1 //===-- MipsAsmBackend.cpp - Mips Asm Backend ----------------------------===//
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 implements the MipsAsmBackend class.
10 //
11 //===----------------------------------------------------------------------===//
12 //
13
14 #include "MCTargetDesc/MipsAsmBackend.h"
15 #include "MCTargetDesc/MipsABIInfo.h"
16 #include "MCTargetDesc/MipsFixupKinds.h"
17 #include "MCTargetDesc/MipsMCExpr.h"
18 #include "MCTargetDesc/MipsMCTargetDesc.h"
19 #include "llvm/ADT/STLExtras.h"
20 #include "llvm/MC/MCAsmBackend.h"
21 #include "llvm/MC/MCAssembler.h"
22 #include "llvm/MC/MCContext.h"
23 #include "llvm/MC/MCDirectives.h"
24 #include "llvm/MC/MCELFObjectWriter.h"
25 #include "llvm/MC/MCFixupKindInfo.h"
26 #include "llvm/MC/MCObjectWriter.h"
27 #include "llvm/MC/MCSubtargetInfo.h"
28 #include "llvm/MC/MCTargetOptions.h"
29 #include "llvm/MC/MCValue.h"
30 #include "llvm/Support/ErrorHandling.h"
31 #include "llvm/Support/Format.h"
32 #include "llvm/Support/MathExtras.h"
33 #include "llvm/Support/raw_ostream.h"
34
35 using namespace llvm;
36
37 // Prepare value for the target space for it
adjustFixupValue(const MCFixup & Fixup,uint64_t Value,MCContext & Ctx)38 static unsigned adjustFixupValue(const MCFixup &Fixup, uint64_t Value,
39 MCContext &Ctx) {
40
41 unsigned Kind = Fixup.getKind();
42
43 // Add/subtract and shift
44 switch (Kind) {
45 default:
46 return 0;
47 case FK_Data_2:
48 case Mips::fixup_Mips_LO16:
49 case Mips::fixup_Mips_GPREL16:
50 case Mips::fixup_Mips_GPOFF_HI:
51 case Mips::fixup_Mips_GPOFF_LO:
52 case Mips::fixup_Mips_GOT_PAGE:
53 case Mips::fixup_Mips_GOT_OFST:
54 case Mips::fixup_Mips_GOT_DISP:
55 case Mips::fixup_Mips_GOT_LO16:
56 case Mips::fixup_Mips_CALL_LO16:
57 case Mips::fixup_MICROMIPS_GPOFF_HI:
58 case Mips::fixup_MICROMIPS_GPOFF_LO:
59 case Mips::fixup_MICROMIPS_LO16:
60 case Mips::fixup_MICROMIPS_GOT_PAGE:
61 case Mips::fixup_MICROMIPS_GOT_OFST:
62 case Mips::fixup_MICROMIPS_GOT_DISP:
63 case Mips::fixup_MIPS_PCLO16:
64 Value &= 0xffff;
65 break;
66 case FK_DTPRel_4:
67 case FK_DTPRel_8:
68 case FK_TPRel_4:
69 case FK_TPRel_8:
70 case FK_GPRel_4:
71 case FK_Data_4:
72 case FK_Data_8:
73 case Mips::fixup_Mips_SUB:
74 case Mips::fixup_MICROMIPS_SUB:
75 break;
76 case Mips::fixup_Mips_PC16:
77 // The displacement is then divided by 4 to give us an 18 bit
78 // address range. Forcing a signed division because Value can be negative.
79 Value = (int64_t)Value / 4;
80 // We now check if Value can be encoded as a 16-bit signed immediate.
81 if (!isInt<16>(Value)) {
82 Ctx.reportError(Fixup.getLoc(), "out of range PC16 fixup");
83 return 0;
84 }
85 break;
86 case Mips::fixup_MIPS_PC19_S2:
87 case Mips::fixup_MICROMIPS_PC19_S2:
88 // Forcing a signed division because Value can be negative.
89 Value = (int64_t)Value / 4;
90 // We now check if Value can be encoded as a 19-bit signed immediate.
91 if (!isInt<19>(Value)) {
92 Ctx.reportError(Fixup.getLoc(), "out of range PC19 fixup");
93 return 0;
94 }
95 break;
96 case Mips::fixup_Mips_26:
97 // So far we are only using this type for jumps.
98 // The displacement is then divided by 4 to give us an 28 bit
99 // address range.
100 Value >>= 2;
101 break;
102 case Mips::fixup_Mips_HI16:
103 case Mips::fixup_Mips_GOT:
104 case Mips::fixup_MICROMIPS_GOT16:
105 case Mips::fixup_Mips_GOT_HI16:
106 case Mips::fixup_Mips_CALL_HI16:
107 case Mips::fixup_MICROMIPS_HI16:
108 case Mips::fixup_MIPS_PCHI16:
109 // Get the 2nd 16-bits. Also add 1 if bit 15 is 1.
110 Value = ((Value + 0x8000) >> 16) & 0xffff;
111 break;
112 case Mips::fixup_Mips_HIGHER:
113 case Mips::fixup_MICROMIPS_HIGHER:
114 // Get the 3rd 16-bits.
115 Value = ((Value + 0x80008000LL) >> 32) & 0xffff;
116 break;
117 case Mips::fixup_Mips_HIGHEST:
118 case Mips::fixup_MICROMIPS_HIGHEST:
119 // Get the 4th 16-bits.
120 Value = ((Value + 0x800080008000LL) >> 48) & 0xffff;
121 break;
122 case Mips::fixup_MICROMIPS_26_S1:
123 Value >>= 1;
124 break;
125 case Mips::fixup_MICROMIPS_PC7_S1:
126 Value -= 4;
127 // Forcing a signed division because Value can be negative.
128 Value = (int64_t) Value / 2;
129 // We now check if Value can be encoded as a 7-bit signed immediate.
130 if (!isInt<7>(Value)) {
131 Ctx.reportError(Fixup.getLoc(), "out of range PC7 fixup");
132 return 0;
133 }
134 break;
135 case Mips::fixup_MICROMIPS_PC10_S1:
136 Value -= 2;
137 // Forcing a signed division because Value can be negative.
138 Value = (int64_t) Value / 2;
139 // We now check if Value can be encoded as a 10-bit signed immediate.
140 if (!isInt<10>(Value)) {
141 Ctx.reportError(Fixup.getLoc(), "out of range PC10 fixup");
142 return 0;
143 }
144 break;
145 case Mips::fixup_MICROMIPS_PC16_S1:
146 Value -= 4;
147 // Forcing a signed division because Value can be negative.
148 Value = (int64_t)Value / 2;
149 // We now check if Value can be encoded as a 16-bit signed immediate.
150 if (!isInt<16>(Value)) {
151 Ctx.reportError(Fixup.getLoc(), "out of range PC16 fixup");
152 return 0;
153 }
154 break;
155 case Mips::fixup_MIPS_PC18_S3:
156 // Forcing a signed division because Value can be negative.
157 Value = (int64_t)Value / 8;
158 // We now check if Value can be encoded as a 18-bit signed immediate.
159 if (!isInt<18>(Value)) {
160 Ctx.reportError(Fixup.getLoc(), "out of range PC18 fixup");
161 return 0;
162 }
163 break;
164 case Mips::fixup_MICROMIPS_PC18_S3:
165 // Check alignment.
166 if ((Value & 7)) {
167 Ctx.reportError(Fixup.getLoc(), "out of range PC18 fixup");
168 }
169 // Forcing a signed division because Value can be negative.
170 Value = (int64_t)Value / 8;
171 // We now check if Value can be encoded as a 18-bit signed immediate.
172 if (!isInt<18>(Value)) {
173 Ctx.reportError(Fixup.getLoc(), "out of range PC18 fixup");
174 return 0;
175 }
176 break;
177 case Mips::fixup_MIPS_PC21_S2:
178 // Forcing a signed division because Value can be negative.
179 Value = (int64_t) Value / 4;
180 // We now check if Value can be encoded as a 21-bit signed immediate.
181 if (!isInt<21>(Value)) {
182 Ctx.reportError(Fixup.getLoc(), "out of range PC21 fixup");
183 return 0;
184 }
185 break;
186 case Mips::fixup_MIPS_PC26_S2:
187 // Forcing a signed division because Value can be negative.
188 Value = (int64_t) Value / 4;
189 // We now check if Value can be encoded as a 26-bit signed immediate.
190 if (!isInt<26>(Value)) {
191 Ctx.reportError(Fixup.getLoc(), "out of range PC26 fixup");
192 return 0;
193 }
194 break;
195 case Mips::fixup_MICROMIPS_PC26_S1:
196 // Forcing a signed division because Value can be negative.
197 Value = (int64_t)Value / 2;
198 // We now check if Value can be encoded as a 26-bit signed immediate.
199 if (!isInt<26>(Value)) {
200 Ctx.reportError(Fixup.getLoc(), "out of range PC26 fixup");
201 return 0;
202 }
203 break;
204 case Mips::fixup_MICROMIPS_PC21_S1:
205 // Forcing a signed division because Value can be negative.
206 Value = (int64_t)Value / 2;
207 // We now check if Value can be encoded as a 21-bit signed immediate.
208 if (!isInt<21>(Value)) {
209 Ctx.reportError(Fixup.getLoc(), "out of range PC21 fixup");
210 return 0;
211 }
212 break;
213 }
214
215 return Value;
216 }
217
218 std::unique_ptr<MCObjectTargetWriter>
createObjectTargetWriter() const219 MipsAsmBackend::createObjectTargetWriter() const {
220 return createMipsELFObjectWriter(TheTriple, IsN32);
221 }
222
223 // Little-endian fixup data byte ordering:
224 // mips32r2: a | b | x | x
225 // microMIPS: x | x | a | b
226
needsMMLEByteOrder(unsigned Kind)227 static bool needsMMLEByteOrder(unsigned Kind) {
228 return Kind != Mips::fixup_MICROMIPS_PC10_S1 &&
229 Kind >= Mips::fixup_MICROMIPS_26_S1 &&
230 Kind < Mips::LastTargetFixupKind;
231 }
232
233 // Calculate index for microMIPS specific little endian byte order
calculateMMLEIndex(unsigned i)234 static unsigned calculateMMLEIndex(unsigned i) {
235 assert(i <= 3 && "Index out of range!");
236
237 return (1 - i / 2) * 2 + i % 2;
238 }
239
240 /// ApplyFixup - Apply the \p Value for given \p Fixup into the provided
241 /// data fragment, at the offset specified by the fixup and following the
242 /// fixup kind as appropriate.
applyFixup(const MCAssembler & Asm,const MCFixup & Fixup,const MCValue & Target,MutableArrayRef<char> Data,uint64_t Value,bool IsResolved,const MCSubtargetInfo * STI) const243 void MipsAsmBackend::applyFixup(const MCAssembler &Asm, const MCFixup &Fixup,
244 const MCValue &Target,
245 MutableArrayRef<char> Data, uint64_t Value,
246 bool IsResolved,
247 const MCSubtargetInfo *STI) const {
248 MCFixupKind Kind = Fixup.getKind();
249 MCContext &Ctx = Asm.getContext();
250 Value = adjustFixupValue(Fixup, Value, Ctx);
251
252 if (!Value)
253 return; // Doesn't change encoding.
254
255 // Where do we start in the object
256 unsigned Offset = Fixup.getOffset();
257 // Number of bytes we need to fixup
258 unsigned NumBytes = (getFixupKindInfo(Kind).TargetSize + 7) / 8;
259 // Used to point to big endian bytes
260 unsigned FullSize;
261
262 switch ((unsigned)Kind) {
263 case FK_Data_2:
264 case Mips::fixup_Mips_16:
265 case Mips::fixup_MICROMIPS_PC10_S1:
266 FullSize = 2;
267 break;
268 case FK_Data_8:
269 case Mips::fixup_Mips_64:
270 FullSize = 8;
271 break;
272 case FK_Data_4:
273 default:
274 FullSize = 4;
275 break;
276 }
277
278 // Grab current value, if any, from bits.
279 uint64_t CurVal = 0;
280
281 bool microMipsLEByteOrder = needsMMLEByteOrder((unsigned) Kind);
282
283 for (unsigned i = 0; i != NumBytes; ++i) {
284 unsigned Idx = Endian == llvm::endianness::little
285 ? (microMipsLEByteOrder ? calculateMMLEIndex(i) : i)
286 : (FullSize - 1 - i);
287 CurVal |= (uint64_t)((uint8_t)Data[Offset + Idx]) << (i*8);
288 }
289
290 uint64_t Mask = ((uint64_t)(-1) >>
291 (64 - getFixupKindInfo(Kind).TargetSize));
292 CurVal |= Value & Mask;
293
294 // Write out the fixed up bytes back to the code/data bits.
295 for (unsigned i = 0; i != NumBytes; ++i) {
296 unsigned Idx = Endian == llvm::endianness::little
297 ? (microMipsLEByteOrder ? calculateMMLEIndex(i) : i)
298 : (FullSize - 1 - i);
299 Data[Offset + Idx] = (uint8_t)((CurVal >> (i*8)) & 0xff);
300 }
301 }
302
getFixupKind(StringRef Name) const303 std::optional<MCFixupKind> MipsAsmBackend::getFixupKind(StringRef Name) const {
304 unsigned Type = llvm::StringSwitch<unsigned>(Name)
305 .Case("BFD_RELOC_NONE", ELF::R_MIPS_NONE)
306 .Case("BFD_RELOC_16", ELF::R_MIPS_16)
307 .Case("BFD_RELOC_32", ELF::R_MIPS_32)
308 .Case("BFD_RELOC_64", ELF::R_MIPS_64)
309 .Default(-1u);
310 if (Type != -1u)
311 return static_cast<MCFixupKind>(FirstLiteralRelocationKind + Type);
312
313 return StringSwitch<std::optional<MCFixupKind>>(Name)
314 .Case("R_MIPS_NONE", FK_NONE)
315 .Case("R_MIPS_32", FK_Data_4)
316 .Case("R_MIPS_CALL_HI16", (MCFixupKind)Mips::fixup_Mips_CALL_HI16)
317 .Case("R_MIPS_CALL_LO16", (MCFixupKind)Mips::fixup_Mips_CALL_LO16)
318 .Case("R_MIPS_CALL16", (MCFixupKind)Mips::fixup_Mips_CALL16)
319 .Case("R_MIPS_GOT16", (MCFixupKind)Mips::fixup_Mips_GOT)
320 .Case("R_MIPS_GOT_PAGE", (MCFixupKind)Mips::fixup_Mips_GOT_PAGE)
321 .Case("R_MIPS_GOT_OFST", (MCFixupKind)Mips::fixup_Mips_GOT_OFST)
322 .Case("R_MIPS_GOT_DISP", (MCFixupKind)Mips::fixup_Mips_GOT_DISP)
323 .Case("R_MIPS_GOT_HI16", (MCFixupKind)Mips::fixup_Mips_GOT_HI16)
324 .Case("R_MIPS_GOT_LO16", (MCFixupKind)Mips::fixup_Mips_GOT_LO16)
325 .Case("R_MIPS_TLS_GOTTPREL", (MCFixupKind)Mips::fixup_Mips_GOTTPREL)
326 .Case("R_MIPS_TLS_DTPREL_HI16", (MCFixupKind)Mips::fixup_Mips_DTPREL_HI)
327 .Case("R_MIPS_TLS_DTPREL_LO16", (MCFixupKind)Mips::fixup_Mips_DTPREL_LO)
328 .Case("R_MIPS_TLS_GD", (MCFixupKind)Mips::fixup_Mips_TLSGD)
329 .Case("R_MIPS_TLS_LDM", (MCFixupKind)Mips::fixup_Mips_TLSLDM)
330 .Case("R_MIPS_TLS_TPREL_HI16", (MCFixupKind)Mips::fixup_Mips_TPREL_HI)
331 .Case("R_MIPS_TLS_TPREL_LO16", (MCFixupKind)Mips::fixup_Mips_TPREL_LO)
332 .Case("R_MICROMIPS_CALL16", (MCFixupKind)Mips::fixup_MICROMIPS_CALL16)
333 .Case("R_MICROMIPS_GOT_DISP", (MCFixupKind)Mips::fixup_MICROMIPS_GOT_DISP)
334 .Case("R_MICROMIPS_GOT_PAGE", (MCFixupKind)Mips::fixup_MICROMIPS_GOT_PAGE)
335 .Case("R_MICROMIPS_GOT_OFST", (MCFixupKind)Mips::fixup_MICROMIPS_GOT_OFST)
336 .Case("R_MICROMIPS_GOT16", (MCFixupKind)Mips::fixup_MICROMIPS_GOT16)
337 .Case("R_MICROMIPS_TLS_GOTTPREL",
338 (MCFixupKind)Mips::fixup_MICROMIPS_GOTTPREL)
339 .Case("R_MICROMIPS_TLS_DTPREL_HI16",
340 (MCFixupKind)Mips::fixup_MICROMIPS_TLS_DTPREL_HI16)
341 .Case("R_MICROMIPS_TLS_DTPREL_LO16",
342 (MCFixupKind)Mips::fixup_MICROMIPS_TLS_DTPREL_LO16)
343 .Case("R_MICROMIPS_TLS_GD", (MCFixupKind)Mips::fixup_MICROMIPS_TLS_GD)
344 .Case("R_MICROMIPS_TLS_LDM", (MCFixupKind)Mips::fixup_MICROMIPS_TLS_LDM)
345 .Case("R_MICROMIPS_TLS_TPREL_HI16",
346 (MCFixupKind)Mips::fixup_MICROMIPS_TLS_TPREL_HI16)
347 .Case("R_MICROMIPS_TLS_TPREL_LO16",
348 (MCFixupKind)Mips::fixup_MICROMIPS_TLS_TPREL_LO16)
349 .Case("R_MIPS_JALR", (MCFixupKind)Mips::fixup_Mips_JALR)
350 .Case("R_MICROMIPS_JALR", (MCFixupKind)Mips::fixup_MICROMIPS_JALR)
351 .Default(MCAsmBackend::getFixupKind(Name));
352 }
353
354 const MCFixupKindInfo &MipsAsmBackend::
getFixupKindInfo(MCFixupKind Kind) const355 getFixupKindInfo(MCFixupKind Kind) const {
356 const static MCFixupKindInfo LittleEndianInfos[] = {
357 // This table *must* be in same the order of fixup_* kinds in
358 // MipsFixupKinds.h.
359 //
360 // name offset bits flags
361 { "fixup_Mips_16", 0, 16, 0 },
362 { "fixup_Mips_32", 0, 32, 0 },
363 { "fixup_Mips_REL32", 0, 32, 0 },
364 { "fixup_Mips_26", 0, 26, 0 },
365 { "fixup_Mips_HI16", 0, 16, 0 },
366 { "fixup_Mips_LO16", 0, 16, 0 },
367 { "fixup_Mips_GPREL16", 0, 16, 0 },
368 { "fixup_Mips_LITERAL", 0, 16, 0 },
369 { "fixup_Mips_GOT", 0, 16, 0 },
370 { "fixup_Mips_PC16", 0, 16, MCFixupKindInfo::FKF_IsPCRel },
371 { "fixup_Mips_CALL16", 0, 16, 0 },
372 { "fixup_Mips_GPREL32", 0, 32, 0 },
373 { "fixup_Mips_SHIFT5", 6, 5, 0 },
374 { "fixup_Mips_SHIFT6", 6, 5, 0 },
375 { "fixup_Mips_64", 0, 64, 0 },
376 { "fixup_Mips_TLSGD", 0, 16, 0 },
377 { "fixup_Mips_GOTTPREL", 0, 16, 0 },
378 { "fixup_Mips_TPREL_HI", 0, 16, 0 },
379 { "fixup_Mips_TPREL_LO", 0, 16, 0 },
380 { "fixup_Mips_TLSLDM", 0, 16, 0 },
381 { "fixup_Mips_DTPREL_HI", 0, 16, 0 },
382 { "fixup_Mips_DTPREL_LO", 0, 16, 0 },
383 { "fixup_Mips_Branch_PCRel", 0, 16, MCFixupKindInfo::FKF_IsPCRel },
384 { "fixup_Mips_GPOFF_HI", 0, 16, 0 },
385 { "fixup_MICROMIPS_GPOFF_HI",0, 16, 0 },
386 { "fixup_Mips_GPOFF_LO", 0, 16, 0 },
387 { "fixup_MICROMIPS_GPOFF_LO",0, 16, 0 },
388 { "fixup_Mips_GOT_PAGE", 0, 16, 0 },
389 { "fixup_Mips_GOT_OFST", 0, 16, 0 },
390 { "fixup_Mips_GOT_DISP", 0, 16, 0 },
391 { "fixup_Mips_HIGHER", 0, 16, 0 },
392 { "fixup_MICROMIPS_HIGHER", 0, 16, 0 },
393 { "fixup_Mips_HIGHEST", 0, 16, 0 },
394 { "fixup_MICROMIPS_HIGHEST", 0, 16, 0 },
395 { "fixup_Mips_GOT_HI16", 0, 16, 0 },
396 { "fixup_Mips_GOT_LO16", 0, 16, 0 },
397 { "fixup_Mips_CALL_HI16", 0, 16, 0 },
398 { "fixup_Mips_CALL_LO16", 0, 16, 0 },
399 { "fixup_Mips_PC18_S3", 0, 18, MCFixupKindInfo::FKF_IsPCRel },
400 { "fixup_MIPS_PC19_S2", 0, 19, MCFixupKindInfo::FKF_IsPCRel },
401 { "fixup_MIPS_PC21_S2", 0, 21, MCFixupKindInfo::FKF_IsPCRel },
402 { "fixup_MIPS_PC26_S2", 0, 26, MCFixupKindInfo::FKF_IsPCRel },
403 { "fixup_MIPS_PCHI16", 0, 16, MCFixupKindInfo::FKF_IsPCRel },
404 { "fixup_MIPS_PCLO16", 0, 16, MCFixupKindInfo::FKF_IsPCRel },
405 { "fixup_MICROMIPS_26_S1", 0, 26, 0 },
406 { "fixup_MICROMIPS_HI16", 0, 16, 0 },
407 { "fixup_MICROMIPS_LO16", 0, 16, 0 },
408 { "fixup_MICROMIPS_GOT16", 0, 16, 0 },
409 { "fixup_MICROMIPS_PC7_S1", 0, 7, MCFixupKindInfo::FKF_IsPCRel },
410 { "fixup_MICROMIPS_PC10_S1", 0, 10, MCFixupKindInfo::FKF_IsPCRel },
411 { "fixup_MICROMIPS_PC16_S1", 0, 16, MCFixupKindInfo::FKF_IsPCRel },
412 { "fixup_MICROMIPS_PC26_S1", 0, 26, MCFixupKindInfo::FKF_IsPCRel },
413 { "fixup_MICROMIPS_PC19_S2", 0, 19, MCFixupKindInfo::FKF_IsPCRel },
414 { "fixup_MICROMIPS_PC18_S3", 0, 18, MCFixupKindInfo::FKF_IsPCRel },
415 { "fixup_MICROMIPS_PC21_S1", 0, 21, MCFixupKindInfo::FKF_IsPCRel },
416 { "fixup_MICROMIPS_CALL16", 0, 16, 0 },
417 { "fixup_MICROMIPS_GOT_DISP", 0, 16, 0 },
418 { "fixup_MICROMIPS_GOT_PAGE", 0, 16, 0 },
419 { "fixup_MICROMIPS_GOT_OFST", 0, 16, 0 },
420 { "fixup_MICROMIPS_TLS_GD", 0, 16, 0 },
421 { "fixup_MICROMIPS_TLS_LDM", 0, 16, 0 },
422 { "fixup_MICROMIPS_TLS_DTPREL_HI16", 0, 16, 0 },
423 { "fixup_MICROMIPS_TLS_DTPREL_LO16", 0, 16, 0 },
424 { "fixup_MICROMIPS_GOTTPREL", 0, 16, 0 },
425 { "fixup_MICROMIPS_TLS_TPREL_HI16", 0, 16, 0 },
426 { "fixup_MICROMIPS_TLS_TPREL_LO16", 0, 16, 0 },
427 { "fixup_Mips_SUB", 0, 64, 0 },
428 { "fixup_MICROMIPS_SUB", 0, 64, 0 },
429 { "fixup_Mips_JALR", 0, 32, 0 },
430 { "fixup_MICROMIPS_JALR", 0, 32, 0 }
431 };
432 static_assert(std::size(LittleEndianInfos) == Mips::NumTargetFixupKinds,
433 "Not all MIPS little endian fixup kinds added!");
434
435 const static MCFixupKindInfo BigEndianInfos[] = {
436 // This table *must* be in same the order of fixup_* kinds in
437 // MipsFixupKinds.h.
438 //
439 // name offset bits flags
440 { "fixup_Mips_16", 16, 16, 0 },
441 { "fixup_Mips_32", 0, 32, 0 },
442 { "fixup_Mips_REL32", 0, 32, 0 },
443 { "fixup_Mips_26", 6, 26, 0 },
444 { "fixup_Mips_HI16", 16, 16, 0 },
445 { "fixup_Mips_LO16", 16, 16, 0 },
446 { "fixup_Mips_GPREL16", 16, 16, 0 },
447 { "fixup_Mips_LITERAL", 16, 16, 0 },
448 { "fixup_Mips_GOT", 16, 16, 0 },
449 { "fixup_Mips_PC16", 16, 16, MCFixupKindInfo::FKF_IsPCRel },
450 { "fixup_Mips_CALL16", 16, 16, 0 },
451 { "fixup_Mips_GPREL32", 0, 32, 0 },
452 { "fixup_Mips_SHIFT5", 21, 5, 0 },
453 { "fixup_Mips_SHIFT6", 21, 5, 0 },
454 { "fixup_Mips_64", 0, 64, 0 },
455 { "fixup_Mips_TLSGD", 16, 16, 0 },
456 { "fixup_Mips_GOTTPREL", 16, 16, 0 },
457 { "fixup_Mips_TPREL_HI", 16, 16, 0 },
458 { "fixup_Mips_TPREL_LO", 16, 16, 0 },
459 { "fixup_Mips_TLSLDM", 16, 16, 0 },
460 { "fixup_Mips_DTPREL_HI", 16, 16, 0 },
461 { "fixup_Mips_DTPREL_LO", 16, 16, 0 },
462 { "fixup_Mips_Branch_PCRel",16, 16, MCFixupKindInfo::FKF_IsPCRel },
463 { "fixup_Mips_GPOFF_HI", 16, 16, 0 },
464 { "fixup_MICROMIPS_GPOFF_HI", 16, 16, 0 },
465 { "fixup_Mips_GPOFF_LO", 16, 16, 0 },
466 { "fixup_MICROMIPS_GPOFF_LO", 16, 16, 0 },
467 { "fixup_Mips_GOT_PAGE", 16, 16, 0 },
468 { "fixup_Mips_GOT_OFST", 16, 16, 0 },
469 { "fixup_Mips_GOT_DISP", 16, 16, 0 },
470 { "fixup_Mips_HIGHER", 16, 16, 0 },
471 { "fixup_MICROMIPS_HIGHER", 16, 16, 0 },
472 { "fixup_Mips_HIGHEST", 16, 16, 0 },
473 { "fixup_MICROMIPS_HIGHEST",16, 16, 0 },
474 { "fixup_Mips_GOT_HI16", 16, 16, 0 },
475 { "fixup_Mips_GOT_LO16", 16, 16, 0 },
476 { "fixup_Mips_CALL_HI16", 16, 16, 0 },
477 { "fixup_Mips_CALL_LO16", 16, 16, 0 },
478 { "fixup_Mips_PC18_S3", 14, 18, MCFixupKindInfo::FKF_IsPCRel },
479 { "fixup_MIPS_PC19_S2", 13, 19, MCFixupKindInfo::FKF_IsPCRel },
480 { "fixup_MIPS_PC21_S2", 11, 21, MCFixupKindInfo::FKF_IsPCRel },
481 { "fixup_MIPS_PC26_S2", 6, 26, MCFixupKindInfo::FKF_IsPCRel },
482 { "fixup_MIPS_PCHI16", 16, 16, MCFixupKindInfo::FKF_IsPCRel },
483 { "fixup_MIPS_PCLO16", 16, 16, MCFixupKindInfo::FKF_IsPCRel },
484 { "fixup_MICROMIPS_26_S1", 6, 26, 0 },
485 { "fixup_MICROMIPS_HI16", 16, 16, 0 },
486 { "fixup_MICROMIPS_LO16", 16, 16, 0 },
487 { "fixup_MICROMIPS_GOT16", 16, 16, 0 },
488 { "fixup_MICROMIPS_PC7_S1", 9, 7, MCFixupKindInfo::FKF_IsPCRel },
489 { "fixup_MICROMIPS_PC10_S1", 6, 10, MCFixupKindInfo::FKF_IsPCRel },
490 { "fixup_MICROMIPS_PC16_S1",16, 16, MCFixupKindInfo::FKF_IsPCRel },
491 { "fixup_MICROMIPS_PC26_S1", 6, 26, MCFixupKindInfo::FKF_IsPCRel },
492 { "fixup_MICROMIPS_PC19_S2",13, 19, MCFixupKindInfo::FKF_IsPCRel },
493 { "fixup_MICROMIPS_PC18_S3",14, 18, MCFixupKindInfo::FKF_IsPCRel },
494 { "fixup_MICROMIPS_PC21_S1",11, 21, MCFixupKindInfo::FKF_IsPCRel },
495 { "fixup_MICROMIPS_CALL16", 16, 16, 0 },
496 { "fixup_MICROMIPS_GOT_DISP", 16, 16, 0 },
497 { "fixup_MICROMIPS_GOT_PAGE", 16, 16, 0 },
498 { "fixup_MICROMIPS_GOT_OFST", 16, 16, 0 },
499 { "fixup_MICROMIPS_TLS_GD", 16, 16, 0 },
500 { "fixup_MICROMIPS_TLS_LDM", 16, 16, 0 },
501 { "fixup_MICROMIPS_TLS_DTPREL_HI16", 16, 16, 0 },
502 { "fixup_MICROMIPS_TLS_DTPREL_LO16", 16, 16, 0 },
503 { "fixup_MICROMIPS_GOTTPREL", 16, 16, 0 },
504 { "fixup_MICROMIPS_TLS_TPREL_HI16", 16, 16, 0 },
505 { "fixup_MICROMIPS_TLS_TPREL_LO16", 16, 16, 0 },
506 { "fixup_Mips_SUB", 0, 64, 0 },
507 { "fixup_MICROMIPS_SUB", 0, 64, 0 },
508 { "fixup_Mips_JALR", 0, 32, 0 },
509 { "fixup_MICROMIPS_JALR", 0, 32, 0 }
510 };
511 static_assert(std::size(BigEndianInfos) == Mips::NumTargetFixupKinds,
512 "Not all MIPS big endian fixup kinds added!");
513
514 if (Kind >= FirstLiteralRelocationKind)
515 return MCAsmBackend::getFixupKindInfo(FK_NONE);
516 if (Kind < FirstTargetFixupKind)
517 return MCAsmBackend::getFixupKindInfo(Kind);
518
519 assert(unsigned(Kind - FirstTargetFixupKind) < getNumFixupKinds() &&
520 "Invalid kind!");
521
522 if (Endian == llvm::endianness::little)
523 return LittleEndianInfos[Kind - FirstTargetFixupKind];
524 return BigEndianInfos[Kind - FirstTargetFixupKind];
525 }
526
527 /// WriteNopData - Write an (optimal) nop sequence of Count bytes
528 /// to the given output. If the target cannot generate such a sequence,
529 /// it should return an error.
530 ///
531 /// \return - True on success.
writeNopData(raw_ostream & OS,uint64_t Count,const MCSubtargetInfo * STI) const532 bool MipsAsmBackend::writeNopData(raw_ostream &OS, uint64_t Count,
533 const MCSubtargetInfo *STI) const {
534 // Check for a less than instruction size number of bytes
535 // FIXME: 16 bit instructions are not handled yet here.
536 // We shouldn't be using a hard coded number for instruction size.
537
538 // If the count is not 4-byte aligned, we must be writing data into the text
539 // section (otherwise we have unaligned instructions, and thus have far
540 // bigger problems), so just write zeros instead.
541 OS.write_zeros(Count);
542 return true;
543 }
544
shouldForceRelocation(const MCAssembler & Asm,const MCFixup & Fixup,const MCValue & Target,const MCSubtargetInfo * STI)545 bool MipsAsmBackend::shouldForceRelocation(const MCAssembler &Asm,
546 const MCFixup &Fixup,
547 const MCValue &Target,
548 const MCSubtargetInfo *STI) {
549 if (Fixup.getKind() >= FirstLiteralRelocationKind)
550 return true;
551 const unsigned FixupKind = Fixup.getKind();
552 switch (FixupKind) {
553 default:
554 return false;
555 // All these relocations require special processing
556 // at linking time. Delegate this work to a linker.
557 case Mips::fixup_Mips_CALL_HI16:
558 case Mips::fixup_Mips_CALL_LO16:
559 case Mips::fixup_Mips_CALL16:
560 case Mips::fixup_Mips_GOT:
561 case Mips::fixup_Mips_GOT_PAGE:
562 case Mips::fixup_Mips_GOT_OFST:
563 case Mips::fixup_Mips_GOT_DISP:
564 case Mips::fixup_Mips_GOT_HI16:
565 case Mips::fixup_Mips_GOT_LO16:
566 case Mips::fixup_Mips_GOTTPREL:
567 case Mips::fixup_Mips_DTPREL_HI:
568 case Mips::fixup_Mips_DTPREL_LO:
569 case Mips::fixup_Mips_TLSGD:
570 case Mips::fixup_Mips_TLSLDM:
571 case Mips::fixup_Mips_TPREL_HI:
572 case Mips::fixup_Mips_TPREL_LO:
573 case Mips::fixup_Mips_JALR:
574 case Mips::fixup_MICROMIPS_CALL16:
575 case Mips::fixup_MICROMIPS_GOT_DISP:
576 case Mips::fixup_MICROMIPS_GOT_PAGE:
577 case Mips::fixup_MICROMIPS_GOT_OFST:
578 case Mips::fixup_MICROMIPS_GOT16:
579 case Mips::fixup_MICROMIPS_GOTTPREL:
580 case Mips::fixup_MICROMIPS_TLS_DTPREL_HI16:
581 case Mips::fixup_MICROMIPS_TLS_DTPREL_LO16:
582 case Mips::fixup_MICROMIPS_TLS_GD:
583 case Mips::fixup_MICROMIPS_TLS_LDM:
584 case Mips::fixup_MICROMIPS_TLS_TPREL_HI16:
585 case Mips::fixup_MICROMIPS_TLS_TPREL_LO16:
586 case Mips::fixup_MICROMIPS_JALR:
587 return true;
588 }
589 }
590
isMicroMips(const MCSymbol * Sym) const591 bool MipsAsmBackend::isMicroMips(const MCSymbol *Sym) const {
592 if (const auto *ElfSym = dyn_cast<const MCSymbolELF>(Sym)) {
593 if (ElfSym->getOther() & ELF::STO_MIPS_MICROMIPS)
594 return true;
595 }
596 return false;
597 }
598
createMipsAsmBackend(const Target & T,const MCSubtargetInfo & STI,const MCRegisterInfo & MRI,const MCTargetOptions & Options)599 MCAsmBackend *llvm::createMipsAsmBackend(const Target &T,
600 const MCSubtargetInfo &STI,
601 const MCRegisterInfo &MRI,
602 const MCTargetOptions &Options) {
603 MipsABIInfo ABI = MipsABIInfo::computeTargetABI(STI.getTargetTriple(),
604 STI.getCPU(), Options);
605 return new MipsAsmBackend(T, MRI, STI.getTargetTriple(), STI.getCPU(),
606 ABI.IsN32());
607 }
608