https://github.com/dongjianqiang2 created
https://github.com/llvm/llvm-project/pull/73077
Adds a warning, issued by the clang semantic analysis. The patch warns on
switch which don't have the default branch.
This is a counterpart of gcc's Wswitch-default.
>From 7962e1ffc6bb5ab8873f391f5030199ba62c1345 Mon Sep 17 00:00:00 2001
From: dong jianqiang <dongjianqia...@huawei.com>
Date: Wed, 22 Nov 2023 11:06:00 +0800
Subject: [PATCH] [clang][Sema] Add -Wswitch-default warning option
Adds a warning, issued by the clang semantic analysis. The patch warns on switch
which don't have the default branch.
This is a counterpart of gcc's Wswitch-default.
---
clang/include/clang/Basic/DiagnosticGroups.td | 2 +-
.../include/clang/Basic/DiagnosticSemaKinds.td | 2 ++
clang/lib/Sema/SemaStmt.cpp | 3 +++
clang/test/Sema/switch-default.c | 17 +++++++++++++++++
4 files changed, 23 insertions(+), 1 deletion(-)
create mode 100644 clang/test/Sema/switch-default.c
diff --git a/clang/include/clang/Basic/DiagnosticGroups.td
b/clang/include/clang/Basic/DiagnosticGroups.td
index ff028bbbf74261e..12b11527b30571a 100644
--- a/clang/include/clang/Basic/DiagnosticGroups.td
+++ b/clang/include/clang/Basic/DiagnosticGroups.td
@@ -632,7 +632,7 @@ def ShadowAll : DiagGroup<"shadow-all", [Shadow,
ShadowFieldInConstructor,
def Shorten64To32 : DiagGroup<"shorten-64-to-32">;
def : DiagGroup<"sign-promo">;
def SignCompare : DiagGroup<"sign-compare">;
-def : DiagGroup<"switch-default">;
+def SwitchDefault : DiagGroup<"switch-default">;
def : DiagGroup<"synth">;
def SizeofArrayArgument : DiagGroup<"sizeof-array-argument">;
def SizeofArrayDecay : DiagGroup<"sizeof-array-decay">;
diff --git a/clang/include/clang/Basic/DiagnosticSemaKinds.td
b/clang/include/clang/Basic/DiagnosticSemaKinds.td
index 990692c06d7d3a8..17c9627910bb6ce 100644
--- a/clang/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/clang/include/clang/Basic/DiagnosticSemaKinds.td
@@ -10044,6 +10044,8 @@ def warn_missing_case : Warning<"%plural{"
"3:enumeration values %1, %2, and %3 not handled in switch|"
":%0 enumeration values not handled in switch: %1, %2, %3...}0">,
InGroup<Switch>;
+def warn_switch_default : Warning<"switch missing default case">,
+ InGroup<SwitchDefault>, DefaultIgnore;
def warn_unannotated_fallthrough : Warning<
"unannotated fall-through between switch labels">,
diff --git a/clang/lib/Sema/SemaStmt.cpp b/clang/lib/Sema/SemaStmt.cpp
index 2b45aa5dff7be7c..63348d27a8c94a1 100644
--- a/clang/lib/Sema/SemaStmt.cpp
+++ b/clang/lib/Sema/SemaStmt.cpp
@@ -1327,6 +1327,9 @@ Sema::ActOnFinishSwitchStmt(SourceLocation SwitchLoc,
Stmt *Switch,
}
}
+ if (!TheDefaultStmt)
+ Diag(SwitchLoc, diag::warn_switch_default);
+
if (!HasDependentValue) {
// If we don't have a default statement, check whether the
// condition is constant.
diff --git a/clang/test/Sema/switch-default.c b/clang/test/Sema/switch-default.c
new file mode 100644
index 000000000000000..3f2e21693303378
--- /dev/null
+++ b/clang/test/Sema/switch-default.c
@@ -0,0 +1,17 @@
+// RUN: %clang_cc1 -fsyntax-only -verify -Wswitch-default %s
+
+int f1(int a) {
+ switch (a) { // expected-warning {{switch missing default
case}}
+ case 1: a++; break;
+ case 2: a += 2; break;
+ }
+ return a;
+}
+
+int f2(int a) {
+ switch (a) { // no-warning
+ default:
+ ;
+ }
+ return a;
+}
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