[PATCH 2/2] Thread-safety: Add test for -Wthread-safety check for C.

[Alex Wang]

This commit adds test to the -Wthread-safety check for C code.

Co-authored-by: Ethan Jackson <ethan at nicira.com>
Signed-off-by: Alex Wang <alexw at nicira.com>

Index: warn-thread-safety-analysis.c
===================================================================
--- warn-thread-safety-analysis.c	(revision 0)
+++ warn-thread-safety-analysis.c	(revision 0)
@@ -0,0 +1,132 @@
+// RUN: %clang -fsyntax-only -verify -Wthread-safety -Wthread-safety-beta -fcxx-exceptions %s
+
+#include <assert.h>
+
+#define LOCKABLE            __attribute__ ((lockable))
+#define SCOPED_LOCKABLE     __attribute__ ((scoped_lockable))
+#define GUARDED_BY(x)       __attribute__ ((guarded_by(x)))
+#define GUARDED_VAR         __attribute__ ((guarded_var))
+#define PT_GUARDED_BY(x)    __attribute__ ((pt_guarded_by(x)))
+#define PT_GUARDED_VAR      __attribute__ ((pt_guarded_var))
+#define ACQUIRED_AFTER(...) __attribute__ ((acquired_after(__VA_ARGS__)))
+#define ACQUIRED_BEFORE(...) __attribute__ ((acquired_before(__VA_ARGS__)))
+#define EXCLUSIVE_LOCK_FUNCTION(...)    __attribute__ ((exclusive_lock_function(__VA_ARGS__)))
+#define SHARED_LOCK_FUNCTION(...)       __attribute__ ((shared_lock_function(__VA_ARGS__)))
+#define ASSERT_EXCLUSIVE_LOCK(...)      __attribute__ ((assert_exclusive_lock(__VA_ARGS__)))
+#define ASSERT_SHARED_LOCK(...)         __attribute__ ((assert_shared_lock(__VA_ARGS__)))
+#define EXCLUSIVE_TRYLOCK_FUNCTION(...) __attribute__ ((exclusive_trylock_function(__VA_ARGS__)))
+#define SHARED_TRYLOCK_FUNCTION(...)    __attribute__ ((shared_trylock_function(__VA_ARGS__)))
+#define UNLOCK_FUNCTION(...)            __attribute__ ((unlock_function(__VA_ARGS__)))
+#define LOCK_RETURNED(x)    __attribute__ ((lock_returned(x)))
+#define LOCKS_EXCLUDED(...) __attribute__ ((locks_excluded(__VA_ARGS__)))
+#define EXCLUSIVE_LOCKS_REQUIRED(...) \
+  __attribute__ ((exclusive_locks_required(__VA_ARGS__)))
+#define SHARED_LOCKS_REQUIRED(...) \
+  __attribute__ ((shared_locks_required(__VA_ARGS__)))
+#define NO_THREAD_SAFETY_ANALYSIS  __attribute__ ((no_thread_safety_analysis))
+
+// Define the mutex struct.
+// Simplified only for test purpose.
+struct LOCKABLE Mutex {};
+
+struct Foo {
+  struct Mutex *mu_;
+};
+
+// Define mutex lock/unlock functions.
+void mutex_exclusive_lock(struct Mutex *mu) EXCLUSIVE_LOCK_FUNCTION(mu) {
+}
+
+void mutex_shared_lock(struct Mutex *mu) SHARED_LOCK_FUNCTION(mu) {
+}
+
+void mutex_unlock(struct Mutex *mu) UNLOCK_FUNCTION(mu) {
+}
+
+// Define global variables.
+struct Mutex mu1;
+struct Mutex mu2 ACQUIRED_AFTER(mu1);
+struct Foo foo_ = {&mu1};
+int a_ GUARDED_BY(foo_.mu_);
+int *b_ PT_GUARDED_BY(foo_.mu_) = &a_;
+int c_ GUARDED_VAR;
+int *d_ PT_GUARDED_VAR = &c_;
+
+// Define test functions.
+int Foo_fun1(int i) SHARED_LOCKS_REQUIRED(mu2) EXCLUSIVE_LOCKS_REQUIRED(mu1) {
+  return i;
+}
+
+int Foo_fun2(int i) EXCLUSIVE_LOCKS_REQUIRED(mu2) SHARED_LOCKS_REQUIRED(mu1) {
+  return i;
+}
+
+int Foo_func3(int i) LOCKS_EXCLUDED(mu1, mu2) {
+  return i;
+}
+
+static int Bar_fun1(int i) EXCLUSIVE_LOCKS_REQUIRED(mu1) {
+  return i;
+}
+
+void set_value(int *a, int value) EXCLUSIVE_LOCKS_REQUIRED(foo_.mu_) {
+  *a = value;
+}
+
+int get_value(int *p) SHARED_LOCKS_REQUIRED(foo_.mu_){
+  return *p;
+}
+
+int main() {
+
+  Foo_fun1(1); // \
+      // expected-warning{{calling function 'Foo_fun1' requires shared lock on 'mu2'}}
+      // expected-warning{{calling function 'Foo_fun1' requires exclusive lock on 'mu1'}}
+
+  mutex_exclusive_lock(&mu1);
+  mutex_shared_lock(&mu2);
+  Foo_fun1(1);
+
+  mutex_shared_lock(&mu1);  // \
+      // expected-warning{{locking 'mu1' that is already locked}}
+  mutex_unlock(&mu1);
+  mutex_unlock(&mu2);
+  mutex_shared_lock(&mu1);
+  mutex_exclusive_lock(&mu2);
+  Foo_fun2(2);
+
+  mutex_unlock(&mu2);
+  mutex_unlock(&mu1);
+  mutex_exclusive_lock(&mu1);
+  Bar_fun1(3);
+  mutex_unlock(&mu1);
+
+  mutex_exclusive_lock(&mu1);
+  Foo_func3(4);  // \
+      // expected-warning{{cannot call function 'Foo_func3' while mutex 'mu1' is locked}}
+  mutex_unlock(&mu1);
+
+  Foo_func3(5);
+
+  set_value(&a_, 0);  // \
+      // expected-warning{{calling function 'setA' requires exclusive lock on 'foo_.mu_'}}
+  get_value(b_);  // \
+      // expected-warning{{calling function 'getB' requires shared lock on 'foo_.mu_'}}
+  mutex_exclusive_lock(foo_.mu_);
+  set_value(&a_, 1);
+  mutex_unlock(foo_.mu_);
+  mutex_shared_lock(foo_.mu_);
+  assert(get_value(b_) == 1);
+  mutex_unlock(foo_.mu_);
+
+  c_ = 0;  // \
+      // expected-warning{{writing variable 'c_' requires locking any mutex exclusively}}
+  assert(*d_ == 0);  // \
+      // expected-warning{{reading the value pointed to by 'd_' requires locking any mutex}}
+  mutex_exclusive_lock(foo_.mu_);
+  c_ = 1;
+  assert(*d_ == 1);
+  mutex_unlock(foo_.mu_);
+
+  return 0;
+}