On Fri, 24 Feb 2023 05:09:30 PST (-0800), gcc-patches@gcc.gnu.org wrote:
It did help people to identify what extension used in the binary, so I would prefer keep that enable by default.
IMO it actually hurts more than helps, as it's not really encoding what extensions are in the binary (or necessary to run the binary) but instead just encodes what was in -march (with some noise added due to the merging bugs and ISA string changes). Having the attributes just ends up tricking users into thinking the information is accurate when it's not.
and lld is begin fix those merge issue, so the situation should be improved soon.
If toolchains are just going to ignore then attributes then it's a pretty good sign they're not useful.
Palmer Dabbelt <pal...@rivosinc.com> 於 2023年2月24日 週五 10:29 寫道：We generate a handful of attributes by default, but they don't really encode any useful information. We've broadly stopped ascribing any meaning to them in binutils; but they trip up LLVM, older toolchains, and users. So let's just turn them off by default. The old binaries will still be floating around, but at least this way we'll stop tripping over new incompatibilities. If we get to a point where there's some attributes that are defined that we can use then we can sort out how to turn those on without turning on the old ones, but unless I'm missing something the current set of attributes are too broken to be useful for anything. gcc/ChangeLog: * config.gcc (--with-riscv-attribute): Default to off. --- I know it's pretty late, but I'd like to target this for GCC-13. The Zmmul stuff has resulted in another round of build breakages that we're going to have to chase down, and while we could update everything to turn off the attributes it seems easier to just set the default. --- gcc/config.gcc | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/gcc/config.gcc b/gcc/config.gcc index c070e6ecd2e..52639cf26d6 100644 --- a/gcc/config.gcc +++ b/gcc/config.gcc @@ -4596,7 +4596,7 @@ case "${target}" in tm_defines="${tm_defines} TARGET_RISCV_ATTRIBUTE=0" ;; ""|default) - tm_defines="${tm_defines} TARGET_RISCV_ATTRIBUTE=1" + tm_defines="${tm_defines} TARGET_RISCV_ATTRIBUTE=0" ;; *) echo "--with-riscv-attribute=${with_riscv_attribute} is not supported. The argument must begin with yes, no or default." 1>&2 -- 2.39.1
