[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>

llvm-svn: 163066

1 files changed, 87 insertions, 0 deletions

diff --git a/clang/test/Analysis/array-struct-region.cpp b/clang/test/Analysis/array-struct-region.cpp
new file mode 100644
index 00000000000..3581566bdcc
--- /dev/null
+++ b/clang/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