[analyzer] Treat all struct values as regions (even rvalues).
This allows us to correctly symbolicate the fields of structs returned by
value, as well as get the proper 'this' value for when methods are called
on structs returned by value.
This does require a moderately ugly hack in the StoreManager: if we assign
a "struct value" to a struct region, that now appears as a Loc value being
bound to a region of struct type. We handle this by simply "dereferencing"
the struct value region, which should create a LazyCompoundVal.
This should fix recent crashes analyzing LLVM and on our internal buildbot.
<rdar://problem/12137950>
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@163066 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/include/clang/StaticAnalyzer/Core/PathSensitive/BasicValueFactory.h b/include/clang/StaticAnalyzer/Core/PathSensitive/BasicValueFactory.h
index b4a9de7..56a932b 100644
--- a/include/clang/StaticAnalyzer/Core/PathSensitive/BasicValueFactory.h
+++ b/include/clang/StaticAnalyzer/Core/PathSensitive/BasicValueFactory.h
@@ -90,6 +90,9 @@
/// Returns the type of the APSInt used to store values of the given QualType.
APSIntType getAPSIntType(QualType T) const {
assert(T->isIntegerType() || Loc::isLocType(T));
+ // Make sure all locations have the same representation in the analyzer.
+ if (Loc::isLocType(T))
+ T = Ctx.VoidPtrTy;
return APSIntType(Ctx.getTypeSize(T),
!T->isSignedIntegerOrEnumerationType());
}
diff --git a/include/clang/StaticAnalyzer/Core/PathSensitive/SVals.h b/include/clang/StaticAnalyzer/Core/PathSensitive/SVals.h
index e0b5f64..52e52e0 100644
--- a/include/clang/StaticAnalyzer/Core/PathSensitive/SVals.h
+++ b/include/clang/StaticAnalyzer/Core/PathSensitive/SVals.h
@@ -246,8 +246,16 @@
}
static inline bool isLocType(QualType T) {
+ // Why are record types included here? Because we want to make sure a
+ // record, even a record rvalue, is always represented with a region.
+ // This is especially necessary in C++, where you can call methods on
+ // struct prvalues, which then need to have a valid 'this' pointer.
+ //
+ // This necessitates a bit of extra hackery in the Store to deal with
+ // the case of binding a "struct value" into a struct region; in
+ // practice it just means "dereferencing" the value before binding.
return T->isAnyPointerType() || T->isBlockPointerType() ||
- T->isReferenceType();
+ T->isReferenceType() || T->isRecordType();
}
};
diff --git a/lib/StaticAnalyzer/Core/RegionStore.cpp b/lib/StaticAnalyzer/Core/RegionStore.cpp
index b3cf208..9634226 100644
--- a/lib/StaticAnalyzer/Core/RegionStore.cpp
+++ b/lib/StaticAnalyzer/Core/RegionStore.cpp
@@ -1744,6 +1744,26 @@
if (!RD->isCompleteDefinition())
return StoreRef(store, *this);
+ // Handle Loc values by automatically dereferencing the location.
+ // This is necessary because we treat all struct values as regions even if
+ // they are rvalues; we may then be asked to bind one of these
+ // "rvalue regions" to an actual struct region.
+ // (This is necessary for many of the test cases in array-struct-region.cpp.)
+ //
+ // This also handles the case of a struct argument passed by value to an
+ // inlined function. In this case, the C++ standard says that the value
+ // is copy-constructed into the parameter variable. However, the copy-
+ // constructor is processed before we actually know if we're going to inline
+ // the function, and thus we don't actually have the parameter's region
+ // available. Instead, we use a temporary-object region, then copy the
+ // bindings over by value.
+ //
+ // FIXME: This will be a problem when we handle the destructors of
+ // temporaries; the inlined function will modify the parameter region,
+ // but the destructor will act on the temporary region.
+ if (const loc::MemRegionVal *MRV = dyn_cast<loc::MemRegionVal>(&V))
+ V = getBinding(store, *MRV);
+
// Handle lazy compound values and symbolic values.
if (isa<nonloc::LazyCompoundVal>(V) || isa<nonloc::SymbolVal>(V))
return BindAggregate(store, R, V);
diff --git a/lib/StaticAnalyzer/Core/SymbolManager.cpp b/lib/StaticAnalyzer/Core/SymbolManager.cpp
index c21df4c..65356a9 100644
--- a/lib/StaticAnalyzer/Core/SymbolManager.cpp
+++ b/lib/StaticAnalyzer/Core/SymbolManager.cpp
@@ -365,9 +365,6 @@
if (T->isIntegerType())
return T->isScalarType();
- if (T->isRecordType() && !T->isUnionType())
- return true;
-
return false;
}
diff --git a/test/Analysis/array-struct-region.cpp b/test/Analysis/array-struct-region.cpp
new file mode 100644
index 0000000..3581566
--- /dev/null
+++ b/test/Analysis/array-struct-region.cpp
@@ -0,0 +1,87 @@
+// RUN: %clang_cc1 -analyze -analyzer-checker=core,alpha.core,debug.ExprInspection -verify -x c %s
+// RUN: %clang_cc1 -analyze -analyzer-checker=core,alpha.core,debug.ExprInspection -verify -x c++ -analyzer-config c++-inlining=constructors %s
+
+void clang_analyzer_eval(int);
+
+struct S {
+ int field;
+
+#if __cplusplus
+ const struct S *getThis() const { return this; }
+#endif
+};
+
+struct S getS();
+
+
+void testAssignment() {
+ struct S s = getS();
+
+ if (s.field != 42) return;
+ clang_analyzer_eval(s.field == 42); // expected-warning{{TRUE}}
+
+ s.field = 0;
+ clang_analyzer_eval(s.field == 0); // expected-warning{{TRUE}}
+
+#if __cplusplus
+ clang_analyzer_eval(s.getThis() == &s); // expected-warning{{TRUE}}
+#endif
+}
+
+
+void testImmediateUse() {
+ int x = getS().field;
+
+ if (x != 42) return;
+ clang_analyzer_eval(x == 42); // expected-warning{{TRUE}}
+
+#if __cplusplus
+ clang_analyzer_eval((void *)getS().getThis() == (void *)&x); // expected-warning{{FALSE}}
+#endif
+}
+
+int getConstrainedField(struct S s) {
+ if (s.field != 42) return 42;
+ return s.field;
+}
+
+int getAssignedField(struct S s) {
+ s.field = 42;
+ return s.field;
+}
+
+void testArgument() {
+ clang_analyzer_eval(getConstrainedField(getS()) == 42); // expected-warning{{TRUE}}
+ clang_analyzer_eval(getAssignedField(getS()) == 42); // expected-warning{{TRUE}}
+}
+
+
+//--------------------
+// C++-only tests
+//--------------------
+
+#if __cplusplus
+void testReferenceAssignment() {
+ const S &s = getS();
+
+ if (s.field != 42) return;
+ clang_analyzer_eval(s.field == 42); // expected-warning{{TRUE}}
+
+ clang_analyzer_eval(s.getThis() == &s); // expected-warning{{TRUE}}
+}
+
+
+int getConstrainedFieldRef(const S &s) {
+ if (s.field != 42) return 42;
+ return s.field;
+}
+
+bool checkThis(const S &s) {
+ return s.getThis() == &s;
+}
+
+void testReferenceArgument() {
+ clang_analyzer_eval(getConstrainedFieldRef(getS()) == 42); // expected-warning{{TRUE}}
+ clang_analyzer_eval(checkThis(getS())); // expected-warning{{TRUE}}
+}
+#endif
diff --git a/test/Analysis/reference.cpp b/test/Analysis/reference.cpp
index 4a2cbb8..ce0ee8e 100644
--- a/test/Analysis/reference.cpp
+++ b/test/Analysis/reference.cpp
@@ -116,8 +116,11 @@
struct S { int &x; };
- extern S *getS();
- clang_analyzer_eval(&getS()->x != 0); // expected-warning{{TRUE}}
+ extern S getS();
+ clang_analyzer_eval(&getS().x != 0); // expected-warning{{TRUE}}
+
+ extern S *getSP();
+ clang_analyzer_eval(&getSP()->x != 0); // expected-warning{{TRUE}}
}
@@ -150,10 +153,3 @@
return *x; // should warn here!
}
}
-
-void testReferenceFieldAddress() {
- struct S { int &x; };
-
- extern S getS();
- clang_analyzer_eval(&getS().x != 0); // expected-warning{{UNKNOWN}}
-}
