Question on typedefs of anonymous structs in G++

Question on typedefs of anonymous structs in G++

[Paul Hilfinger]

Using g++ 4.1 on Linux (at least), I observe that a type such as

      typedef struct {
          ...
      } Foo;

produces no trace of debugging information about Foo.  Serves one
right for writing a C-style definition of Foo in a C++ program, to be
sure, but G++ used to include Foo in the debugging data.  Does anyone
here happen to know the story behind the change?  Thanks.

Paul Hilfinger

Re: Question on typedefs of anonymous structs in G++

[Daniel Jacobowitz]

On Wed, May 07, 2008 at 05:00:45AM -0400, Paul Hilfinger wrote:
> produces no trace of debugging information about Foo.  Serves one
> right for writing a C-style definition of Foo in a C++ program, to be
> sure, but G++ used to include Foo in the debugging data.  Does anyone
> here happen to know the story behind the change?  Thanks.

It is presumably just a bug (if the type is used somewhere); I suggest
verifying it on HEAD and putting it in gcc's bugzilla.

-- 
Daniel Jacobowitz
CodeSourcery

Re: Question on typedefs of anonymous structs in G++

[Michael Snyder]

On Wed, 2008-05-07 at 05:00 -0400, Paul Hilfinger wrote:
> Using g++ 4.1 on Linux (at least), I observe that a type such as
> 
>       typedef struct {
>           ...
>       } Foo;
> 
> produces no trace of debugging information about Foo.  Serves one
> right for writing a C-style definition of Foo in a C++ program, to be
> sure, but G++ used to include Foo in the debugging data.  Does anyone
> here happen to know the story behind the change?  Thanks.

Did you actually declare an object of the type?
And use the object, so that it couldn't be optimized away?

Without an instance of a type, G++ will likely optimize the 
debug info for the type away.