1 //===--- MacroArgs.cpp - Formal argument info for Macros ------------------===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 // 9 // This file implements the MacroArgs interface. 10 // 11 //===----------------------------------------------------------------------===// 12 13 #include "clang/Lex/MacroArgs.h" 14 #include "clang/Lex/LexDiagnostic.h" 15 #include "clang/Lex/MacroInfo.h" 16 #include "clang/Lex/Preprocessor.h" 17 #include "llvm/Support/SaveAndRestore.h" 18 #include <algorithm> 19 20 using namespace clang; 21 22 /// MacroArgs ctor function - This destroys the vector passed in. 23 MacroArgs *MacroArgs::create(const MacroInfo *MI, 24 ArrayRef<Token> UnexpArgTokens, 25 bool VarargsElided, Preprocessor &PP) { 26 assert(MI->isFunctionLike() && 27 "Can't have args for an object-like macro!"); 28 MacroArgs **ResultEnt = nullptr; 29 unsigned ClosestMatch = ~0U; 30 31 // See if we have an entry with a big enough argument list to reuse on the 32 // free list. If so, reuse it. 33 for (MacroArgs **Entry = &PP.MacroArgCache; *Entry; 34 Entry = &(*Entry)->ArgCache) { 35 if ((*Entry)->NumUnexpArgTokens >= UnexpArgTokens.size() && 36 (*Entry)->NumUnexpArgTokens < ClosestMatch) { 37 ResultEnt = Entry; 38 39 // If we have an exact match, use it. 40 if ((*Entry)->NumUnexpArgTokens == UnexpArgTokens.size()) 41 break; 42 // Otherwise, use the best fit. 43 ClosestMatch = (*Entry)->NumUnexpArgTokens; 44 } 45 } 46 MacroArgs *Result; 47 if (!ResultEnt) { 48 // Allocate memory for a MacroArgs object with the lexer tokens at the end, 49 // and construct the MacroArgs object. 50 Result = new ( 51 llvm::safe_malloc(totalSizeToAlloc<Token>(UnexpArgTokens.size()))) 52 MacroArgs(UnexpArgTokens.size(), VarargsElided, MI->getNumParams()); 53 } else { 54 Result = *ResultEnt; 55 // Unlink this node from the preprocessors singly linked list. 56 *ResultEnt = Result->ArgCache; 57 Result->NumUnexpArgTokens = UnexpArgTokens.size(); 58 Result->VarargsElided = VarargsElided; 59 Result->NumMacroArgs = MI->getNumParams(); 60 } 61 62 // Copy the actual unexpanded tokens to immediately after the result ptr. 63 if (!UnexpArgTokens.empty()) { 64 static_assert(std::is_trivial_v<Token>, 65 "assume trivial copyability if copying into the " 66 "uninitialized array (as opposed to reusing a cached " 67 "MacroArgs)"); 68 std::copy(UnexpArgTokens.begin(), UnexpArgTokens.end(), 69 Result->getTrailingObjects<Token>()); 70 } 71 72 return Result; 73 } 74 75 /// destroy - Destroy and deallocate the memory for this object. 76 /// 77 void MacroArgs::destroy(Preprocessor &PP) { 78 // Don't clear PreExpArgTokens, just clear the entries. Clearing the entries 79 // would deallocate the element vectors. 80 for (unsigned i = 0, e = PreExpArgTokens.size(); i != e; ++i) 81 PreExpArgTokens[i].clear(); 82 83 // Add this to the preprocessor's free list. 84 ArgCache = PP.MacroArgCache; 85 PP.MacroArgCache = this; 86 } 87 88 /// deallocate - This should only be called by the Preprocessor when managing 89 /// its freelist. 90 MacroArgs *MacroArgs::deallocate() { 91 MacroArgs *Next = ArgCache; 92 93 // Run the dtor to deallocate the vectors. 94 this->~MacroArgs(); 95 // Release the memory for the object. 96 static_assert(std::is_trivially_destructible_v<Token>, 97 "assume trivially destructible and forego destructors"); 98 free(this); 99 100 return Next; 101 } 102 103 104 /// getArgLength - Given a pointer to an expanded or unexpanded argument, 105 /// return the number of tokens, not counting the EOF, that make up the 106 /// argument. 107 unsigned MacroArgs::getArgLength(const Token *ArgPtr) { 108 unsigned NumArgTokens = 0; 109 for (; ArgPtr->isNot(tok::eof); ++ArgPtr) 110 ++NumArgTokens; 111 return NumArgTokens; 112 } 113 114 115 /// getUnexpArgument - Return the unexpanded tokens for the specified formal. 116 /// 117 const Token *MacroArgs::getUnexpArgument(unsigned Arg) const { 118 119 assert(Arg < getNumMacroArguments() && "Invalid arg #"); 120 // The unexpanded argument tokens start immediately after the MacroArgs object 121 // in memory. 122 const Token *Start = getTrailingObjects<Token>(); 123 const Token *Result = Start; 124 125 // Scan to find Arg. 126 for (; Arg; ++Result) { 127 assert(Result < Start+NumUnexpArgTokens && "Invalid arg #"); 128 if (Result->is(tok::eof)) 129 --Arg; 130 } 131 assert(Result < Start+NumUnexpArgTokens && "Invalid arg #"); 132 return Result; 133 } 134 135 bool MacroArgs::invokedWithVariadicArgument(const MacroInfo *const MI, 136 Preprocessor &PP) { 137 if (!MI->isVariadic()) 138 return false; 139 const int VariadicArgIndex = getNumMacroArguments() - 1; 140 return getPreExpArgument(VariadicArgIndex, PP).front().isNot(tok::eof); 141 } 142 143 /// ArgNeedsPreexpansion - If we can prove that the argument won't be affected 144 /// by pre-expansion, return false. Otherwise, conservatively return true. 145 bool MacroArgs::ArgNeedsPreexpansion(const Token *ArgTok, 146 Preprocessor &PP) const { 147 // If there are no identifiers in the argument list, or if the identifiers are 148 // known to not be macros, pre-expansion won't modify it. 149 for (; ArgTok->isNot(tok::eof); ++ArgTok) 150 if (IdentifierInfo *II = ArgTok->getIdentifierInfo()) 151 if (II->hasMacroDefinition()) 152 // Return true even though the macro could be a function-like macro 153 // without a following '(' token, or could be disabled, or not visible. 154 return true; 155 return false; 156 } 157 158 /// getPreExpArgument - Return the pre-expanded form of the specified 159 /// argument. 160 const std::vector<Token> &MacroArgs::getPreExpArgument(unsigned Arg, 161 Preprocessor &PP) { 162 assert(Arg < getNumMacroArguments() && "Invalid argument number!"); 163 164 // If we have already computed this, return it. 165 if (PreExpArgTokens.size() < getNumMacroArguments()) 166 PreExpArgTokens.resize(getNumMacroArguments()); 167 168 std::vector<Token> &Result = PreExpArgTokens[Arg]; 169 if (!Result.empty()) return Result; 170 171 SaveAndRestore PreExpandingMacroArgs(PP.InMacroArgPreExpansion, true); 172 173 const Token *AT = getUnexpArgument(Arg); 174 unsigned NumToks = getArgLength(AT)+1; // Include the EOF. 175 176 // Otherwise, we have to pre-expand this argument, populating Result. To do 177 // this, we set up a fake TokenLexer to lex from the unexpanded argument 178 // list. With this installed, we lex expanded tokens until we hit the EOF 179 // token at the end of the unexp list. 180 PP.EnterTokenStream(AT, NumToks, false /*disable expand*/, 181 false /*owns tokens*/, false /*is reinject*/); 182 183 // Lex all of the macro-expanded tokens into Result. 184 do { 185 Result.push_back(Token()); 186 Token &Tok = Result.back(); 187 PP.Lex(Tok); 188 } while (Result.back().isNot(tok::eof)); 189 190 // Pop the token stream off the top of the stack. We know that the internal 191 // pointer inside of it is to the "end" of the token stream, but the stack 192 // will not otherwise be popped until the next token is lexed. The problem is 193 // that the token may be lexed sometime after the vector of tokens itself is 194 // destroyed, which would be badness. 195 if (PP.InCachingLexMode()) 196 PP.ExitCachingLexMode(); 197 PP.RemoveTopOfLexerStack(); 198 return Result; 199 } 200 201 202 /// StringifyArgument - Implement C99 6.10.3.2p2, converting a sequence of 203 /// tokens into the literal string token that should be produced by the C # 204 /// preprocessor operator. If Charify is true, then it should be turned into 205 /// a character literal for the Microsoft charize (#@) extension. 206 /// 207 Token MacroArgs::StringifyArgument(const Token *ArgToks, 208 Preprocessor &PP, bool Charify, 209 SourceLocation ExpansionLocStart, 210 SourceLocation ExpansionLocEnd) { 211 Token Tok; 212 Tok.startToken(); 213 Tok.setKind(Charify ? tok::char_constant : tok::string_literal); 214 215 const Token *ArgTokStart = ArgToks; 216 217 // Stringify all the tokens. 218 SmallString<128> Result; 219 Result += "\""; 220 221 bool isFirst = true; 222 for (; ArgToks->isNot(tok::eof); ++ArgToks) { 223 const Token &Tok = *ArgToks; 224 if (!isFirst && (Tok.hasLeadingSpace() || Tok.isAtStartOfLine())) 225 Result += ' '; 226 isFirst = false; 227 228 // If this is a string or character constant, escape the token as specified 229 // by 6.10.3.2p2. 230 if (tok::isStringLiteral(Tok.getKind()) || // "foo", u8R"x(foo)x"_bar, etc. 231 Tok.is(tok::char_constant) || // 'x' 232 Tok.is(tok::wide_char_constant) || // L'x'. 233 Tok.is(tok::utf8_char_constant) || // u8'x'. 234 Tok.is(tok::utf16_char_constant) || // u'x'. 235 Tok.is(tok::utf32_char_constant)) { // U'x'. 236 bool Invalid = false; 237 std::string TokStr = PP.getSpelling(Tok, &Invalid); 238 if (!Invalid) { 239 std::string Str = Lexer::Stringify(TokStr); 240 Result.append(Str.begin(), Str.end()); 241 } 242 } else if (Tok.is(tok::code_completion)) { 243 PP.CodeCompleteNaturalLanguage(); 244 } else { 245 // Otherwise, just append the token. Do some gymnastics to get the token 246 // in place and avoid copies where possible. 247 unsigned CurStrLen = Result.size(); 248 Result.resize(CurStrLen+Tok.getLength()); 249 const char *BufPtr = Result.data() + CurStrLen; 250 bool Invalid = false; 251 unsigned ActualTokLen = PP.getSpelling(Tok, BufPtr, &Invalid); 252 253 if (!Invalid) { 254 // If getSpelling returned a pointer to an already uniqued version of 255 // the string instead of filling in BufPtr, memcpy it onto our string. 256 if (ActualTokLen && BufPtr != &Result[CurStrLen]) 257 memcpy(&Result[CurStrLen], BufPtr, ActualTokLen); 258 259 // If the token was dirty, the spelling may be shorter than the token. 260 if (ActualTokLen != Tok.getLength()) 261 Result.resize(CurStrLen+ActualTokLen); 262 } 263 } 264 } 265 266 // If the last character of the string is a \, and if it isn't escaped, this 267 // is an invalid string literal, diagnose it as specified in C99. 268 if (Result.back() == '\\') { 269 // Count the number of consecutive \ characters. If even, then they are 270 // just escaped backslashes, otherwise it's an error. 271 unsigned FirstNonSlash = Result.size()-2; 272 // Guaranteed to find the starting " if nothing else. 273 while (Result[FirstNonSlash] == '\\') 274 --FirstNonSlash; 275 if ((Result.size()-1-FirstNonSlash) & 1) { 276 // Diagnose errors for things like: #define F(X) #X / F(\) 277 PP.Diag(ArgToks[-1], diag::pp_invalid_string_literal); 278 Result.pop_back(); // remove one of the \'s. 279 } 280 } 281 Result += '"'; 282 283 // If this is the charify operation and the result is not a legal character 284 // constant, diagnose it. 285 if (Charify) { 286 // First step, turn double quotes into single quotes: 287 Result[0] = '\''; 288 Result[Result.size()-1] = '\''; 289 290 // Check for bogus character. 291 bool isBad = false; 292 if (Result.size() == 3) 293 isBad = Result[1] == '\''; // ''' is not legal. '\' already fixed above. 294 else 295 isBad = (Result.size() != 4 || Result[1] != '\\'); // Not '\x' 296 297 if (isBad) { 298 PP.Diag(ArgTokStart[0], diag::err_invalid_character_to_charify); 299 Result = "' '"; // Use something arbitrary, but legal. 300 } 301 } 302 303 PP.CreateString(Result, Tok, 304 ExpansionLocStart, ExpansionLocEnd); 305 return Tok; 306 } 307