xgupta updated this revision to Diff 540845.
xgupta marked an inline comment as done.
xgupta added a comment.
Updated testcase [WIP]
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D4784/new/
https://reviews.llvm.org/D4784
Files:
clang-tools-extra/clang-tidy/bugprone/BugproneTidyModule.cpp
clang-tools-extra/clang-tidy/bugprone/CMakeLists.txt
clang-tools-extra/clang-tidy/bugprone/SwitchMissingDefaultCaseCheck.cpp
clang-tools-extra/clang-tidy/bugprone/SwitchMissingDefaultCaseCheck.h
clang-tools-extra/docs/ReleaseNotes.rst
clang-tools-extra/docs/clang-tidy/checks/bugprone/switch-missing-default-case.rst
clang-tools-extra/docs/clang-tidy/checks/list.rst
clang-tools-extra/test/clang-tidy/checkers/bugprone/switch-missing-default-case.cpp
Index: clang-tools-extra/test/clang-tidy/checkers/bugprone/switch-missing-default-case.cpp
===================================================================
--- /dev/null
+++ clang-tools-extra/test/clang-tidy/checkers/bugprone/switch-missing-default-case.cpp
@@ -0,0 +1,80 @@
+// RUN: %check_clang_tidy %s bugprone-switch-missing-default-case %t -- -- -fno-delayed-template-parsing
+
+typedef int MyInt;
+enum EnumType { eE2 };
+typedef EnumType MyEnum;
+
+void positive() {
+ int I1 = 0;
+ // CHECK-MESSAGES: [[@LINE+1]]:11: warning: switching on non-enum value without default case may not cover all cases [bugprone-switch-missing-default-case]
+ switch (I1) {
+ case 0:
+ break;
+ }
+
+ MyInt I2 = 0;
+ // CHECK-MESSAGES: [[@LINE+1]]:11: warning: switching on non-enum value without default case may not cover all cases [bugprone-switch-missing-default-case]
+ switch (I2) {
+ case 0:
+ break;
+ }
+
+ int getValue(void);
+ // CHECK-MESSAGES: [[@LINE+1]]:11: warning: switching on non-enum value without default case may not cover all cases [bugprone-switch-missing-default-case]
+ switch (getValue()) {
+ case 0:
+ break;
+ }
+}
+
+void negative() {
+ enum E { eE1 };
+ E E1 = eE1;
+ switch (E1) { // no-warning
+ case eE1:
+ break;
+ }
+
+ MyEnum E2 = eE2;
+ switch (E2) { // no-warning
+ case eE2:
+ break;
+ }
+
+ int I1 = 0;
+ switch (I1) { // no-warning
+ case 0:
+ break;
+ default:
+ break;
+ }
+
+ MyInt I2 = 0;
+ switch (I2) { // no-warning
+ case 0:
+ break;
+ default:
+ break;
+ }
+
+ int getValue(void);
+ switch (getValue()) { // no-warning
+ case 0:
+ break;
+ default:
+ break;
+ }
+}
+
+template<typename T>
+void testTemplate(T Value) {
+ switch (Value) {
+ case 0:
+ break;
+ }
+}
+
+void exampleUsage() {
+ testTemplate(5);
+ testTemplate(EnumType::eE2);
+}
Index: clang-tools-extra/docs/clang-tidy/checks/list.rst
===================================================================
--- clang-tools-extra/docs/clang-tidy/checks/list.rst
+++ clang-tools-extra/docs/clang-tidy/checks/list.rst
@@ -92,6 +92,7 @@
`bugprone-forwarding-reference-overload <bugprone/forwarding-reference-overload.html>`_,
`bugprone-implicit-widening-of-multiplication-result <bugprone/implicit-widening-of-multiplication-result.html>`_, "Yes"
`bugprone-inaccurate-erase <bugprone/inaccurate-erase.html>`_, "Yes"
+ `bugprone-switch-missing-default-case <bugprone/switch-missing-default-case.html>`_,
`bugprone-incorrect-roundings <bugprone/incorrect-roundings.html>`_,
`bugprone-infinite-loop <bugprone/infinite-loop.html>`_,
`bugprone-integer-division <bugprone/integer-division.html>`_,
Index: clang-tools-extra/docs/clang-tidy/checks/bugprone/switch-missing-default-case.rst
===================================================================
--- /dev/null
+++ clang-tools-extra/docs/clang-tidy/checks/bugprone/switch-missing-default-case.rst
@@ -0,0 +1,56 @@
+.. title:: clang-tidy - bugprone-switch-missing-default-case
+
+bugprone-switch-missing-default-case
+====================================
+
+Ensures that switch statements without default cases are flagged, focuses only
+on covering cases with non-enums where the compiler may not issue warnings.
+
+Switch statements without a default case can lead to unexpected
+behavior and incomplete handling of all possible cases. When a switch statement
+lacks a default case, if a value is encountered that does not match any of the
+specified cases, the program will continue execution without any defined
+behavior or handling.
+
+This check helps identify switch statements that are missing a default case,
+allowing developers to ensure that all possible cases are handled properly.
+Adding a default case allows for graceful handling of unexpected or unmatched
+values, reducing the risk of program errors and unexpected behavior.
+
+Example:
+
+.. code-block:: c++
+
+ // Example 1:
+ // warning: switching on non-enum value without default case may not cover all cases
+ switch (i) {
+ case 0:
+ break;
+ }
+
+ // Example 2:
+ enum E { eE1 };
+ E e = eE1;
+ switch (e) { // no-warning
+ case eE1:
+ break;
+ }
+
+ // Example 3:
+ int i = 0;
+ switch (i) { // no-warning
+ case 0:
+ break;
+ default:
+ break;
+ }
+
+.. note::
+ Enum types are already covered by compiler warnings (comes under -Wswitch)
+ when a switch statement does not handle all enum values. This check focuses
+ on non-enum types where the compiler warnings may not be present.
+
+.. seealso::
+ The `CppCoreGuideline ES.79 <https://isocpp.github.io/CppCoreGuidelines/CppCoreGuidelines#Res-default>`_
+ provide guidelines on switch statements, including the recommendation to
+ always provide a default case.
Index: clang-tools-extra/docs/ReleaseNotes.rst
===================================================================
--- clang-tools-extra/docs/ReleaseNotes.rst
+++ clang-tools-extra/docs/ReleaseNotes.rst
@@ -121,6 +121,12 @@
Detect implicit and explicit casts of ``enum`` type into ``bool`` where ``enum`` type
doesn't have a zero-value enumerator.
+- New :doc:`bugprone-switch-missing-default-case
+ <clang-tidy/checks/bugprone/switch-missing-default-case>` check.
+
+ Ensures that switch statements without default cases are flagged, focuses only
+ on covering cases with non-enums where the compiler may not issue warnings.
+
- New :doc:`bugprone-unique-ptr-array-mismatch
<clang-tidy/checks/bugprone/unique-ptr-array-mismatch>` check.
Index: clang-tools-extra/clang-tidy/bugprone/SwitchMissingDefaultCaseCheck.h
===================================================================
--- /dev/null
+++ clang-tools-extra/clang-tidy/bugprone/SwitchMissingDefaultCaseCheck.h
@@ -0,0 +1,32 @@
+//===--- SwitchMissingDefaultCaseCheck.h - clang-tidy -----------*- C++ -*-===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_BUGPRONE_SWITCHMISSINGDEFAULTCASECHECK_H
+#define LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_BUGPRONE_SWITCHMISSINGDEFAULTCASECHECK_H
+
+#include "../ClangTidyCheck.h"
+#include "clang/ASTMatchers/ASTMatchFinder.h"
+#include "clang/ASTMatchers/ASTMatchers.h"
+
+namespace clang::tidy::bugprone {
+
+class SwitchMissingDefaultCaseCheck : public ClangTidyCheck {
+public:
+ SwitchMissingDefaultCaseCheck(StringRef Name, ClangTidyContext *Context)
+ : ClangTidyCheck(Name, Context) {}
+
+ void registerMatchers(ast_matchers::MatchFinder *Finder) override;
+ void check(const ast_matchers::MatchFinder::MatchResult &Result) override;
+ std::optional<TraversalKind> getCheckTraversalKind() const override {
+ return TK_IgnoreUnlessSpelledInSource;
+ }
+};
+
+} // namespace clang::tidy::bugprone
+
+#endif // LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_BUGPRONE_SWITCHMISSINGDEFAULTCASECHECK_H
Index: clang-tools-extra/clang-tidy/bugprone/SwitchMissingDefaultCaseCheck.cpp
===================================================================
--- /dev/null
+++ clang-tools-extra/clang-tidy/bugprone/SwitchMissingDefaultCaseCheck.cpp
@@ -0,0 +1,46 @@
+//===--- SwitchMissingDefaultCaseCheck.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 "SwitchMissingDefaultCaseCheck.h"
+#include "clang/AST/ASTContext.h"
+
+using namespace clang::ast_matchers;
+
+namespace clang::tidy::bugprone {
+
+AST_MATCHER(SwitchStmt, hasDefaultCase) {
+ const SwitchCase *Case = Node.getSwitchCaseList();
+ while (Case) {
+ if (DefaultStmt::classof(Case))
+ return true;
+
+ Case = Case->getNextSwitchCase();
+ }
+ return false;
+}
+
+void SwitchMissingDefaultCaseCheck::registerMatchers(MatchFinder *Finder) {
+ Finder->addMatcher(
+ switchStmt(hasCondition(expr(unless(isInstantiationDependent()),
+ hasType(qualType(hasCanonicalType(
+ unless(hasDeclaration(enumDecl()))))))),
+ unless(hasDefaultCase()))
+ .bind("switch"),
+ this);
+}
+
+void SwitchMissingDefaultCaseCheck::check(
+ const ast_matchers::MatchFinder::MatchResult &Result) {
+ const auto *Switch = Result.Nodes.getNodeAs<SwitchStmt>("switch");
+ if (!Switch)
+ return;
+
+ diag(Switch->getSwitchLoc(), "switching on non-enum value without "
+ "default case may not cover all cases");
+}
+} // namespace clang::tidy::bugprone
Index: clang-tools-extra/clang-tidy/bugprone/CMakeLists.txt
===================================================================
--- clang-tools-extra/clang-tidy/bugprone/CMakeLists.txt
+++ clang-tools-extra/clang-tidy/bugprone/CMakeLists.txt
@@ -21,6 +21,7 @@
ForwardingReferenceOverloadCheck.cpp
ImplicitWideningOfMultiplicationResultCheck.cpp
InaccurateEraseCheck.cpp
+ SwitchMissingDefaultCaseCheck.cpp
IncorrectRoundingsCheck.cpp
InfiniteLoopCheck.cpp
IntegerDivisionCheck.cpp
Index: clang-tools-extra/clang-tidy/bugprone/BugproneTidyModule.cpp
===================================================================
--- clang-tools-extra/clang-tidy/bugprone/BugproneTidyModule.cpp
+++ clang-tools-extra/clang-tidy/bugprone/BugproneTidyModule.cpp
@@ -65,6 +65,7 @@
#include "SuspiciousSemicolonCheck.h"
#include "SuspiciousStringCompareCheck.h"
#include "SwappedArgumentsCheck.h"
+#include "SwitchMissingDefaultCaseCheck.h"
#include "TerminatingContinueCheck.h"
#include "ThrowKeywordMissingCheck.h"
#include "TooSmallLoopVariableCheck.h"
@@ -116,6 +117,8 @@
"bugprone-implicit-widening-of-multiplication-result");
CheckFactories.registerCheck<InaccurateEraseCheck>(
"bugprone-inaccurate-erase");
+ CheckFactories.registerCheck<SwitchMissingDefaultCaseCheck>(
+ "bugprone-switch-missing-default-case");
CheckFactories.registerCheck<IncorrectRoundingsCheck>(
"bugprone-incorrect-roundings");
CheckFactories.registerCheck<InfiniteLoopCheck>("bugprone-infinite-loop");
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