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-rw-r--r--third_party/libwebrtc/tools/clang/plugins/FindBadConstructs.cpp435
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diff --git a/third_party/libwebrtc/tools/clang/plugins/FindBadConstructs.cpp b/third_party/libwebrtc/tools/clang/plugins/FindBadConstructs.cpp
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-// Copyright (c) 2012 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-// This file defines a bunch of recurring problems in the Chromium C++ code.
-//
-// Checks that are implemented:
-// - Constructors/Destructors should not be inlined if they are of a complex
-// class type.
-// - Missing "virtual" keywords on methods that should be virtual.
-// - Non-annotated overriding virtual methods.
-// - Virtual methods with nonempty implementations in their headers.
-// - Classes that derive from base::RefCounted / base::RefCountedThreadSafe
-// should have protected or private destructors.
-
-#include "clang/Frontend/FrontendPluginRegistry.h"
-#include "clang/AST/ASTConsumer.h"
-#include "clang/AST/AST.h"
-#include "clang/AST/CXXInheritance.h"
-#include "clang/AST/TypeLoc.h"
-#include "clang/Basic/SourceManager.h"
-#include "clang/Frontend/CompilerInstance.h"
-#include "llvm/Support/raw_ostream.h"
-
-#include "ChromeClassTester.h"
-
-using namespace clang;
-
-namespace {
-
-bool TypeHasNonTrivialDtor(const Type* type) {
- if (const CXXRecordDecl* cxx_r = type->getCXXRecordDeclForPointerType())
- return cxx_r->hasTrivialDestructor();
-
- return false;
-}
-
-// Returns the underlying Type for |type| by expanding typedefs and removing
-// any namespace qualifiers.
-const Type* UnwrapType(const Type* type) {
- if (const ElaboratedType* elaborated = dyn_cast<ElaboratedType>(type))
- return UnwrapType(elaborated->getNamedType().getTypePtr());
- if (const TypedefType* typedefed = dyn_cast<TypedefType>(type))
- return UnwrapType(typedefed->desugar().getTypePtr());
- return type;
-}
-
-// Searches for constructs that we know we don't want in the Chromium code base.
-class FindBadConstructsConsumer : public ChromeClassTester {
- public:
- FindBadConstructsConsumer(CompilerInstance& instance,
- bool check_refcounted_dtors,
- bool check_virtuals_in_implementations)
- : ChromeClassTester(instance),
- check_refcounted_dtors_(check_refcounted_dtors),
- check_virtuals_in_implementations_(check_virtuals_in_implementations) {
- }
-
- virtual void CheckChromeClass(SourceLocation record_location,
- CXXRecordDecl* record) {
- bool implementation_file = InImplementationFile(record_location);
-
- if (!implementation_file) {
- // Only check for "heavy" constructors/destructors in header files;
- // within implementation files, there is no performance cost.
- CheckCtorDtorWeight(record_location, record);
- }
-
- if (!implementation_file || check_virtuals_in_implementations_) {
- bool warn_on_inline_bodies = !implementation_file;
-
- // Check that all virtual methods are marked accordingly with both
- // virtual and OVERRIDE.
- CheckVirtualMethods(record_location, record, warn_on_inline_bodies);
- }
-
- if (check_refcounted_dtors_)
- CheckRefCountedDtors(record_location, record);
- }
-
- private:
- bool check_refcounted_dtors_;
- bool check_virtuals_in_implementations_;
-
- // Returns true if |base| specifies one of the Chromium reference counted
- // classes (base::RefCounted / base::RefCountedThreadSafe). |user_data| is
- // ignored.
- static bool IsRefCountedCallback(const CXXBaseSpecifier* base,
- CXXBasePath& path,
- void* user_data) {
- FindBadConstructsConsumer* self =
- static_cast<FindBadConstructsConsumer*>(user_data);
-
- const TemplateSpecializationType* base_type =
- dyn_cast<TemplateSpecializationType>(
- UnwrapType(base->getType().getTypePtr()));
- if (!base_type) {
- // Base-most definition is not a template, so this cannot derive from
- // base::RefCounted. However, it may still be possible to use with a
- // scoped_refptr<> and support ref-counting, so this is not a perfect
- // guarantee of safety.
- return false;
- }
-
- TemplateName name = base_type->getTemplateName();
- if (TemplateDecl* decl = name.getAsTemplateDecl()) {
- std::string base_name = decl->getNameAsString();
-
- // Check for both base::RefCounted and base::RefCountedThreadSafe.
- if (base_name.compare(0, 10, "RefCounted") == 0 &&
- self->GetNamespace(decl) == "base") {
- return true;
- }
- }
- return false;
- }
-
- // Prints errors if the destructor of a RefCounted class is public.
- void CheckRefCountedDtors(SourceLocation record_location,
- CXXRecordDecl* record) {
- // Skip anonymous structs.
- if (record->getIdentifier() == NULL)
- return;
-
- CXXBasePaths paths;
- if (!record->lookupInBases(
- &FindBadConstructsConsumer::IsRefCountedCallback, this, paths)) {
- return; // Class does not derive from a ref-counted base class.
- }
-
- if (!record->hasUserDeclaredDestructor()) {
- emitWarning(
- record_location,
- "Classes that are ref-counted should have explicit "
- "destructors that are protected or private.");
- } else if (CXXDestructorDecl* dtor = record->getDestructor()) {
- if (dtor->getAccess() == AS_public) {
- emitWarning(
- dtor->getInnerLocStart(),
- "Classes that are ref-counted should not have "
- "public destructors.");
- }
- }
- }
-
- // Prints errors if the constructor/destructor weight is too heavy.
- void CheckCtorDtorWeight(SourceLocation record_location,
- CXXRecordDecl* record) {
- // We don't handle anonymous structs. If this record doesn't have a
- // name, it's of the form:
- //
- // struct {
- // ...
- // } name_;
- if (record->getIdentifier() == NULL)
- return;
-
- // Count the number of templated base classes as a feature of whether the
- // destructor can be inlined.
- int templated_base_classes = 0;
- for (CXXRecordDecl::base_class_const_iterator it = record->bases_begin();
- it != record->bases_end(); ++it) {
- if (it->getTypeSourceInfo()->getTypeLoc().getTypeLocClass() ==
- TypeLoc::TemplateSpecialization) {
- ++templated_base_classes;
- }
- }
-
- // Count the number of trivial and non-trivial member variables.
- int trivial_member = 0;
- int non_trivial_member = 0;
- int templated_non_trivial_member = 0;
- for (RecordDecl::field_iterator it = record->field_begin();
- it != record->field_end(); ++it) {
- CountType(it->getType().getTypePtr(),
- &trivial_member,
- &non_trivial_member,
- &templated_non_trivial_member);
- }
-
- // Check to see if we need to ban inlined/synthesized constructors. Note
- // that the cutoffs here are kind of arbitrary. Scores over 10 break.
- int dtor_score = 0;
- // Deriving from a templated base class shouldn't be enough to trigger
- // the ctor warning, but if you do *anything* else, it should.
- //
- // TODO(erg): This is motivated by templated base classes that don't have
- // any data members. Somehow detect when templated base classes have data
- // members and treat them differently.
- dtor_score += templated_base_classes * 9;
- // Instantiating a template is an insta-hit.
- dtor_score += templated_non_trivial_member * 10;
- // The fourth normal class member should trigger the warning.
- dtor_score += non_trivial_member * 3;
-
- int ctor_score = dtor_score;
- // You should be able to have 9 ints before we warn you.
- ctor_score += trivial_member;
-
- if (ctor_score >= 10) {
- if (!record->hasUserDeclaredConstructor()) {
- emitWarning(record_location,
- "Complex class/struct needs an explicit out-of-line "
- "constructor.");
- } else {
- // Iterate across all the constructors in this file and yell if we
- // find one that tries to be inline.
- for (CXXRecordDecl::ctor_iterator it = record->ctor_begin();
- it != record->ctor_end(); ++it) {
- if (it->hasInlineBody()) {
- if (it->isCopyConstructor() &&
- !record->hasUserDeclaredCopyConstructor()) {
- emitWarning(record_location,
- "Complex class/struct needs an explicit out-of-line "
- "copy constructor.");
- } else {
- emitWarning(it->getInnerLocStart(),
- "Complex constructor has an inlined body.");
- }
- }
- }
- }
- }
-
- // The destructor side is equivalent except that we don't check for
- // trivial members; 20 ints don't need a destructor.
- if (dtor_score >= 10 && !record->hasTrivialDestructor()) {
- if (!record->hasUserDeclaredDestructor()) {
- emitWarning(
- record_location,
- "Complex class/struct needs an explicit out-of-line "
- "destructor.");
- } else if (CXXDestructorDecl* dtor = record->getDestructor()) {
- if (dtor->hasInlineBody()) {
- emitWarning(dtor->getInnerLocStart(),
- "Complex destructor has an inline body.");
- }
- }
- }
- }
-
- void CheckVirtualMethod(const CXXMethodDecl* method,
- bool warn_on_inline_bodies) {
- if (!method->isVirtual())
- return;
-
- if (!method->isVirtualAsWritten()) {
- SourceLocation loc = method->getTypeSpecStartLoc();
- if (isa<CXXDestructorDecl>(method))
- loc = method->getInnerLocStart();
- emitWarning(loc, "Overriding method must have \"virtual\" keyword.");
- }
-
- // Virtual methods should not have inline definitions beyond "{}". This
- // only matters for header files.
- if (warn_on_inline_bodies && method->hasBody() &&
- method->hasInlineBody()) {
- if (CompoundStmt* cs = dyn_cast<CompoundStmt>(method->getBody())) {
- if (cs->size()) {
- emitWarning(
- cs->getLBracLoc(),
- "virtual methods with non-empty bodies shouldn't be "
- "declared inline.");
- }
- }
- }
- }
-
- bool InTestingNamespace(const Decl* record) {
- return GetNamespace(record).find("testing") != std::string::npos;
- }
-
- bool IsMethodInBannedNamespace(const CXXMethodDecl* method) {
- if (InBannedNamespace(method))
- return true;
- for (CXXMethodDecl::method_iterator i = method->begin_overridden_methods();
- i != method->end_overridden_methods();
- ++i) {
- const CXXMethodDecl* overridden = *i;
- if (IsMethodInBannedNamespace(overridden))
- return true;
- }
-
- return false;
- }
-
- void CheckOverriddenMethod(const CXXMethodDecl* method) {
- if (!method->size_overridden_methods() || method->getAttr<OverrideAttr>())
- return;
-
- if (isa<CXXDestructorDecl>(method) || method->isPure())
- return;
-
- if (IsMethodInBannedNamespace(method))
- return;
-
- SourceLocation loc = method->getTypeSpecStartLoc();
- emitWarning(loc, "Overriding method must be marked with OVERRIDE.");
- }
-
- // Makes sure there is a "virtual" keyword on virtual methods.
- //
- // Gmock objects trigger these for each MOCK_BLAH() macro used. So we have a
- // trick to get around that. If a class has member variables whose types are
- // in the "testing" namespace (which is how gmock works behind the scenes),
- // there's a really high chance we won't care about these errors
- void CheckVirtualMethods(SourceLocation record_location,
- CXXRecordDecl* record,
- bool warn_on_inline_bodies) {
- for (CXXRecordDecl::field_iterator it = record->field_begin();
- it != record->field_end(); ++it) {
- CXXRecordDecl* record_type =
- it->getTypeSourceInfo()->getTypeLoc().getTypePtr()->
- getAsCXXRecordDecl();
- if (record_type) {
- if (InTestingNamespace(record_type)) {
- return;
- }
- }
- }
-
- for (CXXRecordDecl::method_iterator it = record->method_begin();
- it != record->method_end(); ++it) {
- if (it->isCopyAssignmentOperator() || isa<CXXConstructorDecl>(*it)) {
- // Ignore constructors and assignment operators.
- } else if (isa<CXXDestructorDecl>(*it) &&
- !record->hasUserDeclaredDestructor()) {
- // Ignore non-user-declared destructors.
- } else {
- CheckVirtualMethod(*it, warn_on_inline_bodies);
- CheckOverriddenMethod(*it);
- }
- }
- }
-
- void CountType(const Type* type,
- int* trivial_member,
- int* non_trivial_member,
- int* templated_non_trivial_member) {
- switch (type->getTypeClass()) {
- case Type::Record: {
- // Simplifying; the whole class isn't trivial if the dtor is, but
- // we use this as a signal about complexity.
- if (TypeHasNonTrivialDtor(type))
- (*trivial_member)++;
- else
- (*non_trivial_member)++;
- break;
- }
- case Type::TemplateSpecialization: {
- TemplateName name =
- dyn_cast<TemplateSpecializationType>(type)->getTemplateName();
- bool whitelisted_template = false;
-
- // HACK: I'm at a loss about how to get the syntax checker to get
- // whether a template is exterened or not. For the first pass here,
- // just do retarded string comparisons.
- if (TemplateDecl* decl = name.getAsTemplateDecl()) {
- std::string base_name = decl->getNameAsString();
- if (base_name == "basic_string")
- whitelisted_template = true;
- }
-
- if (whitelisted_template)
- (*non_trivial_member)++;
- else
- (*templated_non_trivial_member)++;
- break;
- }
- case Type::Elaborated: {
- CountType(
- dyn_cast<ElaboratedType>(type)->getNamedType().getTypePtr(),
- trivial_member, non_trivial_member, templated_non_trivial_member);
- break;
- }
- case Type::Typedef: {
- while (const TypedefType* TT = dyn_cast<TypedefType>(type)) {
- type = TT->getDecl()->getUnderlyingType().getTypePtr();
- }
- CountType(type, trivial_member, non_trivial_member,
- templated_non_trivial_member);
- break;
- }
- default: {
- // Stupid assumption: anything we see that isn't the above is one of
- // the 20 integer types.
- (*trivial_member)++;
- break;
- }
- }
- }
-};
-
-class FindBadConstructsAction : public PluginASTAction {
- public:
- FindBadConstructsAction()
- : check_refcounted_dtors_(true),
- check_virtuals_in_implementations_(true) {
- }
-
- protected:
- // Overridden from PluginASTAction:
- virtual ASTConsumer* CreateASTConsumer(CompilerInstance& instance,
- llvm::StringRef ref) {
- return new FindBadConstructsConsumer(
- instance, check_refcounted_dtors_, check_virtuals_in_implementations_);
- }
-
- virtual bool ParseArgs(const CompilerInstance& instance,
- const std::vector<std::string>& args) {
- bool parsed = true;
-
- for (size_t i = 0; i < args.size() && parsed; ++i) {
- if (args[i] == "skip-refcounted-dtors") {
- check_refcounted_dtors_ = false;
- } else if (args[i] == "skip-virtuals-in-implementations") {
- check_virtuals_in_implementations_ = false;
- } else {
- parsed = false;
- llvm::errs() << "Unknown argument: " << args[i] << "\n";
- }
- }
-
- return parsed;
- }
-
- private:
- bool check_refcounted_dtors_;
- bool check_virtuals_in_implementations_;
-};
-
-} // namespace
-
-static FrontendPluginRegistry::Add<FindBadConstructsAction>
-X("find-bad-constructs", "Finds bad C++ constructs");