[ADT] Add DefaultUnreachable("msg") to StringSwitch
#161976
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Similar to TypeSwitch (llvm#161970), allow for explicit unreachable default case with a custom error message on unhandled cases. StringSwitch already allowed for checking if any of the cases matched with the conversion operator, but `DefaultUnreachable` is more explicit and allows for a custom message.
kuhar
requested review from
nikic,
zero9178,
hanhanW,
Groverkss and
kazutakahirata
|
@llvm/pr-subscribers-llvm-adt Author: Jakub Kuderski (kuhar) ChangesSimilar to TypeSwitch (#161970), allow for explicit unreachable default case with a custom error message on unhandled cases. StringSwitch already allowed for checking if any of the cases matched with the conversion operator, but Full diff: https://github.com/llvm/llvm-project/pull/161976.diff 2 Files Affected:
diff --git a/llvm/include/llvm/ADT/StringSwitch.h b/llvm/include/llvm/ADT/StringSwitch.h
index 86e591c71c92e..18eadcd10fb9b 100644
--- a/llvm/include/llvm/ADT/StringSwitch.h
+++ b/llvm/include/llvm/ADT/StringSwitch.h
@@ -14,6 +14,7 @@
#define LLVM_ADT_STRINGSWITCH_H
#include "llvm/ADT/StringRef.h"
+#include "llvm/Support/ErrorHandling.h"
#include <cassert>
#include <cstring>
#include <optional>
@@ -180,11 +181,15 @@ class StringSwitch {
return Value;
}
- [[nodiscard]] operator R() {
- assert(Result && "Fell off the end of a string-switch");
- return std::move(*Result);
+ [[nodiscard]] R DefaultUnreachable(
+ const char *Message = "Fell off the end of a string-switch") {
+ if (Result)
+ return std::move(*Result);
+ llvm_unreachable(Message);
}
+ [[nodiscard]] operator R() { return DefaultUnreachable(); }
+
private:
// Returns true when `Str` matches the `S` argument, and stores the result.
bool CaseImpl(T &Value, StringLiteral S) {
diff --git a/llvm/unittests/ADT/StringSwitchTest.cpp b/llvm/unittests/ADT/StringSwitchTest.cpp
index 2953f4b0a381b..bcb1521baa287 100644
--- a/llvm/unittests/ADT/StringSwitchTest.cpp
+++ b/llvm/unittests/ADT/StringSwitchTest.cpp
@@ -230,3 +230,19 @@ TEST(StringSwitchTest, CasesCopies) {
"Foo", "Bar", "Baz", "Qux", Copyable{NumCopies});
EXPECT_EQ(NumCopies, 1u);
}
+
+TEST(StringSwitchTest, DefaultUnreachable) {
+ auto Translate = [](StringRef S) {
+ return llvm::StringSwitch<int>(S)
+ .Case("A", 0)
+ .Case("B", 1)
+ .DefaultUnreachable("Unhandled case");
+ };
+
+ EXPECT_EQ(0, Translate("A"));
+ EXPECT_EQ(1, Translate("B"));
+
+#if defined(GTEST_HAS_DEATH_TEST) && !defined(NDEBUG)
+ EXPECT_DEATH((void)Translate("C"), "Unhandled case");
+#endif
+}
|
zero9178
approved these changes
Oct 4, 2025
nikic
approved these changes
Oct 5, 2025
|
LLVM Buildbot has detected a new failure on builder Full details are available at: https://lab.llvm.org/buildbot/#/builders/128/builds/7527 Here is the relevant piece of the build log for the reference |
|
LLVM Buildbot has detected a new failure on builder Full details are available at: https://lab.llvm.org/buildbot/#/builders/27/builds/17051 Here is the relevant piece of the build log for the reference |
|
LLVM Buildbot has detected a new failure on builder Full details are available at: https://lab.llvm.org/buildbot/#/builders/169/builds/15654 Here is the relevant piece of the build log for the reference |
aokblast
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Oct 6, 2025
Similar to TypeSwitch (llvm#161970), allow for explicit unreachable default case with a custom error message on unhandled cases. StringSwitch already allowed for checking if any of the cases matched with the conversion operator, but `DefaultUnreachable` is more explicit and allows for a custom message.
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Similar to TypeSwitch (#161970), allow for explicit unreachable default case with a custom error message on unhandled cases.
StringSwitch already allowed for checking if any of the cases matched with the conversion operator, but
DefaultUnreachableis more explicit and allows for a custom message.