1 //===- MILexer.cpp - Machine instructions lexer 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 lexing of machine instructions.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #include "MILexer.h"
15 #include "llvm/ADT/None.h"
16 #include "llvm/ADT/StringExtras.h"
17 #include "llvm/ADT/StringSwitch.h"
18 #include "llvm/ADT/Twine.h"
19 #include <cctype>
20 
21 using namespace llvm;
22 
23 namespace {
24 
25 typedef function_ref<void(StringRef::iterator Loc, const Twine &)>
26     ErrorCallbackType;
27 
28 /// This class provides a way to iterate and get characters from the source
29 /// string.
30 class Cursor {
31   const char *Ptr;
32   const char *End;
33 
34 public:
35   Cursor(NoneType) : Ptr(nullptr), End(nullptr) {}
36 
37   explicit Cursor(StringRef Str) {
38     Ptr = Str.data();
39     End = Ptr + Str.size();
40   }
41 
42   bool isEOF() const { return Ptr == End; }
43 
44   char peek(int I = 0) const { return End - Ptr <= I ? 0 : Ptr[I]; }
45 
46   void advance(unsigned I = 1) { Ptr += I; }
47 
48   StringRef remaining() const { return StringRef(Ptr, End - Ptr); }
49 
50   StringRef upto(Cursor C) const {
51     assert(C.Ptr >= Ptr && C.Ptr <= End);
52     return StringRef(Ptr, C.Ptr - Ptr);
53   }
54 
55   StringRef::iterator location() const { return Ptr; }
56 
57   operator bool() const { return Ptr != nullptr; }
58 };
59 
60 } // end anonymous namespace
61 
62 MIToken &MIToken::reset(TokenKind Kind, StringRef Range) {
63   this->Kind = Kind;
64   this->Range = Range;
65   return *this;
66 }
67 
68 MIToken &MIToken::setStringValue(StringRef StrVal) {
69   StringValue = StrVal;
70   return *this;
71 }
72 
73 MIToken &MIToken::setOwnedStringValue(std::string StrVal) {
74   StringValueStorage = std::move(StrVal);
75   StringValue = StringValueStorage;
76   return *this;
77 }
78 
79 MIToken &MIToken::setIntegerValue(APSInt IntVal) {
80   this->IntVal = std::move(IntVal);
81   return *this;
82 }
83 
84 /// Skip the leading whitespace characters and return the updated cursor.
85 static Cursor skipWhitespace(Cursor C) {
86   while (isblank(C.peek()))
87     C.advance();
88   return C;
89 }
90 
91 static bool isNewlineChar(char C) { return C == '\n' || C == '\r'; }
92 
93 /// Skip a line comment and return the updated cursor.
94 static Cursor skipComment(Cursor C) {
95   if (C.peek() != ';')
96     return C;
97   while (!isNewlineChar(C.peek()) && !C.isEOF())
98     C.advance();
99   return C;
100 }
101 
102 /// Return true if the given character satisfies the following regular
103 /// expression: [-a-zA-Z$._0-9]
104 static bool isIdentifierChar(char C) {
105   return isalpha(C) || isdigit(C) || C == '_' || C == '-' || C == '.' ||
106          C == '$';
107 }
108 
109 /// Unescapes the given string value.
110 ///
111 /// Expects the string value to be quoted.
112 static std::string unescapeQuotedString(StringRef Value) {
113   assert(Value.front() == '"' && Value.back() == '"');
114   Cursor C = Cursor(Value.substr(1, Value.size() - 2));
115 
116   std::string Str;
117   Str.reserve(C.remaining().size());
118   while (!C.isEOF()) {
119     char Char = C.peek();
120     if (Char == '\\') {
121       if (C.peek(1) == '\\') {
122         // Two '\' become one
123         Str += '\\';
124         C.advance(2);
125         continue;
126       }
127       if (isxdigit(C.peek(1)) && isxdigit(C.peek(2))) {
128         Str += hexDigitValue(C.peek(1)) * 16 + hexDigitValue(C.peek(2));
129         C.advance(3);
130         continue;
131       }
132     }
133     Str += Char;
134     C.advance();
135   }
136   return Str;
137 }
138 
139 /// Lex a string constant using the following regular expression: \"[^\"]*\"
140 static Cursor lexStringConstant(Cursor C, ErrorCallbackType ErrorCallback) {
141   assert(C.peek() == '"');
142   for (C.advance(); C.peek() != '"'; C.advance()) {
143     if (C.isEOF() || isNewlineChar(C.peek())) {
144       ErrorCallback(
145           C.location(),
146           "end of machine instruction reached before the closing '\"'");
147       return None;
148     }
149   }
150   C.advance();
151   return C;
152 }
153 
154 static Cursor lexName(Cursor C, MIToken &Token, MIToken::TokenKind Type,
155                       unsigned PrefixLength, ErrorCallbackType ErrorCallback) {
156   auto Range = C;
157   C.advance(PrefixLength);
158   if (C.peek() == '"') {
159     if (Cursor R = lexStringConstant(C, ErrorCallback)) {
160       StringRef String = Range.upto(R);
161       Token.reset(Type, String)
162           .setOwnedStringValue(
163               unescapeQuotedString(String.drop_front(PrefixLength)));
164       return R;
165     }
166     Token.reset(MIToken::Error, Range.remaining());
167     return Range;
168   }
169   while (isIdentifierChar(C.peek()))
170     C.advance();
171   Token.reset(Type, Range.upto(C))
172       .setStringValue(Range.upto(C).drop_front(PrefixLength));
173   return C;
174 }
175 
176 static Cursor maybeLexIntegerOrScalarType(Cursor C, MIToken &Token) {
177   if ((C.peek() != 'i' && C.peek() != 's' && C.peek() != 'p') ||
178       !isdigit(C.peek(1)))
179     return None;
180   char Kind = C.peek();
181   auto Range = C;
182   C.advance(); // Skip 'i', 's', or 'p'
183   while (isdigit(C.peek()))
184     C.advance();
185 
186   Token.reset(Kind == 'i'
187                   ? MIToken::IntegerType
188                   : (Kind == 's' ? MIToken::ScalarType : MIToken::PointerType),
189               Range.upto(C));
190   return C;
191 }
192 
193 static MIToken::TokenKind getIdentifierKind(StringRef Identifier) {
194   return StringSwitch<MIToken::TokenKind>(Identifier)
195       .Case("_", MIToken::underscore)
196       .Case("implicit", MIToken::kw_implicit)
197       .Case("implicit-def", MIToken::kw_implicit_define)
198       .Case("def", MIToken::kw_def)
199       .Case("dead", MIToken::kw_dead)
200       .Case("killed", MIToken::kw_killed)
201       .Case("undef", MIToken::kw_undef)
202       .Case("internal", MIToken::kw_internal)
203       .Case("early-clobber", MIToken::kw_early_clobber)
204       .Case("debug-use", MIToken::kw_debug_use)
205       .Case("tied-def", MIToken::kw_tied_def)
206       .Case("frame-setup", MIToken::kw_frame_setup)
207       .Case("debug-location", MIToken::kw_debug_location)
208       .Case("same_value", MIToken::kw_cfi_same_value)
209       .Case("offset", MIToken::kw_cfi_offset)
210       .Case("def_cfa_register", MIToken::kw_cfi_def_cfa_register)
211       .Case("def_cfa_offset", MIToken::kw_cfi_def_cfa_offset)
212       .Case("def_cfa", MIToken::kw_cfi_def_cfa)
213       .Case("blockaddress", MIToken::kw_blockaddress)
214       .Case("intrinsic", MIToken::kw_intrinsic)
215       .Case("target-index", MIToken::kw_target_index)
216       .Case("half", MIToken::kw_half)
217       .Case("float", MIToken::kw_float)
218       .Case("double", MIToken::kw_double)
219       .Case("x86_fp80", MIToken::kw_x86_fp80)
220       .Case("fp128", MIToken::kw_fp128)
221       .Case("ppc_fp128", MIToken::kw_ppc_fp128)
222       .Case("target-flags", MIToken::kw_target_flags)
223       .Case("volatile", MIToken::kw_volatile)
224       .Case("non-temporal", MIToken::kw_non_temporal)
225       .Case("invariant", MIToken::kw_invariant)
226       .Case("align", MIToken::kw_align)
227       .Case("stack", MIToken::kw_stack)
228       .Case("got", MIToken::kw_got)
229       .Case("jump-table", MIToken::kw_jump_table)
230       .Case("constant-pool", MIToken::kw_constant_pool)
231       .Case("call-entry", MIToken::kw_call_entry)
232       .Case("liveout", MIToken::kw_liveout)
233       .Case("address-taken", MIToken::kw_address_taken)
234       .Case("landing-pad", MIToken::kw_landing_pad)
235       .Case("liveins", MIToken::kw_liveins)
236       .Case("successors", MIToken::kw_successors)
237       .Case("floatpred", MIToken::kw_floatpred)
238       .Case("intpred", MIToken::kw_intpred)
239       .Default(MIToken::Identifier);
240 }
241 
242 static Cursor maybeLexIdentifier(Cursor C, MIToken &Token) {
243   if (!isalpha(C.peek()) && C.peek() != '_')
244     return None;
245   auto Range = C;
246   while (isIdentifierChar(C.peek()))
247     C.advance();
248   auto Identifier = Range.upto(C);
249   Token.reset(getIdentifierKind(Identifier), Identifier)
250       .setStringValue(Identifier);
251   return C;
252 }
253 
254 static Cursor maybeLexMachineBasicBlock(Cursor C, MIToken &Token,
255                                         ErrorCallbackType ErrorCallback) {
256   bool IsReference = C.remaining().startswith("%bb.");
257   if (!IsReference && !C.remaining().startswith("bb."))
258     return None;
259   auto Range = C;
260   unsigned PrefixLength = IsReference ? 4 : 3;
261   C.advance(PrefixLength); // Skip '%bb.' or 'bb.'
262   if (!isdigit(C.peek())) {
263     Token.reset(MIToken::Error, C.remaining());
264     ErrorCallback(C.location(), "expected a number after '%bb.'");
265     return C;
266   }
267   auto NumberRange = C;
268   while (isdigit(C.peek()))
269     C.advance();
270   StringRef Number = NumberRange.upto(C);
271   unsigned StringOffset = PrefixLength + Number.size(); // Drop '%bb.<id>'
272   if (C.peek() == '.') {
273     C.advance(); // Skip '.'
274     ++StringOffset;
275     while (isIdentifierChar(C.peek()))
276       C.advance();
277   }
278   Token.reset(IsReference ? MIToken::MachineBasicBlock
279                           : MIToken::MachineBasicBlockLabel,
280               Range.upto(C))
281       .setIntegerValue(APSInt(Number))
282       .setStringValue(Range.upto(C).drop_front(StringOffset));
283   return C;
284 }
285 
286 static Cursor maybeLexIndex(Cursor C, MIToken &Token, StringRef Rule,
287                             MIToken::TokenKind Kind) {
288   if (!C.remaining().startswith(Rule) || !isdigit(C.peek(Rule.size())))
289     return None;
290   auto Range = C;
291   C.advance(Rule.size());
292   auto NumberRange = C;
293   while (isdigit(C.peek()))
294     C.advance();
295   Token.reset(Kind, Range.upto(C)).setIntegerValue(APSInt(NumberRange.upto(C)));
296   return C;
297 }
298 
299 static Cursor maybeLexIndexAndName(Cursor C, MIToken &Token, StringRef Rule,
300                                    MIToken::TokenKind Kind) {
301   if (!C.remaining().startswith(Rule) || !isdigit(C.peek(Rule.size())))
302     return None;
303   auto Range = C;
304   C.advance(Rule.size());
305   auto NumberRange = C;
306   while (isdigit(C.peek()))
307     C.advance();
308   StringRef Number = NumberRange.upto(C);
309   unsigned StringOffset = Rule.size() + Number.size();
310   if (C.peek() == '.') {
311     C.advance();
312     ++StringOffset;
313     while (isIdentifierChar(C.peek()))
314       C.advance();
315   }
316   Token.reset(Kind, Range.upto(C))
317       .setIntegerValue(APSInt(Number))
318       .setStringValue(Range.upto(C).drop_front(StringOffset));
319   return C;
320 }
321 
322 static Cursor maybeLexJumpTableIndex(Cursor C, MIToken &Token) {
323   return maybeLexIndex(C, Token, "%jump-table.", MIToken::JumpTableIndex);
324 }
325 
326 static Cursor maybeLexStackObject(Cursor C, MIToken &Token) {
327   return maybeLexIndexAndName(C, Token, "%stack.", MIToken::StackObject);
328 }
329 
330 static Cursor maybeLexFixedStackObject(Cursor C, MIToken &Token) {
331   return maybeLexIndex(C, Token, "%fixed-stack.", MIToken::FixedStackObject);
332 }
333 
334 static Cursor maybeLexConstantPoolItem(Cursor C, MIToken &Token) {
335   return maybeLexIndex(C, Token, "%const.", MIToken::ConstantPoolItem);
336 }
337 
338 static Cursor maybeLexSubRegisterIndex(Cursor C, MIToken &Token,
339                                        ErrorCallbackType ErrorCallback) {
340   const StringRef Rule = "%subreg.";
341   if (!C.remaining().startswith(Rule))
342     return None;
343   return lexName(C, Token, MIToken::SubRegisterIndex, Rule.size(),
344                  ErrorCallback);
345 }
346 
347 static Cursor maybeLexIRBlock(Cursor C, MIToken &Token,
348                               ErrorCallbackType ErrorCallback) {
349   const StringRef Rule = "%ir-block.";
350   if (!C.remaining().startswith(Rule))
351     return None;
352   if (isdigit(C.peek(Rule.size())))
353     return maybeLexIndex(C, Token, Rule, MIToken::IRBlock);
354   return lexName(C, Token, MIToken::NamedIRBlock, Rule.size(), ErrorCallback);
355 }
356 
357 static Cursor maybeLexIRValue(Cursor C, MIToken &Token,
358                               ErrorCallbackType ErrorCallback) {
359   const StringRef Rule = "%ir.";
360   if (!C.remaining().startswith(Rule))
361     return None;
362   if (isdigit(C.peek(Rule.size())))
363     return maybeLexIndex(C, Token, Rule, MIToken::IRValue);
364   return lexName(C, Token, MIToken::NamedIRValue, Rule.size(), ErrorCallback);
365 }
366 
367 static Cursor lexVirtualRegister(Cursor C, MIToken &Token) {
368   auto Range = C;
369   C.advance(); // Skip '%'
370   auto NumberRange = C;
371   while (isdigit(C.peek()))
372     C.advance();
373   Token.reset(MIToken::VirtualRegister, Range.upto(C))
374       .setIntegerValue(APSInt(NumberRange.upto(C)));
375   return C;
376 }
377 
378 /// Returns true for a character allowed in a register name.
379 static bool isRegisterChar(char C) {
380   return isIdentifierChar(C) && C != '.';
381 }
382 
383 static Cursor maybeLexRegister(Cursor C, MIToken &Token) {
384   if (C.peek() != '%')
385     return None;
386   if (isdigit(C.peek(1)))
387     return lexVirtualRegister(C, Token);
388   auto Range = C;
389   C.advance(); // Skip '%'
390   while (isRegisterChar(C.peek()))
391     C.advance();
392   Token.reset(MIToken::NamedRegister, Range.upto(C))
393       .setStringValue(Range.upto(C).drop_front(1)); // Drop the '%'
394   return C;
395 }
396 
397 static Cursor maybeLexGlobalValue(Cursor C, MIToken &Token,
398                                   ErrorCallbackType ErrorCallback) {
399   if (C.peek() != '@')
400     return None;
401   if (!isdigit(C.peek(1)))
402     return lexName(C, Token, MIToken::NamedGlobalValue, /*PrefixLength=*/1,
403                    ErrorCallback);
404   auto Range = C;
405   C.advance(1); // Skip the '@'
406   auto NumberRange = C;
407   while (isdigit(C.peek()))
408     C.advance();
409   Token.reset(MIToken::GlobalValue, Range.upto(C))
410       .setIntegerValue(APSInt(NumberRange.upto(C)));
411   return C;
412 }
413 
414 static Cursor maybeLexExternalSymbol(Cursor C, MIToken &Token,
415                                      ErrorCallbackType ErrorCallback) {
416   if (C.peek() != '$')
417     return None;
418   return lexName(C, Token, MIToken::ExternalSymbol, /*PrefixLength=*/1,
419                  ErrorCallback);
420 }
421 
422 static bool isValidHexFloatingPointPrefix(char C) {
423   return C == 'H' || C == 'K' || C == 'L' || C == 'M';
424 }
425 
426 static Cursor maybeLexHexFloatingPointLiteral(Cursor C, MIToken &Token) {
427   if (C.peek() != '0' || C.peek(1) != 'x')
428     return None;
429   Cursor Range = C;
430   C.advance(2); // Skip '0x'
431   if (isValidHexFloatingPointPrefix(C.peek()))
432     C.advance();
433   while (isxdigit(C.peek()))
434     C.advance();
435   Token.reset(MIToken::FloatingPointLiteral, Range.upto(C));
436   return C;
437 }
438 
439 static Cursor lexFloatingPointLiteral(Cursor Range, Cursor C, MIToken &Token) {
440   C.advance();
441   // Skip over [0-9]*([eE][-+]?[0-9]+)?
442   while (isdigit(C.peek()))
443     C.advance();
444   if ((C.peek() == 'e' || C.peek() == 'E') &&
445       (isdigit(C.peek(1)) ||
446        ((C.peek(1) == '-' || C.peek(1) == '+') && isdigit(C.peek(2))))) {
447     C.advance(2);
448     while (isdigit(C.peek()))
449       C.advance();
450   }
451   Token.reset(MIToken::FloatingPointLiteral, Range.upto(C));
452   return C;
453 }
454 
455 static Cursor maybeLexNumericalLiteral(Cursor C, MIToken &Token) {
456   if (!isdigit(C.peek()) && (C.peek() != '-' || !isdigit(C.peek(1))))
457     return None;
458   auto Range = C;
459   C.advance();
460   while (isdigit(C.peek()))
461     C.advance();
462   if (C.peek() == '.')
463     return lexFloatingPointLiteral(Range, C, Token);
464   StringRef StrVal = Range.upto(C);
465   Token.reset(MIToken::IntegerLiteral, StrVal).setIntegerValue(APSInt(StrVal));
466   return C;
467 }
468 
469 static MIToken::TokenKind getMetadataKeywordKind(StringRef Identifier) {
470   return StringSwitch<MIToken::TokenKind>(Identifier)
471       .Case("!tbaa", MIToken::md_tbaa)
472       .Case("!alias.scope", MIToken::md_alias_scope)
473       .Case("!noalias", MIToken::md_noalias)
474       .Case("!range", MIToken::md_range)
475       .Default(MIToken::Error);
476 }
477 
478 static Cursor maybeLexExlaim(Cursor C, MIToken &Token,
479                              ErrorCallbackType ErrorCallback) {
480   if (C.peek() != '!')
481     return None;
482   auto Range = C;
483   C.advance(1);
484   if (isdigit(C.peek()) || !isIdentifierChar(C.peek())) {
485     Token.reset(MIToken::exclaim, Range.upto(C));
486     return C;
487   }
488   while (isIdentifierChar(C.peek()))
489     C.advance();
490   StringRef StrVal = Range.upto(C);
491   Token.reset(getMetadataKeywordKind(StrVal), StrVal);
492   if (Token.isError())
493     ErrorCallback(Token.location(),
494                   "use of unknown metadata keyword '" + StrVal + "'");
495   return C;
496 }
497 
498 static MIToken::TokenKind symbolToken(char C) {
499   switch (C) {
500   case ',':
501     return MIToken::comma;
502   case '.':
503     return MIToken::dot;
504   case '=':
505     return MIToken::equal;
506   case ':':
507     return MIToken::colon;
508   case '(':
509     return MIToken::lparen;
510   case ')':
511     return MIToken::rparen;
512   case '{':
513     return MIToken::lbrace;
514   case '}':
515     return MIToken::rbrace;
516   case '+':
517     return MIToken::plus;
518   case '-':
519     return MIToken::minus;
520   case '<':
521     return MIToken::less;
522   case '>':
523     return MIToken::greater;
524   default:
525     return MIToken::Error;
526   }
527 }
528 
529 static Cursor maybeLexSymbol(Cursor C, MIToken &Token) {
530   MIToken::TokenKind Kind;
531   unsigned Length = 1;
532   if (C.peek() == ':' && C.peek(1) == ':') {
533     Kind = MIToken::coloncolon;
534     Length = 2;
535   } else
536     Kind = symbolToken(C.peek());
537   if (Kind == MIToken::Error)
538     return None;
539   auto Range = C;
540   C.advance(Length);
541   Token.reset(Kind, Range.upto(C));
542   return C;
543 }
544 
545 static Cursor maybeLexNewline(Cursor C, MIToken &Token) {
546   if (!isNewlineChar(C.peek()))
547     return None;
548   auto Range = C;
549   C.advance();
550   Token.reset(MIToken::Newline, Range.upto(C));
551   return C;
552 }
553 
554 static Cursor maybeLexEscapedIRValue(Cursor C, MIToken &Token,
555                                      ErrorCallbackType ErrorCallback) {
556   if (C.peek() != '`')
557     return None;
558   auto Range = C;
559   C.advance();
560   auto StrRange = C;
561   while (C.peek() != '`') {
562     if (C.isEOF() || isNewlineChar(C.peek())) {
563       ErrorCallback(
564           C.location(),
565           "end of machine instruction reached before the closing '`'");
566       Token.reset(MIToken::Error, Range.remaining());
567       return C;
568     }
569     C.advance();
570   }
571   StringRef Value = StrRange.upto(C);
572   C.advance();
573   Token.reset(MIToken::QuotedIRValue, Range.upto(C)).setStringValue(Value);
574   return C;
575 }
576 
577 StringRef llvm::lexMIToken(StringRef Source, MIToken &Token,
578                            ErrorCallbackType ErrorCallback) {
579   auto C = skipComment(skipWhitespace(Cursor(Source)));
580   if (C.isEOF()) {
581     Token.reset(MIToken::Eof, C.remaining());
582     return C.remaining();
583   }
584 
585   if (Cursor R = maybeLexIntegerOrScalarType(C, Token))
586     return R.remaining();
587   if (Cursor R = maybeLexMachineBasicBlock(C, Token, ErrorCallback))
588     return R.remaining();
589   if (Cursor R = maybeLexIdentifier(C, Token))
590     return R.remaining();
591   if (Cursor R = maybeLexJumpTableIndex(C, Token))
592     return R.remaining();
593   if (Cursor R = maybeLexStackObject(C, Token))
594     return R.remaining();
595   if (Cursor R = maybeLexFixedStackObject(C, Token))
596     return R.remaining();
597   if (Cursor R = maybeLexConstantPoolItem(C, Token))
598     return R.remaining();
599   if (Cursor R = maybeLexSubRegisterIndex(C, Token, ErrorCallback))
600     return R.remaining();
601   if (Cursor R = maybeLexIRBlock(C, Token, ErrorCallback))
602     return R.remaining();
603   if (Cursor R = maybeLexIRValue(C, Token, ErrorCallback))
604     return R.remaining();
605   if (Cursor R = maybeLexRegister(C, Token))
606     return R.remaining();
607   if (Cursor R = maybeLexGlobalValue(C, Token, ErrorCallback))
608     return R.remaining();
609   if (Cursor R = maybeLexExternalSymbol(C, Token, ErrorCallback))
610     return R.remaining();
611   if (Cursor R = maybeLexHexFloatingPointLiteral(C, Token))
612     return R.remaining();
613   if (Cursor R = maybeLexNumericalLiteral(C, Token))
614     return R.remaining();
615   if (Cursor R = maybeLexExlaim(C, Token, ErrorCallback))
616     return R.remaining();
617   if (Cursor R = maybeLexSymbol(C, Token))
618     return R.remaining();
619   if (Cursor R = maybeLexNewline(C, Token))
620     return R.remaining();
621   if (Cursor R = maybeLexEscapedIRValue(C, Token, ErrorCallback))
622     return R.remaining();
623 
624   Token.reset(MIToken::Error, C.remaining());
625   ErrorCallback(C.location(),
626                 Twine("unexpected character '") + Twine(C.peek()) + "'");
627   return C.remaining();
628 }
629