1//===------ PPCDisassembler.cpp - Disassembler for PowerPC ------*- 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#include "MCTargetDesc/PPCMCTargetDesc.h"
10#include "TargetInfo/PowerPCTargetInfo.h"
11#include "llvm/MC/MCDecoderOps.h"
12#include "llvm/MC/MCDisassembler/MCDisassembler.h"
13#include "llvm/MC/MCInst.h"
14#include "llvm/MC/MCSubtargetInfo.h"
15#include "llvm/MC/TargetRegistry.h"
16#include "llvm/Support/Endian.h"
17
18using namespace llvm;
19
20DEFINE_PPC_REGCLASSES
21
22#define DEBUG_TYPE "ppc-disassembler"
23
24typedef MCDisassembler::DecodeStatus DecodeStatus;
25
26namespace {
27class PPCDisassembler : public MCDisassembler {
28 bool IsLittleEndian;
29
30public:
31 PPCDisassembler(const MCSubtargetInfo &STI, MCContext &Ctx,
32 bool IsLittleEndian)
33 : MCDisassembler(STI, Ctx), IsLittleEndian(IsLittleEndian) {}
34
35 DecodeStatus getInstruction(MCInst &Instr, uint64_t &Size,
36 ArrayRef<uint8_t> Bytes, uint64_t Address,
37 raw_ostream &CStream) const override;
38};
39} // end anonymous namespace
40
41static MCDisassembler *createPPCDisassembler(const Target &T,
42 const MCSubtargetInfo &STI,
43 MCContext &Ctx) {
44 return new PPCDisassembler(STI, Ctx, /*IsLittleEndian=*/false);
45}
46
47static MCDisassembler *createPPCLEDisassembler(const Target &T,
48 const MCSubtargetInfo &STI,
49 MCContext &Ctx) {
50 return new PPCDisassembler(STI, Ctx, /*IsLittleEndian=*/true);
51}
52
53extern "C" LLVM_EXTERNAL_VISIBILITY void LLVMInitializePowerPCDisassembler() {
54 // Register the disassembler for each target.
55 TargetRegistry::RegisterMCDisassembler(T&: getThePPC32Target(),
56 Fn: createPPCDisassembler);
57 TargetRegistry::RegisterMCDisassembler(T&: getThePPC32LETarget(),
58 Fn: createPPCLEDisassembler);
59 TargetRegistry::RegisterMCDisassembler(T&: getThePPC64Target(),
60 Fn: createPPCDisassembler);
61 TargetRegistry::RegisterMCDisassembler(T&: getThePPC64LETarget(),
62 Fn: createPPCLEDisassembler);
63}
64
65static DecodeStatus decodeCondBrTarget(MCInst &Inst, unsigned Imm,
66 uint64_t /*Address*/,
67 const MCDisassembler * /*Decoder*/) {
68 Inst.addOperand(Op: MCOperand::createImm(Val: SignExtend32<14>(X: Imm)));
69 return MCDisassembler::Success;
70}
71
72static DecodeStatus decodeDirectBrTarget(MCInst &Inst, unsigned Imm,
73 uint64_t /*Address*/,
74 const MCDisassembler * /*Decoder*/) {
75 int32_t Offset = SignExtend32<24>(X: Imm);
76 Inst.addOperand(Op: MCOperand::createImm(Val: Offset));
77 return MCDisassembler::Success;
78}
79
80// FIXME: These can be generated by TableGen from the existing register
81// encoding values!
82
83template <std::size_t N>
84static DecodeStatus decodeRegisterClass(MCInst &Inst, uint64_t RegNo,
85 const MCPhysReg (&Regs)[N]) {
86 if (RegNo >= N)
87 return MCDisassembler::Fail;
88 Inst.addOperand(Op: MCOperand::createReg(Reg: Regs[RegNo]));
89 return MCDisassembler::Success;
90}
91
92static DecodeStatus DecodeCRRCRegisterClass(MCInst &Inst, uint64_t RegNo,
93 uint64_t Address,
94 const MCDisassembler *Decoder) {
95 return decodeRegisterClass(Inst, RegNo, Regs: CRRegs);
96}
97
98static DecodeStatus DecodeCRBITRCRegisterClass(MCInst &Inst, uint64_t RegNo,
99 uint64_t Address,
100 const MCDisassembler *Decoder) {
101 return decodeRegisterClass(Inst, RegNo, Regs: CRBITRegs);
102}
103
104static DecodeStatus DecodeF4RCRegisterClass(MCInst &Inst, uint64_t RegNo,
105 uint64_t Address,
106 const MCDisassembler *Decoder) {
107 return decodeRegisterClass(Inst, RegNo, Regs: FRegs);
108}
109
110static DecodeStatus DecodeF8RCRegisterClass(MCInst &Inst, uint64_t RegNo,
111 uint64_t Address,
112 const MCDisassembler *Decoder) {
113 return decodeRegisterClass(Inst, RegNo, Regs: FRegs);
114}
115
116static DecodeStatus DecodeFpRCRegisterClass(MCInst &Inst, uint64_t RegNo,
117 uint64_t Address,
118 const MCDisassembler *Decoder) {
119 if (RegNo > 30 || (RegNo & 1))
120 return MCDisassembler::Fail;
121 return decodeRegisterClass(Inst, RegNo: RegNo >> 1, Regs: FpRegs);
122}
123
124static DecodeStatus DecodeVFRCRegisterClass(MCInst &Inst, uint64_t RegNo,
125 uint64_t Address,
126 const MCDisassembler *Decoder) {
127 return decodeRegisterClass(Inst, RegNo, Regs: VFRegs);
128}
129
130static DecodeStatus DecodeVRRCRegisterClass(MCInst &Inst, uint64_t RegNo,
131 uint64_t Address,
132 const MCDisassembler *Decoder) {
133 return decodeRegisterClass(Inst, RegNo, Regs: VRegs);
134}
135
136static DecodeStatus DecodeVSRCRegisterClass(MCInst &Inst, uint64_t RegNo,
137 uint64_t Address,
138 const MCDisassembler *Decoder) {
139 return decodeRegisterClass(Inst, RegNo, Regs: VSRegs);
140}
141
142static DecodeStatus DecodeVSFRCRegisterClass(MCInst &Inst, uint64_t RegNo,
143 uint64_t Address,
144 const MCDisassembler *Decoder) {
145 return decodeRegisterClass(Inst, RegNo, Regs: VSFRegs);
146}
147
148static DecodeStatus DecodeVSSRCRegisterClass(MCInst &Inst, uint64_t RegNo,
149 uint64_t Address,
150 const MCDisassembler *Decoder) {
151 return decodeRegisterClass(Inst, RegNo, Regs: VSSRegs);
152}
153
154static DecodeStatus DecodeGPRCRegisterClass(MCInst &Inst, uint64_t RegNo,
155 uint64_t Address,
156 const MCDisassembler *Decoder) {
157 return decodeRegisterClass(Inst, RegNo, Regs: RRegs);
158}
159
160static DecodeStatus
161DecodeGPRC_NOR0RegisterClass(MCInst &Inst, uint64_t RegNo, uint64_t Address,
162 const MCDisassembler *Decoder) {
163 return decodeRegisterClass(Inst, RegNo, Regs: RRegsNoR0);
164}
165
166static DecodeStatus DecodeG8RCRegisterClass(MCInst &Inst, uint64_t RegNo,
167 uint64_t Address,
168 const MCDisassembler *Decoder) {
169 return decodeRegisterClass(Inst, RegNo, Regs: XRegs);
170}
171
172static DecodeStatus DecodeG8pRCRegisterClass(MCInst &Inst, uint64_t RegNo,
173 uint64_t Address,
174 const MCDisassembler *Decoder) {
175 return decodeRegisterClass(Inst, RegNo, Regs: XRegs);
176}
177
178static DecodeStatus
179DecodeG8RC_NOX0RegisterClass(MCInst &Inst, uint64_t RegNo, uint64_t Address,
180 const MCDisassembler *Decoder) {
181 return decodeRegisterClass(Inst, RegNo, Regs: XRegsNoX0);
182}
183
184#define DecodePointerLikeRegClass0 DecodeGPRCRegisterClass
185#define DecodePointerLikeRegClass1 DecodeGPRC_NOR0RegisterClass
186
187static DecodeStatus DecodeSPERCRegisterClass(MCInst &Inst, uint64_t RegNo,
188 uint64_t Address,
189 const MCDisassembler *Decoder) {
190 return decodeRegisterClass(Inst, RegNo, Regs: SPERegs);
191}
192
193static DecodeStatus DecodeACCRCRegisterClass(MCInst &Inst, uint64_t RegNo,
194 uint64_t Address,
195 const MCDisassembler *Decoder) {
196 return decodeRegisterClass(Inst, RegNo, Regs: ACCRegs);
197}
198
199static DecodeStatus DecodeWACCRCRegisterClass(MCInst &Inst, uint64_t RegNo,
200 uint64_t Address,
201 const void *Decoder) {
202 return decodeRegisterClass(Inst, RegNo, Regs: WACCRegs);
203}
204
205static DecodeStatus DecodeWACC_HIRCRegisterClass(MCInst &Inst, uint64_t RegNo,
206 uint64_t Address,
207 const void *Decoder) {
208 return decodeRegisterClass(Inst, RegNo, Regs: WACC_HIRegs);
209}
210
211// TODO: Make this function static when the register class is used by a new
212// instruction.
213DecodeStatus DecodeDMRROWRCRegisterClass(MCInst &Inst, uint64_t RegNo,
214 uint64_t Address,
215 const void *Decoder) {
216 return decodeRegisterClass(Inst, RegNo, Regs: DMRROWRegs);
217}
218
219static DecodeStatus DecodeDMRROWpRCRegisterClass(MCInst &Inst, uint64_t RegNo,
220 uint64_t Address,
221 const void *Decoder) {
222 return decodeRegisterClass(Inst, RegNo, Regs: DMRROWpRegs);
223}
224
225static DecodeStatus DecodeDMRRCRegisterClass(MCInst &Inst, uint64_t RegNo,
226 uint64_t Address,
227 const void *Decoder) {
228 return decodeRegisterClass(Inst, RegNo, Regs: DMRRegs);
229}
230
231// TODO: Make this function static when the register class is used by a new
232// instruction.
233DecodeStatus DecodeDMRpRCRegisterClass(MCInst &Inst, uint64_t RegNo,
234 uint64_t Address, const void *Decoder) {
235 return decodeRegisterClass(Inst, RegNo, Regs: DMRpRegs);
236}
237
238static DecodeStatus DecodeVSRpRCRegisterClass(MCInst &Inst, uint64_t RegNo,
239 uint64_t Address,
240 const MCDisassembler *Decoder) {
241 return decodeRegisterClass(Inst, RegNo, Regs: VSRpRegs);
242}
243
244#define DecodeQSRCRegisterClass DecodeQFRCRegisterClass
245#define DecodeQBRCRegisterClass DecodeQFRCRegisterClass
246
247template <unsigned N>
248static DecodeStatus decodeUImmOperand(MCInst &Inst, uint64_t Imm,
249 int64_t Address,
250 const MCDisassembler *Decoder) {
251 if (!isUInt<N>(Imm))
252 return MCDisassembler::Fail;
253 Inst.addOperand(Op: MCOperand::createImm(Val: Imm));
254 return MCDisassembler::Success;
255}
256
257template <unsigned N>
258static DecodeStatus decodeSImmOperand(MCInst &Inst, uint64_t Imm,
259 int64_t Address,
260 const MCDisassembler *Decoder) {
261 if (!isUInt<N>(Imm))
262 return MCDisassembler::Fail;
263 Inst.addOperand(Op: MCOperand::createImm(Val: SignExtend64<N>(Imm)));
264 return MCDisassembler::Success;
265}
266
267static DecodeStatus decodeImmZeroOperand(MCInst &Inst, uint64_t Imm,
268 int64_t Address,
269 const MCDisassembler *Decoder) {
270 if (Imm != 0)
271 return MCDisassembler::Fail;
272 Inst.addOperand(Op: MCOperand::createImm(Val: Imm));
273 return MCDisassembler::Success;
274}
275
276static DecodeStatus decodeVSRpEvenOperands(MCInst &Inst, uint64_t RegNo,
277 uint64_t Address,
278 const MCDisassembler *Decoder) {
279 if (RegNo & 1)
280 return MCDisassembler::Fail;
281 Inst.addOperand(Op: MCOperand::createReg(Reg: VSRpRegs[RegNo >> 1]));
282 return MCDisassembler::Success;
283}
284
285static DecodeStatus decodeDispRIXOperand(MCInst &Inst, uint64_t Imm,
286 int64_t Address,
287 const MCDisassembler *Decoder) {
288 // The rix displacement is an immediate shifted by 2
289 Inst.addOperand(Op: MCOperand::createImm(Val: SignExtend64<16>(x: Imm << 2)));
290 return MCDisassembler::Success;
291}
292
293static DecodeStatus decodeDispRIHashOperand(MCInst &Inst, uint64_t Imm,
294 int64_t Address,
295 const MCDisassembler *Decoder) {
296 // Decode the disp field for a hash store or hash check operation.
297 // The field is composed of an immediate value that is 6 bits
298 // and covers the range -8 to -512. The immediate is always negative and 2s
299 // complement which is why we sign extend a 7 bit value.
300 const int64_t Disp = SignExtend64<7>(x: (Imm & 0x3F) + 64) * 8;
301
302 Inst.addOperand(Op: MCOperand::createImm(Val: Disp));
303 return MCDisassembler::Success;
304}
305
306static DecodeStatus decodeDispRIX16Operand(MCInst &Inst, uint64_t Imm,
307 int64_t Address,
308 const MCDisassembler *Decoder) {
309 // The rix16 displacement has 12-bits which are shifted by 4.
310 Inst.addOperand(Op: MCOperand::createImm(Val: SignExtend64<16>(x: Imm << 4)));
311 return MCDisassembler::Success;
312}
313
314static DecodeStatus decodeDispSPE8Operand(MCInst &Inst, uint64_t Imm,
315 int64_t Address,
316 const MCDisassembler *Decoder) {
317 // Decode the dispSPE8 field, which has 5-bits, 8-byte aligned.
318
319 uint64_t Disp = Imm & 0x1F;
320
321 Inst.addOperand(Op: MCOperand::createImm(Val: Disp << 3));
322 return MCDisassembler::Success;
323}
324
325static DecodeStatus decodeDispSPE4Operand(MCInst &Inst, uint64_t Imm,
326 int64_t Address,
327 const MCDisassembler *Decoder) {
328 // Decode the dispSPE8 field, which has 5-bits, 4-byte aligned.
329
330 uint64_t Disp = Imm & 0x1F;
331
332 Inst.addOperand(Op: MCOperand::createImm(Val: Disp << 2));
333 return MCDisassembler::Success;
334}
335
336static DecodeStatus decodeDispSPE2Operand(MCInst &Inst, uint64_t Imm,
337 int64_t Address,
338 const MCDisassembler *Decoder) {
339 // Decode the dispSPE8 field, which has 5-bits, 2-byte aligned.
340
341 uint64_t Disp = Imm & 0x1F;
342 Inst.addOperand(Op: MCOperand::createImm(Val: Disp << 1));
343 return MCDisassembler::Success;
344}
345
346static DecodeStatus decodeCRBitMOperand(MCInst &Inst, uint64_t Imm,
347 int64_t Address,
348 const MCDisassembler *Decoder) {
349 // The cr bit encoding is 0x80 >> cr_reg_num.
350
351 unsigned Zeros = llvm::countr_zero(Val: Imm);
352 if (Zeros >= 8)
353 return MCDisassembler::Fail;
354
355 Inst.addOperand(Op: MCOperand::createReg(Reg: CRRegs[7 - Zeros]));
356 return MCDisassembler::Success;
357}
358
359#include "PPCGenDisassemblerTables.inc"
360
361DecodeStatus PPCDisassembler::getInstruction(MCInst &MI, uint64_t &Size,
362 ArrayRef<uint8_t> Bytes,
363 uint64_t Address,
364 raw_ostream &CS) const {
365 auto *ReadFunc = IsLittleEndian ? support::endian::read32le
366 : support::endian::read32be;
367
368 // If this is an 8-byte prefixed instruction, handle it here.
369 // Note: prefixed instructions aren't technically 8-byte entities - the prefix
370 // appears in memory at an address 4 bytes prior to that of the base
371 // instruction regardless of endianness. So we read the two pieces and
372 // rebuild the 8-byte instruction.
373 // TODO: In this function we call decodeInstruction several times with
374 // different decoder tables. It may be possible to only call once by
375 // looking at the top 6 bits of the instruction.
376 if (STI.hasFeature(Feature: PPC::FeaturePrefixInstrs) && Bytes.size() >= 8) {
377 uint32_t Prefix = ReadFunc(Bytes.data());
378 uint32_t BaseInst = ReadFunc(Bytes.data() + 4);
379 uint64_t Inst = BaseInst | (uint64_t)Prefix << 32;
380 DecodeStatus result = decodeInstruction(DecodeTable: DecoderTable64, MI, insn: Inst, Address,
381 DisAsm: this, STI);
382 if (result != MCDisassembler::Fail) {
383 Size = 8;
384 return result;
385 }
386 }
387
388 // Get the four bytes of the instruction.
389 Size = 4;
390 if (Bytes.size() < 4) {
391 Size = 0;
392 return MCDisassembler::Fail;
393 }
394
395 // Read the instruction in the proper endianness.
396 uint64_t Inst = ReadFunc(Bytes.data());
397
398 if (STI.hasFeature(Feature: PPC::FeatureSPE)) {
399 DecodeStatus result =
400 decodeInstruction(DecodeTable: DecoderTableSPE32, MI, insn: Inst, Address, DisAsm: this, STI);
401 if (result != MCDisassembler::Fail)
402 return result;
403 }
404
405 return decodeInstruction(DecodeTable: DecoderTable32, MI, insn: Inst, Address, DisAsm: this, STI);
406}
407