PPExpressions.cpp revision 8ed3044a33679cbfa0617d465a50ec557d671ed7
166328480bb3eb6aa52e2c155657f3d19d4efea7aChris Lattner//===--- PPExpressions.cpp - Preprocessor Expression Evaluation -----------===// 2edf128a7fa90f2b0b7ee24741a04a7ae1ecd6f7eMisha Brukman// 366328480bb3eb6aa52e2c155657f3d19d4efea7aChris Lattner// The LLVM Compiler Infrastructure 466328480bb3eb6aa52e2c155657f3d19d4efea7aChris Lattner// 566328480bb3eb6aa52e2c155657f3d19d4efea7aChris Lattner// This file is distributed under the University of Illinois Open Source 666328480bb3eb6aa52e2c155657f3d19d4efea7aChris Lattner// License. See LICENSE.TXT for details. 7edf128a7fa90f2b0b7ee24741a04a7ae1ecd6f7eMisha Brukman// 866328480bb3eb6aa52e2c155657f3d19d4efea7aChris Lattner//===----------------------------------------------------------------------===// 966328480bb3eb6aa52e2c155657f3d19d4efea7aChris Lattner// 1066328480bb3eb6aa52e2c155657f3d19d4efea7aChris Lattner// This file implements the Preprocessor::EvaluateDirectiveExpression method, 1166328480bb3eb6aa52e2c155657f3d19d4efea7aChris Lattner// which parses and evaluates integer constant expressions for #if directives. 1266328480bb3eb6aa52e2c155657f3d19d4efea7aChris Lattner// 1366328480bb3eb6aa52e2c155657f3d19d4efea7aChris Lattner//===----------------------------------------------------------------------===// 1466328480bb3eb6aa52e2c155657f3d19d4efea7aChris Lattner// 1566328480bb3eb6aa52e2c155657f3d19d4efea7aChris Lattner// FIXME: implement testing for #assert's. 1666328480bb3eb6aa52e2c155657f3d19d4efea7aChris Lattner// 1766328480bb3eb6aa52e2c155657f3d19d4efea7aChris Lattner//===----------------------------------------------------------------------===// 18e9c44cdf18b1235841a5d8bfeb07bee9f5699b9aChris Lattner 1966328480bb3eb6aa52e2c155657f3d19d4efea7aChris Lattner#include "clang/Lex/Preprocessor.h" 2066328480bb3eb6aa52e2c155657f3d19d4efea7aChris Lattner#include "clang/Lex/MacroInfo.h" 2166328480bb3eb6aa52e2c155657f3d19d4efea7aChris Lattner#include "clang/Lex/LiteralSupport.h" 22e0646b86e3cdc35c5dd0e1c10b7ac564066e3bd6Chris Lattner#include "clang/Basic/TargetInfo.h" 23e0646b86e3cdc35c5dd0e1c10b7ac564066e3bd6Chris Lattner#include "clang/Basic/TokenKinds.h" 24e0646b86e3cdc35c5dd0e1c10b7ac564066e3bd6Chris Lattner#include "clang/Basic/Diagnostic.h" 25e0646b86e3cdc35c5dd0e1c10b7ac564066e3bd6Chris Lattner#include "llvm/ADT/APSInt.h" 26e0646b86e3cdc35c5dd0e1c10b7ac564066e3bd6Chris Lattner#include "llvm/ADT/SmallString.h" 27e0646b86e3cdc35c5dd0e1c10b7ac564066e3bd6Chris Lattnerusing namespace clang; 28e9c44cdf18b1235841a5d8bfeb07bee9f5699b9aChris Lattner 29e9c44cdf18b1235841a5d8bfeb07bee9f5699b9aChris Lattner/// PPValue - Represents the value of a subexpression of a preprocessor 30e9c44cdf18b1235841a5d8bfeb07bee9f5699b9aChris Lattner/// conditional and the source range covered by it. 31e0646b86e3cdc35c5dd0e1c10b7ac564066e3bd6Chris Lattnerclass PPValue { 32e0646b86e3cdc35c5dd0e1c10b7ac564066e3bd6Chris Lattner SourceRange Range; 33e9c44cdf18b1235841a5d8bfeb07bee9f5699b9aChris Lattnerpublic: 34e9c44cdf18b1235841a5d8bfeb07bee9f5699b9aChris Lattner llvm::APSInt Val; 35e0646b86e3cdc35c5dd0e1c10b7ac564066e3bd6Chris Lattner 36e0646b86e3cdc35c5dd0e1c10b7ac564066e3bd6Chris Lattner // Default ctor - Construct an 'invalid' PPValue. 37e0646b86e3cdc35c5dd0e1c10b7ac564066e3bd6Chris Lattner PPValue(unsigned BitWidth) : Val(BitWidth) {} 38fc08d9c789b6698fe5f5904d573bb03fcc52a32dChris Lattner 39fc08d9c789b6698fe5f5904d573bb03fcc52a32dChris Lattner unsigned getBitWidth() const { return Val.getBitWidth(); } 40fc08d9c789b6698fe5f5904d573bb03fcc52a32dChris Lattner bool isUnsigned() const { return Val.isUnsigned(); } 41fc08d9c789b6698fe5f5904d573bb03fcc52a32dChris Lattner 42fc08d9c789b6698fe5f5904d573bb03fcc52a32dChris Lattner const SourceRange &getRange() const { return Range; } 43fc08d9c789b6698fe5f5904d573bb03fcc52a32dChris Lattner 44e0646b86e3cdc35c5dd0e1c10b7ac564066e3bd6Chris Lattner void setRange(SourceLocation L) { Range.setBegin(L); Range.setEnd(L); } 45e0646b86e3cdc35c5dd0e1c10b7ac564066e3bd6Chris Lattner void setRange(SourceLocation B, SourceLocation E) { 46e0646b86e3cdc35c5dd0e1c10b7ac564066e3bd6Chris Lattner Range.setBegin(B); Range.setEnd(E); 47e9c44cdf18b1235841a5d8bfeb07bee9f5699b9aChris Lattner } 48e9c44cdf18b1235841a5d8bfeb07bee9f5699b9aChris Lattner void setBegin(SourceLocation L) { Range.setBegin(L); } 49e9c44cdf18b1235841a5d8bfeb07bee9f5699b9aChris Lattner void setEnd(SourceLocation L) { Range.setEnd(L); } 50c871e1d56fa9e4c73f01419d4f1fef6d47f24d29Chris Lattner}; 51c871e1d56fa9e4c73f01419d4f1fef6d47f24d29Chris Lattner 52c871e1d56fa9e4c73f01419d4f1fef6d47f24d29Chris Lattnerstatic bool EvaluateDirectiveSubExpr(PPValue &LHS, unsigned MinPrec, 53c871e1d56fa9e4c73f01419d4f1fef6d47f24d29Chris Lattner Token &PeekTok, bool ValueLive, 54c871e1d56fa9e4c73f01419d4f1fef6d47f24d29Chris Lattner Preprocessor &PP); 55c871e1d56fa9e4c73f01419d4f1fef6d47f24d29Chris Lattner 56c871e1d56fa9e4c73f01419d4f1fef6d47f24d29Chris Lattner/// DefinedTracker - This struct is used while parsing expressions to keep track 57c871e1d56fa9e4c73f01419d4f1fef6d47f24d29Chris Lattner/// of whether !defined(X) has been seen. 58c871e1d56fa9e4c73f01419d4f1fef6d47f24d29Chris Lattner/// 59c871e1d56fa9e4c73f01419d4f1fef6d47f24d29Chris Lattner/// With this simple scheme, we handle the basic forms: 60c871e1d56fa9e4c73f01419d4f1fef6d47f24d29Chris Lattner/// !defined(X) and !defined X 61c871e1d56fa9e4c73f01419d4f1fef6d47f24d29Chris Lattner/// but we also trivially handle (silly) stuff like: 62c871e1d56fa9e4c73f01419d4f1fef6d47f24d29Chris Lattner/// !!!defined(X) and +!defined(X) and !+!+!defined(X) and !(defined(X)). 63c871e1d56fa9e4c73f01419d4f1fef6d47f24d29Chris Lattnerstruct DefinedTracker { 64c871e1d56fa9e4c73f01419d4f1fef6d47f24d29Chris Lattner /// Each time a Value is evaluated, it returns information about whether the 65c871e1d56fa9e4c73f01419d4f1fef6d47f24d29Chris Lattner /// parsed value is of the form defined(X), !defined(X) or is something else. 66c871e1d56fa9e4c73f01419d4f1fef6d47f24d29Chris Lattner enum TrackerState { 67c871e1d56fa9e4c73f01419d4f1fef6d47f24d29Chris Lattner DefinedMacro, // defined(X) 68c871e1d56fa9e4c73f01419d4f1fef6d47f24d29Chris Lattner NotDefinedMacro, // !defined(X) 69e9c44cdf18b1235841a5d8bfeb07bee9f5699b9aChris Lattner Unknown // Something else. 70e9c44cdf18b1235841a5d8bfeb07bee9f5699b9aChris Lattner } State; 71e9c44cdf18b1235841a5d8bfeb07bee9f5699b9aChris Lattner /// TheMacro - When the state is DefinedMacro or NotDefinedMacro, this 72e9c44cdf18b1235841a5d8bfeb07bee9f5699b9aChris Lattner /// indicates the macro that was checked. 73edf128a7fa90f2b0b7ee24741a04a7ae1ecd6f7eMisha Brukman IdentifierInfo *TheMacro; 74e9c44cdf18b1235841a5d8bfeb07bee9f5699b9aChris Lattner}; 75e9c44cdf18b1235841a5d8bfeb07bee9f5699b9aChris Lattner 76e9c44cdf18b1235841a5d8bfeb07bee9f5699b9aChris Lattner/// EvaluateValue - Evaluate the token PeekTok (and any others needed) and 77e9c44cdf18b1235841a5d8bfeb07bee9f5699b9aChris Lattner/// return the computed value in Result. Return true if there was an error 78e9c44cdf18b1235841a5d8bfeb07bee9f5699b9aChris Lattner/// parsing. This function also returns information about the form of the 79e9c44cdf18b1235841a5d8bfeb07bee9f5699b9aChris Lattner/// expression in DT. See above for information on what DT means. 80e9c44cdf18b1235841a5d8bfeb07bee9f5699b9aChris Lattner/// 81edf128a7fa90f2b0b7ee24741a04a7ae1ecd6f7eMisha Brukman/// If ValueLive is false, then this value is being evaluated in a context where 82e9c44cdf18b1235841a5d8bfeb07bee9f5699b9aChris Lattner/// the result is not used. As such, avoid diagnostics that relate to 83e9c44cdf18b1235841a5d8bfeb07bee9f5699b9aChris Lattner/// evaluation. 84e9c44cdf18b1235841a5d8bfeb07bee9f5699b9aChris Lattnerstatic bool EvaluateValue(PPValue &Result, Token &PeekTok, DefinedTracker &DT, 85e9c44cdf18b1235841a5d8bfeb07bee9f5699b9aChris Lattner bool ValueLive, Preprocessor &PP) { 86e9c44cdf18b1235841a5d8bfeb07bee9f5699b9aChris Lattner DT.State = DefinedTracker::Unknown; 87e9c44cdf18b1235841a5d8bfeb07bee9f5699b9aChris Lattner 8818c2f13e0f9d0e5d6227cf6d1881e9ee3d1b6109Chris Lattner // If this token's spelling is a pp-identifier, check to see if it is 89e9c44cdf18b1235841a5d8bfeb07bee9f5699b9aChris Lattner // 'defined' or if it is a macro. Note that we check here because many 90e9c44cdf18b1235841a5d8bfeb07bee9f5699b9aChris Lattner // keywords are pp-identifiers, so we can't check the kind. 91e9c44cdf18b1235841a5d8bfeb07bee9f5699b9aChris Lattner if (IdentifierInfo *II = PeekTok.getIdentifierInfo()) { 92e9c44cdf18b1235841a5d8bfeb07bee9f5699b9aChris Lattner // If this identifier isn't 'defined' and it wasn't macro expanded, it turns 938a389bb37603fa99a980475a4f5cdc27fa4014f1Chris Lattner // into a simple 0, unless it is the C++ keyword "true", in which case it 944b7899343eb492b70868fc73450b708834a3cf99Chris Lattner // turns into "1". 95e9c44cdf18b1235841a5d8bfeb07bee9f5699b9aChris Lattner if (II->getPPKeywordID() != tok::pp_defined) { 96e9c44cdf18b1235841a5d8bfeb07bee9f5699b9aChris Lattner PP.Diag(PeekTok, diag::warn_pp_undef_identifier, II->getName()); 97e9c44cdf18b1235841a5d8bfeb07bee9f5699b9aChris Lattner Result.Val = II->getTokenID() == tok::kw_true; 98edf128a7fa90f2b0b7ee24741a04a7ae1ecd6f7eMisha Brukman Result.Val.setIsUnsigned(false); // "0" is signed intmax_t 0. 99e9c44cdf18b1235841a5d8bfeb07bee9f5699b9aChris Lattner Result.setRange(PeekTok.getLocation()); 10066328480bb3eb6aa52e2c155657f3d19d4efea7aChris Lattner PP.LexNonComment(PeekTok); 10166328480bb3eb6aa52e2c155657f3d19d4efea7aChris Lattner return false; 10266328480bb3eb6aa52e2c155657f3d19d4efea7aChris Lattner } 10366328480bb3eb6aa52e2c155657f3d19d4efea7aChris Lattner 10466328480bb3eb6aa52e2c155657f3d19d4efea7aChris Lattner // Handle "defined X" and "defined(X)". 10566328480bb3eb6aa52e2c155657f3d19d4efea7aChris Lattner Result.setBegin(PeekTok.getLocation()); 10666328480bb3eb6aa52e2c155657f3d19d4efea7aChris Lattner 10766328480bb3eb6aa52e2c155657f3d19d4efea7aChris Lattner // Get the next token, don't expand it. 10866328480bb3eb6aa52e2c155657f3d19d4efea7aChris Lattner PP.LexUnexpandedToken(PeekTok); 10966328480bb3eb6aa52e2c155657f3d19d4efea7aChris Lattner 11066328480bb3eb6aa52e2c155657f3d19d4efea7aChris Lattner // Two options, it can either be a pp-identifier or a (. 11166328480bb3eb6aa52e2c155657f3d19d4efea7aChris Lattner SourceLocation LParenLoc; 11266328480bb3eb6aa52e2c155657f3d19d4efea7aChris Lattner if (PeekTok.is(tok::l_paren)) { 11366328480bb3eb6aa52e2c155657f3d19d4efea7aChris Lattner // Found a paren, remember we saw it and skip it. 11466328480bb3eb6aa52e2c155657f3d19d4efea7aChris Lattner LParenLoc = PeekTok.getLocation(); 11566328480bb3eb6aa52e2c155657f3d19d4efea7aChris Lattner PP.LexUnexpandedToken(PeekTok); 11666328480bb3eb6aa52e2c155657f3d19d4efea7aChris Lattner } 11766328480bb3eb6aa52e2c155657f3d19d4efea7aChris Lattner 11866328480bb3eb6aa52e2c155657f3d19d4efea7aChris Lattner // If we don't have a pp-identifier now, this is an error. 11966328480bb3eb6aa52e2c155657f3d19d4efea7aChris Lattner if ((II = PeekTok.getIdentifierInfo()) == 0) { 12066328480bb3eb6aa52e2c155657f3d19d4efea7aChris Lattner PP.Diag(PeekTok, diag::err_pp_defined_requires_identifier); 12166328480bb3eb6aa52e2c155657f3d19d4efea7aChris Lattner return true; 12266328480bb3eb6aa52e2c155657f3d19d4efea7aChris Lattner } 12366328480bb3eb6aa52e2c155657f3d19d4efea7aChris Lattner 12466328480bb3eb6aa52e2c155657f3d19d4efea7aChris Lattner // Otherwise, we got an identifier, is it defined to something? 12566328480bb3eb6aa52e2c155657f3d19d4efea7aChris Lattner Result.Val = II->hasMacroDefinition(); 12666328480bb3eb6aa52e2c155657f3d19d4efea7aChris Lattner Result.Val.setIsUnsigned(false); // Result is signed intmax_t. 12766328480bb3eb6aa52e2c155657f3d19d4efea7aChris Lattner 128 // If there is a macro, mark it used. 129 if (Result.Val != 0 && ValueLive) { 130 MacroInfo *Macro = PP.getMacroInfo(II); 131 Macro->setIsUsed(true); 132 } 133 134 // Consume identifier. 135 Result.setEnd(PeekTok.getLocation()); 136 PP.LexNonComment(PeekTok); 137 138 // If we are in parens, ensure we have a trailing ). 139 if (LParenLoc.isValid()) { 140 if (PeekTok.isNot(tok::r_paren)) { 141 PP.Diag(PeekTok.getLocation(), diag::err_pp_missing_rparen); 142 PP.Diag(LParenLoc, diag::err_matching, "("); 143 return true; 144 } 145 // Consume the ). 146 Result.setEnd(PeekTok.getLocation()); 147 PP.LexNonComment(PeekTok); 148 } 149 150 // Success, remember that we saw defined(X). 151 DT.State = DefinedTracker::DefinedMacro; 152 DT.TheMacro = II; 153 return false; 154 } 155 156 switch (PeekTok.getKind()) { 157 default: // Non-value token. 158 PP.Diag(PeekTok, diag::err_pp_expr_bad_token_start_expr); 159 return true; 160 case tok::eom: 161 case tok::r_paren: 162 // If there is no expression, report and exit. 163 PP.Diag(PeekTok, diag::err_pp_expected_value_in_expr); 164 return true; 165 case tok::numeric_constant: { 166 llvm::SmallString<64> IntegerBuffer; 167 IntegerBuffer.resize(PeekTok.getLength()); 168 const char *ThisTokBegin = &IntegerBuffer[0]; 169 unsigned ActualLength = PP.getSpelling(PeekTok, ThisTokBegin); 170 NumericLiteralParser Literal(ThisTokBegin, ThisTokBegin+ActualLength, 171 PeekTok.getLocation(), PP); 172 if (Literal.hadError) 173 return true; // a diagnostic was already reported. 174 175 if (Literal.isFloatingLiteral() || Literal.isImaginary) { 176 PP.Diag(PeekTok, diag::err_pp_illegal_floating_literal); 177 return true; 178 } 179 assert(Literal.isIntegerLiteral() && "Unknown ppnumber"); 180 181 // long long is a C99 feature. 182 if (!PP.getLangOptions().C99 && !PP.getLangOptions().CPlusPlus0x 183 && Literal.isLongLong) 184 PP.Diag(PeekTok, diag::ext_longlong); 185 186 // Parse the integer literal into Result. 187 if (Literal.GetIntegerValue(Result.Val)) { 188 // Overflow parsing integer literal. 189 if (ValueLive) PP.Diag(PeekTok, diag::warn_integer_too_large); 190 Result.Val.setIsUnsigned(true); 191 } else { 192 // Set the signedness of the result to match whether there was a U suffix 193 // or not. 194 Result.Val.setIsUnsigned(Literal.isUnsigned); 195 196 // Detect overflow based on whether the value is signed. If signed 197 // and if the value is too large, emit a warning "integer constant is so 198 // large that it is unsigned" e.g. on 12345678901234567890 where intmax_t 199 // is 64-bits. 200 if (!Literal.isUnsigned && Result.Val.isNegative()) { 201 if (ValueLive) 202 PP.Diag(PeekTok, diag::warn_integer_too_large_for_signed); 203 Result.Val.setIsUnsigned(true); 204 } 205 } 206 207 // Consume the token. 208 Result.setRange(PeekTok.getLocation()); 209 PP.LexNonComment(PeekTok); 210 return false; 211 } 212 case tok::char_constant: { // 'x' 213 llvm::SmallString<32> CharBuffer; 214 CharBuffer.resize(PeekTok.getLength()); 215 const char *ThisTokBegin = &CharBuffer[0]; 216 unsigned ActualLength = PP.getSpelling(PeekTok, ThisTokBegin); 217 CharLiteralParser Literal(ThisTokBegin, ThisTokBegin+ActualLength, 218 PeekTok.getLocation(), PP); 219 if (Literal.hadError()) 220 return true; // A diagnostic was already emitted. 221 222 // Character literals are always int or wchar_t, expand to intmax_t. 223 TargetInfo &TI = PP.getTargetInfo(); 224 unsigned NumBits = TI.getCharWidth(Literal.isWide()); 225 226 // Set the width. 227 llvm::APSInt Val(NumBits); 228 // Set the value. 229 Val = Literal.getValue(); 230 // Set the signedness. 231 Val.setIsUnsigned(!TI.isCharSigned()); 232 233 if (Result.Val.getBitWidth() > Val.getBitWidth()) { 234 Result.Val = Val.extend(Result.Val.getBitWidth()); 235 } else { 236 assert(Result.Val.getBitWidth() == Val.getBitWidth() && 237 "intmax_t smaller than char/wchar_t?"); 238 Result.Val = Val; 239 } 240 241 // Consume the token. 242 Result.setRange(PeekTok.getLocation()); 243 PP.LexNonComment(PeekTok); 244 return false; 245 } 246 case tok::l_paren: { 247 SourceLocation Start = PeekTok.getLocation(); 248 PP.LexNonComment(PeekTok); // Eat the (. 249 // Parse the value and if there are any binary operators involved, parse 250 // them. 251 if (EvaluateValue(Result, PeekTok, DT, ValueLive, PP)) return true; 252 253 // If this is a silly value like (X), which doesn't need parens, check for 254 // !(defined X). 255 if (PeekTok.is(tok::r_paren)) { 256 // Just use DT unmodified as our result. 257 } else { 258 // Otherwise, we have something like (x+y), and we consumed '(x'. 259 if (EvaluateDirectiveSubExpr(Result, 1, PeekTok, ValueLive, PP)) 260 return true; 261 262 if (PeekTok.isNot(tok::r_paren)) { 263 PP.Diag(PeekTok.getLocation(), diag::err_pp_expected_rparen, 264 Result.getRange()); 265 PP.Diag(Start, diag::err_matching, "("); 266 return true; 267 } 268 DT.State = DefinedTracker::Unknown; 269 } 270 Result.setRange(Start, PeekTok.getLocation()); 271 PP.LexNonComment(PeekTok); // Eat the ). 272 return false; 273 } 274 case tok::plus: { 275 SourceLocation Start = PeekTok.getLocation(); 276 // Unary plus doesn't modify the value. 277 PP.LexNonComment(PeekTok); 278 if (EvaluateValue(Result, PeekTok, DT, ValueLive, PP)) return true; 279 Result.setBegin(Start); 280 return false; 281 } 282 case tok::minus: { 283 SourceLocation Loc = PeekTok.getLocation(); 284 PP.LexNonComment(PeekTok); 285 if (EvaluateValue(Result, PeekTok, DT, ValueLive, PP)) return true; 286 Result.setBegin(Loc); 287 288 // C99 6.5.3.3p3: The sign of the result matches the sign of the operand. 289 Result.Val = -Result.Val; 290 291 bool Overflow = false; 292 if (Result.isUnsigned()) 293 Overflow = Result.Val.isNegative(); 294 else if (Result.Val.isMinSignedValue()) 295 Overflow = true; // -MININT is the only thing that overflows. 296 297 // If this operator is live and overflowed, report the issue. 298 if (Overflow && ValueLive) 299 PP.Diag(Loc, diag::warn_pp_expr_overflow, Result.getRange()); 300 301 DT.State = DefinedTracker::Unknown; 302 return false; 303 } 304 305 case tok::tilde: { 306 SourceLocation Start = PeekTok.getLocation(); 307 PP.LexNonComment(PeekTok); 308 if (EvaluateValue(Result, PeekTok, DT, ValueLive, PP)) return true; 309 Result.setBegin(Start); 310 311 // C99 6.5.3.3p4: The sign of the result matches the sign of the operand. 312 Result.Val = ~Result.Val; 313 DT.State = DefinedTracker::Unknown; 314 return false; 315 } 316 317 case tok::exclaim: { 318 SourceLocation Start = PeekTok.getLocation(); 319 PP.LexNonComment(PeekTok); 320 if (EvaluateValue(Result, PeekTok, DT, ValueLive, PP)) return true; 321 Result.setBegin(Start); 322 Result.Val = !Result.Val; 323 // C99 6.5.3.3p5: The sign of the result is 'int', aka it is signed. 324 Result.Val.setIsUnsigned(false); 325 326 if (DT.State == DefinedTracker::DefinedMacro) 327 DT.State = DefinedTracker::NotDefinedMacro; 328 else if (DT.State == DefinedTracker::NotDefinedMacro) 329 DT.State = DefinedTracker::DefinedMacro; 330 return false; 331 } 332 333 // FIXME: Handle #assert 334 } 335} 336 337 338 339/// getPrecedence - Return the precedence of the specified binary operator 340/// token. This returns: 341/// ~0 - Invalid token. 342/// 14 -> 3 - various operators. 343/// 0 - 'eom' or ')' 344static unsigned getPrecedence(tok::TokenKind Kind) { 345 switch (Kind) { 346 default: return ~0U; 347 case tok::percent: 348 case tok::slash: 349 case tok::star: return 14; 350 case tok::plus: 351 case tok::minus: return 13; 352 case tok::lessless: 353 case tok::greatergreater: return 12; 354 case tok::lessequal: 355 case tok::less: 356 case tok::greaterequal: 357 case tok::greater: return 11; 358 case tok::exclaimequal: 359 case tok::equalequal: return 10; 360 case tok::amp: return 9; 361 case tok::caret: return 8; 362 case tok::pipe: return 7; 363 case tok::ampamp: return 6; 364 case tok::pipepipe: return 5; 365 case tok::comma: return 4; 366 case tok::question: return 3; 367 case tok::colon: return 2; 368 case tok::r_paren: return 0; // Lowest priority, end of expr. 369 case tok::eom: return 0; // Lowest priority, end of macro. 370 } 371} 372 373 374/// EvaluateDirectiveSubExpr - Evaluate the subexpression whose first token is 375/// PeekTok, and whose precedence is PeekPrec. This returns the result in LHS. 376/// 377/// If ValueLive is false, then this value is being evaluated in a context where 378/// the result is not used. As such, avoid diagnostics that relate to 379/// evaluation, such as division by zero warnings. 380static bool EvaluateDirectiveSubExpr(PPValue &LHS, unsigned MinPrec, 381 Token &PeekTok, bool ValueLive, 382 Preprocessor &PP) { 383 unsigned PeekPrec = getPrecedence(PeekTok.getKind()); 384 // If this token isn't valid, report the error. 385 if (PeekPrec == ~0U) { 386 PP.Diag(PeekTok.getLocation(), diag::err_pp_expr_bad_token_binop, 387 LHS.getRange()); 388 return true; 389 } 390 391 while (1) { 392 // If this token has a lower precedence than we are allowed to parse, return 393 // it so that higher levels of the recursion can parse it. 394 if (PeekPrec < MinPrec) 395 return false; 396 397 tok::TokenKind Operator = PeekTok.getKind(); 398 399 // If this is a short-circuiting operator, see if the RHS of the operator is 400 // dead. Note that this cannot just clobber ValueLive. Consider 401 // "0 && 1 ? 4 : 1 / 0", which is parsed as "(0 && 1) ? 4 : (1 / 0)". In 402 // this example, the RHS of the && being dead does not make the rest of the 403 // expr dead. 404 bool RHSIsLive; 405 if (Operator == tok::ampamp && LHS.Val == 0) 406 RHSIsLive = false; // RHS of "0 && x" is dead. 407 else if (Operator == tok::pipepipe && LHS.Val != 0) 408 RHSIsLive = false; // RHS of "1 || x" is dead. 409 else if (Operator == tok::question && LHS.Val == 0) 410 RHSIsLive = false; // RHS (x) of "0 ? x : y" is dead. 411 else 412 RHSIsLive = ValueLive; 413 414 // Consume the operator, remembering the operator's location for reporting. 415 SourceLocation OpLoc = PeekTok.getLocation(); 416 PP.LexNonComment(PeekTok); 417 418 PPValue RHS(LHS.getBitWidth()); 419 // Parse the RHS of the operator. 420 DefinedTracker DT; 421 if (EvaluateValue(RHS, PeekTok, DT, RHSIsLive, PP)) return true; 422 423 // Remember the precedence of this operator and get the precedence of the 424 // operator immediately to the right of the RHS. 425 unsigned ThisPrec = PeekPrec; 426 PeekPrec = getPrecedence(PeekTok.getKind()); 427 428 // If this token isn't valid, report the error. 429 if (PeekPrec == ~0U) { 430 PP.Diag(PeekTok.getLocation(), diag::err_pp_expr_bad_token_binop, 431 RHS.getRange()); 432 return true; 433 } 434 435 bool isRightAssoc = Operator == tok::question; 436 437 // Get the precedence of the operator to the right of the RHS. If it binds 438 // more tightly with RHS than we do, evaluate it completely first. 439 if (ThisPrec < PeekPrec || 440 (ThisPrec == PeekPrec && isRightAssoc)) { 441 if (EvaluateDirectiveSubExpr(RHS, ThisPrec+!isRightAssoc, 442 PeekTok, RHSIsLive, PP)) 443 return true; 444 PeekPrec = getPrecedence(PeekTok.getKind()); 445 } 446 assert(PeekPrec <= ThisPrec && "Recursion didn't work!"); 447 448 // Usual arithmetic conversions (C99 6.3.1.8p1): result is unsigned if 449 // either operand is unsigned. 450 llvm::APSInt Res(LHS.getBitWidth()); 451 switch (Operator) { 452 case tok::question: // No UAC for x and y in "x ? y : z". 453 case tok::lessless: // Shift amount doesn't UAC with shift value. 454 case tok::greatergreater: // Shift amount doesn't UAC with shift value. 455 case tok::comma: // Comma operands are not subject to UACs. 456 case tok::pipepipe: // Logical || does not do UACs. 457 case tok::ampamp: // Logical && does not do UACs. 458 break; // No UAC 459 default: 460 Res.setIsUnsigned(LHS.isUnsigned()|RHS.isUnsigned()); 461 // If this just promoted something from signed to unsigned, and if the 462 // value was negative, warn about it. 463 if (ValueLive && Res.isUnsigned()) { 464 if (!LHS.isUnsigned() && LHS.Val.isNegative()) 465 PP.Diag(OpLoc, diag::warn_pp_convert_lhs_to_positive, 466 LHS.Val.toStringSigned() + " to "+LHS.Val.toStringUnsigned(), 467 LHS.getRange(), RHS.getRange()); 468 if (!RHS.isUnsigned() && RHS.Val.isNegative()) 469 PP.Diag(OpLoc, diag::warn_pp_convert_rhs_to_positive, 470 RHS.Val.toStringSigned() + " to "+RHS.Val.toStringUnsigned(), 471 LHS.getRange(), RHS.getRange()); 472 } 473 LHS.Val.setIsUnsigned(Res.isUnsigned()); 474 RHS.Val.setIsUnsigned(Res.isUnsigned()); 475 } 476 477 // FIXME: All of these should detect and report overflow?? 478 bool Overflow = false; 479 switch (Operator) { 480 default: assert(0 && "Unknown operator token!"); 481 case tok::percent: 482 if (RHS.Val != 0) 483 Res = LHS.Val % RHS.Val; 484 else if (ValueLive) { 485 PP.Diag(OpLoc, diag::err_pp_remainder_by_zero, LHS.getRange(), 486 RHS.getRange()); 487 return true; 488 } 489 break; 490 case tok::slash: 491 if (RHS.Val != 0) { 492 Res = LHS.Val / RHS.Val; 493 if (LHS.Val.isSigned()) // MININT/-1 --> overflow. 494 Overflow = LHS.Val.isMinSignedValue() && RHS.Val.isAllOnesValue(); 495 } else if (ValueLive) { 496 PP.Diag(OpLoc, diag::err_pp_division_by_zero, LHS.getRange(), 497 RHS.getRange()); 498 return true; 499 } 500 break; 501 502 case tok::star: 503 Res = LHS.Val * RHS.Val; 504 if (LHS.Val != 0 && RHS.Val != 0) 505 Overflow = Res/RHS.Val != LHS.Val || Res/LHS.Val != RHS.Val; 506 break; 507 case tok::lessless: { 508 // Determine whether overflow is about to happen. 509 unsigned ShAmt = static_cast<unsigned>(RHS.Val.getLimitedValue()); 510 if (ShAmt >= LHS.Val.getBitWidth()) 511 Overflow = true, ShAmt = LHS.Val.getBitWidth()-1; 512 else if (LHS.isUnsigned()) 513 Overflow = ShAmt > LHS.Val.countLeadingZeros(); 514 else if (LHS.Val.isNonNegative()) // Don't allow sign change. 515 Overflow = ShAmt >= LHS.Val.countLeadingZeros(); 516 else 517 Overflow = ShAmt >= LHS.Val.countLeadingOnes(); 518 519 Res = LHS.Val << ShAmt; 520 break; 521 } 522 case tok::greatergreater: { 523 // Determine whether overflow is about to happen. 524 unsigned ShAmt = static_cast<unsigned>(RHS.Val.getLimitedValue()); 525 if (ShAmt >= LHS.getBitWidth()) 526 Overflow = true, ShAmt = LHS.getBitWidth()-1; 527 Res = LHS.Val >> ShAmt; 528 break; 529 } 530 case tok::plus: 531 Res = LHS.Val + RHS.Val; 532 if (LHS.isUnsigned()) 533 Overflow = Res.ult(LHS.Val); 534 else if (LHS.Val.isNonNegative() == RHS.Val.isNonNegative() && 535 Res.isNonNegative() != LHS.Val.isNonNegative()) 536 Overflow = true; // Overflow for signed addition. 537 break; 538 case tok::minus: 539 Res = LHS.Val - RHS.Val; 540 if (LHS.isUnsigned()) 541 Overflow = Res.ugt(LHS.Val); 542 else if (LHS.Val.isNonNegative() != RHS.Val.isNonNegative() && 543 Res.isNonNegative() != LHS.Val.isNonNegative()) 544 Overflow = true; // Overflow for signed subtraction. 545 break; 546 case tok::lessequal: 547 Res = LHS.Val <= RHS.Val; 548 Res.setIsUnsigned(false); // C99 6.5.8p6, result is always int (signed) 549 break; 550 case tok::less: 551 Res = LHS.Val < RHS.Val; 552 Res.setIsUnsigned(false); // C99 6.5.8p6, result is always int (signed) 553 break; 554 case tok::greaterequal: 555 Res = LHS.Val >= RHS.Val; 556 Res.setIsUnsigned(false); // C99 6.5.8p6, result is always int (signed) 557 break; 558 case tok::greater: 559 Res = LHS.Val > RHS.Val; 560 Res.setIsUnsigned(false); // C99 6.5.8p6, result is always int (signed) 561 break; 562 case tok::exclaimequal: 563 Res = LHS.Val != RHS.Val; 564 Res.setIsUnsigned(false); // C99 6.5.9p3, result is always int (signed) 565 break; 566 case tok::equalequal: 567 Res = LHS.Val == RHS.Val; 568 Res.setIsUnsigned(false); // C99 6.5.9p3, result is always int (signed) 569 break; 570 case tok::amp: 571 Res = LHS.Val & RHS.Val; 572 break; 573 case tok::caret: 574 Res = LHS.Val ^ RHS.Val; 575 break; 576 case tok::pipe: 577 Res = LHS.Val | RHS.Val; 578 break; 579 case tok::ampamp: 580 Res = (LHS.Val != 0 && RHS.Val != 0); 581 Res.setIsUnsigned(false); // C99 6.5.13p3, result is always int (signed) 582 break; 583 case tok::pipepipe: 584 Res = (LHS.Val != 0 || RHS.Val != 0); 585 Res.setIsUnsigned(false); // C99 6.5.14p3, result is always int (signed) 586 break; 587 case tok::comma: 588 // Comma is invalid in pp expressions in c89/c++ mode, but is valid in C99 589 // if not being evaluated. 590 if (!PP.getLangOptions().C99 || ValueLive) 591 PP.Diag(OpLoc, diag::ext_pp_comma_expr, LHS.getRange(), RHS.getRange()); 592 Res = RHS.Val; // LHS = LHS,RHS -> RHS. 593 break; 594 case tok::question: { 595 // Parse the : part of the expression. 596 if (PeekTok.isNot(tok::colon)) { 597 PP.Diag(PeekTok.getLocation(), diag::err_expected_colon, 598 LHS.getRange(), RHS.getRange()); 599 PP.Diag(OpLoc, diag::err_matching, "?"); 600 return true; 601 } 602 // Consume the :. 603 PP.LexNonComment(PeekTok); 604 605 // Evaluate the value after the :. 606 bool AfterColonLive = ValueLive && LHS.Val == 0; 607 PPValue AfterColonVal(LHS.getBitWidth()); 608 DefinedTracker DT; 609 if (EvaluateValue(AfterColonVal, PeekTok, DT, AfterColonLive, PP)) 610 return true; 611 612 // Parse anything after the : RHS that has a higher precedence than ?. 613 if (EvaluateDirectiveSubExpr(AfterColonVal, ThisPrec+1, 614 PeekTok, AfterColonLive, PP)) 615 return true; 616 617 // Now that we have the condition, the LHS and the RHS of the :, evaluate. 618 Res = LHS.Val != 0 ? RHS.Val : AfterColonVal.Val; 619 RHS.setEnd(AfterColonVal.getRange().getEnd()); 620 621 // Usual arithmetic conversions (C99 6.3.1.8p1): result is unsigned if 622 // either operand is unsigned. 623 Res.setIsUnsigned(RHS.isUnsigned() | AfterColonVal.isUnsigned()); 624 625 // Figure out the precedence of the token after the : part. 626 PeekPrec = getPrecedence(PeekTok.getKind()); 627 break; 628 } 629 case tok::colon: 630 // Don't allow :'s to float around without being part of ?: exprs. 631 PP.Diag(OpLoc, diag::err_pp_colon_without_question, LHS.getRange(), 632 RHS.getRange()); 633 return true; 634 } 635 636 // If this operator is live and overflowed, report the issue. 637 if (Overflow && ValueLive) 638 PP.Diag(OpLoc, diag::warn_pp_expr_overflow, 639 LHS.getRange(), RHS.getRange()); 640 641 // Put the result back into 'LHS' for our next iteration. 642 LHS.Val = Res; 643 LHS.setEnd(RHS.getRange().getEnd()); 644 } 645 646 return false; 647} 648 649/// EvaluateDirectiveExpression - Evaluate an integer constant expression that 650/// may occur after a #if or #elif directive. If the expression is equivalent 651/// to "!defined(X)" return X in IfNDefMacro. 652bool Preprocessor:: 653EvaluateDirectiveExpression(IdentifierInfo *&IfNDefMacro) { 654 // Peek ahead one token. 655 Token Tok; 656 Lex(Tok); 657 658 // C99 6.10.1p3 - All expressions are evaluated as intmax_t or uintmax_t. 659 unsigned BitWidth = getTargetInfo().getIntMaxTWidth(); 660 661 PPValue ResVal(BitWidth); 662 DefinedTracker DT; 663 if (EvaluateValue(ResVal, Tok, DT, true, *this)) { 664 // Parse error, skip the rest of the macro line. 665 if (Tok.isNot(tok::eom)) 666 DiscardUntilEndOfDirective(); 667 return false; 668 } 669 670 // If we are at the end of the expression after just parsing a value, there 671 // must be no (unparenthesized) binary operators involved, so we can exit 672 // directly. 673 if (Tok.is(tok::eom)) { 674 // If the expression we parsed was of the form !defined(macro), return the 675 // macro in IfNDefMacro. 676 if (DT.State == DefinedTracker::NotDefinedMacro) 677 IfNDefMacro = DT.TheMacro; 678 679 return ResVal.Val != 0; 680 } 681 682 // Otherwise, we must have a binary operator (e.g. "#if 1 < 2"), so parse the 683 // operator and the stuff after it. 684 if (EvaluateDirectiveSubExpr(ResVal, 1, Tok, true, *this)) { 685 // Parse error, skip the rest of the macro line. 686 if (Tok.isNot(tok::eom)) 687 DiscardUntilEndOfDirective(); 688 return false; 689 } 690 691 // If we aren't at the tok::eom token, something bad happened, like an extra 692 // ')' token. 693 if (Tok.isNot(tok::eom)) { 694 Diag(Tok, diag::err_pp_expected_eol); 695 DiscardUntilEndOfDirective(); 696 } 697 698 return ResVal.Val != 0; 699} 700 701