Don't take the address of an xvalue when printing an expr result

Summary:
If we have an xvalue here, we will always hit the `err_typecheck_invalid_lvalue_addrof` error
in 'Sema::CheckAddressOfOperand' when trying to take the address of the result. This patch
uses the fallback code path where we store the result in a local variable instead when we hit
this case.

Fixes rdar://problem/40613277

Reviewers: jingham, vsk

Reviewed By: vsk

Subscribers: vsk, friss, lldb-commits

Differential Revision: https://reviews.llvm.org/D48303

llvm-svn: 336582

1 files changed, 12 insertions, 0 deletions

diff --git a/lldb/packages/Python/lldbsuite/test/expression_command/xvalue/main.cpp b/lldb/packages/Python/lldbsuite/test/expression_command/xvalue/main.cpp
new file mode 100644
index 00000000000..556c63f2b44
--- /dev/null
+++ b/lldb/packages/Python/lldbsuite/test/expression_command/xvalue/main.cpp
@@ -0,0 +1,12 @@
+struct Tmp
+{
+  int data = 1234;
+};
+
+Tmp foo() { return Tmp(); }
+
+int main(int argc, char const *argv[])
+{
+  int something = foo().data;
+  return 0; // Break here
+}