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 "PPCMCTargetDesc.h"
15 #include "InstPrinter/PPCInstPrinter.h"
16 #include "PPCMCAsmInfo.h"
17 #include "PPCTargetStreamer.h"
18 #include "llvm/MC/MCCodeGenInfo.h"
19 #include "llvm/MC/MCContext.h"
20 #include "llvm/MC/MCELFStreamer.h"
21 #include "llvm/MC/MCExpr.h"
22 #include "llvm/MC/MCInstrInfo.h"
23 #include "llvm/MC/MCRegisterInfo.h"
24 #include "llvm/MC/MCStreamer.h"
25 #include "llvm/MC/MCSubtargetInfo.h"
26 #include "llvm/MC/MCSymbolELF.h"
27 #include "llvm/MC/MachineLocation.h"
28 #include "llvm/Support/ELF.h"
29 #include "llvm/Support/ErrorHandling.h"
30 #include "llvm/Support/FormattedStream.h"
31 #include "llvm/Support/TargetRegistry.h"
32 
33 using namespace llvm;
34 
35 #define GET_INSTRINFO_MC_DESC
36 #include "PPCGenInstrInfo.inc"
37 
38 #define GET_SUBTARGETINFO_MC_DESC
39 #include "PPCGenSubtargetInfo.inc"
40 
41 #define GET_REGINFO_MC_DESC
42 #include "PPCGenRegisterInfo.inc"
43 
44 // Pin the vtable to this file.
45 PPCTargetStreamer::~PPCTargetStreamer() {}
46 PPCTargetStreamer::PPCTargetStreamer(MCStreamer &S) : MCTargetStreamer(S) {}
47 
48 static MCInstrInfo *createPPCMCInstrInfo() {
49   MCInstrInfo *X = new MCInstrInfo();
50   InitPPCMCInstrInfo(X);
51   return X;
52 }
53 
54 static MCRegisterInfo *createPPCMCRegisterInfo(const Triple &TT) {
55   bool isPPC64 =
56       (TT.getArch() == Triple::ppc64 || TT.getArch() == Triple::ppc64le);
57   unsigned Flavour = isPPC64 ? 0 : 1;
58   unsigned RA = isPPC64 ? PPC::LR8 : PPC::LR;
59 
60   MCRegisterInfo *X = new MCRegisterInfo();
61   InitPPCMCRegisterInfo(X, RA, Flavour, Flavour);
62   return X;
63 }
64 
65 static MCSubtargetInfo *createPPCMCSubtargetInfo(const Triple &TT,
66                                                  StringRef CPU, StringRef FS) {
67   return createPPCMCSubtargetInfoImpl(TT, CPU, FS);
68 }
69 
70 static MCAsmInfo *createPPCMCAsmInfo(const MCRegisterInfo &MRI,
71                                      const Triple &TheTriple) {
72   bool isPPC64 = (TheTriple.getArch() == Triple::ppc64 ||
73                   TheTriple.getArch() == Triple::ppc64le);
74 
75   MCAsmInfo *MAI;
76   if (TheTriple.isOSDarwin())
77     MAI = new PPCMCAsmInfoDarwin(isPPC64, TheTriple);
78   else
79     MAI = new PPCELFMCAsmInfo(isPPC64, TheTriple);
80 
81   // Initial state of the frame pointer is R1.
82   unsigned Reg = isPPC64 ? PPC::X1 : PPC::R1;
83   MCCFIInstruction Inst =
84       MCCFIInstruction::createDefCfa(nullptr, MRI.getDwarfRegNum(Reg, true), 0);
85   MAI->addInitialFrameState(Inst);
86 
87   return MAI;
88 }
89 
90 static MCCodeGenInfo *createPPCMCCodeGenInfo(const Triple &TT, Reloc::Model RM,
91                                              CodeModel::Model CM,
92                                              CodeGenOpt::Level OL) {
93   MCCodeGenInfo *X = new MCCodeGenInfo();
94 
95   if (CM == CodeModel::Default) {
96     if (!TT.isOSDarwin() &&
97         (TT.getArch() == Triple::ppc64 || TT.getArch() == Triple::ppc64le))
98       CM = CodeModel::Medium;
99   }
100   X->initMCCodeGenInfo(RM, CM, OL);
101   return X;
102 }
103 
104 namespace {
105 class PPCTargetAsmStreamer : public PPCTargetStreamer {
106   formatted_raw_ostream &OS;
107 
108 public:
109   PPCTargetAsmStreamer(MCStreamer &S, formatted_raw_ostream &OS)
110       : PPCTargetStreamer(S), OS(OS) {}
111   void emitTCEntry(const MCSymbol &S) override {
112     OS << "\t.tc ";
113     OS << S.getName();
114     OS << "[TC],";
115     OS << S.getName();
116     OS << '\n';
117   }
118   void emitMachine(StringRef CPU) override {
119     OS << "\t.machine " << CPU << '\n';
120   }
121   void emitAbiVersion(int AbiVersion) override {
122     OS << "\t.abiversion " << AbiVersion << '\n';
123   }
124   void emitLocalEntry(MCSymbolELF *S, const MCExpr *LocalOffset) override {
125     const MCAsmInfo *MAI = Streamer.getContext().getAsmInfo();
126 
127     OS << "\t.localentry\t";
128     S->print(OS, MAI);
129     OS << ", ";
130     LocalOffset->print(OS, MAI);
131     OS << '\n';
132   }
133 };
134 
135 class PPCTargetELFStreamer : public PPCTargetStreamer {
136 public:
137   PPCTargetELFStreamer(MCStreamer &S) : PPCTargetStreamer(S) {}
138   MCELFStreamer &getStreamer() {
139     return static_cast<MCELFStreamer &>(Streamer);
140   }
141   void emitTCEntry(const MCSymbol &S) override {
142     // Creates a R_PPC64_TOC relocation
143     Streamer.EmitValueToAlignment(8);
144     Streamer.EmitSymbolValue(&S, 8);
145   }
146   void emitMachine(StringRef CPU) override {
147     // FIXME: Is there anything to do in here or does this directive only
148     // limit the parser?
149   }
150   void emitAbiVersion(int AbiVersion) override {
151     MCAssembler &MCA = getStreamer().getAssembler();
152     unsigned Flags = MCA.getELFHeaderEFlags();
153     Flags &= ~ELF::EF_PPC64_ABI;
154     Flags |= (AbiVersion & ELF::EF_PPC64_ABI);
155     MCA.setELFHeaderEFlags(Flags);
156   }
157   void emitLocalEntry(MCSymbolELF *S, const MCExpr *LocalOffset) override {
158     MCAssembler &MCA = getStreamer().getAssembler();
159 
160     int64_t Res;
161     if (!LocalOffset->evaluateAsAbsolute(Res, MCA))
162       report_fatal_error(".localentry expression must be absolute.");
163 
164     unsigned Encoded = ELF::encodePPC64LocalEntryOffset(Res);
165     if (Res != ELF::decodePPC64LocalEntryOffset(Encoded))
166       report_fatal_error(".localentry expression cannot be encoded.");
167 
168     unsigned Other = S->getOther();
169     Other &= ~ELF::STO_PPC64_LOCAL_MASK;
170     Other |= Encoded;
171     S->setOther(Other);
172 
173     // For GAS compatibility, unless we already saw a .abiversion directive,
174     // set e_flags to indicate ELFv2 ABI.
175     unsigned Flags = MCA.getELFHeaderEFlags();
176     if ((Flags & ELF::EF_PPC64_ABI) == 0)
177       MCA.setELFHeaderEFlags(Flags | 2);
178   }
179   void emitAssignment(MCSymbol *S, const MCExpr *Value) override {
180     auto *Symbol = cast<MCSymbolELF>(S);
181     // When encoding an assignment to set symbol A to symbol B, also copy
182     // the st_other bits encoding the local entry point offset.
183     if (Value->getKind() != MCExpr::SymbolRef)
184       return;
185     const auto &RhsSym = cast<MCSymbolELF>(
186         static_cast<const MCSymbolRefExpr *>(Value)->getSymbol());
187     unsigned Other = Symbol->getOther();
188     Other &= ~ELF::STO_PPC64_LOCAL_MASK;
189     Other |= RhsSym.getOther() & ELF::STO_PPC64_LOCAL_MASK;
190     Symbol->setOther(Other);
191   }
192 };
193 
194 class PPCTargetMachOStreamer : public PPCTargetStreamer {
195 public:
196   PPCTargetMachOStreamer(MCStreamer &S) : PPCTargetStreamer(S) {}
197   void emitTCEntry(const MCSymbol &S) override {
198     llvm_unreachable("Unknown pseudo-op: .tc");
199   }
200   void emitMachine(StringRef CPU) override {
201     // FIXME: We should update the CPUType, CPUSubType in the Object file if
202     // the new values are different from the defaults.
203   }
204   void emitAbiVersion(int AbiVersion) override {
205     llvm_unreachable("Unknown pseudo-op: .abiversion");
206   }
207   void emitLocalEntry(MCSymbolELF *S, const MCExpr *LocalOffset) override {
208     llvm_unreachable("Unknown pseudo-op: .localentry");
209   }
210 };
211 }
212 
213 static MCTargetStreamer *createAsmTargetStreamer(MCStreamer &S,
214                                                  formatted_raw_ostream &OS,
215                                                  MCInstPrinter *InstPrint,
216                                                  bool isVerboseAsm) {
217   return new PPCTargetAsmStreamer(S, OS);
218 }
219 
220 static MCTargetStreamer *
221 createObjectTargetStreamer(MCStreamer &S, const MCSubtargetInfo &STI) {
222   const Triple &TT = STI.getTargetTriple();
223   if (TT.isOSBinFormatELF())
224     return new PPCTargetELFStreamer(S);
225   return new PPCTargetMachOStreamer(S);
226 }
227 
228 static MCInstPrinter *createPPCMCInstPrinter(const Triple &T,
229                                              unsigned SyntaxVariant,
230                                              const MCAsmInfo &MAI,
231                                              const MCInstrInfo &MII,
232                                              const MCRegisterInfo &MRI) {
233   return new PPCInstPrinter(MAI, MII, MRI, T.isOSDarwin());
234 }
235 
236 extern "C" void LLVMInitializePowerPCTargetMC() {
237   for (Target *T : {&ThePPC32Target, &ThePPC64Target, &ThePPC64LETarget}) {
238     // Register the MC asm info.
239     RegisterMCAsmInfoFn C(*T, createPPCMCAsmInfo);
240 
241     // Register the MC codegen info.
242     TargetRegistry::RegisterMCCodeGenInfo(*T, createPPCMCCodeGenInfo);
243 
244     // Register the MC instruction info.
245     TargetRegistry::RegisterMCInstrInfo(*T, createPPCMCInstrInfo);
246 
247     // Register the MC register info.
248     TargetRegistry::RegisterMCRegInfo(*T, createPPCMCRegisterInfo);
249 
250     // Register the MC subtarget info.
251     TargetRegistry::RegisterMCSubtargetInfo(*T, createPPCMCSubtargetInfo);
252 
253     // Register the MC Code Emitter
254     TargetRegistry::RegisterMCCodeEmitter(*T, createPPCMCCodeEmitter);
255 
256     // Register the asm backend.
257     TargetRegistry::RegisterMCAsmBackend(*T, createPPCAsmBackend);
258 
259     // Register the object target streamer.
260     TargetRegistry::RegisterObjectTargetStreamer(*T,
261                                                  createObjectTargetStreamer);
262 
263     // Register the asm target streamer.
264     TargetRegistry::RegisterAsmTargetStreamer(*T, createAsmTargetStreamer);
265 
266     // Register the MCInstPrinter.
267     TargetRegistry::RegisterMCInstPrinter(*T, createPPCMCInstPrinter);
268   }
269 }
270