On 1/5/23 10:30 AM, Jose E. Marchesi wrote:
We agreed in the meeting to implement Solution 2 below in both GCC and clang. The DW_TAG_LLVM_annotation DIE number will be changed in order to make it possible for pahole to handle the current tags. The number of the new tag will be shared by both GCC and clang.
w.r.t c2x attribute syntax discussion in 01/19 office hour discussion. I have checked clang c2x syntax w.r.t. btf_type_tag and btf_decl_tag. They are both supported with clang 15 and 16. See: https://clang.llvm.org/docs/AttributeReference.html The c2x btf_decl_tag attr syntax is [[clang::btf_decl_tag("")]]. The c2x btf_type_tag attr syntax is [[clang::btf_type_tag("")]]. $ cat t.c int [[clang::btf_type_tag("aa")]] * [[clang::btf_type_tag("bb")]] *f; [[clang::btf_decl_tag("cc")]] int foo() { return 5; } int bar() { return foo(); } $ clang -std=c2x -g -O2 -c t.c $ llvm-dwarfdump t.o | grep btf | grep tag DW_AT_name ("btf_type_tag") DW_AT_name ("btf_type_tag") DW_AT_name ("btf_decl_tag") I double checked and the c2x syntax above generates the *same* type IR and dwarf compared to __attribute__ style attributes. [...]
