forked from OSchip/llvm-project
274 lines
9.0 KiB
C++
274 lines
9.0 KiB
C++
//===--- MacroParenthesesCheck.cpp - clang-tidy----------------------------===//
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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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#include "MacroParenthesesCheck.h"
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#include "clang/Frontend/CompilerInstance.h"
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#include "clang/Lex/PPCallbacks.h"
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#include "clang/Lex/Preprocessor.h"
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namespace clang {
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namespace tidy {
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namespace bugprone {
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namespace {
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class MacroParenthesesPPCallbacks : public PPCallbacks {
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public:
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MacroParenthesesPPCallbacks(Preprocessor *PP, MacroParenthesesCheck *Check)
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: PP(PP), Check(Check) {}
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void MacroDefined(const Token &MacroNameTok,
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const MacroDirective *MD) override {
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replacementList(MacroNameTok, MD->getMacroInfo());
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argument(MacroNameTok, MD->getMacroInfo());
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}
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private:
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/// Replacement list with calculations should be enclosed in parentheses.
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void replacementList(const Token &MacroNameTok, const MacroInfo *MI);
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/// Arguments should be enclosed in parentheses.
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void argument(const Token &MacroNameTok, const MacroInfo *MI);
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Preprocessor *PP;
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MacroParenthesesCheck *Check;
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};
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} // namespace
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/// Is argument surrounded properly with parentheses/braces/squares/commas?
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static bool isSurroundedLeft(const Token &T) {
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return T.isOneOf(tok::l_paren, tok::l_brace, tok::l_square, tok::comma,
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tok::semi);
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}
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/// Is argument surrounded properly with parentheses/braces/squares/commas?
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static bool isSurroundedRight(const Token &T) {
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return T.isOneOf(tok::r_paren, tok::r_brace, tok::r_square, tok::comma,
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tok::semi);
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}
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/// Is given TokenKind a keyword?
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static bool isKeyword(const Token &T) {
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// FIXME: better matching of keywords to avoid false positives.
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return T.isOneOf(tok::kw_if, tok::kw_case, tok::kw_const, tok::kw_struct);
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}
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/// Warning is written when one of these operators are not within parentheses.
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static bool isWarnOp(const Token &T) {
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// FIXME: This is an initial list of operators. It can be tweaked later to
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// get more positives or perhaps avoid some false positive.
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return T.isOneOf(tok::plus, tok::minus, tok::star, tok::slash, tok::percent,
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tok::amp, tok::pipe, tok::caret);
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}
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/// Is given Token a keyword that is used in variable declarations?
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static bool isVarDeclKeyword(const Token &T) {
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return T.isOneOf(tok::kw_bool, tok::kw_char, tok::kw_short, tok::kw_int,
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tok::kw_long, tok::kw_float, tok::kw_double, tok::kw_const,
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tok::kw_enum, tok::kw_inline, tok::kw_static, tok::kw_struct,
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tok::kw_signed, tok::kw_unsigned);
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}
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/// Is there a possible variable declaration at Tok?
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static bool possibleVarDecl(const MacroInfo *MI, const Token *Tok) {
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if (Tok == MI->tokens_end())
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return false;
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// If we see int/short/struct/etc., just assume this is a variable
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// declaration.
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if (isVarDeclKeyword(*Tok))
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return true;
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// Variable declarations start with identifier or coloncolon.
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if (!Tok->isOneOf(tok::identifier, tok::raw_identifier, tok::coloncolon))
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return false;
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// Skip possible types, etc
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while (Tok != MI->tokens_end() &&
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Tok->isOneOf(tok::identifier, tok::raw_identifier, tok::coloncolon,
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tok::star, tok::amp, tok::ampamp, tok::less,
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tok::greater))
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Tok++;
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// Return true for possible variable declarations.
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return Tok == MI->tokens_end() ||
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Tok->isOneOf(tok::equal, tok::semi, tok::l_square, tok::l_paren) ||
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isVarDeclKeyword(*Tok);
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}
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void MacroParenthesesPPCallbacks::replacementList(const Token &MacroNameTok,
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const MacroInfo *MI) {
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// Make sure macro replacement isn't a variable declaration.
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if (possibleVarDecl(MI, MI->tokens_begin()))
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return;
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// Count how deep we are in parentheses/braces/squares.
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int Count = 0;
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// SourceLocation for error
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SourceLocation Loc;
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for (auto TI = MI->tokens_begin(), TE = MI->tokens_end(); TI != TE; ++TI) {
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const Token &Tok = *TI;
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// Replacement list contains keywords, don't warn about it.
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if (isKeyword(Tok))
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return;
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// When replacement list contains comma/semi don't warn about it.
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if (Count == 0 && Tok.isOneOf(tok::comma, tok::semi))
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return;
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if (Tok.isOneOf(tok::l_paren, tok::l_brace, tok::l_square)) {
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++Count;
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} else if (Tok.isOneOf(tok::r_paren, tok::r_brace, tok::r_square)) {
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--Count;
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// If there are unbalanced parentheses don't write any warning
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if (Count < 0)
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return;
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} else if (Count == 0 && isWarnOp(Tok)) {
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// Heuristic for macros that are clearly not intended to be enclosed in
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// parentheses, macro starts with operator. For example:
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// #define X *10
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if (TI == MI->tokens_begin() && (TI + 1) != TE &&
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!Tok.isOneOf(tok::plus, tok::minus))
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return;
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// Don't warn about this macro if the last token is a star. For example:
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// #define X void *
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if ((TE - 1)->is(tok::star))
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return;
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Loc = Tok.getLocation();
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}
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}
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if (Loc.isValid()) {
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const Token &Last = *(MI->tokens_end() - 1);
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Check->diag(Loc, "macro replacement list should be enclosed in parentheses")
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<< FixItHint::CreateInsertion(MI->tokens_begin()->getLocation(), "(")
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<< FixItHint::CreateInsertion(Last.getLocation().getLocWithOffset(
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PP->getSpelling(Last).length()),
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")");
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}
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}
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void MacroParenthesesPPCallbacks::argument(const Token &MacroNameTok,
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const MacroInfo *MI) {
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// Skip variable declaration.
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bool VarDecl = possibleVarDecl(MI, MI->tokens_begin());
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// Skip the goto argument with an arbitrary number of subsequent stars.
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bool FoundGoto = false;
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for (auto TI = MI->tokens_begin(), TE = MI->tokens_end(); TI != TE; ++TI) {
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// First token.
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if (TI == MI->tokens_begin())
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continue;
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// Last token.
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if ((TI + 1) == MI->tokens_end())
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continue;
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const Token &Prev = *(TI - 1);
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const Token &Next = *(TI + 1);
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const Token &Tok = *TI;
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// There should not be extra parentheses in possible variable declaration.
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if (VarDecl) {
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if (Tok.isOneOf(tok::equal, tok::semi, tok::l_square, tok::l_paren))
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VarDecl = false;
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continue;
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}
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// There should not be extra parentheses for the goto argument.
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if (Tok.is(tok::kw_goto)) {
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FoundGoto = true;
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continue;
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}
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// Only interested in identifiers.
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if (!Tok.isOneOf(tok::identifier, tok::raw_identifier)) {
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FoundGoto = false;
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continue;
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}
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// Only interested in macro arguments.
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if (MI->getParameterNum(Tok.getIdentifierInfo()) < 0)
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continue;
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// Argument is surrounded with parentheses/squares/braces/commas.
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if (isSurroundedLeft(Prev) && isSurroundedRight(Next))
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continue;
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// Don't warn after hash/hashhash or before hashhash.
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if (Prev.isOneOf(tok::hash, tok::hashhash) || Next.is(tok::hashhash))
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continue;
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// Argument is a struct member.
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if (Prev.isOneOf(tok::period, tok::arrow, tok::coloncolon, tok::arrowstar,
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tok::periodstar))
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continue;
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// Argument is a namespace or class.
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if (Next.is(tok::coloncolon))
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continue;
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// String concatenation.
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if (isStringLiteral(Prev.getKind()) || isStringLiteral(Next.getKind()))
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continue;
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// Type/Var.
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if (isAnyIdentifier(Prev.getKind()) || isKeyword(Prev) ||
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isAnyIdentifier(Next.getKind()) || isKeyword(Next))
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continue;
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// Initialization.
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if (Next.is(tok::l_paren))
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continue;
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// Cast.
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if (Prev.is(tok::l_paren) && Next.is(tok::star) &&
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TI + 2 != MI->tokens_end() && (TI + 2)->is(tok::r_paren))
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continue;
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// Assignment/return, i.e. '=x;' or 'return x;'.
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if (Prev.isOneOf(tok::equal, tok::kw_return) && Next.is(tok::semi))
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continue;
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// C++ template parameters.
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if (PP->getLangOpts().CPlusPlus && Prev.isOneOf(tok::comma, tok::less) &&
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Next.isOneOf(tok::comma, tok::greater))
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continue;
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// Namespaces.
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if (Prev.is(tok::kw_namespace))
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continue;
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// Variadic templates
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if (MI->isVariadic())
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continue;
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if (!FoundGoto) {
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Check->diag(Tok.getLocation(), "macro argument should be enclosed in "
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"parentheses")
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<< FixItHint::CreateInsertion(Tok.getLocation(), "(")
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<< FixItHint::CreateInsertion(Tok.getLocation().getLocWithOffset(
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PP->getSpelling(Tok).length()),
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")");
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}
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FoundGoto = false;
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}
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}
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void MacroParenthesesCheck::registerPPCallbacks(
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const SourceManager &SM, Preprocessor *PP, Preprocessor *ModuleExpanderPP) {
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PP->addPPCallbacks(std::make_unique<MacroParenthesesPPCallbacks>(PP, this));
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}
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} // namespace bugprone
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} // namespace tidy
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} // namespace clang
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