forked from OSchip/llvm-project
103 lines
4.0 KiB
C++
103 lines
4.0 KiB
C++
//===--- SwappedArgumentsCheck.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 "SwappedArgumentsCheck.h"
|
|
#include "clang/AST/ASTContext.h"
|
|
#include "clang/Lex/Lexer.h"
|
|
#include "clang/Tooling/FixIt.h"
|
|
#include "llvm/ADT/SmallPtrSet.h"
|
|
|
|
using namespace clang::ast_matchers;
|
|
|
|
namespace clang {
|
|
namespace tidy {
|
|
namespace misc {
|
|
|
|
void SwappedArgumentsCheck::registerMatchers(MatchFinder *Finder) {
|
|
Finder->addMatcher(callExpr().bind("call"), this);
|
|
}
|
|
|
|
/// \brief Look through lvalue to rvalue and nop casts. This filters out
|
|
/// implicit conversions that have no effect on the input but block our view for
|
|
/// other implicit casts.
|
|
static const Expr *ignoreNoOpCasts(const Expr *E) {
|
|
if (auto *Cast = dyn_cast<CastExpr>(E))
|
|
if (Cast->getCastKind() == CK_LValueToRValue ||
|
|
Cast->getCastKind() == CK_NoOp)
|
|
return ignoreNoOpCasts(Cast->getSubExpr());
|
|
return E;
|
|
}
|
|
|
|
/// \brief Restrict the warning to implicit casts that are most likely
|
|
/// accidental. User defined or integral conversions fit in this category,
|
|
/// lvalue to rvalue or derived to base does not.
|
|
static bool isImplicitCastCandidate(const CastExpr *Cast) {
|
|
return Cast->getCastKind() == CK_UserDefinedConversion ||
|
|
Cast->getCastKind() == CK_FloatingToBoolean ||
|
|
Cast->getCastKind() == CK_FloatingToIntegral ||
|
|
Cast->getCastKind() == CK_IntegralToBoolean ||
|
|
Cast->getCastKind() == CK_IntegralToFloating ||
|
|
Cast->getCastKind() == CK_MemberPointerToBoolean ||
|
|
Cast->getCastKind() == CK_PointerToBoolean;
|
|
}
|
|
|
|
void SwappedArgumentsCheck::check(const MatchFinder::MatchResult &Result) {
|
|
const ASTContext &Ctx = *Result.Context;
|
|
const auto *Call = Result.Nodes.getStmtAs<CallExpr>("call");
|
|
|
|
llvm::SmallPtrSet<const Expr *, 4> UsedArgs;
|
|
for (unsigned I = 1, E = Call->getNumArgs(); I < E; ++I) {
|
|
const Expr *LHS = Call->getArg(I - 1);
|
|
const Expr *RHS = Call->getArg(I);
|
|
|
|
// Only need to check RHS, as LHS has already been covered. We don't want to
|
|
// emit two warnings for a single argument.
|
|
if (UsedArgs.count(RHS))
|
|
continue;
|
|
|
|
const auto *LHSCast = dyn_cast<ImplicitCastExpr>(ignoreNoOpCasts(LHS));
|
|
const auto *RHSCast = dyn_cast<ImplicitCastExpr>(ignoreNoOpCasts(RHS));
|
|
|
|
// Look if this is a potentially swapped argument pair. First look for
|
|
// implicit casts.
|
|
if (!LHSCast || !RHSCast || !isImplicitCastCandidate(LHSCast) ||
|
|
!isImplicitCastCandidate(RHSCast))
|
|
continue;
|
|
|
|
// If the types that go into the implicit casts match the types of the other
|
|
// argument in the declaration there is a high probability that the
|
|
// arguments were swapped.
|
|
// TODO: We could make use of the edit distance between the argument name
|
|
// and the name of the passed variable in addition to this type based
|
|
// heuristic.
|
|
const Expr *LHSFrom = ignoreNoOpCasts(LHSCast->getSubExpr());
|
|
const Expr *RHSFrom = ignoreNoOpCasts(RHSCast->getSubExpr());
|
|
if (LHS->getType() == RHS->getType() ||
|
|
LHS->getType() != RHSFrom->getType() ||
|
|
RHS->getType() != LHSFrom->getType())
|
|
continue;
|
|
|
|
// Emit a warning and fix-its that swap the arguments.
|
|
diag(Call->getLocStart(), "argument with implicit conversion from %0 "
|
|
"to %1 followed by argument converted from "
|
|
"%2 to %3, potentially swapped arguments.")
|
|
<< LHS->getType() << LHSFrom->getType() << RHS->getType()
|
|
<< RHSFrom->getType()
|
|
<< tooling::fixit::createReplacement(*LHS, *RHS, Ctx)
|
|
<< tooling::fixit::createReplacement(*RHS, *LHS, Ctx);
|
|
|
|
// Remember that we emitted a warning for this argument.
|
|
UsedArgs.insert(RHSCast);
|
|
}
|
|
}
|
|
|
|
} // namespace misc
|
|
} // namespace tidy
|
|
} // namespace clang
|