[PATCH] Fix static analyzer crash when casting from an incomplete type
Pavel Labath
labath at google.com
Wed Jun 19 05:00:35 PDT 2013
When doing a reinterpret+dynamic cast from an incomplete type, the analyzer
would crash (bug #16308). This fix makes the dynamic cast evaluator ignore
incomplete types, as they can never be used in a dynamic_cast. Also adding a
regression test.
http://llvm-reviews.chandlerc.com/D1006
Files:
lib/StaticAnalyzer/Core/Store.cpp
test/Analysis/derived-to-base.cpp
Index: lib/StaticAnalyzer/Core/Store.cpp
===================================================================
--- lib/StaticAnalyzer/Core/Store.cpp
+++ lib/StaticAnalyzer/Core/Store.cpp
@@ -325,7 +325,9 @@
if (MRClass == TargetClass)
return loc::MemRegionVal(MR);
- if (!TargetType->isVoidType()) {
+ // We skip over incomplete types. They must be the result of an earlier
+ // reinterpret_cast, as one cannot dynamically cast from an incomplete type.
+ if (!TargetType->isVoidType() && MRClass->isCompleteDefinition()) {
// Static upcasts are marked as DerivedToBase casts by Sema, so this will
// only happen when multiple or virtual inheritance is involved.
CXXBasePaths Paths(/*FindAmbiguities=*/false, /*RecordPaths=*/true,
Index: test/Analysis/derived-to-base.cpp
===================================================================
--- test/Analysis/derived-to-base.cpp
+++ test/Analysis/derived-to-base.cpp
@@ -450,3 +450,28 @@
}
};
+namespace Bug16309 {
+ struct Incomplete;
+
+ struct Base { virtual ~Base(); };
+
+ struct Derived : public Base { int x; };
+
+ void* f(Incomplete *i) {
+ Base *b = reinterpret_cast<Base *>(i);
+ // This used to crash because of the reinterpret_cast above.
+ Derived *d = dynamic_cast<Derived *>(b);
+ return d;
+ }
+
+ // And check that reinterpret+dynamic casts work correctly after the fix.
+ void g() {
+ Derived d;
+ d.x = 47;
+ Base *b = &d;
+ Incomplete *i = reinterpret_cast<Incomplete *>(b);
+ Base *b2 = reinterpret_cast<Base *>(i);
+ Derived *d2 = dynamic_cast<Derived *>(b2);
+ clang_analyzer_eval(d2->x == 47); // expected-warning{{TRUE}}
+ }
+}
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