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 "PPCTargetStreamer.h"
17 #include "TargetInfo/PowerPCTargetInfo.h"
18 #include "llvm/ADT/SmallPtrSet.h"
19 #include "llvm/ADT/StringRef.h"
20 #include "llvm/ADT/Triple.h"
21 #include "llvm/BinaryFormat/ELF.h"
22 #include "llvm/MC/MCAssembler.h"
23 #include "llvm/MC/MCContext.h"
24 #include "llvm/MC/MCDwarf.h"
25 #include "llvm/MC/MCELFStreamer.h"
26 #include "llvm/MC/MCExpr.h"
27 #include "llvm/MC/MCInstrInfo.h"
28 #include "llvm/MC/MCRegisterInfo.h"
29 #include "llvm/MC/MCStreamer.h"
30 #include "llvm/MC/MCSubtargetInfo.h"
31 #include "llvm/MC/MCSymbol.h"
32 #include "llvm/MC/MCSymbolELF.h"
33 #include "llvm/MC/MCSymbolXCOFF.h"
34 #include "llvm/Support/Casting.h"
35 #include "llvm/Support/CodeGen.h"
36 #include "llvm/Support/ErrorHandling.h"
37 #include "llvm/Support/FormattedStream.h"
38 #include "llvm/Support/TargetRegistry.h"
39 #include "llvm/Support/raw_ostream.h"
40 
41 using namespace llvm;
42 
43 #define GET_INSTRINFO_MC_DESC
44 #include "PPCGenInstrInfo.inc"
45 
46 #define GET_SUBTARGETINFO_MC_DESC
47 #include "PPCGenSubtargetInfo.inc"
48 
49 #define GET_REGINFO_MC_DESC
50 #include "PPCGenRegisterInfo.inc"
51 
52 PPCTargetStreamer::PPCTargetStreamer(MCStreamer &S) : MCTargetStreamer(S) {}
53 
54 // Pin the vtable to this file.
55 PPCTargetStreamer::~PPCTargetStreamer() = default;
56 
57 static MCInstrInfo *createPPCMCInstrInfo() {
58   MCInstrInfo *X = new MCInstrInfo();
59   InitPPCMCInstrInfo(X);
60   return X;
61 }
62 
63 static MCRegisterInfo *createPPCMCRegisterInfo(const Triple &TT) {
64   bool isPPC64 =
65       (TT.getArch() == Triple::ppc64 || TT.getArch() == Triple::ppc64le);
66   unsigned Flavour = isPPC64 ? 0 : 1;
67   unsigned RA = isPPC64 ? PPC::LR8 : PPC::LR;
68 
69   MCRegisterInfo *X = new MCRegisterInfo();
70   InitPPCMCRegisterInfo(X, RA, Flavour, Flavour);
71   return X;
72 }
73 
74 static MCSubtargetInfo *createPPCMCSubtargetInfo(const Triple &TT,
75                                                  StringRef CPU, StringRef FS) {
76   return createPPCMCSubtargetInfoImpl(TT, CPU, FS);
77 }
78 
79 static MCAsmInfo *createPPCMCAsmInfo(const MCRegisterInfo &MRI,
80                                      const Triple &TheTriple,
81                                      const MCTargetOptions &Options) {
82   bool isPPC64 = (TheTriple.getArch() == Triple::ppc64 ||
83                   TheTriple.getArch() == Triple::ppc64le);
84 
85   MCAsmInfo *MAI;
86   if (TheTriple.isOSDarwin())
87     MAI = new PPCMCAsmInfoDarwin(isPPC64, TheTriple);
88   else if (TheTriple.isOSBinFormatXCOFF())
89     MAI = new PPCXCOFFMCAsmInfo(isPPC64, TheTriple);
90   else
91     MAI = new PPCELFMCAsmInfo(isPPC64, TheTriple);
92 
93   // Initial state of the frame pointer is R1.
94   unsigned Reg = isPPC64 ? PPC::X1 : PPC::R1;
95   MCCFIInstruction Inst =
96       MCCFIInstruction::createDefCfa(nullptr, MRI.getDwarfRegNum(Reg, true), 0);
97   MAI->addInitialFrameState(Inst);
98 
99   return MAI;
100 }
101 
102 namespace {
103 
104 class PPCTargetAsmStreamer : public PPCTargetStreamer {
105   formatted_raw_ostream &OS;
106 
107 public:
108   PPCTargetAsmStreamer(MCStreamer &S, formatted_raw_ostream &OS)
109       : PPCTargetStreamer(S), OS(OS) {}
110 
111   void emitTCEntry(const MCSymbol &S) override {
112     const MCAsmInfo *MAI = Streamer.getContext().getAsmInfo();
113     OS << "\t.tc ";
114     OS << (MAI->getSymbolsHaveSMC()
115                ? cast<MCSymbolXCOFF>(S).getUnqualifiedName()
116                : S.getName());
117     OS << "[TC],";
118     OS << S.getName();
119     OS << '\n';
120   }
121 
122   void emitMachine(StringRef CPU) override {
123     OS << "\t.machine " << CPU << '\n';
124   }
125 
126   void emitAbiVersion(int AbiVersion) override {
127     OS << "\t.abiversion " << AbiVersion << '\n';
128   }
129 
130   void emitLocalEntry(MCSymbolELF *S, const MCExpr *LocalOffset) override {
131     const MCAsmInfo *MAI = Streamer.getContext().getAsmInfo();
132 
133     OS << "\t.localentry\t";
134     S->print(OS, MAI);
135     OS << ", ";
136     LocalOffset->print(OS, MAI);
137     OS << '\n';
138   }
139 };
140 
141 class PPCTargetELFStreamer : public PPCTargetStreamer {
142 public:
143   PPCTargetELFStreamer(MCStreamer &S) : PPCTargetStreamer(S) {}
144 
145   MCELFStreamer &getStreamer() {
146     return static_cast<MCELFStreamer &>(Streamer);
147   }
148 
149   void emitTCEntry(const MCSymbol &S) override {
150     // Creates a R_PPC64_TOC relocation
151     Streamer.EmitValueToAlignment(8);
152     Streamer.EmitSymbolValue(&S, 8);
153   }
154 
155   void emitMachine(StringRef CPU) override {
156     // FIXME: Is there anything to do in here or does this directive only
157     // limit the parser?
158   }
159 
160   void emitAbiVersion(int AbiVersion) override {
161     MCAssembler &MCA = getStreamer().getAssembler();
162     unsigned Flags = MCA.getELFHeaderEFlags();
163     Flags &= ~ELF::EF_PPC64_ABI;
164     Flags |= (AbiVersion & ELF::EF_PPC64_ABI);
165     MCA.setELFHeaderEFlags(Flags);
166   }
167 
168   void emitLocalEntry(MCSymbolELF *S, const MCExpr *LocalOffset) override {
169     MCAssembler &MCA = getStreamer().getAssembler();
170 
171     int64_t Res;
172     if (!LocalOffset->evaluateAsAbsolute(Res, MCA))
173       report_fatal_error(".localentry expression must be absolute.");
174 
175     unsigned Encoded = ELF::encodePPC64LocalEntryOffset(Res);
176     if (Res != ELF::decodePPC64LocalEntryOffset(Encoded))
177       report_fatal_error(".localentry expression cannot be encoded.");
178 
179     unsigned Other = S->getOther();
180     Other &= ~ELF::STO_PPC64_LOCAL_MASK;
181     Other |= Encoded;
182     S->setOther(Other);
183 
184     // For GAS compatibility, unless we already saw a .abiversion directive,
185     // set e_flags to indicate ELFv2 ABI.
186     unsigned Flags = MCA.getELFHeaderEFlags();
187     if ((Flags & ELF::EF_PPC64_ABI) == 0)
188       MCA.setELFHeaderEFlags(Flags | 2);
189   }
190 
191   void emitAssignment(MCSymbol *S, const MCExpr *Value) override {
192     auto *Symbol = cast<MCSymbolELF>(S);
193 
194     // When encoding an assignment to set symbol A to symbol B, also copy
195     // the st_other bits encoding the local entry point offset.
196     if (copyLocalEntry(Symbol, Value))
197       UpdateOther.insert(Symbol);
198     else
199       UpdateOther.erase(Symbol);
200   }
201 
202   void finish() override {
203     for (auto *Sym : UpdateOther)
204       if (Sym->isVariable())
205         copyLocalEntry(Sym, Sym->getVariableValue());
206   }
207 
208 private:
209   SmallPtrSet<MCSymbolELF *, 32> UpdateOther;
210 
211   bool copyLocalEntry(MCSymbolELF *D, const MCExpr *S) {
212     auto *Ref = dyn_cast<const MCSymbolRefExpr>(S);
213     if (!Ref)
214       return false;
215     const auto &RhsSym = cast<MCSymbolELF>(Ref->getSymbol());
216     unsigned Other = D->getOther();
217     Other &= ~ELF::STO_PPC64_LOCAL_MASK;
218     Other |= RhsSym.getOther() & ELF::STO_PPC64_LOCAL_MASK;
219     D->setOther(Other);
220     return true;
221   }
222 };
223 
224 class PPCTargetMachOStreamer : public PPCTargetStreamer {
225 public:
226   PPCTargetMachOStreamer(MCStreamer &S) : PPCTargetStreamer(S) {}
227 
228   void emitTCEntry(const MCSymbol &S) override {
229     llvm_unreachable("Unknown pseudo-op: .tc");
230   }
231 
232   void emitMachine(StringRef CPU) override {
233     // FIXME: We should update the CPUType, CPUSubType in the Object file if
234     // the new values are different from the defaults.
235   }
236 
237   void emitAbiVersion(int AbiVersion) override {
238     llvm_unreachable("Unknown pseudo-op: .abiversion");
239   }
240 
241   void emitLocalEntry(MCSymbolELF *S, const MCExpr *LocalOffset) override {
242     llvm_unreachable("Unknown pseudo-op: .localentry");
243   }
244 };
245 
246 class PPCTargetXCOFFStreamer : public PPCTargetStreamer {
247 public:
248   PPCTargetXCOFFStreamer(MCStreamer &S) : PPCTargetStreamer(S) {}
249 
250   void emitTCEntry(const MCSymbol &S) override {
251     const MCAsmInfo *MAI = Streamer.getContext().getAsmInfo();
252     const unsigned PointerSize = MAI->getCodePointerSize();
253     Streamer.EmitValueToAlignment(PointerSize);
254     Streamer.EmitSymbolValue(&S, PointerSize);
255   }
256 
257   void emitMachine(StringRef CPU) override {
258     llvm_unreachable("Machine pseudo-ops are invalid for XCOFF.");
259   }
260 
261   void emitAbiVersion(int AbiVersion) override {
262     llvm_unreachable("ABI-version pseudo-ops are invalid for XCOFF.");
263   }
264 
265   void emitLocalEntry(MCSymbolELF *S, const MCExpr *LocalOffset) override {
266     llvm_unreachable("Local-entry pseudo-ops are invalid for XCOFF.");
267   }
268 };
269 
270 } // end anonymous namespace
271 
272 static MCTargetStreamer *createAsmTargetStreamer(MCStreamer &S,
273                                                  formatted_raw_ostream &OS,
274                                                  MCInstPrinter *InstPrint,
275                                                  bool isVerboseAsm) {
276   return new PPCTargetAsmStreamer(S, OS);
277 }
278 
279 static MCTargetStreamer *
280 createObjectTargetStreamer(MCStreamer &S, const MCSubtargetInfo &STI) {
281   const Triple &TT = STI.getTargetTriple();
282   if (TT.isOSBinFormatELF())
283     return new PPCTargetELFStreamer(S);
284   if (TT.isOSBinFormatXCOFF())
285     return new PPCTargetXCOFFStreamer(S);
286   return new PPCTargetMachOStreamer(S);
287 }
288 
289 static MCInstPrinter *createPPCMCInstPrinter(const Triple &T,
290                                              unsigned SyntaxVariant,
291                                              const MCAsmInfo &MAI,
292                                              const MCInstrInfo &MII,
293                                              const MCRegisterInfo &MRI) {
294   return new PPCInstPrinter(MAI, MII, MRI, T);
295 }
296 
297 extern "C" void LLVMInitializePowerPCTargetMC() {
298   for (Target *T :
299        {&getThePPC32Target(), &getThePPC64Target(), &getThePPC64LETarget()}) {
300     // Register the MC asm info.
301     RegisterMCAsmInfoFn C(*T, createPPCMCAsmInfo);
302 
303     // Register the MC instruction info.
304     TargetRegistry::RegisterMCInstrInfo(*T, createPPCMCInstrInfo);
305 
306     // Register the MC register info.
307     TargetRegistry::RegisterMCRegInfo(*T, createPPCMCRegisterInfo);
308 
309     // Register the MC subtarget info.
310     TargetRegistry::RegisterMCSubtargetInfo(*T, createPPCMCSubtargetInfo);
311 
312     // Register the MC Code Emitter
313     TargetRegistry::RegisterMCCodeEmitter(*T, createPPCMCCodeEmitter);
314 
315     // Register the asm backend.
316     TargetRegistry::RegisterMCAsmBackend(*T, createPPCAsmBackend);
317 
318     // Register the object target streamer.
319     TargetRegistry::RegisterObjectTargetStreamer(*T,
320                                                  createObjectTargetStreamer);
321 
322     // Register the asm target streamer.
323     TargetRegistry::RegisterAsmTargetStreamer(*T, createAsmTargetStreamer);
324 
325     // Register the MCInstPrinter.
326     TargetRegistry::RegisterMCInstPrinter(*T, createPPCMCInstPrinter);
327   }
328 }
329