1 //===-- ARMMCTargetDesc.cpp - ARM 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 ARM specific target descriptions.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #include "ARMMCTargetDesc.h"
15 #include "ARMBaseInfo.h"
16 #include "ARMMCAsmInfo.h"
17 #include "InstPrinter/ARMInstPrinter.h"
18 #include "llvm/ADT/Triple.h"
19 #include "llvm/MC/MCELFStreamer.h"
20 #include "llvm/MC/MCInstrAnalysis.h"
21 #include "llvm/MC/MCInstrInfo.h"
22 #include "llvm/MC/MCRegisterInfo.h"
23 #include "llvm/MC/MCStreamer.h"
24 #include "llvm/MC/MCSubtargetInfo.h"
25 #include "llvm/Support/ErrorHandling.h"
26 #include "llvm/Support/TargetParser.h"
27 #include "llvm/Support/TargetRegistry.h"
28 
29 using namespace llvm;
30 
31 #define GET_REGINFO_MC_DESC
32 #include "ARMGenRegisterInfo.inc"
33 
34 static bool getMCRDeprecationInfo(MCInst &MI, const MCSubtargetInfo &STI,
35                                   std::string &Info) {
36   if (STI.getFeatureBits()[llvm::ARM::HasV7Ops] &&
37       (MI.getOperand(0).isImm() && MI.getOperand(0).getImm() == 15) &&
38       (MI.getOperand(1).isImm() && MI.getOperand(1).getImm() == 0) &&
39       // Checks for the deprecated CP15ISB encoding:
40       // mcr p15, #0, rX, c7, c5, #4
41       (MI.getOperand(3).isImm() && MI.getOperand(3).getImm() == 7)) {
42     if ((MI.getOperand(5).isImm() && MI.getOperand(5).getImm() == 4)) {
43       if (MI.getOperand(4).isImm() && MI.getOperand(4).getImm() == 5) {
44         Info = "deprecated since v7, use 'isb'";
45         return true;
46       }
47 
48       // Checks for the deprecated CP15DSB encoding:
49       // mcr p15, #0, rX, c7, c10, #4
50       if (MI.getOperand(4).isImm() && MI.getOperand(4).getImm() == 10) {
51         Info = "deprecated since v7, use 'dsb'";
52         return true;
53       }
54     }
55     // Checks for the deprecated CP15DMB encoding:
56     // mcr p15, #0, rX, c7, c10, #5
57     if (MI.getOperand(4).isImm() && MI.getOperand(4).getImm() == 10 &&
58         (MI.getOperand(5).isImm() && MI.getOperand(5).getImm() == 5)) {
59       Info = "deprecated since v7, use 'dmb'";
60       return true;
61     }
62   }
63   return false;
64 }
65 
66 static bool getITDeprecationInfo(MCInst &MI, const MCSubtargetInfo &STI,
67                                  std::string &Info) {
68   if (STI.getFeatureBits()[llvm::ARM::HasV8Ops] && MI.getOperand(1).isImm() &&
69       MI.getOperand(1).getImm() != 8) {
70     Info = "applying IT instruction to more than one subsequent instruction is "
71            "deprecated";
72     return true;
73   }
74 
75   return false;
76 }
77 
78 static bool getARMStoreDeprecationInfo(MCInst &MI, const MCSubtargetInfo &STI,
79                                        std::string &Info) {
80   assert(!STI.getFeatureBits()[llvm::ARM::ModeThumb] &&
81          "cannot predicate thumb instructions");
82 
83   assert(MI.getNumOperands() >= 4 && "expected >= 4 arguments");
84   for (unsigned OI = 4, OE = MI.getNumOperands(); OI < OE; ++OI) {
85     assert(MI.getOperand(OI).isReg() && "expected register");
86     if (MI.getOperand(OI).getReg() == ARM::SP ||
87         MI.getOperand(OI).getReg() == ARM::PC) {
88       Info = "use of SP or PC in the list is deprecated";
89       return true;
90     }
91   }
92   return false;
93 }
94 
95 static bool getARMLoadDeprecationInfo(MCInst &MI, const MCSubtargetInfo &STI,
96                                       std::string &Info) {
97   assert(!STI.getFeatureBits()[llvm::ARM::ModeThumb] &&
98          "cannot predicate thumb instructions");
99 
100   assert(MI.getNumOperands() >= 4 && "expected >= 4 arguments");
101   bool ListContainsPC = false, ListContainsLR = false;
102   for (unsigned OI = 4, OE = MI.getNumOperands(); OI < OE; ++OI) {
103     assert(MI.getOperand(OI).isReg() && "expected register");
104     switch (MI.getOperand(OI).getReg()) {
105     default:
106       break;
107     case ARM::LR:
108       ListContainsLR = true;
109       break;
110     case ARM::PC:
111       ListContainsPC = true;
112       break;
113     case ARM::SP:
114       Info = "use of SP in the list is deprecated";
115       return true;
116     }
117   }
118 
119   if (ListContainsPC && ListContainsLR) {
120     Info = "use of LR and PC simultaneously in the list is deprecated";
121     return true;
122   }
123 
124   return false;
125 }
126 
127 #define GET_INSTRINFO_MC_DESC
128 #include "ARMGenInstrInfo.inc"
129 
130 #define GET_SUBTARGETINFO_MC_DESC
131 #include "ARMGenSubtargetInfo.inc"
132 
133 std::string ARM_MC::ParseARMTriple(const Triple &TT, StringRef CPU) {
134   std::string ARMArchFeature;
135 
136   ARM::ArchKind ArchID = ARM::parseArch(TT.getArchName());
137   if (ArchID != ARM::ArchKind::INVALID &&  (CPU.empty() || CPU == "generic"))
138     ARMArchFeature = (ARMArchFeature + "+" + ARM::getArchName(ArchID)).str();
139 
140   if (TT.isThumb()) {
141     if (ARMArchFeature.empty())
142       ARMArchFeature = "+thumb-mode,+v4t";
143     else
144       ARMArchFeature += ",+thumb-mode,+v4t";
145   }
146 
147   if (TT.isOSNaCl()) {
148     if (ARMArchFeature.empty())
149       ARMArchFeature = "+nacl-trap";
150     else
151       ARMArchFeature += ",+nacl-trap";
152   }
153 
154   return ARMArchFeature;
155 }
156 
157 MCSubtargetInfo *ARM_MC::createARMMCSubtargetInfo(const Triple &TT,
158                                                   StringRef CPU, StringRef FS) {
159   std::string ArchFS = ARM_MC::ParseARMTriple(TT, CPU);
160   if (!FS.empty()) {
161     if (!ArchFS.empty())
162       ArchFS = (Twine(ArchFS) + "," + FS).str();
163     else
164       ArchFS = FS;
165   }
166 
167   return createARMMCSubtargetInfoImpl(TT, CPU, ArchFS);
168 }
169 
170 static MCInstrInfo *createARMMCInstrInfo() {
171   MCInstrInfo *X = new MCInstrInfo();
172   InitARMMCInstrInfo(X);
173   return X;
174 }
175 
176 static MCRegisterInfo *createARMMCRegisterInfo(const Triple &Triple) {
177   MCRegisterInfo *X = new MCRegisterInfo();
178   InitARMMCRegisterInfo(X, ARM::LR, 0, 0, ARM::PC);
179   return X;
180 }
181 
182 static MCAsmInfo *createARMMCAsmInfo(const MCRegisterInfo &MRI,
183                                      const Triple &TheTriple) {
184   MCAsmInfo *MAI;
185   if (TheTriple.isOSDarwin() || TheTriple.isOSBinFormatMachO())
186     MAI = new ARMMCAsmInfoDarwin(TheTriple);
187   else if (TheTriple.isWindowsMSVCEnvironment())
188     MAI = new ARMCOFFMCAsmInfoMicrosoft();
189   else if (TheTriple.isOSWindows())
190     MAI = new ARMCOFFMCAsmInfoGNU();
191   else
192     MAI = new ARMELFMCAsmInfo(TheTriple);
193 
194   unsigned Reg = MRI.getDwarfRegNum(ARM::SP, true);
195   MAI->addInitialFrameState(MCCFIInstruction::createDefCfa(nullptr, Reg, 0));
196 
197   return MAI;
198 }
199 
200 static MCStreamer *createELFStreamer(const Triple &T, MCContext &Ctx,
201                                      MCAsmBackend &MAB, raw_pwrite_stream &OS,
202                                      MCCodeEmitter *Emitter, bool RelaxAll) {
203   return createARMELFStreamer(Ctx, MAB, OS, Emitter, false,
204                               (T.getArch() == Triple::thumb ||
205                                T.getArch() == Triple::thumbeb));
206 }
207 
208 static MCStreamer *createARMMachOStreamer(MCContext &Ctx, MCAsmBackend &MAB,
209                                           raw_pwrite_stream &OS,
210                                           MCCodeEmitter *Emitter, bool RelaxAll,
211                                           bool DWARFMustBeAtTheEnd) {
212   return createMachOStreamer(Ctx, MAB, OS, Emitter, false, DWARFMustBeAtTheEnd);
213 }
214 
215 static MCInstPrinter *createARMMCInstPrinter(const Triple &T,
216                                              unsigned SyntaxVariant,
217                                              const MCAsmInfo &MAI,
218                                              const MCInstrInfo &MII,
219                                              const MCRegisterInfo &MRI) {
220   if (SyntaxVariant == 0)
221     return new ARMInstPrinter(MAI, MII, MRI);
222   return nullptr;
223 }
224 
225 static MCRelocationInfo *createARMMCRelocationInfo(const Triple &TT,
226                                                    MCContext &Ctx) {
227   if (TT.isOSBinFormatMachO())
228     return createARMMachORelocationInfo(Ctx);
229   // Default to the stock relocation info.
230   return llvm::createMCRelocationInfo(TT, Ctx);
231 }
232 
233 namespace {
234 
235 class ARMMCInstrAnalysis : public MCInstrAnalysis {
236 public:
237   ARMMCInstrAnalysis(const MCInstrInfo *Info) : MCInstrAnalysis(Info) {}
238 
239   bool isUnconditionalBranch(const MCInst &Inst) const override {
240     // BCCs with the "always" predicate are unconditional branches.
241     if (Inst.getOpcode() == ARM::Bcc && Inst.getOperand(1).getImm()==ARMCC::AL)
242       return true;
243     return MCInstrAnalysis::isUnconditionalBranch(Inst);
244   }
245 
246   bool isConditionalBranch(const MCInst &Inst) const override {
247     // BCCs with the "always" predicate are unconditional branches.
248     if (Inst.getOpcode() == ARM::Bcc && Inst.getOperand(1).getImm()==ARMCC::AL)
249       return false;
250     return MCInstrAnalysis::isConditionalBranch(Inst);
251   }
252 
253   bool evaluateBranch(const MCInst &Inst, uint64_t Addr,
254                       uint64_t Size, uint64_t &Target) const override {
255     // We only handle PCRel branches for now.
256     if (Info->get(Inst.getOpcode()).OpInfo[0].OperandType!=MCOI::OPERAND_PCREL)
257       return false;
258 
259     int64_t Imm = Inst.getOperand(0).getImm();
260     Target = Addr+Imm+8; // In ARM mode the PC is always off by 8 bytes.
261     return true;
262   }
263 };
264 
265 class ThumbMCInstrAnalysis : public ARMMCInstrAnalysis {
266 public:
267   ThumbMCInstrAnalysis(const MCInstrInfo *Info) : ARMMCInstrAnalysis(Info) {}
268 
269   bool evaluateBranch(const MCInst &Inst, uint64_t Addr,
270                       uint64_t Size, uint64_t &Target) const override {
271     // We only handle PCRel branches for now.
272     if (Info->get(Inst.getOpcode()).OpInfo[0].OperandType!=MCOI::OPERAND_PCREL)
273       return false;
274 
275     int64_t Imm = Inst.getOperand(0).getImm();
276     Target = Addr+Imm+4; // In Thumb mode the PC is always off by 4 bytes.
277     return true;
278   }
279 };
280 
281 }
282 
283 static MCInstrAnalysis *createARMMCInstrAnalysis(const MCInstrInfo *Info) {
284   return new ARMMCInstrAnalysis(Info);
285 }
286 
287 static MCInstrAnalysis *createThumbMCInstrAnalysis(const MCInstrInfo *Info) {
288   return new ThumbMCInstrAnalysis(Info);
289 }
290 
291 // Force static initialization.
292 extern "C" void LLVMInitializeARMTargetMC() {
293   for (Target *T : {&getTheARMLETarget(), &getTheARMBETarget(),
294                     &getTheThumbLETarget(), &getTheThumbBETarget()}) {
295     // Register the MC asm info.
296     RegisterMCAsmInfoFn X(*T, createARMMCAsmInfo);
297 
298     // Register the MC instruction info.
299     TargetRegistry::RegisterMCInstrInfo(*T, createARMMCInstrInfo);
300 
301     // Register the MC register info.
302     TargetRegistry::RegisterMCRegInfo(*T, createARMMCRegisterInfo);
303 
304     // Register the MC subtarget info.
305     TargetRegistry::RegisterMCSubtargetInfo(*T,
306                                             ARM_MC::createARMMCSubtargetInfo);
307 
308     TargetRegistry::RegisterELFStreamer(*T, createELFStreamer);
309     TargetRegistry::RegisterCOFFStreamer(*T, createARMWinCOFFStreamer);
310     TargetRegistry::RegisterMachOStreamer(*T, createARMMachOStreamer);
311 
312     // Register the obj target streamer.
313     TargetRegistry::RegisterObjectTargetStreamer(*T,
314                                                  createARMObjectTargetStreamer);
315 
316     // Register the asm streamer.
317     TargetRegistry::RegisterAsmTargetStreamer(*T, createARMTargetAsmStreamer);
318 
319     // Register the null TargetStreamer.
320     TargetRegistry::RegisterNullTargetStreamer(*T, createARMNullTargetStreamer);
321 
322     // Register the MCInstPrinter.
323     TargetRegistry::RegisterMCInstPrinter(*T, createARMMCInstPrinter);
324 
325     // Register the MC relocation info.
326     TargetRegistry::RegisterMCRelocationInfo(*T, createARMMCRelocationInfo);
327   }
328 
329   // Register the MC instruction analyzer.
330   for (Target *T : {&getTheARMLETarget(), &getTheARMBETarget()})
331     TargetRegistry::RegisterMCInstrAnalysis(*T, createARMMCInstrAnalysis);
332   for (Target *T : {&getTheThumbLETarget(), &getTheThumbBETarget()})
333     TargetRegistry::RegisterMCInstrAnalysis(*T, createThumbMCInstrAnalysis);
334 
335   // Register the MC Code Emitter
336   for (Target *T : {&getTheARMLETarget(), &getTheThumbLETarget()})
337     TargetRegistry::RegisterMCCodeEmitter(*T, createARMLEMCCodeEmitter);
338   for (Target *T : {&getTheARMBETarget(), &getTheThumbBETarget()})
339     TargetRegistry::RegisterMCCodeEmitter(*T, createARMBEMCCodeEmitter);
340 
341   // Register the asm backend.
342   TargetRegistry::RegisterMCAsmBackend(getTheARMLETarget(),
343                                        createARMLEAsmBackend);
344   TargetRegistry::RegisterMCAsmBackend(getTheARMBETarget(),
345                                        createARMBEAsmBackend);
346   TargetRegistry::RegisterMCAsmBackend(getTheThumbLETarget(),
347                                        createThumbLEAsmBackend);
348   TargetRegistry::RegisterMCAsmBackend(getTheThumbBETarget(),
349                                        createThumbBEAsmBackend);
350 }
351