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llvm-mirror/lib/CodeGen/SelectionDAG/InstrEmitter.cpp
Jeremy Morse 409363cd51 [DebugInfo][InstrRef][3/4] Produce DBG_INSTR_REFs for all variable locations 
This patch emits DBG_INSTR_REFs for two remaining flavours of variable
locations that weren't supported: copies, and inter-block VRegs. There are
still some locations that must be represented by DBG_VALUE such as
constants, but they're mostly independent of optimisations.

For variable locations that refer to values defined in different blocks,
vregs are allocated before isel begins, but the defining instruction
might not exist until late in isel. To get around this, emit
DBG_INSTR_REFs in a "half done" state, where the first operand refers to a
VReg. Then at the end of isel, patch these back up to refer to
instructions, using the finalizeDebugInstrRefs method.

Copies are something that I complained about the original RFC, and I
really don't want to have to put instruction numbers on copies. They don't
define a value: they move them. To address this isel, salvageCopySSA
interprets:
 * COPYs,
 * SUBREG_TO_REG,
 * Anything that isCopyInstr thinks is a copy.
And follows chains of copies back to the defining instruction that they
read from. This relies on any physical registers that COPYs read being
defined in the same block, or being entry-block arguments. For the former
we can put an instruction number on the defining instruction; for the
latter we can drop a DBG_PHI that reads the incoming value.

Differential Revision: https://reviews.llvm.org/D88896
2021-07-06 18:31:38 +01:00

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//==--- InstrEmitter.cpp - Emit MachineInstrs for the SelectionDAG class ---==//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This implements the Emit routines for the SelectionDAG class, which creates
// MachineInstrs based on the decisions of the SelectionDAG instruction
// selection.
//
//===----------------------------------------------------------------------===//
#include "InstrEmitter.h"
#include "SDNodeDbgValue.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/CodeGen/MachineConstantPool.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/CodeGen/SelectionDAG.h"
#include "llvm/CodeGen/StackMaps.h"
#include "llvm/CodeGen/TargetInstrInfo.h"
#include "llvm/CodeGen/TargetLowering.h"
#include "llvm/CodeGen/TargetSubtargetInfo.h"
#include "llvm/IR/DataLayout.h"
#include "llvm/IR/DebugInfo.h"
#include "llvm/IR/PseudoProbe.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/MathExtras.h"
#include "llvm/Target/TargetMachine.h"
using namespace llvm;
#define DEBUG_TYPE "instr-emitter"
/// MinRCSize - Smallest register class we allow when constraining virtual
/// registers. If satisfying all register class constraints would require
/// using a smaller register class, emit a COPY to a new virtual register
/// instead.
const unsigned MinRCSize = 4;
/// CountResults - The results of target nodes have register or immediate
/// operands first, then an optional chain, and optional glue operands (which do
/// not go into the resulting MachineInstr).
unsigned InstrEmitter::CountResults(SDNode *Node) {
unsigned N = Node->getNumValues();
while (N && Node->getValueType(N - 1) == MVT::Glue)
--N;
if (N && Node->getValueType(N - 1) == MVT::Other)
--N; // Skip over chain result.
return N;
}
/// countOperands - The inputs to target nodes have any actual inputs first,
/// followed by an optional chain operand, then an optional glue operand.
/// Compute the number of actual operands that will go into the resulting
/// MachineInstr.
///
/// Also count physreg RegisterSDNode and RegisterMaskSDNode operands preceding
/// the chain and glue. These operands may be implicit on the machine instr.
static unsigned countOperands(SDNode *Node, unsigned NumExpUses,
unsigned &NumImpUses) {
unsigned N = Node->getNumOperands();
while (N && Node->getOperand(N - 1).getValueType() == MVT::Glue)
--N;
if (N && Node->getOperand(N - 1).getValueType() == MVT::Other)
--N; // Ignore chain if it exists.
// Count RegisterSDNode and RegisterMaskSDNode operands for NumImpUses.
NumImpUses = N - NumExpUses;
for (unsigned I = N; I > NumExpUses; --I) {
if (isa<RegisterMaskSDNode>(Node->getOperand(I - 1)))
continue;
if (RegisterSDNode *RN = dyn_cast<RegisterSDNode>(Node->getOperand(I - 1)))
if (Register::isPhysicalRegister(RN->getReg()))
continue;
NumImpUses = N - I;
break;
}
return N;
}
/// EmitCopyFromReg - Generate machine code for an CopyFromReg node or an
/// implicit physical register output.
void InstrEmitter::
EmitCopyFromReg(SDNode *Node, unsigned ResNo, bool IsClone, bool IsCloned,
Register SrcReg, DenseMap<SDValue, Register> &VRBaseMap) {
Register VRBase;
if (SrcReg.isVirtual()) {
// Just use the input register directly!
SDValue Op(Node, ResNo);
if (IsClone)
VRBaseMap.erase(Op);
bool isNew = VRBaseMap.insert(std::make_pair(Op, SrcReg)).second;
(void)isNew; // Silence compiler warning.
assert(isNew && "Node emitted out of order - early");
return;
}
// If the node is only used by a CopyToReg and the dest reg is a vreg, use
// the CopyToReg'd destination register instead of creating a new vreg.
bool MatchReg = true;
const TargetRegisterClass *UseRC = nullptr;
MVT VT = Node->getSimpleValueType(ResNo);
// Stick to the preferred register classes for legal types.
if (TLI->isTypeLegal(VT))
UseRC = TLI->getRegClassFor(VT, Node->isDivergent());
if (!IsClone && !IsCloned)
for (SDNode *User : Node->uses()) {
bool Match = true;
if (User->getOpcode() == ISD::CopyToReg &&
User->getOperand(2).getNode() == Node &&
User->getOperand(2).getResNo() == ResNo) {
Register DestReg = cast<RegisterSDNode>(User->getOperand(1))->getReg();
if (DestReg.isVirtual()) {
VRBase = DestReg;
Match = false;
} else if (DestReg != SrcReg)
Match = false;
} else {
for (unsigned i = 0, e = User->getNumOperands(); i != e; ++i) {
SDValue Op = User->getOperand(i);
if (Op.getNode() != Node || Op.getResNo() != ResNo)
continue;
MVT VT = Node->getSimpleValueType(Op.getResNo());
if (VT == MVT::Other || VT == MVT::Glue)
continue;
Match = false;
if (User->isMachineOpcode()) {
const MCInstrDesc &II = TII->get(User->getMachineOpcode());
const TargetRegisterClass *RC = nullptr;
if (i+II.getNumDefs() < II.getNumOperands()) {
RC = TRI->getAllocatableClass(
TII->getRegClass(II, i+II.getNumDefs(), TRI, *MF));
}
if (!UseRC)
UseRC = RC;
else if (RC) {
const TargetRegisterClass *ComRC =
TRI->getCommonSubClass(UseRC, RC);
// If multiple uses expect disjoint register classes, we emit
// copies in AddRegisterOperand.
if (ComRC)
UseRC = ComRC;
}
}
}
}
MatchReg &= Match;
if (VRBase)
break;
}
const TargetRegisterClass *SrcRC = nullptr, *DstRC = nullptr;
SrcRC = TRI->getMinimalPhysRegClass(SrcReg, VT);
// Figure out the register class to create for the destreg.
if (VRBase) {
DstRC = MRI->getRegClass(VRBase);
} else if (UseRC) {
assert(TRI->isTypeLegalForClass(*UseRC, VT) &&
"Incompatible phys register def and uses!");
DstRC = UseRC;
} else
DstRC = SrcRC;
// If all uses are reading from the src physical register and copying the
// register is either impossible or very expensive, then don't create a copy.
if (MatchReg && SrcRC->getCopyCost() < 0) {
VRBase = SrcReg;
} else {
// Create the reg, emit the copy.
VRBase = MRI->createVirtualRegister(DstRC);
BuildMI(*MBB, InsertPos, Node->getDebugLoc(), TII->get(TargetOpcode::COPY),
VRBase).addReg(SrcReg);
}
SDValue Op(Node, ResNo);
if (IsClone)
VRBaseMap.erase(Op);
bool isNew = VRBaseMap.insert(std::make_pair(Op, VRBase)).second;
(void)isNew; // Silence compiler warning.
assert(isNew && "Node emitted out of order - early");
}
void InstrEmitter::CreateVirtualRegisters(SDNode *Node,
MachineInstrBuilder &MIB,
const MCInstrDesc &II,
bool IsClone, bool IsCloned,
DenseMap<SDValue, Register> &VRBaseMap) {
assert(Node->getMachineOpcode() != TargetOpcode::IMPLICIT_DEF &&
"IMPLICIT_DEF should have been handled as a special case elsewhere!");
unsigned NumResults = CountResults(Node);
bool HasVRegVariadicDefs = !MF->getTarget().usesPhysRegsForValues() &&
II.isVariadic() && II.variadicOpsAreDefs();
unsigned NumVRegs = HasVRegVariadicDefs ? NumResults : II.getNumDefs();
if (Node->getMachineOpcode() == TargetOpcode::STATEPOINT)
NumVRegs = NumResults;
for (unsigned i = 0; i < NumVRegs; ++i) {
// If the specific node value is only used by a CopyToReg and the dest reg
// is a vreg in the same register class, use the CopyToReg'd destination
// register instead of creating a new vreg.
Register VRBase;
const TargetRegisterClass *RC =
TRI->getAllocatableClass(TII->getRegClass(II, i, TRI, *MF));
// Always let the value type influence the used register class. The
// constraints on the instruction may be too lax to represent the value
// type correctly. For example, a 64-bit float (X86::FR64) can't live in
// the 32-bit float super-class (X86::FR32).
if (i < NumResults && TLI->isTypeLegal(Node->getSimpleValueType(i))) {
const TargetRegisterClass *VTRC = TLI->getRegClassFor(
Node->getSimpleValueType(i),
(Node->isDivergent() || (RC && TRI->isDivergentRegClass(RC))));
if (RC)
VTRC = TRI->getCommonSubClass(RC, VTRC);
if (VTRC)
RC = VTRC;
}
if (II.OpInfo != nullptr && II.OpInfo[i].isOptionalDef()) {
// Optional def must be a physical register.
VRBase = cast<RegisterSDNode>(Node->getOperand(i-NumResults))->getReg();
assert(VRBase.isPhysical());
MIB.addReg(VRBase, RegState::Define);
}
if (!VRBase && !IsClone && !IsCloned)
for (SDNode *User : Node->uses()) {
if (User->getOpcode() == ISD::CopyToReg &&
User->getOperand(2).getNode() == Node &&
User->getOperand(2).getResNo() == i) {
unsigned Reg = cast<RegisterSDNode>(User->getOperand(1))->getReg();
if (Register::isVirtualRegister(Reg)) {
const TargetRegisterClass *RegRC = MRI->getRegClass(Reg);
if (RegRC == RC) {
VRBase = Reg;
MIB.addReg(VRBase, RegState::Define);
break;
}
}
}
}
// Create the result registers for this node and add the result regs to
// the machine instruction.
if (VRBase == 0) {
assert(RC && "Isn't a register operand!");
VRBase = MRI->createVirtualRegister(RC);
MIB.addReg(VRBase, RegState::Define);
}
// If this def corresponds to a result of the SDNode insert the VRBase into
// the lookup map.
if (i < NumResults) {
SDValue Op(Node, i);
if (IsClone)
VRBaseMap.erase(Op);
bool isNew = VRBaseMap.insert(std::make_pair(Op, VRBase)).second;
(void)isNew; // Silence compiler warning.
assert(isNew && "Node emitted out of order - early");
}
}
}
/// getVR - Return the virtual register corresponding to the specified result
/// of the specified node.
Register InstrEmitter::getVR(SDValue Op,
DenseMap<SDValue, Register> &VRBaseMap) {
if (Op.isMachineOpcode() &&
Op.getMachineOpcode() == TargetOpcode::IMPLICIT_DEF) {
// Add an IMPLICIT_DEF instruction before every use.
// IMPLICIT_DEF can produce any type of result so its MCInstrDesc
// does not include operand register class info.
const TargetRegisterClass *RC = TLI->getRegClassFor(
Op.getSimpleValueType(), Op.getNode()->isDivergent());
Register VReg = MRI->createVirtualRegister(RC);
BuildMI(*MBB, InsertPos, Op.getDebugLoc(),
TII->get(TargetOpcode::IMPLICIT_DEF), VReg);
return VReg;
}
DenseMap<SDValue, Register>::iterator I = VRBaseMap.find(Op);
assert(I != VRBaseMap.end() && "Node emitted out of order - late");
return I->second;
}
/// AddRegisterOperand - Add the specified register as an operand to the
/// specified machine instr. Insert register copies if the register is
/// not in the required register class.
void
InstrEmitter::AddRegisterOperand(MachineInstrBuilder &MIB,
SDValue Op,
unsigned IIOpNum,
const MCInstrDesc *II,
DenseMap<SDValue, Register> &VRBaseMap,
bool IsDebug, bool IsClone, bool IsCloned) {
assert(Op.getValueType() != MVT::Other &&
Op.getValueType() != MVT::Glue &&
"Chain and glue operands should occur at end of operand list!");
// Get/emit the operand.
Register VReg = getVR(Op, VRBaseMap);
const MCInstrDesc &MCID = MIB->getDesc();
bool isOptDef = IIOpNum < MCID.getNumOperands() &&
MCID.OpInfo[IIOpNum].isOptionalDef();
// If the instruction requires a register in a different class, create
// a new virtual register and copy the value into it, but first attempt to
// shrink VReg's register class within reason. For example, if VReg == GR32
// and II requires a GR32_NOSP, just constrain VReg to GR32_NOSP.
if (II) {
const TargetRegisterClass *OpRC = nullptr;
if (IIOpNum < II->getNumOperands())
OpRC = TII->getRegClass(*II, IIOpNum, TRI, *MF);
if (OpRC) {
const TargetRegisterClass *ConstrainedRC
= MRI->constrainRegClass(VReg, OpRC, MinRCSize);
if (!ConstrainedRC) {
OpRC = TRI->getAllocatableClass(OpRC);
assert(OpRC && "Constraints cannot be fulfilled for allocation");
Register NewVReg = MRI->createVirtualRegister(OpRC);
BuildMI(*MBB, InsertPos, Op.getNode()->getDebugLoc(),
TII->get(TargetOpcode::COPY), NewVReg).addReg(VReg);
VReg = NewVReg;
} else {
assert(ConstrainedRC->isAllocatable() &&
"Constraining an allocatable VReg produced an unallocatable class?");
}
}
}
// If this value has only one use, that use is a kill. This is a
// conservative approximation. InstrEmitter does trivial coalescing
// with CopyFromReg nodes, so don't emit kill flags for them.
// Avoid kill flags on Schedule cloned nodes, since there will be
// multiple uses.
// Tied operands are never killed, so we need to check that. And that
// means we need to determine the index of the operand.
bool isKill = Op.hasOneUse() &&
Op.getNode()->getOpcode() != ISD::CopyFromReg &&
!IsDebug &&
!(IsClone || IsCloned);
if (isKill) {
unsigned Idx = MIB->getNumOperands();
while (Idx > 0 &&
MIB->getOperand(Idx-1).isReg() &&
MIB->getOperand(Idx-1).isImplicit())
--Idx;
bool isTied = MCID.getOperandConstraint(Idx, MCOI::TIED_TO) != -1;
if (isTied)
isKill = false;
}
MIB.addReg(VReg, getDefRegState(isOptDef) | getKillRegState(isKill) |
getDebugRegState(IsDebug));
}
/// AddOperand - Add the specified operand to the specified machine instr. II
/// specifies the instruction information for the node, and IIOpNum is the
/// operand number (in the II) that we are adding.
void InstrEmitter::AddOperand(MachineInstrBuilder &MIB,
SDValue Op,
unsigned IIOpNum,
const MCInstrDesc *II,
DenseMap<SDValue, Register> &VRBaseMap,
bool IsDebug, bool IsClone, bool IsCloned) {
if (Op.isMachineOpcode()) {
AddRegisterOperand(MIB, Op, IIOpNum, II, VRBaseMap,
IsDebug, IsClone, IsCloned);
} else if (ConstantSDNode *C = dyn_cast<ConstantSDNode>(Op)) {
MIB.addImm(C->getSExtValue());
} else if (ConstantFPSDNode *F = dyn_cast<ConstantFPSDNode>(Op)) {
MIB.addFPImm(F->getConstantFPValue());
} else if (RegisterSDNode *R = dyn_cast<RegisterSDNode>(Op)) {
Register VReg = R->getReg();
MVT OpVT = Op.getSimpleValueType();
const TargetRegisterClass *IIRC =
II ? TRI->getAllocatableClass(TII->getRegClass(*II, IIOpNum, TRI, *MF))
: nullptr;
const TargetRegisterClass *OpRC =
TLI->isTypeLegal(OpVT)
? TLI->getRegClassFor(OpVT,
Op.getNode()->isDivergent() ||
(IIRC && TRI->isDivergentRegClass(IIRC)))
: nullptr;
if (OpRC && IIRC && OpRC != IIRC && Register::isVirtualRegister(VReg)) {
Register NewVReg = MRI->createVirtualRegister(IIRC);
BuildMI(*MBB, InsertPos, Op.getNode()->getDebugLoc(),
TII->get(TargetOpcode::COPY), NewVReg).addReg(VReg);
VReg = NewVReg;
}
// Turn additional physreg operands into implicit uses on non-variadic
// instructions. This is used by call and return instructions passing
// arguments in registers.
bool Imp = II && (IIOpNum >= II->getNumOperands() && !II->isVariadic());
MIB.addReg(VReg, getImplRegState(Imp));
} else if (RegisterMaskSDNode *RM = dyn_cast<RegisterMaskSDNode>(Op)) {
MIB.addRegMask(RM->getRegMask());
} else if (GlobalAddressSDNode *TGA = dyn_cast<GlobalAddressSDNode>(Op)) {
MIB.addGlobalAddress(TGA->getGlobal(), TGA->getOffset(),
TGA->getTargetFlags());
} else if (BasicBlockSDNode *BBNode = dyn_cast<BasicBlockSDNode>(Op)) {
MIB.addMBB(BBNode->getBasicBlock());
} else if (FrameIndexSDNode *FI = dyn_cast<FrameIndexSDNode>(Op)) {
MIB.addFrameIndex(FI->getIndex());
} else if (JumpTableSDNode *JT = dyn_cast<JumpTableSDNode>(Op)) {
MIB.addJumpTableIndex(JT->getIndex(), JT->getTargetFlags());
} else if (ConstantPoolSDNode *CP = dyn_cast<ConstantPoolSDNode>(Op)) {
int Offset = CP->getOffset();
Align Alignment = CP->getAlign();
unsigned Idx;
MachineConstantPool *MCP = MF->getConstantPool();
if (CP->isMachineConstantPoolEntry())
Idx = MCP->getConstantPoolIndex(CP->getMachineCPVal(), Alignment);
else
Idx = MCP->getConstantPoolIndex(CP->getConstVal(), Alignment);
MIB.addConstantPoolIndex(Idx, Offset, CP->getTargetFlags());
} else if (ExternalSymbolSDNode *ES = dyn_cast<ExternalSymbolSDNode>(Op)) {
MIB.addExternalSymbol(ES->getSymbol(), ES->getTargetFlags());
} else if (auto *SymNode = dyn_cast<MCSymbolSDNode>(Op)) {
MIB.addSym(SymNode->getMCSymbol());
} else if (BlockAddressSDNode *BA = dyn_cast<BlockAddressSDNode>(Op)) {
MIB.addBlockAddress(BA->getBlockAddress(),
BA->getOffset(),
BA->getTargetFlags());
} else if (TargetIndexSDNode *TI = dyn_cast<TargetIndexSDNode>(Op)) {
MIB.addTargetIndex(TI->getIndex(), TI->getOffset(), TI->getTargetFlags());
} else {
assert(Op.getValueType() != MVT::Other &&
Op.getValueType() != MVT::Glue &&
"Chain and glue operands should occur at end of operand list!");
AddRegisterOperand(MIB, Op, IIOpNum, II, VRBaseMap,
IsDebug, IsClone, IsCloned);
}
}
Register InstrEmitter::ConstrainForSubReg(Register VReg, unsigned SubIdx,
MVT VT, bool isDivergent, const DebugLoc &DL) {
const TargetRegisterClass *VRC = MRI->getRegClass(VReg);
const TargetRegisterClass *RC = TRI->getSubClassWithSubReg(VRC, SubIdx);
// RC is a sub-class of VRC that supports SubIdx. Try to constrain VReg
// within reason.
if (RC && RC != VRC)
RC = MRI->constrainRegClass(VReg, RC, MinRCSize);
// VReg has been adjusted. It can be used with SubIdx operands now.
if (RC)
return VReg;
// VReg couldn't be reasonably constrained. Emit a COPY to a new virtual
// register instead.
RC = TRI->getSubClassWithSubReg(TLI->getRegClassFor(VT, isDivergent), SubIdx);
assert(RC && "No legal register class for VT supports that SubIdx");
Register NewReg = MRI->createVirtualRegister(RC);
BuildMI(*MBB, InsertPos, DL, TII->get(TargetOpcode::COPY), NewReg)
.addReg(VReg);
return NewReg;
}
/// EmitSubregNode - Generate machine code for subreg nodes.
///
void InstrEmitter::EmitSubregNode(SDNode *Node,
DenseMap<SDValue, Register> &VRBaseMap,
bool IsClone, bool IsCloned) {
Register VRBase;
unsigned Opc = Node->getMachineOpcode();
// If the node is only used by a CopyToReg and the dest reg is a vreg, use
// the CopyToReg'd destination register instead of creating a new vreg.
for (SDNode *User : Node->uses()) {
if (User->getOpcode() == ISD::CopyToReg &&
User->getOperand(2).getNode() == Node) {
Register DestReg = cast<RegisterSDNode>(User->getOperand(1))->getReg();
if (DestReg.isVirtual()) {
VRBase = DestReg;
break;
}
}
}
if (Opc == TargetOpcode::EXTRACT_SUBREG) {
// EXTRACT_SUBREG is lowered as %dst = COPY %src:sub. There are no
// constraints on the %dst register, COPY can target all legal register
// classes.
unsigned SubIdx = cast<ConstantSDNode>(Node->getOperand(1))->getZExtValue();
const TargetRegisterClass *TRC =
TLI->getRegClassFor(Node->getSimpleValueType(0), Node->isDivergent());
Register Reg;
MachineInstr *DefMI;
RegisterSDNode *R = dyn_cast<RegisterSDNode>(Node->getOperand(0));
if (R && Register::isPhysicalRegister(R->getReg())) {
Reg = R->getReg();
DefMI = nullptr;
} else {
Reg = R ? R->getReg() : getVR(Node->getOperand(0), VRBaseMap);
DefMI = MRI->getVRegDef(Reg);
}
Register SrcReg, DstReg;
unsigned DefSubIdx;
if (DefMI &&
TII->isCoalescableExtInstr(*DefMI, SrcReg, DstReg, DefSubIdx) &&
SubIdx == DefSubIdx &&
TRC == MRI->getRegClass(SrcReg)) {
// Optimize these:
// r1025 = s/zext r1024, 4
// r1026 = extract_subreg r1025, 4
// to a copy
// r1026 = copy r1024
VRBase = MRI->createVirtualRegister(TRC);
BuildMI(*MBB, InsertPos, Node->getDebugLoc(),
TII->get(TargetOpcode::COPY), VRBase).addReg(SrcReg);
MRI->clearKillFlags(SrcReg);
} else {
// Reg may not support a SubIdx sub-register, and we may need to
// constrain its register class or issue a COPY to a compatible register
// class.
if (Reg.isVirtual())
Reg = ConstrainForSubReg(Reg, SubIdx,
Node->getOperand(0).getSimpleValueType(),
Node->isDivergent(), Node->getDebugLoc());
// Create the destreg if it is missing.
if (!VRBase)
VRBase = MRI->createVirtualRegister(TRC);
// Create the extract_subreg machine instruction.
MachineInstrBuilder CopyMI =
BuildMI(*MBB, InsertPos, Node->getDebugLoc(),
TII->get(TargetOpcode::COPY), VRBase);
if (Reg.isVirtual())
CopyMI.addReg(Reg, 0, SubIdx);
else
CopyMI.addReg(TRI->getSubReg(Reg, SubIdx));
}
} else if (Opc == TargetOpcode::INSERT_SUBREG ||
Opc == TargetOpcode::SUBREG_TO_REG) {
SDValue N0 = Node->getOperand(0);
SDValue N1 = Node->getOperand(1);
SDValue N2 = Node->getOperand(2);
unsigned SubIdx = cast<ConstantSDNode>(N2)->getZExtValue();
// Figure out the register class to create for the destreg. It should be
// the largest legal register class supporting SubIdx sub-registers.
// RegisterCoalescer will constrain it further if it decides to eliminate
// the INSERT_SUBREG instruction.
//
// %dst = INSERT_SUBREG %src, %sub, SubIdx
//
// is lowered by TwoAddressInstructionPass to:
//
// %dst = COPY %src
// %dst:SubIdx = COPY %sub
//
// There is no constraint on the %src register class.
//
const TargetRegisterClass *SRC =
TLI->getRegClassFor(Node->getSimpleValueType(0), Node->isDivergent());
SRC = TRI->getSubClassWithSubReg(SRC, SubIdx);
assert(SRC && "No register class supports VT and SubIdx for INSERT_SUBREG");
if (VRBase == 0 || !SRC->hasSubClassEq(MRI->getRegClass(VRBase)))
VRBase = MRI->createVirtualRegister(SRC);
// Create the insert_subreg or subreg_to_reg machine instruction.
MachineInstrBuilder MIB =
BuildMI(*MF, Node->getDebugLoc(), TII->get(Opc), VRBase);
// If creating a subreg_to_reg, then the first input operand
// is an implicit value immediate, otherwise it's a register
if (Opc == TargetOpcode::SUBREG_TO_REG) {
const ConstantSDNode *SD = cast<ConstantSDNode>(N0);
MIB.addImm(SD->getZExtValue());
} else
AddOperand(MIB, N0, 0, nullptr, VRBaseMap, /*IsDebug=*/false,
IsClone, IsCloned);
// Add the subregister being inserted
AddOperand(MIB, N1, 0, nullptr, VRBaseMap, /*IsDebug=*/false,
IsClone, IsCloned);
MIB.addImm(SubIdx);
MBB->insert(InsertPos, MIB);
} else
llvm_unreachable("Node is not insert_subreg, extract_subreg, or subreg_to_reg");
SDValue Op(Node, 0);
bool isNew = VRBaseMap.insert(std::make_pair(Op, VRBase)).second;
(void)isNew; // Silence compiler warning.
assert(isNew && "Node emitted out of order - early");
}
/// EmitCopyToRegClassNode - Generate machine code for COPY_TO_REGCLASS nodes.
/// COPY_TO_REGCLASS is just a normal copy, except that the destination
/// register is constrained to be in a particular register class.
///
void
InstrEmitter::EmitCopyToRegClassNode(SDNode *Node,
DenseMap<SDValue, Register> &VRBaseMap) {
unsigned VReg = getVR(Node->getOperand(0), VRBaseMap);
// Create the new VReg in the destination class and emit a copy.
unsigned DstRCIdx = cast<ConstantSDNode>(Node->getOperand(1))->getZExtValue();
const TargetRegisterClass *DstRC =
TRI->getAllocatableClass(TRI->getRegClass(DstRCIdx));
Register NewVReg = MRI->createVirtualRegister(DstRC);
BuildMI(*MBB, InsertPos, Node->getDebugLoc(), TII->get(TargetOpcode::COPY),
NewVReg).addReg(VReg);
SDValue Op(Node, 0);
bool isNew = VRBaseMap.insert(std::make_pair(Op, NewVReg)).second;
(void)isNew; // Silence compiler warning.
assert(isNew && "Node emitted out of order - early");
}
/// EmitRegSequence - Generate machine code for REG_SEQUENCE nodes.
///
void InstrEmitter::EmitRegSequence(SDNode *Node,
DenseMap<SDValue, Register> &VRBaseMap,
bool IsClone, bool IsCloned) {
unsigned DstRCIdx = cast<ConstantSDNode>(Node->getOperand(0))->getZExtValue();
const TargetRegisterClass *RC = TRI->getRegClass(DstRCIdx);
Register NewVReg = MRI->createVirtualRegister(TRI->getAllocatableClass(RC));
const MCInstrDesc &II = TII->get(TargetOpcode::REG_SEQUENCE);
MachineInstrBuilder MIB = BuildMI(*MF, Node->getDebugLoc(), II, NewVReg);
unsigned NumOps = Node->getNumOperands();
// If the input pattern has a chain, then the root of the corresponding
// output pattern will get a chain as well. This can happen to be a
// REG_SEQUENCE (which is not "guarded" by countOperands/CountResults).
if (NumOps && Node->getOperand(NumOps-1).getValueType() == MVT::Other)
--NumOps; // Ignore chain if it exists.
assert((NumOps & 1) == 1 &&
"REG_SEQUENCE must have an odd number of operands!");
for (unsigned i = 1; i != NumOps; ++i) {
SDValue Op = Node->getOperand(i);
if ((i & 1) == 0) {
RegisterSDNode *R = dyn_cast<RegisterSDNode>(Node->getOperand(i-1));
// Skip physical registers as they don't have a vreg to get and we'll
// insert copies for them in TwoAddressInstructionPass anyway.
if (!R || !Register::isPhysicalRegister(R->getReg())) {
unsigned SubIdx = cast<ConstantSDNode>(Op)->getZExtValue();
unsigned SubReg = getVR(Node->getOperand(i-1), VRBaseMap);
const TargetRegisterClass *TRC = MRI->getRegClass(SubReg);
const TargetRegisterClass *SRC =
TRI->getMatchingSuperRegClass(RC, TRC, SubIdx);
if (SRC && SRC != RC) {
MRI->setRegClass(NewVReg, SRC);
RC = SRC;
}
}
}
AddOperand(MIB, Op, i+1, &II, VRBaseMap, /*IsDebug=*/false,
IsClone, IsCloned);
}
MBB->insert(InsertPos, MIB);
SDValue Op(Node, 0);
bool isNew = VRBaseMap.insert(std::make_pair(Op, NewVReg)).second;
(void)isNew; // Silence compiler warning.
assert(isNew && "Node emitted out of order - early");
}
/// EmitDbgValue - Generate machine instruction for a dbg_value node.
///
MachineInstr *
InstrEmitter::EmitDbgValue(SDDbgValue *SD,
DenseMap<SDValue, Register> &VRBaseMap) {
MDNode *Var = SD->getVariable();
MDNode *Expr = SD->getExpression();
DebugLoc DL = SD->getDebugLoc();
assert(cast<DILocalVariable>(Var)->isValidLocationForIntrinsic(DL) &&
"Expected inlined-at fields to agree");
SD->setIsEmitted();
ArrayRef<SDDbgOperand> LocationOps = SD->getLocationOps();
assert(!LocationOps.empty() && "dbg_value with no location operands?");
if (SD->isInvalidated())
return EmitDbgNoLocation(SD);
// Emit variadic dbg_value nodes as DBG_VALUE_LIST.
if (SD->isVariadic()) {
// DBG_VALUE_LIST := "DBG_VALUE_LIST" var, expression, loc (, loc)*
const MCInstrDesc &DbgValDesc = TII->get(TargetOpcode::DBG_VALUE_LIST);
// Build the DBG_VALUE_LIST instruction base.
auto MIB = BuildMI(*MF, DL, DbgValDesc);
MIB.addMetadata(Var);
MIB.addMetadata(Expr);
AddDbgValueLocationOps(MIB, DbgValDesc, LocationOps, VRBaseMap);
return &*MIB;
}
// Attempt to produce a DBG_INSTR_REF if we've been asked to.
// We currently exclude the possibility of instruction references for
// variadic nodes; if at some point we enable them, this should be moved
// above the variadic block.
if (EmitDebugInstrRefs)
if (auto *InstrRef = EmitDbgInstrRef(SD, VRBaseMap))
return InstrRef;
return EmitDbgValueFromSingleOp(SD, VRBaseMap);
}
void InstrEmitter::AddDbgValueLocationOps(
MachineInstrBuilder &MIB, const MCInstrDesc &DbgValDesc,
ArrayRef<SDDbgOperand> LocationOps,
DenseMap<SDValue, Register> &VRBaseMap) {
for (const SDDbgOperand &Op : LocationOps) {
switch (Op.getKind()) {
case SDDbgOperand::FRAMEIX:
MIB.addFrameIndex(Op.getFrameIx());
break;
case SDDbgOperand::VREG:
MIB.addReg(Op.getVReg(), RegState::Debug);
break;
case SDDbgOperand::SDNODE: {
SDValue V = SDValue(Op.getSDNode(), Op.getResNo());
// It's possible we replaced this SDNode with other(s) and therefore
// didn't generate code for it. It's better to catch these cases where
// they happen and transfer the debug info, but trying to guarantee that
// in all cases would be very fragile; this is a safeguard for any
// that were missed.
if (VRBaseMap.count(V) == 0)
MIB.addReg(0U); // undef
else
AddOperand(MIB, V, (*MIB).getNumOperands(), &DbgValDesc, VRBaseMap,
/*IsDebug=*/true, /*IsClone=*/false, /*IsCloned=*/false);
} break;
case SDDbgOperand::CONST: {
const Value *V = Op.getConst();
if (const ConstantInt *CI = dyn_cast<ConstantInt>(V)) {
if (CI->getBitWidth() > 64)
MIB.addCImm(CI);
else
MIB.addImm(CI->getSExtValue());
} else if (const ConstantFP *CF = dyn_cast<ConstantFP>(V)) {
MIB.addFPImm(CF);
} else if (isa<ConstantPointerNull>(V)) {
// Note: This assumes that all nullptr constants are zero-valued.
MIB.addImm(0);
} else {
// Could be an Undef. In any case insert an Undef so we can see what we
// dropped.
MIB.addReg(0U);
}
} break;
}
}
}
MachineInstr *
InstrEmitter::EmitDbgInstrRef(SDDbgValue *SD,
DenseMap<SDValue, Register> &VRBaseMap) {
assert(!SD->isVariadic());
SDDbgOperand DbgOperand = SD->getLocationOps()[0];
MDNode *Var = SD->getVariable();
MDNode *Expr = SD->getExpression();
DebugLoc DL = SD->getDebugLoc();
const MCInstrDesc &RefII = TII->get(TargetOpcode::DBG_INSTR_REF);
// Handle variable locations that don't actually depend on the instructions
// in the program: constants and stack locations.
if (DbgOperand.getKind() == SDDbgOperand::FRAMEIX ||
DbgOperand.getKind() == SDDbgOperand::CONST)
return EmitDbgValueFromSingleOp(SD, VRBaseMap);
// It may not be immediately possible to identify the MachineInstr that
// defines a VReg, it can depend for example on the order blocks are
// emitted in. When this happens, or when further analysis is needed later,
// produce an instruction like this:
//
// DBG_INSTR_REF %0:gr64, 0, !123, !456
//
// i.e., point the instruction at the vreg, and patch it up later in
// MachineFunction::finalizeDebugInstrRefs.
auto EmitHalfDoneInstrRef = [&](unsigned VReg) -> MachineInstr * {
auto MIB = BuildMI(*MF, DL, RefII);
MIB.addReg(VReg);
MIB.addImm(0);
MIB.addMetadata(Var);
MIB.addMetadata(Expr);
return MIB;
};
// Try to find both the defined register and the instruction defining it.
MachineInstr *DefMI = nullptr;
unsigned VReg;
if (DbgOperand.getKind() == SDDbgOperand::VREG) {
VReg = DbgOperand.getVReg();
// No definition means that block hasn't been emitted yet. Leave a vreg
// reference to be fixed later.
if (!MRI->hasOneDef(VReg))
return EmitHalfDoneInstrRef(VReg);
DefMI = &*MRI->def_instr_begin(VReg);
} else {
assert(DbgOperand.getKind() == SDDbgOperand::SDNODE);
// Look up the corresponding VReg for the given SDNode, if any.
SDNode *Node = DbgOperand.getSDNode();
SDValue Op = SDValue(Node, DbgOperand.getResNo());
DenseMap<SDValue, Register>::iterator I = VRBaseMap.find(Op);
// No VReg -> produce a DBG_VALUE $noreg instead.
if (I==VRBaseMap.end())
return EmitDbgNoLocation(SD);
// Try to pick out a defining instruction at this point.
VReg = getVR(Op, VRBaseMap);
// Again, if there's no instruction defining the VReg right now, fix it up
// later.
if (!MRI->hasOneDef(VReg))
return EmitHalfDoneInstrRef(VReg);
DefMI = &*MRI->def_instr_begin(VReg);
}
// Avoid copy like instructions: they don't define values, only move them.
// Leave a virtual-register reference until it can be fixed up later, to find
// the underlying value definition.
if (DefMI->isCopyLike() || TII->isCopyInstr(*DefMI))
return EmitHalfDoneInstrRef(VReg);
auto MIB = BuildMI(*MF, DL, RefII);
// Find the operand number which defines the specified VReg.
unsigned OperandIdx = 0;
for (const auto &MO : DefMI->operands()) {
if (MO.isReg() && MO.isDef() && MO.getReg() == VReg)
break;
++OperandIdx;
}
assert(OperandIdx < DefMI->getNumOperands());
// Make the DBG_INSTR_REF refer to that instruction, and that operand.
unsigned InstrNum = DefMI->getDebugInstrNum();
MIB.addImm(InstrNum);
MIB.addImm(OperandIdx);
MIB.addMetadata(Var);
MIB.addMetadata(Expr);
return &*MIB;
}
MachineInstr *InstrEmitter::EmitDbgNoLocation(SDDbgValue *SD) {
// An invalidated SDNode must generate an undef DBG_VALUE: although the
// original value is no longer computed, earlier DBG_VALUEs live ranges
// must not leak into later code.
MDNode *Var = SD->getVariable();
MDNode *Expr = SD->getExpression();
DebugLoc DL = SD->getDebugLoc();
auto MIB = BuildMI(*MF, DL, TII->get(TargetOpcode::DBG_VALUE));
MIB.addReg(0U);
MIB.addReg(0U, RegState::Debug);
MIB.addMetadata(Var);
MIB.addMetadata(Expr);
return &*MIB;
}
MachineInstr *
InstrEmitter::EmitDbgValueFromSingleOp(SDDbgValue *SD,
DenseMap<SDValue, Register> &VRBaseMap) {
MDNode *Var = SD->getVariable();
MDNode *Expr = SD->getExpression();
DebugLoc DL = SD->getDebugLoc();
const MCInstrDesc &II = TII->get(TargetOpcode::DBG_VALUE);
assert(SD->getLocationOps().size() == 1 &&
"Non variadic dbg_value should have only one location op");
// Emit non-variadic dbg_value nodes as DBG_VALUE.
// DBG_VALUE := "DBG_VALUE" loc, isIndirect, var, expr
auto MIB = BuildMI(*MF, DL, II);
AddDbgValueLocationOps(MIB, II, SD->getLocationOps(), VRBaseMap);
if (SD->isIndirect())
MIB.addImm(0U);
else
MIB.addReg(0U, RegState::Debug);
return MIB.addMetadata(Var).addMetadata(Expr);
}
MachineInstr *
InstrEmitter::EmitDbgLabel(SDDbgLabel *SD) {
MDNode *Label = SD->getLabel();
DebugLoc DL = SD->getDebugLoc();
assert(cast<DILabel>(Label)->isValidLocationForIntrinsic(DL) &&
"Expected inlined-at fields to agree");
const MCInstrDesc &II = TII->get(TargetOpcode::DBG_LABEL);
MachineInstrBuilder MIB = BuildMI(*MF, DL, II);
MIB.addMetadata(Label);
return &*MIB;
}
/// EmitMachineNode - Generate machine code for a target-specific node and
/// needed dependencies.
///
void InstrEmitter::
EmitMachineNode(SDNode *Node, bool IsClone, bool IsCloned,
DenseMap<SDValue, Register> &VRBaseMap) {
unsigned Opc = Node->getMachineOpcode();
// Handle subreg insert/extract specially
if (Opc == TargetOpcode::EXTRACT_SUBREG ||
Opc == TargetOpcode::INSERT_SUBREG ||
Opc == TargetOpcode::SUBREG_TO_REG) {
EmitSubregNode(Node, VRBaseMap, IsClone, IsCloned);
return;
}
// Handle COPY_TO_REGCLASS specially.
if (Opc == TargetOpcode::COPY_TO_REGCLASS) {
EmitCopyToRegClassNode(Node, VRBaseMap);
return;
}
// Handle REG_SEQUENCE specially.
if (Opc == TargetOpcode::REG_SEQUENCE) {
EmitRegSequence(Node, VRBaseMap, IsClone, IsCloned);
return;
}
if (Opc == TargetOpcode::IMPLICIT_DEF)
// We want a unique VR for each IMPLICIT_DEF use.
return;
const MCInstrDesc &II = TII->get(Opc);
unsigned NumResults = CountResults(Node);
unsigned NumDefs = II.getNumDefs();
const MCPhysReg *ScratchRegs = nullptr;
// Handle STACKMAP and PATCHPOINT specially and then use the generic code.
if (Opc == TargetOpcode::STACKMAP || Opc == TargetOpcode::PATCHPOINT) {
// Stackmaps do not have arguments and do not preserve their calling
// convention. However, to simplify runtime support, they clobber the same
// scratch registers as AnyRegCC.
unsigned CC = CallingConv::AnyReg;
if (Opc == TargetOpcode::PATCHPOINT) {
CC = Node->getConstantOperandVal(PatchPointOpers::CCPos);
NumDefs = NumResults;
}
ScratchRegs = TLI->getScratchRegisters((CallingConv::ID) CC);
} else if (Opc == TargetOpcode::STATEPOINT) {
NumDefs = NumResults;
}
unsigned NumImpUses = 0;
unsigned NodeOperands =
countOperands(Node, II.getNumOperands() - NumDefs, NumImpUses);
bool HasVRegVariadicDefs = !MF->getTarget().usesPhysRegsForValues() &&
II.isVariadic() && II.variadicOpsAreDefs();
bool HasPhysRegOuts = NumResults > NumDefs &&
II.getImplicitDefs() != nullptr && !HasVRegVariadicDefs;
#ifndef NDEBUG
unsigned NumMIOperands = NodeOperands + NumResults;
if (II.isVariadic())
assert(NumMIOperands >= II.getNumOperands() &&
"Too few operands for a variadic node!");
else
assert(NumMIOperands >= II.getNumOperands() &&
NumMIOperands <= II.getNumOperands() + II.getNumImplicitDefs() +
NumImpUses &&
"#operands for dag node doesn't match .td file!");
#endif
// Create the new machine instruction.
MachineInstrBuilder MIB = BuildMI(*MF, Node->getDebugLoc(), II);
// Add result register values for things that are defined by this
// instruction.
if (NumResults) {
CreateVirtualRegisters(Node, MIB, II, IsClone, IsCloned, VRBaseMap);
// Transfer any IR flags from the SDNode to the MachineInstr
MachineInstr *MI = MIB.getInstr();
const SDNodeFlags Flags = Node->getFlags();
if (Flags.hasNoSignedZeros())
MI->setFlag(MachineInstr::MIFlag::FmNsz);
if (Flags.hasAllowReciprocal())
MI->setFlag(MachineInstr::MIFlag::FmArcp);
if (Flags.hasNoNaNs())
MI->setFlag(MachineInstr::MIFlag::FmNoNans);
if (Flags.hasNoInfs())
MI->setFlag(MachineInstr::MIFlag::FmNoInfs);
if (Flags.hasAllowContract())
MI->setFlag(MachineInstr::MIFlag::FmContract);
if (Flags.hasApproximateFuncs())
MI->setFlag(MachineInstr::MIFlag::FmAfn);
if (Flags.hasAllowReassociation())
MI->setFlag(MachineInstr::MIFlag::FmReassoc);
if (Flags.hasNoUnsignedWrap())
MI->setFlag(MachineInstr::MIFlag::NoUWrap);
if (Flags.hasNoSignedWrap())
MI->setFlag(MachineInstr::MIFlag::NoSWrap);
if (Flags.hasExact())
MI->setFlag(MachineInstr::MIFlag::IsExact);
if (Flags.hasNoFPExcept())
MI->setFlag(MachineInstr::MIFlag::NoFPExcept);
}
// Emit all of the actual operands of this instruction, adding them to the
// instruction as appropriate.
bool HasOptPRefs = NumDefs > NumResults;
assert((!HasOptPRefs || !HasPhysRegOuts) &&
"Unable to cope with optional defs and phys regs defs!");
unsigned NumSkip = HasOptPRefs ? NumDefs - NumResults : 0;
for (unsigned i = NumSkip; i != NodeOperands; ++i)
AddOperand(MIB, Node->getOperand(i), i-NumSkip+NumDefs, &II,
VRBaseMap, /*IsDebug=*/false, IsClone, IsCloned);
// Add scratch registers as implicit def and early clobber
if (ScratchRegs)
for (unsigned i = 0; ScratchRegs[i]; ++i)
MIB.addReg(ScratchRegs[i], RegState::ImplicitDefine |
RegState::EarlyClobber);
// Set the memory reference descriptions of this instruction now that it is
// part of the function.
MIB.setMemRefs(cast<MachineSDNode>(Node)->memoperands());
// Insert the instruction into position in the block. This needs to
// happen before any custom inserter hook is called so that the
// hook knows where in the block to insert the replacement code.
MBB->insert(InsertPos, MIB);
// The MachineInstr may also define physregs instead of virtregs. These
// physreg values can reach other instructions in different ways:
//
// 1. When there is a use of a Node value beyond the explicitly defined
// virtual registers, we emit a CopyFromReg for one of the implicitly
// defined physregs. This only happens when HasPhysRegOuts is true.
//
// 2. A CopyFromReg reading a physreg may be glued to this instruction.
//
// 3. A glued instruction may implicitly use a physreg.
//
// 4. A glued instruction may use a RegisterSDNode operand.
//
// Collect all the used physreg defs, and make sure that any unused physreg
// defs are marked as dead.
SmallVector<Register, 8> UsedRegs;
// Additional results must be physical register defs.
if (HasPhysRegOuts) {
for (unsigned i = NumDefs; i < NumResults; ++i) {
Register Reg = II.getImplicitDefs()[i - NumDefs];
if (!Node->hasAnyUseOfValue(i))
continue;
// This implicitly defined physreg has a use.
UsedRegs.push_back(Reg);
EmitCopyFromReg(Node, i, IsClone, IsCloned, Reg, VRBaseMap);
}
}
// Scan the glue chain for any used physregs.
if (Node->getValueType(Node->getNumValues()-1) == MVT::Glue) {
for (SDNode *F = Node->getGluedUser(); F; F = F->getGluedUser()) {
if (F->getOpcode() == ISD::CopyFromReg) {
UsedRegs.push_back(cast<RegisterSDNode>(F->getOperand(1))->getReg());
continue;
} else if (F->getOpcode() == ISD::CopyToReg) {
// Skip CopyToReg nodes that are internal to the glue chain.
continue;
}
// Collect declared implicit uses.
const MCInstrDesc &MCID = TII->get(F->getMachineOpcode());
UsedRegs.append(MCID.getImplicitUses(),
MCID.getImplicitUses() + MCID.getNumImplicitUses());
// In addition to declared implicit uses, we must also check for
// direct RegisterSDNode operands.
for (unsigned i = 0, e = F->getNumOperands(); i != e; ++i)
if (RegisterSDNode *R = dyn_cast<RegisterSDNode>(F->getOperand(i))) {
Register Reg = R->getReg();
if (Reg.isPhysical())
UsedRegs.push_back(Reg);
}
}
}
// Finally mark unused registers as dead.
if (!UsedRegs.empty() || II.getImplicitDefs() || II.hasOptionalDef())
MIB->setPhysRegsDeadExcept(UsedRegs, *TRI);
// STATEPOINT is too 'dynamic' to have meaningful machine description.
// We have to manually tie operands.
if (Opc == TargetOpcode::STATEPOINT && NumDefs > 0) {
assert(!HasPhysRegOuts && "STATEPOINT mishandled");
MachineInstr *MI = MIB;
unsigned Def = 0;
int First = StatepointOpers(MI).getFirstGCPtrIdx();
assert(First > 0 && "Statepoint has Defs but no GC ptr list");
unsigned Use = (unsigned)First;
while (Def < NumDefs) {
if (MI->getOperand(Use).isReg())
MI->tieOperands(Def++, Use);
Use = StackMaps::getNextMetaArgIdx(MI, Use);
}
}
// Run post-isel target hook to adjust this instruction if needed.
if (II.hasPostISelHook())
TLI->AdjustInstrPostInstrSelection(*MIB, Node);
}
/// EmitSpecialNode - Generate machine code for a target-independent node and
/// needed dependencies.
void InstrEmitter::
EmitSpecialNode(SDNode *Node, bool IsClone, bool IsCloned,
DenseMap<SDValue, Register> &VRBaseMap) {
switch (Node->getOpcode()) {
default:
#ifndef NDEBUG
Node->dump();
#endif
llvm_unreachable("This target-independent node should have been selected!");
case ISD::EntryToken:
llvm_unreachable("EntryToken should have been excluded from the schedule!");
case ISD::MERGE_VALUES:
case ISD::TokenFactor: // fall thru
break;
case ISD::CopyToReg: {
Register DestReg = cast<RegisterSDNode>(Node->getOperand(1))->getReg();
SDValue SrcVal = Node->getOperand(2);
if (Register::isVirtualRegister(DestReg) && SrcVal.isMachineOpcode() &&
SrcVal.getMachineOpcode() == TargetOpcode::IMPLICIT_DEF) {
// Instead building a COPY to that vreg destination, build an
// IMPLICIT_DEF instruction instead.
BuildMI(*MBB, InsertPos, Node->getDebugLoc(),
TII->get(TargetOpcode::IMPLICIT_DEF), DestReg);
break;
}
Register SrcReg;
if (RegisterSDNode *R = dyn_cast<RegisterSDNode>(SrcVal))
SrcReg = R->getReg();
else
SrcReg = getVR(SrcVal, VRBaseMap);
if (SrcReg == DestReg) // Coalesced away the copy? Ignore.
break;
BuildMI(*MBB, InsertPos, Node->getDebugLoc(), TII->get(TargetOpcode::COPY),
DestReg).addReg(SrcReg);
break;
}
case ISD::CopyFromReg: {
unsigned SrcReg = cast<RegisterSDNode>(Node->getOperand(1))->getReg();
EmitCopyFromReg(Node, 0, IsClone, IsCloned, SrcReg, VRBaseMap);
break;
}
case ISD::EH_LABEL:
case ISD::ANNOTATION_LABEL: {
unsigned Opc = (Node->getOpcode() == ISD::EH_LABEL)
? TargetOpcode::EH_LABEL
: TargetOpcode::ANNOTATION_LABEL;
MCSymbol *S = cast<LabelSDNode>(Node)->getLabel();
BuildMI(*MBB, InsertPos, Node->getDebugLoc(),
TII->get(Opc)).addSym(S);
break;
}
case ISD::LIFETIME_START:
case ISD::LIFETIME_END: {
unsigned TarOp = (Node->getOpcode() == ISD::LIFETIME_START)
? TargetOpcode::LIFETIME_START
: TargetOpcode::LIFETIME_END;
auto *FI = cast<FrameIndexSDNode>(Node->getOperand(1));
BuildMI(*MBB, InsertPos, Node->getDebugLoc(), TII->get(TarOp))
.addFrameIndex(FI->getIndex());
break;
}
case ISD::PSEUDO_PROBE: {
unsigned TarOp = TargetOpcode::PSEUDO_PROBE;
auto Guid = cast<PseudoProbeSDNode>(Node)->getGuid();
auto Index = cast<PseudoProbeSDNode>(Node)->getIndex();
auto Attr = cast<PseudoProbeSDNode>(Node)->getAttributes();
BuildMI(*MBB, InsertPos, Node->getDebugLoc(), TII->get(TarOp))
.addImm(Guid)
.addImm(Index)
.addImm((uint8_t)PseudoProbeType::Block)
.addImm(Attr);
break;
}
case ISD::INLINEASM:
case ISD::INLINEASM_BR: {
unsigned NumOps = Node->getNumOperands();
if (Node->getOperand(NumOps-1).getValueType() == MVT::Glue)
--NumOps; // Ignore the glue operand.
// Create the inline asm machine instruction.
unsigned TgtOpc = Node->getOpcode() == ISD::INLINEASM_BR
? TargetOpcode::INLINEASM_BR
: TargetOpcode::INLINEASM;
MachineInstrBuilder MIB =
BuildMI(*MF, Node->getDebugLoc(), TII->get(TgtOpc));
// Add the asm string as an external symbol operand.
SDValue AsmStrV = Node->getOperand(InlineAsm::Op_AsmString);
const char *AsmStr = cast<ExternalSymbolSDNode>(AsmStrV)->getSymbol();
MIB.addExternalSymbol(AsmStr);
// Add the HasSideEffect, isAlignStack, AsmDialect, MayLoad and MayStore
// bits.
int64_t ExtraInfo =
cast<ConstantSDNode>(Node->getOperand(InlineAsm::Op_ExtraInfo))->
getZExtValue();
MIB.addImm(ExtraInfo);
// Remember to operand index of the group flags.
SmallVector<unsigned, 8> GroupIdx;
// Remember registers that are part of early-clobber defs.
SmallVector<unsigned, 8> ECRegs;
// Add all of the operand registers to the instruction.
for (unsigned i = InlineAsm::Op_FirstOperand; i != NumOps;) {
unsigned Flags =
cast<ConstantSDNode>(Node->getOperand(i))->getZExtValue();
const unsigned NumVals = InlineAsm::getNumOperandRegisters(Flags);
GroupIdx.push_back(MIB->getNumOperands());
MIB.addImm(Flags);
++i; // Skip the ID value.
switch (InlineAsm::getKind(Flags)) {
default: llvm_unreachable("Bad flags!");
case InlineAsm::Kind_RegDef:
for (unsigned j = 0; j != NumVals; ++j, ++i) {
unsigned Reg = cast<RegisterSDNode>(Node->getOperand(i))->getReg();
// FIXME: Add dead flags for physical and virtual registers defined.
// For now, mark physical register defs as implicit to help fast
// regalloc. This makes inline asm look a lot like calls.
MIB.addReg(Reg,
RegState::Define |
getImplRegState(Register::isPhysicalRegister(Reg)));
}
break;
case InlineAsm::Kind_RegDefEarlyClobber:
case InlineAsm::Kind_Clobber:
for (unsigned j = 0; j != NumVals; ++j, ++i) {
unsigned Reg = cast<RegisterSDNode>(Node->getOperand(i))->getReg();
MIB.addReg(Reg,
RegState::Define | RegState::EarlyClobber |
getImplRegState(Register::isPhysicalRegister(Reg)));
ECRegs.push_back(Reg);
}
break;
case InlineAsm::Kind_RegUse: // Use of register.
case InlineAsm::Kind_Imm: // Immediate.
case InlineAsm::Kind_Mem: // Addressing mode.
// The addressing mode has been selected, just add all of the
// operands to the machine instruction.
for (unsigned j = 0; j != NumVals; ++j, ++i)
AddOperand(MIB, Node->getOperand(i), 0, nullptr, VRBaseMap,
/*IsDebug=*/false, IsClone, IsCloned);
// Manually set isTied bits.
if (InlineAsm::getKind(Flags) == InlineAsm::Kind_RegUse) {
unsigned DefGroup = 0;
if (InlineAsm::isUseOperandTiedToDef(Flags, DefGroup)) {
unsigned DefIdx = GroupIdx[DefGroup] + 1;
unsigned UseIdx = GroupIdx.back() + 1;
for (unsigned j = 0; j != NumVals; ++j)
MIB->tieOperands(DefIdx + j, UseIdx + j);
}
}
break;
}
}
// GCC inline assembly allows input operands to also be early-clobber
// output operands (so long as the operand is written only after it's
// used), but this does not match the semantics of our early-clobber flag.
// If an early-clobber operand register is also an input operand register,
// then remove the early-clobber flag.
for (unsigned Reg : ECRegs) {
if (MIB->readsRegister(Reg, TRI)) {
MachineOperand *MO =
MIB->findRegisterDefOperand(Reg, false, false, TRI);
assert(MO && "No def operand for clobbered register?");
MO->setIsEarlyClobber(false);
}
}
// Get the mdnode from the asm if it exists and add it to the instruction.
SDValue MDV = Node->getOperand(InlineAsm::Op_MDNode);
const MDNode *MD = cast<MDNodeSDNode>(MDV)->getMD();
if (MD)
MIB.addMetadata(MD);
MBB->insert(InsertPos, MIB);
break;
}
}
}
/// InstrEmitter - Construct an InstrEmitter and set it to start inserting
/// at the given position in the given block.
InstrEmitter::InstrEmitter(const TargetMachine &TM, MachineBasicBlock *mbb,
MachineBasicBlock::iterator insertpos)
: MF(mbb->getParent()), MRI(&MF->getRegInfo()),
TII(MF->getSubtarget().getInstrInfo()),
TRI(MF->getSubtarget().getRegisterInfo()),
TLI(MF->getSubtarget().getTargetLowering()), MBB(mbb),
InsertPos(insertpos) {
EmitDebugInstrRefs = TM.Options.ValueTrackingVariableLocations;
}
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