Re: [PATCH 1/1] PR100281 C++: Fix SImode pointer handling

[Andreas Krebbel <krebbel@linux.ibm.com>]

Ping

On 4/30/21 8:32 AM, Andreas Krebbel via Gcc-patches wrote:
> The problem appears to be triggered by two locations in the front-end
> where non-POINTER_SIZE pointers aren't handled right now.
> 
> 1. An assertion in strip_typedefs is triggered because the alignment
> of the types don't match. This in turn is caused by creating the new
> type with build_pointer_type instead of taking the type of the
> original pointer into account.
> 
> 2. An assertion in cp_convert_to_pointer is triggered which expects
> the target type to always have POINTER_SIZE.
> 
> Bootstrapped and regression tested on x86_64 and s390x.
> 
> Ok for mainline?
> 
> gcc/cp/ChangeLog:
> 
> 	PR c++/100281
> 	* cvt.c (cp_convert_to_pointer): Use the size of the target
> 	pointer type.
> 	* tree.c (cp_build_reference_type): Call
> 	cp_build_reference_type_for_mode with VOIDmode.
> 	(cp_build_reference_type_for_mode): Rename from
> 	cp_build_reference_type.  Add MODE argument and invoke
> 	build_reference_type_for_mode if MODE isn't VOIDmode.
> 	(strip_typedefs): Use build_pointer_type_for_mode and
> 	cp_build_reference_type_for_mode for pointers and references.
> 
> gcc/testsuite/ChangeLog:
> 
> 	PR c++/100281
> 	* g++.target/s390/pr100281-1.C: New test.
> 	* g++.target/s390/pr100281-2.C: New test.
> ---
>  gcc/cp/cvt.c                               |  2 +-
>  gcc/cp/tree.c                              | 28 +++++++++++++++++-----
>  gcc/testsuite/g++.target/s390/pr100281-1.C | 10 ++++++++
>  gcc/testsuite/g++.target/s390/pr100281-2.C |  9 +++++++
>  4 files changed, 42 insertions(+), 7 deletions(-)
>  create mode 100644 gcc/testsuite/g++.target/s390/pr100281-1.C
>  create mode 100644 gcc/testsuite/g++.target/s390/pr100281-2.C
> 
> diff --git a/gcc/cp/cvt.c b/gcc/cp/cvt.c
> index f1687e804d1..7fa6e8df52b 100644
> --- a/gcc/cp/cvt.c
> +++ b/gcc/cp/cvt.c
> @@ -232,7 +232,7 @@ cp_convert_to_pointer (tree type, tree expr, bool dofold,
>      {
>        if (TYPE_PRECISION (intype) == POINTER_SIZE)
>  	return build1 (CONVERT_EXPR, type, expr);
> -      expr = cp_convert (c_common_type_for_size (POINTER_SIZE, 0), expr,
> +      expr = cp_convert (c_common_type_for_size (TYPE_PRECISION (type), 0), expr,
>  			 complain);
>        /* Modes may be different but sizes should be the same.  There
>  	 is supposed to be some integral type that is the same width
> diff --git a/gcc/cp/tree.c b/gcc/cp/tree.c
> index a8bfd5fc053..3817b499e46 100644
> --- a/gcc/cp/tree.c
> +++ b/gcc/cp/tree.c
> @@ -1201,12 +1201,14 @@ vla_type_p (tree t)
>    return false;
>  }
>  
> -/* Return a reference type node referring to TO_TYPE.  If RVAL is
> +
> +/* Return a reference type node of MODE referring to TO_TYPE.  If MODE
> +   is VOIDmode the standard pointer mode will be picked.  If RVAL is
>     true, return an rvalue reference type, otherwise return an lvalue
>     reference type.  If a type node exists, reuse it, otherwise create
>     a new one.  */
>  tree
> -cp_build_reference_type (tree to_type, bool rval)
> +cp_build_reference_type_for_mode (tree to_type, machine_mode mode, bool rval)
>  {
>    tree lvalue_ref, t;
>  
> @@ -1219,7 +1221,11 @@ cp_build_reference_type (tree to_type, bool rval)
>        to_type = TREE_TYPE (to_type);
>      }
>  
> -  lvalue_ref = build_reference_type (to_type);
> +  if (mode == VOIDmode)
> +    lvalue_ref = build_reference_type (to_type);
> +  else
> +    lvalue_ref = build_reference_type_for_mode (to_type, mode, false);
> +
>    if (!rval)
>      return lvalue_ref;
>  
> @@ -1245,7 +1251,7 @@ cp_build_reference_type (tree to_type, bool rval)
>      SET_TYPE_STRUCTURAL_EQUALITY (t);
>    else if (TYPE_CANONICAL (to_type) != to_type)
>      TYPE_CANONICAL (t) 
> -      = cp_build_reference_type (TYPE_CANONICAL (to_type), rval);
> +      = cp_build_reference_type_for_mode (TYPE_CANONICAL (to_type), mode, rval);
>    else
>      TYPE_CANONICAL (t) = t;
>  
> @@ -1255,6 +1261,16 @@ cp_build_reference_type (tree to_type, bool rval)
>  
>  }
>  
> +/* Return a reference type node referring to TO_TYPE.  If RVAL is
> +   true, return an rvalue reference type, otherwise return an lvalue
> +   reference type.  If a type node exists, reuse it, otherwise create
> +   a new one.  */
> +tree
> +cp_build_reference_type (tree to_type, bool rval)
> +{
> +  return cp_build_reference_type_for_mode (to_type, VOIDmode, rval);
> +}
> +
>  /* Returns EXPR cast to rvalue reference type, like std::move.  */
>  
>  tree
> @@ -1556,11 +1572,11 @@ strip_typedefs (tree t, bool *remove_attributes, unsigned int flags)
>      {
>      case POINTER_TYPE:
>        type = strip_typedefs (TREE_TYPE (t), remove_attributes, flags);
> -      result = build_pointer_type (type);
> +      result = build_pointer_type_for_mode (type, TYPE_MODE (t), false);
>        break;
>      case REFERENCE_TYPE:
>        type = strip_typedefs (TREE_TYPE (t), remove_attributes, flags);
> -      result = cp_build_reference_type (type, TYPE_REF_IS_RVALUE (t));
> +      result = cp_build_reference_type_for_mode (type, TYPE_MODE (t), TYPE_REF_IS_RVALUE (t));
>        break;
>      case OFFSET_TYPE:
>        t0 = strip_typedefs (TYPE_OFFSET_BASETYPE (t), remove_attributes, flags);
> diff --git a/gcc/testsuite/g++.target/s390/pr100281-1.C b/gcc/testsuite/g++.target/s390/pr100281-1.C
> new file mode 100644
> index 00000000000..b82e27b64e9
> --- /dev/null
> +++ b/gcc/testsuite/g++.target/s390/pr100281-1.C
> @@ -0,0 +1,10 @@
> +// PR C++/100281
> +// { dg-do compile }
> +
> +typedef void * __attribute__((mode (SI))) __ptr32_t;
> +
> +void foo () {
> +  unsigned int b = 100;
> +  __ptr32_t a;
> +  a = b; /* { dg-error "invalid conversion from 'unsigned int' to '__ptr32_t'.*" } */
> +}
> diff --git a/gcc/testsuite/g++.target/s390/pr100281-2.C b/gcc/testsuite/g++.target/s390/pr100281-2.C
> new file mode 100644
> index 00000000000..58552becd7c
> --- /dev/null
> +++ b/gcc/testsuite/g++.target/s390/pr100281-2.C
> @@ -0,0 +1,9 @@
> +// PR C++/100281
> +// { dg-do compile }
> +
> +typedef int & __attribute__((mode (SI))) __ref32_t;
> +
> +void foo () {
> +  unsigned int b = 100;
> +  __ref32_t a = b; /* { dg-error "cannot bind non-const lvalue reference of type '__ref32_t'.*" } */
> +}
>