1 //===-- MipsISelLowering.cpp - Mips DAG Lowering Implementation -----------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file defines the interfaces that Mips uses to lower LLVM code into a
13 //===----------------------------------------------------------------------===//
15 #define DEBUG_TYPE "mips-lower"
17 #include "MipsISelLowering.h"
18 #include "MipsMachineFunction.h"
19 #include "MipsTargetMachine.h"
20 #include "MipsSubtarget.h"
21 #include "llvm/DerivedTypes.h"
22 #include "llvm/Function.h"
23 #include "llvm/GlobalVariable.h"
24 #include "llvm/Intrinsics.h"
25 #include "llvm/CallingConv.h"
26 #include "llvm/CodeGen/CallingConvLower.h"
27 #include "llvm/CodeGen/MachineFrameInfo.h"
28 #include "llvm/CodeGen/MachineFunction.h"
29 #include "llvm/CodeGen/MachineInstrBuilder.h"
30 #include "llvm/CodeGen/MachineRegisterInfo.h"
31 #include "llvm/CodeGen/SelectionDAGISel.h"
32 #include "llvm/CodeGen/ValueTypes.h"
33 #include "llvm/Support/Debug.h"
36 const char *MipsTargetLowering::
37 getTargetNodeName(unsigned Opcode) const
41 case MipsISD::JmpLink : return "MipsISD::JmpLink";
42 case MipsISD::Hi : return "MipsISD::Hi";
43 case MipsISD::Lo : return "MipsISD::Lo";
44 case MipsISD::GPRel : return "MipsISD::GPRel";
45 case MipsISD::Ret : return "MipsISD::Ret";
46 case MipsISD::CMov : return "MipsISD::CMov";
47 case MipsISD::SelectCC : return "MipsISD::SelectCC";
48 case MipsISD::FPSelectCC : return "MipsISD::FPSelectCC";
49 case MipsISD::FPBrcond : return "MipsISD::FPBrcond";
50 case MipsISD::FPCmp : return "MipsISD::FPCmp";
51 default : return NULL;
56 MipsTargetLowering(MipsTargetMachine &TM): TargetLowering(TM)
58 Subtarget = &TM.getSubtarget<MipsSubtarget>();
60 // Mips does not have i1 type, so use i32 for
61 // setcc operations results (slt, sgt, ...).
62 setBooleanContents(ZeroOrOneBooleanContent);
64 // JumpTable targets must use GOT when using PIC_
65 setUsesGlobalOffsetTable(true);
67 // Set up the register classes
68 addRegisterClass(MVT::i32, Mips::CPURegsRegisterClass);
70 // When dealing with single precision only, use libcalls
71 if (!Subtarget->isSingleFloat()) {
72 addRegisterClass(MVT::f32, Mips::AFGR32RegisterClass);
73 if (!Subtarget->isFP64bit())
74 addRegisterClass(MVT::f64, Mips::AFGR64RegisterClass);
76 addRegisterClass(MVT::f32, Mips::FGR32RegisterClass);
79 addLegalFPImmediate(APFloat(+0.0f));
81 // Load extented operations for i1 types must be promoted
82 setLoadExtAction(ISD::EXTLOAD, MVT::i1, Promote);
83 setLoadExtAction(ISD::ZEXTLOAD, MVT::i1, Promote);
84 setLoadExtAction(ISD::SEXTLOAD, MVT::i1, Promote);
86 // Used by legalize types to correctly generate the setcc result.
87 // Without this, every float setcc comes with a AND/OR with the result,
88 // we don't want this, since the fpcmp result goes to a flag register,
89 // which is used implicitly by brcond and select operations.
90 AddPromotedToType(ISD::SETCC, MVT::i1, MVT::i32);
92 // Mips Custom Operations
93 setOperationAction(ISD::GlobalAddress, MVT::i32, Custom);
94 setOperationAction(ISD::GlobalTLSAddress, MVT::i32, Custom);
95 setOperationAction(ISD::RET, MVT::Other, Custom);
96 setOperationAction(ISD::JumpTable, MVT::i32, Custom);
97 setOperationAction(ISD::ConstantPool, MVT::i32, Custom);
98 setOperationAction(ISD::SELECT, MVT::f32, Custom);
99 setOperationAction(ISD::SELECT, MVT::i32, Custom);
100 setOperationAction(ISD::SETCC, MVT::f32, Custom);
101 setOperationAction(ISD::BRCOND, MVT::Other, Custom);
102 setOperationAction(ISD::DYNAMIC_STACKALLOC, MVT::i32, Custom);
104 // We custom lower AND/OR to handle the case where the DAG contain 'ands/ors'
105 // with operands comming from setcc fp comparions. This is necessary since
106 // the result from these setcc are in a flag registers (FCR31).
107 setOperationAction(ISD::AND, MVT::i32, Custom);
108 setOperationAction(ISD::OR, MVT::i32, Custom);
110 // Operations not directly supported by Mips.
111 setOperationAction(ISD::BR_JT, MVT::Other, Expand);
112 setOperationAction(ISD::BR_CC, MVT::Other, Expand);
113 setOperationAction(ISD::SELECT_CC, MVT::Other, Expand);
114 setOperationAction(ISD::UINT_TO_FP, MVT::i32, Expand);
115 setOperationAction(ISD::FP_TO_UINT, MVT::i32, Expand);
116 setOperationAction(ISD::SIGN_EXTEND_INREG, MVT::i1, Expand);
117 setOperationAction(ISD::CTPOP, MVT::i32, Expand);
118 setOperationAction(ISD::CTTZ, MVT::i32, Expand);
119 setOperationAction(ISD::ROTL, MVT::i32, Expand);
120 setOperationAction(ISD::SHL_PARTS, MVT::i32, Expand);
121 setOperationAction(ISD::SRA_PARTS, MVT::i32, Expand);
122 setOperationAction(ISD::SRL_PARTS, MVT::i32, Expand);
123 setOperationAction(ISD::FCOPYSIGN, MVT::f32, Expand);
125 // We don't have line number support yet.
126 setOperationAction(ISD::DBG_STOPPOINT, MVT::Other, Expand);
127 setOperationAction(ISD::DEBUG_LOC, MVT::Other, Expand);
128 setOperationAction(ISD::DBG_LABEL, MVT::Other, Expand);
129 setOperationAction(ISD::EH_LABEL, MVT::Other, Expand);
131 // Use the default for now
132 setOperationAction(ISD::STACKSAVE, MVT::Other, Expand);
133 setOperationAction(ISD::STACKRESTORE, MVT::Other, Expand);
134 setOperationAction(ISD::MEMBARRIER, MVT::Other, Expand);
136 if (Subtarget->isSingleFloat())
137 setOperationAction(ISD::SELECT_CC, MVT::f64, Expand);
139 if (!Subtarget->hasSEInReg()) {
140 setOperationAction(ISD::SIGN_EXTEND_INREG, MVT::i8, Expand);
141 setOperationAction(ISD::SIGN_EXTEND_INREG, MVT::i16, Expand);
144 if (!Subtarget->hasBitCount())
145 setOperationAction(ISD::CTLZ, MVT::i32, Expand);
147 if (!Subtarget->hasSwap())
148 setOperationAction(ISD::BSWAP, MVT::i32, Expand);
150 setStackPointerRegisterToSaveRestore(Mips::SP);
151 computeRegisterProperties();
155 MVT MipsTargetLowering::getSetCCResultType(MVT VT) const {
160 SDValue MipsTargetLowering::
161 LowerOperation(SDValue Op, SelectionDAG &DAG)
163 switch (Op.getOpcode())
165 case ISD::AND: return LowerANDOR(Op, DAG);
166 case ISD::BRCOND: return LowerBRCOND(Op, DAG);
167 case ISD::CALL: return LowerCALL(Op, DAG);
168 case ISD::ConstantPool: return LowerConstantPool(Op, DAG);
169 case ISD::DYNAMIC_STACKALLOC: return LowerDYNAMIC_STACKALLOC(Op, DAG);
170 case ISD::FORMAL_ARGUMENTS: return LowerFORMAL_ARGUMENTS(Op, DAG);
171 case ISD::GlobalAddress: return LowerGlobalAddress(Op, DAG);
172 case ISD::GlobalTLSAddress: return LowerGlobalTLSAddress(Op, DAG);
173 case ISD::JumpTable: return LowerJumpTable(Op, DAG);
174 case ISD::OR: return LowerANDOR(Op, DAG);
175 case ISD::RET: return LowerRET(Op, DAG);
176 case ISD::SELECT: return LowerSELECT(Op, DAG);
177 case ISD::SETCC: return LowerSETCC(Op, DAG);
182 //===----------------------------------------------------------------------===//
183 // Lower helper functions
184 //===----------------------------------------------------------------------===//
186 // AddLiveIn - This helper function adds the specified physical register to the
187 // MachineFunction as a live in value. It also creates a corresponding
188 // virtual register for it.
190 AddLiveIn(MachineFunction &MF, unsigned PReg, TargetRegisterClass *RC)
192 assert(RC->contains(PReg) && "Not the correct regclass!");
193 unsigned VReg = MF.getRegInfo().createVirtualRegister(RC);
194 MF.getRegInfo().addLiveIn(PReg, VReg);
198 // A address must be loaded from a small section if its size is less than the
199 // small section size threshold. Data in this section must be addressed using
201 bool MipsTargetLowering::IsInSmallSection(unsigned Size) {
202 return (Size > 0 && (Size <= Subtarget->getSSectionThreshold()));
205 // Discover if this global address can be placed into small data/bss section.
206 bool MipsTargetLowering::IsGlobalInSmallSection(GlobalValue *GV)
208 const TargetData *TD = getTargetData();
209 const GlobalVariable *GVA = dyn_cast<GlobalVariable>(GV);
214 const Type *Ty = GV->getType()->getElementType();
215 unsigned Size = TD->getTypePaddedSize(Ty);
217 // if this is a internal constant string, there is a special
218 // section for it, but not in small data/bss.
219 if (GVA->hasInitializer() && GV->hasLocalLinkage()) {
220 Constant *C = GVA->getInitializer();
221 const ConstantArray *CVA = dyn_cast<ConstantArray>(C);
222 if (CVA && CVA->isCString())
226 return IsInSmallSection(Size);
229 // Get fp branch code (not opcode) from condition code.
230 static Mips::FPBranchCode GetFPBranchCodeFromCond(Mips::CondCode CC) {
231 if (CC >= Mips::FCOND_F && CC <= Mips::FCOND_NGT)
232 return Mips::BRANCH_T;
234 if (CC >= Mips::FCOND_T && CC <= Mips::FCOND_GT)
235 return Mips::BRANCH_F;
237 return Mips::BRANCH_INVALID;
240 static unsigned FPBranchCodeToOpc(Mips::FPBranchCode BC) {
243 assert(0 && "Unknown branch code");
244 case Mips::BRANCH_T : return Mips::BC1T;
245 case Mips::BRANCH_F : return Mips::BC1F;
246 case Mips::BRANCH_TL : return Mips::BC1TL;
247 case Mips::BRANCH_FL : return Mips::BC1FL;
251 static Mips::CondCode FPCondCCodeToFCC(ISD::CondCode CC) {
253 default: assert(0 && "Unknown fp condition code!");
255 case ISD::SETOEQ: return Mips::FCOND_EQ;
256 case ISD::SETUNE: return Mips::FCOND_OGL;
258 case ISD::SETOLT: return Mips::FCOND_OLT;
260 case ISD::SETOGT: return Mips::FCOND_OGT;
262 case ISD::SETOLE: return Mips::FCOND_OLE;
264 case ISD::SETOGE: return Mips::FCOND_OGE;
265 case ISD::SETULT: return Mips::FCOND_ULT;
266 case ISD::SETULE: return Mips::FCOND_ULE;
267 case ISD::SETUGT: return Mips::FCOND_UGT;
268 case ISD::SETUGE: return Mips::FCOND_UGE;
269 case ISD::SETUO: return Mips::FCOND_UN;
270 case ISD::SETO: return Mips::FCOND_OR;
272 case ISD::SETONE: return Mips::FCOND_NEQ;
273 case ISD::SETUEQ: return Mips::FCOND_UEQ;
278 MipsTargetLowering::EmitInstrWithCustomInserter(MachineInstr *MI,
279 MachineBasicBlock *BB)
281 const TargetInstrInfo *TII = getTargetMachine().getInstrInfo();
282 bool isFPCmp = false;
284 switch (MI->getOpcode()) {
285 default: assert(false && "Unexpected instr type to insert");
286 case Mips::Select_FCC:
287 case Mips::Select_FCC_SO32:
288 case Mips::Select_FCC_AS32:
289 case Mips::Select_FCC_D32:
290 isFPCmp = true; // FALL THROUGH
291 case Mips::Select_CC:
292 case Mips::Select_CC_SO32:
293 case Mips::Select_CC_AS32:
294 case Mips::Select_CC_D32: {
295 // To "insert" a SELECT_CC instruction, we actually have to insert the
296 // diamond control-flow pattern. The incoming instruction knows the
297 // destination vreg to set, the condition code register to branch on, the
298 // true/false values to select between, and a branch opcode to use.
299 const BasicBlock *LLVM_BB = BB->getBasicBlock();
300 MachineFunction::iterator It = BB;
307 // bNE r1, r0, copy1MBB
308 // fallthrough --> copy0MBB
309 MachineBasicBlock *thisMBB = BB;
310 MachineFunction *F = BB->getParent();
311 MachineBasicBlock *copy0MBB = F->CreateMachineBasicBlock(LLVM_BB);
312 MachineBasicBlock *sinkMBB = F->CreateMachineBasicBlock(LLVM_BB);
314 // Emit the right instruction according to the type of the operands compared
316 // Find the condiction code present in the setcc operation.
317 Mips::CondCode CC = (Mips::CondCode)MI->getOperand(4).getImm();
318 // Get the branch opcode from the branch code.
319 unsigned Opc = FPBranchCodeToOpc(GetFPBranchCodeFromCond(CC));
320 BuildMI(BB, TII->get(Opc)).addMBB(sinkMBB);
322 BuildMI(BB, TII->get(Mips::BNE)).addReg(MI->getOperand(1).getReg())
323 .addReg(Mips::ZERO).addMBB(sinkMBB);
325 F->insert(It, copy0MBB);
326 F->insert(It, sinkMBB);
327 // Update machine-CFG edges by first adding all successors of the current
328 // block to the new block which will contain the Phi node for the select.
329 for(MachineBasicBlock::succ_iterator i = BB->succ_begin(),
330 e = BB->succ_end(); i != e; ++i)
331 sinkMBB->addSuccessor(*i);
332 // Next, remove all successors of the current block, and add the true
333 // and fallthrough blocks as its successors.
334 while(!BB->succ_empty())
335 BB->removeSuccessor(BB->succ_begin());
336 BB->addSuccessor(copy0MBB);
337 BB->addSuccessor(sinkMBB);
341 // # fallthrough to sinkMBB
344 // Update machine-CFG edges
345 BB->addSuccessor(sinkMBB);
348 // %Result = phi [ %FalseValue, copy0MBB ], [ %TrueValue, thisMBB ]
351 BuildMI(BB, TII->get(Mips::PHI), MI->getOperand(0).getReg())
352 .addReg(MI->getOperand(2).getReg()).addMBB(copy0MBB)
353 .addReg(MI->getOperand(3).getReg()).addMBB(thisMBB);
355 F->DeleteMachineInstr(MI); // The pseudo instruction is gone now.
361 //===----------------------------------------------------------------------===//
362 // Misc Lower Operation implementation
363 //===----------------------------------------------------------------------===//
365 SDValue MipsTargetLowering::
366 LowerDYNAMIC_STACKALLOC(SDValue Op, SelectionDAG &DAG)
368 SDValue Chain = Op.getOperand(0);
369 SDValue Size = Op.getOperand(1);
370 DebugLoc dl = Op.getDebugLoc();
372 // Get a reference from Mips stack pointer
373 SDValue StackPointer = DAG.getCopyFromReg(Chain, dl, Mips::SP, MVT::i32);
375 // Subtract the dynamic size from the actual stack size to
376 // obtain the new stack size.
377 SDValue Sub = DAG.getNode(ISD::SUB, dl, MVT::i32, StackPointer, Size);
379 // The Sub result contains the new stack start address, so it
380 // must be placed in the stack pointer register.
381 Chain = DAG.getCopyToReg(StackPointer.getValue(1), dl, Mips::SP, Sub);
383 // This node always has two return values: a new stack pointer
385 SDValue Ops[2] = { Sub, Chain };
386 return DAG.getMergeValues(Ops, 2, dl);
389 SDValue MipsTargetLowering::
390 LowerANDOR(SDValue Op, SelectionDAG &DAG)
392 SDValue LHS = Op.getOperand(0);
393 SDValue RHS = Op.getOperand(1);
395 if (LHS.getOpcode() != MipsISD::FPCmp || RHS.getOpcode() != MipsISD::FPCmp)
398 SDValue True = DAG.getConstant(1, MVT::i32);
399 SDValue False = DAG.getConstant(0, MVT::i32);
401 SDValue LSEL = DAG.getNode(MipsISD::FPSelectCC, True.getValueType(),
402 LHS, True, False, LHS.getOperand(2));
403 SDValue RSEL = DAG.getNode(MipsISD::FPSelectCC, True.getValueType(),
404 RHS, True, False, RHS.getOperand(2));
406 return DAG.getNode(Op.getOpcode(), MVT::i32, LSEL, RSEL);
409 SDValue MipsTargetLowering::
410 LowerBRCOND(SDValue Op, SelectionDAG &DAG)
412 // The first operand is the chain, the second is the condition, the third is
413 // the block to branch to if the condition is true.
414 SDValue Chain = Op.getOperand(0);
415 SDValue Dest = Op.getOperand(2);
417 if (Op.getOperand(1).getOpcode() != MipsISD::FPCmp)
420 SDValue CondRes = Op.getOperand(1);
421 SDValue CCNode = CondRes.getOperand(2);
423 (Mips::CondCode)cast<ConstantSDNode>(CCNode)->getZExtValue();
424 SDValue BrCode = DAG.getConstant(GetFPBranchCodeFromCond(CC), MVT::i32);
426 return DAG.getNode(MipsISD::FPBrcond, Op.getValueType(), Chain, BrCode,
430 SDValue MipsTargetLowering::
431 LowerSETCC(SDValue Op, SelectionDAG &DAG)
433 // The operands to this are the left and right operands to compare (ops #0,
434 // and #1) and the condition code to compare them with (op #2) as a
436 SDValue LHS = Op.getOperand(0);
437 SDValue RHS = Op.getOperand(1);
439 ISD::CondCode CC = cast<CondCodeSDNode>(Op.getOperand(2))->get();
441 return DAG.getNode(MipsISD::FPCmp, Op.getValueType(), LHS, RHS,
442 DAG.getConstant(FPCondCCodeToFCC(CC), MVT::i32));
445 SDValue MipsTargetLowering::
446 LowerSELECT(SDValue Op, SelectionDAG &DAG)
448 SDValue Cond = Op.getOperand(0);
449 SDValue True = Op.getOperand(1);
450 SDValue False = Op.getOperand(2);
452 // if the incomming condition comes from a integer compare, the select
453 // operation must be SelectCC or a conditional move if the subtarget
455 if (Cond.getOpcode() != MipsISD::FPCmp) {
456 if (Subtarget->hasCondMov() && !True.getValueType().isFloatingPoint())
458 return DAG.getNode(MipsISD::SelectCC, True.getValueType(),
462 // if the incomming condition comes from fpcmp, the select
463 // operation must use FPSelectCC.
464 SDValue CCNode = Cond.getOperand(2);
465 return DAG.getNode(MipsISD::FPSelectCC, True.getValueType(),
466 Cond, True, False, CCNode);
469 SDValue MipsTargetLowering::
470 LowerGlobalAddress(SDValue Op, SelectionDAG &DAG)
472 DebugLoc dl = Op.getDebugLoc();
473 GlobalValue *GV = cast<GlobalAddressSDNode>(Op)->getGlobal();
474 SDValue GA = DAG.getTargetGlobalAddress(GV, MVT::i32);
476 if (!Subtarget->hasABICall()) {
477 const MVT *VTs = DAG.getNodeValueTypes(MVT::i32);
478 SDValue Ops[] = { GA };
479 // %gp_rel relocation
480 if (!isa<Function>(GV) && IsGlobalInSmallSection(GV)) {
481 SDValue GPRelNode = DAG.getNode(MipsISD::GPRel, VTs, 1, Ops, 1);
482 SDValue GOT = DAG.getNode(ISD::GLOBAL_OFFSET_TABLE, MVT::i32);
483 return DAG.getNode(ISD::ADD, dl, MVT::i32, GOT, GPRelNode);
485 // %hi/%lo relocation
486 SDValue HiPart = DAG.getNode(MipsISD::Hi, dl, VTs, 1, Ops, 1);
487 SDValue Lo = DAG.getNode(MipsISD::Lo, dl, MVT::i32, GA);
488 return DAG.getNode(ISD::ADD, dl, MVT::i32, HiPart, Lo);
490 } else { // Abicall relocations, TODO: make this cleaner.
491 SDValue ResNode = DAG.getLoad(MVT::i32, dl,
492 DAG.getEntryNode(), GA, NULL, 0);
493 // On functions and global targets not internal linked only
494 // a load from got/GP is necessary for PIC to work.
495 if (!GV->hasLocalLinkage() || isa<Function>(GV))
497 SDValue Lo = DAG.getNode(MipsISD::Lo, dl, MVT::i32, GA);
498 return DAG.getNode(ISD::ADD, dl, MVT::i32, ResNode, Lo);
501 assert(0 && "Dont know how to handle GlobalAddress");
505 SDValue MipsTargetLowering::
506 LowerGlobalTLSAddress(SDValue Op, SelectionDAG &DAG)
508 assert(0 && "TLS not implemented for MIPS.");
509 return SDValue(); // Not reached
512 SDValue MipsTargetLowering::
513 LowerJumpTable(SDValue Op, SelectionDAG &DAG)
517 DebugLoc dl = Op.getDebugLoc();
519 MVT PtrVT = Op.getValueType();
520 JumpTableSDNode *JT = cast<JumpTableSDNode>(Op);
521 SDValue JTI = DAG.getTargetJumpTable(JT->getIndex(), PtrVT);
523 if (getTargetMachine().getRelocationModel() != Reloc::PIC_) {
524 const MVT *VTs = DAG.getNodeValueTypes(MVT::i32);
525 SDValue Ops[] = { JTI };
526 HiPart = DAG.getNode(MipsISD::Hi, dl, VTs, 1, Ops, 1);
527 } else // Emit Load from Global Pointer
528 HiPart = DAG.getLoad(MVT::i32, dl, DAG.getEntryNode(), JTI, NULL, 0);
530 SDValue Lo = DAG.getNode(MipsISD::Lo, dl, MVT::i32, JTI);
531 ResNode = DAG.getNode(ISD::ADD, dl, MVT::i32, HiPart, Lo);
536 SDValue MipsTargetLowering::
537 LowerConstantPool(SDValue Op, SelectionDAG &DAG)
540 ConstantPoolSDNode *N = cast<ConstantPoolSDNode>(Op);
541 Constant *C = N->getConstVal();
542 SDValue CP = DAG.getTargetConstantPool(C, MVT::i32, N->getAlignment());
545 // FIXME: we should reference the constant pool using small data sections,
546 // but the asm printer currently doens't support this feature without
547 // hacking it. This feature should come soon so we can uncomment the
549 //if (!Subtarget->hasABICall() &&
550 // IsInSmallSection(getTargetData()->getTypePaddedSize(C->getType()))) {
551 // SDValue GPRelNode = DAG.getNode(MipsISD::GPRel, MVT::i32, CP);
552 // SDValue GOT = DAG.getNode(ISD::GLOBAL_OFFSET_TABLE, MVT::i32);
553 // ResNode = DAG.getNode(ISD::ADD, MVT::i32, GOT, GPRelNode);
554 //} else { // %hi/%lo relocation
555 SDValue HiPart = DAG.getNode(MipsISD::Hi, MVT::i32, CP);
556 SDValue Lo = DAG.getNode(MipsISD::Lo, MVT::i32, CP);
557 ResNode = DAG.getNode(ISD::ADD, MVT::i32, HiPart, Lo);
563 //===----------------------------------------------------------------------===//
564 // Calling Convention Implementation
566 // The lower operations present on calling convention works on this order:
567 // LowerCALL (virt regs --> phys regs, virt regs --> stack)
568 // LowerFORMAL_ARGUMENTS (phys --> virt regs, stack --> virt regs)
569 // LowerRET (virt regs --> phys regs)
570 // LowerCALL (phys regs --> virt regs)
572 //===----------------------------------------------------------------------===//
574 #include "MipsGenCallingConv.inc"
576 //===----------------------------------------------------------------------===//
577 // CALL Calling Convention Implementation
578 //===----------------------------------------------------------------------===//
580 /// LowerCALL - functions arguments are copied from virtual regs to
581 /// (physical regs)/(stack frame), CALLSEQ_START and CALLSEQ_END are emitted.
582 /// TODO: isVarArg, isTailCall.
583 SDValue MipsTargetLowering::
584 LowerCALL(SDValue Op, SelectionDAG &DAG)
586 MachineFunction &MF = DAG.getMachineFunction();
588 CallSDNode *TheCall = cast<CallSDNode>(Op.getNode());
589 SDValue Chain = TheCall->getChain();
590 SDValue Callee = TheCall->getCallee();
591 bool isVarArg = TheCall->isVarArg();
592 unsigned CC = TheCall->getCallingConv();
593 DebugLoc dl = TheCall->getDebugLoc();
595 MachineFrameInfo *MFI = MF.getFrameInfo();
597 // Analyze operands of the call, assigning locations to each operand.
598 SmallVector<CCValAssign, 16> ArgLocs;
599 CCState CCInfo(CC, isVarArg, getTargetMachine(), ArgLocs);
601 // To meet O32 ABI, Mips must always allocate 16 bytes on
602 // the stack (even if less than 4 are used as arguments)
603 if (Subtarget->isABI_O32()) {
604 int VTsize = MVT(MVT::i32).getSizeInBits()/8;
605 MFI->CreateFixedObject(VTsize, (VTsize*3));
608 CCInfo.AnalyzeCallOperands(TheCall, CC_Mips);
610 // Get a count of how many bytes are to be pushed on the stack.
611 unsigned NumBytes = CCInfo.getNextStackOffset();
612 Chain = DAG.getCALLSEQ_START(Chain, DAG.getIntPtrConstant(NumBytes, true));
614 // With EABI is it possible to have 16 args on registers.
615 SmallVector<std::pair<unsigned, SDValue>, 16> RegsToPass;
616 SmallVector<SDValue, 8> MemOpChains;
618 // First/LastArgStackLoc contains the first/last
619 // "at stack" argument location.
620 int LastArgStackLoc = 0;
621 unsigned FirstStackArgLoc = (Subtarget->isABI_EABI() ? 0 : 16);
623 // Walk the register/memloc assignments, inserting copies/loads.
624 for (unsigned i = 0, e = ArgLocs.size(); i != e; ++i) {
625 CCValAssign &VA = ArgLocs[i];
627 // Arguments start after the 5 first operands of ISD::CALL
628 SDValue Arg = TheCall->getArg(i);
630 // Promote the value if needed.
631 switch (VA.getLocInfo()) {
632 default: assert(0 && "Unknown loc info!");
633 case CCValAssign::Full: break;
634 case CCValAssign::SExt:
635 Arg = DAG.getNode(ISD::SIGN_EXTEND, dl, VA.getLocVT(), Arg);
637 case CCValAssign::ZExt:
638 Arg = DAG.getNode(ISD::ZERO_EXTEND, dl, VA.getLocVT(), Arg);
640 case CCValAssign::AExt:
641 Arg = DAG.getNode(ISD::ANY_EXTEND, dl, VA.getLocVT(), Arg);
645 // Arguments that can be passed on register must be kept at
648 RegsToPass.push_back(std::make_pair(VA.getLocReg(), Arg));
652 // Register cant get to this point...
653 assert(VA.isMemLoc());
655 // Create the frame index object for this incoming parameter
656 // This guarantees that when allocating Local Area the firsts
657 // 16 bytes which are alwayes reserved won't be overwritten
658 // if O32 ABI is used. For EABI the first address is zero.
659 LastArgStackLoc = (FirstStackArgLoc + VA.getLocMemOffset());
660 int FI = MFI->CreateFixedObject(VA.getValVT().getSizeInBits()/8,
663 SDValue PtrOff = DAG.getFrameIndex(FI,getPointerTy());
665 // emit ISD::STORE whichs stores the
666 // parameter value to a stack Location
667 MemOpChains.push_back(DAG.getStore(Chain, dl, Arg, PtrOff, NULL, 0));
670 // Transform all store nodes into one single node because all store
671 // nodes are independent of each other.
672 if (!MemOpChains.empty())
673 Chain = DAG.getNode(ISD::TokenFactor, dl, MVT::Other,
674 &MemOpChains[0], MemOpChains.size());
676 // Build a sequence of copy-to-reg nodes chained together with token
677 // chain and flag operands which copy the outgoing args into registers.
678 // The InFlag in necessary since all emited instructions must be
681 for (unsigned i = 0, e = RegsToPass.size(); i != e; ++i) {
682 Chain = DAG.getCopyToReg(Chain, dl, RegsToPass[i].first,
683 RegsToPass[i].second, InFlag);
684 InFlag = Chain.getValue(1);
687 // If the callee is a GlobalAddress/ExternalSymbol node (quite common, every
688 // direct call is) turn it into a TargetGlobalAddress/TargetExternalSymbol
689 // node so that legalize doesn't hack it.
690 if (GlobalAddressSDNode *G = dyn_cast<GlobalAddressSDNode>(Callee))
691 Callee = DAG.getTargetGlobalAddress(G->getGlobal(), getPointerTy());
692 else if (ExternalSymbolSDNode *S = dyn_cast<ExternalSymbolSDNode>(Callee))
693 Callee = DAG.getTargetExternalSymbol(S->getSymbol(), getPointerTy());
696 // MipsJmpLink = #chain, #target_address, #opt_in_flags...
697 // = Chain, Callee, Reg#1, Reg#2, ...
699 // Returns a chain & a flag for retval copy to use.
700 SDVTList NodeTys = DAG.getVTList(MVT::Other, MVT::Flag);
701 SmallVector<SDValue, 8> Ops;
702 Ops.push_back(Chain);
703 Ops.push_back(Callee);
705 // Add argument registers to the end of the list so that they are
706 // known live into the call.
707 for (unsigned i = 0, e = RegsToPass.size(); i != e; ++i)
708 Ops.push_back(DAG.getRegister(RegsToPass[i].first,
709 RegsToPass[i].second.getValueType()));
711 if (InFlag.getNode())
712 Ops.push_back(InFlag);
714 Chain = DAG.getNode(MipsISD::JmpLink, dl, NodeTys, &Ops[0], Ops.size());
715 InFlag = Chain.getValue(1);
717 // Create the CALLSEQ_END node.
718 Chain = DAG.getCALLSEQ_END(Chain, DAG.getIntPtrConstant(NumBytes, true),
719 DAG.getIntPtrConstant(0, true), InFlag);
720 InFlag = Chain.getValue(1);
722 // Create a stack location to hold GP when PIC is used. This stack
723 // location is used on function prologue to save GP and also after all
724 // emited CALL's to restore GP.
725 if (getTargetMachine().getRelocationModel() == Reloc::PIC_) {
726 // Function can have an arbitrary number of calls, so
727 // hold the LastArgStackLoc with the biggest offset.
729 MipsFunctionInfo *MipsFI = MF.getInfo<MipsFunctionInfo>();
730 if (LastArgStackLoc >= MipsFI->getGPStackOffset()) {
731 LastArgStackLoc = (!LastArgStackLoc) ? (16) : (LastArgStackLoc+4);
732 // Create the frame index only once. SPOffset here can be anything
733 // (this will be fixed on processFunctionBeforeFrameFinalized)
734 if (MipsFI->getGPStackOffset() == -1) {
735 FI = MFI->CreateFixedObject(4, 0);
738 MipsFI->setGPStackOffset(LastArgStackLoc);
742 FI = MipsFI->getGPFI();
743 SDValue FIN = DAG.getFrameIndex(FI,getPointerTy());
744 SDValue GPLoad = DAG.getLoad(MVT::i32, dl, Chain, FIN, NULL, 0);
745 Chain = GPLoad.getValue(1);
746 Chain = DAG.getCopyToReg(Chain, dl, DAG.getRegister(Mips::GP, MVT::i32),
747 GPLoad, SDValue(0,0));
748 InFlag = Chain.getValue(1);
751 // Handle result values, copying them out of physregs into vregs that we
753 return SDValue(LowerCallResult(Chain, InFlag, TheCall, CC, DAG), Op.getResNo());
756 /// LowerCallResult - Lower the result values of an ISD::CALL into the
757 /// appropriate copies out of appropriate physical registers. This assumes that
758 /// Chain/InFlag are the input chain/flag to use, and that TheCall is the call
759 /// being lowered. Returns a SDNode with the same number of values as the
761 SDNode *MipsTargetLowering::
762 LowerCallResult(SDValue Chain, SDValue InFlag, CallSDNode *TheCall,
763 unsigned CallingConv, SelectionDAG &DAG) {
765 bool isVarArg = TheCall->isVarArg();
766 DebugLoc dl = TheCall->getDebugLoc();
768 // Assign locations to each value returned by this call.
769 SmallVector<CCValAssign, 16> RVLocs;
770 CCState CCInfo(CallingConv, isVarArg, getTargetMachine(), RVLocs);
772 CCInfo.AnalyzeCallResult(TheCall, RetCC_Mips);
773 SmallVector<SDValue, 8> ResultVals;
775 // Copy all of the result registers out of their specified physreg.
776 for (unsigned i = 0; i != RVLocs.size(); ++i) {
777 Chain = DAG.getCopyFromReg(Chain, dl, RVLocs[i].getLocReg(),
778 RVLocs[i].getValVT(), InFlag).getValue(1);
779 InFlag = Chain.getValue(2);
780 ResultVals.push_back(Chain.getValue(0));
783 ResultVals.push_back(Chain);
785 // Merge everything together with a MERGE_VALUES node.
786 return DAG.getNode(ISD::MERGE_VALUES, dl, TheCall->getVTList(),
787 &ResultVals[0], ResultVals.size()).getNode();
790 //===----------------------------------------------------------------------===//
791 // FORMAL_ARGUMENTS Calling Convention Implementation
792 //===----------------------------------------------------------------------===//
794 /// LowerFORMAL_ARGUMENTS - transform physical registers into
795 /// virtual registers and generate load operations for
796 /// arguments places on the stack.
798 SDValue MipsTargetLowering::
799 LowerFORMAL_ARGUMENTS(SDValue Op, SelectionDAG &DAG)
801 SDValue Root = Op.getOperand(0);
802 MachineFunction &MF = DAG.getMachineFunction();
803 MachineFrameInfo *MFI = MF.getFrameInfo();
804 MipsFunctionInfo *MipsFI = MF.getInfo<MipsFunctionInfo>();
805 DebugLoc dl = Op.getDebugLoc();
807 bool isVarArg = cast<ConstantSDNode>(Op.getOperand(2))->getZExtValue() != 0;
808 unsigned CC = DAG.getMachineFunction().getFunction()->getCallingConv();
810 unsigned StackReg = MF.getTarget().getRegisterInfo()->getFrameRegister(MF);
812 // GP must be live into PIC and non-PIC call target.
813 AddLiveIn(MF, Mips::GP, Mips::CPURegsRegisterClass);
815 // Assign locations to all of the incoming arguments.
816 SmallVector<CCValAssign, 16> ArgLocs;
817 CCState CCInfo(CC, isVarArg, getTargetMachine(), ArgLocs);
819 CCInfo.AnalyzeFormalArguments(Op.getNode(), CC_Mips);
820 SmallVector<SDValue, 16> ArgValues;
823 unsigned FirstStackArgLoc = (Subtarget->isABI_EABI() ? 0 : 16);
825 for (unsigned i = 0, e = ArgLocs.size(); i != e; ++i) {
827 CCValAssign &VA = ArgLocs[i];
829 // Arguments stored on registers
831 MVT RegVT = VA.getLocVT();
832 TargetRegisterClass *RC = 0;
834 if (RegVT == MVT::i32)
835 RC = Mips::CPURegsRegisterClass;
836 else if (RegVT == MVT::f32) {
837 if (Subtarget->isSingleFloat())
838 RC = Mips::FGR32RegisterClass;
840 RC = Mips::AFGR32RegisterClass;
841 } else if (RegVT == MVT::f64) {
842 if (!Subtarget->isSingleFloat())
843 RC = Mips::AFGR64RegisterClass;
845 assert(0 && "RegVT not supported by FORMAL_ARGUMENTS Lowering");
847 // Transform the arguments stored on
848 // physical registers into virtual ones
849 unsigned Reg = AddLiveIn(DAG.getMachineFunction(), VA.getLocReg(), RC);
850 SDValue ArgValue = DAG.getCopyFromReg(Root, dl, Reg, RegVT);
852 // If this is an 8 or 16-bit value, it is really passed promoted
853 // to 32 bits. Insert an assert[sz]ext to capture this, then
854 // truncate to the right size.
855 if (VA.getLocInfo() == CCValAssign::SExt)
856 ArgValue = DAG.getNode(ISD::AssertSext, dl, RegVT, ArgValue,
857 DAG.getValueType(VA.getValVT()));
858 else if (VA.getLocInfo() == CCValAssign::ZExt)
859 ArgValue = DAG.getNode(ISD::AssertZext, dl, RegVT, ArgValue,
860 DAG.getValueType(VA.getValVT()));
862 if (VA.getLocInfo() != CCValAssign::Full)
863 ArgValue = DAG.getNode(ISD::TRUNCATE, dl, VA.getValVT(), ArgValue);
865 ArgValues.push_back(ArgValue);
867 // To meet ABI, when VARARGS are passed on registers, the registers
868 // must have their values written to the caller stack frame.
869 if ((isVarArg) && (Subtarget->isABI_O32())) {
870 if (StackPtr.getNode() == 0)
871 StackPtr = DAG.getRegister(StackReg, getPointerTy());
873 // The stack pointer offset is relative to the caller stack frame.
874 // Since the real stack size is unknown here, a negative SPOffset
875 // is used so there's a way to adjust these offsets when the stack
876 // size get known (on EliminateFrameIndex). A dummy SPOffset is
877 // used instead of a direct negative address (which is recorded to
878 // be used on emitPrologue) to avoid mis-calc of the first stack
879 // offset on PEI::calculateFrameObjectOffsets.
880 // Arguments are always 32-bit.
881 int FI = MFI->CreateFixedObject(4, 0);
882 MipsFI->recordStoreVarArgsFI(FI, -(4+(i*4)));
883 SDValue PtrOff = DAG.getFrameIndex(FI, getPointerTy());
885 // emit ISD::STORE whichs stores the
886 // parameter value to a stack Location
887 ArgValues.push_back(DAG.getStore(Root, dl, ArgValue, PtrOff, NULL, 0));
890 } else { // VA.isRegLoc()
893 assert(VA.isMemLoc());
895 // The stack pointer offset is relative to the caller stack frame.
896 // Since the real stack size is unknown here, a negative SPOffset
897 // is used so there's a way to adjust these offsets when the stack
898 // size get known (on EliminateFrameIndex). A dummy SPOffset is
899 // used instead of a direct negative address (which is recorded to
900 // be used on emitPrologue) to avoid mis-calc of the first stack
901 // offset on PEI::calculateFrameObjectOffsets.
902 // Arguments are always 32-bit.
903 unsigned ArgSize = VA.getLocVT().getSizeInBits()/8;
904 int FI = MFI->CreateFixedObject(ArgSize, 0);
905 MipsFI->recordLoadArgsFI(FI, -(ArgSize+
906 (FirstStackArgLoc + VA.getLocMemOffset())));
908 // Create load nodes to retrieve arguments from the stack
909 SDValue FIN = DAG.getFrameIndex(FI, getPointerTy());
910 ArgValues.push_back(DAG.getLoad(VA.getValVT(), dl, Root, FIN, NULL, 0));
914 // The mips ABIs for returning structs by value requires that we copy
915 // the sret argument into $v0 for the return. Save the argument into
916 // a virtual register so that we can access it from the return points.
917 if (DAG.getMachineFunction().getFunction()->hasStructRetAttr()) {
918 unsigned Reg = MipsFI->getSRetReturnReg();
920 Reg = MF.getRegInfo().createVirtualRegister(getRegClassFor(MVT::i32));
921 MipsFI->setSRetReturnReg(Reg);
923 SDValue Copy = DAG.getCopyToReg(DAG.getEntryNode(), dl, Reg, ArgValues[0]);
924 Root = DAG.getNode(ISD::TokenFactor, dl, MVT::Other, Copy, Root);
927 ArgValues.push_back(Root);
929 // Return the new list of results.
930 return DAG.getNode(ISD::MERGE_VALUES, dl, Op.getNode()->getVTList(),
931 &ArgValues[0], ArgValues.size()).getValue(Op.getResNo());
934 //===----------------------------------------------------------------------===//
935 // Return Value Calling Convention Implementation
936 //===----------------------------------------------------------------------===//
938 SDValue MipsTargetLowering::
939 LowerRET(SDValue Op, SelectionDAG &DAG)
941 // CCValAssign - represent the assignment of
942 // the return value to a location
943 SmallVector<CCValAssign, 16> RVLocs;
944 unsigned CC = DAG.getMachineFunction().getFunction()->getCallingConv();
945 bool isVarArg = DAG.getMachineFunction().getFunction()->isVarArg();
946 DebugLoc dl = Op.getDebugLoc();
948 // CCState - Info about the registers and stack slot.
949 CCState CCInfo(CC, isVarArg, getTargetMachine(), RVLocs);
951 // Analize return values of ISD::RET
952 CCInfo.AnalyzeReturn(Op.getNode(), RetCC_Mips);
954 // If this is the first return lowered for this function, add
955 // the regs to the liveout set for the function.
956 if (DAG.getMachineFunction().getRegInfo().liveout_empty()) {
957 for (unsigned i = 0; i != RVLocs.size(); ++i)
958 if (RVLocs[i].isRegLoc())
959 DAG.getMachineFunction().getRegInfo().addLiveOut(RVLocs[i].getLocReg());
962 // The chain is always operand #0
963 SDValue Chain = Op.getOperand(0);
966 // Copy the result values into the output registers.
967 for (unsigned i = 0; i != RVLocs.size(); ++i) {
968 CCValAssign &VA = RVLocs[i];
969 assert(VA.isRegLoc() && "Can only return in registers!");
971 // ISD::RET => ret chain, (regnum1,val1), ...
972 // So i*2+1 index only the regnums
973 Chain = DAG.getCopyToReg(Chain, dl, VA.getLocReg(),
974 Op.getOperand(i*2+1), Flag);
976 // guarantee that all emitted copies are
977 // stuck together, avoiding something bad
978 Flag = Chain.getValue(1);
981 // The mips ABIs for returning structs by value requires that we copy
982 // the sret argument into $v0 for the return. We saved the argument into
983 // a virtual register in the entry block, so now we copy the value out
985 if (DAG.getMachineFunction().getFunction()->hasStructRetAttr()) {
986 MachineFunction &MF = DAG.getMachineFunction();
987 MipsFunctionInfo *MipsFI = MF.getInfo<MipsFunctionInfo>();
988 unsigned Reg = MipsFI->getSRetReturnReg();
991 assert(0 && "sret virtual register not created in the entry block");
992 SDValue Val = DAG.getCopyFromReg(Chain, dl, Reg, getPointerTy());
994 Chain = DAG.getCopyToReg(Chain, dl, Mips::V0, Val, Flag);
995 Flag = Chain.getValue(1);
998 // Return on Mips is always a "jr $ra"
1000 return DAG.getNode(MipsISD::Ret, dl, MVT::Other,
1001 Chain, DAG.getRegister(Mips::RA, MVT::i32), Flag);
1003 return DAG.getNode(MipsISD::Ret, dl, MVT::Other,
1004 Chain, DAG.getRegister(Mips::RA, MVT::i32));
1007 //===----------------------------------------------------------------------===//
1008 // Mips Inline Assembly Support
1009 //===----------------------------------------------------------------------===//
1011 /// getConstraintType - Given a constraint letter, return the type of
1012 /// constraint it is for this target.
1013 MipsTargetLowering::ConstraintType MipsTargetLowering::
1014 getConstraintType(const std::string &Constraint) const
1016 // Mips specific constrainy
1017 // GCC config/mips/constraints.md
1019 // 'd' : An address register. Equivalent to r
1020 // unless generating MIPS16 code.
1021 // 'y' : Equivalent to r; retained for
1022 // backwards compatibility.
1023 // 'f' : Floating Point registers.
1024 if (Constraint.size() == 1) {
1025 switch (Constraint[0]) {
1030 return C_RegisterClass;
1034 return TargetLowering::getConstraintType(Constraint);
1037 /// getRegClassForInlineAsmConstraint - Given a constraint letter (e.g. "r"),
1038 /// return a list of registers that can be used to satisfy the constraint.
1039 /// This should only be used for C_RegisterClass constraints.
1040 std::pair<unsigned, const TargetRegisterClass*> MipsTargetLowering::
1041 getRegForInlineAsmConstraint(const std::string &Constraint, MVT VT) const
1043 if (Constraint.size() == 1) {
1044 switch (Constraint[0]) {
1046 return std::make_pair(0U, Mips::CPURegsRegisterClass);
1048 if (VT == MVT::f32) {
1049 if (Subtarget->isSingleFloat())
1050 return std::make_pair(0U, Mips::FGR32RegisterClass);
1052 return std::make_pair(0U, Mips::AFGR32RegisterClass);
1055 if ((!Subtarget->isSingleFloat()) && (!Subtarget->isFP64bit()))
1056 return std::make_pair(0U, Mips::AFGR64RegisterClass);
1059 return TargetLowering::getRegForInlineAsmConstraint(Constraint, VT);
1062 /// Given a register class constraint, like 'r', if this corresponds directly
1063 /// to an LLVM register class, return a register of 0 and the register class
1065 std::vector<unsigned> MipsTargetLowering::
1066 getRegClassForInlineAsmConstraint(const std::string &Constraint,
1069 if (Constraint.size() != 1)
1070 return std::vector<unsigned>();
1072 switch (Constraint[0]) {
1075 // GCC Mips Constraint Letters
1078 return make_vector<unsigned>(Mips::T0, Mips::T1, Mips::T2, Mips::T3,
1079 Mips::T4, Mips::T5, Mips::T6, Mips::T7, Mips::S0, Mips::S1,
1080 Mips::S2, Mips::S3, Mips::S4, Mips::S5, Mips::S6, Mips::S7,
1084 if (VT == MVT::f32) {
1085 if (Subtarget->isSingleFloat())
1086 return make_vector<unsigned>(Mips::F2, Mips::F3, Mips::F4, Mips::F5,
1087 Mips::F6, Mips::F7, Mips::F8, Mips::F9, Mips::F10, Mips::F11,
1088 Mips::F20, Mips::F21, Mips::F22, Mips::F23, Mips::F24,
1089 Mips::F25, Mips::F26, Mips::F27, Mips::F28, Mips::F29,
1090 Mips::F30, Mips::F31, 0);
1092 return make_vector<unsigned>(Mips::F2, Mips::F4, Mips::F6, Mips::F8,
1093 Mips::F10, Mips::F20, Mips::F22, Mips::F24, Mips::F26,
1094 Mips::F28, Mips::F30, 0);
1098 if ((!Subtarget->isSingleFloat()) && (!Subtarget->isFP64bit()))
1099 return make_vector<unsigned>(Mips::D1, Mips::D2, Mips::D3, Mips::D4,
1100 Mips::D5, Mips::D10, Mips::D11, Mips::D12, Mips::D13,
1101 Mips::D14, Mips::D15, 0);
1103 return std::vector<unsigned>();
1107 MipsTargetLowering::isOffsetFoldingLegal(const GlobalAddressSDNode *GA) const {
1108 // The Mips target isn't yet aware of offsets.