xgupta updated this revision to Diff 539602.
xgupta added a comment.
Add documentation
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 +1,27 @@
+// RUN: %check_clang_tidy %s bugprone-switch-missing-default-case -- %t
+
+void Positive() {
+ int i = 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 (i) {
+ case 0:
+ break;
+ }
+}
+
+void Negative() {
+ enum E { eE1 };
+ E e = eE1;
+ switch (e) { // no-warning
+ case eE1:
+ break;
+ }
+
+ int i = 0;
+ switch (i) { // no-warning
+ case 0:
+ break;
+ default:
+ break;
+ }
+}
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>`_, "Yes"
`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 +1,58 @@
+.. title:: clang-tidy - bugprone-switch-missing-default-case
+
+bugprone-switch-missing-default-case
+===================================
+
+Detects incomplete switch statements without a default case.
+
+For exmaple:
+
+.. code-block:: c++
+
+ // Example 1:
+ switch (i) { // warning: switching on non-enum value without default case may not cover all cases [bugprone-switch-missing-default-case]
+ 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;
+ }
+
+Incomplete 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.
+
+Options
+-------
+
+This check does not have any configurable options.
+
+.. note::
+ Enum types are already covered by compiler warnings 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 C++ Core Guidelines provide guidelines on switch statements, including
+ the recommendation to always provide a default case: :cpp:dir:`C.89`.
Index: clang-tools-extra/docs/ReleaseNotes.rst
===================================================================
--- clang-tools-extra/docs/ReleaseNotes.rst
+++ clang-tools-extra/docs/ReleaseNotes.rst
@@ -219,6 +219,12 @@
Enforces consistent token representation for invoked binary, unary and
overloaded operators in C++ code.
+- New :doc:`bugprone-switch-missing-default-case
+ <clang-tidy/checks/bugprone/switch-missing-default-case>` check.
+
+ Ensures that incomplete switch statements without default cases are
+ flagged, covering cases beyond enums where the compiler may not issue warnings.
+
New check aliases
^^^^^^^^^^^^^^^^^
Index: clang-tools-extra/clang-tidy/bugprone/SwitchMissingDefaultCaseCheck.h
===================================================================
--- /dev/null
+++ clang-tools-extra/clang-tidy/bugprone/SwitchMissingDefaultCaseCheck.h
@@ -0,0 +1,29 @@
+//===--- 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;
+};
+
+} // 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 +1,36 @@
+//===--- 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 {
+
+void SwitchMissingDefaultCaseCheck::registerMatchers(
+ ast_matchers::MatchFinder *Finder) {
+ Finder->addMatcher(
+ switchStmt(has(implicitCastExpr().bind("cast")),
+ unless(hasAncestor(switchStmt(has(defaultStmt())))))
+ .bind("switch"),
+ this);
+}
+
+void SwitchMissingDefaultCaseCheck::check(
+ const ast_matchers::MatchFinder::MatchResult &Result) {
+ const auto *CastExpr = Result.Nodes.getNodeAs<ImplicitCastExpr>("cast");
+ if (CastExpr->getCastKind() == CK_IntegralCast)
+ return;
+
+ const auto *Switch = Result.Nodes.getNodeAs<SwitchStmt>("switch");
+ 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
@@ -26,6 +26,7 @@
#include "ForwardingReferenceOverloadCheck.h"
#include "ImplicitWideningOfMultiplicationResultCheck.h"
#include "InaccurateEraseCheck.h"
+#include "SwitchMissingDefaultCaseCheck.h"
#include "IncorrectRoundingsCheck.h"
#include "InfiniteLoopCheck.h"
#include "IntegerDivisionCheck.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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