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