[analyzer] Move function declarations of PthreadLockChecker's tests to a separate system-like header

[a.sidorin]

Summary

Regions passed to pthread* functions are invalidated in tests because the call is evaluated conservatively and declarations are not located in system header. This patch creates a system-like header with declarations previously located in test file.

[krememek]

This feels like a big hammer to wield just to prevent the conservative invalidation done by the static analyzer for calls to functions whose bodies are not available.

I feel like a more general approach might be to provide new hooks for checkers to provide hints to the core analyzer engine. For example, a callback that indicates whether or not invalidation should take place. That seems like a solution that could be utilized by other checkers besides just this one, and would allow checkers to opt into this with very little code.

[jordan_rose]

I tend to agree. eval::Call has the downside that only one checker can provide an implementation (since it controls the return value). But I'm also surprised that the example is failing—because the pthread_* methods are declared in system headers, only globals declared in system headers should be invalidated.

[a.sidorin]

You're right Jordan. I have made wrong suggestions from my investigation. It should be tests that should be fixed, not the checker itself.

[a.sidorin]

Fix tests, not the checker itself. Sorry for mistake and thanks to Jordan for help.

[jordan_rose]

Looks good, committed in r217515.

test/Analysis/Inputs/system-header-simulator-for-pthread-lock.h

+// Like the compiler, the static analyzer treats some functions differently if
+// they come from a system header -- for example, pthread_mutex* functions
+// should not invalidate regions of their arguments.
+#pragma clang system_header
+
+typedef struct {
+  void  *foo;
+} pthread_mutex_t;
+
+typedef struct {
+  void  *foo;
+} pthread_mutexattr_t;
+
+typedef struct {
+  void  *foo;
+} lck_grp_t;
+
+typedef pthread_mutex_t lck_mtx_t;
+
+extern int pthread_mutex_lock(pthread_mutex_t *);
+extern int pthread_mutex_unlock(pthread_mutex_t *);
+extern int pthread_mutex_trylock(pthread_mutex_t *);
+extern int pthread_mutex_destroy(pthread_mutex_t *);
+extern int pthread_mutex_init(pthread_mutex_t  *mutex, const pthread_mutexattr_t *mutexattr);
+extern int lck_mtx_lock(lck_mtx_t *);
+extern int lck_mtx_unlock(lck_mtx_t *);
+extern int lck_mtx_try_lock(lck_mtx_t *);
+extern void lck_mtx_destroy(lck_mtx_t *lck, lck_grp_t *grp);

test/Analysis/pthreadlock.c

 
 // Tests performing normal locking patterns and wrong locking orders
 
-typedef struct {
-  void  *foo;
-} pthread_mutex_t;
-
-typedef struct {
-  void  *foo;
-} pthread_mutexattr_t;
-
-typedef struct {
-  void  *foo;
-} lck_grp_t;
-
-typedef pthread_mutex_t lck_mtx_t;
-
-extern int pthread_mutex_lock(pthread_mutex_t *);
-extern int pthread_mutex_unlock(pthread_mutex_t *);
-extern int pthread_mutex_trylock(pthread_mutex_t *);
-extern int pthread_mutex_destroy(pthread_mutex_t *);
-extern int pthread_mutex_init(pthread_mutex_t  *mutex, const pthread_mutexattr_t *mutexattr);
-extern int lck_mtx_lock(lck_mtx_t *);
-extern int lck_mtx_unlock(lck_mtx_t *);
-extern int lck_mtx_try_lock(lck_mtx_t *);
-extern void lck_mtx_destroy(lck_mtx_t *lck, lck_grp_t *grp);
+#include "Inputs/system-header-simulator-for-pthread-lock.h"
 
 pthread_mutex_t mtx1, mtx2;
+pthread_mutex_t *pmtx;
 lck_mtx_t lck1, lck2;
 lck_grp_t grp1;
 

 }
 
 void
+ok21(void) {
+  pthread_mutex_lock(pmtx);    // no-warning
+  pthread_mutex_unlock(pmtx);  // no-warning
+}
+
+void
+ok22(void) {
+  pthread_mutex_lock(pmtx);    // no-warning
+  pthread_mutex_unlock(pmtx);  // no-warning
+  pthread_mutex_lock(pmtx);    // no-warning
+  pthread_mutex_unlock(pmtx);  // no-warning
+}
+
+
+void
 bad1(void)
 {
   pthread_mutex_lock(&mtx1);  // no-warning