1 //===-- PPCMCTargetDesc.cpp - PowerPC Target Descriptions -----------------===//
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 provides PowerPC specific target descriptions.
10 //
11 //===----------------------------------------------------------------------===//
12 
13 #include "MCTargetDesc/PPCMCTargetDesc.h"
14 #include "MCTargetDesc/PPCInstPrinter.h"
15 #include "MCTargetDesc/PPCMCAsmInfo.h"
16 #include "PPCELFStreamer.h"
17 #include "PPCTargetStreamer.h"
18 #include "PPCXCOFFStreamer.h"
19 #include "TargetInfo/PowerPCTargetInfo.h"
20 #include "llvm/ADT/SmallPtrSet.h"
21 #include "llvm/ADT/StringRef.h"
22 #include "llvm/ADT/Triple.h"
23 #include "llvm/BinaryFormat/ELF.h"
24 #include "llvm/MC/MCAsmBackend.h"
25 #include "llvm/MC/MCAssembler.h"
26 #include "llvm/MC/MCCodeEmitter.h"
27 #include "llvm/MC/MCContext.h"
28 #include "llvm/MC/MCDwarf.h"
29 #include "llvm/MC/MCELFStreamer.h"
30 #include "llvm/MC/MCExpr.h"
31 #include "llvm/MC/MCInstrAnalysis.h"
32 #include "llvm/MC/MCInstrInfo.h"
33 #include "llvm/MC/MCObjectWriter.h"
34 #include "llvm/MC/MCRegisterInfo.h"
35 #include "llvm/MC/MCSectionXCOFF.h"
36 #include "llvm/MC/MCStreamer.h"
37 #include "llvm/MC/MCSubtargetInfo.h"
38 #include "llvm/MC/MCSymbol.h"
39 #include "llvm/MC/MCSymbolELF.h"
40 #include "llvm/MC/MCSymbolXCOFF.h"
41 #include "llvm/MC/TargetRegistry.h"
42 #include "llvm/Support/Casting.h"
43 #include "llvm/Support/CodeGen.h"
44 #include "llvm/Support/ErrorHandling.h"
45 #include "llvm/Support/FormattedStream.h"
46 #include "llvm/Support/raw_ostream.h"
47 
48 using namespace llvm;
49 
50 #define GET_INSTRINFO_MC_DESC
51 #define ENABLE_INSTR_PREDICATE_VERIFIER
52 #include "PPCGenInstrInfo.inc"
53 
54 #define GET_SUBTARGETINFO_MC_DESC
55 #include "PPCGenSubtargetInfo.inc"
56 
57 #define GET_REGINFO_MC_DESC
58 #include "PPCGenRegisterInfo.inc"
59 
60 PPCTargetStreamer::PPCTargetStreamer(MCStreamer &S) : MCTargetStreamer(S) {}
61 
62 // Pin the vtable to this file.
63 PPCTargetStreamer::~PPCTargetStreamer() = default;
64 
65 static MCInstrInfo *createPPCMCInstrInfo() {
66   MCInstrInfo *X = new MCInstrInfo();
67   InitPPCMCInstrInfo(X);
68   return X;
69 }
70 
71 static MCRegisterInfo *createPPCMCRegisterInfo(const Triple &TT) {
72   bool isPPC64 =
73       (TT.getArch() == Triple::ppc64 || TT.getArch() == Triple::ppc64le);
74   unsigned Flavour = isPPC64 ? 0 : 1;
75   unsigned RA = isPPC64 ? PPC::LR8 : PPC::LR;
76 
77   MCRegisterInfo *X = new MCRegisterInfo();
78   InitPPCMCRegisterInfo(X, RA, Flavour, Flavour);
79   return X;
80 }
81 
82 static MCSubtargetInfo *createPPCMCSubtargetInfo(const Triple &TT,
83                                                  StringRef CPU, StringRef FS) {
84   // Set some default feature to MC layer.
85   std::string FullFS = std::string(FS);
86 
87   if (TT.isOSAIX()) {
88     if (!FullFS.empty())
89       FullFS = "+aix," + FullFS;
90     else
91       FullFS = "+aix";
92   }
93 
94   return createPPCMCSubtargetInfoImpl(TT, CPU, /*TuneCPU*/ CPU, FullFS);
95 }
96 
97 static MCAsmInfo *createPPCMCAsmInfo(const MCRegisterInfo &MRI,
98                                      const Triple &TheTriple,
99                                      const MCTargetOptions &Options) {
100   bool isPPC64 = (TheTriple.getArch() == Triple::ppc64 ||
101                   TheTriple.getArch() == Triple::ppc64le);
102 
103   MCAsmInfo *MAI;
104   if (TheTriple.isOSBinFormatXCOFF())
105     MAI = new PPCXCOFFMCAsmInfo(isPPC64, TheTriple);
106   else
107     MAI = new PPCELFMCAsmInfo(isPPC64, TheTriple);
108 
109   // Initial state of the frame pointer is R1.
110   unsigned Reg = isPPC64 ? PPC::X1 : PPC::R1;
111   MCCFIInstruction Inst =
112       MCCFIInstruction::cfiDefCfa(nullptr, MRI.getDwarfRegNum(Reg, true), 0);
113   MAI->addInitialFrameState(Inst);
114 
115   return MAI;
116 }
117 
118 static MCStreamer *
119 createPPCELFStreamer(const Triple &T, MCContext &Context,
120                      std::unique_ptr<MCAsmBackend> &&MAB,
121                      std::unique_ptr<MCObjectWriter> &&OW,
122                      std::unique_ptr<MCCodeEmitter> &&Emitter, bool RelaxAll) {
123   return createPPCELFStreamer(Context, std::move(MAB), std::move(OW),
124                               std::move(Emitter));
125 }
126 
127 static MCStreamer *createPPCXCOFFStreamer(
128     const Triple &T, MCContext &Context, std::unique_ptr<MCAsmBackend> &&MAB,
129     std::unique_ptr<MCObjectWriter> &&OW,
130     std::unique_ptr<MCCodeEmitter> &&Emitter, bool RelaxAll) {
131   return createPPCXCOFFStreamer(Context, std::move(MAB), std::move(OW),
132                                 std::move(Emitter));
133 }
134 
135 namespace {
136 
137 class PPCTargetAsmStreamer : public PPCTargetStreamer {
138   formatted_raw_ostream &OS;
139 
140 public:
141   PPCTargetAsmStreamer(MCStreamer &S, formatted_raw_ostream &OS)
142       : PPCTargetStreamer(S), OS(OS) {}
143 
144   void emitTCEntry(const MCSymbol &S,
145                    MCSymbolRefExpr::VariantKind Kind) override {
146     if (const MCSymbolXCOFF *XSym = dyn_cast<MCSymbolXCOFF>(&S)) {
147       MCSymbolXCOFF *TCSym =
148           cast<MCSectionXCOFF>(Streamer.getCurrentSectionOnly())
149               ->getQualNameSymbol();
150       // If the variant kind is VK_PPC_AIX_TLSGDM the entry represents the
151       // region handle for the symbol, we add the relocation specifier @m.
152       // If the variant kind is VK_PPC_AIX_TLSGD the entry represents the
153       // variable offset for the symbol, we add the relocation specifier @gd.
154       if (Kind == MCSymbolRefExpr::VariantKind::VK_PPC_AIX_TLSGD ||
155           Kind == MCSymbolRefExpr::VariantKind::VK_PPC_AIX_TLSGDM)
156         OS << "\t.tc " << TCSym->getName() << "," << XSym->getName() << "@"
157            << MCSymbolRefExpr::getVariantKindName(Kind) << '\n';
158       else
159         OS << "\t.tc " << TCSym->getName() << "," << XSym->getName() << '\n';
160 
161       if (TCSym->hasRename())
162         Streamer.emitXCOFFRenameDirective(TCSym, TCSym->getSymbolTableName());
163       return;
164     }
165 
166     OS << "\t.tc " << S.getName() << "[TC]," << S.getName() << '\n';
167   }
168 
169   void emitMachine(StringRef CPU) override {
170     OS << "\t.machine " << CPU << '\n';
171   }
172 
173   void emitAbiVersion(int AbiVersion) override {
174     OS << "\t.abiversion " << AbiVersion << '\n';
175   }
176 
177   void emitLocalEntry(MCSymbolELF *S, const MCExpr *LocalOffset) override {
178     const MCAsmInfo *MAI = Streamer.getContext().getAsmInfo();
179 
180     OS << "\t.localentry\t";
181     S->print(OS, MAI);
182     OS << ", ";
183     LocalOffset->print(OS, MAI);
184     OS << '\n';
185   }
186 };
187 
188 class PPCTargetELFStreamer : public PPCTargetStreamer {
189 public:
190   PPCTargetELFStreamer(MCStreamer &S) : PPCTargetStreamer(S) {}
191 
192   MCELFStreamer &getStreamer() {
193     return static_cast<MCELFStreamer &>(Streamer);
194   }
195 
196   void emitTCEntry(const MCSymbol &S,
197                    MCSymbolRefExpr::VariantKind Kind) override {
198     // Creates a R_PPC64_TOC relocation
199     Streamer.emitValueToAlignment(8);
200     Streamer.emitSymbolValue(&S, 8);
201   }
202 
203   void emitMachine(StringRef CPU) override {
204     // FIXME: Is there anything to do in here or does this directive only
205     // limit the parser?
206   }
207 
208   void emitAbiVersion(int AbiVersion) override {
209     MCAssembler &MCA = getStreamer().getAssembler();
210     unsigned Flags = MCA.getELFHeaderEFlags();
211     Flags &= ~ELF::EF_PPC64_ABI;
212     Flags |= (AbiVersion & ELF::EF_PPC64_ABI);
213     MCA.setELFHeaderEFlags(Flags);
214   }
215 
216   void emitLocalEntry(MCSymbolELF *S, const MCExpr *LocalOffset) override {
217     MCAssembler &MCA = getStreamer().getAssembler();
218 
219     // encodePPC64LocalEntryOffset will report an error if it cannot
220     // encode LocalOffset.
221     unsigned Encoded = encodePPC64LocalEntryOffset(LocalOffset);
222 
223     unsigned Other = S->getOther();
224     Other &= ~ELF::STO_PPC64_LOCAL_MASK;
225     Other |= Encoded;
226     S->setOther(Other);
227 
228     // For GAS compatibility, unless we already saw a .abiversion directive,
229     // set e_flags to indicate ELFv2 ABI.
230     unsigned Flags = MCA.getELFHeaderEFlags();
231     if ((Flags & ELF::EF_PPC64_ABI) == 0)
232       MCA.setELFHeaderEFlags(Flags | 2);
233   }
234 
235   void emitAssignment(MCSymbol *S, const MCExpr *Value) override {
236     auto *Symbol = cast<MCSymbolELF>(S);
237 
238     // When encoding an assignment to set symbol A to symbol B, also copy
239     // the st_other bits encoding the local entry point offset.
240     if (copyLocalEntry(Symbol, Value))
241       UpdateOther.insert(Symbol);
242     else
243       UpdateOther.erase(Symbol);
244   }
245 
246   void finish() override {
247     for (auto *Sym : UpdateOther)
248       if (Sym->isVariable())
249         copyLocalEntry(Sym, Sym->getVariableValue());
250 
251     // Clear the set of symbols that needs to be updated so the streamer can
252     // be reused without issues.
253     UpdateOther.clear();
254   }
255 
256 private:
257   SmallPtrSet<MCSymbolELF *, 32> UpdateOther;
258 
259   bool copyLocalEntry(MCSymbolELF *D, const MCExpr *S) {
260     auto *Ref = dyn_cast<const MCSymbolRefExpr>(S);
261     if (!Ref)
262       return false;
263     const auto &RhsSym = cast<MCSymbolELF>(Ref->getSymbol());
264     unsigned Other = D->getOther();
265     Other &= ~ELF::STO_PPC64_LOCAL_MASK;
266     Other |= RhsSym.getOther() & ELF::STO_PPC64_LOCAL_MASK;
267     D->setOther(Other);
268     return true;
269   }
270 
271   unsigned encodePPC64LocalEntryOffset(const MCExpr *LocalOffset) {
272     MCAssembler &MCA = getStreamer().getAssembler();
273     int64_t Offset;
274     if (!LocalOffset->evaluateAsAbsolute(Offset, MCA))
275       MCA.getContext().reportError(LocalOffset->getLoc(),
276                                    ".localentry expression must be absolute");
277 
278     switch (Offset) {
279     default:
280       MCA.getContext().reportError(
281           LocalOffset->getLoc(), ".localentry expression must be a power of 2");
282       return 0;
283     case 0:
284       return 0;
285     case 1:
286       return 1 << ELF::STO_PPC64_LOCAL_BIT;
287     case 4:
288     case 8:
289     case 16:
290     case 32:
291     case 64:
292       return (int)Log2(Offset) << (int)ELF::STO_PPC64_LOCAL_BIT;
293     }
294   }
295 };
296 
297 class PPCTargetMachOStreamer : public PPCTargetStreamer {
298 public:
299   PPCTargetMachOStreamer(MCStreamer &S) : PPCTargetStreamer(S) {}
300 
301   void emitTCEntry(const MCSymbol &S,
302                    MCSymbolRefExpr::VariantKind Kind) override {
303     llvm_unreachable("Unknown pseudo-op: .tc");
304   }
305 
306   void emitMachine(StringRef CPU) override {
307     // FIXME: We should update the CPUType, CPUSubType in the Object file if
308     // the new values are different from the defaults.
309   }
310 
311   void emitAbiVersion(int AbiVersion) override {
312     llvm_unreachable("Unknown pseudo-op: .abiversion");
313   }
314 
315   void emitLocalEntry(MCSymbolELF *S, const MCExpr *LocalOffset) override {
316     llvm_unreachable("Unknown pseudo-op: .localentry");
317   }
318 };
319 
320 class PPCTargetXCOFFStreamer : public PPCTargetStreamer {
321 public:
322   PPCTargetXCOFFStreamer(MCStreamer &S) : PPCTargetStreamer(S) {}
323 
324   void emitTCEntry(const MCSymbol &S,
325                    MCSymbolRefExpr::VariantKind Kind) override {
326     const MCAsmInfo *MAI = Streamer.getContext().getAsmInfo();
327     const unsigned PointerSize = MAI->getCodePointerSize();
328     Streamer.emitValueToAlignment(PointerSize);
329     Streamer.emitValue(MCSymbolRefExpr::create(&S, Kind, Streamer.getContext()),
330                        PointerSize);
331   }
332 
333   void emitMachine(StringRef CPU) override {
334     llvm_unreachable("Machine pseudo-ops are invalid for XCOFF.");
335   }
336 
337   void emitAbiVersion(int AbiVersion) override {
338     llvm_unreachable("ABI-version pseudo-ops are invalid for XCOFF.");
339   }
340 
341   void emitLocalEntry(MCSymbolELF *S, const MCExpr *LocalOffset) override {
342     llvm_unreachable("Local-entry pseudo-ops are invalid for XCOFF.");
343   }
344 };
345 
346 } // end anonymous namespace
347 
348 static MCTargetStreamer *createAsmTargetStreamer(MCStreamer &S,
349                                                  formatted_raw_ostream &OS,
350                                                  MCInstPrinter *InstPrint,
351                                                  bool isVerboseAsm) {
352   return new PPCTargetAsmStreamer(S, OS);
353 }
354 
355 static MCTargetStreamer *
356 createObjectTargetStreamer(MCStreamer &S, const MCSubtargetInfo &STI) {
357   const Triple &TT = STI.getTargetTriple();
358   if (TT.isOSBinFormatELF())
359     return new PPCTargetELFStreamer(S);
360   if (TT.isOSBinFormatXCOFF())
361     return new PPCTargetXCOFFStreamer(S);
362   return new PPCTargetMachOStreamer(S);
363 }
364 
365 static MCInstPrinter *createPPCMCInstPrinter(const Triple &T,
366                                              unsigned SyntaxVariant,
367                                              const MCAsmInfo &MAI,
368                                              const MCInstrInfo &MII,
369                                              const MCRegisterInfo &MRI) {
370   return new PPCInstPrinter(MAI, MII, MRI, T);
371 }
372 
373 namespace {
374 
375 class PPCMCInstrAnalysis : public MCInstrAnalysis {
376 public:
377   explicit PPCMCInstrAnalysis(const MCInstrInfo *Info)
378       : MCInstrAnalysis(Info) {}
379 
380   bool evaluateBranch(const MCInst &Inst, uint64_t Addr, uint64_t Size,
381                       uint64_t &Target) const override {
382     unsigned NumOps = Inst.getNumOperands();
383     if (NumOps == 0 ||
384         Info->get(Inst.getOpcode()).OpInfo[NumOps - 1].OperandType !=
385             MCOI::OPERAND_PCREL)
386       return false;
387     Target = Addr + Inst.getOperand(NumOps - 1).getImm() * Size;
388     return true;
389   }
390 };
391 
392 } // end anonymous namespace
393 
394 static MCInstrAnalysis *createPPCMCInstrAnalysis(const MCInstrInfo *Info) {
395   return new PPCMCInstrAnalysis(Info);
396 }
397 
398 extern "C" LLVM_EXTERNAL_VISIBILITY void LLVMInitializePowerPCTargetMC() {
399   for (Target *T : {&getThePPC32Target(), &getThePPC32LETarget(),
400                     &getThePPC64Target(), &getThePPC64LETarget()}) {
401     // Register the MC asm info.
402     RegisterMCAsmInfoFn C(*T, createPPCMCAsmInfo);
403 
404     // Register the MC instruction info.
405     TargetRegistry::RegisterMCInstrInfo(*T, createPPCMCInstrInfo);
406 
407     // Register the MC register info.
408     TargetRegistry::RegisterMCRegInfo(*T, createPPCMCRegisterInfo);
409 
410     // Register the MC subtarget info.
411     TargetRegistry::RegisterMCSubtargetInfo(*T, createPPCMCSubtargetInfo);
412 
413     // Register the MC instruction analyzer.
414     TargetRegistry::RegisterMCInstrAnalysis(*T, createPPCMCInstrAnalysis);
415 
416     // Register the MC Code Emitter
417     TargetRegistry::RegisterMCCodeEmitter(*T, createPPCMCCodeEmitter);
418 
419     // Register the asm backend.
420     TargetRegistry::RegisterMCAsmBackend(*T, createPPCAsmBackend);
421 
422     // Register the elf streamer.
423     TargetRegistry::RegisterELFStreamer(*T, createPPCELFStreamer);
424 
425     // Register the XCOFF streamer.
426     TargetRegistry::RegisterXCOFFStreamer(*T, createPPCXCOFFStreamer);
427 
428     // Register the object target streamer.
429     TargetRegistry::RegisterObjectTargetStreamer(*T,
430                                                  createObjectTargetStreamer);
431 
432     // Register the asm target streamer.
433     TargetRegistry::RegisterAsmTargetStreamer(*T, createAsmTargetStreamer);
434 
435     // Register the MCInstPrinter.
436     TargetRegistry::RegisterMCInstPrinter(*T, createPPCMCInstPrinter);
437   }
438 }
439