[analyzer] Be careful about LazyCompoundVals, which may be for the first field.

We use LazyCompoundVals to avoid copying the contents of structs and arrays
around in the store, and when we need to pass a struct around that already
has a LazyCompoundVal we just use the original one. However, it's possible
that the first field of a struct may have a LazyCompoundVal of its own, and
we currently can't distinguish a LazyCompoundVal for the first element of a
struct from a LazyCompoundVal for the entire struct. In this case we should
just drop the optimization and make a new LazyCompoundVal that encompasses
the old one.

PR13264 / <rdar://problem/11802440>

llvm-svn: 159866

1 files changed, 37 insertions, 2 deletions

diff --git a/clang/test/Analysis/array-struct-region.c b/clang/test/Analysis/array-struct-region.c
index c1eddcdd217..ddb9f4b1167 100644
--- a/clang/test/Analysis/array-struct-region.c
+++ b/clang/test/Analysis/array-struct-region.c
@@ -1,5 +1,5 @@
-// RUN: %clang_cc1 -analyze -analyzer-checker=core,experimental.core,debug.ExprInspection -analyzer-store=region -analyzer-constraints=basic -verify %s
-// RUN: %clang_cc1 -analyze -analyzer-checker=core,experimental.core,debug.ExprInspection -analyzer-store=region -analyzer-constraints=range -verify %s
+// RUN: %clang_cc1 -analyze -analyzer-checker=core,experimental.core,debug.ExprInspection -analyzer-store=region -analyzer-constraints=basic -analyzer-ipa=all -verify %s
+// RUN: %clang_cc1 -analyze -analyzer-checker=core,experimental.core,debug.ExprInspection -analyzer-store=region -analyzer-constraints=range -analyzer-ipa=all -verify %s
 
 void clang_analyzer_eval(int);
 
@@ -57,3 +57,38 @@ void struct_as_array() {
   clang_analyzer_eval(p->y == 5); // expected-warning{{TRUE}}
 }
 
+
+// PR13264 / <rdar://problem/11802440>
+struct point { int x; int y; };
+struct circle { struct point o; int r; };
+struct circle get_circle() {
+  struct circle result;
+  result.r = 5;
+  result.o = (struct point){0, 0};
+  return result;
+}
+
+void struct_in_struct() {
+  struct circle c;
+  c = get_circle();
+  // This used to think c.r was undefined because c.o is a LazyCompoundVal.
+  clang_analyzer_eval(c.r == 5); // expected-warning{{TRUE}}
+}
+
+// We also test with floats because we don't model floats right now,
+// and the original bug report used a float.
+struct circle_f { struct point o; float r; };
+struct circle_f get_circle_f() {
+  struct circle_f result;
+  result.r = 5.0;
+  result.o = (struct point){0, 0};
+  return result;
+}
+
+float struct_in_struct_f() {
+  struct circle_f c;
+  c = get_circle_f();
+
+  return c.r; // no-warning
+}
+