET => ret chain, (regnum1,val1), ...
// So i*2+1 index only the regnums
Chain = DAG.getCopyToReg(Chain, dl, VA.getLocReg(),
Op.getOperand(i*2+1), Flag);
// guarantee that all emitted copies are
// stuck together, avoiding something bad
Flag = Chain.getValue(1);
}
// Return on XCore is always a "retsp 0"
if (Flag.getNode())
return DAG.getNode(XCoreISD::RETSP, dl, MVT::Other,
Chain, DAG.getConstant(0, MVT::i32), Flag);
else // Return Void
return DAG.getNode(XCoreISD::RETSP, dl, MVT::Other,
Chain, DAG.getConstant(0, MVT::i32));
}
//===----------------------------------------------------------------------===//
// Other Lowering Code
//===----------------------------------------------------------------------===//
MachineBasicBlock *
XCoreTargetLowering::EmitInstrWithCustomInserter(MachineInstr *MI,
MachineBasicBlock *BB) const {
const TargetInstrInfo &TII = *getTargetMachine().getInstrInfo();
DebugLoc dl = MI->getDebugLoc();
assert((MI->getOpcode() == XCore::SELECT_CC) &&
"Unexpected instr type to insert");
// To "insert" a SELECT_CC instruction, we actually have to insert the diamond
// control-flow pattern. The incoming instruction knows the destination vreg
// to set, the condition code register to branch on, the true/false values to
// select between, and a branch opcode to use.
const BasicBlock *LLVM_BB = BB->getBasicBlock();
MachineFunction::iterator It = BB;
++It;
// thisMBB:
// ...
// TrueVal = ...
// cmpTY ccX, r1, r2
// bCC copy1MBB
// fallthrough --> copy0MBB
MachineBasicBlock *thisMBB = BB;
MachineFunction *F = BB->getParent();
MachineBasicBlock *copy0MBB = F->CreateMachineBasicBlock(LLVM_BB);
MachineBasicBlock *sinkMBB = F->CreateMachineBasicBlock(LLVM_BB);
BuildMI(BB, dl, TII.get(XCore::BRFT_lru6))
.addReg(MI->getOperand(1).getReg()).addMBB(sinkMBB);
F->insert(It, copy0MBB);
F->insert(It, sinkMBB);
// Update machine-CFG edges by transferring all successors of the current
// block to the new block which will contain the Phi node for the select.
sinkMBB->transferSuccessors(BB);
// Next, add the true and fallthrough blocks as its successors.
BB->addSuccessor(copy0MBB);
BB->addSuccessor(sinkMBB);
// copy0MBB:
// %FalseValue = ...
// # fallthrough to sinkMBB
BB = copy0MBB;
// Update machine-CFG edges
BB->addSuccessor(sinkMBB);
// sinkMBB:
// %Result = phi [ %FalseValue, copy0MBB ], [ %TrueValue, thisMBB ]
// ...
BB = sinkMBB;
BuildMI(BB, dl, TII.get(XCore::PHI), MI->getOperand(0).getReg())
.addReg(MI->getOperand(3).getReg()).addMBB(copy0MBB)
.addReg(MI->getOperand(2).getReg()).addMBB(thisMBB);
F->DeleteMachineInstr(MI); // The pseudo instruction is gone now.
return BB;
}
//===----------------------------------------------------------------------===//
// Addressing mode description hooks
//===----------------------------------------------------------------------===//
static inline bool isImmUs(int64_t val)
{
return (val >= 0 && val <= 11);
}
static inline bool isImmUs2(int64_t val)
{
return (val%2 == 0 && isImmUs(val/2));
}
static inline bool isImmUs4(int64_t val)
{
return (val%4 == 0 && isImmUs(val/4));
}
/// isLegalAddressingMode - Return true if the addressing mode represented
/// by AM is legal for this target, for a load/store of the specified type.
bool
XCoreTargetLowering::isLegalAddressingMode(const AddrMode &AM,
const Type *Ty) const {
MVT VT = getValueType(Ty, true);
// Get expected value type after legalization
switch (VT.getSimpleVT()) {
// Legal load / stores
case MVT::i8:
case MVT::i16:
case MVT::i32:
break;
// Expand i1 -> i8
case MVT::i1:
VT = MVT::i8;
break;
// Everything else is lowered to words
default:
VT = MVT::i32;
break;
}
if (AM.BaseGV) {
return VT == MVT::i32 && !AM.HasBaseReg && AM.Scale == 0 &&
AM.BaseOffs%4 == 0;
}
switch (VT.getSimpleVT()) {
default:
return false;
case MVT::i8:
// reg + imm
if (AM.Scale == 0) {
return isImmUs(AM.BaseOffs);
}
return AM.Scale == 1 && AM.BaseOffs == 0;
case MVT::i16:
// reg + imm
if (AM.Scale == 0) {
return isImmUs2(AM.BaseOffs);
}
return AM.Scale == 2 && AM.BaseOffs == 0;
case MVT::i32:
// reg + imm
if (AM.Scale == 0) {
return isImmUs4(AM.BaseOffs);
}
// reg + reg<<2
return AM.Scale == 4 && AM.BaseOffs == 0;
}
return false;
}
//===----------------------------------------------------------------------===//
// XCore Inline Assembly Support
//===----------------------------------------------------------------------===//
std::vector<unsigned> XCoreTargetLowering::
getRegClassForInlineAsmConstraint(const std::string &Constraint,
MVT VT) const
{
if (Constraint.size() != 1)
return std::vector<unsigned>();
switch (Constraint[0]) {
default : break;
case 'r':
return make_vector<unsigned>(XCore::R0, XCore::R1, XCore::R2,
XCore::R3, XCore::R4, XCore::R5,
XCore::R6, XCore::R7, XCore::R8,
XCore::R9, XCore::R10, XCore::R11, 0);
break;
}
return std::vector<unsigned>();
}
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