Fix handling of CreateTemplateParameterList when there is an empty pack

Summary:
When we are creating a ClassTemplateSpecializationDecl in ParseTypeFromDWARF(...) we are not handling the case where variadic pack is empty in the specialization. This patch handles that case and adds a test to prevent future regressions.

Differential Revision: https://reviews.llvm.org/D57363

llvm-svn: 352677

3 files changed, 37 insertions, 0 deletions

diff --git a/lldb/packages/Python/lldbsuite/test/expression_command/class_template_specialization_empty_pack/Makefile b/lldb/packages/Python/lldbsuite/test/expression_command/class_template_specialization_empty_pack/Makefile
new file mode 100644
index 00000000000..8a7102e347a
--- /dev/null
+++ b/lldb/packages/Python/lldbsuite/test/expression_command/class_template_specialization_empty_pack/Makefile
@@ -0,0 +1,5 @@
+LEVEL = ../../make
+
+CXX_SOURCES := main.cpp
+
+include $(LEVEL)/Makefile.rules
diff --git a/lldb/packages/Python/lldbsuite/test/expression_command/class_template_specialization_empty_pack/TestClassTemplateSpecializationParametersHandling.py b/lldb/packages/Python/lldbsuite/test/expression_command/class_template_specialization_empty_pack/TestClassTemplateSpecializationParametersHandling.py
new file mode 100644
index 00000000000..d1974d05a24
--- /dev/null
+++ b/lldb/packages/Python/lldbsuite/test/expression_command/class_template_specialization_empty_pack/TestClassTemplateSpecializationParametersHandling.py
@@ -0,0 +1,23 @@
+"""
+Test Expression Parser code gen for ClassTemplateSpecializationDecl to insure
+that we generate a TemplateTypeParmDecl in the TemplateParameterList for empty
+variadic packs.
+"""
+
+
+import lldb
+from lldbsuite.test.decorators import *
+from lldbsuite.test.lldbtest import *
+from lldbsuite.test import lldbutil
+
+class TestClassTemplateSpecializationParametersHandling(TestBase):
+
+    mydir = TestBase.compute_mydir(__file__)
+
+    def test_class_template_specialization(self):
+        self.build()
+
+        lldbutil.run_to_source_breakpoint(self, '// break here',
+                lldb.SBFileSpec("main.cpp", False))
+
+        self.expect("expr -u 0 -- b.foo()", substrs=['$0 = 1'])
diff --git a/lldb/packages/Python/lldbsuite/test/expression_command/class_template_specialization_empty_pack/main.cpp b/lldb/packages/Python/lldbsuite/test/expression_command/class_template_specialization_empty_pack/main.cpp
new file mode 100644
index 00000000000..bc831604aed
--- /dev/null
+++ b/lldb/packages/Python/lldbsuite/test/expression_command/class_template_specialization_empty_pack/main.cpp
@@ -0,0 +1,9 @@
+template <typename N, class... P>
+struct A {
+    int foo() { return 1;}
+};
+
+int main() {
+  A<int> b;
+  return b.foo(); // break here
+}