1 //===-- MSP430ISelDAGToDAG.cpp - A dag to dag inst selector for MSP430 ----===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // This file defines an instruction selector for the MSP430 target.
10 //
11 //===----------------------------------------------------------------------===//
12
13 #include "MSP430.h"
14 #include "MSP430TargetMachine.h"
15 #include "llvm/CodeGen/MachineFrameInfo.h"
16 #include "llvm/CodeGen/MachineFunction.h"
17 #include "llvm/CodeGen/MachineInstrBuilder.h"
18 #include "llvm/CodeGen/MachineRegisterInfo.h"
19 #include "llvm/CodeGen/SelectionDAG.h"
20 #include "llvm/CodeGen/SelectionDAGISel.h"
21 #include "llvm/Config/llvm-config.h"
22 #include "llvm/IR/CallingConv.h"
23 #include "llvm/IR/Constants.h"
24 #include "llvm/IR/DerivedTypes.h"
25 #include "llvm/IR/Function.h"
26 #include "llvm/IR/Intrinsics.h"
27 #include "llvm/Support/Debug.h"
28 #include "llvm/Support/ErrorHandling.h"
29 #include "llvm/Support/raw_ostream.h"
30 using namespace llvm;
31
32 #define DEBUG_TYPE "msp430-isel"
33 #define PASS_NAME "MSP430 DAG->DAG Pattern Instruction Selection"
34
35 namespace {
36 struct MSP430ISelAddressMode {
37 enum {
38 RegBase,
39 FrameIndexBase
40 } BaseType = RegBase;
41
42 struct { // This is really a union, discriminated by BaseType!
43 SDValue Reg;
44 int FrameIndex = 0;
45 } Base;
46
47 int16_t Disp = 0;
48 const GlobalValue *GV = nullptr;
49 const Constant *CP = nullptr;
50 const BlockAddress *BlockAddr = nullptr;
51 const char *ES = nullptr;
52 int JT = -1;
53 Align Alignment; // CP alignment.
54
55 MSP430ISelAddressMode() = default;
56
hasSymbolicDisplacement__anondc37b0cb0111::MSP430ISelAddressMode57 bool hasSymbolicDisplacement() const {
58 return GV != nullptr || CP != nullptr || ES != nullptr || JT != -1;
59 }
60
61 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
dump__anondc37b0cb0111::MSP430ISelAddressMode62 LLVM_DUMP_METHOD void dump() {
63 errs() << "MSP430ISelAddressMode " << this << '\n';
64 if (BaseType == RegBase && Base.Reg.getNode() != nullptr) {
65 errs() << "Base.Reg ";
66 Base.Reg.getNode()->dump();
67 } else if (BaseType == FrameIndexBase) {
68 errs() << " Base.FrameIndex " << Base.FrameIndex << '\n';
69 }
70 errs() << " Disp " << Disp << '\n';
71 if (GV) {
72 errs() << "GV ";
73 GV->dump();
74 } else if (CP) {
75 errs() << " CP ";
76 CP->dump();
77 errs() << " Align" << Alignment.value() << '\n';
78 } else if (ES) {
79 errs() << "ES ";
80 errs() << ES << '\n';
81 } else if (JT != -1)
82 errs() << " JT" << JT << " Align" << Alignment.value() << '\n';
83 }
84 #endif
85 };
86 }
87
88 /// MSP430DAGToDAGISel - MSP430 specific code to select MSP430 machine
89 /// instructions for SelectionDAG operations.
90 ///
91 namespace {
92 class MSP430DAGToDAGISel : public SelectionDAGISel {
93 public:
94 MSP430DAGToDAGISel() = delete;
95
MSP430DAGToDAGISel(MSP430TargetMachine & TM,CodeGenOptLevel OptLevel)96 MSP430DAGToDAGISel(MSP430TargetMachine &TM, CodeGenOptLevel OptLevel)
97 : SelectionDAGISel(TM, OptLevel) {}
98
99 private:
100 bool MatchAddress(SDValue N, MSP430ISelAddressMode &AM);
101 bool MatchWrapper(SDValue N, MSP430ISelAddressMode &AM);
102 bool MatchAddressBase(SDValue N, MSP430ISelAddressMode &AM);
103
104 bool SelectInlineAsmMemoryOperand(const SDValue &Op,
105 InlineAsm::ConstraintCode ConstraintID,
106 std::vector<SDValue> &OutOps) override;
107
108 // Include the pieces autogenerated from the target description.
109 #include "MSP430GenDAGISel.inc"
110
111 // Main method to transform nodes into machine nodes.
112 void Select(SDNode *N) override;
113
114 bool tryIndexedLoad(SDNode *Op);
115 bool tryIndexedBinOp(SDNode *Op, SDValue N1, SDValue N2, unsigned Opc8,
116 unsigned Opc16);
117
118 bool SelectAddr(SDValue Addr, SDValue &Base, SDValue &Disp);
119 };
120
121 class MSP430DAGToDAGISelLegacy : public SelectionDAGISelLegacy {
122 public:
123 static char ID;
MSP430DAGToDAGISelLegacy(MSP430TargetMachine & TM,CodeGenOptLevel OptLevel)124 MSP430DAGToDAGISelLegacy(MSP430TargetMachine &TM, CodeGenOptLevel OptLevel)
125 : SelectionDAGISelLegacy(
126 ID, std::make_unique<MSP430DAGToDAGISel>(TM, OptLevel)) {}
127 };
128 } // end anonymous namespace
129
130 char MSP430DAGToDAGISelLegacy::ID;
131
INITIALIZE_PASS(MSP430DAGToDAGISelLegacy,DEBUG_TYPE,PASS_NAME,false,false)132 INITIALIZE_PASS(MSP430DAGToDAGISelLegacy, DEBUG_TYPE, PASS_NAME, false, false)
133
134 /// createMSP430ISelDag - This pass converts a legalized DAG into a
135 /// MSP430-specific DAG, ready for instruction scheduling.
136 ///
137 FunctionPass *llvm::createMSP430ISelDag(MSP430TargetMachine &TM,
138 CodeGenOptLevel OptLevel) {
139 return new MSP430DAGToDAGISelLegacy(TM, OptLevel);
140 }
141
142 /// MatchWrapper - Try to match MSP430ISD::Wrapper node into an addressing mode.
143 /// These wrap things that will resolve down into a symbol reference. If no
144 /// match is possible, this returns true, otherwise it returns false.
MatchWrapper(SDValue N,MSP430ISelAddressMode & AM)145 bool MSP430DAGToDAGISel::MatchWrapper(SDValue N, MSP430ISelAddressMode &AM) {
146 // If the addressing mode already has a symbol as the displacement, we can
147 // never match another symbol.
148 if (AM.hasSymbolicDisplacement())
149 return true;
150
151 SDValue N0 = N.getOperand(0);
152
153 if (GlobalAddressSDNode *G = dyn_cast<GlobalAddressSDNode>(N0)) {
154 AM.GV = G->getGlobal();
155 AM.Disp += G->getOffset();
156 //AM.SymbolFlags = G->getTargetFlags();
157 } else if (ConstantPoolSDNode *CP = dyn_cast<ConstantPoolSDNode>(N0)) {
158 AM.CP = CP->getConstVal();
159 AM.Alignment = CP->getAlign();
160 AM.Disp += CP->getOffset();
161 //AM.SymbolFlags = CP->getTargetFlags();
162 } else if (ExternalSymbolSDNode *S = dyn_cast<ExternalSymbolSDNode>(N0)) {
163 AM.ES = S->getSymbol();
164 //AM.SymbolFlags = S->getTargetFlags();
165 } else if (JumpTableSDNode *J = dyn_cast<JumpTableSDNode>(N0)) {
166 AM.JT = J->getIndex();
167 //AM.SymbolFlags = J->getTargetFlags();
168 } else {
169 AM.BlockAddr = cast<BlockAddressSDNode>(N0)->getBlockAddress();
170 //AM.SymbolFlags = cast<BlockAddressSDNode>(N0)->getTargetFlags();
171 }
172 return false;
173 }
174
175 /// MatchAddressBase - Helper for MatchAddress. Add the specified node to the
176 /// specified addressing mode without any further recursion.
MatchAddressBase(SDValue N,MSP430ISelAddressMode & AM)177 bool MSP430DAGToDAGISel::MatchAddressBase(SDValue N, MSP430ISelAddressMode &AM) {
178 // Is the base register already occupied?
179 if (AM.BaseType != MSP430ISelAddressMode::RegBase || AM.Base.Reg.getNode()) {
180 // If so, we cannot select it.
181 return true;
182 }
183
184 // Default, generate it as a register.
185 AM.BaseType = MSP430ISelAddressMode::RegBase;
186 AM.Base.Reg = N;
187 return false;
188 }
189
MatchAddress(SDValue N,MSP430ISelAddressMode & AM)190 bool MSP430DAGToDAGISel::MatchAddress(SDValue N, MSP430ISelAddressMode &AM) {
191 LLVM_DEBUG(errs() << "MatchAddress: "; AM.dump());
192
193 switch (N.getOpcode()) {
194 default: break;
195 case ISD::Constant: {
196 uint64_t Val = cast<ConstantSDNode>(N)->getSExtValue();
197 AM.Disp += Val;
198 return false;
199 }
200
201 case MSP430ISD::Wrapper:
202 if (!MatchWrapper(N, AM))
203 return false;
204 break;
205
206 case ISD::FrameIndex:
207 if (AM.BaseType == MSP430ISelAddressMode::RegBase
208 && AM.Base.Reg.getNode() == nullptr) {
209 AM.BaseType = MSP430ISelAddressMode::FrameIndexBase;
210 AM.Base.FrameIndex = cast<FrameIndexSDNode>(N)->getIndex();
211 return false;
212 }
213 break;
214
215 case ISD::ADD: {
216 MSP430ISelAddressMode Backup = AM;
217 if (!MatchAddress(N.getNode()->getOperand(0), AM) &&
218 !MatchAddress(N.getNode()->getOperand(1), AM))
219 return false;
220 AM = Backup;
221 if (!MatchAddress(N.getNode()->getOperand(1), AM) &&
222 !MatchAddress(N.getNode()->getOperand(0), AM))
223 return false;
224 AM = Backup;
225
226 break;
227 }
228
229 case ISD::OR:
230 // Handle "X | C" as "X + C" iff X is known to have C bits clear.
231 if (ConstantSDNode *CN = dyn_cast<ConstantSDNode>(N.getOperand(1))) {
232 MSP430ISelAddressMode Backup = AM;
233 uint64_t Offset = CN->getSExtValue();
234 // Start with the LHS as an addr mode.
235 if (!MatchAddress(N.getOperand(0), AM) &&
236 // Address could not have picked a GV address for the displacement.
237 AM.GV == nullptr &&
238 // Check to see if the LHS & C is zero.
239 CurDAG->MaskedValueIsZero(N.getOperand(0), CN->getAPIntValue())) {
240 AM.Disp += Offset;
241 return false;
242 }
243 AM = Backup;
244 }
245 break;
246 }
247
248 return MatchAddressBase(N, AM);
249 }
250
251 /// SelectAddr - returns true if it is able pattern match an addressing mode.
252 /// It returns the operands which make up the maximal addressing mode it can
253 /// match by reference.
SelectAddr(SDValue N,SDValue & Base,SDValue & Disp)254 bool MSP430DAGToDAGISel::SelectAddr(SDValue N,
255 SDValue &Base, SDValue &Disp) {
256 MSP430ISelAddressMode AM;
257
258 if (MatchAddress(N, AM))
259 return false;
260
261 if (AM.BaseType == MSP430ISelAddressMode::RegBase)
262 if (!AM.Base.Reg.getNode())
263 AM.Base.Reg = CurDAG->getRegister(MSP430::SR, MVT::i16);
264
265 Base = (AM.BaseType == MSP430ISelAddressMode::FrameIndexBase)
266 ? CurDAG->getTargetFrameIndex(
267 AM.Base.FrameIndex,
268 N.getValueType())
269 : AM.Base.Reg;
270
271 if (AM.GV)
272 Disp = CurDAG->getTargetGlobalAddress(AM.GV, SDLoc(N),
273 MVT::i16, AM.Disp,
274 0/*AM.SymbolFlags*/);
275 else if (AM.CP)
276 Disp = CurDAG->getTargetConstantPool(AM.CP, MVT::i16, AM.Alignment, AM.Disp,
277 0 /*AM.SymbolFlags*/);
278 else if (AM.ES)
279 Disp = CurDAG->getTargetExternalSymbol(AM.ES, MVT::i16, 0/*AM.SymbolFlags*/);
280 else if (AM.JT != -1)
281 Disp = CurDAG->getTargetJumpTable(AM.JT, MVT::i16, 0/*AM.SymbolFlags*/);
282 else if (AM.BlockAddr)
283 Disp = CurDAG->getTargetBlockAddress(AM.BlockAddr, MVT::i32, 0,
284 0/*AM.SymbolFlags*/);
285 else
286 Disp = CurDAG->getTargetConstant(AM.Disp, SDLoc(N), MVT::i16);
287
288 return true;
289 }
290
SelectInlineAsmMemoryOperand(const SDValue & Op,InlineAsm::ConstraintCode ConstraintID,std::vector<SDValue> & OutOps)291 bool MSP430DAGToDAGISel::SelectInlineAsmMemoryOperand(
292 const SDValue &Op, InlineAsm::ConstraintCode ConstraintID,
293 std::vector<SDValue> &OutOps) {
294 SDValue Op0, Op1;
295 switch (ConstraintID) {
296 default: return true;
297 case InlineAsm::ConstraintCode::m: // memory
298 if (!SelectAddr(Op, Op0, Op1))
299 return true;
300 break;
301 }
302
303 OutOps.push_back(Op0);
304 OutOps.push_back(Op1);
305 return false;
306 }
307
isValidIndexedLoad(const LoadSDNode * LD)308 static bool isValidIndexedLoad(const LoadSDNode *LD) {
309 ISD::MemIndexedMode AM = LD->getAddressingMode();
310 if (AM != ISD::POST_INC || LD->getExtensionType() != ISD::NON_EXTLOAD)
311 return false;
312
313 EVT VT = LD->getMemoryVT();
314
315 switch (VT.getSimpleVT().SimpleTy) {
316 case MVT::i8:
317 if (LD->getOffset()->getAsZExtVal() != 1)
318 return false;
319
320 break;
321 case MVT::i16:
322 if (LD->getOffset()->getAsZExtVal() != 2)
323 return false;
324
325 break;
326 default:
327 return false;
328 }
329
330 return true;
331 }
332
tryIndexedLoad(SDNode * N)333 bool MSP430DAGToDAGISel::tryIndexedLoad(SDNode *N) {
334 LoadSDNode *LD = cast<LoadSDNode>(N);
335 if (!isValidIndexedLoad(LD))
336 return false;
337
338 MVT VT = LD->getMemoryVT().getSimpleVT();
339
340 unsigned Opcode = 0;
341 switch (VT.SimpleTy) {
342 case MVT::i8:
343 Opcode = MSP430::MOV8rp;
344 break;
345 case MVT::i16:
346 Opcode = MSP430::MOV16rp;
347 break;
348 default:
349 return false;
350 }
351
352 ReplaceNode(N,
353 CurDAG->getMachineNode(Opcode, SDLoc(N), VT, MVT::i16, MVT::Other,
354 LD->getBasePtr(), LD->getChain()));
355 return true;
356 }
357
tryIndexedBinOp(SDNode * Op,SDValue N1,SDValue N2,unsigned Opc8,unsigned Opc16)358 bool MSP430DAGToDAGISel::tryIndexedBinOp(SDNode *Op, SDValue N1, SDValue N2,
359 unsigned Opc8, unsigned Opc16) {
360 if (N1.getOpcode() == ISD::LOAD &&
361 N1.hasOneUse() &&
362 IsLegalToFold(N1, Op, Op, OptLevel)) {
363 LoadSDNode *LD = cast<LoadSDNode>(N1);
364 if (!isValidIndexedLoad(LD))
365 return false;
366
367 MVT VT = LD->getMemoryVT().getSimpleVT();
368 unsigned Opc = (VT == MVT::i16 ? Opc16 : Opc8);
369 MachineMemOperand *MemRef = cast<MemSDNode>(N1)->getMemOperand();
370 SDValue Ops0[] = { N2, LD->getBasePtr(), LD->getChain() };
371 SDNode *ResNode =
372 CurDAG->SelectNodeTo(Op, Opc, VT, MVT::i16, MVT::Other, Ops0);
373 CurDAG->setNodeMemRefs(cast<MachineSDNode>(ResNode), {MemRef});
374 // Transfer chain.
375 ReplaceUses(SDValue(N1.getNode(), 2), SDValue(ResNode, 2));
376 // Transfer writeback.
377 ReplaceUses(SDValue(N1.getNode(), 1), SDValue(ResNode, 1));
378 return true;
379 }
380
381 return false;
382 }
383
384
Select(SDNode * Node)385 void MSP430DAGToDAGISel::Select(SDNode *Node) {
386 SDLoc dl(Node);
387
388 // If we have a custom node, we already have selected!
389 if (Node->isMachineOpcode()) {
390 LLVM_DEBUG(errs() << "== "; Node->dump(CurDAG); errs() << "\n");
391 Node->setNodeId(-1);
392 return;
393 }
394
395 // Few custom selection stuff.
396 switch (Node->getOpcode()) {
397 default: break;
398 case ISD::FrameIndex: {
399 assert(Node->getValueType(0) == MVT::i16);
400 int FI = cast<FrameIndexSDNode>(Node)->getIndex();
401 SDValue TFI = CurDAG->getTargetFrameIndex(FI, MVT::i16);
402 if (Node->hasOneUse()) {
403 CurDAG->SelectNodeTo(Node, MSP430::ADDframe, MVT::i16, TFI,
404 CurDAG->getTargetConstant(0, dl, MVT::i16));
405 return;
406 }
407 ReplaceNode(Node, CurDAG->getMachineNode(
408 MSP430::ADDframe, dl, MVT::i16, TFI,
409 CurDAG->getTargetConstant(0, dl, MVT::i16)));
410 return;
411 }
412 case ISD::LOAD:
413 if (tryIndexedLoad(Node))
414 return;
415 // Other cases are autogenerated.
416 break;
417 case ISD::ADD:
418 if (tryIndexedBinOp(Node, Node->getOperand(0), Node->getOperand(1),
419 MSP430::ADD8rp, MSP430::ADD16rp))
420 return;
421 else if (tryIndexedBinOp(Node, Node->getOperand(1), Node->getOperand(0),
422 MSP430::ADD8rp, MSP430::ADD16rp))
423 return;
424
425 // Other cases are autogenerated.
426 break;
427 case ISD::SUB:
428 if (tryIndexedBinOp(Node, Node->getOperand(0), Node->getOperand(1),
429 MSP430::SUB8rp, MSP430::SUB16rp))
430 return;
431
432 // Other cases are autogenerated.
433 break;
434 case ISD::AND:
435 if (tryIndexedBinOp(Node, Node->getOperand(0), Node->getOperand(1),
436 MSP430::AND8rp, MSP430::AND16rp))
437 return;
438 else if (tryIndexedBinOp(Node, Node->getOperand(1), Node->getOperand(0),
439 MSP430::AND8rp, MSP430::AND16rp))
440 return;
441
442 // Other cases are autogenerated.
443 break;
444 case ISD::OR:
445 if (tryIndexedBinOp(Node, Node->getOperand(0), Node->getOperand(1),
446 MSP430::BIS8rp, MSP430::BIS16rp))
447 return;
448 else if (tryIndexedBinOp(Node, Node->getOperand(1), Node->getOperand(0),
449 MSP430::BIS8rp, MSP430::BIS16rp))
450 return;
451
452 // Other cases are autogenerated.
453 break;
454 case ISD::XOR:
455 if (tryIndexedBinOp(Node, Node->getOperand(0), Node->getOperand(1),
456 MSP430::XOR8rp, MSP430::XOR16rp))
457 return;
458 else if (tryIndexedBinOp(Node, Node->getOperand(1), Node->getOperand(0),
459 MSP430::XOR8rp, MSP430::XOR16rp))
460 return;
461
462 // Other cases are autogenerated.
463 break;
464 }
465
466 // Select the default instruction
467 SelectCode(Node);
468 }
469