[lldb][test] TestDataFormatterCpp.py: add test-case for member function pointer format

[Michael137]

Summary

This patch adds a test for formatting of member function pointers.
This was split from D145242 and D145241, which caused
this test case to fail on Windows buildbots.

I split this out in order to make sure that this indeed works on Windows
without the above patches.

[labath]

lldb/test/API/functionalities/data-formatter/data-formatter-cpp/TestDataFormatterCpp.py

301

If this godbolt is right, then this won't work. Encoding of member pointers is abi-dependant, and it seems that MSVC encodes them as regular pointers to thunk functions (instead of these fancy tagged unions).

Come to think of it... I'm not sure why everyone doesn't do it that way...

[Michael137]

lldb/test/API/functionalities/data-formatter/data-formatter-cpp/TestDataFormatterCpp.py

301

Ah good point. Testing this here in this patch isn't necessary anyway. I'll add it back in the follow-up patches

[Michael137]

• Remove virtual function pointer test for now

[labath]

In D145487#4174832, @Michael137 wrote:

• Remove virtual function pointer test for now

You can keep it in, I think. Just don't assert the value of the last byte of the pointer.

[Michael137]

• Add back simplified virtual function ptr assertion

[Michael137]

Ok it looks like this is still failing on Windows...
I can't repro it on my Windows machine either so I'll split this test out and skip it

lldb/test/API/functionalities/data-formatter/data-formatter-cpp/TestDataFormatterCpp.py

def test_with_run_command(self):
         # want
         self.expect("frame variable iAmInt --format hex",
                     substrs=['(int) iAmInt = 0x00000001'])
         self.expect(
             "frame variable iAmInt",
             matching=False,
             substrs=['(int) iAmInt = 0x00000001'])
         self.expect("frame variable iAmInt", substrs=['(int) iAmInt = 1'])
+
+        # FIXME: don't format pointer to members as bytes, but rather as regular pointers
+        self.expect(
+            "frame variable member_ptr",
+            patterns=['member_ptr = [0-9a-z]{2}\s'])
+        self.expect(
+            "frame variable member_func_ptr",
+            patterns=['member_func_ptr = [0-9a-z]{2}\s'])
+        self.expect(
+            "frame variable ref_to_member_func_ptr",
+            patterns=['ref_to_member_func_ptr = [0-9a-z]{2}\s'])
+        self.expect(
+            "frame variable virt_member_func_ptr",
+            patterns=['virt_member_func_ptr = [0-9a-z]{2}\s'])

lldb/test/API/functionalities/data-formatter/data-formatter-cpp/main.cpp

i_am_cooler(int I1, int I2, float F1, float F2, char C1, char C2) :
     second_cool(I2,F2,C2),
     floating((F1 + F2)/2) {}
 };
 
 struct IUseCharStar
 {
   const char* pointer;
   IUseCharStar() : pointer("Hello world") {}
+
+        char const *member_func(int) { return ""; }
+        virtual void virt_member_func() {}
 };
 
 int main (int argc, const char * argv[])
 {
     
     int iAmInt = 1;
     const float& IAmFloat = float(2.45);
 
cool_pointer[2] = i_am_cool(0,-3.141592,'E');
     int int_array[] = {1,2,3,4,5};
     
     IUseCharStar iEncapsulateCharStar;
     
     char  strarr[32] = "Hello world!";
     char* strptr     = "Hello world!";
     
     i_am_cooler the_coolest_guy(1,2,3.14,6.28,'E','G');
-        
+    const char *IUseCharStar::*member_ptr = &IUseCharStar::pointer;
+    const char *(IUseCharStar::*member_func_ptr)(int) =
+        &IUseCharStar::member_func;
+    auto &ref_to_member_func_ptr = member_func_ptr;
+
+    void (IUseCharStar::*virt_member_func_ptr)() =
+        &IUseCharStar::virt_member_func;
+
     return 0; // Set break point at this line.
 }