Re: [PATCH v2] c++: ICE with computed gotos [PR115469]

[Jason Merrill <jason@redhat.com>]

On 7/1/24 5:09 PM, Marek Polacek wrote:
> On Mon, Jul 01, 2024 at 02:44:56PM -0400, Jason Merrill wrote:
>> On 6/26/24 6:04 PM, Marek Polacek wrote:
>>> Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk?
>>>
>>> -- >8 --
>>> This is a low-prio crash on invalid code where we ICE on a VAR_DECL
>>> with erroneous type.  I thought I'd try to avoid putting such decls
>>> into ->names and ->names_in_scope but that sounds riskier than the
>>> following cleanup.
>>>
>>> 	PR c++/115469
>>>
>>> gcc/cp/ChangeLog:
>>>
>>> 	* decl.cc (decl_with_nontrivial_dtor_p): New.
>>
>> This name doesn't suggest non-static variable to me.  Maybe
>> automatic_var_with...?
> 
> Sounds good.
> 
>> While we're at it, we should also avoid complaining about thread-local by
>> checking decl_storage_duration == dk_auto, since [stmt.dcl]/2 is
>> specifically about automatic.
> 
> Done here.
> 
> Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk?
> 
> -- >8 --
> This is a low-prio crash on invalid code where we ICE on a VAR_DECL
> with erroneous type.  I thought I'd try to avoid putting such decls
> into ->names and ->names_in_scope but that sounds riskier than the
> following cleanup.
> 
> 	PR c++/115469
> 
> gcc/cp/ChangeLog:
> 
> 	* decl.cc (automatic_var_with_nontrivial_dtor_p): New.
> 	(poplevel_named_label_1): Use it.
> 	(check_goto_1): Likewise.
> 
> gcc/testsuite/ChangeLog:
> 
> 	* g++.dg/ext/label17.C: New test.
> ---
>   gcc/cp/decl.cc                     | 21 +++++++++++++++++----
>   gcc/testsuite/g++.dg/ext/label17.C | 18 ++++++++++++++++++
>   2 files changed, 35 insertions(+), 4 deletions(-)
>   create mode 100644 gcc/testsuite/g++.dg/ext/label17.C
> 
> diff --git a/gcc/cp/decl.cc b/gcc/cp/decl.cc
> index 03deb1493a4..d439b04bfa7 100644
> --- a/gcc/cp/decl.cc
> +++ b/gcc/cp/decl.cc
> @@ -514,6 +514,21 @@ level_for_consteval_if (cp_binding_level *b)
>   	  && IF_STMT_CONSTEVAL_P (b->this_entity));
>   }
>   
> +/* True if T is a non-static VAR_DECL that has a non-trivial destructor.
> +   See [stmt.dcl]/2.  */
> +
> +static bool
> +automatic_var_with_nontrivial_dtor_p (const_tree t)
> +{
> +  if (error_operand_p (t))
> +    return false;
> +
> +  return (VAR_P (t)
> +	  && !TREE_STATIC (t)

Checking TREE_STATIC is redundant with checking decl_storage_duration. 
OK without the above line.

> +	  && decl_storage_duration (CONST_CAST_TREE (t)) == dk_auto
> +	  && TYPE_HAS_NONTRIVIAL_DESTRUCTOR (TREE_TYPE (t)));
> +}
> +
>   /* Update data for defined and undefined labels when leaving a scope.  */
>   
>   int
> @@ -575,8 +590,7 @@ poplevel_named_label_1 (named_label_entry **slot, cp_binding_level *bl)
>   		if (bl->kind == sk_catch)
>   		  vec_safe_push (cg, get_identifier ("catch"));
>   		for (tree d = use->names_in_scope; d; d = DECL_CHAIN (d))
> -		  if (TREE_CODE (d) == VAR_DECL && !TREE_STATIC (d)
> -		      && TYPE_HAS_NONTRIVIAL_DESTRUCTOR (TREE_TYPE (d)))
> +		  if (automatic_var_with_nontrivial_dtor_p (d))
>   		    vec_safe_push (cg, d);
>   	      }
>   
> @@ -4003,8 +4017,7 @@ check_goto_1 (named_label_entry *ent, bool computed)
>   	  tree end = b == level ? names : NULL_TREE;
>   	  for (tree d = b->names; d != end; d = DECL_CHAIN (d))
>   	    {
> -	      if (TREE_CODE (d) == VAR_DECL && !TREE_STATIC (d)
> -		  && TYPE_HAS_NONTRIVIAL_DESTRUCTOR (TREE_TYPE (d)))
> +	      if (automatic_var_with_nontrivial_dtor_p (d))
>   		{
>   		  if (!identified)
>   		    {
> diff --git a/gcc/testsuite/g++.dg/ext/label17.C b/gcc/testsuite/g++.dg/ext/label17.C
> new file mode 100644
> index 00000000000..076ef1f798e
> --- /dev/null
> +++ b/gcc/testsuite/g++.dg/ext/label17.C
> @@ -0,0 +1,18 @@
> +// PR c++/115469
> +// { dg-do compile { target indirect_jumps } }
> +// { dg-options "" }
> +
> +void
> +fn1 ()
> +{
> +  b = &&c;    // { dg-error "not declared|not defined" }
> +  goto *0;
> +}
> +
> +void
> +fn2 ()
> +{
> +c:
> +  b = &&c;  // { dg-error "not declared" }
> +  goto *0;
> +}
> 
> base-commit: c847dcf94499da62e5a28921b404e6e561645d99