MacroArgs.cpp revision 327952
1//===--- MacroArgs.cpp - Formal argument info for Macros ------------------===// 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 MacroArgs interface. 11// 12//===----------------------------------------------------------------------===// 13 14#include "clang/Lex/MacroArgs.h" 15#include "clang/Lex/LexDiagnostic.h" 16#include "clang/Lex/MacroInfo.h" 17#include "clang/Lex/Preprocessor.h" 18#include "llvm/ADT/SmallString.h" 19#include "llvm/Support/SaveAndRestore.h" 20#include <algorithm> 21 22using namespace clang; 23 24/// MacroArgs ctor function - This destroys the vector passed in. 25MacroArgs *MacroArgs::create(const MacroInfo *MI, 26 ArrayRef<Token> UnexpArgTokens, 27 bool VarargsElided, Preprocessor &PP) { 28 assert(MI->isFunctionLike() && 29 "Can't have args for an object-like macro!"); 30 MacroArgs **ResultEnt = nullptr; 31 unsigned ClosestMatch = ~0U; 32 33 // See if we have an entry with a big enough argument list to reuse on the 34 // free list. If so, reuse it. 35 for (MacroArgs **Entry = &PP.MacroArgCache; *Entry; 36 Entry = &(*Entry)->ArgCache) { 37 if ((*Entry)->NumUnexpArgTokens >= UnexpArgTokens.size() && 38 (*Entry)->NumUnexpArgTokens < ClosestMatch) { 39 ResultEnt = Entry; 40 41 // If we have an exact match, use it. 42 if ((*Entry)->NumUnexpArgTokens == UnexpArgTokens.size()) 43 break; 44 // Otherwise, use the best fit. 45 ClosestMatch = (*Entry)->NumUnexpArgTokens; 46 } 47 } 48 MacroArgs *Result; 49 if (!ResultEnt) { 50 // Allocate memory for a MacroArgs object with the lexer tokens at the end, 51 // and construct the MacroArgs object. 52 Result = new (std::malloc(totalSizeToAlloc<Token>(UnexpArgTokens.size()))) 53 MacroArgs(UnexpArgTokens.size(), VarargsElided, MI->getNumParams()); 54 } else { 55 Result = *ResultEnt; 56 // Unlink this node from the preprocessors singly linked list. 57 *ResultEnt = Result->ArgCache; 58 Result->NumUnexpArgTokens = UnexpArgTokens.size(); 59 Result->VarargsElided = VarargsElided; 60 Result->NumMacroArgs = MI->getNumParams(); 61 } 62 63 // Copy the actual unexpanded tokens to immediately after the result ptr. 64 if (!UnexpArgTokens.empty()) { 65 static_assert(std::is_trivial<Token>::value, 66 "assume trivial copyability if copying into the " 67 "uninitialized array (as opposed to reusing a cached " 68 "MacroArgs)"); 69 std::copy(UnexpArgTokens.begin(), UnexpArgTokens.end(), 70 Result->getTrailingObjects<Token>()); 71 } 72 73 return Result; 74} 75 76/// destroy - Destroy and deallocate the memory for this object. 77/// 78void MacroArgs::destroy(Preprocessor &PP) { 79 StringifiedArgs.clear(); 80 81 // Don't clear PreExpArgTokens, just clear the entries. Clearing the entries 82 // would deallocate the element vectors. 83 for (unsigned i = 0, e = PreExpArgTokens.size(); i != e; ++i) 84 PreExpArgTokens[i].clear(); 85 86 // Add this to the preprocessor's free list. 87 ArgCache = PP.MacroArgCache; 88 PP.MacroArgCache = this; 89} 90 91/// deallocate - This should only be called by the Preprocessor when managing 92/// its freelist. 93MacroArgs *MacroArgs::deallocate() { 94 MacroArgs *Next = ArgCache; 95 96 // Run the dtor to deallocate the vectors. 97 this->~MacroArgs(); 98 // Release the memory for the object. 99 static_assert(std::is_trivially_destructible<Token>::value, 100 "assume trivially destructible and forego destructors"); 101 free(this); 102 103 return Next; 104} 105 106 107/// getArgLength - Given a pointer to an expanded or unexpanded argument, 108/// return the number of tokens, not counting the EOF, that make up the 109/// argument. 110unsigned MacroArgs::getArgLength(const Token *ArgPtr) { 111 unsigned NumArgTokens = 0; 112 for (; ArgPtr->isNot(tok::eof); ++ArgPtr) 113 ++NumArgTokens; 114 return NumArgTokens; 115} 116 117 118/// getUnexpArgument - Return the unexpanded tokens for the specified formal. 119/// 120const Token *MacroArgs::getUnexpArgument(unsigned Arg) const { 121 122 assert(Arg < getNumMacroArguments() && "Invalid arg #"); 123 // The unexpanded argument tokens start immediately after the MacroArgs object 124 // in memory. 125 const Token *Start = getTrailingObjects<Token>(); 126 const Token *Result = Start; 127 128 // Scan to find Arg. 129 for (; Arg; ++Result) { 130 assert(Result < Start+NumUnexpArgTokens && "Invalid arg #"); 131 if (Result->is(tok::eof)) 132 --Arg; 133 } 134 assert(Result < Start+NumUnexpArgTokens && "Invalid arg #"); 135 return Result; 136} 137 138// This function assumes that the variadic arguments are the tokens 139// corresponding to the last parameter (ellipsis) - and since tokens are 140// separated by the 'eof' token, if that is the only token corresponding to that 141// last parameter, we know no variadic arguments were supplied. 142bool MacroArgs::invokedWithVariadicArgument(const MacroInfo *const MI) const { 143 if (!MI->isVariadic()) 144 return false; 145 const int VariadicArgIndex = getNumMacroArguments() - 1; 146 return getUnexpArgument(VariadicArgIndex)->isNot(tok::eof); 147} 148 149/// ArgNeedsPreexpansion - If we can prove that the argument won't be affected 150/// by pre-expansion, return false. Otherwise, conservatively return true. 151bool MacroArgs::ArgNeedsPreexpansion(const Token *ArgTok, 152 Preprocessor &PP) const { 153 // If there are no identifiers in the argument list, or if the identifiers are 154 // known to not be macros, pre-expansion won't modify it. 155 for (; ArgTok->isNot(tok::eof); ++ArgTok) 156 if (IdentifierInfo *II = ArgTok->getIdentifierInfo()) 157 if (II->hasMacroDefinition()) 158 // Return true even though the macro could be a function-like macro 159 // without a following '(' token, or could be disabled, or not visible. 160 return true; 161 return false; 162} 163 164/// getPreExpArgument - Return the pre-expanded form of the specified 165/// argument. 166const std::vector<Token> &MacroArgs::getPreExpArgument(unsigned Arg, 167 Preprocessor &PP) { 168 assert(Arg < getNumMacroArguments() && "Invalid argument number!"); 169 170 // If we have already computed this, return it. 171 if (PreExpArgTokens.size() < getNumMacroArguments()) 172 PreExpArgTokens.resize(getNumMacroArguments()); 173 174 std::vector<Token> &Result = PreExpArgTokens[Arg]; 175 if (!Result.empty()) return Result; 176 177 SaveAndRestore<bool> PreExpandingMacroArgs(PP.InMacroArgPreExpansion, true); 178 179 const Token *AT = getUnexpArgument(Arg); 180 unsigned NumToks = getArgLength(AT)+1; // Include the EOF. 181 182 // Otherwise, we have to pre-expand this argument, populating Result. To do 183 // this, we set up a fake TokenLexer to lex from the unexpanded argument 184 // list. With this installed, we lex expanded tokens until we hit the EOF 185 // token at the end of the unexp list. 186 PP.EnterTokenStream(AT, NumToks, false /*disable expand*/, 187 false /*owns tokens*/); 188 189 // Lex all of the macro-expanded tokens into Result. 190 do { 191 Result.push_back(Token()); 192 Token &Tok = Result.back(); 193 PP.Lex(Tok); 194 } while (Result.back().isNot(tok::eof)); 195 196 // Pop the token stream off the top of the stack. We know that the internal 197 // pointer inside of it is to the "end" of the token stream, but the stack 198 // will not otherwise be popped until the next token is lexed. The problem is 199 // that the token may be lexed sometime after the vector of tokens itself is 200 // destroyed, which would be badness. 201 if (PP.InCachingLexMode()) 202 PP.ExitCachingLexMode(); 203 PP.RemoveTopOfLexerStack(); 204 return Result; 205} 206 207 208/// StringifyArgument - Implement C99 6.10.3.2p2, converting a sequence of 209/// tokens into the literal string token that should be produced by the C # 210/// preprocessor operator. If Charify is true, then it should be turned into 211/// a character literal for the Microsoft charize (#@) extension. 212/// 213Token MacroArgs::StringifyArgument(const Token *ArgToks, 214 Preprocessor &PP, bool Charify, 215 SourceLocation ExpansionLocStart, 216 SourceLocation ExpansionLocEnd) { 217 Token Tok; 218 Tok.startToken(); 219 Tok.setKind(Charify ? tok::char_constant : tok::string_literal); 220 221 const Token *ArgTokStart = ArgToks; 222 223 // Stringify all the tokens. 224 SmallString<128> Result; 225 Result += "\""; 226 227 bool isFirst = true; 228 for (; ArgToks->isNot(tok::eof); ++ArgToks) { 229 const Token &Tok = *ArgToks; 230 if (!isFirst && (Tok.hasLeadingSpace() || Tok.isAtStartOfLine())) 231 Result += ' '; 232 isFirst = false; 233 234 // If this is a string or character constant, escape the token as specified 235 // by 6.10.3.2p2. 236 if (tok::isStringLiteral(Tok.getKind()) || // "foo", u8R"x(foo)x"_bar, etc. 237 Tok.is(tok::char_constant) || // 'x' 238 Tok.is(tok::wide_char_constant) || // L'x'. 239 Tok.is(tok::utf8_char_constant) || // u8'x'. 240 Tok.is(tok::utf16_char_constant) || // u'x'. 241 Tok.is(tok::utf32_char_constant)) { // U'x'. 242 bool Invalid = false; 243 std::string TokStr = PP.getSpelling(Tok, &Invalid); 244 if (!Invalid) { 245 std::string Str = Lexer::Stringify(TokStr); 246 Result.append(Str.begin(), Str.end()); 247 } 248 } else if (Tok.is(tok::code_completion)) { 249 PP.CodeCompleteNaturalLanguage(); 250 } else { 251 // Otherwise, just append the token. Do some gymnastics to get the token 252 // in place and avoid copies where possible. 253 unsigned CurStrLen = Result.size(); 254 Result.resize(CurStrLen+Tok.getLength()); 255 const char *BufPtr = Result.data() + CurStrLen; 256 bool Invalid = false; 257 unsigned ActualTokLen = PP.getSpelling(Tok, BufPtr, &Invalid); 258 259 if (!Invalid) { 260 // If getSpelling returned a pointer to an already uniqued version of 261 // the string instead of filling in BufPtr, memcpy it onto our string. 262 if (ActualTokLen && BufPtr != &Result[CurStrLen]) 263 memcpy(&Result[CurStrLen], BufPtr, ActualTokLen); 264 265 // If the token was dirty, the spelling may be shorter than the token. 266 if (ActualTokLen != Tok.getLength()) 267 Result.resize(CurStrLen+ActualTokLen); 268 } 269 } 270 } 271 272 // If the last character of the string is a \, and if it isn't escaped, this 273 // is an invalid string literal, diagnose it as specified in C99. 274 if (Result.back() == '\\') { 275 // Count the number of consequtive \ characters. If even, then they are 276 // just escaped backslashes, otherwise it's an error. 277 unsigned FirstNonSlash = Result.size()-2; 278 // Guaranteed to find the starting " if nothing else. 279 while (Result[FirstNonSlash] == '\\') 280 --FirstNonSlash; 281 if ((Result.size()-1-FirstNonSlash) & 1) { 282 // Diagnose errors for things like: #define F(X) #X / F(\) 283 PP.Diag(ArgToks[-1], diag::pp_invalid_string_literal); 284 Result.pop_back(); // remove one of the \'s. 285 } 286 } 287 Result += '"'; 288 289 // If this is the charify operation and the result is not a legal character 290 // constant, diagnose it. 291 if (Charify) { 292 // First step, turn double quotes into single quotes: 293 Result[0] = '\''; 294 Result[Result.size()-1] = '\''; 295 296 // Check for bogus character. 297 bool isBad = false; 298 if (Result.size() == 3) 299 isBad = Result[1] == '\''; // ''' is not legal. '\' already fixed above. 300 else 301 isBad = (Result.size() != 4 || Result[1] != '\\'); // Not '\x' 302 303 if (isBad) { 304 PP.Diag(ArgTokStart[0], diag::err_invalid_character_to_charify); 305 Result = "' '"; // Use something arbitrary, but legal. 306 } 307 } 308 309 PP.CreateString(Result, Tok, 310 ExpansionLocStart, ExpansionLocEnd); 311 return Tok; 312} 313 314/// getStringifiedArgument - Compute, cache, and return the specified argument 315/// that has been 'stringified' as required by the # operator. 316const Token &MacroArgs::getStringifiedArgument(unsigned ArgNo, 317 Preprocessor &PP, 318 SourceLocation ExpansionLocStart, 319 SourceLocation ExpansionLocEnd) { 320 assert(ArgNo < getNumMacroArguments() && "Invalid argument number!"); 321 if (StringifiedArgs.empty()) 322 StringifiedArgs.resize(getNumMacroArguments(), {}); 323 324 if (StringifiedArgs[ArgNo].isNot(tok::string_literal)) 325 StringifiedArgs[ArgNo] = StringifyArgument(getUnexpArgument(ArgNo), PP, 326 /*Charify=*/false, 327 ExpansionLocStart, 328 ExpansionLocEnd); 329 return StringifiedArgs[ArgNo]; 330} 331