[lldb] Fix TestWithLimitDebugInfo.py

The test was broken (in the sense that it was not testing what it was
supposed to test) in two ways:
- a Makefile refactor caused it to stop being built with
  -flimit-debug-info
- clang's constructor homing changed the "home" of the type

This patch fixes the Makefile, and modifies the source code to produce
the same result with both type homing strategies. Due to constructor
homing I had to use a different implicitly-defined function for the test
-- I chose the assignment operator.

I also added some sanity checks to the test to ensure that the test is
indeed operating on limited debug info.

Author: labath

lldb/test/API/lang/cpp/limit-debug-info/Makefile

@@ -1,5 +1,5 @@
 CXX_SOURCES = main.cpp derived.cpp base.cpp
 
-CFLAGS_EXTRAS := $(LIMIT_DEBUG_INFO_FLAGS)
+CFLAGS_EXTRAS = $(LIMIT_DEBUG_INFO_FLAGS)
 
 include Makefile.rules

lldb/test/API/lang/cpp/limit-debug-info/TestWithLimitDebugInfo.py

@@ -8,10 +8,12 @@ class TestWithLimitDebugInfo(TestBase):
 
     mydir = TestBase.compute_mydir(__file__)
 
-    @skipIf(debug_info=no_match(["dwarf"]))
+    @add_test_categories(["dwarf", "dwo"])
     def test_limit_debug_info(self):
         self.build()
 
+        self._check_info_is_limited()
+
         src_file = os.path.join(self.getSourceDir(), "main.cpp")
         src_file_spec = lldb.SBFileSpec(src_file)
         self.assertTrue(src_file_spec.IsValid(), "breakpoint file")
@@ -52,6 +54,12 @@ def test_limit_debug_info(self):
         self.assertTrue(
             v2.IsValid(),
             "'expr this' results in a valid SBValue object")
-        self.assertTrue(
-            v2.GetError().Success(),
+        self.assertSuccess(
+            v2.GetError(),
             "'expr this' succeeds without an error.")
+
+    def _check_info_is_limited(self):
+        target = self.dbg.CreateTarget(self.getBuildArtifact("main.o"))
+        self.assertTrue(target.IsValid())
+        Foo = target.FindFirstType("Foo")
+        self.assertFalse(Foo.IsValid())

lldb/test/API/lang/cpp/limit-debug-info/base.cpp

@@ -1,5 +1,7 @@
 #include "base.h"
 
+FooNS::FooNS() : x(12345) {}
+
 void FooNS::bar() {
     x = 54321;
 }

lldb/test/API/lang/cpp/limit-debug-info/base.h

@@ -5,6 +5,8 @@ class FooNS
     virtual char baz() = 0;
 
 protected:
+    FooNS();
+
     int x;
 };
 

lldb/test/API/lang/cpp/limit-debug-info/derived.cpp

@@ -1,5 +1,10 @@
 #include "derived.h"
 
+Foo foo1;
+Foo foo2;
+
+Foo::Foo() { a = 12345; }
+
 char Foo::baz() {
     return (char)(x&0xff);
 }

lldb/test/API/lang/cpp/limit-debug-info/derived.h

@@ -3,11 +3,17 @@
 class Foo : public FooNS
 {
 public:
-    Foo() {
-        a = 12345;
+    Foo();
+
+    // Deliberately defined by hand.
+    Foo &operator=(const Foo &rhs) {
+      a = rhs.a;
+      return *this;
     }
 
     char baz() override;
     int a;
 };
 
+extern Foo foo1;
+extern Foo foo2;

lldb/test/API/lang/cpp/limit-debug-info/main.cpp

@@ -1,7 +1,8 @@
 #include "derived.h"
 
 int main() {
-    Foo f; // break here
-    f.bar();
-    return f.baz();
+    foo1 = foo2; // break here
+
+    foo1.bar();
+    return foo1.baz();
 }