1 //===--- PPExpressions.cpp - Preprocessor Expression Evaluation -----------===// 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 Preprocessor::EvaluateDirectiveExpression method, 11 // which parses and evaluates integer constant expressions for #if directives. 12 // 13 //===----------------------------------------------------------------------===// 14 // 15 // FIXME: implement testing for #assert's. 16 // 17 //===----------------------------------------------------------------------===// 18 19 #include "clang/Lex/Preprocessor.h" 20 #include "clang/Basic/TargetInfo.h" 21 #include "clang/Lex/CodeCompletionHandler.h" 22 #include "clang/Lex/LexDiagnostic.h" 23 #include "clang/Lex/LiteralSupport.h" 24 #include "clang/Lex/MacroInfo.h" 25 #include "llvm/ADT/APSInt.h" 26 #include "llvm/Support/ErrorHandling.h" 27 #include "llvm/Support/SaveAndRestore.h" 28 using namespace clang; 29 30 namespace { 31 32 /// PPValue - Represents the value of a subexpression of a preprocessor 33 /// conditional and the source range covered by it. 34 class PPValue { 35 SourceRange Range; 36 public: 37 llvm::APSInt Val; 38 39 // Default ctor - Construct an 'invalid' PPValue. 40 PPValue(unsigned BitWidth) : Val(BitWidth) {} 41 42 unsigned getBitWidth() const { return Val.getBitWidth(); } 43 bool isUnsigned() const { return Val.isUnsigned(); } 44 45 const SourceRange &getRange() const { return Range; } 46 47 void setRange(SourceLocation L) { Range.setBegin(L); Range.setEnd(L); } 48 void setRange(SourceLocation B, SourceLocation E) { 49 Range.setBegin(B); Range.setEnd(E); 50 } 51 void setBegin(SourceLocation L) { Range.setBegin(L); } 52 void setEnd(SourceLocation L) { Range.setEnd(L); } 53 }; 54 55 } 56 57 static bool EvaluateDirectiveSubExpr(PPValue &LHS, unsigned MinPrec, 58 Token &PeekTok, bool ValueLive, 59 Preprocessor &PP); 60 61 /// DefinedTracker - This struct is used while parsing expressions to keep track 62 /// of whether !defined(X) has been seen. 63 /// 64 /// With this simple scheme, we handle the basic forms: 65 /// !defined(X) and !defined X 66 /// but we also trivially handle (silly) stuff like: 67 /// !!!defined(X) and +!defined(X) and !+!+!defined(X) and !(defined(X)). 68 struct DefinedTracker { 69 /// Each time a Value is evaluated, it returns information about whether the 70 /// parsed value is of the form defined(X), !defined(X) or is something else. 71 enum TrackerState { 72 DefinedMacro, // defined(X) 73 NotDefinedMacro, // !defined(X) 74 Unknown // Something else. 75 } State; 76 /// TheMacro - When the state is DefinedMacro or NotDefinedMacro, this 77 /// indicates the macro that was checked. 78 IdentifierInfo *TheMacro; 79 }; 80 81 /// EvaluateDefined - Process a 'defined(sym)' expression. 82 static bool EvaluateDefined(PPValue &Result, Token &PeekTok, DefinedTracker &DT, 83 bool ValueLive, Preprocessor &PP) { 84 SourceLocation beginLoc(PeekTok.getLocation()); 85 Result.setBegin(beginLoc); 86 87 // Get the next token, don't expand it. 88 PP.LexUnexpandedNonComment(PeekTok); 89 90 // Two options, it can either be a pp-identifier or a (. 91 SourceLocation LParenLoc; 92 if (PeekTok.is(tok::l_paren)) { 93 // Found a paren, remember we saw it and skip it. 94 LParenLoc = PeekTok.getLocation(); 95 PP.LexUnexpandedNonComment(PeekTok); 96 } 97 98 if (PeekTok.is(tok::code_completion)) { 99 if (PP.getCodeCompletionHandler()) 100 PP.getCodeCompletionHandler()->CodeCompleteMacroName(false); 101 PP.setCodeCompletionReached(); 102 PP.LexUnexpandedNonComment(PeekTok); 103 } 104 105 // If we don't have a pp-identifier now, this is an error. 106 if (PP.CheckMacroName(PeekTok, MU_Other)) 107 return true; 108 109 // Otherwise, we got an identifier, is it defined to something? 110 IdentifierInfo *II = PeekTok.getIdentifierInfo(); 111 Result.Val = II->hasMacroDefinition(); 112 Result.Val.setIsUnsigned(false); // Result is signed intmax_t. 113 114 MacroDirective *Macro = nullptr; 115 // If there is a macro, mark it used. 116 if (Result.Val != 0 && ValueLive) { 117 Macro = PP.getMacroDirective(II); 118 PP.markMacroAsUsed(Macro->getMacroInfo()); 119 } 120 121 // Save macro token for callback. 122 Token macroToken(PeekTok); 123 124 // If we are in parens, ensure we have a trailing ). 125 if (LParenLoc.isValid()) { 126 // Consume identifier. 127 Result.setEnd(PeekTok.getLocation()); 128 PP.LexUnexpandedNonComment(PeekTok); 129 130 if (PeekTok.isNot(tok::r_paren)) { 131 PP.Diag(PeekTok.getLocation(), diag::err_pp_expected_after) 132 << "'defined'" << tok::r_paren; 133 PP.Diag(LParenLoc, diag::note_matching) << tok::l_paren; 134 return true; 135 } 136 // Consume the ). 137 Result.setEnd(PeekTok.getLocation()); 138 PP.LexNonComment(PeekTok); 139 } else { 140 // Consume identifier. 141 Result.setEnd(PeekTok.getLocation()); 142 PP.LexNonComment(PeekTok); 143 } 144 145 // Invoke the 'defined' callback. 146 if (PPCallbacks *Callbacks = PP.getPPCallbacks()) { 147 MacroDirective *MD = Macro; 148 // Pass the MacroInfo for the macro name even if the value is dead. 149 if (!MD && Result.Val != 0) 150 MD = PP.getMacroDirective(II); 151 Callbacks->Defined(macroToken, MD, 152 SourceRange(beginLoc, PeekTok.getLocation())); 153 } 154 155 // Success, remember that we saw defined(X). 156 DT.State = DefinedTracker::DefinedMacro; 157 DT.TheMacro = II; 158 return false; 159 } 160 161 /// EvaluateValue - Evaluate the token PeekTok (and any others needed) and 162 /// return the computed value in Result. Return true if there was an error 163 /// parsing. This function also returns information about the form of the 164 /// expression in DT. See above for information on what DT means. 165 /// 166 /// If ValueLive is false, then this value is being evaluated in a context where 167 /// the result is not used. As such, avoid diagnostics that relate to 168 /// evaluation. 169 static bool EvaluateValue(PPValue &Result, Token &PeekTok, DefinedTracker &DT, 170 bool ValueLive, Preprocessor &PP) { 171 DT.State = DefinedTracker::Unknown; 172 173 if (PeekTok.is(tok::code_completion)) { 174 if (PP.getCodeCompletionHandler()) 175 PP.getCodeCompletionHandler()->CodeCompletePreprocessorExpression(); 176 PP.setCodeCompletionReached(); 177 PP.LexNonComment(PeekTok); 178 } 179 180 // If this token's spelling is a pp-identifier, check to see if it is 181 // 'defined' or if it is a macro. Note that we check here because many 182 // keywords are pp-identifiers, so we can't check the kind. 183 if (IdentifierInfo *II = PeekTok.getIdentifierInfo()) { 184 // Handle "defined X" and "defined(X)". 185 if (II->isStr("defined")) 186 return(EvaluateDefined(Result, PeekTok, DT, ValueLive, PP)); 187 188 // If this identifier isn't 'defined' or one of the special 189 // preprocessor keywords and it wasn't macro expanded, it turns 190 // into a simple 0, unless it is the C++ keyword "true", in which case it 191 // turns into "1". 192 if (ValueLive && 193 II->getTokenID() != tok::kw_true && 194 II->getTokenID() != tok::kw_false) 195 PP.Diag(PeekTok, diag::warn_pp_undef_identifier) << II; 196 Result.Val = II->getTokenID() == tok::kw_true; 197 Result.Val.setIsUnsigned(false); // "0" is signed intmax_t 0. 198 Result.setRange(PeekTok.getLocation()); 199 PP.LexNonComment(PeekTok); 200 return false; 201 } 202 203 switch (PeekTok.getKind()) { 204 default: // Non-value token. 205 PP.Diag(PeekTok, diag::err_pp_expr_bad_token_start_expr); 206 return true; 207 case tok::eod: 208 case tok::r_paren: 209 // If there is no expression, report and exit. 210 PP.Diag(PeekTok, diag::err_pp_expected_value_in_expr); 211 return true; 212 case tok::numeric_constant: { 213 SmallString<64> IntegerBuffer; 214 bool NumberInvalid = false; 215 StringRef Spelling = PP.getSpelling(PeekTok, IntegerBuffer, 216 &NumberInvalid); 217 if (NumberInvalid) 218 return true; // a diagnostic was already reported 219 220 NumericLiteralParser Literal(Spelling, PeekTok.getLocation(), PP); 221 if (Literal.hadError) 222 return true; // a diagnostic was already reported. 223 224 if (Literal.isFloatingLiteral() || Literal.isImaginary) { 225 PP.Diag(PeekTok, diag::err_pp_illegal_floating_literal); 226 return true; 227 } 228 assert(Literal.isIntegerLiteral() && "Unknown ppnumber"); 229 230 // Complain about, and drop, any ud-suffix. 231 if (Literal.hasUDSuffix()) 232 PP.Diag(PeekTok, diag::err_pp_invalid_udl) << /*integer*/1; 233 234 // 'long long' is a C99 or C++11 feature. 235 if (!PP.getLangOpts().C99 && Literal.isLongLong) { 236 if (PP.getLangOpts().CPlusPlus) 237 PP.Diag(PeekTok, 238 PP.getLangOpts().CPlusPlus11 ? 239 diag::warn_cxx98_compat_longlong : diag::ext_cxx11_longlong); 240 else 241 PP.Diag(PeekTok, diag::ext_c99_longlong); 242 } 243 244 // Parse the integer literal into Result. 245 if (Literal.GetIntegerValue(Result.Val)) { 246 // Overflow parsing integer literal. 247 if (ValueLive) 248 PP.Diag(PeekTok, diag::err_integer_literal_too_large) 249 << /* Unsigned */ 1; 250 Result.Val.setIsUnsigned(true); 251 } else { 252 // Set the signedness of the result to match whether there was a U suffix 253 // or not. 254 Result.Val.setIsUnsigned(Literal.isUnsigned); 255 256 // Detect overflow based on whether the value is signed. If signed 257 // and if the value is too large, emit a warning "integer constant is so 258 // large that it is unsigned" e.g. on 12345678901234567890 where intmax_t 259 // is 64-bits. 260 if (!Literal.isUnsigned && Result.Val.isNegative()) { 261 // Octal, hexadecimal, and binary literals are implicitly unsigned if 262 // the value does not fit into a signed integer type. 263 if (ValueLive && Literal.getRadix() == 10) 264 PP.Diag(PeekTok, diag::ext_integer_literal_too_large_for_signed); 265 Result.Val.setIsUnsigned(true); 266 } 267 } 268 269 // Consume the token. 270 Result.setRange(PeekTok.getLocation()); 271 PP.LexNonComment(PeekTok); 272 return false; 273 } 274 case tok::char_constant: // 'x' 275 case tok::wide_char_constant: // L'x' 276 case tok::utf8_char_constant: // u8'x' 277 case tok::utf16_char_constant: // u'x' 278 case tok::utf32_char_constant: { // U'x' 279 // Complain about, and drop, any ud-suffix. 280 if (PeekTok.hasUDSuffix()) 281 PP.Diag(PeekTok, diag::err_pp_invalid_udl) << /*character*/0; 282 283 SmallString<32> CharBuffer; 284 bool CharInvalid = false; 285 StringRef ThisTok = PP.getSpelling(PeekTok, CharBuffer, &CharInvalid); 286 if (CharInvalid) 287 return true; 288 289 CharLiteralParser Literal(ThisTok.begin(), ThisTok.end(), 290 PeekTok.getLocation(), PP, PeekTok.getKind()); 291 if (Literal.hadError()) 292 return true; // A diagnostic was already emitted. 293 294 // Character literals are always int or wchar_t, expand to intmax_t. 295 const TargetInfo &TI = PP.getTargetInfo(); 296 unsigned NumBits; 297 if (Literal.isMultiChar()) 298 NumBits = TI.getIntWidth(); 299 else if (Literal.isWide()) 300 NumBits = TI.getWCharWidth(); 301 else if (Literal.isUTF16()) 302 NumBits = TI.getChar16Width(); 303 else if (Literal.isUTF32()) 304 NumBits = TI.getChar32Width(); 305 else 306 NumBits = TI.getCharWidth(); 307 308 // Set the width. 309 llvm::APSInt Val(NumBits); 310 // Set the value. 311 Val = Literal.getValue(); 312 // Set the signedness. UTF-16 and UTF-32 are always unsigned 313 if (Literal.isWide()) 314 Val.setIsUnsigned(!TargetInfo::isTypeSigned(TI.getWCharType())); 315 else if (!Literal.isUTF16() && !Literal.isUTF32()) 316 Val.setIsUnsigned(!PP.getLangOpts().CharIsSigned); 317 318 if (Result.Val.getBitWidth() > Val.getBitWidth()) { 319 Result.Val = Val.extend(Result.Val.getBitWidth()); 320 } else { 321 assert(Result.Val.getBitWidth() == Val.getBitWidth() && 322 "intmax_t smaller than char/wchar_t?"); 323 Result.Val = Val; 324 } 325 326 // Consume the token. 327 Result.setRange(PeekTok.getLocation()); 328 PP.LexNonComment(PeekTok); 329 return false; 330 } 331 case tok::l_paren: { 332 SourceLocation Start = PeekTok.getLocation(); 333 PP.LexNonComment(PeekTok); // Eat the (. 334 // Parse the value and if there are any binary operators involved, parse 335 // them. 336 if (EvaluateValue(Result, PeekTok, DT, ValueLive, PP)) return true; 337 338 // If this is a silly value like (X), which doesn't need parens, check for 339 // !(defined X). 340 if (PeekTok.is(tok::r_paren)) { 341 // Just use DT unmodified as our result. 342 } else { 343 // Otherwise, we have something like (x+y), and we consumed '(x'. 344 if (EvaluateDirectiveSubExpr(Result, 1, PeekTok, ValueLive, PP)) 345 return true; 346 347 if (PeekTok.isNot(tok::r_paren)) { 348 PP.Diag(PeekTok.getLocation(), diag::err_pp_expected_rparen) 349 << Result.getRange(); 350 PP.Diag(Start, diag::note_matching) << tok::l_paren; 351 return true; 352 } 353 DT.State = DefinedTracker::Unknown; 354 } 355 Result.setRange(Start, PeekTok.getLocation()); 356 PP.LexNonComment(PeekTok); // Eat the ). 357 return false; 358 } 359 case tok::plus: { 360 SourceLocation Start = PeekTok.getLocation(); 361 // Unary plus doesn't modify the value. 362 PP.LexNonComment(PeekTok); 363 if (EvaluateValue(Result, PeekTok, DT, ValueLive, PP)) return true; 364 Result.setBegin(Start); 365 return false; 366 } 367 case tok::minus: { 368 SourceLocation Loc = PeekTok.getLocation(); 369 PP.LexNonComment(PeekTok); 370 if (EvaluateValue(Result, PeekTok, DT, ValueLive, PP)) return true; 371 Result.setBegin(Loc); 372 373 // C99 6.5.3.3p3: The sign of the result matches the sign of the operand. 374 Result.Val = -Result.Val; 375 376 // -MININT is the only thing that overflows. Unsigned never overflows. 377 bool Overflow = !Result.isUnsigned() && Result.Val.isMinSignedValue(); 378 379 // If this operator is live and overflowed, report the issue. 380 if (Overflow && ValueLive) 381 PP.Diag(Loc, diag::warn_pp_expr_overflow) << Result.getRange(); 382 383 DT.State = DefinedTracker::Unknown; 384 return false; 385 } 386 387 case tok::tilde: { 388 SourceLocation Start = PeekTok.getLocation(); 389 PP.LexNonComment(PeekTok); 390 if (EvaluateValue(Result, PeekTok, DT, ValueLive, PP)) return true; 391 Result.setBegin(Start); 392 393 // C99 6.5.3.3p4: The sign of the result matches the sign of the operand. 394 Result.Val = ~Result.Val; 395 DT.State = DefinedTracker::Unknown; 396 return false; 397 } 398 399 case tok::exclaim: { 400 SourceLocation Start = PeekTok.getLocation(); 401 PP.LexNonComment(PeekTok); 402 if (EvaluateValue(Result, PeekTok, DT, ValueLive, PP)) return true; 403 Result.setBegin(Start); 404 Result.Val = !Result.Val; 405 // C99 6.5.3.3p5: The sign of the result is 'int', aka it is signed. 406 Result.Val.setIsUnsigned(false); 407 408 if (DT.State == DefinedTracker::DefinedMacro) 409 DT.State = DefinedTracker::NotDefinedMacro; 410 else if (DT.State == DefinedTracker::NotDefinedMacro) 411 DT.State = DefinedTracker::DefinedMacro; 412 return false; 413 } 414 415 // FIXME: Handle #assert 416 } 417 } 418 419 420 421 /// getPrecedence - Return the precedence of the specified binary operator 422 /// token. This returns: 423 /// ~0 - Invalid token. 424 /// 14 -> 3 - various operators. 425 /// 0 - 'eod' or ')' 426 static unsigned getPrecedence(tok::TokenKind Kind) { 427 switch (Kind) { 428 default: return ~0U; 429 case tok::percent: 430 case tok::slash: 431 case tok::star: return 14; 432 case tok::plus: 433 case tok::minus: return 13; 434 case tok::lessless: 435 case tok::greatergreater: return 12; 436 case tok::lessequal: 437 case tok::less: 438 case tok::greaterequal: 439 case tok::greater: return 11; 440 case tok::exclaimequal: 441 case tok::equalequal: return 10; 442 case tok::amp: return 9; 443 case tok::caret: return 8; 444 case tok::pipe: return 7; 445 case tok::ampamp: return 6; 446 case tok::pipepipe: return 5; 447 case tok::question: return 4; 448 case tok::comma: return 3; 449 case tok::colon: return 2; 450 case tok::r_paren: return 0;// Lowest priority, end of expr. 451 case tok::eod: return 0;// Lowest priority, end of directive. 452 } 453 } 454 455 456 /// EvaluateDirectiveSubExpr - Evaluate the subexpression whose first token is 457 /// PeekTok, and whose precedence is PeekPrec. This returns the result in LHS. 458 /// 459 /// If ValueLive is false, then this value is being evaluated in a context where 460 /// the result is not used. As such, avoid diagnostics that relate to 461 /// evaluation, such as division by zero warnings. 462 static bool EvaluateDirectiveSubExpr(PPValue &LHS, unsigned MinPrec, 463 Token &PeekTok, bool ValueLive, 464 Preprocessor &PP) { 465 unsigned PeekPrec = getPrecedence(PeekTok.getKind()); 466 // If this token isn't valid, report the error. 467 if (PeekPrec == ~0U) { 468 PP.Diag(PeekTok.getLocation(), diag::err_pp_expr_bad_token_binop) 469 << LHS.getRange(); 470 return true; 471 } 472 473 while (1) { 474 // If this token has a lower precedence than we are allowed to parse, return 475 // it so that higher levels of the recursion can parse it. 476 if (PeekPrec < MinPrec) 477 return false; 478 479 tok::TokenKind Operator = PeekTok.getKind(); 480 481 // If this is a short-circuiting operator, see if the RHS of the operator is 482 // dead. Note that this cannot just clobber ValueLive. Consider 483 // "0 && 1 ? 4 : 1 / 0", which is parsed as "(0 && 1) ? 4 : (1 / 0)". In 484 // this example, the RHS of the && being dead does not make the rest of the 485 // expr dead. 486 bool RHSIsLive; 487 if (Operator == tok::ampamp && LHS.Val == 0) 488 RHSIsLive = false; // RHS of "0 && x" is dead. 489 else if (Operator == tok::pipepipe && LHS.Val != 0) 490 RHSIsLive = false; // RHS of "1 || x" is dead. 491 else if (Operator == tok::question && LHS.Val == 0) 492 RHSIsLive = false; // RHS (x) of "0 ? x : y" is dead. 493 else 494 RHSIsLive = ValueLive; 495 496 // Consume the operator, remembering the operator's location for reporting. 497 SourceLocation OpLoc = PeekTok.getLocation(); 498 PP.LexNonComment(PeekTok); 499 500 PPValue RHS(LHS.getBitWidth()); 501 // Parse the RHS of the operator. 502 DefinedTracker DT; 503 if (EvaluateValue(RHS, PeekTok, DT, RHSIsLive, PP)) return true; 504 505 // Remember the precedence of this operator and get the precedence of the 506 // operator immediately to the right of the RHS. 507 unsigned ThisPrec = PeekPrec; 508 PeekPrec = getPrecedence(PeekTok.getKind()); 509 510 // If this token isn't valid, report the error. 511 if (PeekPrec == ~0U) { 512 PP.Diag(PeekTok.getLocation(), diag::err_pp_expr_bad_token_binop) 513 << RHS.getRange(); 514 return true; 515 } 516 517 // Decide whether to include the next binop in this subexpression. For 518 // example, when parsing x+y*z and looking at '*', we want to recursively 519 // handle y*z as a single subexpression. We do this because the precedence 520 // of * is higher than that of +. The only strange case we have to handle 521 // here is for the ?: operator, where the precedence is actually lower than 522 // the LHS of the '?'. The grammar rule is: 523 // 524 // conditional-expression ::= 525 // logical-OR-expression ? expression : conditional-expression 526 // where 'expression' is actually comma-expression. 527 unsigned RHSPrec; 528 if (Operator == tok::question) 529 // The RHS of "?" should be maximally consumed as an expression. 530 RHSPrec = getPrecedence(tok::comma); 531 else // All others should munch while higher precedence. 532 RHSPrec = ThisPrec+1; 533 534 if (PeekPrec >= RHSPrec) { 535 if (EvaluateDirectiveSubExpr(RHS, RHSPrec, PeekTok, RHSIsLive, PP)) 536 return true; 537 PeekPrec = getPrecedence(PeekTok.getKind()); 538 } 539 assert(PeekPrec <= ThisPrec && "Recursion didn't work!"); 540 541 // Usual arithmetic conversions (C99 6.3.1.8p1): result is unsigned if 542 // either operand is unsigned. 543 llvm::APSInt Res(LHS.getBitWidth()); 544 switch (Operator) { 545 case tok::question: // No UAC for x and y in "x ? y : z". 546 case tok::lessless: // Shift amount doesn't UAC with shift value. 547 case tok::greatergreater: // Shift amount doesn't UAC with shift value. 548 case tok::comma: // Comma operands are not subject to UACs. 549 case tok::pipepipe: // Logical || does not do UACs. 550 case tok::ampamp: // Logical && does not do UACs. 551 break; // No UAC 552 default: 553 Res.setIsUnsigned(LHS.isUnsigned()|RHS.isUnsigned()); 554 // If this just promoted something from signed to unsigned, and if the 555 // value was negative, warn about it. 556 if (ValueLive && Res.isUnsigned()) { 557 if (!LHS.isUnsigned() && LHS.Val.isNegative()) 558 PP.Diag(OpLoc, diag::warn_pp_convert_lhs_to_positive) 559 << LHS.Val.toString(10, true) + " to " + 560 LHS.Val.toString(10, false) 561 << LHS.getRange() << RHS.getRange(); 562 if (!RHS.isUnsigned() && RHS.Val.isNegative()) 563 PP.Diag(OpLoc, diag::warn_pp_convert_rhs_to_positive) 564 << RHS.Val.toString(10, true) + " to " + 565 RHS.Val.toString(10, false) 566 << LHS.getRange() << RHS.getRange(); 567 } 568 LHS.Val.setIsUnsigned(Res.isUnsigned()); 569 RHS.Val.setIsUnsigned(Res.isUnsigned()); 570 } 571 572 bool Overflow = false; 573 switch (Operator) { 574 default: llvm_unreachable("Unknown operator token!"); 575 case tok::percent: 576 if (RHS.Val != 0) 577 Res = LHS.Val % RHS.Val; 578 else if (ValueLive) { 579 PP.Diag(OpLoc, diag::err_pp_remainder_by_zero) 580 << LHS.getRange() << RHS.getRange(); 581 return true; 582 } 583 break; 584 case tok::slash: 585 if (RHS.Val != 0) { 586 if (LHS.Val.isSigned()) 587 Res = llvm::APSInt(LHS.Val.sdiv_ov(RHS.Val, Overflow), false); 588 else 589 Res = LHS.Val / RHS.Val; 590 } else if (ValueLive) { 591 PP.Diag(OpLoc, diag::err_pp_division_by_zero) 592 << LHS.getRange() << RHS.getRange(); 593 return true; 594 } 595 break; 596 597 case tok::star: 598 if (Res.isSigned()) 599 Res = llvm::APSInt(LHS.Val.smul_ov(RHS.Val, Overflow), false); 600 else 601 Res = LHS.Val * RHS.Val; 602 break; 603 case tok::lessless: { 604 // Determine whether overflow is about to happen. 605 if (LHS.isUnsigned()) 606 Res = LHS.Val.ushl_ov(RHS.Val, Overflow); 607 else 608 Res = llvm::APSInt(LHS.Val.sshl_ov(RHS.Val, Overflow), false); 609 break; 610 } 611 case tok::greatergreater: { 612 // Determine whether overflow is about to happen. 613 unsigned ShAmt = static_cast<unsigned>(RHS.Val.getLimitedValue()); 614 if (ShAmt >= LHS.getBitWidth()) 615 Overflow = true, ShAmt = LHS.getBitWidth()-1; 616 Res = LHS.Val >> ShAmt; 617 break; 618 } 619 case tok::plus: 620 if (LHS.isUnsigned()) 621 Res = LHS.Val + RHS.Val; 622 else 623 Res = llvm::APSInt(LHS.Val.sadd_ov(RHS.Val, Overflow), false); 624 break; 625 case tok::minus: 626 if (LHS.isUnsigned()) 627 Res = LHS.Val - RHS.Val; 628 else 629 Res = llvm::APSInt(LHS.Val.ssub_ov(RHS.Val, Overflow), false); 630 break; 631 case tok::lessequal: 632 Res = LHS.Val <= RHS.Val; 633 Res.setIsUnsigned(false); // C99 6.5.8p6, result is always int (signed) 634 break; 635 case tok::less: 636 Res = LHS.Val < RHS.Val; 637 Res.setIsUnsigned(false); // C99 6.5.8p6, result is always int (signed) 638 break; 639 case tok::greaterequal: 640 Res = LHS.Val >= RHS.Val; 641 Res.setIsUnsigned(false); // C99 6.5.8p6, result is always int (signed) 642 break; 643 case tok::greater: 644 Res = LHS.Val > RHS.Val; 645 Res.setIsUnsigned(false); // C99 6.5.8p6, result is always int (signed) 646 break; 647 case tok::exclaimequal: 648 Res = LHS.Val != RHS.Val; 649 Res.setIsUnsigned(false); // C99 6.5.9p3, result is always int (signed) 650 break; 651 case tok::equalequal: 652 Res = LHS.Val == RHS.Val; 653 Res.setIsUnsigned(false); // C99 6.5.9p3, result is always int (signed) 654 break; 655 case tok::amp: 656 Res = LHS.Val & RHS.Val; 657 break; 658 case tok::caret: 659 Res = LHS.Val ^ RHS.Val; 660 break; 661 case tok::pipe: 662 Res = LHS.Val | RHS.Val; 663 break; 664 case tok::ampamp: 665 Res = (LHS.Val != 0 && RHS.Val != 0); 666 Res.setIsUnsigned(false); // C99 6.5.13p3, result is always int (signed) 667 break; 668 case tok::pipepipe: 669 Res = (LHS.Val != 0 || RHS.Val != 0); 670 Res.setIsUnsigned(false); // C99 6.5.14p3, result is always int (signed) 671 break; 672 case tok::comma: 673 // Comma is invalid in pp expressions in c89/c++ mode, but is valid in C99 674 // if not being evaluated. 675 if (!PP.getLangOpts().C99 || ValueLive) 676 PP.Diag(OpLoc, diag::ext_pp_comma_expr) 677 << LHS.getRange() << RHS.getRange(); 678 Res = RHS.Val; // LHS = LHS,RHS -> RHS. 679 break; 680 case tok::question: { 681 // Parse the : part of the expression. 682 if (PeekTok.isNot(tok::colon)) { 683 PP.Diag(PeekTok.getLocation(), diag::err_expected) 684 << tok::colon << LHS.getRange() << RHS.getRange(); 685 PP.Diag(OpLoc, diag::note_matching) << tok::question; 686 return true; 687 } 688 // Consume the :. 689 PP.LexNonComment(PeekTok); 690 691 // Evaluate the value after the :. 692 bool AfterColonLive = ValueLive && LHS.Val == 0; 693 PPValue AfterColonVal(LHS.getBitWidth()); 694 DefinedTracker DT; 695 if (EvaluateValue(AfterColonVal, PeekTok, DT, AfterColonLive, PP)) 696 return true; 697 698 // Parse anything after the : with the same precedence as ?. We allow 699 // things of equal precedence because ?: is right associative. 700 if (EvaluateDirectiveSubExpr(AfterColonVal, ThisPrec, 701 PeekTok, AfterColonLive, PP)) 702 return true; 703 704 // Now that we have the condition, the LHS and the RHS of the :, evaluate. 705 Res = LHS.Val != 0 ? RHS.Val : AfterColonVal.Val; 706 RHS.setEnd(AfterColonVal.getRange().getEnd()); 707 708 // Usual arithmetic conversions (C99 6.3.1.8p1): result is unsigned if 709 // either operand is unsigned. 710 Res.setIsUnsigned(RHS.isUnsigned() | AfterColonVal.isUnsigned()); 711 712 // Figure out the precedence of the token after the : part. 713 PeekPrec = getPrecedence(PeekTok.getKind()); 714 break; 715 } 716 case tok::colon: 717 // Don't allow :'s to float around without being part of ?: exprs. 718 PP.Diag(OpLoc, diag::err_pp_colon_without_question) 719 << LHS.getRange() << RHS.getRange(); 720 return true; 721 } 722 723 // If this operator is live and overflowed, report the issue. 724 if (Overflow && ValueLive) 725 PP.Diag(OpLoc, diag::warn_pp_expr_overflow) 726 << LHS.getRange() << RHS.getRange(); 727 728 // Put the result back into 'LHS' for our next iteration. 729 LHS.Val = Res; 730 LHS.setEnd(RHS.getRange().getEnd()); 731 } 732 } 733 734 /// EvaluateDirectiveExpression - Evaluate an integer constant expression that 735 /// may occur after a #if or #elif directive. If the expression is equivalent 736 /// to "!defined(X)" return X in IfNDefMacro. 737 bool Preprocessor:: 738 EvaluateDirectiveExpression(IdentifierInfo *&IfNDefMacro) { 739 SaveAndRestore<bool> PPDir(ParsingIfOrElifDirective, true); 740 // Save the current state of 'DisableMacroExpansion' and reset it to false. If 741 // 'DisableMacroExpansion' is true, then we must be in a macro argument list 742 // in which case a directive is undefined behavior. We want macros to be able 743 // to recursively expand in order to get more gcc-list behavior, so we force 744 // DisableMacroExpansion to false and restore it when we're done parsing the 745 // expression. 746 bool DisableMacroExpansionAtStartOfDirective = DisableMacroExpansion; 747 DisableMacroExpansion = false; 748 749 // Peek ahead one token. 750 Token Tok; 751 LexNonComment(Tok); 752 753 // C99 6.10.1p3 - All expressions are evaluated as intmax_t or uintmax_t. 754 unsigned BitWidth = getTargetInfo().getIntMaxTWidth(); 755 756 PPValue ResVal(BitWidth); 757 DefinedTracker DT; 758 if (EvaluateValue(ResVal, Tok, DT, true, *this)) { 759 // Parse error, skip the rest of the macro line. 760 if (Tok.isNot(tok::eod)) 761 DiscardUntilEndOfDirective(); 762 763 // Restore 'DisableMacroExpansion'. 764 DisableMacroExpansion = DisableMacroExpansionAtStartOfDirective; 765 return false; 766 } 767 768 // If we are at the end of the expression after just parsing a value, there 769 // must be no (unparenthesized) binary operators involved, so we can exit 770 // directly. 771 if (Tok.is(tok::eod)) { 772 // If the expression we parsed was of the form !defined(macro), return the 773 // macro in IfNDefMacro. 774 if (DT.State == DefinedTracker::NotDefinedMacro) 775 IfNDefMacro = DT.TheMacro; 776 777 // Restore 'DisableMacroExpansion'. 778 DisableMacroExpansion = DisableMacroExpansionAtStartOfDirective; 779 return ResVal.Val != 0; 780 } 781 782 // Otherwise, we must have a binary operator (e.g. "#if 1 < 2"), so parse the 783 // operator and the stuff after it. 784 if (EvaluateDirectiveSubExpr(ResVal, getPrecedence(tok::question), 785 Tok, true, *this)) { 786 // Parse error, skip the rest of the macro line. 787 if (Tok.isNot(tok::eod)) 788 DiscardUntilEndOfDirective(); 789 790 // Restore 'DisableMacroExpansion'. 791 DisableMacroExpansion = DisableMacroExpansionAtStartOfDirective; 792 return false; 793 } 794 795 // If we aren't at the tok::eod token, something bad happened, like an extra 796 // ')' token. 797 if (Tok.isNot(tok::eod)) { 798 Diag(Tok, diag::err_pp_expected_eol); 799 DiscardUntilEndOfDirective(); 800 } 801 802 // Restore 'DisableMacroExpansion'. 803 DisableMacroExpansion = DisableMacroExpansionAtStartOfDirective; 804 return ResVal.Val != 0; 805 } 806