1 //===-- MipsAsmBackend.cpp - Mips Asm Backend ----------------------------===//
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 implements the MipsAsmBackend class.
12 //===----------------------------------------------------------------------===//
15 #include "MCTargetDesc/MipsFixupKinds.h"
16 #include "MCTargetDesc/MipsAsmBackend.h"
17 #include "MCTargetDesc/MipsMCTargetDesc.h"
18 #include "llvm/MC/MCAsmBackend.h"
19 #include "llvm/MC/MCAssembler.h"
20 #include "llvm/MC/MCContext.h"
21 #include "llvm/MC/MCDirectives.h"
22 #include "llvm/MC/MCELFObjectWriter.h"
23 #include "llvm/MC/MCFixupKindInfo.h"
24 #include "llvm/MC/MCObjectWriter.h"
25 #include "llvm/MC/MCSubtargetInfo.h"
26 #include "llvm/Support/ErrorHandling.h"
27 #include "llvm/Support/MathExtras.h"
28 #include "llvm/Support/raw_ostream.h"
32 // Prepare value for the target space for it
33 static unsigned adjustFixupValue(const MCFixup &Fixup, uint64_t Value,
34 MCContext *Ctx = nullptr) {
36 unsigned Kind = Fixup.getKind();
38 // Add/subtract and shift
46 case Mips::fixup_Mips_LO16:
47 case Mips::fixup_Mips_GPREL16:
48 case Mips::fixup_Mips_GPOFF_HI:
49 case Mips::fixup_Mips_GPOFF_LO:
50 case Mips::fixup_Mips_GOT_PAGE:
51 case Mips::fixup_Mips_GOT_OFST:
52 case Mips::fixup_Mips_GOT_DISP:
53 case Mips::fixup_Mips_GOT_LO16:
54 case Mips::fixup_Mips_CALL_LO16:
55 case Mips::fixup_MICROMIPS_LO16:
56 case Mips::fixup_MICROMIPS_GOT_PAGE:
57 case Mips::fixup_MICROMIPS_GOT_OFST:
58 case Mips::fixup_MICROMIPS_GOT_DISP:
60 case Mips::fixup_Mips_PC16:
61 // So far we are only using this type for branches.
62 // For branches we start 1 instruction after the branch
63 // so the displacement will be one instruction size less.
65 // The displacement is then divided by 4 to give us an 18 bit
66 // address range. Forcing a signed division because Value can be negative.
67 Value = (int64_t)Value / 4;
68 // We now check if Value can be encoded as a 16-bit signed immediate.
69 if (!isIntN(16, Value) && Ctx)
70 Ctx->FatalError(Fixup.getLoc(), "out of range PC16 fixup");
72 case Mips::fixup_Mips_26:
73 // So far we are only using this type for jumps.
74 // The displacement is then divided by 4 to give us an 28 bit
78 case Mips::fixup_Mips_HI16:
79 case Mips::fixup_Mips_GOT_Local:
80 case Mips::fixup_Mips_GOT_HI16:
81 case Mips::fixup_Mips_CALL_HI16:
82 case Mips::fixup_MICROMIPS_HI16:
83 // Get the 2nd 16-bits. Also add 1 if bit 15 is 1.
84 Value = ((Value + 0x8000) >> 16) & 0xffff;
86 case Mips::fixup_Mips_HIGHER:
87 // Get the 3rd 16-bits.
88 Value = ((Value + 0x80008000LL) >> 32) & 0xffff;
90 case Mips::fixup_Mips_HIGHEST:
91 // Get the 4th 16-bits.
92 Value = ((Value + 0x800080008000LL) >> 48) & 0xffff;
94 case Mips::fixup_MICROMIPS_26_S1:
97 case Mips::fixup_MICROMIPS_PC16_S1:
99 // Forcing a signed division because Value can be negative.
100 Value = (int64_t)Value / 2;
101 // We now check if Value can be encoded as a 16-bit signed immediate.
102 if (!isIntN(16, Value) && Ctx)
103 Ctx->FatalError(Fixup.getLoc(), "out of range PC16 fixup");
105 case Mips::fixup_MIPS_PC21_S2:
107 // Forcing a signed division because Value can be negative.
108 Value = (int64_t) Value / 4;
109 // We now check if Value can be encoded as a 21-bit signed immediate.
110 if (!isIntN(21, Value) && Ctx)
111 Ctx->FatalError(Fixup.getLoc(), "out of range PC21 fixup");
113 case Mips::fixup_MIPS_PC26_S2:
115 // Forcing a signed division because Value can be negative.
116 Value = (int64_t) Value / 4;
117 // We now check if Value can be encoded as a 26-bit signed immediate.
118 if (!isIntN(26, Value) && Ctx)
119 Ctx->FatalError(Fixup.getLoc(), "out of range PC26 fixup");
126 MCObjectWriter *MipsAsmBackend::createObjectWriter(raw_ostream &OS) const {
127 return createMipsELFObjectWriter(OS,
128 MCELFObjectTargetWriter::getOSABI(OSType), IsLittle, Is64Bit);
131 // Little-endian fixup data byte ordering:
132 // mips32r2: a | b | x | x
133 // microMIPS: x | x | a | b
135 static bool needsMMLEByteOrder(unsigned Kind) {
136 return Kind >= Mips::fixup_MICROMIPS_26_S1 &&
137 Kind < Mips::LastTargetFixupKind;
140 // Calculate index for microMIPS specific little endian byte order
141 static unsigned calculateMMLEIndex(unsigned i) {
142 assert(i <= 3 && "Index out of range!");
144 return (1 - i / 2) * 2 + i % 2;
147 /// ApplyFixup - Apply the \p Value for given \p Fixup into the provided
148 /// data fragment, at the offset specified by the fixup and following the
149 /// fixup kind as appropriate.
150 void MipsAsmBackend::applyFixup(const MCFixup &Fixup, char *Data,
151 unsigned DataSize, uint64_t Value,
152 bool IsPCRel) const {
153 MCFixupKind Kind = Fixup.getKind();
154 Value = adjustFixupValue(Fixup, Value);
157 return; // Doesn't change encoding.
159 // Where do we start in the object
160 unsigned Offset = Fixup.getOffset();
161 // Number of bytes we need to fixup
162 unsigned NumBytes = (getFixupKindInfo(Kind).TargetSize + 7) / 8;
163 // Used to point to big endian bytes
166 switch ((unsigned)Kind) {
168 case Mips::fixup_Mips_16:
172 case Mips::fixup_Mips_64:
181 // Grab current value, if any, from bits.
184 bool microMipsLEByteOrder = needsMMLEByteOrder((unsigned) Kind);
186 for (unsigned i = 0; i != NumBytes; ++i) {
187 unsigned Idx = IsLittle ? (microMipsLEByteOrder ? calculateMMLEIndex(i)
189 : (FullSize - 1 - i);
190 CurVal |= (uint64_t)((uint8_t)Data[Offset + Idx]) << (i*8);
193 uint64_t Mask = ((uint64_t)(-1) >>
194 (64 - getFixupKindInfo(Kind).TargetSize));
195 CurVal |= Value & Mask;
197 // Write out the fixed up bytes back to the code/data bits.
198 for (unsigned i = 0; i != NumBytes; ++i) {
199 unsigned Idx = IsLittle ? (microMipsLEByteOrder ? calculateMMLEIndex(i)
201 : (FullSize - 1 - i);
202 Data[Offset + Idx] = (uint8_t)((CurVal >> (i*8)) & 0xff);
206 const MCFixupKindInfo &MipsAsmBackend::
207 getFixupKindInfo(MCFixupKind Kind) const {
208 const static MCFixupKindInfo LittleEndianInfos[Mips::NumTargetFixupKinds] = {
209 // This table *must* be in same the order of fixup_* kinds in
212 // name offset bits flags
213 { "fixup_Mips_16", 0, 16, 0 },
214 { "fixup_Mips_32", 0, 32, 0 },
215 { "fixup_Mips_REL32", 0, 32, 0 },
216 { "fixup_Mips_26", 0, 26, 0 },
217 { "fixup_Mips_HI16", 0, 16, 0 },
218 { "fixup_Mips_LO16", 0, 16, 0 },
219 { "fixup_Mips_GPREL16", 0, 16, 0 },
220 { "fixup_Mips_LITERAL", 0, 16, 0 },
221 { "fixup_Mips_GOT_Global", 0, 16, 0 },
222 { "fixup_Mips_GOT_Local", 0, 16, 0 },
223 { "fixup_Mips_PC16", 0, 16, MCFixupKindInfo::FKF_IsPCRel },
224 { "fixup_Mips_CALL16", 0, 16, 0 },
225 { "fixup_Mips_GPREL32", 0, 32, 0 },
226 { "fixup_Mips_SHIFT5", 6, 5, 0 },
227 { "fixup_Mips_SHIFT6", 6, 5, 0 },
228 { "fixup_Mips_64", 0, 64, 0 },
229 { "fixup_Mips_TLSGD", 0, 16, 0 },
230 { "fixup_Mips_GOTTPREL", 0, 16, 0 },
231 { "fixup_Mips_TPREL_HI", 0, 16, 0 },
232 { "fixup_Mips_TPREL_LO", 0, 16, 0 },
233 { "fixup_Mips_TLSLDM", 0, 16, 0 },
234 { "fixup_Mips_DTPREL_HI", 0, 16, 0 },
235 { "fixup_Mips_DTPREL_LO", 0, 16, 0 },
236 { "fixup_Mips_Branch_PCRel", 0, 16, MCFixupKindInfo::FKF_IsPCRel },
237 { "fixup_Mips_GPOFF_HI", 0, 16, 0 },
238 { "fixup_Mips_GPOFF_LO", 0, 16, 0 },
239 { "fixup_Mips_GOT_PAGE", 0, 16, 0 },
240 { "fixup_Mips_GOT_OFST", 0, 16, 0 },
241 { "fixup_Mips_GOT_DISP", 0, 16, 0 },
242 { "fixup_Mips_HIGHER", 0, 16, 0 },
243 { "fixup_Mips_HIGHEST", 0, 16, 0 },
244 { "fixup_Mips_GOT_HI16", 0, 16, 0 },
245 { "fixup_Mips_GOT_LO16", 0, 16, 0 },
246 { "fixup_Mips_CALL_HI16", 0, 16, 0 },
247 { "fixup_Mips_CALL_LO16", 0, 16, 0 },
248 { "fixup_MIPS_PC21_S2", 0, 21, MCFixupKindInfo::FKF_IsPCRel },
249 { "fixup_MIPS_PC26_S2", 0, 26, MCFixupKindInfo::FKF_IsPCRel },
250 { "fixup_MICROMIPS_26_S1", 0, 26, 0 },
251 { "fixup_MICROMIPS_HI16", 0, 16, 0 },
252 { "fixup_MICROMIPS_LO16", 0, 16, 0 },
253 { "fixup_MICROMIPS_GOT16", 0, 16, 0 },
254 { "fixup_MICROMIPS_PC16_S1", 0, 16, MCFixupKindInfo::FKF_IsPCRel },
255 { "fixup_MICROMIPS_CALL16", 0, 16, 0 },
256 { "fixup_MICROMIPS_GOT_DISP", 0, 16, 0 },
257 { "fixup_MICROMIPS_GOT_PAGE", 0, 16, 0 },
258 { "fixup_MICROMIPS_GOT_OFST", 0, 16, 0 },
259 { "fixup_MICROMIPS_TLS_GD", 0, 16, 0 },
260 { "fixup_MICROMIPS_TLS_LDM", 0, 16, 0 },
261 { "fixup_MICROMIPS_TLS_DTPREL_HI16", 0, 16, 0 },
262 { "fixup_MICROMIPS_TLS_DTPREL_LO16", 0, 16, 0 },
263 { "fixup_MICROMIPS_TLS_TPREL_HI16", 0, 16, 0 },
264 { "fixup_MICROMIPS_TLS_TPREL_LO16", 0, 16, 0 }
267 const static MCFixupKindInfo BigEndianInfos[Mips::NumTargetFixupKinds] = {
268 // This table *must* be in same the order of fixup_* kinds in
271 // name offset bits flags
272 { "fixup_Mips_16", 16, 16, 0 },
273 { "fixup_Mips_32", 0, 32, 0 },
274 { "fixup_Mips_REL32", 0, 32, 0 },
275 { "fixup_Mips_26", 6, 26, 0 },
276 { "fixup_Mips_HI16", 16, 16, 0 },
277 { "fixup_Mips_LO16", 16, 16, 0 },
278 { "fixup_Mips_GPREL16", 16, 16, 0 },
279 { "fixup_Mips_LITERAL", 16, 16, 0 },
280 { "fixup_Mips_GOT_Global", 16, 16, 0 },
281 { "fixup_Mips_GOT_Local", 16, 16, 0 },
282 { "fixup_Mips_PC16", 16, 16, MCFixupKindInfo::FKF_IsPCRel },
283 { "fixup_Mips_CALL16", 16, 16, 0 },
284 { "fixup_Mips_GPREL32", 0, 32, 0 },
285 { "fixup_Mips_SHIFT5", 21, 5, 0 },
286 { "fixup_Mips_SHIFT6", 21, 5, 0 },
287 { "fixup_Mips_64", 0, 64, 0 },
288 { "fixup_Mips_TLSGD", 16, 16, 0 },
289 { "fixup_Mips_GOTTPREL", 16, 16, 0 },
290 { "fixup_Mips_TPREL_HI", 16, 16, 0 },
291 { "fixup_Mips_TPREL_LO", 16, 16, 0 },
292 { "fixup_Mips_TLSLDM", 16, 16, 0 },
293 { "fixup_Mips_DTPREL_HI", 16, 16, 0 },
294 { "fixup_Mips_DTPREL_LO", 16, 16, 0 },
295 { "fixup_Mips_Branch_PCRel",16, 16, MCFixupKindInfo::FKF_IsPCRel },
296 { "fixup_Mips_GPOFF_HI", 16, 16, 0 },
297 { "fixup_Mips_GPOFF_LO", 16, 16, 0 },
298 { "fixup_Mips_GOT_PAGE", 16, 16, 0 },
299 { "fixup_Mips_GOT_OFST", 16, 16, 0 },
300 { "fixup_Mips_GOT_DISP", 16, 16, 0 },
301 { "fixup_Mips_HIGHER", 16, 16, 0 },
302 { "fixup_Mips_HIGHEST", 16, 16, 0 },
303 { "fixup_Mips_GOT_HI16", 16, 16, 0 },
304 { "fixup_Mips_GOT_LO16", 16, 16, 0 },
305 { "fixup_Mips_CALL_HI16", 16, 16, 0 },
306 { "fixup_Mips_CALL_LO16", 16, 16, 0 },
307 { "fixup_MIPS_PC21_S2", 11, 21, MCFixupKindInfo::FKF_IsPCRel },
308 { "fixup_MIPS_PC26_S2", 6, 26, MCFixupKindInfo::FKF_IsPCRel },
309 { "fixup_MICROMIPS_26_S1", 6, 26, 0 },
310 { "fixup_MICROMIPS_HI16", 16, 16, 0 },
311 { "fixup_MICROMIPS_LO16", 16, 16, 0 },
312 { "fixup_MICROMIPS_GOT16", 16, 16, 0 },
313 { "fixup_MICROMIPS_PC16_S1",16, 16, MCFixupKindInfo::FKF_IsPCRel },
314 { "fixup_MICROMIPS_CALL16", 16, 16, 0 },
315 { "fixup_MICROMIPS_GOT_DISP", 16, 16, 0 },
316 { "fixup_MICROMIPS_GOT_PAGE", 16, 16, 0 },
317 { "fixup_MICROMIPS_GOT_OFST", 16, 16, 0 },
318 { "fixup_MICROMIPS_TLS_GD", 16, 16, 0 },
319 { "fixup_MICROMIPS_TLS_LDM", 16, 16, 0 },
320 { "fixup_MICROMIPS_TLS_DTPREL_HI16", 16, 16, 0 },
321 { "fixup_MICROMIPS_TLS_DTPREL_LO16", 16, 16, 0 },
322 { "fixup_MICROMIPS_TLS_TPREL_HI16", 16, 16, 0 },
323 { "fixup_MICROMIPS_TLS_TPREL_LO16", 16, 16, 0 }
326 if (Kind < FirstTargetFixupKind)
327 return MCAsmBackend::getFixupKindInfo(Kind);
329 assert(unsigned(Kind - FirstTargetFixupKind) < getNumFixupKinds() &&
333 return LittleEndianInfos[Kind - FirstTargetFixupKind];
334 return BigEndianInfos[Kind - FirstTargetFixupKind];
337 /// WriteNopData - Write an (optimal) nop sequence of Count bytes
338 /// to the given output. If the target cannot generate such a sequence,
339 /// it should return an error.
341 /// \return - True on success.
342 bool MipsAsmBackend::writeNopData(uint64_t Count, MCObjectWriter *OW) const {
343 // Check for a less than instruction size number of bytes
344 // FIXME: 16 bit instructions are not handled yet here.
345 // We shouldn't be using a hard coded number for instruction size.
346 if (Count % 4) return false;
348 uint64_t NumNops = Count / 4;
349 for (uint64_t i = 0; i != NumNops; ++i)
354 /// processFixupValue - Target hook to process the literal value of a fixup
356 void MipsAsmBackend::processFixupValue(const MCAssembler &Asm,
357 const MCAsmLayout &Layout,
358 const MCFixup &Fixup,
359 const MCFragment *DF,
360 const MCValue &Target,
363 // At this point we'll ignore the value returned by adjustFixupValue as
364 // we are only checking if the fixup can be applied correctly. We have
365 // access to MCContext from here which allows us to report a fatal error
366 // with *possibly* a source code location.
367 (void)adjustFixupValue(Fixup, Value, &Asm.getContext());
371 MCAsmBackend *llvm::createMipsAsmBackendEL32(const Target &T,
372 const MCRegisterInfo &MRI,
375 return new MipsAsmBackend(T, Triple(TT).getOS(),
376 /*IsLittle*/true, /*Is64Bit*/false);
379 MCAsmBackend *llvm::createMipsAsmBackendEB32(const Target &T,
380 const MCRegisterInfo &MRI,
383 return new MipsAsmBackend(T, Triple(TT).getOS(),
384 /*IsLittle*/false, /*Is64Bit*/false);
387 MCAsmBackend *llvm::createMipsAsmBackendEL64(const Target &T,
388 const MCRegisterInfo &MRI,
391 return new MipsAsmBackend(T, Triple(TT).getOS(),
392 /*IsLittle*/true, /*Is64Bit*/true);
395 MCAsmBackend *llvm::createMipsAsmBackendEB64(const Target &T,
396 const MCRegisterInfo &MRI,
399 return new MipsAsmBackend(T, Triple(TT).getOS(),
400 /*IsLittle*/false, /*Is64Bit*/true);