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       copyLocalEntry(Sym, Sym->getVariableValue());
205   }
206 
207 private:
208   SmallPtrSet<MCSymbolELF *, 32> UpdateOther;
209 
210   bool copyLocalEntry(MCSymbolELF *D, const MCExpr *S) {
211     auto *Ref = dyn_cast<const MCSymbolRefExpr>(S);
212     if (!Ref)
213       return false;
214     const auto &RhsSym = cast<MCSymbolELF>(Ref->getSymbol());
215     unsigned Other = D->getOther();
216     Other &= ~ELF::STO_PPC64_LOCAL_MASK;
217     Other |= RhsSym.getOther() & ELF::STO_PPC64_LOCAL_MASK;
218     D->setOther(Other);
219     return true;
220   }
221 };
222 
223 class PPCTargetMachOStreamer : public PPCTargetStreamer {
224 public:
225   PPCTargetMachOStreamer(MCStreamer &S) : PPCTargetStreamer(S) {}
226 
227   void emitTCEntry(const MCSymbol &S) override {
228     llvm_unreachable("Unknown pseudo-op: .tc");
229   }
230 
231   void emitMachine(StringRef CPU) override {
232     // FIXME: We should update the CPUType, CPUSubType in the Object file if
233     // the new values are different from the defaults.
234   }
235 
236   void emitAbiVersion(int AbiVersion) override {
237     llvm_unreachable("Unknown pseudo-op: .abiversion");
238   }
239 
240   void emitLocalEntry(MCSymbolELF *S, const MCExpr *LocalOffset) override {
241     llvm_unreachable("Unknown pseudo-op: .localentry");
242   }
243 };
244 
245 class PPCTargetXCOFFStreamer : public PPCTargetStreamer {
246 public:
247   PPCTargetXCOFFStreamer(MCStreamer &S) : PPCTargetStreamer(S) {}
248 
249   void emitTCEntry(const MCSymbol &S) override {
250     const MCAsmInfo *MAI = Streamer.getContext().getAsmInfo();
251     const unsigned PointerSize = MAI->getCodePointerSize();
252     Streamer.EmitValueToAlignment(PointerSize);
253     Streamer.EmitSymbolValue(&S, PointerSize);
254   }
255 
256   void emitMachine(StringRef CPU) override {
257     llvm_unreachable("Machine pseudo-ops are invalid for XCOFF.");
258   }
259 
260   void emitAbiVersion(int AbiVersion) override {
261     llvm_unreachable("ABI-version pseudo-ops are invalid for XCOFF.");
262   }
263 
264   void emitLocalEntry(MCSymbolELF *S, const MCExpr *LocalOffset) override {
265     llvm_unreachable("Local-entry pseudo-ops are invalid for XCOFF.");
266   }
267 };
268 
269 } // end anonymous namespace
270 
271 static MCTargetStreamer *createAsmTargetStreamer(MCStreamer &S,
272                                                  formatted_raw_ostream &OS,
273                                                  MCInstPrinter *InstPrint,
274                                                  bool isVerboseAsm) {
275   return new PPCTargetAsmStreamer(S, OS);
276 }
277 
278 static MCTargetStreamer *
279 createObjectTargetStreamer(MCStreamer &S, const MCSubtargetInfo &STI) {
280   const Triple &TT = STI.getTargetTriple();
281   if (TT.isOSBinFormatELF())
282     return new PPCTargetELFStreamer(S);
283   if (TT.isOSBinFormatXCOFF())
284     return new PPCTargetXCOFFStreamer(S);
285   return new PPCTargetMachOStreamer(S);
286 }
287 
288 static MCInstPrinter *createPPCMCInstPrinter(const Triple &T,
289                                              unsigned SyntaxVariant,
290                                              const MCAsmInfo &MAI,
291                                              const MCInstrInfo &MII,
292                                              const MCRegisterInfo &MRI) {
293   return new PPCInstPrinter(MAI, MII, MRI, T);
294 }
295 
296 extern "C" void LLVMInitializePowerPCTargetMC() {
297   for (Target *T :
298        {&getThePPC32Target(), &getThePPC64Target(), &getThePPC64LETarget()}) {
299     // Register the MC asm info.
300     RegisterMCAsmInfoFn C(*T, createPPCMCAsmInfo);
301 
302     // Register the MC instruction info.
303     TargetRegistry::RegisterMCInstrInfo(*T, createPPCMCInstrInfo);
304 
305     // Register the MC register info.
306     TargetRegistry::RegisterMCRegInfo(*T, createPPCMCRegisterInfo);
307 
308     // Register the MC subtarget info.
309     TargetRegistry::RegisterMCSubtargetInfo(*T, createPPCMCSubtargetInfo);
310 
311     // Register the MC Code Emitter
312     TargetRegistry::RegisterMCCodeEmitter(*T, createPPCMCCodeEmitter);
313 
314     // Register the asm backend.
315     TargetRegistry::RegisterMCAsmBackend(*T, createPPCAsmBackend);
316 
317     // Register the object target streamer.
318     TargetRegistry::RegisterObjectTargetStreamer(*T,
319                                                  createObjectTargetStreamer);
320 
321     // Register the asm target streamer.
322     TargetRegistry::RegisterAsmTargetStreamer(*T, createAsmTargetStreamer);
323 
324     // Register the MCInstPrinter.
325     TargetRegistry::RegisterMCInstPrinter(*T, createPPCMCInstPrinter);
326   }
327 }
328