[analyzer] Tweak the UnreachableCode checker to not warning about unreachable default blocks. Patch by Cyril Roelandt!
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@151709 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/StaticAnalyzer/Checkers/UnreachableCodeChecker.cpp b/lib/StaticAnalyzer/Checkers/UnreachableCodeChecker.cpp
index 2b550df..8ac785c 100644
--- a/lib/StaticAnalyzer/Checkers/UnreachableCodeChecker.cpp
+++ b/lib/StaticAnalyzer/Checkers/UnreachableCodeChecker.cpp
@@ -116,6 +116,14 @@
if (CB->size() > 0 && isInvalidPath(CB, *PM))
continue;
+ // It is good practice to always have a "default" label in a "switch", even
+ // if we should never get there. It can be used to detect errors, for
+ // instance. Unreachable code directly under a "default" label is therefore
+ // likely to be a false positive.
+ if (const Stmt *label = CB->getLabel())
+ if (label->getStmtClass() == Stmt::DefaultStmtClass)
+ continue;
+
// Special case for __builtin_unreachable.
// FIXME: This should be extended to include other unreachable markers,
// such as llvm_unreachable.
diff --git a/test/Analysis/unreachable-code-path.c b/test/Analysis/unreachable-code-path.c
index da14f4c..48a3462 100644
--- a/test/Analysis/unreachable-code-path.c
+++ b/test/Analysis/unreachable-code-path.c
@@ -122,3 +122,20 @@
goto d;
f: ;
}
+
+// test11: we can actually end up in the default case, even if it is not
+// obvious: there might be something wrong with the given argument.
+enum foobar { FOO, BAR };
+extern void error();
+void test11(enum foobar fb) {
+ switch (fb) {
+ case FOO:
+ break;
+ case BAR:
+ break;
+ default:
+ error(); // no-warning
+ return;
+ error(); // expected-warning {{never executed}}
+ }
+}
