298 lines
12 KiB
C++
298 lines
12 KiB
C++
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//===--- TokenConcatenation.cpp - Token Concatenation Avoidance -----------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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//
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// This file implements the TokenConcatenation class.
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//
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//===----------------------------------------------------------------------===//
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#include "clang/Lex/TokenConcatenation.h"
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#include "clang/Basic/CharInfo.h"
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#include "clang/Lex/Preprocessor.h"
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#include "llvm/Support/ErrorHandling.h"
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using namespace clang;
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/// IsStringPrefix - Return true if Str is a string prefix.
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/// 'L', 'u', 'U', or 'u8'. Including raw versions.
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static bool IsStringPrefix(StringRef Str, bool CPlusPlus11) {
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if (Str[0] == 'L' ||
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(CPlusPlus11 && (Str[0] == 'u' || Str[0] == 'U' || Str[0] == 'R'))) {
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if (Str.size() == 1)
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return true; // "L", "u", "U", and "R"
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// Check for raw flavors. Need to make sure the first character wasn't
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// already R. Need CPlusPlus11 check for "LR".
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if (Str[1] == 'R' && Str[0] != 'R' && Str.size() == 2 && CPlusPlus11)
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return true; // "LR", "uR", "UR"
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// Check for "u8" and "u8R"
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if (Str[0] == 'u' && Str[1] == '8') {
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if (Str.size() == 2) return true; // "u8"
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if (Str.size() == 3 && Str[2] == 'R') return true; // "u8R"
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}
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}
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return false;
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}
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/// IsIdentifierStringPrefix - Return true if the spelling of the token
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/// is literally 'L', 'u', 'U', or 'u8'. Including raw versions.
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bool TokenConcatenation::IsIdentifierStringPrefix(const Token &Tok) const {
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const LangOptions &LangOpts = PP.getLangOpts();
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if (!Tok.needsCleaning()) {
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if (Tok.getLength() < 1 || Tok.getLength() > 3)
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return false;
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SourceManager &SM = PP.getSourceManager();
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const char *Ptr = SM.getCharacterData(SM.getSpellingLoc(Tok.getLocation()));
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return IsStringPrefix(StringRef(Ptr, Tok.getLength()),
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LangOpts.CPlusPlus11);
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}
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if (Tok.getLength() < 256) {
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char Buffer[256];
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const char *TokPtr = Buffer;
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unsigned length = PP.getSpelling(Tok, TokPtr);
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return IsStringPrefix(StringRef(TokPtr, length), LangOpts.CPlusPlus11);
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}
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return IsStringPrefix(StringRef(PP.getSpelling(Tok)), LangOpts.CPlusPlus11);
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}
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TokenConcatenation::TokenConcatenation(const Preprocessor &pp) : PP(pp) {
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memset(TokenInfo, 0, sizeof(TokenInfo));
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// These tokens have custom code in AvoidConcat.
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TokenInfo[tok::identifier ] |= aci_custom;
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TokenInfo[tok::numeric_constant] |= aci_custom_firstchar;
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TokenInfo[tok::period ] |= aci_custom_firstchar;
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TokenInfo[tok::amp ] |= aci_custom_firstchar;
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TokenInfo[tok::plus ] |= aci_custom_firstchar;
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TokenInfo[tok::minus ] |= aci_custom_firstchar;
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TokenInfo[tok::slash ] |= aci_custom_firstchar;
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TokenInfo[tok::less ] |= aci_custom_firstchar;
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TokenInfo[tok::greater ] |= aci_custom_firstchar;
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TokenInfo[tok::pipe ] |= aci_custom_firstchar;
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TokenInfo[tok::percent ] |= aci_custom_firstchar;
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TokenInfo[tok::colon ] |= aci_custom_firstchar;
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TokenInfo[tok::hash ] |= aci_custom_firstchar;
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TokenInfo[tok::arrow ] |= aci_custom_firstchar;
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// These tokens have custom code in C++11 mode.
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if (PP.getLangOpts().CPlusPlus11) {
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TokenInfo[tok::string_literal ] |= aci_custom;
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TokenInfo[tok::wide_string_literal ] |= aci_custom;
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TokenInfo[tok::utf8_string_literal ] |= aci_custom;
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TokenInfo[tok::utf16_string_literal] |= aci_custom;
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TokenInfo[tok::utf32_string_literal] |= aci_custom;
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TokenInfo[tok::char_constant ] |= aci_custom;
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TokenInfo[tok::wide_char_constant ] |= aci_custom;
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TokenInfo[tok::utf16_char_constant ] |= aci_custom;
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TokenInfo[tok::utf32_char_constant ] |= aci_custom;
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}
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// These tokens have custom code in C++17 mode.
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if (PP.getLangOpts().CPlusPlus17)
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TokenInfo[tok::utf8_char_constant] |= aci_custom;
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// These tokens have custom code in C++2a mode.
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if (PP.getLangOpts().CPlusPlus20)
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TokenInfo[tok::lessequal ] |= aci_custom_firstchar;
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// These tokens change behavior if followed by an '='.
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TokenInfo[tok::amp ] |= aci_avoid_equal; // &=
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TokenInfo[tok::plus ] |= aci_avoid_equal; // +=
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TokenInfo[tok::minus ] |= aci_avoid_equal; // -=
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TokenInfo[tok::slash ] |= aci_avoid_equal; // /=
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TokenInfo[tok::less ] |= aci_avoid_equal; // <=
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TokenInfo[tok::greater ] |= aci_avoid_equal; // >=
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TokenInfo[tok::pipe ] |= aci_avoid_equal; // |=
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TokenInfo[tok::percent ] |= aci_avoid_equal; // %=
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TokenInfo[tok::star ] |= aci_avoid_equal; // *=
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TokenInfo[tok::exclaim ] |= aci_avoid_equal; // !=
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TokenInfo[tok::lessless ] |= aci_avoid_equal; // <<=
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TokenInfo[tok::greatergreater] |= aci_avoid_equal; // >>=
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TokenInfo[tok::caret ] |= aci_avoid_equal; // ^=
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TokenInfo[tok::equal ] |= aci_avoid_equal; // ==
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}
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/// GetFirstChar - Get the first character of the token \arg Tok,
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/// avoiding calls to getSpelling where possible.
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static char GetFirstChar(const Preprocessor &PP, const Token &Tok) {
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if (IdentifierInfo *II = Tok.getIdentifierInfo()) {
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// Avoid spelling identifiers, the most common form of token.
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return II->getNameStart()[0];
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} else if (!Tok.needsCleaning()) {
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if (Tok.isLiteral() && Tok.getLiteralData()) {
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return *Tok.getLiteralData();
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} else {
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SourceManager &SM = PP.getSourceManager();
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return *SM.getCharacterData(SM.getSpellingLoc(Tok.getLocation()));
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}
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} else if (Tok.getLength() < 256) {
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char Buffer[256];
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const char *TokPtr = Buffer;
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PP.getSpelling(Tok, TokPtr);
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return TokPtr[0];
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} else {
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return PP.getSpelling(Tok)[0];
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}
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}
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/// AvoidConcat - If printing PrevTok immediately followed by Tok would cause
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/// the two individual tokens to be lexed as a single token, return true
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/// (which causes a space to be printed between them). This allows the output
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/// of -E mode to be lexed to the same token stream as lexing the input
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/// directly would.
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///
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/// This code must conservatively return true if it doesn't want to be 100%
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/// accurate. This will cause the output to include extra space characters,
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/// but the resulting output won't have incorrect concatenations going on.
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/// Examples include "..", which we print with a space between, because we
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/// don't want to track enough to tell "x.." from "...".
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bool TokenConcatenation::AvoidConcat(const Token &PrevPrevTok,
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const Token &PrevTok,
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const Token &Tok) const {
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// Conservatively assume that every annotation token that has a printable
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// form requires whitespace.
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if (PrevTok.isAnnotation())
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return true;
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// First, check to see if the tokens were directly adjacent in the original
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// source. If they were, it must be okay to stick them together: if there
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// were an issue, the tokens would have been lexed differently.
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SourceManager &SM = PP.getSourceManager();
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SourceLocation PrevSpellLoc = SM.getSpellingLoc(PrevTok.getLocation());
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SourceLocation SpellLoc = SM.getSpellingLoc(Tok.getLocation());
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if (PrevSpellLoc.getLocWithOffset(PrevTok.getLength()) == SpellLoc)
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return false;
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tok::TokenKind PrevKind = PrevTok.getKind();
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if (!PrevTok.isAnnotation() && PrevTok.getIdentifierInfo())
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PrevKind = tok::identifier; // Language keyword or named operator.
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// Look up information on when we should avoid concatenation with prevtok.
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unsigned ConcatInfo = TokenInfo[PrevKind];
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// If prevtok never causes a problem for anything after it, return quickly.
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if (ConcatInfo == 0) return false;
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if (ConcatInfo & aci_avoid_equal) {
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// If the next token is '=' or '==', avoid concatenation.
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if (Tok.isOneOf(tok::equal, tok::equalequal))
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return true;
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ConcatInfo &= ~aci_avoid_equal;
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}
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if (Tok.isAnnotation()) {
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// Modules annotation can show up when generated automatically for includes.
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assert(Tok.isOneOf(tok::annot_module_include, tok::annot_module_begin,
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tok::annot_module_end) &&
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"unexpected annotation in AvoidConcat");
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ConcatInfo = 0;
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}
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if (ConcatInfo == 0)
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return false;
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// Basic algorithm: we look at the first character of the second token, and
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// determine whether it, if appended to the first token, would form (or
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// would contribute) to a larger token if concatenated.
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char FirstChar = 0;
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if (ConcatInfo & aci_custom) {
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// If the token does not need to know the first character, don't get it.
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} else {
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FirstChar = GetFirstChar(PP, Tok);
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}
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switch (PrevKind) {
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default:
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llvm_unreachable("InitAvoidConcatTokenInfo built wrong");
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case tok::raw_identifier:
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llvm_unreachable("tok::raw_identifier in non-raw lexing mode!");
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case tok::string_literal:
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case tok::wide_string_literal:
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case tok::utf8_string_literal:
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case tok::utf16_string_literal:
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case tok::utf32_string_literal:
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case tok::char_constant:
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case tok::wide_char_constant:
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case tok::utf8_char_constant:
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case tok::utf16_char_constant:
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case tok::utf32_char_constant:
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if (!PP.getLangOpts().CPlusPlus11)
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return false;
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// In C++11, a string or character literal followed by an identifier is a
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// single token.
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if (Tok.getIdentifierInfo())
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return true;
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// A ud-suffix is an identifier. If the previous token ends with one, treat
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// it as an identifier.
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if (!PrevTok.hasUDSuffix())
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return false;
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LLVM_FALLTHROUGH;
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case tok::identifier: // id+id or id+number or id+L"foo".
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// id+'.'... will not append.
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if (Tok.is(tok::numeric_constant))
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return GetFirstChar(PP, Tok) != '.';
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if (Tok.getIdentifierInfo() ||
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Tok.isOneOf(tok::wide_string_literal, tok::utf8_string_literal,
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tok::utf16_string_literal, tok::utf32_string_literal,
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tok::wide_char_constant, tok::utf8_char_constant,
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tok::utf16_char_constant, tok::utf32_char_constant))
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return true;
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// If this isn't identifier + string, we're done.
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if (Tok.isNot(tok::char_constant) && Tok.isNot(tok::string_literal))
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return false;
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// Otherwise, this is a narrow character or string. If the *identifier*
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// is a literal 'L', 'u8', 'u' or 'U', avoid pasting L "foo" -> L"foo".
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return IsIdentifierStringPrefix(PrevTok);
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case tok::numeric_constant:
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return isPreprocessingNumberBody(FirstChar) ||
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FirstChar == '+' || FirstChar == '-';
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case tok::period: // ..., .*, .1234
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return (FirstChar == '.' && PrevPrevTok.is(tok::period)) ||
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isDigit(FirstChar) ||
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(PP.getLangOpts().CPlusPlus && FirstChar == '*');
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case tok::amp: // &&
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return FirstChar == '&';
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case tok::plus: // ++
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return FirstChar == '+';
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case tok::minus: // --, ->, ->*
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return FirstChar == '-' || FirstChar == '>';
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case tok::slash: //, /*, //
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return FirstChar == '*' || FirstChar == '/';
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case tok::less: // <<, <<=, <:, <%
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return FirstChar == '<' || FirstChar == ':' || FirstChar == '%';
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case tok::greater: // >>, >>=
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return FirstChar == '>';
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case tok::pipe: // ||
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return FirstChar == '|';
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case tok::percent: // %>, %:
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return FirstChar == '>' || FirstChar == ':';
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case tok::colon: // ::, :>
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return FirstChar == '>' ||
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(PP.getLangOpts().CPlusPlus && FirstChar == ':');
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case tok::hash: // ##, #@, %:%:
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return FirstChar == '#' || FirstChar == '@' || FirstChar == '%';
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case tok::arrow: // ->*
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return PP.getLangOpts().CPlusPlus && FirstChar == '*';
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case tok::lessequal: // <=> (C++2a)
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return PP.getLangOpts().CPlusPlus20 && FirstChar == '>';
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}
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}
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