1 //===- MIParser.cpp - Machine instructions parser implementation ----------===//
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 implements the parsing of machine instructions.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #include "MIParser.h"
15 #include "MILexer.h"
16 #include "llvm/ADT/StringMap.h"
17 #include "llvm/AsmParser/SlotMapping.h"
18 #include "llvm/CodeGen/MachineBasicBlock.h"
19 #include "llvm/CodeGen/MachineFunction.h"
20 #include "llvm/CodeGen/MachineInstr.h"
21 #include "llvm/CodeGen/MachineInstrBuilder.h"
22 #include "llvm/IR/Module.h"
23 #include "llvm/Support/raw_ostream.h"
24 #include "llvm/Support/SourceMgr.h"
25 #include "llvm/Target/TargetSubtargetInfo.h"
26 #include "llvm/Target/TargetInstrInfo.h"
27 
28 using namespace llvm;
29 
30 namespace {
31 
32 /// A wrapper struct around the 'MachineOperand' struct that includes a source
33 /// range.
34 struct MachineOperandWithLocation {
35   MachineOperand Operand;
36   StringRef::iterator Begin;
37   StringRef::iterator End;
38 
39   MachineOperandWithLocation(const MachineOperand &Operand,
40                              StringRef::iterator Begin, StringRef::iterator End)
41       : Operand(Operand), Begin(Begin), End(End) {}
42 };
43 
44 class MIParser {
45   SourceMgr &SM;
46   MachineFunction &MF;
47   SMDiagnostic &Error;
48   StringRef Source, CurrentSource;
49   MIToken Token;
50   const PerFunctionMIParsingState &PFS;
51   /// Maps from indices to unnamed global values and metadata nodes.
52   const SlotMapping &IRSlots;
53   /// Maps from instruction names to op codes.
54   StringMap<unsigned> Names2InstrOpCodes;
55   /// Maps from register names to registers.
56   StringMap<unsigned> Names2Regs;
57   /// Maps from register mask names to register masks.
58   StringMap<const uint32_t *> Names2RegMasks;
59 
60 public:
61   MIParser(SourceMgr &SM, MachineFunction &MF, SMDiagnostic &Error,
62            StringRef Source, const PerFunctionMIParsingState &PFS,
63            const SlotMapping &IRSlots);
64 
65   void lex();
66 
67   /// Report an error at the current location with the given message.
68   ///
69   /// This function always return true.
70   bool error(const Twine &Msg);
71 
72   /// Report an error at the given location with the given message.
73   ///
74   /// This function always return true.
75   bool error(StringRef::iterator Loc, const Twine &Msg);
76 
77   bool parse(MachineInstr *&MI);
78   bool parseMBB(MachineBasicBlock *&MBB);
79 
80   bool parseRegister(unsigned &Reg);
81   bool parseRegisterFlag(unsigned &Flags);
82   bool parseRegisterOperand(MachineOperand &Dest, bool IsDef = false);
83   bool parseImmediateOperand(MachineOperand &Dest);
84   bool parseMBBReference(MachineBasicBlock *&MBB);
85   bool parseMBBOperand(MachineOperand &Dest);
86   bool parseGlobalAddressOperand(MachineOperand &Dest);
87   bool parseMachineOperand(MachineOperand &Dest);
88 
89 private:
90   /// Convert the integer literal in the current token into an unsigned integer.
91   ///
92   /// Return true if an error occurred.
93   bool getUnsigned(unsigned &Result);
94 
95   void initNames2InstrOpCodes();
96 
97   /// Try to convert an instruction name to an opcode. Return true if the
98   /// instruction name is invalid.
99   bool parseInstrName(StringRef InstrName, unsigned &OpCode);
100 
101   bool parseInstruction(unsigned &OpCode);
102 
103   bool verifyImplicitOperands(ArrayRef<MachineOperandWithLocation> Operands,
104                               const MCInstrDesc &MCID);
105 
106   void initNames2Regs();
107 
108   /// Try to convert a register name to a register number. Return true if the
109   /// register name is invalid.
110   bool getRegisterByName(StringRef RegName, unsigned &Reg);
111 
112   void initNames2RegMasks();
113 
114   /// Check if the given identifier is a name of a register mask.
115   ///
116   /// Return null if the identifier isn't a register mask.
117   const uint32_t *getRegMask(StringRef Identifier);
118 };
119 
120 } // end anonymous namespace
121 
122 MIParser::MIParser(SourceMgr &SM, MachineFunction &MF, SMDiagnostic &Error,
123                    StringRef Source, const PerFunctionMIParsingState &PFS,
124                    const SlotMapping &IRSlots)
125     : SM(SM), MF(MF), Error(Error), Source(Source), CurrentSource(Source),
126       Token(MIToken::Error, StringRef()), PFS(PFS), IRSlots(IRSlots) {}
127 
128 void MIParser::lex() {
129   CurrentSource = lexMIToken(
130       CurrentSource, Token,
131       [this](StringRef::iterator Loc, const Twine &Msg) { error(Loc, Msg); });
132 }
133 
134 bool MIParser::error(const Twine &Msg) { return error(Token.location(), Msg); }
135 
136 bool MIParser::error(StringRef::iterator Loc, const Twine &Msg) {
137   assert(Loc >= Source.data() && Loc <= (Source.data() + Source.size()));
138   Error = SMDiagnostic(
139       SM, SMLoc(),
140       SM.getMemoryBuffer(SM.getMainFileID())->getBufferIdentifier(), 1,
141       Loc - Source.data(), SourceMgr::DK_Error, Msg.str(), Source, None, None);
142   return true;
143 }
144 
145 bool MIParser::parse(MachineInstr *&MI) {
146   lex();
147 
148   // Parse any register operands before '='
149   // TODO: Allow parsing of multiple operands before '='
150   MachineOperand MO = MachineOperand::CreateImm(0);
151   SmallVector<MachineOperandWithLocation, 8> Operands;
152   if (Token.isRegister() || Token.isRegisterFlag()) {
153     auto Loc = Token.location();
154     if (parseRegisterOperand(MO, /*IsDef=*/true))
155       return true;
156     Operands.push_back(MachineOperandWithLocation(MO, Loc, Token.location()));
157     if (Token.isNot(MIToken::equal))
158       return error("expected '='");
159     lex();
160   }
161 
162   unsigned OpCode;
163   if (Token.isError() || parseInstruction(OpCode))
164     return true;
165 
166   // TODO: Parse the instruction flags and memory operands.
167 
168   // Parse the remaining machine operands.
169   while (Token.isNot(MIToken::Eof)) {
170     auto Loc = Token.location();
171     if (parseMachineOperand(MO))
172       return true;
173     Operands.push_back(MachineOperandWithLocation(MO, Loc, Token.location()));
174     if (Token.is(MIToken::Eof))
175       break;
176     if (Token.isNot(MIToken::comma))
177       return error("expected ',' before the next machine operand");
178     lex();
179   }
180 
181   const auto &MCID = MF.getSubtarget().getInstrInfo()->get(OpCode);
182   if (!MCID.isVariadic()) {
183     // FIXME: Move the implicit operand verification to the machine verifier.
184     if (verifyImplicitOperands(Operands, MCID))
185       return true;
186   }
187 
188   // TODO: Check for extraneous machine operands.
189   MI = MF.CreateMachineInstr(MCID, DebugLoc(), /*NoImplicit=*/true);
190   for (const auto &Operand : Operands)
191     MI->addOperand(MF, Operand.Operand);
192   return false;
193 }
194 
195 bool MIParser::parseMBB(MachineBasicBlock *&MBB) {
196   lex();
197   if (Token.isNot(MIToken::MachineBasicBlock))
198     return error("expected a machine basic block reference");
199   if (parseMBBReference(MBB))
200     return true;
201   lex();
202   if (Token.isNot(MIToken::Eof))
203     return error(
204         "expected end of string after the machine basic block reference");
205   return false;
206 }
207 
208 static const char *printImplicitRegisterFlag(const MachineOperand &MO) {
209   assert(MO.isImplicit());
210   return MO.isDef() ? "implicit-def" : "implicit";
211 }
212 
213 static std::string getRegisterName(const TargetRegisterInfo *TRI,
214                                    unsigned Reg) {
215   assert(TargetRegisterInfo::isPhysicalRegister(Reg) && "expected phys reg");
216   return StringRef(TRI->getName(Reg)).lower();
217 }
218 
219 bool MIParser::verifyImplicitOperands(
220     ArrayRef<MachineOperandWithLocation> Operands, const MCInstrDesc &MCID) {
221   if (MCID.isCall())
222     // We can't verify call instructions as they can contain arbitrary implicit
223     // register and register mask operands.
224     return false;
225 
226   // Gather all the expected implicit operands.
227   SmallVector<MachineOperand, 4> ImplicitOperands;
228   if (MCID.ImplicitDefs)
229     for (const uint16_t *ImpDefs = MCID.getImplicitDefs(); *ImpDefs; ++ImpDefs)
230       ImplicitOperands.push_back(
231           MachineOperand::CreateReg(*ImpDefs, true, true));
232   if (MCID.ImplicitUses)
233     for (const uint16_t *ImpUses = MCID.getImplicitUses(); *ImpUses; ++ImpUses)
234       ImplicitOperands.push_back(
235           MachineOperand::CreateReg(*ImpUses, false, true));
236 
237   const auto *TRI = MF.getSubtarget().getRegisterInfo();
238   assert(TRI && "Expected target register info");
239   size_t I = ImplicitOperands.size(), J = Operands.size();
240   while (I) {
241     --I;
242     if (J) {
243       --J;
244       const auto &ImplicitOperand = ImplicitOperands[I];
245       const auto &Operand = Operands[J].Operand;
246       if (ImplicitOperand.isIdenticalTo(Operand))
247         continue;
248       if (Operand.isReg() && Operand.isImplicit()) {
249         return error(Operands[J].Begin,
250                      Twine("expected an implicit register operand '") +
251                          printImplicitRegisterFlag(ImplicitOperand) + " %" +
252                          getRegisterName(TRI, ImplicitOperand.getReg()) + "'");
253       }
254     }
255     // TODO: Fix source location when Operands[J].end is right before '=', i.e:
256     // insead of reporting an error at this location:
257     //            %eax = MOV32r0
258     //                 ^
259     // report the error at the following location:
260     //            %eax = MOV32r0
261     //                          ^
262     return error(J < Operands.size() ? Operands[J].End : Token.location(),
263                  Twine("missing implicit register operand '") +
264                      printImplicitRegisterFlag(ImplicitOperands[I]) + " %" +
265                      getRegisterName(TRI, ImplicitOperands[I].getReg()) + "'");
266   }
267   return false;
268 }
269 
270 bool MIParser::parseInstruction(unsigned &OpCode) {
271   if (Token.isNot(MIToken::Identifier))
272     return error("expected a machine instruction");
273   StringRef InstrName = Token.stringValue();
274   if (parseInstrName(InstrName, OpCode))
275     return error(Twine("unknown machine instruction name '") + InstrName + "'");
276   lex();
277   return false;
278 }
279 
280 bool MIParser::parseRegister(unsigned &Reg) {
281   switch (Token.kind()) {
282   case MIToken::underscore:
283     Reg = 0;
284     break;
285   case MIToken::NamedRegister: {
286     StringRef Name = Token.stringValue();
287     if (getRegisterByName(Name, Reg))
288       return error(Twine("unknown register name '") + Name + "'");
289     break;
290   }
291   case MIToken::VirtualRegister: {
292     unsigned ID;
293     if (getUnsigned(ID))
294       return true;
295     const auto RegInfo = PFS.VirtualRegisterSlots.find(ID);
296     if (RegInfo == PFS.VirtualRegisterSlots.end())
297       return error(Twine("use of undefined virtual register '%") + Twine(ID) +
298                    "'");
299     Reg = RegInfo->second;
300     break;
301   }
302   // TODO: Parse other register kinds.
303   default:
304     llvm_unreachable("The current token should be a register");
305   }
306   return false;
307 }
308 
309 bool MIParser::parseRegisterFlag(unsigned &Flags) {
310   switch (Token.kind()) {
311   case MIToken::kw_implicit:
312     Flags |= RegState::Implicit;
313     break;
314   case MIToken::kw_implicit_define:
315     Flags |= RegState::ImplicitDefine;
316     break;
317   case MIToken::kw_dead:
318     Flags |= RegState::Dead;
319     break;
320   case MIToken::kw_killed:
321     Flags |= RegState::Kill;
322     break;
323   case MIToken::kw_undef:
324     Flags |= RegState::Undef;
325     break;
326   // TODO: report an error when we specify the same flag more than once.
327   // TODO: parse the other register flags.
328   default:
329     llvm_unreachable("The current token should be a register flag");
330   }
331   lex();
332   return false;
333 }
334 
335 bool MIParser::parseRegisterOperand(MachineOperand &Dest, bool IsDef) {
336   unsigned Reg;
337   unsigned Flags = IsDef ? RegState::Define : 0;
338   while (Token.isRegisterFlag()) {
339     if (parseRegisterFlag(Flags))
340       return true;
341   }
342   if (!Token.isRegister())
343     return error("expected a register after register flags");
344   if (parseRegister(Reg))
345     return true;
346   lex();
347   // TODO: Parse subregister.
348   Dest = MachineOperand::CreateReg(
349       Reg, Flags & RegState::Define, Flags & RegState::Implicit,
350       Flags & RegState::Kill, Flags & RegState::Dead, Flags & RegState::Undef);
351   return false;
352 }
353 
354 bool MIParser::parseImmediateOperand(MachineOperand &Dest) {
355   assert(Token.is(MIToken::IntegerLiteral));
356   const APSInt &Int = Token.integerValue();
357   if (Int.getMinSignedBits() > 64)
358     // TODO: Replace this with an error when we can parse CIMM Machine Operands.
359     llvm_unreachable("Can't parse large integer literals yet!");
360   Dest = MachineOperand::CreateImm(Int.getExtValue());
361   lex();
362   return false;
363 }
364 
365 bool MIParser::getUnsigned(unsigned &Result) {
366   assert(Token.hasIntegerValue() && "Expected a token with an integer value");
367   const uint64_t Limit = uint64_t(std::numeric_limits<unsigned>::max()) + 1;
368   uint64_t Val64 = Token.integerValue().getLimitedValue(Limit);
369   if (Val64 == Limit)
370     return error("expected 32-bit integer (too large)");
371   Result = Val64;
372   return false;
373 }
374 
375 bool MIParser::parseMBBReference(MachineBasicBlock *&MBB) {
376   assert(Token.is(MIToken::MachineBasicBlock));
377   unsigned Number;
378   if (getUnsigned(Number))
379     return true;
380   auto MBBInfo = PFS.MBBSlots.find(Number);
381   if (MBBInfo == PFS.MBBSlots.end())
382     return error(Twine("use of undefined machine basic block #") +
383                  Twine(Number));
384   MBB = MBBInfo->second;
385   if (!Token.stringValue().empty() && Token.stringValue() != MBB->getName())
386     return error(Twine("the name of machine basic block #") + Twine(Number) +
387                  " isn't '" + Token.stringValue() + "'");
388   return false;
389 }
390 
391 bool MIParser::parseMBBOperand(MachineOperand &Dest) {
392   MachineBasicBlock *MBB;
393   if (parseMBBReference(MBB))
394     return true;
395   Dest = MachineOperand::CreateMBB(MBB);
396   lex();
397   return false;
398 }
399 
400 bool MIParser::parseGlobalAddressOperand(MachineOperand &Dest) {
401   switch (Token.kind()) {
402   case MIToken::NamedGlobalValue: {
403     auto Name = Token.stringValue();
404     const Module *M = MF.getFunction()->getParent();
405     if (const auto *GV = M->getNamedValue(Name)) {
406       Dest = MachineOperand::CreateGA(GV, /*Offset=*/0);
407       break;
408     }
409     return error(Twine("use of undefined global value '@") + Name + "'");
410   }
411   case MIToken::GlobalValue: {
412     unsigned GVIdx;
413     if (getUnsigned(GVIdx))
414       return true;
415     if (GVIdx >= IRSlots.GlobalValues.size())
416       return error(Twine("use of undefined global value '@") + Twine(GVIdx) +
417                    "'");
418     Dest = MachineOperand::CreateGA(IRSlots.GlobalValues[GVIdx],
419                                     /*Offset=*/0);
420     break;
421   }
422   default:
423     llvm_unreachable("The current token should be a global value");
424   }
425   // TODO: Parse offset and target flags.
426   lex();
427   return false;
428 }
429 
430 bool MIParser::parseMachineOperand(MachineOperand &Dest) {
431   switch (Token.kind()) {
432   case MIToken::kw_implicit:
433   case MIToken::kw_implicit_define:
434   case MIToken::kw_dead:
435   case MIToken::kw_killed:
436   case MIToken::kw_undef:
437   case MIToken::underscore:
438   case MIToken::NamedRegister:
439   case MIToken::VirtualRegister:
440     return parseRegisterOperand(Dest);
441   case MIToken::IntegerLiteral:
442     return parseImmediateOperand(Dest);
443   case MIToken::MachineBasicBlock:
444     return parseMBBOperand(Dest);
445   case MIToken::GlobalValue:
446   case MIToken::NamedGlobalValue:
447     return parseGlobalAddressOperand(Dest);
448   case MIToken::Error:
449     return true;
450   case MIToken::Identifier:
451     if (const auto *RegMask = getRegMask(Token.stringValue())) {
452       Dest = MachineOperand::CreateRegMask(RegMask);
453       lex();
454       break;
455     }
456   // fallthrough
457   default:
458     // TODO: parse the other machine operands.
459     return error("expected a machine operand");
460   }
461   return false;
462 }
463 
464 void MIParser::initNames2InstrOpCodes() {
465   if (!Names2InstrOpCodes.empty())
466     return;
467   const auto *TII = MF.getSubtarget().getInstrInfo();
468   assert(TII && "Expected target instruction info");
469   for (unsigned I = 0, E = TII->getNumOpcodes(); I < E; ++I)
470     Names2InstrOpCodes.insert(std::make_pair(StringRef(TII->getName(I)), I));
471 }
472 
473 bool MIParser::parseInstrName(StringRef InstrName, unsigned &OpCode) {
474   initNames2InstrOpCodes();
475   auto InstrInfo = Names2InstrOpCodes.find(InstrName);
476   if (InstrInfo == Names2InstrOpCodes.end())
477     return true;
478   OpCode = InstrInfo->getValue();
479   return false;
480 }
481 
482 void MIParser::initNames2Regs() {
483   if (!Names2Regs.empty())
484     return;
485   // The '%noreg' register is the register 0.
486   Names2Regs.insert(std::make_pair("noreg", 0));
487   const auto *TRI = MF.getSubtarget().getRegisterInfo();
488   assert(TRI && "Expected target register info");
489   for (unsigned I = 0, E = TRI->getNumRegs(); I < E; ++I) {
490     bool WasInserted =
491         Names2Regs.insert(std::make_pair(StringRef(TRI->getName(I)).lower(), I))
492             .second;
493     (void)WasInserted;
494     assert(WasInserted && "Expected registers to be unique case-insensitively");
495   }
496 }
497 
498 bool MIParser::getRegisterByName(StringRef RegName, unsigned &Reg) {
499   initNames2Regs();
500   auto RegInfo = Names2Regs.find(RegName);
501   if (RegInfo == Names2Regs.end())
502     return true;
503   Reg = RegInfo->getValue();
504   return false;
505 }
506 
507 void MIParser::initNames2RegMasks() {
508   if (!Names2RegMasks.empty())
509     return;
510   const auto *TRI = MF.getSubtarget().getRegisterInfo();
511   assert(TRI && "Expected target register info");
512   ArrayRef<const uint32_t *> RegMasks = TRI->getRegMasks();
513   ArrayRef<const char *> RegMaskNames = TRI->getRegMaskNames();
514   assert(RegMasks.size() == RegMaskNames.size());
515   for (size_t I = 0, E = RegMasks.size(); I < E; ++I)
516     Names2RegMasks.insert(
517         std::make_pair(StringRef(RegMaskNames[I]).lower(), RegMasks[I]));
518 }
519 
520 const uint32_t *MIParser::getRegMask(StringRef Identifier) {
521   initNames2RegMasks();
522   auto RegMaskInfo = Names2RegMasks.find(Identifier);
523   if (RegMaskInfo == Names2RegMasks.end())
524     return nullptr;
525   return RegMaskInfo->getValue();
526 }
527 
528 bool llvm::parseMachineInstr(MachineInstr *&MI, SourceMgr &SM,
529                              MachineFunction &MF, StringRef Src,
530                              const PerFunctionMIParsingState &PFS,
531                              const SlotMapping &IRSlots, SMDiagnostic &Error) {
532   return MIParser(SM, MF, Error, Src, PFS, IRSlots).parse(MI);
533 }
534 
535 bool llvm::parseMBBReference(MachineBasicBlock *&MBB, SourceMgr &SM,
536                              MachineFunction &MF, StringRef Src,
537                              const PerFunctionMIParsingState &PFS,
538                              const SlotMapping &IRSlots, SMDiagnostic &Error) {
539   return MIParser(SM, MF, Error, Src, PFS, IRSlots).parseMBB(MBB);
540 }
541