llvm-project/clang-tools-extra/clang-tidy/cppcoreguidelines/OwningMemoryCheck.cpp

396 lines
16 KiB
C++

//===--- OwningMemoryCheck.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 "OwningMemoryCheck.h"
#include "../utils/Matchers.h"
#include "../utils/OptionsUtils.h"
#include "clang/AST/ASTContext.h"
#include "clang/ASTMatchers/ASTMatchFinder.h"
#include <string>
#include <vector>
using namespace clang::ast_matchers;
using namespace clang::ast_matchers::internal;
namespace clang {
namespace tidy {
namespace cppcoreguidelines {
// FIXME: Copied from 'NoMallocCheck.cpp'. Has to be refactored into 'util' or
// something like that.
namespace {
Matcher<FunctionDecl> hasAnyListedName(const std::string &FunctionNames) {
const std::vector<std::string> NameList =
utils::options::parseStringList(FunctionNames);
return hasAnyName(std::vector<StringRef>(NameList.begin(), NameList.end()));
}
} // namespace
void OwningMemoryCheck::storeOptions(ClangTidyOptions::OptionMap &Opts) {
Options.store(Opts, "LegacyResourceProducers", LegacyResourceProducers);
Options.store(Opts, "LegacyResourceConsumers", LegacyResourceConsumers);
}
/// Match common cases, where the owner semantic is relevant, like function
/// calls, delete expressions and others.
void OwningMemoryCheck::registerMatchers(MatchFinder *Finder) {
const auto OwnerDecl = typeAliasTemplateDecl(hasName("::gsl::owner"));
const auto IsOwnerType = hasType(OwnerDecl);
const auto LegacyCreatorFunctions = hasAnyListedName(LegacyResourceProducers);
const auto LegacyConsumerFunctions =
hasAnyListedName(LegacyResourceConsumers);
// Legacy functions that are use for resource management but cannot be
// updated to use `gsl::owner<>`, like standard C memory management.
const auto CreatesLegacyOwner =
callExpr(callee(functionDecl(LegacyCreatorFunctions)));
// C-style functions like `::malloc()` sometimes create owners as void*
// which is expected to be cast to the correct type in C++. This case
// must be catched explicitly.
const auto LegacyOwnerCast =
castExpr(hasSourceExpression(CreatesLegacyOwner));
// Functions that do manual resource management but cannot be updated to use
// owner. Best example is `::free()`.
const auto LegacyOwnerConsumers = functionDecl(LegacyConsumerFunctions);
const auto CreatesOwner =
anyOf(cxxNewExpr(),
callExpr(callee(
functionDecl(returns(qualType(hasDeclaration(OwnerDecl)))))),
CreatesLegacyOwner, LegacyOwnerCast);
const auto ConsideredOwner = eachOf(IsOwnerType, CreatesOwner);
// Find delete expressions that delete non-owners.
Finder->addMatcher(
traverse(TK_AsIs,
cxxDeleteExpr(hasDescendant(declRefExpr(unless(ConsideredOwner))
.bind("deleted_variable")))
.bind("delete_expr")),
this);
// Ignoring the implicit casts is vital because the legacy owners do not work
// with the 'owner<>' annotation and therefore always implicitly cast to the
// legacy type (even 'void *').
//
// Furthermore, legacy owner functions are assumed to use raw pointers for
// resources. This check assumes that all pointer arguments of a legacy
// functions shall be 'gsl::owner<>'.
Finder->addMatcher(
traverse(TK_AsIs, callExpr(callee(LegacyOwnerConsumers),
hasAnyArgument(expr(
unless(ignoringImpCasts(ConsideredOwner)),
hasType(pointerType()))))
.bind("legacy_consumer")),
this);
// Matching assignment to owners, with the rhs not being an owner nor creating
// one.
Finder->addMatcher(
traverse(TK_AsIs,
binaryOperator(isAssignmentOperator(), hasLHS(IsOwnerType),
hasRHS(unless(ConsideredOwner)))
.bind("owner_assignment")),
this);
// Matching initialization of owners with non-owners, nor creating owners.
Finder->addMatcher(
traverse(TK_AsIs,
namedDecl(
varDecl(hasInitializer(unless(ConsideredOwner)), IsOwnerType)
.bind("owner_initialization"))),
this);
const auto HasConstructorInitializerForOwner =
has(cxxConstructorDecl(forEachConstructorInitializer(
cxxCtorInitializer(
isMemberInitializer(), forField(IsOwnerType),
withInitializer(
// Avoid templatesdeclaration with
// excluding parenListExpr.
allOf(unless(ConsideredOwner), unless(parenListExpr()))))
.bind("owner_member_initializer"))));
// Match class member initialization that expects owners, but does not get
// them.
Finder->addMatcher(
traverse(TK_AsIs, cxxRecordDecl(HasConstructorInitializerForOwner)),
this);
// Matching on assignment operations where the RHS is a newly created owner,
// but the LHS is not an owner.
Finder->addMatcher(binaryOperator(isAssignmentOperator(),
hasLHS(unless(IsOwnerType)),
hasRHS(CreatesOwner))
.bind("bad_owner_creation_assignment"),
this);
// Matching on initialization operations where the initial value is a newly
// created owner, but the LHS is not an owner.
Finder->addMatcher(
traverse(
TK_AsIs,
namedDecl(
varDecl(eachOf(allOf(hasInitializer(CreatesOwner),
unless(IsOwnerType)),
allOf(hasInitializer(ConsideredOwner),
hasType(autoType().bind("deduced_type")))))
.bind("bad_owner_creation_variable"))),
this);
// Match on all function calls that expect owners as arguments, but didn't
// get them.
Finder->addMatcher(
callExpr(forEachArgumentWithParam(
expr(unless(ConsideredOwner)).bind("expected_owner_argument"),
parmVarDecl(IsOwnerType))),
this);
// Matching for function calls where one argument is a created owner, but the
// parameter type is not an owner.
Finder->addMatcher(callExpr(forEachArgumentWithParam(
expr(CreatesOwner).bind("bad_owner_creation_argument"),
parmVarDecl(unless(IsOwnerType))
.bind("bad_owner_creation_parameter"))),
this);
// Matching on functions, that return an owner/resource, but don't declare
// their return type as owner.
Finder->addMatcher(
functionDecl(hasDescendant(returnStmt(hasReturnValue(ConsideredOwner))
.bind("bad_owner_return")),
unless(returns(qualType(hasDeclaration(OwnerDecl)))))
.bind("function_decl"),
this);
// Match on classes that have an owner as member, but don't declare a
// destructor to properly release the owner.
Finder->addMatcher(
cxxRecordDecl(
has(fieldDecl(IsOwnerType).bind("undestructed_owner_member")),
anyOf(unless(has(cxxDestructorDecl())),
has(cxxDestructorDecl(anyOf(isDefaulted(), isDeleted())))))
.bind("non_destructor_class"),
this);
}
void OwningMemoryCheck::check(const MatchFinder::MatchResult &Result) {
const auto &Nodes = Result.Nodes;
bool CheckExecuted = false;
CheckExecuted |= handleDeletion(Nodes);
CheckExecuted |= handleLegacyConsumers(Nodes);
CheckExecuted |= handleExpectedOwner(Nodes);
CheckExecuted |= handleAssignmentAndInit(Nodes);
CheckExecuted |= handleAssignmentFromNewOwner(Nodes);
CheckExecuted |= handleReturnValues(Nodes);
CheckExecuted |= handleOwnerMembers(Nodes);
assert(CheckExecuted &&
"None of the subroutines executed, logic error in matcher!");
}
bool OwningMemoryCheck::handleDeletion(const BoundNodes &Nodes) {
// Result of delete matchers.
const auto *DeleteStmt = Nodes.getNodeAs<CXXDeleteExpr>("delete_expr");
const auto *DeletedVariable =
Nodes.getNodeAs<DeclRefExpr>("deleted_variable");
// Deletion of non-owners, with `delete variable;`
if (DeleteStmt) {
diag(DeleteStmt->getBeginLoc(),
"deleting a pointer through a type that is "
"not marked 'gsl::owner<>'; consider using a "
"smart pointer instead")
<< DeletedVariable->getSourceRange();
// FIXME: The declaration of the variable that was deleted can be
// rewritten.
const ValueDecl *Decl = DeletedVariable->getDecl();
diag(Decl->getBeginLoc(), "variable declared here", DiagnosticIDs::Note)
<< Decl->getSourceRange();
return true;
}
return false;
}
bool OwningMemoryCheck::handleLegacyConsumers(const BoundNodes &Nodes) {
// Result of matching for legacy consumer-functions like `::free()`.
const auto *LegacyConsumer = Nodes.getNodeAs<CallExpr>("legacy_consumer");
// FIXME: `freopen` should be handled separately because it takes the filename
// as a pointer, which should not be an owner. The argument that is an owner
// is known and the false positive coming from the filename can be avoided.
if (LegacyConsumer) {
diag(LegacyConsumer->getBeginLoc(),
"calling legacy resource function without passing a 'gsl::owner<>'")
<< LegacyConsumer->getSourceRange();
return true;
}
return false;
}
bool OwningMemoryCheck::handleExpectedOwner(const BoundNodes &Nodes) {
// Result of function call matchers.
const auto *ExpectedOwner = Nodes.getNodeAs<Expr>("expected_owner_argument");
// Expected function argument to be owner.
if (ExpectedOwner) {
diag(ExpectedOwner->getBeginLoc(),
"expected argument of type 'gsl::owner<>'; got %0")
<< ExpectedOwner->getType() << ExpectedOwner->getSourceRange();
return true;
}
return false;
}
/// Assignment and initialization of owner variables.
bool OwningMemoryCheck::handleAssignmentAndInit(const BoundNodes &Nodes) {
const auto *OwnerAssignment =
Nodes.getNodeAs<BinaryOperator>("owner_assignment");
const auto *OwnerInitialization =
Nodes.getNodeAs<VarDecl>("owner_initialization");
const auto *OwnerInitializer =
Nodes.getNodeAs<CXXCtorInitializer>("owner_member_initializer");
// Assignments to owners.
if (OwnerAssignment) {
diag(OwnerAssignment->getBeginLoc(),
"expected assignment source to be of type 'gsl::owner<>'; got %0")
<< OwnerAssignment->getRHS()->getType()
<< OwnerAssignment->getSourceRange();
return true;
}
// Initialization of owners.
if (OwnerInitialization) {
diag(OwnerInitialization->getBeginLoc(),
"expected initialization with value of type 'gsl::owner<>'; got %0")
<< OwnerInitialization->getAnyInitializer()->getType()
<< OwnerInitialization->getSourceRange();
return true;
}
// Initializer of class constructors that initialize owners.
if (OwnerInitializer) {
diag(OwnerInitializer->getSourceLocation(),
"expected initialization of owner member variable with value of type "
"'gsl::owner<>'; got %0")
// FIXME: the expression from getInit has type 'void', but the type
// of the supplied argument would be of interest.
<< OwnerInitializer->getInit()->getType()
<< OwnerInitializer->getSourceRange();
return true;
}
return false;
}
/// Problematic assignment and initializations, since the assigned value is a
/// newly created owner.
bool OwningMemoryCheck::handleAssignmentFromNewOwner(const BoundNodes &Nodes) {
const auto *BadOwnerAssignment =
Nodes.getNodeAs<BinaryOperator>("bad_owner_creation_assignment");
const auto *BadOwnerInitialization =
Nodes.getNodeAs<VarDecl>("bad_owner_creation_variable");
const auto *BadOwnerArgument =
Nodes.getNodeAs<Expr>("bad_owner_creation_argument");
const auto *BadOwnerParameter =
Nodes.getNodeAs<ParmVarDecl>("bad_owner_creation_parameter");
// Bad assignments to non-owners, where the RHS is a newly created owner.
if (BadOwnerAssignment) {
diag(BadOwnerAssignment->getBeginLoc(),
"assigning newly created 'gsl::owner<>' to non-owner %0")
<< BadOwnerAssignment->getLHS()->getType()
<< BadOwnerAssignment->getSourceRange();
return true;
}
// Bad initialization of non-owners, where the RHS is a newly created owner.
if (BadOwnerInitialization) {
diag(BadOwnerInitialization->getBeginLoc(),
"initializing non-owner %0 with a newly created 'gsl::owner<>'")
<< BadOwnerInitialization->getType()
<< BadOwnerInitialization->getSourceRange();
// FIXME: FixitHint to rewrite the type of the initialized variable
// as 'gsl::owner<OriginalType>'
// If the type of the variable was deduced, the wrapping owner typedef is
// eliminated, therefore the check emits a special note for that case.
if (Nodes.getNodeAs<AutoType>("deduced_type")) {
diag(BadOwnerInitialization->getBeginLoc(),
"type deduction did not result in an owner", DiagnosticIDs::Note);
}
return true;
}
// Function call, where one arguments is a newly created owner, but the
// parameter type is not.
if (BadOwnerArgument) {
assert(BadOwnerParameter &&
"parameter for the problematic argument not found");
diag(BadOwnerArgument->getBeginLoc(), "initializing non-owner argument of "
"type %0 with a newly created "
"'gsl::owner<>'")
<< BadOwnerParameter->getType() << BadOwnerArgument->getSourceRange();
return true;
}
return false;
}
bool OwningMemoryCheck::handleReturnValues(const BoundNodes &Nodes) {
// Function return statements, that are owners/resources, but the function
// declaration does not declare its return value as owner.
const auto *BadReturnType = Nodes.getNodeAs<ReturnStmt>("bad_owner_return");
const auto *Function = Nodes.getNodeAs<FunctionDecl>("function_decl");
// Function return values, that should be owners but aren't.
if (BadReturnType) {
// The returned value is a resource or variable that was not annotated with
// owner<> and the function return type is not owner<>.
diag(BadReturnType->getBeginLoc(),
"returning a newly created resource of "
"type %0 or 'gsl::owner<>' from a "
"function whose return type is not 'gsl::owner<>'")
<< Function->getReturnType() << BadReturnType->getSourceRange();
// FIXME: Rewrite the return type as 'gsl::owner<OriginalType>'
return true;
}
return false;
}
bool OwningMemoryCheck::handleOwnerMembers(const BoundNodes &Nodes) {
// Classes, that have owners as member, but do not declare destructors
// accordingly.
const auto *BadClass = Nodes.getNodeAs<CXXRecordDecl>("non_destructor_class");
// Classes, that contains owners, but do not declare destructors.
if (BadClass) {
const auto *DeclaredOwnerMember =
Nodes.getNodeAs<FieldDecl>("undestructed_owner_member");
assert(DeclaredOwnerMember &&
"match on class with bad destructor but without a declared owner");
diag(DeclaredOwnerMember->getBeginLoc(),
"member variable of type 'gsl::owner<>' requires the class %0 to "
"implement a destructor to release the owned resource")
<< BadClass;
return true;
}
return false;
}
} // namespace cppcoreguidelines
} // namespace tidy
} // namespace clang