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//===--- NarrowingConversionsCheck.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 "NarrowingConversionsCheck.h"
#include "clang/AST/ASTContext.h"
#include "clang/ASTMatchers/ASTMatchFinder.h"
using namespace clang::ast_matchers;
namespace clang {
namespace tidy {
namespace cppcoreguidelines {
// FIXME: Check double -> float truncation. Pay attention to casts:
void NarrowingConversionsCheck::registerMatchers(MatchFinder *Finder) {
// ceil() and floor() are guaranteed to return integers, even though the type
// is not integral.
const auto IsCeilFloorCall = callExpr(callee(functionDecl(
hasAnyName("::ceil", "::std::ceil", "::floor", "::std::floor"))));
const auto IsFloatExpr =
expr(hasType(realFloatingPointType()), unless(IsCeilFloorCall));
// casts:
// i = 0.5;
// void f(int); f(0.5);
Finder->addMatcher(implicitCastExpr(hasImplicitDestinationType(isInteger()),
hasSourceExpression(IsFloatExpr),
unless(hasParent(castExpr())),
unless(isInTemplateInstantiation()))
.bind("cast"),
this);
// Binary operators:
// i += 0.5;
Finder->addMatcher(
binaryOperator(isAssignmentOperator(),
// The `=` case generates an implicit cast which is covered
// by the previous matcher.
unless(hasOperatorName("=")),
hasLHS(hasType(isInteger())), hasRHS(IsFloatExpr),
unless(isInTemplateInstantiation()))
.bind("op"),
this);
}
void NarrowingConversionsCheck::check(const MatchFinder::MatchResult &Result) {
if (const auto *Op = Result.Nodes.getNodeAs<BinaryOperator>("op")) {
if (Op->getLocStart().isMacroID())
return;
diag(Op->getOperatorLoc(), "narrowing conversion from %0 to %1")
<< Op->getRHS()->getType() << Op->getLHS()->getType();
return;
}
const auto *Cast = Result.Nodes.getNodeAs<ImplicitCastExpr>("cast");
if (Cast->getLocStart().isMacroID())
return;
diag(Cast->getExprLoc(), "narrowing conversion from %0 to %1")
<< Cast->getSubExpr()->getType() << Cast->getType();
}
} // namespace cppcoreguidelines
} // namespace tidy
} // namespace clang
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