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Currently, the CO-RE offset relocation does not work if any struct/union member or array element is a typedef. For example, typedef const int arr_t[7]; struct input { arr_t a; }; func(...) { struct input *in = ...; ... __builtin_preserve_access_index(&in->a[1]) ... } The BPF backend calculated default offset is 0 while 4 is the correct answer. Similar issues exist for struct/union typedef's. When getting struct/union member or array element type, we should trace down to the type by skipping typedef and qualifiers const/volatile as this is what clang did to generate getelementptr instructions. (const/volatile member type qualifiers are already ignored by clang.) This patch fixed this issue, for each access index, skipping typedef and const/volatile/restrict BTF types. Signed-off-by: Yonghong Song <yhs@fb.com> Differential Revision: https://reviews.llvm.org/D65259 llvm-svn: 367062