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/MCAsmBackend.h"
20 #include "llvm/MC/MCCodeEmitter.h"
21 #include "llvm/MC/MCELFStreamer.h"
22 #include "llvm/MC/MCInstrAnalysis.h"
23 #include "llvm/MC/MCInstrInfo.h"
24 #include "llvm/MC/MCRegisterInfo.h"
25 #include "llvm/MC/MCStreamer.h"
26 #include "llvm/MC/MCSubtargetInfo.h"
27 #include "llvm/Support/ErrorHandling.h"
28 #include "llvm/Support/TargetParser.h"
29 #include "llvm/Support/TargetRegistry.h"
30 
31 using namespace llvm;
32 
33 #define GET_REGINFO_MC_DESC
34 #include "ARMGenRegisterInfo.inc"
35 
36 static bool getMCRDeprecationInfo(MCInst &MI, const MCSubtargetInfo &STI,
37                                   std::string &Info) {
38   if (STI.getFeatureBits()[llvm::ARM::HasV7Ops] &&
39       (MI.getOperand(0).isImm() && MI.getOperand(0).getImm() == 15) &&
40       (MI.getOperand(1).isImm() && MI.getOperand(1).getImm() == 0) &&
41       // Checks for the deprecated CP15ISB encoding:
42       // mcr p15, #0, rX, c7, c5, #4
43       (MI.getOperand(3).isImm() && MI.getOperand(3).getImm() == 7)) {
44     if ((MI.getOperand(5).isImm() && MI.getOperand(5).getImm() == 4)) {
45       if (MI.getOperand(4).isImm() && MI.getOperand(4).getImm() == 5) {
46         Info = "deprecated since v7, use 'isb'";
47         return true;
48       }
49 
50       // Checks for the deprecated CP15DSB encoding:
51       // mcr p15, #0, rX, c7, c10, #4
52       if (MI.getOperand(4).isImm() && MI.getOperand(4).getImm() == 10) {
53         Info = "deprecated since v7, use 'dsb'";
54         return true;
55       }
56     }
57     // Checks for the deprecated CP15DMB encoding:
58     // mcr p15, #0, rX, c7, c10, #5
59     if (MI.getOperand(4).isImm() && MI.getOperand(4).getImm() == 10 &&
60         (MI.getOperand(5).isImm() && MI.getOperand(5).getImm() == 5)) {
61       Info = "deprecated since v7, use 'dmb'";
62       return true;
63     }
64   }
65   return false;
66 }
67 
68 static bool getITDeprecationInfo(MCInst &MI, const MCSubtargetInfo &STI,
69                                  std::string &Info) {
70   if (STI.getFeatureBits()[llvm::ARM::HasV8Ops] && MI.getOperand(1).isImm() &&
71       MI.getOperand(1).getImm() != 8) {
72     Info = "applying IT instruction to more than one subsequent instruction is "
73            "deprecated";
74     return true;
75   }
76 
77   return false;
78 }
79 
80 static bool getARMStoreDeprecationInfo(MCInst &MI, const MCSubtargetInfo &STI,
81                                        std::string &Info) {
82   assert(!STI.getFeatureBits()[llvm::ARM::ModeThumb] &&
83          "cannot predicate thumb instructions");
84 
85   assert(MI.getNumOperands() >= 4 && "expected >= 4 arguments");
86   for (unsigned OI = 4, OE = MI.getNumOperands(); OI < OE; ++OI) {
87     assert(MI.getOperand(OI).isReg() && "expected register");
88     if (MI.getOperand(OI).getReg() == ARM::SP ||
89         MI.getOperand(OI).getReg() == ARM::PC) {
90       Info = "use of SP or PC in the list is deprecated";
91       return true;
92     }
93   }
94   return false;
95 }
96 
97 static bool getARMLoadDeprecationInfo(MCInst &MI, const MCSubtargetInfo &STI,
98                                       std::string &Info) {
99   assert(!STI.getFeatureBits()[llvm::ARM::ModeThumb] &&
100          "cannot predicate thumb instructions");
101 
102   assert(MI.getNumOperands() >= 4 && "expected >= 4 arguments");
103   bool ListContainsPC = false, ListContainsLR = false;
104   for (unsigned OI = 4, OE = MI.getNumOperands(); OI < OE; ++OI) {
105     assert(MI.getOperand(OI).isReg() && "expected register");
106     switch (MI.getOperand(OI).getReg()) {
107     default:
108       break;
109     case ARM::LR:
110       ListContainsLR = true;
111       break;
112     case ARM::PC:
113       ListContainsPC = true;
114       break;
115     case ARM::SP:
116       Info = "use of SP in the list is deprecated";
117       return true;
118     }
119   }
120 
121   if (ListContainsPC && ListContainsLR) {
122     Info = "use of LR and PC simultaneously in the list is deprecated";
123     return true;
124   }
125 
126   return false;
127 }
128 
129 #define GET_INSTRINFO_MC_DESC
130 #include "ARMGenInstrInfo.inc"
131 
132 #define GET_SUBTARGETINFO_MC_DESC
133 #include "ARMGenSubtargetInfo.inc"
134 
135 std::string ARM_MC::ParseARMTriple(const Triple &TT, StringRef CPU) {
136   std::string ARMArchFeature;
137 
138   ARM::ArchKind ArchID = ARM::parseArch(TT.getArchName());
139   if (ArchID != ARM::ArchKind::INVALID &&  (CPU.empty() || CPU == "generic"))
140     ARMArchFeature = (ARMArchFeature + "+" + ARM::getArchName(ArchID)).str();
141 
142   if (TT.isThumb()) {
143     if (ARMArchFeature.empty())
144       ARMArchFeature = "+thumb-mode,+v4t";
145     else
146       ARMArchFeature += ",+thumb-mode,+v4t";
147   }
148 
149   if (TT.isOSNaCl()) {
150     if (ARMArchFeature.empty())
151       ARMArchFeature = "+nacl-trap";
152     else
153       ARMArchFeature += ",+nacl-trap";
154   }
155 
156   return ARMArchFeature;
157 }
158 
159 MCSubtargetInfo *ARM_MC::createARMMCSubtargetInfo(const Triple &TT,
160                                                   StringRef CPU, StringRef FS) {
161   std::string ArchFS = ARM_MC::ParseARMTriple(TT, CPU);
162   if (!FS.empty()) {
163     if (!ArchFS.empty())
164       ArchFS = (Twine(ArchFS) + "," + FS).str();
165     else
166       ArchFS = FS;
167   }
168 
169   return createARMMCSubtargetInfoImpl(TT, CPU, ArchFS);
170 }
171 
172 static MCInstrInfo *createARMMCInstrInfo() {
173   MCInstrInfo *X = new MCInstrInfo();
174   InitARMMCInstrInfo(X);
175   return X;
176 }
177 
178 static MCRegisterInfo *createARMMCRegisterInfo(const Triple &Triple) {
179   MCRegisterInfo *X = new MCRegisterInfo();
180   InitARMMCRegisterInfo(X, ARM::LR, 0, 0, ARM::PC);
181   return X;
182 }
183 
184 static MCAsmInfo *createARMMCAsmInfo(const MCRegisterInfo &MRI,
185                                      const Triple &TheTriple) {
186   MCAsmInfo *MAI;
187   if (TheTriple.isOSDarwin() || TheTriple.isOSBinFormatMachO())
188     MAI = new ARMMCAsmInfoDarwin(TheTriple);
189   else if (TheTriple.isWindowsMSVCEnvironment())
190     MAI = new ARMCOFFMCAsmInfoMicrosoft();
191   else if (TheTriple.isOSWindows())
192     MAI = new ARMCOFFMCAsmInfoGNU();
193   else
194     MAI = new ARMELFMCAsmInfo(TheTriple);
195 
196   unsigned Reg = MRI.getDwarfRegNum(ARM::SP, true);
197   MAI->addInitialFrameState(MCCFIInstruction::createDefCfa(nullptr, Reg, 0));
198 
199   return MAI;
200 }
201 
202 static MCStreamer *createELFStreamer(const Triple &T, MCContext &Ctx,
203                                      std::unique_ptr<MCAsmBackend> &&MAB,
204                                      raw_pwrite_stream &OS,
205                                      std::unique_ptr<MCCodeEmitter> &&Emitter,
206                                      bool RelaxAll) {
207   return createARMELFStreamer(
208       Ctx, std::move(MAB), OS, std::move(Emitter), false,
209       (T.getArch() == Triple::thumb || T.getArch() == Triple::thumbeb));
210 }
211 
212 static MCStreamer *
213 createARMMachOStreamer(MCContext &Ctx, std::unique_ptr<MCAsmBackend> &&MAB,
214                        raw_pwrite_stream &OS,
215                        std::unique_ptr<MCCodeEmitter> &&Emitter, bool RelaxAll,
216                        bool DWARFMustBeAtTheEnd) {
217   return createMachOStreamer(Ctx, std::move(MAB), OS, std::move(Emitter), false,
218                              DWARFMustBeAtTheEnd);
219 }
220 
221 static MCInstPrinter *createARMMCInstPrinter(const Triple &T,
222                                              unsigned SyntaxVariant,
223                                              const MCAsmInfo &MAI,
224                                              const MCInstrInfo &MII,
225                                              const MCRegisterInfo &MRI) {
226   if (SyntaxVariant == 0)
227     return new ARMInstPrinter(MAI, MII, MRI);
228   return nullptr;
229 }
230 
231 static MCRelocationInfo *createARMMCRelocationInfo(const Triple &TT,
232                                                    MCContext &Ctx) {
233   if (TT.isOSBinFormatMachO())
234     return createARMMachORelocationInfo(Ctx);
235   // Default to the stock relocation info.
236   return llvm::createMCRelocationInfo(TT, Ctx);
237 }
238 
239 namespace {
240 
241 class ARMMCInstrAnalysis : public MCInstrAnalysis {
242 public:
243   ARMMCInstrAnalysis(const MCInstrInfo *Info) : MCInstrAnalysis(Info) {}
244 
245   bool isUnconditionalBranch(const MCInst &Inst) const override {
246     // BCCs with the "always" predicate are unconditional branches.
247     if (Inst.getOpcode() == ARM::Bcc && Inst.getOperand(1).getImm()==ARMCC::AL)
248       return true;
249     return MCInstrAnalysis::isUnconditionalBranch(Inst);
250   }
251 
252   bool isConditionalBranch(const MCInst &Inst) const override {
253     // BCCs with the "always" predicate are unconditional branches.
254     if (Inst.getOpcode() == ARM::Bcc && Inst.getOperand(1).getImm()==ARMCC::AL)
255       return false;
256     return MCInstrAnalysis::isConditionalBranch(Inst);
257   }
258 
259   bool evaluateBranch(const MCInst &Inst, uint64_t Addr,
260                       uint64_t Size, uint64_t &Target) const override {
261     // We only handle PCRel branches for now.
262     if (Info->get(Inst.getOpcode()).OpInfo[0].OperandType!=MCOI::OPERAND_PCREL)
263       return false;
264 
265     int64_t Imm = Inst.getOperand(0).getImm();
266     Target = Addr+Imm+8; // In ARM mode the PC is always off by 8 bytes.
267     return true;
268   }
269 };
270 
271 class ThumbMCInstrAnalysis : public ARMMCInstrAnalysis {
272 public:
273   ThumbMCInstrAnalysis(const MCInstrInfo *Info) : ARMMCInstrAnalysis(Info) {}
274 
275   bool evaluateBranch(const MCInst &Inst, uint64_t Addr,
276                       uint64_t Size, uint64_t &Target) const override {
277     // We only handle PCRel branches for now.
278     if (Info->get(Inst.getOpcode()).OpInfo[0].OperandType!=MCOI::OPERAND_PCREL)
279       return false;
280 
281     int64_t Imm = Inst.getOperand(0).getImm();
282     Target = Addr+Imm+4; // In Thumb mode the PC is always off by 4 bytes.
283     return true;
284   }
285 };
286 
287 }
288 
289 static MCInstrAnalysis *createARMMCInstrAnalysis(const MCInstrInfo *Info) {
290   return new ARMMCInstrAnalysis(Info);
291 }
292 
293 static MCInstrAnalysis *createThumbMCInstrAnalysis(const MCInstrInfo *Info) {
294   return new ThumbMCInstrAnalysis(Info);
295 }
296 
297 // Force static initialization.
298 extern "C" void LLVMInitializeARMTargetMC() {
299   for (Target *T : {&getTheARMLETarget(), &getTheARMBETarget(),
300                     &getTheThumbLETarget(), &getTheThumbBETarget()}) {
301     // Register the MC asm info.
302     RegisterMCAsmInfoFn X(*T, createARMMCAsmInfo);
303 
304     // Register the MC instruction info.
305     TargetRegistry::RegisterMCInstrInfo(*T, createARMMCInstrInfo);
306 
307     // Register the MC register info.
308     TargetRegistry::RegisterMCRegInfo(*T, createARMMCRegisterInfo);
309 
310     // Register the MC subtarget info.
311     TargetRegistry::RegisterMCSubtargetInfo(*T,
312                                             ARM_MC::createARMMCSubtargetInfo);
313 
314     TargetRegistry::RegisterELFStreamer(*T, createELFStreamer);
315     TargetRegistry::RegisterCOFFStreamer(*T, createARMWinCOFFStreamer);
316     TargetRegistry::RegisterMachOStreamer(*T, createARMMachOStreamer);
317 
318     // Register the obj target streamer.
319     TargetRegistry::RegisterObjectTargetStreamer(*T,
320                                                  createARMObjectTargetStreamer);
321 
322     // Register the asm streamer.
323     TargetRegistry::RegisterAsmTargetStreamer(*T, createARMTargetAsmStreamer);
324 
325     // Register the null TargetStreamer.
326     TargetRegistry::RegisterNullTargetStreamer(*T, createARMNullTargetStreamer);
327 
328     // Register the MCInstPrinter.
329     TargetRegistry::RegisterMCInstPrinter(*T, createARMMCInstPrinter);
330 
331     // Register the MC relocation info.
332     TargetRegistry::RegisterMCRelocationInfo(*T, createARMMCRelocationInfo);
333   }
334 
335   // Register the MC instruction analyzer.
336   for (Target *T : {&getTheARMLETarget(), &getTheARMBETarget()})
337     TargetRegistry::RegisterMCInstrAnalysis(*T, createARMMCInstrAnalysis);
338   for (Target *T : {&getTheThumbLETarget(), &getTheThumbBETarget()})
339     TargetRegistry::RegisterMCInstrAnalysis(*T, createThumbMCInstrAnalysis);
340 
341   // Register the MC Code Emitter
342   for (Target *T : {&getTheARMLETarget(), &getTheThumbLETarget()})
343     TargetRegistry::RegisterMCCodeEmitter(*T, createARMLEMCCodeEmitter);
344   for (Target *T : {&getTheARMBETarget(), &getTheThumbBETarget()})
345     TargetRegistry::RegisterMCCodeEmitter(*T, createARMBEMCCodeEmitter);
346 
347   // Register the asm backend.
348   TargetRegistry::RegisterMCAsmBackend(getTheARMLETarget(),
349                                        createARMLEAsmBackend);
350   TargetRegistry::RegisterMCAsmBackend(getTheARMBETarget(),
351                                        createARMBEAsmBackend);
352   TargetRegistry::RegisterMCAsmBackend(getTheThumbLETarget(),
353                                        createThumbLEAsmBackend);
354   TargetRegistry::RegisterMCAsmBackend(getTheThumbBETarget(),
355                                        createThumbBEAsmBackend);
356 }
357