bpf: Fix CO-RE field expression builtins

This patch corrects bugs within the CO-RE builtin field expression
related builtins.
The following bugs were identified and corrected based on the expected
results of bpf-next selftests testsuite.
It addresses the following problems:
 - Expressions with pointer dereferencing now point to the BTF structure
   type, instead of the structure pointer type.
 - Pointer addition to structure root is now identified and constructed
   in CO-RE relocations as if it is an array access. For example,
  "&(s+2)->b" generates "2:1" as an access string where "2" is
  refering to the access for "s+2".

gcc/ChangeLog:
	* config/bpf/core-builtins.cc (core_field_info): Add
	support for POINTER_PLUS_EXPR in the root of the field expression.
	(bpf_core_get_index): Likewise.
	(pack_field_expr): Make the BTF type to point to the structure
	related node, instead of its pointer type.
	(make_core_safe_access_index): Correct to new code.

gcc/testsuite/ChangeLog:
	* gcc.target/bpf/core-attr-5.c: Correct.
	* gcc.target/bpf/core-attr-6.c: Likewise.
	* gcc.target/bpf/core-attr-struct-as-array.c: Add test case for
	pointer arithmetics as array access use case.

0 files changed, 0 insertions, 0 deletions