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