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1 //===-- HexagonAsmBackend.cpp - Hexagon Assembler Backend -----------------===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 
10 #include "Hexagon.h"
11 #include "HexagonFixupKinds.h"
12 #include "HexagonMCTargetDesc.h"
13 #include "MCTargetDesc/HexagonBaseInfo.h"
14 #include "MCTargetDesc/HexagonMCChecker.h"
15 #include "MCTargetDesc/HexagonMCCodeEmitter.h"
16 #include "MCTargetDesc/HexagonMCInstrInfo.h"
17 #include "MCTargetDesc/HexagonMCShuffler.h"
18 #include "llvm/MC/MCAsmBackend.h"
19 #include "llvm/MC/MCAsmLayout.h"
20 #include "llvm/MC/MCAssembler.h"
21 #include "llvm/MC/MCContext.h"
22 #include "llvm/MC/MCELFObjectWriter.h"
23 #include "llvm/MC/MCFixupKindInfo.h"
24 #include "llvm/MC/MCInstrInfo.h"
25 #include "llvm/MC/MCObjectWriter.h"
26 #include "llvm/Support/Debug.h"
27 #include "llvm/Support/TargetRegistry.h"
28 
29 #include <sstream>
30 
31 using namespace llvm;
32 using namespace Hexagon;
33 
34 #define DEBUG_TYPE "hexagon-asm-backend"
35 
36 static cl::opt<bool> DisableFixup
37   ("mno-fixup", cl::desc("Disable fixing up resolved relocations for Hexagon"));
38 
39 namespace {
40 
41 class HexagonAsmBackend : public MCAsmBackend {
42   uint8_t OSABI;
43   StringRef CPU;
44   mutable uint64_t relaxedCnt;
45   std::unique_ptr <MCInstrInfo> MCII;
46   std::unique_ptr <MCInst *> RelaxTarget;
47   MCInst * Extender;
48 
ReplaceInstruction(MCCodeEmitter & E,MCRelaxableFragment & RF,MCInst & HMB) const49   void ReplaceInstruction(MCCodeEmitter &E, MCRelaxableFragment &RF,
50                           MCInst &HMB) const {
51     SmallVector<MCFixup, 4> Fixups;
52     SmallString<256> Code;
53     raw_svector_ostream VecOS(Code);
54     E.encodeInstruction(HMB, VecOS, Fixups, RF.getSubtargetInfo());
55 
56     // Update the fragment.
57     RF.setInst(HMB);
58     RF.getContents() = Code;
59     RF.getFixups() = Fixups;
60   }
61 public:
HexagonAsmBackend(const Target & T,uint8_t OSABI,StringRef CPU)62   HexagonAsmBackend(const Target &T, uint8_t OSABI, StringRef CPU) :
63     OSABI(OSABI), MCII (T.createMCInstrInfo()), RelaxTarget(new MCInst *),
64     Extender(nullptr) {}
65 
createObjectWriter(raw_pwrite_stream & OS) const66   MCObjectWriter *createObjectWriter(raw_pwrite_stream &OS) const override {
67     return createHexagonELFObjectWriter(OS, OSABI, CPU);
68   }
69 
setExtender(MCContext & Context) const70   void setExtender(MCContext &Context) const {
71     if (Extender == nullptr)
72       const_cast<HexagonAsmBackend *>(this)->Extender = new (Context) MCInst;
73   }
74 
takeExtender() const75   MCInst *takeExtender() const {
76     assert(Extender != nullptr);
77     MCInst * Result = Extender;
78     const_cast<HexagonAsmBackend *>(this)->Extender = nullptr;
79     return Result;
80   }
81 
getNumFixupKinds() const82   unsigned getNumFixupKinds() const override {
83     return Hexagon::NumTargetFixupKinds;
84   }
85 
getFixupKindInfo(MCFixupKind Kind) const86   const MCFixupKindInfo &getFixupKindInfo(MCFixupKind Kind) const override {
87     const static MCFixupKindInfo Infos[Hexagon::NumTargetFixupKinds] = {
88       // This table *must* be in same the order of fixup_* kinds in
89       // HexagonFixupKinds.h.
90       //
91       // namei                          offset  bits  flags
92       { "fixup_Hexagon_B22_PCREL",        0,    32,   MCFixupKindInfo::FKF_IsPCRel },
93       { "fixup_Hexagon_B15_PCREL",        0,    32,   MCFixupKindInfo::FKF_IsPCRel },
94       { "fixup_Hexagon_B7_PCREL",         0,    32,   MCFixupKindInfo::FKF_IsPCRel },
95       { "fixup_Hexagon_LO16",             0,    32,   0 },
96       { "fixup_Hexagon_HI16",             0,    32,   0 },
97       { "fixup_Hexagon_32",               0,    32,   0 },
98       { "fixup_Hexagon_16",               0,    32,   0 },
99       { "fixup_Hexagon_8",                0,    32,   0 },
100       { "fixup_Hexagon_GPREL16_0",        0,    32,   0 },
101       { "fixup_Hexagon_GPREL16_1",        0,    32,   0 },
102       { "fixup_Hexagon_GPREL16_2",        0,    32,   0 },
103       { "fixup_Hexagon_GPREL16_3",        0,    32,   0 },
104       { "fixup_Hexagon_HL16",             0,    32,   0 },
105       { "fixup_Hexagon_B13_PCREL",        0,    32,   MCFixupKindInfo::FKF_IsPCRel },
106       { "fixup_Hexagon_B9_PCREL",         0,    32,   MCFixupKindInfo::FKF_IsPCRel },
107       { "fixup_Hexagon_B32_PCREL_X",      0,    32,   MCFixupKindInfo::FKF_IsPCRel },
108       { "fixup_Hexagon_32_6_X",           0,    32,   0 },
109       { "fixup_Hexagon_B22_PCREL_X",      0,    32,   MCFixupKindInfo::FKF_IsPCRel },
110       { "fixup_Hexagon_B15_PCREL_X",      0,    32,   MCFixupKindInfo::FKF_IsPCRel },
111       { "fixup_Hexagon_B13_PCREL_X",      0,    32,   MCFixupKindInfo::FKF_IsPCRel },
112       { "fixup_Hexagon_B9_PCREL_X",       0,    32,   MCFixupKindInfo::FKF_IsPCRel },
113       { "fixup_Hexagon_B7_PCREL_X",       0,    32,   MCFixupKindInfo::FKF_IsPCRel },
114       { "fixup_Hexagon_16_X",             0,    32,   0 },
115       { "fixup_Hexagon_12_X",             0,    32,   0 },
116       { "fixup_Hexagon_11_X",             0,    32,   0 },
117       { "fixup_Hexagon_10_X",             0,    32,   0 },
118       { "fixup_Hexagon_9_X",              0,    32,   0 },
119       { "fixup_Hexagon_8_X",              0,    32,   0 },
120       { "fixup_Hexagon_7_X",              0,    32,   0 },
121       { "fixup_Hexagon_6_X",              0,    32,   0 },
122       { "fixup_Hexagon_32_PCREL",         0,    32,   MCFixupKindInfo::FKF_IsPCRel },
123       { "fixup_Hexagon_COPY",             0,    32,   0 },
124       { "fixup_Hexagon_GLOB_DAT",         0,    32,   0 },
125       { "fixup_Hexagon_JMP_SLOT",         0,    32,   0 },
126       { "fixup_Hexagon_RELATIVE",         0,    32,   0 },
127       { "fixup_Hexagon_PLT_B22_PCREL",    0,    32,   MCFixupKindInfo::FKF_IsPCRel },
128       { "fixup_Hexagon_GOTREL_LO16",      0,    32,   0 },
129       { "fixup_Hexagon_GOTREL_HI16",      0,    32,   0 },
130       { "fixup_Hexagon_GOTREL_32",        0,    32,   0 },
131       { "fixup_Hexagon_GOT_LO16",         0,    32,   0 },
132       { "fixup_Hexagon_GOT_HI16",         0,    32,   0 },
133       { "fixup_Hexagon_GOT_32",           0,    32,   0 },
134       { "fixup_Hexagon_GOT_16",           0,    32,   0 },
135       { "fixup_Hexagon_DTPMOD_32",        0,    32,   0 },
136       { "fixup_Hexagon_DTPREL_LO16",      0,    32,   0 },
137       { "fixup_Hexagon_DTPREL_HI16",      0,    32,   0 },
138       { "fixup_Hexagon_DTPREL_32",        0,    32,   0 },
139       { "fixup_Hexagon_DTPREL_16",        0,    32,   0 },
140       { "fixup_Hexagon_GD_PLT_B22_PCREL", 0,    32,   MCFixupKindInfo::FKF_IsPCRel },
141       { "fixup_Hexagon_LD_PLT_B22_PCREL", 0,    32,   MCFixupKindInfo::FKF_IsPCRel },
142       { "fixup_Hexagon_GD_GOT_LO16",      0,    32,   0 },
143       { "fixup_Hexagon_GD_GOT_HI16",      0,    32,   0 },
144       { "fixup_Hexagon_GD_GOT_32",        0,    32,   0 },
145       { "fixup_Hexagon_GD_GOT_16",        0,    32,   0 },
146       { "fixup_Hexagon_LD_GOT_LO16",      0,    32,   0 },
147       { "fixup_Hexagon_LD_GOT_HI16",      0,    32,   0 },
148       { "fixup_Hexagon_LD_GOT_32",        0,    32,   0 },
149       { "fixup_Hexagon_LD_GOT_16",        0,    32,   0 },
150       { "fixup_Hexagon_IE_LO16",          0,    32,   0 },
151       { "fixup_Hexagon_IE_HI16",          0,    32,   0 },
152       { "fixup_Hexagon_IE_32",            0,    32,   0 },
153       { "fixup_Hexagon_IE_16",            0,    32,   0 },
154       { "fixup_Hexagon_IE_GOT_LO16",      0,    32,   0 },
155       { "fixup_Hexagon_IE_GOT_HI16",      0,    32,   0 },
156       { "fixup_Hexagon_IE_GOT_32",        0,    32,   0 },
157       { "fixup_Hexagon_IE_GOT_16",        0,    32,   0 },
158       { "fixup_Hexagon_TPREL_LO16",       0,    32,   0 },
159       { "fixup_Hexagon_TPREL_HI16",       0,    32,   0 },
160       { "fixup_Hexagon_TPREL_32",         0,    32,   0 },
161       { "fixup_Hexagon_TPREL_16",         0,    32,   0 },
162       { "fixup_Hexagon_6_PCREL_X",        0,    32,   MCFixupKindInfo::FKF_IsPCRel },
163       { "fixup_Hexagon_GOTREL_32_6_X",    0,    32,   0 },
164       { "fixup_Hexagon_GOTREL_16_X",      0,    32,   0 },
165       { "fixup_Hexagon_GOTREL_11_X",      0,    32,   0 },
166       { "fixup_Hexagon_GOT_32_6_X",       0,    32,   0 },
167       { "fixup_Hexagon_GOT_16_X",         0,    32,   0 },
168       { "fixup_Hexagon_GOT_11_X",         0,    32,   0 },
169       { "fixup_Hexagon_DTPREL_32_6_X",    0,    32,   0 },
170       { "fixup_Hexagon_DTPREL_16_X",      0,    32,   0 },
171       { "fixup_Hexagon_DTPREL_11_X",      0,    32,   0 },
172       { "fixup_Hexagon_GD_GOT_32_6_X",    0,    32,   0 },
173       { "fixup_Hexagon_GD_GOT_16_X",      0,    32,   0 },
174       { "fixup_Hexagon_GD_GOT_11_X",      0,    32,   0 },
175       { "fixup_Hexagon_LD_GOT_32_6_X",    0,    32,   0 },
176       { "fixup_Hexagon_LD_GOT_16_X",      0,    32,   0 },
177       { "fixup_Hexagon_LD_GOT_11_X",      0,    32,   0 },
178       { "fixup_Hexagon_IE_32_6_X",        0,    32,   0 },
179       { "fixup_Hexagon_IE_16_X",          0,    32,   0 },
180       { "fixup_Hexagon_IE_GOT_32_6_X",    0,    32,   0 },
181       { "fixup_Hexagon_IE_GOT_16_X",      0,    32,   0 },
182       { "fixup_Hexagon_IE_GOT_11_X",      0,    32,   0 },
183       { "fixup_Hexagon_TPREL_32_6_X",     0,    32,   0 },
184       { "fixup_Hexagon_TPREL_16_X",       0,    32,   0 },
185       { "fixup_Hexagon_TPREL_11_X",       0,    32,   0 }
186     };
187 
188     if (Kind < FirstTargetFixupKind)
189       return MCAsmBackend::getFixupKindInfo(Kind);
190 
191     assert(unsigned(Kind - FirstTargetFixupKind) < getNumFixupKinds() &&
192            "Invalid kind!");
193     return Infos[Kind - FirstTargetFixupKind];
194   }
195 
196   /// processFixupValue - Target hook to adjust the literal value of a fixup
197   /// if necessary. IsResolved signals whether the caller believes a relocation
198   /// is needed; the target can modify the value. The default does nothing.
processFixupValue(const MCAssembler & Asm,const MCAsmLayout & Layout,const MCFixup & Fixup,const MCFragment * DF,const MCValue & Target,uint64_t & Value,bool & IsResolved)199   void processFixupValue(const MCAssembler &Asm, const MCAsmLayout &Layout,
200                          const MCFixup &Fixup, const MCFragment *DF,
201                          const MCValue &Target, uint64_t &Value,
202                          bool &IsResolved) override {
203     MCFixupKind Kind = Fixup.getKind();
204 
205     switch((unsigned)Kind) {
206       default:
207         llvm_unreachable("Unknown Fixup Kind!");
208 
209       case fixup_Hexagon_LO16:
210       case fixup_Hexagon_HI16:
211       case fixup_Hexagon_16:
212       case fixup_Hexagon_8:
213       case fixup_Hexagon_GPREL16_0:
214       case fixup_Hexagon_GPREL16_1:
215       case fixup_Hexagon_GPREL16_2:
216       case fixup_Hexagon_GPREL16_3:
217       case fixup_Hexagon_HL16:
218       case fixup_Hexagon_32_6_X:
219       case fixup_Hexagon_16_X:
220       case fixup_Hexagon_12_X:
221       case fixup_Hexagon_11_X:
222       case fixup_Hexagon_10_X:
223       case fixup_Hexagon_9_X:
224       case fixup_Hexagon_8_X:
225       case fixup_Hexagon_7_X:
226       case fixup_Hexagon_6_X:
227       case fixup_Hexagon_COPY:
228       case fixup_Hexagon_GLOB_DAT:
229       case fixup_Hexagon_JMP_SLOT:
230       case fixup_Hexagon_RELATIVE:
231       case fixup_Hexagon_PLT_B22_PCREL:
232       case fixup_Hexagon_GOTREL_LO16:
233       case fixup_Hexagon_GOTREL_HI16:
234       case fixup_Hexagon_GOTREL_32:
235       case fixup_Hexagon_GOT_LO16:
236       case fixup_Hexagon_GOT_HI16:
237       case fixup_Hexagon_GOT_32:
238       case fixup_Hexagon_GOT_16:
239       case fixup_Hexagon_DTPMOD_32:
240       case fixup_Hexagon_DTPREL_LO16:
241       case fixup_Hexagon_DTPREL_HI16:
242       case fixup_Hexagon_DTPREL_32:
243       case fixup_Hexagon_DTPREL_16:
244       case fixup_Hexagon_GD_PLT_B22_PCREL:
245       case fixup_Hexagon_LD_PLT_B22_PCREL:
246       case fixup_Hexagon_GD_GOT_LO16:
247       case fixup_Hexagon_GD_GOT_HI16:
248       case fixup_Hexagon_GD_GOT_32:
249       case fixup_Hexagon_GD_GOT_16:
250       case fixup_Hexagon_LD_GOT_LO16:
251       case fixup_Hexagon_LD_GOT_HI16:
252       case fixup_Hexagon_LD_GOT_32:
253       case fixup_Hexagon_LD_GOT_16:
254       case fixup_Hexagon_IE_LO16:
255       case fixup_Hexagon_IE_HI16:
256       case fixup_Hexagon_IE_32:
257       case fixup_Hexagon_IE_16:
258       case fixup_Hexagon_IE_GOT_LO16:
259       case fixup_Hexagon_IE_GOT_HI16:
260       case fixup_Hexagon_IE_GOT_32:
261       case fixup_Hexagon_IE_GOT_16:
262       case fixup_Hexagon_TPREL_LO16:
263       case fixup_Hexagon_TPREL_HI16:
264       case fixup_Hexagon_TPREL_32:
265       case fixup_Hexagon_TPREL_16:
266       case fixup_Hexagon_GOTREL_32_6_X:
267       case fixup_Hexagon_GOTREL_16_X:
268       case fixup_Hexagon_GOTREL_11_X:
269       case fixup_Hexagon_GOT_32_6_X:
270       case fixup_Hexagon_GOT_16_X:
271       case fixup_Hexagon_GOT_11_X:
272       case fixup_Hexagon_DTPREL_32_6_X:
273       case fixup_Hexagon_DTPREL_16_X:
274       case fixup_Hexagon_DTPREL_11_X:
275       case fixup_Hexagon_GD_GOT_32_6_X:
276       case fixup_Hexagon_GD_GOT_16_X:
277       case fixup_Hexagon_GD_GOT_11_X:
278       case fixup_Hexagon_LD_GOT_32_6_X:
279       case fixup_Hexagon_LD_GOT_16_X:
280       case fixup_Hexagon_LD_GOT_11_X:
281       case fixup_Hexagon_IE_32_6_X:
282       case fixup_Hexagon_IE_16_X:
283       case fixup_Hexagon_IE_GOT_32_6_X:
284       case fixup_Hexagon_IE_GOT_16_X:
285       case fixup_Hexagon_IE_GOT_11_X:
286       case fixup_Hexagon_TPREL_32_6_X:
287       case fixup_Hexagon_TPREL_16_X:
288       case fixup_Hexagon_TPREL_11_X:
289       case fixup_Hexagon_32_PCREL:
290       case fixup_Hexagon_6_PCREL_X:
291       case fixup_Hexagon_23_REG:
292         // These relocations should always have a relocation recorded
293         IsResolved = false;
294         return;
295 
296       case fixup_Hexagon_B22_PCREL:
297         //IsResolved = false;
298         break;
299 
300       case fixup_Hexagon_B13_PCREL:
301       case fixup_Hexagon_B13_PCREL_X:
302       case fixup_Hexagon_B32_PCREL_X:
303       case fixup_Hexagon_B22_PCREL_X:
304       case fixup_Hexagon_B15_PCREL:
305       case fixup_Hexagon_B15_PCREL_X:
306       case fixup_Hexagon_B9_PCREL:
307       case fixup_Hexagon_B9_PCREL_X:
308       case fixup_Hexagon_B7_PCREL:
309       case fixup_Hexagon_B7_PCREL_X:
310         if (DisableFixup)
311           IsResolved = false;
312         break;
313 
314       case FK_Data_1:
315       case FK_Data_2:
316       case FK_Data_4:
317       case FK_PCRel_4:
318       case fixup_Hexagon_32:
319         // Leave these relocations alone as they are used for EH.
320         return;
321     }
322   }
323 
324   /// getFixupKindNumBytes - The number of bytes the fixup may change.
getFixupKindNumBytes(unsigned Kind)325   static unsigned getFixupKindNumBytes(unsigned Kind) {
326     switch (Kind) {
327     default:
328         return 0;
329 
330       case FK_Data_1:
331         return 1;
332       case FK_Data_2:
333         return 2;
334       case FK_Data_4:         // this later gets mapped to R_HEX_32
335       case FK_PCRel_4:        // this later gets mapped to R_HEX_32_PCREL
336       case fixup_Hexagon_32:
337       case fixup_Hexagon_B32_PCREL_X:
338       case fixup_Hexagon_B22_PCREL:
339       case fixup_Hexagon_B22_PCREL_X:
340       case fixup_Hexagon_B15_PCREL:
341       case fixup_Hexagon_B15_PCREL_X:
342       case fixup_Hexagon_B13_PCREL:
343       case fixup_Hexagon_B13_PCREL_X:
344       case fixup_Hexagon_B9_PCREL:
345       case fixup_Hexagon_B9_PCREL_X:
346       case fixup_Hexagon_B7_PCREL:
347       case fixup_Hexagon_B7_PCREL_X:
348         return 4;
349     }
350   }
351 
352   // Make up for left shift when encoding the operand.
adjustFixupValue(MCFixupKind Kind,uint64_t Value)353   static uint64_t adjustFixupValue(MCFixupKind Kind, uint64_t Value) {
354     switch((unsigned)Kind) {
355       default:
356         break;
357 
358       case fixup_Hexagon_B7_PCREL:
359       case fixup_Hexagon_B9_PCREL:
360       case fixup_Hexagon_B13_PCREL:
361       case fixup_Hexagon_B15_PCREL:
362       case fixup_Hexagon_B22_PCREL:
363         Value >>= 2;
364         break;
365 
366       case fixup_Hexagon_B7_PCREL_X:
367       case fixup_Hexagon_B9_PCREL_X:
368       case fixup_Hexagon_B13_PCREL_X:
369       case fixup_Hexagon_B15_PCREL_X:
370       case fixup_Hexagon_B22_PCREL_X:
371         Value &= 0x3f;
372         break;
373 
374       case fixup_Hexagon_B32_PCREL_X:
375         Value >>= 6;
376         break;
377     }
378     return (Value);
379   }
380 
HandleFixupError(const int bits,const int align_bits,const int64_t FixupValue,const char * fixupStr) const381   void HandleFixupError(const int bits, const int align_bits,
382     const int64_t FixupValue, const char *fixupStr) const {
383     // Error: value 1124 out of range: -1024-1023 when resolving
384     // symbol in file xprtsock.S
385     const APInt IntMin = APInt::getSignedMinValue(bits+align_bits);
386     const APInt IntMax = APInt::getSignedMaxValue(bits+align_bits);
387     std::stringstream errStr;
388     errStr << "\nError: value " <<
389       FixupValue <<
390       " out of range: " <<
391       IntMin.getSExtValue() <<
392       "-" <<
393       IntMax.getSExtValue() <<
394       " when resolving " <<
395       fixupStr <<
396       " fixup\n";
397     llvm_unreachable(errStr.str().c_str());
398   }
399 
400   /// ApplyFixup - Apply the \arg Value for given \arg Fixup into the provided
401   /// data fragment, at the offset specified by the fixup and following the
402   /// fixup kind as appropriate.
applyFixup(const MCFixup & Fixup,char * Data,unsigned DataSize,uint64_t FixupValue,bool IsPCRel) const403   void applyFixup(const MCFixup &Fixup, char *Data, unsigned DataSize,
404                   uint64_t FixupValue, bool IsPCRel) const override {
405 
406     // When FixupValue is 0 the relocation is external and there
407     // is nothing for us to do.
408     if (!FixupValue) return;
409 
410     MCFixupKind Kind = Fixup.getKind();
411     uint64_t Value;
412     uint32_t InstMask;
413     uint32_t Reloc;
414 
415     // LLVM gives us an encoded value, we have to convert it back
416     // to a real offset before we can use it.
417     uint32_t Offset = Fixup.getOffset();
418     unsigned NumBytes = getFixupKindNumBytes(Kind);
419     assert(Offset + NumBytes <= DataSize && "Invalid fixup offset!");
420     char *InstAddr = Data + Offset;
421 
422     Value = adjustFixupValue(Kind, FixupValue);
423     if(!Value)
424       return;
425     int sValue = (int)Value;
426 
427     switch((unsigned)Kind) {
428       default:
429         return;
430 
431       case fixup_Hexagon_B7_PCREL:
432         if (!(isIntN(7, sValue)))
433           HandleFixupError(7, 2, (int64_t)FixupValue, "B7_PCREL");
434       case fixup_Hexagon_B7_PCREL_X:
435         InstMask = 0x00001f18;  // Word32_B7
436         Reloc = (((Value >> 2) & 0x1f) << 8) |    // Value 6-2 = Target 12-8
437                 ((Value & 0x3) << 3);             // Value 1-0 = Target 4-3
438         break;
439 
440       case fixup_Hexagon_B9_PCREL:
441         if (!(isIntN(9, sValue)))
442           HandleFixupError(9, 2, (int64_t)FixupValue, "B9_PCREL");
443       case fixup_Hexagon_B9_PCREL_X:
444         InstMask = 0x003000fe;  // Word32_B9
445         Reloc = (((Value >> 7) & 0x3) << 20) |    // Value 8-7 = Target 21-20
446                 ((Value & 0x7f) << 1);            // Value 6-0 = Target 7-1
447         break;
448 
449         // Since the existing branches that use this relocation cannot be
450         // extended, they should only be fixed up if the target is within range.
451       case fixup_Hexagon_B13_PCREL:
452         if (!(isIntN(13, sValue)))
453           HandleFixupError(13, 2, (int64_t)FixupValue, "B13_PCREL");
454       case fixup_Hexagon_B13_PCREL_X:
455         InstMask = 0x00202ffe;  // Word32_B13
456         Reloc = (((Value >> 12) & 0x1) << 21) |    // Value 12   = Target 21
457                 (((Value >> 11) & 0x1) << 13) |    // Value 11   = Target 13
458                 ((Value & 0x7ff) << 1);            // Value 10-0 = Target 11-1
459         break;
460 
461       case fixup_Hexagon_B15_PCREL:
462         if (!(isIntN(15, sValue)))
463           HandleFixupError(15, 2, (int64_t)FixupValue, "B15_PCREL");
464       case fixup_Hexagon_B15_PCREL_X:
465         InstMask = 0x00df20fe;  // Word32_B15
466         Reloc = (((Value >> 13) & 0x3) << 22) |    // Value 14-13 = Target 23-22
467                 (((Value >> 8) & 0x1f) << 16) |    // Value 12-8  = Target 20-16
468                 (((Value >> 7) & 0x1)  << 13) |    // Value 7     = Target 13
469                 ((Value & 0x7f) << 1);             // Value 6-0   = Target 7-1
470         break;
471 
472       case fixup_Hexagon_B22_PCREL:
473         if (!(isIntN(22, sValue)))
474           HandleFixupError(22, 2, (int64_t)FixupValue, "B22_PCREL");
475       case fixup_Hexagon_B22_PCREL_X:
476         InstMask = 0x01ff3ffe;  // Word32_B22
477         Reloc = (((Value >> 13) & 0x1ff) << 16) |  // Value 21-13 = Target 24-16
478                 ((Value & 0x1fff) << 1);           // Value 12-0  = Target 13-1
479         break;
480 
481       case fixup_Hexagon_B32_PCREL_X:
482         InstMask = 0x0fff3fff;  // Word32_X26
483         Reloc = (((Value >> 14) & 0xfff) << 16) |  // Value 25-14 = Target 27-16
484                 (Value & 0x3fff);                  // Value 13-0  = Target 13-0
485         break;
486 
487       case FK_Data_1:
488       case FK_Data_2:
489       case FK_Data_4:
490       case fixup_Hexagon_32:
491         InstMask = 0xffffffff;  // Word32
492         Reloc = Value;
493         break;
494     }
495 
496     DEBUG(dbgs() << "Name=" << getFixupKindInfo(Kind).Name << "(" <<
497           (unsigned)Kind << ")\n");
498     DEBUG(uint32_t OldData = 0;
499           for (unsigned i = 0; i < NumBytes; i++)
500             OldData |= (InstAddr[i] << (i * 8)) & (0xff << (i * 8));
501           dbgs() << "\tBValue=0x"; dbgs().write_hex(Value) <<
502             ": AValue=0x"; dbgs().write_hex(FixupValue) <<
503             ": Offset=" << Offset <<
504             ": Size=" << DataSize <<
505             ": OInst=0x"; dbgs().write_hex(OldData) <<
506             ": Reloc=0x"; dbgs().write_hex(Reloc););
507 
508     // For each byte of the fragment that the fixup touches, mask in the
509     // bits from the fixup value. The Value has been "split up" into the
510     // appropriate bitfields above.
511     for (unsigned i = 0; i < NumBytes; i++){
512       InstAddr[i] &= uint8_t(~InstMask >> (i * 8)) & 0xff; // Clear reloc bits
513       InstAddr[i] |= uint8_t(Reloc >> (i * 8)) & 0xff;     // Apply new reloc
514     }
515 
516     DEBUG(uint32_t NewData = 0;
517           for (unsigned i = 0; i < NumBytes; i++)
518             NewData |= (InstAddr[i] << (i * 8)) & (0xff << (i * 8));
519           dbgs() << ": NInst=0x"; dbgs().write_hex(NewData) << "\n";);
520   }
521 
isInstRelaxable(MCInst const & HMI) const522   bool isInstRelaxable(MCInst const &HMI) const {
523     const MCInstrDesc &MCID = HexagonMCInstrInfo::getDesc(*MCII, HMI);
524     bool Relaxable = false;
525     // Branches and loop-setup insns are handled as necessary by relaxation.
526     if (llvm::HexagonMCInstrInfo::getType(*MCII, HMI) == HexagonII::TypeJ ||
527         (llvm::HexagonMCInstrInfo::getType(*MCII, HMI) ==
528              HexagonII::TypeCOMPOUND &&
529          MCID.isBranch()) ||
530         (llvm::HexagonMCInstrInfo::getType(*MCII, HMI) == HexagonII::TypeNV &&
531          MCID.isBranch()) ||
532         (llvm::HexagonMCInstrInfo::getType(*MCII, HMI) == HexagonII::TypeCR &&
533          HMI.getOpcode() != Hexagon::C4_addipc))
534       if (HexagonMCInstrInfo::isExtendable(*MCII, HMI)) {
535         Relaxable = true;
536         MCOperand const &Operand =
537             HMI.getOperand(HexagonMCInstrInfo::getExtendableOp(*MCII, HMI));
538         if (HexagonMCInstrInfo::mustNotExtend(*Operand.getExpr()))
539           Relaxable = false;
540       }
541 
542     return Relaxable;
543   }
544 
545   /// MayNeedRelaxation - Check whether the given instruction may need
546   /// relaxation.
547   ///
548   /// \param Inst - The instruction to test.
mayNeedRelaxation(MCInst const & Inst) const549   bool mayNeedRelaxation(MCInst const &Inst) const override {
550     return true;
551   }
552 
553   /// fixupNeedsRelaxation - Target specific predicate for whether a given
554   /// fixup requires the associated instruction to be relaxed.
fixupNeedsRelaxationAdvanced(const MCFixup & Fixup,bool Resolved,uint64_t Value,const MCRelaxableFragment * DF,const MCAsmLayout & Layout) const555   bool fixupNeedsRelaxationAdvanced(const MCFixup &Fixup, bool Resolved,
556                                     uint64_t Value,
557                                     const MCRelaxableFragment *DF,
558                                     const MCAsmLayout &Layout) const override {
559     MCInst const &MCB = DF->getInst();
560     assert(HexagonMCInstrInfo::isBundle(MCB));
561 
562     *RelaxTarget = nullptr;
563     MCInst &MCI = const_cast<MCInst &>(HexagonMCInstrInfo::instruction(
564         MCB, Fixup.getOffset() / HEXAGON_INSTR_SIZE));
565     bool Relaxable = isInstRelaxable(MCI);
566     if (Relaxable == false)
567       return false;
568     // If we cannot resolve the fixup value, it requires relaxation.
569     if (!Resolved) {
570       switch ((unsigned)Fixup.getKind()) {
571       case fixup_Hexagon_B22_PCREL:
572       // GetFixupCount assumes B22 won't relax
573       // Fallthrough
574       default:
575         return false;
576         break;
577       case fixup_Hexagon_B13_PCREL:
578       case fixup_Hexagon_B15_PCREL:
579       case fixup_Hexagon_B9_PCREL:
580       case fixup_Hexagon_B7_PCREL: {
581         if (HexagonMCInstrInfo::bundleSize(MCB) < HEXAGON_PACKET_SIZE) {
582           ++relaxedCnt;
583           *RelaxTarget = &MCI;
584           setExtender(Layout.getAssembler().getContext());
585           return true;
586         } else {
587           return false;
588         }
589         break;
590       }
591       }
592     }
593 
594     MCFixupKind Kind = Fixup.getKind();
595     int64_t sValue = Value;
596     int64_t maxValue;
597 
598     switch ((unsigned)Kind) {
599     case fixup_Hexagon_B7_PCREL:
600       maxValue = 1 << 8;
601       break;
602     case fixup_Hexagon_B9_PCREL:
603       maxValue = 1 << 10;
604       break;
605     case fixup_Hexagon_B15_PCREL:
606       maxValue = 1 << 16;
607       break;
608     case fixup_Hexagon_B22_PCREL:
609       maxValue = 1 << 23;
610       break;
611     default:
612       maxValue = INT64_MAX;
613       break;
614     }
615 
616     bool isFarAway = -maxValue > sValue || sValue > maxValue - 1;
617 
618     if (isFarAway) {
619       if (HexagonMCInstrInfo::bundleSize(MCB) < HEXAGON_PACKET_SIZE) {
620         ++relaxedCnt;
621         *RelaxTarget = &MCI;
622         setExtender(Layout.getAssembler().getContext());
623         return true;
624       }
625     }
626 
627     return false;
628   }
629 
630   /// Simple predicate for targets where !Resolved implies requiring relaxation
fixupNeedsRelaxation(const MCFixup & Fixup,uint64_t Value,const MCRelaxableFragment * DF,const MCAsmLayout & Layout) const631   bool fixupNeedsRelaxation(const MCFixup &Fixup, uint64_t Value,
632                             const MCRelaxableFragment *DF,
633                             const MCAsmLayout &Layout) const override {
634     llvm_unreachable("Handled by fixupNeedsRelaxationAdvanced");
635   }
636 
relaxInstruction(const MCInst & Inst,const MCSubtargetInfo & STI,MCInst & Res) const637   void relaxInstruction(const MCInst &Inst, const MCSubtargetInfo &STI,
638                         MCInst &Res) const override {
639     assert(HexagonMCInstrInfo::isBundle(Inst) &&
640            "Hexagon relaxInstruction only works on bundles");
641 
642     Res = HexagonMCInstrInfo::createBundle();
643     // Copy the results into the bundle.
644     bool Update = false;
645     for (auto &I : HexagonMCInstrInfo::bundleInstructions(Inst)) {
646       MCInst &CrntHMI = const_cast<MCInst &>(*I.getInst());
647 
648       // if immediate extender needed, add it in
649       if (*RelaxTarget == &CrntHMI) {
650         Update = true;
651         assert((HexagonMCInstrInfo::bundleSize(Res) < HEXAGON_PACKET_SIZE) &&
652                "No room to insert extender for relaxation");
653 
654         MCInst *HMIx = takeExtender();
655         *HMIx = HexagonMCInstrInfo::deriveExtender(
656                 *MCII, CrntHMI,
657                 HexagonMCInstrInfo::getExtendableOperand(*MCII, CrntHMI));
658         Res.addOperand(MCOperand::createInst(HMIx));
659         *RelaxTarget = nullptr;
660       }
661       // now copy over the original instruction(the one we may have extended)
662       Res.addOperand(MCOperand::createInst(I.getInst()));
663     }
664     (void)Update;
665     assert(Update && "Didn't find relaxation target");
666   }
667 
writeNopData(uint64_t Count,MCObjectWriter * OW) const668   bool writeNopData(uint64_t Count,
669                     MCObjectWriter * OW) const override {
670     static const uint32_t Nopcode  = 0x7f000000, // Hard-coded NOP.
671                           ParseIn  = 0x00004000, // In packet parse-bits.
672                           ParseEnd = 0x0000c000; // End of packet parse-bits.
673 
674     while(Count % HEXAGON_INSTR_SIZE) {
675       DEBUG(dbgs() << "Alignment not a multiple of the instruction size:" <<
676           Count % HEXAGON_INSTR_SIZE << "/" << HEXAGON_INSTR_SIZE << "\n");
677       --Count;
678       OW->write8(0);
679     }
680 
681     while(Count) {
682       Count -= HEXAGON_INSTR_SIZE;
683       // Close the packet whenever a multiple of the maximum packet size remains
684       uint32_t ParseBits = (Count % (HEXAGON_PACKET_SIZE * HEXAGON_INSTR_SIZE))?
685                            ParseIn: ParseEnd;
686       OW->write32(Nopcode | ParseBits);
687     }
688     return true;
689   }
690 
finishLayout(MCAssembler const & Asm,MCAsmLayout & Layout) const691   void finishLayout(MCAssembler const &Asm,
692                     MCAsmLayout &Layout) const override {
693     for (auto I : Layout.getSectionOrder()) {
694       auto &Fragments = I->getFragmentList();
695       for (auto &J : Fragments) {
696         switch (J.getKind()) {
697         default:
698           break;
699         case MCFragment::FT_Align: {
700           auto Size = Asm.computeFragmentSize(Layout, J);
701           for (auto K = J.getIterator();
702                K != Fragments.begin() && Size >= HEXAGON_PACKET_SIZE;) {
703             --K;
704             switch (K->getKind()) {
705             default:
706               break;
707             case MCFragment::FT_Align: {
708               // Don't pad before other alignments
709               Size = 0;
710               break;
711             }
712             case MCFragment::FT_Relaxable: {
713               auto &RF = cast<MCRelaxableFragment>(*K);
714               auto &Inst = const_cast<MCInst &>(RF.getInst());
715               while (Size > 0 && HexagonMCInstrInfo::bundleSize(Inst) < 4) {
716                 MCInst *Nop = new (Asm.getContext()) MCInst;
717                 Nop->setOpcode(Hexagon::A2_nop);
718                 Inst.addOperand(MCOperand::createInst(Nop));
719                 Size -= 4;
720                 if (!HexagonMCChecker(
721                            *MCII, RF.getSubtargetInfo(), Inst, Inst,
722                            *Asm.getContext().getRegisterInfo()).check()) {
723                   Inst.erase(Inst.end() - 1);
724                   Size = 0;
725                 }
726               }
727               bool Error = HexagonMCShuffle(*MCII, RF.getSubtargetInfo(), Inst);
728               //assert(!Error);
729               (void)Error;
730               ReplaceInstruction(Asm.getEmitter(), RF, Inst);
731               Layout.invalidateFragmentsFrom(&RF);
732               Size = 0; // Only look back one instruction
733               break;
734             }
735             }
736           }
737         }
738         }
739       }
740     }
741   }
742 };
743 } // end anonymous namespace
744 
745 namespace llvm {
createHexagonAsmBackend(Target const & T,MCRegisterInfo const &,const Triple & TT,StringRef CPU)746 MCAsmBackend *createHexagonAsmBackend(Target const &T,
747                                       MCRegisterInfo const & /*MRI*/,
748                                       const Triple &TT, StringRef CPU) {
749   uint8_t OSABI = MCELFObjectTargetWriter::getOSABI(TT.getOS());
750   return new HexagonAsmBackend(T, OSABI, CPU);
751 }
752 }
753