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