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llvm-mirror/lib/Target/Mips/MipsISelLowering.cpp
Duncan Sands bcdbfb63dc Rename getABITypeSize to getTypePaddedSize, as 
suggested by Chris.

llvm-svn: 62099
2009-01-12 20:38:59 +00:00

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//===-- MipsISelLowering.cpp - Mips 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 defines the interfaces that Mips uses to lower LLVM code into a
// selection DAG.
//
//===----------------------------------------------------------------------===//
#define DEBUG_TYPE "mips-lower"
#include "MipsISelLowering.h"
#include "MipsMachineFunction.h"
#include "MipsTargetMachine.h"
#include "MipsSubtarget.h"
#include "llvm/DerivedTypes.h"
#include "llvm/Function.h"
#include "llvm/GlobalVariable.h"
#include "llvm/Intrinsics.h"
#include "llvm/CallingConv.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"
using namespace llvm;
const char *MipsTargetLowering::
getTargetNodeName(unsigned Opcode) const
{
switch (Opcode)
{
case MipsISD::JmpLink : return "MipsISD::JmpLink";
case MipsISD::Hi : return "MipsISD::Hi";
case MipsISD::Lo : return "MipsISD::Lo";
case MipsISD::GPRel : return "MipsISD::GPRel";
case MipsISD::Ret : return "MipsISD::Ret";
case MipsISD::CMov : return "MipsISD::CMov";
case MipsISD::SelectCC : return "MipsISD::SelectCC";
case MipsISD::FPSelectCC : return "MipsISD::FPSelectCC";
case MipsISD::FPBrcond : return "MipsISD::FPBrcond";
case MipsISD::FPCmp : return "MipsISD::FPCmp";
default : return NULL;
}
}
MipsTargetLowering::
MipsTargetLowering(MipsTargetMachine &TM): TargetLowering(TM)
{
Subtarget = &TM.getSubtarget<MipsSubtarget>();
// Mips does not have i1 type, so use i32 for
// setcc operations results (slt, sgt, ...).
setBooleanContents(ZeroOrOneBooleanContent);
// JumpTable targets must use GOT when using PIC_
setUsesGlobalOffsetTable(true);
// Set up the register classes
addRegisterClass(MVT::i32, Mips::CPURegsRegisterClass);
// When dealing with single precision only, use libcalls
if (!Subtarget->isSingleFloat()) {
addRegisterClass(MVT::f32, Mips::AFGR32RegisterClass);
if (!Subtarget->isFP64bit())
addRegisterClass(MVT::f64, Mips::AFGR64RegisterClass);
} else
addRegisterClass(MVT::f32, Mips::FGR32RegisterClass);
// Legal fp constants
addLegalFPImmediate(APFloat(+0.0f));
// Load extented operations for i1 types must be promoted
setLoadExtAction(ISD::EXTLOAD, MVT::i1, Promote);
setLoadExtAction(ISD::ZEXTLOAD, MVT::i1, Promote);
setLoadExtAction(ISD::SEXTLOAD, MVT::i1, Promote);
// Used by legalize types to correctly generate the setcc result.
// Without this, every float setcc comes with a AND/OR with the result,
// we don't want this, since the fpcmp result goes to a flag register,
// which is used implicitly by brcond and select operations.
AddPromotedToType(ISD::SETCC, MVT::i1, MVT::i32);
// Mips Custom Operations
setOperationAction(ISD::GlobalAddress, MVT::i32, Custom);
setOperationAction(ISD::GlobalTLSAddress, MVT::i32, Custom);
setOperationAction(ISD::RET, MVT::Other, Custom);
setOperationAction(ISD::JumpTable, MVT::i32, Custom);
setOperationAction(ISD::ConstantPool, MVT::i32, Custom);
setOperationAction(ISD::SELECT, MVT::f32, Custom);
setOperationAction(ISD::SELECT, MVT::i32, Custom);
setOperationAction(ISD::SETCC, MVT::f32, Custom);
setOperationAction(ISD::BRCOND, MVT::Other, Custom);
setOperationAction(ISD::DYNAMIC_STACKALLOC, MVT::i32, Custom);
// We custom lower AND/OR to handle the case where the DAG contain 'ands/ors'
// with operands comming from setcc fp comparions. This is necessary since
// the result from these setcc are in a flag registers (FCR31).
setOperationAction(ISD::AND, MVT::i32, Custom);
setOperationAction(ISD::OR, MVT::i32, Custom);
// Operations not directly supported by Mips.
setOperationAction(ISD::BR_JT, MVT::Other, Expand);
setOperationAction(ISD::BR_CC, MVT::Other, Expand);
setOperationAction(ISD::SELECT_CC, MVT::Other, Expand);
setOperationAction(ISD::UINT_TO_FP, MVT::i32, Expand);
setOperationAction(ISD::FP_TO_UINT, MVT::i32, Expand);
setOperationAction(ISD::SIGN_EXTEND_INREG, MVT::i1, Expand);
setOperationAction(ISD::CTPOP, MVT::i32, Expand);
setOperationAction(ISD::CTTZ, MVT::i32, Expand);
setOperationAction(ISD::ROTL, MVT::i32, Expand);
setOperationAction(ISD::SHL_PARTS, MVT::i32, Expand);
setOperationAction(ISD::SRA_PARTS, MVT::i32, Expand);
setOperationAction(ISD::SRL_PARTS, MVT::i32, Expand);
setOperationAction(ISD::FCOPYSIGN, MVT::f32, Expand);
// We don't have line number support yet.
setOperationAction(ISD::DBG_STOPPOINT, MVT::Other, Expand);
setOperationAction(ISD::DEBUG_LOC, MVT::Other, Expand);
setOperationAction(ISD::DBG_LABEL, MVT::Other, Expand);
setOperationAction(ISD::EH_LABEL, MVT::Other, Expand);
// Use the default for now
setOperationAction(ISD::STACKSAVE, MVT::Other, Expand);
setOperationAction(ISD::STACKRESTORE, MVT::Other, Expand);
setOperationAction(ISD::MEMBARRIER, MVT::Other, Expand);
if (Subtarget->isSingleFloat())
setOperationAction(ISD::SELECT_CC, MVT::f64, Expand);
if (!Subtarget->hasSEInReg()) {
setOperationAction(ISD::SIGN_EXTEND_INREG, MVT::i8, Expand);
setOperationAction(ISD::SIGN_EXTEND_INREG, MVT::i16, Expand);
}
if (!Subtarget->hasBitCount())
setOperationAction(ISD::CTLZ, MVT::i32, Expand);
if (!Subtarget->hasSwap())
setOperationAction(ISD::BSWAP, MVT::i32, Expand);
setStackPointerRegisterToSaveRestore(Mips::SP);
computeRegisterProperties();
}
MVT MipsTargetLowering::getSetCCResultType(MVT VT) const {
return MVT::i32;
}
SDValue MipsTargetLowering::
LowerOperation(SDValue Op, SelectionDAG &DAG)
{
switch (Op.getOpcode())
{
case ISD::AND: return LowerANDOR(Op, DAG);
case ISD::BRCOND: return LowerBRCOND(Op, DAG);
case ISD::CALL: return LowerCALL(Op, DAG);
case ISD::ConstantPool: return LowerConstantPool(Op, DAG);
case ISD::DYNAMIC_STACKALLOC: return LowerDYNAMIC_STACKALLOC(Op, DAG);
case ISD::FORMAL_ARGUMENTS: return LowerFORMAL_ARGUMENTS(Op, DAG);
case ISD::GlobalAddress: return LowerGlobalAddress(Op, DAG);
case ISD::GlobalTLSAddress: return LowerGlobalTLSAddress(Op, DAG);
case ISD::JumpTable: return LowerJumpTable(Op, DAG);
case ISD::OR: return LowerANDOR(Op, DAG);
case ISD::RET: return LowerRET(Op, DAG);
case ISD::SELECT: return LowerSELECT(Op, DAG);
case ISD::SETCC: return LowerSETCC(Op, DAG);
}
return SDValue();
}
//===----------------------------------------------------------------------===//
// Lower helper functions
//===----------------------------------------------------------------------===//
// AddLiveIn - This helper function adds the specified physical register to the
// MachineFunction as a live in value. It also creates a corresponding
// virtual register for it.
static unsigned
AddLiveIn(MachineFunction &MF, unsigned PReg, TargetRegisterClass *RC)
{
assert(RC->contains(PReg) && "Not the correct regclass!");
unsigned VReg = MF.getRegInfo().createVirtualRegister(RC);
MF.getRegInfo().addLiveIn(PReg, VReg);
return VReg;
}
// A address must be loaded from a small section if its size is less than the
// small section size threshold. Data in this section must be addressed using
// gp_rel operator.
bool MipsTargetLowering::IsInSmallSection(unsigned Size) {
return (Size > 0 && (Size <= Subtarget->getSSectionThreshold()));
}
// Discover if this global address can be placed into small data/bss section.
bool MipsTargetLowering::IsGlobalInSmallSection(GlobalValue *GV)
{
const TargetData *TD = getTargetData();
const GlobalVariable *GVA = dyn_cast<GlobalVariable>(GV);
if (!GVA)
return false;
const Type *Ty = GV->getType()->getElementType();
unsigned Size = TD->getTypePaddedSize(Ty);
// if this is a internal constant string, there is a special
// section for it, but not in small data/bss.
if (GVA->hasInitializer() && GV->hasInternalLinkage()) {
Constant *C = GVA->getInitializer();
const ConstantArray *CVA = dyn_cast<ConstantArray>(C);
if (CVA && CVA->isCString())
return false;
}
return IsInSmallSection(Size);
}
// Get fp branch code (not opcode) from condition code.
static Mips::FPBranchCode GetFPBranchCodeFromCond(Mips::CondCode CC) {
if (CC >= Mips::FCOND_F && CC <= Mips::FCOND_NGT)
return Mips::BRANCH_T;
if (CC >= Mips::FCOND_T && CC <= Mips::FCOND_GT)
return Mips::BRANCH_F;
return Mips::BRANCH_INVALID;
}
static unsigned FPBranchCodeToOpc(Mips::FPBranchCode BC) {
switch(BC) {
default:
assert(0 && "Unknown branch code");
case Mips::BRANCH_T : return Mips::BC1T;
case Mips::BRANCH_F : return Mips::BC1F;
case Mips::BRANCH_TL : return Mips::BC1TL;
case Mips::BRANCH_FL : return Mips::BC1FL;
}
}
static Mips::CondCode FPCondCCodeToFCC(ISD::CondCode CC) {
switch (CC) {
default: assert(0 && "Unknown fp condition code!");
case ISD::SETEQ:
case ISD::SETOEQ: return Mips::FCOND_EQ;
case ISD::SETUNE: return Mips::FCOND_OGL;
case ISD::SETLT:
case ISD::SETOLT: return Mips::FCOND_OLT;
case ISD::SETGT:
case ISD::SETOGT: return Mips::FCOND_OGT;
case ISD::SETLE:
case ISD::SETOLE: return Mips::FCOND_OLE;
case ISD::SETGE:
case ISD::SETOGE: return Mips::FCOND_OGE;
case ISD::SETULT: return Mips::FCOND_ULT;
case ISD::SETULE: return Mips::FCOND_ULE;
case ISD::SETUGT: return Mips::FCOND_UGT;
case ISD::SETUGE: return Mips::FCOND_UGE;
case ISD::SETUO: return Mips::FCOND_UN;
case ISD::SETO: return Mips::FCOND_OR;
case ISD::SETNE:
case ISD::SETONE: return Mips::FCOND_NEQ;
case ISD::SETUEQ: return Mips::FCOND_UEQ;
}
}
MachineBasicBlock *
MipsTargetLowering::EmitInstrWithCustomInserter(MachineInstr *MI,
MachineBasicBlock *BB)
{
const TargetInstrInfo *TII = getTargetMachine().getInstrInfo();
bool isFPCmp = false;
switch (MI->getOpcode()) {
default: assert(false && "Unexpected instr type to insert");
case Mips::Select_FCC:
case Mips::Select_FCC_SO32:
case Mips::Select_FCC_AS32:
case Mips::Select_FCC_D32:
isFPCmp = true; // FALL THROUGH
case Mips::Select_CC:
case Mips::Select_CC_SO32:
case Mips::Select_CC_AS32:
case Mips::Select_CC_D32: {
// 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 = ...
// setcc r1, r2, r3
// bNE r1, r0, copy1MBB
// fallthrough --> copy0MBB
MachineBasicBlock *thisMBB = BB;
MachineFunction *F = BB->getParent();
MachineBasicBlock *copy0MBB = F->CreateMachineBasicBlock(LLVM_BB);
MachineBasicBlock *sinkMBB = F->CreateMachineBasicBlock(LLVM_BB);
// Emit the right instruction according to the type of the operands compared
if (isFPCmp) {
// Find the condiction code present in the setcc operation.
Mips::CondCode CC = (Mips::CondCode)MI->getOperand(4).getImm();
// Get the branch opcode from the branch code.
unsigned Opc = FPBranchCodeToOpc(GetFPBranchCodeFromCond(CC));
BuildMI(BB, TII->get(Opc)).addMBB(sinkMBB);
} else
BuildMI(BB, TII->get(Mips::BNE)).addReg(MI->getOperand(1).getReg())
.addReg(Mips::ZERO).addMBB(sinkMBB);
F->insert(It, copy0MBB);
F->insert(It, sinkMBB);
// Update machine-CFG edges by first adding all successors of the current
// block to the new block which will contain the Phi node for the select.
for(MachineBasicBlock::succ_iterator i = BB->succ_begin(),
e = BB->succ_end(); i != e; ++i)
sinkMBB->addSuccessor(*i);
// Next, remove all successors of the current block, and add the true
// and fallthrough blocks as its successors.
while(!BB->succ_empty())
BB->removeSuccessor(BB->succ_begin());
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, TII->get(Mips::PHI), MI->getOperand(0).getReg())
.addReg(MI->getOperand(2).getReg()).addMBB(copy0MBB)
.addReg(MI->getOperand(3).getReg()).addMBB(thisMBB);
F->DeleteMachineInstr(MI); // The pseudo instruction is gone now.
return BB;
}
}
}
//===----------------------------------------------------------------------===//
// Misc Lower Operation implementation
//===----------------------------------------------------------------------===//
SDValue MipsTargetLowering::
LowerDYNAMIC_STACKALLOC(SDValue Op, SelectionDAG &DAG)
{
SDValue Chain = Op.getOperand(0);
SDValue Size = Op.getOperand(1);
// Get a reference from Mips stack pointer
SDValue StackPointer = DAG.getCopyFromReg(Chain, Mips::SP, MVT::i32);
// Subtract the dynamic size from the actual stack size to
// obtain the new stack size.
SDValue Sub = DAG.getNode(ISD::SUB, MVT::i32, StackPointer, Size);
// The Sub result contains the new stack start address, so it
// must be placed in the stack pointer register.
Chain = DAG.getCopyToReg(StackPointer.getValue(1), Mips::SP, Sub);
// This node always has two return values: a new stack pointer
// value and a chain
SDValue Ops[2] = { Sub, Chain };
return DAG.getMergeValues(Ops, 2);
}
SDValue MipsTargetLowering::
LowerANDOR(SDValue Op, SelectionDAG &DAG)
{
SDValue LHS = Op.getOperand(0);
SDValue RHS = Op.getOperand(1);
if (LHS.getOpcode() != MipsISD::FPCmp || RHS.getOpcode() != MipsISD::FPCmp)
return Op;
SDValue True = DAG.getConstant(1, MVT::i32);
SDValue False = DAG.getConstant(0, MVT::i32);
SDValue LSEL = DAG.getNode(MipsISD::FPSelectCC, True.getValueType(),
LHS, True, False, LHS.getOperand(2));
SDValue RSEL = DAG.getNode(MipsISD::FPSelectCC, True.getValueType(),
RHS, True, False, RHS.getOperand(2));
return DAG.getNode(Op.getOpcode(), MVT::i32, LSEL, RSEL);
}
SDValue MipsTargetLowering::
LowerBRCOND(SDValue Op, SelectionDAG &DAG)
{
// The first operand is the chain, the second is the condition, the third is
// the block to branch to if the condition is true.
SDValue Chain = Op.getOperand(0);
SDValue Dest = Op.getOperand(2);
if (Op.getOperand(1).getOpcode() != MipsISD::FPCmp)
return Op;
SDValue CondRes = Op.getOperand(1);
SDValue CCNode = CondRes.getOperand(2);
Mips::CondCode CC =
(Mips::CondCode)cast<ConstantSDNode>(CCNode)->getZExtValue();
SDValue BrCode = DAG.getConstant(GetFPBranchCodeFromCond(CC), MVT::i32);
return DAG.getNode(MipsISD::FPBrcond, Op.getValueType(), Chain, BrCode,
Dest, CondRes);
}
SDValue MipsTargetLowering::
LowerSETCC(SDValue Op, SelectionDAG &DAG)
{
// The operands to this are the left and right operands to compare (ops #0,
// and #1) and the condition code to compare them with (op #2) as a
// CondCodeSDNode.
SDValue LHS = Op.getOperand(0);
SDValue RHS = Op.getOperand(1);
ISD::CondCode CC = cast<CondCodeSDNode>(Op.getOperand(2))->get();
return DAG.getNode(MipsISD::FPCmp, Op.getValueType(), LHS, RHS,
DAG.getConstant(FPCondCCodeToFCC(CC), MVT::i32));
}
SDValue MipsTargetLowering::
LowerSELECT(SDValue Op, SelectionDAG &DAG)
{
SDValue Cond = Op.getOperand(0);
SDValue True = Op.getOperand(1);
SDValue False = Op.getOperand(2);
// if the incomming condition comes from a integer compare, the select
// operation must be SelectCC or a conditional move if the subtarget
// supports it.
if (Cond.getOpcode() != MipsISD::FPCmp) {
if (Subtarget->hasCondMov() && !True.getValueType().isFloatingPoint())
return Op;
return DAG.getNode(MipsISD::SelectCC, True.getValueType(),
Cond, True, False);
}
// if the incomming condition comes from fpcmp, the select
// operation must use FPSelectCC.
SDValue CCNode = Cond.getOperand(2);
return DAG.getNode(MipsISD::FPSelectCC, True.getValueType(),
Cond, True, False, CCNode);
}
SDValue MipsTargetLowering::
LowerGlobalAddress(SDValue Op, SelectionDAG &DAG)
{
GlobalValue *GV = cast<GlobalAddressSDNode>(Op)->getGlobal();
SDValue GA = DAG.getTargetGlobalAddress(GV, MVT::i32);
if (!Subtarget->hasABICall()) {
const MVT *VTs = DAG.getNodeValueTypes(MVT::i32);
SDValue Ops[] = { GA };
// %gp_rel relocation
if (!isa<Function>(GV) && IsGlobalInSmallSection(GV)) {
SDValue GPRelNode = DAG.getNode(MipsISD::GPRel, VTs, 1, Ops, 1);
SDValue GOT = DAG.getNode(ISD::GLOBAL_OFFSET_TABLE, MVT::i32);
return DAG.getNode(ISD::ADD, MVT::i32, GOT, GPRelNode);
}
// %hi/%lo relocation
SDValue HiPart = DAG.getNode(MipsISD::Hi, VTs, 1, Ops, 1);
SDValue Lo = DAG.getNode(MipsISD::Lo, MVT::i32, GA);
return DAG.getNode(ISD::ADD, MVT::i32, HiPart, Lo);
} else { // Abicall relocations, TODO: make this cleaner.
SDValue ResNode = DAG.getLoad(MVT::i32, DAG.getEntryNode(), GA, NULL, 0);
// On functions and global targets not internal linked only
// a load from got/GP is necessary for PIC to work.
if (!GV->hasInternalLinkage() || isa<Function>(GV))
return ResNode;
SDValue Lo = DAG.getNode(MipsISD::Lo, MVT::i32, GA);
return DAG.getNode(ISD::ADD, MVT::i32, ResNode, Lo);
}
assert(0 && "Dont know how to handle GlobalAddress");
return SDValue(0,0);
}
SDValue MipsTargetLowering::
LowerGlobalTLSAddress(SDValue Op, SelectionDAG &DAG)
{
assert(0 && "TLS not implemented for MIPS.");
return SDValue(); // Not reached
}
SDValue MipsTargetLowering::
LowerJumpTable(SDValue Op, SelectionDAG &DAG)
{
SDValue ResNode;
SDValue HiPart;
MVT PtrVT = Op.getValueType();
JumpTableSDNode *JT = cast<JumpTableSDNode>(Op);
SDValue JTI = DAG.getTargetJumpTable(JT->getIndex(), PtrVT);
if (getTargetMachine().getRelocationModel() != Reloc::PIC_) {
const MVT *VTs = DAG.getNodeValueTypes(MVT::i32);
SDValue Ops[] = { JTI };
HiPart = DAG.getNode(MipsISD::Hi, VTs, 1, Ops, 1);
} else // Emit Load from Global Pointer
HiPart = DAG.getLoad(MVT::i32, DAG.getEntryNode(), JTI, NULL, 0);
SDValue Lo = DAG.getNode(MipsISD::Lo, MVT::i32, JTI);
ResNode = DAG.getNode(ISD::ADD, MVT::i32, HiPart, Lo);
return ResNode;
}
SDValue MipsTargetLowering::
LowerConstantPool(SDValue Op, SelectionDAG &DAG)
{
SDValue ResNode;
ConstantPoolSDNode *N = cast<ConstantPoolSDNode>(Op);
Constant *C = N->getConstVal();
SDValue CP = DAG.getTargetConstantPool(C, MVT::i32, N->getAlignment());
// gp_rel relocation
// FIXME: we should reference the constant pool using small data sections,
// but the asm printer currently doens't support this feature without
// hacking it. This feature should come soon so we can uncomment the
// stuff below.
//if (!Subtarget->hasABICall() &&
// IsInSmallSection(getTargetData()->getTypePaddedSize(C->getType()))) {
// SDValue GPRelNode = DAG.getNode(MipsISD::GPRel, MVT::i32, CP);
// SDValue GOT = DAG.getNode(ISD::GLOBAL_OFFSET_TABLE, MVT::i32);
// ResNode = DAG.getNode(ISD::ADD, MVT::i32, GOT, GPRelNode);
//} else { // %hi/%lo relocation
SDValue HiPart = DAG.getNode(MipsISD::Hi, MVT::i32, CP);
SDValue Lo = DAG.getNode(MipsISD::Lo, MVT::i32, CP);
ResNode = DAG.getNode(ISD::ADD, MVT::i32, HiPart, Lo);
//}
return ResNode;
}
//===----------------------------------------------------------------------===//
// 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 "MipsGenCallingConv.inc"
//===----------------------------------------------------------------------===//
// CALL Calling Convention Implementation
//===----------------------------------------------------------------------===//
/// LowerCCCCallTo - functions arguments are copied from virtual
/// regs to (physical regs)/(stack frame), CALLSEQ_START and
/// CALLSEQ_END are emitted.
/// TODO: isVarArg, isTailCall.
SDValue MipsTargetLowering::
LowerCALL(SDValue Op, SelectionDAG &DAG)
{
MachineFunction &MF = DAG.getMachineFunction();
CallSDNode *TheCall = cast<CallSDNode>(Op.getNode());
SDValue Chain = TheCall->getChain();
SDValue Callee = TheCall->getCallee();
bool isVarArg = TheCall->isVarArg();
unsigned CC = TheCall->getCallingConv();
MachineFrameInfo *MFI = MF.getFrameInfo();
// Analyze operands of the call, assigning locations to each operand.
SmallVector<CCValAssign, 16> ArgLocs;
CCState CCInfo(CC, isVarArg, getTargetMachine(), ArgLocs);
// To meet O32 ABI, Mips must always allocate 16 bytes on
// the stack (even if less than 4 are used as arguments)
if (Subtarget->isABI_O32()) {
int VTsize = MVT(MVT::i32).getSizeInBits()/8;
MFI->CreateFixedObject(VTsize, (VTsize*3));
}
CCInfo.AnalyzeCallOperands(TheCall, CC_Mips);
// Get a count of how many bytes are to be pushed on the stack.
unsigned NumBytes = CCInfo.getNextStackOffset();
Chain = DAG.getCALLSEQ_START(Chain, DAG.getIntPtrConstant(NumBytes, true));
// With EABI is it possible to have 16 args on registers.
SmallVector<std::pair<unsigned, SDValue>, 16> RegsToPass;
SmallVector<SDValue, 8> MemOpChains;
// First/LastArgStackLoc contains the first/last
// "at stack" argument location.
int LastArgStackLoc = 0;
unsigned FirstStackArgLoc = (Subtarget->isABI_EABI() ? 0 : 16);
// 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, VA.getLocVT(), Arg);
break;
case CCValAssign::ZExt:
Arg = DAG.getNode(ISD::ZERO_EXTEND, VA.getLocVT(), Arg);
break;
case CCValAssign::AExt:
Arg = DAG.getNode(ISD::ANY_EXTEND, 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));
continue;
}
// Register cant get to this point...
assert(VA.isMemLoc());
// Create the frame index object for this incoming parameter
// This guarantees that when allocating Local Area the firsts
// 16 bytes which are alwayes reserved won't be overwritten
// if O32 ABI is used. For EABI the first address is zero.
LastArgStackLoc = (FirstStackArgLoc + VA.getLocMemOffset());
int FI = MFI->CreateFixedObject(VA.getValVT().getSizeInBits()/8,
LastArgStackLoc);
SDValue PtrOff = DAG.getFrameIndex(FI,getPointerTy());
// emit ISD::STORE whichs stores the
// parameter value to a stack Location
MemOpChains.push_back(DAG.getStore(Chain, Arg, PtrOff, NULL, 0));
}
// 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, 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, RegsToPass[i].first,
RegsToPass[i].second, InFlag);
InFlag = Chain.getValue(1);
}
// If the callee is a GlobalAddress/ExternalSymbol node (quite common, every
// direct call is) turn it into a TargetGlobalAddress/TargetExternalSymbol
// node so that legalize doesn't hack it.
if (GlobalAddressSDNode *G = dyn_cast<GlobalAddressSDNode>(Callee))
Callee = DAG.getTargetGlobalAddress(G->getGlobal(), getPointerTy());
else if (ExternalSymbolSDNode *S = dyn_cast<ExternalSymbolSDNode>(Callee))
Callee = DAG.getTargetExternalSymbol(S->getSymbol(), getPointerTy());
// MipsJmpLink = #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(MipsISD::JmpLink, NodeTys, &Ops[0], Ops.size());
InFlag = Chain.getValue(1);
// Create the CALLSEQ_END node.
Chain = DAG.getCALLSEQ_END(Chain, DAG.getIntPtrConstant(NumBytes, true),
DAG.getIntPtrConstant(0, true), InFlag);
InFlag = Chain.getValue(1);
// Create a stack location to hold GP when PIC is used. This stack
// location is used on function prologue to save GP and also after all
// emited CALL's to restore GP.
if (getTargetMachine().getRelocationModel() == Reloc::PIC_) {
// Function can have an arbitrary number of calls, so
// hold the LastArgStackLoc with the biggest offset.
int FI;
MipsFunctionInfo *MipsFI = MF.getInfo<MipsFunctionInfo>();
if (LastArgStackLoc >= MipsFI->getGPStackOffset()) {
LastArgStackLoc = (!LastArgStackLoc) ? (16) : (LastArgStackLoc+4);
// Create the frame index only once. SPOffset here can be anything
// (this will be fixed on processFunctionBeforeFrameFinalized)
if (MipsFI->getGPStackOffset() == -1) {
FI = MFI->CreateFixedObject(4, 0);
MipsFI->setGPFI(FI);
}
MipsFI->setGPStackOffset(LastArgStackLoc);
}
// Reload GP value.
FI = MipsFI->getGPFI();
SDValue FIN = DAG.getFrameIndex(FI,getPointerTy());
SDValue GPLoad = DAG.getLoad(MVT::i32, Chain, FIN, NULL, 0);
Chain = GPLoad.getValue(1);
Chain = DAG.getCopyToReg(Chain, DAG.getRegister(Mips::GP, MVT::i32),
GPLoad, SDValue(0,0));
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 *MipsTargetLowering::
LowerCallResult(SDValue Chain, SDValue InFlag, CallSDNode *TheCall,
unsigned CallingConv, SelectionDAG &DAG) {
bool isVarArg = TheCall->isVarArg();
// Assign locations to each value returned by this call.
SmallVector<CCValAssign, 16> RVLocs;
CCState CCInfo(CallingConv, isVarArg, getTargetMachine(), RVLocs);
CCInfo.AnalyzeCallResult(TheCall, RetCC_Mips);
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, 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, TheCall->getVTList(),
&ResultVals[0], ResultVals.size()).getNode();
}
//===----------------------------------------------------------------------===//
// FORMAL_ARGUMENTS Calling Convention Implementation
//===----------------------------------------------------------------------===//
/// LowerFORMAL_ARGUMENTS - transform physical registers into
/// virtual registers and generate load operations for
/// arguments places on the stack.
/// TODO: isVarArg
SDValue MipsTargetLowering::
LowerFORMAL_ARGUMENTS(SDValue Op, SelectionDAG &DAG)
{
SDValue Root = Op.getOperand(0);
MachineFunction &MF = DAG.getMachineFunction();
MachineFrameInfo *MFI = MF.getFrameInfo();
MipsFunctionInfo *MipsFI = MF.getInfo<MipsFunctionInfo>();
bool isVarArg = cast<ConstantSDNode>(Op.getOperand(2))->getZExtValue() != 0;
unsigned CC = DAG.getMachineFunction().getFunction()->getCallingConv();
unsigned StackReg = MF.getTarget().getRegisterInfo()->getFrameRegister(MF);
// GP must be live into PIC and non-PIC call target.
AddLiveIn(MF, Mips::GP, Mips::CPURegsRegisterClass);
// Assign locations to all of the incoming arguments.
SmallVector<CCValAssign, 16> ArgLocs;
CCState CCInfo(CC, isVarArg, getTargetMachine(), ArgLocs);
CCInfo.AnalyzeFormalArguments(Op.getNode(), CC_Mips);
SmallVector<SDValue, 16> ArgValues;
SDValue StackPtr;
unsigned FirstStackArgLoc = (Subtarget->isABI_EABI() ? 0 : 16);
for (unsigned i = 0, e = ArgLocs.size(); i != e; ++i) {
CCValAssign &VA = ArgLocs[i];
// Arguments stored on registers
if (VA.isRegLoc()) {
MVT RegVT = VA.getLocVT();
TargetRegisterClass *RC = 0;
if (RegVT == MVT::i32)
RC = Mips::CPURegsRegisterClass;
else if (RegVT == MVT::f32) {
if (Subtarget->isSingleFloat())
RC = Mips::FGR32RegisterClass;
else
RC = Mips::AFGR32RegisterClass;
} else if (RegVT == MVT::f64) {
if (!Subtarget->isSingleFloat())
RC = Mips::AFGR64RegisterClass;
} else
assert(0 && "RegVT not supported by FORMAL_ARGUMENTS Lowering");
// Transform the arguments stored on
// physical registers into virtual ones
unsigned Reg = AddLiveIn(DAG.getMachineFunction(), VA.getLocReg(), RC);
SDValue ArgValue = DAG.getCopyFromReg(Root, Reg, RegVT);
// If this is an 8 or 16-bit value, it is really passed promoted
// to 32 bits. Insert an assert[sz]ext to capture this, then
// truncate to the right size.
if (VA.getLocInfo() == CCValAssign::SExt)
ArgValue = DAG.getNode(ISD::AssertSext, RegVT, ArgValue,
DAG.getValueType(VA.getValVT()));
else if (VA.getLocInfo() == CCValAssign::ZExt)
ArgValue = DAG.getNode(ISD::AssertZext, RegVT, ArgValue,
DAG.getValueType(VA.getValVT()));
if (VA.getLocInfo() != CCValAssign::Full)
ArgValue = DAG.getNode(ISD::TRUNCATE, VA.getValVT(), ArgValue);
ArgValues.push_back(ArgValue);
// To meet ABI, when VARARGS are passed on registers, the registers
// must have their values written to the caller stack frame.
if ((isVarArg) && (Subtarget->isABI_O32())) {
if (StackPtr.getNode() == 0)
StackPtr = DAG.getRegister(StackReg, getPointerTy());
// The stack pointer offset is relative to the caller stack frame.
// Since the real stack size is unknown here, a negative SPOffset
// is used so there's a way to adjust these offsets when the stack
// size get known (on EliminateFrameIndex). A dummy SPOffset is
// used instead of a direct negative address (which is recorded to
// be used on emitPrologue) to avoid mis-calc of the first stack
// offset on PEI::calculateFrameObjectOffsets.
// Arguments are always 32-bit.
int FI = MFI->CreateFixedObject(4, 0);
MipsFI->recordStoreVarArgsFI(FI, -(4+(i*4)));
SDValue PtrOff = DAG.getFrameIndex(FI, getPointerTy());
// emit ISD::STORE whichs stores the
// parameter value to a stack Location
ArgValues.push_back(DAG.getStore(Root, ArgValue, PtrOff, NULL, 0));
}
} else { // VA.isRegLoc()
// sanity check
assert(VA.isMemLoc());
// The stack pointer offset is relative to the caller stack frame.
// Since the real stack size is unknown here, a negative SPOffset
// is used so there's a way to adjust these offsets when the stack
// size get known (on EliminateFrameIndex). A dummy SPOffset is
// used instead of a direct negative address (which is recorded to
// be used on emitPrologue) to avoid mis-calc of the first stack
// offset on PEI::calculateFrameObjectOffsets.
// Arguments are always 32-bit.
unsigned ArgSize = VA.getLocVT().getSizeInBits()/8;
int FI = MFI->CreateFixedObject(ArgSize, 0);
MipsFI->recordLoadArgsFI(FI, -(ArgSize+
(FirstStackArgLoc + VA.getLocMemOffset())));
// Create load nodes to retrieve arguments from the stack
SDValue FIN = DAG.getFrameIndex(FI, getPointerTy());
ArgValues.push_back(DAG.getLoad(VA.getValVT(), Root, FIN, NULL, 0));
}
}
// The mips ABIs for returning structs by value requires that we copy
// the sret argument into $v0 for the return. Save the argument into
// a virtual register so that we can access it from the return points.
if (DAG.getMachineFunction().getFunction()->hasStructRetAttr()) {
unsigned Reg = MipsFI->getSRetReturnReg();
if (!Reg) {
Reg = MF.getRegInfo().createVirtualRegister(getRegClassFor(MVT::i32));
MipsFI->setSRetReturnReg(Reg);
}
SDValue Copy = DAG.getCopyToReg(DAG.getEntryNode(), Reg, ArgValues[0]);
Root = DAG.getNode(ISD::TokenFactor, MVT::Other, Copy, Root);
}
ArgValues.push_back(Root);
// Return the new list of results.
return DAG.getNode(ISD::MERGE_VALUES, Op.getNode()->getVTList(),
&ArgValues[0], ArgValues.size()).getValue(Op.getResNo());
}
//===----------------------------------------------------------------------===//
// Return Value Calling Convention Implementation
//===----------------------------------------------------------------------===//
SDValue MipsTargetLowering::
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();
// 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_Mips);
// 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, VA.getLocReg(), Op.getOperand(i*2+1), Flag);
// guarantee that all emitted copies are
// stuck together, avoiding something bad
Flag = Chain.getValue(1);
}
// The mips ABIs for returning structs by value requires that we copy
// the sret argument into $v0 for the return. We saved the argument into
// a virtual register in the entry block, so now we copy the value out
// and into $v0.
if (DAG.getMachineFunction().getFunction()->hasStructRetAttr()) {
MachineFunction &MF = DAG.getMachineFunction();
MipsFunctionInfo *MipsFI = MF.getInfo<MipsFunctionInfo>();
unsigned Reg = MipsFI->getSRetReturnReg();
if (!Reg)
assert(0 && "sret virtual register not created in the entry block");
SDValue Val = DAG.getCopyFromReg(Chain, Reg, getPointerTy());
Chain = DAG.getCopyToReg(Chain, Mips::V0, Val, Flag);
Flag = Chain.getValue(1);
}
// Return on Mips is always a "jr $ra"
if (Flag.getNode())
return DAG.getNode(MipsISD::Ret, MVT::Other,
Chain, DAG.getRegister(Mips::RA, MVT::i32), Flag);
else // Return Void
return DAG.getNode(MipsISD::Ret, MVT::Other,
Chain, DAG.getRegister(Mips::RA, MVT::i32));
}
//===----------------------------------------------------------------------===//
// Mips Inline Assembly Support
//===----------------------------------------------------------------------===//
/// getConstraintType - Given a constraint letter, return the type of
/// constraint it is for this target.
MipsTargetLowering::ConstraintType MipsTargetLowering::
getConstraintType(const std::string &Constraint) const
{
// Mips specific constrainy
// GCC config/mips/constraints.md
//
// 'd' : An address register. Equivalent to r
// unless generating MIPS16 code.
// 'y' : Equivalent to r; retained for
// backwards compatibility.
// 'f' : Floating Point registers.
if (Constraint.size() == 1) {
switch (Constraint[0]) {
default : break;
case 'd':
case 'y':
case 'f':
return C_RegisterClass;
break;
}
}
return TargetLowering::getConstraintType(Constraint);
}
/// getRegClassForInlineAsmConstraint - Given a constraint letter (e.g. "r"),
/// return a list of registers that can be used to satisfy the constraint.
/// This should only be used for C_RegisterClass constraints.
std::pair<unsigned, const TargetRegisterClass*> MipsTargetLowering::
getRegForInlineAsmConstraint(const std::string &Constraint, MVT VT) const
{
if (Constraint.size() == 1) {
switch (Constraint[0]) {
case 'r':
return std::make_pair(0U, Mips::CPURegsRegisterClass);
case 'f':
if (VT == MVT::f32) {
if (Subtarget->isSingleFloat())
return std::make_pair(0U, Mips::FGR32RegisterClass);
else
return std::make_pair(0U, Mips::AFGR32RegisterClass);
}
if (VT == MVT::f64)
if ((!Subtarget->isSingleFloat()) && (!Subtarget->isFP64bit()))
return std::make_pair(0U, Mips::AFGR64RegisterClass);
}
}
return TargetLowering::getRegForInlineAsmConstraint(Constraint, VT);
}
/// Given a register class constraint, like 'r', if this corresponds directly
/// to an LLVM register class, return a register of 0 and the register class
/// pointer.
std::vector<unsigned> MipsTargetLowering::
getRegClassForInlineAsmConstraint(const std::string &Constraint,
MVT VT) const
{
if (Constraint.size() != 1)
return std::vector<unsigned>();
switch (Constraint[0]) {
default : break;
case 'r':
// GCC Mips Constraint Letters
case 'd':
case 'y':
return make_vector<unsigned>(Mips::T0, Mips::T1, Mips::T2, Mips::T3,
Mips::T4, Mips::T5, Mips::T6, Mips::T7, Mips::S0, Mips::S1,
Mips::S2, Mips::S3, Mips::S4, Mips::S5, Mips::S6, Mips::S7,
Mips::T8, 0);
case 'f':
if (VT == MVT::f32) {
if (Subtarget->isSingleFloat())
return make_vector<unsigned>(Mips::F2, Mips::F3, Mips::F4, Mips::F5,
Mips::F6, Mips::F7, Mips::F8, Mips::F9, Mips::F10, Mips::F11,
Mips::F20, Mips::F21, Mips::F22, Mips::F23, Mips::F24,
Mips::F25, Mips::F26, Mips::F27, Mips::F28, Mips::F29,
Mips::F30, Mips::F31, 0);
else
return make_vector<unsigned>(Mips::F2, Mips::F4, Mips::F6, Mips::F8,
Mips::F10, Mips::F20, Mips::F22, Mips::F24, Mips::F26,
Mips::F28, Mips::F30, 0);
}
if (VT == MVT::f64)
if ((!Subtarget->isSingleFloat()) && (!Subtarget->isFP64bit()))
return make_vector<unsigned>(Mips::D1, Mips::D2, Mips::D3, Mips::D4,
Mips::D5, Mips::D10, Mips::D11, Mips::D12, Mips::D13,
Mips::D14, Mips::D15, 0);
}
return std::vector<unsigned>();
}
bool
MipsTargetLowering::isOffsetFoldingLegal(const GlobalAddressSDNode *GA) const {
// The Mips target isn't yet aware of offsets.
return false;
}
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