1 //===- CodeGenTarget.cpp - CodeGen Target Class Wrapper -------------------===//
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 class wraps target description classes used by the various code
11 // generation TableGen backends.  This makes it easier to access the data and
12 // provides a single place that needs to check it for validity.  All of these
13 // classes abort on error conditions.
14 //
15 //===----------------------------------------------------------------------===//
16 
17 #include "CodeGenTarget.h"
18 #include "CodeGenIntrinsics.h"
19 #include "CodeGenSchedule.h"
20 #include "llvm/TableGen/Error.h"
21 #include "llvm/TableGen/Record.h"
22 #include "llvm/ADT/StringExtras.h"
23 #include "llvm/ADT/STLExtras.h"
24 #include "llvm/Support/CommandLine.h"
25 #include <algorithm>
26 using namespace llvm;
27 
28 static cl::opt<unsigned>
29 AsmParserNum("asmparsernum", cl::init(0),
30              cl::desc("Make -gen-asm-parser emit assembly parser #N"));
31 
32 static cl::opt<unsigned>
33 AsmWriterNum("asmwriternum", cl::init(0),
34              cl::desc("Make -gen-asm-writer emit assembly writer #N"));
35 
36 /// getValueType - Return the MVT::SimpleValueType that the specified TableGen
37 /// record corresponds to.
38 MVT::SimpleValueType llvm::getValueType(Record *Rec) {
39   return (MVT::SimpleValueType)Rec->getValueAsInt("Value");
40 }
41 
42 std::string llvm::getName(MVT::SimpleValueType T) {
43   switch (T) {
44   case MVT::Other:   return "UNKNOWN";
45   case MVT::iPTR:    return "TLI.getPointerTy()";
46   case MVT::iPTRAny: return "TLI.getPointerTy()";
47   default: return getEnumName(T);
48   }
49 }
50 
51 std::string llvm::getEnumName(MVT::SimpleValueType T) {
52   switch (T) {
53   case MVT::Other:    return "MVT::Other";
54   case MVT::i1:       return "MVT::i1";
55   case MVT::i8:       return "MVT::i8";
56   case MVT::i16:      return "MVT::i16";
57   case MVT::i32:      return "MVT::i32";
58   case MVT::i64:      return "MVT::i64";
59   case MVT::i128:     return "MVT::i128";
60   case MVT::iAny:     return "MVT::iAny";
61   case MVT::fAny:     return "MVT::fAny";
62   case MVT::vAny:     return "MVT::vAny";
63   case MVT::f16:      return "MVT::f16";
64   case MVT::f32:      return "MVT::f32";
65   case MVT::f64:      return "MVT::f64";
66   case MVT::f80:      return "MVT::f80";
67   case MVT::f128:     return "MVT::f128";
68   case MVT::ppcf128:  return "MVT::ppcf128";
69   case MVT::x86mmx:   return "MVT::x86mmx";
70   case MVT::Glue:     return "MVT::Glue";
71   case MVT::isVoid:   return "MVT::isVoid";
72   case MVT::v2i1:     return "MVT::v2i1";
73   case MVT::v4i1:     return "MVT::v4i1";
74   case MVT::v8i1:     return "MVT::v8i1";
75   case MVT::v16i1:    return "MVT::v16i1";
76   case MVT::v2i8:     return "MVT::v2i8";
77   case MVT::v4i8:     return "MVT::v4i8";
78   case MVT::v8i8:     return "MVT::v8i8";
79   case MVT::v16i8:    return "MVT::v16i8";
80   case MVT::v32i8:    return "MVT::v32i8";
81   case MVT::v1i16:    return "MVT::v1i16";
82   case MVT::v2i16:    return "MVT::v2i16";
83   case MVT::v4i16:    return "MVT::v4i16";
84   case MVT::v8i16:    return "MVT::v8i16";
85   case MVT::v16i16:   return "MVT::v16i16";
86   case MVT::v1i32:    return "MVT::v1i32";
87   case MVT::v2i32:    return "MVT::v2i32";
88   case MVT::v4i32:    return "MVT::v4i32";
89   case MVT::v8i32:    return "MVT::v8i32";
90   case MVT::v16i32:   return "MVT::v16i32";
91   case MVT::v1i64:    return "MVT::v1i64";
92   case MVT::v2i64:    return "MVT::v2i64";
93   case MVT::v4i64:    return "MVT::v4i64";
94   case MVT::v8i64:    return "MVT::v8i64";
95   case MVT::v16i64:   return "MVT::v16i64";
96   case MVT::v2f16:    return "MVT::v2f16";
97   case MVT::v2f32:    return "MVT::v2f32";
98   case MVT::v4f32:    return "MVT::v4f32";
99   case MVT::v8f32:    return "MVT::v8f32";
100   case MVT::v2f64:    return "MVT::v2f64";
101   case MVT::v4f64:    return "MVT::v4f64";
102   case MVT::Metadata: return "MVT::Metadata";
103   case MVT::iPTR:     return "MVT::iPTR";
104   case MVT::iPTRAny:  return "MVT::iPTRAny";
105   case MVT::Untyped:  return "MVT::Untyped";
106   default: llvm_unreachable("ILLEGAL VALUE TYPE!");
107   }
108 }
109 
110 /// getQualifiedName - Return the name of the specified record, with a
111 /// namespace qualifier if the record contains one.
112 ///
113 std::string llvm::getQualifiedName(const Record *R) {
114   std::string Namespace;
115   if (R->getValue("Namespace"))
116      Namespace = R->getValueAsString("Namespace");
117   if (Namespace.empty()) return R->getName();
118   return Namespace + "::" + R->getName();
119 }
120 
121 
122 /// getTarget - Return the current instance of the Target class.
123 ///
124 CodeGenTarget::CodeGenTarget(RecordKeeper &records)
125   : Records(records), RegBank(0), SchedModels(0) {
126   std::vector<Record*> Targets = Records.getAllDerivedDefinitions("Target");
127   if (Targets.size() == 0)
128     PrintFatalError("ERROR: No 'Target' subclasses defined!");
129   if (Targets.size() != 1)
130     PrintFatalError("ERROR: Multiple subclasses of Target defined!");
131   TargetRec = Targets[0];
132 }
133 
134 CodeGenTarget::~CodeGenTarget() {
135   delete RegBank;
136   delete SchedModels;
137 }
138 
139 const std::string &CodeGenTarget::getName() const {
140   return TargetRec->getName();
141 }
142 
143 std::string CodeGenTarget::getInstNamespace() const {
144   for (inst_iterator i = inst_begin(), e = inst_end(); i != e; ++i) {
145     // Make sure not to pick up "TargetOpcode" by accidentally getting
146     // the namespace off the PHI instruction or something.
147     if ((*i)->Namespace != "TargetOpcode")
148       return (*i)->Namespace;
149   }
150 
151   return "";
152 }
153 
154 Record *CodeGenTarget::getInstructionSet() const {
155   return TargetRec->getValueAsDef("InstructionSet");
156 }
157 
158 
159 /// getAsmParser - Return the AssemblyParser definition for this target.
160 ///
161 Record *CodeGenTarget::getAsmParser() const {
162   std::vector<Record*> LI = TargetRec->getValueAsListOfDefs("AssemblyParsers");
163   if (AsmParserNum >= LI.size())
164     PrintFatalError("Target does not have an AsmParser #" + utostr(AsmParserNum) + "!");
165   return LI[AsmParserNum];
166 }
167 
168 /// getAsmParserVariant - Return the AssmblyParserVariant definition for
169 /// this target.
170 ///
171 Record *CodeGenTarget::getAsmParserVariant(unsigned i) const {
172   std::vector<Record*> LI =
173     TargetRec->getValueAsListOfDefs("AssemblyParserVariants");
174   if (i >= LI.size())
175     PrintFatalError("Target does not have an AsmParserVariant #" + utostr(i) + "!");
176   return LI[i];
177 }
178 
179 /// getAsmParserVariantCount - Return the AssmblyParserVariant definition
180 /// available for this target.
181 ///
182 unsigned CodeGenTarget::getAsmParserVariantCount() const {
183   std::vector<Record*> LI =
184     TargetRec->getValueAsListOfDefs("AssemblyParserVariants");
185   return LI.size();
186 }
187 
188 /// getAsmWriter - Return the AssemblyWriter definition for this target.
189 ///
190 Record *CodeGenTarget::getAsmWriter() const {
191   std::vector<Record*> LI = TargetRec->getValueAsListOfDefs("AssemblyWriters");
192   if (AsmWriterNum >= LI.size())
193     PrintFatalError("Target does not have an AsmWriter #" + utostr(AsmWriterNum) + "!");
194   return LI[AsmWriterNum];
195 }
196 
197 CodeGenRegBank &CodeGenTarget::getRegBank() const {
198   if (!RegBank)
199     RegBank = new CodeGenRegBank(Records);
200   return *RegBank;
201 }
202 
203 void CodeGenTarget::ReadRegAltNameIndices() const {
204   RegAltNameIndices = Records.getAllDerivedDefinitions("RegAltNameIndex");
205   std::sort(RegAltNameIndices.begin(), RegAltNameIndices.end(), LessRecord());
206 }
207 
208 /// getRegisterByName - If there is a register with the specific AsmName,
209 /// return it.
210 const CodeGenRegister *CodeGenTarget::getRegisterByName(StringRef Name) const {
211   const StringMap<CodeGenRegister*> &Regs = getRegBank().getRegistersByName();
212   StringMap<CodeGenRegister*>::const_iterator I = Regs.find(Name);
213   if (I == Regs.end())
214     return 0;
215   return I->second;
216 }
217 
218 std::vector<MVT::SimpleValueType> CodeGenTarget::
219 getRegisterVTs(Record *R) const {
220   const CodeGenRegister *Reg = getRegBank().getReg(R);
221   std::vector<MVT::SimpleValueType> Result;
222   ArrayRef<CodeGenRegisterClass*> RCs = getRegBank().getRegClasses();
223   for (unsigned i = 0, e = RCs.size(); i != e; ++i) {
224     const CodeGenRegisterClass &RC = *RCs[i];
225     if (RC.contains(Reg)) {
226       const std::vector<MVT::SimpleValueType> &InVTs = RC.getValueTypes();
227       Result.insert(Result.end(), InVTs.begin(), InVTs.end());
228     }
229   }
230 
231   // Remove duplicates.
232   array_pod_sort(Result.begin(), Result.end());
233   Result.erase(std::unique(Result.begin(), Result.end()), Result.end());
234   return Result;
235 }
236 
237 
238 void CodeGenTarget::ReadLegalValueTypes() const {
239   ArrayRef<CodeGenRegisterClass*> RCs = getRegBank().getRegClasses();
240   for (unsigned i = 0, e = RCs.size(); i != e; ++i)
241     for (unsigned ri = 0, re = RCs[i]->VTs.size(); ri != re; ++ri)
242       LegalValueTypes.push_back(RCs[i]->VTs[ri]);
243 
244   // Remove duplicates.
245   std::sort(LegalValueTypes.begin(), LegalValueTypes.end());
246   LegalValueTypes.erase(std::unique(LegalValueTypes.begin(),
247                                     LegalValueTypes.end()),
248                         LegalValueTypes.end());
249 }
250 
251 CodeGenSchedModels &CodeGenTarget::getSchedModels() const {
252   if (!SchedModels)
253     SchedModels = new CodeGenSchedModels(Records, *this);
254   return *SchedModels;
255 }
256 
257 void CodeGenTarget::ReadInstructions() const {
258   std::vector<Record*> Insts = Records.getAllDerivedDefinitions("Instruction");
259   if (Insts.size() <= 2)
260     PrintFatalError("No 'Instruction' subclasses defined!");
261 
262   // Parse the instructions defined in the .td file.
263   for (unsigned i = 0, e = Insts.size(); i != e; ++i)
264     Instructions[Insts[i]] = new CodeGenInstruction(Insts[i]);
265 }
266 
267 static const CodeGenInstruction *
268 GetInstByName(const char *Name,
269               const DenseMap<const Record*, CodeGenInstruction*> &Insts,
270               RecordKeeper &Records) {
271   const Record *Rec = Records.getDef(Name);
272 
273   DenseMap<const Record*, CodeGenInstruction*>::const_iterator
274     I = Insts.find(Rec);
275   if (Rec == 0 || I == Insts.end())
276     PrintFatalError(std::string("Could not find '") + Name + "' instruction!");
277   return I->second;
278 }
279 
280 namespace {
281 /// SortInstByName - Sorting predicate to sort instructions by name.
282 ///
283 struct SortInstByName {
284   bool operator()(const CodeGenInstruction *Rec1,
285                   const CodeGenInstruction *Rec2) const {
286     return Rec1->TheDef->getName() < Rec2->TheDef->getName();
287   }
288 };
289 }
290 
291 /// getInstructionsByEnumValue - Return all of the instructions defined by the
292 /// target, ordered by their enum value.
293 void CodeGenTarget::ComputeInstrsByEnum() const {
294   // The ordering here must match the ordering in TargetOpcodes.h.
295   const char *const FixedInstrs[] = {
296     "PHI",
297     "INLINEASM",
298     "PROLOG_LABEL",
299     "EH_LABEL",
300     "GC_LABEL",
301     "KILL",
302     "EXTRACT_SUBREG",
303     "INSERT_SUBREG",
304     "IMPLICIT_DEF",
305     "SUBREG_TO_REG",
306     "COPY_TO_REGCLASS",
307     "DBG_VALUE",
308     "REG_SEQUENCE",
309     "COPY",
310     "BUNDLE",
311     "LIFETIME_START",
312     "LIFETIME_END",
313     0
314   };
315   const DenseMap<const Record*, CodeGenInstruction*> &Insts = getInstructions();
316   for (const char *const *p = FixedInstrs; *p; ++p) {
317     const CodeGenInstruction *Instr = GetInstByName(*p, Insts, Records);
318     assert(Instr && "Missing target independent instruction");
319     assert(Instr->Namespace == "TargetOpcode" && "Bad namespace");
320     InstrsByEnum.push_back(Instr);
321   }
322   unsigned EndOfPredefines = InstrsByEnum.size();
323 
324   for (DenseMap<const Record*, CodeGenInstruction*>::const_iterator
325        I = Insts.begin(), E = Insts.end(); I != E; ++I) {
326     const CodeGenInstruction *CGI = I->second;
327     if (CGI->Namespace != "TargetOpcode")
328       InstrsByEnum.push_back(CGI);
329   }
330 
331   assert(InstrsByEnum.size() == Insts.size() && "Missing predefined instr");
332 
333   // All of the instructions are now in random order based on the map iteration.
334   // Sort them by name.
335   std::sort(InstrsByEnum.begin()+EndOfPredefines, InstrsByEnum.end(),
336             SortInstByName());
337 }
338 
339 
340 /// isLittleEndianEncoding - Return whether this target encodes its instruction
341 /// in little-endian format, i.e. bits laid out in the order [0..n]
342 ///
343 bool CodeGenTarget::isLittleEndianEncoding() const {
344   return getInstructionSet()->getValueAsBit("isLittleEndianEncoding");
345 }
346 
347 /// guessInstructionProperties - Return true if it's OK to guess instruction
348 /// properties instead of raising an error.
349 ///
350 /// This is configurable as a temporary migration aid. It will eventually be
351 /// permanently false.
352 bool CodeGenTarget::guessInstructionProperties() const {
353   return getInstructionSet()->getValueAsBit("guessInstructionProperties");
354 }
355 
356 //===----------------------------------------------------------------------===//
357 // ComplexPattern implementation
358 //
359 ComplexPattern::ComplexPattern(Record *R) {
360   Ty          = ::getValueType(R->getValueAsDef("Ty"));
361   NumOperands = R->getValueAsInt("NumOperands");
362   SelectFunc  = R->getValueAsString("SelectFunc");
363   RootNodes   = R->getValueAsListOfDefs("RootNodes");
364 
365   // Parse the properties.
366   Properties = 0;
367   std::vector<Record*> PropList = R->getValueAsListOfDefs("Properties");
368   for (unsigned i = 0, e = PropList.size(); i != e; ++i)
369     if (PropList[i]->getName() == "SDNPHasChain") {
370       Properties |= 1 << SDNPHasChain;
371     } else if (PropList[i]->getName() == "SDNPOptInGlue") {
372       Properties |= 1 << SDNPOptInGlue;
373     } else if (PropList[i]->getName() == "SDNPMayStore") {
374       Properties |= 1 << SDNPMayStore;
375     } else if (PropList[i]->getName() == "SDNPMayLoad") {
376       Properties |= 1 << SDNPMayLoad;
377     } else if (PropList[i]->getName() == "SDNPSideEffect") {
378       Properties |= 1 << SDNPSideEffect;
379     } else if (PropList[i]->getName() == "SDNPMemOperand") {
380       Properties |= 1 << SDNPMemOperand;
381     } else if (PropList[i]->getName() == "SDNPVariadic") {
382       Properties |= 1 << SDNPVariadic;
383     } else if (PropList[i]->getName() == "SDNPWantRoot") {
384       Properties |= 1 << SDNPWantRoot;
385     } else if (PropList[i]->getName() == "SDNPWantParent") {
386       Properties |= 1 << SDNPWantParent;
387     } else {
388       errs() << "Unsupported SD Node property '" << PropList[i]->getName()
389              << "' on ComplexPattern '" << R->getName() << "'!\n";
390       exit(1);
391     }
392 }
393 
394 //===----------------------------------------------------------------------===//
395 // CodeGenIntrinsic Implementation
396 //===----------------------------------------------------------------------===//
397 
398 std::vector<CodeGenIntrinsic> llvm::LoadIntrinsics(const RecordKeeper &RC,
399                                                    bool TargetOnly) {
400   std::vector<Record*> I = RC.getAllDerivedDefinitions("Intrinsic");
401 
402   std::vector<CodeGenIntrinsic> Result;
403 
404   for (unsigned i = 0, e = I.size(); i != e; ++i) {
405     bool isTarget = I[i]->getValueAsBit("isTarget");
406     if (isTarget == TargetOnly)
407       Result.push_back(CodeGenIntrinsic(I[i]));
408   }
409   return Result;
410 }
411 
412 CodeGenIntrinsic::CodeGenIntrinsic(Record *R) {
413   TheDef = R;
414   std::string DefName = R->getName();
415   ModRef = ReadWriteMem;
416   isOverloaded = false;
417   isCommutative = false;
418   canThrow = false;
419   isNoReturn = false;
420 
421   if (DefName.size() <= 4 ||
422       std::string(DefName.begin(), DefName.begin() + 4) != "int_")
423     PrintFatalError("Intrinsic '" + DefName + "' does not start with 'int_'!");
424 
425   EnumName = std::string(DefName.begin()+4, DefName.end());
426 
427   if (R->getValue("GCCBuiltinName"))  // Ignore a missing GCCBuiltinName field.
428     GCCBuiltinName = R->getValueAsString("GCCBuiltinName");
429 
430   TargetPrefix = R->getValueAsString("TargetPrefix");
431   Name = R->getValueAsString("LLVMName");
432 
433   if (Name == "") {
434     // If an explicit name isn't specified, derive one from the DefName.
435     Name = "llvm.";
436 
437     for (unsigned i = 0, e = EnumName.size(); i != e; ++i)
438       Name += (EnumName[i] == '_') ? '.' : EnumName[i];
439   } else {
440     // Verify it starts with "llvm.".
441     if (Name.size() <= 5 ||
442         std::string(Name.begin(), Name.begin() + 5) != "llvm.")
443       PrintFatalError("Intrinsic '" + DefName + "'s name does not start with 'llvm.'!");
444   }
445 
446   // If TargetPrefix is specified, make sure that Name starts with
447   // "llvm.<targetprefix>.".
448   if (!TargetPrefix.empty()) {
449     if (Name.size() < 6+TargetPrefix.size() ||
450         std::string(Name.begin() + 5, Name.begin() + 6 + TargetPrefix.size())
451         != (TargetPrefix + "."))
452       PrintFatalError("Intrinsic '" + DefName + "' does not start with 'llvm." +
453         TargetPrefix + ".'!");
454   }
455 
456   // Parse the list of return types.
457   std::vector<MVT::SimpleValueType> OverloadedVTs;
458   ListInit *TypeList = R->getValueAsListInit("RetTypes");
459   for (unsigned i = 0, e = TypeList->getSize(); i != e; ++i) {
460     Record *TyEl = TypeList->getElementAsRecord(i);
461     assert(TyEl->isSubClassOf("LLVMType") && "Expected a type!");
462     MVT::SimpleValueType VT;
463     if (TyEl->isSubClassOf("LLVMMatchType")) {
464       unsigned MatchTy = TyEl->getValueAsInt("Number");
465       assert(MatchTy < OverloadedVTs.size() &&
466              "Invalid matching number!");
467       VT = OverloadedVTs[MatchTy];
468       // It only makes sense to use the extended and truncated vector element
469       // variants with iAny types; otherwise, if the intrinsic is not
470       // overloaded, all the types can be specified directly.
471       assert(((!TyEl->isSubClassOf("LLVMExtendedElementVectorType") &&
472                !TyEl->isSubClassOf("LLVMTruncatedElementVectorType")) ||
473               VT == MVT::iAny || VT == MVT::vAny) &&
474              "Expected iAny or vAny type");
475     } else {
476       VT = getValueType(TyEl->getValueAsDef("VT"));
477     }
478     if (EVT(VT).isOverloaded()) {
479       OverloadedVTs.push_back(VT);
480       isOverloaded = true;
481     }
482 
483     // Reject invalid types.
484     if (VT == MVT::isVoid)
485       PrintFatalError("Intrinsic '" + DefName + " has void in result type list!");
486 
487     IS.RetVTs.push_back(VT);
488     IS.RetTypeDefs.push_back(TyEl);
489   }
490 
491   // Parse the list of parameter types.
492   TypeList = R->getValueAsListInit("ParamTypes");
493   for (unsigned i = 0, e = TypeList->getSize(); i != e; ++i) {
494     Record *TyEl = TypeList->getElementAsRecord(i);
495     assert(TyEl->isSubClassOf("LLVMType") && "Expected a type!");
496     MVT::SimpleValueType VT;
497     if (TyEl->isSubClassOf("LLVMMatchType")) {
498       unsigned MatchTy = TyEl->getValueAsInt("Number");
499       assert(MatchTy < OverloadedVTs.size() &&
500              "Invalid matching number!");
501       VT = OverloadedVTs[MatchTy];
502       // It only makes sense to use the extended and truncated vector element
503       // variants with iAny types; otherwise, if the intrinsic is not
504       // overloaded, all the types can be specified directly.
505       assert(((!TyEl->isSubClassOf("LLVMExtendedElementVectorType") &&
506                !TyEl->isSubClassOf("LLVMTruncatedElementVectorType")) ||
507               VT == MVT::iAny || VT == MVT::vAny) &&
508              "Expected iAny or vAny type");
509     } else
510       VT = getValueType(TyEl->getValueAsDef("VT"));
511 
512     if (EVT(VT).isOverloaded()) {
513       OverloadedVTs.push_back(VT);
514       isOverloaded = true;
515     }
516 
517     // Reject invalid types.
518     if (VT == MVT::isVoid && i != e-1 /*void at end means varargs*/)
519       PrintFatalError("Intrinsic '" + DefName + " has void in result type list!");
520 
521     IS.ParamVTs.push_back(VT);
522     IS.ParamTypeDefs.push_back(TyEl);
523   }
524 
525   // Parse the intrinsic properties.
526   ListInit *PropList = R->getValueAsListInit("Properties");
527   for (unsigned i = 0, e = PropList->getSize(); i != e; ++i) {
528     Record *Property = PropList->getElementAsRecord(i);
529     assert(Property->isSubClassOf("IntrinsicProperty") &&
530            "Expected a property!");
531 
532     if (Property->getName() == "IntrNoMem")
533       ModRef = NoMem;
534     else if (Property->getName() == "IntrReadArgMem")
535       ModRef = ReadArgMem;
536     else if (Property->getName() == "IntrReadMem")
537       ModRef = ReadMem;
538     else if (Property->getName() == "IntrReadWriteArgMem")
539       ModRef = ReadWriteArgMem;
540     else if (Property->getName() == "Commutative")
541       isCommutative = true;
542     else if (Property->getName() == "Throws")
543       canThrow = true;
544     else if (Property->getName() == "IntrNoReturn")
545       isNoReturn = true;
546     else if (Property->isSubClassOf("NoCapture")) {
547       unsigned ArgNo = Property->getValueAsInt("ArgNo");
548       ArgumentAttributes.push_back(std::make_pair(ArgNo, NoCapture));
549     } else
550       llvm_unreachable("Unknown property!");
551   }
552 
553   // Sort the argument attributes for later benefit.
554   std::sort(ArgumentAttributes.begin(), ArgumentAttributes.end());
555 }
556