1 //===-- PPCMCTargetDesc.cpp - PowerPC Target Descriptions -----------------===//
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 // This file provides PowerPC specific target descriptions.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #include "MCTargetDesc/PPCMCTargetDesc.h"
15 #include "InstPrinter/PPCInstPrinter.h"
16 #include "MCTargetDesc/PPCMCAsmInfo.h"
17 #include "PPCTargetStreamer.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/Support/Casting.h"
34 #include "llvm/Support/CodeGen.h"
35 #include "llvm/Support/ErrorHandling.h"
36 #include "llvm/Support/FormattedStream.h"
37 #include "llvm/Support/TargetRegistry.h"
38 #include "llvm/Support/raw_ostream.h"
39 
40 using namespace llvm;
41 
42 #define GET_INSTRINFO_MC_DESC
43 #include "PPCGenInstrInfo.inc"
44 
45 #define GET_SUBTARGETINFO_MC_DESC
46 #include "PPCGenSubtargetInfo.inc"
47 
48 #define GET_REGINFO_MC_DESC
49 #include "PPCGenRegisterInfo.inc"
50 
51 // Pin the vtable to this file.
52 PPCTargetStreamer::PPCTargetStreamer(MCStreamer &S) : MCTargetStreamer(S) {}
53 
54 PPCTargetStreamer::~PPCTargetStreamer() = default;
55 
56 static MCInstrInfo *createPPCMCInstrInfo() {
57   MCInstrInfo *X = new MCInstrInfo();
58   InitPPCMCInstrInfo(X);
59   return X;
60 }
61 
62 static MCRegisterInfo *createPPCMCRegisterInfo(const Triple &TT) {
63   bool isPPC64 =
64       (TT.getArch() == Triple::ppc64 || TT.getArch() == Triple::ppc64le);
65   unsigned Flavour = isPPC64 ? 0 : 1;
66   unsigned RA = isPPC64 ? PPC::LR8 : PPC::LR;
67 
68   MCRegisterInfo *X = new MCRegisterInfo();
69   InitPPCMCRegisterInfo(X, RA, Flavour, Flavour);
70   return X;
71 }
72 
73 static MCSubtargetInfo *createPPCMCSubtargetInfo(const Triple &TT,
74                                                  StringRef CPU, StringRef FS) {
75   return createPPCMCSubtargetInfoImpl(TT, CPU, FS);
76 }
77 
78 static MCAsmInfo *createPPCMCAsmInfo(const MCRegisterInfo &MRI,
79                                      const Triple &TheTriple) {
80   bool isPPC64 = (TheTriple.getArch() == Triple::ppc64 ||
81                   TheTriple.getArch() == Triple::ppc64le);
82 
83   MCAsmInfo *MAI;
84   if (TheTriple.isOSDarwin())
85     MAI = new PPCMCAsmInfoDarwin(isPPC64, TheTriple);
86   else
87     MAI = new PPCELFMCAsmInfo(isPPC64, TheTriple);
88 
89   // Initial state of the frame pointer is R1.
90   unsigned Reg = isPPC64 ? PPC::X1 : PPC::R1;
91   MCCFIInstruction Inst =
92       MCCFIInstruction::createDefCfa(nullptr, MRI.getDwarfRegNum(Reg, true), 0);
93   MAI->addInitialFrameState(Inst);
94 
95   return MAI;
96 }
97 
98 namespace {
99 
100 class PPCTargetAsmStreamer : public PPCTargetStreamer {
101   formatted_raw_ostream &OS;
102 
103 public:
104   PPCTargetAsmStreamer(MCStreamer &S, formatted_raw_ostream &OS)
105       : PPCTargetStreamer(S), OS(OS) {}
106 
107   void emitTCEntry(const MCSymbol &S) override {
108     OS << "\t.tc ";
109     OS << S.getName();
110     OS << "[TC],";
111     OS << S.getName();
112     OS << '\n';
113   }
114 
115   void emitMachine(StringRef CPU) override {
116     OS << "\t.machine " << CPU << '\n';
117   }
118 
119   void emitAbiVersion(int AbiVersion) override {
120     OS << "\t.abiversion " << AbiVersion << '\n';
121   }
122 
123   void emitLocalEntry(MCSymbolELF *S, const MCExpr *LocalOffset) override {
124     const MCAsmInfo *MAI = Streamer.getContext().getAsmInfo();
125 
126     OS << "\t.localentry\t";
127     S->print(OS, MAI);
128     OS << ", ";
129     LocalOffset->print(OS, MAI);
130     OS << '\n';
131   }
132 };
133 
134 class PPCTargetELFStreamer : public PPCTargetStreamer {
135 public:
136   PPCTargetELFStreamer(MCStreamer &S) : PPCTargetStreamer(S) {}
137 
138   MCELFStreamer &getStreamer() {
139     return static_cast<MCELFStreamer &>(Streamer);
140   }
141 
142   void emitTCEntry(const MCSymbol &S) override {
143     // Creates a R_PPC64_TOC relocation
144     Streamer.EmitValueToAlignment(8);
145     Streamer.EmitSymbolValue(&S, 8);
146   }
147 
148   void emitMachine(StringRef CPU) override {
149     // FIXME: Is there anything to do in here or does this directive only
150     // limit the parser?
151   }
152 
153   void emitAbiVersion(int AbiVersion) override {
154     MCAssembler &MCA = getStreamer().getAssembler();
155     unsigned Flags = MCA.getELFHeaderEFlags();
156     Flags &= ~ELF::EF_PPC64_ABI;
157     Flags |= (AbiVersion & ELF::EF_PPC64_ABI);
158     MCA.setELFHeaderEFlags(Flags);
159   }
160 
161   void emitLocalEntry(MCSymbolELF *S, const MCExpr *LocalOffset) override {
162     MCAssembler &MCA = getStreamer().getAssembler();
163 
164     int64_t Res;
165     if (!LocalOffset->evaluateAsAbsolute(Res, MCA))
166       report_fatal_error(".localentry expression must be absolute.");
167 
168     unsigned Encoded = ELF::encodePPC64LocalEntryOffset(Res);
169     if (Res != ELF::decodePPC64LocalEntryOffset(Encoded))
170       report_fatal_error(".localentry expression cannot be encoded.");
171 
172     unsigned Other = S->getOther();
173     Other &= ~ELF::STO_PPC64_LOCAL_MASK;
174     Other |= Encoded;
175     S->setOther(Other);
176 
177     // For GAS compatibility, unless we already saw a .abiversion directive,
178     // set e_flags to indicate ELFv2 ABI.
179     unsigned Flags = MCA.getELFHeaderEFlags();
180     if ((Flags & ELF::EF_PPC64_ABI) == 0)
181       MCA.setELFHeaderEFlags(Flags | 2);
182   }
183 
184   void emitAssignment(MCSymbol *S, const MCExpr *Value) override {
185     auto *Symbol = cast<MCSymbolELF>(S);
186 
187     // When encoding an assignment to set symbol A to symbol B, also copy
188     // the st_other bits encoding the local entry point offset.
189     if (copyLocalEntry(Symbol, Value))
190       UpdateOther.insert(Symbol);
191     else
192       UpdateOther.erase(Symbol);
193   }
194 
195   void finish() override {
196     for (auto *Sym : UpdateOther)
197       copyLocalEntry(Sym, Sym->getVariableValue());
198   }
199 
200 private:
201   SmallPtrSet<MCSymbolELF *, 32> UpdateOther;
202 
203   bool copyLocalEntry(MCSymbolELF *D, const MCExpr *S) {
204     auto *Ref = dyn_cast<const MCSymbolRefExpr>(S);
205     if (!Ref)
206       return false;
207     const auto &RhsSym = cast<MCSymbolELF>(Ref->getSymbol());
208     unsigned Other = D->getOther();
209     Other &= ~ELF::STO_PPC64_LOCAL_MASK;
210     Other |= RhsSym.getOther() & ELF::STO_PPC64_LOCAL_MASK;
211     D->setOther(Other);
212     return true;
213   }
214 };
215 
216 class PPCTargetMachOStreamer : public PPCTargetStreamer {
217 public:
218   PPCTargetMachOStreamer(MCStreamer &S) : PPCTargetStreamer(S) {}
219 
220   void emitTCEntry(const MCSymbol &S) override {
221     llvm_unreachable("Unknown pseudo-op: .tc");
222   }
223 
224   void emitMachine(StringRef CPU) override {
225     // FIXME: We should update the CPUType, CPUSubType in the Object file if
226     // the new values are different from the defaults.
227   }
228 
229   void emitAbiVersion(int AbiVersion) override {
230     llvm_unreachable("Unknown pseudo-op: .abiversion");
231   }
232 
233   void emitLocalEntry(MCSymbolELF *S, const MCExpr *LocalOffset) override {
234     llvm_unreachable("Unknown pseudo-op: .localentry");
235   }
236 };
237 
238 } // end anonymous namespace
239 
240 static MCTargetStreamer *createAsmTargetStreamer(MCStreamer &S,
241                                                  formatted_raw_ostream &OS,
242                                                  MCInstPrinter *InstPrint,
243                                                  bool isVerboseAsm) {
244   return new PPCTargetAsmStreamer(S, OS);
245 }
246 
247 static MCTargetStreamer *
248 createObjectTargetStreamer(MCStreamer &S, const MCSubtargetInfo &STI) {
249   const Triple &TT = STI.getTargetTriple();
250   if (TT.isOSBinFormatELF())
251     return new PPCTargetELFStreamer(S);
252   return new PPCTargetMachOStreamer(S);
253 }
254 
255 static MCInstPrinter *createPPCMCInstPrinter(const Triple &T,
256                                              unsigned SyntaxVariant,
257                                              const MCAsmInfo &MAI,
258                                              const MCInstrInfo &MII,
259                                              const MCRegisterInfo &MRI) {
260   return new PPCInstPrinter(MAI, MII, MRI, T);
261 }
262 
263 extern "C" void LLVMInitializePowerPCTargetMC() {
264   for (Target *T :
265        {&getThePPC32Target(), &getThePPC64Target(), &getThePPC64LETarget()}) {
266     // Register the MC asm info.
267     RegisterMCAsmInfoFn C(*T, createPPCMCAsmInfo);
268 
269     // Register the MC instruction info.
270     TargetRegistry::RegisterMCInstrInfo(*T, createPPCMCInstrInfo);
271 
272     // Register the MC register info.
273     TargetRegistry::RegisterMCRegInfo(*T, createPPCMCRegisterInfo);
274 
275     // Register the MC subtarget info.
276     TargetRegistry::RegisterMCSubtargetInfo(*T, createPPCMCSubtargetInfo);
277 
278     // Register the MC Code Emitter
279     TargetRegistry::RegisterMCCodeEmitter(*T, createPPCMCCodeEmitter);
280 
281     // Register the asm backend.
282     TargetRegistry::RegisterMCAsmBackend(*T, createPPCAsmBackend);
283 
284     // Register the object target streamer.
285     TargetRegistry::RegisterObjectTargetStreamer(*T,
286                                                  createObjectTargetStreamer);
287 
288     // Register the asm target streamer.
289     TargetRegistry::RegisterAsmTargetStreamer(*T, createAsmTargetStreamer);
290 
291     // Register the MCInstPrinter.
292     TargetRegistry::RegisterMCInstPrinter(*T, createPPCMCInstPrinter);
293   }
294 }
295