1 //===- VEDisassembler.cpp - Disassembler for VE -----------------*- C++ -*-===//
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 is part of the VE Disassembler.
10 //
11 //===----------------------------------------------------------------------===//
12 
13 #include "MCTargetDesc/VEMCTargetDesc.h"
14 #include "TargetInfo/VETargetInfo.h"
15 #include "VE.h"
16 #include "llvm/MC/MCAsmInfo.h"
17 #include "llvm/MC/MCContext.h"
18 #include "llvm/MC/MCDisassembler/MCDisassembler.h"
19 #include "llvm/MC/MCFixedLenDisassembler.h"
20 #include "llvm/MC/MCInst.h"
21 #include "llvm/Support/TargetRegistry.h"
22 
23 using namespace llvm;
24 
25 #define DEBUG_TYPE "ve-disassembler"
26 
27 typedef MCDisassembler::DecodeStatus DecodeStatus;
28 
29 namespace {
30 
31 /// A disassembler class for VE.
32 class VEDisassembler : public MCDisassembler {
33 public:
34   VEDisassembler(const MCSubtargetInfo &STI, MCContext &Ctx)
35       : MCDisassembler(STI, Ctx) {}
36   virtual ~VEDisassembler() {}
37 
38   DecodeStatus getInstruction(MCInst &Instr, uint64_t &Size,
39                               ArrayRef<uint8_t> Bytes, uint64_t Address,
40                               raw_ostream &CStream) const override;
41 };
42 } // namespace
43 
44 static MCDisassembler *createVEDisassembler(const Target &T,
45                                             const MCSubtargetInfo &STI,
46                                             MCContext &Ctx) {
47   return new VEDisassembler(STI, Ctx);
48 }
49 
50 extern "C" void LLVMInitializeVEDisassembler() {
51   // Register the disassembler.
52   TargetRegistry::RegisterMCDisassembler(getTheVETarget(),
53                                          createVEDisassembler);
54 }
55 
56 static const unsigned I32RegDecoderTable[] = {
57     VE::SW0,  VE::SW1,  VE::SW2,  VE::SW3,  VE::SW4,  VE::SW5,  VE::SW6,
58     VE::SW7,  VE::SW8,  VE::SW9,  VE::SW10, VE::SW11, VE::SW12, VE::SW13,
59     VE::SW14, VE::SW15, VE::SW16, VE::SW17, VE::SW18, VE::SW19, VE::SW20,
60     VE::SW21, VE::SW22, VE::SW23, VE::SW24, VE::SW25, VE::SW26, VE::SW27,
61     VE::SW28, VE::SW29, VE::SW30, VE::SW31, VE::SW32, VE::SW33, VE::SW34,
62     VE::SW35, VE::SW36, VE::SW37, VE::SW38, VE::SW39, VE::SW40, VE::SW41,
63     VE::SW42, VE::SW43, VE::SW44, VE::SW45, VE::SW46, VE::SW47, VE::SW48,
64     VE::SW49, VE::SW50, VE::SW51, VE::SW52, VE::SW53, VE::SW54, VE::SW55,
65     VE::SW56, VE::SW57, VE::SW58, VE::SW59, VE::SW60, VE::SW61, VE::SW62,
66     VE::SW63};
67 
68 static const unsigned I64RegDecoderTable[] = {
69     VE::SX0,  VE::SX1,  VE::SX2,  VE::SX3,  VE::SX4,  VE::SX5,  VE::SX6,
70     VE::SX7,  VE::SX8,  VE::SX9,  VE::SX10, VE::SX11, VE::SX12, VE::SX13,
71     VE::SX14, VE::SX15, VE::SX16, VE::SX17, VE::SX18, VE::SX19, VE::SX20,
72     VE::SX21, VE::SX22, VE::SX23, VE::SX24, VE::SX25, VE::SX26, VE::SX27,
73     VE::SX28, VE::SX29, VE::SX30, VE::SX31, VE::SX32, VE::SX33, VE::SX34,
74     VE::SX35, VE::SX36, VE::SX37, VE::SX38, VE::SX39, VE::SX40, VE::SX41,
75     VE::SX42, VE::SX43, VE::SX44, VE::SX45, VE::SX46, VE::SX47, VE::SX48,
76     VE::SX49, VE::SX50, VE::SX51, VE::SX52, VE::SX53, VE::SX54, VE::SX55,
77     VE::SX56, VE::SX57, VE::SX58, VE::SX59, VE::SX60, VE::SX61, VE::SX62,
78     VE::SX63};
79 
80 static const unsigned F32RegDecoderTable[] = {
81     VE::SF0,  VE::SF1,  VE::SF2,  VE::SF3,  VE::SF4,  VE::SF5,  VE::SF6,
82     VE::SF7,  VE::SF8,  VE::SF9,  VE::SF10, VE::SF11, VE::SF12, VE::SF13,
83     VE::SF14, VE::SF15, VE::SF16, VE::SF17, VE::SF18, VE::SF19, VE::SF20,
84     VE::SF21, VE::SF22, VE::SF23, VE::SF24, VE::SF25, VE::SF26, VE::SF27,
85     VE::SF28, VE::SF29, VE::SF30, VE::SF31, VE::SF32, VE::SF33, VE::SF34,
86     VE::SF35, VE::SF36, VE::SF37, VE::SF38, VE::SF39, VE::SF40, VE::SF41,
87     VE::SF42, VE::SF43, VE::SF44, VE::SF45, VE::SF46, VE::SF47, VE::SF48,
88     VE::SF49, VE::SF50, VE::SF51, VE::SF52, VE::SF53, VE::SF54, VE::SF55,
89     VE::SF56, VE::SF57, VE::SF58, VE::SF59, VE::SF60, VE::SF61, VE::SF62,
90     VE::SF63};
91 
92 static const unsigned MiscRegDecoderTable[] = {
93     VE::USRCC,      VE::PSW,        VE::SAR,        VE::NoRegister,
94     VE::NoRegister, VE::NoRegister, VE::NoRegister, VE::PMMR,
95     VE::PMCR0,      VE::PMCR1,      VE::PMCR2,      VE::PMCR3,
96     VE::NoRegister, VE::NoRegister, VE::NoRegister, VE::NoRegister,
97     VE::PMC0,       VE::PMC1,       VE::PMC2,       VE::PMC3,
98     VE::PMC4,       VE::PMC5,       VE::PMC6,       VE::PMC7,
99     VE::PMC8,       VE::PMC9,       VE::PMC10,      VE::PMC11,
100     VE::PMC12,      VE::PMC13,      VE::PMC14};
101 
102 static DecodeStatus DecodeI32RegisterClass(MCInst &Inst, unsigned RegNo,
103                                            uint64_t Address,
104                                            const void *Decoder) {
105   if (RegNo > 63)
106     return MCDisassembler::Fail;
107   unsigned Reg = I32RegDecoderTable[RegNo];
108   Inst.addOperand(MCOperand::createReg(Reg));
109   return MCDisassembler::Success;
110 }
111 
112 static DecodeStatus DecodeI64RegisterClass(MCInst &Inst, unsigned RegNo,
113                                            uint64_t Address,
114                                            const void *Decoder) {
115   if (RegNo > 63)
116     return MCDisassembler::Fail;
117   unsigned Reg = I64RegDecoderTable[RegNo];
118   Inst.addOperand(MCOperand::createReg(Reg));
119   return MCDisassembler::Success;
120 }
121 
122 static DecodeStatus DecodeF32RegisterClass(MCInst &Inst, unsigned RegNo,
123                                            uint64_t Address,
124                                            const void *Decoder) {
125   if (RegNo > 63)
126     return MCDisassembler::Fail;
127   unsigned Reg = F32RegDecoderTable[RegNo];
128   Inst.addOperand(MCOperand::createReg(Reg));
129   return MCDisassembler::Success;
130 }
131 
132 static DecodeStatus DecodeMISCRegisterClass(MCInst &Inst, unsigned RegNo,
133                                             uint64_t Address,
134                                             const void *Decoder) {
135   if (RegNo > 30)
136     return MCDisassembler::Fail;
137   unsigned Reg = MiscRegDecoderTable[RegNo];
138   if (Reg == VE::NoRegister)
139     return MCDisassembler::Fail;
140   Inst.addOperand(MCOperand::createReg(Reg));
141   return MCDisassembler::Success;
142 }
143 
144 static DecodeStatus DecodeLoadI32(MCInst &Inst, uint64_t insn, uint64_t Address,
145                                   const void *Decoder);
146 static DecodeStatus DecodeStoreI32(MCInst &Inst, uint64_t insn,
147                                    uint64_t Address, const void *Decoder);
148 static DecodeStatus DecodeLoadI64(MCInst &Inst, uint64_t insn, uint64_t Address,
149                                   const void *Decoder);
150 static DecodeStatus DecodeStoreI64(MCInst &Inst, uint64_t insn,
151                                    uint64_t Address, const void *Decoder);
152 static DecodeStatus DecodeLoadF32(MCInst &Inst, uint64_t insn, uint64_t Address,
153                                   const void *Decoder);
154 static DecodeStatus DecodeStoreF32(MCInst &Inst, uint64_t insn,
155                                    uint64_t Address, const void *Decoder);
156 static DecodeStatus DecodeCall(MCInst &Inst, uint64_t insn, uint64_t Address,
157                                const void *Decoder);
158 static DecodeStatus DecodeSIMM7(MCInst &Inst, uint64_t insn, uint64_t Address,
159                                 const void *Decoder);
160 static DecodeStatus DecodeCCOperand(MCInst &Inst, uint64_t insn,
161                                     uint64_t Address, const void *Decoder);
162 static DecodeStatus DecodeBranchCondition(MCInst &Inst, uint64_t insn,
163                                           uint64_t Address,
164                                           const void *Decoder);
165 static DecodeStatus DecodeBranchConditionAlways(MCInst &Inst, uint64_t insn,
166                                                 uint64_t Address,
167                                                 const void *Decoder);
168 
169 #include "VEGenDisassemblerTables.inc"
170 
171 /// Read four bytes from the ArrayRef and return 32 bit word.
172 static DecodeStatus readInstruction64(ArrayRef<uint8_t> Bytes, uint64_t Address,
173                                       uint64_t &Size, uint64_t &Insn,
174                                       bool IsLittleEndian) {
175   // We want to read exactly 8 Bytes of data.
176   if (Bytes.size() < 8) {
177     Size = 0;
178     return MCDisassembler::Fail;
179   }
180 
181   Insn = IsLittleEndian
182              ? ((uint64_t)Bytes[0] << 0) | ((uint64_t)Bytes[1] << 8) |
183                    ((uint64_t)Bytes[2] << 16) | ((uint64_t)Bytes[3] << 24) |
184                    ((uint64_t)Bytes[4] << 32) | ((uint64_t)Bytes[5] << 40) |
185                    ((uint64_t)Bytes[6] << 48) | ((uint64_t)Bytes[7] << 56)
186              : ((uint64_t)Bytes[7] << 0) | ((uint64_t)Bytes[6] << 8) |
187                    ((uint64_t)Bytes[5] << 16) | ((uint64_t)Bytes[4] << 24) |
188                    ((uint64_t)Bytes[3] << 32) | ((uint64_t)Bytes[2] << 40) |
189                    ((uint64_t)Bytes[1] << 48) | ((uint64_t)Bytes[0] << 56);
190 
191   return MCDisassembler::Success;
192 }
193 
194 DecodeStatus VEDisassembler::getInstruction(MCInst &Instr, uint64_t &Size,
195                                             ArrayRef<uint8_t> Bytes,
196                                             uint64_t Address,
197                                             raw_ostream &CStream) const {
198   uint64_t Insn;
199   bool isLittleEndian = getContext().getAsmInfo()->isLittleEndian();
200   DecodeStatus Result =
201       readInstruction64(Bytes, Address, Size, Insn, isLittleEndian);
202   if (Result == MCDisassembler::Fail)
203     return MCDisassembler::Fail;
204 
205   // Calling the auto-generated decoder function.
206 
207   Result = decodeInstruction(DecoderTableVE64, Instr, Insn, Address, this, STI);
208 
209   if (Result != MCDisassembler::Fail) {
210     Size = 8;
211     return Result;
212   }
213 
214   return MCDisassembler::Fail;
215 }
216 
217 typedef DecodeStatus (*DecodeFunc)(MCInst &MI, unsigned RegNo, uint64_t Address,
218                                    const void *Decoder);
219 
220 static DecodeStatus DecodeASX(MCInst &MI, uint64_t insn, uint64_t Address,
221                               const void *Decoder) {
222   unsigned sy = fieldFromInstruction(insn, 40, 7);
223   bool cy = fieldFromInstruction(insn, 47, 1);
224   unsigned sz = fieldFromInstruction(insn, 32, 7);
225   bool cz = fieldFromInstruction(insn, 39, 1);
226   uint64_t simm32 = SignExtend64<32>(fieldFromInstruction(insn, 0, 32));
227   DecodeStatus status;
228 
229   // Decode sz.
230   if (cz) {
231     status = DecodeI64RegisterClass(MI, sz, Address, Decoder);
232     if (status != MCDisassembler::Success)
233       return status;
234   } else {
235     MI.addOperand(MCOperand::createImm(0));
236   }
237 
238   // Decode sy.
239   if (cy) {
240     status = DecodeI64RegisterClass(MI, sy, Address, Decoder);
241     if (status != MCDisassembler::Success)
242       return status;
243   } else {
244     MI.addOperand(MCOperand::createImm(SignExtend32<7>(sy)));
245   }
246 
247   // Decode simm32.
248   MI.addOperand(MCOperand::createImm(simm32));
249 
250   return MCDisassembler::Success;
251 }
252 
253 static DecodeStatus DecodeAS(MCInst &MI, uint64_t insn, uint64_t Address,
254                              const void *Decoder) {
255   unsigned sz = fieldFromInstruction(insn, 32, 7);
256   bool cz = fieldFromInstruction(insn, 39, 1);
257   uint64_t simm32 = SignExtend64<32>(fieldFromInstruction(insn, 0, 32));
258   DecodeStatus status;
259 
260   // Decode sz.
261   if (cz) {
262     status = DecodeI64RegisterClass(MI, sz, Address, Decoder);
263     if (status != MCDisassembler::Success)
264       return status;
265   } else {
266     MI.addOperand(MCOperand::createImm(0));
267   }
268 
269   // Decode simm32.
270   MI.addOperand(MCOperand::createImm(simm32));
271 
272   return MCDisassembler::Success;
273 }
274 
275 static DecodeStatus DecodeMem(MCInst &MI, uint64_t insn, uint64_t Address,
276                               const void *Decoder, bool isLoad,
277                               DecodeFunc DecodeSX) {
278   unsigned sx = fieldFromInstruction(insn, 48, 7);
279 
280   DecodeStatus status;
281   if (isLoad) {
282     status = DecodeSX(MI, sx, Address, Decoder);
283     if (status != MCDisassembler::Success)
284       return status;
285   }
286 
287   status = DecodeASX(MI, insn, Address, Decoder);
288   if (status != MCDisassembler::Success)
289     return status;
290 
291   if (!isLoad) {
292     status = DecodeSX(MI, sx, Address, Decoder);
293     if (status != MCDisassembler::Success)
294       return status;
295   }
296   return MCDisassembler::Success;
297 }
298 
299 static DecodeStatus DecodeLoadI32(MCInst &Inst, uint64_t insn, uint64_t Address,
300                                   const void *Decoder) {
301   return DecodeMem(Inst, insn, Address, Decoder, true, DecodeI32RegisterClass);
302 }
303 
304 static DecodeStatus DecodeStoreI32(MCInst &Inst, uint64_t insn,
305                                    uint64_t Address, const void *Decoder) {
306   return DecodeMem(Inst, insn, Address, Decoder, false, DecodeI32RegisterClass);
307 }
308 
309 static DecodeStatus DecodeLoadI64(MCInst &Inst, uint64_t insn, uint64_t Address,
310                                   const void *Decoder) {
311   return DecodeMem(Inst, insn, Address, Decoder, true, DecodeI64RegisterClass);
312 }
313 
314 static DecodeStatus DecodeStoreI64(MCInst &Inst, uint64_t insn,
315                                    uint64_t Address, const void *Decoder) {
316   return DecodeMem(Inst, insn, Address, Decoder, false, DecodeI64RegisterClass);
317 }
318 
319 static DecodeStatus DecodeLoadF32(MCInst &Inst, uint64_t insn, uint64_t Address,
320                                   const void *Decoder) {
321   return DecodeMem(Inst, insn, Address, Decoder, true, DecodeF32RegisterClass);
322 }
323 
324 static DecodeStatus DecodeStoreF32(MCInst &Inst, uint64_t insn,
325                                    uint64_t Address, const void *Decoder) {
326   return DecodeMem(Inst, insn, Address, Decoder, false, DecodeF32RegisterClass);
327 }
328 
329 static DecodeStatus DecodeCall(MCInst &Inst, uint64_t insn, uint64_t Address,
330                                const void *Decoder) {
331   return DecodeMem(Inst, insn, Address, Decoder, true, DecodeI64RegisterClass);
332 }
333 
334 static DecodeStatus DecodeSIMM7(MCInst &MI, uint64_t insn, uint64_t Address,
335                                 const void *Decoder) {
336   uint64_t tgt = SignExtend64<7>(insn);
337   MI.addOperand(MCOperand::createImm(tgt));
338   return MCDisassembler::Success;
339 }
340 
341 static bool isIntegerBCKind(MCInst &MI) {
342 
343 #define BCm_kind(NAME)                                                         \
344   case NAME##rri:                                                              \
345   case NAME##rzi:                                                              \
346   case NAME##iri:                                                              \
347   case NAME##izi:                                                              \
348   case NAME##rri_nt:                                                           \
349   case NAME##rzi_nt:                                                           \
350   case NAME##iri_nt:                                                           \
351   case NAME##izi_nt:                                                           \
352   case NAME##rri_t:                                                            \
353   case NAME##rzi_t:                                                            \
354   case NAME##iri_t:                                                            \
355   case NAME##izi_t:
356 
357 #define BCRm_kind(NAME)                                                        \
358   case NAME##rr:                                                               \
359   case NAME##ir:                                                               \
360   case NAME##rr_nt:                                                            \
361   case NAME##ir_nt:                                                            \
362   case NAME##rr_t:                                                             \
363   case NAME##ir_t:
364 
365   {
366     using namespace llvm::VE;
367     switch (MI.getOpcode()) {
368       BCm_kind(BCFL) BCm_kind(BCFW) BCRm_kind(BRCFL)
369           BCRm_kind(BRCFW) return true;
370     }
371   }
372 #undef BCm_kind
373 
374   return false;
375 }
376 
377 // Decode CC Operand field.
378 static DecodeStatus DecodeCCOperand(MCInst &MI, uint64_t cf, uint64_t Address,
379                                     const void *Decoder) {
380   MI.addOperand(MCOperand::createImm(VEValToCondCode(cf, isIntegerBCKind(MI))));
381   return MCDisassembler::Success;
382 }
383 
384 // Decode branch condition instruction and CCOperand field in it.
385 static DecodeStatus DecodeBranchCondition(MCInst &MI, uint64_t insn,
386                                           uint64_t Address,
387                                           const void *Decoder) {
388   unsigned cf = fieldFromInstruction(insn, 48, 4);
389   bool cy = fieldFromInstruction(insn, 47, 1);
390   unsigned sy = fieldFromInstruction(insn, 40, 7);
391 
392   // Decode cf.
393   MI.addOperand(MCOperand::createImm(VEValToCondCode(cf, isIntegerBCKind(MI))));
394 
395   // Decode sy.
396   DecodeStatus status;
397   if (cy) {
398     status = DecodeI64RegisterClass(MI, sy, Address, Decoder);
399     if (status != MCDisassembler::Success)
400       return status;
401   } else {
402     MI.addOperand(MCOperand::createImm(SignExtend32<7>(sy)));
403   }
404 
405   // Decode MEMri.
406   return DecodeAS(MI, insn, Address, Decoder);
407 }
408 
409 static DecodeStatus DecodeBranchConditionAlways(MCInst &MI, uint64_t insn,
410                                                 uint64_t Address,
411                                                 const void *Decoder) {
412   // Decode MEMri.
413   return DecodeAS(MI, insn, Address, Decoder);
414 }
415