Re: [PATCH] Fix PR 101515 (ICE in pp_cxx_unqualified_id, at cp/cxx-pretty-print.c:128)

[Jason Merrill <jason@redhat.com>]

On 2/8/22 15:11, Qing Zhao wrote:
> Hi,
> 
> This is the patch to fix PR101515 (ICE in pp_cxx_unqualified_id, at  cp/cxx-pretty-print.c:128)
> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101515
> 
> It's possible that the TYPE_NAME of a record_type is NULL, therefore when
> printing the TYPE_NAME, we should check and handle this special case.
> 
> Please see the comment of pr101515 for more details.
> 
> The fix is very simple, just check and special handle cases when TYPE_NAME is NULL.
> 
> Bootstrapped and regression tested on both x86 and aarch64, no issues.
> 
> Okay for commit?
> 
> Thanks.
> 
> Qing
> 
> =====================================
> 
>  From f37ee8d21b80cb77d8108cb97a487c84c530545b Mon Sep 17 00:00:00 2001
> From: Qing Zhao <qing.zhao@oracle.com>
> Date: Tue, 8 Feb 2022 16:10:37 +0000
> Subject: [PATCH] Fix PR 101515 ICE in pp_cxx_unqualified_id, at
>   cp/cxx-pretty-print.c:128.
> 
> It's possible that the TYPE_NAME of a record_type is NULL, therefore when
> printing the TYPE_NAME, we should check and handle this special case.
> 
> gcc/cp/ChangeLog:
> 
> 	* cxx-pretty-print.cc (pp_cxx_unqualified_id): Check and handle
> 	the case when TYPE_NAME is NULL.
> 
> gcc/testsuite/ChangeLog:
> 
> 	* g++.dg/pr101515.C: New test.
> ---
>   gcc/cp/cxx-pretty-print.cc      |  5 ++++-
>   gcc/testsuite/g++.dg/pr101515.C | 25 +++++++++++++++++++++++++
>   2 files changed, 29 insertions(+), 1 deletion(-)
>   create mode 100644 gcc/testsuite/g++.dg/pr101515.C
> 
> diff --git a/gcc/cp/cxx-pretty-print.cc b/gcc/cp/cxx-pretty-print.cc
> index 4f9a090e520d..744ed0add5ba 100644
> --- a/gcc/cp/cxx-pretty-print.cc
> +++ b/gcc/cp/cxx-pretty-print.cc
> @@ -171,7 +171,10 @@ pp_cxx_unqualified_id (cxx_pretty_printer *pp, tree t)
>       case ENUMERAL_TYPE:
>       case TYPENAME_TYPE:
>       case UNBOUND_CLASS_TEMPLATE:
> -      pp_cxx_unqualified_id (pp, TYPE_NAME (t));
> +      if (TYPE_NAME (t))
> +	pp_cxx_unqualified_id (pp, TYPE_NAME (t));
> +      else
> +	pp_string (pp, "<unnamed type>");

Hmm, but it's not an unnamed class, it's a pointer to member function 
type, and it would be better to avoid dumping compiler internal 
representations like the __pfn field name.

I think the real problem comes sooner, when c_fold_indirect_ref_for_warn 
turns a MEM_REF with RECORD_TYPE into a COMPONENT_REF with POINTER_TYPE.

>         if (tree ti = TYPE_TEMPLATE_INFO_MAYBE_ALIAS (t))
>   	if (PRIMARY_TEMPLATE_P (TI_TEMPLATE (ti)))
>   	  {
> diff --git a/gcc/testsuite/g++.dg/pr101515.C b/gcc/testsuite/g++.dg/pr101515.C
> new file mode 100644
> index 000000000000..898c7e003c22
> --- /dev/null
> +++ b/gcc/testsuite/g++.dg/pr101515.C
> @@ -0,0 +1,25 @@
> +/* PR101515 -  ICE in pp_cxx_unqualified_id, at cp/cxx-pretty-print.c:128
> +   { dg-do compile }
> +   { dg-options "-Wuninitialized -O1" } */
> +
> +struct S
> +{
> +  int j;
> +};
> +struct T : public S
> +{
> +  virtual void h () {}
> +};
> +struct ptrmemfunc
> +{
> +  void (*ptr) ();
> +};
> +typedef void (S::*sp)();
> +int main ()
> +{
> +  T t;
> +  sp x;
> +  ptrmemfunc *xp = (ptrmemfunc *) &x;
> +  if (xp->ptr != ((void (*)())(sizeof(void *))))  /* { dg-warning "is used uninitialized" } */
> +    return 1;
> +}