r337212 - [analyzer] Fix GCDAntipatternChecker to only fire when the semaphore is initialized to zero

[George Karpenkov via cfe-commits]

Author: george.karpenkov
Date: Mon Jul 16 13:32:57 2018
New Revision: 337212

URL: http://llvm.org/viewvc/llvm-project?rev=337212&view=rev
Log:
[analyzer] Fix GCDAntipatternChecker to only fire when the semaphore is initialized to zero

Initializing a semaphore with a different constant most likely signals a different intent

rdar://41802552

Differential Revision: https://reviews.llvm.org/D48911

Modified:
    cfe/trunk/lib/StaticAnalyzer/Checkers/GCDAntipatternChecker.cpp
    cfe/trunk/test/Analysis/gcdantipatternchecker_test.m

Modified: cfe/trunk/lib/StaticAnalyzer/Checkers/GCDAntipatternChecker.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/StaticAnalyzer/Checkers/GCDAntipatternChecker.cpp?rev=337212&r1=337211&r2=337212&view=diff
==============================================================================
--- cfe/trunk/lib/StaticAnalyzer/Checkers/GCDAntipatternChecker.cpp (original)
+++ cfe/trunk/lib/StaticAnalyzer/Checkers/GCDAntipatternChecker.cpp Mon Jul 16 13:32:57 2018
@@ -93,7 +93,9 @@ static bool isTest(const Decl *D) {
 static auto findGCDAntiPatternWithSemaphore() -> decltype(compoundStmt()) {
 
   const char *SemaphoreBinding = "semaphore_name";
-  auto SemaphoreCreateM = callExpr(callsName("dispatch_semaphore_create"));
+  auto SemaphoreCreateM = callExpr(allOf(
+      callsName("dispatch_semaphore_create"),
+      hasArgument(0, ignoringParenCasts(integerLiteral(equals(0))))));
 
   auto SemaphoreBindingM = anyOf(
       forEachDescendant(

Modified: cfe/trunk/test/Analysis/gcdantipatternchecker_test.m
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Analysis/gcdantipatternchecker_test.m?rev=337212&r1=337211&r2=337212&view=diff
==============================================================================
--- cfe/trunk/test/Analysis/gcdantipatternchecker_test.m (original)
+++ cfe/trunk/test/Analysis/gcdantipatternchecker_test.m Mon Jul 16 13:32:57 2018
@@ -333,3 +333,13 @@ void dispatch_group_and_semaphore_use(My
   }];
   dispatch_semaphore_wait(sema1, 100); // expected-warning{{Waiting on a callback using a semaphore}}
 }
+
+void no_warn_on_nonzero_semaphore(MyInterface1 *M) {
+  dispatch_semaphore_t sema1 = dispatch_semaphore_create(1);
+
+  [M acceptBlock:^{
+      dispatch_semaphore_signal(sema1);
+  }];
+  dispatch_semaphore_wait(sema1, 100); // no-warning
+}
+