1 //===-- MBlazeISelDAGToDAG.cpp - A dag to dag inst selector for MBlaze ----===//
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 an instruction selector for the MBlaze target.
12 //===----------------------------------------------------------------------===//
14 #define DEBUG_TYPE "mblaze-isel"
16 #include "MBlazeMachineFunction.h"
17 #include "MBlazeRegisterInfo.h"
18 #include "MBlazeSubtarget.h"
19 #include "MBlazeTargetMachine.h"
20 #include "llvm/GlobalValue.h"
21 #include "llvm/Instructions.h"
22 #include "llvm/Intrinsics.h"
23 #include "llvm/Support/CFG.h"
24 #include "llvm/Type.h"
25 #include "llvm/CodeGen/MachineConstantPool.h"
26 #include "llvm/CodeGen/MachineFunction.h"
27 #include "llvm/CodeGen/MachineFrameInfo.h"
28 #include "llvm/CodeGen/MachineInstrBuilder.h"
29 #include "llvm/CodeGen/MachineRegisterInfo.h"
30 #include "llvm/CodeGen/SelectionDAGISel.h"
31 #include "llvm/Target/TargetMachine.h"
32 #include "llvm/Support/Debug.h"
33 #include "llvm/Support/ErrorHandling.h"
34 #include "llvm/Support/raw_ostream.h"
37 //===----------------------------------------------------------------------===//
38 // Instruction Selector Implementation
39 //===----------------------------------------------------------------------===//
41 //===----------------------------------------------------------------------===//
42 // MBlazeDAGToDAGISel - MBlaze specific code to select MBlaze machine
43 // instructions for SelectionDAG operations.
44 //===----------------------------------------------------------------------===//
47 class MBlazeDAGToDAGISel : public SelectionDAGISel {
49 /// TM - Keep a reference to MBlazeTargetMachine.
50 MBlazeTargetMachine &TM;
52 /// Subtarget - Keep a pointer to the MBlazeSubtarget around so that we can
53 /// make the right decision when generating code for different targets.
54 const MBlazeSubtarget &Subtarget;
57 explicit MBlazeDAGToDAGISel(MBlazeTargetMachine &tm) :
59 TM(tm), Subtarget(tm.getSubtarget<MBlazeSubtarget>()) {}
62 virtual const char *getPassName() const {
63 return "MBlaze DAG->DAG Pattern Instruction Selection";
66 // Include the pieces autogenerated from the target description.
67 #include "MBlazeGenDAGISel.inc"
69 /// getTargetMachine - Return a reference to the TargetMachine, casted
70 /// to the target-specific type.
71 const MBlazeTargetMachine &getTargetMachine() {
72 return static_cast<const MBlazeTargetMachine &>(TM);
75 /// getInstrInfo - Return a reference to the TargetInstrInfo, casted
76 /// to the target-specific type.
77 const MBlazeInstrInfo *getInstrInfo() {
78 return getTargetMachine().getInstrInfo();
81 SDNode *getGlobalBaseReg();
82 SDNode *Select(SDNode *N);
85 bool SelectAddr(SDNode *Op, SDValue N,
86 SDValue &Base, SDValue &Offset);
89 bool SelectAddrRegReg(SDNode *Op, SDValue N, SDValue &Base, SDValue &Index);
90 bool SelectAddrRegImm(SDNode *Op, SDValue N, SDValue &Disp, SDValue &Base);
92 // getI32Imm - Return a target constant with the specified value, of type i32.
93 inline SDValue getI32Imm(unsigned Imm) {
94 return CurDAG->getTargetConstant(Imm, MVT::i32);
100 /// isIntS32Immediate - This method tests to see if the node is either a 32-bit
101 /// or 64-bit immediate, and if the value can be accurately represented as a
102 /// sign extension from a 32-bit value. If so, this returns true and the
104 static bool isIntS32Immediate(SDNode *N, int32_t &Imm) {
105 unsigned Opc = N->getOpcode();
106 if (Opc != ISD::Constant)
109 Imm = (int32_t)cast<ConstantSDNode>(N)->getZExtValue();
110 if (N->getValueType(0) == MVT::i32)
111 return Imm == (int32_t)cast<ConstantSDNode>(N)->getZExtValue();
113 return Imm == (int64_t)cast<ConstantSDNode>(N)->getZExtValue();
116 static bool isIntS32Immediate(SDValue Op, int32_t &Imm) {
117 return isIntS32Immediate(Op.getNode(), Imm);
121 /// SelectAddressRegReg - Given the specified addressed, check to see if it
122 /// can be represented as an indexed [r+r] operation. Returns false if it
123 /// can be more efficiently represented with [r+imm].
124 bool MBlazeDAGToDAGISel::
125 SelectAddrRegReg(SDNode *Op, SDValue N, SDValue &Base, SDValue &Index) {
126 if (N.getOpcode() == ISD::FrameIndex) return false;
127 if (N.getOpcode() == ISD::TargetExternalSymbol ||
128 N.getOpcode() == ISD::TargetGlobalAddress)
129 return false; // direct calls.
132 if (N.getOpcode() == ISD::ADD || N.getOpcode() == ISD::OR) {
133 if (isIntS32Immediate(N.getOperand(1), imm))
136 if (N.getOperand(0).getOpcode() == ISD::TargetJumpTable ||
137 N.getOperand(1).getOpcode() == ISD::TargetJumpTable)
138 return false; // jump tables.
140 Base = N.getOperand(1);
141 Index = N.getOperand(0);
148 /// Returns true if the address N can be represented by a base register plus
149 /// a signed 32-bit displacement [r+imm], and if it is not better
150 /// represented as reg+reg.
151 bool MBlazeDAGToDAGISel::
152 SelectAddrRegImm(SDNode *Op, SDValue N, SDValue &Disp, SDValue &Base) {
153 // If this can be more profitably realized as r+r, fail.
154 if (SelectAddrRegReg(Op, N, Disp, Base))
157 if (N.getOpcode() == ISD::ADD || N.getOpcode() == ISD::OR) {
159 if (isIntS32Immediate(N.getOperand(1), imm)) {
160 Disp = CurDAG->getTargetConstant(imm, MVT::i32);
161 if (FrameIndexSDNode *FI = dyn_cast<FrameIndexSDNode>(N.getOperand(0))) {
162 Base = CurDAG->getTargetFrameIndex(FI->getIndex(), N.getValueType());
164 Base = N.getOperand(0);
166 DEBUG( errs() << "WESLEY: Using Operand Immediate\n" );
167 return true; // [r+i]
169 } else if (ConstantSDNode *CN = dyn_cast<ConstantSDNode>(N)) {
170 // Loading from a constant address.
171 uint32_t Imm = CN->getZExtValue();
172 Disp = CurDAG->getTargetConstant(Imm, CN->getValueType(0));
173 Base = CurDAG->getRegister(MBlaze::R0, CN->getValueType(0));
174 DEBUG( errs() << "WESLEY: Using Constant Node\n" );
178 Disp = CurDAG->getTargetConstant(0, TM.getTargetLowering()->getPointerTy());
179 if (FrameIndexSDNode *FI = dyn_cast<FrameIndexSDNode>(N))
180 Base = CurDAG->getTargetFrameIndex(FI->getIndex(), N.getValueType());
183 return true; // [r+0]
186 /// getGlobalBaseReg - Output the instructions required to put the
187 /// GOT address into a register.
188 SDNode *MBlazeDAGToDAGISel::getGlobalBaseReg() {
189 unsigned GlobalBaseReg = getInstrInfo()->getGlobalBaseReg(MF);
190 return CurDAG->getRegister(GlobalBaseReg, TLI.getPointerTy()).getNode();
193 /// ComplexPattern used on MBlazeInstrInfo
194 /// Used on MBlaze Load/Store instructions
195 bool MBlazeDAGToDAGISel::
196 SelectAddr(SDNode *Op, SDValue Addr, SDValue &Offset, SDValue &Base) {
197 // if Address is FI, get the TargetFrameIndex.
198 if (FrameIndexSDNode *FIN = dyn_cast<FrameIndexSDNode>(Addr)) {
199 Base = CurDAG->getTargetFrameIndex(FIN->getIndex(), MVT::i32);
200 Offset = CurDAG->getTargetConstant(0, MVT::i32);
204 // on PIC code Load GA
205 if (TM.getRelocationModel() == Reloc::PIC_) {
206 if ((Addr.getOpcode() == ISD::TargetGlobalAddress) ||
207 (Addr.getOpcode() == ISD::TargetConstantPool) ||
208 (Addr.getOpcode() == ISD::TargetJumpTable)){
209 Base = CurDAG->getRegister(MBlaze::R15, MVT::i32);
214 if ((Addr.getOpcode() == ISD::TargetExternalSymbol ||
215 Addr.getOpcode() == ISD::TargetGlobalAddress))
219 // Operand is a result from an ADD.
220 if (Addr.getOpcode() == ISD::ADD) {
221 if (ConstantSDNode *CN = dyn_cast<ConstantSDNode>(Addr.getOperand(1))) {
222 if (Predicate_immSExt16(CN)) {
224 // If the first operand is a FI, get the TargetFI Node
225 if (FrameIndexSDNode *FIN = dyn_cast<FrameIndexSDNode>
226 (Addr.getOperand(0))) {
227 Base = CurDAG->getTargetFrameIndex(FIN->getIndex(), MVT::i32);
229 Base = Addr.getOperand(0);
232 Offset = CurDAG->getTargetConstant(CN->getZExtValue(), MVT::i32);
239 Offset = CurDAG->getTargetConstant(0, MVT::i32);
243 /// Select instructions not customized! Used for
244 /// expanded, promoted and normal instructions
245 SDNode* MBlazeDAGToDAGISel::Select(SDNode *Node) {
246 unsigned Opcode = Node->getOpcode();
247 DebugLoc dl = Node->getDebugLoc();
249 // Dump information about the Node being selected
250 DEBUG(errs() << "Selecting: "; Node->dump(CurDAG); errs() << "\n");
252 // If we have a custom node, we already have selected!
253 if (Node->isMachineOpcode()) {
254 DEBUG(errs() << "== "; Node->dump(CurDAG); errs() << "\n");
259 // Instruction Selection not handled by the auto-generated
260 // tablegen selection should be handled here.
265 // Get target GOT address.
266 case ISD::GLOBAL_OFFSET_TABLE:
267 return getGlobalBaseReg();
269 case ISD::FrameIndex: {
270 SDValue imm = CurDAG->getTargetConstant(0, MVT::i32);
271 int FI = dyn_cast<FrameIndexSDNode>(Node)->getIndex();
272 EVT VT = Node->getValueType(0);
273 SDValue TFI = CurDAG->getTargetFrameIndex(FI, VT);
274 unsigned Opc = MBlaze::ADDI;
275 if (Node->hasOneUse())
276 return CurDAG->SelectNodeTo(Node, Opc, VT, TFI, imm);
277 return CurDAG->getMachineNode(Opc, dl, VT, TFI, imm);
281 /// Handle direct and indirect calls when using PIC. On PIC, when
282 /// GOT is smaller than about 64k (small code) the GA target is
283 /// loaded with only one instruction. Otherwise GA's target must
284 /// be loaded with 3 instructions.
285 case MBlazeISD::JmpLink: {
286 if (TM.getRelocationModel() == Reloc::PIC_) {
287 SDValue Chain = Node->getOperand(0);
288 SDValue Callee = Node->getOperand(1);
289 SDValue R20Reg = CurDAG->getRegister(MBlaze::R20, MVT::i32);
290 SDValue InFlag(0, 0);
292 if ( (isa<GlobalAddressSDNode>(Callee)) ||
293 (isa<ExternalSymbolSDNode>(Callee)) )
295 /// Direct call for global addresses and external symbols
296 SDValue GPReg = CurDAG->getRegister(MBlaze::R15, MVT::i32);
298 // Use load to get GOT target
299 SDValue Ops[] = { Callee, GPReg, Chain };
300 SDValue Load = SDValue(CurDAG->getMachineNode(MBlaze::LW, dl,
301 MVT::i32, MVT::Other, Ops, 3), 0);
302 Chain = Load.getValue(1);
304 // Call target must be on T9
305 Chain = CurDAG->getCopyToReg(Chain, dl, R20Reg, Load, InFlag);
308 Chain = CurDAG->getCopyToReg(Chain, dl, R20Reg, Callee, InFlag);
310 // Emit Jump and Link Register
311 SDNode *ResNode = CurDAG->getMachineNode(MBlaze::BRLID, dl, MVT::Other,
312 MVT::Flag, R20Reg, Chain);
313 Chain = SDValue(ResNode, 0);
314 InFlag = SDValue(ResNode, 1);
315 ReplaceUses(SDValue(Node, 0), Chain);
316 ReplaceUses(SDValue(Node, 1), InFlag);
322 // Select the default instruction
323 SDNode *ResNode = SelectCode(Node);
325 DEBUG(errs() << "=> ");
326 if (ResNode == NULL || ResNode == Node)
327 DEBUG(Node->dump(CurDAG));
329 DEBUG(ResNode->dump(CurDAG));
330 DEBUG(errs() << "\n");
334 /// createMBlazeISelDag - This pass converts a legalized DAG into a
335 /// MBlaze-specific DAG, ready for instruction scheduling.
336 FunctionPass *llvm::createMBlazeISelDag(MBlazeTargetMachine &TM) {
337 return new MBlazeDAGToDAGISel(TM);