| //===--- TokenConcatenation.cpp - Token Concatenation Avoidance -----------===// |
| // |
| // The LLVM Compiler Infrastructure |
| // |
| // This file is distributed under the University of Illinois Open Source |
| // License. See LICENSE.TXT for details. |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| // This file implements the TokenConcatenation class. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #include "clang/Lex/TokenConcatenation.h" |
| #include "clang/Basic/CharInfo.h" |
| #include "clang/Lex/Preprocessor.h" |
| #include "llvm/Support/ErrorHandling.h" |
| using namespace clang; |
| |
| |
| /// IsStringPrefix - Return true if Str is a string prefix. |
| /// 'L', 'u', 'U', or 'u8'. Including raw versions. |
| static bool IsStringPrefix(StringRef Str, bool CPlusPlus11) { |
| |
| if (Str[0] == 'L' || |
| (CPlusPlus11 && (Str[0] == 'u' || Str[0] == 'U' || Str[0] == 'R'))) { |
| |
| if (Str.size() == 1) |
| return true; // "L", "u", "U", and "R" |
| |
| // Check for raw flavors. Need to make sure the first character wasn't |
| // already R. Need CPlusPlus11 check for "LR". |
| if (Str[1] == 'R' && Str[0] != 'R' && Str.size() == 2 && CPlusPlus11) |
| return true; // "LR", "uR", "UR" |
| |
| // Check for "u8" and "u8R" |
| if (Str[0] == 'u' && Str[1] == '8') { |
| if (Str.size() == 2) return true; // "u8" |
| if (Str.size() == 3 && Str[2] == 'R') return true; // "u8R" |
| } |
| } |
| |
| return false; |
| } |
| |
| /// IsIdentifierStringPrefix - Return true if the spelling of the token |
| /// is literally 'L', 'u', 'U', or 'u8'. Including raw versions. |
| bool TokenConcatenation::IsIdentifierStringPrefix(const Token &Tok) const { |
| const LangOptions &LangOpts = PP.getLangOpts(); |
| |
| if (!Tok.needsCleaning()) { |
| if (Tok.getLength() < 1 || Tok.getLength() > 3) |
| return false; |
| SourceManager &SM = PP.getSourceManager(); |
| const char *Ptr = SM.getCharacterData(SM.getSpellingLoc(Tok.getLocation())); |
| return IsStringPrefix(StringRef(Ptr, Tok.getLength()), |
| LangOpts.CPlusPlus11); |
| } |
| |
| if (Tok.getLength() < 256) { |
| char Buffer[256]; |
| const char *TokPtr = Buffer; |
| unsigned length = PP.getSpelling(Tok, TokPtr); |
| return IsStringPrefix(StringRef(TokPtr, length), LangOpts.CPlusPlus11); |
| } |
| |
| return IsStringPrefix(StringRef(PP.getSpelling(Tok)), LangOpts.CPlusPlus11); |
| } |
| |
| TokenConcatenation::TokenConcatenation(Preprocessor &pp) : PP(pp) { |
| memset(TokenInfo, 0, sizeof(TokenInfo)); |
| |
| // These tokens have custom code in AvoidConcat. |
| TokenInfo[tok::identifier ] |= aci_custom; |
| TokenInfo[tok::numeric_constant] |= aci_custom_firstchar; |
| TokenInfo[tok::period ] |= aci_custom_firstchar; |
| TokenInfo[tok::amp ] |= aci_custom_firstchar; |
| TokenInfo[tok::plus ] |= aci_custom_firstchar; |
| TokenInfo[tok::minus ] |= aci_custom_firstchar; |
| TokenInfo[tok::slash ] |= aci_custom_firstchar; |
| TokenInfo[tok::less ] |= aci_custom_firstchar; |
| TokenInfo[tok::greater ] |= aci_custom_firstchar; |
| TokenInfo[tok::pipe ] |= aci_custom_firstchar; |
| TokenInfo[tok::percent ] |= aci_custom_firstchar; |
| TokenInfo[tok::colon ] |= aci_custom_firstchar; |
| TokenInfo[tok::hash ] |= aci_custom_firstchar; |
| TokenInfo[tok::arrow ] |= aci_custom_firstchar; |
| |
| // These tokens have custom code in C++11 mode. |
| if (PP.getLangOpts().CPlusPlus11) { |
| TokenInfo[tok::string_literal ] |= aci_custom; |
| TokenInfo[tok::wide_string_literal ] |= aci_custom; |
| TokenInfo[tok::utf8_string_literal ] |= aci_custom; |
| TokenInfo[tok::utf16_string_literal] |= aci_custom; |
| TokenInfo[tok::utf32_string_literal] |= aci_custom; |
| TokenInfo[tok::char_constant ] |= aci_custom; |
| TokenInfo[tok::wide_char_constant ] |= aci_custom; |
| TokenInfo[tok::utf16_char_constant ] |= aci_custom; |
| TokenInfo[tok::utf32_char_constant ] |= aci_custom; |
| } |
| |
| // These tokens have custom code in C++17 mode. |
| if (PP.getLangOpts().CPlusPlus17) |
| TokenInfo[tok::utf8_char_constant] |= aci_custom; |
| |
| // These tokens have custom code in C++2a mode. |
| if (PP.getLangOpts().CPlusPlus2a) |
| TokenInfo[tok::lessequal ] |= aci_custom_firstchar; |
| |
| // These tokens change behavior if followed by an '='. |
| TokenInfo[tok::amp ] |= aci_avoid_equal; // &= |
| TokenInfo[tok::plus ] |= aci_avoid_equal; // += |
| TokenInfo[tok::minus ] |= aci_avoid_equal; // -= |
| TokenInfo[tok::slash ] |= aci_avoid_equal; // /= |
| TokenInfo[tok::less ] |= aci_avoid_equal; // <= |
| TokenInfo[tok::greater ] |= aci_avoid_equal; // >= |
| TokenInfo[tok::pipe ] |= aci_avoid_equal; // |= |
| TokenInfo[tok::percent ] |= aci_avoid_equal; // %= |
| TokenInfo[tok::star ] |= aci_avoid_equal; // *= |
| TokenInfo[tok::exclaim ] |= aci_avoid_equal; // != |
| TokenInfo[tok::lessless ] |= aci_avoid_equal; // <<= |
| TokenInfo[tok::greatergreater] |= aci_avoid_equal; // >>= |
| TokenInfo[tok::caret ] |= aci_avoid_equal; // ^= |
| TokenInfo[tok::equal ] |= aci_avoid_equal; // == |
| } |
| |
| /// GetFirstChar - Get the first character of the token \arg Tok, |
| /// avoiding calls to getSpelling where possible. |
| static char GetFirstChar(Preprocessor &PP, const Token &Tok) { |
| if (IdentifierInfo *II = Tok.getIdentifierInfo()) { |
| // Avoid spelling identifiers, the most common form of token. |
| return II->getNameStart()[0]; |
| } else if (!Tok.needsCleaning()) { |
| if (Tok.isLiteral() && Tok.getLiteralData()) { |
| return *Tok.getLiteralData(); |
| } else { |
| SourceManager &SM = PP.getSourceManager(); |
| return *SM.getCharacterData(SM.getSpellingLoc(Tok.getLocation())); |
| } |
| } else if (Tok.getLength() < 256) { |
| char Buffer[256]; |
| const char *TokPtr = Buffer; |
| PP.getSpelling(Tok, TokPtr); |
| return TokPtr[0]; |
| } else { |
| return PP.getSpelling(Tok)[0]; |
| } |
| } |
| |
| /// AvoidConcat - If printing PrevTok immediately followed by Tok would cause |
| /// the two individual tokens to be lexed as a single token, return true |
| /// (which causes a space to be printed between them). This allows the output |
| /// of -E mode to be lexed to the same token stream as lexing the input |
| /// directly would. |
| /// |
| /// This code must conservatively return true if it doesn't want to be 100% |
| /// accurate. This will cause the output to include extra space characters, |
| /// but the resulting output won't have incorrect concatenations going on. |
| /// Examples include "..", which we print with a space between, because we |
| /// don't want to track enough to tell "x.." from "...". |
| bool TokenConcatenation::AvoidConcat(const Token &PrevPrevTok, |
| const Token &PrevTok, |
| const Token &Tok) const { |
| // First, check to see if the tokens were directly adjacent in the original |
| // source. If they were, it must be okay to stick them together: if there |
| // were an issue, the tokens would have been lexed differently. |
| SourceManager &SM = PP.getSourceManager(); |
| SourceLocation PrevSpellLoc = SM.getSpellingLoc(PrevTok.getLocation()); |
| SourceLocation SpellLoc = SM.getSpellingLoc(Tok.getLocation()); |
| if (PrevSpellLoc.getLocWithOffset(PrevTok.getLength()) == SpellLoc) |
| return false; |
| |
| tok::TokenKind PrevKind = PrevTok.getKind(); |
| if (!PrevTok.isAnnotation() && PrevTok.getIdentifierInfo()) |
| PrevKind = tok::identifier; // Language keyword or named operator. |
| |
| // Look up information on when we should avoid concatenation with prevtok. |
| unsigned ConcatInfo = TokenInfo[PrevKind]; |
| |
| // If prevtok never causes a problem for anything after it, return quickly. |
| if (ConcatInfo == 0) return false; |
| |
| if (ConcatInfo & aci_avoid_equal) { |
| // If the next token is '=' or '==', avoid concatenation. |
| if (Tok.isOneOf(tok::equal, tok::equalequal)) |
| return true; |
| ConcatInfo &= ~aci_avoid_equal; |
| } |
| if (Tok.isAnnotation()) { |
| // Modules annotation can show up when generated automatically for includes. |
| assert(Tok.isOneOf(tok::annot_module_include, tok::annot_module_begin, |
| tok::annot_module_end) && |
| "unexpected annotation in AvoidConcat"); |
| ConcatInfo = 0; |
| } |
| |
| if (ConcatInfo == 0) |
| return false; |
| |
| // Basic algorithm: we look at the first character of the second token, and |
| // determine whether it, if appended to the first token, would form (or |
| // would contribute) to a larger token if concatenated. |
| char FirstChar = 0; |
| if (ConcatInfo & aci_custom) { |
| // If the token does not need to know the first character, don't get it. |
| } else { |
| FirstChar = GetFirstChar(PP, Tok); |
| } |
| |
| switch (PrevKind) { |
| default: |
| llvm_unreachable("InitAvoidConcatTokenInfo built wrong"); |
| |
| case tok::raw_identifier: |
| llvm_unreachable("tok::raw_identifier in non-raw lexing mode!"); |
| |
| case tok::string_literal: |
| case tok::wide_string_literal: |
| case tok::utf8_string_literal: |
| case tok::utf16_string_literal: |
| case tok::utf32_string_literal: |
| case tok::char_constant: |
| case tok::wide_char_constant: |
| case tok::utf8_char_constant: |
| case tok::utf16_char_constant: |
| case tok::utf32_char_constant: |
| if (!PP.getLangOpts().CPlusPlus11) |
| return false; |
| |
| // In C++11, a string or character literal followed by an identifier is a |
| // single token. |
| if (Tok.getIdentifierInfo()) |
| return true; |
| |
| // A ud-suffix is an identifier. If the previous token ends with one, treat |
| // it as an identifier. |
| if (!PrevTok.hasUDSuffix()) |
| return false; |
| LLVM_FALLTHROUGH; |
| case tok::identifier: // id+id or id+number or id+L"foo". |
| // id+'.'... will not append. |
| if (Tok.is(tok::numeric_constant)) |
| return GetFirstChar(PP, Tok) != '.'; |
| |
| if (Tok.getIdentifierInfo() || |
| Tok.isOneOf(tok::wide_string_literal, tok::utf8_string_literal, |
| tok::utf16_string_literal, tok::utf32_string_literal, |
| tok::wide_char_constant, tok::utf8_char_constant, |
| tok::utf16_char_constant, tok::utf32_char_constant)) |
| return true; |
| |
| // If this isn't identifier + string, we're done. |
| if (Tok.isNot(tok::char_constant) && Tok.isNot(tok::string_literal)) |
| return false; |
| |
| // Otherwise, this is a narrow character or string. If the *identifier* |
| // is a literal 'L', 'u8', 'u' or 'U', avoid pasting L "foo" -> L"foo". |
| return IsIdentifierStringPrefix(PrevTok); |
| |
| case tok::numeric_constant: |
| return isPreprocessingNumberBody(FirstChar) || |
| FirstChar == '+' || FirstChar == '-'; |
| case tok::period: // ..., .*, .1234 |
| return (FirstChar == '.' && PrevPrevTok.is(tok::period)) || |
| isDigit(FirstChar) || |
| (PP.getLangOpts().CPlusPlus && FirstChar == '*'); |
| case tok::amp: // && |
| return FirstChar == '&'; |
| case tok::plus: // ++ |
| return FirstChar == '+'; |
| case tok::minus: // --, ->, ->* |
| return FirstChar == '-' || FirstChar == '>'; |
| case tok::slash: //, /*, // |
| return FirstChar == '*' || FirstChar == '/'; |
| case tok::less: // <<, <<=, <:, <% |
| return FirstChar == '<' || FirstChar == ':' || FirstChar == '%'; |
| case tok::greater: // >>, >>= |
| return FirstChar == '>'; |
| case tok::pipe: // || |
| return FirstChar == '|'; |
| case tok::percent: // %>, %: |
| return FirstChar == '>' || FirstChar == ':'; |
| case tok::colon: // ::, :> |
| return FirstChar == '>' || |
| (PP.getLangOpts().CPlusPlus && FirstChar == ':'); |
| case tok::hash: // ##, #@, %:%: |
| return FirstChar == '#' || FirstChar == '@' || FirstChar == '%'; |
| case tok::arrow: // ->* |
| return PP.getLangOpts().CPlusPlus && FirstChar == '*'; |
| case tok::lessequal: // <=> (C++2a) |
| return PP.getLangOpts().CPlusPlus2a && FirstChar == '>'; |
| } |
| } |
