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//===--- UseStdMinMaxCheck.cpp - clang-tidy -------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#include "UseStdMinMaxCheck.h"
#include "../utils/ASTUtils.h"
#include "clang/AST/ASTContext.h"
#include "clang/ASTMatchers/ASTMatchFinder.h"
#include "clang/Lex/Preprocessor.h"
using namespace clang::ast_matchers;
namespace clang::tidy::readability {
namespace {
// Ignore if statements that are inside macros.
AST_MATCHER(IfStmt, isIfInMacro) {
return Node.getIfLoc().isMacroID() || Node.getEndLoc().isMacroID();
}
} // namespace
static const llvm::StringRef AlgorithmHeader("<algorithm>");
static bool minCondition(const BinaryOperator::Opcode Op, const Expr *CondLhs,
const Expr *CondRhs, const Expr *AssignLhs,
const Expr *AssignRhs, const ASTContext &Context) {
if ((Op == BO_LT || Op == BO_LE) &&
(tidy::utils::areStatementsIdentical(CondLhs, AssignRhs, Context) &&
tidy::utils::areStatementsIdentical(CondRhs, AssignLhs, Context)))
return true;
if ((Op == BO_GT || Op == BO_GE) &&
(tidy::utils::areStatementsIdentical(CondLhs, AssignLhs, Context) &&
tidy::utils::areStatementsIdentical(CondRhs, AssignRhs, Context)))
return true;
return false;
}
static bool maxCondition(const BinaryOperator::Opcode Op, const Expr *CondLhs,
const Expr *CondRhs, const Expr *AssignLhs,
const Expr *AssignRhs, const ASTContext &Context) {
if ((Op == BO_LT || Op == BO_LE) &&
(tidy::utils::areStatementsIdentical(CondLhs, AssignLhs, Context) &&
tidy::utils::areStatementsIdentical(CondRhs, AssignRhs, Context)))
return true;
if ((Op == BO_GT || Op == BO_GE) &&
(tidy::utils::areStatementsIdentical(CondLhs, AssignRhs, Context) &&
tidy::utils::areStatementsIdentical(CondRhs, AssignLhs, Context)))
return true;
return false;
}
static QualType getNonTemplateAlias(QualType QT) {
while (true) {
// cast to a TypedefType
if (const TypedefType *TT = dyn_cast<TypedefType>(QT)) {
// check if the typedef is a template and if it is dependent
if (!TT->getDecl()->getDescribedTemplate() &&
!TT->getDecl()->getDeclContext()->isDependentContext())
return QT;
QT = TT->getDecl()->getUnderlyingType();
}
// cast to elaborated type
else if (const ElaboratedType *ET = dyn_cast<ElaboratedType>(QT)) {
QT = ET->getNamedType();
} else {
break;
}
}
return QT;
}
static QualType getReplacementCastType(const Expr *CondLhs, const Expr *CondRhs,
QualType ComparedType) {
QualType LhsType = CondLhs->getType();
QualType RhsType = CondRhs->getType();
QualType LhsCanonicalType =
LhsType.getCanonicalType().getNonReferenceType().getUnqualifiedType();
QualType RhsCanonicalType =
RhsType.getCanonicalType().getNonReferenceType().getUnqualifiedType();
QualType GlobalImplicitCastType;
if (LhsCanonicalType != RhsCanonicalType) {
if (llvm::isa<IntegerLiteral>(CondRhs)) {
GlobalImplicitCastType = getNonTemplateAlias(LhsType);
} else if (llvm::isa<IntegerLiteral>(CondLhs)) {
GlobalImplicitCastType = getNonTemplateAlias(RhsType);
} else {
GlobalImplicitCastType = getNonTemplateAlias(ComparedType);
}
}
return GlobalImplicitCastType;
}
static std::string createReplacement(const Expr *CondLhs, const Expr *CondRhs,
const Expr *AssignLhs,
const SourceManager &Source,
const LangOptions &LO,
StringRef FunctionName,
const BinaryOperator *BO) {
const llvm::StringRef CondLhsStr = Lexer::getSourceText(
Source.getExpansionRange(CondLhs->getSourceRange()), Source, LO);
const llvm::StringRef CondRhsStr = Lexer::getSourceText(
Source.getExpansionRange(CondRhs->getSourceRange()), Source, LO);
const llvm::StringRef AssignLhsStr = Lexer::getSourceText(
Source.getExpansionRange(AssignLhs->getSourceRange()), Source, LO);
QualType GlobalImplicitCastType =
getReplacementCastType(CondLhs, CondRhs, BO->getLHS()->getType());
return (AssignLhsStr + " = " + FunctionName +
(!GlobalImplicitCastType.isNull()
? "<" + GlobalImplicitCastType.getAsString() + ">("
: "(") +
CondLhsStr + ", " + CondRhsStr + ");")
.str();
}
UseStdMinMaxCheck::UseStdMinMaxCheck(StringRef Name, ClangTidyContext *Context)
: ClangTidyCheck(Name, Context),
IncludeInserter(Options.getLocalOrGlobal("IncludeStyle",
utils::IncludeSorter::IS_LLVM),
areDiagsSelfContained()) {}
void UseStdMinMaxCheck::storeOptions(ClangTidyOptions::OptionMap &Opts) {
Options.store(Opts, "IncludeStyle", IncludeInserter.getStyle());
}
void UseStdMinMaxCheck::registerMatchers(MatchFinder *Finder) {
auto AssignOperator =
binaryOperator(hasOperatorName("="),
hasLHS(expr(unless(isTypeDependent())).bind("AssignLhs")),
hasRHS(expr(unless(isTypeDependent())).bind("AssignRhs")));
auto BinaryOperator =
binaryOperator(hasAnyOperatorName("<", ">", "<=", ">="),
hasLHS(expr(unless(isTypeDependent())).bind("CondLhs")),
hasRHS(expr(unless(isTypeDependent())).bind("CondRhs")))
.bind("binaryOp");
Finder->addMatcher(
ifStmt(stmt().bind("if"), unless(isIfInMacro()),
unless(hasElse(stmt())), // Ensure `if` has no `else`
hasCondition(BinaryOperator),
hasThen(
anyOf(stmt(AssignOperator),
compoundStmt(statementCountIs(1), has(AssignOperator)))),
hasParent(stmt(unless(ifStmt(hasElse(
equalsBoundNode("if"))))))), // Ensure `if` has no `else if`
this);
}
void UseStdMinMaxCheck::registerPPCallbacks(const SourceManager &SM,
Preprocessor *PP,
Preprocessor *ModuleExpanderPP) {
IncludeInserter.registerPreprocessor(PP);
}
void UseStdMinMaxCheck::check(const MatchFinder::MatchResult &Result) {
const auto *If = Result.Nodes.getNodeAs<IfStmt>("if");
const clang::LangOptions &LO = Result.Context->getLangOpts();
const auto *CondLhs = Result.Nodes.getNodeAs<Expr>("CondLhs");
const auto *CondRhs = Result.Nodes.getNodeAs<Expr>("CondRhs");
const auto *AssignLhs = Result.Nodes.getNodeAs<Expr>("AssignLhs");
const auto *AssignRhs = Result.Nodes.getNodeAs<Expr>("AssignRhs");
const auto *BinaryOp = Result.Nodes.getNodeAs<BinaryOperator>("binaryOp");
const clang::BinaryOperatorKind BinaryOpcode = BinaryOp->getOpcode();
const SourceLocation IfLocation = If->getIfLoc();
const SourceLocation ThenLocation = If->getEndLoc();
auto ReplaceAndDiagnose = [&](const llvm::StringRef FunctionName) {
const SourceManager &Source = *Result.SourceManager;
diag(IfLocation, "use `%0` instead of `%1`")
<< FunctionName << BinaryOp->getOpcodeStr()
<< FixItHint::CreateReplacement(
SourceRange(IfLocation, Lexer::getLocForEndOfToken(
ThenLocation, 0, Source, LO)),
createReplacement(CondLhs, CondRhs, AssignLhs, Source, LO,
FunctionName, BinaryOp))
<< IncludeInserter.createIncludeInsertion(
Source.getFileID(If->getBeginLoc()), AlgorithmHeader);
};
if (minCondition(BinaryOpcode, CondLhs, CondRhs, AssignLhs, AssignRhs,
(*Result.Context))) {
ReplaceAndDiagnose("std::min");
} else if (maxCondition(BinaryOpcode, CondLhs, CondRhs, AssignLhs, AssignRhs,
(*Result.Context))) {
ReplaceAndDiagnose("std::max");
}
}
} // namespace clang::tidy::readability
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