forked from OSchip/llvm-project
73 lines
2.4 KiB
C++
73 lines
2.4 KiB
C++
//===--- IncorrectRoundings.cpp - clang-tidy ------------------------------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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#include "IncorrectRoundings.h"
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#include "clang/AST/DeclBase.h"
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#include "clang/AST/Type.h"
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#include "clang/ASTMatchers/ASTMatchFinder.h"
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#include "clang/ASTMatchers/ASTMatchers.h"
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#include "clang/Lex/Lexer.h"
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using namespace clang::ast_matchers;
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namespace clang {
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namespace tidy {
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namespace misc {
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namespace {
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AST_MATCHER(FloatingLiteral, floatHalf) {
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const auto &literal = Node.getValue();
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if ((&Node.getSemantics()) == &llvm::APFloat::IEEEsingle)
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return literal.convertToFloat() == 0.5f;
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if ((&Node.getSemantics()) == &llvm::APFloat::IEEEdouble)
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return literal.convertToDouble() == 0.5;
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return false;
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}
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} // namespace
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void IncorrectRoundings::registerMatchers(MatchFinder *MatchFinder) {
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// Match a floating literal with value 0.5.
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auto FloatHalf = floatLiteral(floatHalf());
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// Match a floating point expression.
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auto FloatType = expr(hasType(realFloatingPointType()));
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// Match a floating literal of 0.5 or a floating literal of 0.5 implicitly.
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// cast to floating type.
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auto FloatOrCastHalf =
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anyOf(FloatHalf,
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implicitCastExpr(FloatType, has(ignoringParenImpCasts(FloatHalf))));
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// Match if either the LHS or RHS is a floating literal of 0.5 or a floating
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// literal of 0.5 and the other is of type double or vice versa.
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auto OneSideHalf = anyOf(allOf(hasLHS(FloatOrCastHalf), hasRHS(FloatType)),
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allOf(hasRHS(FloatOrCastHalf), hasLHS(FloatType)));
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// Find expressions of cast to int of the sum of a floating point expression
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// and 0.5.
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MatchFinder->addMatcher(
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implicitCastExpr(
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hasImplicitDestinationType(isInteger()),
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ignoringParenCasts(binaryOperator(hasOperatorName("+"), OneSideHalf)))
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.bind("CastExpr"),
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this);
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}
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void IncorrectRoundings::check(const MatchFinder::MatchResult &Result) {
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const auto *CastExpr = Result.Nodes.getStmtAs<ImplicitCastExpr>("CastExpr");
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diag(CastExpr->getLocStart(),
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"casting (double + 0.5) to integer leads to incorrect rounding; "
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"consider using lround (#include <cmath>) instead");
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}
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} // namespace misc
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} // namespace tidy
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} // namespace clang
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