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//===--- ProTypeMemberInitCheck.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 "ProTypeMemberInitCheck.h"
#include "../utils/LexerUtils.h"
#include "clang/AST/ASTContext.h"
#include "clang/ASTMatchers/ASTMatchFinder.h"
#include "clang/Lex/Lexer.h"
#include "llvm/ADT/SmallPtrSet.h"
using namespace clang::ast_matchers;
using llvm::SmallPtrSet;
using llvm::SmallPtrSetImpl;
namespace clang {
namespace tidy {
namespace cppcoreguidelines {
namespace {
AST_MATCHER(CXXConstructorDecl, isUserProvided) {
return Node.isUserProvided();
}
static void
fieldsRequiringInit(const RecordDecl::field_range &Fields,
SmallPtrSetImpl<const FieldDecl *> &FieldsToInit) {
for (const FieldDecl *F : Fields) {
QualType Type = F->getType();
if (Type->isPointerType() || Type->isBuiltinType())
FieldsToInit.insert(F);
}
}
void removeFieldsInitializedInBody(
const Stmt &Stmt, ASTContext &Context,
SmallPtrSetImpl<const FieldDecl *> &FieldDecls) {
auto Matches =
match(findAll(binaryOperator(
hasOperatorName("="),
hasLHS(memberExpr(member(fieldDecl().bind("fieldDecl")))))),
Stmt, Context);
for (const auto &Match : Matches)
FieldDecls.erase(Match.getNodeAs<FieldDecl>("fieldDecl"));
}
// Creates comma separated list of fields requiring initialization in order of
// declaration.
std::string toCommaSeparatedString(
const RecordDecl::field_range &FieldRange,
const SmallPtrSetImpl<const FieldDecl *> &FieldsRequiringInit) {
std::string List;
llvm::raw_string_ostream Stream(List);
size_t AddedFields = 0;
for (const FieldDecl *Field : FieldRange) {
if (FieldsRequiringInit.count(Field) > 0) {
Stream << Field->getName();
if (++AddedFields < FieldsRequiringInit.size())
Stream << ", ";
}
}
return Stream.str();
}
// Contains all fields in correct order that need to be inserted at the same
// location for pre C++11.
// There are 3 kinds of insertions:
// 1. The fields are inserted after an existing CXXCtorInitializer stored in
// InitializerBefore. This will be the case whenever there is a written
// initializer before the fields available.
// 2. The fields are inserted before the first existing initializer stored in
// InitializerAfter.
// 3. There are no written initializers and the fields will be inserted before
// the constructor's body creating a new initializer list including the ':'.
struct FieldsInsertion {
const CXXCtorInitializer *InitializerBefore;
const CXXCtorInitializer *InitializerAfter;
SmallVector<const FieldDecl *, 4> Fields;
SourceLocation getLocation(const ASTContext &Context,
const CXXConstructorDecl &Constructor) const {
if (InitializerBefore != nullptr) {
return Lexer::getLocForEndOfToken(InitializerBefore->getRParenLoc(), 0,
Context.getSourceManager(),
Context.getLangOpts());
}
auto StartLocation = InitializerAfter != nullptr
? InitializerAfter->getSourceRange().getBegin()
: Constructor.getBody()->getLocStart();
auto Token =
lexer_utils::getPreviousNonCommentToken(Context, StartLocation);
return Lexer::getLocForEndOfToken(Token.getLocation(), 0,
Context.getSourceManager(),
Context.getLangOpts());
}
std::string codeToInsert() const {
assert(!Fields.empty() && "No fields to insert");
std::string Code;
llvm::raw_string_ostream Stream(Code);
// Code will be inserted before the first written initializer after ':',
// append commas.
if (InitializerAfter != nullptr) {
for (const auto *Field : Fields)
Stream << " " << Field->getName() << "(),";
} else {
// The full initializer list is created, add extra space after
// constructor's rparens.
if (InitializerBefore == nullptr)
Stream << " ";
for (const auto *Field : Fields)
Stream << ", " << Field->getName() << "()";
}
Stream.flush();
// The initializer list is created, replace leading comma with colon.
if (InitializerBefore == nullptr && InitializerAfter == nullptr)
Code[1] = ':';
return Code;
}
};
SmallVector<FieldsInsertion, 16> computeInsertions(
const CXXConstructorDecl::init_const_range &Inits,
const RecordDecl::field_range &Fields,
const SmallPtrSetImpl<const FieldDecl *> &FieldsRequiringInit) {
// Find last written non-member initializer or null.
const CXXCtorInitializer *LastWrittenNonMemberInit = nullptr;
for (const CXXCtorInitializer *Init : Inits) {
if (Init->isWritten() && !Init->isMemberInitializer())
LastWrittenNonMemberInit = Init;
}
SmallVector<FieldsInsertion, 16> OrderedFields;
OrderedFields.push_back({LastWrittenNonMemberInit, nullptr, {}});
auto CurrentField = Fields.begin();
for (const CXXCtorInitializer *Init : Inits) {
if (Init->isWritten() && Init->isMemberInitializer()) {
const FieldDecl *MemberField = Init->getMember();
// Add all fields between current field and this member field the previous
// FieldsInsertion if the field requires initialization.
for (; CurrentField != Fields.end() && *CurrentField != MemberField;
++CurrentField) {
if (FieldsRequiringInit.count(*CurrentField) > 0)
OrderedFields.back().Fields.push_back(*CurrentField);
}
// If this is the first written member initializer and there was no
// written non-member initializer set this initializer as
// InitializerAfter.
if (OrderedFields.size() == 1 &&
OrderedFields.back().InitializerBefore == nullptr)
OrderedFields.back().InitializerAfter = Init;
OrderedFields.push_back({Init, nullptr, {}});
}
}
// Add remaining fields that require initialization to last FieldsInsertion.
for (; CurrentField != Fields.end(); ++CurrentField) {
if (FieldsRequiringInit.count(*CurrentField) > 0)
OrderedFields.back().Fields.push_back(*CurrentField);
}
return OrderedFields;
}
} // namespace
void ProTypeMemberInitCheck::registerMatchers(MatchFinder *Finder) {
Finder->addMatcher(cxxConstructorDecl(isDefinition(), isUserProvided(),
unless(isInstantiated()))
.bind("ctor"),
this);
}
void ProTypeMemberInitCheck::check(const MatchFinder::MatchResult &Result) {
const auto *Ctor = Result.Nodes.getNodeAs<CXXConstructorDecl>("ctor");
const auto &MemberFields = Ctor->getParent()->fields();
// Skip declarations delayed by late template parsing without a body.
const Stmt *Body = Ctor->getBody();
if (!Body)
return;
SmallPtrSet<const FieldDecl *, 16> FieldsToInit;
fieldsRequiringInit(MemberFields, FieldsToInit);
if (FieldsToInit.empty())
return;
for (CXXCtorInitializer *Init : Ctor->inits()) {
// Return early if this constructor simply delegates to another constructor
// in the same class.
if (Init->isDelegatingInitializer())
return;
if (!Init->isMemberInitializer())
continue;
FieldsToInit.erase(Init->getMember());
}
removeFieldsInitializedInBody(*Body, *Result.Context, FieldsToInit);
if (FieldsToInit.empty())
return;
DiagnosticBuilder Diag =
diag(Ctor->getLocStart(),
"constructor does not initialize these built-in/pointer fields: %0")
<< toCommaSeparatedString(MemberFields, FieldsToInit);
// Do not propose fixes in macros since we cannot place them correctly.
if (Ctor->getLocStart().isMacroID())
return;
// For C+11 use in-class initialization which covers all future constructors
// as well.
if (Result.Context->getLangOpts().CPlusPlus11) {
for (const auto *Field : FieldsToInit) {
Diag << FixItHint::CreateInsertion(
Lexer::getLocForEndOfToken(Field->getSourceRange().getEnd(), 0,
Result.Context->getSourceManager(),
Result.Context->getLangOpts()),
"{}");
}
return;
}
for (const auto &FieldsInsertion :
computeInsertions(Ctor->inits(), MemberFields, FieldsToInit)) {
if (!FieldsInsertion.Fields.empty())
Diag << FixItHint::CreateInsertion(
FieldsInsertion.getLocation(*Result.Context, *Ctor),
FieldsInsertion.codeToInsert());
}
}
} // namespace cppcoreguidelines
} // namespace tidy
} // namespace clang
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