juliehockett updated this revision to Diff 124662.
juliehockett marked 6 inline comments as done.
https://reviews.llvm.org/D40580
Files:
clang-tidy/fuchsia/CMakeLists.txt
clang-tidy/fuchsia/FuchsiaTidyModule.cpp
clang-tidy/fuchsia/MultipleInheritanceCheck.cpp
clang-tidy/fuchsia/MultipleInheritanceCheck.h
docs/ReleaseNotes.rst
docs/clang-tidy/checks/fuchsia-multiple-inheritance.rst
docs/clang-tidy/checks/list.rst
test/clang-tidy/fuchsia-multiple-inheritance.cpp
Index: test/clang-tidy/fuchsia-multiple-inheritance.cpp
===================================================================
--- /dev/null
+++ test/clang-tidy/fuchsia-multiple-inheritance.cpp
@@ -0,0 +1,91 @@
+// RUN: %check_clang_tidy %s fuchsia-multiple-inheritance %t
+
+class Base_A {
+public:
+ virtual int foo() { return 0; }
+};
+
+class Base_B {
+public:
+ virtual int bar() { return 0; }
+};
+
+class Base_A_child : public Base_A {
+public:
+ virtual int baz() { return 0; }
+};
+
+class Interface_A {
+public:
+ virtual int foo() = 0;
+};
+
+class Interface_B {
+public:
+ virtual int bar() = 0;
+};
+
+class Interface_C {
+public:
+ virtual int blat() = 0;
+};
+
+class Interface_A_with_member {
+public:
+ virtual int foo() = 0;
+ int val = 0;
+};
+
+class Interface_with_A_Parent : public Base_A {
+public:
+ virtual int baz() = 0;
+};
+
+// Inherits from multiple concrete classes.
+// CHECK-MESSAGES: [[@LINE+2]]:1: warning: inheriting mulitple classes which aren't pure virtual is disallowed [fuchsia-multiple-inheritance]
+// CHECK-NEXT: class Bad_Child1 : public Base_A, Base_B {};
+class Bad_Child1 : public Base_A, Base_B {};
+
+// CHECK-MESSAGES: [[@LINE+1]]:1: warning: inheriting mulitple classes which aren't pure virtual is disallowed [fuchsia-multiple-inheritance]
+class Bad_Child2 : public Base_A, Interface_A_with_member {
+ virtual int foo() override { return 0; }
+};
+
+// CHECK-MESSAGES: [[@LINE+2]]:1: warning: inheriting mulitple classes which aren't pure virtual is disallowed [fuchsia-multiple-inheritance]
+// CHECK-NEXT: class Bad_Child3 : public Interface_with_A_Parent, Base_B {
+class Bad_Child3 : public Interface_with_A_Parent, Base_B {
+ virtual int baz() override { return 0; }
+};
+
+// Easy cases of single inheritance
+class Simple_Child1 : public Base_A {};
+class Simple_Child2 : public Interface_A {
+ virtual int foo() override { return 0; }
+};
+
+// Valid uses of multiple inheritance
+class Good_Child1 : public Interface_A, Interface_B {
+ virtual int foo() override { return 0; }
+ virtual int bar() override { return 0; }
+};
+
+class Good_Child2 : public Base_A, Interface_B {
+ virtual int bar() override { return 0; }
+};
+
+class Good_Child3 : public Base_A_child, Interface_C, Interface_B {
+ virtual int bar() override { return 0; }
+ virtual int blat() override { return 0; }
+};
+
+int main(void) {
+ Bad_Child1 a;
+ Bad_Child2 b;
+ Bad_Child3 c;
+ Simple_Child1 d;
+ Simple_Child2 e;
+ Good_Child1 f;
+ Good_Child2 g;
+ Good_Child3 h;
+ return 0;
+}
Index: docs/clang-tidy/checks/list.rst
===================================================================
--- docs/clang-tidy/checks/list.rst
+++ docs/clang-tidy/checks/list.rst
@@ -69,6 +69,7 @@
cppcoreguidelines-slicing
cppcoreguidelines-special-member-functions
fuchsia-default-arguments
+ fuchsia-multiple-inheritance
google-build-explicit-make-pair
google-build-namespaces
google-build-using-namespace
Index: docs/clang-tidy/checks/fuchsia-multiple-inheritance.rst
===================================================================
--- /dev/null
+++ docs/clang-tidy/checks/fuchsia-multiple-inheritance.rst
@@ -0,0 +1,46 @@
+.. title:: clang-tidy - fuchsia-multiple-inheritance
+
+fuchsia-multiple-inheritance
+============================
+
+Warns if a class inherits from multiple classes that are not pure virtual.
+
+For example, declaring a class that inherits from multiple concrete classes is
+disallowed:
+
+.. code-block:: c++
+
+ class Base_A {
+ public:
+ virtual int foo() { return 0; }
+ };
+
+ class Base_B {
+ public:
+ virtual int bar() { return 0; }
+ };
+
+ // Warning
+ class Bad_Child1 : public Base_A, Base_B {};
+
+A class that inherits from a pure virtual is allowed:
+
+.. code-block:: c++
+
+ class Interface_A {
+ public:
+ virtual int foo() = 0;
+ };
+
+ class Interface_B {
+ public:
+ virtual int bar() = 0;
+ };
+
+ // No warning
+ class Good_Child1 : public Interface_A, Interface_B {
+ virtual int foo() override { return 0; }
+ virtual int bar() override { return 0; }
+ };
+
+See the features disallowed in Fuchsia at https://fuchsia.googlesource.com/zircon/+/master/docs/cxx.md
Index: docs/ReleaseNotes.rst
===================================================================
--- docs/ReleaseNotes.rst
+++ docs/ReleaseNotes.rst
@@ -114,6 +114,11 @@
<http://clang.llvm.org/extra/clang-tidy/checks/fuchsia-default-arguments.html>`_ check
Warns if a function or method is declared or called with default arguments.
+
+- New `fuchsia-multiple-inheritance
+ <http://clang.llvm.org/extra/clang-tidy/checks/fuchsia-default-arguments.html>`_ check
+
+ Warns if a class inherits from multiple classes that are not pure virtual.
- New `google-avoid-throwing-objc-exception
<http://clang.llvm.org/extra/clang-tidy/checks/google-objc-avoid-throwing-exception.html>`_ check
Index: clang-tidy/fuchsia/MultipleInheritanceCheck.h
===================================================================
--- /dev/null
+++ clang-tidy/fuchsia/MultipleInheritanceCheck.h
@@ -0,0 +1,51 @@
+//===--- MultipleInheritanceCheck.h - clang-tidy-----------------*- C++ -*-===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_FUCHSIA_MULTIPLE_INHERITANCE_H
+#define LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_FUCHSIA_MULTIPLE_INHERITANCE_H
+
+#include "../ClangTidy.h"
+
+namespace clang {
+namespace tidy {
+namespace fuchsia {
+
+/// Mulitple inheritance is disallowed.
+///
+/// For the user-facing documentation see:
+/// http://clang.llvm.org/extra/clang-tidy/checks/fuchsia-multiple-inheritance.html
+class MultipleInheritanceCheck : public ClangTidyCheck {
+public:
+ MultipleInheritanceCheck(StringRef Name, ClangTidyContext *Context)
+ : ClangTidyCheck(Name, Context) {}
+ void registerMatchers(ast_matchers::MatchFinder *Finder) override;
+ void check(const ast_matchers::MatchFinder::MatchResult &Result) override;
+
+ void onStartOfTranslationUnit() override {
+ InterfaceMap = new llvm::StringMap<bool>;
+ }
+ void onEndOfTranslationUnit() override { delete InterfaceMap; }
+
+ void addNodeToInterfaceMap(const CXXRecordDecl *Node, bool isInterface);
+ bool getInterfaceStatus(const CXXRecordDecl *Node, bool *isInterface);
+ bool isCurrentClassInterface(const CXXRecordDecl *Node);
+ bool isInterface(const CXXRecordDecl *Node);
+
+private:
+ // Contains the identity of each named CXXRecord as an interface. This is
+ // used to memoize lookup speeds and improve performance from O(N^2) to O(N),
+ // where N is the number of classes.
+ llvm::StringMap<bool> *InterfaceMap;
+};
+
+} // namespace fuchsia
+} // namespace tidy
+} // namespace clang
+
+#endif // LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_FUCHSIA_MULTIPLE_INHERITANCE_H
Index: clang-tidy/fuchsia/MultipleInheritanceCheck.cpp
===================================================================
--- /dev/null
+++ clang-tidy/fuchsia/MultipleInheritanceCheck.cpp
@@ -0,0 +1,120 @@
+//===--- MultipleInheritanceCheck.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 "MultipleInheritanceCheck.h"
+#include "clang/AST/ASTContext.h"
+#include "clang/ASTMatchers/ASTMatchFinder.h"
+
+using namespace clang;
+using namespace clang::ast_matchers;
+
+namespace clang {
+namespace tidy {
+namespace fuchsia {
+
+AST_MATCHER(CXXRecordDecl, hasDefinition) {
+ if (!Node.hasDefinition())
+ return false;
+ return true;
+}
+
+// Adds a node (by name) to the interface map, if it was not present in the map
+// previously.
+void MultipleInheritanceCheck::addNodeToInterfaceMap(const CXXRecordDecl *Node,
+ bool isInterface) {
+ StringRef Name = Node->getIdentifier()->getName();
+ MultipleInheritanceCheck::InterfaceMap->insert(
+ std::make_pair(Name, isInterface));
+}
+
+// Returns "true" if the boolean "isInterface" has been set to the
+// interface status of the current Node. Return "false" if the
+// interface status for the current node is not yet known.
+bool MultipleInheritanceCheck::getInterfaceStatus(const CXXRecordDecl *Node,
+ bool *isInterface) {
+ StringRef Name = Node->getIdentifier()->getName();
+ if (MultipleInheritanceCheck::InterfaceMap->count(Name)) {
+ *isInterface = MultipleInheritanceCheck::InterfaceMap->lookup(Name);
+ return true;
+ }
+ return false;
+}
+
+// TODO(smklein): Make an exception for 'Dispatcher' -- consider it an
+// interface, even though it isn't.
+bool MultipleInheritanceCheck::isCurrentClassInterface(
+ const CXXRecordDecl *Node) {
+ // Interfaces should have no fields.
+ if (!Node->field_empty()) {
+ return false;
+ }
+ // Interfaces should have exclusively pure methods.
+ for (const auto method : Node->methods()) {
+ if (method->isUserProvided() && !method->isPure()) {
+ return false;
+ }
+ }
+ return true;
+}
+
+bool MultipleInheritanceCheck::isInterface(const CXXRecordDecl *Node) {
+ // Short circuit the lookup if we have analyzed this record before.
+ bool PreviousIsInterfaceResult;
+ if (MultipleInheritanceCheck::getInterfaceStatus(Node,
+ &PreviousIsInterfaceResult)) {
+ return PreviousIsInterfaceResult;
+ }
+
+ // To be an interface, all base classes must be interfaces as well.
+ for (const auto &I : Node->bases()) {
+ const RecordType *Ty = I.getType()->getAs<RecordType>();
+ assert(Ty && "RecordType of base class is unknown");
+ const auto *Base = cast<CXXRecordDecl>(Ty->getDecl()->getDefinition());
+ if (!MultipleInheritanceCheck::isInterface(Base)) {
+ MultipleInheritanceCheck::addNodeToInterfaceMap(Node, false);
+ return false;
+ }
+ }
+
+ bool CurrentClassIsInterface =
+ MultipleInheritanceCheck::isCurrentClassInterface(Node);
+ MultipleInheritanceCheck::addNodeToInterfaceMap(Node,
+ CurrentClassIsInterface);
+ return CurrentClassIsInterface;
+}
+
+void MultipleInheritanceCheck::registerMatchers(MatchFinder *Finder) {
+ // Match declarations which have definitions.
+ Finder->addMatcher(cxxRecordDecl(hasDefinition()).bind("decl"), this);
+}
+
+void MultipleInheritanceCheck::check(const MatchFinder::MatchResult &Result) {
+ if (const CXXRecordDecl *D =
+ Result.Nodes.getNodeAs<CXXRecordDecl>("decl")) {
+ // Check against map to see if if the class inherits from multiple
+ // concrete classes
+ int NumConcrete = 0;
+ for (const auto &I : D->bases()) {
+ const RecordType *Ty = I.getType()->getAs<RecordType>();
+ assert(Ty && "RecordType of base class is unknown");
+ CXXRecordDecl *Base = cast<CXXRecordDecl>(Ty->getDecl()->getDefinition());
+ if (!MultipleInheritanceCheck::isInterface(Base))
+ NumConcrete++;
+ }
+
+ if (NumConcrete > 1) {
+ diag(D->getLocStart(), "inheriting mulitple classes which aren't "
+ "pure virtual is disallowed");
+ }
+ }
+}
+
+} // namespace fuchsia
+} // namespace tidy
+} // namespace clang
Index: clang-tidy/fuchsia/FuchsiaTidyModule.cpp
===================================================================
--- clang-tidy/fuchsia/FuchsiaTidyModule.cpp
+++ clang-tidy/fuchsia/FuchsiaTidyModule.cpp
@@ -11,6 +11,7 @@
#include "../ClangTidyModule.h"
#include "../ClangTidyModuleRegistry.h"
#include "DefaultArgumentsCheck.h"
+#include "MultipleInheritanceCheck.h"
using namespace clang::ast_matchers;
@@ -24,6 +25,8 @@
void addCheckFactories(ClangTidyCheckFactories &CheckFactories) override {
CheckFactories.registerCheck<DefaultArgumentsCheck>(
"fuchsia-default-arguments");
+ CheckFactories.registerCheck<MultipleInheritanceCheck>(
+ "fuchsia-multiple-inheritance");
}
};
// Register the FuchsiaTidyModule using this statically initialized variable.
Index: clang-tidy/fuchsia/CMakeLists.txt
===================================================================
--- clang-tidy/fuchsia/CMakeLists.txt
+++ clang-tidy/fuchsia/CMakeLists.txt
@@ -3,6 +3,7 @@
add_clang_library(clangTidyFuchsiaModule
DefaultArgumentsCheck.cpp
FuchsiaTidyModule.cpp
+ MultipleInheritanceCheck.cpp
LINK_LIBS
clangAST
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