//------------------------------------------------------------------------
// ContainCheckIndir: Determine whether operands of an indir should be contained.
//
// Arguments:
// indirNode - The indirection node of interest
//
// Notes:
// This is called for both store and load indirections.
//
// Return Value:
// None.
//
void Lowering::ContainCheckIndir(GenTreeIndir* indirNode)
{
// If this is the rhs of a block copy it will be handled when we handle the store.
if (indirNode->TypeGet() == TYP_STRUCT)
{
return;
}
#ifdef FEATURE_SIMD
// If indirTree is of TYP_SIMD12, don't mark addr as contained
// so that it always get computed to a register. This would
// mean codegen side logic doesn't need to handle all possible
// addr expressions that could be contained.
//
// TODO-ARM64-CQ: handle other addr mode expressions that could be marked
// as contained.
if (indirNode->TypeGet() == TYP_SIMD12)
{
return;
}
#endif // FEATURE_SIMD
GenTree* addr = indirNode->Addr();
bool makeContained = true;
if ((addr->OperGet() == GT_LEA) && IsSafeToContainMem(indirNode, addr))
{
GenTreeAddrMode* lea = addr->AsAddrMode();
GenTree* base = lea->Base();
GenTree* index = lea->Index();
int cns = lea->Offset();
#ifdef _TARGET_ARM_
// ARM floating-point load/store doesn't support a form similar to integer
// ldr Rdst, [Rbase + Roffset] with offset in a register. The only supported
// form is vldr Rdst, [Rbase + imm] with a more limited constraint on the imm.
if (lea->HasIndex() || !emitter::emitIns_valid_imm_for_vldst_offset(cns))
{
if (indirNode->OperGet() == GT_STOREIND)
{
if (varTypeIsFloating(indirNode->AsStoreInd()->Data()))
{
makeContained = false;
}
}
else if (indirNode->OperGet() == GT_IND)
{
if (varTypeIsFloating(indirNode))
{
makeContained = false;
}
}
}
#endif
if (makeContained)
{
MakeSrcContained(indirNode, addr);
}
}
}
//------------------------------------------------------------------------
// ContainCheckIndir: Determine whether operands of an indir should be contained.
//
// Arguments:
// indirNode - The indirection node of interest
//
// Notes:
// This is called for both store and load indirections.
//
// Return Value:
// None.
//
void Lowering::ContainCheckIndir(GenTreeIndir* indirNode)
{
// If this is the rhs of a block copy it will be handled when we handle the store.
if (indirNode->TypeGet() == TYP_STRUCT)
{
return;
}
GenTree* addr = indirNode->Addr();
bool makeContained = true;
if ((addr->OperGet() == GT_LEA) && IsSafeToContainMem(indirNode, addr))
{
GenTreeAddrMode* lea = addr->AsAddrMode();
GenTree* base = lea->Base();
GenTree* index = lea->Index();
int cns = lea->Offset();
#ifdef _TARGET_ARM_
// ARM floating-point load/store doesn't support a form similar to integer
// ldr Rdst, [Rbase + Roffset] with offset in a register. The only supported
// form is vldr Rdst, [Rbase + imm] with a more limited constraint on the imm.
if (lea->HasIndex() || !emitter::emitIns_valid_imm_for_vldst_offset(cns))
{
if (indirNode->OperGet() == GT_STOREIND)
{
if (varTypeIsFloating(indirNode->AsStoreInd()->Data()))
{
makeContained = false;
}
}
else if (indirNode->OperGet() == GT_IND)
{
if (varTypeIsFloating(indirNode))
{
makeContained = false;
}
}
}
#endif
if (makeContained)
{
MakeSrcContained(indirNode, addr);
}
}
}
//------------------------------------------------------------------------
// BuildNode: Build the RefPositions for for a node
//
// Arguments:
// treeNode - the node of interest
//
// Return Value:
// The number of sources consumed by this node.
//
// Notes:
// Preconditions:
// LSRA Has been initialized.
//
// Postconditions:
// RefPositions have been built for all the register defs and uses required
// for this node.
//
int LinearScan::BuildNode(GenTree* tree)
{
assert(!tree->isContained());
Interval* prefSrcInterval = nullptr;
int srcCount;
int dstCount = 0;
regMaskTP dstCandidates = RBM_NONE;
regMaskTP killMask = RBM_NONE;
bool isLocalDefUse = false;
// Reset the build-related members of LinearScan.
clearBuildState();
RegisterType registerType = TypeGet(tree);
// Set the default dstCount. This may be modified below.
if (tree->IsValue())
{
dstCount = 1;
if (tree->IsUnusedValue())
{
isLocalDefUse = true;
}
}
else
{
dstCount = 0;
}
switch (tree->OperGet())
{
default:
srcCount = BuildSimple(tree);
break;
case GT_LCL_VAR:
case GT_LCL_FLD:
{
// We handle tracked variables differently from non-tracked ones. If it is tracked,
// we will simply add a use of the tracked variable at its parent/consumer.
// Otherwise, for a use we need to actually add the appropriate references for loading
// or storing the variable.
//
// A tracked variable won't actually get used until the appropriate ancestor tree node
// is processed, unless this is marked "isLocalDefUse" because it is a stack-based argument
// to a call or an orphaned dead node.
//
LclVarDsc* const varDsc = &compiler->lvaTable[tree->AsLclVarCommon()->gtLclNum];
if (isCandidateVar(varDsc))
{
INDEBUG(dumpNodeInfo(tree, dstCandidates, 0, 1));
return 0;
}
srcCount = 0;
#ifdef FEATURE_SIMD
// Need an additional register to read upper 4 bytes of Vector3.
if (tree->TypeGet() == TYP_SIMD12)
{
// We need an internal register different from targetReg in which 'tree' produces its result
// because both targetReg and internal reg will be in use at the same time.
buildInternalFloatRegisterDefForNode(tree, allSIMDRegs());
setInternalRegsDelayFree = true;
buildInternalRegisterUses();
}
#endif
BuildDef(tree);
}
break;
case GT_STORE_LCL_FLD:
case GT_STORE_LCL_VAR:
srcCount = 1;
assert(dstCount == 0);
srcCount = BuildStoreLoc(tree->AsLclVarCommon());
break;
case GT_FIELD_LIST:
// These should always be contained. We don't correctly allocate or
// generate code for a non-contained GT_FIELD_LIST.
noway_assert(!"Non-contained GT_FIELD_LIST");
srcCount = 0;
break;
case GT_LIST:
case GT_ARGPLACE:
case GT_NO_OP:
case GT_START_NONGC:
case GT_PROF_HOOK:
srcCount = 0;
assert(dstCount == 0);
break;
case GT_START_PREEMPTGC:
// This kills GC refs in callee save regs
srcCount = 0;
assert(dstCount == 0);
BuildDefsWithKills(tree, 0, RBM_NONE, RBM_NONE);
break;
case GT_CNS_DBL:
{
GenTreeDblCon* dblConst = tree->AsDblCon();
double constValue = dblConst->gtDblCon.gtDconVal;
if (emitter::emitIns_valid_imm_for_fmov(constValue))
{
// Directly encode constant to instructions.
}
else
{
// Reserve int to load constant from memory (IF_LARGELDC)
buildInternalIntRegisterDefForNode(tree);
buildInternalRegisterUses();
}
}
__fallthrough;
case GT_CNS_INT:
{
srcCount = 0;
assert(dstCount == 1);
RefPosition* def = BuildDef(tree);
def->getInterval()->isConstant = true;
}
break;
case GT_BOX:
case GT_COMMA:
case GT_QMARK:
case GT_COLON:
srcCount = 0;
assert(dstCount == 0);
unreached();
break;
case GT_RETURN:
srcCount = BuildReturn(tree);
break;
case GT_RETFILT:
assert(dstCount == 0);
if (tree->TypeGet() == TYP_VOID)
{
srcCount = 0;
}
else
{
assert(tree->TypeGet() == TYP_INT);
srcCount = 1;
BuildUse(tree->gtGetOp1(), RBM_INTRET);
}
break;
case GT_NOP:
// A GT_NOP is either a passthrough (if it is void, or if it has
// a child), but must be considered to produce a dummy value if it
// has a type but no child.
srcCount = 0;
if (tree->TypeGet() != TYP_VOID && tree->gtGetOp1() == nullptr)
{
assert(dstCount == 1);
BuildDef(tree);
}
else
{
assert(dstCount == 0);
}
break;
case GT_JTRUE:
srcCount = 0;
assert(dstCount == 0);
break;
case GT_JMP:
srcCount = 0;
assert(dstCount == 0);
break;
case GT_SWITCH:
// This should never occur since switch nodes must not be visible at this
// point in the JIT.
srcCount = 0;
noway_assert(!"Switch must be lowered at this point");
break;
case GT_JMPTABLE:
srcCount = 0;
assert(dstCount == 1);
BuildDef(tree);
break;
case GT_SWITCH_TABLE:
buildInternalIntRegisterDefForNode(tree);
srcCount = BuildBinaryUses(tree->AsOp());
assert(dstCount == 0);
break;
case GT_ASG:
noway_assert(!"We should never hit any assignment operator in lowering");
srcCount = 0;
break;
case GT_ADD:
case GT_SUB:
if (varTypeIsFloating(tree->TypeGet()))
{
// overflow operations aren't supported on float/double types.
assert(!tree->gtOverflow());
// No implicit conversions at this stage as the expectation is that
// everything is made explicit by adding casts.
assert(tree->gtGetOp1()->TypeGet() == tree->gtGetOp2()->TypeGet());
}
__fallthrough;
case GT_AND:
case GT_OR:
case GT_XOR:
case GT_LSH:
case GT_RSH:
case GT_RSZ:
case GT_ROR:
srcCount = BuildBinaryUses(tree->AsOp());
assert(dstCount == 1);
BuildDef(tree);
break;
case GT_RETURNTRAP:
// this just turns into a compare of its child with an int
// + a conditional call
BuildUse(tree->gtGetOp1());
srcCount = 1;
assert(dstCount == 0);
killMask = compiler->compHelperCallKillSet(CORINFO_HELP_STOP_FOR_GC);
BuildDefsWithKills(tree, 0, RBM_NONE, killMask);
break;
case GT_MOD:
case GT_UMOD:
NYI_IF(varTypeIsFloating(tree->TypeGet()), "FP Remainder in ARM64");
assert(!"Shouldn't see an integer typed GT_MOD node in ARM64");
srcCount = 0;
break;
case GT_MUL:
if (tree->gtOverflow())
{
// Need a register different from target reg to check for overflow.
buildInternalIntRegisterDefForNode(tree);
setInternalRegsDelayFree = true;
}
__fallthrough;
case GT_DIV:
case GT_MULHI:
case GT_UDIV:
{
srcCount = BuildBinaryUses(tree->AsOp());
buildInternalRegisterUses();
assert(dstCount == 1);
BuildDef(tree);
}
break;
case GT_INTRINSIC:
{
noway_assert((tree->gtIntrinsic.gtIntrinsicId == CORINFO_INTRINSIC_Abs) ||
(tree->gtIntrinsic.gtIntrinsicId == CORINFO_INTRINSIC_Ceiling) ||
(tree->gtIntrinsic.gtIntrinsicId == CORINFO_INTRINSIC_Floor) ||
(tree->gtIntrinsic.gtIntrinsicId == CORINFO_INTRINSIC_Round) ||
(tree->gtIntrinsic.gtIntrinsicId == CORINFO_INTRINSIC_Sqrt));
// Both operand and its result must be of the same floating point type.
GenTree* op1 = tree->gtGetOp1();
assert(varTypeIsFloating(op1));
assert(op1->TypeGet() == tree->TypeGet());
BuildUse(op1);
srcCount = 1;
assert(dstCount == 1);
BuildDef(tree);
}
break;
#ifdef FEATURE_SIMD
case GT_SIMD:
srcCount = BuildSIMD(tree->AsSIMD());
break;
#endif // FEATURE_SIMD
#ifdef FEATURE_HW_INTRINSICS
case GT_HWIntrinsic:
srcCount = BuildHWIntrinsic(tree->AsHWIntrinsic());
break;
#endif // FEATURE_HW_INTRINSICS
case GT_CAST:
assert(dstCount == 1);
srcCount = BuildCast(tree->AsCast());
break;
case GT_NEG:
case GT_NOT:
BuildUse(tree->gtGetOp1());
srcCount = 1;
assert(dstCount == 1);
BuildDef(tree);
break;
case GT_EQ:
case GT_NE:
case GT_LT:
case GT_LE:
case GT_GE:
case GT_GT:
case GT_TEST_EQ:
case GT_TEST_NE:
case GT_JCMP:
srcCount = BuildCmp(tree);
break;
case GT_CKFINITE:
srcCount = 1;
assert(dstCount == 1);
buildInternalIntRegisterDefForNode(tree);
BuildUse(tree->gtGetOp1());
BuildDef(tree);
buildInternalRegisterUses();
break;
case GT_CMPXCHG:
{
GenTreeCmpXchg* cmpXchgNode = tree->AsCmpXchg();
srcCount = cmpXchgNode->gtOpComparand->isContained() ? 2 : 3;
assert(dstCount == 1);
if (!compiler->compSupports(InstructionSet_Atomics))
{
// For ARMv8 exclusives requires a single internal register
buildInternalIntRegisterDefForNode(tree);
}
// For ARMv8 exclusives the lifetime of the addr and data must be extended because
// it may be used used multiple during retries
// For ARMv8.1 atomic cas the lifetime of the addr and data must be extended to prevent
// them being reused as the target register which must be destroyed early
RefPosition* locationUse = BuildUse(tree->gtCmpXchg.gtOpLocation);
setDelayFree(locationUse);
RefPosition* valueUse = BuildUse(tree->gtCmpXchg.gtOpValue);
setDelayFree(valueUse);
if (!cmpXchgNode->gtOpComparand->isContained())
{
RefPosition* comparandUse = BuildUse(tree->gtCmpXchg.gtOpComparand);
// For ARMv8 exclusives the lifetime of the comparand must be extended because
// it may be used used multiple during retries
if (!compiler->compSupports(InstructionSet_Atomics))
{
setDelayFree(comparandUse);
}
}
// Internals may not collide with target
setInternalRegsDelayFree = true;
buildInternalRegisterUses();
BuildDef(tree);
}
break;
case GT_LOCKADD:
case GT_XADD:
case GT_XCHG:
{
assert(dstCount == (tree->TypeGet() == TYP_VOID) ? 0 : 1);
srcCount = tree->gtGetOp2()->isContained() ? 1 : 2;
if (!compiler->compSupports(InstructionSet_Atomics))
{
// GT_XCHG requires a single internal register; the others require two.
buildInternalIntRegisterDefForNode(tree);
if (tree->OperGet() != GT_XCHG)
{
buildInternalIntRegisterDefForNode(tree);
}
}
assert(!tree->gtGetOp1()->isContained());
RefPosition* op1Use = BuildUse(tree->gtGetOp1());
RefPosition* op2Use = nullptr;
if (!tree->gtGetOp2()->isContained())
{
op2Use = BuildUse(tree->gtGetOp2());
}
// For ARMv8 exclusives the lifetime of the addr and data must be extended because
// it may be used used multiple during retries
if (!compiler->compSupports(InstructionSet_Atomics))
{
// Internals may not collide with target
if (dstCount == 1)
{
setDelayFree(op1Use);
if (op2Use != nullptr)
{
setDelayFree(op2Use);
}
setInternalRegsDelayFree = true;
}
buildInternalRegisterUses();
}
if (dstCount == 1)
{
BuildDef(tree);
}
}
break;
#if FEATURE_ARG_SPLIT
case GT_PUTARG_SPLIT:
srcCount = BuildPutArgSplit(tree->AsPutArgSplit());
dstCount = tree->AsPutArgSplit()->gtNumRegs;
break;
#endif // FEATURE _SPLIT_ARG
case GT_PUTARG_STK:
srcCount = BuildPutArgStk(tree->AsPutArgStk());
break;
case GT_PUTARG_REG:
srcCount = BuildPutArgReg(tree->AsUnOp());
break;
case GT_CALL:
srcCount = BuildCall(tree->AsCall());
if (tree->AsCall()->HasMultiRegRetVal())
{
dstCount = tree->AsCall()->GetReturnTypeDesc()->GetReturnRegCount();
}
break;
case GT_ADDR:
{
// For a GT_ADDR, the child node should not be evaluated into a register
GenTree* child = tree->gtGetOp1();
assert(!isCandidateLocalRef(child));
assert(child->isContained());
assert(dstCount == 1);
srcCount = 0;
BuildDef(tree);
}
break;
case GT_BLK:
case GT_DYN_BLK:
// These should all be eliminated prior to Lowering.
assert(!"Non-store block node in Lowering");
srcCount = 0;
break;
case GT_STORE_BLK:
case GT_STORE_OBJ:
case GT_STORE_DYN_BLK:
srcCount = BuildBlockStore(tree->AsBlk());
break;
case GT_INIT_VAL:
// Always a passthrough of its child's value.
assert(!"INIT_VAL should always be contained");
srcCount = 0;
break;
case GT_LCLHEAP:
{
assert(dstCount == 1);
// Need a variable number of temp regs (see genLclHeap() in codegenamd64.cpp):
// Here '-' means don't care.
//
// Size? Init Memory? # temp regs
// 0 - 0
// const and <=6 ptr words - 0
// const and <PageSize No 0
// >6 ptr words Yes 0
// Non-const Yes 0
// Non-const No 2
//
GenTree* size = tree->gtGetOp1();
if (size->IsCnsIntOrI())
{
assert(size->isContained());
srcCount = 0;
size_t sizeVal = size->gtIntCon.gtIconVal;
if (sizeVal != 0)
{
// Compute the amount of memory to properly STACK_ALIGN.
// Note: The Gentree node is not updated here as it is cheap to recompute stack aligned size.
// This should also help in debugging as we can examine the original size specified with
// localloc.
sizeVal = AlignUp(sizeVal, STACK_ALIGN);
size_t stpCount = sizeVal / (REGSIZE_BYTES * 2);
// For small allocations up to 4 'stp' instructions (i.e. 16 to 64 bytes of localloc)
//
if (stpCount <= 4)
{
// Need no internal registers
}
else if (!compiler->info.compInitMem)
{
// No need to initialize allocated stack space.
if (sizeVal < compiler->eeGetPageSize())
{
// Need no internal registers
}
else
{
// We need two registers: regCnt and RegTmp
buildInternalIntRegisterDefForNode(tree);
buildInternalIntRegisterDefForNode(tree);
}
}
}
}
else
{
srcCount = 1;
if (!compiler->info.compInitMem)
{
buildInternalIntRegisterDefForNode(tree);
buildInternalIntRegisterDefForNode(tree);
}
}
if (!size->isContained())
{
BuildUse(size);
}
buildInternalRegisterUses();
BuildDef(tree);
}
break;
case GT_ARR_BOUNDS_CHECK:
#ifdef FEATURE_SIMD
case GT_SIMD_CHK:
#endif // FEATURE_SIMD
{
GenTreeBoundsChk* node = tree->AsBoundsChk();
// Consumes arrLen & index - has no result
assert(dstCount == 0);
GenTree* intCns = nullptr;
GenTree* other = nullptr;
srcCount = BuildOperandUses(tree->AsBoundsChk()->gtIndex);
srcCount += BuildOperandUses(tree->AsBoundsChk()->gtArrLen);
}
break;
case GT_ARR_ELEM:
// These must have been lowered to GT_ARR_INDEX
noway_assert(!"We should never see a GT_ARR_ELEM in lowering");
srcCount = 0;
assert(dstCount == 0);
break;
case GT_ARR_INDEX:
{
srcCount = 2;
assert(dstCount == 1);
buildInternalIntRegisterDefForNode(tree);
setInternalRegsDelayFree = true;
// For GT_ARR_INDEX, the lifetime of the arrObj must be extended because it is actually used multiple
// times while the result is being computed.
RefPosition* arrObjUse = BuildUse(tree->AsArrIndex()->ArrObj());
setDelayFree(arrObjUse);
BuildUse(tree->AsArrIndex()->IndexExpr());
buildInternalRegisterUses();
BuildDef(tree);
}
break;
case GT_ARR_OFFSET:
// This consumes the offset, if any, the arrObj and the effective index,
// and produces the flattened offset for this dimension.
srcCount = 2;
if (!tree->gtArrOffs.gtOffset->isContained())
{
BuildUse(tree->AsArrOffs()->gtOffset);
srcCount++;
}
BuildUse(tree->AsArrOffs()->gtIndex);
BuildUse(tree->AsArrOffs()->gtArrObj);
assert(dstCount == 1);
buildInternalIntRegisterDefForNode(tree);
buildInternalRegisterUses();
BuildDef(tree);
break;
case GT_LEA:
{
GenTreeAddrMode* lea = tree->AsAddrMode();
GenTree* base = lea->Base();
GenTree* index = lea->Index();
int cns = lea->Offset();
// This LEA is instantiating an address, so we set up the srcCount here.
srcCount = 0;
if (base != nullptr)
{
srcCount++;
BuildUse(base);
}
if (index != nullptr)
{
srcCount++;
BuildUse(index);
}
assert(dstCount == 1);
// On ARM64 we may need a single internal register
// (when both conditions are true then we still only need a single internal register)
if ((index != nullptr) && (cns != 0))
{
// ARM64 does not support both Index and offset so we need an internal register
buildInternalIntRegisterDefForNode(tree);
}
else if (!emitter::emitIns_valid_imm_for_add(cns, EA_8BYTE))
{
// This offset can't be contained in the add instruction, so we need an internal register
buildInternalIntRegisterDefForNode(tree);
}
buildInternalRegisterUses();
BuildDef(tree);
}
break;
case GT_STOREIND:
{
assert(dstCount == 0);
if (compiler->codeGen->gcInfo.gcIsWriteBarrierStoreIndNode(tree))
{
srcCount = BuildGCWriteBarrier(tree);
break;
}
srcCount = BuildIndir(tree->AsIndir());
if (!tree->gtGetOp2()->isContained())
{
BuildUse(tree->gtGetOp2());
srcCount++;
}
}
break;
case GT_NULLCHECK:
// Unlike ARM, ARM64 implements NULLCHECK as a load to REG_ZR, so no internal register
// is required, and it is not a localDefUse.
assert(dstCount == 0);
assert(!tree->gtGetOp1()->isContained());
BuildUse(tree->gtGetOp1());
srcCount = 1;
break;
case GT_IND:
assert(dstCount == 1);
srcCount = BuildIndir(tree->AsIndir());
break;
case GT_CATCH_ARG:
srcCount = 0;
assert(dstCount == 1);
BuildDef(tree, RBM_EXCEPTION_OBJECT);
break;
case GT_CLS_VAR:
srcCount = 0;
// GT_CLS_VAR, by the time we reach the backend, must always
// be a pure use.
// It will produce a result of the type of the
// node, and use an internal register for the address.
assert(dstCount == 1);
assert((tree->gtFlags & (GTF_VAR_DEF | GTF_VAR_USEASG)) == 0);
buildInternalIntRegisterDefForNode(tree);
buildInternalRegisterUses();
BuildDef(tree);
break;
case GT_INDEX_ADDR:
assert(dstCount == 1);
srcCount = BuildBinaryUses(tree->AsOp());
buildInternalIntRegisterDefForNode(tree);
buildInternalRegisterUses();
BuildDef(tree);
break;
} // end switch (tree->OperGet())
if (tree->IsUnusedValue() && (dstCount != 0))
{
isLocalDefUse = true;
}
// We need to be sure that we've set srcCount and dstCount appropriately
assert((dstCount < 2) || tree->IsMultiRegCall());
assert(isLocalDefUse == (tree->IsValue() && tree->IsUnusedValue()));
assert(!tree->IsUnusedValue() || (dstCount != 0));
assert(dstCount == tree->GetRegisterDstCount());
INDEBUG(dumpNodeInfo(tree, dstCandidates, srcCount, dstCount));
return srcCount;
}
