`PP->getMacroInfo()` returns nullptr for undefined macro, which leads to null-dereference at `MI->tockens().back()`.
Stack dump:
```
#0 0x000000000217d15a llvm::sys::PrintStackTrace(llvm::raw_ostream&) (/llvm-project/build/bin/clang-tidy+0x217d15a)
#1 0x000000000217b17c llvm::sys::RunSignalHandlers() (/llvm-project/build/bin/clang-tidy+0x217b17c)
#2 0x000000000217b2e3 SignalHandler(int) (/llvm-project/build/bin/clang-tidy+0x217b2e3)
#3 0x00007f39be5b1390 __restore_rt (/lib/x86_64-linux-gnu/libpthread.so.0+0x11390)
#4 0x0000000000593532 clang::tidy::bugprone::BadSignalToKillThreadCheck::check(clang::ast_matchers::MatchFinder::MatchResult const&) (/llvm-project/build/bin/clang-tidy+0x593532)
```
Reviewed By: hokein
Differential Revision: https://reviews.llvm.org/D85401
void BadSignalToKillThreadCheck::check(const MatchFinder::MatchResult &Result) {
const auto IsSigterm = [](const auto &KeyValue) -> bool {
- return KeyValue.first->getName() == "SIGTERM";
+ return KeyValue.first->getName() == "SIGTERM" &&
+ KeyValue.first->hasMacroDefinition();
};
const auto TryExpandAsInteger =
[](Preprocessor::macro_iterator It) -> Optional<unsigned> {
--- /dev/null
+// RUN: clang-tidy %s --checks=-*,bugprone-bad-signal-to-kill-thread -- | count 0
+
+#define SIGTERM 15
+#undef SIGTERM // no-crash
+using pthread_t = int;
+int pthread_kill(pthread_t thread, int sig);
+
+int func() {
+ pthread_t thread;
+ return pthread_kill(thread, 0);
+}