Clarifying the documentation for variable formatting wrt to qualifiers and adding a test that demonstrates this

[shafik]

Summary

When looking up user specified formatters qualifiers are removed from types before matching, I have added a clarifying example to the document and added an example to a relevant test to demonstrate this behavior.

[teemperor]

LGTM, thanks! FWIW, there are actually a lot more 'qualifiers' supported in Clang that are ignored by the formatters (restrict, Obj-C garbage collector descriptions, custom address spaces, etc.). Most of them are not even modelled in DWARF and users rarely encounter them, so I think const/volatile should cover all reasonable workflows.

lldb/test/API/functionalities/data-formatter/data-formatter-advanced/TestDataFormatterAdv.py

247

There are test methods for frame var:
self.expect_var_path("constVolatileInt", value="0x0000002c")

[shafik]

Updating test to use frame var test.

lldb/docs/use/variable.rst

 ::
 
    (lldb) frame variable -T
    (A) a = 0x00000001
    (B) b = 2
    (C) c = {0x03 0x00 0x00 0x00}
    (D) d = 4
 
+Note, that qualifiers such as const and volatile will be stripped when matching types for example:
+
+::
+
+   (lldb) frame var x y z
+   (int) x = 1
+   (const int) y = 2
+   (volatile int) z = 4
+   (lldb) type format add -f hex int
+   (lldb) frame var x y z
+   (int) x = 0x00000001
+   (const int) y = 0x00000002
+   (volatile int) z = 0x00000004
+
 Two additional options that you will want to look at are --skip-pointers (-p)
 and --skip-references (-r). These two options prevent LLDB from applying a
 format for type T to values of type T* and T& respectively.
 
 ::
 
    (lldb) type format add -f float32[] int
    (lldb) frame variable pointer *pointer -T

lldb/test/API/functionalities/data-formatter/data-formatter-advanced/TestDataFormatterAdv.py

def test_with_run_command(self):
         self.runCmd("type summary add --summary-string \"x=${var.x}\" Simple")
 
         self.expect("frame variable a_simple_object", matching=False,
                     substrs=['x=3'])
 
         self.expect("frame variable a_simple_object", matching=True,
                     substrs=['x=0x00000003'])
 
+        self.expect_var_path("constInt", value='0x0000002a') 
+
+        self.expect_var_path("volatileInt", value='0x0000002b')
+
+        self.expect_var_path("constVolatileInt", value='0x0000002c')
+
         # check that we can correctly cap the number of children shown
         self.runCmd("settings set target.max-children-count 5")
 
         self.expect('frame variable a_long_guy', matching=True,
                     substrs=['a_1',
                              'b_1',
                              'c_1',
                              'd_1',

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

struct VeryLong
     int y_2;
     int z_2;
 };
 
 int main (int argc, const char * argv[])
 {
     
     int iAmInt = 9;
+    const int constInt = 42;
+    volatile int volatileInt = 43;
+    const volatile int constVolatileInt = 44;
     
     i_am_cool cool_boy(1,0.5,3);
     i_am_cooler cooler_boy(1,2,0.1,0.2,'A','B');
     
   i_am_cool *cool_pointer = new i_am_cool(3,-3.141592,'E');
     
     i_am_cool cool_array[5];