[analyzer] Prevent assertion failure in PThreadLockChecker when the implementations of the locking functions are available

[xazax.hun]

Summary

This is very unlikely to happen for PThreads, but using the CSA on a libc or Fuchsia will trigger this assertion failure.

[NoQ]

That's a safe default behavior, but ideally you should see if the annotation on the function can be applied after inlining. Like, it isn't necessarily always applicable, but when it is, you might be able to improve coverage.

[xazax.hun]

In D74003#1858144, @NoQ wrote:

That's a safe default behavior, but ideally you should see if the annotation on the function can be applied after inlining. Like, it isn't necessarily always applicable, but when it is, you might be able to improve coverage.

Do you want me to add a FIXME?

[NoQ]

In D74003#1858196, @xazax.hun wrote:

Do you want me to add a FIXME?

That'd be great, i think.

clang/lib/StaticAnalyzer/Checkers/PthreadLockChecker.cpp

 REGISTER_MAP_WITH_PROGRAMSTATE(DestroyRetVal, const MemRegion *, SymbolRef)
 
 void PthreadLockChecker::checkPostCall(const CallEvent &Call,
                                        CheckerContext &C) const {
   // An additional umbrella check that all functions modeled by this checker
   // are global C functions.
   // TODO: Maybe make this the default behavior of CallDescription
   // with exactly one identifier?
-  if (!Call.isGlobalCFunction())
+  // FIXME: Try to handle cases when the implementation was inlined rather
+  // than just giving up.
+  if (!Call.isGlobalCFunction() || C.wasInlined)
     return;
 
   if (const FnCheck *Callback = PThreadCallbacks.lookup(Call))
     (this->**Callback)(Call, C, CK_PthreadLockChecker);
   else if (const FnCheck *Callback = FuchsiaCallbacks.lookup(Call))
     (this->**Callback)(Call, C, CK_FuchsiaLockChecker);
   else if (const FnCheck *Callback = C11Callbacks.lookup(Call))
     (this->**Callback)(Call, C, CK_C11LockChecker);

clang/test/Analysis/fuchsia_lock_impl.c

+// RUN: %clang_analyze_cc1 -analyzer-checker=fuchsia.Lock -verify %s
+// expected-no-diagnostics
+typedef int spin_lock_t;
+
+void spin_lock(spin_lock_t *lock);
+int getCond();
+int spin_trylock(spin_lock_t *lock) {
+    if (getCond())
+        return 0;
+    return -1;
+}
+void spin_unlock(spin_lock_t *lock);
+
+spin_lock_t mtx;
+void no_crash() {
+  if (spin_trylock(&mtx) == 0)
+    spin_unlock(&mtx);
+}