[v3] bpf: add preserve_field_info builtin

  >> I'm not sure whether this behavior is a known limitation or an
>> oversight. In my opinion it makes more sense to error at compile time,
>> becuase even after the loader patches the return value it still will
>> not be correct for these cases.
>>
>> So for now I've set these cases to error out, but it would be just as
>> simple to mimic the LLVM behavior. WDYT?
> 
> I would say it makes more sense to error out than to return invalid
> data.
> 
> However, the divergence wrt LLVM is a concern.  What about keeping this
> behavior in the GCC backend and simultaneously raise the issue in
> bpf@vger?  If it was a design oversight and the change doesn't impact
> kernel sources, they may be willing to change it.
> 

OK, I will raise the question there.

>> [...]
>> +@deftypefn {Built-in Function} unsigned int __builtin_preserve_field_info (@var{expr}, unsigned int @var{kind})
>> +BPF Compile Once-Run Everywhere (CO-RE) support. This builtin is used to
>> +extract information to aid in struct/union relocations.  @var{expr} is
>> +an access to a field of a struct or union. Depending on @var{kind}, different
>> +information is returned to the program. A CO-RE relocation for the access in
>> +@var{expr} with kind @var{kind} is recorded if @code{-mco-re} is in effect.
>> +
>> +The following values are supported for @var{kind}:
>> +@table @var
>> +@item FIELD_BYTE_OFFSET = 0
>> +The returned value is the offset, in bytes, of the field from the
>> +beginning of the containing structure.
> 
> What about bit fields?  Is this the byte offset of the containing word?

Yes.

> 
>> +@item FIELD_BYTE_SIZE = 1
>> +The returned value is the size, in bytes, of the field.
> 
> For bit fields,  is this the size of the containing word?

Right again. I have updated the docs for these two in v3.

> 
>> +@item FIELD_EXISTENCE = 2
>> +The returned value is 1 if the field exists, 0 otherwise. Always 1 at
>> +compile time.
>> +
>> +@item FIELD_SIGNEDNESS = 3
>> +The returned value is 1 if the field is signed, 0 otherwise.
>> +
>> +@item FIELD_LSHIFT_U64 = 4
>> +@itemx FIELD_RSHIFT_U64 = 5
>> +Suppose the field were loaded into a value of FIELD_BYTE_SIZE bytes
>> +and then zero or sign-extended to a 64-bit value. The returned value
>> +is the number of bits of left or right shifting respectively that
>> +would be needed to recover the original value of the field.
> 
> What are the semantics for bit fields?

The semantics for bit fields are the same. These two are primarily
useful for bit fields - a common case in eBPF programs is to read
some field of a struct through a pointer. If it's a kernel struct
that may change between versions and you are reading a bit field,
you would use this builtin to get the eBPF loader to patch the
appropriate steps to extract the field.

So the process to read a bit field is the following:

  1. read FIELD_BYTE_SIZE bytes and zero-extend the value of the
     read into a u64
  2. left shift the result FIELD_LSHIFT_U64 bits
  3. if FIELD_SIGNEDNESS
       then arithmetic right-shift by FIELD_RSHIFT_U64 bits
     otherwise
       logical right-shift by FIELD_RSHIFT_U64 bits

Where all these FIELD_* values might change between kernels and
need patching by the eBPF loader.

I struggled a bit trying to find the best wording to describe this
in the docs, and settled on adding some example code since I think
that is the most clear.

Please take a look at the updated version and let me know if you
have any suggestions, I'm happy to hear them.

Thanks

---

[Changes from v2: update documentation in extend.texi]

Add BPF __builtin_preserve_field_info. This builtin is used to extract
information to facilitate struct and union relocations performed by the
BPF loader, especially for bitfields.

The builtin has the following signature:

  unsigned int __builtin_preserve_field_info (EXPR, unsigned int KIND);

Where EXPR is an expression accessing a field of a struct or union.
Depending on KIND, different information is returned to the program. The
supported values for KIND are as follows:

  enum {
    FIELD_BYTE_OFFSET = 0,
    FIELD_BYTE_SIZE,
    FIELD_EXISTENCE,
    FIELD_SIGNEDNESS,
    FIELD_LSHIFT_U64,
    FIELD_RSHIFT_U64
  };

If -mco-re is in effect (explicitly or implicitly specified), a CO-RE
relocation is added for the access in EXPR recording the relevant
information according to KIND.

gcc/

	* config/bpf/bpf.cc: Support __builtin_preserve_field_info.
	(enum bpf_builtins): Add new builtin.
	(bpf_init_builtins): Likewise.
	(bpf_core_field_info): New function.
	(bpf_expand_builtin): Accomodate new builtin. Refactor adding new
	relocation to...
	(maybe_make_core_relo): ... here. New function.
	(bpf_resolve_overloaded_builtin): Accomodate new builtin.
	(bpf_core_newdecl): Likewise.
	(bpf_core_walk): Likewise.
	(bpf_core_is_maybe_aggregate_access): Improve logic.
	(struct core_walk_data): New.
	* config/bpf/coreout.cc (bpf_core_reloc_add): Allow adding different
	relocation kinds.
	* config/bpf/coreout.h: Analogous change.
	* doc/extend.texi: Document BPF __builtin_preserve_field_info.

gcc/testsuite/

	* gcc.target/bpf/core-builtin-fieldinfo-errors-1.c: New test.
	* gcc.target/bpf/core-builtin-fieldinfo-errors-2.c: New test.
	* gcc.target/bpf/core-builtin-fieldinfo-existence-1.c: New test.
	* gcc.target/bpf/core-builtin-fieldinfo-lshift-1-be.c: New test.
	* gcc.target/bpf/core-builtin-fieldinfo-lshift-1-le.c: New test.
	* gcc.target/bpf/core-builtin-fieldinfo-lshift-2.c: New test.
	* gcc.target/bpf/core-builtin-fieldinfo-offset-1.c: New test.
	* gcc.target/bpf/core-builtin-fieldinfo-rshift-1.c: New test.
	* gcc.target/bpf/core-builtin-fieldinfo-rshift-2.c: New test.
	* gcc.target/bpf/core-builtin-fieldinfo-sign-1.c: New test.
	* gcc.target/bpf/core-builtin-fieldinfo-sign-2.c: New test.
	* gcc.target/bpf/core-builtin-fieldinfo-size-1.c: New test.
---
 gcc/config/bpf/bpf.cc                         | 402 ++++++++++++++----
 gcc/config/bpf/coreout.cc                     |   5 +-
 gcc/config/bpf/coreout.h                      |   2 +-
 gcc/doc/extend.texi                           |  77 ++++
 .../bpf/core-builtin-fieldinfo-errors-1.c     |  23 +
 .../bpf/core-builtin-fieldinfo-errors-2.c     |  23 +
 .../bpf/core-builtin-fieldinfo-existence-1.c  |  34 ++
 .../bpf/core-builtin-fieldinfo-lshift-1-be.c  |  37 ++
 .../bpf/core-builtin-fieldinfo-lshift-1-le.c  |  37 ++
 .../bpf/core-builtin-fieldinfo-lshift-2.c     |  37 ++
 .../bpf/core-builtin-fieldinfo-offset-1.c     |  56 +++
 .../bpf/core-builtin-fieldinfo-rshift-1.c     |  36 ++
 .../bpf/core-builtin-fieldinfo-rshift-2.c     |  35 ++
 .../bpf/core-builtin-fieldinfo-sign-1.c       |  33 ++
 .../bpf/core-builtin-fieldinfo-sign-2.c       |  45 ++
 .../bpf/core-builtin-fieldinfo-size-1.c       |  43 ++
 16 files changed, 850 insertions(+), 75 deletions(-)
 create mode 100644 gcc/testsuite/gcc.target/bpf/core-builtin-fieldinfo-errors-1.c
 create mode 100644 gcc/testsuite/gcc.target/bpf/core-builtin-fieldinfo-errors-2.c
 create mode 100644 gcc/testsuite/gcc.target/bpf/core-builtin-fieldinfo-existence-1.c
 create mode 100644 gcc/testsuite/gcc.target/bpf/core-builtin-fieldinfo-lshift-1-be.c
 create mode 100644 gcc/testsuite/gcc.target/bpf/core-builtin-fieldinfo-lshift-1-le.c
 create mode 100644 gcc/testsuite/gcc.target/bpf/core-builtin-fieldinfo-lshift-2.c
 create mode 100644 gcc/testsuite/gcc.target/bpf/core-builtin-fieldinfo-offset-1.c
 create mode 100644 gcc/testsuite/gcc.target/bpf/core-builtin-fieldinfo-rshift-1.c
 create mode 100644 gcc/testsuite/gcc.target/bpf/core-builtin-fieldinfo-rshift-2.c
 create mode 100644 gcc/testsuite/gcc.target/bpf/core-builtin-fieldinfo-sign-1.c
 create mode 100644 gcc/testsuite/gcc.target/bpf/core-builtin-fieldinfo-sign-2.c
 create mode 100644 gcc/testsuite/gcc.target/bpf/core-builtin-fieldinfo-size-1.c
  

Hi David.

Thanks for the updates.
OK for master.

>>> I'm not sure whether this behavior is a known limitation or an
>>> oversight. In my opinion it makes more sense to error at compile time,
>>> becuase even after the loader patches the return value it still will
>>> not be correct for these cases.
>>>
>>> So for now I've set these cases to error out, but it would be just as
>>> simple to mimic the LLVM behavior. WDYT?
>> 
>> I would say it makes more sense to error out than to return invalid
>> data.
>> 
>> However, the divergence wrt LLVM is a concern.  What about keeping this
>> behavior in the GCC backend and simultaneously raise the issue in
>> bpf@vger?  If it was a design oversight and the change doesn't impact
>> kernel sources, they may be willing to change it.
>> 
>
> OK, I will raise the question there.
>
>>> [...]
>>> +@deftypefn {Built-in Function} unsigned int
>>> __builtin_preserve_field_info (@var{expr}, unsigned int @var{kind})
>>> +BPF Compile Once-Run Everywhere (CO-RE) support. This builtin is used to
>>> +extract information to aid in struct/union relocations.  @var{expr} is
>>> +an access to a field of a struct or union. Depending on @var{kind}, different
>>> +information is returned to the program. A CO-RE relocation for the access in
>>> +@var{expr} with kind @var{kind} is recorded if @code{-mco-re} is in effect.
>>> +
>>> +The following values are supported for @var{kind}:
>>> +@table @var
>>> +@item FIELD_BYTE_OFFSET = 0
>>> +The returned value is the offset, in bytes, of the field from the
>>> +beginning of the containing structure.
>> 
>> What about bit fields?  Is this the byte offset of the containing word?
>
> Yes.
>
>> 
>>> +@item FIELD_BYTE_SIZE = 1
>>> +The returned value is the size, in bytes, of the field.
>> 
>> For bit fields,  is this the size of the containing word?
>
> Right again. I have updated the docs for these two in v3.
>
>> 
>>> +@item FIELD_EXISTENCE = 2
>>> +The returned value is 1 if the field exists, 0 otherwise. Always 1 at
>>> +compile time.
>>> +
>>> +@item FIELD_SIGNEDNESS = 3
>>> +The returned value is 1 if the field is signed, 0 otherwise.
>>> +
>>> +@item FIELD_LSHIFT_U64 = 4
>>> +@itemx FIELD_RSHIFT_U64 = 5
>>> +Suppose the field were loaded into a value of FIELD_BYTE_SIZE bytes
>>> +and then zero or sign-extended to a 64-bit value. The returned value
>>> +is the number of bits of left or right shifting respectively that
>>> +would be needed to recover the original value of the field.
>> 
>> What are the semantics for bit fields?
>
> The semantics for bit fields are the same. These two are primarily
> useful for bit fields - a common case in eBPF programs is to read
> some field of a struct through a pointer. If it's a kernel struct
> that may change between versions and you are reading a bit field,
> you would use this builtin to get the eBPF loader to patch the
> appropriate steps to extract the field.
>
> So the process to read a bit field is the following:
>
>   1. read FIELD_BYTE_SIZE bytes and zero-extend the value of the
>      read into a u64
>   2. left shift the result FIELD_LSHIFT_U64 bits
>   3. if FIELD_SIGNEDNESS
>        then arithmetic right-shift by FIELD_RSHIFT_U64 bits
>      otherwise
>        logical right-shift by FIELD_RSHIFT_U64 bits
>
> Where all these FIELD_* values might change between kernels and
> need patching by the eBPF loader.
>
> I struggled a bit trying to find the best wording to describe this
> in the docs, and settled on adding some example code since I think
> that is the most clear.
>
> Please take a look at the updated version and let me know if you
> have any suggestions, I'm happy to hear them.
>
> Thanks
>
> ---
>
> [Changes from v2: update documentation in extend.texi]
>
> Add BPF __builtin_preserve_field_info. This builtin is used to extract
> information to facilitate struct and union relocations performed by the
> BPF loader, especially for bitfields.
>
> The builtin has the following signature:
>
>   unsigned int __builtin_preserve_field_info (EXPR, unsigned int KIND);
>
> Where EXPR is an expression accessing a field of a struct or union.
> Depending on KIND, different information is returned to the program. The
> supported values for KIND are as follows:
>
>   enum {
>     FIELD_BYTE_OFFSET = 0,
>     FIELD_BYTE_SIZE,
>     FIELD_EXISTENCE,
>     FIELD_SIGNEDNESS,
>     FIELD_LSHIFT_U64,
>     FIELD_RSHIFT_U64
>   };
>
> If -mco-re is in effect (explicitly or implicitly specified), a CO-RE
> relocation is added for the access in EXPR recording the relevant
> information according to KIND.
>
> gcc/
>
> 	* config/bpf/bpf.cc: Support __builtin_preserve_field_info.
> 	(enum bpf_builtins): Add new builtin.
> 	(bpf_init_builtins): Likewise.
> 	(bpf_core_field_info): New function.
> 	(bpf_expand_builtin): Accomodate new builtin. Refactor adding new
> 	relocation to...
> 	(maybe_make_core_relo): ... here. New function.
> 	(bpf_resolve_overloaded_builtin): Accomodate new builtin.
> 	(bpf_core_newdecl): Likewise.
> 	(bpf_core_walk): Likewise.
> 	(bpf_core_is_maybe_aggregate_access): Improve logic.
> 	(struct core_walk_data): New.
> 	* config/bpf/coreout.cc (bpf_core_reloc_add): Allow adding different
> 	relocation kinds.
> 	* config/bpf/coreout.h: Analogous change.
> 	* doc/extend.texi: Document BPF __builtin_preserve_field_info.
>
> gcc/testsuite/
>
> 	* gcc.target/bpf/core-builtin-fieldinfo-errors-1.c: New test.
> 	* gcc.target/bpf/core-builtin-fieldinfo-errors-2.c: New test.
> 	* gcc.target/bpf/core-builtin-fieldinfo-existence-1.c: New test.
> 	* gcc.target/bpf/core-builtin-fieldinfo-lshift-1-be.c: New test.
> 	* gcc.target/bpf/core-builtin-fieldinfo-lshift-1-le.c: New test.
> 	* gcc.target/bpf/core-builtin-fieldinfo-lshift-2.c: New test.
> 	* gcc.target/bpf/core-builtin-fieldinfo-offset-1.c: New test.
> 	* gcc.target/bpf/core-builtin-fieldinfo-rshift-1.c: New test.
> 	* gcc.target/bpf/core-builtin-fieldinfo-rshift-2.c: New test.
> 	* gcc.target/bpf/core-builtin-fieldinfo-sign-1.c: New test.
> 	* gcc.target/bpf/core-builtin-fieldinfo-sign-2.c: New test.
> 	* gcc.target/bpf/core-builtin-fieldinfo-size-1.c: New test.
> ---
>  gcc/config/bpf/bpf.cc                         | 402 ++++++++++++++----
>  gcc/config/bpf/coreout.cc                     |   5 +-
>  gcc/config/bpf/coreout.h                      |   2 +-
>  gcc/doc/extend.texi                           |  77 ++++
>  .../bpf/core-builtin-fieldinfo-errors-1.c     |  23 +
>  .../bpf/core-builtin-fieldinfo-errors-2.c     |  23 +
>  .../bpf/core-builtin-fieldinfo-existence-1.c  |  34 ++
>  .../bpf/core-builtin-fieldinfo-lshift-1-be.c  |  37 ++
>  .../bpf/core-builtin-fieldinfo-lshift-1-le.c  |  37 ++
>  .../bpf/core-builtin-fieldinfo-lshift-2.c     |  37 ++
>  .../bpf/core-builtin-fieldinfo-offset-1.c     |  56 +++
>  .../bpf/core-builtin-fieldinfo-rshift-1.c     |  36 ++
>  .../bpf/core-builtin-fieldinfo-rshift-2.c     |  35 ++
>  .../bpf/core-builtin-fieldinfo-sign-1.c       |  33 ++
>  .../bpf/core-builtin-fieldinfo-sign-2.c       |  45 ++
>  .../bpf/core-builtin-fieldinfo-size-1.c       |  43 ++
>  16 files changed, 850 insertions(+), 75 deletions(-)
>  create mode 100644 gcc/testsuite/gcc.target/bpf/core-builtin-fieldinfo-errors-1.c
>  create mode 100644 gcc/testsuite/gcc.target/bpf/core-builtin-fieldinfo-errors-2.c
>  create mode 100644 gcc/testsuite/gcc.target/bpf/core-builtin-fieldinfo-existence-1.c
>  create mode 100644 gcc/testsuite/gcc.target/bpf/core-builtin-fieldinfo-lshift-1-be.c
>  create mode 100644 gcc/testsuite/gcc.target/bpf/core-builtin-fieldinfo-lshift-1-le.c
>  create mode 100644 gcc/testsuite/gcc.target/bpf/core-builtin-fieldinfo-lshift-2.c
>  create mode 100644 gcc/testsuite/gcc.target/bpf/core-builtin-fieldinfo-offset-1.c
>  create mode 100644 gcc/testsuite/gcc.target/bpf/core-builtin-fieldinfo-rshift-1.c
>  create mode 100644 gcc/testsuite/gcc.target/bpf/core-builtin-fieldinfo-rshift-2.c
>  create mode 100644 gcc/testsuite/gcc.target/bpf/core-builtin-fieldinfo-sign-1.c
>  create mode 100644 gcc/testsuite/gcc.target/bpf/core-builtin-fieldinfo-sign-2.c
>  create mode 100644 gcc/testsuite/gcc.target/bpf/core-builtin-fieldinfo-size-1.c
>
> diff --git a/gcc/config/bpf/bpf.cc b/gcc/config/bpf/bpf.cc
> index 51055651707..ea8ca64d1d6 100644
> --- a/gcc/config/bpf/bpf.cc
> +++ b/gcc/config/bpf/bpf.cc
> @@ -184,13 +184,13 @@ enum bpf_builtins
>  
>    /* Compile Once - Run Everywhere (CO-RE) support.  */
>    BPF_BUILTIN_PRESERVE_ACCESS_INDEX,
> +  BPF_BUILTIN_PRESERVE_FIELD_INFO,
>  
>    BPF_BUILTIN_MAX,
>  };
>  
>  static GTY (()) tree bpf_builtins[(int) BPF_BUILTIN_MAX];
>  
> -
>  void bpf_register_coreattr_pass (void);
>  
>  /* Initialize the per-function machine status.  */
> @@ -966,6 +966,9 @@ bpf_init_builtins (void)
>    def_builtin ("__builtin_preserve_access_index",
>  	       BPF_BUILTIN_PRESERVE_ACCESS_INDEX,
>  	       build_function_type_list (ptr_type_node, ptr_type_node, 0));
> +  def_builtin ("__builtin_preserve_field_info",
> +	       BPF_BUILTIN_PRESERVE_FIELD_INFO,
> +	       build_function_type_list (unsigned_type_node, ptr_type_node, unsigned_type_node, 0));
>  }
>  
>  #undef TARGET_INIT_BUILTINS
> @@ -975,6 +978,199 @@ static tree bpf_core_compute (tree, vec<unsigned int> *);
>  static int bpf_core_get_index (const tree);
>  static bool is_attr_preserve_access (tree);
>  
> +/* BPF Compile Once - Run Everywhere (CO-RE) support. Construct a CO-RE
> +   relocation record for EXPR of kind KIND to be emitted in the .BTF.ext
> +   section. Does nothing if we are not targetting BPF CO-RE, or if the
> +   constructed relocation would be a no-op.  */
> +
> +static void
> +maybe_make_core_relo (tree expr, enum btf_core_reloc_kind kind)
> +{
> +  /* If we are not targetting BPF CO-RE, do not make a relocation. We
> +     might not be generating any debug info at all.  */
> +  if (!TARGET_BPF_CORE)
> +    return;
> +
> +  auto_vec<unsigned int, 16> accessors;
> +  tree container = bpf_core_compute (expr, &accessors);
> +
> +  /* Any valid use of the builtin must have at least one access. Otherwise,
> +     there is nothing to record and nothing to do. This is primarily a
> +     guard against optimizations leading to unexpected expressions in the
> +     argument of the builtin. For example, if the builtin is used to read
> +     a field of a structure which can be statically determined to hold a
> +     constant value, the argument to the builtin will be optimized to that
> +     constant. This is OK, and means the builtin call is superfluous.
> +     e.g.
> +     struct S foo;
> +     foo.a = 5;
> +     int x = __preserve_access_index (foo.a);
> +     ... do stuff with x
> +     'foo.a' in the builtin argument will be optimized to '5' with -01+.
> +     This sequence does not warrant recording a CO-RE relocation.  */
> +
> +  if (accessors.length () < 1)
> +    return;
> +  accessors.reverse ();
> +
> +  rtx_code_label *label = gen_label_rtx ();
> +  LABEL_PRESERVE_P (label) = 1;
> +  emit_label (label);
> +
> +  /* Determine what output section this relocation will apply to.
> +     If this function is associated with a section, use that. Otherwise,
> +     fall back on '.text'.  */
> +  const char * section_name;
> +  if (current_function_decl && DECL_SECTION_NAME (current_function_decl))
> +    section_name = DECL_SECTION_NAME (current_function_decl);
> +  else
> +    section_name = ".text";
> +
> +  /* Add the CO-RE relocation information to the BTF container.  */
> +  bpf_core_reloc_add (TREE_TYPE (container), section_name, &accessors, label,
> +		      kind);
> +}
> +
> +/* Expand a call to __builtin_preserve_field_info by evaluating the requested
> +   information about SRC according to KIND, and return a tree holding
> +   the result.  */
> +
> +static tree
> +bpf_core_field_info (tree src, enum btf_core_reloc_kind kind)
> +{
> +  unsigned int result;
> +  poly_int64 bitsize, bitpos;
> +  tree var_off = NULL_TREE;
> +  machine_mode mode;
> +  int unsignedp, reversep, volatilep;
> +  location_t loc = EXPR_LOCATION (src);
> +
> +  get_inner_reference (src, &bitsize, &bitpos, &var_off, &mode, &unsignedp,
> +		       &reversep, &volatilep);
> +
> +  /* Note: Use DECL_BIT_FIELD_TYPE rather than DECL_BIT_FIELD here, because it
> +     remembers whether the field in question was originally declared as a
> +     bitfield, regardless of how it has been optimized.  */
> +  bool bitfieldp = (TREE_CODE (src) == COMPONENT_REF
> +		    && DECL_BIT_FIELD_TYPE (TREE_OPERAND (src, 1)));
> +
> +  unsigned int align = TYPE_ALIGN (TREE_TYPE (src));
> +  if (TREE_CODE (src) == COMPONENT_REF)
> +    {
> +      tree field = TREE_OPERAND (src, 1);
> +      if (DECL_BIT_FIELD_TYPE (field))
> +	align = TYPE_ALIGN (DECL_BIT_FIELD_TYPE (field));
> +      else
> +	align = TYPE_ALIGN (TREE_TYPE (field));
> +    }
> +
> +  unsigned int start_bitpos = bitpos & ~(align - 1);
> +  unsigned int end_bitpos = start_bitpos + align;
> +
> +  switch (kind)
> +    {
> +    case BPF_RELO_FIELD_BYTE_OFFSET:
> +      {
> +	if (var_off != NULL_TREE)
> +	  {
> +	    error_at (loc, "unsupported variable field offset");
> +	    return error_mark_node;
> +	  }
> +
> +	if (bitfieldp)
> +	  result = start_bitpos / 8;
> +	else
> +	  result = bitpos / 8;
> +      }
> +      break;
> +
> +    case BPF_RELO_FIELD_BYTE_SIZE:
> +      {
> +	if (mode == BLKmode && bitsize == -1)
> +	  {
> +	    error_at (loc, "unsupported variable size field access");
> +	    return error_mark_node;
> +	  }
> +
> +	if (bitfieldp)
> +	  {
> +	    /* To match LLVM behavior, byte size of bitfields is recorded as
> +	       the full size of the base type. A 3-bit bitfield of type int is
> +	       therefore recorded as having a byte size of 4 bytes. */
> +	    result = end_bitpos - start_bitpos;
> +	    if (result & (result - 1))
> +	      {
> +		error_at (loc, "unsupported field expression");
> +		return error_mark_node;
> +	      }
> +	    result = result / 8;
> +	  }
> +	else
> +	  result = bitsize / 8;
> +      }
> +      break;
> +
> +    case BPF_RELO_FIELD_EXISTS:
> +      /* The field always exists at compile time.  */
> +      result = 1;
> +      break;
> +
> +    case BPF_RELO_FIELD_SIGNED:
> +      result = !unsignedp;
> +      break;
> +
> +    case BPF_RELO_FIELD_LSHIFT_U64:
> +    case BPF_RELO_FIELD_RSHIFT_U64:
> +      {
> +	if (mode == BLKmode && bitsize == -1)
> +	  {
> +	    error_at (loc, "unsupported variable size field access");
> +	    return error_mark_node;
> +	  }
> +	if (var_off != NULL_TREE)
> +	  {
> +	    error_at (loc, "unsupported variable field offset");
> +	    return error_mark_node;
> +	  }
> +
> +	if (!bitfieldp)
> +	  {
> +	    if (bitsize > 64)
> +	      {
> +		error_at (loc, "field size too large");
> +		return error_mark_node;
> +	      }
> +	    result = 64 - bitsize;
> +	    break;
> +	  }
> +
> +	if (end_bitpos - start_bitpos > 64)
> +	  {
> +	    error_at (loc, "field size too large");
> +	    return error_mark_node;
> +	  }
> +
> +	if (kind == BPF_RELO_FIELD_LSHIFT_U64)
> +	  {
> +	    if (TARGET_BIG_ENDIAN)
> +	      result = bitpos + 64 - start_bitpos - align;
> +	    else
> +	      result = start_bitpos + 64 - bitpos - bitsize;
> +	  }
> +	else /* RSHIFT_U64 */
> +	  result = 64 - bitsize;
> +      }
> +      break;
> +
> +    default:
> +      error ("invalid second argument to built-in function");
> +      return error_mark_node;
> +      break;
> +    }
> +
> +  return build_int_cst (unsigned_type_node, result);
> +}
> +
>  /* Expand a call to a BPF-specific built-in function that was set up
>     with bpf_init_builtins.  */
>  
> @@ -1025,17 +1221,15 @@ bpf_expand_builtin (tree exp, rtx target ATTRIBUTE_UNUSED,
>        /* The result of the load is in R0.  */
>        return gen_rtx_REG (ops[0].mode, BPF_R0);
>      }
> +
>    else if (code == -1)
>      {
> -      /* A resolved overloaded builtin, e.g. __bpf_preserve_access_index_si */
> +      /* A resolved overloaded __builtin_preserve_access_index.  */
>        tree arg = CALL_EXPR_ARG (exp, 0);
>  
>        if (arg == NULL_TREE)
>  	return NULL_RTX;
>  
> -      auto_vec<unsigned int, 16> accessors;
> -      tree container;
> -
>        if (TREE_CODE (arg) == SSA_NAME)
>  	{
>  	  gimple *def_stmt = SSA_NAME_DEF_STMT (arg);
> @@ -1049,51 +1243,42 @@ bpf_expand_builtin (tree exp, rtx target ATTRIBUTE_UNUSED,
>        /* Avoid double-recording information if the argument is an access to
>  	 a struct/union marked __attribute__((preserve_access_index)). This
>  	 Will be handled by the attribute handling pass.  */
> -      if (is_attr_preserve_access (arg))
> -	return expand_normal (arg);
> -
> -      container = bpf_core_compute (arg, &accessors);
> -
> -      /* Any valid use of the builtin must have at least one access. Otherwise,
> -	 there is nothing to record and nothing to do. This is primarily a
> -	 guard against optimizations leading to unexpected expressions in the
> -	 argument of the builtin. For example, if the builtin is used to read
> -	 a field of a structure which can be statically determined to hold a
> -	 constant value, the argument to the builtin will be optimized to that
> -	 constant. This is OK, and means the builtin call is superfluous.
> -	 e.g.
> -	   struct S foo;
> -	   foo.a = 5;
> -	   int x = __preserve_access_index (foo.a);
> -	   ... do stuff with x
> -	 'foo.a' in the builtin argument will be optimized to '5' with -01+.
> -	 This sequence does not warrant recording a CO-RE relocation.  */
> -
> -      if (accessors.length () < 1)
> -	return expand_normal (arg);
> -
> -      accessors.reverse ();
> -
> -      container = TREE_TYPE (container);
> -
> -      rtx_code_label *label = gen_label_rtx ();
> -      LABEL_PRESERVE_P (label) = 1;
> -      emit_label (label);
> -
> -      /* Determine what output section this relocation will apply to.
> -	 If this function is associated with a section, use that. Otherwise,
> -	 fall back on '.text'.  */
> -      const char * section_name;
> -      if (current_function_decl && DECL_SECTION_NAME (current_function_decl))
> -	section_name = DECL_SECTION_NAME (current_function_decl);
> +      if (!is_attr_preserve_access (arg))
> +	maybe_make_core_relo (arg, BPF_RELO_FIELD_BYTE_OFFSET);
> +
> +      return expand_normal (arg);
> +    }
> +
> +  else if (code == -2)
> +    {
> +      /* A resolved overloaded __builtin_preserve_field_info.  */
> +      tree src = CALL_EXPR_ARG (exp, 0);
> +      tree kind_tree = CALL_EXPR_ARG (exp, 1);
> +      unsigned HOST_WIDE_INT kind_val;
> +      if (tree_fits_uhwi_p (kind_tree))
> +	kind_val = tree_to_uhwi (kind_tree);
>        else
> -	section_name = ".text";
> +	error ("invalid argument to built-in function");
>  
> -      /* Add the CO-RE relocation information to the BTF container.  */
> -      bpf_core_reloc_add (container, section_name, &accessors, label);
> +      enum btf_core_reloc_kind kind = (enum btf_core_reloc_kind) kind_val;
>  
> -      return expand_normal (arg);
> +      if (TREE_CODE (src) == SSA_NAME)
> +	{
> +	  gimple *def_stmt = SSA_NAME_DEF_STMT (src);
> +	  if (is_gimple_assign (def_stmt))
> +	    src = gimple_assign_rhs1 (def_stmt);
> +	}
> +      if (TREE_CODE (src) == ADDR_EXPR)
> +	src = TREE_OPERAND (src, 0);
> +
> +      tree result = bpf_core_field_info (src, kind);
> +
> +      if (result != error_mark_node)
> +	maybe_make_core_relo (src, kind);
> +
> +      return expand_normal (result);
>      }
> +
>    gcc_unreachable ();
>  }
>  
> @@ -1259,41 +1444,64 @@ bpf_core_get_index (const tree node)
>     __builtin_preserve_access_index.  */
>  
>  static tree
> -bpf_core_newdecl (tree type)
> +bpf_core_newdecl (tree type, bool is_pai)
>  {
> -  tree rettype = build_function_type_list (type, type, NULL);
> +  tree rettype;
>    char name[80];
> -  int len = snprintf (name, sizeof (name), "%s", "__builtin_pai_");
> +  static unsigned long pai_count = 0;
> +  static unsigned long pfi_count = 0;
>  
> -  static unsigned long cnt = 0;
> -  len = snprintf (name + len, sizeof (name) - len, "%lu", cnt++);
> +  if (is_pai)
> +    {
> +      rettype = build_function_type_list (type, type, NULL);
> +      int len = snprintf (name, sizeof (name), "%s", "__builtin_pai_");
> +      len = snprintf (name + len, sizeof (name) - len, "%lu", pai_count++);
> +    }
> +  else
> +    {
> +      rettype = build_function_type_list (unsigned_type_node, type,
> +					  unsigned_type_node, NULL);
> +      int len = snprintf (name, sizeof (name), "%s", "__builtin_pfi_");
> +      len = snprintf (name + len, sizeof (name) - len, "%lu", pfi_count++);
> +    }
>  
> -  return add_builtin_function_ext_scope (name, rettype, -1, BUILT_IN_MD, NULL,
> -					 NULL_TREE);
> +  return add_builtin_function_ext_scope (name, rettype, is_pai ? -1 : -2,
> +					 BUILT_IN_MD, NULL, NULL_TREE);
>  }
>  
>  /* Return whether EXPR could access some aggregate data structure that
>     BPF CO-RE support needs to know about.  */
>  
> -static int
> +static bool
>  bpf_core_is_maybe_aggregate_access (tree expr)
>  {
> -  enum tree_code code = TREE_CODE (expr);
> -  if (code == COMPONENT_REF || code == ARRAY_REF)
> -    return 1;
> -
> -  if (code == ADDR_EXPR)
> +  switch (TREE_CODE (expr))
> +    {
> +    case COMPONENT_REF:
> +    case BIT_FIELD_REF:
> +    case ARRAY_REF:
> +    case ARRAY_RANGE_REF:
> +      return true;
> +    case ADDR_EXPR:
> +    case NOP_EXPR:
>        return bpf_core_is_maybe_aggregate_access (TREE_OPERAND (expr, 0));
> -
> -  return 0;
> +    default:
> +      return false;
> +    }
>  }
>  
> +struct core_walk_data {
> +  location_t loc;
> +  tree arg;
> +};
> +
>  /* Callback function used with walk_tree from bpf_resolve_overloaded_builtin.  */
>  
>  static tree
>  bpf_core_walk (tree *tp, int *walk_subtrees, void *data)
>  {
> -  location_t loc = *((location_t *) data);
> +  struct core_walk_data *dat = (struct core_walk_data *) data;
> +  bool is_pai = dat->arg == NULL_TREE;
>  
>    /* If this is a type, don't do anything. */
>    if (TYPE_P (*tp))
> @@ -1302,10 +1510,18 @@ bpf_core_walk (tree *tp, int *walk_subtrees, void *data)
>        return NULL_TREE;
>      }
>  
> +  /* Build a new function call to a resolved builtin for the desired operation.
> +     If this is a preserve_field_info call, pass along the argument to the
> +     resolved builtin call. */
>    if (bpf_core_is_maybe_aggregate_access (*tp))
>      {
> -      tree newdecl = bpf_core_newdecl (TREE_TYPE (*tp));
> -      tree newcall = build_call_expr_loc (loc, newdecl, 1, *tp);
> +      tree newdecl = bpf_core_newdecl (TREE_TYPE (*tp), is_pai);
> +      tree newcall;
> +      if (is_pai)
> +	newcall = build_call_expr_loc (dat->loc, newdecl, 1, *tp);
> +      else
> +	newcall = build_call_expr_loc (dat->loc, newdecl, 2, *tp, dat->arg);
> +
>        *tp = newcall;
>        *walk_subtrees = 0;
>      }
> @@ -1330,6 +1546,30 @@ bpf_small_register_classes_for_mode_p (machine_mode mode)
>  #define TARGET_SMALL_REGISTER_CLASSES_FOR_MODE_P \
>    bpf_small_register_classes_for_mode_p
>  
> +/* Return whether EXPR is a valid first argument for a call to
> +   __builtin_preserve_field_info.  */
> +
> +static bool
> +bpf_is_valid_preserve_field_info_arg (tree expr)
> +{
> +  switch (TREE_CODE (expr))
> +    {
> +    case COMPONENT_REF:
> +    case BIT_FIELD_REF:
> +    case ARRAY_REF:
> +    case ARRAY_RANGE_REF:
> +      return true;
> +    case NOP_EXPR:
> +      return bpf_is_valid_preserve_field_info_arg (TREE_OPERAND (expr, 0));
> +    case ADDR_EXPR:
> +      /* Do not accept ADDR_EXPRs like &foo.bar, but do accept accesses like
> +	 foo.baz where baz is an array.  */
> +      return (TREE_CODE (TREE_TYPE (TREE_OPERAND (expr, 0))) == ARRAY_TYPE);
> +    default:
> +      return false;
> +    }
> +}
> +
>  /* Implement TARGET_RESOLVE_OVERLOADED_BUILTIN (see gccint manual section
>     Target Macros::Misc.).
>     We use this for the __builtin_preserve_access_index builtin for CO-RE
> @@ -1344,7 +1584,12 @@ bpf_small_register_classes_for_mode_p (machine_mode mode)
>  static tree
>  bpf_resolve_overloaded_builtin (location_t loc, tree fndecl, void *arglist)
>  {
> -  if (DECL_MD_FUNCTION_CODE (fndecl) != BPF_BUILTIN_PRESERVE_ACCESS_INDEX)
> +  bool is_pai = DECL_MD_FUNCTION_CODE (fndecl)
> +    == BPF_BUILTIN_PRESERVE_ACCESS_INDEX;
> +  bool is_pfi = DECL_MD_FUNCTION_CODE (fndecl)
> +    == BPF_BUILTIN_PRESERVE_FIELD_INFO;
> +
> +  if (!is_pai && !is_pfi)
>      return NULL_TREE;
>  
>    /* We only expect one argument, but it may be an arbitrarily-complicated
> @@ -1352,18 +1597,26 @@ bpf_resolve_overloaded_builtin (location_t loc, tree fndecl, void *arglist)
>    vec<tree, va_gc> *params = static_cast<vec<tree, va_gc> *> (arglist);
>    unsigned n_params = params ? params->length() : 0;
>  
> -  if (n_params != 1)
> +  if ((is_pai && n_params != 1) || (is_pfi && n_params != 2))
>      {
> -      error_at (loc, "expected exactly 1 argument");
> -      return NULL_TREE;
> +      error_at (loc, "wrong number of arguments");
> +      return error_mark_node;
>      }
>  
>    tree param = (*params)[0];
>  
> -  /* If not generating BPF_CORE information, the builtin does nothing.  */
> -  if (!TARGET_BPF_CORE)
> +  /* If not generating BPF_CORE information, preserve_access_index does nothing,
> +     and simply "resolves to" the argument.  */
> +  if (!TARGET_BPF_CORE && is_pai)
>      return param;
>  
> +  if (is_pfi && !bpf_is_valid_preserve_field_info_arg (param))
> +    {
> +      error_at (EXPR_LOC_OR_LOC (param, loc),
> +		"argument is not a field access");
> +      return error_mark_node;
> +    }
> +
>    /* Do remove_c_maybe_const_expr for the arg.
>       TODO: WHY do we have to do this here? Why doesn't c-typeck take care
>       of it before or after this hook? */
> @@ -1387,7 +1640,11 @@ bpf_resolve_overloaded_builtin (location_t loc, tree fndecl, void *arglist)
>       This ensures that all the relevant information remains within the
>       expression trees the builtin finally gets.  */
>  
> -  walk_tree (&param, bpf_core_walk, (void *) &loc, NULL);
> +  struct core_walk_data data;
> +  data.loc = loc;
> +  data.arg = is_pai ? NULL_TREE : (*params)[1];
> +
> +  walk_tree (&param, bpf_core_walk, (void *) &data, NULL);
>  
>    return param;
>  }
> @@ -1524,7 +1781,8 @@ handle_attr_preserve (function *fn)
>  		      emit_label (label);
>  
>  		      /* Add the CO-RE relocation information to the BTF container.  */
> -		      bpf_core_reloc_add (container, section_name, &accessors, label);
> +		      bpf_core_reloc_add (container, section_name, &accessors, label,
> +					  BPF_RELO_FIELD_BYTE_OFFSET);
>  		    }
>  		}
>  	    }
> diff --git a/gcc/config/bpf/coreout.cc b/gcc/config/bpf/coreout.cc
> index 8897a045ea1..9f71040846b 100644
> --- a/gcc/config/bpf/coreout.cc
> +++ b/gcc/config/bpf/coreout.cc
> @@ -152,7 +152,8 @@ static GTY (()) vec<bpf_core_section_ref, va_gc> *bpf_core_sections;
>  
>  void
>  bpf_core_reloc_add (const tree type, const char * section_name,
> -		    vec<unsigned int> *accessors, rtx_code_label *label)
> +		    vec<unsigned int> *accessors, rtx_code_label *label,
> +		    enum btf_core_reloc_kind kind)
>  {
>    char buf[40];
>    unsigned int i, n = 0;
> @@ -173,7 +174,7 @@ bpf_core_reloc_add (const tree type, const char * section_name,
>  
>    bpfcr->bpfcr_type = get_btf_id (ctf_lookup_tree_type (ctfc, type));
>    bpfcr->bpfcr_insn_label = label;
> -  bpfcr->bpfcr_kind = BPF_RELO_FIELD_BYTE_OFFSET;
> +  bpfcr->bpfcr_kind = kind;
>  
>    /* Add the CO-RE reloc to the appropriate section.  */
>    bpf_core_section_ref sec;
> diff --git a/gcc/config/bpf/coreout.h b/gcc/config/bpf/coreout.h
> index 3c7bdfd8c2f..498853f6e00 100644
> --- a/gcc/config/bpf/coreout.h
> +++ b/gcc/config/bpf/coreout.h
> @@ -103,7 +103,7 @@ extern void btf_ext_init (void);
>  extern void btf_ext_output (void);
>  
>  extern void bpf_core_reloc_add (const tree, const char *, vec<unsigned int> *,
> -				rtx_code_label *);
> +				rtx_code_label *, enum btf_core_reloc_kind);
>  extern int bpf_core_get_sou_member_index (ctf_container_ref, const tree);
>  
>  #ifdef	__cplusplus
> diff --git a/gcc/doc/extend.texi b/gcc/doc/extend.texi
> index 04af0584d82..d7bc252fb0b 100644
> --- a/gcc/doc/extend.texi
> +++ b/gcc/doc/extend.texi
> @@ -15745,6 +15745,83 @@ Load 32-bits from the @code{struct sk_buff} packet data pointed by the register
>  BPF Compile Once-Run Everywhere (CO-RE) support. Instruct GCC to generate CO-RE relocation records for any accesses to aggregate data structures (struct, union, array types) in @var{expr}. This builtin is otherwise transparent, the return value is whatever @var{expr} evaluates to. It is also overloaded: @var{expr} may be of any type (not necessarily a pointer), the return type is the same. Has no effect if @code{-mco-re} is not in effect (either specified or implied).
>  @end deftypefn
>  
> +@deftypefn {Built-in Function} unsigned int __builtin_preserve_field_info (@var{expr}, unsigned int @var{kind})
> +BPF Compile Once-Run Everywhere (CO-RE) support. This builtin is used to
> +extract information to aid in struct/union relocations.  @var{expr} is
> +an access to a field of a struct or union. Depending on @var{kind}, different
> +information is returned to the program. A CO-RE relocation for the access in
> +@var{expr} with kind @var{kind} is recorded if @code{-mco-re} is in effect.
> +
> +The following values are supported for @var{kind}:
> +@table @var
> +@item FIELD_BYTE_OFFSET = 0
> +The returned value is the offset, in bytes, of the field from the
> +beginning of the containing structure. For bitfields, the byte offset
> +of the containing word.
> +
> +@item FIELD_BYTE_SIZE = 1
> +The returned value is the size, in bytes, of the field. For bitfields,
> +the size in bytes of the containing word.
> +
> +@item FIELD_EXISTENCE = 2
> +The returned value is 1 if the field exists, 0 otherwise. Always 1 at
> +compile time.
> +
> +@item FIELD_SIGNEDNESS = 3
> +The returned value is 1 if the field is signed, 0 otherwise.
> +
> +@item FIELD_LSHIFT_U64 = 4
> +@itemx FIELD_RSHIFT_U64 = 5
> +The returned value is the number of bits of left- or right-shifting
> +respectively needed in order to recover the original value of the field,
> +after it has been loaded by a read of FIELD_BYTE_SIZE bytes into an
> +unsigned 64-bit value. Primarily useful for reading bitfield values
> +from structures which may change between kernel versions.
> +
> +@end table
> +
> +Note that the return value is a constant which is known at
> +compile-time. If the field has a variable offset then
> +FIELD_BYTE_OFFSET, FIELD_LSHIFT_U64 and FIELD_RSHIFT_U64 are not
> +supported. Similarly, if the field has a variable size then
> +FIELD_BYTE_SIZE, FIELD_LSHIFT_U64 and FIELD_RSHIFT_U64 are not
> +supported.
> +
> +For example, __builtin_preserve_field_info can be used to reliably
> +extract bitfield values from a structure which may change between
> +kernel versions:
> +
> +@example
> +struct S
> +@{
> +  short a;
> +  int x:7;
> +  int y:5;
> +@};
> +
> +int
> +read_y (struct S *arg)
> +@{
> +  unsigned long long val;
> +  unsigned int offset = __builtin_preserve_field_info (arg->y, FIELD_BYTE_OFFSET);
> +  unsigned int size = __builtin_presrve_field_info (arg->y, FIELD_BYTE_SIZE);
> +
> +  /* Read size bytes from arg + offset into val.  */
> +  bpf_probe_read (&val, size, arg + offset);
> +
> +  val <<= __builtin_preserve_field_info (arg->y, FIELD_LSHIFT_U64);
> +
> +  if (__builtin_preserve_field_info (arg->y, FIELD_SIGNEDNESS))
> +    val = ((long long) val >> __builtin_preserve_field_info (arg->y, FIELD_RSHIFT_U64));
> +  else
> +    val >>= __builtin_preserve_field_info (arg->y, FIELD_RSHIFT_U64);
> +
> +  return val;
> +@}
> +
> +@end example
> +@end deftypefn
> +
>  @node FR-V Built-in Functions
>  @subsection FR-V Built-in Functions
>  
> diff --git a/gcc/testsuite/gcc.target/bpf/core-builtin-fieldinfo-errors-1.c b/gcc/testsuite/gcc.target/bpf/core-builtin-fieldinfo-errors-1.c
> new file mode 100644
> index 00000000000..2c67c384004
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/bpf/core-builtin-fieldinfo-errors-1.c
> @@ -0,0 +1,23 @@
> +/* { dg-do compile } */
> +/* { dg-options "-O0 -dA -gbtf -mco-re" } */
> +
> +struct F {
> +  int bar;
> +  char c;
> +  int baz;
> +  int arr[];
> +};
> +
> +enum {
> +  FIELD_BYTE_OFFSET = 0,
> +  FIELD_BYTE_SIZE = 1,
> +};
> +
> +unsigned int test (struct F *f) {
> +
> +  unsigned x = __builtin_preserve_field_info (f->arr, FIELD_BYTE_SIZE); /* { dg-error "unsupported variable size field access" } */
> +
> +  unsigned y = __builtin_preserve_field_info (f->baz, 99); /* { dg-error "invalid second argument to built-in function" } */
> +
> +  return x + y;
> +}
> diff --git a/gcc/testsuite/gcc.target/bpf/core-builtin-fieldinfo-errors-2.c b/gcc/testsuite/gcc.target/bpf/core-builtin-fieldinfo-errors-2.c
> new file mode 100644
> index 00000000000..31d7a03b757
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/bpf/core-builtin-fieldinfo-errors-2.c
> @@ -0,0 +1,23 @@
> +/* { dg-do compile } */
> +/* { dg-options "-O0 -dA -gbtf -mco-re" } */
> +
> +struct F {
> +  int bar;
> +  char c;
> +  int baz;
> +};
> +
> +enum {
> +  FIELD_BYTE_OFFSET = 0,
> +  FIELD_BYTE_SIZE = 1,
> +};
> +
> +int test (struct F *f) {
> +  int a;
> +  unsigned x = __builtin_preserve_field_info (({ a = f->bar + f->baz; }), FIELD_BYTE_OFFSET); /* { dg-error "argument is not a field access" } */
> +
> +  int b;
> +  unsigned y = __builtin_preserve_field_info (&(f->c), FIELD_BYTE_SIZE); /* { dg-error "argument is not a field access" } */
> +
> +  return a + b + x + y;
> +}
> diff --git a/gcc/testsuite/gcc.target/bpf/core-builtin-fieldinfo-existence-1.c b/gcc/testsuite/gcc.target/bpf/core-builtin-fieldinfo-existence-1.c
> new file mode 100644
> index 00000000000..c55f21a9c11
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/bpf/core-builtin-fieldinfo-existence-1.c
> @@ -0,0 +1,34 @@
> +/* { dg-do compile } */
> +/* { dg-options "-O0 -dA -gbtf -mco-re" } */
> +
> +enum {
> +  FIELD_EXISTENCE = 2,
> +};
> +
> +typedef unsigned uint;
> +
> +struct S {
> +  unsigned char c;
> +  int d;
> +  uint u;
> +  short ar[3];
> +};
> +
> +unsigned int foo (struct S *s)
> +{
> +  unsigned c  = __builtin_preserve_field_info (s->c, FIELD_EXISTENCE);
> +  unsigned d  = __builtin_preserve_field_info (s->d, FIELD_EXISTENCE);
> +  unsigned u  = __builtin_preserve_field_info (s->u, FIELD_EXISTENCE);
> +  unsigned ar = __builtin_preserve_field_info (s->ar[1], FIELD_EXISTENCE);
> +
> +  return c + d + u + ar;
> +}
> +
> +/* { dg-final { scan-assembler-times "\[\t \]mov\[\t \]%r\[0-9\],1" 4 } } */
> +
> +/* { dg-final { scan-assembler-times "ascii \"0:0.0\"\[\t \]+\[^\n\]*btf_aux_string" 1 } } */
> +/* { dg-final { scan-assembler-times "ascii \"0:1.0\"\[\t \]+\[^\n\]*btf_aux_string" 1 } } */
> +/* { dg-final { scan-assembler-times "ascii \"0:2.0\"\[\t \]+\[^\n\]*btf_aux_string" 1 } } */
> +/* { dg-final { scan-assembler-times "ascii \"0:3:1.0\"\[\t \]+\[^\n\]*btf_aux_string" 1 } } */
> +
> +/* { dg-final { scan-assembler-times "0x2\[\t \]+\[^\n\]*bpfcr_kind" 4 } } */
> diff --git a/gcc/testsuite/gcc.target/bpf/core-builtin-fieldinfo-lshift-1-be.c b/gcc/testsuite/gcc.target/bpf/core-builtin-fieldinfo-lshift-1-be.c
> new file mode 100644
> index 00000000000..dabf73dd259
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/bpf/core-builtin-fieldinfo-lshift-1-be.c
> @@ -0,0 +1,37 @@
> +/* { dg-do compile } */
> +/* { dg-options "-O0 -dA -gbtf -mco-re -mbig-endian" } */
> +
> +struct S {
> +  int x1: 6;
> +  int x2: 3;
> +  int x3: 7;
> +  int x4: 16;
> +};
> +
> +enum {
> +  FIELD_LSHIFT_U64 = 4,
> +};
> +
> +unsigned int foo (struct S *s)
> +{
> +  /* little endian: x1=58, x2=55, x3=48, x4=32 */
> +  /* big endian:    x1=32, x2=38, x3=41, x4=48 */
> +  unsigned x1 = __builtin_preserve_field_info (s->x1, FIELD_LSHIFT_U64);
> +  unsigned x2 = __builtin_preserve_field_info (s->x2, FIELD_LSHIFT_U64);
> +  unsigned x3 = __builtin_preserve_field_info (s->x3, FIELD_LSHIFT_U64);
> +  unsigned x4 = __builtin_preserve_field_info (s->x4, FIELD_LSHIFT_U64);
> +
> +  return x1 + x2 + x3 + x4;
> +}
> +
> +/* { dg-final { scan-assembler-times "\[\t \]mov\[\t \]%r\[0-9\],32" 1 } } */
> +/* { dg-final { scan-assembler-times "\[\t \]mov\[\t \]%r\[0-9\],38" 1 } } */
> +/* { dg-final { scan-assembler-times "\[\t \]mov\[\t \]%r\[0-9\],41" 1 } } */
> +/* { dg-final { scan-assembler-times "\[\t \]mov\[\t \]%r\[0-9\],48" 1 } } */
> +
> +/* { dg-final { scan-assembler-times "ascii \"0:0.0\"\[\t \]+\[^\n\]*btf_aux_string" 1 } } */
> +/* { dg-final { scan-assembler-times "ascii \"0:1.0\"\[\t \]+\[^\n\]*btf_aux_string" 1 } } */
> +/* { dg-final { scan-assembler-times "ascii \"0:2.0\"\[\t \]+\[^\n\]*btf_aux_string" 1 } } */
> +/* { dg-final { scan-assembler-times "ascii \"0:3.0\"\[\t \]+\[^\n\]*btf_aux_string" 1 } } */
> +
> +/* { dg-final { scan-assembler-times "0x4\[\t \]+\[^\n\]*bpfcr_kind" 4 } } */
> diff --git a/gcc/testsuite/gcc.target/bpf/core-builtin-fieldinfo-lshift-1-le.c b/gcc/testsuite/gcc.target/bpf/core-builtin-fieldinfo-lshift-1-le.c
> new file mode 100644
> index 00000000000..99e3982d932
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/bpf/core-builtin-fieldinfo-lshift-1-le.c
> @@ -0,0 +1,37 @@
> +/* { dg-do compile } */
> +/* { dg-options "-O0 -dA -gbtf -mco-re -mlittle-endian" } */
> +
> +struct S {
> +  int x1: 6;
> +  int x2: 3;
> +  int x3: 7;
> +  int x4: 16;
> +};
> +
> +enum {
> +  FIELD_LSHIFT_U64 = 4,
> +};
> +
> +unsigned int foo (struct S *s)
> +{
> +  /* little endian: x1=58, x2=55, x3=48, x4=32 */
> +  /* big endian:    x1=32, x2=38, x3=41, x4=48 */
> +  unsigned x1 = __builtin_preserve_field_info (s->x1, FIELD_LSHIFT_U64);
> +  unsigned x2 = __builtin_preserve_field_info (s->x2, FIELD_LSHIFT_U64);
> +  unsigned x3 = __builtin_preserve_field_info (s->x3, FIELD_LSHIFT_U64);
> +  unsigned x4 = __builtin_preserve_field_info (s->x4, FIELD_LSHIFT_U64);
> +
> +  return x1 + x2 + x3 + x4;
> +}
> +
> +/* { dg-final { scan-assembler-times "\[\t \]mov\[\t \]%r\[0-9\],58" 1 } } */
> +/* { dg-final { scan-assembler-times "\[\t \]mov\[\t \]%r\[0-9\],55" 1 } } */
> +/* { dg-final { scan-assembler-times "\[\t \]mov\[\t \]%r\[0-9\],48" 1 } } */
> +/* { dg-final { scan-assembler-times "\[\t \]mov\[\t \]%r\[0-9\],32" 1 } } */
> +
> +/* { dg-final { scan-assembler-times "ascii \"0:0.0\"\[\t \]+\[^\n\]*btf_aux_string" 1 } } */
> +/* { dg-final { scan-assembler-times "ascii \"0:1.0\"\[\t \]+\[^\n\]*btf_aux_string" 1 } } */
> +/* { dg-final { scan-assembler-times "ascii \"0:2.0\"\[\t \]+\[^\n\]*btf_aux_string" 1 } } */
> +/* { dg-final { scan-assembler-times "ascii \"0:3.0\"\[\t \]+\[^\n\]*btf_aux_string" 1 } } */
> +
> +/* { dg-final { scan-assembler-times "0x4\[\t \]+\[^\n\]*bpfcr_kind" 4 } } */
> diff --git a/gcc/testsuite/gcc.target/bpf/core-builtin-fieldinfo-lshift-2.c b/gcc/testsuite/gcc.target/bpf/core-builtin-fieldinfo-lshift-2.c
> new file mode 100644
> index 00000000000..25be969e22b
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/bpf/core-builtin-fieldinfo-lshift-2.c
> @@ -0,0 +1,37 @@
> +/* { dg-do compile } */
> +/* { dg-options "-O0 -dA -gbtf -mco-re" } */
> +
> +struct S {
> +  char c;
> +  short s;
> +  int x;
> +};
> +
> +union U {
> +  struct S s[2];
> +  long long ll;
> +};
> +
> +enum {
> +  FIELD_LSHIFT_U64 = 4,
> +};
> +
> +unsigned int foo (union U *u)
> +{
> +  /* s0s = 48, s1c = 56, ll = 0; endianness independent.  */
> +  unsigned s0s = __builtin_preserve_field_info (u->s[0].s, FIELD_LSHIFT_U64);
> +  unsigned s1c = __builtin_preserve_field_info (u->s[1].c, FIELD_LSHIFT_U64);
> +  unsigned ll  = __builtin_preserve_field_info (u->ll, FIELD_LSHIFT_U64);
> +
> +  return s0s + s1c + ll;
> +}
> +
> +/* { dg-final { scan-assembler-times "\[\t \]mov\[\t \]%r\[0-9\],48" 1 } } */
> +/* { dg-final { scan-assembler-times "\[\t \]mov\[\t \]%r\[0-9\],56" 1 } } */
> +/* { dg-final { scan-assembler-times "\[\t \]mov\[\t \]%r\[0-9\],0" 1 } } */
> +
> +/* { dg-final { scan-assembler-times "ascii \"0:0:0:1.0\"\[\t \]+\[^\n\]*btf_aux_string" 1 } } */
> +/* { dg-final { scan-assembler-times "ascii \"0:0:1:0.0\"\[\t \]+\[^\n\]*btf_aux_string" 1 } } */
> +/* { dg-final { scan-assembler-times "ascii \"0:1.0\"\[\t \]+\[^\n\]*btf_aux_string" 1 } } */
> +
> +/* { dg-final { scan-assembler-times "0x4\[\t \]+\[^\n\]*bpfcr_kind" 3 } } */
> diff --git a/gcc/testsuite/gcc.target/bpf/core-builtin-fieldinfo-offset-1.c b/gcc/testsuite/gcc.target/bpf/core-builtin-fieldinfo-offset-1.c
> new file mode 100644
> index 00000000000..590eea007ae
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/bpf/core-builtin-fieldinfo-offset-1.c
> @@ -0,0 +1,56 @@
> +/* { dg-do compile } */
> +/* { dg-options "-O0 -dA -gbtf -mco-re" } */
> +
> +struct S {
> +  unsigned int a1: 7;
> +  unsigned int a2: 4;
> +  unsigned int a3: 13;
> +  unsigned int a4: 5;
> +  int x;
> +};
> +
> +struct T {
> +  unsigned int y;
> +  struct S s[2];
> +  char c;
> +  char d;
> +};
> +
> +enum {
> +  FIELD_BYTE_OFFSET = 0,
> +};
> +
> +
> +unsigned int foo (struct T *t)
> +{
> +  unsigned s0a1 = __builtin_preserve_field_info (t->s[0].a1, FIELD_BYTE_OFFSET);
> +  unsigned s0a4 = __builtin_preserve_field_info (t->s[0].a4, FIELD_BYTE_OFFSET);
> +  unsigned s0x  = __builtin_preserve_field_info (t->s[0].x, FIELD_BYTE_OFFSET);
> +
> +  unsigned s1a1 = __builtin_preserve_field_info (t->s[1].a1, FIELD_BYTE_OFFSET);
> +  unsigned s1a4 = __builtin_preserve_field_info (t->s[1].a4, FIELD_BYTE_OFFSET);
> +  unsigned s1x  = __builtin_preserve_field_info (t->s[1].x, FIELD_BYTE_OFFSET);
> +
> +  unsigned c = __builtin_preserve_field_info (t->c, FIELD_BYTE_OFFSET);
> +  unsigned d = __builtin_preserve_field_info (t->d, FIELD_BYTE_OFFSET);
> +
> +  return s0a1 + s0a4 + s0x + s1a1 + s1a4 + s1x + c + d;
> +}
> +
> +/* { dg-final { scan-assembler-times "\[\t \]mov\[\t \]%r\[0-9\],4" 2 } } */
> +/* { dg-final { scan-assembler-times "\[\t \]mov\[\t \]%r\[0-9\],8" 1 } } */
> +/* { dg-final { scan-assembler-times "\[\t \]mov\[\t \]%r\[0-9\],12" 2 } } */
> +/* { dg-final { scan-assembler-times "\[\t \]mov\[\t \]%r\[0-9\],16" 1 } } */
> +/* { dg-final { scan-assembler-times "\[\t \]mov\[\t \]%r\[0-9\],20" 1 } } */
> +/* { dg-final { scan-assembler-times "\[\t \]mov\[\t \]%r\[0-9\],21" 1 } } */
> +
> +/* { dg-final { scan-assembler-times "ascii \"0:1:0:0.0\"\[\t \]+\[^\n\]*btf_aux_string" 1 } } */
> +/* { dg-final { scan-assembler-times "ascii \"0:1:0:3.0\"\[\t \]+\[^\n\]*btf_aux_string" 1 } } */
> +/* { dg-final { scan-assembler-times "ascii \"0:1:0:4.0\"\[\t \]+\[^\n\]*btf_aux_string" 1 } } */
> +/* { dg-final { scan-assembler-times "ascii \"0:1:1:0.0\"\[\t \]+\[^\n\]*btf_aux_string" 1 } } */
> +/* { dg-final { scan-assembler-times "ascii \"0:1:1:3.0\"\[\t \]+\[^\n\]*btf_aux_string" 1 } } */
> +/* { dg-final { scan-assembler-times "ascii \"0:1:1:4.0\"\[\t \]+\[^\n\]*btf_aux_string" 1 } } */
> +/* { dg-final { scan-assembler-times "ascii \"0:2.0\"\[\t \]+\[^\n\]*btf_aux_string" 1 } } */
> +/* { dg-final { scan-assembler-times "ascii \"0:3.0\"\[\t \]+\[^\n\]*btf_aux_string" 1 } } */
> +
> +/* { dg-final { scan-assembler-times "0\[\t \]+\[^\n\]*bpfcr_kind" 8 } } */
> diff --git a/gcc/testsuite/gcc.target/bpf/core-builtin-fieldinfo-rshift-1.c b/gcc/testsuite/gcc.target/bpf/core-builtin-fieldinfo-rshift-1.c
> new file mode 100644
> index 00000000000..d0c75d944cd
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/bpf/core-builtin-fieldinfo-rshift-1.c
> @@ -0,0 +1,36 @@
> +/* { dg-do compile } */
> +/* { dg-options "-O0 -dA -gbtf -mco-re" } */
> +
> +struct S {
> +  int x1: 6;
> +  int x2: 3;
> +  int x3: 7;
> +  int x4: 16;
> +};
> +
> +enum {
> +  FIELD_RSHIFT_U64 = 5,
> +};
> +
> +unsigned int foo (struct S *s)
> +{
> +  /* x1=58, x2=61, x3=57, x4=48; endianness independent.  */
> +  unsigned x1 = __builtin_preserve_field_info (s->x1, FIELD_RSHIFT_U64);
> +  unsigned x2 = __builtin_preserve_field_info (s->x2, FIELD_RSHIFT_U64);
> +  unsigned x3 = __builtin_preserve_field_info (s->x3, FIELD_RSHIFT_U64);
> +  unsigned x4 = __builtin_preserve_field_info (s->x4, FIELD_RSHIFT_U64);
> +
> +  return x1 + x2 + x3 + x4;
> +}
> +
> +/* { dg-final { scan-assembler-times "\[\t \]mov\[\t \]%r\[0-9\],58" 1 } } */
> +/* { dg-final { scan-assembler-times "\[\t \]mov\[\t \]%r\[0-9\],61" 1 } } */
> +/* { dg-final { scan-assembler-times "\[\t \]mov\[\t \]%r\[0-9\],57" 1 } } */
> +/* { dg-final { scan-assembler-times "\[\t \]mov\[\t \]%r\[0-9\],48" 1 } } */
> +
> +/* { dg-final { scan-assembler-times "ascii \"0:0.0\"\[\t \]+\[^\n\]*btf_aux_string" 1 } } */
> +/* { dg-final { scan-assembler-times "ascii \"0:1.0\"\[\t \]+\[^\n\]*btf_aux_string" 1 } } */
> +/* { dg-final { scan-assembler-times "ascii \"0:2.0\"\[\t \]+\[^\n\]*btf_aux_string" 1 } } */
> +/* { dg-final { scan-assembler-times "ascii \"0:3.0\"\[\t \]+\[^\n\]*btf_aux_string" 1 } } */
> +
> +/* { dg-final { scan-assembler-times "0x5\[\t \]+\[^\n\]*bpfcr_kind" 4 } } */
> diff --git a/gcc/testsuite/gcc.target/bpf/core-builtin-fieldinfo-rshift-2.c b/gcc/testsuite/gcc.target/bpf/core-builtin-fieldinfo-rshift-2.c
> new file mode 100644
> index 00000000000..a71ddc17728
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/bpf/core-builtin-fieldinfo-rshift-2.c
> @@ -0,0 +1,35 @@
> +/* { dg-do compile } */
> +/* { dg-options "-O0 -dA -gbtf -mco-re" } */
> +
> +struct S {
> +  int x;
> +  char c;
> +};
> +
> +union U {
> +  int i;
> +  struct S s;
> +};
> +
> +enum {
> +  FIELD_RSHIFT_U64 = 5,
> +};
> +
> +unsigned int foo (union U *u)
> +{
> +  /* sx = 32, sc = 56, i = 32; endianness independent.  */
> +  unsigned sx = __builtin_preserve_field_info (u->s.x, FIELD_RSHIFT_U64);
> +  unsigned sc = __builtin_preserve_field_info (u->s.c, FIELD_RSHIFT_U64);
> +  unsigned i  = __builtin_preserve_field_info (u->i, FIELD_RSHIFT_U64);
> +
> +  return sx + sc + i;
> +}
> +
> +/* { dg-final { scan-assembler-times "\[\t \]mov\[\t \]%r\[0-9\],32" 2 } } */
> +/* { dg-final { scan-assembler-times "\[\t \]mov\[\t \]%r\[0-9\],56" 1 } } */
> +
> +/* { dg-final { scan-assembler-times "ascii \"0:1:0.0\"\[\t \]+\[^\n\]*btf_aux_string" 1 } } */
> +/* { dg-final { scan-assembler-times "ascii \"0:1:1.0\"\[\t \]+\[^\n\]*btf_aux_string" 1 } } */
> +/* { dg-final { scan-assembler-times "ascii \"0:0.0\"\[\t \]+\[^\n\]*btf_aux_string" 1 } } */
> +
> +/* { dg-final { scan-assembler-times "0x5\[\t \]+\[^\n\]*bpfcr_kind" 3 } } */
> diff --git a/gcc/testsuite/gcc.target/bpf/core-builtin-fieldinfo-sign-1.c b/gcc/testsuite/gcc.target/bpf/core-builtin-fieldinfo-sign-1.c
> new file mode 100644
> index 00000000000..3b2081e197c
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/bpf/core-builtin-fieldinfo-sign-1.c
> @@ -0,0 +1,33 @@
> +/* { dg-do compile } */
> +/* { dg-options "-O0 -dA -gbtf -mco-re" } */
> +
> +enum {
> +  FIELD_SIGNEDNESS = 3,
> +};
> +
> +typedef unsigned uint;
> +
> +struct S {
> +  unsigned char c;
> +  int d;
> +  uint u;
> +  short ar[3];
> +};
> +
> +unsigned int foo (struct S *s)
> +{
> +  unsigned d  = __builtin_preserve_field_info (s->d, FIELD_SIGNEDNESS);
> +  unsigned u  = __builtin_preserve_field_info (s->u, FIELD_SIGNEDNESS);
> +  unsigned ar = __builtin_preserve_field_info (s->ar[1], FIELD_SIGNEDNESS);
> +
> +  return d + u + ar;
> +}
> +
> +/* { dg-final { scan-assembler-times "\[\t \]mov\[\t \]%r\[0-9\],1" 2 } } */
> +/* { dg-final { scan-assembler-times "\[\t \]mov\[\t \]%r\[0-9\],0" 1 } } */
> +
> +/* { dg-final { scan-assembler-times "ascii \"0:1.0\"\[\t \]+\[^\n\]*btf_aux_string" 1 } } */
> +/* { dg-final { scan-assembler-times "ascii \"0:2.0\"\[\t \]+\[^\n\]*btf_aux_string" 1 } } */
> +/* { dg-final { scan-assembler-times "ascii \"0:3:1.0\"\[\t \]+\[^\n\]*btf_aux_string" 1 } } */
> +
> +/* { dg-final { scan-assembler-times "0x3\[\t \]+\[^\n\]*bpfcr_kind" 3 } } */
> diff --git a/gcc/testsuite/gcc.target/bpf/core-builtin-fieldinfo-sign-2.c b/gcc/testsuite/gcc.target/bpf/core-builtin-fieldinfo-sign-2.c
> new file mode 100644
> index 00000000000..bf184299984
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/bpf/core-builtin-fieldinfo-sign-2.c
> @@ -0,0 +1,45 @@
> +/* { dg-do compile } */
> +/* { dg-options "-O0 -dA -gbtf -mco-re" } */
> +
> +enum {
> +  FIELD_SIGNEDNESS = 3,
> +};
> +
> +enum Esig {
> +  SA = -1,
> +  SB,
> +  SC,
> +};
> +
> +enum Eun {
> +  UA = 0,
> +  UB,
> +};
> +
> +struct S {
> +  enum Esig sig : 3;
> +  enum Eun un : 3;
> +};
> +
> +union U {
> +  int i;
> +  struct S s;
> +};
> +
> +unsigned int foo (union U *u)
> +{
> +  unsigned i   = __builtin_preserve_field_info (u->i, FIELD_SIGNEDNESS);
> +  unsigned sig = __builtin_preserve_field_info (u->s.sig, FIELD_SIGNEDNESS);
> +  unsigned un  = __builtin_preserve_field_info (u->s.un, FIELD_SIGNEDNESS);
> +
> +  return i + sig + un;
> +}
> +
> +/* { dg-final { scan-assembler-times "\[\t \]mov\[\t \]%r\[0-9\],1" 2 } } */
> +/* { dg-final { scan-assembler-times "\[\t \]mov\[\t \]%r\[0-9\],0" 1 } } */
> +
> +/* { dg-final { scan-assembler-times "ascii \"0:0.0\"\[\t \]+\[^\n\]*btf_aux_string" 1 } } */
> +/* { dg-final { scan-assembler-times "ascii \"0:1:0.0\"\[\t \]+\[^\n\]*btf_aux_string" 1 } } */
> +/* { dg-final { scan-assembler-times "ascii \"0:1:1.0\"\[\t \]+\[^\n\]*btf_aux_string" 1 } } */
> +
> +/* { dg-final { scan-assembler-times "3\[\t \]+\[^\n\]*bpfcr_kind" 3 } } */
> diff --git a/gcc/testsuite/gcc.target/bpf/core-builtin-fieldinfo-size-1.c b/gcc/testsuite/gcc.target/bpf/core-builtin-fieldinfo-size-1.c
> new file mode 100644
> index 00000000000..8747bdeb9c3
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/bpf/core-builtin-fieldinfo-size-1.c
> @@ -0,0 +1,43 @@
> +/* { dg-do compile } */
> +/* { dg-options "-O0 -dA -gbtf -mco-re" } */
> +
> +struct S {
> +  unsigned int a1: 7;
> +  unsigned int a2: 4;
> +  unsigned int a3: 13;
> +  unsigned int a4: 5;
> +  char carr[5][3];
> +};
> +
> +enum {
> +  FIELD_BYTE_SIZE = 1,
> +};
> +
> +union U {
> +  long long l[3];
> +  struct S s;
> +};
> +
> +unsigned int foo (union U *u)
> +{
> +  unsigned ls = __builtin_preserve_field_info (u->l, FIELD_BYTE_SIZE);
> +  unsigned s  = __builtin_preserve_field_info (u->s, FIELD_BYTE_SIZE);
> +  unsigned a2 = __builtin_preserve_field_info (u->s.a2, FIELD_BYTE_SIZE);
> +  unsigned a3 = __builtin_preserve_field_info (u->s.a3, FIELD_BYTE_SIZE);
> +  unsigned ca = __builtin_preserve_field_info (u->s.carr, FIELD_BYTE_SIZE);
> +
> +  return ls + s + a2 + a3 + ca;
> +}
> +
> +/* { dg-final { scan-assembler-times "\[\t \]mov\[\t \]%r\[0-9\],24" 1 } } */
> +/* { dg-final { scan-assembler-times "\[\t \]mov\[\t \]%r\[0-9\],20" 1 } } */
> +/* { dg-final { scan-assembler-times "\[\t \]mov\[\t \]%r\[0-9\],4" 2 } } */
> +/* { dg-final { scan-assembler-times "\[\t \]mov\[\t \]%r\[0-9\],15" 1 } } */
> +
> +/* { dg-final { scan-assembler-times "ascii \"0:0.0\"\[\t \]+\[^\n\]*btf_aux_string" 1 } } */
> +/* { dg-final { scan-assembler-times "ascii \"0:1.0\"\[\t \]+\[^\n\]*btf_aux_string" 1 } } */
> +/* { dg-final { scan-assembler-times "ascii \"0:1:1.0\"\[\t \]+\[^\n\]*btf_aux_string" 1 } } */
> +/* { dg-final { scan-assembler-times "ascii \"0:1:2.0\"\[\t \]+\[^\n\]*btf_aux_string" 1 } } */
> +/* { dg-final { scan-assembler-times "ascii \"0:1:4.0\"\[\t \]+\[^\n\]*btf_aux_string" 1 } } */
> +
> +/* { dg-final { scan-assembler-times "0x1\[\t \]+\[^\n\]*bpfcr_kind" 5 } } */
  

On 10/26/22 12:33, Jose E. Marchesi wrote:
> 
> Hi David.
> 
> Thanks for the updates.
> OK for master.
> 

Pushed, thanks.