[CFG] Add an option to expand CXXDefaultInitExpr into aggregate initialization

This is useful for clients that are relying on linearized CFGs for evaluating
subexpressions and want the default initializer to be evaluated properly.

The upcoming lifetime analysis is using this but it might also be useful
for the static analyzer at some point.

Differential Revision: https://reviews.llvm.org/D71642

1 files changed, 28 insertions, 0 deletions

diff --git a/clang/test/Analysis/aggrinit-cfg-output.cpp b/clang/test/Analysis/aggrinit-cfg-output.cpp
new file mode 100644
index 00000000000..2e95a7f9e24
--- /dev/null
+++ b/clang/test/Analysis/aggrinit-cfg-output.cpp
@@ -0,0 +1,28 @@
+// RUN: %clang_cc1 -analyze -analyzer-checker=debug.DumpCFG -analyzer-config cfg-expand-default-aggr-inits=true %s > %t 2>&1
+// RUN: FileCheck --input-file=%t %s
+
+static char a[] = "foobar";
+
+struct StringRef {
+  const char *member = nullptr;
+  int len = 3;
+};
+
+int main() {
+  StringRef s{a};
+  (void)s;
+}
+
+// CHECK: [B1]
+// CHECK-NEXT:   1: a
+// CHECK-NEXT:   2: [B1.1] (ImplicitCastExpr, ArrayToPointerDecay, char *)
+// CHECK-NEXT:   3: [B1.2] (ImplicitCastExpr, NoOp, const char *)
+// CHECK-NEXT:   4: 3
+// CHECK-NEXT:   5: 
+// CHECK-NEXT:   6: {[B1.1]}
+// CHECK-NEXT:   7: StringRef s{a};
+// CHECK-NEXT:   8: s
+// CHECK-NEXT:   9: (void)[B1.8] (CStyleCastExpr, ToVoid, void)
+// CHECK-NEXT:   Preds (1): B2
+// CHECK-NEXT:   Succs (1): B0
+