How do I print the name of a variable created with create_tmp_var_raw

How do I print the name of a variable created with create_tmp_var_raw

[Thomas Koenig]

Hi,

I would like to know the name of a variable created with
create_tmp_var_raw, but it is not clear to my how to do it.

gimple_decl_printable_name sounded like a likely candidate,
but that just returns a null pointer.  Any combination of
IDENTIFIER_POINTER and DECL_NAME that I tried also led to
checking errors or segfaults.

More specifically,

diff --git a/gcc/fortran/trans.c b/gcc/fortran/trans.c
index f1c8f0ee17f..11043406840 100644
--- a/gcc/fortran/trans.c
+++ b/gcc/fortran/trans.c
@@ -96,7 +96,7 @@ gfc_create_var_np (tree type, const char *prefix)
    tree t;

    t = create_tmp_var_raw (type, prefix);
-
+  dprintf (2, "%s\n", IDENTIFIER_POINTER (DECL_NAME (t)));
    /* No warnings for anonymous variables.  */
    if (prefix == NULL)
      TREE_NO_WARNING (t) = 1;

which I thought should work according to the documentation I've
read resulted in a segfault.

Any pointers? Is there a magic incantation that I am missing?

Best regards

	Thomas

Re: How do I print the name of a variable created with create_tmp_var_raw

[Tobias Burnus]

Hi Thomas,

On 08.12.20 19:34, Thomas Koenig via Fortran wrote:
> I would like to know the name of a variable created with
> create_tmp_var_raw, but it is not clear to my how to do it.
> ...
>    t = create_tmp_var_raw (type, prefix);
> -
> +  dprintf (2, "%s\n", IDENTIFIER_POINTER (DECL_NAME (t)));

I think that's okay. However:

Do you have a prefix or not?

If there is no prefix, DECL_NAME (t) == NULL.

If there is a prefix, the name is create_tmp_var_name (prefix),
which is (on most systems)   "%s.%d", prefix, tmp_var_id_num++

Otherwise, the D.1234 you see in the dump is mostly the result of
"D.%u", DECL_UID (t).

I hope it helps,

Tobias

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Re: How do I print the name of a variable created with create_tmp_var_raw

[Thomas Koenig]

Hi Tobias,

> On 08.12.20 19:34, Thomas Koenig via Fortran wrote:
>> I would like to know the name of a variable created with
>> create_tmp_var_raw, but it is not clear to my how to do it.
>> ...
>>    t = create_tmp_var_raw (type, prefix);
>> -
>> +  dprintf (2, "%s\n", IDENTIFIER_POINTER (DECL_NAME (t)));
> 
> I think that's okay. However:
> 
> Do you have a prefix or not?
> 
> If there is no prefix, DECL_NAME (t) == NULL.
> 
> If there is a prefix, the name is create_tmp_var_name (prefix),
> which is (on most systems)   "%s.%d", prefix, tmp_var_id_num++
> 
> Otherwise, the D.1234 you see in the dump is mostly the result of
> "D.%u", DECL_UID (t).

Yes, this clears up things.  Thanks!

I am currently trying to figure out better ways of debugging
generated code (PR 90207) and one thing is to make intermediate
variables visible to the debugger, of course under control of
a special flag.  The dot is of course not a good choice beause
gdb will not print a variable called S.0, but maybe a @ will work.

Or, less amitious, sometimes it is hard to see by which path a
certain variable is generated. Being able to set a breakpoint
where a certain variable is being generated can help a lot.

Best regards

	Thomas